bluuebunny/crossref_metadata_2025 huggingface dataset:
The Genetics of White Matter Lesions
Authors: Assareh Arezoo , Mather Karen A. , Schofield Peter R. , Kwok John B.J. , Sachdev Perminder S.
Published: July 2010

White matter lesions (WMLs), commonly seen as hyperintensities on T2‐weighted MRI scans of healthy elderly individuals, are considered to be related to small vessel disease in the brain, and are often associated with subtle cognitive and functional impairments. WMLs also show a strong correlation with a wide range of neurodegenerative and neuropsychiatric disorders. Although a number of vascular risk factors for WMLs have been identified, genetic factors are also important with twin and family studies reporting high heritability. Mutations in several genes have been described that lead to monogenic disorders manifesting WMLs, such as Fabry disease and CADASIL. Because most individuals with WMLs do not have Mendelian disorders, most of the focus has been on single nucleotide polymorphisms as genetic risk markers for WMLs, either directly or through their interactions with other genes or medical risk factors. Candidate genes examined to date include those involved in cholesterol regulation and atherosclerosis, hypertension, neuronal repair, homocysteine levels, and oxidative stress pathways. In addition, although there have been a few genome‐wide linkage studies, only one genome‐wide association study has been performed. The majority of the genetic findings need independent replication, and studies need to be extended to other candidate genes. Collaborative efforts to examine genome‐wide associations in large samples of both sexes of a broad age range using longitudinal studies are necessary. The identification of individuals genetically at risk of developing white matter lesions will have important implications for recognizing the etiology of WMLs and thereby developing clinical intervention strategies for their prevention.
REVIEW: Oxytocin: Crossing the Bridge between Basic Science and Pharmacotherapy
Authors: Viero Cedric , Shibuya Izumi , Kitamura Naoki , Verkhratsky Alexei , Fujihara Hiroaki , Katoh Akiko , Ueta Yoichi , Zingg Hans H. , Chvatal Alexandr , Sykova Eva , Dayanithi Govindan
Published: July 2010

Is oxytocin the hormone of happiness? Probably not. However, this small nine amino acid peptide is involved in a wide variety of physiological and pathological functions such as sexual activity, penile erection, ejaculation, pregnancy, uterus contraction, milk ejection, maternal behavior, osteoporosis, diabetes, cancer, social bonding, and stress, which makes oxytocin and its receptor potential candidates as targets for drug therapy. In this review, we address the issues of drug design and specificity and focus our discussion on recent findings on oxytocin and its heterotrimeric G protein‐coupled receptor OTR. In this regard, we will highlight the following topics: (i) the role of oxytocin in behavior and affectivity, (ii) the relationship between oxytocin and stress with emphasis on the hypothalamo–pituitary–adrenal axis, (iii) the involvement of oxytocin in pain regulation and nociception, (iv) the specific action mechanisms of oxytocin on intracellular Ca2+ in the hypothalamo neurohypophysial system (HNS) cell bodies, (v) newly generated transgenic rats tagged by a visible fluorescent protein to study the physiology of vasopressin and oxytocin, and (vi) the action of the neurohypophysial hormone outside the central nervous system, including the myometrium, heart and peripheral nervous system. As a short nine amino acid peptide, closely related to its partner peptide vasopressin, oxytocin appears to be ideal for the design of agonists and antagonists of its receptor. In addition, not only the hormone itself and its binding to OTR, but also its synthesis, storage and release can be endogenously and exogenously regulated to counteract pathophysiological states. Understanding the fundamental physiopharmacology of the effects of oxytocin is an important and necessary approach for developing a potential pharmacotherapy.
Biofuels agriculture: landscape‐scale trade‐offs between fuel, economics, carbon, energy, food, and fiber
Authors: BRYAN BRETT A. , KING DARRAN , WANG ENLI
Published: July 2010

First‐generation biofuels are an existing, scalable form of renewable energy of the type urgently required to mitigate climate change. In this study, we assessed the potential benefits, costs, and trade‐offs associated with biofuels agriculture to inform bioenergy policy. We assessed different climate change and carbon subsidy scenarios in an 11.9 million ha (5.48 million ha arable) region in southern Australia. We modeled the spatial distribution of agricultural production, full life‐cycle net greenhouse gas (GHG) emissions and net energy, and economic profitability for both food agriculture (wheat, legumes, sheep rotation) and biofuels agriculture (wheat, canola rotation for ethanol/biodiesel production). The costs, benefits, and trade‐offs associated with biofuels agriculture varied geographically, with climate change, and with the level of carbon subsidy. Below we describe the results in general and provide (in parentheses) illustrative results under historical mean climate and a carbon subsidy of A$20 t−1 CO2−e. Biofuels agriculture was more profitable over an extensive area (2.85 million ha) of the most productive arable land and produced large quantities of biofuels (1.7 GL yr−1). Biofuels agriculture substantially increased economic profit (145.8 million $A yr−1 or 30%), but had only a modest net GHG abatement (−2.57 million t CO2−e yr−1), and a negligible effect on net energy production (−0.11 PJ yr−1). However, food production was considerably reduced in terms of grain (−3.04 million t yr−1) and sheep meat (−1.89 million head yr−1). Wool fiber production was also substantially reduced (−23.19 kt yr−1). While biofuels agriculture can produce short‐term benefits, it also has costs, and the vulnerability of biofuels to climatic warming and drying renders it a myopic strategy. Nonetheless, in some areas the profitability of biofuels agriculture is robust to variation in climate and level of carbon subsidy and these areas may form part of a long‐term diversified mix of land‐use solutions to climate change if trade‐offs can be managed.
The Proximal Radio-ulnar Joint (PRUJ)-plasty for the Lost Elbow: The PRUJ Utilized to Replace the Ulno-humeral Joint
Authors: Younge Derek A. , Ilyas Imran , Singh Herjeet P. , Pant Rajeev , Paramasivan Odathurai
Published: July 2010

