bluuebunny/crossref_metadata_2025 huggingface dataset:
Differential Effects of Type, Route and Dose of Menopausal Hormone Therapy on survival, cancer, cardiovascular and dementia risks in 10 million women age over 65: a retrospective case-control study
Authors: Baik Seo , Baye Fitsum , McDonald Clement
Published: March 2023

Objectives: To examine the variation in patient’s health
outcomes across different type, route, and strength of menopausal
hormone therapy (HT). Design: Retrospective case-control study
Setting: United States 2007-2020 Population: 10
million women aged 65 or more in US Medicare. Methods: Cox
regression models with time-varying type, route, and strength of HT as
well as patient characteristics. Main Outcome(s): all-cause
mortality; 5 cancers- breast, lung, endometrial, colorectal, ovarian
cancers; 6 CV conditions- ischemic heart diseases, heart failure, venous
thromboembolism, stroke, atrial fibrillation, acute myocardial
infarction; and dementia. Results Estrogen monotherapy (ET)
exhibited a significant, 19% (HR=0.81; 95% CI 0.79-0.82), relative
risk reduction on mortality. The reduction was greater with estradiol
and vaginal/transdermal than conjugated estrogen and oral preparations.
ET also exhibited significant risk reductions for all study
cancers; breast (15%), lung (13%), endometrial (29%), colorectal
(13%) and ovarian (14%). All ET preparations except low-dose slightly
increased risk of ischemic heart diseases (1-4%). Both combination
therapy and progestogen monotherapy exhibited significantly
increased risk of breast cancer (7-14%). Oral ET exhibited
moderately increased risk of stroke (6%) and dementia (2%).
Conclusions: Among senior Medicare women, the effect of
menopausal HT varies by type, route, and strength. The use of estradiol,
vaginal/transdermal, and low/medium for menopausal care is safer than
its counterparts.
Nucleus accumbens shell lesions alleviate symptoms in kainic acid-induced epileptic rats
Authors: xue shuaishuai
Published: March 2023

Epilepsy is a recurrent neurological disease caused by hypersynchronous
firing of neurons in the brain. Neuronal apoptosis, microgliosis, or
astrogliosis in hippocampus are considered to be important features of
temporal lobe epilepsy. As an important part of the ventral striatum,
the nucleus accumbens is closely connected to the hippocampus. As the
findings of the reviewed articles indicated, the nuleus accumbens is
divided into the shell and the core. The nucleus accumbens shell is a
relevant brain region to process reward-related and motivated
behaviours, emotional process and social information. Nucleus accumbens
shell has a good application effect in the field of drug addiction and
mania. Our previous studies have shown that the nucleus accumbens shows
abnormal excitation after seizures. In our previous experiments, the
number of seizures decreased when this excitation was disrupted.
However, the mechanisms of action of Nucleus accumbens shell lesions
remain unclear. In this paper, we explored the hippocampal changes
inhibited by nucleus accumbens lesions on the basis of the kainic acid
animal model of epilepsy. We explored the anti-epileptic effect and
mechanism of action of electrical lesions in nucleus accumbens, and
found that the mechanism may be to reduce the toxic effects caused by
the proliferation of astrocytes and microglia in the hippocampus. It can
also inhibit the reduction of neurons and thus play a role in
controlling seizures. These results suggest that the nucleus accumbens
plays an important role in inhibiting seizures.
Uncertain spatial pattern of future land use and land cover change and its impacts on terrestrial carbon cycle over the Arctic-Boreal region of North America
Authors: Luo Meng , Li Fa , Hao Dalei , Zhu Qing , Dashti Hamid , Chen Min
Published: March 2023

Land use and land cover change (LULCC) represents a key process of
human-Earth system interaction and has profound impacts on ecosystem
carbon cycling. As a key input for ecosystem models, future gridded
LULCC data is typically spatially downscaled from regionally LULCC
projections by integrated assessment models. The uncertainty associated
with different spatial downscaling methods and its impacts on subsequent
model projections have been historically ignored and rarely examined.
This study investigated this problem using two representative spatial
downscaling methods and focused on the impacts on the carbon cycle over
ABoVE domain. Specifically, we used the Future Land Use Simulation model
(FLUS) and Demeter model to generate 0.25-degree gridded LULCC data with
the same input of regional LULCC projections from Global Change Analysis
Model, under SSP126 and SSP585. The two sets of downscaled LULCC were
used to drive CLM5 to prognostically simulate terrestrial carbon cycle
dynamics over the 21st century. The results suggest large
spatial-temporal differences between two LULCC datasets under both
SSP126 and SSP585. The LULCC differences further lead to large
discrepancies in the spatial patterns of projected carbon cycle
variables, which are more than 79% of the contributions of LULCC in
2100. Besides, the difference for LULCC and carbon flux under SSP126 is
generally larger than those under SSP585. This study highlights the
importance of considering the uncertainties induced by spatial
downscaling process in future LULCC projections and carbon cycle
simulations.
Monitoring Shelf Sea Dynamics with Ocean-Bottom Distributed Acoustic Sensing
Authors: Viens Loïc , Spica Zack Jack , Delbridge Brent G. , Arbic Brian K.
Published: March 2023

