A probabilistic approach to the problem of electron localization in disordered systems and sharpness of the mobility edge

By applying the theory of the asymptotic distribution of extremes and a certain stability criterion to the question of the domain of convergence in the probability sense, of the renormalized perturbation expansion (RPE) for the site self-energy in a cellularly disordered system, an expression has been obtained in closed form for the probability of nonconvergence of the RPE on the real-energy axis. Hence, the intrinsic mobility mu (E) as a function of the carrier energy E is deduced to be given by mu (E)= mu 0exp(-exp( mod E mod -Ec) Delta ), where Ec is a nominal 'mobility edge' and Delta is the width of the random site-energy distribution. Thus mobility falls off sharply but continuously for mod E mod >Ec, in contradistinction with the notion of an abrupt 'mobility edge' proposed by Cohen et al. and Mott. Also, the calculated electrical conductivity shows a temperature dependence in qualitative agreement with experiments on disordered semiconductors.

X-ray absorption spectroscopic study of the mixed valence system CePd3

Mixed valency in CePd3 has been examined by a study of the LIII (Ce) absorption edge in this compound as well as other model compounds. In CePd3, peaks characteristic of 3+ and 4+ states of Ce are found to be separated by 2 eV.

An inhomogeneity problem in couple stress theory

Using Hilbert theory and Mindlin's couple stress theory, the problem of two-dimensional circular inhomogeneity (when the inserted material is of different size than the size of the cavity and having different elastic constants) is studiedin this paper. Stress could be bounded at infinity. The formulation is valid also for regions other then the circular ones when the matrix is finite has also been tackled. Numerical results are in conformity with the fact that the effect of couple stresses is negligible when the ratio of the smallest dimension of the body to the cahracteristic length is large.

On the orthogonality of suboptimum estimate in the combined estimation and control problem

By deriving the equations for an error analysis of modeling inaccuracies for the combined estimation and control problem, it is shown that the optimum estimation error is orthogonal to the actual suboptimum estimate.

A problem in micropolar elasticity

In this paper a three-dimensional analysis for statics and dynamics of a class of simply supported rectangular plates made up of micropolar elastic material is presented. The solution is in the form of series, in which each term is explicitly determined. For free vibrations, the frequencies are obtained by the solution of a closed form characteristic equation.

4QMMT - The Problem of the Epilogue

The main focus of this study is the epilogue of 4QMMT (4QMiqsat Ma aseh ha-Torah), a text of obscure genre containing a halakhic section found in cave 4 at Qumran. In the official edition published in the series Discoveries of the Judaean Desert (DJD X), the extant document was divided by its editors, Elisha Qimron and John Strugnell, into three literary divisions: Section A) the calendar section representing a 364-day solar calendar, Section B) the halakhot, and Section C) an epilogue. The work begins with text critical inspection of the manuscripts containing text from the epilogue (mss 4Q397, 4Q398, and 4Q399). However, since the relationship of the epilogue to the other sections of the whole document 4QMMT is under investigation, the calendrical fragments (4Q327 and 4Q394 3-7, lines 1-3) and the halakhic section also receive some attention, albeit more limited and purpose oriented. In Ch. 2, after a transcription of the fragments of the epilogue, a synopsis is presented in order to evaluate the composite text of the DJD X edition in light of the evidence provided by the individual manuscripts. As a result, several critical comments are offered, and finally, an alternative arrangement of the fragments of the epilogue with an English translation. In the following chapter (Ch. 3), the diversity of the two main literary divisions, the halakhic section and the epilogue, is discussed, and it is demonstrated that the author(s) of 4QMMT adopted and adjusted the covenantal pattern known from biblical law collections, more specifically Deuteronomy. The question of the genre of 4QMMT is investigated in Ch. 4. The final chapter (Ch. 5) contains an analysis of the use of Scripture in the epilogue. In a close reading, both the explicit citations and the more subtle allusions are investigated in an attempt to trace the theology of the epilogue. The main emphases of the epilogue are covenantal faithfulness, repentance and return. The contents of the document reflect a grave concern for the purity of the cult in Jerusalem, and in the epilogue Deuteronomic language and expressions are used to convince the readers of the necessity of a reformation. The large number of late copies found in cave 4 at Qumran witness the significance of 4QMMT and the continuous importance of the Jerusalem Temple for the Qumran community.

