491 research outputs found

    Negative Emission Power Plants:Thermodynamic Modeling and Evaluation of a Biomass-Based Integrated Gasification Solid Oxide Fuel Cell/Gas Turbine System for Power, Heat, and Biochar Co-Production—Part 1

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    This article is the first of a two-part series presenting the thermodynamic evaluation and techno-economics of developing negative-emission power plants. The aim of this research is to evaluate the potential of biochar co-production in negative-emission power plants based on biomass-fed integrated gasification solid oxide fuel cell systems with carbon capture and storage (BIGFC/CCS) units. The influence of two gasification agents, namely, air and steam-oxygen, on the proposed system is investigated. In Part I, we present the thermodynamic models. A sensitivity analysis is carried out to investigate the system response to stepwise increase in biochar co-production (up to 10% by weight). Providing a secondary oxy-combustor in the steam-oxygen gasification case has been shown to be a solution to meet the heat requirements of the allothermal gasification process. A comprehensive exergy analysis indicated significant efficiency improvement for the steam-oxygen gasification case. The results show that the biomass steam-oxygen gasification yields the higher electrical exergy efficiency (48.3%) and combined heat and power (CHP) exergy efficiency (54.6%) for the similar rates of biochar co-production. The specific power output per unit of CO2 stored is 2.65 MW/(kg/s) and 3.58 MW/(kg/s) for the air and steam-oxygen gasification cases, respectively, when the biochar is co-produced at 10% by weight for the given biomass flow of 20 kg/s. Moreover, the total CO2 stored due to the proposed system is calculated as 133.9 t/h, and it is estimated to remove 1.17 Mt of CO2 from the atmosphere annually (when the biochar-based carbon storage is also considered). The models are used for the techno-economic analysis presented in Part II of the series

    Retraction and Generalized Extension of Computing with Words

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    Fuzzy automata, whose input alphabet is a set of numbers or symbols, are a formal model of computing with values. Motivated by Zadeh's paradigm of computing with words rather than numbers, Ying proposed a kind of fuzzy automata, whose input alphabet consists of all fuzzy subsets of a set of symbols, as a formal model of computing with all words. In this paper, we introduce a somewhat general formal model of computing with (some special) words. The new features of the model are that the input alphabet only comprises some (not necessarily all) fuzzy subsets of a set of symbols and the fuzzy transition function can be specified arbitrarily. By employing the methodology of fuzzy control, we establish a retraction principle from computing with words to computing with values for handling crisp inputs and a generalized extension principle from computing with words to computing with all words for handling fuzzy inputs. These principles show that computing with values and computing with all words can be respectively implemented by computing with words. Some algebraic properties of retractions and generalized extensions are addressed as well.Comment: 13 double column pages; 3 figures; to be published in the IEEE Transactions on Fuzzy System

    Dementia Assessment Using Mandarin Speech with an Attention-based Speech Recognition Encoder

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    Dementia diagnosis requires a series of different testing methods, which is complex and time-consuming. Early detection of dementia is crucial as it can prevent further deterioration of the condition. This paper utilizes a speech recognition model to construct a dementia assessment system tailored for Mandarin speakers during the picture description task. By training an attention-based speech recognition model on voice data closely resembling real-world scenarios, we have significantly enhanced the model's recognition capabilities. Subsequently, we extracted the encoder from the speech recognition model and added a linear layer for dementia assessment. We collected Mandarin speech data from 99 subjects and acquired their clinical assessments from a local hospital. We achieved an accuracy of 92.04% in Alzheimer's disease detection and a mean absolute error of 9% in clinical dementia rating score prediction.Comment: submitted to IEEE ICASSP 202

    Feasibility of Bispectral Index-Guided Propofol Infusion for Flexible Bronchoscopy Sedation: A Randomized Controlled Trial

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    There are safety issues associated with propofol use for flexible bronchoscopy (FB). The bispectral index (BIS) correlates well with the level of consciousness. The aim of this study was to show that BIS-guided propofol infusion is safe and may provide better sedation, benefiting the patients and bronchoscopists.After administering alfentanil bolus, 500 patients were randomized to either propofol infusion titrated to a BIS level of 65-75 (study group) or incremental midazolam bolus based on clinical judgment to achieve moderate sedation. The primary endpoint was safety, while the secondary endpoints were recovery time, patient tolerance, and cooperation.The proportion of patients with hypoxemia or hypotensive events were not different in the 2 groups (study vs. control groups: 39.9% vs. 35.7%, p = 0.340; 7.4% vs. 4.4%, p = 0.159, respectively). The mean lowest blood pressure was lower in the study group. Logistic regression revealed male gender, higher American Society of Anesthesiologists physical status, and electrocautery were associated with hypoxemia, whereas lower propofol dose for induction was associated with hypotension in the study group. The study group had better global tolerance (p<0.001), less procedural interference by movement or cough (13.6% vs. 36.1%, p<0.001; 30.0% vs. 44.2%, p = 0.001, respectively), and shorter time to orientation and ambulation (11.7±10.2 min vs. 29.7±26.8 min, p<0.001; 30.0±18.2 min vs. 55.7±40.6 min, p<0.001, respectively) compared to the control group.BIS-guided propofol infusion combined with alfentanil for FB sedation provides excellent patient tolerance, with fast recovery and less procedure interference.ClinicalTrials. gov NCT00789815

