scholarly journals Stormtime Energetics: Energy Transport Across the Magnetopause in a Global MHD Simulation

2021 ◽  
Vol 8 ◽  
Author(s):  
Austin Brenner ◽  
Tuija I. Pulkkinen ◽  
Qusai Al Shidi ◽  
Gabor Toth
Keyword(s):  
Energy Transfer ◽  
Energy Flux ◽  
Energy Transport ◽  
Regional Distribution ◽  
Energy Coupling ◽  
Energy Output ◽  
Closed Field ◽  
Net Energy ◽  
Modeling Framework ◽  
Poynting Flux

Coupling between the solar wind and magnetosphere can be expressed in terms of energy transfer through the separating boundary known as the magnetopause. Geospace simulation is performed using the Space Weather Modeling Framework (SWMF) of a multi-ICME impact event on February 18–20, 2014 in order to study the energy transfer through the magnetopause during storm conditions. The magnetopause boundary is identified using a modified plasma β and fully closed field line criteria to a downstream distance of −20Re. Observations from Geotail, Themis, and Cluster are used as well as the Shue 1998 model to verify the simulation field data results and magnetopause boundary location. Once the boundary is identified, energy transfer is calculated in terms of total energy flux K, Poynting flux S, and hydrodynamic flux H. Surface motion effects are considered and the regional distribution of energy transfer on the magnetopause surface is explored in terms of dayside X>0, flank X<0, and tail cross section X=Xmin regions. It is found that total integrated energy flux over the boundary is nearly balanced between injection and escape, and flank contributions dominate the Poynting flux injection. Poynting flux dominates net energy input, while hydrodynamic flux dominates energy output. Surface fluctuations contribute significantly to net energy transfer and comparison with the Shue model reveals varying levels of cylindrical asymmetry in the magnetopause flank throughout the event. Finally existing energy coupling proxies such as the Akasofu ϵ parameter and Newell coupling function are compared with the energy transfer results.

Investigating magnetopause dynamics using global magnetosphere simulation 

2021 ◽  
Author(s):  
Austin Brenner ◽  
Tuija Pulkkinen
Keyword(s):  
Energy Transfer ◽  
Space Weather ◽  
Flow Line ◽  
Storm Event ◽  
Closed Volume ◽  
Modeling Framework ◽  
Area Element ◽  
Poynting Flux ◽  
Total Energy Flux ◽  
Tracing Techniques

&lt;p&gt;Detailed 3D magnetopause surface is identified using field line and flow line tracing techniques on Space Weather Modeling Framework (SWMF) global magnetosphere simulation results. A total energy flux vector dominated by poynting flux is dotted with area element surface normals and integrated to determine energy transfer into the closed volume. Magnetopause characteristics, power and energy terms are compared with space weather indices such as Disturbance Storm-Time (Dst), Auroral Electrojet (AE), Cross Polar Cap Potential (CPCP) and emperical models such as Shue et al (1997) and Shue et al (1998) to investigate magnetopause dynamics.&amp;#160;The storm event of Feb 18, 2014 &amp;#160;is simulated with SWMF and analyzed. This event starts in the middle of a multi-CME impact, during a delay between the first and second CME's. While some preconditioning may have occured, it provides an excellent case for observing magnetopause variations. Results show close agreement with empirical models of integrated energy transfer through magnetopause surface. Energy accumulation inside magnetopause volume cuttoff at x=-20Re shows similar behavior to Dst.&lt;/p&gt;

scholarly journals Evaluation of Regional Surface Energy Budget Over Ocean Derived From Satellites

2021 ◽  
Vol 8 ◽  
Author(s):  
Seiji Kato ◽  
Fred G. Rose ◽  
Fu-Lung Chang ◽  
David Painemal ◽  
William L. Smith
Keyword(s):  
Energy Balance ◽  
Surface Energy ◽  
Energy Flux ◽  
Energy Transport ◽  
Energy Balance Equation ◽  
Surface Energy Budget ◽  
Global Ocean ◽  
Net Energy ◽  
Tropical Ocean ◽  
Surface Energy Flux