Background

The proximal radio-ulnar joint (PRUJ)-plasty is a new biologic procedure devised to restore an elbow joint after the humero-ulnar joint is destroyed by trauma or infection, or after the distal humerus is resected for tumour.

Methods

After osteotomies on either side of the PRUJ, the joint is rotated 90° and fixed to the distal humerus and the proximal ulna, and functions as a vascularized, innervated synovial elbow joint.

Results

Four young patients had the procedure: one after tumour resection of the distal humerus, another for non-union of the distal humerus and an ankylosed elbow, and two for an old arthrodesis of the elbow after an infection years before.

Conclusion

Postoperatively, three patients had an active elbow joint range of movement from 70° to 120°, and one failed and ankylosed again.
Distal Biceps Tendon Repair: Results of a Modified Technique
Authors: Chadwick Carolyn M. , John Joby , Shahane Shantanu A.
Published: July 2010

Background

Surgery is the gold standard of treatment in selected cases of distal biceps tendon rupture. In 2000 Bain et al. described surgical repair using the endobutton through a single anterior incision and showed excellent results allowing patients early active motion.

Methods

Fourteen patients who presented to our hospital with distal biceps tendon rupture were treated using the technique described by Bain et al., utilising a cannulated system to further minimize risk. We present the results following surgery and discuss the supporting literature.

Results

The mean follow up was 24.7 months. The mean flexion strength achieved on the operated side was 102% of the uninjured side and supination strength achieved was 112%. All patients achieved full flexion. Three patients had lack of terminal extension. The mean loss of pronation was 3° and supination 3°. The mean Disabilities of Arm Shoulder and Hand (DASH) score was 6.64. One patient had a good, and 13 patients an excellent outcome according to the Mayo Elbow Performance Index.

Conclusion

We believe this technique is safe and reproducible, allows early active mobilization and, in this series, produced high patient satisfaction and return to near normal function and strength.
Atraumatic Osteonecrosis of the Humeral Head Associated with Pregnancy
Authors: Kumar Vinod , White Alan D. , Venkateswaran Balachandran
Published: July 2010

Osteonecrosis is usually associated with trauma, the use of corticosteroids or alchohol abuse. Osteonecrosis associated with pregnancy has been reported previously and usually involves the femoral head. A case of atraumatic osteonecrosis of the humeral head precipitated by pregnancy is described. This is the second reported case of osteonecrosis of the humerus associated with pregnancy. Osteonecrosis and its association with pregnancy is reviewed.
Bilateral thoracotomy for removal of uncommon postmediastinal multi‐schwannomas
Authors: Lv Xia‐Yi , Luo Wen Zong , Wang Yong‐Qing , Chen Xin , Tu Zheng‐Liang
Published: July 2010

Postmediastinal schwannoma is a kind of neurogenic tumor originating from the neuron sheath in the posterior mediastinum. In the majority of cases these tumors are located in the paravertebral sulcus and the incidence is similar in both sides of the thorax as single or multiple; however, multi‐schwannomas involved in the bilateral postmediastinum are rare. We report a case of postmediastinal multi‐schwannomas and discuss the clinical and surgical treatment. We are aware of no previously published reports on this rare condition.
Supply Chain Coordination in a Market with Customer Service Competition
Authors: Boyaci Tamer , Gallego Guillermo
Published: July 2010

