Showing 23 results for فدایی
Volume 9, Issue 1 (Spring 2019)
Abstract
The industrial architectural heritage is the result of the interaction of culture and industry that nowadays due to the unique identity and values of industrial heritage and with the industries outflow from urban areas have turned into unused areas requiring adaptive reuse. Besides, their similarity to other forms of architectural heritage, industrial buildings have unique components such as special scales, the great mass of materials and indelicacy of space, each of them brings some forces in recognition and designing the project and appearing as new limitations and opportunities for designers. Nowadays, the reuse through retooling interventions is not systematic and is regarded as one of the most important necessities for development and reconstruction in urban industrial areas. Therefore, drawing up and synthesis of various theories on the subject shall be done within a developed framework based on maintenance of the sense of place and the possibility of reviewing the authentic visual character of the building which requires reviewing and identification of valid theories and documents presented so far to create adaptation of new conditions and the authentic building in relation with its environment. Indeed, in addition to conservation, it leads to emergence of time and creativity in parallel with the achievement of sustainable conditions. Retooling the heritage buildings include certain components that should be analyzed in an integrated and comprehensive ways at three levels of architecture, infrastructure and structure before beginning of interventions and without undesirable effect on the authenticity of environment and architecture. All these items are the main pre-intervention necessities and in the present research it is tried to make logical and comprehensive relation to create new conditions for functional updating of the areas with industrial, although depreciated, identity. The present research is qualitative, which using the strategy of logical reasoning for the developing of conceptual framework leads to recognition of effective components in the retooling process of industrial architectural heritage; components that are simultaneously influenced by adaptive reuse strategy in historical buildings.
Volume 11, Issue 3 (9-2011)
Abstract
In this paper, free vibration analysis of moderately thick smart FG rectangular plate is presented on the basis of Mindlin plate theory. This structure is composed of a host FG plate and two bonded piezoelectric layers. The plate has two opposite edges simply supported (i.e., Levy-type rectangular plates). The closed circuit piezoelectric layers can be used as an actuator. According to a power-law distribution of the volume fraction of the constituents, material properties vary continuously through the thickness of host plate. Using Hamilton's principle and Maxwell electrostatic equation, six complex coupled equations are introduced. These equations are exactly solved introducing the new potential and auxiliary functions as well as using separation of variables method. The accuracy of the frequencies is verified by the available literature and the finite element method. The present exact solution can accurately predict not only the out of plane, but also the in-plane modes of FG plate. Finally, the effects of various parameters such as boundary conditions, gradient index and thickness of piezoelectric layers on the natural frequency are investigated.
Volume 11, Issue 3 (7-2004)
Abstract
This paper discusses the number of scholars and their scientific interests in the reign of Bu-veyhid. Buveyhid the most important Iranian-Shi ‘it dynasties appeared in the early era of Islam. They were so powerful that the Abbasid Caliphs had to obey them. According to their Shi ‘it religion, they practiced the idea of democracy and all sects were free in their reign. According to the survey more than 350 scholars were prominent in this period, during 320/900- 450/1050. If we count their specialty, the number increases to about 714. What is in-teresting is that we can find all fields specialists at that time. They are from all religions and also Islamic sects. The number of Shi ‘it scholars is outstanding among them.
Volume 11, Issue 4 (9-2011)
Abstract
in this paper natural frequencies of a rectangular mindlin plate with surface bounded piezoelectric patches is obtained. Simply supported boundary condition is imposed at the plate edges. Ritz approach based on the principle of minimum potential energy is applied to obtain the frequency parameters of rectangular plate. Since displacement fields of the plate are postulated by trigonometric series function, solution is a semi analytical one. For verifying the accuracy of this method, results are for the isothropic and piezoelectric plates are compared with those reported in the literature. As we see a good conformance is derived from the obtained results and the exact solution. At the end, natural frequencies of a rectangular mindlin with surface bounded piezoelectric patches is obtained.
