Phosphor Thermometry of Alumina-Forming High-Temperature Alloys Using Luminescent Rare-Earth Ions in YAG: Proof of Concept Using a Dispersion of Ce3+ -Doped YAG Particles in a FeCrAl Alloy

Most high-temperature processes require monitoring and controlling temperature, preferably with high precision and good lateral resolution. Here we evaluate the use of the technique commonly known as phosphor thermometry, which exploits the temperature dependent photoluminescence from an inorganic phosphor, for the determination of the temperature of a composite material consisting of the metallic alloy FeCrAl dispersed with phosphor particles of yttrium aluminum garnet (Y3Al5O12, YAG) doped with a small amount of luminescent Ce3+ ions (YAG:Ce3+). The results show that with some optimization and by changing the dopant ion, YAG based phosphor particles offer a unique opportunity to measure the surface temperature of metal alloys with high precision and high lateral resolution, all the way up to the maximum working temperature of alumina-forming high temperature alloys at ca. 1300 \ub0C

A Comparison of the Oxidation and Nitridation Properties of Selected Chromia- and Alumina-Forming Alloys at 800 degrees C

Three FeCrAl alloys and two chromia-formers (a stainless steel, and a Ni-base alloy) have been exposed in four environments (dry air, air + 20% H2O, 20% H-2 + 20% H2O + Ar and 95% N-2 + 5% H-2) for 168 h at 800 degrees C. The corroded samples were investigated by SEM/EDS, XRD and gravimetry, and the formation of CrO2(OH)(2)(g) was measured as a function of time using a denuder technique. The Fe-base alloy formed a Cr-rich protective oxide scale in dry air and wet air but suffered break-away oxidation in 20% H-2 + 20% H2O + Ar. In contrast, the Ni-base alloy suffered extensive NiO formation and internal oxidation in dry air and wet air but formed a protective chromia scale in 20% H-2 + 20% H2O. All three FeCrAl alloys formed protective alumina scales in dry air, wet air and 20% H-2 + 20% H2O + Ar. The FeCrAl alloy Kanthal APMT was severely nitrided in the 95% N-2 + 5% H-2 environment due to defects in the oxide scale associated with RE-rich inclusions which allowed nitrogen to enter the alloy. In contrast, the two Cr-lean FeCrAl alloys Kanthal EF101 and Kanthal EF100 did not suffer nitridation at all

Ground-Based GPS for Validation of Climate Models: The Impact of Satellite Antenna Phase Center Variations

The amount of water vapor in the atmosphere is an important indicator for climate change. Using the Global Positioning System (GPS), it is possible to estimate the integrated water vapor (IWV) above the ground-based GPS receiver. In order to optimally determine the IWV, a correct model of the received signal phase is essential. We have studied the effect of the satellite antenna phase center variations (PCVs) on the IWV estimates by simulating the effect and by studying the estimates of the IWV based on the observed GPS signals. During a period of five years, from 2003 to 2008, a new satellite type was introduced, and it steadily grew in numbers. The antenna PCVs for these satellites deviate from the earlier satellite types and contribute to excess IWV estimates. We find that ignoring satellite antenna phase variations for this time period can lead to an additional IWV trend of about 0.15 kg/m2/year for regular GPS processing

Exploring the Effect of Silicon on the High Temperature Corrosion of Lean FeCrAl Alloys in Humid Air

A new approach to reduce the chromium and aluminium concentrations in FeCrAl alloys without significantly impairing corrosion resistance is to alloy with 1-2 wt.% silicon. This paper investigates the "silicon effect" on oxidation by comparing the oxidation behavior and scale microstructure of two FeCrAl alloys, one alloyed with silicon and the other not, in dry and wet air at 600 degrees C and 800 degrees C. Both alloys formed thin protective oxide scales and the Cr-evaporation rates were small. In wet air at 800 degrees C the Si-alloyed FeCrAl formed an oxide scale containing mullite and tridymite together with alpha- and gamma-alumina. It is suggested that the reported improvement of the corrosion resistance of Al- and Cr-lean FeCrAl\u27s by silicon alloying is caused by the appearance of Si-rich phases in the scale

Efficacy of an external chromia layer in reducing nitridation of high temperature alloys

Six high temperature alloys have been exposed in N2/H2 environments at 900 \ub0C. In order to study the efficacy of a chromia barrier layer against nitrogen ingress, experiments were performed in two environments having the same N2/H2 ratio but slightly different water content, chromia formation being spontaneous in one case only. The samples were evaluated by SEM/STEM/EDX, XRD, gravimetry and GD-OES. The presence of an external chromia scale reduced nitridation of the alloy by 50–95%. Furthermore, in the presence of a continuous alumina layer no nitridation of the alloy was detected

Identification of Achaete-scute complex-like 1 (ASCL1) target genes and evaluation of DKK1 and TPH1 expression in pancreatic endocrine tumours

