http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2013 , Hindawi Publishing Corporation . All rights reserved. Thu, 23 May 2013 18:51:29 +0000 http://www.hindawi.com/journals/ame/2013/943528/ This paper presents a new kind of shock absorber, hydraulic electromagnetic shock absorber (HESA), which can not only isolate vibration but also recover energy from vibration of vehicles. The energy recovery scheme is put forward, and the HESA prototype as well as the bench is trial manufactured. The damping characteristic of the HESA prototype is tested, and its performance is good under low cracking pressure and small excitation amplitude without taking the requirement that damping force in compression stroke is greater than that in extension stroke into account. The energy-regenerative characteristic of the HESA prototype is investigated, and it can recover energy about 200 watts in 10 Hz-3 mm excitation. However, the energy recovery efficiency is only 16.6%, and the rectifying efficiency of the hydraulic rectifier decreases with the excitation frequency increase, which eventually leads to a reduction in energy recovery efficiency. The linear loss of oil is analyzed theoretically, and the wasted power of pipeline is found to account for 1/3 of the total power. It can be seen from the mathematical model of linear loss that this energy loss can be decreased effectively by increasing the inner diameter of pipeline. Zhigang Fang, Xuexun Guo, Lin Xu, and Han Zhang Copyright © 2013 Zhigang Fang et al. All rights reserved. Thu, 23 May 2013 18:50:22 +0000 http://www.hindawi.com/journals/ame/2013/797183/ Belt conveyors are the equipment widely used in coal mines and other manufacturing factories, whose main components are a number of idlers. The faults of belt conveyors can directly influence the daily production. In this paper, a fault diagnosis method combining wavelet packet decomposition (WPD) and support vector machine (SVM) is proposed for monitoring belt conveyors with the focus on the detection of idler faults. Since the number of the idlers could be large, one acceleration sensor is applied to gather the vibration signals of several idlers in order to reduce the number of sensors. The vibration signals are decomposed with WPD, and the energy of each frequency band is extracted as the feature. Then, the features are employed to train an SVM to realize the detection of idler faults. The proposed fault diagnosis method is firstly tested on a testbed, and then an online monitoring and fault diagnosis system is designed for belt conveyors. An experiment is also carried out on a belt conveyor in service, and it is verified that the proposed system can locate the position of the faulty idlers with a limited number of sensors, which is important for operating belt conveyors in practices. Wei Li, Zewen Wang, Zhencai Zhu, Gongbo Zhou, and Guoan Chen Copyright © 2013 Wei Li et al. All rights reserved. Mon, 20 May 2013 14:37:19 +0000 http://www.hindawi.com/journals/ame/2013/130750/ Engineering optimization problems usually contain various constraints and mixed integer-discrete-continuous types of design variables. We propose an efficient particle swarm optimization (PSO) algorithm for such problems. First, we transform the constrained optimization problem into an unconstrained problem without introducing problem-dependent or user-defined parameters such as penalty factors or Lagrange multipliers (such parameters are usually required in general optimization algorithms). Then, we extend the above PSO method to handle integer, discrete, and continuous design variables in a simple manner with a high degree of precision. The proposed PSO scheme is fairly simple and therefore easy to implement. To demonstrate the effectiveness of our method, several mechanical design optimization problems are solved, and the numerical results are compared with results reported in the literature. Semin Chun, Young-Tark Kim, and Tae-Hyoung Kim Copyright © 2013 Semin Chun et al. All rights reserved. Mon, 20 May 2013 11:57:19 +0000 http://www.hindawi.com/journals/ame/2013/156430/ A numerical modeling of bubble-driven flow patterns in a glass of champagne has been carried out for three champagne temperatures, by using the finite-volume method by CFD (computational fluid dynamics). In order to define source terms for flow regime and to reproduce accurately the bubble nucleation process responsible for champagne effervescence, specific subroutines for the gaseous phase have been added to the main numerical model. These subroutines allow the modeling of bubbles behavior based on