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Introduction to Physical Science/Review

This is the final chapter of a wikibook entitled Basics Physics of Nuclear Medicine, written originally by [mailto:kieranmaher@mac.com Kieran Maher] in 1997.

Chapter Review: Atomic & Nuclear Structure

 * The atom consists of two components - a nucleus (positively charged) and an electron cloud (negatively charged);
 * The radius of the nucleus is about 10,000 times smaller than that of the atom;
 * The nucleus can have two component particles - neutrons (no charge) and protons (positively charged) - collectively called nucleons;
 * The mass of a proton is about equal to that of a neutron - and is about 1,840 times that of an electron;
 * The number of protons equals the number of electrons in an isolated atom;
 * The Atomic Number specifies the number of protons in a nucleus;
 * The Mass Number specifies the number of nucleons in a nucleus;
 * Isotopes of elements have the same atomic number but different mass numbers;
 * Isotopes are classified by specifying the element's chemical symbol preceded by a superscript giving the mass number and a subscript giving the atomic number;
 * The atomic mass unit is defined as 1/12th the mass of the stable, most commonly occurring isotope of carbon (i.e. C-12);
 * Binding energy is the energy which holds the nucleons together in a nucleus and is measured in electron volts (eV);
 * To combat the effect of the increase in electrostatic repulsion as the number of protons increases, the number of neutrons increases more rapidly - giving rise to the Nuclear Stability Curve;
 * There are ~2450 isotopes of ~100 elements and the unstable isotopes lie above or below the Nuclear Stability Curve;
 * Unstable isotopes attempt to reach the stability curve by splitting into fragments (fission) or by emitting particles/energy (radioactivity);
 * Unstable isotopes <=> radioactive isotopes <=> radioisotopes <=> radionuclides;
 * ~300 of the ~2450 isotopes are found in nature - the rest are produced artificially.

Chapter Review: Radioactive Decay

 * Fission: Some heavy nuclei decay by splitting into 2 or 3 fragments plus some neutrons. These fragments form new nuclei which are usually radioactive;
 * Alpha Decay: Two protons and two neutrons leave the nucleus together in an assembly known as an alpha-particle;
 * An alpha-particle is a He-4 nucleus;
 * Beta Decay - Electron Emission: Certain nuclei with an excess of neutrons may reach stability by converting a neutron into a proton with the emission of a beta-minus particle;
 * A beta-minus particle is an electron;
 * Beta Decay - Positron Emission: When the number of protons in a nucleus is in excess, the nucleus may reach stability by converting a proton into a neutron with the emission of a beta-plus particle;
 * A beta-plus particle is a positron;
 * Positrons annihilate with electrons to produce two back-to-back gamma-rays;
 * Beta Decay - Electron Capture: An inner orbital electron is attracted into the nucleus where it combines with a proton to form a neutron;
 * Electron capture is also known as K-capture;
 * Following electron capture, the excited nucleus may give off some gamma-rays. In addition, as the vacant electron site is filled, an X-ray is emitted;
 * Gamma Decay - Isomeric Transition: A nucleus in an excited state may reach its ground state by the emission of a gamma-ray;
 * A gamma-ray is an electromagnetic photon of high energy;
 * Gamma Decay - Internal Conversion: the excitation energy of an excited nucleus is given to an atomic electron.

Chapter Review: The Radioactive Decay Law

 * The radioactive decay law in equation form;
 * Radioactivity is the number of radioactive decays per unit time;
 * The decay constant is defined as the fraction of the initial number of radioactive nuclei which decay in unit time;
 * Half Life: The time taken for the number of radioactive nuclei in the sample to reduce by a factor of two;
 * Half Life = (0.693)/(Decay Constant);
 * The SI Unit of radioactivity is the becquerel (Bq)
 * 1 Bq = one radioactive decay per second;
 * The traditional unit of radioactivity is the curie (Ci);
 * 1 Ci = 3.7 x 1010 radioactive decays per second.

Chapter Review: Units of Radiation Measurement

 * Exposure expresses the intensity of an X- or gamma-ray beam;
 * The SI unit of exposure is the coulomb per kilogram (C/kg);
 * 1 C/kg = The quantity of X- or gamma-rays such that the associated electrons emitted per kg of air at STP produce in air ions carrying 1 coulomb of electric charge;
 * The traditional unit of exposure is the roentgen (R);
 * 1 R = The quantity of X- or gamma-rays such that the associated electrons emitted per kg of air at STP produce in air ions carrying 2.58 x 10-4 coulombs of electric charge;
 * The exposure rate is the exposure per unit time, e.g. C/kg/s;
 * Absorbed dose is the radiation energy absorbed per unit mass of absorbing material;
 * The SI unit of absorbed dose is the gray (Gy);
 * 1 Gy = The absorption of 1 joule of radiation energy per kilogram of material;
 * The traditional unit of absorbed dose is the rad;
 * 1 rad = The absorption of 10-2 joules of radiation energy per kilogram of material;
 * The Specific Gamma-Ray Constant expresses the exposure rate produced by the gamma-rays from a radioisotope;
 * The Specific Gamma-Ray Constant is expressed in SI units in C/kg/s/Bq at 1 m;
 * Exposure from an X- or gamma-ray source follows the Inverse Square Law and decreases with the square of the distance from the source.

Chapter Review: Interaction of Radiation with Matter

 * Alpha-Particles:
 * exert considerable electrostatic attraction on the outer orbital electrons of atoms near which they pass and cause ionisations;
 * travel in straight lines - except for rare direct collisions with nuclei of atoms in their path;
 * energy is always discrete.
 * Beta-Minus Particles:
 * attracted by nuclei and repelled by electron clouds as they pass through matter and cause ionisations;
 * have a tortuous path;
 * have a range of energies;
 * range of energies results because two particles are emitted - a beta-particle and a neutrino.
 * Gamma-Rays:
 * energy is always discrete;
 * have many modes of interaction with matter;
 * important interactions for nuclear medicine imaging (and radiography) are the Photoelectric Effect and the Compton Effect.
 * Photoelectric Effect:
 * when a gamma-ray collides with an orbital electron, it may transfer all its energy to the electron and cease to exist;
 * the electron can leave the atom with a kinetic energy equal to the energy of the gamma-ray less the orbital binding energy;
 * a positive ion is formed when the electron leaves the atom;
 * the electron is called a photoelectron;
 * the photoelectron can cause further ionisations;
 * subsequent X-ray emission as the orbital vacancy is filled.
 * Compton Effect:
 * A gamma-ray may transfer only part of its energy to a valence electron which is essentially free; ** gives rise to a scattered gamma-ray;
 * is sometimes called Compton Scatter;
 * a positive ion results;
 * Attenuation is term used to describe both absorption and scattering of radiation.

Chapter Review: Attenuation of Gamma-Rays

 * Attenuation of a narrow-beam of gamma-rays increases as the thickness, the density and the atomic number of the absorber increases;
 * Attenuation of a narrow-beam of gamma-rays decreases as the energy of the gamma-rays increases;
 * Attenuation of a narrow beam is described by an equation;
 * the Linear Attenuation Coefficient is defined as the fraction of the incident intensity absorbed in a unit distance of the absorber;
 * Linear attenuation coefficients are usually expressed in units of cm-1;
 * the Half Value Layer is the thickness of absorber required to reduce the intensity of a radiation beam by a factor of 2;
 * Half Value Layer = (0.693)/(Linear Attenuation Coefficient);
 * the Mass Attenuation Coefficient is given by the linear attenuation coefficient divided by the density of the absorber;
 * Mass attenuation coefficients are usually expressed in units of cm2 g-1.

Chapter Review: Gas-Filled Detectors

 * Gas-filled detectors include the ionisation chamber, the proportional counter and the Geiger counter;
 * They operate on the basis of ionisation of gas atoms by the incident radiation, where the positive ions and electrons produced are collected by electrodes;
 * An ion pair is the term used to describe a positive ion and an electron;
 * The operation of gas-filled detectors is critically dependent on the magnitude of the applied dc voltage;
 * The output voltage of an ionisation chamber can be calculated on the basis of the capacitance of the chamber;
 * A very sensitive amplifier is required to measure voltage pulses produced by an ionisation chamber;
 * The gas in ionisation chambers is usually air;
 * Ionisation chambers are typically used to measure radiation exposure (in a device called an Exposure Meter) and radioactivity (in a device called an Isotope Calibrator);
 * The total charge collected in a proportional counter may be up to 1000 times the charge produced initially by the radiation;
 * The initial ionisation triggers a complete gas breakdown in a Geiger counter;
 * The gas in a Geiger counter is usually an inert gas;
 * The gas breakdown must be stopped in order to prepare the Geiger counter for a new event by a process called quenching;
 * Two types of quenching are possible: electronic quenching and the use of a quenching gas;
 * Geiger counters suffer from dead time, a small period of time following the gas breakdown when the counter is inoperative;
 * The true count rate can be determined from the actual count rate and the dead time using an equation;
 * The value of the applied dc voltage in a Geiger counter is critical, but high stability is not required.

Chapter Review: Scintillation Detectors

 * NaI(Tl) is a scintillation crystal widely used in nuclear medicine;
 * The crystal is coupled to a photomultiplier tube to generate a voltage pulse representing the energy deposited in the crystal by the radiation;
 * A very sensitive amplifier is needed to measure such voltage pulses;
 * The voltages pulses range in amplitude depending on how the radiation interacts with the crystal, i.e. the pulses form a spectrum whose shape depends on the interaction mechanisms involved, e.g. for medium-energy gamma-rays used in in-vivo nuclear medicine: the Compton effect and the Photoelectric effect;
 * A Gamma-Ray Energy Spectrum for a medium-energy, monoenergetic gamma-ray emitter consists (simply) of a Compton Smear and a Photopeak;
 * Pulse Height Analysis is used to discriminate the amplitude of voltage pulses;
 * A pulse height analyser (PHA) consists of a lower level discriminator (which passes voltage pulses which are than its setting) and an upper level discriminator (which passes voltage pulses lower than its setting);
 * The result is a variable width window which can be placed anywhere along a spectrum, or used to scan a spectrum;
 * A single channel analyser (SCA) consists of a single PHA with a scaler and a ratemeter;
 * A multi-channel analyser (MCA) is a computer-controlled device which can acquire data from many windows simultaneously.

