Search results for: vibration compensation
483 Nonuniformity of the Piston Motion in a Radial Aircraft Engine
Authors: K. Pietrykowski, M. Bialy, M. Duk
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One of the main disadvantages of radial engines is non-uniformity of operating cycles of each cylinder. This paper discusses the results of the kinematic analysis of pistons motion of the ASz-62IR radial engine. The ASz-62IR engine is produced in Poland and mounted in the M-18 Dromader and the An-2. The results are shown as the courses of the motion of the pistons. The discrepancies in the courses for individual pistons can result in different masses of the charge to fill the cylinders. Besides, pistons acceleration of individual cylinders is different, which triggers an additional vibration in the engine.Keywords: nonuniformity, kinematic analysis, piston motion, radial engine
Procedia PDF Downloads 385482 Improving the LDMOS Temperature Compensation Bias Circuit to Optimize Back-Off
Authors: Antonis Constantinides, Christos Yiallouras, Christakis Damianou
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The application of today's semiconductor transistors in high power UHF DVB-T linear amplifiers has evolved significantly by utilizing LDMOS technology. This fact provides engineers with the option to design a single transistor signal amplifier which enables output power and linearity that was unobtainable previously using bipolar junction transistors or later type first generation MOSFETS. The quiescent current stability in terms of thermal variations of the LDMOS guarantees a robust operation in any topology of DVB-T signal amplifiers. Otherwise, progressively uncontrolled heat dissipation enhancement on the LDMOS case can degrade the amplifier’s crucial parameters in regards to the gain, linearity, and RF stability, resulting in dysfunctional operation or a total destruction of the unit. This paper presents one more sophisticated approach from the traditional biasing circuits used so far in LDMOS DVB-T amplifiers. It utilizes a microprocessor control technology, providing stability in topologies where IDQ must be perfectly accurate.Keywords: LDMOS, amplifier, back-off, bias circuit
Procedia PDF Downloads 339481 Do Industry Expert Audit Engagement Partners Earn Fee Premiums? Evidence from Labor Usage and the Hourly Charge Rate
Authors: Gil Bae, Seung Uk Choi, Jae Eun Lee, Joon Hwa Rho
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Using proprietary engagement partner identity information for the Big 4 audit firms in Korea over the 2001-2011 period, we find that expert engagement partners obtain significantly higher total compensation than do non-expert partners. Importantly, we also find that expert partners increase the number of audit hours compared to their non-expert counterparts. The hourly billing rate, calculated as total fees divided by total audit hours, of expert partners is not higher than that of non-expert partners, indicating that there is no expert partner premium reflected in the hourly rate. This finding suggests that the increase in total audit fees is attributable mainly to the increase in the quantity of audit hours that expert partners work, not from the higher fee per hour. The results are not attributable to auditor selection bias.Keywords: industry expert partners, expert premiums, audit hours, hourly charge rate
Procedia PDF Downloads 304480 Three-Dimensional Fluid-Structure-Thermal Coupling Dynamics Simulation Model of a Gas-Filled Fluid-Resistance Damper and Experimental Verification
Authors: Wenxue Xu
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Fluid resistance damper is an important damping element to attenuate vehicle vibration. It converts vibration energy into thermal energy dissipation through oil throttling. It is a typical fluid-solid-heat coupling problem. A complete three-dimensional flow-structure-thermal coupling dynamics simulation model of a gas-filled fluid-resistance damper was established. The flow-condition-based interpolation (FCBI) method and direct coupling calculation method, the unit's FCBI-C fluid numerical analysis method and iterative coupling calculation method are used to achieve the damper dynamic response of the piston rod under sinusoidal excitation; the air chamber inflation pressure, spring compression characteristics, constant flow passage cross-sectional area and oil parameters, etc. The system parameters, excitation frequency, and amplitude and other excitation parameters are analyzed and compared in detail for the effects of differential pressure characteristics, velocity characteristics, flow characteristics and dynamic response of valve opening, floating piston response and piston rod output force characteristics. Experiments were carried out on some simulation analysis conditions. The results show that the node-based FCBI (flow-condition-based interpolation) fluid numerical analysis method and direct coupling calculation method can better guarantee the conservation of flow field calculation, and the calculation step is larger, but the memory is also larger; if the chamber inflation pressure is too low, the damper will become cavitation. The inflation pressure will cause the speed characteristic hysteresis to increase, and the sealing requirements are too strict. The spring compression characteristics have a great influence on the damping characteristics of the damper, and reasonable damping characteristic needs to properly design the spring compression characteristics; the larger the cross-sectional area of the constant flow channel, the smaller the maximum output force, but the more stable when the valve plate is opening.Keywords: damper, fluid-structure-thermal coupling, heat generation, heat transfer
Procedia PDF Downloads 144479 Application of Complete Ensemble Empirical Mode Decomposition with Adaptive Noise and Multipoint Optimal Minimum Entropy Deconvolution in Railway Bearings Fault Diagnosis
