Neck Zone Research Articles

An Enhanced Approach for High-Strain Plasticity in Flat Anisotropic Specimens with Progressively Distorting Neck Sections

An Enhanced Approach for High-Strain Plasticity in Flat Anisotropic Specimens with Progressively Distorting Neck Sections

Digital Image Correlation Analysis of Uniform Deformation and Necking in Solid‐State Welded Nanocrystalline Aluminum via High‐Pressure Torsion

Solid‐state welding of Al 1043 sheets was achieved via high‐pressure torsion (HPT) processing to produce bulk nanostructured Al disks. A homogeneous nanostructure without segregation was observed, with grain sizes of ∽430‐470 nm. Miniature tensile testing, coupled with the digital image correlation (DIC) technique, was employed to determine the room‐temperature tensile deformation behavior, particularly the non‐uniform behavior with necking, of the HPT‐bonded ultrafine‐grained (UFG) aluminum, comparing it with annealed coarse‐grained counterpart. The HPT‐bonded UFG Al exhibited a large fraction of post‐necking strain, which is supported by the estimated high strain rate sensitivity value of m = 0.085, suggesting the delay of local necking leading to tensile fracture. Detailed DIC analysis revealed prolonged diffuse necking, thus delaying local necking, in the HPT‐bonded UFG Al, while the annealed samples show high fractions of local necking during the non‐uniform deformation. Moreover, the DIC data illustrated that local necking predominantly occurred at a limited neck zone, maintaining a plateau strain distribution at the out‐of‐neck zone throughout necking deformation towards tensile failure for both annealed and UFG aluminum. The DIC method offers an alternative means to demonstrate the transition in necking behaviors of materials by estimating the plastic lateral contraction exponent.This article is protected by copyright. All rights reserved.

Salivary gland secretory carcinoma presenting as a cervical soft tissue mass: a case report

BackgroundSecretory carcinoma (SC) has been described as a distinct salivary gland tumor in the fourth edition of the World Health Organization (WHO) classification of head and neck tumors. SC is generally considered as a slow-growing low-grade malignant tumor, while several cases have been reported with high-grade features, and even metastases in the literature up until now. In this article, a soft tissue SC case is discussed with high-grade microscopic features and neural invasion. A review of the salivary gland SC cases with aggressive behavior is also debated.Case presentationA 65-year-old Caucasian man presented with a left neck mass for the past six months. The imaging studies demonstrated a very large cystic cervical mass (46 × 23 mm) with papillary projections in the anterolateral aspect of the left neck zone Vb. He underwent left radical neck dissection (level I-V) and was followed up for 12 months with the diagnosis of Secretory carcinoma.ConclusionAlthough SC generally has a good outcome, multiple recurrences and unusual metastases may occur, which should be considered by either the pathologists or clinicians.

Differences in the Occurrence of Cell Wall Components between Distinct Cell Types in Glands of Drosophyllum lusitanicum.

Carnivorous plants are mixotrophs that have developed the ability to lure, trap, and digest small organisms and utilize components of the digested bodies. Leaves of Drosophyllum lusitanicum have two kinds of glands (emergences): stalked mucilage glands and sessile digestive glands. The stalked mucilage glands perform the primary role in prey lure and trapping. Apart from their role in carnivory, they absorb water condensed from oceanic fog; thus, plants can survive in arid conditions. To better understand the function of carnivorous plant emergences, the molecular composition of their cell walls was investigated using immunocytochemical methods. In this research, Drosophyllum lusitanicum was used as a study system to determine whether cell wall immunocytochemistry differs between the mucilage and digestive glands of other carnivorous plant species. Light and electron microscopy were used to observe gland structure. Fluorescence microscopy revealed the localization of carbohydrate epitopes associated with the major cell wall polysaccharides and glycoproteins. The mucilage gland (emergence) consists of a glandular head, a connecting neck zone, and stalk. The gland head is formed by an outer and inner layer of glandular (secretory) cells and supported by a layer of endodermoid (barrier) cells. The endodermoid cells have contact with a core of spongy tracheids with spiral-shaped thickenings. Lateral tracheids are surrounded by epidermal and parenchymal neck cells. Different patterns of cell wall components were found in the various cell types of the glands. Cell walls of glandular cells generally are poor in both low and highly esterified homogalacturonans (HGs) but enriched with hemicelluloses. Cell walls of inner glandular cells are especially rich in arabinogalactan proteins (AGPs). The cell wall ingrowths in glandular cells are significantly enriched with hemicelluloses and AGPs. In the case of cell wall components, the glandular cells of Drosophyllum lusitanicum mucilage glands are similar to the glandular cells of the digestive glands of Aldrovanda vesiculosa and Dionaea muscipula.

