Human and robot allocation method for hybrid assembly systems

Manufacturing companies today need to increase both changeability and efficiency of production systems in order to strengthen their competitiveness. Hybrid assembly systems have evolved as solutions to counter this issue. In this system, humans and robots cooperate to perform assembly tasks; the system has the advantage of maximizing robot efficiency and human flexibility. This paper proposes a method for planning human and robot allocation in hybrid assembly systems. The method enables us to select the initial human and robot allocation, that minimizes the expected total production cost including robot investment and labor cost taking into consideration possible scenarios of future changes in product models and production volumes.     

Generation and control of electrolyte cathode atmospheric glow discharge using miniature gas flow

Stable electrolyte cathode atmospheric DC glow microdischarges were generated by using a miniature helium gas flow from a nozzle electrode in air. We developed two schemes to control the temporal evolution of the discharge and the interaction between the discharge column and the ambient air. The vaporization of electrolyte solutions takes place and affects the discharge characteristics. This takes time from the start of the discharge. Therefore, the discharge was controlled by applying pulse‐modulated DC voltages. If the voltage was dropped down to zero before the vaporization, the gas discharge developed without the ionization of the solution components. A helium gas discharge without air developed when the nozzle electrode was placed in a glass capillary. This was confirmed by examining the change in pH of the solution, which usually decreased owing to the generation of nitrogen oxides in the discharge in air. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 178(4): 8–15, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21222     

Reconfiguration management of remanufactured products for responding to varied user needs

In the face of worsening environmental problems, the manufacturing industry is required to reduce resource consumption and environmental loads during product life cycles while responding to diversified user needs without cost increases. In this paper, we propose a reconfiguration method to remanufacture a variety of products using modules extracted from returned products of multiple generations for responding to varied user needs. With this method, we can maximize the sales amount of remanufactured products, which meet the performance requirements of each user group. We demonstrate the effectiveness of the method by applying it to photocopiers.     

Oxidation behavior of (Ti1 − xAlx)N films perpared by r.f. reactive sputtering

(Ti, Al)N films have drawn much attention as alternatives for TiN coatings, which are oxidized easily in air above 500 °C. We have investigated the effect of Al content on the oxidation resistance of (Ti_{1 − x}Al_x)N films prepared by r.f. reactive sputtering.(Ti_{1 − x}Al_xN films (O ≤ x ≤ 0.55) were deposited onto fused quartz substrates by r.f. reactive sputtering. Composite targets with five kinds of Al-to-Ti area ratio were used. The sputtering gas was Ar (purity, 5 N) and N₂ (5 N). The flow rate of Ar and N₂ gas was kept constant at 0.8 and 1.2 sccm, respectively, resulting in a sputtering pressure of 0.4 Pa. The r.f. power was 300 W for all experiments. Substrates were not intentionally heated during deposition. The deposited films (thickness, 300 nm) were annealed in air at 600 900 °C and then subjected to X-ray diffractometer and Auger depth profiling.The as-deposited (Ti_{1 − x}Al_x)N films had the same crystal structure as TiN (NaCl type). Al atoms seemed to substitute for Ti in lattice sites. The preferential orientation of the films changed with the Al content of the film, x. Oxide layers of the films grew during annealing and became thicker as the annealing temperature increased. The thickness of the oxide layer grown on the film surface decreased with increasing Al content in the film. For high Al content films an Al-rich oxide layer was grown on the surface, which seemed to prevent further oxidation. All of the films, however, were oxidized by 900 °C annealing, even if the Al content was increased up to 0.55.     

Angiogenesis in pituitary adenomas

Angiogenesis, which is the formation of new blood vessels from preexisting capillaries, plays an important role in tumor growth and metastasis. In this review, the focus is on angiogenesis in pituitary adenomas. Angiogenesis of pituitary adenomas has been assessed by studying tumor microvessel density using specific immunohistochemical markers to clarify the relationship between angiogenesis and tumor behavior. Unlike other organs, pituitary adenomas have significantly lower vascular densities as compared to nontumorous adenohypophysis, suggesting that the lack of significant angiogenesis may play a role in the slow pace of pituitary tumor growth and rarity of metastases. In addition, the relationship between microvessel density and various factors in pituitary adenomas is reviewed, including tumor types, age and sex, invasiveness, malignancy, several proliferative markers (MIB-1 or Ki-67). However, further studies will be needed, since many studies have reached opposite conclusions. Angiogenesis is a complex multistep process and several factors are found to be involved in each step of neovascularization, such as vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and various other cytokines. VEGF and bFGF (or FGF-2), which are the most potent angiogenesis inducers among them, have been studied by immunohistochemistry, in situ hybridization, or in vitro studies in normal or adenomatous pituitaries and these results are also discussed in this review.     

