1,670 research outputs found
Ammonia removal in anaerobic digestion by biogas stripping: an evaluation of process alternatives using a first order rate model based on experimental findings
The feasibility of biogas stripping to remove ammonia in the anaerobic digestion of source segregated food waste was investigated. It was found in batch experiments that ammonia could be removed from digestate and that the removal followed 1st order kinetics with respect to total ammonia nitrogen concentration. Increasing temperature, biogas flow rate and initial pH all increased removal rates. Using kinetic data gathered in these experiments allowed the integration of ammonia stripping with an anaerobic digestion plant to be modelled for different configurations. Four scenarios were identified: post digestion, in situ, side-stream and pre-digestion ammonia removal relating to where in the process the ammonia stripping was performed. The modelling showed that in situ ammonia removal may be best able to reduce in-digester ammonia concentrations over a wide range of organic loading rates whereas pre-digestion showed most promise in terms of application due to the flexibility to control each part of the process separately. Further experimental work is required into these scenarios to confirm their viability
British architectural polychromy: 1840-1870
In 1984, among the proposals for the redecoration of the British Museum was a plan
to reinstate the decorative scheme for the Entrance Hall created in 1847 by Sydney
Smirke. The controversy that ensued is the departure point for this thesis. Sydney
Smirke's decorative scheme proved to be much more than simple embellishment of
the space. It was a polychromatic scheme based on ancient Greek motifs and colours
and their archaeological manner of use manifested the period's preoccupation with
architectural historicism, and also final recognition that the Greeks had used bright
colours on their buildings and sculpture.
This thesis examines the architectural context of Smirke's scheme, and the
development of architectural polychromy as a prominent feature of British
architecture between 1840 and 1870. Although previous historical studies have been
made of colour in the work of individual architects, and of the relation between the
practice of polychromy and architectural thought (especially that of John Ruskin),
there exists no comprehensive study of the practice of polychromy in mid-nineteenth
century Britain. In particular, existing studies have not sufficiently stressed the great
diversity of the sources for British polychromy. Part of the purpose of this thesis is to
show that the development of polychromy by British architects was indebted not
only to medieval sources, but also to antiquity, and to Islamic sources; and
furthermore to show that the emergence of an architectural discourse about
polychromy emerged not only out of the study of ecclesiology, and the writings of
John Ruskin, but also from classical archaeology, and from contemporary European
architectural thought. Of the various figures whose work is studied, Owen Jones
emerges as the person who more than any other provided a connection between these
diverse sources and ideas
Three point SUSY Ward identities without Ghosts
We utilise a non-local gauge transform which renders the entire action of
SUSY QED invariant and respects the SUSY algebra modulo the gauge-fixing
condition, to derive two- and three-point ghost-free SUSY Ward identities in
SUSY QED. We use the cluster decomposition principle to find the Green's
function Ward identities and then takes linear combinations of the latter to
derive identities for the proper functions.Comment: 20 pages, no figures, typos correcte
Developing a tradition of scholarship : the emergence and evolution of the AHRD-sponsored journals
The Problem
Research and theory are the lifeblood of academic disciplines along with the peer-reviewed journals that disseminate such scholarship. Journals become critical repositories that capture the histories and evolution of such disciplines, and their scholarly contributions generate new knowledge that can stimulate further research and improve practice. The Academy of Human Resource Development (AHRD) sponsors four peer-reviewed journals that have contributed to the birth and evolution of the discipline of human resource development (HRD). Yet, little is known about how they came into being, how they have evolved, and what their impact has been within the field of HRD.
The Solution
This article captures the histories of the emergence and evolution of the four refereed journals sponsored by the AHRD through the unique voices of current and recent past editors of these journals. It then considers common themes of scholarship across the four journals that have helped to shape HRD.
The Stakeholders
Students, researchers, and scholar-practitioners in the field of HRD and related fields who are interested in learning more about the histories of the journals sponsored by the AHRD, along with their contributions to the scholarship in HRD, will benefit from reading this article
Correction to: Shoulder pain prevalence by age and within occupational groups: A systematic review
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Rapid conformational analysis of semi-flexible liquid crystals.
