57 research outputs found
Characterization of the interfacial interaction of PCC nano powder with tallow fatty acids for HDPE compounding
No full textMugar Precipitated Calcium Carbonate (MPCC) Nano-Powders were synthesized using a solution approach and coated with tallow fatty acid to enhance their compatibility with high-density polyethylene (HDPE) composites. The coated MPCC (MCPCC) nanoparticles were incorporated into HDPE to improve interfacial interaction, tensile strength, and toughness. The study investigated the effects of varying MPCC weight percentages (0–40 %) and the role of the tallow fatty acid coating in optimizing composite properties. Thermal, structural, and morphological analyses, including TGA, XRD, FTIR, DLS, and SEM, were conducted to evaluate the dispersion and interfacial interactions between MPCC and the HDPE matrix. The results demonstrated that the tallow coating significantly improved the mechanical properties of the composites. Notably, the coated MPCC nanoparticles enhanced tensile strength and toughness compared to uncoated counterparts, with the coating also contributing to better thermal stability. The research highlights the innovative use of tallow fatty acid as a coating agent to improve filler-matrix compatibility, a distinction from previous studies that often rely on synthetic or non-biodegradable coatings. This approach not only enhances the mechanical and thermal properties of HDPE composites but also offers a sustainable alternative for industrial applications. Further optimization of coating processes and particle size distribution could lead to even greater improvements in composite performance
Evidence-based intrapartum care practice and associated factors among obstetrics workers in Ethiopia, systematic review and meta-analysis
No full textBackground: Evidence-based practice is defined as using the best available research and clinical evidence by incorporating patients’ values and preferences for their health needs. The use of evidence-based intrapartum care practices is an essential tool to improve the quality of obstetrics care. Objective: The primary objective of this study was to determine the prevalence of evidence-based intrapartum care and associated factors among obstetrics care providers in Ethiopia. Method: Important articles were retrieved from universally accepted and used databases, including Cochran, PubMed, HINARI, Google Scholar, Web of Science, African OnLine, and repositories of Ethiopian Universities. We extracted articles by using a standard JOANNA Briggs Institute data extraction sheet. To determine the existence of heterogeneity in studies, I 2 statistics and Cochran Q tests were used. The publication bias of the included studies was checked using Egger’s test and a Funnel plot. Result: A total of 2035 obstetrics care providers were involved in this systematic review and meta-analysis. The estimated overall rate of evidence-based intrapartum care practice in Ethiopia was 54.45% (95% CI: 43.06, 65.83); I 2 = 96.6%, p < 0.001). The studies with a sample size greater than 300 count for 47.25% (95% CI: 36.14, 65.83). Whereas obstetrics care providers have a decent knowledge of intrapartum care evidence 3.31 times, a positive attitude toward evidence 3.34 times, training 2.21 times, and work experience ⩾5 years 3.31 times associated with the practice of evidence-based intrapartum care. Conclusion: The overall practice of evidence-based intrapartum care among obstetrics workers in Ethiopia is estimated to be low. Therefore, there should be a focused effort on training and disseminating protocols and guidelines to enhance knowledge and foster a positive attitude among obstetrics care providers. Additionally, the Ethiopian government should prioritize the implementation of the 2021 to 2025 National Health Equity Strategic Plan to achieve its objective of improving the quality of health services
Prevalence and Associated Factors of Depression among PLHIV in Ethiopia: Systematic Review and Meta-Analysis, 2017
No full textBackground. Depression is a substantial contributor to the global burden of disease and affects people in all communities across the globe. Depression is the most common psychiatric problem associated with HIV/AIDS and half of all PLWHIV with depression go underdiagnosed and untreated. Psychiatric complications of HIVAIDS delay mental health services in less affluent countries. However, there is lack of study with regard to the pooled estimation prevalence of depression in PLWHIV in Ethiopia. Objectives. The aim of this systematic review and meta-analysis is to summarize the most current available evidence from 2010 to March 2017 among adult PLWHIV in Ethiopia. Methods. The team explored multiple databases searching methods including MEDLINE/PubMed, PsycINFO, Google Advance Scholar, and Google Scholar to find studies published with the data on the prevalence of depression among PLWHIV. We searched 150 research articles; of these 143 articles were excluded. Subsequently, thirteen articles were used for synthesis prevalence and four studies were included in the synthesis effect of sex on depression among PLWHIV. Results. The total of pooled estimated prevalence of depression in PLWHIV was 36.65. Estimated prevalence of depression in three studies by using CES-D was 31.19% and in six studies by using PHQ-9 was 37.91%. The remaining four studies used a single tool: Kessler-6 Scale (15.5%), HADS (41.2%), HDSQ (43.9%), and BDI (55.8%). Factors such as age, marital status, living alone, poor medication adherence, poor social support, clinical stages II and III of HIV, stigma, income, and occupation were significantly associated with depression. Conclusions and Recommendation. The pooled estimate prevalence of depression among PLWHIV was higher than that in the general population. It is better to offer special attention to these populations
