•Solar powered organic Rankine-vapor compression ice maker is researched.•The parabolic trough collectors are selected in the ice maker.•Four working fluids are selected and evaluated to identify ...most suitable one.
To develop the organic Rankine cycle/vapor compression cycle (ORC/VCC) ice maker driven by solar energy, a thermodynamic model was developed, and four working fluids of R123, R245fa, R600a and R600 were selected and evaluated to identify suitable working fluids which may yield high system efficiencies. Besides, the effects of generation temperature and condensation temperature on the system performance were also analyzed. In terms of power efficiency and expander size, R600 and R600a are more suitable working fluids for ORC. Also, R600a and R600 are more appropriate working fluids for VCC in terms of pressure ratio and coefficient of performance. In terms of overall efficiency and ice production per square meter collector per day, R123 is most suitable working fluid for ORC/VCC. The generation temperature and condensation temperature have important effects on overall efficiency and ice production. There is always an optimal generation temperature at which overall efficiency and ice production can achieve the maximum values, while the generation temperature can be controlled by changing the mass flow rate of working fluid for ORC. In addition, the system performance and payback period should be comprehensively considered so as to decide to adopt air cooled or water cooled condenser due to having different condensation temperature.
Abstract
Using the observations of the high-energy detector of the Hard X-ray Modulation Telescope (Insight-HXMT) for Scorpius X-1 from 2017 to 2020, we search for hard X-ray tails in the X-ray ...spectra in ∼30–200 keV. The hard X-ray tails are found throughout the
Z
-track on the hardness–intensity diagram, and the detected hard X-ray tails become hard and weak from the horizontal branch (HB), through the normal branch (NB), to the flaring branch (FB). Comparing the hard X-ray spectra of Insight-HXMT between Cyg X-1 and Sco X-1, it is concluded that the hard X-ray spectrum of Cyg X-1 shows a high-energy cutoff, implying a hot corona in it, but the high-energy cutoff is not seen in the hard X-ray spectrum of Sco X-1. From fitting the broadband spectrum of Sco X-1 in ∼2–200 keV, it is proposed that the hard X-ray tails in the HB and NB can be explained by the overall Comptonization COMPTB model, suggesting that the hard X-ray tails could have resulted from the Comptonization of the photons from the neutron star (NS) surface by the thermal electrons in the region between the NS and the disk and the energetic electrons in the freefall toward the NS in the converging flow onto the NS. However, this model cannot be responsible for the hard X-ray tails in the FB. Further study on the FB hard X-ray tails is needed.
Abstract
Virtual testing is getting more and more attention in the field of vehicle detection. In order to improve the evaluation accuracy of virtual test data under the condition of far side ...occupant protection, the paper studies the evaluation method of remote virtual test data accuracy. First, the dynamic responses of 11 simulation and test data are determined by analyzing the basic data under remote conditions. Then, based on CORA and ISO_ The measurement method of TS18571 is used to evaluate the correlation, and the error analysis method is used to analyze the responses with differences in the correlation evaluation results. Finally, the conclusion of the precision evaluation of CORA and ISO measurement methods is obtained through experimental research.
The black hole X-ray binary source 4U 1543–47 experienced a super-Eddington outburst in 2021, reaching a peak flux of up to ∼1.96 × 10 −7 erg cm −2 s −1 (∼8.2 Crab) in the 2−10 keV band. Soon after ...the outburst began, it rapidly transitioned into the soft state. Our goal is to understand how the accretion disk structure deviates from a standard thin disk when the accretion rate is near Eddington. To do so, we analyzed spectra obtained from quasi-simultaneous observations conducted by the Hard X-ray Modulation Telescope (Insight-HXMT), the Nuclear Spectroscopic Telescope Array ( NuSTAR ), and the Neil Gehrels Swift Observatory ( Swift ). These spectra are well fitted by a model comprising a disk, a weak corona, and a reflection component. We suggest that the reflection component is caused by disk self-irradiation, that is by photons emitted from the inner disk that return to the accretion disk surface as their trajectories are bent by the strong gravity field. In this scenario, the best-fitting parameters imply that the reflected flux represents more than half of the total flux. Using general relativistic ray-tracing simulations, we show that this scenario is viable when the disk becomes geometrically thick, with a funnel-like shape, as the accretion rate is near or above the Eddington limit. In the specific case of 4U 1543–47, an angle ≳45 deg between the disk surface and the equatorial plane can explain the required amount of self-irradiation.
Based on the effective medium approximation and the fractal theory for the description of nanoparticle cluster and its radial distribution, a method for modeling the effective thermal conductivity of ...“nanofluid” is established. The size effect and the surface adsorption of nanoparticles are taken into considerations. The proposed fractal model is discussed in detail for its application, and it predicts quite well with our recent measuring data for dilute suspensions of metallic oxide nanoparticles.
