Location Of Holes Research Articles

Multi-Objective Optimisation of an Aerostatic Pad: Design of Position, Number and Diameter of the Supply Holes

ABSTRACTIn this paper, a rectangular aerostatic bearing with multiple supply holes is optimised with a multiobjective optimisation approach. The design variables taken into account are the supply holes position, their number and diameter, the supply pressure, while the objective functions are the load capacity, the air consumption and the stiffness and damping coefficients. A genetic algorithm is applied in order to find the Pareto set of solutions. The novelty with respect to other optimisations which can be found in literature is that number and location of the supply holes is completely free and not associated to a pre-defined scheme. A vector x associated with the supply holes location is introduced in the design parameters and given in input to the optimizer.

Reduction of Ripple Toothed Torque in the Internal Permanent Magnet Electric Motor by Creating Optimal Combination of Holes in the Rotor Surface Considering Harmonic Effects

Due to the widespread use of electric motors in various industries, it is very important to have optimally designed motors in that they have high efficiency and lower negative effects on the quality of the power grid. Therefore, in this paper, the effects of winding type (wide and concentrated) on ripple torque in internal permanent magnet motor (IPMM) are investigated. In order to reduce the ripple torque and to increase the average torque, by making optimal holes in the rotor surface and using the sensitivity analysis method, the structure of the IPMM is improved. In this method, the number, dimensions and location of holes are optimized using the sensitivity analysis approach, which reduces the ripple torque of the motor. Using a concentrated winding instead of a wide winding, the toothed ripple torque is reduced by approximately 75% while maintaining the average torque value. Also, by making holes in the rotor surface and optimizing them using the finite element technique and sensitivity analysis, it is demonstrated that the amount of ripple torque by 20%. In the proposed approach, it is proved that in the concentrated winding, in addition to reducing the spatial harmonics, the average amount of torque can also be improved. Obtained results of the simulation confirm the effectiveness of the proposed method.

Numerical Simulation of Hole Distribution Blasting with Different Distribution Forms

According to the vibration of cut blasting, the number of holes and the location of holes are reasonably designed by using finite element software LS-DYNA. The rectangular holes and hollow holes in straight cut are simulated respectively. Of the hole in the straight-cut undercut blasting vibration law. The analysis shows that the larger the diameter of the hole is, the better the vibration reduction is. The more the number of holes is, the more obvious the damping effect is. The best blasting effect of the large diameter hollow hole and the large diameter rectangular hole is 0.93cm/s Reduce the blasting vibration speed, buffered the blasting time; get both a good blasting effect and effective rapid damping effect.

Compression Behavior of CFST Stub Columns with Holes

Holes are always opened in the steel tubes during the inspection and revision of initial concrete imperfections in concrete filled steel tubular (CFST) columns. The structural performance of such composite columns with holes may have obvious differences in comparison with normal CFST members. This paper intends to investigate the influences of sectional type, holes location, holes size, and holes depth on CFST stub columns. The typical failure modes, load‐deformation responses, the ultimate strength, and ductility were discussed in detail. A total of twenty‐eight specimens, twenty CFST columns with holes, four intact CFST specimens, and four reference hollow steel tubes subjected to axial compressive loading, were tested. The experimental results were compared with predictions of Eurocode 4 and finite element analysis. An empirical equation for predicting the ultimate strength of CFST stub columns with holes was proposed.

Failure Prediction of Composite Open Hole Tensile Test Specimens Using Bond Based Peridynamic Theory

In this study, interaction of holes in different locations in a tensile loaded composite plate is analysed using Bond-Based Peridynamic (PD) Theory. Moreover, the crack growth behaviour in the plate is investigated. PD simulations are conducted using adaptive dynamic relaxation solution scheme using a code developed in MATLAB. The PD solutions of the crack tip opening displacement is validated with the results obtained through finite element analysis (FEA) using ANSYS. The crack propagation paths and the effect of hole interaction on crack growth behaviour are also investigated using PD theory. Results obtained using PD theory were compared with the results of FEA and Özaslan et al. (2019). It is found that PD can accurately capture stress, strain and hole interactions in composite laminates.

