Base Plate Research Articles

NUMERICAL INVESTIGATIONS ON THE FREE SURFACE FLOW AROUND WING-BODY JUNCTIONS

Starting with January 2013, all ships greater than 400 tons engaged in international voyages must comply with the Energy Efficiency Design Index (EEDI), and starting with January 2023 also with the Efficiency Existing Ship Index (EEXI), issued by the International Maritime Organization, (IMO). Knowing that, in general, a ship hull is the result of a compromise between the main dimensions imposed by the size of the locks, navigation route depth, port depth, taxes, transport capacity (deadweight, volume), ship equipment (machinery, deck installations, piping systems), hydrostatic performances and last but not least the hydrodynamic performances, from ship hydrodynamics point of view the available approaches are the optimization of the ship size and hull forms or the design of propellers adapted to the ship's wake. The main purpose is to reduce the ship resistance and increase the efficiency of the propulsion system which ultimately leads to a reduction in the power placed on board the ship. For this, there can be used the so-called flow control devices or Energy Saving Devices (ESD hereafter), as hydrofoils or nozzles, to improve the flow parameters entering the propeller disc in order to increase the efficiency of the propulsion system and decreasing the fuel consumption leading to reducing of the carbon and greenhouse gasses emissions. For ballast loading condition the ESD may intersect the free surface, the flow becoming complicated and combining nonlinear, three-dimensional and turbulent phenomena such as the boundary layer on solid surfaces, the horseshoe vortex system developed around junctions and their effects turbulence, and also wave breaking. Therefore, this paper presents the results of the numerical study on the viscous free surface flow around junctions between a hydrofoil mounted on a plate, more precisely the study of the influence of the angle between hydrofoil and plate. It was observed that from a hydrodynamic point of view the angle between hydrofoil and base plate to be less than 15 degrees in respect to the vertical direction on the hydrofoil so that horseshoe vortex to be reduced in intensity and the value of the hydrofoil drag to be minimal.

Reliability-based design considering prediction interval estimation to optimize composite patches

A modified reliability-based design optimization (RBDO) technique was developed and applied to optimal designs of composite patches of a perforated base plate. The modified RBDO technique uses adaptive sampling strategies for the response surface method (RSM) to enhance the computational efficiency of the traditional RSM-based RBDO technique. Optimal design of composite patches was conducted for a perforated base plate using the newly proposed failure criteria which state that two conditions must be satisfied simultaneously for failure to occur. One condition is based on stress magnitude while the second condition is associated with the stress gradient. In other words, the failure criteria suggests that failure is more likely for higher stresses and lower stress gradients. Therefore, the design optimization of the composite patch was conducted to decrease the stress and to increase the stress gradient simultaneously at the edge of the perforated hole of the base plate in order to optimize the probability of failure of the base plate with composite patches.

Sensitivity of Melt Pool Size and Porosity Appearing to Base Plate Preheating in Laser Powder Bed Fusion Process

The base plate temperature ranks among the crucial building parameters whose effect on melt pool dimensions and porosity defects generation has not been sufficiently discussed in literature. In the current study, with the aim to explore the dependence between melt pool dimensions, porosity defects and base plate preheating, a 3-dimensional thermal finite element model is carried out to create IN718 single beads, at various base plate temperatures. The dimensions of the melt pool behave favourably with the base plate preheating. Indeed, the melt pool depth, width and length increase continuously with the heat of the base plate, from 20 °C to 500 °C. The melt pool width is more responsive to the base plate temperature than the melt pool depth. Numerical results also indicate that the melt dimensions become more responsive to the temperature of the base plate at a slower scan speed. The degree of porosity is predicted under multiple values of base plate temperature and the results show that porosity tends to disappear with further preheating of the base plate. A satisfying accordance between the numerical finding and the experimental results from literature is identified.

