Search results for: hinge replacement

Authors: Avdasheva Svetlanaa, Kryuchkova Polinab

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Comparative social efficiency of private and public enforcement of law is debated. This question is not of academic interest only, it is also important for the development of the legal system and regulations. Generally, involvement of ‘common citizens’ in public law enforcement is considered to be beneficial, while involvement of interest groups representatives is not. Institutional economics as well as law and economics consider the difference between public and private enforcement to be rather mechanical. Actions of bureaucrats in government agencies are assumed to be driven by the incentives linked to social welfare (or other indicator of public interest) and their own benefits. In contrast, actions of participants in private enforcement are driven by their private benefits. However administrative law enforcement may be designed in such a way that it would become driven mainly by individual incentives of alleged victims. We refer to this system as reactive public enforcement. Citizens may prefer using reactive public enforcement even if private enforcement is available. However replacement of public enforcement by reactive version of public enforcement negatively affects deterrence and reduces social welfare. We illustrate the problem of private vs pure public and private vs reactive public enforcement models with the examples of three legislation subsystems in Russia – labor law, consumer protection law and competition law. While development of private enforcement instead of public (especially in reactive public model) is desirable, replacement of both public and private enforcement by reactive model is definitely not.

Keywords: public enforcement, private complaints, legal errors, competition protection, labor law, competition law, russia

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Authors: Carlos Joel Tchawouo Mbiada

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At the back of the apartheid era, South Africa embarked on a democratic drive of all its institution underpinned by a social justice perspective to eradicate past injustices. These democratic values based on fundamental human rights and equality informed all rights enshrined in the Constitution of the Republic of South Africa, 1996. This means that all rights are therefore infused by social justice perspective and labour rights are no exception. Labour law is therefore regulated to the extent that it is viewed as too rigid. Hence a call for more flexibility to enhance investment and boost job creation. This view articulated by the Free Market Foundation fell on deaf ears as the opponents believe in what is termed regulated flexibility which affords greater protection to vulnerable workers while promoting business opportunities and investment. The question that this paper seeks to examine is to what extent the regulation of labour law will go to protect employees. This question is prompted by the recent Constitutional Court’s judgment of National Union of Metalworkers of South Africa v Trenstar which barred the employer from employing labour replacement in response to the strike action by its employees. The question whether employers may use replacement labour and have recourse to lock-outs in response to strike action is considered in the context of the dichotomy between the Free market foundation and social justice perspectives which are at loggerheads in the South African collective bargaining process. With the current unemployment rate soaring constantly, the aftermath of the Covid 19 pandemic, the effects of the war in Ukraine and lately the financial burden of load shedding on companies to run their businesses, this paper argues for a policy shift toward deregulation or a lesser state and judiciary intervention. This initiative will relieve the burden on companies to run a viable business while at the same time protecting existing jobs.

Keywords: labour law, replacement labour, right to strike, free market foundation perspective, social justice perspective

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Authors: Do-Kyu Hwang, Ho-Young Kim, Ho-Hyeoung Choi, Gi-Beom Park, Jae-Hoon Lee

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Currently there are many use of threaded reinforcing bars in construction fields because those do not need additional screw processing when connecting reinforcing bar by threaded coupler. In this study, reinforced concrete bridge piers using threaded rebar coupler system at the plastic hinge area were tested to evaluate seismic performance. The test results showed that threads of the threaded rebar coupler system could be loosened while under tension-compression cyclic loading because tolerance and rib face angle of a threaded rebar coupler system are greater than that of a conventional ribbed rebar coupler system. As a result, cracks were concentrated just outside of the mechanical coupler and stiffness of reinforced concrete bridge pier decreased. Therefore, it is recommended that connection ratio of mechanical couplers in one section shall be below 50% in order that cracks are not concentrated just outside of the mechanical coupler. Also, reduced stiffness of the specimen should be considered when using the threaded rebar coupler system.

Keywords: reinforced concrete column, seismic performance, threaded rebar coupler, threaded reinforcing bar

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Authors: Joana Gato, Ahmed Abotabekh, Panayoti Bachkangi

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Introduction: Oestrogen is an essential gonadal hormone that plays a vital role in the reproductive system of women1. The average age of menopause in the UK is 512. Women who go through premature menopause should be offered Hormone replacement therapy (HRT). Similarly, women who undergo surgical menopause should be offered HRT, unless contraindicated, depending on the indication of their surgery2,3. Aim: To assess if the patients in our department are counselled regarding HRT after surgical treatment and if HRT was prescribed. Methodology: A retrospective audit in a busy district hospital, examining all the patients who had a hysterectomy. The audit examined if HRT was discussed pre-operatively, prescribed on discharge and if a follow up was arranged. For women with contraindication to HRT, the audit assessed if the reasons were discussed pre-operatively and communicated to the Inclusion criteria: woman having a total or subtotal hysterectomy, with or without bilateral salpingo-ophorectomy (BSO), between April and September 2022. Exclusion criteria: woman having a vaginal hysterectomy. Results: 40 patients in total had hysterectomy; 27 (68%) were under the age of 51. 15 out of 27 patients bad BSO. 9 women were prescribed HRT, but 8 were offered HRT immediately, and 1 of them were offered a follow up. Of women who underwent surgical menopause, 7 were not given any HRT. The HRT choice was diverse, however, the majority was prescribed oral HRT. 40% of women undergoing surgical menopause did not have a discussion about HRT prior to their surgery. In postmenopausal women (n=13; 33%), still two were given HRT for preexisting menopausal symptoms. Discussion: Only 59% of the pre-menopausal patients had oophorectomy, therefore undergoing surgical menopause. Of these, 44% were not given any HRT, and 40% had no discussion about HRT prior to surgery. Interestingly, the majority of these women have no obvious contraindication to HRT. The choice of HRT was diverse, but the majority was commenced on oral HRT. Our unit is still working towards meeting all the NICE guidance standards of offering HRT and information prior to surgery to women planning to undergo surgical menopause. Conclusion: Starting HRT at the onset of menopause has been shown to improve quality of life and reduce the risk of cardiovascular disease and osteoporotic fractures4. Our unit still has scope for improvement to comply with the current NICE guidance. All pre-menopausal women undergoing surgical menopause should have a discussion regarding HRT prior to surgery and be offered it if there are no contraindications. This discussion should be clearly documented in the notes. At the time of this report, some of the patients have not yet had a follow up, which we recognize as a limitation to our audit.

