1,057 research outputs found
Systematic Protocol for SASW Inversion
Spectral-analysis-of-surface-waves (SASW) is a nondestructive test method for characterization of the variation with depth of the shear modulus of soils. One drawback in SASW is the need for an experienced user to conduct the inversion. Difficulty in SASW inversion arises from lack of constraint of the least squares minimization used on shear wave velocity parameters. For even simple profiles. The inversion algorithm can exhibit instability due to numerical sensitivity of the forward model calculations. The user must provide a reasonable starting profile; and then the parameters must be carefully followed and constrained to reach convergence. The inversion process was explored using a range of dispersion curves ranging from simple to complex layering systems. Three key principles were built into a new protocol to provide necessary constraints on the inversion algorithm. Dispersion data from many test sites have been inverted using the new protocol. Careful adherence to the protocol consistently produces shear wave velocity profiles indicative of site conditions. The protocol provides logic necessary for automation of the inversion process
Properties of local produced animal-fat based biodiesel and its blend with fossil fuel
In the near future, more emphasis must be put on reducing greenhouse gas (GHG) emissions in road transportation, house heating, agricultural activities, marine transport etc. This study concentrated on the use of alternative fuels in engine - driven applicat ions of non - road machineries and decentralized energy production . Today, the engines are mainly designed for crude oil derived fuels and liquid renewable fuels are blended with crude oil based fuels to fulfill the requirements of renewable energy usage. Du e to the environmental reasons on one hand and to the agricultural needs, on the other hand , different blends of bio - and fossil fuels are becoming more popular. In Europe, the maximum FAME content in diesel fuel is 7 vol% according to the EN 590:2013 but higher percentages are also available and targeted around the world. For example in the United States, the 20% blend fraction is becoming more common. For these reasons, B20 fuels were chosen to be investigated in this study. Special emphasis was put on im proving blending issues since fuel blending may cause some operating risks. The main aim was to research widely the properties of animal - fat based methyl ester (AFME) and B20 fuel blend produced from it. AFME is a waste based fuel and produced in Ostroboth nia region, Finland. The aim was to find out in which engine applications the fuels are feasible and investigate if the fuels fit in the quality of automotive fuel Standards. According to the results, AFME is a feasible option to increase self - sufficient e ne rgy production in Ostrobothnia.fi=vertaisarvioitu|en=peerReviewed
Structure and thermal behaviour of dichlorobis(thiourea)cadmium(ii), a single-source precursor for CdS thin films
The title compound (1) crystallites in the space group Pmn2(1) with a =
13.110 (3), b = 5.813(1) and c = 6.482(1) Angstrom. Its crystal
structure was redetermined from three-dimensional single-crystal data
to a final R-value of 0.0221. The Cd2+ ion is tetrahedrally coordinated
to two sulfur atoms from the tiourea ligand (Cd-S = 2.509 Angstrom) and
to two chloride ions at distances 2.545 and 2.518 Angstrom. When heated
in air or in an inert atmosphere 1 undergoes a complex degradation
process which was studied in situ by simultaneous TG/DTA as well as by
EGA-FTIR. The gaseous species evolved include NH3, HCl, H2NCN, HNCS and
CS2, which upon oxidation yield also HCN, SO2, COS and CO2. In the
solid residue, NH4CdCl3 and CdS were detected by X-ray diffraction,
Elemental and XPS analyses also indicated the presence of Cl and N as
well as some carbon residue. The results of the thermoanalytical study
are not directly applicable to the spray pyrolysis process because of
the different experimental conditions, but they nevertheless indicate
that it is extremely difficult to prepare impurity-free CdS. The
formation of HCN, not detected earlier, should also be taken into
account when designing the process parameters and safety measures
Characterization of Abandoned Mine Sites Beneath I-70 Via Crosshole and SASW Seismic Wave Methods
An approximately 2100-ft section of Interstate 70 (I-70) experienced a series of ground failures in 1994 and 1995 that were attributed to collapse of underground mine workings. Repair of the roadway consisted of construction of barrier walls of stiff grout to contain production grout pumped into the mines. Beginning in spring 1996, depressions were noted in the pavement surface over some of the grouted holes. As a consequence, a two-part investigation was initiated to determine whether the surface expressions reflect subsurface conditions that are a risk to the travel lanes and traveling public. In Phase I, Test Area Investigation, various field and analytical methods were tested and evaluated on a small scale prior to broad-scale implementation in Phase II. Crosshole and SASW seismic wave methods of subsurface characterization were included in the Phase I investigation. The paper describes the test methods employed in the field, and documents data and test results obtained from the test area. It is shown that quality geophysical measurements can be made in close proximity to the active interstate, and that no single technique will unambiguously detect voids or other anomalies over a wide range of depths. Based upon these results, specific recommendations for the Phase II investigation are provided
Biochem Soc Trans
