bluuebunny/crossref_metadata_2025 huggingface dataset:
Voltammetric Determination of Metals in Copper Alloys at Trace and Ultratrace Concentrations
Authors: Locatelli Clinio , Torsi Giancarlo
Published: July 2003

The present work describes the analytical procedures for the voltammetric determination of Cu, Pb, Cd, Zn, Fe, Mn, Co, Ni, Sn, Sb and Bi in copper alloys. The possibility of determining simultaneously metal concentrations in the case of interference of the voltammetric signals due to the peak overlapping is also highlighted and discussed. The analytical procedure was verified by the analysis of the standard reference materials: commercial bronze A NIST-SRM 1115, gunmetal BCS-CRM 207/2, high tensile brass BCS-CRM 390. Precision and accuracy, expressed as relative standard deviation and relative error, respectively, were in all cases lower than 6%. The limits of detection for each element were also reported.
An Electrochemical Investigation of the Structure of Copper(II) Complexes of Schiff Base Ligands Derived from Salicylaldehyde and Substituted Anilines
Authors: Corsini Maddalena , Grigiotti Emanuela , Laschi Franco , Zanello Piero , Burgess John , Fawcett John , Gilani Syeda R.
Published: July 2003

An electrochemical investigation has been carried out on a series of Schiff base copper(II) complexes derived from salicylaldehyde and substituted anilines in the attempt to correlate the solid-state geometry of the CuN2O2 core, which is conditioned by the steric encumbrance of the different peripheral substituents, and the corresponding solution structures as inferred from either the distinctive features of the Cu(II)/Cu(I) reduction or the EPR characteristics of the original complexes. Even if a good agreement is expected between the extent of chemical reversibility of the reduction process and the tetrahedral distortion of the complexes, it has been found, that in reality, the chemical reversibility of the reduction process also holds for nominally planar complexes in that they are sufficient flexible to pass from planar to tetrahedral arrangements upon addition of one electron. The relative location of the Cu(II)/Cu(I) formal electrode potentials appears more pertinent in that the higher is the distortion the less negative is the potential value.
Poly(propylene amine) Dendrimers Decorated with Dimethoxybenzene Units. Photophysical and Electrochemical Properties
Authors: Ceroni Paola , Vicinelli Veronica , Maestri Mauro , Balzani Vincenzo , Gorka Marius , Lee Sang-Kyu , Dragut Patrick , Vögtle Fritz
Published: July 2003

We have investigated the absorption spectra, the fluorescence spectra and decay and the electrochemical redox processes of five dendrimers Gn (n = 1 to 5) that contain 2n+1 - 2 (i.e., 62 for G5) tertiary amino groups in the interior and 2n+1 (i.e., 64 for G5) 1,2-dimethoxybenzene (DMB) units in the periphery. In dichloromethane solution the absorption spectrum of the dendrimers is quite similar to that of 3,4-dimethoxy-N-propylbenzene-1- sulfonamide, a model compound of the peripheral DMB units. The fluorescence band of the DMB unit (λmax = 319 nm, τ = 0.95 ns, Φ = 0.08 for the model compound), however, is much weaker in the dendrimers, which also display a broad emission tail above 450 nm (τ from 2 to 7 ns, depending on dendrimer generation), assigned to exciplex formation between the peripheral dimethoxybenzene groups and the inner tertiary amino groups. Upon addition of trifluoroacetic acid, which causes protonation of the inner amino groups of the dendrimers, the intensity of exciplex emission decreases and the intensity of the 319 nm band of the DMB units increases, reaches a maximum, and then decreases with increasing protonation of the dendrimer interior, presumably because of excimer formation between peripheral DMB units. Electrochemical investigations have shown that in acetonitrile the dendrimers exhibit a reversible, multielectron oxidation wave at about +1.7 V vs SCE, assigned to the peripheral DMB units and broad anodic peaks in the region +0.8/+1.5 V, assigned to oxidation of the inner tertiary amino groups.
National physical education curriculum: motor and cardiovascular health related fitness in Greek adolescents
Authors: Koutedakis Y , Bouziotas C
Published: July 2003

Background:State school physical education (PE) programmes are common throughout Greece. However, it is not known if the main objectives of the Greek PE curriculum are achieved.

Objective:To assess the current national PE curriculum in relation to selected motor and cardiovascular health related fitness parameters.

Methods:A sample of 84 Greek schoolboys (mean (SD) age 13.6 (0.3) years, height 160.7 (8.6) cm, weight 50 (10.8) kg) volunteered. Forty three indicated participation only in school PE classes and habitual free play (PE group). The remaining 41 were involved in extracurricular organised physical activities in addition to school PE and habitual free play (PE+ group). The subjects underwent anthropometric, motor (flexibility, balance, standing broad jump, hand grip, sit ups, and plate tapping), and cardiovascular health related (percentage body fat, aerobic fitness, and physical activity) fitness assessments.

Results:Children in the PE group had inferior motor and cardiovascular health related fitness profiles compared with those in the PE+ group. Body fat (20.3 (8.8)v13.9 (3.5); p<0.001), aerobic fitness (34.7 (3.7)v43.9 (4.2); p<0.001), and time spent in intensive physical activity (0.2 (0.2)v0.7 (0.3); p<0.001) showed the greatest differences between the two groups. In the pupils in the PE group, these were lower than the levels proposed to be necessary to combat future health risks. Adjustments for confounding variables showed a decrease in the significance of motor fitness, but not in cardiovascular health related parameters.

