993 research outputs found

    Advanced CO2 Capture Process Using MEA Scrubbing: Configuration of a Split Flow and Phase Separation Heat Exchanger

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    AbstractCO2 capture process using aqueous Monoethanolamine (MEA) scrubbing is a well-proven and commercially-ready technology for reducing CO2 emission to the atmosphere. Although the MEA scrubbing is the one of the most suitable technologies for post-combustion CO2 capture, the MEA process has a critical problem which is high consumption of reboiler heat energy for solvent regeneration. In order to reduce the reboiler heat requirement, this paper suggests an advanced configuration of MEA process which consists of split flow and a phase separation heat exchanger. The split flow permits to reduce the reflux ratio in the stripper and the phase separation heat exchanger permits to alleviate preheating duty loss. As a result, the regeneration energy of the advanced process is reduced by 2.84GJ/ton CO2, which is lower than one of the reference process by 27%.CO2 capture; post combustion CO2 capture; advanced stripper configuration; cold solvent split; rich vapor compressio

    Successful Features of Crowdfunding Campaigns: An Analysis of Requests for Coronavirus Food Relief

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    Crowdfunding is an emerging industry in the past decades, which proliferates and has attracted an enormous population from the public to be involved in various funding projects in multiple fields such as business entrepreneurship, healthcare, and fintech. Meanwhile, charitable crowdfunding platforms such as GoFundMe, Indiegogo, and Kickstarter have allowed internet users to provide help and donation to the fundraisers directly. As the year 2020 is surrounded by the COVID-19 global pandemic spreading out the world, the topic of coronavirus relief has surged. Thus, it is worthy of evaluating the crowdfunding campaign\u27s effectiveness during the coronavirus context by making a connection between fundraising activities and coronavirus relief. This paper aims to investigate the effects of various factors affecting a donation-based crowdfunding campaign for coronavirus relief of food donation in the United States and determine the significant factors affecting the campaign\u27s success rate. To achieve this research purpose, secondary data were extensively collected from the crowdfunding platform GoFundMe for regression analysis. The sample data was derived from crowdfunding campaigns launched from March 1st, 2020, to May 31st, 2020. During this period, the United States was severely affected by the COVID-19 pandemic with an exponentially surged number of confirmed cases. This paper derives the independent variables that have been examined from previous studies and further applies in the coronavirus context to identify whether these factors are significant influencers to the success of crowdfunding campaigns for coronavirus relief of food donation. The factors being examined include target funding amount, the existence of spelling mistakes, the presence of pictures, video, social network sites, project updates, comments between fundraisers and backers, and links to external websites. That the significant factors contributing to a successful funding project are similar, as identified in previous reward-based and equity crowdfunding studies. On the other hand, several independent variables\u27 effectiveness varied between the normal scenario and the coronavirus context, as such variables demonstrate a much compelling role to attract donors for the coronavirus relief activations. The analysis is valuable and worthy of different viewpoints. First, understanding the donor\u27s motivation and the success features of funding projects is valuable for fundraisers to have a strategic mindset for decision-making criteria when initiating funding projects to attract more donors and the amount of money. Second, because of the lack of literature focusing on examining the success features for donation-based crowdfunding campaigns, this study fills the gap and further focus on the crowdfunding activations in the context of coronavirus food relief in the US. Therefore, this study provides significant insight to understand the dynamics of the donation-based crowdfunding campaign and provides a recommendation to develop coronavirus relief more efficiently

    Behavioural Study of Concrete Surface Crack Filling Conditions on Surface Rayleigh Wave