Keywords: hormone replacement therapy, menopause, premature ovarian insufficiency, surgical management

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Authors: Chaiyakrit Raoupatham, Ram Hari Dhakal, Chalermchai Wanichlamlert

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Fresh concrete that is on bound to be rejected due to belated use either from delay construction process or unflavored traffic cause delay on concrete delivering can recover the slump and use once again by introduce second dose of superplasticizer(naphthalene based type F) into system. By adding superplasticizer as solution for recover unusable slump loss concrete may affects other concrete properties. Therefore, this paper was observed setting time and compressive strength of concrete after being re-dose with chemical admixture type F (superplasticizer, naphthalene based) for slump recovery. The concrete used in this study was fly ash concrete with fly ash replacement of 0%, 30% and 50% respectively. Concrete mix designed for test specimen was prepared with paste content (ratio of volume of cement to volume of void in the aggregate) of 1.2 and 1.3, water-to-binder ratio (w/b) range of 0.3 to 0.58, initial dose of superplasticizer (SP) range from 0.5 to 1.6%. The setting time of concrete were tested both before and after re-dosed with different amount of second dose and time of dosing. The research was concluded that addition of second dose of superplasticizer would increase both initial and final setting times accordingly to dosage of addition. As for fly ash concrete, the prolongation effect was higher as the replacement of fly ash is increase. The prolongation effect can reach up to maximum about 4 hours. In case of compressive strength, the re-dosed concrete has strength fluctuation within acceptable range of ±10%.

Keywords: compressive strength, fly ash concrete, second dose of superplasticizer, setting times

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Authors: C. C. Okafor, T. M. Ezeh

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The effect of addition of sweet potato leaves in replacement of wheat offal in the production of broiler chicks feed was studied. 72 day-old marshal strain chicks were used and brooded for two weeks with a normal commercial feed in Nigeria called top feed and weighed separately at the end of the two weeks, complete randomized design (CRD) was used. The weighed broiler chicks were randomly allocated to four dietary treatments. Each treatment was replicated to twice with eighteen birds per replicate. The four dietary treatment identified as T1, T2, T3 and T4. T1 served as control diet with 21% crude protein content, while T2 was prepared with Enzyme and in T3 and T4, wheat offal was replaced with sweet potato leaves and in T4 with inclusion of enzyme. Growth performance was studied using the following daily feed intake, daily weight gain and feed efficiency. The result in daily weight gain showed that chicks fed with T2 feed had the highest weight gain (93.75) while chicks fed with T3 had the least weight gain of (34.5 gm). In daily feed intake chicks fed with T4 fed more (53.06 gm) than chicks fed with T2 (51.08 gm). In feed efficiency T3 had the highest value of 30% while the T2 had the least efficiency of 22%. There was no significant difference (P≥ 0.05) in all the three parameter tested. Sweet potato leaves can replace wheat offal in broiler feed production without any adverse effect on the growth performance.

Keywords: broiler, diet, dietary, potato leaves, wheat offal

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Authors: Yingkun Huang, Li Guo, Zekang Lan, Kai Tian

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Hard disk drives (HDD) failure of the exascale supercomputing system may lead to service interruption and invalidate previous calculations, and it will cause permanent data loss. Therefore, initiating corrective actions before hard drive failures materialize is critical to the continued operation of jobs. In this paper, a highly accurate analysis model based on CNN-LSTM and oversampling technique was proposed, which can correctly predict the necessity of a disk replacement even ten days in advance. Generally, the learning-based method performs poorly on a training dataset with long-tail distribution, especially fault prediction is a very classic situation as the scarcity of failure data. To overcome the puzzle, a new oversampling was employed to augment the data, and then, an improved CNN-LSTM with the shortcut was built to learn more effective features. The shortcut transmits the results of the previous layer of CNN and is used as the input of the LSTM model after weighted fusion with the output of the next layer. Finally, a detailed, empirical comparison of 6 prediction methods is presented and discussed on a public dataset for evaluation. The experiments indicate that the proposed method predicts disk failure with 0.91 Precision, 0.91 Recall, 0.91 F-measure, and 0.90 MCC for 10 days prediction horizon. Thus, the proposed algorithm is an efficient algorithm for predicting HDD failure in supercomputing.

