97 research outputs found

    Moisture and Estimation of Indoor Moisture Generation Rate

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    Modelling and Analysing Time-Dependent Health Outcomes

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    Towards Integration of Energy Storage Systems for Carbon Neutral Buildings : A Review of Multi-Criteria Decision Making Approaches

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    Building sector consumes about 40% of the global energy consumption and emits over 30% of the global energy-related CO2 emissions. It is one of the most resource-intensive sectors and the main contributor of the environmental emissions. Additionally, the amount of greenhouse gas emissions is increasing remarkably due to the rapid growth in urbanization. Distributed energy resources (DERs) offer opportunities to support the deployment of large shares of renewable energy sources (RES) in order to meet the sustainability goals of reducing carbon emissions and increasing building resilience. DERs consist primarily of energy generation and energy storage systems (ESS) which are located near to the end-users of buildings, allowing easily integration of RES and realization of carbon neutrality. However, widespread adoption of renewable energy is challenging because of its intermittent nature. Energy supply does not satisfy with the demand, back-up supply from ESS is therefore required to solve the problems. ESS are of great importance for balancing supply and demand mismatches and offering the opportunity to replace fossil fuels with large shares of renewable penetration on DERs to eventually achieve zero-carbon emissions in buildings. Due to numerous factors that influence ESS, selection of the suitable energy storage technologies for specific building applications presents a challenge. In the literature, different criteria have been suggested to contrast ESS’ strengths and weaknesses for different applications. Methodologically, multi-criteria decision making (MCDM) has been widely employed in planning ESS. This paper aims to provide a critical review of MCDM for the deployment solutions of RES and ESS in carbon neutral building applications. A conceptual illustration is also presented to synthesize the literature review and explain the key methodologies of MCDM.© 2023 The Author(s). Open Access This chapter is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/), which permits any noncommercial use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license and indicate if changes were made.fi=vertaisarvioitu|en=peerReviewed

    A carbonation and chloride induced corrosion model for hot-dip galvanised reinforcement bar material in concrete

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    This paper focuses on methodological issues relevant to corrosion risk prediction models. A model was developed for the prediction of corrosion rates associated with hot-dip galvanised reinforcement bar material in concrete exposed to carbonation and chlorides in outdoor environment. One-year follow-up experiments, over five years, were conducted at various carbonation depths and chloride contents. The observed dependence of corrosion rate on the depth of carbonation and chloride content is complex indicating that the interaction between the carbonation and chloride influencing the corrosion. A non-linear corrosion model was proposed with statistical analysis to model the relationship between the corrosion rate and the test parameters. The main methodological contributions are (i) the proposed modeling approach able to take into account the uncertain measurement errors including unobserved systematic and random heterogeneity over different measured specimens and correlation for the same specimen across different measuring times, which best suits the measurement data; (ii) the developed model in which an interaction parameter is introduced especially to account for the contribution and the degree of the unobserved carbonation-chloride interaction. The proposed model offers greater flexibility for the modelling of measurement data than traditional models

    Hydrate dissociation induced by gas diffusion from pore water to drilling fluid in a cold wellbore

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    It is a common view that the high temperature of the drilling fluid can lead to the dissociation of gas hydrate during drilling through hydrate-bearing sediments. This study indicates that the hydrate dissociation in wellbore can also be induced by gas diffusion from pore water to drilling fluid even if the temperature (and the pressure if necessary) of the drilling fluid is well controlled to keep the conditions of hydrate-bearing sediments along the hydrate equilibrium boundary. The dissociation of gas hydrate was modelled based on Fick's first law. It was found that the dissociation rate mainly depended on the temperature of the sediments. The locations of dissociation front of CH4 hydrate and CO2 hydrate in wellbore were calculated as a function of time. The impacts of the hydrate dissociation on the wellbore stability and the resistivity well logging in sediments were evaluated.Cited as: Sun, Y., Lu, H., Lu, C., Li, S., Lv, X. Hydrate dissociation induced by gas diffusion from pore water to drilling fluid in a cold wellbore. Advances in Geo-Energy Research, 2018, 2(4): 410-417, doi: 10.26804/ager.2018.04.0

    Influence of lunar semidiurnal tides on groundwater dynamics in estuarine aquifers

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    The influence of lunar semidiurnal tides on coastal groundwater aquifers has been conceptualized for decades. However, a thorough understanding of the impact of tides on groundwater dynamics due to the widely distributed waterways and heterogeneous sediments in estuarine aquifers, is still needed. This study shows the tidal impact on groundwater dynamics in the Pearl River estuary in southeast China through wavelet and time series analysis. The groundwater level and electrical conductivity (EC), as well as tidal levels, were monitored in several observation wells and tidal stations to determine how the estuarine groundwater levels respond to tidal forcing. The results show that the groundwater fluctuations have short periodicities of 0.51 and 1 day corresponding to major tidal constituents of M2 (semidiurnal) and K1 and O1 (diurnal) signals, respectively. The significant impacts decrease with increasing distance inland of the locations of the wells. Additionally, the coherence analysis displays a higher correlation between tides and groundwater levels for the spring tide than for the neap tide. The tidal influences on groundwater EC are weak compared to those on groundwater levels. In addition, when the tidal level increases, the EC decreases in wells located in the estuarine entrance. This is related to the high salinity of retained paleo-seawater in the strata lenses. A conceptual model is proposed to illustrate the complex groundwater flow dynamics. The model may provide useful insights into the understanding of similar systems located in geographically different coastal regions.© 2020 Springer. This is a post-peer-review, pre-copyedit version of an article published in Hydrogeology Journal. The final authenticated version is available online at: http://dx.doi.org/10.1007/s10040-020-02136-8fi=vertaisarvioitu|en=peerReviewed

