bluuebunny/crossref_metadata_2025 huggingface dataset:
A Method of Identifying the Ingredient of Homo-Zeotrope by Measurable Temperature Field of Pipe Convective Heat Transfer Model
Authors: Wang Xin , Mei Ning , Yu Xijun , Li Yan
Published: April 2014

A method of identifying the composition of homo-zeotrope with measuring the pipe convective heat transfer temperature field is shown. In the case of the set pressure and low Reynolds number liquid, consider about the full development period of laminar pipe fluid mechanics characters, heat convection transfer temperature field could be known of numerical method with given model parameters. Calculating equation-controlling nonlinear simulation parameters by inverse problem of the convective heat transfer controlling equation, mix proportion can be worked out by the connection between estimating parameters values and the calculated total parameters of each element. Besides, process error analysis suggests the error of mix proportion in calculated parameters matches the given.
Viscous Dissipation and Soret Effects on Non-Darcy Mixed Convective Flow Considering Nanofluids
Authors: Kameswaran P. K. , Sibanda P. , Murti A. S. N.
Published: April 2014

We investigate the steady boundary layer mixed convective flow over a horizontal impermeable wall embedded in a porous medium filled with a water-based nanofluid. The model used for the nanofluid incorporates the effects of the volume fraction parameter. The main objective of the present study is to investigate viscous dissipation and Soret effects on heat and mass transfer in a nanofluid containing Al2O3 and TiO2 nanoparticles. The temperature and concentrations at the wall were kept constant. A similarity transformation was used to obtain a system of nonlinear ordinary differential equations. The resulting nonlinear governing equations with associated boundary conditions were solved numerically using the Matlab bvp4c solver. The effects of viscous dissipation and the Soret parameter on dimensionless temperature, concentration, heat and mass transfer are presented graphically. It was observed that the heat transfer rate decreased with an increase in nanoparticle volume fraction. Comparison of current and previously published results (Lai and Kulaki [10], Arfin et al. [12]) showed a good agreement.
Modified Multiscale Finite Volume Method for Two Phase Flow in Porous Media
Authors: Saeidimanesh Mahdi , Eksiri Hamed
Published: April 2014

Multiscale finite volume (MSFV) method have been developed and applied in various complicated physics. The most important advantage of MSFV method is its computational efficiency. In this paper we present a new set of boundary condition for calculation of basis and correction functions which leads to further reduction in computational time in problems with medium heterogeneity and therefore improves computational efficiency. In standard MSFV (sMSFV) method reduced boundary condition is used to determine the basis and correction functions which is based on local information, however in modified MSFV (mMSFV) method global information is used at initial time for constructing boundary condition which is needed for computing basis functions. The main idea of the method is to use global initial pressure distribution to determine the boundary condition for the basis and correction functions. There is no need to update these basis and correction functions in porous media with medium heterogeneity at each time step and they are calculated only once at the initial time step. This boundary condition allows us to enter nonlocal effect in to the calculation of basis and correction functions which has great importance especially in highly heterogeneous reservoirs. The two difficulties of sMSFV method are problems with high permeability contrast and problems with course grid aspect ratio. This mMSFV can overcome the limitation of high permeability contrast partly.
Oscillatory Behavior of the Nonlinear Clamped-Free Beam Microgyroscopes Under Electrostatic Actuation and Detection
Authors: Mojahedi Mahdi , Ahmadian Mohammad Taghi , Firoozbakhsh Keikhosrow , Barari Ahmad
Published: April 2014

Vibratory Micromachined gyroscopes use suspending mechanical parts to measure rotation. They have no gyratory component that require bearings, and for this reason they can be easily miniaturized and batch production using micromachining methods. They operate based on the energy interchange between two modes of structural vibration. The objective of this paper is to study the oscillatory behavior of an electrostatically actuated vibrating microcantilever gyroscope with proof mass at its end. In the modelling, the effects of different nonlinearities, fringing field and base rotation are considered. The microgyroscope is subjected to coupled bending oscillations around the static deflection which are coupled by base rotation. The primary oscillation is generated in drive direction of microgyroscope by applying a pair of DC and AC voltages in the tip mass. Secondary oscillation in sense direction is induced by Coriolis coupling when the beam has the input angular rate along longitudinal axis. Input angular rotation can be measured by sensing oscillation tuned by another DC voltage applied to the proof mass. First a system of nonlinear equations which describes flexural-flexural motion of electrostatically actuated microbeam gyroscopes under input rotation, is derived by extended Hamilton principle. The oscillatory behavior of microgyroscopes is then analytically investigated, where the microgyroscopes are predeformed by DC voltages in both directions. The effects of the nondimensional parameters on the natural frequencies of the system are discussed at the end of the paper.
A Feedforward Anti-Windup Scheme for Integral Controllers Inspired on a Deformed Integral Operator
Authors: do Carmo Samaronne N. , Araújo José M.
Published: April 2014

