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Development of a multiple level underground limestone mine from geology through mine planning

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International Journal of Mining Science and Technology 2020年第1期30卷 63-67页

作者： christopher Newman David Newman Robert Dupuy Appalachian Mining&Engineering Inc.LexingtonKYUSA Rogers Group Inc.NashvilleTNUSA

The development of a multiple level underground mine is a complex task in which geology,engineering,ground control,and unit operations are integrated into a single mine *** components are interdependent and must function cohesively to ensure a profitable underground mining *** optimize reserve recovery,mine planning should begin from the lowest level and progress *** limits any misjudgments or oversights of a given level affecting the underlying levels and ensures the ability to maximize recovery from each *** planning should start with the exploration and characterization of the geologic *** the reserve geology and quality is well understood,then mine planning can begin with respect to the following:(1)orientation of mine works with respect to horizontal stress;(2)access to the reserve;(3)determination of opening widths;(4)selection of back,floor horizons and pillar centers;(5)selection of development and secondary mining heights;(6)appropriate inter-burden thicknesses;and(7)examining the stability of the multiple level mine through numerical *** multiple level mine design process and decisions are presented through a case history *** theme is that there is one opportunity to"get it right"and many chances to overlook a small aspect within the design that will plague the mine throughout all levels and through the entirety of its operating life.

关键词： Limestone Mine planning Geology Multiple level Rock mechanics

Thermally-actuated microfluidic membrane valve for point-of-care applications

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Microsystems & Nanoengineering 2021年第3期7卷 197-208页

作者： Muhsincan Sesen christopher J.Rowlands Department of Bioengineering Imperial College LondonLondonSW72AZUK

Microfluidics has enabled low volume biochemistry reactions to be carried out at the point-of-care.A key component in microfluidics is the microfluidic *** valves are not only useful for directing flow at intersections but also allow mixtures/dilutions to be tuned real-time and even provide peristaltic pumping *** the transition from chip-in-a-lab to lab-on-a-chip,it is essential to ensure that microfluidic valves are designed to require less peripheral equipment and that they are *** this paper,a thermally-actuated microfluidic valve is *** valve itself is fabricated with off-the-shelf components without the need for sophisticated cleanroom *** is shown that multiple valves can be controlled and operated via a power supply and an Arduino microcontroller;an important step towards transportable microfluidic devices capable of carrying out analytical assays at the *** is been calculated that a single actuator costs less than$1,this highlights the potential of the presented valve for scaling *** valve operation is demonstrated by adjusting the ratio of a water/dye mixture in a continuous flow microfluidic chip with Y-junction channel *** power required to operate one microfluidic valve has been characterised both theoretically and *** operation of the valve has been demonstrated for 65 h with 585 *** presented valve is capable of actuating rectangular microfluidic channels of 500μm×50μm with an expected temperature increase of up to 5°*** fastest actuation times achieved were 2 s for valve closing(heating)and 9 s for valve opening(cooling).

关键词： fluid valve Arduino

Orgasm-associated urinary in continence(climacturia)following radical prostatectomy:a review of pathophysiology and current treatment options

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Asian Journal of Andrology 2020年第6期22卷 549-554页

作者： christopher Kannady Jonathan Clavell-Hernandez Division of Urology McGovern Medical School at The University of Texas Health Science Center at HoustonHoustonTX 77030USA St.Joseph Medical Center HoustonTX 77002USA

