http://www.hindawi.comThe latest articles from Hindawi Publishing Corporation© 2012, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/ame/2012/789515/Infrared (IR) heating as alternative to forced air heating has been studied experimentally for 70 days in two identical, small-scale, experimental greenhouses. The two heating options were implemented with four IR electric lamps and an electric forced air heater correspondingly. The microclimate in the greenhouses was monitored with thermocouples. Parameters characterizing the outdoors macroclimate were also monitored. Lettuce was used as the test crop, and the two heating systems were operated automatically to maintain a suitable reference temperature at the canopy. The investigation focused on night heating needs. Results indicated that the internal air temperature in the IR-heated greenhouse was always kept several degrees lower than the value targeted for the canopy. This lower temperature resulted in 43% average energy savings for the IR-heated greenhouse, compared to the conventionally heated one. A simple numerical model was used to estimate the potential energy savings in a production-scale greenhouse.A. Kavga, G. Alexopoulos, V. Bontozoglou, S. Pantelakis, and Th. PanidisCopyright © 2012 A. Kavga et al. All rights reserved.http://www.hindawi.com/journals/ame/2012/316806/The renovation of biomass waste in the form of date seed waste into activated carbon and biofuel by fixed bed pyrolysis reactor has been focused in this study to obtain gaseous, liquid, and solid products. The date seed in particle form is pyrolysed in an externally heated fixed bed reactor with nitrogen as the carrier gas. The reactor is heated from 400°C to 600°C. A maximum liquid yield of 50 wt.% and char of 30 wt.% are obtained at a reactor bed temperature of 500°C with a running time of 120 minutes. The oil is found to possess favorable flash point and reasonable density and viscosity. The higher calorific value is found to be 28.636 MJ/kg which is significantly higher than other biomass derived. Decolonization of 85–97% is recorded for the textile effluent and 75–90% for the tannery effluent, in all cases decreasing with temperature increase. Good adsorption capacity of the prepared activated carbon in case of diluted textile and tannery effluent was found.Mohammad Uzzal Hossain Joardder, Md. Shazib Uddin, and Mohammad Nurul IslamCopyright © 2012 Mohammad Uzzal Hossain Joardder et al. All rights reserved.http://www.hindawi.com/journals/ame/2011/529049/Experimental tests were carried out to investigate the effects of adding water-based ferrofluid to diesel fuel in a diesel engine. These effects included the combustion performance and exhaust emission characteristics of the diesel engine. To this end, emulsified diesel fuels of 0, 0.4, and 0.8 ferrofluid/diesel ratios by volume were used in a four-stroke diesel engine, operating at 2200 rpm. The results indicate that adding ferrofluid to diesel fuel has a perceptible effect on engine performance, increasing the brake thermal efficiency relatively up to 12% and decreasing the brake-specific fuel consumption relatively up to 11% as compared to diesel fuel. Furthermore, from the analysis of gaseous species of engine exhaust, it was found that NOx emissions were lower than that of diesel fuel while the CO emissions increased. In addition, it was found that nanoparticles can be collected at the exhaust flow using a magnetic bar.M. B. Shafii, F. Daneshvar, N. Jahani, and K. MobiniCopyright © 2011 M. B. Shafii et al. All rights reserved.http://www.hindawi.com/journals/ame/2011/485138/The present paper proposes a novel cableless magnetic actuator with a new propulsion module that exhibits a very high thrusting force. This actuator contains an electrical inverter that directly transforms DC from button batteries into AC. The electrical DC-AC inverter incorporates a mass-spring system, a reed switch, and a curved permanent magnet that switches under an electromagnetic force. The actuator is moved by the inertial force of the mass-spring system due to mechanical resonance energy. The experimental results show that the actuator is able to move upward at a speed of 19.7 mm/s when using 10 button batteries when pulling a 20 g load mass. This cableless magnetic actuator has several possible applications, including narrow pipe inspection and maintenance.Hiroyuki Yaguchi and Tomohiro IzumikawaCopyright © 2011 Hiroyuki Yaguchi and Tomohiro Izumikawa. All rights reserved.http://www.hindawi.com/journals/ame/2011/153731/This paper