bluuebunny/crossref_metadata_2025 huggingface dataset:
Greener and Leaner: Lower Energy and Water Consumption, and Reduced Work Orders, in Newly Constructed Boston Public Housing
Authors: Brod Michael , Cedeño Laurent José Guillermo , Kane John , Colton Meryl D. , Gabel Charlotte , Adamkiewicz Gary
Published: March 2020

The Boston Residential Investigation on Green and Healthy Transitions (BRIGHT) Study is focused on quantifying the effects of redeveloping public housing developments into new buildings with improved energy performance and indoor environmental quality. This report presents an analysis of utility consumption and work order requests at Old Colony and Washington-Beech, two redeveloped housing sites in Boston, Massachusetts. We compare the consumption of electricity, natural gas, and water, as well as work order data, from 2012–2014 to development-wide baseline data from 2006–2009. We found that despite the higher number of electric appliances in the new apartments (e.g., air conditioning and ranges), electricity consumption decreased 46% in Old Colony and nearly 30% in Washington-Beech when compared to the baseline data. Natural gas used for space heating decreased by more than 70% at both sites; and water use decreased by nearly 56% at Old Colony and nearly 30% at Washington-Beech. Work order categories that directly influence the residents’ quality of life, such as pests, mold, windows and plumbing decreased by more than 50% in both renovated sites. In combination with previous documentation of health improvements in the redeveloped sites, these results provide further evidence of the magnitude of benefits from updating public housing infrastructure using green design principles.
Innovative Trend Analysis of Precipitation in the Lake Issyk-Kul Basin, Kyrgyzstan
Authors: Alifujiang Yilinuer , Abuduwaili Jilili , Maihemuti Balati , Emin Bilal , Groll Michael
Published: March 2020

The analysis of various characteristics and trends of precipitation is an essential task to improve the utilization of water resources. Lake Issyk-Kul basin is an upper alpine catchment, which is more susceptible to the effects of climate variability, and identifying rainfall variations has vital importance for water resource planning and management in the lake basin. The well-known approaches linear regression, Şen’s slope, Spearman’s rho, and Mann-Kendall trend tests are applied frequently to try to identify trend variations, especially in rainfall, in most literature around the world. Recently, a newly developed method of Şen-innovative trend analysis (ITA) provides some advantages of visual-graphical illustrations and the identification of trends, which is one of the main focuses in this article. This study obtained the monthly precipitation data (between 1951 and 2012) from three meteorological stations (Balykchy, Cholpon-Ata, and Kyzyl-Suu) surrounding the Lake Issyk-Kul, and investigated the trends of precipitation variability by applying the ITA method. For comparison purposes, the traditional Mann–Kendall trend test also used the same time series. The main results of this study include the following. (1) According to the Mann-Kendall trend test, the precipitation of all months at the Balykchy station showed a positive trend (except in January (Zc = −0.784) and July (Zc = 0.079)). At the Cholpon-Ata and Kyzyl-Suu stations, monthly precipitation (with the same month of multiple years averaged) indicated a decreasing trend in January, June, August, and November. At the monthly scale, significant increasing trends (Zc > Z0.10 = 1.645) were detected in February and October for three stations. (2) The ITA method indicated that the rising trends were seen in 16 out of 36 months at the three stations, while six months showed decreasing patterns for “high” monthly precipitation. According to the “low” monthly precipitations, 14 months had an increasing trend, and four months showed a decreasing trend. Through the application of the ITA method (January, March, and August at Balykchy; December at Cholpon-Ata; and July and December at Kyzyl-Suu), there were some significant increasing trends, but the Mann-Kendall test found no significant trends. The significant trend occupies 19.4% in the Mann-Kendall test and 36.1% in the ITA method, which indicates that the ITA method displays more positive significant trends than Mann–Kendall Zc. (3) Compared with the classical Mann-Kendall trend results, the ITA method has some advantages. This approach allows more detailed interpretations about trend detection, which has benefits for identifying hidden variation trends of precipitation and the graphical illustration of the trend variability of extreme events, such as “high” and “low” values of monthly precipitation. In contrast, these cannot be discovered by applying traditional methods.
Long-Term Characterization of Submicron Atmospheric Particles in an Urban Background Site in Southern Italy
Authors: Dinoi Adelaide , Conte Marianna , Grasso Fabio M. , Contini Daniele
Published: March 2020

