scholarly journals Study on Magnetite Ore Crushing Assisted by Microwave Irradiation

Minerals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1127
Author(s):  
Jiawang Hao ◽  
Qingwen Li ◽  
Lan Qiao

High energy consumption in ore crushing brings great challenges to the mining industry. Microwave irradiation provides a promising solution for rock breaking. However, there is currently a lack of detailed understanding of the microwave parameters regarding magnetite ore. The purpose of this study is to fully understand the potential value of microwave irradiation applied in auxiliary crushing of magnetite ore. It is typically found that increasing power reduces the mechanical properties of ore, increasing energy utilization, and crushing degree, more than extending time. Based on wave impedance, this reveals the dependence of energy utilization on thermal damage. Increasing irradiation power, time and cooling rate will cause more transgranular cracks and cleavage tears in the crushed ore. Based on the separate microwave response of several minerals, the microwave-damage mechanism of magnetite ore is further demonstrated.

2014 ◽  
Vol 29 (2) ◽  
pp. 149-154 ◽  
Author(s):  
Shan HUANG ◽  
Ji-Gang WANG ◽  
Song LIU ◽  
Fan LI

2020 ◽  
Vol 9 (1) ◽  
pp. 386-398 ◽  
Author(s):  
Mahmood S. Jameel ◽  
Azlan Abdul Aziz ◽  
Mohammed Ali Dheyab

AbstractPlatinum nanoparticles (Pt NPs) have attracted interest in catalysis and biomedical applications due to their unique structural, optical, and catalytic properties. However, the conventional synthesis of Pt NPs using the chemical and physical methods is constrained by the use of harmful and costly chemicals, intricate preparation requirement, and high energy utilization. Hence, this review emphasizes on the green synthesis of Pt NPs using plant extracts as an alternative approach due to its simplicity, convenience, inexpensiveness, easy scalability, low energy requirement, environmental friendliness, and minimum usage of hazardous materials and maximized efficiency of the synthesis process. The underlying complex processes that cover the green synthesis (biosynthesis) of Pt NPs were reviewed. This review affirms the effects of different critical parameters (pH, reaction temperature, reaction time, and biomass dosage) on the size and shape of the synthesized Pt NPs. For instance, the average particle size of Pt NPs was reported to decrease with increasing pH, reaction temperature, and concentration of plant extract.


2015 ◽  
Vol 1092-1093 ◽  
pp. 1597-1600
Author(s):  
Zhong Hua Wang ◽  
Xin Ye Chen

The need to reduce carbon emission in Heilongjiang Province of China is urgent challenge facing sustainable development. This paper aims to make explicit the problem-solving of carbon emission to find low carbon emission ways. According to domestic and foreign literatures on estimating and calculating carbon emissions and by integrating calculation methods of carbon emissions, it was not possible to consider all of the many contributions to carbon emissions. Calculation model of carbon emissions suitable to this paper is selected. The carbon emissions of energy consumption in mining industry are estimated and calculated from 2005 to 2012, and the characteristics of carbon emission are analyzed at the provincial level. It makes the point that carbon emissions of energy consumption in mining industry can be reduced when we attempt to alter energy consumption structure, adjust industrial structure and improve energy utilization efficiency.


2015 ◽  
Vol 63 (3) ◽  
pp. 315-318 ◽  
Author(s):  
Carmen Beatriz Borges FORTES ◽  
Vicente Castelo Branco LEITUNE ◽  
Fabrício Mezzomo COLLARES ◽  
Nélio Bairros DORNELLES JUNIOR ◽  
Stéfani Becker RODRIGUES ◽  
...  

Objective: The objective of this study was to evaluate the effectiveness of disinfection methods in microwave and immersion in peracetic acid in heat-cured, self-cured and microwave-cured acrylic resin, contaminated with Candida albicans. Methods: Five specimens were prepared for each type of acrylic resin. All were infected with Candida Albicans, incubated at 37°C for 24 hours. The group which underwent microwave energy was irradiated with a power of 840W for 1 minute and the other group underwent disinfection by soaking of 0.2% peracetic acid for 5 minutes. Results: All samples proved to be contaminated after the incubation period. After the different processes of disinfection, both immersion in 0.2% peracetic acid as microwave irradiation were effective in disinfection of the 3 types of acrylic resins contaminated by Candida Albicans. Conclusion: Concluded that soaking in 0,2% peracetic acid for 5 minutes with microwave irradiation power 840W for 1 minute are effective methods for disinfecting heat-cured acrylic resin, self-cured acrylic resin and microwave-cured acrylic resin, contaminated with Candida Albicans.


