scholarly journals Impact of the Automatic Control of a Coal Separation Process in a Jig on its Economic Efficiency

2016 ◽  
Vol 32 (3) ◽  
pp. 163-172
Author(s):  
Stanisław Cierpisz
Keyword(s):  
Control System ◽  
Ash Content ◽  
Density Fluctuations ◽  
Separation Process ◽  
Downward Movement ◽  
Discharge System ◽  
Density Fractions ◽  
Separation Density ◽  
The Impact ◽  
Imperfection Factor

Abstract The beneficiation process of fine coal in jigs consists of two phases: stratification of coal grains in the bed according to their density and then splitting the stratified material into the product and the discharged refuse. At first, during subsequent water pulsations induced by opening and closing of air valves, the stratification of coal grains takes place due to varied velocity of their upward and downward movement. Grains of low density migrate to upper layers and grains of high density migrate to lower layers of the bed. The material travels horizontally on a screen along the jig compartment with the flow of water. The stratification of grains due to their density is not perfect, because the velocity of their upward and downward movement depends in part on their diameter, shape and the way in which the material loosens within a given pulsation cycle. The distribution of coal density fractions in the bed, characterized by the imperfection factor I, has been investigated by many researchers. The imperfection factor I is defined as the ratio of the probable error Ep and the separation density ρ50 (I = Ep/ρ50). The distribution of coal density fractions for an ideal and a real stratification process was compared. The maximum mass of the product of the desired quality (ash content) can be achieved for the ideal process when the imperfection I = 0. The stratified bed is then, in the end part of the jig, split into the product which overflows the end wall of the compartment and the refuse (or middlings) discharged through the bottom gate. The separation density (cut point) is established by the tonnage of the discharged bottom product (opening of the discharge gate). The separation density depends also on the tonnage of raw coal feeding the jig, and its washability characteristics. The impact of variations in the separation density on product parameters has been analysed. The mass of the product is always greater when the separation density is constant over a given period of time – even if in spite of its variations the process renders the same average ash content. Hence, the conclusion is to stabilise the separation density at the desired value as accurately as possible. The analysis was performed for raw coal washed in a three-product jig at the separation densities of 1.5 and 1.8 g/cm3. Percent contents (in brackets) of density fractions in raw coal were: <1.35 g/cm3 (40%), 1.35–1.50 g/cm3 (12%), 1.50–1.65 g/cm3 (4%), 1.65–1.80 g/cm3 (4%), 1.80–1.95 g/cm3 (12%, >1.95 g/cm3 (30%) (average ash in raw coal was 35.5%). In the analysis, an increase in the imperfection by 0.02 resulted in the decrease of the product tonnage by ΔQc = 1.0%. In this case, separation densities were set to ensure the same ash content in products (for I = 0 the change in tonnage was accepted at ΔQc = 0). The simulation analysis presented in the paper focused on the impact that fluctuations in separation density have on the economic effects of a jig operation. The influence of the separation density fluctuations on the product tonnage turned out to be nonlinear; for ±0.04 g/cm3 (control system with the radiometric density meter) the decrease in the product tonnage was ca. 0.5 % and for ±0.12 g/cm3 it was ca. 5.0% (control system with a float). The above results indicate that the operation of a refuse discharge system in a jig plays an important role in the final results of coal separation process defined in terms of tonnage and quality of the product.

scholarly journals Cosmological model parameter dependence of the matter power spectrum covariance from the DEUS-PUR Cosmo simulations

2020 ◽  
Vol 500 (2) ◽  
pp. 2532-2542
Author(s):  
Linda Blot ◽  
Pier-Stefano Corasaniti ◽  
Yann Rasera ◽  
Shankar Agarwal
Keyword(s):  
Dark Energy ◽  
Power Spectrum ◽  
Cold Dark Matter ◽  
Matter Density ◽  
Density Fluctuations ◽  
Matrix Analysis ◽  
Model Parameter ◽  
Matter Power Spectrum ◽  
Non Gaussian ◽  
The Impact

