Polyvinyl alcohol (PVA) is an organic polymer that non-toxic, harmless to the human body, and has good biocompatibility. Polyethylene glycol (PEG) a lubricity compatibility. The unique graphite structure of carbon fibers can promote potential application carbon-fiber composites in tribology. This study explores relationship between two kinds compounds fiber cloth (CFC), specifically PVA/PEG composite coating impregnated on CFC surface. synthesized by chemical cross-linking, (PVA/PEG/CFC)...

Abstract Polyvinyl alcohol (PVA) hydrogel is considered the most promising candidate for artificial cartilage because of its good lubricity and low permeability. However, efficacy single‐network PVA hydrogels under variable loads has not yet been determined. In this study, a one‐step physical‐cross‐linking method was used to compose PVA/PEG double‐network composite hydrogels. We changed polyethylene glycol (PEG) content gel tested frictional‐wear performance different speeds. With mass...

Abstract As the wear and tear effects of artificial joints disturb patients after joint replacement, techniques new lubrication materials or methods are constantly being investigated. Hydrothermal method was adopted to produce carbon quantum dots (CDs), physically cross‐linked polyvinyl alcohol‐polyethylene glycol hydrogel (PVA‐PEG) encapsulate CDs, which evaluated as a lubricant for appraisal with their slow‐release solution. Results friction experiment showed that addition CDs changed...

One of the most common problems encountered by patients using artificial joints is high wear rate. In this study, a polyvinyl alcohol/polyethylene glycol (PVA/PEG) gel was prepared through cross‐linking reaction between alcohol (PVA) and polyethylene (PEG) solutions. This can lubricate joints, thereby lowering their coefficient friction (COF) increasing service life. Various techniques, such as Fourier transform infrared spectroscopy, X‐ray diffraction, Raman spectra, photon...

Abstract With their excellent properties, hydrogels have attracted much attention for potential application. However, it is still necessary to study the influencing factors of hydrogel preparation process and its self‐healing mechanism. In this paper, method boric acid (BA) cross‐linked poly(vinyl alcohol) (PVA)/hyaluronic (HA) appeared become studied in order explore effect pressure cross‐linking process. Associated with, PVA HA were combined, then mixture was with BA produce BA‐PVA/HA...

A monitoring method called ICM (Intelligent Coating Monitoring), which is based mainly on the intelligent coating sensors, has capability to monitor crack initiation and growth in fatigue test coupons been suggested this study. The sensor normally consisted of three layers: driving layer, sensing layer protective where necessary. Fatigue tests with for various materials demonstrate detect cracks l<300μm, corresponding increment layer's resistance at level 0.05Ω. Also, measurements correlate...

The accumulation of fatigue damage in critical structural members the aging aircrafts is an increasingly complex and continuing high priority problem. There growing evidence that (i) multiple site or element may compromise fail safety older aircrafts, (ii) significant damage, with subsequent formation cracks, occur at locations not considered original failure evaluations. Thus, there now a need for:(i) wide area scanning technology capable detecting microcrack clusters over areas shaped...

This paper presents a new model to determine the required impact toughness of petroleum drill pipe steel based upon leak-before-break fracture principle. The loss law in sour critical environment was also experimentally measured which could act as good supplement for Leak-Before-Break dominating products were current industrial ability. results showed that through above be fully realized now.

Abstract By studying the corrosion behavior of oilfield pipelines in different oxygen content and corrosive medium under simulated ambient air/air foam flooding environment, dry/wet interaction between surface interface service casing is caused by air displacement/air flooding, which greatly aggravates aerobic process. The process changed from localized to uniform with increase dry wet cycles. Pitting occurs early stages cycles, chloride concentration will accelerate initiation development pitting.

Purpose Copper-graphite (Cu/C) is a type of seal material that has been widely used in liquid rocket engines and with normal metal pairs, high wear rate under oxygen lubrication. In this study, bearing steel disks were subjected to high-temperature oxidization phosphating progress create an oxidized tricresyl film (OTCP) film, using phosphate (TCP) as the solvent. It hoped surface friction coefficient can be reduced by method. Design/methodology/approach This study aim form anti-wear on...

With the research in wind turbine wake deepening, frequency characteristics are gaining more attention. Data-driven methods usually adopted to analyze performance. In this paper, a characteristics-based clustering procedure is proposed decompose into clusters, of which frequency-domain performance and dynamic evolution process can be analyzed. The first calculates amplitudes measured velocity time-series on every measurement point space, then decomposes according using algorithm. Take...

With the rapid development of oil industry, high strength-toughness drill pipe suited to task sour environment and ultra deep wells would be considered more important. A new steel, which was designed with proper decrease C content increase Cr, Ni, Mo, Nb V alloy element, developed studied in this study. The results showed that yield strength steel had reached 150ksi impact toughness than 150J, can perfectly meet “leak-before-break” crack principle. Based on observation optical microscopy...

This paper presents the determining method of impact toughness drill pipe steel used in critical sour environment. Leak-Before-Break fracture principle was adopted to deduce requirement with different strength grades for toughness, which considered both factors, such as geometry size and curvature effect. The loss law also experimentally measured could act a good supplement principle. Statistical data revealed that this be fully realized through current industrial ability.

The complex distortion often occur when the pipe sections of HSAW are cut along axis. residual stress caused by axial and radial in cut-ring test is studied elastic mechanics theory this paper, effects on analyzed according to results section mechanical status during forming pipe. research indicates that larger displacement shows torsion shearing exist strip forming, which will result stress. It suggested shall be limited technical specification line for pipeline project, especially key project.

In this paper, a sensitivity-analysis-based wind turbine optimization strategy is introduced to improve the power output stability while reducing shaft and tower loads. Both generator torque blade pitch are controlled coordinately achieve optimization. During control process, proportionally speed tracking error, which simplifies controller structure, thus, performance can be evaluated with variables sensitivities directly. The considered in stability, bending moment moment. load parameters...