bluuebunny/crossref_metadata_2025 huggingface dataset:
The Daily Events and Emotions of Master’s‐level Family Therapy Trainees in Off‐campus Practicum Settings
Authors: Edwards Todd M. , Patterson Jo Ellen
Published: June 2012

The Day Reconstruction Method (DRM) was used to assess the daily events and emotions of one program’s master’s‐level family therapy trainees in off‐campus practicum settings. This study examines the DRM reports of 35 family therapy trainees in the second year of their master’s program in marriage and family therapy. Four themes emerged from the results: (i) Personal contact with peers‐in‐training engenders the most positive emotions during practicum; (ii) Trainees experience more positive emotions during therapy with families and couples in comparison with therapy with individuals; (iii) Positive affect increases over the course of a student’s practicum year; and (iv) Trainees experience less positive affect in individual supervision in comparison with most other training activities. Flow theory offers guidance for supervisors helping trainees face developmental challenges of clinical training.
Effect of diabetes mellitus on corneal biomechanics and measurement of intraocular pressure
Authors: Scheler Annabelle , Spoerl Eberhard , Boehm Andreas G.
Published: June 2012

Purpose:  To determine whether corneal hysteresis (CH) and corneal resistance factor (CRF) are altered in diabetes and whether these parameters are related to HbA1c.

Methods:  One randomly chosen eye of 35 healthy subjects and 31 patients with diabetes was examined. Patients with diabetes were divided into group 1 with HbA1c <7% (n = 14) and group 2 with HbA1c ≥7% (n = 17). CH and CRF were measured using ocular response analyzer (ORA); central corneal thickness (CCT) using ultrasound pachymetry; increased intraocular pressure (IOP) using Goldmann tonometer (IOPGAT), Pascal dynamic contour tonometer (IOPpasc), and ORA (IOPcc). As CH and CRF are dependent on IOP and CCT, they were adjusted for IOP and CCT resulting in CHcorr and CRFcorr.

Results:  Mean HbA1c was 5.44 ± 0.46% in healthy subjects, 6.00 ± 0.78% in diabetic group 1, 8.58 ± 2.44% in group 2. CHcorr (p = 0.071) and CRFcorr (p = 0.067) were not statistically significantly different between healthy subjects and diabetic group 1, but significantly lower in healthy subjects compared to diabetic group 2 [CHcorr (p = 0.031), CRFcorr (p = 0.029)]. IOPpasc (p = 0.012), IOPGAT (p = 0.032) and HbA1c (p = 0.0001) were statistically significantly different between healthy subjects and all patients with diabetes (groups 1 + 2), but not age, sex and CCT. Over all patients with diabetes, CHcorr (p = 0.012, R2 = 0.197) and CRFcorr (p = 0.008, R2 = 0.217) were correlated to HbA1c but not in healthy subjects [CHcorr (p = 0.931, R2 = 0.0001), CRFcorr (p = 0.837, R2 = 0.001)].

Conclusion:  In poorly controlled diabetics, CHcorr and CRFcorr are significantly higher compared with those of the healthy subjects and patients with well‐controlled diabetes. In diabetes, CHcorr and CRFcorr are correlated to HbA1c, suggesting that the biomechanical properties of the cornea are altered depending on the glucose control.
Macular thickness predictive of visual field sensitivity in ischaemic optic neuropathy
Authors: Papchenko Taras , Grainger Brian T. , Savino Peter J. , Gamble Greg D. , Danesh‐Meyer Helen V.
Published: June 2012

Purpose:  To investigate the ability of optical coherence tomography (OCT) parameters of macular thickness (MT) and peripapillary retinal nerve fibre layer (RNFL) thickness to differentiate eyes with nonarteritic anterior ischaemic optic neuropathy (NAION) from uninvolved eyes and to identify the relationship between macular and RNFL parameters and visual field sensitivity (VFS).

Methods:  Thirty patients with unilateral NAION participated in a prospective observational cross‐sectional study. Patients underwent Humphrey visual field (SITA Standard 24‐2, HVF) testing and OCT to measure MT and RNFL. The contralateral uninvolved eye was used as controls. Areas under the receiver operating characteristic curves (AUROCs) of MT and RNFL for discriminating NAION from control eyes were also determined. The prespecified outcome measure was the correlation between RNFL, MT and mean deviation (MD).

Results:  Average RNFL and MT were thinner in NAION eyes: 72.8 μm versus 98.9 μm (p < 0.0001) and 231.9 μm (SD, 21.4) vs. 251.1 μm (SD, 14.8; p = 0.0001), respectively. The largest AUROCs were for average MT (0.87) and average RNFL thickness (0.88). Overall, macular parameters showed stronger correlation with VFS than RNFL parameters. The highest correlation was average MT (0.71; p < 0.0001) followed by RNFL parameter nasal quadrant RNFL (0.40; p = 0.030).