Conclusions:The national PE curriculum for Greek secondary schools does not achieve the required levels of motor and cardiovascular health related fitness and should be reconsidered.
Decreased maximal aerobic capacity with use of a triphasic oral contraceptive in highly active women: a randomised controlled trial
Authors: Lebrun C M , Petit M A , McKenzie D C , Taunton J E , Prior J C
Published: July 2003

Background:Oral contraceptives are commonly used by women athletes. However, their effect on athletic performance is unclear.

Objectives:To examine the effects of a moderate dose, triphasic oral contraceptive on measures of athletic performance in highly trained women athletes.

Methods:This is a double blind, placebo controlled trial in 14 women with ovulatory menstrual cycles and maximal aerobic capacity (Vo2max) ≥50 ml/kg/min. Four measures of athletic performance were tested: Vo2max, anaerobic capacity (anaerobic speed test), aerobic endurance (time to fatigue at 90% of Vo2max), and isokinetic strength (Cybex II dynamometer). Height, weight, and six skinfold measurements were also recorded. All these observational tests were completed during both the follicular and mid-luteal phases of an ovulatory menstrual cycle. Cycle phases were confirmed by assaying plasma oestradiol and progesterone. Participants were subsequently randomly assigned to either a tricyclic oral contraceptive or placebo and retested in identical fashion (oral contraceptive phase).

Results:Absolute and relative changes in Vo2maxfrom follicular to oral contraceptive phase decreased in the oral contraceptive group by 4.7%, whereas the placebo group showed a slight increase (+1.5%) over the same time period. Two of the women taking oral contraceptive had decreases of 4 and 9 ml/kg/min. In contrast, most women in the placebo group improved or maintained Vo2max. There was also a significant increase in the sum of skinfolds in women taking oral contraceptive compared with those taking placebo (p<0.01). There were no significant changes in other physiological variables (maximum ventilation, heart rate, respiratory exchange ratio, packed cell volume) or measures of performance (anaerobic speed test, aerobic endurance, isokinetic strength) as a function of oral contraceptive treatment.

Conclusions:The decrease in Vo2maxthat occurs when oral contraceptive is taken may influence elite sporting performance in some women. Further studies are required to determine the mechanisms of this change.
Evaluation of cricket helmet performance and comparison with baseball and ice hockey helmets
Authors: McIntosh A S , Janda D
Published: July 2003

Background:Protective helmets in sport are important for reducing the risk of head and facial injury. In cricket and other sports with projectiles, national test standards control the minimum helmet performance. However, there are few field data showing if helmets are effective in reducing head injury.

Objectives:(a) To examine the performance of cricket helmets in laboratory tests; (b) to examine performance with regard to test standards, game hazards, and helmet construction; (c) to compare and contrast these findings with baseball and ice hockey helmets.

Methods:Impact tests were conducted on a selection of helmet models: five cricket, two baseball, and two ice hockey. Ball to helmet impacts at speeds of 19, 27, 36, and 45 m/s were produced using an air cannon and a Hybrid III dummy headform and neck unit. Free fall drop tests with a rigid headform on to a selection of anvils (flat rigid, flat deformable, and hemispherical rigid) were conducted. Resultant headform acceleration was measured and compared between tests.

Results:At the lower speed impacts, all helmets produced a good reduction in headform acceleration, and thus injury risk. At the higher speed impacts, the effectiveness was less. For example, the mean maximum headform accelerations for all cricket helmets at each speed were: 67, 160, 316, and 438gfor 19, 27, 36, and 45 m/s ball speeds respectively. Drop tests on to a hemispherical anvil produced the highest accelerations. The variation in performance increased as the magnitude of the impact energy increased, in both types of testing.

Conclusions:The test method used for baseball helmets in which the projectile is fired at the helmet may be superior to helmet drop tests. Cricket helmet performance is satisfactory for low speed impacts, but not for impacts at higher, more realistic, speeds. Baseball and ice hockey helmets offer slightly better relative and absolute performance at the 27 m/s ball and puck impacts.
Effect of testosterone and endurance training on glycogen metabolism in skeletal muscle of chronic hyperglycaemic female rats
Authors: van Breda E , Keizer H , Kuipers H , Kranenburg G
Published: July 2003

Objectives:To investigate in glycolytic and oxidative muscles of trained (nine weeks) and untrained hyperglycaemic female rats the effect of hyperandrogenicity and/or endurance training on energy metabolic properties.

Methods:Glycogen content and activity of muscle enzymes with regulatory functions in glycogen synthesis were examined.

Results:Testosterone treatment increased glycogen content of extensor digitorum longus (EDL) and soleus muscles of hyperglycaemic sedentary (18% and 84% respectively) and hyperglycaemic trained (7% and 16% respectively) rats. In both types of muscle of the hyperglycaemic testosterone treated exercised subgroup, less depletion of glycogen was found than in the untreated group (38% and 87% for EDL and soleus respectively).

