• Wind and Structures
• /
• 제12권3호
• /
• pp.179-204
• /
• 2009

A physical and numerical steady flow impinging jet has been used to simulate the bulk characteristics of a downburst-like wind field. The influence of downdraft tilt and surface roughness on the ensuing wall jet flow has been investigated. It was found that a simulated downdraft impinging the surface at a non-normal angle has the potential for causing larger structural loads than the normal impingement case. It was also found that for the current impinging jet simulations, surface roughness played a minor role in determining the storm maximum wind structure, but this influence increased as the wall jet diverged. However, through comparison with previous research it was found that the influence of surface roughness is Reynolds number dependent and therefore may differ from that reported herein for full-scale downburst cases. Using the current experimental results an empirical model has been developed for laboratory-scale impinging jet velocity structure that includes the influence of both jet tilt and surface roughness.

• Journal of applied mathematics & informatics
• /
• 제5권2호
• /
• pp.489-498
• /
• 1998

The influence of observations the on the goodness-of-fit test in maximum likelihood factor analysis is investigated by using the local influence method. under an appropriate perturbation the test statistic forms a surface. One of main diagnostics is the maximum slope of the perturbed surface the other is the direction vector cor-responding to the curvature. These influence measures provide the information about jointly influence measures provide the information about jointly influential observations as well as individ-ually influential observations.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1996년도 춘계학술대회 논문집
• /
• pp.697-703
• /
• 1996

Fatigue strength of high strengthsteels are variable with many different surface treatment. It is well known that residual compressive stress retard fatigue crack growth rate(or arrest crack). High strngth steels are manufactured by following process. Heat treatment, shot peening and chromium plating process. High strength steel(HRC40 or above) which are subjected to fatigue load and dynamic load, chromium plated parts shall be peened in accordance with requirements and baked after plating. The purpose of this paper is to compare and discuss the influence of surface treatment and hydrogen embrittlement on fatigue strength of high strength steel. Therefore, fatigue test was performed to investigate influence of surface treatment. The results shows that shot peening is very effect method in creasing fatigue life and after plating, baking process is essential to prevent hydogen failure. In this paper, the experimental investigation is made to clarify the influence of shot peening conditions and baking process on fatigue strength of high strength steel.

• 패션비즈니스
• /
• 제20권1호
• /
• pp.69-81
• /
• 2016

In this study investigated the effect of emotional labor, emotional exhaustion, and depression on the job-related attitudes. Sample subjects used in this study were salespeople of a fashion shop in Jeollabukdo and Jeollanamdo. Questionnaire data from 160 fashion shop salespeople were analyzed through a reliability analysis, factor analysis, and multiple regression analysis. The results of the study were as follows. First, emotional labor of salespeople was divided into 2 factors, surface acting and deep acting. Second, emotional labor had a significant influence on the emotional exhaustion and depression. Third, the surface acting of emotional labor had a positive influence on the emotional exhaustion and depression; whereas, the deep acting of emotional labor had a negative influence on the emotional exhaustion and depression. Fourth, the surface acting of emotional labor, emotional exhaustion, and depression had a negative influence on job involvement; in addition, the deep acting of emotional labor had a positive influence on job involvement. Fifth, the surface acting of emotional labor, emotional exhaustion, and depression had a positive influence on turnover intention; in addition, the deep acting of emotional labor had a negative influence on turnover intention.

• Tribology and Lubricants
• /
• 제39권6호
• /
• pp.273-277
• /
• 2023

This paper presents a molecular dynamics simulation-based numerical investigation of the influence of surface energy on water lubrication. Models composed of a crystalline substrate, half cylindrical tip, and cluster of water molecules are prepared for a tribological-characteristic evaluation. To determine the effect of surface energy on lubrication, the surface energy between the substrate and water molecules as well as that between the tip and water molecules are controlled by changing the interatomic potential parameters. Simulations are conducted to investigate the indentation and sliding processes. Three different normal forces are applied to the system by controlling the indentation depth to examine the influence of normal force on the lubrication of the system. The simulation results reveal that the solid surface's surface energy and normal force significantly affect the behavior of the water molecules and lubrication characteristics. The lubrication characteristics of the water molecules deteriorate with the increasing magnitude of the normal force. At a low surface energy, the water molecules are readily squeezed out of the interface under a load, thus increasing the frictional force. Contrarily, a moderate surface energy prevents expulsion of the water molecules due to squeezing, resulting in a low frictional force. At a high surface energy, although squeezing of the water molecules is restricted, similar to the case of moderate surface energy, dragging occurs at the soil surface-water molecule interface, and the frictional force increases.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 2002년도 추계학술대회 논문집
• /
• pp.319-323
• /
• 2002

