Small Size Defects Research Articles

Very High Cycle Fatigue Behavior of 25Cr2Ni2MoV Steel Welded Joint

Conventional fatigue test is conducted in 25Cr2Ni2MoV steel welded joint specimen at room temperature. The fatigue failure mechanism in welded joint is investigated by fatigue test and microscopic analyses. Results show that the stress-fatigue life relationship presented a stepwise shape. In high cycle fatigue(HCF) regime, base metal is preferential fracture sites, which are originated at surface or subsurface inclusions. Whereas in the very high cycle fatigue(VHCF) regime, fatigue cracks are always initiated at pores in the weld metal. The fatigue life will be longer in the condition of small surface defect size or interior defect as fatigue crack initiation. Small surface defect with large interior defect has similar potential for crack initiation. Stress distribution of fatigue specimen at micro-defects are performed by finite element analyses, and it shows that the stress concentration around pore and inclusion in the weld metal are larger than inclusion in base metal. It is found that large quantities of granular particles disperse inclusions in base metal will form bigger defects and these defects are easier to initial fatigue crack than inclusions in the weld metal.

Evaluation of a treatment algorithm for acute traumatic osseous Bankart lesions resulting from first time dislocation of the shoulder with a two year follow-up

BackgroundStudies dealing with acute osseous Bankart lesions and corresponding treatment strategies are rare. The purpose of this study is to analyze the results after applying our treatment algorithm for acute glenoid rim fractures caused by first time traumatic anterior shoulder dislocations.Methods25 patients were included in this retrospective case series. All patients sustained a first time shoulder dislocation caused by ski or snowboard accidents. An osseous Bankart lesion was detected in all shoulders. Operative therapy was performed in patients with osseous defects of 5% or more, otherwise conservative therapy was initiated. Primary study outcome parameter was the Rowe score. Additionally, the outer rotation deficit and operative complications were analysed.Results12 patients showed a defect size of less than 5% and were treated conservatively. The average lesion size was 2%. For these patients, the Rowe score was excellent in 58%, good in 25%, and moderate in 17% of patients. Three patients (25%) complained about a feeling of instability. 13 patients had a lesion size of more than 5%, average 15%, and were treated operatively. The Rowe score for this group was excellent in 54%, good in 31%, and moderate results in 15% of patients. One patient (8%) complained about a feeling of instability, without recurrent dislocations. There were no statistically significant differences between both study groups (ROWE score: p = 0.98).ConclusionsApplying our treatment algorithm for acute osseous Bankart lesions consisting of a conservative strategy for small defect sizes and a surgical approach for medium-sized and large defects leads to encouraging mid-term results and a low rate of recurrent instability in active patients.

English

AIMS: Distal leg defects are very difficult to cover because its structure its vicarious blood supply paucity of the muscles. Peroneus brevis muscle type 2 muscle long & slender to cover small & medium size defects. Prospective study conducted in Victoria hospital to cover the post traumatic distal leg defects. 20cases of distal leg defects exposing vital structure which require the flap cover. 16 patients are male, patients ranging from 18yrs to 65yrs. RESULTS AND CONCLUSIONS: 18 flaps survived. 2cases flap loss 2 cases graft loss. No functional deficit noted, less donor defect. Ideal flap for the small & medium size defects of distal leg.

Tension pneumocephalus: an extremely small defect leading to an extremely serious problem

BackgroundPneumocephalus is a pathology characterized by air influx into the intracranial region. It may occur after head trauma and rarely after endoscopic sinus surgery. As the amount of air increases, this can cause neurological disorders with a mass effect and this condition is called tension pneumocephalus. Case descriptionOur case is a 65-year-old woman. Tension pneumocephalus developed 12h after endoscopic sinus surgery performed for nasal polypectomy. Since tension pneumocephalus developed very rapidly in the patient creating a herniation table, the patient was taken to theater immediately. A burr-hole was drilled into the skull and a small defect in the ethmoid roof was closed with a layered closure technique. Post-operative conservative treatment was applied (bed rest, raising the bed head, meningitis prophylaxis, loop diuretics, abstaining from maneuvers increasing the Valsalva). DiscussionIn the literature, it is stated that, in the case of a small defect, spontaneous resolution may be provided with conservative treatment, but as the size of the defect increases, neurological effects will occur more quickly and be more obvious. In our case, a herniation table developed leading to neurological and vital problems in a more rapid and more obvious way than in other tension pneumocephalus cases developing after endoscopic sinus surgery. We consider that this situation is related to a very small defect size. ConclusionTension pneumocephalus is a complication rarely seen after endoscopic sinus surgery, but if it is not treated immediately, it may give rise to serious morbidity and mortality concerns. The clinical course developing after tension pneumocephalus may be very serious when very small defects are involved.

