bluuebunny/crossref_metadata_2025 huggingface dataset:
MPICH-V Project: A Multiprotocol Automatic Fault-Tolerant MPI
Authors: Bouteiller A. , Herault T. , Krawezik G. , Lemarinier P. , Cappello F.
Published: August 2006

High performance computing platforms such as Clusters, Grid and Desktop Grids are becoming larger and subject to more frequent failures. MPI is one of the most used message passing libraries in HPC applications. These two trends raise the need for fault-tolerant MPI. The MPICH-V project focuses on designing, implementing and comparing several automatic fault-tolerant protocols for MPI applications. We present an extensive related work section highlighting the originality of our approach and the proposed protocols. We then present four fault-tolerant protocols implemented in a new generic framework for fault-tolerant protocol comparison, covering a large spectrum of known approaches from coordinated checkpoint, to uncoordinated checkpoint associated with causal message logging. We measure the performance of these protocols on a micro-benchmark and compare them with the NAS benchmark, using an original fault tolerance test. Finally, we outline the lessons learned from this in depth fault-tolerant protocol comparison of MPI applications.
A New Hardware Monitor Design to Measure Data Structure-Specific Cache Eviction Information
Authors: Buck B. R. , Hollingsworth J. K.
Published: August 2006

In this paper, we propose a hardware performance monitor that provides support not only for measuring cache misses and the addresses associated with them, but also for determining what data is being evicted from the cache when a miss occurs. We describe how to use this hardware support to efficiently determine the cache behavior of application data structures at the source code level. We also present the results of a simulation-based study of this technique, in which we examined the overhead, perturbation of results, and usefulness of collecting this information.
Supporting Scalable and Distributed Data Subsetting and Aggregation in Large-Scale Seismic Data Analysis
Authors: Zhang X. , Rutt B. , Çatalyürek Ü. , Kurç T. , Stoffa P. , Sen M. , Saltz J.
Published: August 2006

The ability to query and process very large, terabyte-scale datasets has become a key step in many scientific and engineering applications. In this paper, we describe the application of two middleware frameworks in an integrated fashion to provide a scalable and efficient system for execution of seismic data analysis on large datasets in a distributed environment. We investigate different strategies for efficient querying of large datasets and parallel implementations of a seismic image reconstruction algorithm. Our results on a state-of-the-art mass storage system coupled with a high-end compute cluster show that our implementation is scalable and can achieve about 2.9 Gigabytes per second data processing rate – about 70% of the maximum 4.2GB/s application-level raw I/O bandwidth of the storage platform.
Diet: A Scalable Toolbox to Build Network Enabled Servers on the Grid
Authors: Caron E. , Desprez F.
Published: August 2006

Among existing grid middleware approaches, one simple, powerful, and flexible approach consists of using servers available in different administrative domains through the classical client-server or Remote Procedure Call (RPC) paradigm. Network Enabled Servers implement this model also called GridRPC. Clients submit computation requests to a scheduler whose goal is to find a server available on the grid. The aim of this paper is to give an overview of a middleware developed by the GRAAL team called DIET (for Distributed Interactive Engineering Tool-box). DIET is a hierarchical set of components used for the development of applications based on computational servers on the grid.
Steady-State Scheduling of Multiple Divisible Load Applications on Wide-Area Distributed Computing Platforms
Authors: Marchal L. , Yang Y. , Casanova H. , Robert Y.
Published: August 2006

Divisible load applications consist of an amount of data and associated computation that can be divided arbitrarily into any number of independent pieces. This model is a good approximation of many real-world scientific applications, lends itself to a natural master-worker implementation, and has thus received a lot of attention. The critical issue of divisible load scheduling has been studied extensively in previous work. However, only a few authors have explored the simultaneous scheduling of multiple such applications on a distributed computing platform. We focus on this increasingly relevant scenario and make the following contributions. We use a novel and more realistic platform model that captures some of the fundamental network properties of grid platforms. We formulate the steady-state multi-application scheduling problem as a linear program that expresses a notion of fairness between applications. This scheduling problem is NP-complete and we propose several heuristics that we evaluate and compare via extensive simulation experiments. Our main finding is that some of our heuristics can achieve performance close to the optimal and we quantify the trade-offs between achieved performance and heuristic complexity.
Realistic Large-Scale Online Network Simulation
Authors: Liu X. , Chien A. A.
Published: August 2006

Large-scale network simulation is an important technique for studying the dynamic behavior of networks, network protocols, and emerging classes of distributed applications (e.g. Grid, peer-to-peer, etc.) Large scale and realism are two critical requirements for network simulations of Grid application studies. Our work here extends previous efforts in three key ways. First, we study networks 100 times larger than in our previous studies (20000 routers). Second, at this scale, we study realistic network structures (100 ASs, BGP4 and OSPF routing) versus flat OSPF routing. Finally, we describe and evaluate a new profile-based load-balancing approach called hierarchical profile-based load balance.

