Low-Alloy High-Strength Steels

IT is significant that this symposium on alloy steels is being held in the year 1956 which marks the centenary of the birth of tonnage steel. It was exactly a hundred years ago that Henry Bessemer heralded it new era by making it possible to produce steel for the first time in commercial tonnages. The largest proportion of steel made and rolled today finds its way into, structural appli-cations such as the building of bridges, transport cars, etc. Therefore structural steel occupies a promin-ent place in the eyes of the metallurgist and the engineer. Although the manufacture of Bessemer steel was well established within a few years of its discovery, the general use of steel in building bridges and other struc-tural uses had to wait for several years. As late as 1877, a Board of Trade Regulation in England prohibited the use of mild steel in bridges. The Firth of Forth Bridge built during 1 2380-1 8 90 used for the first time steel in large quantities. The earliest use of mild steel for bridges in U.S.A. was in the Eads Bridge over the 'Mississippi river. Since then the use of mild steel for bridges has become almost universal

Dolomite as a flux for High-Alumina Blast Furnace Slags

BLAST FURNACE operators at Jamshedpur have to face a peculiar problem arising out of the high concentration of it alumina in the slag. The normal analyses are 37.3-37.8% CaO, 3.4-3.9% MgO,30.4-31.5% SiO2, 26.2-27.0% Al2O3, 0.69-0.78% FeO and 0.69-0.82% S. The actual level, i.e. 26 to 28% is much higher than that common elsewhere and brings into force a series of adverse effects. Briefly, these consist of the greater viscosity of the alumina slags, greater tendency towards silicon reduction, and less efficient desulphurisation. As a result, it becomes rather difficult consistently to produce low-sulphur hot metal without exceeding the silicon level normally specified for basic iron

On the Possibility of Using Mn4N as a Neutron Polarizer

Abstract. Manganese nitride, Mn4N has been investigated by means of unpolarized as well as polarized neutron diffraction technique. It was found that both (100) and (110) reflections of this compound could produce almost 100% polarized, monochromatic neutrons. Furthermore, the two reflections provide opposite senses of polarization. While (100) reflects neutrons with spins aligned opposite to the magnetization, (110) reflection provides neutrons with spins parallel to the magnetization. This would offer possibility of producing polarized, monochromatic neutrons of either state of polarization by switching from one reflection to the other, without the use of electronic flipping devices. Sari. Nitrida mangan, Mn4N telah diteliti dengan teknik difraksi neutron tak-terpolarisasi maupun terpolarisasi. Ternyata kedua refleksi, (100) dan (110), dapat menghasilkan hampir 100% neutron terpolarisasi serta monokromatik. Lebih lanjut diketahui bahwa kedua refleksi tersebut menghasilkan polarisasi yang berlawanan arah. Refleksi (100) hanya memantulkan neutron dengan polarisasi yang berlawanan arah dengan magnetisasi, sedangkan refleksi (110) menghasilkan neutron dengan polarisasi searah dengan magnetisasi. Hal ini membuka kemungkinan untuk memproduksi neutron monokromatik dengan salah satu keadaan polarisasi, dengan cara berpindah dari suatu refleksi ke refleksi lainnya tanpa menggunakan alat elektronik

Inelastic Neutron scattering in CeSi_{2-x}Ga_x ferromagnetic Kondo lattice compounds

Inelastic neutron scattering investigation on ferromagnetic Kondo lattice compounds belonging to CeSi_{2-x}Ga_{x}, x = 0.7, 1.0 and 1.3, system is reported. The thermal evolution of the quasielastic response shows that the Kondo interactions dominate over the RKKY interactions with increase in Ga concentration from 0.7 to 1.3. This is related to the increase in k-f hybridization with increasing Ga concentration. The high energy response indicates the ground state to be split by crystal field in all three compounds. Using the experimental results we have calculated the crystal field parameters in all three compounds studied here.Comment: 12 Pages Revtex, 2 eps figures

Reduction of light output of plastic scintillator tiles during irradiation at cold temperatures and in low-oxygen environments