Volume 12, Issue 3 (9-2023)
Abstract
This study was performed to determine the identification (barcoding) using cytochrome oxidase gene of common carp, between three provinces of Golestan, Mazandaran and Gilan (respectively in Gomishan, Tajan and Kiashahr) in 2011. The results of sequencing showed that all samples from the three regions had a genetic distance less than 2%, so all samples were from the same species. The results of sequencing 30 tail samples of carp species on the southern shores of the Caspian Sea showed that all samples are of the same species and their genetic distance does not reach at least 2%. Therefore, all carp samples of the three provinces are of the same species and have the same type of barcode. In the study of nucleotide and haplotypic distance, Gomishan region was 10.75000, 1 and Kiashahr region were 3.200 and 0.9333, respectively. In the study of nucleotide diversity between the two regions, 0.01978 and the average nucleotide difference was 12.187. Haplotypic diversity in Gomishan region was 38.095 and in Kiashahr region was 23.809%. Out of 13 haplotypes, Gomishan region with 8 haplotypes (61.53%) and Kiashahr region with 5 haplotypes (38.46%) had the lowest haplotypes.The results of this study show that there is a significant difference between carp samples in Gomishan and Kiashahr regions in terms of nucleotide and haplotypic diversity (P <0.05).
Volume 12, Issue 5 (1-2013)
Abstract
In this article, a special duct is introduced in which, inlet water jet initiates to oscillate after a short time and it causes the velocity and pressure to oscillate regularly. Considering that there is a linear relationship between the inlet jet velocity and its oscillations frequency, the flow rate can be calculated by measuring the pressure frequency. In order to study the flow field inside the current geometry of fluidic oscillator and also to find the optimum location for sensor to detect the pressure oscillation, the unsteady turbulent Navier-Stokes equations are solved by ANSYS CFX software. Having studied the grid independency, capability of K-ε and SST turbulence models for numerical simulation of unsteady flow inside the fluidic oscillator is considered. Then, according to the peak to average ratio (PAR) criterion, the qualities of pressure signals are compared at some points, to distinguish an optimum pressure sensor position. Afterwards, a prototype of fluidic oscillator flow meter is manufactured for the first time in Iran. Using this prototype and inserting the pressure and Piezoelectric sensor at the optimum point, the numerical simulation results are validated by the experimental data. Comparison between the numerical and experimental results shows that the SST model is more suitable for this flow simulation. Finally, by performing experiments in different flows, acquiring and processing pressure signals, the flow meter characteristic diagram (inlet jet oscillations frequency- inlet jet velocity) are extracted.
Volume 13, Issue 4 (1-2023)
Abstract
Aflatoxin B1 is a type of mycotoxin produced by Aspergillus fungi during food production and storage. Aflatoxins have many toxic effects on the body that cause mutagens, teratogens and have high carcinogenic properties that cause cancer in the liver and other organs. Although conventional device methods for measuring aflatoxin B1 in food are sensitive and accurate, they have disadvantages such as high diagnostic time, high cost, the need for a trained user, and the creation of false positive results. Therefore, the development of new measuring methods has been prioritized by researchers. Among these measurement methods is the use of biosensors, which are fast, simple and more affordable and are used in the food industry today. In this work, a colorimetric optical aptasensor using gold nanoparticles with appropriate sensitivity and high selectivity was used to detect aflatoxin B1 in serum and buffer. For this purpose, gold nanoparticles were synthesized by reducing HAuCl4 by sodium citrate (with a size of 14.40 nm and a zeta potential of -27.5). In this method, the protective effect of DNA sequence on the surface of gold nanoparticles has been used in the presence or absence of aflatoxin with the intervention of salt and the characteristic of visual color change. The detection limit of this method was estimated to be 50 ng/L and its linear range was 200-28000 ng/L. As a result, the designed aptasensor can be used for quick identification and screening of this toxin in contaminated food.
Volume 13, Issue 15 (Third Special Issue 2014)
Abstract
This paper presents a transient model for planar solid oxide fuel cells anode, which allows the simulation of steady-state performance characteristics, transient operation behavior, as well as electrochemical impedance spectra. The developed model couples the mass transport with electrochemical kinetics. The 1D Navier-Stokes conservation equations and species conservation equations are used for gas transport in the anode channel, and the linear kinetic is used for the anode electrochemistry. In order to model the electrochemical impedance, a sinusoidal excitation is imposed to system of transient equations and the obtained harmonic response is used as a base for electrochemical impedance spectra simulation. In order to solve the system of the nonlinear equations, a numerical code based on finite volume method is developed and utilized. Results show that the mass transfer in channel leads to a low frequency capacitive semicircle in the Nyquist plot. Moreover, the influence of parameters such as overvoltage, temperature, velocity and hydrogen inlet concentration on the electrochemical impedance has also been studied and the results are discussed. The simulation results are in good agreement with published data.
