Contact Plates Research Articles

An optimal design problem for an anisotropic elastic plate in a dynamic contact with an obstacle

AbstractWe deal with an optimal design problem governed by an initial‐boundary value problem for a hyperbolic variational inequality describing the perpendicular vibrations of a simply supported anisotropic elastic plate against a rigid obstacle. A variable thickness of a plate plays the role of a control variable. The admissible set of states for the design problem contains solutions of a state problem gained as limits of the sequences of functions solving penalized problems. We verify the existence of the optimal thickness function using the optimal controls achieved as solutions of optimal design problems connected with penalized state problems.

A Dual-Arm Robot That Manipulates Heavy Plates With the Support of a Vacuum Lifter

A vacuum lifter is widely used to hold and pick up large, heavy, and flat objects. Conventionally, when using a vacuum lifter, a human worker watches the state of a running vacuum lifter and adjusts the object&#x2019;s pose to maintain balance. In this work, we propose using a dual-arm robot to replace the human workers and develop planning and control methods for a dual-arm robot to raise a heavy plate with the help of a vacuum lifter. The methods help the robot determine its actions by considering the vacuum lifer&#x2019;s suction position and suction force limits. The essence of the methods is two-fold. First, we build a Manipulation State Graph (MSG) to store the weighted logical relations of various plate contact states and robot/vacuum lifter configurations, and search the graph to plan efficient and low-cost robot manipulation sequences. Second, we develop a velocity-based impedance controller to coordinate the robot and the vacuum lifter when lifting an object. With its help, a robot can follow the vacuum lifter&#x2019;s motion and realize compliant robot-vacuum lifter collaboration. Real-world experiments are carried out to investigate the proposed planning and control methods. The results show that a robot can effectively and flexibly work together with a vacuum lifter to manipulate large and heavy plate-like objects with the methods&#x2019; support. <i>Note to Practitioners</i>&#x2014;This paper is motivated by the vacuum lifters used for transporting heavy plates in a factory that produces building materials. In the factory, a human worker attaches the suction cup of a vacuum lifter to a plate and controls the vacuum lifter to pull the plate up. Meanwhile, another human worker moves and lifts the plate to a goal pose, following the vacuum lifter while maintaining balance. The job is dangerous as the plate is heavy, and the vacuum lifter is not always strong enough to hold the plate firmly. Inspired by the usage and safety problem, we in this paper develop a planning and control method for a dual-arm robot to replace humans. The robot coordinates its motion to work with the vacuum lifter and performs lifting tasks. The vacuum lifter could remain operated by a human worker or be actuated by signals from the dual-arm robot or other third-party machines. The work is complementary to our previous study that developed planners for robots to use pulley blocks. They together provide extensive knowledge for using low-payload collaboratively robots to manipulate heavy plates.

The interior penalty virtual element method for the fourth-order elliptic hemivariational inequality

We develop an interior penalty virtual element method (IPVEM) for solving a Kirchhoff plate contact problem, which can be described by a fourth-order elliptic hemivariational inequality (HVI). The virtual element space in IPVEM is constructed by modifying the H2-conforming virtual element space, and the number of degrees of freedom is greatly reduced. To force the C1 continuity, the interior penalty scheme is adopted, that is, we introduce a penalty term for the jump of normal derivatives on mesh edges and two additional terms to guarantee the consistency and symmetry of the scheme. With certain assumptions, the well-posedness of the discrete problem is proved. Furthermore, a priori error estimation is established for the IPVEM for the fourth-order elliptic HVI, and we show that the lowest-order VEM achieves optimal convergence order. Finally, some numerical examples are presented to support the theoretical results.