Taguchi Method Optimization of Water Absorption Behavior by Wheat Straw-Basalt Hybrid Brake Pad Composite
No full textThe application of biomass-derived composite material is in high demand worldwide in various commercial sectors, including automotive, due to its durable, cost-effective, and environment-friendly characteristics. However, one of the limiting factors of biomass-based composites is its higher water absorption capacity compared to commercial synthetic composites. Therefore, this study aimed to optimize the water absorption capacity of biomass-based, wheat straw fiber-basalt hybrid composite brake pad using the Taguchi method by considering the particle size and volume % of the composite compositions. The composite synthesized in this study carried two variations of particle sizes of basalt, wheat straw, steel, river sand, and graphite, as well as two-volume percentages of epoxy resin for optimization. All composites were molded using a compression molding process at compressive pressure of 6 MPa for 2 h curing in a forced convection oven at 100 °C. Water absorption capacity has been determined according to ASTM D570. The wheat straw fiber has been chemically treated with 5 wt.% of sodium hydroxide (NaOH) to remove the impurities, lignin, and hemicellulose and increase the surface area of the fiber, resulting in a larger area of contact between the fiber and the matrix. Elemental analysis, crystallinity, morphology, and mechanical strength of wheat straw fiber-based composites have been determined by XRD, SEM, and compression tests, respectively. The statistical method, analysis of variance (ANOVA), was implemented for Taguchi optimization of the composite compositions. The maximum compressive strength and minimum and maximum water absorption capacity of composites were obtained as 77 MPa, 3.55%, and 26.86%, respectively. From the optimum setting of the confirmation experiment, the optimal water absorption value of 5.718% has been obtained. The optimum particle size of the composite compositions was 1 mm basalt particle, 0.5 mm wheat straw fiber, 1 mm steel particle, 1 mm river sand, 0.5 mm graphite dust particle, and 30 vol% epoxy resin by Taguchi method. The parameter impact of Taguchi ranking on water absorption capacity presented the maximum improvement of water absorption, 10.47%, with river sand particle size
Chemical Composition and Extraction of Micro Crystalline Cellulose from Outer Skin Isolated Coffee Husk
No full textCoffee husk (CH) is a sustainable and abundantly available cellulosic waste material. Its fiber consists of cellulose as the major structural part which leads to potential utilization for the manufacturing of microcrystalline cellulose (MCC) products that can be utilized for different industrial applications. In the present study, chemical composition of outer skin-isolated coffee husk was determined and sequential treatments of various untreated (UT) sample, ethanol—toluene treated sample through dewaxed (DW) treatment, sodium hydroxide (NaOH)—treated sample through alkali (AT) treatment, and sulfuric acid (H2SO4)—treated sample through bleaching (BL) treatment have been carried out. The Micro Crystalline Cellulose (MCC) has been extracted through hydrogen peroxide (H2O2) after BL treatment. The BL treatment for MCC extraction process was conducted without chlorine and additional harsh acid treatment, respectively. The characterization of chemically treated samples was carried out to investigate their morphological, physico-chemistry, and thermal behavior through a scanning electron microscope (SEM), Fourier transform infrared—ray (FTIR), X-ray diffraction (XRD), thermo gravimetric analysis (TGA), and differential temperature analyzer (DTA). From the chemical composition analysis; the cellulose, hemicellulose, lignin, and extractive content were determined and its values were (52.9%), (12.5%), (24.3%), and (9.4%), respectively. In the morphological examination, the great untreated (UT) fiber sample was greatly reduced into a micro-sized BL sample, revealing that (from FTIR analysis) the lignin and hemicellulose contents were greatly removed during chemical treatments and the presence of a micro crystalline cellulose region with 54.7% yield. Also, the sample AT and BL showed the lowest amorphous region in X-RD due to the removal of hemicellulose and lignin. The highest crystallinity index has been determined for the BL sample, i.e., 89.9%. Additionally, the thermal analysis shows that the AT and BL sample has great thermal stability than other (UT and DW) samples at high temperature. Therefore, the outer skin separated coffee husk was prepared from agricultural waste was subjected to eco-friendly chemical treatments to yield MCC. Thus, the extracted MCC is expected to be reliable for replacing other plant materials for the production of crystalline nanomaterial and reinforcing constituent for the fabrication of bio composite
Regulatory tradeoffs in designing concession contracts for infrastructure networks
