Analysis Of Failure Patterns Research Articles

Photoactivated rose bengal-doped TiO2 nanoparticles modified fifth-generation adhesive on the survival rate of Streptococcus mutants and mechanical properties of tooth-colored restorative material to carious dentin.

Assessment of the antimicrobial, micro tensile bond strength (μTBS), and degree of conversion (DC) of fifth-generation adhesive modified using photoactivated 0.5% rose bengal (RB) and photoactivated RB-doped titanium dioxide nanoparticles (TiO2NPs) in different concentrations (2% and 5%) as compared with the unmodified adhesive bonded to the carious affected dentin (CAD). Forty mandibular molars with caries progression up to the middle third of the dentin, as per the International Caries Detection and Assessment System (ICDAS) score of 4 and 5 were included. Specimens were divided into four groups based on etch and rinse adhesive (ERA) modification group 1: unmodified ERA, group 2: photoactivated 0.5% RB photosensitizer (PS) modified ERA, group 3: photoactivated RB-doped 2 wt% TiO2NPs adhesive, group 4: photoactivated RB-doped 5 wt% TiO2NPs adhesive. Followed by adhesive and composite restoration on the CAD surface. All the specimens were thermocycled and an assessment of μTBS and failure pattern analysis was performed. The antibacterial potency of RB and RB-doped TiO2NPs (2% and 5%) followed by their activation using visible light against Streptococcus mutans (S.mutans) were tested. The survival rate of S.mutans was assessed using the Kruskal-Wallis test. The analysis of μTBS involved the use of ANOVA, followed by a post-hoc Tukey honestly significant difference (HSD) multiple comparisons test. Group 1 (Unmodified ERA) (0.52 ± 0.31 CFU/mL) treated samples unveiled the highest means of bacterial survival and lowest μTBS (11.32 ± 0.63 MPa). Nevertheless, group 4: photoactivated RB-doped 5 wt% TiO2NPs adhesive displayed the lowest outcomes of S.mutans survival (0.11 ± 0.02 CFU/mL) and highest bond strength (18.76 ± 1.45 MPa). The photoactivated RB-doped 2 wt% TiO2NPs in adhesive demonstrated promising enhancements in both μTBS and antibacterial efficacy against S.mutans. However, it is noteworthy that this modification led to a decrease in the DC of the adhesive. RESEARCH HIGHLIGHTS: Unmodified ERA-treated samples unveiled the highest bacterial survival and the lowest μTBS. Photoactivated RB-doped 5 wt% TiO2NPs adhesive displayed the lowest S.mutans survival rate and highest bond strength. DC decreased with an increase in concentration of TiO2.

Failure Pattern and Reliability Analysis of Mobile Biomass Gasifier Engine (Prototype 3) using Weibull Calculation as a Basis for Updating the Preventive Maintenance Activity Schedule

Gasification is a technology that optimistically utilizes biomass to produce syngas (consisting of H2, CO, CO2, CH4) that can be used as an energy source while reducing excess CO2 emissions. However, if there are frequent failures due to unplanned maintenance activities, the engine performance will not be optimal. Therefore, an up-to-date reliability study is needed as a basis for updating preventive maintenance activities to maintain the quality of the engine so that it continues to operate properly and is durable. This research aims to analyze the reliability, unreliability, and availability of the Mobile Biomass Gasifier (Prototype3), as well as study the failure patterns measured using the shape parameter (?) with the Weibull distribution. The focus of this research is on the Suction blower which based on Pareto results is the equipment with the highest failure frequency. The results show that the average reliability is smaller than the failure rate. In addition, the value of the shape parameter (?) > 1, which means that the damage rate increases as the component ages. The implication of this study shows the need to update the preventive maintenance (PM) schedule by considering the addition of new PM activities that are in accordance with the duration of the life of the components that cause machine damage.

