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Modeling and simulation of landfill gas production from pretreated MSW landfill simulator

Rasool Bux MAHAR,Abdul Razaque SAHITO,Dongbei YUE,Kamranullah KHAN

《环境科学与工程前沿（英文）》 2016年 第10卷 第1期   页码 159-167 doi: 10.1007/s11783-014-0685-6

摘要： The cumulative landfill gas (LFG) production and its rate were simulated for pretreated municipal solid waste (MSW) landfill using four models namely first order exponential model, modified Gompertz model, single component combined growth and decay model and Gaussian function. Considering the behavior of the pretreated MSW landfill, a new multi component model was based on biochemical processes that occurring in landfilled pretreated MSW. The model was developed on the basis of single component combined growth and decay model using an anaerobic landfill simulator reactor which treats the pretreated MSW. It includes three components of the degradation i.e. quickly degradable, moderately degradable and slowly degradable. Moreover, the developed model was statistically analyzed for its goodness of fit. The results show that the multi components LFG production model is more suitable in comparison to the simulated models and can efficiently be used as a modeling tool for pretreated MSW landfills. The proposed model is likely to give assistance in sizing of LFG collection system, generates speedy results at lower cost, improves cost-benefit analysis and decreases LFG project risk. It also indicates the stabilization of the landfill and helps the managers in the reuse of the landfill space. The proposed model is limited to aerobically pretreated MSW landfill and also requires the values of delay times in LFG productions from moderately and slowly degradable fractions of pretreated MSW.

关键词： combine growth and decay model     pretreated municipal solid waste (MSW)     multi component landfill gas (LFG) model    

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Modeling and verifying chlorine decay and chloroacetic acid formation in drinking water chlorination

Wenjun LIU, Shaoying QI,

《环境科学与工程前沿（英文）》 2010年 第4卷 第1期   页码 65-72 doi: 10.1007/s11783-010-0010-y

摘要： This study presents a phenomenological model that can be used by the water professionals to quantify chlorine decay and disinfection byproduct (DBP) formation in water. The kinetic model was developed by introducing the concept of limiting chlorine demand and extending an established reactive species approach. The limiting chlorine demand, which quantifies chlorine reactive natural organic matter (NOM) on an equivalent basis, was mathematically defined by the relation between ultimate chlorine residue and initial chlorine dose. It was found experimentally that NOM in water has limiting chlorine demand that increases with chlorine dose once the ultimate residue is established. These results indicated that the complex NOM has a unique ability to adjust chemically to the change in redox condition caused by the free chlorine. It is attributed mainly to the redundant functional groups that persist in heterogeneous NOM molecules. The results also demonstrated that the effect of chlorine dose on the rate of chlorine decay can be quantitatively interpreted with the limiting chlorine demand. The kinetic model developed was validated for chlorine decay and chloroacetic acid formation in finished drinking water.

关键词： chlorine demand     chlorine decay     chloroacetic acids     disinfection byproducts     model    

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Economic Growth Model Based on Six Basic Factors of Production—Xu Growth Rate Equation

Shou-bo Xu,Zong-yuan Huang

《工程管理前沿（英文）》 2014年 第1卷 第2期   页码 160-175 doi: 10.15302/J-FEM-2014024

摘要： This paper proposes an economic growth model based on the Six Basic Factors of Production and Xu Growth Rate Equation for the first time, which fills-in the deficits of the New Classical Economic Growth Model based on the Solow Model. The empirical analysis indicates that over the past three decades, the consumption of six basic factors of production had complicated relations with economic growth. In some years, the consumption rate of the basic factors of production was meager, but the economy witnessed relatively rocketing growth rate; in some years, the factors of production consumption rate was very high, but the economy growth rate slowed down. In general, economy grows at the expenses of huge consumption of four factors. There is an obvious characteristic of huge input and low efficiency. The average contribution rate of technological advance peaks in the middle, while it drops down at two ends. Noticeably, since 2004, the technology contribution rate generally shows a downward trend, reasons of which should be explored systematically in aspects like economic policy and industry structure with a view to boost further transformation of the macro-economy scientific growth model.

