Research on solar water heating system based on TRNSYS simulation optimization


Abstract: In this paper, the typical system of solar energy system: natural circulation system and forced circulation system are analyzed. The two systems are simulated on the TRNSYS platform, and the configuration of the system itself has been discussed. The purpose is to provide reference for the
scientific implementation of solar energy architecture integration. On the basis of summarizing the solar energy construction technology, the natural circulation system and the forced circulation system of solar hot water system have been discussed emphatically. The simulation experiment is designed
on the TRNSYS platform. The influence of different heat collection area and water tank volume on solar energy guarantee rate and system efficiency has been discussed by simulation data. Finally, the optimal allocation scheme of natural constraints of natural circulation and forced circulation has been

Keywords: TRNSYS platform; solar fraction; system efficiency; heat collector area; water tank volume

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Research on preparation of chrome tin purple red pigment by using eggshell


The solid-phase synthesis of Cr-Ca-Sn-Si purple red pigment, the preparation of chrome tin pink stains are studied by using eggshell, which is used as the raw materials introducing the calcium carbonate. Through the experiment of formula is optimized, and by controlling the calcinations temperature and
mineralizer measures a series of Cr-Ca-SnSi purple red pigments are prepared. The results showed that Cr-Ca-Sn-Si purple red pigments are prepared by using eggshell.

Keywords: Eggshell; Cr-Ca-Sn-Si purple red pigments; solid-phase method.

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Research on determining reasonable negative pressure based on the control of the goaf


Abstract: In order to study the law of spontaneous combustion in goaf under the condition of gas extraction, the method of beam tube monitoring and numerical analysis is adopted to obtain three dimensional distribution of oxygen concentration and contour map under the condition of different
negative pressure. Based on the way of regression analysis, reasonable negative pressure are determined. The results show that with the increase of negative pressure, the spontaneous combustion “three-zone” in goaf: the heat dissipation zone and the spontaneous combustion zone become wider and the suffocation zone narrows. At the same time, the trend of spontaneous
combustion zone presents to the deep part of the goaf; the amount of gas extraction increases first and then decreases with the increase of negative pressure. Combined with the trend of spontaneous combustion zone and the amount of gas extraction in goaf, and the reasonable negative pressure
value is 32kpa and verified.

Keywords: Gas-drainage; spontaneous combustion in goaf; regression analysis; negative pressure.

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Assessment of the impact of US Energy Policy on world oil prices


Abstract: The development of the energy sector in the United States of America (USA) represents a rivalry between two different approaches, which has intensified under the last three American administrations. The competition of approaches is expressed in the confrontation between supporters of energy based on renewable sources and supporters of traditional energy resources. A comparative analysis of changes in the energy sector, depending on the prevalence of a particular approach to
energy development, shows that external conditions play a key role in promoting the energy strategy. The strategy of priority development of “green” energy carried out under Barack Obama could not be realized because of the shale boom. As a result, many companies working with renewable energy sources did not stand up to the competition. The opposite approach of Donald Trump’s focus on developing traditional energy resources to ensure US energy security and to increase jobs has been hit by the COVID-19 pandemic, which has virtually nullified the US administration’s efforts under this
approach. The current concept of President J. Biden is aimed at continuing the strategy of Barack Obama for the development of “green” energy in the United States. Proponents of this concept hope for the possibility of its at least partial implementation in the absence of a shale boom. The lifting of
the embargo on the export of American oil has led to an increase in oil supplies abroad. As of 2018, the United States has overtaken Saudi Arabia in terms of oil and gas exports, taking a leading position in the global oil market. In 2019-2020, the United States retained the first place in the world in oil production. This article examines the conceptual approaches of American administrations to the issue of energy policy and analyzes the statistical data that characterize the traditional and “clean energy” industries. An important factor is the degree of influence of the US energy policy on global oil prices. To analyze this issue, this research uses curved regression equations to assess the impact of US energy policy on world oil prices under the administrations of Barack Obama and Donald Trump. The results of the correlation show that a more effective interaction between the variables was carried out during the presidency of Barack Obama, when Exports of Crude Oil influenced the price dynamics of oil
quotes with an inverse relationship. With the arrival of the Biden administration, the strategy started under Obama in favor of developing clean energy was continued. In the context of the spread of covid19, the growth of crisis phenomena in the national economy, the growth of production costs in the oil and gas industry, and the fall in the world energy prices, the development of green energy can have a certain effect, given the Biden administration’s approach to energy development. The subsequent
actions of the Biden administration may offset Trump’s efforts to develop traditional energy to strengthen the economic potential of the United States and strengthen the position of American companies in the global oil market.