We consider a market with two competing supply chains, each consisting of one wholesaler and one retailer. We assume that the business environment forces supply chains to charge similar prices and to compete strictly on the basis of customer service. We model customer service competition using game‐theoretical concepts. We consider three competition scenarios between the supply chains. In the uncoordinated scenario, individual members of both supply chains maximize their own profits by individually selecting their service and inventory policies. In the coordinated scenario, wholesalers and retailers of each supply chain coordinate their service and inventory policy decisions to maximize supply chain profits. In the hybrid scenario, competition is between one coordinated and one uncoordinated supply chain. We discuss the derivation of the equilibrium service strategies, resulting inventory policies, and profits for each scenario, and compare the equilibria in a numerical study. We find that coordination is a dominant strategy for both supply chains, but as in the prisoner's dilemma, both supply chains are often worse off under the coordinated scenario relative to the uncoordinated scenario. The consumers are the only guaranteed beneficiaries of coordination.
A capture–recapture model for exploring multi‐species synchrony in survival
Authors: Lahoz‐Monfort José J. , Morgan Byron J. T. , Harris Michael P. , Wanless Sarah , Freeman Stephen N.
Published: July 2010

1. Although recent decades have seen much development of statistical methods to estimate demographical parameters such as reproduction, and survival and migration probabilities, the focus is usually the estimation of parameters for individual species. This is despite the fact that several species may live in close proximity, sometimes competing for the same resources. There is therefore a great need for new methods that enable a better integration of demographical data, e.g. the study of synchrony between sympatric species, which are subject to common environmental stochasticity and potentially similar biotic interactions.

2. We propose a mark–recapture statistical model that uses random effect terms for studying synchrony in a demographical parameter at a multi‐species level, adapting a framework initially developed to study multi‐site synchrony to this novel situation. The model allows us to divide between‐year variance in a demographical parameter into a ‘synchronous’ component, common to all species considered, and species‐specific ‘asynchronous’ components, as well as to estimate the proportion of each component accounted for by environmental covariates.

3. We demonstrate the method with data from three colonially breeding auk species that share resources during the breeding season at the Isle of May, Scotland. Mark‐resight information has been collected since 1984 for Atlantic puffins Fratercula arctica, common guillemots Uria aalge and razorbills Alca torda marked as breeding adults. We explore the relationship between synchrony in the species’ survival and two environmental covariates.

4. Most of the between‐year variation was synchronous to the three species, and the same environmental covariates acted simultaneously as synchronising and desynchronising agents of adult survival, possibly through different indirect causation paths.

5. Synthesis and applications. The model proposed allows the investigation of multi‐species synchrony and asynchrony in adult survival, as well as the role of environmental covariates in generating them. It provides insight into whether sympatric species respond similarly or differently to changes in their environment, and helps to disentangle the sources of these differences. The estimated indices of synchrony/asynchrony can facilitate the generation of further hypotheses about similarities/differences in these species’ ecology, such as the potential overlap of wintering areas. The method is readily applicable to other species, ecosystems and demographical parameters.
Affine Deligne–Lusztig varieties in affine flag varieties
Authors: Görtz Ulrich , Haines Thomas J. , Kottwitz Robert E. , Reuman Daniel C.
Published: July 2010

This paper studies affine Deligne–Lusztig varieties in the affine flag manifold of a split group. Among other things, it proves emptiness for certain of these varieties, relates some of them to those for Levi subgroups, and extends previous conjectures concerning their dimensions. We generalize the superset method, an algorithmic approach to the questions of non-emptiness and dimension. Our non-emptiness results apply equally well to thep-adic context and therefore relate to moduli ofp-divisible groups and Shimura varieties with Iwahori level structure.
Consistency Constraint Allocation in Augmented Lagrangian Coordination
Authors: Allison James T. , Papalambros Panos Y.
Published: July 2010

Many engineering systems are too complex to design as a single entity. Decomposition-based design optimization methods partition a system design problem into subproblems, and coordinate subproblem solutions toward an optimal system design. Recent work has addressed formal methods for determining an ideal system partition and coordination strategy, but coordination decisions have been limited to subproblem sequencing. An additional element in a coordination strategy is the linking structure of the partitioned problem, i.e., the allocation of constraints that guarantee that the linking variables among subproblems are consistent. There may exist many alternative linking structures for a decomposition-based strategy that can be selected for a given partition, and this selection should be part of an optimal simultaneous partitioning and coordination scheme. This article develops a linking structure theory for a particular class of decomposition-based optimization algorithms, augmented Lagrangian coordination (ALC). A new formulation and coordination technique for parallel ALC implementations is introduced along with a specific linking structure theory, yielding a partitioning and coordination selection method for ALC that includes consistency constraint allocation. This method is demonstrated using an electric water pump design problem.
Direct Linearization Method Kinematic Variation Analysis
Authors: Leishman Robert C. , Chase Kenneth W.
Published: July 2010

Velocity and acceleration analysis is an important tool for predicting the motion of mechanisms. The results, however, may be inaccurate when applied to manufactured products due to the process variations that occur in production. Small changes in mechanism dimensions can accumulate and propagate, causing a significant variation in the performance of the mechanism. A new application of statistical analysis is presented for predicting the effects of variation on mechanism kinematic performance. The new method is an extension of the direct linearization method developed for static assemblies. This method provides a solution that is a closed form. It may be applied to two-dimensional mechanisms to predict variation in velocity and acceleration due to dimensional variations. It is also shown how form, orientation, and position variations may be included in the analysis to analyze variations that occur within the joints. Only two assemblies are analyzed to characterize the distribution: The first determines the mean, and the second estimates the variance. The system is computationally efficient and well suited for design iteration.
On the Performance of the PSP Method for Mixed-Variable Multi-Objective Design Optimization
Authors: Khokhar Zeeshan Omer , Vahabzadeh Hengameh , Ziai Amirreza , Wang G. Gary , Menon Carlo
Published: July 2010

