Mohammad Hosein Houshmandrad
email: hoseinhoushmandrad@gmail.com

Mahsa Mokhtari

Hourvash Khodahemmati

Shayan Alipour

Investigation the position of gardens as one of the dimensions of urban vegetation in the management of large cities located in the plains and its maintenance strategies

Keywords: Garden, Plain, Ecology, Metropolis, Urban Management

d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Investigation the position of gardens as one of the dimensions of urban vegetation in the management of large cities located in the plains and its maintenance strategies

Mohammad Hosein Houshmandrad, Mahsa Mokhtari, Hourvash

Khodahemmati, Shayan Alipour

To cite this version:

Mohammad Hosein Houshmandrad, Mahsa Mokhtari, Hourvash Khodahemmati, Shayan Alipour. Investigation the position of gardens as one of the dimensions of urban vegetation in the management of large cities located in the plains and its maintenance strategies. 8th International Conference of Agriculture Engineering, Natural Resources and Environment, Sep 2022, Tehran, Iran. hal-03762316v2

INTRODUCTION

Iranian gardens play a key role in the formation of the city and the landscapes of traditional Iranian cities and are considered to be the reason for the connection of architectural seeds, green infrastructure and natural organs of the city. The Iranian garden is one of the masterpieces of outdoor design in the world and is the result of the thought of a people interacting with nature and using nature to create an outdoor space [START_REF] Shaybani | The position of the Iranian garden in the urban landscape[END_REF]. The city is a social arena that is created on the natural arena [START_REF] Rahmana | Analysis of change of use and how to preserve and maintain green space in line with sustainable development[END_REF]. Urbanization, as the second revolution in human culture, has caused a transformation in the mutual relations of humans with each other, with the increase of the urban population, the exploitation of the environment intensifies [START_REF] Seraei | Examining the level of sustainability of development in cities in arid regions with an emphasis on bio-environmental components: Ardakan city[END_REF]. The increase in population and expansion of urbanization causes urban green spaces to become rough and impenetrable concrete surfaces; And this trend is more serious especially in developing countries and the third world [START_REF] Shi | Suitability Analysis and Decision Making Using GIS[END_REF]. It seems that in Iran, cities that have faced the problem of rapid expansion of their settlements, this development is associated with the destruction and destruction of urban gardens. In other words, a large part of the land required for the physical development of the cities has been obtained by changing the use of the garden area [START_REF] Ismaeilpour | Change in agricultural land use and relative temperature increase in Yazd city due to its rapid growth[END_REF]. The expansion of cities, the increase of urban population, the expansion of urbanization and human progress in the field of technology have caused the gradual distance of man from nature and the destruction of the ecological balance of the environment. Excessive population density and interference in the natural environment and the creation of environments that are designed and built with human thought, reveal more and more the physical and mental environmental needs of humans [START_REF] Sadrmoussi | Analysis on the physical development of Tabriz and the destruction of agricultural lands and urban green space[END_REF]. Therefore, the administrators in the urban area takes decisions to solve this deficiency by building gardens and artificial green spaces inside the cities. Gardens, as one of the unique aspects of urban green spaces, produce oxygen, reduce pollution caused by industrial fine dust in the atmosphere, regulate temperature, stabilize soil, beautify the environment, control pollution, and create artificial air arteries and generate wind in cities. They are located in the plain area. It is worth mentioning that the cities located in the plains do not have natural lungs of air and these gardens are the rule. The artificial lungs of the cities located in the plain area play a role [START_REF] Amiri | The importance and role of green spaces in the city and urban planning[END_REF]. Preserving gardens and preventing their degeneration in the urban area is one of the means to achieve the realization of sustainable development in urban management. It is worth pointing out that for the development of the urban space and area, the cause of the destruction of the gardens is first provided, and after understanding its place and importance, the destroyed space is replaced. The occurrence of this vicious cycle, in addition to incurring exorbitant costs in the management of megacities, makes the efforts of third world and developing countries to achieve sustainable development fruitless.

Plain

Geographically, the plain refers to flat or relatively flat lands that are surrounded by high mountains and these lands generally have one or more flowing rivers. The cities located in the mentioned position generally lack the natural lung of air flow due to being monopolized and isolated by high mountain ranges, i.e. not benefiting from the passage of natural wind in the plains [START_REF] Shoqi | [END_REF].

Functional separation of cities from the consequences of modernism

A behavioral camp is a small social unit that results from the stable integration of an activity and a place in such a way that it can fulfill the essential functions of that behavioral environment in a regular process [START_REF] Gulrokh | Behavareh camp: a basic unit for environmental analysis[END_REF]. Modernism reduced the behavioral function of the formed behavioral camps of the city and threatened the established behavioral camps throughout history and basically due to the characteristics such as crudeness, slowness, inflexibility and difficulty of creating a camp. did not have the new ones [START_REF] Shirazian | Guide to historical maps of Tehran[END_REF]. Such consequences in Iran started from the first Pahlavi period with the implementation of the map (street implementation) and damaged many urban gathering places that were the behavioral base of urban pedestrian flows. Today's urban parks are the result of developments in the field of social life and ways of constructing gardens, which began in the Qajar period along with other aspects of architecture and urban planning, but in the Qajar era and the early Pahlavi era, the need for a park in its modern sense It was not felt and the construction or naming of such spaces had more of an imitative and modernist aspect [START_REF] Masoud | Contemporary architecture of Iran: in the struggle between tradition and modernity[END_REF].

The role of gardens in the formation of behavioral norms

Before the first Pahlavi period, the effective and ineffective gardens were one of the components of the local scale, which as an intermediary element in combination with other urban components such as schools, mosques, tombs, almshouses or in the form of a collection of concentrated gardens in the cities. has forgiven. The emergence of large government gardens with aristocratic mansions, as well as newly emerging imported elements such as the zoo, in the second period of Naser al-Din Shah Qajar's rule and after that, became the basis for the creation of urban parks in the process of the city's peaceful development. This dialectical flow intensified the concept of urban gardens to provide livelihood and entertainment for the common people and the aristocratic concept of green space and designed plants. Nevertheless, until the beginning of the first Pahlavi period, productive and non-productive gardens maintained their value and importance for the public as multi-functional green spaces. In the process of forming and stabilizing the landscape of fine-grained gardens in the city, intra-tissue feedbacks between gardens and other components of small arsenics on a local scale and the role of monitoring residential contexts, cause an increase in behavioral performance, flexibility and, as a result, a sense of belonging to these gardens. have been. With the beginning of the sudden changes of the first Pahlavi period with emphasis on the human society, a modernity was formed in Iran, which, unlike the endogenous modernity of the western society, was not formed based on the gradual changes in the cultural structure of the society. The result of this process was the phenomenon of physical and cultural separation instead of the integration of inner city forces. Even before modernity, the inner city garden had a high behavioral performance by having a local scale and covering a wide range of behaviors supporting this scale., they had a more non-diverse behavioral spectrum and heterogeneity with the needs of the urban cultural context. The result of this process was the gradual loss of the spiritual value of these fine-grained gardens and finally the beginning of destruction and replacement with building masses [START_REF] Zandi | The role of urban gardens in the formation of behavioral camps, a case study of Tehran[END_REF].

The place and importance of gardens

The destruction of gardens in Iran's big cities is not only happening during their development, but also now. Municipalities have not been able to effectively control the destruction of gardens due to lack of full authority. Although the approval of some laws has been able to increase the scope of the municipalities' powers, but there are still widespread violations caused by the deliberate drying of gardens in these megacities [START_REF] Azizi | sustainable urban development, a view and analysis from a global perspective[END_REF]. The significant decrease in the area of gardens in Tehran from 14,000 hectares in 1968 to 9,900 hectares in 1981 and the decrease in the area of gardens in Shiraz from about 4,000 hectares to 1,200 hectares in 1992 is self-evident and a proof of this claim. It can be said that the main reason for the extensive destruction of these gardens is, on the one hand, their placement in the path of urban development, and on the other hand, the significant increase in the added value of these gardens for their owners [START_REF] Rahmana | Analysis of change of use and how to preserve and maintain green space in line with sustainable development[END_REF].

Figure 3 .Aerial view of the gardens of Qasr al-Dasht area of Shiraz, between 2002 and 2014

The importance of the functioning of gardens in the cities that are geographically located in the plains is so much that in case of destruction, it can be claimed that they have no alternative and their removal in any way and for any reason will cause irreparable damage to the city and the urban area. and it brings in its residents and severely challenges the city management. Considering that these gardens are located in a dense and consecutive area, they will follow the following mechanisms:

5-1 Increase in relative humidity

Due to the expansion of its leaf surface compared to other forms of green space, gardens can increase the relative humidity and softness of the air through transpiration. The act of sweating trees is associated with the absorption of calories. Thus, a strip of plants 50 to 100 meters wide reduces the heat by 3 to 4 degrees compared to the city center. At the same time, it adds 50% to air humidity. The temperature difference obtained in this way causes a slight decrease in air pressure. A decrease in air pressure creates winds with a speed of 12 km per hour, and these winds are enough to completely change and clean the air of a big city in one hour [START_REF] Nejad Shirazi | Re-creating the principles of sustainable landscape and energy storage. 6th Renewable[END_REF].

