Proportional Topology Optimization: A new non-gradient method for solving stress constrained and minimum compliance problems and its implementation in MATLAB

A new topology optimization method called the Proportional Topology Optimization (PTO) is presented. As a non-gradient method, PTO is simple to understand, easy to implement, and is also efficient and accurate at the same time. It is implemented into two MATLAB programs to solve the stress constrained and minimum compliance problems. Descriptions of the algorithm and computer programs are provided in detail. The method is applied to solve three numerical examples for both types of problems. The method shows comparable efficiency and accuracy with an existing gradient optimality criteria method. Also, the PTO stress constrained algorithm and minimum compliance algorithm are compared by feeding output from one algorithm to the other in an alternative manner, where the former yields lower maximum stress and volume fraction but higher compliance compared to the latter. Advantages and disadvantages of the proposed method and future works are discussed. The computer programs are self-contained and publicly shared in the website www.ptomethod.org.Comment: 18 pages, 8 figures, and 2 appendices (MATLAB codes

Some determinants of path generating functions

We evaluate four families of determinants of matrices, where the entries are sums or differences of generating functions for paths consisting of up-steps, down-steps and level steps. By specialisation, these determinant evaluations have numerous corollaries. In particular, they cover numerous determinant evaluations of combinatorial numbers - most notably of Catalan, ballot, and of Motzkin numbers - that appeared previously in the literature.Comment: 35 pages, AmS-TeX; minor corrections; final version to appear in Adv. Appl. Mat

A slip model for micro/nano gas flows induced by body forces

A slip model for gas flows in micro/nano-channels induced by external body forces is derived based on Maxwell's collision theory between gas molecules and the wall. The model modifies the relationship between slip velocity and velocity gradient at the walls by introducing a new parameter in addition to the classic Tangential Momentum Accommodation Coefficient. Three-dimensional Molecular Dynamics simulations of helium gas flows under uniform body force field between copper flat walls with different channel height are used to validate the model and to determine this new parameter

Collaborative Development of Open Educational Resources for Open and Distance Learning

Open and distance learning (ODL) is mostly characterised by the up front development of self study educational resources that have to be paid for over time through use with larger student cohorts (typically in the hundreds per annum) than for conventional face to face classes. This different level of up front investment in educational resources, and increasing pressures to utilise more expensive formats such as rich media, means that collaborative development is necessary to firstly make use of diverse professional skills and secondly to defray these costs across institutions. The Open University (OU) has over 40 years of experience of using multi professional course teams to develop courses; of working with a wide range of other institutions to develop educational resources; and of licensing use of its educational resources to other HEIs. Many of these arrangements require formal contracts to work properly and clearly identify IPR and partner responsibilities. With the emergence of open educational resources (OER) through the use of open licences, the OU and other institutions has now been able to experiment with new ways of collaborating on the development of educational resources that are not so dependent on tight legal contracts because each partner is effectively granting rights to the others to use the educational resources they supply through the open licensing (Lane, 2011; Van Dorp and Lane, 2011). This set of case studies examines the many different collaborative models used for developing and using educational resources and explain how open licensing is making it easier to share the effort involved in developing educational resources between institutions as well as how it may enable new institutions to be able to start up open and distance learning programmes more easily and at less initial cost. Thus it looks at three initiatives involving people from the OU (namely TESSA, LECH-e, openED2.0) and contrasts these with the Peer-2-Peer University and the OER University as exemplars of how OER may change some of the fundamental features of open and distance learning in a Web 2.0 world. It concludes that while there may be multiple reasons and models for collaborating on the development of educational resources the very openness provided by the open licensing aligns both with general academic values and practice but also with well established principles of open innovation in businesses