Molekul ◽  
2016 ◽  
Vol 11 (2) ◽  
pp. 299 ◽  
Author(s):  
Adel Zamri ◽  
Hilwan Yuda Teruna ◽  
Ihsan Ikhtiarudin

Some 2’-hydroxychalcone analogues have been widely used as an intermediate to synthesize various heterocyclic compounds, such as flavanones, flavanonols, flavones, flavonols and others. The heterocyclic compounds are also known to have a variety of interesting bioactivities in the medicinal chemistry and also have potency to be applied  in material chemistry including in industry. Therefore, 2’-hydroxychalcone analogues are often synthesized by researchers as intermediate, both in research associated with drug discovery and material synthesis. The aim of this study is to investigate the effect of microwave irradiation power variations on the selectivity of reaction of 2’-hydroxychalcone analogue synthesis. The variations of power that have been used in this study were 100, 180, 300 and 450 W with using a domestic microwave. Based on the study, we conclude that the power variation of microwave irradiationwere proven to effect the selectivity of synthesis reaction. In this study, the most suitable irradiation power to be applied on this synthesis is 180 W.


1980 ◽  
Vol 239 (4) ◽  
pp. H469-H469
Author(s):  
Michael Goodlett ◽  
Kyran Dowling ◽  
Lynne J. Eddy ◽  
James M. Downey

The effect of either isoproterenol or propranolol on the metabolism of ischemic myocardium was examined. To ensure that all changes were due to changes in metabolism and not drug-induced changes in residual flow to the ischemic regions, we devised a preparation in which two coronary branches on the same heart were simultaneously perfused at a low flow rate. Microsphere measurements verified that the two ischemic regions were receiving identical blood flow rates. One branch received an infusion of 0.9% NaCl and the other received the drug. After 1 h both regions were biopsied and the high-energy phosphate levels in each region were determined. ATP and phosphocreatine each fell to about 50% of their starting values in the 0.9% NaCl-treated regions, and isoproterenol did not further depress the high-energy phosphate concentrations. Propranolol, on the other hand, significantly preserved the high-energy phosphate concentrations. We conclude that although isoproterenol seemed incapable of accelerating energy utilization in ischemic myocardium, propranolol is apparently capable of reducing it.


2019 ◽  
Vol 3 (3) ◽  
pp. 1018-1028
Author(s):  
Carl A Old ◽  
Ian J Lean ◽  
Heidi A Rossow

Abstract Net energy systems, such as the California Net Energy System (CNES), are useful for prediction of input:output relationships not because of fidelity to the laws of thermodynamics, but because they were designed to predict well. Unless model descriptions of input:output relationships are consistent with the laws of thermodynamics, conclusions regarding those relationships may be incorrect. Heat energy (HE) + recovered energy (RE) = ME intake (MEI) is basic to descriptions of energy utilization found in the CNES and is consistent with the laws of thermodynamics; it may be the only relationship described in the CNES consistent with the first law of thermodynamics. In the CNES, efficiencies of ME utilization for maintenance (km) and gain (kg) were estimated using ordinary least squares (OLS) equations. Efficiencies thus estimated using static linear models are often inconsistent with the biochemistry of processes underlying maintenance and gain. Reactions in support of oxidative mitochondrial metabolism are thermodynamically favorable and irreversible; these reactions yield ATP, or other high-energy phosphate bonds, used for what is generally termed maintenance. Synthesis of biomass (gain) is less thermodynamically favorable; reactions do not proceed unless coupled with hydrolysis of high-energy phosphate bonds and lie closer to equilibrium than those in support of oxidative mitochondrial metabolism. The opposite is described in the CNES (km > kg) due to failure of partitioning of HE; insufficient HE is accounted for in maintenance. Efficiencies of ME utilization (km and kg) as described in the CNES are variable. Further neither km nor kg are uniformly monotonic f (ME, Mcal/kg); for ME (Mcal/kg) <0.512 or >4.26, km are inconsistent with thermodynamically allowed values for efficiencies (>1.0); kg are a monotonically positive f (ME) concentration (Mcal/kg) for ME <3.27 Mcal/kg. For ME <1.42 Mcal/kg, kg are not in the range of thermodynamically allowed values for efficiencies (0 to 1.0). Variable efficiencies of ME utilization require that the first law may not be observed in all cases. The CNES is an excellent empirical tool for prediction of input:output relationship, but many CNES parameter estimates evaluated in this study lack consistency with biology and the laws of thermodynamics.