5-2 Dealing with heat islands

Researchers consider urban areas as heat islands; Dark surfaces in cities absorb the sun's heat during the day by 3 to 5 degrees Celsius more than the adjacent lands, and in this way contribute to 30% of air pollution. In urban areas where buildings and plumbing systems have the largest contribution to the earth's surface coverage ,natural cycles are short, and the disturbance in energy transfer has turned them into heat islands. In turn, it increases the pollution of the city [START_REF] Nejad Shirazi | Re-creating the principles of sustainable landscape and energy storage. 6th Renewable[END_REF].

5-3 Reducing the amount of lead

Gardens play an effective role in reducing lead levels. Comparative comparison of trees with other types of plants, such as herbaceous plants and agricultural plants, shows that trees have 10 to 20 times the capacity of herbaceous plants and 2 times of agricultural plants to absorb lead [START_REF] Tabibian | Investigation of the absorption rate of heavy metal lead in the sycamore tree species in traffic areas[END_REF].

5-4 Gardens and wind production

Due to the production of oxygen by gardens and forests, and as a result, the creation of wind by the produced oxygen, forests and gardens are always known as wind factories in both small and large dimensions. Therefore, in the case of big cities located in the plains, gardens are referred to as artificial lungs that produce wind. It is worth mentioning that the wind carries the role of transporting pollutants in both vertical and horizontal directions [START_REF] Sardo | Urban green space and its role in people's lives[END_REF].

5-5 Preventing the phenomenon of air inversion

It is a phenomenon in which, contrary to the natural state, the temperature increases with the increase in altitude, and in this condition, the temperature of the lower layer of the atmosphere is lower than its upper layer. In big cities, temperature inversion usually causes air pollution. Among the reasons for the occurrence of this phenomenon, we can point out the lack of movement between vertical layers of the atmosphere due to the lack of wind, the presence of enclosing mountain ranges, the lack of wind entering the plain, low rainfall, etc [START_REF] Sardo | Urban green space and its role in people's lives[END_REF].

5-6 Noise

Trees in gardens and urban green spaces, if they have the right species and proper planting, can reduce the sound up to 4 decibels. In particular, it reduces noise pollution caused by vehicles and urban transport fleet [START_REF] Nejad Shirazi | Re-creating the principles of sustainable landscape and energy storage. 6th Renewable[END_REF][START_REF] Mobasseri | Impact of driving style on fuel consumption[END_REF][START_REF] Mobasseri | Traffic noise and it's measurement methods[END_REF][START_REF] Mobasseri | A Comparative Study Between ABS and Disc Brake System Using Finite Element Method[END_REF][START_REF] Yofianti | Relationship of plant types to noise pollution absorption level to improve the quality of the road environment[END_REF][START_REF] Houshmandrad | Choosing the most optimal type of contract in infrastructure projects from the employer's point of view in the field of technical participation and getting rid of the pressures of liquidity provision[END_REF]. To simulate noise pollution, the Finite Element Method (FEM) is a suitable and practical tool [START_REF] Mobasseri | Bending and Torsional Rigidities of Defected Femur Bone using Finite Element Method[END_REF][START_REF] Mobasseri | Approximated 3D non-homogeneous model for the buckling and vibration analysis of femur bone with femoral defects[END_REF][START_REF] Habibi | Drug delivery with therapeutic lens for the glaucoma treatment in the anterior eye chamber: a numerical simulation[END_REF][START_REF] Sarmadi | SIMULATION OF NOISE POLLUTION REDUCTION IN A POWER PLANT UNDER CONSTRUCTION USING ANSYS FLUENT SOFTWARE[END_REF][START_REF] Mobasseri | Intelligent Circuit Application for Detecting the amount of Air in Automobile Tires[END_REF][START_REF] Mobasseri | Intelligent Circuit Application for Monitoring the Employees Attendance[END_REF].

5-7 Oxygen production and carbon dioxide absorption

In the urban macro scale, the role of gardens in terms of creating oxygen balance by trees can be significant, and in the urban micro scale, they cannot be ignored in any way. For example, each beech tree with a medium longevity can remove carbon dioxide from the air as much as three times the volume of two single rooms, while 30 to 40 square meters of trees can provide the oxygen needed by one person [START_REF] Fard | The impact and role of trees in the urban landscape and environment[END_REF].

5-8 Radiation control and light reflection

Climate control is realized by modulating the effects of sun, wind and rain. The air temperature in the vicinity of trees is much cooler than in areas without trees. The bigger the tree, the bigger the difference. Absorption of solar radiation (long waves) by trees reduces the temperature difference between day and night. The air under the trees is cooler during the day and warmer at night [START_REF] Fard | The impact and role of trees in the urban landscape and environment[END_REF].

5-9 Energy storage

Proper planting of trees can have a significant effect on energy consumption in buildings. The cost of heating or cooling buildings is reduced if trees are used correctly. Trees absorb 9% of solar energy in summer and can also reduce the internal heat of buildings. In residential areas that are located in windy areas, planting trees as windbreaks can reduce the cost of heating buildings by 4 to 22% depending on the degree of windiness and density of the windbreak [START_REF] Feridouni | Identification of factors affecting energy supply and consumption in Iran with the approach of reforming the pure model[END_REF].

5-10 Wind control

Urban green spaces and especially gardens can be effective in guiding the wind and changing its direction. Urban green spaces, including trees and shrubs, have an effect on wind currents, while preventing soil erosion, they can be effective in selectively directing wind currents and control wind intensity [START_REF] Parisi | mutual effects of wind and trees and shrubs of urban green spaces and ways to reduce wind damage. the first national wind erosion conference[END_REF].

5-11 Water flow control

Trees can slow down the movement and flow of water in the impenetrable surface of the city and delay the passage of water on the surface of the city. Conifer trees up to 40% and broadleaf trees up to 20% have the ability to capture rainwater and return it to the atmosphere through evaporation [START_REF] Fard | The impact and role of trees in the urban landscape and environment[END_REF].

5-12 Trees and floods

By absorbing water from one side and directing it to their organs, trees slow down rapid and flood currents. On the one hand, the surface of tree limbs reduces the speed of floods by one-third and on the other hand, it reduces the costs of constructing flood flow control systems [START_REF] Parisi | mutual effects of wind and trees and shrubs of urban green spaces and ways to reduce wind damage. the first national wind erosion conference[END_REF].

CONCLUSION

Considering the ever-increasing growth of urbanization and the development of urban areas, which causes extensive changes in the field of gardens, and the feeling of the need to increase the urban green space per capita by citizens and urban management in big cities, all of them indicate the strategic importance of gardens as one of the forms of green space to It is special for big cities located in the plains. Considering the ecological effects of gardens on the urban area, such as reducing the amount of lead, dealing with heat islands, preventing the phenomenon of air inversion, increasing relative humidity, controlling radiation, light reflection, etc., urban management is forced to search for solutions to preserve and prevent It has destroyed or changed the use of these gardens, but due to the added financial value of these gardens for the owners and other beneficiaries, it has created problems for the city management in this direction. The suggestions to preserve and prevent the destruction of this treasure are as follows: purchasing these gardens by the municipality and turning them into city parks (either public or family parks); Buying and transferring the ownership of gardens to the Medical Sciences Organization and turning them into botanical and medicinal plant gardens; Creating a memorandum of cooperation between the municipality and the endowment organization in the big cities in order to purchase and endow the gardens in order to prevent their change of use, the acquisition of the gardens by the cultural heritage organization for the use of the museum garden. Changing the use of gardens under the title of garden-school, which can be considered by the Ministry of Education and the private sector active in the field of education, as well as garden-reliance, which, in addition to preserving the body of gardens, can be used as a place for religious and ritual gatherings. be exploited.

Figure 1 .Figure 2 .

 12 Figure 1. Aerial image of Sattar Khan street in Tehran, between 2004 and 2015

7.


Mohammad Hosein Houshmandrad
email: hoseinhoushmandrad@gmail.com

Mahsa Mokhtari

Investigating possible solutions to reduce noise pollution in wind turbines

Keywords: Noise Pollution, Wind Turbine, Reduce Pollution, Blades

In recent years, the use of wind turbines has increased due to the phenomenon of global warming and climate change in different regions, and it is expected that this growth will continue in the future, as is the noise pollution of turbines. Noise pollution is one of the biggest environmental damages using wind turbines, which is within the range of hearing and inaudibility, and this type of pollution can be perceived by other living beings, which can have a negative impact on their lives. Also, the problems of using propellers, such as the noise caused by them, visual problems, the killing of birds and insects, and atmospheric disturbances have also added to the amount of this problem.

