• Title/Summary/Keyword: T-history method

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New techniques for estimating the shut-in pressure in hydro-fracturing pressure-time curves

  • Choi Sung O.
    • 한국지구물리탐사학회:학술대회논문집
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    • 2003.11a
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    • pp.272-280
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    • 2003
  • A definite shut-in pressure in hydraulic fracturing techniques is needed for obtaining the correct information on the in-situ stress regimes in rock masses. The relation between the behaviour of hydraulically induced fractures and the condition of remote stress is considered to be major reasons of an ambiguous shut-in pressure in hydraulic fracturing pressure-time history curves. This paper describes the results of a series of numerical analyses carried out using UDEC(Universal Distinct Element Code, Itasca), which is based on the discrete element method, to compare several methods for determining the shut-in pressure during hydraulic fracturing. The fully coupling of hydraulic and mechanical analysis was applied, and the effects of four different discontinuity geometries in numerical modelling have been investigated for this purpose. The effects of different remote stress regimes and different physical properties on hydraulic fracture propagation have been also analyzed. Several methods for obtaining shut-in pressure from the ambiguous shut-in curves have been applied to all the numerical models. The graphical intersection methods, such as (P vs. t) method, (P vs. log(t)) method, (log(P) vs. log(t)) method, give smaller values of the shut-in pressure than the statistical method, (dP/dt vs. P). Care should be taken in selecting a method for shut-in pressure, because there can be existed a stress anomaly around the wellbore and fracturing from the wellbore by a constant flow rate may have a more complicate mechanism.

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A Comparative Study on Euclid's Elements and Pardies' Elements (Euclid 원론과 Pardies 원론의 비교 연구)

  • Chang, Hyewon
    • Journal for History of Mathematics
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    • v.33 no.1
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    • pp.33-53
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    • 2020
  • Euclid's Elements has been considered as the stereotype of logical and deductive approach to mathematics in the history of mathematics. Nonetheless, it has been criticized by its dryness and difficulties for learning. It is worthwhile to noticing mathematicians' struggle for providing some alternatives to Euclid's Elements. One of these alternatives was written by a French scientist, Pardies who called it 'Elemens de Geometrie ou par une methode courte & aisee l'on peut apprendre ce qu'il faut scavoir d'Euclide, d'Archimede, d'Apllonius & les plus belles inventions des anciens & des nouveaux Geometres.' A precedent research presented its historical meaning in traditional mathematics of China and Joseon as well as its didactical meaning in mathematics education with the overview of this book. However, it has a limitation that there isn't elaborate comparison between Euclid's and Pardies'in the aspects of contents as well as the approaching method. This evokes the curiosity enough to encourage this research. So, this research aims to compare Pardies' Elements and Euclid's Elements. Which propositions Pardies selected from Euclid's Elements? How were they restructured in Pardies' Elements? Responding these questions, the researcher confirmed his easy method of learning geometry intended by Pardies.

The Current State of Wife Abuse and Related Variables in Seosan City, Chungnam Province (아내폭력의 실태와 관련변인들 - 충남 서산 지역의 사례를 중심으로 -)

  • Lee, Jong-Won;Ok, Sun-Wha;Nam, Young-Joo
    • Journal of the Korean Home Economics Association
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    • v.43 no.8 s.210
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    • pp.141-159
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    • 2005
  • The aim of this study was to investigate the current state of wife abuse in Seosan and the relationships between wife abuse and the related variables. A total of 132 couples took part in this study. All couples live in Seosan city, range in age from their 20s to 50s and each couple has at least one child. Stratification sampling method was used to select the couples. They were asked to complete self-report questionnaires. Subjects completed a Korean version of the self- esteem scale, marital conflict scale, communication style scale, family history of violence scale, alcohol dringking, and wife abuse scale. In order to examine the current state of wife abuse, such as, frequency, mean, standard deviation and paired t-test, t-test were calculated and analyzed. Next, to identify differences in wife abuse between the upper group and the lower group, t-test was peformed. Finally, to investigate the relative influences of independent variables upon wife-abuse, multiple regression analysis was peformed. All these analyses were conducted using SPSS 10.0 program. The results were as follows; 1) In terms of the current state of wife abuse, there are three main observations. First, $23\%$ of respondents answered that they had beat their spouse or been beaten by their spouse before and after their marriage. Second, compared with physical violence($2{\~}16\%$), other types of violence such as verbal($7{\~}4\%$), emotional($41{\~}64\%$), economical($3{\~}29\%$) and sexual violence($4{\~}38\%$) were reported to occur more often in these relationships. Third, following the abuse most wives tend to tolerate the situation instead of taking an active action like reporting the abuse to police. 2) As for the husbands, subjects that drank a high level of alcohol, blaming and super-reasonable communication style, and family history of violence reported more frequent cases of wife abuse. As for the wives, subjects with high levels of self-esteem, irrelevant communication style, marital conflict, and family history of violence reported having more cases of that abuse. 3) In the case of husbands, alcohol, communication style and family history of violence explained $40\%$ of wife abuse. In the case of wives, marital conflict and family history of violence explained $77\%$ of their experiences with abuse. This study makes the contribution to aims to develop education programs and family therapy relevant to prevent wife abuse and to reconsider the existing laws governing domestic violence in Korea.

