60419 research outputs found
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Tamper-proofing Video with Hierarchical Attention Autoencoder Hashing on Blockchain
No full textWe present ARCHANGEL; a novel distributed
ledger based system for assuring the long-term integrity of digital video archives. First, we introduce a novel deep network architecture using a hierarchical attention autoencoder (HAAE) to compute temporal content hashes (TCHs) from minutes or hourlong audio-visual streams. Our TCHs are sensitive to accidental or malicious content modification (tampering). The focus of our
self-supervised HAAE is to guard against content modification such as frame truncation or corruption but ensure invariance against format shift (i.e. codec change). This is necessary due to the curatorial requirement for archives to format shift video
over time to ensure future accessibility. Second, we describe how
the TCHs (and the models used to derive them) are secured
via a proof-of-authority blockchain distributed across multiple independent archives.We report on the efficacy of ARCHANGEL within the context of a trial deployment in which the national
government archives of the United Kingdom, United States of
America, Estonia, Australia and Norway participated
Assessment of suspended growth biological process for treatment and reuse of mixed wastewater for irrigation of edible crops under hydroponic conditions
No full textDue to the increasing freshwater deterioration and demand for irrigation, there is pressing need to reclaim and reuse wastewater for agricultural operations. While this practice is gaining significant traction in developed world, it is quite rare in most developing countries with inadequate or no functional sewerage facilities and treatment systems at both municipal and industrial levels occasioned by high investment and operational costs. Consequently, wastewaters generated are in complex heterogenous mix of industrial, domestic, municipal and agricultural runoff wastewater. Biological technologies which utilize the expertise of microorganisms are considered robust, efficient and economically attractive for treatment of wide range of wastewaters and they have high suitability in developing countries. This work therefore assessed the potential of suspended growth biological process (SGBP) for reclamation and reuse of mixed wastewater composed a mixture of domestic effluent, pharmaceutical, textile, petroleum discharges and agricultural runoff for irrigation of edible crops (lettuce and beets) with plants phenological parameters as measuring indicators. The germination and phenological characteristics of crops were studied in a hydroponic unit under four irrigation regimes: tap water as control, mixed wastewater, SGBP treated wastewater, and tap water mixed with nutrient solution as upper control, for a duration of 45-d. The results proved that the SGBP treated wastewater had no negative impact on germination responses of the seed crops. However, residual recalcitrant compounds caused early stunted growth in plant root systems with resultant limited access to nutrients. Consequently, plant vegetative growth and phenological development as well as chlorophyll production were reduced. In comparison to nutrients supplemented solution, nutrients deficiency and imbalance in treated wastewater contributed to the poor development in irrigated plants. The outcomes of seed germination and plant growth experiments show a positive indication for reuse of mixed wastewater in agriculture. However, there is need for further research to explore the long-term benefits and limitations of reusing such treated wastewater
Enhanced air emission inventory for LCA of Kuwait Crude Oils
No full textLife cycle Assessments (LCAs) of crude oil derived products such as fuels, petrochemicals and polymers benefit from robust inventories of emissions and consumptions of the specific ways in which the crude oil can be extracted and processed. It is known that there is variation of up to 30% or more in the Greenhouse gas (GHG) ‘footprint’ of different crude oils depending upon the different crude types, production systems, geographic location etc. It is also known that in a number of comparative LCA analyses between petrochemical products and bio-based alternatives there can be rather small differences (e.g. 10 – 20%) in the GHG emissions or other environmental impacts. The large potential range in emissions profile per unit of crude oil and the sometimes-small margin of difference between crude-oil based products and alternatives suggests that the specific route of crude production (and processing) will be an important factor in decision-making and policy centred on environmental criteria. The research in this thesis was conducted to examine the site-specific air emission data, with emphasis on VOCs, for crude oil production and how this could affect the results of LCAs of petrochemical products in comparison with the use of generic LCA database data to characterize the environmental profiles of such products.
Company specific air emission data was collected from an upstream crude oil & gas company in Kuwait. The data collected was company available modelled data and new field measurements collected via the use of a mobile laboratory. This emission data was converted to specific substance emission values via Gaussian plume modelling and relating it to crude oil flows in the upstream facilities. Thereby new, specific LCI datasets for the air emissions of Kuwaiti crude oil were developed and deployed in LCAs to assess their effects on the environmental profiles of such crude oil and its end products. These LCAs demonstrated considerable heterogeneity in aspects of the environmental profile of the crude oils and example downstream end products driven by the specific LCI datasets for the various production systems examined
Prevalence of pulmonary nodules suggestive of metastasis at presentation in dogs referred for treatment of cutaneous and subcutaneous soft tissue sarcomas: 146 cases (2014-2018).