Introduction

The potential of using wind resources is far more than the currently used capacity. It is expected that the use of wind turbines will increase in the coming years. It is expected that by 2030, the operating capacity will reach more than 1.2 terawatts (equivalent to 20% of electricity production [START_REF]Global wind energy outlook[END_REF]. Fortunately, it is now possible to design various types of wind turbines for different working conditions, so that it is possible to build small domestic turbines to large marine turbines for installation in areas far from the coast. Small turbines can be easily installed and used in different areas, which have little environmental harm, and their expansion also helps in the development of distributed electricity distribution network. On the other hand, large turbines can be used to exploit large potentials, which are economically less expensive to exploit. These turbines are usually used in multiples, and their collection is called a wind farm. Today, it is possible to make turbines with much larger diameters than in the past, which makes it possible to use more wind energy. The use of wind turbines has its own environmental disadvantages, and in order to expand the use of turbines, these problems must be solved as much as possible. Problems such as the destruction of the environment for the installation of turbine towers, the creation of intermittent bright shadows caused by the rotation of turbine blades, the pressure reduction caused by the flow of eddies downstream of large turbines, and most importantly, the sound pollution (noise) of turbines. Studies show that noise is a problem in the daily life of people who live near wind turbines [START_REF] Bakker | Impact of wind turbine sound on annoyance, self-reported sleep disturbance and psychological distress[END_REF][START_REF] Van Renterghem | Annoyance, detection and recognition of wind turbine noise[END_REF][START_REF] Waye | acoustic characters of relevance for annoyance of wind turbine noise[END_REF][START_REF] Houshmandrad | Choosing the most optimal type of contract in infrastructure projects from the employer's point of view in the field of technical participation and getting rid of the pressures of liquidity provision[END_REF]. The range of human hearing is defined from the frequency of 20-20 Hz to kilohertz, and frequencies less than 20 Hz are called the sub-auditory range. Since wind turbines usually have a small number of blades and their rotation speed is low, their noise at low frequencies and in the sub-audible range should be investigated. Research has shown that the noise of wind turbines at low frequencies will have significant harm on human health [START_REF] Mobasseri | Intelligent Circuit Application for Monitoring the Employees Attendance[END_REF][START_REF] Mobasseri | Traffic noise and it's measurement methods[END_REF]. It causes problems such as headache, lack of concentration, sleep disorder, fatigue, dizziness and constant ringing in the ears (the set of symptoms of the mentioned disease is known as wind turbine syndrome). For example, with a rotational speed of 30 revolutions per second, the noise produced is in the sub-hearing range and causes disturbance in the life of wind power plant personnel [START_REF] Salt | Responses of the ear to low frequency sounds, infrasound and wind turbines[END_REF]. The noise caused by wind turbines can have a negative effect on the hearing system even at hearing frequencies. Of course, in examining the effects of wind turbine noise, it is necessary to pay attention to its effect on other living organisms. The noise of wind turbines is within the hearing range of many animals, birds and insects, and the negative impact of this phenomenon on living beings can threaten the environment and the diversity of animal species in the region [START_REF] Zhu | Modeling of aerodynamically generated noise from wind turbines[END_REF].

Wind turbine

A wind turbine is generally a machine that converts wind energy into electrical energy. In wind turbines, the blades are designed to rotate with the wind. The rotation of the blades rotates the inner axis of the turbine rotor, and finally, after converting the torque into rotational speed in the gearbox, the mechanical power is converted into electrical power. Based on the orientation of the rotating axis, wind turbines are divided into two categories: horizontal axis and vertical axis:

Horizontal axis wind turbines

All components of the turbine (blades, gearbox, generator, etc.) are placed on top of a tall tower in line with the wind. In order to achieve the highest efficiency, these turbines must be placed exactly in the direction of the wind, so horizontal axis turbines must have a system to adjust against the wind, which is called a yawing mechanism. so that the whole nacelle can turn towards the wind. In small turbines, the tail of the fan is responsible for this control. But in systems connected to the network, the yaw control system is active, which rotates the nacelle towards the wind by wind direction sensors and motors.

Advantages of horizontal turbine

The height of the tower provides access to powerful winds. In some places, for every 10 meters increase in height, the wind speed increases by 20% and the efficiency increases by 34%.

Due to the long bases and advanced mechanism, it is possible to use these turbines in the seas.

Due to being directly in front of the wind, they have high efficiency.

Disadvantages of horizontal turbine

They do not work at low altitude.

It is difficult to transport and install them.

Their maintenance is difficult and expensive.

They are affected in the vicinity of the radar.

Their high height and size do not have a beautiful appearance and cause noise pollution.

Vertical axis wind turbines

The main rotor is placed vertically. The most important advantage of vertical wind turbines is that they don't need to be adjusted in relation to the direction of the wind, and they can also be used at low altitudes. In vertical axis turbines or rotors, the rotation axis is perpendicular to the ground and the blades rotate parallel to the ground. For this reason, the surface moved by the wind has to continue moving in the opposite direction of the wind flow after half a revolution, and this problem causes their power factor to decrease. For this reason, the blade curve is very important in these rotors.

Because these wind turbines must be installed closer to the ground and at low altitude, the wind speed is lower, less energy is produced from the specific size of the turbine. Air flow near the ground and other objects can create turbulent flow, which causes vibration consequences, including noise and bearing fatigue, and as a result, maintenance costs may increase and service life may decrease. These turbines are divided into two main types, Savonius and Darrieus.

Advantages of vertical turbines

Vertical wind turbines are less sensitive to wind direction and flow turbulence, this advantage allows them to be used in different areas, including the roof of buildings. They perform well in turbulent and turbulent winds. Vertical wind turbines can be installed close to the ground, which makes them safe and cheap, as well as easy to maintain. They do not need a yawing system.

Disadvantages of vertical turbines

In vertical turbines, when the wind blows, an opposite force is also applied to the other side of the turbine. Therefore, their efficiency in each period is lower than horizontal axis turbines.

It is difficult to install this type of turbine on tall towers; This means that they should operate in slower air currents with more turbulence and near the ground with lower energy extraction efficiency. Due to the mentioned issues, the design and analysis of the blade (airfoil) of vertical turbines is more difficult and expensive.

Their low efficiency can be improved by compact layout and new designs. Due to high flow disturbance, the structure of vertical wind turbines is subject to fatigue. This issue can also be improved to a great extent by predicting aerodynamic loads.

Environmental effects of wind turbine blades

Noise pollution

The Finite Element (FEM) software is one of the most widely used numerical simulation techniques for investigating engineering-industrial phenomena [START_REF] Mobasseri | Intelligent Circuit Application for Detecting the amount of Air in Automobile Tires[END_REF] such as noise pollution [START_REF] Mobasseri | Traffic noise and it's measurement methods[END_REF][START_REF] Mobasseri | Approximated 3D non-homogeneous model for the buckling and vibration analysis of femur bone with femoral defects[END_REF][START_REF] Mobasseri | Bending and Torsional Rigidities of Defected Femur Bone using Finite Element Method[END_REF][START_REF] Mobasseri | A Comparative Study Between ABS and Disc Brake System Using Finite Element Method[END_REF][START_REF] Habibi | Drug delivery with therapeutic lens for the glaucoma treatment in the anterior eye chamber: a numerical simulation[END_REF][START_REF] Mobasseri | Impact of driving style on fuel consumption[END_REF]. Also, the noise of wind turbines is divided into two categories based on the source of its creation:

-Mechanical noise -Aerodynamic noise Mechanical noise is caused by components such as gearbox, generator and bearings and has nothing to do with fluid flow. Currently, by designing and manufacturing gearboxes with almost smooth surfaces, with soft cores but hard surfaces, their noise has been reduced significantly. Also, by using anti-vibration joints and couplings, the mechanical noise of other components can be reduced [START_REF] Wagner | Wind turbine noise[END_REF][START_REF] Zhu | Modelling of noise from wind turbines[END_REF].

Aerodynamic noise is divided into three categories based on the origin of production: low frequency noise; Turbulence noise of the input flow;

Turbine blade inductance noise.

The low frequency noise is caused by noise sources of constant thickness and constant loading around the rotating blade and the change of the speed profile caused by the barrier of the turbine tower path. The turbulence noise of the input flow is related to the presence of eddies in the flow entering the rotor, and considering that the size and number of eddies in the input flow are completely variable, simulating this noise in turbines is a difficult task and due to the changes in the flow at points Different, it is practically not possible to experimentally test this noise in large turbines. But it can be said that large vortices affect the performance of the vane and cause noise in the low frequency range, but small vortices will only locally cause pressure fluctuations and cause high frequency noise. It should be noted that this noise is more important in small turbines than in large turbines [START_REF] Rogers | The effect of turbulence on noise emissions from a micro-scale horizontal axis wind turbine[END_REF].

The turbine blade is known as the most important source of turbine noise, and the noise caused by the turbulence in the boundary layer flow and the eddies resulting from the existence of the blade is called blade noise. The factors that cause noise are the turbulence eddies of the tip of the blades, the separated boundary layer flow and the airfoil remnant, the eddies caused by the instability in the laminar boundary layer flow, the turbulent flow of the boundary layer of the escaping edge and the eddies caused by the width of the escaping edge.

Opponents of wind turbines, due to the fact that the noise produced in wind turbines is infrasound, fuel a condition called wind turbine syndrome and defend their statements that this condition is harmful and causes heart diseases and dizziness. Also, noise pollution can harass animals and insects and make them run away from the wind farm. It can also be dangerous for dolphins and cause increased anxiety, decreased hearing and illness caused by sudden pressure drop, and in the end, they try to breathe quickly and go under water to escape from the noise.

Birds hitting feathers

Perhaps this is the most sensitive part of the problem of wind turbines, and designers try to place wind farms far from the place of bird migration. According to the available statistics, about 8000 birds are killed due to collision with feathers. In addition to birds being killed, bats are also victims of collisions with blades, and the reason for this is the sudden pressure difference and loss of balance. Bats, which play an important role in the ecosystem as insectivores, are at risk of extinction. In Denmark, the study shows that birds are able to identify the presence of turbines during migration, but pressure changes around them cause internal problems in them, and designers are trying to create an optimal distance in wind farms.

Atmospheric disturbances of blades

It has been said that the wind farms themselves cause disruption in air circulation and increase in temperature, which has a negative effect on the atmosphere in the long term. However, according to the research of the French researcher in the "Nature" magazine, the establishment of farms has caused climate changes in Europe to a very small extent and will remain at this level until 2018.