Our extensive large-scale experiments with profile-based load balance (PROF) on flat-routed (OSPF) networks show that PROF outperforms several other techniques based on topology and static application information. However, these results and those for multi-AS networks motivate our invention of a new hierarchical technique (HPROF) which clusters network nodes to achieve a desired minimum link latency (MLL), a key determinant of simulation parallelism, then applies the graph partitioner. HPROF explicitly controls the trade-off between simulation efficiency and available parallelism, producing robust and superior performance for large-scale networks, including both single-AS and multi-AS networks. HPROF can improve load imbalance by 40%, and reduce the simulation time by about 50% in our 20000 router simulations executed on 128-node clusters. The parallel efficiency achieved by these simulations is over 40%, providing substantial capabilities for simulating large networks. In summary, these advances demonstrate that realistic large-scale network simulation for networks of 20000 routers (comparable to a large Tier-1 ISP network such as AT&T) can be accomplished with our system.

To demonstrate the capabilities of our simulation tool, we simulate a large-scale Denial-of-Service attack in a large-scale network with 10000 routers organized as 40 Autonomous Systems. The simulation includes over 400 live application processes, the DoS attack and application entities, and generates aggregate traffic of over 6 Gbps.
Organizational Use of Evaluations
Authors: Hansson Finn
Published: August 2006

Today's organizations perform evaluations in order to demonstrate their trustworthiness to the outside world and in order to produce information for use by management. In the planning and application of specific evaluations, different participants or stakeholders very often have different or conflicting agendas. In recent years, the use of evaluations in organizations has grown rapidly and we have witnessed the rise of a new bureaucratic instrument in the realm of knowledge production: the internal evaluation. Such evaluations produce a set of data as part of the evaluation process, and the long-term impact of the use of these data on organizational activities is not normally given serious consideration when the use of evaluations in organizations is discussed. These evaluations have become a major factor in the management of organizations, but the academic literature on evaluation very rarely discusses the impact of this instrument of governance on the behaviour and activity of members of the organization.
Who Owns the Theory of Change?
Authors: Sullivan Helen , Stewart Murray
Published: August 2006

Policy evaluations in the UK have increasingly espoused a ‘Theories of Change’ (ToC) approach, drawing on North American experiences. Features of ToC include the expectation that all affected stakeholders will be involved in developing, agreeing, monitoring and evaluating a relevant theory for the proposed intervention, and the assumption that widespread stakeholder involvement will extend ownership of the intervention to achieve ‘total ownership’ and also improve attribution. Drawing on the experiences of three English evaluations (Health Action Zones, New Deal for Communities and Local Strategic Partnerships), this article examines the possibilities and limitations associated with the achievement of ‘total ownership’. Analysis reveals some important differences between the English and North American contexts and leads to the development of alternative models of ownership including ‘elite’,‘evaluator’,‘principal’ or ‘community’ ownership. The article concludes that if these models are more realistic than ‘total ownership’ in the English policy environment then this has implications for the appropriate application of ToC.
Evaluation in Multi-Actor Policy Processes
Authors: Van Der Meer Frans-Bauke , Edelenbos Jurian
Published: August 2006

Two main functions of evaluation are enabling accountability and collective learning. Both of these – and their combination – run into diverse complications when applied in complex multi-actor policy processes. The article explores these complications and illustrates them with examples from the field of spatial policy. In doing so, a third function of evaluation in such contexts is identified, viz. evaluation as an instrument of co-operation. Next, a number of theoretical ideas, supported by empirical research, are proposed in order to understand better when, why and how evaluation contributes to complex multi-actor policy processes. Based on these insights, some principles are elaborated for the development of constructive evaluation arrangements. The authors suggest that co-operation is a precondition for the preservation of accountability and learning functions of evaluation in multi-actor settings.
Performance Measurement
Authors: De Lancer Julnes Patria
Published: August 2006

For much of the 20th century, accountability and performance measurement in the public sector centered on financial accounting, focusing on questions of how much money was spent and on what. Improved performance was mostly defined in terms of managerial efficiency. Recently, however, accountability has taken on a broader meaning to include the results of public actions. This emphasis on ‘managing for results’ has yielded the GPRA (Government Performance and Results Act) approach in the US government. Efforts to promote accountability with this emphasis, however, have occasioned a backlash. In particular, some have criticized the information that results from performance measurement systems as inadequate for the task of guiding government resource allocation decisions. That task, say critics, is the domain of program evaluation. In reviewing the contributions of performance measurement and its limitations, this article concludes that accountability needs are better addressed when program evaluators and performance measurement practitioners cooperate.
Dual Level Evaluation and Complex Community Initiatives
Authors: Allen Meg , Black Mary
Published: August 2006

In the last decade ‘dual level’ evaluation, where evaluation is carried out at both a national and local level, has become increasingly common. It is often used as a way of evaluating complex government initiatives that operate across agency boundaries. Using ‘dual level’ evaluation is one way to address the complexity of such wide-ranging initiatives, by evaluating both for local development and national accountability. Yet the design of these evaluations has varied widely in the UK and the effectiveness of the different designs, and of the model itself, has not been examined. Using Sure Start as a case study, the article highlights some of the difficulties that can arise in dual level evaluations. It is argued that there is a need for a high level of integration between national and local evaluators and that dual models of evaluation should utilize the knowledge of local evaluators in the collection and interpretation of data.
The intent and extent of multimarket contact
Authors: Greve Henrich R.
Published: August 2006

