bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Salinity on the Macro- and Micronutrient Contents of a Halophytic Plant Species (Portulaca oleracea L.)
Authors: Bekmirzaev Gulom , Ouddane Baghdad , Beltrao Jose , Khamidov Mukhamadkhon , Fujii Yoshiharu , Sugiyama Akifumi
Published: May 2021

The main purpose of the two consecutive experimental studies presented here was to compare the effect of salinity on nutrients in leaves of the halophytic plant species Portulaca oleracea L. and in soil. The first experiment was conducted to study the effect of salinity on plant growth, biomass accumulation, yield, root layer development, salt accumulation, and the dynamics of changes in mineral substances in plants and soil. In the second experiment, P. oleracea seeds were sown directly into salinized soil (treated immediately before plant growth) to determine the nutrient levels in leaves and soil. Three salinity treatments (saline water solution with NaCl: T1, 5 dS m−1; T2, 9.8 dS m−1; and T3, 20 dS m−1) and a control treatment (T0, 1 dS m−1) were used in the first experiment. The soil in the second experiment was used in a previous study (performed immediately before P. oleracea growth) (salinized soil: T1, 7.2 dS m−1; T2, 8.8 dS m−1; T3, 15.6 dS m−1; T0, 1.9 dS m−1). The plants were irrigated with tap water at amounts in the range of 0.25–0.50 L/pot. Analysis of the experimental results showed that P. oleracea is resistant to salinity, is able to remove ions (400–500 kg ha−1 NaCl), and can be grown in saline soil. The results indicated that P. oleracea is able to grow in high-salinity soil. This finding was confirmed by the dry matter obtained under high-salinity conditions. Salinity stress affected nutrient uptake in leaves and soil.
Divide et Disperda: Thirty Years of Fragmentation and Impacts on the Eco-Mosaic in the Case Study of the Metropolitan City of Naples
Authors: Zuzolo Daniela , Guarino Carmine , Formato Christian , Tartaglia Maria , Sciarrillo Rosaria , Paura Bruno , Prigioniero Antonello
Published: May 2021

Nowadays, anthropic pressures are continuously transforming the landscape mosaic, leading to issues related to habitat fragmentation and the loss of ecosystem functions. In this study, a landscape-change analysis over the 1990–2018 timeframe of the case study area of Metropolitan City of Naples (MCN) (southern Italy) was performed to evaluate trends, causes, and results of the landscape transformations. We preliminary performed a spatial–temporal fragmentation-expansion analysis in the MCN through the landscape expansion index (LEI), and subsequently determined the impacts on the eco-mosaic. The multitemporal analysis (1990–2018) highlighted an urban expansion in the MCN. The LEI analysis depicted a dual tendency in the increased fragmenting of the MCN’s eco-mosaic. The urban landscape has compacted in the hollow areas, and in the meantime there has been a sprawling expansion of the urban fabric. The most impacted land-use category was “Agricultural areas”, of which 57.42 km2 have been lost in 28 years, with negative impacts on ecological connectivity. Finally, we investigated the relationship between the increase and type of landscape fragmentation and the demographic flows over time. We found that the areas affected by demographic growth were the same ones characterized by an edge expansion of the urban patterns. Conversely, where there has been a demographic decrease, an infilling behavior of urban fabric has been noted. This study highlights a possible correlation between the expansion type of the urban fabric and the demographic flows in a region as a main driver. The outcome of 30-year transformations is the actual ecological network in which Core Areas, Buffer Zones, and Primary Connections covered 35.3%, 11.1%, and 39.6%, respectively, of the total surface of the MCN, covering an overall area of 1008.4 km2.
Alternative between Revitalisation of City Centres and the Rising Costs of Extensive Land Use from a Polish Perspective
Authors: Jadach-Sepioło Aleksandra , Zathey Maciej
Published: May 2021

The phenomenon of spatial chaos is ever-growing challenge in Poland. Its most common explanations are the weaknesses of spatial planning and the households’ economic-based decisions of building a house in the suburbs. In this context, Polish publications lack analyses of the impact of local authorities’ on shaping conditions for the development of new housing and renovation of the existing ones. The authors put forward a thesis about the persistence of an extensive land use policy model in Poland, in which local governments create conditions favouring area-consuming approach to locating buildings. At the same time, the same local governments allow de-agriculturalisation of land plots with a consequence that newly developed areas are not equipped with utilities (e.g., sewage or heating networks). Chaos in the development of residential areas is also illustrated by another phenomenon. Local authorities designate large degraded and revitalisation areas. This results in the dispersed effects. The article concentrates on these three symptoms of spatial chaos in Poland, i.e., random and dispersed expansion of new investments in sewage system, lack of integration between district heating systems and direction of residential development and dispersed effects of revitalisation, which cannot prevent flight from blight. The obtained results allowed to confirm the thesis about the extensive land use policy model in Poland.
Exploring the Transformation in the ‘Spirit of Place’ by Considering the Changed and Unchanged Defensive Spaces of Settlements: A Case Study of the Wugoushui Hakka Settlement
Authors: He Yanfeng , Chen Chie-Peng , Chou Rung-Jiun , Luo Haifeng , Hou Jing-Shoung
Published: May 2021