Characteristics of ammonia-hydrogen nonpremixed bluff-body-stabilized flames

The combustion of ammonia (NH3) has received much attention over the last few years due to challenges associated with its low reactivity and the emission of nitric oxides. One way to improve the reactivity of NH3 is to blend it with (H2/N2) mixture as the product of its dissociation, before introducing it into energy systems. In this study, experimental measurements were carried out on nonpremixed bluff-body stabilized flames to better understand the flame and emission characteristics of NH3/H2/N2 flames. Four fuel mixtures at different NH3 and (H2/N2) ratios were investigated to represent different levels of ammonia cracking. Photography, planar laser-induced fluorescence of OH, thermocouples, and gas analysis techniques were used to understand flame features, reaction zone characteristics, NO, and NH3 concentration within the flame and at the exhaust. It was observed that a decrease in NH3 ratio in the mixtures resulted in longer and more stable flame with reduced thermal radiation as compared to NH3-rich fuel blends. For the highest NH3 blend studied, the flames exhibit extinction and re-ignition in the neck zone, as evidenced by OH-planar images and temperature profiles. As the H2/N2 ratio in the fuel mixture is increased, while keeping the Re constant, the momentum flux ratio (jet/co-flow) also increased resulting in a fuel-lean recirculation zone (RZ), and a shift in the maximum temperature and OH region from the outer shear layer to the inner layer next to the central jet. At levels of NH3 in the fuel mixture above 50% by volume, unburned ammonia slips through the flame and into the exhaust, and the subsequent reburn mechanism resulted in reduced NO emission. CFD simulations using Reynolds-averaged Navier-Stokes (RANS) and the flamelet–progress-variable submodel were conducted and compared with the experimental results. The CFD results helped to qualitatively describe and further explain what was observed in the experiment including the flame appearance, mixing field, and the reaction zone location in the tested flames.

The Anion Channel TMEM16a/Ano1 Modulates CFTR Activity, but Does Not Function as an Apical Anion Channel in Colonic Epithelium from Cystic Fibrosis Patients and Healthy Individuals.

Studies in human colonic cell lines and murine intestine suggest the presence of a Ca2+-activated anion channel, presumably TMEM16a. Is there a potential for fluid secretion in patients with severe cystic fibrosis transmembrane conductance regulator (CFTR) mutations by activating this alternative pathway? Two-dimensional nondifferentiated colonoid-myofibroblast cocultures resembling transit amplifying/progenitor (TA/PE) cells, as well as differentiated monolayer (DM) cultures resembling near-surface cells, were established from both healthy controls (HLs) and patients with severe functional defects in the CFTR gene (PwCF). F508del mutant and CFTR knockout (null) mice ileal and colonic mucosa was also studied. HL TA/PE monolayers displayed a robust short-circuit current response (ΔIeq) to UTP (100 µM), forskolin (Fsk, 10 µM) and carbachol (CCH, 100 µM), while ΔIeq was much smaller in differentiated monolayers. The selective TMEM16a inhibitor Ani9 (up to 30 µM) did not alter the response to luminal UTP, significantly decreased Fsk-induced ΔIeq, and significantly increased CCH-induced ΔIeq in HL TA/PE colonoid monolayers. The PwCF TA/PE and the PwCF differentiated monolayers displayed negligible agonist-induced ΔIeq, without a significant effect of Ani9. When TMEM16a was localized in intracellular structures, a staining in the apical membrane was not detected. TMEM16a is highly expressed in human colonoid monolayers resembling transit amplifying cells of the colonic cryptal neck zone, from both HL and PwCF. While it may play a role in modulating agonist-induced CFTR-mediated anion currents, it is not localized in the apical membrane, and it has no function as an apical anion channel in cystic fibrosis (CF) and healthy human colonic epithelium.

