Preemption in single machine earliness/tardiness scheduling

We consider a single machine earliness/tardiness scheduling problem with general weights, ready times and due dates. Our solution approach is based on a time-indexed preemptive relaxation of the problem. For the objective function of this relaxation, we characterize cost coefficients that are the best among those with a piecewise linear structure with two segments. From the solution to the relaxation with these best objective function coefficients, we generate feasible solutions for the original non-preemptive problem. We report extensive computational results demonstrating the speed and effectiveness of this approach.     

Assessing the electricity energy efficiency of university campus exterior lighting system and proposing energy-saving strategies for carbon emission reduction

Microsystem Technologies - This paper presents efficiencies research and energy-saving strategies for carbon emission reduction of the exterior lighting system of Avşar Campus of...     

RECENT ADVANCES IN BIOHASS TECHNOLOGY

Abstract

The concept that blomass represents a source of liquid fuel and of different raw materials has led to the development of various research programmes In this field. Our Investigations in this direction are based on the following premises: (1) all kinds of blomass incorporate almost the same components, (2) energy from conventional forestry (forest energy) and from energy plantations (energy forestry), (3) energy from wood powder as an upgraded wood fuel, (4) the macromolecular compounds existing in the blomass Incorporate biosynthesis energy, and their conversion to useful products, (5) oils by liquefaction of blomass with different catalytic and noncatalytic processes, and (6) by conversion of blomass to solid, liquid, and gaseous fuels by pyrolysis and gasification.     

Extrusion of poly(ether imide) foams using pressurized CO2: Effects of imposition of supercritical conditions and nanosilica modifiers

Foams of an engineering plastic, poly(ether imide), were extruded using a single screw extruder employing pressurized CO₂ as the blowing agent. The porosity, pore size distributions, and the density of the foams were especially affected by the pressure drop, the pressure loss rate, and temperature at the die. Significant increases in porosity and pore size and corresponding decreases in density were observed when the pressure imposed on CO₂ became greater than the critical pressure values of CO₂ (i.e., the temperature was always greater than the critical temperature of the CO₂ in the extruder and the die). The viscoelastic material functions of the extruded foams depended especially on the density of the foam, with the elastic modulus increasing with density. The incorporation of nanosilica particles in the 0.08–0.6% by weight range increased only the density of the foam and did not provide any benefits in controlling of the nucleation rate and the pore size distribution, presumably due to their poor dispersibility and agglomerated state in the single screw extruder. POLYM. ENG. SCI., 54:2064–2074, 2014. © 2013 Society of Plastics Engineers     

Interplay between Buy-It-Now price and last minute bidding on online bidding strategies

Sellers and buyers on online auction sites like eBay have the option of setting and executing auction parameters such as auction length, Buy-It-Now price, starting price, reserve price, etc. Understanding why bidders choose to execute the Buy-It-Now price as opposed to submitting a bid at the last minute of an auction helps managers better choose auction parameters and generate more revenue. In this paper, we first study online bidder behavior pertaining to the execution of the Buy-It-Now option as opposed to the last minute bidding strategy on eBay. Consequently, we study the seller’s decision to set a Buy-It-Now option and the amount of it. Our main finding is that a dominant strategy for the seller is to offer a Buy-It-Now option at the beginning of the auction. An early bidder arriving at the auction site is indifferent in choosing threshold Buy-It-Now prices or moving onto the auction and under particular circumstances strategically waiting for the last minutes of the auction to submit a bid. We also provide conditions on the existence of a set of equilibria which predicts the outcome of the game of executing the Buy-It-Now option versus last-minute bidding on eBay.