• Title/Summary/Keyword: WA

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A Comparison of the Cooling Effects for the Compressed Cold Air and Coolant on the Cylindrical Grinding with WA Wheel (WA 숫돌을 이용한 원통 연삭 시 압축냉각공기와 연삭유의 냉각효과에 관한 연구)

  • Lee, Seok-Woo;Choi, Hon-Zong;Jeong, Hae-Do
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.10
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    • pp.155-161
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    • 2000
  • Recently, environmental pollution has become a big problem in industry and many researches have been done in order to preserve the environment. In the grinding process, the coolant has great influence on environment. It contains several chemicals(sulfur, phosphorus and chlorine) to improve the grinding efficiency. If these additives go into the workplace atmosphere, it is harmful for workers. It can also cause the environment pollution. Because of these reasons many studies have been done to minimize the amount of coolant. However the small amount of coolant can cause the thermal defect on the ground surface layer. This study forced the effects of the compressed cold air when the spindle shaft materials(SCM4 & SCM21) were cylindrical ground with WA wheel. The compressed cold air was used as the coolant and grinding performance was compared with that of the conventional grinding fluids(emulsion). Many experiments were carried out with these two cooling materials. The surface roughness, residual stress, and roundness were measured for the cylindrical grinding. The test results showed that the compressed cold air was very useful as the cooling materials for grinding process. It was also efficient to minimize the thermal defects of workpiece and could also play a role in solving environmental pollution.

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Performance Verification of Psudolite-based Augmentation System Using RF signal logger and broadcaster (RF 신호 수집/방송 장치를 활용한 의사위성 기반 광역보정시스템의 후처리 성능 검증)

  • Han, Deokhwa;Yun, Ho;Kee, Changdon
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2014.06a
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    • pp.103-104
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    • 2014
  • Wide Area Differential GNSS(WA-DGNSS) was developed in order to improve the accuracy and integrity performance of GNSS. In Korea, WA-DGNSS development project, which aims to develop core algorithms and verify the performance using pseudolite-based demo system, is currently in progress. In this paper, overall structure of developed system and experimental methods which enables the post-processing test with commercial receiver will be described. In this system, pseudolite is used to broadcast augmenting signal and RF signal logger and broadcaster were used to test the performance. Performance test was conducted broadcasting the logged RF signal and pseudolite signal to commercial receiver and those results will be described.

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Study on Early Adhesive Characteristic of Chip Seals Using a Surface Energy Approach (표면 에너지 원리를 이용한 칩실 포장의 초기 점착력 특성 연구)

  • Im, Jeong Hyuk
    • International Journal of Highway Engineering
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    • v.17 no.6
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    • pp.47-54
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    • 2015
  • PURPOSES : The objective of this study is to evaluate the early adhesive characteristic of asphalt emulsions, including polymer-modified emulsions, for chip seals using the surface energy concept, the bitumen bond strength (BBS) test, and the Vialit test. METHODS : Two general methods, the BBS test and Vialit test, were applied to investigate the bond strength and the aggregate loss, respectively. A new theory, the surface free energy (SFE) theory, was used to evaluate the adhesive characteristic between the emulsion and the aggregate. Based on the theory, the contact angles were measured, and then the surface energy components were calculated. Using those components, the work of adhesion (Wa) was calculated for each emulsion. To ensure reliable results, all the tests were performed under the same conditions, i.e., at $25^{\circ}C$ for 240 minutes of curing time. For the materials, three emulsions (CRS-2, CRS-2L, and CRS-2P) and one aggregate type (granite) were employed. RESULTS AND CONCLUSIONS : Under the same conditions, the modified emulsions showed better adhesive characteristics and curing behaviors than the unmodified emulsions. In addition, there was no significant difference between the various modified emulsions. One of the important findings is that the analysis by Wa presents more sensitive results than other methods. The results of the Wa showed that the CRS-2P emulsion has the best adhesive characteristics. Consequently, the use of modified emulsions for chip seals could prevent aggregate loss and allow open traffic earlier.

Cultural Characteristics and Ascospore Density in Soil of Monosporascus Cannonballus on Cucurbitaceae Plants (박과류 검은점뿌리썩음병균의 배양적 특성 및 토양내 자낭포자 밀도)

  • 허노열;류경열;이용범
    • Research in Plant Disease
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    • v.7 no.1
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    • pp.16-19
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    • 2001
  • The cultural caracteristics of Monosporascus cannonballus causing root rot of Cucurbitaceae plants were examined in vitro, and population density of the fungal ascospores were measured and compared aoming diferent host species and soil depths. Potato-dextrose agar(PDA) was the most appropriate medium for the mycelial growth and perithecial formation among the 5 media tested. Corn-meal agar(CMA), oat-meal agar (OMA) and V-8 juice agar were moderate media for the mycelial growth and perithecial formation, whereas water agar(WA) was poor medium. Perithecia were not formed on WA. Optimum temperature for the formation of perithecia was about 25 to 30$^{\circ}C$. distribution of ascospores in the infested fields was variable amount the curcubitaceae plants and within the same plant species, ranging from 1.7 to 14.6 ascospores in 20 g of soil, but no ascospore was detected in the uninfested field soils. Ascospores were distributed more at 20cm of soil depth than at 10cm or 30cm of soil depth.

