Control strategies for ventilation networks in small‐scale mines using an experimental benchmark

2020 ◽  
Author(s):  
Oscar‐Oswaldo Rodriguez‐Diaz ◽  
David Fernando Novella‐Rodriguez ◽  
Emmanuel Witrant ◽  
Edinson Franco‐Mejia
Keyword(s):  
Control Strategies ◽  
Small Scale ◽  
Ventilation Networks

scholarly journals Review on Power Quality Enhancement and its effects on Micro Grid

IJOSTHE ◽  
2020 ◽  
Vol 7 (1) ◽  
pp. 5
Author(s):  
Ankeeta . ◽  
Vasant Acharya
Keyword(s):  
Power Quality ◽  
Distribution System ◽  
Power Plants ◽  
Control Strategies ◽  
Renewable Energy Sources ◽  
Electrical Power ◽  
Small Scale ◽  
Quality Enhancement ◽  
Reliability Of Operation ◽  
Unbalanced Loads

Power generation through the renewable energy sources has become more viable and economical than the fossil fuel based power plants. By integrating small scale distributed energy resources, microgrids are being introduced as an alternative approach in generating electrical power at distribution voltage level. The power electronic interface provides the necessary flexibility, security and reliability of operation between micro-sources and the distribution system. The presence of non-linear and the unbalanced loads in the distribution system causes power quality issues in the Microgrid system. This paper explores and reviews different control strategies developed in the literature for the power quality enhancement in microgrids.

Application of Digital Twin Concept for Supercritical CO2 Off-Design Performance and Operation Analyses

2020 ◽  
Author(s):  
Leonid Moroz ◽  
Maksym Burlaka ◽  
Tishun Zhang ◽  
Olga Altukhova
Keyword(s):  
Supercritical Co2 ◽  
Control Strategies ◽  
System Modeling ◽  
Performance Estimation ◽  
Cycle Performance ◽  
Small Scale ◽  
Part Load ◽  
Digital Twin ◽  
Design Performance ◽  
Cycle Simulation

Abstract To date variety of supercritical CO2 cycles were proposed by numerous authors. Multiple small-scale tests performed, and a lot of supercritical CO cycle aspects studied. Currently, 3-10 MW-scale test facilities are being built. However, there are still several pieces of SCO2 technology with the Technology Readiness Level (TRL) 3-5 and system modeling is one of them. The system modeling approach shall be sufficiently accurate and flexible, to be able to precisely predict the off-design and part-load operation of the cycle at both supercritical and condensing modes with diverse control strategies. System modeling itself implies the utilization of component models which are often idealized and may not provide a sufficient level of fidelity. Especially for prediction of off-design and part load supercritical CO2 cycle performance with near-critical compressor and transition to condensing modes with lower ambient temperatures, and other aspects of cycle operation under alternating grid demands and ambient conditions. In this study, the concept of a digital twin to predict off-design supercritical CO2 cycle performance is utilized. In particular, with the intent to have sufficient cycle simulation accuracy and flexibility the cycle simulation system with physics-based methods/modules were created for the bottoming 15.5 MW Power Generation Unit (PGU). The heat source for PGU is GE LM6000-PH DLE gas turbine. The PGU is a composite (merged) supercritical CO2 cycle with a high heat recovery rate, its design and the overall scheme are described in detail. The calculation methods utilized at cycle level and components’ level, including loss models with an indication of prediction accuracy, are described. The flowchart of the process of off-design performance estimation and data transfer between the modules as well. The comparison of the results obtained utilizing PGU digital twin with other simplified approaches is performed. The results of the developed digital twin utilization to optimize cycle control strategies and parameters to improve off-design cycle performance are discussed in detail.

3D printing of functional polymers for miniature machines

2022 ◽  
Author(s):  
Neng Xia ◽  
Dongdong Jin ◽  
Veronica Iacovacci ◽  
Li Zhang
Keyword(s):  
3D Printing ◽  
Control Strategies ◽  
Functional Materials ◽  
Functional Polymers ◽  
Small Scale ◽  
Self Healing ◽  
Power Sources ◽  
Miniature Robots ◽  
Composite Polymers ◽  
Printing Techniques

Abstract Miniature robots and actuators with micrometer or millimeter scale size can be driven by diverse power sources, e.g., chemical fuels, light, magnetic, and acoustic fields. These machines have the potential to access complex narrow spaces, execute medical tasks, perform environmental monitoring, and manipulate micro-objects. Recent advancements in 3D printing techniques have demonstrated great benefits in manufacturing small-scale structures such as customized design with programmable physical properties. Combining 3D printing methods, functional polymers, and active control strategies enables these miniature machines with diverse functionalities to broaden their potentials in medical applications. Herein, this review provides an overview of 3D printing techniques applicable for the fabrication of small-scale machines and printable functional materials, including shape-morphing materials, biomaterials, composite polymers, and self-healing polymers. Functions and applications of tiny robots and actuators fabricated by 3D printing and future perspectives toward small-scale intelligent machines are discussed.

