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Open Access Article

1 - Ozone Concentration and Meteorological Parameters Alternations Investigation in Air Quality Control Company to Aqdasieh Station in 7 Months (from Oct. 2007 to Apr. 2008) in Tehran
Mansour Ghiasodin Leila Sourati

In this research measuring ozone concentration in air quality control Company at Aqdasieh station,and meteorological parameters at Resalat station, was compared and investigated. This investigationwas performed for 7 months (from Oct. 2007 to Apr. 2008). The average dai More

In this research measuring ozone concentration in air quality control Company at Aqdasieh station,and meteorological parameters at Resalat station, was compared and investigated. This investigationwas performed for 7 months (from Oct. 2007 to Apr. 2008). The average daily Ozone concentrationshowed the least quantity of Ozone in early morning and late night air. Comparing the sunshineradiation with variation of Ozone concentration indicated that these two items have direct relations.Increasing the sunshine radiation concludes the increasing of photochemical activity and consequentlyincreasing the Ozone concentration. Investigating the monthly average Ozone concentration showedthat the least registered amount of Ozone was during these 7 months of measurement in Azar(November) and the most registered amount of Ozone occurred in Farvardin (April). The mostimportant factor of main increasing happened in April and in the solar radiation and photochemicalactivities. Manuscript profile

Open Access Article

2 - Heat loss reduction using ceramic micro-particles in paint of the inner walls of a room with radiation cooling panel
Ghanbar Ali Sheikhzadeh Ali Akbar Azemati Armin Saraei

Introduction and Aim Limited resources and the need for energy conservation have made the use of energy loss preventive thermal insulations, like the paints containing micro mineral particles, an economic option in different industries and buildings. The aim of the curr More

Introduction and Aim Limited resources and the need for energy conservation have made the use of energy loss preventive thermal insulations, like the paints containing micro mineral particles, an economic option in different industries and buildings. The aim of the current study is to investigate the effect of modern insulation, such as paints with ceramic micro-particle in internal walls of a room with radiative cooling panels, on energy consumption.  Method In the present study, to investigate the flow field and temperature distribution in a room with a wall of radiation cooling, a three-dimensional cavity has been simulated with different boundary conditions. The effect of coating with a paint containing ceramic micro-particles, ordinary acrylic paints and no paint in different states of changing the boundary conditions, such as changes in wall temperature and absorption coefficient on a room with wall cooling radiation has been studied and the results were compared. Findings Using the computer code, the interior surface temperature is obtained for different boundary conditions and used as a boundary condition for simulation. In case of using wall radiative cooling panels, room temperature is in the comfort zone in all cases, and the lowest temperature occurs when using paints with ceramic micro-particles in the interior surfaces of the room. Discussion It was observed that the coating containing ceramic micro-particles acted as a thermal insulation and reduced energy consumption by about 22% . Manuscript profile

Open Access Article

3 - The role of slope shape roofs in heating energy consumption Based on thermal comfort
Ali Sharghi Nazanin Azimi Fereidani

10.22034/jest.2017.10655

Background and Objective: In the past, thermal comfort was created through the design of buildings and a handful of construction equipment. Selection of appropriate crust form was one of the noteworthy methods in architecture. Such circumstances were changed in 1960s. H More

Background and Objective: In the past, thermal comfort was created through the design of buildings and a handful of construction equipment. Selection of appropriate crust form was one of the noteworthy methods in architecture. Such circumstances were changed in 1960s. Heating, cooling and lighting supply of buildings by mechanical equipment and the use of fossil fuels became pivotal aspect. In the past years following the energy crisis created in this way and environmental pollution, again the best case of heating and cooling, became the accordance to building design and use of clean energy. In these circumstances, appropriate and followed by that reduction of energy consumption of buildings. Among these components, roofing, which plays a fundamental role in thermal exchange, is often overlooked. Method: In this article, research method is done based on computer modeling and simulation by Revit 2014 and energy plus with version of 8.1.  Findings:So, ahead research intends to discuss in the mountainous of Karaj comparison between the four dominant type of roof including flat, one-way, two-way and four-way with the different angles. Its target is to achieve the optimum form and a roof sloping angle in this region based on the average radiant temperature, the man factors of thermal comfort. Discussion and Conclusion:  Results of Analysis of simulated models, shows optimal roof and its most appropriate angle in the sloping roof with constant floor area according to the average mean radiant temperature in the studied model.  Manuscript profile

