Removal Force Research Articles

Development of a Training Simulator for Caregivers' Toothbrushing Skill Using Virtual Reality

Oral care is key to maintaining overall health. Elderly people and people with disabilities who require nursing care can have difficulty in brushing their teeth effectively and may require the assistance of a caregiver. However, to date, an effective method for teaching toothbrushing skills to caregivers and a training system that can be implemented in a non-in-person setting have not been established. Therefore, in this study, we developed a training simulator that enables skill acquisition while learning ideal brushing motion and force information from an arbitrary viewpoint in a virtual reality (VR) space. In this simulator, the position and orientation of the toothbrush as measured by six infrared cameras and the brushing force as measured by a small 6-axis force sensor are displayed in a VR space using computer graphics to match the visual information in the VR space with hand-force information in real space. The experiment was conducted in 10 healthy adults with no specialized skills or knowledge regarding oral care. They were trained to brush the cervical and distal parts of the maxillary central incisors while learning the ideal brushing motion shown by the computer graphics and the appropriate range of brushing force. Afterwards, skills were quantified in terms of brushing motion, brushing force, and plaque removal rate, and the overall effectiveness of the training was evaluated. The results showed that in cervical part brushing, the mean error between the participants' brushing motion and the ideal brushing motion in the brushing direction improved from approximately 4.8 mm before training to 3.9 mm after training. In distal part brushing, the error improved from approximately 3.8 mm to 1.9 mm. Similarly, brushing force improved from approximately 0.8 N before training to the appropriate force of 1.5 N after training for both cervical and distal part brushing. The artificial plaque removal rate improved from 40.3% to 68.7% for cervical part brushing and from 39.5% to 63.3% for distal part brushing, indicating the effectiveness of training using the proposed system. This simulator, which can simultaneously teach both brushing motion and brushing force, is expected to be developed as a new method for teaching toothbrushing skills to caregivers.

Investigation and optimization of parameters in face milling of S50C steel under MQL system

This paper aims to investigate cutting and lubrication parameters on surface roughness, cutting force, and material removal rate in face milling of JIS S50C carbon steel under a peanut oil-assisted Minimum Quantity Lubricant system. The five 3-level cutting process parameters were considered variants, including cutting speed, feed rate, depth of cut, air pressure, and lubrication flow. The experimental design was based on Taguchi's orthogonal array L27. The Analysis of variance is used to analyze the effect of cutting parameters and lubrication conditions on the surface roughness and cutting force. In addition, both regression optimizer procedures based on regression models and the Multi-Criteria Decision Making method were successfully applied to find the optimum conditions of the cutting parameter. The results showed the advantage and disadvantages of each technique. The Multi-Objective Optimization by Ratio Analysis was used in finding the best alternative. However, these values may not be an optimum condition. Mathematically, a regression optimizer may better determine the optimal value.

Cutting Parameters Optimization in Turning Operation using Taguschi Method

The objective of this study is to optimise the cutting parameters in Turning Operation. For this objective Taguchi Method was used. S/N ratio, ANNOVA was used to investigate the cutting force components & Material removal rate (MRR). In results optimal cutting parameters were obtained and the factors affecting cutting performance were analysed. It was concluded that cutting parameters i.e. depth of cut has influence on cutting force and material removal rate.

“A geography of the soul”: The displaced and the city in the work of Aleksandar Hemon

