Environmental aspects of the use of NTA as a detergent builder

The behaviour, fate and significance of the detergent builder nitrilotriacetic acid (NTA) has been reviewed with particular reference to the removal of NTA during wastewater treatment and the effects of NTA on heavy metal solubility both during treatment and in the receiving environment. It is concluded that NTA removal during secondary biological treatment is subject to considerable variation, both temporal and between works as a result of changes in NTA load, temperature, water hardness and treatment process parameters. As a result of such variability, effluent NTA concentrations may be sufficient to mobilise heavy metals resulting in metal contamination of receiving waters and potable waters, particularly in areas of low effluent dilution and high water re-use. Removal of NTA during primary sedimentation and septic tank treatment is concluded to be predominantly due to adsorption to the sludge solids while removal in anaerobic sludge digestion is subject to operational characteristics of the treatment works. Disposal of NTA contaminated sludge to land may contaminate groundwaters and affect heavy metal speciation, while the disposal of contaminated sludge or sewage to sea may result in toxic algal blooms, in addition to effects on metal speciation.     

Appropriate energy efficient building envelope technologies for social housing in the Irish climate

Extensive dynamic thermal simulation parametric analyses have been undertaken of energy efficient fabric alterations to social housing in Northern Ireland culminating in priorities for deployment. Five ȁ8basecaseȁ9 simulation models were used to represent the predominant characteristics of the existing social housing stock. The majority of technologies studied provided annual space-heating energy savings of more than 10%. The variation of energy savings and economic performance across the basecases highlights the value of a dwelling specific approach to selecting energy efficient building envelope technology solutions for energy rehabilitation programmes. The paper further outlines a framework for prioritising appropriate energy efficient building envelope technological solutions for a large regional building stock, i.e. existing social housing stock in Northern Ireland, highlighting influential parameters. An energy efficient building envelope inter-technology ranking approach provides a method of comparison across the various different dwellings in the regional housing stock. Airtightness ranked consistently highest across the dwellings studied with some solar technologies performing better than more technologically mature solutions such as insulation.     

High-frequency dual mode pulsed wave Doppler imaging for monitoring the functional regeneration of adult zebrafish hearts

Adult zebrafish is a well-known small animal model for studying heart regeneration. Although the regeneration of scars made by resecting the ventricular apex has been visualized with histological methods, there is no adequate imaging tool for tracking the functional recovery of the damaged heart. For this reason, high-frequency Doppler echocardiography using dual mode pulsed wave Doppler, which provides both tissue Doppler (TD) and Doppler flow in a same cardiac cycle, is developed with a 30 MHz high-frequency array ultrasound imaging system. Phantom studies show that the Doppler flow mode of the dual mode is capable of measuring the flow velocity from 0.1 to 15 cm s⁻¹ with high accuracy (p-value = 0.974 > 0.05). In the in vivo study of zebrafish, both TD and Doppler flow signals were simultaneously obtained from the zebrafish heart for the first time, and the synchronized valve motions with the blood flow signals were identified. In the longitudinal study on the zebrafish heart regeneration, the parameters for diagnosing the diastolic dysfunction, for example, E/Em < 10, E/A < 0.14 for wild-type zebrafish, were measured, and the type of diastolic dysfunction caused by the amputation was found to be similar to the restrictive filling. The diastolic function was fully recovered within four weeks post-amputation.     

Deuterium enrichment using vanadium membranes

Hydrogen isotope selectivity of palladium membranes has long been known and studied, but the emergence of vanadium-based membranes as a low-cost alternative naturally inspires curiosity as to whether these membranes exhibit similar properties. Accordingly, experiments to calculate the permeability of hydrogen and deuterium through a palladium-coated vanadium membrane at 300 °C were undertaken, and they revealed that hydrogen permeates at a rate 1.5 × faster than deuterium. With hydrogen absorption experiments at the same temperature showing very little difference in the amount of each isotope absorbed over a wide pressure range, it can be concluded that atomic hydrogen diffuses through vanadium 1.5 × faster than atomic deuterium.In practice, this gives rise to a significant separation factor, with deuterium being depleted in the permeate stream, but enriched in the retentate stream. Creating a cascading series of membranes, with successive retentate streams combined, will allow the deuterium concentration to be enriched far beyond the natural value of 0.015%. This work suggests that further work is warranted to explore whether this separation factor can be enhanced (e.g., through alloying), and to demonstrate a cascading membrane system to deliver high purity deuterium from a natural hydrogen source.     

