Accelerated wear testing with a microfabricated surface to evaluate the lubrication ability of biomolecules on polyethylene

Wear of ultrahigh‐molecular‐weight polyethylene (UHMWPE) and wear‐particle‐induced osteolysis and bone resorption are the major factors causing the failure of total joint replacements. It is feasible to improve the lubrication and reduce the wear of artificial joints. We need further understanding of the lubrication mechanism of the synovial fluid. The objective of this study is to evaluate the lubricating ability of three major components in the synovial fluid: albumin, globulin, and phospholipids. An accelerated wear testing procedure in which UHMWPE is rubbed against a microfabricated surface with controlled asperities has been developed to evaluate the lubrication behavior. An analysis of the wear particle dimensions and wear amount of the tests has provided insights for comparing their lubrication performance. It is concluded that the presence of biomolecules at the articulating interface may reduce friction. A higher concentration of a biological lubricant leads to a decrease in the wear particle width. In addition, in combination with the wear results and mechanical analysis, the roles of individual biomolecules contributing to friction and wear at the articulating interface are discussed. These results can help us to identify the role of the biomolecules in the boundary lubrication of artificial joints, and further development of lubricating additives for artificial joints may be feasible. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Effects and properties of poly(arylene ether benzonitrile)s of various molecular weights blended with sulfonated poly(ether ether ketone)

Poly(arylene ether benzonitrile) (PAEBN) was synthesized with 2,6‐dichlorobenzonitrile and biphenol. PAEBNs with various molecular weights (MWs), 1,640,000 and 185,000 g/mol, were synthesized by control of the stoichiometry of the monomers and were blended with sulfonated poly(ether ether ketone) (SPEEK). The effects of MW on the water uptake, swelling, methanol permeability, and proton conductivity of the SPEEK/PAEBN blend membranes were investigated. The molecular mobility of the SPEEK/PAEBN blends was also examined in this study. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Roll‐to‐roll UV embossing process applied for light bar‐based sub‐wavelength gratings for backlight

This study proposes a roll‐to‐roll process‐based sub‐wavelength grating, which is attached on a light bar to turn the side‐lit red/green/blue (620, 520, and 450 nm) incident rays into a uniformly and normally output white light with high illuminance from the light bar's surface. On the basis of the rigorous coupling wave analysis, the relationship between the first‐order transmission/reflection efficiency and the pitch of the gratings with different shapes was analyzed. The optimal design can effectively reduce the coupling length and enhance the white color balance for display applications.     

System supports for protocol and application adaptation in vertical handoffs

In overlay networks, the network characteristics before and after a vertical handoff would be drastically different. Consequently, in this paper, we propose an end‐to‐end based scheme to support protocol and application adaptation in vertical handoffs. First, we proposed a Vertical‐handoff Aware TCP, called VA‐TCP. VA‐TCP can identify the packet losses caused by vertical handoffs. If segments losses are due to vertical handoffs, VA‐TCP only retransmits the missing segments but does not invoke the congestion control procedure. Moreover, VA‐TCP dynamically estimates the bandwidth and round‐trip time in a new network. Based on the estimated bandwidth and round‐trip time, VA‐TCP adjusts its parameters to respond to the new network environment. Second, during a vertical handoff, applications also need to be adapted accordingly. Therefore, we design a programming interface that allows applications to be notified upon and adapt to changing network environments. To support our interface, we utilize the signal mechanism to achieve kernel‐to‐user notification. Nevertheless, signals cannot carry information. Thus, we implement the shared memory mechanism between applications and the kernel to facilitate parameters exchange. Finally, we also provide a handoff‐aware CPU scheduler so that tasks that are interested in the vertical‐handoff event are given preference over other processes to attain a prompt response for new network conditions. We have implemented a prototype system on the Linux kernel 2.6. From the experimental results, our proposed protocol and application adaptation mechanisms are shown to effectively improve the performance of TCP and applications during vertical handoffs. Copyright © 2008 John Wiley & Sons, Ltd.     

Composite hydrogeological investigation and characterisation methods applied at a nuclear power plant site in Taiwan

Drawing from the lessons learnt from the Fukushima nuclear disaster in Japan, the assessment of subsurface environmental hazard around nuclear power plants has emerged as a critical task. Consequently, aiming to better understand the possible environmental impact of radiation leaks into the groundwater, a prescreening programme was initiated in 2011 by the Taiwanese government. As part of this programme, this study conducted various borehole prospecting techniques to identify in situ hydrogeological characteristics at Chin‐Shan Nuclear Power Plant. Borehole electrical log, sonic log and temperature/conductivity log were conducted to explain the regional lithologic conditions and permeability of the formation. In conjunction with this, the interwell tracer and pumping test was carried out to simultaneously determine the hydraulic parameters. In our opinion, the implementation of such in situ end‐to‐end investigations is essential in interpreting in situ fluid and solute transport dynamics prior to programming any numerical scheme for early warning, vulnerability assessment and regular monitoring of a nuclear power plant site.     

One‐Step Fast Synthesis of Li4Ti5O12 Particles Using an Atmospheric Pressure Plasma Jet

A one‐step process to fabricate crystalline Li₄Ti₅O₁₂(LTO) particles directly from solution using an atmospheric pressure plasma jet (APPJ) is reported. This process uses Ti and Li ions‐containing salt solutions as the precursor, which is ultrasonically nebulized and then transported to the downstream of the APPJ using a carrier gas. With an extremely short contact time (<0.1 s) between the precursor droplets and the plasma jet, crystalline LTO can be fabricated in one step without additional rinse and postannealing steps. The LTO particle size can be effectively controlled using a preheater, the precursor solution composition and concentration, and the carrier gas flow rate. By properly adjusting the operating condition, particles of diameters from 100 nm to few μm with various morphologies can be obtained. When used as an electrode material, the resulting LTO powders fabricated under selected conditions show specific capacities over 100 mAh/g even at 50 C rate.     

A study on the characteristics and pervaporation performance of polyamide thin‐film composite membranes with modified polyacrylonitrile as substrate for bioethanol dehydration

To improve the pervaporation performance in separating an aqueous ethanol solution, polyamide thin‐film composite (TFC) membranes (m‐tolidine‐H‐TMC/mPAN) were prepared through the interfacial polymerization reaction between trimesoyl chloride (TMC) and 2,2'‐dimethylbenzidine hydrochloride (m‐tolidine‐H) on the surface of a modified polyacrylonitrile (mPAN) membrane. The effects of the feed ethanol concentration on the pervaporation performance and the durability of m‐tolidine‐H‐TMC/mPAN TFC membranes were investigated. To choose the optimal mPAN membrane as the TFC substrate, the effect of hydrolysis time on the chemical properties and separation performance of an mPAN substrate was also studied. An appropriate hydrolysis time of 15 min was chosen to obtain the mPAN substrate due to the corresponding high permeation flux. The m‐tolidine‐H‐TMC/mPAN TFC membrane exhibited a high pervaporation performance for ethanol dehydration. A positron annihilation lifetime spectroscopy experiment was used to estimate the mean free‐volume radius of the m‐tolidine‐H‐TMC polyamide selective layer, which lay between the radii of the water and ethanol molecules. © 2013 Society of Chemical Industry