Practical design optimization problems require use of computationally expensive “black-box” functions. The Pareto set pursuing (PSP) method, for solving multi-objective optimization problems with expensive black-box functions, was originally developed for continuous variables. In this paper, modifications are made to allow solution of problems with mixed continuous-discrete variables. A performance comparison strategy for nongradient-based multi-objective algorithms is discussed based on algorithm efficiency, robustness, and closeness to the true Pareto front with a limited number of function evaluations. Results using several methods, along with the modified PSP, are given for a suite of benchmark problems and two engineering design ones. The modified PSP is found to be competitive when the total number of function evaluations is limited, but faces an increased computational challenge when the number of design variables increases.
Artifact Design and Measurement Error Analysis in the Evaluation of Lead Measurement Accuracy of Helical Gear Using Wedge Artifact
Authors: Komori Masaharu , Takeoka Fumi , Kubo Aizoh , Okamoto Kazuhiko , Osawa Sonko , Sato Osamu , Takatsuji Toshiyuki , Kondo Yohan
Published: July 2010

The reduction in the vibration and noise of gears is an important issue in mechanical devices such as vehicles and wind turbines. The characteristics of the vibration and noise of gears are markedly affected by deviations of the tooth flank form of micrometer order; therefore, strict quality control of the tooth flank form is required. The accuracy of the lead measurement for a gear-measuring instrument is usually evaluated using a helicoid artifact. However, it is difficult to manufacture it with high accuracy because the helix is a complicated geometrical form. To solve this problem, a method of evaluating a gear-measuring instrument using a wedge artifact, which includes a highly precise plane surface, has been proposed. In this research, to put the wedge artifact into practice, a design method of the wedge artifact is developed. In addition, the effects of the measuring condition and the setting error of the wedge artifact on the measurement result are investigated. The uncertainty for the evaluation method using a wedge artifact is assessed by a measurement experiment and simulation.
Optimization and Performance Evaluation of an Integrated Production-Distribution Plan in Supply Chains
Authors: Fahimnia Behnam , Luong Lee , Marian Romeo
Published: July 2010

Supply Chain Management is the process of integrating and utilizing suppliers, manufacturers, distribution centers, and retailers; so that products are produced and delivered to the end-users at the right quantities and at the right time, while minimizing costs and satisfying customer requirements. From this definition, a supply chain includes three sub-systems: procurement, production, and distribution. The overall performance of a supply-chain is influenced significantly by the decisions taken in its production-distribution plan. A production-distribution plan excludes the procurement activities and integrates the decisions in production, transport and warehousing as well as inventory management. Hence, one key issue in the performance evaluation of a supply network is the modeling and optimization of production-distribution plan considering its actual complexity. This paper develops a mixed integer formulation for a two-echelon supply network that expands the previously reported production-distribution models through the integration of Aggregate Production Plan and Distribution Plan as well as considering the real-world variables and constraints. A Genetic Algorithm is designed for the optimization of the developed model. The methodology will be then implemented to solve a real-life problem incorporating multiple time periods, multiple products, multiple manufacturing plants, multiple warehouses and multiple end-users. To demonstrate the capability of the approach, the validation and performance evaluation of this model will be finally studied for the presented case study.
Simulation and Modeling as Effective Product Design Tools
Authors: Nasser Mohamed , Jawad Badih
Published: July 2010

The new military programs push for better products, faster development time and low development costs. It became almost impossible for major hardware changes to be initiated after prototypes were built and tested. Defense industry is forced to use analytical tools to stay competitive in a tough market. The use of simulation and modeling tools in evaluating vehicle performance is becoming an integral part of the design development process in the defense industry. Moreover, building prototypes of complex systems is expensive and it is difficult and time consuming to develop them. Consequently, it is extremely beneficial to know as much as possible about the mechanism and to optimize its dynamic characteristics before the first physical prototype is built. without the need for physical prototypes, it takes the use of simulation and modeling tools to analyze product performance, conduct trade-off studies, and understand design alternatives. Based on simulation and modeling tools, whose target is to facilitate design innovation for the suspension systems without the need for physical prototypes. It takes the use of a Vehicle Dynamics simulation model (VEHDYN), used in conjunction with statistical tools to analyze the vehicle performance, while traversing a various type of terrains at a defined speed for the parameters of interest.
Treadbot Multi-Head Robot for High Throughput Applications
Authors: Derby Stephen J. , McFadden John
Published: July 2010