Conclusion:  Both MT and RNFL show strong correlations with level of VFS in NAION. Macular thickness showed more robust correlations with VF and provides strong surrogate marker of the level of damage in NAION.
Subjective sleep quality in lung cancer patients before and after chemotherapy
Authors: Zarogoulidis Paul , Steiropoulos Paschalis , Perantoni Eleni , Archontogeorgis Konstantinos , Eleftheriadou Ellada , Porpodis Konstantinos , Charpidou Anna G. , Angelopoulou Christina , Nena Evangelia , Zarogoulidis Konstantinos , Tsara Venetia
Published: June 2012

Background:  Sleep disturbances, such as difficulty in falling asleep, maintaining sleep, poor sleep efficiency, early awakening, and excessive daytime sleepiness, are common in patients with cancer. The aim of this study was to evaluate sleep characteristics in newly diagnosed lung cancer patients before and after three months of chemotherapy treatment.

Methods:  Forty‐nine patients with lung cancer, without brain metastasis, were included. Anthropometric and disease characteristics were collected. Upon diagnosis and after three months, a polysomnographic examination was conducted and the patients completed the Epworth Sleepiness Scale (ESS), the Pittsburgh Sleep Quality Index (PSQI), the Fatigue Severity Scale (FSS) and the Medical Research Council (MRC) dyspnoea scale.

Results:  Before chemotherapy, the mean PSQI score was 7.1 ± 4, the FSS score was 3.92 ± 2, and the ESS score was 6.8 ± 4. The MRC score was low at 1.6 ± 1.1. A significant correlation between FSS and global PSQI was revealed (r = 0.424, P < 0.01), as well as with several of the PSQI components. After chemotherapy, no statistically significant change was observed in the PSQI (mean: 6.6 ± 4.5, t‐score: 0.784, P = 0.438), or the FSS score (4.4 ± 2.2, t‐score: −1.375, P = 0.177). Sleep efficiency was significantly reduced (P = 0.008), without any change in the distribution of sleep stages.

Conclusion:  The perception of sleep quality is poor among newly diagnosed lung cancer patients and is correlated with fatigue. After chemotherapy, self‐reported sleep impairment is present and sleep efficiency is reduced, without significant change in sleep architecture.
Gear Transmission Density Maximization
Authors: Kapelevich Alexander L. , Ananiev Viacheslav M.
Published: June 2012

Maximization of the gear transmission density presents an important task. It allows to increase the output torque within given dimensional constrains that is critical, for instance, in racing gearboxes, or to reduce size and weight of aerospace gear drives. It can also lead to reduced costs for automotive and consumer product gear trains, etc. There are several ways to increase gear drive load capacity, including advanced design, materials, and technologies. This paper presents an approach that allows optimizing gearbox kinematic arrangement and gear tooth geometry to achieve high gear transmission density. It introduces dimensionless gearbox volume functions, which can be minimized by the internal gear ratio optimization. Different gearbox arrangements are analyzed to define a minimum of the volume functions. Application of the asymmetric gear tooth profiles power density maximization is also considered.
Mechanical Design and Fabrication of a Low-Cost, Modular, Mobile Gantry for Non-Invasive Medical Applications
Authors: Gafford Joshua , Schneider Johannes
Published: June 2012

This paper details the design and development of a low-cost, human-sized, mobile, mechanical gantry for potential use in non-invasive medical imaging procedures. The gantry features two independently-actuated aluminum rings, each capable of supporting a variety of different medical instruments. The gantry described herein was designed to integrate with an existing flat-panel Volume Computed Tomography (CT) scanner to create a hybrid Optical Tomography/Computed Tomography setup to facilitate image coregistration. However, the gantry also has potential utility in MRI coregistration, low-cost CT, laser therapy, and any other applications that necessitate precise, stepwise 360-degree rotary motion around a patient. The total production cost for the gantry, including stock, labor, and assembly, was ∼$15,000. Preliminary tests show that the gantry in open-loop has a positional repeatability to within 70 μm.
Structural Topology Optimization for Forced Vibration Problem Using Level Set Method
Authors: Shu Lei , Wang Michael Yu , Fang Zongde , Ma Zhengdong
Published: June 2012

For the purpose of structure vibration reduction, a structural topology optimization for forced vibration problem is proposed based on the level set method. The objective of present study is to minimize the frequency response at the specified points or surfaces on the structure with an excitation frequency or a frequency range, subject to the given amount of the material over the admissible design domain. The sensitivity analysis with respect to the structural boundaries is carried out, while the X-FEM is employed for solving the state equation and the adjoint equation. The optimal structure with smooth boundaries is obtained by the level set evolution with advection velocity, derived from the sensitivity analysis and the optimization algorithm. A number of two-dimensional numerical examples are presented to demonstrate the feasibility and effectiveness of the proposed approach.
A Highly Accurate Beam Finite Element for Curved and Twisted Helicopter Blades
Authors: Skladanek Yan , Cranga Paul , Ferraris Guy , Jacquet Georges , Dufour Re´gis
Published: June 2012

