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A numerical investigation has been conducted to study the convective heat transfer enhancement and friction loss behaviors for turbulent flow by using arrays of differently shaped ribs combined with delta-winglet vortex generators (DWVGs) pair on the absorber plate of a solar air heater. Four transverse vortex generators arrays, i.e., 90° continuous ribs, 90° truncated ribs, 60° V-shaped continuou
The difficult manufacturing of helical baffles hinders the widespread application of the enhancement technology and the shortcut leakage between adjacent baffles impairs the enhancement effects. To solve these two issues, the promising anti-leakage and easy-to-manufacture helical baffles with small inclined angle and folded structure are proposed, which can be produced by 2D laser cutting and simp
In this paper, effects of four different hole configurations on film cooling performance and particle deposition are investigated numerically on a curved surface. The RNG k-ε turbulence model is used, and the discrete phase model is developed by user-defined functions. The particle deposition on the curved surface is analyzed by calculated results of capture and impact efficiencies. Results show t
Objectives There is evidence that emergency department (ED) crowding is associated with increased mortality, however large multicenter studies of high quality are scarce. In a prior study, we introduced a proxy-measure for crowding that was associated with increased mortality. The national registry SVAR enables us to study the association in a more heterogenous group of EDs with more recent data.
In this study, the effect of axial heat conduction on thermal performance in a zigzag channel printed circuit heat exchanger (PCHE) with supercritical liquefied natural gas as the working fluid is studied by a numerical method under different conditions. The influence factors include Reynolds number, operating pressure, inlet temperatures of the cold side, and wall thermal conductivity. The result
Predation is a well-studied driver of ecological selection on prey traits, which frequently drives divergence in anti-predator performance across environments that vary in predation risk. However, predation also alters prey mortality regimes, where low predation risk often results in higher prey densities and consequently higher intensities of intraspecific resource competition. In addition, preda
Background: Esophageal atresia (EA) affects around 2.3–2.6 per 10,000 births world-wide. Infants born with this condition require surgical correction soon after birth. Most survival studies of infants with EA are locally or regionally based. We aimed to describe survival across multiple world regions. Methods: We included infants diagnosed with EA between 1980 and 2015 from 24 birth defects survei
Ferroelectric memories based on hafnium oxide are an attractive alternative to conventional memory technologies due to their scalability and energy efficiency. However, there are still many open questions regarding the optimal material stack and processing conditions for reliable device performance. Here, we report on the impact of the sputtering process conditions of the commonly used TiN top ele
A steam methane reforming reactor is a key equipment in hydrogen production, and numerical analysis and process control can provide a critical insight into its reforming mechanisms and flexible operation in real engineering applications. The present paper firstly studies the transport phenomena in an industrial-scale steam methane reforming reactor by transient numerical simulations. Wall effect a
Templated electrochemical growth in nanoporous alumina can be used to fabricate nanowires with applications in magnetic storage devices, hydrogen sensors, and electrocatalysis. It is known that nanowires, grown in such templates, are strained. The strain in nanoscale materials can influence their performance in applications such as catalysts and electronic devices. However, it is not well establis
Recently diverged species often show incomplete reproductive isolation and subsequently experience hybridization and introgression. The plant genus Mimulus includes many such examples of closely related taxa that prove useful for studying incipient speciation. However, Sandstedt et al. show that in contrast to other Mimulus species, species of the M. tilingii complex are characterized by strong po
This study presents how sequential infiltration synthesis of trimethyl aluminium and water into a carbohydrate-based block copolymer was used to enable pattern transfer of 6 nm half-pitch horizontal cylinders into silicon. Specular neutron reflectometry measurements of poly(styrene)-block-maltoheptaose self-assembled into horizontal cylinders indicate an increasing content of alumina after each se
Modeling diffusion of nonspherical particles presents an unsolved and considerable challenge, despite its importance for the understanding of crowding effects in biology, food technology and formulation science. A common approach in experiment and simulation is to map nonspherical objects on effective spheres to subsequently use the established predictions for spheres to approximate phenomena for
Through the optimization of the perovskite precursor composition and interfaces to selective contacts, we achieved a p-i-n-type perovskite solar cell (PSC) with a 22.3% power conversion efficiency (PCE). This is a new performance record for a PSC with an absorber bandgap of 1.63 eV. We demonstrate that the high device performance originates from a synergy between (1) an improved perovskite absorbe
Catalysts are materials that accelerate the rate of a desired chemical reaction. As such, they constitute an integral part in many applications ranging from the production of fine chemicals in chemical industry to exhaust gas treatment in vehicles. Accordingly, it is of utmost economic interest to improve catalyst efficiency and performance, which requires an understanding of the interplay between
Researchers have measured superfluid helium’s full dispersion spectrum, explaining discrepancies in previous studies and constraining theories of superfluidity.
γ-CoV2O6 is a quasi-one-dimensional spin-3/2 magnet that possesses two distinct magnetic orders at low temperatures with propagation vectors k1=(½,0,0) and k2=(¼ + δh, δk, - ¼ + δl), respectively. Here we use muon spin relaxation and rotation to reveal the thermodynamics of the magnetic phase separation in this compound. In the paramagnetic (PM) region, short-range correlated spin clusters emerge
By measuring a linear response function directly, such as the dynamic susceptibility, one can understand fundamental material properties. However, a fresh perspective can be offered by studying fluctuations. This can be related back to the dynamic susceptibility through the fluctuation–dissipation theorem, which relates the fluctuations in a system to its response, an alternate route to access the
Ultrafast, light-induced dynamics in copper-zinc-tin-sulfide (CZTS) photovoltaic nanoparticles are investigated through a combination of optical and x-ray transient absorption spectroscopy. Laser-pump, x-ray-probe spectroscopy on a colloidal CZTS nanoparticle ink yields element-specificity, which reveals a rapid photo-induced shift of electron density away from Cu-sites, affecting the molecular or
A numerical method is utilized in this paper to study the effects of varying divider inclination angle on the flow structure and heat transfer characteristics in a ribbed two-pass channel for Reynolds number varying from 10,000 to 50,000. The studied divider inclination angles are −3°,−2°,−1°,0°, +1°, +2° and +3°. The ribs have an orientating angle of 45°. The results show that the heat transfer i