A new type of robot has been created. It was designed for high speed pick and place operations that range from creating and packaging food items to item picking at a warehouse or precision electronic assembly. The overall concept of this new design was to both remove the return stroke found in most existing robots as well as to never require the overall robot system to come to rest. Neither the distance of the transfer motion nor the overall workspace size determines the cycle time with this new design. Extending the transfer motion range is simply a matter of configuring additional modular units. This design can be scaled to various sizes and speeds depending on the application.
Advanced Design and Manufacture of Face-Hobbed Spiral Bevel Gears
Authors: Simon V.
Published: July 2010

The design and advanced manufacture of face-hobbed spiral bevel gears on computer numerical control (CNC) hypoid generating machines is presented. The concept of face-hobbed bevel gear generation by an imaginary generating crown gear is established. In order to reduce the sensitivity of the gear pair to errors in tooth-surfaces and to the mutual position of the mating members, modifications are introduced into the teeth of both members. The lengthwise crowning of teeth is achieved by applying a slightly bigger lengthwise tooth flank curvature of the crown gear generating the concave side of pinion/gear tooth-surfaces, and/or by using tilt angle of the head-cutter in the manufacture of pinion/gear teeth. The tooth profile modification is introduced by the circular profile of the cutting edge of head-cutter blades. An algorithm is developed for the execution of motions on the CNC hypoid generating machine using the relations on the cradle-type machine. The algorithm is based on the condition that since the tool is a rotary surface and the pinion/gear blank is also related to a rotary surface, it is necessary to ensure the same relative position of the head cutter and the pinion on both machines.
Research on Distributing of Cutting Temperature Field in Plunge Milling Ti Alloy
Authors: Qin Xuda , Ji Xiaolai , Liu Weicheng , Hua Song
Published: July 2010

Theory model of cutting area temperature field is established based on superposition method of thermal source. Finite element simulation analysis of the cutting area temperature field of the workpiece is gotten by the method of the given heat source. Semi-artificial thermocouple method and infrared thermograph are used to measure cutting field temperature of work piece. The comparison among analysis of simulation result, measured value and theory model calculation value shows that they has good compatibility.
Numerical Modeling and Experimental Validation of Bolted Lap Joints With 1D Hysteresis Finite Elements
Authors: Abad J. , Franco J. M. , Lezaun L. , Martinez F. J.
Published: July 2010

The work presented in this paper is part of a larger project for the modeling of dynamic behavior in bolted joints, and it is a further work on the adjustment of bolted joint 3D numerical model. This work shows the study and conclusions of the numerical modeling of a bolted lap joint by means of 1D hysteresis finite element and its validation with dynamical tests. The modeled joint is made up of two plates with a bolt, nut and washer. The behavior curve of the hysteresis element used was obtained by means of a 3D model of the joint, whose parameters and validation were carried out from the results of quasi-static laboratory tests. This procedure could be advantageously extended to any other lap joint given that its computational requirements are less than those required for a detailed 3D modeling.
In-Line Monitoring of Interrupted Cutting Operations
Authors: Bosetti Paolo , Bruschi Stefania , Tondini Francesco
Published: July 2010

Intelligent cutting operations capable to adjust in-line their process parameters in order to accommodate unexpected changes of working conditions are more and more desirable in order to increase the current automation level. In order to do that, a general model of the cutting process under investigation needs to be set up in advance, and then, during cutting, continuously compared with the output of process sensor signals. Among the different phenomena that contribute to the general cutting model, the evaluation of the tool wear is a matter of primary importance. The in-line prediction of tool wear critical levels would indeed prevent the production of components of unacceptable quality. The paper presents the development of a tool condition monitoring system and its preliminary results applied to interrupted cutting operations. In the paper first part, the process sensors implemented in the system for in-line acquisitions are described and their distinctive but complementary function in the system evidenced. Later on, the FE-based numerical model of the reference process is presented together with the approach followed for its calibration. It is shown that the numerical model is well suited to reproduce process mechanics, giving chance to understand how wear advancement affects process parameters and component quality. This knowledge can be exploited in building up a general model for wear evolution. Finally, data acquired by process sensors are further elaborated into process control charts that can help in monitoring the tool state as its wear evolves during cutting.
An On-Machine Separation Method for Straightness, Yawing and Rolling Errors of a Linear Slide
Authors: Fung Eric H. K. , Wong W. O. , Zhu M.
Published: July 2010

A novel method based on Fourier series for the measurement of motion, yawing and rolling error is proposed in this study. In this method, a stationary stage with eight sensors, three of which are laid in the upper row and the rest are positioned in the lower row, is used as the data acquisition device. While the carriage of a lathe is sliding on the bed in one direction, the sensors capture the displacement data from the facing machine profile. Based on the existing “F5S” method, a new method is proposed to obtain the three major time-varying error components, which are the on-machine motion error, the yawing error and the rolling error, together with the shape functions of the machine profile. Mathematical proof and working principle are included in the paper. Verification of the method applicability is carried out by computer simulation. To evaluate the results of the method, the input data and calculated data are compared. It is shown that the new method is capable to separate all input error components with acceptable accuracy.
Effects of Vortices on Sound Propagation
Authors: Jones R. Michael , Bedard Alfred J.
Published: July 2010