Novel airflow ring for the reduction of germ load in a surgical field

Abstract Hospital-acquired infections occur through microbial contamination of the surgical wound and can lead to severe complications. A significant transmission path is the aerogenic transmission, where pathogens stick to floating particles like skin scales or to air moisture. A novel porous airflow ring which is placed around the surgical field aims to overcome this by applying sterile air directly at the operation wound. The ring is provided with an air tight coating at the outer side and allows for fixation on the skin by an adhesive coating at the lower side. To evaluate its performance the airflow ring was placed in an atmosphere with nebulized suspension of Staphylococcus arlettae of a concentration of 5.0 x 10^5 CFU/ml resp. 5.0 x 10^6 CFU/ml within a box. The formation of bacterial colonies (CFU) on contact plates placed within the airflow ring was subsequently determined by visual counting after incubating at 37 °C for one day. CFU counts of the ventilated and the unventilated situation were compared. With the smaller inoculum, the introduction of bacteria into the inner site of the ring was completely prevented, whereas the contact plate of the unventilated ring resulted in 77 to 427 colonies in different trials. With the higher inoculum, the bacteria ingress was very strongly reduced by 99.7% respectively 99.9%. In conclusion the airflow ring shows a strong shielding effect for germs adhered to fog-sized water droplets. To clearly demonstrate the effect, the number of bacteria was greatly increased compared to reality in this setup. It was shown that it can withstand even conditions significantly worse than those encountered in an operating theatre. In order to demonstrate the effect in vivo, clinical trials have to be conducted to confirm the laboratory results.

STRESS ANALYSIS AND CHARACTERISTICS DUE TO THE SOUTH JAVA EARTHQUAKE, APRIL 10, 2021

The April 10, 2021, earthquake in the south of East Java was classified as destructive. The secondary impact of this earthquake was quite significant. Many houses collapsed, and not a few casualties. This earthquake is unique because usually, destructive earthquakes occur at shallow depths, but earthquakes with a magnitude of 6.1 are classified as medium-depth earthquakes at sea. The earthquake in the south of East Java is classified as an intraplate earthquake because it is located on the continental plate, not in the plate contact area. The question is whether the damage that occurred to the building was purely due to the magnitude of the stress released by the earthquake or whether there were other factors. This study uses seismogram data for the earthquake south of East Java on April 10, 2021, with a radius (∆) of 300-1000 recorded at MEEK, MORW, and ARMA stations in Australia. It calculates the amount of stress based on the stress drop, while the stress column determines the stress mechanism. Calculation of stress drop from the source spectrum is obtained by the deconvolution method, namely the seismogram component separation technique in the form of Source (f), Path (f), Site (f), and Instrument (f). The analysis of the observed displacement spectrum used the Nelder Mead Simplex nonlinear inversion method. Meanwhile, the Stress Columb calculation was obtained using the Columb 3.3 program from the United States Geological Survey (USGS). The result of this research is that the stress drop value is 1.69 MPa, with the type of focus mechanism being a thrust fault in the sea. The earthquake in the south of East Java was caused by rock activity in the intraplate. The value of the stress drop is more significant when compared to the subduction contact area. This area is of intraplate rock with various variations, and earthquakes are rare. This study aims to analyze the stress, both the magnitude of the stress drop and the mechanism of the column stress results, so that the stress caused by the earthquake can be known and why the earthquake in the south of East Java is destructive. The quake in Southeast Java is classified as dangerous, not because of the magnitude of the stress generated or its mechanism. The damage was due to the amplification of earthquake waves in the building. The injury occurred because most of the buildings were built on soft soil, especially in several areas in East Java, such as Lumajang, Pasuruan, Trenggalek, Probolinggo, Ponorogo, Jember, Tulunggagung, Nganjuk, Pacitan, and several urban areas, namely Blitar, Kediri, Malang, and Stone. So, there is a need for earthquake disaster mitigation, especially in densely populated areas that live on soft soil. This mitigation effort is to minimize the occurrence of casualties by building buildings according to earthquake-resistant standards and avoiding development in the regions that have the potential for amplification of earthquake waves.

Glove disinfection and aseptic technique: Creating a schema for the cleanroom and laboratory

