• Geomechanics and Engineering
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• v.21 no.2
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• pp.153-164
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• 2020

Tunnel excavation in shallow soft ground conditions of urban areas experiences inevitable surface settlements that threaten the stability of nearby infrastructures. Surface settlements during shield TBM tunneling are related to a number of factors including geotechnical conditions, tunnel geometry and excavation methods. In this paper, a database collected from a construction section of Hong Kong subway was used to analyze the correlation of settlement-inducing factors and surface settlements monitored at different locations of a transverse trough. The Pearson correlation analysis result revealed a correlation between the factors in consideration. Factors such as the face pressure, advance speed, thrust force, cutter torque, twin tunnel distance and ground water level presented a modest correlation with the surface settlement, while no significant trends between the other factors and the surface settlements were observed. It can be concluded that an integrated effect of the settlement-inducing factors should be related to the magnitude of surface settlements.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.6
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• pp.1651-1661
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• 2016

The purpose of this study is to draw up a plan for improving working conditions of distant water fishing vessel crew in order to revitalize the declining distant water fishing industry. Land-based employment has increased as the result of industrialization, which in turn created shortage in marine crew supply for distant water fishing vessels. Pressure on increasing wages for sea farers is put on the industry for this reason, making the labour market in the distant water fishing industry tougher and tighter. Multiple issues have yet to be addressed for distant water fishing vessel crew. They suffer from excessive work compared to other industries. Crew management is another issue, as sea farers face poor labour conditions, working on board vessels in a collective way where no autonomous actions are allowed. Other issues include unqualified crew supply, increasing ratio of labour costs for crew to sales, and intensified implications of labour unions, which are as well making crew supply difficult as a whole. To this end, more well-qualified workers should take part in production operations in the distant water fishery. Both wage increase and working condition improvement should be achieved in order to strengthen motivation towards qualified sea farers. Sustainable crew supply can be achieved when working environments, gender-based working conditions, welfare are prioritized and improved as a whole.

• Steel and Composite Structures
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• v.20 no.3
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• pp.513-543
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• 2016

Third order shear deformation theory is used to evaluate electro-elastic solution of a sandwich plate with considering functionally graded (FG) core and composite face sheets made of piezoelectric layers. The plate is resting on the Pasternak foundation and subjected to normal pressure. Short circuited condition is applied on the top and bottom of piezoelectric layers. The governing differential equations of the system can be derived using Hamilton's principle and Maxwell's equation. The Navier's type solution for a sandwich rectangular thick plate with all edges simply supported is used. The numerical results are presented in terms of varying the parameters of the problem such as two elastic foundation parameters, thickness ratio ($h_p/2h$), and power law index on the dimensionless deflection, critical buckling load, electric potential function, and the natural frequency of sandwich rectangular thick plate. The results show that the dimensionless natural frequency and critical buckling load diminish with an increase in the power law index, and vice versa for dimensionless deflection and electrical potential function, because of the sandwich thick plate with considering FG core becomes more flexible; while these results are reverse for thickness ratio.

• The Journal of Engineering Geology
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• v.13 no.4
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• pp.445-456
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• 2003

Backfill grouting and consolidation grouting are major reinforcing methods that enhance the stability of tunnel by filling the gap between the tunnel lining and the ground and increasing the stiffness of the ground. However, the effect of the grouting on the tunnel lining is not well established. Field measurements such as pressuremeter test, Lugeon test, and lining instruments were peformed to analyze the grouting effect on the tunnel lining for a waterway tunnel. The elastic modulus was increased up to 5 times than that of original rock mass due to consolidation grouting. This study shows that only 10% of grout pressure was acting on the back face of the tunnel lining. The final results are expected to be used for the design of the concrete lining.

• International Journal of Automotive Technology
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• v.8 no.5
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• pp.543-553
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• 2007

It is becoming increasingly difficult for engines using conventional fuels and combustion techniques to meet stringent emission norms. The homogeneous charge compression ignition(HCCI) concept is being evaluated on account of its potential to control both smoke and NOx emissions. However, HCCI engines face problems of combustion control. In this work, a single cylinder water-cooled diesel engine was operated in the HCCI mode. Diesel was injected during the suction stroke($0^{\circ}$ to $20^{\circ}$ degrees aTDC) using a special injection system in order to prepare a nearly homogeneous charge. The engine was able to develop a BMEP(brake mean effective pressure) in the range of 2.15 to 4.32 bar. Extremely low levels of NOx emissions were observed. Though the engine operation was steady, poor brake thermal efficiency(30% lower) and high HC, CO and smoke were problems. The heat release showed two distinct portions: cool flame followed by the main heat release. The low heat release rates were found to result in poor brake thermal efficiency at light loads. At high brake power outputs, improper combustion phasing was the problem. Fuel deposited on the walls was responsible for increased HC and smoke emissions. On the whole, proper combustion phasing and a need for a well- matched injection system were identified as the important needs.

