Developments of Multi-wavelength Spectro-Polarimeter on the Domeless Solar Telescope at Hida Observatory

To obtain full Stokes spectra in multi-wavelength windows simultaneously, we developed a new spectro-polarimeter on the Domeless Solar Telescope at Hida Observatory. The new polarimeter consists of a 60 cm aperture vacuum telescope on an altazimuth mount, an image rotator, a high dispersion spectrograph, polarization modulator and analyzer composed of a continuously rotating waveplate with a retardation nearly constant around 127$^{circ}$ in 500 - 1100 nm and a polarizing beam splitter located closely behind the focus of the telescope, fast and large format CMOS cameras and an infrared camera. The slit spectrograph allows us to obtain spectra in as many wavelength windows as the number of cameras. We characterized the instrumental polarization of the entire system and established the polarization calibration procedure. The cross-talks among the Stokes Q,U and V are evaluated to be about 0.06% $sim$ 1.2% depending on the degree of the intrinsic polarizations. In a typical observing setup, a sensitivity of 0.03% can be achieved in 20 - 60 second for 500 nm - 1100 nm. The new polarimeter is expected to provide a powerful tool to diagnose the 3D magnetic field and other vector physical quantities in the solar atmosphere.Comment: 22 pages, 12 figures, accepted for publication in PASJ (Hida topical issue

Construction of Prestressed Concrete Pavement Slabs in Osaka City

This paper describes the prestressed concrete pavement slabs, 60 m and 40 m in length which were constructed in Osaka City in January of 1958. Prestressing steel was laid in both longitudinally and transversely in the 60 m slab, and diagonally with angles of intersection of about 60 deg. in the 40 m slab. The construction and testing of the pavement slabs are described in detail. The results prove the superior behavior of prestressed slabs, especially in their elastic recovery, and indicate that. such construction could be advantageously utilized in future pavement construction when it becomes economically comparable with other forms of construction

Studies on the Yield of Plastic Hinges in Concrete Beams

Experimental studies were carried out to investigate the yield of plastic hinges in reinforced and prestressed concrete beams. Eighty-eight simple beams and thirty-two two-span continuous beams were tested under static loading to failure and theoretical analysis was made as to the rotation capacity of plastic hinges and the redistribution of internal bending moments. The rotation capacities of plastic hinges were analysed using the reinforcement index q. To examine the yield of plastic hinges in continuous beams, the measured strengths of beams were compared with those calculated values based on the simple beam tests. Though a prestressed concrete beam does not show any definite yield phenomena, the plastic rotation can also be calculated just as in case of reinforced concrete beams. But the rotation capacities of the former are a good deal smaller than that of the latter. The yield of plastic hinges though partly incomplete, were recognized both in prestressed and reinforced concrete beams

Study on the Differential Shrinkage of Composite Prestressed Concrete Beam

This paper describes the results of experimental studies made on the effects of differential shrinkage of the composite beams having the flange or the upper half portion cast on the precast prestressed beam. The cast-in-place concrete was made with artificial lightweight aggregates. In all thirty beam specimens were fabricated and the variables involved in the specimens were : shape of cross-section, amount of shear connecter, ratio of shear span to beam depth, and age at casting slab. Differences of shrinkage and creep characteristics between the cast-in-place lightweight concrete and the precast normal concrete were measured by using the control specimens. The differential shrinkage set up internal stresses in the composite construction and its effects on the cracking moment and on the ultimate strength of the composite beams were investigated and compared with the theoretical analysis. It is concluded that the differential shrinkage has so profound an effect that it should be taken into consideration in design, especially when the slab concrete is placed at a later time

Plastic Flow of Reinforced Concrete

We present herein the theoretical analysis of plastic flow of reinforced concrete and the test results obtained during about fourty-six weeks of sustained loading on twenty-three reinforced concrete columns. Two conditions of reinforcement were investigated for the columns of same size. This research program was intended to examine the effects of the time of loading on the plastic flow of reinforced concrete. By the results obtained, we found that the Whitney's Law pertaining to the plastic flow of concrete can also be applied to the reinforced concrete when the ratio of reinforcement is comparatively low, but in. case of high percentage in the ratio of reinfocement, due consideration must be given

Strain Measurements of Prestressed Concrete Cylindrical Tank Walls

This paper presents the results of strain measurement on prestressed cylindrical concrete tank walls at the time of transferring of prestress. Freyssinet's method as well as Preload's method are employed to transfer prestress to the prestressed concrete tank walls. By means of Carlson type strainmeters embeded in the concrete, strains due to prestressing and bending moments accompanied by prestressing in the longitudinal direction are measured and compared with the theoretical values for each of the above described methods. The results obtained show that the prestresses applied meet fairly well the design requirements and the measured strains satisfactorily coincide with the theoretical values in the angular (tangential) direction. It is expected that comparatively large strains occur due to the circumferential prestressing, while the measured strains are approximately a half of the theoretical values