Keywords: HDD replacement, failure, CNN-LSTM, oversampling, prediction

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Authors: Goksen Capar, Levent Dogankaya

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According to the circular economy model, resource productivity should be maximized and wastes should be reduced. Since earth’s natural resources are continuously depleted, resource recovery has gained great interest in recent years. As part of our research study on the recovery and reuse of silk wastes, this paper focuses on the utilization of silkworm pupae as fishmeal replacement, which would replace the original fishmeal raw material, namely the fish itself. This, in turn, would contribute to sustainable management of wild fish resources. Silk fibre is secreted by the silkworm Bombyx mori in order to construct a 'room' for itself during its transformation process from pupae to an adult moth. When the cocoons are boiled in hot water, silk fibre becomes loose and the silk yarn is produced by combining thin silk fibres. The remaining wastes are 1) sericin protein, which is dissolved in water, 2) remaining part of cocoon, including the dead body of B. mori pupae. In this study, an eight weeks trial was carried out to determine the growth performance of common carp juveniles fed with waste silkworm pupae meal (SWPM) as a replacement for fishmeal (FM). Four isonitrogenous diets (40% CP) were prepared replacing 0%, 33%, 50%, and 100% of the dietary FM with non-defatted silkworm pupae meal as a dietary protein source for experiments in C. carpio. Triplicate groups comprising of 20 fish (0.92±0.29 g) were fed twice/day with one of the four diets. Over a period of 8 weeks, results showed that the diet containing 50% of its protein from SWPM had significantly higher (p ≤ 0.05) growth rates in all groups. The increasing levels of SWPM were resulted in a decrease in growth performance and significantly lower growth (p ≤ 0.05) was observed with diets having 100% SWPM. The study demonstrates that it is practical to replace 50% of the FM protein with SWPM with a significantly better utilization of the diet but higher SWPM levels are not recommended for juvenile carp. Further experiments are under study to have more detailed results on the possible effects of this alternative diet on the growth performance of juvenile carp.

Keywords: Bombyx mori, Cyprinus carpio, fish meal, silk, waste pupae

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Authors: Leonor Varandas, Pedro D. Gaspar, Martim L. Aguiar

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One of the biggest concerns in the field of agriculture is around the energy efficiency of robots that will perform agriculture’s activity and their charging methods. In this paper, two different charging methods for agricultural standalone docking stations are shown that will take into account various variants as field size and its irregularities, work’s nature to which the robot will perform, deadlines that have to be respected, among others. Its features also are dependent on the orchard, season, battery type and its technical specifications and cost. First charging base method focuses on wireless charging, presenting more benefits for small field. The second charging base method relies on battery replacement being more suitable for large fields, thus avoiding the robot stop for recharge. Existing many methods to charge a battery, the CC CV was considered the most appropriate for either simplicity or effectiveness. The choice of the battery for agricultural purposes is if most importance. While the most common battery used is Li-ion battery, this study also discusses the use of graphene-based new type of batteries with 45% over capacity to the Li-ion one. A Battery Management Systems (BMS) is applied for battery balancing. All these approaches combined showed to be a promising method to improve a lot of technical agricultural work, not just in terms of plantation and harvesting but also about every technique to prevent harmful events like plagues and weeds or even to reduce crop time and cost.

Keywords: agricultural mobile robot, charging methods, battery replacement method, wireless charging method

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Authors: Pei-Ru Yang, Yu-Chen Lin, Jia-Min Wu

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Background: A 58-year-old man with a history of osteoporosis and diabetes presented with chronic pain in his left knee due to severe knee joint degeneration. The knee replacement surgery was recommended by the doctor. But the patient suffered from low pain tolerance and wondered if virtual reality could relieve acute postoperative wound pain. Methods: We used the PICO (patient, intervention, comparison, and outcome) approach to generate indexed keywords and searched systematic review articles from 2017 to 2021 on the Cochran Library, PubMed, and Clinical Key databases. Results: The initial literature results included 38 articles, including 12 Cochrane library articles and 26 PubMed articles. One article was selected for further analysis after removing duplicates and off-topic articles. The eight trials included in this article were published between 2013 and 2019 and recruited a total of 723 participants. The studies, conducted in India, Lebanon, Iran, South Korea, Spain, and China, included adults who underwent hemorrhoidectomy, dental surgery, craniotomy or spine surgery, episiotomy repair, and knee surgery, with a mean age (24.1 ± 4.1 to 73.3 ± 6.5). Virtual reality is an emerging non-drug postoperative analgesia method. The findings showed that pain control was reduced by a mean of 1.48 points (95% CI: -2.02 to -0.95, p-value < 0.0001) in minor surgery and 0.32 points in major surgery (95% CI: -0.53 to -0.11, p-value < 0.03), and the overall postoperative satisfaction has improved. Discussion: Postoperative pain is a common clinical problem in surgical patients. Research has confirmed that virtual reality can create an immersive interactive environment, communicate with patients, and effectively relieve postoperative pain. However, virtual reality requires the purchase of hardware and software and other related computer equipment, and its high cost is a disadvantage. We selected the best literature based on clinical questions to answer the patient's question and used share decision making (SDM) to help the patient make decisions based on the clinical situation after knee replacement surgery to improve the quality of patient-centered care.

Keywords: knee replacement surgery, postoperative pain, share decision making, virtual reality

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Authors: Kunjie Fan

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Fly ash has been widely used as supplemental cementitious material in concrete for decades, especially in the ready-mixed concrete industry. Addition of fly ash not only brings economic and environmental benefits but also improves the engineering properties of concrete. It is well known that the pre-fire load has significant impacts on mechanical properties of concrete at high temperatures, however, the fire performance of stressed fly ash concrete is still not clear. Therefore, an apparatus was specially designed for testing “hot” mechanical properties of fly ash concrete with different heating-loading regimes. Through the experimental research, the mechanical properties, including compressive strength, peak strain, elastic modulus, complete stress-strain relationship, and transient thermal creep of fly ash concrete under uniaxial compression at elevated temperatures, have been investigated. It was found that the compressive strength and the elastic modulus increase with the load level, while the peak strain decreases with the applied stress level. In addition, 25% replacement of OPC with FA in the concrete mitigated the deterioration of the compressive strength, the development of transient thermal creep, and the nonlinearity of stress-strain response at elevated temperatures but hardly influenced the value of the elastic modulus and the peak strain. The applicability of Eurocode EN1992-1-2 to normal strength concrete with 25% replacement of fly ash has been verified to be safe. Based on the experimental analysis, an advanced constitutive model for stressed fly ash concrete at high temperatures was proposed.

