期刊文献+
共找到58篇文章
< 1 2 3 >
每页显示 20 50 100
Total adenosine deaminase cases as an inflammatory biomarker of pleural effusion syndrome
1
作者 Bernardo Henrique Ferraz Maranhão Cyro Teixeira da Silva Junior +3 位作者 Jorge Luiz Barillo Joeber Bernardo Soares Souza Patricia Siqueira Silva Roberto Stirbulov 《World Journal of Clinical Cases》 2025年第19期14-23,共10页
BACKGROUND Although inflammatory diseases commonly affect the pleura and pleural space,their mechanisms of action remain unclear.The presence of several mediators emphasizes the concept of pleural inflammation.Adenosi... BACKGROUND Although inflammatory diseases commonly affect the pleura and pleural space,their mechanisms of action remain unclear.The presence of several mediators emphasizes the concept of pleural inflammation.Adenosine deaminase(ADA)is an inflammatory mediator detected at increased levels in the pleural fluid.AIM To determine the role of total pleural ADA(P-ADA)levels in the diagnosis of pleural inflammatory diseases.METHODS 157 patients with inflammatory pleural effusion(exudates,n=124,79%)and noninflammatory pleural effusion(transudates,n=33,21%)were included in this observational retrospective cohort study.The P-ADA assay was tested using a kinetic technique.The performance of the model was evaluated using the area under the receiver operating characteristic(ROC)curve(AUC).The ideal cutoff value for P-ADA in pleural inflammation was determined using the Youden index in the ROC curve.RESULTS The transudates included congestive heart failure(n=26),cirrhosis of the liver with ascites(n=3),chronic renal failure(n=3),and low total protein levels(n=1).The exudate cases included tuberculosis(n=44),adenocarcinoma(n=37),simple parapneumonic effusions(n=15),complicated parapneumonic effusions/empyema(n=8),lymphoma(n=7),and other diseases(n=13).The optimal cutoff value of P-ADA was≥9.00 U/L.The diagnostic parameters as sensitivity,specificity,positive and negative predictive values,positive and negative likelihood values,odds ratio,and accuracy were 77.69(95%CI:69.22-84.75);68.75(95%CI:49.99-83.88);90.38 and 44.90(95%CI:83.03-95.29;30.67-59.77);2.48 and 0.32(95%CI:2.21-11.2;0.27-0.51);7.65(95%CI:0.78-18.34),and 75.82(95%CI:68.24-82.37),respectively(χ^(2)=29.51,P=0.00001).An AUC value of 0.8107(95%CI:0.7174-0.8754;P=0.0000)was clinically useful.The Hosmer-Lemeshow test showed excellent discrimination.CONCLUSION P-ADA biomarker has high diagnostic performance for pleural inflammatory exudates. 展开更多
关键词 Pleural effusion BIOMARKER Adenosine deaminase INFLAMMATION transudate EXUDATE
暂未订购
Community Knowledge about Bleeding Control in Jazan, KSA: Is There a Need for First Aid Educational Programs
2
作者 Md Mazharul Hoque Hamoud Yahya Alsuriha +10 位作者 Mohamed E. Moukhyer Bahja Siddig Mohamed Mubarak Almaki Amna Moukhyer Fawaz Yahya Masswadi Mofareh Salman Harubi Elias Yosef Modabish Talal Omar Khasawi Yaser Mohammed Hantool Mohammed Awaji Mohammed Madkhali Aziza Mukhayer 《Journal of Biosciences and Medicines》 2024年第6期64-84,共21页
The current study aimed to evaluate the first aid knowledge and general awareness of bleeding control, and their relations with different variables among the population of Jazan City, Saudi Arabia, in 2023. A cross-se... The current study aimed to evaluate the first aid knowledge and general awareness of bleeding control, and their relations with different variables among the population of Jazan City, Saudi Arabia, in 2023. A cross-sectional study was conducted in Jazan City, Saudi Arabia between April 2023 and May 2023. Participants, >13 years old, living in Jazan City, were self-enrolled. Data collection was carried out by distributing a self-reported online survey questionnaire via email and social media apps. A validated, pretested online self-report questionnaire was used for data collection, with data analysis performed using (MS) Excel 2022 and SPSS version 26. A Chi-square test was used to determine the association of sociodemographic variables and Bleeding Control (BC) knowledge with, significance set at p < 0.05. A total of 250 participants completed the questionnaire, predominantly aged between 16 - 25 years, with 152 (60.8%) being male, and about 90% being Saudi citizens. Only 53 (21.2%) participated in previous