No full textNetwork activities typically involve collecting a good or service (such as electric utilities, phone services, and rail transportation) from many producers or distributing them to many users. Producers and users are often widely scattered, geographically. Close financial integration of networks is justified on the basis of economies of scope and scale and the benefits from pooling and coordinating. In many countries, network operators are completely integrated publicly-owned firms (private firms being deemed insufficiently efficient or equitable). Challengers of this practice contend that the inefficiency resulting from lack of competition outweighs the gain from economic integration. With reform, some competitive mechanisms can be introduced even when monopoly seems the best option for delivering a service. But conflicts between policymakers'objectives -including efficiency, equity, speed, speed of reform, and signaling- influence the design of concession contracts for infrastructure network services (including communications and transportation services). Competition begins with the unbundling of various stages of delivery. Then competitive bidding is popular, with the public authority keeping property rights on productive assets but conceding their operation to a private firm. The winner gets the right to maximize profits, within limits (having to provide universal services, for example, and avoid price discrimination). In liberalizing the delivery of a service, policymakers must consider not only efficiency but also social and fiscal feasibility. The authors discuss how relevant information asymmetry is in contract design and the award and regulatory processes. They also discuss how to design pricing to accommodate the obligation to provide universal service. To illustrate, they describe Argentina's experiment in liberalization, which is increasingly viewed as a model for changing private sector and government involvement in infrastructure services. Beginning in 1989, Argentina began privatizing utilities and transport services, because the government had decided that it could no longer afford to subsidize those services or finance the investments needed for their effective operation. To introduce competition, the government unbundled services and introduced competitive bidding. It also created sector-specific regulatory agencies to protect consumers from private monopolies and to protect the private concessionaires from government micromanagement. Making concession-based reform and contracted-based regulation of private monopolists sustainable will require strengthening regulatory agencies, clarifying their terms of reference and accountability, and better separating the responsibilities of sector ministers and regulators.Health Economics&Finance,Environmental Economics&Policies,Economic Theory&Research,Labor Policies,International Terrorism&Counterterrorism,Environmental Economics&Policies,Health Economics&Finance,Education for the Knowledge Economy,Knowledge Economy,Economic Theory&Research
Demographic observations of mountain nyala Tragelaphus buxtoni in a controlled hunting area, Ethiopia
No full textThe highlands of Ethiopia are inhabited by the culturally and economically significant mountain nyala Tragelaphus buxtoni, an endemic spiral horned antelope. The natural range of this species has become highly fragmented with increasing anthropogenic pressures; driving land conversion in areas previously considered critical mountain nyala habitat. Therefore, baseline demographic data on this species throughout its existing range are needed. Previous studies on mountain nyala demographics have primarily focused on a confined portion of its known range where trophy hunting is not practiced. Our objectives were to estimate group size, proportion of females, age class proportions, and calf and juvenile productivity for a sub-population of mountain nyala where trophy hunting is permitted and compare our results to recent and historical observations. We collected four years of demographic data using direct point counts in a controlled hunting area and summarized the data using the R statistical software. Our results show that estimated proportion of females (0.63; 0.56-0.69) was similar to recent studies of non-hunted populations, but group size (3.74; 3.34-4.13), juvenile productivity (0.47; 0.35-0.62) and age class proportions (calves: 0.17 juveniles: 0.19 adults: 0.64) were considerably different. Our results are more similar to historical accounts than those in a national park. We demonstrate that the mountain nyala's population structure and health varies across its range and may relate to the different management strategies and policies. We recommend using similar methods for remaining under surveyed sub-populations of mountain nyala to inform conservation actions at the landscape scale
Physical and mechanical behavior of aluminum-magnesium alloy matrix hybrid composite fabricated through friction stir consolidation process
No full textNowadays metal matrix composite materials are preferable in automotive and aerospace industries due to their mechanical properties and essentially attractive strength to weight ratios. However, their availability in use is limited because of their manufacturing method difficulty and process extravagancy. The aim of this research was to fabricate metal matrix hybrid composite through a novel approach thermo-mechanical method called friction stir consolidation (FSC) process. XRD result witnessed the presence of SiC, ZrO 2 , and AZ61 alloy phases. Different compositions of AZ61, SiC, and ZrO 2 powder were taken into consideration and the progression of the FSC process were examined through properties of compressive strength, hardness, density, and porosity. For instance, the compressive yield strength of composition 85%Vol. of AZ61, 10%Vol. of ZrO 2 , and 5%Vol. of SiC accounts 164.2 MPa with an acceptable 2.2451 g/cm 3 and 0.593% density and porosity respectively. However, when the strength to weight ratio was taken into consideration, 95%Vol. of AZ61, 2.5%Vol. of ZrO 2 , and 2.5%Vol. of SiC composition attained highest strength to weight ratio value. Additionally, the compressive yield strength value increased directly proportional with the ZrO 2 volumetric composition. Likewise, the fractured surface of sample acquired highest strength to weight ratio was examined through SEM Fractography analysis
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