1,693 research outputs found

    Carbon capture in the cement industry: technologies, progress, and retrofitting

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    Several different carbon-capture technologies have been proposed for use in the cement industry. This paper reviews their attributes, the progress that has been made toward their commercialization, and the major challenges facing their retrofitting to existing cement plants. A technology readiness level (TRL) scale for carbon capture in the cement industry is developed. For application at cement plants, partial oxy-fuel combustion, amine scrubbing, and calcium looping are the most developed (TRL 6 being the pilot system demonstrated in relevant environment), followed by direct capture (TRL 4–5 being the component and system validation at lab-scale in a relevant environment) and full oxy-fuel combustion (TRL 4 being the component and system validation at lab-scale in a lab environment). Our review suggests that advancing to TRL 7 (demonstration in plant environment) seems to be a challenge for the industry, representing a major step up from TRL 6. The important attributes that a cement plant must have to be “carbon-capture ready” for each capture technology selection is evaluated. Common requirements are space around the preheater and precalciner section, access to CO2 transport infrastructure, and a retrofittable preheater tower. Evidence from the electricity generation sector suggests that carbon capture readiness is not always cost-effective. The similar durations of cement-plant renovation and capture-plant construction suggests that synchronizing these two actions may save considerable time and money

    Real world hospital costs following stress echocardiography in the UK: a costing study from the EVAREST/BSE-NSTEP multi-centre study

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    Background - Stress echocardiography is widely used to detect coronary artery disease, but little evidence on downstream hospital costs in real-world practice is available. We examined how stress echocardiography accuracy and downstream hospital costs vary across NHS hospitals and identified key factors that affect costs to help inform future clinical planning and guidelines. Methods - Data on 7636 patients recruited from 31 NHS hospitals within the UK between 2014 and 2020 as part of EVAREST/BSE-NSTEP clinical study, were used. Data included all diagnostic tests, procedures, and hospital admissions for 12 months after a stress echocardiogram and were costed using the NHS national unit costs. A decision tree was built to illustrate the clinical pathway and estimate average downstream hospital costs. Multi-level regression analysis was performed to identify variation in accuracy and costs at both patient, procedural, and hospital level. Linear regression and extrapolation were used to estimate annual hospital cost-savings associated with increasing predictive accuracy at hospital and national level. Results – Stress echocardiography accuracy varied with patient, hospital and operator characteristics. Hypertension, presence of wall motion abnormalities andhigher number of hospital cardiology outpatient attendances annually reduced accuracy, adjusted odds ratio of 0.78 (95% CI: 0.65 to 0.93), 0.27 (95% CI: 0.15 to 0.48), 0.99 (95% CI: 0.98 to 0.99) respectively, whereas a prior myocardial infarction, angiotensin receptor blocker medication, and greater operator experience increased accuracy, adjusted odds ratio of 1.77 (95% CI: 1.34 to 2.33), 1.64 (95% CI: 1.22 to 2.22), and 1.06 (95% CI: 1.02 to 1.09) respectively. Average downstream costs were £646 per patient (SD 1796) with significant variation across hospitals. The average downstream costs between the 31 hospitals varied from £384-1730 per patient. False positive and false negative tests were associated with average downstream costs of £1446 (SD £601) and £4192 (SD 3332) respectively, driven by increased non-elective hospital admissions, adjusted odds ratio 2.48 (95% CI: 1.08 to 5.66), 21.06 (95% CI: 10.41 to 42.59) respectively. We estimated that an increase in accuracy by 1 percentage point could save the NHS in the UK £3.2 million annually. Conclusion – This study provides real-world evidence of downstream costs associated with stress echocardiography practice in the UK and estimates how improvements in accuracy could impact healthcare expenditure in the NHS. A real-world downstream costing approach could be adopted more widely in evaluation of imaging tests and interventions to reflect actual value for money and support realistic planning

    Global and regional left ventricular myocardial deformation measures by magnetic resonance feature tracking in healthy volunteers: comparison with tagging and relevance of gender

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    This work was funded by a grant from the Engineering and Physical Sciences Research Council (EP/G030693/1) and supported by the Oxford British Heart Foundation Centre of Research Excellence and the National Institute for Health Research Oxford Biomedical Research Centr

