A review on carbon emissions of global shipping

Carbon dioxide (CO2) emissions from shipping account for about 3% of total annual anthropogenic CO2 emissions and are assumed to increase markedly without mitigation measures. Following the introduction of the net-zero emissions target, the large uncertainties and challenges of a low-carbon transition in the shipping industry have raised concerns in the scientific community. This study presents a compressive review of CO2 emission inventories for the shipping industry, examines the historical CO2 emission trends and associated estimation uncertainties due to different methodologies, and further discusses the CO2 reduction measures and potential published in the literature. We aim to answer what has happened and what will happen in the shipping industry to identify potential challenges in realizing a roadmap to net-zero emissions. Here we show that there is a 20% variation in CO2 emissions reported by the reviewed inventories due to differences in estimation methodology and study scope, with top-down approaches (e.g., IEA) advancing the timeliness of emission estimation and bottom-up approaches (e.g., CAMS-GLOB-SHIP and EDGAR) facilitating the availability of geospatial information. The rebound in CO2 emissions by 2021 underscores the urgency of decoupling growth in seaborne trade from carbon emissions, and source and process control measures will provide most of the abatement potential, leaving the remaining abatement burden to be borne by carbon capture and out-of-industry transfers by 2050. However, secondary emissions, navigational safety, crew welfare, international cooperation, and economic and technical feasibility pose challenges to current low-carbon development. There remains a long way to go towards realizing the goal of the net-zero target, it requires the coordination and cooperation of all operators along the entire value chain of the shipping industry

First-principles Study of High-Pressure Phase Stability and Superconductivity of Bi4I4

Bismuth iodide Bi4I4 exhibits intricate crystal structures and topological insulating states that are highly susceptible to influence by environments, making its physical properties highly tunable by external conditions. In this work, we study the evolution of structural and electronic properties of Bi4I4 at high pressure using an advanced structure search method in conjunction with first-principles calculations. Our results indicate that the most stable ambient-pressure monoclinic α−Bi4I4 phase in C2/m symmetry transforms to a trigonal P31c structure (ɛ−Bi4I4) at 8.4 GPa, then to a tetragonal P4/mmm structure (ζ−Bi4I4) above 16.6 GPa. In contrast to the semiconducting nature of ambient-pressure Bi4I4, the two high-pressure phases are metallic, in agreement with reported electrical measurements. The ɛ−Bi4I4 phase exhibits distinct ionic states of Iδ− and (Bi4I3)δ + (δ=0.4123 e), driven by a pressure-induced volume reduction. We show that both ɛ- and ζ−Bi4I4 are superconductors, and the emergence of pressure-induced superconductivity might be intimately linked to the underlying structural phase transitions

Utilizing the Systematic Literature Review in Aviation -- A Case Study for Runway Incursions

This research presents the process for a systematic literature review examining factors that contribute to runway incursions (RIs). A systematic literature review uses other research results as data for systematic analysis. Runway safety is a top priority. In the US, RIs have been increasing and typically three RIs occur every day. This paper identified 134 articles using 22 databases. Filtering criteria and analysis identified six contributing categories: human factors, airport geometry, technical factors, airport characteristics, environmental factors, and organizational factors. Recommendations for reduction of RIs and suggestions for further studies are presented based on these factors

Animal waste use and implications to agricultural greenhouse gas emissions in the United States

Acknowledgements: Z. Q. and S. D. have been partially supported by the National Basic Research Program of China (2016YFA0602701), the National Natural Science Foundation of China (41975113), and the Guangdong Provincial Department of Science and Technology (2019ZT08G090). The input of P. S. contributed to the following projects: DEVIL (NE/M021327/1) and Soils-R-GRREAT (NE/P019455/1). Data availability: The data that support the findings of this study are openly available at the following URL/DOI: https://greet.es.anl.gov/. Publisher Copyright: © 2021 The Author(s). Published by IOP Publishing Ltd. Creative Commons Attribution 4.0 license, Original content from this work may be used under the terms of the . Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.Peer reviewedPublisher PD

Pressure-induced transitions in FePS3_3: Structural, magnetic and electronic properties

