139 research outputs found

    Influence of biochar composition and source material on catalytic performance : the carboxylation of glycerol with CO2 as a case study

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    The impact of the chemical and physical composition of biochar catalysts is demonstrated in the carboxylation of glycerol with carbon dioxide for the first time, using acetonitrile as a dehydrating agent. Biochars are an important emerging class of catalytic material that can readily be produced from low-value biomass residues; however, the impact of feedstock choice is often overlooked. The ash content of biochar from three different feedstocks is shown to be catalytically active for the production of glycerol carbonate and triacetin, whilst low-ash catalysts such as soft wood biochar and commercial activated charcoal are inactive. Following treatment with hydrochloric acid, yields of glycerol carbonate over ash were reduced by over 94%, and triacetin was no longer produced. This has been attributed to the loss of potassium content. Carbon content was shown to be catalytically active for the synthesis of diacetin, and graphitic carbon may be beneficial. Through the development of structure–performance relationships, biomass feedstocks with the most suitable properties can therefore be selected to produce biochars for specific catalytic applications. This would expand the range of reactions which can be effectively catalysed by these materials and enhance the development of a more circular and sustainable chemicals industry

    Application of Cow Manure Waste and Calcium Oxide Lime (CaO) on Growth and Yield of Cowpea Plant (Vigna Sinensis L.)

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    Introduction: The research was aimed to obtain an appropriate dose of cow manure waste, calcium oxide lime, and interactions in increasing the growth and yield of cowpea. Material and Methods: The research was conducted in Secanggang Village, Secanggang Subdistrict, Langkat District in June until September 2017. The research was conducted using the Randomized Block Design Factorial, the first factor (cow manure waste) dose of L0 = 0 ton.ha-1; L1 = 10 ton.ha-1; L2 = 20 ton.ha-1. The second factor (calcium oxide lime) dose of K0 = 0 ton.ha-1; K1 = 3 ton.ha-1; K2 = 6 ton.ha-1; and K3 = 9 ton.ha-1. Data were analyzed using the F and followed by DMRT at level 5% using IBM SPSS Statistics v.20 software. Results: The cow manure waste dosages of 10 until 20 ton.ha-1 significantly increased the plant height at 4 Weeks After Planting (WAP) and yield.plot-1 of cowpea ranged from 2.14 to 2.50% and 13.00 to 15.98%, respectively and the dose of 20 ton.ha-1 significantly increased the yield.sample-1 of 17.44% compared to untreated. The application of calcium oxide lime at the dose of 9 ton.ha-1 significantly increased the plant height of cowpea at 4 WAP of 2.46%, and the dose of 6 until 9 ton.ha-1 significantly increased the yield.sample-1 and yield.plot-1, however the highest was found in the dosage 6 ton.ha-1 of 13.51% and 20.16% compared to untreated. The interaction of cow manure waste with calcium oxide lime were not significant effect on growth and yield of cowpea

    A novel approach to human motion estimation with applications in human-robot safety

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    Assistive robotics has brought convenience especially to disabled and handicapped including the blinds. Mobile housekeeping robots such as floor cleaners are capable of local obstacle avoidance. However there is always a risk of hitting moving obstacles or blind human when they walk through the environment. In this article, a new decision mechanism is introduced for modelling path planning strategies adopted by blind travellers including wall-following, and taking shortcuts in indoor spaces e.g.; home, and office. A statistical path prediction method is used together with Fuzzy Cognitive Map FCM for prediction of entire paths from partial trajectories. Supplying knowledge from the presented model of spatial cognition and path planning to mobile robots can enhance their motion algorithms for better obstacle avoidance as well as safer service to users with visual impairment and blindness

    Combining left atrial appendage closure and catheter ablation for atrial fibrillation: 2-year outcomes from a multinational registry

