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A transition from a large open pit into a novel “macroblock variant” block caving geometry at Chuquicamata mine, Codelco Chile

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Journal of Rock Mechanics and Geotechnical Engineering 2019年第3期11卷 549-561页

作者： German Flores Alex Catalan Newcrest Mining Ltd. Melbourne3004Australia Codelco Chile Santiago8320000Chile

With a history of more than 100 years, Chuquicamata has become one of the largest open pits in the world. Its current depth of 1100 m, length of 4500 m and width of 3000 m, resulting in haulage distances of over 11,000 m from pit bottom to the processing plant or waste dumps, with waste/ore ratio greater than 4 and much lower grades, are effectively determining its profitable limit by the end of this decade. Currently, there are over 4300 Mt of geological resources containing 0.7% of copper and 340 ppm (1 ppm = 1 g/t) of molybdenum below the final pit shell. The corresponding orebody geometry is 3000 m northsouth, 300-800 m eastwest and the drilling campaign suggested the existence of more than 900 m of mineable ore from the final pit bottom. This is in spite of the fact that the Chuquicamata orebody is still open at depth. The business case to continue with the mining of the Chuquicamata orebody is to change from the current large open pit to a novel macroblock variant block caving geometry. This requires a production rate of 140,000 t/d (50 Mt per annum), with a continuous material handling system to achieve the 7-year ramp-up to full production. The resolution of a number of known technical, operational and logistical challenges outside current industry practises which Chuquicamata will face over its projected 40-year mine life is therefore essential. These challenges include simultaneous operations of open pit and underground macroblocks and from the initial lift to the second lift, rapid ramp-up and optimum sequencing of the planned macroblocks, early dilution from the west fault and late dilution from potential slope failures, and the potential for major operational hazards. An equally important issue to be addressed is cultural given that the mining history in the northern region of Chile, which includes Chuquicamata, is predominantly open pit. This paper presents a synopsis of the main challenges that the Chuquicamata underground project will face in order to meet the objectives of its corresponding busin

关键词： Macroblock variant Block caving Cave propagation Early and late dilutions Intensive preconditioning Rib pillar West fault Ore buffer

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buffer Management in the Sliding-Window (SW) Packet Switch for Priority Switching

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International Journal of Communications, Network and System Sciences 2014年第7期7卷 248-255页

作者： Alvaro Munoz Sanjeev Kumar Department of Electrical and Computer Engineering The University of Texas-Pan American Edinburg USA Samsung Inc. Richardson Texas USA

Switch and router architectures employing a shared buffer are known to provide high throughput, low delay, and high memory utilization. Superior performance of a shared-memory switch compared to switches employing other buffer strategies can be achieved by carefully implementing a buffer-management scheme. A buffer-sharing policy should allow all of the output interfaces to have fair and robust access to buffer resources. The sliding-window (SW) packet switch is a novel architecture that uses an array of parallel memory modules that are logically shared by all input and output lines to store and process data packets. The innovative aspects of the SW architecture are the approach to accomplishing parallel operation and the simplicity of the control functions. The implementation of a buffer-management scheme in a SW packet switch is dependent on how the buffer space is organized into output queues. This paper presents an efficient SW buffer-management scheme that regulates the sharing of the buffer space. We compare the proposed scheme with previous work under bursty traffic conditions. Also, we explain how the proposed buffer-management scheme can provide quality-of-service (QoS) to different traffic classes.

关键词： Sliding Windows Switch Priority Switching buffer Management

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buffer Standards for Physiological pH of the buffer N-(2-Acetamido)-2-aminoethanesulfonic Acid from 5°C to 55°C

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Open Journal of Physical Chemistry 2011年第3期1卷 118-123页

作者： Blake M. Bodendorfer Zachary M. Downs Isaac B. Henson Lakshmi N. Roy Rabindra N. Roy Jessica M. Stegner Jaime A. Veliz Joshua T. Wollen 不详

Electromotive force (emf) measurements of the Cell Pt(s), H2(g)|ACES(m1) + NaACES(m2) + NaCl (m3)| AgCl, Ag(s) have been carried out from 5°C to 55°C . The agreement of pH values between two calculated (extended Debye-Hückel and liquid junction correction) is very good. Two buffer solutions without the chloride ion and seven buffer solutions with NaCl, at an ionic strength (I = 0.16 mol.kg-1) similar to that of physiological fluids, have been studied. The pH values for these buffer solutions have been evaluated in the temperature range of 5°C to 55°C using the extended Debye-Hückel equation of the Bates-Guggenheim convention. Values of the residual liquid junction potential (δEj) between the ACES solutions and the saturated KCl calomel electrode solution have been estimated at 25°C and 37°C from the previously determined Ej values using the flowing junction cell to determine the operational pH values at 25°C and 37°C. These ACES buffer solutions are recommended as secondary standard reference solutions for pH measurements in the range of physiological applicati on at I = 0.16 mol.kg-1.

