检索结果-南通市图书馆

A discrete-event model to simulate the effect of truck bunching due to payload variance on cycle time, hauled mine materials and fuel consumption

在线全文

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2016年第5期26卷 745-752页

作者： A.Soofastaei S.M.Aminossadati M.S.Kizil p.knights School of Mechanical and Mining Engineering The University of Queensland

Data collected from truck payload management systems at various surface mines shows that the payload variance is significant and must be considered in analysing the mine productivity,energy consumption,greenhouse gas emissions and associated cost.payload variance causes significant differences in gross vehicle weights.Heavily loaded trucks travel slower up ramps than lightly loaded trucks.Faster trucks are slowed by the presence of slower trucks,resulting in‘bunching’,production losses and increasing fuel consumptions.This paper simulates the truck bunching phenomena in large surface mines to improve truck and shovel systems’efficiency and minimise fuel consumption.The study concentrated on completing a practical simulation model based on a discrete event method which is most commonly used in this field of research in other industries.The simulation model has been validated by a dataset collected from a large surface mine in Arizona state,USA.The results have shown that there is a good agreement between the actual and estimated values of investigated parameters.

关键词： Discrete-event model Simulation Truck bunching payload variance Cycle time Fuel consumption

Gain-enabled optical delay readout unit using CMOS-compatible avalanche photodetectors

在线全文

学校读者我要写书评

暂无评论

photonics Research 2022年第10期10卷 2422-2433页

作者： RANJAN DAS YANRAN XIE HENRY FRANKIS KERU CHEN HERMANN RUFENACHT GUILLAUME LAMONTAGNE JONATHAN D.B.BRADLEY ANDREW p.knights Department of Engineering physics McMaster UniversityHamiltonOntario L8S 4L7Canada McDonald Detwiler Associates Sainte-Anne-de-BellevueQuebec H9X 3R2Canada

A compact time delay unit is fundamental to integrated photonic circuits with applications in,for example,optical beam-forming networks,photonic equalization,and finite and infinite impulse response optical filtering.In this paper,we report a novel gain-enabled delay readout system using a tunable optical carrier,low-frequency RF signal and CMOS-compatible photodetectors,suitable for silicon photonic integration.The characterization method relies on direct phase measurement of an input RF signal and thereafter extraction of the delay profile.Both integrated silicon and germanium photodetectors coupled with low-bandwidth electronics are used to characterize a microring resonator-based,true-time delay unit under distinct ring–bus coupling formats.The detectors,used in both linear and avalanche mode,are shown to be successful as optical-to-electrical converters and RF amplifiers without introducing significant phase distortion.For a Si–Ge separate-absorption-charge-multiplication avalanche detector,an RF amplification of 10 dB is observed relative to a Ge pIN linear detector.An all-silicon defect-mediated avalanche photodetector is shown to have a 3 dB RF amplification compared to the same pIN detector.All ring delay measurement results are validated by full-wave simulation.Additionally,the impact of photodetector biasing and system linearity is analyzed.

关键词： delay unit optical

A comparison of strategic mine planning approaches for in-pit crushing and conveying, and truck/shovel systems

在线全文

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2018年第2期28卷 205-214页

作者： M.Nehring p.F.knights M.S.Kizil E.Hay School of Mechanical and Mining Engineering The University of Queensland

In a global environment where energy and labor are becoming increasingly expensive, continuous mining systems such as In-pit Crushing and Conveying(IpCC) systems have been advanced as offering a real alternative to conventional truck haulage systems. The implementation of IpCC systems in hard rock operations in open pit mines however requires different and more comprehensive planning approaches in order to adequately reflect the practical aspects associated with these. This paper investigates the impact that these approaches may have on the implementation of IpCC systems on a basic metalliferous deposit amenable to open pit exploitation. A strategic life of mine plan to provide numerous economic indicators for each approach is analyzed and compared to traditional truck haulage systems. The mine planning and evaluation process highlights the increased overall resource recovery that may accompany the use of IpCC systems. This investigation also provides insights into the issues associated with IpCC and the scale and type of operation and orebody that is likely to provide a feasible alternative to truck haulage.

