bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Human Activities in the Coastal Zone of Laizhou Bay
Authors: Wang Min , Han Mei , Hui Hongkuan , Li Yunlong 
Published: July 2021

Abstract
The serious destruction of resources and environment in Laizhou Bay has attracted extensive attention of researchers. This study mainly analysed the changes of fish structure and environment in the coastal zone of Laizhou Bay caused by human activities. By consulting literatures and field measurements, the changes of dominant fish species, coastline and sea water intrusion were analysed. The results showed that dominant fish species in Laizhou Bay change from high-economic species to low-economic species under the influence of human activities, and the coastline erosion was serious, and the area of sea water intrusion was also increasing year by year. It is concluded from the research results that human activities had a significant impact on the structure of fish school and the environment. It is necessary to arrange human activities in an appropriate amount to reduce the overexploitation of resources in order to restore the fishery resources and environment in Laizhou Bay.
Removal of Lead(II) and Zinc(II) from Aqueous Solutions Applying Fibber Hemp (Cannabis sativa L.)
Authors: Paliulis Dainius 
Published: July 2021

Abstract
Lead and zinc are heavy metals with toxic properties. These chemical elements are found in wastewater. The article deals with the removal of lead(II) and zinc(II) ions from polluted water using adsorption. As object of researches was selected natural polymer - fibber hemp (Cannabis sativa L.). Big quantities of fibber hemp are produced as waste in textile, agricultural industry, and therefore their usage could help to solve two problems -reducing quantity of fibber hemp as waste and reducing of water pollution by heavy metals. Pb(II) and Zn(II) ions adsorption with fibber hemp was investigated for contact time, pH, and heavy metal ions concentration impact. Pb(II) and Zn(II) ions biosorption rate was highest within the first hour, with optimal their biosorption recorded at pH = 5.0. Highest lead and zinc ions removal efficiency was recorded after 240-480 min and reached 60.5 and 61.7 % respectively. This study demonstrated the applicability and effectiveness of fibber hemp in lead and zinc ions removal, which could be applied for the sewage treatment plant in small scale.
Mobility of Potentially Toxic Elements from the Abandoned Uranium Mine’s Spoil Bank
Authors: Khumalo Lamlile , Heltai György , Várhegyi András , Horváth Márk 
Published: July 2021

Abstract
This study is part of the ongoing environmental monitoring program of the abandoned Mecsek uranium mine during the remediation period. During this program on the recultivated No.1 spoil bank, the radioactivity and the potentially toxic element (PTE) contents in the covering soil had shown some anomalies which refers to possible migration alongside the slope. Therefore, in a previous study, soil and plant samples were collected from top to bottom position of the slope and the total element content was determined by multi-elemental inductively coupled plasma-optical emission spectrometry. The results have indicated that there was a high possibility for PTEs to be mobile and available for uptake by plants. To confirm this indication in the present study for the soil samples the BCR sequential extraction procedure was applied to characterise the environmental mobility of PTEs, and it was compared with soil pH and cation exchange capacity (CEC). The results indicated that the ratio of Cd, Co, Mn, Pb, and U in the non-residual fractions ranged between 36.8 to 100 % and increased from top to bottom direction. The comparison showed that the samples with the lowest pH and CEC had the most mobility of the PTEs. The distribution of U, Cd, Mn, Co, and Pb in fractions indicated that some parts of the spoil deposit require additional steps to hinder the migration through the covering soil layer, and the BCR sequential extraction procedure has proven to be useful in providing information for the planning and management of remediation operations.
Compost Produced with Addition of Sewage Sludge as a Source of Fe and Mn for Plants
Authors: Gondek Krzysztof , Mierzwa-Hersztek Monika , Kopeć Michał , Spałek Iwona 
Published: July 2021

