Rheo-optical studies on the deformation mechanism of semi-crystalline polymers. IX. Dynamic birefringence behaviour of a high-density polyethylene film having row nucleated crystalline texture of c-axis orientation

The dynamic birefringence behaviour of a high-density polyethylene film having a row-nucleated crystalline texture of cylindrites oriented along the machine direction of fabrication was investigated over frequency and temperature ranges covering the α mechanical dispersion of this material. The results are discussed in combination with the dynamic X-ray diffraction behaviour of the material so as to explore the structural origins of the α mechanical dispersion, not only for this particular material, but also for bulk-crystallized polyethylene having a spherulitic texture. Two deformation processes contribute to the α₁ mechanism, corresponding to the lower temperature relaxation process in the α mechanical dispersion; i.e. (i) a lamellar detwisting process involving the rotation of crystal grains within the crystal lamellae or of lamellar segments around the crystal b-axis or the lamellar axis, which predominates in the MD (machine direction) specimen, and (ii) lamellar shearing associated with the rotation of the crystal grains or the lamellar segments around the crystal a-axis, which is accentuated in the TD (transverse direction to fabrication) specimen. An additional deformation process, lamellar bending, is also observed in the MD specimen as being likely elastic in the dynamic response, and its contribution is found to be substantial, not to the α dispersion, but rather to the β dispersion of this material. The α₂ mechanism corresponding to the higher temperature relaxation process in the α mechanical dispersion is observed to be more pronounced in the TD than in the MD specimen. The apparent dynamic crystal lattice compliance shows a definite dispersion during activation of the α₂ mechanism, but a slight dispersion during activation the α₁ mechanism, suggesting that the α₂ mechanism must be related to an intracrystal relaxation process whereas the α₁ mechanism must be associated with an intercrystal relaxation process at their boundaries.     

Effects of classifier structures and training regimes on integrated segmentation and recognition of handwritten numeral strings

In integrated segmentation and recognition of character strings, the underlying classifier is trained to be resistant to noncharacters. We evaluate the performance of state-of-the-art pattern classifiers of this kind. First, we build a baseline numeral string recognition system with simple but effective presegmentation. The classification scores of the candidate patterns generated by presegmentation are combined to evaluate the segmentation paths and the optimal path is found using the beam search strategy. Three neural classifiers, two discriminative density models, and two support vector classifiers are evaluated. Each classifier has some variations depending on the training strategy: maximum likelihood, discriminative learning both with and without noncharacter samples. The string recognition performances are evaluated on the numeral string images of the NIST special database 19 and the zipcode images of the CEDAR CDROM-1. The results show that noncharacter training is crucial for neural classifiers and support vector classifiers, whereas, for the discriminative density models, the regularization of parameters is important. The string recognition results compare favorably to the best ones reported in the literature though we totally ignored the geometric context. The best results were obtained using a support vector classifier, but the neural classifiers and discriminative density models show better trade-off between accuracy and computational overhead.     

Experimental and numerical study on the relationship between creep crack growth properties and fracture mechanisms

Evaluation of creep crack growth properties taking microscopic aspects into account is effective for developing more accurate life prediction of structural components. The present study investigated the relationship between creep crack growth properties and microscopic fracture aspects for austenitic alloy 800H and 316 stainless steel. The growth rate of wedge-type intergranular and transgranular creep crack could be characterized by creep ductility. Creep damages formed ahead of the void-type crack tip accelerated the crack growth rate. Based on these experimental results, a three-dimensional finite element method (FEM) code, which simulates creep crack growth, has been developed. The effect of creep ductility on da/dt vs C* relations could be simulated based on the critical strain criteria. The diffusion of vacancies toward crack tip would accelerate the crack growth under creep conditions. The change of vacancy concentration during creep was computed for a three-dimensional compact-type (CT) specimen model by solving the diffusive equation under multiaxial stress field. The experimental results that crack growth was accelerated by creep damages formed ahead of the crack tip could be successfully simulated.     

Analysis of residual solvents in natural flavorings by headspace GC using the standard addition method

Headspace GC using the standard addition method has been developed for the simultaneous determination of organic solvents in natural flavorings. The procedure can be outlined as follows: an aliquot of the sample is transferred to a 10 mL vial. To each vial, a DMSO solution containing solvents at different concentrations is added as the standard solution. The vials are kept at 50 degrees C (for automatic injection) or 40 degrees C (for hand-operated injection) for 40 minutes. One mL of the vapor phase in each vial is injected into a gas chromatograph equipped with an Aquatic-2 column (0.25 mm i.d. x 60 m). To evaluate this method, we conducted a performance study in collaboration with 10 laboratories, using ginger oleoresin. We analyzed 6 solvents (methanol, 2-propanol, acetone, dichloromethane, hexane, and 1,1,2-trichloroethene) for which the maximum residue limits are established in Japan's Specifications and Standards for Food Additives. Methanol and acetone existed in the ginger oleoresin, so only the other that four kinds of solvents were added to it. Eight of the laboratories used automatic injection, while the remaining two used hand-operated injection. Statistical analyses were conducted on the data obtained from the 8 laboratories. Repeatability standard deviations (RSDr) ranged from 4.3 to 11.4%, and reproducibility standard deviations (RSDR) ranged from 8.4 to 19.0%.     

