Some Stability Results for Markovian Economic Semigroups

The paper studies existence, uniqueness and stability of stationary equilibrium distributions in a class of stochastic dynamic models common to economic analysis. The stability conditions provided are suitable for treating multi-sector models and nonlinear time series models with unbounded state.Markov processes, asymptotic stability, semigroups

Test results of a Stirling engine utilizing heat exchanger modules with an integral heat pipe

The Heat Pipe Stirling Engine (HP-1000), a free-piston Stirling engine incorporating three heat exchanger modules, each having a sodium filled heat pipe, has been tested at the NASA-Lewis Research Center as part of the Civil Space Technology Initiative (CSTI). The heat exchanger modules were designed to reduce the number of potential flow leak paths in the heat exchanger assembly and incorporate a heat pipe as the link between the heat source and the engine. An existing RE-1000 free-piston Stirling engine was modified to operate using the heat exchanger modules. This paper describes heat exchanger module and engine performance during baseline testing. Condenser temperature profiles, brake power, and efficiency are presented and discussed

SCORE: A Second-Order Conic Initialization for Range-Aided SLAM

We present a novel initialization technique for the range-aided simultaneous localization and mapping (RA-SLAM) problem. In RA-SLAM we consider measurements of point-to-point distances in addition to measurements of rigid transformations to landmark or pose variables. Standard formulations of RA-SLAM approach the problem as non-convex optimization, which requires a good initialization to obtain quality results. The initialization technique proposed here relaxes the RA-SLAM problem to a convex problem which is then solved to determine an initialization for the original, non-convex problem. The relaxation is a second-order cone program (SOCP), which is derived from a quadratically constrained quadratic program (QCQP) formulation of the RA-SLAM problem. As a SOCP, the method is highly scalable. We name this relaxation Second-order COnic RElaxation for RA-SLAM (SCORE). To our knowledge, this work represents the first convex relaxation for RA-SLAM. We present real-world and simulated experiments which show SCORE initialization permits the efficient recovery of quality solutions for a variety of challenging single- and multi-robot RA-SLAM problems with thousands of poses and range measurements.Comment: 9 pages, 8 figures, extended version of paper submitted to ICRA 202

Mahasiswa Diseru Terokai Bidang Keusahawanan

USM KUBANG KERIAN, 11 Mac 2018 – “Mahasiswa yang masih lagi melanjutkan pelajaran di Institusi Pengajian Tinggi (IPT) digalakkan menceburi bidang keusahawanan walaupun masih bergelar pelajar”, demikian perkongsian Pengerusi Koperasi Ko-Ummah yang juga Alumni Universiti Sains Malaysia (USM), Luqman Nurhakim Perma Suria

Nano-Size Layered Manganese-Calcium Oxide as an Efficient and Biomimetic Catalyst for Water Oxidation Under Acidic Conditions: Comparable To Platinum

Inspired by Nature's catalyst, a nano-size layered manganese-calcium oxide showed a low overvoltage for water oxidation in acidic solutions, which is comparable to platinum.Institute for Advanced Studies in Basic Sciences and the National Elite FoundationUS Department of Energy, Office of Basic Energy Sciences, Division of Chemical, Geochemical and Biological Sciences DE-FG02-86ER13622, DE-FG0209ER16119Russian Foundation for Basic Research 11-04-01389a, 12-0492101a, 13-04-92711aMolecular and Cell Biology Programs of the Russian Academy of SciencesCenter for Electrochemistr

Determination of the predictive factors of long-lasting insecticide-treated net ownership and utilisation in the Bamenda Health District of Cameroon

Abstract Background Malaria is a serious health concern in Africa. In Cameroon, an endemic country where malaria remains a major public health problem, several control measures have been put in place among which the use of insecticide-treated bednets (LLINs/ITNs) is considered one of the core vector control strategies. However, the greatest challenges include ownership and utilisation by individuals and households. Factors such as age, marital status, gender, education and occupation of the household head, household size, knowledge of bednets, socioeconomic status, and environmental factors have been suggested to have an impact on bednet ownership and utilisation in different settings. The present study sought to determine bednet ownership and utilisation rates and to assess the impact of predictive factors on bednet ownership and use in the Bamenda Health District (BHD) of Cameroon. Methods A cross-sectional study involving 384 households was conducted in six health areas in the BHD. A structured and semi-structured questionnaire was used to collect data on demographic and household characteristics as well as information on their bednet ownership and utilisation. Descriptive statistics, bivariate and multivariate logistic regression analysis were performed. Results Frequency of bednet ownership was relatively high (63.5%) with LLINs being most abundant (91.9%); the majority of households (87.7%) obtained their bednets during the 2011 free distribution campaign. Utilisation was relatively high (69.3%), with negligence (29.3%) and heat discomfort (26.7%) accounting most for non-usage of bednets. Children less than 5 years (63%) and pregnant women (60%) most often used these nets. Households headed by a married couple, those with older household heads, household with smaller size (5–12 persons), and knowledge of bednets (good knowledge) had positive impacts on bednet ownership (p < 0.05). The gender of the household head (males), their educational level, environmental conditions (presence of suitable mosquito breeding sites), bednet number in households (greater number of bednets) and the prioritised groups (children < 5 and pregnant women) had positive impacts on bednet utilisation in households (p < 0.05). There was a negative association between bednet ownership and utilisation by households as bednet ownership was high and utilisation of these nets was low. Marital status and age of household head, household size, and knowledge of bednets had impacts on bednet ownership while gender and educational level of the household head, environmental suitability, the number of bednets and the two prioritised groups had an impact on bednet usage. Conclusion These factors may be relevant for policy makers and in decision making for the intensification of campaign strategies to ensure more effective subsequent distribution campaigns in the BHD and beyond

Nanoscale Intelligent Imaging Based on Real-Time Analysis of Approach Curve by Scanning Electrochemical Microscopy

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Analytical Chemistry, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acs.analchem.9b02361.Scanning electrochemical microscopy (SECM) enables high-resolution imaging by examining the amperometric response of an ultramicroelectrode tip near a substrate. Spatial resolution, however, is compromised for non-flat substrates, where distances from a tip far exceed the tip size to avoid artifacts caused by the tip–substrate contact. Herein, we propose a new imaging mode of SECM based on real-time analysis of approach curve to actively control nanoscale tip–substrate distances without contact. The power of this software-based method is demonstrated by imaging an insulating substrate with step edges using standard instrumentation without combination of another method for distance measurement, e.g., atomic force microscopy. An ~500 nm-diameter Pt tip approaches down to ~50 nm from upper and lower terraces of a 500 nm-height step edge, which are located by real-time theoretical fitting of experimental approach curve to ensure the lack of electrochemical reactivity. The tip approach to step edge can be terminated at <20 nm prior to the tip–substrate contact as soon as the theory deviates from the tip current, which is analyzed numerically afterward to locate the inert edge. The advantageous local adjustment of tip height and tip current at the final point of tip approach distinguishes the proposed imaging mode from other modes based on standard instrumentation. In addition, the glass sheath of Pt tip is thinned to ~150 nm to rarely contact the step edge, which is unavoidable and instantaneously detected as an abrupt change in the slope of approach curve to prevent the damage of fragile nanotip