Numerical Modeling of Multimaterial Thermoelectric Devices Under Static and Cyclic Thermal Loading

Selection of materials for thermoelectric devices is generally based on a figure of merit that is a function of the Seebeck coefficient, electrical conductivity, and thermal conductivity. While this figure of merit is a useful metric for comparing materials, the relative importance of the constituent properties depends on the particular application and conditions. In addition, multiple materials can be used together to improve the performance or extend the operating range, and determining the performance of such multimaterial combinations requires analysis beyond simply averaging the properties of the constituent materials. In this paper, finite-element numerical simulations under static and cyclic thermal loadings are used to investigate how device performance can be improved by judicious location of the different materials within the device. The results show that the performance of a device with two different materials can be better than that of either of the individual materials. The greatest improvement in performance occurs with cyclic heating, where the overall performance is strongly influenced by the behavior under transient conditions during heating and cooling.     

A music symbols recognition method using pattern matching along with integrated projection and morphological operation techniques

Multimedia Tools and Applications - Optical Music Recognition (OMR) can be divided into three main phases: (i) staff line detection and removal. The goal of this phase is to detect and to remove...     

Computational fluid dynamics (CFD) investigation of air flow and temperature distribution in a small scale bread-baking oven

Experimental and computational fluid dynamics (CFD) analyses of the thermal air flow distribution in a 3-zone small scale forced convection bread-baking oven are undertaken. Following industrial bread-making practise, the oven is controlled at different (constant) temperatures within each zone and a CFD model is developed and validated against experimental data collected within the oven. The CFD results demonstrate that careful selection of the flow model, together with implementation of realistic boundary conditions, give accurate temperature predictions throughout the oven. The CFD model is used to predict the flow and thermal fields within the oven and to show how key features, such as regions of recirculating flow, depend on the speeds of the impinging jets.     

Use of mass loading to operate a thin film ultrasonic transducer in the 300 kHz–10 MHz frequency range

Thin film ultrasonic transducers have been designed which operate over an important frequency range, 300 kHz to 10 MHz. The transducers were made using piezoelectric aluminium nitride films a few microns thick. The films would have a fundamental thickness mode resonance at 1–3 GHz if fabricated as an unsupported film, however operation at much lower frequencies has been demonstrated when the transducers are fabricated on bulk substrates. This would enables them to be used in ultrasonic non-destructive testing in circumstances where the film can be deposited directly onto the object under test. We have found that the major factors influencing the below-resonance operation of the thin film transducers are the device impedance, the spectrum of the excitation pulse, and any mechanical (mass) loading applied to the back face of the transducer. Results are presented showing that the evolution of device impedance as a function of device area could be predicted using a PSpice model of the thin film transducer. The ability of the transducer to generate longitudinal mode pulses rather than shear wave pulses was found to depend on increasing the mechanical loading at the back face of the transducer. This mechanism for pulse generation was confirmed by Finite Element Modelling using PZFlex.     

Problem resolution support for free flight operations

The MITRE Corporation's Center for Advanced Aviation System Development (CAASD) has been conducting research into new automation capabilities to support free flight operations. One of these capabilities is a problem resolution function to assist the en route sector controller team in handling the more complex traffic patterns that can result from a less structured free flight environment. This function is termed problem analysis, resolution and ranking (PARR). PARR is envisaged as an enhancement to the user request evaluation tool (URET) free flight phase 1 (FFP1) capability, and has been designated as priority research for the follow-on free flight phase 2 (FFP2) effort. PARR is being developed as a series of incremental enhancements, with the first step focusing on the resolution of aircraft-to-aircraft and aircraft-to-airspace problems. Follow-on enhancements include resolutions for metering and other traffic flow management (TFM) flow initiatives, resolutions for the avoidance of severe weather areas, and the integration into a common en route sector team CHI. A research management plan has been prepared by the Federal Aviation Administration and MITRE/CAASD to support this development process. The paper describes the initial PARR capabilities, along with an extension to incorporate assigned metering time constraints