A well-known problem called the windup phenomenon has been comprehensively investigated by control system designers that derate the performance of closed-loop systems using controllers having integral action. In simulation-based tuning, if the windup phenomenon is ignored, even a stable design can yield an unstable system. The main cause of the windup phenomenon is control effort saturation-a very realistic and almost ubiquitously encountered constraint. Several techniques for mitigating the windup phenomenon have been proposed in literature. An exclusive class of techniques called anti-windup techniques has also been described. Such techniques involve the use of internal loops for partial compensation that use the difference between the unsaturated control effort at the controller output and the effective saturated control effort applied at the actuator. Some of these techniques are relatively complex and of higher orders; in some cases, the techniques employ dynamic compensation of the same order as that of the plant. In this paper, we propose a simple feedforward scheme as an anti-windup technique in which the integral operator is deformed; this technique is inspired from the so-called deformed calculus-a generalization of the integrals and derivatives based on the nonextensive statistical mechanics of Tsallis. With regard to deformed integral action, we have prepared a computational method for tuning the q-parameter on the basis of the minimization of an integral square error root square criterion. The proposed scheme has been simulated using examples of feedback systems; the simulation results demonstrate the advantages of the proposed technique in comparison to techniques proposed in related works. Further, a preliminary stability study is formulated in order to investigate the impact of the proposed method on system design.
Numerical Simulation of Natural Ventilation in Large-Scale Industrial Workshops Based on Orthogonal Test Design
Authors: Long Yan , Feng Jinming , Liu Ke , Jin Shiping , Fu Yan
Published: April 2014

In this paper, orthogonal test design method and the CFD method were used to study the different building envelopes, and the outdoor environment of natural ventilation effect of single span of high temperature industrial workshop. Firstly, 18 ventilation models of workshop with heat source were constructed with orthogonal test design. Secondly, 18 ventilation models of workshop with heat source were simulated with CFD method. Finally, the order of the influencing factors on the ventilation of workshop was obtained through multiple index range analysis of the orthogonal experiment results according to the average temperature inside the workshop. Then the optimal combination of the best ventilation effect was selected. The research results can provide effectively theoretical basis for the future industrial plant ventilation design and optimization.
Mechanical Characterization of a Hybrid Carbon Nanotube/Carbon Fiber Reinforced Composite
Authors: Tehrani Mehran , Boroujeni Ayoub Y. , Hajj Ramez , Al-Haik Marwan
Published: April 2014

Carbon fiber reinforced polymer composites (CFRPs) are renowned for their superior in-plane mechanical properties. However, they lack sufficient out-of-plane performance. Integrating carbon nanotubes (CNTs) into structures of CFRPs can enhance their poor out-of-plane properties. The present work investigates the effect of adding CNTs, grown on carbon fibers via a relatively low temperature growth technique, on the on and off-axis tensile properties as well as on transverse high velocity impact (∼100 m.s−1) energy absorption of the corresponding CFRPs. Two sets of composite samples based on carbon fabrics with surface grown CNTs and reference fabrics were fabricated and mechanically characterized via tension and impact tests. The on-axis and off-axis tests confirmed improvements in the strength and stiffness of the hybrid samples over the reference ones. A gas gun equipped with a high-speed camera was utilized to evaluate the impact energy absorption of the composite systems subjected to transverse spherical projectiles. Due to the integration of CNTs, intermediate improvements in the tensile properties of the CFRP were achieved. However, the CFRPs’ impact energy absorption was improved significantly.
Large Amplitude Vibrations of Laminated Rectangular Plates With Free Edges
Authors: Alijani F. , Amabili M.
Published: April 2014

Nonlinear forced vibrations of completely free laminated composite rectangular plates are studied using multi-modal Lagrangian approach. Nonlinear higher-order shear deformation theory is used and the nonlinear response to transverse harmonic excitation in the frequency neighborhood of the fundamental mode is investigated. The numerical analysis is conducted in two steps. First, the plate displacements and rotations are expanded in terms of Chebyshev polynomials and a linear analysis is performed to obtain the natural frequencies and mode shapes. Then, the energy functional is discretized by using the natural modes of vibration and a system of nonlinear ordinary differential equations with cubic and quadratic nonlinear terms is obtained. A pseudo arc-length continuation and collocation scheme is employed to carry out a bifurcation analysis. A consistent reduced-order model necessary to capture the nonlinear dynamics of the plate is developed and the effect of number of modes retained in the numerical model is discussed.
Experimental Investigation of Bicycle Frame FEA Models
Authors: Miles Paul , Archibald Mark
Published: April 2014

