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Microcrystalline cast stone is a silicate inorganic nonmetallic material prepared via a melting–casting–crystallization process using slag as the main raw material and appropriate nucleating, quenching, and tempering agents. However, crystallization of the microcrystalline cast stone causes overall shrinkage, producing defects such as holes on the surface and inside and affecting the quality and yield. In this work, the effect of quartz-sand addition on the formation of voids in microcrystalline cast stone prepared from blast-furnace slag is studied. The theoretical composition, phase transformation, and microstructure of microcrystalline cast stone are analyzed through FactSage thermodynamic calculations, X-ray diffraction, and scanning electron microscopy. The results show that the main crystal phases in the microcrystalline cast stone are gehlenite and akermanite for 5, 7, 8, and 10 % quartz-sand addition. When the amount of quartz sand added is 8 %, the overall shrinkage rate of the ordinary augite phase is 16 %. The maximum amount of dicalcium silicate is formed, filling the holes on the surface and inside and inhibiting the formation of holes. The crystal morphology is snowflake-like and the crystal connections are dense. The flexural strength reaches a maximum value of 40.08 MPa, which improves the overall performance of the microcrystalline cast stone. The results of this study can provide technical support for improving the yield and quality of microcrystalline cast stone prepared by melting. [Display omitted] [ABSTRACT FROM AUTHOR]

Experiments are conducted to investigate leakage through circular GMB holes overlain and underlain by both tailings with various hole diameters and GMB thicknesses. Finite element analyses are performed to explore the effect of hydraulic conductivities (k) of subgrade (underliner) and tailings above the GMB (overliner) on water head contours dissipation. An analytical solution is developed for predicting leakage through circular GMB hole overlain and underlain by both tailings. Results show that the effect of subgrade on leakage is highly dependent on the ratio of k between the underliner and the overliner. If the ratio >100, no head loss occurs in the subgrade; if the ratio <0.01, all the head loss occurs in the subgrade. With the deposition of fines from overliner into subgrade, a low permeable filter cake is formed on the subgrade surface, notably increasing the impact of underliner on leakage. With the increasing ratio of k between underliner and overliner from 0.01, 0.1, 1, 10, and to 100, the ratio of leakage relative to a highly permeable subgrade increases from 0.01, 0.1, 0.56, 0.93, and to 1. An intimate interface contact can be achieved when the GMB is underlain by silty sand tailings as subgrade (foundation) material. [ABSTRACT FROM AUTHOR]

The article investigates by finite elements the bending stresses around a centre transverse circular hole in straight bars with rectangular or circular cross-section. Four loading conditions are considered, pure bending and three variants of three-point bending (load concentrated on the bar surface above the hole, load directly applied to the hole as uniform pressure, load applied to the hole through a connecting pin). Mostly, the hole diameter is one-third of the section height and one-twentieth of the beam length. Holes of one-fourth and one half of the section on several beam lengths are also investigated for the flat bar in three-point bending to appraise the sensitivity to aspect ratios. The results show that, in all cases, the notch effect is mildly detrimental to the stress distribution and can even be beneficial in comparison with the unperforated bar. This is because the hole increases the stresses around the neutral axis, where the stresses are naturally low, thus taking away stresses from the surface where the bending stresses are naturally highest. The design of pivoted flexural machine elements like levers, yokes and balance arms can take advantage from this evidence. [ABSTRACT FROM AUTHOR]

In image processing, computer vision algorithms are applied to regions bounded by closed contours. These contours are often irregular, poorly defined, and contain holes or unavailable areas inside. A common problem in computational geometry includes finding the k-sided polygon (k-gon) of maximum area or maximum perimeter inscribed within a contour. This paper presents a generic method to obtain user-defined polygons within a region. Users can specify the number k of sides of the polygon to obtain. Additionally, users can also decide whether the calculated polygon should be the largest in area or perimeter. This algorithm produces a polygon or set of polygons that can be used to segment an image, allowing only relevant areas to be processed. In a real-world application, the validity and versatility of the proposed method are demonstrated. In addition, the source code developed in Java and Python is available in a GitHub repository so that researchers can use it freely. [ABSTRACT FROM AUTHOR]