No full textObjective: The aim of this study was to investigate the prevalence of pulmonary nodules at presentation in cases of soft tissue sarcoma (STS) in dogs with no previous thoracic imaging.
Animals: Client-owned dogs with a histologic diagnosis of STS.
Procedures: Dogs were retrospectively included in this study if the first thoracic imaging performed was at the time of presentation to our referral center. De novo and recurrent tumors were included, and information regarding tumor grade, history (primary mass vs scar vs recurrence), duration, location and size was also collected.
Results: One hundred and forty-six dogs were included. Routine staging was performed with computed tomography (131 dogs, 89.7%) or 3-view thoracic radiographs (15 dogs, 10.3%). STS were grade 1 in 55.5% of dogs, grade 2 in 27.4% and grade 3 in 17.1%. Pulmonary nodules suggestive of metastasis were present in 11.7% of cases overall and in 6.5%, 5.6% and 37.5% of grade 1, grade 2 and grade 3 STS cases, respectively. Tumor grade (low/intermediate versus high) and tumor duration ( 3 months) were significantly associated with presence of pulmonary nodules at presentation.
Conclusions and Clinical Relevance: This is the first large study reporting prevalence of pulmonary nodules at presentation in dogs with STS having had no previous thoracic imaging. The prevalence of pulmonary nodules suggestive of metastasis at presentation is low (<7%) in grade 1 and grade 2 canine STS
Julie Wallace Award Lecture 2019: Vitamin D deficiency in western dwelling South Asian populations: an unrecognised epidemic
No full textVitamin D deficiency (25-hydroxyvitamin D; (OH)D) is at epidemic proportions in western 20 dwelling South Asian populations, including severe deficiency (<12.5 nmol/L) in 27-60 % of individuals, depending on season. This paper aimed to review the literature concerning vitamin D concentrations in this population group. Research from the UK and Europe suggests a high prevalence of South Asians with 25(OH)D concentration <25nmol/L, with most having a 25(OH)D concentration <50nmol/L. In Canada, South Asians appear to have a slightly higher 25(OH)D concentration. There are few studies from the United States, South Africa and Australasia. Reasons for vitamin D deficiency include low vitamin D intake, relatively high adiposity, sun exposure avoidance and wearing of a covered dress style for cultural reasons. Possible health effects of deficiency include bone diseases such as rickets and hypocalcaemia in children and osteomalacia in adults. Vitamin D deficiency may also increase the risk of other chronic diseases. Increased fortification of food items relevant to South Asian groups (e.g. chapatti flour), as well as increased use of vitamin D supplements may help reduce this epidemic. Introducing culturally acceptable ways of increasing skin exposure to the sun in South Asian women may also be beneficial but further research is needed to assess the effectiveness of different approaches. There may be a need for a South Asian specific vitamin D dietary intake guideline in western countries. To conclude, vitamin D deficiency is epidemic in South Asians living in western countries and there is a clear need for urgent public health action
A selective and easily recyclable dimer based on a calix[4]pyrrole derivative for the removal of mercury(ii) from water
No full textA recyclable mercury (II) selective dimer based on a calix[4]pyrrole derivative has been synthesised
and characterised by Mass and FT- IR Spectrometry, Scanning Electron Microscopy (SEM) and
Energy Dispersive X-ray (EDX). Information regarding the ability of the dimer to interact with metal
cations was obtained from FTIR and SEM-EDX analyses. A striking feature of micrographs of the
loaded dimer is the change of morphology with the cation. Based on these results, optimal conditions
for removing cations from water were assessed under different experimental conditions. Results
obtained demonstrate that the removal process is fast. Capacity values and selectivity factors show that
the dimer is selective for Hg(II) in one and in multiple component metal solutions relative to other
cations. Single-ion transfer Gibbs energies from water to a solvent containing common functionalities to
those of the dimer were used to assess the counter-ion effect on the removal process. Agreement is
found between these data and energy calculations derived from Molecular Simulation studies. Studies
on polluted water in the presence of normal water components in addition to toxic metal cations are
reported. Further experimental work on wastewater from the mining industry is in progress
Influence of temperature and other system parameters on microbial fuel cell performance: numerical and experimental investigation
No full textThis study presents a steady state, two dimensional mathematical model of microbial fuel cells (MFCs) developed by coupling mass, charge and energy balance with the bioelectrochemical reactions. The model parameters are estimated and validated using experimental results obtained from �ve aircathode MFCs operated at different temperatures. Model analysis correctly
predicts the nonlinear performance trend of MFCs with temperatures ranging between 20 oC - 40 oC. The two dimensional distribution allows the computation
of local current density and reaction rates in the bio�lm, helping to correctly capture the interdependence of system variables and predict the
drop in power density at higher temperatures. Model applicability for parametric
analysis and process optimization is further highlighted by studying the effect of electrode spacing and ionic strength on MFC performance
Applications of the Experience Sampling Method: A Research Agenda for Hospitality Management
No full textPurpose – This study aims to provide researchers in hospitality management with a comprehensive understanding of the experience sampling method (ESM) and to engage them in the use of ESM in their future research. With this critical discussion of the advantages and challenges of the method, researchers can apply it appropriately to deepen and broaden their research findings.