Orgasm-associated urinary incontinence,or climacturia,is a common side effect after radical prostatectomy(RP)that is gaining more attention due to the distress it causes to patients.A range of treatment options have been reported in the literature and are outlined in this *** goal of our study is to review the pathophysiology and current management options for climacturia following RP.A PubMed search was used to review the current literature relating to the pathophysiology and the treatment of postprostatectomy *** reviewed the currently available treatment options and their success rates for *** techniques were found to subjectively help improve the amount and bother of patients'*** include pelvic floor muscle training(PFMT),penile variable tension loop,soft silicone occlusion loop,artificial urethral sphincter,male urethral sling,and the Mini-Jupette *** rates ranged from 48%to 100%depending on the modality *** patients with erectile dysfunction and climacturia,the Mini-Jupette graft could be a valuable *** the lack of validated measurement tools and management options,climacturia has become a challenge for *** a condition that has not garnered much attention,there are several management options from conservative to invasive treatments that have shown a hopeful promise for the treatment of *** options should be discussed with patients to determine the best treatment for each *** clinical trials are n eeded to assess the efficacy and impact of the d iff ere nt treatme nt options before a defi nitive recommendation regarding management can be made.

关键词： climacturia male urethral sling Mini-Jupette graft orgasm-associated urinary inc on tinence prostate can cer radical prostatectomy

Adventures and lessons of an American biochemist in China

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Protein & Cell 2011年第8期2卷 601-603页

作者： christopher J.Vavricka CAS Key Laboratory of Pathogenic Microbiology and Immunology Institute of MicrobiologyChinese Academy of SciencesBeijing 100101China

It’s very interesting how events often lead up to each other seemingly by chance,but appear almost perfectly planned out when looking *** the past two years,I have worked as an International Young Scientist Research Fellow at the Institute of Microbiology,Chinese Academy of Sciences in Beijing,*** people ask me,especially Chinese graduate students,why an American would choose to come to China as a postdoctoral researcher.

关键词： looking doctor perfectly

Exotic and excited-state meson spectroscopy and radiative transitions from lattice QCD

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Chinese Physics C 2010年第9期34卷 1512-1515页

作者： christopher E.Thomas Jefferson Laboratory

We discuss recent progress in extracting the excited meson spectrum and radiative transition form factors from lattice *** mention results in the charmonium sector,including the first lattice QCD calculation of radiative transition rates involving excited charmonium states,highlighting results for high spin and exotic *** present recent results on a highly excited isovector meson spectrum from dynamical anisotropic *** carefully constructed operators we show how the continuum spin of extracted states can be reliably identified and confidently extract excited states,states with exotic quantum numbers and states of high *** spectrum includes the first spin-four state extracted from lattice *** conclude with some comments on future prospects.

关键词： lattice QCD exotics mesons spectroscopy

Numerical prediction of the frictional losses in sliding bearings during start-stop operation

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Friction 2021年第3期9卷 583-597页

作者： Florian KÖNIG christopher SOUS Georg JACOBS Institute for Machine Elements and Systems Engineering Rheinisch-Westfälische Technische Hochschule Aachen UniversitySchinkelstraße 10Aachen 52062Germany

With the increased use of automotive engine start-stop systems,the numerical prediction and reduction of frictional losses in sliding bearings during starting and stopping procedures has become an important *** engineering practice,numerical simulations of sliding bearings in automotive engines are performed with statistical asperity contact models with empirical values for the necessary surface *** aim of this study is to elucidate the applicability of these approaches for the prediction of friction in sliding bearings subjected to start-stop *** this purpose,the friction performance of sliding bearings was investigated in experiments on a test rig and in transient mixed elasto-hydrodynamic simulations in a multi-body simulation environment(mixed-EHL/MBS).In mixed-EHL/MBS,the extended Reynold’s equation with flow factors according to Patir and Cheng has been combined on the one hand with the statistical asperity contact model according to Greenwood and Tripp and on the other hand with the deterministic asperity contact model according to *** detailed comparison of simulation and experimental results clarifies that the application of statistical asperity contact models with empirical values of the necessary inputs leads to large deviations between experiment and *** actual distribution and position of surface roughness,as used in deterministic contact modelling,is necessary for a reliable prediction of the frictional losses in sliding bearings during start-stop operation.

