Search

Laser-induced breakdown spectroscopy is applied successfully for plasma-wall interaction studies in several fusion devices and post-mortem analyses of plasma-facing materials. However, the quantitative as well as qualitative analysis of low hydrogen isotope contents in tungsten plasma-facing components is still challenging. A promising approach to increase the optical signal in laser-induced breakdown spectroscopy is to apply a second laser pulse to the laser-produced plasma. We present two setups for post mortem plasma-facing component analyses using different laser pulse properties and different excitation geometries. The enhancement factors and changes in spectral line shapes for double pulse compared to single pulse laser-induced breakdown spectroscopy are presented.

SummaryObjective: Male tortoises in captivity are often aggressive against other males or females, in particular during mating season related to hormonal influences (testosterone). Castration in males is the treatment of choice in many vertebrate species. A novel technique of minimal invasive castration is presented for Herman’s tortoises (Testudo hermanni).Material and methods: The procedure was performed in ten mature males. An endoscope (2.7 mm/30° angled) was inserted into a prefemoral incision on each side. The testicle was resected after ligation of the gubernaculum testis and the spermatic cord using hemoclips.Results: Each testicle could be removed in approximately 20 minutes. Complications like hemorrhage or damage of adjacent tissue did not occur and all animals recovered uneventfully.Conclusions and clinical relevance: Using the bilateral prefemoral entrance offers an alternative option for orchiectomy in Herman’s tortoises without dissection of the shell. Thus complications like hemorrhage or impaired wound healing followed by sequestration of the bone flap are prevented. Because of the anatomical settings and the risk of tissue damage and time consumption, a unilateral approach is not recommended. Fasting the animals is necessary due to the voluminous gastrointestinal tract of this herbivorous tortoise and emptying the urinary bladder provides more space for manipulations in the coelomic cavity and prevents clipping and cutting of adjacent organs. The magnification via the endoscope is beneficial for orientation in the coelomic cavity, which is formed by the extremely convex carapace. Without this equipment it is challenging to visualize the dorsocaudally located gonads through the relatively small incision and the inserted instruments might block the view at the surgical field. Administration of hemoclips achieved a good hemostasis and the testicles could be resected without major blood loss. The described technique is a gentle method for resection of the testicles in this species and can be adapted to other European tortoise species of equal size.

Cylinders of biomimetic (nanocrystalline) calcium phosphate were loaded with gentamicin by four different methods: 1) dip-coating, 2) impregnation followed by cold-isostatic pressing, 3) co-precipitation followed by cold-isostatic pressing, and 4) coating of co-precipitated particles with a biodegradable polymer PDLLA (poly-D,L-lactide), followed by uniaxial pressing. The release kinetics were studied in vitro over 10 days. The incorporation by methods 2), 3) and 4) showed a significantly higher long-term release of active gentamicin than dip-coating, although there was an initial burst during the first two days with all four methods. With method 4), there was an increase of the released gentamicin after 7 days, and the long-term release was the highest of these four methods. The results are of considerable interest for the preparation of biodegradable bone implants which are loaded with biologically active substances. Kontrollierte invitro Freisetzung von Gentamicin aus biomimetischem Calciumphosphat - Ein Vergleich von vier verschiedenen Methoden Zylinder aus biomimetischem (nanokristallinem) Calciumphosphat wurden nach vier verschiedenen Methoden mit Gentamicin beladen: 1) dip-coating, 2) Impragnierung mit nachfolgendem kalt-isostatischen Pressen, 3) Co-Fallung mit nachfolgendem kalt-isostatischen Pressen, und 4) Ummanteln der co-gefallten Partikel mit dem biodegradierbaren Polymer PDLLA (Poly-D,L-lactid) und anschliesenden uniaxialen Pressen. Die Freisetzung von Genatmicin wurde uber 10 Tage invitro verfolgt. Der Einschluss des Gentamicins bei den Methoden 2), 3), und 4) fuhrte zu einer signifikant hoheren Langzeit-Freisetzung von aktivem Gentamicin als dip-coating, obgleich bei allen vier Methoden ein anfanglicher Burst in den ersten zwei Tagen auftrat. Bei Methode 4) stieg die Freisetzung des Gentamicins nach 7 Tagen an, und die Langzeit-Freisetzung war die hochste von allen vier Methoden. Die Ergebnisse sind von erheblichem Interesse fur die Herstellung von biodegradierbaren Knochenimplantaten, die mit biologisch aktiven Substanzen beladen sind.