Over generations, economic development has accelerated traditional settlements in Taiwan while losing traditional culture. In Hakka villages, this is manifested in the changes in defensive spaces, the ‘spirit of place,’ and land use. Although some progress has been made through research into related issues, a correlated view has been missing. To explore the connection between the ‘spirit of place’ and defensive spaces in Wugoushui, a traditional representative settlement in Taiwan, this paper probes three questions: What are the changes in defensive spaces? What are the changes in the spirit of place? What are the connections between them? Taking the sixteen criteria of secure defensive space as the theoretical foundation, through more than a year of structured observations and in-depth interviews with ten representative residents, and based on context analysis and site analysis of the information collected, this paper has concluded that, although the actual functionality of Wugoushui settlement’s spiritual, behavioural, and physical defences have disappeared, cultural characteristics related to the settlement traditions, including religious beliefs, trust, sense of belonging, street network, nodes, institutions, territory, and social networks, constitute a concrete manifestation of the defensive space and the spirit of place as of today. This research contributes to developing a theory of the relevance of the spirit of place to the defensive space of settlements from a sustainability perspective and improving the cultural preservation and land management of traditional settlements.
Measuring the Impact of the Multiple Cropping Index of Cultivated Land during Continuous and Rapid Rise of Urbanization in China: A Study from 2000 to 2015
Authors: Yang Ren , Luo Xiuli , Xu Qian , Zhang Xin , Wu Jiapei
Published: May 2021

With the continuous and rapid rise of urbanization in China, land use transition research has been carried out extensively. Multiple cropping is the content of land use recessive morphology research, and it is also a common agricultural system in China. Accordingly, further research on multiple cropping index (MCI) can enrich the land use transition research and help to evaluate China’s food security. In order to examine the spatiotemporal changes and factors influencing the MCI of cultivated land in China, we collected MODIS remote sensing image data and land use classification data and conducted a remote sensing inversion on China’s MCI from 2000, 2005, 2010, and 2015. The spatial distributions and evolution processes of the MCI were explored through spatial mapping, statistical analysis, and processing with the Geographic Information System; moreover, the influencing factors of MCI were explored quantitatively with principal component regression. The results were as follows: (1) at the provincial scale, the average MCI across Guangdong, Guangxi, Hainan, Henan, Anhui, and Jiangsu was high; meanwhile, the average MCI across Heilongjiang, Inner Mongolia, Ningxia, and Qinghai was low. Between 2000 and 2015, the number of provinces with low MCI increased gradually, and the average MCI decreased greatly in the southern provinces. (2) At the county scale, the Taihang Mountains, Qinling Mountains, and Hengduan Mountains formed the boundary of China’s single cropping and multiple cropping indices. Dynamic changes in China’s MCI were obvious, and the number of counties with MCI change values lower than 0 increased gradually. Last, (3) natural conditions, nonagricultural process, cultivated land quality, and agricultural intensification demonstrated different degrees of impact on the MCI; in particular, the influence of nonagricultural industries, pesticides, and agricultural plastic film on the MCI proved especially important. Future research should strengthen the existing work on related transformations in farmers’ livelihoods, especially in terms of the return of rural labor force, the body of agricultural production, agricultural ecological issues, and the balance between increased crop production and reduced environmental pollution. In addition, agricultural policy design should pay more attention to cultivated land quality, the farmer who cultivates the land, and the multiple cropping potential of cultivated land.
Understanding the Characteristics and Realization Path of Urban Land Use Transition in the Bohai Economic Rim: An Analytical Framework of “Dominant–Recessive” Morphology Coupling
Authors: Qu Yanbo , Shu Yue , Zong Haining , Si Hongyun , Yang Zhiheng , Liu Tiantian
Published: May 2021

Taking the Bohai Economic Rim as the research area and 44 prefecture-level cities as research objects, on the basis of deepening the connotation of urban land use morphology, we constructed a multi-dimensional indicator system for urban land use transition based on the dominant and recessive morphologies of land use. The patterns of change and transition type are described by single-morphology and comprehensive morphology indices, respectively, while a decoupling elastic coefficient model was used to analyze the coupling relationship and evolution process between the dominant and recessive morphologies of urban land use. The results showed the following: (1) From 2000 to 2020, the single-morphology and comprehensive morphology indices of urban land use in the Bohai Economic Rim both improved, to a certain extent. Overall, the transition types of dominant and recessive morphologies of urban land use showed a development trend, in which the degree of recessive morphology transition was higher than the degree of dominant morphology transition, and the spatial difference of its distribution pattern was obvious. (2) From 2000 to 2020, the type of coupling relationship between the dominant and recessive morphologies of urban land use in the Bohai Economic Rim experienced an evolution, from a single-morphology recession decoupling to a single-morphology leading positive hook. The whole region was in the benign development stage of close coupling, where the degree of transition showed the spatial characteristics of Beijing–Tianjin–Hebei > Liaodong Peninsula > Shandong Peninsula. (3) Differences in the economic levels and urbanization processes of different cities led to different paths, speeds, and degrees of urban land use transition, showing stable, volatile, and non-transition paths. The direct influence of different influencing factors, as well as their potential effects, drive the dominant and recessive morphologies of urban land use to grow, in terms of coupling and synergy, promoting the realization of urban land use transition.
Molecular Insights into the Genetic Variability of ORF Virus in a Mediterranean Region (Sardinia, Italy)
Authors: Coradduzza Elisabetta , Sanna Daria , Rocchigiani Angela M. , Pintus Davide , Scarpa Fabio , Scivoli Rosario , Bechere Roberto , Dettori Maria A. , Montesu Maria A. , Marras Vincenzo , Lobrano Renato , Ligios Ciriaco , Puggioni Giantonella
Published: May 2021

