Evaluation of the impact of information delays on flexible manufacturing systems performance in dynamic scheduling environments

The significance of the adverse effects of information delays (IDs) on flexible manufacturing system (FMS) performance is getting increasing attention from manufacturing systems managers, planners, schedulers, Enterprise Resource Planning software developers, and researchers because of their potential to disrupt production schedules. In this paper, we examine the extent of the adverse impact that IDs have on FMS performance. The FMSs are assumed to operate in a “review period” mode; i.e., the control decisions (e.g., sequencing and dispatching) are taken based on information monitored at predetermined intervals of time called “review periods”. The performance deterioration occurs due to the obsolescence of system status information. Key empirical findings based on extensive simulation experiments are: (1) IDs significantly degrade FMS performance for due date-based measures (mean tardiness and percent of jobs tardy); (2) IDs also degrade FMS performance for non-due date-based measures (mean flowtime and average machine utilization), albeit to a less severe degree; (3) routing flexibility, often regarded as a significant factor to influence FMS performance, is superseded by status review information delay.     

Do horizontal relationships matter to production and operations managers?

This paper shifts the focus of production, operations and supply chain management business relationships from the vertical to the horizontal side and calls for more research on this issue. The main intent is to provide managerially oriented arguments regarding the linkages between the achievement of operations-related goals and decisions related to horizontal business relationships. Specifically, we address the following research question: Does a linkage exist between production and operations objectives and the decisions a company makes about horizontal agreements, particularly horizontal governance mode choice? To answer this research question, we develop literature-based hypotheses and collect data from 4316 agreements of mergers and acquisitions and alliances and joint venture announced and completed between 2000 and 2010 by 88 of the first 100-ranked members of the Fortune 500 in the year 2000. We then test the hypotheses through a binary logistic regression model. This study brings interesting results and findings in terms of how and why production management considerations should play a crucial role in the type of strategic decisions that are usually reserved for finance and strategy managers. Operations managers should be fully involved in such decisions if they are to be well acquainted about how their choices impact on operational objectives.     

A Stiff Injectable Biodegradable Elastomer

Injectable materials often have shortcomings in mechanical and drug‐eluting properties that are attributable to their high water contents. A water‐free, liquid four‐armed PEG modified with dopamine end groups is described which changes from liquid to elastic solid by reaction with a small volume of Fe³⁺ solution. The elastic modulus and degradation times increase with increasing Fe³⁺ concentrations. Both the free base and the water‐soluble form of lidocaine can be dissolved in the PEG₄‐dopamine and released in a sustained manner from the cross‐linked matrix. PEG₄‐dopamine is retained in the subcutaneous space in vivo for up to 3 weeks with minimal inflammation. This material's tailorable mechanical properties, biocompatibility, ability to incorporate hydrophilic and hydrophobic drugs and release them slowly are desirable traits for drug delivery and other biomedical applications.     

Relaxations in Ba2BiTaO6 ceramics investigated by impedance and electric modulus spectroscopies

Impedance spectroscopy analysis of the dielectric properties of a Ba₂BiTaO₆ ceramic was performed in the temperature range from room temperature to 500 K. The sample was prepared using conventional solid state synthesis under air and the X-ray diffraction shows the presence of Ba₅Ta₄O₁₅ as a minor secondary phase (0.09%). The impedance data clearly show contributions of the grain and grain boundary. The results indicate that the conduction in Ba₂BiTaO₆ is due to hopping of oxygen vacancies and that the impurities not influence the conduction mechanism.     

Deal or no deal: Can incentives encourage widespread adoption of intelligent speed adaptation devices?

Given the burden of injury, economic, environmental and social consequences associated with speeding, reducing road traffic speed remains a major priority. Intelligent speed adaptation (ISA) is a promising but controversial new in-vehicle system that provides drivers with support on the speed-control task. In order to model potential system uptake, this paper explores drivers’ preferences for two different types of ISA given a number of alternative fiscal incentives and non-fiscal measures, using a stated preference approach. As would be expected with such a contentious issue, the analysis revealed the presence of significant variations in sensitivities and preferences in the sample. While a non-negligible part of the sample population has such strong opposition to ISA that no reasonable discounts or incentives would lead to them buying or accepting such a system, there is also a large part of the population that, if given the right incentives, would be willing or even keen to equip their vehicle with an ISA device.     

Evaluating Three Criteria for Establishing Cue-Search Hierarchies in Inferential Judgment.

