High fidelity estimates of paratransit energy consumption from per-second GPS tracking data

Paratransit, in particular the minibus taxi, is the mainstay of public transport in sub-Saharan Africa. These vehicles are often second-hand, ageing, fuel inefficient, and expensive to operate - issues that electrification can ameliorate. However, modeling and planning large-scale transitions to electric paratransit require reliable estimates of vehicle energy consumption. This paper provides such estimates by applying a vehicle kinetic model to per-second GPS data gathered on minibus taxis. Data include 62 trips across three routes with different driving conditions near Stellenbosch, South Africa. We find a range of energy consumption from 0.29 to 0.51 kWh/km (mean = 0.39 kWh/km). Past estimates in literature relied on per-minute GPS data, which we show leads to inaccurate energy consumption estimates. We recommend new kWh/km values for modeling vehicle operations and grid impact, and discuss how future work can utilize our analysis to advance the transition to electric paratransit sub-Saharan Africa

Forecast of electric vehicle uptake across counties in England : Dataset from S-curve analysis

Regional data from the UK Government's Department for Transport has been analyzed to produce a forecasted dataset of the uptake of electric vehicles (EVs) within Counties of England to the first quarter of the year 2100 using an S-curve methodology. This data includes all vehicles, not just cars. The historic proportion of electric vehicles in the fleets of these regions is calculated using data from 2011 Q4 to 2021 Q1. This data is then analyzed using SCATE, the S-Curve Adoption Tool for EVs to forecast the future proportion of electric vehicles in these Counties. Two data tables are presented: the reformatted historic data and the data from the S-curve analysis. Data is also presented for the collective UK

Geospatial analysis to identify promising car parks for installing electric vehicle charge points : an Oxford case study

Historically in the UK, uptake of electric vehicles (EVs) has been dominated by those with off-street parking. In fact, a recent report by Deloitte found that nearly 90% of EV drivers currently charge privately. However, if we wish to meet the UK Government's targets of net zero by 2050 and no further sales of fully internal combustion engine vehicles after 2030, EV charging will need to be made accessible to those without driveways. Local Authorities and the companies they work with have a significant role to play in infrastructure planning to get ahead of the curve of accelerating EV uptake. This Visualising Transport Geography article investigates whether it is possible to identify locations for public EV chargers which may be more valuable to residents

OPEN : an open-source platform for developing smart local energy system applications

This paper presents OPEN, an open-source software platform for integrated modelling, control and simulation of smart local energy systems. Electric power systems are undergoing a fundamental transition towards a significant proportion of generation and flexibility being provided by distributed energy resources. The concept of ‘smart local energy systems’ brings together related strategies for localised management of distributed energy resources, including active distribution networks, microgrids, energy communities, multi-energy hubs, peer-to-peer trading platforms and virtual power plants. OPEN provides an extensible platform for developing and testing new smart local energy system management applications, helping to bridge the gap between academic research and industry translation. OPEN combines features for managing smart local energy systems which are not provided together by existing energy management tools, including multi-phase distribution network power flow, energy market modelling, nonlinear energy storage modelling and receding horizon optimisation. The platform is implemented in Python with an object-oriented structure, providing modularity and allowing it to be easily integrated with third-party packages. Case studies are presented, demonstrating how OPEN can be used for a range of smart local energy system applications due to its support of multiple model fidelities for simulation and control

Meteorological and Back Trajectory Modeling for the Rocky Mountain Atmospheric Nitrogen and Sulfur Study II

The Rocky Mountain Atmospheric Nitrogen and Sulfur (RoMANS II) study with field operations during November 2008 through November 2009 was designed to evaluate the composition and sources of reactive nitrogen in Rocky Mountain National Park, Colorado, USA. As part of RoMANS II, a mesoscale meteorological model was utilized to provide input for back trajectory and chemical transport models. Evaluation of the model's ability to capture important transport patterns in this region of complex terrain is discussed. Previous source-receptor studies of nitrogen in this region are also reviewed. Finally, results of several back trajectory analyses for RoMANS II are presented. The trajectory mass balance (TrMB) model, a receptor-based linear regression technique, was used to estimate mean source attributions of airborne ammonia concentrations during RoMANS II. Though ammonia concentrations are usually higher when there is transport from the east, the TrMB model estimates that, on average, areas to the west contribute a larger mean fraction of the ammonia. Possible reasons for this are discussed and include the greater frequency of westerly versus easterly winds, the possibility that ammonia is transported long distances as ammonium nitrate, and the difficulty of correctly modeling the transport winds in this area