Peculiarities of the condition of the foundation slab of the pumped storage power plant water intake

The authors present the results of the analysis of field observations of the condition of the base slab of the water intake structure of hydroelectric power plant (including the stresses in the reinforcement in the areas of intersection with the vertical joints and the width of the opening of these joints). The aim of the study is to control the condition of the reinforced concrete structure of the foundation slab of the water inlet of the hydroelectric power plant, as well as to develop measures to strengthen the bottom section of the foundation slab in the areas of vertical interblock joints. In order to control the stress and strain of the base plate of the water intake of hydroelectric power plant, string control and measuring equipment was installed: on reinforcement rods - reinforcement dynamometers PSAS, on vertical interblock joints - displacement sensors PLPS. The field observations of the stress state of the reinforcement of the base slab of the water intake structure of hydroelectric power station showed that high values of tensile stresses, exceeding the design resistance of A500C class reinforcement (435 MPa), occurred in the reinforcement rods (directed along the flow), crossing the lower vertical interblock joints. There was also fixed the width of opening of the vertical interblock joint, reaching 1.28 mm. There was a necessity to strengthen the lower section of the foundation slab of the water intake structure of hydroelectric pumped storage power plant. For this purpose, inclined reinforcing bars (anchors) crossing the lower vertical interblock joints were installed. The outlet sections of the buttresses of the slab of the downstream section of the inlet to the downstream parapet were increased.

Experimental investigation of low-velocity impact behavior and CAI on composite laminates by discrete interleaved toughening

A novel damage tolerance design method of discrete interleaved toughening for laminated composite was proposed. In this paper, discrete thermoplastic Polyamide-6,6 (PA 66) films were deployed at between the selected adjected layers, and three toughening dimensions were considered. Besides, three impact positions of specimens were tested under 5 J, 10 J, and 15 J, respectively. The impact behavior and compression after impact (CAI) of specimens were discussed and compared. Experimental results showed that delamination damage was suppressed in the process of propagation outwards across the toughened region, and the path of delamination crack propagation was changed and swerved. Therefore, the delamination damage projected area (DDPA) of all specimens were reduced by 21.09%–62.85%, compared with the non-toughened plate (base plate). In addition, the finding demonstrated that CAI strength is influenced by the delamination position and DDPA. The proposed method could improve the CAI strength by suppressing delamination and swerving the propagation path of delamination. Moreover, the CAI strength of all toughened plates were improved by 16.35%–61.94% in contrast to the related base plates.

Anisotropy of the friction forces of rest and sliding frictionof single crystals of ice

The properties of the ice of natural reservoirs are due to its crystalline structure. The dependence of the mechanical and strength characteristics of single ice crystals on the angle between the direction of application of force to a single crystal and the direction of its C-axis is known. Basically, this dependence is due to the possibility of the base plates of a single crystal of ice sliding relative to each other. In physics, in addition to the mechanical and strength characteristics of a solid, the properties of the surfaces of a solid state, manifested in the process of friction, are of great importance. The friction of two single crystals of ice relative to each other has been investigated in experiments on rest friction and sliding friction. From an artificially grown plate of a single ice crystal, samples of single crystals of ice with a certain orientation of the C-axis were made for the experiment. The measurement of the rest friction coefficient of a single ice crystal was realized according to the classical scheme of recording the minimum angle at which the single crystal began to roll down an inclined surface. The dependence of the rest friction coefficient of ice single crystals on the mutual orientation of the C-axes of single crystals relative to each other was discovered. The coefficients of rest friction in the case that the C-axes of single ice crystals are parallel to each other significantly exceed those obtained when the C-axes of single ice crystals are perpendicular to each other. Measurements have shown that the anisotropy of sliding friction increases with increasing initial velocity of the single crystal on the surface of the second single crystal. This is explained by the fact that with the growth of the path traveled by the M2 crystal, the time of interaction of single crystals of ice also increases, during which the properties of the anisotropy of single crystals of ice relative to sliding friction are manifested. Studies have shown the presence of anisotropy of the friction forces of rest and friction of sliding of a pair of single crystals of ice.

In Vitro and Pre-Clinical Evaluation of Locally Isolated Phages, vB_Pae_SMP1 and vB_Pae_SMP5, Formulated as Hydrogels against Carbapenem-Resistant Pseudomonas aeruginosa.