semiempirical formulas relating to bubble diameter, mass transfer, velocity, and drag force. Both ascending bubble dynamics and bubble-driven flow patterns dynamics were examined, respectively, 60 s, 180 s, and 300 s after pouring champagne into the glass. Details and development of the various steps of modeling are presented in this paper, showing that the bubble-driven flow patterns velocities of the liquid phase significantly vary with the champagne temperature. Fabien Beaumont, Catalin Popa, Gérard Liger-Belair, and Guillaume Polidori Copyright © 2013 Fabien Beaumont et al. All rights reserved. Thu, 16 May 2013 18:29:06 +0000 http://www.hindawi.com/journals/ame/2013/325101/ Particle-laden turbulent flows over a backward-facing step were here numerically studied by means of a large-eddy simulation considering two-way coupling between particle and fluid phases. The modification of turbulence by particles was then analyzed based on the predicted results of mean and fluctuating velocities. The influencing factors of particle size and material density were also evaluated. Turbulence modifications are anisotropic and closely dependent on flow status. Stronger modulations were observed in the up-wall shear flow regions. Fluid laden with smaller size, low-density particles showed enhancement of turbulence in the streamwise direction, but this effect was less pronounced in the case of larger low-density particles. Particle dispersions were also investigated for comparison of particle instantaneous distributions in coherent structures. Particle modulations of turbulence were not found to change particle preferential distributions. The conclusions drawn in the present study were useful for further understanding of a two-phase turbulence physical mechanism and establishment of accurate prediction models for engineering applications. Wang Bing, Zhang Hui Qiang, and Wang Xi Lin Copyright © 2013 Wang Bing et al. All rights reserved. Thu, 16 May 2013 12:29:07 +0000 http://www.hindawi.com/journals/ame/2013/747583/ A new ultrasonic motor using bending modes with single foot is proposed in this study. Two groups of PZT elements are clamped between two horns and two ending caps, respectively, by bolts. Two horns are connected by the driving foot in the middle of the motor. Two orthogonal 3rd bending vibrations of the motor are superimposed and generate elliptical movement at the driving foot. The structure and working principle of the proposed motor are introduced. The structure parameters of the motor are obtained via the ANSYS software. A prototype is fabricated and tested using an impedance analyzer and a scanning laser Doppler vibrometer. The maximum mechanical output force and power of the prototype are measured to be 23 N and 2.9 W, respectively. Xiaohui Yang, Qiang Zhang, and Xiangyu Zhou Copyright © 2013 Xiaohui Yang et al. All rights reserved. Wed, 15 May 2013 15:32:14 +0000 http://www.hindawi.com/journals/ame/2013/628490/ Turbulent Taylor-vortex flows over regularly spaced square ribs mounted on a rotating inner cylinder surface were investigated using direct numerical simulations (DNSs) for a Reynolds number of 3200 (based on the inner-wall velocity and the gap width between two cylinders) in an apparatus with an inner-to-outer radius ratio of 0.617, while varying the streamwise interval of the ribs. We examined the flow and pressure fields around each rib, focusing on the recirculation zone, the frictional drag coefficient, and the pressure (form) drag. Our results for the Taylor-Couette flows were compared to DNS for plane Poiseuille flows over ribbed surfaces performed by Leonardi et al. (2003). We determined the qualitative consistency between them with respect to the roughness effect, which depends significantly on the rib interval, but the rate of increase in the flow resistance was remarkably dampened by roughness in the present flows. Taylor vortices remaining over roughened cylinder surfaces were found to induce quick pressure recovery behind each rib, leading to less pressure drag and an enhanced backflow in the recirculation zone. Takahiro Tsukahara, Manabu Ishikawa, and Yasuo Kawaguchi Copyright © 2013 Takahiro Tsukahara et al. All rights reserved. Wed, 15 May 2013 09:18:16 +0000 http://www.hindawi.com/journals/ame/2013/174987/ Five-plunger pumps are widely used in oil field to recover petroleum due to their reliability and relatively low cost. Petroleum production is, to a great extent, dependent upon the running condition of the pumps. Closely monitoring the condition of the pumps and carrying out timely system diagnosis