Management of Cranial Bone Defects

Reconstruction of cranial bone defects is one of the most challenging problems in reconstructive surgery. The timing of reconstruction, the location of the defect, the materials to be used, and the medical history of the patient are parameters that have been mostly discussed in the literature. To the best of our knowledge, there has not been any published classification for the cranial bone defect reconstruction according to defect size. Twelve patients underwent reconstruction of cranial vault defects. Cranial bone defects were classified into 3 groups according to the size of the defect. The small-sized group included the defects smaller than 25 cm(2), the medium-sized group included the defects between 25 to 200 cm(2), and the large-sized group included the defects larger than 200 cm(2). The small-sized defects were reconstructed with split calvarial graft, demineralized bone matrix, or hydroxyapatite cement; the medium-sized defects were reconstructed with split calvarial graft or allogenic bone graft; and the large-sized defects were reconstructed with methyl methacrylate, autoclaved bone, or porous polyethylene. Two patients needed revision for irregularities with demineralized bone matrix. Other patients had no skull defects or irregularities for which revision was suggested. We believe that the size of the defect is important for the reconstruction of cranial vault defects and that using a standard algorithm can increase the success rate.

Reconstruction of Singular Eyelid Defects in Aging Individuals Based on Facial Aesthetic Subunits

In consideration of the distinctive structural characteristics of the eyelid, the optimally matching donor site to the original recipient site skin should be selected when a full-thickness skin graft is anticipated in a small-sized or medium-sized eyelid defect in middle-aged or elderly patients. Eight patients ranging in age from 47 to 71 years suffered singular eyelid defects of different causes. Based on the location, shape, and degree of the defects, we removed the redundant skin as a skin graft from the same side in the contralateral eyelid in a routine blepharoplasty procedure and transferred the graft to repair the defect. The skin grafts survived in all cases, and the incisions healed primarily. The eyelid laxity improved, and no complications occurred. All cases were followed up for 3 months to 2 years, the quality of skin grafts was similar to that of the surrounding skin, and the activity was ideal. When an eyelid defect is not amenable to direct closure and skin grafting is selected, the proper donor site is vital to the final outcome. The same facial aesthetic subunits, such as sufficient laxity in the contralateral eyelid skin in middle-aged and elderly patients, can provide the best match with the recipient skin and represent the best donor site for defect reconstruction.

The effect of human hair keratin hydrogel on early cellular response to sciatic nerve injury in a rat model

Peripheral nerve injuries requiring surgery can be repaired by autograft, the clinical “gold standard”, allograft, or nerve conduits. Most published clinical studies show the effectiveness of nerve conduits in small size defects in sensory nerves. Many preclinical studies suggest that peripheral nerve regeneration through conduits can be enhanced and repair lengths increased with the use of a biomaterial filler in the conduit lumen. We have previously shown that a luminal hydrogel filler derived from human hair keratin (HHK) can improve electrophysiological and histological outcomes in mouse, rabbit, and non-human primate nerve injury models, but insight into potential mechanisms has been lacking. Based on the premise that a keratin biomaterial (KOS) hydrogel provides an instantaneous structural matrix within the lumen, the current study compares the cellular behavior elicited by KOS hydrogel to Matrigel (MAT) and saline (SAL) conduit fillers in a 1 cm rat sciatic nerve injury model at early stages of regeneration. While there was little difference in initial cellular influx, the KOS group showed earlier migration of dedifferentiated Schwann cells (SC) from the proximal nerve end compared to the other groups. The KOS group also showed faster SC dedifferentiation and myelin debris clearance, and decreased macrophage infiltration during Wallerian degeneration of the distal nerve tissue.

Strength of single lap joints with artificial defects

Adhesive joints encounter in-service defects that may have an impact on the joint strength. The objective of the present study was to understand in which situations defects can affect the joint strength. Two different types of adhesive were studied with different degrees of ductility as the stress distribution along the overlap depends on the adhesive's capacity to deform plastically. Three different steel adherends were used, from low strength and high ductility to very high strength, since the adherend yield strength is known to influence the joint mechanics. Rectangular and circular defects located in the middle of the overlap and of increasing size were studied. When a toughened structural adhesive is used with a high strength steel, there is an almost linear decrease in joint strength as the defect area increases. In the case of the brittle adhesive, the reduction in strength, as the defect size increases, is not proportional for small defect sizes, indicating that the end of the joint becomes more important due to local strains exceeding limiting values. When medium carbon or mild steel adherends are used, a non-linear decrease in strength is observed. For small defect sizes, there is no significant effect. But, as the size of the defect gets bigger, then a more rapid decrease in the strength of the joints is apparent. Failure is dominated by end effects for the case of mild and medium carbon steels (when the defect size is small).

