Experimental characterization of the flow field of square prism with a detached splitter plate at high reynolds number

The characteristics of the flow field of a square prism with detached splitter plate in its wake were investigated by measuring the fluid force on the prism and by visualizing the flow field through particle image velocimetry (PIV) with a high Reynolds number (Re = 10,000). The experimental parameters included the ratios of the splitter and prism widths (H/B = 0.5–1.5) as well as the gap ratios (G/B = 0–2) between the prism and the splitter plate at a high Reynolds number (Re = 10,000). The drag reduction rate of the square prism increased with increasing H/B for the same G/B; meanwhile, it increased and then decreased with increasing G/B for the same H/B. When the detached splitter place was installed, vortices rotating in opposite directions were generated on its upper and lower sides. Reverse flow was caused by the vortices in the wake region of the square prism, and the prism drag was decreased by the reverse flow.     

Multielement stable isotope ratio analysis of glycerol to determine its origin in wine

 The adulteration of wine with glycerol is considered to be a problem in European wine-producing countries. The latest control methods are mainly based on the detection of impurities from commercial products, but suffer from the raising efficiency of the purification processes. As there is little chance of being able to identify glycerol from different sources on the basis of a method which uses only one isotope, a multielement approach was tested. Glycerol from wine showed the lowest relative enrichment with D, mainly in position C-2, a relatively high ¹⁸O content, and very negative δ¹³C values, which significantly correlated with those of ethanol from the same wines. The isotopic data of glycerol samples from different sources were in agreement with those given by indices of origin (impurities). These data allowed us to identify the origin of these glycerol samples, i.e. whether they were produced industrially or synthesised by animals or plants. Glycerol of plant origin was most similar to glycerol found in wine. The combination of several isotopic data by discriminance analysis yielded clusters of data obtained from glycerol samples of similar origin. Taking into account the characteristics of possible mixtures, proof that wine has been adulterated depends on the origin and isotope levels of the added compound. This study showed that it is possible to prove that wine has been adulterated with glycerol from other sources when the latter is present at a concentration of 15% of the total glycerol content. Received: 27 October 1997 / Revised version: 12 February 1998     

Genome-Wide SNP Markers for Genotypic and Phenotypic Differentiation of Melon (Cucumis melo L.) Varieties Using Genotyping-by-Sequencing

Melon (Cucumis melo L.) is an economically important horticultural crop with abundant morphological and genetic variability. Complex genetic variations exist even among melon varieties and remain unclear to date. Therefore, unraveling the genetic variability among the three different melon varieties, muskmelon (C. melo subsp. melo), makuwa (C. melo L. var. makuwa), and cantaloupes (C. melo subsp. melo var. cantalupensis), could provide a basis for evolutionary research. In this study, we attempted a systematic approach with genotyping-by-sequencing (GBS)-derived single nucleotide polymorphisms (SNPs) to reveal the genetic structure and diversity, haplotype differences, and marker-based varieties differentiation. A total of 6406 GBS-derived SNPs were selected for the diversity analysis, in which the muskmelon varieties showed higher heterozygote SNPs. Linkage disequilibrium (LD) decay varied significantly among the three melon varieties, in which more rapid LD decay was observed in muskmelon (r² = 0.25) varieties. The Bayesian phylogenetic tree provided the intraspecific relationships among the three melon varieties that formed, as expected, individual clusters exhibiting the greatest genetic distance based on the posterior probability. The haplotype analysis also supported the phylogeny result by generating three major networks for 48 haplotypes. Further investigation for varieties discrimination allowed us to detect a total of 52 SNP markers that discriminated muskmelon from makuwa varieties, of which two SNPs were converted into cleaved amplified polymorphic sequence markers for practical use. In addition to these markers, the genome-wide association study identified two SNPs located in the genes on chromosome 6, which were significantly associated with the phenotypic traits of melon seed. This study demonstrated that a systematic approach using GBS-derived SNPs could serve to efficiently classify and manage the melon varieties in the genebank.     

Reduction of Biocide-Polluted Wastewater Using O3 and H2O2/O3 Oxidation Processes

The objective of the presented study was to test various oxidation processes with the aim being to reduce the concentration and toxicity of biocide wastewater from a Slovenian phytopharmaceutical factory. Laboratory-scale experiments employing two AOP processes – ozonation (O₃) and peroxone (H₂O₂/O₃) – were applied to reduce the concentration of the active components involved, i.e., methylisothiazolone (MI), chloromethylisothiazolone (CMI) and dichloromethylisothiazolone (DCMI). The reduction of the biocide wastewater load for the performed oxidation processes was evaluated using ecological parameters. The H₂O₂/O₃ oxidation procedure using an O₃ flow rate of 1g/L h, at a pH value of 10 and with the addition of 5 ml of H₂O₂ (0.3 M) proved to be the most effective treatment. The toxicity of the biocide-load wastewater with an initial EC₅₀ = 0.38%, decreased to EC₅₀ (24h) >100% and EC₅₀ (48h) = 76%.     

