Добірка наукової літератури з теми "532.135:538.4"

C/SiC composites have widely application prospects in the field of aeronautic and aerospace for their excellent properties. The joining of C/SiC composites is a key to fabricate large and complex components. In this paper, 1D C/SiC pins were prepared by precursor infiltration and pyrolysis (PIP) process and used to join C/SiC composites by Slurry react (SR) and PIP process. The shear strength of the C/SiC pins with different carbon fiber volumes was investigated with the maximum shear strength as high as 339.46MPa. Influences of C/SiC pins on the joining properties of C/SiC composites were studied. The shear strength and flexural strength of C/SiC-C/SiC joining are improved from 9.17MPa and 30.41MPa without pins to 20.06MPa and 75.03MPa with one C/SiC pin (diameter 2mm), respectively. The reliability of C/SiC-C/SiC joining is also improved with C/SiC pins in that the fracture mode changes from catastrophic without pins to non-catastrophic. The SEM photos show a strong bond between joining layer and C/SiC composites without obvious interface.

A 72-year-old man undergoing continuous ambulatory peritoneal dialysis (CAPD) for chronic renal failure and who had undergone right upper lobectomy for lung adenocarcinoma (pT2aN0M0) 2 years ago was admitted for recurrence of lung cancer presenting as multiple brain metastases. An epidermal growth factor receptor mutation analysis of his lung cancer revealed a deletion of 15 nucleotides (E746-A750) in exon 19. After whole-brain radiotherapy, we started daily administration of 250 mg gefitinib under the continuation of CAPD and performed a pharmacokinetic analysis. We speculated that the plasma concentration of gefitinib reached the steady state at least by day 16 after the start of gefitinib (626.6 ng/ml at trough level). On day 46, the plasma concentration was 538.4 ng/ml at trough level and the concentration in the peritoneal dialysis fluid was 34.6 ng/ml, suggesting that CAPD appeared to have little effect on the pharmacokinetics of gefitinib. During gefitinib therapy, there were no significant adverse events except for grade 2 diarrhea. Gefitinib could be safely administered to a patient undergoing CAPD.

The type of soil at the location of the hotel building is a type of medium land (D). The applications used in this study are ETABS V16.1 and AutoCAD. Based on the PUSKIM website, the Ss and S1 Bogor City were 0.881 and 0.356, respectively. Based on the results of the analysis of the application ETABS V16.1 obtained fewer reinforcement design results than the existing reinforcement. The maximum nominal moment of the beam is 508.3 kNm while the ultimate moment is 498.4 kNm. The maximum nominal shear force of the beam is 565.9 kN while the ultimate shear force is 538.4 kN. The maximum nominal moment of the column is 1488.5 kNm while the maximum ultimate moment is 1478 kNm. The maximum nominal axial force of the column is 6291 kN while the maximum ultimate axial force is 6287 kN. The maximum nominal bending moment of the floor plate is 41.3 kNm while the maximum ultimate moment is 39.9 kNm. The maximum nominal shear force of the floor plate is 234.7 kN while the maximum ultimate shear force is 228.9 kN. The nominal shear force of shear wall is 8238.5 kN while the ultimate shear force is 8194.7 kN. Based on the internal forces, the building that has been built is in accordance with the plan so that it is safe to withstand earthquake loads.

