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Dealing with high transonic airflow at the outlet of a mixed-flow impeller is a challenging issue in research on the design of efficient and compact diffusers. A low aspect ratio and an adverse pressure gradient in the passage of the diffuser can lead to flow separation on the hub side of the bend and the suction side of the aft blade. Tandem blading can be used to attain flow control through an appropriate relative circumferential tandem position (λ). However, a comprehensive understanding of flow in a compact crossover tandem diffuser (CTD) requires further investigation. This study provides a detailed analysis of the mechanism of flow in a compact crossover baseline tandem diffuser (CBTD) as well as the influence of different values of λ on the structure of flow of the CTD. The findings show that the CBTD can suppress secondary flow separation on the hub side of the bend by reasonably distributing the radial load. We also found that a value of λ of 75% can delay the point of separation on the suction side of the aft blade over a wide range of spans, where this inhibits the corner separation vortex and improves the structure of flow and performance of the diffuser. We also preliminarily explore the impacts of excitation of full-span jet intensities with different values of λ on the corner separation vortex on the suction side of the aft blade and offer guidance for the design of a compact and efficient CTD. [ABSTRACT FROM AUTHOR]

The current work evaluates the effectiveness of the pressure-corrected osculating axisymmetric flows method in the design of hypersonic wavecatcher intakes with shape transition. The original osculating axisymmetric flows method, which is essentially used in waverider design, has drawbacks in accurately demonstrating the three-dimensional flowfield due to ignoring the cross-flow effects between the osculating planes. This negatively impacts the intake performance due to the presence of lateral pressure gradients. The pressure-corrected method takes into account these effects by incorporating lateral pressure gradient corrections into the original design methodology using cross-flow velocity information. This results in the generation of three-dimensional streamlines rather than the two-dimensional streamlines of the original method. The semirectangular-to-ellipse wavecatcher intake is selected as the subject of investigation, and the design procedure is reviewed. The characteristics of the wavecatcher intakes with a design point of Mach 6.0 are studied. Computational fluid dynamics analysis of pressure-corrected wavecatcher intakes is presented to assess the design technique. It is found that the initial conical shock impinges at the intake's entrance and the streamtube is completely captured. Furthermore, the comparison with the original wavecatcher intake indicates that the pressure-corrected wavecatcher intake demonstrated better performance in terms of total pressure recovery and flow uniformity. The wavecatcher intake with entrance-to-exit shapes transition showed higher performance than those with the same entrance and exit shapes. [ABSTRACT FROM AUTHOR]

Endwall-pulsed blowing (EPB) is studied for three different excitation waveforms to improve the aerodynamic performance of highly loaded compressors. Some important excitation parameters include the excitation frequency and momentum coefficient, which were analyzed in detail. The results of the EPB are compared with the endwall steady blowing (ESB) case. For EPBs with the three excitation waveforms (Waveforms sine, triangle and trapezoid), excitation frequencies that are equal to an integral multiple of the natural frequency of the vortex shedding are optimal and provide better performances than the ESB with the same time-mean momentum coefficient. Moreover, the EPBs of the three excitation waveforms have significant differences in their aerodynamic performance improvements. The optimal case is achieved by the EPB with Waveform triangle and provides a total pressure loss coefficient with a reduction of 25.64%. [ABSTRACT FROM AUTHOR]

Long driving times from hospice providers to patients lead to poor quality of care, which may exacerbate in rural and highly isolated areas of Appalachia. This study aimed to investigate geographic patterns of pediatric hospice care across Appalachia. Using person-level Medicaid claims of 1,788 pediatric hospice enrollees who resided in the Appalachian Region between 2011 and 2013. A database of boundaries of Appalachian counties, postal addresses of hospices, and population-weighted county centroids of residences of hospice enrollees driving times from the nearest hospices were calculated. A choropleth map was created to visualize rural/urban differences in receiving hospice care. The average driving time from hospice to child residence was 28 minutes (SD = 26). The longest driving time was in Eastern Kentucky—126 minutes (SD = 32), and the shortest was in South Carolina—11 min (SD = 9.1). The most significant differences in driving times between rural and urban counties were found in Virginia 28 (SD = 7.5) and 5 minutes (SD = 0), respectively, Tennessee—43 (SD = 28) and 8 minutes (SD = 7), respectively; and West Virginia—49 (SD = 30) and 12 minutes (SD = 4), respectively. Many pediatric hospice patients reside in isolated counties with long driving times from the nearest hospices. State-level policies should be developed to reduce driving times from hospice providers. [ABSTRACT FROM AUTHOR]

An important challenge in industrial laser ablation is laser-induced damage. In this study, reduced damage was achieved through the transition of the laser distribution from a Gaussian beam to a top-hat beam using diffractive optical elements (DOE), which overcome inhomogeneous irradiation. The higher peak fluence of a Gaussian beam far exceeded the ablation threshold and led to severely melted silicon at a higher depth covering the polished texture. The top-hat beam, with uniform irradiation, had a superior ablation characteristic and created a uniform square opening with the shallow melted silicon in the lift-off process. Thus, its effective minor carrier lifetime was 15.35% less at an ablated area fraction of 2% after re-passivation because of the decreased damage. After optimizing the ablation pattern with a top-hat beam, the local contacts improved the average open-circuit voltage (Voc) and short-circuit current (Isc) values of the cells due to the decreased damage and the uniform openings, but the damage induced by a Gaussian beam was too deep and can be partly restored under back surface field (BSF) formation. The overall increment in Isc and Voc enhanced the average efficiency by 0.05% of the absolute value for the PERC cells and 0.03% of the absolute value for bi-facial PERC cells. [ABSTRACT FROM AUTHOR]