The mixing of ocean waters on continental shelves, which is mainly
driven by waves, tides, and currents, plays a key role in the physics,
biogeochemistry, and ecology of coastal regions. This study focuses on
four months of continuous data recorded along a telecommunication cable
offshore Oregon, USA, with Distributed Acoustic Sensing (DAS). We apply
a cross-correlation approach to the continuous DAS data to infer the
propagation of ocean surface gravity waves in the 3 to 100 s period
range and estimate near-surface ocean flows. We observe strong
spatio-temporal variations of ocean flows along the cable over four
months, with strong impacts from a series of storms in late October
2021. We find that our measurements capture oceanic surface motions as
those measured by nearby traditional oceanographic instruments. This
study demonstrates that ocean-bottom DAS can be used to infer the
dynamic properties of near-shore oceans with an unprecedented
spatio-temporal resolution.
Generating functions of binary products of (p,q)-Fibonacci-like numbers with odd and even certain numbers and polynomials
Authors: Saba Nabiha , Boussayoud Ali
Published: March 2023

In this paper, we study the symmetric and the generating functions for odd and even terms of the second-order linear recurrence sequences. we introduce a operator in order to derive a new family of generating functions of odd and even terms of Mersenne numbers, Mersenne Lucas numbers, (p,q)- Fibonacci-like numbers, k-Pell polynomials and k-Pell Lucas polynomials. By making use of the operator defined in this paper, we give some new generating functions of the products of (p,q)-Fibonacci-like numbers with odd and even terms of certain numbers and polynomials.
Variations of star selection principles on small spaces
Authors: Casas-De la , Garcia-Balan Sergio
Published: March 2023

In this work, we introduce the notions of Star-?K and absolutely Star-?K
spaces which allow us to unify results among several properties in the
theory of star selection principles on small spaces. In particular, results
on star selective versions of the Menger, Hurewicz and Rothberger properties
and selective versions of property (a) regarding the size of the space.
Connections to other well-known star properties are mentioned. Furthermore,
the absolute and selective version of the neighbourhood star selection
principle are introduced. As an application, it is obtained that the extent
of a separable absolutely strongly star-Menger (absolutely strongly
star-Hurewicz) space is at most the dominating number d (the bounding number
b).
N-isoclinic Lie crossed modules
Authors: Çağlayan Elif
Published: March 2023

We define the notion of n-isoclinic Lie crossed modules and give the relation
between the n-isoclinic Lie crossed modules and n-isoclinic Lie algebras.
Post-Traumatic Stress Disorder; What is Behind the Invisible Wounds??!!!
Authors: Zaky Eman Ahmed
Published: March 2023

Post-traumatic stress disorder (PTSD) is the mental disorder that is encountered in sufferers who experienced or witnessed any kind of distressing events involving life threatening situations or extreme physical harm. Unfortunately, such a disorder significantly hurts the spirit, soul, mind, emotions, memories, and physiological body functions. It is a complicated condition that can be under-reported, missed, or undiagnosed, accordingly, raising public awareness about its etiology, manifestations, and prompt ways to deal with is crucial for its early diagnosis and proper intervention that will improve the quality of life of its sufferers dramatically. As not all wounds are visible and those invisible wounds are very difficult to treat and unlikely to disappear, it is important to collaborate efforts to understand and respect the suffering of PTSD victims and support them to bypass such a drastic disorder.
Assistive technology access in longitudinal datasets: a global review
Authors: Danemayer Jamie , Mitra Sophie , Holloway Cathy , Hussein Shereen
Published: March 2023

Functional limitations become more prevalent as populations age, emphasising an increasingly urgent need for assistive technology (AT). Critical to meeting this need trajectory is understanding AT access in older ages. Yet few publications examine this from a longitudinal perspective.
This review aims to identify and collate what data exist globally, seeking all population-based cohorts and repeated cross-sectional surveys through the Maelstrom Research Catalogue (searched May 10, 2022) and the Disability Data Report (published 2022), respectively. Datasets incorporating functional limitations modules and question(s) dedicated to AT, with a wave of data collection since 2009, were included.
Of 81 cohorts and 202 surveys identified, 47 and 62 meet inclusion criteria, respectively. Over 40% of cohorts were drawn from high-income countries which have already experienced significant population ageing. Cohorts often exclude participants based on pre-existing support needs. For surveys, Africa is the most represented region (40%). Globally, 73% of waves were conducted since 2016. 'Use' is the most collected AT access indicator (69% of cohorts and 85% of surveys). Glasses (78%) and hearing aids (77%) are the most represented AT. While gaps in data coverage and representation are significant, collating existing datasets highlights current opportunities for analyses and methods for improving data collection across the sector.
Revivalist: Medical Herbs and Rejuvenation in the Works of Lady Augusta Gregory
Authors:   University College Cork, Walker-Dunseith Holly May
Published: March 2023

