Fatigue strength evaluation for bolt-nut connections having slight pitch difference considering incomplete threads of nut

Proceedings of 4th International Conference on Fracture Fatigue and Wear, FFW 2015, Ghent University, Belgium, 27-28 August 2015The high strength bolts and nuts are widely used in various fields. In this study the effect of slight pitch difference is considered when the nut pitch is αμm larger than the bolt pitch. In the first place, the fatigue experiment is conducted with varying pitch difference. The results show that the fatigue life is extended to about 1.5 times by introducing the suitable pitch difference under the high stress amplitude. Next, the detail observation is performed on the fractured specimens including the fractured positions and the crack configurations. It is found that the fractured positions and the crack distributions vary depending on the pitch difference. Finally, to clarify the improvement mechanism of the fatigue strength, the finite element method is applied to calculate the stress amplitude and mean stress at each bolt threads, and the incomplete threads at the nut ends are also considered to obtain the accurate analytical results

Auricular Acupuncture at the “Shenmen” and “Point Zero” Points Induced Parasympathetic Activation

Purpose. Since auricular acupuncture is a diagnostic and treatment system based on normalizing the body’s dysfunction, auricular acupuncture has been applied for pain relief, relaxation, and so on. These techniques would modulate the autonomic nerve system, thereby inducing the above-mentioned effects. The aim was to see the effect of auricular acupuncture applied to the “Shenmen” and “Point Zero” points on the postoperative heart rate variability (HRV). Methods. Twenty-six patients who underwent hemicolectomy under general anesthesia were randomized into the control or the acupuncture group. After the operation and before emergence, the acupuncture group received auricular acupuncture. An electrocardiographic unit was placed for recording the autonomic nervous activities. Results. The low frequency (LF)/high frequency (HF) ratio of HRV increased () in the control, but the ratio in the acupuncture did not change. There were significant differences between the ratios of the two groups at 3 : 00, 4 : 00, and 5 : 00. HF of the acupuncture group tended to be higher. HFs of the acupuncture group were significantly higher than those of the control group at 3 : 00, 4 : 00, and 5 : 00. Conclusion. Auricular acupuncture kept the LF/HF ratio at lower levels and HF at higher levels during postoperative period in the patients who had undergone hemicolectomy

Azuki Bean Juice Lowers Serum Triglyceride Concentrations in Healthy Young Women

Effects of azuki bean juice supplementation, prescribed according to a Kanpo medicine regimen, on serum lipid concentrations were studied. Healthy young Japanese women were recruited and were randomly assigned to one of the three groups using a parallel-group design. Control (n = 10), azuki (n = 11) and Concentrated azuki (CA) (n = 12) juice groups consumed 150 g daily of the isocaloric assigned juice for one menstrual cycle with their usual diet. Triglyceride concentrations were decreased in the azuki juice group (p<0.05) and tended to be decreased in the CA juice group (p = 0.055). Triglyceride concentrations in the azuki and CA juice groups decreased by 0.170 mmol/liter (15.4%) and 0.159 mmol/liter (17.9%), respectively (p<0.05). The azuki and CA juice used in this study inhibited pancreatic lipase activity 29.2% and 56.9%, respectively, in vitro. Lipid peroxide changes, based on ANCOVA with the initial level and α-tocopherol changes as covariates, did not differ among the three groups. Serum low density lipoprotein-cholesterol and high density lipoprotein-cholesterol (HDL) cholesterol concentrations did not change. Thus, azuki bean juice intake, as a traditional Kampo prescription, might be beneficial for preventing hypertriglyceridemia

Effects of equivalent composition on superconducting properties of high-entropy REOBiS2_2 (RE = La, Ce, Pr, Nd, Sm, Gd) single crystals

Superconductors are influenced by high-entropy alloys (HEAs); these have been investigated in various functional materials. REOBiS$_2$ (RE = La, Ce, Pr, Nd, Sm, and Gd in different combinations) single crystals with HEAs at the RE-site were successfully grown using the flux method. The obtained crystals were plate-shaped (1 mm$^2$) with a well-developed c-plane. Ce was present in both trivalent (Ce$^{3+}$) and tetravalent (Ce$^{4+}$) electronic configurations; the concentration of Ce$^{4+}$ at the RE-site was approximately 10 at% in all single crystals. The single crystals showed superconducting transition temperature with zero resistivity within 1.2-4.2 K. The superconducting transition temperature, superconducting anisotropy, electronic specific heat coefficient, and Debye temperature of the crystals were not correlated with the mixed entropy at the RE-site. Except for the electronic specific heat coefficient, the variation of these parameters as a function of mixed entropy showed different trends for equivalent and non-equivalent RE element compositions. Thus, the configuration of RE elements influences the superconducting properties of REOBiS$_2$ single crystals, alluding to a method of modulating transition temperatures

Fatigue life improvement by slight pitch difference in bolt-nut connections

The bolt-nut connections are widely used in various fields. In this paper, a slight pitch difference is introduced between the bolt and nut in order to study the effect on the fatigue performance. Here, we consider that the nut pitch is a few microns larger than the bolt pitch. Fatigue experiments are conducted for three kinds of specimens with different levels of pitch differences. The obtained S-N curves show that the fatigue life is extended to about 1.5 times by introducing a suitable pitch difference. According to the detailed investigation on the fractured specimens, it is found that the fractured positions and the crack configuration are totally different depending on the pitch difference. The mechanism of the fatigue strength improvement is discussed in terms of the stress amplitude and average stress at each bolt thread