Allocating buffer storages in a pull system

This report proposes a method of estimating the amount of safety stock needed in each station of a production line due to variation in processing times, machine breakdowns and demand fluctuation in order to meet a predetermined desired level of performance. The production line is assumed to operate as a pull system and the measure of performance is the average percentage of demand backlogged. Multiple machines and different batch sizes in the stations are included in the model. Dynamic production control is used and is based on the current inventory level in every station of the system. Simulation results are used to test the performance of the system in which the maximum inventory level allowed in each station is based on the estimation given by our method.     

Elastohydrodynamic Film Thickness and Tractions for Oil-in-Water Emulsions

Emulsions, consisting of a small volume of oil dispersed in water in the form of small particles, are popular lubricants for metal rolling and some machine design applications. A number of mechanisms have been suggested for the lubricating behavior of emulsions, among which plate-out, starvation, and dynamic concentration are of particular interest here. At low speeds, the emulsion provides essentially the same lubricating ability as neat oil for a point contact, consistent with plate-out. At some critical speed, the emulsion behavior departs from the neat oil, associated with starvation of the inlet zone. At a second critical speed, dynamic concentration becomes the important mechanism. This article measures the film thickness and traction coefficients of oil-in-water emulsions in the different regimes of behavior and compares the results to existing theoretical understanding. The effect of droplet size is isolated as a causative element in fluid film formation.     

Tooling constraints and shop floor scheduling: evaluating the impact of sequence dependency

In a previous study, we began the process of examining how finite tooling resources affect the operation of a simulated job shop. The paper extends this line of research by focusing on the problem of how to schedule a shop operating with both finite machine and tooling resources, and faced by varying levels of tooling-related sequence dependency in the setups. Four tool assignment rules and two dispatching procedures are evaluated. Findings show the importance of using tool assignment rules which consider not only tool-related information such as tool availability but also the priority of the jobs waiting to be processed. Specifically, as the level of sequence dependence increases and the availability of tooling decreases, the performance of the shop is greatly influenced by the tool assignment rule used to manage the flow of tooling to and from work centres     

Effect of yeast strain selection on the concentration of cis- and trans-resveratrol and resveratrol glucoside isomers in wine

The influence of four fermentative yeast strains belonging to the Saccharomyces cerevisiae species, on the content of cis‐ and trans‐resveratrol and resveratrol glucoside isomers in Vitis vinifera L. cv. Shiraz grape musts during alcoholic fermentation was studied by reverse phase high performance liquid chromatographic (RP‐HPLC) analysis. During vinification an increase in both the free and the glucosidic forms was observed up to day three/five (cis‐ resveratrol/piceid) or day four (trans‐ isomers) after which varible yeast, β‐glucosidase activity was noted until dryness where a general increase in free forms of resveratrol was accompanied by a decrease in the corresponding glucoside. In the finished wines ready for bottling or aging, the total amount of all resveratrol forms reflected (P < 0.05) the manufacturers polyphenol extraction ratings for the strains. Relative extraction of total phenolics in red wine amongst different yeast strains was demonstrated to mimic relative stilbene content.     

PACKAGING PRESERVATION OF β-CAROTENE IN SWEET POTATO FLAKES USING FLEXIBLE FILM AND AN OXYGEN ABSORBER

Sweet potato flakes are potentially an affordable, shelf-stable source of provitamin A β-carotene. Because β-carotene is susceptible to oxidative degradation, particularly in dehydrated food materials exposed to atmospheric oxygen, several packaging conditions were evaluated for enhancement of β-carotene retention in sweet potato flakes during storage. The flakes were packaged in either a polypropylene film (high oxygen permeability) with air headspace or a nylon laminate film (low oxygen permeability) with air headspace, under vacuum, or with an Ageless oxygen absorber sachet enclosed. Packaged flakes were stored in the dark at ambient laboratory temperature (～23C), and β-carotene content was determined at intervals from 0 to 210 day storage using reversed-phase liquid chromatography. Among the packaging conditions tested, β-carotene retention was enhanced incrementally as the apparent availability of oxygen was reduced (nylon > polypropylene; oxygen absorber > vacuum > air headspace). The combined use of oxygen absorbers and flexible oxygen barrier film gave excellent retention of β-carotene during the 210 day trial.     

