A multi-objective gravitational search algorithm based approach of power system stability enhancement with UPFC

On the basis of the theoretical analysis of a single-machine infinite-bus (SMIB),using the modified linearized Phillips-Heffron model installed with unified power flow controller (UPFC),the potential of the UPFC supplementary controller to enhance the dynamic stability of a power system is evaluated by measuring the electromechanical controllability through singular value decomposition (SVD) analysis.This controller is tuned to simultaneously shift the undamped electromechanical modes to a prescribed zone in the s-plane.The problem of robust UPFC based damping controller is formulated as an optimization problem according to the eigenvalue-based multi-objective function comprising the damping factor,and the damping ratio of the undamped electromechanical modes to be solved using gravitational search algorithm (GSA) that has a strong ability to find the most optimistic results.The different loading conditions are simulated on a SMIB system and the rotor speed deviation,internal voltage deviation,DC voltage deviation and electrical power deviation responses are studied with the effect of this flexible AC transmission systems (FACTS) controller.The results reveal that the tuned GSA based UPFC controller using the proposed multi-objective function has an excellent capability in damping power system with low frequency oscillations and greatly enhances the dynamic stability of the power systems.

Effect of welding parameters on the heat-affected zone of AISI409 ferritic stainless steel

One of the main problems during the welding of ferritic stainless steels is severe grain growth within the heat-affected zone （HAZ） In the present study, the microstmctural characteristics of tungsten inert gas （TIG） welded AISI409 ferritic stainless steel were investigated by electron backscattered diffraction （EBSD）, and the effects of welding parameters on the grain size, local misorientation, and low-angle grain boundaries were studied. A 3-D finite element model （FEM） was developed to predict the effects of welding parameters on the holding time of the HAZ above the critical temperature of grain growth. It is found that the base metal is not fully recrystallized. During the welding, complete recrystallization is followed by severe grain growth. A decrease in the number of low-angle grain boundaries is observed within the HAZ. FEM results show that the final state of residual sWains is caused by competition between welding plastic strains and their release by recrystallization. Still, the decisive factor for grain growth is heat input.

Effects of renal artery stenosis on realistic model of abdominalaorta and renal arteries incorporating fluid-structureinteraction and pulsatile non-Newtonian blood flow

The effects of the renal artery stenosis （RAS） on the blood flow and vessel walls are investigated. The pulsatile blood flow through an anatomically realistic model of the abdominal aorta and renal arteries reconstructed from CT-scan images is simulated, which incorporates the fluid-structure interaction （FSI）. In addition to the investigation of the RAS effects on the wall shear stress and the displacement of the vessel wall, it is determined that the RAS leads to decrease in the renal mass flow. This may cause the activation of the renin-angiotension system and results in severe hypertension.

Artificial Neural Network Ability in Evaluation of Random Wave-Induced Inline Force on A Vertical Cylinder

An approach based on artificial neural network （ANN） is used to develop predictive relations between hydrodynamic inline force on a vertical cylinder and some effective parameters. The data used to calibrate and validate the ANN models are obtained from an experiment. Multilayer feed-forward neural networks that are trained with the back-propagation algorithm are constructed by use of three design parameters （i.e. wave surface height, horizontal and vertical velocities） as network inputs and the ultimate inline force as the only output. A sensitivity analysis is conducted on the ANN models to investigate the generalization ability （robustness） of the developed models, and predictions from the ANN models are compared to those obtained from Morison equation which is usually used to determine inline force as a computational method. With the existing data, it is found that least square method （LSM） gives less error in determining drag and inertia coefficients of Morison equation. With regard to the predicted results agreeing with calculations achieved from Morison equation that used LSM method, neural network has high efficiency considering its convenience, simplicity and promptitude. The outcome of this study can contribute to reducing the errors in predicting hydrodynamic inline force by use of ANN and to improve the reliability of that in comparison with the more practical state of Morison equation. Therefore, this method can be applied to relevant engineering projects with satisfactory results

Numerical and experimental investigations of weld pool geometry in GTA welding of pure aluminum

A 2-D numerical model was developed to predict the shape of weld pool in stationary GTA welding of commercial pure aluminium,without considering fluid flow in the weld pool.A Gaussian current density and heat input distribution on the surface of the workpiece were considered.The parameters of Gaussian distribution were modified by comparing calculated results with experimental ones.It was found that these distribution parameters are functions of applied current and arc length.Effects of arc length,applied current and welding time on the geometry of the weld pool were investigated.To check the validity of the model,a series of experiments were also conducted.In general,the agreement between calculated overall shape of the weld pool and the experimental one was acceptable,especially in low applied currents.Therefore,it can be concluded that in pure aluminium,the heat conduction is dominant mechanism of heat transfer in the weld pool.

