A research into thermal field in fluid-saturated porous media

Until now, the theory, methodology of investigations, and interpretation of thermometry data have been most completely developed for single-phase (oil, water, or gas) flows in formations. However, multiphase (oil+gas, oil+water, and oil+water+gas) flows in formations are more common in practice. This is primarily typical for fields featuring a high value of gas factor and saturation pressure, as well as for cases of formation tests at low values of bottom-hole pressure. Analysis of actual thermograms under these conditions has shown that the earlier-developed techniques for the cases of single-phase flows in the formation and the well cannot be applied here.This paper presents research data on the influence of the adiabatic and Joule-Thomson effects and the heat of fluid degassing on temperature field in porous medium.     

The effect of crystalline morphology of poly (butylene terephthalate) phases on toughening of poly(butylene terephthalate)/epoxy blends

In an effort to investigate the effect of the crystalline morphology of a poly(butylene terephthalate) (PBT) phase on the toughening of PBT/epoxy blends, the blends, having different degrees of perfectness of the PBT crystalline phase, were prepared by blending PBT and epoxy at various temperatures ranging from 200 to 240 °C. As the blending temperature decreases, the degree of perfectness of the PBT crystalline phase increases as a result of the increase of crystal growth rate. For PBT/epoxy blends, the change in crystalline morphology induced by processing may be the most important cause for the dependency of the fracture energy on blending temperatures. It has been found that PBT phases with a well-developed Maltese cross are most effective for epoxy toughening. This dependency reveals the occurrence of a phase transformation toughening mechanism. Also, the higher relative enhancement of fracture energy of a higher molecular weight epoxy system is further indirect evidence for a phase transformation toughening mechanism. Some other toughening mechanisms observed from the fracture surfaces, such as crack bifurcation, crack bridging, and ductile fracture of PBT phases, have been found to also be affected by the blending temperatures.     

Effects of mixing temperatures on the morphology and toughness of epoxy/polyamide blends

A new mixing process was explored to increase further the fracture toughness and to investigate the toughening mechanisms of epoxy/nylon blend. In this process, without mechanical mixing, the mixtures of epoxy and premade nylon 6 powder were heated without the curing agent to specific temperatures, referred to as the “mixing temperature.” For epoxy/nylon blends, at sufficiently high temperatures, a semi‐interpenetrating network‐like structure can be developed at the interphase via the reaction between the amine end group and the epoxide group. The depth of interphase and the extent of reaction depends on the mixing temperature. The strong dependency of the fracture energy on mixing temperature reveals the positive effect of the newly developed structure at the interphase. The increase of fracture toughness is possibly due to the enhanced crack fingering bifurcation/deflection mechanism resulting from the lamellae developed in the interphase and the enhanced plastic deformation of epoxy as a result of preyielding of the interphase. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1055–1063, 1999     

Recognizing interleaved and concurrent activities using qualitative and quantitative temporal relationships

The majority of approaches to activity recognition in sensor environments are either based on manually constructed rules for recognizing activities or lack the ability to incorporate complex temporal dependencies. Furthermore, in many cases, the rather unrealistic assumption is made that the subject carries out only one activity at a time. In this paper, we describe the use of Markov logic as a declarative framework for recognizing interleaved and concurrent activities incorporating both input from pervasive lightweight sensor technology and common-sense background knowledge. In particular, we assess its ability to learn statistical-temporal models from training data and to combine these models with background knowledge to improve the overall recognition accuracy. We also show the viability and the benefit of exploiting both qualitative and quantitative temporal relationships like the duration of the activities and their temporal order. To this end, we propose two Markov logic formulations for inferring the foreground activity as well as each activities’ start and end times. We evaluate the approach on an established dataset where it outperforms state-of-the-art algorithms for activity recognition.     

Phosphorescence color tuning of oxadiazole-based iridium(III) complexes for organic light emitting diode

The new heteroleptic iridium complexes bearing 2-(5-phenyl-1,3,4-oxadiazol-2-yl)phenolate (ODZ), were synthesized and characterized for application to organic light-emitting diodes (OLEDs). As main ligands (C^N), the anions of 2-phenylpyridine (ppy), 2-phenylquinoline (pq) and 2-(2,4-difluorophenyl)pyridine (F2-ppy) were chelated to the iridium center and 2-(5-phenyl-1,3,4-oxadiazol-2-yl)phenolate (ODZ) was introduced as an ancillary ligand for luminescence modulation of their iridium complexes. We expected that the relative energy levels of the main and ancillary ligands in the complexes could lead to emission color tuning and luminous efficiency improvement by possible inter-ligand energy transfer (ILET). The photoabsorption, photoluminescence and electroluminescence of the complexes were studied. Ir(F2-ppy)2(ODZ), Ir(ppy)2(ODZ) and Ir(pq)2(ODZ) exhibited the photoluminescence maxima between 505-610 nm at room temperature in CH2Cl2, depending on both main and ancillary ligands. The longer pi conjugation in the cyclometallating pq ligands leads to the bathochromic shift in luminescence of their iridium complexes. The electroluminescent properties of the complexes were influenced by ILET.     

Scaffolds for bone tissue engineering fabricated from two different materials by the rapid prototyping technique: PCL versus PLGA

Three dimensional tissue engineered scaffolds for the treatment of critical defect have been usually fabricated by salt leaching or gas forming technique. However, it is not easy for cells to penetrate the scaffolds due to the poor interconnectivity of pores. To overcome these current limitations we utilized a rapid prototyping (RP) technique for fabricating tissue engineered scaffolds to treat critical defects. The RP technique resulted in the uniform distribution and systematic connection of pores, which enabled cells to penetrate the scaffold. Two kinds of materials were used. They were poly(ε-caprolactone) (PCL) and poly(d, l-lactic-glycolic acid) (PLGA), where PCL is known to have longer degradation time than PLGA. In vitro tests supported the biocompatibility of the scaffolds. A 12-week animal study involving various examinations of rabbit tibias such as micro-CT and staining showed that both PCL and PLGA resulted in successful bone regeneration. As expected, PLGA degraded faster than PCL, and consequently the tissues generated in the PLGA group were less dense than those in the PCL group. We concluded that slower degradation is preferable in bone tissue engineering, especially when treating critical defects, as mechanical support is needed until full regeneration has occurred.     

Effect of Mn precursors on benzene oxidation with ozone over MnOx/MCM-41 at low temperature

Low temperature benzene oxidation in the presence of ozone on MnOx/MCM-41 catalysts has been studied. MnOx/MCM-41 catalysts were prepared from two different precursors, Mn(NO3)2 and Mn(CH3COO)2, and these samples were characterized by N2 sorption, X-ray diffraction, X-ray photoelectron spectroscopy and temperature programmed reduction. The characterization results showed that the MnOx/MCM-41 prepared from Mn(CH3COO)2 had higher oxygen mobility and dispersion than the MnOx/MCM-41 from Mn(NO3)2. As a result, the MnOx/MCM-41 obtained from Mn(CH3COO)2 showed higher catalytic activity for the oxidation of benzene using ozone; however, without ozone, the catalytic activity was negligible.     

Synergistic effect of Korean red ginseng extract and GABA mixture on the IgE production in mice via Th1/Th2 cell balance

Food Science and Biotechnology - It has been recently reported that the immune system has been linked to the nervous system. This study was conducted to investigate the effect of administration of...