Enhanced Distillation Under Infrared Characteristic Radiation

This chapter introduces quasi-steady water vaporization under mid-infrared (IR) radiation and the IR absorption of characteristic radiation associated with the first-kind liquid-gaseous phase transition of water. When characteristic radiation in the mid-IR spectral range is applied to water surface, the strong volumetric absorption of radiation energy in the liquid-phase causes water to be nearly isothermal. In addition to volumetric absorption, surface absorption of characteristic radiation induces vaporization of water. The complete mechanism of liquid-gaseous phase-transition radiation involves the direct surface absorption/emission of infrared energy accompanied by evaporation/condensation of water. A direct consequence of excess characteristic radiation upon water surface is the induced supersaturation. This mechanism opens up a door for enhanced distillation under characteristic radiation. Blackbody-like materials such as black anodized aluminum surfaces and metal surfaces painted in black are recommended to be heated to ~250°C to serve as economical radiation sources. For isothermal water at room temperatures, ~20% supersaturation can be induced by hemispherical Blackbody radiation with temperature ~11°C higher than the water temperature. In this situation, energy extracted from the ambient for water vaporization can be as much as 80% of latent heat. With radiation-enhanced evaporation, the production cost for distilled water is significantly reduced as compared to distillation at the boiling point

Process Simulation of Steam Stripping of Bleached Palm Oil Deodorization for Removing Free Fatty Acids using DWSIM

The presence of free fatty acids (FFAs) and odoriferous components in the bleached palm oil (BPO) need to be removed to meet the specific standard quality and make the oil palatable. Because FFAs and odoriferous components is more volatile than the main oil components, they vaporize readily thus being removed from the oil product. Deodorization is the key process in industry to remove FFAs by vaporizing them using steam stripping agent such as steam under vacuum. In this work, a simulation study was adopted for the analysis of deodorization process implemented in an open-source chemical process simulator software, DWSIM. The deodorization section was modelled using absorber column unit operation in the software. The process conditions and BPO compositions fed into the deodorizer were taken from literature. The simulation showed much decrease in the FFAs content below the maximum value as standardized by the authorized association. The deodorization of BPO was analyzed by studying the column profiles such as the individual TGs, FFAs and water interstage flows in vapour and liquid phases, and the total component interstage flow for vapour and liquid phases’ profiles. From the simulation study under defined process conditions, the percentage removal of FFAs from the BPO was >99.99%

Nearly 90% Circularly-Polarized Emission in Monolayer WS₂ Single Crystals by Chemical Vapor Deposition

Monolayer transition-metal dichalcogenides (TMDCs) in the 2H-phase are semiconductors promising for opto-valleytronic and opto-spintronic applications because of their strong spin-valley coupling. Here we report detailed studies of opto-valleytronic properties of heterogeneous domains in CVD-grown monolayer WS₂ single crystals. By illuminating WS₂ with off-resonance circularly-polarized light and measuring the resulting spatially resolved circularly-polarized emission (P_circ), we find significantly large circular polarization (P_(circ) up to 60% and 45% for α- and β-domains, respectively) already at 300 K, which increases to nearly 90% in the α-domains at 80 K. Studies of spatially resolved photoluminescence (PL) spectroscopy, Raman spectroscopy, x-ray photoelectron spectroscopy (XPS), Kelvin-probe force microscopy (KPFM) and conductive atomic force microscopy (CAFM) reveal direct correlation among the PL intensity, defect densities and chemical potential, with the α-domains showing lower defect densities and a smaller work function by 0.13 eV than the β-domains. This work function difference indicates the occurrence of type-two band alignments between the α- and β-domains. We adapt a classical model to explain how electronically active defects may serve as non-radiative recombination centers, and find good agreement between experiments and the model. Scanning tunneling microscopic/spectroscopic (STM/STS) studies provide further evidences for tungsten vacancies (WVs) being the primary defects responsible for the suppressed PL and circular polarization in WS₂. These results therefore suggest a pathway to control the opto-valleytronic properties of TMDCs via defect engineering

Threshold resummation for exclusive B meson decays

We argue that double logarithmic corrections $\alpha_s\ln^2 x$ need to be resumed in perturbative QCD factorization theorem for exclusive $B$ meson decays, when the end-point region with a momentum fraction $x\to 0$ is important. These double logarithms, being of the collinear origin, are absorbed into a quark jet function, which is defined by a matrix element of a quark field attached by a Wilson line. The factorization of the jet function from the decay $B\to\gamma l\bar\nu$ is proved to all orders. Threshold resummation for the jet function leads to a universal, {\it i.e.}, process-independent, Sudakov factor, whose qualitative behavior is analyzed and found to smear the end-point singularities in heavy-to-light transition form factors.Comment: 10 pages, more details are include

The Yuan-Tseh Lee Array for Microwave Background Anisotropy

The Yuan-Tseh Lee Array for Microwave Background Anisotropy (AMiBA) is the first interferometer dedicated to studying the cosmic microwave background (CMB) radiation at 3mm wavelength. The choice of 3mm was made to minimize the contributions from foreground synchrotron radiation and Galactic dust emission. The initial configuration of seven 0.6m telescopes mounted on a 6-m hexapod platform was dedicated in October 2006 on Mauna Loa, Hawaii. Scientific operations began with the detection of a number of clusters of galaxies via the thermal Sunyaev-Zel'dovich effect. We compare our data with Subaru weak lensing data in order to study the structure of dark matter. We also compare our data with X-ray data in order to derive the Hubble constant.Comment: accepted for publication in ApJ (13 pages, 7 figures); a version with high resolution figures available at http://www.asiaa.sinica.edu.tw/~keiichi/upfiles/AMiBA7/pho_highreso.pd