Development of the quality assurance/quality control procedures for a neutron interrogation system

In order to perform Quality Assurance/Quality Control (QA/QC) procedures for a system dedicated to the neutron interrogation of objects for the presence of threat materials one needs to perform measurements of reference materials (RM) i.e. simulants having the same (or similar) atomic ratios as real materials. It is well known that explosives, drugs, and various other benign materials, contain chemical elements such as hydrogen, oxygen, carbon and nitrogen in distinctly different quantities. For example, a high carbon-to-oxygen ratio (C/O) is characteristic of drugs. Explosives can be differentiated by measurement of both (C/O) and nitrogen-to-oxygen (N/O) ratios. The C/N ratio of the chemical warfare agents, coupled with the measurement of elements such as fluorine and phosphorus, clearly differentiate them from the conventional explosives. Here we present the RM preparation, calibration procedure and correlations attained between theoretical values and experimentally obtained results in laboratory conditions for C/O and N/C ratios of prepared hexogen (RDX), TNT, DLM2, TATP, cocaine, heroin, yperite, tetranitromethane, peroxide methylethylketone, nitromethane and ethyleneglycol dinitrate simulants. We have shown that analyses of the gamma ray spectra by using simple unfolding model developed for this purpose gave a nice agreement with the chemical formula of created simulants, thus the calibration quality was successfully tested

Global Open Data Remote Sensing Satellite Missions for Land Monitoring and Conservation: A Review

The application of global open data remote sensing satellite missions in land monitoring and conservation studies is in the state of rapid growth, ensuring an observation with high spatial and spectral resolution over large areas. The purpose of this study was to provide a review of the most important global open data remote sensing satellite missions, current state-of-the-art processing methods and applications in land monitoring and conservation studies. Multispectral (Landsat, Sentinel-2, and MODIS), radar (Sentinel-1), and digital elevation model missions (SRTM, ASTER) were analyzed, as the most often used global open data satellite missions, according to the number of scientific research articles published in Web of Science database. Processing methods of these missions’ data consisting of image preprocessing, spectral indices, image classification methods, and modelling of terrain topographic parameters were analyzed and demonstrated. Possibilities of their application in land cover, land suitability, vegetation monitoring, and natural disaster management were evaluated, having high potential in broad use worldwide. Availability of free and complementary satellite missions, as well as the open-source software, ensures the basis of effective and sustainable land use management, with the prerequisite of the more extensive knowledge and expertise gathering at a global scale

Synergetic effects of K, Ca, Cu and Zn in human semen in relation to parameters indicative of spontaneous hyperactivation of spermatozoa

We have observed that sperm quality parameters indicative of spermatozoa hyperactivation such are lower “ linearity ” and “ straightness ” , and as showed by this research “ elongation ” , were more pronounced in patients with normal spermiogram compared to the group of men with reduced sperm motility who were undergoing routine in vitro fertilisation. The research encompassed 97 men diagnosed with normozoospermia (n = 20), asthenozoospermia (n = 54) and oligoasthenozoospermia (n = 23). The findings indicate that sperm quality of patients with normal spermiogram diagnosed according to WHO criteria, may be compro- mised by showing premature spontaneous hyperactivation which can decrease the chances of natural conception. We assessed synergistic effects of multiple chemical ele- ments in ejaculated semen to find if premature spontaneous hyperactivation of spermato- zoa can be a sign of imbalanced semen composition especially of elements K, Ca, Cu and Zn. Human semen samples showing low or high baseline status of chemical elements con- centrations were found in samples from all three diagnostic groups. However, correlation of K/Ca and Cu/Zn ratios, taking into account samples from all three groups of men, were neg- ative at statistical significance level p = 0.01. We tested if the negative correlation between K/Ca and Cu/Zn ratio works for greater number of semen samples. We found the negative correlation to be valid for 175 semen samples at statistical significance of p = 0.00002. The ratio of K/Ca and Cu/Zn, i.e. increased concentrations of K and Zn in comparison to concen- trations of Ca and Cu, were associated with a decrease of “ straightness ” in the group of men with normal spermiogram and pronounced spontaneous hyperactivation of spermato- zoa, implying that these elements act in synergy and that the balance of elements and not their absolute concentrations plays the major role in premature spermatozoa hyperactiva- tion in ejaculated semen

The effect of aging on composition and surface of translucent zirconia ceramic

Objectives: To examine the effect of two aging protocols on the chemical and phase composition as well as the surface state of monolithic translucent zirconia ceramics. Material and Methods: Translucent zirconia ceramics KATANA- Zirconia STML with different surface treatments (no treatment, K1, K2 ; glazed, G1-G8 ; polished, P1-P8) underwent testing in order to examine how the two aging protocols (three-hour hydrothermal degradation in an autoclave at 134 °C and 2 bars: G1-G4, P1-P4, and sixteen-hour chemical degradation in four- percent acetic acid at 80 °C (ISO 6872): G5-G8, P5-P8) affect chemical composition, particularly the share of stabilizing yttrium oxide (Energy Dispersive XRay Fluorescence – EDXRF), phase composition (X-ray diffraction – XRD) and surface state in terms of roughness and gloss. Results: Aging protocols did not affect the tested chemical composition stability of specimens and a high share of stabilizing yttrium-oxide (≥10% of total content), which correlates with the absence of monoclinic phase. A decrease in gloss on all specimens is statistically significant. Chemical degradation substantially increased the surface roughness of tested specimens. Conclusions: Translucent monolithic zirconia demonstrated a stable chemical composition and resistance to tetragonal-to-monoclinic transformation. Surface gloss was significantly reduced, especially in polished specimens. Contrary to glazed specimens, the tested polished specimens manifested an increase in surface roughness. Glazing the surface of translucent monolithic zirconia produces better esthetic, tribological and hygienic effects than polishing