• Title/Summary/Keyword: No Failures test

Search Result 69, Processing Time 0.021 seconds

Control Measures for Air Pollutant Emissions from In-Use Light-Duty Diesel Vehicles Regarding their Emission Control Technologies (배출허용기준 대응기술을 고려한 국내 소형 경유 운행차의 대기오염물질 관리 방안)

  • Lee, Taewoo;Park, Hana;Park, Junhong;Jeon, Sangzin;Kim, Jeongsoo;Choi, Kwangho
    • Journal of Korean Society for Atmospheric Environment
    • /
    • v.30 no.4
    • /
    • pp.327-338
    • /
    • 2014
  • The objective of this study is to enhance the effectiveness of Korean Inspection and Maintenance (I/M) program. Three main tasks are: to measure pollutant emissions of in-use light-duty diesel vehicles (LDVs); to evaluate the validity of existing smoke control scheme for low-smoke-emitting vehicles, which have diesel particulate filters, DPF, to meet stringent Euro-5 emission limits; and to assess the necessity and the benefit of $NO_x$ inspection, which is not involved in current I/M program. We measured second-by-second smoke, particulate and gaseous emissions of 27 LDVs using opacity smoke meter, photo-acoustic soot sensor, and portable emissions measurement system, respectively, under the Korean I/M test driving cycle, KD-147. We find that the DPF plays a key role in controlling soot, which can be considered as black carbon contained in particulate matter. Thus, from an I/M perspective, we believe smoke inspection strategies for Euro-5 diesel vehicles should be more focused on the capability of detecting DPF malfunctions or failures, in order to keep DPF properly functional. Fleet averaged distance-specific $NO_x$ emissions are consistently higher than corresponding emission limits, and the values are similar among pre-Euro-3, Euro-3, and Euro-4 vehicle fleets. These findings indicate that the $NO_x$ inspection should be incorporated into current I/M program in order to manage urban $NO_x$ emissions. This research allows the Korean I/M program keep pace with developments in vehicle technologies, as well as the increased emphasis on $NO_x$ with respect to air quality and human health.

Effects of direct and indirect bonding techniques on bond strength and microleakage after thermocycling (직접 부착법과 간접 부착법이 열순환 후 부착강도와 미세누출에 미치는 영향에 대한 연구)

  • Ozturk, Firat;Babacan, Hasan;Nalcaci, Ruhi;Kustarci, Alper
    • The korean journal of orthodontics
    • /
    • v.39 no.6
    • /
    • pp.393-401
    • /
    • 2009
  • Objective: The purpose of this study was to compare the shear bond strength (SBS) of brackets and microleakage of a tooth-adhesive-bracket complex bonded with a direct and an indirect bonding technique after thermocycling. Methods: Fifty non-carious human premolars were divided into two equal groups. In the direct bonding group a light-cured adhesive and a primer (Transbond XT) was used. In the indirect-bonding group, a light-cured adhesive (Transbond XT) and chemical-cured primer (Sondhi Rapid Set) were used. After polymerization, the teeth were kept in distilled water for 24 hours and thereafter subjected to thermal cycling (500 cycles). For the microleakage evaluation, 10 teeth from each group were further sealed with nail varnish, stained with 0.5% basic fuchsin for 24 hours, and examined under a stereomicroscope. Fifteen teeth from each group were used for SBS testing with the universal testing machine and adhesive remnant index (ARI) evaluation. Data were analyzed using the Mann-Whitney U test, Chi-square test, and Fisher's exact test. Results: There were no statistical differences on SBS and microleakage between the two bonding techniques. The indirect bonding group had a significantly lower ARI score. Bracket failures were obtained between enamel-resin interfaces. Conclusions: The type of bonding technique did not significantly affect the amount of microleakage and SBS.