Synthesis and photocatalytic behavior of BiVO4 with decahedral structure

Abstract Decahedral BiVO 4 was successfully synthesized with Tween-80 as a template by the microwave hydrothermal method. The effects of hydrothermal temperature and Tween-80 on crystal phase and morphology of the obtained BiVO 4 were investigated. The crystal phase and morphology were characterized by X-ray diffraction, field emission scanning electron microscopy and UV–vis diffuse reflectance spectroscopy. The results indicated that the as-prepared decahedral BiVO 4 was monoclinic. The photocatalytic behavior for methylene blue (MB) degradation was enhanced with the assistance of an appropriate amount of hydrogen peroxide (H 2 O 2 ) under visible light irradiation. The photocatalytic tests indicated that the photocatalytic efficiency of decahedral BiVO 4 synthesized at 180 °C was 63.5%. However, BiVO 4 sample synthesized at 160 °C showed the highest photocatalytic degradation rate, up to 81.6%, due to its small size and crystal defects.

Higher torsional mode suppression in a pipe for enhancing the first torsional mode by using magnetostrictive patch transducers

Small-sized defects in pipes can be better detected if the first nondispersive torsional mode is used in a higher frequency range. However, dispersive higher torsional modes accompany the first mode if the actuation frequency is above the first cutoff frequency, thereby making the detection difficult. This study proposes a new technique that is particularly useful for guided torsional waves in a pipe; it enhances the desired first nondispersive mode and suppresses the undesired second mode. The technique uses two transmitting transducers separated by an optimized distance and actuated with an optimized delay time. Unlike previous methods, such as a method tuning the delay time for desired mode enhancement and tuning the distance for undesired mode suppression, the proposed approach determines both the distance and delay time mainly to suppress the undesired second mode. With the selected values, the desired first mode is substantially enhanced. This phenomenon is unique in torsional waves, not longitudinal waves, for which delay time and distance controlling methods have been developed. After wave simulations were carried out to show why the proposed method is more effective for the case of torsional waves, several experiments using magnetostrictive transducers were performed to demonstrate the effectiveness of the proposed method.

Mozaicplasty Technique for Treatment of Reverse Hill-Sachs Lesion

Posterior shoulder dislocations can cause impaction of the anteromedial part of the humeral head: this is called a reverse Hill-Sachs lesion. Such defects may predispose to chronic instability of the shoulder and may require surgical intervention. However, to the best of our knowledge, these lesions have not been filled with the mozaicplasty technique using the patient’s own cartilage. A 24-year-old male patient was admitted to our hospital as a result of a seizure. Examination of the right shoulder revealed pain and restriction of motion in external rotation. Anteroposterior radiographs and computed tomography scans showed a locked posterior shoulder dislocation and fracture of the lesser tuberosity. Measurements presented a lesion including approximately 30% of the articular surface. Anteromedial cartilage defect was filled with autogenous osteochondral plugs harvested from both the knees. At the 2-year follow-up, the patient had no recurrent instability and supple range of motion of his shoulder. Treatment of reverse Hill-Sachs lesion varies depending on the percentage of articular surface involvement. In general, defects up to 40% of articular surface were treated with elevation of the cartilage, subscapularis shift, lesser tuberosity advancement, and filling defects with allografts. The described technique can be performed in young patients with unilateral small-sized or medium-sized defects while the anatomic reconstruction was performed. Computed tomography of the patient showed graft osseointegration to host bone and continuity of smooth articular surface.

Lower Lip Reconstruction Using Unilateral Nasolabial Gate Flap (Fujimori Technique)

Abstract Background: In the medical literature there are multiple reconstructive procedures for small and medium size defects of the lower lip, but only a few methods for larger defects involving the whole lower lip. Choosing the repairing procedure for larger lower lip defects must take into account two aspects: flap or flaps used should be local flaps, and suture lines should correspond to the natural facial creases or follow the functional lines of different facial aesthetic units. Finally, the flap or flaps should be large enough to restore the entire postexcisional defect. However, the more tissue is lost from the lower lip, the more challenging the reconstruction is from a functional and cosmetic point of view. Material and methods: During the last 2 years in the Oral and Maxillofacial Surgery Department of the County Emergency Clinical Hospital in Tîrgu Mureș, the unilateral Fujimori technique has been successfully used for the reconstruction of large lower lip defects in 4 patients with extended, neglected squamous cell carcinomas involving almost the whole lower lip tissue. These patients underwent complex surgical and oncological treatment. Surgery was performed in two stages: first, excision of the tumor and immediate lip reconstruction, and then removal of submandibular lymph nodes (level I), in the second stage. Results: The aesthetic and functional recovery of these patients was very good, with no need of other subsequent surgical corrections. Conclusions: The postoperative reconstruction of large defects of the lower lip is far from optimal, but it is very important to restore an adequate muscle function, the lip continence and a satisfactory facial appearance.

