• Asian-Australasian Journal of Animal Sciences
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• 제16권1호
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• pp.50-56
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• 2003

An experiment was carried out to compare the body weight, shank length, rectal temperature, comb area, abdominal fat, blood parameters and bone traits of capon, slip and intact birds in Taiwan country chicken cockerels. One hundred and sixty-six Taiwan country chicken cockerels were randomly assigned to caponized or intact male groups. Caponized birds were surgically altered at 10 weeks old and raised to 28 weeks old. At 28 weeks of age, the capons were separated into capon and slip groups, depending on the atrophy of the comb and wattle in size. The results showed that body weight and shank length in slips were significantly (p<0.05) greater than in intact birds. Intact birds had the highest (p<0.05）feather scores and the lowest (p<0.05) rectal temperature. Compared with intact birds and slips, capons had a significantly (p<0.05) smaller comb area. Bone percentage, stress and cortical thickness, and bone and ash calcium content and plasma testosterone concentration, in intact birds were the highest (p<0.05) followed by slips and capons. However, intact birds had the lowest (p<0.05) plasma ionized calcium and phosphorus concentrations. Bone and ash manganese contents in capons were significantly (p<0.05)lower than those in others. These findings support the hypothesis that androgenic effects on secondary sexual characteristics are stronger than anabolic growth promoting response. Androgens can directly influence calcium fluxes in male chickens. Caponized caused a reduction in the bone percentage, stress, cortical thickness and bone calcium content.

• Tribology and Lubricants
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• 제37권6호
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• pp.253-260
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• 2021

Metal pipes are used in a wide range of applications, from plumbing systems of large construction sites to small devices such as medical tools. When a liquid is enforced to flow through a metal pipe, a higher flow rate is beneficial for higher efficiency. Using high pressures can enhance the flow rate yet can be harmful for medical applications. Thus, we consider an optimal geometrical design to increase the flow rate in medical devices. In this study, we focus on cannulas, which are widely used small metal pipes for surgical procedures, such as liposuction. We characterize the internal flow rate driven by a negative pressure and explore its dependence on the key design parameters. We quantitatively analyze the suction characteristics for each design variable by conducting computational fluid dynamics simulations. In addition, we build a suction performance measurement system which enables the translational motion of cannulas with pre-programmed velocity for experimental validation. The inner diameter, section geometry, and hole configuration are the design factors to be evaluated. The effect of the inner diameter dominates over that of section geometry and hole configuration. In addition, the circular tube shape provides the maximum flow rate among the elliptical geometries. Once the flow rate exceeds a critical value, the rate becomes independent of the number and width of the suction holes. Finally, we introduce a slippery liquid-infused nanoporous surface (SLIPS) coating using nanoparticles and hydrophobic lubricants that effectively improves the flow rate and antifouling property of cannulas without altering the geometrical design parameter.

• 수산해양기술연구
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• 제59권1호
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• pp.85-98
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• 2023

This study analyzes the importance and implementation of countermeasures to reduce safety accidents that may occur during fishing in coastal gillnet fishing. Safety accidents that may occur in coastal gillnet fishing were classified into 56 measurement items in six areas: slips and trips, contact with machinery, falls, struck by object, musculoskeletal symptoms, and electrical shock. 35 fishermen belonging to coastal gillnet associations in Tongyeong and Namhae were selected as samples, and the importance and implementation of the proposed measurement items were investigated in the field. In addition, the results were evaluated visually by IPA analysis. As a result of the analysis, the importance of struck by object was the highest, and the implementation of slips and trips was the highest. On the other hand, prevention of musculoskeletal damage was found to be the lowest in both importance and implementation. The area with the most significant difference in importance and implementation by the classified area for measurement items was struck by object, and the area with the minor difference was slips and trips. Among the measurement items, the importance is highly recognized, but there are items with low implementation. To improve their level of implementation, countermeasures such as continuous education, economic support, and structural change of fishing boats should be prepared; moreover, policy support activities for implementation should be carried out.

• 대한기계학회논문집A
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• 제21권1호
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• pp.104-111
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• 1997

Accounting for the additional damages come out from non-proportional loading path effect, material damage according to crystal structure dependence was studied. Microscopic observations of damaged material by SEM(Scanning Electron Microscope) showed crystal structure dependence. Biaxial in-phase loaded specimens showed the slips of same direction, which pararell each other, but biaxial 90.deg. out-of-phase loaded specimens showed multiply crossed slips. S. H. Doong and D. F. Socie reported that wavy/planar or planar slip material showed the increase in the cyclic hardening level during non-proportional cycling. From these results, the additional hardening and non-proportional loading effects were related with slip mechanism, and the slip mechanism was related with crystal structure. In the present study, a damage mechanism which accounts for the non-proportional loading effect from crystal structure dependence was considered and applied to A17075-T651.

• Korean Journal of Geomatics
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• 제3권2호
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• pp.129-140
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• 2004

This paper addresses solutions th the challenges of carrier phase integer ambiguity resolution and cycle slip detection/identification, for maintaining high accuracy of an integrated GPS/Pseudolite/INS system. Such a hybrid positioning and navigation system is an augmentation of standard GPS/INS systems in localized areas. To achieve the goal of high accuracy, the carrier phase measurements with correctly estimated integer ambiguities must be utilized to update the system integration filter's states. The contribution presents an effective approach to increase the reliability and speed of integer ambiguity resolution through using pseudolite and INS measurements, with special emphasis on reducing the ambiguity search space. In addition, an algorithm which can effectively detect and correct the cycle slips is described as well. The algorithm utilizes additional position information provided by the INS, and applies a statistical technique known as th cumulative-sun (CUSUM) test that is very sensitive to abrupt changes of mean values. Results of simulation studies and field tests indicate that the algorithms are performed pretty well, so that the accuracy and performance of the integrated system can be maintained, even if cycle slips exist in the raw GPS measurements.

