Surface geometry of slide bearings after percussive burnishing

A review of literature about the effect of oil pockets on improvement of sliding elements tribological performance as well as about the changes of surface topography during “zero-wear” process is shown. The paper presents also the results of experimental investigations done in the Department of Manufacturing Processes and Production Organisation of Rzeszow University of Technology, connected with the creation of oil pockets on sliding surfaces. In order to simulate a deterministic surface a program for the visualisation of pits was written. The procedures for assessment of the oil pocket size of specific shape and oil pockets coverage are presented. The tendencies of changes of surface topography and oil pockets dimensions during “zero-wear” process are also described.     

Silicon models of lateral inhibition

The neurological process known as lateral inhibition (LI) has long been acknowledged as a critical operation for the preprocessing many types of sensory stimuli. In the mammalian retina, LI is utilized to enhance visual images by performing differential amplification on the pixels from which the image is composed. In this study, LI is implemented using VLSI-based models. These models consist of small two-dimensional arrays of generalized sensory pixels, each of which inhibits, and in turn is inhibited by, each of its immediate neighbors. Two custom CMOS array prototypes circuits have been designed, fabricated, and characterized. Test results indicate that both circuits are able to impart contrast to arbitrary two-dimensional geometric images in a flexible yet stable manner, and do so immediately and simultaneously. These arrays thus offer a level of performance not attainable by software methods, making this method well suited for machine vision systems that utilize parallel architectures.     

Psychophysical basis for maximum pushing and pulling forces: A review and recommendations

The objective of this paper was to perform a comprehensive review of psychophysically determined maximum acceptable pushing and pulling forces. Factors affecting pushing and pulling forces are identified and discussed. Recent studies show a significant decrease (compared to previous studies) in maximum acceptable forces for males but not for females when pushing and pulling on a treadmill. A comparison of pushing and pulling forces measured using a high inertia cart with those measured on a treadmill shows that the pushing and pulling forces using high inertia cart are higher for males but are about the same for females. It is concluded that the recommendations of Snook and Ciriello (1991) for pushing and pulling forces are still valid and provide reasonable recommendations for ergonomics practitioners. Regression equations as a function of handle height, frequency of exertion and pushing/pulling distance are provided to estimate maximum initial and sustained forces for pushing and pulling acceptable to 75% male and female workers.     

Empathy and Modern Technology: A Neuroergonomics Perspective

The primary purpose of this paper is to discuss the role of empathy in the design of advanced systems in manufacturing and service industries in order to ensure suitable working conditions for employees from the social and technological point of view. The origins and components of empathy are briefly reviewed. The neural underpinnings of three components of empathy, including cognitive, emotional, and behavioral aspects, are considered in the context of human–human and human–machine interactions, as well as design of working environments. Finally, the potential advantages of applying empathy‐related knowledge to the design and development of human‐centered technology are discussed.     

A general topology-based framework for adaptive insertion of cohesive elements in finite element meshes

Large-scale simulation of separation phenomena in solids such as fracture, branching, and fragmentation requires a scalable data structure representation of the evolving model. Modeling of such phenomena can be successfully accomplished by means of cohesive models of fracture, which are versatile and effective tools for computational analysis. A common approach to insert cohesive elements in finite element meshes consists of adding discrete special interfaces (cohesive elements) between bulk elements. The insertion of cohesive elements along bulk element interfaces for fragmentation simulation imposes changes in the topology of the mesh. This paper presents a unified topology-based framework for supporting adaptive fragmentation simulations, being able to handle two- and three-dimensional models, with finite elements of any order. We represent the finite element model using a compact and “complete” topological data structure, which is capable of retrieving all adjacency relationships needed for the simulation. Moreover, we introduce a new topology-based algorithm that systematically classifies fractured facets (i.e., facets along which fracture has occurred). The algorithm follows a set of procedures that consistently perform all the topological changes needed to update the model. The proposed topology-based framework is general and ensures that the model representation remains always valid during fragmentation, even when very complex crack patterns are involved. The framework correctness and efficiency are illustrated by arbitrary insertion of cohesive elements in various finite element meshes of self-similar geometries, including both two- and three-dimensional models. These computational tests clearly show linear scaling in time, which is a key feature of the present data-structure representation. The effectiveness of the proposed approach is also demonstrated by dynamic fracture analysis through finite element simulations of actual engineering problems.