Application of dolabriform flap in repairing periorbital skin and soft tissue defects

Objective To discuss the efficacy and advantage of dolabriform flap in repairing periorbital skin and soft tissue defects.Methods 21 patients with periorbital skin disease were treated by radical resection,and then the adjacent or distant dolabriform flaps were designed for the one stage repair of skin and soft tissue defects in these cases according to the defect location,size,shape and neighborous skin conditions.The largest defect size was 3.5 cm × 4.5 cm,The smallest defect size was 1.2 cm × 1.5 cm.The largest ratio of hatchet pedicle width to axe handle length reached 1 ∶ 5,and the largest ratio of hatchet pedicle width to hatchet edge length was 1 ∶ 4.Results All of these dolabriform flaps in 21 patients survived well with primary incision healing.18 cases had been followed up for 3 to 12 months,showing that there was no deformation found on eyelids,eyebrow and nose,the colour of these flaps were similiar to that of the normal skin,without being fat and clumsy,all scars were almost invisible,and the cosmetic results were satisfactory.Conclusions Larger diameter of skin and soft tissue defect in different periorbital parts could be repaired individually with dolabriform flap according to the characters of natural lines,and it is a simple and flexible method for repairing periorbital skin defects,and can achieve satisfactory functional and cosmetic results. Key words: Face; Skin defect; Dolabriform flap; Tumor

Influence of Ammonia Gas Ambient in IPA Drying Process of the Single Wafer Cleaning System

High-performance drying techniques using IPA (isopropyl alcohol) are widely used in the silicon wafer cleaning process. IPA-based drying techniques help prevent the formation of watermarks because they effectively displace any water remaining on a wafer surface. They are thus frequently used in the single wafer cleaning system for advanced devices in which ultra-clean process performance is required. However, as devices are becoming physically smaller, the formation of extremely small defects during cleaning has become a serious problem. It is therefore important to elucidate the mechanism of the defect formation and to take measures to prevent it for future device technologies in which small-size defects can be killer defects during production. In this paper, we performed experiments focused on the process chamber atmosphere in IPA drying of the single wafer cleaning system and describe the mechanism of the defect formation.

Immersion effect of fluoride liquid into cavities of negative mold in thermal imprint

Around each concave imprinted pattern, the compressed air that is caused by the imprint pressure, generates capillary bridges; and in case of a convex imprinted pattern the trapped air remaining inside the concave mold pattern gives rise to bubble defects. Thus, in order to remove such defective moldings, we proposed an immersion nanoimprint method where a compressible gaseous material is replaced by perfluorotributylamine (Fluorinert FC-43) as an incompressible liquid material. However, the insertion steps result in an excessive amount of FC-43 left behind after its utilization, and continues to remain in the cavity of the negative mold. This problem was resolved by controlling the amount of FC-43 liquid by applying three kinds of insertion techniques, namely dropping, spraying, and evaporation. In the cases of concave and convex imprinted patterns on a 460-nm-thick PMMA film, the defective moldings processes resulting in capillary bridges and bubbles defects were addressed. Among the FC-43 insertion techniques, in case of evaporation method, only a limited amount of inserted FC-43 was left behind, that resulted in the formation of some very small-sized capillary bridges and bubble defects. These results showed that in case of negative molds, complete filling can be achieved if air could be completely replaced by FC-43 which can be done by minimizing the amount of FC-43 liquid.

Heterozygous Mutations in DNA Repair Genes and Hereditary Breast Cancer: A Question of Power

Heterozygous Mutations in DNA Repair Genes and Hereditary Breast Cancer: A Question of Power

소구경 튜브 결함 형태에 따른 유도초음파 신호 해석 특성에 관한 연구

Abstract Currently domestic thermal and nuclear power plants are comprised of many type's condenser and steam generator tubes to produce the electricity of good quality. There are some methods to inspect these tubes in the event that several defects were discovered in these facilities. Among many non-destructive methods, we used guided wave to inspect the soundness of tubes, because this method is very fast to detect the defect and very simple to install the equipment and also, can inspect up to the long range at a fixed point. Also, this method has a drawback that does not detect a very small size defect. So, we made an effort to overcome this drawback through the experimentation and signal analysis according to the size and shape of the defect through the manufacture of various artificial cracks capable to generate within the small size tube in the study and we anticipate that these detect limits can be overcome along with the development of the signal processing and manufacturing technology of the sensor for the inspection.