Padded Coprime Arrays for Improved DOA Estimation: Exploiting Hole Representation and Filling Strategies

As a generalized coprime array structure, the coprime array with displaced subarrays (CADiS) allows a large minimum inter-element spacing by introducing a specific displacement between two sparse subarrays. While this structure can effectively reduce mutual coupling, the holes in its difference co-array greatly decrease the achievable number of uniform degrees of freedom (DOFs). In this paper, we first provide a complete characterization for the hole locations in the difference co-array generated by a tailored CADiS (tCADiS) as the union of four subsets of locations related via simple symmetry properties. We then introduce two representation approaches for the hole locations, revealing that the latter can be generated from the differences between sensor locations in the subarray of tCADiS and a small uniform linear array, referred to as a padded subarray. Subsequently, we propose novel padded coprime arrays (PCAs) by incorporating the padded subarray into tCADiS to enlarge the consecutive segments in the difference co-array. This not only contributes to increase the number of available uniform DOFs, but also helps mitigating the mutual coupling by limiting the number of sensor pairs with small separations. Finally, numerical simulation results are provided to demonstrate the superiority of PCAs over existing sparse array configurations in terms of DOF, mutual coupling and DOA estimation accuracy.

Experimental investigation of film cooling effectiveness on a gas turbine blade pressure surface with diffusion slot holes

The film cooling effectiveness of diffusion slot hole was experimentally examined using pressure sensitive paint technique at a low-speed linear cascade. As a comparison, the film cooling effectiveness of fan-shaped hole was also measured. The mainstream Mach number at the cascade inlet and outlet was 0.1 and 0.19, respectively. The effects of blowing ratio, density ratio and hole location on the film cooling effectiveness were investigated. The experimental results demonstrated that the film cooling effectiveness of diffusion slot hole is obviously higher than that of fan-shaped hole. The difference of area-averaged effectiveness from surface arc length-to-hole diameter ratio of S/D = 1 to S/D = 30 between the two film hole schemes is maximum at first row, and the absolute increment is over 0.2 when the blowing ratio is larger than 1.0. The increase of blowing ratio elevates the film cooling effectiveness of the diffusion slot hole. Generally, the farther the film hole away from the blade leading edge, the higher the film cooling effectiveness. Meanwhile, the diffusion slot hole shows less sensitivity to film hole location compared to fan-shaped hole. In addition, the elevating density ratio leads to a positive influence on the film cooling effectiveness of diffusion slot hole.

Accuracy of mandible-independent maxillary repositioning using pre-bent locking plates: a pilot study

The double splint method is considered the gold standard for maxillary repositioning, but the procedure is lengthy and prone to error. Recent splintless methods have shown high repositioning accuracy; however, high costs and technical demands make them inaccessible to many patients. Therefore, a new cost-effective method of mandible-independent maxillary repositioning using pre-bent locking plates is proposed. Plates are bent on maxillary models in the planned position prior to surgery. The locations of the plate holes are replicated during surgery using osteotomy guides made from thermoplastic resin sheets. Pre-bent plates are subsequently fitted onto the maxilla, and plate holes are properly set to reposition the maxilla. The purpose of this study was to evaluate the accuracy of this method for maxillary repositioning and the reproducibility of the plate holes. Fifteen orthognathic surgery patients were evaluated retrospectively by superimposing preoperative simulations over their postoperative computed tomography models. The median deviations in maxillary repositioning and plate hole positioning between the preoperative plan and postoperative results were 0.43mm (range 0–1.55mm) and 0.33mm (range 0–1.86mm), respectively. There was no significant correlation between these deviations, suggesting that the method presented here allows highly accurate and reliable mandible-independent maxillary repositioning.

Selective transport and separation of charge–carriers by an electron transport layer in NiCo2S4/CdO@CC for excellent water splitting

Here, we propose an approach to inhibit interfacial charge recombination by an electron transport layer (ETL) that selectively transports electrons and simultaneously restricts the passage of holes. The ETL is embedded as a junction between a photocatalyst (NiCo2S4/CdO) and an electron collector (carbon cloth (CC)). The electron density gradient, band gap offset, and p–orbital states above the fermi level in the ETL regulate the directional flow of electrons from NiCo2S4/CdO to CC. The distinct locations of electrons and holes were confirmed based on the oxidation state and preferential deposition of platinum and lead ions on NiCo2S4/CdO@CC. The molecular orbitals and density of states and their relation to ETL’s performance were explained using first principles calculations. Reduction in recombination energy loss was supported by the Nyquist and Bode phase analyses. ETL’s inclusion resulted in a remarkable 77 % increase in H2 yield, suggesting that they have excellent potential for practical applications.