An overview of infrared spectroscopic applications—incoming product control, process control and final product control—shows the importance of this technique in the dairy industry. To ensure proper operation of the infrared techniques a monitoring system has to be introduced. These tasks can efficiently be performed within a network. Different kinds of networks will be discussed. The trend to move the infrared techniques into the production line is exemplary shown.

We investigate the structure of (Na 19 ) 2 -cluster timers via solution of the Kohn-Sham equations for a two-center jellium model. Results for the binding energy of the trimer as a function of the intercluster separation as well as the electronic correlation diagram of the (Na 19 ) 2 system are presented. In contrast to previous results, our calculations indicate that the barrier which separates a local minimum in the binting energy at an intercluster separation of about 15 a.u. from the absolute minimum, the unitd Na 38 cluster, is rather small

Publisher Summary Infrared (IR) spectroscopy plays a significant role in producing dairy products of high quality and consistency from farm to final product. Near-infrared (NIR) and mid-infrared (MIR) spectroscopy, are making new inroads into a range of applications in the dairy industry. These applications include process monitoring, determination of quality, geographical origin, and adulteration of dairy products in processes such as milk, milk powder, butter, and cheese production. NIR spectra and partial least squares (PLS) regression are employed to predict the total fat content of milk with a relative standard deviation of 2%. Fourier transform infrared (FTIR) spectroscopy can be used for the compositional analysis of sweetened condensed milk. Fat and total solids content can be predicted with accuracy in the order of ±0.09 and ±0.55 for fat and total solids respectively. MIR spectroscopy is employed to determine the fat and moisture content of butter samples. The MIR technique produces compositional values comparable to those obtained by conventional wet chemical methods. MIR spectroscopy can also be used for the quantitative analysis of edible trans fats in butter, and the characterization of butter, soybean oil, and lard. NIR spectroscopy can be employed to predict the solid fat content of milk fat extracted from butter during manufacture.

Elektromagnetische Strahlung kann auf vieWielfaltige Art mit der Materie wechselwirken. Infrarotstrahlung — elektromagnetische Strahlung im Wellenlangenbereich von 800 bis 200000 nm — kann unter bestimmten Voraussetzungen Schwingungen anregen. Im fernen Infrarot — 25000 bis 200000 nm — konnen dies z.B. in Festkorpern Gitterschwingungen oder in Gasen oder Flussigkeiten Molekulrotationen sein. Im mittleren Infrarot (MIR) — 2500 bis 25000 nm — werden Ubergange im wesentlichen zwischen dem Grundzustand der Molekule und dem ersten Schwingungsniveau induziert, wobei im nahen Infrarot (NIR) Ubergange auf hohere Niveaux sowie Kombinationen von Ubergiingen durch elektromagnetische Strahlung stimuliert werden. Diese unterschiedlichen Schwingungsanregungen legen die ansonsten willkurliche Unterteilung in die obengonann ten Wellenlangenbereiche nahe.

Through a number and angular momentum projected cranked HFB calculation for 158 Dy we find that the collective and single-particle (aligned v i 13 2 angular momenta are antialigned against each other in the low-spin part of the s-band. Consequently in this part of the band the g -factors assume large negative values ( g 2 ≈ − 1.3) which could be used as a signature in the experimental detection of this low-spin high-energy region.

Performing a number-projection calculation on the cranked Hartree-Fock-Bogoliubov (CHFB) wave functions for 158Dy magnetic moments and pair fields have been calculated for this nucleus. These results do not differ significantly from the usual (number-unprojected) CHFB theory. So, in view of this, we have studied the high-spin behaviour of five nuclei 154Sm, 158Gd, 158Dy, 164Dy, and 166Er within the framework of the self-consistent CHFB approach without number projection. The variation of g-factor and pair correlation as a function of angular momentum is studied for spin up to 20+ with a particular emphasis to see the mutual differences amongst these nuclei. Calculated g-factors are in good qualitative agreement in all the cases wherever experimental data are available and inclusion of quadrupole pairing improves the agreement. There is always a minimum in g at I ≈ 14 caused by rotation alignment of ν i 13 2 orbitals. This is followed by an increase due to proton alignment.

We study the density behavior of topological chiral bags in a baryonic environment. Using a lattice and a Wigner-Seitz approach we are able to obtain information about the reliability of both schemes by comparing with experimental data. Having shown reasonable results for nuclear matter we apply both types of calculations to investigate the phase transition between nuclear matter and quark matter.

