A new application of oxyreactive thermal analysis in marine algological studies

This is a preliminary study of the application of oxyreactive thermal analysis in algological investigations. Several species of Chlorophyta, Phaeophyta, Rhodophyta and Zostera marina taken from different stations off the southern Baltic coast have been studied. It is pointed out that oxyreactive thermal analysis can be used for taxonomical investigations in order to establish the systematic membership of certain species of algae based on fragments of thallus. This method can also be applied in order to establish environmental specificity by differentiating the chemical composition of certain species. It is also suitable for assessing biochemical differentiation among the various parts of the thallus

Statistical classification of soft solder alloys by laser-induced breakdown spectroscopy: review of methods

This paper reviews machine-learning methods that are nowadays the most frequently used for the supervised classification of spectral signals in laser-induced breakdown spectroscopy (LIBS). We analyze and compare various statistical classification methods, such as linear discriminant analysis (LDA), quadratic discriminant analysis (QDA), partial least-squares discriminant analysis (PLS-DA), soft independent modeling of class analogy (SIMCA), support vector machine (SVM), naive Bayes method, probabilistic neural networks (PNN), and K-nearest neighbor (KNN) method. The theoretical considerations are supported with experiments conducted for real soft-solder-alloy spectra obtained using LIBS. We consider two decision problems: binary and multiclass classification. The former is used to distinguish overheated soft solders from their normal versions. The latter aims to assign a testing sample to a given group of materials. The measurements are obtained for several laser-energy values, projection masks, and numbers of laser shots. Using cross-validation, we evaluate the above classification methods in terms of their usefulness in solving both classification problems

The taxonomy of the genus Enteromorpha Link in the Gulf of Gdańsk, a numerical approach

The genus Enteromorpha Link is one of the most common algae in the Gulf of Gdańsk. The literature mentions that several Enteromorpha species occur in the western part of the Gulf of Gdańsk. The material for analysis was collected in the littoral zone down to a depth of 1 m in the Gulf of Gdańsk and on the open Baltic coast once a month from April to November 1986. The taxonomical characters, the nature of the bottom sediments and the sampling season were used for describing OTUs. 6 dissimilarity coefficients and 7 clustering methods were employed. The two principal clusters and some intermediate OTUs are shown on the dendrograms. The difference between these two clusters lies in the morphological characters. In one of them, the filaments are unbranched, without prolification, and the cells are multilateral and rounded, setting in random fashion; in the second one the filaments are branched, and the cells are rectangular, setting in an orderly manner along the main axis and the branches. The remaining characters, especially the quantitative ones do not seem to be important from the cluster analysis point of view

Growth dynamics and morphology of plankton green algae from brackish waters under the influence of salinity, temperature and light

Nine unicellular green algal species isolated from the Gulf of Gdańsk phytoplankton were studied. The species were cultured within the salinity range of 0-35% at temperatures of 5-38°C and at light intensity (PAR) ranging within 20-380 μE/m2s. Four species were typical of brackish water, five being freshwater plants. In terms of temperature requirements, groups of three species each belonged to high temperature, mesothermophilic, and low-temperature strains. Most species required relatively high light intensities as growth of six of them was saturated at 120 μE/m2s

Gyrotron Technology

The article presents a microwave vacuum tube called gyrotron. Its applications, construction and principle of operation are briefly described. It is also discussed the issue of an appropriate electron beam generation and formation

The Microwave Sources for EPR Spectroscopy

Rapid development of many scientific and technical disciplines, especially in material science and material engineering increases a demand for quick, accurate and cheap techniques of materials investigations. The EPR spectroscopy meets these requirements and it is used in many fields of science including biology, chemistry and physics. For proper work, the EPR spectrometer needs a microwave source, which are reviewed in this paper. Vacuum tubes as well as semiconductor generators are presented such as magnetron, klystron, traveling wave tube, backward wave oscillator, orotron, gyrotron, Gunn and IMPATT diodes. In this paper main advantages of gyrotron usage, such as stability and an increased spectral resolution in application to EPR spectroscopy is discussed. The most promising and reliable microwave source is suggested

THz spectroscopy of explosive-related simulants and oxidizers

In this paper we report on measurement of spectra of commonly applied explosives, some materials which can be used for manufacture of explosive and THz simulants of explosives in transmission mode. Substances were prepared as pellets, and the measurements were performed using the Time Domain Spectroscopy system in the range 0.1–3.0 THz