Maximum Defect Research Articles

Optimized cartilage visualization using 7-T sodium ((23)Na) imaging after patella dislocation.

Retropatellar cartilage lesions often occur in the course of recurrent patella dislocation. Aim of this study was to develop a more detailed method for examining cartilage tissue, in order to reduce patient discomfort and time of care. For detailed diagnosing, a 7-T MRI of the knee joint and patella was performed in nine patients, with mean age of 26.4years, after patella dislocation to measure the cartilage content in three different regions of interest of the patella. Axial sodium ((23)Na) images were derived from an optimized 3D GRE sequence on a 7-T MR scanner. Morphological cartilage grading was performed, and sodium signal-to-noise ratio (SNR) values were calculated. Mean global sodium values and SNR were compared between patients and volunteers. Two out of nine patients showed a maximum cartilage defect of International Cartilage Repair Society (ICRS) grade 3, three of grade 2, three of grade 1, and one patient showed no cartilage defect. The mean SNR in sodium images for cartilage was 13.4±2.5 in patients and 14.6±3.7 in volunteers (n.s.). A significant negative correlation between age and global sodium SNR for cartilage was found in the medial facet (R=-0.512; R (2)=0.26; p=0.030). Mixed-model ANOVA yielded a marked decrease of the sodium SNR, with increasing grade of cartilage lesions (p<0.001). Utilization of the (23)Na MR imaging will make earlier detection of alterations to the patella cartilage after dislocation possible and will help prevent subsequent disease due to start adequate therapy earlier in the rehabilitation process. II.

Influence of case-carburizing and micro-defect on competing failure behaviors of Ni–Cr–W steel under gigacycle fatigue

Axial loading test was performed to investigate the influence of case-carburizing and micro-defect on competing failure behaviors of Ni–Cr–W Steel under gigacycle fatigue. The interior failures induced from inclusion and microstructural inhomogeneity become the predominant failure mode in the life regime beyond 105 cycles. The case-carburizing has no effect on the fatigue strength with interior failure. Compared with the lower limit values of experimental S–N data, the predicted results by using GP distribution is relatively suitable. From the viewpoint of reliability, the modeling method of interior S–N curve with the maximum defect size at a given probability is satisfactory.

Application of the Maximum Undamaged Defect Size (d max) Concept in Fiber-Reinforced Concrete Pavements

Many fiber types are used in fiber-reinforced concrete (FRC) pavements. The maximum undamaged defect size (d max) concept has been applied to predict notch-based fracture in different types of concrete. The present paper applies this concept to different types of FRC pavement, namely, glass fiber-reinforced concrete pavement and steel fiber-reinforced concrete pavement. Due to the quasi-brittle manner of concrete, various fracture models have been developed to study the crack propagation in the pavement structures. The fracture energy was determined based on the recommendation of the RILEM Committee 50-FMC. An experimental study was carried out to investigate the effect of adding short fiber, steel or glass, in controlling the fracture energy of concrete. The analysis was invoked for constant fiber length of 25mm. The flexure test of single-edge notched and unnotched specimens was performed using three-point bending configuration. Four different values of crack-depth ratios were considered, mainly, 0.00, 0.10, 0.25, and 0.40. Experimental results showed that the calculated d max based on RILEM Committee 50-FMC is greater than the maximum aggregate size (MAZ). This means that there is no compatibility between the flexural strength of FRC and its fracture energy calculated based on RILEM Committee 50-FMC. Therefore, a modified calculation of the area of load-deflection curve was suggested to improve the reliability of fracture energy measured based on RILEM Committee 50-FMC. It is found based on this modification that d max is less than 0.7 MAZ.