Keywords: fire performance, fly ash concrete, pre-fire load, mechanical properties, transient thermal creep

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Authors: Jungkyun Na, Jaesang Lee, Yang Mo Koo

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In this study to find a replacement for expensive secondary recrystallization in GO electrical steel production, effect of heat treatment on the formation of columnar grain and Goss texture is investigated. The composition of the sample is Fe-2.0Si-0.2C. This process involves repeating of cold rolling and decarburization as a replacement for secondary recrystallization. By cold-rolling shear band is made and Goss grain grows from shear band by decarburization. By doing another cold rolling, some Goss texture is newly formed from the shear band, and some Goss texture is retained in microbands. To determine whether additional heat treatment with H2 atmosphere is needed on decarburization process for growth of Goss texture, comparing between decarburization and heat treatment with H2 atmosphere is performed. Also, to find optimum condition for heat treatment, heat treatment with various time and temperature is performed. It was found that increase in the number of cold rolling and heat treatment increases Goss texture. Both high Goss texture and good columnar structure is achieved at 900℃, and this temperature is within a+r phase region. Heat treatment at a temperature higher than a+r phase region caused carbon diffusion and this made layer with Goss grain decrease.

Keywords: electrical steel, Goss texture, columnar structure, normal grain growth

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Authors: Laura Ulitzky, Dougbeh-Chris Nyan, Manuel M. Lafer, Erica Silberstein, Nicoleta Cehan, Deborah R. Taylor

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Hepatitis C virus (HCV)-associated hepatocellular carcinoma, fibrosis and cirrhosis are more frequent in men and postmenopausal women than in premenopausal women and women receiving hormone replacement therapy, suggesting that β-estradiol (estrogen) plays an innate role in preventing viral infection and liver disease. Estrogen classically acts through nuclear estrogen receptors or, alternatively, through the membrane-bound G-protein-coupled estrogen receptor (GPR30 or GPER). We observed a marked decrease in detectable virus when HCV-infected human hepatoma cells were treated with estrogen. The effect was mimicked by both Tamoxifen (Tam) and G1, a GPR30-specific agonist, and was reversed by the GPR30-specific antagonist, G15. Through GPR30, estrogen-mediated the down-regulation of occludin; a tight junction protein and HCV receptor, by promoting activation of matrix metalloproteinases (MMPs). Activated MMP-9 was secreted in response to estrogen, cleaving occludin in the extracellular Domain D, the motif required for HCV entry and spread. This pathway gives new insight into a novel innate immune pathway and the disparate host-virus responses to HCV demonstrated by the two sexes. Moreover, these data suggest that hormone replacement therapy may have beneficial antiviral properties for HCV-infected postmenopausal women and show promise for new antiviral treatments for both men and women.

Keywords: HCV, estrogen, occludin, MMPs

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Authors: Chui-Hsin Chen, Yu-Ting Chen

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Special concentrically braced frames is one of the seismic load resisting systems, which dissipates seismic energy when bracing members within the frames undergo yielding and buckling while sustaining their axial tension and compression load capacities. Most of the inelastic deformation of a buckling bracing member concentrates in the mid-length region. While experiencing cyclic loading, the region dissipates most of the seismic energy being input into the frame. Such a concentration makes the braces vulnerable to failure modes associated with low-cycle fatigue. In this research, a strategy to improve the cyclic behavior of the conventional steel bracing member is proposed by filling the Hollow Structural Shape (HSS) member with reinforcement. It prevents the local section from concentrating large plastic deformation caused by cyclic loading. The infill helps spread over the plastic hinge region into a wider area hence postpone the initiation of local buckling or even the rupture of the braces. The finite element method is introduced to simulate the complicated bracing member behavior and member-versus-infill interaction under cyclic loading. Fifteen 3-D-element-based models are built by ABAQUS software. The verification of the FEM model is done with unreinforced (UR) HSS bracing members’ cyclic test data and aluminum honeycomb plates’ bending test data. Numerical models include UR and filled HSS bracing members with various compactness ratios based on the specification of AISC-2016 and AISC-1989. The primary variables to be investigated include the relative bending stiffness and the material of the filling reinforcement. The distributions of von Mises stress and equivalent plastic strain (PEEQ) are used as indices to tell the strengths and shortcomings of each model. The result indicates that the change of relative bending stiffness of the infill is much more influential than the change of material in use to increase the energy dissipation capacity. Strengthen the relative bending stiffness of the reinforcement results in additional energy dissipation capacity to the extent of 24% and 46% in model based on AISC-2016 (16-series) and AISC-1989 (89-series), respectively. HSS members with infill show growth in 𝜂Local Buckling, normalized energy cumulated until the happening of local buckling, comparing to UR bracing members. The 89-series infill-reinforced members have more energy dissipation capacity than unreinforced 16-series members by 117% to 166%. The flexural rigidity of infills should be less than 29% and 13% of the member section itself for 16-series and 89-series bracing members accordingly, thereby guaranteeing the spread over of the plastic hinge and the happening of it within the reinforced section. If the parameters are properly configured, the ductility, energy dissipation capacity, and fatigue-life of HSS SCBF bracing members can be improved prominently by the infill-reinforced method.

Keywords: special concentrically braced frames, HSS, cyclic loading, infill reinforcement, finite element analysis, PEEQ

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Authors: Edward Hwang

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The efficiency of public policies depends on customer's satisfaction, and the change directions of public policies hinge on customer's assessment; i.e., the performance of public policies in governments is decided by the citizen's administrative satisfaction! The governments in all levels must heave their efficiency and effectiveness of public services to meet the people's substantially multiple needs in order to make citizens trust the governmental operation styles. To pursue the societal equality and justice, governments should treat people equally and provide more services for the disadvantages. The recent Dapu protest event involves Miaoli county Magistrate Liu cheng-hung who arbitrarily demolished houses and destroyed farmlands, and it shifts his popularity into disaffection. Liu case tells us that the political events are lethal to politicians; it cut almost 20% satisfaction degree for Magistrate Liu and hurt KMT support levels nationally. In terms of administrative satisfaction levels, political factors do matter, especially for the derogated events.

