Average Defect Diameter Research Articles

Nondestructive Inspection and Quantification of Select Interface Defects in Honeycomb Sandwich Panels.

Honeycomb sandwich panels are utilized in many industrial applications due to their high bending resistance relative to their weight. Defects between the core and the facesheet compromise their integrity and efficiency due to the inability to transfer loads. The material system studied in the present paper is a unidirectional carbon fiber composite facesheet with a honeycomb core with a variety of defects at the interface between the two material systems. Current nondestructive techniques focus on defect detectability, whereas the presented method uses high-frequency ultrasound testing (UT) to detect and quantify the defect geometry and defect type. Testing is performed using two approaches, a laboratory scale immersion tank and a novel portable UT system, both of which utilize only single-side access to the part. Coupons are presented with defects spanning from 5 to 40 mm in diameter, whereas defects in the range of 15-25 mm and smaller are considered below the detectability limits of existing inspection methods. Defect types studied include missing adhesive, unintentional foreign objects that occur during the manufacturing process, damaged core, and removed core sections. An algorithm is presented to quantify the defect perimeter. The provided results demonstrate successful defect detection, with an average defect diameter error of 0.6 mm across all coupons studied in the immersion system and 1.1 mm for the portable system. The best accuracy comes from the missing adhesive coupons, with an average error of 0.3 mm. Conversely, the worst results come from the missing or damaged honeycomb coupons, with an error average of 0.7 mm, well below the standard detectability levels of 15-25 mm.

Predicting outcomes following second intent healing of periocular surgical defects.

Traditionally, second intent healing (SIH) in the periocular region is reserved for small and/or concave defects, particularly those located on the medial canthus. The purpose of this study was to identify factors impacting outcomes of SIH for periocular tumors following Mohs micrographic surgery (MMS). Retrospective analysis was performed of all periocular lesions treated with MMS followed by SIH from a single academic surgical center over a 5-year period. Data regarding tumor characteristics and follow-up was recorded. The modified Manchester scale was utilized to evaluate scar outcomes. Of the 39 tumors included, 14 (35.9%) were located on the lower eyelid, 12 (30.8%) on the upper eyelid, 6 (15.4%) on the lateral canthus, and 7 (17.9%) on the medial canthus. Involvement of the eyelid margin was seen in 11 (28.2%) of cases. The average defect diameter and area were 1.3cm and 1.04cm-squared. Twenty-three cases (59.0%) healed with optimal results. Larger defects were significantly associated with poorer outcomes of SIH (odds ratio 0.205, p = 0.017 by multivariate analysis). Anatomic location, involvement of the lid margin, age, and follow-up interval were not significant factors; however, medial canthus defects were least likely to heal with optimal results. On average, medial canthal lesions were larger in size (mean diameter 1.76cm, mean area 1.97cm-squared). This retrospective study suggests that periorbital defects in all locations with area less than 1.04 cm2 heal well by SIH. In this cohort, larger lesions on the medial canthus healed with worse outcomes.

Reconstruction of Small and Medium-Sized Nasal Defects Using an Omega Advancement Flap.

The nose is the most common area where malignant skin tumors occur. Repair with a flap after tumor excision provides esthetically and functionally acceptable results. In this study, we aimed to present the use of an omega (Ω) advancement flap, which can be applied in all anatomic regions of the nose, in 2 cm or smaller defects. Between 2015 and 2017, 18 patients underwent repair with omega (Ω) advancement flap in the nose after tumor removal. The pathology of 17 patients was basal cell carcinoma, and keratoacanthoma in 1 patient. The average defect diameter was 1.6 × 1.56 cm. The defects were in the nasal tip, nasal wing, lateral nasal wall, and supratip region. After tumors were excised from the safe margin, and were repaired using an omega advancement flap in the same session. No flap necrosis, dehiscence, or infection was observed in the early postoperative period. Three patients developed hematoma under the flap, which was drained. No tumor recurrence was observed during the postoperative follow-up period. The results were satisfactory in all patients. The omega advancement flap is a safe procedure that can be easily applied in the same session for the repair of small-to-medium-sized nasal defects.

