• Title/Summary/Keyword: preS1

Search Result 3,711, Processing Time 0.034 seconds

The Effect of Guided Autobiography on Ego-Integrity, Depression and Life Satisfaction and the Heuristic Meaning in the Elderly (집단 자서전쓰기가 노년기 자아통합, 우울 및 생활만족도에 미치는 효과와 체험적 의의)

  • Lyu, Jung In;Cho, Haekyung;Kim, Byung Suk
    • 한국노년학
    • /
    • v.32 no.2
    • /
    • pp.559-576
    • /
    • 2012
  • This research aims to address the effect of Guided Autobiography(GAB) on ego-integrity, depression and life-satisfaction in the elderly and to investigate psychological changes and experiences on the senior subject. 20 subjects participated weekly autobiography writing sessions in a senior academy in the S city for 13 weeks. In this research, we carried out examination on ego-integrity, depression test, and life-satisfaction survey were performed before and after the writing sessions for a quantitative analysis, which was later investigated through a 'corresponding sample T-test'. Based on the results of the above mentioned tests, the qualitative analysis was conducted through an individual sessions with 5 selected participants. The results of this research are summarized as following. First, ego-integrity showed satisfactorily meaningful difference between pre- and post-GAB writing. The participants recollected the past repent and revisited unresolved issues in their lives. The subjects were able to accept these past misdemeanors and appreciate their lives. GAB indeed helped improving ego-integrity. Second, the hypothesis that GAB writing will help decrease depression was accepted. 2-page weekly writing assignments enabled the participants think of joyful moments in their past, and showed decrease the symptoms of depression. Third, this study revealed that GAB writing improved life- satisfaction. The participants learned to express gratitude and peace in their mind. The happy feeling and optimistic thoughts enhanced their satisfaction of life in turn. In addition, it turned out that the effects of GAB were more drastic in group sessions than in individual writings. Interpersonal interactions in group sessions encouraged the exchange of positive feedback, thereby helping them reflect themselves positively.

A Study on the Social Activities Perceived by the Korean elderly (노인이 인식하는 사회활동에 대한 연구)

  • Cheong, Byeong-Eun;Yi, Gihong
    • 한국노년학
    • /
    • v.29 no.3
    • /
    • pp.953-970
    • /
    • 2009
  • The successful aging paradigm suggests that the elderly keep their social ties and actively participate in various activities in later life. Many Korean studies on aging, however, have overlooked the importance of various social activities and relationships beyond kinship. This article aims to investigate the perceived social activities among Korean elders to comprehend the subjectivity of successful aging. 613 respondents, over 50 years old, are selected from a national survey data which was collected by face-to-face interview based on the structured questionnaire. The respondents are classified into pre old (50-64), young old (65-74), old old (over 75). Major findings are as follows. The social activities are grouped into two sub-categories: 'relational activity' and 'productive activity'. The activity types are different by the age cohorts. Various activities are considered in terms of one's needs or motivations, and properly chosen based on the subjective evaluation during life course. Both demographic variables such as sex, area and social context variables such as marital status, living-together show influence on the activity type choices. Plans for later life and work ethics are important as well. Policies regarding social participation emphasizing productivity should positively consider relational motives, as perceived by the Korean elderly.

The Hermeneutics of Religious Experience : Daesoon Thought in the light of Schillebeeckx's Theological Hermeneutics (종교체험의 해석적 성격: 스힐레벡스의 해석학으로 본 대순 사상)

