Experimental Abrasion Study of the Evolution of Gold Morphological Criteria in Different Sediments as a Function of Time

The use of gold as a tracer element for understanding the mode of emplacement of these formations requires a good knowledge of its dynamics. To this end, we have carried out experimental studies to investigate the evolution of contour states (regular, irregular), surface states (blunt, rough), shape (elongation) and dimension (size). The study of these criteria is carried out on SEM photos of particles, taken before and after the experiment, using Aphelion image processing software. Five experiments were carried out to study the influence of sediment granulometry and water dilution on particle morphological changes. The results of these experiments show that coarse sediments (>1 mm) are largely responsible for morphological changes in gold. They cause fragmentation and/or folding of the particle edges, depending on the magnitude of the impact forces. Strong impacts due to high water dilution cause staking on the particle surface. Fine sediments (<1 mm) slow down particle evolution as they cushion impacts and particles tend to flatten rather than fragment.

Performance comparison of training algorithms for the estimation of B?hme abrasion resistance using neural networks

Natural stones used as floor and wall coverings are exposed to many different abrasive forces,so it is essential to choose suitable materials for wear resistance in terms of the life of the structure.The abrasion resistance of natural stones can be determined in the laboratory by applying the B?hme abrasion resistance(BAR)test.However,the direct analysis of BAR in the laboratory has disadvantages such as wasting time and energy,experimental errors,and health impacts.To eliminate these disadvantages,the estimation of BAR using artificial neural networks(ANN)was proposed.Different natural stone samples were collected from Türkiye,and uniaxial compressive strength(UCS),flexural strength(FS),water absorption rate(WA),unit volume weight(UW),effective porosity(n),and BAR tests were carried out.The outputs of these tests were gathered and a data set,consisting of a total of 105 data,was randomly divided into two groups:testing and training.In the current study,the success of three different training algorithms of Levenberg-Marquardt(LM),Bayesian regularization(BR),and scaled conjugate gradient(SCG)were compared for BAR prediction of natural stones.Statistical criteria such as coefficient of determination(R~2),mean square error(MSE),mean square error(RMSE),and mean absolute percentage error(MAPE),which are widely used and adopted in the literature,were used to determine predictive validity.The findings of the study indicated that ANN is a valid method for estimating the BAR value.Also,the LM algorithm(R~2=0.9999,MSE=0.0001,RMSE=0.0110,and MAPE=0.0487)in training and the BR algorithm(R~2=0.9896,MSE=0.0589,RMSE=0.2427,and MAPE=1.2327)in testing showed the best prediction performance.It has been observed that the proposed method is quite practical to implement.Using the artificial neural networks method will provide an advantage in similar laborintensive experimental studies.

Optimizing the Diameter of Plugging Balls in Deep Shale Gas Wells

Deep shale gas reserves that have been fractured typically have many relatively close perforation holes. Due to theproximity of each fracture during the formation of the fracture network, there is significant stress interference,which results in uneven fracture propagation. It is common practice to use “balls” to temporarily plug fractureopenings in order to lessen liquid intake and achieve uniform propagation in each cluster. In this study, a diameteroptimization model is introduced for these plugging balls based on a multi-cluster fracture propagationmodel and a perforation dynamic abrasion model. This approach relies on proper consideration of the multiphasenature of the considered problem and the interaction force between the involved fluid and solid phases. Accordingly,it can take into account the behavior of the gradually changing hole diameter due to proppant continuousperforation erosion. Moreover, it can provide useful information about the fluid-dynamic behavior of the consideredsystem before and after plugging. It is shown that when the diameter of the temporary plugging ball is1.2 times that of the perforation hole, the perforation holes of each cluster can be effectively blocked.

Crystalline texture evolution, control of the tribocorrosion behavior, and significant enhancement of the abrasion properties of a Ni-P nanocomposite coating enhanced by zirconia nanoparticles

This paper describes an investigation of the effect of ZrO2 nanoparticles on the abrasive properties,crystalline texture developments,and tribocorrosion behavior of Ni-P nanostructured coatings.In the investigation,Ni-P and Ni-P-ZrO2 nanostructured coatings are deposited on St52 steel via the electroless method.Transmission electron microscopy(TEM),field emission scanning electron microscopy(FE-SEM),X-ray diffraction(XRD),energy dispersive spectroscopy(EDS),cyclic-static polarization tests in 3.5wt%NaCl solution,the tribocorrosion test(by back-and-forth wear in electrochemical cell),and the microhardness test using the Vickers method were performed to characterize and analyze the deposited coatings.The results of this study showed that the addition of ZrO2 nanoparticles to the Ni-P electroless bath produced the following:a sharp increase in wear and hardness resistance,the change of the wear mechanism from sheet to adhesive mode,the reduction of pitting corrosion resistance,significant reduction in the tribocorrosion protective properties,change in the preferred orientation of the crystalline texture coating from(111)to(200),increase in the sedimentation rate during the deposit process,and a sharp increase in the thickness of the Ni-P nanostructured coatings.

