bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prediction of contact surface temperature between rough sliding bodies – numerical analysis and experiments
Authors: Ray Sudipto , Roy Chowdhury S.K. 
Published: August 2011

PurposeThe paper's aim is to predict numerically the contact temperatures between two rough sliding bodies and to compare with the experimental results.Design/methodology/approachAn elastic contact algorithm is used to analyze the normal contact between two nominally smooth surfaces. The algorithm evaluates real contact area using digitized roughness data and the corresponding contact pressure distribution. Using finite element method a steady state 3D temperature distribution at the interface between the sliding bodies is obtained. Using infrared (IR) imaging technique, experiments were carried out to measure the contact temperature distribution between rough rubbing bodies with a systematic variation of surface roughness and operating variables.FindingsContact temperature distributions over a wide range of normal load, sliding velocity and surface roughness have been obtained. It was seen that the maximum contact temperature expectedly increases with surface roughness (Sa values), normal load and sliding velocity. The results also indicate that the “hot spots” are located exactly at the positions where the contact pressures are extremely high. Temperatures can be seen to fall drastically at areas where no asperity contacts were established. The temperature contours at different depths were also plotted and it was observed that the temperatures fall away from the actual contact zone and relatively high temperatures persist at the “hot spot” zones much below the contact surface. Finally it is encouraging to find a good correlation between the numerical and experimental results and this indicates the strength of the present analysis.Research limitations/implicationsExperimental accuracy can be improved by using a thermal imaging camera that measures emissivity in situ and uses it to find the contact temperature. The spatial resolution and the response time of the camera also need to be improved. This can improve the correlation between numerical and experimental results.Practical implicationsOne of the major factors attributed to the failure of sliding components is the frictional heating and the resulting flash temperatures at the sliding interface. However, it is not easy to measure such temperatures owing to the inherent difficulties in accessing the contact zone. Besides, thermal imaging techniques can be applied only with such tribo‐pairs where at least one of the contacting materials is transparent to IR radiation. In practice, such cases are a rarity. However, the good correlation observed between the numerical and experimental results in this work would give the practicing engineer a confidence to apply the numerical model directly and calculate contact temperatures for any tribo‐material pairs that are generally seen around.Originality/valueA good correlation between the numerical and experimental results gives credence to the fact that the numerical model can be used to predict contact temperatures between any sliding tribo‐pairs.
The wear behaviour of duplex treated AISI 5140 steel
Authors: Totik Yasar , Alsaran Akgun , Celik Ayhan , Efeoglu Ihsan 
Published: August 2011

PurposeThis work aims to investigate the wear behavior of manganese phosphate coating on plasma nitrided AISI 5140 steel.Design/methodology/approachPrior to manganese phosphate coating, plasma nitriding of substrates was performed at gas mixture of 50 percent H2 and 50 percent N2, for the different treatment parameters. The structural, mechanical and tribological properties of the substrates were determined using hardness test, optical microscope, scanning electron microscopy , X‐ray diffraction and pin‐on‐disk tribotester. The wear behavior of untreated, nitrided and duplex treated substrates was evaluated under dry sliding conditions.FindingsThe results indicated that the duplex treatment improved the wear behavior. It was also observed that manganese phosphating of the nitrided substrates at low temperature (450°C‐2h‐N) resulted in a decrease of the wear rate and yielded a reduction in the friction coefficient by forming a transfer film at the counter face.Originality/valueThis study can be a practical reference and offers insight into the effects of duplex treating on the increase of wear resistance.
Robotic aircraft land at the Unmanned Show in the Mile High City
Authors: Bloss Richard 
Published: August 2011

PurposeThis paper aims to review the AUVSI Conference and show held in Denver, Colorado with emphasis on unmanned vehicles or service robots, their application on the ground, in the air and in the water.Design/methodology/approachIn‐depth interviews with exhibitors of unmanned vehicles and the providers of the technologies which are fundamental to their design and deployment. Also attendance at conference presentations.FindingsThe unmanned vehicle industry is largely driven by government requirements, both military and civilian. Unmanned service robots are also found in applications such as crop monitoring and fish school location at sea.Originality/valueUnmanned vehicles continue to address air ground and marine application needs where human safety is important. The vehicles continue to become more and more autonomous, ever better to address a wider range of application requirements.
High school student goes to class robotically
Authors: Bloss Richard 
Published: August 2011

