Exact Solutions for Orthogonal and Non-Orthogonal Magnetohydrodynamic Stagnation-Point Flow

The viscous plane flow of an electrically conducting fluid towards an infinite wall is solved in the presence of a magnetic field which is aligned with the flow far from the wall. The problem has two dimensionless parameters-- ε, the magnetic Prandtl number, and β, the square of the ratio of Alfven velocity to fluid velocity far from the wall. The problem has a similarity solution which reduces the governing equations to a system of coupled ordinary differential equations which can be solved numerically. For extreme values of ε, both large and small, singular perturbation techniques are used to derive asymptotic expansions for the physically relevant quantities in the flow--the skin friction at the wall and the tangential component of magnetic intensity at the wall. Extensive comparisons are made between the asymptotic predictions and the numerical results with remarkably good agreement being obtained when ε ≥100 and ε ≤ 0.001. The flow is next combined with a shear flow to yield a flow impinging on the wall at some angle of incidence. The problem has a similarity solution and the resulting system of coupled differential equations is solved numerically. A series solution for the shear component of tangential stress at the wall for small and large values of $\epsilon$ is derived using singular perturbation techniques. The asymptotic expansions obtained are shown to be in excellent agreement with the numerical results when ε ≤ 0.001 and ε ≥100. The behavior of the flow near the wall is analyzed and the slope-ratio constant is evaluated for a variety of (ε,β) cases

Steady Incompressible Magnetohydrodynamic Flow Near a Point of Reattachment

The oblique stagnation-point flow of an electrically conducting fluid in the presence of a magnetic field is a highly nonlinear problem whose solution is of interest even in the simplest of geometries. The problem models the flow of a viscous conducting fluid near a point where a separation vortex reattaches itself to a rigid boundary. A similarity solution exists which reduces the problem to a coupled system of four ordinary differential equations which can be integrated numerically. The problem has two independent parameters, the conductivity of the fluid and the strength of the magnetic field. Solutions are tabulated for a variety of cases involving the two parameters. The geometry of the flow as well as that of the induced magnetic field is determined near the point of reattachment. © 1998 American Institute of Physics

Promoting Partnership, Cultivating Colleagueship: The SUMMIT-P Project at Norfolk State University

Norfolk State University (NSU) is the only public Historically Black College and University (HBCU) member institution in SUMMIT-P. At NSU, a strong collaboration between the Department of Mathematics and its partner discipline, the Department of Engineering, has been established for the Calculus I and Differential Equations classes as part of the SUMMIT-P project. In this paper, we record a brief history of this collaboration project at NSU, the various structures within the SUMMIT-P Project, the site visit that occurred in Spring 2019, and how recent activities helped guide the direction of the project at NSU

The Effect of Perioperative Dimethyl Sulfoxide Efficacy on Regional and Local Flaps Viability

Background: The purpose of this study was to analyze the effects and results of dimethyl sulfoxide (DMSO) usage on viability and perfusion of local and regional flaps in rabbits, via this study we are going to conclude whether DMSO could be effective after flap operations in human or not. Materials and Methods: Local and regional DMSO spray was used on rabbit’s dorsum flaps immediately after the operation and once per day up to 7 days post-op in 14 rabbits, divided equally to control group (saline solution spray) or experiment group (DMSO spray). The results were compared 3 and 7 days after operations. Results: There were improved results attributed to the DMSO effects regarding flap survival Conclusion: We concluded that topical application of DMSO reduces skin flap ischemia in rabbits and we highly advise the use of it after operations in which skin flaps are created

Evaluation of Staggered Osteotomy in Surgical Treatment of Trigonocephaly

Introduction: undiagnosed metopic synostosis (Trigonocephaly) have many complications for infants such as Brain damage and cognitive & behavioral disorders, they also result in poor aesthetic features. There are many surgical techniques for this malformation which have their advantages and disadvantages; but with this new method (staggered osteotomy) we can solve some of these problems and minimize damages.Materials and Methods:  In this study, 20 infants with metopic synostosis underwent surgery in Mofid Children Hospital, Tehran.  The minimum age of our patients was 4 months and the maximum was 9 months with an average of 6.72 months. Their diagnosis was confirmed with clinical symptoms & signs also with CTscan and paraclinical findings. Age and weight before and after surgery and anthropometric indices including: biparietal width and frontal width were recorded and reported.Results: We found significant differences in anthropometric indices before & after surgery such as lowering of biparietal width after surgery and elevation of frontoparital index after surgery. Since in this procedure, we don’t separate the frontal bone segments and it keeps its frame, less plaques and screws are needed which will decrease the costs of surgery and the surgical time is much less than other techniques. Last but not the least, the satisfactions of parents were high and there was no need for secondary surgery.Conclusion:Based on all the perfect results we got , it is safe to say that staggered osteotomy as a surgical method for correction of trigonocephaly is useful and we can use it as a new method in correction of  metopic synostosis