    Obese Subjects Show Sex-Specific Differences in Right Ventricular Hypertrophy

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    As right ventricular (RV) remodeling in obesity remains underinvestigated, and the impact of left ventricular (LV) diastolic dysfunction on RV hypertrophy is unknown, we aimed to investigate whether (1) sex-specific patterns of RV remodeling exist in obesity and (2) LV diastolic dysfunction in obesity is related to RV hypertrophy.Seven hundred thirty-nine subjects (women, n=345; men, n=394) without identifiable cardiovascular risk factors (body mass index [BMI], 15.3-59.2 kg/m2) underwent cardiovascular magnetic resonance (1.5 T) to measure RV mass (g), RV end-diastolic volume (mL), RV mass/volume ratio, and LV diastolic peak filling rate (mL/s). All subjects were normotensive (average, 119±11/73±8 mm Hg), normoglycaemic (4.8±0.5 mmol/L), and normocholesterolaemic (4.8±0.9 mmol/L) at the time of scanning. Across both sexes, there was a moderately strong positive correlation between BMI and RV mass (men, +0.8 g per BMI point increase; women, +1.0 g per BMI point increase; both P<0.001). Whereas women exhibited RV cavity dilatation (RV end-diastolic volume, +1.0 mL per BMI point increase; P<0.001), BMI was not correlated with RV end-diastolic volume in men (R=0.04; P=0.51). Concentric RV remodeling was present in both sexes, with RV mass/volume ratio being positively correlated to BMI (men, R=0.41; women, R=0.51; both P<0.001). Irrespective of sex, the LV peak filling rate was negatively correlated with both RV mass (men, R=-0.43; women, R=-0.44; both P<0.001) and RV mass/volume ratio (men, R=-0.37; women, R=-0.35; both P<0.001).A sex difference in RV remodeling exists in obesity. Whereas men exhibit concentric RV remodeling, women exhibit a mixed pattern of eccentric and concentric remodeling. Regardless of sex, reduced LV diastolic function is associated with concentric RV remodeling

    Neurohumoral and ambulatory haemodynamic adaptations following isometric exercise training in unmedicated hypertensive patients

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    Objective: Hypertension remains the leading modifiable risk factor for cardiovascular disease (CVD). Isometric exercise training (IET) has been shown to be a useful non-pharmacological intervention for reducing resting blood pressure (BP). This study aimed to measure alterations in office BP, ambulatory BP, cardiac autonomic modulation and inflammatory and vascular biomarkers following a programme of IET in unmedicated hypertensive patients. Methods: Twenty-four unmedicated stage 1 hypertensive patients (age 43.8±7.3 years; height, 178.1±7 cm; weight 89.7±12.8 kg) were randomly assigned in a cross-over study design, to 4-weeks of home based IET and control period, separated by a 3-week washout period. Office and Ambulatory BP, cardiac autonomic modulation, and inflammatory and vascular biomarkers were recorded pre and post IET and control periods. Results: Clinic and 24-hour ambulatory BP significantly reduced following IET by 12.4/6.2 mmHg and 11.8/5.6 mmHg in systolic/diastolic BP, respectively (p<0.001 for both), compared to the control. The BP adaptations were associated with a significant (p=0.018) reduction in the average real variability of 24-hour ambulatory BP following IET, compared to control. Cardiac autonomic modulation improved by 11% (p<0.001), baroreceptor reflex sensitivity improved by 47% (p<0.001), and interleukin-6 and asymmetric dimethylarginine reduced by 10% (p=0.022) and 19% (p=0.023), respectively, which differed significantly to the control period. Conclusion: This is the first evidence of durable BP reduction and wider CVD risk benefits of IET in a relevant patient population. Our findings support the role of IET as a safe and viable therapeutic and preventative intervention in the treatment of HTN

    p-Adic Models of Ultrametric Diffusion Constrained by Hierarchical Energy Landscapes

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    We demonstrate that p-adic analysis is a natural basis for the construction of a wide variety of the ultrametric diffusion models constrained by hierarchical energy landscapes. A general analytical description in terms of p-adic analysis is given for a class of models. Two exactly solvable examples, i.e. the ultrametric diffusion constraned by the linear energy landscape and the ultrametric diffusion with reaction sink, are considered. We show that such models can be applied to both the relaxation in complex systems and the rate processes coupled to rearrangenment of the complex surrounding.Comment: 14 pages, 6 eps figures, LaTeX 2.0

    A revised look at the effects of the Channel Model on molecular communication system

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    Molecular communications, where information is passed between the Transmitter (TX) and the Receiver (RX) via molecules is a promising area with vast potential applications. However, the infancy of the topic within the overall taxonomy of communications has meant that to date, several channel models are in press, each of which is applied under various constraints and/or assumptions. Amongst them is that the arrival of molecules in different time slots can be, or is, considered as independent events. In practice, this assumption is not accurate, as the molecules arriving in the previous slot reduce the possible number of molecules in the next slot and hence make them correlated. In this letter, we analyze a more realistic performance of a molecular communication assuming correlated events. The key result shown, is that the widely used model assuming independent events significantly overestimates the error rates in the channel. This result is thus critical to researchers who focus on energy use at the nano-scale, as the new analysis provides a more realistic prediction and therefore, less energy will be needed to attain a desired error rate, increasing system feasibility
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