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Showing 36 results for Ghadiri


Volume 1, Issue 1 (Winter 2021)
Abstract

In his classic paper on the philosophy of religion entitled ‘The Presumption of Atheism’, Antony Flew, relying on a traditional legal rule, extracts a methodological rule according to which the burden of proof in the problem of God’s existence is non-restrictedly on the Theist. Here we argue that from another legal rule in Islamic jurisprudence, we can extract another methodological rule that, in contrast to Flew’s rule, is context-dependent; so, applying this new rule, we can imagine that in some situations, the burden of proof would be on atheist. Since there are some historical evidence for the relationship or even identification of that traditional rule and this Islamic rule, it could be concluded that Flew’s rules, too, should be context-dependence. Hence, his non-restricted claim about the burden of proof in the problem of God’s existence will be rejected.


Volume 2, Issue 4 (Number 4 - 2000)
Abstract

Laboratory experiments were performed to determine the effect of various scarification treatments at four temperature regimes on germination of licorice seeds . A randomized complete block design with four replications was used. Germination counts were made every day for 2 weeks. At 50C, none of the chemically and mechanically scarified and non scarified seeds germinated. At 15, 25, and 350C, mechanical scarification increased seed germination to 94-98%. However, at these temperatures, velocity of germination of mechanically scarified seeds were lowest among all treatments. Chemical scarification also increased germination percentage significantly to 90-95% with 45 min soaking. At 15 and 250C, seed germination percentage and velocity of germination increased as the soaking time in sulfuric acid increased from 5 to 30, 45, or 60 min. However, at 350C, there was no difference in germination percentage between soaking times of 5 and 60 min. It appears that soaking for 45 min provides full germination at 25 and 350C.

Volume 3, Issue 3 (Summer 2023)
Abstract

Anthony Kenny develops a theory on religious language as follows: Firstly, a metaphor consists of using a word in a language game that is not its home; secondly, a word belongs to a language game if either the input to the game or its output involves contact with the word's object; thirdly, God does not belong to any language game. Thus, all uses of the ‘God’ are irreducibly metaphorical. Michael Scott proposes three objections to this theory: 1) Kenny’s criterion for words belonging to a language game is implausible. 2) it could be satisfied. 3) In some sentences, both the subject and predicate are religious expressions, so, the use of ‘God’ in these sentences is not metaphorical. Relying on Kenny’s account of the ineffability of God, in this paper, I shall introduce the ‘longitudinal otherness’ and argue on behalf of Kenny against Scott’s objections. However, I shall show that Kenny’s idea is objectionable.

Volume 5, Issue 3 (Fall 2021)
Abstract

Research subject: The use of hydroxyapatite nanoparticles (HAp) in traditional polymers as reinforcing agent has been reported. While there are a limited number of reports regarding the effect of HAp morphology on the mechanical properties of the polymeric matrix, no research on this effect on supermolecular polymers has been reported so far. This study investigates the hypothesis that incorporation of unidirectionally grown HAp nanoparticles (rod-like nanoparticles, rHAp) into supramolecular polycaprolactone (SPCL) leads to the synthesis of a new bioactive construct.
Research approach: For this, rHAp nanoparticles were first synthesized by microemulsion method and then functionalized with 2-ureido-4[1H]-pyrimidinone (UPy) groups. Moreover, PCL was functionalized and converted to supramolecular structures by reacting the hydroxyl terminal groups with UPy groups. Finally, SPCL/rHAp nanocomposites were synthesized by solution casting method and their structure and properties were examined using attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy, scanning electron microscopy (SEM), universal testing machine and simulated body fluid (SBF).
Main results: According to the results, microemulsion is an efficient procedure for the synthesis of rod-like nanoparticles with high phase purity. On the other hand, based on the results, it is possible to functionalize these nanoparticles with UPy. Tensile test showed that by incorporation of these modified nanoparticles into SPCL, a significant increase in both elastic modulus and tensile strength can be observed. In fact, while the initial PCL was a waxy solid, modification with UPy and then incorporation of modified nanoparticles made it an elastic material. Finally, the obtained results indicated high bioactivity of supramolecular nanocomposites compared to the sample without filler. Therefore, supramolecular SPCL/rHAp nanocomposites with bioactive properties and dynamic character can be used as a suitable replacement for bone tissue defects.