421: Post-Adjuvant Radiation Failure Pattern Analysis in Bucco-Alveolar complex carcinoma by Focal volume

421: Post-Adjuvant Radiation Failure Pattern Analysis in Bucco-Alveolar complex carcinoma by Focal volume

Real-World Patterns and Economic Burden Associated With Treatment Failure With Advanced Therapies in Patients With Moderate-to-Severe Ulcerative Colitis

Abstract Background Some patients lose response during treatment for moderate-to-severe ulcerative colitis (UC). We aimed to characterize real-world treatment failure patterns and associated economic burdens during use of first-line advanced therapies for UC. Methods IBM MarketScan Commercial and Medicare Supplemental Databases were used to identify adults initiating ≥ 1 advanced therapy for UC (January 1, 2010–September 30, 2019). Treatment failure was defined as augmentation with non-advanced therapy, discontinuation, dose escalation/interval shortening, failure to taper corticosteroids, UC-related surgery, or UC-related urgent care ≤ 12 months after treatment initiation. The index date was the date of treatment failure (treatment failure cohort) or 12 months after treatment initiation (persistent cohort). Treatment failure rates were assessed using Kaplan–Meier analyses. All-cause and UC-related healthcare resource utilization (HCRU) and costs 12 months post-index were also assessed. Results Analysis of treatment failure patterns included data from 6745 patients; HCRU and cost analyses included data from 5302 patients (treatment failure cohort, n = 4295; persistent cohort, n = 1007). In the overall population, 75% experienced treatment failure within the first 12 months (median: 5.1 months). Augmentation with non-advanced therapy (39%) was the most common first treatment failure event. The treatment failure cohort had significantly (P < .001) higher mean costs than the persistent cohort (all-cause, $74 995 vs $56 169; UC-related, $57 096 vs $47 347) mainly attributed to inpatient admissions and outpatient visits. Dose escalation/interval shortening accounted for the highest total costs ($101 668) across treatment failure events. Conclusions Advanced therapies for moderate-to-severe UC are associated with high rates of treatment failure and significant economic burden. More efficacious and durable treatments are needed.

Pattern analysis of auto parts failures in the after-sales service network; an interconnected approach of association rules mining and Bayesian networks in the automotive industry

PurposeWarranty-based big data analysis has attracted a great deal of attention because of its key capabilities and role in improving product quality while minimizing costs. Information and details about particular parts (components) repair and replacement during the warranty term, usually stored in the after-sales service database, can be used to solve problems in a variety of sectors. Due to the small number of studies related to the complete analysis of parts failure patterns in the automotive industry in the literature, this paper focuses on discovering and assessing the impact of lesser-studied factors on the failure of auto parts in the warranty period from the after-sales data of an automotive manufacturer.Design/methodology/approachThe interconnected method used in this study for analyzing failure patterns is formed by combining association rules (AR) mining and Bayesian networks (BNs).FindingsThis research utilized AR analysis to extract valuable information from warranty data, exploring the relationship between component failure, time and location. Additionally, BNs were employed to investigate other potential factors influencing component failure, which could not be identified using Association Rules alone. This approach provided a more comprehensive evaluation of the data and valuable insights for decision-making in relevant industries.Originality/valueThis study's findings are believed to be practical in achieving a better dissection and providing a comprehensive package that can be utilized to increase component quality and overcome cross-sectional solutions. The integration of these methods allowed for a wider exploration of potential factors influencing component failure, enhancing the validity and depth of the research findings.

Could Residual Disease Irradiation be Better than Involved Field Irradiation for Limited-Stage Small Cell Lung Cancer? A Failure Pattern Analysis

