33 research outputs found
On Short-Term and Long-Term Behavior of Large Diameter above Ground Steel Storage Tanks Founded on Glacial Tills
The paper summarizes settlement records taken over periods of weeks and up to 45 years on above ground steel storage tanks 20 m to 50 m in diameter, 14 m to 20 m high, founded on fine-grained glacial tills. Soil information for each of the tanks is provided from different sources such as conventional boreholes, test pits, and sometimes Dilatometer tests. Three newly constructed tanks have been instrumented with piezometers and a tank base hydraulic profiler for monitoring during hydrotesting. The presented long-term settlements for the older tanks, and the short-term monitoring data collected from the hydrotested tanks are examined and commented on with respect to the face value of the records. The ability to apply practical geotechnical engineering methods to provide reasonable predictions of the behavior of tank foundations is also discussed
Competing Agendas for Land use around airports
This chapter describes the core aspects of the land-use planning (LUP) element of the Balanced Approach (BA) by acknowledging the potential of effective LUP as one of the few anticipatory tools available to manage noise. It explores the planning shortcomings that fail to stop encroachment and, thus, the need for remedial mitigation actions such as sound insulation, compensation and buy-out. It goes on to outline core future challenges and steps to develop a better spatial understanding of noise through improved understanding of people’s soundscapes (e.g. via the ANIMA app). To illustrate how LUP challenges can be addressed, the chapter also presents case studies from Iasi Airport and on insulation campaigns, in Marseille and Heathrow respectively. It concludes with an exploration of the lessons that can be taken from LUP experience and examines how more comprehensive communication and engagement with key stakeholders underpins more effective application of planning tools
Oscillatory behavior of hollow grid cathode discharges
Multiple complex space-charge structures in unmagnetized low-temperature plasmas arise from ionization phenomena near additional negatively or positively biased electrodes or due to local constraints. Because of their usually spherical form, such structures are called fireballs. If they appear inside hollow grids, they are called inverted fireballs or plasma bubbles. The temporal evolution of such structures is often accompanied by strong plasma instabilities. The dynamics of complex space-charge structures have been investigated by using single spherical grid cathode with an orifice. Langmuir probe and optical emission spectroscopy were used to diagnose the structures. Measurements delivered the axial profiles of the plasma potential, electron temperature and density, and the densities of excited atoms and ions, that confirmed the formation of a fireball in the region near the orifice (also evidenced by visual observation). Inside the grid, a plasma bubble has developed, with a high ion density inside due to the hollow cathode effect. Information on the nonlinear dynamics of the complex space charge structures was obtained from the analysis of the oscillations of the discharge current
Concentric double hollow grid cathode discharges. Spectral investigations and phenomenological approach
A discharge plasma is created by simultaneously biasing two concentric spherical grids with
axisymmetric orifices. In this geometry, space charge structures in the form of multiple
quasi-spherical luminous plasma bodies appear simultaneously inside and around the
cathodes. The plasma formations are highly interdependent supplying each other with the
particle flow and current closure necessary for the maintenance of the discharge. To diagnose
these structures, space-resolved cold Langmuir probe measurements and optical emission
spectroscopy investigations were performed in the axial direction allowing for the mapping of
the axial profiles of plasma potential, electron temperature and density, ion density and optical
emission. The existence of an accelerating double layer in the vicinity of the holes has been
confirmed here, and in previous research (Teodorescu-Soare C T et al 2016 Phys. Scr. 91
034002; Schrittwieser R W et al 2017 Phys. Scr. 92 044001; Teodorescu-Soare C T et al 2019
Int. J. Mass Spectrom. 436 83). Besides the assessment of the relationship between discharge
conditions and plasma parameters in the novel cathode system, the importance of a multiple
concentric cathode discharge configuration is revealed for deposition applications
Optimized synthesis of new N-mustards based on 2-mercaptobenzoxazole derivatives with antitumor activity
New di-( -chloroethyl)-amides of some acids derived from 2-mercaptobenzoxazole were
prepared by reaction of the corresponding pivalic mixed anhydrides with di-( -chloroethyl)-amine. A
study regarding the optimization of the chemical reactions was made for the case of di-( -chloroethyl)-
amines. The quantum chemical analysis by Spartan’14 was made in order to establish the most stable
configuration of the ground electronic states for the obtained chemical structures and some physicochemical
parameters of N-mustards reported in this paper. Mercaptobenzoxazoles substituted in the
