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Preliminary rib support requirements for solid coal ribs using a coal pillar rib rating(CPRR)

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International Journal of mining Science and Technology 2021年第1期31卷 15-22页

作者： Khaled mohamed mark Van Dyke Gamal Rashed morgan msears Robert Kimutis National Institute for Occupational Safety and Health Pittsburgh Mining Research DivisionPittsburghPA 15236USA

Researchers from the National Institute for Occupational Safety and Health(NIOSH)are developing a coal pillar rib rating(CPRR)technique to measure the integrity of coal *** CPRR characterizes the rib composition and evaluates its impact on the inherent stability of the coal *** CPRR utilizes four parameters:rib homogeneity,bedding condition,face cleat orientation with respect to entry direction,and rib *** these parameters are measurable in the field.A rib data collecting procedure and a simple sheet to calculate the CPRR were *** developed CPRR can be used as a rib quality mapping tool in underground coal mines and to determine the potential of local rib instabilities and support requirements associated with overburden *** calculations were conducted for 22 surveyed solid coal ribs,mainly composed of coal *** on this study,the rib performance was classified into four categories.A preliminary minimum primary rib support density(PRSD)line was obtained from these surveyed *** sample cases are presented that illustrate the data collection form and CPRR calculations.

关键词： Coal rib stability Rib support design Coal pillar rib rating Rib quality mapping CPRR Coal classification

Design concerns of room and pillar retreat panels

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International Journal of mining Science and Technology 2017年第1期27卷 29-35页

作者： Klemetti Ted m. sears morgan m. Tulu Ihsan B. mining Engineer Ground Control Branch NIOSH Office of Mine Safety and Health ResearchPittsburghPAUSA

Why do some room and pillar retreat panels encounter abnormal conditions？ What factors deserve the most consideration during the planning and execution phases of mining and what can be done to mitigate those abnormal conditions when they are encountered7 To help answer these questions, and to determine some of the relevant factors influencing the conditions of room and pillar （R ＆ P） retreat min- ing entries, four consecutive R ＆ P retreat panels were evaluated. This evaluation was intended to rein- force the influence of topographic changes, depth of cover, multiple-seam interactions, geological conditions, and mining geometry. This paper details observations were made in four consecutive R ＆ P retreat panels and the data were collected from an instrumentation site during retreat mining. The pri- mary focus was on the differences observed among the four panels and within the panels themselves. The instrumentation study was initially planned to evaluate the interactions between primary and secondary support, but produced rather interesting results relating to the loading encountered under the current mining conditions. In addition to the obse^ation and ｜ll^trumentation, numerical modeling was per- formed to evaluate the stress condi~!ons. Both the Lamodel 3.0 and Rocscience Phase 2 programs were used to evaluate these four panels, The results of both models indicated a drastic reduction in the vertical stresses experienced in these panels due to the full extraction mining in overlying seams when compared to the full overburden load. Both models showed a higher level of stress associated with the outside entries of the panels. These results agree quite well with the observations and instrumentation studies performed at the mine. These efforts provided two overarching conclusions concerning R ＆ P retreat mine planning and execution. The first was that there are four areas that should not be overlooked during R ＆ P retreat mining： topographic relief, multiple^seaPa str

关键词： Room and pillar Retreat mining Deep coverSafety multiple seam

Geotechnical considerations for concurrent pillar recovery in close-distance multiple seams

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International Journal of mining Science and Technology 2018年第1期28卷 21-27页

作者： Peter Zhang Berk Tulu morgan sears Jack Trackemas Ground Control Branch NIOSHPittsburgh Mining Research Division Department of mining Engineering West Virginia University

Room-and-pillar mining with pillar recovery has historically been associated with more than 25% of all ground fall fatalities in underground coal mines in the United *** risk of ground falls during pillar recovery increases in multiple-seam mining *** hazards associated with pillar recovery in multiple-seam mining include roof cutters, roof falls, rib rolls, coal outbursts, and floor *** pillar recovery is planned in multiple seams, it is critical to properly design the mining sequence and panel layout to minimize potential seam *** paper addresses geotechnical considerations for concurrent pillar recovery in two coal seams with 21 m of interburden under about 305 m of depth of *** study finds that, for interburden thickness of 21 m, the multiple-seam mining influence zone in the lower seam is directly under the barrier pillar within about 30 m from the gob edge of the upper *** peak stress in the interburden transfers down at an angle of approximately 20°away from the gob, and the entries and crosscuts in the influence zone are subjected to elevated stress during development and *** study also suggests that, for full pillar recovery in close-distance multiple-seam scenarios,it is optimal to superimpose the gobs in both seams, but it is not necessary to superimpose the *** the entries and/or crosscuts in the lower seam are developed outside the gob line of the upper seam,additional roof and rib support needs to be considered to account for the elevated stress in the multiple-seam influence zone.