Using self-consistent solutions of the constrained Hartree-Fock-Bogolyubov method (CHFB), we treat time-odd terms taken from the Skyrme hamiltonian within first-order perturbation theory and obtain new quasiparticle levels. It is shown that the new terms are very important at high spins. Moreover, with roughly-fitted parameters, they lead to better agreement with the experimentally determined yrast and alignment plots.

We show how one can determine the sign of the matrix element of a symmetry operator between Bogoliubov states and discuss the numerical effect.

Using particle number and spin projected cranked Hartree-Fock-Bogoliubov (CHFB) wavefunctions in the generator coordinate method (GCM) with the cranking frequency as a GC, the shortcomings of the usual CHFB theory are removed and the ground as well as the s band are studied simultaneously. In particular, the variation of the g factor as a function of spin is studied for both the bands for a backbending nucleus 158 Dy.

Using cranking techniques a variety of baryon observables are calculated within the framework of the chiral bag model. Effects from valence quarks, mesons and the quark Dirac sea are included. Results for the NΔ mass splitting and nucleon magnetic moments are found to be relatively insensitive to the bag radius.

The energy and bag radius of a six-quark configuration are obtained from a topological chiral soliton model. The calculation shows that three and six quark systems in this model behave much as those in the MIT bag model.

The smearing of the discrete mode sums leading to the Casimir energy and other vacuum quark contributions to baryon observables in the chiral bag model is shown to give smooth densities dominated by low-energy contributions. This observation provides support for methods previously adopted for the elimination of divergences in such calculations and leads to significant numerical improvements over standard mode sum techniques.

The theory of deconvolution of infra-red spectra is presented and illustrated using milk protein spectra. The advantage of this method is impressively demonstrated and its relevance for dairy farming shown using a simple example, the cooling of milk.

Employing a pairing-plus-quadrupole interaction hamiltonian and projecting out good angular momentum states from the cranked Hartree-Fock-Bogoliubov (CHFB) intrinsic wave functions the yrast spectra of 158Dy and 168Yb are calculated up to moderately high spins (Imax = 16) as to include the backbending region. Then the variation of pairing correlation, g-factor and rotational alignment of neutron spin as a function of total angular momentum is studied. The effect of particle number projection on the spin-projected CHFB wave functions is also investigated and is found to be unimportant for the calculation of g-factors. On the other hand, corrections of the excitation energies for number fluctuations in the CHFB wave functions are essential. Furthermore, looking at the distribution of the total projection quantum number K in various cranking wave functions we are able to throw some light on the K ≠ 0 nature of the aligned s-band. A variation-after-spin projection calculation strictly for the axial shape, without cranking, is also carried out for both the nuclei considered here. In the low-spin region this numerically “cheaper” scheme produces energy spectra similar to that of the CHFB method, and may thus be used to readjust the interaction parameters.

In the framework of the adiabatic cranking model we analyse the generator of the low-lying quadrupole vibration. In a first step, we show the connection between the cranking approach and the equations-of-motion method used in RPA. Then we calculate the matrix elements of the generator numerically, and use them to find an approximate analytic expression for the operator itself. We find that the low-lying vibration, as well as a high-lying state, which we analysed in the same manner for comparison, has a very regular behaviour with varying particle number. An easy approximate expression for the generator can be given finally, which for doubly magic nuclei even becomes exact.

Nuclear current distributions for rotational states of heavy nuclei obtained in realistic cranked shell-model calculations with BCS correlations are used to calculate the transverse PWBA form factors for inelastic electron scattering. By keeping the same density but changing the velocity fields the sensitivity of the form factors to the dynamics of nuclear motion is explored. It is found that experiments on the 0 + → 2 + transition alone will not allow a satisfactory determination of the nuclear flow but that an analysis also of the 0 + → 4 + transition will be necessary. For these transitions optimal q -windows are identified.

The transition current distribution for the low-lying 2 + state at 4.085 MeV in 208 Pb obtained in a realistic cranked shell-model calculation is used to calculate the transverse PWBA form factor for inelastic electron scattering to this state. By keeping the same density but changing the velocity field to that of irrotational, incompressible flow the sensitivity of the form factor to the dynamics of nuclear vibrational motion is explored. It is found that the two flow patterns lead to significant, observable differences in the form factors.