whenever a fault symptom is detected would help to reduce the production downtime and improve overall productivity. In this paper, a rough set approach of mechanical fault diagnosis is proposed to identify the five-plunger pump faults. The details of the approach, together with the basic concepts of the rough sets theory, are presented. The rough classifier is a set of decision rules derived from lower and upper approximations of decision classes. The definitions of these approximations are based on the indiscernibility relation in the set of objects. The spectrum features of vibration signals are abstracted as the attributes of the learning samples. The minimum decision rule set is used to classify technical states of the considered object. The diagnostic investigation is done on data from a five-plunger pump in outdoor conditions on a real industrial object. Results show that the approach can effectively identify the different operating states of the pump. Jiangping Wang Copyright © 2013 Jiangping Wang. All rights reserved. Tue, 14 May 2013 17:21:00 +0000 http://www.hindawi.com/journals/ame/2013/194610/ In recent years, various wood modification technologies have been commercialized as alternatives to the traditional chemical treatments for wood preservation. The high temperature heat treatment of wood is one of these commercially viable and environmentally friendly alternative wood modification technologies. During this treatment, wood is heated to temperatures above 200°C by contacting it with hot gas. The chemical structure of wood changes leading to increased dimensional stability and resistance to microorganisms. Wood darkens making it aesthetically more attractive. However, it loses some of its elasticity. Therefore, the high temperature heat treatment has to be optimized for each species and each technology. The mathematical modeling is an important tool for optimization. It can also be used as a powerful tool for furnace modification and design. A reliable and predictive model was developed to simulate numerically the heat treatment process. Heat treatment experiments were carried out in the prototype furnace of the University of Quebec at Chicoutimi. The model was validated by comparing the predictions with the experimental data. In this paper, the results of the model applied to birch heat treatment are presented. The model predictions are in good agreement with the data. Duygu Kocaefe, Yasar Kocaefe, Ramdane Younsi, Noura Oumarou, and S. Thierry Lekounougou Copyright © 2013 Duygu Kocaefe et al. All rights reserved. Tue, 14 May 2013 15:27:06 +0000 http://www.hindawi.com/journals/ame/2013/798597/ Cutting forces are one of the inherent phenomena and a very significant indicator of the metal cutting process. The work presented in this paper is an investigation of the prediction of these parameters in turning using soft computing techniques. During the experimental research focus is placed on the application of various methods of cooling and lubricating of the cutting zone. On this occasion were used the conventional method of cooling and lubricating, high pressure jet assisted machining, and minimal quantity lubrication technique. The data obtained by experiment are used to create two different models, namely, artificial neural network and adaptive networks based fuzzy inference systems for prediction of cutting forces. Furthermore, both models are compared with the experimental data and results are indicated. Djordje Cica, Branislav Sredanovic, Gordana Lakic-Globocki, and Davorin Kramar Copyright © 2013 Djordje Cica et al. All rights reserved. Sun, 12 May 2013 18:51:49 +0000 http://www.hindawi.com/journals/ame/2013/620592/ The cycle performance of refrigeration cycles depends not only on their configuration, but also on thermodynamic properties of working pairs regularly composed of refrigerant and absorbent. The commonly used working pairs in absorption cycles are aqueous solutions of either lithium bromide water or ammonia water. However, corrosion, crystallization, high working pressure, and toxicity are their major disadvantages in industrial applications. Therefore, seeking more advantageous working pairs with good thermal stability, with minimum corrosion, and without crystallization has become the research focus in the past two decades. Ionic liquids (ILs) are room-temperature melting salts that can remain in the liquid state at near or below room temperature. ILs have attracted considerable attention due to their unique properties, such as negligible vapor pressure, nonflammability, thermal stability, good solubility, low