  • Lee, Chan-Su
    • Journal of the Daesoon Academy of Sciences
    • /
    • v.17
    • /
    • pp.93-112
    • /
    • 2004
  • This article examines the process of how Daesoon thought keeps its own identity while being practiced as a religion in Korean culture through the perspective of theological hermeneutics of E. Schillebeeckx, a representative theologian in 20th century, especially on the centering of the matter of experience. Schillebeeckx says that an experience is an occurrence of perception by encountering something different from oneself. According to him, 1) the occurrence of perception is premised on a framework or form of interpretation which prescribes experience as the experience in the perceptive dimension. 2) A framework of interpretation is subject to pre-existing system or structure which already has formed a basis to the experience. It consists of various interpretative elements such as social form, general knowledges, various experiences, theoretical models in their society, etc.. 3) The experiences take place in the reflection of contemporary situation, and it is understood by a society, thus making it a social stream. This experience is expressed historically, gains historicity in the process of being handed down from person to person, from generation to generation. In this way, an experience starts to form a tradition. 4) The tradition is a historical stream which gives rise to, admits, and integrates various experiences, religious revelation, and faith etc. In this way, the tradition as a historical stream becomes a field of religious actuality such as revelation, salvation, etc. Conclusively, a religion takes place, is formed, only when it is understood anew by the people who live in that cultural tradition through their languages. The ground Daesoon thought takes place, is formed, is in this way. Daesoon thought takes place in the core of traditional Korean culture, undergoes changes when it encounters the other stream of traditional Korean culture, and the vice versa. Because of this inevitable change, ironically enough, Daesoon thought can maintain its own identity as Daesoon thought, and Korean culture its own identity as Korean culture, avoiding falling into the tertiary which is neither Daesoon thought nor Korean culture. It is in this way that any religion can be in the faithfulness to its starting point to be enriched and transformed in its interaction with the other tradition. At here is the reason Daesoon thought has to have an openness to the changing world.

  • PDF

A Marketing Theory-Based Approach to Customer's Perceived Shopping Experience (고객의 지각된 쇼핑경험에 대한 마케팅 이론적 접근)

  • Yoon, Sung-Joon;Choi, Dong-Choon
    • Asia Marketing Journal
    • /
    • v.10 no.1
    • /
    • pp.95-131
    • /
    • 2008
  • This study serves the main research purpose of verifying the hypothetical relationship between antecedent and consequence variables of shopping experience based on the classification system by Schmitt (1999) who dimensionalized experience into five components (sense, feel, think, act, relate). Specifically, the study seeks to fulfill the following three research objectives. First, it substantiates dynamic relationships among the five experiential components comprising the strategic experiential modules that serve as the basis of the theoretical framework of the study. Especially, it focuses on interactive relationships among the experiential components by taking a holistic view of the experience. Second, the study seeks to uncover the effects of pre-experiential antecedents such as shopping motivation and shopping involvement, based on taxonomy of motivation as product-centered vs. experience-centered. Third, the study investigates the effects of shopping experience on intention to revisit with regard to department store, discount store, and Internet shops, based on customers' store experiences. The major findings from this study are as follows: first, the five experiential components were found to have a high level of correlations according to hypothesis verification. Second, shopping motivation was learned to have significant effects on preference toward thinking as well as feeling experiences. That is, product-centered (vs. experience-centered) shopping motivation exerted a greater influence on cognitive (vs. affective experience than affective (vs. cognitive) experience.

  • PDF

A Survey on the Status of Health Examination among Farmers in a Rural Area (일부 농촌지역 농업종사자들의 건강진단 수검 실태)