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Moisture Concentration Variation of Silages Produced on Commercial Farms in the South-Central USA

  • Han, K.J.;Pitman, W.D.;Chapple, A.
    • Asian-Australasian Journal of Animal Sciences
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    • v.27 no.10
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    • pp.1436-1442
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    • 2014
  • Preservation of forage crops as silage offers opportunity to avoid the high risk of rain-damaged hay in the humid south-central USA. Recent developments with baled silage or baleage make silage a less expensive option than typical chopped silage. Silage has been important in the region primarily for dairy production, but baleage has become an option for the more extensive beef cattle industry in the region. Silage samples submitted to the Louisiana State University Agricultural Center Forage Quality Lab from 2006 through 2013 were assessed for dry matter (DM) and forage nutritive characteristics of chopped silage and baleage of the different forage types from commercial farms primarily in Louisiana and Mississippi. Of the 1,308 silage samples submitted, 1,065 were annual ryegrass (AR) with small grains (SG), the warm-season annual (WA) grasses, sorghums and pearl millet, and the warm-season perennial (WP) grasses, bermudagrass and bahiagrass, providing the remaining samples. Concentration of DM was used to indicate an effective ensiling opportunity, and AR silage was more frequently within the target DM range than was the WA forage group. The AR samples also indicated a high-quality forage with average crude protein (CP) of 130 g/kg and total digestible nutrient (TDN) near 600 g/kg. The cooler winter weather at harvest apparently complicated harvest of SG silage with chopped SG silage lower in both CP and TDN (104 and 553 g/kg, respectively) than either AR silage or baleage of SG (137 and 624 g/kg for CP and TDN, respectively). The hot, humid summer weather along with large stems and large forage quantities of the WA grasses and the inherently higher fiber concentration of WP grasses at harvest stage indicate that preservation of these forage types as silage will be challenging, although successful commercial silage samples of each forage type and preservation approach were included among samples of silages produced in the region.

Aetiopathogenesis and clinical features of dysmenorrhoea (Usr-i-tamth) in traditional Unani medicine and contemporary era: A literary research

  • Sultana, Arshiya;Khan, Asma;Quwat Nawaz, Qhuddsia;Syed, Lamatunoor
    • CELLMED
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    • v.6 no.1
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    • pp.4.1-4.7
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    • 2016
  • Dysmenorrhoea is the most important under diagnosed and undertreated gynaecologic disorder of all menstrual complaints. It affects 50% women of childbearing age and has a major impact on health and societal costs worldwideespecially in developing countries. Therefore, a literary exploration of traditional sources for aetiopathogenesis and clinical features of usr-i-tamth (dysmenorrhoea) were reviewed to correlate with contemporary knowledge.The traditional Unani sources viz., Al Hawi fi'l Tibb (Continens Liber),Tarjuma Kamil al-Sana'a al-Tibbiyya, Al-Qanun fi'l Tibb (Canon of Medicine), Dhakhira Khawarizam Shahi, Tibb-i-Akbar, Iksir-i-A'zam, Kitab al-Kulliyyat, and Kulliyyat-i-Qanun were reviewed. Further, recent studies in the contemporary era were also browsed on the website. The causes of usre-i-tamth as per classical sources are distemperament, uterine diseases (atresia, inflammation, amenorrhoea, cancer, prolapse, ulcer, tenuous morbid matter, and cervical obstruction), psychological disturbances, environmental factors, menstrual irregularities, obesity and young age. Recent studies also prove that obesity, psychological disturbance, menstrual irregularities, environmental factors, uterine diseases and young age lead to dysmenorrhea.Unani classical sources are very much enriched with the informative knowledge related to menstruation and uterine pain/dysmenorrhoea and recent studies in contemporary proves the same. Hence, implementation of the traditional system of medicines in present-day era may play a vital role to restore health in a holistic way.

Ion Exchange of Ultrafiltrated Soybean Cooking Water for the Production of Soy-oligosaccharides (대두올리고당 생산을 위한 한외여과 대두침출액의 이온교환)

  • Ku, Kyung-Hyung;Park, Dong-June;Mok, Chul-Kyoon
    • Korean Journal of Food Science and Technology
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    • v.27 no.3
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    • pp.313-317
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    • 1995
  • Ion exchange process was optimized to purify ultrafiltrated bean cooking water(BCW) for the production of soy-oligosaccharides. The ultrafiltrated BCW with cutoff MW(COMW) 20,000 membrane was treated with various ion exchange resins. Protein and ash were mostly removed by anion and cation exchange resins, respectively. Based upon removing capabilities for ash and protein, a cation exchange resin(SK1B) and an anion exchange resin(WA30) were selected. Protein and ash were more efficiently removed at low extract/resin ratios(ERR), but part of the oligosaccharides were concomitantly lost. When 2-step-ultrafiltrated BCW first with COMW 20,000 membrane and successively with COMW 5,000 membrane was treated with a mixed resin(SK1B : WA30 =1 : 2) at ERR 5.0, most oligosaccharides were recovered in a clear protein- and ash-free liquid.

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