melting points, and staying in the liquid state over a wide temperature range from room temperature to about 300°C. The previously mentioned highly favorable properties of ILs motivated us for carrying out the present research and reviewing the available ILs found in the literature as the working fluids of absorption cycles. Absorption cycles contain absorption heat pumps, absorption chillers, and absorption transformers. Mehrdad Khamooshi, Kiyan Parham, and Ugur Atikol Copyright © 2013 Mehrdad Khamooshi et al. All rights reserved. Sun, 12 May 2013 15:26:03 +0000 http://www.hindawi.com/journals/ame/2013/502051/ In order to improve the reliability of fault diagnosis, total energy growth rate of rolling bearing during run-up is defined and applied to bearing detection. Firstly, an approach of merging short-time Fourier transform (STFT), linear fitting and median filtering is developed to extract the total energy growth rate. Secondly, the relationship between the total energy growth rate and different running conditions is discussed. Thirdly, the total energy growth rate is adopted to diagnose faults as input vector of radial basis function (RBF) neural network. Experiment results show that the total energy growth rate is an effective failure symbol for fault diagnosis of rolling bearing during run-up. Zhongqiu Wang, Zhencai Zhu, Wei Li, Guoan Chen, and Gongbo Zhou Copyright © 2013 Zhongqiu Wang et al. All rights reserved. Sun, 12 May 2013 08:31:45 +0000 http://www.hindawi.com/journals/ame/2013/426767/ The thermal characteristics of an alternating current light-emitting diode (AC LED) chip based on a three-dimensional unsteady numerical simulation are discussed. In this model, the difficulties due to the tiny scale and extra-low aspect ratio of the AC LED microchip geometry are resolved. A time lag between the maximum forward voltage and the highest mean junction temperature is observed. The influence of different input power frequencies on the thermal fields is also investigated for AC LEDs with 600 μm × 600 μm area. A numerical simulation of the junction temperature distributions shows that the AC LED has a better performance under a higher frequency than under a lower frequency. Farn-Shiun Hwu and Hung-Lin Hsieh Copyright © 2013 Farn-Shiun Hwu and Hung-Lin Hsieh. All rights reserved. Thu, 09 May 2013 19:01:58 +0000 http://www.hindawi.com/journals/ame/2013/868240/ We developed a new immersed boundary method which has various advantages, such as accuracy, flexibility, and rapidness combining with the level set method. We numerically demonstrated some typical examples, such as flows around a sphere, an ellipsoid, a flapping ellipsoid, and a windmill. We calculated coefficients of drag in those problems and visualized vortical structures and Powell sound sources for the various Reynolds number and then compared our results with some previous researches. Atsuki Iijima, Tomomitsu Sato, and Toshio Tagawa Copyright © 2013 Atsuki Iijima et al. All rights reserved. Tue, 07 May 2013 10:38:45 +0000 http://www.hindawi.com/journals/ame/2013/493212/ Large eddy simulation of inertial particle dispersion in a turbulent flow over a backward-facing step was performed. The numerical results of both instantaneous particle dispersion and two-phase velocity statistics were in good agreement with the experimental measurements. The analysis of preferential dispersion of inertial particles was then presented by a wavelets analysis method for decomposing the two-phase turbulence signal obtained by numerical simulations, showing that the inertial particle concentration is separation from the Gaussian random distribution with very strong intermittencies. The statistical PDF of vorticity seen by particles shows that the inertial particles tend to accumulate in low vorticity regions where  :  is larger than zero. The concentration distribution of particle preferential dispersion preserves the historical effects. The research conclusions are useful for further understanding the two-phase turbulence physics and establishing accurate engineering prediction models of particle dispersion. Bing Wang, Huiqiang Zhang, and Xilin Wang Copyright © 2013 Bing Wang et al. All rights reserved. Thu, 02 May 2013 11:52:53 +0000 http://www.hindawi.com/journals/ame/2013/126353/ In this study a partially open enclosure with two heat sources is examined to determine the Nusselt number along the hot wall. The first part of the study examines the effect of the Rayleigh number ratio on the Nusselt number. The largest Rayleigh number ratio results in the highest magnitude of the Nusselt