A new multi-objective model to optimise rail transport scheduler

The sugarcane transport system plays a critical role in the overall performance of Australia’s sugarcane industry. An inefficient sugarcane transport system interrupts the raw sugarcane harvesting process, delays the delivery of sugarcane to the mill, deteriorates the sugar quality, increases the usage of empty bins, and leads to the additional sugarcane production costs. Due to these negative effects, there is an urgent need for an efficient sugarcane transport schedule that should be developed by the rail schedulers. In this study, a multi-objective model using mixed integer programming (MIP) is developed to produce an industry-oriented scheduling optimiser for sugarcane rail transport system. The exact MIP solver (IBM ILOG-CPLEX) is applied to minimise the makespan and the total operating time as multi-objective functions. Moreover, the so-called Siding neighbourhood search (SNS) algorithm is developed and integrated with Sidings Satisfaction Priorities (SSP) and Rail Conflict Elimination (RCE) algorithms to solve the problem in a more efficient way. In implementation, the sugarcane transport system of Kalamia Sugar Mill that is a coastal locality about 1050 km northwest of Brisbane city is investigated as a real case study. Computational experiments indicate that high-quality solutions are obtainable in industry-scale applications.

On the orthogonality of suboptimum estimate in the combined estimation and control problem

By deriving the equations for an error analysis of modeling inaccuracies for the combined estimation and control problem, it is shown that the optimum estimation error is orthogonal to the actual suboptimum estimate.

Application of the Conjugate Gradient Method to a Problem on Minimum Time Orbit Transfer

This correspondence considers the problem of optimally controlling the thrust steering angle of an ion-propelled spaceship so as to effect a minimum time coplanar orbit transfer from the mean orbital distance of Earth to mean Martian and Venusian orbital distances. This problem has been modelled as a free terminal time-optimal control problem with unbounded control variable and with state variable equality constraints at the final time. The problem has been solved by the penalty function approach, using the conjugate gradient algorithm. In general, the optimal solution shows a significant departure from earlier work. In particular, the optimal control in the case of Earth-Mars orbit transfer, during the initial phase of the spaceship's flight, is found to be negative, resulting in the motion of the spaceship within the Earth's orbit for a significant fraction of the total optimized orbit transfer time. Such a feature exhibited by the optimal solution has not been reported at all by earlier investigators of this problem.

Rethinking connectedness : an investigation into the access of teacher professional learning in regional and remote Western Australia

Many teachers working in remote and regional areas have limited access to collegial support networks. This research aimed to examine the existing strategies that were being undertaken by the Department of Education in Western Australia, to provide professional learning to teachers in regional and remote areas. It was important to establish the perceptions of teachers’ access to professional learning from those working at the coalface in geographically dispersed areas. Consequently, the possible opportunity for improving the amount and variety of professional learning, through the application of both synchronous and asynchronous technologies was proposed. The study was guided by the primary research question: “In what ways might technology be used to support professional development of regional and remote teachers in Western Australia?” Generating descriptions of current practice of professional learning along with the teacher perceptions were central to this research endeavour. The study relied on a mixed method research approach in order to attend to the research question. The data were collected in phases, referred to as an explanatory mixed methods design. Quantitative data were collected from 104 participants to provide a general picture of the research problem. To further refine this general picture, qualitative data were collected through interviews and e-interviews of 10 teachers. Participants in the study included graduate teachers, teachers who had taught more than two years, senior teachers and Level Three teachers from seven teaching districts within Western Australia. An investigation into current practice was included in this phase and technologies available to support a professional learning community over distance were documented. The final phase incorporated the formulation of a conceptual framework where a model was developed to facilitate the successful implementation of a professional learning community through the application of synchronous and asynchronous technologies. The study has identified that travel time in order to access professional development is significant and impacts on teachers’ personal time. There are limited relief teachers available in these isolated areas which impacts on the opportunities to access professional development. Teachers face inequities, in terms of promotion, because professional development is explicitly linked to promotional opportunities. Importantly, it was found that professional learning communities are valued, but are often limited by small staff numbers at the geographic locality of the school. Teachers preferred to undertake professional learning in the local context of their district, school or classroom and this professional learning must be established at the need of the individual teacher in line with the school priorities. Teachers reported they were confident in using technology and accessing professional development online if required, however, much uncertainty surrounded the use of web 2.0 technologies for this purpose. The recommendations made from the study are intended to identify how a professional learning community might be enhanced through synchronous and asynchronous technologies.

