Towards a Multi-Dimensional Approach in Inflow and Outflow of Compressible Flows

A novel multidimensional characteristics approach for inflow and outflow boundaries of compressible twodimensional flows is presented. The modified Riemann variables have been extracted from the Euler equations by considering the directions of waves reaching the inflow and outflow boundaries. By applying this model in a shortened computational domain, the boundaries can be located close to the nonlinear zone. The results of reduced and extended domains are in good agreement with each other. Using this model yields in a reduction of computational domain while keeping the solution accuracy and lowering the computation time

A lattice Boltzmann model for heat transfer in heterogeneous media

So far the lattice Boltzmann (LB) method has matured as a powerful tool to address a diversity of heat and mass transfer challenges. For most practical applications, the variation of thermophysical properties of working media will influence the performance of industrial systems substantially. However, nowadays the efforts to improve the LB method to consider variable thermophysical properties of working media are quite sparse. In the present work we firstly analyze the shortcomings of the available LB approaches for modeling working fluid with variable thermophysical properties. Based on the analysis, a simple LB model is proposed to overcome these shortcomings. The feasibility and reliability of the new LB model have been validated by three simple but nontrivial benchmark tests. Although it is originally proposed to simulate fluid flow with variable thermophysical properties, the present model can be extended directly to some other research areas where variation of thermophysical properties of working media should be considered, such as conjugate heat transfer between solid materials

Empirical Phenomenon, Subjective Construction And Ontological Trught: (An Analysis of Problems of Scientific Explanation and Critical Realism Approach)

Both the positivist and negativist frameworks of explanation are common in this naturalist proposition that unlike the metaphysical philosophy, reality is embedded only in experimental level. Therefore, the scientific explanation of natural and social phenomenon should refer to this experimental level in order to be called meaningful, verifiable and scientific. But, the problem was always that the principle of causality as a necessary condition for every kind of scientific explanation is not logically deductible from induction in experimental level and remains as a metaphysical principle. The principle of experimental objectivity as a condition for the verifiability clause of scientific explanations could not be defended, because the experimentation was always embedded in subjectivity and theory. The Kantian idealists, in contrast, considering the scientific explanation as a mere representation of reality in subjective categories, could not justify the experimental knowledge of reality and the rationality for comparison among theories and paradigms. Critical Realism as an important approach in philosophy of science that relates to the works and thoughts of Roy Bhaskar tries to solve these problems by resorting to its principles of ontological realism, epistemological relativism, and judgmental rationality. Considering and analyzing the scientific explanation’s issues, we have focused here on the answers of the Critical Realism in this case. We will argue that how the Critical Realist interpretation of scientific explanation, the experimental phenomenon, and the subjective construction and ontological reality all reach to a logical coherence with each other

Review of Phthalates Exposure and Toxicity

The dialkyl- or alkyl/aryl esters of 1, 2-benzenedicarboxylic acid, which are known as Phthalates, are high-production volume synthetic chemicals and considered as environmental pollutants, due to high production and uses in community, plastics industry and common consuming products. Di-(2-ethylhexyl) phthalate (DEHP) is the most abundant phthalate in the environment. Human exposure with DEHP could be done via different chemical compounds including food packaging, household furnishings, nutritional supplements, cleaning materials and insecticides. Besides, exposure of human with phthalates occurs through different pathways such as direct contact and using Phthalate-containing products, and indirectly through leaching into other products, or general environmental contaminations. Historically, the diet has been considered the major source of phthalate exposure in the general population, but in all sources, pathways, and their relative contributions to human exposures are not well understood. Medical devices are other source of significant exposure in human. Furthermore, cosmetics, personal care products, pharmaceuticals, nutritional supplements, herbal remedies and insecticides, may result in significant but poorly quantified human exposure with this compounds. In the present review article, we tried to discuss about metabolism of phthalates in human, toxicity, monitoring of phthalates in foods, environment, and cosmetic products and then metabolites of phthalates. Finally, evaluation of human exposure through biological control is discussed

Husseini Threnody in"Odes of Sharif Radi, Return-tie of Adibolmamalek Farahani and Hadikatu's-suada of Muhammad Fuzuli"

Abstract No doubt of Ashura event is the great epic and unmatched in human history. This is because of the poets of all different nations and peoples have explain that different aspects and have expressed them emotions in different formats. Among the poets in Arabic Literature is Sharif Radi who is Himself a descendant of Imam Hussein (AS). Among the poets of the Persian language can be named Adibolmamalek Farahani who with his brilliant Ashura Refrain mechanic has showed his art, and Among the poets in Turk poets is Fuzuli baghdadi who Is written Ashura poems and with Hadikatu's-suada and is the focus of most attention among the Turkic-speaking poets. This paper wish discussed common underlying Hosseini Lamentations of Odes of Sharif Radi, Return-tie of Adibolmamalek Farahani and Hadikatu's-suada of Muhammad Fuzuli with Analytic method. The poets According to their position in the cultures and separate courses each of them with different motives have expressed Imam innocence in the event of Ashura. Thus, despite different motivations for the burning of expression overlap in their contents is visible, Common themes, such as Attention of the three poets to issue of Karbala and Mention of Imam Hassan (AS) martyrdom in dealing with the event of Ashura, thirst, tears, and hurt the testimony of the Prophet (PBUH) because of event of Karbala is from these cases