Differential Effects of Recovery Efforts on Products Attitudes (제품태도에 대한 회복노력의 차별적 효과)

  • Kim, Cheon-GIl;Choi, Jung-Mi
    • Journal of Global Scholars of Marketing Science
    • /
    • v.18 no.1
    • /
    • pp.33-58
    • /
    • 2008
  • Previous research has presupposed that the evaluation of consumer who received any recovery after experiencing product failure should be better than the evaluation of consumer who did not receive any recovery. The major purposes of this article are to examine impacts of product defect failures rather than service failures, and to explore effects of recovery on postrecovery product attitudes. First, this article deals with the occurrence of severe and unsevere failure and corresponding service recovery toward tangible products rather than intangible services. Contrary to intangible services, purchase and usage are separable for tangible products. This difference makes it clear that executing an recovery strategy toward tangible products is not plausible right after consumers find out product failures. The consumers may think about backgrounds and causes for the unpleasant events during the time gap between product failure and recovery. The deliberation may dilutes positive effects of recovery efforts. The recovery strategies which are provided to consumers experiencing product failures can be classified into three types. A recovery strategy can be implemented to provide consumers with a new product replacing the old defective product, a complimentary product for free, a discount at the time of the failure incident, or a coupon that can be used on the next visit. This strategy is defined as "a rewarding effort." Meanwhile a product failure may arise in exchange for its benefit. Then the product provider can suggest a detail explanation that the defect is hard to escape since it relates highly to the specific advantage to the product. The strategy may be called as "a strengthening effort." Another possible strategy is to recover negative attitude toward own brand by giving prominence to the disadvantages of a competing brand rather than the advantages of its own brand. The strategy is reflected as "a weakening effort." This paper emphasizes that, in order to confirm its effectiveness, a recovery strategy should be compared to being nothing done in response to the product failure. So the three types of recovery efforts is discussed in comparison to the situation involving no recovery effort. The strengthening strategy is to claim high relatedness of the product failure with another advantage, and expects the two-sidedness to ease consumers' complaints. The weakening strategy is to emphasize non-aversiveness of product failure, even if consumers choose another competitive brand. The two strategies can be effective in restoring to the original state, by providing plausible motives to accept the condition of product failure or by informing consumers of non-responsibility in the failure case. However the two may be less effective strategies than the rewarding strategy, since it tries to take care of the rehabilitation needs of consumers. Especially, the relative effect between the strengthening effort and the weakening effort may differ in terms of the severity of the product failure. A consumer who realizes a highly severe failure is likely to attach importance to the property which caused the failure. This implies that the strengthening effort would be less effective under the condition of high product severity. Meanwhile, the failing property is not diagnostic information in the condition of low failure severity. Consumers would not pay attention to non-diagnostic information, and with which they are not likely to change their attitudes. This implies that the strengthening effort would be more effective under the condition of low product severity. A 2 (product failure severity: high or low) X 4 (recovery strategies: rewarding, strengthening, weakening, or doing nothing) between-subjects design was employed. The particular levels of product failure severity and the types of recovery strategies were determined after a series of expert interviews. The dependent variable was product attitude after the recovery effort was provided. Subjects were 284 consumers who had an experience of cosmetics. Subjects were first given a product failure scenario and were asked to rate the comprehensibility of the failure scenario, the probability of raising complaints against the failure, and the subjective severity of the failure. After a recovery scenario was presented, its comprehensibility and overall evaluation were measured. The subjects assigned to the condition of no recovery effort were exposed to a short news article on the cosmetic industry. Next, subjects answered filler questions: 42 items of the need for cognitive closure and 16 items of need-to-evaluate. In the succeeding page a subject's product attitude was measured on an five-item, six-point scale, and a subject's repurchase intention on an three-item, six-point scale. After demographic variables of age and sex were asked, ten items of the subject's objective knowledge was checked. The results showed that the subjects formed more favorable evaluations after receiving rewarding efforts than after receiving either strengthening or weakening efforts. This is consistent with Hoffman, Kelley, and Rotalsky (1995) in that a tangible service recovery could be more effective that intangible efforts. Strengthening and weakening efforts also were effective compared to no recovery effort. So we found that generally any recovery increased products attitudes. The results hint us that a recovery strategy such as strengthening or weakening efforts, although it does not contain a specific reward, may have an effect on consumers experiencing severe unsatisfaction and strong complaint. Meanwhile, strengthening and weakening efforts were not expected to increase product attitudes under the condition of low severity of product failure. We can conclude that only a physical recovery effort may be recognized favorably as a firm's willingness to recover its fault by consumers experiencing low involvements. Results of the present experiment are explained in terms of the attribution theory. This article has a limitation that it utilized fictitious scenarios. Future research deserves to test a realistic effect of recovery for actual consumers. Recovery involves a direct, firsthand experience of ex-users. Recovery does not apply to non-users. The experience of receiving recovery efforts can be relatively more salient and accessible for the ex-users than for non-users. A recovery effort might be more likely to improve product attitude for the ex-users than for non-users. Also the present experiment did not include consumers who did not have an experience of the products and who did not perceive the occurrence of product failure. For the non-users and the ignorant consumers, the recovery efforts might lead to decreased product attitude and purchase intention. This is because the recovery trials may give an opportunity for them to notice the product failure.