Blade optimization is more than ever a crucial activity for helicopter manufacturers, always looking for performance improvements, noise reduction and vibratory comfort increase. Latest studies have led to design new blade concepts including a double swept plan shape, an evolutionary and increased twist angle at the tip and a new layout for internal components like roving spars. Such blades exhibit a highly coupled behavior between torsion, longitudinal and bending motions that should be accurately modeled for predictive numerical tools. In this research a highly accurate beam finite element is formulated in the rotating frame to improve the static deformation calculation under aerodynamic and centrifugal loads and thus enhance dynamic and stability analysis usually performed for a helicopter development. Numerical and experimental investigations are performed to demonstrate the model reliability both for academic beams with extreme shape and for actual blade design.
Number Enumeration of Planar Pin-Joined Driving Mechanisms
Authors: Mitrouchev Peter , Maffray Fre´de´ric , Amri Slim , Nafiss Abdelghafour , Dahan Marc
Published: June 2012

This paper deals with the development of a new method for the morphological number enumeration for planar pin-jointed driving mechanisms applied in robotic design. The method is based on linkage graph presentation by using geometrical symmetries of kinematic chains and combinatorial analysis. The restricting criteria being the position of: the frame, the end-effector and the actuators (motors) of the robot, different cases of symmetries for planar pin-jointed driving mechanisms of mobility 1 and 2 are addressed. New expressions for calculating the number of different possibilities to position the frame, the end-effector and the actuators in a mechanism are presented, thus reducing the number of the possible solutions by avoiding those that are isomorphic. A further consequence of the present work is the ability for it to be extended to mechanisms with three degrees of mobility and more.
Study of the Sequential Constraint-Handling Technique for Evolutionary Optimization With Application to Structural Problems
Authors: Motte Damien , Nordin Axel , Bja¨rnemo Robert
Published: June 2012

Engineering design problems are most frequently characterized by constraints that make them hard to solve and time-consuming. When evolutionary algorithms are used to solve these problems, constraints are often handled with the generic weighted sum method or with techniques specific to the problem at hand. Most commonly, all constraints are evaluated at each generation, and it is also necessary to fine-tune different parameters in order to receive good results, which requires in-depth knowledge of the algorithm. The sequential constraint-handling techniques seem to be a promising alternative, because they do not require all constraints to be evaluated at each iteration and they are easy to implement. They nevertheless require the user to determine the ordering in which those constraints shall be evaluated. Therefore two heuristics that allow finding a satisfying constraint sequence have been developed. Two sequential constraint-handling techniques using the heuristics have been tested against the weighted sum technique with the ten-bar structure benchmark. They both performed better than the weighted sum technique and can therefore be easy to implement, and powerful alternatives for solving engineering design problems.
Study of Uniform Heating and Efficiency of Paper Mill Drying Procedures
Authors: Greely Scott , Bennett Grover , Amano R. S. , Guntur Krishna S. , Singh Shyam
Published: June 2012

The Paper Mill Project goal is to improve upon the uniform heating of a continuous paper sheet flowing across a heat source for the purpose of drying the paper. The project tests different porous media to achieve uniform heat distribution across the paper. Existing designs overheat the paper to overcome the uneven heat distribution caused by uneven flow velocities; current designs also achieve low overall efficiency. This project attempts to test the effect porous media has on creating even heat distributions across the paper sheet, and which type of porous media achieves the greatest overall efficiency. This project was conducted in two phases; the first phase tests the different porous medium drying a single sheet conveying at two different sheet velocities. The second phase tested the different porous medium drying four stationary strips of paper for a length of one minute.
A Thermoacoustic Engine Design
Authors: Wind Evan , Wattenford Dave , Sisneros Paul , Amano R. S. , Mohan Das Pradeep Mohan
Published: June 2012

This paper discusses basic standing wave theory as it relates to thermoacoustics as well as the design, construction, and testing of a simple thermoacoustic engine based upon these principles. This paper covers the design, construction, and testing of a proof-of-concept engine to demonstrate the possibility of converting heat energy into mechanical energy via sound waves. A Soundhauss tube was constructed and tested to demonstrate the fundamental principles of acoustic resonance within a single closed-ended tube upon which the engine function is based. Fundamental frequency calculations are performed for the particular setup as well as stack design and thermal penetration depth calculations. With society’s current focus on human impact upon the environment, renewable sources of energy, and the inability for current energy grid systems to fulfill needs for remote and developing civilizations at feasible cost, the development of the Thermoacoustic Engine is a pursuit worth exploring. Thermoacoustic Engines harbor few or no moving parts, consist of simple components with low manufacturing overhead, and utilize 100% environmentally safe materials and gases. The engine essentially uses heat to create sound, and sound to create electricity or motion. The operational requirements are very lax which allows for a wide range of design possibilities. This relative simplicity of progression from source to output is what gives the engine its potential for mass adoption; particularly in areas conventional means of energy distribution have struggled to reach.
A Three-Dimensional Evacuation Simulation Using Digital Human Models With Precise Kinematic Joints
Authors: Kakizaki Takao , Urii Jiro , Endo Mitsuru
Published: June 2012

