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In recent years, Fused Filament Fabrication (FFF) of feedstock comprising metal powder and a polymer binder system attracted more and more attention as an extrusion-based Additive Manufacturing method. Allowing for the production of intricate geometries at reasonably low cost, FFF and subsequent debinding and sintering is an attractive solution for producing complex parts made of metals or ceramics. This study investigates the FFF, debinding and sintering process chain for 1.2083 (AISI 420) tool steel. The effect of printing temperature, printing speed and filament feed rate on the density of the green body was evaluated. With regard to the subsequent solvent debinding the required time for complete binder removal was determined as a function of the maximum part thickness. Based on a thermogravimetric analysis (TGA) the decomposition behavior of the remaining insoluble binder was monitored and accordingly a temperature program for the thermal debinding was derived. The sintering curve was determined by dilatometry. Finally, the capability of the process is demonstrated by manufacturing an impeller geometry and examining the resulting microstructure and hardness of the material.

Zooplankton from clear alpine lakes is exposed to stressful levels of solar UV radiation (UVR). As these pelagic organisms experience high UVR and large changes in solar radiation conditions between ice‐free and ice‐cover periods, they have evolved various strategies to minimize UVR exposure and damage. Here, we studied the relation between photoprotection levels (mycosporine‐like amino acids, carotenoids), antioxidant capacities, and gene expression of heat shock proteins (hsps) as indicator of stress in the copepod Cyclops abyssorum tatricusduring the course of a year. Expression of hsp60, hsp70, and hsp90was measured in the field (baseline expression [BE]) and after UVR exposure in the laboratory. The BE differed among genes and seasons (hsp60: high during summer, hsp70and hsp90: high during the ice‐cover period). The gene expression of hsp70was upregulated after exposure to UVR (up to 5.2‐fold change), while hsp60and hsp90were only constitutively expressed. A strong seasonal pattern was found in the photoprotective compounds and antioxidant capacities, with highest levels during the ice‐free period. The extent of upregulation of hsp70gene expression increased with decreasing photoprotection levels and peaked 24 h post UVR exposure (9.6‐fold change) at the time of lowest photoprotection (February). Our data suggest that hsp70gene expression is modulated by seasonal plasticity in photoprotection. This ability of adequate stress response is essential for survival in highly variable ecosystems such as alpine lakes.

Surface treatments used in the daily manufacturing of parts for the automotive industry are selected to serve functional and decorative requirements achieved of mass production. Increased loads (mechanical, thermal etc.), longer life time, weight reduction, friction reduction, and corrosion resistance are demanded for modern automotive systems. Within the last decade, improved and new deposition techniques were developed in PVD, PECVD, thermochemical heat treatment and thermal spraying. These new treatments are becoming more and more common in powertrain and engine applications. Generating optimized surfaces for different types of substrate materials (e.g. Al‐ alloys, case hardened steels etc.) and geometries (e.g. bores) also impacts the running costs. Due to the new developments within these competing surface treatments, it becomes more and more common to substitute traditional treatment‐substrate‐systems with advanced treatments. Both the application potential and selected examples of different surface treatments will be shown. Aspects of the internal coating of bores inside the engine by plasma spraying, features of the corrosion protection of parts for the powertrain by the IONITOX process and piston ring treatments are discussed in more detail.

Surface treatments used in daily manufacturing of parts for the automotive industry are selected to serve functional and decorative requirements achieved of mass production. Increased loads (mechanical, thermal etc.), longer life time, weight reduction, friction reduction, and corrosion resistance are demanded for modern automotive systems. Within the last decade, improved and new deposition techniques were developed in PVD, PECVD, thermochemical heat treatment and thermal spraying. These new treatments are becoming more and more common in powertrain and engine applications. Generating optimized surfaces for different types of substrate materials (e.g. Al‐ alloys, case hardened steels etc.) and geometries (e.g. bores) also impacts the running costs. Due to the new developments within these competing surface treatments, it becomes more and more common to substitute traditional treatment‐substrate‐systems with advanced treatments. Both the application potential and selected examples of different surface treatments will be shown. Aspects of the internal coating of bores inside the engine by plasma spraying, features of the corrosion protection of parts for the powertrain by the IONITOX process and piston ring treatments are discussed in more detail.

