Mathematical and experimental evaluation of a mini-channel PV/T and thermal panel in summer mode

In this paper, a mini-channel PV/T and mini-channel thermal panel hot water system is presented. The thermal panels in this system use mini-channel tube as the heat exchanger, which has a small hydraulic diameter and large heat exchanger area, and this special structure can improve the heat transfer coefficient at the same flow rate than the conventional type. The performance of this system for generating hot water and electricity in summer has been tested, and a simulation model of this operating mode has been developed. Based on a typical day's weather data, the simulation model is verified, and the experimental and simulated results agree with each other very well. The results reveal that the experimental and simulated electrical efficiencies of PV/T panels are 11.5% and 12.6%, respectively. The experimental and simulated thermal efficiencies of thermal collectors are 46.8% and 48.0%, respectively. The experimental and simulated final water temperatures in the tank are 59.3 °C and 60.9 °C, respectively. Based on these results, an error analysis is carried out. The experimental and simulation results of the system in summer provide a fundamental data and method for predicting the annual performance of the system in the future

Operational performance of a novel heat pump coupled with mini-channel PV/T and thermal panel in low solar radiation

Here we describe a heat pump system coupled with novel PV/T and thermal panels for space heating in low solar radiation conditions. Existing solar indirect-expansion systems connect the solar panels and evaporator of the heat pump in parallel with the heat storage tank. For our system these three components are instead connected in series, which can stabilize the temperature at the inlet of the evaporator and decrease the inlet temperature of the solar panels, leading to improved energy efficiency and the production of much more thermal energy. The experimental results of this system show that the average electrical, thermal and overall efficiency of the PV/T panels are 15.9%, 33.4% and 49.3%, respectively. The average thermal efficiency of the thermal panels is 60.4%, the COP of heat pump is 4.7 and the room temperature is constantly over 18 °C. Based on the experimental results, some improvements are analyzed. We conclude that this operating model can meet the requirement of space heating in low solar radiation environments

Biomechanical Analysis of the Fixation System for T-Shaped Acetabular Fracture

This study aims to evaluate the biomechanical mechanism of fixation systems in the most frequent T-shaped acetabular fracture using finite element method. The treatment of acetabular fractures was based on extensive clinical experience. Three commonly accepted rigid fixation methods (double column reconstruction plates (P × 2), anterior column plate combined with posterior column screws (P + PS), and anterior column plate combined with quadrilateral area screws (P + QS)) were chosen for evaluation. On the basis of the finite element model, the biomechanics of these fixation systems were assessed through effective stiffness levels, stress distributions, force transfers, and displacements along the fracture lines. All three fixation systems can be used to obtain effective functional outcomes. The third fixation system (P + QS) was the optimal method for T-shaped acetabular fracture. This fixation system may reduce many of the risks and limitations associated with other fixation systems

A two-dimensional hybrid with molybdenum disulfide nanocrystals strongly coupled on nitrogen-enriched graphene via mild temperature pyrolysis for high performance lithium storage

A novel 2D hybrid with MoS₂ nanocrystals strongly coupled on nitrogen-enriched graphene (MoS₂/NGg-C₃N₄) is realized by mild temperature pyrolysis (550 °C) of a self-assembled precursor (MoS₃/g-C₃N₄–H⁺/GO). With rich active sites, the boosted electronic conductivity and the coupled structure, MoS₂/NGg₋C₃N₄ achieves superior lithium storage performance

Effects of esketamine–sufentanil for patient-controlled intravenous analgesia in women following cesarean section: A randomized clinical trial

BackgroundPostoperative pain following cesarean section can cause maternal anxiety, limited ambulation, and even postpartum depression. In this study, we aimed to investigate the effects of esketamine for postoperative patient-controlled intravenous analgesia in women following cesarean section.MethodsOne hundred women were randomly assigned to two groups. The esketamine group received 1 mg⋅kg-1⋅d-1 of esketamine +1 µg⋅kg-1⋅d-1 of sufentanil for intravenous postoperative analgesia, and the control group received 1 µg⋅kg-1⋅d-1 of sufentanil for intravenous analgesia. The primary outcome was the pain intensity during the postoperative 24 h, and it was assessed using a visual analog scale (VAS). The secondary outcomes included hemodynamic parameters, total consumption of analgesics, blood loss, and drug-related side effects (hypotension, hypertension, bradycardia, nausea, and vomiting).ResultsThe VAS scores at rest were lower in the esketamine group than in the control group during the postoperative 6 h–24 h (p < 0.05), and the VAS scores at cough in the esketamine group were lower during the postoperative 4 h–24 h (p < 0.05). There were significant differences at blood loss during the postoperative 24 h (137.6 ± 33.0 vs 159.6 ± 41.3 mL, p = 0.004). Blood pressure and heart rate were greater in the esketamine group than in the control group during the postoperative 8 h–24 h (p < 0.05). The incidence of nausea and vomiting was significantly lower in the esketamine group than in the control group (4% vs 18%, p = 0.025).ConclusionThis study indicated that esketamine not only improved postoperative pain but also reduced postpartum blood loss and the incidence of nausea and vomiting in women undergoing cesarean section (registration number: ChiCTR2400082094).Systematic Review Registrationhttps://www.chictr.org.cn, Identifier ChiCTR240008209