Our simulations indicate that the presence of a vortex in or near acoustic propagation paths can have profound effects on the distributions of sound energy and cause sound waves to originate from virtual source positions. For example, recent studies have shown that infrasonic energy arrives from the regions of hurricanes. The azimuths measured for a limited number of cases published to date do not seem to originate from the vortex cores; but rather from the periphery of the system. This raises the questions: Is the sound being affected by strong wind and temperature gradients with the measured azimuths indicating virtual source positions? -or- Is the sound generation mechanism located outside of the vortex core?
Effects of Pre-Injection on Combustion Characteristics of a Single-Cylinder Diesel Engine
Authors: Mittal M. , Zhu G. , Stuecken T. , Schock H. J.
Published: July 2010

Multiple injections used for diesel engines, especially pre- and post-injections, have the potential to reduce combustion noise and emissions with improved engine performance. This paper outlines the combustion characteristics of a single-cylinder diesel engine with multiple injections. The effects of pre-injection (multi-injection) on combustion characteristics are presented in a single-cylinder diesel engine at different engine speeds and load conditions. A common rail fuel system with a solenoid injector, driven by a peak and hold circuit, is used in this work. This enables us to control the number of injections, fuel injection timing and duration, and the fuel rail pressure that can be used to optimize the engine combustion process (e.g., eliminate engine knock). Mass fraction burned and burn durations are determined by analyzing the measured in-cylinder pressure data. Results are compared with the cases when no pre-injection was used, i.e. only main injection, at the same engine speeds and load conditions. In each study, different cases are considered with the variation in main injection timing. It is found that at full-load condition and lower engine speeds pre-injection is an effective method to alter the engine burn rate and hence to eliminate knock.
Fractal Compression and Adaptive Sampling With HV Partitioning: Accelerating the Scanning Process in Scanning Probe Microscopy
Authors: Cheng Marvin H.-M. , Bakhoum Ezzat G.
Published: July 2010

Typically, a scanning probe microscope (SPM) moves the scanning tip along a zig-zag trajectory. For a given scanning mechanism, the time needed to image an area depends mainly on the number of samples and the size of the image. The imaging speed is further compromised by drifts associated with the substrate and the piezo scanner. It is therefore desirable to improve the imaging speed with limited impact to the effective resolution of the resulting image. In this paper, an adaptive sampling algorithm based on the fractal compression theory of iterated transformations is proposed to address the tradeoff between scanning time and resolution. Instead of scanning a substrate pixel by pixel in an ordered way, the proposed adaptive algorithm starts with a coarse mode scan, measuring only the registered positions within blocks of determined size. Registered positions are defined to constitute the four corners of a specified block. A unique feature of the proposed algorithm is that if the differences among the four registered positions are greater than a preset threshold, the scan process will automatically switch from a coarse mode scan to a zoom-in mode scan. The original block is then divided into two subblocks with HV partitioning method. In the zoom-in mode scan, the microscope uses a finer resolution to scan one of two subblocks. Each sub-block is then treated as another specified block, and the process of coarse mode scanning is repeated until the desired image is synthesized. The main characteristic of this approach is based on the assumption that image redundancy can be efficiently exploited on a block-wise basis. This procedure is particularly relevant to SPMs designed around closed-loop feedback scanners which are gaining in popularity because of their ability to eliminate drift and hysterisis. By applying an adaptive sampling scheme, we have demonstrated that the number of the required samples can be significantly reduced and the scanning process can be accelerated with minimal impact to the image quality.
Thermal Elastohydrodynamic Lubrication Analysis for Point Contact Transmission
Authors: Huang Hai-zhou , Niu Xi-chuan , Yuan Xiao-yang
Published: July 2010

To investigate the thermal EHL (elastohydrodynamic lubrication) in point contact transmission, a model considering the two-dimensional surface velocity of tooth face and the running-in is proposed. The numerical solutions for pressure, temperature and film thickness distribution in the contact zone are obtained by solving equations including the Reynolds, Energy and the elastic displacement with variable dimension meshing method. The model was used to study the point contact transmission of the circular arc gear in a windlass. The main results show that it is pure rolling along the direction of tooth width, and the rolling speed plays a leading role in improving the lubricating performance and transmission efficiency of circular arc gear. The squeeze film effect makes the pressure peak tend to be gentle and the film thickness increase slightly.
Numerical Study on Electrokinetic Interaction Between a Pair of Cylindrical Colloidal Particles
Authors: Fernandes Dolfred Vijay , Kang Sangmo , Suh Yong Kweon
Published: July 2010