The aim of this study is to identify and investigate levels of toxic heavy metals in PM2.5 fractioned road dust to better understand the associated inhalation risk and potential health impacts. To achieve this aim, concentrations of seven traffic generated heavy metals (Cu, Pb, Zn, Cd, Ni, Sb, and Cr) were determined in the PM2.5 fraction of road dust samples from four different locations (offices, residential, hospital, and school) in two cities (Karachi and Shikarpur) of Pakistan using ICP-MS. The average concentration values of heavy metals in Karachi were as follows: 332.9 mg/kg Cu, 426.6 mg/kg Pb, 4254.4 mg/kg Zn, 62.3 mg/kg Cd, 389.7 mg/kg Ni, 70.4 mg/kg Sb, 148.1 mg/kg Cr, whereas the average concentration values of heavy metals in Shikarpur were 245.8 mg/kg Cu, 538.4 mg/kg Pb, 8351.0 mg/kg Zn, 57.6 mg/kg Cd, 131.7 mg/kg Ni, 314.5 mg/kg Sb, 346.6 mg/kg Cr. The pollution level was assessed through two pollution indices enrichment factor (EF) and geoaccumulation index (Igeo). These indices showed moderate to extreme level pollution in studied areas of both cities. The health risk assessment through inhalation contact was conducted according to the United States Environmental Protection Agency’s (USEPA) model for children and adults. Both non-cancerous and cancerous risks were characterised in the road dust samples for each location. As yet, there is not a single study on the concentrations of heavy metals in PM2.5 fractions of road dust in Karachi and Shikarpur, findings of this research will facilitate researchers for further investigations in current field.

Purpose To study the incidence and treatment outcomes of hepatocellular carcinoma (HCC) detected in an intensive surveillance program (ISP) of hepatitis B virus (HBV) carriers. Patients and Methods We screened 1,018 HBV carriers by serum alpha-fetoprotein (AFP) measurement and abdominal ultrasonography (AUS). Patients with an abnormal AFP level or AUS result were enrolled in an ISP that included Lipiodol computed tomography followed by AFP measurement/AUS every 3 months for 2 years and then every 6 months thereafter. The rest were on routine surveillance for 2 years. Results A total of 9,849 serum AFP measurements and 3,053 AUSs were performed. After a median follow-up of 4.12 years, we diagnosed 24 HCCs among 78 patients with abnormal screening test results at enrollment (group A); 23 HCCs among 93 patients with only abnormal surveillance test results during follow-up (group B); and nine HCCs among 847 patients with 2 years of normal surveillance (group C). Annual incidence of HCC in the ISP was 760.2 (95% CI, 538.4 to 1,073.7) per 100,000. Mean tumor sizes were 3.02, 2.91, and 4.82 cm in groups A, B, and C, respectively (P = .01). Tumor resection rate of the ISP was 36.2%, although another 29.8% of the patients were eligible for locoregional ablative therapy. Conclusion This study illustrated that a high incidence of relatively small HCCs may be detected by using intensive surveillance of high-risk HBV carriers. However, the surgical resection rate was low, and we were not able to demonstrate clinical benefit with the early detection. Future surveillance studies should consider incorporation of therapy aimed at long-term control of small-sized tumors.

We determined the roles of maximal systolic elastance (Emax) and theoretical maximum flow (Qmax) in the regulation of cardiac pumping function in early streptozotocin (STZ)-diabetic fats. Physically, Emax can reflect the intrinsic contractility of the myocardium as an intact heart, and Qmax has an inverse relation to the systolic resistance of the left ventricle. Rats given STZ 65 mg/kg l.v. (n = 17) were divided into two groups, 1 week and 4 weeks after induction of diabetes, and compared with untreated age-matched controls (n = 15). Left ventricular (LV) pressure and ascending aortic flow signals were recorded to calculate Emax and Qmax, using the elastance-resistance model. After 1 or 4 weeks, STZ-diabetic animals show an increase in effective LV end-diastolic volume (Veed), no significant change in peak iso-volumic pressure (Pisomax), and a decline in effective arterial volume elastance (Ea). The maximal systolic elastance Emax is reduced from 751.5 ± 23.1 mmHg/ml in controls to 514.1 ± 22.4 mmHg/ml in 1- and 538.4 ± 33.8 mmHg/ml in 4-week diabetic rats. Since Emax equals PisomaxVeed, an increase in Veed with unaltered Pisomax may primarily act to diminish Emax so that the intrinsic contractility of the diabetic heart is impaired. By contrast, STZ-diabetic rats have higher theoretical maximum flow Qmax (40.9 ± 2.8 ml/s in 1- and 44.5 ± 3.8 ml/s in 4-week diabetic rats) than do controls (30.7 ± 1.7 ml/s). There exists an inverse relation between Qmax and Ea when a linear regression of Qmax on Ea is performed over all animals studied (r= 0.65, p < 0.01). The enhanced Qmax is indicative of the decline in systolic resistance of the diabetic rat heart. The opposing effects of enhanced Qmax and reduced Emax may negate each other, and then the cardiac pumping function of the early STZ-diabetic rat heart could be preserved before cardiac failure occurs.