AbstractBosnian‐American author Aleksandar Hemon is a self‐described diasporic writer interested in questions of identity, displacement, and exile. This article proposes an approach to the Hemonian displaced character based on two of the most influential conceptualisations of contemporary subjectivity: on the one hand, Rosi Braidotti's critical posthuman subject, a nomadic, multiple subject who embodies complexity, favours a dynamic notion of relationality, opposes the view of difference as inferiority, and embraces a situated and accountable perspective. On the other, Nicolas Bourriaud's radicant subject, a wanderer caught between an urge to connect with the other and the forces of dislocation and removal, between individuality and the standardisation enforced by globalisation, between exchange and imposition, between enrooting and uprooting. In Hemon, subject and city are essential constituents of an elaborate system—aimed at fostering bonding and building community—which has been damaged by forced migration and violence. The insistence with which the subject's process of becoming is grounded in an urban context invites a topopoetic reading of Hemon's fiction and nonfiction. The obsessive description of the war‐ravaged architecture of besieged Sarajevo turns home into what Maria Tumarkin calls a ‘traumascape’, a place marked by violence and loss. Meanwhile, Chicago is the non‐place that the refugee is forced to shape into a narrative space in order to build a human network and a personal infrastructure—what Hemon terms ‘a geography of the soul’. Ultimately, the phenomenological approach to the sensory experiences and material practices of the displaced person reveals how their predicament adds new meanings to urban wandering and the construction and appropriation of the city from below. The human and the urban are seen as operating in a complex network of interconnections and interdependencies, generating an ongoing state of encounter that allows Hemon and his characters to feel ‘placed’, both physically and metaphysically.

The effects of surface and particle properties on adhesion in humid environments using the enhanced centrifuge method

Particle characteristics and environmental conditions, such as humidity, impact the adhesion behavior of powders. The adhesion between silica powders and glass surfaces was studied to document the effects of the topography of the particles and the surfaces on the adhesion. The study was performed utilizing an experimental and modeling framework called the enhanced centrifuge method (ECM), which measures the complete distribution of adhesion forces between a powder and surface as a function of the size of the particles in the powder. By systematically varying the relative humidity, the ECM can be used to capture how the adhesion forces between the surface and the powder change and can offer insight into the adhesion mechanisms. In this case, changes in relative humidity caused moisture adsorption onto the particles and in the interstitial space between the particles and surfaces. The balance between: 1) adsorbed moisture screening van der Waals forces, 2) adsorbed moisture inducing capillary interactions, and 3) adsorbed moisture increasing the removal force on particles by increasing their mass, caused changes in the particle adhesion as a function of particle size.

Functional anatomy and disparity of the postcranial skeleton of African mole-rats (Bathyergidae)

The burrowing adaptations of the appendicular system of African mole-rats (Bathyergidae) have been comparatively less investigated than their cranial adaptations. Because bathyergids exhibit different digging modes (scratch-digging and chisel-tooth digging) and social systems (from solitary to highly social), they are a unique group to assess the effects of distinct biomechanical regimes and social organization on morphology. We investigated the morphological diversity and intraspecific variation of the appendicular system of a large dataset of mole-rats (n = 244) including seven species and all six bathyergid genera. Seventeen morpho-functional indices from stylopodial (femur, humerus) and zeugopodial (ulna, tibia-fibula) elements were analyzed with multivariate analysis. We hypothesized that scratch-diggers (i.e., Bathyergus) would exhibit a more specialized skeletal phenotype favoring powerful forelimb digging as compared to the chisel-tooth diggers, and that among chisel-tooth diggers, the social taxa will exhibit decreased limb bone specializations as compared to solitary taxa due to colony members sharing the costs of digging. Our results show that most bathyergids have highly specialized fossorial traits, although such specializations were not more developed in Bathyergus (or solitary species), as predicted. Most chisel tooth-diggers are equally, or more specialized than scratch-diggers. Heterocephalus glaber contrasted significantly from other bathyergids, presenting a surprisingly less specialized fossorial morphology. Our data suggests that despite our expectations, chisel-tooth diggers have a suite of appendicular adaptations that have allowed them to maximize different aspects of burrowing, including shoulder and neck support for forward force production, transport and removal of soils out of the burrow, and bidirectional locomotion. It is probably that both postcranial and cranial adaptations in bathyergids have played an important role in the successful colonization of a wide range of habitats and soil conditions within their present distribution.