presents the analysis of static bending of beams made of functionally graded piezoelectric materials (FGPMs) under a combined thermo-electro-mechanical load. The Euler Bernoulli theory (EBT), first-order shear deformation theory (FSDT) and third-order shear deformation theory (TSDT) were employed to compare the accuracy and the reliability of each theory in applications. The material properties vary continuously through the thickness direction. The material compositions were selected from the PZT family. The governing equations were derived from Hamilton's principle and solved using the finite element method and Fourier series method. Cubic Hermit interpolation shape function was used for estimating the transverse deflection, and the linear interpolation function was used for the axial displacement and the shear rotation as well. Fourier series expansion, based on the boundary conditions, were employed to solve the governing equations analytically. The accuracy of the method was validated by comparing the results with the previous studies. Finite element results were compared with the analytical results presented in this paper. A comprehensive parametric study is conducted to show the influence of the voltage, shear deformation, material composition, end supports, and the slenderness ratio on the thermo-electro-mechanical characteristic.Amin Komeili, Abdol Hamid Akbarzadeh, Arezou Doroushi, and Mohammad Reza EslamiCopyright © 2011 Amin Komeili et al. All rights reserved.http://www.hindawi.com/journals/ame/2011/790975/Inconel 718 has found its niche in many industries, owing to its unique properties such as high oxidation resistance and corrosion resistance even at very high temperatures. Coated carbide tool with hard layer of PVD TiAlN is used to turn Inconel 718. Taguchi method with the orthogonal array L9 is applied in this experiment with the parameter cutting speed of 60–80 m/min, feed rate of 0.2–0.3 mm/rev, and depth of cut of 0.3–0.5 mm. The results show that depth of cut is a significant influence to the tool life. Cutting speed of 60 m/min, feed rate of 0.2 mm/rev, and depth of cut of 0.3 mm are the optimum parameters. The flank wear, crater wear, notch wear, and nose wear are the wear mechanisms on the carbide tool. Through the SEM, abrasion, attrition, and adhesion are the wear mechanisms which can be seen on the cutting tool.Gusri Akhyar Ibrahim, Che Hassan Che Haron, Jaharah Abdul Ghani, Ahmad Yasir Moh. Said, and Moh. Zaid Abu YazidCopyright © 2011 Gusri Akhyar Ibrahim et al. All rights reserved.http://www.hindawi.com/journals/ame/2011/408524/An ANN model is proposed to predict the impurity concentration in solid diffusion process when the diffusion coefficient is not known using back-propagation learning technique based on insufficient data for analytical solution. The proposed model was very competitive against the analytical method as the results showed high-performance results with minimal amount of error comparing to the analytical method. Moreover, the proposed ANN model can be used where the analytical methods cannot as in some situations where the diffusion coefficient is not availableIyad M. Muslih, Mohammad A. Mansour, and Saleem Z. RamadanCopyright © 2011 Iyad M. Muslih et al. All rights reserved.http://www.hindawi.com/journals/ame/2011/103502/An experimental investigation has been carried out to study the effect of delta-shaped obstacles mounted on the absorber surface of an air heater duct with an aspect ratio 6 : 1 resembling the conditions close to solar air heaters. This study encompassed the Reynolds number (Re) ranging from 3400 to 27600, longitudinal pitch of the obstacle (Pl/e) varied from 3/2 to 11/2, and relative obstacle height (e/H) varied from 0.25 to 0.75. The relative obstacle transverse pitch (Pt/b)=7/3 and the angle of attack of flow on obstacle = 90° are kept constant during the whole experimentation. By comparing the heat transfer data obtained from the obstacle-mounted duct with that of smooth duct under similar geometrical and flow conditions, the obstacle-mounted duct enhances the heat transfer by 3.6-times at Re=7276.82, Pl/e=3/2, and e/H=0.75.Adisu Bekele, Manish Mishra, and Sushanta DuttaCopyright © 2011 Adisu Bekele et al. All rights reserved.http://www.hindawi.com/journals/ame/2011/251546/The Meshless Local Petrov-Galerkin (MLPG) method is applied for solving the three-dimensional steady state heat conduction problems. This method is a truly meshless approach; also neither the nodal connectivity nor the background mesh is required for