Effect of onion (<i>Allium cepa</i>L.) as an antibiotic growth promoter substitution on performance, immune responses and serum biochemical parameters in broiler chicks

This experiment was conducted to evaluate the effect of onion (Allium cepa L.) as an antibiotic growth promoter substitute on growth performance, immune responses and serum biochemistry in broilers. A total of 192 one-d-old as hatched broiler chicks (Ross 308) were weighed and randomly allocated to four treatment groups, each with 4 replicate pens of 12 chicks. The dietary treatments consisted of the basal diet (control), antibiotic (15 mg Virginiamycin/kg), and control +10 or 30 g fresh onion bulb/kg diet. Body weights of broilers were determined at d 1, 21 and 42, feed intake was determined at the same periods, and feed conversion ratio was calculated accordingly. At 14th and 21st days blood samples were taken for measuring antibody titers against NDV and at 42nd day for biochemical analysis. At d 42, two birds per replicate were slaughtered for determination of lymphoid organ weights. Dietary supplementation of30 g/kg onion increased final body weight of broilers at 42nd d of age compared to the other treatments (P < 0.05). Birds fed30 gonion/kg in the diet had the highest feed intake than other treatments at different growth periods (P < 0.05). Dietary treatments failed to induce any significant effect on antibody titers against NDV, although the weight of lymphoid organs was significantly (P Broilers receiving30 g/kg onion had a significantly higher HDL and lower triglyceride concentrations compared to control groups (P . Feeding30 g/kg onion resulted in a marked reduction in the concentration of the glucose compared to control groups (P . The results suggested that dietary inclusion of30 g/kg onion can be applied as alternatives to in-feed antibiotics for broiler diets.

二氧化锡纳米粒子催化四组分Hantzsch缩合合成多氢喹啉衍生物(英文)

Tin dioxide (SnO2 ) nanoparticles efficiently catalyzed unsymmetrical four-component Hantzsch condensations of various aldehydes, dimedone, ethyl acetoacetate, and ammonium acetate to form polyhydroquinoline derivatives in excellent yields. This novel method offers several advantages over the traditional method of synthesizing these compounds, including safety, mild conditions, short reaction times, high yields, and an easy workup.

Managed Pressure Drilling Technology,As the Lost Piece of the Drilling Puzzle,Results in More Economical Benefits

The economics of drilling wells is important as we drill deeper wells whether offshore or onshore. Drilling-related problems,including stuck pipe,lost circulation,and excessive mud cost,show the need for better drilling technology.If we can solve these problems,the economics of drilling the wells will improve,thus enabling the industry to drill wells that were previously uneconomical.Managed pressure drilling techniques,at one time,having

Simultaneous Effects of Hydrostatic Pressure and Conduction Band Non-parabolicity on Binding Energies and Diamagnetic Susceptibility of a Hydrogenic Impurity in Spherical Quantum Dots

与在中心上 hydrogenic 杂质的抗磁的危险性一起的 1S， 2S，和 2P 状态的有约束力的精力上的传导乐队 non-parabolicity 和静水力学的压力的同时的效果在典型 GaAs/AlxGa1xAs 球形的量点限制了理论上用矩阵 diagonalization 方法被调查。在这方面，乐队 non-parabolicity 的效果用 LuttingerKohn 有效集体方程被执行了。有约束力的精力和 hydrogenic 杂质的抗磁的危险性面对传导乐队 non-parabolicity 效果作为点半径的一个函数和压力的不同的值被计算。结果我们到达了如下：乐队边 non-parabolicity 的加入增加有约束力的精力和减少为一个给定的压力和半径的抗磁的危险性的绝对值；有约束力的精力增加和有增加压力的抗磁的危险性还原剂的大小。

Quantum Gravitational Effects on Tunneling Rate of Reissner-Nordstroum Black Hole Emission and Generalized Second Law

The semi-classical black hole tunneling radiation (Parikh-Wilczek tunneling proposal) is calculated undera minimal length uncertainty analysis.It is shown that,the generalized second law of thermodynamics may bound thetunneling probability radiation of a Reissner-Nordstrom black hole radiation.