The energy balance equation of an atmospheric column indicates that two approaches are possible to compute regional net surface energy flux. The first approach is to use the sum of surface energy flux components Fnet,c and the second approach is to use net top-of-atmosphere (TOA) irradiance and horizontal energy transport by the atmosphere Fnet,t. When regional net energy flux is averaged over the global ocean, Fnet,c and Fnet,t are, respectively, 16 and 2 Wm–2, both larger than the ocean heating rate derived from ocean temperature measurements. The difference is larger than the estimated uncertainty of Fnet,t of 11 Wm–2. Larger regional differences between Fnet,c and Fnet,t exist over tropical ocean. The seasonal variability of energy flux components averaged between 45°N and 45°S ocean reveals that the surface provides net energy to the atmosphere from May to July. These two examples demonstrates that the energy balance can be used to assess the quality of energy flux data products.

scholarly journals Structure of cyanobacterial phycobilisome core revealed by structural modeling and chemical cross-linking

2021 ◽  
Vol 7 (2) ◽  
pp. eaba5743
Author(s):  
Haijun Liu ◽  
Mengru M. Zhang ◽  
Daniel A. Weisz ◽  
Ming Cheng ◽  
Himadri B. Pakrasi ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Excitation Energy Transfer ◽  
Energy Coupling ◽  
Regulatory Elements ◽  
Photochemical Activity ◽  
Structural Basis ◽  
Bottom Surface ◽  
Cross Linking ◽  
Orange Carotenoid Protein ◽  
Chemical Cross Linking

In cyanobacteria and red algae, the structural basis dictating efficient excitation energy transfer from the phycobilisome (PBS) antenna complex to the reaction centers remains unclear. The PBS has several peripheral rods and a central core that binds to the thylakoid membrane, allowing energy coupling with photosystem II (PSII) and PSI. Here, we have combined chemical cross-linking mass spectrometry with homology modeling to propose a tricylindrical cyanobacterial PBS core structure. Our model reveals a side-view crossover configuration of the two basal cylinders, consolidating the essential roles of the anchoring domains composed of the ApcE PB loop and ApcD, which facilitate the energy transfer to PSII and PSI, respectively. The uneven bottom surface of the PBS core contrasts with the flat reducing side of PSII. The extra space between two basal cylinders and PSII provides increased accessibility for regulatory elements, e.g., orange carotenoid protein, which are required for modulating photochemical activity.

scholarly journals Energy budget and carbon footprint in a wheat and maize system under ridge furrow strategy in dry semi humid areas

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Changjiang Li ◽  
Shuo Li
Keyword(s):  
Carbon Footprint ◽  
Energy Budget ◽  
Agricultural Development ◽  
Energy Use ◽  
Cropping System ◽  
Energy Output ◽  
Net Energy ◽  
Energy Productivity ◽  
Carbon Efficiency ◽  
Net Returns

AbstractThe well-irrigated planting strategy (WI) consumes a large amount of energy and exacerbates greenhouse gas emissions, endangering the sustainable agricultural production. This 2-year work aims to estimate the economic benefit, energy budget and carbon footprint of a wheat–maize double cropping system under conventional rain-fed flat planting (irrigation once a year, control), ridge–furrows with plastic film mulching on the ridge (irrigation once a year, RP), and the WI in dry semi-humid areas of China. Significantly higher wheat and maize yields and net returns were achieved under RP than those under the control, while a visible reduction was found for wheat yields when compared with the WI. The ratio of benefit: cost under RP was also higher by 10.5% than that under the control in the first rotation cycle, but did not differ with those under WI. The net energy output and carbon output followed the same trends with net returns, but the RP had the largest energy use efficiency, energy productivity carbon efficiency and carbon sustainability among treatments. Therefore, the RP was an effective substitution for well–irrigated planting strategy for achieving sustained agricultural development in dry semi-humid areas.