Redox-Mediated Electrodialysis for Resource Recovery and Energy-Efficient Desalination

In the chemical and biochemical manufacturing industry, separation processes are amongst the most energy-demanding processes. Electrochemical separations have been growing in interest as promising candidates for both downstream processing for resource recovery and producing clean water due to their energy-efficient, environmentally benign, and modular features.1 Leveraging a sustainable redox reaction, we developed a redox-mediated electrodialysis system for energy-efficient desalination coupled with resource recovery of valuable resources such as lithium, and even biomolecules.2, 3 Our proposed redox-mediated electrodialysis system utilizes a reversible redox reaction as a driving force of salt removal at a much lower voltage than a water-splitting reaction (>1.2 V). As the redox materials are reduced or oxidized, all charged species migrate across the membranes to balance the charge in the electrolyte compartment. As the redox materials circulate in the cathode and anode compartments, they sustainably regenerated without additional regeneration steps, one of the major bottlenecks for industrializing the electrosorption system. We demonstrated the redox-mediated electrochemical system for resource recoveries such as simultaneous lithium recovery from brine3 and valorization of whey proteins and lactose from whey waste.2 Especially for the valorization of whey waste, our system treated 99% of salt from the whey solution within a single step and recovered > 98% of various whey proteins (e.g., valuable protein contents such as beta-lactoglobulin, alpha-lactalbumin, and lactose). The preliminary techno-economic analysis confirmed the economic potential of redox-mediated ED with 51−73% lower energy consumption compared to conventional ED. Overall. we envision the system can become a breakthrough in tackling the environmental challenges coupled with the limited resources. Kim, N.; Jeon, J.; Chen, R.; Su, X., Electrochemical separation of organic acids and proteins for food and biomanufacturing. Chemical Engineering Research and Design 2022, 178, 267-288.Kim, N.; Jeon, J.; Elbert, J.; Kim, C.; Su, X., Redox-mediated electrochemical desalination for waste valorization in dairy production. Chemical Engineering Journal 2022, 428, 131082.Kim, N.; Su, X.; Kim, C., Electrochemical lithium recovery system through the simultaneous lithium enrichment via sustainable redox reaction. Chemical Engineering Journal 2021, 420, 127715.

Evaluation of Removal Force in Prosthetic Components of Morse Taper Dental Implants.

The longevity of prosthetic rehabilitation is determined by the stability of the implant and abutment interfaces. True morse taper connections on dental restorations have been effective, however activation force still empirical. This work compared the activation strength and internal contact of Morse taper system according to the removal force. Eighty sets, composed of implants and prosthetic abutments, were evaluated with different internal contact areas; 15.12mm2 (G3.3) and 21.25mm2 (G4.3). The specimens were activated at 0° and 30°, with loads of 10, 20, 40 and 60N. The specimens were submitted to tensile test and the data to ANOVA and Tukey's tests (α=0.05). Representative specimens were examined under SEM. Removal force of G3.3 (2.15±1.33MPa) did not differed to G4.3 (1.99±1.03MPa). The activation at 0º (2.95±0.98MPa) statistically differed to 30º (1.19±0.54MPa). The 60N load was statistically superior for G3.3 and there was no statistical difference between 20N to 60N in G4.3. The values of 10N at 30o and 20N at the long axis of the morse taper implant, independent of the frictional contact area showed the best settlement.

Tines made of degradable materials with decreasing removal forces: An option to facilitate passive-fixation leads extraction from the very beginning?

Risks during transvenous lead extraction (TLE) are serious, especially for passive fixation (PFix) leads. We attempted to fabricate a PFix lead using degradable tines to facilitate lead removal. Dried polymer mixture with poly (d-lac tide-co-glycolicde acid) (PLGA)/Poly (l-lac tide-co-ε-caprolactone) (PLCL) were put into to a specially-made mold respectively to test the tine-making feasibility and the final formulation was determined as PLGA25-PLCL75 with mass ratio 25:75 of PLGA/PLCL. Dynamic mechanical analysis and X-ray Diffraction showed excellent physicochemical characterizations, and further tests demonstrated satisfying mechanical properties similar to traditional silicone tines. The PLGA25-PLCL75 also showed low cytotoxicity and appropriate biodegradability in vitro and in vivo. The PFix leads were tested to reassure the implantation feasibility before implantation via standard surgery operation procedure. Then the leads were implanted into dog’s endocardium. The animal study showed the degradable tines could accomplish fixation stability and were with less manual extraction forces comparing with traditional silicon fixation tines in 7-month’s observation time. Tines made of PLGA25-PLCL75 blends were almost degraded totally only few remnants observed under microscope comparing with intact silicon materials at the tine-myocardial interfaces. The PFix lead might revolutionize products because of the introduction of this degradable fixation tines that make easier removal.