Electrophoresis is the motion of dispersed particles relative to a fluid under the influence of an electric field. Presently this phenomenon of electrokinetics is widely used in biotechnology for the separation of proteins, sequencing of polypeptide chains etc. The separation efficiency of these biomolecules is affected by their aggregation. Thus it is important to study the interaction forces between the molecules. In this study we calculate the electrophoretic motion of a pair of colloidal particles under axial electric field. The hydrodynamic and electric double layer (EDL) interaction forces are calculated numerically. The EDL interaction force is calculated from electric field distribution around the particle using Maxwell stress tensor and the hydrodynamic force is calculated from the flow field obtained from the solution of Stokes equations. The continuous forcing approach of immersed boundary method is used to obtain flow field around the moving particles. The EDL distribution around the particles is obtained by solving Poisson-Nernst-Planck (PNP) equations on a hybrid grid system. The EDL interaction force calculated from numerical solution is compared with the one obtained from surface element integration (SEI) method.
A Model for Deposition of Metal Vapors From Multiple Targets on a Cylindrical Substrate
Authors: Singh Lakshmi , Kulkarni Anil K. , Singh Jogender
Published: July 2010

The paper addresses a challenging problem of developing technology for heat exchanger tubes embedded in ceramic composite matrix. Functionally graded composite tubes, made using physical vapor deposition (PVD) process, are required to have diffusion barrier layers, withstand high temperature, and be impermeable to hydrogen. The work addresses mathematical modeling of the deposition of metallic vapors from multiple targets on a cylindrical substrate to simulate the PVD process in manufacturing such tubes. Materials used for the deposition are Molybdenum and Niobium because they have shown good formability, strength, toughness and ductility over a wide range of temperatures. Commercially available software FLUENT was used to model the process. Prediction of condensation of vapors from metal ingots occurs in varying proportion along the circumference of the tube, resulting in submicron layers of different materials of varying thicknesses being ingrained into each other. Results are presented for patterns of materials showing continuously changing relative concentration of deposited metals over a stationary and rotating cylindrical substrate.
Somatic Value in Mechanical Products: Machines as Interactive Media
Authors: Fukuda Shuichi
Published: July 2010

This paper points out the importance of machines as tangible and substantial media for our customers to interact with the outer world. As the world is getting more and more globalized, diversified and complex, and situations are changing more frequently and extensively, it becomes harder and harder for designers to foresee operating conditions. Therefore design is changing quickly from traditional designer-centric to user-centric. It is a user who can understand the current situation and solve the imminent problem. Thus, the role of a machine is changing from a tool to a partner which helps a user understand the situation and solve the problem together. Although traditional role of machines has been primarily an actuator, its role as a sensing media is quickly increasing. Traditional product development has been one way and it is producer-driven, regarding customers as being very passive and just as consumers or users. But customers are very active and creative. The tangible and substantial feature of mechanical products has advantages in satisfying our customers’ needs for creativity and customization of our products to adapt to their needs and tastes and furthermore in creating experience and stories for them, which will add increased value, if not only product value but also process value is considered. To realize such goals, mechanical engineering should introduce more pragmatic approaches in addition to the current rational approach.
Application of Advanced Constitutive Models to the Simulation of Machining
Authors: Miller David A. , Chen Cameron K.
Published: July 2010

Advanced constitutive models have long been used to describe plastic material response at high strains and high strain rates. These models include the Johnson-Cook, Zerrelli-Armstrong and Material Threshold Stress (MTS) formulations, each with a separate fidelity. The constitutive parameters for these complex models are commonly identified using laboratory techniques such as quasi-static load frames at room and elevated temperatures, Split Hopkinson Pressure Bars (SHPB) in tension and compression, gas guns, and Taylor impact cylinders. However, while the models are able to adequately describe material response under high strain and high strain rate, the loadings are all uniaxial in nature. The ability of these constitutive models and parameters to describe a different dynamic loading event, namely shear dominated machining, has not been thoroughly investigated. This work will develop numerical simulations applying multiple constitutive models with material parameters experimentally determined for fully annealed copper samples. Ultimately, the machining simulation will be compared with high fidelity experimental machining data. The utility of this research extends to the fundamental questions that surround the machining process, such as tool forces, surface damage, precision and quality.
Joint Use of Traveling Wave Dielectrophoresis and AC-Electroosmosis for Particle Manipulation
Authors: Loire Sophie , Mezic Igor
Published: July 2010

Joint effect of traveling wave dielectrophoresis and AC electroosmotic fluid flow is used to sort bacteria from other particles and increase the bacteria output concentration in a microfluidic device. The device consists of a thin and long rectangular channel with two interdigitated electrode arrays, one at the bottom and one at the top of the channel, that are used to generate a nonuniform electric field. A four-phase signal at high frequency superposed on a low frequency signal is applied. At the end of the channel, the fluid is collected in two outputs: the bacteria are collected on one side and fluid without bacteria is collected on the other side. We have previously demonstrated a method to optimize cell separation using multiple frequency dielectrophoresis. The device presented here illustrates a novel use of multiple frequencies that permits the combined use of traveling wave dielectrophoresis and AC electroosmotic fluid flow.
Using the Fuzzy Method to Evaluate Manufacturing Productivity
Authors: Niu Jiping , Dartnall John
Published: July 2010

