Synthesis of a terpolymer and a tetrapolymer using monomers of diallylamine salts and SO<Subscript>2</Subscript> and their application as antiscalants

An aqueous solution of diallylammonium salts (CH₂ = CHCH₂)₂NH⁺(CH₂)₃A^? having A^? as: CO₂ ^? (I), PO₃H₂ Cl^? (II) and SO₃ ^? (III) in 1:1:1 mol ratio underwent ammonium persulfate-initiated ter cyclopolymerization to yield pH-responsive zwitterionic polymer IV with random placements of the monomers in the same ratio. During dialysis, PO₃H₂Cl^? of the incorporated monomer units of II upon depletion of HCl became PO₃H^?. Likewise, azobisisobutyronitrile-initiated cyclopolymerization of I, II, III, and SO₂ in a mole ratio of 1:1:1:3 provided pH-responsive tetrapolymer V in over 90 % yield with random and alternative placements of I–III and SO₂ units, respectively, in the same ratio as the feed. Polyzwitterions (PZs) IV and V were insoluble in salt-free water but soluble in the presence of salts. The critical salt concentrations required to promote water solubility of PZ IV were determined to be 0.356 M NaCl, 0.237 M NaBr and 0.128 M NaI, whereas for PZ V the corresponding values were found to be 2.25, 1.26 and 0.862 M, respectively. PZs IV and V were converted into anionic polyelectrolytes VI and VII upon basification with NaOH. The viscosity and antiscalant behaviors of VI and VII were examined. The polymers demonstrated remarkable scale inhibition efficacies; at a dose of 10 ppm, both IV (+NaOH) and V (+NaOH) delayed the precipitation of CaSO₄ from its supersaturated solution up to 920 and over 4000 min, respectively. For a small concentration of 5 ppm of polymer V, a scale inhibition of 100 % over 100 min verified it to be a potential effective antiscalant additive in reverse osmosis plants.     

Bionic Prototyping of Honeycomb Patterned Polymer Composite and Its Engineering Application

Polymeric honeycombs have always enticed researchers due to their lightweight, high stiffness-to-weight ratio, and well developed energy absorption characteristics, owing which they find themselves extensively used in automotive and aerospace engineering. Simultaneously, additive manufacturing methodologies offers enticing pathway for prototyping of functional materials starring complex heterogeneous structural designs with varying wall thickness inspired from biological systems, paving way for augmenting the mechanical and physical properties for specifically tailored applications. We have portrayed potential and possible challenges for 3D printing for prototyping of polymeric honeycomb composites, not constrained by existing engineering principles, offering designer proficiency to build resilient architectures.     

A carbon nanotube-based composite for the thermal control of heat loads

Design optimization of an encapsulated carbon composite thermal control (TC) system is presented. The composite TC system consists of multiple phase change materials (PCM) doped with carbon nanotubes and enclosed in a casing of carbon/carbon composite sheets. Using the concept of global thermal resistance an analytical model was formulated to predict the transient temperature distribution through the composite system. The temperature data was then used to estimate maximum energy storage and heat dissipation rates. A substantial reduction in weight and size of the TC composite was observed corresponding to the optimized design. The use of carbon nanotubes both as additives with optimal loading and as a thermal interface material significantly reduced the maximum junction temperatures for different constant power loads for the multiple PCM composite as compared to its original size used for the experimental work. The optimized composite minimized the total thermal resistance through the composite sample and thereby increased its thermal response as indicated by approximately 4 times increase in the heat dissipation rate.     

Kinetics of oxidative cracking of n‐hexane to olefins over VOx/Ce‐Al2O3 under gas phase oxygen‐free environment

The kinetics of oxidative cracking of n‐hexane to olefins using lattice oxygen of VO_x/Ce‐Al₂O₃ is investigated. The TPR/TPO analysis shows a consistent reducibility (79%) of VO_x/Ce‐Al₂O₃ in repeated redox cycles. The total acidity of the sample is found to be 0.54 mmol/g with 22% are strong acid sites that favors olefin selectivity. The oxidative cracking of n‐hexane in a fluidized CREC Riser simulator gives approximately 60% olefin selectivity at 30% n‐hexane conversion. A kinetic model is developed considering (1) cracking, (2) oxidative dehydrogenation (ODH), and (3) catalyst deactivations. The proposed cracking mechanism considers adsorption, C–H and C–C bond fission and desorption as elementary steps and implemented by pseudo steady state hypothesis. A Langmuir‐Hinshelwood mechanism is found to represent the ODH reactions. The developed model fits the experimental data with favorable statistical indicators. The estimated specific reaction rate constants are also found to be consistent with the product selectivity data. © 2016 American Institute of Chemical Engineers AIChE J, 63: 130–138, 2017     