When Lady Augusta Gregory (1852-1932) effected her famous mid-life self-reinvention from Anglo-Irish landlady to revivalist dramatist, healing women from her locality provided significant guides and models for her new life and work. This article will discuss what Gregory learned from the lore of a local healer, the shadowy Bridget Ruane (who died c.1899). It will analyse how Gregory worked Ruane’s folk medical knowledge into her prose writings and plays, including The Pot of Broth (1904). In restoring the name of this non-elite woman from the west of Ireland, this article suggests the benefits of casting the net more widely for names to stand alongside Gregory’s as creators of Revival-era culture.
“Not So Glamorous at All”: The Consequences of Fame and Celebrity Status in The Cranberries’ To The Faithful Departed
Authors: Baró Casanovas Josep
Published: March 2023

The Cranberries have been considered to be one of the major rock bands from Ireland. From 1993 until 2019, they released eight studio albums, and hit the world charts with songs such as “Linger” and “Zombie”, before disbanding following singer Dolores O’Riordan’s death. After two very successful and critically acclaimed records, The Cranberries’ third release To The Faithful Departed (1996) became the target of harsh criticism, as the press considered it to be lyrically shallow. As a result, The Cranberries’ third album has been traditionally analysed in that way. This paper aims at providing a new, comprehensive analysis of The Cranberries’ To The Faithful Departed by bringing the band’s then recently achieved stardom into focus, as such an experience had a significant impact on the four members’ emotional state, and hence in the songwriting. Thus, it is hoped that the present article will provide a greater understanding of how the lyrics of The Cranberries’ 1996 album reflect the struggles of a band achieving celebrity status in the music industry. This essay can be viewed as innovative for two reasons: firstly, there has been a lack of academic research on The Cranberries, and secondly, it offers a new reading of their third record To The Faithful Departed.
Derek Mahon’s Anti-capitalist Ecologies
Authors: O'Rourke Ciarán
Published: March 2023

Literary critics have generally cast Derek Mahon as a humanist in dialogue with existentialist themes, or as a poet of exile, while highlighting the qualities of irony and skepticism that permeate his work. This paper is receptive to such readings, but proposes an alternative emphasis, situating Mahon as an anti-capitalist writer, his poetic ventures often serving to critique and counteract what he called “the bedlam of acquisitive force / That rules us, and would rule the universe” (2018a: 59). This discussion surveys Mahon’s long-standing respect for a variety of anti-capitalist poets and thinkers, from Brecht and Pasolini to Naomi Klein; sheds light on his penetrating investigations of warfare and ecological despoliation as offshoots of imperial and capitalist expansion; and explores his advocacy of poetry as a corrective to what he viewed as the glib commercialism and intellectual complacencies accompanying market-driven globalization, or in his words, “the explosive growth of high finance / directing thought” (2020h: 67). Over the course of this paper, my objective is to present a “new” Mahon: a poet whose self-described “left-wingery” informed, and found expression in, his work and practice (2017d: 82).
International Tourism Policy and Development: Indian Tourism Policy
Authors: Mehrad Dr. Aida , Sharma Kaushal , Patil Rishab Madan , Wilson Wilfin Mangalan , Mehrad Aida
Published: March 2023

India is one of the worldwide tourist goals. The current study focused on it in the context of tourism policy and its industry, which is rapidly growing, particularly in Delhi and Mumbai. The rapid growth of India's tourism industry is affected by several factors, including the country's high economic growth rate over the past decade and the fact that it is now one of the more affordable destinations for foreign tourists. Additionally, several significant challenges are associated with developing the Indian tourism industry. To address these challenges and ensure that India's tourism industry continues to increase in the years to come, the government has introduced several new tourism policies aimed at improving the infrastructure available in the country and making it easier for tourists to come and visit. These policies include introducing a dedicated high-speed rail link between Delhi and Mumbai, developing a new visa policy for foreign visitors, and simplifying the process for acquiring permits for filming or photography in popular tourist attractions nationwide. Overall, these policies represent a significant step in developing the Indian tourism industry and will go a long way towards guaranteeing that the country remains a popular destination for tourists worldwide for many years; this study focused on it deeply based on earlier investigations.
Methane Emission and Metabolic Status in Peak Lactating Dairy Cows and Their Assessment Via Methane Concentration Profile
Authors: Bošnjaković Dušan , Kirovski Danijela , Prodanović Radiša , Vujanac Ivan , Arsić Sveta , Stojković Milica , Dražić Slavica , Nedić Sreten , Jovanović Ljubomir
Published: March 2023