number. The second part of the study examines what happens to the Nusselt number along the hot wall as the Rayleigh number ratio for the two blocks is different. This situation can arise when the two blocks have unequal heat source values. The largest Nusselt numbers correspond to the situation when the block along the top wall has a Rayleigh number ratio that is ten times higher than the Rayleigh number ratio for the block along the hot wall. The largest Nusselt number magnitudes can be attributed to the strong vortex in the corner near the hot wall. M. McGarry and James G. Kohl Copyright © 2013 M. McGarry and James G. Kohl. All rights reserved. Thu, 02 May 2013 09:04:09 +0000 http://www.hindawi.com/journals/ame/2013/950765/ A numerical study of the flow and heat transfer on a rotating cylindrical cavity solving the mass, momentum, and energy equations is presented in this work. The study describes the influence of the Prandtl number on flow in critical state on a cavity which contains a cooling fluid. Problem studied includes Prandtl numbers , aspect ratios and Reynolds numbers . Differential equations have been discretised using the finite differences method. The results show a tendency followed by heat transfer as the Reynolds number increases from 300 to 600; in addition, emphasis on the critical values of the Rayleigh number for small Prandtl numbers shows that thermal instability in mixed convection depends on the Prandtl number. Gustavo Urquiza, Laura Castro, Juan García, Miguel Basurto, and Enoc Bogarin Copyright © 2013 Gustavo Urquiza et al. All rights reserved. Thu, 02 May 2013 08:53:37 +0000 http://www.hindawi.com/journals/ame/2013/654396/ As the legislations on the emission and performance of automobiles are being made more stringent, the expected performance of all the subsystems of an internal combustion engine is also becoming crucial. Nowadays the engines are downsized, and their power increased the demand on the air intake system that has increased phenomenally. Hence, an analysis was carried on a typical air filter fitted into the intake system to determine its flow characteristics. In the present investigation, a CAD model of an existing air filter was designed, and CFD analysis was done pertaining to various operating regimes of an internal combustion engine. The numerical results were validated with the experimental data. From the postprocessed result, we can see that there is a deficit in the design of the present filter, as the bottom portion of the filter is preventing the upward movement of air. Hence, the intake passage can be rearranged to provide an upward tangential motion, which can enhance the removal of larger dust and soot particles effectively by the inertial action of air alone. R. Manikantan and E. James Gunasekaran Copyright © 2013 R. Manikantan and E. James Gunasekaran. All rights reserved. Tue, 30 Apr 2013 13:34:54 +0000 http://www.hindawi.com/journals/ame/2013/761840/ Oat hull fibre reinforced polypropylene- (PP-)/polylactide- (PLA-) based biocomposites were fabricated and their process engineering and performances were evaluated. The effect of ethylene propylene-g-maleic anhydride (EP-g-Ma) compatibilizer on mechanical properties of 30 wt% oat hull reinforced PP/PLA (90/10) blend composites was investigated. Thermal degradation parameters of the oat hull fibre were determined using thermogravimetric analysis. The effect of fibre reinforcement on crystallinity of oat hull fibre reinforced PP/PLA composites was studied by differential scanning calorimetry (DSC). Thermomechanical properties of the composites were analyzed by dynamic mechanical analyzer (DMA). The interfacial bonding between the fibre and the matrix was examined using scanning electron microscope (SEM). Significant improvement in tensile strength (40%) and flexural strength (46%) was observed with the addition of EP-g-Ma compatibilizer. DSC analysis of oat hull fibre reinforced composites showed an increase in the crystallization temperature (Tc) due to the nucleation effect of oat hull fibre. DMA results revealed that the storage modulus of PP/PLA/Oat hull fibre composites was higher compared to PP/PLA blend throughout the investigated range of temperature. Jeevan Prasad Reddy, Manjusri Misra, and Amar Mohanty Copyright © 2013 Jeevan Prasad Reddy et al. All rights reserved. Tue, 30 Apr 2013 10:50:50 +0000 http://www.hindawi.com/journals/ame/2013/929236/ Both a numerical and an analytical models were developed to simulate temperature profiles in continuous laminar pipe flow during microwave heating. Fully developed velocity and