Integration of external and internal dosimetry in Switzerland

Individual monitoring regulations in Switzerland are based on the ICRP60 recommendations. The annual limit of 20 mSv for the effective dose applies to the sum of external and internal radiation. External radiation is monitored monthly or quarterly with TLD, DIS or CR-39 dosemeters by 10 approved external dosimetry services and reported as H(p)(10) and H(p)(0.07). Internal monitoring is done in two steps. At the workplace, simple screening measurements are done frequently in order to recognise a possible incorporation. If a nuclide dependent activity threshold is exceeded then one of the seven approved dosimetry services for internal radiation does an incorporation measurement to assess the committed effective dose E(50). The dosimetry services report all the measured or assessed dose values to the employer and to the National Dose Registry. The employer records the annually accumulated dose values into the individual dose certificate of the occupationally exposed person, both the external dose H(p)(10) and the internal dose E(50) as well as the total effective dose E = H(p)(10)+E(50). Based on the national dose registry an annual report on the dosimetry in Switzerland is published which contains the statistics for the total effective dose, as well as separate statistics for external and internal exposure.     

Neuartige Umbaukonzepte für einen 280 m hohen abgespannten Mast

New approaches to converting a 280 metres tall guyed mast. In the course of optimizing the antenna system of the long‐wave transmitting station EUROPE 1 extensive reconstruction and reinforcement of a guyed mast measuring 280 metres tall were necessary. Due to the planned reconstruction and the consequent greater strain loads on the lattice structure the corner legs of three sections had to be replaced. For this purpose a scaffold was put up and the mast was hoisted using a hydraulic lifting device. The scaffold was fixed to the mast using tube clamps to make it resistant to sliding and without any direct screw fittings being used. In this way the relevant corner legs in the bridged area were able to be dismantled and replaced by larger profiles. In addition, a new concept for insulation in accordance with the “fail‐safe” principle was realized. For that purpose a numerical simulation was undertaken to demonstrate the effects of the rupture of an insulator on the guy forces.     

Modeling gas diffusion into metals with a moving-boundary phase transformation

A fixed-grid, finite-difference model is developed to investigate the moving-boundary phase transformation that occurs during gas charging or discharging from finite specimens. The model is developed in a nondimensional form, and solutions are calculated for plane sheets, cylinders, and spheres. Numerical predictions are compared with existing analytical solutions, as well as experimental data for the β/α transformation of titanium induced by diffusion of oxygen from the surface of a plane sheet. Finally, a parametric study is performed to elucidate the effect of several input parameters on phase transformation kinetics, and simple empirical relations for the transformation time are developed based on this study.     

Cyclic martensitic transformations and damage evolution in shape memory zirconia: Single crystals vs polycrystals

In zirconia-based shape memory ceramics (SMCs), cracking during the martensitic transformation can be avoided in structures that reduce the relative presence of grain boundaries where high levels of transformation mismatch stress develop. This approach has been well established in single crystals, but only for sample sizes below about 5 microns. In this paper, we extend the strategy of eliminating grain boundaries to bulk specimen scales by fabricating mm-scale single crystal SMCs via cold crucible induction melting. For 1.5 and 2.0 mol% Y₂O₃-ZrO₂, we study the cyclic martensitic transformation of both single crystal and polycrystal structures. Whereas single crystals have very repeatable transformation behavior in terms of hysteresis and strain amplitude, polycrystals degrade dramatically as they accumulate cracking damage with repeated cycling. As the polycrystal evolves from a pellet to granular packing of loose single crystals/grains, the energy dissipation converges with that of the single-crystal structure, and the energy spent on cracking throughout that process is captured by calorimetry analysis. These results verify that grain boundaries play a key role in damage evolution during martensitic transformation and that microstructural control can extend the size-scale of viable single crystal or oligocrystal SMCs from the micro- to the millimeter scale.     

