Vyraujančios vėjo krypties matematinis modelis

Santr. anglVytauto Didžiojo universitetasŽemės ūkio akademij

Traumatic spleen rupture diagnosed during postmortem dissection A STROBE-compliant retrospective study

Spleen is typically injured in blunt abdominal trauma. Spleen injuries make 42% of all blunt abdominal injuries. The aim of this study was to perform a retrospective assessment of the cases of acute and subacute isolated traumatic spleen ruptures. A retrospective study performed on 50 patients, whose cause of death was isolated spleen rupture and bleeding into the abdominal cavity. An acute spleen rupture was diagnosed in 47 cases, whereas the rest 3 cases demonstrated a subacute rupture. In cases of acute spleen rupture, the mean weight of spleen was 309.6 g, whereas in 3 cases of subacute rupture the mean weight of the organ achieved 710 g. The mean weight of spleen in the control group with no spleen rupture was 144.7 g. Recording of the cases of isolated acute and subacute traumatic spleen ruptures and morphological assessment of them are important in forensic pathology science and in clinical practice as well

Injection-Triggered Occlusion of Flow Pathways in Geothermal Operations

Reasons for injectivity decline were investigated in a low-enthalpy geothermal aquifer in Klaipeda (Lithuania). It is one of the study sites within the DESTRESS project, which demonstrates different stimulation techniques in geothermal reservoirs. Due to low injectivity, production rates from the Lithuanian field are currently reduced, which lead to negative commercial implications for the site. Productivity from the same wells is measured to be 40 times higher. Injectivity decline in aquifers is often related to clogging processes in spatially correlated highly permeable structures, which control the main flow volume. We subdivided clogging processes into (1) physical, (2) chemical, and (3) biological processes and studied them by analyzing fluid and solid samples as well as operational data. The methods we used are fluid and solid analyses in situ, in the laboratory and in experimental setups, statistical interpretation, and numerical modeling. Our results show that the spatially correlating nature of permeable structures is responsible for exponentially decreasing injectivity because few highly permeable zones clog rapidly by intruded particles. In particular, field operations cause changes of the physical, chemical, and biological processes in the aquifer. Mineral precipitation and corrosion are the main chemical processes observed at our site. Microbial activity causes biofilm while fines migration is caused by changes in physical boundary conditions. Moreover, these processes can affect each other and generate further reactions, for example, microbial activity triggers corrosion in surface pipelines

A Review of the Hydrochemistry of a Deep Sedimentary Aquifer and Its Consequences for Geothermal Operation: Klaipeda, Lithuania

The Klaipeda Geothermal Demonstration Plant (KGDP), Lithuania, exploits a hypersaline sodium-chloride (salinity c. 90 g/L) groundwater from a 1100 m deep Devonian sandstone/siltstone reservoir. The hydrogen and oxygen stable isotope composition is relatively undepleted (δ18O=c. -4.5‰), while the δ34S is relatively “heavy” at +18.9‰. Hydrochemical and isotopic data support the existing hypothesis that the groundwater is dominated by a hypersaline brine derived from evapoconcentrated seawater, modified by water-rock interaction and admixed with smaller quantities of more recent glacial meltwater and/or interglacial recharge. The injectivity of the two injection boreholes has declined dramatically during the operational lifetime of the KGDP. Initially, precipitation of crystalline gypsum led to a program of rehabilitation and the introduction of sodium polyphosphonate dosing of the abstracted brine, which has prevented visible gypsum precipitation but has failed to halt the injectivity decline. While physical or bacteriological causes of clogging are plausible, evidence suggests that chemical causes cannot be excluded. Gypsum and barite precipitation could still occur in the formation, as could clogging with iron/manganese oxyhydroxides. One can also speculate that inhibitor dosing could cause clogging of pore throats with needles of calcium polyphosphonate precipitate