Conclusions:The mechanisms by which training and/or hyperandrogenism alone or in combination elicits their specific effects are complex. Differences in sex, surgery, levels of hormones administered, and exercise model used may be the main reasons for the observed discrepancies. Conclusions from the results: (a) hyperandrogenism is not a primary cause of the development of insulin resistance; (b) glycogen content of slow and fast twitch muscle is increased by training through increased glycogen synthase activity. The most plausible explanation for differences between different muscle fibre types is the different levels of expression of androgen receptors in these fibres. Hyperandrogenicity therefore acts on energy metabolic variables of hyperglycaemic animals by different mechanisms in glycolytic and oxidative muscle fibres.
The Generation of GL(n, Z) by Finite State Automata
Authors: Brunner A. M. , Sidki Said
Published: July 2003

The linear group GL(n, Z) is residually finite by virtue of its action on the (one-rooted) regular 2n-ary coset tree for Zn. In this paper we construct finite state automata which effect this action. This shows that GL(n, Z) is embeddable in the group of finite state automorphisms of the one-rooted regular tree of valency 2n.
Time-Complexity of the Word Problem for Semigroups and the Higman Embedding Theorem
Authors: Birget Jean-Camille
Published: July 2003

The following algebraic characterization of the computational complexity of the word problem for finitely generated semigroups is proved, in the form of a refinement of the Higman Embedding Theorem:

Let S be a finitely generated semigroup whose word problem has nondeterministic time complexity T (where T is a function on the positive integers which is superadditive, i.e. T(n+m) ≥T(n)+T(m)). Then S can be embedded in a finitely presented semigroup H in which the derivation distance between any two equivalent words x and y (and hence the isoperimetric function) is O (T(∣x∣+∣y∣)2).

Moreover, there is a conjunctive linear-time reduction from the word problem of H to the word problem of S, so the word problems of S and H have the same nondeterministic time complexity (and also the same deterministic time complexity). Thus, a finitely generated semigroup S has a word problem in NTIME(T) (or in DTIME(To)) iff S is embeddable into a finitely presented semigroup H whose word problem is in NTIME(T) (respectively in DTIME(To)).

In the other direction, if a finitely generated semigroup S is embeddable in a finitely presented semigroup H with isoperimetric function ≤ D (where D(n) ≥ n), then the word problem of S has nondeterministic time complexity O(D).

The word problem of a finitely generated semigroup S is in NP (or more generally, in NTIME((T) O(1) )) iff S can be embedded in a finitely presented semigroup H with polynomial (respectively (T) O(1) ) isoperimetric function.

An algorithmic problem L is in NP (or more generally, in NTIME((T) O(1) )) iff L is reducible (via a linear-time one-to-one reduction) to the word problem of a finitely presented semigroup with polynomial (respectively (T) O(1) ) isoperimetric function.

In essence, this shows: (1) Finding embeddings into finitely presented semigroups or groups is an algebraic analogue of nondeterministic algorithm design; (2) the isoperimetric function is an algebraic analogue of nondeterministic time complexity.
Test Elements, Retracts and Automorphic Orbits of Free Algebras
Authors: Mikhalev Alexander A. , Yu Jie-Tai
Published: July 2003

A nonzero element a of an algebra A is called a test element if for any endomorphism φ of A it follows from φ(a)=a that φ is an automorphism of the algebra A. A subalgebra B of A is a retract if there is an ideal I of A such that A=B ⊕ I. We consider the main types of free algebras with the Nielsen–Schreier property: free nonassociative algebras, free commutative and anti-commutative nonassociative algebras, free Lie algebras and superalgebras, and free Lie p-algebras and p-superalgebras. For any free algebra F of finite rank of such type we prove that an element u is a test element if and only if it does not belong to any proper retract of F. Test elements for monomorphisms of F are exactly elements that are not contained in proper free factors of F. These results give analogs of Turner's results on test elements of free groups. We also characterize retracts of the algebra F. We prove that if some endomorphism φ preserve the automorphic orbit of some nonzero element of F, then φ is a monomorphism. For free Lie algebras and superalgebras over a field of characteristic zero and for free Lie p-(super)algebras over a field of prime characteristic p we show that in this situation φ is an automorphism. We discuss some related topics and formulate open problems.
A Cayley Theorem for Ternary Algebras
Authors: Ésik Z.
Published: July 2003

We prove a representation theorem of ternary algebras by ternary functions.
Linear Complexity of Some Generalized Cyclotomic Sequences
Authors: Ding Cunsheng
Published: July 2003

There are several kinds of cyclotomic sequences. They have a number of good random properties. In this paper we compute the linear complexity (linear span) of generalized cyclotomic binary sequences of order 2 with respect to p2.
On Groups Saturated with Abelian Subgroups
Authors: Kazarin Lev S. , Kurdachenko Leonid A. , Subbotin Igor Ya.
Published: July 2003

Groups with the weak maximal condition on non-abelian subgroups are the main subject of this research. Locally finite groups with this property are abelian or Chemikov. Non-abelian groups with the weak maximal condition on non-abelian subgroups, which have an ascending series of normal subgroups with locally nilpotent or locally finite factors, are described in this article.
Central Idempotents and Units in Rational Group Algebras of Alternating Groups
Authors: Giambruno A. , Jespers E.
Published: July 2003

