scholarly journals Electric Power Generation from Low Head Simple Turbine for Remote Area Power Supply

2015 ◽  
Vol 74 (5) ◽  
Author(s):  
Erinofiardi Erinofiardi ◽  
Muhammad Syaiful ◽  
Adhy Prayitno

Over recent years, there has been an explosive growth of interest in the development of micro-hydropower generationturbine based on low head. Initial investment in building huge dams and large power stations is needed for high head turbine, beside these large dams are not environment friendly. Particularly in lower head, screw turbine is suitable for environment reason where this turbine has high efficiency, relatively lower cost and low environmental impact. Screw turbine can be applied in remote area which has water resource and no grid connection available. This paper reports experimental results examining the relationship between rotation speed and power. Laboratory scale of screw turbine is made by using locally available materials. Test results show that different speed of generator caused by different diameter of pulleys has great discrepency. 

1985 ◽  
Vol 107 (2) ◽  
pp. 197-203 ◽  
Author(s):  
Kenjiro Kamijo ◽  
Kunio Hirata

Several small cryogenic pumps for a liquid rocket engine have been made and tested. These pumps have a small impeller and are characterized by high speed and high head. The main design characteristics of these pumps are as follows: stage specific speeds of from 0.0319 to 0.0766, flow rates from 0.016 to 0.0525 m3/s, pressure rises from 4.9 to 26 MPa, rotational speeds from 16,500 to 80,000 rpm, and impeller diameters from 0.083 to 0.146 m. These pumps, when tested, showed higher efficiency even in the range of small stage specific speeds than any previously reported data on other pumps. This tendency was particularly striking with the two-stage pumps. With regard to pump efficiency measurement, it was made clear that adiabatic efficiency was utilizable for the present cryogenic pumps. The relationship between the adiabatic efficiency and ordinary efficiency was also confirmed by a brief calculation and test results.


Author(s):  
A. A. Gasiunas

An unparalleled increase in the output of power-generating units in the last decade has made it necessary to reconsider the established boiler feed pump design philosophy. This paper deals with a number of design aspects which are of vital importance for the future development of a modern high head per stage boiler feed pump. The paper discusses the pressure and depression pulses that are generated when impeller vanes travel past the stationary vanes of guide equipment. It is considered that these pressure fluctuations can cause cavitational damage in the impeller and other parts, and also the uneven running of a pump. The influence of geometrical and hydraulic non-symmetry on radial forces in a double volute casing is dealt with. Test results of a double suction model boiler feed pump are presented, including descriptions of durability runs with paint-coated hydraulic surfaces.


2020 ◽  
Vol 14 (1) ◽  
pp. 45-60
Author(s):  
Yashinta Yashinta ◽  
Dwi Hurriyati

This study aims to determine the relationship of loneliness with problematic internet use on boarding students on Silaberanti street in Siantan jaya Opposite Ulu 1 Palembang city. Research subjects numbered 220 people using random sampling methods. Data was collected using a 60 item problematic internet use scale and a 60 item loneliness. Realibility is generated on scale of problematic internet use of 0,955 and loneliness of 0,946.Hypothesis testing uses product moment correlation analysis techniques. Hypothesis test results showed a positive relationshif between loneliness with problematic internet use on boarding students on Silaberanti street in Siantan jaya Opposite Ulu 1 Palembang city r= 0,684 with a significance level of 0,000 (p<0,01). Loneliness in this study made an effective contribution of 46,8% to problematic internet use which can be seen from the coefficient of determination (r²) that is equel to 0,468.


2018 ◽  
Vol 69 (05) ◽  
pp. 381-389
Author(s):  
MENGÜÇ GAMZE SÜPÜREN ◽  
TEMEL EMRAH ◽  
BOZDOĞAN FARUK

This study was designed to explore the relationship between sunlight exposure and the mechanical properties of paragliding fabrics which have different colors, densities, yarn counts, and coating materials. This study exposed 5 different colors of paragliding fabrics (red, turquoise, dark blue, orange, and white) to intense sunlight for 150 hours during the summer from 9:00 a.m. to 3:00 p.m. for 5 days a week for 5 weeks. Before and after the UV radiation aging process, the air permeability, tensile strength, tear strength, and bursting strength tests were performed. Test results were also evaluated using statistical methods. According to the results, the fading of the turquoise fabric was found to be the highest among the studied fabrics. It was determined that there is a significant decrease in the mechanical properties of the fabrics after sunlight exposure. After aging, the fabrics become considerably weaker in the case of mechanical properties due to the degradation in both the dyestuff and macromolecular structure of the fiber


2019 ◽  
Vol 47 (10) ◽  
pp. 1-9 ◽  
Author(s):  
Xieping Chen ◽  
Qian Xie ◽  
Yuting Yang

Parent–adolescent communication is assumed to be an important factor affecting adolescent smoking behavior. However, the inner mechanism accounting for this association has still not been clarified in research. Our purpose in this study was to examine the relationships between parent–adolescent communication, adolescent smoking behavior, and depression, as well as gender differences in the relationship between depression and adolescent smoking behavior. Participants were 1,134 students at 6 junior high schools in China who completed the Parent-Adolescent Communication Scale, the Epidemiological Studies Depression Scale, and the Smoking Behavior Test. Results showed that parent-adolescent communication had a significant negative effect on adolescent smoking behavior and depression partially mediated the relationship between parent–adolescent communication and adolescent smoking behavior. In addition, gender moderated the relationship between depression and adolescent smoking behavior. Overall, these findings may help to promote better understanding of the relationship between parent–adolescent communication and adolescent smoking behavior.