Effects of carp and tuna oils on 5-fluorouracil-induced antitumor activity and side effects in sarcoma 180-bearing mice

In this study, we examined the effects of fish oils on 5-fluorouracil (5-FU)-induced antitumor activity in mice. First, we examined the antitumor activity of the oral administration of two fish oils (carp oil and tuna oil) in sarcoma 180-bearing mice. Carp oil (0.2 and 0.4 mL/mouse) and tuna oil (0.2 and 0.4 mL/mouse) had no effects on tumor growth. Next, we examined the combined effects of 5-FU plus two fish oils (carp oil and tuna oil) on the antitumor activity and side effects compared to the effects of 5-FU alone (12.5 mg/kg/d). We found that carp oil (0.4 mL/mouse) or tuna oil (0.2 or 0.4 mL/mouse) enhanced the ability of 5-FU (12.5 mg/kg/d) to prevent tumor growth, without increasing side effects such as myelotoxicity and immunocompetent organ toxicity. Tuna oil (0.2 mL/mouse) slightly reduced body weight as compared to the effects of 5-FU alone and water alone (control). The area under the curve (AUC) (0–120 min) of blood 5-FU levels was reduced by the oral co-administration of 5-FU with carp oil or tuna oil. Apparent T _max was shortened by the oral co-administration of 5-FU with carp oil or tuna oil. On the other hand, AUC (0–4 h) of 5-FU incorporation into tumor RNA fraction was not affected by the oral co-administration of 5-FU with carp oil or tuna oil.     

Development of a high-performance laser-guided deep-hole boring tool:: Optimal determination of reference origin for precise guiding

A laser-guided deep-hole boring tool using piezoelectric actuators was developed to prevent hole deviation. To extend the depth of controllable boring further, the following were improved. The tool’s guiding error, caused by misalignment of the corner cube prism and the mirror in the optical head from the spindle axis, was eliminated using an adjustment jig that determined the reference origins of the two position-sensitive detectors (PSDs) precisely. A single-edge counter-boring head is used instead of the double-edge head used up to now. The former was thought to be better in attitude control than the latter. A new boring bar, which was lower in rigidity and better in controllability of tool attitude, was used. Experiments were conducted to examine the performance of the new tool in detail and to determine its practical application, using duralumin (A2017-T4) workpieces with a prebored 108-mm diameter hole. The experiments were performed with a rotating tool–stationary workpiece system. Rotational speed was 270 rpm and feed was 0.125 mm/rev. Tool diameter was 110 mm. As a result, controlled boring becomes possible up to a depth of 700 mm under the stated experimental conditions. 700 mm is the maximum machinable length of the machine tool. The tool can be put to practical use.     

Quantitative Evaluation of Bulk and Interface Microstructures in Al-3003 Alloy Builds Made by Very High Power Ultrasonic Additive Manufacturing

Ultrasonically consolidated 3003 aluminum alloy builds were prepared with constituent tapes by using a very high power ultrasonic additive manufacturing (UAM) process. Microstructures of interface and bulk regions were quantitatively characterized using the electron backscattered diffraction technique. The interface microstructure consists of equiaxed grains. The 〈111〉 crystallographic directions of these grains were aligned with the normal direction of the specimen, confirming a shear deformation mode at these regions. In addition, due to recrystallization, the density of low-angle grain boundaries also significantly decreased. In contrast, original elongated grains and partially recrystallized grains were observed in the bulk region of the tape. These elongated grains correspond to rolling texture components of face-centered-cubic materials. The preceding microstructure gradients are rationalized based on the accumulated thermomechanical cycles during processing.     

Microstructures and Thermoelectric Properties of Sintered Misfit-Layered Cobalt Oxide

Misfit-layered cobalt oxide Ca₃Co₄O₉ is considered to be a prospective material for thermoelectric conversion. The thermoelectric properties are anisotropic owing to its anisotropic crystal structure. The crystal has preferred thermoelectric properties along the a–b plane. Therefore, the thermoelectric properties are improved and controlled by the degree of orientation of the sintered sample. In the present work, Sr-doped misfit cobalt oxide Ca_2.7Sr_0.3Co₄O₉ was prepared by solid-phase reaction, followed by uniaxial compression molding and sintering at 1173 K. The Seebeck coefficient α, electrical resistivity ρ, and dimensionless figure of merit ZT were measured as a function of the compression pressure applied in the uniaxial molding. α, ρ, and ZT as functions of the degree of orientation and the relative density are experimentally clarified and explained by calculations using the compound model.     

Basic Study on Loss Factor Evaluation of Concentrated Winding Permanent Magnet Synchronous Motor

This paper describes the influence of pulse width modulation (PWM) inverter harmonic loss on concentrated winding interior permanent magnet synchronous motor characteristics by using finite element method (FEM) analysis and several measurements. In the measurements, the PWM inverter harmonic loss was evaluated by using a PWM inverter and a sinusoidal power supply. By using the FEM analysis, it was confirmed that the PWM inverter harmonic mainly caused an increase of eddy current losses in the magnetic steel sheet and the permanent magnet. The results indicate that higher inductance of the motor is effective in reducing the harmful effects of PWM inverter harmonics.     

Artificial RNA aptamer production by the marine bacterium Rhodovulum sulfidophilum: improvement of the aptamer yield using a mutated transcriptional promoter

Noncoding small RNAs and artificial RNA aptamers are now expected to be potential candidates for RNA therapeutic agents. We previously proposed a unique method for economical production of these RNAs using the marine phototrophic bacterium Rhodovulum sulfidophilum. This bacterium does not produce any ribonucleases but does produce extracellular nucleic acids in the culture medium in nature. Using this bacterium and an engineered plasmid containing the rrn promoter for the RNA expression, we developed a method for production of the streptavidin RNA aptamer in the culture medium. However, the yield of this RNA product in the culture medium by this method was not enough for practical use. In the present paper, we improved the yield of this product by modification of the -35 region of the rrn promoter so as to escape from the Fis protein control and the use of a new vector plasmid. Using this system, the extracellular RNA aptamer of approximately 200 ng and the total RNA aptamer (both extra- and intracellular form) of about 20 μg from 1 L culture were accomplished by constitutive expression of the gene.