Ruminant husbandry contributes to global methane (CH4) emissions and beside its negative impact on the environment, enteric CH4 emissions cause a loss of gross energy intake in cows. The study is aimed to estimate CH4 emission and metabolic status in dairy cows via the methane concentration profile as a tool for analyzing the CH4 production pattern. The study included eighteen cows whose enteric CH4 emission was measured during three consecutive days in three periods: 2 hours before (P1), 2–4 hours (P2) and 6–8 hours (P3) after the morning feeding. Based on CH4 enteric emissions, cows were divided into two groups (n=6, respectively): HM (average CH4 concentration: 5430.08 ± 365.92 ppm) and LM (average CH4 concentration: 1351.85 ± 205.20 ppm). Following CH4 measurement, on day 3, venous blood was sampled to determine the indicators of the metabolic status. HM cows had significantly higher average CH4 concentrations, maximum and average CH4 peak amplitude than LM cows in all measuring periods (P1-P3), while the number of CH4 peaks tended to be higher in HM than in LM cows in P2. There were no differences in the maximum and average CH4 peak width and average distance among two CH4 peaks between examined groups of cows. HM cows had significantly higher total protein concentrations and significantly lower total bilirubin and NEFA concentrations than LM cows. In conclusion, HM cows have a greater number of eructations and release more CH4 per eructation than LM cows, hence the differences in metabolic status are most likely related to the differences in their liver function.
A Statistical Comparison of Call Volume Uniformity Due to Mailing Strategy
Authors: Raim Andrew M. , Nichols Elizabeth , Mathew Thomas
Published: March 2023

For operations such as a decennial census, the U.S. Census Bureau sends mail to potential respondents inviting a self-response. It is suspected that the mailing strategy affects the distribution of call volumes to the U.S. Census Bureau's telephone helplines. For staffing purposes, more uniform call volumes throughout the week are desirable. In this work, we formulate tests and confidence intervals to compare uniformity of call volumes resulting from competing mailing strategies. Regarding the data as multinomial observations, we compare pairs of call volume observations to determine whether one mailing strategy has multinomial cell probabilities closer to the uniform probability vector compared to another strategy. A motivating illustration is provided by call volume data recorded in three studies which were carried out in advance of the 2020 Decennial Census.
Generation of profit and loss statements by Syrian companies in the context of hyperinflation
Authors: KULIKOVA Lidiya I. , ALSAFADI Ammar
Published: March 2023

Subject. This article deals with the issues related to the preparation of the Profit and Loss Statement by companies of the Syrian Arab Republic, taking into account consumer price indices in the context of hyperinflation, based on the provisions of IAS 29 – Financial Reporting in Hyperinflationary Economies.
Objectives. The article aims to identify and find a solution to the problems of generating the Profit and Loss Statement, as well as develop appropriate methodological recommendations.
Methods. For the study, we used observation, comparison, grouping, classification, generalization, and interpretation. Scientific works and publications of scientists on the theory of inflation and hyperinflation, the Central Bureau of Statistics (Syria) (CBS) data on consumer price indices, provisions of IAS 29 on the formation of reporting by organizations whose functional currency is the currency of the hyperinflationary economy, are the methodological basis of the study.
Results. The article presents a test of the methodology for compiling the Profit and Loss Statement taking into account the recommendations of IAS 29 and shows the process of reporting using the materials of the Syrian Al-Ahlia Vegetable Oil Company. It also reads about the impact of hyperinflation on the items of the company's Profit and Loss Statement and its financial results, and compares the reporting data with indicators calculated on the basis of historical information. The article confirms the hypothesis that it is necessary to form a Profit and Loss Statement on the basis of the provisions of IAS 29 in the event of high inflation.
Conclusions. In the context of hyperinflation, financial statements based on historical cost are unreliable, mislead users, and cause difficulties in making management decisions. A positive financial result determined through the historical cost principle, is a fictitious profit.
Choosing an internal control model for agrarian organizations to ensure economic security
Authors: SAFONOVA Margarita F.
Published: March 2023

Subject. This article deals with the issues of achieving economic security of the agrarian market subjects in the context of digitalization of business through the organization of an effectively functioning system of internal control.
Objectives. The article aims to determine an effective model of internal control for medium-sized and large businesses in the agricultural sector of the economy, taking into account the general digitalization of the organization's business processes.
Methods. For the study, I used case and chronological analyses, computational and graphic methods, and analytical research methods.
Results. The article finds that at present, in the process of transformation, the COSO ERM Integrated Framework is a priority for building an internal control system, since its provisions are the most complete and exclude the narrow focus common to other models.
Conclusions and Relevance. An end-to-end risk-oriented system of internal control, based on international requirements, the experience of Russian organizations, permeating all structural units and based on digital technologies, implemented in the organizations of the agrarian market, will ensure economic security for the economic entity, the region, and the State as a whole. The results of the study can be used in the theory and practice of internal control, as well as for further scientific developments and practical application.
Reliability of reporting information from the standpoint of Yaroslav Sokolov's Accounting Paradox Theory
Authors: MERZLYAKOVA Ekaterina S.
Published: March 2023