The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the extended Baryon Oscillation Spectroscopic Survey and from the second phase of the Apache Point Observatory Galactic Evolution Experiment

The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in operation since July 2014. This paper describes the second data release from this phase, and the fourteenth from SDSS overall (making this, Data Release Fourteen or DR14). This release makes public data taken by SDSS-IV in its first two years of operation (July 2014-2016). Like all previous SDSS releases, DR14 is cumulative, including the most recent reductions and calibrations of all data taken by SDSS since the first phase began operations in 2000. New in DR14 is the first public release of data from the extended Baryon Oscillation Spectroscopic Survey (eBOSS); the first data from the second phase of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2), including stellar parameter estimates from an innovative data driven machine learning algorithm known as "The Cannon"; and almost twice as many data cubes from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous release (N = 2812 in total). This paper describes the location and format of the publicly available data from SDSS-IV surveys. We provide references to the important technical papers describing how these data have been taken (both targeting and observation details) and processed for scientific use. The SDSS website (www.sdss.org) has been updated for this release, and provides links to data downloads, as well as tutorials and examples of data use. SDSS-IV is planning to continue to collect astronomical data until 2020, and will be followed by SDSS-V.Comment: SDSS-IV collaboration alphabetical author data release paper. DR14 happened on 31st July 2017. 19 pages, 5 figures. Accepted by ApJS on 28th Nov 2017 (this is the "post-print" and "post-proofs" version; minor corrections only from v1, and most of errors found in proofs corrected

CausalCellSegmenter: Causal Inference inspired Diversified Aggregation Convolution for Pathology Image Segmentation

Deep learning models have shown promising performance for cell nucleus segmentation in the field of pathology image analysis. However, training a robust model from multiple domains remains a great challenge for cell nucleus segmentation. Additionally, the shortcomings of background noise, highly overlapping between cell nucleus, and blurred edges often lead to poor performance. To address these challenges, we propose a novel framework termed CausalCellSegmenter, which combines Causal Inference Module (CIM) with Diversified Aggregation Convolution (DAC) techniques. The DAC module is designed which incorporates diverse downsampling features through a simple, parameter-free attention module (SimAM), aiming to overcome the problems of false-positive identification and edge blurring. Furthermore, we introduce CIM to leverage sample weighting by directly removing the spurious correlations between features for every input sample and concentrating more on the correlation between features and labels. Extensive experiments on the MoNuSeg-2018 dataset achieves promising results, outperforming other state-of-the-art methods, where the mIoU and DSC scores growing by 3.6% and 2.65%.Comment: 10 pages, 5 figures, 2 tables, MICCA

Experimental investigation of a novel vertical loop-heat-pipe PV/T heat and power system under different height differences

For a novel vertical solar loop-heat-pipe photovoltaic/thermal system, the height difference between evaporator and condenser plays an important role in the heat transport capacity, which has significant impact on the solar thermal efficiency and parametrical optimization of this system. Therefore, based on the results derived from the authors’ previous analytical investigation and computer modelling studies, a prototype of this novel system was designed, constructed, and an experimental investigation under different height difference was undertaken to study the impact of height difference on the system performance. It was found that the relationship between the solar thermal efficiency of this vertical system and the height difference is nonlinear. In present study, the optimal height difference is around 1.1 m, which was selected as an optimal value for the following experimental investigations, and below 1.1 m, the PV module surface temperature decreased with the increase of the height difference. Furthermore, the transient solar thermal and electrical performance of this system with the selected optimal height difference were investigated under outdoor real weather condition. These results of this experimentation can help optimize the system construction and thus help to develop the high thermal performance and low-cost solar PV/T system for space heating and power generation