The inadequate therapeutic opportunities associated with carbapenem-resistant Pseudomonas aeruginosa (CRPA) clinical isolates impose a search for innovative strategies. Therefore, our study aimed to characterize and evaluate two locally isolated phages formulated in a hydrogel, both in vitro and in vivo, against CRPA clinical isolates. The two phages were characterized by genomic, microscopic, phenotypic characterization, genomic analysis, in vitro and in vivo analysis in a Pseudomonas aeruginosa-infected skin thermal injury rat model. The two siphoviruses belong to class Caudovirectes and were named vB_Pae_SMP1 and vB_Pae_SMP5. Each phage had an icosahedral head of 60 ± 5 nm and a flexible, non-contractile tail of 170 ± 5 nm long, while vB_Pae_SMP5 had an additional base plate containing a 35 nm fiber observed at the end of the tail. The hydrogel was prepared by mixing 5% w/v carboxymethylcellulose (CMC) into the CRPA propagated phage lysate containing phage titer 108 PFU/mL, pH of 7.7, and a spreadability coefficient of 25. The groups were treated with either Phage vB_Pae_SMP1, vB_Pae_SMP5, or a two-phage cocktail hydrogel cellular subepidermal granulation tissues with abundant records of fibroblastic activity and mixed inflammatory cell infiltrates and showed 17.2%, 25.8%, and 22.2% records of dermal mature collagen fibers, respectively. In conclusion, phage vB_Pae_SMP1 or vB_Pae_SMP5, or the two-phage cocktails formulated as hydrogels, were able to manage the infection of CRPA in burn wounds, and promoted healing at the injury site, as evidenced by the histopathological examination, as well as a decrease in animal mortality rate. Therefore, these phage formulae can be considered promising for clinical investigation in humans for the management of CRPA-associated skin infections.

АНАЛИЗ ВЛИЯНИЯ РЕЖИМОВ ДВИЖЕНИЯ ЛЕСОВОЗНОГО ТЯГАЧА С ПОЛУПРИЦЕПОМ НА НАГРУЖЕННОСТЬ СЕДЕЛЬНО-СЦЕПНОГО УСТРОЙСТВА

The article presents the advantages of timber tractors with semi-trailers in comparison with single timber vehicles. The existing road condi-tions for the operation of saddle road trains in-volved in the transportation of timber to con-sumers are described. The causes and conse-quences of loading elements of saddle-coupling devices of road trains are considered. The de-pendences of the change in forces in the cou-pling device on the values of the coefficients of adhesion and the distribution of braking forces, the deceleration of the saddle road train, and also on the height of the center of gravity of the semi-trailer of the road train are presented. The regularities of changing the braking distance, deceleration and compression force in the fifth wheel coupling device of a road train due to un-derutilization of the coupling weight of a tractor with a semi-trailer are considered. The depend-ences of changes in loads in the fifth wheel cou-pling on road conditions, the load of the road train, the location of the fifth wheel coupling on the tractor, as well as on the damping coefficient are analyzed. An analysis of oscillograms of changes in forces in the pivot of the device in the process of sharp braking on a curvilinear and rectilinear trajectory with various options for braking by individual links is given. The influ-ence of the road train load, the speed of its movement, the type of road surface, the design parameters of the coupling device, the presence of lubricant on the base plate, the level of its wear on the change in the moment of resistance in such a device are described. The necessity of increasing the efficiency of timber tractors with semi-trailers by improving the existing designs of fifth wheel couplings is substantiated.

Effect of concrete edge distance on the hysteretic response of roof joint

SummaryRoof joint connects the upper roof structure to the lower RC columns in large‐span structures. However, during several earthquakes, concrete edge failure of roof joint observed in several previous earthquakes shows potential collapse damage of the large‐span structures. This paper presents an experimental and numerical study on the performance of roof joints under quasi‐static cyclic loading. The effects of concrete edge distance of anchor rods and using horizontally slotted holes in the base plate were investigated and discussed by means of ultimate shear resistances, failure modes, hysteretic responses, anchor strains, and stirrup strains. It was found that concrete edge failure was prone to occur if the edge distance was taken as per current design practice. However, with the use of slotted holes in the base plate, the concrete edge failure could be suppressed due to the sliding between the base plate and the mortar layer. A refined theoretical model was proposed to evaluate the ultimate shear resistance and predict the failure mode. Finite Element Models (FEMs) were also developed to verify the proposed theoretical model in terms of the ultimate shear resistance and the failure mode under both monotonic and cyclic loading.

