bluuebunny/crossref_metadata_2025 huggingface dataset:
Calcite-functionalized micromodels for pore-scale investigations of CO2 storage security
Authors: Haugen Malin , Benali Benyamine , Føyen Tore , Song Wen , Fernø Martin A. , Brattekås Bergit
Published: January 2023

Carbon capture and subsequent storage (CCS) is identified as a necessity to achieve climate commitments. Permanent storage of carbon dioxide (CO2) in subsurface saline aquifers or depleted oil and gas reservoirs is feasible, but large-scale implementation of such storage has so far been slow. Although sandstone formations are currently most viable for CO2 sequestration, carbonates play an important role in widespread implementation of CCS; both due to the world-wide abundancy of saline aquifers in carbonate formations, and as candidates for CO2-EOR with combined storage. Acidification of formation brine during CO2 injection cause carbonate dissolution and development of reactive flow patterns. Using calcite-functionalization of micromodels we experimentally investigate fundamental pore-scale reactive transport dynamics relevant for carbonate CO2 storage security. Calcite-functionalized, two-dimensional and siliconbased, pore scale micromodels were used. Calcite precipitation was microbially induced from the bacteria Sporosarcina pasteurii and calcite grains were formed in-situ. This paper details an improved procedure for achieving controlled calcite precipitation in the pore space and characterizes the precipitation/mineralization process. The experimental setup featured a temperature-controlled micromodel holder attached to an automatic scanning stage. A high-resolution microscope enabled full-model (22x27 mm) image capture at resolution of 1.1 µm/pixel within 82 seconds. An in-house developed image-analysis python script was used to quantify porosity alterations due to calcite precipitation. The calcite-functionalized micromodels were found to replicate natural carbonate pore geometry and chemistry, and thus may be used to quantify calcite dissolution and reactive flow at the pore-scale.
Dynamic pore-scale modeling of residual fluid configurations in disordered porous media
Authors: Gong Yanbin , Sedghi Mohammad , Piri Mohammad
Published: January 2023

Fluid trapping in porous media is important in many subsurface flow processes such as enhanced oil recovery and geological sequestration of carbon dioxide. To achieve optimal performance in such applications, a fundamental understanding of residual trapping mechanisms at the pore scale is necessary. In this work, we present a computational study of fluid trapping behaviors in natural porous media under different flow regimes by employing a dynamic pore-network modeling approach. The model incorporates many advanced features that have not been collectively used in previous dynamic platforms. For instance, it rigorously solves for fluid pressure fields from two-phase mass balance equations in each pore element, incorporates a detailed description of pore-scale fluid displacement dynamics of piston-like advance, snap-off, and pore-body filling, and explicitly accounts for flow through wetting layers forming in corners and rough surfaces of pore spaces. Moreover, we extend the ability of our model by including contact angle hysteresis, which is often neglected in existing dynamic models. A heavily-parallelized implementation of this platform is further advanced to achieve an efficient computational performance. We first conduct primary drainage and imbibition simulations in pore networks representing Bentheimer and Berea sandstones. We show that the predicted two-phase relative permeability curves agree well with their experimental counterparts reported in the literature. Afterwards, the validated model is used to systematically probe fluid trapping behaviors in a core-sized pore network that is constructed from high-resolution micro-computed tomography images of a Berea sandstone core sample. The effects of dynamic flow conditions and fluid properties on core-scale two-phase displacement pattern, residual-fluid configuration, and residual oil saturations are examined in detail. Fluid trapping properties such as maximum and average residual-fluid cluster size and capillary-controlled invasion selectivity at the pore scale are analyzed under both capillaryand viscous-dominated flow regimes.
Barium cerate and its composite perovskites – synthesis techniques: a comprehensive review
Authors: Jasira Seere Valappil , Veena Vannadil Puthiyaveetil , Shilpa Cherlan Kottianmadathil , Nissamudeen Kavukuzhi Meerasahib
Published: January 2023

Perovskites have attracted growing interest in recent eras due to their unique properties and potential applications. Barium cerate (BC) proton-conducting perovskites have been examined over decades for various applications such as hydrogen sensors, fuel cells, proton separation membranes, etc. When compared with oxide ion conductors under the same circumstances, ceramic proton conducting barium cerate can diminish the working temperature of solid oxide fuel cells to an intermediate temperature range, 673–873 K because of their higher ionic conduction. The present review carefully analyses and summarizes different synthesis approaches with optimization conditions to prepare BC-derived perovskites and the reported data have been carefully analyzed. A range of synthesis methods such as solid-state reaction method and wet chemical processes like coprecipitation, combustion, Pechini method, etc., have been systematically investigated. Even though the solid-state method has considerable disadvantages, most researchers avoid its incompetence due to the easiness of processing. Applications of the material have been briefly deliberated to exemplify its technological importance. The present review concluded with the recent signs of progress and innovative techniques employed to overcome the processing complications in these materials.
Effect of Sn on formation and transformation of VO2 phase
Authors: Dong Hao-nan , Shang De-li , Lu Yan-qing , Li Yu-tong , Wu Fa-yu , Zhang Jun-wei
Published: January 2023