solving the initial boundary-value problems. The penalty method is adopted to enforce the essential boundary conditions. The moving least squares (MLS) approximation is used for interpolation schemes and the Heviside step function is chosen for representing the test function. The numerical results are compared with the exact solutions of the problem and Finite Difference Method (FDM). This comparison illustrates the accuracy as well as the capability of this method.M. J. Mahmoodabadi, R. Abedzadeh Maafi, A. Bagheri, and G. H. BaradaranCopyright © 2011 M. J. Mahmoodabadi et al. All rights reserved.http://www.hindawi.com/journals/ame/2011/701263/The purpose of this study was to investigate the effect of varying the outer diameter of screws of a vertebral fixation system by submitting them to mechanical tests and photoelasticity. The pullout mechanical test was performed in 20 swine lumbar vertebrae, divided into two groups based on the screw outer diameter: 5.0 and 6.0 mm. The maximal pullout strengths and stiffness were evaluated. For the photoelasticity, eight models were used and divided into the same groups. The maximal pullout strength was 974.12 ± 144.44 N in the 5.0 mm screws and 1537.42 ± 326.95 N in the 6.0 mm screws (P < 0.001). The stiffness was 418.60 ± 62.58 103N/m in the 5.0 mm screws and 502.12 ± 133.45 103N/m in the 6.0 mm screws (P = 0.09). The mean ± SD shear stress of the 5.0 mm screws was 12.90 ± 1.87 KPa and 11.99 ± 2.01 KPa for the 6.0 mm screws. Thus, the 5.0 mm screw had lower pullout and higher shear stress, suggesting that this screw is more susceptible to loosening.Sarah F. Fakhouri, Ariane Zamarioli, Célia R. G. Wichr, Cleudmar A. Araujo, Helton L. A. Defino, and Antônio C. ShimanoCopyright © 2011 Sarah F. Fakhouri et al. All rights reserved.http://www.hindawi.com/journals/ame/2011/782590/Tropical Cyclone (TC) track changes associated with Rossby wave energy dispersion are simulated in a shallow water primitive equation model with an initial field where a TC is located south of a subtropical high. An anticyclone east of the TC appears because of Rossby wave energy dispersion. The connection of the anticyclone with the subtropical high leads to a poleward TC track deflection. The TC eventually moves across the axis of the subtropical ridge. The formation of the track may be attributed to the nonlinear interaction between the subtropical high and the TC. This work validates the conceptual model proposed by previous observational research. The scenario of the nonlinear interaction between the TC and the subtropical high may also be modified through the influence of mesoscale vortices. The main modifications are (1) the anticyclone induced by energy dispersion of the TC weakens, (2) the connection between the anticyclone and the subtropical high is delayed, and (3) the TC shifts more westward and does not move across the ridge axis. We propose that some of the mesoscale vortices are axisymmetrized by the TC and results in an increase in TC size which modifies the properties of the energy dispersion. The phase and group speeds decrease and produce a simulated track deflection to the left compared to the simulation without mesoscale vortices. Our numerical results demonstrate that multiple scale nonlinear interactions have an essential role in influencing TC track changes.Zhexian Luo, Noel E. Davidson, Fan Ping, and Weican ZhouCopyright © 2011 Zhexian Luo et al. All rights reserved.http://www.hindawi.com/journals/ame/2011/737403/This paper investigates the locomotion of a walking robot by delivering a comparative study of three different biologically inspired walking gaits, namely: tripod, ripple, and wave, in terms of ground slippage they experience while walking. The objective of this study is to identify the gait model which experiences the minimum slippage while walking on a ground with a specific coefficient of friction. To accomplish this feat, the robot is steered over a reference path using a waypoint navigation algorithm, and the divergence of the robot from the reference path is investigated in terms of slip errors. Experiments are conducted through closed-loop simulations using an open dynamics engine which emphasizes the fact that due to uneven and unsymmetrical distribution of payload in tripod and ripple gait models, the robot experiences comparatively larger drift in these gaits than when using the wave gait model in which the distribution of payload is even and symmetrical on both sides of the robot body. The paper investigates this phenomenon on the basis of