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A work-hardening and softening constitutive model for sand:modified plastic strain energy approach

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Acta mechanica Sinica 2005年第1期21卷 76-86页

作者： FanglePeng m.S.A.Siddiquee ShaomingLiao DepartmentofGeotechnicalEngineering TongiiUniversityShanghai200092China DepartmentofcivilEngineering TheUniversityofTokyoTokyo1138656Japan DepartmentofGeotechnicalEngineering TongiiUniversityShanghai200092China//DepartmentofCivilEngineeringTheUniversityofTokyoTokyo1138656Japan

The paper describes an energy-based constitutive model for sand, which is modified based on the modified plastic strain energy approach, represented by a unique relationship between the modified plastic strain energy and a stress parameter, independent of stress history. The modified plastic strain energy approach was developed based on results from a series of drained plastic strain compression tests along various stress paths on saturated dense Toyoura sand with accurate stress and strain measurements. The proposed model is coupled with an isotropically work-hardening and softening, non-associtated, elasto-plastic material description. The constitutive model concerns the inherent and stress system-induced cross-anisotropic elastic deformation properties of sand. It is capable of simulating the deformation characteristics of stress history and stress path, the effects of pressure level, anisotropic strength and void ratio, and the strain localization.

关键词： Sand Energy-based Hardening and softening Elasto-plastic model Stress-strain relation

Interactions among micronutrient Deficiencies and Undernutrition in the Philippines

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Biomedical and Environmental Sciences 1996年第2期9卷 348-357页

作者： R. F. FLORENTINO c. c. TANcHOcO m. P. RODRIGUEZ A. J. cRUZ AND W. L. mOLANO(Food and Nutrition Research Insititute-Department of Science and Technology Science compound Bicutan, Tagig, metro manila, Philippines) Food and Nutrition Research Insititute-Department of Science and Technology Science Compound Bicutan Tagig Manila Philippines

Data gathered from the 1987 National Nutrition Survey in the Philippines provided the opportunity to study the interactions among micronutrient deficiencies and undernutrition in different age groups as basis for program targeting. A randomly selected set of 50% of the households (3,200) covered by the national survey served as source of subjects. Results showed that there was a greater proportion of anemia among the undernourished (as judged by weight for age in children and weight for height in adults) (66.0%)than among the adequately nourished (54.6%) (P cesin the proportion of serum vitamin A deficiency and of goiter among the undernourished compared to the adequately nourished were not significant. Also not significant were the observed higher prevalence of anemia among subjects with acceptable serum vitamin A levels for both adequately nourished and undernourished, and the higher prevalence of vitamin A deficiency among the non-anemics. Again there were no significant differences in the prevalence of anemia among goitrous and non-goitrous subjects, as well as the prevalence of goiter among anemic and non-anemic subjects. Neither were there significant differences in the prevalence of vitamin A deficiency among goitrous and non-goitrous subjects, but there were significant differences in the prevalence of goiter among vitamin A deficient and non-vitamin A defjcient subjects among the 7-14 years old and among pregnant and lactating *** study concludes that at the national level, there is apparently an interaction between anemia and protein-energy undernutrition and possibly also between goiter and vitamin A deficiency in the high-risk age groups, but between anemia on the one hand and goiter and vitamin A deficiency in the other, perhaps because of clustering in the latter conditions not found in anemia and general undernutrition. These findings may be useful in targeting communities with high prevalence of micronutri

关键词： World Organization WHO Interactions among micronutrient Deficiencies and Undernutrition in the Philippines

A comparative review of artificial muscles for microsystem applications

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microsystems & Nanoengineering 2021年第6期7卷 25-43页

作者： mayue Shi Eric m.Yeatman Department of Electrical and Electronic Engineering Imperial College LondonExhibition RoadLondon SW72AZUK

Artificial muscles are capable of generating actuation in microsystems with outstanding *** years have witnessed a growing academic interest in artificial muscles and their application in many areas,such as soft robotics and biomedical *** paper aims to provide a comparative review of recent advances in artificial muscle based on various operating *** advantages and limitations of each operating mechanism are analyzed and *** to the unique application requirements and electrical and mechanical properties of the muscle types,we suggest suitable artificial muscle mechanisms for specific microsystem ***,we discuss potential strategies for energy delivery,conversion,and storage to promote the energy autonomy of microrobotic systems at a system level.

