59 research outputs found
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“Performance Comparison of a Heating Tower Heat Pump and an Air-Source Heat Pump: A Comprehensive Modeling and Simulation Study
The heating tower heat pump (HTHP) is proposed as an alternative to the conventional air-source heat pump (ASHP). To investigate the performance improvements of the HTHP over the ASHP, a comprehensive comparison between the two systems was carried out based on a simulation study. Physics-based models for the ASHP and HTHP were developed. The performance of the ASHP under frosting conditions was corrected with a newly developed frosting map, and the regeneration penalization was considered for the HTHP. Based on the models and corrections, hourly simulations were carried out in an office building in Nanjing, China. The results show that the average energy efficiency of the HTHP in summer is 23.1% higher than that of the ASHP due to the water-cooled approach adopted by the HTHP. In winter, the HTHP achieves an increase of 7.4% in efficiency due to the frost free and energy storage characteristics. While the initial cost of the HTHP is 1.2% higher than that of the ASHP, the HTHP can still save 9.7% cost in a 10-year period because of its lower power consumption.</p
Research on Comprehensive Evaluation of Electricity Market Risk Based on Subjective and Objective Weighting
[Introduction] With the emphasis and promotion of the electricity market system construction by the government, the electricity market is constantly growing towards a deeper and more unified direction. In order to promote the electricity market construction, the influence factors of the electricity market risk and its evaluation remain to be studied further. [Method] Based on the consideration of the whole cycle of electricity market trading, this paper took pre-trade risk, during-trade risk, and post-trade riskas the entry points, integrated the existing risks in each stage of electricity market, and established the risk evaluation index system for electricity market. Based on the thought of subjective and objective weighting, analytic hierarchy process (AHP) and entropy weight method were used to assign weights to the index system respectively, and fuzzy comprehensive evaluation (FCE) was adopted to evaluate the comprehensive risk level of the electricity market. [Result] The rationality, comprehensiveness and validity of the proposed model are verified through the analysis of the calculation examples of different electricity markets. [Conclusion] The model eatablished in this paper can conduct a comprehensive risk evaluation for the electricity market, and provide a theoretical reference for the construction of the risk system of the electricity market and its future development direction
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Model-based optimal operation of heating tower heat pump systems
In current applications of heating tower heat pumps (HTHPs), the systems tend to run with constant speed or fixed set points, which can be inefficient under varying weather data and building loads. To address this issue, this study proposes a model-based optimal operation of the HTHPs to achieve energy savings in both cooling and heating modes. Firstly, a physics-based model for an existing HTHP system was developed. Then, artificial neural network (ANN) models were developed and trained with vast amount of operational data generated by the physics-based model. The ANN models were found to be highly accurate (average relative error less than 1%) and computationally efficient (about 300 times faster than the physics-based model). After that, three optimal approaches were proposed to minimize the total energy consumption of the HTHP system. Approach 1 optimizes the load distribution between different heat pump units. Approach 2 optimizes the speed of fans and pumps by fixed approach and range of the condenser water (or evaporator solution). Approach 3 optimizes both the load distribution and the speed of fans and pumps. The optimization is implemented by using the ANN models, proposed approaches, and a genetic algorithm via a case study. The results show that the energy savings in the cooling season are 2.7%, 11.4%, and 14.8% by the three approaches, respectively. In the heating season, the energy savings of the three approaches are 1.6%, −1.4%, and 4.7%, respectively. Moreover, the thermodynamic performance in typical days was analyzed to investigate how energy savings could be achieved.