AlTiN coatings were developed over the last 10 years mainly for cutting applications. Besides composition and architecture of AlTiN coatings also PVD technology based on the reactive cathodic vacuum arc evaporation was permanently improved in view of various application fields. Different basic processes were developed in appropriate PVD units to cover wide spread process demands. Both, low temperature processes for decorative coatings including deposition on galvanized plastics as well as high temperature processes for cemented carbide tools can be realized with optimized processes. This paper presents PVD units and selected applications like gear hobs, broaches, ball end mills, cutting blades, forming tools and decorative coatings.

Komplexe des Typs Mn2(CO)8E(CF3)2E′R, in denen die Gruppen E(CF3)2und E′R als Brückenliganden fungieren, werden entweder durch direkte Umsetzung von Mn2(CO)10mit (F3C)2EE′R (E = P, As; E′ = S, Se, Te) oder durch Substitution der Iodbrücke in den Vertretern Mn2(CO)8E(CF3)2I mit Quecksilberverbindungen Hg(E′R)2dargestellt. In der Regel weisen die Zweikernsysteme viergliedrige Heterocyclen (Mn2EE′) auf. Bei den Umsetzungen von Mn2(CO)10mit (F3C)2PE′P(CF3)2(E′ = S, Se) werden allerdings Fünfringe [Mn2P(PE′)] erhalten. Die Verbindungen wurden durch spektroskopische (NMR, IR, MS) und elementaranalytische (C, H) Untersuchungen sowie exemplarisch durch Röngenbeugung an Einkristallen charakterisiert. Das pyramidale Mn2E′R‐Fragment zeigt in Lösung dynamisches Verhalten durch Inversion zwischen zwei identischen Strukturen.

A microgalvanic method for metal filling of etched ion tracks in organic foils on large areas is described. The method and the used galvanic cell permit the deposition of stable standing individual metal whiskers with high aspect ratio and a density of 105–108per cm2on an area of 12.5 cm2. The method was verified with copper and it is suitable also for various other metals. It can be applied for the replication of etched ion tracks and for the fabrication of microstructures containing large numbers of individual metal whiskers.

A principle possibility is demonstrated to apply the ion track membranes as a template for the crystallization of inorganic salts. As an example, potassium iodide has been grown in a matrix of etched ion tracks produced in polycarbonate foils. Arrays of stable free-standing cylindrical microcolumns are observed after dissolution of the organic matrix. They represent single crystals oriented with their 〈100〉or 〈110〉crystallographic directions along the cylinder axes. Possible ways to govern their predominant orientations are briefly discussed.

Perfluormethylphosphor‐ und ‐arsen‐Verbindungen des Typs (F3C)2EE′R (E = P, As; E′ = S, Se, Te; R = organische Gruppen) werden entweder durch Dismutation (Metathese) aus den Edukten E2(CF3)4und (RE′)2oder durch Umsetzung der Iodverbindungen (F3C)2EI mit Quecksilber(II)‐organosulfaniden Hg(SR)2dargestellt und durch spektroskopische (1H‐, 19F‐, 31P‐NMR; IR; MS) sowie analytische Untersuchungen (C, H) charakterisiert.

Applying the indirect fluorescent antibody technique to the infective stages of the hookwormAncylostoma caninum, it appeared that they do not show IgG antibody binding when serum from dogs infected withA. caninum was used in the test (antiserum). However, inhibiting these stages metabolically with azide or with low temperatures, IgG antibody binding to the outer surface was observed. When the inhibitory factors were removed, shedding of fluorescent substances was seen, which were obviously coming from the outer surface of the larvae. This suggests that shedding of the antigen might occur.