For limited-stage small cell lung cancer (LS-SCLC), the thoracic radiotherapy (TRT) plays a vital role. Previous clinical research showed that for the TRT could be limited to the postchemotherapy tumor volume and the positive prechemotherapy lymph node regions. Involved field irradiation (IFI) could be routinely applied. However, the optimum radiation field design remains controversial. In the present study, we retrospectively analyzed the patterns of failure in LS-SCLC patients receiving residual disease irradiation (RDI) in radiotherapy. A total of 47 patients with LS-SCLC treated with RDI with sequent or concurrent chemotherapy were enrolled in this study. The gross tumor volume (GTV) defined as residual volumes of positive node and primary tumor of the post-chemotherapy. The clinical target volume (CTV) included GTV with a margin 0.5 cm. Planning target volume (PTV) involved CTV with a margin 0.5 cm. RFI consisted of 1.5 grays (Gy) twice daily in 30 fractions up to a total dose of 45 Gy or 2.0 Gy daily up to 60 Gy. Treatment failures were divided into local and distant failures, and local recurrences were classified into inside RDI(IN-RDI), between RDI and IFI(RDI-IFI), and outside IFI(OUT-IFI). Among the 46 patients with detailed follow-up data for recurrences, 36 (78.3%) experienced recurrences, with 16 (34.8%) being local recurrence, and 29 (63.0%) being distant failure. For the 16 patients with local recurrences, 10, 5, and 1 were IN-RDI, OUT-IFI, and RDI-IFI recurrences, respectively. Residual disease irradiation (RDI) is feasible for LS-SCLC treated with sequent or concurrent chemotherapy and does not compromise failure inside the involved region.

AI Model Factory: Scaling AI for Industry 4.0 Applications

This demo paper discusses a scalable platform for emerging Data-Driven AI Applications targeted toward predictive maintenance solutions. We propose a common AI software architecture stack for building diverse AI Applications such as Anomaly Detection, Failure Pattern Analysis, Asset Health Forecasting, etc. for more than a 100K industrial assets of similar class. As a part of the AI system demonstration, we have identified the following three key topics for discussion: Scaling model training across multiple assets, Joint execution of multiple AI applications; and Bridge the gap between current open source software tools and the emerging need for AI Applications. To demonstrate the benefits, AI Model Factory has been tested to build the models for various industrial assets such as Wind turbines, Oil wells, etc. The system is deployed on API Hub for demonstration.

Etch-and-rinse versus self-etch strategy of a universal adhesive in different application methods at the bonding interface of fiber post cementation.

To evaluate the effect of etch-and-rinse (ER) versus self-etch (SE) strategies of a universal adhesive applied with a manual brush (MB) or rotary brush (RB) on the bonding interface of fiber post cementation. Forty bovine incisor roots were prepared and divided into four groups according to the methods of application and strategy of universal adhesive use (MB-ER, RB-ER, MB-SE and RB-SE). After 6 months, specimens from different thirds of the post space were evaluated of push-out strength, analysis of adhesive failure patterns, and extent of tags. The RB-ER and RB-SE groups showed the highest bond strength values in the cervical and middle thirds of the post space. Cohesive adhesive failure had the highest incidence in the different thirds of the post space in the ER strategy, regardless of the adhesive application method. The RB-ER group showed the highest tag extensions. The protocols of universal adhesive application with RB provided the greater bond strength, but only the ER strategy favored the formation of a greater extension of tags at the adhesive interface. The application of universal adhesive with RB into the post space increases the strength of the post-cemented fiber bond.

Influence of dynamic disturbed frequency on rock failure characteristics under triaxial cyclic and multistage unloading confining pressure loads

AbstractThis work aims to reveal the influence of disturbed frequency on the failure of deeply buried granodiorite under triaxial cyclic and multistage unloading confining pressure (CMSUCP) conditions. Testing results show that volumetric deformation is obviously influenced by the disturbed frequency. The volumetric strain was characterized as an early dilatancy‐dominant behavior for a sample under low disturbed frequency. The deformation development at the unloading confining pressure stage is larger than at the cyclic loading stage. The hysteresis damping decreases with increasing disturbed frequency indicating that much energy loss occurs due to damage accumulation. A first slow followed by accelerated damage propagation is expressed using a radial irreversible strain‐based damage evolution model. Macro‐meso failure pattern analysis reveals that rock dominant failure changes from mixed tensile‐shear failure to pure shear failure and a transmission from softening to hardening characteristics. It is suggested that failure develops fully for rock subjected to low disturbed frequency.

Effect of different irrigants on the push-out bond strength of biodentine and TheraCal LC when used for perforation repair in simulated condition.