2020 ◽  
Vol 12 (8) ◽  
pp. 3122
Author(s):  
Zhao Yang ◽  
Hong Fang

Apart from promoting social-economic development and increasing social employment, the real estate industry in China has also brought up problems such as high energy consumption and high emissions. Scholars now focus more on energy conservation, emission reduction and sustainable development of real estate companies in their current research. The data used by this paper are three-year panel data from 2015 to 2018, with observations from 15 representative real estate companies. CO2 and green credit index are introduced as the undesirable output and the green output of real estate companies respectively. First, with the DEA model and the Malmquist index model, this paper evaluates the green productivity of real estate companies statically and dynamically. The Tobit model is then employed by the author to analyze factors that may affect green productivity. Our results indicate that (1) the green productivities of 15 Chinese real estate companies have improved by various degrees. The average green productivity rises from 0.701 in 2015 to 0.849 in 2018, indicating that the energy utilization rate of enterprises has gradually increased. From the calculation and decomposition of the Malmquist total factor productivity index, we know that technological progress is vital in improving the green productivity of real estate companies. (2) As for the influencing factors, the green productivity is positively related to factors such as policy compliance indicator P, environmental responsibility commitment indicator R, indicator of green innovation capability I, and indicator of green development information disclosure M. The asset-liability ratio on the contrary has a negative impact on green productivity. It’s worth to point out that the green innovation index and green productivity is significantly correlated and the correlation coefficient can be up to 0.636, which implies that the key to improving green productivity is to increase research and development investment.


Author(s):  
Milton Meckler

What does remain a growing concern for many users of Data Centers is their continuing availability following the explosive growth of internet services in recent years, The recent maximizing of Data Center IT virtualization investments has resulted in improving the consolidation of prior (under utilized) server and cabling resources resulting in higher overall facility utilization and IT capacity. It has also resulted in excessive levels of equipment heat release, e.g. high energy (i.e. blade type) servers and telecommunication equipment, that challenge central and distributed air conditioning systems delivering air via raised floor or overhead to rack mounted servers arranged in alternate facing cold and hot isles (in some cases reaching 30 kW/rack or 300 W/ft2) and returning via end of isle or separated room CRAC units, which are often found to fight each other, contributing to excessive energy use. Under those circumstances, hybrid, indirect liquid cooling facilities are often required to augment above referenced air conditioning systems in order to prevent overheating and degradation of mission critical IT equipment to maintain rack mounted subject rack mounted server equipment to continue to operate available within ASHRAE TC 9.9 prescribed task psychometric limits and IT manufacturers specifications, beyond which their operational reliability cannot be assured. Recent interest in new web-based software and secure cloud computing is expected to further accelerate the growth of Data Centers which according to a recent study, the estimated number of U.S. Data Centers in 2006 consumed approximately 61 billion kWh of electricity. Computer servers and supporting power infrastructure for the Internet are estimated to represent 1.5% of all electricity generated which along with aggregated IT and communications, including PC’s in current use have also been estimated to emit 2% of global carbon emissions. Therefore the projected eco-footprint of Data Centers into the future has now become a matter of growing concern. Accordingly our paper will focus on how best to improve the energy utilization of fossil fuels that are used to power Data Centers, the energy efficiency of related auxiliary cooling and power infrastructures, so as to reduce their eco-footprint and GHG emissions to sustainable levels as soon as possible. To this end, we plan to demonstrate significant comparative savings in annual energy use and reduction in associated annual GHG emissions by employing a on-site cogeneration system (in lieu of current reliance on remote electric power generation systems), introducing use of energy efficient outside air (OSA) desiccant assisted pre-conditioners to maintain either Class1, Class 2 and NEBS indoor air dew-points, as needed, when operated with modified existing (sensible only cooling and distributed air conditioning and chiller systems) thereby eliminating need for CRAC integral unit humidity controls while achieving a estimated 60 to 80% (virtualized) reduction in the number servers within a existing (hypothetical post-consolidation) 3.5 MW demand Data Center located in southeastern (and/or southern) U.S., coastal Puerto Rico, or Brazil characterized by three (3) representative microclimates ranging from moderate to high seasonal outside air (OSA) coincident design humidity and temperature.


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