  • PDF

Cyclic Load Testing for Weak Axis Joints Connected with SRC Column and RC Beams (SRC기둥-RC보 약축방향 접합부 상세의 구조성능에 대한 실험적 연구)

  • Moon, Jeong-Ho;Lim, Jae-Hyung;Oh, Kyung-Hwan;Kim, Sung-Ho;Lee, Kang-Min
    • Journal of the Korea Concrete Institute
    • /
    • v.21 no.1
    • /
    • pp.37-45
    • /
    • 2009
  • An objective of this study is to evaluate the structural performance of the weak axis SRC column-RC beam joints by experiments. Although one of common joint types is the connection with standard hooks, it has been required to examine its safety and to settle problems of the joint among practical engineers. Specimen types are classified into two categories, namely the type of standard hook and the type of shape improvement. The first one is consisted of three specimens which are reference type, development length modification type, and development length supplement type. Three specimens for shape improvement were made with variations on the arrangement of longitudinal reinforcements and the development length. Test results based on cyclic loadings were discussed with load-deflection curves, maximum strengths, strength degradations beyond the maximum. It was found that the standard hook types showed premature failures and consequent strength degradations due to splitting of joint concrete. However, satisfactory performance was obtained with the shape improvement type with wing-plate welding. No premature failures and strength degradations were detected with the specimens.

A STUDY ON THE BOND STRENGTH OF REINFORCED INDIRECT COMPOSITE RESINS TO DENIAL ALLOYS (강화형 간접복합레진과 치과용 합금의 결합강도에 관한 연구)

  • Yoon, Dong-Joo;Shin, Sang-Wan;Lim, Ho-Nam;Suh, Kyu-Won
    • The Journal of Korean Academy of Prosthodontics
    • /
    • v.37 no.5
    • /
    • pp.620-639
    • /
    • 1999
  • Indirect composite resins are used as an popular effective esthetic material in prosthetic dentistry, often with metallic substructure that provides support for restorations. Recently, new indirect composite resins as a substitute of ceramic have been developed. These resins provide good esthetics, with a wide range of hue and chroma. And the flexural strength of those is in the range of 120-150MPa, Which is higher than that of feldspathic Ceramic, and similar th that of Dicor. Although it has many merits, one of the major clinical problems of composite resins is the bond failure between metal and resin due to insufficient interfacial bond strength. The purpose of this study was to evaluate shear bond strength of the reinforced indirect composite resin to dental alloys. Three different composite resin systems($Artglass^{(R)},\;Sculpture^{(R)},\;Targis^{(R)}$) as test groups and ceramic($VMK\;68^{(R)}$) as control group were bonded to Ni-Cr-Be alloy($Rexillium\;III^{(R)}$) and gold alloy(Deva 4). All specimens were stored at $^37{\circ}C$ distilled water for 24 hours and the half of specimens were thermocycled 2000 times at temperature from $5^{\circ}C\;to\;60^{\circ}C$. The shear bond strengths of reinforced indirect composite resins to dental alloys were measured by using the universal testing machine, and modes of debonding were observed by stereoscope and scanning electron microscope. The results were as follows: 1 The shear bond strengths of reinforced indirect composite resins to dental alloys were approximately half those of ceramic to dental alloys(P<0.01). 2. There was no significant difference between the shear bond strength of several reinforced indirect composite resins to metal. 3. Alloy type did not affect on the shear bond strengths of resin to metal, but the shear bond strengths of ceramic to gold alloys were higher than those of ceramic to Ni-Cr alloys(P<0.05). 4. The shear bond strengths of Artglass and Targil to gold alloys were significantly decreased after thermocycling treatment(P<0.01). 5. Sculpture showed cohesive, adhesive, and mixed failure modes, but Artglass and Targis showed adhesive or mixed failures. And ceramic showed cohesive and mixed failures.

