SAR Oil Spill Detection System through Random Forest Classifiers

A set of open-source routines capable of identifying possible oil-like spills based on two random forest classifiers were developed and tested with a Sentinel-1 SAR image dataset. The first random forest model is an ocean SAR image classifier where the labeling inputs were oil spills, biological films, rain cells, low wind regions, clean sea surface, ships, and terrain. The second one was a SAR image oil detector named “Radar Image Oil Spill Seeker (RIOSS)”, which classified oil-like targets. An optimized feature space to serve as input to such classification models, both in terms of variance and computational efficiency, was developed. It involved an extensive search from 42 image attribute definitions based on their correlations and classifier-based importance estimative. This number included statistics, shape, fractal geometry, texture, and gradient-based attributes. Mixed adaptive thresholding was performed to calculate some of the features studied, returning consistent dark spot segmentation results. The selected attributes were also related to the imaged phenomena’s physical aspects. This process helped us apply the attributes to a random forest, increasing our algorithm’s accuracy up to 90% and its ability to generate even more reliable results.

Evolution of the Laser-Induced Spallation Technique in Film Adhesion Measurement

Laser-induced spallation is a process in which a stress wave generated from a rapid, high-energy laser pulse initiates the ejection of surface material opposite the surface of laser impingement. Through knowledge of the stress wave amplitude that causes film separation, the adhesion and interfacial properties of a film-on-substrate system are determined. Some advantages of the laser spallation technique are the non-contact loading, development of large stresses (on the order of GPa) and high strain rates, up to 108 /s. The applicability to both relatively thick films, tens of microns, and thin films, tens of nm, make it a unique technique for a wide range of materials and applications. This review combines the available knowledge and experience in laser spallation, as a state-of-the-art measurement tool, in a comprehensive pedagogical publication for the first time. An historical review of adhesion measurement by the laser-induced spallation technique, from its inception in the 1970s through the present day, is provided. An overview of the technique together with the physics governing the laser-induced spallation process, including functions of the absorbing and confining materials, are also discussed. Special attention is given to applications of laser spallation as an adhesion quantification technique in metals, polymers, composites, ceramics, and biological films. A compendium of available experimental parameters is provided that summarizes key laser spallation experiments across these thin film materials. This review concludes with a future outlook for the laser spallation technique, which approaches its semicentennial anniversary.

FORMATION OF BIOLOGICAL FILMS OF MICROORGANISMS ON VARIOUS SURFACES OF THE ENVIRONMENT

The article presents material on the results of experimental studies on the formation of biofilms by microorganisms of individual taxonomic groups on various surfaces of objects of the environment. The time and degree of biofilm formation, as well as the dependence on the type of surface and bacteria, were established. The cultures of the genera Salmonella, E. coli, Yersinia, Proteus, Pseudomonas and Staphylococcus were used in the work. To study the formation of biofilms, 24-hour cultures of S-form microorganisms grown on solid or in liquid nutrient media were used. Test objects were stained with 0,1% crystalline violet solution for 15 minutes, unbound dye was washed off with physiological saline or distilled water. Test objects were placed on filter paper and dried. Then 200 microliters of 96% ethanol were added to extract the paint from the film and the optical density was measured on a KFK-3KM spectrophotometer at wavelength of 590 nm. It was found that conditionally pathogenic and pathogenic microorganisms form a biofilm on both smooth and rough abiotic surfaces within 48 hours. Moreover, the intensity of biofilm formation on rough surfaces is higher than on smooth ones by 15...30%. Among the studied microorganisms, the most intensive development of biofilm was observed in Ps. cultures. aeruginosa and Pr. vulgaris. Biofilms pose a potential danger of contamination of feed, food raw materials and, most importantly, food products, since they can exist for a long time on a wide variety of surfaces of production facilities of the respective enterprises.

Biofilm rupture by laser-induced stress waves increases with loading amplitude, independent of location

Integral to the production of safe and biocompatible medical devices is to determine the interfacial properties that affect or control strong biofilm adhesion. The laser spallation technique has recently emerged as an advantageous method to quantify biofilm adhesion across candidate biomedical surfaces. However, there is a possibility that membrane tension is a factor that contributes to the stress required to separate biofilm and substrate. In that case, the stress amplitude, controlled by laser fluence, that initiates biofilm rupture would vary systematically with location on the biofilm. Film rupture, also known as spallation, occurs when film material is ejected during stress wave loading. In order to determine effects of membrane tension, we present a protocol that measures spall size with increasing laser fluence (variable fluence) and with respect to distance from the biofilm centroid (iso-fluence). Streptococcus mutans biofilms on titanium substrates serves as our model system. A total of 185 biofilm loading locations are analyzed in this study. We demonstrate that biofilm spall size increases monotonically with laser fluence and apply our procedure to failure of non-biological films. In iso-fluence experiments, no correlation is found between biofilm spall size and loading location, thus providing evidence that membrane tension does not play a dominant role in biofilm adhesion measurements. We recommend our procedure as a straightforward method to determine membrane effects in the measurement of adhesion of biological films on substrate surfaces via the laser spallation technique.Graphical Abstract

Neoproterozoic microbially-induced sedimentary structures (MISS) from Ediacaran Podillya Basin, Ukraine: mineralogical particularity and paleoenvironmental application

The Neoproterozoic Podillya sedimentary Basin is well known to the imprints of the Ediacaran soft-bodied fauna which were previously described by many ukrainian and foreign authors. At this period, fossil-rich siliciclastic sediments recognized as traces of early metazoans also contain evidence of significant microbiological activity. In these ediacaran sediments, many structures can be interpreted as microbially induced sedimentary structures (MISS). Their morphologies have a great similarity with modern structures observed in relation with micro-organism activity. These specific structure and surfaces and their mineral composition are the criteria used to study the bacterial structures from the ukrainian Neoproterozoic sedimentary basin. Our results demonstrate microorganisms were organized in bacterial mats whose activity was recorded in the difference of mineralogy between biological films and host rocks. On outcrop, the different type of MISS are often associated with lenticular beddings, ripples and hummocky cross structures indicative of coastal-marine conditions close to the littoral zone of the basin at this epoch. If MISS are important in the issue of paleogeographic reconstructions, they also give precious informations about early diagenetic processes, syn- and post-sedimentation. By mineralogical approach we show that during the time of development of MISS structures and the burial that followed the diagenetic processes have remained moderate. Finally, the close coexistence with ediacarian fossils suggest that such bacterial mats could be at the origin of the fossilization process of soft-bodies of enigmatic Ediacaran biota of Mohyliv-Podylska Group and their preservation until today.

Biopolymeric materials containing brown algae polysaccharides

This article describes the use of polymeric systems created on the basis of natural or synthetic polymers. One of the most safe and biocompatible is fucoidan. Therefore, were proposed and developed the idea of creating films based on methylcellulose with fucoidan with the addition of various plasticizers. It was found that surface films affect the healing of wounds, as it causes the ability of the cells adhesion, the adsorption of water molecules. Also was investigated the physical properties of the films with different plasticizers, for example use as a plasticizer of the lactic acid allows to increase the capacity for swelling, as well as increase the ability to retain adsorbed, which is necessary for healing of wounds after burns. The use of glycerin or propylene glycol resulted in a decrease in the degree of swelling, and the absence of the plasticizer contributes to enhancement of the adsorption of water molecules. Data from biological films possess high ability to swell, and therefore not only applicable for the treatment of wounds with lots of exudate, but due to the high holding capacity applicable for low exudative wounds.