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Estimation of load and resistance factors using the third-moment method based on the 3P-lognormal distribution

Yan-Gang ZHAO, Zhao-Hui LU

《结构与土木工程前沿(英文)》 2011年 第5卷 第3期   页码 315-322 doi: 10.1007/s11709-011-0117-7

摘要: Load and resistance factors are generally obtained using the first order reliability method (FORM) in which the design point should be determined and derivative-based iterations used. In this article, the third-moment reliability index, based on the three-parameter lognormal (3P-lognormal) distribution, is investigated. A simple method based on the third-moment method for estimating load and resistance factors is then proposed, and a simple formula for the target mean resistance is also presented to avoid iterative computations. Unlike the currently used method, the proposed method can be used to determine load and resistance factors, even when the probability density functions (PDFs) of the basic random variables are not available. Moreover, the proposed method does not require the iterative computation of derivatives or any design points. Thus, the method provides a more convenient and effective way to estimate load and resistance factors in practical engineering applications. Numerical examples are presented to demonstrate the advantages of the proposed third moment method for determining load and resistance factors.

关键词: load and resistance factors     third-moment method     three-parameter lognormal (3P-lognormal) distribution     target mean resistance     simple formula    

A simple method for evaluating liquefaction potential from shear wave velocity

Lianyang ZHANG,

《结构与土木工程前沿(英文)》 2010年 第4卷 第2期   页码 178-195 doi: 10.1007/s11709-010-0023-4

摘要: The simplified procedure using shear wave velocity measurements is increasingly used to evaluate the seismic liquefaction potential of soils. This procedure is based on finding the boundary separating the liquefaction and non-liquefaction cases through the analysis of liquefaction case histories, following the general format of the Seed-Idriss simplified procedure based on standard penetration test (SPT) data. It is noted that many assumptions have been made in the simplified procedure. This paper develops a simple method for evaluating the liquefaction potential of soils from shear wave velocity by using the optimum seeking method to directly analyze the liquefaction history data and quantify the influence of major factors affecting the liquefactions potential of soils. The factors considered are the earthquake magnitude, the vertical effective overburden stress, the shear wave velocity, the peak acceleration at the ground surface of the site, and the fines content of the soil. The most important factor has been identified as the shear wave velocity. The developed method uses the measured data directly and in a very simple way. Neither stress-correction of shear wave velocity nor calculation of cyclic shear stress as in the simplified procedure is required. Comparisons indicate that the developed simple method has a higher success rate for evaluating liquefaction potential of soils than the simplified procedure. A case study is presented to illustrate the application of the developed simple method and further confirms its accuracy.

关键词: liquefaction     earthquake     simple method     shear wave velocity     case history introduction    

Multi-harmonic forced vibration and resonance of simple beams to moving vehicles

《结构与土木工程前沿(英文)》   页码 981-993 doi: 10.1007/s11709-023-0979-5

摘要: This study modeled the moving-vehicle-induced forcing excitation on a single-span prismatic bridge as a multiple frequency-multiplication harmonic load on the modal coordinates of a linear elastic simple Euler–Bernoulli beam, and investigated the forced modal oscillation and resonance behavior of this type of dynamic system. The forced modal responses consist of multiple frequency-multiplication steady-state harmonics and one damped mono-frequency complementary harmonic. The analysis revealed that a moving load induces high-harmonic forced resonance amplification when the moving speed is low. To verify the occurrence of high-harmonic forced resonance, numerical tests were conducted on single-span simple beams based on structural modeling using the finite element method (FEM) and a moving sprung-mass oscillator vehicle model. The forced resonance amplification characteristics of the fundamental mode for beam response estimation are presented with consideration to different end restraint conditions. The results reveal that the high-harmonic forced resonance may be significant for the investigated beams subjected to vehicle loads moving at specific low speeds. For the investigated single-span simple beams, the moving vehicle carriage heaving oscillation modulates the beam modal frequency, but does not induce notable variation of the modal oscillation harmonic structure for the cases that vehicle of small mass moves in low speed.

关键词: forced vibration     linear Euler beam     moving load     harmonic structure     frequency modulation     end restraints    

Experiments on channel columns with inclined simple edge stiffeners under compression loading

WANG Chungang, ZHANG Yaochun, ZHANG Zhuangnan

《结构与土木工程前沿(英文)》 2007年 第1卷 第3期   页码 312-321 doi: 10.1007/s11709-007-0041-z

摘要: In order to investigate the compression behavior of pin-ended cold-formed channel columns with inclined simple edge stiffeners, a total of 30 pin-ended cold-formed channel columns with three sections (sloping lip stiffener turned at 45º, 90º, and 135º to the flange, respectively) and three different lengths (500 mm, 1 250 mm, and 2 000 mm) were tested. It was found that the inclination angles and loading positions have an obvious effect on compression ultimate load-carrying capacities and failure modes. All three sections have certain post-buckling strength, and the failure modes of most of the specimens contained distortional buckling. The capacity of the specimens with 45º inclined angle for bearing compression is appreciably higher than the other two types of specimens with 90º or 135º inclined angles at the same negative eccentricity, but obviously lower than the other two at the same positive eccentricity. Furthermore, tests were simulated by finite element analysis. Results from the analysis are in great agreement with the experimental data.