Variations in Frontonasal Flap Design for Single-Stage Reconstruction of the Nasal Tip.

Single-stage reconstruction of the nasal tip using frontonasal flaps yields variable results. Variations in flap design were used to optimize outcome. Consecutive nasal tip reconstructions using frontonasal flaps performed by the author during a 6-year period were studied retrospectively. Patients were followed up clinically and charts were reviewed for defect size, vertical orientation (tip versus supratip), and horizontal orientation (central versus lateral). Surgical reports and digital photographs were evaluated for flap design that was adapted to the defect, individual anatomy, and the nasal subunit concept. Flaps were classified by size (standard versus extended), proximal scar configuration (angular versus curved), and distal scar configuration (straight versus stairstep). Surgical complications and aesthetic outcomes were evaluated. Twenty-nine frontonasal flaps were performed in 16 female and 13 male patients with a mean age of 73 years. The average defect diameter was 2 cm. The average surface area was 4 cm. Primary defects were located at the tip in 22 cases and the supratip in seven cases, with 19 being lateral and 10 being central. Standard flaps were chosen in 13 patients and extended flaps in 16 patients. Proximal scar configuration was angular in 20 cases and curved in nine cases. Distals scar configuration was straight in 21 patients and stairstep in eight cases. Minor flap complications occurred in eight patients. Outcome was rated good to excellent in 97 percent of patients. Aesthetically pleasing single-stage reconstruction of the nasal tip is attainable using an anatomically based approach to frontonasal flap design. Therapeutic, IV.

The changes of macular microstructure in large idiopathic macular hole after vitrectomy combined with internal limiting membrane transplantation or internal limiting membrane peeling

Objective To observe the different changes of macular microstructure in patients with large idiopathic macular hole (IMH) treated with vitrectomy combined with internal limiting membrane (ILM) transplantation or not. Methods Forty eyes in 40 consecutive patients with giant IMH (≥500 μm) were included in the study. Twenty eyes received vitrectomy with ILM transplantation (ILM transplantation group) and others with ILM peel off (ILM removal group). During the operation, a proper size of the ILM was removed and filled in the bottom of the macular hole. The age, duration of disease and the ocular laterality of the two groups of patients were not statistically significant (P>0.05). Minimum resolution angle in logarithmic (logMAR) best corrected visual acuity (BCVA) and frequency domain optical coherence tomography (SD-OCT) scan were examined. There was no statistically significant difference in logMAR BCVA, average defect diameter of photoreceptor ellipsoid (IS/OS) and average defect diameter of external limiting membrane (ELM) between two groups (t=0.128, 1.452, 1.321; P>0.05). The logMAR BCVA and SD-OCT were examined on 1, 3, 6, 12 months postoperatively. Results On 1 month after the surgery, there was no statistically significant difference in logMAR BCVA, average defect diameter of IS/OS and average defect diameter of ELM between two groups (t=1.226, 1.435, 1.018; P>0.05). On 3, 6, 12 months after the surgery, compared with ILM removal group, the logMAR BCVA (t=2.059, 2.871, 2.415) increased and the average defect diameter of IS/OS (t=2.070, 2.110, 2.121) and ELM (t=2.034, 3.647, 3.556) significantly reduced in ILM transplantation group (P 0.05). Conclusion Compared with vitrectomy combined with ILM peeling surgery, the diameter of IS/OS and ELM defect were significantly decreased after vitrectomy combined with ILM transplantation in the patients with large IMH. Key words: Retinal perforations/surgery; Vitreoretinal surgery; Macula lutea/physiopathology

The use of porcine acellular dermal matrix in a bridge technique for complex abdominal wall reconstruction: an outcome analysis

BackgroundOutcomes using the porcine acellular dermal matrix (PADM) in abdominal wall reconstruction (AWR) have been reported when used for midline reinforcement; however, there have been no reports focused on outcomes when used as a bridging mesh. MethodsA retrospective review was conducted of all patients who underwent AWR with a non–cross-linked PADM as a bridged repair without midline fascial approximation. ResultsNine patients were identified with an average follow-up of 546 days. The average preoperative hernia defect diameter was 22.4 cm. After PADM placement, the average defect diameter was 9.8 cm. Complications occurred in 55.6% of patients, with PADM exposure occurring in all of these patients. No PADM was explanted, and all patients eventually healed. Abdominal wall eventration and/or recurrence occurred in 8 of 9 (88.9%) patients. ConclusionsWhen fascial approximation cannot be achieved, PADM bridging may be the best option to avoid complications associated with synthetic mesh. However, there is a high potential for abdominal wall eventration and/or recurrence.

