Structural Health Monitoring of Adhesively Bonded Pipe-to-Socket Joints by Integration of Polymer Optical Fibers and Their Load-Dependent Transmission Properties.

Adhesively bonded pipe-to-socket joints are used in numerous industrial applications. One example is in the transport of media, e.g.

Enhanced osteogenic differentiation of human mesenchymal stromal cells as response to periodical microstructured Ti6Al4V surfaces.

Titanium-based alloys, for example, Ti6Al4V, are frequently employed for load-bearing orthopedic and dental implants. Growth of new bone tissue and therefore osseointegration can be promoted by the implant's microtopography, which can lead to improved long-term stability of the implant. This study investigates the effect that an organized, periodical microstructure produced by an electron beam (EB) technique has on the viability, morphology, and osteogenic differentiation capacity of human mesenchymal stromal cells (hMSC) in vitro.

Frequency dependence of nonlinear absorption in fused silica measured with picosecond pulses at various focal lengths.

Nonlinear absorption is the key process to generate laser-induced in-volume modifications in transparent dielectrics such as waveguides or three-dimensional data matrix codes. We present a comprehensive parameter study about nonlinear absorption in fused silica using a picosecond laser at various focal lengths. Beginning at a focal length of 100 mm, we measure a strong frequency dependence of the saturation absorption.

Transparent high-pressure nozzles for visualization of nozzle internal and external flow phenomena.

A new design for transparent high-pressure nozzles is presented in this work. This new design enables using the innovative Selective Laser Etching (SLE) method to manufacture transparent nozzles with outstanding accuracy. Therefore, not only the simultaneous visualization of the flow mechanics inside and outside the nozzle is enabled, but the manufacturing method applied also allows for the realization of individual nozzle geometries.

[Bone Cement Adhesion on Ceramic Surfaces - Deactivation of Surfaces and as a Consequence Inefficient Retention of Knee Prostheses Because of Adsorption of Atmospheric Water].

Aim: CoCrMo alloys are contraindicated for sufferers from allergy. For these patients, uncemented and cemented prostheses made of non-allergenic titanium alloy are indicated. Knee prostheses machined from that alloy, however, may have poor tribological behaviour, especially in contact to UHMWPE inlays.

Assessment of the Biological Effects of Welding Fumes Emitted From Metal Active Gas and Manual Metal Arc Welding in Humans.

Objective: Emissions from a particular welding process, metal inert gas brazing of zinc-coated steel, induce an increase in C-reactive protein. In this study, it was investigated whether inflammatory effects could also be observed for other welding procedures.

Methods: Twelve male subjects were separately exposed to (1) manual metal arc welding fumes, (2) filtered air, and (3) metal active gas welding fumes for 6 hours.

[Bone cement adhesion on ceramic surfaces - surface activation of retention surfaces of knee prostheses by atmospheric plasma versus thermal surface treatment].

Aim: CoCrMo alloys are contraindicated for allergy sufferers. For these patients, uncemented and cemented prostheses made of titanium alloy are indicated. Knee prostheses machined from that alloy, however, may have poor tribological behaviour, especially in relation to UHMWPE inlays.

Adhesion of human mesenchymal stem cells can be controlled by electron beam-microstructured titanium alloy surfaces during osteogenic differentiation.

Several studies focusing on bone tissue engineering demonstrated that given microstructuring of an implant surface has a strong effect on its interaction with cells, and their adhesion and differentiation. In the present study, geometrically structured titanium alloy surfaces are shown to be able to guide cell adhesion during differentiation in vitro. For this reason, using an electron beam texturing technique, TiAl6V4 surfaces were selectively targeted in the micrometer range.

Human biomonitoring of aluminium after a single, controlled manual metal arc inert gas welding process of an aluminium-containing worksheet in nonwelders.

Purpose: Several existing field studies evaluate aluminium welding works but no thoroughly controlled exposure scenario for welding fume has been described yet. This study provides information about the uptake and elimination of aluminium from welding fumes under controlled conditions.

Methods: In the Aachen Workplace Simulation Laboratory, we are able to generate welding fumes of a defined particle mass concentration.

Human biomonitoring of chromium and nickel from an experimental exposure to manual metal arc welding fumes of low and high alloyed steel.

Objectives: The uptake and elimination of metals from welding fumes is currently not fully understood. In the Aachen Workplace Simulation Laboratory (AWSL) it is possible to investigate the impact of welding fumes on human subjects under controlled exposure conditions. In this study, the uptake and elimination of chromium or chromium (VI) respectively as well as nickel was studied in subjects after exposure to the emissions of a manual metal arc welding process using low or high alloyed steel.

Biological effects of emissions from resistance spot welding of zinc-coated material after controlled exposure of healthy human subjects.

