Location Of Holes Research Articles

A three-dimensionally printed template for locating the screw channel in a cement-retained implant-supported crown: A digital workflow

Locating the screw channel in a cement-retained implant-supported crown is challenging. This article describes a fully digital workflow for fabricating a 3D printed template which can accurately guide the dentist to find the screw channel. A definitive implant cast from the patient and an implant planning software program are used in the workflow. This technique provides precise guidance for finding the location and angulation of the abutment screw access hole.

Linear regression and artificial neural network models for predicting abrasive water jet marble drilling quality

Marble is a fragile and heterogeneous material whose properties vary depending on the nature and origin of the marble. Therefore, the marble machining process requires the skills and know-how of the stone cutter to manually configure the machining parameters for each piece of marble. This study addresses the enhancement of quality achieved by marble drilling processes in the industry. The objective of this work is to drill marble with high quality performance and avoid fracturing the material. This article focuses on the process of drilling white Carrara marble with an abrasive water jet. This unconventional tool significantly reduces unwanted damage resulting from the drilling process (fractures, spalling) compared to the conventional drilling process (rotating abrasive tools). The effect of waterjet cutting parameters, namely jet pressure, stand-off distance, nozzle traverse speed, abrasive flow rate, and hole diameter on drilling tolerances is studied. Five defects in the drilling process are modeled in this work: surface roughness, hole circularity, hole cylindricity, hole location error, and hole taper, using analysis of variance of linear regression models and an artificial neural network width high accuracy. These models could be of great interest to stone cutters to configure marble machining parameters and improve marble manufacturing quality.

Controversies in the Surgical Treatment of Chronic Subdural Hematoma: A Systematic Scoping Review.

Chronic subdural hematoma (cSDH) is one of the most common neurosurgical entities, especially in the elderly population. Diagnosis is usually established via a head computed tomography, while an increasing number of studies are investigating biomarkers to predict the natural history of cSDH, including progression and recurrence. Surgical evacuation remains the mainstay of treatment in the overwhelming majority of cases. Nevertheless, many controversies are associated with the nuances of surgical treatment. We performed a systematic review of the literature between 2010 and 2022, aiming to identify and address the issues in cSDH surgical management where consensus is lacking. The results show ambiguous data in regard to indication, the timing and type of surgery, the duration of drainage, concomitant membranectomy and the need for embolization of the middle meningeal artery. Other aspects of surgical treatment—such as the use of drainage and its location and number of burr holes—seem to have been adequately clarified: the drainage of hematoma is strongly recommended and the outcome is considered as independent of drainage location or the number of burr holes.

Microencapsulated PCM in the cement brick cavity: analysis of melting and solidification behaviour

ABSTRACT The use of latent heat storage systems using phase change materials is becoming increasingly popular for passive building cooling applications. This paper introduces a novel cement brick design in which a microencapsulated PCM MEP29 is directly filled into the brick holes near the outer wall. The melting and solidification pattern of the PCM in the brick cavity is analysed numerically by shifting the location of the PCM holes from the outer to inner wall sides by 30, 40, 50, and 75 mm, respectively. Melting and solidification are both delayed when the PCM position is moved towards the centre of the brick. The melting time for mPCM 75 is 57 min longer than for mPCM 30 brick, with a 25-minute delay in the start of solidification. Furthermore, the unique brick design with offset PCM holes reduces the chance of heat reentry into the living space during solidification.

DNA metabarcoding reveals impact of local recruitment, dispersal, and hydroperiod on assembly of a zooplankton metacommunity.

Understanding the environmental impact on the assembly of local communities in relation to their spatial and temporal connectivity is still a challenge in metacommunity ecology. This study aims to unravel underlying metacommunity processes and environmental factors that result in observed zooplankton communities. Unlike most metacommunity studies, we jointly examine active and dormant zooplankton communities using a DNA metabarcoding approach to overcome limitations of morphological species identification. We applied two-fragment (COI and 18S) metabarcoding to monitor communities of 24 kettle holes over a two-year period to unravel (i) spatial and temporal connectivity of the communities, (ii) environmental factors influencing local communities, and (iii) dominant underlying metacommunity processes in this system. We found a strong separation of zooplankton communities from kettle holes of different hydroperiods (degree of permanency) throughout the season, while the community composition within single kettle holes did not differ between years. Species richness was primarily dependent on pH and permanency, while species diversity (Shannon Index) was influenced by kettle hole location. Community composition was impacted by kettle hole size and surrounding field crops. Environmental processes dominated temporal and spatial processes. Sediment communities showed a different composition compared to water samples but did not differ between ephemeral and permanent kettle holes. Our results suggest that communities are mainly structured by environmental filtering based on pH, kettle hole size, surrounding field crops, and permanency. Environmental filtering based on specific conditions in individual kettle holes seems to be the dominant process in community assembly in the studied zooplankton metacommunity.