Subject. This article considers the reliability of reporting information as one of the most important qualitative characteristics that ensure the usefulness of accounting data to interested users to make management decisions.
Objectives. The article aims to articulate an issue of the implemented methodology of research in the field of accounting, aimed at improving the reliability of accounting data.
Methods. For the study, I used the methods of analysis, systematization, comparison, and logical generalization.
Results. The article presents various definitions of the category of Fairness of Accounting Statements. It finds that compliance with the statutory regulations determines the boundaries of the accounting methodology. However, the statements do not reflect all the accounting events of the enterprise, and what is reflected is not always recorded correctly. In this regard, the perception of reporting data and the interpretation of the results of analysis by users may differ from the meaning implicit in the data, determined by the implemented accounting methodology. This kind of discrepancy between the content of accounting statements, determined by the accounting methodology, and the perception of these data by users can cause a situation that was defined by Russian academic economist, professor Yaroslav V. Sokolov (1938–2010) as the Paradox of Accounting. Quite a number of research papers are devoted to this problem, but most of them are not verified in practice.
Conclusions and Relevance. The article concludes that the financial statements, in reality, cannot be reliable, since they are just a simplified model of the financial and operating activities of the enterprise. The results obtained can be considered as a determination of the directions of further research in the field of the Accounting Paradox Theory by Yaroslav V. Sokolov.
Information security as an element of the economic security system of a business entity
Authors: PRONYAEVA Lyudmila I. , FEDOTENKOVA Ol'ga A. , PAVLOVA Anna V.
Published: March 2023

Subject. We consider organizational and methodological aspects for the formation of information security of an economic entity.
Objectives. The study aims to develop a theoretical and methodological approach to the formation of information security system of an economic entity, capable of ensuring the security of functional information systems and confidentiality of information through counteraction against various risks and threats.
Methods. We employ methods of scientific abstraction, formal logic.
Results. The paper characterizes modern software products that are used to ensure information confidentiality and prevent unauthorized access to it, identifies situations, in which threats to information security may arise.
Conclusions. The findings can be used by heads of organizations and relevant structural units in the implementation of policies to counter information threats.
Corporate reporting: A balance between sanction threats and corporate PR
Authors: ZAINULLIN Sergei B. , ZAINULLINA Ol'ga A.
Published: March 2023

Subject. This article discusses the change in approaches to the preparation of corporate reporting in the context of sanctions.
Objectives. The article aims to analyze changes in the information policy of Russian corporations.
Methods. For the study, we used a comparative analysis.
Results. Based on the analysis of the results of the anti-Russian sanctions, the article finds that they are forcing corporations to maintain a balance between the concealment of private information about shareholders and top managers and the need to conduct an information policy aimed at attracting investors.
Conclusions. Currently, the main efforts of the Russian corporate sector pursue the objective to protect shareholders and members of governance bodies from sanctions threats.
Spectral indicators of economic risk
Authors: MATVEEV Boris A.
Published: March 2023

Subject. The article addresses issues of efficient risk management and regulation of economic process as a whole.
Objectives. The purpose of this work is to improve the methodology and methods for measuring economic risk, increase the reliability and accuracy of its assessment, solve the problem of risk measurement with limited statistical information and unknown law of distribution of the studied economic value.
Methods. The study employs the apparatus of the spectral theory of random processes.
Results. I developed spectral indicators enabling to measure risk in real time, assess possible deviations of the economic value from the expected value and the quality of the economic process model. The spectral analysis made it possible to move from the study of the statistical model of economic risk to the study of its image in the integral Fourier transform. The spectral approach to risk assessment is verified on the innovation project case.
Conclusions. Spectral risk indicators take into account the dynamics of the economic process. They do not require an expert assessment of the probability and knowledge of the law of distribution of the risk-related economic value. They also enable improved accuracy of risk measurement.
Foreign economic and trade relations of the CIS countries in the context of the transformation of integration processes worldwide
Authors: MALAKHOVA Tat'yana S.
Published: March 2023

Subject. This article discusses the strengthening of political and economic ties between the countries of the Commonwealth of Independent States (CIS).
Objectives. The article aims to analyze some selected national measures by CIS country, identify the strengths and weaknesses of the economic cooperation between the CIS countries, and assess their positions in the context of the formation of a multipolar system.
Methods. For the study, I used the historical and logical, and scientific abstraction methods.
Results. The article presents the results of analysis of the key economic indicators of the CIS countries and states that the structure of industrial products by type of economic activity differs between partner countries significantly.
Conclusions. The article concludes that in the context of tightening the sanctions regime, it is necessary to strengthen cooperation ties between the economic entities of the CIS countries.
Design Exploration of Transonic Airfoils for Natural and Hybrid Laminar Flow Control Applications
Authors: Sudhi Anand , Radespiel Rolf , Badrya Camli
Published: March 2023

Designing transonic laminar swept wing at high Reynolds numbers is challenging due to the premature flow transition from the prominent crossflow instabilities (CFIs). Hence, natural laminar flow (NLF) wings are limited to lower sweep angles. In this study, hybrid laminar flow control (HLFC) is used to extend this limit to design low-drag transonic infinite wing. A multi-objective genetic algorithm with competing drag components as objectives is used to design NLF and HLFC airfoils. Optimal design is a tradeoff between the drag reduction from skin friction drag, pressure drag, and suction drag, and does not resemble initial airfoils. Airfoil shape and suction distribution are coupled and optimized simultaneously. Euler flow solver with integral boundary-layer method is coupled with a higher-fidelity Linear Stability Analysis using 2.5D approximation for transition prediction. At wing sweep of 22.5°, Mach number of 0.78, and Reynolds number of 30 million, optimum NLF airfoil has 27% lower drag than an optimum turbulent airfoil. The optimum HLFC airfoil showed a 25% lower total drag than the NLF airfoil. A higher optimum sweep angle was observed for low-drag HLFC airfoil (20.5°) in comparison to the NLF airfoil (16.8°) and both favored an undercut on the lower surface to dampen CFI.
Duality-Based Near-Fuel-Optimal Impulsive Trajectory Computation for Spacecraft Rendezvous Under Perturbations
Authors: Kim Youngkwang , Park Sang-Young , Kim Pureum
Published: March 2023

