scholarly journals Studi eksperimen kinerja turbin vortex berbasis gravitasi dengan sudu backward dan forward

2021 ◽  
Vol 11 (1) ◽  
pp. 74
Author(s):  
D.S. Pamuji ◽  
F. Akbar ◽  
A.N. Rohman ◽  
D. Sugati
Keyword(s):  
Large Scale ◽  
Negative Effects ◽  
Energy Potential ◽  
Rotating Speed ◽  
Flow Energy ◽  
Irrigation Channels ◽  
Natural Flow ◽  
Low Head ◽  
Brake Dynamometer ◽  
Optimal Efficiency

Nowadays, the use of hydro energy in Indonesia is still focused on large-scale hydropower development which has negative effects on the environment such as changes in the natural flow of rivers, disruption of the population of aquatic biota that live in these watersheds and has the risk of potential disasters if the dam fails. In fact, the energy potential from the mini-micro hydro source is 19,835 MW, but its utilization is still very low around 100 MW. Therefore, the extraction of water flow energy in the form of rivers and irrigation channels with very low head altitude differences is considered important and urgent so that a gravity vortex turbine-based mini / micro hydro research is proposed. Specifically, this study aims to analyze the performance of the vortex turbine with backward and forward blades in a conical basin through laboratory experimental devices. Experiments were carried out on a fluid flow rate of 120 liters per minute (lpm) and 100 lpm by loading using a prony brake dynamometer in order to obtain torque performance data on variations in turbine blade rotational speed. In this experiment, the results showed that the performance of the backward blade turbine was superior with its optimal efficiency reaching 36.7% at a discharge of 120 lpm and a rotating speed of 80 rpm than the forward blade which at a discharge of 120 lpm and a rotating speed of 80 rpm was only able to achieve its highest efficiency at 33.19%.

СОЦИАЛЬНО-ЭКОНОМИЧЕСКИЕ КОНФЛИКТЫ В РАМКАХ «КАПИТАЛИЗМА ПЛАТФОРМ»

2019 ◽  
Vol 14 (3) ◽  
pp. 33
Author(s):  
L. V. Tomin
Keyword(s):  
Large Scale ◽  
Network Effects ◽  
Corporate Control ◽  
Balance Of Power ◽  
Negative Effects ◽  
Potential Threat ◽  
Communication Infrastructure ◽  
Political Effects ◽  
Information And Communication ◽  
Integrated Information

The article is devoted to the analysis of the structure, the peculiarities of functioning and the socio-economic and political effects of the «platform capitalism». The basis of this model is the network effects produced by the integrated information and communication infrastructure, which contribute to the monopolization and the constant expansion of platform companies into new areas. The principle of functioning of this infrastructure is the continuous collection and further monetization of data extracted from the interactions of individuals among themselves or with one of the elements of a digitalized economy or government structures. Such an infrastructure — forms a potential threat of strengthening state and corporate control over citizens. In addition, the activities of platform companies produce negative effects on the labor market, reinforcing the process of precarization of employment. The integrated information and communication infrastructure of platform companies form a system of a kind of «digital Taylorism», which deprives the employee of autonomy and privacy in the workplace. The influence of digitalization, subjected to the technocratic logic of the neoliberal model of governance in democratic countries, strengthens the de-politicization of relations between the citizen and the state and further changes the balance of power between labor and capital in favor of the latter. Large-scale protests of the last years against the companies of “capitalism of platforms” demonstrated the structural contradictions of this model and formed new forms of organization and actions of grassroots workers of the “digital economy”.