Pedicled Buccal Fat Pad Flap as a Reliable Surgical Strategy for the Treatment of Medication-Related Osteonecrosis of the Jaw

The purpose of this study was to evaluate the coverage of the pedicled buccal fat pad flap (PBFP) and the long-term results of this treatment in patients with medication-related osteonecrosis of the jaw (MRONJ). Ten patients (2 men and 8 women; average age, 72.9 yr old) diagnosed with MRONJ were selected. Patients were treated with a PBFP. Data from patients regarding MRONJ stage, defect size, bone exposure after surgery, operation time, admission period, duration of antibiotic therapy, recurrence of disease, and postoperative complications were analyzed retrospectively. Six patients were diagnosed with MRONJ stage 2, and 4 patients were diagnosed with MRONJ stage 3. The maximum defect in the study was 62 × 18 mm. Among the 10 patients, there was only 1 bony exposure, which occurred on postoperative day 2 after receiving the PBFP. This exposure might have been due to an incomplete resection of the affected bone. There were no severe donor site morbidities, and all patients showed satisfactory healing without incident. According to this evaluation, the PBFP effectively covered a relatively large surgical defect. Complications were minimal, and there was no recurrence of bony exposure during follow-up. In conclusion, using the PBFP was a reliable treatment option for the management of denuded bone in patients with MRONJ.

Steel Fatigue Curves and its Impact on Bridge Performance

Fatigue of steel and other metal materials focused on fatigue strength and fatigue damage accumulation in two ways. Continuous hot air axially deformed bars fatigue tests showed that fatigue failure often occurs at the maximum defect reinforced, and bending fatigue tests of reinforced concrete structures, fatigue failure often occurs in areas of reinforced concrete curved split effective cross-sectional area decreases place. This paper studies the construction of reinforced fatigue effect on the structural performance and the fatigue reliability theory has some theoretical significance.

A hybrid framework based on SIPOC and Six Sigma DMAIC for improving process dimensions in supply chain network

Purpose– The purpose of this paper is to introduce a hybrid framework (suppliers, inputs, process, output and customers+define, measure, analyze, improve and control (SIPOC+DMAIC)) aimed at improving supply chain management (SCM) process dimensions in a supply chain (SC) network.Design/methodology/approach– Based upon the critical review of literature, process dimensions (average outgoing quality limit (AOQL), average outgoing quality (AOQ), processZ, defect per million opportunity) critical to SCM performance were identified. A framework consisting of three phases, i.e., design, implementation and results has been conceptualized and a case from paint industry is investigated. Implementation framework makes use of SIPOC model and Six Sigma DMAIC methodology. The goals of the study were achieved by using Six Sigma tools such as brainstorming sessions; root cause analysis, histograms, statistical tools such as control charts and process capability analysis.Findings– Authors made an attempt to propose a conceptual framework for improving process dimensions in a SC network. It is observed from the results that selection of appropriate strategies for improving process performance based upon experiences, and use of statistical tools by cross-functional teams with an effective coordination, guarantees success. Metrics such as AOQL shows the maximum worst possible defective or defect rate for the AOQ. ProcessZhelps to know about sigma capability of the process.Research limitations/implications– The framework so developed is tested in a single company manufacturing batches of paint. The study has important implications for the industry since it tries to integrate SCM process dimensions which would help in successful implementation of SCM practices in firm by following the DMAIC process. The framework enables the practitioners to investigate the process and demonstrate improvements using DMAIC which makes use of statistical tools.Originality/value– Although process dimensions related to SCM are critical to organization competitiveness, research so far has tended to focus on supply chain operations and reference model, balanced scorecard, total quality management, activity-based costing, just in time, etc., but in literature hardly any description of the SIPOC-DMAIC model to improve SCM process performance is provided. The use of statistics in DMAIC provides better insight into the process performance, and process control.

Massive Bone Defect Compromises Postoperative Cup Survivorship of Acetabular Revision Hip Arthroplasty with Impaction Bone Grafting

We evaluated 66 acetabular revision arthroplasties using cemented cup with impaction bone grafting (IBG) to detect the extent that bone defect affects the outcome. We defined the maximum acetabular defect distance (MADD), which indicates the greatest depth of the grafted layer. Cup survival analysis with aseptic loosening as the endpoint revealed that the “MADD≤20mm” group showed higher survivorship than the “MADD>20mm” group (95% vs. 74%, P=0.034), and that the simple-wall-defect group (none or one mesh used) showed higher survivorship than the complex-wall-defect group (two meshes used) (96% vs. 73%, P=0.044). A favorable indication for acetabular IBG reconstruction is cases in which those cups can be placed at≤20mm MADD with a simple wall defect.