Fuel-air mixing process of low pressure direct injection in a side ported rotary engine

Stratification is seen as a prominent technique for improving the performance of spark ignition engines especially at part loads. Though rotary engines have high specific power, they suffer high fuel consumption and HC emission. For this reason, direct injection methods in rotary engines have been investigated since they were introduced to the market. In this study, early direct injection in a side ported rotary engine was investigated by using CFD techniques. The aim of the study is to obtain the potential of low pressure direct injection method on mixture formation process. Geometrical model of Mazda Renesis engine that were modified as a single rotor engine for research activities was used in the modeling studies. Fuel was injected directly to the chamber from present oil hole location that has less geometrical constraints than any other location of the Renesis engine. Simulations were done for 2000 rpm which is a typical part load operation point of the engine. In numerical calculations, RNG k-ε model was used as the turbulence model; spray breakup was modeled by the Taylor Analogy Breakup (TAB) model. Flow pattern of intake air and fuel droplet distributions were investigated for a possibility of having rich mixture around spark plugs. The results showed that swirl-like motion of the side ported engine inhibits fuel spray to accumulate in the middle of the combustion chamber. Fuel droplets were driven to the counter side of the inlet wall by centrifugal force of the inlet air. This effect reduced as the swirl flow diminishes due to sweeping motion of the rotor. It is observed that the main flow in the chamber is converted to the tumble-like flow at middle and last part of the compression stroke.

Hydrogen photogeneration using ternary CuGaS2-TiO2-Pt nanocomposites

In this contribution we synthesized ternary CuGaS2-TiO2-Pt materials. The semiconductor components were surface functionalized with mercapto-alifatic acids to drive their linking and were platinized prior to or after contact between the semiconductors. The corresponding samples were utilized in the photo-production of hydrogen using methanol as a sacrificial agent. The testing under UV and visible illumination conditions together with the calculation of the true quantum efficiency of the process demonstrate the outstanding performance of these ternary materials under sunlight operation. Optimum activity was achieved for samples having a 3 to 5 wt % of the chalcogenide and a selective interaction of the noble metal with the major oxide component. The physico-chemical characterization and particularly the use of photoluminescence spectroscopy showed that photo-activity is controlled by charge separation under illumination, which drives to charge location of electrons and holes in different components of the powders and the efficient use of charge carriers in the chemical reaction.

Early plant development depends on embryo damage location: the role of seed size in partial seed predation

Seed predators sometimes inflict non‐lethal seed damage. We asked whether seed size modulates the location of insect seed damage and examined whether location‐specific damage on the embryo influences early plant development (embryo survival, germination, seedling emergence and performance). We used intact and weevil‐infested seeds of a prevalent California oak tree Quercus agrifolia as study model. We conducted observational and manipulative studies (simulate partial embryo damage).Seed size significantly affected the location of insect damage within the seed and, in turn, the probability of embryo damage, with larger seeds showing lower probability of embryo damage. The location of the larva exit hole was strongly associated with the probability of embryo damage, with 0.9 probability when the exit hole is located <5 mm from the embryo.Partial damage on the embryo was found in ca 11% of the infested seeds (n = 250). Among them, 63% showed damage only on the inner part (plumule) of the embryo. Damage on the plumule (the rudimentary shoot) was more lethal than damage on the radicle, particularly at the emergence phase, when success rate of plumule‐damaged seeds decreased by half as compared to that of radicle‐damaged seeds. Plumule‐damaged seeds also emerged much later and performed more poorly than radicle‐damaged seeds. Furthermore, seedlings that emerged from plumule‐damaged seeds showed poorer physiological parameters (lower chlorophyll and nitrogen content) than those emerged from radicle‐damaged seeds. Overall, intact seeds performed better than both types of damaged seeds.We highlight that seed size and its associated differential location of seed damage determines the occurrence of embryo damage and the region affected within the embryo (e.g. plumule versus radicle) which, in turn, affects important components of plant fitness. Different selective pressures affecting mostly the plumule (insects) versus the radicle (embryo‐clipping rodents) may contribute to elucidate the co‐evolutionary dynamics of seeds and their predators.

Bearing Capacity of Beams with Sinusoidal Corrugated Webs with Round and Square Holes

Steel beams with sinusoidal corrugated webs are known since the middle of the last century. Their bearing capacity is widely studied, the design rules of these beams are included in the existing regulations, such as "Standards European Committee for Standardisation (CEN): DIN EN 1993:2007-02, Eurocode 3: Bemessung und Konstruktion von Stahlbauten - Teil 1-5: Aus Blechen zusammengesetzte Bauteile", SNiP RK 5.04-23-2002 "Steel Structures. Design Standards." and SP 16.13330.2017 "SNiP II-23-81* Steel Structures". However, there is still an open question about the bearing capacity of sinusoidal corrugated webs of beams with holes bordered with steel sleeves to ensure the stability of the wall. In this paper, a method for calculating beams with sinusoidal corrugated webs, weakened by round and square holes, which are bordered by pipes is proposed. To develop this method of calculation a numerical experiment was conducted. A number of finite element models of such beams with varying web thickness, beam length, diameter and hole location were created and analyzed using the finite element method. ABAQUS computer complex was used for calculations. The result of the research conducted is a technique that makes it possible to determine the bearing capacity of sinusoidal corrugated webs of beams with round and square holes, bordered by pipes. To confirm the theoretical calculations, full-scale tests were carried out.