Multimarket research studies the causes and consequences of firms meeting each other in multiple markets, and has found evidence that multimarket contact reduces competitive pressures. Recent work has examined whether multimarket contacts are sought strategically or entered coincidentally, with some papers finding a large role of coincidental entry. The finding is puzzling given the well-documented benefits of multimarket contact. This article takes advantage of advances in multimarket theory and measurement to analyze market entries, and finds that strategic entry is seen when the intent and extent of multimarket contacts are considered, but also that managers appear to be risk-averse when establishing multimarket contacts.
The effects of administrative innovation implementation on performance: an organizational learning approach
Authors: Naveh Eitan , Meilich Ofer , Marcus Alfred
Published: August 2006

This study defines organizational learning as greater cognizance of action-outcome relationships and the effects that environmental events have on these relationships. It shows that two learning mechanisms, adaptation-in-use and change catalysis, are key factors inrealizing gains from the implementation of administrative innovations. Adaptation-in-use denotes ongoing adjustment of the innovation to the organizational context. Change catalysis means that implementation is an occasion for rethinking the way the organization does business and an opportunity to introduce additional new practices and to innovate. A total of 1150 facilities belonging to 885 companies that implemented the worldwide quality standard ISO 9000 participated in this study. Results demonstrate that the effects of implementation of this administrative innovation on performance are curvilinear; both too little and too much implementation have a negative effect on performance. The two learning mechanisms moderate the relationship between implementation of the administrative innovation and subsequent performance, such that implementation is associated with higher performance when adaptation-in-use and change catalysis are high rather than low.
Expatriate Preparation: A Critical Analysis of 25 Years of Cross-Cultural Training Research
Authors: Littrell Lisa N. , Salas Eduardo , Hess Kathleen P. , Paley Michael , Riedel Sharon
Published: August 2006

Although much research in the 1960s and 1970s was devoted to cross-cultural issues such as expatriate employment, researchers moved away from doing cross-cultural research in order to direct their efforts toward the hot topics of the time. However, the past few decades have seen an exponential increase in the globalization of our economy, and this ever-increasing globalization has made the need for cross-cultural research salient once again. In the past decade alone, there has been an explosion of research examining the components and effectiveness of cross-cultural training (CCT) for expatriate preparation. Thus, the ultimate purpose of this literature review is to present the past 25 years of CCT research relevant to expatriate preparation by examining the following: the need for CCT research, the deficiencies in past research, typical training components, training delivery, theory pertaining to CCT, potential moderators of the relationship between CCT and expatriate performance, the effectiveness of CCT in enhancing expatriate performance, suggestions for future research, and strategies for improving CCT implementation and research. After reviewing the past 25 years of CCT research, it is evident that CCT is effective in facilitating success on expatriate assignments. However, additional empirical research is needed on moderators, expatriate selection, training program supplements, theoretical frameworks, methodological challenges, and the customization of CCT to assignment objectives.
Advances in the Treatment of Prolactinomas
Authors: Gillam Mary P. , Molitch Mark E. , Lombardi Gaetano , Colao Annamaria
Published: August 2006

Prolactinomas account for approximately 40% of all pituitary adenomas and are an important cause of hypogonadism and infertility. The ultimate goal of therapy for prolactinomas is restoration or achievement of eugonadism through the normalization of hyperprolactinemia and control of tumor mass. Medical therapy with dopamine agonists is highly effective in the majority of cases and represents the mainstay of therapy. Recent data indicating successful withdrawal of these agents in a subset of patients challenge the previously held concept that medical therapy is a lifelong requirement. Complicated situations, such as those encountered in resistance to dopamine agonists, pregnancy, and giant or malignant prolactinomas, may require multimodal therapy involving surgery, radiotherapy, or both. Progress in elucidating the mechanisms underlying the pathogenesis of prolactinomas may enable future development of novel molecular therapies for treatment-resistant cases. This review provides a critical analysis of the efficacy and safety of the various modes of therapy available for the treatment of patients with prolactinomas with an emphasis on challenging situations, a discussion of the data regarding withdrawal of medical therapy, and a foreshadowing of novel approaches to therapy that may become available in the future.
Jekyll and Hyde: Two Faces of Cannabinoid Signaling in Male and Female Fertility
Authors: Wang Haibin , Dey Sudhansu K. , Maccarrone Mauro
Published: August 2006

Mammalian reproduction is a complicated process designed to diversify and strengthen the genetic complement of the offspring and to safeguard regulatory systems at various steps for propagating procreation. An emerging concept in mammalian reproduction is the role of endocannabinoids, a group of endogenously produced lipid mediators, that bind to and activate cannabinoid receptors. Although adverse effects of cannabinoids on fertility have been implicated for years, the mechanisms by which they exert these effects were not clearly understood. With the identification of cannabinoid receptors, endocannabinoid ligands, their key synthetic and hydrolytic pathways, and the generation of mouse models missing cannabinoid receptors, a wealth of information on the significance of cannabinoid/endocannabinoid signaling in spermatogenesis, fertilization, preimplantation embryo development, implantation, and postimplantation embryonic growth has been generated. This review focuses on various aspects of the endocannabinoid system in male and female fertility. It is hoped that a deeper insight would lead to potential clinical applications of the endocannabinoid signaling as a target for correcting infertility and improving reproductive health in humans.
A Study of Natural Neighbour Interpolation and Its Application to Automotive Engine Test Data
Authors: Tily R , Brace C J
Published: August 2006

Natural neighbour interpolation (NNI) is a method of interpolation, used primarily with irregular spatial data, which has a number of attractive features. This paper discusses NNI, its related Voronoi and Delaunay structures, and its suitability for processing automotive engine test data. Tests show that NNI can successfully interpolate randomly scattered engine test data without the need for an intermediate gridding operation. This allows data to be clustered tightly in some areas and sparsely scattered in others. NNI also shows itself to be a very accurate interpolation method, with better performance than commonly used techniques.