There are different elements that contribute to good aseptic technique within the cleanroom and the laboratory. One such element is the donning of gloves (1), handling items appropriately, and keeping gloves regularly disinfected (2). Glove disinfection is an essential step for bacteriological control, although how successful control is maintained is dependent upon the type of disinfectant (these are generally alcohols for gloved hands) (3), frequency of application, volume of disinfectant, application technique and the contact time. Other variables include purchasing gloves of a suitable material and design, and appropriate training. Aa an added control with more critical areas, the gloves are pre sterilised before donning (often purchased sterile by radiation or ethylene oxide). As with other types of disinfection, the aim is not ‘sterilisation’ but to bring any bacterial density present on the gloves down to a level that is as low as possible (what is sometimes referred to as the "irreducible minimum") (4). Assessment, when required, is commonly through the use of agar contact plates onto the fingertips of each gloved hand (four fingers and the thumb) to create the ‘finger plate’ or ‘finger dab’. To avoid false negatives, the agar needs to be formulated with an appropriate disinfectant neutraliser. For cleanroom and laboratory managers seeking to maximise the maintenance of asepsis, glove control is an important element. This should take the form of a good practice schema and for this to be transitioned into a training module, supported by regular prompts in practice. In terms of what such a schema should look like, this article appraises the research that underpins an appropriate glove ‘sanitisation’ schema. This includes the central concerns of when and how effective glove disinfection is to be achieved (5). The key findings are that a 30 second disinfection time is suitable for both cleanroom and laboratory operations, provided a suitable technique is deployed and an alcohol-based disinfectant used. However, controls need to be in place to avoid the over disinfection of gloves since repeated applications increase the likelihood of microperforations occurring and thereby effective glove disinfection needs to be supported by a regular glove change procedure.

The Effect of Working Length, Fracture, and Screw Configuration on Plate Strain in a 3.5-mm LCP Bone Model of Comminuted Fractures

Abstract Introduction This study provides a comprehensive examination of plate strain under realistic fracture configurations. The effect of plate working length, plate contact, fracture length, and position on strain was evaluated using bone surrogates subjected to “load-controlled,” nondestructive conditions. Materials and Methods Five 3.5-mm locking compression plates (LCP) were instrumented with six strain gauges. The gauges were glued between holes in predetermined locations marked by laser engraving. Nine fracture models were created using bone surrogate, each representing a combination of the criteria under study: long versus short working length, degree of plate compression, fracture location, and fracture length. All five plates were tested under each of the nine configurations. The constructs were mounted in an Instron testing machine with a 5-kN load cell. Each specimen was cyclically loaded at a rate of 5 mm/min to 50, 100, and 200 N. Results Decreased plate strain was noted with a short plate working length in all fracture configurations (p &lt; 0.05). Increasing the plate working length increased the strain at higher loads and on the plate adjacent to the fracture gap. The size of the fracture gap and fracture location had minimal effects on plate strain (p &lt; 0.05). Elevation of the plate off the bone (1.5 mm) resulted in increased plate strain under all loading conditions (p &lt; 0.05). Conclusion Our null hypothesis was rejected in that a short plate working length resulted in decreased plate strain in all comminuted fracture configurations. Our secondary hypothesis was validated in that elevation of the plate from the bone resulted in increased strain in all configurations. As plate strain identifies regions of mechanical weakness whereby a construct may prematurely fail by acute overload or cyclic fatigue, identifying factors that may increase plate strain allows the surgeon to reduce these variables as much as possible to reduce the incidence of implant failure and subsequent fracture failure.

Pengaruh Teknik Pembekuan Ikan Tongkol (Euthynnus affinis) Terhadap Organoleptik di PT. Aceh Lampulo Jaya Bahari

Tuna contains high protein so that it fulfills the nutritional needs of the human body. Tuna is a marine fish that contains omega 3, vitamins, protein and minerals. This study aims to determine the effect of the freezing technique of tuna (Euthynnus affinis) on organoleptic at PT.Aceh Lampulo Jaya Bahari using a temperature of -30oC to -40oC with a freezing time of about 8 - 12 hours. Methods This study used a qualitative method consisting of research on the first with the influence of the technique of freezing tuna (Euthynnus affinis) with a comparison of 3 freezing methods, the second stage carried out an organoleptic analysis (ice layer, dehydration, discoloration, appearance, smell, texture.) on frozen tuna. The results of the value of the ice layer showed that the most preferred value by the analyst was the value of the semi contact plate freezer 7 ± 0.67 and cold storage 7 ± 0.67, the dehydration indicated the value most preferred by the analyst was the value of the semi contact plate freezer 7 ± 0.67 and cold storage 7 ± 0.67. The result of the value of dehydration shows the value most preferred by the analyst is the value of the semi contact plate freezer 7 ± 0.78. The result of the value of the appearance shows the value most preferred by the analyst is the value of air blast freezer 7 ± 0.50. the result of the value of the appearance shows the most preferred value by the analyst is the value of the air blast freezer 7 ± 0.50, the result of the value of the odor shows the most preferred value by the analyst is the value of the semi contact plate freezer 7 ± 0.41 and cold storage 7 ± 0.41, the value of the texture shows the most preferred value by the analyst is the value of air blast freezer 7 ± 0.25, semi contact plate freezer 7 ± 0.25 and cold storage 7 ± 0.25.