PurposeThis paper seeks to build awareness of how telepresence or service robots are coming to the aid of students who might not otherwise be able to attend school in person or others who might need to be in two places at once.Design/methodology/approachDiscussions with the manufacturer and review of other coverage of the VGo telepresence or service robot in action.FindingsA service robot can really enhance the educational experience of students by allowing them to be “at school” when previously they were precluded from joining in with fellow students in the classroom and other school venues. The service robot gives humans the ability to independently see, hear, join in and move about the school or business situations when otherwise they might not be able to be present when they want or are needed somewhere else.Originality/valueA real example of how a service robot can permit a human to be in two places at once, such as a student who cannot go to school in person. It goes well beyond providing audio and visual linkage to also providing mobility.
Blending algorithm for position control with a hybrid actuator made of DC servomotor and brake
Authors: Gonenc Berk , Gurocak Hakan 
Published: August 2011

PurposeThis paper aims to present a hybrid actuator controller to obtain fast and stiff position response without any overshoot by blending input signals of a DC servomotor and a particle brake.Design/methodology/approachThe hybrid actuator controller has a module to estimate instantaneous changes in inertia and a blending algorithm that adjusts input signals to the motor and the brake so that together, as a hybrid actuator, they can achieve a fast, stiff position response without overshoot. The control logic implemented in the controller is derived from the kinematics of the system. For the blending algorithm, two separate cases are explored in which the user has the option to either utilize the full‐braking capacity or specify a safe deceleration limit for the system.FindingsThe blending algorithm enables the system to operate nearly twice as fast as the motor‐only case without any overshoot or oscillations. The controller can reject inertial load changes and significant external disturbances.Originality/valueSuch hybrid actuators along with the developed controller can be used in robotics and automation to increase the system accuracy and operational speed resulting in higher production rates. In addition, much stiffer haptic force feedback interfaces for virtual reality applications can be designed with smaller actuators. The blending algorithm provides considerable improvements and uses a physics‐based simple and easy‐to‐implement structure.
A new articulated leg for mobile robots
Authors: Gonzalez Rodriguez Antonio , Gonzalez Rodriguez Angel , Rea Pierluigi 
Published: August 2011

PurposeThe paper aims to present a new mechanical scheme for a leg to be included in legged vehicles that simplifies the control actuations along the stride.Design/methodology/approachThe scheme includes three four‐bar links grouped in two mechanisms. The first one decouples the vertical and horizontal foot movements. The second one produces a constant horizontal foot velocity when the corresponding motor is given a constant speed. A hybrid robot with wheels at the end of the hind legs has been simulated and constructed to validate the leg performance.FindingsThe gait control requires only five commands for the electronic cards to control the leg. Decoupling vertical and horizontal movements allows a more adequate selection of actuators, a reduction of energy consumption, and higher load capacity and robot velocity. Additional mechanical benefits, such as improved robustness and lower inertia, are obtained. The hind legs can also be articulated, allowing the robot to overcome an obstacle and to climb up and down stairs.Research limitations/implicationsA hybrid robot offers greater stability with respect to a legged robot. This way the lateral movement is not a concern, and therefore it has not been tested yet during the walking cycle.Originality/valueThis new scheme obtains a quasi‐Cartesian behaviour for the foot movement that drastically simplifies the control of the walking cycle. Although the decoupling between movements has already been obtained in previous configurations, these follow a pantograph structure and suffer from blocking problems when they are subject to lateral forces. These schemes were suitable for crab‐like gaits. The proposed leg moves according to a mammal‐like gait.
Who murdered strategy?
Authors: Speculand Robin 
Published: August 2011

PurposeIn business, the statistic that nine out of ten strategies fail has gone viral over the last couple of years. A prime reason for this is that leaders are under intense pressure in the current economic conditions to deliver on their strategy promises to shareholders. This article offers advice on how to execute a successful strategy within your organization.Design/methodology/approachGives advice for businesses that are trying to implement their next strategy, highlighting the importance of learning from past mistakes and making the right choices.FindingsLeaders must recognize that strategy implementation is extremely difficult and that they habitually underestimate its challenges. They perceive crafting strategy as the harder challenge and therefore by default blame the toughest area when it fails. Executing strategy, however, is just as tough as crafting the right strategy.Practical implicationsProvides tangible strategies that managers can adopt to enhance the effectiveness of their business strategy.Originality/valueThis article offers sage advice on how to implement a successful strategy, focusing on some of the trends that will start to appear over the next few years.
Interview with Paul Nunes and Tim Breene, authors of Jumping the S‐curve
Authors: by Juliet Harrison Interview 
Published: August 2011