关键词： artificial generating limitations

Target Delineation in High-grade Glioma Do cTV margins make a Difference? ESTRO AcROP versus RTOG Guidelines a comparative Dosimetric Study

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Advances in modern Oncology Research 2018年第6期4卷 32-36页

作者： Bindhu Joseph Vishal malavade Nisarga V m Vijay c R Ramesh c Lokesh Vishwanath Kidwai memorial Institute of Oncology Dr M H Marigowda roadBangalore560029KarnatakaIndia.

Background and purpose:There exist two major consensus guidelines for target delineation in glioblastoma(GBm).Namely the established radiation therapy oncology group(RTOG)and the recently redefined European society for radiation oncology(EORTc)-advisory committee on radiation oncology practice(AcROP),clinical studies evaluating the pattern of recurrence with relation to the cTV margins have as of date not evidenced statistically significant difference in relation to the two ***,considering the standardization of concurrent chemo-radiation with Temozolomide nearly 20%off patients can be expected to survive 2years or *** of life issues will play a higher role in defining the better *** the current study,we have dosimetrically compared these guidelines in both *** and methods:Thirty patients of GBm who had been planned for conformal radiotherapy during Jan 2017 to Feb 2019 were *** patient dataset contoured with ESTRO-AcROP guidelines to create PLAN A and RTOG guidelines to create PLAN *** plans were compared to evaluate the volumetric difference in terms of PTV and the relative proximity to critical normal ***:The median volume of brain irradiated to high doses(60Gy)was significantly greater in PLAN B,566cc vs 398 cc(Pms of encroachment of high dose PTV *** achieved significance for Brainstem(Pchiasma(Pcampus(Pme>400cc and with tumor in Parietal or Temporal regions wouldn’t benefit from PLAN ***:The use of target delineation based on a single step plan,excluding expanded edema(ESTRO-AcROP)could potentially reduce high dose target volumes and significantly spare brainstem,optic-chiasma,and *** with tumor volumecc and frontal lesions are most likely to benefit.

关键词： glioblastoma peritumoral edema contouring guidelines organs at risk

Statistical Analysis of Small Holder Farmer Financial Exclusion: case Study of migori county, Kenya

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Open Journal of Statistics 2022年第5期12卷 733-742页

作者： Susan A. Okeyo Galcano c. mulaku collins m. mwange Department of Geospatial and Space Technology University of Nairobi Nairobi Kenya

There are estimated to be approximately 600 million small scale farmers globally, and they produce most of the food consumed, especially in the developing countries. The farmers, however, are often unable to obtain optimal crop yields due to their exclusion from the financial systems in their countries, which deem them too high risk to lend to. This results in the farmers being unable to afford optimal inputs into their farms, hence depressing their yields and the level of food security. This study aimed to statistically determine whether the small scale farmers of migori county in Kenya are financially excluded or not, and to what extent. Data were collected from the farmers through a questionnaire survey, and subsequent statistical analysis has shown that indeed the small scale farmers of migori are financially excluded to a large extent. consideration of non-financial data in the farmers’ credit rating has been recommended as a way forward towards their financial inclusivity. This study provides scientific proof of smallholder farmer financial exclusion, which proof is generally difficult to find, especially in the developing countries.

关键词： Small Holder Farmer Financial Exclusion migori Kenya

Pre-sowing treatments for improved germination and growth of two rare native species of Bangladesh

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Journal of Forestry Research 2018年第5期29卷 1277-1282页

作者： m.A.Hossain K.S.Islam N.Rajasree m.K.Hossain m.S.Alam Institute of Forestry and Environmental Sciences University of Chittagong

Pre-sowing treatments are expected to increase seed *** evaluates response to pre-sowing treatments and the growth performance of two native and rare tree species,Garuga pinnata *** Vitex glabrata *** hard seed coats were treated by rubbing with sand paper,nail clipping,and immersion in water and acid（H_2SO_4）.Results indicate that *** showed a 90% germination rate and 30% germination energy when seed coats were nicked with a nail *** with sand paper was the best pre-sowing treatment for ***,resulting a 80% germination rate and 30% germination *** and *** seedlings from seeds soaked 24h in water resulted in maximum heights and collar *** were significantly higher（at p〈0.05） than those of other *** results indicate that scarification or nicking of seeds may have some negative impacts on seedling ***,it is difficult to recommend a pre-sowing treatment of seeds for achieving both maximum germination and good early seedling growth.

