• 제목/요약/키워드: Adverse Influence

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Critical setback distance for a footing resting on slopes under seismic loading

  • Shukla, Rajesh Prasad;Jakka, Ravi S.
    • Geomechanics and Engineering
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    • 제15권6호
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    • pp.1193-1205
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    • 2018
  • A footing located on slopes possess relatively lower bearing capacity as compared to the footing located on the level ground. The bearing capacity further reduces under seismic loading. The adverse effect of slope inclination and seismic loading on bearing capacity can be minimized by proving sufficient setback distance. Though few earlier studies considered setback distance in their analysis, the range of considered setback distance was very narrow. No study has explored the critical setback distance. An attempt has been made in the present study to comprehensively investigate the effect of setback distance on footing under seismic loading conditions. The pseudo-static method has been incorporated to study the influence of seismic loading. The rate of decrease in seismic bearing capacity with slope inclination become more evident with the increase in embedment depth of footing and angle of shearing resistance of soil. The increase in bearing capacity with setback distance relative to level ground reduces with slope inclination, soil density, embedment depth of footing and seismic acceleration. The critical value of setback distance is found to increase with slope inclination, embedment depth of footing and density of soil. The critical setback distance in seismic case is found to be more than those observed in the static case. The failure mechanisms of footing under seismic loading is presented in detail. The statistical analysis was also performed to develop three equations to predict the critical setback distance, seismic bearing capacity factor ($N_{{\gamma}qs}$) and change in seismic bearing capacity (BCR) with slope geometry, footing depth and seismic loading.

Nutrient Amendments Influence Endophytic Colonization of Rice by Serratia marcescens IRBG500 and Herbaspirillum seropedicae Z67

  • Gyaneshwar, P.;Reddy, Pallavolu M.;Ladha, Jagdish K.
    • Journal of Microbiology and Biotechnology
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    • 제10권5호
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    • pp.694-699
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    • 2000
  • Serratia marcescens IRBG500 and Herbaspirillum seropedicae Z67 grow endophytically in rice. The ability of these bacteria to colonize rice grown under increased nutrient availability was assessed in variety IR72 using strains marked with transposon-based gusA. The endophytic colonization was monitored via bacterial enumeration and histochemical visualization of GUS expression of bacteria in plant tissues. Rhizoplane and endophytic colonization by both bacteria was significantly inhibited in the rice plants grown in the presence of 10 mM $NH_4Cl$. In contrast, the addition of 10 mM $KNO_3$ showed no adverse effect on colonization. Increasing the concentration of $Ca^{2+}$ to 5 mM significantly reduced endophytic colonization by both bacterial strains, whereas the addition of 0.5 mM $Fe^{2+}$ substantially lowered the colonization of roots by S. marcescens IRBG500 but showed no effect on colonization by H. seropedicae Z67. Taken together, these finding suggest that, like in legume-rhizobial symbiosis as well as plant-pathogen interactions, nutrient status, particularly $NH_4^+$ and $Ca^{2+}$ concentrations in the surrounding medium, plays an important role in the regulation of endophytic infection and colonization processes in rice.

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Evaluation of the effect of aggregate on concrete permeability using grey correlation analysis and ANN

  • Kong, Lijuan;Chen, Xiaoyu;Du, Yuanbo
    • Computers and Concrete
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    • 제17권5호
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    • pp.613-628
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    • 2016
  • In this study, the influence of coarse aggregate size and type on chloride penetration of concrete was investigated, and the grey correlation analysis was applied to find the key influencing factor. Furthermore, the proposed 6-10-1 artificial neural network (ANN) model was constructed, and performed under the MATLAB program. Training, testing and validation of the model stages were performed using 81 experiment data sets. The results show that the aggregate type has less effect on the concrete permeability, compared with the size effect. For concrete with a lower w/b, the coarse aggregate with a larger particle size should be chose, however, for concrete with a higher w/c, the aggregate with a grading of 5-20 mm is preferred, too large or too small aggregates are adverse to concrete chloride diffusivity. A new idea for the optimum selection of aggregate to prepare concrete with a low penetration is provided. Moreover, the ANN model predicted values are compared with actual test results, and the average relative error of prediction is found to be 5.62%. ANN procedure provides guidelines to select appropriate coarse aggregate for required chloride penetration of concrete and will reduce number of trial and error, save cost and time.