The 2D and 3D MR arthrographic description of aponeurotic expansion of supraspinatus tendon and biceps tendon anomaly in a large patient cohort.

To describe the aponeurotic expansion of supraspinatus tendon (AEST) and biceps tendon abnormalities with magnetic resonance (MR) arthrographic examinations and determine their prevalence in patients, we performed a high-resolution 3D direct MR arthrography. This was a retrospective study of 700 shoulder MR arthrograms performed between May 2010 and January 2022. Extension in the coronal plane of an AEST on 3D fat-suppressed T1-weighted volumetric interpolated breath-hold examination (VIBE) MR arthrography was identified. Based on its morphology, the AEST on MR arthrography was divided into four subtypes: absence of tendinous thickness in the bicipital synovial surface or intra-synovial tendon-like structure in the bicipital groove, thin and flat tendinous thickness ≥1 mm of bicipital synovium, oval tendinous structure less than half the size of the adjacent biceps tendon, oval tendinous structure more than half the size of the adjacent biceps tendon, and oval tendinous structure larger than the adjacent biceps tendon. Based on its origin and termination, aponeurotic expansions can be divided into three subtypes: proximal pulley zone, middle humeral neck zone, and distal myotendinous junction zone. Association with the biceps synovium of the AEST was categorized into three types: intra-synovial, extra-synovial, and trans-synovial. An AEST in the anterior shoulder joint in 3D VIBE MR arthrography images was identified in 63 (9%) of 700 arthrograms. The most common arthrographic type of AEST was type 1-this was detected in 39 of 63 patients. The most common course type of the AEST was anteriorly midline. The most common distal insertion type was at the tenosynovial sheath of the long head of the biceps tendon (LHBT) in the middle humeral neck zone-this was detected in 31 of 63 patients. There were only 10 MR arthrograms biceps tendon abnormality, including 4 biceps agenesis and 6 split ruptures. A 2D and high-resolution 3D MR arthrography can demonstrate the anatomical detail around the bicipital groove and facilitate the differentiation between a biceps tendon anomaly and an AEST. On high-resolution 3D MR arthrographic images, the AEST tends to be in the anterior midline and anteromedial portions of the biceps synovium with intra-synovial, extra-synovial, and trans-synovial courses and its three different insertion types.

Early onset, development and histological features of gastric signet-ring cell carcinoma.

To explore the early onset, development and histological features of gastric signet-ring cell carcinoma (SRCC). Three hundred and sixty-two patients with differentiated adenocarcinoma with signet-ring cells were enrolled. Histomorphological and immunohistochemical features and patterns of the specimens were observed in detail. Infection of the gastric mucosa, especially by Helicobacter pylori, can cause massive cell proliferation and transformation in the deep gastric foveola, the isthmus of the gastric gland, and the proliferative zone of the upper neck of the gland. Signet-ring-like heterocysts monoclonally proliferated after the redifferentiation and reproliferation, extending horizontally along the gastric foveola. Gastric foveolar-type SRCC grew infiltratively into the lamina propria of the mucosa and the submucosa, signet-ring cells could differentiate into undifferentiated adenocarcinoma with signet-ring cell differentiation, mucinous adenocarcinoma with signet-ring cell differentiation, gastric adenocarcinoma with signet-ring cell differentiation, and fundus gland adenocarcinoma with signet-ring cell differentiation. Early SRCC developed from the proliferative zones of the fundus of the gastric foveola and the neck of the gastric gland, growing horizontally along the gastric foveola. It developed into gastric adenocarcinoma with signet-ring cell differentiation after reproliferation and retransformation in the mucosa.

