• Journal of Mechanical Science and Technology
• /
• v.20 no.10
• /
• pp.1680-1690
• /
• 2006

As a promising and novel manufacturing technology, laser aided direct metal deposition (DMD) process produces near-net-shape functional metal parts directly from 3-D CAD models by repeating laser cladding layer by layer. The key of the build-up mechanism is the effective control of powder delivery and laser power to be irradiated into the melt-pool. A feedback control system using two sets of optical height sensors is designed for monitoring the melt-pool and real-time control of deposition dimension. With the feedback height control system, the dimensions of part can be controlled within designed tolerance maintaining real time control of each layer thickness. Clad nugget shapes reveal that the feedback control can affect the nugget size and morphology of microstructure. The pore/void level can be controlled by utilizing pulsed-mode laser and proper design of deposition tool-path. With the present configuration of the control system, it is believed that more innovation of the DMD process is possible to the deposition of layers in 3-D slice.

• Textile Coloration and Finishing
• /
• v.25 no.3
• /
• pp.232-239
• /
• 2013

In this study, 25gsm melt-blown polypropylene nonwoven for dust-proof/medical masks was finished by the corona discharging treatment. The influence of corona discharging parameters on the filtration efficiency was investigated. Several parameters such as discharging voltage, discharging speed, distance to discharging wire and configuration of discharging system had an effect on filtration efficiency, while the parameters had no effect on breathing resistance. Optimum corona discharging conditions are as follows: Wires were installed on the upper part of the nonwoven and paper pipe was installed on the lower part of the nonwoven having a distance of 5cm. The sequence of wire voltages was +60 kV, +60 kV, 0, -60 kV, and -60 kV. The discharging voltage and speed were 60 kV and 30m/min respectively. The nonwoven treated by corona discharging at the optimum condition showed a filtration efficiency of 80% or more, which is suitable for dust-proof/medical masks.

• Journal of Ocean Engineering and Technology
• /
• v.35 no.3
• /
• pp.238-246
• /
• 2021

The survivability of a naval ship is the ability of the ship and its onboard systems to remain functional and continue a designated mission in man-made hostile environments. A passive decoy system is primarily used as a weapon system for improving the survivability of a naval ship. In this study, an engagement scenario-based simulation program was developed for decoy effectiveness assessments against an anti-ship missile (ASM), which tracks a target with sea-skimming and active radar homing. The program can explain the characteristics of a target ship, such as the radar cross section and evasive maneuvers, as well as the operational performance of the onboard decoy system, the guidance method of the ASM, and the engagement environment's wind speed and direction. This paper describes the theory and formulations, configuration, and user interface of the developed program. Numerical examples of a decoy effect assessment of a virtual naval ship against an ASM are presented.

• Advances in nano research
• /
• v.13 no.5
• /
• pp.427-435
• /
• 2022

Static stability behaviors of annular sandwich plates constructed from two layers of particle-reinforced nanocomposites have been investigated in the present article. The type of nanoscale particles has been considered to be graphene oxide powders (GOPs). The particles are assumed to have uniform and graded dispersions inside the matrix and the material properties have been defined according to Halpin-Tsai micromechanical model. The core layer is assumed to have honeycomb configuration. Annular plate has been formulated according to thin shell assumptions considering geometrical nonlinearities. After solving the governing equations via Galerkin's technique, it is showed that the post-buckling curves of annular sandwich plates rely on the core wall thickness, amount of GOP particles, sector radius, and thickness of layers.

