• Journal of the Korean Society of Hazard Mitigation
• /
• v.11 no.3
• /
• pp.83-89
• /
• 2011

A series of full-scale testing was conducted to examine the effect of stairwell pressurization on the pressure differential between the stairwell and the auxiliary room and between the auxiliary room and the residence. Also, flow velocity profiles at open doors were measured. The building tested was a condominium that had twenty floors above the ground and two floors underground. For pressurization of the stairs, a blower was used to supply air into the stairwell at one location underground. Thirteen different cases were tested, and test variables included the number of floors with open doors and the flow rate of the air supply. When the doors on the first floor were open, the pressure differential between the stairwell and the auxiliary room was distributed almost uniformly except for locations near the first floor. When the flow rate was in the range of 180~270 CMM and the doors of one floor were open, the flow velocity could satisfy the requirement of fire safety standards and the stairwell pressure was positive at all levels. However, the minimum pressure requirement (10 Pa) could not always be satisfied. When doors on two floors were open, the flow velocity requirement could be satisfied by increasing the flow rate, but it was found impractical to satisfy the minimum pressure requirement without causing excessive pressure differential in the area near the blower.

• Applied Chemistry for Engineering
• /
• v.22 no.4
• /
• pp.429-432
• /
• 2011

The feasibility of applications of the char obtained from a gasification process of municipal-waste refuse derived fuel (RDF) as an auxiliary fuel was evaluated by combustion experiments. The higher heating value of the RDF char was 3000~4000 kcal/kg and its chlorine content was below the standard requirement demonstrating its potential as an auxiliary fuel. In the combustion exhaust gas, the maximum $NO_x$ and $SO_2$ concentrations were 240 ppm and 223 ppm, respectively. If an aftertreatment is applied, it is possible to control their concentrations low enough to meet the air pollutant emission standard. The HCl concentration was relatively high indicating that a care should be taken for HCl emission from the combustion of RDF. Based on the temperature distribution within the reactor, the concentration change of $O_2$ and $CO_2$, and the amount and the loss on ignition of solid residue, it was inferred that the combustion reaction was the most reliable when the excess air ratio of 1.3 was used.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.46 no.1
• /
• pp.70-81
• /
• 2010

A mathematical model is formulated to study the effect of wall mass on the thermal performance of four different houses of different construction. This analytical study was motivated by the experimental work of Burch et al. An analytical solution of one -dimensional, linear, partial differential equation for wall temperature profiles and room air temperatures is obtained using the Laplace transform method. Typical Meteorological Year data are processed to yield hourly average monthly values. These discrete data are then converted to a continuous, time dependent form using a Fast Fourier Transform method. This study is conducted using weather data from four different locations in the United States: Albuquerque, New mexico; Miami, Florida; Santa Maria, California; and Washington D.C. for both winter and summer conditions. A computer code is developed to calculate the wall temperature profile, room air temperature, and energy consumption loads. Three sets of results are calculated one for no auxiliary energy and two for different control mechanism -- an on-off controller and a proportional controller. Comparisons are made for the cases of two controllers. Heavy weight houses with insulation in mild weather areas (such as August in Santa Maria, California) show a high comfort level. Houses using proportional control experience a higher comfort level in comparison to houses using on-off control. The result shows that there is an effect of mass on the thermal performance of a heavily constructed house in mild weather conditions.

• Journal of ILASS-Korea
• /
• v.1 no.4
• /
• pp.46-53
• /
• 1996

The present study is aiming at improving the performance of main nozzle of an air jet loom with a modified reed and auxiliary nozzles. The double coaxial pipe jets consisting of a central air jet and an annular air jet have been experimentally investigated. The duter jet has a potential core and a constant velocity. The inner jet through an inner long pipe is induced by the subatmospheric pressure near the inner nozzle edge, and the jet velocity of an inner pipe is always lower than that of a outer pipe. The static pressures of the main nozzle over a wide range of the nozzle tank pressure were measured, and the nozzle velocity and Mach numbers were analytically calculated. Experiment81 results indicate that the critical condition of Mach number of unity to occur at the two positions in a main nozzle; one of them is the needle tip and the other is the acceleration tube exit An increase in the tank pressure causes the critical throat condition to occur at the two positions above. The velocity of acceleration-tube exit is maximum at the critical length L* and flow patter in acceleration-tube over critical lengh remains unstable.

• KIEAE Journal
• /
• v.10 no.6
• /
• pp.123-130
• /
• 2010

Indoor air quality has attracted great attention in recent years and thus the importance of managing finishing materials in terms of pollutant source control is being emphasized. Managing the finishing material at the design stage maximizes the efficiency of IAQ control at the following construction stage. However, there are insufficient investigations on the application of a specific finishing material management process, a database management system or a finishing material management process network. As a result, the main purposes of this study comprise comprehensive evaluation of IAQ performance from the selected finishing materials and auxiliary materials, application of the material management system basing on the types and characteristics of toxic substances generated from the indoor finishing materials, investigation of IAQ evaluation standard, and the overall IAQ evaluation method for the design parts. The result of this study will be the basic data to construct DBMS for management of finishing materials with respect to IAQ.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
• /
• v.12 no.4
• /
• pp.240-251
• /
• 1983

The municipal government of Daejeon, Korea set up a plan to retrofit solar energy to the existing swimming pool. The pool was constructed in 1980, and meets the requirements of International standard. It will be used for the 1986 Asian Games and the 1988 Seoul Olymipics. The roof structure of the existing pool is to be modified to accomodate trickle solar collectors. In addition, various energy conserving ideas will be applied to the existing building structure. For the prevention of over heating of collectors on the roof, natural air convection scheme will be adopted within the collector system. Natural convection of passive type heating would be also adopted for the space heating of the pool when the system is idle. At present, the pool can be utilized only for two months a year without auxilairy heating. With oil heating, the energy cost would be too high for the normal operation. When this project completed in March 1984, it would be expected to be openable for seven months a year without a significan amount of auxiliary heating. In this project, two dimensional numerical analysis technic have been used to analyse the characterisitics of thermal performance of the swimming pool system. An experimental tat verification of the theoretical analysis have been also attempted.