The advent of the silicon photomultiplier has allowed the development of highly segmented calorimeters using plastic scintillator as the active media, with photodetectors embedded in the calorimeter, in dimples in the plastic. To reduce the photodetector's dark current and radiation damage, the high granularity calorimeter designed for the high luminosity upgrade of the CMS detector at CERN's Large Hadron Collider will be operated at a temperature of about -30$^\circ$C. Due to flammability considerations, a low oxygen environment is being considered. However, the radiation damage to the plastic scintillator during irradiation in this operating environment needs to be considered. In this paper, we present measurements of the relative decrease of light output during irradiation of small plastic scintillator tiles read out by silicon photomultipliers. The irradiations were performed using a $^{60}\mathrm{Co}$ source both to produce the tiles' light and as a source of ionizing irradiation at dose rates of 0.3, 1.3, and $1.6\,$Gy/hr, temperatures of -30, -15, -5, and 0$^\circ$C, and with several different oxygen concentrations in the surrounding atmosphere. The effect of the material used to wrap the tile was also studied. Substantial temporary damage, which annealed when the sample was warmed, was seen during the low-temperature irradiations, regardless of the oxygen concentration and wrapping material. The relative light loss was largest with 3M$^{\tiny \textrm{TM}}$ Enhanced Specular Reflector Film wrapping and smallest with no wrapping, although due to the substantially higher light yield with wrapping, the final light output is largest with wrapping. The light loss was less at warmer temperatures. Damage with $3\%$ oxygen was similar to that in standard atmosphere. Evidence of a plateau in the radical density was seen for the 0$^\circ$C data

Oct4 Is Crucial for Transdifferentiation of Hepatocytes to Biliary Epithelial Cells in an in Vitro Organoid Culture Model

BACKGROUND: Hepatocyte to biliary transdifferentiation has been documented in various models of bile duct injury. In this process, mature hepatocytes transform into mature biliary epithelial cells by acquiring biliary phenotypic markers. Several signaling pathways including PI3 kinase, Notch, Hes1, Sox9, and Hippo are shown to be involved in the process. However, if Oct4 is involved in hepatocyte to biliary transdifferentiation is unknown. METHODS: We investigated the role of Oct4 in hepatocyte to biliary transdifferentiation utilizing an in vitro organoid culture system as a model of transdifferentiation. Oct4 was inhibited using adenovirus containing Oct4 shRNA. Hepatocyte specific HNF-4α and biliary specific HNF-1β & CK19 expression were assessed to gauge the extent of transdifferentiation. RESULTS: Oct4 was induced during hepatocyte to biliary transdifferentiation. Oct4 inhibition significantly downregulated the appearance of biliary cells from hepatocytes. This was accompanied by a significant downregulation of signaling pathways including Notch, Sox9, and Hippo. CONCLUSION: Our findings suggest that Oct4 is crucial for hepatocyte to biliary transdifferentiation and maturation and that it acts upstream of Notch, Sox9, and Hippo signaling in this model. This finding identifies new signaling through Oct4 in plasticity between hepatocytes and biliary epithelial cells, which can be potentially utilized to identify new strategies in chronic biliary diseases

Non-spherical magnetic moment in MnAlGe

The magnetic structure factors of MnAlGe (space group P4/nmm) measured with polarised neutrons have been expressed in terms of the magnetic moment of the Mn atom (site symmetry tetrahedral with tetragonal distortion), the Bessel transforms 〈jn〉 of the Mn radial functions and the fractional occupancies of the moment density in the various crystal field orbitals. The measured structure factors were least-squares fitted with the theoretical expression involving 〈jn〉 appropriate to the Mn0, Mn+ and Mn2+ atoms. The best fit was got using Mn0 transforms, yielding 1.45μB as the Mn magnetic moment. The fractional occupancies of the moment density in the crystal field orbitals A1g, B1g Eg and B2g were obtained. This analysis shows the magnetic moment to be highly non-spherical with a large fractional occupancy (38%) in the A1g orbital directed along the tetragonal axis while the fractional occupancies of B1g and B2g are found to be 31% and 30% respectively. The fractional occupancy of the moment in the Eg orbital directed towards the Ge and Al atoms is very low (1%). The spatially averaged moment density of Mn in MnAlGe is more diffuse than that of Mn I and Mn II in isostructural Mn2Sb