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    In the recent studies of concrete surface crack non-destructive test (NDT), the environmental factors are seldom to be taken into assessment consideration using Rayleigh wave (R-wave) propagation method. Dust, fine sand or water that accumulated in the concrete surface cracks might potentially affect the behaviour of R-wave when it propagated through the cracks. In this study, the effects of filling conditions in concrete surface crack to the properties of R-wave were examined. The targeted parameters that used for studying the behaviour of R-wave are the arrival time of R-wave and its corresponding amplitude. Numerical simulations were conducted for determining the changes of R-wave amplitudes and arrival time when it propagated through a concrete model with a surface crack which containing various filling conditions. Sand and charcoal powder were the materials used for filling the concrete cracks. The results of numerical simulations were then justified by experimental measurements. The comparison between the results of numerical simulation and experimental measurement generated a conclusion where R-wave arrival time and its corresponding amplitude is independent from the predefined filling conditions of concrete surface crack

    Facile synthesis of metal-free organic dyes featuring a thienylethynyl spacer for dye sensitized solar cells

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    In this article, we report the facile synthesis of metal-free dyes 6 and 7, their solution-based optical and redox properties and their use as sensitizers in dye-sensitized solar cells (DSSCs). Our studies indicate that the addition of the second thiophene unit in dye 7, decreases the oxidation and reduction potential and consequently the band gap of the molecule compared to 6. Furthermore, increasing the length of the conjugated spacer also affects on the properties of the DSSCs, with dye 7 providing a higher power conversion efficiency compared to 6 (η = 4.49 versus 3.23%)

    Evaluation of the brain activation induced by functional electrical stimulation and voluntary contraction using functional magnetic resonance imaging

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    BACKGROUND: To observe brain activation induced by functional electrical stimulation, voluntary contraction, and the combination of both using functional magnetic resonance imaging (fMRI). METHODS: Nineteen healthy young men were enrolled in the study. We employed a typical block design that consisted of three sessions: voluntary contraction only, functional electrical stimulation (FES)-induced wrist extension, and finally simultaneous voluntary and FES-induced movement. MRI acquisition was performed on a 3.0 T MR system. To investigate activation in each session, one-sample t-tests were performed after correcting for false discovery rate (FDR; p < 0.05). To compare FES-induced movement and combined contraction, a two-sample t-test was performed using a contrast map (p < 0.01). RESULTS: In the voluntary contraction alone condition, brain activation was observed in the contralateral primary motor cortex (MI), thalamus, bilateral supplementary motor area (SMA), primary sensory cortex (SI), secondary somatosensory motor cortex (SII), caudate, and cerebellum (mainly ipsilateral). During FES-induced wrist movement, brain activation was observed in the contralateral MI, SI, SMA, thalamus, ipsilateral SII, and cerebellum. During FES-induced movement combined with voluntary contraction, brain activation was found in the contralateral MI, anterior cingulate cortex (ACC), SMA, ipsilateral cerebellum, bilateral SII, and SI. The activated brain regions (number of voxels) of the MI, SI, cerebellum, and SMA were largest during voluntary contraction alone and smallest during FES alone. SII-activated brain regions were largest during voluntary contraction combined with FES and smallest during FES contraction alone. The brain activation extent (maximum t score) of the MI, SI, and SII was largest during voluntary contraction alone and smallest during FES alone. The brain activation extent of the cerebellum and SMA during voluntary contraction alone was similar during FES combined with voluntary contraction; however, cerebellum and SMA activation during FES movement alone was smaller than that of voluntary contraction alone or voluntary contraction combined with FES. Between FES movement alone and combined contraction, activated regions and extent due to combined contraction was significantly higher than that of FES movement alone in the ipsilateral cerebellum and the contralateral MI and SI. CONCLUSIONS: Voluntary contraction combined with FES may be more effective for brain activation than FES-only movements for rehabilitation therapy. In addition, voluntary effort is the most important factor in the therapeutic process

    High performance dye sensitized solar cells by adding titanate co-adsorbant

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    The open circuit voltage and the short circuit current density of dye sensitized solar cells were increased by adding a titanate co-adsorbant as a blocking agent. This blocking agent effectively prevents back electron transfer. As a result, DSSCs with titanate co-adsorbant showed significantly increased energy conversion efficiency.close0