<p>Abstract</p> <p>Background</p> <p><it>ASCL1 </it>role in pancreatic endocrine tumourigenesis has not been established. Recently it was suggested that ASCL1 negatively controls expression of the Wnt signalling antagonist <it>DKK1</it>. Notch signalling regulates expression of TPH1, the rate limiting enzyme in the biosyntesis of serotonin. Understanding the development and proliferation of pancreatic endocrine tumours (PETs) is essential for the development of new therapies.</p> <p>Methods</p> <p><it>ASCL1 </it>target genes in the pancreatic endocrine tumour cell line BON1 were identified by RNA interference and microarray expression analysis. Protein expressions of selected target genes in PETs were evaluated by immunohistochemistry.</p> <p>Results</p> <p>158 annotated <it>ASCL1 </it>target genes were identified in BON1 cells, among them DKK1 and TPH1 that were negatively regulated by ASCL1. An inverse relation of ASCL1 to DKK1 protein expression was observed for 15 out of 22 tumours (68%). Nine tumours displayed low ASCL1/high DKK1 and six tumours high ASCL1/low DKK1 expression. Remaining PETs showed high ASCL1/high DKK1 (n = 4) or low ASCL1/low DKK1 (n = 3) expression. Nine of twelve analysed PETs (75%) showed TPH1 expression with no relation to ASCL1.</p> <p>Conclusion</p> <p>A number of genes with potential importance for PET tumourigenesis have been identified. <it>ASCL1 </it>negatively regulated the Wnt signalling antagonist <it>DKK1</it>, and <it>TPH1 </it>expression in BON1 cells. In concordance with these findings DKK1 showed an inverse relation to ASCL1 expression in a subset of PETs, which may affect growth control by the Wnt signalling pathway.</p

The Expression of BAFF, APRIL and TWEAK Is Altered in Eczema Skin but Not in the Circulation of Atopic and Seborrheic Eczema Patients

The TNF family cytokines BAFF (B-cell activating factor of the TNF family) and APRIL (a proliferation-inducing ligand) are crucial survival factors for B-cell development and activation. B-cell directed treatments have been shown to improve atopic eczema (AE), suggesting the involvement of these cytokines in the pathogenesis of AE. We therefore analyzed the expression of these TNF cytokines in AE, seborrheic eczema (SE) and healthy controls (HC). The serum/plasma concentration of BAFF, APRIL and a close TNF member TWEAK (TNF-like weak inducer of apoptosis) was measured by ELISA. The expression of these cytokines and their receptors in skin was analyzed by quantitative RT-PCR and immunofluorescence. Unlike other inflammatory diseases including autoimmune diseases and asthma, the circulating levels of BAFF, APRIL and TWEAK were not elevated in AE or SE patients compared with HCs and did not correlate with the disease severity or systemic IgE levels in AE patients. Interestingly, we found that the expression of these cytokines and their receptors was altered in positive atopy patch test reactions in AE patients (APT-AE) and in lesional skin of AE and SE patients. The expression of APRIL was decreased and the expression of BAFF was increased in eczema skin of AE and SE, which could contribute to a reduced negative regulatory input on B-cells. This was found to be more pronounced in APT-AE, the initiating acute stage of AE, which may result in dysregulation of over-activated B-cells. Furthermore, the expression levels of TWEAK and its receptor positively correlated to each other in SE lesions, but inversely correlated in AE lesions. These results shed light on potential pathogenic roles of these TNF factors in AE and SE, and pinpoint a potential of tailored treatments towards these factors in AE and SE

Effect of local anaesthesia and/or analgesia on pain responses induced by piglet castration

<p>Abstract</p> <p>Background</p> <p>Surgical castration in male piglets is painful and methods that reduce this pain are requested. This study evaluated the effect of local anaesthesia and analgesia on vocal, physiological and behavioural responses during and after castration. A second purpose was to evaluate if herdsmen can effectively administer anaesthesia.</p> <p>Methods</p> <p>Four male piglets in each of 141 litters in five herds were randomly assigned to one of four treatments: castration without local anaesthesia or analgesia (C, controls), analgesia (M, meloxicam), local anaesthesia (L, lidocaine), or both local anaesthesia and analgesia (LM). Lidocaine (L, LM) was injected at least three minutes before castration and meloxicam (M, LM) was injected after castration. During castration, vocalisation was measured and resistance movements judged. Behaviour observations were carried out on the castration day and the following day. The day after castration, castration wounds were ranked, ear and skin temperature was measured, and blood samples were collected for analysis of acute phase protein Serum Amyloid A concentration (SAA). Piglets were weighed on the castration day and at three weeks of age. Sickness treatments and mortality were recorded until three weeks of age.</p> <p>Results</p> <p>Piglets castrated with lidocaine produced calls with lower intensity (<it>p </it>< 0.001) and less resistance movements (<it>p </it>< 0.001) during castration. Piglets that were given meloxicam displayed less pain-related behaviour (huddled up, spasms, rump-scratching, stiffness and prostrated) on both the castration day (<it>p </it>= 0.06, n.s.) and the following day (<it>p </it>= 0.02). Controls had less swollen wounds compared to piglets assigned to treatments M, L and LM (<it>p </it>< 0.001). The proportion of piglets with high SAA concentration (over threshold values 200, 400 mg/l) was higher (<it>p </it>= 0.005; <it>p </it>= 0.05) for C + L compared to M + LM. Ear temperature was higher (<it>p </it>< 0.01) for controls compared to L and LM. There were no significant treatment effects for skin temperature, weight gain, sickness treatments or mortality.</p> <p>Conclusions</p> <p>The study concludes that lidocaine reduced pain during castration and that meloxicam reduced pain after castration. The study also concludes that the herdsmen were able to administer local anaesthesia effectively.</p