Different energetics of global monsoon over land and ocean

2021 ◽  
Author(s):  
Arindam Chakraborty ◽  
Chetankumar Jalihal ◽  
Jayaraman Srinivasan
Keyword(s):  
Surface Energy ◽  
Energy Flux ◽  
Global Climate ◽  
Lower Troposphere ◽  
Summer Precipitation ◽  
Reanalysis Data ◽  
Vertical Transport ◽  
Net Energy ◽  
Global Monsoon ◽  
Surface Energy Flux

&lt;p&gt;Monsoons were traditionally considered to be land-based systems. Recent definitions of monsoons based on either the seasonal reversal of winds or the local summer precipitation accounting for more than 50% of the annual precipitation suggests that monsoon domains extend over oceanic regions as well. The concept of global monsoon combines all the monsoon domains into a single entity. Modern observations show that the variations in precipitation are nearly coherent across all the individual monsoon domains on decadal timescales. Using a transient simulation of the global climate over the last 22,000 years as well as reanalysis data of the modern climate, we have shown that tropical precipitation has different characteristics over land and ocean grids. This is due to the differences in the energetics of monsoon over land and ocean grids. With a lower thermal heat capacity, the net surface energy flux over land is negligible, whereas it is quite large over the ocean. In fact, the orbital scale variability of net energy flux into the atmosphere over the ocean is controlled by the surface energy flux. Another major difference between land and ocean grids of the global monsoon is in the vertical profile of the vertical pressure velocity. It is bottom-heavy over land and top-heavy over the ocean. This results in smaller vertical transport of moist static energy (which has a minimum in the lower troposphere) over land, and a larger vertical transport over the ocean. These differences between the land and ocean, suggest that the land and ocean grids should not be combined as is traditionally done. Global monsoon-land and global monsoon-ocean should be studied separately.&lt;/p&gt;

scholarly journals A statistical comparison of SuperDARN spectral width boundaries and DMSP particle precipitation boundaries in the morning sector ionosphere

2005 ◽  
Vol 23 (3) ◽  
pp. 733-743 ◽  
Author(s):  
G. Chisham ◽  
M. P. Freeman ◽  
T. Sotirelis ◽  
R. A. Greenwald ◽  
M. Lester ◽  
...  
Keyword(s):  
Energy Flux ◽  
Spectral Width ◽  
Incident Electron Energy ◽  
Small Scale ◽  
Closed Field ◽  
Particle Precipitation ◽  
Ionospheric Conductivity ◽  
Morning Sector ◽  
Latitudinal Difference ◽  
Good Proxy

Abstract. Determining reliable proxies for the ionospheric signature of the open-closed field line boundary (OCB) is crucial for making accurate ionospheric measurements of many magnetospheric processes (e.g. magnetic reconnection). This study compares the latitudes of Spectral Width Boundaries (SWBs), identified in the morning sector ionosphere using the Super Dual Auroral Radar Network (SuperDARN), with Particle Precipitation Boundaries (PPBs) determined using the low-altitude Defense Meteorological Satellite Program (DMSP) spacecraft, in order to determine whether the SWB represents a good proxy for the ionospheric projection of the OCB. The latitudes of SWBs and PPBs were identified using automated algorithms applied to 5 years (1997-2001) of data measured in the 00:00-12:00 Magnetic Local Time (MLT) range. A latitudinal difference was measured between each PPB and the nearest SWB within a ±10min Universal Time (UT) window and within a ±1h MLT window. The results show that the SWB represents a good proxy for the OCB close to midnight (~00:00-02:00 MLT) and noon (~08:00-12:00 MLT), but is located some distance (~2°-4°) equatorward of the OCB across much of the morning sector ionosphere (~02:00-08:00 MLT). On the basis of this and other studies we deduce that the SWB is correlated with the poleward boundary of auroral emissions in the Lyman-Birge-Hopfield ``Long" (LBHL) UV emission range and hence, that spectral width is inversely correlated with the energy flux of precipitating electrons. We further conclude that the combination of two factors may explain the spatial distribution of spectral width values in the polar ionospheres. The small-scale structure of the convection electric field leads to an enhancement in spectral width in regions close to the OCB, whereas increases in ionospheric conductivity (relating to the level of incident electron energy flux) lead to a reduction in spectral width in regions just equatorward of the OCB.

scholarly journals Efficient Interlayer Exciton Transport in Two-Dimensional Metal-Halide Perovskites.

