The generation of bending sequences in a CAPP system for sheet-metal components

An important process-planning task in sheet-metal manufacturing is the determination of bending sequences for individual components. Computer-aided generation of these sequences, as part of a computer-aided process-planning (CAPP) system, can relieve the workload of process-planning departments, this being especially important in small batch manufacturing environments. This paper discusses the functions that have to be performed during the determination of bending sequences, focusing on accuracy aspects. The generation of bending sequences is also put into the broader perspective of an integrated CAPP system such as PART-S, which is under development presently in the author's laboratory

Large magnetoresistance using hybrid spin filter devices

A magnetic "spin filter" tunnel barrier, sandwiched between a non-magnetic metal and a magnetic metal, is used to create a new magnetoresistive tunnel device, somewhat analogous to an optical polarizer-analyzer configuration. The resistance of these trilayer structures depends on the relative magnetization orientation of the spin filter and the ferromagnetic electrode. The spin filtering in this configuration yields a previously unobserved magnetoresistance effect, exceeding 100%.Comment: 3.5 pages, 3 figures, submitted to Appl. Phys. Let

The local adsorption site of methylthiolate on Au(1 1 1): Bridge or atop?

Measurements of the local adsorption geometry of the S head-group atom in the Au(1 1 1)(√3 × √3)R30°–CH3S surface have been made using normal incidence X-ray standing waves (NIXSW) and S 1s scanned-energy mode photoelectron diffraction on the same surface preparations. The results confirm that the local adsorption site is atop an Au atom in a bulk-continuation site with a S–Au bondlength of 2.42 ± 0.02 Å, and that there can be no significant fraction of coadsorbed bridging species as recently proposed in a combined molecular dynamics/experimental study by Mazzarello et al. [R. Mazzarello, A. Cossaro, A. Verdini, R. Rousseau, L. Casalis, M.F. Danisman, L. Floreano, S. Scandolo, A. Morgante, G. Scoles, Phys. Rev. Lett. 98 (2007) 016102]. The results do not, however, clearly distinguish the different local reconstruction (adatom) models proposed for this surface

Pre-instructional strategies and segment length in interactive video programs

This study investigates the influence of pre-instructional strategies on the relationship between learner-controlled or program-controlled length of video segments and on related test performance on post-tests and retention tests. The study looks at the effect of presenting learning objectives in advance on the learning of factual information from interactive video programs. First-year students from two agricultural colleges in the Netherlands used a computer-controlled interactive video disk about the industrial process of cheese making and completed a posttest. A retention test was administered approximately two and a half weeks later. The program had two conditions, fixed and free. In the fixed condition, subjects worked through all seven chapters in linear order. In the free condition, students could vary the order of the chapters and view parts of the video as they wished. Results show a significant result for locus of control. Subjects in the no-pre-instruction condition performed better on test items that relate to incidental learning in the pre-instruction condition than on test items that relate to intentional learning in the pre-instruction condition. Overall, program control yielded a better posttest performance than learner control, although the effect size was rather small

Process planning for small batch manufacturing of sheet metal parts

The paper describes process planning for order-based small batch sheet metal part manufacturing. In this domain, general purpose CNC machinery and standard tools are being used. An example of a process planning system is given and some areas of special interest are discussed in more detail. Process planning for sheet bending and tolerance reasoning are important and intricate tasks within process planning, whereas abstractions in design and nesting are important due to their relations with other manufacturing functions. In general, manufacturing functions tend to become increasingly intertwined and traditional boundaries become blurred. Sheet metal industries, customers and suppliers alike, can benefit from this

Seismicity in the vicinity of Yucca Mountain, Nevada, for the period October 1, 2002 to September 30, 2003

Earthquake activity in the Yucca Mountain from October 1, 2002 through September 30, 2003 (FY03) is assessed and compared with previous activity in the region. FY03 is the first reporting year since the 1992 M 5.6 Little Skull Mountain earthquake with no earthquakes greater than M 3.0 within 65 km of Yucca Mountain. In addition, FY03 includes the fewest number of earthquakes greater than M 2.0 in any reporting year since the LSM event. With 3075 earthquakes in the catalog, FY03 represents the second largest number of earthquakes (second to FY02) since FY96 when digital seismic network operations began. The largest event during FY03 was M 2.78 in eastern NTS and there were only 8 earthquakes greater than M 2.0

Reply to Comment on 'Local methylthiolate adsorption geometry on Au(111) from photoemission core-level shifts'

A reply to the Comment by Albano Cossaro et al

Parameters affecting quality in manual assembly of engines

In manufacturing, it is vital that operators and other production personnel have the right information at the right time and right place. But what happens if we overestimate the usability of information for supporting the personnel in their assembly tasks?When does information serve as a quality assurance tool, and when does it become a too large part of the workload, thus reducing the time for core workplace activities, and instead becoming a part of the personnel’s workload? This paper reports on work that has been conducted at a heavy diesel engine assembly plant with the aim of finding information usability parameters that can affect the personnel negatively or positively. The paper presents and describes an evaluation of an existing information system at the plant. The aim of the evaluation was to find out why the assembly personnel, despite the fact that they had “all the information they needed”, did not always assemble the product according to specification and thereby caused an engine reject that had to be re-assembled. The initial hypothesis was that there would be a strong correlation between the production volume and the number of rejects due to “Information Overload”. However, the study revealed that the personnel do not use the IT system in a way that causes information overload. Instead, the degree to which the IT system supports/triggers different forms of information seeking behaviour is thought to be one of the main factors influencing internal reject