PurposeThe purpose of this paper is to provide an interview with Paul Nunes and Tim Breene, authors of Jumping the S‐CurveDesign/methodology/approachThis briefing is prepared by an independent interviewer.FindingsEvery successful business eventually peaks. Greatness does not last. It falls prey to competition and commoditization, as well as obsolescence from the introduction of new technologies and innovations. And when a business's revenue growth stalls, only 7 percent ever go on to reclaim growth that is better than the growth of the market overall. The only solution is to jump to another growth curve, again and again.Practical implicationsPaul Nunes and Tim Breene take a look at the nature of the business “S‐curve”. Shaped like the first half of the bell curve, this curve is the characteristic depiction of how a new line of business ramps up, grows aggressively, and then ultimately flattens out. Through their interview, Paul and Tim give practical advice on what businesses should be doing in order to prepare for their next “S‐curve”.Originality/valueThe accelerating pace of business is forcing more top management teams to manage both their current successful business and their future business simultaneously. In the past, managers could often wait until the current business was firmly established, or even beginning to show signs of decline, before starting on the next. No longer. In this interview, Nunes and Breene highlight some of the most important disruptors emerging today, including cloud computing and sustainability, which are affecting companies in all industries, offering advice to companies wanting to take the lead in their own reinvention.
Shock wave simulations using Sinc Differential Quadrature Method
Authors: Korkmaz Alper , Dağ İdris 
Published: August 2011

PurposeThis paper aims to present a numerical solution of non‐linear Burger's equation using differential quadrature method based on sinc functions.Design/methodology/approachSinc Differential Quadrature Method is used for space discretization and four stage Runge‐Kutta algorithm is used for time discretization. A rate of convergency analysis is also performed for shock‐like solution. Numerical stability analysis is performed.FindingsSinc Differential Quadrature Method generates more accurate solutions of Burgers' equation when compared with the other methods.Originality/valueThis combination, Sinc Differential Quadrature and Runge‐Kutta of order four, has not been used to obtain numerical solutions of Burgers' equation.
Probabilistic evaluation of seismic liquefaction potential in field conditions
Authors: Jafarian Yaser , Baziar Mohammad H. , Rezania Mohammad , Javadi Akbar A. 
Published: August 2011

PurposeIn this paper, the peak kinetic energy density (KED) of soil particles during earthquake excitation is used as an intensity measure for the evaluation of liquefaction potential under field conditions. The paper seeks to discuss this measure.Design/methodology/approachUsing centrifuge tests data, it is shown that seismic pore water pressure buildup is proportional to cumulative KED at a particular soil depth. Linear relationships are found between cumulative kinetic energy and corresponding cumulative strain energy. To consider the effect of soil amplification, several equivalent linear ground response analyses are performed and the results are used to derive an equation for depth reduction factor of peak kinetic energy density. Two separate databases of liquefaction case histories are used in order to validate the proposed model. The performance of the proposed model is compared with a number of commonly used shear stress‐based liquefaction assessment methods. Finally, the logistic regression method is employed to obtain probabilistic boundary curves based on the present model. Parametric study of the proposed probabilistic model is carried out to verify its agreement with the previous methods.FindingsIt has been shown that the kinetic energy model works satisfactorily in classifying liquefied and non‐liquefied cases compared with the existing recommendations of shear stress‐based criterion. The results of the probabilistic kinetic energy model are in good agreement with those of previous studies and show a reasonable trend with respect to the variations of fines content and effective overburden pressure. The proposed model can be as used an alternative approach for assessment of liquefaction potential.Originality/valueThese findings make a sound basis for the development of a kinetic energy‐based method for assessment of liquefaction potential.
Tin whisker analysis of Toyota's electronic throttle controls
Authors: Sood Bhanu , Osterman Michael , Pecht Michael 
Published: August 2011

PurposeThis paper aims to present the results of physical analysis that was conducted on Toyota's electronic engine control system including accelerator pedal position sensors (APPSs). The paper overviews the analyses and focuses on the discovery of tin whiskers found in the accelerator pedal assembly, which are an electrical failure concern.Design/methodology/approachAnalytical techniques such as X‐ray fluorescence spectroscopy, scanning electron microscopy and energy dispersive spectroscopy are utilized to present a construction analysis of the APPS.FindingsThe use of a tin finish in the APPS is a cause for concern. Tin finishes are known to produce metal whiskers that are conductive and capable of creating unintended current leakage paths. In the analysis, a significant number of tin whiskers were found.Research limitations/implicationsThe methodology discussed in this paper can be implemented to inspect for tin whiskers in the APPSs.Originality/valueThe paper begins a construction analysis of different parts of the Toyota engine control module and APPSs and then moves on to highlight electronics design issues that can comprise the engine control system and cause unintended consequences.
Eight key HDI design principles
Authors: Holden Happy , Pfeil Charles 
Published: August 2011