Authors: Yao Cheng, Weihua Zhang
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Although the measured vibration signal contains rich information on machine health conditions, the white noise interferences and the discrete harmonic coming from blade, shaft and mash make the fault diagnosis of rolling element bearings difficult. In order to overcome the interferences of useless signals, a new fault diagnosis method combining Complete Ensemble Empirical Mode Decomposition with adaptive noise (CEEMDAN) and Multipoint Optimal Minimum Entropy Deconvolution (MOMED) is proposed for the fault diagnosis of high-speed train bearings. Firstly, the CEEMDAN technique is applied to adaptively decompose the raw vibration signal into a series of finite intrinsic mode functions (IMFs) and a residue. Compared with Ensemble Empirical Mode Decomposition (EEMD), the CEEMDAN can provide an exact reconstruction of the original signal and a better spectral separation of the modes, which improves the accuracy of fault diagnosis. An effective sensitivity index based on the Pearson's correlation coefficients between IMFs and raw signal is adopted to select sensitive IMFs that contain bearing fault information. The composite signal of the sensitive IMFs is applied to further analysis of fault identification. Next, for propose of identifying the fault information precisely, the MOMED is utilized to enhance the periodic impulses in composite signal. As a non-iterative method, the MOMED has better deconvolution performance than the classical deconvolution methods such Minimum Entropy Deconvolution (MED) and Maximum Correlated Kurtosis Deconvolution (MCKD). Third, the envelope spectrum analysis is applied to detect the existence of bearing fault. The simulated bearing fault signals with white noise and discrete harmonic interferences are used to validate the effectiveness of the proposed method. Finally, the superiorities of the proposed method are further demonstrated by high-speed train bearing fault datasets measured from test rig. The analysis results indicate that the proposed method has strong practicability.Keywords: bearing, complete ensemble empirical mode decomposition with adaptive noise, fault diagnosis, multipoint optimal minimum entropy deconvolution
Procedia PDF Downloads 374478 Implemented Cascade with Feed Forward by Enthalpy Balance Superheated Steam Temperature Control for a Boiler with Distributed Control System
Authors: Kanpop Saion, Sakreya Chitwong
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Control of superheated steam temperature in the steam generation is essential for the efficiency safety and increment age of the boiler. Conventional cascade PID temperature control in the super heater is known to be efficient to compensate disturbance. However, the complex of thermal power plant due to nonlinearity, load disturbance and time delay of steam of superheater system is bigger than other control systems. The cascade loop with feed forward steam temperature control with energy balance compensator using thermodynamic model has been used for the compensation the complex structure of superheater. In order to improve the performance of steam temperature control. The experiment is implemented for 100% load steady and load changing state. The cascade with feed forward with energy balance steam temperature control has stabilized the system as well.Keywords: cascade with feed forward, boiler, superheated steam temperature control, enthalpy balance
Procedia PDF Downloads 307477 An Empirical Analysis of HRM in Different Pharmaceutical Departments of Different Pharmaceutical Industries in Pakistan
Authors: Faisal Ali, Mansoor Shuakat, Cui Lirong, Rabia Riasat
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HR is a department that enhances the power of employee performance in regard with their services, and to make the organization strategic objectives. The main concern of HR department is to organize people, focus on policies and their system. The empirical study shows the relationship between HRM (Human Resource Management practices) and their Job Satisfaction. The Hypothesis is testing on a sample of overall 320 employees of 5 different Pharmaceutical departments of different organizations in Pakistan. The important thing as Relationship of Job satisfaction with HR Practices, Impact on Job Satisfaction with HR Practices, Participation of Staff of Different Departments, HR Practices effects the Job satisfaction, Recruitment or Hiring and Selection effects the Job satisfaction, Training and Development, Performance and Appraisals, Compensation affects the Job satisfaction , and Industrial Relationships affects the Job satisfaction. After finishing all data analysis, the conclusion is that lots of Job related activities raise the confidence of Job satisfaction of employees with their salary and other benefits. Implications of HR practices discussed, Limitations, and future research study also offered write the main conclusion for your paper.Keywords: HRM, HR practices, job satisfaction, TQM
Procedia PDF Downloads 368476 Good Marketing is an Important Factor for the Success of the Institution
Authors: Maamar Moumena