Let ℚAn be the group algebra of the alternating group over the rationals. By exploiting the theory of Young tableaux, we give an explicit description of the minimal central idempotents of ℚAn. As an application we construct finitely many generators for a subgroup of finite index in the centre of the group of units of ℚAn.
The Relationship Between Two Commutators
Authors: Kearnes Keith A. , Szendrei Ágnes
Published: July 2003

We clarify the relationship between the linear commutator and the ordinary commutator by showing that in any variety satisfying a nontrivial idempotent Mal'cev condition the linear commutator is definable in terms of the centralizer relation. We derive from this that abelian algebras are quasi-affine in such varieties. We refine this by showing that if A is an abelian algebra and [Formula: see text](A) satisfies an idempotent Mal'cev condition which fails to hold in the variety of semilattices, then A is affine.
The Evaluation and the Computational Complexity of Datalog Queries of Boolean Constraint Databases
Authors: Revesz Peter Z.
Published: July 2003

In the database framework of Kanellakis et al. it was argued that constraint query languages should meet the closed-form requirement, that is, queries should take as input constraint databases and give as output constraint databases that use the same type of constraints. This paper shows that the closed-form requirement can be met for Datalog queries with Boolean equality constraints with double exponential time-complete data complexity, for Datalog queries with precedence and monotone inequality constraints in triple exponential-time data complexity. A closed-form evaluation is also shown for (Stratified) Datalog queries with equality and inequality constraints in atomless Boolean algebras in triple exponential-time data complexity.
Linear Equational Theories and Semimodule Representations
Authors: Ježek Jaroslav , Kepka Tomáš
Published: July 2003

Equational theories of some linear equations are studied. As a consequence, semimodule representations of the corresponding algebras are obtained. Examples are shown on medial and paramedial equations and some of their generalizations.
A Greatest Common Divisor Algorithm
Authors: Belenkiy Ari , Vidunas Raimundas
Published: July 2003

Algorithms of computation of the Greatest Common Divisor (GCD) of two integers play a principal role in all computational systems dealing with rational arithmetic. The simplest one (Euclidean) is not the best for large numbers (see D. E. Knuth's book "The Art of Computer Programming" for details).

One improvement was suggested by D. H. Lehmer in 1938 who noticed that it is possible to run the Euclidean algorithm with a few leading digits of large numbers and, with some care, still obtain the correct answer.

In the 70's G. E. Collins pointed out that Lehmer's algorithm simultaneously analyzed two similar sequences of numbers and hence did twice as much work as necessary. Collins found a way to work with only one sequence of numbers together with a verification of a certain inequality. The proof of the validity of this inequality is, perhaps, too complicated.

We present a similar but softer inequality and give a short and simple proof thereof.
Potential Divisibility in Finite Semigroups is Undecidable
Authors: Kublanovsky Stanislav , Sapir Mark
Published: July 2003

We prove that there is no algorithm to decide, given a finite semigroup S and two elements a, b∈S, whether there exists a bigger finite semigroup T>S where a divides b and b divides a. This solves a thirty years old problem by John Rhodes.
Standard Gröbner-Shirshov Bases of Free Algebras Over Rings, I
Authors: Mikhalev Alexander A. , Zolotykh Andrej A.
Published: July 2003

We consider standard bases of ideals of free associative algebras over rings. The main result of the article is a criterion for a subset of a free associative algebra to be a standard basis of the ideal it generates. Based on this result, we present an infinite algorithm to construct the reduced standard basis of an ideal. A generalization in case of some semigroup algebras is presented. We also describe a way to construct weak standard bases and reduced standard bases of ideals of a free associative algebra over an arbitrary finitely generated ring (over a finitely generated algebra over a field). Some examples of constructions of standard bases and of solutions of the equality problem are included.
A Study on ARQ Policies for Data Transmission based on Kullback–Leibler Information
Authors: Sawada Kiyoshi , Sandoh Hiroaki , Nakagawa Toshio
Published: July 2003

This study discusses methods for designing two types of ARQ policy; (1) the usual ARQ policy and (2) the extended ARQ policy, which is proposed in this study. In the protocol of the usual ARQ policy, the upper bound for the number of retransmissions of the data is empirically determined. A statistical model and a model based on Kullback–Leibler information (K–L model) are proposed for determining such a upper bound of retransmissions. Both the models are also applied to the extended ARQ policy. Numerical examples are presented to illustrate the K–L model which makes the design of ARQ policies easier than the statistical model.
Reliability Analysis with Sensitivity to Suspension Timings
Authors: Hastings Nicholas A. J. , Bartlett Harold J. G.
Published: July 2003

A two-stage method is presented for analysing reliability data with suspended items. The method proposed takes account of the ages of the suspended items when calculating plotting positions for the failure events. This sensitivity to suspension timings provides a more precise method than other plotting-based methods currently in use.
Availability and Reliability Information Administration System "ARIM-BL" by Methodology in "Inline-Online SQC"
Authors: Amasaka Kakuro , Sakai Hirohisa
Published: July 2003