Abstract
Direct application of sewage sludge to soil is controversial due to, among others, its highly variable composition, odour, and risks for health. The obtained composts with the addition of sewage sludge were tested for the contents and availability of manganese and iron. Once composts were applied to the soil, their effect on the content and availability of Mn and Fe in soil and bioaccumulation in the plant were determined. The addition of sewage sludge enriched composts with manganese and iron, but did not increase the content of water-extracted forms of Mn and Fe. The compost with addition of biochar had more organic matter-bound forms of Mn and Fe. Composts amended with sewage sludge had lower effect on the amount of Poa pratensis L. biomass than maize straw compost. The content of Mn and Fe in Poa pratensis L. was in the range permissible for biomass used as fodder. Smaller addition of all composts to the soil significantly increased the content of mobile manganese forms; however, neither the type nor the dose had effect on the content of iron mobile forms. There was no significant differences in the content of organic matter-bound forms of Mn and Fe in soil after the application of composts.
Mycoremediation of Soil Contaminated with Cadmium and Lead by Trichoderma sp.
Authors: Bandurska Katarzyna , Krupa Piotr , Berdowska Agnieszka , Jatulewicz Igor , Zawierucha Iwona 
Published: July 2021

Abstract
Conducted research determined the effect of the Trichoderma fungi on the presence of cadmium and lead ions in the soil contaminated by mentioned elements. The aim of the study was to demonstrate whether the fungi of this kind can contribute to remediation of soil by the immobilization of heavy metals. Experiments were conducted in laboratory conditions. The vaccine containing spores of Trichoderma asperellum was introduced into the soil contaminated with cadmium and lead by direct injection. Analyses of the soluble fraction of selected heavy metals were performed after 3 and 15 days of cultivation using atomic absorption spectrometry (AAS). Statistical significant positive effects on the immobilization of lead ions and no statistical differences in inhibition of cadmium translocation were observed. The results showed that Trichoderma fungi are suited to support the process of environment remediation by removal of lead. This suggests possible application of Trichoderma asperellum in mycoremediation and supporting role in phytoremediation of soil.
Digital Twin For Fatigue Analysis
Authors: Chabod Amaury , Baron Nicolas 
Published: July 2021

Abstract
The main design parameters that impact the fatigue of components are geometry, material and loading. Simulation with Finite Element Analysis (FEA) and tests on a vibrating table are often used to understand the dynamic behaviour of components and thus validate those items.
Accelerated tests are used for the mission profile and test definition, as described in GAM-EG-13, MIL-STD-810F and RTCA DO-160E. The shock response spectrum (SRS) and the extreme response spectrum (ERS) allow for a comparison of the power spectrum density (PSD) and the acceleration factor applied in terms of fatigue severity through the fatigue damage spectrum (FDS). In addition, the hypothesis of linear damage accumulation enables the combination of several events for specifying a mission profile. Ultimately, the mission profile, which represents a usage that might span over several years, can be reduced to a shorter duration with a damage extraction technique. This is particularly useful for the definition of vibrating table specifications.
An advantage of the virtual vibrating table is the reduction of the number of prototypes and the understanding of failure modes. To achieve this objective, finite element analysis in the frequency domain (harmonic analysis) is used and the structural stress response is evaluated with a PSD loading. A statistical model of rainflow allows assessing the damage on the components. The presentation also shows the effects of the damping factor on damage results. To achieve accurate results and define a Digital Twin, the correlation between test results and the finite element analysis is fundamental. Experimental modal analysis, based on the measured acceleration responses, helps to validate calculated modal frequencies and to assess the damping for each mode. This study shows the importance and the sensitivity on damping of the structural response, and in turn on fatigue.
Analysis of the Corrosion Resistance of Aircraft Structure Joints with Double-Sided Rivets and Single-Sided Rivets
Authors: Kamińska Paulina , Synaszko Piotr , Ciężak Patryk , Dragan Krzysztof 
Published: July 2021