Studying the continental pattern

In a research conducted at the University of Texas, it was found that wind farms have a negative effect on the warming of that area. Researchers have estimated that the temperature of the areas where there are wind turbines is about 72.0 degrees higher than other areas during 10 years. Energy scientists plan to produce more than 200 gigawatts electricity in Europe through wind turbines by 2018, while currently 110 gigawatts have been recorded. since 1987 and based on the commitment that European countries were required to make; 20% of Europe's energy should be through wind [START_REF] Göçmen | Airfoil optimization for noise emission problem and aerodynamic performance criterion on small scale wind turbines[END_REF].

Temperature difference

Comparing the temperature difference between the two environments shows that the maximum temperature difference is 3.0 degrees and this value is higher in winter. Scientists observed some decrease in temperature in the south and increase in temperature in the north, which are caused by the western winds. All these differences are small, and according to Robert and Tard, these differences are very small compared to the differences in the climate system of the world due to greenhouse gases, but research is necessary before the expansion of wind farms.

Generation of lightning by vanes

Wind turbine blades also cause lightning in certain weather conditions. When these vanes reach their maximum height, they create lightning that is sent up to a height of 2 km above the atmosphere. Juan Montaña from the Polytechnic University of Catalonia conducted an experiment in which it was found that several turbines that are located close to each other can generate lightning at the same time.

Determination of wind and storm speed by vanes

According to the studies conducted, wind turbines in the sea can prevent the destructive power of storms. A research group from Stanford University came to the conclusion that the installation of wind turbines in the sea can reduce the damage caused by big storms like the hurricanes that hit the United States.

Disturbing natural views and visual problems

On the way of expansion of wind turbines by the opponents of this industry, there are claims that turbines destroy the natural landscape. In some cases, it is necessary to cut the branches of the trees or the flashing of the wind turbine blades in the horizon and the phenomenon of intermittent flashing occurs due to the passage of light between the blades. If this frequency is between 5 and 20 Hz, it causes a phenomenon called epilepsy, which is a type of vision disease that causes lack of concentration and weakness in the alertness system, but considering that this phenomenon occurs periodically during the daytime hours. It rarely happens, no cases have been observed yet.

Secondary contamination of the environment

The consumption of fossil fuels for the production, transportation, installation and recycling of blades is one of the other problems of this industry, which is increasing day by day [START_REF] Houshmandrad | Investigation the position of gardens as one of the dimensions of urban vegetation in the management of large cities located in the plains and its maintenance strategies[END_REF] .

Solutions to reduce noise pollution in wind turbines

Deformation of blade profile

Gochman and Ozderm optimized the profiles of six well-known airfoils of small wind turbines using a validated code and using Emmitt and Brooks relations for noise simulation [START_REF] Bertagnolio | Trailing edge noise model validation and application to airfoil optimization[END_REF]. Using experimental models, Bertagnolio et al showed that by changing the shape of the profile, it is possible to reduce the sound level by 1 to 3.5 dB [START_REF] Arakawa | Numerical approach for noise reduction of wind turbine blade tip with earth simulator[END_REF]. Araqua also showed changing the shape of the tip of the blade can significantly reduce the sound. It should also be noted that noise reduction should not affect the sound [START_REF] Lowson | Noise evaluation of coning rotor[END_REF].

Changing the three-dimensional layout of the blade

Another method of noise reduction is the three-dimensional change of the blade section. For example, the change of the turbine rotor angle is equivalent to the three-dimensional change of the cross section. By making the turbine conical, the tip of the blade moves down and the diameter of the turbine is reduced, which is considered an advantage because the space required for the turbines is reduced and more turbines can be installed. did Due to the displacement of the tip of the blade towards the rear, the maximum allowed angle in the upstream flow will depend on the permitted distance to the turbine tower, and in the downstream turbines, the downstream turbine can be placed in a cone angle close to 90 degrees. By examining the turbulence noise, Lawson showed that conical rotors do not have much noise increase compared to normal rotors. Crawford also investigated the effect of cone shape on low frequency for downstream wind turbines. In general, it can be said that not much research has been done on this issue [START_REF] Crawford | Advanced engineering models for wind turbines with application to the design of a coning rotor concept[END_REF][START_REF] Howe | Aerodynamic noise of a serrated trailing edge[END_REF].

Serration of the trailing edge of the vane

One of the effective methods is serration of the blade (cactus). In 1991, Howe showed that this reduces noise. This was the starting point for research in this field, when it was shown that serrations of flat blades and different airfoils can reduce noise. Brown et al. showed that teeth in straight blades are more effective than teeth in curved blades [START_REF] Chong | Airfoil self noise reduction by non-flat plate type trailing edge serrations[END_REF]. Chonk and colleagues were able to reduce the noise with non-flat teeth. The effects of the tooth on all blades are not the same and in some cases it causes an increase in noise [START_REF] Jones | Numerical investigation of airfoil self-noise reduction by addition of trailing-edge serrations[END_REF]. Haag et al., by investigating the noise on a 1 MW turbine, concluded that the noise reduction is up to a frequency of less than 1500 Hz and the noise increase is above 2000 Hz [START_REF] Haag | Noise reduction of a 1 MW size wind turbine with a serrated trailing edge[END_REF]. Jones and Sandberg investigated the effect of short teeth on noise reduction and found that short teeth reduce noise at low frequencies, but long teeth reduce noise at all frequencies. Because the shape of the teeth depends on the geometry and flow of the airfoil, therefore, in the blades where the angle of attack and chord length are variable, these teeth must be accurately calculated [START_REF] Jones | Direct numerical simulations of noise generated by the flow over an airfoil with trailing edge serrations[END_REF].

Conclusion

The proposed solutions to reduce the noise pollution of turbines are very few and finding an effective solution for this problem requires much more research. One of the proposed solutions is changing the geometry of the blade, which is not applicable in many cases because changing the geometry of the blade will affect the aerodynamic performance of the wind turbine and its production power. Another solution is to use teeth on the trailing edge of the blade, which requires more research. Most of the research in this field has been done on fixed vanes, which cannot take into account the three-dimensional effects of the flow and rotation of the vane. Another solution is to taper the turbine, which can be done by using a hinge at the root of the blade. Blade taper requires the use of a control system to determine the appropriate angle in different working conditions. It should be noted that so far little research has been done on the use of conical turbines. In this research, experimental and semi-experimental models have been used to simulate noise pollution, which are not highly accurate, and in addition, all mechanisms of noise pollution production have not been investigated.


Mohammad Hosein Houshmandrad
email: hoseinhoushmandrad@gmail.com

Kavous Ghezelbeigloo

Identifying and ranking the causes of delays in different phases of oil industry projects in EPC contracts using TOPSIS method

Keywords: EPC contracts, delays, oil industry, rankings, TOPSIS method. 1

Delay, any deviation from scheduled agreements is affected by internal and external factors of the system. In this article, we identify and study the causes and factors affecting the delay in performing engineering projects by the method (EPC) and also rank the causes and factors based on the levels of importance and finally provide a solution to reduce delays. Also, the impact of these factors on the three main objectives of the project, namely time, cost and quality of the project, has been evaluated using the survey method and their ranking based on AHP and Topsis methods. The results show that factors such as delay in receipt of the contractor's claims by the employer, weakness of the contractor financial strength, unrealistic (low) price at the time of the tender by the contractor, only with the aim of winning have the greatest impact on delays in various phases of EPC Are. The research method is applied and the method of obtaining the data is descriptive.

INTRODUCTION

In general, most projects face delays. These delays can lead to additional costs and damages to project stakeholders, which in turn can lead to claims by groups involved in the project [START_REF] Ah | Construction delay: a quantitative analysis[END_REF]. Therefore, it is necessary to have precise and clear mechanisms for delay analysis to determine the extent of the delay, its impact on different parts and the whole project, and also to reveal the causes and causes of the delay [START_REF] Azadi Maa | Development of a forward chain approach for calculating selfdelay of project activities[END_REF]. The biggest problem of national development projects is the delay in the engineering, procurement and construction phases, and in many cases the amount of delay is so great that considering the inflation rate, the economic justification of the project is questioned; This issue becomes more important when we consider the strong dependence of the country's economy on the oil and gas industry and the effect of this industry on the growth and development of our country [START_REF] Assaf | Causes of delay in large construction projects[END_REF][START_REF] Mobasseri | Intelligent Circuit Application for Detecting the amount of Air in Automobile Tires[END_REF][START_REF] Mobasseri | Intelligent Circuit Application for Monitoring the Employees Attendance[END_REF][START_REF] Mobasseri | Impact of driving style on fuel consumption[END_REF][START_REF] Mobasseri | Traffic noise and it's measurement methods[END_REF][START_REF] Mobasseri | A Comparative Study Between ABS and Disc Brake System Using Finite Element Method[END_REF][START_REF] Habibi | Drug delivery with therapeutic lens for the glaucoma treatment in the anterior eye chamber: a numerical simulation[END_REF][START_REF] Mobasseri | Bending and Torsional Rigidities of Defected Femur Bone using Finite Element Method[END_REF][START_REF] Mobasseri | Approximated 3D non-homogeneous model for the buckling and vibration analysis of femur bone with femoral defects[END_REF][START_REF] Houshmandrad | Choosing the most optimal type of contract in infrastructure projects from the employer's point of view in the field of technical participation and getting rid of the pressures of liquidity provision[END_REF][START_REF] Houshmand | employer in the field of technical assistance and relief from the pressures of funding[END_REF]. In recent years, governments at various levels have sought to limit spending without reducing services. At the country level, various initiatives to change the role of government in asset management have been evaluated. Given the financial needs, the ministries of the countries are increasingly moving to the management of infrastructure facilities in a quasi-commercial way and are looking to discover new ways of partnerships between government and the private sector [START_REF] Arditi | Selecting a delay analysis method in resolving construction claims[END_REF]. As a result of these initiatives, many different modes of participation have emerged, many of which overlap with each other, but have a slight difference in meaning and method. The construction of ports by government agencies for investments requires an increasing effort to improve these methods, especially the bidding process and the selection of bidders, which is both financially and technically difficult. It is wetter and more expensive than the standard. The two defining characteristics for each of the project implementation methods are how the project steps are connected and also the provision of the required financial resources by the public or private sectors. Each of these different methods of implementation has different strengths and weaknesses that by selecting the strategy needed to carry out the project, the project will be successfully implemented [START_REF] Castro | A polynomial rule for the problem of sharing delay costs in PERT networks[END_REF].

