Evaluation of seismic reliability of gravity dam-reservoir-inhomogeneous foundation coupled system

The seismic performance of gravity dam-reservoir-foundation coupled system is investigated utilizing probabilistic approach. In this research, the uncertainties associated with modeling parameters are incorporated in nonlinear response history simulations to realistically quantify their effects on the seismic performance of the system. The methodology is applied to Pine Flat gravity dam and the foundation is considered to be inhomogeneous assuming a constant spatial geometry but with various rock material properties. The sources of uncertainty are taken into account in the reliability analysis using Latin Hypercube Sampling procedure. The effects of the deconvolution process, number of samples, and foundation inhomogeneity are investigated.     

Alcalase-generated proteolysates of stone fish (Actinopyga lecanora) flesh as a new source of antioxidant peptides

In the present study, the alcalase-generated proteolysates obtained after 8 h of proteolysis of stone fish flesh showed the most potent antioxidant activity in terms of DPPH^? radical scavenging activity (77.43%, IC₅₀ of 0.5 mg/mL), ABTS^? radical scavenging activity (92.73%, IC₅₀ of 0.33 mg/mL) and FRAP value (39.2 mmol/100 mL FeSO₄). These proteolysates profiled and characterized as antioxidative peptides. The proteolysates were initially subjected to ultrafiltration using MWCO Spin-X UF. Potent fractions were further characterized based on hydrophobicity using reversed-phase high-performance liquid chromatography (RP-HPLC) and isoelectric point using an OFFGEL isoelectric focusing fractionator. Results indicated that most of the antioxidative peptides found in fractions with a molecular weight (MW) of less than 2 kDa, hydrophilic (hydrophilicity >80%) and basic (pI = 9.7). The final purified fraction with the highest antioxidant activity was selected for peptide identification and sequencing using Q-TOF mass spectrometry. A total of four peptides were identified, from which Peptide 1 (GVSGLHID) showed the highest antioxidant activity and this has potential as a novel bioingredient of nutraceuticals and functional foods to promote human health.     

Field Evaluation of Soil Liquefaction and Its Confrontation in Fine-Grained Sandy Soils (Case Study: South of Hormozgan Province)

Journal of Mining Science - The phenomenon of liquefaction is one of the most important aftermaths of earthquakes. Whereas deposits subject to liquefaction are possible in city regions, during an...     

Dynamic assessment of capacity investment in electricity market considering complementary capacity mechanisms

This paper proposes a decentralized market-based model for long-term capacity investment decisions in a liberalized electricity market. Investment decisions are fundamentally based on total revenues gained by investors. In most electricity markets, the complementary mechanisms are designed to ensure a desired level of reliability while covering investment costs of the suppliers. In such an environment, investment decisions are highly sensitive to expectation of price signals in both of energy market and capacity mechanisms. In this work, the system dynamics concepts are used to model the structural characteristics of electricity market such as, long-term firms’ behavior and relationships between variables, feedbacks, and time delays by appropriately bundling the energy market and capacity mechanisms. The market oriented capacity price as well as non-competitive capacity payments and a proposed hybrid capacity mechanism are linked with the energy market in the model. Such a decision model enables both the generation companies and the regulators gaining perfect insights into the possible consequences of different decisions they make under different policies and market conditions. In order to examine the performance of the electricity market with different capacity mechanisms, a case study is presented which exhibits the effectiveness of the proposed model.     

基于高光谱成像技术的药用胶囊铬含量快速检测方法研究

研究了基于高光谱成像技术快速检测药用胶囊铬含量的方法。首先应用传统的原子吸收分光法对药用明胶空心硬胶囊分析结果作为对照组,再对1048个胶囊（含正常和含有重金属铬）样本的高光谱数据进行降维和定性分析,最后选择偏最小二乘判别分析方法对光谱数据进行处理。当用4个偏最小二乘算子（LV）作为偏最小二乘法模型中的输入特征,分类准确率可达100%,2种样本的交叉验证和样本预测相关系数分别为0.923和0.972;敏感度与特异度均为100%。     

Seismic assessment of RC core‐wall building capable of three plastic hinges with outrigger