Disaster drills are important for minimizing the damage caused by earthquakes, floods, and fires. Therefore, mass-evacuation drills are considered to be an important obligation of schools and workplaces that employ several individuals. Moreover, for the validation of drill effectiveness as well as disaster prevention, the significance of mass-evacuation simulation has increased. In the present paper, a three-dimensional mass-evacuation simulation is first explained. The developed multi-agent-based simulation with a detailed three-dimensional building infrastructure uses a kinematic digital human model with precise human joints. Simulation of a mass-evacuation drill by high-school students agrees well with the results of actual drills. In addition, considering the transportation of badly injured persons during disasters, digital human motion sets of patients and transporters have been developed for critical evacuation simulation. Several examples have revealed the possibility of applying the extended simulation to evacuation from houses and hospitals.
An Information Technological Specification of Abstract Prototyping for Artifact and Service Combinations
Authors: Horva´th Imre , Rusa´k Zolta´n , Hernando Martin Eva , van der Vegte Wilhelm F. , Kooijman Adrie , Opiyo Eliab Z. , Peck David
Published: June 2012

Various early prototyping techniques have been proposed for specific purposes and products, for instance for user-centered design of software tools, or interface design of consumer durables. Our research focuses on the development of a comprehensive approach, called abstract prototyping, to support a rich and complete prototyping of artifact-service combinations (ASCs). In this paper we present the concept and implementation of abstract prototypes (APs) from an information system point of view, and discuss both the general information structure and the specific information constructs used in our approach. First, the main constituents of APs are identified. Then, formal definitions of the involved information constructs are introduced. Afterwards, the practical implementation of the information constructs is discussed. As an information processing activity, abstract prototyping decomposes to four stages: (i) aggregation of information about the innovated ASCs, (ii) compilation and testing of the technical contents for abstract prototype(s), (iii) demonstration of the abstract prototype(s) to stakeholders, and (iv) refinement of the contents towards a final abstract prototype. It is assumed that ideation and elaboration of the concepts of the new artifact-service combinations precedes and produces input for abstract prototyping. It is proposed that APs should demonstrate real life manifestation of all characteristic operation and interaction/use processes, including the operation of the conceptualized artifact-service combination, the actions of the human actors, and the happenings in the surrounding environment. This can be achieved through the inclusion and proper instantiation of the necessary information constructs in the APs. The real life processes established by the existence and operations of ASCs is modeled and represented by scenarios. The contents of the abstract prototype are designed and demonstrated taking the interests and needs of the stakeholders into consideration. Eventually, an abstract prototype consists of two main constituents, namely narration and enactment, which enable the presentation of the technical contents. The former conveys a story about the manifestation of the ASCs and highlights the accompanying processes, and the latter visualizes the components, actors, arrangements, procedures, and happenings involved in them. The presented approach of information content development has been tested in master graduation projects, certain cycles of PhD research, and a company orientated process innovation project. The follow up research focuses on the development of a dedicated tool for abstract prototyping, and on the validation of proposed development and application methodology in complex industrial cases.
Developing Interfaces for Interactive Product Visualization in Truly 3D Virtual Workspaces
Authors: Opiyo E. Z.
Published: June 2012

Three-dimensional (3D) visualization technologies are increasingly applied in visualization of virtual product models. Devices such as 3D glasses, head/helmet mounted displays (HMDs), stereo projectors and in some instances even some of the emerging visualization technologies including, for instance, holographic displays, swept volume displays and other volumetric displays are examples of technologies that can be used in visualization of virtual models of engineering products. These technologies allow viewers (i.e. in this case designers and engineers) to explore various aspects of products such as appearance or shape more aptly. 3D virtual product models are especially useful for activities that require space imagination such as evaluation of concepts, aesthetics review, assembly verification and ergonomics review. The problem, however, is that interactivity of most of the existing 3D visualization technologies is very limited. Therefore, this paper describes an attempt aimed at developing intuitive interaction methods for visualization of 3D product models in truly 3D visualization environment and at investigating how basic tasks such as selecting, rotating or moving 3D virtual object in 3D scene can be accomplished. A holographic display is used as a case study truly 3D visualization technology. Different interaction methods have been developed and user tests carried out to qualitatively evaluate the usability and suitability of these methods. Motion tracking is seen as a practical way for manipulating 3D product models in 3D workspace while spatial touch screen with tangible object and virtual menu is seen as a practical method for manipulating menu items. The paper also illustrates how these two interface methods can be used for performing certain basic interactive product visualization operations in 3D workspace.
Deformations and Stresses in Face-Hobbed Spiral Bevel Gears
Authors: Simon Vilmos V.
Published: June 2012