FePS$_3$ is a prototype van der Waals layered antiferromagnet and a Mott insulator under ambient conditions, which has been recently reported to go through a pressure-induced dimensionality crossover and an insulator-to-metal transition. These transitions also lead to the appearance of a novel magnetic metallic state. To further understand these emergent structural and physical properties, we have performed a first-principles study using van der Waals and Hubbard $U$ corrected density functional theory including a random structure search. Our computational study attempts to interpret the experimental coexistence of the low- and intermediate-pressure phases and we predict a novel high-pressure phase with distinctive dimensionality and different possible origins of metallicity.Comment: Re-Submission to SciPos

Learning Multiscale Consistency for Self-supervised Electron Microscopy Instance Segmentation

Instance segmentation in electron microscopy (EM) volumes is tough due to complex shapes and sparse annotations. Self-supervised learning helps but still struggles with intricate visual patterns in EM. To address this, we propose a pretraining framework that enhances multiscale consistency in EM volumes. Our approach leverages a Siamese network architecture, integrating both strong and weak data augmentations to effectively extract multiscale features. We uphold voxel-level coherence by reconstructing the original input data from these augmented instances. Furthermore, we incorporate cross-attention mechanisms to facilitate fine-grained feature alignment between these augmentations. Finally, we apply contrastive learning techniques across a feature pyramid, allowing us to distill distinctive representations spanning various scales. After pretraining on four large-scale EM datasets, our framework significantly improves downstream tasks like neuron and mitochondria segmentation, especially with limited finetuning data. It effectively captures voxel and feature consistency, showing promise for learning transferable representations for EM analysis

A novel MR device with variable stiffness and damping capability

This paper proposes a novel device based on the Magnetorheological (MR) fluid which has the capability to change stiffness and damping under control. MR fluid is a type of smart material whose properties could be controlled by the external magnetic field. Most of MR devices are MR dampers, which normally are used as variable damping devices. The presented device consists of two hydro-cylinder-spring structures and one MR valve linking these two structures. The rheological characteristics of MR fluid in the fluid flow channels of MR valve are controlled by the strength of magnetic fields, which directly affect the link conditions. The equivalent stiffness and damping coefficients of the device thus varies with the rheological characteristics of MR fluid simultaneously. A mathematical model is established to describe the properties of the proposed device based on the Bouc-wen model. The mathematical model the simulation results indicate that the proposed device can control both the stiffness and damping which has potential to be applied for restrain vibration mitigation efficiently

Biomechanical analysis of the Maxillary Sinus Floor Membrane During internal Sinus Floor Elevation With Implants at Different angles of the Maxillary Sinus angles

OBJECTIVE: This study analyzed and compared the biomechanical properties of maxillary sinus floor mucosa with implants at three different maxillary sinus angles during a modified internal sinus floor elevation procedure. METHODS: 3D reconstruction of the implant, maxillary sinus bone, and membrane were performed. The maxillary sinus model was set at three different angles. Two internal maxillary sinus elevation models were established, and finite element analysis was used to simulate the modified maxillary sinus elevation process. The implant was elevated to 10 mm at three maxillary sinus angles when the maxillary sinus floor membrane was separated by 0 and 4 mm. The stress of the maxillary sinus floor membrane was analyzed and compared. RESULTS: When the maxillary sinus floor membrane was separated by 0 mm and elevated to 10 mm, the peak stress values of the implant on the maxillary sinus floor membrane at three different angles were as follows: maxillary sinus I: 5.14-78.32 MPa; maxillary sinus II: 2.81-73.89 MPa; and maxillary sinus III: 2.82-51.87 MPa. When the maxillary sinus floor membrane was separated by 4 mm and elevated to 10 mm, the corresponding values were as follows: maxillary sinus I: 0.50-7.25 MPa; maxillary sinus II: 0.81-16.55 MPa; and maxillary sinus III: 0.49-22.74 MPa. CONCLUSION: The risk of sinus floor membrane rupture is greatly reduced after adequate dissection of the maxillary sinus floor membrane when performing modified internal sinus elevation in a narrow maxillary sinus. In a wide maxillary sinus, the risk of rupture or perforation of the wider maxillary sinus floor is reduced, regardless of whether traditional or modified internal sinus elevation is performed at the same height