The main objectives of this study were to evaluate the short-term effects of resisted sprint and plyometric training on sprint performance together with lower limb physiological and functional performance in collegiate football players. Ninety collegiate football players participated in this three-arm, parallel group randomized controlled trial study. Participants were randomly divided into a control group and two experimental groups: resisted sprint training (RST) (n = 30), plyometric training (PT) (n = 30), and a control group (n = 30). Participants received their respective training program for six weeks on alternate days. The primary outcome measures were a knee extensor strength test (measured by an ISOMOVE dynamometer), a sprint test and a single leg triple hop test. Measurements were taken at baseline and after 6 weeks post-training. Participants, caregivers, and those assigning the outcomes were blinded to the group assignment. A mixed design analysis of variance was used to compare between groups, within-group and the interaction between time and group. A within-group analysis revealed a significant difference (p < 0.05) when compared to the baseline with the 6 weeks post-intervention scores for all the outcomes including STN (RST: d = 1.63; PT: d = 2.38; Control: d = 2.26), ST (RST: d = 1.21; PT: d = 1.36; Control: d = 0.38), and SLTHT (RST: d = 0.76; PT: d = 0.61; Control: d = 0.18). A sub-group analysis demonstrated an increase in strength in the plyometric training group (95% CI 14.73 to 15.09, p = 0.00), an increase in the single leg triple hop test in the resisted sprint training group (95% CI 516.41 to 538.4, p = 0.05), and the sprint test was also improved in both experimental groups (95% CI 8.54 to 8.82, p = 0.00). Our findings suggest that, during a short-term training period, RST or PT training are equally capable of enhancing the neuromechanical capacities of collegiate football players. No adverse events were reported by the participants.

My thesis concerns two areas of current research in magnetism, with the common experimental technique of elastic and inelastic neutron scattering on powders and single crystals. The first topic is concerned with rare earth intermetallic compounds with unfilled 4f shells. When a rare earth element with an unfilled shell is placed in an environment with surrounding charges, the crystal electric field acts to lift the J-fold degeneracy. Determination of the Crystal Electric Field (CEF) ground state and excited states are important to understand the complex and interesting low temperature phase diagrams these compounds exhibit. This will be discussed for the rare earth intermetallic compound TmGa3. The other area of my thesis concerns one dimensional Heisenberg antiferromagnetic quantum chains systems. Due to the one-dimensional lattice and low spin, quantum fluctuations play an important role in these systems. From the nature of the lattice, the interactions could give rise to magnetic frustration, resulting in interesting ground states. I will discuss results on the binary halides CuCl2, CuBr2 and on the quaternary oxide LiCuVO4. To measure the thermal properties of the investigated systems, a quasi-adiabatic Nernst type calorimeter was constructed and commissioned. I will describe the design and the properties of the calorimeter.