BEHAVIOURS OF AUSTEN1TE UNDER IMPACT ABRASION

The role of austenite in impact-abrasion process was studied on the basis of theimpact-abrasion test results of a newly developed austenite-bainitic ferrite dual-phaseabrasion-resistant steel with high strength,high toughness and high strain-hardening ability.It is found that the morphology,distribution and mechanical stability,rather than the volumefraction,of austenite govern the impact abrasion behaviour.Only the appropriate amount offine and evenly dispersed austenite with adequate mechanical stability in high strengthmatrices,contribute effectively to the irnpact-abrasion resistance of the materials.Whilelarge quantity of coarse austenite with poor mechanical stability,especially when it acted as acontinuous matrix of the material,is extremely detrimental to impact-abrasion resistance.

Research on Prediction Model for Erosion and Abrasion of Barrel Based on LSSVM

To predict the erosion and abrasion of high bore pressure tank gun barrel, the least square support vector machine (LSSVM) algorithm was used. Based on the gun firing test data, the prediction model for barrel's erosion and abrasion was established. It was adopted to predict the wear increment of gun barrel. The results show that the prediction values given by the model coincide with the measured data better, and the model can predict the barrel's wear accurately and rapidly.

TREATMENT OF ADVERSE REACTIONS FOLLOWING FACIAL COSMETIC SURGICAL ABRASION WITH AURICULAR PELLET PRESSURE

Cutaneous surgical abrasion is a cos-metic procedure developed in recent years.The process is to remove scars or othercutaneous lesions on the face for cosmeticpurposes by a high speed abrasive grindinghead.Since the operation brings mechanicaltrauma to the skin,adverse reactions such aspain,serous exudation or edematous swell-ing often ensue.The routine remedy hasbeen administration of sedatives,analgesics,antibiotics or steroids that may take

Development and Impact-abrasion Behaviour of New Austenite-Bainite Low AHoy Steel

A new category of steel with excellent combi-nation of strength,toughness,strain-hardeningability and excellent resistance to high-stress,espec-ially to severe impact-loaded abrasion has been de-veloped with a new idea of abrasion-resistant ma-terial design.The steels have the microstructures ofaustenite film and bainitic ferrite laths in arrange-ment of extremely fine lath spacing and arechemically high-carbon low alloy ones.The effectsof austempering temperatures on microstructures,mechanical properties,wear-resistance andbehaviour of the austenite-bainite steels inimpact-abrasion system have been emphaticallystudied.

Abrasion Behaviour of Boronized Layer

1.IntroductionBoronizing can evidently increase thesurface hardness and wear resistance of me-tallic materials[1].It is simple in technique,not expensive and widely used on tools,diesand some other parts which are easy towear.However the wear mechanism andbehaviour of boronized layer are not clearwhen abraded by mixed abradants such ascoal,hard mineral etc.[2,3].Several metallic materials

Effect of TiO2 Filler Loading on Physico-Mechanical Properties and Abrasion of Jute Fabric Reinforced Epoxy Composites

Mechanical properties and abrasive wear behaviour of bi-directional jute fabric reinforced epoxy (J/Ep) with micron sized TiO2 particles at different wt% (2.5, 5, 7.5 and 10) were investigated. The tribo-potential of combined effect of TiO2 and jute fiber in epoxy (J/Ep) for enhancing the abrasion resistance has not been studied so far. Hence, the present work aims to explore the possibility of using TiO2 filler and jute fiber to reinforce the epoxy and thus open a new way to implement inexpensive reinforcements and produce new candidate tribo-material for industrial applications. Silane treated TiO2 filled J/Ep composites were prepared by hand lay-up method. Selected mechanical properties and three-body abrasive wear tests were evaluated as per ASTM standards. Results indicate an enhancement in the J/Ep composite mechanical properties due to addition of TiO2 particles up to 7.5 wt% of loading. Highest tensile and flexural properties were found at 7.5 wt% TiO2 loading. Results of abrasion tests show resistance to abrasion at 5 wt% TiO2 filled J/Ep composite. Scanning electron micrographs evidenced that the fiber and filler have fairly good bonding with matrix. Finally, this investigation confirms the applicability of TiO2 as secondary reinforcement in J/Ep composite.