关键词: different     post-buckling strength     capacity     distortional buckling     Furthermore    

A simple and cheap method for preparation of coupled ZrO2/ZnO with high photocatalytic activities

WANG Zheng, ZHANG Bingru, LI Fengting

《环境科学与工程前沿(英文)》 2007年 第1卷 第4期   页码 454-458 doi: 10.1007/s11783-007-0072-7

摘要: The objective of this study was to prepare a new photocatalyst with high activities for degradation of organic pollutants. Coupled ZrO/ZnO photocatalyst was prepared with a simple precipitation method with cheap raw

关键词: objective     ZrO/ZnO photocatalyst     photocatalyst     precipitation     degradation    

A simple multi-wave algorithm for the uncapacitated facility location problem

Fred GLOVER, Saïd HANAFI, Oualid GUEMRI, Igor CREVITS

《工程管理前沿(英文)》 2018年 第5卷 第4期   页码 451-465 doi: 10.15302/J-FEM-2018038

摘要:

The multi-wave algorithm (Glover, 2016) integrates tabu search and strategic oscillation utilizing repeated waves (nested iterations) of constructive search or neighborhood search. We propose a simple multi-wave algorithm for solving the Uncapacitated Facility Location Problem (UFLP) to minimize the combined costs of selecting facilities to be opened and of assigning each customer to an opened facility in order to meet the customers’ demands. The objective is to minimize the overall cost including the costs of opening facilities and the costs of allocations. Our experimental tests on a standard set of benchmarks for this widely-studied class of problems show that our algorithm outperforms all previous methods.

关键词: discrete optimization     UFLP     multi-wave optimization     strategic oscillation     tabu search    

连轧张力公式的实验验证和分析

张进之,赵厚信,王喆,王保罗

《中国工程科学》 2008年 第10卷 第4期   页码 73-77

摘要:

连轧张力公式是连轧理论和实践的核心问题,该问题国内外都有大量的研究,20世纪60年代笔者推导了连轧张力微分方程、多机架动态张力公式、稳态张力公式,理论上已作过深入、广泛的分析讨论。日本在20世纪70年代对连轧张力公式进行了理论上的推导和实验验证,特别是浅川基男等人的连轧实验结果更为重要。为此引用了浅川基男的实验数据和宝钢2 050 mm热连轧机上的实测数据,验证了连轧张力公式。

关键词: 连轧张力公式     实验验证     解析解     定常性    

高速铁路900 t简支箱梁建造成套技术与装备

王清明,刘林生

《中国工程科学》 2011年 第13卷 第4期   页码 75-80

摘要:

全面介绍了高速铁路900 t简支箱梁建造的成套技术与装备,包括900 t简支箱梁的预制技术和装备、运输技术和装备、架设技术和装备及特殊工况下900 t简支箱梁建造技术及装备,可供从事高速铁路和桥梁工程技术人员参考。

关键词: 高速铁路     简支箱梁     建造技术    

Three-dimensional composite Li metal anode by simple mechanical modification for high-energy batteries

《能源前沿(英文)》 2023年 第17卷 第5期   页码 569-584 doi: 10.1007/s11708-023-0875-7

摘要: Lithium (Li) metal is believed to be the “Holy Grail” among all anode materials for next-generation Li-based batteries due to its high theoretical specific capacity (3860 mAh/g) and lowest redox potential (−3.04 V). Disappointingly, uncontrolled dendrite formation and “hostless” deposition impede its further development. It is well accepted that the construction of three-dimensional (3D) composite Li metal anode could tackle the above problems to some extent by reducing local current density and maintaining electrode volume during cycling. However, most strategies to build 3D composite Li metal anode require either electrodeposition or melt-infusion process. In spite of their effectiveness, these procedures bring multiple complex processing steps, high temperature, and harsh experimental conditions which cannot meet the actual production demand in consideration of cost and safety. Under this condition, a novel method to construct 3D composite anode via simple mechanical modification has been recently proposed which does not involve harsh conditions, fussy procedures, or fancy equipment. In this mini review, a systematic and in-depth investigation of this mechanical deformation technique to build 3D composite Li metal anode is provided. First, by summarizing a number of recent studies, different mechanical modification approaches are classified clearly according to their specific procedures. Then, the effect of each individual mechanical modification approach and its working mechanisms is reviewed. Afterwards, the merits and limits of different approaches are compared. Finally, a general summary and perspective on construction strategies for next-generation 3D composite Li anode are presented.