Orf virus (ORFV) represents the causative agent of contagious ecthyma, clinically characterized by mild papular and pustular to severe proliferative lesions, mainly occurring in sheep and goats. In order to provide hints on the evolutionary history of this virus, we carried out a study aimed to assess the genetic variation of ORFV in Sardinia that hosts a large affected small ruminant population. We also found a high worldwide mutational viral evolutionary rate, which resulted, in turn, higher than the rate we detected for the strains isolated in Sardinia. In addition, a well-supported genetic divergence was found between the viral strains isolated from sheep and those from goats, but no relevant connection was evidenced between the severity of lesions produced by ORFV and specific polymorphic patterns in the two species of hosts. Such a finding suggests that ORFV infection-related lesions are not necessarily linked to the expression of one of the three genes here analyzed and could rather be the effect of the expression of other genes or rather represents a multifactorial character.
Idiopathic Intracranial Hypertension: Evaluation of Admissions and Emergency Readmissions through the Hospital Episode Statistic Dataset between 2002–2020
Authors: Mollan Susan P. , Mytton Jemma , Tsermoulas Georgios , Sinclair Alex J.
Published: May 2021

With increasing incidence and prevalence of Idiopathic intracranial hypertension in the UK, the aim of this study was to explore emerging themes in Idiopathic intracranial hypertension using the Hospital Episode Statistics dataset and to quantify recent change in hospital admissions and surgeries performed within England. Methods: Hospital Episode Statistics national data was extracted between 1 April 2002 and 31 March 2019, and followed up until 31 March 2020. All those within England with a diagnosis of Idiopathic Intracranial Hypertension were included. Those with secondary causes of raised intracranial pressure such as tumors, hydrocephalus and cerebral venous sinus thrombosis were excluded. Results: 28,794 new IIH cases were diagnosed between 1 January 2002 and 31 December 2019. Incidence rose between 2002 to 2019 from 1.8 to 5.2 per 100,000 in the general population. Peak incidence occurred in females aged 25–29 years. Neurosurgical shunt was the commonest procedure performed (6.4%), followed by neovascular venous sinus stenting (1%), bariatric surgery (0.8%) and optic nerve sheath fenestration (0.5%). The portion of the total IIH population requiring a shunt fell from 10.8% in 2002/2003 to 2.46% in 2018/2019. The portion of the total IIH population requiring shunt revision also reduced over time from 4.84% in 2002/2003 to 0.44% in 2018/2019. The mean 30 days emergency readmissions for primary shunt, revision of shunt, bariatric surgery, neurovascular stent, and optic nerve sheath fenestration was 23.1%, 23.7%, 10.6%, 10.0% and 9.74%, respectively. There was a peak 30 days readmission rate following primary shunt in 2018/2019 of 41%. Recording of severe visual impairment fell to an all-time low of 1.38% in 2018/19. Conclusions: Increased awareness of the condition, specialist surgery and expert guidance may be changing admissions and surgical trends in IIH. The high 30 readmission following primary shunt surgery for IIH requires further investigation.
Chronic Kidney Disease as a Systemic Inflammatory Syndrome: Update on Mechanisms Involved and Potential Treatment
Authors: Tinti Francesca , Lai Silvia , Noce Annalisa , Rotondi Silverio , Marrone Giulia , Mazzaferro Sandro , Di Daniele Nicola , Mitterhofer Anna Paola
Published: May 2021

Chronic kidney disease (CKD) is characterized by manifestations and symptoms involving systemic organs and apparatus, associated with elevated cardiovascular morbidity and mortality, bone disease, and other tissue involvement. Arterial hypertension (AH), diabetes mellitus (DM), and dyslipidemia, with glomerular or congenital diseases, are the traditional risk factors recognized as the main causes of progressive kidney dysfunction evolving into uremia. Acute kidney injury (AKI) has recently been considered an additional risk factor for the worsening of CKD or the development of CKD de novo. Evidence underlies the role of systemic inflammation as a linking factor between AKI and CKD, recognizing the role of inflammation in AKI evolution to CKD. Moreover, abnormal increases in oxidative stress (OS) and inflammatory status in CKD seem to exert an important pathogenetic role, with significant involvement in the clinical management of this condition. With our revision, we want to focus on and update the inflammatory mechanisms responsible for the pathologic conditions associated with CKD, with particular attention on the development of AKI and AKI-CKD de novo, the alteration of calcium-phosphorus metabolism with bone disease and CKD-MBD syndrome, the status of malnutrition and malnutrition–inflammation complex syndrome (MICS) and protein-energy wasting (PEW), uremic sarcopenia, the status of OS, and the different inflammatory pathways, highlighting a new approach to CKD. The depth comprehension of the mechanisms underlying the development of inflammation in CKD may present new possible therapeutic approaches in CKD and hopefully improve the management of correlated morbidities and provide a reduction in associated mortality.
Interleukin-6 and Interleukin-8 Regulate STAT3 Activation Migration/Invasion and EMT in Chrysophanol-Treated Oral Cancer Cell Lines
Authors: Hsu Po-Chih , Chen Yi-Hsuan , Cheng Ching-Feng , Kuo Chan-Yen , Sytwu Huey-Kang
Published: May 2021

