• Title/Summary/Keyword: resistance level

Search Result 2,251, Processing Time 0.037 seconds

A simplified approach for fire-resistance design of steel-concrete composite beams

  • Li, Guo-Qiang;Wang, Wei-Yong
    • Steel and Composite Structures
    • /
    • v.14 no.3
    • /
    • pp.295-312
    • /
    • 2013
  • In this paper, a simplified approach based on critical temperature for fire resistance design of steel-concrete composite beams is proposed. The method for determining the critical temperature and fire protection of the composite beams is developed on the basis of load-bearing limit state method employed in current Chinese Technical Code for Fire safety of Steel Structure in Buildings. Parameters affecting the critical temperature of the composite beams are analysed. The results show that at a definite load level, section shape of steel beams, material properties, effective width of concrete slab and concrete property model have little influence on the critical temperature of composite beams. However, the fire duration and depth of concrete slab have significant influence on the critical temperature. The critical temperatures for commonly used composite beams, at various depth of concrete and fire duration, are given to provide a reference for engineers. The validity of the practical approach for predicting the critical temperature of the composite beams is conducted by comparing the prediction of a composite beam with the results from some fire design codes and full scale fire resistance tests on the composite beam.

Comprehensive Wear Study on Powder Metallurgical Steels for the Plastics Industry, Especially Injection Moulding Machines

  • Gornik, Christian;Perko, Jochen
    • Proceedings of the Korean Powder Metallurgy Institute Conference
    • /
    • 2006.09a
    • /
    • pp.399-400
    • /
    • 2006
  • M390 microclean(R) of $B{\ddot{o}}hler$ Edelstahl is a powder metallurgical plastic mould steel with a high level of corrosion and wear resistance and therefore often used in the plastics processing industry. But as a consequence of rapidly advancing developments in the plastics processing industry the required level of wear resistance of tool steels in this field is constantly rising. For that reason a new PM tool steel with higher hardness values and an increased amount of primary carbides has been developed to improve the resistance against abrasive and adhesive wear. The wear resistance of both steels against adhesive situations for components of the plastification unit of injection moulding machines has been tested with a novel method. In case of processing polyolefins with an injection moulding machine it was found that there is adhesive wear between the check-ring and the flights of the screw tip of the non-return valve under certain circumstances. The temperature in that region was measured with an infrared temperature sensor. The existence of significant peaks of that signal was used as an indicator for an adhesive wear situation.

  • PDF

Performance Assessment on Temperature Calibration Capability of the Calibration Laboratories Using High-Precision Platinum Resistance Thermometers (고정밀 백금저항온도계를 이용한 교정기관의 온도교정능력 수행평가)

  • Gam, Kee Sool;Lee, Young Hee;Yang, Inseok
    • Journal of Sensor Science and Technology
    • /
    • v.22 no.6
    • /
    • pp.415-420
    • /
    • 2013
  • Calibration capabilities for thermometer calibration by comparison method were assessed using high-precision industrial platinum resistance thermometers (IPRT). It was found in the performance assessment that out of 31 laboratories who participated, 28 laboratories resulted magnitude of En number less than 1 at every calibration points they submitted results in the range from 50 to $500^{\circ}C$. The results of about 75% of the laboratories showed the difference from the assigned values less than 1/10 of the tolerance level of the class B IPRT. This indicates that the participating calibration laboratories performed with satisfactory level that was enough to calibrate IPRTs to significant precision. The sensors used in this work were manufactured and chosen by the criteria of long-term instability less than 4 mK and hysteresis less than 8 mK in the temperature range used in this work. Furthermore, the change in the resistance of the sensors in the calibration temperature range were less than the uncertainty of the calibration, 25 mK (k=2).

Effects of Plank Exercises with Resistance of One-Sided Hip Adduction on the Abdominal Muscle Thickness

  • Park, JaeCheol;Jeong, JinGyu
    • The Journal of Korean Physical Therapy
    • /
    • v.31 no.2
    • /
    • pp.82-87
    • /
    • 2019
  • Purpose: The purpose of this study was to examine the effects of plank exercises with resistance of one-sided hip adduction on abdominal muscle thickness. Methods: Thirty subjects were divided into a group that underwent plank exercises with one-sided hip adduction resistance (n=15) and a group that underwent plank exercises only (n=15). Their changes in abdominal muscle thickness before the experiment (n=15) and three and six weeks after the experiment were analyzed using a two-way repeated analysis of variance at a statistical significance level of ${\alpha}=0.05$. When there was any interaction between the time of measurement and each group, post hoc t-tests were conducted at a statistical significance level of ${\alpha}=0.01$. Results: The results of the experiment showed statistically significant differences in the thickness of the rectus abdominis, internal oblique muscle, and transversus abdominis, depending on the time of measurement and the interaction between the time of measurement and each group (p<0.05). Statistically significant differences were observed in the thickness of the external oblique, depending on the time of measurement, the interaction between the time of measurement and each group, and variances between the groups (p<0.05). Conclusion: The results of this study indicated that plank exercises with resistance of one-sided adduction are effective for increasing abdominal muscle thickness. The study's overall findings will likely be used as basic data for lumbar stabilization exercises and rehabilitation treatment.