Abrasive belt grinding force and its influence on surface integrity

ABSTRACT Titanium alloys have been widely used in ships, aviation, aerospace, and other industries because of their excellent material properties. In the abrasive belt grinding of titanium alloy materials, abrasive belt grinding is a kind of flexible grinding, and its cutting force and material removal are important parameters that characterize the machining process. Powerful belt grinding can realize the removal of large materials, but ensuring its surface integrity is also crucial to the comprehensive material properties of titanium alloy materials. This paper studies the grinding amount: the effect of feed rate, linear speed, and initial grinding pressure on the grinding force, and the influence of the grinding force on the law of material removal and surface integrity. By studying the relevant parameters of abrasive belt grinding consumption, revealing its changing law, determining the best grinding range, and obtaining the best powerful grinding parameters. It is concluded that the maximum grinding force can be achieved when the maximum initial grinding pressure is 12N and the smaller feed speed is 200 mm/min and the medium-high line speed is 15.6 m/s while achieving a large margin of material removal and ensuring better surface integrity.

P23. Inline axial forces associated with implantation of ALIF interbody devices with integrated supplemental fixation

<h3>BACKGROUND CONTEXT</h3> Anterior lumbar interbody fusion (ALIF) allows for an optimal sized interboy device while providing correction for lumbar lordosis, restoration of disc height and indirect decompression. Spinal interbody devices with integrated fixation through blades, screws or other supplemental anchoring components mitigate the need for supplemental instrumentation, thus reducing OR time and preserving the stability of the functional spinal unit. Unfortunately, interbody devices have failed at the bone implant interface resulting in complications including implant migration and expulsion. Gaining a better understanding of the biomechanics associated with interbody placement may help to prevent these complications in the future. The aim of present study is to determine the magnitude and effect of axial forces during the deployment of an interbody device with supplemental integrated fixation. <h3>PURPOSE</h3> To understand the axial loading imparted to the functional spinal unit during lumbar interbody fusion surgery. <h3>STUDY DESIGN/SETTING</h3> Biomechanical axial load mesaurement in cadaveric functional spinal units during lumbar disc preparation and spinal interbody device implant procedures. <h3>METHODS</h3> Cadaveric functional spinal units, levels L2-L3, L3-L4, L4-L5, and L5-S1, were decorticated to the osteoligamentous structures. Posterior elements were removed to allow for MicroCT imaging of each specimen at a voxel size of 27 micron before and after instrumentation. A custom test fixture was used to apply 50N compressive force to stabilize the specimen and also record inline axial forces associated with the deployment of anchor plates during instrumentation procedures. A Chatillon DFS II force gauge was used to record axial forces during implantation of ENZA 1.0 and ENZA 2.0 interbody devices. Axial forces resulting from implant trialing, device insertion and anchor deployment were recorded. MicroCT scans were repeated to allow for quantification of damage to bony structures as a result of implantation procedures. <h3>RESULTS</h3> L2-L3 and L3-L4 force outputs are similar for both insertion, 218.82 N, 219.89 N, and deployment forces, 34.58 N, 44.88 N respectively. Insertion forces throughout all spinal levels were larger than both deployment and removal forces. Insertion forces were larger in the proximal levels, 218.82 N, 219.89 N, when compared to the distal levels, 178.96 N, 113.76 N. However, deployment force was larger in the distal levels, 99.03 N, 77.76 N, when compared to proximal 34.58 N, 44.88 N. <h3>CONCLUSIONS</h3> As evidence mounts for the cost-effectiveness of standalone cages with integrated supplemental fixation, it is imperative that design requirements of these devices continue to improve. Previous studies have shown that the vertebral endplate is susceptible to fracture under compressive loading, with the weakest area of the vertebrae being the center region. In 2001, Hasegawa et al showed a cylindrical-shaped implant caused endplate fracture between 510N and 1335N and that implant size is inversely related to the force required to cause fracture. Endplate fracture is difficult to detect with standard imaging modalities and leaves the patient vulnerable to implant subsidence and reduces segmental stability as a result of changes in load transfer. Furthermore, endplate failure may be a contributor to low back pain, further reducing the chance of a successful outcome. Our study showed interbody devices with integrated fixation plates could safely be inserted and deployed in the disc space without causing endplate fracture. The implant-endplate interface should be investigated in greater detail to allow for design of standalone interbody devices which do not cause unintended distraction or worse, damage to the vertebrae. <h3>FDA DEVICE/DRUG STATUS</h3> ENZA Lumbar Interbody Fusion Device (Approved for this indication).