Tingkat Kandungan Histamin pada Ikan Cakalang (Katsuwonus Pelamis) dengan Metode Pembekuan yang Berbeda di CV. Novira Abadi Kota Banda Aceh

The fisheries sector in Indonesia has a greater potential, namely pelagic and demersal fish populations including skipjack tuna and tuna skipjack tuna are referred to as commodities that have high nutritional value but are easily damaged because they contain lots of protein which is high in free amino acids for microbial metabolism. production of ammonia, biogenic amines, organic acids, ketones and sulfur composition. Fish is one of the food products that is prone to deterioration in quality due to the action of enzymes or microbial growth. Handling of fresh fish can be done by applying cold temperatures through freezing techniques to prevent deterioration of fish quality. The SCF (semi contact plate freezer) method is a product freezing process between refrigerated shelves and this process takes place quickly. The use of semicontec in this product is fish arranged in a pan, which consists of 144 pans of cold air around the product with a temperature of - 40°C for 5 hours, with a temperature of 17.4°C in skipjack tuna, the histamine content was 0.3 ppm. ABF (Air Blast Freezer) freezing method. Freezing is done by placing the fish products that have been arranged in a pan and putting them into the ABF (air blast freezer) at the temperature used in the company, which is -35°C for 22 hours. in the arrangement of the fish that is included in the air blast freezer Freezing air blast freezer, which is a cold media made from freon that is used to freeze or ripen fish. The temperature of the fish after being frozen at air blast freezer 15.400C. by producing histamine levels in skipjack tuna 3.9 ppm, where the fish can still be consumed.

Study on Zn-doped antibacterial bioactive coatings on Ti6Al4V titanium alloy surfaces by micro-arc oxidation

To enhance the bioactivity and antibacterial activity of titanium alloys, coatings with different content of Zn element were successfully formed on Ti6Al4V substrates by micro-arc oxidation (MAO). The microstructure and composition of the coatings were characterized, and the bioactive and antibacterial activities were evaluated by the contact angle, cell viability and plate colony counting experiments, respectively. The results show that when Zn2+ concentration of the electrolytes rises, the breakdown voltage and the process voltage decrease, while the duration of the micro-arc oxidation stage increases. The products of MAO in the coatings are mainly rutile and anatase phases. As Zn2+ concentration in the electrolyte increases, the content of crystalline phases reduces, the thickness and the surface roughness of coatings increase, and the porosity shows an increase overall. MAO coatings bond tightly to the substrates, forming a thin, dense barrier layer and a thick, porous outer accumulation layer. The increase of Zn content results in an increase of Ca and P content in the coatings and a rise in Ca/P ratio. The concentrations of Ti, O, Ca and Zn elements on the cross-section show a transition distribution. Moreover, the hydrophilicity of all coatings is improved. Zn-doped coatings improve the cell viability of preosteoblast MC3T3-E1 cells and macrophage RAW264.7 cells, and higher cell viability is observed on the coatings with higher Zn concentration. Although the MAO coatings with low Zn content increase bacterial adhesion compared to the substrate, the coatings with high Zn content show adequate antibacterial activity.

Parameter optimization in a finite element mandibular fracture fixation model using the design of experiments approach

