Tribological investigations on micromachined silicon sliders

The continuous decrease in flying height and subsequent machining challenges spurred an interest in alternative slider materials, particularly single phase ones. Furthermore, due to a desire of the recording head industry to more closely follow semiconductor fabrication technologies, silicon has been taken into consideration as an interesting alternative to alumina-titanium carbide (Altic), used presently. In case silicon is to be introduced, extensive tribological investigations are required. This paper attempts to shed some light on some basic tribological properties of silicon sliders used on DLC coated metal disks by doing a pin-on-disk test at a low rotational velocity.     

Predicted effects of residential development on a northern Idaho landscape under alternative growth management and land protection policies

Land use change driven by exurban development can lead to dramatic alterations in the structure and function of landscapes. Residential development outside of urban and suburban zones can disrupt agricultural and forest management operations and ecosystem processes, increase community wildfire hazard, deplete groundwater resources, and lead to social conflict. We assessed two policy tools, urban growth boundaries and agricultural use zoning, for their potential to help manage growth and sustain the rural landscape. Using a survey-based model, we simulated the effects of the two policy tools on land use change and compared the results with predictions of land use change for two rural counties (4794 km²) in northern Idaho developed in a previous project. We measured the effects of predicted exurban development using four measures: number of housing units predicted on productive agricultural lands, number of housing units predicted on a groundwater resource area, changes to a wildfire hazard index for residential structures, and the social acceptability of residential development patterns given current development preferences. The two policy tools impose in substantially different landscape-level residential development patterns when compared to the baseline change prediction and each other. Each tool resulted in a variety of tradeoffs between negative and positive effects among our measures of impact. Our findings demonstrate the importance of using multiple indicators to evaluate growth management and land protection policy tools for making land use planning decisions.     

Work attitudes and decisions as a function of manager age and employee age.

Research has shown the importance of employee age relative to coworker age in determining attitudes, performance, and career-related opportunities. The authors used chronological and subjective measures of employee and manager age to determine whether employee age relative to the manager has an impact on these same outcome variables. One hundred eighty-five managers and 290 employees completed surveys. The strongest and most consistent age effects were observed for interactions between employee and manager chronological age. Both the magnitude and pattern of the employee-manager age interactions varied by self- and manager-rated outcome measures of work attitudes, performance and promotability assessments, and developmental experiences. Results are discussed in light of the relational demography and career timetable literatures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

COMMERCIAL BANK LENDING PRACTICES AND THE DEVELOPMENT OF BLACK OWNED CONSTRUCTION COMPANIES

ABSTRACT: Although the construction industry has been a tremendous growth industry for black entrepreneurs in recent years, black owned construction firms, on average, are less than half as large as those owned by nonminorities. Previous findings suggest that limited access to financial capital, particularly bank loans, has restricted the size of black owned businesses. Examination of nationwide random samples of construction companies reveals that black firms are treated differently by commercial banks than nonminority companies that have otherwise identical traits. Undercapitalization, in turn, is shown to increase the likelihood of firm discontinuance. Alleviation of undercapitalization problems would promote the development of black owned businesses in the construction industry.     

当今全球工业与公共设施清洁(I&I)领域的可持续性问题

<正>就在不久之前,可持续性还只是个人与家庭护理领域所关注的话题。而今天,我们已经意识到可持续性不仅仅局限于某个行业或地区。可持续性并非一种两者取其一的趋势;人们既不会接受性能方面的妥协,也不愿为可持续性支付昂贵的价格。II行业的解决方案主要基于三大要素:服务、设备和清洁化料。这三大要素在打造可持续解决方案方面都有着巨大的潜力。比如,服务人员的安全作业、节能设备以及基于可持续原材料的清洁化料等等。     

Submicron coatings for micro-tribological applications

The miniaturisation of mechanical components and machines enables innovative future products. However, for the improvement of functionality, reliability and lifetime of those micro systems, micro tribological coatings with thicknesses in the sub-micron range are needed. To cover these needs, we investigated different submicron coatings with the aim to develop wear and friction optimized thin films for this application. The basis of this work has been the state of the art know how of well established macroscopic coatings which in general are in a thickness range of a few micrometers. It turned out, that particularly the surface topography and the substrate material influence the properties of very thin films. For investigations with single asperity contact, the coefficient of friction (COF) was reduced by lowering the tip radius and the hardness of the substrate material. In contrast, for larger contact radii (pin-on-disc), an increase of the COF with decreasing substrate Youngs modulus was found. With respect to wear, it turned out that the wear depth increased dramatically with increasing initial surface roughness (R_a).The authors gratefully acknowledge the financial support of the German Research Foundation by grant SFB 516. We also thank T. Staedler and A. Wortmann for their contributions through their respective PhD Theses on this topic.     

Nanogrinding

Nanogrinding is an ultraprecision machining process well suited for surface machining of advanced ceramics. The machining kinematic is based on a lapping process, where the workpieces, forced by friction effects, revolve on a rotating plate. Lapping uses loose grain; however, for nanogrinding, the abrasive grain is completely embedded in a soft metallic plate, thus becoming the grinding tool. Therefore, nanogrinding is a two-step process. The first step is to create the grinding plate. In the second step, the workpiece is machined. Nanogrinding requires a significant grinding plate roughness, which is achieved by conditioning the plate with pumice. During this process, pumice is embedded in the grinding plate and remains there throughout the process. Between pumice particles, the basic soft metallic plate material forms plateus. Diamond grain is embedded here by a conditioning ring, with their summits aligned co-planar to the plate surface. This arrangement allows the performance of ductile machining, resulting in plastic material removal, minimal subsurface damage, and excellent surface finish.