Theoretical Studies on Interaction Between Methanol and Functionalized Single-Walled Carbon Nanotubes

We study the adsorption of a methanol molecule on single-walled carbon nanotubes (SWCNTs) with various diameters and chiral angles by using the density functional theory based calculations.We find that methanol prefers to be adsorbed physically on the exterior surface of chiral nanotubes in comparison to the armchair and zigzag tubes with binding energy of about-2.76 kcal/mol,which is consistent with recent experimental and theoretical investigation results.We further consider the adsorption of methanol on the exterior surface and edge site of functionalized SWCNTs. The obtained results indicate that the binding energy of methanol is significantly increased for adsorption on the sidewall of functionalized nanotubes.It is also found that the adsorption of methanol at the edge site of both functionalized and pristine SWCNT is remarkably different (chemisoption process) in comparison to the exterior sidewall of the tubes. Furthermore,the electronic structures and MuUiken charge population of the considered complexes at their ground state are discussed within the context.

A novel adaptive finite-time controller for synchronizing chaotic gyros with nonlinear inputs

In this paper, the problem of the finite-time synchronization of two uncertain chaotic gyros is discussed. The parameters of both the master and the slave gyros are assumed to be unknown in advance. The effects of model uncertainties and input nonlinearities are also taken into account. An appropriate adaptation law is proposed to tackle the gyros＇ unknown parameters. Based on the adaptation law and the finite-time control technique, proper control laws are introduced to ensure that the trajectories of the slave gyro converge to the trajectories of the master gyro in a given finite time. Simulation results show the applicability and the efficiency of the proposed finite-time controller.

在玻璃表面上短时接触硅藻土和多杀菌素对四纹豆象的致死效应和亚致死效应(英文)

四纹豆象Callosobruchus maculatus(F.)是伊朗豇豆种子上的主要贮藏害虫。控制这一害虫时,用生物杀虫剂比用常规杀虫剂更为合适。本研究评价了室内条件下在玻璃表面上硅藻土和多杀菌素对四纹豆象成虫的致死效应和亚致死效应。结果表明:硅藻土处理24h和48h后,对四纹豆象成虫的LC50值分别为1.47和0.2g/m2;多杀菌素处理24h和48h后,对四纹豆象成虫的LC50值分别为102.9和68.8mgai/L,说明两种化合物都对四纹豆象成虫具有较高的急性毒性。通过检测生物学参数,研究了LC20浓度的硅藻土和多杀菌素对四纹豆象的亚致死效应。LC20浓度的硅藻土和多杀菌素使四纹豆象成虫的繁殖力分别比对照降低了71.5%和17.2%,卵孵化率降低了57.5%和27.8%,成虫寿命缩短了74.7%和17.1%。接触LC20浓度的硅藻土和多杀菌素使这一害虫的蛹期分别比对照延长了4.8%和2.3%。亚致死效应研究表明,硅藻土和多杀菌素对四纹豆象的生命参数均产生了负面影响。总之,致死效应和亚致死效应综合显示,硅藻土在防治四纹豆象上具有较大的潜力。

First Principles Study on Encapsulation of Alkali Metals into ZnO Nanocage

进 Zn12O12 nanocage 的碱金属(李， Na， K，和 Rb ) 的封装用密度被调查了功能的理论。李和 Na 原子的封装被发现在 298 K 和 100 kPa 热力学地有利，与否定吉布斯一起大约 130.12 和 68.43 kJ/mol 的免费精力变化 G 分别地。由增加包含的原子的尺寸这个过程变得不太有利以便在 K 和 Rb 封装的情况中 G 价值是积极的。结果显示 LUMO，费密水平，并且特殊，簇的人被转移到更高的精力以便簇的 HOMO-LUMO 差距显著地在所有案例中被缩小。在碱金属的封装以后，簇的工作功能由于费密水平的移动被减少到更高的精力。因此，从 Zn12O12 簇的射出的电子电流密度将被增加。