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the Follower of the movement of international competition finds that the success of Japanese companies to break into global markets and win a competitive edge and meet the challenges of this competition, due primarily to the adoption of these companies to the modern concept of marketing, and possession of sophisticated marketing systems, with a focus on pricing policy. The institution's ability to produce goods and services be limited unless accompanied by an effective marketing effort. So the satisfaction of the consumer needs efficiently and effectiveness are unwarranted economic and social presence in the market, and ensure the continuity and achieve their goals, and this can only be achieved through marketing activity, where he activity facet which translates the output of the institution and its presence in the form of financial compensation, and that the inclusion of and marketing function within the functions of the institution and awarded each of gravity reflects the extent of their importance in the conduct of the future of the institution, and depending on excellence in performance and a good application of the basic concepts of marketing and primarily make the consumer focus of attention, so the pleasing of the consumer and earn his allegiance reflects the success of an organization.Keywords: competition, marketing, institution, consumer
Procedia PDF Downloads 282475 Exploiting Fast Independent Component Analysis Based Algorithm for Equalization of Impaired Baseband Received Signal
Authors: Muhammad Umair, Syed Qasim Gilani
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A technique using Independent Component Analysis (ICA) for blind receiver signal processing is investigated. The problem of the receiver signal processing is viewed as of signal equalization and implementation imperfections compensation. Based on this, a model similar to a general ICA problem is developed for the received signal. Then, the use of ICA technique for blind signal equalization in the time domain is presented. The equalization is regarded as a signal separation problem, since the desired signal is separated from interference terms. This problem is addressed in the paper by over-sampling of the received signal. By using ICA for equalization, besides channel equalization, other transmission imperfections such as Direct current (DC) bias offset, carrier phase and In phase Quadrature phase imbalance will also be corrected. Simulation results for a system using 16-Quadraure Amplitude Modulation(QAM) are presented to show the performance of the proposed scheme.Keywords: blind equalization, blind signal separation, equalization, independent component analysis, transmission impairments, QAM receiver
Procedia PDF Downloads 214474 Negative Environmental Impacts on Marine Seismic Survey Activities
Authors: Katherine Del Carmen Camacho Zorogastua, Victor Hugo Gallo Ramos, Jhon Walter Gomez Lora
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Marine hydrocarbon exploration (oil and natural gas) activities are developed using 2D, 3D and 4D seismic prospecting techniques where sound waves are directed from a seismic vessel emitted every few seconds depending on the variety of air compressors, which cross the layers of rock at the bottom of the sea and are reflected to the surface of the water. Hydrophones receive and record the reflected energy signals for cross-sectional mapping of the lithological profile in order to identify possible areas where hydrocarbon deposits can be formed. However, they produce several significant negative environmental impacts on the marine ecosystem and in the social and economic sectors. Therefore, the objective of the research is to publicize the negative impacts and environmental measures that must be carried out during the development of these activities to prevent and mitigate water quality, the population involved (fishermen) and the marine biota (e.g., Cetaceans, fish) that are the most vulnerable. The research contains technical environmental aspects based on bibliographic sources of environmental studies approved by the Peruvian authority, research articles, undergraduate and postgraduate theses, books, guides, and manuals from Spain, Australia, Canada, Brazil, and Mexico. It describes the negative impacts on the environment and population (fishing sector), environmental prevention, mitigation, recovery and compensation measures that must be properly implemented and the cases of global sea species stranding, for which international experiences from Spain, Madagascar, Mexico, Ecuador, Uruguay, and Peru were referenced. Negative impacts on marine fauna, seawater quality, and the socioeconomic sector (fishermen) were identified. Omission or inadequate biological monitoring in mammals could alter their ability to communicate, feed, and displacement resulting in their stranding and death. In fish, they cause deadly damage to physical-physiological type and in their behavior. Inadequate wastewater treatment and waste management could increase the organic load and oily waste on seawater quality in violation of marine flora and fauna. The possible estrangement of marine resources (fish) affects the economic sector as they carry out their fishing activity for consumption or sale. Finally, it is concluded from the experiences gathered from Spain, Madagascar, Mexico, Ecuador, Uruguay, and Peru that there is a cause and effect relationship between the inadequate development of seismic exploration activities (cause) and marine species strandings (effect) since over the years, stranded or dead marine mammals have been detected on the shores of the sea in areas of seismic acquisition of hydrocarbons. In this regard, it is recommended to establish technical procedures, guidelines, and protocols for the monitoring of marine species in order to contribute to the conservation of hydrobiological resources.Keywords: 3D seismic prospecting, cetaceans, significant environmental impacts, prevention, mitigation, recovery, environmental compensation
Procedia PDF Downloads 185473 Ultrasonic Micro Injection Molding: Manufacturing of Micro Plates of Biomaterials
Authors: Ariadna Manresa, Ines Ferrer