STEP of CONDUCTING RESEARCH

Since the evaluation indicators of each system will be different depending on the main objectives of its creation and the important tasks expected from that system as well as the effective factors and the type of costs incurred, so to identify and rank the effective indicators of the causes of creation Delays in various phases of implementation of oil industry projects in EPC contracts The following steps are taken. After compiling the questionnaire, its reliability is first determined by Cronbach's alpha. Then, to determine the normality of data distribution, we use the Kolmogorov-Smirnov test. In order to determine the sample size (statistical population), we have used the Cochran's formula. In order to identify the eligibility of selected indicators to be included in the final questionnaire, first the initial questionnaire is prepared and analyzed by AHP method and then after compiling the final questionnaire to rank and identify the effective indicators by TOPSIS method is used [START_REF] Cheng | An application of fuzzy Delphi and fuzzy AHP on evaluating wafer supplier in semiconductor industry[END_REF][START_REF] Ding | Using fuzzy AHP method to evaluate key competency and capabilities of selecting middle managers for global shipping logistics service providers[END_REF].

3.

DATA COLLECTION METHODS

After identifying the experts and experts in this field, the questionnaires were distributed and while explaining the problem and how to fill in the questionnaires, they were interviewed. Considering that 2 questionnaires have been used in this research, it is worth mentioning that the first questionnaire was used to identify and validate the causes and factors of delay. Finally, 120 answers were received from EPC experts who have experience in attending or investing in this type of project, and based on this number of questionnaires, the main questionnaire has been developed. The questionnaire was then sent by 34 experts active in the field of consulting services, contractors, employers and investors active in the field of EPC projects, which after receiving the answers, will be finalized to the extent of The impact of each factor on the time, cost and quality of the project should be evaluated.

4.

DATA ANALYSIS

After sending the initial questionnaire, 120 received questionnaires were analyzed. The results of the initial questionnaire analysis were analyzed by AHP method among 120 questionnaires received from experts to confirm the qualifications of the indicators. Three of the indicators in the final questionnaire have been removed and the new items mentioned by the respondents, who in their opinion have the greatest impact on causing delays, have replaced them. The items mentioned by the respondents that have a great impact are described in Table [START_REF] Ah | Construction delay: a quantitative analysis[END_REF].

Table 1. Factors mentioned by the respondents to the open -ended questionnaire questions Impact rate Agent identified by respondents very much

1-Uncertainty about the status of nuclear negotiations and the continuation of sanctions and its impact on the cost of the project due to the high exchange rate very much 2-Lack of investment of professional foreign contractors in the field of EPC projects due to the lack of economic stability in Iran

Investigating the effect of effective factors in project PC delays on the probability of occurrence

Since it is not necessary to present nomenclature at the beginning of the paper, each variable or symbol used in the text must be clearly defined after its first appearance in the text. Figure 1 shows the extent to which factors affect the objectives of EPC contracts, including the time, cost, and quality of such projects. The occurrence of any of the effective factors in carrying out EPC projects of the oil company is indicated on the probability of occurrence. As it is known, factors such as weak contractor financial strength, delay in receiving the contractor's claims by the employer and unrealistically low price at the time of the tender by the contractor (only with the aim of winning the tender) have the greatest impact on the time and cost of projects They have EPC oil companies. Thus, the factors that have the greatest effect on delays in oil company EPC projects (11 most important factors) are shown in Table 4. In the next step, the numerical results of the analysis of factors affecting the delay of procurementconstruction projects using the concept of mathematical hope (PI) and in the next step to prioritize the factors affecting the delays of procurement-construction projects based on the level We discuss the importance of each factor (due to the limited number of pages of the article, the presentation of analytical tables in this section is omitted).

RANKING THE LEVELS OF IMPORTANCE OF VARIOUS FACTORS INFLUENCING THE DELAY OF PROCUREMENT PROJECTS USING THE TOPSIS METHOD

Perform the eight analytical steps of the TOPSIS method, respectively, and the final ranking of the various factors influencing the delay of procurement-construction projects will be as described in Table 6. Before that, in Table 5, we calculate the coefficient of proportionality of each of the ranking factors.

high 3 - 4 - 5 - 6 -very much 7 - 3 Provide inappropriate procedure 4 Delayed

 3456734 Hastening the opening of projects due to political and social issues and its opposite results very much Technical weakness of the employer's representative in coordination between consulting engineers and the contractor and timely resolution of technical and executive problems of the project very much Administrative bureaucracy in the employer organization very much Adherence of consulting engineers to the non-expert order of the employer, which increases time and cost. Lack of proper knowledge of the project area Table2. Final questionnaire Factors influencing the delay of procurement projects Failure to employ experienced and specialized personnel Design and engineering phase 1 Technical weakness of the employer's representative in coordination between consulting engineers and contractors and timely resolution of technical and executive problems of the project 2 Lack of proper coordination between employer and contractor (design consultant) response to the engineering department of the contractor (consultant) to the required changes in the plans and ... during the implementation of the project (lack of coordination and necessary cooperation of the engineering department with the implementation department) 5 Assignment of the project to a company formed through a consortium of several contractors 6 Failure to determine the exact amount of goods required or missing goods in the list provided by the engineering department for the project procurement department 7 Errors and errors in design (items such as: errors in announcing the size, type and material of items listed in the map, etc.) 8 Delay in starting the activities of the engineering department due to the prolongation of the recruitment process and the preparation of the project engineering team 9 Delayed response to the client's engineering department for required changes to project drawings and documentation Uncertainty over the status of the nuclear talks and the persistence of sanctions and their impact on the cost of the project due to the high exchange rate Procurement phase Lack of investment of professional foreign contractors in EPC projects due to lack of economic stability in Iran Administrative bureaucracy in the employer organization Failure to hire specialized and experienced personnel in the contractor's logistics and trade team Sanctions on Iran by some countries The impact of government programs and laws on the activities of the supply sector (for example, preventing the import of a specific product that is required by the project) Unpredictability of inflation rate and increase in prices of materials compared to the time of rate submission and estimation of project costs Submission of unrealistic (low) prices at the time of the tender by the contractor, for the sole purpose of winning the tender Delay in receipt of contractor claims by the employer Contractor financial weakness Exchange rate change Procurement of materials without proper quality Lack of preparation of materials required for the project based on the list of engineering (items such as: insufficient supply and in accordance with BOM) Failure to follow the issues and problems of the product supply phase by project managers Delays in delivery and transportation of goods by suppliers and depreciation / breakdown of materials during transportation Restricting the list of suppliers of materials (Vendor List) by the National Oil Company and forcing them to supply materials and materials Selection of inexperienced and unsuitable builders and suppliers by the contractor Construction and implementation phase Extension of account opening time and activation of letter of credit (LC) Problems of customs clearance and prolongation of the clearance process Failure to hire specialized and experienced staff by the contractor Poor performance of the Technical Inspection Office Command change in work Selection of second-hand contractors and inexperienced employees due to their low wages by the contractor Improper planning as well as not using proper project control methods Involvement of employer project managers and experts in more than one project and their lack of sufficient focus in this project Lack of sufficient financial resources as well as spending the project budget on activities other than the project mentioned by the contractor Delays in the project due to contractor tools, equipment and supplies Unfavorable weather conditions such as rain, wind, dust, etc. Delay in pursuing issues and solving problems (inside and outside the organization) by the employer project managers Lack of contractor manpower to perform all activities mentioned in the schedule, as well as inappropriate and inefficient allocation of personnel in different areas of work by the contractor Adherence of consulting engineers to the non-expert order of the employer, which increases time and cost Poor job description provided by the employer (non-transparency of the items mentioned in the job description and also incomplete job description) Risk of project environments and delays in securing the site for project implementation Performing activities outside the regulated job description and allocating people / resources / budget to these activities Lack of proper knowledge of the project area Haste in opening projects due to political and social issues and its opposite consequences Fuel supply problem (for cars, diesel welding engine, air compressor, etc.) Delay in decision-making and assignment of tasks to the land opponents of the project site by the employer OFTEN THE MOST USEFUL AND AT THE SAME TIME THE FIRST STEP IN DATA ORGANIZATION IS TO SORT THE DATA ACCORDING TO A LOGICAL CRITERION AND THEN TO EXTRACT THE CENTRAL INDICATORS AND SCATTERING AND IF NECESSARY CALCULATE THE CORRELATION BETWEEN THE TWO CATEGORIES OF INFORMATION AND USE MORE ADVANCED ANALYSIS SUCH AS FORECASTING. FOR THIS PURPOSE, CENTRAL INDICATORS ARE CALCULATED. CENTRAL INDICATORS ARE IN THREE TYPES OF VIEW (MODE), MEDIAN (MEAN) AND MEAN (MEAN), EACH OF WHICH HAS ITS OWN APPLICATION. IN RESEARCH WHERE THE SCALE OF DATA MEASUREMENT IS THE MINIMUM DISTANCE, THE AVERAGE IS THE BEST INDICATOR. THEREFORE, IN TABLE 3, DESCRIPTIVE STATISTICS ARE PRESENTED IN FULL.

