Investigations into vocal doses and parameters pertaining to primary school teachers in classrooms

Investigations into vocal doses and parameters were carried out on 40 primary school teachers (36 females and 4 males) in six schools in Italy, divided into two groups of three, A and B, on the basis of the type of building and the mid-frequency reverberation time in the classrooms, which was 1.13 s and 0.79 s, respectively. A total of 73 working-day samples were collected (66 for females and 7 for males), from which 54 traditional lessons were analyzed separately. The average value over the working days of the mean sound pressure level of the voiced speech at 1 m from the teacher's mouth was 62.1 dB for the females and 57.7 dB for the males, while the voicing time percentage was 25.9% and 25.1%, respectively. Even though the vocal doses and parameters did not differ for the two school groups, the differences in the subjective scores were significant, with enhanced scores in group B. A 0.72 dB increase in speech level per 1 dB increase in background noise level, LA90, was found during traditional lessons, as well as an increase in the mean value of the fundamental frequency with an increase in LA90, at a rate of 1.0 Hz/dB

Time Value of Commercial Product Returns

Manufacturers and their distributors must cope with an increased flow of returned products from their customers. The value of commercial product returns, which we define as products returned for any reason within 90 days of sale, now exceeds US $100 billion annually in the US. Although the reverse supply chain of returned products represents a sizeable flow of potentially recoverable assets, only a relatively small fraction of the value is currently extracted by manufacturers; a large proportion of the product value erodes away due to long processing delays. Thus, there are significant opportunities to build competitive advantage from making the appropriate reverse supply chain design choices. In this paper, we present a simple queuing network model that includes the marginal value of time to identify the drivers of reverse supply chain design. We illustrate our approach with specific examples from two companies in different industries and then examine how industry clockspeed generally affects the choice between an efficient and a responsive returns network

Supply Chain Coordination for False Failure Returns (ed.2)

False failure returns are products that are returned by consumers to retailers with no functional cosmetic defect. The cost of a false failure return includes the processing actions of testing, refurbishing if necessary, repackaging, the loss in value during the time the product spends in reverse supply chain (a time that can exceed several months for many firms), and the loss in revenue because the product is sold at a discounted price. This cost is significant, and is incurred primarily by the manufacturer. Reducing false failure returns, however, requires effort primarily by the retailer, for example informing consumers about the exact product that best fits their needs. We address the problem of reducing false failure returns via supply chain coordination methods. Specifically, we propose a target rebate contract that pays the retailer a specific dollar amount per each unit of false failure returns below a target. This target rebate provides an incentive to the retailer to increase her effort, thus decreasing the number of false failures and (potentially) increasing net sales. We show that this contract is Pareto–improving in the majority of cases. Our results also indicate that the profit improvement to both parties, and the supply chain, is substantial

A comparison of repaired, remanufactured and new compressors used in Western Australian small- and medium-sized enterprises in terms of global warming

Repaired compressors are compared with remanufactured and new compressors in terms of economic andenvironmental benefits. A detailed life cycle assessment has been carried out for compressors under threemanufacturing strategies: repaired, remanufactured and new equipment. The life cycle assessment of the globalwarming potential of repaired compressors varies from 4.38 to 119 kg carbon dioxide equivalent (CO2-e),depending on the type of components replaced. While greenhouse gas emissions from the remanufacturedcompressors (110 to 168 kg CO2-e) are relatively higher than those from the repaired ones (4.4 to 119 kg CO2-e), anew compressor has been found to produce a larger amount of greenhouse gas emissions (1,590 kg CO2-e)compared to both repaired and remanufactured compressors. Repairing failed compressors has been found to offerend users both dollar and carbon savings in contrast to remanufactured and new compressors. The research alsofound that extended lifetime is more important than the manufacturing processes in terms of greenhouse gasemissions. Since a remanufactured compressor offers a longer life than a repaired compressor, the replacement ofthe latter with the former can avoid 33% to 66% of the greenhouse gas emissions associated with a newcompressor production with a lifetime of 15 to 25 years

Coordination in closed-loop supply chain with price-dependent returns

This paper proposes two Closed-loop Supply Chain (CLSC) games in which a manufacturer sets some green activity programs efforts and a retailer sets the selling price. Both strategies influence the return rate, which is a state variable. The pricing strategy plays a key role in the identification of the best contract to achieve coordination as well as in achieving environmental objectives. The pricing strategy influences the return rate negatively, as consumers delay the return of their goods when the purchasing (and repurchasing) price is high. We then compare a wholesale price contract (WPC) and a revenue sharing contract (RSC) mechanism as both have interesting pricing policy implications. Our result shows that firms coordinate the CLSC through a (WPC) when the sharing parameter is too low while the negative effect of pricing on returns is too severe. In that case, the low sharing parameter deters the manufacturer to accept any sharing agreements. Further, firms coordinate the CLSC when the sharing parameter is medium independent of the negative impact of pricing on returns. When the sharing parameter is too high the retailer never opts for an RSC. We find that the magnitude of pricing effect on returns determines the contract to be adopted: For certain sharing parameter, firms prefer an RSC when the price effect on return is low and a WPC when this effect is high. In all other cases, firms do not have a consensus on the contract to be adopted and coordination is then not achieved

Ablative Z-Pinch Pulsed Plasma Thruster

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77148/1/AIAA-4362-652.pd

A decomposition algorithm for robust lot sizing problem with remanufacturing option

In this paper, we propose a decomposition procedure for constructing robust optimal production plans for reverse inventory systems. Our method is motivated by the need of overcoming the excessive computational time requirements, as well as the inaccuracies caused by imprecise representations of problem parameters. The method is based on a min-max formulation that avoids the excessive conservatism of the dualization technique employed by Wei et al. (2011). We perform a computational study using our decomposition framework on several classes of computer generated test instances and we report our experience. Bienstock and Özbay (2008) computed optimal base stock levels for the traditional lot sizing problem when the production cost is linear and we extend this work here by considering return inventories and setup costs for production. We use the approach of Bertsimas and Sim (2004) to model the uncertainties in the input