The Indirect Fluorescent Antibody Technique (IFAT) and the Indirect Immuno Peroxidase Technique (IIPT) have been applied to cryostat sections and intact stages of the hookworm speciesAncylostoma caninum with sera from infected dogs. Especially the role of the body surface (=cuticle (cortex, matrix, basal layer) and hypodermis) in immunity was studied. Using cryostat sections and dead intact stages as the antigen, specific antibody binding was demonstrated round the ovum membrane and the cuticle of all stages of this hookworm species. Cryostat sections of adult worms showed, that it probably is not the cuticle itself that is antigenic, but that the specific reaction that is observed consisted of a layer, covering the cortex of the cuticle. Infective and parasitic living stages, however, showed no antibody binding in contrast to the free-living stages in which specific antibody binding was demonstrated.

(Cr:Al)N coatings were deposited using two cathodic vacuum arc evaporators fitted with chromium and aluminium cathodes. Both monolayer and multilayer coatings were deposited with different aluminium content. Selected mechanical and tribological properties of the coating were investigated as well as the oxidation behaviour. It is shown that the oxidation rate decreases with increasing aluminium content. The hardness of the (Cr:Al)N coating is higher than that of CrN coatings.

Single and dual energy CT (75 and 125 kVp) measurements of density were made on the excised lumbar vertebrae (L5) of oophorectomized (n = 17) and control (n = 19) monkeys. The single-energy results at 75 and 125 kVp indicated an annual bone diminution of 9.1 and 10.9, respectively, but the dual-energy determination showed only a 6.6/year loss. The difference between single- and dual-energy results could be explained by a putative increase in marrow fat of slightly > 100 mg/cm3. Changes in single-energy CT density with oophorectomy and aging may be substantially overestimated.

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Infective hookworm larvae ofAncylostoma caninum showed chemotaxis on agar plates in a dog serum gradient. This chemotactic behaviour remain unaltered using an ultrafiltrated serum fraction with a molecular weight less than 500. Gelfiltration of this ultrafiltrated fraction revealed a factor with a molecular weight of 480 causing chemotaxis. The chemotactic activity of the factor was destroyed after a pronase treatment. We conclude that the factor could be a polypeptide.

Infective hookworm larvae ofAncylostoma caninum showed chemotaxis when applied on agar plates in a dog serum gradient. The factor(s) that caused this chemotaxis was thermostable and dialysable against PBS. Using ultrafiltration to separate dog serum in several fractions each with a different molecular weight, it was shown that the factor(s) causing chemotaxis had a molecular weight less than 500 Dalton.

Summary: The hairless metacarpal foot pads of six hookworm-free puppies were exposed to infective larvae of Ancylostoma braziliense. Serial sections of the biopts stained with Harris' haematoxylin and eosin showed that the infective larvae are able to penetrate the toughest region of canine skin. Pores of eccrine sweat glands did not seem to constitute sites of entry and no larvae were detected in these glands. Larvae were only observed in the epidermis. The histopathology of the infected skin of the foot pads of the puppies was similar to that in human skin with “creeping eruption” as described by Flleborn (1927). The biopts appeared to consist of hairy skin as well. In the unexposed adjacent hairy skin of the foot pads, larvae were also observed. They were found in the epidermis, hair follicle systems and dermis, suggesting that the migration from the epidermis into deeper tissue depends on the presence of the hair follicle systems.

Purpose: To define the prevalence of popliteal artery occlusion during active plantar flexion in normally active and highly trained young volunteers by measuring plantar flexion force and to assess the force level associated with popliteal artery occlusion. Methods: Eighty-four limbs of 42 healthy subjects were studied. Eighteen subjects were highly trained athletes, and 24 were normally active persons. Plantar flexion was progressively performed in prone position against a scale. Plantar flexion force was measured in kilograms. After determination of the maximum strength (P"m"a"x) of plantar flexion force, the level necessary to occlude the popliteal artery (P"o"c"c"l) was assessed by continuously monitoring that vessel using color duplex sonography. Results: Occlusion of the popliteal artery during plantar flexion was observed in 88.1% of the subjects and 77.4% of the limbs. No significant differences in prevalence were found between athletes and normally active subjects. The popliteal artery occluded at a mean plantar flexion force of 45.1 +/- 11.5 kg, which corresponded with 70.1% +/- 16.8% of the maximum force exerted during the provocation test. P"o"c"c"l was not significantly different between lower limbs of athletes and nonathletes. Although in lower limbs of athletes the popliteal artery occluded at a significantly lower relative force as compared with normally active subjects (65.6% +/- 17.4% vs 74.5% +/- 17.4% of P"m"a"x; p < 0.02), the difference was a result of two extremely low values found in a female athlete. Conclusion: Positional occlusion of the popliteal artery during active plantar flexion is commonly found in young healthy volunteers. Prevalence of the phenomenon depends on the force level exerted during active plantar flexion. Popliteal artery occlusion during active plantar flexion is not more frequent in athletes and occurs at a similar force level than in normally active subjects. (J Vasc Surg 1997 26:281-7.)

