bluuebunny/crossref_metadata_2025_split huggingface dataset:
Double Rough Surface Contact Model and Finite Element Simulation based on Fractal Theory
Authors: SONG Jianfeng , Wang Wenwu , LANG Yuedong , DONG Yonggang , Luo Guoling 
Published: April 2021

Abstract
The contact between two rough surfaces is essentially the contact between micro-bulge of different shapes. In the process of interference fit, the distribution of contact area and contact stress at different positions of the two rough contact surfaces is uneven. In this paper, based on the test results of the morphology of machined surfaces with different surface roughness, a two-dimensional curve model of the contact surface is established according to the W-M fractal function and Matlab software. The contact area and contact load are analyzed with a two-dimensional finite element contact model of the double rough surface that established with Abaqus software. And the effect of surface roughness and surface displacement on the contact area and contact load is analyzed with the finite element contact model.
Acquisition and Analysis Technology of Pyroshock Response on Spacecraft
Authors: Feng Guosong , Yang Guang , Yang Jiang , Ma Gongbo , Wang Rui , Liu Chuang 
Published: April 2021

Abstract
Wide frequency range and high acceleration amplitude are two typical characteristics of transient vibration in the environment of pyroshock on spacecraft. The Piezoelectric accelerometer is widely accepted as the best available transducer for the absolute measurement of vibration. “Ringing” and “Zero Drift” are very easily to occur if the accelerometer is being used to measure transient vibrations outside its useful frequency range. This paper introduced the working principle of piezoelectric accelerometer, The scheme of reducing “Ringing” phenomenon was given, The mechanism of “Zero Drift” phenomenon was analysed. The methods to restrain the “Zero Drift” were discussed from the aspects of the selection of test equipment, the installation of piezoelectric accelerometer and the setting of data acquisition parameters. Finally, the wavelet analysis method was used to decompose and reconstruct the distortion data caused by “Zero Drift”, and the effective pyroshock response signal was extracted.
A Review of The Development of Civil Aircraft Family
Authors: Yongjie Zhang , Yongqi Zeng , Kang Cao , Wenjun Dong , Dayong Dong 
Published: April 2021

AbstractThe development of product family has become a major trend in industrial product research and development, which can meet the needs of market segments, shorten research and development time, reduce research and development costs, and quickly increase market share. The development of civil aircraft family is one of the important characteristics of modern civil aircraft design, which can bring significant economic benefits for aircraft life cycle. In order to meet the needs of the market and realize cost reduction and efficiency increase, the development of civil aircraft family has become the main direction of the development of modern civil aircraft, which has attracted widespread attention, and the major aircraft manufacturers have formed their own series of civil aircraft. Focusing on the development of civil aircraft family, this paper reviews the development of product family, the design of civil aircraft family and the development status of typical civil aircraft family in the field of civil aircraft. Then the challenges and future research directions of civil aircraft family are summarized and discussed.
Rapid Acoustic-vibration Modelling Methods of Solar Arrays in Satellites
Authors: Zhang Jie , liu Huiliang , Xie Weihua , Yin Jiacong , Zhou Jiang 
Published: April 2021

Abstract
Large components outside satellite body are extremely sensitive to the sound field. As the entire satellite acoustic-vibration (hereinafter referred to as acoustic) model is very complex, computationally intensive and time-consuming, the feasibility of only modelling these large components when they are just concerned deserves to be investigated. In this paper, an entire satellite model, a finite element (FE) model a statistical energy analysis (SEA) model of the solar array were firstly established, and then their results and time needed were compared in order to explore the fastest and most efficient modelling method of large components outside satellite body. The results demonstrate that modelling only solar array not the entire satellite is feasible when only it is concerned. The FE model of solar array should be used if the responses at each point are necessary, while the SEA model is recommended if not.
Analysis of Air Distribution and Comfort in Large Space Environment Simulator
Authors: Wenjing Ding , Jinghao Xu , Songlin Hu , Liming Zhang , Ang Li 
Published: April 2021

Abstract
The objective of this paper is to analyze the air distribution and comfort in large space environment simulator under different air supply for the same boundary and initial conditions. This is done by conducting the numerical simulations and contrasting the distribution of velocity and temperature field, PMV-PPD and air age. It can be analyzed that the influence of several air supply on air quality and thermal comfort inside the equipment, which can be as a reference for the improvement and optimization of airflow distribution with the device. This device owns three openable doors, which locate in the bottom, middle and top of the equipment. Open one of them, the ventilation will be achieved. Computational Fluid Dynamics (CFD) is used for it is easier and less time consuming to accomplish that purpose. In general, different air supply have important effect on the air distribution and comfort inside the device. Meanwhile, the comfort is acceptable in most area, however, the air age is on the high side.
Effect of spatial variability of soil properties on permanent seismic displacements of slopes with uniform load
Authors: Alamanis Nikolaos , Dakoulas Panos 
Published: April 2021