关键词： six basic factors of production     economic growth model     Xu Growth Rate Equation    

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Experimental study of structural damage identification based on modal parameters and decay ratio of acceleration

Zhigen WU, Guohua LIU, Zihua ZHANG

《结构与土木工程前沿（英文）》 2011年 第5卷 第1期   页码 112-120 doi: 10.1007/s11709-010-0069-3

摘要： A novel damage assessment method based on the decay ratio of acceleration signals (DRAS) was proposed. Two experimental tests were used to show the efficiency. Three beams were gradually damaged, and then the changes of dynamic parameters were monitored from initial to failure state. In addition, a new method was compared with the linear modal-based damage assessment using wavelet transform (WT). The results clearly show that DRAS increases in linear elasticity state and microcrack propagation state, while DRAS decreases in macrocrack propagation state. Preliminary analysis was developed considering the beat phenomenon in the nonlinear state to explain the turn point of DRAS. With better sensibility of damage than modal parameters, probably DRAS is a promising damage indicator in damage assessment.

关键词： damage assessment     decay ratio of acceleration signals (DRAS)     wavelet transform (WT)     modal analysis     reinforced concrete beam     beat phenomenon    

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Digital design of a combine harvester using virtual prototyping

YAN Chuliang, LI Jie, ZHANG Shuming, YANG Fangfei

《机械工程前沿（英文）》 2007年 第2卷 第2期   页码 159-163 doi: 10.1007/s11465-007-0026-6

摘要： A parametric feature-based modeling was used to model the parts of a combine harvester. The digital virtual prototyping of the harvester was completed by virtual assembly. The finite element analysis of the vehicle frame was made and the result satisfied the requirements. The vibration sieve, which is a key part of the combine harvester, was simulated and optimized. The excellent parameters of the vibration were gained by optimization. The grain passed through the sieve easily after the optimization and reduced the loss rate and impurity rate in theory.

关键词： excellent     assembly     impurity     harvester     vibration    

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A reliability growth model for 300?MW pumped-storage power units

Jinyuan SHI , Yu YANG , Zhicheng DENG ,

《能源前沿（英文）》 2009年 第3卷 第3期   页码 337-340 doi: 10.1007/s11708-009-0032-y

摘要： A reliability growth model for pumped-storage power units is presented. Ways for estimating and fitting on checking the model’s parameters are given together with analysis results concerning the reliability growth of 300MW pumped-storage power units. On site operation, reliability data show that the reliability growth model conforms to rules of reliability growth tendency. Analysis results of reliability growth indicate that measures taken for improving maintenance and operation by the pumped-storage power companies are effective and that the reliability of the 300MW pumped-storage power units exhibits a rising tendency.

关键词： pump-storage power unit     availability     reliability growth     reliability prediction    

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Availability growth models and verification of power equipment

Jinyuan SHI, Jiamin XU

《能源前沿（英文）》 2021年 第15卷 第2期   页码 529-538 doi: 10.1007/s11708-019-0624-0

摘要： The general availability growth models for large scale complicated repairable system such as electric generating units, power station auxiliaries, and transmission and distribution installations are presented. The calculation formulas for the maintenance coefficient, mathematical expressions for general availability growth models, ways for estimating, and fitting on checking the parameters of the model are introduced. Availability growth models for electric generating units, power station auxiliaries, and transmission and distribution installations are given together with verification examples for availability growth models of 320–1000 MW nuclear power units and 1000 MW thermal power units, 200–1000 MW power station auxiliaries, and 220–500 kV transmission and distribution installations. The verification results for operation availability data show that the maintenance coefficients for electric generating units, power station auxiliaries, transmission and distribution installations conform to the power function, and general availability growth models conform to rules of availability growth tendency of power equipment.

关键词： repairable system     power equipment     electric generating unit     power station auxiliary     transmission and distribution installation     reliability     availability     availability growth model    

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Concurrent fatigue crack growth simulation using extended finite element method

Zizi LU, Yongming LIU,

《结构与土木工程前沿（英文）》 2010年 第4卷 第3期   页码 339-347 doi: 10.1007/s11709-010-0078-2

摘要： In this paper, a concurrent simulation framework for fatigue crack growth analysis is proposed using a novel small time scale model for fatigue mechanism analysis and the extended finite element method (X-FEM) for fatigue crack growth simulation. The proposed small time scale fatigue model does not require the cycle counting as those using the classical fatigue analysis methods and can be performed concurrently with structural/mechanical analysis. The X-FEM greatly facilitates crack growth simulation without remeshing requirements ahead of the crack tip as in the classical finite element method. The basic concept and theory of X-FEM was briefly introduced and numerical predictions of stress intensity factors are verified with reference solutions under both uniaxial and multiaxial loadings. The small time scale fatigue model is integrated into the numerical simulation algorithm for concurrent fatigue crack growth analysis. Model predictions are compared with available experimental observations for model validation.