first aid training concentrating on bleeding control. Only 76 (30.4%) of participants had good knowledge, while 131 (52.4%) exhibited positive attitude towards BC first aid. There were no statistically significant associations between BC knowledge and age, gender, occupation, nationality, and education. However, a significant association was observed between previous BC training and knowledge (Chi-test = 40.373, d.f = 1, p = 0.000) at p < 0.05. Conclusion: The prevalence of poor knowledge of bleeding control among community members in Jazan City was high. The findings of this study should be carefully considered by various healthcare organizations to implement educational first-aid programs and activities aimed at enhancing community awareness and knowledge of bleeding control. 展开更多
关键词 INJURY Uncontrolled Bleeding First Aid Knowledge ATTITUDE Jazan City
在线阅读 下载PDF
中国宜昌王家湾晚奥陶世五峰组几丁虫的初步研究 被引量:9
3
作者 Thijs R.A.VANDENBROUCKE 陈旭 Jacques VERNIERS 《古生物学报》 CAS CSCD 北大核心 2005年第2期203-208,共6页
中国宜昌王家湾北剖面已被提名为奥陶系赫南特阶的全球候选层型剖面。为此著者分析了王家湾地区,特别是王家湾南和王家湾小河边奥陶—志留系间相关地层共20个层位的几丁虫样品。初步研究的结果表明,王家湾赫南特阶之下,相当奥陶纪第6个... 中国宜昌王家湾北剖面已被提名为奥陶系赫南特阶的全球候选层型剖面。为此著者分析了王家湾地区,特别是王家湾南和王家湾小河边奥陶—志留系间相关地层共20个层位的几丁虫样品。初步研究的结果表明,王家湾赫南特阶之下,相当奥陶纪第6个阶顶部,即五峰组中部产出的几丁虫与美国内华达中部Vnini河谷以及加拿大极区Cape Mannig的Ordochitina nevadensis 和Nevadachitina vininica 几丁虫带的分子可以进行对比。 展开更多
关键词 几丁虫 五峰组 晚奥陶世 宜昌 中国 层型剖面 CAPE 奥陶系 志留系 奥陶纪 加拿大 内华达 中部
在线阅读 下载PDF
Ductility demands on buckling-restrained braced frames under earthquake loading 被引量:13
4
作者 Larry A.Fahnestock Richard Sause +1 位作者 James M.Ricles Le-Wu Lu 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2003年第2期255-268,共14页
Accurate estimates of ductility demands on buckling-restrained braced frames(BRBFs)are crucial to performance-based design of BRBFs.An analytical study on the seismic behavior of BRBFs has been conducted at the ATLSS ... Accurate estimates of ductility demands on buckling-restrained braced frames(BRBFs)are crucial to performance-based design of BRBFs.An analytical study on the seismic behavior of BRBFs has been conducted at the ATLSS Center,Lehigh University to prepare for an upcoming experimental program.The analysis program DRAIN-2DX was used to model a one-bay,four-story prototype BRBF including material and geometric nonlinearities.The buckling- restrained brace(BRB)model incorporates both isotropic and kinematic hardening.Nonlinear static pushover and time- history analyses were performed on the prototype BRBF.Performance objectives for the BRBs were defined and used to evaluate the time-history analysis results.Particular emphasis was placed on global ductility demands and ductility demands on the BRBs.These demands were compared with anticipated ductility capacities.The analysis results,along with results from similar previous studies,are used to evaluate the BRBF design provisions that have been recommended for codification in the United States.The results show that BRB maximum ductility demands can be as high as 20 to 25.These demands significantly exceed those anticipated by the BRBF recommended provisions.Results from the static pushover and time- history analyses are used to demonstrate why the ductility demands exceed those anticipated by the recommended provisions. The BRB qualification testing protocol contained in the BRBF recommended provisions is shown to be inadequate because it requires only a maximum ductility demand of at most 7.5.Modifications to the testing protocol are recommended. 展开更多
关键词 BUILDINGS buckling-restrained braced frames buckling-restrained braces structural response seismic response ductility demand seismic codes and standards
在线阅读 下载PDF
Helicobacter pylori infection and expression of DNA mismatch repair proteins 被引量:5
5
作者 Vahid Mirzaee Mahsa Molaei +1 位作者 Hamid Mohaghegh Shalmani Mohammad Reza Zali 《World Journal of Gastroenterology》 SCIE CAS CSCD 2008年第43期6717-6721,共5页
