• Title/Summary/Keyword: GER

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Coordinated supporting method of gob-side entry retaining in coal mines and a case study with hard roof

  • Liu, X.S.;Ning, J.G.;Tan, Y.L.;Xu, Q.;Fan, D.Y.
    • Geomechanics and Engineering
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    • v.15 no.6
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    • pp.1173-1182
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    • 2018
  • The coal wall, gob-side backfill, and gangues in goaf, constitute the support system for Gob-side entry retaining (GER) in coal mines. Reasonably allocating and utilizing their bearing capacities are key scientific and technical issues for the safety and economic benefits of the GER technology. At first, a mechanical model of GER was established and a governing equation for coordinated bearing of the coal-backfill-gangue support system was derived to reveal the coordinated bearing mechanism. Then, considering the bearing characteristics of the coal wall, gob-side backfill and gangues in goaf, their quantitative design methods were proposed, respectively. Next, taking the No. 2201 haulage roadway serving the No. 7 coal seam in Jiangjiawan Mine, China, as an example, the design calculations showed that the strains of both the coal wall and gob-side backfill were larger than their allowable strains and the rotational angle of the lateral main roof was larger than its allowable rotational angle. Finally, flexible-rigid composite supporting technology and roof cutting technology were designed and used. In situ investigations showed that the deformation and failure of surrounding rocks were well controlled and both the coal wall and gob-side backfill remained stable. Taking the coal wall, gob-side backfill and gangues in goaf as a whole system, this research takes full consideration of their bearing properties and provides a quantitative basis for design of the support system.

Cloning, Expression, and Biochemical Characterization of dTDP-Glucose 4,6-Dehydratase Gene (gerE) from Streptomyces sp. GERI-155

  • Lee, Hei-Chan;Sohng, Jae-Kyung;Kim, Hyung-Jun;Nam, Doo-Hyun;Seong, Chi-Nam;Han, Ji-Man;Yoo, Jin-Cheol
    • Journal of Microbiology and Biotechnology
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    • v.14 no.3
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    • pp.576-583
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    • 2004
  • GERI-155 is a macrolide antibiotic containing two deoxyhexose molecules and shows antimicrobial activities against Gram-positive bacteria. Deoxysugar biosynthetic gene cluster of GERI-155 from Streptomyces sp. GERI-l55 genome was cloned. Four orfs were identified and a putative orf presumed to be the dTDP g]ucose-4,6-dehydratase gene was designated as gerE. GerE was expressed in E. coli by using a recombinant expression vector pHJ1. The expressed protein was purified from E. coli cell lysate by using ammonium sulfate fractionation, and DEAE-sepharose CL-6B and hydroxylapatite column chromatography. The molecular mass of the expressed protein correlated with the predicted mass that was deduced from the cloned gene sequence data. The recombinant protein was a homodimer with a subunit relative molecular weight of 39,000 Dalton. It was found to have dTDP-glucose 4,6-dehydratase activity and also found to be highly specific for dTDP-glucose as a substrate. The values of $K_{m} and V_{max}$ for dTDP-g]ucose were $32\mu$M and 335 nmol $min^{-1}$ (mg protein)^{-1}$, respectively. dTTP and dTDP were strong inhibitors of the protein. $NAD^+$, the coenzyme for dTDP-glucose 4,6-dehydratase, was tightly bound to the expressed protein.

On the Reliability of the Computational Fire Model Based on the Yield Rate Concept of Combustion Gases (생성율 개념에 기초한 화재모델의 신뢰성에 대한 연구)

  • Kim, Sung-Chan;Ko, Gwon-Hyun;Lee, Seong-Hyuk
    • Fire Science and Engineering
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    • v.23 no.4
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    • pp.130-136
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    • 2009
  • The present study has been performed to evaluate the reliability of the fire field model (FDS version 5.2) with yield rate concept of combustion products. The CO and smoke density predicted by FDS model was directly compared with measurement in a reduced scale ISO-9705 room. The GER (global equivalence ratio) concept was used to characterize the CO and smoke density with ventilation condition in the fire compartment. The FDS model tends to under-predict CO concentration and smoke density than those of measurement for the under-ventilated conditions. Also, the discrepancy between predicted and measured result increases as GER increases. In order to improve the reliability of the fire model for performance evaluation of fire safety, the fire model is necessary to be validated in various fire cases as well as develop detailed physical model.

Computed tomographic features of gastric and esophageal content in dogs undergoing CT myelography and factors influencing the presence of esophageal fluid