Continuous measurements of particle number size distributions in the size range from 10 nm to 800 nm were performed from 2015 to 2019 at the ECO Environmental-Climate Observatory of Lecce (Global Atmosphere Watch Programme/Aerosol, Clouds and Trace Gases Research Infrastructure (GAW/ACTRIS) regional station). The main objectives of this work were to investigate the daily, weekly and seasonal trends of particle number concentrations and their dependence on meteorological parameters gathering information on potential sources. The highest total number concentrations were observed during autumn-winter with average values nearly twice as high as in summer. More than 52% of total particle number concentration consisted of Aitken mode (20 nm < particle diameter (Dp) < 100 nm) particles followed by accumulation (100 nm < Dp < 800 nm) and nucleation (10 nm < Dp < 20 nm) modes representing, respectively, 27% and 21% of particles. The total number concentration was usually significantly higher during workdays than during weekends/holidays in all years, showing a trend likely correlated with local traffic activities. The number concentration of each particle mode showed a characteristic daily variation that was different in cold and warm seasons. The highest concentrations of the Aitken and accumulation particle mode were observed in the morning and the late evening, during typical rush hour traffic times, highlighting that the two-particle size ranges are related, although there was significant variation in the number concentrations. The peak in the number concentrations of the nucleation mode observed in the midday of spring and summer can be attributed to the intensive formation of new particles from gaseous precursors. Based on Pearson coefficients between particle number concentrations and meteorological parameters, temperature, and wind speed had significant negative relationships with the Aitken and accumulation particle number concentrations, whereas relative humidity was positively correlated. No significant correlations were found for the nucleation particle number concentrations.
Modeling Land Suitability for Vitis vinifera in Michigan Using Advanced Geospatial Data and Methods
Authors: Wanyama Dan , Bunting Erin L. , Goodwin Robert , Weil Nicholas , Sabbatini Paolo , Andresen Jeffrey A.
Published: March 2020

Michigan (MI) has a long history of diverse agricultural production. One of the most rapidly expanding and profitable agricultural crops, wine grapes (Vitis vinifera L.), has only been in cultivation across MI since the 1970s. As of 2014 more than 2100 acres of Vitis vinifera were growing statewide. With such success there is a push to rapidly develop more vinifera vineyards across the state. The industry is striving to have 10,000 acres in cultivation by 2024. This study presents a data-driven approach for guiding decision making to make this goal attainable. The study models land suitability across the state using environmental, climate, topographic and land use data to understand the most to least ideal portions of the landscape for vinifera establishment. The models are tested in 17 MI counties. The study found that land suitability for viticulture has expanded and therefore, viticulture can be extended beyond the traditional growing areas. This study suggests that warming temperatures have influenced land suitability and demonstrates the application and utility of GIS-based land suitability modeling in viticulture development. Maps produced in this study provide knowledge of the climate and environmental trends, which is critical when choosing where and what cultivar to grow. With such resources, growers can be better prepared to invest and expand this pivotal agricultural sector.
Using Satellite Data to Determine Empirical Relationships between Volcanic Ash Source Parameters
Authors: Zidikheri Meelis J. , Lucas Chris
Published: March 2020

Poor knowledge of dispersion model source parameters related to quantities such as the total fine ash mass emission rate, its effective spatial distribution, and particle size distribution makes the provision of quantitative forecasts of volcanic ash a difficult problem. To ameliorate this problem, we make use of satellite-retrieved mass load data from 14 eruption case studies to estimate fine ash mass emission rates and other source parameters by an inverse modelling procedure, which requires multidimensional sampling of several thousand trial simulations with different values of source parameters. We then estimate the dependence of these optimal source parameters on eruption height. We show that using these empirical relationships in a data assimilation procedure leads to substantial improvements to the forecasts of ash mass loads, with the use of empirical relationships between parameters and eruption height having the added advantage of computational efficiency because of dimensional reduction. In addition, the use of empirical relationships, which encode information in satellite retrievals from past case studies, implies that quantitative forecasts can still be issued even when satellite retrievals of mass load are not available in real time due to cloud cover or other reasons, making it especially useful for operations in the tropics where ice and water clouds are ubiquitous.
Simulating Real Atmospheric Boundary Layers at Gray-Zone Resolutions: How Do Currently Available Turbulence Parameterizations Perform?
Authors: Doubrawa Paula , Muñoz-Esparza Domingo
Published: March 2020

Recent computational and modeling advances have led a diverse modeling community to experiment with atmospheric boundary layer (ABL) simulations at subkilometer horizontal scales. Accurately parameterizing turbulence at these scales is a complex problem. The modeling solutions proposed to date are still in the development phase and remain largely unvalidated. This work assesses the performance of methods currently available in the Weather Research and Forecasting (WRF) model to represent ABL turbulence at a gray-zone grid spacing of 333 m. We consider three one-dimensional boundary layer parameterizations (MYNN, YSU and Shin-Hong) and coarse large-eddy simulations (LES). The reference dataset consists of five real-case simulations performed with WRF-LES nested down to 25 m. Results reveal that users should refrain from coarse LES and favor the scale-aware, Shin-Hong parameterization over traditional one-dimensional schemes. Overall, the spread in model performance is large for the cellular convection regime corresponding to the majority of our cases, with coarse LES overestimating turbulent energy across scales and YSU underestimating it and failing to reproduce its horizontal structure. Despite yielding the best results, the Shin-Hong scheme overestimates the effect of grid dependence on turbulent transport, highlighting the outstanding need for improved solutions to seamlessly parameterize turbulence across scales.
Analyzing Trend and Variability of Rainfall in The Tafna Basin (Northwestern Algeria)
Authors: Bougara Hanane , Hamed Kamila Baba , Borgemeister Christian , Tischbein Bernhard , Kumar Navneet
Published: March 2020