This study experimentally investigated pedal cycle frame loads and verified analytical load cases applied to vehicle design. The experimental results were compared with a Finite Element Analysis (FEA) model. The weight of the rider on the seat, road induced loads and vibrations, and the force the rider exerts on the pedals affect the stress state of the frame. Strain gauges were applied to two different frame models. Four different locations were tested on a monotube long-wheel base (LWB) recumbent frame and six locations on a standard upright Schwinn. The stress state was calculated from the raw strain data. Depending on the gauge being used, the results either indicated the von Mises stress or simply the axial stress. The different loading conditions tested were as follows: static, steady pedaling on smooth, mid-grade, and rough pavement, and hard acceleration on level ground and uphill. The static and hard acceleration cases were directly compared to the FEA model. The experimental results were comparable to the FEA analysis. The complexity of the load case, coupled with unknown actual loads, explains the larger differences between FEA and experimental results. Based on experimental results, the FEA model was refined, improving the agreement between model and experiment. The stress states of a bicycle frame were successfully found experimentally, being confirmed by multiple runs under each loading condition. Based on the agreement between the two methods, the use of FEA load cases to predict stresses in pedal cycle frames was verified.
Technologies for Waste Heat Recovery in Off-Shore Applications
Authors: Pierobon Leonardo , Haglind Fredrik , Kandepu Rambabu , Fermi Alessandro , Rossetti Nicola
Published: April 2014

In off-shore oil and gas platforms the selection of the gas turbine to support the electrical and mechanical demand on site is often a compromise between reliability, efficiency, compactness, low weight and fuel flexibility. Therefore, recovering the waste heat in off-shore platforms presents both technological and economic challenges that need to be overcome. However, onshore established technologies such as the steam Rankine cycle, the air bottoming cycle and the organic Rankine cycle can be tailored to recover the exhaust heat off-shore. In the present paper, benefits and challenges of these three different technologies are presented, considering the Draugen platform in the North Sea as a base case. The Turboden 65-HRS unit is considered as representative of the organic Rankine cycle technology. Air bottoming cycles are analyzed and optimal design pressure ratios are selected. We also study a one pressure level steam Rankine cycle employing the once-through heat recovery steam generator without bypass stack. We compare the three technologies considering the combined cycle thermal efficiency, the weight, the net present value, the profitability index and payback time. Both incomes related to CO2 taxes and natural gas savings are considered. The results indicate that the Turboden 65-HRS unit is the optimal technology, resulting in a combined cycle thermal efficiency of 41.5% and a net present value of around 15 M$, corresponding to a payback time of approximately 4.5 years. The total weight of the unit is expected to be around 250 ton. The air bottoming cycle without intercooling is also a possible alternative due to its low weight (76 ton) and low investment cost (8.8 M$). However, cycle performance and profitability index are poorer, 12.1% and 0.75. Furthermore, the results suggest that the once-trough single pressure steam cycle has a combined cycle thermal efficiency of 40.8% and net present value of 13.5 M$. The total weight of the steam Rankine cycle is estimated to be around 170 ton.
Equivalent Linkages and Dead Center Positions of Planar Single-DOF Complex Linkages
Authors: Wang Jun , Ting Kwun-Lon , Zhao Daxing
Published: April 2014

This paper proposes a simple and general approach for the identification of the dead center positions of single-DOF complex planar linkages. This approach is implemented through the first order equivalent four-bar linkages. The first order kinematic properties of a complex planar linkage can be represented by their instant centers. The basic idea behind this method is obvious and straightforward. The condition for the occurrence of a dead center position can be designed as when the three passive joints of the equivalent four-bar linkage become collinear. The proposed method is a general concept in the sense that it can be systematically applied to analyze the dead center positions for any type of single-DOF planar linkages regardless of the number of kinematic loops or the type of the kinematic pairs involved. The velocity method for the dead center analysis is also used to compare the results. The proposed method paves a novel and easy way to analyze the dead center positions for complex planar linkages. This concept is presented for the first time for the dead center analysis of planar complex linkages. Examples of complex linkages are employed to illustrate this concept in this paper.
Investigation of a Vibration Reduction System for Vehicle Seats by a Vibration Model Consisting of a Vehicle, Seat, and Human Body
Authors: Ota S. , Nishiyama S. , Nakamori T.
Published: April 2014

This paper describes a vibration reduction system that can minimize the vertical vibrations of the human body in a vehicle. This system can control the mechanical properties of the seat cushions, such as the spring constants and damping coefficients. To examine the feasibility of this vibration reduction system, we design a vibration model of both an occupant–seat–steering wheel–pedals–vehicle system and a calculation system. Further, we carry out a numerical analysis to calculate the magnitude of vibrations transmitted from the road surface to the human body based on ISO7096-EM6. Comparison results of the frequency response between the analysis and the experiment indicate the feasibilities of both the vibration model and the analysis method. Furthermore, vibration of the head was reduced 60.1% by controlling the mechanical properties of the seat from 1/5 to 5 times. In summary, the in-vehicle vibration reduction system successfully reduces vibrations from the seat to the human body.
Numerical Study of a New Heat Transfer Correlation for Turbulent Air Flow in Noncircular Ducts With Variable Properties
Authors: Yang Mo , Wang Peng , Zhang Yuwen , Wang Zhiyun
Published: April 2014