Assessment of bioenergy development potential in agricultural enterprises

2020 ◽  
pp. 165-171
Author(s):  
Iryna Hryhoruk
Keyword(s):  
Renewable Energy ◽  
Large Scale ◽  
Agricultural Waste ◽  
General Structure ◽  
Geographical Location ◽  
Economic Assessment ◽  
Energy Resources ◽  
Industrial Complex ◽  
Renewable Energy Resources ◽  
Energy Potential

Exhaustion of traditional energy resources, their uneven geographical location, and catastrophic changes in the environment necessitate the transition to renewable energy resources. Moreover, Ukraine's economy is critically dependent on energy exports, and in some cases, the dependence is not only economic but also political, which in itself poses a threat to national security. One of the ways to solve this problem is the large-scale introduction and use of renewable energy resources, bioenergy in particular. The article summarizes and offers methods for assessing the energy potential of agriculture. In our country, a significant amount of biomass is produced every year, which remains unused. A significant part is disposed of due to incineration, which significantly harms the environment and does not allow earning additional funds. It is investigated that the bioenergy potential of agriculture depends on the geographical distribution and varies in each region of Ukraine. Studies have shown that as of 2019 the smallest share in the total amount of conventional fuel that can be obtained from agricultural waste and products suitable for energy production accounts for Zakarpattya region - 172.5 thousand tons. (0.5% of the total) and Chernivtsi region - 291.3 thousand tons. (0.9%). Poltava region has the greatest potential - 2652.2 thousand tons. (7.8%) and Vinnytsia - 2623.7 thousand tons. (7.7%). It should be noted that the use of the energy potential of biomass in Ukraine can be called unsatisfactory. The share of biomass in the provision of primary energy consumption is very small. For bioenergy to occupy its niche in the general structure of the agro-industrial complex, it is necessary to develop mechanisms for its stimulation. In addition, an effective strategy for the development of the bioenergy sector of agriculture is needed. The article considers the general energy potential of agriculture, its indicative structure. The analysis is also made in terms of areas. In addition, an economic assessment of the possible use of existing potential is identified.

Towards Control of an Estuary

1987 ◽  
Vol 19 (9) ◽  
pp. 155-174
Author(s):  
Henk L. F. Saeijs
Keyword(s):  
Shallow Water ◽  
Storm Surge ◽  
Salt Marshes ◽  
Large Scale ◽  
Western Europe ◽  
Oxygen Depletion ◽  
Negative Effects ◽  
Intertidal Flats ◽  
Environmental Consequences ◽  
Short Time

The Delta Project is in its final stage. In 1974 it was subjected to political reconsideration, but it is scheduled now for completion in 1987. The final touches are being put to the storm-surge barrier and two compartment dams that divide the Oosterschelde into three areas: one tidal, one with reduced tide, and one a freshwater lake. Compartmentalization will result in 13% of channels, 45% of intertidal flats and 59% of salt marshes being lost. There is a net gain of 7% of shallow-water areas. Human interventions with large scale impacts are not new in the Oosterschelde but the large scale and short time in which these interventions are taking place are, as is the creation of a controlled tidal system. This article focusses on the area with reduced tide and compares resent day and expected characteristics. In this reduced tidal part salt marshes will extend by 30–70%; intertidal flats will erode to a lower level and at their edges, and the area of shallow water will increase by 47%. Biomass production on the intertidal flats will decrease, with consequences for crustaceans, fishes and birds. The maximum number of waders counted on one day and the number of ‘bird-days' will decrease drastically, with negative effects for the wader populations of western Europe. The net area with a hard substratum in the reduced tidal part has more than doubled. Channels will become shallower. Detritus import will not change significantly. Stratification and oxygen depletion will be rare and local. The operation of the storm-surge barrier and the closure strategy chosen are very important for the ecosystem. Two optional closure strategies can be followed without any additional environmental consequences. It was essential to determine a clearly defined plan of action for the whole area, and to make land-use choices from the outset. How this was done is briefly described.

scholarly journals Vibration characteristics of triple-gear-rotor system in compressed air energy storage under variable torque load

2021 ◽  
Vol 104 (1) ◽  
pp. 003685042098705
Author(s):  
Xinran Wang ◽  
Yangli Zhu ◽  
Wen Li ◽  
Dongxu Hu ◽  
Xuehui Zhang ◽  
...  
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Element Model ◽  
Rotor System ◽  
Dynamic Responses ◽  
System Response ◽  
Rotating Speed ◽  
Torque Load ◽  
Set Up ◽  
Two Stages