Hydrodynamic characteristics and wake evolution of a submarine pipe with the presence of gas leakage at a low Reynolds number of 160

Hydrodynamic characteristics and wake structures of a submarine gas transmission pipe with the presence of gas leakage are of significance from a scientific and practical viewpoint. In this paper, we present a numerical investigation of flow past a leaking pipe at a low Reynolds number of 160 using the Eulerian–Eulerian multi-fluid volume of fluid model. The focus is on the effects of gas buoyancy and the location of the leak hole on the wake flow structures, bubble–vortex interference, and hydrodynamic forces. The variation of drag and lift coefficients is highly associated with the evolution of gas bubbles and the interaction between the bubble-induced vortices and the shear layers. When the gas buoyancy is ignored, the alterations of the main vortex structure and hydrodynamic forces are not sensitive to the location of the leak hole. The bubble-induced vortices are encompassed by the two shear layers and quickly dissolved in the main vortices. Finally, the released gas bubbles are locked in the center of main vortices and convected downstream with them. In contrast, when the buoyancy is considered, the gas bubbles line up in the upper shear layer, strongly interfering with the formation of the upper main vortex. Each gas bubble introduces a pair of small vortices that experience complicated merging or splitting during the migration. Consequently, the upper main vortex is suppressed at θ = 90° and vanished at θ = 180° and θ = 270° (θ is measured clockwise from the forward stagnation point), leading to the negative time-averaged lift force and the same-frequency oscillation of drag and lift coefficients. Due to the upward migration of gas bubbles from both front and rear surfaces at θ = 270°, the evolution of bubble-induced vortices is more complicated and the oscillation of hydrodynamic forces is significantly enhanced in comparison with other cases.

Optimal Reconfiguration of Electrical Distribution System Using Heuristic Methods with Geopositioning Constraints

Natural disasters have great destructive power and can potentially wipe out great lengths of power lines. A resilient grid can recover from adverse conditions and restore service quickly. Therefore, the present work proposes a novel methodology to reconfigure power grids through graph theory after an extreme event. The least-cost solution through a minimum spanning tree (MST) with a radial topology that connects all grid users is identified. To this end, the authors have developed an iterative minimum-path heuristic algorithm. The optimal location of transformers and maintenance holes in the grid is obtained with the modified Prim algorithm, and the Greedy algorithm complements the process. The span distance and capacity restrictions define the transformer’s number, where larger spans and capacities reduce the number of components in the grid. The performance of the procedure has been tested in the urban zone Quito Tenis of Ecuador, and the algorithm proved to be scalable. Grid reconfiguration is pushed through a powerful tool to model distribution systems such as CYMDIST, where the voltage drops were minor than 3.5%.

Fracture Resistance of Screw-Access Holes in Zirconia Full-Arch Implants.

To present a sample preparation and test methodology for evaluating the fracture resistance of ceramic materials configured in a way similar to the screw-access holes found in implant-supported ceramic full-arch devices. A finite-width rectangular plate with a central hole was designed to evaluate the critical stresses of ceramic full-arch screw-access holes. Different load scenarios were investigated by comparing forces applied to BruxZir Esthetic (Glidewell Laboratories) and BruxZir Esthetic enhanced with BruxZir Steel (Glidewell Laboratories) specimens. Using the proposed test method, it was found that the fracture resistance of full-arch prostheses is largely dependent on the location of the screw-access hole and the inherent mechanical properties of the material (P < .001). The finite-width plate model may be suitable for evaluating the fracture resistance of ceramic full-arch prostheses. The fracture resistance of 3D ceramic full-arch prostheses can be greatly improved by improving the mechanical properties of the material and/or increasing the wall thickness of the screw access hole by relocation.