This is a proposal for the implementation of "Science SQC" (a program based on the new scientific SQC method in Manufacturing) in order to elevate the quality of the business process. We construct the "Availability and Reliability Information Administration System — ARIM-BL" as a practical example of "Inline-Online SQC." As for the key technology of "Science SQC," it is indispensable to implement "Inline-Online SQC" by utilizing both methods consistently. It makes the dark points in business process clear and manages to communicate between man and information. This study describes the total integrated process information system, which links together between Production Engineering division and Manufacturing Engineering division. It is representative of intelligent "Inline-Online SQC." We have introduced the demonstrative and effective system into FBL (Flexible Body Line), which was the core of TPS (Toyota Production System).
Bayes Inference for Repairable Mechanical Units with Imperfect or Hazardous Maintenance
Authors: Calabria Raffaela , Pulcini Gianpaolo
Published: July 2003

The Modulated Power Law process (MPLP) has been recently proposed as a suitable model to describe the failure pattern of repairable mechanical units subject to imperfect or hazardous maintenance. In this paper, an informative Bayes procedure is proposed to analyze failure data arising from a MPLP sample, which allows prior information on the failure/repair process to be incorporated into the inferential procedure. Inference both of the MPLP parameters and of some functions thereof (such as the unconditional mean number of failures and the unconditional failure intensity), as well as prediction on failure times in a future sample, is developed. Finally, a numerical example is given to illustrate the proposed procedure.
Degradation Reliability Assessment Using Severe Critical Values
Authors: Yang Kai , Yang Guangbin
Published: July 2003

For some products that degrade over time, failure is defined in terms of a specified critical value of performance characteristic. The life of such a product depends on the specified critical value. The more severe the critical value, the shorter the life would be, and vice versa. This paper presents a method of accelerating life by using severe critical values. The method, based on degradation measurements, provides estimates of the relationship between life and critical value and reliability. An example is given to illustrate the application of the proposed method. Comparison between the method and traditional time-to-failure analysis shows that the proposed method is more efficient and cost-effective.
Alternatives of Taguchi's Approach for Dynamic Robust Design Problems
Authors: Tsui Kwok-Leung
Published: July 2003

Robust Design is an important method for improving product quality, manufacturability, and reliability at low cost. Most research in robust design has been focused on problems with static responses. This paper deals with the robust design problems with dynamic responses. The objective of the paper is to investigate and compare three modeling approaches: the loss model, the response function model, and the response model approaches. Taguchi16 proposes the loss model approach which models the loss measures as functions of the control factor effects. Miller and Wu10 propose the response function model approach which models the loss measures as functions of the effects of both control and noise factors. Tsui18 proposes the response model approach which directly models the response as a function of the effects of control, noise, and signal factors. In this paper, we identify and derive the relationships between the effect estimates of the three approaches and show that the loss model approach creates unnecessary biases for the factorial effect estimates and may lead to non-optimal solutions. The three modeling approaches are compared in a real example.
Monitoring Quality of Components by Fuzzy Control Principle
Authors: Lau Henry
Published: July 2003

A fuzzy expert system uses fuzzy logic control,1 which is based on a "superset" of Boolean logic that has been extended to handle the concept of "partial truth." It replaces mathematical models with models that are built from a number of rules with fuzzy variables such as output temperature, and fuzzy terms such as extremely hot, fairly cold. A fuzzy expert system has been implemented in a plastic moulding shop in Australia for monitoring dimensional quality of output products. Because these plastic parts are used as assembly components for production of gear boxes, their dimensional accuracy is of utmost importance. This paper presents the implementation of this monitoring system adopting a graphical and non-mathematical approach, and examines the application of fuzzy control systems in quality control. Practical examples with descriptions of how the fuzzy rules are shown and the operations of the fuzzy inference engine are covered.
Dynamic Response of Residuals of a Controlled Cutting Process to Shifts in the Process Mean
Authors: Yang Jiangbin , Makis Viliam
Published: July 2003

A usual approach to monitoring an autocorrelated process is to apply a control chart to the process residuals. In this paper, we study the statistical behavior of the residuals of a controlled second-order autoregressive (AR(2)) cutting process when a special-cause shift occurs to the process mean. Shewhart, exponentially weighted moving average (EWMA) and cumulative sum (CUSUM) control charts are applied to the residuals to monitor the cutting process. Formulas, integral equations and recursive procedures for computing the average run lengths (ARLs) of the charts are derived. Numerical results are presented and the relative performance of the charts is investigated.
A New Algorithm to Generate d-Minimal Paths in a Multistate Flow Network with Noninteger ARC Capacities
Authors: Lin Yi-Kuei , Yuan John
Published: July 2003

This article is mainly to study the reliability evaluation in terms of MPs (minimal paths) for a multistate flow network G in which the capacities of each arc are real numbers. The transportation system from the source node s to the sink node t is one of such typical networks. Given the system demand d from s to t and MPs in advance, an algorithm is proposed first to find out all lower boundary points of level d (namely d-MPs here). The system reliability which is the probability that the system flow satisfies the demand d can be calculated in terms of such d-MPs. One example is presented to illustrate how all its d-MPs are generated. The computational time complexity in the worst case and average cases for such an algorithm is presented.
A Note on Pseudodynamic Cost Limit Replacement Model
Authors: Choi Chung Hyeon , Yun Won Young
Published: July 2003

