One of reinforcement bar treatment during delivery transportation is to bend up or buckle in the middle of the bar. This treatment will undermine the strength of the reinforcement bar on buckle region due to its mechanical properties have been changed and no longer within specification . An important point of this study is to knowing the rate of change of mechanical properties , especially strength so that it can be given the appropriate safety factors in the use of steel reinforced concrete structure. Concrete reinforcing steel bent structure with nine variations of the bending angle starting from the angle ( α ) of 20o , 40o , 60o , 80o , 100o , 120o , 140o , 160o , and 180o. The maximum value of the yield strength and tensile strength in the range of maximum bending process is 662.9607 and 704.0271 MPa in bending angle of 160 degrees and 100 degrees.
In the present study, two topics are mainly discussed, which are hull form design and then continued with performance analysis in ice condition and open water. For the hull form design the objective parameter are considered as follows; stem and the stern angles, upper and lower fore bulbous angles, entrance angles, and spreading angles. All those angles are investigated for both full loaded and ballast condition in ahead and astern. Special concern is needed for stern part due to existing propeller effect on ice breaking performance. The hull form is firstly investigated without installation of propeller to avoid the effect of pressure from propeller and then continued by installation of propeller to find the optimum propeller design and propeller immersion. Research in ice condition is compromised with open water. The optimum hull form, propeller design and propeller immersion is when the hull form gives better performance for both open water and ice condition.
This paper discusses about the implementation of a single microphone that is moving in linear track to substitute some channels of linear microphone array and a static microphone as a reference in beamforming method of sound source localization. The single microphone moves at constant velocity from a reference point. All recorded data from the moving and the reference microphone are split into several data represent each discrete microphone position. By this method, the sound localization system is modified from single microphone into artificial linear microphone array. Time delay for each artificial linear microphone is obtained by cross-correlation function between signal from moving microphone and signal from reference microphone. Time Domain beamforming method is performed by the delay-and-sum algorithm for stationary microphone. It is found that the methods can predict the direction of sound source. The shorter track and higher microphone speed can reduce the possibility of aliasing at high frequency sound. However, if the microphone moves closer to the sound source at higher speed, the possibility distortion of angle estimation increase caused by the Doppler effect. Furthermore, implementation of cross-correlation in beamforming can minimize the effect of random noise to predict the sound source direction.
This paper presents the experimental performance study to observe the effect of changes in the cooling load of the combined air conditioning and water heating system with trombone coil type as dummy condenser using heat wasted from split type air conditioner. Effects of the following parameters to the system performance were examined: compressor power test chamber, test chamber temperature, condenser temperature, hot water temperature and Coefficient of Performance (COP). The results showed that the bigger the cooling load is given in the test chamber, the bigger the heat absorbed in the evaporator, so the higher the temperature of the hot water in a tank. COP increased with increasing of cooling loads. It was concluded that by combined air conditioning and water heating system so that space cooling and water heating can take place simultaneously, and the energy performance can be raised considerably.
Hydroxyapatite is bioceramic s that widely used in the medical world especially for bone implant and cell culture . Hydroxyapatite was synthesized by low temperature hydrothermal method which sea shells as derived CaO and (NH 4) 2HPO 4 with Ca/P ratio of 0.67, 1.67, 2.67 were heated at 70°C, 80°C, 90°C and stirred at 300 rpm. The obtained paste was dried and then the powder calcined in the temperature range of 700°C - 1000°C. In order to study the morphology and structural characteristics, XRD and SEM were used to estimate the particle size of the powder. FTIR was used to identify organic or inorganic chemicals for estimating the number of components of an unknown mixture . The crystal diameter of hydroxyapatite increased with Ca/P ratio and reaction temperature. Majority hydroxyapatite phase was obtained at Ca/P ratio of 2.67 and 90°C reaction temperature.