Open Access Article

4 - Design and simulation of a wired antenna with a new structure and compare it with a conventional unipolar antenna of equal length
Firooz Mohsenifard Ebrahim Abiri Jahromi Abbas Fazel Zakeri

In this paper, a wired antenna with a new structure for the central frequency of 15 MHz is designed and simulated. In addition to being shorter than the wavelength, this antenna has a high radiant resistance and low imaginary resistance compared to a unipolar antenna of More

In this paper, a wired antenna with a new structure for the central frequency of 15 MHz is designed and simulated. In addition to being shorter than the wavelength, this antenna has a high radiant resistance and low imaginary resistance compared to a unipolar antenna of equal length. Also, for high efficiency and maximum bandwidth in the frequency range of 10 to 25 MHz, the dimensions of the antenna have been optimized.  S-NEC software is used to design and simulate this antenna, which is one of the specialized software in this field. It is also possible to increase the dimensions of the antenna by a certain ratio, for example 1000, and therefore the operating frequency of the antenna decreases by the same ratio, such antennas that work in the VLF band are used for special purposes. Manuscript profile

Open Access Article

5 - Design and Simulation a New Dual Band Dipole Antenna for RFID Tags
Zahra Aref Darabi Sakineh Shirazi Tehrani

Radioidentificationsystemto identifyobjectswithout the use ofphysicaltoolsprovided. Eachof the system is include of three section, tag, reader and host computer that tag’s antenna is necessary to identified by readers. In this paper, new design of a dipole antenna More

Radioidentificationsystemto identifyobjectswithout the use ofphysicaltoolsprovided. Eachof the system is include of three section, tag, reader and host computer that tag’s antenna is necessary to identified by readers. In this paper, new design of a dipole antenna with rectangular fractal shape radiator element with two frequency range including Ultra High Frequency (UHF) band and microwave band has been obtained that using measured return loss bandwidth, also it can be simulated impedance bandwidth. The simulations show radiation pattern of the antenna is cover the entire frequency range including UHF and microwave  band. Manuscript profile

Open Access Article

6 - Comparison between land surface temperature estimation in single and multi-channel method using LandSat images 8
Parvaneh Asgarzadeh Ali Darvishi Boloorani Hossain Ali Bahrami Saeid Hamzeh

Land surface temperature (LST) is a key parameter in environmental studies particularly for drought monitoring. Due to the ground limitations to measure the LST on a large scale, thermal remote sensing is a unique method for estimating LST. The aim of this article is co More

Land surface temperature (LST) is a key parameter in environmental studies particularly for drought monitoring. Due to the ground limitations to measure the LST on a large scale, thermal remote sensing is a unique method for estimating LST. The aim of this article is comparing between LST estimation in single and multi-channel method using Landsat 8 thermal and reflective bands. Necessary ground data from meteorological stations Farabi (Khuzestan) and Karaj (Alborz) were taken to coincide with the dates and times of Landsat 8 overpasses. In this article Land surface emissivity and atmospheric water vapor content are major inputs for single and multi-channel LST estimation. After correction, processing and calculation of interest, LST were estimated. For result evaluation, statistical indices such as Root-Mean-Square Error (RMSE), Mean Absolute Error (MAE) and coefficient of determination (R2) were used. Results show the high value of R2 in all LST estimation method in comparison with ground measurement. In single channel using band 10 highest accuracy with MAE about 1.04 and 0.98 degrees in Karaj and Farabi station was seen respectively. The lowest and highest value of RMSE is in the single channel method (band 10) and multi-channel method (band 10 and 11) respectively. Study area conditions in terms of temperature; land cover and water vapor content affect the results and appropriate thermal band selection. Take-in consideration, especially using multi-band LST estimation method is suggested. Manuscript profile

Open Access Article

7 - Evaluation of heat transfer performance of two-phase nanofluid flow in a parabolic solar collector with eccentric absorber and solid insulation
mojtaba jamiati Hossein Pourmohamadian

In this study, the flow field analysis and heat transfer of two-phase nanofluid flow in a parabolic solar collector with eccentric absorber and solid insulation have been investigated. The fluid used in this collector is nanofluid of water - Aluminium. The main aim of c More