Association of Length of Pregnancy with Other Reproductive Traits in Dairy Cattle

  • Nogalski, Zenon;Piwczynski, Dariusz
    • Asian-Australasian Journal of Animal Sciences
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    • 제25권1호
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    • pp.22-27
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    • 2012
  • The experiment involved observations of 2,514 Holstein-Friesian cows to determine the effects of environmental factors (cow's age, calving season, weight and sex of calves, housing system) and genetic factors on gestation length in dairy cattle and the correlation between gestation length and other reproductive traits (calving ease, stillbirth rates and placental expulsion). Genetic parameters were estimated based on the sires of calved cows (indirect effect) and the sires of live-born calves (direct effect). The following factors were found to contribute to prolonged gestation: increasing cow's age, male fetuses and growing fetus weight. Optimal gestation length was determined in the range of 275-277 days based on calving ease and stillbirth rates. The heritability of gestation length was estimated at 0.201-0.210 by the direct effect and 0.055-0.073 by the indirect effect. The resulting genetic correlations suggest that the efforts to optimize (prolong) gestation length could exert an adverse influence on the breeding value of bulls by increasing perinatal mortality and calving difficulty. The standard errors of the investigated parameters were relatively high, suggesting that any attempts to modify gestation length for the purpose of improving calving ease and reducing stillbirth rates should be introduced with great caution.

A Cross-Country Comparison of Knowledge, Attitudes and Practices about Tobacco Use: Findings from the Global Adult Tobacco Survey

  • Gupta, Bhawna;Kumar, Narinder
    • Asian Pacific Journal of Cancer Prevention
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    • 제15권12호
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    • pp.5035-5042
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    • 2014
  • Background: Knowledge and individual perceptions about adverse effects of all forms of tobacco exert direct influence on the level of tobacco consumption in various socio-demographic groups. The objective of this study was to determine the nature, extent and demographic correlates of knowledge, attitudes and perceptions of use of tobacco among adults in low and middle income countries. Materials and Methods: The Global Adult Tobacco Survey, conducted in fourteen different countries from 2008-2010, was sourced for the data analyzed in this study. Descriptive statistical analyses were conducted to determine the prevalent knowledge and individual perceptions amongst adults about all forms of tobacco consumption. Results: There was relatively high awareness about the harmful effects of smoking tobacco with main awareness being about its relationship with lung cancer (>90% in most countries). In contrast, there was relatively low awareness about harmful effects of smokeless tobacco (< 90% in all countries except India and Bangladesh), and observed correlation of smoking tobacco with heart attack (40.6% in China, 65.1% in India) and stroke (28.2% in China, 50.5% in India). Conclusions: A large proportion of adults living in low and middle income countries possess adequate knowledge about smoking tobacco but have inadequate awareness as well as false perceptions about smokeless forms of tobacco. Popular beliefs of inverse relationships of tobacco consumption with knowledge, attitudes and perception of populations towards tobacco are challenged by the findings of this study.

Bank-specific Factors Affecting Non-performing Loans in Developing Countries: Case Study of Indonesia

  • Rachman, Rathria Arrina;Kadarusman, Yohanes Berenika;Anggriono, Kevin;Setiadi, Robertus
    • The Journal of Asian Finance, Economics and Business
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    • 제5권2호
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    • pp.35-42
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    • 2018
  • In recent decades, financial crises in various countries have often been preceded by the rise in non-performing loans (NPLs) in the banks' asset portfolios. The increase in NPLs is proven to have adverse impact on the banking sector so that understanding the determinant of NPLs is immensely crucial to ensure the efficiency and soundness of the overall economy. This study aims to shed light on bank-specific factors that affect loan default problems in developing countries whose banking sectors play a major role in the overall economy. This study analyzes panel data sets of 36 commercial banks listed in the Indonesian Stock Exchange during the period 2008-2015. Applying fixed-effects panel regression model reveals that Indonesian banks' profitability and credit growth negatively influence the number of NPLs. Moreover, banks with higher profitability are proven to have lower NPLs because they can afford adequate credit management practices. Likewise, banks with higher credit growth evidently have lower NPLs in the sense that they demonstrate more specialized lending activity and thus have better credit management systems. These findings imply that, in order to lower loan defaults that can deteriorate banks' asset quality, banks should maintain their level of profitability and increase, rather than decrease, their credit supply to debtors.