Abnormal protein aggregation and intracellular or extracellular accumulation of misfolded and aggregated proteins are key events in the pathogenesis of different neurodegenerative diseases. Furthermore, endoplasmic reticulum stress and impairment of the ubiquitin-proteasome system probably contribute to neurodegeneration in these diseases. A characteristic feature of AD (Alzheimer's disease) is the abnormal accumulation of Abeta (amyloid beta-peptide) in the brain. Evidence shows that the AD-associated PS (presenilin) also forms aggregates under certain conditions and that another AD-associated protein, ubiquilin-1, controls protein aggregation and deposition of aggregated proteins. Here, we review the current knowledge of ubiquilin-1 and PS in protein aggregation and related events that potentially influence neurodegeneration
Tannins, flavonoids and stilbenes in extracts of African savanna woodland trees Terminalia brownii, Terminalia laxiflora and Anogeissus leiocarpus showing promising antibacterial potential
Terminalia laxiflora, Terminalia brownii and Anogeissus leiocarpus are used as decoctions, macerations, infusions and fumigations in East and West African traditional medicine for treatment of infectious diseases and their symptoms. Using this ethnopharmacological information as a guideline for our research and owing to the fact that these species have not been subjected to in depth antibacterial and phytochemical studies, thirty-nine extracts of various polarities of the stem bark, stem wood and roots were studied for growth inhibitory effects against the human pathogenic bacteria Staphylococcus epidermidis, Staphylococcus aureus, Micrococcus luteus and Pseudomonas aeruginosa. Our results indicate that the studied species contain antibacterial compounds of a wide range of polarities. All polar root extracts of T. laxiflora and various polar extracts of T. brownii roots, including hot water decoctions, gave broad-spectrum antibacterial effects and low MIC values of 39 mu g/ml. The main ellagitannins in an ethyl acetate extract of the root of T. laxiflora were found to be corilagin and its derivative and punicalagin. A methanol extract of the roots of T. brownii contained methyl-(S)-flavogallonate and its derivative as the main identified ellagitannins. Moreover, both Terminalia species were found to contain ellagic acid xylopyranoside and methyl ellagic acid xyloside and pure ellagic acid was present in T. brownii. Pure punicalagin did not give as low MIC as an ethyl acetate extract of the roots of T. laxiflora, containing punicalagin as one of its main compounds, although this ellagitannin totally inhibited the growth of S. aureus at 125 mu g/ml and P. aeruginosa at 500 mu g/ml. Similarly, pure ellagic and gallic acid gave higher MIC values than the methanolic root extract of T. brownii against S. aureus and P. aeruginosa. Moreover, a Sephadex LH-20 fraction of the methanolic extract of the roots of T. brownii, enrichedwithmethyl-(S)-flavogallonate and its isomer, gave higher MIC values than the crude methanolic extract. These results suggest that the polyphenols in the extracts might act synergistically with each other. A methanolic soxhlet extract of the roots of A. leiocarpus, containing ampelopsin, aromadendrin, taxifolin, pinosylvin and 4'-methylpinosylvin gave a low MIC value of 39 mu g/ml against all bacterial strains used in this investigation. Our results demonstrate that the roots, stem bark and stem wood of T. brownii, T. laxiflora and A. leiocarpus are rich sources of (new) antimicrobial compounds and justify the uses of these plants for treatment of infections in African traditional medicine.Peer reviewe
Performance and flow dynamics studies of polymeric optofluidic sers sensors
We present a polymer-based optofluidic surface enhanced Raman scattering chip for biomolecule detection, serving as a disposable sensorchoice with cost-effective production. The SERS substrate is fabricated by using industrial roll-to-roll UV-nanoimprinting equipment andintegrated with adhesive-based polymeric microfluidics. The functioning of the SERS detection on-chip is confirmed and the effect of thepolymer lid on the obtainable Raman spectra is analysed. Rhodamine 6G is used as a model analyte to demonstrate continuous flowmeasurements on a planar SERS substrate in a microchannel. The relation between the temporal response of the sensors and sample flowdynamics is studied with varied flow velocities, using SERS and fluorescence detection. The response time of the surface-dependent SERSsignal is longer than the response time of the fluorescence signal of the bulk flow. This observation revealed the effect of convection on thetemporal SERS responses at 25 μl/min to 1000 μl/min flow velocities. The diffusion of analyte molecules from the bulk concentration intothe sensing surface induces about a 40-second lag time in the SERS detection. This lag time, and its rising trend with slower flow velocities, has to be taken into account in future trials of the optofluidic SERS sensor, with active analyte binding on the sensing surface
An integrated Young interferometer based on UV-imprinted polymer waveguides for label-free biosensing applications
We demonstrate a polymer rib waveguide Young interferometer sensor fabricated by UV-imprinting. An inverted rib waveguide structure was utilized in order to simplify the fabrication process. In this configuration grooves are formed on the under cladding layer by UV-imprinting and core material is spin coated on top to fill the grooves. Glucose water solution was used to characterize the sensor response against ambient refractive index changes. The sensing responses correspond linearly with the refractive index change of glucose solutions with a detection limit of about 10-5. To verify the capability of the polymer sensor for biosensing, an immunoassay was performed with c-reactive protein (CRP) and human CRP specific antibody adsorbed on the waveguide surface as a receptor. The CRP solution in PBS (phosphate buffered saline) buffer with a concentration of 2 µg/ml (16 nM) resulted in an obvious response which was over a couple hundred times of the noise level. Based on these values, a detection limit of about 2.4 pg/mm2 was found for the surface sensing of molecular adsorption. With the proposed waveguide configuration, the fabrication of polymer sensors can be ultimately transferred to roll-to-roll mass production to produce low-cost disposable sensors
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