Vertical Energy Research Articles

Acid-Base Properties of Cis-Vacant Montmorillonite Edge Surfaces: A Combined First-Principles Molecular Dynamics and Surface Complexation Modeling Approach.

Montmorillonite layer edge surfaces have pH-dependent properties, which arises from the acid-base reactivity of their surface functional groups. Edge surface acidity (with intrinsic reaction equilibrium constant, pKa) is a chemical property that is affected by crystal structure. While a cis-vacant structure predominates in natural montmorillonites, prior molecular-level studies assume a centrosymmetric trans-vacant configuration, which potentially leads to an incorrect prediction of montmorillonite acid-base surface properties. We computed intrinsic acidity constants of the surface sites of a montmorillonite layer with a cis-vacant structure using the first-principles molecular dynamics-based vertical energy gap method. We evaluated pKa values for both non-substituted and Mg-substituted layers on common edge surfaces (i.e., surfaces perpendicular to [010], [01̅0], [110], and [1̅1̅0] crystallographic directions). The functional groups ≡Si(OH), ≡Al(OH2)2/≡Al(OH)(OH2), and ≡SiO(OH)Al sites on surfaces perpendicular to [010] and [01̅0] and ≡Si(OH)U, ≡Si(OH)L, ≡Al(OH2), and ≡Al(OH2)2 on surfaces perpendicular to [110] and [1̅1̅0] determine the proton reactivity of non-substituted cis-vacant edge surfaces. Moreover, the structural OH sites on edge surfaces had extremely high pKa values, which do not show reactivity at a common pH. Meanwhile, Mg2+ substitution results in an increase in pKa values at local or adjacent sites, in which the effect is limited by the distance between the sites. A surface complexation model was built with predicted pKa values, which enabled us to predict surface properties as a function of pH and ionic strength. Edge surface charge of both trans- and cis-vacant models has little dependence on Mg2+ substitutions, but the dependence on the crystal plane orientation is strong. In particular, at pH below 7, edge surfaces are positively or negatively charged depending on their orientation. Implications of these findings on contaminant adsorption by smectites are discussed.

Dynamic Mechanisms Associated with the Structure and Evolution of Roll Vortices and Coherent Turbulence in the Hurricane Boundary Layer: A Large Eddy Simulation During the Landfall of Hurricane Harvey

Roll vortices are a series of large-scale turbulent eddies that nearly align with the mean wind direction and prevail in the hurricane boundary layer. In this study, the one-way nested WRF-LES model simulation results from Li et al. (J Atmos Sci 78(6):1847–1867, https://doi.org/10.1175/JAS-D-20-0270.1, 2021) are used to examine the structure and generation mechanism of roll vortices and associated coherent turbulence in the hurricane boundary layer during the landfall of Hurricane Harvey from 00 UTC 25 to 18 UTC 27 August 2017. Results indicate that roll vortices prevail in the hurricane boundary layer. The intense roll vortices and associated large turbulent eddies above them (at a height of ~ 200 to 3000 m) accumulate within a hurricane radius of 20–40 km. Their intensity is proportional to hurricane intensity during the simulation period. Before and during hurricane landfall, strong inflow convergence leads to horizontal advection of roll vortices throughout the entire hurricane boundary layer. Combined with the strong wind shear, the strongest roll vortices and associated large turbulent eddies are generated near the eyewall with suitable thermodynamic (Richardson number at around − 0.2 to 0.2) and dynamic conditions (strong negative inflow wind shear). After landfall, the decayed inflow weakens the inflow convergence and quickly reduces the strong roll vortices and associated large turbulent eddies. Diagnosis of vertical turbulent kinetic energy indicates that atmospheric pressure perturbation, caused by horizontal convergence, transfers the horizontal component of turbulence to the vertical component with a mean wavelength of about 1 km. The buoyancy term is weak and negative, and the large turbulent eddies are suppressed.

