Effect of residual stress on the strength of alumina-steel joint with Al-Si interlayer

The effect of residual stress on the strength of an alumina-steel joint with the Al-Si interlayer was studied. Alumina rods, 32 mm in diameter and 9 mm in length and steel pipes were diffusion bonded at 873 K and at a contact pressure of about 5 M Pa for 30 min in a vacuum of 24×10^–2Pa. The interlayer of aluminium sheet clad with Al-10% Si alloy on both sides was used. The tensile strength of the joints is influenced by the thickness of the interlayer or the intermetallic compound formed between the interlayer and the steel. The strength increases with increasing interlayer thickness and with decreasing intermetallic compound thickness. It is found that the residual stress measured by Sachs method is much lower than that by the elastic calculation. The stress decreases with increasing interlayer thickness. Increase in thickness of the aluminium core of the interlayer is effective in improving the joint strength. This improvement can be explained by considering the stress of the joint.     

A study on the adsorption of dialkyldimethyl ammonium chloride

A study was made on the structure, adsorption behavior toward fabrics and dependence upon particle size of an aqueous dispersion of di(hydrogenated tallow)dimethyl ammonium chloride (purified Arquad 2HT), the most widely used softener base. From the results of analyses by X-ray diffraction, differential scanning calorimetry (DSC) and electron microscopy, it was found that the dispersed phase of Arquad 2HT dispersion consisted of hydrated particles having a similar structure to that of the multilayered liposomes (or vesicles) of phospholipids and that these particles were adsorbed onto fabrics by softening treatment It was also found that finely dispersed particles showed better softening and antistatic performances in addition to a superior storage stability, due to their higher rate and uniformity of adsorption compared to roughly dispersed particles.     

Crosslinking structure of keratin: III. Rubberlike elasticity originating from non-uniform structures of the swollen hair and wool fibers

Hair and wool fibers treated with an 11 M LiBr solution containing N-ethylmaleimide showed typical rubberlike elasticity in a solution composed of equal volumes of 8 M LiBr and diethylene glycol monobutyl ether. Stress–strain relations of the swollen fibers were treated with a two-phase structural model: a mechanically stable phase of higher crosslinked domains and a rubbery phase with lower crosslink density. Stress–strain curves were analyzed by applying non-Gaussian chain statistics to the swollen keratin network, including microdomains, which act as reinforcing filler particles in rubber. Swollen hair showed about 2.3 times higher modulus than wool. It has been suggested that: (1) the difference in the modulus between the two keratins is attributable to the difference in the volume fraction of domains, and (2) the crosslink density of rubbery phase in hair is virtually identical to that in wool.     

Visualization analysis of side‐edge flow phenomena in different thickness/width rectangular cavities using a rotary runner exchange system

The authors developed a rotary runner exchange system which is able to instantaneously switch between flow resins of two colors before the gate and proposed a new visualization method which enables observation of the internal flow behavior. In this study, the authors confirmed that resins of the initial filling stage are stretched into a horn shape along both sides of the cavity. This side‐edge flow area found to distribute along both sides of the rectangular cavity, and the distribution state varied with the change in the aspect ratio between the cavity width and thickness. With square cross sections, the side‐edge flow area was confirmed to divide into four corners. The same flow behavior does not occur with circular cross sections. With rectangular cross sections, a solidified layer and a nonflow layer grow consistently from the cavity wall during the flow process. This causes the shape of the residual flow area around the center of the cross section to change during the flow process. As a result of flow history of regions, where shear flow selectively continues over a long time, a horn‐shaped side flow is thought to be formed near both sides of the cavity or its four corners. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

In-vitro heat-generating and apatite-forming abilities of PMMA bone cement containing TiO2 and Fe3O4

Poly (methyl methacrylate) (PMMA) bone cement is widely used as a filler for repairing bone defects. To improve the effectiveness of the treatment for bone defects caused by metastatic bone tumours, we propose the formulation of PMMA cement containing titania (TiO₂) and magnetite (Fe₃O₄) that offers high bone affinity, making the cement suitable for use in magnetic hyperthermia. The TiO₂ and Fe₃O₄ contents of the PMMA cement varied from 20 to 45 mass%. The various cement samples were evaluated for their apatite-forming ability and heat-generation characteristics. The samples containing TiO₂ in concentrations of 15 mass% or higher formed apatite on their surfaces within 14 days in a simulated body fluid. The heat-generation characteristics of the samples were evaluated by applying an alternating current (AC) magnetic field under the following conditions: |H| = 40 Oe and f = 600 kHz, or |H| = 100 Oe and f = 100 kHz. The surface temperatures of the samples containing 25 and 30 mass% Fe₃O₄ reached 42.3 and 44.8 °C, respectively, at |H| = 40 Oe and f = 600 kHz. During hyperthermia treatment, cancer cells die at temperatures higher than 42 °C, and the cement samples fabricated in this study could reach this temperature. However, since some degree of heat loss will occur in vivo, it is necessary to ensure that the temperature is higher than 42 °C by varying the AC magnetic field. Nevertheless, the fact that the samples containing Fe₃O₄ concentrations of 25 mass% or higher generated enough heat under the AC magnetic field makes them suitable for clinical use in hyperthermia. Thus, PMMA cement containing 15 mass% or more of TiO₂ and 25 mass% or more of Fe₃O₄ should be investigated as a bioactive bone cement with a strong hyperthermia effect.     