In contrast to the conventional etching that makes nanoparticles rounder and our previous sharpening etching mode that causes serrated edges, here, we developed a new boring etching mode that targets the faces of Au nanoplates to make holes. The critical factors are the pre-incubation step with the ligand 2-mercapto-5-benzimidazolecarboxylic acid (MBIA) and the subsequent removal of excess ligands in the solution. Thus, etching is focused onto the few sites with initial loss of ligands, which cannot be quickly replaced. The choice of ligand MBIA is also of importance, as it carries negative charge and repels each other. Its inability of forming a dense layer probably plays a critical role in the site-selectivity for faces, because ligands at the higher curvature edges and corners are expected to have less repulsion. The etching results from the comproportionation reaction between Au3+ and Au0 in the nanoplates, where Br− coordination to Au and the extra stabilization from cetyltrimethylammonium bromide (CTAB) are essential. We believe that the ability of boring holes is an important tool for future synthetic designs. [ABSTRACT FROM AUTHOR]

Experiments are conducted to investigate the effect of a drainage layer in/below saturated tailings on leakage through a hole of various shapes and sizes in a 2-mm-thick HDPE geomembrane. Three cases: no drainage (Case 1), drainage layer between two layers of tailings (Case 2), and drainage layer below tailings and above the GMB (Case 3) are examined. Analytical solutions predicting leakage through a circular GMB hole overlain by tailings with an internal drainage in (Case 2) and below (Case 3) tailings are developed, and match the experimental and numerical results well. Results show that a drainage layer separated from the GMB by a thin layer of tailings (Case 2) gives leakage slightly greater than if no drainage layer is present, but 3-5 orders of magnitude lower than when the drainage is placed directly over the GMB (Case 3). In Case 3, leakage is dependent on the hydraulic conductivity k of both the drainage and subgrade, and is not affected by the tailings. Unlike Cases 1 and 2 where the subgrade has negligible effect on leakage, a low permeability subgrade with k less than 10% of k for the drainage layer is recommended in Case 3 to minimize leakage through geomembrane defects. • first investigation of the effect of an internal drainage within tailings on leakage through a GMB defect. • first evaluation of where to place the internal drainage in order to minimize leakage through a GMB defect. • first guidance on how to predict leakage through a GMB defect when a drainage is placed at different positions. [ABSTRACT FROM AUTHOR]

We have obtained straight-line-shaped agglomeration grooves of 2~3.5 μm width in the ~60-nm-thick Si thin films by the continuous-wave laser crystallization (CLC) when the laser power is increased above the optimum power to obtain grain boundary-free (GB-free) films. The GB-free CLC is suitable for fabricating monolithic three-dimensional integrations. The grooves are formed in the Si film vertically from the Si surface to the underlying insulating substrate, and a hump of the Si film is generated along the edge of the groove at the retarded side of the scan. In situ observation of the crystal growth shows that the grooves originate from voids, which happen to be generated by agglomeration in the melt zone. The voids move at a constant velocity, Vvoid , within the melt zone. The melt zone moves at the scan velocity, V, to the scan direction. The void velocity, Vvoid , is obtained from the angle of the groove line to the scan direction, and is found to be proportional to V−0.5. [ABSTRACT FROM AUTHOR]

Electrical discharge drilling of blind holes has been a challenging task due to the inherent difficulties in removing debris from the discharging gap. This paper investigates the working mechanism and effects of new stepped electrodes which are used in conjunction with injection flushing in drilling deep blind holes. A series of theoretical simulations and comparative experiments were conducted using cylindrical electrodes and two types of stepped electrodes. Pulse waveforms were captured to analyse the discharge status. Surface topography and machining quality were analysed using scanning electron microscope (SEM) images. The machining performance was evaluated by studying the material removal rate (MRR) and tool wear ratio (TWR). Experiment results show that internal flushing caused the debris to circulate in the machining zone and led to abnormal discharges, disrupting the formation of the plasma channel. The MRR was increased by 75% and 82% when using cylindrical electrodes with pressures of 120 psi and 40 psi, respectively. In contrast, the MRR with injection flushing was about 80% of that without injection flushing when using stepped electrodes. Regardless of the type of electrode, the application of injection flushing resulted in the increase in the maximum effective machining depth. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Current studies on blasting construction of small clear-distance tunnels have not considered the impact of existing tunnel lining defects when establishing safety controls. This paper offers a series of study results based on the blasting project of a new tunnel adjacent to the existing defect Xinling tunnel to thoroughly examine the dynamic response, safety control standards, and measures of the existing defect tunnel. First, structural models were developed to investigate the influence of the presence or absence of specific defects (like lining cracks and cavities behind the lining) on the dynamic response of the current tunnel lining to identify the most unfavorable defect distribution. Then, establish safety control standards for intact linings and those with the most unfavorable defects. Eventually, two types of control measures, single safe charge and reasonable delay time, were studied based on the established safety control standards. In particular, the most adverse position of cracks was the wall facing the explosion, the rise in depth was more unfavorable for vibration response, and the impact of the longitudinal crack was restricted to the vicinity of the crack. While the vault was the most adverse cavity position, the rise in cavity area was more damaging, and the influence range varied with longitudinal cavity length. Moreover, the impact of cracks was mainly evident in the amplification effect of stress at the crack region. In contrast, cavities had varied degrees of ampli- fication effects on the vibration velocity and stress response and a relatively extensive influence range. Safety control research was conducted, when the tunnel was intact, with a right wall crack, a vault cavity, and both vault cavity and crack for this project, the peak particle velocity (PPV) of the safety control standard for vibration velocity was 13, 10, 13, and 8 cm/s, respectively, and the respective single safe charge could be adjusted at 64, 53, 37, and 25 kg. However, the presence of different defects had a relatively negligible effect on the reasonable delay time; 25 ms was recommended for existing tunnel lining with and without the defect. [ABSTRACT FROM AUTHOR]