In this study an attempt is made to predict displacements and stresses in face-hobbed spiral bevel gears by using the finite element method. A displacement type finite element method is applied with curved, 20-node isoparametric elements. A method is developed for the automatic finite element discretization of the pinion and the gear. The full theory of the generation of tooth surfaces of face-hobbed spiral bevel gears is applied to determine the nodal point coordinates on tooth surfaces. The boundary conditions for the pinion and the gear are set automatically as well. A computer program was developed to implement the formulation provided above. By using this program the influence of design parameters and load position on tooth deflections and fillet stresses is investigated. On the basis of the results, obtained by performing a big number of computer runs, by using regression analysis and interpolation functions, equations for the calculation of tooth deflections and fillet stresses are derived.
Realization and Application Method of Mechanisms Motion Simulation in Virtual Assembly System
Authors: Zhang Zhixian , Liu Jianhua , Liu Yang
Published: June 2012

In recent years, physical simulation is a new trend of virtual assembly (VA) technology. As a part of physical simulation, mechanisms motion simulation is an important research topic. In order to realize the mechanisms motion simulation in VA system, we presented the realization and application method of mechanisms motion simulation in virtual assembly system combining the prototype system, Virtual Assembly Process Planning (VAPP). We described the bottom framework of VAPP system used for mechanisms motion simulation. Then based on the support of bottom platform, we studied the realization method of mechanisms motion simulation and apply mechanisms motion simulation to virtual assembly simulation via some technologies in VAPP system. Our research shows that, simulating mechanisms motion in VA system not only realizes the visualization of mechanism analysis and simulation, but also improves the ability of analysis of VA system effectively and extends the application range of VA system.
Kinematics of the (nS)-2SPU Wrist
Authors: Di Gregorio Raffaele
Published: June 2012

The majority of the manipulation tasks requires the motion of the end effector from an initial pose to a final one without particular conditions on the path. Thus, the reduction of the practicable paths between two any poses is a possible choice, exploitable at the design stage, for simplifying manipulator’s hardware. This choice is adopted in under-actuated manipulators. The (nS)-2SPU wrist is one out of the under-actuated parallel wrists this author proposed in a previous paper. Here, the kinematic analysis of this wrist is studied. Both its finite and its elementary kinematics are considered. It is shown that its control algorithms can be written by using simple closed-form formulas, which can take advantage from the wide literature on spherical four-bar linkages. And the demonstration that its singular configurations can be avoided more easily than the ones of the fully-parallel wrist is provided.
Blind Source Separation of a Single Channel Based on Repeated Independent Component Analysis
Authors: Leng Yong-gang , Chen Ting-ting , Pan Yue-ran , Lai Zhi-hui
Published: June 2012

Independent component analysis (ICA) is a kind of steady algorithm for the separation of blind source (BSS). However, there are three assumptions for the ICA application, one of which is that the number of test channels must be more than that of the signal sources. The limitation brings much inconvenience to practical signal acquisition and processing. In this paper, we propose a new method of repeated independent component analysis (Re-ICA) to realize the separation of blind sources. Under a single test channel, we can increase test channels by means of constructing virtual signal channels and use ICA repeatedly to separate every source signal in turn. Numerical simulation and signal processing of practical data acquisition by one single test-channel show that the proposed method is simple and feasible for operation, and is of great potential in engineering application.
Design a New Spherical Super Element to Static and Modal Analysis of Spherical Structures
Authors: Faghani Hamid , Ahmadian M. T.
Published: June 2012

Hollow Spherical Structures such as spherical pressure vessels are widely used in industries. Using faster numerical methods to solve these spherical problems has been one of the research interests in the last decade. Super elements are elements capable of producing the same accurate result in comparison with several conventional elements. In this paper, a new spherical super element is designed and implemented to study the static deformation and modal analysis of a spherical structure. In the static analysis mean of the inner radial displacements of the hollow structure under the internal pressure is evaluated, also performing the modal analysis, natural frequencies of the structure under the specified boundary condition are obtained. Findings are compared with those of conventional finite element methods and very good agreements are achieved. Using two spherical super element result the same displacement in conventional finite element with 2164 three dimensional brick elements.
Fall on Backpack: Damage Minimizing Humanoid Fall on Targeted Body Segment Using Momentum Control
Authors: Lee Sung-Hee , Goswami Ambarish
Published: June 2012

Safety and robustness will become critical issues when humanoid robots start sharing human environments in the future. In physically interactive human environments, a catastrophic fall is the main threat to safety and smooth operation of humanoid robots, and thus it is critical to explore how to manage an unavoidable fall of humanoids. This paper deals with the problem of reducing the impact damage to a robot associated with a fall. A common approach is to employ damage-resistant design and apply impact-absorbing material to robot limbs, such as the backpack and knee, that are particularly prone to fall related impacts. In this paper, we select the backpack to be the most preferred body segment to experience an impact. We proceed to propose a control strategy that attempts to re-orient the robot during the fall such that it impacts the ground with its backpack. We show that the robot can fall on the backpack even when it starts falling sideways. This is achieved by utilizing dynamic coupling, i.e., by rotating the swing leg aiming to generate spin rotation of the trunk (backpack), and by rotating the trunk backward to drive the trunk to touch down with the backpack. The planning and control algorithms for fall are demonstrated in simulation.
Numerical Analysis of the Band Excitation AFM Method: Examining the Characteristics of the Excitation Signals and the Corresponding Response Behavior at the Cantilever Tip
Authors: Kareem Adam U. , Solares Santiago D.
Published: June 2012

