The synthesis and crystal structure of unsubstituted 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY)

The fully unsubstituted 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) was synthesized for the first time by oxidation of dipyrromethane followed by treatment with boron trifluoride diethyl etherate in the presence of a base. The compound was fully characterized and its X-ray crystal structure is reported.     

Water Quality Modeling of Lake Michigan and Consideration of the Anomalous Ice Cover of 1976–1977

An intensive survey of water quality parameters was conducted on Lake Michigan during 1976 and 1977. A dynamic phytoplankton simulation model (MICH1) was developed to investigate the observed field data and to use in forecasting lake responses to various phosphorus loading scenarios. The 1977 data indicated that the southern basin of Lake Michigan lost up to 3 μg P/ L compared to concentrations observed in 1976. In an attempt to simulate this rapid depletion of phosphorus, MICH1 required an implicit representation of suspected effects of an extensive ice cover observed during the winter of 1976–77. This included increasing the net apparent settling rate eight fold during ice cover. A total phosphorus model (TPM) was used in conjunction with MICH1 ;for forecasting. These forecasts indicate a steady-state total phosphorus concentration of 7 μg P/ L, given a target load recommended by the 1978 Water Quality Agreement. The projected time to obtain 95% of steady-state response to a load change was 7–14 years.     

The investigation of basic processes of rapidly hardening wood-cement-water mixture with CO2

The rapid hardening of wood-cement-water mixture in a carbon dioxide enriched environment was investigated, by studying the development of carbonation degree and monitoring the phase changes in the mixture. The carbonation reaction was a diffusion-controlled process. It occurred very quickly in the first two minutes of reaction. After that, its rate decreased drastically, due to the increasing difficulty of transporting reactants to reaction sites. Jander’s model was found ineffective in predicting the carbonation process. However, its modified version, developed by Kroger and Ziegler, could describe this progress accurately. In addition, the rapid hardening appeared to result mainly from the reactions of calcium silicates in cement with carbon dioxide. The reaction between ettringite and carbon dioxide might also contribute to this rapid hardening process. However, the reaction between calcium hydroxide and carbon dioxide was not confirmed.     

Conductive Anodic Filament (CAF) Formation Part I: the Influence of Water-Soluble Flux on Its Formation

Conductive anodic filament (CAF) formation has been studied for a number of years, but the mechanism of its formation has not previously been defined. In 2002, Ready identified CAF as atacamite, Cu₂(OH)₃Cl. Electrochemical studies have shown that both CuCl and CuCl₂⁻ participate in the formation of Cu₂(OH)₃Cl, with the predominating species being CuCl. This paper proposes a mechanism for CAF formation based on x-ray photoelectron spectroscopy. The data show that CuCl is the precursor to the formation of Cu₂(OH)₃Cl in the presence of oxygen and water. Earlier, Meeker and Lu Valle had proposed that CAF failure is best represented by two competing reactions: the formation of a copper chloride corrosion compound (now identified as Cu₂(OH)₃Cl) and the formation of innocuous trapped chlorine compounds. Since no evidence of any trapped chloride compounds has been found, we propose that the formation of CAF is best represented by a single nonreversible reaction.     

RTO: An overview and assessment of current practice

The practice of implementing real-time optimization (RTO) using a rigorous steady-state model, in conjunction with model predictive control (MPC), dates back to the late 1980s. Since then, numerous projects have been implemented in refinery and chemical plants, and RTO has received significant attention in the industrial and academic literature. This history affords us the opportunity to assess the impact and success of RTO technology in the process industries. We begin with a discussion of the role RTO serves in the hierarchy of control and optimization decision making in the plant, and outline the key steps of the RTO layer and the coordination with MPC. Where appropriate, we point out the different approaches that have been used in practice and discuss the success factors that directly relate to the success of RTO within an organization. We also discuss alternative approaches that have been used to alleviate some of the challenges associated with implementing RTO and which may be appropriate for those unwilling to commit to the traditional RTO approach. Lastly, we provide suggestions for improvement to motivate further research.     