force distribution of supporting legs in each gait model.Umar Asif and Javaid IqbalCopyright © 2011 Umar Asif and Javaid Iqbal. All rights reserved.http://www.hindawi.com/journals/ame/2011/746535/This work evaluates the hole quality on AISI H13 hardened steel using high-speed drilling. Specimens were machined with new and worn out drills with 8.6 mm diameter and (TiAl)N coating. Two levels of cutting speed and three levels of cooling/lubrication systems (flooded, minimum lubrication quantity, and dry) were used. The hole quality is evaluated on surface roughness (Ra) parameter, diameter error, circularity, and cylindricity error. A statistical analysis of the results shows that the cooling/lubrication system significantly affects the hole quality for all measured variables. This analysis indicates that dry machining produces the worst results. Higher cutting speeds not only prove beneficial to diameter error and circularity errors, but also show no significant difference on surface roughness and cylindricity errors. The effects of the interaction between the cooling/lubrication systems, tool wear, and cutting speed indicate that only cylindricity error is influenced. Thus, the conclusion is that the best hole quality is produced with a higher cutting speed using flooded or minimum lubrication quantity independent of drill wear.Lincoln Cardoso Brandão, Frederico Ozanan Neves, and Gregório Christo NocelliCopyright © 2011 Lincoln Cardoso Brandão et al. All rights reserved.http://www.hindawi.com/journals/ame/2011/697316/A method to synthesize a five-bar slider mechanism with variable topology is suggested. Synthesis is carried out in two phases for function generation. In Phase I, synthesis is carried out for three finitely separated positions. In Phase II, it is carried out for two finitely separated positions. A dyadic complex number method is used to write the equations of motion. The method is simple, general and has an increased accuracy over graphical techniques. An application of the five-bar slider mechanism with variable topology is illustrated.Umesh M. Daivagna and Shrinivas S. BalliCopyright © 2011 Umesh M. Daivagna and Shrinivas S. Balli. All rights reserved.http://www.hindawi.com/journals/ame/2011/650871/The present study focus on evolution of compressible vortex ring generated at the open end of a shock tube through accurate measurement of velocity field using Particle Image Velocimetry (PIV). To investigate the unsteady characteristics of embedded shock-free, low Mach number vortex rings, two cases (shock Mach numbers, M=1.27 and M=1.37) are considered for PIV measurements. Time-dependent variations of circulation, core and ring diameters, and ring velocity are calculated from the measured velocity field. Pinching-off process is investigated in detail for both cases. Formation time and the time of complete detachment of the vortex ring from the trailing jet are identified from the velocity and vorticity field. The ring formation is complete at about t*(=tUb/D)=1.75 and 1.65 for M=1.27 and 1.37, respectively, where t is time, Ub is fluid velocity behind the shock at exit, and D is tube diameter. Complete detachment of the vortex ring from the trailing jet is observed at t∗=2 and 2.9 for M=1.27 and 1.37, respectively.C. Lakshmana Dora, D. Saravanan, K. Karunakar, and Debopam DasCopyright © 2011 C. Lakshmana Dora et al. All rights reserved.http://www.hindawi.com/journals/ame/2011/765739/At present day, pipe mill engineers have to deal with challenging technological problems of heavy-wall and high-strength line pipe manufacturing. Numerical analysis of welded large-diameter pipe manufacturing stages is the most efficient way to solve these problems. Corresponding computational technologies and applied software were developed at Physical & Technical Center. Numerical structural analysis of steel plates at various stages of line pipe manufacturing is performed by the finite element method, accounting for geometric and material nonlinearities. The only thing to be done by the engineer in such analysis is to specify required input parameters. All the further process is software controlled. The discrepancy between the numerical analysis results and measured data in the overwhelming majority cases did not exceed 1%.Vladimir V. Aleshin, Viacheslav V. Kobyakov, and Vadim E. SeleznevCopyright © 2011 Vladimir V. Aleshin et al. All rights reserved.http://www.hindawi.com/journals/ame/2010/593689/Effectiveness and efficiency of hydro-cyclone separators are highly dependent on their geometrical