    Exploring the safety, effectiveness, and cost-effectiveness of a Chinese patent medicine (Fufang E’jiao syrup) for alleviating cancer-related fatigue : a protocol for a randomized, double-blinded, placebo-controlled, multicenter trial

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    Objective: To provide higher level evidence on the benefits of a Chinese patent medicine (CPM) (Fufang E’jiao Syrup, FFEJS) for alleviating cancer-related fatigue (CRF), this article describes a protocol for a randomized controlled trial. Methods/design: We designed a double-blind, placebo-controlled stratified permuted block randomization clinical trial on CRF among 3 types of cancer in China. Participants will be equally allocated to FFEJS group or placebo group according to the randomization sequence and the hospitals they were enrolled at. Each patient will receive 20 ml of either the study formula FFEJS or a placebo formula, 3 times a day for 6 weeks. The follow-up period will be another 4 weeks for safety evaluation. The primary outcome is the difference in improvement of fatigue as measured with the Revised Piper Fatigue Scale-Chinese Version (RPFS-CV). Secondary outcomes include change in fatigue (measured by routine blood panel and hormones in peripheral blood) and QoL (measured by Edmonton symptom assessment scale and Functional Assessment of Cancer Therapy). Patient safety will be measured by liver, renal or cardiac damage, and the risk of FFEJS having a tumor promotion and progression effect will be monitored throughout this study. Cost-effectiveness will also be evaluated mainly by incremental cost per each quality-adjusted life year gained. Discussion: This article describes the study design of a CPM for CRF in patients with advanced cancer through exploring the effectiveness, safety, and cost-effectiveness of FFEJS. Trial registration: ClinicalTrials.gov, NCT04147312. Registered on 1 Sep 2019

    Improving the energy efficiency of buildings based on fluid dynamics models: a critical review

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    The built environment is the global sector with the greatest energy use and greenhouse gas emissions. As a result, building energy savings can make a major contribution to tackling the current energy and climate change crises. Fluid dynamics models have long supported the understanding and optimization of building energy systems and have been responsible for many important technological breakthroughs. As Covid-19 is continuing to spread around the world, fluid dynamics models are proving to be more essential than ever for exploring airborne transmission of the coronavirus indoors in order to develop energy-efficient and healthy ventilation actions against Covid-19 risks. The purpose of this paper is to review the most important and influential fluid dynamics models that have contributed to improving building energy efficiency. A detailed, yet understandable description of each model’s background, physical setup, and equations is provided. The main ingredients, theoretical interpretations, assumptions, application ranges, and robustness of the models are discussed. Models are reviewed with comprehensive, although not exhaustive, publications in the literature. The review concludes by outlining open questions and future perspectives of simulation models in building energy research

    A decade of complex fractionated electrograms catheter-based ablation for atrial fibrillation: Literature analysis, meta-analysis and systematic review

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    AbstractBackgroundIt has been a decade since the complex fractionated atrial electrograms (CFAEs) were first established following the publication of Nademanee's standards. However, the status and focus of CFAE research are unclear, as is the efficacy of additional CFAE ablation in atrial fibrillation (AF). This literature review and meta-analysis were designed to determine the status of CFAE research and the efficacy and complications of CFAE ablation alone, pulmonary vein isolation (PVI) alone and PVI plus CFAE ablation in AF.MethodsWith the assistance from reference librarians and investigators trained in systematic review, we conducted a literature search of MEDLINE (via PubMed), Embase, the Cochrane Library, ScienceDirect, Wiley Blackwell and Web of Knowledge, using “complex fractionated atrial electrograms” for MeSH and keyword search.ResultsThe literature on CFAEs increased from 2007, mainly focusing on mapping studies, with mechanism studies increasing significantly from 2012. Fifteen trials with 1525 patients were qualified for our meta-analysis. Success rates were as follows. Overall (P < 0.001): CFAE ablation alone, 23.5–26.2%; PVI, 64.7%; PVI plus CFAE ablation, 67.0%. Single ablation: PVI, 60.4%; PVI plus CFAEs, 68.8% (OR 1.53, 95% CI 1.07–2.20, P = 0.02). Re-ablation: PVI, 69.0%; PVI plus CFAEs, 77.2% (OR 1.54, 95% CI 1.06–2.24, P = 0.02). Paroxysmal AF: PVI, 76.7%; PVI plus CFAEs, 79.1% (OR 1.20, 95% CI 0.79–1.81, P = 0.39). Persistent or permanent AF: PVI, 47.9%; PVI plus CFAEs, 58.7% (OR = 1.59, 95% CI 1.13–2.24, P = 0.008). Complication rates: PVI, 2.6%; PVI plus CFAEs, 3.4% (OR 1.22, 95% CI 0.58–2.57, P = 0.61).ConclusionsIn the literature, CFAE mapping studies preceded mechanism studies. CFAE ablation alone is insufficient for the treatment of AF. Additional CFAE ablation after adequate PVI or PVI plus linear ablation improves the outcome of single ablation and re-ablation without increasing complications, especially in persistent or permanent AF. There are insufficient data to support a similar improvement in paroxysmal AF or inducible AF after PVI for paroxysmal AF
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