Temporary bond—debond technology for high‐performance transistors on flexible substrates

Abstract— A processing technology based upon a temporary bond—debond approach has been developed that enables direct fabrication of high‐performance electronic devices on flexible substrates. This technique facilitates processing of flexible plastic and metal‐foil substrates through automated standard semiconductor and flat‐panel tool sets without tool modification. The key to processing with these tool sets is rigidifying the flexible substrates through temporary bonding to carriers that can be handled in a similar manner as silicon wafers or glass substrates in conventional electronics manufacturing. To demonstrate the power of this processing technology, amorphous‐silicon thin‐film‐transistor (a‐Si:H TFT) backplanes designed for electrophoretic displays (EPDs) were fabricated using a low‐temperature process (180°C) on bonded‐plastic and metal‐foil substrates. The electrical characteristics of the TFTs fabricated on flexible substrates are found to be consistent with those processed with identical conditions on rigid silicon wafers. These TFTs on plastic exhibit a field‐effect mobility of 0.77 cm²/V‐sec, on/off current ratio >10⁹ at Vds = 10 V, sub‐threshold swing of 365 mV/dec, threshold voltage of 0.49 V, and leakage current lower than 2 pA/μm gate width. After full TFT‐array fabrication on the bonded substrate and subsequent debonding, the flexible substrate retains its original flexibility; this enables bending of the EPD display without loss in performance.     

Transfer formalisms

We discuss some different ideas about the sort of formalism appropriate for translation (more specifically, transfer) that have been explored within Eurotra. The intention is not to evaluate these different ideas, but to outline the issues of general interest and relevance that they raise. Section 1 describes some common assumptions, section 2 describes the different ways they have been interpreted, and section 3 considers some further implications.     

Target coverage in camera networks for manufacturing workplaces

In this paper, we investigate the camera network placement problem for target coverage in manufacturing workplaces. The problem is formulated to find the minimum number of cameras of different types and their best configurations to maximise the coverage of the monitored workplace such that the given set of target points of interest are each k-covered with a predefined minimum spatial resolution. Since the problem is NP-complete, and even NP-hard to approximate, a novel method based on Simulated Annealing is presented to solve the optimisation problem. A new neighbourhood generation function is proposed to handle the discrete nature of the problem. The visual coverage is modelled using realistic and coherent assumptions of camera intrinsic and extrinsic parameters making it suitable for many real world camera based applications. Task-specific quality of coverage measure is proposed to assist selecting the best among the set of camera network placements with equal coverage. A 3D CAD of the monitored space is used to examine physical occlusions of target points. The results show the accuracy, efficiency and scalability of the presented solution method; which can be applied effectively in the design of practical camera networks.     

Adding precise nanoliter volume capabilities to liquid-handling automation for compound screening experimentation

Miniaturizing experimental sample volumes to the nanoliter volume range is one of the most economical ways to perform mid- and high-throughput compound screening experiments. Existing automation platforms for nanoliter fluid handling can be bulky, expensive, and require periodic calibration to provide consistent liquid dispensing. In addition, even with frequent calibration, significant instrument-to-instrument variation in low-volume dispensing can occur between different instrument platforms. Many of these issues can be addressed by the use of PocketTips. PocketTips are tips with a defined internal pocket designed to hold specific nanoliter volumes of compound dissolved in dimethylsulfoxide. Although the overall liquid-handling process with PocketTips uses the aspirate/dispense features of the specific liquid-handling device being used, the dispensed nanoliter volume is solely based on the dimensions of the pocket of the PocketTip and thus, the liquid-handling device itself need not have nanoliter dispensing capabilities. In this report, we demonstrate the performance of PocketTips on different automation platforms. In addition, we used a cell-based ?-lactamase reporter assay system to demonstrate that compound delivery by PocketTips compares favorably with a standard compound addition technique.