THE EFFECT OF TRANSPORTATION INFRASTRUCTURE ONFOREIGN DIRECT INVESTMENT ATTRACTION IN IRAN

Weak transportation infrastructure in developing countries, e.g. Iran, presents abig obstacle to foreign direct investment attraction. One way of increasing theflow of foreign direct investment into a country is decreasing the production coststhrough expanding facilities as well as employing higher technology level. Thus,transportation cost usually is high in these countries and industries are oftenconcentrated in regions with more improved transportation system. The presentstudy aimed to investigate the effect of transportation infrastructure in Iran onforeign direct investment attraction. Hence, the researchers employed JohansenJuselius econometrics method to quantify the short run and long run effect oftransportation infrastructure, trade intensity, and market size on foreign directinvestment attraction during 1974-2007. The results emerging from the presentstudy indicated that transportationinfrastructure did not affect foreign directinvestment attraction in short run, but in long run, it had positive and significanteffect on foreign direct investment attraction

Using the porous medium to improve the forced convective heat transfer in the channel and its numerical analysis with lattice Boltzmann method

In this paper, numerical analysis of flow and heat transfer in a two-dimensional channel with porous medium and based on the lattice Boltzmann method is performed. The main reason for placing the porous medium inside the channel is to reduce the effective cross section of the channel and increase the localized mean velocity to increase the rate of heat transfer and control the maximum temperature of the hot plate. Also, due to passage of a part of the flow from inside of the porous medium, a sudden drop in pressure is prevented by reducing the cross-section. For this purpose, a porous medium with a random structure is considered in the upper part of the channel. The results include the effects of effective parameters such as Reynolds numbers, Prandtl number, aspect ratio and porosity of the porous medium on the maximum temperature, average Nusselt number and pressure drop. Results show that increase of the porosity increases the difference between the maximum temperature of simple channel and channel with porous medium. It is also observed that the use of a porous medium in the low Reynolds numbers creates a higher decrease in the hot plate temperature. In addition, increasing the Prandtl number initially increases the maximum temperature of the hot plate and its further increase will reduce the maximum temperature

Solid-liquid phase change investigation through a double pipe heat exchanger dealing with time-dependent boundary conditions

Highlights • Phase change of solid and liquid phases within a double pipe heat exchanger is modelled. • A porous medium with high thermal conductivity is used in PCM containers. • Sinusoidal function is chosen to oscillate bulk temperature and heat transfer coefficient. • Two PCMs of RT28HC and RT35 are considered for the heat exchanger. • Variation of liquid fraction values and PCM layers temperatures are reported. Abstract The use of phase change materials has been seriously recommended due to their high capacity of energy saving and delivering arising from phase change process. In addition, a constant temperature of melting or freezing provides a desirable condition to transfer a large amount of heat in a low-temperature fluctuation. This work attempts to present a numerical study to simulate the solid-liquid phase change considering a double pipe heat exchanger dealing with time-dependent boundary conditions. For this reason, a time dependent boundary condition of the third kind is applied. In a condition which the amplitude and periodicity of both bulk temperature and heat transfer coefficient (HTC) are varying in the sinusoidal form. The PCM container involves two separate sections to insert two different PCMs of RT28HC and RT35. In addition, in order to make up for the low thermal conductivity of PCMs, a porous medium with high thermal conductivity is located in PCM containers. Numerical model benefits the enthalpy-porosity approach based on the finite volume method, which models the phase change in the fixed grid domain. Moreover, in order to accurate simulation, fluid flow arising from Boussinesq approximation in the liquid phase is also considered using PISO algorithm. According to the results, the arrangement of RT35 in section A and RT28HC in section B accelerates the system response to the boundary oscillation. In addition, increasing the periodicity of the bulk temperature variation increases the amount of phase changing process in both sections while varying the same parameter of HTC does not influence the liquid fraction of PCMs considerably. Keywords Solid-liquid phase change; Time dependent boundary condition; Double pipe heat exchanger; Numerical study; Thermal conductivity enhancemen

The efficiency of collected biological samples from crime scene on crime detection

AIMS: The present study investigates the efficiency of biological samples taken from the crime scene on crime detection. METHODS. This study is a descriptive, documentary and applied. The statistical population of this research includes 60 employees of Zanjan State Criminal Police, including crime scene investigators, lab experts of forensic chemistry and biology, forensic detectives, medical examiners and examining magistrates and prosecuting attorneys of Zanjan province’s Judicature with at least 5 years of executive experience in crime scene investigation. The questionnaire is used as a tool in this study. The validity of the questionnaire was confirmed by the experts and the reliability of the questionnaire, calculated by the Cronbach's alpha coefficient, was 0.939. For analyzing, descriptive and inferential statistics Kolmogorov-Smirnov, Friedman and one sample t-tests were used. The Kolmogorov-Smirnov test showed normal distribution of the data; so the parametric tests were used to examine the variables. FINDINGS. The results of one sample t-test showed that biological samples of blood, saliva, semen, and hair strand make a significant contribution to the scientific detection of crime. Friedman test for ranking the importance of various factors related to different samples on crime detection rate from the view of the respondents, showed that using modern equipments and technologies, sample quality and officer scientific and technical knowledge have the most priorities. CONCLUSION. According to the results the best biologic test, from the view of the respondents, in crime detection is DNA typing