We present numerical simulations of a recently developed atomic force microscopy (AFM) technique known as the Band Excitation Method, developed by Jesse et al. [2007 Nanotechnology 18 435503]. With this technique an AFM microcantilever is simultaneously excited and the response measured over a continuum band of frequencies. The purpose of this work is to introduce an analytical model providing insight into the dynamics of the Band Excitation Method, which can help in the translation of the acquired signals into sample properties. As an initial step we examine the cantilever response to two distinct excitation signals, the chirp and sinc functions, both of which have uniform frequency content, differing only in the phase content.
Effects of Bearing Preload, Oil Volume and Operating Temperature on Axle Power Losses
Authors: Xu Hai , Singh Avinash , Kahraman Ahmet , Hurley Joshua , Shon Sam
Published: June 2012

In order to boost the fuel economy of their vehicles, automotive OEMs and suppliers have been investigating a range of options from alternate vehicle propulsion systems down to optimized component level technologies. A rear axle differential with a hypoid gear set is one of the least efficient drive train components, and as such, provides unique opportunities for improvements. It has therefore attracted significant attention from researchers to reduce the power losses. Both loaded and unload power losses have been studied before and found to vary significantly with load and speed conditions. This paper will focus on the effects of the axle pinion bearing preload, axle gear oil levels and operating temperatures on axle power losses during the fuel economy driving cycles where both axle load and speed vary significantly. In this paper, power loss measurements from experiments conducted on an automotive rear drive axle on a dedicated dynamometer will be presented. Tests were conducted under a range of speed and load conditions that were developed from EPA fuel economy driving cycles. Both urban and highway cycles were included in the tests. Separate tests were conducted for unloaded spin losses and loaded power losses. The tests were conducted at a few different controlled levels of gear oil operating temperatures, gear oil volumes and pinion bearing preloads, and their influence on power losses were quantified. The measured power losses, at a matrix of load and speed conditions provide a series of power loss maps as a function of gear oil operating temperature, oil volume, and bearing preload. Using these power loss maps, the overall axle efficiency or power loss during any driving cycle can be quantified by integrating the instantaneous power losses as the axle goes through the driving cycles. Similar maps can be created for other influences and the proposed procedure can be utilized to quantify their influences on a given driving cycle. Results from this study indicate that with the combination of appropriate preloads, gear oil volume and temperature control, axle efficiency can potentially be improved by roughly 3% in the tested axle.
In-Vitro Diagnosis of Colon Cancer Using Bio-Functionalized Magnetic Nanoparticles
Authors: Hong Chin-Yih , Yang Shieh-Yueh , Huang K. W. , Horng Herng-Er , Yang Hong-Chang
Published: June 2012

The popular bio-marker for colon cancer is carcinoembryonic antigen (CEA). By conjugating anti-CEA onto magnetic nanoparticles, CEA can be specially labeled and detected by measuring magnetic signals via immunomagnetic reduction (IMR). The low detection limit and detection range of IMR on CEA are investigated. The results are compared with those by using the existing assay, such as enzyme-linked immunosorbent assay (ELISA). It is evidenced that IMR has sensitivity much higher than that of ELISA. The low detection limit is below the normal level of CEA concentration of clinic practice and is suitable for early-stage in-vitro diagnosis for colon cancer. Furthermore, the dynamic range of detection for the CEA concentration using IMR extends well above the threshold of high risk level of colorectal carcinoma in current diagnosing practice. Therefore, IMR is also suitable in other stages diagnosis for colon cancer development.
Wheeled, Kinematically Redundant Locomotion System for Mobility-Oriented Research and Experimentation
Authors: Labenda Patrick , Neumann Marc , Sadek Tim
Published: June 2012

Mobile robots for inspection and surveillance of hard-to-reach and hazardous areas e.g. resulting from a building collapse in the course of a natural or man-made catastrophe have to possess enhanced rough terrain mobility capabilities. First, they must be able to navigate through a given environment and to avoid insurmountable obstacles. Second, they must have the ability to traverse different forms of ground without getting immobilized by a loss of traction. Third, they must be able to negotiate a wide spectrum of obstacles including e.g. wide gaps and high steps. These abilities can be described as a mobile robots performance indices “maneuverability”, “trafficability” and “terrainability”. As a consequence, mobile robot concepts for disaster control and search-and-rescue tasks always have to be developed and evaluated with regard to these performance indices. In principle, considerable potentials with regard to mobility in unstructured and rough environments offer kinematically redundant locomotion systems equipped with powered wheels or tracks which are inspired by their biological archetype snake. These potentials are based on the systems’ snake-like; modular design as well as their given kinematic redundancy. Due to their slender, modular and flexible design the systems are basically able to travel and maneuver through noticeable narrow passes and tunnels. Further on, their kinematic redundancy can be used for a purposeful posture and terrain adaptation to safeguard traction and the system’s trafficability, respectively. Finally, the systems’ modular and articulated design, both, can be used to achieve an outstanding terrainability and to be able to negotiate remarkable obstacles. The described and expected potentials of kinematically redundant locomotion systems have to be investigated in detail as well as evaluated in practice. To be able to do so, a demonstrator has been developed and implemented for intense mobility-oriented research and experimentation. The mobile robot and first experimental results are described in the paper at hand. The system stands out especially due to an innovative sensory for slip and contact force detection.
An Importance Sampling Approach for Time-Dependent Reliability
Authors: Singh Amandeep , Mourelatos Zissimos P. , Nikolaidis Efstratios
Published: June 2012