In a core‐wall structure with buckling restrained braces (BRB) outrigger, locations of the plastic hinges are influenced by the outrigger action. Therefore, the designer should consider the issue and use suitable details in the plastic hinge area. The essential questions that arise here are the plastic hinge location and the design moment demand used for design of this kind of structure. In this paper, responses of the core‐wall buildings with BRB outrigger designed by using the traditional response spectrum analysis procedure are assessed by implementing the nonlinear time history analysis. The result demonstrates that the plasticity can extend over anywhere within the core‐walls specially, at the base and above or below the outrigger levels. Formation of three plastic hinges in the core‐wall is recognized suitable for the system. To control the plasticity extension in the core‐wall, it is recommended that a new modal combination method be applied to calculate the moment strength of the three plastic hinges over the height. A capacity design concept is used to design other regions of the core‐wall where the plasticity does not extend to. The proposed procedure improves behavior of the system by restricting the plasticity extension to the predefined plastic hinge regions. Copyright © 2016 John Wiley & Sons, Ltd.     

A Lagrangian model for hardening behaviour of materials at finite deformation based on the right plastic stretch tensor

In this paper a modified multiplicative decomposition of the right stretch tensor is proposed and used for finite deformation elastoplastic analysis of hardening materials. The total symmetric right stretch tensor is decomposed into a symmetric elastic stretch tensor and a non-symmetric plastic deformation tensor. The plastic deformation tensor is further decomposed into an orthogonal transformation and a symmetric plastic stretch tensor. This plastic stretch tensor and its corresponding Hencky’s plastic strain measure are then used for the evolution of the plastic internal variables. Furthermore, a new evolution equation for the back stress tensor is introduced based on the Hencky plastic strain. The proposed constitutive model is integrated on the Lagrangian axis of the plastic stretch tensor and does not make reference to any objective rate of stress. The classic problem of simple shear is solved using the proposed model. Results obtained for the problem of simple shear are identical to those of the self-consistent Eulerian rate model based on the logarithmic rate of stress. Furthermore, extension of the proposed model to the mixed nonlinear isotropic/kinematic hardening behaviour is presented. The model is used to predict the nonlinear hardening behaviour of SUS 304 stainless steel under fixed end finite torsional loading. Results obtained are in good agreement with the available experimental results reported for this material under fixed end finite torsional loading.     

Modeling the Flow Curve Characteristics of 410 Martensitic Stainless Steel Under Hot Working Condition

The hot deformation behavior of AISI 410 martensitic stainless steel was investigated by conducting hot compression tests between 1173 K (900 °C) and 1423 K (1150 °C) and between strain rates of 0.001 s⁻¹ to 1 s⁻¹. The hyperbolic sine function described the relation well between flow stress at a given strain and the Zener–Hollomon parameter (Z). The variation of flow stress with deformation temperature gave the average value of apparent activation energy as 448 kJ/mol. The strain and stress corresponding to two important points associated with flow curve (i.e., peak strain and the onset of steady-state flow) were related to the Z parameter using power-law equations. A model also was proposed based on the Johnson–Mehl–Avrami–Kolmogorov (JMAK) equation to estimate the fractional softening of dynamic recrystallization at any given strain. This model can be used readily for the prediction of flow stress. The values of n and k, material constants in the JMAK equation, were determined for the studied material. The strains regarding the peak and the onset of steady-state flow were formulated in term of applied strain rate and the constants of the JMAK equation. A good agreement was found between the predicted strains and those obtained by the experimental work.     

Multidisciplinary heat generating logic block placement optimization using genetic algorithm

A multidisciplinary optimization methodology for placement of heat generating semiconductor logic blocks on integrated circuit chips is presented. The methodology includes thermal and wiring length criteria, which are optimized simultaneously using a genetic algorithm. An effective thermal performance prediction methodology based on a superposition method is used to determine the temperature distribution on a silicon chip due to multiple heat generating logic blocks. Using the superposition method, the predicted temperature distribution in the silicon chip is obtained in much shorter time than with a detailed finite element model and with comparable accuracy. The main advantage of the present multidisciplinary design and optimization methodology is its ability to handle multiple design objectives simultaneously for optimized placement of heat generating logic blocks. Capabilities of the present methodology are demonstrated by applying it to several standard benchmarks. The multidisciplinary logic block placement optimization results indicate that the maximum temperature on a silicon chip can be reduced by up to 7.5 °C, compared to the case in which only the wiring length is minimized.