Analyzing the stress state of a thin-walled cylindrical tank, depending on the design features

The problem of the rational hole location on the surface of a thin-walled cylindrical gravity tank was studied in order to minimize the stresses around the concentrator. The studies were carried out for three cylindrical tanks with internal diameters of 250, 400 and 500 mm, respectively, with a height of 500 mm and a wall thickness of 20 mm. The diameter of the hole in the tank wall was varied as follows: 6, 10, 14, 18, 20, 23, 25, 30, 32, 36, 40, 45, and 50 mm. The holes were located on the lateral cylindrical surface of the tank, with the following variation of the location heights in relation to the total length of the cylinder element: 4/8, 3/8, 2/8, 1/8, 1/16, 1/32. As a result, it was determined that the increase of the internal diameter of a cylindrical tank increases the equivalent stress around the concentrator. Within some ranges, a change in the diameters of the hole does not actually affect the stress pattern. Using the holes of certain diameters can reduce the stresses around the concentrator.

Experimental and numerical investigations on the influence of cold expansion on low cycle fatigue life of bolt holes in aeroengine superalloy disk at elevated temperature

The direct mandrel cold expansion was introduced to bolt hole locations for a nickel based superalloy compressor disk of an aeroengine in order to improve its fatigue performance at elevated temperature. Low cycle fatigue tests on plate specimens were carried out at 600 °C, revealing the average lives of cold expanded samples increased by 2.1–3.5 times. Fracture surfaces were examined using the scanning electron microscope, together with the X-ray diffraction method to measure the residual stresses. Based on three-dimensional finite element analysis, the proposed life model gave satisfactory results with the maximum mean absolute error being 25.7%.

Galvanized RHS X-Connections. I: Effects of vent and drain holes on SCFs

For galvanizing of welded tubular steel trusses, sufficiently large holes to allow for quick filling, venting and drainage must be specified to mitigate the risk of damage. These holes, quite often specified at the hot spot stress locations recommended by the current design guides, will inevitably affect the fatigue behaviour of the connection. In this research, six rectangular hollow section (RHS) connections, with varied hole location and brace-to-chord width ratio, were tested under brace axial loading. The stress concentration factors (SCFs) obtained from the experimental investigation were compared with those calculated using the formulae in CIDECT Design Guide 8. It was shown that the predictions based on the current formulae are unsafe. Hence, finite element (FE) models were developed and validated by comparison with the experimental data. A subsequent parametric study was conducted, including 192 FE models with varied hole location, brace-to-chord width ratio, chord width-to-thickness ratio, and brace-to-chord thickness ratio. Finally, SCF formulae for RHS connections with vent and drain holes at different locations were established based on the experimental and FE data.

A Research on Access of Load Carrying Capacity of Large Diameter Piles

The evaluation of load carrying capacity of piles needs the geotechnical properties, penetration tests, the nature of the subsoil both around and beneath the proposed pile, adequate description of rock to convey its physical behavior on borings, dead loads, live loads dimensions of the piles (length and diameter of pile). To compare the length and diameter response of bored cast in situ piles, the data required is obtained from the site of project name Four Laning Project of Nagpur-Saoner-Betul Section of NH-69. The subsoil profile of site shows the clayey and silty clayey soils at the top to the considerable depth underlying highly weathered sandstone. The water table is observed from 4.5 m below the ground level. Here it is not possible to provide shallow, raft foundation as the soil strata mostly clayey and silty clayey soils which have very less safe load bearing capacity. Hence deep foundation proposed for the work. Sufficient number of borings taken in accordance with IS: 1892. Study is done by using all these geotechnical engineering properties at all bore holes locations, varying length and diameters of piles for evaluation of load carrying capacities as per IS:2911 (Part 2) and IRC:78. The load carrying capacity for different diameter of piles and for different length of piles goes on increasing with the increase in diameter. The contribution of end bearing resistance increases up to 170%, whereas contribution of frictional resistance increases up to 40%. Theoretical settlement for different diameters of piles for 25m length of pile has been computed. It has been observed that the theoretical settlement for 1.2 m diameter pile for 25 m length of pile is found to be more than actual settlement obtained from pile test for the same dimensions of the pile. Since theoretical settlement prediction is within in permissible limit and greater than the settlement obtained from the actual pile load test data, the load – settlement designed using excel can be used by the geotechnical engineers for prediction of the load and settlement calculations.