Experimental study: experimental evaluation of phospholipid system containing doxorubicin HCL for use in chemotherapy

Introdution: Common cancer treatment methods have many side effects. Therefore, the use of new methods for drug delivery to cancer cells is necessary. In the present study, nano formulations of lipid carriers containing doxorubicin have been synthesized and its physicochemical properties have been investigated. Methods: The present study was an experimental study. The liposomal systems were synthesized by the method of thin-film hydration and using Tween-20, cholesterol and soybean phosphatidylcholine. After loading Doxorubicin drug into the liposomes, physiochemical properties of nano-carriers were determined from the perspective of encapsulation efficiency, drug release profile under healthy and cancerous cells condition, hydrodynamic diameter, zeta potential, morphology and IR spectra. Results: The liposomal system had 132.9 nm in diameter, the encapsulation 93.74% and -38.73±0.18mV zeta potential. The maximum release of drug from the nano-carrier under conditions 37°C, pH=7.4 and 42°C, pH=5.4 and 37°C, pH=5.4 after 72 hours was 36.54% and 74.18% and 55.9% respectively. SEM and IR assessments revealed spherical morphology and the absence of chemical interaction between nano-carrier and drug. Conclusion: The result of this research indicates that the liposomal system, having the appropriate physiochemical properties, has not changed the chemical nature of drug and thus can be a suitable and semi-targeted carrier for doxorubicin

A Study on Causes of Azoospermia in Urology Clinic of Yasuj University of Medical Sciences

ABSTRACT: Introduction & Objective: Azoospermia means no sperm in semen. It may be due to hormonal imbalance, any disorder in production of sperm, or might be due to obstruction in sperm pathway from testis till ejaculatory ducts. This study was performed to determine the causes of azoospermia in infertile male, referred to Yasuj clinic of urology. Material & Methods: This study was done during more than 2 years beginning from May 2004. Patients with at least two consecutive azoospermic semen analyses were included in this study after a complete history taking, physical examination, hormonal study (FSH, LH, prolactine, testosterone), vasography, testis biopsy and genetic evaluation. Results: Among 842 infertile men,172 patients (20.4%) were azoospermic. 28 patients (16.3%) with obstructive azoospermia and 144 patients (83.7%) with non obstructive azoospermia were detected. Common causes of non obstructive azoospermia were as follow: idiopathic 68 patients (39.53%), atrophied testes 40 patients (23.25%) , sertoli cell only 34 (19.76%) patient, undescended testes 28 (16.27%) patients and post chemotherapy in 2 (1.16%) patients. Causes of obstructive azoospermia were obstruction of epididymis or vasa deferens in 24 patients (86%) and congenital bilateral agenesis of vasa deferens in 4 patients (14%). Conclusion: Results of this study showed that about 20% of infertile men are azoospermic and the most common type of azoospermia is non obstructive type

CBCJ specimen

This dataset includes Excel files of numerical analysis resultsTHIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV

An evaluation on sedimentary facies, hydrochemistry condition and degree of consolidation in travertine deposits of the Nodushan Spring, northwestern of Yazd