Turbulent flow of air with variable properties in a set of regular polygonal ducts and circular tube have been numerically simulated. All the ducts have the same hydraulic diameter as their characteristic length dimension in the Reynolds number. The flow is modeled as three-dimensional and fully elliptic by using the finite volume method and the standard k-ε turbulence model is adopted. The performances of the flow and heat transfer have been thoroughly investigated. The results showed that comparatively strong secondary flow can be observed with variable properties fluid. For the regular polygonal duct, the local heat transfer coefficient along circumferential direction is not uniform and there is an appreciable reduction in the corner region. The use of hydraulic diameter for regular polygonal ducts to determine turbulent flow heat transfer from circular tube correlations leads to unacceptably large errors. Based on the simulation results, a correction factor Cϕ is proposed to ameliorate the previous correlations, and the error in the prediction of turbulent heat transfer with the new correlation is within 6%.
Analytical Solutions for Periodic Motions in a Hardening Mathieu-Duffing Oscillator
Authors: Luo Albert C. J. , O’Connor Dennis M.
Published: April 2014

Analytical solutions for period-m motions in a hardening Mathieu-Duffing oscillator are obtained using the finite Fourier series solutions, and the stability and bifurcation analysis of such periodic motions are completed. To verify the approximate analytical solutions of periodic motions, numerical simulations of the hardening Mathieu-Duffing oscillator are presented. Period-1 asymmetric and period-2 symmetric motions are illustrated.
Analysis and Experiment on Dynamic Prediction in Magnesium Hydride Hydrolysis as Hydrogen Generator
Authors: Chao Chung-Hsing , Jen Tien-Chien , Ho Yen-Hsi
Published: April 2014

In this paper, analysis and experimental verification for dynamic modeling of an acid-catalyzed magnesium hydride hydrolysis was used to predict the hydrogen generation yield, rate, and gravimetric hydrogen storage capacity. The result shows that the ratio citric acid to magnesium hydride, the geometric forms of MgH2, and the water handling are crucial to this reaction, while the higher temperatures tend to have faster rates of reactions. Furthermore, the zero-order prediction gives a good result only at a relatively low citric acid to magnesium hydride ratio or low hydrolysis reaction rate. The reaction order is approximately one while the citric acid/magnesium hydride molar ratio remains high or the rate of reaction is high. Finally, considering the geometrical effect on the acid-catalyzed MgH2 hydrolysis, the validated Langmuir equation was used to successfully predict the dynamic hydrogen generation fairly well for most hydrolysis reaction rate.
Uncovering the Mechanism of Soft Tissue Injuries Associated With ACL Tear
Authors: Orsi A. , Vaziri A. , Chakravarthy S. , Canavan P. K. , Goebel R. , Hashemi H. N.
Published: April 2014

Anterior cruciate ligament (ACL) injury is a common and painful injury that occurs approximately 250,000 times annually in the U.S. [1]. Articular cartilage and meniscal injuries are also associated with ACL injuries [2]. ACL injuries can often lead to degenerative osteoarthritis of the articular cartilage [2]. An epidemiology study of athletic injuries by Majewski et al. [3] determined that out of 19,530 sports injuries, 20% were ACL injuries and 8% were medial collateral ligament (MCL) injuries.
Mechatronics Product Design Methodology
Authors: Dorador-Gonzalez Jesus Manuel , Penuelas-Rivas Ulises Martin
Published: April 2014

It is quite common to find information about Product Design methodologies; however these methodologies are focused on Mechanical Design, Electronics Design or even Software Design. A methodology for Mechatronics Design has been developed at the National University of Mexico and has been tested for several years. Now a focus on product design has been included to expand this methodology that was mostly dedicated to one-of-a-kind machine design and not to product design.

This paper presents both the Mechatronics Product Design Methodology and the results obtained in the Product Design course taught to interdisciplinary teams of Mechanical, Mechatronics, Industrial Engineers and Industrial Designers. An assessment of the implementation problems and how these have been solved is presented together with the products developed by the students.
Deflection of Cancellous Bone Screws Under a Cantilever Bending Load
Authors: Vega Carolina , Arshanskiy Maria , Sagar Amrit , Saigal Anil , James Thomas P. , Smith Eric , Cassidy Charles
Published: April 2014

Surgical bone screws can be subjected to cyclic bending loads when plating constructs are used in the fixation of weight bearing members. While extensive research has been conducted on axial loading that leads to screw pull-out, there is a gap in our understanding of how asymmetric bending loads contribute to screw fracture. The focus of this research was to examine the effect of screw length (20 mm and 40 mm) and cancellous bone density (0.48 g/cm3 and 0.24 g/cm3) on the relative stiffness of 6.5 mm cancellous bone screws subjected to a cantilever bending load. It was hypothesized that longer screws in higher density cancellous bone would result in less screw deflection, supporting clinical practice. For testing, synthetic composite bone was used to simulate the characteristics of natural bone while subjecting screws to quasi-static loading with a universal testing machine. Contrary to the hypothesis, neither screw length nor cancellous bone density resulted in a statistically significant difference (p > 0.05) in deflection for loading up 450 N. The cortical shelf appeared to support the majority of the bending load through compression, rather than acting as a fulcrum. When the 3.0 mm cortex was removed, there was a significant difference in deflection due to both screw length and cancellous bone density.
An Analysis on Friction Behavior of Metal Material Under Ultrasonic Vibration
Authors: Yi Dalong
Published: April 2014