This paper introduces a useful method for improvement of the time forecasting of production lines operating at full speed production time (FSPT) and dealing with uncertain time losses. The full speed production time is a major index of the production line’s performance because it enables direct evaluation of production line output. This measure is called as overall equipment effectiveness (OEE). The fixed theoretically available hours minus time losses such as holidays, broken equipment and raw materials or labor shortages give us the production lines’ full speed production time. The waterfall chart model (WCM) improves the measurement of FSPT and can thereby help decision-makers to evaluate OEE. Unfortunately, there are many uncertain and imprecise factors operating. The fuzzy method can be used to reduce the degree and effect of uncertainty and imprecision [1]. We therefore introduce fuzzy theory into our WCM chart. This will assist decision makers in evaluating uncertainty and imprecision and obtain improved OEE measurements as well as producing better production plans and master production schedules [2].
An Integration of Micropump and Micromixer
Authors: Dinh Thien X. , Ogami Yoshifumi
Published: July 2010

In this paper, an one-layer valveless micropump which can work as a micromixer is numerically studied. The micropump consists of a pump chamber, a neck channel, an outlet channel which is perpendicular with the two opposite inlet channels. A side of the pump chamber is enclosed by a vibrating diaphragm which deforms volume of the pump chamber with time, then excites the flow from the inlet to the outlet of the pump. The attained flow rate at the outlet shows the advance of the present micropump in comparison with conventional nozzle-diffuser micropumps. The mixing performance of the devices is studied by Poincare map technique. It is observed that the mixing is enhanced with an inclined rib in the neck channel.
Design of Fiber-Reinforced Composite Tubes as Energy Absorption Element
Authors: Yang Y. , Terada S. , Okano M. , Nakai A. , Hamada H.
Published: July 2010

As an energy absorption member, fiber-reinforced composites (FRPs) are more favorable because they are light in weight and possess better energy absorption capabilities as compared to their metal counterparts. However, the energy absorbing mechanisms of FRP are complicated owning to the multi-micro fractures. Therefore, in this study, the designs of FRP tubes were carried out with considerations directed at the energy absorbing mechanisms. Two methods based on the design of the energy absorbed by bending of the fronds (Ubend) and the energy absorbed by fiber fractures (Uff) are concentrated. Here the bending behavior of frond can be considered as the bending beam by an external force. And it is found that Ubend is affected directly by the inertia moment I, which is affect by the geometry. Therefore, FRP tubes were fabricated to have a geometry combined with a bigger I. Additional, in order to get more fiber fractures to get an increased Uff, the design of bending stress, σ, was carried out. FRP tubes bending towards one side only rather than two sides are proposed to get bending fronds with a double thicker thickness, which in turn led to high stresses, many fiber fractures and high energy absorption.
Improved Fabrication of an Integrated Electromagnetic Second Stage Microactuator for a Hard Disk Recording Head
Authors: Saalfeld Henry , Dinulovic Dragan , Gatzen Hans H.
Published: July 2010

Key mechanical requirements for advanced Hard Disk Drive (HDD) recording heads are a minimal flying height and a perfect track following. By applying Micro Electro-mechanical Micro Systems (MEMS) technology, a Slider with an Integrated Microactuator (SLIM) enabling both in a cost competitive way was created. This paper describes the fabrication process for the system’s electromagnetic microatuator and emphasizes the technology enhancements achieved after a process redesign.
Extending the Capabilities of Hertz Equation Through Theoretical and Experimental Method
Authors: Darji P. H. , Vakharia D. P.
Published: July 2010

Contact analyses have been conducted over more than one century starting with Hertz who analyzed normal frictionless elastic contact between half-spaces with small deformation. The phenomenon of two surfaces in contact is important in the field of tribology and has been studied my many researchers. Hollow roller bearings find wide applications owing to their lower inertia, better radial stiffness and cooler running. The preloading of the rollers ensures many superior operating characteristics such as higher radial stiffness, rotational accuracy and higher speed capability. For hollow roller method is available for the calculation of contact width and contact stresses and all other important terminologies which are available for the solid roller. This paper presents a numerical and experimental analysis of the contact interaction between two elastic bodies “Cylinder and Flat”. In the numerical analysis Hertz theory is used to determine contact width for elastic contact. Experimental investigation has been performed by footprint method which is used to analyze a real contact area between two bodies for applied loading conditions. A comparison with the numerical data is given to validate the experimental procedure. The test results are almost similar and very close with the numerical data. Using this experimental method elastic contact between hollow cylinder and flat has been studied. Finally in the present work modified Hertz equation was developed for the calculation of half contact width for hollow cylinder and cylinder/flat body contact.