The design of three-dimensional printing based conformal cooling channels (CCCs) in injection molding holds great significance. Compared to CCCs, conformal cooling (CC) cavity solutions show promise in delivering enhanced cooling performance for plastic products, although they have been underexplored. In this research, CC cavity is designed within the mold geometry, reinforced by body-centered cubic (BCC) lattice structures to enhance mechanical strength. Three distinct BCC lattice variations have been integrated into the CC cavity: the BCC structure, BCC with cubes, and BCC with pillars. The thermal performances of the BCC lattice-added CC cavity are assessed numerically after experimental validation. To provide feasible solutions from viewpoints of thermal performances, various BCC lattice structure thicknesses are analyzed in the range of 0.8–1.2 mm. Thermal simulation outcomes reveal that thicker lattice structures enhance mechanical strength but simultaneously lead to an increase in cooling time. Upon examining all the proposed CC cavity solutions supported by BCC, the cooling times range from 2.2 to 4 s, resulting in a reduction of 38.6% to 66.1% when compared to conventional straight-drilled channels. In contrast to CCCs, CC cavities have the potential to decrease the maximum temperature non-uniformity from 8.5 to 6 K. Nevertheless, the presence of lattice structures in CC cavity solutions results in an elevated pressure drop, reaching 2.8 MPa, whereas the results for CCCs remain below 2.1 MPa. Graphic Abstract [ABSTRACT FROM AUTHOR]

This contribution takes the form of a transcript of a prayer/interview. A prayer is a speech act directed into a void, towards an absence (a hole, so to speak). It 'lays claim to an immediate connection with the Being whose absence fills the world' as Anne Carson writes in reference to the mystics Simone Weil and Marguerite Porete (2005: 177). The aspiration of a prayer, not unlike a spell or curse, is to directly affect something or someone in the real and physical world through an act of speech (Carson 2005: 177). The following text is developed in reference to the three existing books of the writings and teachings of the mystic St. Catherine of Siena. Parts of the text are fictionalized, reassembled and borrow direct and attributed quotes of these books. The script features characters called K, an amalgam of the researcher and the persons, figures and subjects I converse with in my research. K blurs the authorial voice by mingling it with others, in an attempt to flatten the authority of the narrating voice towards polyvocality. Combining the forms of prayer, interview, dialogue, written conversation and play serves to explore and apply different registers of writing that correspond with St. Catherine's chosen forms of communication and to (playfully with a nod to common academic methodologies) investigate the holeyness/brokenness of dialogical speaking voices, the wounded text and a textual approach towards the unsayable/unthinkable. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Almaty Technological University is the property of Almaty Technological University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

SnO2/BiOBr photocatalytic materials were successfully synthesized by hydrothermal method with BiOBr as the precursor. X‐ray diffraction studies confirmed that BiOBr and SnO2 were successfully combined. After characterization, we proposed a possible formation mechanism for SnO2/BiOBr. The degradation experiment showed that the degradation rate of norfloxacin using SnO2/BiOB‐4 reached 85.9 %, which was approximately 50 and 65 percentage points higher than that of pure BiOBr and SnO2, respectively. The reaction rate was 4.3 times that of BiOBr. Based on the analysis of the degradation mechanism, the improved photocatalytic performance may be attributed to the optimized energy band structure resulting from the combination of the two monomers. This promotes the effective separation of photogenerated electrons and holes, leading to the generation of more active substances such as ⋅O2− and h+. As a result, the oxidation capacity is enhanced. [ABSTRACT FROM AUTHOR]