Keywords: local politics, administrative satisfaction, Taiwan, customer satisfaction

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Authors: Brenda R. Berca, Jessica S. Vieira, Lucas G. Candido, Matheus C. Ferreira, Paulo S. A. Lopes Filho, Rafaella O. Baracho

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This study aims to estimate the economic value environmental services sustained by Flamboyant Lourival Louza Municipal Park in Goiânia, Goiás, Brazil. The Flamboyant Park is one of the most relevant urban parks, and it is located near a stadium, a shopping center, and two supercenters. In order to define the methods used for the valuation of Flamboyant Park, the first step was carrying out bibliographical research with the view to better understand which method is most feasible to valuate the Park. Thus, the following direct methods were selected: travel cost, hedonic pricing, and contingent valuation. In addition, an indirect method (replacement cost) was applied at Flamboyant Park. The second step was creating and applying two surveys. The first survey aimed at the visitors of the park, addressing socio-economic issues, the use of the Park, as well as its importance and the willingness the visitors, had to pay for its existence. The second survey was destined to the existing trade in the Park, in order to collect data regarding the profits obtained by them. In the end, the characterization of the profile of the visitors and the application of the methods of contingent valuation, travel cost, replacement cost and hedonic pricing were obtained, thus monetarily valuing the various ecosystem services sustained by the park. Some services were not valued due to difficulties encountered during the process.

Keywords: contingent valuation, ecosystem services, economic environmental valuation, hedonic pricing, travel cost

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Authors: L. Alejandro Cárdenas, Fernando Herrera, David Nova, Juan Ballesteros

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This paper presents a methodology to optimize the maintenance of grid-connected photovoltaic systems, considering the cleaning and module replacement periods based on an asset management strategy. The methodology is based on the analysis of the energy production of the PV plant, the energy feed-in tariff, and the cost of cleaning and replacement of the PV modules, with the overall revenue received being the optimization variable. The methodology is evaluated as a case study of a 5.6 kWp solar PV plant located on the Bogotá campus of the Universidad Nacional de Colombia. The asset management strategy implemented consists of assessing the PV modules through visual inspection, energy performance analysis, pollution, and degradation. Within the visual inspection of the plant, the general condition of the modules and the structure is assessed, identifying dust deposition, visible fractures, and water accumulation on the bottom. The energy performance analysis is performed with the energy production reported by the monitoring systems and compared with the values estimated in the simulation. The pollution analysis is performed using the soiling rate due to dust accumulation, which can be modelled by a black box with an exponential function dependent on historical pollution values. The pollution rate is calculated with data collected from the energy generated during two years in a photovoltaic plant on the campus of the National University of Colombia. Additionally, the alternative of assessing the temperature degradation of the PV modules is evaluated by estimating the cell temperature with parameters such as ambient temperature and wind speed. The medium-term energy decrease of the PV modules is assessed with the asset management strategy by calculating the health index to determine the replacement period of the modules due to degradation. This study proposes a tool for decision making related to the maintenance of photovoltaic systems. The above, projecting the increase in the installation of solar photovoltaic systems in power systems associated with the commitments made in the Paris Agreement for the reduction of CO2 emissions. In the Colombian context, it is estimated that by 2030, 12% of the installed power capacity will be solar PV.

Keywords: asset management, PV module, optimization, maintenance

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Authors: Ya-Ching Wang, Yi-Maun Subeq

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Background: There is a lack of evidence to understand differences in risk for developing breast cancer between sexual minority women and heterosexual women in Taiwan. The purpose of this study is to compare differences in risk for developing breast cancer between the two groups of Taiwanese women. Methods: An online cross-sectional survey was used to collect data. A total of 238 Taiwanese women (mean age 30.69 years old, SD=8.231, range 20-60) were recruited between December 2016 and February 2017, including 115 heterosexual women and 123 sexual minority women. Results: There were no significant differences between heterosexual women and sexual minority women in body mass index, history of non-malignant breast disease, age at menarche and menopause, use of hormone replacement therapy, use of hormone replacement therapy, nor the prevalence of breast cancer. The sexual minority women had higher rates of current drinking, smoking and using breast-bindings and also reported exercise more a week; the heterosexual women had higher rates of pregnancy, children, breastfeed, miscarriages, abortion and use of birth control pills. Discussion/Conclusion: There were significant differences between heterosexual women and sexual minority women in reproductive factors and behavioral risk factors for the development of breast cancer. In particular, the finding that the sexual minority women had higher rate of using breast-bindings (56.6%) than the heterosexual women (4.7%) should be further explore, in order to understand whether long-term breast compression is associated with the development of breast cancer.

Keywords: breast cancer, risk, sexual orientation, Taiwan

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Authors: Amirmozafar Benshams, Saman Shafeinejad, Mohammad Zaman Kabir, Farzad Hatami, Mohammadreza Khedmati, Mesbah Saybani

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Steel bars has been used in concrete structures for more than one hundred years but lack of corrosion resistance of steel reinforcement has resulted in many structural failures. Fiber Reinforced Polymer (FRP) bar is an acceptable solution to replace steel to mitigate corrosion problem. Since FRP is a brittle material its use in seismic region has been a concern. FRP RC structures can be made ductile by employing a ductile material such as Shape Memory Alloy (SMA) at the plastic hinge region and FRP at the other regions on the other hand SMA is highly resistant to corrosion. Shape Memory Alloy has the unique ability to undergo large inelastic deformation and regain its initial shape through stress removal therefore utilizing composite SMA-FRP bars not only have good corrosion resistance but also have good performance in seismic region. The result show indicate that such composite SMA-FRP bars can substantially reduce the residual drift with adequate energy dissipation capacity during earthquake.