In this study, a novel impulsive trajectory optimization algorithm for near-fuel-optimal rendezvous under perturbations is presented. The algorithm, called algorithm for impulsive rendezvous trajectory optimization under perturbations (AIRTOP), is designed such that the accuracy of rendezvous constraints is improved as much as possible while retaining the first-order optimality, under high-fidelity dynamics models that encompass various orbital perturbations (e.g., nonspherical gravity, air drag, luni-solar gravity, and solar radiation pressure). To eliminate rendezvous constraint errors, AIRTOP solves the linearized impulsive rendezvous problem recursively using the nonsingular dual-primal optimization algorithm. To improve the computational efficiency, AIRTOP applies the approximate analytical gradient of the constraint error norm during its error elimination process. We present three numerical simulations near circular and elliptical orbits. The simulation results show that i) AIRTOP can successfully solve impulsive rendezvous problems under realistic orbital perturbations with minimal user intervention, and ii) it can generate more fuel-efficient solutions in similar or shorter computation time than two other methods, namely, the differential corrector of the General Mission Analysis Tool and the global optimization approach, which can also take complex perturbations into account.
Multifidelity Prediction Framework with Convolutional Neural Networks Using High-Dimensional Data
Authors: Emre Tekaslan Huseyin , Nikbay Melike
Published: March 2023

This paper proposes two novel multifidelity neural network architectures developed for high-dimensional inputs such as computational flowfields. We employed a two-dimensional flow-varying transonic supercritical airfoil problem while exploring and comparing our methods with the former “multifidelity deep neural networks” from the literature. We call these novel methods “modified multifidelity deep neural networks” and “multifidelity convolutional neural networks.” The main objective of this study is to establish an advanced multifidelity prediction framework that can be applied to any computational data; however, here, we applied our methods to the prediction of aerodynamic coefficients using pressure coefficient fields around the airfoil. To generate the dataset, first, a coarse grid is employed using the SU2 Euler solver for low-fidelity data; then, a relatively finer grid is used to obtain the viscous solutions by using the Spalart–Allmaras turbulence model for the high-fidelity data. The performance metrics to compare the methods are determined as the test accuracy, the physical training time, and the size of the high-fidelity samples. The results demonstrate that the proposed multifidelity neural network architectures outperform the multifidelity deep neural networks in predictive modeling using high-dimensional inputs by improving the multifidelity prediction accuracy significantly.
Resilient Autonomous Mission Management for Decentralized Multispacecraft Missions
Authors: Gillette Antony , George Alan
Published: March 2023

Autonomy will play a crucial role in achieving complex mission goals and reducing the burden for ground operations for upcoming ambitious aerospace missions. Standalone spacecraft can leverage autonomy concepts to optimize data collection and ensure robust operation. Autonomy can additionally provide a feasible method of ensuring coordination for spacecraft clusters through onboard peer-to-peer scheduling. The core of this framework, the schedule manager (SM), manages tasks by associating constraints with each task including time windows, task priority, conflict categories, and resource requirements, which assures that tasks will only run when capable. This increased control over individual tasks also improves the modularity of the overall mission plan and provides a built-in fail-safe in the event of unexpected task failure through the loading of predefined contingency schedules. Various other capabilities were added to the SM, including the SM data server to simplify commanding, distributed coordination, and integration with NASA Goddard Space Flight Center’s core Flight System (cFS) platform. Software validation was achieved with cFS unit tests, functional tests, and code analysis tools. Demonstrations were tested with a cluster of development boards in the loop as representative flight hardware.
Numerical Investigations of Laminar Separation Bubbles Under the Influence of Periodic Gusts
Authors: Ohno Duncan , Greiner Michael , Müller Jens , Rist Ulrich
Published: March 2023

Direct numerical simulations were performed to investigate the behavior of laminar separation bubbles subject to vertical gusts in an airfoil flow. Oscillating boundary-layer flows containing gusts—including unsteady pressure gradients—were prescribed via boundary conditions as well as forcing terms on a domain located in the upper rear section of a natural laminar flow airfoil. For this hybrid approach, unsteady Reynolds-averaged Navier-Stokes (URANS) simulations of the entire flowfield were carried out in conjunction with the so-called disturbance velocity approach, providing transient boundary conditions for the direct numerical simulation. A steady-state reference case with a Reynolds number of [Formula: see text] is compared and validated with results from wind tunnel experiments. Results of simulations at four different gust frequencies [Formula: see text] at the same amplitude [Formula: see text], each with and without additional disturbances to the boundary layer introducing oblique resonance, are presented and discussed in this paper. The time-dependent behavior of convective instability modes is evaluated by using the continuous wavelet transform and linear stability theory with an unsteady extension. Furthermore, the contribution of the absolute instability—which appears to be larger in the case of oscillating flow compared to the steady-state case—is discussed. Lock-in effects are identified at high gust frequencies.
Excimer Energies
Authors: Zhao Ruoqi , Hettich Christian , Zhang Jun , Liu Meiyi , Gao Jiali
Published: March 2023