Packages of Care for Attention-Deficit Hyperactivity Disorder in Low- and Middle-Income Countries

In the sixth in a series of six articles on packages of care for mental disorders in low- and middle-income countries, Alan Flisher and colleagues discuss the treatment of attention-deficit hyperactivity disorder

An enhanced alneal process to produce SRV < 1cm/s in 1 Ω cm n-type Si

The alneal is one of the most effective methods of electrically passivating a silicon surface, and has been used by numerous research groups since the 1980s. In this work, we present an enhanced alneal process that substantially improves its effectiveness. Previously, the success afforded by the standard alneal has been attributed to the chemical passivation provided by hydrogenation of the Si-SiO2 interface. However, the work presented here shows that it is possible to enhance the surface passivation by simultaneously introducing a component of Field Effect Passivation (FEP). Where the standard alneal is seen to provide lifetimes of ~2.1 ms, equivalent to a surface recombination velocity (SRV) of 3.3 cm/s, the enhanced alneal can provide a lifetime of 5.6 ms on 1 Ω cm, n-type Si, equivalent to a SRV 0.4 cm/s. The charge required for this enhanced passivation can be introduced in the order of minutes and has the potential to be introduced at the same time as the aluminium is deposited, thus, resulting in no extra processing time. Secondary ion mass spectroscopy showed that the nature of the charge is likely to be K and Na cations residing at the Si-SiO2 interface. The possibility of increasing the surface passivation beyond that of the standard alneal points to the importance of both chemical and field effect components of passivation, and is therefore of significant interest to high efficiency silicon solar cell research

Dataset associated with "Volatile organic compounds and ozone at four national parks in the southwestern United States"

Whole air canister samples were collected at four national parks in the southwestern United States. The parks are Carlsbad Caverns National Park (CAVE) in New Mexico, Grand Canyon National Park (GRCA) in Arizona, Great Basin National Park (GRBA) in Nevada, and Joshua Tree National Park (JOTR) in California. Sampling took place at each site from 4 April 2017 to 14 September 2017. In addition to these measurements, a short intensive study was conducted in and around CAVE in September 2017. This intensive included measurements from nearby Guadalupe Mountains National Park (GUMO) and Bitter Lake National Wildlife Refuge. Whole air samples were analyzed for 56 individual volatile organic compounds using a five-channel, three-GC (gas chromatograph) analytical system, which employed three flame ionization detectors (FIDs), one electron capture detector (ECD) and one mass spectrometer.This file contains the sample information and concentrations of data collected during a study to characterize volatile organic compounds at four national parks in the southwestern US. These data are associated with the manuscript: Benedict, K.B., Prenni, A.J. El-Sayed, M.M.H., Hecobian, A., Zhou, Y., Gebhart, K.A., Sive, B.C., Schichtel, B.A., Collett Jr, J.L., submitted. Volatile organic compounds and ozone at four national parks in the southwestern United States. Atmospheric Environment. The abstract from the submitted manuscript is as follows: The National Park Service is tasked with protecting the lands it oversees, including from impacts from air pollutants. While ozone is regularly monitored in many parks across the United States, precursors to ozone formation are not routinely measured. In this work we characterize volatile organic compounds (VOCs) at four national parks in the southwestern United States: Carlsbad Caverns (CAVE), Great Basin (GRBA), Grand Canyon (GRCA), and Joshua Tree (JOTR). Whole air samples were collected for VOC analysis for five months (mid-April through mid-September) in 2017. Samples were collected from 3 PM to 5 PM local time, corresponding approximately to the time of expected peak ozone concentrations, and were analyzed using gas chromatography for a variety of compounds including alkanes, alkenes, aromatics, biogenics, and alkyl nitrates. Among the four parks, the total measured VOC mixing ratio was greatest at CAVE, mostly due to an abundance of light alkanes (on average 94% of all VOCs measured) from oil and gas sources. VOC concentrations at the other three parks were similar to each other and approximately 7-10 times lower than at CAVE. While VOC sources varied across sites, VOC-OH reactivity was dominated by biogenic compounds at all sites except CAVE, which had similar contributions from biogenics and from light alkanes. To better characterize source influences, intensive measurements were conducted in and around CAVE for one week in September 2017. These measurements showed an oil and gas influence throughout the region and indicated that the whole air samples collected over the five-month study did not capture the full range of VOC mixing ratios present at other times of the day.This work was funded by the National Park Service. The CSU portion of the work was funded by Cooperative Agreement H2370094000, Task Agreement P13AC01187