Chapter Review: Nuclear Medicine Imaging Systems

 * A gamma camera consists of a large diameter (25-40 cm) NaI(Tl) crystal, ~1 cm thick;
 * The crystal is viewed by an array of 37-91 PM tubes;
 * PM tubes signals are processed by a position circuit which generates +/- X and +/- Y signals;
 * These position signals are summed to form a Z signal which is fed to a pulse height analyser;
 * The +/- X, +/- Y and discriminated Z signals are sent to a computer for digital image processing;
 * A collimator is used to improve the spatial resolution of a gamma-camera;
 * Collimators typically consist of a Pb plate containing a large number of small holes;
 * The most common type is a parallel multi-hole collimator;
 * The most resolvable area is directly in front of a collimator;
 * Parallel-hole collimators vary in terms of the number of holes, the hole diameter, the length of each hole and the septum thickness - the combination of which affect the sensitivity and spatial resolution of the imaging system;
 * Other types include the diverging-hole collimator (which generates minified images), the converging-hole collimator (which generates magnified images) and the pin-hole collimator (which generates magnified inverted images);
 * Conventional imaging with a gamma camera is referred to as Planar Imaging, i.e. a 2D image portraying a 3D object giving superimposed details and no depth information;
 * Single Photon Emission Computed Tomography (SPECT) produces images of slices through the body;
 * SPECT uses a gamma camera to record images at a series of angles around the patient;
 * The resultant data can be processed using a Filtered Back Projection method;
 * SPECT gamma-cameras can have one, two or three camera heads;
 * Positron Emission Tomography (PET) also produces images of slices through the body;
 * PET exploits the positron annihilation process where two 0.51 MeV back-to-back gamma-rays are produced;
 * If these gamma-rays are detected, their origin will lie on a line joining two of the detectors of the ring of detectors which encircles the patient;
 * A Time-of-Flight method can be used to localise their origin;
 * PET systems require on-site or nearby cyclotron to produce short-lived radioisotopes, such as C-11, N-13, O-15 and F-18.

Chapter Review: Production of Radioisotopes

 * Naturally-occurring radioisotopes generally have long half lives and belong to relatively heavy elements - and are therefore unsuitable for medical diagnostic applications;
 * Medical diagnostic radioisotopes are generally produced artificially;
 * The fission process can be exploited so that radioisotopes of interest can be separated chemically from fission products;
 * A cyclotron can be used to accelerate charged particles up to high energies so that they to collide into a target of the material to be activated;
 * A radioisotope generator is generally used in hospitals to produce short-lived radioisotopes;
 * A technetium-99m generator consists of an alumina column containing Mo-99, which decays into Tc-99m;
 * Saline is passed through the generator to elute the Tc-99m - the resulting solution is called sodium pertechnetate;
 * Both positive pressure and negative pressure generators are in use;
 * An isotope calibrator is needed when a Tc-99m generator is used in order to determine the activity for preparation of patient doses and to test whether any Mo-99 is present in the collected solution.

title: Introduction to Physical Science/Review


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Managing Groups and Teams/Diversity

What Is Diversity?
Team Diversity is the significant uniqueness of each individual on a team. This should not only include the usual diverse selections such as religion, sex, age, and race, but also additional unique personality characteristics such as introverts and extroverts, liberals and conservatives, etc. All of these differences can affect team interactions and performance. However, not all differences affect team performance. For the purposes of this chapter, differences are considered to affect diversity when they significantly affect team performance.

How Are Diverse Teams Different From Homogeneous Ones?
Aside from the actual differences that create diversity, diverse teams have different challenges, benefits, and pitfalls than homogeneous ones. The main benefit is that a diverse background fosters a creative environment. The main pitfall is that differences between team members can lead to destructive violence. The differences that are most commonly thought of as separating diverse teams from homogeneous ones are easily observed stereotypes. The following list categorizes the physical and social differences (excluding actual workplace experience) that most frequently create a diverse environment:

 * Gender : Gender communication issues can strongly affect team interactions. Gender communication issues can range from communication styles and perceptions, opportunities and even sexual harassment.

 * Race : Race is defined as a group of people, often of a common geographic origin, that share genetically transmitted physical characteristics. Racism is the belief that these inherited characteristics affect an individual’s behavior or abilities.

 * Cultural : Culture refers to the standards of social interaction, value and beliefs from a given group of people. Cultural issues can affect team interactions through different understandings of communication or family and can appear to be an excuse for preferential treatment.

 * Age : Age can be a concern along the entire spectrum; is someone too young or too old to do a job? It also creates the potential for communication problems based on different levels of experience, and for prejudicial treatment based on age.

 * Sexual orientation : With the increasing visibility of gender minorities such as lesbian, gay, bisexual, transgender, there are increasing workplace issues. From simply not understanding gender differences, to being morally opposed to them, sexual orientation can create blocks to productive team interactions.

 * Disabilities : Differences in ability often create difficulties in communication and emotional interactions. Whether it is a deaf individual not being able to communicate with hearing individuals, or a hearing individual being unsure of how to approach a deaf individual, disabilities present a variety of issues in team organizations.

By definition, diversity means that there will be an increased likelihood for a wider range of views to be present. This includes views that are likely to challenge widely accepted views of the team and its culture. The existence of these diverse views is essential to the process of organizational change. In addition, as teams are becoming increasingly global, diversity can help an organization or team to understand its place in its surroundings.

The differences inherent in a diverse team environment also cause challenges. The benefits of having diverse backgrounds do not occur without having team members that are dedicated to success and a common goal. The preconceived notions about differences in other people, such as racism, sexism, ageism, homophobia, etc, disrupt work processes and can prevent teams from achieving their goals. Simple misunderstandings can arise from basic cultural differences, communication styles or work attitudes, and create challenge. Diversity in teams has benefits and creates challenges. However, by being aware of these challenges and how to address them, teams and team managers can overcome them and reach success.

Team Relationships
In today’s job market, leaders must be especially aware of diversity, and how to manage it to the best effect. How can leaders do this? First they need to focus on treating every individual fairly and respectfully. In the article "Handling Conflict in a Diverse Work Environment", published in Black Enterprise Magazine, Marcia Pledger suggests the following.

First, leaders need to establish relationships of trust with their employees. If an employee does not trust his leader, they will not be able to discuss issues of real significance. There will always be a wall between the leader and the employee that will result in strained relationships over the long run.

The United States Marine Corps faced this problem in the early 1990’s. In answer to this problem, the Marine Corps instituted a new training program titled “Team Marine” that helped the Marine leadership focus on what their subordinates brought to their teams. They developed a set of expectations as to what belonging to Corps meant:

 * We expect to actively contribute to the team and to be recognized for our contributions.
 * We expect to be judged fairly and to be recognized and rewarded for our performance.
 * We expect the opportunity to develop our abilities.
 * We expect to be treated professionally and respectfully by other members of our team.
 * We expect to be valued as unique individuals.

By following this set of principles the Marine Corps has managed to take what is one of the most diverse workforces in the world and unified them as contributing individuals with a common goal.

Leaders need to seek input from their employees on how they prefer to be managed. In the article "Dealing with the New Diversity", author Michael Maccoby relates the story of an engineering company that was the result of a merger between a German, Swiss and Swedish firm. The management styles differed between each of the original companies based upon their nation of origin. This lead to many problems as engineers from one country were asked to serve under leaders from another. The company was not able to perform at its best until they discussed their differences and were able to determine a common management style for the entire company.

Leaders need to develop a common focus. Most people realize that everyone is different; however, by focusing on the job at hand, leaders can take the focus off the differences that are present. As teams achieve successful results they develop a bond which helps to solidify the team, and overcome differences.

Team Structure
In a diverse team, as with any team, communication needs to be open and safe. It is the team leader's responsibility to set up this safe environment. The team leader should instill confidence in the other members that what they are thinking can be discussed “as long as it is done respectfully.”

Behaviors should be agreed upon before an "open and safe" discussion begins so all members are aware of what is expected of them, and how to remain respectful. This can be done through the use of a Team Contract, an agreed upon document that outlines the rules for communication and the consequences of not living up to the agreement.

Included in this contract there needs to be an agreed upon a way for members to respectfully stop someone who is not living up to their part of the agreement, and redirect the conversation towards the tasks needing to be accomplished. Anyone in the group should feel comfortable in enforcing the rules of the contract, and ensuring the discussion remains respectful.

While working in a diverse team there may be issues that are difficult to discuss, yet relevant to the task at hand. If the group avoids the important questions it is important that the team leader address the issues. He/she may preface their statements by acknowledging that this subject makes you feel a little uncomfortable, but that it needs to be addressed. In doing so the topic will get the coverage needed, while bringing the issue to light in a respectful manner.

Culture and life experiences have a great influence on how individuals react to feedback. If an open environment is maintained these issues can be brought up and examined in order to best address the individual in a respectful manner. The potential consequences of not respecting the cultural norms can lead to a less effective team atmosphere.

In order to best address the issues of diversity it is important that a team sets up a process to allow safe and open communication that can be done in a respectful manner. A team contract is an excellent way to set up the rules for such discussions, especially when dealing with sensitive issues related to diversity. Every individual is responsible for their own adherence to the terms of the contract, as well as all group members present.

Managing Diversity
A team leader must think about diversity as diversity of ideas and experience, not just race and gender. A leader needs to recognize the diversity of each team member and achieve unity of common goals without destroying the uniqueness of any person. The team leader must do this within the scope of the organization’s resources relative to the growth of the team member.

Most problems in the work place are not that people cannot do their jobs. Rather it is that people cannot get along with others. The team leader should make efforts in effectively training soft skills. This includes such subjects as diversity, communication and people skills that allow people to understand each other and develop good team skills. Every team member must not only be able to understand and work with all the other team members, but they must also want to. Embracing diversity is the first step to managing a truly diverse team. In order to facilitate this, team leaders should consider the following:

 * Develop an atmosphere in which it is safe for all employees to ask for help. People should not be viewed as weak if they ask for help. Joining weakness with strengths to get a goal or objective accomplished is one aspect of building great teams. One person’s weakness should be another person’s strength.
 * Actively seek information from people from a variety of backgrounds and cultures in order to develop a broad picture.
 * Include everyone on the problem solving and decision making process.
 * Include people who are different than you in informal gatherings such as lunch, coffee breaks and spur of the moment meetings.
 * Create a team spirit in of which every member feels a part.

A team leader enables the other members to be innovative as well as self-directed within the capacity of individual assignments and allows them to learn from their own, as well as others’ successes, mistakes and failures. It is important to assure that each individual on the team has the opportunity to make the maximum contribution to the success of the team by doing the type of work for which s/he has the greatest opportunity for productivity and achievement.

Leaders have the task of using the other team members’ diverse gifts, abilities, and skills to achieve the common goal without the unintended consequence of conforming to the characteristics the others on the team. This requires active management by the leader to insure that diverse followers show respect and acceptance of the followers that are different in one way or another.

If team members do not accept others for what they are, they will be unable to use the abilities of each team member to fill in their own weak areas. Hence, the team effort develops knowledge and skill gaps that often lead to failure. Their only goal becomes the ones on their personal agendas while ignoring the needs of the team and the organization. Creating an environment that encourages diversity enables team members to accept every individual on the team and helps them realize that it takes a variety of people to become the best. This kind of environment also enforces the need to rely on everyone within the team, no matter how different another person may be. These characteristics and experiences make a worker unique. Diversity occurs when the whole team sees all these unique characteristics, and realizes that workers are more valuable because of their differences.