Table 4 .

 4 Factors with the greatest impact on the delay of procurement-construction projects (10 most important factors) The main factors influencing the delay of procurement-construction projects Weakness of the contractor x20 Haste in opening projects due to political and social issues and its opposite consequences x46 Submission of unrealistically low prices at the time of the tender by the contractor (for the sole purpose of winning the tender x18 Delay in receipt of contractor claims by the employer x19 Lack of preparation of materials required for the project based on the list of engineering (items such as: insufficient supply and in accordance with BOM) x23 Procurement of materials without proper quality X22 Lack of sufficient financial resources as well as spending the project budget on activities other than the project mentioned by the contractor x36 Involvement of employer project managers and experts in more than one project and their lack of sufficient focus in this project x35 Delays in the project due to contractor tools, equipment and supplies x37 Adherence of consulting engineers to the non-expert order of the employer and as a result increase time and cost x41 4.

Figure 1 .

 1 Figure 1. The effect of factors affecting the objectives of EPC contracts, including time, cost and quality

Table 3 . Descriptive statistics of identified factors in causing delays in oil company EPC projects Descriptive Statistics

 3

	Factor	Number of variables	minimum maximum	Average	The standard deviation
	x1	170	1.00	2.00	1.1765	.38263
	x2	170	2.00	3.00	2.5588	.49836
	x3	170	1.00	3.00	1.8235	.41957
	x4	170	2.00	4.00	2.4485	.51381
	x5	170	1.00	2.00	1.3088	.46372
	x6	170	2.00	4.00	2.4779	.51592
	x7	170	1.00	2.00	1.3309	.47227
	x8	170	1.00	3.00	1.8971	.35023
	x9	170	2.00	3.00	2.6397	.48186
	x10	170	1.00	2.00	1.1471	.35547
	x11	170	2.00	3.00	2.7059	.45733
	x12	170	2.00	4.00	2.7500	.45134
	x13	170	1.00	2.00	1.4632	.50049
	x14	170	2.00	4.00	2.2868	.46996
	x15	170	2.00	4.00	2.3971	.50596
	x16	170	2.00	3.00	2.3456	.47732
	x17	170	2.00	4.00	2.4559	.51450
	x18	170	4.00	5.00	4.4559	.49989
	x19	170	4.00	5.00	4.5000	.50185
	x20	170	4.00	5.00	4.7500	.43461
	x21	170	1.00	3.00	1.8235	.41957
	x22	170	4.00	5.00	4.1912	.39468
	x23	170	4.00	4.00	4.0000	0.00000
	x24	170	1.00	2.00	1.5000	.50185
	x25	170	1.00	3.00	1.7794	.43361
	x26	170	2.00	4.00	2.7794	.43361
	x27	170	2.00	4.00	2.8824	.45638
	x28	170	1.00	3.00	1.7059	.47325
	x29	170	2.00	4.00	2.2059	.42370
	x30	170	3.00	4.00	3.2206	.41618
	x31	170	1.00	3.00	1.6691	.48770
	x32	170	1.00	2.00	1.0809	.27366

Table 4 ,

 4 the highest probability of occurrence in terms of level of importance is X20 and indicates the financial weakness of the contractor and the lowest level of importance is X32 and is a command to change.

Table 4 . Calculation of the proportionality coefficient of each of the ranking factors Ranking factors Proportion coefficient and importance of effective factors in delaying procurement- construction projects

 4

	Impact on quality	19400
	Impact on time	19522
	Impact on cost	19521

Table 6. The final result of ranking the various factors influencing the delay in oil company EPC contracts

CONCLUSIONS

In this article, the causes and factors affecting the delay in performing engineering projects by the method (EPC) method, their ranking based on the levels of importance as described in Table 6. Also, the impact of these factors on the three main objectives The project means that the time, cost and quality of the project have been evaluated. Using the results of this study, companies active in the field of EPC projects, during the project, by reducing the incidence of the above factors, will be able to reduce additional project time, prevent additional costs and increase the quality of work 6.


Graine, émergence de la radicule Seed, hypocotyl and cotyledons growing towards soil surface Graine, hypocotyle et cotylédons en croissance vers la surface du sol

The BBCH code of Camellia sinensis identifies the stages of phenological development of the tea plant resulting from the observation and needs of tea growing, the first version of which is proposed in the book "Théiers, théieraies, feuilles de thés" (Tea Plants, Tea Orchads, Tea Leaves) Alain guerder, ed. Écohameau de Barthès, 2021, 240 p. (isbn 978-2-9580-3750-5) Le code BBCH du Camellia sinensis identifie les stades de développement phénologiques du théier issu de l'observation et des besoins de la théiculture dont la première version est proposée dans l'ouvrage "Théiers, théieraies, feuilles de thés" Alain guerder, éd. Écohameau de Barthès, 2021, 240

Flower

  closed, the petals have their final size and are still closed, the outer ones have a green trace, the internal organs of the flower are not visible Fleur fermée, les pétales ont leur taille définitive et sont encore fermés, les externes ont une trace verte, organes internes de la fleur non visibles Half-opened, the petals are half-open. internal organs are visible. Cup-shaped flower Mi-éclose, les pétales sont mi-ouvertes. les organes internes sont visibles. Fleur en forme de coupe Open, beginning of anthesis, horizontal petals, brightly colored stamens, fragrant flowers emitting the maximum number of molecules, pale yellow stigmas, slightly swollen and secreting a small amount of mucus Épanouie, début de l'anthèse, pétales horizontals, étamines de couleur vive, fleurs odorantes émettant le maximum de molécules, stigmates jaune pâle, légèrement enflés et sécrétant une petite quantité de mucus Post-flowering, the stamens are brown Post-épanouissement, les étamines sont brunes End of flowering the petals are withered, the stamens are brownish, the anthers no longer release pollen and shrivel up Fin de floraison les pétales sont flétris, les étamines sont brunâtres, les anthères ne libèrent plus de pollen et se ratatinent Fall of the corolla, the petals and the stamens have fallen, the sepals persist and envelop the ovary, the stigma fades and blackens Chute de la corolle, les pétales et les étamines sont tombées, les sépales persistent et enveloppent l'ovaire, le stigmate se fanent et noirci 10 % des bouquets sont passés par le stade épanouissement (605) 50 % des bouquets sont passés par le stade épanouissement End of flowering, all the flowers of all the bouquets have fallen. Fruit set visible Fin de floraison, toutes les fleurs de tout les bouquets sont tombées. Nouaison visible

BBCH Camelia sinensis-2023.05

	0	Germination, sprouting, bud development	Germination, levée, développement du bourgeon
		Seed, tegument is split	Graine, le tégument est fendu
		Seed, radicle emerge

des feuilles de la tige principale

  10The true leaf is differentiated and has not started unrolling La vraie feuille est différenciée et n'a pas commencé son déroulement Unfolding, the leaf begins to unfold Déroulement, la feuille commence à se dérouler Leaf unfolded and not starting to growth Feuille ayant fini son déroulement et n'ayant pas commencé à grandir Leaf size less then 50% of its final size Feuille d'une taille inférieure à 50 % de sa taille définitive Leaf at 50 % of final size Leaf of a size between 50 % and less than ⅔ (66%) of its final size Feuille d'une taille entre 50 % et moins de ⅔ (66 %) de sa taille définitive Leaf opened between ⅔ and almost 100% of its final size Feuille ouverte à plus de ⅔ ou à presque 100 % de sa taille définitive

	1n 11	1	1nx	p. Plante, au repos, bourgeon complètement fermé, à l'arrêt ou dormant couvert par (isbn isbn 978-2-9580-3750-5) Développement Leaf at final size Seed, dormancy Cutting, fresh Plant, dormancy, leaf bud closed, in resting period or dormancy and covered by green scales (banjhi) Feuille à sa taille définitive Graine, dormante So on leaf n at stage x Ainsi de suite feuille n au stade x Bouture, juste prélevée The 1st true leaf begins to unfold des cataphylles (banjhi) The 1st leaf at 50% of its final size
	18 19			Seed, imbibition beginning. Cutting, wound healing, timing of hormone application Plant, beginning of bud swelling cataphylls elongate (bud break) The 8th and last possible leaf begins to unfold 8th leaf reach final size Seed, small swelling visible at one end All leaves are mature, reaching full size	Graine, début de l'imbibition Bouture, cicatrisation, moment de l'application d'hormones Plante, début du gonflement du bourgeon, les cataphylles s'allongent La 8ᵉ feuille à sa taille définitive (débourrement) Graine, petit renflement visible à une extrémité Toutes les feuilles sont matures, ayant atteint leur taille définitive
				Cuttng, callus formation begins	Bouture, formation du cal
				Seed, imbibition complete	Graine, imbibition achevée
				Cutting, end of bud swelling	Bouture, fin du gonflement des bourgeons
				Plant, cataphylls have their maximum size, the leaves are not visible	Plante, les cataphylles ont leurs taille maximum, les feuilles ne sont pas visibles
				(mature bud)	(bourgeon mature)
				Seed, elongation of radicle, formation of root hairs.	Graine, élongation de la radicule, apparition des poils absorbants
				Cuttings, root branching	Bouture, les racines se ramifient
				Seed, cotyledons and hypocotyl emerge from the seed	Graine, cotylédons et hypocotyle émergent de la graine
				Plant, buds open, cataphylls begin to separate,	Plante, les bourgeons s'entrouvrent, les cataphylles commencent à se séparer,
				leaf tips are visible	l'extrémités des feuilles est visible
				Emergence. Seed, sprout emerges from the soil surface Plants, the ends of the leaves exceed the cataphylls by a few mm	Émergence. Graine, la pousse émerge de la surface du sol Plantes, l'extrémités des feuilles dépassent les cataphylles de quelques mm