A neuromime in VLSI

Using conventional very large scale integration (VLSI) technology, a flexible and comprehensive neuromime circuit has been implemented in silicon for the purpose of modeling nerve networks from living organisms. Based on the "integrate-and-fire" model of neuronal threshold, the circuit was fabricated in two-micron CMOS with double-level metal. It occupies 0.6 square millimeters of die area, and requires only a few passive biasing components off-chip. The neuromime circuit offers many continuously variable parameters, including excitatory and inhibitory sensitivity and persistence, refractory duration and strength, and overall speed of operation. The circuit offers free and continuous access to waveforms for presynaptic membrane potential, postsynaptic membrane potential, and threshold potential. As such, it is amenable to many secondary behavioral characteristics, such as postinhibitory rebound, fatigue, facilitation, and accommodation. Being power-efficient, compact, and noise immune, it is ideal for assembly into networks and interfacing to biological counterparts.     

Fast and versatile texture-based wireframe rendering

This paper revisits the problem of wireframe rendering, which, at first, appears to be an easily solved problem. However, the conventional solution is inefficient and does not result in high-quality images. Recently, graphics hardware programming has been employed to achieve high-quality solid line rendering. In this paper, we present a simpler and faster technique for wireframe rendering based on texture mapping. Our technique does not require (but can benefit from) graphics hardware programming and thus can be easily integrated into existing rendering engines, while resulting in fast, accurate, high-quality, anti-aliased, and still versatile, wireframe drawing. For topologically structured meshes, our approach allows the rendering of wireframe decoupled from the underlying mesh, making possible the rendering of original wireframes on top of decimated meshes.     

A roadmap for a methodology to assess,improve and sustain intra‐ and inter‐enterprise system performance with respect to technology‐product life cycle in small and medium manufacturers

Increased manufacturing costs are forcing U.S. manufacturing firms to send their operations off shore. Such business practices are greatly impacting the vitality of small and medium manufacturers (SMMs) in the U.S. economy. This article intends to advance the notion of the need for a methodology for assessment, improvement, and sustainability of intra‐ and inter‐enterprise system performance along the technology–product development life cycle. The aims of this article are to: (1) provide an overview of the technology–product development process; (2) document the different states of manufacturing technology readiness levels; (3) present an overview of prior methodologies reported on the subject in the published literature; and (4) establish a road map for assessment, improvement, and sustainability of intra‐ and inter‐enterprise system performance along the path of the technology–product development life cycle. A notion is advanced about the readiness of SMMs with respect to assessment, improvement, and sustainability of intra‐ and inter‐enterprise system performance. A road map is outlined for the deployment of a methodology to address the issues across the supply chain. © 2007 Wiley Periodicals, Inc.     

Applications of fuzzy‐based linguistic patterns for the assessment of computer screen design quality

The main objective of this study was to develop a modeling framework which would unify different aspects of computer screen design and result in a quantitative criterion for an optimized computer screen format. The fuzzy set‐based linguistic design patterns were utilized as a tool to build this model. The linguistic patterns are based on categories of expressions related closely to natural language and truth values, which are close to a human designer's intuition. The proposed framework is capable of assessing the quality of computer screen design based on existing knowledge in human‐computer interface domain using the fuzzy‐based linguistic pattern approach. Exemplary patterns for an optimal screen density, information grouping, and some aspects of screen layout are presented, along with a sequence of calculations based on the exemplary screen format. This study showed that it is possible to achieve a rational and relatively easy to interpret assessment of different screen designs in the form of the degrees of truth. Such an evaluation criterion reflects the compatibility of a given screen design with the optimal one based on the current knowledge in the field. It is believed that the proposed methodological framework for computer screen design should significantly augment the efforts of human designers.