Stereotyping
Stereotypes are beliefs that all members of specific groups share similar traits and are likely to behave in the same way. Stereotypes create categories and then fit individuals into them. In some respects, this is a useful adaptation to the current environment, but in other cases, conclusions can be made that are detrimental to the understanding of people and to the dynamics of a team. Individuals never conform to an exact stereotype, given that individual differences outweigh similarities with others in a group, and subsequently, people on a team may use limited personal experience or perceptions of others to guide their interactions. Stereotypes are based on a variety of qualifications including gender, race, language, finances, religion and sexual preference.

Oftentimes people believe that males in business are good leaders, computer-savvy, unorganized, problem-solvers, etc. Females are often perceived as organized, record-keepers and relationship-oriented. In addition, there are some professions that are more stereotypically male and some that are more stereotypically female. Secretaries are typically thought to be female, as are nurses, flight attendants and often other supportive roles. Managers, doctors and pilots are typically thought to be male jobs. If a female is in a position of authority, her actions are often more heavily critiqued as unreasonable or unkind than her male counterpart behaving in the same way. Managers can avoid this stereotype by providing leadership opportunities to employees of both genders.

Race is another area where stereotyping can easily influence a group dynamic. Some races are considered high achievers, while other races are labeled as unmotivated. People of Asian or Indian descent are often seen as hardworking, intelligent, and technical, while people of Polynesian, American Indian and Hispanic descent are often viewed as lazy, unmotivated, and sometimes of below average intelligence. African American workers are sometimes considered confrontational and aggressive in contrast to their Asian peers. Language barriers can also be a catalyst to stereotyping. In America, a person who does not yet have a full grasp on the English language is often seen as unintelligent or inferior, when in fact they can be highly trained or skilled workers. Managers should monitor progress of all team players and concentrate on individual strengths and weaknesses rather than those perceived of the race they belong to.

Stereotyping associated with class differences can create an unsuccessful team dynamic as well. People in a lower socioeconomic class are often seen as lazy, unintelligent, and unrefined, whereas folks in a higher socioeconomic class are seen as educated, bright, motivated and polite. People may also be grouped and stereotyped by religion. Jews are often seen as frugal and business-minded; Muslims are sometimes labeled as extreme. Catholics may be labeled as traditional, while Evangelicals are seen as progressive. On a team, these differences can lead to dividing lines. This may be avoided by assigning tasks to subgroups that cross barriers, allowing people to form working relationships.

Sexual preference can also lead to harmful group stereotyping. Depending on the industry, gay men or women have more credibility. Gay men are seen as artistic, fashion-conscious and tasteful, while gay women are taken more seriously than straight women in the mechanical or construction industries. This is probably a result of more traditionally feminine/masculine traits being exhibited.

These stereotypes are harmful in groups for several reasons. A person may be misunderstood early in an interaction. Contributions may be limited and specific strengths or talents may be overlooked because they do not seem prominent in the given stereotypical category. On the other hand, poor performance can be overlooked in an individual because they belong to a stereotypically desirable group. Finally, by allowing stereotypes to govern groups we create natural divisions within the group, where ultimately a common goal should be established. Managers can combat this by mixing teams, creating smaller mixed teams for subtasks, monitoring all team members’ progress and allowing individuals to volunteer for roles rather than being cast into their default role as defined by their stereotypical category.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Managing Groups and Teams/Diversity


text:
User:Eagle 101~enwikibooks

Hello, I am new to wikibooks, but am not new to wiki's in general. I have edited on wikipedia for the last 5 months under the same username. (Eagle_101)

title: User:Eagle 101~enwikibooks


text:
Talk:Managing Groups and Teams/Question Page

Hi I'm here. This is TJ

--155.97.75.64 03:24, 7 June 2006 (UTC)


text:
Adventist Youth Honors Answer Book/Vocational/Communications - Advanced

1. Have the Communications Honor
The answers for the Communications honor can be found in the Vocational chapter of this wikibook.


text:
Talk:Orthopaedic Surgery/Introduction

I am planning to revamp the introduction page for this book. The present introduction is lengthy, inadequate and unappealing. I think the introduction must be divided into two sections, one for the wiki nature of the book and the other to orthopaedic surgery. I plan to start on this if there is no response to this message in three days time.

BDB 04:36, 7 June 2006 (UTC)

 * Presently I am in the process of rewriting the introduction for this wikibook. Will be taking more time than I thought it would require. Please feel frre to make your contribution in the meanwhile. BDB 08:29, 13 June 2006 (UTC)
 * Finally managed to revamp the introduction. Though it is complete it is not enough, I think. It could do with some more references. and the wikibook part needs some working on.BDB 13:52, 17 June 2006 (UTC)

title: Talk:Orthopaedic Surgery/Introduction


text:
Basic Physics of Nuclear Medicine/Chapter Review

Chapter Review: Atomic & Nuclear Structure

 * The atom consists of two components – a nucleus (positively charged) and an electron cloud (negatively charged);
 * The radius of the nucleus is about 10,000 times smaller than that of the atom;
 * The nucleus can have two component particles – neutrons (no charge) and protons (positively charged) – collectively called nucleons;
 * The mass of a proton is about equal to that of a neutron – and is about 1,840 times that of an electron;
 * The number of protons equals the number of electrons in an isolated atom;
 * The Atomic Number specifies the number of protons in a nucleus;
 * The Mass Number specifies the number of nucleons in a nucleus;
 * Isotopes of elements have the same atomic number but different mass numbers;
 * Isotopes are classified by specifying the element's chemical symbol preceded by a superscript giving the mass number and a subscript giving the atomic number;
 * The atomic mass unit is defined as 1/12th the mass of the stable, most commonly occurring isotope of carbon (i.e. C-12);
 * Binding energy is the energy which holds the nucleons together in a nucleus and is measured in electron volts (eV);
 * To combat the effect of the increase in electrostatic repulsion as the number of protons increases, the number of neutrons increases more rapidly – giving rise to the Nuclear Stability Curve;
 * There are ~2450 isotopes of ~100 elements and the unstable isotopes lie above or below the Nuclear Stability Curve;
 * Unstable isotopes attempt to reach the stability curve by splitting into fragments (fission) or by emitting particles/energy (radioactivity);
 * Unstable isotopes <=> radioactive isotopes <=> radioisotopes <=> radionuclides;
 * ~300 of the ~2450 isotopes are found in nature – the rest are produced artificially.

Chapter Review: Radioactive Decay

 * Fission: Some heavy nuclei decay by splitting into 2 or 3 fragments plus some neutrons. These fragments form new nuclei which are usually radioactive;
 * Alpha Decay: Two protons and two neutrons leave the nucleus together in an assembly known as an alpha-particle;
 * An alpha-particle is a He-4 nucleus;
 * Beta Decay – Electron Emission: Certain nuclei with an excess of neutrons may reach stability by converting a neutron into a proton with the emission of a beta-minus particle;
 * A beta-minus particle is an electron;
 * Beta Decay – Positron Emission: When the number of protons in a nucleus is in excess, the nucleus may reach stability by converting a proton into a neutron with the emission of a beta-plus particle;
 * A beta-plus particle is a positron;
 * Positrons annihilate with electrons to produce two back-to-back gamma-rays;
 * Beta Decay – Electron Capture: An inner orbital electron is attracted into the nucleus where it combines with a proton to form a neutron;
 * Electron capture is also known as K-capture;
 * Following electron capture, the excited nucleus may give off some gamma-rays. In addition, as the vacant electron site is filled, an X-ray is emitted;
 * Gamma Decay – Isomeric Transition: A nucleus in an excited state may reach its ground state by the emission of a gamma-ray;
 * A gamma-ray is an electromagnetic photon of high energy;
 * Gamma Decay – Internal Conversion: the excitation energy of an excited nucleus is given to an atomic electron.

Chapter Review: The Radioactive Decay Law

 * The radioactive decay law in equation form;
 * Radioactivity is the number of radioactive decays per unit time;
 * The decay constant is defined as the fraction of the initial number of radioactive nuclei which decay in unit time;
 * Half Life: The time taken for the number of radioactive nuclei in the sample to reduce by a factor of two;
 * Half Life = (0.693)/(Decay Constant);
 * The SI Unit of radioactivity is the becquerel (Bq)
 * 1 Bq = one radioactive decay per second;
 * The traditional unit of radioactivity is the curie (Ci);
 * 1 Ci = 3.7 x 1010 radioactive decays per second.

= = Chapter Review: Units of Radiation Measurement ==

 * Exposure expresses the intensity of an X- or gamma-ray beam;
 * The SI unit of exposure is the coulomb per kilogram (C/kg);
 * 1 C/kg = The quantity of X- or gamma-rays such that the associated electrons emitted per kg of air at STP produce in air ions carrying 1 coulomb of electric charge;
 * The traditional unit of exposure is the roentgen (R);
 * 1 R = The quantity of X- or gamma-rays such that the associated electrons emitted per kg of air at STP produce in air ions carrying 2.58 x 10-4 coulombs of electric charge;
 * The exposure rate is the exposure per unit time, e.g. C/kg/s;
 * Absorbed dose is the radiation energy absorbed per unit mass of absorbing material;
 * The SI unit of absorbed dose is the gray (Gy);
 * 1 Gy = The absorption of 1 joule of radiation energy per kilogram of material;
 * The traditional unit of absorbed dose is the rad;
 * 1 rad = The absorption of 10-2 joules of radiation energy per kilogram of material;
 * The Specific Gamma-Ray Constant expresses the exposure rate produced by the gamma-rays from a radioisotope;
 * The Specific Gamma-Ray Constant is expressed in SI units in C/kg/s/Bq at 1 m;
 * Exposure from an X- or gamma-ray source follows the Inverse Square Law and decreases with the square of the distance from the source.

Chapter Review: Interaction of Radiation with Matter

 * Alpha-Particles:
 * exert considerable electrostatic attraction on the outer orbital electrons of atoms near which they pass and cause ionisations;
 * travel in straight lines – except for rare direct collisions with nuclei of atoms in their path;
 * energy is always discrete.
 * Beta-Minus Particles:
 * attracted by nuclei and repelled by electron clouds as they pass through matter and cause ionisations;
 * have a tortuous path;
 * have a range of energies;
 * range of energies results because two particles are emitted – a beta-particle and a neutrino.
 * Gamma-Rays:
 * energy is always discrete;
 * have many modes of interaction with matter;
 * important interactions for nuclear medicine imaging (and radiography) are the Photoelectric Effect and the Compton Effect.
 * Photoelectric Effect:
 * when a gamma-ray collides with an orbital electron, it may transfer all its energy to the electron and cease to exist;
 * the electron can leave the atom with a kinetic energy equal to the energy of the gamma-ray less the orbital binding energy;
 * a positive ion is formed when the electron leaves the atom;
 * the electron is called a photoelectron;
 * the photoelectron can cause further ionisations;
 * subsequent X-ray emission as the orbital vacancy is filled.
 * Compton Effect:
 * A gamma-ray may transfer only part of its energy to a valence electron which is essentially free; ** gives rise to a scattered gamma-ray;
 * is sometimes called Compton Scatter;
 * a positive ion results;
 * Attenuation is term used to describe both absorption and scattering of radiation.