Modelling, Temperature Analysis, and Mechanical Properties of Friction Stir Welding of Al-Cu Joints with Hardened OHNS Steel Tools

Friction stir welding (FSW) is a nearly modern welding method with vital advantages over the conventional welding process, such as lower distortion, enhanced mechanical properties, and eco- friendly. In FSW, the joint characteristics mainly depend on heat development during the joining process due to its solid-state joining method. The basic principles of thermomechanical methods during FSW are unknown since it is a new metal joining method. In this investigation, the 2D and 3D models of the tools with different pin forms were designed using SOLIDWORKS. The ANSYS software was used to investigate the temperature distributions near the weld zones. The fixture was designed and made according to the machine conditions. The base plates used were AA6101 and C11000; the tool material used was the Hardened OHNS steel tool with square and circular pin form. The temperature values were measured in each trial while joining of Al-Cu base plates along the weld line. The results reveal that in the joint area, a trial with high temperature leads to high ultimate tensile strength (UTS) and Charpy impact strength (CIS). Made at tool rotation speed 1200 rpm and feed velocity 20 mm/min of Hardened OHNS steel tool with circular pin form. The obtained UTS value at joints was less than that of Al and Cu base plates. The microhardness value detected at the joint area was higher than the Al and Cu base plates, providing high strength, and irregularly dispersed.

Design and Optimization of Friction Stir Welding of Al-Cu BUTT Joint Configuration using Taguchi Method

Friction stir welding (FSW) is a solid-state welding technique in which the joint quality was predominantly subjected to heat formation throughout the metal welding process. The weld joint produced from FSW was better than the other fusion welding process. In this research, the base plates AA6101 and C11000 of 5 mm thickness were joined using the hardened oil-hardened nonshrinkable steel(OHNS) tool by the FSW method. The design of experiment (DOE) was used to optimize the input parameters such as tool rotational speed (rpm), feed rate (mm/min), and tool pin offset (mm) on output parameter ultimate tensile strength (UTS). The design of experiment (DOE) was carried out by employing a Taguchi L9 orthogonal array, three factors, and three levels for obtaining a quality joint with good strength. The results of nine trial runs from the Taguchi experimental approach were formulated and analyzed using the statistical tool analysis of variance (ANOVA) using MINITAB 19 software. ANOVA analysis was employed to find the contribution of the input parameters toward the output. The optimized input process parameters will help to create effective weld joints. This study revealed that tool pin offset towards softer metal at medium tool rotational speed would create joints with the highest UTS. Scanning Electron Microscope (SEM) was applied to investigate the structural changes in the FSW of Al-Cu joints.Friction stir welding (FSW) is a solid-state welding technique in which the joint quality was predominantly subjected to heat formation throughout the metal welding process. The weld joint produced from FSW was better than the other fusion welding process. In this research, the base plates AA6101 and C11000 of 5 mm thickness were joined using the hardened oil-hardened nonshrinkable steel(OHNS) tool by the FSW method. The design of experiment (DOE) was used to optimize the input parameters such as tool rotational speed (rpm), feed rate (mm/min), and tool pin offset (mm) on output parameter ultimate tensile strength (UTS). The design of experiment (DOE) was carried out by employing a Taguchi L9 orthogonal array, three factors, and three levels for obtaining a quality joint with good strength. The results of nine trial runs from the Taguchi experimental approach were formulated and analyzed using the statistical tool analysis of variance (ANOVA) using MINITAB 19 software. ANOVA analysis was employed to find the contribution of the input parameters toward the output. The optimized input process parameters will help to create effective weld joints. This study revealed that tool pin offset towards softer metal at medium tool rotational speed would create joints with the highest UTS. Scanning Electron Microscope (SEM) was applied to investigate the structural changes in the FSW of Al-Cu joints.

