Measurement and Estimation of High-Vacuum Effective Thermal Conductivity of Polyimide Foam in the Temperature Range from 160 K to 370 K for Outer Space Applications

Polyimide foam (PF) is a low-thermal conductivity and lightweight material with high resistances against heat, protons, and UV irradiation. A new thermal insulation composed of PFs and multiple aluminized films (PF–MLI) has potential to be used in outer space as an alternative to conventional multilayer insulation (MLI). As fundamental numerical data, the effective thermal conductivity of PF in wide ranges of density and temperature need to be determined. In the present study, thermal-conductivity measurements were performed by both the periodic heating method and the guarded hot-plate method in the temperature range from 160 K to 370 K and the density range from 6.67  \(\mathrm{kg} \cdot \mathrm{m}^{-3}\) to 242.63  \(\mathrm{kg}\cdot \mathrm{m}^{-3}\) . The experiments were carried out in a vacuum and under atmospheric pressure. For confirmation of the validity of the present guarded hot-plate apparatus under atmospheric pressure, the effective thermal conductivity of the lowest-density PF was measured with the aid of the heat flow meter apparatus calibrated by the standard reference material (NIST SRM 1450c) in the temperature range from 303 K to 323 K. In order to cross-check the present experimental results, the temperature and density dependences of the effective thermal conductivity of PF were estimated by means of the lattice Boltzmann method based on a dodecahedron inner microscopic complex structure model which reflects a real 3D X-ray CT image of PF.     

Transforming growth factor-beta inhibits interferon-gamma secretion by lymphokine-activated killer cells stimulated with tumor cells

The effect of transforming growth factor-beta (TGF-beta) secreted by glioblastoma (T98G) cells on the secretion of interferon-gamma (IFN-gamma) by lymphokine-activated killer (LAK) cells stimulated with tumor cells was investigated in cocultures of LAK and Daudi cells supplemented with T98G culture supernatant, T98G culture supernatant preincubated with anti-TGF-beta 1 and anti-TGF-beta 2 neutralizing antibodies, anti-TGF-beta 1 and anti-TGF-beta 2 antibodies, or natural human TGF-beta 1 or recombinant human TGF-beta 2. LAK cells were incubated with anti-TGF-beta 1 and anti-TGF-beta 2 antibodies, and with T98G cells of which the supernatant contained both active and latent forms of TGF-beta 1 and TGF-beta 2, with or without neutralizing antibodies. Addition of the supernatant from T98G cells to LAK/Daudi culture caused inhibition of IFN-gamma secretion by LAK cells. The inhibition was abolished by pretreatment of the supernatants with anti-TGF-beta antibodies. Addition of TGF-beta 1 and TGF-beta 2 to the LAK/Daudi culture inhibited IFN-gamma secretion by LAK cells in a dose-dependent manner. Addition of anti-TGF-beta antibodies to the LAK culture resulted in increased IFN-gamma secretion. T98G cells failed to stimulate LAK cells to secrete more IFN-gamma. Addition of anti-TGF-beta antibodies to the LAK-T98G culture resulted in increased IFN-gamma secretion by LAK cells. These results suggest that most malignant glioma cells which secrete high levels of TGF-beta can inhibit IFN-gamma secretion by LAK cells even after tumor cell stimulation.     

Recrystallization and precipitation behavior of low-activation V-Cr-Ti alloys after cold rolling

Recrystallization and precipitation behavior after cold working were investigated for three V-4Cr-4Ti alloys, NIFS-HEAT-1, NIFS-HEAT-2 and US 832665, which contain different levels of impurities. The decrease in hardness and the initiation of recrystallization against test temperature do not depend on the oxygen level. However, the rate of grain growth decreased with the increase in the impurity levels. Bimodal distribution of the precipitates was observed after annealing at 1273 K. The large precipitates were Ti-rich precipitates, and the small ones were composed mainly of Ti, C and O (Ti-C-O precipitates). The impurities were dissolved from Ti-C-O precipitates above 1273 K, and the level of impurities in the matrix increased and resulted in the increase in the hardness. Based on the results, the annealing temperature for V-4Cr-4Ti alloys is recommended not to exceed 1273 K for the purpose of maintaining good mechanical properties such as tensile and impact properties.     