Objective: Do emissions from a resistance spot welding process of zinc-coated materials induce systemic inflammation in healthy subjects after exposure for 6 hours?

Methods: Twelve healthy male subjects were exposed once for 6 hours either to filtered ambient air or to welding fume from resistance spot welding of zinc-coated material (mass concentration approximately 100 μg m). Biological effects were measured before, after, and 24 hours after exposure.

Results: At the concentrations used in this study, however, the suspected properties of ultrafine particles did not lead to systemic inflammation as reflected by high-sensitivity C-reactive protein or other endpoint parameters under consideration.

Relationship between welding fume concentration and systemic inflammation after controlled exposure of human subjects with welding fumes from metal inert gas brazing of zinc-coated materials.

Objectives: It has been shown that exposure of subjects to emissions from a metal inert gas (MIG) brazing process of zinc-coated material led to an increase of high-sensitivity C-reactive protein (hsCRP) in the blood. In this study, the no-observed-effect level (NOEL) for such emissions was assessed.

Methods: Twelve healthy subjects were exposed for 6 hours to different concentrations of MIG brazing fumes under controlled conditions.

Assessment of the biological effects of welding fumes emitted from metal inert gas welding processes of aluminium and zinc-plated materials in humans.

The aim of this study was to investigate biological effects and potential health risks due to two different metal-inert-gas (MIG) welding fumes (MIG welding of aluminium and MIG soldering of zinc coated steel) in healthy humans. In a threefold cross-over design study 12 male subjects were exposed to three different exposure scenarios. Exposures were performed under controlled conditions in the Aachener Workplace Simulation Laboratory (AWSL).

Number size distribution of fine and ultrafine fume particles from various welding processes.

Studies in the field of environmental epidemiology indicate that for the adverse effect of inhaled particles not only particle mass is crucial but also particle size is. Ultrafine particles with diameters below 100 nm are of special interest since these particles have high surface area to mass ratio and have properties which differ from those of larger particles. In this paper, particle size distributions of various welding and joining techniques were measured close to the welding process using a fast mobility particle sizer (FMPS).

Exposure of healthy subjects with emissions from a gas metal arc welding process: part 3--biological effect markers and lung function.

Background: Metal active gas welding (MAG) is a widely-used welding technique resulting in high emissions of welding fume particles. This study investigated whether short-term exposure to these fume particles results in changes in lung function and early stages of inflammatory reactions.

Methods: Twelve healthy, young male subjects were exposed to MAG fumes for 6 h with three different exposure concentrations in a three-fold cross-over study design.

Exposure of healthy subjects with emissions from a gas metal arc welding process: part 1--exposure technique and external exposure.

Background: Studies concerning welding fume-related adverse health effects in welders are hampered by the heterogeneity of workplace situations, resulting in complex and non-standardized exposure conditions.

Methods: In order to carry out welding fume exposure studies under controlled and standardized conditions, the Aachen Workplace Simulation Laboratory was developed. This laboratory consists of an emission room, in which welding fume is produced, and an exposure room in which human subjects are exposed to these fumes.

Experimental exposure of healthy subjects with emissions from a gas metal arc welding process--part II: biomonitoring of chromium and nickel.

Objectives: The objective of this study was to investigate whether there is a relationship between the external exposure dose of chromium and nickel caused by a metal active gas welding process with a solid high-alloyed steel welding wire and inner exposure of subjects. In order to perform welding fume exposure under controlled and standardized conditions, the investigations were conducted in the "Aachen Workplace Simulation Laboratory".

Methods: To perform biological monitoring of chromium and nickel, blood and urine samples of 12 healthy male non-smokers who never worked as welders were collected before and after a 6-h exposure to ambient air (0 mg/m(3)) and to welding fumes of a metal active gas welding process once with a concentration of the welding fume of 1 mg/m(3) and once with a concentration of 2.

Biological effect markers in exhaled breath condensate and biomonitoring in welders: impact of smoking and protection equipment.

Purpose: The objective of this study was to investigate the effect of welding as well as the impact of smoking and protection measures on biological effect markers in exhaled breath condensate. Additionally, biomonitoring of chromium, aluminium and nickel in urine was performed to quantify internal exposure.

Methods: Exhaled breath condensate (EBC) and urine samples of 45 male welders and 24 male non-exposed control subjects were collected on Friday pre-shift and after 8 h of work post-shift.

Spirometry, impulse oscillometry and capnovolumetry in welders and healthy male subjects.

Background: Welding processes emit fine and ultrafine aerosol particles which are potentially harmful to the lungs of welders. In the past, changes in lung function were mostly determined by conventional spirometry. In this study spirometry was combined with new techniques such as Impulse Oscillometry (IOS) and Capnovolumetry (CVS) in order to assess welding associated changes in lung function.