268 research outputs found
Effect of Mass Transfer on Aeroheating in Hypersonic Chemically Reacting Boundary Layers
Heat flux characterization of high-enthalpy boundary layer flows is key to optimize the performance and design of Thermal Protection System of next generation aerospace vehicles [1]. At atmospheric entry hypersonic speeds, ablation as well as surface catalycity impact boundary layer aeroheating. Out-gassing occurring from an ablative surface in planetary entry environment introduces a rich set of problems in thermodynamic, fluid dynamic, and material pyrolysis. Ablation leads to out-gassing and surface roughness, both of which are known to affect surface heating in hypersonic chemically reacting boundary layers via three main routes: gas blowing into the boundary layer from the wall, changing the surface heat transfer due to wall-flow chemical reactions, and modifying surface roughness via ablative processes
Effect of Out-Gassing on the Onset of Hypersonic Boundary Layer Transition
Prediction and control of the onset of transition and the associated variation in aerothermodynamic parameters in high-speed flows is key to optimize the performance and design of Thermal Protection Systems (TPS) of next-generation aerospace vehicles [1]. Boundary Layer Transition (BLT) characteristics can influence the surface heating budget determining the TPS thickness and consequently its weight penalty. Ablative heatshields are designed to alleviate the high heat flux at the surface through pyrolysis of their polymeric matrix and subsequent fiber ablation [2]. Pyrolysis leads to out-gassing and non-uniform ablation lead to surface roughness, both of which are known to influence the transition process. An ablator impacts BLT through three main routes: gas injecting into the boundary layer from the wall, changing the surface heat transfer due to wall-flow chemical reactions, and modifying surface roughness [3]. In preparation to Mars 2020 mission post-flight analysis, the predictive transition capability has been initiated toward hard-coupling porous material response analysis and aerothermal environment calculation
Superior Performance of Magnetic Nanoparticles for Entrapment and Fixation of Bovine Serum Albumin In-Vitro
BACKGROUND: In recent years, extensive studies have been performed on magnetite nanoparticles (MNPs) and their applications, which have shown the current project to be one of the major applications by laboratory results.METHODS: The nanoparticles synthesized in this project were deposited by the co-precipitation method, which structure was identified by analyzers such as SEM, FT-IR, and EDX. The aim of this project is the adsorption and fixation of biomolecule (BSA (bovine serum albumin) protein on the surface of magnetic nanoparticles.RESULTS: The adsorption results by electrophoresis and spectrophotometric analyzers showed an absorption rate above 55% ie; 55% of the protein is fixed on the MNPs nanoparticles. This absorption is due to the high level of functionality of magnetic nanoparticles for adsorption of protein. The results of the EDX analysis also show the possible electrostatic bonding between the nanoparticles and the protein, this is derived from –OH with –NH2 groups of the nanobiocompound (MNPs /protein). After bonding, the two are easily separated.CONCLUSION: In this project, the Fe3O4 nanoparticles was synthesized and identified by SEM, FT-IR, and EDX analyzers and finally reacted with the BSA protein (for the absorption of protein on MNPs) under experimental conditions at a standard temperature of 25° C. The results showed that about 55% of the protein was fixed on magnetic nanoparticles
Investigating the factors affecting the competitiveness of small and medium companies in Sanandaj
The present study is conducted to investigate the factors affecting the competitiveness of small and medium companies in Sanandaj city, Iran. 177 small and medium companies were investigated and 130 questionnaires were prepared by using stratified random sampling and 121 experts and administrators have responded to the questionnaire. According to the theoretical principles, samples are provided that the research findings confirmed the model and result of path analysis showed the direct effect of variables of industry and specialized environment on companies' competitiveness. In the present study in order to analyze the data obtained from the questionnaires, due to the statistical needs the social sciences statistical software, structural equation of partial least squares model methods were used in form of descriptive and correlations statistics. Finally, these factors were prioritized by using the Friedman test. According to the obtained results from this research, the mean of the existing competitors' rate was 4.41 which has the lowest rate in affecting the competitiveness of small and medium companies. But we can see the highest rates of influencing the competitiveness of small and medium companies in the management dimension with the mean rate of 7.70. Therefore, the highest and lowest influencing rate can be seen in both industry and specialized environment sectors by comparing the mean of rates
