• Title/Summary/Keyword: LAS

Search Result 356, Processing Time 0.031 seconds

A Study on the Ge Substituted LAS Ceramics Using Metla Alkoxide (금속알콕사이드를 이용한 LAS계 내열세라믹스의 제조시 Ge 성분의 치환에 관한 연구)

  • 장성중;김형태;이응상
    • Journal of the Korean Ceramic Society
    • /
    • v.32 no.11
    • /
    • pp.1233-1240
    • /
    • 1995
  • LAS system, which is difficult to be sintered, was densified by using the powder synthesized from metal alkoxides. Sinterability, thermal and mechanical properties were improved through synthesizing the complex oxide powder from the addition of Ge as an alkoxide. As a result, the synthesizing and sintering temperature of the LAS system lowered by about 10$0^{\circ}C$ and its modulus of rupture (MOR) increased twice higher compared to the sample from the oxide by the direct method.

  • PDF

Effects of Linear Alkylbenzene Sulfonate on Hydrogen Fermentation of Food Waste (음식물류 폐기물의 수소 발효 시 linear alkylbenzene sulfonate의 영향)

  • LEE, CHAE-YOUNG;CHOI, JAE-MIN
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.27 no.5
    • /
    • pp.510-516
    • /
    • 2016
  • This study examines the effects of linear alkylbenzene sulfonate on hydrogen fermentation of food waste. The hydrogen production rate was similar with different linear alkylbenzen sulfonate (LAS) concentrations. The maximum hydrogen yield increased with increasing LAS concentration. The highest maximum hydrogen yield was $0.550{\pm}0.005mol$ H2/mol hexose at LAS for 5.52 mg/L. But the maximum hydrogen yield decreased above LAS for 11.05 mg/L. The concentration of acetate in control reactor was increased, but it decreased with increasing LAS concentration in other reactors.

Studies on the Dynamic Surface Tension of GL12 and Anionic Mixtures (N-Dodecanoyl, N-Methyl Glucamine(GL 12)과 음이온 계면활성제 혼합물의 Dynamic Surface Tension에 관한 연구)

  • Ahn, Ho-Jeong;Choi, Kyu-Suk
    • Applied Chemistry for Engineering
    • /
    • v.7 no.1
    • /
    • pp.101-108
    • /
    • 1996
  • The dynamic surface tension of GL12 (easily biodegradable nonionic surfactant and mild to skin), LAS and SLES aqueous solutions and that of mixed surfactant systems were measured by the maximum bubble pressure method at different mixing ratios. The effects of various salt such as NaCl, CsCl and urea on the dynamic surface tension of mixed surfactant systems were also studied. The dynamic surface tension of GL12 was not influenced by the presence of salts. On the contrary, the dynamic surface tensions of anionic surfactants (LAS and SLES) were significantly affected by the salts. In the mixed surfactant systems, the effect of salt increased as the composition of anionic LAS or SLES increased in the GL12/LAS and GL12/SLES mixtures.

  • PDF

LAS-Derived Determination of Surface-Layer Sensible Heat Flux over a Heterogeneous Urban Area (섬광계를 이용한 비균질 도시 지표에서의 현열속 산정)

  • Lee, Sang-Hyun
    • Atmosphere
    • /
    • v.25 no.2
    • /
    • pp.193-203
    • /
    • 2015
  • A large aperture scintillometer (LAS) was deployed with an optical path length of 2.1 km to estimate turbulent sensible heat flux (${\mathcal{Q}}_H$) over a highly heterogeneous urban area. Scintillation measurements were conducted during cold season in November and December 2013, and the daytime data of 14 days were used in the analysis after quality control processes. The LAS-derived ${\mathcal{Q}}_H$ show reasonable temporal variation ranging $20{\sim}160W\;m^{-2}$ in unstable atmospheric conditions, and well compare with the measured net radiation. The LAS footprint analysis suggests that ${\mathcal{Q}}_H$ can be relatively high when the newly built-up urban area has high source contribution of the turbulent flux in the study area ('northwesterly winds'). Sensitivity tests show that the LAS-derived ${\mathcal{Q}}_H$ are highly sensitive to non-dimensional similarity function for temperature structure function parameter, but relatively less sensitive to surface aerodynamic parameters and meteorological variables (temperature and wind speed). A lower Bowen ratio also has a significant influence on the flux estimation. Overall uncertainty of the estimated daytime ${\mathcal{Q}}_H$ is expected within about 20% at an upper limit for the analysis data. It is also found that stable atmospheric conditions can be poorly determined when the scintillometry technique is applied over the highly heterogeneous urban area.

