Automotive electrification holds the promise of mitigating transportation-related greenhouse gas (GHG) emissions, yet at the expense of growing demand for critical metals. Here, we analyze the ...trade-off between the decarbonization potential of the road transportation sector and its critical metal requirement from the demand-side perspective in 48 major countries committing to decarbonize their road transportation sectors aided by electric vehicles (EVs). Our results demonstrate that deploying EVs with 40-100% penetration by 2050 can increase lithium, nickel, cobalt, and manganese demands by 2909-7513%, 2127-5426%, 1039-2684%, and 1099-2838%, respectively, and grow platinum group metal requirement by 131-179% in the 48 investigated countries, relative to 2020. Higher EV penetration reduces GHG emissions from fuel use regardless of the transportation energy transition, while those from fuel production are more sensitive to energy-sector decarbonization and could reach nearly "net zero" by 2040.
Epilepsy is the most common serious chronic neurological disorder. Current data show that one-third of patients do not respond to anti-epileptic drugs (AEDs). Most non-responsive epilepsy patients ...are resistant to several, often all, AEDs, even though the drugs differ from each other in pharmacokinetics, mechanisms of action, and interaction potential. The mechanisms underlying drug resistance of epilepsy patients are still not clear. In recent years, one of the potential mechanisms interesting researchers is over-expression of P-glycoprotein (P-gp, also known as ABCB1 or MDR1) in endothelial cells of the blood–brain barrier (BBB) in epilepsy patients. P-gp plays a central role in drug absorption and distribution in many organisms. The expression of P-gp is greater in drug-resistant than in drug-responsive patients. Some studies also indicate that several AEDs are substrates or inhibitors of P-gp, implying that P-gp may play an important role in drug resistance in refractory epilepsy. In this article, we review the clinical and laboratory evidence that P-gp expression is increased in epileptic brain tissues and that AEDs are substrates of P-gp in vitro and in vivo. We discuss criteria for identifying the substrate status of AEDs and use structure–activity relationship (SAR) models to predict which AEDs act as P-gp substrates.
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Building stock growth around the world drives extensive material consumption and environmental impacts. Future impacts will be dependent on the level and rate of socioeconomic development, along with ...material use and supply strategies. Here we evaluate material-related greenhouse gas (GHG) emissions for residential and commercial buildings along with their reduction potentials in 26 global regions by 2060. For a middle-of-the-road baseline scenario, building material-related emissions see an increase of 3.5 to 4.6 Gt CO2eq yr-1 between 2020-2060. Low- and lower-middle-income regions see rapid emission increase from 750 Mt (22% globally) in 2020 and 2.4 Gt (51%) in 2060, while higher-income regions shrink in both absolute and relative terms. Implementing several material efficiency strategies together in a High Efficiency (HE) scenario could almost half the baseline emissions. Yet, even in this scenario, the building material sector would require double its current proportional share of emissions to meet a 1.5 °C-compatible target.
A three-dimensional (3-D) finite element model has been developed to simulate the coupled thermal-mechanical fields in ultrasonic welding of aluminum foils. Transient distributions and evolution of ...the in-process variables, including normal stress, shear stress, slide distance, heat generation, temperature, and plastic deformation on the contact interface, and their interactions have been studied in detail. The von Mises plastic strain from the simulation has been correlated with the measured bonded area of ultrasonic joints. A possible mechanism for ultrasonic bond formation is proposed. The severe, localized, plastic deformation at the bond region is believed to be the major phenomenon causing bond formation in ultrasonic welding.
•A transferable residential space heating energy model is developed based on geo-referenced data and archetypes.•Model results are spatially validated against measured energy consumption.•Past ...refurbishment and occupant behavior significantly affect model results.•The model is suited to identify spatial hotspots and assess energy-efficiency measures.
High spatial resolution is critical for a building stock energy model to identify spatial hotspots and provide targeted recommendations for reducing regional energy consumption. However, input uncertainties due to lacking high-resolution spatial data (e.g. building information and occupant behavior) can cause great discrepancies between modeled and actual energy consumption. We present a modeling framework that can act as a blueprint model for most European countries based on geo- referenced data, building archetypes, and public algorithms. Further sophistication is added in a step-wise approach, including the shift from average to hourly weather data, refurbishment, and occupants’ heating schedules. The model is demonstrated for the city of Leiden, the Netherlands, and the simulated results are spatially validated against the measured natural gas consumption reported at postcode level. Results show that when these factors are considered, the model can provide a good estimate of the energy consumption at the city scale (overestimated by 6%). At postcode level, nearly 83% of the absolute differences between modeled and measured natural gas consumption are within one standard deviation (±25 kWh/m2a, about 30% of the mean measured natural gas consumption). Further research and data would be required to provide reliable results at the level of individual buildings, e.g. information on refurbishment and occupant behavior. The model is well suited to identify spatial hotspots of residential energy consumption and could thus provide a practical basis (e.g. maps) for targeted measures to mitigate climate change.