Lateral force removal of fungal spores to demonstrate how surface properties affect fungal spore retention.

Microbial biofouling on polymer surfaces can lead to their biodeterioration. This may result in deterioration of the surface, leading to cracking and fracturing. Fungal spores from Aspergillus niger 1957, Aspergillus niger 1988 and Aureobasidium pullulans were tested to determine their strength of attachment on three surfaces, p(γ-MPS-co-MMA), p(γ-MPS-co-LMA) and spin-coated poly(methyl methacrylate) (PMMAsc), using lateral force measurements. The results demonstrate that A. niger 1957 and A. niger 1988 spores were most easily removed from the p(γ-MPS-co-MMA) surface, which was the surface with the highest Ra value. The A. niger 1957 and A. pullulans spores were most difficult to remove from the PMMAsc surface, which was the hardest surface. A. niger 1988 spores were the most difficult to remove from p(γ-MPS-co-LMA), the most hydrophobic surface. The results with A. pullulans were difficult to elucidate since the spores bound to all three surfaces and were removed with similar rates of force. The lateral force results demonstrate that spore attachment to a surface is a multi-factorial process, and independent surface and microbial factors influence spore binding. Thus, each environmental scenario needs to be considered on an individual basis, since a solution to one biofouling issue will probably not translate across to other systems. This article is part of the theme issue 'Nanocracks in nature and industry'.

Determination of the Suitability of the Newly Breed Güz Gülü Grape Cultivar for Cold Storage

In grape production, in order to maintain the competitive power in the domestic and foreign markets and to meet the market needs, it is necessary to have the product in a wide period of time. Especially late and high quality table grape varieties that are suitable for cold storage are needed. In the study, the suitability of Güz gülü grape variety for cold storage was investigated. The study was carried out during the harvest period of 2018 and 2019. The clusters were placed in bags weighing 5 kg and dual releasing SO2 pads with a dose of 0.9 g kg-1 of sulphur dioxide were placed in the bag. Müşküle variety was used as a control. After the applications, the grapes were stored for 90 days at 0-1 °C and 90±5% relative humidity. In order to determine the fruit quality characteristics of the samples at 15-day intervals throughout the storage period; weight loss, total soluble solids, titration acidity, maturity index, berry firmness, the removal force of the berries, cluster rachis color, decay rate, berry cracking rate and sensory analysis values were determined. It has been determined that Güz Gülü grape variety is not suitable for cold storage in Tekirdağ location due to the cracking of the skin. It was determined that the experiment should be done in locations with higher day and night temperature difference, better sun exposure and continental climate. In addition, it is recommended to apply calcium or other support components to increase the resistance of berry skin against cracking.

