Design of Comb Crack Resistant Milling Inserts: A Comparison of Stresses, Crack Propagation, and Deformation Behavior between Ti(C,N)/α-Al2O3 and Zr(C,N)/α-Al2O3 CVD Coatings

Investigations on comb crack resistance of milling inserts coated with chemical vapor deposition (CVD) Ti(C,N)/α-Al2O3 and Zr(C,N)/α-Al2O3 showed a distinct wear evolution in both systems. Wear studies revealed that the appearance of comb cracks is connected to the initial CVD cooling crack network. Micropillar compression tests indicated a brittle intergranular fracture mechanism for the Ti(C,N) layer and a transgranular fracture accompanied with signs of plastic deformation for the Zr(C,N) coating. Additionally, for the Zr(C,N) based system, a compressive stress condition in the temperature range of interest (200–600 ◦C) was determined by in-situ synchrotron X-ray diffraction. The set of residual compressive stresses together with the ability of the Zr(C,N) layer to deform plastically are key features that explain the enhanced resistance to comb crack wear of the Zr(C,N) based system in milling of cast iron

Reabilitação estética e funcional de paciente com erosão ácida: relato de caso / Aesthetic and functional rehabilitation of a patient with acid erosion: case report

A erosão dentária é uma doença multifatorial e influenciada por hábitos pessoais e estilos de vida.  Ela é caracterizada pela perda progressiva de tecido dentário devido a processos químicos sem envolvimento bacteriano. Os fatores desencadeantes desta alteração podem ser provenientes de fontes extrínsecas (frutas e bebidas ácidas e comprimidos de vitamina C) ou intrínsecas (vômitos recorrentes resultantes de desordens psicológicas, fisiológicas ou alimentares). O tratamento da erosão inicia-se pelo diagnóstico e tratamento médico e, após seu controle, a reabilitação dos dentes afetados. O objetivo deste trabalho é apresentar um caso de erosão dental generalizada onde foi realizado a reabilitação estética e funcional de todos os elementos dentários acometidos com resina composta. O caso está em acompanhamento odontológico há quatro meses e a paciente apresentou melhora perceptível da saúde bucal e estética, aumento da autoestima e satisfação com o resultado

Effect of synbiotic supplementation in children and adolescents with cystic fibrosis: a randomized controlled clinical trial

BACKGROUND/OBJECTIVES:Cystic fibrosis (CF) is characterized by excessive activation of immune processes. The aim of this study was to evaluate the effect of synbiotic supplementation on the inflammatory response in children/adolescents with CF. SUBJECTS/METHODS:A randomized, placebo-controlled, double-blind, clinical-trial was conducted with control group (CG, n = 17), placebo-CF-group (PCFG, n = 19), synbiotic CF-group (SCFG, n = 22), PCFG negative (n = 8) and positive (n = 11) bacteriology, and SCFG negative (n = 12) and positive (n = 10) bacteriology. Markers of lung function (FEV1), nutritional status [body mass index-for age (BMI/A), height-for-age (H/A), weight-for-age (W/A), upper-arm fat area (UFA), upper-arm muscle area (UMA), body fat (%BF)], and inflammation [interleukin (IL)-12, tumor necrosis factor-alpha (TNF-α), IL-10, IL-6, IL-1β, IL-8, myeloperoxidase (MPO), nitric oxide metabolites (NOx)] were evaluated before and after 90-day of supplementation with a synbiotic. RESULTS:No significance difference was found between the baseline and end evaluations of FEV1 and nutricional status markers. A significant interaction (time vs. group) was found for IL-12 (p = 0.010) and myeloperoxidase (p = 0.036) between PCFG and SCFG, however, the difference was not maintained after assessing the groups individually. NOx diminished significantly after supplementation in the SCFG (p = 0.030). In the SCFG with positive bacteriology, reductions were found in IL-6 (p = 0.033) and IL-8 (p = 0.009) after supplementation. CONCLUSIONS: Synbiotic supplementation shown promise at diminishing the pro-inflammatory markers IL-6, IL-8 in the SCFG with positive bacteriology and NOx in the SCFG in children/adolescents with CF

Design of Comb Crack Resistant Milling Inserts: A Comparison of Stresses, Crack Propagation, and Deformation Behavior between Ti(C,N)/α-Al2O3 and Zr(C,N)/α-Al2O3 CVD Coatings