Laser Powder Bed Fusion of Intermetallic Titanium Aluminide Alloys Using a Novel Process Chamber Heating System: A Study on Feasibility and Microstructural Optimization for Creep Performance

A laser powder bed fusion process operating at elevated temperatures is introduced capable of fabricating crack-free and dense intermetallic titanium aluminide alloy specimens as well as demonstrator components using a base plate heating up to 900 °C and a unique heating system of the uppermost powder bed layer up to 1200 °C. Two so-called 4th generation alloys, TNM and TNM+, were used for this study. The microstructure and its evolution during subsequent heat treatments were investigated and explained by employing scanning electron microscopy, hardness testing, X-ray diffraction, differential scanning calorimetry and thermodynamic equilibrium calculation. Selected specimens were subjected to creep tests at 750 °C. The microstructures after processing consist of extraordinarily fine lamellar γ-TiAl/α2-Ti3Al-colonies with globular γ and βo-TiAl grains for both the TNM and TNM+ alloy, exhibiting a microstructure gradient from the last consolidated powder layer down to the starting layer due to cellular reaction, which increases the amount of globular γ and βo at the boundaries of the γ/α2-colonies. During annealing in proximity to the γ-solvus temperature, banded microstructures might form, as the α-grain size is only partially controlled by heterogeneously distributed γ/β-phase, which stems from the process-related Al loss. Additionally, the occurrence of thermally-induced porosity is investigated. Optimizing the microstructure to a homogenized, almost fully lamellar microstructure, involved annealing in the β-single phase field region and led to improved creep properties. Finally, TNM demonstrator components with complex geometries, such as aero engine blades and turbocharger turbine wheels, are fabricated by employing the novel laser powder bed fusion process.

Profile of The Incidence of Onychomycosis at RSUD Dr RM Djoelham Binjai for Period January 2017 – December 2021

Onychomycosis is a disease caused by a fungal infection of the base plate and nail matrix which can be caused by dermatophytes, candida and other fungi. This study is a retrospective descriptive study to describe the results of the onychomycosis patient identification examination. The population in this study were all patients with new onychomycosis visits recorded in the medical record data of RSUD Dr. RM Djoelham Binjai for the period January 2017 – December 2021 which matched the inclusion criteria. Data collection uses secondary data with total sampling technique. The results showed that the highest prevalence of onychomycosis patients aged 51-60 years was 12 patients (30.8%), the average female sex was 23 patients (58.9%) and work as a farmer was 16 patients (40.5%). It is recommended to patients to always maintain personal hygiene and from damp and closed conditions.

Identification and dynamics of coherent structures in a Coanda swirling jet flow

Swirl stabilised flows are the most common technology for gas turbine combustion stabilisation. Although success on the characterisation of these flows is tangible, there are several structures that appear in such flows that are still a concern for fundamental and applied research. One of these structures is the Precessing Vortex Core (PVC), whose ambiguous characteristics make it an adequate mechanism for chemical mixing whilst being a detrimental component for thermoacoustic stabilisation. The PVC has been extensively characterised in swirling jet flows exhibiting vortex breakdown (in this study named Open Jet Flow or OJF). However this has not been the case for swirling Coanda (i.e. wall attached) Jet Flows (CoJF). Therefore, this research presents experimental work detailing the identification and visualisation of coherent structures in both types of jet flows. A generic swirl burner was fitted with a base plate in a position so that any of these two flows, OJF and CoJF, could be obtained within the same burner geometry. High speed stereo particle image velocimetry (S-PIV) was used to obtain a time-resolved flow field of each flow state at different flow rates. Two PVCs were clearly identified in both flows, one in the inner shear layer between the vortex breakdown bubble and the jet and one between the jet and the ambient. Precessing frequencies for the CoJF where ∼8.5% higher (St ∼0.9-1.0) than those of the OJF (St ∼0.8-0.9). Spectral proper orthogonal decomposition was used to identify the coherent structures in the flow. Swirl strength (λci2) analysis was conducted on the coherent modes to establish quantitative and qualitative results and to produce a 3D reconstruction of the flow field. The results indicate that precessing coherent flow structures are present in wall attached Coanda swirling flows and these are similar to the structures found in swirling jet flows undergoing vortex breakdown.

