Smart meter devices and the effect of feedback on residential electricity consumption: Evidence from a natural experiment in Northern Ireland

Using a unique set of data and exploiting a large-scale natural experiment, we estimate the effect of real-time usage information on residential electricity consumption in Northern Ireland. Starting in April 2002, the utility replaced prepayment meters with advanced meters that allow the consumer to track usage in real-time. We rely on this event, account for the endogeneity of price and payment plan with consumption through a plan selection correction term, and find that the provision of information is associated with a decline in electricity consumption of 11-17%. We find that the reduction is robust to different specifications, selection-bias correction methods and subsamples of the original data. The advanced metering program delivers reasonably cost-effective reductions in carbon dioxide emissions, even under the most conservative usage reduction scenarios.

Design and physicochemical characterisation of a bioadhesive patch for dose-controlled topical delivery of imiquimod

Clinical use of the imidazoquinoline immunomodulator imiquimod for the topical treatment of dysplastic and neoplastic lesions has increased markedly in recent years. However, despite guidance from the manufacturer of the proprietary imiquimod cream, there seems to be little consensus between clinicians as to the topically applied dose. Given that patients often apply the cream themselves at home, further dosing variability is expected and, consequently, accurate comparison of the results of different published studies is dif?cult. This paper describes, for the ?rst time, the formulation and physicochemical characterisation of a bioadhesive patch for dose-controlled topical delivery of imiquimod as well as a new HPLC method for sensitive ?uorescence determination of imiquimod released from such systems. Patches containing imiquimod loadings of 4.75, 9.50 and 12.50 mg cm-2 all released signi?cantly more drug across a model membrane than the proprietary cream over a period of 6 h. Inclusion of imiquimod in patches did not adversely affect their physicochemical properties. Of major importance, patches contained de?ned drug loadings per unit area; therefore, their use could reduce inter-clinician variability. This would make critical comparison of clinical studies and determination of an appropriate imiquimod dose for successful treatment much simpler. Since bioadhesive formulations are capable of adhering to body tissues in moist environments, the use of a bioadhesive patch system may allow extension of the clinical uses of imiquimod to the treatment of neoplastic conditions of the oral cavity and cervix, as well as the vulva. © 2005 Elsevier B.V. All rights reserved.

An automated machine vision system for the histological grading of cervical intraepithelial neoplasia (CIN)

The histological grading of cervical intraepithelial neoplasia (CIN) remains subjective, resulting in inter- and intra-observer variation and poor reproducibility in the grading of cervical lesions. This study has attempted to develop an objective grading system using automated machine vision. The architectural features of cervical squamous epithelium are quantitatively analysed using a combination of computerized digital image processing and Delaunay triangulation analysis; 230 images digitally captured from cases previously classified by a gynaecological pathologist included normal cervical squamous epithelium (n = 30), koilocytosis (n = 46), CIN 1 (n = 52), CIN 2 (n = 56), and CIN 3 (n=46). Intra- and inter-observer variation had kappa values of 0.502 and 0.415, respectively. A machine vision system was developed in KS400 macro programming language to segment and mark the centres of all nuclei within the epithelium. By object-oriented analysis of image components, the positional information of nuclei was used to construct a Delaunay triangulation mesh. Each mesh was analysed to compute triangle dimensions including the mean triangle area, the mean triangle edge length, and the number of triangles per unit area, giving an individual quantitative profile of measurements for each case. Discriminant analysis of the geometric data revealed the significant discriminatory variables from which a classification score was derived. The scoring system distinguished between normal and CIN 3 in 98.7% of cases and between koilocytosis and CIN 1 in 76.5% of cases, but only 62.3% of the CIN cases were classified into the correct group, with the CIN 2 group showing the highest rate of misclassification. Graphical plots of triangulation data demonstrated the continuum of morphological change from normal squamous epithelium to the highest grade of CIN, with overlapping of the groups originally defined by the pathologists. This study shows that automated location of nuclei in cervical biopsies using computerized image analysis is possible. Analysis of positional information enables quantitative evaluation of architectural features in CIN using Delaunay triangulation meshes, which is effective in the objective classification of CIN. This demonstrates the future potential of automated machine vision systems in diagnostic histopathology. Copyright (C) 2000 John Wiley and Sons, Ltd.