Currently, little is known about how geographic information systems (GIS) has been utilized to study end-of-life care in pediatric populations. The purpose of this review was to collect and examine the existing evidence on how GIS methods have been used in pediatric end-of-life research over the last 20 years. Scoping review method was used to summarize existing evidence and inform research methods and clinical practice was used. The Preferred Items for Systematic Reviews and Meta-Analyses for Scoping Reviews (PRISMA) was utilized. The search resulted in a final set of 17 articles. Most studies created maps for data visualization and used ArcGIS as the primary software for analysis. The scoping review revealed that GIS methodology has been limited to mapping, but that there is a significant opportunity to expand the use of this methodology for pediatric end-of-life care research. [ABSTRACT FROM AUTHOR]

Programmed cell death (PCD) induction is a promising strategy for killing gastric cancer cells. In this study, we investigated the effects of chrysophanol on apoptosis and ferroptosis in gastric cancer cells. Chrysophanol in concentrations ranging from 0 to 100 μM were used to treat GES‐1, HGC‐27 and AGS cells. Cell counting kit‐8 assay, colony formation assay, 5‐ethynyl‐2′‐deoxyuridine staining, flow cytometry, JC‐1 probe insertion, dihydroethidium staining and western blotting were performed. The effects of chrysophanol on gastric cancer cells were evaluated in vivo using a xenograft mouse model. Chrysophanol had no cytotoxic effects on GES‐1 cells. Chrysophanol with concentrations higher than 25 μM inhibited gastric cancer cell colony formation and proliferation. Chrysophanol induces gastric cancer cell apoptosis in a dose‐dependent manner, accompanied by mitochondrial membrane potential dysfunction and cytochrome c release. Additionally, chrysophanol increased the levels of reactive oxygen species, total iron, and Fe2+ in HGC‐27 and AGS cells, in a dose‐dependent manner. Treatment of cells with the ferroptosis inhibitor ferrostatin‐1 attenuated the effects of chrysophanol on cell survival and the expression of ferroptosis markers SLC7A11 and GPX4. Screening by GEO software indicated that the mTOR signalling pathway is possibly regulated by chrysophanol. Furthermore, mTOR overexpression significantly reversed the inhibitory effects of chrysophanol on gastric cancer cells. In gastric cancer xenograft mouse models, chrysophanol treatment inhibited tumour growth and downregulated SLC7A11 and GPX4. Chrysophanol induces apoptosis and ferroptosis, making it a potential candidate for killing gastric cancer cells. The beneficial effects of chrysophanol may be attribute to the targeted regulation of mTOR. [ABSTRACT FROM AUTHOR]

The tip-leakage vortex, as the dominant coherent structure of the blade tip of a compressor, is an important source of losses in centrifugal compressor rotors; it limits the stall margin and can even cause compressor surge. The miniaturization of mechanical components has attracted significant attention; however, the miniaturization of compressors—particularly centrifugal compressors—further increases the adverse effects of the tip-leakage vortex. This study sought to establish a new passive unsteady flow-control method for a micro centrifugal compressor using equal-circumferential-spacing through-holes on its casing. This approach fully exploits the unsteady characteristics of the flow field. A numerical study of the coherent characteristics of the blade tip was carried out using dynamic mode decomposition. The numerical conclusions were then applied to a physical system. The results of experimental tests of this system indicate that the improved flow-control method can increase the maximum efficiency and stall margin of the compressor by 2.5% and 9.0%, respectively, and it can also increase the maximum pressure ratio. [ABSTRACT FROM AUTHOR]

Small space interconnection technology (SSIT) has been utilized in solar panels recently. The application of this technology can further increase the module efficiency. However, higher power decay after long-time operation may occur due to additional risk. Therefore, in this paper, damp heat (DH), thermal cycle (TC), UV irradiation and humidity freezing (HF) tests were utilized to study the weatherability performance of SSIT-based high-density solar panels fabricated with cells cut by two different techniques. The achieved data suggest that the novel high-density modules with small space between cells have good reliability in various weather conditions. The novel low-damage laser-induced cutting technique is beneficial for the improvement of module reliability.

Negative space welding technology (NSWT) is a newly adopted advanced technology for high-density solar panels. The benefit of this technology is its capability to improve the efficiency of panels. However, the introduction of a new technology or material may affect the original reliability. Some unexpected power loss may occur during its operation in different environments. Hence, in this work, damp heat (DH), thermal cycle (TC), UV irradiation and humidity freezing (HF) tests were utilized to evaluate the weatherability of NSWT-based panels fabricated with silicon cells cut by two different techniques. It is suggested by our results that these new panels with negative space between cells have good weatherability both in damp heat, dry heat and UV irradiation condition. The novel low-damage laser-induced cutting technique is beneficial for the improvement of module reliability.