Keywords: steel bar, shape memory alloy, FRP, corrosion

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Authors: Onada Olawale Ahmed

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As the intensification of aquaculture production increases on global scale, the growing concern of fish farmers around the world is related to cost of fish production, where cost of feeding takes substantial percentage. Fishmeal (FM) is one of the most expensive ingredients, and its high dependence in aqua-feed production translates to high cost of feeding of stocked fish. However, to reach a sustainable aquaculture, new alternative protein sources including cheaper plant or animal origin proteins are needed to be introduced for stable aqua-feed production. Spirulina is a cyanobacterium that has good nutrient profile that could be useful in aquaculture. This review therefore emphasizes on the nutritional value of Spirulina as a potential replacement of FM in aqua-feed. Spirulina is a planktonic photosynthetic filamentous cyanobacterium that forms massive populations in tropical and subtropical bodies of water with high levels of carbonate and bicarbonate. Spirulina grows naturally in nutrient rich alkaline lake with water salinity ( > 30 g/l) and high pH (8.5–11.0). Its artificial production requires luminosity (photo-period 12/12, 4 luxes), temperature (30 °C), inoculum, water stirring device, dissolved solids (10–60 g/litre), pH (8.5– 10.5), good water quality, and macro and micronutrient presence (C, N, P, K, S, Mg, Na, Cl, Ca and Fe, Zn, Cu, Ni, Co, Se). Spirulina has also been reported to grow on agro-industrial waste such as sugar mill waste effluent, poultry industry waste, fertilizer factory waste, and urban waste and organic matter. Chemical composition of Spirulina indicates that it has high nutritional value due to its content of 55-70% protein, 14-19% soluble carbohydrate, high amount of polyunsaturated fatty acids (PUFAs), 1.5–2.0 percent of 5–6 percent total lipid, all the essential minerals are available in spirulina which contributes about 7 percent (average range 2.76–3.00 percent of total weight) under laboratory conditions, β-carotene, B-group vitamin, vitamin E, iron, potassium and chlorophyll are also available in spirulina. Spirulina protein has a balanced composition of amino acids with concentration of methionine, tryptophan and other amino acids almost similar to those of casein, although, this depends upon the culture media used. Positive effects of spirulina on growth, feed utilization and stress and disease resistance of cultured fish have been reported in earlier studies. Spirulina was reported to replace up to 40% of fishmeal protein in tilapia (Oreochromis mossambicus) diet and even higher replacement of fishmeal was possible in common carp (Cyprinus carpio), partial replacement of fish meal with spirulina in diets for parrot fish (Oplegnathus fasciatus) and Tilapia (Orechromis niloticus) has also been conducted. Spirulina have considerable potential for development, especially as a small-scale crop for nutritional enhancement and health improvement of fish. It is important therefore that more research needs to be conducted on its production, inclusion level in aqua-feed and its possible potential use of aquaculture.

Keywords: aquaculture, spirulina, fish nutrition, fish feed

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Authors: Lemoussi Somia, Ouali Mohammed, Zemirline Adel

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In precision engineering, including precision positioning, micro-manipulation, robotic systems... a majority of these applications actuated by piezo stack used the compliant amplifier mechanism to amplifying motion and guiding it as needed utilize the flexibility of their components, in this paper, we present a novel approach introducing a symmetric structure comprising three stages, featuring rectangular flexure hinges with a compact size of 77mm×42mm×10mm. This design provides the capability for rotation, translation or a combination of both movements in both directions. The system allows for a displacement of 2107.5 μm when the input displacement of PZT is 50 μm while considering the material constraints of the aluminum alloy (7075 T6) which has a maximum admissible stress of 500 MPa However, our proposed design imposes additional constraints to ensure the stress remains below 361 MPa for optimal performance. These findings were obtained through finite element simulations conducted using ANSYS Workbench. Furthermore, our module facilitates precise control of various components within robotic systems, allowing for adjustable speeds based on specific requirements or desired outcomes.

Keywords: robotic, piezoelectric, compliant mechanism, flexure hinge

Procedia PDF Downloads 80

Authors: Rendani Mercy Makhwathana

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This paper intends to explore teachers' encounters when teaching English First Additional Language in rural public schools. Teachers are pillars of any education system around the globe. Educational transformations hinge on them as critical role players in the education system. Thus, teachers' encounters are worth consideration, for they impact learners' learning and the well-being of education in general. An exploratory qualitative approach was used in this paper. The population for this paper comprised all Foundation Phase teachers in the district. A purposive sample of 15 Foundation Phase teachers from five rural-based schools was used. Data were collected through classroom observation and individual face-to-face interviews. Data were categorized, analyzed, and interpreted. Amongst the revealed teachers' encounters are learners' inability to read and write and learners' lack of English language background and learners' lack of the vocabulary to express themselves. This paper recommends the provision of relevant resources and support to effectively teach English First Additional Language to enable learners' engagement and effective use of the English language.