Effect of galvanic contact on the flotability of galena in the presence and absence of a collector

In this paper,the effect of various electrochemical environments in the galena flotation is investigated.The electrochemical environments consisted of a ball mill for grinding of galena ore and a Denver flotation cell for flotation of galena in the laboratory scale.In order to achieve the maximum recovery with sodium hyposulfite,the concentrations of 0.06 and 0.12 M of air and nitrogen gases have been used to control the pulp potential in the Denver flotation cell.The galena sample was from the ''Era mine'' which is located in the Kiyasar area,north of Iran.This mine contains:Galena(PbS) at least 22%,Fluorite(CaF 2) 73.37%,Quartz(SiO 2) 2.54% and other minerals such as Cerussite(PbCO 3) and Kaolinite(Al 2 Si 2 O 5(OH) 4).Flotation of Galena was conducted in a 0.12 M of sodium hyposulfite solution.It was found that the amount of recovery by this process was 85% and 63% in the presence and absence of potassium amyl xanthate(KAX) and at an estimated potential of 280 to 350 mV respectively while the recovery was 70% and 52% at an approximate potential of 175 to 210 mV in water in the presence and absence of collector(KAX).

Quantitative Structure-retention Relationship Analysis of Nanoparticle Compounds by GA-PLS,GA-KPLS and L-M ANN

Genetic algorithm and partial least square（GA-PLS）,kernel PLS（KPLS） and Levenberg-Marquardt artificial neural network（L-M ANN） techniques were used to investigate the correlation between retention time（RT） and descriptors for 15 nanoparticle compounds obtained by the comprehensive two-dimensional gas chromatography system（GC × GC）.Application of the dodecanethiol monolayer-protected gold nanoparticle（MPN） column was for a high-speed separation as the second column of GC × GC.The L-M ANN model with the final optimum network architecture of [13-5-1] gave a significantly better performance than the other models.This is the first research on the quantitative structure-retention relationship（QSRR） of nanoparticle compounds using the GA-PLS,GA-KPLS and L-M ANN.

Evaluation of imatinib mesylate(Gleevec) on KAI1/CD82 gene expression in breast cancer MCF-7 cells using quantitative real-time PCR

Objective: To evaluate the effect of imatinib mesylate on cell viability, anti cancer effect through modulation of KAI1/CD82 gene expression in breast cancer MCF-7 cell line.Methods: The effects of imatinib mesylate on cell viability in MCF-7 cell line were assessed using MTT assay and IC_(50) value was determined. GAPDH and KAI1/CD82 were selected as reference and target genes, respectively. Quantitative real time PCR technique was applied for investigation of KAI1/CD82 gene expression in human breast cancer MCF-7 cells. Subsequently, the quantity of KAI1 compared to GAPDH gene expressions were analyzed using the formula; 2^(-DDCt).Results: Imatinib was showed to have a dose-dependent inhibitory effect on the viability of MCF-7 cells. CD82/GAPDH gene expression ratios were 1.322 ± 0.030(P > 0.05),2.052 ± 0.200(P < 0.05), 2.151 ± 0.270(P < 0.05) for 10, 20 and 40 mmol/L of imatinib concentrations.Conclusions: Based on the present data, imatinib mesylate might modulate metastasis by up-regulating KAI1/CD82 gene expression in human breast MCF-7 cancer cell line.

Structural and Optical Characteristics of Silica Nanotubes Using CNTs as Template

Silica coated multi-wall carbon nanotubes(MWCNTs),silica@MWCNTs and nanocomposites were synthesized by a sol-gel method.By using the synthesized nanocomposites and also CNTs as templates,silica nanotubes(silica-NTs) were prepared.The optical properties of fabricated nanocomposites and nanotubes were characterized by back-scattering micro Raman,UV/Vis/NIR and FT-IR spectra,which show the presence of CNTs structure in the nanocomposites.UV/Vis/NIR and FT-IR spectra also show the presence of silica compounds.The recorded spectra from UV/Vis/NIR and FT-IR also confirm the presence of silica compounds in the nanotubes.The results of FE-SEM imaging data indicate that the synthesized samples are MWCNTs coated uniformly by silica molecules,which act as the template to synthesize silica-NTs.