Correlation between History of Exposure to Obscene Material, Sexual Attitudes and Intercourse Experience among University Students (대학생의 음란물 노출력과 성태도 및 성경험간의 상관성 분석)

  • Kim, Eun Man;Yu, Su Jeong;Song, Mi Ryeong
    • Journal of Korean Academy of Fundamentals of Nursing
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    • v.20 no.1
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    • pp.18-26
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    • 2013
  • Purpose: The purpose of this study was to analyze the history of exposure to obscene material, and examine sexual attitudes and intercourse experience in order to develop an effective program for university students. Method: The data were collected in May, 2012 from 385 students attending 3 universities in Korea. An independent t-test and ANOVA were used to determine the differences with regard to sexual attitudes and intercourse experience according to general characteristics and history of exposure to obscene material. Results: Sexual attitudes significantly differed according to timing of first exposure to obscene material (p<.001). Intercourse experience was significantly different according to timing of first exposure to obscene material (p=.016) and type of exposure to obscene material (p=.032). There was a negative correlation between first exposure to obscene material and sexual attitudes (p<.001), and a positive correlation between first exposure to obscene material and intercourse experience (p=.017). Conclusion: Results of this study indicate that history of exposure to obscene material should be considered as an important variable in managing the sexual health of university students.

Association between Sodium Excretion and Obesity of Adults in Gwangju (광주지역 성인의 나트륨 배설량과 비만의 관계)

  • Jo, Mijin;Heo, Young-Ran
    • Korean Journal of Community Nutrition
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    • v.23 no.1
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    • pp.38-47
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    • 2018
  • Purpose: The aim of this study was to analyze the association between sodium excretion and obesity for healthy adults in the Gwangju area. Methods: The participants included 80 healthy adults aged 19 to 69 years in Gwangju. The dietary intake and sodium excretion were obtained using the 24-hour recall method and 24 hour urine collection. The participants were classified into two groups according to the amount of urinary sodium excretion: (${\leq}141.75mmol/dL$, > 141.75 mmol/dL). Results: After adjusting for sex, age, smoking history, and income, the high excretion of sodium group was significantly higher for weight, body mass index, body fat mass, percent body fat, visceral fat area (VFA), waist circumference, hip circumference, and WHR. The energy and nutrients intake were significant after adjusting for sex, age, smoking history, and income. The LSE group had a significantly higher fat intake and Na/K intake ratio. The HSE group had significantly higher fiber intake, and K intake. As the amount of urinary sodium excretion increased, the risk of obesity before correction was 3.57 (95% CI: 1.13-11.25) times greater, and the risk of obesity of T3 increased significantly by 3.33 times (95% CI: 1.05-10.59). After correcting for sex and age, the obesity risk of T2 increased significantly by 4.23 times (95% CI: 1.11-16.06), and after correcting for sex, age, smoking history, and income, the obesity risk of T2 increased significantly by 6.81 times (95% CI: 1.44-32.19) the risk of obesity. Conclusions: An association exists between sodium excretion and obesity in Korean adults. In this study, the high excretion of sodium group was obese and the risk of obesity was higher than the low excretion of sodium group.

Comparative Study of Non-Smoke Group and Smoke Group by Diagnosis System of Oriental Medicine (흡연군과 비흡연군의 폐활량과 한방변증 비교분석)

  • Park, Sung-Jun;Kim, Jin-Young;Shin, Woo-Jin;Park, Dong-Il
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.23 no.2
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    • pp.505-511
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    • 2009
  • The purpose of this study is to evaluate the difference about pathogenesis of smoker and non-smoker. Author used DSOM to investigate oriental pathogenesis. Smoke group is consisted of people who have history of smoke, and they don't have history of lung disease(Athma, tuberculosis, COPD, suchlike). Non-smoke group is consisted of people who have no history of smoke and they also don't have history of lung disease. Author carried out each group's PFT(Pulmonary Function Test) by AST(American Thoracic Society) method. DSOM was used for pathogenesis investigation of two groups. There was significant difference between smoke group and non-smoke group in FVC (p<0.05), and In non-smoke group, there was significant difference between male and famale in FVC, FVC%, FEV1, FEV1%. There was significant difference between smoke group and non-smoke group in Heat(熱), Cold(寒)(p<0.05). In Male grouop there was significant difference between smoker and non-smoker in deficiency of Deficiency of Yin(陰虛), Heat(熱). In non-smoke group comparison of sex, there was significant difference between male and female in Deficiency of blood(血虛), dampness(濕)(p<0.05). This result showed that the difference of pathogenesis between smoke group and non-smoke group.

