Challenges of temperature measurement during the friction stir welding process

The exact determination of the process zone temperature can be considered as an increasingly important role in the control and monitoring of the friction stir welding process (FSW). At present, temperature measurement is carried out with the aid of a temperature sensor integrated into the tool (usually thermocouples). Since these cannot be attached directly to the joining area, heat dissipation within the tool and to the environment cause measurement deviations as well as a time delay in the temperature measurement. The article describes a process and the challenges that arise in this process, how a direct temperature measurement during the process can be achieved by exploiting the thermoelectric effect between tool and workpiece, without changing the tool by introducing additional temperature sensors

Association of Common Polymorphisms in GLUT9 Gene with Gout but Not with Coronary Artery Disease in a Large Case-Control Study

BACKGROUND: Serum uric acid (UA) levels have recently been shown to be genetically influenced by common polymorphisms in the GLUT9 gene in two genome-wide association analyses of Italian and British populations. Elevated serum UA levels are often found in conjunction with the metabolic syndrome. Hyperuricemia is the major risk factor for gout and has been associated with increased cardiovascular morbidity and mortality. The aim of the present study was to further elucidate the association of polymorphisms in GLUT9 with gout and coronary artery disease (CAD) or myocardial infarction (MI). To test our hypotheses, we performed two large case-control association analyses of individuals from the German MI Family Study. METHODS AND FINDINGS: First, 665 patients with gout and 665 healthy controls, which were carefully matched for age and gender, were genotyped for four single nucleotide polymorphisms (SNPs) within or near the GLUT9 gene. All four SNPs demonstrated highly significant association with gout. SNP rs6855911, located within intron 7 of GLUT9, showed the strongest signal with a protective effect of the minor allele with an allelic odds ratio of 0.62 (95% confidence interval 0.52-0.75; p = 3.2*10(-7)). Importantly, this finding was not influenced by adjustment for components of the metabolic syndrome or intake of diuretics. Secondly, 1,473 cases with severe CAD or MI and 1,241 healthy controls were tested for the same four GLUT9 SNPs. The analyses revealed, however, no significant association with CAD or with MI. Additional screening of genome-wide association data sets showed no signal for CAD or MI within the GLUT9 gene region. CONCLUSION: Thus, our results provide compelling evidence that common genetic variations within the GLUT9 gene strongly influence the risk for gout but are unlikely to have a major effect on CAD or MI in a German population

Temperature Dependence of the Dynamic Parameters of Contact Thermometers

Contact thermometers are used in a wide temperature range as well as under various media and environmental conditions. The temperature can range from −200 °C to about 1500 °C. In this case, the dynamic parameters (time percentage values tx and time constants τ) depend on temperature. Several effects are superimposed. Constructional and material properties of the thermometer and the installation location affect the dynamic behavior as well as the type and material properties of the object to be measured. Thermal conductivity λ, specific heat capacity c, and density ρ depend on temperature. This temperature dependence can be mutually compensated for (see Section 3). At the same time, the dynamic behavior is also influenced by the temperature-dependent parameters of the medium. When the thermometers are installed in air, for example, the heat transfer coefficient α decreases with increasing temperature, owing to the temperature-dependent material data of the air, at constant speed v. At the same time, heat radiation effects are so strong that the heat transfer improves despite the decreasing convective heat transfer coefficient. In this paper, a number of examples are used to establish a model for the temperature dependence of the dynamic parameters for various thermometer designs. Both numerically and experimentally determined results for the determination of the dynamic characteristic values are included in the consideration

DOI:10.1068/htwu229

Phase transformations of technically pure metals and two-component alloys in miniature fixed-point crucible

Dissecting aggregation and seeding dynamics of α\alpha-Syn polymorphs using the phasor approach to FLIM

International audienceSynucleinopathies are a heterogenous group of neurodegenerative diseases characterized by the progressive accumulation of pathological α-synuclein ($\alpha$-Syn). The importance of structural polymorphism of $\alpha$-Syn assemblies for distinct synucleinopathies and their progression is increasingly recognized. However, the underlying mechanisms are poorly understood. Here we use fluorescence lifetime imaging microscopy (FLIM) to investigate seeded aggregation of $\alpha$-Syn in a biosensor cell line. We show that conformationally distinct $\alpha$-Syn polymorphs exhibit characteristic fluorescence lifetimes. FLIM further revealed that $\alpha$-Syn polymorphs were differentially processed by cellular clearance pathways, yielding fibrillar species with increased seeding capacity. Thus, FLIM is not only a powerful tool to distinguish different amyloid structures, but also to monitor the dynamic process of amyloid remodeling by the cellular environment. Our data suggest that the accumulation of highly seeding competent degradation products for particular polymorphs may account for accelerated disease progression in some patients

Methoden der Temperaturbestimmung von elektrischen Entladungen bei Öffnungs-Kontaktvorgängen in zündfähigen Gasen

Electrical discharges generated by low voltages of 20 to 40V and currents of 40 to 100mA and occurring between opening electrical contacts in an explosive atmosphere, were investigated by spectroscopy to determine the resulting temperature. These metal-vapor discharges, which are similar to the "short arc", are generated in the internationally standardized spark-testing device according to IEC 60079-11, in order to assess the suitability of electrical components in explosive areas. The temperature is a key parameter of these complex processes in the spark test apparatus. On the one hand, the temperature of the contactmaterials is relevant for the understanding of the necessary preliminary processes before themain discharge. On the other hand the effect of the discharge can be characterized by the electron-, ion- and gastemperature. This article describes the current state of the temperature measurement of these electrical discharges, including the challenges in gaining a deeper understanding of these discharge processes and the thermochemical ignition process. For discharges with 30 V and 100mA and under the specified conditions, excitation temperatures in the range of 3500-5000 K were measured and calculated