Oral sustained delivery of paracetamol from in situ gelling xyloglucan formulations

The purpose of this study was to evaluate the potential of a xyloglucan formulation with in situ gelling properties for the oral sustained delivery of paracetamol. Gelation of dilute aqueous solutions of the polysaccharide xyloglucan occurred in rabbit and rat stomachs as the orally administered chilled solutions attained body temperature. In vitro studies demonstrated diffusion-controlled release of paracetamol from the gels over a period of 6 hr. The bioavailabilities of paracetamol from the xyloglucan gels formed in situ in the stomachs of rabbits after oral administration of the liquid formulations were similar to that of a commercially available suspension containing an identical dose of paracetamol.     

Assignments of optically pumped CH3OD laser lines

Fifteen laser lines from CH₃OD pumped by a CO₂ laser are assigned to specific rotational energy transitions. These assignments have been obtained from the approximation that, except for one constant, the molecular constants in the excited CO stretching state are same as those in the ground state.     

Nonaqueous titrimetric analysis of sulfuric and alkylbenzene sulfonic acids in detergent intermediates

A single differential nonaqueous titration method is presented for the analysis of sulfuric and alkylbenzene sulfonic acids in a detergent intermediate material. The organic and sulfuric acids in the sample were quantitatively titrated potentiometrically with standard cyclohexylamine solution. With certain specified sample compositions, approximate sulfuric acid determinations may be made without sample weighing or the use of standardized titrant. The titration is based upon the ratio of the first and second end points of the differential titration curve. Because of its simplicity, the latter method adaption is especially useful for routine control type analyses.     

In situ gelling pectin formulations for oral sustained delivery of paracetamol

The purpose of this study was to evaluate the potential of a pectin formulation with in situ gelling properties for the oral sustained delivery of paracetamol (acetaminophen). The formulations consisted of dilute aqueous solutions (1% to 2% w/v) of low methoxy pectin containing calcium ions in complexed form, which on release in the acidic environment of the stomach caused gelation of the pectin. In vitro studies demonstrated diffusion-controlled release of paracetamol from the gels over a period of 6 h. A bioavailability of approximately 96% of that of a paracetamol solution could be achieved from gels containing an identical dose of drug formed in situ in the stomachs of rats, with appreciably lower peak plasma levels and a sustained release of drug over a period of at least 6 h.     

Uniaxial tensile and shear deformation tests of gold-tin eutectic solder film

This paper describes a novel experimental technique for measuring mechanical properties of gold-tin (Au-Sn) eutectic solder film used for soldering package in microelectromechanical systems (MEMS). Dual-source DC magnetron sputtering was employed to deposit Au-20 weight % (wt%) Sn film. The tensile test with in situ X-ray diffraction (XRD) measurement evaluates the Young's modulus and Poisson's ratio at intermediate temperatures. The Young's modulus and Poisson's ratio at room temperature were found to be 51.3 GPa and 0.288, lower than bulk values. The Young's modulus decreased with increasing temperature, whereas the Poisson's ratio did not depend on temperature. The XRD tensile test also showed creep deformation behavior of Au-Sn film. We have developed a shear deformation test technique, which is performed by using Au-Sn film sandwiched by two single crystal silicon (Si) cantilever structures, to characterize the shear properties of the film. The shear moduli obtained from the shear deformation tests ranged from 11.5 to 13.3 GPa, about 38% lower than those from the XRD tensile tests. The measured shear strength from 12 to 17 MPa exhibited a temperature dependency. Information about the tensile and shear characteristics would likely to be of great use in designing Au-Sn soldering packages for MEMS.