Design and experimental study of a solar system for heating water utilizing a linear Fresnel reflector

This work presents a design and an experimental study of a linear Fresnel reflector solar with trapezoidal cavity. This prototype is used for heating the tap water. The reflector was designed, constructed and tested in mechanical engineering department, University of Blida 1, Algeria. Various combinations of reflecting mirrors were tried to achieve hot temperature at the concentration line. The absorber tube was made of copper; it was painted with black paint and covered by selective suitable surface. The quantity of heat available to the absorber tubes was evaluated and compared with 7, 9 and 11 mirrors. The experimental works on the concentrator were accomplished within two days in the winter of 2015. Water temperature reached a maximum of 74 °C with eleven reflective mirrors. The maximum value of the thermal efficiency is 29.21%. The results obtained are very encouraging for using linear Fresnel concentrator in the solar fields allocated to the domestics and industrial water-heaters.Keywords: Solar energy; design, linear Fresnel reflector; thermal efficiency; solarwater-heate

Ab-initio study of the bandgap engineering of Al(1-x)Ga(x)N for optoelectronic applications

A theoretical study of Al(1-x)Ga(x)N, based on full-potential linearized augmented plane wave method, is used to investigate the variations in the bandgap, optical properties and non-linear behavior of the compound with the variation of Ga concentration. It is found that the bandgap decreases with the increase of Ga in Al(1-x)Ga(x)N. A maximum value of 5.5 eV is determined for the bandgap of pure AlN which reaches to minimum value of 3.0 eV when Al is completely replaced by Ga. The static index of refraction and dielectric constant decreases with the increase in bandgap of the material, assigning a high index of refraction to pure GaN when compared to pure AlN. The refractive index drops below 1 for photon energies larger than 14 eV results group velocity of the incident radiation higher than the vacuum velocity of light. This astonishing result shows that at higher energies the optical properties of the material shifts from linear to non-linear. Furthermore, frequency dependent reflectivity and absorption coefficients show that peak value of the absorption coefficient and reflectivity shifts towards lower energy in the UV spectrum with the increase in Ga concentration. This comprehensive theoretical study of the optoelectronic properties of the alloys is presented for the first time which predicts that the material can be effectively used in the optical devices working in the visible and UV spectrum.Comment: 18 pages, 7 figure

Excitonic quasiparticles in a spin-orbit Mott insulator

In condensed matter systems, out of a large number of interacting degrees of freedom emerge weakly coupled particles, in terms of which most physical properties are described. For example, Landau quasiparticles (QP) determine all electronic properties of a normal metal. The lack of identification of such QPs is major barrier for understanding myriad exotic properties of correlated electrons, such as unconventional superconductivity and non-Fermi liquid behaviours. Here, we report the observation of a composite particle in a Mott insulator Sr2IrO4---and exciton dressed with magnons---that propagates with the canonical characteristics of a QP: a finite QP residue and a lifetime longer than the hopping time scale. The dynamics of this charge-neutral bosonic excitation mirrors the fundamental process of the analogous one-hole propagation in the background of ordered spins, for which a well-defined QP has never been observed. The much narrower linewidth of the exciton reveals the same intrinsic dynamics that is obscured for the hole and is intimately related to the mechanism of high temperature superconductivity.Comment: submitted versio

Pengorganisasian Pkbm Sari Kecamatan Rumbai Pesisir Kota Pekanbaru

Abstarct: The purpose of this study was to determine the organizing principle of CLC Sari Tassel Coastal District of the city of Pekanbaru, namely: (i) the purpose of the organization, (ii) organizing the division of labor, (iii) the responsibility of the organizing authority, (iv) coordination, focus of the study include aspects where (place), actors (actor), and activity (activity) performed by CLC Sari Tassel Coastal District of the city of Pekanbaru.This study used a qualitative research method of this type of ethnography, ethnography is to describe culture as such or seek buadaya theme.Informants in this study is the leaders of the CLC Sari as an informant core, administrative staff as informants control, and tutors as key informants. As for how to collect the data is by using the method of observation, interviews, and documentation.Collecting and analyzing data using Spradley models are: (1) the domain analysis, (2) analysis of taxonomy, (3) analysis komponensial and (4) analysis of the cultural theme. In accordance with the appropriate discussion and research purposes, it can be concluded: 1). The aim is to explore the potential of community organizing in learning needs, foster interest in learning to the learners as well as take advantage of the potential that exists within themselves wrga learning. 2). The division of labor is the organizing institution leaders CLC Sari divide the work in accordance with their expertise and their functions. 3). Responsibility in organizing authority is the leader of the institution determines that the program will be held in accordance with the needs of the learners. 4). Coordination is a leader in organizing CLC Sari organize and plan all the programs on the CLC and assisted by the members. 5). Responsibilities in the organization are administrative staff and tutors are given the task of taking care of correspondence and teaching. 6). Labor discipline in the organization are the actors who have been given the task of carrying out their duties properly. 7). Motivation in the organization are the actors provide motivation among fellow members and residents to learn