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Introduction: Ultrasonic moulding process (USM) is a recent injection technology used to manufacture micro components. It is able to melt small amounts of material so the waste of material is certainly reduced comparing to microinjection molding. This is an important advantage when the materials are expensive like medical biopolymers. Micro-scaled components are involved in a variety of uses, such as biomedical applications. It is required replication fidelity so it is important to stabilize the process and minimize the variability of the responses. The aim of this research is to investigate the influence of the main process parameters on the filling behaviour, the dimensional accuracy and the cavity pressure when a micro-plate is manufactured by biomaterials such as PLA and PCL. Methodology or Experimental Procedure: The specimens are manufactured using a Sonorus 1G Ultrasound Micro Molding Machine. The used geometry is a rectangular micro-plate of 15x5mm and 1mm of thickness. The materials used for the investigation are PLA and PCL due to biocompatible and degradation properties. The experimentation is divided into two phases. Firstly, the influence of process parameters (vibration amplitude, sonotrodo velocity, ultrasound time and compaction force) on filling behavior is analysed, in Phase 1. Next, when filling cavity is assured, the influence of both cooling time and force compaction on the cavity pressure, part temperature and dimensional accuracy is instigated, which is done in Phase. Results and Discussion: Filling behavior depends on sonotrodo velocity and vibration amplitude. When the ultrasonic time is higher, more ultrasonic energy is applied and the polymer temperature increases. Depending on the cooling time, it is possible that when mold is opened, the micro-plate temperature is too warm. Consequently, the polymer relieve its stored internal energy (ultrasonic and thermal) expanding through the easier direction. This fact is reflected on dimensional accuracy, causing micro-plates thicker than the mold. It has also been observed the most important fact that affects cavity pressure is the compaction configuration during the manufacturing cycle. Conclusions: This research demonstrated the influence of process parameters on the final micro-plated manufactured. Future works will be focused in manufacturing other geometries and analysing the mechanical properties of the specimens.Keywords: biomaterial, biopolymer, micro injection molding, ultrasound
Procedia PDF Downloads 284472 Vibration Analysis of Pendulum in a Viscous Fluid by Analytical Methods
Authors: Arash Jafari, Mehdi Taghaddosi, Azin Parvin
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In this study, a vibrational differential equation governing on swinging single-degree-of-freedom pendulum in a viscous fluid has been investigated. The damping process is characterized according to two different regimes: at first, damping in stationary viscous fluid, in the second, damping in flowing viscous fluid with constant velocity. Our purpose is to enhance the ability of solving the mentioned nonlinear differential equation with a simple and innovative approach. Comparisons are made between new method and Numerical Method (rkf45). The results show that this method is very effective and simple and can be applied for other nonlinear problems.Keywords: oscillating systems, angular frequency and damping ratio, pendulum at fluid, locus of maximum
Procedia PDF Downloads 337471 Damping Function and Dynamic Simulation of GUPFC Using IC-HS Algorithm
Authors: Galu Papy Yuma
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This paper presents a new dynamic simulation of a power system consisting of four machines equipped with the Generalized Unified Power Flow Controller (GUPFC) to improve power system stability. The dynamic simulation of the GUPFC consists of one shunt converter and two series converters based on voltage source converter, and DC link capacitor installed in the power system. MATLAB/Simulink is used to arrange the dynamic simulation of the GUPFC, where the power system is simulated in order to investigate the impact of the controller on power system oscillation damping and to show the simulation program reliability. The Improved Chaotic- Harmony Search (IC-HS) Algorithm is used to provide the parameter controller in order to lead-lag compensation design. The results obtained by simulation show that the power system with four machines is suitable for stability analysis. The use of GUPFC and IC-HS Algorithm provides the excellent capability in fast damping of power system oscillations and improve greatly the dynamic stability of the power system.Keywords: GUPFC, IC-HS algorithm, Matlab/Simulink, damping oscillation
Procedia PDF Downloads 448470 Failure Analysis of a 304 Stainless Steel Flange Crack at Pipeline Transportation of Ethylene
Authors: Parisa Hasanpour, Bahram Borooghani, Vahid Asadi
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In the current research, a catastrophic failure of a 304 stainless steel flange at pipeline transportation of ethylene in a petrochemical refinery was studied. Cracking was found in the flange after about 78840h service. Through the chemical analysis, tensile tests in addition to microstructural analysis such as optical microscopy and Scanning Electron Microscopy (SEM) on the failed part, it found that the fatigue was responsible for the fracture of the flange, which originated from bumps and depressions on the outer surface and propagated by vibration caused by the working condition.Keywords: failure analysis, 304 stainless steel, fatigue, flange, petrochemical refinery
Procedia PDF Downloads 71469 Nonlinear Free Vibrations of Functionally Graded Cylindrical Shells
Authors: Alexandra Andrade Brandão Soares, Paulo Batista Gonçalves
