Showing 7 results for Dadashzadeh
Volume 11, Issue 4 (Number 4 - 2009)
Abstract
Many research studies have been performed on forced convection (active) solar dryers for fruit and vegetables. A short survey of these showed that applying the forced convection solar dryer not only significantly reduced the drying time but also resulted in many improvements in the quality of the dried products. Active indirect and mixed-mode thin layer solar drying experiments were conducted on Sultana grapes. A combination of a solar air heater and a cabinet dryer was designed, constructed and tested for this product in the Agricultural Engineering Department at Shiraz University, Iran. Three air flow rates (0.085, 0.126 and 0.171 m3 s-1) and two types of drying systems (indirect and mixed-mode) were adopted. The south wall of the drying chamber was covered by a sheet of glass for mixed-mode and the glass sheet was covered with a thick sheet of cloth for an indirect solar drying system. Seven well-known thin layer drying models were used separately to fit the mixed-mode and indirect type experimental data for Sultana grapes. For experimental indirect data, the Modified Page model (r= 0.998, χ2= 0.000241) and for experimental mixed-mode data, the Page model (r= 0.999, χ2= 0.000169) showed the best curve fitting results with highest r (correlation coefficient) and lowest χ2 (reduced chi-square) values. The constants in these models explain the effects of drying parameters, air velocity and temperature. To take account of these effects, the best correlation equations between the constants and drying parameters were also introduced using multiple regression analysis.
Volume 14, Issue 3 (5-2007)
Abstract
Family is the initial cell and corner stone of a society that forms the base of characterization of the child. Health of society depends on health of family. Family with positive outputs renders mental and sentimental problem, socialize proportional children with the values and manners approved by society and arrange sexual behaviors.
Present paper aims to identify important factors effecting family break-up and their impacts on family.
For this purpose, out of 150 divorce applicants (30% male70% female), 107 samples were selected randomly and were studied by interview techniques based on, questionnaires. In this research tow hypotheses "economic difficulties are the laying ground for the family break – up" and "Absence of intimate space and sexual satisfaction are the factors of family brake – up as well as one question “Is annoyance the basis for family problems? Were studied.
The results showed that 63.6% of the society confirmed the economic problems in divorce whereas 24.3 of men of families seeking divorce were unemployed.
Of course, the proportion of unemployed men is 2/6% in Iranian families.
And the rate of employment in divorce families is 36.8% among the employment of all married women in Iran (12%). The difference between the indices of sample group with that of statistical society was at the level of P= 5% were significant.
93% of women and men were annoyed from each other.
Ahmad Khaleghian, Behnam Dadashzadeh,
Volume 15, Issue 13 (Special Issue 2016)
Abstract
Saeed Khodaei, Akbar Allahverdizadeh, Behnam Dadashzadeh,
Volume 17, Issue 6 (8-2017)
Abstract
This paper presents a new method based on machine vision for mobile robots to detect and avoid obstacles in unknown environments. One of the challenges of mobile robots trajectory control in unknown environments is that their obstacle avoidance system to be designed robust to material and shape of the obstacle. In this research a mobile robot equipped with a camera is designed and fabricated. Also an algorithm is proposed and implemented on the robot in order to detect obstacles by image processing and to control the robot trajectory. Three color laser pointers are mounted on the robot with certain angles that emit beams to the ground at ahead of the robot. The received images from camera contain these colored points that their coordinates are determined by image processing. Then position of any possible obstacle is detected using the proposed algorithm and the robot is commanded to avoid obstacles by changing its path. These obstacles can be static or dynamic. Our experimental results show that the proposed method, with a high reliability, has the ability to detect and avoid obstacles with any shape and material whereas other similar methods had restrictions in this regard.