  • Park, Soon-Woo
    • Journal of agricultural medicine and community health
    • /
    • v.22 no.1
    • /
    • pp.1-18
    • /
    • 1997
  • This study was carried out to reveal the status of health examination among farmers and to attract more attention to the health care system for farmers. Ten pre-trained medical students interviewed the rural residents 18 years of age and older in eight villages which were randomly selected from a county near Taegu city in Korea, in August 1996. Finally 751 persons were interviewed of whom the percentages of male and female were 41.8%, 58.2% respectively. Among the subjects, 361(48.3%) were fully engaged in farming, 184(24.4%) were partly engaged, and the remaining 206(27.3%) were not engaged in farming at all. The overall prevalence of farmer's disease was 23.0% and there was no significant difference between the group of fully engaged in farming(23.3%) and the group of not-fully engaged(22.9%). But the prevalence of farmer's disease in female subjects(27.8%) was significantly higher than that in male(16.2%)(p<0.01). Among the 288 farmer engaged in spraying pesticide, 113(39.2%) had experienced one or more pesticide related symptoms during last one year, but only 18(15.9%) of them had visited medical facilities due to their symptoms. The experience of receiving education about pesticide was significantly correlated with the degree of wearing protectors during pesticide spraying(p<0.001). Among the 736 persons excluding non-respondents, 281(38.2%) received health examination during last one year ; 176(62.6%) of them received free health examination, and 105(37.4%) received charged one. Among the 533 persons 40 years age and older, only 124(23.3%) had received the 'health examination for the elderly' during last one year, which is provided for the 40 years age and older by Korea medical insurance corporation and medical insurance societies. Most of all beneficiaries of self-employed medical insurance thought the imposed contributions as very expensive(77.4%) or moderately expensive(13.2%). The great majority of farmers are exposed to various health risk factors including pesticide, high temperature, overwork etc. comparable to industrial workers. But farmers are excluded from the regular yearly worker's health examination because of not belonging to a company despite they pay relatively more medical insurance contributions compared with the industrial workers and the urban self-employed medical insureds. It is necessary to develop special health management program for farmers such as the special health examination for the industrial workers exposed harmful agents.

  • PDF

Assessing the Damage: An Exploratory Examination of Electronic Word of Mouth (손해평고(损害评估): 대전자구비행소적탐색성고찰(对电子口碑行销的探索性考察))

  • Funches, Venessa Martin;Foxx, William;Park, Eun-Joo;Kim, Eun-Young
    • Journal of Global Scholars of Marketing Science
    • /
    • v.20 no.2
    • /
    • pp.188-198
    • /
    • 2010
  • This study attempts to examine the influence that negative WOM (NWOM) has in an online context. It specifically focuses on the impact of the service failure description and the perceived intention of the communication provider on consumer evaluations of firm competence, attitude toward the firm, positive word of mouth and behavioral intentions. Studies of communication persuasiveness focus on "who says what; to whom; in which channel; with what effect (Chiu 2007)." In this research study, we examine electronic web posting, particularly focusing on two aspects of "what": the level of service failure communicated and perceived intention of the individual posting. It stands to reason electronic NWOM that appears to be trying to damage a product’s or firm's reputation will be viewed as more biased and will thus be considered as less credible. According to attribution theory, people search for the causes of events especially those that are negative and unexpected (Weiner 2006). Hennig-Thurau and Walsh (2003) state "since the reader has only limited knowledge and trust of the author of an online articulation the quality of the contribution could be expected to serve as a potent moderator of the articulation-behavior relationship. We therefore posit the following hypotheses: H1. Subjects exposed to electronic NWOM describing a high level of service failure will provide lower scores on measures of (a) firm competence, (b) attitude toward the firm, (c) positive word of mouth, and (d) behavioral intention than will subjects exposed to electronic NWOM describing a low level of service failure. H2. Subjects exposed to electronic NWOM with a warning intent will provide lower scores on measures of (a) firm competence, (b) attitude toward the firm, (c) positive word of mouth, and (d) behavioral intention than will subjects exposed to electronic NWOM with a vengeful intent. H3. Level of service failure in electronic NWOM will interact with the perceived intention of the electronic NWOM, such that there will be a decrease in mean response on measures of (a) firm competence, (b) attitude toward the firm, (c) positive word of mouth, and (d) behavioral intention from electronic NWOM with a warning intent to a vengeful intent. The main study involved a2 (service failure severity) x2 (NWOM with warning versus vengeful intent) factorial experiment. Stimuli were presented to subjects online using a mock online web posting. The scenario described a service failure associated with non-acceptance of a gift card in a brick-and-mortar retail establishment. A national sample was recruited through an online research firm. A total of 113 subjects participated in the study. A total of 104 surveys were analyzed. The scenario was perceived to be realistic with 92.3% giving the scenario a greater than average response. Manipulations were satisfactory. Measures were pre-tested and validated. Items were analyzed and found reliable and valid. MANOVA results found the multivariate interaction was not significant, allowing our interpretation to proceed to the main effects. Significant main effects were found for post intent and service failure severity. The post intent main effect was attributable to attitude toward the firm, positive word of mouth and behavioral intention. The service failure severity main effect was attributable to all four dependent variables: firm competence, attitude toward the firm, positive word of mouth and behavioral intention. Specifically, firm competence for electronic NWOM describing high severity of service failure was lower than electronic NWOM describing low severity of service failure. Attitude toward the firm for electronic NWOM describing high severity of service failure was lower than electronic NWOM describing low severity of service failure. Positive word of mouth for electronic NWOM describing high severity of service failure was lower than electronic NWOM describing low severity of service failure. Behavioral intention for electronic NWOM describing high severity of service failure was lower for electronic NWOM describing low severity of service failure. Therefore, H1a, H1b, H1c and H1d were all supported. In addition, attitude toward the firm for electronic NWOM with a warning intent was lower than electronic NWOM with a vengeful intent. Positive word of mouth for electronic NWOM with a warning intent was lower than electronic NWOM with a vengeful intent. Behavioral intention for electronic NWOM with a warning intent was lower than electronic NWOM with a vengeful intent. Thus, H2b, H2c and H2d were supported. However, H2a was not supported though results were in the hypothesized direction. Otherwise, there was no significant multivariate service failure severity by post intent interaction, nor was there a significant univariate service failure severity by post intent interaction for any of the three hypothesized variables. Thus, H3 was not supported for any of the four hypothesized variables. This study has research and managerial implications. The findings of this study support prior research that service failure severity impacts consumer perceptions, attitude, positive word of mouth and behavioral intentions (Weun et al. 2004). Of further relevance, this response is evidenced in the online context, suggesting the need for firms to engage in serious focused service recovery efforts. With respect to perceived intention of electronic NWOM, the findings support prior research suggesting reader's attributions of the intentions of a source influence the strength of its impact on perceptions, attitude, positive word of mouth and behavioral intentions. The implication for managers suggests while consumers do find online communications to be credible and influential, not all communications are weighted the same. A benefit of electronic WOM, even when it may be potentially damaging, is it can be monitored for potential problems and additionally offers the possibility of redress.