Keywords: Renewable energy sources, traditional energy, oil and gas industry, CO2 emissions, export/import of energy resources, US Energy Policy

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A Comparative Study On The Rheological Properties Of Coal Water Slurries Using Sodium Tripoly-Phosphate And Carboxy-Methyl-Cellulose As Dispersants


Abstract: The effects of two anionic dispersants (polymeric-carboxy methyl cellulose: CMC and inorganic-sodium tripolyphosphate: STPP) on the rheological properties of coal water slurries (CWS) of varying solid loading were reported and compared. The rheological data was obtained in the shear
rate range of 60-160 s-1 and the data was fitted using power law model. For lower solid concentrations (10% and 20%), shear thickening behaviour was observed while shear thinning nature was seen for the higher solid loadings (30%,40% and 50%) for CWS with both the dispersants. For all slurries, an
increase in flow behaviour index values was seen with the increase of dispersant loading. For CWS of 10% and 20% solid loadings, lower values of flow behaviour index was observed with CMC as dispersant. On the other hand, lower values for flow behaviour index was seen with STPP as dispersant
for CWS of 30%, 40% and 50% solids loading. Although CMC was found very effective in reducing the apparent viscosity at lower dosages unlike STPP, the apparent viscosity values are quite sensitive to the loading of CMC as dispersant in comparison to STPP. This observed trend may be due to
aggressively induced negative charges upon the adsorption of CMC on coal particles at the tested dispersant dosages.

Keywords: Coal water slurry, high ash Indian coals, sodium tripoly-phosphate (STPP), carboxy-methylcellulose (CMC), rheology, flow behaviour index.

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An Approach To Assessment Of Post Mining-Induced Seismic Hazard In Kolar Gold Fields Mines – A Review


A common challenge faced in underground hardrock mines worldwide is post mining-induced seismicity, as the events have been quite disastrous, causing risk to the structures and lives. In the recent years, many of the worked out mining areas are slowly getting populated and in due course of time shall be posing environmental threat to the people residing above and to the surface structures like sudden void formations or sudden ground collapse becoming visible on the surface. Worked out or closed mines have most of the time shown existence of post mining-induced seismicity signatures. Some of the closed mines showing post mining induced seismicity in Korea, South Africa, Sweden and India are being discussed. Post mining induced seismicity observed in Kolar Gold Fields worked out mine still being felt since closure of deeper levels is discussed. As mining depth increases especially in hard rock mines, magnitude of stress increases, hence, the occurrence and severity of postmining induced seismicity also increases. The problem becomes more serious if proper fund allocation is not done to investigate these areas, may be due to the absence of economic interest once the mine site has been abandoned and in many cases, direct investigations inside the mines may not be possible due to stability problems or due to the ingress of water into the void spaces of the mining area. Several approaches and techniques adopted by researcher’s world over are being discussed in this paper, with a view to gaining insight into the techniques of evaluation of seismic hazard. Seismic vulnerability assessment should integrate the effects of all the seismic events occurring at different locations of mining area during mining and post mining, along with their uncertainties also being considered. Based on the recorded data and some of the derived parameters from previous years, an attempt
should be made to evaluate the existing risk prone areas. The past records of induced seismicity due to mining should be used as a precursor for identification of impending future events and their expected probable locations of occurrence. The methods discussed here for assessment of seismic hazard are based on direct waveform and seismic source parameters, parameters from indirect waveform methods, frequency-magnitude relationship based, and frequency content analysis based. From the assessment it is found that the choice of method that can be used depends on the period of monitoring (short-term monitoring, intermediate-term or long-term monitoring) and the objective of the study required to be achieved, this varies on site-to-site basis. The main focus is to show the importance and need to install a micro seismic monitoring system for long term assessment of seismic risk especially in abandoned/worked out mines showing post mining-induced seismicity.

