537 research outputs found

    Renewable electricity generation and transmission network developments in light of public opposition: Insights from Ireland. ESRI Working Paper No. 653 March 2020

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    This paper analyses how people’s attitudes towards onshore wind power and overhead transmission lines affect the costoptimal development of electricity generation mixes, under a high renewable energy policy. For that purpose, we use a power systems generation and transmission expansion planning model, combined with information on public attitudes towards energy infrastructure on the island of Ireland. Overall, households have a positive attitude towards onshore wind power but their willingness to accept wind farms near their homes tends to be low. Opposition to overhead transmission lines is even greater. This can lead to a substantial increase in the costs of expanding the power system. In the Irish case, costs escalate by more than 4.3% when public opposition is factored into the constrained optimisation of power generation and grid expansion planning across the island. This is mainly driven by the compounded effects of higher capacity investments in more expensive technologies such as offshore wind and solar photovoltaic to compensate for lower levels of onshore wind generation and grid reinforcements. The results also reveal the effect of public opposition on the value of onshore wind, via shadow prices. The higher the level of public opposition, the higher the shadow value of onshore wind. And, this starkly differs across regions: regions with more wind resource or closest to major demand centres have the highest shadow prices. The shadow costs can guide policy makers when designing incentive mechanisms to garner public support for onshore wind installations

    ANALISIS PENYEBAB HANCURNYA FORCED DRAFT FAN TERHADAP UDARA PEMBAKARAN AUXILIARY BOILER DI KAPAL MT. SEPINGGAN

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    ABSTRAK Desta Alimasoni Febriantoro, 2019, “Analisis Penyebab Hancurnya Forced Draft Fan Terhadap Udara Pembakaran Auxiliary Boiler Di Kapal MT. Sepinggan”. Skripsi, Teknika Program Diploma IV PIP Semarang. Pembimbing: (I) Dr. Eko Nugroho Widjatmoko,MM,Mar. (II) Budi Joko Raharjo, M.M. Kapal-kapal pengangkut bahan bakar minyak (oil product tanker) yang masih menggunakan ketel uap sebagai pesawat bantu, untuk menggerakan turbin uap, windlass dan sebagai pemanas bahan bakar serta kebutuhan lainnya untuk menunjang beroperasinya kapal, instalasi ketel uap penghasil uap bertekanan tidak terlepas dari yang namanya forced draft fan. Pada instalasi ketel uap, forced draft fan berfungsi untuk menghasilkan udara pembakaran dengan debit udara yang sangat besar. Kerusakan yang terjadi pada forced draft fan auxiliaray boiler yaitu hancurnya impeller fan dan kerusakan pada electromotor serta scrool casing yang diakibatkan karena beberapa faktor. Sehingga menyebabkan auxiliary boiler tidak dapat dioperasikan karena tidak ada pasokan udara pembakaran yang dihasilkan forced draft fan. Tujuan penelitian ini adalah untuk mengetahui pengaruh ball bearing electromotor, air damper pada suction cone dan windbox. Metode yang digunakan adalah deskriptif kualitatif, dengan menjelaskan secara spesifik gambaran tentang forced draft fan auxiliary boiler, dan teknik analisis yang digunakan pada penelitian ini menggunakan urgency, seriousness, growth (USG) penilaian prioritas masalah. Setelah dilakukan penilaian prioritas masalah, kemudian dilakukan pengamatan permasalahn menggunakan Teknik analisis software, hardware, environment, liveware (SHEL). Hasil penelitian yang dilakukan pada permasalahan ini adalah kerusakan pada komponen ball bearing electromotor penggerak impeller fan yang harus diganti karena tidak dapat dilakukan perbaikan. Pengaruh pengaturan air damper pada suction cone dan windbox terhadap nyala api dalam auxiliary boiler karena debit udara pembakaran yang dihasilkan dan beban yang diterima electromotor untuk menggerakkan impeller fan karena udara yang dihasilkan tertahan didalam windbox oleh air damper. ABSTRACT Desta Alimasoni Febriantoro, 2019, “Analysis The Causes of Destruction of the Forced Draft Fan Towards Air Combustion Auxiliary Boiler on the vessel MT. Sepinggan”. Final Project, Technical Department Diploma IV Program PIP Semarang. Advisory by: (I) Dr. Eko Nugroho Widjatmoko,MM,Mar. (II) Budi Joko Raharjo, M.M. Oil fuel tankers (oil product tankers) that still use steam boilers as auxiliary engine, to drive steam turbines, windshields and fuel heaters as well. They support the operation of the ship, the gas-producing boiler installation was forced to drive the fan. In a steam boiler installation, forced draft fan functions to produce combustion air with very large air discharge. The damage that occured in the forced draft fan auxiliary boiler was the destruction of the fan impeller and damage of the electromotor and the casing scroll caused by several factors. So that the auxiliary boiler couldn’t be operated due to there was no supply of combustion air produced by forced draft fan. The purpose of this study was to determine the effect of electromotor ball bearings, air dampers on the suction cone and wind box. The method used was descriptive qualitative, by explaining the description of the forced draft fan auxiliary boiler specifically, and the analysis technique used in this study using urgency, seriousness, growth (USG) to assess the priority of the problems. After evaluating the priority of the problems, then for collecting data by observation and interview. And analysis software, hardware, environment, liveware (SHEL) techniques was used to observe the causes of destruction of forced draft fan. The results of the research showed that the damage of the components of the ball bearing electromotor drive impeller fan which must be replaced because it cannot be repaired. The effect of the water damper setting on the suction cone and wind box on the flame in the auxiliary boiler because of the combustion air produced and the load received by the electromotor to drive the fan impeller due to the air produced was held in the wind box by the damper water