Abstract
An important factor having a negative impact on the technical condition of aircraft structure elements is the adverse effect of the atmosphere, which causes formation of corrosion in aircraft structures, especially in riveted lap joints. The electric potential difference between the sheet material and the rivet, in the presence of humid air, may cause electrochemical corrosion. The paper presents specimens that imitate the repair on the Mi-24 helicopter with the use of blind rivets in places where solid double-sided rivets could not be used. The aim of the research was to assess the corrosion resistance of lap joints with the use of single-sided and double-sided rivets. The analysis of corrosion resistance was carried out based on accelerated aging tests in a salt spray chamber. The salt chamber tests were aimed at determining the changes taking place in the specimens exposed to the marine environment. In the course of periodic observations changes in the mass of the specimens and in the form of corrosion losses were recorded. These activities were aimed at determining whether the exposure of specimens in the salt chamber causes electrochemical corrosion or pillowing. In addition, the specimens were subjected to static strength tests to assess the effect of corrosion on the strength properties of riveted joints.
Dynamic Fatigue Tests Of Landing Gears
Authors: Skorupka Zbigniew 
Published: July 2021

Abstract
Landing gears are one of the main components of an aircraft. The landing gear is used not only during take-off and landing but also, in most cases, during ground manoeuvres. Due to its function, the landing gear is also one of the key safety components of the aircraft due to dissipating landing loads acting on the aircraft. The mentioned loads come from both the vertical and horizontal speeds during touchdown and by the aircraft’s losing the speed by braking. The landing gear is then loaded with constantly changing forces acting in various directions during every landing, with the only difference coming from their magnitude. The repeatable loading conditions cause significant wear of the landing gear. This wear can be divided into two categories, one is the wear of consumable parts such as the brake linings and the other is the fatigue wear of the structural components. The latter type of wear is much more dangerous due to its slow, and in many cases, unnoticeable progression. Fatigue wear can be estimated by numerical analyses – this method works with a great degree of probability on single components but due to the complexity of the landing gear as a whole it is not precise enough to be applied to the full structure. In order to evaluate the fatigue of the whole landing gear the best method accepted by regulations is the laboratory testing method. It involves a series of various drop tests resembling the real landing condition distribution. The aim of the tests is to check the fatigue wear of the landing gear and to prove its reliability for certification and/or operational purposes.
In this paper the author describes the basics of the landing gear fatigue wear, possibilities of its evaluation and presents laboratory dynamic method used for extensive tests in life-like operation conditions.
Modular Test Stand for Fatigue Testing of Aeronautical Structures – Verification of Assumptions
Authors: Leski Andrzej , Wronicz Wojciech , Kowalczyk Piotr , Szmidt Michał , Klewicki Robert , Włodarczyk Karol , Uliński Grzegorz 
Published: July 2021

Abstract
The Modular Test Stand was developed and manufactured to decrease the cost of fatigue testing and reduce the time of its completion as well as to enable testing specimens under more complex load conditions. The stand consists of three connected sections, similar to a wing box, all being loaded in the same way. Thanks to that, several specimens can be tested simultaneously. This configuration requires that stress and strain distribution should be reasonably uniform, as assumed in the design stage. The structure can be loaded with bending or torsion. A whole section, selected structural node or a specimen mounted in the structure as well as a repair or a sensor can be a test object.
Two stands, one for bending and one for torsion were prepared. This paper presents the verification of the assumed strain and stress distributions on the skin panels. The measurements were performed with the use of Digital Image Correlation (DIC) as well as strain gauges. DIC measurements were performed on one skin panel of the central section. Five strain gauge rosettes were installed on both panels of the one section. In addition, one rosette was applied to one skin panel in each of two other sections. Measurements were performed on the stand for torsion as well as on the stand for bending. The results of DIC analysis and strain gauge measurement during torsion show uniform shearing strain distributions on the panels. During bending, on the tensioned side, the strains obtained indicate quite uniform strain distributions. On the compressed side, local buckling of the skin panels results in high strain gradients. Strain levels obtained with the use of a DIC analysis and strain gauge measurements were similar. Moreover, horizontal displacements of markers in the spar axis during bending was determined based on a series of photographic. The deflection line obtained in this way has a shape similar to arc, which is characteristic of the constant bending moment.
The stand was tested with torsional and bending loads in order to verify the design assumptions. The results of strain distributions on the skin panels with the use of DIC and strain gauges as well as the deflection line of the spar axis indicate that the Modular Test Stand performs as assumed and can be used for tests.
Impact of Manufacturing Tolerances on Stress in a Turbine Blade Fir-Tree Root
Authors: Moneta Grzegorz , Jachimowicz Jerzy 
Published: July 2021