Modelling the mechanical response of the reed-mouthpiece-lip system of a clarinet. Part II: A lumped model approximation

A non-linear lumped model of the reed-mouthpiece-lip system of a clarinet is formulated, in which the lumped parameters are derived from numerical experiments with a finite-difference simulation based on a distributed reed model. The effective stiffness per unit area is formulated as a function of the pressure signal driving the reed, in order to simulate the effects of the reed bending against the lay, and mass and damping terms are added as a first approximation to the dynamic behaviour of the reed. A discrete-time formulation is presented, and its response is compared to that of the distributed model. In addition, the lumped model is applied in the simulation of clarinet tones, enabling the analysis of the effects of using a pressure-dependent stiffness per unit area on sustained oscillations. The analysed effects and features are in qualitative agreement with players' experiences and experimental results obtained in prior studies.

Power Stored and Quality Factors in Frequency Selective Surfaces at THz Frequencies

A study of the external, loaded and unloaded quality factors for frequency selective surfaces (FSSs) is presented. The study is focused on THz frequencies between 5 and 30 THz, where ohmic losses arising from the conductors become important. The influence of material properties, such as metal thickness, conductivity dispersion and surface roughness, is investigated. An equivalent circuit that models the FSS in the presence of ohmic losses is introduced and validated by means of full-wave results. Using both full-wave methods as well as a circuit model, the reactive energy stored in the vicinity of the FSS at resonance upon plane-wave incidence is presented. By studying a doubly periodic array of aluminium strips, it is revealed that the reactive power stored at resonance increases rapidly with increasing periodicity. Moreover, it is demonstrated that arrays with larger periodicity-and therefore less metallisation per unit area-exhibit stronger thermal absorption. Despite this absorption, arrays with higher periodicities produce higher unloaded quality factors. Finally, experimental results of a fabricated prototype operating at 14 THz are presented.

Shell scarring in Calliostoma zizyphinum (Prosobranch: Trochidae) from Strangford Lough, Northern Ireland.

Pink and white shells of Calliostoma zizyphinum show both undamaged and damaged scars. White shelled individuals predominate in Strangford Lough, Northern Ireland where Calliostoma densities and scarring levels are high. No white shells were found intertidally, outside the entrance channel to the Lough. Significant differences occur in the size of Calliostoma shells between sampling sites but not between different colour morphs at each site. However in pooled samples, pink individuals are significantly larger than white individuals. When sites and morphs are considered separately, pink Calliostoma density is negatively correlated with water movement. At sites where pink Calliostoma occur, the percentage of pink shelled individuals is negatively correlated with total Calliostoma density. Damaged and undamaged scarring values per unit area of shell, show highly significant differences between sites and damaged scars are significantly higher in white individuals. Undamaged scars are not correlated with any of the environmental parameters recorded, but are positively correlated with damaged scars suggesting a common causative factor. The level of damaged scarring is positively correlated with crab/total Calliostoma ratio at all sites and where each colour morph was considered separately. Multiple regression analyses reveal that crab/Calliostoma ratios account for 42% of the between site variation in damaged scars. Significantly higher levels of damaged scars are found at sites with high crab densities and significantly larger individuals are found at sites where crab densities are intermediate in value. The largest and most highly scarred individuals occur at sites with most coarse substrata where Calliostoma are present in their lowest densities. The higher scarring levels and smaller size of white individuals reflect either higher mortality or reduced growth in white shelled Calliostoma.

