Petromagnetic and paleomagnetic characterization deposits at Mesozoic/Cenozoic boundary: The Tetritskaro section (Georgia)

Petromagnetic and magnetostratigraphic characteristics are obtained for the Tetritskaro section. The boundary layer at the Mesozoic/Cenozoic (K/T) boundary is fixed primarily by an abrupt rise in the paramagnetic magnetization (total Fe concentration) and, to a lesser degree, by an increase in the concentration of such magnetic minerals as goethite, hemoilmenite, and magnetite. The along-section distribution of titanomagnetite of volcanic origin and metallic iron of cosmic origin does not correlate with the K/T boundary and lithologic properties of the sediments. The boundary of the Mesozoic and Cenozoic geological eras lies within the reversed polarity chron C29r and is marked by an abrupt rise in the geomagnetic field paleointensity and an instability of paleomagnetic directions, rather than by a polarity change. The accumulation time of the boundary clay layer is about 1.5-2 kyr, while abrupt changes in the paleointensity and direction of the geomagnetic field encompass 30-40 kyr. Such long occurrence intervals of the events in question cannot be related to a short-term impact phenomenon. © Pleiades Publishing, Ltd. 2009

Petromagnetic and paleomagnetic characterization deposits at Mesozoic/Cenozoic boundary: The Tetritskaro section (Georgia)

Petromagnetic and magnetostratigraphic characteristics are obtained for the Tetritskaro section. The boundary layer at the Mesozoic/Cenozoic (K/T) boundary is fixed primarily by an abrupt rise in the paramagnetic magnetization (total Fe concentration) and, to a lesser degree, by an increase in the concentration of such magnetic minerals as goethite, hemoilmenite, and magnetite. The along-section distribution of titanomagnetite of volcanic origin and metallic iron of cosmic origin does not correlate with the K/T boundary and lithologic properties of the sediments. The boundary of the Mesozoic and Cenozoic geological eras lies within the reversed polarity chron C29r and is marked by an abrupt rise in the geomagnetic field paleointensity and an instability of paleomagnetic directions, rather than by a polarity change. The accumulation time of the boundary clay layer is about 1.5-2 kyr, while abrupt changes in the paleointensity and direction of the geomagnetic field encompass 30-40 kyr. Such long occurrence intervals of the events in question cannot be related to a short-term impact phenomenon. © Pleiades Publishing, Ltd. 2009

Petromagnetic and paleomagnetic characterization deposits at Mesozoic/Cenozoic boundary: The Tetritskaro section (Georgia)

Petromagnetic and magnetostratigraphic characteristics are obtained for the Tetritskaro section. The boundary layer at the Mesozoic/Cenozoic (K/T) boundary is fixed primarily by an abrupt rise in the paramagnetic magnetization (total Fe concentration) and, to a lesser degree, by an increase in the concentration of such magnetic minerals as goethite, hemoilmenite, and magnetite. The along-section distribution of titanomagnetite of volcanic origin and metallic iron of cosmic origin does not correlate with the K/T boundary and lithologic properties of the sediments. The boundary of the Mesozoic and Cenozoic geological eras lies within the reversed polarity chron C29r and is marked by an abrupt rise in the geomagnetic field paleointensity and an instability of paleomagnetic directions, rather than by a polarity change. The accumulation time of the boundary clay layer is about 1.5-2 kyr, while abrupt changes in the paleointensity and direction of the geomagnetic field encompass 30-40 kyr. Such long occurrence intervals of the events in question cannot be related to a short-term impact phenomenon. © Pleiades Publishing, Ltd. 2009

Petromagnetic and paleomagnetic characterization deposits at Mesozoic/Cenozoic boundary: The Tetritskaro section (Georgia)

Petromagnetic and magnetostratigraphic characteristics are obtained for the Tetritskaro section. The boundary layer at the Mesozoic/Cenozoic (K/T) boundary is fixed primarily by an abrupt rise in the paramagnetic magnetization (total Fe concentration) and, to a lesser degree, by an increase in the concentration of such magnetic minerals as goethite, hemoilmenite, and magnetite. The along-section distribution of titanomagnetite of volcanic origin and metallic iron of cosmic origin does not correlate with the K/T boundary and lithologic properties of the sediments. The boundary of the Mesozoic and Cenozoic geological eras lies within the reversed polarity chron C29r and is marked by an abrupt rise in the geomagnetic field paleointensity and an instability of paleomagnetic directions, rather than by a polarity change. The accumulation time of the boundary clay layer is about 1.5-2 kyr, while abrupt changes in the paleointensity and direction of the geomagnetic field encompass 30-40 kyr. Such long occurrence intervals of the events in question cannot be related to a short-term impact phenomenon. © Pleiades Publishing, Ltd. 2009