Behzad Ghadiri, Mani. Razi, Sabah Hamidi,
Volume 9, Issue 1 (12-2009)
Abstract

In this paper linear aeroelastic analysis of a swept wing with two degrees of freedom in an incompressible flow is investigated in time - domain. The equations of the motion of an elastic wing are derived from Lagrange’s equations in time - domain. The wing is modeled as a cantilever beam rigidly connected to the root. Considering assumed modes of cantilever beam, aerodynamic forces and moments acting on the wing are derived using strip - theory in an unsteady incompressible potential fluid flow. The governing aeroelastic equations of the system have been introduced in dimensionless form. These equations are solved via a numerical method. Comparisons between obtained results and both available experimental data and the results of some cited references indicate a close agreement.

Volume 10, Issue 1 (Number 1 - 2008)
Abstract

Hairsine and Rose (1991) developed a process-based soil erosion model which described the erosion transport of multiparticle sizes in sediment for rain-impacted flow in the absence of entrainment in overland flow. In order to test this model laboratory experiments were carried out in a detachment tray using simulated rainfall. Three contrasting soil types were subjected to simulated rainfall at different rates (25-110 mm h-1) in a 3530 10 cm detachment tray. Rainfall was applied using a rainfall simulator with a single scanning nozzle located four meters above the soil surface that emitted drops with a mean diameter (volumetric D50) of 1.5 mm. Results showed that the Hairsine and Rose model can clearly describe the sensitivity of different soils to erosion by introducing three terms of detachability, re-detachability and settling velocity, though the model is unable to describe aggregate breakdown which takes place in one of the soil at higher rainfall rates. The experimentally observed relationship between ponding water depth and soil detachability parameters did not agree with previously proposed theories. In addition, the results showed that the Hairsine and Rose model tends to over-predict values at the lower end of the scale, and under-predict values at the upper end, although the average sediment concentration predicted for the entire data set is not greatly different from the average measured values.

Volume 10, Issue 5 (Supplementary Issue - 2008)
Abstract

A knowledge of soil surface conditions, especially desert crust, salt crust and desert varnish is useful for improving classification of remotely sensed data. Desert crust can generate high levels of reflectance, similar to those areas with high salt concentration and non-saline soil. Therefore, soil surface crusts might bias thematic remote sensing of soils. In this study, we evaluated the efficiency of the Thematic Mapper (TM) and Enhanced Thematic Mapper plus (ETM+) reflective and thermal bands in detecting crusted surfaces and soil salinity conditions. The study areas were Ardakan, Damghan, Lut Desert, Qom, and Abarkooh which are located in arid regions of Iran. To assess the Landsat TM ther-mal data for detecting land cover types, the following steps were taken: 1) determination of correlation coefficients between TM wavebands, 2) assessment of the relationship be-tween TM thermal and TM reflective bands on land cover types, 3) assessment of the rela-tionship between soil salinity and TM Digital Numbers (DN), 4) two dimensional Feature Space (FS) analysis of the training samples, 5) field sampling, 6) image classification and accuracy assessment, and 7) comparison of surface reflectance of different soil surface types. The results show that the trend of correlation coefficients of TM6 with reflective bands is completely different from the correlation between reflective bands. The behav-iour of the thermal band on gypsiferous soils is completely different from that on saline soils. Moreover, with an increasing correlation between soil salinity and reflective bands, the correlation between soil salinity and the thermal band decreases. In image classifica-tion, the thermal band improved the separability of the crusted and gravely classes. Therefore the TM/ETM+ regions of the electro-magnetic spectrum have complementary capabilities for spectral separability of gravely and crusted surfaces. In general, selection of the TM/ETM+ thermal band combination is an important step for classifying the re-mote sensing data and for securing class separability of gravely and crusted surfaces in arid regions. We also concluded that TM/ETM+ thermal bands may contain information complementary to the TM/ETM+ reflective bands and therefore this combination of the TM/ETM+ thermal and reflective bands provide a viable method for soil salinity studies in arid regions.