Abstract
Low Cycle Fatigue (LCF) is one of most common mechanisms behind turbine blade failures. The reason is high stress concentration in notch areas, like fir-tree root groves, which can cause cyclic stress beyond the safe threshold. The stress levels strictly depend on the manufacturing accuracy of the fir-tree lock (for both fitted together: blade root and disk groove). The probabilistic study aimed at determination of stress was performed using Finite Element Method (FEM) simulation on a population of 1000 turbine models (disk + blades +friction dampers), where fir-tree lock dimensions were sampled according to the normal distribution, within limits specified in the documentation. The studies were performed for different manufacturing quality levels: 3-Sigma, 6-Sigma and 3-Sigma with tolerance ranges reduced twice. Based on the results, the probabilistic distributions, probabilities and expected ranges of values could be determined for: material plastification, stress, strain, LCF lifetime, etc. The study has shown how each tooth of the root is loaded and how wide a stress range should be expected in each groove. That gives information on how the definition of tolerances should be modified to make the construction more optimal, more robust, with lower likelihood of damage, taking into account the cost-quality balance. It also shows how the Six Sigma philosophy can improve the safety of the construction, its repeatability and predictability. Additionally, the presented numerical study is a few orders of magnitude more cost- and time-effective than experiment.
Some Comments on Fatigue Life Tests of Aircraft Cable Control Systems
Authors: Brzęczek Józef 
Published: July 2021

Abstract
Cable control systems are widely used in aircraft and gliders. This paper deals with the problem of collecting real loads acting cable control systems and cable tests preparation (load spectrum) and performance. The author proposes a method for defining real loads acting on control systems, preparing and carrying out fatigue tests of cables revealing symptoms of fretting. The fatigue tests results can be used to predict service life, to plan and prepare periodic and details inspections. This method could be used to increase service life of aircraft control cables and could help to replace the commonly used Time-Based Maintenance (TBM) strategy with the Damage Tolerance (DT).
Service Life Extension of Parachutes with Use of Non-Desctructive and Partially Destructive Testing Methods of Textile Materials
Authors: Szafran Krzysztof Stanisław , Kramarski Ireneusz 
Published: July 2021

Abstract
The specificity of personal rescue and reserve parachutes is the fact that they are practically never used for jumping during their service life as they are intended for use only in emergency situations. Therefore, these parachutes throughout the entire period of use are only periodically aired and repacked every 6-12 months. Airing and repacking is necessary even if the parachute is only stored. Rescue and reserve parachutes’ components wear unevenly because the canopy with the suspension lines is inside the container and the cover, while the external components of the harness and the container undergo typical operational wear. Therefore, the service life of rescue parachutes can even reach 20 years (this refers to the canopy with the suspension lines alone). During normal exploitation, parachutes are subjected to non-destructive visual and tactile inspection in preparation for packing. When a parachute reaches its maximum service life, extension of its service life can be calculated based on its technical condition. The procedure for extending parachute’s service life involves non-destructive tests at a fabric air permeability test stand and partially destructive tests at the strength test stand. In the paper, both methods are described and their advantages and disadvantages are discussed. Also, observations some regarding the packers’ work and the desired new properties of raw materials that could be introduced to the parachute industry are presented.
Mechanical Tests Applied to Structural Health Monitoring: An Overview of Previous Experience
Authors: Baran Marta , Nowakowski Dominik , Lisiecki Janusz , Kłysz Sylwester 
Published: July 2021