parameters and flow characteristics. Performance of the hydro-cyclone can, therefore, be improved by modifying the geometrical parameters or flow characteristics. The mining and chemical industries are faced with problems of separating ore-rich stones from the nonore-rich stones. Due to this problem a certain amount of precious metals is lost to the dumping sites. Plant managers try to solve these problems by stockpiling what could be useless stones, so that they can be reprocessed in the future. Reprocessing is not a sustainable approach, because the reprocessed material would give lower yield as compared to the production costs. Particulate separation in a hydro-cyclone has been investigated in this paper, by using computational fluid dynamics. The paper investigated the influence of various flow and geometric parameters on particulate separation. Optimal parameters for efficient separation have been determined for the density of fluid, diameter of the spigot, and diameter of the vortex finder. The principal contribution of this paper is that key parameters for design optimization of the hydro-cyclone have been investigated.Oboetswe Seraga MotsamaiCopyright © 2010 Oboetswe Seraga Motsamai. All rights reserved.http://www.hindawi.com/journals/ame/2010/528397/In order to overcome numerical instabilities such as checkerboards, meshdependence in topology optimization of continuum structures, a new implementation combined with homogenization method without introducing any additional constraint parameter is presented. To overcome the shortcoming of continuous material distribution by the introduction of finite element approximation, moving least square or modified filter functions are adopted as interpolation function. The method can be viewed as a nature extension of node-based homogenization method and named as material point homogenization method. Continuous size field and continuous density field are constructed, and structural responses' sensitivities are derived. Several representative numerical examples are presented to demonstrate the capability and the efficiency of the proposed approach against some classes of numerical instabilities.Hongwei Zhao, Kai Long, and Z.-D. MaCopyright © 2010 Hongwei Zhao et al. All rights reserved.http://www.hindawi.com/journals/ame/2010/362406/The purpose of this paper is to determine the optimal cutting conditions for surface roughness in a turning process. This process is performed in the final assembly department at a manufacturing company that supplies fluid dynamic bearing (FDB) spindle motors for hard disk drives (HDDs). The workpieces used were the sleeves of FDB motors made of ferritic stainless steel, grade AISI 12L14. The optimized settings of key machining factors, depth of cut, spindle speed, and feed rate on the surface roughness of the sleeve were determined using the response surface methodology (RSM). The results indicate that the surface roughness is minimized when the depth of cut is set to the lowest level, while the spindle speed and feed rate are set to the highest levels. Even though the results from this paper are process specific, the methodology deployed can be readily applied to different turning processes.Karin KandananondCopyright © 2010 Karin Kandananond. All rights reserved.http://www.hindawi.com/journals/ame/2010/621406/Response of fiberglass epoxy composite laminates under low velocity impact loading is investigated using LS-DYNA®, and the results are compared with experimental analysis performed using an instrumented impact test setup (Instron dynatup 8250). The composite laminates are manufactured using H-VARTM© process with basket weave E-Glass fabrics. Epon 862 is used as a resin system and Epicure-W as a hardening agent. Composite laminates, with 10 layers of fiberglass fabrics, are modeled using 3D solid elements in a mosaic fashion to represent basket weave pattern. Mechanical properties are calculated by using classical micromechanical theory and assigned to the elements using ORTHOTROPIC ELASTIC material model. The damage occurred since increasing impact energy is incorporated using ADVANCED COMPOSITE DAMAGE material model in LS-DYNA®. Good agreements are obtained with the failure damage results in LS-DYNA® and experimental results. Main considerations for comparison are given to the impact load carrying capacity and the amount of impact energy absorbed by the laminates.Gautam S. Chandekar, Bhushan S. Thatte, and Ajit D. KelkarCopyright © 2010 Gautam S. Chandekar et al. All rights reserved.http://www.hindawi.com/journals/ame/2010/291630/An