Volume 12, Issue 1 (12-2020)
Abstract

The eukaryotic genome contains several replication Origins. Studies showed that the phenomenon and order of the origin activation is in a a particular discipline, called the “Replication Timing". Recent studies show that many factors are involved in regulating the timing of the replication process. One of the most important factors amongst them is the Rap1 interacting Factor 1 (Rif1) protein, which plays a key role in regulating the replication schedule in yeast and more advanced eukaryotes. Structure of this protein is mostly irregular and these properties prevent Rif1 from being expressed in a stable manner and makes it difficult to study.
The aim of the present study was to investigate the expression of recombinant C-terminal domain of mouse-Rif1(muRif1-CTD) protein in solution. For this purpose, the muRif1-CTD gene was extracted from eukaryotic constructs containing the complete Rif1 gene by PCR and was inserted into the pPAL7 expression vector comprising the Profinity eXact tag. Protein solubilization was carried out using different detergents and then detergent removal was performed by dialysis. In order to ensure that the soluble protein is active, the interaction analysis of the Rif1 protein with the G4 structures (previously reported to bind Rif1) was investigated using the gel shift assay. The results of this study showed the use of detergent for Rif1 solubilization without affecting its purification steps. But in the case of this protein, if the detergent is removed completely, it will not remain soluble.
 
 
 
 

Volume 13, Issue 1 (Number 1 - 2011)
Abstract

A two year field experiment was carried out to evaluate the competitive effects of wild mustard densities growing with rapeseed (cultivar Talaye) under different nitrogen rates. Treatments were wild mustard densities (0, 10, 20, 30, and 40 plant m-2) and nitrogen (N) rates (0, 50, 100, 150, and 200 kg N ha-1). The factorial set of treatments was arranged into a randomized complete block design with four replications. Rapeseed yield and the yield components decreased as wild mustard density increased. At 0 and 10 wild mustard plants m-2, grain yield increased with increasing N fertilizer up to 150 kg ha-1. At higher wild mustard densities, grain yield decreased above 100 kg N ha-1. These results indicate that increases in nitrogen application only increased the competitiveness of the weed versus the crop.
Ali Tayebi, Behzad Ghadiri, Mehrdad Manzari,
Volume 13, Issue 7 (10-2013)
Abstract

Smoothed particle hydrodynamics (SPH) is a fully Lagrangian particle method which solves a problem without using any mesh or grid. Pressure fluctuation is one of the main drawbacks of the weakly compressible SPH (WCSPH) method that leads to an inaccurate pressure distribution. In the present work, a diffusive term is added to the continuity equation to suppress the density and consequently pressure fluctuations. In contrast to the mesh-based methods, flow separation and inflow/outflow boundary conditions are two challenging issues in the SPH method. To overcome these problems, a new algorithm for inflow/outflow boundary condition as well as a particle shifting method is utilized for simulation of flow past a cylinder. Comparing the results with those of literature, it is shown that the method is capable to decrease the pressure fluctuations and solve problems including open boundaries as well as flow separation.
Mehrdad Yari Sakene, Behzad Ghadiri, Saleh Fallah, Farzad Safari,
Volume 13, Issue 13 (First Special Issue 2014)
Abstract

The aim of this research is to study effective parameters of incompressible, viscous and unsteady flow in Turbomachinary cascades using the Spalart-Allmaras (SA) RANS-Based Delayed Detached Eddy Simulation method. Detached Eddy Simulation is a hybrid RANS-LES method that was purposed in order to reduce LES computational cost. In this method, near wall, in boundary layer, RANS turbulence model is used and away from the wall, method automatically switches to LES. To develop original DES method (DES97), DDES was purposed to solve modeled stress depletion problem. A new function is introduced to the DDES model to make the transition from RANS to LES grid cell size independent. The numerical method that is used for discretization is staggered finite-volume and the grid is Cartesian. Also hybrid differencing scheme (the scheme compound of central differencing scheme and upwind scheme) to discretization of convection terms in Navier-Stokes is used. The results of this study compared with the results of simulation with SA turbulence model.