The tumor microenvironment plays a critical role in the control of metastasis. The epithelial–mesenchymal transition (EMT) is strongly associated with tumor metastasis, and consists of several protein markers, including E-cadherin and vimentin. We discovered that chrysophanol causes oral cancer cell apoptosis and the inhibition of migration/invasion and EMT. However, the detailed mechanisms of chrysophanol and its role in oral cancer with respect to the tumor microenvironment remain unknown. In the clinic, proinflammatory cytokines, such as IL-6 and IL-8, exhibit a higher expression in patients with oral cancer. However, the effect of chrysophanol on the production of IL-6 and IL-8 is unknown. We evaluated the expression of IL-6 and IL-8 in human SAS and FaDu oral cancer cell lines in the presence or absence of chrysophanol. The migration and invasion abilities were also determined using a Boyden chamber assay. Our results showed that treatment with chrysophanol significantly decreased the expression of IL-6 and IL-8, as well as the invasion ability of oral cancer cells. Moreover, chrysophanol also attenuated the EMT by increasing the expression of E-cadherin and reducing the expression of vimentin. Mechanistically, chrysophanol inhibited IL-6- and IL-8-induced invasion and STAT3 phosphorylation. IL-6 and IL-8 promote EMT and cell invasion, which is potentially related to the STAT3 signaling pathway in oral cancer. These findings provide insight into new aspects of chrysophanol activity and may contribute to the development of new therapeutic strategies for oral cancer.
Creatine Levels in Patients with Phenylketonuria and Mild Hyperphenylalaninemia: A Pilot Study
Authors: Verduci Elvira , Carbone Maria Teresa , Fiori Laura , Gualdi Claudia , Banderali Giuseppe , Carducci Claudia , Leuzzi Vincenzo , Biasucci Giacomo , Zuccotti Gian Vincenzo
Published: May 2021

Background: Creatine (Cr) levels are strongly dependent on diets, including animal-derived proteins. Cr is an important metabolite as it represents a source of stored energy to support physical performance and potentially sustain positive effects such as improving memory or intelligence. This study was planned to assess Cr levels in PKU children adhering to a diet low in phenylalanine (Phe) content and compared with those of children with mild hyperphenylalaninemia (MHP) on a free diet. Methods: This retrospective pilot study analyzed Cr levels from Guthrie cards in 25 PKU and 35 MHP subjects. Anthropomorphic and nutritional data of the study populations were assessed, compared and correlated. Results: Cr levels of PKU subjects were significantly lower than those of MHP subjects and correlated to the low intake of animal proteins. Although no deficiencies in PKU subjects were identified, PKU subjects were found to have a 26-fold higher risk of displaying Cr levels <25° percentile than MHP counterparts. Conclusions: This pilot study suggests that Cr levels might be concerningly low in PKU children adhering to a low-Phe diet. Confirmatory studies are needed in PKU patients of different age groups to assess Cr levels and the potential benefits on physical and intellectual performance of Cr supplementation.
Semi-Supervised Classification of the State of Operation in Self-Lubricating Journal Bearings Using a Random Forest Classifier
Authors: Prost Josef , Cihak-Bayr Ulrike , Neacșu Ioana Adina , Grundtner Reinhard , Pirker Franz , Vorlaufer Georg
Published: May 2021

For a tribological experiment involving a steel shaft sliding in a self-lubricating bronze bearing, a semi-supervised machine learning method for the classification of the state of operation is proposed. During the translatory oscillating motion, the system may undergo different states of operation from normal to critical, showing self-recovering behaviour. A Random Forest classifier was trained on individual cycles from the lateral force data from four distinct experimental runs in order to distinguish between four states of operation. The labelling of the individual cycles proved to be crucial for a high prediction accuracy of the trained RF classifier. The proposed semi-supervised approach allows choosing within a range between automatically generated labels and full manual labelling by an expert user. The algorithm was at the current state used for ex post classification of the state of operation. Considering the results from the ex post analysis and providing a sufficiently sized training dataset, online classification of the state of operation of a system will be possible. This will allow taking active countermeasures to stabilise the system or to terminate the experiment before major damage occurs.
Analysis of the Influence of Textured Surfaces and Lubrication Conditions on the Tribological Performance between the Compression Ring and Cylinder Liner
Authors: García Carlos Pardo , Rojas Jhan Piero , Abril Sofia Orjuela
Published: May 2021