Although NNI is available in a small number of specialized non-automotive software packages, there is currently no generally available implementation in mathematical software packages, such as Math Works's MATLAB, that could be used in a wide number of applications, including automotive. A number of MATLAB functions and programs, that implement NNI, have been developed by the authors and are introduced here.
A Numerical Scheme for Dynamic Liquid Sloshing in Horizontal Cylindrical Containers
Authors: Dai Liming , Xu Liang
Published: August 2006

A numerical scheme for the analysis of liquids sloshing in horizontal cylindrical rigid containers is presented. The governing equations of the liquid are transformed by three continuous coordinate transformations to avoid the use of interpolation of the boundary conditions on the curved walls and capturing of the free surface, as well as to gain convergence and computational stability of numerical computation. The efficiency of the proposed method is demonstrated by numerical simulations using the finite difference method for two-dimensional circular containers and three-dimensional cylindrical containers. The method can be used to simulate the liquid sloshing under normal highway operating conditions when lateral accelerations are below the roll-over threshold. This approach can be extended to containers with walls of arbitrary shapes.
Mechanical Behaviour Simulation for Synchromesh Mechanism Improvements
Authors: Lovas L , Play D , Marialigeti J , Rigal J F
Published: August 2006

This paper deals with the synchromesh behaviour of the manual car gearbox. Firstly, the state of the art on Borg-Warner-type synchronizers is presented. Then, the gear-changing process is studied and eight main operating phases are defined. The phases are described using classical tribological, mechanics, and thermodynamics theories. Models are interconnected to describe synchronizer behaviour and they are included in a numerical simulation software. Measured data are compared with the results of simulation software. Then, stick-slip phenomenon during gear changing is studied. Stick-slip is supposed to be present in two contact zones: sleeve splines and the synchronizer cone. The effects in both zones are discussed. Finally, the double bump phenomenon is studied. Double bump is assumed to be the maximum axial operating force coming from short successive phases at the end of the gear-changing process. Due to the angular integer division of splines and to the non-definite angular position of mechanical parts, sliding sleeve displacement into the ring and gear claw clutch splines gives secondary angular rotation and large increases in the axial operating force. The model can explain large variations and random dispersion of the measured double bump force peaks.
An Investigation on a New Reduced Chemical Kinetic Model of n-heptane for HCCI Combustion
Authors: Yao Mingfa , Zheng Zhaolei
Published: August 2006

Detailed chemical kinetic calculations coupled with computational fluid dynamics simulations of chemically reacting flows are still unrealistic as the basis for a parametric simulation tool because they require a long central processing unit time. In this paper, a new reduced model of n-heptane has been developed on the basis of detailed mechanism by sensitivity analysis and oxidation path analysis in homogeneous charge compression ignition (HCCI) combustion. The new reduced mechanism consists of 35 species and 41 reactions, and it is effective in simulating HCCI engine combustion process. The results show that it gives predictions similar to the detailed model in ignition timing, in-cylinder temperature, and pressure. Furthermore, the reduced mechanism can be used to simulate the boundary conditions of partial combustion in good agreement with the detailed mechanism.
The Role of Muscle Tensing on the Force-Deflection Response of the Thorax and a Reassessment of Frontal Impact Thoracic Biofidelity Corridors
Authors: Kent R W , Bass C R , Woods W A , Salzar R S , Lee Sang-Hyun , Melvin J
Published: August 2006

This paper evaluates how muscle tensing changes the structural response of the dynamically loaded thorax. Nine porcine thoraces with both ventral (supine) and dorsal (prone) loading were used to quantify the effect. Muscle tensing was assessed using repeated tests on a subject with and without forced muscle contraction. Dynamic (53.9 ± 2.9 cm/s) and quasistatic tests were performed with a potentiometer and load cells to calculate effective thoracic stiffness. The results show that the effect of muscle tensing decreases with increasing chest deflection, a fact which is supported by the limited human data available. The peak force increases with muscle tensing for chest deflection levels up to about 20 per cent, after which the peak force changes negligibly when the muscles are tensed. The shape of the force-deflection curve and therefore the work done by the deforming thorax do, however, depend upon muscle tensing regardless of the peak deflection level attained. A simplified finite element model is used to elucidate the mechanisms for the experimental findings. This model shows that the changes in force-deflection response of the thorax that occur with muscle tensing are due primarily to the increased modulus of the muscle tissue itself, rather than to any stiffening effect from pretensioning the muscle membrane around the bony structure. The findings are discussed relative to current thoracic biofidelity corridors, which include an adjustment to account for muscle tensing.
Automotive Adsorption Air Conditioner Powered by Exhaust Heat. Part 2: Detailed Design and Analysis
Authors: Lambert M A , Jones B J
Published: August 2006