Our critical analysis of Hutchinson's work, expressed in our recent article in the Annalen der Physik, which goes beyond mutual misunderstandings and misrepresentations, is also maintained in light of his Comment. The main reason for the limited yield in structural description is the author's adherence to the BGK method and the associated lack of a nonlinear dispersion relation (NDR). Even with an additional asymptotic constraint, as a supposed replacement for the NDR, the author's theory remains inferior to the pseudo‐potential method. [ABSTRACT FROM AUTHOR]

The efficient cobalt doping of zinc oxide nanoparticles grown by chemical method, with Co2+ substituting the Zn2+ cations, is proved by electron spin resonance spectroscopy for cobalt concentration from 0.01% to 1.00%. The gradual killing of the usual core‐defect signal (g ≈ 1.96) as the Co concentration is increased prevents its ionization by optical excitation from X0 to X−, thus inhibiting the corresponding hole releasing. Consequently, the •CH3 methyl radical is no longer generated on the nanoparticles surface by the photo‐Kolbe reaction h++CH3COO−→•CH3+CO2. It is thus confirmed that the hole involved in the dissociation of surface acetate actually comes from the optically excited core‐defect g = 1.96, and that the number of these defects can be tuned by some very small amount of cobalt impurities. [ABSTRACT FROM AUTHOR]

Hydraulic fracturing is a mainstream technology for unconventional oil and gas reservoirs development all over the world. How to use this technology to achieve high-level oil and gas resource extraction and how to form complex fracture networks as hydrocarbon transportation channels in tight reservoirs, which depends to a large extent on the interaction between hydraulic and pre-existing cracks. For hydraulic fracturing of fractured reservoirs, the impact of natural fractures, perforation direction, stress disturbances, faults and other influencing factors will produce a mixed I&II mode hydraulic fracture. To forecast whether hydraulic fractures cross pre-existing fractures, according to elastic mechanics and fracture mechanics, a stress state of cracks under the combination of tensile (I) and shear (II) is presented. A simple mixed-mode I&II hydraulic fracture's crossing judgment criterion is established, and the propagation of hydraulic fractures after encountering natural fractures is analyzed. The results show that for a given approaching angle there exists a certain range of stress ratio when crossing occurs. Under high approaching angle and large stress ratio, it is likely that hydraulic cracks will go directly through pre-existing cracks. The reinitiated angle is always controlled within the range of approximately 30°C among the main direction of penetration. [ABSTRACT FROM AUTHOR]

This article explores the links between creative imagination and extraction in the Democratic Republic of the Congo (DRC). This question has an undeniable memorial dimension, for extraction, as a crucial point of entry into Congolese historical consciousness, allows for a multi-perspectivist examination of the way in which the memory of the past has been archived, experienced, and (mis) interpreted. As a key term to understand Congo's geopolitical position since colonial times, extraction offers a rich array of tropes and ideas to assess culture from the DRC and the Congolese diaspora. First, I reflect on the notions of extraction and extractivism; secondly, I analyse how they form the basis of Sammy Baloji's multimedia work in Mémoire (2006) and Mémoire/Kolwezi (2014); then, I turn to La Danse du vilain (2020) and Tram 83 (2014) by Fiston Mwanza Mujila, first to assess how extraction is employed in these novels, then to conduct a reflection on 'necropolitics', and reveal little-known aspects of diamond digging during the Mobutu era. I will also show that Baloji's and Mujila's creative trajectories have been enriched by dialogues with Filip De Boeck, the Belgian social anthropologist and specialist of the DRC. [ABSTRACT FROM AUTHOR]