Role of Surface Chemistry of Ceria Nanoparticles in CMP

Ceria has been widely used as an abrasive for polishing SiO2 film due to the high removal rate of SiO2 during Shallow Trench Isolation (STI) CMP.1 As the scale of transistor has been reduced, the number of maximum acceptable defects was decreased. Recently, numerous researchers have studied prevention of defect formation on the SiO2 film by using solution-grown ceria with spherical shape. Although solution-grown ceria is spherical shape and smaller particle size, it leads to unexpected results such as removal rate of SiO2 and higher defects compared to solid-state ceria with irregular shape. Recently, the study of surface chemistry appears to be more important than morphology, as ceria reacts with the SiO2film to remove it.Here, the effect of the surface chemistry of solution-grown ceria on the CMP performance was investigated. Nitrate- and hydroxyl-functionalized ceria nanoparticles were prepared by ion-exchange method.Figure 1(a) shows the adsorption behavior of silicate ions on nitrate- and hydroxyl-ceria particles at pH 7.0. The presence of surface nitrate group induces high affinity between ceria particles and silicate ions at pH 7. Figure 1 (b) shows the effect of nitrate group on the surface on the CMP performance. Nitrate-ceria particles increase the removal rate of SiO2film, which correlates well with the adsorption behavior of silicate ions on the ceria particles.To interpret the adsorption behavior of nitrate- and hydroxyl-functionalized ceria particles, the adsorption reaction at the molecular level through quantum mechanical calculation was investigated.2 As the second step, the hydroxyl-ceria adsorption on the H-terminated SiO2 surface is water generating reaction (Figure 2e). The binding energies of the both cases are -2.865 and -3.813 eV, respectively. On the other hand, only one step adsorption was considered for the nitrate-ceria without generating water molecule (Figure 2f). The binding energy of this nitrate ceria on the SiO2surface is much higher than that of the hydroxyl-ceria as -4.383 eV.In this study, we revealed that surface functional groups such as hydroxyl and nitrate groups have a significant influence on the characteristics of CMP. The adsorption behavior based on surface chemistry is important for understanding of reaction between ceria and SiO2. Acknowledgement This work was supported by the Global Research Laboratory (GRL) Program (K20704000003TA050000310) through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT (Information and Communication Technologies) and Future Planning, and the International Cooperation program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government of Ministry of Trade, Industry & Energy (2011T100100369) Reference [1] Cook, L. M.“Chemical Processes in Glass Polishing.” Journal of Non-Crystalline Solids, 120, (1-3), 152-171, (1990)[2] Perdew, J. P. et al. “Accurate and Simple Analytic Representation of the Electron-Gas Correlation-Energy” Physical Review B, 45, (23), 13244-13249, (1992)

A flexible modelling framework leading to a probabilistic multiaxial Kitagawa-Takahashi diagram: Applied to cast Al-Si alloys

The aim of this work is to propose simple analytical tools to predict the fatigue strength of cast aluminium components as a function of the casting process and post-cast treatment. The proposed methodology is based on the Murakami approach to predict the maximum defect size and a flexible modelling framework which leads to the construction of a probabilistic, multiaxial Kitagawa-Takahashi diagram. This framework is capable of modelling two independent co-existing fatigue damage mechanisms. This methodology will be applied to fatigue data taken from the literature as well as tests conducted on AlSi7 cast specimens manufactured via three different processes.

Estimation of local fatigue behaviour in A356–T6 gravity die cast engine head based on solidification defects content