ABSTRACT Future galaxy surveys will provide accurate measurements of the matter power spectrum across an unprecedented range of scales and redshifts. The analysis of these data will require one to accurately model the imprint of non-linearities of the matter density field. In particular, these induce a non-Gaussian contribution to the data covariance that needs to be properly taken into account to realize unbiased cosmological parameter inference analyses. Here, we study the cosmological dependence of the matter power spectrum covariance using a dedicated suite of N-body simulations, the Dark Energy Universe Simulation–Parallel Universe Runs (DEUS-PUR) Cosmo. These consist of 512 realizations for 10 different cosmologies where we vary the matter density Ωm, the amplitude of density fluctuations σ8, the reduced Hubble parameter h, and a constant dark energy equation of state w by approximately $10{{\ \rm per\ cent}}$. We use these data to evaluate the first and second derivatives of the power spectrum covariance with respect to a fiducial Λ-cold dark matter cosmology. We find that the variations can be as large as $150{{\ \rm per\ cent}}$ depending on the scale, redshift, and model parameter considered. By performing a Fisher matrix analysis we explore the impact of different choices in modelling the cosmological dependence of the covariance. Our results suggest that fixing the covariance to a fiducial cosmology can significantly affect the recovered parameter errors and that modelling the cosmological dependence of the variance while keeping the correlation coefficient fixed can alleviate the impact of this effect.

scholarly journals Assessment of Pellets from Three Forest Species: From Raw Material to End Use

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 447
Author(s):  
Miguel Alfonso Quiñones-Reveles ◽  
Víctor Manuel Ruiz-García ◽  
Sarai Ramos-Vargas ◽  
Benedicto Vargas-Larreta ◽  
Omar Masera-Cerutti ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Ash Content ◽  
Hot Water ◽  
Raw Material ◽  
Chemical Components ◽  
Energy Yield ◽  
Cellulose Content ◽  
Fixed Carbon ◽  
End Use ◽  
The Impact

This study aimed to evaluate and compare the relationship between chemical properties, energy efficiency, and emissions of wood and pellets from madroño Arbutus xalapensis Kunth, tázcate Juniperus deppeana Steud, and encino colorado Quercus sideroxyla Humb. & Bonpl. in two gasifiers (top-lit-up-draft (T-LUD) and electricity generation wood camp stove (EGWCS)) in order to determine the reduction of footprint carbon. In accordance with conventional methodologies, we determined the extracts and chemical components (lignin, cellulose, holocellulose), and the immediate analyses were carried out (volatile materials, fixed carbon, ash content and microanalysis of said ash), as well as the evaluation of emission factors (total suspended particulate matter (PM2.5), CO, CO2, CH4, black carbon (BC), elemental carbon (EC), and organic carbon (OC)). The results were statistically analyzed to compare each variable among species and gasifiers. The raw material analyzed showed how the pH ranged from 5.01 to 5.57, and the ash content ranged between 0.39 and 0.53%. The content values of Cu, Zn, Fe, Mg, and Ca ranged from 0.08 to 0.22, 0.18 to 0.19, 0.38 to 0.84, 1.75 to 1.90, and 3.62 to 3.74 mg kg−1, respectively. The extractive ranges from cyclohexane were 2.48–4.79%, acetone 2.42–4.08%, methanol 3.17–7.99%, and hot water 2.12–4.83%. The range of lignin was 18.08–28.60%. The cellulose content ranged from 43.30 to 53.90%, and holocellulose from 53.50 to 64.02%. The volatile material range was 81.2–87.42%, while fixed carbon was 11.30–17.48%; the higher heating value (HHV) of raw material and pellets presented the ranges 17.68–20.21 and 19.72–21.81 MJ kg−1, respectively. Thermal efficiency showed statistically significant differences (p < 0.05) between pellets and gasifiers, with an average of 31% Tier 3 in ISO (International Organization for Standardization) for the T-LUD and 14% (ISO Tier 1) for EGWCS, with Arbutus xalapensis being the species with the highest energy yield. The use of improved combustion devices, as well as that of selected raw material species, can reduce the impact of global warming by up to 33% on a cooking task compared to the three-stone burner.

