Properties of concrete at elevated temperatures using selected brands of ordinary Portland Cement

In recent times, there has been a serious controversy as to whether the different brands of OPC commonly used in Nigeria can attain adequate strength and even the Standard Organization of Nigeria (SON) attributed the incidences of building collapse in the country to this assumption. This has prompted researchers to investigate the properties of concrete produced with various brands of the cement produced in the country. This study therefore evaluates the properties of concrete made with different Nigerian brands of OPC exposed to an elevated temperature. Four brands of Ordinary Portland Cement commonly available in Nigeria were used in this project to produce different concrete specimens which were labeled A, B, C and D. a total of seventy two (72) specimens of size 100mm x 100mm x 100mm cubes were produced using a nominal mix of 1:2:4 and W/C ratio of 0.55. After curing the concrete specimens produced in water for 28days, 36 of the specimens were exposed to an elevated temperature of 800oC, 1000oC and 1200oC for 3hrs while the remaining 36 were used as control. Thereafter, compressive strength of the concrete specimens was determined. The average compressive strength obtained for concrete specimen made with cement brand A, B, C and D exposed to 800oC were 6.27N/mm2, 5.08N/mm2, 5N/mm2 and 6.4N/mm2 respectively while at 1000oC the compressive strength values were 3.03N/mm2, 1.97N/mm2, 2.57N/mm2, and 3.27N/mm2 respectively. At 1200oC, all the concrete specimens melted. Result obtained shows that concrete specimen produced with cement brand D has better compressive strengths when compared to A, B and C. It is concluded that cement D showed higher compressive strength after its exposure to elevated temperature. It is therefore recommends that cement D be used in areas where concrete is likely to be exposed to high elevated temperature.Keywords: Brands of Cement, Elevated Temperature, Properties, Compressive Strengt

МОБИЛЬНОЕ ОЗЕЛЕНЕНИЕ ЗДАНИЙ

The article considers the options of gardening in a densely built urban environment. It shows the role of green spaces, their impact on environmental parts. The main purpose is to analyze the reasons of influence of cities and human activities on the environment and solutions of this problem. The main problem, which is considered by the author: an analyze of the causes of environmental problems in the city; description of the main environmental problems of the cities; offer ways to improve the environmental condition of the city, through the introduction of mobile landscaping systems, which is shown on the experience in solving this problem in Singapore, with the possibility of its implementation in Moscow. An example of the ecological Park in Singapore, which is built according to the program of landscaping and environmental improvements of densely built-up city.В статье рассмотрены варианты озеленения в городской среде при плотной застройке, роль зеленых насаждений, их влияние на экологическую среду в городе. Главная цель - проанализировать причины воздействия города и деятельности человека на экологию и пути решения данной проблемы. Основные задачи, рассмотренные в статье: проанализировать причины возникновения экологических проблем в городе; дать характеристику основных экологических проблем городов; рассмотреть пути улучшения экологического состояния города с помощью внедрения мобильных систем озеленения. Показан опыт Сингапура в решении данной проблемы, рассмотрена возможность ее реализации в Москве. Приводится пример экологического парка в Сингапуре, построенного в рамках программы озеленения и улучшения экологической обстановки мегаполиса

Design and Fabrication of Radio Frequency Amplifier with 3 dB π-Network Attenuator Isolation

This paper presents the design and fabrication of radio frequency amplifier (RFA), which operates at 5.8 GHz unlicensed frequency for WiMAX application. The RFA designed used T-matching network consisting of lump reactive elements, 3 dB attenuator and microstrip line at the input and output impedance. The RFA developed in this project contribute a gain of 15.6 dB with overall noise figure of 2.4 dB. The overall measured bandwidth is 1.240 GHz with S parameters S11, S12 and S22 measured are -12.4 dB, -25.5 dB and -12.3 dB respectively. The isolation result shows that there is a significant contribution using 3 dB π-network. The RFA used FET transistor EPA018A from Excelics Semiconductor Inc

Automated grade classification of oral epithelial dysplasia using morphometric analysis of histology images

