On the hydrodynamics and heat convection of an impinging external flow upon a cylinder with transpiration and embedded in a porous medium

This paper extends the existing studies of heat convection by an external flow impinging upon a flat porous insert to that on a circular cylinder inside a porous medium. The surface of the cylinder is subject to constant temperature and can include uniform or non-uniform transpiration. These cylindrical configurations are introduced in the analyses of stagnation point flows in porous media for the first time. The equations governing steady transport of momentum and thermal energy in porous media are reduced to simpler nonlinear differential equations and subsequently solved numerically. This reveals the dimensionless velocity and temperature fields of the stagnation-point flow, as well as the Nusselt number and shear stress on the surface of the cylinder. The results show that transpiration on the surface of the cylinder and Reynolds number of the external flow dominate the fluid dynamics and heat transfer problems. In particular, non-uniform transpiration is shown to significantly affect the thermal and hydrodynamic responses of the system in the circumferential direction. However, the permeability and porosity of the porous medium are found to have relatively smaller influences

Transient analysis of the interactions between a heat transferring, radial stagnation flow and a rotating cylinder-magnetohydrodynamic and non-uniform transpiration effects

This paper aims at providing further understanding on the fluid flow and heat transfer processes in unsteady rotating systems with mass transpiration. Such systems can be found in chemical separators, hydraulic systems, and printing devices. To this end, an unsteady viscous flow in the vicinity of an unaxisymmetric stagnation-point on a rotating cylinder is examined. The nonuniform transpiration and a transverse magnetic field are further considered. The angular speed of the cylinder and the thermal boundary conditions are expressed by time-dependent functions. A reduction of the Navier–Stokes and energy equations is obtained through using appropriate similarity transformations. The semisimilar solution of the Navier–Stokes equations and energy equation are developed numerically using an implicit finite difference scheme. Pertinent parameters including the Reynolds number and magnetic parameter and transpiration function are subsequently varied systematically. It is shown that the transpiration function can significantly affect the thermal and hydrodynamic behaviors of the system. In keeping with the findings in other areas of magnetohydrodynamics (MHD), the results show that the applied magnetic field has modest effects on the Nusselt number. However, it is demonstrated that the magnetic effects can significantly increase the imposed shear stress on the surface of the rotating cylinder

Multi-criteria decision making (MCDM) model for seismic vulnerability assessment (SVA) of urban residential buildings

© 2018 by the authors. Earthquakes are among the most catastrophic natural geo-hazards worldwide and endanger numerous lives annually. Therefore, it is vital to evaluate seismic vulnerability beforehand to decrease future fatalities. The aim of this research is to assess the seismic vulnerability of residential houses in an urban region on the basis of the Multi-Criteria Decision Making (MCDM) model, including the analytic hierarchy process (AHP) and geographical information system (GIS). Tabriz city located adjacent to the North Tabriz Fault (NTF) in North-West Iran was selected as a case study. The NTF is one of the major seismogenic faults in the north-western part of Iran. First, several parameters such as distance to fault, percent of slope, and geology layers were used to develop a geotechnical map. In addition, the structural construction materials, building materials, size of building blocks, quality of buildings and buildings-floors were used as key factors impacting on the building’s structural vulnerability in residential areas. Subsequently, the AHP technique was adopted to measure the priority ranking, criteria weight (layers), and alternatives (classes) of every criterion through pair-wise comparison at all levels. Lastly, the layers of geotechnical and spatial structures were superimposed to design the seismic vulnerability map of buildings in the residential area of Tabriz city. The results showed that South and Southeast areas of Tabriz city exhibit low to moderate vulnerability, while some regions of the north-eastern area are under severe vulnerability conditions. In conclusion, the suggested approach offers a practical and effective evaluation of Seismic Vulnerability Assessment (SVA) and provides valuable information that could assist urban planners during mitigation and preparatory phases of less examined areas in many other regions around the world

Source rock and shale oil potential of the Pabdeh Formation (Middle-Late Eocene) in the Dezful Embayment, southwest Iran

The Pabdeh Brown Shale Unit (BSU) is an organic-rich calcareous mudstone within the Paleogene Pabdeh Formation, which has not yet been investigated in detail. A total of 166 core and cutting samples were selected from four wells in the Dezful Embayment to investigate the organic geochemical and the mineralogical compositions, as well as the shale oil potential of the BSU. XRD results show that it is mainly comprised of calcite (53wt.%), clay minerals (25wt.%), and quartz (14wt.%). TOC contents generally range from 1 to 9wt.% (avg. 4.2, 2.9, 5.2 and 3.3wt.%, for GS, KR, RR and RS wells, respectively) with HI values ranging between 400 and 650 mg HC/g TOC. Based on average values of T max and vitrinite reflectance, as well as saturate biomarker ratios, the BSU is immature at wells RR and RS (ranging from 0.3 to 0.53%) and its maturity increases northward at wells KR and GS (ranging from 0.5% to 0.67%). The organic matter is dominated by Type ΙΙ kerogen and is generally composed of liptinite and amorphous material with minor terrestrial input. Based on various biomarker parameters, the organic matter was most likely deposited under anoxic marine conditions. The mineralogical characteristics (i.e. presence of brittle minerals) and organic geochemical properties (i.e. TOC >2wt% and Type II kerogen) support the conclusion that the Pabdeh BSU displays a considerable shale oil potential where it attains appropriate thermal maturity

