Soundness of additively manufactured parts depends on a lot of process and geometrical parameters. A wrong process design leads to defects such as lack of fusion or keyhole porosity that have a ...detrimental effect on the mechanical properties of the printed parts. Process parameter optimization is thus a formidable challenge that requires in general a huge amount of experimental data. Among the others, heat source power and scan speed are the most defects-affecting parameters to be optimized. The energy density is used in literature to quantify their combination. Unfortunately, in different works it was demonstrated that it fails if used as design parameter mainly because it does not take into account the material properties and the interaction between heat source and the powder bed. In this contribution, a modified volumetric energy density equation that takes into account the powder-heat source interaction to optimize the combination of power-scan speed values for porosity assessment in powder bed fusion process design is proposed and verified on both AlSi10Mg alloy and Maraging steel 300.
Previous measurements of stellar properties for K2 stars in the Ecliptic Plane Input Catalog largely relied on photometry and proper motion measurements, with some added information from available ...spectra and parallaxes. Combining Gaia DR2 distances with spectroscopic measurements of effective temperatures, surface gravities, and metallicities from the Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) DR5, we computed updated stellar radii and masses for 26,838 K2 stars. For 195,250 targets without a LAMOST spectrum, we derived stellar parameters using random forest regression on photometric colors trained on the LAMOST sample. In total, we measured spectral types, effective temperatures, surface gravities, metallicities, radii, and masses for 222,088 A, F, G, K, and M-type K2 stars. With these new stellar radii, we performed a simple reanalysis of 299 confirmed and 517 candidate K2 planet radii from Campaigns 1-13, elucidating a distinct planet radius valley around 1.9 R⊕, a feature thus far only conclusively identified with Kepler planets, and tentatively identified with K2 planets. These updated stellar parameters are a crucial step in the process toward computing K2 planet occurrence rates.
HPV-positive cancer is strongly immunogenic tumor which induces cell type response in surrounding microenvironment. Systemic inflammation is generally accompanied by cancer disease and it weakens ...cell response and negatively influences organism reaction to cancer
The aim of present study was to compare laboratory parameters of the immune system: leukocyte count (WBC), neutrophil count (Neut) and lymphocyte count (Lym), monocyte count (Mono), C-reactive protein (CRP), Interleukine 6 (Il-6), in patients with HPV-positive and HPV-negative OPC.
75 patients were treated with curative intent with radiotherapy alone (32 %) or combined with platinum-based chemotherapy (68%). There were 47% patients with T1/2 and 53% with T3/4 of primary tumor stage and 44% and 56% of patients with N0 and N+ nodal stage disease, respectively. Complete blood counts (CBC), C-reactive protein (CRP) and Il-6 were estimated in blood or serum before and after the treatment. HPV DNA was determined in plasma by QPCR method.
In patients with HPV-negative OPC WBC count (p=0,006 median: 6,88 vs 5,69), Lym count (p=0,02 median: 1,96 vs 1,49) and CRP (p=0,0001 median: 5,88 vs 1,35 mg/dl) was higher than for HPV-positive OPC before treatment. Additionally, in patients with HPV-negative OPC WBC count (p=0,03 median: 5,53 vs 4,17), Lym count (p=0,02 median: 0,69 vs 0,44), Mono count (p=0,003 median: 0,58 vs 0,43) and Il-6 (p=0,05 median: 25,53 vs 11,65 pg/ml) was higher than for HPV-positive OPC after therapy. Before treatment significantly longer overall survival (OS) for patients with low WBC count (p=0,001)(Fig.1), low concentration of CRP (p=0,0001) (Fig. 2) and Il-6 (p=0,01) was also found.
Inflammation processes are more severe in HPV-negative OPC. Low levels of inflammatory indicators like WBC count, Lym count, CRP, Il-6 may be associated with longer OS in this group of patients. Systemic inflammation reflects host reaction on cancer, characterized by a significant weakness of cellular immunity. It is more characteristic for patients with HPV–negative OPC
The Event Horizon Telescope (EHT) collaboration has recently released the first image of a black hole (BH), opening a new window onto tests of general relativity in the strong field regime. In this ...paper, we derive constraints on the nature of M87* (the supermassive object at the center of the galaxy M87), exploiting the fact that its shadow appears to be highly circular, and using measurements of its angular size. We first consider the simple case where M87* is assumed to be a Kerr BH. We find that the inferred circularity of M87* excludes Kerr BHs with observation angle θobs≳45° for dimensionless rotational parameter 0.95≲a*≤1 whereas the observation angle is unbounded for a*≲0.9. We then consider the possibility that M87* might be a superspinar, i.e., an object described by the Kerr solution and spinning so fast that it violates the Kerr bound by having |a*|>1. We find that, within certain regions of parameter space, the inferred circularity and size of the shadow of M87* do not exclude the possibility that this object might be a superspinar.
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•Factors affecting the efficiency of TiO2 photocatalyst were discussed.•Modified techniques used to improve the efficiency of TiO2-Based Photocatalysts.•Different operating parameters ...affect the photocatalytic hydrogen production process.•TiO2-Based Photocatalysts used for photocatalytic solar hydrogen production.•Challenges and future perspective for designing a good photocatalyst was highlighted.
