The Strength of Metals under Combined Alternating Bending and Torsion

Fatigue tests under combined bending and torsion were carried out for several ferreous and nonferreous metals with a testing machine specially designed. As the results of tests, strength of metals under combined alternating bending and torsion were expressed by a simple relation, using fatigue strength of each metals under simple bending and torsion. And some considerations about fatigue fracture were made

The Strength of Metals under Combined Alternating Bending and Torsion with Phase Difference

A new fatigue testing machine capable of making experiments under combined alternating bending and torsion with any phase difference has been devised and proved to be satisfactory in operation by the authors. From the test results obtained by experiments carried out on some metals with the machine, the effect of phase difference on the strength of the metals under combined bending and torsion has been made clear

Studies on Fatigue of Mild Steel by a Corrosion Method

The fatigued zone in mild steel can be detected by a corrosion method as well as when yielded parts are shown as a strain figure. By the corrosion method, the authors have studied the appearances of the fatigued zone and fatigue crack in each specimen at progressive stages of fatigue. Consideration has also been made of the mechanism of fatigue failure with specimens having a smooth surface and having various notches

A New Criterion for the Strength of Metals under Combined Alternating Stresses

Matsumura's theory of malleable materials, stating that “the elastic failure occurs in malleable materials when the maximum shear stress reaches a definite value depending on shear strain energy” is fairly well applicable to results of experiments, so far as the material is ductile; but the theory is not applicable to brittle materials. Extending Matsumura's theory to all materials, ductile and brittle, the authors propose now a new criterion and applying it to the case of fatigue, they think that “the fatigue failure occurs in ductile materials when the greatest maximum shear stress induced by combined repeated stresses reaches a definite value depending on shear strain energy at the instant, and that the fatigue occurs in brittle materials when the greatest maximum principal stress induced by the combined repeated stresses reaches a definite value depending also on shear strain energy at the instant.”From this new criterion on fatigue, they derive the conditions of fatigue failure under the combination of various stresses. Comparing the results of calculation with those of experiments, it is established that the new criterion is fairly well applicable to results of experiments in every case

Effect of fish density on biological production in aquaponics combining lettuce hydroponics and loach aquaculture for controlled ecological life support systems in space

There is a need to develop production technology that effectively uses limited water and other resources to create a stable food supply in space. Aquaponics, which combine hydroponics and aquaculture, is expected to be an efficient system for producing crops and animal proteins. This system sustains the reuse of water and balances nutrient elements between both cultures using dissolved elements in fish excrement for plant growth. To evaluate the effect of fish density on biological production and nitrogen usage efficiency in aquaponics combining lettuce hydroponics and loach aquaculture, we investigated the growth performance of lettuce plants and loach fish. We focused on the balance of nutrient elements, especially nitrogen flow in the system. As a result, we found that lettuce grew in aquaponics with a half-strength standard solution with an optimal combination of the number of plants and fish as well as hydroponics with a standard solution. Increasing the density of loach fish and lettuce plants can increase the total biological production of fish and plants. However, it will be important to control both fish and plant densities to increase nitrogen recovery in aquaponics with a high fish density

Estimation of Arterial Viscosity Based on an Oscillometric Method and Its Application in Evaluating the Vascular Endothelial Function

This paper proposes an algorithm for estimating the arterial viscosity using cuff pressures and pulse waves measured by an automatic oscillometric sphygmomanometer. A change in the arterial viscosity during the enclosed-zone flow-mediated dilation test is calculated as an index for evaluating the vascular endothelial function %η. In all, 43 individuals participated in this study. After the index %η was calculated, the accuracy of the index %η in distinguishing healthy subjects and subjects at a high risk of arteriosclerosis was tested via a receiving operating characteristic (ROC) analysis. The calculated %η for the healthy participants and those at a high risk of arteriosclerosis was 13.4 ± 55.1% and −32.7 ± 34.0% (mean ± S.D.), respectively. The area under the ROC curve was 0.77. Thus, it was concluded that the proposed method can be used to evaluate the vascular endothelial function.This research was partly supported by the Transportation Technology Development Promotion Competitive Funding Program from Ministry of Land, Infrastructure, Transport and Tourism, and the Center of Innovation Program from Japan Science and Technology Agency

Seven Different Glucose-6-phosphate Dehydrogenase Variants Including a New Variant Distributed in Lam Dong Province in Southern Vietnam.