Only a few mandibular bone finite element (FE) models have been validated in literature, making it difficult to assess the credibility of the models. In a comparative study between FE models and biomechanical experiments using a synthetic polyamide 12 (PA12) mandible model, we investigate how material properties and boundary conditions affect the FE model's accuracy using the design of experiments approach.Multiple FE parameters, such as contact definitions and the materials' elastic and plastic deformation characteristics, were systematically analyzed for an intact mandibular model and transferred to the fracture fixation model. In a second step, the contact definitions for the titanium screw and implant (S–I), implant and PA12 mandible (I-M), and interfragmentary (IF) PA12 segments were optimized. Comparing simulated deformations (from 0 to −5 mm) and reaction forces (from 10 to 1′415 N) with experimental results showed a strong sensitivity to FE mechanical properties and contact definitions. The results suggest that using the bonded definition for the screw-implant contact of the fracture plate is ineffective. The contact friction parameter set with the highest agreement was identified: titanium screw and implant μ = 0.2, implant and PA12 mandible μ = 0.2, interfragmentary PA12 mandible μ = 0.1. The simulated reaction force (RMSE = 26.60 N) and surface displacement data (RMSE = 0.19 mm) of the FE analysis showed a strong agreement with the experimental biomechanical data. The results were generated through parameter optimization which means that our findings need to be validated in the event of a new dataset with deviating anatomy.Conclusively, the predictive capability of the FE model can be improved by FE model calibration through experimental testing. Validated preoperative quasi-static FE analysis could allow engineers and surgeons to accurately estimate how the implant's choice and placement suit the patient's biomechanical needs.

Product Refrigeration Load Analysis On Contact Plate Freezer On Compressor Performance At PT. Trimitra Makmur, Tarakan, North Kalimantan

Contact plate freezer (CPF) is a cooling machine unit for freezing products which of course will maintain product freshness. In Order to runs smoothly, one thing that must be considered of the cooling system is the cooling load on the freezer contact plate. The cooling load is the amount of heat absorbed per unit time. The refrigeration cycle at PT. Trimitra Makmur uses a combined refrigeration cycle (multi-stage cycle), uses two cycles of vapor compression using two single-stage compressors. The two compressors used have the same power of 55.92 kW. The cooling load on the contact plate freezer consists of product heat load, water heat load, internal heat load, and transmission heat load. In The contact plate freezer, infiltration or heat load from the outside air are not counted because during production the contact plate freezer door is closed tightly so that the air exchange value is very small and can be neglected. In this study, the average total load on contact plate freezer 1 was 23.07079 kW, so that the average total load on the three contact plate freezers at PT. Trimitra Makmur is 69.21237 kW. The results of data collection and calculations show that the COP (Coefficient of Performance) value for the high-stage cycle is 4.33, so that the high-stage compressor power used is 1/4.33 of the cooling capacity of the contact plate freezer. Whereas in the booster cycle, a COP of 6.49 was obtained, so that the booster compressor power used was 1/6.49 of the cooling capacity of the contact plate freezer. &#x0D;

Investigation of microstructure of fretting wear behavior in 6061-T6 aluminum alloy

PurposeThe purpose of this study is to investigate the microstructure of fretting wear behavior in 6061-T6 aluminum alloy. The fretting wear of blind riveted lap joints of 6061-T6 aluminum alloy plates, which are widely used in aircraft construction, was investigated. Fretting damages were investigated between the contact surface of the plates and between the plate and the rivet contact surface.Design/methodology/approachExperiments were carried out using a computer controlled Instron testing machine with 200 kN static and 100 kN dynamic load capacity. Max package computer program was used for the control of the experiments. Fretting scars, width of wear scars, microstructure was investigated by metallographic techniques and scanning electron microscopy.FindingsIt was found that fretting damages were occurred between the plates contacting surface and between the plate and rivet contact surface. As load and cycles increased, fretting scars increased. Fretting wear initially begins with metal-to-metal contact. Then, the formed metallic wear particles are hardened by oxidation. These hard particles spread between surfaces, causing three-body fretting wear. Fretting wear surface width increases with increasing load and number of cycles.Originality/valueThe useful life of many tribological joints is limited by wear or deterioration of the fretting components due to fretting by oscillating relative displacements of the friction surfaces. Such displacements are caused by vibrations, reciprocating motion, periodic bending or twisting of the mating component, etc. Fretting also tangibly reduces the surface layer quality and produces increased surface roughness, micropits, subsurface microphone.

Variation of Fault Creep Along the Overdue Istanbul‐Marmara Seismic Gap in NW Türkiye

AbstractStrain energy from tectonic loading can be partly released through aseismic creep. Earthquake repeaters, repeatedly activated brittle fault patches surrounded by creep, indicate steady‐state creep that affects the amount of seismic energy available for the next large earthquake along a plate contact. The offshore Main Marmara Fault (MMF) of the North Anatolian Fault Zone represents a seismic gap capable of generating a M &gt; 7 earthquake in direct vicinity to the mega‐city Istanbul. Based on a newly compiled seismicity catalog, we identify repeating earthquakes to resolve the spatial creep variability along the MMF during a 15‐year period. We observe a maximum of seismic repeaters indicating creep along the central and western MMF segments tapering off toward the locked onshore Ganos fault in the west, and the locked offshore Princes Islands segment immediately south of Istanbul in the east. This indicates a high degree of spatial creep variability along the Istanbul‐Marmara seismic gap.