OXIDATION OF CHLORIDE TO CHLORINE BY CEIV IONS MEDIATED BY DIFFERENT RUIV AND IRIV OXIDE-BASED CATALYSTS

A number of different, characterised, supported and unsupported oxides of Ru(IV) and Ir(IV) have been tested for activity as a chlorine catalyst in the oxidation of brine by Ce(IV) ions. All the different materials tested gave yields of chlorine of > 90% and first-order kinetics for the reduction of the Ce(IV) ions. The samples prepared by the Adams method were the most active of the materials tested and are typified by high surface areas and appreciable activities per unit area. The kinetics of the catalysed reduction of Ce(IV) ions by brine were studied in detail using an Ru(IV) oxide prepared by the Adams method and supported on TiO2 and the results were rationalised in terms of an electrochemical model in which the rate-determining step is the diffusion-controlled reduction of Ce(IV) ions. In support of this model the measured activation energies for the oxidation of brine by Ce(IV) ions, catalysed by either a supported or unsupported Adams catalyst, were both close (18-21 kJ mol-1) to that expected for a diffusion-controlled reaction (ca. 15 kJ mol-1).

COMPARATIVE-STUDY OF NEW AND ESTABLISHED HETEROGENEOUS OXYGEN CATALYSTS

The kinetics of catalysis of a number of new and established heterogeneous O2 catalysts have been studied using Ce(IV) as the oxidant via both the disappearance of the Ce(IV) ions and concomitant appearance of O2. The most active of the catalysts tested utilised a PGM(IV) oxide, usually Ru or Ir, prepared by the Adams method, which appears to generate microcrystalline powders with high surface areas and optimum activities per unit area.

FPGA Implementations of the Round Two SHA-3 Candidates

The second round of the NIST-run public competition is underway to find a new hash algorithm(s) for inclusion in the NIST Secure Hash Standard (SHA-3). This paper presents the full implementations of all of the second round candidates in hardware with all of their variants. In order to determine their computational efficiency, an important aspect in NIST's round two evaluation criteria, this paper gives an area/speed comparison of each design both with and without a hardware interface, thereby giving an overall impression of their performance in resource constrained and resource abundant environments. The implementation results are provided for a Virtex-5 FPGA device. The efficiency of the architectures for the hash functions are compared in terms of throughput per unit area. To the best of the authors' knowledge, this is the first work to date to present hardware designs which test for all message digest sizes (224, 256, 384, 512), and also the only work to include the padding as part of the hardware for the SHA-3 hash functions.

Inorganic arsenic contents in rice-based infant foods from Spain, UK, China and USA

Spanish gluten-free rice, cereals with gluten, and pureed baby foods were analysed for total (t-As) and inorganic As (i-As) using ICP-MS and HPLC-ICP-MS, respectively. Besides, pure infant rice from China, USA, UK and Spain were also analysed. The i-As contents were significantly higher in gluten-free rice than in cereals mixtures with gluten, placing infants with celiac disease at high risk. All rice-based products displayed a high i-As content, with values being above 60% of the t-As content and the remainder being dimethylarsinic acid (DMA). Approximately 77% of the pure infant rice samples showed contents below 150 µg kg(-1) (Chinese limit). When daily intake of i-As by infants (4-12 months) was estimated and expressed on a bodyweight basis (µg d(-1) kg(-1)), it was higher in all infants aged 8-12 months than drinking water maximum exposures predicted for adults (assuming 1 L consumption per day for a 10 µg L(-1) standard).

A pseudo-transient solution strategy for the analysis of delamination by means of interface elements

Recent efforts in the finite element modelling of delamination have concentrated on the development of cohesive interface elements. These are characterised by a bilinear constitutive law, where there is an initial high positive stiffness until a threshold stress level is reached, followed by a negative tangent stiffness representing softening (or damage evolution). Complete decohesion occurs when the amount of work done per unit area of crack surface is equal to a critical strain energy release rate. It is difficult to achieve a stable, oscillation-free solution beyond the onset of damage, using standard implicit quasi-static methods, unless a very refined mesh is used. In the present paper, a new solution strategy is proposed based on a pseudo-transient formulation and demonstrated through the modelling of a double cantilever beam undergoing Mode I delamination. A detailed analysis into the sensitivity of the user-defined parameters is also presented. Comparisons with other published solutions using a quasi-static formulation show that the pseudo-transient formulation gives improved accuracy and oscillation-free results with coarser meshes

