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Tapping screw fabricates the female thread due to plastic deformation during screw rotation. Since the tapping screw skips the preliminary fabrication of female thread, it is widely used for the tightening in the fields of such as electric parts and car parts. However, there is a few theoretical studies for its self-tapping process and loosening proof. In this paper, we have investigated the mechanism of tapping torque and shape of female thread using three-dimensional finite element analysis. In addition to the plastic flow caused by the friction force due to the rotation of male thread, the plastic flow at the top of male thread separated by the up and down directions occurs. That contact at thread top mostly contributes the torque of self-tapping. Also, plastic flow along the lower surface of frank thread separated by the outside and inside radial directions creates the characteristic shape of female thread. The analysis results well reproduce the tapping torque and the shape of female thread. We also investigate the loosening proofs due to shear loading both for tapping screw and normal screw using there-dimensional finite element analysis. The shape of female screw obtained by self-tapping analysis is incorporated into the analysis model. It is found that the loosening proof of the tapping screw is superior to that of normal screw since contact at the top of thread in the lower part of tapping bolt inhibits the thread slip.

For lower limb amputees, trans-femoral prostheses play an important role not only in regaining the gait ability of amputees, but also daily life activities. In recent years, the use of robotic technology has led to the development of robotic prostheses that provide better safety and comfortness in practicing normal walking. However, since daily activities other than walking rely heavily on the function of the sound leg, it is important not to put excessive burden on the sound leg in a mid-back posture and sit-to-stand motion. Therefore, in this study, in order to reduce the burden on the sound leg while using a prosthesis, we developed a new robotic prosthesis that maintains flexion posture at arbitrary knee angle in circumstances where the burden on the sound leg increases during daily life. Moreover, we proposed a model of daily activities based on finite state machine that represents not only walking, but also all daily activities such as sit-to-stand motion. Finally, we conducted experiments by a user of trans-femoral prosthesis and showed the effectiveness of maintaining flexion posture.

The authors previously developed an intermediate evaluation index for transfer characteristics of the structural system of the completed vehicle to enhance the sound quality of combustion noise. Based on the results, a method was developed to obtain an index for the power unit similar to the above intermediate evaluation index by a shaker test on a stationary power plant. It was found that this shaker test and transfer characteristics evaluation method can approximately estimate the frequency band in which the structural system amplifies half-order components of the combustion noise related to sound-quality deterioration without conducting an actual engine operation test. [ABSTRACT FROM AUTHOR]

Plating is a quite important technology used in a variety of sectors such as industrial products and decorative accessories. It is a special processing technology that handles various chemical substances and consists of long serial processes, plating is likely to encounter quality problems. Therefore, it is necessary to realize a method to maintain and manage plating process and evaluate the quality of plated products. The purpose of this study is the state recognition in the plating process and the quantitative evaluation of the quality of the processed surface using hyperspectral data for electroless nickel plating. The hyperspectral data is a combination of two-dimensional spatial information and spectral information with high wavelength resolution. Actual process recognition system with a hyperspectral camera was constructed to obtain and analyze the hyperspectral data of both the plating solution and the processed surface based on multivariate analysis. The non-contact and high-speed monitoring method could be realized to estimate phosphorous acid concentration which causes deterioration of plating solution. Furthermore, the quantitative evaluation of plating surface with newly defined parameters was proposed, and the monitoring results confirmed the validity of the proposed method.

In this paper, two-phase flow and ion transportation in an alkaline water electrolysis are discussed with three-dimensional coupling numerical simulation to reveal the influence of a bubble in the alkaline water electrolysis on the cell efficiency to achieve high-efficiency energy conversion of electrical energy to hydrogen energy. Two-phase flow numerical simulation model is not a void ratio model that is mainly used in previous studies, but is a direct simulation model with Lattices Kinetic Scheme that enables microscale flow simulation. Moreover, the concentration distribution is calculated with Maxwell equation and Nernst-Planks equation, and is fully coupled to the three-dimensional two-phase flow. The numerical simulations are conducted for w/o bubble condition and w/ bubble condition with varying applied current density to evaluate the influence of a bubble at various operating conditions. The results show that the bubble in the electrolyte induces mixing flow between a bubble and an electrode, and the concentration of potassium hydroxide (KOH) around the anode is increased. This increase of concentration increases the conductivity of the electrolyte and suppresses the overpotential in the electrolyte. Moreover, the anodic activation overpotential is also suppressed by the increased concentration on the anode. These overvoltage suppressions become much more prominent at high current density operating condition of the cell. The mixing with the bubble changes the concentration around the bubble. However, concentration distant from the bubble also changes and suppresses the overpotential with the change in electrical field.

In Japan, the number of people who have difficulty walking has been increasing with the rise in the aging population and that of people with physical disabilities. Individuals with athetosis-type cerebral palsy must use electric wheelchairs due to abnormal walking. However, since they have problems with fine motor control, including the occurrence of involuntary movements and difficulty maintaining posture, they have difficulty intentionally controlling their hand movements. Therefore, they cannot operate a joystick, even if they desire to use electric wheelchairs, and there are risks of accidents. In this study, by considering the arch structure of hand, we developed a new joystick grip that enables the suppression of involuntary movement. We evaluated our proposed grip by comparing running stability with a conventional grip, and demonstrated the effectiveness of proposed method.