We present an approach for rapid conformational analysis of semi-flexible liquid crystals. We use a simple graphical user interface (GUI) tool that leverages rules-based methods for efficient generation of bend-angle distributions, offering a significant improvement over traditional single-conformer analysis. Our methods demonstrated proficiency in approximating molecular shapes comparable to those obtained from molecular dynamics (MD) simulations, albeit with notable deviations in the under sampling of hairpin conformations and oversampling of extended configurations. Re-evaluation of existing data revealed an apparent weak correlation between NTB transition temperatures and bend angles, underscoring the complexity of molecular shapes beyond mere geometry. Furthermore, we integrated this conformational analysis into a pipeline of algorithmic molecular design, utilising a fragment-based genetic algorithm to generate novel cyanobiphenyl-containing materials. This integration opens new avenues for the exploration of liquid crystalline materials, particularly in systems where systematic conformer searches are impractical, such as large oligomeric systems. Our findings highlight the potential and growing importance of computational approaches in accelerating the design and synthesis of next-generation liquid crystalline materials
Extension parallel to the rift zone during segmented fault growth: application to the evolution of the NE Atlantic
The mechanical interaction of propagating normal faults is known to influence the linkage geometry of first-order faults, and the development of second-order faults and fractures, which transfer displacement within relay zones. Here we use natural examples of growth faults from two active volcanic rift zones (Koa`e, island of Hawai`i, and Krafla, northern Iceland) to illustrate the importance of horizontal-plane extension (heave) gradients, and associated vertical axis rotations, in evolving continental rift systems. Second-order extension and extensional-shear faults within the relay zones variably resolve components of regional extension, and components of extension and/or shortening parallel to the rift zone, to accommodate the inherently three-dimensional (3-D) strains associated with relay zone development and rotation. Such a configuration involves volume increase, which is accommodated at the surface by open fractures; in the subsurface this may be accommodated by veins or dikes oriented obliquely and normal to the rift axis. To consider the scalability of the effects of relay zone rotations, we compare the geometry and kinematics of fault and fracture sets in the Koa`e and Krafla rift zones with data from exhumed contemporaneous fault and dike systems developed within a > 5×104 km2 relay system that developed during formation of the NE Atlantic margins. Based on the findings presented here we propose a new conceptual model for the evolution of segmented continental rift basins on the NE Atlantic margins
Adsorption of the prototypical organic corrosion inhibitor benzotriazole on the Cu(100) surface
The interaction of benzotriazole (BTAH) with Cu(100) has been studied as a function of BTAH exposure in a joint experimental and theoretical effort. Scanning tunnelling microscopy (STM), X-ray photoelectron spectroscopy (XPS), high resolution electron energy loss spectroscopy (HREELS) and density functional theory (DFT) calculations have been combined to elucidate the structural and chemical characteristics of this system. BTAH is found to deprotonate upon adsorption on the copper surface and to adopt an orientation that depends on the molecular coverage. Benzotriazolate (BTA) species initially lie with their planes parallel to the substrate but, at a higher molecular coverage, a transition occurs to an upright adsorption geometry. Upon increasing the BTAH exposure, different phases of vertically aligned BTAs are observed with increasing molecular densities until a final, self-limiting monolayer is developed. Both theory and experiment agree in identifying CuBTA and Cu(BTA)2 metal-organic complexes as the fundamental building blocks of this monolayer. This work shows several similarities with the results of previous studies on the interaction of benzotriazole with other low Miller index copper surfaces, thereby ideally completing and concluding them. The overall emerging picture constitutes an important starting point for understanding the mechanism for protection of copper from corrosion
Loading a vapor cell magneto-optic trap using light-induced atom desorption
Low intensity white light was used to increase the loading rate of Rb
atoms into a vapor cell magneto-optic trap by inducing non-thermal desorption
of Rb atoms from the stainless steel walls of the vapor cell. An increased Rb
partial pressure reached a new equilibrium value in less than 10 seconds after
switching on the broadband light source. After the source was turned off, the
partial pressure returned to its previous value in times as short as 10
seconds.Comment: 7 pages, 6 figure
A cross-sectional examination of the early-onset hypertensive disorders of pregnancy and industrial emissions of toxic metals using Kentucky birth records, 2008–2017
This cross-sectional study assessed geospatial patterns of early-onset hypertensive disorders of pregnancy (eHDP) in primiparous mothers and exposure to industrial emissions using geocoded residential information from Kentucky live (N = 210,804) and still (N = 1,247) birth records (2008–2017) and census block group estimates of aerosol concentrations of arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb), mercury (Hg), selenium (Se), and zinc (Zi) from the Risk Screening Environmental Indicators (RSEI) model. A latent class analysis allowed for the identification of four district exposure classes—As, Cd, and Pb (12.6%); Se and Zi (21.4%); Pb and Cr (8%); and low or no exposures (57.9%). Women classified as having a high probability of exposure to both Pb and Cr had a statistically significantly greater prevalence of eHDP after adjusting for demographic factors (aPR = 1.22, 95% CI: 1.04, 1.44) relative to those with low or no exposure. Our findings contribute to the emerging literature on the association of metal exposures with pregnancy outcomes
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