Volume 14, Issue 1 (1-2012)
Abstract

A field study was conducted to determine the integration of split N fertilization and herbicide application on weed management and wheat (Triticum aestivum L.) yield in Shiraz, Iran, in 2005/2006 and 2006/2007 growing seasons. The experimental design was split plot with four replications. Main factors consisted of N timing and splitting, and sub plots included iodosulfuron–methyl–sodium plus mesosulfuron–methyl–sodium, solfosulfuron and two weedy and weed free controls. Compared with the weedy check, iodosulfuron–methyl–sodium plus mesosulfuron–methyl–sodium and solfosulfuron reduced weed biomass by 66% in 2005/06 and 55% in 2006/07, 37% in 2005/06 and 45% in 2006/07, respectively. In all herbicide treatments applied in both years, the highest (353.6 kg h-1 in 2005/06 and 224.1 kg h-1 in 2006/07) and the lowest (65.6 kg h-1 in 2005/06, and 24.0 kg h-1 in 2006/07) weed biomass were obtained from the full N (304 kg urea ha-1) application at tillering stage and zero N application at sowing and stem elongation stages T1N0, T2N1, T3N0 and no N fertilization at sowing, tillering and stem elongation stages T1N0, T2N0 and T3N0. Nitrogen use efficiency of the crop increased when N was split. Consequently, wheat LAI and grain yield increased. However, in the presence of weeds, both LAI and grain yield increases were lower. The results of the present study showed that integration of N and herbicide treatments caused even a higher increase in wheat LAI and grain yield, but resulted in a higher reduction in weed biomass when compared with either treatment alone. N splitting of T1N½, T2N½ and T3N0 increased wheat grain yield (61% in 2005/06 and 75% in 2006/07), biological yield (76% in 2005/06, 94% in 2006/07), and LAI (62% in 2005/06 and 2006/07). In conclusion, weed control was essential for efficient use of N fertilizer by the crop. Therefore, in order to increase wheat grain yield, integration of split N and herbicide is recommended for the region. The results of this study showed that N splitting treatments of T1N½, T2N½, T3N0 and iodosulfuron–methyl–sodium plus mesosulfuron–methyl–sodium had the best efficiency in terms of weed control in wheat.
Sayed Mostafa Hosseinalipour, Mohammadmehdi Namazi, Arvin Behravan, Khashayar Ghadiri, Masoud Madadelahi,
Volume 14, Issue 9 (12-2014)
Abstract

In the present study, fabrication and performance testing of a flameless catalytic pad has been investigated. The catalyst was prepared with 1g of H2PtCl6.6H2O solved in 0.5 liter solvent contains 50% water and 50% ethanol and sprayed on the alumina - silica fiber mat as the catalyst support. The wet pad was dried and calcined before usage. The performance of the heater was evaluated by design and fabrication of a test stand which was capable of measuring parameters such as temperature at surface and in depth of the catalyst layer, the amount of pollutants such as CO and NOx, flow rate and pressure of the fuel and surface air circulation in front of the pad. In addition, by placing the panel containing the pad in an environmental test chamber, the effect of different climate conditions in five cities of Iran, i.e., Borojerd, Khalkhal, Lavan, Mahshahr and Puladshahr were investigated. Average surface temperature of the pad was measured about 350°C. No NOx was detected and CO emission of the burner was measured up to 5ppm. In Khalkhal conditions with the lowest temperature and humidity, the highest temperature at surface was recorded and the maximum CO emissions in Mahshahr with the highest temperature and humidity was about 3ppm. It was shown that increasing the fuel flow rate increases the surface temperature and CO emissions. It was also shown that an increase of environment temperature and humidity, increases the surface temperature.
Hamid Moosazadeh, Behzad Ghadiri Dehkordi, Masoud Rasekh,
Volume 14, Issue 15 (Third Special Issue 2015)
Abstract