关键词: lithium (Li)-ion battery (LIB)     Li metal battery     three-dimensional (3D) composite Li metal anode     mechanical modification     reducing local current density    

以土体应力状态计算边坡安全系数的方法

王国体

《中国工程科学》 2006年 第8卷 第12期   页码 80-84

摘要:

土坡的稳定分析一直是沿着条分法的思路发展的。由于对土体应力状态条件的忽视和条分法本身的缺陷,使得条分法得到的安全系数在工程中的应用面临激烈的挑战。土体不同条件下的应力状态表现为K0效应和变化,它对坡体的安全度影响不可忽视。笔者以考虑土体应力状态为条件,应用土的库伦强度定律和摩尔-库伦准则,推导出平面土坡的安全系数计算公式,与条分法的安全系数对比结果说明这种方法具有概念明确、计算简便、定性可靠的重要特点,可以直接提供于工程应用和参考。

关键词: 侧应力系数K0     初始应力状态     稳定安全系数公式    

A simple digital control algorithm for three phase shunt active filter: simulation and experimentation

Subbaraman SRINATH, Chandan KUMAR, M. P. SELVAN

《能源前沿(英文)》 2014年 第8卷 第1期   页码 119-128 doi: 10.1007/s11708-013-0288-0

摘要: A novel and simple control algorithm using digital signal processor (DSP) has been proposed and realized for a three phase shunt active filter (SAF). The simulation and prototype construction of SAF is conducted to compensate the reactive power and harmonics in a distribution system. The major feature of the proposed algorithm is that it does not require unit vector templates and any transformations for the reference current generation of SAF. This reduces the computational complexity and makes the control flexible and faster. The simulation is conducted in MATLAB/SIMULINK while DSP TMS320LF2407 is employed in the digital implementation of hysteresis current control (HCC) for experimentation. The hardware results correlate with the simulation results in reducing the total harmonic distortion (THD) of the source current and achieving unity power factor.

关键词: shunt active filter (SAF)     power quality     voltage source inverter (VSI)     digital signal processor (DSP)     total harmonic distortion (THD)     power factor improvement    

Lingguizhugan Decoction, a Chinese herbal formula, improves insulin resistance in overweight/obese subjects

《医学前沿(英文)》 2022年 第16卷 第5期   页码 745-759 doi: 10.1007/s11684-021-0880-3

摘要: Lingguizhugan Decoction (LGZG) has been investigated in basic studies, with satisfactory effects on insulin resistance in non-alcoholic fatty liver disease (NAFLD). This translational approach aimed to explore the effect and underlying mechanism of LGZG in clinical setting. A randomized, double-blinded, placebo-controlled trial was performed. A total of 243 eligible participants with NAFLD were equally allocated to receive LGZG (two groups: standard dose and low dose) or placebo for 12 weeks on the basis of lifestyle modifications. The primary efficacy variable was homeostasis model assessment of insulin resistance (HOMA-IR). Analyses were performed in two populations in accordance with body mass index (BMI; overweight/obese, BMI ≥ 24 kg/m2; lean, BMI < 24 kg/m 2). For overweight/obese participants, low-dose LGZG significantly decreased their HOMA-IR level compared with placebo (−0.19 (1.47) versus 0.08 (1.99),P = 0.038). For lean subjects, neither dose of LGZG showed a superior effect compared with placebo. Methylated DNA immunoprecipitation sequencing and real-time qPCR found that the DNA N6-methyladenine modification levels of protein phosphatase 1 regulatory subunit 3A (PPP1R3A) and autophagy related 3 (ATG3) significantly increased after LGZG intervention in overweight/obese population. Low-dose LGZG effectively improved insulin resistance in overweight/obese subjects with NAFLD. The underlying mechanism may be related to the regulation of DNA N6-methyladenine modification of PPP1R3A and ATG3. Lean subjects may not be a targeted population for LGZG.

关键词: insulin resistance     non-alcoholic fatty liver disease     Chinese herbal medicine     randomized controlled trial     DNA N6-methyladenine modification    

A simple umbelliferone based fluorescent probe for the detection of nitroreductase

Adam C. Sedgwick, Alex Hayden, Barry Hill, Steven D. Bull, Robert B. P. Elmes, Tony D. James

《化学科学与工程前沿(英文)》 2018年 第12卷 第2期   页码 311-314 doi: 10.1007/s11705-017-1697-0

摘要: A simple nitrobenzyl-umbelliferone (NCOU1) was synthesised containing a nitroreductase (NTR) trigger moiety. The presence of NTR, resulted in the fragmentation of the parent molecule and release of the highly emissive fluorophore umbelliferone an NTR-catalyzed reduction of the nitro group. In the presence of the NTR enzyme, NCOU1 gave rise to a 5-fold increase in fluorescence intensity at 455 nm and was selective for NTR over other reductive enzymes. These results indicate that NCOU1 can be used as a simple assay for the detection of NTR.