关键词： buffer Emf pH Zwitterionic

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Sectoral Advanced Planning Systems (APS) Based on Utility Functions

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Journal of Management Science & Engineering Research 2023年第2期6卷 32-46页

作者： Yuri Mauergauz Russian MES-Center Moscow119296Russian Federation

This paper contains the example of sectoral APS systems,for which the problem algorithmic space coincides with the relevant operational environment with great accuracy.The method of scheduling for technological processes with looping is described,based on the simultaneous application of two criteria:the value of relative direct costs and the average utility of order fulfillment.The influence of buffers on the work of shops is considered.The proposed method provides an automatic grouping of the same type of jobs on all machines involved while taking into account the required duration of jobs.A package of application programs has been developed that allows planning for an average number of orders.The result of the program is a set of non-dominant(not improved)options that are offered to the user for making a final decision.

关键词： Scheduling Production intensity buffer Job shop

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Effect of growth temperature of GaAsxSb1-x metamorphic buffer layer on electron mobility of InAs/AlSb heterostructures grown on Si substrate

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Chinese Physics B 2019年第11期28卷 364-369页

作者：张静吕红亮倪海桥杨施政崔晓然牛智川张义门张玉明 School of Microelectronics Xidian University and the State Key Discipline Laboratory of Wide Band Gap Semiconductor TechnologyXi’an 710071China State Key Laboratory for Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China

The InAs/AlSb heterostructures with step-graded GaAsxSb1-x metamorphic buffer layers grown on Si substrates by molecular beam epitaxy are studied. The step-graded GaAsxSb1-x metamorphic buffer layers are used to relax the strain and block defects at each interface of the layers. Meanwhile, adding Sb to GaAs is also beneficial to suppressing the formation of dislocations in the subsequent materials. The influences of the growth temperature of the step-graded GaAsxSb1-x metamorphic buffer layer on the electron mobility and surface topography are investigated for a series of samples. Based on the atomic force microscopy(AFM), high resolution x-ray diffraction(HRXRD), reciprocal space map(RSM), and Hall measurements, the crystal quality and composition of GaAsxSb1-x layer are seen to strongly depend on growth temperature while keeping the Ga growth rate and Ⅴ/Ⅲ ratio constant. The results show that the highest electron mobility is 10270 cm^2/V·s and the roughness is 4.3 nm for the step-graded GaAsxSb1-x metamorphic buffer layer grown at a temperature of 410℃.

关键词： Si sticking coefficients growth temperature GaAsxSb1-x metamorphic buffer

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Surface Modification of NiW Alloy Substrates

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稀有金属材料与工程 2011年第S3期40卷 380-382页

作者： Wang Xue1, 2, Li Chengshan2, Yu Zeming2, Zheng Huiling2, Ji Yongbin2, Chen Zewen 1, 2, Fan Zhanguo 1 1Northeastern University, Shenyang 110004, China 2Northwest Institute for Non-ferrous Metal Research, Xi’an 710016, China NW Inst Nonferrous Met Res Superconducting Mat Res Ctr Xian 710016 Peoples R China Northeastern Univ Shenyang 110004 Peoples R China

We have studied the adsorption of elemental S on the surfaces of NiW alloy substrates where elementary sulfur was used as sulfur source. Compared with those previous investigations which used H2S as the sulfur source and operated in an ultra-high vacuum chamber, we used elemental sulfur as the sulfur source which does not need an ultra-high vacuum chamber but Ar-H protection atmosphere in the process of sulfuration. After sulfuration, epitaxial LZO buffer layers were deposited on these substrates directly. The samples were investigated by means of AFM, XPS, SEM and XRD in this study. The results show that after sulfuration, S forms a c (2×2) structure at a coverage of 0.5 ML, in agreement with previous results, representing the effectiveness of elemental sulfur during the sulfuration process. The c (2×2)-S superstructure on the surface of the NiW substrates has optimized the La2Zr2O7(LZO) buffer layer texture.

关键词： NiW substrates sulfuration c (2×2) structure buffer layer

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Effect of Various Factors for the Electrochemical Adsorption of Polydopamine on TiO₂ Film

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Journal of Materials Science and Chemical Engineering 2022年第3期10卷 15-29页

作者： Naomu Takahashi Mikito Kitayama Department of Life Environment and Applied Chemistry Fukuoka Institute of Technology Fukuoka Japan

To fabricate polydopamine-sensitized solar cells with improved solar power conversion efficiency, the effects of pH, buffer, adsorption time and electrode potential for the electrochemical oxidation and polymerization of dopamine on TiO2 film were investigated. The optimum pH was around 7. It was found that the use of a buffer, especially 2-(N-morpholino)ethanesulfonic acid, significantly deteriorated the electrochemical adsorption of polydopamine, and the highest solar power conversion efficiency was obtained without buffer. With increasing adsorption time, the amount of adsorbed polydopamine increased but the solar power conversion efficiency decreased, suggesting the increased resistivity of polydopamine with a larger degree of polymerization. It was suggested that the reversal of electrode potential from positive to negative would be essential for the electrochemical adsorption of polydopamine.

