• Title/Summary/Keyword: Hemp

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Effective Utilization of Hemp Fiber for Pulp and Papermaking(II) - Characteristics of hemp-wood paper made of hemp fiber cooked at low temperature - (펄프.제지용 원료로서의 삼 섬유 이용에 관한 연구(제2보) -저온 펄프화 삼 섬유의 수초지 특성-)

  • Lee, Myoung-Ku;Kim, Ji-Seop;Yoon, Seung-Lak
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.43 no.5
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    • pp.27-33
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    • 2011
  • Hemp bast pulp cooked at temperature below $100^{\circ}C$ followed by defibration by the knife and the valley beater, respectively was mixed with softwood pulp varying the amount of hemp pulp in order to find the optimum condition for making hemp-wood paper. Both the knife and the valley beaters contributed to the dispersion of pulp fiber well. Lots of shives were found when the knife beater was applied exclusively, but the fibers were dispersed well when freeness dropped to 600 mL CSF and 500 mL CSF by the valley beater. Air resistance decreased drastically below 500 mL CSF where rapid disrupture of pulp fiber occurred. As the values for freeness and hemp fiber content increased, so did roughness and bulk. It was apparent that the tear strength of hemp-wood paper was on the rise drastically as hemp fiber content increased. Nevertheless the optimum hemp fiber content of hemp-wood paper would be 20% considering the decrease in both tensile and burst strengths as well as sheet formation.

Research on Hemp Fabrics Produced at Boseong (보성 삼베 연구)

  • 고부자
    • The Research Journal of the Costume Culture
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    • v.12 no.1
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    • pp.168-181
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    • 2004
  • This research on the present state of production and circulation of boseong-sambae, based on the materials, has been collected and arranged through the survey for one you, 2003. Boseong-sambae, the hemp fabric produced at Boseong, hold 35% of nationwide production volume and 50% of circulation volume. The products of hemp include hemp fabrics, shroud, contemporary Korean dresses and other household articles. Dried hemp skin, hemp thread and hemp fabrics are traded at the fair held in every five days, mostly by direct transactions which is trusted between the producers and consumers. A bolt of boseong-sambae includes 20 ja(a Korean foot, 60cm in length) of hemp fabrics in breadth of 35cm. The price of a bolt is approximately 2∼3 hundred thousand won. They are endeavoring to revive hemp fabric that the image was lost due to the cheap and coarse fabrics woven with Chinese thread since the latter half of 1990's. The advanced countries have invested positively in this business because hemp is an environment friendly material. Thus, a strong national support is demanded in this field facing a crisis due to the inundating of coarse hemp products from China, and the aging problem of the initiate, the reason of the discontinuation of the inherited technique. Through this research understanding tire present station and the problem of hemp production, the future research will be followed expecting the Renaissance of the Korean traditional hemp fabrics.

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HEMP Effect Analysis for Equipment Using Comparison of Norms between HEMP Filter Residual Current and Conducted Susceptibility Criteria (HEMP 필터 잔류 전류와 전도 내성 기준의 특성인자 비교를 통한 장비의 HEMP 영향성 분석)

  • Kwon, Joon-Hyuck;Song, Ki-Hwan;Yook, Jong-Gwan
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.25 no.2
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    • pp.199-207
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    • 2014
  • Although High-altitude electromagnetic pulse(HEMP) protection filter meets the requirements of pulsed current injection(PCI) acceptance test, the equipment under test which has low electromagnetic susceptibility level can be damaged during PCI verification test that is performed on operating condition of equipment. This paper proposed the HEMP effect analysis method using comparison of norms between residual current of HEMP filter and transient electromagnetic conducted susceptibility criteria of equipment, as an alternative method under the condition that performing PCI verification test is limited in HEMP hardened facilities. PCI acceptance test of HEMP filter, transient electromagnetic conducted susceptibility test, and PCI verification test are performed and test results are analyzed.

The characteristics and changes of traditional hemp textile production of Gurye at Jeollanam-do in modern times (1920s~1980s) (근대 시기(1920~1980) 전라남도 구례군의 전통 삼베 수공업 생산 방식의 특징과 변화)

  • Choi, Seung Yeun
    • The Research Journal of the Costume Culture
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    • v.22 no.1
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    • pp.16-27
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    • 2014
  • This study investigated the characteristics of and changes in hemp textile production practices at Gurye in Jeollanam-do in modern times. To do this, in this study, both a literature review and fieldwork research were utilized as research methods. The literature review focused on Gurye's hemp data, and the fieldwork research involved two separate trials. Male and Female residents of Gurye who had experience in the area of hemp production from the 1920s to the 1980s participated in this study. The results were as follows. First, regarding hemp fiber cultivation in Gurye, hemp cultivation continued to the 1970s and there were no changes in hemp cultivation practices during the Japanese colonial-era. Second, there have been very important changes in hemp kilns over time. In the 1950s, there were both single-body kilns and separate-body kilns in Gurye. Later, specifically in the 1950s, a new type of kiln using an iron pot appeared, and the most modern kilns were concrete structures. Third, in Gurye, women cooperatively removed hemp husks immediately after stemming, subsequently bleaching the hemp by soaking it in lye or caustic soda. Over time, there have been changes in ash types and in soaking periods. Fourth, loom types changed from the traditional Korean back-strap loom to the treadle loom in the 1930s- to 1940s. Fifth, since the 1970s, the hemp textile output levels of Gurye have been reduced due to the westernization of clothing styles, the inflow of Chinese hemp fiber and government regulations pertaining to hemp cultivation.