Revealing the effect of anion exchange resin conditioning on the pH and natural organic matter model compounds removal mechanisms

Natural organic matter (NOM) negatively affects water quality and can cause serious issues during water treatment processes. Anion exchange resins (AER) have already proven their effectiveness to remove a major part of this NOM. However, due to its complexity, understanding and improving NOM removal remains challenging. This study aimed to provide in-depth insights in NOM removal with macroporous styrenic weak (WBA), strong (SBA) and combined weak/strong basic AER. Batch experiments were performed with resins in two industrially relevant counter ion forms: OH- and free base form for SBA and WBA resins respectively, using NaOH conditioning, and Cl- form resins using NaCl and HCl conditioning for SBA and WBA resins respectively. Synthetic water containing model compounds for different NOM fractions was used, focussing on the biopolymer fraction which is typically poorly removed by classical ion exchange processes and is a known disinfection by-product precursor in drinking water. The applied resin conditioning procedure influenced the equilibrium pH and consequently NOM removal efficiency and mechanisms. When ion exchange is the dominant driving force for NOM removal, the Cl- form proved to be most efficient. For uncharged NOM containing hydroxyl groups, SBA resins in the OH- form are preferable due to H-bonding. Adsorption of aromatic NOM through π-π interactions with the polystyrene backbone was not affected by the resin conditioning. This work clearly demonstrates that not only the AER type, but also the conditioning procedure and the corresponding counter ion form play a key role in the design of successful NOM removal processes.

Determination of Optimum Machining Parameters for Face Milling Process of Ti6A14V Metal Matrix Composite.

This paper shows the novel approach of Taguchi-Based Grey Relational Analysis of Ti6Al4V Machining parameter. Ti6Al4V metal matrix composite has been fabricated using the powder metallurgy route. Here, all the components of TI6Al4V machining forces, including longitudinal force (Fx), radial force (Fy), tangential force (Fz), surface roughness and material removal rate (MRR) are measured during the facing operation. The effect of three process parameters, cutting speed, tool feed and cutting depth, is being studied on the matching responses. Orthogonal design of experiment (Taguchi L9) has been adopted to execute the process parameters in each level. To validate the process output parameters, the Grey Relational Analysis (GRA) optimization approach was applied. The percentage contribution of machining parameters to the parameter of response performance was interpreted through variance analysis (ANOVA). Through the GRA process, the emphasis was on the fact that for TI6Al4V metal matrix composite among all machining parameters, tool feed serves as the highest contribution to the output responses accompanied by the cutting depth with the cutting speed in addition. From optimal testing, it is found that for minimization of machining forces, maximization of MRR and minimization of Ra, the best combinations of input parameters are the 2nd stage of cutting speed (175 m/min), the 3rd stage of feed (0.25 mm/edge) as well as the 2nd stage of cutting depth (1.2 mm). It is also found that hardness of Ti6Al4V MMC is 59.4 HRA and composition of that material remain the same after milling operation.

Precision-improving manufacturing produces ordered ultra-fine grained surface layer of tungsten heavy alloy through ultrasonic elliptical vibration cutting

High-precision and ultra-fine grained surface of tungsten heavy alloy exhibits superior service performance that is useful for many applications and shows promises for use as key parts in nuclear protection and precision instruments. The present study concentrated on a kind of precision-improving ultrasonic elliptic vibration cutting approaches, which fabricated nanometer-level surface roughness, inhibited subsurface damages evolution, and formed continuous ultra-fine grained layer microstructure. The surface morphologies have been characterized by ultra-depth three dimensional microscope and white light interferometer. Excellent machined surface quality was achieved under ultrasonic elliptic vibration cutting condition, and an ideal surface roughness of Sa = 70.7 nm was obtained. Microstructural alteration studied using EBSD technique and TEM observation confirmed the generation of ultra-fine grained structure. Surface grain size has been reduced from 50 ∼ 100 μm to 50 ∼ 300 nm without cracks and other micro-damages. Research demonstrated that surface energy accumulation and dislocations clustering induced by high-strain rate diamond tool impact provided the primary driving force of ductile-mode removal and grain recrystallization. A dislocation density-based simulation model was carried out to complement the static experimental investigations. The present work on surface formation and microstructural evolution identified that ultrasonic elliptical vibration machining has potential to deliver improved tungsten-based alloys service performance.

