148 research outputs found

    Adsorption Properties of Malaysian Activated Carbon for Use in Solar Refrigerator

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    Detail experiments and analyses have been made on the solar refrigerator using activated charcoal and methanol adsorption cycle. A test rig was designed to study adsorption and desorption capability of activated carbon. A comparison has been made between adsorbability of six Malaysian commercial activated carbons. To improve the adsorbability of the carbon a simple method was tested. Base on Dubinin equation, some them10dynamic properties of adsorbent adsorbate necessary for refrigeration calculation had been obtained. In this experiment methanol is used as the refrigerant medium. The amollnt of methanol adsorbed by the activated carbon was measured as a function of temperature of the activated carbon. During the experiment, the temperature of the unadsorbed methanol was kept constant. From Dubinin-Astakhov equation, parameters of adsorption data were determined using graphical analysis. A Claperyon P-T-X (pressure, temperature and concentration) diagram was then constructed

    Quintessence with quadratic coupling to dark matter

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    We introduce a new form of coupling between dark energy and dark matter that is quadratic in their energy densities. Then we investigate the background dynamics when dark energy is in the form of exponential quintessence. The three types of quadratic coupling all admit late-time accelerating critical points, but these are not scaling solutions. We also show that two types of coupling allow for a suitable matter era at early times and acceleration at late times, while the third type of coupling does not admit a suitable matter era.Comment: 11 pages, 8 figures, revte

    Data Subset-Based Methods of Inference for Spatial Individual Level Epidemic Models

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    Mathematical models are essential to understand infectious disease dynamics, enabling to control the spread of those diseases and preparing for public health measures. Since time and space are important factors affecting the transmission of infectious diseases, spatial individual-level models (ILM) with both temporal and spatial information are developed. Typically, Markov Chain Monte Carlo (MCMC) methods are utilized for the inference of ILM. Nonetheless, this approach can be computationally intensive for complex or large models, resulting in repeated likelihood calculations. This thesis explores various spatial and temporal subset methods to conduct statistical inference for spatial epidemic models, aiming to provide appropriate parameter estimates with minimum computational resources. In this thesis, we utilize the spatial ILM with the Euclidean distance between susceptible individuals and infectious individuals as a kernel function

    Mechanisms of Fractal Formation in Colloidal Carbon-Bearing Natural System

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    By using the advanced nano-approach processes and phenomena in self-organizing colloidal systems are studied. The conditions of appearance of self-organized phenomena are determined and also ranges of operation of diffusion, capillary, and fractalization mechanisms are found. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3363

    3D-Self-Assemblage and Self-Organization on Natural Colloidal Microinclusions in Mineral Sediments

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    The results of micro- and nanoscale research of fractal structure sediments from mineral water re-ceived by the drop method are given. Qualitative analysis of the underlying physical phenomena, allowed us to establish the conditions of their 3D-fractalization that consider the size of colloidal nanoparticles, its location and height from the drop center : rmin Rmax hmax and rmax Rmin hmin. It is shown that the main contribution to 3D fractalization is due to surface tension forces and the Coulomb force interaction. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3625

    Self-assembly and Self-organization Processes of Carbon Nanotubes in the Colloidal Systems

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    The features and patterns of self-organization processes in the diffusion-limited conditions (method of drops) of carbon-containing compounds and carbon nanotubes have been studied. The results of the research influence of the substrate temperature and solvent on the formation of nanoscale fractal structures in sediments of colloidal solutions are provided

    Self-assembly and Self-organization Processes of Carbon Nanotubes in the Colloidal Systems

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    The features and patterns of self-organization processes in the diffusion-limited conditions (method of drops) of carbon-containing compounds and carbon nanotubes have been studied. The results of the research influence of the substrate temperature and solvent on the formation of nanoscale fractal structures in sediments of colloidal solutions are provided

    Assessment of HIV testing among young methamphetamine users in Muse, Northern Shan State, Myanmar

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    Background Methamphetamine (MA) use has a strong correlation with risky sexual behaviors, and thus may be triggering the growing HIV epidemic in Myanmar. Although methamphetamine use is a serious public health concern, only a few studies have examined HIV testing among young drug users. This study aimed to examine how predisposing, enabling and need factors affect HIV testing among young MA users. Methods A cross-sectional study was conducted from January to March 2013 in Muse city in the Northern Shan State of Myanmar. Using a respondent-driven sampling method, 776 MA users aged 18-24 years were recruited. The main outcome of interest was whether participants had ever been tested for HIV. Descriptive statistics and multivariate logistic regression were applied in this study. Results Approximately 14.7% of young MA users had ever been tested for HIV. Significant positive predictors of HIV testing included predisposing factors such as being a female MA user, having had higher education, and currently living with one’s spouse/sexual partner. Significant enabling factors included being employed and having ever visited NGO clinics or met NGO workers. Significant need factors were having ever been diagnosed with an STI and having ever wanted to receive help to stop drug use. Conclusions Predisposing, enabling and need factors were significant contributors affecting uptake of HIV testing among young MA users. Integrating HIV testing into STI treatment programs, alongside general expansion of HIV testing services may be effective in increasing HIV testing uptake among young MA users
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