Bipolar Cautery in Aneurysms: Effective but Underutilised Technique

ABSTRACT Background: Bipolar cautery for aneurysms is an effective technique, described in the literature about 50 years back by Yasargil, however, there is an inadequacy of articles highlighting the technique. Materials and Methods: Operative videos of aneurysm surgeries were analysed to select the videos/photographs which can help readers to understand the technical nuances of using bipolar cautery during aneurysm surgeries. Cautery was used after the completion of sharp dissection around the neck and demarcation of proximal and distal vessels in non-giant aneurysms. Cautery setting was kept around 10%–20% of the maximum. Blunt tip forceps were used with continuous irrigation. A shaft instead of the tip of the cautery was used. Results: Bipolar cautery resulted in the shrinkage of the wall of the aneurysm. It had a similar effect on the neck, fundus or transition zone between the neck and fundus. It helped in controlling the bleeding from the fundus even during intraoperative rupture of the aneurysms. Even the flimsy wall of the fundus shrunk, which prevented their rupture during dissection. It was very useful to make giant aneurysm fundus shrink to a smaller size providing space for dissection. The wide neck could be modified to a desirable shape for easier clip applications. Conclusion: Fear of intraoperative rupture by cautery appears misconceived. It causes shrinkage of the wall of the aneurysm, can stop bleeding from the fundus and can change the shape of the neck fundus, which helps clipping the aneurysms easily.

Dyke or pipe? Contributions of magnetic fabrics to the reconstruction of the geometry of an eroded subvolcanic body (Cadí basin, Pyrenees)

The reconstruction of the geometry of igneous bodies in inverted basins is often a difficult task, because most of their volume can be either below or above the topographic surface. Indirect methods, such as the determination of their internal fabric can give clues to constrain geometrical reconstructions. The Sant Salvador intrusion, located in the Late Carboniferous-Permian Cadí basin (Central-Eastern Pyrenees), is a good example for testing the application of magnetic fabrics to shallow igneous bodies because of (i) its characteristics in terms of crystal composition/orientation, showing a homogeneous petrofabric controlled by plagioclase crystals 0.4 mm in size, (ii) its good, though partial, preservation, (iii) its position in the stratigraphical succession, between volcaniclastic sediments and unconformably overlying red beds, and (iv) the many unknown factors related to the intrusion, including the geometry of the body and its depth and the amount of erosion after intrusion. Furthermore, the Sant Salvador intrusion provides opportunity for checking the correspondence between the petrofabric and the magnetic fabrics when the magnetic carriers of susceptibility (with an average value of 5217·10−6 SI) are mainly ferromagnetic. In this case the main magnetic carriers are magnetite and also hematite, the latter resulting from oxidation processes at the paleosurface. The results of Anisotropy of Magnetic Susceptibility show a bimodality in the K1 disposition after bedding restitution: vertical in the deeper areas of the intrusion and subhorizontal, E-W, in the uppermost stratigraphic positions with an intermediate necking zone in which transition from vertical to horizontal flow is interpreted to occur. Bands deflecting the mineral foliation at the micro scale have also a tectonic or thermal origin but do not seem to interfere with the magnetic ellipsoid axes. Columnar jointing is interpreted to be parallel to the long axis of the intrusion (and therefore to magma flow, and perpendicular to the paleosurface. All these features indicate that the Sant Salvador intrusion can be interpreted as a subvertical pipe feeding a sill that was eroded before the sedimentation of the overlying red beds.