Impact of Front Range sources on reactive nitrogen concentrations and deposition in Rocky Mountain National Park

Human influenced atmospheric reactive nitrogen (RN) is impacting ecosystems in Rocky Mountain National Park (ROMO). Due to ROMO’s protected status as a Class 1 area, these changes are concerning, and improving our understanding of the contributions of different types of RN and their sources is important for reducing impacts in ROMO. In July–August 2014 the most comprehensive measurements (to date) of RN were made in ROMO during the Front Range Air Pollution and Photochemistry Éxperiment (FRAPPÉ). Measurements included peroxyacetyl nitrate (PAN), C1–C5 alkyl nitrates, and high-time resolution NOx, NOy, and ammonia. A limited set of measurements was extended through October. Co-located measurements of a suite of volatile organic compounds provide information on source types impacting ROMO. Specifically, we use ethane as a tracer of oil and gas operations and tetrachloroethylene (C2Cl4) as an urban tracer to investigate their relationship with RN species and transport patterns. Results of this analysis suggest elevated RN concentrations are associated with emissions from oil and gas operations, which are frequently co-located with agricultural production and livestock feeding areas in the region, and from urban areas. There also are periods where RN at ROMO is impacted by long-range transport. We present an atmospheric RN budget and a nitrogen deposition budget with dry and wet components. Total deposition for the period (7/1–9/30) was estimated at 1.58 kg N/ha, with 87% from wet deposition during this period of above average precipitation. Ammonium wet deposition was the dominant contributor to total nitrogen deposition followed by nitrate wet deposition and total dry deposition. Ammonia was estimated to be the largest contributor to dry deposition followed by nitric acid and PAN (other species included alkyl nitrates, ammonium and nitrate). All three species are challenging to measure routinely, especially at high time resolution

Ammonia Dry Deposition in an Alpine Ecosystem Traced to Agricultural Emission Hotpots

Elevated reactive nitrogen (Nr) deposition is a concern for alpine ecosystems, and dry NH3 deposition is a key contributor. Understanding how emission hotspots impact downwind ecosystems through dry NH3 deposition provides opportunities for effective mitigation. However, direct NH3 flux measurements with sufficient temporal resolution to quantify such events are rare. Here, we measured NH3 fluxes at Rocky Mountain National Park (RMNP) during two summers and analyzed transport events from upwind agricultural and urban sources in northeastern Colorado. We deployed open-path NH3 sensors on a mobile laboratory and an eddy covariance tower to measure NH3 concentrations and fluxes. Our spatial sampling illustrated an upslope event that transported NH3 emissions from the hotspot to RMNP. Observed NH3 deposition was significantly higher when backtrajectories passed through only the agricultural region (7.9 ng m–2 s–1) versus only the urban area (1.0 ng m–2 s–1) and both urban and agricultural areas (2.7 ng m–2 s–1). Cumulative NH3 fluxes were calculated using observed, bidirectional modeled, and gap-filled fluxes. More than 40% of the total dry NH3 deposition occurred when air masses were traced back to agricultural source regions. More generally, we identified that 10 (25) more national parks in the U.S. are within 100 (200) km of an NH3 hotspot, and more observations are needed to quantify the impacts of these hotspots on dry NH3 deposition in these regions