The primary focus of this paper is to investigate the application of ANSYS Workbench 19.2 software's advanced feature, known as Separating Morphing and Adaptive Remeshing Technology (SMART), in simulating the growth of cracks within structures that incorporate holes. Holes are strategically utilized as crack arrestors in engineering structures to prevent catastrophic failures. This technique redistributes stress concentrations and alters crack propagation paths, enhancing structural integrity and preventing crack propagation. This paper explores the concept of using holes as crack arrestors, highlighting their significance in increasing structural resilience and mitigating the risks associated with crack propagation. The crack growth path is estimated by applying the maximum circumferential stress criterion, while the calculation of the associated stress intensity factors is performed by applying the interaction integral technique. To analyze the impact of holes on the crack growth path and evaluate their effectiveness as crack arrestors, additional specimens with identical external dimensions but without any internal holes were tested. This comparison was conducted to provide a basis for assessing the role of holes in altering crack propagation behavior and their potential as effective crack arrestors. The results of this study demonstrated that the presence of a hole had a significant influence on the crack growth behavior. The crack was observed to be attracted towards the hole, leading to a deviation in its trajectory either towards the hole or deflecting around it. Conversely, in the absence of a hole, the crack propagated without any alteration in its path. To validate these findings, the computed crack growth paths and associated stress intensity factors were compared with experimental and numerical data available in the open literature. The remarkable consistency between the computational study results for crack growth path, stress intensity factors, and von Mises stress distribution, and the corresponding experimental and numerical data, is a testament to the accuracy and reliability of the computational simulations. [ABSTRACT FROM AUTHOR]

In a classic paper of 1960, W. H. Cherry and J. I. Gittleman discussed various thermal and electrodynamic aspects of the superconductive transition process relevant to practical applications. In a section of the paper that has remained unnoticed, they proposed a physical model for the Meissner effect. Earlier in 1940–1943, in work that has also remained unnoticed, K. M. Koch had introduced related physical ideas to explain the Meissner effect. Still earlier in 1937, J. C. Slater proposed a model to explain the perfect diamagnetism of superconductors. None of these ideas are part of the conventional London-BCS understanding of superconductivity, yet I will argue that they are essential to understand the Meissner effect, the most fundamental property of superconductors. The unconventional theory of hole superconductivity unifies and extends these ideas. A key missing element in the conventional theory as well as in these early theories is electron-hole asymmetry. A proper understanding of the Meissner effect may help with practical applications of superconductors, as well as to find new superconducting materials with desirable properties. [ABSTRACT FROM AUTHOR]

The excavation of adjacent pits following the initial foundation pit excavation can significantly influence ground settlement. Using a foundation pit excavation project in Changzhou as a prototype, this study employed the numerical simulation method in conjunction with the HSS model to analyze the settlement deformation characteristics of the original excavation and compare them with the recorded monitoring values. In this study, the analysis focused on the ground settlement between two pits by varying the spacing between them at different excavation depths. The findings revealed that the ground settlement does not exhibit a significant increase when the new pit is excavated at a shallow depth. However, it rapidly increases when the excavation depth of the new pit surpasses that of the existing pit. Furthermore, an increase in the distance between the two pits causes the maximum settlement position to shift towards the edge of the new pit. The maximum ground settlement is found to have a linear relationship with both the maximum horizontal displacement of the two pits and the spacing between them. [ABSTRACT FROM AUTHOR]

Photoelectrochemical water splitting is a promising approach to produce green and renewable hydrogen fuel, alleviating the CO2 emissions, air pollution, and energy crisis. However, the efficiency is limited by the recombination of photogenerated carriers and the losses of holes, resulting in a mismatch between the rates of water oxidation and reduction reactions. This article starts with a discussion of the principle of photoelectrochemical water splitting, highlighting the role and importance of holes, and then summarizes the development of the hole transport layer, with a focus on the classification of the hole transport layer, the structure and properties of common hole transport materials, and the construction and improvement of the hole transport layer. Finally, it is concluded with a summary and perspective of strategies for the future development of the hole transport layer. [ABSTRACT FROM AUTHOR]

The steppe marmot (Marmota bobak Mull.) is an important component of the Eurasian forest steppes. However, at the turn of the XIX-XX centuries. The steppe marmot was almost exterminated in Russia. In the Privolzhskaya Forest-Steppe Nature Reserve, as a result of reintroduction, marmots live on the territory of the Ostrovtsovskaya Forest-Steppe. In 2023, in the spring-summer period, using a UAV (DJI MavicAir 2s), we took photographs and interpreted orthophotomaps using the ArcMap 10.4 program. Maps of the location of various types of marmot holes, trails and butanes were created. Vegetation research has been carried out since 2019. At the base of different types of burrows, the floristic composition was identified. On the territory of the Ostrovtsovskaya forest-steppe reserve area, over the past 10 years (since marmots settled this territory), 210 burrows were noted in the surveyed marmot colonies. Three types of burrows have been identified – temporary burrows are divided into protective and permanent summer ones, as well as wintering ones. 78 species of vascular plants were identified in the marmot colonies. The grass species most resistant to failure are Festuca valesiaca, Calamagrostis epigeios and Bromopsis inermis. The total area of territory used by marmots has increased 4 times over 7 years. The degree and nature of the impacts of marmot colonies on vegetation depend on the time and intensity of burrow use, as well as the stability of the plant communities themselves. In the habitats of marmots, herbaceous polycarpics are the absolute dominants; on butanes, the participation of annual and biennials plants.