  • PDF

MARGINAL MICROLEAKAGE AND SHEAR BOND STRENGTH OF COMPOSITE RESIN ACCORDING TO TREATMENT METHODS OF ARTIFICIAL SALIVA-CONTAMINATED SURFACE AFTER PRIMING (접착강화제 도포후 인공타액에 오염된 표면의 처리방법에 따른 복합레진의 번연누출과 전단결합강도)

  • Cho, Young-Gon;Ko, Kee-Jong;Lee, Suk-Jong
    • Restorative Dentistry and Endodontics
    • /
    • v.25 no.1
    • /
    • pp.46-55
    • /
    • 2000
  • During bonding procedure of composite resin, the prepared cavity can be contaminated by saliva. In this study, marginal microleakage and shear bond strength of a composite resin to primed enamel and dentin treated with artificial saliva(Taliva$^{(R)}$) were evaluated. For the marginal microleakage test, Class V cavities were prepared in the buccal surfaces of fifty molars. The samples were randomly assigned into 5 groups with 10 samples in each group. Control group was applied with a bonding system (Scotchbond$^{TM}$ Multi-Purpose plus) according to manufacture's directions without saliva contamination. Experimental groups were divided into 4 groups and contaminated with artificial saliva for 30 seconds after priming: Experimental 1 group ; artificial saliva was dried with compressed air only, Experimental 2 group ; artificial saliva was rinsed and dried. Experimental 3 group ; cavities were etched with 35% phosphoric acid for 15 seconds after rinsing and drying artificial saliva. Experimental 4 group ; cavities were etched with 35% phosphoric acid for 15 seconds and primer was reapplied after rinsing and drying artificial saliva. All the cavities were applied a bonding agent and filled with a composite resin (Z-100$^{TM}$). Specimens were immersed in 0.5% basic fuschin dye for 24 hours and embedded in transparent acrylic resin and sectioned buccolingually with diamond wheel saw. Four sections were obtained from one specimen. Degree of marginal leakage was scored under stereomicroscope and their scores were averaged from four sections. The data were analyzed by Kruscal-Wallis test and Fisher's LSD. For the shear bond strength test, the buccal or occlusal surfaces of one hundred molar teeth were ground to expose enamel(n=50) or dentin(n=50) using diamond wheel saw and its surface was smoothed with Lapping and Polishing Machine(South Bay Technology Co., U.S.A.). Samples were divided into 5 groups. Treatment of saliva-contaminated enamel and dentin surfaces was same as the marginal microleakage test and composite resin was bonded via a gelatin capsule. All specimens were stored in distilled water for 48 hours. The shear bond strengths were measured by universal testing machine (AGS-1000 4D, Shimaduzu Co., Japan) with a crosshead speed of 5 mm/minute. Failure mode of fracture sites was examined under stereomicroscope. The data were analyzed by ANOVA and Tukey's studentized range test. The results of this study were as follows : 1. Enamel marginal microleakage showed no significant difference among groups. 2. Dentinal marginal microleakages of control, experimental 2 and 4 groups were lower than those of experimental 1 and 3 groups (p<0.05). 3. The shear bond strength to enamel was the highest value in control group (20.03${\pm}$4.47MPa) and the lowest value in experimental 1 group (13.28${\pm}$6.52MPa). There were significant differences between experimental 1 group and other groups (p<0.05). 4. The shear bond strength to dentin was higher in control group (17.87${\pm}$4.02MPa) and experimental 4 group (16.38${\pm}$3.23MPa) than in other groups, its value was low in experimental 1 group (3.95${\pm}$2.51 MPa) and experimental 2 group (6.72${\pm}$2.26MPa)(p<0.05). 5. Failure mode of fractured site on the enamel showed mostly adhesive failures in experimental 1 and 3 groups. 6. Failure mode of fractured site on the dentin did not show adhesive failures in control group, but showed mostly adhesive failure in experimental groups. As a summary of above results, if the primed tooth surface was contaminated with artificial saliva, primer should be reapplied after re-etching it.