Interfacial friction is important for manufacturing processes using ultrasonic vibration since ultrasonic energy is transferred from horn to welding interfaces of work pieces through movement and contact behavior of surfaces. A 3D thermal-mechanical FE model is built to investigate the interfacial friction behavior of ultrasonic vibration by simulating a typical ultrasonic welding (UW) process which uses the technology of ultrasonic vibration to form material joints. The effects of friction coefficient of horn/work piece interface and coefficient of friction work converting to heat on the thermal-mechanical fields of welding interface are investigated.
Structural Dynamic Modifications Using Damped Updated Finite Element Model Updating
Authors: Arora V.
Published: April 2014

An accurate finite element model of a structure is essential for predicting reliably its dynamic characteristics. Such a model can be used to predict the effects of structural modifications for dynamic design of the structure. These structural modifications may be imposed by design alterations for operating reasons. Most of the model updating techniques neglect damping and so these updated models can’t be used for accurate prediction of vibration amplitudes. This paper deals with the basic formulation of finite element model updating method having identified structural damping matrix, and its use for structural dynamic modifications. A case involving actual measured data for the case of F-shaped test structure, which resembles the skeleton of a drilling machine is used to evaluate the effectiveness of FE model updating method incorporating identified structural damping matrix for accurate prediction of the vibration levels and thus its use for structural dynamic modifications. Design modifications in terms of mass and stiffener modifications are introduced to evaluate the effectiveness updated model incorporating damping matrices for structural dynamic modifications. It has been concluded that the FE model updating incorporating identified structural damping matrix can be used for structural dynamic modifications with confidence.
Numerical and Experimental Investigation of Performance and Reliability in New Reverse Osmosis Seawater Desalination High Pressure Pump
Authors: Ye Xiao-yan , Hu Jing-ning , Wang Jing , Feng Yao-ning , Jiang Wei
Published: April 2014

In order to reduce the investment cost and energy consumption of high pressure pump in Seawater Reverse Osmosis desalination project, a new type of multistage high pressure centrifugal pump with two ends of water-lubricated bearings supporting and axial suction was proposed after analyzing the structural feature of the high pressure pump. The numerical simulation method and mesh quality was improved, the pump performance was predicted and optimized. The relationship of the critical speed and logarithmic decay rate with stage was analyzed, and the relationship between the stage and efficiency of multistage pump was combined to analyze the optimal selection for the impeller stages of multistage pump. The experimental results of axial thrust were used to modify theoretical formula of axial thrust and accurately predicated the axial thrust at different operating conditions. A new balancing device with less leakage fluid, high balancing sensitivity and proper restoring force was designed to improve the reliability of axial thrust balancing device. The experimental results show that the efficiency of the new multistage high pressure centrifugal pump is 83.07% which is increased by 3.07 percents when the design flow rate is 220m3/h, and total Head is 620m. The new multistage high pressure centrifugal pump has been applied in the Chinese Zhoushan seawater desalination project, which runs with high efficiency and stability.
Signal Processing Techniques for Ultrasonic Waves to Measure Stresses in Oil Pipelines
Authors: Pereira Paulo , Santos Cleudiane S. , dos Santos Auteliano A.
Published: April 2014

Ensuring the structural integrity of oil pipelines is vital to prevent environmental damage and economic losses. In that sense, it is important to know the magnitude of the stress in the pipe, which must be done using non-destructive techniques. Measuring stress using ultrasonic longitudinal critically refracted waves (LCR) has been applied to pipelines with very promising results. The technique is based on the acoustoelastic theory that relates speed variation of elastic waves traveling in the material with its state of strain. Nevertheless, the signals acquired from piezoelectric transducers in such application may show high levels of noise coming mainly from material sources (grain boundaries, irregularities). The noise makes the measurement of wave velocity difficult, resulting in imprecise evaluations of the stress in the pipeline. The aim of this study is to evaluate techniques for filtering digital signals of LCR waves propagating in an oil pipe fabricated with API 5L X70 steel. We analyzed the signal-to-noise ratio (SNR) of digitalized acquired signals in four circumstances: without treatment; signals treated with successive averages; treated with FIR (Finite Impulse Response) and IIR (Infinite Impulse Response) digital filters, and with the Discrete Wavelet Transform (DWT). The results show that the signals treated with DWT present better SNR compared to the other techniques.
Advanced Automatic Steering Systems for Multiple Articulated Road Vehicles
Authors: Wagner Sebastian , Nitzsche Gunter , Huber Robert
Published: April 2014

This article describes a novel automatic steering system for a 30.73m long double articulated bus equipped with three independent steer-by-wire axles. Two model-based control design approaches are proposed. The first approach uses a kinetic vehicle model to design a train-like guidance system and a force-canceling that avoids excessive mechanical stress in the joints and the chassis.