Chapter Review: Attenuation of Gamma-Rays

 * Attenuation of a narrow-beam of gamma-rays increases as the thickness, the density and the atomic number of the absorber increases;
 * Attenuation of a narrow-beam of gamma-rays decreases as the energy of the gamma-rays increases;
 * Attenuation of a narrow beam is described by an equation;
 * the Linear Attenuation Coefficient is defined as the fraction of the incident intensity absorbed in a unit distance of the absorber;
 * Linear attenuation coefficients are usually expressed in units of cm-1;
 * the Half Value Layer is the thickness of absorber required to reduce the intensity of a radiation beam by a factor of 2;
 * Half Value Layer = (0.693)/(Linear Attenuation Coefficient);
 * the Mass Attenuation Coefficient is given by the linear attenuation coefficient divided by the density of the absorber;
 * Mass attenuation coefficients are usually expressed in units of cm2 g-1.

Chapter Review: Gas-Filled Detectors

 * Gas-filled detectors include the ionisation chamber, the proportional counter and the Geiger counter;
 * They operate on the basis of ionisation of gas atoms by the incident radiation, where the positive ions and electrons produced are collected by electrodes;
 * An ion pair is the term used to describe a positive ion and an electron;
 * The operation of gas-filled detectors is critically dependent on the magnitude of the applied dc voltage;
 * The output voltage of an ionisation chamber can be calculated on the basis of the capacitance of the chamber;
 * A very sensitive amplifier is required to measure voltage pulses produced by an ionisation chamber;
 * The gas in ionisation chambers is usually air;
 * Ionisation chambers are typically used to measure radiation exposure (in a device called an Exposure Meter) and radioactivity (in a device called an Isotope Calibrator);
 * The total charge collected in a proportional counter may be up to 1000 times the charge produced initially by the radiation;
 * The initial ionisation triggers a complete gas breakdown in a Geiger counter;
 * The gas in a Geiger counter is usually an inert gas;
 * The gas breakdown must be stopped in order to prepare the Geiger counter for a new event by a process called quenching;
 * Two types of quenching are possible: electronic quenching and the use of a quenching gas;
 * Geiger counters suffer from dead time, a small period of time following the gas breakdown when the counter is inoperative;
 * The true count rate can be determined from the actual count rate and the dead time using an equation;
 * The value of the applied dc voltage in a Geiger counter is critical, but high stability is not required.

Chapter Review: Scintillation Detectors

 * NaI(Tl) is a scintillation crystal widely used in nuclear medicine;
 * The crystal is coupled to a photomultiplier tube to generate a voltage pulse representing the energy deposited in the crystal by the radiation;
 * A very sensitive amplifier is needed to measure such voltage pulses;
 * The voltages pulses range in amplitude depending on how the radiation interacts with the crystal, i.e. the pulses form a spectrum whose shape depends on the interaction mechanisms involved, e.g. for medium-energy gamma-rays used in in-vivo nuclear medicine: the Compton effect and the Photoelectric effect;
 * A Gamma-Ray Energy Spectrum for a medium-energy, monoenergetic gamma-ray emitter consists (simply) of a Compton Smear and a Photopeak;
 * Pulse Height Analysis is used to discriminate the amplitude of voltage pulses;
 * A pulse height analyser (PHA) consists of a lower level discriminator (which passes voltage pulses which are than its setting) and an upper level discriminator (which passes voltage pulses lower than its setting);
 * The result is a variable width window which can be placed anywhere along a spectrum, or used to scan a spectrum;
 * A single channel analyser (SCA) consists of a single PHA with a scaler and a ratemeter;
 * A multi-channel analyser (MCA) is a computer-controlled device which can acquire data from many windows simultaneously.

Chapter Review: Nuclear Medicine Imaging Systems

 * A gamma camera consists of a large diameter (25-40 cm) NaI(Tl) crystal, ~1 cm thick;
 * The crystal is viewed by an array of 37-91 PM tubes;
 * PM tubes signals are processed by a position circuit which generates +/- X and +/- Y signals;
 * These position signals are summed to form a Z signal which is fed to a pulse height analyser;
 * The +/- X, +/- Y and discriminated Z signals are sent to a computer for digital image processing;
 * A collimator is used to improve the spatial resolution of a gamma-camera;
 * Collimators typically consist of a Pb plate containing a large number of small holes;
 * The most common type is a parallel multi-hole collimator;
 * The most resolvable area is directly in front of a collimator;
 * Parallel-hole collimators vary in terms of the number of holes, the hole diameter, the length of each hole and the septum thickness – the combination of which affect the sensitivity and spatial resolution of the imaging system;
 * Other types include the diverging-hole collimator (which generates minified images), the converging-hole collimator (which generates magnified images) and the pin-hole collimator (which generates magnified inverted images);
 * Conventional imaging with a gamma camera is referred to as Planar Imaging, i.e. a 2D image portraying a 3D object giving superimposed details and no depth information;
 * Single Photon Emission Computed Tomography (SPECT) produces images of slices through the body;
 * SPECT uses a gamma camera to record images at a series of angles around the patient;
 * The resultant data can be processed using Filtered Back Projection and Iterative Reconstruction;
 * SPECT gamma-cameras can have one, two or three camera heads;
 * Positron Emission Tomography (PET) also produces images of slices through the body;
 * PET exploits the positron annihilation process where two 0.51 MeV back-to-back gamma-rays are produced;
 * If these gamma-rays are detected, their origin will lie on a line joining two of the detectors of the ring of detectors which encircles the patient;
 * A Time-of-Flight method can be used to localise their origin;
 * PET systems require on-site or nearby cyclotron to produce short-lived radioisotopes, such as C-11, N-13, O-15 and F-18.

Chapter Review: Production of Radioisotopes

 * Naturally-occurring radioisotopes generally have long half lives and belong to relatively heavy elements – and are therefore unsuitable for medical diagnostic applications;
 * Medical diagnostic radioisotopes are generally produced artificially;
 * The fission process can be exploited so that radioisotopes of interest can be separated chemically from fission products;
 * A cyclotron can be used to accelerate charged particles up to high energies so that they to collide into a target of the material to be activated;
 * A radioisotope generator is generally used in hospitals to produce short-lived radioisotopes;
 * A technetium-99m generator consists of an alumina column containing Mo-99, which decays into Tc-99m;
 * Saline is passed through the generator to elute the Tc-99m – the resulting solution is called sodium pertechnetate;
 * Both positive pressure and negative pressure generators are in use;
 * An isotope calibrator is needed when a Tc-99m generator is used in order to determine the activity for preparation of patient doses and to test whether any Mo-99 is present in the collected solution.

Exercise Questions
1. Discuss the process of radioactive decay from the perspective of the nuclear stability curve.

2. Describe in detail FOUR common forms of radioactive decay.

3. Give the equation which expresses the Radioactive Decay Law, and explain the meaning of each of its terms.

4. Define each of the following:

 * (a) Half life;
 * (b) Decay Constant;
 * (c) Becquerel.

5. A sample of radioactive substance is found to have an activity of 100 kBq. Its radioactivity is measured again 82 days later and is found to be 15 kBq. Calculate:

 * (a) the half-life;
 * (b) the decay constant.

6. Define each of the following radiation units:

 * (a) Roentgen;
 * (b) Becquerel;
 * (c) Gray.

7. Estimate the exposure rate at 1 metre from a 100 MBq source of radioactivity which has a Specific Gamma Ray Constant of 50 mR per hour per MBq at 1 cm.

8. Briefly describe the basic principle of operation of gas-filled radiation detectors.

9. Illustrate using a graph how the magnitude of the voltage pulses from a gas-filled radiation detector varies with applied voltage and identify on the graph the regions associated with the operation of Ionisation Chambers and the Geiger Counters.

10. Describe the construction and principles of operation of a scintillation spectrometer.

11. Discuss the components of the energy spectrum from a monoenergetic, medium energy gamma- emitting radioisotope obtained using a scintillation spectrometer on the basis of how the gamma-rays interact with the scintillation crystal.

12. Describe the construction and principles of operation of a Gamma Camera.

13. Compare features of three types of collimator which can be used with a Gamma Camera.


text:
User:AndyD

Note
Please do not edit this page in any way unless you are authorised to do so or are familiar with the terms under which user pages might usually be edited.

Interests and Projects

 * Wrote Bouncing Ball Animation
 * Wrote Lip-Sync with Shape Keys
 * Wrote Lattices in Blender
 * Added step-by-step section to existing Shape Keys page

title: User:AndyD


text:
BLL German/A1/Lesson 6

An outline

Text: Thomas and Maria are now walking to the city. On the way, they meet Julia.

Thomas: Hallo Julia! Kennst du schon Maria? Sie kommt aus Madrid. Julia: Nein. Freut mich, Maria. Ich bin Julia. Maria: Gleichfalls, Julia. Was macht ihr jetzt? Thomas: Wir gehen etwas essen. Julia: Geht ihr in die Mensa? Thomas: Nein, in die Stadt. Kommst du auch mit? Julia: Ja, ich komme mit.

Grammar: wir & ihr Formen

title: BLL German/A1/Lesson 6


text:
William Shakespeare's Works/Sonnets

The Youth and the Lady
The author's sonnets are written for two subjects: a young man, and the narrator's beloved. In the first of these cases, the narrator advises his young follower on how to attract women, while simultaneously declaring his own affection for the young lad. Modern scholars have claimed that their relationship borders on pederasty. However, none of his sonnets have directly declared this intent.