Effect of web perforations on end-two-flange web crippling behaviour of roll-formed aluminium alloy unlipped channels through experimental test, numerical simulation and deep learning

Aluminium alloy has recently become popular in New Zealand’s construction sector as a sustainable building material. However, in roll-formed aluminium alloy (RFA) channel beams, particularly those having web holes, cripples at points of concentrated or localised loading. In this paper, end-two-flange (ETF) web crippling behaviour of RFA unlipped channels having web holes was investigated using experimental tests, numerical simulations and a deep learning model referred as deep belief network (DBN). A total of 1080 data points was generated to train the DBN, using a finite element (FE) model that was validated using 30 new experimental results reported in this paper. Compared to the test data, the DBN predictions were conservative by around 6%. Using the DBN predictions, a comprehensive parametric study was undertaken which used the validated FE model in order to explore the effects of hole size, hole location, section thickness, and bearing plate on the web crippling strength of RFA channels having web holes. Web crippling strengths obtained from the DBN, tests and finite element analysis (FEA) were utilised to evaluate the performance of current design specifications from the American Iron and Steel Institute (AISI), Australian/New Zealand Standards (AS/NZS 1664; AS/NZS 4600:2018) and Eurocode (CEN 2006, 2007). It is shown that the current design rules are not reliable to predict the web crippling strength of RFA unlipped channels with web holes. As a consequence of the parametric analysis, new web crippling strength and web crippling strength reduction factor formulae for perforated RFA unlipped channels were proposed. A reliability analysis was then conducted, which confirmed that the proposed equations are capable of predicting the ETF web crippling strength of perforated RFA unlipped channels.

Design and Implementation of W-shaped Steel Band Hole Image Recognition System Based on OpenCV-Python

The mine Roofbolter is widely used in drilling and supporting of underground roof and side wall, which greatly alleviates the imbalance of driving anchor. However, with the progress of sensor technology, electrical and electronic technology, electro-hydraulic proportional control technology and the continuous improvement of users’ requirements for the safety and efficiency of bolt support, domestic and foreign mining equipment manufacturers have carried out the development of automatic bolt and anchor cable support equipment, especially to improve the performance requirements of control system and develop intelligent visualization technology. At present, the hole location in the process of drilling still needs to be identified and located by human eyes, which is inefficient and the working environment is a great threat to the physical and mental health of personnel, so it is urgent to introduce computer technology and artificial intelligence technology. In this paper, with the help of image recognition technology, machine vision recognition replaces human eye recognition of hole location, and puts forward an image recognition technology of W-shaped steel belt hole recognition system based on OpenCV to assist the scheme, so as to ensure the safety and efficiency of roadway support. This system uses pychar, opencv and python language to realize the recognition and positioning of W-shaped steel strip hole. The scheme has the advantages of small amount of calculation, high accuracy and fast recognition speed. This research conclusion provides a reference for the further spatial positioning analysis of W-shaped steel belt hole, and improves the efficiency of underground support operation and personnel safety.

Constraining Global Coronal Models with Multiple Independent Observables

Global coronal models seek to produce an accurate physical representation of the Sun’s atmosphere that can be used, for example, to drive space-weather models. Assessing their accuracy is a complex task, and there are multiple observational pathways to provide constraints and tune model parameters. Here, we combine several such independent constraints, defining a model-agnostic framework for standardized comparison. We require models to predict the distribution of coronal holes at the photosphere, and neutral line topology at the model’s outer boundary. We compare these predictions to extreme-ultraviolet (EUV) observations of coronal hole locations, white-light Carrington maps of the streamer belt, and the magnetic sector structure measured in situ by Parker Solar Probe and 1 au spacecraft. We study these metrics for potential field source surface (PFSS) models as a function of source surface height and magnetogram choice, as well as comparing to the more physical Wang–Sheeley–Arge (WSA) and the Magnetohydrodynamic Algorithm outside a Sphere (MAS) models. We find that simultaneous optimization of PFSS models to all three metrics is not currently possible, implying a trade-off between the quality of representation of coronal holes and streamer belt topology. WSA and MAS results show the additional physics that they include address this by flattening the streamer belt while maintaining coronal hole sizes, with MAS also improving coronal hole representation relative to WSA. We conclude that this framework is highly useful for inter- and intra-model comparisons. Integral to the framework is the standardization of observables required of each model, evaluating different model aspects.

