Glycerol Ethers Production and Engine Performance with Diesel/Ethers Blend

Spherical silica supported Hyflon^® catalysts (SSHC) were developed to produce ethers from glycerol by etherification reaction with isobutene. SSHC allowed to obtain yields to di- and tri-ethers, suitable as additives or components for diesel fuels, higher than that obtained with A-15 commercial catalyst, and a concentration of undesired mono-ether (not soluble in diesel) lower than 3 wt%. The novel catalysts investigated were found stable and easily reusable; their low acid site density prevented the occurrence of oligomerization reaction accounting for di-isobutene formation. Engine tests performed using a blend containing 10 vol% of glycerol ethers mixture confirmed the positive role of additives in reducing emissions of particulates and unburned hydrocarbons with significant improvement of diesel combustion efficiency.     

An optimal decision-making approach for the management of radiotherapy patients

In this paper, novel integer programming formulations are developed for solving the optimal scheduling of patients waiting for radiotherapy treatment. In this specific clinical domain, the suitable management and control of a patients’ waiting list strongly affect both the quality of the therapeutical outcome, in terms of effectiveness, and the cost-saving use of the overall therapeutical resources, in terms of efficiency. The proposed models allow the best scheduling strategy to be devised by taking into account the quality of the health care service offered to the patient as well as the status and the preferences of the patient. The computational experiments, carried out on realistic scenarios and considering real data, are very promising and show the efficiency and robustness of the proposed models to address the problem under consideration.     

High Frequency Ultrasonic Investigation for Ceramic Materials to Test the Manufacturing Process

Abstract

High frequency ultrasonic techniques for nondestructive tests of fine grained ceramic materials are presented. Green and partially sintered are considered. To this purpose, ultrasonic velocities and attenuation were measured and correlated to the porosity degree reached in different phases of the manufacturing process. A physical understanding of the experimental results is achieved by comparing them with the theoretical predictions provided by a self consistent scattering theory introduced in the 1980s. Finally, porosity maps are proposed since they give a comprehensive view of the process quality.     

Push &; Pull: autonomous deployment of mobile sensors for a complete coverage

Mobile sensor networks are important for several strategic applications devoted to monitoring critical areas. In such hostile scenarios, sensors cannot be deployed manually and are either sent from a safe location or dropped from an aircraft. Mobile devices permit a dynamic deployment reconfiguration that improves the coverage in terms of completeness and uniformity. In this paper we propose a distributed algorithm for the autonomous deployment of mobile sensors called Push & Pull. According to our proposal, movement decisions are made by each sensor on the basis of locally available information and do not require any prior knowledge of the operating conditions or any manual tuning of key parameters. We formally prove that, when a sufficient number of sensors are available, our approach guarantees a complete and uniform coverage. Furthermore, we demonstrate that the algorithm execution always terminates preventing movement oscillations. Numerous simulations show that our algorithm reaches a complete coverage within reasonable time with moderate energy consumption, even when the target area has irregular shapes. Performance comparisons between Push & Pull and one of the most acknowledged algorithms show how the former one can efficiently reach a more uniform and complete coverage under a wide range of working scenarios.     

The electronic structure of oxide-supported tungsten oxide catalysts as studied by UV spectroscopy

The UV spectra of tungsten oxide catalysts supported on alumina, titania and zirconia, and on titania–alumina and titania–zirconia mixed oxides are reported and discussed. Evidence is provided for the different electronic structure of supports and catalysts, which could affect the behavior of the tungsten oxide centres in the different cases. On alumina, tungsten oxide centres are “isolated” by the insulating support, while on titania-based materials they are likely in electronic contact with each other and with Ti centres through the support conduction band. In the case of WOx2013;ZrO₂, the 5d levels of tungsten ions fall just below of the lower energy limit of the support conduction band. This revised version was published online in July 2006 with corrections to the Cover Date.     

Revisiting IS business value research: what we already know,what we still need to know,and how we can get there

The business value of investments in Information Systems (IS) has been, and is predicted to remain, one of the major research topics for IS researchers. While the vast majority of research papers on IS business value find empirical evidence in favour of both the operational and strategic relevance of IS, the fundamental question of the causal relationship between IS investments and business value remains partly unexplained. Three research tasks are essential requisites on the path towards addressing this epistemological question: the synthesis of existing knowledge, the identification of a lack of knowledge and the proposition of paths for closing the knowledge gaps. This paper considers each of these tasks. Research findings include that correlations between IS investments and productivity vary widely among companies and that the mismeasurement of IS investment impact may be rooted in delayed effects. Key limitations of current research are based on the ambiguity and fuzziness of IS business value, the neglected disaggregation of IS investments, and the unexplained process of creating internal and competitive value. Addressing the limitations we suggest research paths, such as the identification of synergy opportunities of IS assets, and the explanation of relationships between IS innovation and change in IS capabilities.     

ATM layouts with bounded hop count and congestion

Summary. In this paper we introduce and analyze two new cost measures related to the communication overhead and the space requirements associated with virtual path layouts in ATM networks, that is the edge congestion and the node congestion. Informally, the edge congestion of a given edge e at an incident node u is defined as the number of VPs terminating at or starting from u and using e, while the node congestion of a node v is defined as the number of VPs having v as an endpoint. We investigate the problem of constructing virtual path layouts allowing to connect a specified root node to all the others in at most h hops and with maximum edge or node congestion c, for two given integers h and c. We first give tight results concerning the time complexity of the construction of such layouts for both the two congestion measures, that is we exactly determine all the tractable and intractable cases. Then, we provide some combinatorial bounds for arbitrary networks, together with optimal layouts for specific topologies such as chains, rings and grids. Received: December 1997 / Accepted: August 2000     

The effect of silicide on ESD performance of transistors

In this paper a new model for localized breakdown in NMOSTs under ESD stress is developed, which accounts for the reduced ESD strength in silicided devices. The model explains the impact of a stabilizing drain resistance on second breakdown current for both silicided and unsilicided protections.     

On the impact of mood on behavior: An integrative theory and a review.

Empirical evidence for effects of moods (both naturally occurring and experimentally manipulated) on behavior is reviewed in terms of an integrative theory: the mood-behavior model (MBM). It is posited that moods can influence behavior via 2 processes: (a) by informational effects on behavior-related judgments and appraisals, which in turn will result in behavioral adjustments (i.e., the informational mood impact on behavior), and (b) by influencing behavioral preferences and interests in compliance with a hedonic motive (i.e., the directive mood impact on behavior). The strength of the informational mood impact depends on moods' effective informational weight for behavior-related judgments and on mood-primed associations. The strength of the directive mood impact is predicted to be jointly determined by 2 variables: the strength of a hedonic motive and the instrumentality of possible acts for affect regulation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)