The Effects of Low Intensity Resisted and Aerobic Exercise Training on Blood Lipid in Chronic Stroke Patients (저강도의 저항운동과 유산소 운동 훈련이 만성 뇌졸중 환자의 혈중지질에 미치는 효과)

  • Lee, Dong-Yeop;Cho, Nam-Jeong
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.12 no.2
    • /
    • pp.753-758
    • /
    • 2011
  • The purpose of this study was to investigate effect of low intensity resistance exercise and aerobic exercise on serum lipid level in chronic stroke patients. A total of 37 chronic stroke patients were enrolled in this study. The participants were allocated randomly to 2 groups: the low intensity resistance exercise group(n=19) and aerobic exercise group(n=18). Low intensity resistance exercise group took exercise with low intensity resistance for 50minutes, 5 times per week over a 8 week period. Aerobic exercise group received only aerobic exercise. We measured serum lipid level to compare of effectiveness both exercises. Paired t test was executed to determine differences between pre and post exercise. For all analyses, a significant level set at p<.05. The low intensity resistance exercise group showed significant increase in TG, TC HDL-C and LDL-C(p<.05). The aerobic exercise group had significantly higher TC and LDL-C (p<.05). Theses results suggest that low intensity resistance exercise and aerobic exercise are feasible for stroke patients by improving motivation and interest. Further studies is necessary to clinical implication classified by onset time and disability level.

Studies on Varietal Resistance to Sheath Blight Disease in Rice II. Varietal Difference of Resistance (벼 품종의 잎집무늬마름병 저항성 연구 II. 품종간 저항성의 차이)

  • Kim, Kwang-Ho;Yang, Kae-Jin;Lee, Sang-Bok
    • KOREAN JOURNAL OF CROP SCIENCE
    • /
    • v.32 no.3
    • /
    • pp.302-309
    • /
    • 1987
  • One hundred rice varieties were tested for their level of resistance to sheath blight disease at adult plant stage in field condition through 1984 to 1986. Rice plants were grown under ordinary seasonal culture and inoculated by k-2 fungus isolate during three years. k -1 isolate was also inoculated separately in 1984 and test under late seasonal culture was conducted in separate field in 1985. Degree of damage by the disease observed at 25 days after heading was used to identify the level of resistance of the rice varieties tested. Varietal differences of degree of damage were significant in five tests during three years, and the genotypic variance of degree of damage was always higher than environmental variance among varieties tested. Positive correlations between testing years, between cultural seasons, and between isolates inoculated were found in degree of damage of varieties tested for two or three years continuously. Degree of damage by the disease was correlated negatively with heading date of rice varieties except 1984 tests. Thus, the level of resistance should be compared among the variety group having almost same heading date in field condition, and late and extremely late variety groups should be tested for their level of resistance under appropriate environmental condition. Gayabyo, an early heading variety, and SR9713-54-3, a medium heading breeding line, showed consistent lower value of degree of damage during two or three years. These two varieties were selected as moderate resistant germplasm.

  • PDF

Role of Integrin-Linked Kinase in Multi-drug Resistance of Human Gastric Carcinoma SGC7901/DDP Cells

  • Song, Wei;Jiang, Rui;Zhao, Chun-Ming
    • Asian Pacific Journal of Cancer Prevention
    • /
    • v.13 no.11
    • /
    • pp.5619-5625
    • /
    • 2012
  • Gastric carcinoma is a leading cause of cancer death in the world and multi-drug resistance (MDR) is an essential aspect of gastric carcinoma chemotherapy failure. Recent studies have shown that integrin-linked kinase (ILK) is involved in metastasis of human tumors, expression silencing of ILK inhibiting the metastasis of several types of cultured human cancer cells. However, the role and potential mechanism of ILK to reverse the multi-drug resistance in human gastric carcinoma is not fully clear. In this report, we focused on roles of expression silencing of ILK in multi-drug resistance reversal of human gastric carcinoma SGC7901/DDP cells, including increased drug sensitivity to cisplatin, cell apoptosis rates, and intracellular accumulation of Rhodamine-123, and decreased mRNA and protein expression of multi-drug resistance gene (MDR1), multi-drug resistance-associated protein (MRP1), excision repair cross-complementing gene 1 (ERCC1), glutathione S-transferase -${\pi}$ (GST-${\pi}$) and RhoE, and transcriptional activation of AP-1 and NF-${\kappa}B$ in ILK silenced SGC7901/DDP cells. We also found that there was a decreased level of p-Akt and p-ERK. The results indicated that ILK might be used as a potential therapeutic strategy to combat multi-drug resistance through blocking PI3K-Akt and MAPK-ERK pathways in human gastric carcinoma.