In this note, a pseudodynamic cost limit replacement policy presented by Park1 is considered. Park1 showed that the pseudodynamic policy is inferior to constant repair cost limit policy. In this note, the correct mean cost rate under the same assumption in the Park's model is obtained and the pseudodynamic policy is shown to be better than the constant repair cost limit policy2 through the same numerical examples of Park.1
Marginal Cost Analysis of Some Basic Ordering Policies for a Spare Unit and Extensions
Authors: Csenki Attila
Published: July 2003

The marginal cost approach has proved a useful economics-based alternative to the well known classical analysis of replacement models. In this paper, the marginal cost analysis' workings are explored for some basic ordering models for systems with a single spare unit. As with replacement models, the fundamental quantity of interest is the marginal cost function. While the basic pattern of analysis broadly corresponds to that for replacement models, the usual micro-type reasoning inherent in marginal cost analysis now has to be supplemented by some look-ahead considerations and a more detailed analysis. Moreover, the optimality equation derived here for ordering models is an extension of that for replacement models. Two kinds of objective functions are considered here: the long term expected cost rate function and the expected total discounted cost function. Several ordering policies are reviewed by way of the marginal cost approach, which, it is argued, is a viable and from the decision maker's perspective attractive tool of analysis also in the ordering context.
Process Capability Studies for Short Production Runs
Authors: Deleryd Mats , Vännman Kerstin
Published: July 2003

The current trend in modern production is directed towards shorter and shorter production runs. The two major reasons causing this trend are the rapid spread of the just in time (JIT) philosophy and the constantly increasing multiplicity of customer demands. The short runs of modern production not only constitute a challenge for production management, but they also cause some problems when applying traditional statistical methods, designed to be used for large sets of data. One of these methods is process capability studies. Since theories on how to use process capability studies in short production environments are incomplete, the aim of this paper is to present some ideas which will partly fill this gap.

The theories of process capability studies for short runs presented are based on ideas of focusing on the process, not on the products, and on using data transformation. By using the transformation presented, it is possible to conduct process capability studies in a traditional straightforward manner. A simulation study shows that the suggested transformation technique works satisfactorily in real situations. Finally, the [Formula: see text]-plot is introduced as a method of interpreting and analyzing the capability of a short run production process. By using the [Formula: see text]-plot, additional information is obtained concerning the capability of a process, compared to using traditional process capability indices only.
Single-Measurement Determination of a Complex Third-Order Susceptibility in Isotropic Media
Authors: Wiewiór P. , Radzewicz C. , Błȩdowski A. , Krasinski J. S.
Published: July 2003

A novel method for determination of real and imaginary parts of a third-order nonlinear susceptibility tensor in a single measurement is proposed and demonstrated. The method measures directly the ratio of imaginary to real part of the [Formula: see text] coefficient in isotropic media. Its sensitivity is high enough to enable measurements with unamplified pulses from a mode-locked Ti:Sapphire laser. Results of measurements for CS 2, 1-Chlornaphtalene and polycrystalline ZnSe are presented.
Spatially-Localized Band-Filling Effects and Band-Gap Renormalization in Growth-Interrupted Quantum Wells
Authors: Ding Yujie J. , Khurgin Jacob B.
Published: July 2003

We have observed a large excitonic linewidth broadening at low temperatures in growth-interrupted asymmetric-coupled quantum wells as irradiance increases. We attribute this broadening to the decrease of the exciton binding energy due to spatially-localized band-gap renormalization. We have also observed the stepwise saturation of the photoluminescence emission peaks as irradiance increases in growth-interrupted asymmetric-coupled quantum wells with various structures and doping profiles. We attribute this saturation to the result of spatially-localized band-filling effects. Based on the time-resolved photoluminescence measurements, we have determined the nature of the recombination processes and the exciton densities. In both undoped and modulation-doped samples, the small interface island area as a result of growth-interruption allows us to generate large carrier density in the islands; both band-gap renormalization and band-filling effects become stronger even at low irradiances. In compensation-doped asymmetric-coupled quantum wells, we observed anomalously large blue shift of donor-acceptor pair transition energy as the laser intensity increases.
Third-Order Optical Nonlinearity Due to Excitons and Biexcitons in a Self-Organized Quantum-Well Material (C6H13NH3)2PbI4
Authors: Ishi J. , Mizuno M. , Kunugita H. , Ema K. , Iwamoto S. , Hayase S. , Kondo T. , Ito R.
Published: July 2003

Third-order optical nonlinearity around the exciton resonance in (C6H13NH3)2PbI4 was measured using time-integrated and spectrally-resolved four-wave-mixing (FWM) techniques. For excitation below the exciton resonance, biexciton contribution to the FWM signals was observed. The dephasing energy of the biexcitons was estimated to be larger than 10 meV.
Ultrafast Excitonic Nonlinearity in Regioregular Head-to-Tail Coupled Poly(3-Hexylthiophene)
Authors: Ueno Yoshihiro , Kishino Shiho , Kunugita Hideyuki , Ema Kazuhiro , Rikukawa Masahiro , Tabuchi Yuko , Ogata Naoya
Published: July 2003