关键词： In pit crusher conveyor systems Strategic mine planning Resource recovery Surface metalliferous mining Mine optimization Truck and shovel

Integration of real options into short-term mine planning and production scheduling

在线全文

学校读者我要写书评

暂无评论

Mining Science and Technology 2009年第5期19卷 674-678页

作者： knights peter CRC Mining University of Queensland

Commodity prices have fallen sharply due to the global financial crisis. This has adversely affected the viability of some mining projects, including leading to the possibility of bankruptcy for some companies. These price falls reflect uncertainties and risks associated with mining projects. In recent years, much work has been published related to the application of real options pricing theory to value life-of-mine plans in response to long term financial uncertainty and risk. However, there are uncertainties and risks associated with medium/short-term mining operations. Real options theory can also be applied to tactical decisions involving uncertainties and risks. This paper will investigate the application of real options in the mining industry and present a methodology developed at University of Queensland, Australia, for integrating real options into medium/short-term mine planning and production scheduling. A case study will demonstrate the validity and usefulness of the methodology and techniques developed.

关键词：实物期权生产调度短期规划矿井不确定性采矿作业技术开发

A comprehensive investigation of loading variance influence on fuel consumption and gas emissions in mine haulage operation

在线全文

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2016年第6期26卷 995-1001页

作者： Soofastaei A. Aminossadati S.M. Kizil M.S. knights p. School of Mechanical and Mining Engineering University of Queensland

The data collected from haul truck payload management systems at various surface mines show that the payload variance is significant and must be considered in analysing the mine productivity, diesel energy consumption, greenhouse gas emissions and associated costs. The aim of this study is to determine the energy and cost saving opportunities for truck haulage operations associated with the payload variance in surface mines. The results indicate that there is a non-linear relationship between the payload variance and the fuel consumption, greenhouse gas emissions and associated costs. A correlation model, which is independent of haul road conditions, has been developed between the payload variance and the cost saving using the data from an Australian surface coal mine. The results of analysis for this particular mine show that a significant saving of fuel and greenhouse gas emissions costs is possible if the standard deviation of payload is reduced from the maximum to minimum value.

关键词：温室气体排放量矿山运输燃油消耗方差操作加载节约成本有效载荷

Geological uncertainty and risk:implications for the viability of mining projects

在线全文

学校读者我要写书评

暂无评论

Journal of Coal Science & Engineering(China) 2008年第2期14卷 176-180页

作者：李树兴 peter knights Doug Dunn CRC Mining The University of QueenslandBrisbane Q1d4069Australia BHp Billiton Mitsubishi Alliance(BMA) Australia

Computerized geological models are the basis of modern mine design,planning and production.A sound,validated geological model is essential to the success of a min- ing project.However,due to the complexity of geology surrounding deposits,geological models inherit uncertainty,or error.This geological uncertainty may significantly affect the risk profile of a mining project during its design and operational phases.Methodologies for quantifying geological uncertainty and risk have been developed by CRC Mining and the University of Queensland,Australia and successfully applied to case studies.This paper discussed the implications of geological uncertainty and risk to a coal mining project,and presents advances for quantifying geological/geotechnical uncertainty and risk.A case study is presented to demonstrate the application of the technology developed.

关键词：地质学不去定性风险采矿项目矿学

Guidance and Control System for platoon of Autonomous Mobile Robots

在线全文

学校读者我要写书评

暂无评论

Journal of Electrical Engineering 2018年第5期6卷 281-288页

作者： Vesna Antoska knights Zoran Gacovski Stojce Deskovski Olivera petrovska Faculty of Technology and Technical Sciences-Veles “St.Klement Ohridski”UniversityBitola 7000Republic of Macedonia Faculty of Informatics European UniversitySkopje 1000Republic of Macedonia Faculty of Technical Sciences “St.Klement Ohridski”UniversityBitola 7000Republic of Macedonia Faculty of Technical Sciences Mother Teresa UniversitySkopje 1000Republic of Macedonia