Магістерська дисертація на тему “Удосконалення ендопротезу колінного суглобу за рахунок використання магнітно-реологічного демпфера”, складається з __3__ розділів, обсяг пояснювальної записки __117__ сторінок основного тексту, включає _75__ рисунків і _31__ таблиця, та __8__ плакатів графічного матеріалу. Метою роботи є підвищення стабільності МРД протезу колінного суглобу в змінних умовах експлуатації. Для досягнення поставленої мети було сформульовано ряд задач: - провести аналіз існуючих конструкцій протезів колінних суглобів; - теоретично обґрунтувати та створити математичні моделі робочих процесів та дослідити вплив температури та напруженості магнітно поля на робочі характеристики МРД; - розробити експериментальну установку для перевірки та уточнення математичних моделей МРД; - провести експериментальні дослідження; - розробити рекомендації щодо створення адаптивних демпферів з урахуванням результатів отриманих при виконанні роботи. Перший розділ даної роботи присвячено аналітичному дослідженню впливу зовнішніх та внутрішніх факторів на демпфери протезу та методи адаптації під них. Другий розділ присвячено розробці математичної моделі яка описує залежність впливу температури на робочу характеристику демпфера. Третій розділ включає в себе створення стенду для проведення відповідних експериментальних досліджень, представлена схема та необхідна апаратура, що дозволили створити безпосередньо стенд для досліджень впливу температури та тиску робочого середовища на робочі характеристики МРД суглобу. Розробити методи експериментальних досліджень. Проведено серії експериментів, для визначення впливу перепаду тиску та температури на робочу характеристику. Об’єктом дослідження в даній роботі є процес функціонування МРД протезу колінного суглобу, а саме його дроселя при різних умовах експлуатації. Предметом дослідження є зв'язок конструктивних параметрів провідності регульованого дроселя та зміни температури робочої рідини. Науковою новизною даного дослідження є запропоновані аналітичні залежності, що відображають зміну витрати від прикладеної сили струму (магнітного поля). Розроблена уточнена математична модель процесу демпфування протезу колінного суглобу. Перелік ключових слів: Демпфер, протезування, моделювання в SolidWorks, адаптивні властивості, дросель. Для дослідження МРД використовувався пакет прикладних програм „MatLab ”, в додатку до нього „Simulink”. Результати дослідження дозволяють вдосконалити конструкцію МР демпфера та зменшити температурний фактор на його характеристики. Публікаціїї. За матеріалами магістерської дисертації було опубліковано 4 праці, а саме 3 тези доповідей на міжнародних науково-технічних конференціях студентів.
The master's thesis on the theme "Improvement of knee joint endoprosthesis due to the use of magnetic-rheological damper" consists of __3__ sections, the volume of the explanatory note __117__ pages of the main text, includes _75__ drawings and _31__ tables, and __8__ posters of graphic material. The aim of the work is to increase the stability of the MRI of the knee joint prosthesis under varying operating conditions. To achieve this goal, a number of tasks were formulated: - to carry out an analysis of existing designs of knee joints; - theoretically substantiate and create mathematical models of work processes and investigate the influence of temperature and intensity of the magnetic field on the operating characteristics of the MRD; - to develop an experimental installation for checking and refinement of mathematical models of MRD; - to conduct experimental research; - to develop recommendations for the creation of adaptive damping taking into account the results obtained during the work. The first section of this paper is devoted to the analytical study of the influence of external and internal factors on the denture dampers and the methods of adaptation under them. The second section is devoted to the development of a mathematical model that describes the dependence of temperature influence on the performance of the damper. The third section includes the creation of a stand for conducting relevant experimental research, a diagram and the necessary equipment are presented, which allowed to create a stand directly for research on the influence of temperature and pressure of the working environment on the working characteristics of the MRD of the joint. Develop experimental research methods. A series of experiments was conducted to determine the effect of pressure drop and temperature on the performance. The object of the research in this paper is the process of functioning of the MRI of the knee joint prosthesis, namely, its chokes under different operating conditions. The subject of the study is the connection of the design parameters of the conductivity of the regulated choke and changes in the temperature of the working fluid. The scientific novelty of this study is the proposed analytical dependence, reflecting the change in flow rate from the applied current strength (magnetic field). The refined mathematical model of the process of damping the knee joint prosthesis is developed. Keyword list: Damper, Prosthesis, Modeling in SolidWorks, Adaptive Properties, Choke. To study MRD, a package of applications "MatLab", in addition to "Simulink" was used. The results of the study allow to improve the design of the MP damper and reduce the temperature factor on its characteristics. Publications On the materials of the master's thesis 4 papers were published, namely 3 theses of reports at international scientific and technical conferences of students.
Магистерская диссертация на тему "Совершенствование эндопротеза коленного сустава за счет использования магнитно-реологического демпфера", состоит из __3__ разделов, объем пояснительной записки __121__ страниц у основного текста, включает _75__ рисунков и _31__ таблиц, и __8__ плакатов графического материала. Целью работы является повышение стабильности МРД протеза коленного сустава в изменяющихся условиях эксплуатации. Для достижения поставленной цели был сформулирован ряд задач: - провести анализ существующих конструкций протезов коленных суставов - теоретически обосновать и создать математические модели рабочих процессов и исследовать влияние температуры и напряженности магнитного поля на рабочие характеристики МРД; - разработать экспериментальную установку для проверки и уточнения математических моделей МРД; - провести экспериментальные исследования; - разработать рекомендации по созданию адаптивных демпферов с учетом результатов полученных при выполнении работы. Первый раздел данной работы посвящен аналитическому исследованию влияния внешних и внутренних факторов на демпферы протеза и методы адаптации в них. Вторая глава посвящена разработке математической модели описывающей зависимость влияния температуры на рабочую характеристику демпфера. Третий раздел включает в себя создание стенда для проведения соответствующих экспериментальных исследований, представлена схема и необходимая аппаратура, позволившие создать непосредственно стенд для исследований влияния температуры и давления рабочей среды на рабочие характеристики М РД сустава. Разработаны методы экспериментальных исследований. Проведено серии экспериментов, для определения влияния перепада давления и температуры на рабочую характеристику. Объектом исследования в данной работе является процесс функционирования МРД протеза коленного сустава, а именно его дросселя при различных условиях эксплуатации. Предметом исследования является связь конструктивных параметров проводимости регулируемого дросселя и изменения температуры рабочей жидкости. Научной новизной данного исследования предложенные аналитические зависимости, отражающие изменение расхода от приложенной силы тока (магнитного поля). Разработана уточненная математическая модель процесса демпфирования протеза коленного сустава. Перечень ключевых слов: Демпфер, протезирование, моделирование в SolidWorks, адаптивные свойства, дроссель. Для исследования МРД использовался пакет прикладных программ "MatLab", в приложении к нему "Simulink». Результаты исследования позволяют усовершенствовать конструкцию МР демпфера и уменьшить температурный фактор на его характеристики. Публикации. По материалам магистерской диссертации было опубликовано 4 работы, а именно 3 тезис а докладов на международных научно - технических конференциях студентов.