Perforation repair materials should have excellent sealing ability and dislodgement resistance. While several materials have been employed for perforation repair, newer calcium-silicate materials, such as Biodentine and TheraCal LC, have shown promising outcomes. This study aimed to evaluate the effect of different irrigants on the dislodgement resistance of Biodentine and TheraCal LC when used for perforation repair in simulated conditions. 3% sodium hypochlorite, 2% chlorhexidine gluconate, and 17% EDTA were evaluated for their effect on the dislodgement resistance of Biodentine and TheraCal LC. 48 permanent mandibular molars were selected for the study. The samples were divided into two groups: Group I - Biodentine and Group II - TheraCal LC, with 24 samples each. The mean dislodgement resistance and standard deviation of Group I (Biodentine) and Group II (TheraCal LC) were compared and Failure pattern analysis was done. Biodentine showed a significant decrease in push-out bond strength after contact with 3% NaOCl, 2% CHX, and 17% EDTA whereas, TheraCal LC showed no significant decrease in push-out bond strength after exposure to 3% NaOCl, 2% CHX, and 17% EDTA. Overall, TheraCal LC can be considered good perforation repair material with excellent physical and biological properties.

The efficacy of thoracic radiotherapy in extensive stage small cell lung cancer with baseline brain metastases: a multi-institutional retrospective cohort study.

Thoracic radiotherapy (TRT) had been shown to improve overall survival (OS) in extensive-stage small cell lung cancer (ES-SCLC) patients. However, approximately one fourth of SCLC harbored baseline brain metastases (BMs) and were excluded from previous TRT trials. Thus, the role of TRT in this sub-cohort of ES-SCLC requires elucidation. In this study, we evaluated the efficacy of TRT in ES-SCLC patients with clinically controlled baseline BMs. In this retrospective, multi-institutional cohort study, 49 patients fully staged as ES-SCLC with baseline BM, had their disease controlled at all sites with no BM symptoms for three months since treatment initiation were included. The patients were allocated to TRT or no-TRT groups according to whether they received consolidative TRT before progression. Their baseline characteristics were compared using the χ2 test. OS was selected as the primary observational endpoint. Survival and the incidence of cumulative progression between the groups were compared using log-rank analysis, and the interaction between TRT and selected factors was assessed via Cox proportional hazard analysis. Subgroup analysis was performed in oligo-metastasis patients (defined as five or fewer metastatic lesions in two or fewer organs). Seventeen (34.7%) patients received TRT, with a median dose of 54 Gy. The failure pattern analysis revealed initial intrathoracic progression in 31.3% and 66.7% of patients in the TRT no-TRT groups, respectively. Also, the TRT group had a significantly longer OS than the no-TRT group [hazard ratio (HR) 0.426, P=0.011]. Clinical covariates including age, gender, performance status, smoking, metastatic state, response after chemotherapy, and TRT, were included in multivariate regression analysis. TRT remained significantly correlated with better OS (HR 0.430, P=0.029). Twenty-three (46.9%) patients had oligo-metastasis at baseline. Subgroup analyses showed that TRT was significantly correlated with better OS in oligo-metastatic patients but not in non-oligo metastatic patients. TRT improved the prognosis of select ES-SCLC patients with baseline BMs and should be considered in this sub-cohort, which has not been covered by previous randomized trials.

Detailed analysis of failure patterns using deformable image registration in hypopharyngeal cancer patients treated with sequential boost intensity-modulated radiotherapy.