Mechanical strength and nature of lithospheric deformation beneath the rifted sedimentary basins of the east India passive margin

The study of gravity signatures corresponding to sediment load over the passive margins is helpful to constrain the mechanical properties of continental rift systems as well as the adjacent ocean basins. Seismic reflection, free-air gravity and well information from the East India Passive Margin (EIPM) are investigated through spectral approach and 2D process-oriented gravity modelling for quantifying effective elastic plate thickness (Te) to understand the rift mechanisms and the sedimentary basins evolution. The characteristics of lithosphere within the major structural domains along the margin are quite variable. A narrow necking zone (40 km) in the southern segment, and approximately a 70 km hyper-thinned and exhumed domains are inferred in the central segment, while a narrow hyper-thinned domain (30–35 km) is observed in the northern segment of the margin. The southern segment of EIPM, adjacent to Southern Granulite Terrain has low Te values ranging from 5 to 10 km. The segment in the central margin, offshore Dharwar Craton has moderate Te values of 15–20 km. And the northern segment adjacent to onshore Eastern Ghats Mobile Belt has relatively high mechanical strength with Te values ranging from 25 to 35 km. The pattern of Te values and extent of major structural domains along the margin indicates that the southern, central and northern segments evolved as three different modes of rifting such as transform, hyperextended and hypoextended, respectively. In the oceanic domain, the lithospheric strength broadly increases with age following the thermal induced cooling plate model (600 °C isotherm). The thick sedimentary basin of the Bay of Bengal had attained the high value of elastic thickness (Te > 45 km) in the last 23 Myrs. The significant rheological strengthening of the oceanic lithosphere may be attribute to the following reasons: 1) increase in shear-wave velocity anomaly at a depth of 150 km and upper mantle density, 2) change in plate curvature caused by excessive deposition of Bengal Fan sediments in the deep ocean basins and subduction of oceanic plate under the Eurasian plate near the Bengal Fan and 3) modification of stress state of the lithosphere as a convergent interaction of the Indian plate with SE Asia.

Effect of H2 addition on the local extinction, flame structure, and flow field hydrodynamics in non-premixed bluff body stabilized flames

We examined the effect of hydrogen (H2) enrichment on the primary fuel methane (CH4) in a canonical non-premixed bluff-body stabilized burner operating under typical central jet-dominated flame mode. In the chosen mode of operation, globally, the flow field and flame feature three important successive spatial zones: the recirculation zone, the neck zone, and the jet-like flame zone. The flame is exposed to a higher stretch rate in the neck zone in such a configuration and eventually undergoes local extinction. Such local extinction and subsequent re-ignition/reconnection of broken flame branches have substantial implications for the hydrodynamic instability of the coaxial annular air shear layer. It is well known that H2 addition increases the flame extinction strain rate (κext) and thus alters the local extinction phenomenon. To understand this, we performed experiments at 0%, 10%, 20%, 30%, 50%, 80%, and 100% hydrogen proportion in the H2-CH4 blend. High repetition rate (5 kHz) Particle Image Velocimetry and OH Planar Laser Induced Fluorescence (PLIF) measurements are simultaneously implemented to gain quantitative insight into the flow field and flame structure. A detailed analysis performed over the instantaneous OH–PLIF datasets reveals the absence of local extinctions in flames with H2 enrichment >30% due to an increased extinction strain rate (κext). Furthermore, it is found that H2 enrichment plays a significant role in the reconnection/re-ignition of the broken flame branches formed during the local extinction. For instance, a high reconnection probability is observed in flames with an H2 addition of ≥20%. Consequently, variations in the mean reaction zone height are witnessed for different H2 enrichment levels. Further analysis of the influence of variation in reaction zone height on flow field hydrodynamics is explored using Proper Orthogonal Decomposition (POD) and Continuous Wavelet Transform (CWT). The results obtained from POD and CWT indicated the suppression of vortex shedding at the annular air shear layer for H2 addition greater than 20% and irregular wrinkling of flame fronts. Thus, they quantified the beneficial effect of H2 addition in turbulent flame stabilization.