thermally developing conditions were assumed. The numerical solution was obtained by first solving Maxwell equations and then by coupling them with the energy balance for the flowing fluid. On the other hand, the same problem was solved analytically under the simplifying assumption foreseeing uniform heat generation inside the pipe. With the aim of reducing computational efforts, numerical and analytical results were compared in order to investigate conditions for which the two models allowed to recover the same temperature patterns. Thus, it has been shown that suitable conditions can be found for which the simplified analytical model can lead to an easy way to predict the heat transfer through the pipe. G. Cuccurullo, L. Giordano, and G. Viccione Copyright © 2013 G. Cuccurullo et al. All rights reserved. Tue, 30 Apr 2013 08:59:55 +0000 http://www.hindawi.com/journals/ame/2013/658085/ Dry sliding wear test was conducted on Al-fly ash composites employing pin-on-disc wear testing rig. The influence of parameters such as weight percentage of fly ash, load, and sliding speed on the wear rate of specimens was investigated. Specimens were fabricated by adapting a modified two-step stir casting method. The Taguchi and analysis of variance (ANOVA) techniques were employed to investigate the influence of parameters on the wear rate of composite. Multiple linear regression models were developed to predict the wear rate of the composites. It was found that the weight percentage of fly ash was the most dominant factor influencing the wear rate followed by the applied load and sliding speed. The morphology of worn surfaces of the wear pins was analyzed by scanning electron microscope (SEM) to analyze the wear behaviour. EDS analysis was carried out to investigate the mechanical mixed layer (MML), which forms on the worn surface of the wear pins. Shanmughasundaram Palanisamy, Subramanian Ramanathan, and Ravikumar Rangaraj Copyright © 2013 Shanmughasundaram Palanisamy et al. All rights reserved. Sun, 28 Apr 2013 09:26:48 +0000 http://www.hindawi.com/journals/ame/2013/257283/ The purpose of this paper is to contribute to the understanding of unsteady flow of branch pipes in pneumatic systems. Branch pipes are used in pneumatic pipe systems in various industrial fields. To predict the unsteady pressure changes in the pneumatic piping systems, it is necessary that the dynamic characteristics of branch pipes are at hand, in addition to the dynamic characteristic of single pipe. However, while so many studies are accumulated for a single pipe dynamics, few studies have reported the pressure changes in branch pipes due to oscillatory flow. This paper reports an experimental study on the dynamic characteristics of the pressure change in a pneumatic branch pipe under given oscillatory flow. The paper also proposes a simulation method to predict the pressure changes in a pneumatic branch pipe under oscillatory flow. The validity of simulation is verified for oscillatory flows up to 5 Hz, comparing with the experimental results. Daisuke Sakamoto, Chongho Youn, and Toshiharu Kagawa Copyright © 2013 Daisuke Sakamoto et al. All rights reserved. Mon, 22 Apr 2013 13:49:06 +0000 http://www.hindawi.com/journals/ame/2013/178680/ A Dyna Technologies Inc. GP-5000HT precision glass molding machine has been found to be a capable tool for bridging the gap between research-level instruments and the higher volume production machines typically used in industry, providing a means to apply the results of rigorous instrumentation analysis performed in the lab to industrial PGM applications. The GP-5000HT’s thermal and mechanical functionality is explained and characterized through the measurement baseline functionality and the associated error. These baseline measurements were used to determine the center thickness repeatability of pressed glass parts, which is the main metric used in industrial pressing settings. The baselines and the repeatability tests both confirmed the need for three warm-up pressing cycles before the press reaches a thermal steady state. The baselines used for pressing a 2 mm glass piece to a 1 mm target center thickness yielded an average center thickness of 1.001 mm and a standard deviation of thickness of 0.0055 mm for glass samples pressed over 3 consecutive days. The baseline tests were then used to deconvolve the sources of error of final pressed piece center thickness. Peter Wachtel, Peiman Mosaddegh, Benn Gleason, J. David Musgraves, and Kathleen Richardson Copyright © 2013 Peter Wachtel et al. All rights reserved. Sun, 21 Apr 2013 13:19:01 +0000 