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    AIMS: Clinical practice guidelines do not recommend discontinuation of long-term oral anticoagulation in patients with a high stroke risk after catheter ablation for atrial fibrillation (AF). Left atrial appendage closure (LAAC) with Watchman has emerged as an alternative to long-term anticoagulation for patients accepting of the procedural risks. We report on the long-term outcomes of combining catheter ablation procedures for AF and LAAC from multicentre registries. METHODS AND RESULTS: Data were pooled from two prospective, real-world

    Left atrial appendage closure with WATCHMAN in Asian patients: 2 year outcomes from the WASP registry

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    Background: Left atrial appendage closure is a non-pharmacological alternative for stroke prevention in high-risk non-valvular atrial fibrillation patients, but has not been widely studied in Asian patients. The prospective WASP registry assessed real-world outcomes for patients undergoing WATCHMAN implant in the Asia-Pacific region. Methods: Data were collected from consecutive patients across 9 centres. Major endpoints included procedural success, safety and long-term outcomes including occurrence of bleeding, stroke/transient ischaemic attack/systemic embolism and all-cause mortality. Results: Subjects (n = 201) had a mean age of 70.8 ± 9.4 years, high stroke risk (CHA2DS2-VASc: 3.9 ± 1.7), elevated bleeding risk (HAS-BLED: 2.1 ± 1.2) with 53% patients from Asian countries. Successful implantation occurred in 98.5% of patients; 7-day device/procedure-related SAE rate was 3.0%. After 2 years of follow-up, the rates of ischaemic stroke/TIA/SE and major bleeding were 1.9 and 2.2 per 100-PY, respectively, representing relative reductions of 77% and 49% versus expected rates per risk scores. The relative risk reductions versus expected rates were more pronounced in Asians vs. Non-Asians (89% vs 62%; 77% vs 14%). Other significant findings included larger mean LAA ostium diameter for Asians vs. Non-Asians (23.4 ± 4.1 mm vs. 21.2 ± 3.2 mm, p < 0.001) and hence requirement for larger median device size (27 mm for Asians, 24 mm for non-Asians [p < 0.0001]). Conclusion: Real-world experience of left atrial appendage closure with WATCHMAN has demonstrated low peri-procedural risk, and long-term efficacy for stroke and bleeding prevention in a primarily Asian cohort.Karen P. Phillips, Teguh Santoso, Prashanthan Sanders, Jeffrey Alison, Jason Leung Kwai Chan, Hui-Nam Pak, Mann Chandavimol, Kenneth M. Stein, Nicole Gordon, Omar Bin Razal

    Integration of VR with BIM to facilitate real-time creation of bill of quantities during the design phase:a proof of concept study

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    As time goes on and building practices change, procedures that at one point seemed indispensable can fall by the wayside. One such example is the bill of quantities (B/Q). Research into the extant literature attributes declining use of B/Qs to a multitude of reasons, such as its complexity and potentially drawn-out time to produce, non-traditional procurement systems growing in popularity and the challenge of using its information in a construction schedule. With these issues in mind, a combined process of Building Information Modelling (BIM), Virtual Reality (VR) and including the client in the design process has been proposed as a potential solution. Following a literature review and precedent study, an experiment was carried out using this new process to simulate a client’s design decisions on window and interior furnishings, specifically. Their choices made using VR automatically updated a B/Q Revit Schedule and allowed the client to have a firm grasp on the project costs. Not only did this process give the client more confidence in a pleasing final outcome, but the technology ensured an up-to-date, accurate and easily understood B/Q. Here lies great potential savings in cost, time and gives the B/Q a newfound importance in future construction processes. The research case presented in this paper was a stepping stone in exploring new opportunities offered by VR and BIM and how they could improve the reliability and accuracy of traditional procurement within construction, specifically within the B/Q document

    Combining Watchman left atrial appendage closure and catheter ablation for atrial fibrillation: Multicentre registry results of feasibility and safety during implant and 30 days follow-up

