Sulfur in kukersite shale oil: its distribution in shale oil fractions and the effect of gaseous environment

In this article, we present data on the distribution of sulfur in Estonian kukersite shale oil. It was found that the highest concentration of sulfur is present in the fractions boiling between about 150 and 190°C. Also, we studied the effect of N2, N2/steam, CO2, and CO2/steam environments on the concentrations of some sulfur compounds in shale oil. The results show that thiophenic compounds comprise most of the sulfur compounds in crude kukersite shale oil. Furthermore, CO2 increased the concentration of some of the identified sulfur compounds in the shale oil as compared to N2. The presence of steam significantly increased the concentration of sulfur compounds in the oil as compared to dry sweeping gases. This was also supported by investigation of the release of H2S and SO2 gases during the pyrolysis of oil shale in which steam enhanced the release of sulfurous gases. The presence of steam not only enhances the release of sulfur compounds from oil shale, but also causes it to occur at lower temperatures.

Special Cases of Using Visualization Technology for Analyzing the Dynamics of Gaseous Environment

A new visualization technology is presented, which was used in applied research when observing and modeling the dynamics of the flow of gaseous environments. In the process of developing and improving the technology, a set of experimental results was compiled to study the phenomenon of combustion and detonation of a hydrogen-oxygen mixture, as well as the phenomena of propagation, action, and interaction of shock waves and gas-dynamic structures. On the example of analyzing data on the dynamics of the formation of a vortex ring, the possibilities of verifying the computational model of the implemented physical process are shown. The presented results reflect the level of information content when using technology to carry out tests.

Process Steps for High Quality Si-Based Epitaxial Growth at Low Temperature via RPCVD

The key process steps for growing high-quality Si-based epitaxial films via reduced pressure chemical vapor deposition (RPCVD) are investigated herein. The quality of the epitaxial films is largely affected by the following steps in the epitaxy process: ex-situ cleaning, in-situ bake, and loading conditions such as the temperature and gaseous environment. With respect to ex-situ cleaning, dry cleaning is found to be more effective than wet cleaning in 1:200 dilute hydrofluoric acid (DHF), while wet cleaning in 1:30 DHF is the least effective. However, the best results of all are obtained via a combination of wet and dry cleaning. With respect to in-situ hydrogen bake in the presence of H2 gas, the level of impurities is gradually decreased as the temperature increases from 700 °C to a maximum of 850 °C, at which no peaks of O and F are observed. Further, the addition of a hydrogen chloride (HCl) bake step after the H2 bake results in effective in-situ bake even at temperatures as low as 700 °C. In addition, the effects of temperature and environment (vacuum or gas) at the time of loading the wafers into the process chamber are compared. Better quality epitaxial films are obtained when the samples are loaded into the process chamber at low temperature in a gaseous environment. These results indicate that the epitaxial conditions must be carefully tuned and controlled in order to achieve high-quality epitaxial growth.

Gaseous environment modulates volatile emission and viability loss during seed artificial ageing

Main conclusion Modulation of the gaseous environment using oxygen absorbers and/or silica gel shows potential for enhancing seed longevity through trapping toxic volatiles emitted by seeds during artificial ageing. Abstract Volatile profiling using non-invasive gas chromatography–mass spectrometry provides insight into the specific processes occurring during seed ageing. Production of alcohols, aldehydes and ketones, derived from processes such as alcoholic fermentation, lipid peroxidation and Maillard reactions, are known to be dependent on storage temperature and relative humidity, but little is known about the potential modulating role of the gaseous environment, which also affects seed lifespan, on volatile production. Seeds of Lolium perenne (Poaceae), Agrostemma githago (Caryophyllaceae) and Pisum sativum (Fabaceae) were aged under normal atmospheric oxygen conditions and in sealed vials containing either oxygen absorbers, oxygen absorbers and silica gel (equilibrated at 60% RH), or silica gel alone. Seeds of A. githago that were aged in the absence of oxygen maintained higher viability and produced fewer volatiles than seeds aged in air. In addition, seeds of A. githago and L. perenne aged in the presence of silica gel were longer lived than those aged without silica, with no effect on seed moisture content or oxygen concentration in the storage containers, but with silica gel acting as a volatile trap. These results indicate that the use of inexpensive oxygen absorbers and silica gel could improve seed longevity in storage for some species and suggests a potential, and previously unidentified, role for silica gel in ultra-dry storage.

PIPAC – overview of the method and first use in the Czech Republic

PIPAC is a new technique for intra-abdominal administration of aerosol chemotherapy in a gaseous environment (capnoperitoneum). It can be indicated for peritoneal spread of various origins, most commonly ovarian cancer, stomach cancer and colorectal cancer. Due to its mini-invasiveness, the application can be repeated. The article provides a brief overview of current views of PIPAC and describes the first experience with PIPAC in the Czech Republic.