Volume 14, Issue 14 (Second Special Issue 2015)
Abstract
In this article, an analytical procedure is presented for prediction of linear buckling load of a waffle cylinder stiffened by an array of equilateral triangles. The grid stiffened shell is subjected to axial loading condition. The shell has simply supported boundary conditions at its two edges. The equivalent stiffness of the stiffener and skin is computed by superimposing between the stiffness contributions of the stiffeners and skin with a new method. Total stiffness matrix of the shell is composed of stiffness matrix of skin and grids with special volume fractions. In this analysis, using energy method, equilibrium equations of the grid stiffened shell are extracted based on the thin shell theory of Flugge. The Navier solution is applied to solve the problem. A 3-D finite element model was also built in ANSYS software to show the accuracy and validity of the present solution. The results show that the present new approach has high accuracy and precision. The effect of various geometrical parameters on the critical buckling load is investigated. Due to the stability and accuracy, the present method can be used by many designers and engineers to improve their design quality.
Volume 15, Issue 4 (2-2013)
Abstract
Objectives: Platelets are anucleated fragments derived from megakaryocytes. It has been demonstrated that platelets play a role in hemostasis and innate immunity. In addition, platelets have a CD40 ligand which is an important molecular marker in motivating immune cells. Thus, platelets also have a role in adaptive immunity as seen by their ability to activate B cells. Since human platelet microparticles (MPs) originate from platelets, we have chosen to examine the effects of MPs on B cell activation.
Methods: Platelet MPs were isolated from platelet concentrates obtained from theTehranBloodTransfusionCenter. The MPs were co-cultured with B cells isolated from human whole blood with magnetic beads using negative selection. After seven days, the expression of activation markers CD27 and CD86, as well as IgD were evaluated by flow cytometry.
Results: In a comparison between test (B cells/MPs) and control (B cells) cells we observed that the expression of activation markers CD27 and CD86 increased during the seven-day co-culture period. However, the expression of IgD antibody decreased.
Conclusions: As with platelets, MPs can affect B cell activation during in vitro co-culture.
Volume 16, Issue 6 (8-2016)
Abstract
In this paper, equations of motion for a horizontal axis wind turbine with movable base are extracted and natural frequencies and vibration of the system is studied. The wind turbine tower is assumed rigid while its blades are modeled as flexible beams. In-plane bending and twisting are considered as two degrees of freedom for blades motion.The shaft connected the tower to blades is assumed rigid and its rotational velocity is considered.In this paper, specifically, a 5-megawattfloating horizontal axis wind turbine, which it’s basehas three angular velocities in different directions,is studied.Due to the complex shape and variation of the properties along the length, the turbine blade properties such as mass and geometric parameters are extracted by curve fitting in MATLAB.The equations of motion and boundary conditions are derived by Hamilton's principle and then are transformed to ordinary differential equations by Galerkin method. By setting the governing equations to standard form (space state), eigenvalues and frequencies are calculated. The numerical results are compared with published results and good agreement is observed.Then the effect of various parameters on turbine blades frequencies and time responses are demonstrated. Results show that the tower base angular velocity and blades rotational speed have considerable effects on turbine blades time response and vibration frequencies.
Volume 16, Issue 89 (7-2019)
Abstract
Ice cream yogurt is one of the dairy frozen products, which is in terms of physical characteristics and the appearance of ice cream. Due to the presence of lactic acid bacteria and the fermentation process, it has a high nutritional value; also it has a lower amount of sugar and fat than ice cream. In the present study, the effect of adding White mulberry juice and Teranjabine (at 0, 20, 40, 60, 80 and 100% levels) on some physicochemical properties (percentage of Over-run, pH, acidity, melting resistance, apparent viscosity and total sugar content) and the sensory evaluation of ice cream yogurt were evaluated. The statistical method was factorial experiment in a completely randomized design with three replications. According to this study, With Increasing the percentage of white mulberry juice and Teranjabine in ice cream yogurt samples: acidity and viscosity increased (p <0.05), Over-run and melting resistance decreased and increased respectively (p <0.05), and pH and total sugar content increased and decreased respectively (p <0.05). According to the results of the sensory evaluation, the best sample from the taste, color, texture, sweetness and overall acceptance of the sample with the replacement level of 40% white mulberry juice and 60% Teranjabine were taken. Totally, the sample of containing 40% White mulberry juice and 60% Teranjabine was selected as the best sample, which can be produced as a dietary product in dairy industry.