The role of stannum was investigated in formation and transformation of vanadium-dioxide phase in a deep perspective through characterization methods including Raman spectra, XRD, OM, SEM, UV–vis and electrochemical workstation. The result showed supersaturated stannum atoms could exist in SnxV2-xO5 as amorphous solid solution through non-equilibrium sputtering method, by which the unitary phase Sn-doped VO2 could be obtained under either thermal de-oxidation or thermal de-composition mechanism. Furthermore, cooperating stannum atoms with oxygen vacancies could regulate the formation of vanadium dioxide M1 or M2 phase, in turn engineer the phase transformation (M-R) temperature of VO2.
Insights into circular material and waste flows from c-Si PV industry
Authors: Brailovsky Peter , Baumann Kerstin , Held Michael , Briem Ann-Kathrin , Wambach Karsten , Gervais Estelle , Herceg Sina , Mertvoy Boris , Nold Sebastian , Rentsch Jochen
Published: January 2023

A material flow model for the production of Bifacial Selective Emitter 60-cell p-type Cz PERC (Passivated Emitter and Rear Contacted) glass-backsheet modules with aluminium frame was built. The selected module represents mature technologies in the PV industry and their manufacturing is considered to take place in China in a production cluster with an annual module capacity of 5 GWp. In a first step, data acquisition and validation for wafer, cell and module fabs took place. The data were used to generate the reference system lifecycle inventories (LCI) and extended waste databases for the reference wafers, cells and modules. A set of potential circularity actions, such as the vertical integration of the operations and waste revalorisation strategies, had been proposed and their environmental performance and cost assessed by means of a life cycle assessment (LCA) and a total cost of ownership (TCO). Our results show that 87% of the waste can be reduced and revalorised, this represents a circular flow of raw materials of 18,756 Mg per year from a 5GWp PV module production cluster. Environmental impact reductions of 0.6–2.3% are estimated for different impact categories. We also estimate a cost reduction potential of 2.59% from total module costs.
Clinical Assessment for Lower Eyelid Blepharoplasty with Attention on Negative Prognostic Indicators
Authors: Vroegop Anneclaire V. , Faris Callum
Published: January 2023

In the present report, a comprehensive approach on the assessment of the lower eyelid for blepharoplasty is provided. Important items such as anatomical key areas and surgical factors are discussed. Proper management of lower eyelid deformities requires an understanding of both intrinsic and extrinsic anatomical factors resulting in the unfavorable outcome.
Asynchronous x-ray multiprobe data acquisition for x-ray transient absorption spectroscopy
Authors: Kinigstein Eli Diego , Otolski Christopher , Jennings Guy , Doumy Gilles , Walko Donald A. , Zuo Xiaobing , Guo Jinghua , March Anne Marie , Zhang Xiaoyi
Published: January 2023

Laser pump X-ray Transient Absorption (XTA) spectroscopy offers unique insights into photochemical and photophysical phenomena. X-ray Multiprobe data acquisition (XMP DAQ) is a technique that acquires XTA spectra at thousands of pump-probe time delays in a single measurement, producing highly self-consistent XTA spectral dynamics. In this work, we report two new XTA data acquisition techniques that leverage the high performance of XMP DAQ in combination with High Repetition Rate (HRR) laser excitation: HRR-XMP and Asynchronous X-ray Multiprobe (AXMP). HRR-XMP uses a laser repetition rate up to 200 times higher than previous implementations of XMP DAQ and proportionally increases the data collection efficiency at each time delay. This allows HRR-XMP to acquire more high-quality XTA data in less time. AXMP uses a frequency mismatch between the laser and x-ray pulses to acquire XTA data at a flexibly defined set of pump-probe time delays with a spacing down to a few picoseconds. AXMP introduces a novel pump-probe synchronization concept that acquires data in clusters of time delays. The temporally inhomogeneous distribution of acquired data improves the attainable signal statistics at early times, making the AXMP synchronization concept useful for measuring sub-nanosecond dynamics with photon-starved techniques like XTA. In this paper, we demonstrate HRR-XMP and AXMP by measuring the laser-induced spectral dynamics of dilute aqueous solutions of Fe(CN)64− and [FeII(bpy)3]2+ (bpy: 2,2′-bipyridine), respectively.
Conformal Yang–Baxter equation on Cur(sl2(C))
Authors: Gubarev Vsevolod , Kozlov Roman
Published: January 2023

In 2008, Liberati [J. Algebra 319, 2295–2318 (2008)] defined what a conformal Lie bialgebra is and introduced the conformal classical Yang–Baxter equation (CCYBE). An L-invariant solution to the weak version of CCYBE provides a conformal Lie bialgebra structure. We describe all solutions to the CCYBE on the current Lie conformal algebra Cur(sl2(C)) and to the weak version of it.
Current perspective in magnetocaloric materials research
Authors: Law Jia Yan , Moreno-Ramírez Luis M. , Díaz-García Álvaro , Franco Victorino
Published: January 2023

Magnetocaloric refrigeration has remained a promising alternative to conventional refrigeration for the last few decades. The delay in reaching the market is significantly based on materials’ related issues, such as hysteresis/reversibility, mechanical stability, or formability. This perspective paper shows the current trends in magnetocaloric materials research, highlighting the families of alloys and compounds that are gaining attention in the recent years. It also includes an overview of novel approaches that can be used to analyze these properties that could improve the applicability of magnetocaloric materials.
Numerical investigation of flow past a circular cylinder modified with a single groove at low Reynolds number
Authors: Priyadarsan Ashutosh , Afzal Mohammad Saud
Published: January 2023