Time-resolved picosecond photocurrents in contacted carbon nanotubes

We introduce coplanar stripline circuits to resolve the ultrafast photocurrent dynamics of freely suspended carbon nanotubes (CNTs) in the time domain. By applying an on-chip pump-probe laser spectroscopy, we demonstrate that CNTs, contacted by metal electrodes, exhibit a picosecond photocurrent response. We find a combination of an optically induced ultrafast displacement current, transport of photogenerated charge carriers at the Fermi velocity to the electrodes, and interband charge-carrier recombination processes to dominate the ultrafast photocurrent of the CNTs.     

Impact of carboxymethyl cellulose (CMC) and microcrystalline cellulose (MCC) on functional characteristics of emulsified sausages

Inclusion of fibers, such as carboxymethyl cellulose (CMC) and microcrystalline cellulose (MCC), at the expense of fat or protein in meat batters could be used to produce healthier sausages while lowering production costs. To study the impact of CMC/MCC on structural/functional characteristics of emulsified sausages, standard-fat Lyoner-style sausages were formulated with CMC/MCC at concentrations of 0.3–2.0%. Methods of analysis included rheology, water binding capacity (WBC), texture measurements, and Confocal Laser Scanning Microscopy (CLSM). WBC, texture measurements, and rheology all indicated that addition of CMC (> 0.7%) led to destabilization of the batter, which upon heating could no longer be converted into a coherent protein network, a fact that was also revealed in CLSM images. In contrast, MCC was highly compatible with the matrix and improved firmness (1405–1651 N/100 g) with increasing concentration compared to control (1381 N/100 g) while keeping WBC (4.6–5.9%) with < 2% MCC at the level of the control (4.8%). Results were discussed in terms of molecular interactions of meat proteins with celluloses.     

Polarization mode dispersion in spun fibers with different linearbirefringence and spinning parameters

This paper shows how the initial linear birefringence determines the necessary spinning parameters to produce spun fiber with optimum differential group delay (DGD) and polarization mode dispersion (PMD) properties. DGD measurements are reported on two pairs of fibers, each pair having been fabricated from a particular fiber preform. The fiber pairs each consist of a sample of spun and unspun fiber. These measurements are then compared with theoretical simulations for each fiber to determine the required range of spinning parameters for a given initial linear birefringence. These results should help in optimizing the spinning parameters for producing high-performance spun fibers     

Porous titanium implant materials and their potential in orthopedic surgery

In orthopedic surgery bony defects remains a challenge. In generally autologous or heterologous bony transplants can be used. Main problem is the limited amount of bone and donor site morbidity. Nowadays excellent implants and scaffolds at low costs are necessary in respect to the financial problems in our health care system and the strong financial limitations in clinical medicine. Recently a biomimetic approach, in which a porous synthetic bone substitute with properties similar to these of trabecular bone has been developed (VITOFOAM?). Aim of our study was to investigate whether cp‐Ti or Ti6Al4V or stainless steel (316L) porous metal implants achieve material properties comparable to bone. Materials and Methods Three cp‐Ti, Ti6Al4V and stainless steel (316L) porous metal specimen each with a pore size of 150 to 600 μm have been tested in respect to determine the Young’s Modulus E (GPa), Compression Strength (MPa) and Porosity (%) under axial compression. Results Young’s Modulus of the cp‐ Ti samples was in the range of 1.2 to 2.8 GPa, for Ti6Al4V 2.3 to 4.1 GPa could be achieved. Compression Strength for cp‐ Ti and Ti6Al4V ranged from 30 to 65 MPa with porosity values ranged from 71 to 80 %. Discussion The highly porous nature of VITOFOAM? combined with the good biocompatibility of cp‐ Ti or Ti6Al4V and the mechanical properties make these materials ideal bone scaffolds. Trabecular bone shows pore sizes of 300–1500 μm, Young’s Modulus of 0.2–2 GPa and Compression Strength from 5–50 MPa. Porosity of spongious bone ranges from 30 to 95 %. These values are comparable to the values achieved with VITOFOAM?. Porous titanium foam with its osteoconductive properties may therefore be an ideal and cheap alternative. Implant costs can be lowered to 50 % for implants e.g. for intercorporal interbody fusion in spinal surgery. Actually further research is done to show the possibility in spinal surgery or loading technologies with Tricalciumphosphat, Hydroxylapatit, Antibiotics or Cytostatics.