Northwest Algeria has experienced fluctuations in rainfall between the two decades 1940s and 1990s from positive to negative anomalies, which reflected a significant decline in rainfall during the mid-1970s. Therefore, further analyzing rainfall in this region is required for improving the strategies on water resource management. In this study, we complement previous studies by dealing with sub basins that were not previously addressed in Tafna basin (our study area located in Northwest Algeria), and by including additional statistical methods (Kruskal–Wallis test, Jonckheere-Terpstra test, and the Friedman test) that were not earlier reported on the large scale (Northwest Algeria). In order to analyse the homogeneity, trends, and stationarity in rainfall time series for nine rainfall stations over the period 1979–2011, we have used several statistical tests. The results showed an increasing trend for annual rainfall after the break detected in 2007 for Djbel Chouachi, Ouled Mimoun, Sidi Benkhala stations using Hubert, Pettitt, and Buishand tests. The Lee and Heghinian test has detected a break at the same year in 2007 for all stations except Sebdou, Beni Bahdel, and Hennaya stations, which have a break date in 1980. We have confirmed this increasing trend for rainfall with other trend detection methods such as Mann Kendall and Sen’s method that highlighted an upward trend for all the stations in the autumn season, which is mainly due to an increase in rainfall in September and October. On a monthly scale, the date of rupture is different from one station to another because the time series are not homogeneous. In addition, we have applied three tests enabling further results: (i) the Jonckheere-Terpstra test has detected an upward trend for two stations (Khemis and Hennaya), (ii) Friedman test has indicated the difference between the mean rank again with Khemis and Hennaya stations and the Merbeh station, (iii) according to the Kruskal-Wallis test, there have been no variance detected between all the rainfall stations. The increasing trend in rainfall may lead to a rise in stream flow and enhance potential floods risks in low-lying regions of the study area.
Phylogenetic Analyses of Sites in Different Protein Structural Environments Result in Distinct Placements of the Metazoan Root
Authors: Pandey Akanksha , Braun Edward L.
Published: March 2020

Phylogenomics, the use of large datasets to examine phylogeny, has revolutionized the study of evolutionary relationships. However, genome-scale data have not been able to resolve all relationships in the tree of life; this could reflect, at least in part, the poor-fit of the models used to analyze heterogeneous datasets. Some of the heterogeneity may reflect the different patterns of selection on proteins based on their structures. To test that hypothesis, we developed a pipeline to divide phylogenomic protein datasets into subsets based on secondary structure and relative solvent accessibility. We then tested whether amino acids in different structural environments had distinct signals for the topology of the deepest branches in the metazoan tree. We focused on a dataset that appeared to have a mixture of signals and we found that the most striking difference in phylogenetic signal reflected relative solvent accessibility. Analyses of exposed sites (residues located on the surface of proteins) yielded a tree that placed ctenophores sister to all other animals whereas sites buried inside proteins yielded a tree with a sponge+ctenophore clade. These differences in phylogenetic signal were not ameliorated when we conducted analyses using a set of maximum-likelihood profile mixture models. These models are very similar to the Bayesian CAT model, which has been used in many analyses of deep metazoan phylogeny. In contrast, analyses conducted after recoding amino acids to limit the impact of deviations from compositional stationarity increased the congruence in the estimates of phylogeny for exposed and buried sites; after recoding amino acid trees estimated using the exposed and buried site both supported placement of ctenophores sister to all other animals. Although the central conclusion of our analyses is that sites in different structural environments yield distinct trees when analyzed using models of protein evolution, our amino acid recoding analyses also have implications for metazoan evolution. Specifically, our results add to the evidence that ctenophores are the sister group of all other animals and they further suggest that the placozoa+cnidaria clade found in some other studies deserves more attention. Taken as a whole, these results provide striking evidence that it is necessary to achieve a better understanding of the constraints due to protein structure to improve phylogenetic estimation.
Competitive HRP-Linked Colorimetric Aptasensor for the Detection of Fumonisin B1 in Food based on Dual Biotin-Streptavidin Interaction
Authors: Tao Zui , Zhou You , Li Xiang , Wang Zhouping
Published: March 2020

Fumonisin B1 (FB1) is the most prevalent and toxic form among fumonisin homologues which are produced by fusarium species and it contaminates various types of food products, posing serious health hazards for humans and animals. In this work, a colorimetric assay for the detection of FB1 has been developed based on competitive horseradish peroxidase (HRP)-linked aptamer and dual biotin-streptavidin interaction. In short, a biotinylated aptamer of FB1 was immobilized on the microplate by biotin-streptavidin binding; the complementary strand (csDNA) of the aptamer was ligated with HRP by biotin-streptavidin binding again to form a csDNA-HRP sensing probe, competing with FB1 to bind to the aptamer. The color change can be observed after the addition of chromogenic and stop solution, thereby realizing the visual detection of FB1. Under optimal conditions, good linearity was observed within the concentration range of 0.5 to 300 ng/mL, with a detection of limit of 0.3 ng/mL. This assay is further validated by spike recovery tests towards beer and corn samples, it provides a simple, sensitive and reliable method for the screening of FB1 in food samples and may be potentially used as an alternative to conventional assays.
EEG Theta Power Activity Reflects Workload among Army Combat Drivers: An Experimental Study
Authors: Diaz-Piedra Carolina , Sebastián María Victoria , Di Stasi Leandro L.
Published: March 2020