Flow past a circular cylinder modified by grooves is one of the passive control techniques to control the drag and lift forces. The presence of grooves tends to reduce the hydrodynamic drag and lift. The aim of this work was to numerically investigate the influence of a single groove modification on a circular cylinder and how it was impacting the hydrodynamic coefficients based on its position and shape at low Reynolds numbers. Three types of grooves were considered, namely, dimple, square, and triangular, with identical width and depth which is 0.1 times the diameter. The Reynolds numbers considered were 100, 150, and 200. The computational domain was set to a blockage ratio of 0.01 after carrying out a detailed domain independence test. It was observed that the drag and lift reduction was maximum at groove location 90° with the decrements being more for the square groove shape. The viscous drag showed a decrease in its values for all the groove positions located on the flow-facing side of the cylinder; however, the pressure drag showed an increment in its values for these groove locations, and these increments were relative of larger magnitudes, thus influencing a net increase in the total mean drag when compared to the smooth case; this was evident at groove locations 120° and 150°. The vorticity patterns for the grooves located on the front side showed large irregularities in magnitude between the anticlockwise and the clockwise vortices with the groove side vortices being of larger magnitudes, and for the wake side, the irregularities were negligible. The coefficient of pressure and separation angles were also investigated. The CP vs θ plots showed discontinuity at groove locations with abrupt variations at the front face of the cylinder; for the wake side grooves, these discontinuities were low and almost coincided with the CP vs θ plots of the smooth cylinder. The grooves located at 90° showed a delay in separation and at 60° the boundary layer tends to detach earlier.
Influence of magnetic dipole on ferrohydrodynamic thin film flow over an inclined spinning surface
Authors: Bhandari Anupam , Parmar K. P. S.
Published: January 2023

This study investigates the three-dimensional problem of steady ferrofluid deposition on an inclined rotating surface in the presence of a magnetic dipole. A finite element procedure is used to solve normalized ordinary differential equations derived from momentum and energy equations. The current numerical model and its solution is compared and validated against previous numerical results. The velocity and temperature field variations are a representation of the effects of magnetic field-based viscosity, magnetic polarization force, Curie temperature, and Prandtl number. In addition, some common errors in the similarity transformation for inclined rotating disk flows are addressed in the present study. The results show that the magnetic field-dependent viscosity generated by the magnetic torque in the current flow reduces the velocity of the thin film liquid in all directions, including rotational flow (radial, tangential, and axial) and inclined flow (drainage and induced). Moreover, the local heat transfer between the fluid and the surface of the rotating disk increases with a rise in the ferromagnetic interaction number and Prandtl number. These findings imply that ferrofluids could be effective for cooling electronic devices in the presence of a magnetic dipole.
Mode transition in fluid–structure interaction of piezoelectric membrane wings
Authors: Xia Yingjie , Huang Guangjing , Dai Yuting , Yang Chao , Wu You
Published: January 2023

Flow-induced vibrations can be utilized to harvest energy for micro-air vehicles (MAVs). A flexible membrane wing with an embedded piezoelectric energy harvester at an angle of attack of 12° and the Reynolds number (Re) of 8000 is studied by numerical simulations. An aero-electro-mechanical model is established to investigate the effect of the leading-edge (LE) and trailing-edge (TE) geometries on the fluid–structure interaction (FSI) modes, aerodynamic performance, and energy harvesting performance. A new correction method of structural frequency is proposed that it considers both the aerodynamic stiffness effect and the added mass effect corresponding to a specific FSI mode of interest. The results suggest that the mode transition accompanied by the performance changes is essentially caused by the FSI state transition, which is distinguished by the corrected structural frequency and the vortex shedding one. With the Fourier mode decomposition (FMD) method, the modes of membrane vibration and pressure fluctuation become clear. The LE geometry is found to affect the FSI state by influencing the leading-edge vortices, which further triggers the mode transition.
Enhanced Sampling Based on Collective Variables
Authors: Fu Haohao , Cai Wensheng , Chipot Christophe , Shao Xueguang
Published: January 2023

On general-purpose hardware, the timescale amenable to molecular dynamics (MD) simulations is usually microseconds. When investigating rare events that fall beyond the scope of MD, one possible way to boost up the exploration, or sampling, of the configurational space consists in using enhanced-sampling algorithms. In this chapter, we introduce the theoretical background of popular enhanced sampling techniques based on collective variables (CVs), such as umbrella sampling, adaptive biasing force, metadynamics and their variants. We then provide a step-by-step protocol to illustrate how to carry out an enhanced-sampling simulation to capture the rare events by means of MD simulations. The use of both the Colvars (supported by NAMD, LAMMPS and Gromacs) and Plumed (supported by NAMD, LAMMPS, Gromacs, Amber, OpenMM, etc.) modules to carry out CV-based enhanced-sampling simulations is introduced. Finally, we discuss the matters that require attention in the practical study of coupled movements in complex (bio)chemical molecular objects.
A Step-by-Step Guide on How to Construct Quasi-Markov State Models to Study Functional Conformational Changes of Biological Macromolecules
Authors: Yik Andrew Kai-Hei , Qiu Yunrui , Unarta Ilona Christy , Cao Siqin , Huang Xuhui
Published: January 2023