• Korean Institute of Interior Design Journal
• /
• v.20 no.6
• /
• pp.311-320
• /
• 2011

Public libraries in Korea have undergone changes from libraries for just reading or keeping books to libraries with cultural facilities that provide information through various media. It was because of the "plan for building the information-oriented library" in 2000 that made the complexation of public library in progress. The alterations of the system have changed the structure as well as the grade ranks but haven't been considered enough for administrators or visitors. Hereupon, we are to study of the features by analyzing how the application of the system changed the structure of library. There are four stages in research methods. First, concept of public library and functional elements requested in the process of complexation were studied from literature. Second, vertical, horizontal and circulate changes were studied by applying subject libraries into prior research stereotyping the libraries. Third, mutual relations between each place were studied through J-Graph by elements. Lastly, rank changes according to centrality of space and users were quantitatively studied with space syntax. 4 notable changes were found in these analyses. (1)Vertical, horizontal and circulate structure of public libraries were homogenized. Since 2001, however, they have become diversified as all-in-one or detachable. (2)The space structure of library before 2001 was shallow tree shape while in 2001, period of transition, was the tree shape mixed with ring shape. As time goes on, it has become shallow tree shape again but connected by ring shape in part of reading and common space and in digital reference room. (3)Digital reference room was center of the space around 2001 and it ranked top for integration. After 2007, however, it has become setting off-center. (4)About the purpose of using public libraries, using it as space for administrators ranked top followed by space for visitors and common space before. For now, common space ranks top and space for visitors and administrators. 5 subject public libraries were selected respectively before and after 2001.

• Korean Institute of Interior Design Journal
• /
• v.13 no.3
• /
• pp.129-136
• /
• 2004

The purpose of this study is to provide basic information and guide line for designing hotels located in metropolis by analyzing the spatial configuration of public area. As the sample of analysis, ten hotels are selected in Tokyo area, which were constructed during 1970 to 1990; the period was characterized by booming hotel constructions. The findings of the above analytical survey might be summarized as follows. First of all, it was found that all hotels constructed during the above mentioned periods could be classified into two categories according to their block type such as interlocking form and form within form types. It also observed the six hotels out of then had adopted form within form, beside, the left four hotels were constructed along the interlocking form type. Secondly, as regard to the functional space configuration of the public area, it was found that, in case of eight hotels, the upper part of the building which allocated as residential quarter are configured as linear type. As regard the lower part, however, it was found that different types are adopted. For instance, five hotels had adopted con-course types for the lower level that is spared for the public/service area. Beside, it was also found that, out of above five hotels, three hotels took form within type and the other two adopted compromising type. Thirdly, as regard to the composition of public area, it was found that, the quarters are allocated as follows, such as 34.11 percent for public, 28.99 percent for sales and 33.07 percent for service quarter.

• Journal of The Korea Institute of Healthcare Architecture
• /
• v.25 no.4
• /
• pp.81-91
• /
• 2019

Purpose: Since infectious disease hospitals are premised on emergency operations, the operational efficiency of secured personnel, equipment, facilities, etc. is relatively low. In order to increase such normal operational efficiency, it is necessary to flexibly operate facilities and operations during normal and emergency times. The purpose of this study is to suggest the architectural planning method focusing on the space composition and circulation of the regional infectious disease hospital which can increase the operational efficiency in the private hospitals. Methods: Through literature review, functional requirements of infectious disease hospitals were identified, and related personnels inter-views and field surveys were conducted to understand the spatial composition and circulation requirements of infectious disease hospitals. Results: Through the complete separation between the negative pressure zone and the general zone, even when the negative pressure zone is completely closed, the general zone should be operated separately to achieve operational efficiency. In addition, the separation of the negative pressure zone and the general zone should simultaneously consider the optimal space configuration and movement for each function while the zone settings match in the floor plan of each department and the overall cross-sectional configuration of the hospital. Implications: Infectious disease hospitals intended to be installed in private hospitals should not apply excessive space just for safety reasons and should plan to ensure their operational efficiency.