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Diagnostic Significance of Serum IgG Galactosylation in CA19-9-Negative Pancreatic Carcinoma Patients
Background: Although Carbohydrate antigen 19-9 (CA19-9) is considered clinically useful and informative for pancreatic carcinoma (PC), false positive results, and false negative results have restricted its clinical use. Especially missed or delayed diagnosis of PC patients with negative CA19-9 value limited the utility. To improve prognosis of PC patients, the discovery of reliable biomarkers to assist CA19-9 is desired. Serum IgG galactosylation based on our previous report was altered in PC patients comparing to healthy controls. The objective of this study was to explore the diagnostic significance of IgG galactosylation in assisting CA19-9 for PC in a comprehensive way.Methods: Serum IgG galactosylation profiles were analyzed by MALDI-MS in cohort 1 (n = 252) and cohort 2 in which all CA19-9 levels were negative (n = 133). In each cohort, not only healthy controls and PC patients but also benign pancreatic disease (BPD) patients were enrolled. Peaks were acquired by the software of MALDI-MS sample acquisition, followed by being processed and analyzed by the software of Progenesis MALDI. IgG Gal-ratio, which was calculated from the relative intensity of peaks G0, G1, and G2 according to the formula (G0/(G1+G2×2)), was employed as an index for indicating the distribution of IgG galactosylation.Results: The Gal-ratio was elevated in PC comparing with that in non-cancer group (healthy controls and BPD). The area under the receiver operating characteristic curve (AUC) of IgG Gal-ratio was higher than that of CA19-9 (0.912 vs. 0.814). The performance was further improved when Gal-ratio and CA19-9 were combined (AUC: 0.928). Meanwhile, Gal-ratio also had great diagnostic value with a sensitivity of 92.31% (AUC: 0.883) in detection of PC at early stage. Notably, IgG Gal-ratio has great sensitivity (90.63%) and specificity (76.81%) in CA19-9-negative PC patients.Conclusions: IgG Gal-ratio had a great performance in detection of PC and could be used to assist CA19-9 in improving diagnosis performance through early stage detection, differentiation from BPD, and PC diagnosis with CA19-9-negative level
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Safety and Tolerability of SRX246, a Vasopressin 1a Antagonist, in Irritable Huntington\u27s Disease Patients-A Randomized Phase 2 Clinical Trial.
SRX246 is a vasopressin (AVP) 1a receptor antagonist that crosses the blood-brain barrier. It reduced impulsive aggression, fear, depression and anxiety in animal models, blocked the actions of intranasal AVP on aggression/fear circuits in an experimental medicine fMRI study and demonstrated excellent safety in Phase 1 multiple-ascending dose clinical trials. The present study was a 3-arm, multicenter, randomized, placebo-controlled, double-blind, 12-week, dose escalation study of SRX246 in early symptomatic Huntington\u27s disease (HD) patients with irritability. Our goal was to determine whether SRX246 was safe and well tolerated in these HD patients given its potential use for the treatment of problematic neuropsychiatric symptoms. Participants were randomized to receive placebo or to escalate to 120 mg twice daily or 160 mg twice daily doses of SRX246. Assessments included standard safety tests, the Unified Huntington\u27s Disease Rating Scale (UHDRS), and exploratory measures of problem behaviors. The groups had comparable demographics, features of HD and baseline irritability. Eighty-two out of 106 subjects randomized completed the trial on their assigned dose of drug. One-sided exact-method confidence interval tests were used to reject the null hypothesis of inferior tolerability or safety for each dose group vs. placebo. Apathy and suicidality were not affected by SRX246. Most adverse events in the active arms were considered unlikely to be related to SRX246. The compound was safe and well tolerated in HD patients and can be moved forward as a candidate to treat irritability and aggression
Further insight into genetic variation and haplotype diversity of <em>Cherry virus A</em> from China.
Cherry virus A (CVA) infection appears to be prevalent in cherry plantations worldwide. In this study, the diversity of CVA isolates from 31 cherry samples collected from different orchards around Bohai Bay in northeastern China was analyzed. The complete genome of one of these isolates, ChYT52, was found to be 7,434 nt in length excluding the poly (A) tail. It shares between 79.9-98.7% identity with CVA genome sequences in GenBank, while its RdRp core is more divergent (79.1-90.7% nt identity), likely as a consequence of a recombination event. Phylogenetic analysis of ChYT52 genome with CVA genomes in Genbank resulted in at least 7 major clusters plus additional 5 isolates alone at the end of long branches suggesting the existence of further phylogroups diversity in CVA. The genetic diversity of Chinese CVA isolates from 31 samples and GenBank sequences were analyzed in three genomic regions that correspond to the coat protein, the RNA-dependent RNA polymerase core region, and the movement protein genes. With few exceptions likely representing further recombination impact, the trees various trees are largely congruent, indicating that each region provides valuable phylogenetic information. In all cases, the majority of the Chinese CVA isolates clustering in phylogroup I, together with the X82547 reference sequence from Germany. Statistically significant negative values were obtained for Tajima's D in the three genes for phylogroup I, suggesting that it may be undergoing a period of expansion. There was considerable haplotype diversity in the individual samples and more than half samples contained genetically diverse haplotypes belonging to different phylogroups. In addition, a number of statistically significant recombination events were detected in CVA genomes or in the partial genomic sequences indicating an important contribution of recombination to CVA evolution. This work provides a foundation for elucidation of the epidemiological characteristics and evolutionary history of CVA populations
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