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Pre-cast concrete products are sometimes manufactured in two cycles per day production with one mold for the purpose of productivity improvement. In such cases, to secure the early strength, which is required at demolding, it is necessary to increase the steam-curing temperature. However, when this is done, the issue of temperature-related cracking becomes a concern. In addition, self-compacting concrete to which ground-granulated blast-furnace slag has been added is increasingly being used in consideration of the environment surrounding a plant and the operating environment. Admixing with an expansive agent prevents cracking due to autogenous shrinkage. However, when an expansive agent is admixed with concrete, the possibility also exists that the high-temperature curing required for two cycles per day production may increase the likelihood of cracking. In this study, the cause of cracking of large-sized pre-cast concrete products with high amounts of expansive agent was investigated and the products of one cycle per day production compared to those of two cycles per day production. The results obtained indicate that, in contrast to one cycle per day production, high-temperature steam curing and early demolding in two cycles per day production promote thermal stress cracking. In addition, unexpected cracking can occur along the main reinforcement resulting from excessive expansion due to inappropriate curing of the expansive agent.

A portable type of 3D ultrasonic inspection system, named “Matrixeye”, was applied to the spot welds, in which a matrix-arrayed probe was used as a sensing unit, and the welding zone in the spot welds was visualised 3-dimensionally. The matrix-arrayed probe, in which 64 piezoelectric elements are embedded as 8 × 8 matrix arrangement, can acquire more than 4 000 ultrasonic echo data points due to their transmission and reception in 0.2 seconds. This system can synthesise 3-dimensional ultrasonic images by SAFT (Synthetic Aperture Focusing Technique) installed in the parallel signal processing board. This system can also inspect the weld quality of spot welds with additional data; e.g., an averaged diameter, area, major axis, minor axis, thickness, and indentation depth of the welded region. In addition, this system has an automatic measurement function, in which the measurement automatically starts by sensing the probe contact with the welding surface, and automatically stops by sensing the position and tilt of the probe within a setting level. The results measured by this system have good correlation with the weld size on the fracture faces and the tensile-shear strength in the destructive tests. It was shown from the evaluated performance of the system that the developed system is applicable to the inspection of spot welds.

We report a simple method to functionalize DNA with π-conjugated polymer, forming highly aligned and integrated arrays of π-conjugated polymer nanowires of a few nanometers diameter. π-conjugated polymer, polyphenazasiline, having alkylammonium salts on the N atom (PPhenaz-TMA), synthesized in this study can be directly attached to DNA, which can be organized along stretched and aligned DNA molecules on surfaces as a template. Furthermore, PPhenaz-TMA/DNA nanowires were stretched and aligned on surfaces, even when PPhenaz-TMA/DNA complexes formed in solutions. The resulting PPhenaz-TMA/DNA nanowires could be easily converted to oxidized states or metallic nanowires by using adequate oxidant or metal salts. The direct visualization of PPhenaz-TMA/DNA nanowires and its structural changes have been studied by atomic force microscopy and scanning near-field optical microscopy.

The results of tests of combustion toxicity, hygroscopicity, and adhesive strength for fire retardant-treated plywood are described. The plywood was prepared from veneers treated with diammonium phosphate and ammonium bromide, and from glue mixed with poly (ammonium phosphate). Furthermore, the plywood boards were coated with boric acid. High ammonium phosphate and low or 0 ammonium bromide contents with the boric acid-coatings gave the greatest improvement in the combustion toxicity. Influence of almost all the treatments on the hygroscopicity was not significant. In all treatments the dry adhesive strength and the cyclic boil adhesive strength were slightly and considerably reduced, respectively.

In order to develop polycrystalline diamond compact (PDC) bits of about 8-1/2 in. in diameter which are able to drill geothermal wells, we have conducted the investigation with respect to the structure of a PDC cutter and rake angles, etc., by means of fundamental laboratory and field tests. New PDC core bits of 8-15/32 in. diameter were designed and manufactured based on the results of these tests. Then, field tests using them were carried out in geothermal wells at Hijiori in Yamagata prefecture, Hot Dry Rock project site in Japan, on September 1989 and October 1990. It became clear that the new PDC core bit can be sufficiently applied to the drilling of heterogeneous hot-hard rock formations from the tests.

Rock cutting, drilling and durability tests were conducted in order to obtain data to design polycrystalline diamond compact (PDC) bits for geothermal well drilling. Both conventional and new PDC bits with different rake angles were tested. The rock cutting tests revealed that cutting forces were minimized at −10 deg rake angle independent of rock type. In drilling and durability tests, a bit with backrake and siderake angles of −10 or −15 deg showed better performance concerning the penetration rate and the cutter strength. The new PDC bit exhibited better performance as compared to the conventional one, especially in hard rock drilling. Furthermore, a new PDC core bit (98.4 mm o. d., 66 mm i. d.) with eight cutters could be successfully applied to granite drilling equally as well as a bit with twelve cutters.

Surgery was undertaken on 32 chronic subdural hematomas in a series of 28 patients who had preoperatively undergone delayed contrast-enhanced computed tomography (DCECT). Timedensity curves on DCECT and iodine concentrations of subdural specimens revealed that chronic subdural hematomas, regardless of density, were significantly enhanced by the entrance of intravascular contrast medium into the interior of hematomas. The ingress of intravascular contrast medium into the interior of the hematomas was chemically proven and might result from a complex transcapillary shift.

The inhibitory action of pirenzepine on acid secretion of isolated guinea pig parietal cells was investigated by the aminopyrine method. Pirenzepine markedly inhibited acid secretion of isolated parietal cells induced by carbachol in a dose-dependent manner but showed no inhibition on acid secretion stimulated by histamine. These results may suggest a direct action of pirenzepine on muscarinic receptors in parietal cells.

In order to get the basic information of the substrates to be proposed for YBCO fimls to be adopted for future superconducting devices, energy dispersive X-ray ( EDX ) analysis and scanning electron microscopy ( SEM ) examinations have been performed for annealed YBCO relatively thin films pasted on various substrates and their cross sections. The results show the boundary layer of the intermediate products which consist of Ba compounds between the YBCO layer and the substrates (Al2O3, SrTiO3, Y 8% stabilized ZrO2).