The plasma generated by an arc-enhanced glow discharge is applicable to various surface treatments. Ion cleaning procedures are mostly carried out in argon or argon plus hydrogen gas mixtures before other treatments are made. Possible treatments are nitriding before deposition of a hard coating and deposition of hard carbon coatings. The paper presents Langmuir probe measurements and the results of optical emission spectroscopy (OES). It is shown that the wide-range OES measurements (300–800 nm) can be used to record sensitively variations of plasma states. The following plasmas were investigated: argon, argon plus hydrogen, argon plus nitrogen and argon plus nitrogen and acetylene. The plasma distribution was measured near and in the space between two circular saw blades.

Polycarbonate, polyimide, and glass samples were irradiated with heavy ions in the 11.4-14.0 MeV/amu energy range at the UNILAC of GSI. After etching and partly coating the specimens with a thin gold layer, ion tracks were studied with scanning force microscopy, including imaging in the lateral-force mode. Results on pore features such as the radius as a function of etching time are presented.

Magnetic garnet Y3Fe5O12 and magnetic ferrite BaFe12O19 have been irradiated at room temperature by Kr and Xe ions using the GANIL accelerator at Caen and by U ions using the Unilac accelerator at Darmstadt. These experiments allow to cover a wide range of electronic stopping power values (between 7 MeV/μm and 45 MeV/μm) using the ion beam at energy between 40 MeV/a.m.u. and 8 MeV/a.m.u. Transmission Mössbauer spectrometry has been used to determine the damage cross section A for the corresponding value of electronic stopping power. High resolution electron microscopy observations confirm the A determination for the highest value of dE/dx. The main feature is the appearance of a saturation in the damage efficiency ε = A/dE/dx above an electronic stoping power value TM. Using all the previous results, damage evolution and damage morphology description will be proposed and comparison with the chemical etching sensitivity of the magnetic garnet will be done.

Dislocation free Si crystals implanted with 16 MeV/n U-ions using the Darmstadt accelerator have been investigated by X-ray diffraction methods. X-ray section topography showed that the induced damage range is a little larger than the theoretically calculated U-ion range. The created defects cause the volume increase in the implanted part of the crystals. For the dose 1.9·1012i/cm2 the increase of lattice constant is 1.4·10-5±5·10-6 Å and for the dose 4.4·1012i/cm22.4·10-5± 5·10-6 Å.

Different forming processes were investigated to evaluate the possibility of reducing the usage of lubricants. A successful way to minimize the consumption of lubricants is to use tools which are covered with PVD hard coatings deposited by the cathodic vacuum arc evaporation. The most promising coating in use was the CrN coating. It becomes evident that neat stamping oils may be substituted by water diluted emulsions when working with coated tools in the forming process. Four main effects were observed: reduction of lubricants up a factor to 85% of additive concentration, increase of tool life up a factor to 169 (first polishing), increase of working speed up a factor to 2 and reduction of washing processes. These effects lower the production costs and decrease the environmental charge.

Nuclear fusion is a physical process in which the nuclei of heavy hydrogen atoms (deuterium, tritium) are united by fusion to become an atomic nucleus of helium while releasing large amounts of energy. The energy emitted by the Sun is generated by nuclear fusion. In nuclear fusion research, reproduction of that process in a technical scale device, the fusion reactor, at high temperatures, is attempted. In this review a short outline is given of the national, European and worldwide technology programmes initiated during the last decade. The contributions which the Karlsruhe Nuclear Research Centre makes to these programmes on the basis of experience accumulated over several decades are described. The cooperation of specialists from various disciplines in the two central activities of magnet technology and the nuclear part of the fusion reactor, the so called blanket, is described more fully. In conclusion, the most important milestones on the way to the commercial fusion reactor are indicated, and the critical problems faced in development of the technology are pointed out.