A Study on Startups' Dependence on Business Incubation Centers (창업보육서비스에 따른 입주기업의 창업보육센터 의존도에 관한 연구)

  • Park, JaeSung;Lee, Chul;Kim, JaeJon
    • Korean small business review
    • /
    • v.31 no.2
    • /
    • pp.103-120
    • /
    • 2009
  • As business incubation centers (BICs) have been operating for more than 10 years in Korea, many early stage startups tend to use the services provided by the incubating centers. BICs in Korea have accumulated the knowledge and experience in the past ten years and their services have been considerably improved. The business incubating service has three facets : (1) business infrastructure service, (2) direct service, and (3) indirect service. The mission of BICs is to provide the early stage entrepreneurs with the incubating service in a limited period time to help them grow strong enough to survive the fierce competition after graduating from the incubation. However, the incubating services sometimes fail to foster the independence of new startup companies, and raise the dependence of many companies on BICs. Thus, the dependence on BICs is a very important factor to understand the survival of the incubated startup companies after graduation from BICs. The purpose of this study is to identify the main factors that influence the firm's dependence on BICs and to characterize the relationships among the identified factors. The business incubating service is a core construct of this study. It includes various activities and resources, such as offering the physical facilities, legal service, and connecting them with outside organizations. These services are extensive and take various forms. They are provided by BICs directly or indirectly. Past studies have identified various incubating services and classify them in different ways. Based on the past studies, we classify the business incubating service into three categories as mentioned above : (1) business infrastructure support, (2) direct support, and (3) networking support. The business infrastructure support is to provide the essential resources to start the business, such as physical facilities. The direct support is to offer the business resources available in the BICs, such as human, technical, and administrational resources. Finally, the indirect service was to support the resource in the outside of business incubation center. Dependence is generally defined as the degree to which a client firm needs the resources provided by the service provider in order to achieve its goals. Dependence is generated when a firm recognizes the benefits of interacting with its counterpart. Hence, the more positive outcomes a firm derives from its relationship with the partner, the more dependent on the partner the firm must inevitably become. In business incubating, as a resident firm is incubated in longer period, we can predict that her dependence on BICs would be stronger. In order to foster the independence of the incubated firms, BICs have to be able to manipulate the provision of their services to control the firms' dependence on BICs. Based on the above discussion, the research model for relationships between dependence and its affecting factors was developed. We surveyed the companies residing in BICs to test our research model. The instrument of our study was modified, in part, on the basis of previous relevant studies. For the purposes of testing reliability and validity, preliminary testing was conducted with firms that were residing in BICs and incubated by the BICs in the region of Gwangju and Jeonnam. The questionnaire was modified in accordance with the pre-test feedback. We mailed to all of the firms that had been incubated by the BICs with the help of business incubating managers of each BIC. The survey was conducted over a three week period. Gifts (of approximately ₩10,000 value) were offered to all actively participating respondents. The incubating period was reported by the business incubating managers, and it was transformed using natural logarithms. A total of 180 firms participated in the survey. However, we excluded 4 cases due to a lack of consistency using reversed items in the answers of the companies, and 176 cases were used for the analysis. We acknowledge that 176 samples may not be sufficient to conduct regression analyses with 5 research variables in our study. Each variable was measured through multiple items. We conducted an exploratory factor analysis to assess their unidimensionality. In an effort to test the construct validity of the instruments, a principal component factor analysis was conducted with Varimax rotation. The items correspond well to each singular factor, demonstrating a high degree of convergent validity. As the factor loadings for a variable (or factor) are higher than the factor loadings for the other variables, the instrument's discriminant validity is shown to be clear. Each factor was extracted as expected, which explained 70.97, 66.321, and 52.97 percent, respectively, of the total variance each with eigen values greater than 1.000. The internal consistency reliability of the variables was evaluated by computing Cronbach's alphas. The Cronbach's alpha values of the variables, which ranged from 0.717 to 0.950, were all securely over 0.700, which is satisfactory. The reliability and validity of the research variables are all, therefore, considered acceptable. The effects of dependence were assessed using a regression analysis. The Pearson correlations were calculated for the variables, measured by interval or ratio scales. Potential multicollinearity among the antecedents was evaluated prior to the multiple regression analysis, as some of the variables were significantly correlated with others (e.g., direct service and indirect service). Although several variables show the evidence of significant correlations, their tolerance values range between 0.334 and 0.613, thereby demonstrating that multicollinearity is not a likely threat to the parameter estimates. Checking some basic assumptions for the regression analyses, we decided to conduct multiple regression analyses and moderated regression analyses to test the given hypotheses. The results of the regression analyses indicate that the regression model is significant at p < 0.001 (F = 44.260), and that the predictors of the research model explain 42.6 percent of the total variance. Hypotheses 1, 2, and 3 address the relationships between the dependence of the incubated firms and the business incubating services. Business infrastructure service, direct service, and indirect service are all significantly related with dependence (β = 0.300, p < 0.001; β = 0.230, p < 0.001; β = 0.226, p < 0.001), thus supporting Hypotheses 1, 2, and 3. When the incubating period is the moderator and dependence is the dependent variable, the addition of the interaction terms with the antecedents to the regression equation yielded a significant increase in R2 (F change = 2.789, p < 0.05). In particular, direct service and indirect service exert different effects on dependence. Hence, the results support Hypotheses 5 and 6. This study provides several strategies and specific calls to action for BICs, based on our empirical findings. Business infrastructure service has more effect on the firm's dependence than the other two services. The introduction of an additional high charge rate for a graduated but allowed to stay in the BIC is a basic and legitimate condition for the BIC to control the firm's dependence. We detected the differential effects of direct and indirect services on the firm's dependence. The firms with long incubating period are more sensitive to indirect service positively, and more sensitive to direct service negatively, when assessing their levels of dependence. This implies that BICs must develop a strategy on the basis of a firm's incubating period. Last but not least, it would be valuable to discover other important variables that influence the firm's dependence in the future studies. Moreover, future studies to explain the independence of startup companies in BICs would also be valuable.