While the first approach requires high computational efforts, the second approach utilizes a kinematic model to design an extended Ackermann-steering system that performs well on available electronic control units (ECU).

Multi-body-system (MBS) simulations show that both approaches offer high tracking performance and low mechanical stress in the chassis of the vehicle. Furthermore, road tests with the prototype AutoTram® Extra Grand confirm the simulation results.
A New Paradigm Shift for Manufacturing Businesses
Authors: Lu Yuqian , Xu Jenny , Xu Xun
Published: April 2014

Cloud Manufacturing is emerging as a new manufacturing paradigm which is believed to change the way industries and enterprises do their businesses, in that dynamically scalable and virtualized resources are provided as a service over the Internet. It can transform the traditional manufacturing business model, help it align product innovation with business strategy, and create intelligent factory networks that encourage effective collaboration. This paper introduces the concept of Cloud Manufacturing and its characteristics. The relationship between Cloud Manufacturing and other network-based manufacturing paradigms are analysed, together with a discussion on the connection between Cloud Manufacturing and Cloud Computing, intending to highlight the essence of real Cloud Manufacturing. Existing architecture and key functionalities of Cloud Manufacturing systems are introduced to identify an effective way of implementing Cloud Manufacturing. In this paper, a Cloud Manufacturing platform, called SMC (Sustainable Manufacturing Cloud) is proposed to achieve rapid development of customized products. This is envisioned as a prominent future business model and implementation strategy for Cloud Manufacturing, allowing for the easy realization of customized and original requirements. With an industry network consisting of heterogeneous nodes, being either design agencies or fabrication workshops, product innovation and customization can be achieved with minimum investment and effort.
Factors Contributing to Spiral Humerus Fracture During Muscle-Up Exercise
Authors: Matal Megan A. , Barez Fred , Lee John , Wagner David
Published: April 2014

Spiral humerus fractures associated with extreme muscular torsion loading have been well documented in literature. Throwing motions and arm wrestling are the two causes most often researched, while spiral fractures associated with gymnastics have received less attention. The purpose of this study is to explore the factors that may contribute to torsional failure of the humerus while performing a gymnastics move known as a muscle-up. Primary motivation for this study was the result of the author sustaining a spiral fracture to the distal aspect of her left humerus while attempting a muscle-up. To the author’s knowledge, no previous studies analyzing the forces imposed on the upper extremities during a muscle-up have been conducted.

Utilizing the author’s estimated anthropometric measurements and the kinematic and kinetic constraints of the muscle-up activity, the torque acting about the long axis of the humerus was determined in two ways. First, an analytical approach was used to calculate the forces and moments within a simplified linkage representation of the upper extremity for several representative muscle-up postures. The second method was a computer simulation that modeled the entire body with muscles in several different kinematic positions and outputted internal body elbow joint net moments.

The analytical approach resulted in torques between 12.0 N·m and 29.3 N·m. The kinetics derived with the computer simulation revealed joint reaction torques between 13 N·m and 38 N·m and net axial torques between 29.1 N·m and 69.1 N·m acting on the left humerus. The internal moments predicted using the computer simulation were above the author’s minimum predicted torque, 53 N·m, associated with humerus fracture initiation.

Although there may be many factors that contribute to spiral humerus fracture, in this study, it was determined that the kinematic positions of the muscle-up movement are sufficiently extreme so as to produce torques capable of resulting in spiral humerus fracture.
Some Results of Statistical Modeling of the Small-Scale Turbulence Structure Revealed With Consideration of Intermittency
Authors: Nuzhnov Yu. V.
Published: April 2014

Statistical theory of the small-scale structure of turbulent flows with consideration of intermittency is revised and some calculation results of variability constants, including the breakdown coefficients (the scaling exponents) and Kolmogorov constants (for “two-thirds” and the energy dissipation power laws) in the inertial-subrange, are presented.

The theory is constructed on the assumption of the presence of the turbulent and nonturbulent fluid (medium) within the generalized region of a turbulent flow as well as the dissipative and nondissipative fluid within a turbulent fluid. It is assumed that Kolmogorov laws are only true to a dissipative fluid; all small-scale constants of the theory are treated as statistical variability constants and depend on intermittency coefficient. A correlation between inertial-subrange variability constants and intermittency coefficient is established as well as that between the coefficients of the internal and external intermittency. The variability constants were calculated and compared with the data of the well studied (on experimental target) small-scale structure of the nonhomogeneous turbulent flows of a classical type.

In conclusion, one of the distinctive features of the presented theory is that the statistical nature of inertial-subrange variability constants, including scaling exponents in power laws and Kolmogorov constants, was taken into account.
Integrated Study of a Minimum Exergy Destruction Building Conditioning System
Authors: Ferraro Fabrizio , Sciubba Enrico , Toro Claudia
Published: April 2014

The relatively low average conversion efficiency of air-conditioning systems and the recently imposed upper bounds to the final energy use in the heating and cooling of residential buildings suggest to consider new approaches to design less energy intensive systems.