PurposeHigh‐density interconnect (HDI) continues to be the fastest growing segment of the printed circuit board (PCB) market. The purpose of this paper is to discuss the differences in designing HDI compared to conventional PCB multilayers. This is important for the challenging aspects of very high‐speed electronics that require care to control signal integrity and power integrity.Design/methodology/approachEight new design principles were studied and illustrated with emphasis on how these differ from conventional PCB design.FindingsHDI implementation can be improved 2X to 4X by employing these new design principles. Densities from 6‐12 in. per sq. inch to 18‐48 in. per sq. inch have been reported. Design time reductions of 50 percent and cost reductions of 30 percent were also seen.Research limitations/implicationsThis work was focused on the basic design principles and does not address electronics design automation tools or specific design steps. PCB design is a complex activity and readers are encouraged to obtain and use the references cited.Originality/valueThe paper describes various design and layout procedures that the authors have learned over the last 29 years involved in printed circuit design and fabrication. These principles can be combined with other innovations to enable a much more beneficial use of HDI technologies.
A brief history and recent developments in day‐of‐the‐week effect literature
Authors: Philpot James , Peterson Craig A. 
Published: August 2011

PurposeThe purpose of this paper is to provide a brief review of pre‐2003 work on the weekend effect and then discuss how recent selected work has extended our knowledge of the subject.Design/methodology/approachResults of recently published studies are organized and summarized by research question and outcomes.FindingsWhile early literature found a fairly consistent weekend effect, with positive returns on Fridays and negative returns on Mondays, more recent research shows the effect moving to other days, reversing or vanishing.Research limitations/implicationsWhile it is difficult to compare studies made across different time periods, the direction of present research gives insight into how markets are adjusting to the weekend effect anomaly.Practical implicationsInvestors may find it very hard to adequately identify a trading strategy based on current research.Originality/valueThis work conveniently synthesizes and presents current research findings from a variety of published sources.
Numerical simulation of electrical engineering devices
Authors: Pantelyat M. , Shulzhenko M. , Matyukhin Y. , Gontarowskiy P. , Dolezel I. , Ulrych B. 
Published: August 2011

PurposeThe paper seeks to present a methodology of computer simulation of coupled magneto‐thermo‐mechanical processes in various electrical engineering devices. The methodology allows determining their parameters, characteristics and behaviour in various operation regimes.Design/methodology/approachThe mathematical model consisting of three equations describing magnetic field, temperature field and field of mechanical strains and stresses (or thermoelastic displacements) is solved numerically, partially in the hard‐coupled formulation.FindingsThe methodology seems to be sufficiently robust, reliable and applicable to a wide spectrum of devices.Research limitations/implicationsAt this stage of research, the hard‐coupled formulation of thermo‐mechanical (or thermoelastic) problems is still possible only in 2D.Practical implicationsThe methodology can successfully be used for design of numerous machines, apparatus and devices from the area of low‐frequency electrical engineering ranging from small actuators to large synchronous generators.Originality/valueComplete numerical analysis of coupled magneto‐thermo‐mechanical phenomena in electrical devices.
Domains of validity of quasistatic and quasistationary field approximations
Authors: Steinmetz Thorsten , Kurz Stefan , Clemens Markus 
Published: August 2011

PurposeThe paper aims at proposing a uniform and demonstrative description of two well‐known and widely used approximations of slowly time‐varying electromagnetic fields, i.e. the electro‐quasistatic and the magneto‐quasistationary approximation to Maxwell's equations.Design/methodology/approachUnder both approximations, the orders of magnitude of the relative errors of the dominant fields are analyzed by using three characteristic time constants. These time constants are determined by considering the material properties, the characteristic length scale and the characteristic time scale.FindingsLimiting curves which show the domains of applicability of the two approximations are retrieved from the estimation of their relative errors. The relation between the domains of validity of the electro‐quasistatic and magneto‐quasistationary approximations was found and depicted in a combined diagram.Research limitations/implicationsThe study is restricted to slowly time‐varying electromagnetic fields. Heuristic and local estimates based on local material properties were used for the analysis. Rigorous estimations of the errors (e.g. also considering the field problem's topology) of the magneto‐quasistationary approximation are already known in the literature. A rigorous estimation of the error of the electro‐quasistatic approximation is, therefore, suggested for future research.Originality/valueThe combined diagram showing the domains of validity of both approximations considered here in a uniform way is novel. It gives rise to an intuitive and easily accessible understanding of their applicability.