Conformational changes play an important role for many biomolecules to perform their functions. In recent years, Markov State Model (MSM) has become a powerful tool to investigate these functional conformational changes by predicting long timescale dynamics from many short molecular dynamics (MD) simulations. In MSM, dynamics are modelled by a first-order master equation, in which a biomolecule undergoes Markovian transitions among conformational states at discrete-time intervals, called lag time. The lag time has to be sufficiently long to build a Markovian model, but this parameter is often bound by the length of MD simulations available for estimating the frequency of interstate transitions. To address this challenge, we recently employed the generalized master equation (GME) formalism (e.g., the quasi-Markov State Model or qMSM) to encode non-Markovian dynamics in a time-dependent memory kernel. When applied to study protein dynamics, our qMSM can be built from MD simulations that are an order-of-magnitude shorter than MSM would have required. The construction of qMSM is more complicated than that of MSM, as time-dependent memory kernels need to be properly extracted from the MD simulation trajectories. In this chapter, we will present a step-by-step guide on how to build qMSM from MD simulation datasets, and the accompanying materials are publicly available on Github: https://github.com/ykhdrew/qMSM_tutorial. We hope this tutorial is useful for researchers who want to apply qMSM and study functional conformational changes in biomolecules.
Two-dimensional constrained chaos and industrial revolution cycles
Authors: Yano Makoto , Furukawa Yuichi
Published: January 2023

Since the 1760s, at least three industrial revolutions have occurred. To explain this phenomenon, we introduce two-dimensional (2D) constrained chaos. Using a model of innovation dynamics, we show that an industrial-revolution-like technology burst, driven by investment/saving motives for R&D activities, recurs about every one hundred years if the monopolistic use of a new technology lasts about 8 y.
The role of baroclinic activity in controlling Earth’s albedo in the present and future climates
Authors: Hadas Or , Datseris George , Blanco Joaquin , Bony Sandrine , Caballero Rodrigo , Stevens Bjorn , Kaspi Yohai
Published: January 2023

Clouds are one of the most influential components of Earth’s climate system. Specifically, the midlatitude clouds play a vital role in shaping Earth’s albedo. This study investigates the connection between baroclinic activity, which dominates the midlatitude climate, and cloud-albedo and how it relates to Earth’s existing hemispheric albedo symmetry. We show that baroclinic activity and cloud-albedo are highly correlated. By using Lagrangian tracking of cyclones and anticyclones and analyzing their individual cloud properties at different vertical levels, we explain why their cloud-albedo increases monotonically with intensity. We find that while for anticyclones, the relation between strength and cloudiness is mostly linear, for cyclones, in which clouds are more prevalent, the relation saturates with strength. Using the cloud-albedo strength relationships and the climatology of baroclinic activity, we demonstrate that the observed hemispheric difference in cloud-albedo is well explained by the difference in the population of cyclones and anticyclones, which counter-balances the difference in clear-sky albedo. Finally, we discuss the robustness of the hemispheric albedo symmetry in the future climate. Seemingly, the symmetry should break, as the northern hemisphere’s storm track response differs from that of the southern hemisphere due to Arctic amplification. However, we show that the saturation of the cloud response to storm intensity implies that the increase in the skewness of the southern hemisphere storm distribution toward strong storms will decrease future cloud-albedo in the southern hemisphere. This complex response explains how albedo symmetry might persist even with the predicted asymmetric hemispheric change in baroclinicity under climate change.
Time series transcriptome analysis implicates the circadian clock in the
Drosophila melanogaster
female’s response to sex peptide
Authors: Delbare Sofie Y. N. , Venkatraman Sara , Scuderi Kate , Wells Martin T. , Wolfner Mariana F. , Basu Sumanta , Clark Andrew G.
Published: January 2023

Sex peptide (SP), a seminal fluid protein of 
Drosophila melanogaster
males, has been described as driving a virgin-to-mated switch in females, through eliciting an array of responses including increased egg laying, activity, and food intake and a decreased remating rate. While it is known that SP achieves this, at least in part, by altering neuronal signaling in females, the genetic architecture and temporal dynamics of the female’s response to SP remain elusive. We used a high-resolution time series RNA-sequencing dataset of female heads at 10 time points within the first 24 h after mating to learn about the genetic architecture, at the gene and exon levels, of the female’s response to SP. We find that SP is not essential to trigger early aspects of a virgin-to-mated transcriptional switch, which includes changes in a metabolic gene regulatory network. However, SP is needed to maintain and diversify metabolic changes and to trigger changes in a neuronal gene regulatory network. We further find that SP alters rhythmic gene expression in females and suggests that SP’s disruption of the female’s circadian rhythm might be key to its widespread effects.
Politeness in Catalan Sign Language (LSC)
Authors: Moya-Avilés Berta , Barberà Gemma , Bach Carme
Published: January 2023