  • PDF

A Study of Reliability Analysis and Application on Naval Combat System Using Field Critical Failure Data (야전 치명고장자료를 이용한 함정전투체계 신뢰성 분석 및 활용 방안)

  • Kim, Young-Jin;Oh, Hyun-Seung;Choi, Bong-Wan
    • Journal of Korean Society of Industrial and Systems Engineering
    • /
    • v.39 no.4
    • /
    • pp.49-59
    • /
    • 2016
  • Naval combat system developed in-country is progressing at an alarming rate since 2000. ROK navy will be achieved all vessels that have combat system in the near future. The importance of System Engineering and Integrated Logistics Support based on reliability analysis is increasing. However, reliability analysis that everyone trusted and recognized is not enough and applied practically for development of Defense Acquisition Program. In particular, Existing Reliability Analysis is focusing on reliability index (Mean Time Between Failure (MTBF) etc.) for policy decision of defense improvement project. Most of the weapon system acquisition process applying in the exponential distribution simply persist unreality due to memoryless property. Critical failures are more important than simple faults to ship's operator. There are no confirmed cases of reliability analysis involved with critical failure that naval ship scheduler and operator concerned sensitively. Therefore, this study is focusing on Mean Time To Critical Failure (MTTCF), reliability on specific time and Operational Readiness Float (ORF) requirements related to critical failure of Patrol Killer Guided missile (PKG) combat system that is beginning of naval combat system developed in-country. Methods of analysis is applied parametric and non-parametric statistical techniques. It is compared to the estimates and proposed applications. The result of study shows that parametric and non-parametric estimators should be applied differently depending on purpose of utilization based on test of normality. For the first time, this study is offering Reliability of ROK Naval combat system to stakeholders involved with defense improvement project. Decision makers of defense improvement project have to active support and effort in this area for improvement of System Engineering.

Adhesion of 10-MDP containing resin cements to dentin with and without the etch-and-rinse technique

  • Turp, Volkan;Sen, Deniz;Tuncelli, Betul;Ozcan, Mutlu
    • The Journal of Advanced Prosthodontics
    • /
    • v.5 no.3
    • /
    • pp.226-233
    • /
    • 2013
  • PURPOSE. This study evaluated the adhesion of 10-MDP containing self-etch and self-adhesive resin cements to dentin with and without the use of etch-and-rinse technique. MATERIALS AND METHODS. Human third molars (N=180) were randomly divided into 6 groups (n=30 per group). Conventional (Panavia F2.0, Kuraray-PAN) and self-adhesive resin cements (Clearfil SA, Kuraray-CSA) were bonded to dentin surfaces either after application of 3-step etch-and-rinse (35% $H_3PO_4$ + ED Primer) or two-step self-etch adhesive resin (Clearfil SE Bond). Specimens were subjected to shear bond strength test using the universal testing machine (0.5 mm/min). The failure types were analyzed using a stereomicroscope and quality of hybrid layer was observed under a scanning electron microscope. The data (MPa) were analyzed using two-way ANOVA and Tukey's tests (${\alpha}$=.05). RESULTS. Overall, PAN adhesive cement showed significantly higher mean bond strength ($12.5{\pm}2.3-14.1{\pm}2.4$ MPa) than CSA cement ($9.3{\pm}1.4-13.9{\pm}1.9$ MPa) (P<.001). Adhesive failures were more frequent in CSA cement groups when used in conjunction with two-step self-adhesive (68%) or no adhesive at all (66%). Hybrid layer quality was inferior in CSA compared to PAN cement in all conditions. CONCLUSION. In clinical situations where bonding to dentin substrate is crucial, both conventional and self-adhesive resin cements based on 10-MDP can benefit from etch-and-rinse technique to achieve better quality of adhesion in the early clinical period.