The objective of the present investigation is to analyze the tribological performance between the union of the cylinder liner and the compression ring under the influence of surface texturing and different lubrication boundary conditions. The analysis is carried out by developing a numerical model, which involves hydrodynamic pressure, lubrication film thickness, textured surface, dynamic forces, and lubrication boundary conditions (starved lubrication and fully flooded lubrication). MATLAB® software (The MathWorks Inc., Natick, MA, USA) is used to solve the equations developed. The results show that the application of a textured surface on the cylinder liner allows obtaining a reduction of 20% and 5% in the asperity contact force and in the total friction force. Additionally, the textured surface allows for a 4% increase in MOFT. In this way, it is possible to reduce the power loss. The implementation of a boundary condition of fully flooded lubrication produces an overestimation in the total friction force due to the greater prominence of the lubrication film. Implementing a textured surface in the ring profile is an alternative way to reduce power loss. The results show that this alternative allows an 8% reduction in power loss.
4-[(4-Chlorophenyl)carbamoyl]butanoic Acid
Authors: Hanifa Bibi , Sirajuddin Muhammad , Bari Ahmed , Lee See Mun , Lo Kong Mun , Tiekink Edward R. T.
Published: May 2021

The X-ray crystal structure determination of the glutaric acid-amide derivative, 4-ClC6H4N(H)C(=O)(CH2)3C(=O)OH (1), is described. The backbone of the molecule adopts an extended, all-trans configuration but the terminal carboxylic acid and phenyl resides are twisted out of the plane through the bridging atoms, as seen in the torsion angles of O(carboxylic acid)–C(m)–C(m)–C(m) [13.9(5)°] and C(m)–N–C(p)–C(p) [47.1(4)°]; m = methylene and p = phenyl. The most striking feature of the molecular packing is the formation of supramolecular tapes mediated by carboxylic acid-O–H⋯O(carbonyl) and amide-N–H⋯O(amide) hydrogen bonding.
Research on Dynamic and Mechanical Properties of Magnetoactive Elastomers with High Permeability Magnetic Filling Agent at Complex Magneto-Temperature Exposure
Authors: Vasilyeva Maria , Nagornov Dmitriy , Orlov Georgiy
Published: May 2021

We consider magnetically active elastomer as a potentially applicable material for manufacturing a working channel of a magnetic pump unit. During the study, the samples were exposed to a magnetic field, a temperature field, and their combination to assess the change in the elastic-strength properties of the final material. For the preparation of samples, high permeability magnetic fillers of various sizes were used in the concentration range of 50–70%. Samples were made with an isotropic and an anisotropic structure. Studies have shown that when using a filler with a relatively coarse fraction, the material has more stable dynamic and mechanical characteristics: the tensile strength of the sample increases by an average of 38%. With the combined effect of magnetic and temperature fields on the material, its elasticity and strength increase by an average of 30% in comparison with the material without external influence. Based on the results obtained, the composition and structural organization of the material, which has the best complex of elastic strength characteristics, has been substantiated. For the manufacture of a pumping unit tube, it is preferable to use an isotropic magnetoactive elastomer with a coarser filler content of about 60%.
Soft Computing Techniques for Laser-Induced Surface Wettability Control
Authors: Ponticelli Gennaro Salvatore , Tagliaferri Flaviana , Genna Silvio , Venettacci Simone , Giannini Oliviero , Guarino Stefano
Published: May 2021

Making decisions and deducing control actions in manufacturing environments requires considering many uncertainties. The ability of fuzzy logic to incorporate imperfect information into a decision model has made it suitable for the optimization of both productivity and final quality. In laser surface texturing for wettability control, in fact, these aspects are governed by a complex interaction of many process parameters, ranging from those connected with the laser source to those concerning the properties of the processed material. The proposed fuzzy-based decision approach overcomes this difficulty by taking into account both the random error, associated with the process variability, and the systematic error, due to the modelling assumptions, and propagating such sources of uncertainties at the input level to the output one. In this work, the laser surface texturing was carried out with a nanosecond-pulsed laser on the surfaces of AISI 304 samples, changing the laser scanning speed, the hatch distance, the number of repetitions, and the scanning pattern. A significant change of the contact angle in the range 24–121° is observed due to the produced textures. The fuzzy maps highlight the inherent uncertainty due to both the laser texturing process and the developed model.
Benchmark for the Coupled Magneto-Mechanical Boundary Value Problem in Magneto-Active Elastomers
Authors: Metsch Philipp , Schiedung Raphael , Steinbach Ingo , Kästner Markus
Published: May 2021

Within this contribution, a novel benchmark problem for the coupled magneto-mechanical boundary value problem in magneto-active elastomers is presented. Being derived from an experimental analysis of magnetically induced interactions in these materials, the problem under investigation allows us to validate different modeling strategies by means of a simple setup with only a few influencing factors. Here, results of a sharp-interface Lagrangian finite element framework and a diffuse-interface Eulerian approach based on the application of a spectral solver on a fixed grid are compared for the simplified two-dimensional as well as the general three-dimensional case. After influences of different boundary conditions and the sample size are analyzed, the results of both strategies are examined: for the material models under consideration, a good agreement of them is found, while all discrepancies can be ascribed to well-known effects described in the literature. Thus, the benchmark problem can be seen as a basis for future comparisons with both other modeling strategies and more elaborate material models.
Study on Performance Tests and the Application of Construction Waste as Subgrade Backfill
Authors: Wang Qingbiao , Zhang Jie , Liu Kang , Xu Andong , Xu Haolin , Yang Mingcong , Wang Cun , Yang Rongshuai , Bao Guangtao , Liu Yunfei , Hu Zhongjing , Shi Zhenyue
Published: May 2021