ACSR (Aluminum Conductors Steel Reinforced) power line, when it lies in a fire environment, can manifest a permanent elongation and change in bending, as when the conductors attain a temperature of over 500°C, a drastic fall of the mechanical strength of the steel core is caused. This work is a study about the conductor cross-section at the position of the abruption, in case it occurs. This cross section appears to be approximately 62.5% of the original value. Subsequently, two approximative methods of calculating the bending change of overhead lines are shown.C. D. Halevidis, S. D. Anagnostatos, A. D. Polykrati, E. I. Koufakis, and P. D. BourkasCopyright © 2010 C. D. Halevidis et al. All rights reserved.http://www.hindawi.com/journals/ame/2010/342357/Numerical investigation of the combustion of syngas fuel mixture in gas turbine can combustor is presented in this paper. The objective is to understand the impact of the variability in the alternative fuel composition and heating value on combustion performance and emissions. The gas turbine can combustor is designed to burn the fuel efficiently, reduce the emissions, and lower the wall temperature. Syngas mixtures with different fuel compositions are produced through different coal and biomass gasification process technologies. The composition of the fuel burned in can combustor was changed from natural gas (methane) to syngas fuel with hydrogen to carbon monoxide (H2/CO) volume ratio ranging from 0.63 to 2.36. The mathematical models used for syngas fuel combustion consist of the k-ε model for turbulent flow, mixture fractions/PDF model for nonpremixed gas combustion, and P-1 radiation model. The effect of syngas fuel composition and lower heating value on the flame shape, gas temperature, mass of carbon dioxide (CO2) and nitrogen oxides (NOx) per unit of energy generation is presented in this paper. The results obtained in this study show the change in gas turbine can combustor performance with the same power generation when natural gas or methane fuel is replaced by syngas fuels.Chaouki GhenaiCopyright © 2010 Chaouki Ghenai. All rights reserved.http://www.hindawi.com/journals/ame/2010/154287/Dimensional inspection of a manufactured surface by means of a coordinate measuring machine (CMM) produces a set of Cartesian coordinates. The coordinates are processed to yield the geometric tolerance of the surface. This paper presents a new approach to the evaluation of flatness, cylindricity and sphericity tolerance based on surface invariance with regard to the rigid motions. The proposed algorithm transforms, through homogeneous transformation matrices, the coordinates measured to best fit the reference element of the surface class from which the actual measurements were sampled. The transformation matrix is simplified taking into account the invariance of the sum of the squared normal distances of the measured points from the nominal surface as regards some rigid motions. This invariance is a consequence of the invariance as regards some displacements of the nominal surface from which the data points were sampled. In this way, the number of parameters to be optimised is reduced in comparison with the six parameters characterizing the general homogeneous transform matrix. The methodology was computer implemented and numerical simulations were performed for planes, cylinders, and spheres in order to validate the effectiveness of the approach. The results indicate that the proposed algorithm provides accurate and quick assessments.U. Prisco and W. PoliniCopyright © 2010 U. Prisco and W. Polini. All rights reserved.http://www.hindawi.com/journals/ame/2010/121326/The transportation mechanism of single solid particles in pulsating water flow in a vertical pipe was investigated by means of videography and numerical simulations. The trajectories of alumina particles were observed experimentally by stereo videography. The particle diameter was 3 mm or 5 mm, and the pipe diameter was 18 mm or 22 mm. The frequency of flow pulsation was less than or equal to 6.67 Hz. It was found that the critical minimum water flux at which the particle can be transported upward depended on the pulsating pattern. Two types of numerical simulations were conducted, namely, one-dimensional simulations for tracking the vertical motion of the solid particles and two-dimensional simulations of the pulsating pipe flows in an axisymmetric coordinate system. The computer simulations of axisymmetric pipe flows revealed that the time-averaged radial velocity