scholarly journals A survey of plants used by rural small-scale farmers to control pests of cabbage in the Eastern Cape Province, South Africa

2018 ◽  
Vol 2 (1) ◽  
Author(s):  
Nolitha L. Skenjana ◽  
Maxwell A. Poswal
Keyword(s):  
South Africa ◽  
Pest Control ◽  
Control Strategies ◽  
Diamondback Moth ◽  
Botanical Insecticides ◽  
Small Scale ◽  
Eastern Cape Province ◽  
Eastern Cape ◽  
Plant Parts ◽  
Small Scale Farmers

Background: Resource-poor small-scale farmers often cannot afford the high prices of chemical insecticides to control pests on crops; as a result, some use botanical insecticides. Aim: The aim of the study was to document ethnobotanical pest control methods used by rural small-scale farmers to control pests of cabbage in the Eastern Cape Province of South Africa. Setting: 217 rural small-scale crop-producing farmers from 14 towns in the Amathole, Joe Gqabi, Alfred Nzo, Chris Hani and OR Tambo Districts participated in the study. Methods: Questionnaires were administered to consenting farmers between July and November in 2012, using the convenience and stratified purposive sampling techniques. Data collected were subjected to descriptive statistical analysis. Results: The majority of farmers using botanical insecticides were females above the age of 60 years. The farmers identified 23 plants, which they use in their pest control strategies against seven pests of cabbage. The annual herb Tagetes minuta L. (Asteraceae) was cited as the most commonly used herb by 47% of the respondents, followed by Chenopodium ambrosioides L. (Chenopodiceae), Aloe ferox Mills. (Asphodelaceae) and Nicotiana tabacum L. (Solanaceae). Various plant parts were used in combinations or alone in the preparation of formulations mainly against aphids, cutworms and the diamondback moth. Conclusion: The plants, plant parts, combinations and formulations used by farmers in their cabbage pest control strategies need to be scientifically authenticated for efficacy.

scholarly journals Integrating the Theory of Sampling into Underground Mine Grade Control Strategies: Case Studies from Gold Operations

Minerals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 238
Author(s):  
Dominy ◽  
Glass ◽  
O’Connor ◽  
Lam ◽  
Purevgerel
Keyword(s):  
Case Studies ◽  
Control Strategies ◽  
Control Process ◽  
Control Programme ◽  
Small Scale ◽  
Sampling Errors ◽  
Sample Collection ◽  
Representative Sampling ◽  
Grade Control ◽  
Theory Of Sampling

Grade control aims to deliver adequately defined tonnes of ore to the process plant. The foundation of any grade control programme is collecting high-quality samples within a geological context. The requirement for quality samples has long been recognised, in that these should be representative and fit-for-purpose. Correct application of the Theory of Sampling reduces sampling errors across the grade control process, in which errors can propagate from sample collection through sample preparation to assay results. This contribution presents three case studies which are based on coarse gold-dominated orebodies. These illustrate the challenges and potential solutions to achieve representative sampling and build on the content of a previous publication. Solutions ranging from bulk samples processed through a plant to whole-core sampling and assaying using bulk leaching, are discussed. These approaches account for the nature of the mineralisation, where extreme gold particle-clustering effects render the analysis of small-scale samples highly unrepresentative. Furthermore, the analysis of chip samples, which generally yield a positive bias due to over-sampling of quartz vein material, is discussed.

scholarly journals An appraisal of proportional integral control strategies for small scale waste heat to power conversion units based on Organic Rankine Cycles

Energy ◽  
2018 ◽  
Vol 163 ◽  
pp. 1062-1076 ◽  
Author(s):  
Matteo Marchionni ◽  
Giuseppe Bianchi ◽  
Apostolos Karvountzis-Kontakiotis ◽  
Apostolos Pesyridis ◽  
Savvas A. Tassou
Keyword(s):  
Waste Heat ◽  
Control Strategies ◽  
Power Conversion ◽  
Small Scale ◽  
Integral Control ◽  
Proportional Integral ◽  
Organic Rankine Cycles ◽  
Proportional Integral Control

Wave Energy Hyperbaric Converter: Small Scale Models, Prototype and Control Strategies

2012 ◽  
Author(s):  
Segen F. Estefen ◽  
Paula B. Garcia-Rosa ◽  
Eliab Ricarte ◽  
Paulo Roberto da Costa ◽  
Marcelo M. Pinheiro ◽  
...  
Keyword(s):  
Control Strategies ◽  
Applied Pressure ◽  
Ocean Waves ◽  
Wave Climate ◽  
Small Scale ◽  
Scale Models ◽  
Pressure Water ◽  
Climate Analysis ◽  
Brazilian Northeast ◽  
And Control