Copyright of German International Journal of Modern Science / Deutsche Internationale Zeitschrift für Zeitgenössische Wissenschaft is the property of Artmedia24 and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Based on the band structure of TlGaTe compound, the extrema of the valence and conduction bands were determined and the tensor of the components of the inverse effective mass of electrons and holes was calculated. [ABSTRACT FROM AUTHOR]

ABSTRACT The infection cycle of phage λ terminates in lysis mediated by three types of lysis proteins, each disrupting a layer in the bacterial envelope: the S105 holin, the R endolysin, and the Rz/Rz1 spanin complex targeting the inner membrane, cell wall or peptidoglycan, and the outer membrane, respectively. Video microscopy has shown that in most infections, lysis occurs as a sudden, explosive event at a cell pole, such that the initial product is a less refractile ghost that retains rod-shaped morphology. Here, we investigate the molecular basis of polar lysis using time-lapse fluorescence microscopy. The results indicate that the holin determines the morphology of lysis by suddenly forming two-dimensional rafts at the poles about 100 s prior to lysis. Given the physiological and biochemical similarities between the lambda holin and other class I holins, dynamic redistribution and sudden concentration may be common features of holins, probably reflecting the fitness advantage of all-or-nothing lysis regulation.IMPORTANCEIn this study, we use fluorescent video microscopy to track -green fluorescent protein (GFP)-labeled holin in the minutes prior to phage lysis. Our work contextualizes prior genetic and biochemical data, showing when hole formation starts and where holin oligomers form in relation to the site of lytic rupture. Furthermore, prior work showed that the morphology of lambda-infected cells is characterized by an explosive event starting at the cell pole; however, the basis for this was not clear. This study shows that holin most often oligomerizes at cell poles and that the site of the oligomerization is spatially correlated with the site of lytic blowout. Therefore, the holin is the key contributor to polar lysis morphology for phage lambda.

Perforations after endoscopic retrograde colangiopancreatography (ERCP) are divided into four types. Type 1 refers to the duodenum, type 2 the periampullary region, type 3 the bile duct itself, and type 4 the observation of retroperitoneal free air on cross-sectional imaging. The treatment of type 2 biliary perforations remains debatable. We present a patient who was successfully treated with a self-expandable metal stent (SEMS) without the need for surgery or any complications. [ABSTRACT FROM AUTHOR]

We report on comprehensive experimental studies of turbulence spreading in edge plasmas. These studies demonstrate the relation of turbulence spreading and entrainment to intermittent convective density fluctuation events or bursts (i.e. blobs and holes). The non-diffusive character of turbulence spreading is thus elucidated. The turbulence spreading velocity (or mean jet velocity) manifests a linear correlation with the skewness of density fluctuations, and increases with the auto-correlation time of density fluctuations. Turbulence spreading by positive density fluctuations is outward, while spreading by negative density fluctuations is inward. The degree of symmetry breaking between outward propagating blobs and inward propagating holes increases with the amplitude of density fluctuations. Thus, blob-hole asymmetry emerges as crucial to turbulence spreading. These results highlight the important role of intermittent convective events in conveying the spreading of turbulence, and constitute a fundamental challenge to existing diffusive models of spreading.

The article deals with the issues of improving the productivity and quality of drilling holes. The results of systematization and introduced into production methods of drilling with changing cutting modes during insertion and entry of the drill, grinding of descending chips and removal of it and the cutting zone are developed, tool materials, coolant compositions are promising, cutting modes are optimal, a mathematical model of the influence of modes and methods of drilling on hole accuracy and quality. An algorithm of the proposed drilling methods for machine tools with program control has been compiled.