A homogenous 2D plate with simply support boundary conditions is assumed. The effect of plate curvature and nonlinear deformation effects with cylindrical shell model and von Karman’s relation, has been introduced. Linear and Non-linear Frequency analysis with the effect of curvature and in-plane load has been investigated for the first time. Curved plate panel flutter, with the effect of supersonic aerodynamic and in-plane load has been studied for the first time. First and third order piston theory aerodynamic (PTA) is employed to model supersonic aerodynamic loading. Equations of motion have been derived by the use of Hamilton’s principle and resultant nonlinear PDEs have been transformed into nonlinear ODEs via Galerkin’s method. Forth and fifth order rang-kutta numerical method has been used to solve ODEs and define panel behavior. Results show that, structural linear frequencies increase with panel curvature, while, it is more complicated for non-linear frequencies due to the effects of in-plane loads. Fuethermore, 3rd order PTA theory has more critical effect on the instability boundary in comparison with 1st order PTA. The effect of in-plane load in aeroelastic phenomena make limite cycle osilation to chaotic motion for curve plates.
Behzad Ghadiri, Amid Khosrowdad, Mohammadreaza Asnsari, Hamed Houri Jafari,
Volume 14, Issue 15 (Third Special Issue 2015)
Abstract

Fluid-Elastic Instability is the most important mechanism among the vibration excitations in heat exchanger tube bundles subjected to cross flow. Flows through the heat exchanger are mostly two phase flow like air-water, vapor-water or Freon. Tow phase numerical methods are so complicated because of some parameters like VOF and interaction between two phases. Experimental studies are so problem and costly. Therefore, numerical methods are so important for studying two phase flow. In this Article, threshold of vibration has been numerically predicted by simulation of incompressible, viscose, and unsteady cross flow through a tube bundle in normal triangular arrangement. Interactions between the fluid and the structure has been counted in a fully coupled manner. HEM was used for analyzing two phase flow, In HEM method treats no difference in velocity between gas and fluid. In this study, two phase flow with HEM was solved around a single flexible cylinder surrounded by rigid and flexible tubes of bundle. Eventually, the flow through tube bundle has been simulated and analyzed by monitoring critical reduced velocity. Result shows that with increasing VoF, amplitude decreased and the critical velocity increased.
Mostafa Ghadiri, Mahmoud Mosavi, Mahdi Ghamami,
Volume 14, Issue 16 (Forth Special Issue 2015)
Abstract

Abstract Various methods have been proposed to produce metallic and bulk form materials.Severe plastic deformation, the ways in which you can set quite a lot of mechanical work applied to the metal. Various methods have been proposed to produce metallic and bulk form materials. However, despite the widespread need for tubes with high strength to weight ratio, few studies and attempts have been done to produce ultra-fine and nano structures.Ultra-fine grain metal created by the process have a high resistance by itself. therefore, these can be as high strength steels are used in harmony with the environment. In this study, optimal design of a cast is done in order to increase the homogeneity of the material microstructure and reduce applied force of the pipe production process.Finite element software is used to design the desired format. Since the framework has been designed based on the pressure in angular channels with parallel tube, the channels angles, corners and curved angles, reshaping and the channel radius ratio, the coefficient of friction between the pipe and the channel and the number of passes are the parameters affecting the process.The effect of the above parameters in a homogeneous effective strain rate and force of the process has been studied.
Saleh Fallah, Behzad Ghadiri, Ghasem Heidarinejad,
Volume 14, Issue 16 (Forth Special Issue 2015)
Abstract

Investigations of the phenomena associate with the Fluid-Structure interactionin transonic turbomachines due to the presence of unstable flow behaviors have double significance. Severe restrictions of the experimental methods, has developed researchers approach in this field to Numerical methods. Nevertheless, using simple two-dimensional model to investigate the phenomenon of quality is inevitable because of high computational cost of numerical methods in aerodynamic and aeroelastic simulation of full model of turbomachines. In this paper transonic flow in fixed fan cascade and fan cascade with central blade vibration in Forced harmonic pattern is simulated and variations of turbulence characteristic patterns are studied. In order to prevent divergence of the solution and achieve more accurate results, the step by step algorithm is developed. On the other hand, spring methodology with linear torsional springs is used for movement of dynamic grid around the oscillating blade. Mesh quality is assessed by examining maximum Mach number and y+ variation. Compare the results with the available experimental data indicated a significant difference in the position of the vortices are detached and re-attached. This difference proves need to use a turbulence model is more accurate in terms of the wide separation. In this paper, effect of blade geometry, flow separation and central blade oscillation on flow pattern and turbulence characteristics of transonic flow have been investigated. Obtained results explain the effect of mentioned parameters on the turbulence kinetic energy and dissipation frequency.