Investigations on comb crack resistance of milling inserts coated with chemical vapor deposition (CVD) Ti(C,N)/α-Al2O3 and Zr(C,N)/α-Al2O3 showed a distinct wear evolution in both systems. Wear studies revealed that the appearance of comb cracks is connected to the initial CVD cooling crack network. Micropillar compression tests indicated a brittle intergranular fracture mechanism for the Ti(C,N) layer and a transgranular fracture accompanied with signs of plastic deformation for the Zr(C,N) coating. Additionally, for the Zr(C,N) based system, a compressive stress condition in the temperature range of interest (200–600 °C) was determined by in-situ synchrotron X-ray diffraction. The set of residual compressive stresses together with the ability of the Zr(C,N) layer to deform plastically are key features that explain the enhanced resistance to comb crack wear of the Zr(C,N) based system in milling of cast iron

Wear behavior of Ti1-xAlxN-based coatings during turning

Ti1-xAlxN coatings are extensively used on cutting tools used for metal cutting. In this thesis, the wear behavior of TiN, TiAlN with different Al-content, and TiAlWN and TiAlMoN coatings is investigated after turning, using electron microscopy and X-ray absorption spectroscopy techniques. An in operando study using high-energy X-ray diffraction during turning is also carried out, to understand the strain and phase evolution of TiAlN coatings during machining.  The main wear mechanisms when cutting stainless steel 316L with cutting speeds from 60 m/min up to 220 m/min are investigated. The results show a difference in wear behavior with cutting speed. At low cutting speeds, adhesive wear is the main mechanism that generates coating failure, causing fracture of the coating. The higher Al-content coatings (x ≥ 0.53) perform better compared to lower Al-content coatings, likely due to a better fracture resistance. At higher cutting speeds, 220 m/min, crater wear due to abrasive wear and chemical reactions between coating and workpiece material occurs. In this case, the high temperatures achieved during turning results in formation of hexagonal (h)-AlN in Ti0.38Al0.62N coatings, which lowers their wear resistance. For TiAlMoN and TiAlWN, an improved wear behavior is observed compared to pure TiAlN, because it retards spinodal decomposition and the subsequent formation of h-AlN.  Investigations of the sliding area using TEM, EDS and XANES spectra from the Ti 1s-edge reveals that there are differences in level of spinodal decomposition, thus differences in temperature, in different regions of the tool.  During in operando orthogonal turning of alloy steel, spinodal decomposition was observed to take place after only 10 s of turning for the highest Al-content coatings. Decomposition occurs where the temperature of the rake face is the highest.  In summary, the results achieved lead to a better understanding of the interactions between tool and workpiece material and the different wear mechanisms which may expand the application envelope for these coatings

Estudo in situ da evolução de tensões residuais em multicamadas de CVD em Zr(C,N)/α-Al2O3 e Zr(C,N)/κ-Al2O3 durante ciclos térmicos