In a classic paper of 1960, W. H. Cherry and J. I. Gittleman discussed various thermal and electrodynamic aspects of the superconductive transition process relevant to practical applications. In a section of the paper that has remained unnoticed, they proposed a physical model for the Meissner effect. Earlier in 1940–1943, in work that has also remained unnoticed, K. M. Koch had introduced related physical ideas to explain the Meissner effect. Still earlier in 1937, J. C. Slater proposed a model to explain the perfect diamagnetism of superconductors. None of these ideas are part of the conventional London-BCS understanding of superconductivity, yet I will argue that they are essential to understand the Meissner effect, the most fundamental property of superconductors. The unconventional theory of hole superconductivity unifies and extends these ideas. A key missing element in the conventional theory as well as in these early theories is electron-hole asymmetry. A proper understanding of the Meissner effect may help with practical applications of superconductors, as well as to find new superconducting materials with desirable properties.

The primary focus of this paper is to investigate the application of ANSYS Workbench 19.2 software’s advanced feature, known as Separating Morphing and Adaptive Remeshing Technology (SMART), in simulating the growth of cracks within structures that incorporate holes. Holes are strategically utilized as crack arrestors in engineering structures to prevent catastrophic failures. This technique redistributes stress concentrations and alters crack propagation paths, enhancing structural integrity and preventing crack propagation. This paper explores the concept of using holes as crack arrestors, highlighting their significance in increasing structural resilience and mitigating the risks associated with crack propagation. The crack growth path is estimated by applying the maximum circumferential stress criterion, while the calculation of the associated stress intensity factors is performed by applying the interaction integral technique. To analyze the impact of holes on the crack growth path and evaluate their effectiveness as crack arrestors, additional specimens with identical external dimensions but without any internal holes were tested. This comparison was conducted to provide a basis for assessing the role of holes in altering crack propagation behavior and their potential as effective crack arrestors. The results of this study demonstrated that the presence of a hole had a significant influence on the crack growth behavior. The crack was observed to be attracted towards the hole, leading to a deviation in its trajectory either towards the hole or deflecting around it. Conversely, in the absence of a hole, the crack propagated without any alteration in its path. To validate these findings, the computed crack growth paths and associated stress intensity factors were compared with experimental and numerical data available in the open literature. The remarkable consistency between the computational study results for crack growth path, stress intensity factors, and von Mises stress distribution, and the corresponding experimental and numerical data, is a testament to the accuracy and reliability of the computational simulations.

• Investigated the effects of loading rates and inclusion type on the dynamic performance. • Revealed the progressive failure process and failure modes of filled sandstone under impact loads. • Discussed the relationships between energy evolution and dynamic mechanical response. Inclusions are often present in rock defects, which can compensate for some of the problems of low rock strength and poor stability caused by hole defects. Specimens containing inclusions exhibit different mechanical properties under dynamic loading, and the strength change, energy evolution law and fracture mechanism deserve to be clearly discussed. In this work, a dynamic impact test of sandstone with circular inclusions was carried out. The failure process of each sample was recorded by a high-speed camera, and the influences of the inclusion strength and strain rate on the dynamic impact performance of the sandstone were analysed. Increasing the strain rate and inclusion strength can significantly improve the dynamic compressive strength of a sample. The dissipated energy density and impact toughness index are positively correlated with the strain rate. The dissipated energy density increased the most when the sample type was FA, at 10.6%. When the sample type was FD, the impact toughness index increased the most, which was 49.1%. In the early stage of loading, the localized strain is mainly concentrated inside the filler and gradually evolves into deformation of the filler and extension of shear cracks in the late stage of loading. The failure modes of a sample are not the result of a single factor but are influenced by both the strain rate and the filler. The types of cracks in the samples are mainly shear cracks and shear–tension composite cracks. [ABSTRACT FROM AUTHOR]

Circular holes with a mean bias flow passing through them can amplify or damp acoustic energy and this property is relevant for many industrial applications. In this work, we propose a methodology to design the edges of such holes so that the acoustic damping is maximised. The approach relies on a Bayesian optimisation framework and is illustrated in a short circular hole with a mean laminar bias flow. The acoustic response of the perforation is characterised numerically using a two-step approach where, first, a steady mean flow is computed as the solution of the incompressible Navier–Stokes equations. Second, small-amplitude acoustic perturbations are superimposed on this mean flow and their dynamics are obtained as the solution of the linearised compressible Navier–Stokes equations. Both the upstream and downstream edges of the hole are modified with 45°chamfers. The sizes of these two chamfers are the control parameters optimised to maximise the acoustic absorption coefficient. The results of this letter show that the careful design of the edges can dramatically increase the acoustic energy that holes can damp: the hole investigated here goes from one generating 55% more acoustic energy than incident upon it at a given frequency to one that damps 46% of this acoustic energy. • The acoustic damping of short holes can be dramatically increased by optimising their edges. • We present an optimisation method to maximise the acoustic damping of holes with bias flow. • The method can be readily combined with any numerical or experimental techniques. [ABSTRACT FROM AUTHOR]

