Spatio-temporal interpolation of daily temperatures for global land areas at 1 km resolution

Combined Global Surface Summary of Day and European Climate Assessment and Dataset daily meteorological data sets (around 9000 stations) were used to build spatio-temporal geostatistical models and predict daily air temperature at ground resolution of 1km for the global land mass. Predictions in space and time were made for the mean, maximum, and minimum temperatures using spatio-temporal regression-kriging with a time series of Moderate Resolution Imaging Spectroradiometer (MODIS) 8 day images, topographic layers (digital elevation model and topographic wetness index), and a geometric temperature trend as covariates. The accuracy of predicting daily temperatures was assessed using leave-one-out cross validation. To account for geographical point clustering of station data and get a more representative cross-validation accuracy, predicted values were aggregated to blocks of land of size 500x500km. Results show that the average accuracy for predicting mean, maximum, and minimum daily temperatures is root-mean-square error (RMSE) =2 degrees C for areas densely covered with stations and between 2 degrees C and 4 degrees C for areas with lower station density. The lowest prediction accuracy was observed at high altitudes (>1000m) and in Antarctica with an RMSE around 6 degrees C. The model and predictions were built for the year 2011 only, but the same methodology could be extended for the whole range of the MODIS land surface temperature images (2001 to today), i.e., to produce global archives of daily temperatures (a next-generation repository) and to feed various global environmental models. Key Points Global spatio-temporal regression-kriging daily temperature interpolation Fitting of global spatio-temporal models for the mean, maximum, and minimum temperatures Time series of MODIS 8 day images as explanatory variables in regression par

Adherence measurements and corrosion resistance in primer/hot-dip galvanized steel systems

This paper focuses on the adherence during ageing of a primer (made of polyester resins crosslinked with melamine) applied onto hot-dip galvanized (HDG) steel for coil coating application and its influence on corrosion protection. A chromium-free surface treatment, composed of fluorotitanic acid, phosphoric acid, manganese phosphate, and vinylphenol was applied on the HDG steel to obtain high corrosion resistance and high adherence of a polyester and melamine primer. The influence of the manganese phosphate on the corrosion and adherence was investigated. To measure the adherence between the metal and the primer, a three-point flexure test was set up. The adherence was then linked with corrosion resistance during ageing, using electrochemical impedance spectroscopy

Zeleni inhibitori korozije sa cisteinom i kompleksom cerijum-cisteina na 7000 seriji aluminijumske legure

The aim of this study was to investigate environmentally-friendly corrosion inhibitors based on the cerium-cysteine and their effect on 7xxx series aluminum alloy. The cysteine and cerium-cysteine complex structures were analyzed by Fourier-Transform Infrared spectroscopy (FTIR). The structure of cerium-cysteine was additionally determined using Nuclear Magnetic Resonance (NMR) and Elemental Analysis. Inhibitors efficiency was analyzed with Electrochemical Impedance Spectroscopy (EIS) and Potentiodynamic polarization techniques in 0.1M NaCl at room temperature, while Scanning Electron Microscopy analyzed the surface appearance and microstructure of the tested aluminum alloy with Energy Dispersive Spectroscopy (SEM / EDS) and Optical Microscope (OM). Different amounts of cysteine were examined in order to find an optimal concentration of inhibitor. The adsorption of the inhibitors followed the Langmuir isotherm, and based on the EIS results and calculated thermodynamic potential (Gibbs free energy), cysteine and cerium-cysteine proved to be good inhibitors for tested aluminum alloy. The optimal cysteine concentration of 0.06 mM as a corrosion inhibitor of 7xxx series aluminum alloy was determined. EIS diagrams confirmed that cysteine showed better inhibition than Ce-Cys complex

Electrochemical deposition and characterization of zinc–nickel alloys deposited by direct and reverse current

Zn–Ni alloys electrochemically deposited on steel under various deposition conditions were investigated. The alloys were deposited on a rotating disc electrode and on a steel panel from chloride solutions by direct and reverse current. The influence of reverse plating variables (cathodic and anodic current densities and their time duration) on the composition, phase structure and corrosion properties were investigated. The chemical content and phase composition affect the anticorrosive properties of Zn–Ni alloys during exposure to a corrosive agent (3 % NaCl solution). It was shown that the Zn–Ni alloy electrodeposited by reverse current with a full period T = 1 s and r = 0.2 exhibits the best corrosion properties of all the investigated alloys deposited by reverse current