Wrinkling suppression in thin membranes using designed geometrical features

The rapidly increasing use of thin membranes; especially in the fabrication of flexible electronics, has motivated investigating the wrinkling behavior of these membranes. Wrinkling has an undesirable effect since wrinkles degrade the surface accuracy of structures incorporating thin membranes. This work introduces and evaluates an approach based on including optimized geometric features in thin membranes to suppress their wrinkling behavior. The ability of the optimized geometric features to suppress wrinkling in a 25 μm thick polyimide membrane subjected to uniaxial stretching is investigated computationally and experimentally in this work. A finite element model is developed to predict the wrinkling behavior of the membrane. An experimental setup equipped with 3D digital image correlation system is used to determine the wrinkles pattern, amplitude, and wavelength. Symmetric circular holes are introduced in the membrane to redistribute the stress field, eliminate the fluctuation in the minor principal stress in the membrane, and suppress wrinkles. The location and size of the circular holes are determined by coupling the Non-Linear Programming by Quadratic Largrangian technique and finite element simulations. An optimal design is obtained and the experimental results show that the optimally designed holes effectively suppressed the wrinkling behavior.

Scientific Results of the Hydrate-01 Stratigraphic Test Well Program, Western Prudhoe Bay Unit, Alaska North Slope

The United States Department of Energy, the MH21-S Research Consortium of Japan, and the United States Geological Survey are collaborating to enable gas hydrate scientific drilling and extended-duration reservoir response testing on the Alaska North Slope. To feasibly execute such a test, a location is required that is accessible from existing roads and gravel pads and that can be occupied without disrupting ongoing industry operations. A review of potential locations meeting these criteria determined the likely occurrence of gas hydrate in two fine-grained marginal-marine sands of Tertiary age in the vicinity of the inactive “Kuparuk State 7-11-12” exploration pad in the western Prudhoe Bay Unit (PBU). Existing well and seismic data for that site were insufficient to preclude the potential for free gas occurrence within the deeper (and most prospective) target sand. Therefore, with support from the PBU Working Interest Owners, Alaska Department of Natural Resources, and Petrotechnical Resources Alaska, the Hydrate-01 Stratigraphic Test Well (STW) was drilled in December 2018 to confirm the suitability of the site for future gas hydrate scientific testing. The Hydrate-01 well was successfully drilled to −3290 ft (1003 m) subsea vertical depth at a bottom hole location of approximately 900 ft (∼275 m) east of the surface location. The drilling program featured acquisition of a full suite of logging while drilling data, the collection of side-wall pressure cores, and the installation of distributed temperature and distributed acoustic sensor fiber-optic cables. The log data acquired confirmed the occurrence of gas hydrate at high saturation in two target sands. Integrated evaluation of log and sidewall core data provide petrophysical and geomechanical property information that allow for potential reservoir response to depressurization to be simulated. The deeper “B1 sand” is deemed to be most favorable for reservoir response testing as a result of confirmed gas hydrate occurrence in sediments of high intrinsic permeability, location within 100 ft (30 m) of the base of gas hydrate stability, and minimal risk for direct communication with permeable water-bearing (hydrate-free) zones. The shallower “D1 sand” provides a secondary target that is differentiated by colder in situ temperatures and the interpreted direct hydraulic communication to a lower section of non-hydrate-bearing, water-saturated sand. The Hydrate-01 log data also confirm the occurrence of at least one sub-seismic fault in close proximity to the B1 sand reservoir. To better image the distribution of the gas-hydrate-bearing reservoir sections and associated faults, a three-dimensional (3D) vertical seismic profile was conducted in early 2019 using the distributed acoustic sensors installed as part of the Hydrate-01 STW completion. Detailed two-dimensional (2D) and 3D geologic models have been constructed to enable numerical simulations to inform the planning for potential future scientific tests of reservoir response to depressurization at the site.