profile of water in the pulsating flows was very different from that in steady pipe flows. The motion of the particles is discussed in detail for a better understanding of the physics of the transport phenomena.Hitoshi Fujimoto, Masahiro Kubo, Takayuki Hama, and Hirohiko TakudaCopyright © 2010 Hitoshi Fujimoto et al. All rights reserved.http://www.hindawi.com/journals/ame/2010/954841/Within the framework of the piecewise homogenous body model, with the use of the three-dimensional geometrically nonlinear exact equations of the theory of elasticity, the method developed for the determination of the stress distribution in the composites with unidirectional locally curved covered fibers is used for investigation of the shear stresses acting along the fibers. All the investigations are carried out for an infinite elastic body containing a single locally curved covered fiber, for the case where there exists the bond covering cylinder with constant thickness between fiber and matrix material are considered. It is assumed that the considered material is loaded at infinity by uniformly distributed normal forces in the fiber lying direction. Under formulation and mathematical solution of the boundary value problem, the boundary form perturbation method is used. The numerical results related to stress distribution in considered body and the influence of geometrical nonlinearity to this distribution are presented and interpreted.Kadriye Simsek Alan and Surkay D. AkbarovCopyright © 2010 Kadriye Simsek Alan and Surkay D. Akbarov. All rights reserved.http://www.hindawi.com/journals/ame/2010/640103/Yarn strength is one of the most significant parameters to be controlled during yarn spinning process. This parameter strongly depends on both the rovings' characteristics and the spinning process. On the basis of their expertise textile technicians are able to provide a raw and qualitative prediction of the yarn strength by knowing a series of fiber parameters like length, strength, and fineness. Nevertheless, they often need to perform many tests before producing a yarn with a desired strength. This paper describes a Feed Forward Back Propagation Artificial Neural Network-based model able to help the technicians in predicting the yarn strength without the need of physically spinning the yarn. The model performs a reliable prediction of the yarn strength on the basis of a series of roving parameters, commonly measured by the technicians before the yarn spinning process starts. The model has been trained with 98 training data and validated with 50 new tests. The mean error in prediction of yarn strength, using the validation set, is less than 4%. The results have been compared with the one obtained by means of a classical method: the multiple regression. Nowadays, the developed model is running in the laboratory of New Mill S.p.A., an important textile company that operates in Prato (Italy).Rocco Furferi and Maurizio GelliCopyright © 2010 Rocco Furferi and Maurizio Gelli. All rights reserved.http://www.hindawi.com/journals/ame/2010/495741/This paper investigated, using experimental method, the suitability of acoustic emission (AE) technique for the condition monitoring of diesel engine valve faults. The clearance fault was adjusted experimentally in an exhaust valve and successfully detected and diagnosed in a Ford FSD 425 four-cylinder, four-stroke, in-line OHV, direct injection diesel engine. The effect of faulty exhaust valve clearance on engine performance was monitored and the difference between the healthy and faulty engine was observed from the recorded AE signals. The measured results from this technique show that using only time domain and frequency domain analysis of acoustic emission signals can give a superior measure of engine condition. This concludes that acoustic emission is a powerful and reliable method of detection and diagnosis of the faults in diesel engines and this is considered to be a unique approach to condition monitoring of valve performance.Fathi Elamin, Yibo Fan, Fengshou Gu, and Andrew BallCopyright © 2010 Fathi Elamin et al. All rights reserved.http://www.hindawi.com/journals/ame/2010/901376/A model to predict the effective thermal conductivity of heterogeneous materials is proposed based on unit cell approach. The model is combined with four fundamental effective thermal conductivity models (Parallel, Series, Maxwell-Eucken-I, and Maxwell-Eucken-II) to evolve a unifying equation for the estimation of effective thermal conductivity of porous and nonporous food materials. The effect