The application of construction waste as an aggregate in subgrade backfilling is an important recycling option. This study analyzed a subgrade backfill material consisting of lime-fly ash construction waste mixture (LFCWM). Compaction and California bearing ratio (CBR) tests were performed on LFCWM under different cement-aggregate ratios (CARs, 3:7, 4:6, 5:5, 8:2). Different normal stresses (100, 200, and 300 kPa) and aggregate sizes (20%, 40%, 60%, 80% of P4.75) were also evaluated. The experimental results indicated that: (1) when the CAR was 4:6, the optimum water content and the maximum dry density reached their maximum values of 10.1% and 2.03 g/cm3, respectively, the maximum CBR value was 42.5%, and the shear strength reached its maximum value. (2) With an increase in shear displacement, the shear stress showed a rapid initial increase, then a slow decrease, and finally tended to stabilize. (3) Normal stress had a positive effect on the shear strength of the mixture. (4) When P4.75 was 40%, the shear strength of LFCWM was the maximum. The research results have been successfully applied to road engineering, providing an important reference for the application of construction waste aggregate in roadbed engineering.
Effect of Carbon Black on Rutting and Fatigue Performance of Asphalt
Authors: Zhong Kunzhi , Li Zhi , Fan Jianwei , Xu Guangji , Huang Xiaoming
Published: May 2021

As an additive to improve the performance of asphalt binder, tire pyrolysis carbon black is gradually being used in road engineering, but the effect of carbon black (CB) with different particle sizes on asphalt modification remains to be further studied. In this study, three kinds of particle sizes and three kinds of contents of CB were used to modify asphalt, and different tests were conducted to research the high temperature performance and fatigue resistance of carbon black modified asphalt binder. It is found that the addition of CB can enhance the rutting resistance and medium temperature fatigue performance of virgin asphalt binder in general. However, for CB of 270 μm and 2.6 μm, its addition under certain contents lead to the decrease of high temperature performance and fatigue performance of the asphalt binder. For aged asphalt, the addition of CB decreases the rutting resistance and improves the fatigue resistance. The recommended content and particle size of CB are 2% and 2.6 μm. This study refines the complex effects of CB on asphalt properties, providing a reference for determining the size and content of CB in asphalt modification.
Bone Regeneration Using PEVAV/β-Tricalcium Phosphate Composite Scaffolds in Standardized Calvarial Defects: Micro-Computed Tomographic Experiment in Rats
Authors: Badwelan Mohammed , Alkindi Mohammed , Alghamdi Osama , Ahmed Abeer , Ramalingam Sundar , Alrahlah Ali
Published: May 2021

Bone regeneration using beta-tricalcium phosphate (β-TCP) can be practiced using a biocomposite scaffold. Poly(ethylene-co-vinylalcohol)/poly(δ-valerolactone)/β-tricalcium phosphate (PEVAV/β-TCP) composite scaffolds showed promising in vitro results. This study evaluated the bone regenerative potential of PEVAV/β-TCP biocomposite scaffolds in standardized calvarial defects in a rat model over 4 and 10 weeks. Bilateral calvarial defects (5 mm in diameter and about 1.5 mm thick, equivalent to the thickness of the calvaria) were created in 40 male Wistar albino rats. The defects were grafted with either commercially available β-TCP (positive control), PEVAV/β-TCP 70, or PEVAV/β-TCP 50, or left empty (negative control), depending on the group to which the animal was randomly assigned, to be covered before flap closure with resorbable collagen membrane (RCM). At 4 and 10 weeks post-surgery, the collected rat calvaria were evaluated using micro computed tomography (micro-CT) analysis, to assess the newly formed bone volume (NFBV), newly formed bone mineral density (NFBMD), and remaining graft volume (RGV). The results showed that calvarial defects grafted with the PEVAV/β-TCP biocomposite exhibited higher NFBV than did control defects, both at 4 and 10 weeks post-surgery. Furthermore, calvarial defects grafted with PEVAV/β-TCP 70 showed the highest NFBV among all grafting conditions, with a statistically significant difference recorded at 10 weeks post-surgery. The PEVAV/β-TCP composite scaffold showed potentiality for the regeneration of critical-sized calvarial bone defects in a rat model.
High UV and Sunlight Photocatalytic Performance of Porous ZnO Nanostructures Synthesized by a Facile and Fast Microwave Hydrothermal Method
Authors: Ferreira Sofia Henriques , Morais Maria , Nunes Daniela , Oliveira Maria João , Rovisco Ana , Pimentel Ana , Águas Hugo , Fortunato Elvira , Martins Rodrigo
Published: May 2021