Third-order optical nonlinearity of regioregular head-to-tail coupled poly(3-hexylthiophene)(HT-PHT) was measured using degenerate four wave mixing (DFWM), and the dispersion spectrum of |χ(3)| around the exciton absorption peak was obtained. In addition, the relaxation process of the excitons was measured using the transient grating method. The resultant decay time was less than 2 ps and consisted of two components.
Generation of Non-Classical Light by Four-Wave Mixing in Semiconductors
Authors: Fox A. M. , Dabbicco M. , Ryan J. F.
Published: July 2003

We describe experiments to generate non-classical quadrature squeezed states of light by four-wave mixing in semiconductors. Squeezing can be achieved with either the diagonal or off-diagonal components of the third-order nonlinear susceptibility tensor. We have demonstrated squeezing by self-phase modulation in ZnS at 780 nm, and by cross-phase modulation in ZnSe at 960 nm. Possibilities for generating squeezed light in other materials by these techniques are discussed.
Coherent Exciton Dynamics in GaAs-Based Semiconductor Structures
Authors: Colocci M. , Bogani F. , Ceccherini S. , Gurioli M.
Published: July 2003

We show that a very powerful tool in the investigation of the coherent exciton dynamics in semiconductors is provided by the study of the emitted light after resonant excitation from pairs of phase-locked femtosecond pulses. Under these conditions, not only the full dynamics of the coherent transients (dephasing times, quantum beat periods, etc.) can be obtained from linear experiments, but it can also be obtained a straightforward discrimination between the coherent or incoherent character of the emission by means of spectral filtering.
Quantum Coherence in Ultrafast Semiconductor Spectroscopy
Authors: Haug Hartmut
Published: July 2003

Coherent optical phenomena such as the optical Stark effect, Rabi flopping, photon echo and quantum beating which are well-known in atomic spectroscopy can also be observed in semiconductors by using femtosecond laser pulses. On these short time scales, the quantum coherence of the optical excitations in the solid do not only influence the optical properties but change at the same time the relaxation and dephasing kinetics. The quasi-classical Boltzmann kinetics has to be replaced by quantum kinetics. Coherence leads to the appearance of memory in the scattering integrals. For femtosecond four-wave mixing and pump-and-probe spectroscopy the use of quantum kinetics for LO-phonon and for carrier-carrier scattering will be reviewed.
Detecting Phonon Vacuum Squeezing
Authors: Artoni M.
Published: July 2003

We examine quantum states of the atomic displacement which allow for the possibility of modulating its quantum fluctuations below the zero-point motion level. We address the issue of measuring such a squeezing of the phonon field and the framework for a suitable detection method is presented.
Nonlinear Optical Propagation in a Dye-Doped Nematic Liquid Crystal Waveguide
Authors: Abbate G. , de Stefano L.
Published: July 2003

A dye-doped nematic liquid crystal slab waveguide with an infinite homogeneous isotropic cladding is considered. The problem of light propagation in such a system is solved by a set of coupled nonlinear differential equations. This equation set is directly derived from the exact Maxwell's equations for the light and the torque balance equations for the medium response. The optical field amplitudes and the molecular director distributions are computed by means of a numerical technique based on the continuation method. The numerical results give evidence for a threshold effect, OFT-like. Above threshold, degeneration of modes and self-induced spatial splitting of the guided beam occur. Among the possible applications we propose a nonlinear switch for integrated optics.
Explicit Variational Solution of the Cubic-Quintic Nonlinear Schrödinger Equation for Pulse Propagation in Optical Fibers
Authors: Usman Adam , Osman Junaidah , Tilley D. R.
Published: July 2003

With a variational method, we study the cubic-quintic nonlinear Schrödinger equation for pulse propagation in optical fibers. Anomalous dispersion that gives rise to fundamental bright solitary waves is considered. It is shown that within the specified limits, the present variational model demonstrates (for 1 picosecond pulse) good agreements with its analytical equivalent. It is proved that for negative coefficient of the fifth-order nonlinearity existence of the two-state solitary wave solution is a peculiarity of the variational formulation.
Nonlinear Optics Generation from Nonlocal Response Functions with Surface Scattering in Simple Metals
Authors: Kao Chia Hung , Lue Juh Tzeng
Published: July 2003

In this work, the nonlocal nonlinear response fields in conjunction with two-dimensional Green's functions are implemented to solve the second harmonic generation (SHG) current density of a simple metal surface. By considering the surface boundary scattering of conduction electrons in metal films, we can fully elucidate the SHG without implying two phenomenological parameters a and b pertaining to the selvedge and bulk current sources as presented in the conventional hydrodynamic model.
Photoisomerization of Azo-Dyes in Nematic Liquid Crystals
Authors: Jánossy István , Szabados Lilla
Published: July 2003

The photoisomerization of azo dyes in nematic liquid crystals is investigated. Using a pump-probe technique, the absorption coefficients of the trans and cis isomers are evaluated separately and the dye order parameters of both forms are determined. It is shown that as a consequence of the difference of the trans and cis orientational order, the trans-cis equilibrium can be controlled through the polarization direction of the pump beam.
Absolute Measurements of the Second Order Susceptibilities of ZnSe, ZnTe and ZnS
Authors: Kühnelt M. , Wagner H. P.
Published: July 2003