Effects of Alcohol on Psychomotor Performance and Subjective Assessments In Normal Adults with Variation of Acetaldehyde Dehydrogenase I (정상성인에서 ALDH-I의 변이가 알콜의 정신운동성 수행과 주관적 평가에 미치는 영향)

  • Yoon, Bo Hyun;Yoon, Jin Sang
    • Korean Journal of Biological Psychiatry
    • /
    • v.3 no.2
    • /
    • pp.222-239
    • /
    • 1996
  • The purpose of this study was to evaluate the effects of alcohol on the psychomotor performance and subjective assessment in healthy Korean adults with acetaldehyde dehydrogenase I(ALDH-I) isozyme variance. A total of 20 male subjects, half with active ALDH-I and the other half with inactive ALDH-I, were selected through both a self-reporting questionnaire examining alcohol sensitivity and the Higuchi's ethanol patch test detecting ALDH-I deficiency. In a doule-blind, placebo-controlled cross-over design, each subject consumed four doses of alcohol(0.25, 0.5, 0.75, 1.0g/kg) and placebo on five separate occasions at weekly intervals, Treatment order was fully balanced using a $5{\times}5$ Latin square, Psychomotor performance tests[coritical flicker fusion threshold(CFF) and choice reaction time(CRT)] and self-estimate questionnaires were conducted at baseline and at time points of 20, 40, 60, 90, 120, 150, 180 minutes after consuming the test drug for 20 minutes, Blood alcohol concentrations(BACs) using breath analyzer were measured at baseline and at time points of 10, 20, 30, 40, 50, 60, 75, 90, 105, 120, 150, 180 minutes after drinking, The BACs and the mean changes in the psychomotor performances and subjective assessments from pre-alcohol baseline, were compared between the two groups. The findings were summarized as follows : 1) BACs were tended to be higher in the inactive group than the active in all of the four alcohol doses. However significant group differences were only after the 0.5g/kg dose of alcohol. 2) The inactive group showed significant impairment in CFFT at most time points alter 0.75 and 1.0g/kg doses of alcohol. 3) In CRT, total reaction time(TRT) significantly prolonged in the inactive group than the active group at 20 minutes after 0.25 and 1.0g/kg doses of alcohol and at 40, 60, 90 minutes alter 0.75g/kg dose of alcohol. In the inactive group, recognition time component significantly increased at 20, 60, 90 minutes after 1.0g/kg dose of alcohol, while movement time component significantly increased at 40, 60 minutes after 0.75g/kg dose of alcohol. 4) Subjective evaluation of the effect of alcohol revealed that physical and mental conditions as well as a self-estimate of the effects of alcohol on performance were significantly worse in the inactive group than the active at some time points alter all of the lour alcohol doses, wihch were more pronounced after 0.75 and 1.0g/kg doses of alcohol. 5) Most of the group differences mentioned above, still remained statistically significant after BAC was entered as a covariate, These findings demonstrated that the alcohol sensitivity is higher in individuals with inactive ALDH-I than those with active ALDH-I both on the subjective assessments and the objective psychomotor performances. Furthermore, these results suggest thai the alcohol sensitivity may be determined by acetaldehyde concentration rather than BAC per se. In future studies, after more accurate genotyping for ALDH-I, the relationships between BAC, acetaldehyde concentration and alcohol sensitivities should be clearly defined.