R. Jahangiri, A. Allahverdizadeh , B. Dadashzadeh, H. Azimzadegh,
Volume 20, Issue 2 (February 2020)
Abstract
In this research, nonlinear transverse vibrations of a fluid conveying microtube under parametric magnetic axial resonance condition is studied. For this purpose, nonlinear governing equations of transverse motion of beam-like microtube are derived using Reddy’s first-order shear deformation theory with considering the effect of fluid viscosity and fluid centripetal acceleration. In this model, nonlinear terms of Hetenyi foundation and nonlinear geometric terms of the Von-Karman theory under magnetic excitations in the presence of fluid flow beyond the flutter instability is considered. In the following, the effects of foundation parameters on the linear flutter specifications of fluid conveying magnetizable microtubes are studied. Then, the nonlinear system behavior for fluid flow velocities more than critical velocity corresponding to the coupling of the first and second vibration modes is studied using multiple scales method. Nonlinear response curves in velocities above critical velocity are obtained and effects of variations of various system parameters including flow velocity, amplitude, and frequency of the magnetic field, Hetenyi foundation stiffness constants, viscosity, and dimensions ratio on the nonlinear response of the system are investigated. Some results indicate that increasing the values of shear stiffness parameter of the Hetenyi foundation has an unstable effect so that with its increasing, the flutter instability occurs at lower frequencies.
Volume 22, Issue 4 (Fall 2019)
Abstract
Aims: Curcumin (CUR) is a hydrophobic polyphenol compound and possesses a wide range of biological applications including cancer therapy. However, its prominent application in cancer treatment is limited due to poor solubility and bioavailability. Cyclodextrins (CDs) as natural nanocapsules are comprised of glucose units. One of the characteristics of them is to create complex with hydrophobic guest molecules in nanopores. In the current study, in order to improve the solubility, bioavailability, and efficacy of CUR, β-cyclodextrin-curcumin (β-CD-CUR) inclusion complexes were prepared and its effect on cancer and normal cells was examined.
Materials & Methods: In this study, first, β-CD-CUR complexes were prepared using freeze-drying method and the formation of these complexes was characterized by fluorescence spectroscopy. The encapsulation efficiency of CUR in β-CD was calculated for each concentration. After investigating the release of CUR from β-CD at different temperatures, the therapeutic effects of β-CD-CUR inclusion complexes for cancer and normal cell lines were evaluated by MTT assay.
Findings: The CUR encapsulation efficiency in β-CD was 33.92±1.32%. Fluorescence spectroscopic studies confirmed the formation of stable inclusion complex. The results also showed that CUR release from β-CD was higher in thermal conditions of cancer cells (42°C) than in normal cells and ambient temperatures. The results of MTT assay depicted that encapsulated CUR in β-CD has a significant inhibitory effect on proliferation of cancer cells compared to free CUR.
Conclusion: The results provided acceptable evidence for cell proliferation inhibition of β-CD-CUR complexes on cancer cells. There were no adverse effects detected for normal cells.
Pezhman Namashiri, Akbar Allahverdizadeh, Behnam Dadashzadeh,
Volume 23, Issue 9 (September 2023)
Abstract
Heart diseases are one of the most important causes of death in the world, and their treatment is very important from a medical and financial perspective. One of the effective ways that can be very useful in the treatment of cardiovascular diseases is computational modeling which can help medical professionals to better understand the human heart and provide more effective therapeutic approaches. The mechanical characteristics of the myocardium of human heart, known as a nonlinear and anisotropic tissue, are the most important part of the heart because it plays a key role in myocardial response to loading and unloading during heart cycle. In this study, the orthotropic hyperelastic and isotropic viscoelastic properties of the human heart were modeled by taking into account the effect of active stress on myocardium and using an idealized left ventricular geometry. Simulation results showed that the viscoelastic property cause the myocardium deformation to be damped and reduces the amount of torsion that experienced by the tissue. Also, myocardium tissue in viscoelastic case showed the hysteresis phenomenon which is found in clinical observations of heart mechanics. The Model is entirely implemented in COMSOL Multiphysics finite element software and can be used in heart electromechanical models in future studies.