Nanosilver/DCOIT-containing surface coating effectively and constantly reduces microbial load in emergency room surfaces

Colonization of near-patient surfaces in hospitals plays an important role as a source of healthcare-associated infections. Routine disinfection methods only result in short-term elimination of pathogens. To investigate the efficiency of a newly developed antimicrobial coating containing nanosilver in long-term reduction of bacterial burden in hospital surfaces to close the gap between routine disinfection cycles. In this prospective, double-blinded trial, frequently touched surfaces of a routinely used treatment room in an emergency unit of a level-I hospital were treated with a surface coating (nanosilver/DCOIT-coated surface, NCS) containing nanosilver particles and another organic biocidal agent (4,5-dichloro-2-octyl-4-isothiazolin-3-one, DCOIT), whereas surfaces of another room were treated with a coating missing both the nanosilver- and DCOIT-containing ingredient and served as control. Bacterial contamination of the surfaces was examined using contact plates and liquid-based swabs daily for a total trial duration of 90 days. After incubation, total microbial counts and species were assessed. In a total of 2880 antimicrobial samples, a significant reduction of the overall bacterial load was observed in the NCS room (median: 0.31 cfu/cm2; interquartile range: 0.00-1.13) compared with the control coated surfaces (0.69 cfu/cm2; 0.06-2.00; P < 0.001). The nanosilver- and DCOIT-containing surface coating reduced the relative risk of a critical bacterial load (defined as >5 cfu/cm2) by 60% (odds ratio 0.38, P < 0.001). No significant difference in species distribution was detected between NCS and control group. Nanosilver-/DCOIT-containing surface coating has shown efficiency for sustainable reduction of bacterial load of frequently touched surfaces in a clinical setting.

Development of Device for Pressure Control System in a Freezer of Pressed-Plate Type

The process of freezing foodstuffs can be done by using a cold metal plate that is in contact with the frozen material (contact plate freezing). The magnitude of contact Force Compressive applied needs to be controlled so as not to damage the frozen material. The purpose of this study was to develop and evaluate the performance of a Force Compression control system on a contact plate freezer. The Force Compression control system was composed of a load cell mounted on a Force Compression device, connected to a set of controllers consisting of an HX711 module, ATM Mega Arduino and a computer using the Borland Delphi 7 language. The results showed that the developed system was able to control the compression process of the equipment by turning off voltage input of the motor when the specified setting point has been reached. The results of Force Compression values when the motor in off position for the setting points of 50, 100, 150, 200, 250, and 300 kg.m/s2 were 58.25, 110.25, 162.67, 213.83, 264.55, and 317.61 kg.m/s2, respectively. There was a difference that gradually increased with increasing setting point value, where the real Force Compression values when the motor off were higher than the setting point values. The relationship between real Force Compression and setting point Force Compression could be given in the form of a linear regression equation y = 1.06897x + 6.14667 with a value of R2 = 0.99, RMSE 1,53 and MAPE 11,75 %. Keywords: Arduino, Control system, Force Compression, Force Compression plate, Setting point

Bransfield Strait and South Shetland Islands sedimentary basement and upper crustal structure: An analysis of gravity and magnetic data at the northwestern area of the Antarctic Peninsula

The northwestern region of the Antarctic Peninsula is of main interest to the geosciences. Complex tectonic activity in this area is evidenced by the presence of the sinistral South Scotia ridge system and Shackleton plate contacts; As well as the opening of the Bransfield Strait leading to the formation of the Shetland Block, where the last remnant of the Phoenix convergent margin is located. Potential fields such as gravity and magnetism can be used to study crustal structure in these remote regions, where sedimentary basins are located. In this study, we utilized gravity data from the EIGEN-6C4 combined field model and magnetic data from the ADMAP2 magnetic anomaly model. We employed the Spectral decomposition of gravity anomalies to analyze sedimentary basement depth and directional derivatives of gravity and magnetic anomalies to derive structural features and magmatic activity. The gravimetric basement model was compared with previous interpretations of the acoustic basement and provides a new interpretation of basement morphology in regions that have not been studied previously in detail. The gravity/magnetic derivatives highlight evidence for ongoing magmatic activity in the Central Bransfield Basin which correlates with seismic catalogs, and crustal segmentation between King George and Gibbs Islands related to the unstable intersection of the South Scotia Ridge system and Shackleton Fracture Zone.