An integrated, exergy-based approach for the optimal matching of internal and external heating plants in building conditioning systems has been proposed — and its theoretical basis discussed — in a previous paper. The procedure allows the designer to obtain a pseudo-optimal integration of the building and its heating plant (heating element + primary energy supply system) and to identify, among a set of alternative solutions for the building under examination, the thermodynamically most efficient plant.

The objective of this paper is to validate the method on a real building in order to demonstrate its practical applicability. The large “Chiostro Hall” (220 square meters, 1245 cubic meters) of the Engineering School of the University “Sapienza” of Roma has been employed as the benchmark. This is the main hall of the building, reconverted from a previously existing Renaissance structure, the old convent of San Lorenzo in Panisperna, which was in turn built on the ruins of a pre-christian roman basilica and of a portion of emperor Nero’s Domus Aurea.

The hall consists of two semi-connected rooms, originally the Refectory of the old Convent, that are now used for public events, conferences and graduation ceremonies.

This structure can be considered as a model case for similar halls in historical buildings, so that the guidelines deriving from the present study can be extended to other similar environments.

The current heating elements are traditional radiators: in our simulations, they have been successively replaced by other elements such as floor and ceiling heating panels and fan coils. Each one of these configurations (the hall and its heating elements) has been modeled and simulated via a commercial CFD code to generate detailed thermal maps and to compute the actual thermal load. Different global “heating chains” were then modeled by coupling solar and hybrid photovoltaic-thermal (PV/T) panels with radiant panels and ground-source heat pumps with fan coils and radiant heating panels. Finally by means of a process simulator software each one of these configurations was analyzed to identify the one that provides the same comfort level with the least exergy use. The procedure also allows to calculate the savings obtained in terms of primary resources.
CFD-Based Reactor Optimization to Minimize the Decomposition in Polymerization Reactions
Authors: Cutright Ervin , Bun Mellitanya , Nixon Justin , Nguyen Dung , Zhang Ning
Published: April 2014

This research is a continuation of the previous research on the simulation of Low Density Polyethylene reactors. The main focus of this research is the stability of the simulation and the optimization of the polymerization to decrease decomposition. Polymerization is a very complex reaction with multiple stages. There are three main stages this research is concentrated about: Polyethylene production, Ethylene decomposition, and Initiator (Acetylene) decomposition. If decomposition occurs, there is a chance of explosion due to the decomposition reaction being exothermic and violent. ANSYS Fluent is a computational fluid dynamics, CFD, software capable of simulating these reactions. The tubular reactor consists of a pipe and an injection port. There are many variables in this reaction that can be manipulated to produce a result such as injection speed and mass fractions of chemical components. The stability of the simulation was insured using a new method, “Jumpstart”, which involves initially injecting an infinitesimally small amount of the decomposition products, in order to successfully trigger decomposition.
Research on Valve and Pump Combined Control of Digital Actuator
Authors: Yongling Fu , Guozhe Zhou
Published: April 2014

This paper describes a new two-stage screw internal feedback digital actuator. It can be driven directly by digital pulse signal output of computer. The internal mechanical position feedback consisting of screw rod and valve spool with thread supplants the traditional position feedback consisting of position sensor and servo valve. The model of digital actuator is established in AMESim simulation environment. The research about valve and pump combined control is carried out based on this model. The part of valve control introduces a compensator to eliminate the error caused by load effect on position servo system. The other part of pump control achieves the purpose of energy-saving through system power matching control. Simulation results show that valve and pump combined control of digital actuator maintains dynamic performance and reduces energy consumption. This method effectively enhances efficiency of the system.
Anthropomorphic and Linear Arm Models for Mechanical Power Tool Testing
Authors: Stücheli Marius , Leutenecker Bastian , Meboldt Mirko
Published: April 2014

Vibrational dynamics of hand-held power tools are relevant for ergonomics and system performance. In application of these tools, the human user is in the force flow, thus has a relevant influence on the vibrations occurring in the human body. For development purpose and valid comparison between tools, reproducible testing is needed. The testing is most useful if it simulates different user types, working poses and muscle activation states, as observed in the tools’ application. The admittance of an anthropomorphic two link arm system strongly depends on the arm pose angles. This work examines how well this angle dependent behaviour can be approximated by a linear mass-spring-damper system, which is easier to build for test rigs. Parameter optimization under the assumption of fixed masses in the linear replacement system showed unsatisfactory fitting of the system dynamics for some arm poses. Therefore the authors recommend to consider building future test rigs in an anthropomorphic arm setup. The work further reveals the importance of implementing adjustable stiffness and damping in test rigs.
Design of Spindle Supported by High Stiffness Water Hydrostatic Thrust Bearing
Authors: Nakao Yohichi , Yamada Kohei , Suzuki Kenji
Published: April 2014

