• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.1
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• pp.40-47
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• 2000

A model for the prediction of combustion and exhaust emissions of DI diesel engine has been formulated and developed. This model is a quasi-dimensional phenomenological one and is based on multi-zone combustion modelling concept. This model is developed based on the concept of Hiroyasu's multizone combustion models. It takes nozzle injection (spray) parameters, induction swirl into consideration and the models of zone velocity, air entrainment, fuel droplet evaporation and mixture combustion are upgraded. Various parameters, such as cylinder pressure, heat release rate, Nox and soot emission, and these parameters in the zone are simulated. The results are compared with the experimental ones, too.

• Journal of Environmental Science International
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• v.17 no.9
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• pp.993-1003
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• 2008

Interior space in most buildings is divided into several zones. The most important factors relating to the indoor air environment are temperature, airflow, humidity, and contaminant concentration. An integrated multizone model to predict these environmental factors simultaneously was developed. Also, a computer program for this model was written by the language of VISUAL BASIC. The proposed model was applied to a apartment with five rooms that had been tested by Chung. Comparison of predicted results by this study with measured results by Chung showed that their variations were within 14% for airflow rates, 1% for temperatures, 12% for humidities, and 5% for concentrations. It was seen that the opening operation schedule of building has a significant effect on the air moisture md contaminant removal. Thus, this model may be available for predicting the indoor air environment and may be contributed to design the ventilation plan for controling of indoor air quality.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.45-50
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• 2005

The supply outdoor airflow rates are calculated and analyzed using a multizone network model in a high-rise residential apartment. The system parameters include parameters related to weather conditions, building conditions, operation conditions, and facility conditions. Simulations are conducted according to the method of design of experiments and analysis of variance is conducted to investigate the effects of parameters on ventilation rate. A correlation equation is derived to predict ventilation rates of the building depending on the various parameters.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.11
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• pp.813-822
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• 2012

In this study, the multizone simulation for biosafety of BSL3 lab. and energy simulation are carried out simultaneously by using linked model of CONTAM and TRNSYS. In BSL3 lab., annual energy consumption is approximately five to ten times more than the magnitude of the office building. This is because required air change rate is extremely large and it is difficult to maintain room pressure difference efficiently. To maintain pressure difference between laboratory rooms through sealing condition of doors and proper airflow control is significant. In this study, to predict indoor environment of the BSL3 lab.(Influenza A research lab.), the multizone simulation for four kinds of biohazard scenario is also performed as part of risk assessment. Multizone and energy simulation results by using linked model show that these approaches are used as a tool for the energy efficient design and operation method for the safer BSL3 lab. facilities.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.10
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• pp.534-539
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• 2013

In general, entire supply air of the BSL3 laboratory should be vented to the outside for its biosafety and the air conditioning system should always be operating to maintain a room pressure difference. In this regard, annual energy consumption is approximately five or ten times greater than the magnitude of the office building. In addition, to adjust room pressure difference to the set value efficiently, the supply and exhaust duct system are installed in each room of the BSL3 lab. Thus, initial construction cost is extremely high. In this study, multizone simulation is performed to estimate maintaining the appropriate room pressure difference in the case of changing model A (each room supply and exhaust system) to model B (each zone supply and exhaust system) for verification of the BSL3 lab biosafety. Also, in the case of these two models, the multizone simulation for three kinds of biohazard scenario is performed as part of risk assessment. The analysis of initial construction cost of two models is conducted for comparison. According to the studies, initial construction cost of model B is less than about 22% of existing model A. Moreover, biosafety of the BSL3 lab is still maintaining in the case of the two models.