This paper presents the detailed design and analysis of an automotive adsorption air conditioner, particularly the critical components, the adsorbent canisters, or adsorbers, and the exhaust-to-oil heater. The best adsorbent-refrigerant combination is activated carbonammonia. For the adsorber shell and tubes, austenitic stainless steel 304 has sufficient fatigue strength at 300 °C and is compatible with ammonia. Annular fins and wool inside the adsorbers are nickel-plated low-carbon steel. The exhaust-to-oil heater is of ferritic stainless steel and can withstand heating beyond 400 °C. The adsorbers, oil heater, and refrigerant reservoir are sized on the basis of the cooling requirement for a subcompact car during a typical commute, as defined in Part 1. The refrigerant reservoir provides immediate cooling upon start-up of a cold engine while the exhaust system and adsorbers are heating. A thermal reservoir containing phase-change material (PCM) allows full recharging of the refrigerant reservoir after a 20 min commute. Detailed thermal, fluidic, and mechanical analyses of the adsorbers and oil heater are performed. Eliminating the mechanical compressor increases fuel mileage by 14-18 per cent for mid-size, compact, and subcompact cars, or 4.6-6.0 per cent annually, given a 4 month cooling season. The adsorption system adds ∊3.5 per cent to vehicle mass, which reduces fuel mileage by ∊2.1 per cent. Thus, the annual benefit/cost ratio in terms of fuel mileage ranges from 2.3 to 2.7.
Analysis of the Disbond Effect on the Stress Intensity Factor Variation for Repaired Cracks with Bonded Composite Patch
Authors: Amiri A , Bouiadjra B Bachir , Serier B , Belhouari M
Published: August 2006

The aim of this study is to analyse, by the finite-element method, the disbond effect on the variation of the stress intensity factor (SIF) at the crack tip in an aluminium sheet repaired with a boron/epoxy patch. The effects of the width and the height of the disbond on the variation of the SIF at the crack tip are highlighted. The obtained results show that the presence of the disbond area increases the SIF of the repaired crack and the rate of this increase depends primarily on the size of the disbond area. The obtained results allow the development of an analytical model of the asymptotic SIF, which takes account of the disbond effect. This model adds the effect of the disbond of the adhesive layer to the well-known Rose model.
Modelling and Prediction of the Diglycidyl Ether Bisphenol-A/2,2′-dimethyl-4,4′-methylenebis (cyclohexylamine) Reaction
Authors: Fouchal F , Harris R A , Knight J A G , Dickens P M
Published: August 2006

Differential scanning calorimetry is used for the analysis and quantitative evaluation of the reaction between diglycidyl ether bisphenol-A and 2,2′-dimethyl-4,4′-methylenebis (cyclohexylamine) according to changes in concentrations of reactants and products. First, this concerned determining the variation in enthalpy of reaction over time for different curing temperatures, plotting of glass transition temperatures versus time, calculation of a polynomial for glass transition temperature against fractional conversion, and the production of plots of fractional conversions versus time. Secondly, the fractional conversion data were used for the kinetic analysis. The line of best fit to these data points revealed an essentially logarithmic relationship that was used to evaluate the reaction rate, d x/d t corresponding to the conversion x, then plot the changes in concentrations (in moles) of all the reactants and products involved in the reaction versus time. This produced a quantitative prediction of the reaction over the curing period.
Quasi-Static and Low-Velocity Impact Failure of Aluminium Honeycomb Sandwich Panels
Authors: Foo C C , Chai G B , Seah L K
Published: August 2006

This article presents an extensive experimental and numerical investigation of aluminium sandwich plates subjected to quasi-static loading and low-velocity impact. The objective of this research is to understand and, ultimately, predict the initiation and progression of damage in an aluminium sandwich plate subjected to low-velocity impact. The static indentation and impact problems were analysed using the commercial finite-element software, ABAQUS. Quasi-static indentation tests and low-velocity drop weight tests were conducted to characterize the failure and to determine the extent of damage observed in aluminium sandwich plates. Comparison of the numerical load history, specimen damage area, and residual indentation with experimental results demonstrated the ability of the modelling methodology to capture the impact characteristics.

Experimental results also indicated that the damage mode experienced on the impacted facesheet may be correlated to the energy absorbed by the plate during the impact event and the static failure energy. A numerical parametric study was conducted to determine the effect of various geometric parameters, such as foil thickness and cell size, on the damage resistance of the core and impacted facesheet. Findings showed that the energy absorbed during impact is independent of the core density. However, denser cores exhibited greater peak loads but experienced smaller damage profiles in the core and impacted facesheet.
Solid Surface Enhancement Effects on Chemiluminescence. I. Diaryloxalate and Filters as Media Solids
Authors: Yoshinaga Tetsutaro , Morita Michihiko , Wada Ken-ichi , Ichimura Teijiro , Hiratsuka Hiroshi
Published: August 2006

Solid-surface enhancement effects on chemiluminescence were observed using diaryloxalate bis[3,4,6-trichloro-2-(pentyloxycarbonyl)phenyl] oxalate, fluorophore[1-chloro-9,10-bis(phenylethynyl)anthracene], hydrogen peroxide and solids (filters) as media. An especially strong emission was observed when glass fiber filters were used. It is suggested that both the chemical composition and the surface physical properties of the solids affect luminescence. The effects of humidity and temperature on chemiluminescence were also examined. A relative humidity of 50% (at 30 °C) gave the highest luminescent intensity. A power functional relation of one hundredth lifetime (t1/100) and the temperature(T) was obtained.
Studies on the Reactions of CH (v = 0 and 1) with NO and O2
Authors: Okada Satoru , Yamasaki Katsuyoshi , Matsui Hiroyuki , Saito Ko , Okada Kazumasa
Published: August 2006