side chain with the cytotoxic group show antitumor activity and they inhibit Ehrlich Ascites in an
appreciable proportion compared to the drug I.O.B.-82, as our studies evidenced
Drug and temperature influence on the gel state stability of the phospholipid membranes
The amphiphilic phospholipids have two hydrophobic fatty acids separated by charged hydrophilic head groups. They can form bilayers with the interior fatty acids oriented parallel to each other and with the phospholipid heads facing out in contact with water. In order to avoid the complexity of the natural membranes, these bilayers are used as model membranes. At room temperature the model membranes are characterized by a high degree of order in the gel state and, at higher temperature they pass, by a sudden process, in a less ordered state of liquid crystalline type. This phenomenon depends on the phospholipid type as well as on the nature of the possible impurities and it is conditioned by temperature. Our studies were made for dipalmitoylphophatidylcholine model membranes in which some drugs as gramicidin S and nifedipine were added to establish the drug influence on the main phase transition temperature. Gramicidin S decreases the main phase transition temperature, while nifedipine increases the temperature of the main phase transition of DPPC model membranes. Research of the model membranes near the main phase transition can facilitate the understanding of the destabilization by the drug action mechanism of the biological membranes
Complex formation and microheterogeneity in water–alcohol binary mixtures investigated by solvatochromic study
The water–alcohol binary mixtures have been extensively investigated by experimental and theoretical approaches, since they are extensively used in several industrial processes, being also very important in life sciences. Solvatochromism involves the use of spectrally active molecules (absorbing in the investigated spectral range) as probes introduced in a transparent solvent in small concentrations, so that the intermolecular interactions between its molecules can be neglected. The shift of the absorption spectral band of solute when dissolved is related to the intermolecular interactions between the solute’s molecules and the solvent molecules. Here, we report on the solvatochromic investigation of water–alcohol binary mixtures, based on experimentally measured absorption spectra. For the binary solvents, the composition of the first solvation shell (which have the most important contributions to the total shift of the solute’s spectral band) is different from that one existing in the whole solution. This happens, because the molecules of the active solvent (the one whose molecules stronger interact with the solute’s molecules) will be to a greater extent in the first solvation shell of the solute’s molecule. Three theoretical models were comparatively applied to estimate the composition of the first solvation shell of the solute’s molecule and thus to assess the solvatochromic data: statistical cell model of ternary solutions, Suppan model, and Bosch-Rosés model. Information on the water–alcohol complex formation (by hydrogen bonds) was obtained, as well as on the microheterogeneity of the binary mixture. The obtained data also allow the estimation of the interaction energy between two molecules in pairs solute–solvent
Space- and time-resolved raman and breakdown spectroscopy: advanced lidar techniques
DARLIOES - the advanced LIDAR is based on space- and time-resolved RAMAN and breakdown spectroscopy, to investigate chemical and toxic compounds, their kinetics and physical properties at high temporal (2 ns) and spatial (1 cm) resolution. The high spatial and temporal resolution are needed to resolve a large variety of chemical troposphere compounds, emissions from aircraft, the self-organization space charges induced light phenomena, temperature and humidity profiles, ice nucleation, etc
Optical and Chemical Study of Quartz from Granitic Pegmatites
Of the nine quartz samples collected from the Contu - Negovanu granitic pegmatites (Southern Carpathians, Romania), three were separated under binocular lenses and turned into fine grained powders, for X-ray fluorescence (XRF) and inductively coupled plasma mass spectrometry (ICP-MS) investigation techniques, whilst the other six samples were prepared in thin slides for electron microprobe analyzer (EMPA) and optical investigations, using a Babinet compensator and a Rayleigh interferometer. The results show that the quartz samples belonging to the Contu-Negovanu granitic pegmatites are chemically very pure, showing an expected high participation of silica and only some remarkable contents of Fe, derived from iron oxide micro-inclusions finely disseminated in the quartz grains. The minor and trace elements distribution suggests that different crystallization conditions influenced the quartz composition, thus resulting some rather high contents of Ba, Rb, Sr and some REE contents (Ce) in the pegmatite quartz crystallized from alkali-and alkaline-earth-rich fluids, while the metamorphic quartz appears to be highly pure, showing no such presence. The analyzed quartz samples present birefringence parameters within the limits of other quartz samples and a decrease of the linear birefringence of quartz with the light wavelength increase is emphasized by the data obtained using the channeled spectrum