  • Benzimra, Caroline;Cerasoli, Ilaria;Rault, Delphine;Chalvet-Monfray, Karine;Cauvin, Eddy;Couturier, Laurent;Gatel, Laure
    • Journal of Veterinary Science
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    • v.21 no.6
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    • pp.84.1-84.11
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    • 2020
  • Background: Gastroesophageal reflux (GER) has been reported to be a common finding in dogs under general anesthesia. Objectives: The aim of this retrospective study was to assess the esophageal and gastric contents in a population of dogs undergoing computed tomographic myelography (myeloCT) examination and to evaluate the factors influencing the presence of esophageal fluid (gastric content, duration of anesthesia, body position, and intrinsic factors). Methods: Esophageal and gastric contents of 83 non-brachycephalic dogs were retrospectively assessed based on plain and myelo-CT scans. Age, weight, breed, sex, and the time between the 2 computed tomography [CT] scans were included. Results: Esophageal fluid was present in 19% (16/83) of the animals, and 14% (12/83) and 46% (37/83), respectively, had fluid or food material in their stomachs. The frequency of observing esophageal fluid on myelo-CT scans was significantly increased compared with plain CT scans (p = 0.006). The presence of gastric fluid was significantly associated with an increased frequency of observing esophageal fluid compared to other gastric contents (p = 0.049; odds ratio, 3.1). The presence of esophageal fluid was not correlated with alimentary gastric contents (p = 0.17). Increased body weight and duration of anesthesia were significantly associated with an increased frequency of observing esophageal fluid (p = 0.022, p = 0.021). Conclusions: Unlike alimentary gastric contents, fluid gastric contents were correlated with the presence of esophageal fluid upon myelo-CT. The observation of fluid in the esophagus may be consistent with GER. This study provides data additional to pH monitoring studies of GER and may support previous studies recommending shorter pre-anesthetic fasting periods in dogs.

Stability analysis of roof-filling body system in gob-side entry retained

  • Jinlin Xin;Zizheng Zhang;Weijian Yu;Min Deng
    • Geomechanics and Engineering
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    • v.36 no.1
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    • pp.27-37
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    • 2024
  • The roof-filling body system stability plays a key role in gob-side entry retained (GER). Taking the GER of the 1103 belt transportation roadway in Heilong Coal Mine as engineering background, stability analysis of roof-filling body system was conducted based on the cusp catastrophe theory. Theoretical results showed that the current design parameters of 1103 belt transportation roadway could ensure the roof-filling body system stable during the resistance-increasing support stage of the filling body and the stable support stage of the filling body. Moreover, a verified global numerical model in FLAC3D was established to analyze the failure characteristics including surrounding rock deformation, stress distribution, and plastic zone. Numerical simulation indicated that the width-height ratio of the filling body had a great influence on the stability of the roof-filling body system. When the width-height ratio was greater than 0.62, with the decrease of the width-height ratio, the peak stress of the filling body gradually decreased; when the width-height ratio was greater than 0.92, as the distance to the roadway increased, the roof stress increased and then decreased. The theoretical analysis and numerical simulation findings in this study provide a new research method to analyze the stability of the roof-filling body system in GER.

Study on the Prevention and Combat System of Oil Pollution in Germany (독일의 해상유류오염 예방 및 방제체계 고찰)

  • Shin, Ok-Ju
    • Journal of Environmental Policy
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    • v.8 no.1
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    • pp.97-127
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    • 2009
  • In Germany, North Sea and East Sea possess significant meaning in many aspects. North coast has an important economical significance to North Sea Gulf States. There are a number of harbors and manufacturing facilities in this area. Agriculture is also developed. East sea, where sea water and river water mingle. has a problem that it can not control harmful substances as fast as the North Sea due to its geographical location of being connected with the North Sea as a narrow water. To protect from big and small ship accidents and pollution sources, East Sea and North Sea have enacted HELKOM Convention and OSPAR Convention, respectively. Moreover, Denmark and Germany have made cooperation on tugboats in the occurrence of shipment accidents through the LethGer-Plan and DenGer-Plan. In 1998, after the Pallas accident that occurred near Bremen, the need to improve cooperation among each states on usable resources for ocean security has been increased in Germany. Consequently, the federal government and gulf state governments associated and organized the so called, "Havarie-Kommanando Ship Accident Measure Unit". Haravarie-Kommanando is a federal-state associated organization that deals with affairs that controls national operation and mobilization of ship accident related organizations unitively when serious ship accidents occur. Moreover, federal and state participant organizations, each shipping agencies and Wiking-Helicopers-Services, a helicopter agency, are cooperating well. Also, mutual assistance with the most prominent passenger agency called Scandlines, ARGE Kuestenschutz(Germany-Denmark shipping agency) is making progress as well.

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Supplementary Effect of the Giant Embryonic Rice on Serum and Heaptic Lipid Levels of Streptozotocin-induced Diabetic Rats (Streptozotocin 유발 당뇨 쥐의 거대배아미 식이에 의한 혈액 및 간조직의 지질조성)

  • Lee, Youn-Ri;Kim, Chae-Eun;Nam, Seok-Hyun;Kang, Mi-Young
    • Korean Journal of Food Science and Technology
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    • v.38 no.4
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    • pp.562-566
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    • 2006
  • This study was carried out to investigate the supplementary effects of giant embryonic rice, which has over two times of embryo size compared the normal rice, on lipid metabolism of insulin dependent diabetic rats. Streptozotocin induced diabetic rats were fed four kinds of experimental diets com starch diet as a control (C-D), a polished rice diet (R-D), a brown rice diet (BR-D) and a giant embryonic rice diet (GER-D) respectively, for 6 weeks. Diet intake body weight, organ weights and lipid levels of serum, liver and feces were measured. There was significant difference in diet intake and body weight among experimental groups. The concentrations of serum triglyceride and total serum cholesterol of BR-D and GER-D groups were lower than those of others. The total hepatic cholesterol level was the lowest in GER-D group. The contents of total lipid and total cholesterol excreted in feces of BR-D and GER-D groups were higher than those of C-D and R-D groups. These results suggested the giant embryonic rice diets can effectively reduce serum triglyceride level and total hepatic cholesterol level in insulin dependent diabetic rats, and hypolipidemic effects be due to increasing fecal lipid excretion.