The interaction between the latticework duct and film cooling on the thermal performance with different film cooling hole locations

This paper numerically explored the influence of the film cooling hole locations and blowing ratios on the thermal performance both in the latticework duct and film cooling. The Realizablek−ε turbulence model and polyhedral mesh were utilized to conduct this study. The film cooling hole was successively installed from the jet region to turning region for different cases. The blowing ratio included 0.2, 0.8, 1.0 and 1.25. These results suggested that the different film hole locations could induce the different flow and cooling performance both in the latticework duct and film cooling channel. The film cooling hole destroyed the boundary layer and was conducive to heat exchange enhancement in the latticework duct. The film cooling hole configured near the turning region had more remarkably effect on the thermal performance. The different location means the different inlet condition for the film cooling. Maximum value of film cooling effectiveness was reached as the film cooling hole installed near the jet region because of the small counter-rotating vortex.

Effects of pulsed endwall air injection on corner separation and vortical flow of a compressor cascade

ABSTRACT Air injection is an effective method to eliminate flow separation and improve blade loading in compressors. In existing studies on unsteady air injection, achieving a better control effect than steady injection with lower injection consumption is a major difficulty and challenge. In this work, pulsed endwall air injection (PEAI) was carried out numerically in a highly loaded compressor cascade under different injection frequencies and injection amplitudes. The mechanism through which PEAI influences corner separation and vortical flow, especially the effect of initial injection phase on the flow field of compressor cascade, was revealed. The results showed that PEAI effectively suppressed the corner separation with lower injection mass flow rate compared with steady endwall air injection (SEAI). The time-averaged overall loss coefficient and endwall loss coefficient were reduced by 10.5% and 28.7%, respectively, under the optimal PEAI scheme. Higher injection amplitude exhibited a more effectively controlled range in the suction corner, which led to a decrease in corner separation and deterioration of the mid-span flow field. The interaction between trailing edge separation and low-momentum fluid at mid-span led to the formation of an injection vortex. When conducting PEAI, the effect of inertia was observed for flow in the injection hole, which was derived from the interactions between injection fluid at different velocities and will increase with the improvement of injection frequency. The effects of injection location and diameter of the injection hole were also investigated. The injection location of PEAI affected the flow field by changing the effect region of the injection and low-momentum fluid near the endwall. The injection hole diameter had a significant impact on the intensity of the passage vortex and mid-span flow field.

Accuracy Evaluation of Thermoelastic Stress Analysis with the Use of Experimental and Numerical Methods.

Thermoelastic Stress Analysis (TSA) is one of the very few methods allowing the determination of a continuous stress distribution on the object’s surface under variable loading conditions. Such results provide a lot of valuable information in the field of technical condition assessment and residual life prediction. In order to improve the accuracy of the TSA, the Lock-In signal processing method is implemented. This research is aimed at verifying the effectiveness of this improvement and determining the TSA stress detection threshold, as it is important information in terms of the applicability of this method in the low-stress conditions encountered in considerations of fatigue of load-carrying structures. A steel sample with a centrally located hole was subjected to cyclic loads to determine the threshold of stress detection and accuracy of TSA. As a result of the research, the relationship between the magnitude of stress excitations and the underestimation of the measured stresses was developed. Based on the conducted investigations, it was concluded that reasonable TSA results can be acquired for excitations that induce a temperature response above 10 mK (0.5 NEDT). The presented field test example proves that in industrial applications reasonable results can be acquired for thermal responses below the NEDT of the IR camera. It was concluded that it is possible to successfully implement TSA in low-stress applications (temperature response below NEDT).

An experimental and numerical investigation of film cooling effectiveness on a gas turbine blade tip region

In this paper, the effects of coolant flow rate, location of film holes, tip clearance height, and density ratio on blade tip film cooling effectiveness were experimentally investigated using pressure-sensitive paint. And numerical simulation was used to analyze the flow characteristic. Three different turbine blade tips were studied under a mainstream Reynolds number of 6.7 × 105. The pressure ratio was 1.7 and the blowing ratio ranged from 0.4 to 2.2. The results indicated that the cooling effectiveness gradually increased as the blowing ratio increased. The film tends to lift off under a larger blowing ratio, resulting in a decrease in the cooling effectiveness. The squealer tip with an inclined pressure side rim exhibited better film cooling effectiveness under the design conditions. The film cooling effectiveness on the pressure-side rim was lower than that on the suction-side rim under the same operating conditions. The analyses also indicated that an increase in the density ratio effectively enhances film cooling. Compared with the most published investigations conducted in a low-speed wind tunnel, these studies can be better applied to turbine blade cooling design.