• Archives of Plastic Surgery
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• v.45 no.1
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• pp.85-88
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• 2018

Local flaps exhibit excellent color matching that no other type of flap can compete with. Moreover, surgery using a local flap is easier and faster than surgery using a distant or free flap. However, local flaps can be much more difficult to design. We designed 2 templates to plan a V-Y rotation advancement flap. The template for a unilateral V-Y rotation advancement flap was used on the face (n=5), anterior tibia (n=1), posterior axilla (n=1), ischium (n=1), and trochanter (n=2). The template for a bilateral flap was used on the sacrum (n=8), arm (n=1), and anterior tibia (n=1). The causes of the defects were meningocele (n=3), a decubitus ulcer (n=5), pilonidal sinus (n=3), and skin tumor excision (n=10). The meningocele patients were younger than 8 days. The mean age of the adult patients was 50.4 years (range, 19-80 years). All the donor areas of the flaps were closed primarily. None of the patients experienced wound dehiscence or partial/total flap necrosis. The templates guided surgeons regarding the length and the placement of the incision for a V-Y rotation advancement flap according to the size of the wound. In addition, they could be used for the training of residents.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.5
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• pp.71-80
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• 2007

Because of the characteristics relating to high tensile ductility, High Performance Fiber Reinforced Cementitious Composites (HPFRCC) are studied to be adopted in repair and retrofit of buildings. A series of three shear wall specimens was tested under constant axial stress and reversed cyclic lateral loading in order to evaluate the seismic retrofit that had been proposed for the shear wall with the opening. The retrofit involved the use of newly developed ECC and MDF(Macro Defect Free), both of which are sprayed through the high pressure pump, over the entire face of the wall. The results indicate that two difference types of retrofitting strategy make the different effects of a rise in the strength and ductility of each specimen.

• Safety and Health at Work
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• v.10 no.2
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• pp.188-195
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• 2019

Background: Mine workers in South Africa face challenges relating to poor health and safety, including fatigue risks, and poor socioeconomic and living conditions. Fatigue results in impaired mental and physical performance. The aim of this study was to assess contributors to fatigue of mine workers in South Africa. Methods: Data collection took place at four gold mines and one platinum mine in South Africa. A total of 21 focus groups were held with individuals in management, union representatives, and mine workers, and 564 questionnaires were completed by mine workers to gather information about fatigue and potential contributors to fatigue at these mines. Results: Qualitatively (through focus groups), fatigue was attributed to extended working hours, harsh working conditions, high workloads, production pressure, and resource constraints, along with aspects relating to demographic and socioeconomic factors, living conditions, lifestyle, health, and wellness. Greater fatigue was significantly associated with younger age, indebtedness, a lack of exercise, poor nutrition, less sleep, increased alcohol use, poor self-reported health, more sick leave, higher stress, and lower job satisfaction. Conclusion: The aim of the study was achieved; numerous work-, sociodemographic-, lifestyle-, and wellness-related factors were linked to fatigue in the participating mine workers. Contributors to fatigue should be addressed to improve health, safety, and sustainability in the industry.

• Korea Trade Review
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• v.44 no.2
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• pp.221-237
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• 2019

Multinational corporations (MNCs) usually face indigenous business environments in host countries which are different from a home country's. In this circumstance, MNCs would accomplish low-investing performance if they pursuit the same as the home oriented business strategy in the host country. The more different kinds of specialized environments a host countries have, the more pressure of modifying the international strategy needed for MNCs. This paper examines that how a different market environment between a home country and a host country, through MNC's local responsive managements, can influence investing performance in a host country. This paper conducts structural equation analyses with collected empirical data focusing upon a MNC's market orientation efforts and the realization of management localization (i.e., increasing local sourcing intensity or local sales intensity) as mediators between the specialized environment in a host country and the MNC's investing performance. This paper has several contributions in developing the prior approaches: first, the market orientation variables are regarded not as normal independent factors but mediators; second, two step mediation model is examined to make link between host market's heterogeneity and MNC's performance.

• Geomechanics and Engineering
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• v.24 no.6
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• pp.531-543
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• 2021

Freezing and thawing of pore water within backfill can affect the stability of retaining wall as the phase change of pore water causes changes in the mechanical characteristics of backfill material. In this study, the effects of freezing and thawing on the mechanical performance of retaining wall with granular backfill were investigated for various temperature and groundwater level (GWL) conditions. The thermal and mechanical finite element analyses were performed by assigning the coefficient of lateral earth pressure according to phase change of soil for at-rest, active and passive stress states. For the at-rest condition, the mobilized lateral stress and overturning moment changed markedly during freezing and thawing. Active-state displacements for the thawed condition were larger than for the unfrozen condition whereas the effect of freezing and thawing was small for the passive condition. GWL affected significantly the lateral force and overturning moment (Mo) acting on the wall during freezing and thawing, indicating that the reduction of safety margin and wall collapse due to freezing and thawing can occur in sudden, unexpected patterns. The beneficial effect of an insulation layer between the retaining wall and the backfill in reducing the heat conduction from the wall face was also investigated and presented.