The second order susceptibilities of single crystalline cubic ZnTe, ZnSe and ZnS have been determined using a Maker Oscillation technique. Q-switched Nd:YLF lasers emitting at fundamental wavelengths of λ F =1321 nm and λ F =1047 nm were used as light sources. The resulting second harmonic generation coefficients at λ F =1321 nm range from 8 pm/V (ZnS) to 52 pm/V (ZnTe). An increase of the values is observed at λ F =1047 nm as expected from the dispersion of the second order coefficients.
Measurement of the Nonlinear Coefficient of Carbon Disulfide using Holographic Self-Focusing
Authors: Widmayer C. Clay , Jones Laurel R. , Milam David
Published: July 2003

We report a measurement of the nonlinear refractive index coefficient, γ, of Carbon Disulfide ( CS 2), taken at a wavelength of 1.053 μm. The measurement uses a new technique based on the generation of high fluence holographic images of obscurations by self-focusing in the CS 2. Near-field beam distortion measurements are used in conjunction with detailed wave propagation analysis. The approach is attractive because it utilizes a sensitive near-field fluence measurement, it is tolerant of intensity modulation in the measurement beam, and it is straightforward to model with the computer. A value of γ = (3.1 ± 0.3)×10-14 cm2/W is obtained.
Nonlinear Optical Response of Poly(p-Phenylenevinylene)
Authors: Nampoothiri A. V. V. , Singh B. P. , Kumar G. Ravindra
Published: July 2003

Third order nonlinear optical properties of Poly(p-phenylenevinylene) have been investigated at 532 nm using degenerate four wave mixing and Z-scan techniques. Intensity dependent absorption has been attributed to photogenerated gap states arising from one-photon π–π* transition, and the coefficient of nonlinear absorption has been estimated. The observed intensity dependence of the degenerate four wave mixing signal has been explained using four-level model involving gap state transitions.
Assertive outreach teams in London: Models of operation
Authors: Wright Christine , Burns Tom , James Peter , Billings Joanne , Johnson Sonia , Muijen Matt , Priebe Stefan , Ryrie Iain , Watts Joanna , White Ian
Published: July 2003

Background

Assertive outreach teams have been introduced in the UK, based on the assertive community treatment (ACT) model. It is unclear how models of community care translate from one culture to another or the degree of adaptation that may result.

Aims

To characterise London assertive outreach teams and determine whether there are distinct groups within them.

Method

Semi-structured interviews with team managers plus one month's prospective process of care data collection were used to test for ‘model fidelity'to ACT and, by cluster analysis, to identify groupings.

Results

Fidelity varied widely, with four teams (out of 24 studied) rated ‘high fidelity’ and three teams rated ‘low fidelity’ by US standards and 17 rated ‘ACT-like’. Three clusters were identified, with voluntary sector teams being the most distinct group.

Conclusions

There is wide variation in the practice of assertive outreach in London. The role of the voluntary sector requires increased attention. Heterogeneity in practice is a clinical challenge but a research opportunity in distinguishing effective from redundant components of the approach.
Care Programme Approach – documentation of past risk-related behaviour
Authors: Dick Peter , Durham Tessa , Stewart Mitchell , Kane Scott , Duffy Jim
Published: July 2003

Aims and Method

The aim of the study was to assess the practicality of extracting past risk-related information from case records and to assess how this process might be cost-effectively incorporated in routine practice. Case records of 43 patients referred to the Care Programme Approach in Dundee were examined.

Results

Our study yielded relevant information – 39% of patients had a history of violence, 58% of self-harm or suicide, 58% of severe self-neglect and 72% of non-compliance with medication. However, it took an average of 5 hours to conduct a thorough review of each case because the notes were bulky and poorly organised.

Clinical Implications

Retrospective review of conventional case records in routine practice is likely to be incomplete and misleading. Prospective recording should be practicable if used selectively, but requires a standardised approach to clinical recording and case note maintenance. The risk recording system we developed, incorporating a dated index of incidents by risk category, followed by brief summaries of each incident, provides key clinical information not available from a simple check list while not sacrificing brevity.
Patient, client or service user? A survey of patient preferences of dress and address of six mental health professions
Authors: Mcguire-Snieckus Rebecca , Mccabe Rosemarie , Priebe Stefan
Published: July 2003

Aims and Method

A positive therapeutic relationship is essential to psychiatry and should take into account patients' preferences. Preferences of 133 community care patients were surveyed regarding dress and forms of address of six professions. Participants' sex, age, ethnicity and diagnosis were recorded.

Results

Ninety-eight per cent of participants expressed a preference. While most preferred to be called ‘patients' by general practitioners (75%) and psychiatrists (67%), there was no statistically significant difference in preference for the term ‘patient’ or ‘client’ when used by community psychiatric nurses, occupational therapists, psychologists or social workers. Participants over the age of 40 preferred the term ‘client’. Asymmetrical relationships were preferred with general practitioners and psychiatrists, evidenced by a preference to be addressed by first name (71% and 68%, respectively), to address the professional by title (81% and 80%, respectively), and the professional to be ‘smartly’ dressed (67% and 66%, respectively).

Clinical Implications

A more differentiated approach may be suggested by taking professional background and some demographic characteristics into consideration.