Sequential boost intensity-modulated radiotherapy (SQB-IMRT) uses two different planning CTs (pCTs) and treatment plans. SQB-IMRT is a form of adaptive radiotherapy that allows for responses to changes in the shape of the tumour and organs at risk (OAR). On the other hand, dose accumulation with the two plans can be difficult to evaluate. The purpose of this study was to analyse patterns of loco-regional failure using deformable image registration (DIR) in hypopharyngeal cancer patients treated with SQB-IMRT. Between 2013 and 2019, 102 patients with hypopharyngeal cancer were treated with definitive SQB-IMRT at our institution. Dose accumulation with the 1st and 2nd plans was performed, and the dose to the loco-regional recurrent tumour volume was calculated using the DIR workflow. Failure was classified as follows: (i) in-field (≥95% of the recurrent tumour volume received 95% of the prescribed dose); (ii) marginal (20-95%); or (iii) out-of-field (<20%). After a median follow-up period of 25months, loco-regional failure occurred in 34 patients. Dose-volume histogram analysis showed that all loco-regional failures occurred in the field within 95% of the prescribed dose, with no marginal or out-of-field recurrences observed. The dosimetric analysis using DIR showed that all loco-regional failures were within the high-dose region. More aggressive treatment may be required for gross tumours.

Distinct Failure Patterns in Hypopharyngeal Cancer Patients Receiving Surgery-Based Versus Radiation-Based Treatment

BackgroundTo cure advanced hypopharyngeal squamous cell carcinoma (HPSCC), primary operation followed by adjuvant (chemo-)radiotherapy (OP-CRT) or definitive chemoradiation (CCRT) are the two primary options. This study aimed to compare the failure patterns and long-term survival outcomes of HPSCC patients treated with these two strategies.Patients and MethodsFrom 2007 to 2015, 198 pathologically confirmed HPSCC patients receiving either OP-CRT or CCRT were retrospectively reviewed. Failure patterns and survival outcomes stratified by the 7th American Joint Committee on Cancer staging system and treatment modalities were compared.ResultsOne hundred and eighty-nine patients (95.4%) were stage III/IV and 62 patients (31.3%) received OP-CRT. Median follow-up duration was 4.9 years. Compared with CCRT, OP-CRT provided better 3-year local relapse-free survival for T3 (93 vs 48%, p < 0.0001), T4a (88 vs 37%, p = 0.0005) and better 3-year regional relapse-free survival for N2b+2c (93 vs 60%, p < 0.0001). Of note, for stage IVA subjects, OP-CRT provided better 3-year loco-regional relapse-free survival (85 vs 37%, p < 0.0001), marginal poor 3-year distant metastasis-free survival (62 vs 79%, p = 0.06), but comparable 3-year OS (52 vs 44%, p = 0.37) and 5-year OS (44 vs 31%, p = 0.15) compared with CCRT.ConclusionsFor patients with advanced HPSCC, although OP-CRT and CCRT provided similar overall survival, failure patterns were distinct. OP-CRT provided better loco-regional control but was more likely to encounter distant metastases than CCRT. The detailed analysis of failure patterns will pave the way to improve this devastating disease.

The impact of provisional intraradicular retainers cementation with temporary methacrylate-based resin in the bond strength of glass fiber posts to root dentin

Chemical composition of temporary cements interferes in the bond strength and quality of the bond interface of glass fiber posts to root dentin. The aim of the present study was to evaluate the influence of different temporary cements on the bond strength of fiberglass posts and resin cement. Thirty-two maxillary central incisor roots were standardized at 15 mm length. The root canals were prepared with Reciproc R50 and filled with a R50 single cone and AH Plus. Ten mm of filling material was removed with a heated Schilder condenser, leaving 5 mm of apical filling material. The roots were randomly distributed into 4 groups (n = 8). In the control group, the root canal was prepared with a standard drill according to the post diameter (DC #1, FGM, Joinville, Brazil), irrigated with 5 mL of distilled water and immediately received the fiberglass post cemented with self-adhesive resin cement. For the other groups, cores were made with temporary intraradicular retainers cemented with different temporary cements: methacrylate-based resin (Bifix Temp - Voco), calcium hydroxide-based (Provicol - Voco) and zinc oxide-based – eugenol-free (Relyx Temp NE - 3M). After 7 days, mechanical removal of the temporary retainers, preparation, irrigation of the root canal and cementation of the fiberglass post were performed, following the same protocol that had been performed in the control group. The roots were sectioned to obtain 3 slices per root third. The most cervical section of each third was used for the push-out test and failure pattern analysis, while the most apical section was subjected to analysis of the adhesive interface by scanning electron microscopy (SEM). The BS data were compared between groups using the two-way ANOVA and Tukey post-test. The failure pattern results were expressed in percentage and compared between groups using the chi-square test and the material adaptation data at the bond interface were evaluated using the Kruskal-Wallis and Dwass-Steel-Critchlow-Fligner tests. The results showed higher BS in the cervical third, with a higher value in the control group (10.8 ± 0.94) and Bifix Temp group (9.78 ± 0.71), with no statistically significant difference between these groups (P > .05). The middle and apical thirds showed no statistically significant difference (P > .05). As regards the type of failure, a higher percentage of mixed adhesive failures was observed for all groups. Analysis of the adhesive interface by SEM showed that the temporary cement Bifix Temp showed greater adaptation at the bond interface. It was concluded that the methacrylate-based resin temporary cement showed the highest bond strength values and best adaptation to root dentin than the zinc oxide-based and calcium hydroxide-based temporary cements.

