• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.40 no.6
• /
• pp.31-38
• /
• 2003

A 16-bit adiabatic low-power Microprocessor is designed. The processor consists of control block, multi-port register file, program counter, and ALU. An efficient four-phase clock generator is also designed to provide power clocks for adiabatic processor. Adiabatic circuits based on efficient charge recovery logic(ECRL), are designed 0.35,${\mu}{\textrm}{m}$ CMOS technology. Conventional CMOS processor is also designed to compare the energy consumption of microprocessors. Simulation results show that the power consumption of the adiabatic microprocessor is reduced by a factor of 2.9∼3.1 compared to that of conventional CMOS microprocessor.

• Transactions of Materials Processing
• /
• v.12 no.4
• /
• pp.358-363
• /
• 2003

Adiabatic shear bands have been observed in the serrated chip during high strain rate metal cutting process of medium carbon steel and titanium alloy The recent microscopic observations have shown that dynamic recrystallization occurs in the narrow adiabatic shear bands. However the conventional flow stress models such as the Zerilli-Armstrong model and the Johnson-Cook model, in general, do not predict the occurrence of dynamic recrystallization (DRX) in the shear bands and the thermal softening effects accompanied by DRX. In the present study, a strain hardening and thermal softening model is proposed to predict the adiabatic shear localized chip formation. The finite element analysis (FEA) with this proposed flow stress model shows that the temperature of the shear band during cutting process rises above 0.5Τ$_{m}$. The simulation shows that temperature rises to initiate dynamic recrystallization, dynamic recrystallization lowers the flow stress, and that adiabatic shear localized band and the serrated chip are formed. FEA is also used to predict and compare chip formations of two flow stress models in orthogonal metal cutting with AISI 1045. The predictions of the FEA agreed well with the experimental measurements.s.

• Journal of the Korea Institute of Building Construction
• /
• v.16 no.2
• /
• pp.185-192
• /
• 2016

The semi-adiabatic calorimetry technique is a robust and easy technique that can be used to measure the temperature rise of concrete. This method is often used for investigating the maturity of concrete, as well as to predict maximum temperature rise of mass concrete using various heat loss compensating models. Semi-adiabatic calorimetry can also be used for predicting setting time of concrete. However, it has seldom been used to investigate the hydration characteristics of various cement paste samples. In this research, semi-adiabatic calorimetry and X-ray diffraction methods were used to investigate the hydration characteristics of 3 different ASTM type I Portland cements. First derivative of temperature rise (dT/dt) curve was used to isolate individual peaks. Based on the results of the experiments, a combination of dT/dt curve with XRD could be used to successfully identify hydration at a specific time period, showing its potential to be used as an alternative tool for hydration studies of cement-based materials.

• Proceedings of the KSME Conference
• /
• 2004.04a
• /
• pp.1243-1249
• /
• 2004

This study is focused on the comparison between the internal saturation temperature of the working fluid and the surface temperature of adiabatic zone of two-phase closed thermosyphons with various helical grooves. Distilled water, methanol and ethanol have been used as the working fluid. In the present work, a copper tube of the length of 1200mm and 14.28mm of inside diameter is used as the container of the thermosyphon. Each of the evaporator and the condenser section has a length of 550mm, while the remaining part of the thermosyphon tube is adiabatic section. A experimental study was carried out for analyzing the performances of having 50, 60, 70, 80, 90 helical grooves. A plain thermosyphon having the same inner and outer diameter as the grooved thermosyphons is also tested for the comparison. The results show that the numbers of grooves and the type of working fluids are very important factors for the operation of thermosyphons. A good agreement between the internal saturation temperature of working fluid and the surface temperature of adiabatic zone of two-phase closed thermosyphons with various helical grooves is obtained.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.38 no.4
• /
• pp.285-291
• /
• 2001

An 8-b$\times$8-b adiabatic pipelined multiplier is designed. Simplified four phase clock generator is also designed to provide supply clocks for adiabatic circuits. All the clock line charge on the capacitive interconnections is recovered to save energy. Adiabatic circuits are designed based on ECRL(efficient charge recovery logic) and are integrated using 0.6${\mu}{\textrm}{m}$ CMOS technology. The efficiency of proposed supply clock generator is better than the previous one by 4~11%. Simulation results show that the power consumption of adiabatic pipelined multiplier is reduced by a factor of 2.6~3.5 compared to a conventional pipelined CMOS multiplier.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2002.05a
• /
• pp.187-190
• /
• 2002

To study adiabatic shear band formation of tungsten heavy alloys, 5 prismatic specimens are loaded by high velocity impacts and treated as plane strain problems. Their volume percent of tungsten particles in WHA are 81%, 93% and 97% respectively and for the fixed 81% volume percent, small size particle model, large size particle model, undulated particle models are considered and then, the effects of particle's volume ratio, geometry and size to the formation of shear band are discussed.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2001.05a
• /
• pp.527-532
• /
• 2001

The crack of concrete induced by a temperature rise in early age concrete due to the heat of ration of cement is a serious problem for massive or high strength concrete structures. However, re is still no reasonable equations for the prediction of the temperature rising. On this study, the prediction equations of the heat of hydration of different types of binder are pained from the adiabatic temperature rise test, and compared with the results from different nations to obtain the best approximated equation. The strengths of concrete of which specimens were placed in the same chamber for the adiabatic to were compared with those under standard curing.

• The KSFM Journal of Fluid Machinery
• /
• v.10 no.2 s.41
• /
• pp.22-31
• /
• 2007

This paper describes the shape optimization of rotor blade in a transonic axial compressor rotor. Three surrogate models, Kriging, radial basis neural network and response surface methods, are introduced to find optimum blade shape and to compare the characteristics of object function at each optimal design condition. Blade sweep, lean and skew are considered as design variables and adiabatic efficiency is selected as an objective function. Throughout the shape optimization of the compressor rotor, the predicted adiabatic efficiency has almost same value for three surrogate models. Among the three design variables, a blade sweep is the most sensitive on the object function. It is noted that the blade swept to backward and skewed to the blade pressure side is more effective to increase the adiabatic efficiency in the axial compressor Flow characteristics of an optimum blade are also compared with the results of reference blade.

• Journal of Environmental Science International
• /
• v.11 no.9
• /
• pp.857-863
• /
• 2002

The meteorological elements were measured to investigate cause of summertime ice formation at Unchiri, Gangwon Province. The cause of freezing at valley was conformed as adiabatic expansion theory, latent heat of evaporation, natural convective theory, cold air remain theory, and convective freezing theory according to former study. However nither theory produced a satisfactory explanation. This studying area is not valley but ridge, and underground water surface exists at below than freezing height. wintertime temperature drop and summertime cold air spouting were explain as natural convective theory, generation of water drop on the rock was explained as cooling theory by air expansion, and ice formation on the rock was explained as adiabatic expansion theory. In conclusion, formation of ice valley at Unchiri was formed by natural convective theory, adiabatic expansion theory, and latent heat of evaporation successively.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1998.04a
• /
• pp.155-160
• /
• 1998

In this study, the estimation method of adiabatic temperature rise of concrete was developed by using hydration heat generation of mineral compounds of clinker and pozzolans. Specific heat considered the effects of mix proportion and temperature was calculated with experimental data. The adiabatic temperature rise calculated by developed method were compared with experiments in which many types of cement and admixtures were used. As the results of this study, it was found that the developed method could calculate adiabatic temperature rise of concrete accurately without the experiment.