Design/methodology/approach – This study chooses an empirical example in the context of hotel employees’ surface acting, tiredness and sleep quality to illustrate the application of ESM. Based on the example, this paper conducts two-level modeling in Mplus, including a cross-level mediation analysis and mean centering.
Findings – This paper demonstrates the applicability and usefulness of ESM for hospitality research and provides a detailed demonstration of how to use the statistical program Mplus to analyze ESM data. With this paper, researchers will be able to consider how to engage ESM in their future studies.
Originality/value – This paper is among the first to provide a hands-on demonstration of ESM to hospitality researchers. We call for more research in hospitality management to use ESM to answer complex and pressing research questions
A comparison between two modal domain methods for personal audio reproduction
No full textPersonal audio provides private and personalized listening experiences by generating sound zones in a shared space with minimal interference between zones. One challenge of the design is to achieve the best performance with a limited number of microphones and loudspeakers. In this paper, two modal domain methods for personal audio
reproduction are compared. One is the spatial harmonic decomposition (SHD) based method and the other is the
singular value decomposition (SVD) based method. It is demonstrated that the SVD based method provides a more
efficient modal domain decomposition than the SHD method for 2.5 dimensional personal audio design. Simulation
results show that the SVD based method outperforms the SHD one by up to 10 dB in terms of acoustic contrast and
up to 17 dB in terms of reproduction error for a compact arc array with five loudspeakers, while requiring fewer
microphones around the zone boundaries. The SVD based method retains the inherent efficiency of optimizing in a
modal domain while avoiding the inherent geometric limitations of using SHD basis functions. Thus, this approach is advantageous for applications with flexible system geometries and a small number of loudspeakers and
microphones
Emissions to liquid fuels: Development of advanced heterogeneous catalysts for CO2 valorisation
No full textCO2 utilisation is becoming an appealing topic in catalysis science due to the urgent need to deal with greenhouse gases (GHG) emissions. Herein, the dry reforming of methane (DRM) represents a viable route to convert CO2 and CH4 (two of the major GHG) into syngas, a highly valuable intermediate in chemical synthesis. Nickel-based catalysts are economically viable materials for this reaction, however they show inevitable signs of deactivation mainly caused by the agglomeration of the active phase and carbon deposition on the surface of the catalyst. In this work, stabilisation of Ni in a pyrochlore-perovskite structure is reported as a viable method to prevent fast deactivation. Substitution of Zirconium by Ni at various loadings in the lanthanum zirconate pyrochlore La2Zr2O7 is investigated in terms of reactant conversions under various reaction conditions. Crystallographic analysis of the catalysts showed the formation of phases corresponding to the pyrochlore structure La2Zr2-xNixO7-δ and an additional La2NiZrO6 perovskite phase at high Ni loadings. The pyrochlore mixed oxide shows high basicity and surface oxygen availability, leading to a material with high CO2 activation potential. In particular, the formation of lanthanum oxycarbonate is occurring upon CO2 activation. The best formulated catalyst shows excellent activity for various reforming reactions at temperatures as low as 600 °C and displays great stability over 350 hours of continuous dry operation. Versatility in feed ratio and syngas production was demonstrated. Carbon formation although inevitable, is limited using this formulation strategy. The presence of nanosized Ni particles contributes to the excellent performance of the catalyst. Exsolution of Ni from the host lattice is believed to occur upon activation pre-treatment of the catalyst and leads to small, well dispersed and highly active Ni clusters. Overall, this work showcases an appealing strategy to design economically viable advanced catalysts for chemical CO2 recycling via reforming reactions
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