The hybrid Photovoltaic/Thermal systems are suffering from the low electrical performance as a result of elevated its temperature. Present work attempts to enhance the performance of a hybrid ...Photovoltaic/Trombe wall (PV/TW) system through employing a porous medium. In this article, the effect of porous medium, DC fan and glass cover on the performance of a PV/TW was accomplished by the design and implementation of an experimental system to achieve this target. The mathematical method to predict the performance of a PV/TW system was also offered based on a simplified concept of an energy balance. The results of the theoretical study agreed well with the practical results in terms of the estimated temperature of the solar cell.
The results revealed that incorporating the porous medium and DC fan offered favorable features of the system performance, while the glass cover has a conflict effect. It was confirmed that using porous medium and DC fan reduces the temperature of PV cell and increases the room temperature. Whereas, the presence of the glass cover in front of the system leads to elevate the temperatures of the room and solar cell. The presence of porous medium with DC fan increases the values of thermal and electrical efficiencies about 13% and 4%, respectively. Furthermore, the combined effect of porous medium with DC fan and glass cover increases the values of thermal and electrical efficiencies about 20% and 0.5%, respectively. It is recommended to integrate the PV/TW system with DC fan and porous medium for further conversion of solar radiation and improve building comfort conditions.
•In this paper, the influence of porous media on the performance of the PV/TW was achieved.•Inserting the porous medium inside the air duct of the PV/TW system enhances the system efficiencies.•Incorporating the PV/TW system with a DC fan improves the system performance.•The use of glass cover decreases the electrical efficiency, while, increasing thermal efficiency.
This article aims to study water-cooling effects on residual stress friction stir welding (FSW) of AA6068-T6 aluminum alloy. For this reason, the FSW and submerged FSW processes are simulated by ...computational fluid dynamic (CFD) method to study heat generation. The increment hole drilling technique was used to measure the residual stress of welded samples. The simulation results show that materials softening during the FSW process are more than submerged. This phenomenon caused the residual stress of the joint line in the submerged case to be lower than in the regular FSW joint. On the other hand, the results revealed that the maximum residual stresses in both cases are below the yielding strength of the AA6068-T6 aluminum alloy. The results indicated that the residual stress along the longitudinal direction of the joint line is much larger than the transverse direction in both samples.
In this study, the effects of the traverse and rotational velocities of the noncontact shoulder tool on the heat generation and heated flux during the friction stir joining of high-density polyamide ...6 (PA6) polymer were investigated. The computational fluid dynamics (CFD) method was employed to simulate the thermomechanical phenomena during the friction stir joining (FSJ) process of PA6. A developed model was used to consider the void formation and thermochemical properties of PA6. The surface and internal heat flow, material flow, and geometry of the joint were simulated, and an experimental study evaluated the simulation results. The simulation results indicated that the stir zone formed was smaller than regular joints with a noncontact shoulder tool. Despite the polymer’s traditional FSJ, heat generation and material flow do not differ significantly between advancing and retreating sides. On the other hand, the surface flow is not formed, and the surface temperature gradient is in a narrow line behind the tool. The material velocity increased at higher rotational speed and lower transverse velocity and in the stir zone with more giant geometry forms. The maximum generated heat was 204 °C, and the maximum material velocity was predicted at 0.44 m/s in the stir zone, achieved at 440 rpm and 40 mm/min tool velocities.
Hormonal alterations and lowered immunity during pregnancy aggravated by poor oral hygiene increase the risk of pregnant women of developing oral diseases. We conducted this cross-sectional study to ...examine the role of oral and prenatal health providers in promoting dental care for pregnant women attending primary healthcare centers (PHCs) in Saudi Arabia.
An online questionnaire was sent to a random sample of women who attended PHCs in Jeddah, during 2018-2019. From a total of 1350 women who responded to our questionnaire, 515 women reported having a dental visit before pregnancy. These women comprised our study sample. Bivariate analyses and multiple logistic regression models were conducted to examine associations between oral practices of dental and prenatal health providers (exposures) and women's utilization of dental care during pregnancy (outcome). Covariates included age, education (< 12 years of education, 12 years of education, and > 12 years of education), family income (≤ 5,000, 5,001-7,000, 7,001-10,000, and > 10,000 Saudi Riyals), health insurance (yes/no), nationality (Saudi Arabian/non-Saudi Arabian), and presence of dental problems, such as toothache, dental caries, gingival inflammation, and the need for dental extractions.
Only 30.0% of women were informed by a dentist during their dental visit before pregnancy about the importance of visiting a dentist during pregnancy. About 37.0% of women were asked about oral health, 34.4% were informed about the importance of dental care during pregnancy, and 33.2% had their mouths inspected by prenatal health providers. Women informed by dentists about the importance of dental visits during pregnancy were twice as likely (Odds ratio OR: 2.42, 95% confidence interval CI: 1.63-3.60) to visit a dentist during pregnancy. Women who were referred to dentists, had their mouth inspected, or were advised to visit a dentist during pregnancy by prenatal providers were 4.29 (95% CI: 2.67-6.88), 3.79 (95% CI: 2.47-5.82), and 3.37 (95% CI: 2.16-5.27) times as likely to visit a dentist during pregnancy.
The partaking of oral and prenatal healthcare providers in evidence-based oral health promotion practices, antenatal-dental collaboration, and closing the referral loop increase pregnant women's access to and utilization of preventive and treatment dental services.
Aim
To provide an overview of nursing research in Jordan based on the topic researched, source and setting of data collection, methodology, theoretical framework used and source of funding.