Prospects for the application of a small wind power device with a vertical axis in the Jizzakh region

In recent years, renewable energy sources, especially wind energy, have been widely used around the world. Big projects are being implemented in Uzbekistan for the development of wind energy in the next decade. Large wind power plants are being built in different regions of the country such as Navoi, Bukhara, and Karakalpakstan. In these wind power plants, horizontal type wind energy devices are mainly used for the production of electricity. Horizontal-axis wind energy devices are used not only in the production of large capacities, but also in providing local consumers with small capacities. However, the share of electricity generation or supply of local consumers with the help of small vertical axis wind energy devices is much smaller. In this article, analyzing the potential of wind energy in Jizzakh region, the prospects of using small vertical wind energy devices are theoretically researched.

Langmuir Circulations Transfer Kinetic Energy from Submesoscales and Larger Scales to Dissipative Scales

Abstract Surface gravity wave effects on currents (WEC) cause the emergence of Langmuir cells (LCs) in a suite of high horizontal resolution (Δx = 30 m), realistic oceanic simulations in the open ocean of central California. During large wave events, LCs develop widely but inhomogeneously, with larger vertical velocities in a deeper mixed layer. They interact with extant submesoscale currents. A 550-m horizontal spatial filter separates the signals of LCs and of submesoscale and larger-scale currents. The LCs have a strong velocity variance with small density gradient variance, while submesoscale currents are large in both. Using coarse graining, we show that WEC induces a forward cascade of kinetic energy in the upper ocean up to at least a 5-km scale. This is due to strong positive vertical Reynolds stress (in both the Eulerian and the Stokes drift energy production terms) at all resolved scales in the WEC solutions, associated with large vertical velocities. The spatial filter elucidates the role of LCs in generating the shear production on the vertical scale of Stokes drift (10 m), while submesoscale currents affect both the horizontal and vertical energy fluxes throughout the mixed layer (50–80 m). There is a slightly weaker forward cascade associated with nonhydrostatic LCs (by 13% in average) than in the hydrostatic case, but overall the simulation differences are small. A vertical mixing scheme K-profile parameterization (KPP) partially augmented by Langmuir turbulence yields wider LCs, which can lead to lower surface velocity gradients compared to solutions using the standard KPP scheme.

Acidity and metal complexation of edge surface of birnessite-type MnO2: Insight from first principles simulations.

Birnessite-type MnO2 plays key roles in scavenging trace elements in numerous natural environments and has also been regarded as a promising energy storage material. The interfacial properties of birnessite are highly pH-dependent due to the presence of various amphoteric groups on its edges, and, therefore, the acidity constants (pKa) of these groups are vital to the understanding of its electrochemical and environmental performances. However, an accurate acidity dataset for birnessite is absent yet. In this study, we employed first-principles molecular dynamics simulations and the vertical energy gap method to calculate the pKas of groups on the birnessite (010) edge. The interfacial hydration structure was characterized with a focus on the hydrogen bonding network. The obtained pKas suggest that MnOH2 is active while Mn2OH remains inert in a common pH range. Based on these results, the incorporation of transition metals on the edge surface was investigated by taking Ni2+ and Zn2+ as the model cations. The energy changes associated with the incorporation process of Ni2+ from the outer-sphere state indicate that incorporation on the edge surface is more feasible than that on the basal surface presumed in previous studies. Overall, the results obtained provide an atomic-scale insight into the acid-base chemistry of birnessite and form a physical basis for understanding the interfacial processes of birnessite.

Urban vertical farming with a large wind power share and optimised electricity costs

