In Plasma Spray–Physical Vapor Deposition (PS-PVD) process, major fractions of the feedstock powder can be evaporated so that coatings are deposited mainly from the vapor phase. In this work, ...Computational Fluid Dynamics (CFD) results indicate that such evaporation occurs significantly in the plasma torch nozzle and even nucleation and condensation of zirconia is highly possible there. Experimental work has been performed to investigate the nature of the deposits in the PS-PVD process, in particular coatings from condensate vapor and nano-sized clusters produced at two spraying distances of 1000 mm and 400 mm. At long spraying distance, columns in the coatings have pyramidal tops and very sharp faceted microstructures. When the spraying distance is reduced to 400 mm, the tops of columns become relatively flat and a faceted structure is not recognizable. XRD patterns show obvious preferred orientations of (110) and (002) in the coatings sprayed at 400 mm but only limited texture in the coatings sprayed at 1000 mm. Meanwhile, a non-line of sight coating was also investigated, which gives an example for pure vapor deposition. Based on these analyses, a vapor and cluster depositions are suggested to further explain the formation mechanisms of high-quality columnar-structured PS-PVD thermal barrier coatings which have already shown excellent performance in cyclic lifetime test.
Low pressure plasma spraying (LPPS) is a thermal spraying technique that has found a niche for low oxidation products. It uses a low pressure environment (i.e., chamber pressure between 2 and 90 kPa) ...and yields supersonic plasma jets. The enthalpy probe technique is a common measurement method in plasmas. However LPPS jets are difficult to diagnose as their supersonic nature forces the apparition of a shock wave in front of any measuring device inserted in the jet. Incomplete or erroneous assumptions are usually invoked to overcome the difficulties associated with this shock wave and carry out the LPPS jet diagnosis from enthalpy probe measurements. In this work, a new device is designed to gain access to an additional physical quantity, which is needed to assess the aerodynamic non-equilibrium state of the jet. It is combined with enthalpy probe measurements, and the resulting set of experimental data is used with a numerical procedure based on gas dynamics theory, yielding free-stream supersonic plasma jet values from the measurements behind the induced shock wave. The results agree well with the phenomenology of supersonic jets in aerodynamic nonequilibrium. However this new method is restricted by the local thermodynamic equilibrium assumption, which is directly linked with the pressure and temperature conditions of the plasma jet.
High production cost is one of the major barriers to widespread commercialization of solid oxide fuel cells (SOFCs). Thermal spray techniques are a low cost alternative for the production of SOFCs. ...The objective of this work was to evaluate the electrochemical performance of half-cells produced by plasma spraying. The anode was deposited on a porous metallic support by atmospheric plasma spraying (APS) whereas the electrolyte was deposited by plasma spray-thin film (PS-TF) technique which can produce thin and dense coatings at high deposition rates. The cathode was deposited by screen-printing. The electrochemical tests were performed at 650-800°C. Current-voltage characteristics and impedance spectra were measured and analyzed. The impact of electrolyte composition and layer thickness on the gas tightness of the electrolyte and the area specific resistance of the cell is discussed. The results show that the applied thermal spraying techniques are a potential alternative for producing SOFCs.
Background The goal of this study was to investigate the surgical management and outcomes of patients with primary colorectal cancer (CRC) and synchronous liver metastasis (sCRLM). Study Design Using ...a multi-institutional database, we identified 1,004 patients treated for sCRLM between 1982 and 2011. Clinicopathologic and outcomes data were evaluated with uni- and multivariable analyses. Results A simultaneous CRC and liver operation was performed in 329 (33%) patients; 675 (67%) underwent a staged approach (“classic” staged approach, n = 647; liver-first strategy, n = 28). Patients managed with the liver-first approach had more hepatic lesions and were more likely to have bilateral disease than those in the other 2 groups (p < 0.05). The use of staged operative strategies increased over the time of the study from 58% to 75% (p < 0.001). Liver-directed therapy included hepatectomy (90%) or combined resection + ablation (10%). A major resection (>3 segments) was more common with a staged approach (39% vs 24%; p < 0.001). Overall, 509 patients (50%) received chemotherapy in either the preoperative (22%) or adjuvant (28%) settings, with 11% of patients having both. There were 197 patients (20%) who had a complication in the postoperative period, with no difference in morbidity between staged and simultaneous groups or major vs minor hepatectomies (p > 0.05). Ninety-day postoperative mortality was 3.0%, with no difference between simultaneous and staged approaches (p = 0.94). The overall median and 5-year survivals were 50.9 months and 44%, respectively; long-term survival was the same regardless of the operative approach (p > 0.05). Conclusions Simultaneous and staged resections for sCRLM can be performed with comparable morbidity, mortality, and long-term oncologic outcomes.