AIM: TO determine the expression of DNA (MMR) proteins, including hMLH1 and hMSH2, in gastric epithelial cells in the patients with or without Helicobacter pylori (H pylori)-infected gastritis. METHODS: Fifty Hp... AIM: TO determine the expression of DNA (MMR) proteins, including hMLH1 and hMSH2, in gastric epithelial cells in the patients with or without Helicobacter pylori (H pylori)-infected gastritis. METHODS: Fifty Hpylori-positive patients and 50 H pylori-negative patients were enrolled in the study. During endoscopy of patients with non-ulcer dyspepsia, two antral and two corpus biopsies were taken for histological examination (Giemsa stain) and for immunohistochemical staining of hMLH1 and hMSH2. RESULTS: The percentage of epithelial cell nuclei that demonstrated positivity for hMLH1 staining was 84.14 ± 7.32% in Hpylori-negative patients, while it was 73.34 ±10.10% in Hpylori-positive patients (P 〈 0.0001). No significant difference was seen between the two groups regarding the percentage of epithelial cell nuclei that demonstrated positivity for hMSH2 staining (81.16±8.32% in H pylori-negative versus 78.24 ± 8.71% in Hpylori-positive patients; P = 0.09). CONCLUSION: This study indicates that Hpylori might promote development of gastric carcinoma at least in part through its ability to affect the DNA MMR system 展开更多
关键词 Helicobacter pylori DNA mismatch repair hMLH1 hMSH2
暂未订购
Effect of acupressure on procedural pain before heel lancing in neonates 被引量:2
6
作者 Tanju Oğul Fatma Yilmaz Kurt 《Journal of Traditional Chinese Medicine》 SCIE CAS CSCD 2021年第2期331-337,共7页
OBJECTIVE:To investigate the effect of acupressure applied to UB60 and K3 acupuncture points in order to relieve the procedural pain caused by heel lancing blood sampling process in the term newborns.METHODS:The data ... OBJECTIVE:To investigate the effect of acupressure applied to UB60 and K3 acupuncture points in order to relieve the procedural pain caused by heel lancing blood sampling process in the term newborns.METHODS:The data were collected by using the Information Form and the Neonatal Infant Pain Scale.Acupressure applied for 3 min before heel lancing blood sampling in the newborns in the experimental group(n=31).No intervention was applied to newborns in the control group(n=32).RESULTS:A significant difference was found between mean scores of the newborns in the control and acupressure group in favor of the acupressure group in terms of heart rate during and after the procedure,oxygen saturation before,during and after the procedure,duration of crying during and after the procedure(P<0.05).It was found that there was a significant difference between groups in terms of Neonatal Infant Pain Scale mean scores during(P=0.001)and after the procedure(P<0.05),and the difference was found to be in favor of the acupressure group.CONCLUSION:As a result,acupressure was found to be an effective method in relieving pain caused by heel lancing blood sampling in newborns. 展开更多
关键词 ACUPRESSURE Pain procedural Infant newborn Heel lancing blood sampling
原文传递
Remote structural health monitoring with serially multiplexed fiber optic acoustic emission sensors 被引量:2
7
作者 陈仲裕 梁玉进 Farhad Ansari 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2003年第1期141-146,共6页
Development and testing of a serially multiplexed fiber optic sensor system is described.The sensor differs from conventional fiber optic acoustic systems,as it is capable of sensing AE emissions at several points alo... Development and testing of a serially multiplexed fiber optic sensor system is described.The sensor differs from conventional fiber optic acoustic systems,as it is capable of sensing AE emissions at several points along the length of a single fiber.Multiplexing provides for single channel detection of cracks and their locations in large structural systems. An algorithm was developed for signal recognition and tagging of the AE waveforms for detection of' crack locations,Labora- tory experiments on plain concrete beams and post-tensioned FRP tendons were pcrlormed to evaluate the crack detection capability of the sensor system.The acoustic emission sensor was able to detect initiation,growth and location of the cracks in concrete as well as in the FRP tendons.The AE system is potentially suitable lot applications involving health monitoring of structures following an earthquake. 展开更多
关键词 acoustic emission crack detection concrete EARTHQUAKE fiber optic sensors FRP tendon MULTIPLEXING post seismic structural health monitoring
在线阅读 下载PDF
Earthquake risk assessment for Istanbul metropolitan area 被引量:3
8