Producing food in an environmentally sustainable way for the growing human population is a challenge to the global food system. Vertical farm (VF) as a part of the solution portfolio is attracting interest since it uses less water, pesticides, and land which are scarce in many parts of the globe. Despite these positive factors, the energy demand for vertical farms is high, and farms often remain separate and excluded from cities where most of the population lives. City-level energy system solutions exist to empower energy efficiency and increase the share of variable renewable energy sources, but their potential has not yet been estimated for an urban energy system that includes large vertical farms. Accordingly, in this study, we simulate an urban energy system that practices vertical farming with large-scale variable renewable energies and flexibility measures. For the first part of the study, we modelled a vertical farm's energy system with demand response control to maximize electricity cost savings. To evaluate the potential of demand response, the analysis is carried out for different crops (lettuce, wheat, and soybean), and different electricity price profiles. The result of demand response control can be a reduction of 5% to 30% in electricity consumption costs. Further, sensitivity analyses highlight the effect of electricity price variations and photoperiod on demand response outcomes. In the second part, the operation of an urban energy system (Helsinki, Finland) with vertical farms was analysed through two different scenarios. These scenarios represent the emission-free Helsinki energy system in 2050 with large-scale wind power implementation. As VFs can use electricity outside the peak demand hours, the inclusion of VF with the right energy system configuration can improve the power consumption within the system by up to 19%. Further, we show that connection to the exogenous power market is important to support vertical farming in the future energy systems. In this study, key points in the integration of VF in urban energy systems are highlighted, including the role of exogenous power markets, the potential for increasing local energy consumption with large wind power, and the importance of crop selection in reducing VF's energy costs through demand response. In a city-level solution with a high wind power share, we thus recommend including a vertical farm side by strong sectoral coupling as part of the future design to maximise local consumption.

Numerical study of shell and tube latent thermal energy storage partially filled with metal foam and corrugated internal tube with external heat losses

In the present work, a vertical shell and tube Latent Heat Thermal Energy Storage System is analyzed. The cylinder is filled with phase change material and parts of metal foam. The inner face of the cylinder is corrugated, and it is assumed a constant temperature over the melting temperature of the paraffin wax to simulate the heat transfer. The external surface loses heat to the outside and the top and bottom surfaces are adiabatic. Paraffin wax is used as phase change material that melts over a range of temperatures and has a high latent heat of fusion. The thermal conductivity of the phase change material is low and due to this, it is enhanced with metal foam. In this numerical simulation, it is used the aluminum foam. Enthalpy-porosity theory is used to simulate the phase transition process, and the Local Thermal Equilibrium and Darcy-Forchheimer models are used to examine heat transport between the paraffin and the metal foam. Using the commercial code Ansys-Fluent, the governing equations’ solutions are calculated. In the paper, it is considered different conductivity variations on the external wall and the distinct filling ratio of metal foam. The melting time, enthalpy stored, and energy loss from the numerical simulations of the LHTESS charging phase are provided as a function of time and evaluated.

Analysis of explosive energy distribution at Pit 7 West PT. Makmur Mandiri Utama Binungan Suaran - Berau, East Kalimantan Province

Blasting geometry and blasting material filling are closely related to the rock mass characteristics and the geological conditions to obtain ideal fragmentation. Blastability Index analysis, including Description of Rock Mass, Combined Plane Spacing, Combined Plane Orientation, Specific Gravity Influencey, and Hardness, are the alternative geometry experiment conducted to overcome the problem of rock fragmentation so that the speed of excavation equipment can increase according to the productivity of Komatsu PC2000 plan at PT. BUMA Jobsite BINSUA. Furthermore, the actual rock values obtained from blasting location and alternative geometry recommendations using R.L.Ash theory combined with Vertical Energy Distribution theory. In the C2 layer with a rock factor value of 5.95, the recommended load is 7.2 m, space is 8.3 m, and the VED explosive power is 48%. In layer D2 the rock factor value is 6.89 with a load of 7.5 m, space of 8.3 m, and 55% VED explosive charge. While in the DU layer, the rock factor value is 6.39 with a load of 7.3 m, 8.4 m space, and 51% VED filling of explosives. Prediction of blasting fragmentation analysis using Kuz-ram theory obtained fragmentation > 100 cm, namely 14.99% for the C2 layer, 14.84% for the D2 layer, and 14.82% for the DU layer.

Vibration energy harvesting from tunnel invert-filling using rubberized concrete.