Keywords: Induced seismicity, underground mines, abandoned mine, post mining-induced seismicity, regular monitoring, seismic hazard assessment

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Assessment Of Coal Pillar Stability Using Principal Component Analysis And Stepwise Selection And Elimination


Abstract: Prediction of pillar stability is one of the most critical tasks in underground mining industries. This pillar stability analysis requires many input parameters and some of them are difficult to be determined. Various statistical based analysis is presented in literature for assessing pillar stability
successfully. In the present work, the data from three mines had been to determine the factor of safety. A total of 63 pillar cases had been collected from the mines. Principal component analysis (PCA) and Stepwise selection and elimination (SSE) models were developed by using multi variate linear
regression (MLR) on 45 data sets and subsequently the proposed models were validated on 18 different data sets. The value of coefficient of determination (R2) is 0.86 and 0.84 for PCA and SSE respectively. The root mean square error for PCA and SSE are found to be 0.112 and 0.123 respectively. On validation of the proposed model developed by PCA and SSE, the PCA model provided a better validation results. Hence, PCA is recommended for modelling pillar stability.

Keywords: Pillar stability, factor of safety, PCA, SSE

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Stope boundary optimization for an underground copper deposit using mixed integer linear programming based algorithm


Abstract: Optimal ore body boundary and production area geometry (Stope) are essential to maximize the profit from an underground mining project subject to inherent physical, geotechnical and geological constraints. Number of researches have been introduced for stope boundary optimization
but true optimal solution in three dimensional spaces is still out of reach. This article proposed a computer programming based optimization model using mixed integer linear programming based algorithm that incorporate stope boundary optimization with varying cost of mining and selling price
of the metal. An actual ore body model was taken as case study to implement the algorithm in real mining scenario. In validation study, it is observed that, by using proposed model, the profit can be increased by 10% – 15% as compared to the present stoping practice. Simulating the optimal stope boundary by changing the various cost and price parameters helps to opt the best possible option for a given mining scenario to make most realistic plan.

Keywords: Stope, boundary, modelling, algorithm, ore body

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Sustainable growth of Indian coal industry: policy perspectives and recommendations.


Abstract: Coal is the most abundant fossil fuel resource in India, and the country’s industrial and economic heritage has been built upon indigenous coal. India is the world’s 3rd largest energy consumer after China and USA. However, as the country goes through profound economic and societal
transformations, such as economic and population growth, urbanization and industrialization, energy demand is expected to increase substantially. Looking into the significance of coal not only in the energy-mix but also in the economic development of India, the paper is aimed at an assessment of
coal sector in India which shall also help contextualize the place of coal in India’s contemporary energy, industrial and social sectors amidst a range of developments – both national and international – related to coal sector. The authors looked into various aspects of Indian coal sector from a policy
perspective and suggested subsequent course of action so the same can be used by Indian coal mining stakeholders towards the larger goal of sustainable growth of coal sector including coal mining. The analysis produced important policy recommendations for coal industry stakeholders including the
Indian Government, who is the sovereign owner of coal mine acreage in India.

Keywords: Coal; dry fuel; coal mining; coal regulations; sustainable growth; decarbonization; Industry 4.0

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Rheological Behaviour Of Water Based Mud Formulated With Sodium Hydroxide (Naoh) Plant Extracts


The rheological behaviour of drilling mud formulated with sodium hydroxide extracts of Bitter-leaf (BL), Pawpaw (PL), Almond (AL) and Moringa (ML) leaves applied as surfactant (emulsifiers) was studied. The rheological properties (plastic viscosity (PV), yield point (YP), and gel strength) of the mud
were measured using standard procedures. The mud specific gravity for BLEM and PLEM was observed to give same value (1.08) as that of the C1 mud. pH of the formulated mud were all alkaline and in the order BLEM (8.6) > PLEM (8.3) > ALEM (8.3) > C1(8.3) > MLEM (8.2) > C2 (8.2). The highest PV (19cP)
was recorded by PLEM at 30ºC, while the least value (6cP) was by C2 at 60ºC temperatures. Highest YP (70 1b/100ft2) was recorded by C2 while the lowest YP value (22 1b/100ft2) by C1 both at 30ºC. Gel strength at 10 seconds showed reduction in value as the temperature increased for MLEM, ALEM,
C2 and C1 formulated mud and recorded maximum of 45 1b/100 ft2 at 30ºC for C2 while the lowest gel strength was reported by C1 at 60ºC. The results obtained from the study showed that the various alkaline plant extracts used as emulsifying agent have no negative effect on the rheological properties
of the formulated mud, rather it enhances the rheological properties even after aging of the mud at 65oC. These results therefore, show the need to use the various plant extracts as alternative additive (emulsifying agent) in the formulation of water based drilling mud.

Keywords: NaOH-plant extracts, rheological properties, surfactant, drilling mud, emulsifying agent

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