2020 ◽  
Author(s):  
Alvaro J Magdaleno ◽  
Michael Seitz ◽  
Michel Frising ◽  
Ana Herranz de la Cruz ◽  
Antonio I. Fernández-Domínguez ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Charge Carrier ◽  
Carrier Transport ◽  
Energy Transport ◽  
Diffusion Length ◽  
Charge Carrier Transport ◽  
Two Dimensional ◽  
Exciton Transport ◽  
Halide Perovskites ◽  
Excitonic Energy

We present transient microscopy measurements of interlayer energy transport in (PEA)<sub>2</sub>PbI<sub>4</sub> perovskite. We find efficient interlayer exciton transport (0.06 cm<sup>2</sup>/s), which translates into a diffusion length that exceeds 100 nm and a sub-ps timescale for energy transfer. While still slower than in-plane exciton transport (0.2 cm<sup>2</sup>/s), our results show that excitonic energy transport is considerably less anisotropic than charge-carrier transport for 2D perovskites.

scholarly journals The Impact of Climate Change on the Value of Growing Maize as a Biofuel

2020 ◽  
Vol 4 (1) ◽  
pp. 13-26
Author(s):  
Sally Olasogba ◽  
Les DUCKERS
Keyword(s):  
Climate Change ◽  
Carbon Footprint ◽  
Carbon Emissions ◽  
Energy Use ◽  
Farm Management ◽  
Energy Output ◽  
Net Energy ◽  
Primary Concern ◽  
Impact Of Climate Change ◽  
The Impact

Abstract: Aim: According to COP23, Climate Change threatens the stability of the planet’s ecosystems, with a tipping point believed to be at only +2°C.  With the burning of fossil fuels, held responsible for the release of much of the greenhouse gases, a sensible world- wide strategy is to replace fossil fuel energy sources with renewable ones. The renewable resources such as wind, hydro, geothermal, wave and tidal energies are found in particular geographical locations whereas almost every country is potentially able to exploit PV and biomass. This paper examines the role that changing climate could have on the growing and processing of biomass. The primary concern is that future climates could adversely affect the yield of crops, and hence the potential contribution of biomass to the strategy to combat climate change. Maize, a C4 crop, was selected for the study because it can be processed into biogas or other biofuels. Four different Nigerian agricultural zones growing maize were chosen for the study. Long-term weather data was available for the four sites and this permitted the modelling of future climates. Design / Research methods: The results of this study come from modelling future climates and applying this to crop models. This unique work, which has integrated climate change and crop modelling to forecast yield and carbon emissions, reveals how maize responds to the predicted increased temperature, change in rainfall, and the variation in weather patterns. In order to fully assess a biomass crop, the full energy cycle and carbon emissions were estimated based on energy and materials inputs involved in farm management: fertilizer application, and tillage type. For maize to support the replacement strategy mentioned above it is essential that the ratio of energy output to energy input exceeds 1, but of course it should be as large as possible. Conclusions / findings: Results demonstrate that the influence of climate change is important and in many scenarios, acts to reduce yield, but that the negative effects can be partially mitigated by careful selection of farm management practices. Yield and carbon footprint is particularly sensitive to the application rate of fertilizer across all locations whilst climate change is the causal driver for the increase in net energy and carbon footprint at most locations. Nonetheless, in order to ensure a successful strategic move towards a low carbon future, and sustainable implementation of biofuel policies, this study provides valuable information for the Nigerian government and policy makers on potential AEZs to cultivate maize under climate change. Further research on the carbon footprint of alternative bioenergy feedstock to assess their environmental carbon footprint and net energy is strongly suggested. Originality / value of the article: This paper extends the review on the impact of climate change on maize production to include future impacts on net energy use and carbon footprint using a fully integrated assessment framework. Most studies focus only on current farm energy use and historical climate change impact on farm GHG emissions.   