Les pastilles supraconductrices peuvent produire des forts champs magnétiques très supérieurs aux aimants permanents. Plusieurs méthodes d’aimantation de ces pastilles existent néanmoins une seule est principalement utilisée pour les applications en génie électrique, l’aimantation par champ magnétique impulsionnel (Pulsed Field Magnetization). Afin de maîtriser l’aimantation de ces pastilles supraconductrices par PFM, nous avons étudié l’influence de la forme de l’inducteur sur le champ magnétique piégé où nous trouvons une influence significative de la forme de l’inducteur sur le champ piégé dans la pastille supraconductrice. Afin de prévoir la mise en oeuvre des pastilles supraconductrices dans des applications en génie électrique, nous avons étudié l’aimantation de ces pastilles dans un circuit magnétique et l’influence de ce circuit sur le champ piégé. Nous remarquons une nette amélioration du champ piégé dans la pastille en utilisant le circuit magnétique. Nous avons étudié, également, l’influence d’un champ démagnétisant impulsionnel et alternatif sur le champ piégé dans une pastille supraconductrice aimantée. Les dégradations observées ne montrent pas de contre-indication à l’utilisation des pastilles supraconductrices aimantées dans les applications en génie électrique
The superconducting bulks can produce very strong magnetic fields greater than those of permanent magnets can. Several methods of magnetization of the superconducting bulks exist, however one is mainly used for the electrical applications, the Pulsed Field Magnetization. In order to control the magnetization of the superconducting bulks by PFM, we studied the influence of the shape of the inductor on the trapped magnetic field where we find a significant influence of the shape of the inductor on the trapped magnetic field in the anticipate superconducting bulk. In order to the implementation of the superconducting bulk in the electrical applications, we studied the magnetization of these bulks in a magnetic core and the influence of this magnetic core on the trapped magnetic field. We notice an important improvement of the trapped magnetic field in the superconducting bulk by using the magnetic core. We studied also the influence of a pulsed and an alternating demagnetizing field on the trapped magnetic field in a superconducting bulk. The observed degradation does not show any contraindication to use the superconducting magnetic bulks in the electrical engineering applications