关键词： Pillar recovery Room-and-pillar Retreat mining multiple seam mining sequence Pillar design

Effect of Laser Injection Seeder on Rotationally Resolved Spectra of Benzonitrile

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Chinese Physics Letters 2010年第8期27卷 77-79页

作者：徐海峰 JOHNSON Philip m. sears Trevor J. Institute of Atomic and molecular Physics 3ilin University~ Changchun 130012 Chemistry Department Stony Brook University Stony Brook NY 11974 USA Department of Chemistry Brookhaven National Laboratory Upton NY 11973 USA

High resolution lasers are necessary to derive the most information from molecular spectra. However, their use uncovers some photophysical processes that compromise the ability to resolve rotational structure. We study the influence of laser optical mode structure on the high resolution spectra of the S1 states of benzonitrile in a supersonic molecular beam using an Ar^＋ pumped cw ring dye laser which is amplified by a pulsed Nd： YA G laser. The latter could be operated either in one optical mode by injecting （seeding） its oscillator with a single mode diode laser, or with many optical modes by not using the seeder. Rotationally resolved lines are obtained when the oscillator of the YAG laser are operated in one single optical mode, but only a continuum is seen when the YAG laser has multiple modes. It is argued that the ac Stark effect is the most probable reason for broadening and blurring the rotational lines.

关键词： OPTICAL detectors INJECTION lasers NITRILES mOLECULAR spectra mOLECULAR beams ND-YAG lasers STARK effect

Low-temperature processing of screen-printed piezoelectric KNbO3 with integration onto biodegradable paper substrates

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microsystems & Nanoengineering 2023年第1期9卷 271-282页

作者： morgan m.monroe LGuillermo Villanueva Danick Briand École Polytechnique Fédérale de Lausanne(EPFL) Soft Transducers LaboratoryInstitute of Mechanical Engineering2000NeuchâtelSwitzerland École Polytechnique Fédérale de Lausanne(EPFL) Advanced NEMS LaboratoryInstitute of Mechanical Engineering1015LausanneSwitzerland

The development of fully solution-processed,biodegradable piezoelectrics is a critical step in the development of green electronics towards the worldwide reduction of harmful electronic ***,recent printing processes for piezoelectrics are hindered by the high sintering temperatures required for conventional perovskite fabrication ***,a process was developed to manufacture lead-free printed piezoelectric devices at low temperatures to enable integration with eco-friendly substrates and electrodes.A printable ink was developed for screen printing potassium niobate(KNbO3)piezoelectric layers in microns of thickness at a maximum processing temperature of 120℃ with high *** parallel plate capacitor and cantilever devices were designed and manufactured to assess the quality of this ink and evaluate its physical,dielectric,and piezoelectric characteristics;including a comparison of behaviour between conventional silicon and biodegradable paper *** printed layers were 10.7–11.2μm thick,with acceptable surface roughness values in the range of 0.4-1.1μ*** relative permittivity of the piezoelectric layer was *** poling parameters were optimised for the piezoelectric response,with an average longitudinal piezoelectric coefficient for samples printed on paper substrates measured as d33,eff,paper=13.57±2.84 pC/N;the largest measured value was 18.37 pC/N on paper *** approach to printable biodegradable piezoelectrics opens the way forward for fully solution-processed green piezoelectric devices.

关键词： KNbO3 piezoelectric integration

Initial impacts of rain gardens＇ application on water quality and quantity in combined sewer： field-scale experiment

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Frontiers of Environmental Science & Engineering 2017年第4期11卷 127-138页

作者： Isam Alyaseri Jianpeng Zhou Susan m. morgan Andrew Bartlett Department of Civil Engineering Al-Muthanna University Alsamawah Al-Muthanna 72001 Iraq Department of Civil Engineering Southern Illinois University Edwardsville Edwardsville IL 62026 USA Graduate School Southern Illinois University Edwardsville Edwardsville IL 62026 USA Agricultural Statistics Laboratory University of Arkansas Fayetteville AR 72701 USA

Green infrastructures such as rain gardens can benetit onsite reduction ot stormwater runott, leading to reduced combined sewer overflows. A pilot project was conducted to evaluate the impact of rain gardens on the water quality and volume reduction of storm runoff from urban streets in a combined sewer area. The study took place in a six-block area on South Grand Boulevard in St. Louis, missouri. The impact was assessed through a comparison between the pre-construction （2011/2012） and the post-construction （2014） phases. Shortly after the rain gardens were installed, the levels of total suspended solids, chloride, total nitrogen, total phosphorous, zinc, and copper increased. The level of mercury was lower than the detection level in both phases. E. coli was the only parameter that showed statistically significant decrease following the installation of rain gardens. The likely reason for initial increase in monitored water quality parameters is that the post-construction sampling began after the rain gardens were constructed but before planting, resulted from soil erosion and wash-out from the mulch. However, the levels of most of water quality parameters decreased in the following time period during the post-construction phase. The study found 76% volume reduction of stormwater runoff following the installation of rain gardens at one of studied sites. Statistical analysis is essential on collected data because of the encountered high variability of measured flows resulted from low flow conditions in studied sewers.