A device for electricity generation from ocean waves has been developed for installation on the Brazilian northeast coast. It is based on pumping modules and a two-stage accumulator linked to a hyperbaric chamber in order to provide a prescribed high pressure water flow, which operates a turbine coupled with an electrical generator. In the period between 2001 and 2007, wave tank testing of small-scale models have been carried out. A prototype with two pumping modules is presently installed in the Port of Pecém. This paper describes an overview of the device development since the first tests to the installation of the prototype. Wave climate analysis, design analysis and optimization studies have been developed and are briefly revised in this study. Furthermore, control strategies are proposed to optimize the electrical output considering the proper combination of both pressure and flow rate as a function of the predominant wave climate, when the applied pressure is constant and the generator is a synchronous machine.

Small Scale Wind Generation System: Part II – A Novel Quasi-Z-Source Inverter and FRG-QZSI-Micro Grid Interface

2017 ◽  
Vol 6 (1) ◽  
pp. 13
Author(s):  
M. Ramkumar ◽  
K. N. Srinivas
Keyword(s):  
Control Strategies ◽  
Research Work ◽  
Open Loop ◽  
Small Scale ◽  
Loop Control ◽  
Power Injection ◽  
System Part ◽  
Micro Grid ◽  
Wind Generation System ◽  
And Control

<p>This paper proposes modelling, analysis and control of a small scale wind energy conversion system employing a direct driven Flux Reversal Generator (FRG) connected to the micro grid through a quasi-Z-source inverter (QZSI). This entire research is made up of two major parts viz., FRG and QZSI. In the part I report of this research work, the role of FRG has been thoroughly modelled and verified. In this part II, the modelling and analysis of QZSI for this purpose is presented. In addition, the modified space vector PWM (SVPWM) technique is proposed in this paper to satisfy the shoot-through characteristic of QZSI, which is a novel. The interface of FRG and QZSI to inject power in to micro grid has been finally presented. The simulation results are validated with the analytical results. Section I discusses the open loop control of QZSI. The mathematical modelling of QZSI for this purpose is given and analytically validated. This flowed by section II in which the proposed SVPWM is presented. The procedure to obtain triggering pulses using this proposed modulation technique is discussed. Section III presents closed loop control strategies for QZSI. Section IV presents the micro grid<br />inte face and power injection.</p>

Water pollution problems posed by small industries: a case study of India and China

2002 ◽  
Vol 45 (8) ◽  
pp. 47-52 ◽  
Author(s):  
Anil Agarwal
Keyword(s):  
Pollution Control ◽  
Industrial Development ◽  
Control Strategies ◽  
Low Cost ◽  
Small Scale ◽  
Industrial Enterprises ◽  
Competitive Environments ◽  
Control Technologies ◽  
Small Industries ◽  
India And China

Small-scale industrial enterprises play a highly important role in the development of countries such as India and China since they tend to be labour-intensive, contribute to decentralised industrial development, and are flexible and responsive to emerging demands. However they also often use outdated and highly polluting technologies and, operating in very competitive environments, have very limited financial reserves to invest in “non-productive” pollution control technologies. There has been very little research anywhere into low-cost pollution-control technologies or more applicable pollution control strategies for this sector.

Autonomous Control Strategies for Very High Temperature Reactor Based Systems for Hydrogen Production

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
Pavel V. Tsvetkov ◽  
Ayodeji B. Alajo ◽  
David E. Ames
Keyword(s):  
High Temperature ◽  
Hydrogen Production ◽  
Control Strategies ◽  
Autonomous Control ◽  
Small Scale ◽  
Fuel Component ◽  
Analysis Methodology ◽  
Research Initiative ◽  
Core Self ◽  
Very High

This paper is focused on feasible autonomous control strategies for Generation IV very high temperature reactors (VHTRs)-based systems for hydrogen production. Various burnable poison distributions and fuel compositions are considered. In particular, utilization of transuranium nuclides (TRUs) in VHTRs is explored as the core self-stabilization approach. Both direct cycle and indirect cycle energy conversion approaches are discussed. It is assumed that small-scale VHTRs may be considered for international deployment as grid-appropriate variable-scale self-contained systems addressing emerging demands for hydrogen. A Monte Carlo-deterministic analysis methodology has been implemented for coupled design studies of VHTRs with TRUs using the ORNL SCALE 5.1 code system. The developed modeling approach provides an exact-geometry 3D representation of the VHTR core details properly capturing VHTR physics. The discussed studies are being performed within the scope of the U.S. DOE Nuclear Energy Research Initiative project on utilization of higher actinides (TRUs and partitioned minor actinides) as a fuel component for extended-life VHTR configurations.

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