Foams built up by non-Newtonian polymeric solutions: Free drainage

A mathematical model of free drainage of foam built up by a power-law non-Newtonian liquid is developed. The theory predictions are compared with the experimental data on the drainage of foams formed using commercially available Aculyn™22 and Aculyn™33 polymeric solutions. The rheological parameters of the polymeric solutions were independently measured and used in the calculations. The deduced dimensionless equations were solved using finite element method with appropriate boundary conditions. The numerical simulations show that the decrease in the foam height and liquid content is very fast in the very beginning of the drainage; however, it reaches a steady state at longer time. The predicted values of the time evolution of the foam height and liquid content are in good agreement with the measured experimental data

Intensification of heat exchanger performance utilizing nanofluids

Heat exchangers are widely utilized in different thermal systems for diverse industrial aspects. The selection of HEx depends on the thermal efficiency, operating load, size, flexibility in operation, compatibility with working fluids, better temperature and flow controls, and comparatively low capital and maintenance costs. Heat transfer intensification of heat exchangers can be fulfilled using passive, active, or combined approaches. Utilizing nanofluids as working fluids for heat exchangers have evolved recently. The performance of heat exchangers employed different nanofluids depends mainly on the characteristics and improvement of thermophysical properties. Regarding the unique behavior of different nanofluids, researchers have attended noteworthy progress. The current study reviews and summarizes the recent implementations carried out on utilizing nanofluids in different types of heat exchangers, including plate heat exchangers, double-pipe heat exchangers, shell and tube heat exchangers, and cross-flow heat exchangers. The results showed that nanofluids with enhanced thermal conductivity, although accompanied by a considerable decrease in the heat capacity and raising viscosity, has resulted in performance enhancement of different heat exchangers types. So, the performance evaluation criterion that combines the thermal enhancement and increases the pumping power for any type of heat exchangers is requisite to evaluate the overall performance properly. The challenges and opportunities for future work of heat transfer and fluid flow for different types of heat exchangers utilizing nanofluids are discussed and presented

Relation of cultural and social attributes in dwelling, responding to privacy in Iranian Traditional House.

House as a shelter, from the early days of humanity, has been a worthy place, each culture and race has grown up under this shelter. Dwelling has always been such a fusion of living habits, environmental condition and cultural boundaries. Home is never created until there is a combination of comfort, fulfillment and a sense of belonging to a dwelling space. Privacy like security and peace is one of the rolling factors that affect housing forms. Since the past, Iranian architecture has emphasized on the relation between building and user. Culture and religious beliefs have concerned the Iranian user to have a suitable dwelling. The main result of this paper is that within Iranian traditional architecture the cultural affect on architecture has caused the division of the house in order to create privacy. These divisions by getting help from combination of open and closed spaces, has been formed professionally. The construction of the house was expanded in more than one floor with limited openings and view to outside; this is because of the inward looking feature of the traditional houses of Iran. On the other hand separation of house in to two or in some cases tree domains, public, private and in-between spaces has been one of these attempts, That made this architecture in accordance with people‟s culture and long lasting

Psychological and spiritual effects of light and color from Iranian traditional houses on dwellers

Light and color are the elements that has been playing important role in traditional architecture of Iran. Application of shadow and light with each other has been from the works that gives the mystical sense to the space, especially in religious spaces such as mosques. In view of light, as a major space component, the overall composition, with adjacent servant spaces, find a particular form of organization, which is centralized and where hierarchies define the general pattern. The order of structure, in which light comes as a containing discovering geometry, commands subsidiary openings, which imposes a disciplined regularity of spaces whilst offering greater complex layers of perception. In Iranian architecture, the study of light and color, in accordance with volumes and structure, has always been considered as an essential part of the different stages of the building and its realization. Giving the sensation of unity, this remains at the center of some conceived world‟s spirituality. Unfortunately false imitations from western architecture have given beautiful features but senseless spaces to the contemporary architecture of Iran. the proper teaching and tutoring the Islamic architecture with its principles, especially with suitable light and color applied, not only can describe a suitable feature of architecture, but also defines it in a word that revives the identity of Iranian architecture

Study of Adsorption of H2 and CO2 on Distorted Structure of MOF-5 Framework; A Comprehensive DFT Study

To investigate the adsorption property of H2 and CO2 on the organic ligand of C-MOF-5 (H2BDC) and T-MOF-5 (ZnO-doped H2BDC (ZnO-H2BDC)), Density functional theory (DFT) method was performed. First, the adsorption of ZnO on H2BDC resulted in examining binding energies, the charge transfer, density of states, dipole moments and adsorption geometries were investigated. The binding properties have been calculated and investigated theoretically for ZnO-doped H2BDC in terms of binding energies, band structures, Mulliken charges, and density of states (DOSs). According to obtained results, the H2BDC was strongly doped with ZnO. H2 and CO2 adsorption capacities for ZnO-doped H2BDC are significantly enhanced while there are low adsorption capacities for H2BDC. According to results, at least in the organic ligand of the MOF-5, the highest and lowest adsorption of CO2 (or H2) is attributed to the T-MOF-5 and C-MOF-5 respectively. Our calculations reveal that ZnO-doped H2BDC system (T-MOF-5) has much higher adsorption energy and higher net charge transfer value than pristine H2BDC (C-MOF-5). Also by changing in structure from cubic to tetragonal, the main site for H2 and CO2 adsorption was changed

Evaluating algorithms of decision tree, support vector machine and regression for anode side catalyst data in proton exchange membrane water electrolysis

Abstract Nowadays, due to the various type of problems stemmed from using chemical compounds and fossil fuels which have widely influence on whole environment including acid rain, polar ice melting and etc., number of researches have been leading on replacing the nonrenewable energy sources with renewable ones in order to produce clean fuels. Among these, hydrogen emerges as a quintessential clean fuel, garnering substantial attention for its potential to be synthesized from the electric power generated by renewable sources like nuclear and solar energies. This is achieved through the employment of a proton exchange membrane water electrolysis (PEMWE) system, widely recognized as one of the most proficient and economically viable technologies for effecting the separation of H2O into H+ and OH−. In this study, the important affecting parameters on the anode side of catalyst in PEMWE and analyzed them by machine-learning (ML) algorithms through developing a data science (DS) procedure were discussed. Various machine learning models were subjected to comparison, wherein the Decision Tree models, specifically those configured with maximum depths of 3 and 4, emerged as the optimal choices, attaining a perfect 100% accuracy across both Dataset 1 and Dataset 2. Moreover, notable enhancements in accuracy values were observed for the Support Vector Machine (SVM) model, registering increments from 0.79 to 0.82 for Dataset 1 and 2, respectively. In stark contrast, the remaining models experienced a decrement in their accuracy scores. This phenomenon underscores the pivotal role played by the data generation process in rendering the models more faithful to real-world scenarios

Управление сферой общего образования на муниципальном уровне (на примере города Тюмени)

Исследование управления сферой общего образования на муниципальном уровне (на примере города Тюмени)