A precision spindle is a key component of the ultra-precision machine tools that are used for machining precision molds for producing various lenses and other precise parts. The machining accuracy required for the parts now reaches several tens of nanometers. In order to achieve the desired machining accuracy, the precise spindle system with high stiffness bearings is inevitably needed for the ultra-precision machine tools. The paper thus deals with a design of a spindle supported by water hydrostatic bearings. An objective of the study is to design the precision spindle supported by the water hydrostatic bearings with the bearing stiffness of 1 kN/μm. Thus the paper presents the design procedure of the hydrostatic thrust bearings. In particular, the design of the bearing restrictors is introduced. The characteristics of water hydrostatic thrust bearings of the designed spindle are investigated theoretically. The influences of the gap sizes and the supply water pressure on the bearing stiffness are given. It is indicated that the bearing stiffness of 1 kN/μm can be obtained by the spindle design. Structure and materials of the developed spindle are also introduced.
On-Line Calculation Method of Exhaust Steam Humidity Based on BP Neural Network for Steam Turbine
Authors: Zheng Likun , Chen Chang , Xie Danmei , Zhang Hengliang , Yu Yanzhi
Published: April 2014

For condensing turbine, steam exhaust point is in wet steam area. The exhaust steam humidity of steam turbine is difficult to get due to lacking of effective measuring method. Calculation of exhaust steam humidity has always been one of the key parts of the analysis of thermal power units. The main factors affecting exhaust steam humidity are turbine load and turbine exhaust pressure etc, and they are of non-linearity. This paper develops a calculation method to calculate exhaust steam humidity based on BP neural network. Taking a N1000-25/600/600 ultra-supercritical (USC) steam turbine as an example, the exhaust steam humidity is calculated and the results show that the method has a good accuracy to meet the needs of the engineering application.
Research on Sealing Structure and Ground Test of Lunar Sample Return Devices
Authors: Zhang Bin , Yu Min , Yang Huayong , Hong Haocen
Published: April 2014

This article is in the background of lunar exploration program, which requires unmanned operation in the environment of ultra high vacuum, extreme temperature, strong radiation and lunar dust. Seal reliability of lunar sample return devices should be guaranteed as well. Principal prototype devices of explosive welding seal and brazing seal are analyzed separately when applied to lunar program, both of their advantages and disadvantages are indicated, and improved schemes are given as well. Besides, a redundant seal combined with o type rubber ring and knife edge indium alloy is put forward, to validate its reliability, a mathematical model based on Roth theory has been developed to describe sealing mechanism and predict the variable leakage, and the ground tests on leak detection for rubber seal and knife edge seal have been set up separately through helium mass spectrometer. According to the test results, nitrile rubber is proved to be better because of its resilience in alternative temperature, lower leakage and permeation. The knife edge indium seal has lower leak rate, and the welding joint quality of indium alloy itself can be guaranteed as well. The redundant seal is considered to have preliminary feasibility while the test environment for leak detection is required to simulate lunar surface still further.
Rayleigh-Taylor Instability Studied With Multi-Relaxation Lattice Boltzmann Method
Authors: Almalowi Saeed J. , Oztekin Dennis E. , Oztekin Alparslan
Published: April 2014

Multi relaxation lattice Boltzmann method is implemented to study Rayleigh-Taylor instabilities. Two immiscible fluids (oil and water) are arrayed into three layers. D2Q9 lattice arrangement for two dimensional computational domains is employed. Density distribution functions for each fluid and distribution functions for the coloring step are determined. The evolution of the interface is identified with the coloring step. Buoyancy and other interaction forces, created by buoyancy, between phases are modeled. Two cases are studied one with periodic boundary condition instead of a side wall, and one bounded on all sides. The study is done with an aspect ratio of two and a density ratio of 1.2. The early and late stages of the instability are characterized. The early stage of both cases shows the initial periodic disturbance being amplified rapidly on the lower interface. The late stages show mushroom-like structures, with significant distortions occurring on the bounded case.
Influence of Fluid Parameters on Vortex Shedding and Other Characteristics of a Herschel-Bulkley Fluid Flow Over a Circular Cylinder
Authors: Bourisli Raed I.
Published: April 2014

Unsteady flow of a Herschel-Bulkley fluid over a stationary, smooth circular cylinder is studied numerically. The effects of fluid parameters such as the Oldroyd number, Od, and the flow index, n, on the flow morphology and various dynamic coefficients are examined. It is found that for shear-thinning fluids (high modified Reynolds numbers) and high Oldroyd numbers (high yield-stress), the flow parameters such as drag and skin-friction coefficients exhibited rather complicated behavior, often with bi- and tri-frequencies. Strouhal number dependence on these parameters was quantified and found to be consistent with recent reported results in the lower Re regime; its qualitative behavior mirrored for the most part what Newtonian fluids did in the range of Re investigated. Physical explanations are given as to why the departure from Newtonian, or simple non-Newtonian fluid, behavior is observed — mainly the combined effect of shear-thinning and the presence of regions of unyielded fluid.