Volume 15, Issue 3 (5-2013)
Abstract

A two-year field experiment was carried out in semi-arid region of southern Iran (Shiraz), during 2007-2008 and 2009-2010 growing seasons using various mixtures of an early- (cv Falat) and a middle-ripening (cv Shiraz) winter wheat cultivar to evaluate the beneficial effects of inducing temporal growth heterogeneity on reduction of intra-specific competition during post-anthesis moisture stress conditions. Treatments were composed of five combination ratios of the two cultivars (1:0; 2:1; 1:1; 1:2, 0:1), and two levels of post-anthesis moisture conditions i.e. equal to Field Capacity and 50% FC. The results showed that the equal ratio (1:1 mixed cropping of early and middle-ripening cultivars) was superior in grain yield components as well as post-anthesis water use efficiency (PWUE) among the mixture treatments. It appeared that mixed cropping of early- and middle-ripening cultivars had the potential for altering the intensified competition under deficient moisture conditions and may improve PWUE. Additional research for determining the best choices of cultivars, mixing ratios, sowing date, phenological differences, input requirements, and management practices for each regional environment are essential to achieve the maximum benefits.
Hamid Moosazadeh, Behzad Ghadiri, Masoud Rasekh,
Volume 15, Issue 3 (5-2015)
Abstract

A homogenous 2D plate with simply support boundary conditions and local imperfection is assumed. The effect of nonlinear deformation with Reddy and marguerre plate model has been introduced. The effect of local imperfection in non-Linear vibration analysis with the effect of thermal and in-plane load has been investigated for the first time. The plate softening and hardening type with the effect of imperfection size is investigated. Flutter boundary of local imperfect plate with the effect of supersonic aerodynamic, thermal and mechanical load has been studied for the first time. First and third order piston theory aerodynamic (PTA) is employed to model supersonic aerodynamic loading. Equations of motion have been derived by the use of Hamilton’s principle and resultant nonlinear PDEs have been transformed into nonlinear ODEs via Galerkin’s method. Forth and fifth order rang-kutta numerical method has been used to solve ODEs and define panel behavior. Results show that, imperfection amplitude increase structural non-linear frequencie, and change plate softening type to hardening. Also, amplitude of plate vibration increase and flutter speed decrease continuously. Plate amplitude oscillation increase for small imperfection and decrease for larger imperfection versus flow speed.
Hamid Moosazadeh, Behzad Ghadiri, Puria Zarifian,
Volume 15, Issue 6 (8-2015)
Abstract

The application of wing and stabilizer in aerospace vehicle is most important to stability and flight motion. Nonlinear 2D wing is estimated. Nonlinear damping and stiffness with freeplay in plunging and pitching motion is assumed. 2nd order Damping nonlinearity and 3rd order stiffness nonlinearity in pitching and plunging motion is assumed. Fully nonlinear structure with nonlinear 3rd order piston theory aerodynamic is assumed for the first time and result evaluated with different references. The equations are defined with Hamilton principle with the use of kinetic and potential energy and virtual work. They are solved in the state space via the ruge-kuta numerical method to determine chaotic and limit cycle oscillation motion of supersonic airfoil. The result show that as the speed increases, the behavior of 2D wing is softening type with the use of nonlinear rotational stiffness. But, It shows hardening type with the use of transversal nonlinear stiffness. The effect of transversal and rotational freeplay is more complicated than other parameters and increases instability in low speed. In other hand the stability increases with freeplay in high speed. As shown, increase velocity decrease damping effect in post flutter behavior.

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