Kinase profiling of liposarcomas using RNAi and drug screening assays identified druggable targets.

BackgroundLiposarcoma, the most common soft tissue tumor, is understudied cancer, and limited progress has been made in the treatment of metastatic disease. The Achilles heel of cancer often is their kinases that are excellent therapeutic targets. However, very limited knowledge exists of therapeutic critical kinase targets in liposarcoma that could be potentially used in disease management.MethodsLarge RNAi and small-molecule tyrosine kinase inhibitor screens were performed against the proliferative capacity of liposarcoma cell lines of different subtypes. Each small molecule inhibitor was either FDA approved or in a clinical trial.ResultsScreening assays identified several previously unrecognized targets including PTK2 and KIT in liposarcoma. We also observed that ponatinib, multi-targeted tyrosine kinase inhibitor, was the most effective drug with anti-growth effects against all cell lines. In vitro assays showed that ponatinib inhibited the clonogenic proliferation of liposarcoma, and this anti-growth effect was associated with apoptosis and cell cycle arrest at the G0/G1 phase as well as a decrease in the KIT signaling pathway. In addition, ponatinib inhibited in vivo growth of liposarcoma in a xenograft model.ConclusionsTwo large-scale kinase screenings identified novel liposarcoma targets and a FDA-approved inhibitor, ponatinib with clear anti-liposarcoma activity highlighting its potential therapy for treatment of this deadly tumor

Comparative yield and characterization of flavonoids from the stem back and root of Blighia sapida

Flavonoids represent a wide spread group of water soluble phenolic derivatives, known for their medicinal effect. This paper is focused on identifying the functional groups present in flavonoids of Blighia sapida stem bark and root sample. The percentage yield was higher with methanol extract of the stem bark compared to the root. The GC-MS of methanol extract shows carboxylic acid which might be attributed to presence of lipids. The isolation of flavonoids by TLC and the FITR revealed the functional group –OH, C=O,CH which are majorly responsible for the medicinal effect.Keywords: Blighia sapida, characterization, comparative yield, Flavonoids, methanol extrac

Mtwara Regional and District Projections.

\ud This report presents population projections for the period 2003 to 2025 for Mtwara region and its districts. The projections were made using a Cohort Component Method (Spectrum System), whereby three components responsible for population change, namely: mortality, fertility and\ud migration were projected separately as well as HIV/AIDS prevalence. The projected components were then applied to 2002 midyear base population in order to come up with the desired projections from 2003 to 2025. The report gives mortality, fertility, migration and HIV/AIDS assumptions, and shows Mtwara’s demographic and socio-economic future trends. The results include estimated population by sex in single years and five-year age groups as well as some demographic indicators. Population growth for the period 2003 to 2025 shows an increase from 1.8 percent in 2003 (with a population of 1,145,655) to 2.0 percent in 2009 (with a population of 1,297,751) and will decrease gradually to 1.8 in 2025 (with a population of 1,724,679). Sex Ratio at birth is projected to increase from 90 male births per 100 females in 2003 to 97 male births per 100 females in 2025. Mortality estimates show that Infant Mortality Rate (IMR) is expected to decline for both sexes from 143 deaths per 1,000 live births in 2003 to 84 deaths per 1,000 live births in 2025. Under Five Mortality Rate (U5MR) for both sexes will also decline from 238 deaths per 1,000 live births in 2003 to 134 deaths per 1,000 live births in the year 2025. Life expectancy at birth for Mtwara will increase from 43 years in 2003 to 48 years in 2025 for both sexes. For male population, life expectancy at birth will increase from 43 years in year 2003 to 48 years in 2025, while for female population the life expectancy at birth will increase from 42 years in 2003 to 48 years in 2025. On fertility, TFR will decline from 4.9 children per woman in 2003 to 4.6 children per woman in 2025.\u