No abstract

The development in the area of surface modification of polymeric synthetic membranes since 2000 is reviewed. Many patents, articles, and reviews have been written on the development in the area of surface modification of polymeric synthetic membranes subjected to RO, UF, NF, gas separation (GS), and biomedical applications, mainly since 2000, but recently more attention has been given to the modification of their surfaces to obtain desirable results. In particular, most emphasis has been given to plasma treatment, grafting of polymers on the surface, and modifying the surfaces by adding SMMs (surface‐modifying molecules). New additives are synthesized to make the polymeric membrane surfaces either to be more hydrophilic or hydrophobic, aimed at improvement in selectivity and permeability of the membranes for GS, NF, and RO. Improvement in antifouling by surface modification is also a popular topic in the membrane industries. In the last 8 years, tremendous research efforts have been made on the development of antifouling membranes. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Investment casting (IC) has benefited numerous industries as an economical means for mass producing quality near net shape metal parts with high geometric complexity and acceptable tolerances. The economic benefits of IC are limited to mass production. The high costs and long lead-time associated with the development of hard tooling for wax pattern moulding renders IC uneconomical for low-volume production. The outstanding manufacturing capabilities of rapid prototyping (RP) and rapid tooling (RT) technologies (RP&T) are exploited to provide costeffective solutions for low-volume IC runs. RP parts substitute traditional wax patterns for IC or serve as production moulds for wax injection moulding. This paper reviews the application and potential application of state-of-the-art RP&T techniques in IC. The techniques are examined by introducing their concepts, strengths and weaknesses. Related research carried out worldwide by different organisations and academic institutions are discussed. List of AbbreviationsABS Acrylonitrile-butadiene-styrene ACES Accurate clear epoxy solid AIM ACES injection moulding CAM-LEM Computer-aided manufacturing of laminated engineering materials CMB Controlled metal build-up CTE Coefficients of thermal expansion DMD Direct metal deposition DMLS Direct metal laser sintering DSPC Direct shell production casting FDM Fused deposition modelling IC Investment casting LENS Laser engineered net shaping LG Laser generating LOM Laminated object manufacturing LS Laser sintering MJS Multiphase jet solidification MMA Methyl methacrylate MM II Model Maker II PC Polycarbonate POM Precision optical manufacturing PS Polystyrene RIC Rapid investment casting RP Rapid prototyping RP&T Rapid prototyping and tooling RT Rapid tooling RSP Rapid solidification process SDM Shape deposition modelling SGC Solid ground curing SL Stereolithography SLS Selective laser sintering 3D-P 3D printing Background on investment casting (IC) and rapid prototyping (RP)Investment casting (IC), or "lost-wax" casting, is a precision casting process whereby wax patterns are converted into solid metal parts following a multi-step process [1]. IC enables economical mass-production of near net shaped metal parts containing complex geometries and features [2, 3] from a variety of metals, including difficult-to-machine or non-machinable alloys. To produce precision components, the near net shape of castings can reduce machining time and cost to bring components into specifications.

No abstract

Here we show an intriguing phenomenon in the bubble electrospinning process that the ruptured film might be stripped upwards by an electronic force to form a very thin and long plate-like strip, which might been received in the metal receiver as discontinuous backbone-like wrinkled materials, rather than smooth nano-fibers or microspheres. The processes are called the bubble electrospinning. The electronic force can be replaced by a blowing air, and the process is called as the blown bubble spinning. We demonstrate that the size and thickness of the ruptured film are the crucial parameters that are necessary to understand the various observations including beads and nanoporous materials. We identify the conditions required for a ruptured film to form discontinuous structure, and a critical width of the ruptured film to form a cylindrical fiber, above which a long and thin plate-like strip might be obtained, and a criterion for oscillatory jet diameter, which leads to bead morphology of the obtained fibers. The space of the adjacent beads depends on the fiber size. We anticipate our assay to be a starting point for more sophisticated study of the bubble electrospinning and the blown bubble spinning and for mass-production of both nanofibers and nanoscale discontinuous materials

Uncontrolled hemorrhage leads to high death risk both in military and civilian trauma. Current hemostatic agents still have various limitations and side effects. In this study, natural diatom silica obtained from diatomite and diatom culture was purified and developed for hemorrhage control. To improve the biocompatibility and hemostatic performance of diatom silica, a series of chitosan-coated diatom (CS-diatom) was developed. The composition of CS-diatom prepared was optimized by in vitro hemocompatibility and blood coagulation evaluation for that prepared with 0.5%, 1%, 3%, and 5% chitosan. The results demonstrated that the CS-diatom prepared with 1% chitosan exhibited favorable biocompatibility (hemolysis ratio < 5%, no cytotoxicity to MEFs), great fluid absorbility (24.39 ± 1.53 times the weight of liquid), and desirable hemostasis effect (351 ± 14.73 s at 5 mg/mL, 248 ± 32.42s at 10 mg/mL). Further blood coagulation mechanism study indicated that CS-diatom could provide an ideal interface to induce erythrocyte absorption and aggregation, along with activating the intrinsic coagulation pathway and thus accelerated blood coagulation. Benefitting from the multiple hemostatic performances, CS-diatom showed the shortest clotting time (98.34 ± 26.54 s) and lowest blood loss (0.31 ± 0.11 g) in rat-tail amputation model compare to diatomite and diatom as well as gauze and commercial QuikClot zeolite. The results evidenced that the CS-diatom was a safe and effective hemostatic agent and provided a new understanding of nonsynthetic mesoporous materials for hemorrhage control.

No abstract

No abstract