The problem of liquid droplet combustion-reexamination

The simple quasi-steady analysis of the combustion of a liquid fuel droplet in an oxidising atmosphere provides unsatisfactory explanations for several experimental observations. It's prediction of values for the burning constant (K), the flame-to-droplet diameter ratio ( ) and the flame temperature (Tf) have been found to be amgibuous if not completely inaccurate. A critical survey of the literature has led us to a detailed examination of the effects of unsteadiness and variable properties. The work published to date indicates that the gas-phase unsteadiness is relatively short and therefore quite insignificant.A new theoretical analysis based on heat transfer within the droplet is presented here. It shows that the condensed-phase unsteadiness lasts for about 20â??25% of the total burning time. It is concluded that the discrepancies between experimental observations and the predictions of the constant-property quasi-steady analysis cannot be attributed either to gas-phase or condensed-phase unsteadiness.An analytical model of quasi-steady droplet combustion with variable thermodynamic and transport properties and non-unity Lewis numbers will be examined. Further findings reveal a significant improvement in the prediction of combustion parameters, particularly of K, when consideration is given to variations of cp and λ with the temperature and concentrations of several species. Tf is accurately predicted when the required conditions of incomplete combustion or low ( ) at the flame are met. Further refinement through realistic Lewis numbers predicts ( ) meaningfully.

An operational-level multi-stage mine production timetabling model for optimally synchronising drilling, blasting and excavating operations

This paper proposes a new multi-stage mine production timetabling (MMPT) model to optimise open-pit mine production operations including drilling, blasting and excavating under real-time mining constraints. The MMPT problem is formulated as a mixed integer programming model and can be optimally solved for small-size MMPT instances by IBM ILOG-CPLEX. Due to NP-hardness, an improved shifting-bottleneck-procedure algorithm based on the extended disjunctive graph is developed to solve large-size MMPT instances in an effective and efficient way. Extensive computational experiments are presented to validate the proposed algorithm that is able to efficiently obtain the near-optimal operational timetable of mining equipment units. The advantages are indicated by sensitivity analysis under various real-life scenarios. The proposed MMPT methodology is promising to be implemented as a tool for mining industry because it is straightforwardly modelled as a standard scheduling model, efficiently solved by the heuristic algorithm, and flexibly expanded by adopting additional industrial constraints.

On trade-off solution pairs in a special type of transportation problem

Abstract is not available.

Mixed reality stories: How creative writers integrate virtual and physical realities

Mixed reality stories (MRS) unfold simultaneously in the physical and the virtual world. Advancements in digital technologies, which are now able to capture more contextual information about our physical environments, are enabling novel ways of blending the two worlds. To explore the process of creating stories from this perspective, we conducted a study with creative writers, in which we asked them to write a MRS script for outdoor running. While we saw instances of intentional connections between physical and virtual worlds in their work, we also observed the use of ambiguity or even deliberate contradiction with available contextual information. In this paper we discuss how these approaches can be beneficial for MRS and propose directions for future work.