Phase diagrams and interface in inflating balloon

When a cylindrical balloon is inflated, inflation often takes place nonuniformly, inflated near one end first and followed by the growth of this part along the entire cylinder. This phenomenon is discussed from the phase‐transition perspective in terms of the Gent model, a free‐energy model that has the same structure as that of the gas–liquid transition in normal fluids. A phase diagram which describes the inflation behavior is constructed, showing the binodal and spinodal curves terminated at a critical point. The hysteresis effects are discussed based on the phase diagram. The interface between the coexisting inflated and weakly inflated regions along the cylindrical balloon is also examined, and the interfacial thickness and the interfacial energy are numerically calculated. © 2014 American Institute of Chemical Engineers AIChE J, 60: 1393–1399, 2014     

Meta-analysis of second cancer risk after radiotherapy among childhood cancer survivors

Cancer risks among childhood cancer survivors following radiotherapy have not yet been well characterised in terms of radiation dose. A meta-analysis of studies on the excess relative risk per gray (ERR) of second cancer was conducted previously; unfortunately, the small number of eligible studies restricted quantitative evaluations. To solve this problem, a statistical method to calculate ERR estimates from other estimates was developed, and a meta-analysis was conducted again. The PubMed database was searched and 26 relevant studies were identified. ERR estimates were available in 15 studies, and for the other 11 studies, the regression-based model was used to calculate ERR estimates from other estimates. The overall ERR estimate was 0.40, which was much lower than that of atomic bomb survivors exposed as young children. Heterogeneity of the risk among studies was suggested, and a further study is needed to explore the heterogeneity among studies.     

Comparison of quartz and silicon as a master mold substrate for patterned media UV-NIL replica process

Nanoimprint lithography (NIL) is a promising candidate technology to fabricate patterned media for the next generation hard disk drives (HDD). The requirement of pattern pitch for the HDD or discrete-track recording (DTR) media will be as small as from 40 to 50 nm by 2011 or 2012. However not only to create such fine pitch but also long e-beam writing time such as 1 week with conventional high resolution resist ZEP520A are critical. This paper addresses the fabrication processes to combine silicon substrate and a new chemically amplified resist (CAR) for the master molds of this NIL. The e-beam writing speed with this new CAR was achieved over 3-times faster while 50 nm fine DTR patterns were demonstrated with rotary stage e-beam writer. Furthermore, the replication with J-FIL from the master mold into quartz working mold was also demonstrated.     

Microbolometer Terahertz Focal Plane Array and Camera with Improved Sensitivity in the Sub-Terahertz Region

Journal of Infrared, Millimeter, and Terahertz Waves - A pixel in an uncooled microbolometer terahertz (THz) focal plane array (FPA) has a suspended structure above read-out integrated circuit...     

Development of Charge Sensitive Infrared Phototransistors for the Far-Infrared Wavelength

Ultra-highly-sensitive far-infrared detectors are developed for potential application to astronomy. The detectors exploit a novel mechanism called Charge Sensitive Infrared Phototransistors (CSIPs), in which an upper quantum well (QW) in GaAs/AlGaAs double QW structures is positively charged up by photo-excitation via inter-subband transition. This causes the conductance of the lower QW channel to increase. The device is effectively a phototransistor, in which the upper QW serves as a photo-sensitive gate to the source-drain channel provided by the lower QW. Resultant extraordinary high photoconductive gain makes CSIPs so sensitive as to detect single photons. CSIPs are well established in the mid-infrared ( \(\lambda \) = 12–20  \(\upmu \) m), achieving noise equivalent power around 1.9 \(\times \) 10 \(^{-19}\) W/Hz \(^{1/2}\) with a quantum efficiency of 7 %. CSIPs have been demonstrated to work in longer wavelengths up to 45  \(\upmu \) m, but the sensitivity was not as high as in the shorter wavelengths, probably due to lower quantum efficiency. Reported here is a remarkable improvement in the performance of longer wavelength CSIPs (45  \(\upmu \) m), achieved primarily by optimizing the doping concentration in the upper QW. This work indicates that longer wavelength CSIPs are promising detectors for the astronomical application.     