Clinical follow-up research after transcatheter closure of adult giant ASD

ObjectiveTo evaluate clinical effects of transcatheter closure of giant ASD in adults.MethodsWe selected 87 patients from June 2003 to November 2009 who underwent successfully transcatheter closure of adult giant Atrial...

Effectiveness of Composite Bone Graft Substitute Plugs in the Treatment of Chondral and Osteochondral Lesions of the Talus

A review of outcomes in 13 patients with talar dome osteochondral or chondral lesions treated with a bone graft substitute plug was undertaken in an effort to evaluate its effectiveness in comparison with other reported surgical techniques. Mean patient age was 36.4 (range 16 to 57) years. Mean follow-up was 30.1 (range 7 to 43) months. Medial malleolar osteotomy was performed in 9 (69.23%) cases. Average defect diameter was 9.8 (range 5 to 20) mm. Pain decreased significantly from 6.2 (range 3 to 9) to 4.0 (range 0 to 9) ( P = .009). Postoperative American Orthopaedic Foot and Ankle Society Ankle-Hindfoot scores averaged 67.3 (range 26 to 100). Younger age, smaller defect size, and avoidance of medial malleolar osteotomy resulted in better outcomes. Mean Short Form-36 scores for the study group fell below US norms in all categories, and 12 (92.31%) ankles demonstrated persistent lesions radiographically. Postoperative magnetic resonance imaging in 2 (15.39%) patients demonstrated enlarged lesions, and 4 (30.77%) patients underwent revision surgery that revealed abnormal cartilage around the implant site. Complications included 1 (7.69%) deep venous thrombosis, 1 (7.69%) arthrofibrosis, and 1 (7.69%) superficial neuritis. Despite some improvement in pain, comparison of functional outcome showed bone graft substitute plug implantation to be less effective overall than other operative interventions. Future investigations with more specific selection criteria are warranted to gain further insight into the efficacy of these bone graft substitute plugs.

Microstructure of V-4Cr-4Ti Following Low Temperature Neutron Irradiation

AbstractThe V-4Cr-4Ti alloy displays excellent mechanical properties, including a ductile-to-brittle transition temperature (DBTT) below -200°C in the unirradiated condition. Specimens of this alloy were fission neutron-irradiated in the High Flux Beam Reactor (HFBR) at Brookhaven National Laboratory (BNL) to a dose of 0.4 dpa at temperatures from 100 to 275°C. Mechanical testing showed significant irradiation hardening in the alloy which increased with increasing irradiation temperature. Charpy impact testing also showed a dramatic increase in the DBTT on the order of 200 to 350°c. The mechanical property changes are correlated with preliminary results from the transmission electron microscopy (TEM) analysis of the defect microstructure resulting from the low-dose neutron irradiations. The TEM analysis of the irradiated material showed a nearly constant defect density of ∼1.6 × 1023 m−3, with an average defect diameter of slightly greater than 3 nm.

The observation of damage regions produced by neutron irradiation in lithium-doped silicon solar cells

Regions of lattice disorder produced in lithium-doped float-zone melted n/p-type silicon solar cells by irradiation with mono-energetic neutrons at doses between 1010 and 1013/cm2 have been studied. The defect regions were revealed by chemically etching the surface of the solar cells and by observing carbon replicas in an electron microscope. It was found that the defect density increased with increasing irradiation dose and increased lithium content, whereas the average defect diameter was found to decrease. From thermal annealing experiments it was found that in the lithium-doped material the defect structure was stable at temperatures between 300 and 1200° K. This was found to be in contrast to the undoped material where at the lowest doses considerable annealing was observed to occur. The above results are discussed in terms of the theoretical predictions and models of defect clusters proposed by Gossick and Crawford and Cleland.