Reliability of Sawai's classification for dental cervical abrasions:A pilot study

AIM To test the reliability of the Sawai’s classification for dental cervical abrasions.METHODSIntraoral photographs of 70 teeth from 23 patients with tooth abrasions were taken by the first examiner MS.The teeth were marked and the photos were maintained in a soft copy sequentially.Two other examiners FA and SC were trained in the use of the classification and any clarifications needed were provided at the beginning of the study.Each examiner was then given the soft copy of the complied photographs and was asked to classify the dental cervical abrasion according to their understanding of the Sawai’s classification.They were given sheets to write their responses for every marked tooth.All the examiners were blinded to each other’s observations which were then tested for inter-rater agreement among the three examiners.RESULTSThe 70 teeth with tooth abrasions from 23 patients were examined by 3 investigators(MS,FA and SC)to test the reliability of the Sawai’s classification system for tooth abrasion.Each examiner marked their responses in separate sheets which were blinded to each other.The kappa statistics were performed for inter-rater agreement among the three examiners.The level of agreement was evaluated according to the six-level nomenclature given by Landis and Koch.ICC and 95%CI between two examiners,i.e.,the inter-rater agreement among 1^(st) examiner(MS) and 2^(nd) examiner(FA) was 0.89.The inter-rater agreement among 1^(st) examiner(MS) and 3^(rd) examiner(SC) was 0.89.And the inter-rater agreement among 2^(nd) examiner(FA) and 3^(rd) examiner(SC) was 0.83.All the three comparisons show an almost perfect agreement between them.CONCLUSIONThere is an almost perfect agreement between multiple observers for classifying dental cervical abrasions using Sawai’s classification.Hence,this classification is reliable.

Abrasion Resistance of Cement Paste with Granulated Blast Furnace Slag and Its Relations to Microhardness and Microstructure

The abrasion resistance of cement pastes with 30 wt%,40 wt%and 50 wt%granulated blast furnace slag(GBFS),and its relations to microhardness and microstructure like hydration products and pore structure were studied.Results indicated that GBFS decreased the abrasion resistance of paste,and among the pastes with GBFS,the paste with 40 wt%GBFS showed the highest abrasion resistance.The microhardness of GBFS was lower than that of the cement,and the microhardness of the hydration products in paste with GBFS was also lower than that of the hydration products in paste without GBFS,so that the abrasion resistance of paste decreased when GBFS was incorporated.The reason for the decrease of microhardness of pastes with GBFS was that the contents of Ca(OH)_(2)in pastes with GBFS was significantly lower than that in the paste without GBFS,while large amounts of calcium aluminate hydrates and hydrotalcite-like phases(HT)in pastes with GBFS were generated.Furthermore,among the pastes with GBFS,the paste with 40 wt%GBFS showed the lowest porosity which was the main reason for its highest abrasion resistance.

THE EFFECT OF, ABRASION ON LOW STRESS MECHANICAL PROPERTIES OF FABRIC

The low stress mechanical properties of a pure wool and a wool / polyester blend twill fab-rics which were abraded at various abrasion cycles were measured using the KES-F system andthe Instron tensile machine. The surface change of fabrics before and after abrasion was stu-died by means of scanning electron microscope. With the increasing number of cycles, the re-covery behavior of the fabrics studied in tensile, shear and bending deformation decrease, theantibuckling ability lowers, the friction coefficient increases. The geometric roughness de-creases during the first step of abrasion then enhances with further abrasion. The influence ofabrasion on mechanical properties of the pure wool fabric are larger than that of blend fabric.

Study on comprehensive properties of duplex austenitic surfacing alloys for impacting abrasion

In this paper, comprehensive property crack resistance, work hardening and abrasion resistance of a series of double phases austenitic alloys(FAW) has been studied by means of SEM, TEM and type MD 10 impacting wear test machine. FAW alloys are of middle chromium and low manganese, including Fe Cr Mo C alloy,Fe Cr Mn C alloy and Fe Cr Mn Ni C alloy, that are designed for working in condition of impacting abrasion resistance hardfacing.Study results show that the work hardening mechanism of FAW alloys are mainly deformation high dislocation density and dynamic carbide aging, the form of wearing is plastic chisel cutting. Adjusting the amount of carbon, nickel, manganese and other elements in austenitic phase area, the FAW alloy could fit different engineering conditions of high impacting, high temperature and so on.