The Influence of Sm Content on the Surface Morphology and Corrosion Behavior of Zn-Co-Sm Composite Coatings

The influence of samarium, as an additional alloying element, on the morphology and corrosion performance of the Zn-Co-Sm alloy electrodeposited coatings, was investigated by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM/EDS) and electrochemical impedance spectroscopy (EIS) measurements. The Zn-Co-Sm coatings were electrodeposited from the aqueous solution containing Sm(NO3)3, ZnCl2, and CoCl2 as the metal ion source. The percentage of Sm in the coating may be very finely tuned by setting electrodeposition parameters, including cathodic current density, glycine concentration in the electroplating solution, and the solution temperature. The coatings with Sm content from 0.5 to 18.5 wt.% were produced. Since low deposition current densities (10–50 mA cm−2) were applied, the samples obtained were of good adhesion and compact. The presence of Sm2O3 inclusion was verified by XRD as the Sm2O3 crystalline phase. Samarium is incorporated in the coatings through the mechanism of oxide/hydroxide formation during the electroreduction of Zn and Co. Corrosion tests in NaCl solution show that the presence of Sm significantly increases the polarization resistance for the corrosion process of Zn-Co-Sm coatings (one order of magnitude, i.e., from ~500 Ω cm2 measured without Sm to 2000–3000 Ω cm2 with 12 wt.% Sm), giving evidence of the self-healing action that is provided by Sm particles in the coatings. This effect is more pronounced in the case when the coatings contain a higher Sm percentage

Mapping population change index in Southern Serbia (1961-2027) as a function of environmental factors

Niche analysis methods developed within the biogeography community are routinely used for species distribution modeling of wildlife and endangered species. So far, such techniques have not been used to explain distribution of people in an area, nor to assess spatio-temporal dynamics of human populations. In this paper, the MaxEnt approach to species distribution modeling and publicly available gridded predictors were used to analyze the population dynamics in Southern Serbia (South Pomoravlje Region) for the period 1961-2027. Population values from the census administrative units were first downscaled to 200 m grid using a detailed map of populated places and dasymetric interpolation. In the second step, a point pattern representing the whole population (468,500 inhabitants in 2002) was simulated using the R package spatstat. MaxEnt was then used to derive habitat suitability index (HSI) as a function of gridded predictors: distance to roads, elevation, slope, topographic wetness index, enhanced vegetation index and land cover classes. HSI and environmental predictors were further used to explain spatial patterns in the population change index (PCI) through regression modeling. The results show that inhabiting preference for year 1961 is mainly a function of topography (TWI, elevation). The HSI for year 2027 shows that large portions of remote areas are becoming less preferred for inhabiting. The results of cross-validation in MaxEnt show that distribution of population is distinctly controlled by environmental factors (AUC > 0.84). Population decrease is particularly significant in areas >25 km distant from the main road network. The results of regression analysis show that 40% of variability in the PCI values can be explained with these environmental maps, distance to roads and urban areas being the main drivers of migration process. This approach allows precise mapping of demographic patterns that otherwise would not be visible from the census data alone

Elektrohemijsko taloženje i karakterizacija legura cink-nikal dobijenih konstantnom i reversnom strujom

Zn-Ni alloys electrochemically deposited on steel under various deposition conditions were investigated. The alloys were deposited on a rotating disc electrode and on a steel panel from chloride solutions by direct and reverse current. The influence of reverse plating variables (cathodic and anodic current densities and their time duration) on the composition, phase structure and corrosion properties were investigated. The chemical content and phase composition affect the anticorrosive properties of Zn-Ni alloys during exposure to a corrosive agent (3%NaCl solution). It was shown that the Zn-Ni alloy electrodeposited by reverse current with a full period T = 1 s and r=0.2 exhibits the best corrosion properties of all the investigated alloys deposited by reverse current.Ispitivani su hemijski sastav i fazna struktura legura Zn-Ni dobijenih primenom različitih parametara elektrohemijskog taloženja. Legure su taložene na rotirajućoj disk elektrodi i na čeličnim pločicama konstantnom i reversnom strujom. Ispitivani su parametri reversne struje (katodne i anodne gustine struje taloženja, i njihovog vremena trajanja) na sastav, faznu strukturu i korozione osobine legura. Pokazano je da hemijski sastav i fazna struktura utiču na korozione osobine Zn-Ni legura tokom izlaganja dejstvu rastvora 3%NaCl. Legura Zn-Ni dobijena reversnom strujom sa T=1 s i r=0.2 ima najbolje korozione osobine