2021 ◽  
pp. 1-18
Author(s):  
Ilina Cenevska

Abstract This case comment explores the relationship between two intertwined objectives – ensuring security of electricity supply and environmental protection – in the context of the judgment of the Court of Justice of the European Union in Inter-Environnement Wallonie ASBL and Bond Beter Leefmilieu Vlaanderen ASBL v. Conseil des ministres. The analysis focuses on the application of the Environmental Impact Assessment Directive and the Habitats Directive to the facts of the case, which concerns the extension by a ten-year period of the operation of two Belgian nuclear power stations (Doel 1 and Doel 2) as part of a national energy policy strategy to ensure the security of Belgium's electricity supply. The case comment also considers the legal and practical implications that arise as a result of employing the ‘security of electricity supply’ exemption to enable derogation from the requirements of the aforementioned Directives in circumstances where a Member State considers the security of its electricity supply to be under threat.


Author(s):  
Eunseong Jeong ◽  
Taesoo Lee ◽  
Alan Dixon Brown ◽  
Sara Choi ◽  
Minyoung Son

Governments have designated national parks to protect the natural environment against ecosystem destruction and improve individuals’ emotional and recreational life. National parks enhance environment-friendly awareness by conducting ecotourism activities and individuals with environment-friendly awareness are inclined to continue to visit national parks as ecotourism destinations. The New Environmental Paradigm (NEP) is a widely used measure of environmental concern, suitable for measuring the environment-friendly attitude and revisit intention of visitors of national parks. Therefore, the study carried out structural equation modeling (SEM) to investigate the relationship between the NEP, national park conservation consciousness and environment-friendly behavioral intention. Based on the results, an implication is presented to induce national parks to cultivate individual environment-friendly awareness and for visitors to pursue sustainable, environment-friendly tourism behavior. The findings indicate that national parks are to expand educational programs and facilities for eco-tourists visiting national parks to maintain a balanced relationship between themselves and nature and have a strong environmental awareness to preserve the natural environment.


Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1200
Author(s):  
Yong-Joon Jun ◽  
Seung-ho Ahn ◽  
Kyung-Soon Park

The Green Remodeling Project under South Korea’s Green New Deal policy is a government-led project intended to strengthen the performance sector directly correlated with energy performance among various elements of improvement applicable to building remodeling by replacing insulation materials, introducing new and renewable energy, introducing high-efficiency equipment, etc., with public buildings taking the lead in green remodeling in order to induce energy efficiency enhancement in private buildings. However, there is an ongoing policy that involves the application of a fragmentary value judgment criterion, i.e., whether to apply technical elements confined to the enhancement of the energy performance of target buildings and the prediction of improvement effects according thereto, thus resulting in the phenomenon of another important value criterion for green remodeling, i.e., the enhancement of the occupant (user) comfort performance of target buildings as one of its purposes, being neglected instead. In order to accurately grasp the current status of these problems and to promote ‘expansion of the value judgment criteria for green remodeling’ as an alternative, this study collected energy usage data of buildings actually used by public institutions and then conducted a total analysis. After that, the characteristics of energy usage were analyzed for each of the groups of buildings classified by year of completion, thereby carrying out an analysis of the correlation between the non-architectural elements affecting the actual energy usage and the actual energy usage data. The correlation between the improvement performance of each technical element and the actual improvement effect was also analyzed, thereby ascertaining the relationship between the direction of major policy strategies and the actual energy usage. As a result of the relationship analysis, it was confirmed that the actual energy usage is more affected by the operating conditions of the relevant building than the application of individual strategic elements such as the performance of the envelope insulation and the performance of the high-efficiency system. In addition, it was also confirmed that the usage of public buildings does not increase in proportion to their aging. The primary goal of reducing energy usage in target buildings can be achieved if public sector (government)-led green remodeling is pushed ahead with in accordance with biased value judgment criteria, just as in the case of a campaign to refrain from operating cooling facilities in aging public buildings. However, it was possible to grasp through the progress of this study that the remodeling may also result in the deterioration of environmental comfort and stability, such as the numerical value of the indoor thermal environment. The results of this study have the significance of providing basic data for pushing ahead with a green remodeling policy in which the value judgment criteria for aging existing public buildings are more expanded, and it is necessary to continue research in such a direction that the quantitative purpose of green remodeling, which is to reduce energy usage in aging public buildings, and its qualitative purpose, which is to enhance their environmental performance for occupants’ comfort, can be mutually balanced and secured at the same time.


Author(s):  
Toshimi Kobayashi ◽  
Toru Izaki ◽  
Junichi Kusumoto ◽  
Akihiro Kanaya

The small punch creep (SPC) test is possible to predict residual creep life at a high accuracy. But, the results of SPC tests cannot be compared with uniaxial creep or internal pressure creep results directly. In this report, the relationship between SPC test results and uniaxial creep test results in ASME A335 P11 (1.25Cr-0.5Mo Steel) was studied. The obtained relationship between SPC load and equivalent uniaxial creep stress formed a simple linear equation under the wide range of test temperature and test period. Then, the SPC results can be compared with uniaxial results by converting SPC loads to the equivalent uniaxial creep stresses. The relationship between SPC test results and internal pressure creep tests results was also studied. The internal creep life of as-received P11 pipe was almost same as SPC result when the hoop stress was converted to the SPC load. The creep lives of internal pressure creep influenced materials also showed good correspondence with SPC results. Therefore SPC can estimate the residual life of internal pressure creep influenced materials.


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