This paper focuses on politeness in Catalan Sign Language (LSC), concretely on criticisms. The main goal is to analyze linguistic mitigation, specifically through the discourse strategy that consists of expressions for restricting opinions. The data comes from a TV show in LSC, which features real and spontaneous productions of Deaf adult signers. The results show the existence of three different strategies: lexical units that work as hedges of subjectivization, the use of the first-person pronoun to emphasize the personal point of view, and the use of the vertical palm sign with a mitigating function. Moreover, particular non-manual markers are also involved, namely, shrugs, head tilts or raised eyebrows, which work at the prosodic and pragmatic level for mitigation purposes.
Multimodality and subtitles
Authors: Claudel Chantal
Published: January 2023

This article examines, in a corpus of eight mainstream Japanese films with French subtitles, the forms of realization of certain im/polite Japanese multimodal behaviors (verbal rituals, kneeling, bowing, clothing, deferential vs casual attitude), and also the impact of the contextual environment on the choices made by the subtitlers. It shows the importance of multimodality for the non-Japanese spectator who, due to a non-overlap between the formulas of each language and/or in the absence of subtitles, can rely on these nonverbal and situational elements to re-establish the gap between the source language-culture and the target language-culture, to interpret the degree of deference that exists between the characters and/or to imagine the forms of realization of the asymmetry of the relationships.
STING trafficking as a new dimension of immune signaling
Authors: Jeltema Devon , Abbott Kennady , Yan Nan
Published: January 2023

The cGAS–STING pathway is an evolutionarily conserved immune signaling pathway critical for microbial defense. Unlike other innate immune pathways that largely rely on stationary cascades of signaling events, STING is highly mobile in the cell. STING is activated on the ER, but only signals after it arrives on the Golgi, and then it is quickly degraded by the lysosome. Each step of STING trafficking through the secretory pathway is regulated by host factors. Homeostatic STING trafficking via COPI-, COPII-, and clathrin-coated vesicles is important for maintaining baseline tissue and cellular immunity. Aberrant vesicular trafficking or lysosomal dysfunction produces an immune signal through STING, which often leads to tissue pathology in mice and humans. Many trafficking-mediated diseases of STING signaling appear to impact the central nervous system, leading to neurodegeneration. Therefore, STING trafficking introduces a new dimension of immune signaling that likely has broad implications in human disease.
A regularization method based on level-sets for the problem of crack detection from electrical measurements
Authors: De Cezaro A , Hafemann E , Leitão A , Osses A
Published: January 2023

We investigate regularization methods for solving the problem of crack detection in bounded planar domains from electrical measurements on the boundary. Based on the multiple level-set approach introduced in Álvarez et al (2009 J. Comput. Phys.
228 5710–21) and on the regularization strategy devised in De Cezaro et al (2009 Inverse Problems
25 035004), we propose a Tikhonov type method for stabilizing the inverse problem. Convergence and stability results for this Tikhonov method are proven. An iterative method of (multiple) level-set type is derived from the optimality conditions for the Tikhonov functional, and a relation between this method and the iterated Tikhonov method is established. The proposed level-set method is tested on the same benchmark problem considered in Álvarez et al (2009 J. Comput. Phys.
228 5710–21). The numerical experiments demonstrate its ability to identify cracks in different scenarios with high accuracy even in the presence of noise.
Ultralow voltage (1 μV) electrical switching of SnS thin films driven by a vertical electric field
Authors: Dragoman Mircea , Dragoman Daniela , Dinescu Adrian , Avram Andrei , Vulpe Silviu , Aldrigo Martino , Braniste Tudor , Suman Victor , Rusu Emil , Tiginyanu Ion
Published: January 2023

In this paper, we show in a series of experiments on 10 nm thick SnS thin film-based back-gate transistors that in the absence of the gate voltage, the drain current versus drain voltage (I
D–V
D) dependence is characterized by a weak drain current and by an ambipolar transport mechanism. When we apply a gate voltage as low as 1 μV, the current increases by several orders of magnitude and the I
D–V
D dependence changes drastically, with the SnS behaving as a p-type semiconductor. This happens because the current flows from the source (S) to the drain (D) electrode through a discontinuous superficial region of the SnS film when no gate voltage is applied. On the contrary, when minute gate voltages are applied, the vertical electric field applied to the multilayer SnS induces a change in the flow path of the charge carriers, involving the inner and continuous SnS layer in the electrical conduction. Moreover, we show that high gate voltages can tune significantly the SnS bandgap.
Dosimetric delivery validation of dynamically collimated pencil beam scanning proton therapy
Authors: Nelson Nicholas P , Culberson Wesley S , Hyer Daniel E , Geoghegan Theodore J , Patwardhan Kaustubh A , Smith Blake R , Flynn Ryan T , Yu Jen , Gutiérrez Alonso N , Hill Patrick M
Published: January 2023