We aimed to evaluate the effects of mental workload variations, as a function of the road environment, on the brain activity of army drivers performing combat and non-combat scenarios in a light multirole vehicle dynamic simulator. Forty-one non-commissioned officers completed three standardized driving exercises with different terrain complexities (low, medium, and high) while we recorded their electroencephalographic (EEG) activity. We focused on variations in the theta EEG power spectrum, a well-known index of mental workload. We also assessed performance and subjective ratings of task load. The theta EEG power spectrum in the frontal, temporal, and occipital areas were higher during the most complex scenarios. Performance (number of engine stops) and subjective data supported these findings. Our findings strengthen previous results found in civilians on the relationship between driver mental workload and the theta EEG power spectrum. This suggests that EEG activity can give relevant insight into mental workload variations in an objective, unbiased fashion, even during real training and/or operations. The continuous monitoring of the warfighter not only allows instantaneous detection of over/underload but also might provide online feedback to the system (either automated equipment or the crew) to take countermeasures and prevent fatal errors.
Chemosensory Event-Related Potentials and Power Spectrum Could Be a Possible Biomarker in 3M Syndrome Infants?
Authors: Invitto Sara , Grasso Alberto , Lofrumento Dario Domenico , Ciccarese Vincenzo , Paladini Angela , Paladini Pasquale , Marulli Raffaella , De Pascalis Vilfredo , Polsinelli Matteo , Placidi Giuseppe
Published: March 2020

3M syndrome is a rare disorder that involves the gene cullin-7 (CUL7). CUL7 modulates odour detection, conditions the olfactory response (OR) and plays a role in the development of the olfactory system. Despite this involvement, there are no direct studies on olfactory functional effects in 3M syndrome. The purpose of the present work was to analyse the cortical OR through chemosensory event-related potentials (CSERPs) and power spectra calculated by electroencephalogram (EEG) signals recorded in 3M infants: two twins (3M-N) and an additional subject (3M-O). The results suggest that olfactory processing is diversified. Comparison of N1 and Late Positive Component (LPC) indicated substantial differences in 3M syndrome that may be a consequence of a modified olfactory processing pattern. Moreover, the presence of delta rhythms in 3M-O and 3M-N clearly indicates their involvement with OR, since the delta rhythm is closely connected to chemosensory perception, in particular to olfactory perception.
Construction History and the History of Construction Cultures: Between Architecture and Engineering in Portugal
Authors: Mascarenhas-Mateus João
Published: March 2020

This paper aims to debate the epistemological boundaries of construction history, in relation to the fields of history of architecture and the history of engineering, using Portugal as a case study. The concept of construction culture is used to broaden the analysis, avoiding the old dichotomy between architects and engineers. Instead, construction history (understood as the history of construction cultures) aims to integrate the contributions of all actors in this sector of activity, such as contractors, materials and machine producers, traders, and public and private institutions. The history of architecture and the history of engineering in Portugal serves to illustrate the extent to which the study of how a community built in a particular space, at a particular time, is fragmented in the present age. The conclusions highlight the limits of a history that has been interpreted mainly from the point of view of the activity of architects and engineers. This paper also explores the potential of a history of construction cultures as a constructum in constant transition and under constant discussion, capable of explaining the set of problems involved in this millennia-old human activity.
Old Dumped Fly Ash as a Sand Replacement in Cement Composites
Authors: Harasymiuk Jolanta , Rudziński Andrzej
Published: March 2020

The use of industrial residues to replace natural resources for the production of building materials is economically and ecologically justified. Fly ash (FA) taken directly from electro-filters is commonly used as a cement replacement material. This is not the case, however, for old dumped fly ash (ODFA) that has been accumulating in on-site waste dumps for decades and currently has no practical use. It causes environmental degradation, which is not fully controlled by the governments of developed countries. The aim of the study was to assess the possibility of using ODFA as a partial replacement for sand in cement composites. ODFA replaced part of the sand mass (20% and 30%) in composites with a limited amount of cement (a cement-saving measure) and sand (saving non-renewable raw material resources). ODFA was activated by the addition of different proportions of hydrated lime, the purposes of which was to trigger a pozzolanic reaction in ODFA. The quantitative composition of the samples was chosen in such a way as to ensure the maximum durability and longevity of composites with a limited amount of cement. The 28-day samples were exposed to seawater attack for 120 days. After this period, the compressive strength of each sample series was determined. The results suggest the possibility of using ODFA with hydrated lime to lay town district road foundations and bike paths of 3.5 to 5 MPA compressive strength. What is more, these composites can be used in very aggressive environments.
Explaining Bamboo-Like Carbon Fiber Growth Mechanism: Catalyst Shape Adjustments above Tammann Temperature
Authors: Lobo Luís Sousa , Carabineiro Sónia A.C.
Published: March 2020