In this study, the flow field analysis and heat transfer of two-phase nanofluid flow in a parabolic solar collector with eccentric absorber and solid insulation have been investigated. The fluid used in this collector is nanofluid of water - Aluminium. The main aim of current study is to investigate the effect of using eccentric absorber system and solid insulation on the energy efficiency of linear parabolic collectors. For this purpose, energy efficiency has been measured and presented for different states (including ambient temperature, fluid inlet temperature, nanofluid volume fraction, nanoparticle diameter and geometric characteristics). The study is in turbulent flow regime and in order to model it, the k epsilon turbulence model has been used. In order to solve the survival equations, the finite volume method and the SIMPLE C algorithm have been used. Different optimal models are introduced in terms of having the highest energy efficiency, and the best model is determined. Based on obtained results, the highest energy efficiency in different Reynolds is related to the novel collector and two-phase model(TPM). In the next positions, respectively, are the novel collector and single-phase model(SPM), the basic collector and two-phase model, and at the end, the basic collector and single-phase model. It was also found that as the Reynolds number increases, all modes have an uptrend. The maximum amount of energy efficiency was for the novel collector and the two-phase model at Reynolds 15000, Which is equal to 68%. Also, the maximum energy efficiency for eccentricity 20 mm at Reynolds 15000, which is equal to 74.9%. Manuscript profile

Open Access Article

8 - A review on radiation heat transfer in gases based on quantum mechanics and heat transfer
mehrdad mesgarpour Ali Heydari seyfollah saddodin

Radiation heat transfer is one of the most important way to heat transfer. Almost 95 percent of heat transfer in the universe is radiation. Radiation heat transfer has basically different with other type of heat transfer. The radiation heat transfer have some special fe More

Radiation heat transfer is one of the most important way to heat transfer. Almost 95 percent of heat transfer in the universe is radiation. Radiation heat transfer has basically different with other type of heat transfer. The radiation heat transfer have some special feature. No need material to transfer and exist in any temperature above zero kelvin. Quantum mechanics can be describe a new horizon to explain sub atomic phenomena. It can also answer an old question that unsolved for many years. For example the concept of black body or gas radiation. In this study shown that the quantum mechanics is fundamental of radiation. Manuscript profile

Open Access Article

9 - Effects of rotational flow on energy efficiency of a novel parabolic through solar collector equipped with elliptical ribbed absorber tube filled with non-Newtonian two-phase nanofluid
mojtaba jamiati

The main purpose of this study is to investigate the effect of using an elliptical absorber system with helical ribbed tube on the energy efficiency of linear parabolic collectors. For this purpose, energy efficiency has been measured and presented for different modes, More

The main purpose of this study is to investigate the effect of using an elliptical absorber system with helical ribbed tube on the energy efficiency of linear parabolic collectors. For this purpose, energy efficiency has been measured and presented for different modes, and finally different optimal models are introduced in terms of having the highest energy efficiency, and finally the best model is determined. Based on the obtained results, the highest energy efficiency in different Reynolds is related to the new collector and single-phase model. According to the results of this dissertation, the use of grooved pipe has an effect on increasing the efficiency of the collector. As the number of grooves increases from 1 to 3, the collector efficiency increases. It was also found that the collector efficiency increases with increasing step and slope amplitude. by increasing the groove angle from 10 ° to 50 °, the collector efficiency increases and the maximum value of η is obtained at ° ξ = 60. However, by increasing the groove angle from 50 ° to 60 °, the collector efficiency decreases. Manuscript profile

Open Access Article

10 - Thermal and hydraulic analysis of a novel p double fluid parabolic through solar collector equipped with corrugated tube and insulator roof
mojtaba jamiati

The present study investigates a double-fluid volumetric based parabolic trough solar receiver. The control volume approach is used to solve the system of classical single phase governing equations by using the finite volume method. The standard k–ε turbul More

The present study investigates a double-fluid volumetric based parabolic trough solar receiver. The control volume approach is used to solve the system of classical single phase governing equations by using the finite volume method. The standard k–ε turbulence model with enhanced wall function is selected. According to obtained results, the value of efficiency of Conventional-Parabolic-Through-Solar-Collectors (CPTSCs) and Novel-Parabolic-Through-Solar-Collectors (NPTSCs) reduces by increasing of inlet temperature of base fluid and therefore, there is an optimum inlet temperature for all configurations and it is equal to 40°C. Manuscript profile

Open Access Article

11 - Effect of nitrogen fertilizer levels on some agronomic and physiological traits of wheat cultivars (Triticum aestivum)
Ali Bozorgi Hossein Abad Farzad Mondani Mohsen Saeidi Hasan Heydari Alireza Bagheri