• Korean Institute of Interior Design Journal
• /
• v.17 no.1
• /
• pp.120-129
• /
• 2008

It requires great efforts to satisfy all functional characteristics of the rehabilitating treatments space for the specialized clinic for the elderly as the rehabilitating scope for treatment of the clinic has become more specialized and sectionalized. The specialization of the clinic for the elderly is saliently different in terms of rehabilitation treatment. The changed concept of rehabilitation for the elderly means that it places great importance in helping the elderly in their day-to-day life through a short-term or outpatient treatment, not a long term stay at hospital for retreat. The rehabilitation space in the clinic is essential in that it provided environment for efficient space placement in varied location. Thus, this study has been researched on 6 clinics for the elderly. It is because the space will have a variety of functions, which will be for the sake of the effective rehabilitation treatment of those aged patients who use that medical facilities, and not only for the physical therapy. It could have been designed to accommodate and realize not only the physical well-being, but also psychological, social and spiritual integrity for a variety of treatments, with which as the basis, this study theorizes the characteristics of the essential elements and the specialization factors by extracting spatial element through theoretical investigation. In conclusion the study here proposes the planned guideline for the rehabilitation treatment space to be designed inside the specialized clinic for the elderly, with renewed awareness of the importance on the spatial element in a recently established clinic.

• Journal of The Korea Institute of Healthcare Architecture
• /
• v.22 no.1
• /
• pp.51-61
• /
• 2016

Purpose: To improve and establish functions for public health centers in rural public, an analysis will be done on arrangement plan and area by function for public health centers in farming and fishing villages. After finding out this relationship and architectural characteristics, spatial organization and area ratio for providing efficient medical service and the relationship between the two will be examined. Methods: 8 of them were selected and site visit and interview with the person in charge were conducted to investigate the current status. The drawings collected for analysis were input as CAD data and schematized. The relationship between the arrangement type and area for the public health centers in farming and fishing villages was analyzed and based on this, an analysis was done on agricultural scale and characteristics, and putting these analyzed results together, an appropriate method of improvement was proposed for spatial organization by function for public health centers in farming and fishing villages and to provide efficient service. Results: Firstly, the Plan types found in the public health centers in farming and fishing villages could be classified into three including single-type, multiple-type and radial-type. Secondly, according to an analysis of areas by function, in the case of treatment function, there was a difference in the area ration for selective treatment. This ratio is considered to be greatly influenced by the project each public health center focuses on. Thirdly, I could become aware of the relationship between spatial organization and area ratio based on the analysis of arrangement and area derived above. Implication: As the data to refer to in future research on spatial organization for public health centers, if the object of analysis becomes more expanded and investigated, it will be utilized in detail for spatial planning of public health centers, thereby being expected to contribute to more efficient and qualitatively enhanced medical service provided by public health centers.

• Membrane and Water Treatment
• /
• v.10 no.2
• /
• pp.113-120
• /
• 2019

To investigate surface properties and interception performances of the new modified PVDF membrane coated with Graphene Oxide (GO) and nano-$TiO_2$ (for short the modified membrane) via the interface polymerization method combined with the pumping suction filtration way, filtration experiments of the modified membrane on Humic Acid (HA) were conducted. Results showed that the contact angle (characterizing the hydrophilicity) of the modified membrane decreased from $80.6{\pm}1.8^{\circ}$ to $38.6{\pm}1.2^{\circ}$. The F element of PVDF membrane surface decreased from 60.91% to 17.79% after covered with GO and $TiO_2$. O/C element mass ratio has a fivefold increase, the percentage of O element on the modified membrane surface increased from 3.83 wt% to 20.87%. The modified membrane surface was packed with hydrophilic polar groups (like -COOH, -OH, C-O, C=O, N-H) and a functional hydrophilic GO-polyamide-$TiO_2$ composite configuration. This configuration provided a rigid network structure for the firm attachment of GO and $TiO_2$ on the surface of the membrane and for a higher flux as well. The total flux attenuation rate of the modified membrane decreased to 35.6% while 51.2% for the original one. The irreversible attenuation rate has dropped 71%. The static interception amount of HA on the modified membrane was $158.6mg/m^2$, a half of that of the original one ($295.0mg/m^2$). The flux recovery rate was increased by 50%. The interception rate of the modified membrane on HA increased by 12% approximately and its filtration cycle was 2-3 times of that of the original membrane.