To improve the adhesion of a metal coating to Teflon (polytetrafluoroethylene, PTFE), the ion beam technique has been used. Adhesion enhancement was obtained by irradiation of the Cu/Teflon interface with heavy ions in the GeV energy range. XPS analysis gave evidence for the long-range transport of Cu atoms into the polymer. Heating the Cu/Teflon sample after ion irradiation led to even stronger bonding between Cu and Teflon.

Research was performed into the prevalence of concurrent parasite infection among 23 patients with onchocerciasis and 13 onchocerciasis-negative controls in Sierra Leone, West Africa. Stools, urine sediments and bloodsmears were examined for ova, parasites and microfilariae. Results showed the presence of Hookworm, Schistosoma mansoni, Trichuris trichiura and Ascaris lumbricoides. A positive relationship was found between O. volvulus and Hookworm infection. The effects of polyparasitism on immunodiagnosis and the need for further research is discussed.

Thermal9Be+ (I=3/2) ions are polarized by direct optical pumping in He buffer gas. Observation of?gDF=± 1 transitions yields for the hyperfine splitting frequencyvhfs(9Be+, 1s2 2s2S1/2)=1250018(5) kHz. The result is discussed with regard to predictions of recent theoretical calculations and of the Fermi-Segré formula for the ground state hfs of the Li isoelectronic sequence.

Fractional hyperfine density shifts (fds) for137Ba+ (I=3/2) ions are measured by means of direct optical pumping in noble gas buffers. The results for the fds (137Ba+, 6s2S1/2) in units of 10-9/Torr (0 ‡C) (measured at temperatures between 375 and 395 K) are: + 7(7) (He), -74(8) (Ne), -825(80) (Ar), -1 500(200) (Kr), and < -1600 (Xe). These shifts for the137Ba+ ion are considerably more negative than those for the isoelectronic137Cs atom. It is shown that this difference can be explained by taking into account the additional charge induced interaction. The hyperfine splitting frequency of the unperturbed137Ba+ 6s2S1/2 state is extrapolated tov0=8037741.6(6)kHz.

Abstract: Several noninvasive measurement methods are used for evaluation of metabolic disease. Single-photon (125I) scans of the peripheral skeleton are useful in some diseases but are ineffective in osteoporosis (even on the distal radius or os calcis) because they cannot predict spinal or femoral density. Also, peripheral measurements show high percentages of false negatives, that is many patients with fractures have normal peripheral density. Dual-photon (153Gd) scans of the spine, femur, and total skeleton are precise and accurate (2% error) and provide direct measurements of bone strength at fracture sites. This gives the best discrimination of abnormality and the most sensitive monitoring. Quantitative computed computed tomography (QCT) allows measurement of the spine but not the critical proximal femur area. QCT has a large accuracy error because (a) the limited are measured (under 5 cm3) fails to represent the total vertebral body, (b) technical errors and (c) variable fat and osteoid influence the results.

AbstractWhen high-energetic ions pass a solid they can induce damage in the material structure by deposition of a huge amount of energy along their paths. Depending upon the kind of material these so-called latent tracks can be etched by suitable etchants. In this work latent tracks in polymers are investigated for the first time by transmission electron microscopy (TEM). Bulk polymeric material and thin sections of HDPE, LDPE, LLDPE and PP, prepared by cryo-ultramicrotomy were irradiated with high-energetic ions (U, Xe, Zn) and after chemical staining investigated by TEM. The cross sections of the ion tracks appear as circularly shaped spots in the amorphous regions with diameters of about 3–8 nm. The mean track diameter increases with the atomic number of the ions. Inside the crystalline lamellae the tracks are elliptically shaped with the long axis in parallel orientation to the extended macromolecules (c-axis). This result indicates breaking and relaxation of macromolecular segments inside the lamellae.