With the increasing operation mileage of urban rail transit, to ensure its operation safety, it is necessary to carry out health monitoring on the rail, tunnel, and other structures. How to capture the vibration energy generated by train operation and use it to monitor the power supply of sensors has become a research hotspot in recent years. In this paper, a new type of spherical energy harvester is designed for rubberized concrete tunnel invert-filling. Based on the calculation model of rubberized concrete tunnel invert-filling under train load, the vertical displacement, stress, voltage, and total electric energy are analyzed. The main conclusions are as follows: (1) The spherical energy harvester is embedded in the rubberized concrete tunnel invert-filling in the form of an array, and the optimal position is 5mm below the sleeper. (2) Ten energy harvesters are set up in the scope of a 6-m-long rubberized concrete tunnel invert-filling. The electric energy of the millijoule level can be generated when an A-type train of 8-vehicle formation passes by. If the departure interval of 5min/trip is calculated, the total electric energy harvesting in 1h is 122.4mJ. (3) Rubberized concrete tunnel invert-filling is more conducive to energy harvesting than ordinary concrete tunnel invert-filling. When the content of rubber is 10%, the total electric energy harvesting by the energy harvester array inside the tunnel invert-filling is 5% higher than that of the ordinary concrete, and the mechanical performance indexes such as stress are within the safe range. The research results of this paper have reference value for further exploration of electric energy harvesting in the running environment of rail transit trains.

2D Oxides Realized via Confinement Heteroepitaxy

AbstractNovel confinement techniques facilitate the formation of non‐layered 2D materials. Here it is demonstrated that the formation and properties of 2D oxides (GaOx, InOx, SnOx) at the epitaxial graphene (EG)/silicon carbide (SiC) interface is dependent on the EG buffer layer properties prior to element intercalation. Using 2D Ga, it is demonstrated that defects in the EG buffer layer lead to Ga transforming to GaOx with non‐periodic oxygen in a crystalline Ga matrix via air oxidation at room temperature. However, crystalline monolayer GaO2 and bilayer Ga2O3 with ferroelectric wurtzite structure(FE‐WZ') can then be formed via subsequent high‐temperature O2 annealing. Furthermore, the graphene/X/SiC (X = 2D Ga or Ga2O3) junction is tunable from Ohmic to a Schottky or tunnel barrier depending on the interface species. Finally, using vertical transport measurements and electron energy loss spectroscopy analysis, the bandgap of 2D gallium oxide is identified as 6.6 ± 0.6 eV, significantly larger than that of bulk β‐Ga2O3 (≈4.8 eV), suggesting strong quantum confinement effects at the 2D limit. The study presented here is foundational for development of atomic‐scale, vertical 2D/3D heterostructure for applications requiring short transit times, such as GHz and THz devices.

Analytical solutions of the energy harvesting potential from vehicle vertical vibration based on statistical energy conservation

Two kinds of approaches have been proposed to harvest the vibrational energy from a running vehicle, namely using a regenerative damper to replace a traditional hydraulic suspension damper, or adding one or more dynamic vibration absorbers (DVAs). Extensive studies have been conducted by simulation or experiment on the first approach, whereas the studies on the second approach are very limited and even the energy harvesting potential is not clear. This paper tries to present an analytical solution, to uniformly reveal the energy harvesting potential from vehicle vertical vibration by both approaches, with a focus on approaches with DVAs. A generic quarter car model is proposed to represent various vibration energy harvesting configurations. With a newly enunciated statistical energy conservation property for linear vibration systems, the analytical solution of the energy harvesting potential is derived for the proposed model subjected to random excitation. It is illustrated from these analytical expressions that the total vehicle vertical vibration energy is not directly related to DVA configurations, and the vibration energy dissipated in the tire can be transferred to the absorbers. Literature results and newly implemented statistical analyses are presented to validate and demonstrate the derived solutions. Sensitivity analysis is then performed to reveal the effect of various vehicle parameters on the energy harvesting potential.

