Integrated in-process chatter monitoring and automatic suppression with adaptive pitch control in parallel turning

Simultaneous processes such as parallel turning or milling offer great opportunities for more efficient manufacturing because of their higher material removal rates. To maximize their advantages, chatter suppression technologies for simultaneous processes must be developed. In this study, we constructed an automatic chatter suppression system with optimal pitch control for sharedsurface parallel turning with rigid tools and a flexible workpiece, integrating in-process chatter monitoring based on the cutting force estimation. The pitch angle between two tools is tuned adaptively in a position control system in accordance with the chatter frequency at a certain spindle speed, in a similar manner as the design methodology for variable-pitch cutters. The cutting force is estimated without using an additional external sensor by employing a multi-encoder-based disturbance observer. In addition, the chatter frequency is measured during the process by performing a low-computational-load spectrum analysis at a certain frequency range, which makes it possible to calculate the power spectrum density in the control system of the machine tool. Thus, the constructed system for automatic chatter suppression does not require any additional equipment.The full text can be downloaded at https://link.springer.com/content/pdf/10.1007%2Fs40436-018-0222-0.pdf     

Caput epididymitis but not orchitis was induced by vasectomy in a murine model of experimental autoimmune orchitis

Immunization of mice with viable syngeneic testicular germ cells (TGC) alone can induce autoimmune responses against autoantigens of both round and elongating spermatids, resulting in the development of experimental autoimmune orchitis (EAO). Histological lesions in this EAO model without an adjuvant are characterized by lymphocytic infiltration into the testes, spermatogenic disturbance, and a complete lack of epididymitis. In this study, we investigated the effects of vasectomy (Vx) on TGC-induced EAO expecting that Vx augments the severity of testicular inflammation in A/J mice. The results showed that mice receiving Vx alone exhibited no significant inflammatory cell response in either the testes or epididymides, and mice receiving shamVx+TGC immunization had EAO with no epididymitis. In sharp contrast, no EAO was found in the testes of any mice receiving Vx+TGC immunization. Instead, caput epididymitis involving CD4+T cells, CD8+T cells, B cells, and macrophages were induced in them with striking elevation of the tissue levels of both IL6 and IL10 mRNA. Furthermore, serum autoantibodies induced by shamVx+TGC immunization were reactive with both round (immature) and elongating (mature) spermatids; however, those induced by Vx+TGC immunization were specific to acrosomes of mature spermatids and spermatozoa. These unexpected results indicate that Vx may induce the mode by which autoreactive lymphocytes gain access to TGC autoantigens in the epididymides, leading to autoimmune responses against the autoantigens of mature rather than immature spermatids.     

Observation of Si pattern sidewall using inclination atomic force microscope for evaluation of line edge roughness

Inclination atomic force microscope (AFM) imaging has been studied on the possibility to observe a pattern sidewall in contact mode or digital probing (step-in) mode for a line edge roughness (LER) or line width roughness (LWR). Analysis of the AFM tip bending and slipping indicates that it is serious problem to measure and control very fine patterns within an error of less than 1 nm in contact of the tip on the steep slop of the pattern, and it is very important directly to observe the sidewall at inclination angle. In experiments using pyramidal tip and steep Si pattern with about 90 degrees slop, it has demonstrated that the inclination angle is 35-40 degrees for faithful observation of the sidewall. We have observed the etched strip lines on the sidewall with a width of about 100 nm and a depth of about 6.4 nm. We have demonstrated that the inclination AFM is very useful for evaluation of the LER or LWR.     

Possible role of immunocompetent cells and the expression of heat shock protein-25 in the process of pulpal regeneration after tooth injury in rat molars

Recent studies have established that heat shock proteins (HSPs) potentially play a role in immunosurveillance. The purpose of the present study was to clarify the relationship between the chronological changes of immunocompetent cells and the expression of HSP-25 in the process of pulpal regeneration after tooth injury in rat molars by immunocytochemistry for HSP-25 and class II major histocompatibility complex (MHC) antigen. In untreated control teeth, intense HSP-25 immunoreactivity was found in the cell bodies of odontoblasts. Both cavity preparation and tooth replantation caused the degeneration of the odontoblast layer to result in the loss of HSP-25 immunoreactions in the suffered dental pulp at the early stages after tooth injury. Numerous class II MHC-positive cells appeared along the pulp-dentin border and extended their cell processes into the dentinal tubules at 12-24 h after cavity preparation and 3 days after tooth replantation. Newly differentiated odontoblast-like cells with HSP-25 immunoreactivity were arranged at the pulp-dentin border and the class II MHC-positive cells retreated towards the subodontoblastic layer by post-operative days 3-5 after tooth injury. Thus, the common cellular events occur during pulpal regeneration following two different experimental injuries. These findings indicate that the time course of changes in the expression of HSP-25 immunoreactivity reflects the degeneration/regeneration process of odontoblasts and that the temporal appearance of the class II MHC-positive cells at the pulp-dentin border suggests their participation in odontoblast differentiation as well as in initial defence reactions during the pulpal regeneration process.     

Novel fabrication method for long silicon microneedles with three‐dimensional sharp tips and complicated shank shapes by isotropic dry etching

This paper proposes a novel fabrication method for long solid microneedles made of silicon, which have a three‐dimensional sharp tip, by using isotropic dry etching. Since the fabrication is done in a direction parallel to the surface of the silicon substrate, there is no limit for the needle length. Also, the shank shape of this needle is freely designed three‐dimensionally by defining the mask on the silicon surface. For example, a jagged or harpoon shape is possible by using the proposed method, which may be effective for some medical applications. First, several three‐dimensional, complicated‐shaped needles with sharp tip angles were fabricated by changing the mask pattern. Second, a penetration experiment with them on an artificial skin was carried out, and easy penetration comparable with a conventional metal solid needle was confirmed. For an example of lancet application for diabetics, one of the needles was inserted into a human skin, and bleeding was confirmed. Copyright © 2007 Institute of Electrical Engineers of Japan© 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

A newly developed rotary-linear motion platform with a giant magnetostrictive actuator

Demands for machining and measuring three-dimensional geometries have recently increased in a variety of industries. In order to meet such demands, it is necessary to develop a compact versatile high performance spindle system. This paper presents a newly developed rotary motion platform combined with a linear motion mechanism driven by a giant magnetostrictive actuator. The developed platform can be characterized by a compact structure, a noncontact structure, and high accuracy. Performance evaluation results confirm that the developed platform provides precise linear motion during rotating.     

On the pressure drop and the velocity distribution in the cylindrical vortex chamber with two inlet pipes for the control of vortex flow

Vortex flow is applied to a cyclone dust collector, a vortex combustion chamber, and a vortex diode for vortex control. In order to apply the vortex flow to the industries, it is necessary to keep the stable flow condition and to estimate the response time of the transient flow process and also the intensity of the vortex flow. For control vortex flow, two types of vortex chamber with two inlet pipes were designed. One of them is to promote the vortex flow named as Co-Rotating Flow System and another one is to hinder the vortex flow named as Counter-Rotating Flow System. The pressure drops and the velocity distributions were measured for these vortex chambers. The estimation of the tangential velocity by the application of the angular momentum flux is compared with the measured velocity by a cylindrical Pitot-tube. The characteristics of the total pressure drop could be explained by introducing the circulation.