티타늄 정밀주조품의 피로수명에 미치는 개재물의 영향에 관한 연구 (A Study on the Effect of Inclusions on the Fatigue Life of Titanium Investment Castings)

  • 박용국;;김진곤
    • 한국주조공학회지
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    • 제26권2호
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    • pp.85-91
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    • 2006
  • Inclusions in Ti investment castings are generally known to have detrimental effects on the performance of the castings. However, actual inclusions are infrequent and hard to be located. As a result, it is extremely difficult to obtain sufficient amount of fatigue test specimens of titanium investment castings having inclusions in the gage section. Thus, in-depth research of the adverse influence of inclusions is also hindered. To address this problem, a new casting methodology of specimens containing hard alpha inclusions was developed in this study. To guarantee successful introduction of an inclusion and casting, a carefully designed mold with 8 legs and a special tool were employed. After solidification, castings were cut, and X-ray radiography determined that the inclusions were successfully incorporated into the castings. The castings were further prepared to obtain multiple test specimens and they were fatigue-tested consecutively. Fractography analysis confirmed that fatigue cracks initiated at the hard alpha inclusion. In a nonlinear regression model, the fatigue life can be modeled as an exponential function with a negative exponent of the cross-sectional area of an inclusion. The fatigue life of Ti specimens containing inclusions is inversely proportional to the cross-sectional area of an inclusion.

Gamma spectrum denoising method based on improved wavelet threshold

  • Xie, Bo;Xiong, Zhangqiang;Wang, Zhijian;Zhang, Lijiao;Zhang, Dazhou;Li, Fusheng
    • Nuclear Engineering and Technology
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    • 제52권8호
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    • pp.1771-1776
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    • 2020
  • Adverse effects in the measured gamma spectrum caused by radioactive statistical fluctuations, gamma ray scattering, and electronic noise can be reduced by energy spectrum denoising. Wavelet threshold denoising can be used to perform multi-scale and multi-resolution analysis on noisy signals with small root mean square errors and high signal-to-noise ratios. However, in traditional wavelet threshold denoising methods, there are signal oscillations in hard threshold denoising and constant deviations in soft threshold denoising. An improved wavelet threshold calculation method and threshold processing function are proposed in this paper. The improved threshold calculation method takes into account the influence of the number of wavelet decomposition layers and reduces the deviation caused by the inaccuracy of the threshold. The improved threshold processing function can be continuously guided, which solves the discontinuity of the traditional hard threshold function, avoids the constant deviation caused by the traditional soft threshold method. The examples show that the proposed method can accurately denoise and preserves the characteristic signals well in the gamma energy spectrum.

논둑 태우기가 논 주변 환경에 미치는 영향 (Influence of Levee-burning on the Surroundings of Rice Paddies)

  • 이영인;김길호
    • 한국응용곤충학회지
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    • 제42권4호
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    • pp.345-352
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    • 2003
  • 논둑 불태우기의 당위성을 찾기 위하여 1995년부터 1997까지 2년동안 안동 지방 2개 지역 농가 포장에서 논둑을 태운 뒤의 잡초상, 곤충상 및 거미상과 아울러 다각적인 환경요인에 미치는 영향을 분석하였다. 분석 결과 및 기존자료들을 종합하여 볼 때 잡초상, 곤충상 및 도열병발생 등에는 별 영향이 없고 거미상 및 논둑 보존 등에는 불리하게 작용하며 더욱이 산불의 원인이 될 수 있는 등 뚜렷한 득은 없고 확실한 손실만을 초래하는 것으로 판단되어 논둑 불태우기를 절대 금하는 기초자료로 활용할 것을 건의한다.

크리프에 따른 CRT 텐션 마스크의 장력 이완 (Creep-Induced Tension Loosening of CRT Tension Mask)

  • 정일섭
    • 대한기계학회논문집A
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    • 제27권6호
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    • pp.1034-1040
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    • 2003
  • Tension mask is a part of CRT type devices, which is installed right behind glass-made front panel. Numerous slits on the thin metal sheet enable the electron beams emitted from posterior gun to be focused, resulting in enhanced definition. Flattened and enlarged displays necessitate the imposition of pretension on the masks, in order to improve the robustness of display quality against vibration or impact. High temperature assembly process subsequent to pretensioning, however, degenerates creep resistance of mask material, and common mask may become susceptible to undesirable elongation due to creep. Once tensile stress becomes high enough to induce creep deformation, pretension is substantially loosened. In this study, tension mask assembly is modeled as a combined structure of beams and wire array, and a numerical simulation is attempted for pretensioning followed by high temperature process. Based on a model study, creep occurrence is found to be probable and its adverse influence is quantified. As fur maintaining high tensile force, simply increasing pretension does not seem to be helpful. Instead, the structure of frame needs to be modified somehow, or material for mask needs to be selected properly.