Oxidative desulfurization of dibenzothiophene with tert-butyl peroxide in a carbon nanotube supported corona discharge microreactor

Sulfur content in fuel is an increasingly important environmental concern. A commonly used method for the removal of sulfur bearing species from fuel is through hydrodesulphurization. However, due to the implementation of Ultra-Low Diesel Sulfur (ULDS), deeper desulphurization techniques must be explored. In this study, a single phase oxidative desulphurization microreactor is crafted for this purpose. The proposed microreactor is built around the concept of corona discharge. The corona is created through a significant potential difference between a carbon nanotube supported emitter electrode and a stainless steel collector electrode. The current that passes through the two electrodes acts as a catalytic agent for the oxidation of the sulfur bearing species. Dibenzothiophene and tert-butyl peroxide are mixed with decane into two separate feed streams. The two feed streams are sent through a micromixer and continue into the reactor. The reactor system is activated and current flows within the reaction volume between the two electrodes. The proposed reaction mechanism is similar to that of the photooxidation of dibenzothiophene in which the peroxide is cleaved by the electrical energy and subsequently reacts with the sulfur to form its oxides, sulfoxides and sulfones, respectively. Due to the high polarity of these products, they are easily extracted from the fuel stream. Experiments testing the capabilities of the proposed reactor include varying the applied current to the reaction volume, inlet concentrations of both the fuel and oxidant streams, the reactor volume residence time, the post-reactor volume residence time, and the effect of aging upon the oxidant stream. This proposed microreactor was successfully crafted and the corona successfully discharged between the emitter and collector electrodes. Testing of the reactor's capabilities suggest that the proposed oxidation mechanism is not strictly duplicated within this microreactor system. For this first generation reactor system, a maximum conversion of 68% of dibenzothiophene to its sulfoxide and sulfone has been found. Dissolved oxygen in decane was also found to be a sufficient oxidant source to initiate the oxidative reaction and has been shown to continue to be an oxidant source even in the presence of peroxide

Detailed analysis of the hydrogen sulfide production step in a sulfur-sulfur thermochemical water splitting cycle

The production of hydrogen has been one of the most heavily studied, energy related fields over the past half century, yet few methods are commercially or economically viable and none are currently sustainable. Of those aiming at the sustainable production of hydrogen using renewable resources, perhaps the most widely studied are those attempting to thermochemically split water via various chemical intermediates. These provide an attractive conceptual alternative to other methods due to lower energy input requirements and to the production of the targeted hydrogen and oxygen in separate reaction steps. One of the most widely studied thermochemical cycles is the Sulfur-Iodine cycle, the development of which has recently slowed due to the difficulty in the separation of hydrogen iodine from a hydrogen iodide-iodine-water azeotrope, material compatibility issues, and the perceived need use large amounts of iodine in the process. A modification of the Sulfur-Iodine thermochemical cycle that attempts to avoid those issues along with mitigating the need to process large amounts of water in the cycle was developed, in a cycle we describe as the Sulfur-Sulfur cycle. This new thermochemical cycle can be summarized by the reaction sequence shown below. [see abstract for chemical reactions] Previous work in our group demonstrated the viability of implementing the cycle's low temperature reactions (the first reaction pair, which we call the Bunsen reaction and the Hydrogen Sulfide Production (HSP) reactions) in ionic liquids, which removes the need to process large amounts of water and iodine in the reaction sequence, and minimizes the material compatibility issues, and also demonstrated the feasibility of stream reforming hydrogen sulfide. The present work focuses on an exergetic analysis of the Sulfur-Sulfur cycle, the careful determination of reaction kinetics for the HSP reaction, and developing a model of the kinetics of the low temperature reactions. The exergetic analysis was carried out based on the published thermochemical parameters for the species involved. The analysis showed that the maximum theoretical exergetic efficiency of the Sulfur-Sulfur cycle is nearly 70% with a strong dependence on the reaction temperature of the low temperature reactions. The kinetics of the Bunsen and HSP were investigated through iodine colorimetery and the effect of water was determined. This kinetic data was used for the development of a predictive kinetic model that could accurately monitor the progression of iodine through the reaction system. The work showed that the Bunsen reaction is very fast with an activation energy (E[subscript aB]) of 92.83 kJ/mol and a pre-exponential factor (k₀) of 7.65E+14 min⁻¹, while for the HSP reaction, they were determined to be 117.09 kJ/mole and 7.73E+16 min⁻¹. Integration of these two reactions into a single differential model based on iodine concentration fit the experimental profile extremely well The effect of including a Lewis base other than water in the reaction mixture yielded promising results that warrant future development. Specifically, the rates of both the Bunsen and HSP reactions increased with an increase in the pK[subscript b] of the added Lewis base. A local protocol to recycle the ionic liquid, enabling it to be reused in new experiments, was successfully developed. When the recycled ionic liquid is employed, effects similar to those found through the inclusion of the Lewis base were observed, suggesting that a decomposition product remains in the recycled ionic liquid. This effect could be minimized by acid washing the recycled ionic liquid prior to use

3D modelling of geological and anthropogenic deposits at the World Heritage Site of Bryggen in Bergen, Norway