ABSTRACT
We studied the transient Galactic black hole candidate MAXI J0637−430 with data from Insight-HXMT, Swift, and XMM–Newton. The broad-band X-ray observations from Insight-HXMT help us ...constrain the power-law component. MAXI J0637–430 is located at unusually high Galactic latitude; if it belongs to the Galactic thick disc, we suggest a most likely distance ≲7 kpc. Compared with other black hole transients, MAXI J0637–430 is also unusual for other reasons: a fast transition to the thermal dominant state at the start of the outburst; a low peak temperature and luminosity (we estimate them at ≈0.7 keV and ≲0.1 times Eddington, respectively); a short decline time-scale; a low soft-to-hard transition luminosity (≲0.01 times Eddington). We argue that such properties are consistent with a small binary separation, short binary period (P ∼ 2 h), and low-mass donor star (M2 ∼ 0.2 M⊙). Moreover, spectral modelling shows that a single disc blackbody component is not a good fit to the thermal emission. Soft spectral residuals, and deviations from the standard $L_{\rm disc} \propto T_{\rm in}^4$ relation, suggest the need for a second thermal component. We propose and discuss various scenarios for such component, in addition to those presented in previous studies of this source. For example, a gap in the accretion disc between a hotter inner ring near the innermost stable orbit, and a cooler outer disc. Another possibility is that the second thermal component is the thermal plasma emission from an ionized outflow.
Considering the continuous shortening of automobile R & D cycle, mathematical methods have been more used in automotive aerodynamic optimization design for their capability to fit the law and ...calculate the optimal results. In this paper, the deformation software, fluid analysis software and optimization software are connected to build an automatic aerodynamics optimization platform of automotive shape. Based on the RBF model, the automatic aerodynamic optimization for a SUV is completed with the front windshield angle, rear windshield angle, engine cover angle, approach angle and departure angle as design parameters and the drag coefficient as design objective. The drag coefficient of the optimal model is 9.40% lower than that of the initial model, and remarkable drag reduction effect is achieved.
For the purpose of realizing fast and effective detection of defects in woven fabric, and in consideration of the inherent characteristics of fabric texture, i.e., periodicity and orientation, a new ...approach for fabric texture analysis, based on the modern spectral analysis of a time series rather than the classical spectral analysis of an image, is proposed in this paper. Traditionally, a power spectral estimated by a two-dimensional Fast Fourier transformation (FFT) is usually employed in the detection of fabric defects, which involves a large computational complexity and a relatively low accuracy of spectral estimation. To this effect, this paper makes a one-dimensional power spectral density (PSD) analysis of the fabric image via a Burg-algorithm-based Auto-Regressive (AR) spectral estimation model, and accordingly extracts features capable of effectively differentiating normal textures from defective ones. A support vector data description is adopted as a detector in order to deal with defect detection, a typical task of one-class classification. Experimental results for the detection of defects from several fabric collections with different texture backgrounds indicate that a low false alarm rate and a low missing rate can be simultaneously obtained with less computational complexity. Comparison of the detection results between the AR model and the FFT method confirms the superiority of the proposed method.
Summary
Background Paraneoplastic pemphigus (PNP) is an autoimmune mucocutaneous disease. We previously reported that B cells in a Castleman tumour associated with PNP produced autoantibodies. ...However, it is uncertain whether the production of autoantibodies from the associated tumour is a common mechanism in PNP.
Objectives To investigate autoantibody production in a thymoma and a follicular dendritic cell sarcoma that were excised from two patients with PNP.
Methods Tumour cells were cultured, and their surface markers were identified. Indirect immunofluorescence, immunoblotting and enzyme‐linked immunosorbent assay (ELISA) using culture media from the tumours were used to detect PNP autoantibodies.
Results B cells with markers (CD22+, surface membrane IgG+ and surface membrane IgM+) of mature B lymphocytes constituted a proportion of cultured tumour cells in both tumours. Western blot showed that the medium from both the thymoma and the follicular dendritic cell sarcoma cells recognized 190‐kDa periplakin and 210‐kDa envoplakin bands of human epithelial proteins as well as recombinant linker regions of periplakin, envoplakin, desmoplakin and bullous pemphigoid antigen 1. ELISA was positive for antidesmoglein 3 antibody.
Conclusions The presence and localization in tumours of B‐lymphocyte clones against proteins of the plakin family and desmoglein 3 in skin may not be confined to PNP with Castleman disease, but is possibly a common mechanism in PNP associated with various tumours.
High accuracy tire modeling is essential to study the automotive fatigue-durability, handling-stability, and NVH performance in the virtual proving ground. Compared with other tire models, CDTire/3D ...can be directly used in multi-body dynamics simulation, and its linearized version can be adopted in road noise analysis. In consideration of its high generality for cost saving, CDTire/3D has an extensive engineering application prospective in the automotive industry. It is the critical technique to accomplish high-efficiency and high-precision CDTire/3D modeling by investigating the mechanical mechanism of tire and the influence of parameters on all test conditions, based on which a parameter identification strategy is conducted in this paper. The effectiveness of the strategy is verified by a tire modeling case.
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