关键词： small time scale model     extended finite element method (X-FEM)     crack growth     multiaxial    

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Bacteria-mediated tumor-targeted delivery of tumstatin (54-132) significantly suppresses tumor growthin mouse model by inhibiting angiogenesis and promoting apoptosis

《医学前沿（英文）》 2022年 第16卷 第6期   页码 873-882 doi: 10.1007/s11684-022-0925-2

摘要： Tumor growth is an angiogenesis-dependent process and accompanied by the formation of hypoxic areas. Tumstatin is a tumor-specific angiogenesis inhibitor that suppresses the proliferation and induces the apoptosis of tumorous vascular endothelial cells. VNP20009, an attenuated Salmonella typhimurium strain, preferentially accumulates in the hypoxic areas of solid tumors. In this study, a novel Salmonella-mediated targeted expression system of tumstatin (VNP-Tum5) was developed under the control of the hypoxia-induced J23100 promoter to obtain anti-tumor efficacy in mice. Treatment with VNP-Tum5 effectively suppressed tumor growth and prolonged survival in the mouse model of B16F10 melanoma. VNP-Tum5 exhibited a higher efficacy in inhibiting the proliferation and inducing the necrosis and apoptosis of B16F10 cells in vitro and in vivo compared with VNP (control). VNP-Tum5 significantly inhibited the proliferation and migration of mouse umbilical vascular endothelial cells to impede angiogenesis. VNP-Tum5 downregulated the expression of anti-vascular endothelial growth factor A, platelet endothelial cell adhesion molecule-1, phosphorylated phosphoinositide 3 kinase, and phosphorylated protein kinase B and upregulated the expression of cleaved-caspase 3 in tumor tissues. This study is the first to use tumstatin-transformed VNP20009 as a tumor-targeted system for treatment of melanoma by combining anti-tumor and anti-angiogenic effects.

关键词： Salmonella VNP20009     tumstatin     B16F10     melanoma     apoptosis     angiogenesis    

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Effect of atorvastatin on tumor growth and metastasis in a breast cancer cell xenograft model and its

Liu LIU MD, PhD, Yaogui NING MM, Chen CHEN MD, Daowen WANG MD, PhD,

《医学前沿（英文）》 2009年 第3卷 第4期   页码 443-446 doi: 10.1007/s11684-009-0079-5

摘要： This paper aims to evaluate the effects and the possible mechanisms of atorvastatin on tumor growth and metastasis in a xenograft tumor model. Twenty-four female athymic BALB/C mice with MDA-MB-435 xenograft tumors were randomly assigned to three groups: a control group, a low-dose atorvastatin treatment group, and a high-dose atorvastatin treatment group. The mice in the treatment groups began to be administered with atorvastatin (10 or 20 mg/kg per day) when the xenograft tumors reached 1 cm in diameter. At the end of the experiment, the tumor volume and weight and the lung metastasis colonies of each mouse were measured. Western blotting was applied to detect phosphorylation of protein kinase B (PKB, Akt), extracellular signal regulated kinase (ERK), c-Jun N-terminal Kinase (JNK), and the expression of cytochrome P450 (CYP) subtype CYP2J2. Atorvastatin suppressed xenograft tumor growth and metastasis both in the low-dose and the high-dose treatment groups ( < 0.05). Atorvastatin also decreased the phosphorylated Akt (p-Akt) and p-ERK but increased p-JNK expression. However, atorvastatin did not alter the expression of CYP2J2 in tumor tissue. This suggests that atorvastatin has the efficacy of suppressing tumor growth and metastasis . These effects were not dependent on down-regulation of CYP2J2 expression.

关键词： atorvastatin     xenograft tumor     metastasis     CYP2J2    

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Influence of welding residual stresses on the ductile crack growth resistance of circumferentially cracked

Xiaobo REN, Odd M. AKSELSEN, B?rd NYHUS, Zhiliang ZHANG

《结构与土木工程前沿（英文）》 2012年 第6卷 第3期   页码 217-223 doi: 10.1007/s11709-012-0169-3

摘要： Welding residual stress is one of the main concerns for fabrication and operation of steel structures due to its potential effect on structural integrity. This paper focuses on the effect of welding residual stress on the ductile crack growth resistance of circumferentially cracked steel pipes. Two-dimensional axi-symmetry model has been used to simulate the pipe. Residual stresses were introduced into the model by using so-called eigenstrain method. The complete Gurson model has been employed to calculate the ductile crack growth resistance. Results show that residual stresses reduce the ductile crack growth resistance. However, the effect of residual stresses on ductile crack growth resistance decreases with the increase of crack growth. The effect of residual stress has also been investigated for cases with different initial void volume fraction, material hardening and crack sizes.