Sonnet structure
Before the arrival of Shakespeare, most poets followed the form of what is known as the Petrarchan sonnet:

A

B

B

A

A

B

B

A

C

D

E

C

D

E

The last six lines could either come in the above form (C-D-E-C-D-E) or in the form of (C-D-C-C-D-C). This was the standard form for nearly three hundred years. However, Shakespeare revolutionized the sonnet with the creation of his own form, which would soon bear his name:

A

B

A

B

C

D

C

D

E

F

E

F

G

G

Guide to the sonnets

 * /Sonnets 1-10/
 * /Sonnets 11-20/
 * /Sonnets 21-30/
 * /Sonnets 31-40/
 * /Sonnets 41-50/
 * /Sonnets 51-60/
 * /Sonnets 61-70/
 * /Sonnets 71-80/
 * /Sonnets 81-90/
 * /Sonnets 91-100/
 * /Sonnets 101-110/
 * /Sonnets 111-120/
 * /Sonnets 121-130/
 * /Sonnets 131-140/
 * /Sonnets 141-150/
 * /Sonnets 151-154/

title: William Shakespeare's Works/Sonnets


text:
User talk:KXL

You have been "dumping" (to use your own phraseology) some pages on The Complete Peanuts Annotations that were previously on Wikipedia. Wikibooks is, however, for textbooks, and the pages you have added do not appear to be textbooks. I will leave things a short while to give you a chance to put me right if I have misunderstood the situation, otherwise these pages will be deleted shortly, Jguk 12:41, 7 June 2006 (UTC)

 * I'm afraid what you've been told at Wikipedia is wrong. Wikibooks is a separate Wikimedia project. This means we are independent of Wikipedia, and Wikipedia is independent of us, although there are, of course, many linkages and similarities as you'd expect of sister projects. Just as Wikipedia has its own inclusion criteria, so Wikibooks has its own inclusion criteria too - and it does not follow that just because something does not meet Wikipedia's inclusion criteria it must necessarily meet the inclusion criteria of another Wikimedia project.

 * Wikibooks' inclusion criteria is for textbooks. This can include annotated texts if they are suitable for study of the books as part of, say, a course in English Literature. But they ought to have the feel of a textbook, rather than just be a series of what are essentially footnotes. It is somewhat unfortunate that many Wikipedians are unaware of our inclusion criteria and therefore end up making misleading suggestions where there is book like material added to Wikipedia which is outside its scope.

 * On the face of it, your additions are not those of a textbook. Now, it may be your intention to develop these pages further so that they are part of a textbook - in which case there would be no objection to them staying here and forming part of that textbook. However, if that is not your intention, then the content unfortunately does not belong here and will therefore be deleted. All the best, Jguk 12:51, 7 June 2006 (UTC)

OK. Good luck in finding a suitable home for it. Incidentally, I think the best "annotated text" we have is Muggles' Guide to Harry Potter. If you ever are thinking of providing an annotated text textbook, that would be a good guide to follow. Kind regards, Jguk 13:05, 7 June 2006 (UTC)

title: User talk:KXL


text:
User talk:IvanLanin

''I'm from Indonesian Wikipedia. Please see my profile or talk to me there. Thanks!''

title: User talk:IvanLanin


text:
Talk:Managing Groups and Teams/Motivation

Hi there - Any chance you can move everything but the title of the chapter out of the front page? Just to keep things uncluttered... Gerardo.ok 13:36, 7 June 2006 (UTC)


text:
RC Airplane/Balancing the plane

When a plane has been constructed or assembled, it needs to be balanced before you fly it. It should not be nose or tail heavy. With the plane fully assembled but with no fuel in the tank, pick the plane up by the wing tips and ensure it does not tip forward or backwards.

Many planes identify their center of gravity position. This is the position on the wings where the balance point should be measured from. If the balance point is not identified in the build manual or on the plan sheet, a general rule-of-thumb is to balance the plane 25% of the "mean aerodynamic chord" (the average distance from the leading edge to the trailing edge - usually the thickest part of the wing).

If the plane is not balanced properly, there are a number of options. Firstly, if the location of the wing can be moved forward or backwards, that is usually a good idea. If the plane tips forward, move the wing forward. If the plane tips towards the tail, move the wing towards the tail. Basically move the wing in the heavy direction.

For planes which use wooden dowels placed through the fuselage and elastic bands to hold the wing on, a suggested way to find the location where the dowels should be placed is to place them temporarily under the fuselage and used an elastic band from one side of the dowel to the other over the top of the fuselage. With the two dowels strapped on in this fashion, the wing can then be attached in the manner that it will eventually be attached in flight. The dowels (and the wing) can then be slid forwards or backwards until a good balancing location is reached.

title: RC Airplane/Balancing the plane


text:
RC Airplane/Building SPADs

The SPAD or Simple Plastic Airplane Design is the notion of building airplanes from plastic parts commonly found at DIY and home improvement stores.

SPADs are commonly made from a few sets of materials

 * Coroplast
 * PVC Pipe
 * Yardsticks
 * Plastic cutting boards
 * Zip Ties
 * Dowels

SPAD Plans
Many SPAD plans are freely available. Some of the more common plan download sites can be found at:

 * SPAD Dawg's
 * SPAD to the Bone

The SPAD Community
The people who build and fly SPADs have their own SPAD community.

title: RC Airplane/Building SPADs


text:
WebObjects/Web Applications/Deployment/Java Monitor

Troubleshooting
If JavaMonitor did not start on your fresh install of WebObjects, check out the WOTaskd Didn't Start question in the troubleshooting section.


text:
RC Airplane/Coroplast

=Coroplast= Coroplast is used in the making of plastic signs. In much of the SPAD world, coroplast is usually shortened to "coro".

Coro is the plastic equivalent of corrugated cardboard. It consists of two parallel plastic sheets with vertical spars between them. The channels created by these spars are termed 'flutes'. When working with coro, always ensure that you are thinking about the direction in which the flutes travel.

Coro usually comes in two varieties of thickness.
 * 4mm
 * 2mm

The 4mm seems to be more prevalent than the 2mm.

Cutting Coroplast
Coro can be cut using a sharp knife such as a new bladed box cutter. It is strongly recommended that a guide be used to ensure that the blade does not deviate from any desired straight line. Making a few scores with the blade rather than a single deep cut seems to give the best results and best accuracy.

Cutting in the same direction as the flutes is easiest, cutting against the direction of the flutes is also not that difficult. Cutting with the flutes can be easily done with a hand held flute knife such as a Coro-Claw. The most challenging direction is one that is neither parallel or perpendicular to the flutes but rather at an angle. The texture of the cut keeps changing. Slow and steady seems to offer the best results.

Flashing Coroplast
In order to glue one piece of Coro to another, CA glue may be used. Unfortunately, it is not enough just to apply some glue to the parts to be bonded. By nature, the plastic used for making Coro does not bond well unless its surface is first "activated". A common technique for achieving this is called 'flashing'. This involves passing a flame over the surface for just a moment, being careful not to melt the surface. A hand-held torch seems to work well for this task and can be purchased for under $15 from your local hardware store. Test your technique on a scrap piece first. Water should not form droplets, but a thin film on properly activated Coro.

Pinning Coroplast
The flutes of Coroplast can be attached to make a column or free standing sign by using a Coro Pin. The pin acts as a huge bobby pin and goes in the flutes of two sides of Coroplast to attach them.

Suppliers

 * Regal Plastics - Retail supplier in TX, OK and LA.

title: RC Airplane/Coroplast


text:
RC Airplane/Yardsticks

Yardsticks are used as the spars/struts in the interior of wings. When choosing yardsticks, try and find ones which are as straight as possible. Also pay attention to the direction of the grain of the wood. Ideally it should be along the short direction (up and down if the stick is on its edge).

Yardsticks can be found at home improvement/DIY stores.
 * ACE Hardware

Some stores that apparently do not carry yardsticks include:
 * Lowe's

title: RC Airplane/Yardsticks


text:
RC Airplane/Zip Ties

Plastic ZIP Ties (as found for tying cables together) can be used to hold various components in place such as servos and push rod sleeves.

title: RC Airplane/Zip Ties


text:
RC Airplane/Dowels

Wooden dowels of about 1/4" in diameter make great anchors for elastic bands used to strap the wings in place.

On occasion, it can be found that the location of the dowel to achieve a good CG would place it straight through the fuel bottle or some other central component. A solution to this is to use wire on the underside of the plane.

This picture illustrates coat hanger wire bent appropriately:

Here is an example of the wire being used to hold down the elastic bands to hold the plane to the wing:

title: RC Airplane/Dowels


text:
RC Airplane/PVC Pipe

PVC Pipe is commonly used for fuselage construction. The desired size is the 2 1/4" and 2 1/2" square variety.

The square 2 1/2" inch downspout pipe (AKA American Gutter Pipe) is used in the Debonair plans and it can be found at Sutherlands Lumber stores in the Texas and Oklahoma area. It has also been found at Do It Best hardware stores. The 10' length of white downspout is made by Genova Building Products and the Genova Model Number is RW200.

title: RC Airplane/PVC Pipe


text:
Horticulture/Tomato

Tomatoes are in many regions among the most popular fruits grown in gardens, because with most varieties freshness is a major factor in the quality of harvested fruit.

Growing Conditions
Tomato plants need acidic (5.0 to 6.0 pH) soil, a balance between the three primary fertilizer nutrients, and thrive in warm weather. Inexpensive ways to naturally increase soil acidity include using pine needles as mulch, and mixing either used coffee grounds or sawdust into the soil. Pine needles (and the soil under pine trees) are very acidic, and though used coffee grounds are not very acidic, they and sawdust cause a chemical change in the soil, lowering its pH. Fresh coffee grounds or a 4:1 solution of water and coffee can be used for a quick, direct boost in acidity. Tomatoes do not need high calcium content in order to produce good fruits.

In temperate climates, tomatoes are generally started from seed indoors, then planted out after the last frost date. Tomatoes are planted deeply in the soil, often burying the plant up to just below its top set of leaves, as it roots freely off the stem. If staked, trellised, or caged (methods of supporting the weight of vining plants, allowing them to devote more energy into growing fruit), tomato plants can be grown much closer together than the three feet usually recommended.

While tomato plants do best with eight or more hours of direct sunlight, they may do better if shaded during noontime sun if the temperature is above ninety degrees. Some gardeners will actually throw fine cloth over the plants around noon on very hot days. Indeterminate plants require at least twenty gallons of soil in order to grow in a container; it's better to use determinate varieties for containers, instead.

In each tomato plant, there are about 2 to 3kg when the tomato plant has finished growing. Tomatoes tend to grow faster and produce more fruit when companion planting. Marigolds repel aphids and grow well with tomatoes, and Basil both repels insects (even mosquitoes) and improves fruit flavor. Other companion plants for tomatoes are asparagus, onion/garlic/chives, nasturtium, rose, and parsley. Tomato plants are themselves good companion plants for chili peppers, helping shade their fruit.

Varieties

 * Beefsteak VFN (a common hybrid resistant to Verticillium, Fusarium, and Nematodes)
 * Big Boy (a very common determinate garden cultivar in the United States)
 * Black Krim (a purple-and-red variety from Crimea)
 * Brandywine (a pink, indeterminate beefsteak type with a considerable number of substrains)
 * Burpee VF (an early attempt at disease resistance in a commercial tomato)
 * Early Girl (an early-maturing indeterminate)
 * Gardener's Delight (a smaller English variety)
 * Jet Star Hybrid ( low acid, big yield, large globe shape fruit)
 * Juliet (a grape tomato developed as a substitute for the rare Santa F1)
 * Marmande (a heavily ridged variety from southern France; similar to a small beefsteak and available commercially in the US as UglyRipe)
 * Moneymaker (an English greenhouse variety)
 * Mortgage Lifter (a popular heirloom beefsteak known for gigantic fruit)
 * Patio (bred specifically for container gardens)
 * Roma VF (a plum tomato common in supermarkets)
 * Rutgers (an heirloom commercial variety)
 * San Marzano (a plum tomato popular in Italy)
 * Santa F1 (a closely guarded Chinese grape tomato cultivar popular in the USA and parts of southeast Asia)
 * Sweet 100 (a very prolific, indeterminate cherry tomato)
 * Yellow Pear (a yellow, pear-shaped heirloom variety)

Early Spring
Tomatoes grow best in a deep, rich soil, so preparing the bed for this is key.