In order to evaluate radiation absorption and use efficiency for wheat cultivars under effect of nitrogen fertilizer levels, a split-plot experiment based on the randomized complete block design with three replications was conducted during 2015-2016. The treatments were More

In order to evaluate radiation absorption and use efficiency for wheat cultivars under effect of nitrogen fertilizer levels, a split-plot experiment based on the randomized complete block design with three replications was conducted during 2015-2016. The treatments were four nitrogen fertilizer levels (90, 180, 300, 360 kg.ha-1 of urea) as main-plot and four wheat cultivars (Parsi, Zare, Pishgam and Orum) as sub-plot. The evaluated traits were included leaf area index, radiation absorption, crop growth rate, relative growth ratio, leaf dry weight, stem dry weight, total dry weight, radiation use efficiency and grain yield. The results showed that Pishgam cultivar compared to other cultivars had the most satisfying in terms of evaluated characteristics under nitrogen fertilizer rate treatments. By increasing the rate of urea fertilizer from 90 to 360 kg.ha-1, maximum leaf area index, radiation absorption, crop growth rate, relative growth ratio, leaf dry weight, stem dry weight, total dry weight and grain yield were improved. The most (8950 kg.ha-1) and the lowest (1264 kg.ha-1) grain yield weight were observed for Pishgam cultivar in 360 kgurea. ha-1 treatment and for cultivar variety in 90 kgurea. ha-1 treatment, respectively. The results also showed that the highest and the lowest radiation use efficiency were related to Pishgam cultivar (1.59 g.MJ-1) in 360 kgurea.ha-1 treatment and Orum cultivar (0.67 g.MJ-1) in 90 kgurea.ha-1 treatment, respectively. It seems that rising of nitrogen fertilizer by improvement of photosynthesis and crop growth rate caused to pick up dry matter accumulation and finally increased wheat radiation use efficiency. Manuscript profile

Open Access Article

12 - Heat transfer simulation of a four layer of porous radiant air heater under the enthalpy change between gas enthalpy and radiant energy
Mohammad Mehdi Keshtkar

This work presents the heat transfer characteristics of a new type of porous radiant air heater that operates on the basis of effective energy conversion method between flowing gas enthalpy and thermal radiation. At each layer, the gas and solid phases are considered in More

This work presents the heat transfer characteristics of a new type of porous radiant air heater that operates on the basis of effective energy conversion method between flowing gas enthalpy and thermal radiation. At each layer, the gas and solid phases are considered in non-local thermal equilibrium and combustion in the porous radiant burner is modelled by considering a non-uniform heat generation zone. The homogeneous porous media, in addition to its convective heat exchange with the gas, may absorb, emit, and scatter thermal radiation. In order to determine the thermal characteristics of the proposed porous radiant air heater, a two-dimensional model is used to solve the governing equations for porous medium and gas flow and the discrete ordinates method is employed to obtain the distribution of radiative heat flux in the porous media. In order to validate the applied numerical method at the present analysis, the results are compared with some reported theoretical and experimental results by other investigators and good agreement is found. Manuscript profile

Open Access Article

13 - Application of different cases of Hargreaves-Samani and Jensen-Haise methods for estimating Alfalfa Reference crop evapotranspiration in Isfahan
Payam Najafi

Estimating rate of actual evapotranspiration is very important for designing of the irrigation systems, storage construction and water conveyance structures. Many methods have been developed for estimating reference crop evapotranspiration. Amount of these methods are n More

Estimating rate of actual evapotranspiration is very important for designing of the irrigation systems, storage construction and water conveyance structures. Many methods have been developed for estimating reference crop evapotranspiration. Amount of these methods are need different climatic parameters but providing all of the data those are necessary for ET0 is not always available and if have been provided, these data may be is not completely correct. Therefore some methods have developed to estimating ET0 with minimum data such as Hargreaves-Samani and Jensen-Haise methods. In this research, eight cases of these methods have been compared. These comparisons were made on the basis alfalfa lysimeter data from Kabotarabud, Isfahan. The results show that through of these cases, which were used Samani-Pessarakly equation for calculating Extraterrestrial Radiation, were estimating ET0 better than the others with 15 Percent Average Maximum Absolute Relative Error (MARE). In addition, these above mention cases were had higher correlation coefficient as compare to other cases, so with improved the main equations with linear regression, MARE were decreased until 9 Percent. Finally, as compared the two methods of calculating the Hargreaves&oelig;Samani coefficient, Kt, the results showed that there was no considerable different between Allen's equation and Samani-Pessarakly's equation. Manuscript profile

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