Reliability Analysis of Keith Centrifuge at a Meat Processing Plant in Windhoek, Namibia

Critical equipment failures in a meat processing plant can shut down the business unit, resulting in a loss of output and financial loss. Furthermore, many stakeholders face risks because of equipment failures. The purpose of this study is to model the failures of the critical equipment which will in turn aid in the analysis of failure patterns and the production of various reliability estimations to prevent such losses. In a meat processing plant, the blood centrifuge is important equipment as failure will render the plant non-operational. This case study conducted the failure analyses of the ‘Keith' centrifuge at the meat processing plant in Windhoek, Namibia. Both parametric and nonparametric models were conducted with the help of computer software. In addition, sensitivity analysis was carried out on both models to improve the reliability of the equipment. The preventative maintenance model was also constructed and tested in the meat processing plant, and it provided good results.

Analysis of failure pattern in cut slopes of bedded sandstone: a case study

Analysis of failure pattern in cut slopes of bedded sandstone: a case study

Ways to unravel the clinical potential of carbon ions for head and neck cancer reirradiation: dosimetric comparison and local failure pattern analysis as part of the prospective randomized CARE trial

BackgroundCarbon ion radiotherapy (CIRT) yields biophysical advantages compared to photons but randomized studies for the reirradiation setting are pending. The aim of the current project was to evaluate potential clinical benefits and drawbacks of CIRT compared to volumetric modulated arc therapy (VMAT) in recurrent head and neck cancer.MethodsDose-volume parameters and local failure patterns of CIRT compared to VMAT were evaluate in 16 patients from the randomized CARE trial on head and neck cancer reirradiation.ResultsDespite an increased target dose, CIRT resulted in significantly reduced organ at risk (OAR) dose across all patients (− 8.7% Dmean). The dose-volume benefits were most pronounced in the brainstem (− 20.7% Dmax) and the optic chiasma (− 13.0% Dmax). The most frequent local failure was type E (extraneous; 50%), followed type B (peripheral; 33%) and type A (central; 17%). In one patient with type A biological and/or dosimetric failure after CIRT, mMKM dose recalculation revealed reduced target coverage.ConclusionsCIRT resulted in highly improved critical OAR sparing compared to VMAT across all head and neck cancer reirradiation scenarios despite an increased prescription dose. Local failure pattern analysis revealed further potential CIRT specific clinical benefits and potential pitfalls with regard to image-guidance and biological dose-optimization.

Experimental Investigation of Shale Tensile Failure under Thermally Conditioned Linear Fracturing Fluid (LFF) System and Reservoir Temperature Controlled Conditions.