The authors identify and provide an integration of 3 criteria for establishing cue-search hierarchies in inferential judgment. Cues can be ranked by information value according to expected information gain (Bayesian criterion), cue-outcome correlation (correlational criterion), or ecological validity (accuracy criterion). All criteria significantly predicted information acquisition behavior; however, in 3 experiments, the most successful predictor was the correlational criterion (followed by the Bayesian). Although participants showed sensitivity to task constraints, searching for less information when it was more expensive (Experiment 1) and when under time constraints (Experiment 2), concomitant changes in the relative frequency of acquisition of cues with different information values were not observed. A rational analysis illustrates why such changes in the frequency of acquisition would be beneficial, and reasons for the failure to observe such behavior are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

In Situ Oxidation by Fracture Emplaced Reactive Solids

In low permeability but naturally fractured media, vertical leaching or volatilization of toxic organic compounds can lead to high exposures and unacceptable human health or environmental risk. A field test was recently completed to evaluate in situ remediation at such sites by using hydraulic fracturing to emplace iron metal (Fe0) and permanganate (KMnO4) solids in the subsurface to chemically treat trichloroethylene (TCE). At an old land treatment site, two test cells were installed in silty clay soils with hydraulic fractures filled with either iron metal or permanganate solids at 1.8, 2.4, and 3.6 m depths. Fracture emplacement was monitored, and soil and ground water conditions were characterized. After 3, 10, and 15 mo of emplacement, continuous cores were collected and morphologic and geochemical data were taken across the fracture zones. Controlled degradation tests were completed using site ground water with TCE concentrations near 53, 144, and 480 mg∕L, equivalent to 0.5, 1.2, and 4.1 g TCE per kg media, respectively. The iron-filled fractures formed a discrete reactive seam less than 1 cm thick, wherein the Eh decreased and reductive dechlorination could occur, but effects in the adjacent silty clay soils were negligible. Though the emplaced iron exhibited some surface corrosion after extended emplacement in the subsurface, its reactivity was unaffected. Iron from the fractures degraded TCE at efficiencies of as much as 36% after 24–48 hr of contact, which is consistent with Fe0 packed bed degradation half-lives of 1 to 2 hr. The permanganate-filled fractures yielded a diffuse reactive zone that expanded over time, reaching 40 cm in thickness after 10 mo. Throughout this oxidizing zone, the degradation efficiency was >99% after 2 hr of contact for dissolved TCE at 0.5 and 1.2 mg TCE per g of media. When exposed to higher TCE loadings (i.e., 4.1 mg per g), degradation efficiencies after 10 mo dropped to 70% as the TCE load exceeded the oxidant capacity remaining. These efficiencies and rates are consistent with oxidation stoichiometry and previously determined half-lives of <2 min for permanganate oxidation of TCE. In both test cells there were no marked effects on the chemistry or contamination levels in the ground water beneath the cells. Though the results of this research are promising for emplacement of horizontal treatment zones, further work is required to support full-scale application.     

Design and Fabrication of Absorber Coupled TES Microbolometers on Continuous Silicon-Nitride Windows

The implementation of TES based microbolometer arrays will achieve unprecedented sensitivities for mm and sub-mm astronomy through fabrication of large format arrays and improved linearity and stability arising from strong electro-thermal feedback. We report on progress in developing TES microbolometers using Mo/Au thin films and Au absorbing structures. We present measurements of suppressing the thermal conductance through the etching of features on a continuous Silicon-Nitride window.      

Analysis Versus Production: Adolescent Cognitive and Attitudinal Responses to Antismoking Interventions

This study examined cognitive and attitudinal responses of adolescents to two inoculation-based media-literacy intervention approaches designed to reinforce adolescents' attitudes against smoking. Participants were junior high students (sixth, seventh, and eighth grade) from schools in the northeast. Two kinds of experimental workshops and a control group were used in a repeated measure nonequivalent group experimental design. The two intervention workshops developed included analysis (where participants discussed and analyzed cigarette and antismoking ads) and production (where participants discussed, analyzed, and then created their own antismoking ads). Results showed an overall support for the production workshop in eliciting more attention and positive workshop perceptions than the analysis workshop. The production workshop was also successful in reducing positive attitudes toward smoking over time. Implications and directions for future research are discussed including implications for theories of message processing.     

South East Europe's electricity sector: Attractions,obstacles and challenges of Europeanisation

The Energy Community is a bold experiment in integration, creating a regional energy market between the European Union and nine South East European partners – Albania, Bosnia-Herzegovina, Bulgaria, Croatia, Montenegro, the Former Yugoslav Republic of Macedonia, Romania, Serbia and the United Nations Mission on behalf of Kosovo. This paper examines the challenges posed by the application of the EU model of energy regulation and the acquis communautaire, and the ability of States to meet those challenges.An investigation of governance in the countries of South East Europe (SEE), including analysis based on the World Bank's Worldwide Governance Indicators, suggests a lower overall performance of governing institutions in SEE, compared with countries of the EU 25. The paper, therefore, considers whether the EU energy model is appropriate in South East Europe at this stage. The EU model confers certain institutional resources, but at the same time imposes significant costs of compliance with the energy chapter of the acquis. It remains to be seen which of these two opposing factors will dominate, but the analysis suggests that for some countries in the region, regulatory reform alone may not be sufficient.