The mechanism of bamboo-like growth behavior of carbon fibers is discussed. We propose that there is a requirement to have this type of growth: operation above the Tammann temperature of the catalyst (defined as half of the melting point). The metal nanoparticle shape can then change during reaction (sintering-like behavior) facilitating carbon nanotube (CNT) growth, adjusting geometry. Using metal nanoparticles with a diameter below 20 nm, some reduction of the melting point (mp) and Tammann temperature (TTa) is observed. Fick’s laws still apply at nano scale. In that range, distances are short and so bulk diffusion of carbon (C) atoms through metal nanoparticles is quick. Growth occurs under catalytic and hybrid carbon formation routes. Better knowledge of the mechanism is an important basis to optimize growth rates and the shape of bamboo-like C fibers. Bamboo-like growth, occurring under pyrolytic carbon formation, is excluded: the nano-catalyst surface in contact with the gas gets quickly “poisoned”, covered by graphene layers. The bamboo-like growth of boron nitride (BN) nanotubes is also briefly discussed.
Atom-economical Synthesis and Characterization of Poly(oxindolidene thienylene vinylene) Based on Aldol Polycondensation Reaction
Authors: Sato Shingo , Lin Po-Shen , Wu Wei-Ni , Liu Cheng-Liang , Higashihara Tomoya
Published: March 2020

It is known that π-conjugated polymers can be easily synthesized using monomers which possess metals or halogen atoms as well as transition-metal catalysts. However, in the polymer materials synthesized by such reactions, small amounts of halogens and transition-metal-catalysts remain, often negatively affecting their optoelectronic device performances. Herein, we report a new polycondensation method based on the aldol condensation reaction utilizing the intramolecular resonance effect of the anionic monomer through π-conjugation. We have designed a novel AB type monomer to synthesize the semiconducting poly(oxindolidene thienylene vinylene) (POTV) using the proposed system. Indeed, the polymerization readily proceeded by adding 5-nitro-2-thiophenecarbaldehyde as an initiator after the α-proton abstraction of the oxindole group by the reaction of the monomer precursor with lithium hexamethylsilazide (LiHMDS)/12-crown-4. As a result, the objective POTV with Mn = 3700 and ÐM = 1.47 could be obtained with a good yield (65%). In addition, an organic field effect transistor (OFET) was based on POTV exhibited p-type characteristics, with a hole mobility of 2.24 × 10−4 cm2 V−1 s−1.
Congo Red Dye Degradation by Graphene Nanoplatelets/Doped Bismuth Ferrite Nanoparticle Hybrid Catalysts under Dark and Light Conditions
Authors: Fatima Sabeen , Ali S. Irfan , Iqbal Muhammad Z. , Rizwan Syed
Published: March 2020

The continuously growing need for clean water has increased research looking for new and efficient ways to treat wastewater. Due to its magnetic properties, Bismuth ferrite, a photo-catalyst, has introduced a novel field of photo-catalysis where the photo-catalytic material could easily be separated from the aqueous solution after wastewater treatment. Herein, a new type of photo-catalysts, composed of Gadolinium (Gd) and Tin (Sn), co-doped Bismuth Ferrite deposited over graphene nanoplatelet surface have been synthesized using a two-step method. In first step, Gd (fixed concentration 10%) and Sn (5%, 15%, 20% and 25%) were doped inside bismuth ferrite (BFO) host using sol-gel method (namely the BGFSO nanoparticles, abbreviated for Gd and Sn doped BFO). In the second step, BGFSO nanoparticles were introduced onto GNPs using co-precipitation method (namely the BGFSO/GNP nanohybrids). The x-ray photoelectron spectroscopy confirmed the chemical bonding between co-doped BFO and GNP sheets via oxy and hydroxyl groups. The photocatalytic activities of the nanohybrids under both, visible light and dark conditions have been increased, and the maximum degradation activity (74%) of organic dye Congo-red (CR) is obtained for 25% Sn-doped BGFSO/GNP nanohybrid. The photocatalytic activity may be attributed to enhanced adsorption capability, electron storage properties of graphene and the presence of oxygen-rich species inside nanohybrids. Based on the current overgrowing population and need for clean water, these materials present versatile potential as catalysts for wastewater treatment.
Suzuki–Miyaura Cross-Coupling of Amides Using Well-Defined, Air- and Moisture-Stable Nickel/NHC (NHC = N-Heterocyclic Carbene) Complexes
Authors: Buchspies Jonathan , Rahman Md. Mahbubur , Szostak Michal
Published: March 2020