Objective. Pencil beam scanning (PBS) proton therapy target dose conformity can be improved with energy layer-specific collimation. One such collimator is the dynamic collimation system (DCS), which consists of four nickel trimmer blades that intercept the scanning beam as it approaches the lateral extent of the target. While the dosimetric benefits of the DCS have been demonstrated through computational treatment planning studies, there has yet to be experimental verification of these benefits for composite multi-energy layer fields. The objective of this work is to dosimetrically characterize and experimentally validate the delivery of dynamically collimated proton therapy with the DCS equipped to a clinical PBS system. Approach. Optimized single field, uniform dose treatment plans for 3 × 3 × 3 cm3 target volumes were generated using Monte Carlo dose calculations with depths ranging from 5 to 15 cm, trimmer-to-surface distances ranging from 5 to 18.15 cm, with and without a 4 cm thick polyethylene range shifter. Treatment plans were then delivered to a water phantom using a prototype DCS and an IBA dedicated nozzle system and measured with a Zebra multilayer ionization chamber, a MatriXX PT ionization chamber array, and Gafchromic™ EBT3 film. Main results. For measurements made within the SOBPs, average 2D gamma pass rates exceeded 98.5% for the MatriXX PT and 96.5% for film at the 2%/2 mm criterion across all measured uncollimated and collimated plans, respectively. For verification of the penumbra width reduction with collimation, film agreed with Monte Carlo with differences within 0.3 mm on average compared to 0.9 mm for the MatriXX PT. Significance. We have experimentally verified the delivery of DCS-collimated fields using a clinical PBS system and commonly available dosimeters and have also identified potential weaknesses for dosimeters subject to steep dose gradients.
Low-loss, broadband MMI coupler based on thin film lithium niobate platform
Authors: Li Mengyuan , Rao Lan , He Xiaoying , Tian Feng , Pan Xiaolong , Xin Xiangjun
Published: January 2023

A low-loss broadband power splitter based on X-cut lithium niobate is proposed by utilizing the multimode interference coupler with a shallow-etched slot, wedge-shaped structure and SiO2 cladding. The multimode waveguide with a shallow-etch slot could reduce the sensitivity of multi-mode region on the wavelength and reach to high-quality imaging requirements. Results show that there is an excess loss around 0.01 dB at the operation wavelength of 1550 nm, a broad operation bandwidth of ∼ 1314 nm and large tolerance in the shallow-etching. Additionally, our proposed device has been compared with the published and conventional multimode interference coupler for presenting good low-loss and broad bandwidth.
Positron annihilation studies of methylammonium lead bromide perovskite
Authors: Moshat Sudipta , Ray Partha Pratim , Sil Sayantan , Dhar Joydeep , Sanyal Dirtha
Published: January 2023

Methylammonium lead halide-based perovskite has shown excellent optoelectronic properties. But their performances and stability are critically affected by the ionic defects present in the crystal lattice. In this article, we have investigated the presence of ionic vacancy mediated defects formation in ball mill ground methylammonium lead bromide (MAPbBr3) which has applications in tandem solar cell, light emitting diodes and laser devices. The evaluation of those point defects with temperature was analysed by employing the positron annihilation spectroscopic (PAS) studies. The phase transition from tetragonal to cubic phases around 260 K was exactly correlated with the temperature-dependent ‘S parameter’ determination from PAS analysis and with dc conductivity measurement. From coincidence Doppler broadening (CDB) spectroscopy significant proportion of defects arising from lead vacancy was observed whose magnitude reduces from the low-temperature tetragonal phase to higher temperature cubic phases.
Non-singular bouncing model in energy momentum squared gravity
Authors: Yousaf Z , Bhatti M Z , Aman H , Sahoo P K
Published: January 2023

This work is concerned to study the bouncing nature of the Universe for an isotropic configuration of fluid



α
β

and Friedmann-Lemaître-Robertson-Walker metric scheme. This work is carried out under the novel

f
(

,



α
β



α
β

)

gravitation by assuming a specific model i.e.

f
(

,



2

)

=


+
α



2

+

2
λ



2

with α and λ are constants, serving as free parameters. The terms



and



2

served as an Gauss-Bonnet invariant and square of the energy-momentum trace term as an inclusion in the gravitational action respectively, and is proportional to



2

=



α
β



α
β

. A specific functional form of the Hubble parameter is taken to provide the evolution of cosmographic parameters. A well known equation of state parameter,

ω
(
t
)
=
−

k
log
(
t
+
ϵ
)

t

−
1

is used to represent the dynamical behavior of energy density, matter pressure and energy conditions. A detailed graphical analysis is also provided to review the bounce. Furthermore, all free parameters are set in a way, to make the supposed Hubble parameter act as the bouncing solution and ensure the viability of energy conditions. Conclusively, all necessary conditions for a bouncing model are checked.
Estimation of laser light propagation in biological tissue during laser-tissue bonding using Monte Carlo simulation
Authors: Alam Zoya , Poddar Raju
Published: January 2023

Monte Carlo simulations are an elementary approach towards modeling light propagation in tissues. The detection of subsurface temperature in tissues during laser mediated therapies and microsurgeries is crucial for estimating associated thermal damage. MC simulation provides with the possibility to optimize the process. The approach has been used to model light propagation, associated energy deposition, and the temperature distribution inside the tissue. Understanding the extent of laser light transmittance and heat distribution within the tissue is crucial for minimizing damage to the adjacent biological tissues. The total photon weight absorbed estimates the total heat distribution within the volume. A three-layer heterogeneous tissue was specified consisting of only the epidermis, dermis, and the subcutaneous fat tissue. The hop, drop, and spin trail of photons depends on the optical properties of these layers. The energy deposition and temperature distribution estimation are obtained by the MC simulation method. A real-time measurement of the temperature profile was also performed. The experimental results were in close congruence with the simulation result. The simulation results show good reproducibility of the real temperature distribution. Monte Carlo method can, thereby, be used in estimation and optimization laser induced processes.
Evaluation and optimization of geometry parameters of GAGG scintillator-based Compton Camera for medical imaging by Monte Carlo simulation
Authors: Zarei H. , Razaghi S. , Nagao Y. , Itoh M. , Yamaguchi M. , Kawachi N. , Ay M.R. , Watabe H.
Published: January 2023