http://www.hindawi.com/journals/ame/2013/986984/ In this research, the heat transfer model of surface grinding temperature field with nanoparticle jet flow of MQL as well as the proportionality coefficient model of energy input workpiece was established, respectively. The numerical simulation of surface grinding temperature field of three workpiece materials was conducted. The results present that, in the workpiece, the surface temperature was significantly higher than the subsurface temperature, presenting relatively large temperature gradient along the direction of workpiece thickness. The impact of the grinding depth on grinding temperature was significant. With the increase of the cut depth, peak values of the grinding temperature rocketed. Distribution rules of the temperature field of 2Cr13 in four cooling and lubrication approaches were the same. Based on the excellent heat transfer property of nanofluids, the output heat through the grinding medium acquired an increasingly high proportion, leading to the drop of the temperature in the grinding zone. For the same cooling and lubrication conditions, grinding temperature presented insignificant changes along the direction of grinding width. Yet, under different cooling conditions, the temperature variation was significant. MQL grinding conditions with additive nanoparticles demonstrated great impact on the weakening of temperature effect on the grinding zone. C. H. Li, J. Y. Li, S. Wang, and Q. Zhang Copyright © 2013 C. H. Li et al. All rights reserved. Sun, 21 Apr 2013 10:40:30 +0000 http://www.hindawi.com/journals/ame/2013/258506/ This paper compares and analyzes the quantitative diagnosis methods based on Lempel-Ziv complexity for bearing fault, using continuous wavelet transform (CWT), Empirical Mode Decomposition (EMD) method, and wavelet packet method for decomposition of vibration signal measured by acceleration sensors, respectively. The kurtosis and entropy indices are also analyzed in order to select the optimum analysis area from the vibration signal. The variation trend of vibration signal Lempel-Ziv complexity of bearing inner race and outer race with the varying fault severity is analyzed and predicted based on the generation mechanism and characteristics of fault vibration signals. Experimental results show that it is suitable for observing the fault growing trend and severity by examining the value based on improved Lempel-Ziv complexity algorithm using continuous wavelet transform (CWT), Empirical Mode Decomposition (EMD) method, and wavelet packet method for signal decomposition, using kurtosis indices for optimal analysis area selection, and using the optimal weight coefficients for complexity calculation. Jing Wang, Lingli Cui, Huaqing Wang, and Peng Chen Copyright © 2013 Jing Wang et al. All rights reserved. Thu, 18 Apr 2013 15:45:49 +0000 http://www.hindawi.com/journals/ame/2013/474935/ This paper presents the results of a CFD analysis and experimental tests of two identical miniature flat plate heat pipes (FPHP) using sintered and screen mesh wicks and a comparative analysis and measurement of two solid copper base plates 1 mm and 3 mm thick. It was shown that the design of the miniature FPHP with sintered wick would achieve the specific temperature gradients threshold for heat dissipation rates of up to 80 W. The experimental results also revealed that for localised heat sources of up to 40 W, a solid copper base plate 3 mm thick would have comparable heat transfer performances to that of the sintered wick FPHP. In addition, a marginal effect on the thermal performance of the sintered wick FPHP was recorded when its orientation was held at 0°, 90°, and 180° and for heat dissipation rates ranging from 0 to 100 W. R. Boukhanouf and A. Haddad Copyright © 2013 R. Boukhanouf and A. Haddad. All rights reserved. Thu, 18 Apr 2013 13:07:41 +0000 http://www.hindawi.com/journals/ame/2013/287963/ A modeled room was numerically heated from a wall and cooled from the opposite wall in order to create a real-room simulation. The cooled wall simulated heat loss of the room, and the heated wall simulated the heat source of enclosure. The effects of heated and cooled wall temperatures on convective heat transfer coefficient (CHTC) and Nusselt number in the enclosure were investigated numerically for two- (2D) and three-dimensional (3D) modeling states. Different hot wall and cold wall temperatures were applied in order to obtain correlations that contained characteristic length in Rayleigh numbers. Results were compared with the results of previously reported correlations that