Machining Strategy and Experimental Study of Ultrasonic-Assisted Bidirectional Progressive Spiral Milling of Carbon Fiber Holes

Carbon fiber-reinforced composites (CFRP) are widely used in aerospace structural holes due to their superior mechanical properties. However, fiber pulling, delamination, burr and other defects often occur in the parts, which seriously affect the accuracy and service life of the products. The traditional cylindrical milling cutter is easy to lead to the exit delamination defects due to the large axial force at the bottom edge, concentrated wear at the periphery edge, and weak rigid constraint at the exit machining position. Therefore, this paper proposed a new hole machining strategy, analyzed the kinematic law of the tapered progressive spiral milling hole, studied the cutting mechanism of the four stages of the tapered spiral bidirectional milling hole, explored the material removal force state of the ultrasonic augment-assisted progressive milling hole, and established the prediction of the layered axial force of the ultrasonic progressive milling hole. Finally, combined with the material removal mechanism of ultrasonic vibration, the self-designed bidirectional progressive spiral milling cutter was used to verify the mechanism of material removal by progressive milling, in which the axial force could be effectively reduced. After 60 and 90 holes were processed, the axial force was about 18.5 and 23.3 N, respectively, the critical force of delamination could be improved, and the hole quality could be guaranteed without obvious burr and delamination phenomena.

Relationship between Atomic Force Microscopy and Centrifugation Measurements for Dust Fractions Implicated in Solar Panel Soiling.

This work tests the reliability of a simple, rapid centrifugal technique to estimate the removal force necessary to detach common airborne particles from the surface of a photovoltaic panel. Previously, we have used atomic force microscopy (AFM) to obtain the surface-particle adhesion force for different pollutant types that generally contribute to panel soiling. To overcome the limitations of AFM, the same particles were studied as a population using an ultracentrifuge. Detachment was quantified at speeds between 1000 and 10,000 rpm, both as individual particle counts and as projected surface area coverage. The force of centrifugal detachment for each particle type followed a similar trend as the adhesion force given by AFM. Organic and carbon-based materials needed higher centrifugal speeds to be removed, suggesting a stronger attachment to the surface. However, the technique also highlighted the importance of particle diameter, aggregates, and individual particle characteristics, which should be considered when predicting the probability of detachment. We have identified the relationship between AFM-derived adhesion and centrifugal detachment forces using model particle fractions of materials commonly found to soil solar panels, demonstrating the utility in using the more easily applied to centrifugal method to obtain information that can be calibrated to direct measurements of the force of particle attachment. This technique could be applied effectively in further studies on the influence of dust composition on long-term soiling and its reversibility.

Investigation on scratching force and material removal mechanism of 3D SiCf/C–SiC composites during single grain scratching

As one of the novel fiber-reinforced ceramic matrix composites, SiCf/C-SiC composites are difficult to machine materials and the material removal mechanism is not completely clear yet. Single grain scratching tests with gradual depth have been carried out to analyze the influence of fiber orientation and woven structure on the material removal mechanism and scratching force in three typical scratched surfaces defined by the fiber orientation. Results indicate that the scratching force waveform is affected by the weaving method, fibers orientation, and porosity distribution of the scratched area, resulting in periodic fluctuations. Diamond indenter causes greater damage to the surface of SiCf/C-SiC composites when scratching along transverse fibers, while leaving narrow but deep grooves on the surface when scratching along perpendicular fibers. The dominant mode of material removal of SiCf/C-SiC composites is brittle fracture, and the damage features mainly include direct fiber breakage, matrix fragmentation, fiber pullout, fiber outcropping.

Study on machinability of Ti6Al4V with coated inserts–cutting force, surface finish and material removal rate prediction using ANN

Study on machinability of Ti6Al4V with coated inserts–cutting force, surface finish and material removal rate prediction using ANN