The landscape of many historic cities and the character of their shallow subsurface environments are defined by a legacy of interaction between anthropogenic and geological processes. Anthropogenic deposits and excavations result from processes ranging from archaeological activities to modern urban development. Hence, in heritage cities, any geological investigation should acknowledge the role of past and ongoing human activities, while any archaeological investigation should be conducted with geological processes in mind. In this paper it is shown that 3D geological and anthropogenic models at different scales can provide a holistic system for the management of the subsurface. It provides a framework for the integration of other spatial and processmodels to help assess the preservationpotential for buried heritage. Such an integrated framework model is thus contributing to a decision support system for sustainable urban (re)development and regeneration in cities, while preserving cultural heritage. A collaborative approach is proposed to enhance research and implementation of combined geological and archaeological modelling for sustainable land use planning and heritage preservation, using York and Bryggen as prime examples. This paper presents the status of 3D framework modelling at Bryggen in Norway as an example

A pragmatic cognitive model for the interpretation of verbal–visual communication in television news programmes

The combination of the verbal and the visual track in television news discourse poses a considerable analytical challenge. In the viewers’ minds the co-habitation of these two semiotic channels triggers a complex network of inferential processes, based on expectations of coherence and relevance, with which they make sense of the representation of the world offered in the news. Through the analysis of a number of news items, this article considers the cognitive processes which viewers may activate when extracting meaning from the multimedial messages contained in television news. The analysis of news items from two British television networks offered by the authors traces the possible meanings that, it is assumed, become available to a potential, ‘idealised’ or ‘implied’ viewer, who accesses the information with some social and cultural knowledge of contemporary Britain. Building on existing studies, the article proposes a model for the classification of verbal–visual relations

The Clacton Spear: the last one hundred years

In 1911 an eminent amateur prehistorian pulled the broken end of a pointed wooden shaft from Palaeolithic-age sediments at a seaside town in Essex. This artefact, still the earliest worked wood to be discovered in the world, became known as the Clacton Spear. Over the past 100 years it has variously been interpreted as a projectile weapon, a stave, a digging stick, a snow probe, a lance, a game stake and a prod to ward off rival scavengers. These perspectives have followed academic fashions, as the popular views of early hominins have altered. Since discovery the Clacton spear has also been replicated twice, has undergone physical transformations due to preservation treatments, and has featured in two public exhibitions. Within this article the changing context of the spear, its parallels, and all previous conservation treatments and their impacts are assessed.© 2015 Royal Archaeological Institute. This is an Accepted Manuscript of an article published by Taylor & Francis in The Archaeological Journal on 3rd March 2015, available online: http://www.tandfonline.com/doi.org/10.1080/00665983.2015.1008839.The attached document is the author(’s’) final accepted/submitted version of the journal article. You are advised to consult the publisher’s version if you wish to cite from it

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

Background: The EMPA KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population. Methods: EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110. Findings: Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5–2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62–0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16–1·59), representing a 50% (42–58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1). Interpretation: In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease. Funding: Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council

Re-imagining human rights photography: Ariella Azoulays intervention

Gormley and Allan focus on several pertinent theoretical contributions made by Ariella Azoulay that invite a radical rethinking of familiar assumptions regarding human rights photography. Having established a conceptual basis, they proceed to analyse several examples of photojournalists attempting to ‘activate’ viewers by inviting them to co-create photographic narratives via methods of hypertext and online archival interaction, and of International Non Governmental Organisations (INGOs) working to create projects which ‘speak’ to viewers by involving the children they seek to represent in the production of photography. It is argued that in taking up Azoulay’s call to rethink public relationships to human rights imagery, these projects represent progressive steps towards addressing the multifarious inequalities at stake. At the same time, however, realising this potential depends on making good the promise of rendering visible the normative ideals of human rights

Urolitíase: estudo comparativo em bovinos Guzerá oriundos de propriedades com e sem o problema

Diversos fatores podem contribuir para a formação de cálculos urinários, dentre estes, o desequilíbrio nutricional e a dureza da água consumida pelos ruminantes. O objetivo deste estudo foi identificar as características de propriedades que predispõem à urolitíase, através da avaliação da água, da dieta e determinações séricas e urinárias de cálcio, fósforo, magnésio, cloretos, sódio, potássio, cálculo da excreção fracionada (EF) dos eletrólitos, e da creatinina, proteína total, albumina e globulinas séricas. Foram colhidas amostras de sangue e urina de bovinos, Guzerá, criados semi intensivamente, distribuídos por dois grupos. O primeiro denominado grupo urolitíase (Gu), composto de animais com histórico, sinais clínicos e confirmação ultrassonográfica que apresentavam urolitíase; o segundo: grupo controle (Gc), sem histórico, nem sintomas da doença. Os bovinos do grupo urolitíase consumiam água com dureza total na concentração de 166,0mg CaCO3/L. A dieta dos animais do Gu apresentava maior concentração de fósforo e relação Ca:P inadequada. Os teores de fósforo sérico e urinário dos animais do Gu foram maiores do que os do Gc, assim como a concentração sérica de magnésio (p0,05), mas houve diminuição significativa nas EFs de magnésio, cloretos e de potássio do grupo urolitíase (p<0,05). A união destes fatores contribuiu para a ocorrência da urolitíase, sendo dureza total da água e a alta concentração de fósforo na dieta os principais fatores na gênese dos cálculos em bovinos

A(1,3) strain factors in the hydrobromination of cyclohexenecarboxylic acid

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33503/1/0000909.pd