The present work analyses the residual stresses of thin films in coated cutting tools used in milling applications. Typical wear limitation is the formation of comb cracks, which lead to chipping and failure of the tools. The resistance to comb cracks depends on the ability of the coated tools to reduce the formation of thermo-mechanical cracks, which are originated in the coating and propagate into the carbide. By adjusting the residual stress condition of the coating/carbide substrate (which depends among others on the coefficient of thermal expansion of the layers, the processing method as well as the pre-or post-treatment) the resistance to comb crack failure can be improved. The Ti(C,N)/α-Al2O3 system is the most common used in the industry. Recently, an alternative coating with improved comb crack resistance based on Zr(C,N)/α-Al2O3 has been developed. In some applications the use of κ-Al2O3 is of advantage. In this work the residual stress analyses of Zr(C,N)/κ-Al2O3 and Zr(C,N)/α-Al2O3 coatings produced by (CVD) were carried out using Energy Dispersive X-ray diffraction. Furthermore, the residual stresses were analyzed \"in situ\" at cycling temperature conditions ranging from RT to 800 ºC in order to verify the influence of the different systems on the residual stress evolution and behaviour of the composites. In addition, the influence of micro-top-blasting on the residual stress of the thin films was investigated. It was observed that both the Zr(C,N)/κ-Al2O3 and Zr(C,N)/α-Al2O3 systems present similar residual stress cycling behaviour. The effect of the top-blasting process is confined to the α-Al2O3 layer, which develops high compressive residual stresses. The results of this work provides valuable information for the design of novel coating systems with enhanced resistance to comb cracks.O presente trabalho trata da análise de tensões residuais de filmes finos em ferramentas de corte revestidas utilizadas em aplicações de fresamento. Uma limitação de desgaste típica é a formação de trincas na forma de pente, que levam ao lascamento e falha das ferramentas. A resistência às trincas depende da capacidade das ferramentas revestidas de reduzir a formação destas, que são originadas no revestimento e se propagam para dentro do carbeto. Ajustando a condição de tensão residual do revestimento/carbeto cementado (que depende, entre outros, do CTE das camadas, o método de processamento, o pré ou pós-tratamento) a resistência à falha pode ser melhorada. O sistema Ti(C,N)/α-Al2O3 é o mais utilizado na indústria. Recentemente, um revestimento alternativo com resistência melhorada a estas trincas baseado em Zr(C,N)/α-Al2O3 foi desenvolvido. Em algumas aplicações, o uso de κ-Al2O3 é vantajoso. Neste trabalho, as análises de tensões residuais de revestimentos de Zr(C,N)/κ-Al2O3 e Zr(C,N)/α-Al2O3 produzidos por (CVD) foram realizadas utilizando difração de raios X por dispersão de energia. As tensões residuais foram analisadas \"in situ\" nas condições de temperatura do ciclo variando de RT a 800 ºC, a fim de verificar a influência dos diferentes sistemas na evolução e no comportamento dos tensões residuais dos compósitos. Além disso, a influência do microjateamento na tensão residual dos filmes finos foi investigada. Observou-se que ambos os sistemas Zr(C,N)/κ-Al2O3 e Zr(C,N)/α-Al2O3 apresentam comportamento cíclico semelhante de tensão residual. O efeito do processo de jateamento está confinado à camada α-Al2O3, que desenvolve altas tensões residuais de compressão. Os resultados deste trabalho fornecem informações valiosas para o projeto de novos sistemas de revestimento com maior resistência às trincas

Effects of platelet-rich plasma on lateral epicondylitis of the elbow: prospective randomized controlled trial

ABSTRACT OBJECTIVE: To evaluate the effects of platelet-rich plasma (PRP) infiltration in patients with lateral epicondylitis of the elbow, through analysis of the Disabilities of the Arm, Shoulder and Hand (DASH) and Patient-Rated Tennis Elbow Evaluation (PRTEE) questionnaires. METHODS: Sixty patients with lateral epicondylitis of the elbow were prospectively randomized and evaluated after receiving infiltration of three milliliters of PRP, or 0.5% neocaine, or dexamethasone. For the scoring process, the patients were asked to fill out the DASH and PRTEE questionnaires on three occasions: on the day of infiltration and 90 and 180 days afterwards. RESULTS: Around 81.7% of the patients who underwent the treatment presented some improvement of the symptoms. The statistical tests showed that there was evidence that the cure rate was unrelated to the substance applied (p = 0.62). There was also intersection between the confidence intervals of each group, thus demonstrating that the proportions of patients whose symptoms improved were similar in all the groups. CONCLUSION: At a significance level of 5%, there was no evidence that one treatment was more effective than another, when assessed using the DASH and PRTEE questionnaires

Crater wear mechanism of TiAlN coatings during high-speed metal turning

The influence of the aluminium content (x) on crater wear mechanisms of Ti1-xAlxN coated WC-Co inserts in highspeed turning of 316L stainless steel was investigated. Electron microscopy and energy dispersive X-ray spectroscopy were used to characterize the wear behaviour. Ti1-xAlxN coatings with x &amp;lt;= 0.53 showed, after 1/3 of the tool life, a thick adhered layer composed of oxides and metallic species from the steel, and no diffusion of workpiece material into the coating. These coatings presented the best wear resistance and least abrasive wear. The high aluminium content Ti0.38Al0.62N coating showed the worst crater wear resistance. This is assigned to interdiffusion of workpiece elements and oxygen into the coating as a consequence of spinodal decomposition of the cubic TiAlN-phase, resulting in more severe abrasive wear.Funding Agencies|VINNOVAVinnova [2016-05156]; Swedish government strategic research area grant AFM -SFO MatLiU [2009-00971]</p