作者 M.Erdik N.Aydinoglu +8 位作者 Y.Fahjan K.Sesetyan M.Demircioglu B.Siyahi E.Durukal C.Ozbey Y.Biro H.Akman O.Yuzugullu 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2003年第1期1-24,共24页
The impact of earthquakes in urban centers prone to disastrous earthquakes necessitates the analysis of associ- ated risk for rational formulation of contingency plans and mitigation strategies.In urban centers,the se... The impact of earthquakes in urban centers prone to disastrous earthquakes necessitates the analysis of associ- ated risk for rational formulation of contingency plans and mitigation strategies.In urban centers,the seismic risk is best quantified and portrayed through the preparation of'Earthquake Damage and Loss Scenarios.'The components of such scenarios are the assessment of the hazard,inventories and the vulnerabilities of elements at risk.For the development of the earthquake risk scenario in Istanbul,two independent approaches,one based on intensities and the second on spectral displacements,are utilized.This paper will present the important features of a comprehensive study,highlight the method- ology,discuss the results and provide insights to future developments. 展开更多
关键词 earthquake risk assessment metropolitan area INTENSITY spectral displacement earthquake damage loss scenario
在线阅读 下载PDF
Disbond detection with piezoelectric wafer active sensors in RC structures strengthened with FRP composite overlays 被引量:2
9
作者 Victor Giurgiutiu Kent Harries +2 位作者 Michael Petrou Joel Bost Josh B.Quattlebaum 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2003年第2期213-223,共11页
The capability of embedded piezoelectric wafer active sensors(PWAS)to perform in-situ nondestructive evaluation(NDE)for structural health monitoring(SHM)of reinforced concrete(RC)structures strengthened with fiber rei... The capability of embedded piezoelectric wafer active sensors(PWAS)to perform in-situ nondestructive evaluation(NDE)for structural health monitoring(SHM)of reinforced concrete(RC)structures strengthened with fiber reinforced polymer(FRP)composite overlays is explored.First,the disbond detection method were developed on coupon specimens consisting of concrete blocks covered with an FRP composite layer.It was found that the presence of a disbond crack drastically changes the electromecfianical(E/M)impedance spectrum lneasurcd at the PWAS terlninals.The spectral changes depend on the distance between the PWAS and the crack tip.Second,large scale experiments were conducted on a RC beam strengthened with carbon fiber reinforced polymer(CFRP)composite overlay.The beam was subject to an accelerated fatigue load regime in a three-point bending configuration up to a total of 807,415 cycles.During these fatigue tests,the CFRP overlay experienced disbonding beginning at about 500,000 cycles.The PWAS were able to detect the disbonding before it could be reliably seen by visual inspection.Good correlation between the PWAS readings and the position and extent of disbond damage was observed.These preliminary results demonstrate the potential of PWAS technology for SHM of RC structures strengthened with FRP composite overlays. 展开更多
关键词 FRP composite overlays composite strengthening and rehabilitation structural health monitoring piezoelectric wafer active sensors E/M impedance aging infrastructure disbond damage PWAS
在线阅读 下载PDF
A three-dimensional nonlinear reduced-order predictive joint model 被引量:3
10
作者 宋亚新 Hartwigsen +1 位作者 LawrenceA.Bergman AlexanderF.Vakakis 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2003年第1期59-74,共16页
Mechanical joints can have significant effects on the dynamics of assembled structures.However,the lack of efficacious predictive dynamic models tot joints hinders accurate prediction of their dynamic behavior.The goa... Mechanical joints can have significant effects on the dynamics of assembled structures.However,the lack of efficacious predictive dynamic models tot joints hinders accurate prediction of their dynamic behavior.The goal of our work is to develop physics-based,reduced-order,finite element models that are capable of replicating the effects of joints on vi- brating structures.The authors recently developed the so-called two-dimensional adjusted lwan beam element(2-D AIBE) to simulate the hysteretic behavior of