Photochemical alkene formation in sea water from dissolved organic carbon:results from laboratory experiments

The production mechanism of light alkenes, alkanes, and isoprene was investigated in laboratory experiments by measuring their concentrations in natural seawater as a function of spectral range, exposure time and origin, and concentration of dissolved organic carbon (DOC). The production mechanism of alkanes and of isoprene could not be clarified. Ethene and propene are produced photochemically from DOC. The relevant spectral range is UV and short‐wavelength visible light. Initial production rates (up to day 10 of exposure) were in the range of several pmol L−1 h−1 (mg DOC)−1; the corresponding mean quantum yields for the spectral range of 300–420 nm were about 10−8. Generally, the production rates and the quantum yields for ethene were about 2 times that of propene. The key factors in the total column integrated oceanic alkene production are the solar photon flux at sea surface, the penetration depth of the light into the ocean (especially the relation between different light absorbers, i.e., the extinction due to absorption of DOC), and the wavelength‐ and DOC‐dependent quantum yields. As a result of the high variability of these parameters, actual local alkene production rates for a specific oceanic region may differ considerably from the globally averaged oceanic alkene production rates. The latter were estimated to be at most 5 Mt yr−1

POSSIBILITIES OF OPEN ERUPTION ELIMINATION BY DRILLING TOOLS

The most important raw materials for different industries are oil and natural gas. With increasing consumption, the demand for drilling and the quality of production increases. Therefore, the exploration and production of hydrocarbons requires not only first-class machinery and technological equipment, but also qualified personnel. Exploration and drilling, production of hydrocarbons, like any other industry, cannot avoid accidents, emergencies and catastrophes. The worst type of well accident is undoubtedly an open eruption of the extracted crude oil. Open eruption can lead to serious injuries to the rig personnel, damage and destruction of equipment, negative environmental impact and loss of crude oil. Exploratory drilling can cause the rise of pressure and its subsequent manifestations. During the first deep drilling, there may not be enough information about the drilled horizons. If the reservoir pressure in the production horizon is higher than the hydrostatic pressure of the fluid in the well (for example, drilling mud), the formation fluids flow into the well and move towards the surface, which causes open eruption. The rig personnel must be properly trained to be able to recognize the occurrence of rising pressure by various signs and to respond effectively to the situation. Sometimes, under the influence of the human factor or equipment failure, open eruption still occurs. The article discusses the possibilities of eliminating open eruptions with drilling tools

Percolation in the classical blockmodel

Classical blockmodel is known as the simplest among models of networks with community structure. The model can be also seen as an extremely simply example of interconnected networks. For this reason, it is surprising that the percolation transition in the classical blockmodel has not been examined so far, although the phenomenon has been studied in a variety of much more complicated models of interconnected and multiplex networks. In this paper we derive the self-consistent equation for the size the global percolation cluster in the classical blockmodel. We also find the condition for percolation threshold which characterizes the emergence of the giant component. We show that the discussed percolation phenomenon may cause unexpected problems in a simple optimization process of the multilevel network construction. Numerical simulations confirm the correctness of our theoretical derivations.Comment: 7 pages, 6 figure

Tropopause and hygropause variability over the equatorial Indian Ocean during February and March 1999.