In this Special Issue on N-Heterocyclic Carbenes and Their Complexes in Catalysis, we report the first example of Suzuki–Miyaura cross-coupling of amides catalyzed by well-defined, air- and moisture-stable nickel/NHC (NHC = N-heterocyclic carbene) complexes. The selective amide bond N–C(O) activation is achieved by half-sandwich, cyclopentadienyl [CpNi(NHC)Cl] complexes. The following order of reactivity of NHC ligands has been found: IPr > IMes > IPaul ≈ IPr*. Both the neutral and the cationic complexes are efficient catalysts for the Suzuki–Miyaura cross-coupling of amides. Kinetic studies demonstrate that the reactions are complete in < 1 h at 80 °C. Complete selectivity for the cleavage of exocyclic N-acyl bond has been observed under the experimental conditions. Given the utility of nickel catalysis in activating unreactive bonds, we believe that well-defined and bench-stable [CpNi(NHC)Cl] complexes will find broad application in amide bond and related cross-couplings of bench-stable acyl-electrophiles.
Highly Dispersed Pt Nanoparticles on N-Doped Ordered Mesoporous Carbon as Effective Catalysts for Selective Hydrogenation of Nitroarenes
Authors: Sheng Yao , Lin Xinrui , Wang Xueguang , Zou Xiujing , Zhang Chunlei
Published: March 2020

Highly-dispersed Pt nanoparticles supported on nitrogen-modified CMK-3 mesoporous carbon (Pt/N-CMK-3) were first fabricated by a two-step impregnation route. The influences of N content on the catalyst porous structure, Pt nanoparticle size, surface properties, and interaction between Pt species and the support were investigated in detail using N2 sorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectra (XPS). The N species acted as anchoring sites for the stabilization of Pt particles. Benefiting from the formation of ultrafine metal nanoparticles, the Pt/N-CMK-3 exhibited excellent catalytic activity and selectivity for the selective hydrogenation of nitro aromatics to the corresponding anilines with hydrogen. The Pt/N-CMK-3 catalyst could be reused eight times and keep its catalytic performance.
Assessment of Climate Change Impacts on Sea Surface Temperatures and Sea Level Rise—The Arabian Gulf
Authors: Hereher Mohamed E.
Published: March 2020

The Arabian Gulf is one of the regions in the world experiencing major changes due to increased economic growth rates and development practices. As a shallow water body within a hot desert, the Gulf is exposed to obvious warming in the sea surface temperatures (SST). Remotely sensed SST data were utilized to estimate decadal change in SST with a focus on coral reef locations. There is a positive trend in monthly time series SSTs, with a maximum value of about 0.7 °C/decade for the western side of the Gulf. This high trend of SST is associated with significant coral reef bleaching and it coincides with major climate/ocean interactions. Most of the Arabian countries along the Gulf have coastal developments at low-land areas of high vulnerability to sea level rise. Digital elevation models showed that there are more than 3100 km2 of coastal areas that occur at 1 m level along the Arabian countries of the Gulf. Coastal protection and conservation measures are crucial to protect low-lying coasts of urban use.
Room and High Temperature Tribological Behaviour of W-DLC Coatings Produced by DCMS and Hybrid DCMS-HiPIMS Configuration
Authors: Evaristo Manuel , Fernandes Filipe , Cavaleiro Albano
Published: March 2020

Carbon-based coatings are used in many applications, particularly in sliding contacts to reduce friction and wear. To improve the tribological properties, these coatings are usually alloyed with metals; W is one of the most used since it helps improve the tribological performance at high temperatures. In this work, we compared the tribological performance of Diamond-Like Carbon alloyed with tungsten (DLC-W) films deposited by direct current magnetron sputtering (DCMS) with films deposited in a hybrid configuration DCMS + high power impulse magnetron sputtering (HiPIMS). The DLC-W coatings were produced with approximately the same W content. One hydrogenated film was deposited with the hybrid configuration for comparison purposes. Microstructure, structure, mechanical properties, and tribological behaviour were used to compare the coatings. All the films displayed a low-order structure of tungsten carbide embedded in an amorphous carbon matrix. The use of the hybrid HiPIMS/DCMS results in coatings with more compact morphologies due to the high ionization fraction of the species produced on the W target (W and Ar ionized species), which primarily will oppose the shadowing effect as the ions will reach the substrate at angles close to 90°. HiPIMS non-hydrogenated film is the more tribological, performing either at room or high temperature (150 °C) due to the much more compact morphology, which avoids the detachment of hard W-C particles, which are responsible for more efficiently scratching the film surface. Experiments revealed that wear behaviour in all the films is governed by the contact of the tribolayer formed on the counterpart composed of W–C, C and W–O against the surface of the film.
Antibacterial Efficiency of Stainless-Steel Grids Coated with Cu-Ag by Thermionic Vacuum Arc Method
Authors: Dinca P. , Butoi B. , Lungu M. , Porosnicu C. , Jepu I. , Staicu C. , Lungu C.P. , Niculescu A. , Burducea I. , Trusca O. , Diaconu M. , Cretescu I. , Soreanu G.
Published: March 2020