Rate constants for the reactions of CH(X2Π : v = 0,1) with NO and O2 are measured under pseudo-first-order conditions at 297 ± 5 K. CH(X2Π : v = 0,1) radicals are generated by excimer laser photolysis of CHBr3 and (CH3)2 CO at 193 nm, and detected by the laser-induced fluorescence (LIF) technique. The overall rate constants obtained at the total pressure of 20 Torr Ar are: kNO(v = 0) = (1.6 ± 0.2) × 10−10, kNO(v = 1) = (1.3 ± 0.6) × 10−10, kO2(v = 0) = (3.5 ± 0.3) × 10−11, and kO2(v = 1) = (3.4 ± 0.8) × 10−11 (cm3 molecule−1 s−1).

No apparent pressure dependence is indicated for the rate constants over the pressure range of 5—50 Torr Ar for CH + NO, and 5—30 Torr Ar for CH + O2 reactions, respectively.

The reaction mechanisms are discussed based on the quantum mechanical calculations of the potential energy surfaces of CH + NO and CH + O2 systems.
The Catalytic Activity and Selectivity of Some Metallic Glasses in the Hydrogenation of 1-Hexene
Authors: Mahmoud Sabri S , Giessen Bill C
Published: August 2006

The catalytic activity and selectivity of twenty one amorphous alloy ribbons were examined in the hydrogenation of 1-hexene. The amorphous alloys are of higher activity but of similar hydrogenation selectivity to the crystalline ones. Pd-based amorphous alloy ribbons, in particular Pd80Si20, are of a relatively high catalytic activity and of low selectivity towards hydrogenation. Fe20Ni60P20 amorphous alloy is a highly hydrogenation selective catalyst. Incorporation of Pd in the Fe–Ni–B alloy doubled its activity and reduced its hydrogenation selectivity by 30%. Alloying P, instead of B, with Fe and Ni significantly increased the hydrogenation selectivity of this Fe–Ni based alloy; the hydrogenation selectivity was increased from 85% for Fe20Ni60B20 to 93% for Fe20Ni60P20.
Solvent Effects on Electronic States of Phthalocyanines
Authors: Harazono Toshie , Takagishi Iwao
Published: August 2006

The absorption spectra of a π–π* transition (the Q band) of titanium (IV) oxide phthalocyaninate (TiOpc) and phthalocyanine (H2pc) were measured in various organic solvents. It has been shown that the wavelength of the π–π* transition is dependent on 1) the permanent dipole moment of the solvent, 2) the coordination of the solvent, and 3) the dispersion force and induced dipole moment of the solvent. A single π–π* peak and its significant red-shift in the absorption spectrum of H2pc in trifluoroacetic acid (TFA) suggested a protonation of the inner nitrogen atoms, leading to H4pc2+. TiOpc in TFA was cleaved, followed by the release of H2pc. The overall reaction was proposed to be as follows; TiOpc + 4CF3COOH Ti(CF3COO)4 + H2O + H2pc.
An NMR Study of Substituted Pyridine-Butyllithium Adducts
Authors: Yoshino Akihiro , Nakamura Norimasa , Takahashi Kensuke
Published: August 2006

The 1H and 13C NMR spectra of the title adducts have been observed in THF and HMPA solutions. The charge distributions in the adducts calculated from the 13C chemical shifts indicated that the 2-pyridyl ring accommodated at least about 25% negative charge at the 6-position of the adduct skeleton, while the phenyl ring gave only a 4% change at the same position. For the 2,2′-bipyridine-butyllithium adduct two isomers (E and Z) were confirmed by 1H and 13C NMR, indicating that the bond between the two rings has a partial double-bond character. However, for phenylpyridine–butyllithium adducts, the rotation of the phenyl group was not restricted, even at −80 °C.
Structure of Hexatitanooctadecatungstodigermanate
Authors: Yamase Toshihiro , Ozeki Tomoji , Sakamoto Hiroshi , Nishiya Shigeki , Yamamoto Akihiro
Published: August 2006

The structure of a dimeric Keggin-typed polyoxotungstate, [Ge2Ti6W18O77]14−, was investigated by X-ray diffractometry and 183W NMR spectroscopy. K9H5[Ge2Ti6W18O77]·16H2O crystallizes in triclinic  a = 17.582(4), b = 22.139(5), c = 12.960(2) Å, α = 101.26(2), β = 94.07(2), γ = 109.20(2)°, V = 4622(4) Å3. The D3d [Ge2Ti6W18O77]14− anion, which gives two 183W NMR resonances at −107.45 and −127.76 ppm, consists of two C3v  α-A-[GeTi3W9O40]10− moieties fused together at the terminal O atoms of the 6 Ti atoms.
Unidirectional Electron Transfer at Self-Assembled Monolayers of 11-Ferrocenyl-1-undecanethiol on Gold
Authors: Sato Yukari , Itoigawa Hiroyuki , Uosaki Kohei
Published: August 2006