The production of high quality coatings for fuel cell applications in an industrial scale requires stable, reliable and economically efficient processes. In the recent years, Sulzer Metco has been ...actively developing coating solutions to fulfill the requirements of fuel cells coating production, in particular for SOFC applications based on both metal and ceramic supported cells. This includes the use of new thermal spray technologies such as LPPS®-Thin Film and TriplexPro{trade mark, serif}-200 to produce the functional layers of fuel cells, such as the electrodes, electrolytes and diffusion barrier layers. In parallel, the development of new powder materials specifically designed towards optimized coating process and functionality has shown an improvement of the cell performance. Both coating technologies have a high potential regarding economical coating production on an industrial large volume scale. This paper presents the current status of developments of the advanced coating technologies together with an overview of the used materials and analysis of the applied coatings.
The production of protective coatings on metallic SOFC interconnects using LaSrMnO (LSM) in an industrial scale requires an economically efficient process in order to obtain high quality and reliable ...coatings. The TriplexProTM-200 gun is a new advanced plasma spray torch with three electrodes which provides all the features necessary to apply this type of coatings following the requested productivity and quality for a mass production in an Atmospheric Plasma Spray (APS) process. The LPPS-Thin Film technology uses a high power plasma torch operated in a low pressure environment. This low ambient pressure produces a large plasma jet with unconventional properties allowing the production of thin and dense ceramic coatings. Thus, the technology is best suited to deposit very dense electrolyte layers of Yttria Stabilized Zirconia (YSZ) for improved cell performance. Moreover, the large plasma plume in the LPPS-TF process allows a very efficient coating production on large areas.
A restricted lesion of the hand area in the primary motor cortex (M1) leads to a deficit of contralesional manual dexterity, followed by an incomplete functional recovery, accompanied by plastic ...changes in M1 itself and in other cortical areas on both hemispheres. Using the marker SMI-32 specific to pyramidal neurons in cortical layers III and V, we investigated the impact of a focal unilateral M1 lesion (hand representation) on the rostral part (F6) and caudal part (F3) of the supplementary motor area (SMA) in both hemispheres in nine adult macaque monkeys compared with four intact control monkeys. The M1 lesion induced a consistent interhemispheric asymmetry in density of SMI-32-positive neurons in F3 layer V (statistically significant in 8 of 9 lesioned monkeys), highly correlated with the lesion volume and with the duration of functional recovery, but not with the extent of functional recovery itself. Such interhemispheric asymmetry was neither present in the intact monkeys, as expected, nor in F6 in all monkeys. In addition, the M1 lesion also impacted on the basal dendritic arborization of F3 layer V neurons. Neuronal density was clearly less affected by the M1 lesion in F3 layer III compared with layer V. We interpret the remote effect of M1 lesion onto the density of SMI-32-positive neurons and dendritic arborization in the SMAs bilaterally as the consequence of multiple factors, such as changes of connectivity, diaschisis and various mechanisms involved in cortical plasticity underlying the functional recovery from the M1 lesion.
The motor system of macaque monkeys, in addition to be similarly organized as in humans, is a good candidate to study the impact of a focal lesion of the main contributor to voluntary movements, the primary motor cortex (M1), on non-primary motor cortical areas also involved in manual dexterity, both at behavioral and structural levels. Our results show that a unilateral permanent lesion of M1 hand area in nine monkeys affects the interhemispheric balance of the number of SMI-32-positive pyramidal neurons in the cortical layer V of the supplementary motor area, in a way strongly correlated to the lesion volume and duration of the incomplete functional recovery.
Low Pressure Plasma Spraying (LPPS) is nowadays a well-established thermal spray process with a broad variety of important applications for functional surface coatings. The operating pressure for ...LPPS processes can vary in a wide range from typically 200 mbar down to only a few mbar. This leads to unconventional properties of the plasma jet, in terms of supersonic flow with strong shock structure at moderate pressure, towards rarefaction and frozen flow at very low pressure. In order to optimize and control the spray processes for specific applications, it is necessary to understand the underlying physical mechanisms. However, so far only limited knowledge has been established on the plasma jet properties and its interaction with the spray particles in LPPS conditions. We present several experimental investigations to characterize plasma spray processes under various pressure conditions. Measured plasma jet properties using a dedicated enthalpy probe system and imaging are combined with IR-pyrometry and velocimetry on the particles (DPV2000) to further improve the understanding of the plasma particle interactions. These results, along with spray deposit characterization, can be used to optimize the coating properties and explore further potential applications.
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