Stage before 119 is an immature shoot never to be harvested (arimbu)

Le stade avant 119 est une pousse immature à ne jamais récolter (arimbu) 2 Formation

of side shoots Formation des pousses latérales

  Feuille à 50 % de sa taille finaleLa 1 e vraie feuille commence à se dérouler La 1 e feuille est à 50 % de sa taille finale The 1st leaf at its final size (mother-leaf) La 1ᵉ feuille à sa taille définitive (feuille-mère) La 8 e et dernière feuille possible commence à se dérouler Stages 104, 106 and 107 of the last leaf before the shoot comes to rest correspond to the stages identified for the picking so-called "expanded aspect" (kāimiàncǎi) typical of blue teas Les stades 104, 106 et 107 de la dernière feuille avant que la pousse ne se mette en repos correspond aux stades repérés pour la cueillette dite "aspect déployé" (kāimiàncǎi) typique des thés bleus On average when a leaf is at stage 109, the leaf above is at ~105-108, the one still above is at ~102-105 and the 3ᵉ after is at 101 Floral initiation, the state change is not visible Initiation florale, le changement d'état n'est pas visible Differentiation, bud visibly become a flower bud covered with green bud scales Différenciation, bourgeon visiblement bouton floral couvert de pérules vertes Mature bud, reached its final size and buds scales are still closed and green Bouton mature, a atteint sa taille définitive, pérules encore fermées et vertes Bud scales spread apart, ends just spread apart, the color of the petals is visible Pérules écartés, les extrémités s'écartent juste, la couleur des pétales est visible

	4		Main shoot leaf development Development of vegetative propagation organs	Développement des organes de propagation végétative
			The stem is not lignified	La tige n'est pas lignifiée
			Beginning of lignification	Début de la lignification
			The stem is semi-lignified. best time to take cuttings	La tige est semi-lignifiée. moment idéal pour prélever des boutures
			The stem is completely lignified	La tige est entièrement lignifiée
	5		Inflorescence emergence (cyme)	Apparition de l'inflorescence (cyme)
	6		Flowering, anthesis	Floraison, anthèse
			(Flower opening stages)	(Stades d'ouverture de la fleur)
		601	The petals begin to open, the internal organs are not visible	Les pétales commencent à s'ouvrir, les organes internes ne sont pas visibles
		603
		605		Quand une feuille est au stade 109, la feuille au-dessus est à ~105-108,
				celle encore au-dessus est à ~102-105 et la 3ᵉ après est à 101
		606
		607 608 609	End of blooming, the petals are browned and their margins rolled up From top to bottom the leaves are named: last leaf, flowering pekoe, orange pekoe, pekoe, souchong, congou, bohea, mother leaf (the base leaf is always called mother leaf regardless of the number of leaves in the mature stem)	Du sommet à la base les feuilles sont nommées : Fin d'épanouissement, les pétales sont brunis et leurs marges enroulées dernière feuille, flowering pekoe, orange pekoe, pekoe, souchong, congou, bohea, feuille-mère (la feuille de la base se nomme toujours feuille-mère quel que soit le nombre de feuille de la tige mature)
		60nx Flowers of the bunch n, counting from the base to the top of the shoot, at stage x Fleurs du bouquet n, en comptant de la base au sommet de la pousse, au stade x
	20 22 6n 23 2n	6010 6011 6nx 2nx 615 655 695 699	Undeveloped axillary buds The 1st flowers of the 1st bouquet, the lowest on the shoot, begin to open Growth of 2nd order shoots The petals of the 1st bouquet are beginning to open, internal organs not visible The cataphylls of the 2nd order axillary bud elongate (Overall flowering stages of the plant) Shoots of 2nd order at finale size Growth of 3d order shoots So on shoots of order n at stage x Shoots of 2nd order at 50 % of full size 10% of bouquets went through the blooming stage (605) 50% of bouquets went through the blooming stage All bouquets have gone through the blooming stage	Les 1e fleurs du 1e bouquet, le plus bas sur la pousse, commencent à s'ouvrir Bourgeons axillaires non développées Les pétales du 1e bouquet commencent à s'ouvrir, organes internes non visibles Croissance des pousses de 2e ordre (Stades globales de floraison de la plante) Les cataphylles du bourgeon axillaire de 2ᵉ ordre s'allongent Ainsi de suite pousse de l'ordre n au stade x Pousse de 2 e ordre à 50 % de sa taille finale Pousse de 2 e ordre à sa taille définitive Tous les bouquets sont passés par le stade épanouissement Croissance des pousses de 3 e ordre
	3		Main shoot development	Développement de la pousse
	31		Start of shoot growth, the axis is visible between the cataphylls	Début de la croissance de la pousse, l'axe est visible entre les cataphylles
	35		The stem has reached 50% of its final length	La tige a atteint 50 % de sa longueur finale
	39		The sem has reached its final length	La tige a atteint sa longueur définitive

7

Fruit development Développement des fruits 70 (Fruit development) (Développement du fruit) Fruit set, the fruit has visibly started to develop Nouaison, le fruit a visiblement commencé à se développer The fruit reaches 50% of its final size 70nx

Fruits of the bunch n, counting from the base to the top of the shoot, at stage x Fruits du bouquet n, en comptant de la base au sommet de la pousse, au stade x 7010 7015

The fruits of the 1st bunch have 50%


MICRO PIN INTERACTION IN FIN VICINITY AT SUPERSONIC CONDITIONS 48 th APPLIED AERODYNAMICS SYMPOSIUM

INTRODUCTION

At supersonic flight conditions, shock waves strongly change pressure repartition on any solid surface. This fact makes it possible to imagine a way to steer flying vehicles. The main idea in this study was to use small disturbances to generate shocks. Lift forces on a body are mainly due to pressure applied on large surfaces. This is why a finned configuration was chosen for this paper.

Here are presented the results of numerical simulations and wind tunnel experiments of pin interaction with fins on the Basic Finner reference aerodynamic architecture at Mach number 2.

INTEREST OF THE STUDY

Supersonic flight addresses the future of engineering flight studies, as well for civil as for military applications. At supersonic conditions, rudder torque might make steering design quite tricky. It would be better to change pressure repartition on a surface thanks to a small additional device than moving the surface itself. As described previously, supersonic conditions lead to shock waves formation, related to high pressure changes. The goal is to use a small device dedicated to shock wave generation. This was achieved thanks to a cylindrical pin attached to the body surface. This concept was early developed by Massey and Silton [START_REF] Massey | Design and Wind Tunnel Testing of Guidance Pins for Supersonic Projectiles[END_REF], [START_REF] Silton | Integrated Numerical and Experimental Investigation of Actuator Performance for Guidance of Supersonic Projectiles[END_REF]. In order to evaluate the aeroballistic performances of the concept, it is of the highest importance to achieve a parametric study concerning the positioning, size and shape of the pin relatively to the reference model which has been chosen to be the wellknown Basic Finner (described in the following). Hereby, the observed parameter is the position of the pin. Shape, size and Mach number are fixed. In order to increase the results validity, we compared numerical simulation and wind tunnel results. Numerical results were obtained with ANSYS CFX, while wind tunnel tests were conducted with an aerodynamic balance and pressure sensitive paints (PSP).

REFERENCE MODEL

The reference model used in this study is the Basic Finner, which has been measured many times. The DRDC team completed an extensive free flight campaign [START_REF] Dupuis | Aeroballistic Range and Wind Tunnel Tests of Basic Finner Reference Projectile from Subsonic to High Supersonic Velocities[END_REF]. This finned model is of a very simple shape. Its length to calibre ratio has a value of ten, which produces a stable static margin.

Figure 1. Basic Finner

To make them comparable, wind tunnel model and numerical simulations were performed with the same size, Mach number and Reynolds number. Due to the S20 test section the model caliber has been set to 20mm.

WIND TUNNEL FACILITY

The S20 wind tunnel situated at ISL (Saint Louis, FRANCE) in which the experiments were conducted, is a blow down facility, supplied with air pressure by storage under 250 bar. The Mach number in the 20x20cm² test section, can reach a range between 1.4 and 4.4. The turbulence rate is below a few percents.

Figure 2. S20 wind tunnel

An aerodynamic balance form the Abble company was used due to its high reproducibility and its low hysteresis quality. The measurements were processed to obtain the six static aerodynamic coefficients for each configuration.

To confirm the experiments validity, a Schlieren image was also used to visualize the shock wave produced by the model tip. Those waves reflect on the wind tunnel walls, which may dramatically change the aerodynamic forces on the model. The Schlieren photography allowed confirming that the wall proximity did not influence the results and could eventually give a clue for potential unexplained phenomena, which was not the case. The S20 wind tunnel has been used at Mach number 2, with a total temperature of 300K and a generating pressure of 4.5 bar.