Numerical investigation on melting and thermal performances of a phase change material in partitioned cavities with fins for thermal energy storage

The practical application of solid-liquid phase transition latent thermal energy storage devices is restricted by the low value of thermal conductivity in phase change materials (PCMs). To alleviate this problem, a proposal for a newly developed thermal energy storage unit with metal multiple partitions and flat fins coupled is presented in this paper. The design was constructed by dividing the typical vertical rectangular thermal energy storage unit into several partitions (1, 2, 4, and 8), including 4-fins and 8-fins in different partitions. A 2D transient solid-liquid phase change numerical model was firstly validated and then the effect of different configurations was numerically determined to obtain the thermal energy storage characteristics, velocity field, solid-liquid interface, temperature distributions, and thermal transfer performances. The results show that the optimized metal partitioned cavities lower the PCM's melting time with the maximum melting time reduction occurring at a value of 76.8 % compared to the common wooden partition. Because of increased thermal networks or enhanced local natural convection, increasing the cavity partitioning and fins shortens the melting time of the PCM. The 8-partitions cavity coupled with 8-fins generates the shortest melting time. Increasing the quantity of cavity partitioning and fins also leads to a reduction in the time needed to attain the largest amount of stored energy and an increase in the Nusselt number and power.

Effect of shell shape on the charging and discharging performance of a vertical latent heat thermal energy storage unit: An experimental study

In this paper, the effect of shell shape on vertical latent heat thermal energy storage (LHTES) unit is experimentally investigated to alleviate the heat transfer lagging region and enhance its charging and discharging performance. A cylindrical (CYL) and two conical (CON-I and CON-II) LHTES units are designed and fabricated, and they have the same heat transfer area and internal volume. Paraffin with a narrow range of phase change temperature and high enthalpy was selected as phase change material (PCM), and water is used as heat transfer fluid (HTF). The thermal behaviors of CYL, CON-I and CON-II such as evaluation of melting and solidification fronts, temperature response characteristics, heat transfer characteristics and energy and exergy conversion are comparatively studied. A correlation is developed to predict the entire melting and solidification time of different LHTES units under different HTF flow rates and temperatures. The results demonstrate that CON-I and CON-II can provide a better temperature field uniformity and enhance the heat transfer rate between HTF and PCM. When compared with CYL, the entire melting/solidification time is reduced by 16.95 %/8.07 % and 29.94 %/23.22 % for CON-I and CON-II, and the time-averaged heat transfer rate is increased by 20.69 %/23.61 % and 35.87 %/41.24 % for CON-I and CON-II during the melting/solidification processes. In addition, the developed correlation is able to well predict the entire melting and solidification time of PCM in the LHTES unit with a relative error of ±5 %.

Cloud Radiative Effects on MJO Development in DYNAMO

Abstract Observed Madden–Julian oscillation (MJO) events are examined with the aid of regional model simulations to understand the role of cloud radiative effects in the MJO development. The importance of this role is demonstrated by the absence of the MJO in the model simulations that contain no cloud radiative effects. Comparisons of model simulations with and without the cloud radiative effects and observation help identify the major processes arising from those effects. Those processes develop essentially from heating in the upper troposphere due to shortwave absorption within anvil clouds in the upper troposphere and the convergence of longwave radiation in the middle to upper troposphere, with a peak at 300 hPa, during deep convection. First, that heating adds extra buoyancy and accelerates the rising motion in the upper troposphere in deep convection. The vertical acceleration in the upper troposphere creates a vacuum effect and demands for more deep convection to develop. Second, in response to that demand and required by mass balance arises the large-scale horizontal and vertical mass, moisture, and energy convergence. It strengthens deep convection and, with the feedback from continuing cloud radiative effect, creates conditions that can perpetuate deep convection and MJO development. That perpetuation does not occur however because those processes arising from the cloud radiative heating in the upper troposphere stabilize the troposphere until it supports no further deep convection. Weakening deep convection reduces cloud radiative effects. The subsequent reduction of the vacuum effect in the upper troposphere diminishes deep convection completing an MJO cycle. These results advance our understanding of the development of the MJO in the radiative–convective system over warm waters in the tropics. They show that while the embryo of intraseasonal oscillation may exist in the system its growth/development is largely dependent on cloud radiative effects and feedbacks.