Al–Si–Mg cast alloys have widespread applications, especially in the aerospace and automotive industries, due to their excellent combination of castability and high specific strength. Among Al–Si alloys, hypoeutectic A356 (Al–7Si–0·3Mg) ranks as one of the most widely used for the production of a variety of components, including engine blocks and engine heads, due to its excellent castability and good mechanical properties. The microstructure of this alloy greatly depends on chemical composition, solidification conditions, metal soundness and heat treatment. Furthermore, its mechanical properties are strongly affected by solidification microstructure and defects, which can vary greatly in complex shaped castings. Among the different microstructural features, only secondary dendrite arm spacing and percentage defect content can currently be predicted with sufficient accuracy by casting simulation software. This makes the prediction of the fatigue life of complex shaped Al–Si castings very difficult, since it is widely accepted that fatigue behaviour mainly depends on the size of solidification defects (gas pores and cavity shrinkages). In this study, the experimental work was carried out on an industrial A356–T6 gravity die cast engine head, with the aim of finding relationships among the main microstructural features and solidification defect parameters. The goal of this analysis was to correlate the defect size, which is the most important variable affecting the fatigue behaviour, to the other microstructural parameters that can be predicted by casting simulation software. Moreover, by applying literature models for fatigue behaviour prediction, based on maximum defect size, the local expected fatigue life/fatigue limit on a section of the casting will be evaluated and compared with those obtained by rotating bending fatigue tests. This study would demonstrate the effectiveness of a new approach of coengineering design, with a strong synergy between the structural finite element method and the casting simulation process, able to estimate the local fatigue strength in complex shaped A356 castings.

Effect of Test Zone Selection for Evaluating Bending Strength of Lumber

This study investigated the effect of test zone selection for evaluating bending strength of visually graded lumber. This will contribute to the understanding of two different methods under different standards. In method I, the major defect was randomly placed in the test specimen. In method II, the major defect was randomly placed in the maximum moment zone (MMZ). The results showed that the method II is more accurate for reflecting the effect of defects governing the grade of lumber. Unless the maximum strength-reducing defect (MSRD) is placed in MMZ, the evaluated value would be higher than that of MSRD. For evaluating the modulus of rupture (MOR) of visually graded lumber in test set-up of Method I, the Eq. (5) needs to be considered.

A comparison between size of the occluder device and two-dimensional transoesophageal echocardiographic sizing of the ostium secundum atrial septal defect : cardiovascular topics

Transcatheter closure of a secundum atrial septal defect (ASD II) has become an effective alternative for surgical treatment. In this study we evaluated the correlation between the two-dimensional transoesophageal echocardiographic (2D TEE) sizing of ASDs and the actual diameter of occluders in patients undergoing device closure. The records of 54 patients who underwent transcatheter ASD closure were reviewed. ASD characteristics and maximum defect diameter were evaluated using preprocedure 2D TEE images. Appropriate device size was determined by the balloon sizing method, which measures the balloon occlusive diameter (BOD) via TEE and fluoroscopy. ASD closure was performed under continuous TEE monitoring using the Amplatzer occluder in all patients. The mean of the TEE-derived maximum defect diameter was significantly lower than the mean of the BOD (17.8 ± 4.5 vs 22.1 ± 5.1 mm; p < 0.001) and the mean size of the implanted occluder device (17.8 ± 4.5 vs 23.3 ± 5.1 mm; p < 0.001). However, a good correlation was found between the TEE-derived defect size and the BOD (BOD = 0.898 × TEE defect size + 6.212, R = 0.824; p < 0.001) and between the TEE measurement and the final size of the implanted Amplatzer (device size = 0.928 × TEE defect size + 6.853, R = 0.822; p < 0.001). 2D TEE may provide a good equation to predict the BOD or the size of the occluder device; however, further studies are needed to investigate whether it is feasible to perform transcatheter ASD occlusion without balloon sizing.

A Runge-Kutta BVODE Solver with Global Error and Defect Control

Boundary value ordinary differential equations (BVODEs) are systems of ODEs with boundary conditions imposed at two or more distinct points. The global error (GE) of a numerical solution to a BVODE is the amount by which the numerical solution differs from the exact solution. The defect is the amount by which the numerical solution fails to satisfy the ODEs and boundary conditions. Although GE control is often familiar to users, the defect controlled numerical solution can be interpreted as the exact solution to a perturbation of the original BVODE. Software packages based on GE control and on defect control are in wide use. The defect control solver, BVP_SOLVER, can provide an a posteriori estimate of the GE using Richardson extrapolation. In this article, we consider three more strategies for GE estimation based on (i) the direct use of a higher-order discretization formula (HO), (ii) the use of a higher-order discretization formula within a deferred correction (DC) framework, and (iii) the product of an estimate of the maximum defect and an estimate of the BVODE conditioning constant, and demonstrate that the HO and DC approaches have superior performance. We also modify BVP_SOLVER to introduce GE control .