A multistate energy decomposition analysis (MS-EDA) method is introduced for excimers using density functional theory. Although EDA has been widely applied to intermolecular interactions in the ground-state, few methods are currently available for excited state complexes. Here, the total energy of an excimer state is separated into exciton excitation energy ΔE_Ex (|Ψ_X•Ψ_Y >^*), resulting from the state interaction between locally excited monomer states |Ψ_X^*•Ψ_Y> and |Ψ_X•Ψ_Y^*>, a super-exchange resonance energy ΔE_SE, originating from the mutual charge transfer between two monomers |Ψ_X^+•Ψ_Y^-> and |Ψ_X^-•Ψ_Y^+>, and an orbital-and-configuration delocalization term ΔE_OCD due to the expansion of configuration space and block-localized orbitals to the fully delocalized dimer system. Although there is no net charge transfer in symmetric excimer cases, the resonance of charge-transfer states is critical to stabilizing the excimer. The monomer localized excited and charge-transfer states are variationally optimized, forming a minimal active space for nonorthogonal state interaction (NOSI) calculations in multistate density functional theory to yield the intermediate states for energy analysis. The present MS-EDA method focuses on properties unique to excited states, providing insights into exciton coupling, super-exchange and delocalization energies. MS-EDA is illustrated on the acetone and pentacene excimer systems; three configurations of the latter case are examined, including the optimized excimer, a stacked configuration of two pentacene molecules and the fishbone orientation. It is found that excited-state energy splitting is strongly dependent on the relative energies of the monomer excited states and the phase-matching of the monomer wave functions.
Influence of temperature on the performance of carbon- and ATO-supported OER catalysts in a GDE setup
Authors: Bornet Aline , Pittkowski Rebecca , Nielsen Tobias , Berner Etienne , Schroeder Johanna , Quinson Jonathan , Jensen Kirsten , Arenz Matthias
Published: March 2023

State-of-the-art industrial electrocatalysts for the oxygen evolution reaction (OER) under acidic conditions are Ir-based. Considering the scarce supply of Ir, it is imperative to use the precious metal as efficiently as possible. In this work, we immobilized ultrasmall Ir and Ir0.4Ru0.6 nanoparticles on two different supports to maximize their dispersion. One high surface area carbon support serves as reference but has limited technological relevance due to its lack of stability. The other support, antimony-doped tin oxide (ATO), has been proposed in the literature as a possible better support for OER catalysts. Temperature-dependent measurements performed in a newly developed gas diffusion electrode (GDE) setup reveal that surprisingly the catalysts immobilized on commercial ATO performed worse than their carbon-immobilized counterparts. The measurements suggest that the ATO support deteriorates particularly fast at elevated temperatures.
Automatic Screen-out of Ir(III) Complex Emitters by Combined Machine Learning and Computational Analysis
Authors: Cheng Zheng , Liu Jiapeng , Jiang Tong , Chen Mohan , Dai Fuzhi , Gao Zhifeng , Ke Guolin , Zhao Zifeng , Ou Qi
Published: March 2023

Organic light-emitting diodes (OLEDs) have gained widespread commercial use, yet there is a continuous need to identify innovative emitters that offer higher efficiency and broader color gamut. To effectively screen out promising OLED molecules that are yet to be synthesized, we perform a representation learning aided high throughput virtual screening (HTVS) over millions of Ir(III) complexes, a prototypical type of phosphorescent OLED material, constructed via a random combination of 278 reported ligands. We successfully screen out a decent amount of promising candidates for both display and lighting purposes, which are worth further experimental investigation. The high efficiency and accuracy of our model are largely attributed to the pioneering attempt of using representation learning to organic luminescent molecules, which is initiated by a pre-training procedure with over 1.6 million 3D molecular structures and frontier orbital energies predicted via semi-empirical methods, followed by a fine-tune scheme via the quantum mechanical computed properties over around 1500 candidates. Such workflow enables an effective model construction process that is otherwise hindered by the scarcity of labeled data, and can be straightforwardly extended to the discovery of other novel materials.
Ocean Surface Gravity Wave Excitation of Flexural Gravity and Extensional Lamb Waves in Ice Shelves
Authors: Abrahams Lauren , Mierzejewski Jose , Dunham Eric , Bromirski Peter D.
Published: March 2023