In nuclear medicine, the development of portable imaging
devices that provide high imaging resolution and sensitivity,
capable of imaging gamma rays with a wide energy range and multiple
radioisotopes tracing capabilities, is so important. These goals
have been possible thanks to developing a compact Compton camera, a
collimatorless detector coupled to compact silicon
photomultiplier(SiPM) array, using scintillator crystal. In this
study, the portable segmented GAGG:Ce scintillator-based Compton
camera (CC) is optimized with the GATE, a Monte Carlo simulation
toolkit based on Geant4, to maximize its performance for a wide
range of gamma-ray energy (364–1000 keV). The geometrical
parameters are selected as optimization parameters to investigate
their effects on CC's performance, including imaging resolution and
absolute detection efficiency (DE
a
). The geometry parameters of
CC include the planner area of scatterer and absorber detectors,
their thicknesses, and the distance between them. The results for
the energy range of 364–1000 keV show that the most important
contributions to the spatial resolution and DE
a
of the camera
are SAD (scatterer to absorber distance) and the scatterer area
while changing absorber area (AA
) showed the most negligible
impact. In the short SADs, imaging resolution and DE
a
are
significantly affected by the detector's size and thickness. On the
other hand, in the long SADs (> 4 cm), both spatial resolution and
DE
a
are significantly affected by the detector's area but less
affected by the detector's thickness. Decreasing the scatterer's
thickness and the absorber's size or thickness improves imaging
resolution without significantly reducing DE
a
. The simulation
study's findings presented here will provide valuable guidelines for
researchers choosing a desired CC's design according to particular
objectives, manufacturing limitations in scintillator growth, cost,
etc.
Simulation study for an in-situ calibration system for the measurement of the snow accumulation and the index-of-refraction profile for radio neutrino detectors
Authors: Beise J. , Glaser C.
Published: January 2023

Sensitivity to ultra-high-energy neutrinos (E > 17 eV) can
be obtained cost-efficiently by exploiting the Askaryan effect in
ice, where a particle cascade induced by the neutrino interaction
produces coherent radio emission that can be picked up by
antennas. As the near-surface ice properties change rapidly within
the upper 𝒪(100 m), a good understanding of the
ice properties is required to reconstruct the neutrino
properties. In particular, continuous monitoring of the snow
accumulation (which changes the depth of the antennas) and the
index-of-refraction n(z) profile are crucial for an accurate
determination of the neutrino's direction and energy. We present an
in-situ calibration system that extends the radio detector station
with two radio emitters to continuously monitor the firn properties
within the upper 40 m by measuring the time differences between
direct and reflected (off the surface) signals (D'n'R). We determine
the optimal positions of two transmitters at all three sites of
current and future in-ice radio detectors: Greenland, Moore's Bay,
and the South Pole. For the South Pole we find that the snow
accumulation Δh can be measured with a resolution of 3 mm
and the parameters of an exponential n(z) profile α and 
z
0 with 0.04% and 0.14% precision respectively, which
constitutes an improvement of more than a factor of 10 as compared
to the inference of the n(z) profile from density measurements.
Additionally, as this technique is based on the measurement of the
signal propagation times we are not bound to the conversion of
density to index-of-refraction. We quantify the impact of these ice
uncertainties on the reconstruction of the neutrino vertex,
direction, and energy and find that the calibration device measures
the ice properties to sufficient precision to have negligible
influence.
Potentially underestimated gas flaring activities—a new approach to detect combustion using machine learning and NASA’s Black Marble product suite
Authors: Chakraborty Srija , Oda Tomohiro , Kalb Virginia L , Wang Zhuosen , Román Miguel O
Published: January 2023