Seeds are usually planted indoors 4-8 weeks before the last frost date.

Trellising or cages should be put in before the tomatoes are planted.

Summer
Consistent irrigation is key, because inconsistent irrigation can lead to cracking. Irrigation should be to the soil, rather than using sprinklers.

Fall Cleanup
Just before the first frost, it's a good idea to pick the last green tomatoes (which can be used in many recipes, and can be pickled much like cucumbers), as they can be damaged by cold. All vines should be removed from the field (roots and all) to help manage any disease organisms. Seeds will sprout in cold compost piles, so heat composting should be used if possible. be sure to make clean as possible.

Propagation
Tomatoes are almost always propagated by seed but some success has been had with stem cuttings.

Grafting
Tube grafting should be carried out when the seedlings have two to four true leaves and the stems are 1.5 to 2 millimeters in diameter (Figure 3). For proper healing to take place, the vascular tissue in the rootstock and scion must align so that their tissues can easily grow together, forming a strong union for water and nutrient uptake. Again, an essential component for grafting success is to use rootstock and scion plants that have similar stem diameters. Grafting should take place when there is little water stress upon the plants. Early in the morning or just after dark are excellent times to graft as transpiration has typically slowed to reduced levels. Additionally, the grafting process should be carried out indoors or under some sort of shading device. If daytime grafting is essential due to timing and labor concerns, move the plants to a shady area in the morning before transpiration increases to prevent unwanted water stress during the process.

Harvesting
Tomatoes should be harvested as soon as ripe. Most varieties will continue to ripen once picked.

Many varieties have delicate fruits, and should not be stacked too high in the basket.

Pests and Diseases
Tomato cultivars vary widely in their resistance to disease. Modern hybrids focus on improving disease resistance over the heirloom plants. One common tomato disease is tobacco mosaic virus. Various forms of mildew and blight are also common tomato afflictions, which is why tomato varieties are usually marked with letters like VFN, which refers to disease resistance to verticillium wilt, fusarium fungus, and nematodes.

Some common tomato pests are cutworms, tomato hornworms, aphids, cabbage loopers, whiteflies, tomato fruitworms, flea beetles, and Colorado potato beetles and moth lava.

Transplanted tomatoes may begin to show yellow leaves at the base. According to hothouse tomato pioneer, Dan Busch, "With your leaves turning yellow, the tomato plant needs to be fertilized. The fertilizer that you need to use needs to be well balanced, meaning 20-20-20, and if you do not want to use this kind of fertilizer, use blood meal and fish emulsions. This will give you a good source of nitrogen, then you will need to add phosphorus (rock phosphate or super phosphate). Slow growing plants are a sure sign of low phosphorus. Be sure to read the instructions on the blood meal and fish emulsion because it is easy to over fertilize. The real issue here is the nutrition. The yellowing of the leaves is not uncommon with a new transplant, because any nutrition is gone by the time you take it home. If the plants are weak, this is an indication of low potassium. To get potassium in the soil you can add granite dust or wood ash. Call around to local garden centers to find these items.

Viral diseases

 * Tobacco Mosaic Virus (TMV)

Arthropod Pests
To prevent cutworms, tomato seedlings' most vicious predators, one can place an open-ended can so that it surrounds the plant, or wrap it with something like foil or paper, or simply brace its stem with popsicle sticks or toothpicks, all of which seem to deter this moth larva from wrapping around and cutting off the baby plant at its base or leaves.

Vertebrate Pests
Birds occasionally damage fruits by pecking. Chipmunks and rats may eat whole fruits.

White tail deer can be a serious problem in North America.

Yellow leaves on transplants
Transplanted tomatoes may begin to show yellow leaves at the base. According to hothouse tomato pioneer, Dan Busch, "With your leaves turning yellow, the tomato plant needs to be fertilized. The fertilizer that you need to use needs to be well balanced, meaning 20-20-20, and if you do not want to use this kind of fertilizer, use blood meal and fish emulsions. This will give you a good source of nitrogen, then you will need to add phosphorus (rock phosphate or super phosphate). Slow growing plants is a sure sign of low phosphorus. Be sure to read the instructions on the blood meal and fish emulsion because it is easy to over fertilize. The real issue here is the nutrition. The yellowing of the leaves is not uncommon with a new transplant, because any nutrition is gone by the time you take it home. If the plants are weak, this is an indication of low potassium. To get potassium in the soil you can add granite dust or wood ash. Call around to local garden centers to find these items.

Yellowing leaves can also be caused by either magnesium or sulfur deficiency, both of which can be treated by adding dissolved epsom salt or other forms of magnesium sulfate to the soil, and foliar feeding the plant with a mixture of two tablespoons epsom salts per gallon. Foliar treatment is reputed to work within 48 hours, but the soil does also need to be amended as a long-term fix.

title: Horticulture/Tomato


text:
Talk:Horticulture/Tomato

Transwikied "Cultivation and Uses"
The following is a snip from the version of the [wikipedia article on tomatoes as found on June 7, 2006, 5:35 GMT]. For information about the editors, please see the history page of that article.

>>> The tomato is now grown world-wide for its edible fruits, with thousands of cultivars having been selected with varying fruit types, and for optimum growth in differing growing conditions. Cultivated tomatoes vary in size from cherry tomatoes, about the same 1-2 cm size as the wild tomato, up to 'beefsteak' tomatoes 10 cm or more in diameter. The most widely grown commercial tomatoes tend to be in the 5-6 cm diameter range. Most cultivars produce red fruit, but a number of cultivars with yellow, orange, pink, purple, green, or white fruit are also available. Multicolored and striped fruit can also be quite striking. Tomatoes grown for canning are often elongated, 7-9 cm long and 4-5 cm diameter; these are known as plum tomatoes.

Tomatoes are one of the most common food groups in the United States. and along with zucchini have a reputation for outproducing the needs of the grower.

As in most sectors of agriculture, there is increasing demand in developed countries for organic tomatoes, as well as heirloom tomatoes to make up for flavor and texture faults in commercial tomatoes. Quite a few seed merchants and banks provide a large selection of heirloom seeds. Tomato seeds are occasionally organically produced as well, but only a small percentage of organic crop acreage is grown with organic seed.

Growing needs
Tomato plants can be easy to grow, producing a significant amount of fruit for a small amount of work, which is perhaps why 80% of American gardens include some kind of tomato. They can be raised from seeds by planting indoors eight weeks before it will be warm enough to plant outside, or they can be planted as purchased seedlings directly in the ground. Tomato plants need acidic (5.0 to 6.0 pH) soil, a balance between the three primary fertilizer nutrients, and thrive in warm weather. Inexpensive ways to naturally increase soil acidity include using pine needles as mulch, and mixing either used coffee grounds or sawdust into the soil. Pine needles (and the soil under pine trees) are very acidic, and though used coffee grounds are not very acidic, they and sawdust cause a chemical change in the soil, lowering its pH. Fresh coffee grounds, or a 4:1 dilution of water:coffee, can be used for a quick, direct acidity boost. To prevent cutworms, tomato seedlings' most vicious predators, one can place an open-ended can so that it surrounds the plant, or wrap it with something like foil or paper, or simply brace its stem with popsicle sticks or toothpicks, all of which seem to deter this moth larva from wrapping around and cutting off the baby plant at its base or leaves. Tomato plants can be grown much closer together than the standard 3' apart, if staked, trellised, or caged, all of which are methods of holding up vining plants to allow them to put more energy into growing fruit. Recent, peer-reviewed science suggests that red plastic mulch (sheets of plastic, dyed specific colors which reflect red and higher frequencies of light) increase fruit production by as much as 20%. While tomato plants do best with eight or more hours of direct sunlight, they may do better if shaded during noontime sun if the temperature is above ninety degrees. Some gardeners will actually throw fine cloth over the plants around noon on very hot days. Indeterminate plants require at least twenty gallons of soil in order to grow in a container; it's better to use determinate varieties for containers, instead. Tomatoes tend to grow faster and produce more fruit when companion planting. Marigolds repel aphids and grow well with tomatos, and Basil both repels insects (even mosquitos) and improves fruit flavor. Other companion plants for tomatoes are asparagus, onion/garlic/chives, nasturtium, rose, and parsley. Tomato plants are, themselves, good companion plants for chili peppers, helping shade their fruit.

Varieties and cultivars
There are a great many tomato varieties grown for various purposes. This section attempts a listing of some of the more common varieties. Heirloom varieties are becoming increasingly popular, particularly among home gardeners and organic producers, since they tend to produce more interesting and flavorful crops at the possible cost of some disease resistance. Hybrid plants remain common, however, since they tend to be heavier producers and sometimes combine unusual characteristics of heirloom tomatoes with the ruggedness of conventional commercial tomatoes.

Tomato varieties are roughly divided into several categories, based mostly on shape and size. "Slicing" or "globe" tomatoes are the usual tomatoes of commerce; beefsteak tomatoes are large tomatoes often used for sandwiches and similar applications; plum tomatoes or paste tomatoes are bred with a higher solid content for use in tomato sauce and paste; and cherry tomatoes are small, often sweet tomatoes generally eaten whole in salads.

Tomatoes are also commonly classified as determinate or indeterminate. Determinate, or bush, types bear a full crop all at once and top off at a specific height; they are often good choices for container growing. Indeterminate varieties develop into vines that never top off and continue producing until killed by frost. As an intermediate ground, there are plants sometimes known as "vigorous determinate" or "semi-determinate"; these top off like determinates but produce a second crop after the initial crop. Many, if not all, tomatoes described as heirlooms are indeterminate.