bolted joints in 2-D beam structures.In this paper,2-D AIBE is extended to three-di- mensional cases by formulating a three-dimensional adjusted lwan beam element(3-D AIBE).hupulsive loading experi- ments are applied to a jointed frame structure and a beam structure containing the same joint.The frame is subjected to ex- citation out of plane so that the joint is under rotation and single axis bending.By assuming that the rotation in the joint is linear elastic,the parameters of the joint associated with bending in the flame are identified from acceleration responses of the jointed beam structure,using a multi-layer teed-torward neural network(MLFF).Numerieal simulation is then per- formed on the frame structure using the identified parameters.The good agreement between the simulated and experimental impulsive acceleration responses of the frame structure validates the efficacy of the presented 3-D AIBE,and indicates that the model can potentially be applied to more complex structural systems with joint parameters identified from a relatively simple structure. 展开更多
关键词 boiled joints adjusted Iwan beam element (AIBE) nonlinear dynamic analysis parameter identification multi-layer feed-forward neural networks (MLFF)
在线阅读 下载PDF
Vitamin D levels in subjects with or without chronic kidney disease among Veterans with diabetes in North East United States 被引量:1
11
作者 Subhashini Yaturu Barbara Youngberg Sonya Zdunek 《World Journal of Diabetes》 SCIE CAS 2017年第7期346-350,共5页
AIM To evaluate the prevalence of vitamin D deficiency and its relation to diabetes and kidney disease in Veterans residing in the North East United States(VISN 2).METHODS In this retrospective study,we used data from... AIM To evaluate the prevalence of vitamin D deficiency and its relation to diabetes and kidney disease in Veterans residing in the North East United States(VISN 2).METHODS In this retrospective study,we used data from the computerized patient record system at Stratton Veterans Administration Medical Center at Albany,NY(VHA)for those patients who had 25-hydroxyvitamin D levels and 1,25(OH)vitamin D levels measured between 2007 and 2010.We collected demographic information including age,sex,body mass index and race;clinical data including diabetes,hypertension and CAD;and laboratory data including calcium,creatinine and parathyroid hormone(PTH)(intact).Vitamin D deficiency is defined as a serum 25-hydroxyvitamin D level of less than 20 ng/mL(50 nmol/L),and insufficiency is defined as a serum 25-hydroxyvitamin D level of 20 to 30 ng/mL(50 to 75 nmol/L).RESULTS Data was available for approximately 68000 subjects.We identified 64144 subjects for analysis after exclusion of duplicates.Among them,27098 had diabetes.Themean age of subjects with diabetes was 68±11 with a mean body mass index(BMI)of 32±7 and duration of diabetes of 5.6±3.2 years.The mean 25(OH)vitamin D level among subjects with diabetes was 27±11.6.There was no significant difference in 25(OH)vitamin D levels between subjects with diabetes and glomerular filtration rate(e-GFR)<60 compared to those with e-GFR≥60.As expected,subjects with e-GFR<60 had significantly lower 1,25(OH)vitamin D levels and significantly elevated PTH-intact.Of the 64144 subjects,580 had end-stage renal disease.Of those,407 had diabetes and 173 did not.Vitamin D levels in both groups were in the insufficiency range and there was no significant difference irrespective of presence or absence of diabetes.Subjects with vitamin D levels less than 20 ng/mL had a higher BMI and elevated PTH,and higher HbA 1C levels compared to those with vitamin D levels more than 20 ng/mL.CONCLUSION We conclude that we need to keep a close eye on vitamin D levels in subjects with mild chronic kidney disease as well as those with moderate control of diabetes. 展开更多
关键词 Vitamin D Type 2 diabetes MEN Chronic kidney disease End stage renal disease
暂未订购
Altered heart rate variability and pulse-wave velocity after spinal cord injury 被引量:1
12
作者 Hsi-Kai Tsou Kuan-Chung Shih +2 位作者 Yueh-Chiang Lin Yi-Ming Li Hsiao-Yu Chen 《World Journal of Clinical Cases》 SCIE 2022年第27期9680-9692,共13页