    The Antiinfective Effects of Velvet Antler of Formosan Sambar Deer (Cervus unicolor swinhoei) on Staphylococcus aureus-Infected Mice

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    We assayed the effects of velvet antler (VA) of Formosan sambar deer (Cervus unicolor swinhoei) and its extracts on the anti-infective activity against pathogenic Staphylococcus aureus in vitro and in vivo in this study. In vitro data indicated that the VA extracts stimulated the proliferation of resting splenocytes and macrophages in a dose-dependent manner up to the highest concentration used (150 μg mL−1). The production of proinflammatory cytokines (TNF-α, IL-6, IL-12) by lipoteichoic acid was significantly suppressed after being cocultured with the VA extracts in a dose-dependent manner. Animal test in S. aureus-infected mice demonstrated that the numbers of bacteria determined in the kidneys and peritoneal lavage fluid of S. aureus-infected mice were significantly higher than those found in the same organs of mice pretreated with the VA samples. Moreover, the highly enhanced phagocytic activity of macrophages was further verified after in vitro treatment with the VA samples. The protective mechanisms of the VA samples might include an immune enhancer and an inflammatory cytokine suppressor

    Correlation of virulence genes to clinical manifestations and outcome in patients with Streptococcus dysgalactiae subspecies equisimilis bacteremia

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    Background/PurposeStreptococcus dysgalactiae subsp. equisimilis (SDSE) is increasingly recognized as a human pathogen responsible for invasive infection and streptococcal toxic shock syndrome (STSS). The pathogen possesses virulence genes that resemble those found in Streptococcus pyogenes (GAS). We analyzed the association between these specific toxic genes, clinical presentations, and outcome in patients with SDSE infections.MethodsPatients (older than 18 years) with community-acquired invasive bacteremia caused by SDSE bacteremia who were undergoing treatment at China Medical University Hospital from June 2007 to December 2010 were included in this study. Multiplex polymerase chain reaction was performed to identify virulence genes of the SDSE isolates. Demographic data, clinical presentations, and outcome in patients with SDSE infections were reviewed and analyzed.ResultsForty patients with 41 episodes of SDSE bacteremia were reviewed. The median age of the patients with SDSE infection was 69.7 years; 55% were female and 78% had underlying diseases. Malignancy (13, 33%) and diabetes mellitus (13, 33%) were the most common comorbidities. The 30-day mortality rate was 12%. Compared with the survivors, the non-survivors had a higher rate of diabetes mellitus (80% vs. 26%), liver cirrhosis (60% vs.11%), shock (60% vs.17%), STSS (60% vs. 8%), and a high Pittsburgh bacteremia score >4 (40% vs. 6%). Most isolates had scpA, ska, saga, and slo genes, whereas speC, speG, speH, speI, speK, smez, and ssa genes were not detected. speA gene was identified only in one patient with STSS (1/6, 17%). All isolates were susceptible to penicillin, cefotaxime, levofloxacin, moxifloxacin, vancomycin, and linezolid.ConclusionIn invasive SDSE infections, most isolates carry putative virulence genes, such as scpA, ska, saga, and slo. Clinical SDSE isolates in Taiwan remain susceptible to penicillin cefotaxime, and levofloxacin

    A Macroporous TiO2 Oxygen Sensor Fabricated Using Anodic Aluminium Oxide as an Etching Mask

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    An innovative fabrication method to produce a macroporous Si surface by employing an anodic aluminium oxide (AAO) nanopore array layer as an etching template is presented. Combining AAO with a reactive ion etching (RIE) processes, a homogeneous and macroporous silicon surface can be effectively configured by modulating AAO process parameters and alumina film thickness, thus hopefully replacing conventional photolithography and electrochemical etch methods. The hybrid process integration is considered fully CMOS compatible thanks to the low-temperature AAO and CMOS processes. The gas-sensing characteristics of 50 nm TiO2 nanofilms deposited on the macroporous surface are compared with those of conventional plain (or non-porous) nanofilms to verify reduced response noise and improved sensitivity as a result of their macroporosity. Our experimental results reveal that macroporous geometry of the TiO2 chemoresistive gas sensor demonstrates 2-fold higher (∼33%) improved sensitivity than a non-porous sensor at different levels of oxygen exposure. In addition, the macroporous device exhibits excellent discrimination capability and significantly lessened response noise at 500 °C. Experimental results indicate that the hybrid process of such miniature and macroporous devices are compatible as well as applicable to integrated next generation bio-chemical sensors
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