Development of Nanoscale Temperature Measurement Technique Using Near-field Fluorescence

A nanoscale thermal system design, especially for the precise measurement of the temperature distribution in microfabricated devices using novel nanomaterials such as carbon nanotubes and fullerene has become increasingly important along with the development of nanotechnology. A new approach has been proposed toward an optical nanoscale temperature measurement method using near-field optics and fluorescence thermometry, namely, Fluor-NOTN (fluorescent near-field optics thermal nanoscopy). The topographic image and temperature dependence of a fluorescently modified sample, excited by near-field light, are simultaneously monitored. In this article, the temperature dependence of Cy3 fluorescent dye is verified near room temperature (298–308 K). A Cy3 mono-dispersed sample of a permalloy (Ni₈₁Fe₁₉) wire heater, 500 nm in width and 100 nm in thickness, is designed and fabricated. A localized temperature gradient of ΔT = 4 K within a submicron distance from the heater was successfully detected by near-field fluorescence with 100 nm spatial resolution.     

Pre-emptive analgesia from intravenous administration of opioid: no effect with pentazocine

The influence of timing of administration of preoperative pentazocine on pain and analgesic requirements after surgery was studied in 46 patients undergoing total abdominal hysterectomy. Twenty-three patients received thiamylal 5 mg.kg-1 on induction of anesthesia, followed by pentazocine 30 mg or 60 mg before surgical incision (group A). Twenty-three control patients received pentazocine 30 mg or 60 mg, 5 min after abdominal incision (group B). The visual analogue scales for pain 24 h after operation were 6.0 cm at 30 mg dose in group A or 5.3 cm at 60 mg dose in group A and 5.7 cm at 30 mg dose in group B or 4.7 cm at 60 mg dose in group B. There were no differences in the visual analogues scales. Pentazocine consumption in the first 24 h after surgery was 67.5 mg at 30 mg dose in group A or 52.5 mg at 60 mg dose in group A and 70.9 mg at 30 mg dose in group B or 51.8 mg at 60 mg dose in group B. We conclude that postoperative pentazocine consumption and pain scores are no different when pentazocine is given before or after skin incision for abdominal hysterectomy and that there is no clinically useful pre-emptive analgesic effect with these doses of pentazocine.     

The deformation of beams structured by thin walls

Nowadays our society demands the reuse of industrial products. Then we should not only re-investigate the materials of products but also originate a new design method of industrial products. We have investigated the cellular structure by using abandoned paper, because the cell's shape can be proposed arbitrarily by folding a paper. As examples, we have proposed the structure constructed by connecting many folded cells formed in a hexagonal cross area. This structure will have characteristics such as almost high rigidity, high stiffness, crushing stress, relative insensitivity to the overall loss of stability. To estimate the characteristics of these structures, we must analyze the deformation in loading. When the structure with thin walls formed by paper is loaded, the shape of deformation is different from that of the metal, wall swells and does not maintain its flatness. Therefore, we cannot apply the traditional theory of elasticity for the analysis. In this paper, we propose a new estimation method by analyzing the swelling.     

Analysis of the 300 MHz pmr spectrum of poly(2-vinyl thiophene)

Summary The 300 MHz pmr spectrum of poly(2-vinyl thiophene), poly-2-VT, is presented and analyzed. The aliphatic proton resonance of this polymer is very similar to that of polystyrene, but the aromatic proton resonance is rather well defined, especially that of protons in the 3-position of the thiophene ring. The resonance of such protons occurs as a three peak pattern that has been interpreted in terms of pentad stereosequences. Based on the assignments made in this paper, poly-2-VT prepared by free radical initiated polymerization seems to be atactic.     

Tool wear prediction and economics in machining stepped parts

For analysing economics of machining cylindrical stepped parts, tool life must be predicted. In this paper, tool life tests, to obtain tool life changing cutting speed before the tool reaches tool life criterion under a constant speed, are performed and the tool life is calculated. Using the results of the calculations machining economics of various forms of stepped parts for the constant spindle rpm method and the constant cutting speed method, are analysed.     

Vitamin E and coenzyme Q concentrations in the thyroid tissues of patients with various thyroid disorders

Chylous fistula complicates 1.1% of all radical neck dissections, and 2.4% of left-sided dissections. The standard treatment of established chylous leak in the reported cases is a pressure dressing applied to the lower neck. Here we present a case of chylous fistula, where conservative methods failed to cope with this complication. The additional application of a fibrin adhesive set was a successful modality of treatment.