BACKGROUND Heart rate variability(HRV) and pulse-wave velocity(PWV),indicators of cardiac function,are altered in patients with spinal cord injury(SCI),suggesting that autonomic cardiac function and arterial stiffness... BACKGROUND Heart rate variability(HRV) and pulse-wave velocity(PWV),indicators of cardiac function,are altered in patients with spinal cord injury(SCI),suggesting that autonomic cardiac function and arterial stiffness may underlie the high risk of cardiovascular complications in these patients.No study has simultaneously investigated HRV and PWV in the same patients.AIM To evaluate cardiovascular complications in SCI patients by comparing HRV and PWV between patients with and without SCI.METHODS In this cross-sectional pilot study,patients with(n = 60) and without SCI(n = 60) were recruited from December 7,2019 to January 21,2020.Each participant received a five-minute assessment of HRV and the cardiovascular system using the Medicore HRV Analyzer SA-3000 P.Differences in HRV and PWV parameters between participants with and without SCI were statistically examined.RESULTS We observed a significant difference between participants with and without SCI with respect to the standard deviation of all normal-to-normal intervals,square root of the mean sum of squared successive risk ratio interval differences,physical stress index,total power,very-low frequency,low frequency,high frequency,and arterial elasticity.CONCLUSION Patients with SCI have weaker sympathetic and parasympathetic activity as well as lower arterial elasticity compared to those without,suggesting that SCI may increase cardiac function loading. 展开更多
关键词 Acceleration plethysmography Cardiac function Heart rate variability Pulse wave velocity Spinal cord injury
暂未订购
A study on the seismic behavior of a retrofitted building based on nonlinear static and dynamic analyses 被引量:1
13
作者 Esra Mete Güneyisi Gülay Altay 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2005年第1期173-180,共8页
This study describes the seismic performance of an existing five storey reinforced concrete building which represents the typical properties of low-rise non-ductile buildings in Turkey. The effectiveness of shear wall... This study describes the seismic performance of an existing five storey reinforced concrete building which represents the typical properties of low-rise non-ductile buildings in Turkey. The effectiveness of shear walls and the steel bracings in retrofitting the building was examined through nonlinear static and dynamic analyses. By using the nonlinear static analysis, retrofitted buildings seismic performances under lateral seismic load were compared with each other. Moreover, the performance points and response levels of the existing and retrofitting cases were determined by way of the capacity-spectrum method described in ATC-40 (1996). For the nonlinear dynamic analysis the records were selected to represent wide ranges of duration and frequency content. Considering the change in the stiffness and the energy dissipation capacities, the performance of the existing and retrofitted buildings were evaluated in terms of story drifts and damage states. It was found that each earthquake record exhibited its own peculiarities, dictated by frequency content, duration, sequence of peaks and their amplitude. The seismic performance of retrofitted buildings resulted in lower displacements and higher energy dissipation capacity depending mainly on the properties of the ground motions and the retrofitting strategies. Moreover, severe structural damage (irreparable or collapse) was observed for the existing building. However, buildings with retrofit alternatives exhibited lower damage levels changing from no damage to irreparable damage states. 展开更多
关键词 nonlinear static analysis nonlinear time history analysis performance level retrofitting shear wall steel bracing
在线阅读 下载PDF
Reduced combustion time model for methane in gas turbine flow fields 被引量:1
14
作者 Mouna Lamnaouer Robert C. Ryder +1 位作者 Andreja Brankovic Eric L. Petersen 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2009年第2期145-155,共11页