Commonly grown varieties include:

 * Beefsteak VFN (a common hybrid resistant to Verticillium, Fusarium, and Nematodes)
 * Big Boy (a very common determinate garden cultivar in the United States)
 * Black Krim (a purple-and-red variety from the Crimea)
 * Brandywine (a pink, indeterminate beefsteak type with a considerable number of substrains)
 * Burpee VF (an early attempt at disease resistance in a commercial tomato)
 * Early Girl (an early-maturing globe type)
 * Gardener's Delight (a smaller English variety)
 * Juliet (a grape tomato developed as a substitute for the rare Santa F1)
 * Marmande (a heavily ridged variety from southern France; similar to a small beefsteak and available commercially in the US as UglyRipe)
 * Moneymaker (an English greenhouse variety)
 * Mortgage Lifter (a popular heirloom beefsteak known for gigantic fruit)
 * Patio (bred specifically for container gardens)
 * Roma VF (a plum tomato common in supermarkets)
 * Rutgers (an heirloom commercial variety)
 * San Marzano (a plum tomato popular in Italy)
 * Santa F1 (a closely guarded Chinese grape tomato cultivar popular in the USA and parts of southeast Asia)
 * Sweet 100 (a very prolific, indeterminate cherry tomato)
 * Yellow Pear (a yellow, pear-shaped heirloom variety)

Most modern tomato varieties are smooth-surfaced, but older tomato cultivars (and some modern beefsteaks) often show pronounced ribbing, a feature that may have been common to virtually all precolumbian varieties. In addition, tomatoes come in colors other than red, including yellow, orange, pink and purple, though such tomatoes are not widely available in markets.

There is also a considerable gap between commercial and home gardener varieties; home varieties are often bred for flavor to the exclusion of all other qualities, while commercial varieties are bred for such factors as consistent size and shape, disease and pest resistance, and suitability for mechanized picking and shipping.

Diseases and pests
Tomato cultivars vary widely in their resistance to disease. Modern hybrids focus on improving disease resistance over the heirloom plants. One common tomato disease is tobacco mosaic virus, and for this reason smoking or use of tobacco products should be avoided around tomatoes. Various forms of mildew and blight are also common tomato afflictions, which is why tomato varieties are usually marked with letters like VFN, which refers to disease resistance to verticillium wilt. fusarium fungus, and nematodes.

Some common tomato pests are cutworms, tomato hornworms, aphids, cabbage loopers, whiteflies, tomato fruitworms, flea beetles, and Colorado potato beetles.

Transplanted tomatoes may begin to show yellow leaves at the base. According to hothouse tomato pioneer, Dan Busch, "With your leaves turning yellow, the tomato plant needs to be fertilized. The fertilizer that you need to use needs to be well balanced, meaning 20-20-20, and if you do not want to use this kind of fertilizer, use blood meal and fish emulsions. This will give you a good source of nitrogen, then you will need to add phosphorus (rock phosphate or super phosphate). Slow growing plants is a sure sign of low phosphorus. Be sure to read the instructions on the blood meal and fish emulsion because it is easy to over fertilize. The real issue here is the nutrition. The yellowing of the leaves is not uncommon with a new transplant, because any nutrition is gone by the time you take it home. If the plants are weak, this is an indication of low potassium. To get potassium in the soil you can add granite dust or wood ash. Call around to local garden centers to find these items.

Pollination
In the wild, original state, tomatoes required cross pollination; they were much more self incompatible than domestic cultivars. As a floral device to reduce selfing, the pistils of wild varieties extended farther out of the flower than today's varieties. The stamens were, and remain, entirely within the closed corolla.

As tomatoes were moved from their native areas, their traditional pollinators, (probably a species of halictid bee) did not move with them. The trait of self fertilility (or self pollenizing) became an advantage and domestic cultivars of tomato have been selected to maximize this trait. This is not the same as self-pollination, despite the common claim that tomatoes do so. That tomatoes pollinate themselves poorly without outside aid is clearly shown in greenhouse situations where pollination must be aided by artificial wind, vibration of the plants (one brand of vibrator is a wand called an "electric bee" that is used manually), or more often today, by cultured bumblebees.

The anther of a tomato flower is shaped like a hollow tube, with the pollen produced within the structure rather than on the surface, as with most species. The pollen moves through pores in the anther, but very little pollen is shed without some kind of outside motion.

The best source of outside motion is a sonicating bee such as a bumblebee or the original wild halictid pollinator. In an outside setting, wind or biological agents provide sufficient motion to produce commercially viable crops.

Hydroponic and greenhouse cultivation
Tomatoes are often grown in greenhouses in cooler climates, and indeed there are varieties such as the British "Moneymaker" and a number of cultivars grown in Siberia that are specifically bred for indoor growing. In more temperate climates it is not uncommon to start seeds for future transplant in greenhouses during the late winter as well.

Hydroponic tomatoes are also available, and the technique is often used in hostile growing environments as well as high-density plantings.

Picking and ripening
Tomatoes are often picked unripe (which are colored green at the time), and ripened in storage with ethylene. Ethylene is the plant hormone produced by many fruits and acts as the cue to begin the ripening process. These tend to keep longer, but have poorer flavor and a mealier, starchier texture than tomatoes ripened on the plant. They may be recognized by their color, which is more pink or orange than the ripe tomato's deep red.

In 1994, Calgene introduced a genetically modified tomato called the FlavrSavr which could be vine ripened without compromising shelf-life. However, the product was not commercially sucessful (see main article for details) and was only sold until 1997.

Recently, stores have begun selling "tomatoes on the vine" which are ripened still connected to a piece of vine. These tend to have more flavor (at a price premium) than artificially-ripened tomatoes, but still may not be the equal of local garden produce.

Also relatively recently, slow-ripening cultivars of tomato have been developed by crossing a non-ripening variety with ordinary tomato cultivars. Cultivars were selected whose fruits have a long shelf life and at least reasonable flavor. These have been nicknamed "Thrushworthy Bumbletots," as the name of them is the name of the machine system(s) used to clean the tomatoes before processing to be canned or shipped. The name is an example of onomatopoeia.

<<<

title: Talk:Horticulture/Tomato


text:
Talk:Nissan 240SX Performance Modification/Ignition and Fuel Management/MAF

A mass air flow sensor is usually mounted to the intake manifold or intake tube after the filter. It records and measure the amount of air and the temperature of air entering the Intake manifold. The MAF sensor sends that data to the Engine Computer, wich in turn, decides how much fuel to send into the combustion chamber, to create a good Fuel/Air mixtuer.


text:
User talk:TurnageAlfonso

I am confused! I've read the instructions as best as I can, yet there are still important sections that are unfinished. I am obviously not perfect, and would love help to get into this important-sounding lessons! Alfonso Jermaine Turnage!

title: User talk:TurnageAlfonso


text:
User:Eskroni

Hi,

just a few words about myself:

I'm German, and want to contribute to this wikibook by adding some sound files. I'm a native German speaker and will try to speak slow and clear, that everyone can understand and repeat the exercises.

Some private informations: Currently, I'm 34 years old, live in the south west of Germany, close to the French border and I'm studying microsystems technology.

If you want to know more, please ask :)

Sigrid

title: User:Eskroni


text:
Bartending/Cocktails/Eccentric Elmer

The Eccentric Elmer is a relatively smooth bourbon cocktail, sweet with a hint of bitterness. Note that it is important to use cranberry cocktail, not cranberry juice. If cranberry cocktail is not available in your area, substitute cranberry juice and add 1 tbsp of superfine sugar to the drink before shaking.

Ingredients
Garnishes
 * 1 oz bourbon
 * 1/2 oz triple sec
 * 3 oz cranberry cocktail
 * dash angostura bitters
 * Lime wedge

Glass

 * Old-fashioned

Procedure

 * 1) Fill a cocktail shaker halfway with ice.
 * 2) Add bourbon, triple sec, bitters, and cranberry cocktail to shaker.
 * 3) Shake well.
 * 4) Put a few ice cubes into an old-fashioned glass.
 * 5) Strain cocktail into glass.
 * 6) Garnish with lime wedge.

Eccentric Elmer

title: Bartending/Cocktails/Eccentric Elmer


text:
RC Airplane/SPAD Community

=SPAD Community=

Finding local SPADers
Here are some ways to find other SPAD enthusiasts. Don't hesitate to reach out to other SPAD flyers and builders who will be happy to chat, advice and even fly with you:

 * Frappr - A great dynamic map of the US showing where registered SPAD flyers can be found.
 * SPADonian Locator Service

title: RC Airplane/SPAD Community


text:
Topology/Tangent Spaces

Briefly, a tangent is a derivative of a curve. Translated into topology this means that you can effectively remove one dimension from a picture. Typically, when working with space time we can can perform one of two operations: Either remove time as a way to see frozen 3D images or we can remove one spatial dimension and therefore represent space time as a curved surface (the net like drawings so typically used to represent topological surfaces in pictures or such phenomena as black holes which are often drawn as shrinking cones).

Tangent spaces are therefore only a representation of what we understand to be one dimension simpler than the problems of topology. It is a useful tool for visualising space time arguments and positions.

Euclidean prelude
So far we have defined smooth maps on smooth manifolds by requiring the corresponding maps on euclidean space to be smooth. In this section we will generalize the notion of derivative on euclidean space to a notion of the derivative of functions between manifolds.

Recall our definition of the derivative on euclidean space:

Definition 1: Let $$f\,:\, \mathbb{R}^m\rightarrow\mathbb{R}^n$$. Then the derivative of $$f$$ at $$p$$, if it exists, is a linear map $$Df(p)\,:\,\mathbb{R}^m\rightarrow \mathbb{R}^n$$ such that

 * $$\lim_{h\rightarrow 0} \frac{f(p+h)-f(p)-Df(p)h}{||h||}=0$$

Remark 2: $$Df(p)$$ is unique if it exists, and can be identified with the jacobian matrix $$\left[ \frac{\partial f_i}{\partial x_j} \right]_{n\times m}$$. This is left as an exercise to the reader. This way of defining the derivative does nt, unfortunately, lend itself to generalization to the manifold level. Instead, we will construct another definition of the derivative on euclidean space.

Definition 3: A smooth curve on $$\mathbb{R}^m$$ is a smooth function $$\gamma\,:\, \mathbb{R}\rightarrow \mathbb{R}^m$$. Let $$\gamma,\delta$$ be smooth curves on $$\mathbb{R}^m$$ such that $$\gamma(0)=\delta(0)$$. Define the equivalence relation $$\gamma\sim\delta\,\Leftrightarrow\, \gamma^\prime (0)=\delta^\prime (0)$$. Define the tangent space of $$\mathbb{R}^m$$ at $$p$$ as the space $$T_p\mathbb{R}^m$$ of all equivalence classes $$[\gamma]$$ of smooth curves $$\gamma$$ on $$\mathbb{R}^m$$ such that $$\gamma(0)=p$$.

Remark 4: Note that we only need smooth curves to be defined on an open subset of $$\mathbb{R}$$ containing $$0$$.

Lemma 5: $$T_p\mathbb{R}^m$$ is isomorphic to $$\mathbb{R}^m$$ as a vector space for any $$p\in \mathbb{R}^m$$.

Proof: Since for any smooth curve $$\gamma$$ on $$\mathbb{R}^m$$, $$\gamma^\prime(0)$$ is a vector in $$\mathbb{R}^m$$, there is a natural bijection $$[\gamma]\mapsto \gamma^\prime(0)$$. Let $$\mu$$ be this bijection, and give $$T_p\mathbb{R}^m$$ the vector space structure $$a[\gamma] + b[\delta]=\mu^{-1}\left(a\mu([\gamma])+b\mu([\delta]) \right)$$, and $$\mu$$ becomes an isomorphism of vector spaces.