The effect of four sprue shapes on the quality of cobalt-chromium cast removable partial denture frame-works.

Statement of Problem:Sprue design is a factor that controls the velocity and adequate supply of metal to the mould. Currently various manufacturers recommend different shapes of sprue, which have not been advocated in textbooks and literature is lacking for their routine applications.Purpose:This in vitro study was carried out to determine the efficacy of four sprue shapes in producing complete, void free cobalt-chrome removable partial denture frameworks.Materials and Methods:A brass metal die with a Kennedy class III, modification 1, partially edentulous arch was used and four sprue shapes (Group A-Ribbon, Group B-Square, Group C-Round and Group D- Round with reservoir) were evaluated. 40 refractory casts were made, 10 wax patterns for each sprue design were waxed up, invested with phosphate bonded investment material and castings done with induction casting machine by the same operator under standardized protocols. The cast frameworks were evaluated for 1. The defects observed visually before finishing and polishing procedures, 2. Fit on the master die as seen with naked eye and 3. Defects on radiographic evaluation. Data were tabulated and statistically analyzed with 1-way ANOVA followed by Student ‘t’ test.Results:The results differed significantly (P < 0.0001) between the Groups with maximum defects in the castings of Group A followed in decreasing order by Group B, Group C and Group D. When comparing between the Groups (P < 0.05), the defects in Groups C and D was significantly lower than Group A and Group B.Conclusions:Round sprues with reservoir produced most satisfactory fit of castings with minimum number of internal and external defects.

A New Model for Light-induced Degradation by B-O Defects in p- and n-type Silicon

Light-induced degradation of the carrier lifetime in silicon due to the formation of boron-oxygen defects has been investigated using photoluminescence measurements. A finite difference simulation method has also been created to test theoretical models of the factors controlling defect generation. Experimental photoluminescence data is compared with simulated results. It is found that the maximum defect density in both p- and n-type material can be described as a function of the hole density during degradation.

NDE Inspections and Simulation of Defects in Composite-Sintered Bushes

Bush is one of machine and automobile parts like brake used in drums and hubs in particular. Such bush parts are used for bearings of heavy-duty, large cars requiring wear resistance and high load carrying capacity. High temperature diffusion bonding has been applied for holding the both materials of the bushing together, which are outer steel materials and inner composite-sintered bushings. Therefore, it is very important evaluate the bonding integrity in manufacturing process. A simulation has been performed in order to evaluate the maximum defect sizes. Also, ultrasonic C-scan tests were performed for finding the defect in the composite-sintered bushings with the size of inherent flaws.

Comparison of Outcomes of Open and Minimally-Invasive Component Separation Techniques

INTRODUCTION: There have been several investigations comparing the outcomes of open and minimally invasive component separation techniques. It has been suggested that minimally invasive component separation techniques reduce wound complications over open techniques presumably through the preservation of abdominal wall perforators supplying the skin and subcutaneous tissue. METHODS: A retrospective review of patients undergoing either open or minimally invasive component separation technique was performed. Patient-related variables were compared including age, BMI, maximum defect width, and previous ventral hernia repairs. Outcome variables were evaluated and included hernia recurrence and wound complications. RESULTS: Twenty consecutive patients in each arm were identified. Average age was 45.6 in the patients undergoing OCS repair, and 44.5 in the patients undergoing MICS repair. Average BMI was 31.4 kg/m2 in patients undergoing OCS repair and 29.3 kg/m2 in patients undergoing MICS repair. Average transverse defect width was 12.1 cm for the open CS group and 10.7 cm in the MICS group. The OCS group had an average of 1.9 previous ventral hernia repairs, whereas the MICS group had an average of 1.7 prior repairs. Recurrence rate was 5% for the OCS group, and 0% in the MICS group. Wound complications were observed in 45% of the OCS technique patients and in 10% of the MICS technique patients. Mean follow-up of all patients was 16 months.Table 1: Table 1.CONCLUSION: The subset of patients in which an OCS was performed demonstrated similar patient demographics as patients in which MICS repair was performed. The rate of recurrence was similar at short-term follow-up; however the rate of wound complications was significantly higher in the OCS repair group.