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Using a modal expansion that satisfies the boundary and continuity conditions and expresses the modal couplings characteristic of cylindrical shells in the nonlinear regime, the equations of motion are discretized using the Galerkin method. The resulting algebraic equations are solved by the Newton-Raphson method, thus obtaining the nonlinear frequency-amplitude relation. Finally, a parametric analysis is conducted to study the influence of the geometry of the shell, the gradient of the functional material and vibration modes on the degree and type of nonlinearity of the cylindrical shell, which is the main contribution of this research work.Keywords: cylindrical shells, dynamics, functionally graded material, nonlinear vibrations
Procedia PDF Downloads 65468 FDI, Environmental Regulations and Innovation Performance of Chinese Enterprises
Authors: Yan Chen, Hongbing Li, Ruirui Zhai
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Innovation driven and innovation in the process of new-type urbanization is a major strategic choice for the introduction of foreign capital and the process of economic development. This research investigates the effect of urbanization, FDI and environmental regulations on innovation performance of enterprises, based on Chinese Industrial Statistics Database of 2004 to 2007 and data at province-level. It is found that the FDI from U.S. and environmental regulations will hinder the creativity of Chinese industry through reducing the R&D of them. However, the FDI from U.S. enhances the ability of domestic enterprises to attain “compensation from innovation” following the environmental regulations. Meanwhile, we confirm that environmental regulation can contribute to the innovation spillover of FDI from U.S. Furthermore, the channel of effect is discussed. In addition, FDI from EU and Japan are further examined. Unlike the FDI from U.S., the FDI from EU and Japan both have the positive innovation spillover effect, but through the same channel referred above which exist in FDI. Further analysis based on "innovation-driven effect" of urbanization is developed, and it is found that urbanization has an innovation-driven effect on environmental regulation and FDI spillover. The regulation of FDI from the United States and the European Union outperforms the FDI from Japan at a restrained degree.Keywords: environmental regulations, FDI, innovation-driven, innovation performance
Procedia PDF Downloads 442467 Efficient Motion Estimation by Fast Three Step Search Algorithm
Authors: S. M. Kulkarni, D. S. Bormane, S. L. Nalbalwar
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The rapid development in the technology have dramatic impact on the medical health care field. Medical data base obtained with latest machines like CT Machine, MRI scanner requires large amount of memory storage and also it requires large bandwidth for transmission of data in telemedicine applications. Thus, there is need for video compression. As the database of medical images contain number of frames (slices), hence while coding of these images there is need of motion estimation. Motion estimation finds out movement of objects in an image sequence and gets motion vectors which represents estimated motion of object in the frame. In order to reduce temporal redundancy between successive frames of video sequence, motion compensation is preformed. In this paper three step search (TSS) block matching algorithm is implemented on different types of video sequences. It is shown that three step search algorithm produces better quality performance and less computational time compared with exhaustive full search algorithm.Keywords: block matching, exhaustive search motion estimation, three step search, video compression
Procedia PDF Downloads 491466 A Mixed Finite Element Formulation for Functionally Graded Micro-Beam Resting on Two-Parameter Elastic Foundation
Authors: Cagri Mollamahmutoglu, Aykut Levent, Ali Mercan
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Micro-beams are one of the most common components of Nano-Electromechanical Systems (NEMS) and Micro Electromechanical Systems (MEMS). For this reason, static bending, buckling, and free vibration analysis of micro-beams have been the subject of many studies. In addition, micro-beams restrained with elastic type foundations have been of particular interest. In the analysis of microstructures, closed-form solutions are proposed when available, but most of the time solutions are based on numerical methods due to the complex nature of the resulting differential equations. Thus, a robust and efficient solution method has great importance. In this study, a mixed finite element formulation is obtained for a functionally graded Timoshenko micro-beam resting on two-parameter elastic foundation. In the formulation modified couple stress theory is utilized for the micro-scale effects. The equation of motion and boundary conditions are derived according to Hamilton’s principle. A functional, derived through a scientific procedure based on Gateaux Differential, is proposed for the bending and buckling analysis which is equivalent to the governing equations and boundary conditions. Most important advantage of the formulation is that the mixed finite element formulation allows usage of C₀ type continuous shape functions. Thus shear-locking is avoided in a built-in manner. Also, element matrices are sparsely populated and can be easily calculated with closed-form integration. In this framework results concerning the effects of micro-scale length parameter, power-law parameter, aspect ratio and coefficients of partially or fully continuous elastic foundation over the static bending, buckling, and free vibration response of FG-micro-beam under various boundary conditions are presented and compared with existing literature. Performance characteristics of the presented formulation were evaluated concerning other numerical methods such as generalized differential quadrature method (GDQM). It is found that with less computational burden similar convergence characteristics were obtained. Moreover, formulation also includes a direct calculation of the micro-scale related contributions to the structural response as well.Keywords: micro-beam, functionally graded materials, two-paramater elastic foundation, mixed finite element method