The purpose of this study was to identify risk factors for throwing shoulder injury. 50 junior high school baseball players were included in the study. Data were collected on baseline information, limb mobility, muscle tightness, and the development of throwing shoulder injury. 1 year after the baseline measurements, the same measurements were taken again, and the subjects were divided into 2 groups according to whether or not they had developed throwing shoulder injury. All data were compared between groups by t-test or Mann-Whitney's U test. The variables with p<0.25 for between-group comparison were used as explanatory variables, and risk factors for throwing shoulder injury were analyzed by logistic regression analysis. 47 patients were included in the analysis, 14 of whom were in the throwing shoulder injury development group. The group with impaired shoulder had significantly restricted non-throwing side HBD (p=0.007), which was a risk factor for impaired shoulder (Odds ratio: 1.201, 95% CI: 1.058-1.374). Tightness of the rectus femoris muscle of the non-throwing lower extremity was found to be a risk factor for the development of throwing shoulder injury. [ABSTRACT FROM AUTHOR]

This paper introduces a resonance avoidance method for a 2-degrees-of-freedom (DOF) controlled maglev motor using d-axis current. The rotor of the 2-DOF controlled maglev motor has a disk shape, and the rotor radial motion is actively controlled. However, the axial and tilting motions are passively suspended, and hence, the significant rotor vibration is caused during rotation. To avoid the axial and tilting resonances, the motor d-axis current that regulates the strength of the magnetic field is provided for changing the axial and tilting stiffnesses, and hence, resonance points can be avoided during rotation. The axial and tilting stiffnesses with and without d-axis current were calculated by finite element method (FEM), and the rotor resonances were estimated. The rotor vibration was measured using a test machine with and without d-axis current, and the rotor vibrations in the axial and tilting directions were successfully reduced. The experimental results have verified the effectiveness of the proposed resonance avoidance method.

The purpose of this study to investigate the incidence and the location of injuries in throwing athletes. Collegiate and professional throwing athletes were given a questionnaire pertaining to their injury histories. In throwing athletes, the most common injury location was the lower back, with the exception of javelin throwers, who had the most injuries to the elbow joint. Low back injuries were the most common in throwing athletes, and elbow joint injuries were significantly more common in javelin throwers than in other throwers. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine the relative growth of muscle thickness in the lateral abdominal muscle groups of junior high school students as well as the differences in growth patterns between the three individual muscles. The subjects were 191 junior high school students from a local club team and the right external oblique; EO, internal oblique; IO and transversus abdominis; TrA muscle thicknesses were measured using an ultrasound imaging device. The height and these parameters were plotted on a logarithmic graph to obtain the allometric equation y = bxa. EO and IO were represented by three-phase straight lines with two inflection points, EO's allometry coefficients being 2.58,1.56, and 2.76, and the inflection points being 142.0 cm and 171.3 cm. IO's allometry coefficients were 0.82, 2.05, and 4.55, and its inflection points were 157.4 cm and 170.4 cm. TrA was depicted as two-phase straight lines with allometry coefficients of -1.53 and 1.56, with the inflection point of 145.3 cm. This suggests that TrA which has a stabilizing effect on the trunk, grows early. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine the accuracy of lumbosacral angle using MRI and an in¬clinometer, and to examine predictive regression of these two methods. Seventy adolescent boys experienced MR imaging of the lumbar region and lumbosacral alignment measurement using an inclinometer. Sacral slope was calculated as the angle between the top of the sacrum and the horizontal line. The lumbosacral angle was defined as the angle between the lumbosacral joint and the horizontal axis. Statistical analysis was performed using linear regression analysis to determine whether sacral slope can be predicted by the lumbosacral angle, and Bland-Altman method was used to evaluate the agreement between the two measurement methods. The fixed error cal¬culated as the difference between the sacral slope by MRI and the lumbosacral angle by inclinometer was 10.06 ± 3.29° (95%CI: 9.27-10.84), with small proportional and random errors. The regression equation was y=0.85x + 13.49. Although the results of this study indicated that the inclinometer underestimated the lumbosacral angle, if fixed error is taken into account, the measurement by inclinometer may be useful in predicting the lumbosacral angle in adolescent athletes. [ABSTRACT FROM AUTHOR]

This report describes the results of meteorological observations at Syowa Station from February 1st, 2003 to January 31st, 2004, and at Dome Fuji Station from February 1st, 2003 to January 20th, 2004, carried out by the Meteorological Observation Team of the 44th Japanese Antarctic Research Expedition (JARE-44). The observation methods, instruments and statistical methods used by the JARE-44 were almost the same as those used by the JARE-43 observation team. Remarkable weather phenomena observed during the period of JARE-44 are as follows.1) Annual mean surface temperature in 2003 at Syowa Station was-9.0℃, which was the second highest value in the historical record of Syowa Station. The number of snow days in 2003 at Syowa Station was 233 days, which set a record at Syowa Station.2) The amount of total ozone over Syowa Station became lower than or equal to 220 m atm-cm in mid-August, and was close to the minimum levels from September to October. The monthly means of total ozone in June and September at Syowa Station were the lowest values since the beginning of monitoring. The ozone hole in 2003 appeared earlier than usual. The annual maximum in the ozone mass deficiency and the ozone hole area were the second largest and the largest, respectively.3) The mean surface temperature in the wintering period (Feb., 2003-Jan., 2004) at Dome Fuji Station was-53.8℃; the lowest temperature was-79.6℃ observed on July 23rd.

Water driven stage is developed as a linear stage of the ultra-precision machine tool, especially, that is intentionally designed for the machining of small parts in size, such as optical mirrors and lenses. The water driven stage is mainly composed of a body of the stage and a table. The table is supported by water hydrostatic bearings and is driven by water hydraulic cylinder. Speed of the stage, determining the feed rate of the diamond turning, can be controlled by the flow rate into the water hydraulic cylinder. The paper deals with speed control of the stage. Mathematical models of the water driven stage and the proportional flow control valve are derived in order to design feedback control system. Performances of the designed feedback control system are verified via experiments and simulations. It is then verified that the steady state error is less than 0.5%. Step responses of the control system with a step input of the external load acting on the table are also tested, showing validity of the designed control system.