CHARACTERIZATION OF SURFACE-PLASMONS ON METAL-OXIDE-SEMICONDUCTOR STRUCTURES

Using the Otto (prism-air gap-sample) configuration p-polarized light of wavelength 632.8 nm has been coupled with greater than 80% efficiency to surface plasmons on the aluminium electrode of silicon-silicon dioxide-aluminium structures. The results show that if the average power per unit area dissipated on the metal film exceeds approximately 1 mW mm-2, then the coupling gap and thus the characteristics of the surface plasmon resonance are noticeably altered. In modelling the optical response of such systems the inclusion of both a non-uniform air coupling gap and a thin cermet layer at the aluminium surface may be necessary.

Cross-layer Energy-Efficiency Optimization of Packet Based Wireless MIMO Communication Systems

Energy in today's short-range wireless communication is mostly spent on the analog- and digital hardware rather than on radiated power. Hence,purely information-theoretic considerations fail to achieve the lowest energy per information bit and the optimization process must carefully consider the overall transceiver. In this paper, we propose to perform cross-layer optimization, based on an energy-aware rate adaptation scheme combined with a physical layer that is able to properly adjust its processing effort to the data rate and the channel conditions to minimize the energy consumption per information bit. This energy proportional behavior is enabled by extending the classical system modes with additional configuration parameters at the various layers. Fine grained models of the power consumption of the hardware are developed to provide awareness of the physical layer capabilities to the medium access control layer. The joint application of the proposed energy-aware rate adaptation and modifications to the physical layer of an IEEE802.11n system, improves energy-efficiency (averaged over many noise and channel realizations) in all considered scenarios by up to 44%.

Advanced design optimization of cold-formed steel portal frame buildings

The design optimization of cold-formed steel portal frame buildings is considered in this paper. The objective function is based on the cost of the members for the main frame and secondary members (i.e., purlins, girts, and cladding for walls and roofs) per unit area on the plan of the building. A real-coded niching genetic algorithm is used to minimize the cost of the frame and secondary members that are designed on the basis of ultimate limit state. It iis shown that the proposed algorithm shows effective and robust capacity in generating the optimal solution, owing to the population's diversity being maintained by applying the niching method. In the optimal design, the cost of purlins and side rails are shown to account for 25% of the total cost; the main frame members account for 27% of the total cost, claddings for the walls and roofs accounted for 27% of the total cost.

Evaluation of passive ventilation provision in domestic housing retrofit

Increasing energy efficiency in the residential sector, while maintaining adequate home ventilation for health and well-being, is proving to be a challenge. This study assesses the efficacy of passive ventilation strategies designed to comply with building regulations and imposed after housing energy-efficiency retrofits. In particular, it focuses on the provision of ventilation using background through-wall vents, which remains a common strategy in a number of European countries including Ireland and the UK, where vent sizes, related to floor area, are stipulated in building regulations. A collective of social housing, with background through-wall vents installed post thermal retrofit, is taken as a case study. These homes are modelled to interrogate the impact of the passive ventilation strategy on house air exchange rate and thermal heating energy loads. The reaction of occupants to through-wall vent installation is decidedly negative and many block vents to limit thermal discomfort and heat loss. Simulation studies show significant external air ingress through vents. A wide range of effective air change rates are observed when vents are sized without reference to building airtightness, and significant energy penalties result for the leakier homes. This study evaluates the provision of passive through-wall ventilation as part of a retrofit programme and shows it to have a number of drawbacks that may impact on the health of the building and its occupants and ultimately be at odds with the aims of achieving energy efficiency in the residential sector.