• Medical Lasers
• /
• v.8 no.2
• /
• pp.43-49
• /
• 2019

The plume produced by vaporizing tissue with a laser contains a variety of contaminants called laser-generated air pollutants (LGACs). LGACs consist of a mixture of toxic gas components, biomicroparticles, dead and living cells, and viruses. Toxic odors and thick smoke from surgical incisions and the coagulation of tissues can irritate eyes and airways, as well as cause bronchial and pulmonary congestion. Because of the potential risk of the smoke, it is advisable to appropriately remove it from the surgical site. We recommend using a smoke evacuator to remove the smoke. Suction nozzles should be placed as close as possible to the surgical site in a range of 2 cm or less. In-line filters should be used between the inlet and outlet of the surgical site. All air filtration devices should be capable of removing particles below 0.1 microns in size. The filter pack should be handled according to infection control procedures in the operating room. The laser mask can be an auxiliary protective device if it is properly worn. Some smoke inhaled under the nose wrap or over the side of the mask will not be filtered. As in electrosurgical operations, a suitable mask should be worn while smoke is present.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.19 no.1
• /
• pp.51-59
• /
• 2007

The waste bunker usually consists of waste entrance zone and waste pit. In this paper, the distributions of air flow, $NH_3$ concentration and $H_2S$ concentration in a waste bunker were investigated to prevent an odor generated in a waste pit from dispersing to the waste entrance zone by numerical method. Four cases were considered such that 1) the waste incinerators is operated, 2) the waste incinerators is stopped, 3) the waste incinerator is operated and the direction of a supply diffuser is $45^{\circ}$ upward, 4) the waste incinerator is stopped and the direction of a supply diffuser is $45^{\circ}$ upward. In case of 1), the fresh air from the waste entrance zone is exhausted smoothly to the main exhaust grill of the waste pit. It means that an odor dispersion to the waste entrance zone will not occur. However in case of 2), the induction of fresh air is so small and the supply air with an odor in waste pit can flow to the waste entrance zone. Therefore, an odor will be dispersed to the waste entrance zone. This paper shows the solution that the supply diffuser with the direction of $45^{\circ}$ upward is chosen. As a result in case of 3) and 4), an odor dispersion to the waste entrance zone does not occurred and on odor is exhausted smoothly to the auxiliary exhaust grill.

• Journal of Energy Engineering
• /
• v.10 no.3
• /
• pp.223-232
• /
• 2001

To study the stabilization characteristics of diffusion flame formed in the wake of a cylindrical bluff body with fuel injection, the flame stability limits, length and temperature of recirculation zone of flame, turbulence intensity distribution near the recirculation zone of flame were measured and analyzed. The length of recirculation zone is independent on main fuel injection quantity, but it is dependent on fuel injection angles, air stream velocity, and auxiliary fuel injection into recirculation zone. For diffusion flame, in general, the flame stabilization is deteriorated with increase of he length of recirculation zone, but if the turbulence generator is installed, the flame stabilization is improved with increase of the length of recirculation zone. The temperature of recirculation zone is dependent on fuel injection angles, auxiliary fuel injection into recirculation zone, turbulence generators, and it dependent on fuel injection angles, auxiliary fuel injection into recirculation zone, turbulence generators, and it has a maximum value at the condition of each theoretical mixture. In general, the more temperature of recirculation zone is low, the more flame is stable. But when the turbulence generator is installed, the more temperature of recirculation zone is low, the more flame is unstable. The turbulence intensity in the wake of bluff body is increased with increase of diameter or blockage ratio of grid. The more turbulence intensity is increased by installation of turbulence generator, the more flame is unstable. Finally, It is clear that the stabilization characteristics of diffuser flame can be controlled by some parameters such as fuel injection angles, auxiliary fuel injection into recirculation zone, turbulence generators.

• Journal of the Korean Society of Industry Convergence
• /
• v.17 no.3
• /
• pp.103-112
• /
• 2014

BY the Transformers and reactors, the input electrical energy is converted into magnetic energy. At the end through the magnetic energy was passed at the output parameter. Specially At the flyback transformer or a reactor airgap were designed to contain more magnetic energy. But that work is very difficult for the optimal design. It is that Contradictions are between the length of the Air-gap, Winding inductance, DC bias. As to e Several conflicting conditions in order to determine the optimum Air-gap has a lot of experience and trial & error is necessary. The approach proposed in this paper, the auxiliary winding on the core attached to part of primary core, that by applying a DC voltage has a dramatic effect like Core with designed Air-gap. This inventiveness and advantage is to regulate arbitrarily the Saturation Flux Quantity by the input signal to secondary winding. Accordingly obtained the biggest effect is that increasing limits of the saturation current destined by the material and shape of the conventional core. In other words, that can decreas the size of the transformer and reactor, While maintaining the current saturation capacity. This paper, prove its effect as using the local flux saturation in transformers and reactors for research by the computer program using the finite element method (FEM) simulation, followed by actual experiment to verify