关键词： Dye-Sensitized Solar Cell Dopamine Polydopamine Electrochemical Adsorption buffer

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buffer Standards for the Biochemical pH of the Zwitterionic buffer <i>N</i>-Tris-(Hydroxymethyl) Methyl-2-Aminoethanesulfonic Acid (TES) from 5℃ to 55℃

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Open Journal of Physical Chemistry 2012年第1期2卷 41-46页

作者： Rabindra N. Roy Lakshmi N. Roy Blake M. Bodendorfer Zachary M. Downs Stephen D. Rocchio Joshua T. Wollen Jessica M. Stegner Isaac B. Henson Nicholas W. Grove Lauren A. Dieterman Hoffman Department of Chemistry Drury University Springfield USA

The authors have undertaken the determination of pH values for one buffer solution of TES without NaCl and nine buffer solutions with NaCl yielding an ionic strength I = mol.kg-1. similar to that of blood. These buffer solutions have been evaluated in the temperature range of 5℃ to 55℃ using an extended version of the Debye-Hückel equation. The pH values are reported using 1) the Debye-Hückel extension of the Bates-Guggenheim convention in the tempera- ture range 5℃ to 55℃ and 2) with and without liquid junction correction at 25℃ and 37℃. These TES buffer solutions are recommended as secondary standard references for pH measurements in the range of pH 7.2 to 7.5 for physiological application with an ionic strength of I = 0.16 mol.kg-1.

关键词： Ionic Strength Liquid Junction Potentials Second Dissociation Constant buffer Solutions Activity Coefficients

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buffer standards for the physiological pH of the zwitterionic buffer 3-[<i>N</i>-tris(hydroxymethyl)methylamino]-2-hydroxypropanesulfonic Acid (TAPSO) From (278.15 to 328.15) K

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Journal of Biophysical Chemistry 2011年第4期2卷 414-421页

作者： Lakshmi N. Roy Rabindra N. Roy Blake M. Bodendorfer Zachary M. Downs Stephen D. Rocchio Jessica M. Stegner Isaac B. Henson 不详

The second dissociation constant, pK2, and related thermodynamic quantities for TAPSO have been previously determined and reported from the temperatures (278.15 to 328.15) K. In the current study there are five buffer solutions without NaCl and five buffer solutions with NaCl present which yield an ionic strength (I = 0.16 mol·kg-1) similar to that of blood plasma. These buffer solutions have been evaluated in the temperature range of (278.15 to 328.15) K using the extended Debye-Hückel equation, due to the limitations of the Bates-Guggenheim convention such that it is only valid when I -1. The liquid junction potential (Ej) values between the TAPSO solution and the saturated KCl calomel electrode solution have been estimated at (298.15 and 310.15) K using a flowing junction cell measurement. The previously mentioned Ej values have been used in determining the operational pH values at (298.15 and 310.15) K. These TAPSO buffer solutions are recommended as reference solutions for pH measurements in saline media with an ionic strength of I = 0.16 mol·kg-1.

关键词： Zwitterionic buffer pH Liquid Junction Physiological

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buffer Occupancy of Double-buffer Traffic Shaper in Real-Time Multimedia Applications across Slow-Speed Links

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Communications and Network 2013年第1期5卷 84-92页

作者： Ayodeji O. Oluwatope Damilola T. Oyewo Folake E. Olayiwola Ganiyu A. Aderounmu Emmanuel A. Adagunodo Comnetlab Network Utility Maximisation Sub-Group Computer Science and Engineering Obafemi Awolowo University Ile-Ife Nigeria

In this paper, a double-buffer traffic shaper was investigated to adjust video frame rate inflow into the TCP sender-buffer of a multimedia application source across a slow-speed link. In order to guarantee QoS across a slow-speed link (i.e. 1 MBPS), the double-buffer traffic shaper was developed. In this paper, the buffer size dynamics of double-buffer was investigated. The arrival and departure of frames were modeled as a stochastic process. The transition matrix for the process was generated and the stationary probability computed. A simulation program was written in Matlab 7.0 to monitor the buffer fullness of the second buffer when a 3600 seconds H.263 encoder trace data was used as test data. In the second buffer, it was discovered that over 90% of the play-time, the buffer occupancy was upper bounded at 300 frames per second and utilization maintained below 30%.

关键词： Multimedia Application Slow-Speed Link TCP buffer Occupancy QoS

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