Integrate a high precision scan magnet power supply in NSRRC

This work describes the integration of a high precision power supply in a scan magnet in National Synchrotron Radiation Research Center (NSRRC). Horizontal and vertical energy transmission to the scan magnet are independent. The high precision and sinewave are utilised to produce a smooth circle field. This power supply has an air cooling system and a more protective function to keep the machine and magnet from being damaged. During the scan magnet application, the maximum current is 12.5 A, and the inductor is 30 mH at 20 Hz sine wave. Accordingly, Kecpo BOP 72-14 model with a maximum current of 14 A and maximum output voltage of 72 V is chosen. Finally, an integrated high-precision scan magnet power supply is created in the laboratory. Experimental result shows the output current ripple and bandwidth, with the output current being 14 A and the maximum ripple being 0.45 A. This combination is simple because no resistor is in parallel with the magnet coils. Lastly, this work demonstrates the magnetic field, output current ripple, and frequency variation with output current to prove that this power supply meets the requirements.

Influences of Mesoscale Ocean Eddies on Flow Vertical Structure in a Resolution‐Based Model Hierarchy

AbstractThe understanding and representation of energetic transfers associated with ocean mesoscale eddies is fundamental to the development of parameterizations for climate models. We investigate the influence of eddies on flow vertical structure as a function of underlying dynamical regime and grid resolution. We employ the GFDL‐MOM6 in an idealized configuration and systematically consider four horizontal resolutions: 1/4°, 1/8°, 1/16°, and 1/32°. We analyze the distributions of potential and kinetic energy, decomposed into barotropic and baroclinic, and eddy and mean parts. As resolution increases and baroclinically unstable modes are better captured, kinetic energy increases and potential energy decreases. The dominant trend in vertical structure is an increasing fraction of kinetic energy going into the barotropic mode, particularly its eddy component, as eddies are increasingly resolved. We attribute the increased baroclinicity at low resolutions to inaccurate representation of vertical energy fluxes, leading to suppressed barotropization and energy trapping in high vertical modes. We also explore how the underlying dynamical regime influences energetic pathways. In cases where large‐scale flow is dominantly barotropic, resolving the deformation radius is less crucial to accurately capturing the flow's vertical structure. We find the barotropic kinetic energy fraction to be a useful metric in assessing vertical structure. In the highest‐resolution case, the barotropic kinetic energy fraction correlates with the scale separation between the deformation scale and the energy‐containing scale, that is, the extent of the eddy‐driven inverse cascade. This work suggests that mesoscale eddy parameterizations should incorporate the energetic effects of eddies on vertical structure in a scale‐aware, physically informed manner.

Impacts of Instrumented Bottom Frame on Flow and Turbulence Measurements

Abstract A series of laboratory experiments are carried out to demonstrate the impacts of instrumented bottom frame legs on flow and turbulence. The magnitudes of vertical velocity, turbulent kinetic energy, dissipation, and shear stress induced by the frame legs depend on several factors, including the diameter and number of the frame legs, distances between the legs and the observational location, and the magnitude of the incoming flow and its direction with respect to the layout of the frame. In situ observations were carried out near the mouth of the Yellow River using two acoustic Doppler velocimeters mounted on a bottom frame. The estimated vertical velocity and turbulent kinetic energy dissipation rate show a significant asymmetry with flood and ebb tidal flows. This asymmetry can be partly explained by the influences of the bottom frame legs. Finally, the design and deployment principles of bottom frames are discussed for the purpose of reducing the impacts of the frame legs. Significance Statement Instrumented bottom frames are widely used for observations in the oceanic bottom boundary layer and above. However, the impacts of frame legs on the observed flow and turbulence have rarely been investigated. A series of laboratory experiments demonstrate that frame legs can induce vertical flow and enhanced turbulence, and the magnitudes of these influences vary with the size and layout of the frame legs and the magnitude and direction of the background flow. The results of the laboratory experiments can partially explain an “asymmetry” behavior of the vertical flow and turbulent kinetic energy with the flood and ebb tidal flows, derived from in situ observations near the mouth of the Yellow River.