Modeling Hypervelocity Impacts Using Smoothed Particle Hydrodynamics

2018 ◽  
Author(s):  
M. Ganser ◽  
B. van der Linden ◽  
C. G. Giannopapa
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Large Deformations ◽  
Hypervelocity Impact ◽  
Density Fluctuations ◽  
Computational Domain ◽  
Simulation Tool ◽  
Hypervelocity Impacts ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
The Impact

Hypervelocity impacts occur in outer space where debris and micrometeorites with a velocity of 2 km/s endanger spacecraft and satellites. A proper shield design, e.g. a laminated structure, is necessary to increase the protection capabilities. High velocities result in massive damages. The resulting large deformations can hardly be tackled with mesh based discretization methods. Smoothed Particle Hydrodynamics (SPH), a Lagrangian meshless scheme, can resolve large topological changes whereas it still follows the continuous formulation. Derived by variational principles, SPH is able to capture large density fluctuations associated with hypervelocity impacts correctly. Although the impact region is locally limited, a much bigger domain has to be discretized because of strong outgoing pressure waves. A truncation of the computational domain is preferable to save computational power, but this leads to artificial reflections which influence the real physics. In this paper, hypervelocity impact (HVI) is modelled by means of basic conservation assumptions leading to the Euler equations of fluid dynamics accompanied by the Mie-Grueneisen equation of state. The newly developed simulation tool SPHlab presented in this work utilizes the discretization method smoothed particle hydrodynamics (SPH) to capture large deformations. The model is validated through a number of test cases. Different approaches are presented for non-reflecting boundaries in order to tackle artificial reflections on a computational truncated domain. To simulate an HVI, the leading continuous equations are derived and the simulation tool SPHlab is developed. The method of characteristics allows to define proper boundary fluxes by removing the inwards travelling information. One- and two-dimensional model problems are examined which show excellent absorption behaviour. An hypervelocity impact into a laminated shield is simulated and analysed and a simple damage model is introduced to model a spallation failure mode.

scholarly journals Valorization of briquettes fuel using Pinus spp. sawdust from five regions of Mexico

BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 2249-2263
Author(s):  
María Alejandra Ramírez-Ramírez ◽  
Artemio Carrillo-Parra ◽  
Faustino Ruíz-Aquino ◽  
Luis Fernando Pintor-Ibarra ◽  
Nicolás González-Ortega ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Impact Resistance ◽  
Resistance Index ◽  
Calorific Value ◽  
Volatile Matter ◽  
Ash Content ◽  
Fixed Carbon ◽  
Volumetric Expansion ◽  
Pinus Spp ◽  
The Impact

This research characterized briquettes made with Pinus spp. sawdust without the use of additives. For this purpose, 19 samples of sawdust from different wood industries located in five states of the Mexican Republic were used. The densification process was carried out in a vertical hydraulic piston laboratory briquette machine. The briquettes were made with 40 g of sawdust, at 50 °C, 20 kPa and pressing for 5 min. The results obtained varied as follows: moisture content (4.1% to 7.2%), density (813.9 to 1,014.4 kg/m3), volumetric expansion (7.4% to 37.3%), compressive strength (4.9 to 40.8 N/mm), impact resistance index (46.7% to 200%), ash (0.1% to 1.1%), volatile matter (82.9% to 90.7%), fixed carbon (8.9% to 16.4%), and calorific value (20.5 to 22.8 MJ/kg). The density of the briquettes was within the “acceptable” classification (800 to 1,200 kg/m3). It was observed that, the higher the density, the lower the volumetric expansion, the higher the compressive strength, and the higher the impact resistance index. According to the ash content, the briquettes could achieve international quality. Due to high volatile matter values, rapid combustion of the briquettes with little generation of toxic smoke would be expected. Fixed carbon and calorific value results were acceptable.

scholarly journals Comparison and Evaluation of Domestic and Foreign Radiation Environmental Standards for Nuclear Power Plants

2021 ◽  
Vol 2083 (2) ◽  
pp. 022020
Author(s):  
Jiahuan Yu ◽  
Xiaofeng Zhang
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
The United States ◽  
Discharge System ◽  
Radioactive Effluent ◽  
Effluent Discharge ◽  
The Impact

Abstract With the development of the nuclear energy industry and the increasing demand for environmental protection, the impact of nuclear power plant radiation on the environment has gradually entered the public view. This article combs the nuclear power plant radiation environmental management systems of several countries, takes the domestic and foreign management of radioactive effluent discharge from nuclear power plants as a starting point, analyses and compares the laws and standards related to radioactive effluents from nuclear power plants in France, the United States, China, and South Korea. In this paper, the management improvement of radioactive effluent discharge system of Chinese nuclear power plants has been discussed.

scholarly journals Pemanfaatan Limbah Kulit Buah Naga (Hylocereus costaricensis) dalam Pembuatan Teh Herbal dengan Penambahan Jahe