The electron-exchange reaction between the ferrocenyl group of self-assembled monolayers of 11-ferrocenyl-1-undecanethiol on gold electrodes and Fe(III) species in solution is studied. The monolayer acts as an effective electron-transfer mediator for the reduction of Fe(ClO4)3 but inhibits the oxidation of Fe(ClO4)2 in HClO4 and NaClO4 solution. This behavior is also observed in HClO4 solutions containing FeIII(edta) but only when the concentration of HClO4 is higher than 0.5 M. Absorption spectra and spectroelectrochemical and electrochemical measurements show that FeIII(edta) dissociates in highly acidic solutions and generates Fe3+aq, which acts as an electron-accepting species.
Photocatalytic Reaction of Ethanol over Titanium Diselenide
Authors: Iseda Kozo , Osaki Toshihiko , Taoda Hiroshi , Yamakita Hiromi
Published: August 2006

A suspension of TiSe2 in ethanol was illuminated with ultraviolet light in an atmosphere of Ar, air, or O2 at 298 K. The main products were acetaldehyde, acetaldehyde diethyl acetal (acetal), acetic acid, water, hydrogen, ethylene, methane, and carbon dioxide. Each yield of the products under air or O2 was higher than under Ar, except for that of hydrogen and ethylene. Platinum under an O2 atmosphere exerted its effect for producing CH3COOH, acetal, CO2, CH3CHO, CH4, and H2O, while under Ar it contributed to generating CO2, CH4, and H2. No effect of Pt was observed for generating C2H4 under either an atmosphere of Ar or O2.
Visible-Light Induced Photocatalysis of Partially Fluorinated Poly(p-phenylene) and Related Linear Phenylene Derivatives
Authors: Maruo Katsuya , Yamada Kazuyori , Wada Yuji , Yanagida Shozo
Published: August 2006

As a partially fluorinated poly(p-phenylene) derivative, yellow powder PF-PPP-n with high solubility in organic solvents was prepared as a mixture of oligomers by nickel-catalyzed polycondensation of the Grignard reagent from 1-bromo-2,4,6-trifluorobenzene. PF-PPP-n shows photocatalytic activity for reduction of water to H2, carbonyl compounds to alcohols, and dimethyl maleate and fumarate to the succinate under visible-light (λ > 400 nm) irradiation in the presence of triethylamine as a sacrificial electron donor. The photocatalysis was compared with those of other related fluorinated linear aromatics such as perfluorinated poly(p-phenylene sulfide) (F-PPS-n), perfluorinated poly(p-phenylene) (F-PPP-n). Their spectral characteristics and photocatalysis are discussed on the basis of the semiempirical molecular orbital calculations.
Extraction and Separation Studies of Bismuth(III) and Antimony(III) with Tris(2-ethylhexyl)phosphate
Authors: Barve Anirudha D , Desai Ganesh S , Shinde Vijay M
Published: August 2006

Separation of bismuth(III) from lead, antimony, gold, and tellurium and that of antimony(III) from copper, bismuth, and lead is achieved by selective extraction of bismuth(III) and antimony(III) from halide solutions into tris(2-ethylhexyl)phosphate (TEHP) dissolved in toluene or xylene. The extracted species are evaluated by log D–log C plots. The method is applicable to the analysis of some ‘real’ samples. The separation and determination takes only 20 minutes.
A Rapid Spectrophotometric Determination of Molybdenum(VI) Using 2′-Hydroxyacetophenone Benzoylhydrazone
Authors: Dass Rameshwar , Mehta Jaswant Ram
Published: August 2006

2′-Hydroxyacetophenone benzoylhydrazone (HABH) has been used for the first time as an analytical reagent for determination of molybdenum spectrophotometrically. Molybdenum (VI) in presence of large number of cations, anions, and complexing agents except oxalate and borate, forms a yellow complex with HABH extractable into carbon tetrachloride from weakly acidic solution. As many as 31 cations, 15 anions, and complexing agents were studied. The absorbance of the complex was measured at 390 nm. The color was stable for more than 18 h. The system conformed to Beer’s law over the concentration range of 1.28 to 13.8 μg of molybdenum per cm3. The procedure is simple, selective, reproducible and takes < 10 min in a single determination of molybdenum in large number of synthetic samples.
A Voltammetric Study on the One-Electron Redox Processes of the Dawson-Type Heteropolymolybdate Complexes
Authors: Himeno Sadayuki , Maeda Kohji , Osakai Toshiyuki , Saito Atsuyoshi , Hori Toshitaka
Published: August 2006

The electrochemical behaviors of the Dawson-type heteropolymolybdate anions, [S2Mo18O62]4−, [P2Mo18O62]6−, and [As2Mo18O62]6− were investigated at the glassy carbon (GC) electrode. In CH3CN where no protonation accompanies reduction, the voltammogram of the [S2Mo18O62]4− anion consists of four one-electron redox waves followed by an ill-defined wave while the [P2Mo18O62]6− and [As2Mo18O62]6− anions exhibit two one-electron redox waves; the one-electron waves are reversible and diffusion-controlled. The Dawson anions undergo successive two-electron reductions under the conditions where protonation can accompany reduction. The effect of the presence of acid on the voltammetric behaviors has also been discussed.
“In-situ” Quartz Crystal Microbalance Responses and Electrochemistry Regarding Langmuir–Blodgett Film of Viologen Polyion Complex on the Electrode Surface
Authors: Oyama Noboru , Ikeda Shin , Hatozaki Osamu , Shimomura Masatsugu , Mishima Kumi , Nakamura Sadako
Published: August 2006