BRIDGING THE GAPS: HYBRID TRACKING FOR ADAPTIVE MOBILE AUGMENTED REALITY

Tracking accuracy in a location-aware mobile system can change dynamically as a function of the user's location and other variables specific to the tracking technologies used. This is especially problematic for mobile augmented reality systems, which ideally require extremely precise position tracking for the user's head, but which may not always be able to achieve that level of accuracy. While it is possible to ignore variable positional accuracy in an augmented reality user interface, this can make for a confusing system; for example, when accuracy is low, virtual objects that are nominally registered with real ones may be too far off to be of use.

To address this problem, we describe an experimental mobile augmented reality system that: (1) employs multiple position-tracking technologies, including ones that apply heuristics based on environmental knowledge; (2) coordinates these concurrently monitored tracking systems; and (3) automatically adapts the user interface to varying degrees of confidence in tracking accuracy. We share our experiences with managing these multiple tracking technologies, employing various techniques to facilitate smooth and reasonable “hand-offs” between the cooperating systems. We present these results in the context of an intelligent navigational guidance system that helps users to orient themselves in an unfamiliar environment, using path planning to guide them toward destinations they choose, and sometimes towards ones the system infers as equally relevant.     

中国国际建筑艺术实践展艺术和建筑博物馆

前言：中国空间中的平等透视 透视在中国和西方绘画中有着历史上的本质差别。13世纪后，西方绘画发展了定点透视中的灭点，中国的画家尽管对透视有意识，但拒绝使用一点透视法，而代之以乎平透视法。在平等透视法中，观察者穿行于画面中，转移的视点、空间的层次，弥漫的雾气和水面，这些特征塑造了中国绘画构图的深层次的神秘感。     

Industry Life Cycles

Evidence on entry, exit, firm survival, innovation and firmstructure in new industries is reviewed to assess whether industriesproceed through regular cycles as they age. A leading depictionof the evolution of new industries, the product life cycle,is used to organize the evidence. It is shown that the productlift cycle captures the way many industries evolve through theirformative eras, but regular patterns occur when industries aremature that are not predicted by the product life cycle. Regularitiesin entry, exit, firm survival and firm structure are also developedfor industries whose evolution departs significantly from theproduct life cycle. Opportunities for further research on thenature of industry life cycles and the factors that conditionwhich life cycle pattern an industry follows are discussed.     

Interconnection Pricing, Standed Costs, and the Optimal Regulatory Contract

Given the potential for strategic gaming inherent in networkproviders' reliance on their competitors for the supply of vitalinputs, interconnection pricing or the setting of prices USat which networks sell access to their facilities and theircustomers to other networks has become a critical issue in thedesign of policies to promote competition in telecommunicationdmarkets. Debate has focused on the prices entrants should payfor access to the facilities and customers on the incumbentlocal exchange carries (ILECs) who until recently were protectedmonopolies. A critical question is the size of the contributionscompetitors should make to incumbents' fixed costs and regulatoryburdens in the prices they pay for network elements and servicespurchased form ILECs.     

Globalization and the Undergraduate Manufacturing Engineering Curriculum

At an ASME panel on manufacturing engineering education, industry representatives emphasized preparation for globalization. The concept has not yet had widespread impact on undergraduate engineering curricula. In this paper the industry updates are summarized, especially as they pertain to undergraduate engineering education for a globalized economy, and synthesized with the literature on the subject. Objectives for manufacturing engineering education are derived and possible ways of introducing the subject into an undergraduate curriculum without lengthening the program are suggested. The findings should be applicable to manufacturing, mechanical, and industrial engineering.