2017 ◽  
Vol 2 (3) ◽  
pp. 233-243
Author(s):  
Raudhatul Aiyuni ◽  
Heru Prono Widayat ◽  
Syarifah Rohaya
Keyword(s):  
Moisture Content ◽  
Sensory Evaluation ◽  
Block Design ◽  
Ash Content ◽  
Herbal Tea ◽  
Fruit Peel ◽  
Randomized Block Design ◽  
Dragon Fruit ◽  
Two Factors ◽  
The Impact

Abstrak. Tujuan penelitian untuk mengetahui pengaruh suhu pengeringan kulit buah naga dan konsentrasi penambahan jahe terhadap teh herbal serta mengetahui tingkat penerimaan konsumen terhadap teh herbal kulit buah naga dan jahe. Penelitian menggunakan Rancangan Acak Kelompok (RAK) Faktorial dengan 2 faktor. Faktor pertama adalah suhu pengeringan (T) yaitu T1 = 50⁰C, T2 = 60⁰C, T3 = 70⁰C. Faktor kedua adalah konsentrasi jahe (J) yaitu J1= 0%, J2= 10%, J3= 14%. Hasil penelitian menunjukkan bahwa suhu pengeringan berpengaruh sangat nyata (P≤0,01) terhadap kadar air, kadar abu, dan nilai organoleptik warna teh herbal kulit buah naga dan jahe yang dihasilkan, dan berpengaruh nyata (P≤0,05) terhadap nilai organoleptik rasa. Konsentrasi jahe (J) berpengaruh sangat nyata (P≤0,01) terhadap nilai organoleptik rasa teh herbal kulit buah naga dan jahe, dan berpengaruh nyata (P≤0,05) terhadap kadar air, dan nilai organoleptik warna. Interaksi suhu pengeringan dengan konsentrasi jahe (T×J) berpengaruh nyata (P≤0,05) terhadap nilai organoleptik rasa teh herbal kulit buah naga dan jahe. Berdasarkan hasil penelitian diperoleh perlakuan terbaik yaitu perlakuan dengan suhu pengeringan 50OC (T1) dan penambahan konsentrasi jahe 14% (J3) memiliki kadar air 10,89%, kadar abu 5,85%, aktivitas antioksidan 59,05% dan total fenol 6,07 mg GAE/g bahan. Utilization Of Waste Dragon Fruit Peel (Hylocereus Costaricensis) In The Production Of Herbal Tea With Additional Ginger Abstract. The purpose of this study was to know the impact of dried temperature and concentration additional of ginger and also to know the level of accept consumen for herbal tea dragon fruit peel and ginger. This study uses a randomized block design (RAK) Faktorial two factors. The first factor is dried temperature (T) that is T1 = 50⁰C, T2 = 60⁰C, T3 = 70⁰C. Factor II is consentration to add ginger (J) that is J1= 0%, J2= 10%, J3= 14%. The result of it showed that dried temperature obviously affected (P ≤ 0.01) on the moisture content, ash content, and sensory evaluation of color herbal tea dragon fruit peel and ginger, and obviously affected (P≤0,05) to the sensory evaluation of taste. While, the ginger consentration obviously affected (P ≤ 0.01) on the sensory evaluation of taste herbal tea dragon fruit peel and ginger, and obviously affected (P≤0,05) on the moisture content, and sensory evaluation of color. The interaction type of dried temperature with the ginger consentration obviously affected (P≤0,05) on the on the sensory evaluation of taste herbal tea dragon fruit peel and ginger. The best treatment is obtained from dried temperature 50°C (T1) and the addition of ginger concentration of 14% (J3) that product moisture content of  10,89%, ash content 5,85%,  antioxidant activity 59,05% and total phenol 6.07 mg GAE / g of material.

scholarly journals Management Control System (MCS) as a Package Elements Influence on Organizational Performance in the Pakistani context

2018 ◽  
Vol 6 (3) ◽  
pp. 280-295
Author(s):  
Shafique-ur Rehman ◽  
Rapiah Mohamed ◽  
Hazeline Ayoup
Keyword(s):  
Control System ◽  
Empirical Study ◽  
Organizational Performance ◽  
Textile Industry ◽  
Management Control ◽  
Current Paper ◽  
Management Control System ◽  
Resource Based View ◽  
The Impact ◽  
Levers Of Control