The degradation of organic pollutants in wastewaters assisted by oxide semiconductor nanostructures has been the focus of many research groups over the last decades, along with the synthesis of these nanomaterials by simple, eco-friendly, fast, and cost-effective processes. In this work, porous zinc oxide (ZnO) nanostructures were successfully synthesized via a microwave hydrothermal process. A layered zinc hydroxide carbonate (LZHC) precursor was obtained after 15 min of synthesis and submitted to different calcination temperatures to convert it into porous ZnO nanostructures. The influence of the calcination temperature (300, 500, and 700 °C) on the morphological, structural, and optical properties of the ZnO nanostructureswas investigated. All ZnO samples were tested as photocatalysts in the degradation of rhodamine B (RhB) under UV irradiation and natural sunlight. All samples showed enhanced photocatalytic activity under both light sources, with RhB being practically degraded within 60 min in both situations. The porous ZnO obtained at 700 °C showed the greatest photocatalytic activity due to its high crystallinity, with a degradation rate of 0.091 and 0.084 min−1 for UV light and sunlight, respectively. These results are a very important step towards the use of oxide semiconductors in the degradation of water pollutants mediated by natural sunlight.
Influence of Subsequently Applied Mechanical and Thermal Loads on Surfaces Ground with Mechanical Main Impact
Authors: Strunk Rebecca , Borchers Florian , Clausen Brigitte , Heinzel Carsten
Published: May 2021

To generate advanced properties for the wear resistance and fatigue life of components and allow for an improved, application-oriented development of part specifications, a precisely tailored initial machining or manufacturing process is necessary. In addition, it is important to know how subsequent machining steps or operational loads affect the components’ condition. Residual stresses are a meaningful measurand for evaluating the modifications that a machining process induces into the material. The desired modifications should be specified regarding the final state for the required operational behavior. Thus, the stability of the modifications can be considered so that they can be beneficial in service. This investigation is part of fundamental research in the field of the Collaborative Research Center (CRC) “Process Signatures”. By applying defined selected loads, the effects on machined surface layers are investigated since machined components are exposed to further loads during use. For this reason, experimental process chains are applied in this work to grind-strengthened specimens as possible application cases and corresponding loads. These experimental process chains consist of defined mechanical and thermal loads, which are applied to the specimens using a thermal and mechanical testing system. Furthermore, it is investigated how these additional loads affect the modifications previously introduced by the grinding process. The influence of the additional loads is evaluated by using radiographic and electron microscopic examinations. It can be observed that the sequence, as well as the type of the applied loads, play a significant role in the development of the modifications.
Influence of Mechanical Properties of Steel and CFRP Tapes on the Effectiveness of Strengthening Thin-Walled Beams
Authors: Szewczak Ilona , Rozylo Patryk , Rzeszut Katarzyna
Published: May 2021

The paper presents a comparison of the effectiveness of strengthening steel thin-walled, cold-formed sigma beams with CFRP tapes and steel tapes. For this purpose, three beams without reinforcement (reference beams) of the “Blachy Pruszyński” type, with a cross-section of ∑200 × 70 × 2 and a span of 280 cm, made of S350GD steel grade, were subjected to laboratory tests in the four-point bending scheme. In the next stage the tests included nine ∑200 × 70 × 2 beams reinforced with Sika CarboDur S512 CFRP tape and six ∑200 × 70 × 2 beams reinforced with steel tape made of S235 steel grade. The length of the reinforcement tapes as well made of steel as well of CFRP was of 175 cm. The location of the tapes within the height of the beams’ cross-section was assumed in three variants, namely placing the tape on the upper or bottom flange and on the web. In the case of beams reinforced with CFRP, three beams were tested for each reinforcement location, and in the case of beams reinforced with steel tapes, two beams were tested for each reinforcement location. SikaDur®-30 glue with a thickness of 1.3 mm was used in order to connect steel or CFRP tapes to the beams. The dimensions of the tapes cross-sections in both cases were similar (CFRP tapes: 50 × 1.2 mm, steel tapes: 50 × 1.3 mm). For all types of beams, numerical models were also developed in the Abaqus software. The main aim of this paper was investigation of the influence of mechanical properties of steel or CFRP tapes on the effectiveness of strengthening ∑ beams. For this purpose a comparison of these two solutions with respect to the limitation of displacements and deformations of the beam was performed. The obtained results were considered in the context of the mechanical properties of the materials composing the reinforcement tapes. The tests showed slight differences in the results of strain and displacements obtained for reinforcement made of two different materials. It was also noted that the decisive element was the failure of the joint at the steel-glue interface. Therefore, future studies will pay particular attention to the adhesive layer.
Influence of Zirconia and Organic Additives on Mechanical and Electrochemical Properties of Silica Sol-Gel Coatings
Authors: Gąsiorek Jolanta , Mazur-Nowacka Anna , Szczurek Anna , Babiarczuk Bartosz , Tic Wilhelm Jan , Guziałowska-Tic Joanna , Kaleta Jerzy , Krzak Justyna
Published: May 2021

This paper presents the result of the investigation of organically modified silica (ORMOSIL)-zirconia coatings used to enhance their protective properties, namely corrosion and scratch resistance. Two different materials, i.e., SiO2/ZrO2 and SiO2/GPTMS/ZrO2, were synthesized, measured, and analyzed to find the difference in the used organosilane precursor (dimethyldiethoxysilane and (3-glycidoxypropyl)trimethoxysilane, respectively). SiO2/ZrO2 coatings showed higher hardness than SiO2/GPTMS/ZrO2. Moreover, the value of polarization resistance (Rp) for SiO2/GPTMS/ZrO2 coated 316L steel relative to the uncoated one was obtained. It was nearly 84 times higher. The coating delamination was observed with load 16N. Additionally, the corrosion mitigation for 316L coated by SiO2/GPTMS/ZrO2 was observed even after extended exposure to corrosion agents.
Effect of Heat Treatment Process and Optimization of Its Parameters on Mechanical Properties and Microstructure of the AlSi11(Fe) Alloy
Authors: Jarco Aleksandra , Pezda Jacek
Published: May 2021