We conducted a survey for glucose-6-phosphate dehydrogenase (G6PD) deficiency using blood samples from male outpatients of a local hospital in southern Vietnam. Most of the samples were from the Kinh (88.9%), the largest ethnic group in Vietnam, with a small number (11.1%) coming from the K'Ho, Chauma, Nung, and Tay minorities. We detected 25 G6PD-deficient cases among 1,104 samples (2.3%), and read the open reading frame of G6PD. A novel mutation (352T>C) predicting an aminoacid change of 118Tyr>His was found in a 1-year-old Kinh boy. His G6PD activity was estimated to be less than 10% residual activity, although he did not show chronic hemolytic anemia. Thus, we categorized this variant as Class II and named it G6PD Bao Loc. In the Kinh population, G6PD Viangchan (871G>A, 1311C>T, intron 11 nt93T>C), one of the most common variants in continental Southeast Asian populations, was the highest (6/19), followed by variants originating from the Chinese such as G6PD Canton (1376G>T) (5/19), G6PD Kaiping (1388G>A) (3/19), G6PD Gaohe (95A>G) (1/19), and G6PD Quing Yuan (392G>T) (1/19). In addition, G6PD Union (1360C>T) (2/19), which originated from the Oceania, was also detected. These findings suggest that the Kinh people are derived from various ancestries from continental Southeast Asia, China, and Oceania. In contrast, all of the 5 deficient cases in the K'Ho population were G6PD Viangchan, suggesting that they were very close to Southeast Asian populations such as the Khmer in Cambodia and the Lao in Laos. It is interesting that G6PD Mahidol (487G>A), another common variant in continental Southeast Asian populations in Myanmar, Thailand, and Malaysia, has not been detected from the Vietnamese

Incidence and mutation analysis of glucose-6-phosphate dehydrogenase deficiency in eastern indonesian populations

We conducted a field survey of glucose-6-phosphate dehydrogenese (G6PD) deficiency in the eastern Indonesian islands, and analyzed G6PD variants molecularly. The incidence of G6PD deficiency in 5 ethnic groups (Manggarai, Bajawa, Nage-Keo, Larantuka, and Palue) on the Flores and Palue Islands was lower than that of another native group, Sikka, or a nonnative group, Riung. Molecular analysis of G6PD variants indicated that 19 cases in Sikka had a frequency distribution of G6PD variants similar to those in our previous studies, while 8 cases in Riung had a different frequency distribution of G6PD variants. On the other hand, from field surveys in another 8 ethnic groups (Timorese, Sumbanese, Savunese, Kendari, Buton, Muna, Minahasa, and Sangirese) on the islands of West Timor, Sumba, Sulawesi, Muna and Bangka, a total of 49 deficient cases were detected. Thirty-nine of these 49 cases had G6PD Vanua Lava (383T＞C) of Melanesian origin. In our previous studies, many cases of G6PD Vanua Lava were found on other eastern Indonesian islands. Taken together, these findings may indicate that G6PD Vanua Lava is the most common variant in eastern Indonesian populations, except for Sikka

Quantitative Evaluation of Pain during Electrocutaneous Stimulation using a Log-Linearized Peripheral Arterial Viscoelastic Model

In clinical practice, subjective pain evaluations, e.g., the visual analogue scale and the numeric rating scale, are generally employed, but these are limited in terms of their ability to detect inaccurate reports, and are unsuitable for use in anesthetized patients or those with dementia. We focused on the peripheral sympathetic nerve activity that responds to pain, and propose a method for evaluating pain sensation, including intensity, sharpness, and dullness, using the arterial stiffness index. In the experiment, electrocardiogram, blood pressure, and photoplethysmograms were obtained, and an arterial viscoelastic model was applied to estimate arterial stiffness. The relationships among the stiffness index, self-reported pain sensation, and electrocutaneous stimuli were examined and modelled. The relationship between the stiffness index and pain sensation could be modelled using a sigmoid function with high determination coefficients, where R2 ≥ 0.88, p < 0.01 for intensity, R2 ≥ 0.89, p < 0.01 for sharpness, and R2 ≥ 0.84, p < 0.01 for dullness when the stimuli could appropriately evoke dull pain.This work was supported by the Center of Innovation Program from Japan Science and Technology Agency.Supplementary information accompanies this paper at https://doi.org/10.1038/s41598-018-21223-1