Studying the effect of embedded length strength of concrete and diameter of anchor on shear performance between old and new concrete

Abstract This article illustrates the specifications required to accurately design, specify, and install embedded anchor bolts between old and new concrete composite specimens for concrete repair or reinforcing of collapse concrete a research hotspot. The concrete slabs are facing a major challenge with deterioration, especially for reinforcement corrosion caused mainly by severe cycles of various chemical attacks. In this research, the impact of using contact plates between composite specimens was investigated by testing grouped specimens, thereby the models were divided into two groups, which tested under static load. The findings of a series of tests conducted to evaluate the structural behavior of shear connections (by pushout test) by including many parameters; the diameter (8, 12 and 16 mm), bounding between different compressive strength should be changed [normal concert (NC) mixes , ultra-high performance fiber concrete (UHPFC), and self-compacting mortar (SCM)]. Also, the embedded length of bolts was varied from 70, 130, to 190 mm. These parameters were studied individually in two groups. The first group was without contact plate and the second group was with contact plate. Experimental findings were obtained and reported, including the failure modes, maximum resistance, slippage capacity, and load–slip characteristic responses of the connections. Based on the obtained data, a relationship between the studied parameters was investigated. Experimental findings showed that the ultimate strength of rough surface specimens (without contact plate) was about 31% greater than that of smooth surface specimens (with contact plate), and obviously, all pushout specimens failed due to stud shank failure.

Towards the identification of the link between the contact roughness and the friction-induced vibration: Use of deep learning

To date, there is no general criterion to determine in advance the friction-induced-vibrations such as squeal, chatter, etc. Indeed, these different noises depend on the conditions of contact between the moving parts (pad-disc, etc.). Indeed, it is well known that these different noises depend on the contact conditions of the moving parts (pad-disc, etc.). These contact conditions are by nature multi-scale and depend on geometries (roughness, contact plates, system, etc.), materials, and their evolution within the contact (wear, debris, etc.). From a predictive point of view, it is then necessary to establish complex modal analysis type computations for the squeal. This method has the drawback of being useable only for an established contact configuration and is therefore not adapted to the general case. This paper attempts to generalize the determination of frequencies leading to squeal for any surface. Thus to generalize, an artificial intelligence program has been developed to predict the state of the dynamical behavior and the potential squeal frequencies. The input are surface roughness data. Supervised learning starts from a multi-scale contact computation. The scheme has an accuracy rate of 99% for near-instantaneous response times. In the end, an inverse analysis will show the influential zones in obtaining these instabilities allowing in the longer term to establish a criterion.

Electrothermomechanical and torsion-bending-stretching coupling micromirrors: Numerical and analytical modeling, parametric analysis and experimental characterization method

Considering the combined effect of electrothermomechanical coupling and torsion-bending-stretching coupling in the electrostatically driven tilting micromirror, a numerical model is developed to calculate the rotation angle and vertical displacement of the bars-plate structure over the entire operating range, and for the critical state at which an arbitrary small increment of driving voltage will make the plate contact the substrate, an analytical model is developed to judge its type and calculate the critical driving voltage, critical rotation angle and critical vertical displacement. An approximately linear relationship between the rotation angle and the vertical displacement is found and calculated. The positive, negative or non-monotonic correlation of each dimension parameter, temperature variation or bending-induced midplane stretching with each performance parameter is presented, and ways to optimize the mirror's performances by adjusting dimension parameters or by making the mirror have the second type of critical state are proposed. A nondestructive experimental method is designed for fast characterizing the fabricated mirror's performances over its entire operating range and at its critical state, and this method only needs to measure a rotation angle and a vertical displacement both induced by one driving voltage, or two rotation angles induced by two driving voltages, without a need to know the mirror's material property parameters which usually change significantly with microfabrication method and structure size, and without a need to know some dimension parameters.