This paper focuses on the effects of the off-design operation of CAES on the dynamic characteristics of the triple-gear-rotor system. A finite element model of the system is set up with unbalanced excitations, torque load excitations, and backlash which lead to variations of tooth contact status. An experiment is carried out to verify the accuracy of the mathematical model. The results show that when the system is subjected to large-scale torque load lifting at a high rotating speed, it has two stages of relatively strong periodicity when the torque load is light, and of chaotic when the torque load is heavy, with the transition between the two states being relatively quick and violent. The analysis of the three-dimensional acceleration spectrum and the meshing force shows that the variation in the meshing state and the fluctuation of the meshing force is the basic reasons for the variation in the system response with the torque load. In addition, the three rotors in the triple-gear-rotor system studied show a strong similarity in the meshing states and meshing force fluctuations, which result in the similarity in the dynamic responses of the three rotors.

scholarly journals Strategic deployment of riparian buffers and windbreaks in Europe can co-deliver biomass and environmental benefits

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Oskar Englund ◽  
Pål Börjesson ◽  
Blas Mola-Yudego ◽  
Göran Berndes ◽  
Ioannis Dimitriou ◽  
...  
Keyword(s):  
Agricultural Production ◽  
Large Scale ◽  
Production Systems ◽  
Riparian Buffers ◽  
Environmental Benefits ◽  
The European Union ◽  
Negative Effects ◽  
Nitrogen Emissions ◽  
Environmental Objectives ◽  
Eu Policies

AbstractWithin the scope of the new Common Agricultural Policy of the European Union, in coherence with other EU policies, new incentives are developed for farmers to deploy practices that are beneficial for climate, water, soil, air, and biodiversity. Such practices include establishment of multifunctional biomass production systems, designed to reduce environmental impacts while providing biomass for food, feed, bioenergy, and other biobased products. Here, we model three scenarios of large-scale deployment for two such systems, riparian buffers and windbreaks, across over 81,000 landscapes in Europe, and quantify the corresponding areas, biomass output, and environmental benefits. The results show that these systems can effectively reduce nitrogen emissions to water and soil loss by wind erosion, while simultaneously providing substantial environmental co-benefits, having limited negative effects on current agricultural production. This kind of beneficial land-use change using strategic perennialization is important for meeting environmental objectives while advancing towards a sustainable bioeconomy.

Risk Factors for a Positive Hepatitis C Status in Fishermen in Kuantan Malaysia

2019 ◽  
Vol 31 (3) ◽  
pp. 227-237
Author(s):  
Priya Lall ◽  
Rumana Saifi ◽  
Diva Baggio ◽  
Samantha Fitzsimmons Schoenberger ◽  
Martin Choo ◽  
...  
Keyword(s):  
Hepatitis C ◽  
Confidence Interval ◽  
Risk Taking ◽  
Odds Ratio ◽  
Large Scale ◽  
Adjusted Odds Ratio ◽  
Environmental Drivers ◽  
Negative Effects ◽  
Risk Taking Behaviors ◽  
Risk Communities

Malaysia currently has an estimated hepatitis C virus (HCV) prevalence of 1.3% with an infected population of 384,000. Fishermen in Malaysia are at risk of HCV infection due to injection drug use and disproportionately high rates of incarceration. This study used quantitative data from Project WAVES, a large-scale mixed methods project charting environmental drivers of risk-taking behaviors among a respondent-driven sample of 406 fishermen in Malaysia. Over a quarter of participants (27.9%) reported injecting drugs in the past month; 49.8% of the sample tested positive for HCV. Respondents who had previously been arrested displayed increased odds of being HCV-positive (adjusted odds ratio = 4.79, confidence Interval = 2.46-9.35). Participants who reported being in lock-up displayed close to 6-fold odds of being HCV-infected (adjusted odds ratio = 5.49, confidence interval = 2.77-10.90, P < .001). These findings underscore the need for policies and structural interventions targeting the negative effects of aggressive incarceration contributing to the burden of HCV among high-risk communities.