Crystal structure and melting behavior of homo-polypropylene and heterophasic ethylene–propylene copolymer after long time heat treatment

The homo-polypropylenes and heterophasic ethylene–propylene copolymers (EP-HECO) were prepared by the non-isothermal and isothermal crystallization methods. The crystal structure and crystal phase were detected by the wide-angle X-ray diffraction (WAXD). The morphology of the spherulite growth process was observed under a polarized optical microscope (POM) with a hot stage. The melting behavior was performed by the differential scanning calorimetry (DSC). It was found that the restricted ethylene segment in the long propylene sequences could act as a heterogeneous nucleating agent of β phase only when the crystallization temperature was very high. PP with long molecular chain had more polymer sequences entering crystal lattice to form large lamellar thickness. Nucleation and spherulitic growth occurred at the same time. Both the final spherulite size and the crystallinity of iPP were related to the melt flow rate. When samples crystallized isothermally at a very high temperature, shorter molecular chain would crystallize into some small-size defect crystals, and this resulted in a multiple melting behavior in the DSC endotherm.

Design-Aware Mask Inspection

Mask inspection has become a major bottleneck in the manufacturing flow taking up as much as 40% of the total mask manufacturing time. In this paper, we explore techniques to improve the reticle inspection flow by increasing its design awareness. We develop an algorithm to locate nonfunctional features in a postoptical proximity correction layout without using any design information. Using this, and the timing information of the design (if available), the smallest defect size that could cause the design to fail is assigned to each reticle feature. The criticality of various reticle features is then used to partition the reticle such that each partition is inspected at a different pixel size and sensitivity so that the false and nuisance defect count is reduced without missing any critical defect. We also develop an analytical model to estimate the false and nuisance defect count. Using those models, our simulation results show that this design-aware mask inspection can reduce the false and nuisance defect count for a critical polysilicon layer from 80 defects down to 49 defects, leading to substantial reduction in defect review load. We also develop a model to estimate first pass yield (FPY) and show that our method can improve the FPY for a polysilicon layer from 11% to 30%. Apart from the polysilicon layer, the potential benefit of this approach is analyzed for active, contact and all the metal/via layers.

Erosion Resistance of Chromium–Manganese Iron Alloy Cast in Metal and Sand Moulds: PLS and DBAR Studies

The wear-resistant high chromium (Cr: 16–19 %) iron alloyed with 5 % and 10 % manganese (Mn) was produced in metal and sand moulds by induction melting technique. The erosion resistance, hardness and microstructure were evaluated both in the as-cast and heat, treated conditions. The advanced nondestructive test (NDT) methods, namely Positron Lifetime Spectroscopy (PLS) and Doppler Broadening annihilation radiation (DBAR) studies, using variable energy positron beam were made use of to study the infl uence of metallurgical parameters on the defect sensitivity in the bulk and surface of the alloy. The data reveals that as the mould type is changed from metal to sand, the hardness decreases irrespective of the sample condition (i.e. as-cast or heat treated), whereas the erosion volume loss shows an increasing trend. The light and scanning electron microscopies give good support to these data fi ndings. It is observed that faster the cooling rate (metal mould), fi ner is the carbide size precipitation on the surface of the sample. The PLS data reveals that the defect size and its concentration are higher for sand mould alloy compared to metal mould. Reasons for lower erosion loss and fewer defects of smaller sizes in metal mould are attributed to faster heat transfer in the metal mould compared to the sand mould. Further, heat treatment of the samples yielded spherodization of carbides in the matrix and some of the defects seem to have been annealed out leaving only fewer defects of smaller size in the alloy. The S-parameter profi les of 10 % Mn both in AC and HT samples are almost identical indicating near absence of any modifi cation of defect structure near the surface following heat treatment in 10 % Mn sample, while 5 % Mn samples exhibit less defect concentration both at the surface as well as in bulk which agrees with the PLS results. Hence, the 5 % Mn bearing metal mould sample in the heat-treated condition is preferred choice as it shows higher hardness, lower erosion loss as well as least defect concentration with smaller defect sizes. Based on this investigation, a good correlation among erosion loss, DBA and PLS data has emerged.