Abstract
The purpose of this study is to investigate the development of permanent displacements of earth slopes, with spatially varying properties and a uniform surface load, subjected to a strong seismic excitation. The uncertainties associated with the determination of the mechanical properties of the slopes and the intensity of the seismic excitation, make the use of stochastic methods very attractive. As opposed to deterministic methods, stochastic methods allow an acceptable risk level based on the specifications of each project. Recent research described the spatial variability of soil parameters using the Random Field Theory. Apart from the prescribed statistical characteristics and cross-correlation of the various soil properties, the generated random field variables exhibit autocorrelation, a trend in which the soil properties of a point appear to be correlated with the soil properties of neighbouring points. Among the various random field algorithms, a particularly effective one is the Local Average Subdivision (LAS) method by Fenton and Vanmarcke [1]. To this end, a large number of random fields of soil properties is generated for a natural slope, having prescribed mean value μ, standard deviation σ, cross-correlation coefficients pij
of properties i and j, and spatial autocorrelation lengths lx
and ly
for the vertical and horizontal directions, respectively. The numerical simulations are achieved using an automated procedure, based on collaboration of Mathematica, the incorporated LAS algorithm, and the finite difference program FLAC. The studied slope is loaded with a uniform load and subjected to a seismic shaking of various intensities using a series of acceleration records obtained from the five different earthquakes. The paper focuses mainly on the development of permanent seismic displacements of the slope at the end of ground shaking. It is demonstrated that the spatial variability of soil properties has a significant effect on the values of permanent displacements, resulting to a wide range of displacement variation.
Tensile Strength of Cement Treated Clay
Authors: Azneb A.S , Banerjee Subhadeep , Robinson R.G 
Published: April 2021

Abstract
Tensile properties of geomaterials often play an important role in many geotechnical engineering problems. Compacted soil layers in dams, clay liners in landfills, reinforced earth-retaining wall systems, cement stabilized crushed rocks in pavements, etc. are constantly checked for tensile cracking. This type of cracking happens when the developed tensile stress exceeds the tensile strength of the material. Usually, the tensile strength of natural soil is assumed to be negligible. However, it is proven that cement treated soils possess some amount of tensile strength. The determination of tensile strength of cement treated clay, using a newly developed tensile testing apparatus, is focussed in this study. The existence of an optimum cement content for tensile strength is also discussed.
Role of Geotechnical Engineering in BIM process modelling
Authors: Vaníček I , Jirásko D , Vaníček M 
Published: April 2021

Abstract
BIM “Building Information Model” creates a significant step forward in the whole process of construction. The role of geotechnical engineering will be shown as for classical building engineering so for civil engineering structures. In the first case all upper structures are in interaction with ground (subsoil), when foundation structures are basic element of this interaction. The 3D Ground model and 3D Foundation structure model create therefore one of the first individual parametric elements around basic (coordinating) BIM model. Some specificity will be shown as the impact of step by step creation (nD dimension) of the Ground model for the earliest building conception. Roughly the same is valid for civil engineering structures. Some specificity will be shown for earth structures of transport engineering, as a selection of borrow pit, definition of soil compaction for fill, fill compaction or any other methods of soil improvement and its control as they create important elements for the safe and optimal embankment design and performance. Final 3D Ground model together with 3D Geotechnical structure model (real performance) create the important base for the future decision making, when some changes will occur.
Swell-shrink and hydraulic behaviour of compacted red soil-bentonite mixture
Authors: Devapriya A S , Thyagaraj T 
Published: April 2021

Abstract
Clay liners are provided in waste landfills to prevent the leachate from percolating into underlying soil and ground water and polluting it. Hence, soils used as landfill liners must possess low hydraulic conductivity (< 10−7 cm/s). In the initial as-compacted state, liners satisfy this design criterion. However, in the field, liners are subjected to alternate wet-dry cycles and the initial microstructure of liners change, thereby affecting their hydraulic properties. The present study was conducted on a locally available red soil mixed with bentonite so that it satisfies the requirement of hydraulic conductivity in the as-compacted state. To achieve this objective, identical specimens compacted at optimum moisture content to its maximum dry density were inundated with distilled water under a surcharge load of 12.5 kPa. Upon attainment of maximum swelling, hydraulic conductivity tests were conducted at swollen state under a hydraulic gradient of 20. The soil specimens were then dried at a temperature of 45±2 °C. The weight, height and diameter of specimens were measured continuously during drying to study the shrinkage behaviour of the soil. The dried specimens were subjected to subsequent wet-dry cycles until the specimens reached an equilibrium state and the hydraulic conductivity was determined after each wetting cycle. SEM images were also captured to analyse the changes in the soil structure in the as-compacted state and at the end of different wetting cycles.
Seismic Response of Mechanically Stabilised Earth Retaining Wall
Authors: Joseph M , Banerjee S 
Published: April 2021