  • PDF

A STUDY ON MICROLEAKAGE OF PIT AND FISSURE SEALANT AFTER ENAMEL SURFACE TREATMENT (법랑질 표면처리방법에 따른 치면열구전색재의 미세누출에 관한 비교연구)

  • Hyun, Hong-Keun;Kim, Jung-Wook;Lee, Sang-Hoon
    • Journal of the korean academy of Pediatric Dentistry
    • /
    • v.28 no.3
    • /
    • pp.512-521
    • /
    • 2001
  • Recently. the reintroduction of air-abrasion technology in dentistry has added a new potential method of pretreating teeth prior to placing sealants. The purpose of this in vitro study was to investigate microleakages of several pit and fissure sealants following various surface pre-treatment methods to the enamel, because there was a question concerning the validity of claim that this method was better than the conventional acid etching. Permanent molars were divided randomly into nine groups and treated accordingly: acid etching(group 1, 4, 7), air-abrasion(group 2, 5, 8), acid etching after air-abrasion(group 3, 6, 9). Then the authors placed and cured the three kinds of sealants(group $1\sim3$: Teethmate-F, group $4\sim6$: Ultraseal XT plus, group $7\sim9$: Denseal) according to the manufacturer's order. They were observed to determine the degree of microleakage. And these specimens were separated from the corresponding enamels and examined by Scanning Electron Microscope. The following results were obtained: 1. In comparing microleakage among tooth surface treatment methods, air-abrasion group(group 2, 5, 8) showed the greatest microleakage, while combination(air-abrasion + acid etching) group showed the least (p<0.05). However, no significant differences were found between group 7 and 9. 2. The mean microleakages were ranked as follows(p<0.05): In acid etching groups, group 7> group 4> group 1. In air-abrasive groups, group 8>groups 5> group 2. In combination groups, group 9>group 3> group 6. However, no significant differences were found between group 4 and 7 between group 2 and 5 and between group 3 and 6. 3. SEM showed that comparably longer resin tags were distributed regularly in acid etching groups and that shorter ones irregularly in air-abrasion groups. It also showed that these two kinds of tags were distributed simultaneously in combination groups.

  • PDF

Characterization of Sedimentation and pH Neutralization as Pretreatment of Acid Contaminated Water (산 오염수 전처리용 침전 및 중화 특성)

  • Im, Jongdo;Lee, Sangbin;Park, Jae-Woo
    • Journal of the Korean GEO-environmental Society
    • /
    • v.23 no.9
    • /
    • pp.33-40
    • /
    • 2022
  • Sedimentation and pH neutralization has been investigated as preteatment of acid contaminate water. The settling and neutralizing process derive more effective degradation efficiency as the pre-treatment process before the removal process of adsorption, volatile, biodegradation, or oxidation. Settling velocity, uniformity coefficient, coefficient of curvature, and grain size index can define in the sedimentation process for characteristics of the soil. The stainless steel sieve has been used to separate each particle size of the dry soil by assembling in order of 4, 10, 20, 40, 80, 100, and 200 mesh sizes. The soil from Gamcheon Port in Busan drops upper side of the sieve and shakes back and forth to separate each different size of the particle. The 1L of Imhoff cone and 200 mL of the mass cylinder were used as settling tanks to calculate settling velocity. Stokes' equation was used to figure out the average density of dry soil with a value from settling velocity. In the results, the average particle density and lowest settling velocity were 1.93 g/cm3 and 0.11 cm/s, respectively. These values can detect the range of settling points of sediment to prevent chemical accidents. In pH neutralization, the initial pH of 2, 3, 4, and 5 of nitric acid and sulfuric acid are used as an acid solution; 0.1, 0.01, and 0.001 M of sodium hydroxide and calcium hydroxide are used as a base solution. The main goal of this experiment is to figure out the volume percentage of the acid solution becomes pH 7. The concentration of 0.001 M of base solution exceeds all the conditions, 0.01 M exceeds partially, and 0.1 M does not exceed 5 v/v% except pH 2. Calcium hydroxide present less volume than sodium hydroxide at pH neutralization both sulfuric and nitric acid.