An Abrasion Resistant TPU/SH-SiO_(2) Superhydrophobic Coating for Anti-Icing and Anti-Corrosion Applications

As a passive anti-icing strategy,properly designed superhydrophobic coatings can demonstrate outstanding performances.However,common preparation strategies for superhydrophobic coatings often lead to environmental pollution,high energy-consumption,high-cost and other undesirable issues.Besides,the durability of superhydrophobic coating also plagues its commercial application.In this paper,we introduced a facile and environment-friendly technique for fabricating abrasion-resistant superhydrophobic surfaces using thermoplastic polyurethane(TPU)and modified SiO_(2)particles(SH-SiO_(2)).Both materials are non-toxicity,low-cost,and commercial available.Our methodology has the following advantages:use of minimal amounts of formulation,take the most streamlined technical route,and no waste material.These advantages make it attractive for industrial applications,and its usage sustainability can be promised.In this study,the mechanical stability of the superhydrophobic surface was evaluated by linear wear test.It is found that the excellent wear resistance of the superhydrophobic coating benefits from the characteristics of raw materials,the preparation strategy,and the special structure.In anti-icing properties test,the TPU/SH-SiO_(2)coating exhibits the repellency to the cold droplets and the ability to extend the freezing time.The electrochemical corrosion measurement shows that the asprepared superhydrophobic surface has excellent corrosion resistance that can provide effective protection for the bare Q235 substrates.These results indicate that the TPU/SH-SiO_(2)coating possesses good abrasion resistance and has great potential in anti-corrosion and anti-icing applications.

Study on Abrasion Resistance Anisotropy of Natural Diamond Crystals

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Study on Abrasion Resistance of Modified Polypropylene Fiber Reinforced Cement

Modified polypropylene fiber reinforced cement compos-ites were investigated in their abrasion resistance andsurface morphology. The test results showed the addingof fiber could noticeably improve the abrasion resistanceof composite. The bonding and friction of fibers/cementwere the main contribution to abrasion resistance im-provement, which resulted from the surface morphologyobservation.

Mechanism of C_(4)AF Content and Heat-curing Process on the Abrasion Resistance of High Ferrite Cement

Cement used in severe maritime environments must be attached with exceptional properties such as high sulfate resistance and abrasion strength.A sulfate resistant material typically used in marine engineering is high ferrite cement,which has been utilized in sulfate-rich environments.This study aims at exploring the effect of C_(4)AF and heat-curing on the abrasion resistance of high ferrite cement(HFC,C_(4)AF:14%-22%)in order to have a comprehensive understanding of this mechanism and promote the application of HFC in marine engineering.A new invention was designed for the abrasion resistance device by considering the sea-wave abrasion and seawater erosion in laboratory.The compressive strength and abrasion resistance of HFC were measured.Additionally,advanced analytical methods were used to explore the abrasion resistance mechanism of HFC,including X-ray fluorescence(XRF),X-ray diffraction(XRD),and thermogravimetric(TG)analyses,as well as mercury intrusion porosimetry(MIP).The results showed that HFC had the best abrasion resistance under appropriate heat-curing system that the curing temperature was 50℃and the hosting time was 4 hours,compared with PI(Portland cement)and LHC(low heat cement),meanwhile the abrasion resistance of HFC had a 62.4%increase when C_(4)AF content is increased from 14%to 22%.It can be ascribed that the content of portlandite is decreased due to the increase of C_(4)AF,which can reduce the portlandite assembled in ITZ(interfacial transition zone).It can also be ascribed that the DEF(delayed ettringite formation)is successfully avoided in HFC and the hydration degree of HFC can continue to be boosted under appropriate heat-curing system.

Abrasion Resistance Comparison between Rotor and Ring Spun Yarn

On the base of literature review and the analysis of yarn properties, yarn structure and some other facts, the abrasion resistance of both rotor spun yarn and ring spun yarns are discussed. The results show that with the same raw material and twist, the rotor spun yarn has lower abrasion resistance than that of ring spun yarn, because of the higher twist employed, the abrasion resistance of rotor spun yarn is higher than that of ring spun yarn.

Coastal Abrasion and Accretion Studies of West Sumatera Province in Period 2003-2016

West Sumatera province has 19 cities and regencies where 6 of them often experience abrasion and accretion disaster,because it is a coastal area directly adjacent to the Indian Ocean.This study aims to examine the characteristics of abrasion and accretion disasters along the coast of West Sumatera Province from 2003 to 2016.By knowing the characteristics of abrasion and accretion from 2003 and 2016,it will be known which beaches are experiencing abrasion or accretion.This research is qualitative and quantitative descriptive research with GIS(Geographic Information System)analysis method to get characteristic of abrasion and accretion disaster in coastal area of West Sumatera.There has been a disaster of abrasion and accretion in 32 points spread across 6 districts and cities,namely West Pasaman District,Agam Regency,Padang Pariaman District,Pariaman City,Padang City and Padang Pariaman District,an abrasion disaster in the coastal area of West Sumatera Province of 732.69 Ha and 55.4 Ha of acres.This proves that the abrasion debacle causes the decrease of land in West Sumatera Province which is big enough that is average 56.3 Ha/year,while the addition of land is only 4.26 Ha/year.The farthest abrasion disasters are located in South Pesisir Regency,which is 45.70 m or 3.52 m/year on average.While the farthest accretion is in the South Pesisir Regency,and is as far as 36.91 m or an average of 2.84 m/year.