Numerical analysis for electrokinetic soil processing enhanced by chemical conditioning of the electrode reservoirs

A numerical analysis was undertaken for enhanced electrokinetic soil processing. To perform chemical conditioning of the electrode reservoirs, the electrokinetic soil process employed a membrane as a barrier between the electrode reservoirs and the contaminated soil. An alkaline solution was purged in the anode reservoir that was bounded by the membrane. A mathematical model was used for demonstration of pH change and phenol removal from a kaolinite soil bed, the prediction of pH variations in both electrode reservoirs, and the determination of an optimized injection time of the anode-purging solution. The time-dependent dispersion coefficient was employed in consideration of the averaging effect of the velocity profile on a one-dimensional transport. The estimation of pH and phenol profiles in the soil bed reasonably agreed with the experimental data. The simulation revealed that the removal efficiency of phenol from the kaolinite soil could be improved by maintaining pH of the anode solution.     

Shape control of NITINOL-reinforced composite beams

The shape of composite beams is controlled by sets of flat strips of a shape memory nickel–titanium alloy (NITINOL). The strips are embedded in the composite fabric of these beams inside sleeves, which are placed on the neutral axes. Prior to their insertion inside the beams, the NITINOL strips are thermally trained to provide and memorize controlled transverse deflections. Proper activation of the shape memory effect of the appropriate strips is utilized to produce controlled shapes of the NITINOL-reinforced beams.

A mathematical model is developed to describe the behavior of this class of SMART composites. The model describes the interaction between the elastic characteristics of the composite beams and the thermally induced shape memory effect of the NITINOL strips. The effect of various activation strategies of the NITINOL strips on the shape of the composite beams is determined.

The theoretical predictions of the model are validated experimentally using a fiberglass composite beam made of 8 plies of unidirectional BASF 5216 prepregs, which are 9.75 cm wide and 21.20 cm long. The beams are provided with four NITINOL-55 strips, which are 1.2 mm thick and 1.25 cm wide. The time response characteristics of the beam are monitored and compared with the corresponding theoretical characteristics. Close agreement is obtained between the theoretical predictions and the experimental results. The obtained results suggest the potential of the NITINOL strips in controlling the shape of composite beams without compromising their structural stiffness.     

Design of quaternary Ir-Nb-Ni-Al refractory superalloys

We propose a method for developing new quaternary Ir-Nb-Ni-Al refractory superalloys for ultra-high-temperature uses, by mixing two types of binary alloys, Ir-20 at. pct Nb and Ni-16.8 at. pct Al, which contain fcc/L1₂ two-phase coherent structures. For alloys of various Ir-Nb/Ni-Al compositions, we analyzed the microstructure and measured the compressive strengths. Phase analysis indicated that three-phase equilibria—fcc, Ir₃Nb-L1₂, and Ni₃Al-L1₂—existed in Ir-5Nb-62.4Ni-12.6Al (at. pct) (alloy A), Ir-10Nb-41.6Ni-8.4Al (at. pct) (alloy B), and Ir-15Nb-20.8Ni-4.2Al (at. pct) (alloy C) at 1400 °C; at 1300 °C, three phase equilibria—fcc, Ir₃Nb, and Ni₃Al—existed in alloys A and C and four-phase equilibria—fcc, Ir₃Nb, Ni₃Al, and IrAl-B2—existed in alloy B. The fcc/L1₂ coherent structure was examined by using transmission electron microscopy (TEM). At a temperature of 1200 °C, the compressive strength of these quaternary alloys was between 130 and 350 MPa, which was higher than that of commercial Ni-based superalloys, such as MarM247 (50 MPa), and lower than that of Ir-based binary alloys (500 MPa). Compared to Ir-based alloys, the compressive strain of these quaternary alloys was greatly improved. The potential of the quaternary alloys for ultra-high-temperature use is also discussed.     

Piloting of anionic polymerization of styrene in tetrahydrofurant

Anionic polymerization of styrene in THF with n‐butyllithium/alpha‐methylstyrene initiator is described as a first step in preparation of a styrenic block copoly‐mer. In order to suppress rapid decay of living alpha‐methylstyrene unimers, which occurred at room temperature, the initiation reaction was carried out at ?20(+5)°C. The kinetic parameters of this decay reaction were determined and used for process optimization. By combining experiments with modelling of styrene propagation reaction all key process parameters were defined for l‐L, 38‐L, and 189‐L reactors. A good match was demonstrated between the model and experimental propagation exotherm for semibatch reaction conditions. Overall, it was demonstrated that technical grade THF and styrene could be used at pilot plant scale to prepare well‐defined polymers up to Mn 22 000 via the “living” polymerization mechanism. The resulting polymers had narrow molecular weight distributions (1.06 < Mw/Mn < 1.30).     

Flow and pressure drop characteristics of R22 in adiabatic capillary tubes

The objective of this study is to present flow and pressure drop characteristics of R22 in adiabatic capillary tubes of inner diameters of 1.2 to 2.0 mm, and tube lengths of 500 to 2000 mm. Distributions of temperature and pressure along capillary tubes and the refrigerant flow rates through the tubes were measured for several condensing temperatures and various degrees of subcooling at the capillary tube inlet. Condensing temperatures of R22 were selected as 40, 45, and 50°C at the capillary tube inlet, and the degree of subcooling was adjusted to 1 to 18°C. Experimental results including mass flow rates and pressure drops of R22 in capillary tubes were provided. A new correlation based on Buckingham π theorem to predict the mass flow rate through the capillary tube was presented considering major parameters which affect the flow and pressure drop characteristics.