    Population pharmacogenetic-based pharmacokinetic modeling of efavirenz, 7-hydroxy- and 8-hydroxyefavirenz

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    The purpose of this study was to determine the demographic and pharmacogenetic covariates that influence the disposition of efavirenz (EFV) and its major metabolites. A population pharmacokinetic (PK) model was developed from a randomized, cross-over, drug-interaction study in healthy male Korean subjects (n = 17). Plasma concentrations of EFV and its hydroxy-metabolites (0-120 hours) were measured by LC/MS/MS. Genomic DNA was genotyped for variants in the cytochrome P450 (CYP) 2A6, 2B6, 3A5, and MDR1 genes. A PK model was built in a stepwise procedure using nonlinear mixed effect modeling in NONMEM 7. The covariate model was built using the generalized additive modeling and forward selection-backward elimination. Model-based simulations were performed to predict EFV steady-state concentrations following 200, 400, and 600 mg daily oral dose among different CYP2B6 genotypes. The final model included only CYP2B6 genotype as a covariate that predicts EFV clearance through the formation of 8-OH EFV that represented 65% to 80% of EFV clearance. The total clearance of EFV in CYP2B6*6/*6 genotype was ∼30% lower than CYP2B6*1/*1 or CYP2B6*1/*6 alleles (P < .001). Clopidogrel reduced both formation and elimination clearances of 8-OH EFV by 22% and 19%, respectively (P = .033 and .041). Other demographics and genotype of accessory CYP pathways did not predict EFV or metabolites PK. CYP2B6 genotype was the only significant predictor of EFV disposition. The developed model may serve as the foundation for further exploration of pharmacogenetic-based dosing of EFV

    Podoconiosis and soil-transmitted helminths (STHs): double burden of neglected tropical diseases in Wolaita zone, rural southern Ethiopia

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    Background Both podoconiosis and soil-transmitted helminth (STH) infections occur among barefoot people in areas of extreme poverty; however, their co-morbidity has not previously been investigated. We explored the overlap of STH infection and podoconiosis in Southern Ethiopia and quantified their separate and combined effects on prevalent anemia and hemoglobin levels in podoconiosis patients and health controls from the same area. Methods and Principal Findings A two-part comparative cross-sectional study was conducted in Wolaita zone, southern Ethiopia. Data were collected from adult patients presenting with clinically confirmed podoconiosis, and unmatched adult neighborhood controls living in the same administrative area. Information on demographic and selected lifestyle factors was collected using interviewer-administered questionnaires. Stool samples were collected and examined qualitatively using the modified formalin-ether sedimentation method. Hemoglobin level was determined using two different methods: hemoglobinometer and automated hematology analyzer. A total of 913 study subjects (677 podoconiosis patients and 236 controls) participated. The prevalence of any STH infection was 47.6% among patients and 33.1% among controls (p<0.001). The prevalence of both hookworm and Trichuris trichiura infections was significantly higher in podoconiosis patients than in controls (AOR 1.74, 95% CI 1.25 to2.42, AOR 6.53, 95% CI 2.34 to 18.22, respectively). Not wearing shoes and being a farmer remained significant independent predictors of infection with any STH. There was a significant interaction between STH infection and podoconiosis on reduction of hemoglobin level (interaction p value = 0.002). Conclusions Prevalence of any STH and hookworm infection was higher among podoconiosis patients than among controls. A significant reduction in hemoglobin level was observed among podoconiosis patients co-infected with hookworm and ‘non-hookworm STH’. Promotion of consistent shoe-wearing practices may have double advantages in controlling both podoconiosis and hookworm infection in the study area

    Community-based control of a neglected tropical disease: the mossy foot treatment and prevention association

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    Podoconiosis (endemic non-filarial elephantiasis, also known as mossy foot) is a non-communicable disease now found exclusively in the tropics, caused by the conjunction of environmental, genetic, and economic factors. Silicate particles formed by the disintegration of lava in areas of high altitude (over 1,000 m) and seasonal rainfall (over 1,000 mm per annum) penetrate the skin of barefoot subsistence farmers, and in susceptible individuals cause lymphatic blockage and subsequent elephantiasis [1]. Although an estimated one million Ethiopians (of a total population of 77 million) are afflicted with podoconiosis [2], which creates a huge economic burden in endemic areas [3], no national policy has yet been developed to control or prevent the condition, and most affected communities remain unaware of treatment options