Soot structure and flow characteristics in turbulent non-premixed methane flames stabilised on a bluff-body

The soot properties of methane in turbulent regimes are not well characterised but are highly desirable. Methane is the main constituent of natural gas that is broadly used in many industrial combustors. Investigation of turbulent methane flames under well-defined boundary conditions is therefore useful for interpreting soot formation in practical burners and can be used for further model development. This study presents a joint experimental and numerical study of a series of turbulent non-premixed bluff-body flames fuelled with pure methane for three values of the momentum flux ratio of fuel jet to co-flowing air. Soot volume fraction (SVF) and flowfield are measured simultaneously using planar laser-induced incandescence (P-LII) and 2D-polarised particle image velocimetry (P-PIV). Additionally, time-averaged temperature, mixture fraction, OH and C2H2 concentrations are estimated numerically using RANS models. The global flame structure for all three flames features a recirculation zone with a double-vortex structure, a jet-propagating zone, and a neck zone connecting the two regions. The soot distribution within the recirculation zone shows clear distinct features, which is attributed to the mean mixture fraction distribution in this zone. Increasing the momentum flux ratio shifts the location of the mean stoichiometric mixture fraction to the rich inner vortex core, leading to a distinct peak of the total integrated soot in the inner vortex of the recirculation zone that is not observed in other cases. Also, it is deduced that the soot inception starts earlier in the recirculation zone for the flame with the highest momentum flux ratio and in the jet zone for the other two flames. Much higher soot concentration and lower intermittency are found with ethylene-based flames stabilised on the same burner and with the same operating conditions. In addition, the study has generated a database of soot and flowfield results, which can be helpful for future model validations.

Kite String Injures During Makar Sankranti Festival

Introduction: Kite flying is a colourful festival; it is unfortunately associated with a significant number of incising injuries of neck and face caused by the kite string (Manja). The emergency departments report a large number of patients with such injuries during this festival. Materials And Methods: Patients presented to the Emergency Department at Civil Hospital, Gandhinagar on 14th and 15th January with neck and face injury caused by contact with kite string were included in study. After careful assessment (primary and secondary survey) patients were classified as Superficial (Laceration limited to the skin and subcutaneous tissue) or Deep injury (breach of the platysma, and damage to muscles, thyroid gland, neurovascular or airway involvement). Results: 20 patients were included in study. Out of which 18 were males and 2 were females. Amongst 18 males 2 were children. Two patients wearing a helmet suffered an injury to the nose. The neck zones involved in the injury, 5 cases involved zone I injury, 9 cases in zone II, 4 cases were in zone III and the remaining 2 had the nasal injury. Conclusion: From this study we conclude that kite string injury lead to serious damage to local tissues. Using protective measures can reduce the incidence and severity of injuries.

The Mechanical Characteristics of the Neck Zone for a PEMFC Stack

Generally, the unit cell in a proton exchange membrane fuel cell (PEMFC) stack is divided into different zones according to the characteristics of the bipolar plate. There is a zone that has been neglected, which we define as the “neck zone” for the first time in this work. Uneven stress and deformation are prone to appearing in the neck zone due to its unique structure. A three-dimensional finite element model was applied to study the influence of the membrane electrode assembly (MEA) frame materials on the mechanical characteristics of the neck zone. In addition, the sealing and the water–gas transport performances of the neck zone were evaluated via the stress fluctuation and deformation. It was found that even with the commercial polyethylene naphthalate (PEN) frame, a leak point would be generated at the region with the lowest stress, reducing the performance and even causing safety hazards. The invasion rate was proposed to assess the water–gas transport ability. When an inappropriate frame material was adopted, the invasion rate went up to 32.4%, severely hindering the water and the air transport. It was concluded that MEA frames with a higher elastic modulus and thickness are preferred for the neck zone to obtain a high property of sealing and water–gas transport.