The MMP-2 -735 C Allele is a Risk Factor for Susceptibility to Breast Cancer

  • Yari, Kheirollah;Rahimi, Ziba;Moradi, Mohamad Taher;Rahimi, Zohreh
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.15
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    • pp.6199-6203
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    • 2014
  • Background: The expression of MMP genes has been demonstrated to be associated with tumor invasion, metastasis and survival rate for a variety of cancers. The functional promoter polymorphism MMP-2 C-735T is associated with decreased expression of the MMP-2 gene. The aim of present study was to detect any association between MMP-2 C-735T and susceptibility to breast cancer. Materials and Methods: The MMP-2 C-735T polymorphism was studied in 233 women (98 with breast cancer and 135 healthy controls). All studied women were from Kermanshah and Ilam provinces of Western Iran. The MMP-2 C-735T polymorphism was detected using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Results: The frequencies of MMP-2 CC, CT and TT genotypes in healthy individuals were 59.3, 38.5 and 2.2%, respectively. However, in breast cancer patients, only CC (71.4%) and CT (28.6%) genotypes were observed (p=0.077). In patients the frequency of the MMP-2 C allele was significantly higher (85.7%) compared to that in controls (78.5 %, p=0.048). The presence of C allele of MMP-2 increased the risk of breast cancer by 1.64-fold [OR=1.64 (95%CI 1.01-2.7, p=0.049)]. The frequency of MMP-2 C allele was also higher in patients ${\leq}40$ years (88.9%) than those aged ${\geq}41$ years (67.5%, p=0.07). In addition, the frequency of MMP-2 C allele tended to be higher in patients with a family history of cancer in first-degree relatives (76.6%) compared to that without a family history of cancer (67.3%, p=0.31). Conclusions: Our findings indicate that the C allele of MMP-2 C-735T polymorphism is associated with increased risk of breast cancer. Also, the MMP-2 C allele might increase the risk of young onset breast cancer in our population.

Field Application of Surface Insulation Curing Method to Cold Weather Concreting (한중콘크리트의 현장 표면단열 양생공법 시공사례 연구)

  • Kim Jong-Back;Lim Choon-Goun;Han Min-Cheol;Kim Seoung-Soo;Han Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2005.11a
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    • pp.25-28
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    • 2005
  • This study investigates the field application of surface insulation curing method, which combined double layer bubble sheet(DBS) and thick-curing-material(TCM) for cold weather concreting. According to the test, deck slab, curing only upper section with DBS and TCM, does not make big different temperature history with that, curing both upper and bottom section during daily average temperature 6.5t. It is concluded that combination of DBS and TCM in only upper section can be safely cured in early period of time during cold water concreting. The field test was carried out with this favourable data. The upper deck slab was insulated by combination of DBS and TCM, and the construction was surrounded by tent. in order to protect from outside wind. The test result shows that the lowest temperature of deck slab indicated 6$ ^{circ}C $. It demonstrated that this curing method can resist early frost and save construction cost in the side of management and saving labor cost, compared with previous method. In addition, the column specimen, combined both form and bubble board, exhibited favorable temperature history, due to internal hydration heat insulation effect.

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Soil structure interaction effects on structural parameters for stiffness degrading systems built on soft soil sites

  • Aydemir, Muberra Eser
    • Structural Engineering and Mechanics
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    • v.45 no.5
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    • pp.655-676
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    • 2013
  • In this study, strength reduction factors and inelastic displacement ratios are investigated for SDOF systems with period range of 0.1-3.0 s considering soil structure interaction for earthquake motions recorded on soft soil. The effect of stiffness degradation on strength reduction factors and inelastic displacement ratios is investigated. The modified-Clough model is used to represent structures that exhibit significant stiffness degradation when subjected to reverse cyclic loading and the elastoplastic model is used to represent non-degrading structures. The effect of negative strain - hardening on the inelastic displacement and strength of structures is also investigated. Soil structure interacting systems are modeled and analyzed with effective period, effective damping and effective ductility values differing from fixed-base case. For inelastic time history analyses, Newmark method for step by step time integration was adapted in an in-house computer program. New equations are proposed for strength reduction factor and inelastic displacement ratio of interacting system as a function of structural period($\tilde{T}$, T) ductility (${\mu}$) and period lengthening ratio ($\tilde{T}$/T).

Application of Response Spectrum Method for Analysis of a Floor System Subjected to Dynamic Loads on Multiple Locations (복수 절점에 가진되는 건물 바닥판의 해석을 위한 응답스펙트럼 해석법의 응용)

  • 김태호;이동근
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.15 no.1
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    • pp.21-32
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    • 2002
  • In general, the response spectrum analysis method (R.S.A) is widely used for seismic analysis of building structure. But, it is not common to apply R.S.A for the analysis of structural vibration caused by dynamic loads of equipments, machines and moving leads, etc. The time history analysis method(T.H.A) for the vibration analysis, compared with R.S.A, is very complex, difficult and time consuming. So the application of R.S.A, that is convenient to calculate maximum responses for structural vibration, is proposed in this study. At first, the procedure for the application of the R.S.A to calculate of the maximum vibration response induced by dynamic load applied on the single point is described. And then, the process, which can save the time and the memory for calculation of the maximum vibration response induced by dynamic loads on the multi-point is proposed, and the maximum structural response caused by moving loads are obtained. Lastly, the accuracy of the proposed method is verified by comparing the results of R.S.A to T.H.A for some example models.