• Tribology and Lubricants
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• 제23권1호
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• pp.9-13
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• 2007

Despite numerous researches on atomic-scale friction have been carried out for understanding the origin of friction, lots of questions about sliding friction still remain. It is known that friction at atomic-scale always shows unique phenomena called 'stick-slips' which reflect atomic lattice of a scanned surface. In this work, experimental study on the effects of system stiffnesses and load on the atomic-scale stick-slip friction of graphite was performed by using an Atomic Force Microscope and various cantilevers/tips. The objective of this research is to figure out the dependency of atomic-scale friction on the nanomechanical properties in sliding contact such as load, stiffness and contact materials systematically. From this work, the experimental observation of transitions in atomic-scale friction from smooth sliding to multiple stick-slips in air was first made, according to the lateral cantilever stiffness and applied normal load. The superlubricity of graphite could be verified from friction vs. load experiments. Based on the results, the relationship between the stickslip behaviors and contact stiffness was carefully discussed in this work. The results or this work indicate that the atomic-scale stick-slip behaviors can be controlled by adjusting the system stiffnesses and contact materials.

• 한국직업건강간호학회지
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• 제20권2호
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• pp.172-184
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• 2011

Purpose: The aim of this study is to identify the characteristics of occupational accidents by work type among municipal sanitation workers. Methods: The original data of occupational accidents in 2009 by Korea Occupational Safety & Health Agency were analyzed by frequency and percentage using the SAS Version 9.1. Results: The types of occupational accident were as follows: slips and trips, falls, musculoskeletal disorders, traffic accident, collision, amputation, cut & puncture, crush injuries, strenuous movement and drop/fly. Slips and trips occurred most frequently in domestic waste collection and street sweeping. The traffic accident showed the highest incidence in food waste collection. Falls occurred most frequently in recycling waste collection. Musculoskeletal disorders showed the highest incidence in large waste collection. Conclusion: Depending on the work type, types of occupational accident were different. The results of this study can provide the information for the development of the occupational accident prevention programs of municipal sanitation workers.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2006년 창립20주년기념 정기학술대회 및 국제워크샵
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• pp.294-297
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• 2006

The rail clamp is the device to prevent the crane slips along a rail from the wind blast as well as to locate a container crane in the set position during an operating mode. In this study we conduct the research for determining the proper position of supporter to prevent the overload applied to the rail clamp with respect to the wedge angle in the wedge type rail clamp. The friction force between the jaw pad and the rail to prevent that the crane slips along a rail, when the wind blows, is generated fly the rail-directional wind load. Accordingly the proper position of the supporter to prevent the overload is determined fly analyzing the forces applied to the rail clamp in the wedge working stage. In order to analyze the effect of the wedge angle on the position of supporter, 5-kinds of wedge angles, such as 2, 4, 6, 8, $10^{\circ}$, were adapted as the design parameter, and the wind speed of 40m/s was adapted as the design wind speed criteria.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.186-186
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• 2000

In the GPS/DR integrated system, the GPS position(or velocity) is used to compensate the DR output and to calibrate errors in the DR sensor. This synergistic relationship ensures that the calibrated DR accuracy can be maintained even when the GPS signal is blocked. Because of the observability problem, however, the DR sensors are not sufficiently calibrated when the vehicle speed is low. This problem can be solved if we use a multi-antenna GPS receiver for attitude determination instead of conventional one. This paper designs a two-antenna GPS receiver integrated with DR sensors. The proposed integration system has three remarkable features. First, the DR sensor can be calibrated regardless of the vehicle speed with the aid of two-antenna GPS receiver. Secondly, the search space of integer ambiguities in GPS carrier-phase measurements is reduced to a part of the surface of the sphere using DR heading. Thirdly, the detection resolution of cycle-slips in GPS carrier-phase measurements is improved with the aid of DR heading. From the experimental result, it is shown that the search grace is drastically reduced to about 3120 of the non-aided case and the cycle-slips of 1 or half cycle can be detected.

• 한국세라믹학회지
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• 제55권4호
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• pp.352-357
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• 2018

The slip casting process is widely used to make green bodies from ceramic slips into dense compacts with homogeneous microstructure. However, stress may be generated inside the green body during drying, and can lead to cracking and bending during sintering. When starting from the spherical powders with mono-size distribution to make the close packed body, interstitial voids on octahedral and tetrahedral sites are formed. In this research, experiments were carried out with powders of three size types (host powder (H), octahedral void filling powder (O) and tetrahedral void filling powder (T)) controlled for average particle size by milling from two commercial alumina powders. Slips were prepared using three different powder batches from H only, H+O or H+O+T mixed powders. After manufacturing green compacts by solid-casting, compacts were dried at constant temperature and humidity and sintered at $1650^{\circ}C$. Alumina samples fabricated from the multi-sized powder mixture had improved compacted and sintered densities.