Keywords: first additional language, english second language, medium of instruction, teacher professional development

Procedia PDF Downloads 79

Authors: O. A. Anjola, M. A. Adejobi, A. Ogunbameru, F. P. Agbaye, R. O. Odunukan

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This experiment was conducted for 8 weeks to evaluate the growth performance and economics of pullets fed on different dietary energy sources. A total of 300 Harco black was used for this experiment. The birds were completely randomized and divided into four diet treatment groups. Each treatment group had three replicates of twenty-five birds per replicate. Four diets containing maize, spaghetti, noodles, and biscuit was formulated to represent diet 1, 2, 3 and 4 respectively. Diet 1 containing maize is the control, while diet 2, 3, and 4 contains spaghetti, noodles, and biscuit waste meal at 100% replacement for maize on weight for weight basis. Performance indices on Feed intake, body weight, weight gain, feed conversion ratio (FCR) and economy of production were measured. Blood samples were also collected for heamatology and serum biochemistry assessment. The result of the experiment indicated that different dietary energy source fed to birds significantly (P < 0.05) affect feed intake, body weight, weight gain, and feed conversion ratio (FCR). The best cost of feed per kilogram of body weight gain was obtained in Spaghetti based diet (₦559.30). However, the best performance were obtained from diet 1(maize), it can be concluded that spaghetti as a replacement for maize in diet of pullet is most economical and profitable for production without any deleterious effects attached. Blood parameters of birds were not significantly (p > 0.05) influenced by the use of the dietary energy sources used in this experiment.

Keywords: growth performance, spaghetti, noodles, biscuit, profit, hematology, serum biochemistry

Procedia PDF Downloads 228

Authors: Abdul Murad Zainal Abidin, Tuan Suhaimi Salleh, Siti Nor Azila Khalid, Noryati Mustapa

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Quarry dust is a quarry end product from rock crushing processes, which is a concentrated material used as an alternative to fine aggregates for concreting purposes. In quarrying activities, the rocks are crushed into aggregates of varying sizes, from 75mm until less than 4.5 mm, the size of which is categorized as quarry dust. The quarry dust is usually considered as waste and not utilized as a recycled aggregate product. The dumping of the quarry dust at the quarry plant poses the risk of environmental pollution and health hazard. Therefore, the research is an attempt to identify the potential of quarry dust as an alternative building material that would reduce the materials and construction costs, as well as contribute effort in mitigating depletion of natural resources. The objectives are to conduct material characterization and evaluate the properties of fresh and hardened engineering brick with quarry dust mix proportion. The microstructures of quarry dust and the bricks were investigated using scanning electron microscopy (SEM), and the results suggest that the shape and surface texture of quarry dust is a combination of hard and angular formation. The chemical composition of the quarry dust was also evaluated using X-ray fluorescence (XRF) and compared against sand and concrete. The quarry dust was found to have a higher presence of alumina (Al₂O₃), indicating the possibility of an early strength effect for brick. They are utilizing quarry dust waste as replacement material has the potential of conserving non-renewable resources as well as providing a viable alternative to disposal of current quarry waste.

Keywords: building materials, cement replacement, quarry microstructure, quarry product, sustainable materials

Procedia PDF Downloads 182

Authors: B. X. Tchomeni, A. A. Alugongo, L. M. Masu

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This paper presents a 4-DOF nonlinear model of a cracked of Laval rotor established based on Energy Principles. The model has been used to simulate coupled torsional-lateral response of the cracked rotor stator-system with multiple parametric excitations, namely, rotor-stator-rub, a breathing transverse crack, unbalanced mass, and an axial force. Nonlinearity due to a “breathing” crack is incorporated by considering a simple hinge model which is suitable for small breathing crack. The vibration response of a cracked rotor passing through its critical speed with rotor-stator interaction is analyzed, and an attempt for crack detection and monitoring explored. Effects of unbalanced eccentricity with phase and acceleration are investigated. By solving the motion equations, steady-state vibration response is obtained in presence of several rotor faults. The presence of a crack is observable in the power spectrum despite the excitation by the axial force and rotor-stator rub impact. Presented results are consistent with existing literature and could be adopted into rotor condition monitoring strategies

Keywords: rotor, crack, rubbing, axial force, non linear

Procedia PDF Downloads 401

Authors: N. Z. van Hierden, Q. Yu, F. Gauvin

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Cement manufacturing is, because of its production process, among the highest contributors to CO₂ emissions worldwide. As cement is one of the major components in 3D printed concrete, achieving sustainability and carbon neutrality can be particularly challenging. To improve the sustainability of 3D printed materials, different CO₂-reducing strategies can be used, each one with a distinct level of impact and complexity. In this work, we focus on the development of these sustainable mixtures and finding alternatives. Promising alternatives for cement and clinker replacement include the use of recycled building materials, amongst which (calcined) bricks and roof tiles. To study the potential of recycled clay-based building materials, the application of calcinated clay itself is studied as well. Compared to cement, the calcination temperature of clay-based materials is significantly lower, resulting in reduced CO₂ output. Reusing these materials is therefore a promising solution for utilizing waste streams while simultaneously reducing the cement content in 3D concrete mixtures. In addition, waste streams can be locally sourced, thereby reducing the emitted CO₂ during transportation. In this research, various alternative binders are examined, such as calcined clay blends (LC3) from recycled tiles and bricks, or locally obtained clay resources. Using various experiments, a high potential for mix designs including these resources has been shown with respect to material strength, while sustaining decent printability and buildability. Therefore, the defined strategies are promising and can lead to a more sustainable, low-CO₂ mixture suitable for 3D printing while using accessible materials.