关键词： sliding bearing friction wearing-in contact model,mixed elasto-hydrodynamic simulation

Recapturing meaning: Toward a new material-based design theory for architecture

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Frontiers of Architectural Research 2022年第4期11卷 609-617页

作者： christopher Bardt Faculty of Architecture Rhode Island School of DesignRhode IslandUSA

Architects and students of architecture today are less physically engaged with modeling and drawing representations of proposed things and increasingly rely on digital means and methods that are transforming their embodied interactions with actual materials. The result is that meaning, which makes architecture so central to our cultures, is being diminished. It is being replaced by a misplaced belief that "better" buildings and architecture result from increased use of digital tools. To recapture meaning will require a new design theory for architecture that builds on material engagement theory and the critical role of resistance and sensuous reasoning in the design process, which material has historically provided.

关键词： Architecture Design Material engagement Material-based design Meaning Digital tools

Amplitude Variation with Offset Responses Modeling Study of Walkaway Vertical Seismic Profile Data at CO_2 Geological Storage Site,Ketzin,Germany

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Acta Geologica Sinica(English Edition) 2011年第5期85卷 1118-1126页

作者： Sayed Hesammoddin KAZEMEINI christopher JUHLIN Department of Earth Sciences Uppsala University

An important component of any CO_2 sequestration project is seismic monitoring for tracking changes in subsurface physical properties,such as velocity and *** reservoirs have different amplitude variation with offset(AVO) responses,which can define underground conditions. In the present paper we investigate walkaway vertical seismic profile(VSP) AVO response to CO_2 injection at the Ketzin site,the first European onshore CO_2 sequestration pilot study dealing with research on geological storage of CO_***,we performed rock physics analysis to evaluate the effect of injected CO_2 on seismic velocity using the Biot-Gassmann *** the basis of this model,the seismic response for different CO_2 injection saturation was studied using ray tracing *** then created synthetic walkaway VSP data,which we then *** contrast,synthetic seismic traces were created from borehole ***,we found that the amplitude of CO_2 injected sand layer with different gas saturations were increased with the offset when compared with the original brine target *** is the typical classⅢAVO anomaly for gas sand *** AVO responses matched the synthetic seismic traces very ***,walkaway VSP AVO response can monitor CO_2 distribution in the Ketzin area.

关键词： CO_2 injection rock physics amplitude variation with offset walkaway vertical seismic profile seismic modeling

Jet flows from bubbles during subcooled pool boiling on micro wires

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Science China(Technological Sciences) 2005年第4期48卷 385-402页

作者： D. M. christopher Laboratory of Phase Change and Interfacial Transport Phenomena Department of Thermal Engineering Tsinghua University Beijing 100084 China

An experimental investigation was conducted on subcooled nucleate boiling on ultra-small wires having diameters of 25―100 μm. High-speed photography and laser PIV (Particle Image Velocimetry) technology were used to visually observe the bubble dynamics. For highly subcooled boiling at moderate heat fluxes, the bubbles generally remained attached to the micro heating wires and bubble-top jet flows were clearly observed. Smaller bubbles usually had stronger bubble-top jet flows, while larger bubbles seemed to produce multi-jet flows. The structures of the bubble-top jet flows, as well as multi-jet flows, were proposed from the experimental observation. A model was developed to describe jet flow phenomena from bubbles on micro wires. Numerical simulations for bubbles having diameter of 0.03 and 0.06 mm showed that both the bubble-top and multi-jet flows were induced by a strong Marangoni effect due to high temperature gradients near the wire. The predicted velocity magnitudes and flow structures agreed very well with experimental measurements. The bubble size relative to the wire is an important factor affecting the jet flow structure. For a 0.03 mm bubble on a 0.1 mm wire, only a bubble-top jet flow forms, while a complex multi-jet flow pattern forms around the bubble with a weak bubble-top jet and two side jet flows for a 0.06 mm bubble.

关键词： subcooled boiling, bubble, multi-jet, jet flow, PIV, Marangoni, CFD.