GOAL ANALYSIS

The pin steering concept was exposed by Silton and Massey [START_REF] Silton | Investigation of Actuator Performance for Guiding Supersonic Projectiles[END_REF]. In 2008, they reported drag increase between 7% and 15% at Mach 2 for the shortest pins, so that the device would only be dedicated to short range use. It was decided at ISL to study relatively smaller pins to decrease the induced drag. Indeed, the resistance forces should occur directly on the pin itself, by pressure difference between leeward and windward sides. That is why the wind projected pin surface should be as small as possible. In Eq. 1, let us define a criteria we call the device benefit ratio, based on the pin related side force ∆F s (in the vehicle frame) to the axial additional force ∆F a generated by the pin. This benefit ratio R d should be maximised under constraint of |∆F s | being enough for vehicle guidance. This ratio is interesting because it firstly can be compared to the vehicle proper lift to drag ratio (Eq. 2).

a F s F vehicle R = (2)
Secondly considering the lateral velocity correction aimed with the system, it is time related, m being the vehicle mass and V s the lateral velocity. If we consider a constant additional side force ∆F s and axial force ∆F a during ∆t, the additional velocity compared to the vehicle proper velocity is:

m F m F a s . t a V . t dt . m s F s V ∆ ∆ ∫ ∆ = ∆ ∆ = ∆ = ∆ (3) pin a s R a V s V F F = ∆ ∆ = ∆ ∆ (4)
Eq. 4 means that the axial velocity loss for a targeted additional lateral velocity is directly related to the benefit ratio. From Eq. 3, one can say that only the needed time to obtain the lateral velocity correction is depending on the |∆F s |, which must thus be constrained. One goal of the study would then be to establish if a pin size decrease would increase the benefit ratio and if we can keep guidance capability.

PINNED MODEL

Basic Finner

The Basic Finner model was set to a caliber of 20mm, for a total length of 200mm. The pin is a small cylinder compared to the Basic Finner as it can be seen on Fig. 3 and4. Its length is 3mm and its diameter is 1.5mm. A set of positioning holes were drilled during the manufacturing, so that the pin can be screwed in any of them precisely. The unused holes are filled in with plaster and polished before the experiments. The Reynolds number based on vehicle length for our experiments has been calculated to be 10.9 x 10 6 .

Pin position

In the following lines, we will refer to different positions of the pin on the vehicle surface. Due to manufacturing needs, we chose a set of five lines along which the pin could be placed. As shown in fig. 5, line #1 is situated next to the vertical fin, Z being the vertical direction. Line #5 is situated next to the horizontal fin, Y being the horizontal and lateral direction. X is the vehicle axis, oriented in the flow direction.

WIND TUNNEL RESULTS

In the Basic Finner configuration, drag is mainly due to base pressure, imposed by the wake and base flow. In the wind tunnel, the model is held by a sting which size is not negligible compared to the caliber. As a consequence, drag has been measured but will not be presented here. This section will hold a first part containing information about aerodynamic coefficient, and a second one about angular balance.

Aerodynamic coefficients

Compared to the reference body without actuator, using a pin is not far from superimposing a coefficient offset on the torque coefficients. In addition, variation of the normal force at 0° angle of attack (AoA) is small, as it can be seen in Fig. 8.

That is why fig. 9, 10 and 11 represent coefficient offset at 0° angle of attack. Roll torque offset is indeed the roll torque itself, because the reference configuration is axisymetrical. Line 3 is supposed to generate no roll torque, when the other lines should be symmetric, which is almost the case.

Angular balance

As seen before, neither Cz α has not been dramatically changed by adding a pin to the Basic Finner, nor has been the yaw and pitch coefficients Cm α and Cn α . As a consequence the vehicle tends to get an angular balance that is not 0° anymore. From a linear point of view, as far as small angles are involved, Fig. 9 and 10 can be directly converted into an angular balance. This is shown in Fig. 12 and 13.

Those two small angles can be converted into a total aerodynamic angle which is represented in Fig. 14. It can be observed that position 7-1 and 7-5 are the best positions for an angular control with an angle of 0.4°. This will be explained in the following section.

NUMERICAL SIMULATIONS

Experimental reference results

Reference Basic Finner has been computed first. To start, we considered the reference report on Basic Finner [START_REF] Dupuis | Aeroballistic Range and Wind Tunnel Tests of Basic Finner Reference Projectile from Subsonic to High Supersonic Velocities[END_REF].

Cx 0 Cz α Cm α 0.554 11.4 -25.2

Table 1. Free flight measurement results [START_REF] Dupuis | Aeroballistic Range and Wind Tunnel Tests of Basic Finner Reference Projectile from Subsonic to High Supersonic Velocities[END_REF] at Mach 2 At Mach 2, the main aerodynamic coefficients can be found in Tab. 1. Those are the interpolated data from the free flight.

Pin orientation

During the numerical study, pin orientation has been changed to see roll angle influence. Fig. 17 shows four configurations in a front view. Configuration 1 is so called "roll angle 0°", configuration 2 is "roll angle 90°", configuration 3 is "roll angle 45°" and configuration 4 is "roll angle -45°".

Figure 17. Pin configurations

Simulation validation

The first simulated case is the Basic Finner without pin. Compared to the reference report on Basic Finner [START_REF] Dupuis | Aeroballistic Range and Wind Tunnel Tests of Basic Finner Reference Projectile from Subsonic to High Supersonic Velocities[END_REF], drag is over estimated: CFX results lead to Cx value of 0.59 when 0.55 were awaited. This is not surprising as far as the pressure based solver was set to a stationary RANS simulation. Numerical simulation value of Cz α reaches 11.0 and Cm α is -21.4. This last value is a bit too small, but should be compared to our wind tunnel tests in Tab. Concerning Cx increase, Fig. 18 shows that it is kept below 3%, which is awaited as far as pin size remains small relatively to the Basic Finner caliber. values. This offset applies at the rear of the body, which causes also a torque offset, as it can be seen in Fig. 21 to 23. Fig. 21 shows the roll torque coefficient is mainly an offset with a slight angle of attack influence. It seems logical that only one pin creates a roll torque. This could be minimised by using another pin having a contrary effect.

CONCLUSION

In this study, we have shown that numerical simulation is reliable enough to investigate pin positioning and system efficiency. A total balance angle of 0.4° can be obtained by using pin 7-1. For a Cz α value of 11.0, the benefit ratio for this device is about 5.9. The benefit ratio would only be 2.95 for pin 1-5 (balance angle of 0.2°). The system shows a good efficiency for a guidance mechanism, without increasing drag too much.

Figure 3 .

 3 Figure 3. Basic Finner wind tunnel model

Figure 4 .

 4 Figure 4. Fins compared to pin size

Figure 5 .

 5 Figure 5. Axis orientation and pin position

Figure 6 .

 6 Figure 6. Pin axial position

Figure 8 .Figure 10 .Figure 11 .

 81011 Figure 8. Relative variation of normal force (∆Cz α /Cz α )

Figure 14 .

 14 Figure 12. Yaw angle offset

7. 1 .

 1 Numerical configuration ANSYS CFX solver has been used to calculate configuration 7-1. The chosen turbulence model is Shear Stress Transport (SST). Boundary conditions have been set to the ISL wind tunnel specifications. The mesh has been created with ANSYS Mesher and is unstructured. It is made of 140349 nodes and 4452328 cells. The boundary layer is taken into account with 17 refined cell layers (first one being 10µm) with a grow rate of 1.3. As displayed in Fig.15, the mesh was refined in pin, fin and tip proximity as well as in the wake in order to better capture the flow modification around the pin.

Figure 15 .

 15 Figure 15. Vertical mesh cut around Basic Finner

7. 5 .

 5 Fig. 18 to 23 represent aerodynamic coefficient change relatively to Basic Finner without pin as a function of the angle of attack. For each configuration, three angles have been considered: -3°, 0° and +3°.Concerning Cx increase, Fig.18shows that it is kept below 3%, which is awaited as far as pin size remains small relatively to the Basic Finner caliber.

Figure 20 .

 20 Figure 18. ∆C x

Figure 23

 23 Figure 21. ∆Cm x

Figure 25 .

 25 Figure 25. Pressure simulation on the fins Fig. 26 is the result of a pressure sensitive paint experiment. The map is scaled as Fig. 25. Fig. 25 and 26 represent the pressure repartition around the pin for a roll angle of 0° and an angle of attack of 3°. It is possible to notice the overpressure in front of the pin and on the windward side of the horizontal fin. The

Figure 26 .

 26 Figure 26. PSP result @ 3° AoA

  2.

				[3] free flight tests, velocity may have
				decreased, thus changing Cm α value.
		Cx 0	Cz α	Cm α
	DRDC	0.554	11.4	-25.2
	ISL S20	/	10.3	-22.6
	Simu	0.59	11.0	-21.4
	Table 2. Basic Finner coefficients comparison
		at Mach 2
	Though not perfect, numerical simulation
	parameters seem to give acceptable results.
	The difference with the DRDC experimental
	value might be explained by a different
	Reynolds number of 13.7x10e6. In addition,
	Cm α decreases quickly with Mach number
	decreasing towards Mach 1. During the DRDC

ACKNOWLEDGEMENTS

The authors would like to thank warmly the French DGA for sustaining this study inside of a contract called PEA MANEGE, under number 2011 92 00 20. The authors would also like to mention the fruitful partnership between ISL, Nexter Munitions and ONERA who are working together on this contract. Last but not least, the wind tunnel team should be thanked for their proficiency.