Oral dysplasia is a pre-malignant stage of oral epithelial carcinomas, e.g., oral squamous cell carcinoma, where significant changes in tissue layers and cells can be observed under the microscope. However, malignancy can be reverted or cured using proper medication or surgery if the grade of malignancy is assessed properly. The assessment of correct grade is therefore critical in patient management as it can change the treatment decisions and prognosis for the dysplastic lesion. This assessment is highly challenging due to considerable inter- and intraobserver variability in pathologists’ agreement, which highlights the need for an automated grading system that can predict more accurate and reliable grade. Recent advancements have made it possible for digital pathology (DP) and artificial intelligence (AI) to join forces from the digitization of tissue slides into images and using those images to train and predict more accurate grades using complex AI models. In this regard, we propose a novel morphometric approach exploiting the architectural features in dysplastic lesions i.e., irregular epithelial stratification where we measure the widths of different layers of the epithelium from the boundary layer i.e., keratin projecting inwards to the epithelium and basal layers to the rest of the tissue section from a clinically significant viewpoint

WITHDRAWN: Comparative study between bio-and phosphorus fertilization on growth, yield and fruit quality of banana (Musa spp.) grown on sandy soil

This article has been withdrawn at the request of the editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy

Mechanical Properties Of Stored Red Blood Cells Using Optical Tweezers

We have developed a method for measuring the red blood cell (RBC) membrane overall elasticity μ by measuring the deformation of the cells when dragged at a constant velocity through a plasma fluid by an optical tweezers. The deformability of erythrocytes is a critical determinant of blood flow in the microcirculation. We tested our method and hydrodynamic models, which included the presence of two walls, by measuring the RBC deformation as a function of drag velocity and of the distance to the walls. The capability and sensitivity of this method can be evaluated by its application to a variety of studies, such as, the measurement of RBC elasticity of sickle cell anemia patients comparing homozygous (HbSS), including patients taking hydroxyrea (HU) and heterozygous (HbAS) with normal donors and the RBC elasticity measurement of gamma irradiated stored blood for transfusion to immunosupressed patients as a function of time and dose. These studies show that the technique has the sensitivity to discriminate heterozygous and homozygous sickle cell anemia patients from normal donors and even follow the course of HU treatment of Homozygous patients. The gamma irradiation studies show that there is no significant change in RBC elasticity over time for up to 14 days of storage, regardless of whether the unit was irradiated or not, but there was a huge change in the measured elasticity for the RBC units stored for more than 21 days after irradiation. These finds are important for the assessment of stored irradiated RBC viability for transfusion purposes because the present protocol consider 28 storage days after irradiation as the limit for the RBC usage.593016Ashkin, A., Dziedzic, J.M., Optical trapping and manipulation of viruses and bacteria (1987) Science, 235, pp. 1517-1520Barjas-Castro, M.L., Brandão, M.M., Fontes, A., Costa, F.F., Cesar, C.L., Saad, S.T.O., Elastic properties of irradiated red blood cell units measured by optical tweezer (2002) Transfusion, 42, pp. 1196-1199Brandão, M.M., Fontes, A., Barjas-Castro, M.L., Barbosa, L.C., Costa, F.F., Cesar, C.L., Saad, S.T.O., Optical tweezers for measuring red blood cell elasticity: Application to the study of drug response in sickle cell disease (2003) European Journal of Haematology, 70, pp. 207-211Williamson, L.M., Warwick, R.M., Transfusion-associated graft-versus-host disease and its prevention (1995) Blood Rev., 9, pp. 251-261Button, L.N., Dewolf, W.C., Newburger, P.E., The effecr of irradiation on blood components (1981) Transfusion, 21, pp. 419-426Platt, O.S., The sickle syndrome (1995) Blood: Principles and Practice of Hematology, , R. I Hadlin, S. E. Lux, T. P. Stossel, J. B. Lippincott, PhiladelphiaBallas, S.K., Dover, G.J., Charache, S., Effect of hydroxyurea on the rheological properties of sickle erythrocytes in vivo (1989) Am. J. Hematol, 32, pp. 104-111Groner, W., Mohandas, N., Bessis, M., New optical technique for measuring erythrocyte deformability with the ektacytometer (1980) Clin. Chem., 26, pp. 1435-1442De Franceschi, L., Bachir, D., Galacteros, F., Tchernia, G., Cynober, T., Alper, S., Platt, O., Brugnara, C., Oral magnesium supplements reduce erythrocyte dehydration in patients with sickle cell disease (1997) J Clin Invest, 100, pp. 1847-1852Hochmuth, R.M., Worthy, P.R., Evans, E.A., Red cell extensional recovery and the determination of membrane viscosity (1979) Biophys. J., 26, pp. 101-114Evans, E.A., La Celle, P.L., Intrinsic material properties of the erythrocyte membrane indicated by mechanical analysis of deformation (1975) Blood, 45, pp. 29-43Itoh, T., Chien, S., Usami, S., Effects of hemoglobin concentration on deformability of individual sickle cells after deoxygenation (1995) Blood, 85, pp. 2245-2253Evans, E.A., Mohandas, N., Membrane-associated sickle hemoglobin: A major determinant of sickle erythrocyte rigidity (1987) Blood, 70, pp. 1443-1449Dong, C., Chadwick, R.S., Schechter, A.N., Influence of sickle hemoglobin polymerization and membrane properties on deformability of sickle erythrocytes in the microcirculation (1992) Biophys. J., 63, pp. 774-783Suzuki, Y., Tateishi, N., Cicha, I., Decreased deformability of the X-ray irradiated red blood cells stored in manitol-adenine-phosphate medium (2000) Clin. Hemorheol. Micro-cire., 22, pp. 131-14