Coal gasification by CO2 gas bubbling in molten salt for solar/fossil energy hybridization

Coal gasification with CO₂ (the Boudouard reaction: C+CO₂=2CO, Δ_rH°=169.2 kJ/mol at 1150 K), which can be applied to a solar thermochemical process to convert concentrated solar heat into chemical energy, was conducted in the molten salt medium (eutectic mixture of Na₂CO₃ and K₂CO₃, weight ratio=1/1) to provide thermal storage. When CO₂ gas was bubbled through the molten salt, higher reaction rates were observed compared to the case without CO₂ gas bubbling (CO₂ gas was streamed over the surface of the molten salt). Thus the coke formed by coal pyrolysis was well suspended in the molten salt by CO₂ gas bubbling. When the CO₂ flow rate was increased from 15 to 60 μmol/s, the CO evolution rate was increased (15 to 26 μmol/s). However, CO₂ conversion efficiency was decreased (50 to 22%). Based on the maximum CO evolution rate (26 μmol/s), solar thermal energy from a solar farm (300×300 m²) could be converted to chemical energy at a rate of 50,000 kJ/s by the coal (23 ton as C) gasification process studied here. This assumes 50% solar heat to chemical energy conversion efficiency which can be generally obtained by the actual solar experiments.     

Functional immobilization of recombinant alkaline phosphatases bearing a glutamyl donor substrate peptide of microbial transglutaminase

Covalent and site-specific protein immobilization catalyzed by microbial transglutaminase (MTG) was investigated using recombinant Escherichia coli alkaline phosphatase (AP) tagged with a glutamyl donor substrate peptide (MLAQGS) of MTG. A polystyrene surface physically coated with beta-casein or bovine serum albumin (BSA) was employed as an MTG-specific surface displaying reactive lysine residues. MTG-mediated protein immobilization through catalytic varepsilon-(gamma-glutamyl)lysine bond formation between the peptide tag of recombinant APs and beta-casein- or BSA-coated surface was verified by the detection of AP activity on the surface. It was found that the length and the insertion position of the peptide tag did not significantly affect the efficacy of enzymatic immobilization of the recombinant APs. On the other hand, pH and ionic strength in the reaction media had crucial effects on the immobilization yields. Interestingly, the optimum pH range of MTG-mediated protein immobilization differed markedly from that for an MTG-catalyzed reaction in aqueous solution. The results suggest that the concentration of reactive species due to electrostatic interaction between the enzyme-substrate intermediate and the protein-adsorbed surface is a key factor governing MTG catalysis at a solid surface.     

Separation of oil-in-water emulsions by microbubble treatment and the effect of adding coagulant or cationic surfactant on removal efficiency

This study examined the efficiencies of microbubble (MB) treatment, MB treatment with polyaluminium chloride (PAC) as a coagulant, and MB treatment with cetyltrimethylammonium chloride (CTAC) as a cationic surfactant in the separation of emulsified oil (EO) by modified column flotation. Batch mode experiments were conducted by synthesizing emulsified palm oil (d<20 μm), and the chemical oxygen demand (COD) of the influent and effluent was measured to evaluate the treatment performance. MB treatment with PAC and MB treatment with CTAC were found to be more efficient in EO removal than the MB treatment alone. At an EO concentration of ～1,000 mg L(-1) (pH 7) and under identical treatment conditions (MB generation time: 2.5 min, flotation time: 30 min), MB treatment with PAC (50 mg L(-1)) and that with CTAC (0.5 mg L(-1)) showed equally high EO removal efficiencies of 92 and 89%, respectively. This result is of significant relevance to studies focusing on the development of economical and high-efficiency flotation systems. Furthermore, the effect of pH was investigated by varying the sample pH from 3 to 8, which showed that the EO separation efficiency of MB alone increased drastically from slightly alkaline to acidic condition.     

A cell-transverse display algorithm for regular and rectilinear 3D grid data

This paper proposes an efficient direct imaging algorithm for constructing iso-surfaces from regular and rectilinear 3D grid data in scientific and engineering visualization. The basic idea is to generate and draw polygons simultaneously by processing the cells spanned by grids in decreasing order of distance from the current viewpoint. Iso-surfaces are generated in five or six tetrahedrons into which the cells are subdivided, and are sent to a graphics device or drawn into a frame buffer on the fly. The execution order of each of the tetrahedrons is identical and is determined by the current viewpoint. Since the algorithm does not need to store intermediate polyhedral data and does not require a depth buffer memory for hidden surface removal, it is applicable to a large quantity of data on a 3D grid, such as computed tomography (CT) data. It is also particularly powerful for semi-transparent display, because transparency calculation can be reduced to image compositing operations if the polygons are drawn in order of their z-depth from the current viewpoint.