A GA-based technique for the scheduling of storage tanks

YesThis paper proposes the application of a genetic algorithm based methodology for the scheduling of storage tanks. The proposed approach is an integration of GA and heuristic rule-based techniques, which decomposes the complex mixed integer optimisation problem into integer and real number subproblems. The GA string considers the integer problem, and the heuristic approach solves the real number problems within the GA framework. The algorithm is demonstrated for a test problem related to a water treatment facility at a port, and has been found to give a significantly better schedule than those generated using a heuristic-based approach

Genetic algorithms for scheduling generation and maintenance in power systems

N

Noise-enabled precision measurements of a Duffing nanomechanical resonator

We report quantitative experimental measurements of the nonlinear response of a radiofrequency mechanical resonator, with very high quality factor, driven by a large swept-frequency force. We directly measure the noise-free transition dynamics between the two basins of attraction that appear in the nonlinear regime, and find good agreement with those predicted by the one-dimensional Duffing equation of motion. We then measure the response of the transition rates to controlled levels of white noise, and extract the activation energy from each basin. The measurements of the noise-induced transitions allow us to obtain precise values for the critical frequencies, the natural resonance frequency, and the cubic nonlinear parameter in the Duffing oscillator, with direct applications to high sensitivity parametric sensors based on these resonators.Comment: 5 pages, 5 figure

Large-Scale Integration of Nanoelectromechanical Systems for Gas Sensing Applications

We have developed arrays of nanomechanical systems (NEMS) by large-scale integration, comprising thousands of individual nanoresonators with densities of up to 6 million NEMS per square centimeter. The individual NEMS devices are electrically coupled using a combined series-parallel configuration that is extremely robust with respect to lithographical defects and mechanical or electrostatic-discharge damage. Given the large number of connected nanoresonators, the arrays are able to handle extremely high input powers (>1 W per array, corresponding to <1 mW per nanoresonator) without excessive heating or deterioration of resonance response. We demonstrate the utility of integrated NEMS arrays as high-performance chemical vapor sensors, detecting a part-per-billion concentration of a chemical warfare simulant within only a 2 s exposure period

Time - Dependency of chloride diffusion in concrete: a brief review and preliminary results

AbstractChloride ingress into concrete has long been known to decrease the service life of built infrastructure. Inadequate knowledge of the physical reasons associated with chloride diffusion into concrete could generate chloride penetration profiles that become meaningless for prediction of service life. In this study, the effects of pore closure (physical effect) and changes in chloride binding (chemical effect) on chloride diffusion through Australian General Purpose (GP) cement pastes were investigated. Through - diffusion tests and &ldquo;in - and - out&rdquo; diffusion tests were conducted to monitor the time - dependent chloride diffusion through cement pastes cured from 1 to 28 days. The through - diffusion test quantified the overall chloride diffusion behaviour at different stages of cement hydration, which was a combined result of physical and chemical processes controlling diffusion. The &ldquo;in - and - out&rdquo; test differentiated the contributions of the physical and chemical processes on the chloride diffusion at different stages of cement hydration. As expected, the reduction of chloride diffusivity was significant during the first two weeks of curing, most likely attributed to the significant reduction of porosity as well as establishment of capillary discontinuities within the pore structure. It was also observed that the amount of bound chloride was not constant but increased significantly from 1 to 28 days of curing age. <br /

Using teacher action research to promote constructivist learning environments in South Africa

The primary focus was to assist South African teachers to become reflective practitioners in their daily mathematics classroom teaching. The study involved a combination of quantitative and qualitative research methods. Quantitative data were collected using the Constructivist Learning Environment Survey (CLES) to assess learners' perceptions of the emphasis on constructivism in the classroom environment. In the first phase of the study, the CLES was administered to 1 864 learners in 43 classes and analysed to determine whether the CLES is valid and reliable for use in South Africa. As well, descriptive analysis was used to generate graphical profiles of learners' perceptions of the actual and preferred learning environment for each class. During the second 12-week intervention phase, two teachers used the profiles to assist them to develop strategies aimed at improving the constructivist orientation of their classroom learning environments. The teachers implemented strategies and maintained a daily journal as a means of reflecting on their teaching practices. At the end of the 12 weeks, the CLES was re-administered to learners to determine whether their learners' perceptions of the constructivist emphasis in their classroom learning environments had changed. South African Journal of Education Vol.24(4) 2004: 245-25

A study of the ontogeny of the molar dentition of some microchiroptera with special reference to the development of occlusal

The functioning of the molar teeth depends upon a correct relationship between the cusps of the two jaws. This is perhaps less evident in man owing to the flatness of the molar crowns; accordingly, an animal with pointed, interlocking cusps was studied - the insectivous bat Hipposideros beatus. The purpose of the work was to find the growth processes involved to ensure a correct mutual positioning of the erupted teeth in an animal where normal occlusion is essential. So that with a knowledge of normal occlusion, factors causing malocclusion may be better understood. Graphic and wax-plate reconstructions were made of the teeth and jaws in a series of H. beatus embryos. The methods of reconstructing this difficult material are described in Chapter II. In Chapter III the adult dentition and the occlusal relations of the teeth are described. The latter aided by a slow-motion cinematograph study of the chewing action in a British bat. Chapter IV is concerned with the growth and calcification of the tooth germs. Chapter V is concerned with the movements of the tooth germs during ontogeny. In both these chapters the growth of the upper toothrow is compared with the growth of the lower toothrow. It is found that the intrinsic growth of the tooth germs is such, that at all stages, models of teeth, that will later occlude, will fit if put together. However the teeth do not occupy their correct positions relative to each other until eruption. To attain these positions complicated growth movements take place. These movements, and a possible explanation for them are described. Eruption appears to be the terminal phase of these growth movements. The results of the investigation are discussed in Chapter VI.<p

Code sets for respiratory symptoms in electronic health records (EHR) research: a systematic review protocol

Introduction Asthma and chronic obstructive pulmonary disease (COPD) are common respiratory conditions, which result in significant morbidity worldwide. These conditions are associated with a range of non-specific symptoms, which in themselves are a target for health research. Such research is increasingly being conducted using electronic health records (EHRs), but computable phenotype definitions, in the form of code sets or code lists, are required to extract structured data from these large routine databases in a systematic and reproducible way. The aim of this protocol is to specify a systematic review to identify code sets for respiratory symptoms in EHRs research. Methods and analysis MEDLINE and Embase databases will be searched using terms relating to EHRs, respiratory symptoms and use of code sets. The search will cover all English-language studies in these databases between January 1990 and December 2017. Two reviewers will independently screen identified studies for inclusion, and key data will be extracted into a uniform table, facilitating cross-comparison of codes used. Disagreements between the reviewers will be adjudicated by a third reviewer. This protocol has been produced in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocol guidelines. Ethics and dissemination As a review of previously published studies, no ethical approval is required. The results of this review will be submitted to a peer-reviewed journal for publication and can be used in future research into respiratory symptoms that uses electronic healthcare databases