Measurements of temperature, water vapor, total water, ozone, and cloud properties were made above the western equatorial Indian Ocean in February and March 1999. The cold-point tropopause was at a mean pressure-altitude of 17 km, equivalent to a potential temperature of 380 K, and had a mean temperature of 190 K. Total water mixing ratios at the hygropause varied between 1.4 and 4.1 ppmv. The mean saturation water vapor mixing ratio at the cold point was 3.0 ppmv. This does not accurately represent the mean of the measured total water mixing ratios because the air was unsaturated at the cold point for about 40% of the measurements. As well as unsaturation at the cold point, saturation was observed above the cold point on almost 30% of the profiles. In such profiles the air was saturated with respect to water ice but was free of clouds (i.e., backscatter ratio <2) at potential temperatures more than 5 K above the tropopause and hygropause. Individual profiles show a great deal of variability in the potential temperatures of the cold point and hygropause. We attribute this to short timescale and space-scale perturbations superimposed on the seasonal cycle. There is neither a clear and consistent “setting” of the tropopause and hygropause to the same altitude by dehydration processes nor a clear and consistent separation of tropopause and hygropause by the Brewer-Dobson circulation. Similarly, neither the tropopause nor the hygropause provides a location where conditions consistently approach those implied by a simple “tropopause freeze drying” or “stratospheric fountain” hypothesis

Technical aspects of directional drilling with use a part of existing boreholes

Postęp techniki i technologii w wiertnictwie, umożliwia wykorzystywanie otworów kierunkowych w różnych sytuacjach wiertniczych. Otwory te stały się powszechnie wykorzystywane w wierceniach udostępniających złoża ropy naftowej i gazu ziemnego. Wiercenie otworów kierunkowych wykorzystuje kilka technik, które mogą być użyte do wiercenia otworów o złożonej trajektorii. Dzięki wierceniom kierunkowym można obniżyć koszty wiercenia poprzez użycie istniejących już otworów tak, aby przynajmniej ich część została wykorzystana w trakcie wiercenia nowego otworu. Taki sposób wiercenia wykorzystuje informacje i doświadczenia zdobyte podczas wiercenia istniejącego otworu, a to pozwala zaprojektować optymalną konstrukcję nowego otworu oraz zmniejsza ryzyko wystąpienia komplikacji wiertniczych. Artykuł analizuje możliwości wykorzystania różnych technik wiercenia otworów w przypadku wiercenia kierunkowego z już istniejącego otworu z uwzględnieniem technicznych możliwości ich zastosowania, niezbędnego wyposażenia oraz możliwości zwiększenia efektywności prac.Advancement in drilling techniques and technology enables using directional boreholes for a variety of drilling situations. Directional drilling technologies started to be commonly applied for gas and oil reservoir completion. The directional drillings use few techniques that can be applied to drill a borehole with the composed trajectory. Thanks using the directional drillings are possible to lower the drilling investment costs and increasing its efficiency by using some part of existing boreholes. Such idea of drilling let's take advantages of experiences collected while drilling of existing borehole, determinate proper borehole design and reduce the risk of drilling complications. This paper analyses possibility of using different techniques for directional drilling by using part of existing wellbore

Experiences with the construction of "The Research Polygon" for low potential energy acquisition from rock massive in areas of VSB - Technical University Ostrava-Poruba

Podczas wykonania i obsługi poligonów badawczych na terenie VSB - Uniwersytet Techniczny w Ostrawie autorzy uzyskali doświadczenia, które mogą zostać wykorzystane przy przygotowywaniu podobnych obiektów badawczych. Artykuł omawia doświadczenia zdobyte przy projektowaniu i realizacji dużego poligonu doświadczalnego wykonanego w pobliżu Nowej Auli VSB (największego budynku w Republice Czeskiej ogrzewanego przy użyciu pomp ciepła) i małego poligonu doświadczalnego zlokalizowanego w pobliżu Centrum Bada Energetycznych. Oba poligony wykonano w obrębie campusu VSB - Uniwersytet Techniczny w Ostrawie.During realization and operating of Research Polygons in areas of VSB - Technical University of Ostrava and AGH Kraków authors took many experiences which can be used for next construction of similar. This article will discuss experiences from realization and construction of the Large Research Polygon near the building Nova Aula (the biggest building in the Czech Republic which use heat pumps) and Small Research Polygon near the building Research Energetic Centrum, both in campus of VSB - Technical University of Ostrava, and also the results of the similar research polygon situated in the area of Drilling, Oil-Gas Faculty AGH Kraków