    Tunable Magnetic Properties in Sr2_2FeReO6_6 Double-Perovskite

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    Double-perovskite oxides have attracted recent attention due to their attractive functionalities and application potential. In this paper, we demonstrate the effect of dual controls, i.e., the deposition pressure of oxygen (PO2_O2) and lattice mismatch (ϵ\epsilon), on tuning magnetic properties in epitaxial double-perovskite Sr2_2FeReO6_6 films. In a nearly-lattice-matched Sr2_2FeReO6_6/SrTiO3_3 film, the ferrimagnetic-to-paramagnetic phase transition occurs when PO2_O2 is reduced to 30 mTorr, probably due to the formation of Re4+^{4+} ions that replace the stoichiometric Re5+^{5+} to cause disorders of BB-site ions. On the other hand, a large compressive strain or tensile strain shifts this critical PO2_O2 to below 1 mTorr or above 40 mTorr, respectively. The observations could be attributed to the modulation of BB-site ordering by epitaxial strain through affecting elemental valence. Our results provide a feasible way to expand the functional tunability of magnetic double-perovskite oxides that hold great promise for spintronic devices.Comment: Main text 18 pages, 5 figures; Supplementary information 8 pages, 4 figure

    Expressions of HSP70 and HSP27 in Hepatocellular Carcinoma

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    The heat shock proteins (HSPs) are ubiquitous molecules induced in cells exposed to various stress conditions, including carcinogenesis. The HSP70 and HSP27 among HSPs are of special relevance in human cancer inhibiting apoptosis. The aim of this study is to investigate the expressions of HSP70 and HSP27 in hepatocellular carcinoma (HCC) in association to tumor cell proliferation and apoptosis. We examined the expressions of HSP70 and HSP27 by immunohistochemical staining in 71 cases of HCC, and then related their expressions to clinicopathologic parameters and expressions of p53, Ki-67 and Apotag. HSP70 and HSP27 were frequently stained in the cytoplasm and nuclei of tumor cells, but not in the non-neoplastic hepatocytes. Immunoreactivities of HSP70 and HSP27 were observed in 56.3% and 61.9% of HCCs, respectively. HSP70 immunoreactivity correlated with high Ki-67 labeling indices (LIs) (p=0.0159), large tumor size (p=0.0129), presence of portal vein invasion (p=0.0231), and high tumor stage (p=0.0392). HSP27 immunoreactivity significantly related with the subgroup of HBV-associated HCCs (p=0.0003), but not with the others. Both HSP70 and HSP27 immunoreactivities showed no relation to Apotag LIs or p53 immunoreactivity. In conclusion, expressions of HSP70 and HSP27 may play an important role in hepatocarcinogenesis, and especially HSP70 showed a close relationship to the pathological parameters associated with tumor progression and high Ki-67 LIs. Our results could be additional evidence that HSP70 expressions can contribute to not only hepatocarcinogenesis but also tumor progression by promoting tumor cell proliferation

    Business intelligence in banking: A literature analysis from 2002 to 2013 using Text Mining and latent Dirichlet allocation

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    telligence applications for the banking industry. Searches were performed in relevant journals resulting in 219 articles published between 2002 and 2013. To analyze such a large number of manuscripts, text mining techniques were used in pursuit for relevant terms on both business intelligence and banking domains. Moreover, the latent Dirichlet allocation modeling was used in or- der to group articles in several relevant topics. The analysis was conducted using a dictionary of terms belonging to both banking and business intelli- gence domains. Such procedure allowed for the identification of relationships between terms and topics grouping articles, enabling to emerge hypotheses regarding research directions. To confirm such hypotheses, relevant articles were collected and scrutinized, allowing to validate the text mining proce- dure. The results show that credit in banking is clearly the main application trend, particularly predicting risk and thus supporting credit approval or de- nial. There is also a relevant interest in bankruptcy and fraud prediction. Customer retention seems to be associated, although weakly, with targeting, justifying bank offers to reduce churn. In addition, a large number of ar- ticles focused more on business intelligence techniques and its applications, using the banking industry just for evaluation, thus, not clearly acclaiming for benefits in the banking business. By identifying these current research topics, this study also highlights opportunities for future research
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