    Podoconiosis in East and West Gojam Zones, Northern Ethiopia

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    Background: Podoconiosis is a neglected tropical disease (NTD) that is prevalent in red clay soil-covered highlands of tropical Africa, Central and South America, and northern India. It is estimated that up to one million cases exist in Ethiopia. This study aimed to estimate the prevalence of podoconiosis in East and West Gojam Zones of Amhara Region in northern Ethiopia. Methodology/Principal Findings: A cross-sectional household survey was conducted in Debre Eliyas and Dembecha woredas (districts) in East and West Gojam Zones, respectively. The survey covered all 17,553 households in 20 kebeles (administrative subunits) randomly selected from the two woredas. A detailed structured interview was conducted on 1,704 cases of podoconiosis identified in the survey. Results: The prevalence of podoconiosis in the population aged 15 years and above was found to be 3.3% (95% CI, 3.2% to 3.6%). 87% of cases were in the economically active age group (15–64 years). On average, patients sought treatment five years after the start of the leg swelling. Most subjects had second (42.7%) or third (36.1%) clinical stage disease, 97.9% had mossy lesions, and 53% had open wounds. On average, patients had five episodes of acute adenolymphangitis (ALA) per year and spent a total of 90 days per year with ALA. The median age of first use of shoes and socks were 22 and 23 years, respectively. More men than women owned more than one pair of shoes (61.1% vs. 50.5%; x2 = 11.6 p = 0.001). At the time of interview, 23.6% of the respondents were barefoot, of whom about two-thirds were women. Conclusions: This study showed high prevalence of podoconiosis and associated morbidities such as ALA, mossy lesions and open wounds in northern Ethiopia. Predominance of cases at early clinical stage of podoconiosis indicates the potential for reversing the swelling and calls for disease prevention interventions

    Prevalence and predictors of uterine rupture among Ethiopian women: A systematic review and meta-analysis.

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    BackgroundUterine rupture has a significant public health importance, contributing to 13% of maternal mortality and 74%-92% of perinatal mortality in Sub-Saharan Africa, and 36% of maternal mortality in Ethiopia. The prevalence and predictors of uterine rupture were highly variable and inconclusive across studies in the country. Therefore, this systematic review and meta-analysis aimed to estimate the pooled prevalence and predictor of uterine rupture in Ethiopia.MethodsThis systematic review and meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2009 checklist. PubMed, Cochrane Library, Google Scholar, and African Journals Online databases were searched. The Newcastle- Ottawa quality assessment tool was used for critical appraisal. I2 statistic and Egger's tests were used to assess the heterogeneity and publication bias, respectively. The random-effects model was used to estimate the pooled prevalence and odds ratios with a 95% confidence interval.ResultsSixteen studies were included, with a total of 91,784 women in the meta-analysis. The pooled prevalence of uterine rupture was 2% (95% CI: 1.99, 3.01). The highest prevalence was observed in the Amhara regional state (5%) and the lowest was in Tigray region (1%). Previous cesarean delivery (OR = 9.95, 95% CI: 3.09, 32.0), lack of antenatal care visit (OR = 8.40, 95% CI: 4.5, 15.7), rural residence (OR = 4.75, 95% CI: 1.17, 19.3), grand multiparity (OR = 4.49, 95% CI: 2.83, 7.11) and obstructed labor (OR = 6.75, 95%CI: 1.92, 23.8) were predictors of uterine rupture.ConclusionUterine rupture is still high in Ethiopia. Therefore, proper auditing on the appropriateness of cesarean section and proper labor monitoring, improving antenatal care visit, and birth preparedness and complication readiness plan are needed. Moreover, early referral and family planning utilization are the recommended interventions to reduce the burden of uterine rupture among Ethiopia women

    Influence of Battery Energy Storage Systems on Transmission Grid Operation With a Significant Share of Variable Renewable Energy

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    The generation mix of Portugal now contains a significant amount of variable renewable energy sources (RES) and the amount of RES is expected to grow substantially. This has led to concerns being raised regarding the security of the supply of the Portuguese electric system as well as concerns relating to system inertia. Deploying and efficiently using various flexibility options is proposed as a solution to these concerns. Among these flexibility options proposed is the use of battery energy storage systems (BESSs) as well as relaxing system inertia constraints such as the system nonsynchronous penetration (SNSP). This article proposes a stochastic mixed-integer linear programming problem formulation, which examines the effects of deploying BESS in a power system. The model is deployed on a real-world test case and results show that the optimal use of BESS can reduce system costs by as much as 10% relative to a baseline scenario and the costs are reduced further when the SNSP constraint is relaxed. The amount of RES curtailment is also reduced with the increased flexibility of the power system through the use of BESS. Thus, the efficiency of the Portuguese transmission system is greatly increased by the use of flexibility measures, primarily the use of BESS.©2021 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.fi=vertaisarvioitu|en=peerReviewed
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