have been suggested for vertical room surfaces in enclosures. In addition, new correlations for Nusselt number and average CHTC for enclosures for isothermal boundary conditions within indicated Rayleigh number ranges were derived through solutions. Average deviations of new correlations obtained for CHTC and Nusselt number from the numerical data were found 0.73% and 1.76% for 2D study, 3.01% and 0.49% for 3D study. It was observed that the difference between the 2D and 3D solutions in terms of CHTC and Nusselt number was approximately 10%. Ozgen Acikgoz and Olcay Kincay Copyright © 2013 Ozgen Acikgoz and Olcay Kincay. All rights reserved. Wed, 17 Apr 2013 11:15:56 +0000 http://www.hindawi.com/journals/ame/2013/708785/ In order to study the relation between the food package temperature and ambient environment, the food package temperature is investigated by numerical simulation under the different conditions, such as evaporator outlet velocities, ambient temperatures, and relative humidity. In the present computation, the influence of mass transfer and radiation is considered. The computational results show that the front and top food package temperature rises to due to the effect of light. At the investigated range of this paper, the food package temperature decreases when the air curtain velocity increases, but the food package temperature also increases with increase of ambient temperature and humidity. At the same time, the food package temperature decreases when air curtain outlet velocity increased by 0.15 m/s. The food package temperature rises about 0.6°C when ambient temperature increases by 2°C. The food package temperature rises about 0.9°C when ambient humidity increases by 20%. Therefore, the study can provide the reference for the design of refrigerated display cabinet. Chang Zhijuan, Wu Xuehong, Lu Yanli, Ma Qiuyang, and Zhang Wenhui Copyright © 2013 Chang Zhijuan et al. All rights reserved. Tue, 16 Apr 2013 10:50:22 +0000 http://www.hindawi.com/journals/ame/2013/107193/ The effect of a flat plate bottom reflector on a vertical multiple-effect diffusion solar still coupled with a basin-type still is analyzed theoretically at 30°N latitude. The still has a right-angled triangular cross-section consisting of a horizontal basin liner, a sloping double glass cover, and the vertical multiple-effect diffusion still (multiple-effect section) at the vertical rear wall. A geometrical model was constructed to calculate the amount of solar radiation reflected by the reflector and absorbed on both the basin liner and the first partition of the multiple-effect section. The reflected radiation from the reflector can be a thermal input to the multiple-effect section both in cases where the reflected radiation is absorbed on the basin liner and on the first partition. It is predicted that the overall daily productivity of the still can be increased about 16%, 13%, and 29% on the spring and autumn equinoxes, the winter solstice, and the summer solstice, respectively, by adding the external reflector and setting the reflector inclination to the proper angle according to seasons. Hiroshi Tanaka Copyright © 2013 Hiroshi Tanaka. All rights reserved. Tue, 16 Apr 2013 07:50:12 +0000 http://www.hindawi.com/journals/ame/2013/476537/ Laminar mixed convection in the entrance region of horizontal and inclined semicircular ducts has been investigated. The governing momentum and energy equations were solved numerically using a marching technique with finite control volume approach following the SIMPLER algorithm. Results were obtained for thermal boundary condition of uniform heat input axially and uniform wall temperature circumferentially, incorporating Pr = 7, Re = 500, inclination angles ( and ), and a wide range of Grashof numbers. These results include velocity and temperature distributions at different axial locations as well as axial distribution of local Nusselt number and local wall friction factor. It was found that Nusselt number is close to the forced convection values near the entrance region, then decreases to minimum value as the distance from the entrance increases, and then rises due to the effect of free convection before reaching a constant value (fully developed). As Grashof number increases Nusselt number and wall friction factor increase in both developing and fully developed regions for horizontal and inclined ducts. A comparison with the experimental data in the thermal entrance region was also conducted and the comparison was satisfactory. Yousef M. F. El Hasadi Copyright © 2013 Yousef M. F. El Hasadi. All rights reserved.