Keywords: cement replacement, 3DPC, circular building materials, calcined clay, CO₂ reduction

Procedia PDF Downloads 86

Authors: K. F. Khan, Samsuddin Khan

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The Paleoproterozoic phosphorite deposit of Sallopat block of Banswara district of Rajasthan belongs to kalinjara formation of lunavada group of Aravalli Super Group. The phosphorites are found to occur as massive, brecciated, laminated and stromatolitic associated with calcareous quartzite, interbedded dolomite and multi coloured chert. The phosphorites are showing alternate brown and grey coloured concentric rims which are composed of phosphate, calcite and quartz minerals. Petro-mineralogical studies of phosphorite samples using petrological microscope, XRD, FEG- SEM and EDX reveal that apatite-(CaF) and apatite-(CaOH) are phosphate minerals which are intermixed with minor amount of carbonate materials. Sporadic findings of the uniform tiny granules of partially anisotropic apatite-(CaF) along with dolomite, calcite, quartz, muscovite, zeolite and other gangue minerals have been observed with the replacement of phosphate material by quartz and carbonate. The presence of microbial filaments of organic matter and alternate concentric rims of stromatolitic structure may suggest that the deposition of the phosphate took place in shallow marine oxidizing environmental conditions leading to the formation of phosphorite layers as primary biogenic precipitates by bacterial or algal activities. Different forms and texture of phosphate minerals may be due to environmental vicissitudes at the time of deposition followed by some replacement processes and biogenic activities.

Keywords: apatite, petro-mineralogy, phosphorites, sallopat, stromatolites

Procedia PDF Downloads 353

Authors: Emrah Yaliniz, Ali Kalkanli

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ZE41A magnesium alloy has been extensively used in aerospace industry, especially for use in rotorcraft transmission casings. Due to the improved mechanical properties, the latest generation of magnesium casting alloy EV31A-T6 (Elektron 21® specified in AMS 4429) is seen as a potential replacement for ZE41A in terms of strength. Therefore, the necessity of enhancement has been arisen for ZE41A in order to avoid fully replacement. The main element affecting the strength of ZE41A is Zirconium (Zr), which acts as a grain refiner. The specified range of Zr element for ZE41A alloy is between 0.4 wt % and 1.0 wt % (unless otherwise stated by weight percentage after this point) as stated in AMS 4439. This paper investigates the effects of Zr amount on tensile and metallurgical properties of ZE41A magnesium alloy. The Zr alloying amount for the research has been chosen as 0.5 % and 1 %, which are standard amounts in a commercial alloy (average of 0.4-0.6%) and maximum percent in the standard, separately. 1 % Zr amount has been achieved via Zirmax (66.7 Mg-33.3 Zr) master alloy addition. The ultimate tensile strength of ZE41A with 1% Zr has been increased up to about 220-225 MPa in comparison to 200 MPa given in AMS 4439. The reason for the increase in strength with the addition of Zirmax is based on the decrease in grain size, which was measured about 30 µm. Optical microscope, scanning electron microscopy (SEM) and X-ray Diffraction (XRD) were used to detect the change in the microstructural futures via alloying. The zirconium rich coring at the center of the grains was observed in addition to the grain boundary intermetallic phases and bulk Mg-rich matrix. The solidification characteristics were also identified by using the cooling curve obtained from the sand casting mold during cooling of the alloys.

Keywords: aerospace, grain refinement, magnesium, sand casting, ZE41A

Procedia PDF Downloads 319

Authors: Yen-Luan Chen

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Maintenance has a great impact on the capacity of production and on the quality of the products, and therefore, it deserves continuous improvement. Maintenance procedure done before a failure is called preventive maintenance (PM). Sequential PM, which specifies that a system should be maintained at a sequence of intervals with unequal lengths, is one of the commonly used PM policies. This article proposes a generalized sequential PM policy for a system subject to shocks with imperfect maintenance and random working time. The shocks arrive according to a non-homogeneous Poisson process (NHPP) with varied intensity function in each maintenance interval. As a shock occurs, the system suffers two types of failures with number-dependent probabilities: type-I (minor) failure, which is rectified by a minimal repair, and type-II (catastrophic) failure, which is removed by a corrective maintenance (CM). The imperfect maintenance is carried out to improve the system failure characteristic due to the altered shock process. The sequential preventive maintenance-last (PML) policy is defined as that the system is maintained before any CM occurs at a planned time Ti or at the completion of a working time in the i-th maintenance interval, whichever occurs last. At the N-th maintenance, the system is replaced rather than maintained. This article first takes up the sequential PML policy with random working time and imperfect maintenance in reliability engineering. The optimal preventive maintenance schedule that minimizes the mean cost rate of a replacement cycle is derived analytically and determined in terms of its existence and uniqueness. The proposed models provide a general framework for analyzing the maintenance policies in reliability theory.

Keywords: optimization, preventive maintenance, random working time, minimal repair, replacement, reliability

Procedia PDF Downloads 277

Authors: K. Bala Subramanian, A. Siva, S. Swaminathan, Arul. M. G. Ajin

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Concrete is an essential building material which is widely used in construction industry all over the world due to its compressible strength. Curing of concrete plays a vital role in durability and other performance necessities. Improper curing can affect the concrete performance and durability easily. When areas like scarcity of water, structures is not accessible by humans external curing cannot be performed, so we opt for internal curing. Internal curing (or) self-curing plays a major role in developing the concrete pore structure and microstructure. The concept of internal curing is to enhance the hydration process to maintain the temperature uniformly. The evaporation of water in the concrete is reduced by self-curing agent (Super Absorbing Polymer – SAP) thereby increasing the water retention capacity of the concrete. The research work was carried out to reduce water, which is prime material used for concrete in the construction industry. Concrete curing plays a major role in developing hydration process. Concept of self-curing will reduce the evaporation of water from concrete. Self-curing will increase water retention capacity as compared to the conventional concrete. Proper self-curing (or) internal curing increases the strength, durability and performance of concrete. Super absorbing Polymer (SAP) used as internal curing agent. In this study 0.2% to 0.4% of SAP was varied in different grade of high strength concrete. In the experiment replacement of cement by silica fumes with 5%, 10% and 15% are studied. It is found that replacement of silica fumes by 10 % gives more strength and durability when compared to others

Keywords: compressive strength, high strength concrete rapid chloride permeability, super absorbing polymer

Procedia PDF Downloads 378