Crust necking of the northeastern South China Sea: Insights from deep seismic data

During rifting, continental crust necks, leading to significant thickness reduction in a few tens of kilometres. However, deformations associated with the necking process remain elusive due to few outcrop examples and a lack of seismic data coverage that clearly images crustal architecture at depth. Here we use deep, high-resolution seismic data across a well-developed necking zone in the northeastern South China Sea passive margin to show the structural style associated with the crustal necking. Seismic stratigraphy in the necking domain can be divided into pre-, syn- and post-rift sequences based on the nature of sequence-bounding unconformities and their relation with faults. Seismic expression of continental crust exhibits two types of reflection characteristics – homogeneous upper crust and layered lower crust. The necking domain shows significant thinning that reduced its thickness from ~30 km to less than over 10 km in a distance of about ~50 km and is characterised by seaward removal of layered lower crust, while the homogeneous upper crust thickness remains largely unchanged in thickness. The necking domain is bounded by inner and outer breakaway complexes that define a portion of flexed crust. Crustal flexure is evidenced by progressive tilting of the necking domain that gradually increases the pre-rift sequence dip from 0° to 10°. Within the tilted necking domain, densely-spaced, landward-dipping minor faults and fractures are organised in a domino configuration, implying a top-to-the-continent movement and a simple shear deformation of the whole continental crust. We suggest that the flexed necking domain could be home to fractured reservoir providing that it is effectively sealed by post-rift sequences.

Forming limit of AZ31B magnesium alloy under in-plane complex biaxial loading paths with cruciform specimens

This paper focused on the forming limit curves (FLC) of the AZ31B magnesium alloy sheet metal under different complex loading paths in-plane. Compared with simple loading paths, the study of forming limit of sheet metal under complex loading paths was more practical. In this study, biaxial tensile test of the cruciform specimen was utilized to acquire the FLC after the cruciform specimen was subjected to uniaxial pre-tensile process along rolling direction, which experimentally characterize the forming limits under different pre-strain values of 1.15%, 2.34%, 4.0%, and 5.4%. Subsequently, based on the constitutive model, Hill48 yield criterion and shear failure criterion, the theoretical FLCs of AZ31B magnesium alloy sheet metal was be calculated. Meanwhile, the normal biaxial tensile tests were also simulated by Abaqus to obtain the limit strains by Finite Element Analysis (FEA). Extracting limit strains from the fracture region in FEA model when the first derivative of the strain difference with respect to time reached the maximum value between the first principal strain of necked element and the first principal strain of the element adjacent to the necked zone. As a result, the experimental FLCs was qualitatively consistent with the result of theoretical model and FEA model. In addition, the FLCs of AZ31B magnesium alloy sheet moved to the upper left of forming limit diagram with the increase of the pre-strain, which indicated that the pre-strain process along the rolling direction could significantly improve the formability of the sheet metal.

ПОЛИМОРФИЗМ BSMI ГЕНА РЕЦЕПТОРА ВИТАМИНА D И ЭФФЕКТИВНОСТЬ ЛЕЧЕНИЯ ПОСТМЕНОПАУЗАЛЬНОГО ОСТЕОПОРОЗА ИБАНДРОНОВОЙ КИСЛОТОЙ

An assessment of genetic factors influence on ibandronic acid effect in postmenopausal osteoporosis treatment can significantly bring us closer to the practical use of this results in prognostic genetics and personalized medicine. The aim was the study of associations between 283 A>G (BsmI, rs1544410) polymorphisms of vitamin D receptor gene (VDR) and ibandronic acid efficacy in postmenopausal osteoporosis treatment.
 117 women with postmenopausal osteoporosis were examined through treatment dynamics. A 12-month therapy course included the use of ibandronic acid according to standard regimen. Evaluation of treatment effectiveness was carried out by changes (%) in bone mineral density (BMD) separately for each area by dual- energy X-ray absorptiometry. Real-time PCR was used to determine VDR gene rs1544410 polymorphism.
 It was found that for 12 months ibandronate use caused significant (p<0.001) BMD increase. BMD increase ranged from 2.71±0.53% in left femoral neck zone to 4.63±0.53% in the L1-L4 lumbar vertebrae. The treatment outcome did not depend (p>0.05) on age, height, weight, body mass index, and postmenopause duration. GG genotype of rs1544410 polymorphism was associated with lower BMD growth rate in L1-L4 lumbar vertebrae (p=0.036).
 Screening of women with postmenopausal osteoporosis for polymorphic variants of VDR gene (rs1544410) before antiresorptive therapy with ibandronic acid may be appropriate to predict the effect and individualize treatment and prophylactic measures. The obtained results can contribute to more complete understanding of osteoporosis pharmacogenetics