This paper presents a concept of platoon movement of autonomous vehicles(smart cars).Autonomous vehicles have ACC(adaptive or advanced cruise control)system also called ICC(intelligent cruise control)or AICC(adaptive intelligent cruise control)system.These vehicles are suitable to follow other vehicles on desired distance and to be organized in platoons.To be able to do research to the control and stability of an AGV(automated guided vehicles)string,a car-following model is being determined.To do this,first a single vehicle is modelled and since all cars in the platoon have the same dynamics,the single vehicle model is copied ten times to form model of platoon(string)with ten vehicles.To control this string,equal pID(proportional-integral-derivative)controllers are applied to all vehicles,except the leading vehicle.These controllers try to keep the headway distance as constant as possible and the velocity between subsequent vehicles error small.For control of vehicle with nonlinear dynamics combination of feedforward control and feedback control approach is used.Feedforward control is based on inverse model of nominal dynamics of the vehicle,and feedback pID control is designed on base of linearized model of the vehicle.For simulation and analysis of vehicle and platoon of vehicles Matlab/Simulink models are designed.Simulation results,discussions and conclusions are given at the end of the paper.

关键词： platoon of vehicles smart cars adaptive cruise control intelligent transportation system string stability

Effect of mammary stimulation on dairy cows and heifers exposed to a lactation induction protocol

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Animal Sciences 2014年第1期4卷 1-12页

作者： Reeza Ramgattie Narendra Siew Michael Diptee Valerie Stoute Marlon knights Division of Animal & Nutritional Sciences DCANRD West Virginia University Morgantown USA University of the West Indies School of Veterinary Medicine Trinidad West-Indies University of Trinidad & Tobago Trinidad West-Indies University of Trinidad & Tobago Trinidad West-Indies

Cows (n = 21), dried off for a minimum of 45 days, and nulliparous heifers (n = 26), at ages > 18 months old, were placed on a 12-day Lactation Induction (LI) protocol. One group of animals (including both cows and heifers) received 3-minute mammary gland stimulation, along with the LI protocol. Another group, again including both cows and heifers, received no stimulation only the LI protocol This consisted of two injections of prostaglandin F2α (pGF2α;25 mg) 11 days apart, followed by subcutaneous injections of 17β-estradiol (0.1 mg/kg BW/d) and progesterone (0.25 mg/kg BW/d) beginning 1 day later and continuing for seven (7) days. After this step, all animals received another injection of pGF2α on day 8, followed by intramuscular injections of reserpine (5 mg/d) and dexamethasone (20 mg/d) on each of days 9 to 12. All animals were milked, beginning on day 13, for a period of 154 days. For all animals, the success rate for lactation induction was 78% ± 6.3% and the mean weekly milk yield was 78.2 kg. Neither value was affected by mammary stimulation. parity did not significantly impact on the success rate but it did affect the mean weekly milk yield. Milk yield varied significantly (p peaking during week 9. peak milk production and persistency were 101.6 kg ± 5.9 kg and 16.9 weeks ± 2.4 weeks respectively, with neither being significantly (α = 0.05 level) affected by stimulation or by parity. However, heifers (at 8.2 weeks ± 1.0 week) tended (p = 0.1) to reach peak milk production earlier than cows (at 10.7 weeks ± 1.3). The milk produced was sold at a net profit per animal treated of $2206.31 TT. Hence, one can conclude that a Lactation Induction protocol can be a useful management tool to increase production and profitability of dairy operations in the tropics.

关键词： Mammary-Stimulation Lactation-Induction Cows Heifers

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

注塑充模不均的解决之道

现代塑料 2009年第9期 47-53页

作者： Mikell knights 《现代塑料》编辑部

随着多腔模具的使用日益频繁，以及模腔数量的不断增加，充模不均已成为注塑加工商在生产过程中必须面对和予以解决的问题。为此，热流道系统供应商及其他一些厂商均推出了各自解决方案。这些方案可能基于不同的技术，但它们的目的却是... 详细信息

随着多腔模具的使用日益频繁，以及模腔数量的不断增加，充模不均已成为注塑加工商在生产过程中必须面对和予以解决的问题。为此，热流道系统供应商及其他一些厂商均推出了各自解决方案。这些方案可能基于不同的技术，但它们的目的却是相同的，即实现注塑的均匀充模。

关键词：注塑加工充模热流道系统多腔模具生产过程供应商模腔