Hot red pepper powder as a safe alternative to antibiotics in organic poultry feed: An updated review

Globally, several studies have investigated the utilization and efficacy of promising medicinal herbal plants to enhance livestock and poultry production. The most commonly investigated phytobiotics in broiler ration were oregano, garlic, thyme, rosemary, black pepper, hot red pepper (HRP), and sage. Phytobiotics are classified on the basis of the medicinal properties of plants, their essential oil extracts, and their bioactive compounds. The majority of bioactive compounds in plants are secondary metabolites, such as terpenoids, phenolic, glycosides, and alkaloids. The composition and concentrations of these bioactive constitutes vary according to their biological factors and manufacturing and storage conditions. Furthermore, HRP is one of the most important and widely used spices in the human diet. Capsicum annum, that is, HRP, is a species of the plant genus Capsicum (pepper), which is a species native to southern North America and northern South America and is widely grown and utilized for its fresh or cooked fruits. Moreover, these fruits may be used as dried powders or processed forms of oleoresins. Researches have proven that C. annuum is the only plant that produces the alkaloid capsaicinoids. Approximately 48% of its active substances are capsaicin (8-methyl-N-vanillyl-6-nonemide), the main active compound responsible for the intense effects of HRP varieties and the main component inducing the hot flavor. This review aimed to highlight the effects of HRP as a phytobiotic in broiler nutrition and its mode of action as a possible alternative to antibiotics and clarify its impact on broiler and layer productivity

Determinants of Cluster Size in Large, Population-Based Molecular Epidemiology Study of Tuberculosis, Northern Malawi

Both epidemiologic and strain-related factors may contribute to large clusters of tuberculosis patients

Temperature Regulation of Photovoltaic Module Using Phase Change Material: A Numerical Analysis and Experimental Investigation

This work represents an effective design of a temperature regulated PV module by integrating phase change materials for Malaysian weather condition. Through the numerical analysis and experimental investigation it has been shown that if a PCM layer of width 0.02 m of RT 35 is used as a cooling arrangement with a PV module, the surface temperature of the module is reduced by 10°C, which remains constant for a period of 4–6 hours. This reduction of temperature implies the increase in conversion efficiency of the module. Experiment as well as investigation has been carried out considering typical Malaysian weather. Obtained result has been validated by using experimental prototype and comparative analysis