关键词: fragmentation     NCOU1     NTR     nitroreductase     nitrobenzyl-umbelliferone    

A simple, azulene-based colorimetric probe for the detection of nitrite in water

Lloyd C. Murfin, Carlos M. López-Alled, Adam C. Sedgwick, Jannis Wenk, Tony D. James, Simon E. Lewis

《化学科学与工程前沿(英文)》 2020年 第14卷 第1期   页码 90-96 doi: 10.1007/s11705-019-1790-7

摘要: We describe the synthesis and evaluation of an azulene-based chemodosimeter for nitrite. The probe was found to undergo two distinct color changes upon introduction aqueous nitrite ion. A near-instant formation of a grey color provides a qualitative indication of the presence of nitrite, followed by the formation of a deep-yellow/orange color, the endpoint from which quantitative data can be derived. The azulene probe exhibits 1:1 stoichiometry of reaction with nitrite in water, and is selective for nitrite over other anions. The azulene probe was applied to determine nitrite content in cured meat, and compared with the British Standard testing procedure (Griess test). The value obtained from the azulene-based probe agreed closely with the standard test. Our procedure only requires the preparation of one standard solution, instead of the three required for the standard Griess test.

关键词: azulene     nitrite     diazoquinone    

Iteration framework for solving mixed lubrication computation problems

《机械工程前沿(英文)》 2021年 第16卷 第3期   页码 635-648 doi: 10.1007/s11465-021-0632-8

摘要: The general discrete scheme of time-varying Reynolds equation loses the information of the previous step, which makes it unreasonable. A discretization formula of the Reynolds equation, which is based on the Crank–Nicolson method, is proposed considering the physical message of the previous step. Gauss–Seidel relaxation and distribution relaxation are adopted for the linear operators of pressure during the numerical solution procedure. In addition to the convergent criteria of pressure distribution and load, an estimation framework is developed to investigate the relative error of the most important term in the Reynolds equation. Smooth surface with full contacts and mixed elastohydrodynamic lubrication is tested for validation. The asperity contact and sinusoidal wavy surface are examined by the proposed discrete scheme. Results show the precipitous decline in the boundary of the contact area. The relative error suggests that the pressure distribution is reliable and reflects the accuracy and effectiveness of the developed method.

关键词: mixed lubrication     discretization formula     relative error     Reynolds equation     asperity    

标题 作者 时间 类型 操作

Estimation of load and resistance factors using the third-moment method based on the 3P-lognormal distribution

Yan-Gang ZHAO, Zhao-Hui LU

期刊论文

A simple method for evaluating liquefaction potential from shear wave velocity

Lianyang ZHANG,

期刊论文

Multi-harmonic forced vibration and resonance of simple beams to moving vehicles

期刊论文

Experiments on channel columns with inclined simple edge stiffeners under compression loading

WANG Chungang, ZHANG Yaochun, ZHANG Zhuangnan

期刊论文

A simple and cheap method for preparation of coupled ZrO2/ZnO with high photocatalytic activities

WANG Zheng, ZHANG Bingru, LI Fengting

期刊论文

A simple multi-wave algorithm for the uncapacitated facility location problem

Fred GLOVER, Saïd HANAFI, Oualid GUEMRI, Igor CREVITS

期刊论文

连轧张力公式的实验验证和分析

张进之,赵厚信,王喆,王保罗

期刊论文

高速铁路900 t简支箱梁建造成套技术与装备

王清明,刘林生

期刊论文

Three-dimensional composite Li metal anode by simple mechanical modification for high-energy batteries

期刊论文

以土体应力状态计算边坡安全系数的方法

王国体

期刊论文

A simple digital control algorithm for three phase shunt active filter: simulation and experimentation

Subbaraman SRINATH, Chandan KUMAR, M. P. SELVAN

期刊论文

Lingguizhugan Decoction, a Chinese herbal formula, improves insulin resistance in overweight/obese subjects

期刊论文

A simple umbelliferone based fluorescent probe for the detection of nitroreductase

Adam C. Sedgwick, Alex Hayden, Barry Hill, Steven D. Bull, Robert B. P. Elmes, Tony D. James

期刊论文

A simple, azulene-based colorimetric probe for the detection of nitrite in water

Lloyd C. Murfin, Carlos M. López-Alled, Adam C. Sedgwick, Jannis Wenk, Tony D. James, Simon E. Lewis

期刊论文

Iteration framework for solving mixed lubrication computation problems

期刊论文