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Abstract: In the field of surface treatment, laser colour marking can be used to produce coloured marks on the surfaces of metals. Laser colour markings can be applied to various materials, but on titanium alloys a wide spectra of vivid colours can be achieved. This study presents an analysis of the corrosion properties of laser treated surfaces that were exposed to aggressive environments. Different samples were prepared with laser light of various power intensities and processing speeds. The samples were prepared on low alloyed Ti. Electrochemical, spectroscopic and microstructural analyses were conducted in order to study the properties of the laser treated surfaces. Corrosion testing showed different effects of laser power and production speed on the properties of the laser treated surfaces. It was shown that a high intensity and slow processing rate affect the surfaces by forming oxides that are relatively stable in a corrosive environment of 0.1 M NaCl. Spectroscopic investigations including scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analyses showed the differences in chemical structure of the surface layer formed after laser treatment. Similarly, microstructural investigations showed different effects on the surface and sub-surface layer of the laser treated samples.
Keywords: Ti alloy, laser treatment, XPS, corrosion
Published in DiRROS: 25.10.2023; Views: 360; Downloads: 141
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Abstract: TiO2+Pt plasmonic solids with 1 wt% Pt and different TiO2 supports (anatase nanoparticles (TNP), polycrystalline nanorods (a-TNR) and single-crystal anatase nanorods (TNR)) were synthesized using the wet impregnation technique and tested as photo, thermal and photothermal catalysts in gas-solid and gas-liquid-solid reactions. Due to the different charges of the TiO2 support surfaces, Pt particles with different sizes, crystallinities and degrees of interaction with the TiO2 supports were formed during the synthesis. The heights of the Schottky barrier (SBH) were 0.38 eV for the a-TNR+Pt, 0.41 eV for the TNP+Pt, and 0.50 eV for the TNR+Pt samples, respectively. The low visible-light-triggered photocatalytic activity of the TNR+Pt catalyst toward the oxidation of water-dissolved bisphenol A (BPA) is attributed to its high SBH and active site deactivation due to the adsorption of BPA and/or BPA oxidation products. The highest photothermal catalytic H2-assisted NO2 reduction rate was expressed by the TNR+Pt catalyst. This can be ascribed to the presence of a narrow particle size distribution of small Pt particles, the absence of the Pt catalysed reduction of the TNR support at higher temperatures, and the lower rate of re-injection of “hot electrons” from the TNR support to the Pt particles.
Keywords: heterogeneous photocatalysis, titanium dioxide, plasmonic noble metal, platinum particles, visible light illumination, Schottky barrier height, bisphenol A, wastewater treatment, NOx abatement, air cleaning, microreactor, thermal catalysis, photothermal catalysis
Published in DiRROS: 23.06.2023; Views: 341; Downloads: 175
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Abstract: The main objective of the EU-funded project mitigating environmentally-assisted cracking through optimisation of surface condition (MEACTOS) was to gain knowledge on the ability of different surface machining procedures to mitigate environmentally-assisted cracking (EAC) in typical light water reactor structural materials and environments. Surfaces of cold-worked (CW) type 316L austenitic stainless steel and nickel-based weld metal Alloy 182 flat tapered tensile specimens were machined using different processes. EAC initiation susceptibility of these specimens was evaluated using constant extension rate tensile (CERT) tests under simulated boiling water reactor (BWR) and pressurized water reactor (PWR) conditions and assessed using constant load experiments. More than a hundred tests were performed covering about 10 years of autoclave testing time. Only minor or no measurable improvements in EAC initiation susceptibility as a function of surface treatments (grinding or advanced machining) compared to the standard industrial face milling were demonstrated. In most cases, the stress thresholds for EAC initiation determined in constant load tests confirmed the trend obtained from CERT tests. This paper summarises the most important results and conclusions concerning the EAC initiation behaviour for the CW 316L and Alloy 182 under reducing PWR and oxidizing BWR conditions.
Keywords: crack initiation, environmentally-assisted cracking, Alloy 182, AISI 304 stainless steel, surface treatment, light water reactor, open access
Published in DiRROS: 30.05.2023; Views: 315; Downloads: 180
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Abstract: The present retrospective study was undertaken to investigate the association of relative dose intensity (RDI) with the outcome of patients with advanced stage Hodgkin lymphoma (HL) receiving ABVD (doxorubicin, bleomycin, vinblastine, dacarbazine) and escalated BEACOPP regimens (bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, prednisone). A total of 114 patients with HL treated between 2004 and 2013 were enrolled for evaluation. The association of variables with overall survival (OS) and progression-free survival (PFS) was analysed using univariate and multivariate Cox proportional hazards models. The median age of patients was 39 years, and the majority were male and had stage IV disease. A total of 54 patients received ABVD and 60 received BEACOPP chemotherapy with 24 and four deaths, respectively. Patients in the BEACOPP group were significantly younger with lower Charlson comorbidity index (CCI) and better performance status in comparison with the ABVD group, making the comparison of groups not possible. In the ABVD group, RDI was not significantly associated with OS (P=0.590) or PFS (P=0.354) in a multivariate model where age was controlled. The low number of events prevented this analysis in the BEACOPP group. The age of patients was strongly associated with both OS and PFS; all statistically significant predictors for OS and PFS from univariate analyses (chemotherapy regimen, CCI, RDI, performance status) lost their effect in multivariate analyses where age was controlled. Based on these observations, it was concluded that RDI was not associated with OS or PFS after age is controlled, neither in all patients combined nor in the ABVD group.
Keywords: Hodgkin lymphoma, chemotherapy, outcome, primary treatment
Published in DiRROS: 23.09.2022; Views: 521; Downloads: 159
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Abstract: Multimodal treatment approaches, such as radio-immunotherapy, necessitate regimen optimization and the investigation of the interactions of different modalities. The aim of this study was two-fold. Firstly, to select the most effective combination of irradiation and the previously developed tumor cell-based vaccine and then to provide insight into the immune response to the selected combinatorial treatment. The study was performed in immunologically different murine tumor models: B16F10 melanoma and CT26 colorectal carcinoma. The most effective combinatorial treatment was selected by comparing three different IR regimens and three different vaccination regimens. We determined the local immune response by investigating immune cell infiltration at the vaccination site and in tumors. Lastly, we determined the systemic immune response by investigating the amount of tumor-specific effector lymphocytes in draining lymph nodes. The selected most effective combinatorial treatment was 5× 5 Gy in combination with concomitant single-dose vaccination (B16F10) or with concomitant multi-dose vaccination (CT26). The combinatorial treatment successfully elicited a local immune response at the vaccination site and in tumors in both tumor models. It also resulted in the highest amount of tumor-specific effector lymphocytes in draining lymph nodes in the B16F10, but not in the CT26 tumor-bearing mice. However, the amount of tumor-specific effector lymphocytes was intrinsically higher in the CT26 than in the B16F10 tumor model. Upon the selection of the most effective combinatorial treatment, we demonstrated that the vaccine elicits an immune response and contributes to the antitumor efficacy of tumor irradiation. However, this interaction is multi-faceted and appears to be dependent on the tumor immunogenicity.
Keywords: experimental oncology, multimodal treatment, radio-imunotherapy
Published in DiRROS: 14.09.2022; Views: 539; Downloads: 282
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