关键词： residual stress     ductile crack growth resistance     complete Gurson model     eigenstrain method    

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大空间内着火位置对火灾增长的影响

石龙,张瑞芳, 谢启源,付丽华

《中国工程科学》 2008年 第10卷 第11期   页码 37-42

摘要：

以大空间展厅为例，利用火源辐射模型和烟气辐射模型并结合CFAST6.0区域模拟软件的计算结果，对比分析了大空间内不同着火位置下火灾增长的情况。研究结果表明仅考虑火源热辐射的情况下，展厅内着火位置越处于左右中间对称处，其火灾增长越快，热释放速率峰值也越大，达到热释放速率峰值的时间和火灾的持续时间越短，处于展厅中心位置时所有值达峰值。对火源热辐射和烟气辐射综合考虑时，到达热释放速率峰值时间与火灾持续时间的规律同仅考虑火源辐射模型时一致，但热释放速率峰值均有不同程度的提高。

关键词： 火灾增长     大空间着火位置     火灾场景设置     火源辐射模型     烟气辐射模型    

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Simulation of cohesive crack growth by a variable-node XFEM

Weihua FANG, Jiangfei WU, Tiantang YU, Thanh-Tung NGUYEN, Tinh Quoc BUI

《结构与土木工程前沿（英文）》 2020年 第14卷 第1期   页码 215-228 doi: 10.1007/s11709-019-0595-6

摘要： A new computational approach that combines the extended finite element method associated with variable-node elements and cohesive zone model is developed. By using a new enriched technique based on sign function, the proposed model using 4-node quadrilateral elements can eliminate the blending element problem. It also allows modeling the equal stresses at both sides of the crack in the crack-tip as assumed in the cohesive model, and is able to simulate the arbitrary crack-tip location. The multiscale mesh technique associated with variable-node elements and the arc-length method further improve the efficiency of the developed approach. The performance and accuracy of the present approach are illustrated through numerical experiments considering both mode-I and mixed-mode fracture in concrete.

关键词： extended finite element method     cohesive zone model     sign function     crack propagation    

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Solubility of CO in solid-state PET measured by pressure-decay method

CHEN Miaocan, ZHAO Ling, LIU Tao, WU Jiangwei, YUAN Weikang

《化学科学与工程前沿（英文）》 2008年 第2卷 第2期   页码 214-219 doi: 10.1007/s11705-008-0040-1

摘要： The solubility of CO in solid-state PET was measured using a pressure-decay method. In order to calculate the solubility of CO in the amorphous region of PET, the crystallinity of solid state PET dissolved in CO at different pressures and temperatures was measured by differential scanning calorimetry (DSC). The solubility increases with increasing pressure and it follows a linear relationship and obeys Henry’s law when the pressure is below 8 MPa. The effect of temperature on solubility is weak and the solubilities at different temperatures are almost the same under low pressures. At higher pressure, the solubility decreases with an increase in temperature. The solubility of CO in the amorphous region of PET at 373.15 K, 398.15 K and 423.15 K was correlated with the Sanchez-Lacombe equation of state with a maximal correlation error of 6.69%.

关键词： Sanchez-Lacombe equation     solid-state PET     different     relationship     calorimetry    

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Clinical evaluation of recombinant human growth hormone injection in children with growth hormone deficiency

Ling HOU, Xiaoping LUO, Minlian DU, Huamei MA, Chunxiu GONG, Yuchuan LI, Shuixian SHEN, Zhuhui ZHAO, Li LIANG, Guanping DONG, Chaoying YAN, Hongwei DU