Volume 17, Issue 10 (1-2018)
Abstract
Shape memory alloys are a category of smart materials which exhibit large deformations under temperature or magnetic stimuli due to micromechanical changes. These alloys offer a good potential in design of control systems, sensors and actuators due to two main effects called shape memory effect and superelastic effect. Main advantages of these systems are their small scale, low weight, low activation power, long life and high power to weight ratio. On the other hand, the main disadvantage of thermal ones is their low actuation frequency. In this work, inspired by human arm muscles, a new actuator is designed and its actuation time is minimized utilizing the thermoelectric effect. The process requires simultaneous analysis of heat transfer, constitutive equations, phase transformation and also the dynamic equations of the actuator. The dynamic response of the designed actuator is compared with the similar experimental data available in the literature and finally it is shown that, the actuation time of the proposed actuator can be reduced at least 50% thanks to the Peltier effect.
Volume 17, Issue 100 (june 2020)
Abstract
Drying is one of the ways of storing of persimmon. In this study, to increasing shelf life of persimmon and producing high-quality products, infrared dryer was used and mass transfer kinetics, density, rehydration and color of samples were measured. The results showed that radiation lamp power and distance of lamp from sample had significant effect on the moisture loss kinetics and drying time (P<0.05). With increasing in radiation power, as well as reducing the distance of samples from the source of radiation, drying time decreased. The average density and rehydration for the dried samples in infrared were 639 kg /m3 and 270 %, respectively. The average calculated color changes (ΔE) for the power of 200, 300 and 400 w were 14.43, 10.09 and 20.04, respectively. The results of modeling by genetic algorithm-artificial neural network showed that artificial neural network combined with genetic algorithm provides better results and with combine them the speed of analysis and accuracy of modeling process increases. Using a network with 15 neurons in the hidden layer and using the hyperbolic tangent activation function and percentage data used to training/validation/testing equal 20/20/60 may be predicted drying kinetics of persimmon.
Volume 18, Issue 121 (March 2022)
Abstract
One of the reasons of the bakery products poor quality and quality defection in the country is the low quality and the impropriety of wheat. Regarding the uncontrollability of so many effective factors in wheat quality. Using of improving agents in wheat flour has been highly considered. In this study, the effect of tow improving agents, ascorbic acid in three levels (20, 40, 60 ppm) and α-amylase enzyme in three levels (25, 50 and 75 ppm) over dough was investigated. Rheological tests results showed that increasing level of ascorbic acid from 20 ppm to 60 ppm is effective in dough stability time and dough developing time increment, reduction in dough softening degree, increasing elasticity, improving gluten structure and increasing the usage level of α-amylase enzyme from 25 ppm to 75 ppm is effective in the collapse of polymeric structure of starch, dough softening, stability, developing time and reduction elasticity characteristics. In simultaneous use of additives in constant amount of α-amylase enzyme, increase of ascorbic acid from 20ppm to 60ppm causes rheological individually betterness. Dough stability time, developing time and dough elasticity as well. This effect in constant amount of ascorbic acid shows a diverse relationship specially with high amount of added α-amylase (50 and 75 ppm). Generally, in addition to ascorbic acid containing treatment on its own using of α-amylase enzyme in 50 ppm level with 60 ppm ascorbic acid in improving the rheological and quality specialty of dough is suggested.
Volume 19, Issue 3 (March 2019)
Abstract
In this article, an exact analytical approach is presented to analyze free vibration of a thin piezoelectric spherical shell, using thin shallow shell theory. The piezoelectric spherical shell is modeled as a sensor or an actuator. The piezoelectric material is polarized through the thickness of the shell. Using the separation of variables method as well as some new potential functions, the equations of motion and Maxwell’s equation are exactly solved, simultaneously. First, the equation of the transverse displacement of the shell is separately obtained and after extracting the transverse displacement, other unknowns such as the in-plane displacements and electrical potential function are obtained. Then, applying mechanical and electrical boundary conditions, the natural frequencies of the shell are obtained for the sensor and actuator cases. In order to validate the accuracy of the present method, the obtained results are compared to those obtained by a finite element analysis in ABAQUS software. Also, the effects of various parameters such as inner radius to radius of curvature of the shell ratio, thickness to inner radius ratio, and different boundary conditions on the natural frequencies are considered. Results show that piezoelectricity effect causes an increase in strain energy of the structure leading to increasing the natural frequencies for both sensor and actuator shells. Also, by changing the conditions from actuator state to sensor one, the structure experiences an increase in the natural frequencies.