•A quantitative analysis of the research scopes and methods of 78 publications.•Projections of annual and cumulative critical metal requirements are compared.•Global critical metal reserves will not ...meet their long-term cumulative demands.•Relevant policies for securing future critical metal supply are classified.
The clean energy transition plays an essential role in achieving climate mitigation targets. As for the transportation sector, battery and fuel cell electric vehicles (EVs) have emerged as a key solution to reduce greenhouse gasses from transportation emissions. However, the rapid uptake of EVs has triggered potential supply risks of critical metals (e.g., lithium, nickel, cobalt, platinum group metals (PGMs), etc.) used in the production of lithium-ion batteries and fuel cells. Material flow analysis (MFA) has been widely applied to assess the demand for critical metals used in transportation electrification on various spatiotemporal scales. This paper presents a quantitative review and analysis of 78 MFA research articles on the critical metal requirement of transportation electrification. We analyzed the characteristics of the selected studies regarding their geographical and temporal scopes, transportation sectors, EV categories, battery technologies, materials, and modeling approaches. Based on the global forecasts in those studies, we compared the annual and cumulative global requirements of the four metals that received the most attention: lithium, nickel, cobalt, and PGMs. Although major uncertainties exist, most studies indicate that the annual demand for these four metals will continue to increase and far exceed their production capacities in 2021. Global reserves of these metals may meet their cumulative demand in the short-term (2020–2030) and medium-term (2020–2050) but are insufficient for the long-term (2020–2100) needs. Then, we summarized the proposed policy implications in these studies. Finally, we discuss the main findings from the four aspects: environmental and social implications of deploying electric vehicles, whether or not to electrify heavy-duty vehicles, opportunities and challenges in recycling, and future research direction.
In the present work, the wettability of defective graphene oxide (GO) film is studied by molecular dynamics simulations. A water droplet is deposited on the surface of a graphene oxide membrane, and ...the contact angle is measured by fitting the liquid⁻vapor interface. Although pristine graphene has few hydrophobic properties with a contact angle of 95°, graphene oxide presents more hydrophilic properties, due to the stronger hydrogen bonds interactions at the interface. Moreover, the introduction of vacancy defects at the graphene oxide surface decreases the wettability of graphene oxide. We find that the contact angle of graphene oxide increases from 70° to 82°, with a defective concentration from 0% to 10%. Our results will help provide a new method for controlling the wetting properties of GO and its additional capabilities in device design for applications.
A novel miniaturized tri-band frequency selective surface (FSS) based on convoluted design has been proposed in this letter. The proposed FSS is a low-profile structure, and it is composed of two ...periodic metallic arrays separated by a thin dielectric substrate. The top metallic array is composed of four branched spiral triangles connected in the center, and the bottom one is consisting of gridded tortuous cross-dipole. The proposed FSS can provide three passbands operating at 3.28, 4.2, and 5.4 GHz, respectively. The unit cell is only 0.066 λ 0 × 0.066 λ 0 in size, where λ 0 is the wavelength of the first resonant frequency in free space. In addition, the proposed FSS provides a stable performance under oblique incidence for both TE and TM polarizations. For verification, an FSS prototype has been fabricated and measured. Good agreements between the simulated and the measured results can be observed.
We studied the crystallization of nearly "homogeneous" polyethylene glycol (PEG) networks prepared by end-crosslinking of tetra-armed PEG. The influence of stretching ratio and strand length on the ...melting and crystallization temperature was investigated. The relation of melting temperature and elongation ratio verifies the thermodynamic theories of strain-induced polymer crystallization.
The thermodynamic theories of strain-induced polymer crystallization have been verified using nearly "homogeneous" polyethylene glycol (PEG) networks.
The as-welded microstructure of laser-welded Ti-6Al-4V is characterized as a function of CO2 key-hole mode laser welding speed. Martensitic α′ is the predominant phase, with some α and retained β. ...Phase transformation is affected by the cooling rate through laser welding speed. A higher welding speed of 1.6 to 2.0m/min produced more martensite α′ and less retained β in the welds. 1.4m/min welding speed produced small amounts of α, besides the martensite α′. A trace of δ titanium hydride phase seems to have formed in the weld fusion zone. Moiré fringes are a common feature in the TEM microstructure, due to abundance of multi-phase interfaces. Tensile twins and clusters of dislocations indicate that plastic deformation has happened in the as-welded microstructure, indicating the local stress levels to be approaching the yield stress on-cooling during laser welding.
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