Numerical Assessment of Reinforcing Details in Beam-Column Joints on Blast Resistance

  • Lim, Kwang-Mo;Shin, Hyun-Oh;Kim, Dong-Joo;Yoon, Young-Soo;Lee, Joo-Ha
    • International Journal of Concrete Structures and Materials
    • /
    • v.10 no.sup3
    • /
    • pp.87-96
    • /
    • 2016
  • This numerical study investigated the effects of different reinforcing details in beam-column joints on the blast resistance of the joints. Due to increasing manmade and/or natural high rate accidents such as impacts and blasts, the resistance of critical civil and military infrastructure or buildings should be sufficiently obtained under those high rate catastrophic loads. The beam-column joint in buildings is one of critical parts influencing on the resistance of those buildings under extreme events such as earthquakes, impacts and blasts. Thus, the details of reinforcements in the joints should be well designed for enhancing the resistance of the joints under the events. Parameters numerically investigated in this study include diagonal, flexural, and shear reinforcing steel bars. The failure mechanism of the joints could be controlled by the level of tensile stress of reinforcing steel bars. Among various reinforcing details in the joints, diagonal reinforcement in the joints was found to be most effective for enhancing the resistance under blast loads. In addition, shear reinforcements also produced favourable effects on the blast resistance of beam-column joints.

Invisible Signals from the Underground: Bacterial Volatiles Elicit Plant Growth Promotion and Induce Systemic Resistance

  • Ryu, Choong-Min;Farag, Mohammed A.;Pare, Paul. W.;Kloepper, Joseph W.
    • The Plant Pathology Journal
    • /
    • v.21 no.1
    • /
    • pp.7-12
    • /
    • 2005
  • Plant growth-promoting rhizobacteria (PGPR) are a wide range of root-colonizing bacteria with the capacity to enhance plant growth and control plant pathogens. Here we review recent progress that indicate some PGPR strains release a blend of volatile organic compounds (VOCs) that promote growth in Arabidopsis seedlings and induce resistance against Erwinia carotovora subsp. carotovora. In particular, the volatile components 2,3-butanediol and acetoin released exclusively from the PGPR strains triggered the greatest level of growth promotion and induced systemic resistance. Pharmacological applications of 2,3-butanediol promoted the plant growth and induced resistance, while bacterial mutants blocked in 2,3-butanediol and acetoin synthesis was devoid of growth-promotion and induced resistance capacities. The results suggested that the bacterial VOCs play a critical role in the plant growth promotion and induced resistance by PGPR. Using transgenic and mutant lines of Arabidopsis, we provide evidences that the signal pathway activated by volatiles from one PGPR strain is dependent on cyto-kinin activation for growth promotion and dependent on an ethylene-signaling pathway for induced pathogen resistance. This discovery provides new insight into the role of bacterial VOCs as initiators of both plant growth promotion and defense responses in plants.

Characterization of Plasmids from Multiple Antibiotic Resistant Vibrio sp. Isolated from Molluscs and Crustaceans

  • Manjusha, Sayd;Sarita, Ganabhat Bhat
    • Microbiology and Biotechnology Letters
    • /
    • v.40 no.3
    • /
    • pp.197-207
    • /
    • 2012
  • This study investigated the role of plasmids and their relationship with the multiple antibiotic resistance of 30 Vibrios sp. isolated from molluscs and crustaceans sampled from the Kerala coastal waters of India. The biochemical identification and antibiotic resistance profiles were determined, followed by the plasmid profiles, conjugation and transformation efficiencies. The results showed a considerable difference in the level of bacterial resistance to various antibiotics; while all 30 strains were found to be MAR Vibrios sp. and their resistance patterns varied. All the strains were resistant to amoxycillin, ampicillin and carbeniciliin. 87% were resistant to rifampicin; 74% to cefuroxime; 67 to streptomycin; 53% to norfloxacin and ciprofloxacin and 47% to furazolidone and nalidixic acid. In addition to their antibiotic resistance, the plasmid DNA of the MAR Vibrios strains isolated from the molluscs and crustaceans was also studied. Nine strains isolated from crustaceans and molluscs were found to harbor 1-3 plasmids with sizes varying from 5. 98 kb to 19. 36 kb. The average transformation efficiency was about $5{\times}10^{-8}$ and the conjugation efficiency varied from $2.1{\times}10^{-3}$ to $10^{-9}$. A further study of antibiotic resistance patterns may be useful to test the extent of drug resistance in seafoods and help to devise a nationwide antibiotic policy.