...Background
Nursing research contributes to nursing education, clinical practice, health policy and the establishment of nursing research priorities in Jordan to guide future research.
Methods
Databases such as MEDLINE, CINAHL, Google Scholar, PubMed and national sources were searched for published articles related to nursing in Jordan through a range of keywords. Articles were included in the analysis if they were published in English or Arabic through December 2012.
Findings
The search resulted in the identification of 999 publications, from which 462 articles met the inclusion criteria and were included in the review. The highest percentage of studies (23% of articles) focused on nursing management issues. Forty‐four per cent were conducted in a hospital setting; only six studies used a nursing theory. Seventy‐seven per cent of the studies were quantitative and 29.0% were funded mostly by universities. Twenty‐one per cent were not directly related to improving nursing education or practice in Jordan. A Jordanian Database for nursing research was developed as a result of this review.
Discussion
Jordanian nurses have slowly started to build nursing research, the real nursing research work in Jordan started with the return of the first PhD graduate to Jordan in 1986.
Conclusion
Jordanian nurses in collaboration with international colleagues were motivated to publish research and build the body of nursing knowledge.
The aluminum strength-to-weight ratio has become a highly significant factor in industrial applications. Placing stiffening ribs along the surface can significantly improve the panel's resistance to ...bending and compression in aluminum alloys. This study used single-point incremental forming (SPIF) to fabricate stiffening ribs for 1 mm and 3 mm thick aluminum alloy EN AW-2024-T3 sheets. A universal compression machine was used to investigate sheet deformation. The resulting deformation was examined using non-contact digital image correlation (DIC) based on several high-resolution cameras. The results showed that deformation progressively escalated from the edges toward the center, and the highest buckling values were confined within the non-strengthened area. Specimens with a larger thickness (3 mm) showed better effectiveness against buckling and bending for each applied load: 8 kN or 10 kN. Additionally, the displacement from the sheet surface decreased by 60% for sheets 3 mm thick and by half for sheets 1 mm thick, which indicated that thicker sheets could resist deformation better.
Friction stir welding (FSW) of polymeric materials has recently attracted significant attention. Herein, we present the effect of the tool pin profile on the FSW of high-density polyethylene (HDPE) ...joints through joint experimental analysis and thermomechanical simulations. For analysis of pin profile effects on the thermomechanical properties of HDPE joints, frustum (FPT), cubic (CPT), and triangular (TPT) pin shapes were selected in this study. This research investigated the heat generation of the parts of the different tools as well as heat flux (internal and surface). The results revealed that the heat generation in pins with more edges (cubic (96 °C) and triangular (94 °C)) was greater than in pins with a smooth shape (frustum (91 °C)). The higher heat generation caused the heat flux on the surface of the HDPE from the cubic pin profile to be greater than for other joints. Due to the properties of HDPE, higher heat generation caused higher material velocity in the stirring zone, where the velocity of the materials in TPT, CPT, and FPT pins were 0.41 m/s, 0.42 m/s, and 0.4 m/s, respectively. The simulation results show sharp-edged pins, such as triangular and cubic, lead to over-stirring action and internal voids formed along the joint line. Furthermore, the simulation results indicated that the size of the stirred zones (SZs) of the FPT, TPT, and CPT samples were 17 mm2, 19 mm2, and 21 mm2, respectively, which is around three times the corresponding values in the HAZ.
The authors report on highly scaled 60 nm gate length graded-channel AlGaN/GaN high electron mobility transistors (HEMTs) with a record power added efficiency (PAE) of 75% at 2.1 W/mm power density ...at Vdd = 10 V and the PAE of 65% at 3.0 W/mm power density at 30 GHz at Vdd = 14 V. Under two-tone power measurement, the graded-channel AlGaN/GaN HEMTs demonstrated similar power performance with peak PAE >70% at 30 GHz. This novel channel design shows great promise for high-efficiency millimetre-wave (mmW) power amplifiers up to 3 W/mm RF power density operation.
Global energy demand for the future can be met using renewable energy resources, and one of its harvesting tools is the photovoltaic (PV) technology. The combination of solar cell technology and ...Trombe wall is one of the most important research topics at present. PV‐Trombe walls are receiving great attention because of their applications for simultaneous electricity generation and heating. In this article, a review of available literature covers different designs of a PV‐Trombe wall system besides its thermal and electrical applications. The review covers in detail the influence of design and operational parameters including the glass cover, use of direct current fan, facade width, air vent, air gap thickness, thermal insulation, packing factor, coverage, heat storage, air mass flow rate, PV cell cooling, southern windows, and tilt angle of solar cell on the performance of PV‐Trombe walls. Furthermore, comparison between the PV‐Trombe wall system and classical Trombe wall as well as the applicability of this novel system are revealed. This review article is beneficial to engineers and researchers and can provide information for future studies.
The neglected tropical disease leishmaniasis, caused by Leishmania spp., is becoming more problematic due to the emergence of drug-resistant strains. Therefore, new drugs to treat leishmaniasis, with ...novel mechanisms of action, are urgently required. Strathclyde minor groove binders (S-MGBs) are an emerging class of anti-infective agent that have been shown to have potent activity against various bacteria, viruses, fungi and parasites. Herein, it is shown that S-MGBs have potent activity against
, and that an N-oxide derivation of the tertiary amine tail of typical S-MGBs leads to selective anti-leishmanial activity. Additionally, using S-MGB-219, the N-oxide derivation is shown to retain strong binding to DNA as a 2:1 dimer. These findings support the further study of anti-leishmanial S-MGBs as novel therapeutics.
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