EVO+ Implantable Collamer Lens KS-aquaPORT Location, Stability, and Impact on Quality of Vision and Life.

To determine the longitudinal variation in the KS-aquaPORT central hole location of the phakic EVO+I Implantable Collamer Lens (ICL) (STAAR Surgical) and analyze its influence on visual performance, quality of vision (QoV), and quality of life (QoL). A prospective study was performed including 36 patients who had EVO+ ICL implantation. The KS-aquaPORT central hole location (Cartesian and polar coordinates) was determined with respect to the pupil center and visual axis. The effect of time (6-month follow-up) on central hole location was analyzed using linear mixed models. The effect of the KS-aquaPORT location on visual performance, QoV, and QoL parameters was assessed with multivariate regression models. With respect to the visual axis, no significant changes in KS-aquaPORT location were found during follow-up. With respect to the pupil center, the X-coordinate and radius of KS-aquaPORT location showed modest, but significant (P ≤ .05) differences between 1-week and 3-month postoperative visits, and between 1-week and 6-month visits. X-coordinate variation was significant (P = .022) between 1-and 6-month visits. With respect to the visual axis, greater KS-aquaPORT decentration was associated with worse visual acuity (X-coordinate: P = .004; radius: P = .006), and inferior decentration with longer xenon-type glare photostress recovery time (P = .021). With respect to the pupil center, a lower radius was associated with better QoV scores (P ≤ .01) and temporal decentration produced higher ring-shaped dysphotopsia (P = .007). EVO+ ICL KS-aquaPORT location appears to be clinically stable up to 6 months postoperatively. A central location of the EVO+ ICL KS-aquaPORT hole is preferred because it allows reduced perception of dysphotopic phenomena that can result in better QoV. [J Refract Surg. 2022;38(3):177-183.].

A Case Study on Usage of Actual Soil Condition below Multi-Storied Building under Seismic Loading at Indore City

Abstract: The people try to live in high rise structures due to increase in the demands of high rise structure with architectural impact. Soil profile beneath the structure also plays an important role to make the superstructure along with the sub-structure on its location. A Structure is said to acceptable if it satisfies the design criteria and hold itself in the same location to oppose the lateral forces. To show the importance of the soil below the construction area, soil investigations were carried out at Indore city. Total 11 bore hole database has used in this research. We have analyzed about different bore holes location for efficient building construction and effectiveness of residential apartment. After observing the necessary needs and fixing the objectives, we have created 11 (G+6) models and different cases named as CaseL1 to Case L11. The input parameters of soil profile used in this research is based on a part of Indore city area. After analysis of output parameters, the main points have been noted down the project concluded that efficient location for construction will be Case L with least result parameters under seismic loads. Keywords: Transverse Direction, Soil Profile, Residential Apartment, Soil Investigation

Modeling of nicotine and harmful gas yields in carbon-heated tobacco products: Effect of hole arrangement

Carbon-heated tobacco products (CHTPs) recently emerged as a type of safer nicotine product. To prevent the discharge of harmful substances, the heating and pyrolysis of tobacco should be precisely controlled. Herein, we investigate the heat transfer mechanism and pyrolysis characteristics of tobacco using computational fluid dynamics (CFD) modeling of a CHTP. In addition, we analyze the yields of volatile species, the thermal stability of the CHTP during pyrolysis, and the optimal combination of holes. We also fabricated a prototype heat source and used the temperature distribution thereof in the CFD modeling. Using one particular hole location, puffing exhibited a significant effect on the temperature distribution of the tobacco plug and the yields of volatile species. Furthermore, in terms of nicotine yield distribution, the air flow rate through this hole was a significant factor. However, an extremely high air flow rate increased the yields of harmful substances by leveling the temperature of the tobacco plug. In the cases investigated, the maximum overall nicotine yield was 81.1%, while nicotine, tar, CO, and other gases were obtained in respective yields of 76%, 75%, 26%, and 63% under the condition minimizing the ratio between the combined yield of harmful substances and the yield of nicotine. To the best of our knowledge, this is the first published CFD study regarding CHTPs and yields valuable insight into their manufacturing parameters.