Reliability is an important engineering requirement for consistently delivering acceptable product performance through time. The reliability usually degrades with time increasing the lifecycle cost due to potential warranty costs, repairs and loss of market share. Reliability is the probability that the system will perform its intended function successfully for a specified time. In this article, we consider the first-passage reliability which accounts for the first time failure of non-repairable systems. Methods are available which provide an upper bound to the true reliability which may overestimate the true value considerably. The traditional Monte-Carlo simulation is accurate but computationally expensive. A computationally efficient importance sampling technique is presented to calculate the cumulative probability of failure for random dynamic systems excited by a stationary input random process. Time series modeling is used to characterize the input random process. A detailed example demonstrates the accuracy and efficiency of the proposed importance sampling method over the traditional Monte Carlo simulation.
Visual PID Control of a Redundant Planar Parallel Robot
Authors: Trujano M. A. , Garrido R. , Soria A.
Published: June 2012

This paper deals with the position regulation problem of a redundant planar parallel robot for the case in which only the joint position measurements are available, and presents an image based visual servoing scheme to solve this problem. It uses Proportional Integral and Derivative algorithm to compute the torques for the robot active joints together a linear filter to obtain velocity estimates from visual position measurements and shows that the robot end-effector converges to the desired position. Lyapunov Stability Theory allows concluding closed loop stability without invoking the LaSalle-Krassovsky invariance principle. Experimental results are presented for a laboratory prototype and allow evaluating the performance of the closed loop system.
Optimization of Face Cone Element for Spiral Bevel and Hypoid Gears
Authors: Fan Qi
Published: June 2012

In the blank design of spiral bevel and hypoid gears, the face cone is defined as an imaginary cone tangent to the tops of the teeth. Traditionally, the face cone element or generatrix is a straight line. On the other hand, the tooth root lines which are traced by the blade tips are normally not straight lines. As a result, the tooth top geometry generally does not fit the mating member’s real root shape, providing an uneven tooth root-tip clearance; additionally, in some cases root-tip interference between the tooth tip and the root tooth surfaces of the mating gear members may be observed. To address this issue, this paper describes a method of determining an optimized face cone element for spiral bevel and hypoid gears. The method is based on the incorporation of calculation of tooth surface and root geometries, the conjugate relationship of the mating gear members, the ease-off topography, and the tooth contact analysis. The resulting face cone element may not be a straight line but generally an optimized curve that, in addition to avoidance of the interference, offers maximized contact ratio and even tooth root-tip clearance. Manufacturing of bevel gear blanks with a curved face cone element can be implemented by using computer numerically controlled (CNC) machines.
Modelling Damping in Computer Simulations: Is All Damping Viscous?
Authors: Goyder Hugh
Published: June 2012

The standard damping model is the viscous dashpot for which the damping force is proportional to velocity. However, this simple model seems not to reflect real conditions where there may be viscoelastic effects, friction or air resistance. No general models for damping are available that can be developed from first principles and used in computer simulations. To help with this difficulty the fundamental theory that should underpin any general damping model is assembled here. The only available formulation for damping in mechanics is the Rayleigh dissipation model that can be used with Lagrange’s equation. This model is strictly viscous and linear. The possibility of using this model for all damping circumstances is examined. A starting point for the development of a theory is the need for causality. This need is used to formulate the concept of a pure dashpot (i.e. not mixed with other dynamic components) which is shown to be viscous. Furthermore in order to represent damping in general it is necessary to embed the viscous dashpot with other mechanical components which are not dissipative and are either linear or nonlinear. It appears that even for non-linear systems the only form of damper that is possible is the linear viscous dashpot.
Electrical Determination of Elastic Modulus of Individual PZT Nanofibers by In Situ SEM
Authors: Chen Xi , Shi Yong
Published: June 2012

We present an electrical measurement of elastic modulus of single electrospun lead zirconate titanate (PZT) nanofibers under harmonic vibration using in situ scanning electron microscopy (SEM) equipped with a nanomanipulator. The PZT nanofiber was fabricated using an electrospinning process and collected on a silicon substrate with 10 μm trenches. The individual PZT nanofibers were excited with an oscillating electric field applied by a network analyzer and the resonant frequency was observed through the SEM along with the transfer frequency spectra simultaneously. The elastic modulus was calculated as ∼70 GPa from this resonant frequency using Euler-Bernoulli equation.
A Variable-Size Local Domain Approach for Concurrent Design Optimization and Model Validation Using Parametric Bootstrap
Authors: Drignei Dorin , Mourelatos Zissimos P. , Kokkolaras Michael , Pandey Vijitashwa , Koscik Grzegorz
Published: June 2012