Abstract
Mechanically Stabilised Earth retaining wall has become a premier choice of retaining wall design in places where seismic and high vibration loads are frequent. The wall displacement has to be monitored regularly for the safe and economic function of the structure. In the present paper, a numerical study on an MSE wall model under real records of earthquake loading condition using an explicit finite difference program has carried out. A parametric study to scrutinize the influence of strong-motion parameters such as peak ground acceleration and predominant frequency on the permanent displacement of the wall is accomplished. The influence of PGA and frequency of seismic excitation was visible in the results. At higher frequencies, the ground surface is disturbed severely leading to excessive heaving on the surface. The amplification of strong motion along the backfill is observed for low PGA motions, whereas, de-amplification is observed for high PGA motion.
Preliminary study of a bridge abutment settlement considering spatial variability of soil properties
Authors: Pula W , Antczak M , Baginska I , Castrignano A , Vessia G 
Published: April 2021

Abstract
The paper focuses on two-dimensional (2D) analyses of a bridge abutment based on a spatially variable soil. The analysis was carried out to evaluate the settlement of the bridgehead. The numerical model consists of a reinforced concrete support structure, embankment and natural soil. Moreover, frictional contact between the soil and the structure is assumed. As it is well known, the natural soils are spatially highly variable materials, and their mechanical and physical parameters in geotechnical designing, such as a bridge abutment, must be considered variable. Thus, the presented analyses will be devoted to determining the settlement of the structure under study, in probabilistic terms due to soil variability. To this end, Sequential Gaussian Simulation was used to describe the spatial variability of soil parameters. This approach uses geostatistical methods to produce different realizations of soil parameters. A data set of several Cone Penetration Tests (CPT) was used. Simulations were used to calculate the histogram of a bridgehead settlement and search the worst case. Abaqus program and some ad hoc scripts written in Python language were used to perform the analyses. The analysis reflects several stages of abutment’s construction. This allows for a comprehensive analysis of a bridge abutment.
Investigation on the rotational bedding of king piles on the basis of model tests
Authors: Beuße Jannik , Grabe Jürgen 
Published: April 2021

Abstract
Rising world trade and the following consolidation of material flows cause a growing need for bigger bulk carriers. Therefore, the quay walls of the harbours need to be adjusted to realize the depth of the channels. Combined sheet pile walls are used to build quay walls. They consist out of up to 45 m long H-shaped beams and Z-shaped intermediate piles. As a result of the loads, which cause normal forces and bending moments, the stability of the slender profiles is endangered, whereby the deflection of the profile head and the embedding in the soil plays an important role. With the introduction of the standards of DIN EN 1993-5:2010-12 [1] in connection with DIN EN 1993-1-1:2010-12 [2] the proofing of combined walls needs to be done under combination of the resistance against flexural buckling and lateral-torsional buckling. For that reason the rotational resistance of the soil must be considered in order to ensure an economical design. The rotational bedding in cohesive soil is different from that in noncohesive soil and was investigated by laboratory tests as well as by numerical simulations. The results of a FOSTA / aif project with the goal of optimizing the stability procedure of combined walls are be presented.
Investigations of Soil Plugging in Open-Ended Piles with Respect to the Long-Term Behaviour of the Plug
Authors: Henke Sascha 
Published: April 2021

Abstract
Soil plug formation in open-ended piles can lead to a significant increase in bearing capacity as well as in driving resistance. Therefore, it is of main interest to predict the tendency of soil plug formation with respect to the pile geometry, the installation method as well as the penetration depth. In the present paper, the results from in-site testing as well as centrifuge testing are presented. The results are discussed mainly focussing on the tendency of soil plug formation with respect to the above mentioned factors. Furthermore, the results of long term in-site measurements of the earth-pressure at a tubular pile’s toe are evaluated showing that the soil plug remains stable over a period of more than one year although the pile was subjected to loading due to traffic, waves as well as tidal water changes.
Antemortem vs Postmortem Histopathologic and Ultrastructural Findings in Paired Transbronchial Biopsy Specimens and Lung Autopsy Samples From Three Patients With Confirmed SARS-CoV-2
Authors: Gagiannis Daniel , Umathum Vincent Gottfried , Bloch Wilhelm , Rother Conn , Stahl Marcel , Witte Hanno Maximilian , Djudjaj Sonja , Boor Peter , Steinestel Konrad 
Published: April 2021

Abstract

Objectives
Respiratory failure is the major cause of death in coronavirus disease 2019 (COVID-19). Autopsy-based reports describe diffuse alveolar damage (DAD), organizing pneumonia, and fibrotic change, but data on early pathologic changes and during progression of the disease are rare.