Investigating the factors affecting the competitiveness of small and medium companies in Sanandaj
The present study is conducted to investigate the factors affecting the competitiveness of small and medium companies in Sanandaj city, Iran. 177 small and medium companies were investigated and 130 questionnaires were prepared by using stratified random sampling and 121 experts and administrators have responded to the questionnaire. According to the theoretical principles, samples are provided that the research findings confirmed the model and result of path analysis showed the direct effect of variables of industry and specialized environment on companies' competitiveness. In the present study in order to analyze the data obtained from the questionnaires, due to the statistical needs the social sciences statistical software, structural equation of partial least squares model methods were used in form of descriptive and correlations statistics. Finally, these factors were prioritized by using the Friedman test. According to the obtained results from this research, the mean of the existing competitors' rate was 4.41 which has the lowest rate in affecting the competitiveness of small and medium companies. But we can see the highest rates of influencing the competitiveness of small and medium companies in the management dimension with the mean rate of 7.70. Therefore, the highest and lowest influencing rate can be seen in both industry and specialized environment sectors by comparing the mean of rates
Regeneration ability and genetic transformation of root type chicory (Cichorium intybus var. sativum)
To develop an efficient protocol for shoot regeneration of root chicory (Cichorium intybus var. sativum), some factors, including different concentrations of plant growth regulators in Murashige and Skoog (MS) medium, type of explants and genotypes were evaluated. Initiation of callusing were best achieved in MS medium supplemented with 1-naphthaleneacetic acid (NAA) (0.1 mg l-1) plus 6-Benzylaminopurine (6-BAP) (1 mg l-1), indole-3-acetic acid (IAA) (0.01 mg l-1) plus 6-BAP (1.0 mg l-1), and IAA (0.5 mg l-1) plus (0.5 mg l-1) 6-BAP combinations on leaf and cotyledon explants. Explant-derived calli were able to produce multiple adventitious shoots in MS medium containing IAA (0.5 mg l-1) plus 6-BAP (0.5 mg l-1). MS medium containing indole-3-butylric acid IBA (1 mgl-1) efficiently induced rooting on elongated shoots. Various responses to the number of generated shoots were observed when regeneration abilities of different chicory cultivars were examined. Among root and “Witloof” cultivars, ‘Melci’ and ‘Hera’ belong to the root cultivars and exhibited higher shoot regeneration ability. Using the optimized regeneration method, genetic transformation of ‘Melci’ with Agrobacterium tumefaciens strain C58C1 RifR (pGV2260) (pTJK136) was successfully carried out. Histochemical GUS assay, polymerase chain reaction (PCR) and reverse transcription-polymerase chain reaction (RT-PCR) analysis of putative transformed plants confirmed successful integration of the T-DNA into the chicory genome. Expression of the neomycine phosphotransferase (NPTII) in the regenerated plants was also shown by well-developed roots on root inducing medium containing 100 mg l-1 kanamycin. This simple, efficient and reproducible protocol could be useful for inducing somaclonal variation and genetic modification of root chicory cultivars to broaden genetic variation and transferring of important genes
Decoding the genetics of speech and language: Genetic insight into the functional elements
زمینه و هدف: مدت زمان مدیدی است که تصور می‌شود توانایی انسان برای کسب قابلیت زبان توسط ساختار ژنتیکی او کد می‌شود. با این حال، تنها به تازگی شواهد ژنتیکی متعددی برای اثبات اساس ژنتیکی احتمالی ِزبان در دسترس است. در طول دهه گذشته، واریانت‌های ژنتیکی مختلفی شناسایی شده‌اند که ممکن است افراد را به جنبه‌های مختلف اختلالات زبان مستعد کنند. اختلالات زبان و گفتار طیف گسترده‌ای از شرایط با فنوتیپ‌های هتروژن و همپوشان را پوشش می‌دهند که می‌توانند علل پیچیده‌ی ژنتیکی و محیطی داشته باشند. ر‌وش بررسی: در این مطالعه مروری، جستجوی نظام ‌مندی در پایگاه‌های الکترونیکی معتبر (Googlescholar, Pubmed, Sciencedirect و Scopus) انجام شد و مقالات انگلیسی مرتبط با موضوع به وسیله‌ی انتخاب کلمات کلیدی زبان، ژنتیک، ژن FOXP2، ژن‌های کاندید و غیره مورد جستجو و استخراج قرار گرفتند. یافته ‌ها: در این مقاله‌ی مروری، بحث می‌کنیم که چگونه شناسایی و مطالعه‌ی ژن‌های خاص، از جمله: FOXP2، CNTNAP2، FOXP1، DCDC2، DYX1C1، ROBO1، KIAA0319، ATP2C2، CMIP، CYP19A1، SRPX2، MRPL19، C2ORF3 و DOCK4، می‌تواند درک ما از سبب‌شناسی اختلالات تکلم و اساس بیولوژیکی اکتساب زبان را افزایش دهد. نتیجه ‌گیری: شناسایی ژن‌های مرتبط با فنوتیپ‌های زبان و تکلم، و توصیف عملکردهای طبیعی و نابجای این ژن‌ها در سال‌های اخیر، جزئیات پیچیده‌ی مکانیسم‌های مولکولی و شناختی را مشخص کرده و دیدگاه ارزشمندی از اساس بیولوژیکی زبان ارائه کرده است
