Erprobungsmethodik für zyklisch überelastisch beanspruchte Bauteile unter Torsion – Bauschinger‐Kenngrößen für 54SiCr6

Power transmission contains several torsion‐stressed parts. Especially shafts and springs are numerous considered. Helical springs as a special type of springs are mainly stressed by torsion load. During operation the spring's load is basically elastic. In some cases, like overload or machine disaster, the load exceeds the spring's yield stress. For a single event the deformations can be calculated easily by using flow charts. However in other cases the spring will be stressed several times with alternating plastic load. Therefore the calculation will not be as easy as in the single load case. Especially the hardening and softening mechanisms have major influence on material behavior. For high strength steel this material behavior is not fully investigated right now. Present article shows a way how to investigate several important Bauschinger parameters based on plastic torsion load for the high strength steel 54SiCr6. Finally it can be shown that 54SiCr6 is influenced by the Bauschinger effect. On the other hand the needed material characteristic can be investigated by the shown methodology. Based on the identified data, analytical and numerical calculation of alternating plastic torsion load can be done.     

Thermochemical Treatment--Technologies for Recovery and Utilisation of Materials

The arc furnace technology is an ideally suited process for the treatment of hazardous and problematic waste. The operation conditions of the arc furnace can be adapted for optimal transformation of the waste material input into raw materials and usable products. The process can significantly reduce the impact of contaminated wastes and industrial residues, and enable material conversion and separation. Thus, the products of the process have various applications. The capability of the process is illustrated with three examples, the treatment of bottom ash and filter ash from waste incineration plants, of stainless steel slags and of chromium containing residues from the refractory industry.     

Diffractive optical isolator made of high-efficiency dielectric gratings only

The working principle of an optical isolator made of two corrugated dielectric gratings is introduced. One grating acts as a polarizer, and the other acts as a quarter-wave plate used in conical incidence converting linearly polarized light into circularly polarized light. Global maxima of diffraction efficiency for surface-corrugated gratings with binary, sinusoidal, and pyramidal ridge shapes with dependence on the material index are identified. Regarding technological feasibility for use in the visible wavelength range, high-frequency gratings with a binary shape were realized. With these gratings, an extinction ratio of more than 40 dB for the polarizer is theoretically possible, and more than 20 dB was experimentally achieved. A good correlation between theoretically calculated efficiencies and birefringences based on rigorous methods and the experimental results is demonstrated.     

Polarization multiplexing of diffractive elements with metal-stripe grating pixels

Diffractive elements with polarization multiplexing for the visible spectral region are demonstrated. The polarization-multiplexing property of the element is based on the polarization-dependent transmission characteristics of metal-stripe subwavelength period gratings. The proper dimensions of these gratings are estimated by rigorous calculations. The principle of polarization multiplexing by use of metal-stripe subwavelength period gratings is described for a diffractive element that has a binary amplitude transmission per polarization channel and is demonstrated by experimental results.     

Optimized single-braided cable shields

Approximate formulas for the coupling parameters of cables with single-braided shields are presented. The derivation of the formulas is based on a qualitative analysis of the coupling mechanisms; these qualitative approaches have been verified and adjusted to reality by measuring many different braids. Assuming that the shields are grounded or open ended, the approximation formulas yield the high-frequency-optimizing equation, which permits the design of optimized single-braided shields     

Highly efficient transmission gratings in fused silica for chirped-pulse amplification systems

We report on highly efficient transmission gratings in fused silica with a grating period of 800 nm generated by electron-beam lithography. At a wavelength of 1060 nm, 95% diffraction efficiency is achieved under Littrow conditions. The damage threshold, extremely enhanced compared with conventional gold-coated diffraction gratings, makes these gratings the key elements in high average power (>100 W) femtosecond fiber chirped-pulse amplification systems.     

PA26, a novel target of the p53 tumor suppressor and member of the GADD family of DNA damage and growth arrest inducible genes

We report the cystathionine-beta synthase (CBS) gene expression pattern during early human embryogenesis (3 to 6 weeks post conception) by in situ hybridization and in fetal and adult tissue by Northern Blot analysis. Probes were chosen to recognize either the common sequence to all known CBS mRNAs or the sequences of two different major exons 1 issued of we have previously identified. We demonstrate by in situ hybridization that CBS is continuously expressed from the earliest stages studied (22 days post conception) during embryogenesis in the tissues of developing embryos which will after birth present clinical abnormalities in homocystinuria patients. It is expressed at an especially high level in the neural and cardiac systems until the liver primordium appears. In embryonic central nervous system, the whole neural tube and primary brain vesicles are labeled. Secondary brain vesicles labeling are dependent on the neuroepithelium differentiation. The ventricular layer of the rhombencephalon, cranial nerve nuclei and then after cerebellar cortex derived from rhombencephalon ventricular layer are strongly labeled. Thalamus and other derivatives of the diencephalon plate, the neuroblastic layer of the retina, lens and dorsal root ganglia are labeled. After 35 days post conception, CBS mRNAs was detected in endocardial cells and in cells derived from the neural crest of the heart and in particular developing mesodermic regions such as the primitive hepatocytes of the liver, mesonephros vesicles, various endocrine glands and developing bones. We could not detect tissue specificity of different probes at this embryonic stage. Northern blot analysis consistently detected mRNA species in fetal 25 weeks post conception brain, liver and kidney. The common cDNA probe revealed the 2.5 and 3.7 kb mRNA species from brain, liver and kidney. The exon 1b probe detected only the 2.5 kb mRNA and the exon 1c probe the 3.7 kb mRNA in these three tissues. In adult tissue, the 1b probe detected only the 2.5 kb mRNA and the 1c probe only the 3.7 kb mRNA in the liver.     

Measuring the coupling parameters of shielded cables

Methods for measuring the coupling parameters of shielded cables, transfer impedance, and transfer admittance are presented. In addition to a theoretical analysis, a simple easy-to-use low-cost measuring setup is shown. This setup permits the determination of modulus and phase of the coupling parameters. New measuring methods for the direct determination of the so-called optimizing factors, presented in an earlier paper (see ibid., vol.34, no.2, p.39-46, 1992) are also discussed. These methods are suitable for shielded cables and shielded cable harnesses as well     

Designing multiplane computer-generated holograms with consideration of the pixel shape and the illumination wave

The majority of image-generating computer-generated holograms (CGHs) are calculated on a discrete numerical grid, whose spacing is defined by the desired pixel size. For single-plane CGHs the influence of the pixel shape and the illumination wave on the actual output distribution is minor and can be treated separately from the numerical calculation. We show that in the case of multiplane CGHs this influence is much more severe. We introduce a new method that takes the pixel shape into account during the design and derive conditions to retain an illumination-wave-independent behavior.