Abstract This study tries to evaluate the geological properties of a travertine spring and its related deposits. The identification of sedimentary facies of springs could be applied as a method to distinguish the type of travertine springs. Therefore in this study, that method has been used for the determination of the type of the spring. Results obtained from facies analysis reveal 13 sedimentary facies that could be categorized into two groups including organic facies which contain five facies and abiotic facies containing eight facies. These facies show the character of hydrothermal spring and set the spring in the thermogenic group. The chemical composition analysis of the spring water represents the facies of NaCl, Na-Ca-SO4-Cl can be considered to be precise chemical facies. The presence of calcium and sulfate as the second most frequent ions, after sodium and chloride, may initially indicates the existence of gypsum or anhydrite deposits in this area. On the other hand, given the absence of sulfate-bearing sediments in this region, it can be concluded that the interaction of water and magmatic systems was the most important source of sulfate in the spring water. Based on the rock mechanical properties of the travertine, it was revealed that with increasing age of the sediments their consolidation degree increases. The hardness of sediments shows an increasing trend by increasing distance from the spring vent. Keywords: Travertine, Sedimentary facies, Thermogene, Hydrochemistry, Yazd.   Introduction Travertine is one of the most well-known continental carbonate rocks, which has been highly regarded for its commercial-decorative quality. Travertine is made up of a variety of sediments that are formed through two main processes: first, carbonate sediments originating from running water that is lithified during sedimentation (abiotic crystals and facies caused by microbial activity). Second, sediments that were deposited like marine carbonates in an aquatic setting such as lakes, swamps, streams, and temporary ponds. To eliminate the complexities of travertines, a classification on hot spring sediments has been proposed to identify the relationships between sedimentary processes and fabrics of sediments. Numerous studies have considered the influence of water chemistry, as well as the dynamics of flow at the source of the springs, on the sedimentation mechanism. Underground water chemistry is one of the essential parameters for evaluating the environmental characteristics of each region. This paper aims to investigate the sedimentary facies of travertine deposits of the Nodushan Spring in the northwest of Yazd in central Iran. Moreover, the relationships between these facies and the mechanism of their formation based on the facies, hydrochemistry condition, and mechanical properties are examined.   Material & Methods According to the Aqda geological map (1:100,000), the location of the study area was determined and geological features were considered. A total of 42 samples were collected and the necessary field photos from macroscopic features of the region were captured. After that, thin sections of the samples were studied by a polarizing microscope. In this study, three samples of water collected from the travertine ponds of this spring have been analyzed for hydrochemical properties. Various physicochemical parameters have been analyzed, including calcium (Ca), sodium (Na), potassium (K), magnesium (Mg), ammonium (NH4), bicarbonate (HCO3), sulfate (SO4), chloride (Cl), fluoride (F), nitrate (NO3), pH, temperature, turbidity, as well as total alkalinity, hardness and dissolved solids (TDS). The degree of consolidation of the samples was also measured by Schmidt hammer to investigate its relationship with travertine fabrics.   Discussion of Results & Conclusions The deposition of carbonate sediments in the form of travertine in hot springs reflects the characteristics of a tectonic-geothermal system. Of course, sedimentation is not only affected by water temperature, but also by the saturation of calcium, flow rate, water flow mechanics, as well as the presence of sulfur compounds, which affect the environmental conditions of the environment. Facies analysis indicates that 13 sedimentary facies could be categorized in two groups: organic facies which contain five facies (clotted micrite, stromatolite bindstone, microbial rafts, oncoid facies, and dendritic shrubs) and abiotic facies comprise eight facies (crystalline crusts, fan-ray crystals, feather-like crystals, coated bubbles, spheroid facies, and needle-shaped shrubs). These facies show the character of hydrothermal spring and put the spring in the thermogenic group.  It generally seems that crystalline facies have been largely influenced by abiotic sedimentation, while laminar facies were formed under the influence of microbial activity related to hot springs. Rapid sedimentation rates lead to the dominance of abiotic processes, while slow rates create more microbial activities that are effective in sedimentation processes. The chemical composition analysis of the spring water represents the facies of NaCl, Na-Ca-SO4-Cl can be considered to be precise chemical facies. The presence of calcium and sulfate as the second most frequent ions - after sodium and chloride - it may initially indicate the presence of gypsum or anhydrite sediments in this area. On the other hand, given the absence of sulfate-bearing sediments in this region, it can be concluded that the interaction of water and magmatic systems is the most important source of sulfate in spring water. Also, changes in Na/(Na + Ca) and Cl/(Cl + HCO3) relative to the amount of TDS in the analyzed water sample show that the predominant process controlling the water quality of this spring is evaporative processes, which occurs as a result of direct connection of water with atmosphere after leaking from the spring. Based on the mechanical properties of the travertine, it was revealed that with increasing age of the sediments their consolidation degree increased. The hardness of sediments shows an increasing trend by increasing distance from the spring vent. Moreover, it was found that major discontinuities observed in the wall of the valley not effective role in drainage of surface waters, so that formation of the sediments was directly related to the spring wate