Linear fracturing fluid (LFF) provides viscosity driven benefits of proppant suspensibility and fluid loss control, and with the use of a breaker agent, flowback recovery can be greatly enhanced. Shale tensile strength is critical in the prediction of fracture initiation and propagation, but its behavior under the interaction with LFF at reservoir temperature conditions remains poorly understood. This necessitated an in-depth investigation into the tensile strengths of Eagle Ford and Wolfcamp shales under thermally conditioned LFF and reservoir temperature controlled conditions. Brazilian Indirect Tensile Strength (BITS) testing was carried out for the quantitative evaluation of shale tensile strength, followed by extensive failure pattern classifications and surface crack length analysis. The thermally conditioned LFF saturation of shale samples led to average tensile strength (ATS) increases ranging from 26.33–51.33% for Wolfcamp. Then, for the Eagle Ford samples, ATS increases of 3.94 and 6.79% and decreases of 3.13 and 15.35% were recorded. The exposure of the samples to the temperature condition of 90 °C resulted in ATS increases of 24.46 and 33.78% for Eagle Ford and Wolfcamp shales, respectively. Then, for samples exposed to 220 °C, ATS decreases of 6.11 and 5.32% were respectively recorded for Eagle Ford and Wolfcamp shales. The experimental results of this research will facilitate models’ development towards tensile strength predictions and failure pattern analysis and quantifications in the LFF driven hydraulic fracturing of shale gas reservoirs.

Assessment of stress-strain constitutive models and failure models on the shock tube based impact forming of AA 5052-H32 sheet

The present study focuses on the numerical and experimental investigation of the shock tube based forming of AA 5052-H32 sheet using a rigid nylon striker. During the shock tube impact forming, the pressure developed and the velocity of the striker are modelled in two stages, i.e., incorporating pressure in the first stage and striker displacement in the second stage during finite element simulation using DEFORM 3D. The main aim of this study is to understand the effect of different flow stress models and failure models on the forming outputs such as dome height, velocity of the sheet, effective strain distribution, and failure modes. A new strategy is followed to evaluate the rate-dependent mechanical properties by the tensile test of the sheet deformed using the shock tube. The forming outputs predicted by incorporating these properties have an acceptable agreement with the experimental data. Out of all flow stress models, modified Johnson-Cook model shows better flow stress predictability because of the inclusion of nonlinear strain rate sensitivity terms. The failure pattern analysis shows both Johnson-Cook model and Modified Johnson-Cook model have a fair agreement with experimental results. Failure strain and petal formation predicted by Brozzo failure model and Freudenthal failure model match acceptably with the experimental results. SEM images confirm deeper and larger parabolic dimples on the fracture surface of shock tube-based deformed sheet, indicating enhanced formability as compared to the sheet formed by quasi-static deformation.

Effect of different cleaning methods after surface treatment of dental ceramics on the surface characteristics and adhesion to resin-based luting agents

The aim of this study was to assess the efficacy of cleaning methods after the surface treatment of dental ceramics. Ceramic slabs (zirconia – Yz; lithium disilicate-reinforced glass – Ld; and porcelain – Pc), were submitted to different surface treatments (air abrasion for Yz and hydrofluoric acid etching for Ld and Pc), and after, six cleaning methods were tested: DW – distilled water for 60 s; AL – 70% alcohol for 60 s + DW; UDW – ultrasonic bath with distilled water for 60 s; UAL – ultrasonic bath with 70% alcohol for 60 s + DW; IVC – ivoclean for 20 s + DW; PAC – 37% phosphoric acid for 20 s + DW. Microshear bond strength to luting agent was tested after 24 h (baseline) or 6 months storage (aged) in water at 37 °C. Complementary analysis of failure pattern, surface topography and composition, and contact angle measurements were executed. The cleaning methods promoted similar bond strength for Ld and Pc, regardless of the condition (baseline and aged) and for Yz after aging. DW, AL, and PAC decreased the contact angle for Yz, while UAL decreased for Ld. Pc presented a higher wettability with UDW, UAL, and PAC. The use of IVC and PAC resulted in precipitates in the Pc surface. For Yz, more air-abrasion remnants were observed using DW; for both Ld and Pc, a higher presence of fluorine was observed in groups treated with IVC. Despite differences in surface composition, topography and contact angle measurements, after aging the bond strength to the tested ceramic materials was similar regardless of the different cleaning methods.