Procedia PDF Downloads 160465 Physicochemical Characterization of Mercerized Cellulose-Supported Nickel-Oxide
Authors: Sherif M. A. S. Keshk, Hisham S. M. Abd-Rabboh, Mohamed S. Hamdy, Ibrahim H. A. Badr
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Microwave radiation was applied to synthesize nanoparticles of nickel oxide supported on pretreated cellulose with metal acetate in the presence of NaOH. Optimization, in terms of irradiation time and metal concentration, was investigated. FT-IR spectrum of cellulose/NiO spectrum shows a band at 445 cm^-1 that is related to the Ni–O stretching vibration of NiO6 octahedral in the cubic NiO structure. cellulose/NiO showed similar XRD pattern of cellulose I and exhibited sharpened reflection peak at 2q = 29.8°, corresponding to (111) plane of NiO, with two weak broad peaks at 48.5°, and 49.2°, representing (222) planes of NiO. XPS spectrum of mercerized cellulose/NiO composite showed did not show any peaks corresponding to Na ion.Keywords: cellulose, mercerized cellulose, cellulose/zinc and nickeloxides composite, FTIR, XRD, XPS, SEM, Raman spectrum
Procedia PDF Downloads 442464 The Role of Law Corruption and Culture in Investment Fund Manager Fees
Authors: Samir Assal
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This paper considers an international sample of venture capital and private equity funds to assess the role of law, corruption and culture in setting fund manager fees in terms of their fixed management fees, carried interest performance fees, clawbacks of fees and cash versus share distributions of fees. The data highlight a role of legal conditions in shaping fees paid to fund managers. In countries with better legal conditions, fixed fees are lower, carried interest fees are higher, clawbacks are less likely, and share distributions are more likely. These findings suggest legal conditions help to align the interests of managers and shareholders. More specifically, we examine which element of legal conditions matter most, and discover that corruption levels play a pronounced role in shaping fund manager fee contracts. We also show that cultural forces such as Hofstede’s measures of power distance and uncertainty avoidance likewise play a role in influencing fees.Keywords: managerial compensation, incentive contracts, private equity, law and finance
Procedia PDF Downloads 309463 Cross Coupling Sliding Mode Synchronization Control of Dual-Driving Feed System
Authors: Hong Lu, Wei Fan, Yongquan Zhang, Junbo Zhang
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A cross coupling sliding synchronization control strategy is proposed for the dual-driving feed system. This technology will minimize the position error oscillation and achieve the precise synchronization performance in the high speed and high precision drive system, especially some high speed and high precision machine. Moreover, a cross coupling compensation matrix is provided to offset the mismatched disturbance and the disturbance observer is established to eliminate the chattering phenomenon. Performance comparisons of proposed dual-driving cross coupling sliding mode control (CCSMC), normal cross coupling control (CCC) strategy with PID control, and electronic virtual main shaft control (EVMSC) strategy with SMC control are investigated by simulation and a dual-driving control system; the results show the effectiveness of the proposed control scheme.Keywords: cross coupling matrix, dual motors, synchronization control, sliding mode control
Procedia PDF Downloads 365462 Synthesis, Structural and Magnetic Properties of CdFe2O4 Ferrite
Authors: Justice Zakhele Msomi
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Nanoparticles of CdFe2O4 with particle size of about 10 nm have been synthesized by high energy ball milling and co-precipitation processes. The synthesis route appears to have some effects on the properties. The compounds have been characterized by X-ray diffraction, Fourier Transform Infrared (FTIR), transmission electron microscopy (TEM), Mössbauer and magnetization measurements. The XRD pattern of CdFe2O4 provides information about single-phase formation of spinel structure with cubic symmetry. The FTIR measurements between 400 and 4000 cm-1 indicate intrinsic cation vibration of the spinel structure. The Mössbauer spectra were recorded at 4 K and 300 K. The hyperfine fields appear to be highly sensitive on particle size. The evolution of the properties as a function of particle size is also presented.Keywords: ferrite, nanoparticles, magnetization, Mössbauer
Procedia PDF Downloads 403461 Layer-By-Layer Deposition of Poly (Amidoamine) and Poly (Acrylic Acid) on Grafted-Polylactide Nonwoven with Different Surface Charge
Authors: Sima Shakoorjavan, Mahdieh Eskafi, Dawid Stawski, Somaye Akbari
