The Effect of Thermal Radiation on Nanofluid Cooled Microchannels

This article studies thermal analysis of single phase laminar flow nanofluid cooled rectangular microchannel heat sink (MCHS) subject to the uniform wall temperature condition. The solutions for velocity and temperature distributions are obtained from both high-aspect-ratio and low-aspect-ratio microchannels. The practical criterion for the validity of the model are used to express the cases which are assumed to produce inaccuracy in heat transfer prediction, and the participating area of base and tip plates of microchannel in radiation exchange has been defined. Radiation effects of ultra fine particles incorporated in a base coolant fluid, in heat transfer enhancement of nanofluid cooled MCHS are considered, and effects of near field thermal radiation on total heat transfer of micro heat sinks are also investigated.     

Guided Molecular Assembly on a Locally Reactive 2D Material

Atomically precise engineering of the position of molecular adsorbates on surfaces of 2D materials is key to their development in applications ranging from catalysis to single‐molecule spintronics. Here, stable room‐temperature templating of individual molecules with localized electronic states on the surface of a locally reactive 2D material, silicene grown on ZrB₂, is demonstrated. Using a combination of scanning tunneling microscopy and density functional theory, it is shown that the binding of iron phthalocyanine (FePc) molecules is mediated via the strong chemisorption of the central Fe atom to the sp³‐like dangling bond of Si atoms in the linear silicene domain boundaries. Since the planar Pc ligand couples to the Fe atom mostly through the in‐plane d orbitals, localized electronic states resembling those of the free molecule can be resolved. Furthermore, rotation of the molecule is restrained because of charge rearrangement induced by the bonding. These results highlight how nanoscale changes can induce reactivity in 2D materials, which can provide unique surface interactions for enabling novel forms of guided molecular assembly.     

Human T-cell leukemia virus type II infection frequently goes undetected in contemporary US blood donors

Serologic screening for human T-cell leukemia virus type I (HTLV-I) infection was begun in US blood banks with the licensure of enzyme-linked immunosorbent assays (ELISA) in December 1988. We examined the donation histories of the first 60 Western blot (WB)-confirmed HTLV-I/II positive donors to one blood center and found 8 had made 16 previous donations that scored negative on the screening ELISA. All 16 donations had ELISA absorbance below the cutoff for a positive assay, but still well above that of the average donation (17.6% +/- 5.7% of the cutoff). In a more extensive study, 17 donations from a total of 61,752 at six blood centers were both ELISA-positive and WB-positive for HTLV-I (4) or HTLV-II (13), and 218 samples had ELISA absorbance greater than 50% of the ELISA cutoff. One hundred seventy-eight of the 218 were tested further by WB and 11 were found positive. All 11 positives were confirmed by polymerase chain reaction; 10 had HTLV-II and 1 had HTLV-I. Thus, the HTLV-I-based screening ELISA missed at least 10 of 23, or 43% (95% confidence interval, 23% to 66%), of HTLV-II infections, compared with 1 of 5, or 20%, of HTLV-I infections.     

Continuous display of presentations sharing clips

Databases were introduced to remove redundancy from conventional file systems and encouragesharing, which resulted in update anomalies when information was modified. With presentations (movies) sharing clips (sequence of frames), continuous display becomes challenging as well. Continuous display requires the system to retrieve the information with no disruptions or delays (hiccups) once a display is initiated. To ensure a continuous display using a multi-disk hardware platform, a video object is striped into subobjects. The system enforces a regular schedule on retrieval of each subobject by controlling the placement of the subobjects across the disks. Now if different presentations share subobjects, each presentation will enforce its own restrictions on the placement of the data, resulting in an irregular schedule. We investigate approaches to render a schedule regular for two alternative display paradigms: Demand and Data driven.     

Privatizing public housing in Canada,A public policy agenda

The new Progressive Conservative (PC) government in Ontario is planning to sell the 84,500 units (using the UK model) of public housing that it owns. This paper presents an evaluation of the programs to sell off public housing in the United Kingdom, the United States, and Canada. After a comparative evaluation, the author makes several recommendations for the Ontario government. The author argues that Canadian public-housing tenant characteristics are different from those in the UK. Ontario's public-housing tenants are too poor to purchase these units. They would be unable to maintain the unit and carry the costs (property tax, insurance, and utilities) even if the units were given to them free. The author concurs that the sale of public housing units in the USA and the UK may have generated some revenue and saved some costs. However, he points out that in the long run, the modest financial gains will be offset by higher operating costs. The sale of the best units and those that are easy to maintain, along with the loss of higher-income tenants, will no doubt result in higher average operating costs for the remaining Units. Such unintended consequences of the sale should be avoided by the Ontario government. The author recommends that the province develop a comprehensive and multi-purpose plan covering an array of programs (including the sale of some units) rather than concentrate exclusively on the sale.     