Ultrasonic Methods for Assessing the State of Hydrotechnic Concrete Structures

კვლევების მიზანი იყო ცაგერის წყალშემკრების თანამედროვე მდგომარეობის გეოფიზიკური მეთოდებით შესწავლა. ამ მეთოდების ერთ-ერთი სახეა ულტრაბგერითი კვლევების მეთოდი. ამ მეთოდით შესაძლებელია საკვლევი ობიექტის დრეკადი პარამეტრების გაზომვა და გამოთვლა, მისი დაზიანების გარეშე. საკვლევ ობიექტზე ხდებოდა ულტრაბგერითი გრძივი (P) და განივი (S) ტალღების გავრცელების სიჩქარეების გაზომვა. შემდეგ გამოთვლილი სიჩქარეების საფუძველზე მასალის სიმკვრივის (ρ) პუასონის კოეფიციენტის (ν) და იუნგის მოდულის (E) გამოთვლა. ულტრაბგერითი ხელსაწყო-დანადგარების საშუალებით შესაძლებელია საკვლევი გარემოს ე.წ. ტომოგრაფია, მისი „გაშუქება“ ცალი მხრიდან არეკლილი ტალღების საშუალებით. ამ შემთხვევაში შესაძლებელია საკვლევ სხეულში არსებული, გარკვეული ზომის სიცარიელეების, არაერთგვაროვანი უბნების დაფიქსირება და სხვადასხვა სიმკვრივის (შესუსტებული) უბნების გამოყოფა.The purpose of these studies was to study the current state of the Tsageri catchment by geophysical methods. One such method is the ultrasound method. This method can measure and calculate the elastic parameters of the object of study without damaging it. We measured the propagation velocities of ultrasonic longitudinal (P) and shear waves (S) at the studied object. Then, material density (ρ), Poisson's ratio (ν) and Young's modulus (E) were calculated based on the measured speed. Ultrasonic devices, availability in our laboratory, can be used for the socalled tomography, "coverage" from the one side with the help of reflected waves. In this case, it is possible to identify voids of certain sizes, inhomogeneous regions in the body under study, and to distinguish regions of different densities (weakened)

Botany and taxonomy of pear

Pear belongs to the Rosaceae family as most of the cultivated fruit trees. It is the second fruit tree crop in terms of production after apple. Its production has increased these last decades to reach a world production of more than 27 megatons for almost 1,600,000 ha. Pears have been cultivated in Europe and in Asia for more than 5,000 years. Of all known and reported pear species and interspecific hybrids, five are mainly cultivated. These include the European pear, Pyrus communis, and the Asian pears P. pyrifolia, P. ×bretschneideri, P. ussuriensis, and P. sinkiangensis. Fruits of European pears are elongated and have a full-bodied texture, while those of Asian pears are round and have a sandy texture. The Pyrus genus belongs to the Amygdaloideae subfamily and the Malinae tribe, and consists of about 75 to 80 species and interspecific hybrid species. As several hybridizations are observed among Pyrus species, this renders the distinction among some pear species rather difficult. The origin of the Pyrus genus dates back to the Oligocene Epoch, about 33.35 to 25.23 Mya. It is a genus of mainly deciduous trees and shrubs spread throughout temperate Eurasia, reaching the Atlas Mountains in North Africa, and extending to Japan and South China. Pyrus species produce generally simple leaves alternately arranged. Leaves are glossy green on some species, densely silvery-hairy in some others. Pyrus flowers are white, borne in corymbs on short spurs or lateral branchlets, and are composed of five sepals, five petals, numerous stamens, and usually a five-locular ovary with free styles. The Pyrus fruit is a pseudo-fruit composed of the receptacle or the calyx tube, greatly dilated, enclosing the true fruit, and consisting of five cartilaginous carpels, known as the core. Morphological characters of the leaf, fruit, and calyx are commonly used to differentiate among Pyrus species. There are thousands of pear cultivars over the world with wide diversity for fruit shape, taste, and texture. In this chapter, we have focused on the description of cultivated Pyrus species and on some of the main cultivated cultivars