Monitoring changes in greenhouse gas (GHG) emission is critical for assessing climate mitigation efforts towards the Paris Agreement goal. A crucial aspect of science-based GHG monitoring is to provide objective information for quality assurance and uncertainty assessment of the reported emissions. Emission estimates from combustion events (gas flaring and biomass burning) are often calculated based on activity data (AD) from satellite observations, such as those detected from the visible infrared imaging radiometer suite (VIIRS) onboard the Suomi-NPP and NOAA-20 satellites. These estimates are often incorporated into carbon models for calculating emissions and removals. Consequently, errors and uncertainties associated with AD propagate into these models and impact emission estimates. Deriving uncertainty of AD is therefore crucial for transparency of emission estimates but remains a challenge due to the lack of evaluation data or alternate estimates. This work proposes a new approach using machine learning (ML) for combustion detection from NASA’s Black Marble product suite and explores the assessment of potential uncertainties through comparison with existing detections. We jointly characterize combustion using thermal and light emission signals, with the latter improving detection of probable weaker combustion with less distinct thermal signatures. Being methodologically independent, the differences in ML-derived estimates with existing approaches can indicate the potential uncertainties in detection. The approach was applied to detect gas flares over the Eagle Ford Shale, Texas. We analyzed the spatio-temporal variations in detections and found that approximately 79.04% and 72.14% of the light emission-based detections are missed by ML-derived detections from VIIRS thermal bands and existing datasets, respectively. This improvement in combustion detection and scope for uncertainty assessment is essential for comprehensive monitoring of resulting emissions and we discuss the steps for extending this globally.
A declining trend of methane emissions in the Los Angeles basin from 2015 to 2020
Authors: Yadav Vineet , Verhulst Kristal , Duren Riley , Thorpe Andrew , Kim Jooil , Keeling Ralph , Weiss Ray , Cusworth Dan , Mountain Marikate , Miller Charles , Whetstone James
Published: January 2023

The Los Angeles (LA) basin was responsible for approximately 20% of California’s methane emissions in 2016. Hence, curtailment of these emissions is required to meet California’s greenhouse gas emissions reduction targets. However, effective mitigation remains challenging in the presence of diverse methane sources like oil and gas production fields, refineries, landfills, wastewater treatment facilities, and natural gas infrastructure. In this study, we study the temporal variability in the surface concentrations from February 2015 to April 2022 to detect a declining trend in methane emissions. We quantify the reduction due to this declining trend through inverse modeling and show that methane emissions in the LA basin have declined by 15 Gg, or ∼7% over five years from January 2015 to May 2020.
Gaussian copula modeling of extreme cold and weak-wind events over Europe conditioned on winter weather regimes
Authors: Tedesco Paulina , Lenkoski Alex , Bloomfield Hannah C , Sillmann Jana
Published: January 2023

A transition to renewable energy is needed to mitigate climate change. In Europe, this transition has been led by wind energy, which is one of the fastest growing energy sources. However, energy demand and production are sensitive to meteorological conditions and atmospheric variability at multiple time scales. To accomplish the required balance between these two variables, critical conditions of high demand and low wind energy supply must be considered in the design of energy systems. We describe a methodology for modeling joint distributions of meteorological variables without making any assumptions about their marginal distributions. In this context, Gaussian copulas are used to model the correlated nature of cold and weak-wind events. The marginal distributions are modeled with logistic regressions defining two sets of binary variables as predictors: four large-scale weather regimes (WRs) and the months of the extended winter season. By applying this framework to ERA5 data, we can compute the joint probabilities of co-occurrence of cold and weak-wind events on a high-resolution grid

(

0.2
∘

)

.Our results show that (a) WRs must be considered when modeling cold and weak-wind events, (b) it is essential to account for the correlations between these events when modeling their joint distribution, (c) we need to analyze each month separately, and (d) the highest estimated number of days with compound events are associated with the negative phase of the North Atlantic Oscillation (3 days on average over Finland, Ireland, and Lithuania in January, and France and Luxembourg in February) and the Scandinavian blocking pattern (3 days on average over Ireland in January and Denmark in February). This information could be relevant for application in sub-seasonal to seasonal forecasts of such events.
A stationary model of non-intersecting directed polymers
Authors: Barraquand Guillaume , Doussal Pierre Le
Published: January 2023

We consider the partition function

Z

ℓ

(

x
⃗

,
0
|

y
⃗

,
t
)

of

ℓ

non-intersecting continuous directed polymers of length t in dimension

1
+
1

, in a white noise environment, starting from positions

x
⃗

and terminating at positions

y
⃗

. When

ℓ
=
1

, it is well known that for fixed x, the field

log

Z
1

(
x
,
0
|
y
,
t
)

solves the Kardar–Parisi–Zhang equation and admits the Brownian motion as a stationary measure. In particular, as t goes to infinity,

Z
1

(
x
,
0
|
y
,
t
)

/

Z
1

(
x
,
0
|
0
,
t
)

converges to the exponential of a Brownian motion B(y). In this article, we show an analogue of this result for any

ℓ

. We show that

Z

ℓ

(

x
⃗

,
0
|

y
⃗

,
t
)

/

Z

ℓ

(

x
⃗

,
0
|

0
⃗

,
t
)

converges as t goes to infinity to an explicit functional

Z

ℓ

s
t
a
t

(

y
⃗

)

of

ℓ

independent Brownian motions. This functional

Z

ℓ

s
t
a
t

(

y
⃗

)

admits a simple description as the partition sum for

ℓ

non-intersecting semi-discrete polymers on

ℓ

lines. We discuss applications to the endpoints and midpoints distribution for long non-crossing polymers and derive explicit formula in the case of two polymers. To obtain these results, we show that the stationary measure of the O’Connell–Warren multilayer stochastic heat equation is given by a collection of independent Brownian motions. This in turn is shown via analogous results in a discrete setup for the so-called log-gamma polymer and exploit the connection between non-intersecting log-gamma polymers and the geometric Robinson–Schensted–Knuth correspondence found in Corwin-O’Connell-Seppäläinen-Zygouras (2014 Duke Math. J.
163 513–63).