Many supply chains strive to shorten the time between a customer’s order and the actual delivery of the ordered goods. Cross docking is one of the options to reduce these response times. Cross docking facilities are dynamic environments where products arrive and leave the same day. To deal with these dynamic aspects, the need for efficient control policies in combination with flexible and easy to reconfigure storage area layouts increases. We present a dynamic design methodology to select control policies and determine layout rules for cross docking facilities. We present both advantages and disadvantages of the proposed layout procedures. We use the cross docking center of the “Royal Horticultural Company Lemkes” in The Netherlands as the basis for a comparative analysis of the procedures presented. We show that, by applying our design methodology, a savings of 16% can be obtained in total travel distances of employees. 相似文献
The generation of microcellular foams via a photochemical initiation mechanism is a new approach aimed at the one step production of three dimensional structures in offset printing techniques. The photochemical foaming involves the excitation of a selected photoacid generator with ultra-violet (UV) light to release Brønsted acids. Carbon dioxide, formed upon the reaction of the Brønsted acid with calcium carbonate particles, is used as blowing agent. In order to achieve efficient proton formation and consequently generate a sufficient amount of blowing agent, photosensitizers are employed. Long wavelength absorbing anthracene derivates are added to capture a higher fraction of the light source, a conventional mercury arc lamp, to sensitize the photolysis of the photoacid generator. The microcellular foaming was performed with a commercially available UV curable offset ink formulation containing triacrylate oligomers. To ensure that the gas bubbles are trapped in the cured resin a balance has to be found between the curing speed of the ink and the foaming speed. In the present study crucial process parameters including photoacid generator level, choice of photosensitizer, light intensity and concentration of calcium carbonate particles are evaluated and their influence on the foam properties are discussed. Both the cell morphology and the expansion of the film thickness are characterized with optical microscopy and mechanical methods. The results clearly show that the UV assisted foaming leads to the formation of dense and uniform microcells by applying optimized process parameters. Moreover, the relative thickness of the ink layer can be raised up to 90% which makes the one-step production of three dimensional structures (e.g. reliefs) at short reaction times and ambient temperatures feasible. 相似文献
Floods are often preceded by warnings such as heavy rain that may make preparatory activities possible in order to prevent flooding from actually happening. However, flood emergency preparedness lacks insight in logistical aspects. This paper develops a framework of logistical aspects of emergency measures that support preventing catastrophic breaching of flood defences during extreme situations. The Netherlands is taken as a reference because large parts of the country are prone to flooding. Furthermore, the Netherlands has a long‐standing experience with implementing flood emergency measures. This paper is particularly focused on the role of Water Boards, the Dutch government agencies responsible for securing flood defences. Structured interviews with Water Boards are used to develop and illustrate a framework of logistical aspects for emergency flood preparedness. 相似文献
It is now clear that positive emotion leads to enhanced psychological functioning. What is less clear, however, is just why this is so. Drawing on a social-functional perspective, we argue that positive emotional behavior that accurately signals to others the individual's internal state will enhance social connectedness. Positive emotional behavior that does not accurately signal a person's experience—such as a smile that is not felt—may impede social connectedness and, in turn, psychological functioning. This perspective suggests that (a) the degree to which experience and behavior are dissociated during positive emotional episodes, over and above level of positive behavior, should predict worse psychological functioning and (b) the effect of dissociation should be mediated by social connectedness. To test these hypotheses, we conducted a short-term prospective longitudinal study, with a baseline assessment of depressive symptoms and well-being at Time 1. Six months later, at Time 2, we used a novel within-individual laboratory paradigm to measure the degree to which positive emotional behavior was dissociated from (vs. coherent with) a participant's positive emotional experience. We also assessed level of positive behavior and experience. Then, another 6 months later, we assessed social connectedness as a mediator and depressive symptoms and well-being as outcomes at Time 3. Even when controlling for baseline functioning and for level of positive emotion behavior and experience, we found that greater positive experience–behavior dissociation at Time 2 predicted higher levels of depressive symptoms and lower levels of well-being at Time 3. As predicted, these associations were mediated by social connectedness. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
A void exists in development of design theory methodology within the structural engineering community. This void hampers efforts to resolve performance deficiencies including cost over-runs, unplanned rework, and suboptimal design. In manufacturing, product design and production improvements have resulted from implementation of the design structure matrix (DSM) methodology. DSM offers a means to represent, analyze, and decompose complex systems in order to improve their performance. DSM use within the architecture engineering construction (AEC) industry has been sporadic and focused primarily in the U.K. Where applied, DSM has proven effective at helping AEC design teams streamline processes to address nonlinearity (nonsequential information flows) introduced by iteration and complexity in design. When a DSM reveals iteration and highly dependent work, group brainstorming, collocated design sessions, rapid feedback, set-based design, and collaborative design aids can be used to increase overall team effectiveness. This paper examines a case study where DSM-based planning software was used on a seismic retrofit project to drive process improvement in design management. DSM correctly identified iterative activities central to design and provided the following; (1) a common vocabulary to discuss rework in the context of a multidisciplinary design team; (2) a rational method to schedule team collocation and brainstorming efforts to maximize their benefit; and (3) a means to consider iterative activities (and associated hand-offs) in design work structuring. 相似文献
Bivalent modulators of P‐glycoprotein : A small library of flavonoid homodimers and heterodimers was synthesized, and their in vitro activity in reversing paclitaxel resistance was evaluated along with structure–activity relationships. SAR trends indicate that flavonoid dimers with nonpolar, hydrophobic, less bulky substituents generally show more potent reversing activity. This will help guide future efforts in the search for more potent compounds.
A series of short chain fatty acid derivatives of aminimides were shown to possess hypolipidemic activity in rats and mice.
Most of the agents tested lowered both serum cholesterol and triglyceride levels by at least 30% in mice and were effective
in hyperlipidemic induced mice. 1,1-Dimethyl-1-(2-hydroxypropyl)-amine mersitimide lowered serum cholesterol levels 41% and
serum triglyceride levels 56% at 20 mg/kg/day I.P. after 16 days. The same agent was active orally when administered to rats
with a 38% reduction in serum cholesterol and a 52% reduction in serum triglycerides after 14 days. The agents inhibited liver
acetyl CoA synthetase, ATP dependent citrate lyase and phosphatidate phosphohydrolase activities in vitro and in vivo. Reduction
of cholesterol, triglycerides, neutral lipids and phospholipid levels were noted in the livers of mice treated for 16 days.
In rat studies, cholesterol, triglyceride and phospholipid levels were reduced in liver, small intestine and the feces after
two weeks' dosing. The cholesterol content was reduced in the very low density lipoprotein (VLDL) and low density lipoprotein
(LDL) fractions but elevated in the high density lipoproteins (HDL). Triglyceride levels were lowered in the VLDL, and neutral
lipid levels were reduced in the chylomicron and VLDL fractions. 相似文献
Examines the development, since 1950, of group psychotherapy with the elderly. The strengths and weaknesses of the research generated during this period are highlighted, with particular attention to the critical elements of group psychotherapy that make it effective for use with both institutionalized and community-dwelling elderly. (74 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献