An overview on the evolution of language and genetics of speech disorders
Language, as an exclusive salient of human kind, is the requisite of development and formation of the human society; thus, it is at the topmost of human evolutionary features. Language and speech can be studied in various fields such as biology. Biolinguistics is an interdisciplinary field in which biological development of language is studied. It aims to find the functioning cycle in mind that enables humans to perceive the principles and bases of language. Language genetics, a subfield of biolinguistics, traces genetic factors in the formation and perception of language. Although a variety of theories have been introduced to explain the origins of language, considering recent studies, acquiring essential genetic abilities for speaking are undoubtedly of the most crucial necessities of this skill. Researchers have recently found defective genes in a wide spectrum of language disorders, through which they strongly confirm that speech systems rely on these genes to function properly. However, there is no report on a study which answers this question clearly: considering the origins of language and human evolution, is the proper function of genes, genetic structures, and general requirements necessary for speaking? The evolution of language and genetics of speech disorders along with the outstanding improvements and recent studies are discussed in this review article. © 2014, Isfahan University of Medical Sciences(IUMS). All rights reserved
Designing a Reverse Logistics Network for End-of-Life Vehicles Recovery
The environmental factors are receiving increasing attention in different life cycle stages of products. When a product reaches its End-Of-Life (EOL) stage, the management of its recovery process is affected by the environmental and also economical factors. Selecting efficient methods for the collection and recovery of EOL products has become an important issue. The European Union Directive 2000/53/EC extends the responsibility of the vehicle manufacturers to the postconsumer stage of the vehicle. In order to fulfill the requirements of this Directive and also efficient management of the whole recovery process, the conceptual framework of a reverse logistics network is presented. The distribution of new vehicles in an area and also collecting the End-of-Life Vehicles (ELVs) and their recovery are considered jointly. It is assumed that the new vehicles distributors are also responsible for collecting the ELVs. Then a mathematical model is developed which minimizes the costs of setting up the network and also the relevant transportation costs. Because of the complexity of the model, a solution methodology based on the genetic algorithm is designed which enables achieving good quality solutions in a reasonable algorithm run time
The Effect of Treatment with an Herbal Formulation of Salvia hydrangea, Citrus aurantium, Lipia citriodora, and Elm Bark on the Intensity of Tinnitus: A Clinical Trial
Background: Tinnitus is a symptom of an underlying medical condition that is associated with hearing loss in humans. It is a subjective disease where patients hear voices that others cannot hear. Increase in noise pollution, growing development of communication devices, and the long-ranging 8-year war in our country have further accelerated the spread of this disorder. Given that no definitive medical or surgical treatment has been confirmed for this condition, new research to improve treatment options is urgent.Aim: The purpose of this study was to assess the effect of a formulation prepared from Salvia hydrangea, Citrus aurantium, Lipia Citriodora, and elm bark on the status of tinnitus.Methods: In this single-blind clinical trial, 144 patients with tinnitus were selected based on pre-defined inclusion criteria and then randomly divided into 3 groups: herbal formulation, cinnarizine, and placebo groups, where the frequency and intensity of tinnitus was measured based on the Tinnitus Handicap Inventory (THI) and Visual Analogue Scale (VAS) criteria before and on 28 and 56 days post treatment. Data were analyzed by the statistical software SPSS version 16, repeated measurement, one-way, and X2 for comparison within and among groups, with the significance level set at p < 0.05. Results: comparably, tinnitus based on THI criteria differed among the 3 groups on 28 and 56 days of intervention, where the difference was statistically significant (p < 0.05). This difference was more significant between the cinnarizine and placebo groups. The mean severity of tinnitus, based on the VAS score, differed among the three groups on 28 and 56 days after intervention, although the difference was not statistically significant. Conclusion: Herbal formulation was effective on tinnitus alleviation, but its effect was not superior to that of conventionally used chemical drug cinnarizine
- …