This paper intends to demonstrate the relationships between the management control system (MCS) as a package elements with organizational performance. Many studies conducted and investigated the impact of the management control system (levers of control) and organizational performance and ignore the elements of MCS as a package. Pakistan textile industry faces a lot of issues regarding MCS as packages elements and due to these issue organizational performance reduced. Therefore, current study portray a framework that consists of some vital elements of control adopted from Malmi and Brown (2008) MCS as a package like planning control, cybernetic controls, rewards and compensation controls, administrative controls, and cultural controls which if empirically investigated would demonstrate the extent of by in Pakistan textile industry and how these controls generate better organizational performance. This suggests that the need for more explanation of Pakistani textile industry managers on the need to adopt better MCS practices as these practices lead to better organizational performance. Although the current paper is conceptual in nature thus, needs an empirical study to address in the light of resource-based view theory.

Reducing the Impact of Source Information Uncertainty in Intelligent Automated Thermal Process Control Systems in Ensuring Reliable Operation of Power Equipment

Vestnik MEI ◽  
2021 ◽  
Vol 3 (3) ◽  
pp. 78-87
Author(s):  
Edik K. Arakelyan ◽  
◽  
Ivan A. Shcherbatov ◽  
Keyword(s):  
Control System ◽  
Process Control ◽  
Control Systems ◽  
Process Control System ◽  
Power Equipment ◽  
Source Information ◽  
Equipment Operation ◽  
Process Control Systems ◽  
Automated Process ◽  
The Impact

The uncertainty of the source information is used to solve key tasks in an intelligent automated thermal process control system affects the calculation of control actions, the implementation of equipment optimal operating modes and, as a result, leads to degraded reliability. As a rule, this type of information can be qualitative (the use of expert knowledge) or quantitative in nature. In this regard, it is extremely important to reduce the impact of uncertainty. The aim of the study is to identify the types and origins of uncertainty in the source information used by an intelligent automated process control system and to develop approaches to reduce its impact on the reliability of power equipment operation. The approaches used to ensure the specified indicators of reliability, efficiency and environmental friendliness in modern intelligent automated process control systems are based on predictive strategies, according to which the technical condition of equipment and specific degradation processes are predicted. This means that various types of uncertainty can have a significant negative impact. To reduce the influence of uncertainty of the initial information that affects the reliability of power equipment operation, the use of artificial neural networks is proposed. Their application opens the possibility to predict the occurrence of equipment defects and failures based on retrospective data for specified forecast time intervals. A method for reducing the impact of anomalies contained in the source information used in an intelligent process control system for energy facilities is demonstrated. Data omissions and outliers are investigated, the elimination of which reduces the impact of uncertainty and improves the quality of solving key problems in intelligent automated process control systems. Experimental studies were carried out that made it possible to identify the mathematical methods for removing omissions and anomalies in the source information in the best way. Methodological aspects of eliminating various types of uncertainty that exist in managing of power facilities by means of intelligent automated process control systems at the key stages of the power equipment life cycle are described.

scholarly journals Development of a model for the management of environmental safety of the region, taking into account of the GIS capacity

2018 ◽  
Vol 193 ◽  
pp. 02038 ◽  
Author(s):  
Viacheslav Burlov ◽  
Andrey Andreev ◽  
Fedor Gomazov
Keyword(s):  
Information System ◽  
Control System ◽  
Data Storage ◽  
Storage System ◽  
Practical Interest ◽  
Environmental Safety ◽  
Environmental Data ◽  
System Control ◽  
Results Management ◽  
The Impact

The system of space monitoring (SM) is of great importance, as a means of ensuring environmental safety. This system is based on remote sensing. The structure of SM is a distributed system. This system comprises independent data storage, system control, system of dynamic ratings, capacity and forecasting, control system, information system (IS) processing of monitoring data. As IS it is necessary to choose a geographic information system (GIS). IS monitoring refers to the problem-oriented system. These information systems include specialized databases models. All monitoring systems use sets of models, which allow building complex enterprise models. The peculiarity of the SM is the need to coordinate support of this monitoring and rate of the GIS capacity. Production Manager's decision is the impact on the object of monitoring. Results management and environmental data are received at the monitoring subsystem. Integration of SM and GIS monitoring has led to the creation of geoinformation space monitor (GISM). The operation of the system GISM is designed to provide a guaranteed result taking into account the capacity. Basis – the decision of the decision makers (DM). Therefore, an independent scientific and practical interest is the adequate mathematical model of DM.

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