scholarly journals Cooling Induced by Uphill Energy Transport in Plant Photosystems

2017 ◽  
Author(s):  
Koel Sen ◽  
Abhishek Bhattacharya ◽  
Santiswarup Singha ◽  
Maitrayee Dasgupta ◽  
Anjan Kr Dasgupta
Keyword(s):  
Energy Transport ◽  
Electron Flow ◽  
Surrounding Medium ◽  
Food Preservation ◽  
Energy Output ◽  
Cooling Pattern ◽  
Laser Systems ◽  
Wavelength Emission ◽  
Cooling Effects ◽  
First Time

AbstractThe uphill energy transfer in photosystems implies input energy at higher wavelength leading to energy output at lower wavelength. Briefly, energy is uphill transported from photosystem I (PSI) to photosystem II (PSII), the latter having a lower wavelength emission. This uphill energy transport involves absorption of thermal energy from the surroundings. While such cooling effects have been reported in laser systems we report for the first time a white light driven cooling in thylakoid suspension. The cooling of the surrounding medium by appropriate illumination was illustrated using thermal measurements. Again cooling is inhibited by agents like 3-(3,4-Dichlorophenyl)-1,1-dimethylurea,that block the linear electron flow between the photocenters, implying a dependence of the cooling on interplay between such centers. Furthermore, it is possible to modulate the cooling pattern by addition of external agents like nanopaticles, some favoring further cooling (e.g., Ag nanoparticle) and some like Au or chlorophyll nanoparticles, showing insignificant or even reverse trends. Interestingly, the cooling is invariably associated with the 77K spectra of the thylakoid suspension. With reference to the dark control, an agent causing cooling always increases PSII to PSI ratio and vice versa i.e.,the uphill energy transport. Importantly, the cooling effect, apart from its import role in plant physiology can be exploited artificially for energy saving in post-harvest or food preservation.

scholarly journals Evaluating the Impacts of ACP Management on the Energy Performance of Hydrothermal Liquefaction via Nutrient Recovery

Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 729 ◽  
Author(s):  
Sarah Bauer ◽  
Fangwei Cheng ◽  
Lisa Colosi
Keyword(s):  
Life Cycle ◽  
Energy Performance ◽  
Hydrothermal Liquefaction ◽  
Liquid Fuels ◽  
Precipitation Process ◽  
Net Energy ◽  
Modeling Framework ◽  
Energy Return On Investment ◽  
Theoretical Yield ◽  
Struvite Precipitation

Hydrothermal liquefaction (HTL) is of interest in producing liquid fuels from organic waste, but the process also creates appreciable quantities of aqueous co-product (ACP) containing high concentrations of regulated wastewater pollutants (e.g., organic carbon, nitrogen (N), and phosphorus (P)). Previous literature has not emphasized characterization, management, or possible valorization of ACP wastewaters. This study aims to evaluate one possible approach to ACP management via recovery of valuable scarce materials. Equilibrium modeling was performed to estimate theoretical yields of struvite (MgNH4PO4·6H2O) from ACP samples arising from HTL processing of selected waste feedstocks. Experimental analyses were conducted to evaluate the accuracy of theoretical yield estimates. Adjusted yields were then incorporated into a life-cycle energy modeling framework to compute energy return on investment (EROI) for the struvite precipitation process as part of the overall HTL life-cycle. Observed struvite yields and residual P concentrations were consistent with theoretical modeling results; however, residual N concentrations were lower than model estimates because of the volatilization of ammonia gas. EROI calculations reveal that struvite recovery is a net-energy producing process, but that this benefit offers little to no improvement in EROI performance for the overall HTL life-cycle. In contrast, corresponding economic analysis suggests that struvite precipitation may be economically appealing.

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