EVALUATION OF GALVANIC CORROSION BEHAVIOR OF SA-508 LOW ALLOY STEEL AND TYPE 309L STAINLESS STEEL CLADDING OF REACTOR PRESSURE VESSEL UNDER SIMULATED PRIMARY WATER ENVIRONMENT

  • Kim, Sung-Woo;Kim, Dong-Jin;Kim, Hong-Pyo
    • Nuclear Engineering and Technology
    • /
    • v.44 no.7
    • /
    • pp.773-780
    • /
    • 2012
  • The article presented is concerned with an evaluation of the corrosion behavior of SA-508 low alloy steel (LAS) and Type 309L stainless steel (SS) cladding of a reactor pressure vessel under the simulated primary water chemistry of a pressurized water reactor (PWR). The uniform corrosion and galvanic corrosion rates of SA-508 LAS and Type 309L SS were measured in three different control conditions: power operation, shutdown, and power operation followed by shutdown. In all conditions, the dissimilar metal coupling of SA-508 LAS and Type 309L SS exhibited higher corrosion rates than the SA-508 base metal itself due to severe galvanic corrosion near the cladding interface, while the corrosion of Type 309L in the primary water environment was minimal. The galvanic corrosion rate of the SA-508 LAS and Type 309L SS couple measured under the simulated power operation condition was much lower than that measured in the simulated shutdown condition due to the formation of magnetite on the metal surface in a reducing environment. Based on the experimental results, the corrosion rate of SA-508 LAS clad with Type 309L SS was estimated as a function of operating cycle simulated for a typical PWR.

The Effect of a Proximal and Distal Tibiofibular Joint Manipulation on Dorsiflexion and Balance in Individuals with a History of Lateral Ankle Sprain

  • Chae, Yun-Won;Park, Ji-Won;Nam, Ki-Seok
    • The Journal of Korean Physical Therapy
    • /
    • v.29 no.2
    • /
    • pp.95-100
    • /
    • 2017
  • Purpose: This study aimed to evaluate the changes in dorsiflexion and balance following proximal and distal tibiofibular joint manipulation in individuals with a history of lateral ankle sprain (LAS). Methods: Fifteen participants with a history of unilateral LAS, exhibiting a restriction in ankle dorsiflexion were included in this study. LAS ankle received a manipulation to the proximal and distal tibiofibular joint, while the opposite control ankle received no manipulation intervention. The outcome measures included ankle dorsiflexion and balance. Ankle dorsiflexion was measured using weight-bearing lunge test. Static and dynamic balances were measured using the overall, anterioposterior, and mediolateral balance index via the biodex balance system. Measurements were obtained prior to and following manipulation. Results: This study showed that ankle dorsiflexion and dynamic balance were improved following the manipulation compared to those prior to the manipulation (p<0.05). There was no significant change in static balance (p>0.05). Conclusion: The joint manipulation technique applied to the ankle of those with a history of LAS appears to improve ankle dorsiflexion and dynamic balance. This suggest that a manipulation to the proximal and distal tibiofibular joint could be provided as preliminary data regarding the prophylactic effects of recurrent LAS.

Un Estudio sobre la Organización Nacional de República Argentina Moderna : Enfocando en el Conflicto entre los Federales y los Unitarios (독립 후 아르헨티나공화국의 수립과정 연구 : 연방파와 통합파의 갈등을 중심으로)

  • Cho, Young-Shil
    • Iberoamérica
    • /
    • v.13 no.1
    • /
    • pp.287-317
    • /
    • 2011
  • En este trabajo tratamos de investigar el proceso la constitución nacional de la República Argentina moderna, enfocando en la contradicción entre los federales y los unitarios. En el capítulo II, ante todo hemos definido el origen y el contexto de formación de cada ideología y partido. El centro de los federales estaba en las provincias interiores y litorales, mientras que los unitarios hacen de centro la provincia de Buenos Aires. En el capítulo III, mostramos las causas de esta contradicción histórica y tratamos de caracterizar las diferencias. Explícitamente el conflicto se basa en la distinción de la visión política e ideológica, es decir, la distinción de cómo orientar la constitución nacional de la república incipiente. Sin embargo, es inevitable referir la división administrativa histórica durante la época colonial. Al mismo tiempo no debemos faltar el conflicto de interés económico respecto al puerto de Buenos Aires. En el capítulo IV, analizamos comparando las ideas de dos intelectuales, las cuales hacen un papel importante en la organización nacional. Primero analizamos el pensamiento civilizatorio de Sarmiento, y después, demostramos el pensamiento federalista de Alberdi como origen de la constitución argentina de 1853, y de la inmigración europea. Como consecuencia del estudio, podemos llegar a la conclusión de que los esfuerzos por realizar la organización nacional no siempre estaban en línea paralela de ambos partidos divididos, sino tenemos un ejemplo dialéctico y combinatorio como el caso de Alberdi.

Models for Formation of Chloroform by Reaction of Linear Alkylbenzenesulfonate with Free Chlorine (LAS의 염소와 반응에 의한 클로로포름 생성 모델)

  • 김혜태;남상호
    • Environmental Analysis Health and Toxicology
    • /
    • v.13 no.3_4
    • /
    • pp.77-85
    • /
    • 1998
  • It is very frequent that LAS meets the chlorine bleaches not only in the processes but also in the path from the sewages to the rivers. Therefore, it is not difficult to imagine that the harmful substances like DBPs are produced when LAs reacts with free chlorine. THMs are the major components of DBPs which are formed by reactions of organic substances with the chlorine oxidants. Among them, chloroform is the most noteworthy material. Since the major behavior observed was the formation of chloroform during reaction of LAS with free chlorine, the models were developed to grasp the tendency of chloroform formation depending on condition. According to these models, the effect of pH in the formation of chloroform is most grave.

  • PDF