A common approach to the validation of simulation models focuses on validation throughout the entire design space. In a more recent methodology, we proposed to validate designs as they are generated during a simulation-based optimization process, relying on validating the simulation model through calibration in a sequence of local domains. In that work, the size of the local domains was held fixed and not linked to uncertainty, and the confidence in designs was quantified using Bayesian hypothesis testing. In this article, we present an improved methodology where the size and shape of the local domain at each stage of a sequential design optimization process, are determined from a parametric bootstrap methodology involving maximum likelihood estimators of unknown model parameters. Validation through calibration is carried out in the local domain at each stage. The sequential process continues until the local domain does not change from stage to stage during the design optimization process, ensuring convergence to an optimal design. The proposed methodology is illustrated with the design of a thermal insulator using one-dimensional, linear heat conduction in a solid slab with heat flux boundary conditions.
An Investigation on Centralized and Decentralized Supply Chain Scenarios at the Product Design Stage to Increase Performance
Authors: Chiu Ming-Chuan , Okudan Gu¨l E.
Published: June 2012

Design for supply chain has become an essential consideration while designing a new product. Previous studies have pointed out that early supplier involvement can contribute to the success of the product development and enhance the competitive advantage of the enterprise. However, most of the studies coordinating supplier selection and supply chain configuration make these decisions during the detail design stage, which is the last phase of product design. This research aims to investigate the supply chain scenarios for their relevant performance at the conceptual design stage. The performance of different supply chain scenarios, centralized and decentralized, are compared and discussed. The results show that the decentralized supply chain scenario is advantageous for the time performance of supply chain network whereas the centralized supply chain scenario demonstrates superiority on cost performance.
Whine Noise Development of Engine Timing Gear System in Heavy Duty Vehicle
Authors: Oh Sukil , Kang Koo-Tae , Soh Kang-Young , Kim Jung-Ho
Published: June 2012

Gear train is the most applied in the heavy duty engine timing system on the benefit of reliability, durability, timing accuracy, maintenance, and high torque transmission. But the gear train is vulnerable to rattle and whine noise due to many serial gear connections, which lead to more possibility for gear backlash impact and gear transmission errors compared with chain and toothed meshed belt timing systems. Furthermore, normal heavy duty diesel vehicles like truck and bus are well vibration isolated from engine at gear noise frequency range. Therefore, noise source control is inevitable in the developing process in heavy duty diesel vehicles. The objective of this paper is to reduce timing gear whine noise in the engine developing process for heavy duty vehicles. Main focus is modification of gear tooth shape in the proto engine developing process considering vehicle driving modes. To investigate engine timing gear whine noise, transmission error analysis was executed in accordance with proto type gears and optimal gear tooth modification was induced by transmission error analysis, engine bench, and vehicle test.
Atlas Database of 2-DOF Kinematic Chains and Its Application to the Creative Design of Mechanisms
Authors: Ding Huafeng , Kecskeme´thy Andre´s , Huang Zhen
Published: June 2012

Creation of novel kinematic structures of mechanisms has been a challenging issue which is usually conducted on experience and intuition. This paper, however, proposes a systematic method for the creative design of mechanism-based products and equipments on the basis of corresponding atlas database, and the creative design of an 11-link 2-DOF rode tractor is provided as an example. First, the transformation of the kinematic structure of mechanisms into graph representation is addressed. Then, the complete atlas database of 11-link 2-DOF kinematic chains is established by obtaining all the non-fractionated topological graphs through their contracted graphs and all the fractionated topological graphs through the combination of 1-DOF kinematic chains. Finally, based on the established atlas database, the creation design for the novel mechanisms of 11-link 2-DOF rode tractors is implemented, and all the nine novel feasible mechanisms (including the widely used one reported in literature) which satisfy the proposed performance indices are obtained.
Surface Modification of Polymer-Clay Nanocomposites by Excimer Laser Ablation
Authors: Chang I-Ta , Sancaktar Erol
Published: June 2012

This paper investigates the effects of nanoclay (Organically Modified Montmorillonite -OMMT) dispersion state and morphology of nanocomposites on laser induced surface micro/nano structure formation and modification of Polystyrene-Clay Nanocomposites at various OMMT concentrations. Injection molded sample surfaces were irradiated by a 248 nm KrF excimer laser in air. Scanning electron microscopy, atomic force microscopy and Fourier Transform Infrared (FTIR) spectroscopy with attenuated total reflectance accessory were utilized to analyze the ablated surface. Results show that, in general, better dispersion of OMMT leads to less continuous surface structures and more pronounced carbonyl regions on FTIR spectra. Clay nanoparticles are exposed on ablated surfaces and affect surface structure formation after irradiation by laser. A mechanism for the formation of excimer laser induced surface structures on injection molded parts is thus proposed.