Photocatalytic hydrogen generation via water splitting is a sustainable, renewable, and promising technology to produce green and clean hydrogen fuel by disassociating water into H2 and O2 using TiO2 photocatalyst, and sunlight with negligible impact on the environment, which can fulfill the future requirements of energy. TiO2-based photocatalysts are one of the most effective and widely used photocatalysts for photocatalytic hydrogen production due to their high photostability, abundance, high efficiency, non-toxicity, and low cost. However, TiO2 as a common photocatalyst cannot be easily applied to photocatalysis due to its wide bandgap energy that can only be activated under UV light, which occupies around 2–5% of the solar spectrum and the higher recombination rate of the photogenerated charge carriers before migrating to the surface to split water that restricted its photocatalytic performance. For that, factors such as surface area, particle size, and calcination temperature that affect the photocatalytic activity of TiO2 were highlighted. Additionally, the rational strategies such as doping, composite structure, dyes sensitization, defects engineering, and others that are used in enhancing their activities are described in detail. Importantly, the investigation showed that various parameters such as pH, sacrificial reagent, light intensity, catalyst, cocatalyst loading and catalyst deactivation, have great effects on photocatalytic hydrogen production over TiO2-based photocatalysts. Through reviewing the important state-of-the-art advances on this topic, this comprehensive review may provide new opportunities for designing and constructing highly effective TiO2-based photocatalysts for other applications in photocatalysis.
Unambiguous identification of the superconducting order parameter symmetry in Sr2RuO4 has remained elusive for more than a quarter century. While a chiral p-wave ground state analogue to superfluid ...3He-A was ruled out only very recently, other proposed triplet-pairing scenarios are still viable. Establishing the condensate magnetic susceptibility reveals a sharp distinction between even-parity (singlet) and odd-parity (triplet) pairing since the superconducting condensate is magnetically polarizable only in the latter case. Here field-dependent 17O Knight shift measurements, being sensitive to the spin polarization, are compared to previously reported specific heat measurements for the purpose of distinguishing the condensate contribution from that due to quasiparticles. We conclude that the shift results can be accounted for entirely by the expected field-induced quasiparticle response. An upper bound for the condensate magnetic response of <10% of the normal state susceptibility is sufficient to exclude all purely odd-parity candidates.
This work revisits the statistics of observed tropical cyclone outer size in the context of recent advances in our theoretical understanding of the storm wind field. The authors create a new dataset ...of the radius of 12 m s−1 winds based on a recently updated version of the QuikSCAT ocean wind vector database and apply an improved analytical outer wind model to estimate the outer radius of vanishing wind. The dataset is then applied to analyze the statistical distributions of the two size metrics as well as their dependence on environmental parameters, with a specific focus on testing recently identified parameters possessing credible theoretical relationships with tropical cyclone size. The ratio of the potential intensity to the Coriolis parameter is found to perform poorly in explaining variation of size, with the possible exception of its upper bound, the latter of which is in line with existing theory. The rotating radiative–convective equilibrium scaling of Khairoutdinov and Emanuel is also found to perform poorly. Meanwhile, mean storm size is found to increase systematically with the relative sea surface temperature, in quantitative agreement with the results of a recent study of storm size based on precipitation area. Implications of these results are discussed in the context of existing tropical climate theory. Finally, an empirical dependence of the central pressure deficit on outer size is found in line with past work.
This article presents an accurate computational technique for estimating the photovoltaic (PV) cell parameters from experimental measurements of the current-voltage (I–V) characteristics. The ...technique is based on using various evolutionary algorithms (EAs) and the double-diode eight-parameter cell model to precisely estimate unknown parameters. The proposed technique is implemented to extract the PV cell parameters of different manufacturer's modules by minimising the summation of absolute square errors between theoretical and measured I–V output characteristics obtained under different irradiation levels. The effectiveness and robustness of the proposed technique are demonstrated via a comparative assessment of the measured output I–V characteristics and those obtained by computer simulation, using Matlab SIMSCAPE library components. The good agreement obtained between theoretical and experimental results endorses the proposed approach to determine precisely the PV parameters required for power system studies. The proposed technique is useful power system studies with penetration of photovoltaic sources.
This paper proposes a novel high-order passive filter, i.e., series-parallel-resonant LCL (SPRLCL) filter, for single-phase half-bridge active power filters. The proposed SPRLCL filter consists of a ...series resonance introduced by adding a small inductor to the capacitor branch loop and a parallel resonance by paralleling a small capacitor with the gird-side inductor. Three design methods are proposed to fine tune the parameters of the SPRLCL filter. Design method I and method II enable the SPRLCL filter to attenuate more switching-frequency and double switching-frequency current harmonics than LCL or LLCL filters, while with design method III, the SPRLCL filter can be more robust against filter parameter variations. In order to achieve a better damping performance and facilitate the design of active damping control, the dominant resonance frequency of the proposed filter is set at one-third of the system sampling frequency. Based on this, a comprehensive parameter design process of the SPRLCL filter is presented, where the variation of source inductance is also considered. A proportional plus repetitive current-loop controller is designed to ensure system control stability and satisfactory harmonic compensation. Simulation and experimental results are finally presented to validate the feasibility of the theoretical analysis.
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