Modification of ultrasonic transducers to study crack propagation in vinyl polymers, supported by SEM technique

AbstractDetecting defects in various industrial products remains a challenging task in the industry. Researchers are constantly working to improve detection techniques and tools for various defects, particularly cracks. Many industrial structures suffer from cracks. The selection of a suitable technique and/or tool is based upon the tested structures and the accuracy of the technique and/or tool. The work's novelty is the development of a fully accurate, simple, and safe ultrasonic tool for precisely scanning cracks. A pen‐shaped cone was added to the ultrasonic transducers to improve their performance. Different crosshead speeds and annealing techniques were used to cause cracks on medium density polyethylene (MDPE) and poly‐methyl‐methacrylate (PMMA) polymer plates with specific dimensions. Cone reduced the front diameter of the transducers from 12 to 2 mm (cone tip diameter). It improved the transducers by giving them new properties such as a small near field, a collimated beam, high sensitivity, and high wave reflection. The modified transducers tracked the cracks at discrete sequential sites, where the ultrasonic velocity was measured to determine the crack speed, critical crack speed, dynamic stress intensity factor, and crack branching phenomenon. Additionally, ultrasonic attenuation was measured in order to accurately determine crack growth behavior, the crack's neck zone, and the crack growth dependency on both plate thickness and annealing. Scanning electron microscope (SEM) images revealed crack propagation in polymer plates. The results of ultrasonic testing and SEM evaluations were consistent. This guaranteed that the modified transducers could scan cracks accurately.

On The Relationship Between H2 Addition, Local Extinction And Hydrodynamic Instability In Non-Premixed Bluff-Body Stabilized Flames

In the race for decarbonization of the power sector, H2 is found to be a better candidate as it can be readily produced in large scales from renewables (e.g. wind and solar energy). Nevertheless, the difference in the thermophysical properties of H2 in comparison to the conventional fuels possesses additional operational challenges. For instance, although the high flame speed together with a wide flammability range offer improved flame stabilization, however, it intensifies the risk of flashback. Besides, the increased strain resistance due to H2 enrichment is expected to alter the flame shape significantly. Hence, it is apparent that the widespread implementation of H2 across various practical systems needs a thorough understanding of the various physical mechanisms. In this context, we examined the effect of hydrogen (H2) enrichment to methane (CH4) in a non-premixed bluff-body stabilized burner operating under typical central jet dominated flame mode. In the chosen mode of operation, globally, the flow field and flame feature three important successive spatial regions, namely, recirculation zone, neck zone and jet-like flame zone. In such configuration, the flame is exposed to a higher stretch rate in the neck zone and eventually undergoes local extinction. Such local extinction and subsequent re-ignition of broken flame branches have strong implications over the hydrodynamic instability of the coaxial annular air shear layer. It is well known that H2 addition increases the flame extinction strain rate and thus alters the local extinction phenomenon. To understand this phenomenon, we performed experiments at 10%, 20 %, 30% and 50 % hydrogen proportion in (H2-CH4) blend. High repetition rate (5 KHz) PIV and OH PLIF measurements are performed simultaneously to perceive the quantitative insights. The results obtained from POD and 1D wavelet transform indicated the suppression of vortex shedding at the annular air shear layer for H2 addition greater than 20 %, and thus quantified the beneficial effect of H2 addition in turbulent flame stabilization.