Image Servo Tracking of a Flexible Manipulator Prototype with Connected Continuum Kinematic Modules

This paper presents the design and implementation of a flexible manipulator formed of connected continuum kinematic modules (CKMs) to ease the fabrication of a continuum robot with multiple degrees of freedom. The CKM consists of five sequentially arranged circular plates, four universal joints intermediately connecting five circular plates, three individual actuated tension cables, and compression springs surrounding the tension cables. The base and movable circular plates are used to connect the robot platform or the neighboring CKM. All tension cables are controlled via linear actuators at a distal site. To demonstrate the function and feasibility of the proposed CKM, the kinematics of the continuum manipulator were verified through a kinematic simulation at different end velocities. The correctness of the manipulator posture was confirmed through the kinematic simulation. Then, a continuum robot formed with three CKMs is fabricated to perform Jacobian-based image servo tracking tasks. For the eye-to-hand (ETH) experiment, a heart shape trajectory was tracked to verify the precision of the kinematics, which achieved an endpoint error of 4.03 in Root Mean Square Error (RMSE). For the eye-in-hand (EIH) plugging-in/unplugging experiment, the accuracy of the image servo tracking system was demonstrated in extensive tolerance conditions, with processing times as low as 58±2.12 s and 83±6.87 s at the 90% confidence level in unplugging and plugging-in tasks, respectively. Finally, quantitative tracking error analyses are provided to evaluate the overall performance.

A tensile stage for high resolution synchrotron-based infrared microspectroscopy at MIRAS

For the study of thin films and fibres under load, a uniaxial tensile stage has been developed for synchrotron-based polarized Fourier-transform infrared (FTIR) microspectroscopy. One of the advantages compared to commercial available stages is its compact design at the sample position (<20 mm thickness) and the large field of view on the sample for transmission and reflection geometry. In addition, the stage is mounted on a base plate, which can be rotated between -15° and +193° in the sample plane, in order to rotate the sample relative to the inherent polarization of the incoming infrared light from the synchrotron light source. Preliminary in situ tensile load experiments conducted at MIRAS beamline of the ALBA synchrotron were done on 3D printed thermoplastic polyurethane (TPU) polymer thin films. The samples could be mapped in transmission geometry under tensile load achieving high spatial resolution up to 10 micros using the intense IR source of the synchrotron light. Making use of polarized synchrotron-based infrared light, it was possible to show the alignment of different vibrational bands parallel and orthogonal to the stretching direction. The v(C=O) absorbance bands decrease upon stretching using parallel polarized infrared light, while the v(C=C) bands are increasing in intensity, revealing the orientation of v(C=O) bonds orthogonal to the stretching direction during stretching. The experiments highlight the unique instrumentation capabilities of the tensile stage for in situ measurement of molecular distributions and chemical bond orientations as a function of sample displacement and applied load.

Mechanical Action Mechanism and Crack Response Analysis of Slide Plate of No.12 Turnout

In the course of maintenance and repair, the railway workshops of the Lan-Qing railway found that the slide plate was prone to injury and damage. In order to study the actual stress state of the slide plate during the running of the train, a finite element model of the slide plate and related components was established based on ANSYS, Hypermesh was used for meshing and mesh quality control, and the Mooney-Rivlin constitutive intrinsic model was selected to simulate the rubber plate. The stress state of the slide plate when passing through the turnout in the straight and lateral directions is analyzed respectively. The results show that there is stress concentration at the root of the tongue depressor of the slide plate, and large deformation exists in the middle of the base plate, the front end of the platform plate and the position of the guide iron when passing through the turnout directly and laterally. The stress state of the slide plate is simulated when the rail brace fails, and the maximum stress is found to be 279.24 MPa, which exceeds the material yield limit. Therefore, we should pay attention to the inspection of the condition of the rail brace during the maintenance and repair. Presenting cracks at the weld seam location, it is found that the crack has a significant effect on the dewelding of the slide plate, and the heel position is the weakness of the slide plate. When the crack length reaches 1.2 mm, there is a tendency to crack at the weld seam position of the slide plate, and when the crack length continues to increase, the crack will further expand and jeopardizing structural safety. The research results can provide a theoretical basis for the improvement, disease prevention and maintenance of the slide plate.