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In this study, poly (amidoamine) dendritic material (PAMAM) and poly (acrylic acid) (PAA) as polycation and polyanion were deposited on surface charged polylactide (PLA) nonwoven to study the relationship of dye absorption capacity of layered-PLA with the number of deposited layers. To produce negatively charged-PLA, acrylic acid (AA) was grafted on the PLA surface (PLA-g-AA) through a chemical redox reaction with the strong oxidizing agent. Spectroscopy analysis, water contact measurement, and FTIR-ATR analysis confirm the successful grafting of AA on the PLA surface through the chemical redox reaction method. In detail, an increase in dye absorption percentage by 19% and immediate absorption of water droplets ensured hydrophilicity of PLA-g-AA surface; and the presence of new carbonyl bond at 1530 cm-¹ and a wide peak of hydroxyl between 3680-3130 cm-¹ confirm AA grafting. In addition, PLA as linear polyester can undergo aminolysis, which is the cleavage of ester bonds and replacement with amid bonds when exposed to an aminolysis agent. Therefore, to produce positively charged PLA, PAMAM as amine-terminated dendritic material was introduced to PLA molecular chains at different conditions; (1) at 60 C for 0.5, 1, 1.5, 2 hours of aminolysis and (2) at room temperature (RT) for 1, 2, 3, and 4 hours of aminolysis. Weight changes and spectrophotometer measurements showed a maximum in weight gain graph and K/S value curve indicating the highest PAMAM attachment at 60 C for 1 hour and RT for 2 hours which is considered as an optimum condition. Also, the emerging new peak around 1650 cm-1 corresponding to N-H bending vibration and double wide peak at around 3670-3170 cm-1 corresponding to N-H stretching vibration confirm PAMAM attachment in selected optimum condition. In the following, regarding the initial surface charge of grafted-PLA, lbl deposition was performed and started with PAA or PAMAM. FTIR-ATR results confirm chemical changes in samples due to deposition of the first layer (PAA or PAMAM). Generally, spectroscopy analysis indicated that an increase in layer number costed dye absorption capacity. It can be due to the partial deposition of a new layer on the previously deposited layer; therefore, the available PAMAM at the first layer is more than the third layer. In detail, in the case of layer-PLA starting lbl with negatively charged, having PAMAM as the first top layer (PLA-g-AA/PAMAM) showed the highest dye absorption of both cationic and anionic model dye.Keywords: surface modification, layer-by-layer technique, dendritic materials, PAMAM, dye absorption capacity, PLA nonwoven
Procedia PDF Downloads 84460 Numerical Simulation and Optimal Control in Gas Dynamic Laser GDLs
Authors: Laggoun Chouki
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In this paper we present the design and mechanisms of the physics process and discuss the performances of continuous gas laser dynamics, based on molecules N2(v=1)→C02(001)(v=3). The main objectives of work in this area are, obtaining the high laser energies in short time durations needed for the feasibility studies the physical principles that can be used to make laser sources capable of delivering high average powers. We note that, in order to reach both objectives, one has to convert electrical or chemical energy into laser energy, using gaseous media. The process generating the wave excited, on the basis of the excited level vibration, Theoretical predictions are compared with experimental results. The feasibility and effectiveness of the proposed method is demonstrated by computer simulation.Keywords: modelling, lasers, gas, numerical, nozzle
Procedia PDF Downloads 82459 The Cracks Propagation Monitoring of a Cantilever Beam Using Modal Analysis
Authors: Morteza Raki, Abolghasem Zabihollah, Omid Askari
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Cantilever beam is a simplified sample of a lot of mechanical components used in a wide range of applications, including many industries such as gas turbine blade. Due to the nature of the operating conditions, beams are subject to variety of damages especially crack propagates. Crack propagation may lead to catastrophic failure during operation. Therefore, online detection of crack presence and its propagation is very important and may reduce possible significant cost of the whole system failure. This paper aims to investigate the effect of cracks presence and crack propagation on one end fixed beam`s vibration. A finite element model will be developed for the blade in which the modal response of the structure with and without crack will be studied.Keywords: blade, crack propagation, health monitoring, modal analysis
Procedia PDF Downloads 344458 Identification of Transformer Core Vibrations and the Effect of Third Harmonic in the Electricity Grid
Authors: Setareh Gorji Ghalamestani, Lieven Vandevelde, Jan Melkebeek
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In this work, an experimental technique is applied for the measurements of the vibrations and deformation of a test transformer core. Since the grid voltage contains some higher harmonics, in addition to a purely sinusoidal magnetisation of the core the presence of third harmonic is also studied. The vibrations of the transformer core for points as well as the surface scan of the leg show more deformation in the corners of the leg than the middle of the leg. The influence of the higher harmonic of the magnetisation on the core deformation is also more significant in the corners of the leg. The core deformation shape under a sinusoidal magnetisation with a higher harmonic is more wavy and fluctuating than that under a purely sinusoidal magnetisation.Keywords: vibrations and noise, transformer, vibration measurements, laser vibrometer, higher harmonic
Procedia PDF Downloads 368457 Experimental Analysis of Tuned Liquid Damper (TLD) with Embossments Subject to Random Excitation
Authors: Mohamad Saberi, Arash Sohrabi
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Tuned liquid damper is one the passive structural control ways which has been used since mid-1980 decade for seismic control in civil engineering. This system is made of one or many tanks filled with fluid, mostly water that installed on top of the high raised structure and used to prevent structure vibration. In this article we will show how to make seismic table contain TLD system and analysis the result of using this system in our structure. Results imply that when frequency ratio approaches 1 this system can perform its best in both dissipate energy and increasing structural damping. And also results of these serial experiments are proved compatible with Hunzer linear theory behaviour.Keywords: TLD, seismic table, structural system, Hunzer linear behaviour