关键词： Germination Early seedling growth Height Native species Garuga pinnata Vitex glabrata

Electrical and dielectric properties of Na_(1/2)La_(1/2)cu_3Ti_4O_(12) ceramics prepared by high energy ball-milling and conventional sintering

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chinese Physics B 2016年第12期25卷 474-480页

作者： H mahfoz Kotb mohamad m Ahmad Department of Physics College of ScienceKing Faisal University Department of Physics Faculty of ScienceAssiut University

We report on the measurements of the electrical and dielectric properties of Na1/2La1/2cu3Ti4O12 （NLcTO） ce- ramics prepared by high energy ball-milling and conventional sintering without any calcination steps. The x-ray powder diffraction analysis shows that pure perovskite-like ccTO phase is obtained after sintering at 1025 ℃-1075 ℃. Higher sintering temperatures result in multi-phase ceramics due to thermal decomposition. Scanning electron microscope observations reveal that the grain size is in a range of - 3 μm-5 μm for these ceramics. Impedance spectroscopy measurements performed in a wide frequency range （1 Hz-10 mHz） and at various temperatures （120 K-470 K） are used to study the dielectric and electrical properties of NLcTO ceramics. A good compromise between high ε′ （5.7 ×10^3 and 4.1 × 10^3 at 1.1 kHz and 96 kHz, respectively） and low tan δ （0.161 and 0.126 at 1.1 kHz and 96 kHz, respectively） is obtained for the ceramic sintered at 1050 ℃. The observed high dielectric constant behavior is explained in terms of the internal barrier layer capacitance effect.

关键词： ceramics sintering dielectric loss and relaxation electrical

Finding vibrations of inclined cable structures by approximately solving governing equations for exterior matrix

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Applied mathematics and mechanics(English Edition) 2015年第11期36卷 1383-1402页

作者： W.PAULSEN m.mANNING Department of mathematics and Statistics Arkansas State University

In this paper, how to compute the eigenfrequencies of the structures composed of a series of inclined cables is shown. The physics of an inclined cable can be complicated, so solving the differential equations even approximately is difficult. However, rather than solving the system of 4 first-order equations governing the dynamics of each cable, the governing equations are instead converted to a set of equations that the exterior matrix satisfies. Therefore, the exterior matrix method （Emm） is used without solving the original governing equations. Even though this produces a system of 6 first-order equations, the simple asymptotic techniques to find the first three terms of the perturbative solution can be used. The solutions can then be assembled to produce a 6 x 6 exterior matrix for a cable section. The matrices for each cable in the structure are multiplied together, along with the exterior matrices for each joint. The roots of the product give us the eigenfrequencies of the system.

关键词： exterior matrix method (Emm) eigenfrequency inclined cable

Wave Energy Estimation by Using A Statistical Analysis and Wave Buoy Data near the Southern caspian Sea

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china Ocean Engineering 2015年第2期29卷 275-286页

作者： A.R.Zamani m.A.Badri Research Institute for Subsea Science and Technology Isfahan University of Technology

Statistical analysis was done on simultaneous wave and wind using data recorded by discus-shape wave buoy. The area is located in the southern caspian Sea near the Anzali Port. Recorded wave data were obtained through directional spectrum wave analysis. Recorded wind direction and wind speed were obtained through the related time series as well. For 12-month measurements（may 25 2007-2008）, statistical calculations were done to specify the value of nonlinear auto-correlation of wave and wind using the probability distribution function of wave characteristics and statistical analysis in various time periods. The paper also presents and analyzes the amount of wave energy for the area mentioned on the basis of available database. Analyses showed a suitable comparison between the amounts of wave energy in different seasons. As a result, the best period for the largest amount of wave energy was known. Results showed that in the research period, the mean wave and wind auto correlation were about three hours. Among the probability distribution functions, i.e Weibull, Normal, Lognormal and Rayleigh, ＂Weibull＂ had the best consistency with experimental distribution function shown in different diagrams for each season. Results also showed that the mean wave energy in the research period was about 49.88 k W/m and the maximum density of wave energy was found in February and march, 2010.

关键词： probability distribution function nonlinear auto-correlation wave energy statistical analysis Anzali Port