Flexibility Effects in a Single Link Robotic Manipulator

1993 ◽  
Author(s):  
C. Nataraj
Keyword(s):  
Large Scale ◽  
Robotic Manipulator ◽  
Flexible Beam ◽  
Rotating Speed ◽  
Weighted Residuals ◽  
Individual Interaction ◽  
Single Link ◽  
Rigid Mass ◽  
The Individual ◽  
Future Work

Abstract A single link robotic manipulator is modeled as a rotating flexible beam with a rigid mass at the tip and accurate energy expressions are derived. The resulting partial differential equations are solved using an approximate method of weighted residuals. From the solutions, coupling between axial and flexural deformations and the interactions with rigid body motions are rigorously analyzed. The emphasis in the current paper is not on an exhaustive analysis of existing systems but it is rather intended to compare and highlight the various flexibility effects in a relatively simple system. Hence, a nondimensional parametric analysis is performed to determine the effect of several parameters (including the rotating speed) on the errors and the individual interaction effects are discussed. Comparison with previous work in the field shows important phenomena often ignored or buried in large scale numerical analyses. Future work including application to multi-link robots is outlined.

Modelling the dynamics of a minimal protocell container

2005 ◽  
Vol 4 (1) ◽  
pp. 81-91 ◽  
Author(s):  
Martin Nilsson Jacobi ◽  
Steen Rasmussen ◽  
Kolbjørn Tunstrøm
Keyword(s):  
Self Assembly ◽  
Large Scale ◽  
Lattice Gas ◽  
Three Dimensional ◽  
Initial Distribution ◽  
Energy Potential ◽  
Time Dynamics ◽  
Amphiphilic Molecules ◽  
Head Groups ◽  
Simplifying Assumptions

This paper is a discussion on how reaction kinetics and three-dimensional (3D) lattice simulations can be used to elucidate the dynamical properties of micelles as a possible minimal protocell container. We start with a general discussion on the role of molecular self-assembly in prebiotic and contemporary biological systems. A simple reaction kinetic model of a micellation process of amphiphilic molecules in water is then presented and solved analytically. Amphiphilic molecules are polymers with hydrophobic (water-fearing), e.g. hydrocarbon tail groups, and hydrophilic (water-loving) head groups, e.g. fatty acids. By making a few simplifying assumptions an analytical expression for the size distribution of the resulting micelles can be derived. The main part of the paper presents and discusses a lattice gas technique for a more detailed 3D simulation of molecular self-assembly of amphiphilic polymers in aqueous environments. Water molecules, hydrocarbon tail groups and hydrophilic head groups are explicitly represented on a three-dimensional discrete lattice. Molecules move on the lattice proportional to their continuous momentum. Collision rules preserve momentum and kinetic energy. Potential energy from molecular interactions are also included explicitly. The non-trivial thermodynamics of large-scale and long-time dynamics are studied. In this paper we specifically demonstrate how, from a random initial distribution, micelles are formed and grow until they destabilize and can divide. Eventually a steady state of growing and dividing micelles is formed. Towards the end of the paper we discuss the relevance of the presented results to the design of a minimal artificial protocell.

scholarly journals Learning to be selfish? A large-scale longitudinal analysis of Dictator games played on Amazon Mechanical Turk

2019 ◽  
Author(s):  
Antonio Alonso Arechar ◽  
David Gertler Rand
Keyword(s):  
Longitudinal Analysis ◽  
Large Scale ◽  
Dictator Game ◽  
Mechanical Turk ◽  
Amazon Mechanical Turk ◽  
Social Setting ◽  
Negative Effects ◽  
Dictator Games

We investigate whether experience playing the Dictator Game (DG) affects prosociality by aggregating data from 37 experiments run on Amazon Mechanical Turk over a six-year period. While prior evidence has shown a correlation between experience on Amazon Mechanical Turk and selfishness, it is unclear to what extent this is the result of selection versus learning. Examining a total of 27,266 decisions made by 17,791 unique individuals, our data shows evidence of significant negative effects of both selection and learning. First, people who participated in a greater total number of our experiments were more selfish, even in their first game – indicating that people who are more likely to select into our experiments are more selfish. Second, a given individual tends to transfer less money over successive experiments – indicating that experience with the DG leads to greater selfishness. These results provide clear evidence of learning even in this non-strategic social setting.

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