Methods
We prospectively enrolled three patients with COVID-19 and performed full clinical evaluation, including high-resolution computed tomography. We took transbronchial biopsy (TBB) specimens at different time points and autopsy tissue samples for histopathologic and ultrastructural evaluation after the patients’ death.

Results
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was confirmed by reverse transcription polymerase chain reaction and/or fluorescence in situ hybridization in all TBBs. Lung histology showed reactive pneumocytes and capillary congestion in one patient who died shortly after hospital admission with detectable virus in one of two lung autopsy samples. SARS-CoV-2 was detected in two of two autopsy samples from another patient with a fulminant course and very short latency between biopsy and autopsy, showing widespread organizing DAD. In a third patient with a prolonged course, autopsy samples showed extensive fibrosis without detectable virus.

Conclusions
We report the course of COVID-19 in paired biopsy specimens and autopsies, illustrating vascular, organizing, and fibrotic patterns of COVID-19–induced lung injury. Our results suggest an early spread of SARS-CoV-2 from the upper airways to the lung periphery with diminishing viral load during disease.
Understanding Breast Implant Illness: Etiology is the Key
Authors: Yang Siling , Klietz Marie-Luise , Harren Anna Katharina , Wei Qiang , Hirsch Tobias , Aitzetmüller Matthias M 
Published: April 2021

Abstract
Because breast augmentation is one of the most popular cosmetic procedures, the issue of implant-related complications has been widely debated ever since the FDA approved the use of implants in 1962. Although decades have passed, breast implant illness (BII) still represents a poorly defined and controversial complication. With ongoing nonscientific discussion in the mainstream media and on social media, revealing the etiology of BII is urgent because knowledge of this subject ultimately influences patients’ decisions. Little or no scientific research is currently available on BII and no final conclusions regarding its etiology, clinical manifestations, diagnostic criteria, or treatment have been made. This review aims to give an overview of the hypotheses on the etiology of BII and seeks inspiration to improve the conditions of BII patients.
Using hair cortisol analysis to understand the biological factors that affect black-footed ferret (Mustela nigripes) stress physiology
Authors: Santymire R M , Ali N , Marinari P E , Livieri T M 
Published: April 2021

AbstractThe black-footed ferret (Mustela nigripes) was driven to near extinction due to habitat loss and an introduced disease, sylvatic plague (Yersinia pestis). After 35 years of breeding in ex situ facilities, the black-footed ferret has been experiencing infertility with seminal traits declining in males and only about a third of breeding-aged females are whelping. Our goal was to use hair cortisol analysis to determine if the ex situ population was experiencing chronic stress that was affecting reproduction by comparing captive ferrets to wild individuals. Our specific objectives were to (i) compare hair cortisol concentrations (HCCs) between age classes (juveniles versus adults), (ii) compare the HCCs of in situ and across different ex situ facilities and (iii) determine the relationship between HCCs and reproductive success. Overall, wild juveniles had higher HCC than wild adults. Our generalized linear mixed model determined that the parameters that best predict HCC for adults were the interactions among sex, in situ versus ex situ facilities and season. During both seasons, wild females had higher HCCs compared to the ex situ females. During the breeding season, male HCCs across breeding facilities varied and males at the breeding facility with the largest ferret habitats had HCCs similar to wild males. At one breeding facility, HCC was higher in males that sired compared to those that did not sire. In conclusion, ex situ ferrets do not have higher HCC than wild individuals when controlling for season and ex situ habitat size, and ex situ males with higher HCC tended to sire. This suggests that HCC may be metabolically driven and/or that low HCC may be an indication of hypothalamus–pituitary–adrenal axis dysregulation and warrants further investigation both for laboratory validation and biological relevance.
For ‘Common Christianity’: War, Peace and the Campaign of the Irish Recruiting Council, 1918
Authors: Maartens Brendan 
Published: April 2021

Abstract
Established towards the end of the Great War, the Irish Recruiting Council was responsible for one of the largest military recruitment campaigns ever waged on Irish soil. Tasked with raising 50,000 volunteers, it produced a wide array of promotional material which included posters, newspaper advertisements and a fortnightly magazine entitled The Irish Soldier. Its work has attracted a measure of scholarly attention, but little is known about its origins, its dealings with authorities in Westminster and Dublin Castle, and the operational difficulties it encountered when attempting to mobilise the public. Even less is known about its newspaper campaign and the reasons behind the continuation of the body in peacetime, when the need for recruits had apparently subsided. This paper addresses these shortcomings by examining the IRC in more detail than has hitherto been achieved in the historiography. In so doing, it calls for a revision of existing understandings of the Council, suggesting that it was not just a recruiting body per se, but a major propaganda agency which portrayed enlistment as a means of uniting a divided country and encouraged Irishmen to mobilise to help resolve long-standing tensions between nationalists and unionists.