Flexure and extension of ice shelves in response to incident ocean surface gravity waves have been linked to iceberg calving, rift growth, and even disintegration of ice shelves. Most modeling studies utilize a plate bending model for the ice, focusing exclusively on flexural gravity waves. Ross Ice shelf seismic data shows not only flexural gravity waves, with dominantly vertical displacements, but also extensional Lamb waves, which propagate much faster with dominantly horizontal displacements. Our objective is to model the full-wave response of ice shelves, including ocean compressibility, ice elasticity, and gravity. Our model is a 2D vertical cross-section of the ice shelf and sub-shelf ocean cavity. We quantify the frequency-dependent excitation of flexural gravity and extensional Lamb waves and provide a quantitative theory for extensional Lamb wave generation by the horizontal force imparted by pressure changes on the vertical ice shelf edge exerted by gravity waves. Our model predicts a horizontal to vertical displacement ratio that increases with decreasing frequency, with ratio equal to unity at ~0.001 Hz. Furthermore, in the very long period band (<0.003 Hz), tilt from flexural gravity waves provides an order of magnitude larger contribution to seismometer horizontal components than horizontal displacements from extensional Lamb waves.
UN FANTASMA RECORRE EL CAMPO. COMUNISMO Y POLITIZACIÓN CAMPESINA EN CHILE (1935-1948)
Authors: Acevedo Nicolás
Published: March 2023

El siguiente libro busca responder algunas de estas preguntas, sobre todo porque, a diferencia del movimiento obrero, es poco lo que conocemos en torno a la politización campesina de comienzos del siglo XX. En general, las investigaciones han descrito el proceso la politización obrera, mencionando el papel fundamental que tuvieron los partidos políticos, ya sea el Partido Demócrata, el Partido Obrero Socialista y el movimiento anarquista en el “despertar de los trabajadores”. Por otro lado, han descrito que la relación entre partidos políticos y movimientos sociales se caracterizó por la escasa autonomía de estos últimos en torno a los primeros. Esto incluyó al movimiento campesino, sobre todo en sus primeros años. Pero en las últimas décadas, una serie de estudios han demostrado que los trabajadores agrícolas no fueron “marginados” ni “ausentes” de la política nacional, sino al contrario, las primeras organizaciones campesinas fueron reprimidas y limitadas en el ejercicio sindical, sobre todo entre los años 1938-1952.
Method and results of experimental determination of friction coefficients of some automobile brake shoe
Authors: Holshev N. V. , Konev A. Yu. , Vedishchev S. M. , Prokhorov A. V.
Published: March 2023

Introduction. Road safety is largely determined by the technical condition of the vehicle, and especially control systems. The braking system is one of them. To improve its efficiency, various assistive electronic systems are now widely used. These systems control the vehicle through wheel braking mechanisms. Brake pads are a constituent element of a friction-type wheel brake mechanism. The efficiency of the vehicle braking system depends on its quality, regardless of the presence of auxiliary electronic systems. The use of brake pads with a wide spread of friction coefficients can have a significant impact on braking performance.Materials and methods. To conduct experimental studies, a methodology for conducting them and processing experimental data was developed, as well as a laboratory setup was made. Arduino Uno R3 analog-to-digital converter was used as an instrumental component of the stand for converting mechanical movements into an electronic signal.Results. In accordance with the proposed methodology, four pairs of brake pads were tested. As a result of processing the experimental data, it was found that the difference in the values of the friction coefficients of the brake pads can cause a difference in the magnitude of the braking forces on the wheels from 8 to 19%.Discussion and conclusions. The difference in the coefficients of friction of the brake pads has a significant impact on the magnitude of the braking forces and the stability of the vehicle during braking. One of the reasons for this may be the poor quality of the pad material or a violation of operating conditions. The proposed improved technique for determining the coefficients of sliding friction makes it possible to obtain more accurate values through the use of an analog-to-digital converter, reducing the influence of the accuracy of measuring instruments and the human factor.
Motor driving force of bridge-type crane lifting mechanism under real operating use
Authors: Nazarov A. N.
Published: March 2023

Introduction. The requirement for modelling the dynamic processes of a hoisting mechanism in real operating situations has been revealed. The necessity of increasing the accuracy of moving effort description for the most common types of crane hoist drive control has been determined.Materials and Methods. The operation of a single-speed electric motor with squirrel-cage rotor without speed control, with a phase rotor and additional resistors in the rotor winding and with a squirrel-cage rotor and control by a frequency converter has been considered. The static characteristic of the electric motor is taken as the initial function. The Clauss formula with the corresponding values of the parameters synchronous speed, critical force and critical slip was used to take into account the driving force of the motor for frequency control and for relay-contactor control and a motor with a phase-rotor and additional resistances in the rotor circuit.Results. The dependences for the motor driving force with the most common methods of speed control of the crane hoisting mechanism drive are presented. In the case of the frequency control system, the form of the motor driving force is given in the case of steady-state motion and in the case of transient starting/braking processes when the corresponding algorithms are implemented by a frequency converter. Experimental and theoretical graphs of the load lifting processes for the cases of lifting with pickup in the relay-contactor control system and with elastic pickup in the frequency control system are given.Conclusion. The conclusion about applicability of static mechanical characteristic for description of electric motor operation in crane drives is given. The presented dependences provide an opportunity to model the full working cycle of the hoisting mechanism. The dependences are valid both during steady motion of the mechanism and during transients. It is concluded about the use of the dynamic model taking into account the presented form of the motor driving force for practical purposes for the analysis of the crane operation with regard to the effect of the lifting capacity limiter.