Remark 6: Unlike $$\mathbb{R}^m$$, $$T_p\mathbb{R}^m$$ does not have a natural basis.

Lemma 7: Let $$\gamma$$ be a smooth curve on $$\mathbb{R}^m$$ with $$\gamma(0)=p$$ and $$\gamma^\prime(0)=v$$. Then $$\gamma\sim \delta$$ where $$\delta(t)=p+vt$$.

Proof: First off, note that $$\gamma(0)=p=\delta(0)$$, so it makes sense to compare them. Secondly, $$\delta^\prime(0)=v=\gamma^\prime(0)$$, so $$\gamma\sim\delta$$.

Definition 8: Let $$f\,:\,\mathbb{R}^m\rightarrow \mathbb{R}^n$$ be a smooth function. Then the differential of $$f$$ at $$p$$ is the map $$d_pf\,:\,T_p\mathbb{R}^m\rightarrow T_{f(p)}\mathbb{R}^n$$ given by $$d_pf([\gamma])=[f\circ \gamma]$$.

Lemma 9: $$d_pf$$ is well defined.

Proof: Let $$\gamma\sim\delta$$ where $$\gamma(0)=p=\delta(0)$$. Then $$(f\circ \gamma)^\prime (0)=Df(\gamma(0))\gamma^\prime(0)=Df(\delta(0))\delta^\prime(0)=(f\circ \delta)^\prime(0)$$ by the chain rule and using the usual derivative, therefore $$[f\circ \gamma]=[f\circ\delta]$$ and so $$d_pf$$ is well defined.

Lemma 10: Let $$f(p)=g(p)$$. Then if $$Df(p)=D(g)(p)$$, then $$d_pf=d_pg$$.

Proof: Let $$\gamma$$ be any curve at $$p$$. Then if $$Df(p)=Dg(p)$$ we have $$d_pf([\gamma])=[f\circ \gamma]=[f(p)+Df(p)\gamma^\prime(0)t]=[g(p)+Dg(p)\gamma^\prime(0)t]=[g\circ \gamma]=d_pg([\gamma])$$.

Thus the differential encodes the information about the derivative. However, it also encodes information about $$f(p)$$. Unlike the previous definition of the derivative, the differential can, with some slight modifications, be generalized to work on manifolds. That is the topic of the next subsection.

Tangent Spaces
Definition 11: A smooth curve on a manifold $$M$$ at $$p$$ is a function $$\gamma\,:\,\mathbb{R}\rightarrow M$$ such that $$\gamma(0)=p$$. If $$\gamma,\delta$$ are smooth curves on $$M$$ at $$p$$, we define the equivalence relation $$\gamma\sim\delta$$ if and only if there exists a chart $$(U,\phi)$$ with $$p\in U$$ such that $$(\phi\circ\gamma)^\prime(0)=(\phi\circ\delta)^\prime(0)$$.

Remark 12: We can differentiate $$(\phi\circ\gamma)$$ since it is a function between euclidean spaces, for which we already have a developed theory of differentiation. Also, the equivalence relation is well defined since if it holds for one chart, it holds for all compatible charts as well.

Definition 13: The tangent space of $$M$$ at $$p$$ is the space of all equivalence classes of curves on $$M$$ at $$p$$.

title: Topology/Tangent Spaces


text:
RC Airplane/SPAD

Introduction
"Spad is the simple concept of offering free plans and ideas for designing very cheap, great flying airplanes made from Coroplast, gutterpipe, aluminum, or anything else we can find that works! The Spad concept is also the world wide sharing of these ideas and most of all, having fun with our hobby!"

The above quote is from spadtothebone written by the founders of the SPAD concept. SPAD stand fo "Simple Plastic Airplane Design" and refers to the construction method as well as the philosophy. SPAD plans are almost always published freely online and shared, so you could describe it as unofficially open source.

This section's eventual aim is to archive and collect every scrap of information that could possibly be useful in building and flying SPAD model aircraft.

Why SPAD?
Another quote from spadtothebone goes like this:

"Less money. Less work. Less fear. More flying."

That is, essentially, what SPAD is all about. SPADs are, on the most part, very ugly (with a few notable exceptions) but this is mostly due to the fact that they are designed to be functional, not aesthetic. SPADs are on the whole extremely tough and surprisingly good fliers, if constructed well.

Advantages:

 * Tough
 * Easy and very quick to build
 * Very cheap to make (averaging less than £5 ($10) per airframe)
 * Fly well

Disadvantages:

 * Ugly
 * Fellow club members may be hostile, although usually they are converted after they see how it fares in a crash.

"Trim it in the air."

These characteristics of SPADs make them ideal for use as trainers, r/c combat planes, or just tough old sport models. What they are NOT are beautiful pieces of painstaking engineering. In fact, a common trend of experienced SPAD modellers is to find the quickest most effective way of building, rather than the most sophisticated. For example, there are some who stick their entire models together with double sided tape, and no glue or screws. This is just one example of the openness of SPAD.

Where do I start?
Well, if you are prepared to embrace the SPAD philosophy and community, a great place to start would be on one of the many SPAD forums. These contain a wealth of information, and can be found in the links section at the bottom of this page. Read, read, read and drink in as much information as possible. This is the best way to start off in this hobby. Join one of the forums, introduce yourself and there will be many people there willing to help you.

If this is your first plane, you will need to start with a trainer. The SPAD plans page [nb: under construction] is a great place to start, along with spadtothebone.com. It is also very strongly recommended to FIND A CLUB. Teaching oneself to fly, even with SPADs is a very disapointing experience. Most clubs will offer to help you learn to fly your plane.

If you are already an experienced pilot, something more sporty like a Draco might be a good place to start.

Once you become more experience, the sky truly is the limit for spad designs.

Forums

 * spadcombat.com [A small but friendly, rapidly growing spad community based mainly in the UK]
 * spadworld.net [The largest resource of SPAD information, very helpful forum]
 * rcmodelflyers.co.uk [A UK based site, excellent for general R/C info, they also have a small SPAD section]
 * rcuniverse.com [A massive resource on every R/C section imaginable, including SPADs]

Information Sites

 * spadtothebone.net [The site where it all started]

title: RC Airplane/SPAD


text:
Talk:World History/Revolution, Change, and philosophy

Scheme:

 * English Civil War destroyed monarchical power in a western state.
 * Bill of Rights and philosophical movements in late 17th early 18th centuries.
 * America as a recipient of the most radical non-conformists of the Civil War
 * Government of American Colonies used the new parliamentary approach
 * US Bill of Rights extends Bill of Rights beyond first 8 amendments
 * The effect of the Revolutionary War/War of Independence on French combatants.
 * Movement of intellectuals from US and Britain to France
 * Voltaire etc
 * French Revolution
 * The inspiration of the US and French revolutions in the 19th century


text:
A-level Physics/Telecommunications

Electronic signals Communication Principles Digital Systems Amplifliers Radios Optic Fibres Systems and Networking

a useful site

title: A-level Physics/Telecommunications


text:
GStreamer

Gstreamer is a powerful program and library for media processing. Its power lies in the fact that media data streams between elements performing many functions. Elements can be added by means of plugins. Here is an example of a command to convert a FLAC format song to MP3 format: gst-launch filesrc location = "02 - Duel of the Fates.flac" ! flacdec ! lame ! filesink location = "Duel of the Fates.mp3"

Some of its most popular uses include:
 * Playing music and video (from command line or a program using the library)
 * Format conversion
 * Recording directly to a certain format.

This book will provide an introduction and in-depth tutorial to GStreamer.

Contents

 * Introduction
 * Obtaining GStreamer
 * Quick Examples
 * Programs Using GStreamer

title: GStreamer


text:
User:Alfonso Jermaine Turnage

 * Student

title: User:Alfonso Jermaine Turnage


text:
User talk:Schoeberl

Creating a microphone for JOP
This book module appears to be a stub or an orphan of some variety. You are listed as one of the contributors, so I will give you a chance to reclaim it. Nothing links to this page, and it doesnt appear to be associated with any particular book or bookshelf. I am going to list this book on WB:VFD unless you think it is valuable enough to keep. A condition of keeping this book, however, is that it gets linked to an appropriate book or bookshelf. --Whiteknight (talk) (projects) 16:43, 8 June 2006 (UTC)

It is part of a Wikiversity course School_of_Very_Small_Information_Systems and linked from there.

 * Okay, fair enough. I just wanted to make sure that it had a good home. --Whiteknight (talk) (projects) 22:15, 25 June 2006 (UTC)

title: User talk:Schoeberl


text:
Spanish/Lesson 10

Grammar - Future
In Spanish, the future has the same function as the future in English - to state things that will happen. Its use is equal to verbs ending in -ar, -er and -ir for regular verbs.

Example:

There are some irregular verbs that have different conjugations in the future for the first person - yo:
 * venir: vendr - é
 * tener: tendr - é
 * poner: pondr - é
 * salir: saldr - é
 * poder: podr - é
 * hacer: har - é
 * querer: querr - é

Soon realization
To express a plan for soon realization you need to use ir a + infinitivo. Example: Voy a visitar mi amigo. This means I'll leave to visit my friend soon, maybe in the next hour.

Realization decided
To express that a plan is really going to happen you need to use pensar + infinitivo. Example: Penso visitar mi amigo. This means I will, but maybe in weekend, maybe next week.

Realization not decided yet
To express that a plan may happen as you are not sure use estar pensando en  + infinitivo. Example: Estoy pensando en visitar mi amigo. This means I am just planning, not sure yet.

title: Spanish/Lesson 10


text:
Talk:GStreamer

This book should describe Gstreamer and its capabilities, and explain how to do anything within reason that can be done. I am learning GStreamer as I go along, and I hope to be able to share what I have learned and learn from other contributors. The preferred format for explaining how to do something is to give an example command, and then explain each part of the command, along with any alternatives and their explanations. Ab8uu 17:43, 8 June 2006 (UTC)

title: Talk:GStreamer


text:
GStreamer/Introduction/Programs Using GStreamer

This is a short list of programs that use GStreamer, with a description of each program.

Rhythmbox
Rythmbox is a music player and organizer. By using GStreamer, it can play any format of music that you have a GStreamer plugin for. It uses Sound-Juicer (below) to rip CDs, and also imports files and folders, reading song information from tags.

Sound-Juicer
Sound-Juicer is a program that uses GStreamer to rip CDs to FLAC, OGG, MP3, WAV, and other formats.

Whaawmp
Whaawmp is a Gtk+ media player, similar to totem, written in python.

Clementine
Clementine is a Qt4-based audio player similar to Amarok 1.4.