A new methodology for hydrodynamic similarity in bubble columns

A new hypothesis has been proposed in this work for hydrodynamic similarity that can be subsequently used for scale‐up of bubble column reactors. The proposed hypothesis takes into account both global (by matching overall gas holdup) as well as local hydrodynamics (by matching time‐averaged radial profile/cross‐sectional distribution of gas holdup) to maintain similarity in two systems. The evaluation of proposed hypothesis has been accomplished utilising advanced diagnostic techniques such as gamma‐ray computed tomography (CT) and computer automated radioactive particle tracking (CARPT). In this work, we experimentally demonstrate that similarity based only on global hydrodynamics does not necessarily ensure similar mixing and turbulence in two systems. It is essential to maintain similar global as well as local hydrodynamics. The hydrodynamic similarity that can be obtained by matching the commonly used dimensionless groups was also evaluated at these experimental conditions.     

Catalytic performance of Ni/CeO2/Al2O3 modified with noble metals in steam gasification of biomass

In the steam gasification of biomass, the additive effect of noble metals such as Pt, Pd, Rh and Ru to the Ni/CeO₂/Al₂O₃ catalyst was investigated. Among these noble metals, the addition of Pt was most effective even when the loading amount of added Pt was as small as 0.01 wt.%. In addition, the catalyst characterization suggests the formation of the Pt–Ni alloy over the Pt/Ni/CeO₂/Al₂O₃.     

FPGA：挑战带来新机遇

Aitera:依靠40nm与灵活性突围 谈及未来FPGA的发展趋势,Altera亚太区副总裁兼董事总经理Erhaan Shaikh认为对于面向全球市场采用了单芯片方案的新产品,在不同地区市场上推出时需要提供各种各样的型号产品.     

SENTIMENT ASSESSMENT OF TEXT BY ANALYZING LINGUISTIC FEATURES AND CONTEXTUAL VALENCE ASSIGNMENT

Text is not only an important medium to describe facts and events, but also to effectively communicate information about the writer's positive or negative sentiment underlying an opinion, or to express an affective or emotional state, such as happiness, fearfulness, surpriseness, and so on. We consider sentiment assessment and emotion sensing from text as two different problems, whereby sentiment assessment is the task that we want to solve first. Thus, this article presents an approach to sentiment assessment, i.e., the recognition of negative or positive valence of a sentence. For the purpose of sentiment recognition from text, we perform semantic dependency analysis on the semantic verb frames of each sentence, and then apply a set of rules to each dependency relation to calculate the contextual valence of the whole sentence. By employing a domain-independent, rule-based approach our system is able to automatically identify sentence-level sentiment. A linguistic tool called “SenseNet” has been developed to recognize sentiments in text, and to visualize the detected sentiments. We conducted several experiments with a variety of datasets containing data from different domains. The obtained results indicate significant performance gains over existing state-of-the-art approaches.     

A new image binarization method using iterative partitioning

This paper proposes a new method for image binarization that uses an iterative partitioning approach. The proposed method has been tested towards binarization of both document and graphic images. The quantitative comparisons with other standard methods reveal that the proposed approach outperforms existing widely used binarization techniques in terms of accuracy of binarization. The experimental results further establish the superiority of the proposed method, especially for degraded documents and graphic images. The proposed algorithm is suitable for a multi-core processing environment as it can be split into multiple parallel units of executions after the initial partitioning.     

Adaptive Automated Teller Machines

Nowadays, Automated Teller Machines (ATMs) provide significant online support to bank customers. A limitation of ATM usage is that customers often have to wait in a queue, especially at ATMs installed at busy locations. Also, old people tend to consume more ATM usage time, possibly frustrating customers in the queue. In these situations, ATMs should “adapt” to the behavior of the customers to minimize the usage time. To this end, we apply data mining techniques to an ATM transaction dataset obtained from an international bank based in Kuwait. We pre-process this dataset, and convert it into a specific XML format to mine it through the ProM (process mining) tool. Our results reveal that customers withdraw money most frequently, followed by purchases (through an ATM card) and balance inquiry transactions. Customers re-do these transactions frequently, and also employ them one after the other. We acquire the distributions of the withdrawn amount, based on individual customers, the location (ATM terminal) and time of the withdrawl. Based on these results, we have proposed a set of five adaptive ATM interfaces, which show only frequent transactions and frequently-withdrawn amounts, display the current balance autonomously, and query explicitly for viewing purchase history, or for performing another withdrawl. An online survey on 216 ATM customers reveals that a majority of customers are willing to use these interfaces for minimizing their usage time. Our work has been approved by the banking authority of Pakistan, and we are currently implementing our interfaces for a Pakistani bank.