Measurement of Liquid Film Thickness by a Fringe Method

A technique was developed and tested to measure the local thickness of a droplet or a liquid film on a surface of an opaque or thick single transparent plate by an interference fringe pattern that was easily formed by reflecting laser lights. Monochromatic epi-illumination through an objective lens of a conventional microscope was provided by a 5 mW or 300 mW laser and a filter to remove the noise caused by laser speckle. The incremental height difference of the liquid layer between neighboring maxima or minima of fringes was evaluated from the wavelength of the laser light and the refractive index of the liquid. Estimation error of a local inclination angle was discussed using ray tracing under parallel illumination approximation. Droplet profiles evaluated from the interferogram that were obtained by the present fringe method agreed well with those by Laser Focus Displacement Meter. Measurement was made to ensure the usefulness of the present technique. It was made clear that the contact angle of a liquid droplet could be obtained precisely and swiftly, even in small size or small contact angle, and that instantaneous three-dimensional profile of a liquid film on a bubble moving in a microchannel could be measured. The fringe method had sufficient potential to obtain more detailed information about three-dimensional characteristics of liquid film in flows such as the generation, breakdown, and growth of waves and the liquid film on a bubble at the beginning of movement.     

Tribological issues in reducing piston ring friction losses

In this paper improvement in fuel economy by reducing piston ring friction is studied and reduction of piston ring tension and the use of two-ring packages are found to be effective. However, these can be accompanied by adverse effects such as excessive wear and increasing oil consumption, and measures to overcome these problems are studied in detail.     

In situ measurement of lithium mass transfer during charging and discharging of a Ni–Sn alloy electrode

The charging (lithiation) and discharging (delithiation) of a Ni–Sn alloy electrode was examined by means of holographic interferometry and laser scanning confocal microscopy (LSCM). The developing concentration profile of Li⁺ ion during discharging (delithiation) of the Ni–Sn alloy electrode agreed reasonably well with the prediction based on transient diffusion theory, indicating that the cell configuration successfully suppressed natural convection due to the electrochemical reaction. The morphological variation of Ni–Sn alloy electrode during charge/discharge cycle could be observed very clearly by in situ LSCM. It was found that the contraction of active material during the discharge (delithiation) initiates cracks in the Ni–Sn alloy electrode.     

Improving sinterability of ceramics using hybrid microwave heating

Microwave processing, as a new method for sintering ceramics, has key advantages such as increased heating rate, uniform heating and reduced cost compared to conventional methods. It is generally accepted that microwave sintering can improve the macroscopic mechanical performances of ceramics, however, the performances of microwave-sintered ceramics on the microscopic scale are rarely investigated. In the present study, the ceramics are sintered by hybrid microwave sintering (HMS), which combines the characteristics of microwave heating and conventional heating. To evaluate the homogeneous performance of the sintered ceramics, the behaviors of thermal residual stress distribution in the microwave-sintered and conventionally sintered ceramics were investigated by X-ray diffraction technique. The thermal residual stress investigation shows microwaves can sinter ceramics in entire volume while offering improved mechanical properties. Subsequently, the distribution behaviors of pore ratio and hardness in the ceramics were investigated, respectively. The experiment results confirm that the sinterability of ceramics is homogenously improved by hybrid microwave sintering.     

Separation of PRMMC into matrix alloy and reinforcements by nozzle filtering method

The SiC_P/Al–4 mass%Cu alloy composites fabricated by a low-pressure infiltration process (LPI process) were remelted and separated by nozzle filtering method. In the separation process, the PRMMC specimen was placed in a container with a small nozzle at the bottom. The molten PRMMC was forced to flow out through the nozzle by applying a certain pressure of Ar gas. Most of the molten matrix alloy flowed out through the nozzle and the remainder in the container consisted of SiC particles and a part of the matrix alloy. The particle volume fraction of the remainder was higher than that of the original PRMMC and the remainder would work as a filter to separate SiC particles from the matrix alloy melt. When nozzle tip angle was ranged from 60° to 120°, about 80% of matrix alloy in the PRMMC was separated and few SiC particles were observed in the separated matrix alloy. The surface of recovered SiC particles became slightly roughened due to the reaction with the molten matrix during the separation process. However, this is not expected to affect their reuse.     

Dielectric properties of woven fabric glass fiber reinforced polymer-matrix composites in the THz frequency range

Electromagnetic wave transmittances of plain woven fabric glass fiber reinforced epoxy matrix composite (PW-GFRP) and eight-harness-stain fabric glass fiber reinforced polyimide matrix composite (8H-GFRP) with 1.0 mm thickness were measured in a terahertz (THz) frequency range. The transmittance values for both composites are nearly zero at a frequency of 1.0 THz. The real parts of the complex dielectric constant, ε′(ω) are 4.45 and 3.87 for PW-GFRP and 8H-GFRP, respectively, in the frequency range from 0.2 to 1.0 THz, and they are almost frequency independent. Conversely, the imaginary parts of the dielectric constant, ε′′(ω) for both composites linearly increases with increase of the frequency from 0.13 to 0.37 for PW-GFRP, and from 0.12 to 0.33 for 8H-GFRP.     

An Intrinsically Fluorescent Recognition Ligand Scaffold Based on Chaperonin Protein and Semiconductor Quantum‐Dot Conjugates

Genetic engineering of a novel protein–nanoparticle hybrid system with great potential for biosensing applications and for patterning of various types of nanoparticles is described. The hybrid system is based on a genetically modified chaperonin protein from the hyperthermophilic archaeon Sulfolobus shibatae. This chaperonin is an 18‐subunit double ring, which self‐assembles in the presence of Mg ions and ATP. Described here is a mutant chaperonin (His‐β‐loopless, HBLL) with increased access to the central cavity and His‐tags on each subunit extending into the central cavity. This mutant binds water‐soluble semiconductor quantum dots, creating a protein‐encapsulated fluorescent nanoparticle. The new bioconjugate has high affinity, in the order of strong antibody–antigen interactions, a one‐to‐one protein–nanoparticle stoichiometry, and high stability. By adding selective binding sites to the solvent‐exposed regions of the chaperonin, this protein–nanoparticle bioconjugate becomes a sensor for specific targets.     

Comparison of enteral nutrition with combined enteral and parenteral nutrition in post-pancreaticoduodenectomy patients: a pilot study

Background  

Many clinical studies have demonstrated that early postoperative enteral nutrition (EN) improved the postroperative course. Post-pancreaticoduodenectomy (PD), patients tend to suffer from postoperative nausea, abdominal distention, and diarrhoea, causing difficulty in the introduction of EN. In this pilot study, we investigated the appropriate nutritional mode post-pancreatic surgery.     

A new recovery process of carbon dioxide from alkaline carbonate solution via electrodialysis

Bipolar membrane electrodialysis is applied to CO₂ recovery from alkaline carbonate solution. CO₂ in flue gas is captured by an alkaline hydroxide absorbing solution to form an alkaline carbonate solution. The captured CO₂ is recovered from the alkaline carbonate solution via bipolar membrane electrodialysis, and the alkaline solution is regenerated simultaneously. To reduce the power requirement for CO₂ recovery, this study considers optimal design and operation. Three membrane arrangements were compared, and the results indicate the membrane arrangement comprising a bipolar membrane and cation exchange membrane is the most energy saving. With further optimization of operation conditions, the minimum power requirement for CO₂ recovery was reduced to 2.1 MJ/kg‐CO₂ (or 2.1 GJ/t‐CO₂). © 2009 American Institute of Chemical Engineers AIChE J, 2009