Abstract
Laboratory for Materials Strength Testing (LMST) has been conducting accredited mechanical research for aviation from 2003. Among accredited procedures are e.g. low and high cycle fatigue tests, fracture toughness tests and fatigue crack growth rate tests. The main goal of them is obtaining materials constants and characteristics. However knowledge how to conduct these tests could be used also in other applications, for instance in the work on development of Structural Health Monitoring systems (SHM). When cracks propagate in a controlled way in laboratory conditions, it allows verifying the operation of a single sensor or a network of sensors.
In this paper, an overview of mechanical tests carried out at the Laboratory for Materials Strength Testing within Air Force Institute of Technology (AFIT) work on research and development of SHM systems is presented. Specimens prepared from materials such as aluminum alloys (among other withdrawn PZL-130 Orlik TC-II aircraft) and CFRP composite were tested under different mechanical loads, i.e., cycle and impact loads. In the presented research, both constant amplitude and spectrum loads were applied.
Digital Innovations and Smart Solutions for Society and Economy: Pros and Cons
Authors: Sikorski Marcin 
Published: July 2021

Abstract
Recent developments in artificial intelligence (AI) may involve significant potential threats to personal data privacy, national security, and social and economic stability. AI-based solutions are often promoted as “intelligent” or “smart” because they are autonomous in optimizing various processes. Because they can modify their behavior without human supervision by analyzing data from the environment, AI-based systems may be more prone to malfunctions and malicious activities than conventional software systems. Moreover, due to existing regulatory gaps, development and operation of AI-based products are not yet subject to adequate risk management and administrative supervision. Resonating to recent reports about potential threats resulting from AI-based systems, this paper presents an outline of a prospective risk assessment for adaptive and autonomous products. This research resulted in extensive catalogs of possible damages, initiating events, and preventive policies that can be useful for risk managers involved in conducting risk assessment procedures for AI-based systems. The paper concludes with the analysis and discussion of changes in business, legal, and institutional environments required to ensure the public that AI-based solutions can be trusted, are transparent and safe, and can improve the quality of life.
Introducing the Jordan Labor Market Panel Survey 2016
Authors: Krafft Caroline , Assaad Ragui 
Published: July 2021

Abstract
This paper introduces the 2016 wave of the Jordan Labor Market Panel Survey (JLMPS). It is an essential reference for users of this innovative and valuable dataset, which adds to the growing series of labor market panel surveys (LMPSs) produced by the Economic Research Forum (ERF). The 2016 wave is a follow-up on the initial 2010 wave. There has been substantial turmoil in the region since 2010, including the onset of the Syrian conflict and the influx of refugees into Jordan. The 2016 wave over-sampled areas with a high proportion of non-Jordanians to be able to represent and examine this important population. The paper describes this sampling strategy, attrition from 2010 to 2016, and weighting that corrects for attrition and accounts for the sampling strategy. We compare key demographic measures and labor market statistics with other sources of data on Jordan to demonstrate the sample's representativeness. The data provide an important opportunity for a detailed analysis of Jordan's changing labor market and society.
Better together: Active and passive labor market policies in developed and developing economies
Authors: Pignatti Clemente , Van Belle Eva 
Published: July 2021

Abstract
We investigate the macroeconomic impact of public expenditure in active labor market policies (ALMPs) and passive labor market policies (PLMPs) on main employment indicators (i.e., unemployment, employment, and labor force participation) for a large and novel panel database of 121 countries (36 developed, 64 emerging and 21 developing economies). Compared to previous studies, we include for the first time evidence from developing and emerging economies and explicitly examine the possible presence of complementarities between active and passive policies. We find that the interaction between interventions is crucial, as the effect of spending in either of the two policies is more favorable the more is spent on the other. Even the detrimental labor market effects of passive policies disappear on the condition that sufficient amounts are spent on active interventions. This complementarity seems even more important for emerging and developing economies.