Non-Metallic Inclusions in Carbon Steel Containing Rare Earth Metals

The effect of rare earth metals (RE) on composition of carbon steel and the quantity, size and morphologies of inclusions were experimentaly determined. Optical scann-ing electron microscopy and X-ray diffraction analysis as well as empirical calculations resulted that the RE affected the chemical composition of carbon steel and inclusions. The sulphur content did not vary. The inclu-sion quantity was increased. The RE modified inclusions, especially sulphides into small-smooth size under 4um. The steels containing from 0.01% to 0.02%RE have develo- ped globular oxysulphide inclusions of lb type, where as steels containing from 0.04% to 0.043% RE contain angular sulphide inclusions of Illb type. When the RE content in steel was over 0.062%RE harmful cluster sulphide inclu-sions of IV type was formed.Thus it was concluded that the RE beneficial affected the formation and modification of non-metallic inclusions in carbon steel

A Program Evaluation of an Apprenticeship Program using Stufflebeam’s CIPP Model

This dissertation is a program evaluation of an apprenticeship program operated by Siemens Energy, Inc. in Charlotte, North Carolina. The evaluation was based on Stufflebeam’s CIPP model of context (C), input (I), process (P), and product (P). The CIPP sought to evaluate (C) current and future objectives, (I) various strategies use to achieve the objectives, (P) the implementation of the strategies, and (P) the outcome of the program. The entire model provided insight into the effectiveness of the program and provided feedback for decision making and accountability toward current and future improvement of the program (Stufflebeam, 1971). Four questions were cultivated to align with the CIPP model. The four CIPP questions were (a) Context: How are the objectives of the program matched up with the needs of Siemens and the apprentices; (b) Input: What characteristics help apprentices finish their program? (c) Process: Are the apprentices being successfully trained; and (d) Product: What was the outcome in meeting the program’s strategic plan? The research design methodology follows several pathways. Current apprentices took the online survey of the Noel-Levitz Adult Learner Inventory. They also completed the apprentice survey and were involved in a planned interview. The management team was administered a survey and was part of an interview. Other documents and data were reviewed and analyzed such as strategic plans, current and projected sales demand, applicant and apprentice information, training materials, graduation, retention, and employment information. Based on the findings of the program evaluation, the apprenticeship program is effective and accomplishing its goals. The researcher has concluded three recommendations for consideration based on the evaluation findings: provide more support for apprentices, ensure the apprentices fully comprehend the curriculum requirements and expectations for their associate’s degree, and develop a strategic plan with a mission and vision statement

Myrtaceae, a cache of fungal biodiversity

Twenty-six species of microfungi are treated, the majority of which are associated with leaf spots of Corymbia, Eucalyptus and Syzygium spp. (Myrtaceae). The treated species include three new genera, Bagadiella, Foliocryphia and Pseudoramichloridium, 20 new species and one new combination. Novelties on Eucalyptus include: Antennariella placitae, Bagadiella lunata, Cladoriella rubrigena, C. paleospora, Cyphellophora eucalypti, Elsinoë eucalypticola, Foliocryphia eucalypti, Leptoxyphium madagascariense, Neofabraea eucalypti, Polyscytalum algarvense, Quambalaria simpsonii, Selenophoma australiensis, Sphaceloma tectificae, Strelitziana australiensis and Zeloasperisporium eucalyptorum. Stylaspergillus synanamorphs are reported for two species of Parasympodiella, P. eucalypti sp. nov. and P. elongata, while Blastacervulus eucalypti, Minimedusa obcoronata and Sydowia eucalypti are described from culture. Furthermore, Penidiella corymbia and Pseudoramichloridium henryi are newly described on Corymbia, Pseudocercospora palleobrunnea on Syzygium and Rachicladosporium americanum on leaf litter. To facilitate species identification, as well as determine phylogenetic relationships, DNA sequence data were generated from the internal transcribed spacers (ITS1, 5.8S nrDNA, ITS2) and the 28S nrDNA (LSU) regions of all taxa studie

Verification of a localization criterion for several disordered media

We analytically compute a localization criterion in double scattering approximation for a set of dielectric spheres or perfectly conducting disks uniformly distributed in a spatial volume which can be either spherical or layered. For every disordered medium, we numerically investigate a localization criterion, and examine the influence of the system parameters on the wavelength localization domains.Comment: 30 pages, LateX, amstex, revtex styles, 20 figure