Measurement and Analysis of Antenna Induced Voltage for Tactical Mobile Wireless Communication System under HEMP Environment (HEMP 상황 하 전술기동무선통신체계 안테나 유도전압 측정 및 분석)

  • Park, Kyoung-Je;Jeong, Kil-Soo;Kim, Jung-Sup;Park, Yong-Woo;Park, Jae-Hyun
    • Journal of the Korea Society for Simulation
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    • v.30 no.2
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    • pp.33-40
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    • 2021
  • The situation of high-altitude electromagnetic pulses (HEMP) arises from high-altitude nuclear explosions. The HEMP situation can be simulated through the threat level investigation (TLI). In this paper, the induced voltage according to the antenna type of the tactical mobile radio communication system was measured and analyzed by TLI. Under the influence of HEMP, electronic equipment can be paralyzed or damaged. HEMP protection filters are commercially available for power lines and signal lines. However, commercialization of HEMP filters for antennas is insufficient, and even some of them exist for lightning protection. In order to make an appropriate HEMP protection filter according to the frequency and type of the antenna, the induced voltage was measured and the maximum induced voltage was analyzed through extrapolation. It was found that the measured induced voltage decreased as the frequency increased, such as in the HF, VHF and UHF bands of the measurement results.

Analysis of PCI Cable Effects in HEMP Conducted Disturbance (HEMP 전도성 방해 펄스 전류 주입(PCI) 케이블의 영향 분석)

  • Jang, Tae-Heon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.24 no.8
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    • pp.772-780
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    • 2013
  • The high-altitude electromagnetic pulse(HEMP) conducted environment and the HEMP radiated environment are established as the consequences of a high-altitude nuclear explosion. The IEC 61000-2-10, the international standard, defines the HEMP conducted environment. The IEC 61000-5-5 defines how protective devices for conducted disturbance proposed for HEMP protection shall be specified. The IEC 61000-4-24 deals with methods for testing protective devices for HEMP conducted disturbance. The IEC 61000-4-24:1997 mainly describes the measurement method of small protective components. However, it does not provide the measurement method for a combination filter of a protective component and a filter which is widely used in recent. It is important to consider the characteristic of the measurement setup parameters like thickness and length of the cable and its height above ground plane etc. in establishing measurement setup because HEMP conducted disturbances include the frequency spectrum below 50 MHz. This paper deals with the optimized measurement method, considering the frequency spectrum of HEMP conducted disturbance, current waveform, and analyzing the effects of cables existing in the measurement setup.

A Study on the Measurement Method of Test Waveform for System-level HEMP Immunity Test (체계 수준 HEMP 내성 시험을 위한 시험파형 계측 기법 연구)

  • Yeo, Saedong
    • Journal of the Korea Institute of Military Science and Technology
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    • v.22 no.2
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    • pp.233-240
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    • 2019
  • High-altitude ElectroMagnetic Pulse(HEMP) is a high-power electromagnetic pulse caused by nuclear explosions at altitudes above 30 km. This pulse can cause serious damage to the electrical/electronic device. Therefore, there are a lot of studies on the effects of HEMP in the literature. When conducting studies on the effects of HEMP, it is essential to measure the simulated HEMP. Depending on the need for measurement, this paper focuses on the HEMP measurement method. This paper proposes a measurement method using frequency domain compensation to extract the correct waveform and solves the offset problem more efficiently than the conventional methods. The proposed method is verified by experiment using HEMP simulator and measurement system in ADD.

Implementation of Dedicated Power Line Filter for HEMP Protection (HEMP 보호용 전원선 필터 구현)

  • Kim, Keun-Nam;Lee, Sung-Hwa;Kim, Jin-Tae
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.16 no.4
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    • pp.47-52
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    • 2016
  • This paper covers the importance of a dedicated Power Line Filter implementation against HEMP(High altitude ElectroMagnetic Pulse) threats caused by high altitude nuclear detonations. As the PCI test results for E1 short pulse with 2500[A], only HEMP filter obtained the required residual current around 8[A], but others didn't meet below 10[A] on MIL-STD-188-125 PCI regulation. Consequently, the development of a dedicated power line filter turned out to be a essential element in order to protect the power related system against HEMP transient.

A Development of the Optimized Shielding Room Design Simulator for HEMP Protection (HEMP 방호용 차폐실 최적설계를 위한 시뮬레이터 개발)

  • Min, Gyung-Chan;Kim, Dong-Il
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.10 no.4
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    • pp.121-126
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    • 2010
  • Regarding HEMP has been studied as few thousand of paper by major nuclear bomb holding countries with USA for the self protection against nuclear bomb attract. Major HEMP protection facilities are consist of the shielding, filtering, grounding and high voltage protection circuits. Shielding room construction required a highest cost among the key protective facilities. Most of a theoretical formulas listed on the paper and related books has a little correlations in the certain frequency band between the theoretical formulas and field measuring results. For the reasons we proposed the advanced new theoretical formulas and developed the computer simulation S/W as enough as apply to the cost effective shielding room design for HEMP considering the various structural constants.

Densified Pellet Fuel from Woody Core of Industrial Hemp (산업용 대마 목부를 이용한 고밀화 펠릿 연료 제조)

  • Shin, Soo-Jeong;Han, Gyu-Seong;Shim, Hwa-Seob;Ahn, Byeong-Kuk
    • 한국신재생에너지학회:학술대회논문집
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    • pp.221-224
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    • 2008
  • We made densified wood pellet by hemp woody core as replacing wood resource. Hemp was separated into the bast fiber and the woody core by hot steaming treatment. The hemp woody core had a similar lignin content and carbohydrate composition with hardwood. Also, the hemp had a low ash content, which resulted in a low ash formation in pellet burning. Heating value of the hemp pellet had a very similar to the pellet made by hardwoods. The hemp woody core can replace hardwood for densified wood pelletmaking.

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