• Journal of Environmental Science International
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• v.19 no.2
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• pp.125-136
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• 2010

The most important factors relating to the indoor air environment are temperature, airflow, humidity, and contaminant concentration. A sensitivity analysis of indoor environment factors was carried out to grasp influences along with changes of atmospheric conditions. An integrated multizone model was used to predict these sensitivities. This model was applied to an apartment with six zones. Airflow rates are influenced very seriously by changes of wind direct or wind velocity, but are influenced very slightly by changes of outdoor air temperature and are not influenced at all by changes of outdoor air humidity or contaminant concentration. Indoor air temperatures are influenced very directly by changes of outdoor air temperature, but are influenced very slightly by wind direction or wind velocity and are not influenced at all by changes of outdoor air humidity or contaminant concentration. Indoor air humidities are influenced very directly by changes of outdoor air humidity, but are not influenced at all by changes of outdoor air contaminant concentration and have little or no influence by changes of wind direction, wind velocity, or outdoor air temperature. Indoor air contaminant concentrations are influenced very seriously by changes of wind direct or wind velocity, but are influenced somewhat by changes of outdoor air contaminant concentration and are influenced very slightly by changes of outdoor air temperature and are not influenced at all by changes of outdoor air humidity.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.1
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• pp.77-85
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• 2007

One of the most common approaches to achieve better thermal comfort with the radiant floor heating system is supply water temperature control, which is that supply water temperature is varied with outdoor air temperature. But the application of this control method was not easy, because there has been no way to determine the supply water temperature. So in this study, a comprehensive, yet simple calculation method to find out the required supply water temperature is suggested by combining the building heat loss equation and the heat emission model of hydronic radiant floor heating system for single zone. And then using this calculation method, the multizone control method is suggested and confirmed through the thermal simulation. It is shown that indoor air temperature is stably maintained around the set point.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.6
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• pp.615-622
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• 2010

In this study, a 0D multizone spray-combustion model is developed for the estimation of the performance and NOx emission of medium-sized direct-injection marine diesel engine. The developed combustion model is coupled with the commercial 1D cycle-simulation model, Boost, to analyze the entire engine system, including the intake and exhaust. The combustion model code was generated using Fortran90, and the model was coupled with Boost by connecting the generated code to a user-defined high-pressure cycle (UDHPC) interface. Simulation was performed for two injectors (8 holes and 10 holes) and two engine loads (50% and 100%), and the results of simulation were in good agreement with engine performance test.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.11
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• pp.933-940
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• 2006

In this study multi-zone modeling program CONTAM 2.4 developed by NIST is used for estimating the air disinfection rate of the interior of a room which is set up the indoor air disinfection system with filter and ultra violet germicidal irradiation (UVGI). Developed models those enable to predict the transmission of air home contagion such as bacteria and fungus generated in our daily life are useful model for designning air cleaning & ventilation system of building. Also, results indicate that these models are enable to compute the real situation that is almost impossible of carrying out experiment in an actual condition due to biohazard problems and suggest that engineers will use these models as a design tool for the future immune building system.

• The korean journal of orthodontics
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• v.53 no.2
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• pp.89-98
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• 2023

Objective: This study aimed to compare the mechanical and thermal properties in the anterior and posterior segments of new and retrieved specimens of a commercially available multizone superelastic nickel-titanium (NiTi) archwire. Methods: The following groups of 0.016 × 0.022-inch Bioforce NiTi archwires were compared: a) anterior and b) posterior segments of new specimens and c) anterior and d) posterior segments of retrieved specimens. Six specimens were evaluated in each group, by three-point bending and bend and free recovery tests. Bending moduli (Eb) were calculated. Furthermore, the new specimens were evaluated with scanning electron microscopy/energy-dispersive X-ray spectrometry. A multiple linear regression model with a random intercept at the wire level was applied for data analysis. Results: The forces in the posterior segments or new specimens were higher than those recorded in the anterior segments or retrieved specimens, respectively. Accordingly, Eb also varied. Higher austenite start and austenite finish (Af) temperatures were recorded in the anterior segments. No statistically significant differences were found for these temperatures between retrieved and new wires. The mean elemental composition was (weight percentage): Ni, 52.6 ± 0.5; Ti, 47.4 ± 0.5. Conclusions: The existence of multiple force zones was confirmed in new and retrieved Bioforce archwires. The retrieved archwires demonstrated lower forces during the initial stages of deactivation in three-point bending tests, compared with new specimens. The Af temperature of these archwires may lie higher than the regular intraoral temperature. Even at 2 mm deflections, the forces recorded from these archwires may lie beyond biologically safe limits.