Autonomous smart natural ventilation systems (SVS) attached to the glass façade of living quarters and office buildings can help reducing the carbon footprint of city buildings in the future, especially during warm seasons and can represent an alternative to the conventional mechanical ventilation systems. The work performed in this manuscript focuses on the investigation of bacteria trapping and killing efficiency of stainless steel grids coated with a mixed layer of Cu-Ag. These grids are to be employed as decontamination filters for a smart natural ventilation prototype that we are currently building in our laboratory. The tested grids were coated with a mixed Cu-Ag layer using thermionic vacuum arc plasma processing technology. The fixed deposition geometry allowed the variation of Cu and Ag atomic concentration in coated layers as a function of substrate position in relation to plasma sources. The test conducted with air contaminated with a pathogen strain of staphylococcus aureus indicated that the filtering efficiency is influenced by two parameters: the pore size dimension and the coating layer composition. The results show that the highest filtering efficiency of 100% was obtained for fine pore (0.5 × 0.5 mm) grids coated with a mixed metallic layer composed of 65 at% Cu and 35 at% Ag. The second test performed only on reference grids and Cu-Ag (65–35 at%) under working conditions, confirm a similar filtering efficiency for the relevant microbiological markers. This particular sample was investigated from morphological, structural, and compositional point of view. The results show that the layer has a high surface roughness with good wear resistance and adhesion to the substrate. The depth profiles presented a uniform composition of Cu and Ag in the layer with small variations caused by changes in deposition rates during the coating process. Identification of the two metallic phases of the Cu and Ag in the layers evidences their crystalline nature. The calculated grain size of the nanocrystalline was in the range 14–21 nm.
Edible Films Based on Black Chia (Salvia hispanica L.) Seed Mucilage Containing Rhus microphylla Fruit Phenolic Extract
Authors: Charles-Rodríguez Ana V. , Rivera-Solís Luz L. , Martins Joana T. , Genisheva Zlatina , Robledo-Olivo Armando , González-Morales Susana , López-Guarin Gustavo , Martínez-Vázquez Dolores G. , Vicente António A. , Flores-López María L.
Published: March 2020

Functional films based on black chia (Salvia hispanica L.) seed mucilage (BCm) containing Rhus microphylla (Rm) fruit phenolic extract were built and characterized. A hydro-alcohol extract (HAE) of Rm was incorporated as the bioactive agent due to its noteworthy phenolic profile, and good antioxidant and antifungal activities. The effects of the BCm concentration (0.2% and 0.4%, w/v), HAE incorporation, and their interaction with glycerol (1.0%, w/v) and calcium chloride (0.05%, w/v) on the films’ physicochemical properties were evaluated. The filmogenic solutions successfully fitted to the Herschel–Bulkley model (R2 < 0.999), exhibiting a pseudoplastic and shear thinning character, typical of polymer solutions. Interestingly, their rheological properties were not (p > 0.05) changed by the HAE addition, but their surface tension was enhanced (p < 0.05), which could favor their coating ability. The polyanionic nature of the systems (zeta potential-Zp values from −26.9 to −33.3 mV) allowed them to interact with Ca2+ cations, thus forming stable and resistant films. All the films showed low water solubility (15.0% to 22.3%) and high permeability (3.7 to 4.0 × 10−10 g m−1 s−1 Pa−1), as well as high biodegradability (moisture content from 66.0% to 80.9%); although the moisture content was reduced (p < 0.05) with HAE addition. The combination of higher BCm ratio and HAE addition (BCm0.4+Rm) led to a more resistant, thick, opaque, and dark film compared with the others obtained. This study reveals the BCm-based films’ potential, highlighting those with HAE, representing a novel alternative to improve the quality of food products.
On the Mechanism of Formation of Conversion Titanium-Containing Coatings
Authors: Abrashov Aleksey , Grigoryan Nelya , Vagramyan Tigran , Asnis Naum
Published: March 2020

The present work is devoted to the study of the mechanism of the process of formation of adhesive oxide-titanium coatings on steel, zinc, and aluminum surfaces. For the first time, the following hypothesis has been confirmed experimentally, namely, that nickel, being the first metal to be deposited on a steel substrate, creates active centers on which titanium oxides are formed, because the hydrolysis of hexafluorotitanic acid is adsorbed, which then form a continuous film. The data obtained, regarding the dependence of the coating thickness on the linear rate of the solution flow along the treated surface, indirectly confirm that the formation of insoluble titanium oxides occurs because of the alkalization of the solution adjacent to the surface. It has been established that in the presence of hexavalent molybdenum compounds in the solution as oxidizers, molybdenum is included in the coating in the form of oxides. It has been revealed that in the lower layers of the coating, molybdenum is contained in the form of compounds of molybdenum (V) and (VI), while in the upper layers, it is contained only in the form of the compound of molybdenum (VI).
Investigating the Thermo-Mechanical Behavior of a Ceramic Matrix Composite Wing Leading Edge by Sub-Modeling Based Numerical Analyses
Authors: Ferraiuolo Michele , Palumbo Concetta , Sellitto Andrea , Riccio Aniello
Published: March 2020