The most useful medicinal herbs to treat diabetes

Diabetes mellitus is a syndrome that is characterized by hyperglycemia, change in the metabolism of lipids, carbohydrates, and proteins, and in the long term, with eye, kidney, cardiovascular, and neurological complications. Plenty of plants from different regions of the world have been investigated for anti-diabetic effects. This review article was designed to report some of the most important medicinal plants with hypoglycemic properties according to reliable clinical and laboratory evidence, and also touched on the medicinal plants that are prescribed in Iranian traditional medicine, for the treatment of diabetes. The information in this review was obtained from the eligible articles retrieved using the search terms diabetes mellitus, medicinal plants, type 1 diabetes and medicinal plants, type 2 diabetes and medicinal plants, and the effect of extract and essential oil of medicinal plants affecting diabetized tissues in the human body indexed in databases such as Iran medex, Irandoc, ISI, PubMed, Scopus, SID, Magiran, Google Scholar, etc. Based on the results drawn in this review the plants, Urtica, Trigonella foenum-graecum, Allium sativum, Carthamus tinctorius, Ferula assa-foetida, Bauhinia, Gymnema sylvestre, Swertia, Combretum, Sarcopoterium, Liriope, Caesalpinia bonduc, Coccinia grandis, Syzygium cumini, Mangifera indica, Momordica charantia, Ocimum tenuiflorum, Pterocarpus, Tinospora cordifoli, Salvia officinalis, Panax, Cinnamomum verum, Abelmoschus moschatus, Vachellia nilotica, Achyranthes, Fabaceae, Mentha, Asphodelaceae, Andrographis paniculata L, Artemisia herba-alba, Artemisia dracunculus, Azadirachta indica, Caesalpinioideae, Pachira aquatic, Gongronema latifolium, Nigella Sativa, Tinospora cordifolia (guduchi), Chrysanthemum morifolium, Zingiber zerumbet, Symphytum, Cactaceae, Symplocos, Perilla frutescens, Terminalia chebula and Aloe vera are effective to controland treat diabetes

The most useful medicinal herbs to treat diabetes

Diabetes mellitus is a syndrome that is characterized by hyperglycemia, change in the metabolism of lipids, carbohydrates, and proteins, and in the long term, with eye, kidney, cardiovascular, and neurological complications. Plenty of plants from different regions of the world have been investigated for anti-diabetic effects. This review article was designed to report some of the most important medicinal plants with hypoglycemic properties according to reliable clinical and laboratory evidence, and also touched on the medicinal plants that are prescribed in Iranian traditional medicine, for the treatment of diabetes. The information in this review was obtained from the eligible articles retrieved using the search terms diabetes mellitus, medicinal plants, type 1 diabetes and medicinal plants, type 2 diabetes and medicinal plants, and the effect of extract and essential oil of medicinal plants affecting diabetized tissues in the human body indexed in databases such as Iran medex, Irandoc, ISI, PubMed, Scopus, SID, Magiran, Google Scholar, etc. Based on the results drawn in this review the plants, Urtica, Trigonella foenum-graecum, Allium sativum, Carthamus tinctorius, Ferula assa-foetida, Bauhinia, Gymnema sylvestre, Swertia, Combretum, Sarcopoterium, Liriope, Caesalpinia bonduc, Coccinia grandis, Syzygium cumini, Mangifera indica, Momordica charantia, Ocimum tenuiflorum, Pterocarpus, Tinospora cordifoli, Salvia officinalis, Panax, Cinnamomum verum, Abelmoschus moschatus, Vachellia nilotica, Achyranthes, Fabaceae, Mentha, Asphodelaceae, Andrographis paniculata L, Artemisia herba-alba, Artemisia dracunculus, Azadirachta indica, Caesalpinioideae, Pachira aquatic, Gongronema latifolium, Nigella Sativa, Tinospora cordifolia (guduchi), Chrysanthemum morifolium, Zingiber zerumbet, Symphytum, Cactaceae, Symplocos, Perilla frutescens, Terminalia chebula and Aloe vera are effective to controland treat diabetes