Procedia PDF Downloads 378456 Musculoskeletal Disorders among Employees of an Assembly Industrial Workshop: Biomechanical Constrain’s Semi-Quantitative Analysis
Authors: Lamia Bouzgarrou, Amira Omrane, Haithem Kalel, Salma Kammoun
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Background: During recent decades, mechanical and electrical industrial sector has greatly expanded with a significant employability potential. However, this sector faces the increasing prevalence of musculoskeletal disorders with heavy consequences associated with direct and indirect costs. Objective: The current intervention was motivated by large musculoskeletal upper limbs and back disorders frequency among the operators of an assembly workshop in a leader company specialized in sanitary equipment and water and gas connections. We aimed to identify biomechanical constraints among these operators through activity and biomechanical exposures semi-quantitative analysis based on video recordings and MUSKA-TMS software. Methods: We conducted, open observations and exploratory interviews at first, in order to overall understand work situation. Then, we analyzed operator’s activity through systematic observations and interviews. Finally, we conducted a semi-quantitative biomechanical constraints analysis with MUSKA-TMS software after representative activity period video recording. The assessment of biomechanical constrains was based on different criteria; biomechanical characteristics (work positions), aggravating factor (cold, vibration, stress, etc.) and exposure time (duration and frequency of solicitations, recovery phase); with a synthetic score of risk level variable from 1 to 4 (1: low risk of developing MSD and 4: high risk). Results: Semi-quantitative analysis objective many elementary operations with higher biomechanical constrains like high repetitiveness, insufficient recovery time and constraining angulation of shoulders, wrists and cervical spine. Among these risky elementary operations we sited the assembly of sleeve with the body, the assembly of axis, and the control on testing table of gas valves. Transformation of work situations were recommended, covering both the redevelopment of industrial areas and the integration of new tools and equipment of mechanical handling that reduces operator exposure to vibration. Conclusion: Musculoskeletal disorders are complex and costly disorders. Moreover, an approach centered on the observation of the work can promote the interdisciplinary dialogue and exchange between actors with the objective to maximize the performance of a company and improve the quality of life of operators.Keywords: musculoskeletal disorders, biomechanical constrains, semi-quantitative analysis, ergonomics
Procedia PDF Downloads 161455 The Usefulness of Financial Certification in Taiwan
Authors: Chih-Mei Wang, Jon-Chao Hong, Jian-Hong Ye, Jing-Yun Fan, Chiao-Fei Lin
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The value of a certificate is to implement the criteria for evaluating work ability. Some professional certificates may make people feel good, but they are not useful in the workplace. To address this issue, this study is based on the expectancy-value model to take financial certificates as an example to explore how participants perceived the value of obtaining certification related to their usage perception of career promotion and salary increase. A total of 339 valid samples were subjected to confirmatory factor analysis and structural equation modeling; the results showed that the number of professional certificates was not significantly correlated with career promotion, but the number of professional certificates is negatively related to salary and benefits (S&B), while career promotion and S&B were positively related to job performance. The results show that the number of professional certificates does not play a significant role in the expectancy-value model. Therefore, professional certifications related to a basic level of finance was not expected to obtain in Taiwan's financial industry, and it is important to study the usefulness of some other certificates in other competitive industry.Keywords: career promotion, certificate, compensation and benefits, goal-directed behaviors, Job performance
Procedia PDF Downloads 192454 Hydraulic Resources Management under Imperfect Competition with Thermal Plants in the Wholesale Electricity Market
Authors: Abdessalem Abbassi, Ahlem Dakhlaoui, Lota D. Tamini
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In this paper, we analyze infinite discrete-time games between hydraulic and thermal power operators in the wholesale electricity market under Cournot competition. We consider a deregulated electrical industry where certain demand is satisfied by hydraulic and thermal technologies. The hydraulic operator decides the production in each season of each period that maximizes the sum of expected profits from power generation with respect to the stochastic dynamic constraint on the water stored in the dam, the environmental constraint and the non-negative output constraint. In contrast, the thermal plant is operated with quadratic cost function, with respect to the capacity production constraint and the non-negativity output constraint. We show that under imperfect competition, the hydraulic operator has a strategic storage of water in the peak season. Then, we quantify the strategic inter-annual and intra-annual water transfer and compare the numerical results. Finally, we show that the thermal operator can restrict the hydraulic output without compensation.Keywords: asymmetric risk aversion, electricity wholesale market, hydropower dams, imperfect competition
Procedia PDF Downloads 359