The thermo-structural design of the wing leading edge of hypersonic vehicles is a very challenging task as high gradients in thermal field, and hence high thermal stresses, are expected. Indeed, when employing passive hot structures based thermal protection systems, very high temperatures (e.g., 1400 °C) are expected on the external surface of the wing leading edge, while the internal structural components are required to not exceed a few hundred degrees Celsius (e.g., 400 °C) at the interface with the internal cold structure. Hence, ceramic matrix composites (CMC) are usually adopted for the manufacturing of the external surface of the wing leading edge since they are characterized by good mechanical properties at very high temperatures (up to 1900 °C) together with an excellent thermal shock resistance. Furthermore, the orthotropic behavior of these materials together with the possibility to tailor their lamination sequence to minimize the heat transferred to internal components, make them very attractive for hot structure based thermal protection systems applications. However, the numerical predictions of the thermo-mechanical behavior of such materials, taking into account the influence of each ply (whose thickness generally ranges between 0.2 and 0.3 mm), can be very expensive from a computational point of view. To overcome this limitation, usually, sub-models are adopted, able to focus on specific and critical areas of the structure where very detailed thermo-mechanical analyses can be performed without significantly affecting the computational efficiency of the global model. In the present work, sub-modeling numerical approaches have been adopted for the analysis of the thermo-mechanical behavior of a ceramic matrix composite wing leading edge of a hypersonic vehicle. The main aim is to investigate the feasibility, in terms of computational efficiency and accuracy of results, in using sub-models for dimensioning complex ceramic matrix components. Hence, a comprehensive study on the size of sub-models and on the choice of their boundaries has been carried out in order to assess the advantages and the limitations in approximating the thermo-mechanical behavior of the investigated global ceramic matrix composite component.
Accelerating Surface Tension Calculation in SPH via Particle Classification and Monte Carlo Integration
Authors: Zorilla Fernando , Ritter Marcel , Sappl Johannes , Rauch Wolfgang , Harders Matthias
Published: March 2020

Surface tension has a strong influence on the shape of fluid interfaces. We propose a method to calculate the corresponding forces efficiently. In contrast to several previous approaches, we discriminate to this end between surface and non-surface SPH particles. Our method effectively smooths the fluid interface, minimizing its curvature. We make use of an approach inspired by Monte Carlo integration to estimate local normals as well as curvatures, based on which the force can be calculated. We compare different sampling schemes for the Monte Carlo approach, for which a Halton sequence performed best. Our overall technique is applicable, but not limited to 2D and 3D simulations, and can be coupled with any common SPH formulation. It outperforms prior approaches with regard to total computation time per time step in dynamic scenes. Additionally, it is adjustable for higher quality in small scale scenes with dominant surface tension effects.
A Multi-Hop Data Dissemination Algorithm for Vehicular Communication
Authors: Urmonov Odilbek , Kim HyungWon
Published: March 2020

In vehicular networks, efficient multi-hop message dissemination can be used for various purposes, such a informing the driver about the recent emergency event or propagating the local dynamic map of a predefined region. Dissemination of warning information up to a longer distance can reduce the accidents on the road. It provides a driver additional time to react to the situations adequately and assists in finding a safe route towards the destination. The adopted V2X standards, ETSI TS’s C-ITS and IEEE 1609/IEEE 802.11p, specify only primitive multi-hop message dissemination schemes. IEEE 1609.4 standard disseminates the broadcast messages using the method of flooding, which causes high redundancy, severe congestion, and long delay during multi-hop propagation. To address these problems, we propose an effective broadcast message dissemination method. It introduces a notion of source Lateral Crossing Line (LCL) algorithm, which elects a set of relay vehicles for each hop based on the vehicle locations in a way that reduces the redundant retransmission and congestion, consequently minimizing the delays. Our simulation results demonstrated that the proposed method can achieve about 15% reduction in delays and 2 times the enhancement in propagation distance compared with the previous methods.
Investigation of the Structural Changes and Catalytic Properties of FeNi Nanostructures as a Result of Exposure to Gamma Radiation
Authors: Borgekov Daryn B. , Zdorovets Maxim V. , Shlimas Dmitriy I. , Kozlovskiy Artem L.
Published: March 2020

The paper presents the results of changes in the structural characteristics, and the degree of texturing of FeNi nanostructures close in composition to permalloy compounds as a result of directed modification by gamma radiation with an energy of 1.35 MeV and doses from 100 to 500 kGy. The choices of energy and radiation doses were due to the need to modify the structural properties, which consisted of annealing the point defects that occurred during the synthesis along the entire length of the nanotubes. The initial FeNi nanostructures were polycrystalline nanotubes of anisotropic crystallite orientation, obtained by electrochemical deposition. The study found that exposure to gamma rays led to fewer defects in the structure, and reorientation of crystallites, and at doses above 300 kGy, the presence of one selected texture direction (111) in the structure. During tests of the corrosion resistance of synthesized and modified nanostructures in a PBS solution at various temperatures, it was found that exposure to gamma rays led to a significant decrease in the rate of degradation of nanotubes and an increase in the potential life of up to 20 days. It was established that at the first stage of testing, the degradation of nanostructures is accompanied by the formation of oxide inclusions, which subsequently lead to the formation of pitting corrosion and subsequent partial or complete destruction of the nanostructures. It is shown that gamma radiation is promising not only for targeted modification of nanostructures and increasing resistance to degradation, but also for increasing the rate of catalytic reactions of the PNA-PPD type.