of volume fraction (υ) on the structure composition factor (ψ) of the food materials is studied. The models are compared with the experimental data of various foods at the initial freezing temperature. The effective thermal conductivity estimated by the Maxwell-Eucken-I + Present model shows good agreement with the experimental data with a minimum average deviation of ±8.66% and maximum deviation of ±42.76% of Series + Present Model. The combined models have advantages over other empirical and semiempirical models.K. S. Reddy and Karthikeyan PCopyright © 2010 K. S. Reddy and Karthikeyan P. All rights reserved.http://www.hindawi.com/journals/ame/2010/632831/Reduced-order modeling is a systematic way of constructing models with smaller number of states that can capture the “essential dynamics” of the large-scale systems, accurately. In this paper, reduced-order modeling and control techniques for parametrically excited MEMS are presented. The techniques proposed here use the Lyapunov-Floquet (L-F) transformation that makes the linear part of transformed equations time invariant. In this work, three model reduction techniques for MEMS are suggested. First method is simply an application of the well-known Guyan-like reduction method to nonlinear systems. The second technique is based on singular perturbation, where the transformed system dynamics is partitioned as fast and slow dynamics and the system of differential equations is converted into a differential algebraic (DAE) system. In the third technique, the concept of invariant manifold for time-periodic systems is used. The “time periodic invariant manifold” based technique yields “reducibility conditions”. This is an important result because it helps us to understand the various types of resonances present in the system. These resonances indicate a tight coupling between the system states, and in order to retain the dynamic characteristics, one has to preserve all these “resonant” states in the reduced-order model. Thus, if the “reducibility conditions” are satisfied, only then a nonlinear order reduction based on invariant manifold approach is possible. It is found that the invariant manifold approach yields the most accurate results followed by the nonlinear projection and linear technique. These methodologies are general, free from small parameter assumptions, and can be applied to a variety of MEM systems like resonators, sensors and filters. The reduced-order models can be used for parametric study, sensitivity analysis and/or controller design. The controller design is based on the reduced-order system. Thus, first the reduced-order model of the large-scale system is constructed that captures the essential dynamics. If a controller is designed to stabilize this reduced-order system, then it guarantees that the large-scale system is controlled. The theoretical framework to design linear and nonlinear controllers is also presented.Sangram RedkarCopyright © 2010 Sangram Redkar. All rights reserved.http://www.hindawi.com/journals/ame/2010/763718/Detailed flow measurements are essential for analysing flow structures found in confined spaces, particularly in various automotive applications. These measurements will be extremely helpful in solving flow dependent complexities. Although considerable progress has been made in computational techniques for investigating such flows, experimental flow measurements are still very difficult to carry out therein. Flows mapped using an array of robust instruments like multi-hole pressure probes can provide significant insight into the flow field of such complex flows. Pressure probes can withstand the harsh environments found in such applications; however being intrusive devices significant interference in flow field can limit their applicability. This paper presents an investigation of three-dimensional interference caused by multi-hole pressure probes in an automotive wheel arch. It involves simulation of flow around a pressure probe inserted at various locations within the wheel/wheel arch gap. Pressure and velocity fields along longitudinal and lateral planes have been mapped and the extent of interference caused by the probe along three orthogonal axes has been presented. A three-dimensional ellipsoid of interference has been defined to assist in recommending optimal placement of probes and minimise the error due to interprobe interaction, thus enhancing the measurement accuracy of transient flow phenomena.V. Malviya, R. Mishra, and E. PalmerCopyright © 2010 V. Malviya et al. All rights reserved.