Recently, new polishing system which was made by magnetic intelligent compound (MAGIC) was invented and, the study is going on for practical use the analysis of factors, that is, the kind of polishing grain, composition ratio of wheel elements, machining frequency, polishing pressure, which the main influence for polishing efficiency are the first step. In this study, analyzed influence of wheel raw material composition ratio on surface roughness.

• 동력기계공학회지
• /
• 제6권2호
• /
• pp.54-59
• /
• 2002

The principle of the FDM(fused deposition modeling) process is based on the layer by layer manufacturing technology, like other RP(rapid prototyping) process. In the FDM process, each layer may have different shape. Therefore, the built model may have stairs shape on its surface. This stairs shape is one of the serious problems in the FDM process. Thus in this study, cube models and spherical models were fabricated by FDM process to investigate the influence of injection amount on surface roughness. Models with various road width were also built to investigate the influence of road width on surface roughness. Surface roughness of the models was measured and analyzed. The result obtained in this study are expected to help selecting the part build orientation for optimum surface roughness.

• Corrosion Science and Technology
• /
• 제9권6호
• /
• pp.259-264
• /
• 2010

In continuous hot dip galvanizing process, oxide formation on steel surface has an influence on Zn wetting. High strength automotive steel contains high amount of Si and Mn, where Si-Mn composite oxides such as $Mn_2SiO_4$ or $MnSiO_3$ covers the surface after annealing. Zn wetting depends on how the aluminothermia reaction can reduce the Mn-Si composite oxides and then form inhibition layer such as $Fe_2Al_5$ on the steel surface. The outward diffusion of metallic ions such as $Mn^{2+}$, $Si^{2+}$ in the steel matrix is very important factor for the formation of the surface oxides on the steel surface. The surface state and grain boundaries provide an important role for the diffusion and the surface oxide reactions. Some elements such as P, Sb, and B have a strong affinity for the interface precipitation, and it influence the diffusivity of metallic ions on grain boundaries. B oxide forms very rapildly on the steel surface during the annealing, and this promote complex oxides with $SiO_2$ or MnO. P has inter-reacted with other elements on the grain boundaries and influence the diffusion through on them. Small addition of Sb could suppress the decarburization from steel surface and retards the formation of internal and external selective oxides on the steel surface. Interface control by the trace elements such as Sb could be available to improve the Zn wettability during the hot dip galvanizing.

• 한국프랜차이즈경영연구
• /
• 제6권2호
• /
• pp.51-66
• /
• 2015

As competition for better service between corporations is getting fierce, many efforts to improve service quality are being made endlessly. The quality of service is directly associated with customer satisfaction and the employee performance of emotional labor is a key factor to attain a high level of customer review and better corporation image. This study examines an influence of emotional labor on job stress and customer orientation in the context of a service franchise firm. The results are as follow. First, deep acting of emotional labor has a negative influence on job stress, and surface acting of emotional labor has a negative influence on customer orientation. Also, job stress has a negative influence on customer orientation. Second, deep acting of emotional labor does not have a positive influence on customer orientation. Third, surface acting of emotional labor does not have a positive influence on job stress. The findings of this study show that deep acting of service based on an employee emotion can produce the employee's better service attitude by decreasing employees' job stress, but standardized surface acting of service cannot. Therefore, franchisor needs to use employees' deep acting to improve the franchisee service quality.

• 한국기계가공학회지
• /
• 제1권1호
• /
• pp.23-28
• /
• 2002

Fused deposition modelling(FDM) is a rapid prototyping(RP) process that fabricates part layer by layer by deposition of molte thermoplastic material extrude from a nozzle. RP system has benefits. Benefit would be the ability to experiment with physical objects of any complexity m a relatively short period of time. But it has a matter of surface roughness and geometric accuracy. We study on Influence of tangent line angle on surface roughness at fused deposition.