376 research outputs found

    Effects of contact resistance and metal additives in finned-tube adsorbent beds on the performance of silica gel/water adsorption chiller

    Get PDF
    Recently interest in adsorption cooling systems has increased due to their capability to utilise low grade heat sources and environmentally friendly refrigerants. Currently, most of the commercially available adsorption cooling systems utilise granular packed adsorbent beds. Enhancing the heat transfer process inside the adsorbent bed will improve the overall efficiency of the adsorption system. Using recently developed empirical lumped analytical simulation model for a 450 kW two-bed silica gel/water adsorption chiller, this paper theoretically investigates the effects of various adsorbent bed heat transfer enhancement techniques on the adsorption system cooling capacity. Firstly, coating the first adsorbent layer to the metal part and packing the rest of adsorbent granules to eliminate the thermal contact resistance between heat exchanger metal and granules while keeping the same level of permeability. Secondly, adding metal particles to the adsorbent in order to enhance the granules thermal conductivity. The effective thermal conductivity of adsorbent/metal mixtures were determined and validated by comparing it with published experimental data. Also, the combined effect of using both techniques simultaneously was investigated. All these investigations were carried out at various adsorption bed fin spacing. Results of the combined techniques showed that the enhancement in the cooling capacity and system coefficient of performance (COP) increased with increasing the fin spacing ratio to reach maximum of 25% and 10% respectively at fin spacing ratio of 2

    An Artistic Vision of Using Polyurethane Foam in Drapping Fictional Costumes Designs to Achieve Sustainable Development

    Get PDF
    One of the aspects of the modern era is leaving more room for imagination and experimentation. Costumes design in general and fictional costumes design in particular are among the areas that need a lot of experimentation, especially with new, non-traditional materials. This is what encouraged the researchers to choose the polyurethane foam as a non-traditional material to design fictional costumes in order to achieve sustainable development goals. The research aims at clarifying the characteristics of the polyurethane foam and it’s Forming instead of plastic capabilities in the field of Costumes design, and providing proposals for fictional costumes designs with this material, in addition to achieving the sustainable development goals; such as, adopting sustainable production and consumption patterns, and stimulating innovation. The research findings state the possibility of achieving new visions of using the polyurethane foam to design and create fictional costumes in order to achieve the goals of sustainable development

    Impact of Augmented Reality on Pattern Designing Using Origami-Style among Clothing and Textile Students

    Get PDF
    The study aimed to examine the effects of augmented reality technology on the development of origami-style pattern designing skills among female students in the clothing and textile field, as well as to explore their attitudes towards this technology. The quasi-experimental approach was employed to achieve the research objectives, with a sample of 24 female students from the Fourth Grade of the Department of Clothing and Textile, Faculty of Home Economics at Al-Azhar University. The participants were divided into two groups: a control group of 12 students who studied in the traditional way, and an experimental group of 12 students who used augmented reality technology to learn. The study was conducted in the second semester of the academic year 2020/2021. The results showed that there was a statistically significant difference (at a significance level of 0.01) between the average scores of the control group and the experimental group in both cognitive achievement and skill performance, with the experimental group performing better. Additionally, the retention of learned information was higher among the experimental group, and they had a more positive attitude towards using augmented reality technology in learning

    The homotopy theory of simplicial props

    Full text link
    The category of (colored) props is an enhancement of the category of colored operads, and thus of the category of small categories. In this paper, the second in a series on "higher props," we show that the category of all small colored simplicial props admits a cofibrantly generated model category structure. With this model structure, the forgetful functor from props to operads is a right Quillen functor.Comment: Final version, to appear in Israel J. Mat

    Breast cancer image classification using pattern-based Hyper Conceptual Sampling method

    Get PDF
    The increase in biomedical data has given rise to the need for developing data sampling techniques. With the emergence of big data and the rise of popularity of data science, sampling or reduction techniques have been assistive to significantly hasten the data analytics process. Intuitively, without sampling techniques, it would be difficult to efficiently extract useful patterns from a large dataset. However, by using sampling techniques, data analysis can effectively be performed on huge datasets, to produce a relatively small portion of data, which extracts the most representative objects from the original dataset. However, to reach effective conclusions and predictions, the samples should preserve the data behavior. In this paper, we propose a unique data sampling technique which exploits the notion of formal concept analysis. Machine learning experiments are performed on the resulting sample to evaluate quality, and the performance of our method is compared with another sampling technique proposed in the literature. The results demonstrate the effectiveness and competitiveness of the proposed approach in terms of sample size and quality, as determined by accuracy and the F1-measure. 2018This contribution was made possible by NPRP-07-794-1-145 grant from the Qatar National Research Fund (a member of Qatar foundation). The statements made herein are solely the responsibility of the authors.Scopu

    Mutual Relationships: Saudi Universities and The Private Sector for Economic Development

    Get PDF
    The purpose of this research is to determine the level of the mutual relationship between Saudi universities and the private sector to achieve Economic development in light of the Kingdoms 2030 vision. The researcher relied heavily on the questionnaire as the primary instrument for data collection for the study, employing a descriptive research design and a quantitative methodology in order to accomplish the goals of the study. The investigation was carried out with a sample size of 180 universities leaders in the southern region of Saudi Arabia, all of them were chosen at random. The findings of this study indicated that leaders had high expectations for a mutual relationship between Saudi universities and the private sector. In addition, the findings demonstrated that there are no statistically significant variations in the mutual relationship between Saudi universities and the private sector with regard to the variables of academic rank, and years of experience

    Development of an LC-MS Method for Measuring TNF in Human Vaginal Tissue

    Get PDF
    A sensitive, accurate, and precise liquid chromatography–mass spectrometry assay for the determination of tenofovir (TNF) in human vaginal tissue was developed and validated. After homogenization of the tissue, solid-phase extraction on Varian Bond Elut-C18 column was used for sample clean up. Chromatographic separation of TNF and the internal standard (tolbutamide) was achieved with a Varian Polaris 3C18-A reversed-phase analytical column (150 mm × 2 mm). A gradient method using 0.1% formic acid in water and 0.1% formic acid in acetonitrile was employed. Detection of TNF and tolbutamide was achieved by electrospray ionization mass spectrometry in the positive ion mode using 288.05 and 271.00 m/z, respectively. Linear TNF calibration curves were obtained between 1–1,000 ng/mL with a correlation coefficient (r2) greater than 0.999. Intra-and inter-day accuracy for TNF ranged from 89.7% and 109.4% and from 97.3% and 104.9%, and precision ranged from 1.3% and 10.9% and 2.6% and 9.0%, respectively. This is the first validated method developed to quantitate TNF in human tissues
    corecore