The paper presents the results of study concerning the evaluation of the precipitation hardening parameters (temperatures and times of solution treatment and artificial ageing processes) having an effect on mechanical properties, and the change in the microstructure of the EN AC-AlSi11(Fe) alloy. Based on the obtained results and performed statistical analysis, regression equations and the response surface model in the form of spatial and contour plots were determined to illustrate the effects of solution treatment and artificial ageing parameters on the mechanical properties of the investigated alloy. The performed heat treatment had a positive effect on improving the mechanical properties of the alloy versus the initial state. The maximum increase in tensile strength was by 52%, in unit elongation by 56%, in Brinell hardness by 44% and impact strength by 88%. Furthermore, a favorable change was observed in the microstructure of the investigated alloy, especially regarding eutectic silicon precipitations, which underwent partial spheroidization and coagulation after the heat treatment.
Mechanical Behavior Modeling of Containers and Octabins Made of Corrugated Cardboard Subjected to Vertical Stacking Loads
Authors: Gallo Javier , Cortés Fernando , Alberdi Elisabete , Goti Aitor
Published: May 2021

The aim of this paper is to characterize the mechanical behavior of corrugated cardboard boxes using simple models that allow an approach to the load capacity and the deformation of the boxes. This is very interesting during a box design stage, in which the box does not exist yet. On the one hand, a mathematical model of strength and deformation of boxes with different geometry is obtained from experiments according to the Box Compression Test and Edge Crush Test standards. On the second hand, a finite element simulation is proposed in which only the material elastic modulus in the compression direction is needed. For that, corrugated cardboard sheets are glued to build billets for testing, and an equivalent elastic modulus is obtained. This idea arises from the fact that the collapse of the box is given by the local bucking of the corrugated cardboard panels, due to the slenderness itself, and the properties in the compression direction are predominant. As a result, the numerical models show satisfactory agreement with experiments, concluding that it is an adequate methodology to simulate in a simple and efficient way this type of boxes built with corrugated cardboard.
Combining Zirconia and Titanium Suboxides by Vat Photopolymerization
Authors: Schwarzer-Fischer Eric , Günther Anne , Roszeitis Sven , Moritz Tassilo
Published: May 2021

A recently developed multi-ceramic additive manufacturing process (multi-CAMP) and an appropriate device offer a multi-material approach by vat photopolymerization (VPP) of multi-functionalized ceramic components. However, this process is limited to ceramic powders with a certain translucency for visible light. Electrically conductive ceramic powders are therefore ruled out because of their light-absorbing behavior and dark color. The goal of the collaborative work described in the article was to develop a material combination for this multi-material approach of the additive vat photopolymerization method which allows for combining electrical conductivity and electrical insulation plus high mechanical strength in co-sintered ceramic components. As conductive component titanium suboxides are chosen, whereas zirconia forms the mechanically stable and insulation part. Since titanium suboxides cannot be used for vat photopolymerization due to their light-absorbing behavior, titania is used instead. After additive manufacturing, the two-component parts are co-sintered in a reducing atmosphere to transform the titania into its suboxides and, thus, attaining the desired property combination. The article describes the challenges of the co-processing of both materials due to the complex optical properties of titania. Furthermore, the article shows successfully co-sintered testing parts of the material combination of zirconia/titanium suboxide which are made by assembling single-material VPP components in the green state and subsequent common thermal treatment. The results of microstructural and interface investigations such as electrical measurements are discussed.
Analyses of Influence on Chromium Coating after Grinding from the View of Final Microstructure and Microhardness in the Surface Layer
Authors: Náprstková Nataša , Novák Martin , Marek Martin , Šramhauser Karel , Sviantek Jan , Stančeková Dana , Ťavodová Miroslava
Published: May 2021

The article deals with the analysis of chromium layer grinding on a steel substrate, where this issue was addressed with regard to the requirements of the manufacturing sector, specifically in the aerospace industry. The experimental samples were chromium-plated and ground under different cutting conditions by the grooving method of grinding. Two types of grinding wheels for grinding were used, grinding wheel based on SG (solgel) a grinding wheel based on SiC. The resulting microstructure and microhardness in the machined layer were evaluated with using of confocal laser microscopy, inverted materials microscopy, and hardness testing. Based on the results, recommendations were made regarding a suitable approach to grinding the chromium coating. We used a confocal laser microscope and hardness tester for the evaluation of presented values. It was found that, on the base of analyses values, with both grinding wheel and using cutting conditions used, good results have been achieved. This could be stated, because the analysis of the samples microstructure after grinding for the given cutting conditions showed that it is possible that a small influence is completely acceptable from the point of the final product view and there are no major negative phenomena. Measurements of surface microhardness after grinding showed similar results for all samples. The SiC-based grinding wheel showed slightly better results, but both grinding wheels can be used without problems for the presented cutting conditions, and the presented cutting conditions with both grinding wheels can be recommended for the grinding of the given material.