• Nine full-scale tests conducted on interior slab-column connections with openings and unbalanced moments. • Discussion on the impact of number and location of openings. • Discussion on the impact of unbalanced moment orientation concerning the opening's location. • Overview of design approaches that clarify the specifications of slab-column connections with openings. The impact of openings and moment transfer on punching shear resistance was investigated by conducting tests on nine interior slab-column connections measuring 2,400 mm square and 150 mm thick. The connections were subjected to different unbalanced moment orientations with eccentricities of 250 mm and 500 mm, and without shear reinforcement. The openings, located on the faces of the rectangular supports, had widths of either 200 mm × 200 mm or 200 mm × 300 mm. The study analysed ultimate loads, vertical displacements, flexural reinforcement strains, and concrete strains. The experimental punching strength was compared to theoretical predictions according to ACI 318:19, fib MC 2010:13, for different levels of approximation and the 2nd generation of Eurocode 2 prEN 1992-1-1:21. Observations are provided regarding the code's calculation for slabs with openings. [ABSTRACT FROM AUTHOR]

While Light Detection and Ranging (LiDAR)-based sensors exhibit considerable potential for transportation infrastructure management, not all infrastructure elements can be comprehensively captured by point clouds, leading to the formation of undesirable "holes" due to both temporary and permanent occlusions. It is imperative to devise mechanisms for identifying and predicting the missing data within these "holes" to ensure the continuous acquisition of critical inventory information. This paper describes a method for generating point clouds based on Bézier curves, which effectively fills the voids within the infrastructure. This method comprises three integral processes, including angle-based boundary detection, identification of principal elevation change, and Bézier curve-based hole filling. The method demonstrates promising results on different roadside surfaces and at different ranges of scales of "holes". Case studies on the sidewalk, and sound barrier inventories show that the proposed method can significantly improve the quality of the point cloud data for subsequent measurements. • Develops an automated Bézier curve-based data generation methodology for LiDAR point cloud data from common transportation scenes. • Develops boundary detection and principal elevation change identification methods for synthesizing missing data's characteristics. • Develops comprehensive validation and case studies to quantitatively demonstrate the performance of the developed method. • Advances the understanding of LiDAR point cloud data and maximizes its utilization in critical transportation asset management applications. [ABSTRACT FROM AUTHOR]

The infection cycle of phage λ terminates in lysis mediated by three types of lysis proteins, each disrupting a layer in the bacterial envelope: the S105 holin, the R endolysin, and the Rz/Rz1 spanin complex targeting the inner membrane, cell wall or peptidoglycan, and the outer membrane, respectively. Video microscopy has shown that in most infections, lysis occurs as a sudden, explosive event at a cell pole, such that the initial product is a less refractile ghost that retains rod-shaped morphology. Here, we investigate the molecular basis of polar lysis using time-lapse fluorescence microscopy. The results indicate that the holin determines the morphology of lysis by suddenly forming two-dimensional rafts at the poles about 100 s prior to lysis. Given the physiological and biochemical similarities between the lambda holin and other class I holins, dynamic redistribution and sudden concentration may be common features of holins, probably reflecting the fitness advantage of all-or-nothing lysis regulation.IMPORTANCEIn this study, we use fluorescent video microscopy to track -green fluorescent protein (GFP)-labeled holin in the minutes prior to phage lysis. Our work contextualizes prior genetic and biochemical data, showing when hole formation starts and where holin oligomers form in relation to the site of lytic rupture. Furthermore, prior work showed that the morphology of lambda-infected cells is characterized by an explosive event starting at the cell pole; however, the basis for this was not clear. This study shows that holin most often oligomerizes at cell poles and that the site of the oligomerization is spatially correlated with the site of lytic blowout. Therefore, the holin is the key contributor to polar lysis morphology for phage lambda., Competing Interests: The authors declare no conflict of interest.