A Study of Lupus Anticoagulants and Anticardiolipin Antibodies in Patients with Infertility and Recurrent Spontaneous Abortion (불임환자와 반복자연유산 환자에서 루프스 항응고인자와 항카디오리핀 항체에 대한 연구)

  • Nam, Yoon-Sung;Cha, Kwang-Yul;Baek, Jin-Young;Kim, Nam-Keun;Kang, Myung-Seo;Oh, Do-Yeon
    • Clinical and Experimental Reproductive Medicine
    • /
    • v.29 no.1
    • /
    • pp.29-35
    • /
    • 2002
  • Objective : To report the prevalence of lupus anticoagulants and anticardiolipin antibodies in patients with recurrent spontaneous abortion and infertility. Material and Method: Lupus anticoagulants and anticardiolipin antibodies were analyzed by Diluted Russell's Viper Venom Test (DRVVT) and solid phase enzyme immunoassay, respectively. Results : In 200 patients with infertility, there were 6 cases (3%) with positive lupus anticoagulants or anticardiolipin antibodies. Of these, 3 patients (1.5%) showed positive lupus anticoagulants and anticardiolipin antibodies, respectively. In 120 patients with recurrent spontaneous abortion, there were 13 cases (10.8%) of positive lupus anticoagulants or anticardiolipin antibodies. Of these, one patient (1%) showed lupus anticoagulants and 12 patients (10%) showed anticardiolipin antibodies. But in two groups, there was no cases with positive lupus anticoagulants and anticardiolipin antibodies. Conclusion: Lupus anticoagulants and anticardiolipin antibodies are definite cause of recurrent spontaneous abortion. There has been a speculation that they might be associated with infertility and repeated IVF failures. But it was found that the role of lupus anticoagulants and anticardiolipin antibodies in these cases are not clear.

Numerical investigations on stability evaluation of a jointed rock slope during excavation using an optimized DDARF method

  • Li, Yong;Zhou, Hao;Dong, Zhenxing;Zhu, Weishen;Li, Shucai;Wang, Shugang
    • Geomechanics and Engineering
    • /
    • v.14 no.3
    • /
    • pp.271-281
    • /
    • 2018
  • A jointed rock slope stability evaluation was simulated by a discontinuous deformation analysis numerical method to investigate the process and safety factors for different crack distributions and different overloading situations. An optimized method using Discontinuous Deformation Analysis for Rock Failure (DDARF) is presented to perform numerical investigations on the jointed rock slope stability evaluation of the Dagangshan hydropower station. During the pre-processing of establishing the numerical model, an integrated software system including AutoCAD, Screen Capture, and Excel is adopted to facilitate the implementation of the numerical model with random joint network. These optimizations during the pre-processing stage of DDARF can remarkably improve the simulation efficiency, making it possible for complex model calculation. In the numerical investigations on the jointed rock slope stability evaluations using the optimized DDARF, three calculation schemes have been taken into account in the numerical model: (I) no joint; (II) two sets of regular parallel joints; and (III) multiple sets of random joints. This model is capable of replicating the entire processes including crack initiation, propagation, formation of shear zones, and local failures, and thus is able to provide constructive suggestions to supporting schemes for the slope. Meanwhile, the overloading numerical simulations under the same three schemes have also been performed. Overloading safety factors of the three schemes are 5.68, 2.42 and 1.39, respectively, which are obtained by analyzing the displacement evolutions of key monitoring points during overloading.