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    Aims Long-term results from catheter ablation therapy for atrial fibrillation (AF) remain uncertain and clinical practice guidelines recommend continuation of long-term oral anticoagulation in patients with a high stroke risk. Left atrial appendage closure (LAAC) with Watchman has emerged as an alternative to long-term anticoagulation for patients accepting of the procedural risks. We report on the initial results of combining catheter ablation procedures for AF and LAAC in a multicentre registry. Methods and results Data were pooled from two prospective, real-world Watchman LAAC registries running in parallel in Europe/Middle-East/Russia (EWOLUTION) and Asia/Australia (WASP) between 2013 and 2015. Of the 1140 patients, 139 subjects at 10 centres underwent a concomitant AF ablation and LAAC procedure. The mean CHA 2 DS 2 -VASc score was 3.4 ± 1.4 and HAS-BLED score 1.5 ± 0.9. Successful Watchman implantation was achieved in 100% of patients. The overall 30-day serious adverse event (SAE) rate was 8.7%, with the device and/or procedure-related SAE rate of 1.4%. One pericardial effusion required percutaneous drainage, but there were no strokes, device embolization, or deaths at 30 days. The 30-day bleeding SAE rate was 2.9% with 55% of patients prescribed NOAC and 38% taking warfarin post-procedure. Conclusion The outcomes from these international, multicentre registries support the feasibility and safety of performing combined procedures of ablation and Watchman LAAC for patients with non-valvular AF and high stroke risk. Further data are needed on long-term outcomes for the hybrid technique on all-cause stroke and mortality

    Robot education peers in a situated primary school study: personalisation promotes child learning

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    The benefit of social robots to support child learning in an educational context over an extended period of time is evaluated. Specifically, the effect of personalisation and adaptation of robot social behaviour is assessed. Two autonomous robots were embedded within two matched classrooms of a primary school for a continuous two week period without experimenter supervision to act as learning companions for the children for familiar and novel subjects. Results suggest that while children in both personalised and non-personalised conditions learned, there was increased child learning of a novel subject exhibited when interacting with a robot that personalised its behaviours, with indications that this benefit extended to other class-based performance. Additional evidence was obtained suggesting that there is increased acceptance of the personalised robot peer over a non-personalised version. These results provide the first evidence in support of peer-robot behavioural personalisation having a positive influence on learning when embedded in a learning environment for an extended period of time

    The impact of surgical delay on resectability of colorectal cancer: An international prospective cohort study

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    AIM: The SARS-CoV-2 pandemic has provided a unique opportunity to explore the impact of surgical delays on cancer resectability. This study aimed to compare resectability for colorectal cancer patients undergoing delayed versus non-delayed surgery. METHODS: This was an international prospective cohort study of consecutive colorectal cancer patients with a decision for curative surgery (January-April 2020). Surgical delay was defined as an operation taking place more than 4 weeks after treatment decision, in a patient who did not receive neoadjuvant therapy. A subgroup analysis explored the effects of delay in elective patients only. The impact of longer delays was explored in a sensitivity analysis. The primary outcome was complete resection, defined as curative resection with an R0 margin. RESULTS: Overall, 5453 patients from 304 hospitals in 47 countries were included, of whom 6.6% (358/5453) did not receive their planned operation. Of the 4304 operated patients without neoadjuvant therapy, 40.5% (1744/4304) were delayed beyond 4 weeks. Delayed patients were more likely to be older, men, more comorbid, have higher body mass index and have rectal cancer and early stage disease. Delayed patients had higher unadjusted rates of complete resection (93.7% vs. 91.9%, P = 0.032) and lower rates of emergency surgery (4.5% vs. 22.5%, P < 0.001). After adjustment, delay was not associated with a lower rate of complete resection (OR 1.18, 95% CI 0.90-1.55, P = 0.224), which was consistent in elective patients only (OR 0.94, 95% CI 0.69-1.27, P = 0.672). Longer delays were not associated with poorer outcomes. CONCLUSION: One in 15 colorectal cancer patients did not receive their planned operation during the first wave of COVID-19. Surgical delay did not appear to compromise resectability, raising the hypothesis that any reduction in long-term survival attributable to delays is likely to be due to micro-metastatic disease
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