INFLUENCE OF B4C AND TiN ON THE MICROSTRUCTURE AND WEAR BEHAVIOR OF FRICTION STIR PROCESSED AA7075 SURFACE COMPOSITE

Friction stir processing (FSP), which was the advancement in the friction stir welding technique, is thought to be an economic approach to alloying in the solid state that can be used to make composites. In this study, FSP was carried out to produce AA7075 (B4[Formula: see text]iN) composite by varying the composition of the reinforcement particles. Microstructural analysis was carried out and the homogenous distribution of the reinforced particles on the surface of AA7075 alloy was ensured. X-ray diffraction studies were carried out to analyze the phases present after fabricating the hybrid surface composites. Microhardness test was performed on the specimens before and after the fabrication process. Grain refinement in the friction stir processed zones was evidently seen in the optical microstructures. The combined effect of the ceramic powders and grain refinement led to increase in the microhardness in the hybrid surface composites compared with the base AA7075 plate. A 33.87% increase in microhardness was observed in the sample AA7075 reinforced with 75% B4C and 25% TiN. Wear testing was carried out at various loads (5, 10, 15 and 20 N) and at different sliding velocities (300, 350, 400 and 450 rpm) and the track distance was maintained at 1000 m. It was observed that the highest wear rate is [Formula: see text] cm3/Nm for the base plate AA7075 and the sample AA7075 reinforced with 50% B4C and 50% TiN shows the lowest wear rate of [Formula: see text] cm3/Nm. It is observed that the addition of B4C and TiN has resulted in a significant improvement in the wear resistance of the AA7075 alloy.

Analysis of coiling stable roll of hot-dip galvanized strip

The coiling stable roll of hot-dip galvanized is a defect formed in the galvanizing process. The zinc slags and floating foreign matters in the zinc pot will directly or indirectly adhere to the roll surface of the stabilizer roll with the flow of zinc liquid. When the strip steel contacts the stabilizer roll, the zinc slag will extrude and deform the iron base plate and form pits. In this paper. The causes of the defects were analyzed. There were two methods to eliminate the coiling stable roll, that is, to reduce the generation and accumulation of zinc slags in the zinc pot. The main measures are first to control the temperature of the strip entering the zinc can plate and the temperature of the molten zinc, and then control the amount of residual bottom residue before the zinc pot goes online. Another is to ensure the cleanliness of the steel strip before it enters the molten zinc. Based on this, the main measures implemented are: improving the cleaning ability of the cleaning section and improving the reducing ability during annealing to inhibit the formation and accumulation of zinc powder in the furnace head area.

Management of glenoid bone loss in primary reverse shoulder arthroplasty : a systematic review and meta-analysis.

Rates of reverse total shoulder arthroplasty (rTSA) continue to grow. Glenoid bone loss and deformity remains a technical challenge to the surgeon and may reduce improvements in patients' outcomes. However, there is no consensus as to the optimal surgical technique to best reconstruct these patients' anatomy. This review aims to compare the outcomes of glenoid bone grafting versus augmented glenoid prostheses in the management of glenoid bone loss in primary reverse total shoulder arthroplasty. This systematic review and meta-analysis evaluated study-level data in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. We performed searches of Medline (Ovid), Embase (Ovid), and PubMed from their dates of inception to January 2022. From included studies, we analyzed data for preoperative and postoperative range of motion (ROM), patient-reported functional outcomes, and complication rates. A total of 13 studies (919 shoulders) were included in the analysis. The mean age of patients at initial evaluation was 72.2 years (42 to 87), with a mean follow-up time of 40.7 months (24 to 120). Nine studies with 292 rTSAs evaluated the use of bone graft and five studies with 627 rTSAs evaluated the use of augmented glenoid baseplates. One study was analyzed in both groups. Both techniques demonstrated improvement in patient-reported outcome measures and ROM assessment, with augmented prostheses outperforming bone grafting on improvements in the American Shoulder and Elbow Surgeons Score. There was a higher complication rate (8.9% vs 3.5%; p < 0.001) and revision rate among the bone grafting group compared with the patients who were treated with augmented prostheses (2.4% vs 0.6%; p = 0.022). This review provides strong evidence that both bone graft and augmented glenoid baseplate techniques to address glenoid bone loss give excellent ROM and functional outcomes in primary rTSA. The use of augmented base plates may confer fewer complications and revisions.Cite this article: Bone Joint J2022;104-B(12):1334-1342.