Computational fluid dynamics (CFD) modeling of the complex processes that occur within the burner of a gas turbine engine has become a critical step in the design process. However, due to computer limitations, it is... Computational fluid dynamics (CFD) modeling of the complex processes that occur within the burner of a gas turbine engine has become a critical step in the design process. However, due to computer limitations, it is very difficult to completely couple the fluid mechanics solver with the full combustion chemistry. Therefore, simplified chemistry models are required, and the topic of this research was to provide reduced chemistry models for CH4/O2 gas turbine flow fields to be integrated into CFD codes for the simulation of flow fields of natural gas-fueled burners. The reduction procedure for the CH4/O2 model utilized a response modeling technique wherein the full mechanism was solved over a range of temperatures, pressures, and mixture ratios to establish the response of a particular variable, namely the chemical reaction time. The conditions covered were between 1000 and 2500 K for temperature, 0.1 and 2 for equivalence ratio in air, and 0.1 and 50 atm for pressure. The kinetic time models in the form of ignition time correlations are given in Arrhenius-type formulas as functions of equivalence ratio, temperature, and pressure; or fuel-to-air ratio, temperature, and pressure. A single ignition time model was obtained for the entire range of conditions, and separate models for the low-temperature and high-temperature regions as well as for fuel-lean and rich cases were also derived. Predictions using the reduced model were verified using results from the full mechanism and empirical correlations from experiments. The models are intended for (but not limited to) use in CFD codes for flow field simulations of gas turbine combustors in which initial conditions and degree of mixedness of the fuel and air are key factors in achieving stable and robust combustion processes and acceptable emission levels. The chemical time model was utilized successfully in CFD simulations of a generic gas turbine combustor with four different cases with various levels of fuel-air premixing. 展开更多
关键词 CH4 ignition time correlations reduced kinetic model
在线阅读 下载PDF
Efficient Orbit Propagation of Orbital Elements Using Modified Chebyshev Picard Iteration Method
15
作者 J.L.Read A.Bani Younes J.L.Junkins 《Computer Modeling in Engineering & Sciences》 SCIE EI 2016年第1期65-81,共17页
This paper focuses on propagating perturbed two-body motion using orbital elements combined with a novel integration technique.While previous studies show that Modified Chebyshev Picard Iteration(MCPI)is a powerful to... This paper focuses on propagating perturbed two-body motion using orbital elements combined with a novel integration technique.While previous studies show that Modified Chebyshev Picard Iteration(MCPI)is a powerful tool used to propagate position and velocity,the present results show that using orbital elements to propagate the state vector reduces the number of MCPI iterations and nodes required,which is especially useful for reducing the computation time when including computationally-intensive calculations such as Spherical Harmonic gravity,and it also converges for>5.5x as many revolutions using a single segment when compared with cartesian propagation.Results for the Classical Orbital Elements and the Modified Equinoctial Orbital Elements(the latter provides singularity-free solutions)show that state propagation using these variables is inherently well-suited to the propagation method chosen.Additional benefits are achieved using a segmentation scheme,while future expansion to the two-point boundary value problem is expected to increase the domain of convergence compared with the cartesian case.MCPI is an iterative numerical method used to solve linear and nonlinear,ordinary differential equations(ODEs).It is a fusion of orthogonal Chebyshev function approximation with Picard iteration that approximates a long-arc trajectory at every iteration.Previous studies have shown that it outperforms the state of the practice numerical integrators of ODEs in a serial computing environment;since MCPI is inherently massively parallelizable,this capability is expected to increase the computational efficiency of the method presented. 展开更多
关键词 PROPAGATION Integration Orbital Mechanics Classical Elements MODIFIED Equinoctial CHEBYSHEV PICARD Iteration MCPI Polynomials Initial Value Problem IVP.