Blue fluorescent conductive poly(9,10‐di(1‐naphthalenyl)‐2‐vinylanthracene) homopolymer and its highly soluble copolymers with styrene or 9‐vinylcarbazole

A new blue fluorescent monomer, 9,10‐di(1‐naphthalenyl)‐2‐vinylanthracene, was designed and synthesized in good yield. Its homopolymer poly(9,10‐di(1‐naphthalenyl)‐2‐vinylanthracene) (P(ADN)) and soluble conductive vinyl copolymers poly[(9,10‐di(1‐naphthalenyl)‐2‐vinylanthracene)‐co‐styrene] (P(ADN‐co‐S)) and poly[(9,10‐di(1‐naphthalenyl)‐2‐vinylanthracene)‐co‐(9‐vinylcarbazole)] (P(ADN‐co‐VK)) were synthesized using free radical solution polymerization. All the polymers showed high glass transition mid‐point temperatures (203 to 237 °C) and good thermal stabilities. The photoluminescence emission of the copolymers was similar to that of P(ADN) (with two maxima at 423 and 442 nm). The lifetimes of P(ADN‐co‐S) (6.82 to 7.91 ns) were all slightly less than that of P(ADN) (8.40 ns). The lifetime of P(ADN‐co‐VK) increased from 7.8 to 8.8 ns with an increase in VK content. The fluorescence quantum yields of P(ADN‐co‐S) showed an overall increasing tendency from 0.42 to 0.58. The quantum efficiencies of P(ADN‐co‐VK) decreased from 0.36 to 0.19 with an increase of VK fraction. With increasing S/VK content, the highest occupied molecular orbital of P(ADN‐co‐S)/P(ADN‐co‐VK) ranged from ?5.58 to ?5.73 eV, which was similar to that of P(ADN) (?5.71 eV). The band gaps of P(ADN‐co‐S) and P(ADN‐co‐VK) were about 2.97 eV, which were equal to that of P(ADN), and smaller than that of 2‐methyl‐9,10‐di(1‐naphthalenyl)anthracene (MADN) (3.04 eV) and poly(9‐vinylcarbazole) (3.54 eV). Preliminary electroluminescence results were obtained for a homojunction device with the configuration ITO/MoO₃ (20 nm)/P(ADN)/LiF (1 nm)/Al (100 nm), which achieved only 30–50 cd m^?2, due to P(ADN) having a low mobility of 4.7 × 10^?8 cm² V^?1 s^?1 compared to that of its model compound MADN of 6.5 × 10^?4 cm² V^?1 s^?1. © 2013 Society of Chemical Industry     

Experimental investigation of losses and secondary flow in an axial compressor stage

A detailed investigation of a three-dimensional flow using both stationary and rotating pressure probes has been carried out in a low speed axial compressor stage. At the casing of a rotor row there is secondary flow produced by the relative motion of the annular wall to rotor blade tip and the tip clearance flow. At the hub a channel vortex can be observed. The value of the loss coefficient of both rotor and stator rows determined from conventional pressure probe data is affected by flow unsteadiness. This effect has been considered in detail. As a result, the probes should be dynamically calibrated. The rotor and stator blade elements loss at mid-span approximately equals two-dimensional cascade loss, when the data of probes exposed to strong flow unsteadiness have been corrected. This work was done for CKD-Works in Prague. The author is grateful to Dr.Svoboda of CKD for the permission to publish the results. Thanks are also due to Dr.Z. Moravec and Dr.J. Citavy for useful discussions.     

Optimal group route query: Finding itinerary for group of users in spatial databases

The increasing popularity of location-based applications creates new opportunities for users to travel together. In this paper, we study a novel spatio-social optimization problem , i.e., Optimal Group Route, for multi-user itinerary planning. With our problem formulation, users can individually specify sources and destinations, preferences on the Point-of-interest (POI) categories, as well as the distance constraints. The goal is to find a itinerary that can be traversed by all the users while maximizing the group’s preference of POI categories in the itinerary. Our work advances existing group trip planning studies by maximizing the group’s social experience. To this end, individual preferences of POI categories are aggregated by considering the agreement and disagreement among group members. Furthermore, planning a multi-user itinerary on large road networks is computationally challenging. We propose two efficient greedy algorithms with bounded approximation ratio, one exact solution which computes the optimal itinerary by exploring a limited number of paths in the road network, and a scaled approximation algorithm to speed up the dynamic programming employed by the exact solution. We conduct extensive empirical evaluations on two real-world road network/POI datasets and our results confirm the effectiveness and efficiency of our solutions.     

TAPAS: Trustworthy privacy-aware participatory sensing

With the advent of mobile technology, a new class of applications, called participatory sensing (PS), is emerging, with which the ubiquity of mobile devices is exploited to collect data at scale. However, privacy and trust are the two significant barriers to the success of any PS system. First, the participants may not want to associate themselves with the collected data. Second, the validity of the contributed data is not verified, since the intention of the participants is not always clear. In this paper, we formally define the problem of privacy and trust in PS systems and examine its challenges. We propose a trustworthy privacy-aware framework for PS systems dubbed TAPAS, which enables the participation of the users without compromising their privacy while improving the trustworthiness of the collected data. Our experimental evaluations verify the applicability of our proposed approaches and demonstrate their efficiency.