The electrochemical behavior and the response of the quartz crystal microbalance(QCM) for the Langmuir–Blodgett(LB) viologen film have been examined. LB monolayers employed are prepared by electrostatically fixing the viologen monolayer containing the alkyl chain moiety on the poly(potassium 1-sulfatoethylene). The number of monolayers accumulated on the polycrystalline Au electrode of a piezoelectric quartz crystal was controlled by changing the general vertical dipping times. The QCM frequency response for the first reduction scan of viologen dication (V2+) to monocation radical (V+•) shows extremely large frequency increase, qualitatively indicative of mass loss, viscoelasticity decrease, or mechanical stress decrease during the reduction. A frequency increase during the second reduction scan is also observed, although not as large as for the first scan. The frequencies increase continuously with increasing number of scans and the steady-state responses can only be obtained after many repetitive potential scans. The results of the conductance spectra measurements of the quartz crystal/LB film composite resonator are interpreted as break-in and/or an increase of aggregation of the orientated structure during potential scans. The cyclic voltammetric wave obtained in the potential range 0 to −0.7 V vs. sodium chloride saturated calomel electrode has the characteristics of a simple, one electron transfer between V2+ and V+•, being chemically reversible process. The subsequent cyclic voltammogram responses obtained after the first cycle of potential scan are nearly identical for some hours, in contrast to the responses of the QCM. It is shown that structural change of the organized film dose not have a significant influence on the shape of the electrochemical response but does have an effect on the frequency response of the QCM.
Viscosity and Dissociation Mechanism of a Cryolite Flux, Na3AlF6, during the Growth of Corundum Single Crystals
Authors: Watanabe Koichi
Published: August 2006

The viscosities of the Na3AlF6–Al2O3 system, including Al2O3 of 0, 5, 10, and 15 wt%, during the growth of corundum single crystals at 1050 °C were measured by the oscillating disk method, and used with Hallett’s equation. Although the viscosity in such a system progressively increased with an increase in the Al2O3 concentration, from 1.57 cP (0 wt%) to 1.68 cP (10 wt%) at 1050 °C, at 15 wt% it steeply increased to 2.40 cP. A plot of the logarithmic viscosity vs. the reciprocal absolute temperature gave a linear relation in the respective systems. The values of the mean molar volume and the activation free energy (ΔG*) of the flow unit in a system including 15 wt% Al2O3 were calculated to be approximately 22.4 ml mol− at 1050 °C and 12.74 kcal mol−1, respectively. The dissociated ionic species and its mechanism in the molten state of such a system are discussed in terms of the free-energy-limited theory deduced from the reaction rate theory; the steep increment of the viscosity in a system containing Al2O3 of more than 10 wt% is conjectured to be caused by a clustering state of dissociated Al2O3.
Synthesis and Characterization of Thiolate-Bridged Dinuclear Nickel(II) Complexes with Thioether Pendant Arms
Authors: Mikuriya Masahiro , Handa Makoto , Shigematsu Shinji , Funaki Shunji , Fujii Toshinori , Okawa Hisashi , Toriumi Koshiro , Koshiba Takashi , Terauchi Hikaru
Published: August 2006

Thiolate-bridged dinuclear nickel(II) complexes with N-[2-(2-pyridyl)ethyl]-N-[2-(methylthio)ethyl]-2-aminoethanethiol (HLa) or N-[2-(2-pyridyl)ethyl]-N-[2-(ethylthio)ethyl]-2-aminoethanethiol (HLb), [Ni2(La)2](ClO4)2 (1) and [Ni2(Lb)2](ClO4)2 (2), have been synthesized and characterized by elemental analyses, infrared and electronic spectra, magnetic susceptibilities (80—300 K), and XANES. The crystal structures of 1 and 2 were determined by the single-crystal X-ray diffraction method at 118 and 293 K, respectively. The cation molecule has a thiolate-bridged dinuclear structure, in which each nickel ion is essentially coordinated by a square-planar N2S2 donor set with a weak apical coordination of the pendant thioether group. The magnetic and spectral properties are discussed based on the crystal structures.
Liquid Chromatography with Aminopropylsilica Gel Modified by Heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin Derivative
Authors: Kuroda Yasuhisa , Kato Teru , Ogoshi Hisanobu
Published: August 2006

New stationary phases modified by heptakis(2,3,6-O-trimethyl)-β-cyclodextrin were prepared and tested as HPLC columns. The results show that these stationary phases exhibit significant chiral separation abilities for various types of aromatic compounds under reversed-phase conditions. Acetylation and propionylation of the residual amino groups on silica gel improve the retention capacity of the stationary phase and results in better chromatographic chiral separation. One of the most possible reasons for this superior chiral separation observed for the acylated stationary phases is considered to be the increased local concentration of the solutes on the hydrophobic surface of the stationary phase, which increases the possibility for the contact of solutes with the outside of cyclodextrin fixed on the silica gel.