Volume 19, Issue 124 (June 2022)
Abstract
Celiac disease is the most common disease caused by gluten consumption. Gluten protein, is the most important compound in creating tissue and contains components of the formulation of baking products. This protein causes allergies in people with celiac disease, and the only way to treat the disease is to eat a gluten-free diet for a lifetime.Therefore, the use of appropriate alternatives to gluten in the preparation of this category of products is essential. Therefore, the aim of this study was to investigate the effect of rice bran protein concentrate in the amount of 0.75. , 1.5, 2.25, 3 % as a gluten substitute for sponge cake. Based on the results, it was found that the viscosity of the product dough has increased compared to the control sample and the addition of rice bran protein has a significant effect on the density of sponge cake dough. Also, increasing the protein concentrate in mentioned amounts caused a significant increase in the moisture and specific volume of the cake. The results of tissue stiffness analysis of the samples showed that there is a significant difference compared to the control sample. According to the results, the highest score was given to the sample containing 2.25 rice bran protein and the selected treatment was T3 treatment.
Volume 19, Issue 124 (June 2022)
Abstract
Rice bran can be a suitable compound for bread enrichment due to its considerable amounts of fiber and protein. However, the addition of rice bran due to impaired textural and sensory properties as well as the presence of phytic acid in it should be further investigated. On the other hand, when bread bakes at temperatures above 120 °C through millard reaction, a carcinogenic compound called acrylamide is produced which can be minimized by removing the effective factors in its production. In this study, ordinary rice bran and hydrothermaled rice bran were used in different percentages of 3, 6 and 9% to enrich wheat flour and molded bread. Then, color changes, acrylamide levels and textural properties were measured. The results showed that with increasing the use of bran in bread, the amount of discoloration and acrylamide concentration increased and the samples containing hydrothermal bran had higher acrylamide levels. Hardness, adhesiveness, gumminess and chewiness had an increasing trend with increasing bran percentage, while cohesiveness and springiness showed a decreasing trend with increasing bran percentage. According to the results obtained based on the ADI of acrylamide and due to the reduction of phytic acid in bread samples, treatment containing 3% hydrothermal bran not only had the lowest acrylamide content and at the same time had the lowest amount of phytic acid, but also had acceptable tissue and appearance characteristics.
Volume 19, Issue 132 ( February 2023)
Abstract
Adding the fiber sources in food formulation is one of the best methods for enriching and improving nutritional value of food. Cereal bran is one of the best and most economical sources of dietary fiber supply. In this study hydrothermaled wheat and rice bran in optimum condition and in different content (0, 4, 8%) were added to wheat flour. The result of Rheological experiment indicated that increasing in the content of wheat and rice hydrothermaled bran in dough leads into significant decrease of dough quality number and significant increase in water absorption. On the other hand, increasing the amount of rice and wheat bran was also associated with an increase in dough development time. Evaluation of texture and color changes also indicated a direct relationship between biscuit hardness, color and content of wheat and rice bran. Sensory evaluation performed by evaluators on biscuit samples also indicated a significant decrease, in case of increasing the amount of wheat and rice bran and replacing the hydrothermal rice bran in the formulation. According to the results, the use of 4% hydrothermaled wheat and rice bran is suitable for enrichment of nutritional value of biscuits and it is suggested.
Volume 21, Issue 156 (February 2025)
Abstract
Celiac disease is an autoimmune disorder which can cause serious damage to the mucous membrane of the small intestine due to the consumption of gluten, and as a result, there is a decrease in the absorption of nutrients, which can lead to weight loss, anemia and malnutrition. Removing gluten from the diet of the affected person is suggested as a solution to control and curb this abnormality. Therefore, the aim of this research is to investigate the possibility of producing cookies using rice flour, quinoa, carboxymethyl cellulose gum (1.5-3-5 percent) and gum extracted from the quince seed (1.5-3-5 percent) alone and evaluating its effect on the rheological characteristics of dough and textural properties of cookies. Based on the obtained results, it was determined that with the addition of gums, the viscosity increases compared to the control sample. Also by adding gums, Peak and Final viscosity increased and the setback viscosity decreased compared to the control sample. It was observed that the seed gum performed more effectively than showed carboxymethyl cellulose gum. So that the treatment with 5% quince gum has the highest viscosity among the samples. Furthermore the addition of both types of gum resulted in reduced hardness, increased springiness and improved sensory characteristics. Based on the overall evaluation of the results of the present study, sample number 7 containing 450 g rice flour, 50 g quinoa flour and 5% quince gum is recommended as the best treatment.