《医学前沿（英文）》 2009年 第3卷 第2期   页码 171-176 doi: 10.1007/s11684-009-0027-4

摘要： Recombinant human growth hormone (rhGH) has been widely used in the clinical treatment of growth hormone deficiency. To simplify the injection process and increase drug compliance, application of the GH injection has become a new treatment plan in recent years. The purpose of the current study was to evaluate the efficacy and safety of rhGH injection for the treatment of growth hormone deficiency (GHD) in children in China. In a nationwide, noncomparative, prospective, randomized, open trial, 31 children with confirmed complete GHD received subcutaneous injection of rhGH at 0.25 mg/kg·wk (0.107 IU/kg·d). The injection was given daily and the total weekly amount was separated into 6-7 injections. The patients were followed up at 3-month intervals and the treatment duration was 12 months. The height (HT), annual growth velocity (GV), mean height standard deviation score (HT SDS), blood serum insulin-like growth factor I (IGF-I), insulin-like growth factor binding protein 3 (IGFBP-3), and bone maturity before and after treatment were compared, and the safety of the treatment was analyzed. The mean HT, GV, and HT SDS were increased from 109.0±14 cm, 2.7±0.9 cm/yr, and -4.62±1.46 at baseline to 121.8±13.4 cm, 12.9±3.3 cm/yr, and -2.47±1.86 after 12 months of treatment, respectively ( <0.001). At the same time, blood IGF-I and IGFBP-3 were increased significantly [41.27±64.43 μg/L 159.21±167.92 μg/L and 1540.00±1325.11 mg/L 3533.93±1413.82 mg/L, respectively ( <0.001)]. The bone age assessments performed 6 and 12 months after the treatment showed that no advanced bone maturation was noted. No serious adverse events occurred during the treatment, and the drug-related adverse events were mainly decreased thyroid function. We conclude that rhGH injection is a safe and effective drug for treatment of growth hormone deficiency in children.

关键词： recombinant human growth hormone     injection     growth hormone deficiency    

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标题 作者 时间 类型 操作

Modeling and simulation of landfill gas production from pretreated MSW landfill simulator

Rasool Bux MAHAR,Abdul Razaque SAHITO,Dongbei YUE,Kamranullah KHAN

期刊论文

Modeling and verifying chlorine decay and chloroacetic acid formation in drinking water chlorination

Wenjun LIU, Shaoying QI,

期刊论文

Economic Growth Model Based on Six Basic Factors of Production—Xu Growth Rate Equation

Shou-bo Xu,Zong-yuan Huang

期刊论文

Experimental study of structural damage identification based on modal parameters and decay ratio of acceleration

Zhigen WU, Guohua LIU, Zihua ZHANG

期刊论文

Digital design of a combine harvester using virtual prototyping

YAN Chuliang, LI Jie, ZHANG Shuming, YANG Fangfei

期刊论文

A reliability growth model for 300?MW pumped-storage power units

Jinyuan SHI , Yu YANG , Zhicheng DENG ,

期刊论文

Availability growth models and verification of power equipment

Jinyuan SHI, Jiamin XU

期刊论文

Concurrent fatigue crack growth simulation using extended finite element method

Zizi LU, Yongming LIU,

期刊论文

Bacteria-mediated tumor-targeted delivery of tumstatin (54-132) significantly suppresses tumor growthin mouse model by inhibiting angiogenesis and promoting apoptosis

期刊论文

Effect of atorvastatin on tumor growth and metastasis in a breast cancer cell xenograft model and its

Liu LIU MD, PhD, Yaogui NING MM, Chen CHEN MD, Daowen WANG MD, PhD,

期刊论文

Influence of welding residual stresses on the ductile crack growth resistance of circumferentially cracked

Xiaobo REN, Odd M. AKSELSEN, B?rd NYHUS, Zhiliang ZHANG

期刊论文

大空间内着火位置对火灾增长的影响

石龙,张瑞芳, 谢启源,付丽华

期刊论文

Simulation of cohesive crack growth by a variable-node XFEM

Weihua FANG, Jiangfei WU, Tiantang YU, Thanh-Tung NGUYEN, Tinh Quoc BUI

期刊论文

Solubility of CO in solid-state PET measured by pressure-decay method

CHEN Miaocan, ZHAO Ling, LIU Tao, WU Jiangwei, YUAN Weikang

期刊论文

Clinical evaluation of recombinant human growth hormone injection in children with growth hormone deficiency

Ling HOU, Xiaoping LUO, Minlian DU, Huamei MA, Chunxiu GONG, Yuchuan LI, Shuixian SHEN, Zhuhui ZHAO, Li LIANG, Guanping DONG, Chaoying YAN, Hongwei DU

期刊论文