在线阅读 下载PDF
意大利辅助用具免费供给残疾人体系(英文)
16
作者 Maria Teresa Agati Alessandro Giustini Adelmo Gian Martino Mazzocchi 《中国康复理论与实践》 CSCD 2011年第10期925-930,共6页
Aids are only one of the instruments with which the disabled person can often reach a good level of autonomy,he can improve his conditions of life and prevent the aggravating of his situation. Aids serve also to facil... Aids are only one of the instruments with which the disabled person can often reach a good level of autonomy,he can improve his conditions of life and prevent the aggravating of his situation. Aids serve also to facilitate care on the part of the family. The rights confirmed by Law 104 can also be achieved through the use of aids. The Italian state has planned a system of care with regards to aids so that some of them can be purchased with different tax concessions but essential aids,those necessary for the reaching of autonomy goals and prevention defined by an individual rehabilitative project,are supplied free of charge. In Italy essential aids are part therefore of a rehabilitation plan that is identified for each person with disabilities by a team made up of different professionals. 展开更多
关键词 assistive technology Italian system INCENTIVES free supply improvement of ISO classification rehabilitation project individualise and personalize
暂未订购
Active control of highway bridges subject to a variety of earthquake loads
17
作者 Ryan Mitchell Young-Jin Cha +1 位作者 Yeesock Kim Aniket Anil Mahajan 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2015年第2期253-263,共11页
In this paper, a wavelet-fi ltered genetic-neuro-fuzzy(WGNF) control system design framework for response control of a highway bridge under various earthquake loads is discussed. The WGNF controller is developed by co... In this paper, a wavelet-fi ltered genetic-neuro-fuzzy(WGNF) control system design framework for response control of a highway bridge under various earthquake loads is discussed. The WGNF controller is developed by combining fuzzy logic, discrete wavelet transform, genetic algorithms, and neural networks for use as a control algorithm. To evaluate the performance of the WGNF algorithm, it is tested on a highway bridge equipped with hydraulic actuators. It controls the actuators installed on the abutments of the highway bridge structure. Various earthquakes used as input signals include an artifi cial earthquake, the El-Centro, Kobe, North Palm Springs, Turkey Bolu, Chi-Chi, and Northridge earthquakes. It is proved that the WGNF control system is effective in mitigating the vibration of the highway bridge under a variety of seismic excitation. 展开更多
关键词 structural control wavelet transform genetic algor
在线阅读 下载PDF
意大利辅助用具免费供给残疾人体系:未来发展(英文)
18
作者 Maria Teresa Agati Alessandro Giustini 《中国康复理论与实践》 CSCD 2011年第10期931-934,共4页
The Italian care situation with regards to prostheses and aids is satisfying. The norm which establishes the ways in which aids can be supplied to disabled people goes back to 1999 and,even though it is based on corre... The Italian care situation with regards to prostheses and aids is satisfying. The norm which establishes the ways in which aids can be supplied to disabled people goes back to 1999 and,even though it is based on correct principles and even though it has produced positive effects in the improvement of the life of disabled people,it must be updated in the light of the more recent technological and scientific innovations and of the new information instruments such as the diffusion of information and communication systems. 展开更多
关键词 Essential Levels of Health Assistance list of indispensable devices CUSTOMIZATION standard devices multidisciplinary team aid registration
暂未订购
帮助小的和不那么小的企业提高他们的三重底线成绩
19
作者 Justus von Geibler Michael Kuhndt 李弗兰 《产业与环境》 CAS 2003年第3期63-66,共4页
要维持其市场地位,中小企业就必须提高他们的效率.然而,他们往往因为缺少时间、金钱和信息而难以对他们自己的活动、制定目标以及因此不断提高产品和服务(经济上、社会上和环境上)做出正确估价.现有的复杂的国际环境管理方案,对于中小... 要维持其市场地位,中小企业就必须提高他们的效率.然而,他们往往因为缺少时间、金钱和信息而难以对他们自己的活动、制定目标以及因此不断提高产品和服务(经济上、社会上和环境上)做出正确估价.现有的复杂的国际环境管理方案,对于中小企业常常不适用.不同级别信息“门童”间的合作,对于提高中小企业的环境与社会健康生产方式意识、教给他们日常业务中一体化关注环境与社会的方法、确立经济地位以及奖励这些努力,都是十分必要的. 展开更多
关键词 中小企业 经济 环境 社会 生产效率 经济地位 可持续发展
在线阅读 下载PDF
China-Japan-ROK Relations in Post-Beijing Olympics—Summary of the Sino-Japan-ROK Trilateral Symposium
20
作者 Han Fang 《Contemporary International Relations》 2008年第6期92-98,共7页
The trilateral seminar of'China-Japan-ROK Relations in PostBeijing Olympics'—organized by China Institutes of Contemporary International Relations(CICIR),the Asahi Shimbun Asia Network(AAN) of Japan and the H... The trilateral seminar of'China-Japan-ROK Relations in PostBeijing Olympics'—organized by China Institutes of Contemporary International Relations(CICIR),the Asahi Shimbun Asia Network(AAN) of Japan and the Hwajeong Peace Foundation of Northeast Asia Daily(the Dibg-A Ilbo)in South Korea—opened in Beijing on October 11th,2008. 展开更多
关键词 中国 日本 韩国 国际关系
在线阅读 下载PDF
上一页 1 2 3 下一页 到第
使用帮助 返回顶部