Amino acid isotopes in functional assemblages of Collembola reveal the influence of vertical resource heterogeneity and root energy supply on trophic interactions in soil food webs

The vertical heterogeneity of trophic interactions in soil food webs in temperate forest systems and its response to deprivation of root energy supply are poorly understood. In the present study, community-level trophic niches of Collembola functional groups (epedaphic, hemiedaphic and euedaphic) were analyzed using compound specific isotope analysis (CSIA) of carbon (C) and nitrogen (N) in amino acids (AAs) in a root-trenching experiment. The δ15N values of phenylalanine, serving as proxy for N resources, were higher in euedaphic Collembola than in ep-/hemiedaphic Collembola, suggesting that euedaphic Collembola mainly utilized N from processed organic substrate in deeper soil, while leaf litter was the dominant N source for ep-/hemiedaphic Collembola. The trophic position calculated from CSIA (TPCSIA) of euedaphic Collembola was higher than that of epedaphic Collembola in most of the studied forest sites, reflecting a higher number of trophic transfers in the soil than in the litter layer. For the first time, we found evidence that the deprivation of root energy supply can decrease the TPCSIA of soil omnivores, suggesting that root-derived C may increase the number of trophic transfers and food chain length in soil food webs. However, effects varied among functional groups of Collembola in different forest stands, indicating that the association between root energy supply and trophic interactions is only partially in line with the ‘productivity hypothesis’ and strongly mediated by vertical resource heterogeneity, regional conditions and feeding strategies of consumers. Finally, our results are in line with recent studies, suggesting that saprotrophic microorganisms, especially saprotrophic fungi, are the predominant resources for Collembola, whereas the contribution of mycorrhizal fungi and plants is subordinate. Overall, by using CSIA of AAs our study provides novel information on trophic niches of microarthropods in forest soils, extending our understanding of the influences of vertical resource heterogeneity and root energy supply on trophic interactions in soil food webs.

High‐Resolution Aircraft Observations of Turbulence and Waves in the Free Atmosphere and Comparison With Global Model Predictions

AbstractHigh‐resolution flight data obtained from in situ measurements in the free atmosphere aboard the High Altitude and Long Range Research Aircraft (HALO) are used to determine eddy dissipation rates along extended flights during the recent Southern Hemisphere Transport, Dynamics, and Chemistry aircraft campaign (SOUTHTRAC) in the 2019 austral winter. These data are analyzed and correlated with quantities characterizing the ambient airflow and the magnitudes of vertical energy propagation through internal gravity waves. The observed turbulence events are strongly correlated with elevated shear values, and overturning gravity waves do not appear to play a role. A highlight of the analysis is the validation of a recently implemented Clear Air Turbulence (CAT) forecast index in the European Centre for Medium‐Range Weather Forecast integrated forecast system. Here we find a slightly better correlation of the CAT prediction with the HALO research aircraft observations compared to those of commercial aircraft. The observed turbulence during SOUTHTRAC was never stronger than moderate, as EDR values remained below 0.3 m2/3 s−1. In general, light and light‐to‐moderate turbulence events were extremely rare, occurring in only about 5% of the flight time, and stronger events in less than 0.2%. These results are also reflected in the local atmospheric conditions, which were dominated by a thermally very stable airflow with low vertical shear and large Richardson numbers.

Development of Multilevel Organic Phototransistor Memory using Conjugated/Insulating Polymer Blends with a Vertical Phase Separation

AbstractIn this work, a series of methacrylate‐based polymers bearing benzene (poly(benzyl methacrylate)), naphthalene (poly(2‐naphthyl methacrylate)), anthracene (poly(9‐anthracenyl methyl methacrylate), PAMA), and pyrene (poly(1‐pyrenemethyl methacrylate)) are blended with conjugated polymer of poly(3‐hexylthiophene) (P3HT) to perform vertical phase separation during spin‐coating. The bilayer structure of the conjugated/insulating polymer blend is driven by their mismatch in surface energy, and the blend films are applied in the phototransistor memory device with the bottom layer of methacrylate‐based polymer as a photoactive electret and the top layer of P3HT as a semiconducting channel. It is found that the vertical phase separation morphology, conjugation, and energy levels of the pendant arene groups in the methacrylate‐based polymers are highly related to the photoresponse, memory retention/endurance of the phototransistor memory. Therefore, the device comprising the polymer blend of P3HT and PAMA successfully produces a high current contrast of 105 to 254 nm light and 104 to 450 nm light over 104 s. This study provides a facile approach to the fabrication of high‐performance phototransistor memory devices.