Defect generation by argon implantation: microscopy characterization and electrical properties

AbstractIn this work defects generated by argon implantation were studied both by Transmission Electron Microscopy (TEM) inspections and by measurements of the defect electrical activity at the oxide‐silicon interface and in the bulk. TEM analyses showed defects close to the surface for argon doses equal or larger than 1013cm‐2, and stacking faults in the sample implanted with 1015 cm‐2 dose. The maximum defect depth was about 50 nm. The generation lifetime was heavily degraded even with the lowest argon dose. Besides, positive charge and a relevant population of interface states were found to be related to argon implantation. In addition, DLTS revealed four deep levels starting with the samples implanted with 1013cm‐2 argon dose. These levels evolve with increasing the argon dose and are located much deeper than the defects revealed by TEM, i.e. down to a few micron depth. The dependence of the signal amplitude on the filling pulse width was analyzed, and showed that all the observed levels are related to extended defects. Kinetic Monte Carlo simulations of the implantation and annealing process indicate that argon atoms interact with implantation‐induced defects and enhance the formation of extended defects. (© 2012 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Ion irradiation of electronic-type-separated single wall carbon nanotubes: A model for radiation effects in nanostructured carbon

The structural and electrical properties of electronic-type-separated (metallic and semiconducting) single wall carbon nanotube (SWCNT) thin-films have been investigated after irradiation with 150 keV 11B+ and 150 keV 31P+ with fluences ranging from 1012 to 1015 ions/cm2. Raman spectroscopy results indicate that the ratio of the Raman D to G′ band peak intensities (D/G′) is a more sensitive indicator of SWCNT structural modification induced by ion irradiation by one order of magnitude compared to the ratio of the Raman D to G band peak intensities (D/G). The increase in sheet resistance (Rs) of the thin-films follows a similar trend as the D/G′ ratio, suggesting that the radiation induced variation in bulk electrical transport for both electronic-types is equal and related to localized defect generation. The characterization results for the various samples are compared based on the displacement damage dose (DDD) imparted to the sample, which is material and damage source independent. Therefore, it is possible to extend the analysis to include data from irradiation of transferred CVD-graphene films on SiO2/Si substrates using 35 keV C+ ions, and compare the observed changes at equivalent levels of ion irradiation-induced damage to that observed in the SWCNT thin-film samples. Ultimately, a model is developed for the prediction of the radiation response of nanostructured carbon materials based on the DDD for any incident ion with low-energy recoil spectra. The model is also related to the defect concentration, and subsequently the effective defect-to-defect length, and yields a maximum defect concentration (minimum defect-to-defect length) above which the bulk electrical transport properties in SWCNT thin-films and large graphene-based electronic devices rapidly degrade when exposed to harsh environments.

Clinical outcomes of myelomeningocele defect closure over 10 years

We report our surgical procedures for the closure of myelomeningocele defects. A retrospective analysis of 162 patients (74 male [45.7%], 88 female [54.3%]) with myelomeningocele was performed and the relationship between hydrocephalus, neurological status and the level and size of the myelomeningocele was described according to type of defect closure. Patients were divided into four groups according to the size of the defect, which was classified into ranges of 0–24cm2, 25–39cm2, 40–60cm2 and >60cm2. Myelomeningocele occurred in the lumbar region in 114 patients (70%). The minimum defect size was 3×2cm, and the maximum defect size was 15×15cm (mean defect size=34.64cm2). We found that primary closure can be performed on clean, small defects with an intact sac that contains cerebrospinal fluid and the neural placode. For defects larger than 25cm2 that contained perforated sacculas, more soft tissue for well-vascularized coverage was required. Bilateral V–Y fasciocutaneous flaps are a good choice for immediate coverage of myelomeningocele defects.