Effect of central hole location in phakic intraocular lenses on visual function under progressive headlight glare sources

To analyze the effect of the central hole location in the V4c implantable collamer lens (ICL) on the quality of vision, including progressive headlight glare simulation and quality of life. IOBA-Eye Institute, Valladolid, Spain. Case series. The central hole location was determined by slitlamp and dual Scheimpflug imaging for 6months or more postoperatively. The visual acuity, mesopic contrast sensitivity, halogen glare contrast sensitivity, xenon glare contrast sensitivity, photostress recovery time after glare, de Boer scale, and Quality of Life Impact of Refractive Correction (QIRC) questionnaire results were evaluated. Multiple regression models were used to analyze the effect of the central hole location on parameters using the pupil center and visual axis as references based on Cartesian and polar coordinates. The safety index was 1.13 and the efficacy index, 1.12. Under all testing circumstances, central hole decentration did not affect the visual acuity or contrast sensitivity. With the visual axis as a reference, worse QIRC values were associated with greater upward central hole displacement (P=.03) and a lower polar angle value (P=.008); also, halogen glare discomfort was greater with a higher radius (P=.04). Using the pupil center as a reference, greater nasal central hole decentration was associated with longer xenon glare photostress recovery time (P=.002). Implantation of the ICL with a central hole yielded excellent visual outcomes, even under increasing glare sources, regardless of the hole's location. However, hole decentration might affect patient-perceived quality of life, bothersome halogen glare, and longer xenon glare photostress recovery time. Such complaints after the early postoperative period might be managed with discrete ICL centration if the central hole is decentered upward or nasally.

Studies on Quasi-Static and Fatigue Crack Propagation Behaviours in Friction Stir Welded Joints Using Peridynamic Theory

The friction stir welding (FSW) technology has been widely applied in aircraft structures. The heterogeneity of mechanical properties in weld and the hole in structure will lead the crack to turn. Peridynamics (PD) has inherent advantages in calculating crack turning. The peridynamic theory is applied to study the crack turning behaviour of FSW joints in this work. The compact tension (CT) samples with and without a hole are designed. The crack propagation testing under quasistatic and fatigue loads are performed. The peridynamic microplastic model is used and a three-stage fatigue calculation model is developed to simulate the quasistatic fracture and the fatigue crack growth. The results predicted by the peridynamic models are compared with the experimental ones. The effects of welding direction on quasistatic and fatigue crack propagation behaviours are investigated and the effect of hole position on crack path geometry is also studied. It is shown that the crack turning in FSWed CT samples can be captured by the peridynamic microplastic and the three-stage fatigue calculation models. The peridynamic crack growth rates agree with the experimental results. For CT specimen without a hole, the crack turns into the weld zone where the material is softer. The effect of welding direction on crack growth rates is not obvious. For CT sample with a hole, the crack propagation direction has been mainly controlled by the hole location and the welding direction has a slight effect on crack path.

Determining Biopore Infiltration Hole as Catchment Flood in Inundation Area Eastern of Makassar City Based on Geographic Information System (GIS)

The study aims to determine the suitable location of biopore infiltration holes by utilizing Geographic Information Systems Software (GIS) in adopting appropriate technologies Biopore Infiltration Hole (LRB) at inundation areas in the eastern city of Makassar. The analysis of this study is conducted in the form of qualitative analysis which to identify the type of soil in the research and as well as quantitative analysis to determine the suitable location applied in Biopore Infiltration Hole (LRB). In the outline, the concept of applying the analysis technique of super-impose with the three variables of determining analysis location of Biopore Infiltration Hole (LRB) such as soil type, rainfall and built coefficient region. The results of this study indicate that the three sites are suitable to be applied Biopore Infiltration Hole (LRB), namely; location IV (RT 3 RW 6 Berua), location V (RW 7 Mangga Tiga) and the location VI (RW 16 Blok Ae BTP) in Paccerakkang village which each location requires a number of absorption biopore holes as much as 84,417 for IV location, 6,894-6,644 locations V and VI for the location.The utilization of GIS Software in implementing Biopore Infiltration Hole (LRB) obtained a map view location which is suitable to be applied for biopore hole absorptions and the number of needs in the region.