Research on constitutions and physiology of skin-development of traditional Chinese medicine for skin

Evaluation studies in the development of new types of cosmetics are divided into exploratory and confirmatory research. The exploratory evaluation aims to discover the unknown characteristics of tested products, whereas the confirmatory evaluation aims to examine the attainment of their designed quality. This report presents an evaluation method to achieve simultaneously the two objectives using the think-aloud method with the paired comparisons method. The results obtained for two foaming cleansers possessed both exploratory aspects and confirmatory ones, and were straightforward in demonstrating the features of the foaming cleansers, because the think-aloud method was not restricted by a complicated evaluation procedure. The method proposed from the discussions can be readily applied to the process of new product development.     

Whole-Body Motion Generation Integrating Operator's Intention and Robot's Autonomy in Controlling Humanoid Robots

This paper introduces a framework for whole-body motion generation integrating operator's control and robot's autonomous functions during online control of humanoid robots. Humanoid robots are biped machines that usually possess multiple degrees of freedom (DOF). The complexity of their structure and the difficulty in maintaining postural stability make the whole-body control of humanoid robots fundamentally different from fixed-base manipulators. Getting hints from human conscious and subconscious motion generations, the authors propose a method of generating whole-body motions that integrates the operator's command input and the robot's autonomous functions. Instead of giving commands to all the joints all the time, the operator selects only the necessary points of the humanoid robot's body for manipulation. This paper first explains the concept of the system and the framework for integrating operator's command and autonomous functions in whole-body motion generation. Using the framework, autonomous functions were constructed for maintaining postural stability constraint while satisfying the desired trajectory of operation points, including the feet, while interacting with the environment. Finally, this paper reports on the implementation of the proposed method to teleoperate two 30-DOF humanoid robots, HRP-1S and HRP-2, by using only two 3-DOF joysticks. Experiments teleoperating the two robots are reported to verify the effectiveness of the proposed method.     

Direct Inhibition of SARS-CoV-2 Spike Protein by Peracetic Acid

Peracetic acid (PAA) disinfectants are effective against a wide range of pathogenic microorganisms, including bacteria, fungi, and viruses. Several studies have shown the efficacy of PAA against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); however, its efficacy in SARS-CoV-2 variants and the molecular mechanism of action of PAA against SARS-CoV-2 have not been investigated. SARS-CoV-2 infection depends on the recognition and binding of the cell receptor angiotensin-converting enzyme 2 (ACE2) via the receptor-binding domain (RBD) of the spike protein. Here, we demonstrated that PAA effectively suppressed pseudotyped virus infection in the Wuhan type and variants, including Delta and Omicron. Similarly, PAA reduced the authentic viral load of SARS-CoV-2. Computational analysis suggested that the hydroxyl radicals produced by PAA cleave the disulfide bridges in the RBD. Additionally, the PAA treatment decreased the abundance of the Wuhan- and variant-type spike proteins. Enzyme-linked immunosorbent assay showed direct inhibition of RBD-ACE2 interactions by PAA. In conclusion, the PAA treatment suppressed SARS-CoV-2 infection, which was dependent on the inhibition of the interaction between the spike RBD and ACE2 by inducing spike protein destabilization. Our findings provide evidence of a potent disinfection strategy against SARS-CoV-2.     

A FLUOROMETRIC ASSAY FOR PROTEINASE A IN BEER AND ITS APPLICATION FOR THE INVESTIGATION OF ENZYMATIC EFFECTS ON FOAM STABILITY

A previously developed fluorometric assay using synthetic substrate, Succinyl-Arg-Pro-Phe-His-Leu-Leu-Val-Tyr-4-methylcoumaryl-7-amide, for yeast proteinase A (PrA) was modified for the accurate and quick determination for the activity in unpasteurized beer. Employing simple HPLC for the determination of 7-amino-4-methylcoumarine (AMC), a final degradation product on this assay, the activity of PrA in beer was measured without the interference of the fluorogenic and photosensitive substance present in beer. The assay for common unpasteurized beers was completed within 5 hours without any concentration procedure. Its linearity and reproducibility were satisfactory for quantitative purposes. Using a purified PrA from brewer's yeast, the effect of the PrA activity on foam stability during storage was furthermore clarified. The exclusive effect of PrA on foam stability was also demonstrated by proteinase inhibitor test.