Il existe actuellement un important besoin en dispositifs électroniques dans le domaine des longueurs d’ondes millimétriques, tels que les circulateurs et les isolateurs fonctionnant dans la gamme de fréquence 30-100 GHz. Les aimants permanents qui garantissent la propagation de l’onde électromagnétique dans ces dispositifs comportent très généralement des éléments terres rares. En raison du coût à l’acquisition de ces éléments, d’une part, ainsi que de leur coût environnemental d’autre part, il existe une demande d’aimants permanents produits sans terres rares. Les ferrites durs peuvent présenter les propriétés demandées pour une intégration dans les dipositifs micoondes non réciproques. Ainsi, les particules de ferrite de baryum (BaM) possèdent un champ d’anisotropie magnétocristallin important, dirigé selon l’axe de facile aimantation. Un matériau autopolarisé, constitué d’un empilement de ces particules, peut donc présenter une aimantation permanente d’intensité suffisante pour les applications visées. De nombreuses méthodes d’élaboration de tels matériaux ont été mises au point. Cependant les mises en oeuvre de ces méthodes sont contraignantes. En revanche, nous avons mis au point dans le présent travail un processus de réalisation de ferrites de BaM massifs autopolarisés, dont l’aspect technologique est simple (basé sur des méthodes de chimie douce et des traitements thermiques adaptés), et très abordable financièrement. Les résultats obtenus sont très compétitifs (aimantation rémanente normalisée MR/MS comprise entre 0.87 et 0.90. Le champ coercitif HC atteint la valeur de 303 kA/m, rendant le matériau peu sensible aux effets démagnétisants), et permettent d’envisager la production de ces matériaux en vue d’applications à des fréquences allant jusqu’à 55 GHz
Presently, there is a critical need for millimeter wave devices, among which are non-reciprocal devices such as isolators and circulators, which operate in the frequency range from about 30 GHz to 100 GHz.Permanent magnets that ensure the propagation of the wave in such devices are for long based on rare-earth elements. Nowadays, the escalation of rare earths cost encourages to look for alternative materials containing much less, or no, rare earth elements selected from the most common and most available. Alternatively, hard ferrites may show the required potential for integration into non-reciprocal microwave devices. Barium ferrite (BaM) is a wellknown, high-performance, permanent magnet material with a large magneto-crystalline anisotropy along the c-axis of its hexagonal structure. A suitable form of barium ferrite for mm-wave applications is a magnetically oriented bulk material.Several constraining processing techniques were therefore set up to perform the alignment and compaction of plate hexaferrite particles. In contrast to these methods, the present study demonstrates the feasibility of simple alternative ways to provide highly oriented bulk compacts made of BaM particles. In the present work efficient and inexpensive chemical processes (co-precipitation, dry mixing and wet mixing) are presented that produces highly oriented bulk compacts made of Barium hexaferrites (BaM) particles. Hysteresis loops that display very competitive squarenesses between 0.87 and 0.90 (normalized remanent magnetization) and coercivity as high as 303 kA/m are obtained. The sensitivity to demagnetizing effects is therfore reduced. These properties make these BaM bulk ferrite materials suitable for selfbiased applications at frequencies up to 55 GHz