关键词： Rain gardens Bioretention Combined sewer Stormwater quality and quantity

Choledochal cysts: Similarities and differences between Asian and Western countries

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World Journal of Gastroenterology 2019年第26期25卷 3334-3343页

作者： George N Baison morgan m Bonds William S Helton Richard A Kozarek Digestive Disease Institute Virginia Mason Medical Center

Choledochal cysts(CCs)are rare bile duct dilatations,intra-and/or extrahepatic,and have higher prevalence in the Asian population compared to Western *** of the current literature on CC disease originates from Asia where these entities are most *** are thought to arise from an anomalous pancreaticobiliary junction,which are congenital anomalies between pancreatic and bile *** similarities in presentation between Eastern and Western patients exist such as female predominance,however,contemporary studies suggest that Asian patients may be more symptomatic on *** though CC disease presents with an increased malignant risk reported to be more than 10%after the second decade of life in Asian patients,this risk may be overstated in Western *** this difference in cancer risk,management guidelines for all patients with CC are based predominantly on observations reported from Asia where it is recommended that all CCs should be excised out of concern for the presence or development of biliary tract cancer.

关键词： Choledochal cyst Cholangiocarcinoma Asian populations Western populations Anomalous pancreaticobiliary junction

LIQUID CRYSTAL BASED ROTATING ORTHOGONAL POLARIZATION ImAGING SYSTEm

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Journal of Innovative Optical Health Sciences 2009年第3期2卷 245-251页

作者： QUN ZHU IAN m.STOCKFORD JOHN A.CROWE STEPHEN P.morgan School of Electrical and Electronic Engineering University of Nottingham University Park NottinghamUK NG72RD

Rotating orthogonal polarization imaging provides images of the polarization properties of scattering media which are free from surface *** the technique has been demonstrated using manually rotated Glan–Thompson polarizers to control and analyze the polarization state of the light entering and emerging from the *** paper describes a system that performs these functions using liquid crystal *** system is tested using a polarizing target embedded within a scattering medium and is compared with monte Carlo *** results compare well with those obtained with manual rotation of *** liquid crystal based approach has advantages over the previous system in terms of ease of use,speed,and repeatability and is therefore an important step towards taking the technique into routine clinical use.

关键词： Liquid crystal polarization orthogonal surface reflection scattering tissue.

Luminescence of Er^(3+) in Oxyfluoride Transparent Glass-Ceramics

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Journal of Rare Earths 2006年第6期24卷 699-705页

作者： Akira Ueda Steven H morgan Richard mu Department of Physics Fisk University NashvilleTN 37208 USA

Erbium doped silicate, germanate, and tellurium-germanate oxyfluoride glasses were prepared in a bulk form. Through appropriate heat treatment of the as-prepared glasses, transparent glass-ceramics （TGCs） were obtained with the formation of β-PbF2：Er^3＋ nanocrystals in the glass matrix were confirmed by X-ray ***-defined diffraction peaks were observed in the samples after heat-treatment. The average crystal diameter of these precipitated crystals from full-width at half-maximum （FWHm） of the diffraction peak was estimated to be between 8 and 13 nm. Optical absorption, photoluminescence, and upconversion luminescence were measured on as-prepared glass and glass-ceramics. Luminescence spectra in the TGC samples revealed well-resolved, sharp stark-splitting peaks, which indicates that a majority of Er^3＋ ions has been incorporated into the crystalline phase of the nanocrystals. The intensity of the visible and near infrared luminescence mostly increases in TSG compared to that in the as-prepared glass. In 1.53 μm absorption and emission bands, the maximum absorption peak is blue-shifted from 1531 to 1507 nm, whereas the maximum emission peak is redshifted from 1535 to 1543 nm in TGC, as compared with that in glass. The bandwidth at half-maximum （BWHm） of the emission band is significantly broader in TGC than in glass, which is beneficial to the erbium-doped fiber amplifier （EDFA）. Upconversion luminescence was measured using 800 nm near-infrared light excitation. Drastically increased upconversion 1 was observed from the TGC as compared to that from their corresponding as-prepared glasses. In addition to a strong green emission centered at 545 nm because of ^4S3/2→^4I15/2 transition and a weaker red emission centered at 662 nm because of ^4F9/2→^4I15/2 transition, generally seen from the Er^3＋ doped glasses, two violet emissions centered at 410 nm because of ^2H9/2→^4I15/2 transition and centered at 379 nm because of ^4G11/2→^4I15/2 transition were also o

关键词： luminescence transparent glass-ceramics rare earths