A numerical investigation of evaporation characteristics of a fuel droplet suspended from a thermocouple

Numerical simulations of combined natural convection–conduction in a droplet of n-dodecane suspended from a thermocouple were carried out, taking into consideration evaporation, and the effect of thermocouple diameter on the evaporation characteristics was investigated. The calculated temperature history of the droplet is in good agreement with experimental results; both show that the rate of heating decreases with increasing thermocouple diameter. The maximum error in temperature due to the thermocouple increases linearly with increasing thermocouple diameter. Thus, in investigations involving a droplet suspended from a thermocouple, it is preferable to use a thermocouple with the smallest possible diameter.     

Effects of rice cleaning and cooking process on the residues of flutolanil,fenobucarb, silafluofen and buprofezin in rice

We studied the effect of cleaning and cooking on the residues of flutolanil, fenobucarb, silafluofen and buprofezin in rice. The rice had been sprayed in a paddy field in Wakayama city, with 3 kinds of pesticide application protocols: spraying once at the usual concentration of pesticides, repeated spraying (3 times) with the usual concentration of pesticides and spraying once with 3 times the usual concentration of pesticides. The residue levels of pesticide decreased during the rice cleaning process. Silafluofen, which has a higher log Pow value, remained in the hull of the rice. Fenobucarb, which has a lower log Pow value, penetrated inside the rice. The residue concentration of pesticide in polished rice was higher than that in pre-washed rice processed ready for cooking. During the cooking procedure, the reduction of pesticides in polished rice was higher than that in brown rice.     

Simple determination of residual anticoccidial drugs (diclazuril and nicarbazin) in chicken tissues by HPLC

A simple and rapid determination of anticoccidial drug residues, diclazuril (DCZ) and nicarbazin (NCZ), in chicken tissues has been developed. DCZ and NCZ were extracted with acetonitrile from chicken liver, muscle, and fat. The extract was rinsed with n-hexane saturated with acetonitrile and then evaporated. The residue was dissolved in 1.4 mL of acetonitrile-methanol (1:1), then 1.0 mL of n-hexane saturated with acetonitrile-methanol (1:1) was added, and the mixture was partitioned by the addition of 0.6 mL of water. DCZ and NCZ in the aqueous layers were determined by HPLC on an Xterra RP-18 column with acetonitrile-0.5% ammonium acetate containing 0.01 mol/L tetra-n-butylammonium hydrogen sulfate (43:57) as the mobile phase. The mean recoveries (n = 5) of DCZ and NCZ spiked in chicken tissues at the maximum residue levels were 92.0-95.6% (CV 2.4-3.0%) and 87.3-89.4% (CV 1.7-2.8%), respectively. The detection limits of DCZ and NCZ were 0.01 and 0.004 microgram/g, respectively.     

Synthesis and crystal structure analysis of complex hydride Mg(BH4)(NH2)

Complex hydride Mg(BH₄)(NH₂), which consists of double anion BH₄⁻ and NH₂⁻, was synthesized and the crystal structure was analyzed by synchrotron X-ray diffraction. The mixture sample of Mg(BH₄)₂ + Mg(NH₂)₂ prepared by ball milling was reacted and crystallized to Mg(BH₄)(NH₂) by heating at about 453 K. This crystal phase transforms into amorphous phase above 473 K and subsequently the dehydrogenation begins. The crystal structure of Mg(BH₄)(NH₂) was determined from measurement data at 453 K (chemical formula: Mg_0.94(BH₄)₁(NH₂)_0.88, crystal system: tetragonal, space group: I4₁ (No.80), Z = 8, lattice constants: a = 5.814(1), c = 20.450(4) Å at 453 K). Mg(BH₄)(NH₂) is ionic crystal which the cation (Mg²⁺) and the anions (BH₄⁻ and NH₂⁻) are stacking alternately along the c-axis direction. Two BH₄⁻ and two NH₂⁻ tetrahedrally coordinate around Mg²⁺ ion.     

Development of effective detection method for Coxiella burnetii in mayonnaise by real-time PCR and investigation of C. burnetii contamination in commercial mayonnaise in Tokyo

A PCR method for the effective detection of Coxiella burnetii in commercially available mayonnaise was developed. Sample preparations were isolated from 50 g portions of each mayonnaise product by four successive extraction steps in phosphate buffer with 2.0 M NaCl. These extracts were then centrifuged at 20,000 x g for 60 min. DNA was isolated from the solution containing the precipitate with a commercial kit, and amplified quantitatively using real-time PCR that targeted the com1 region of C. burnetii. The recoveries of C. burnetii from 2 kinds of commercial mayonnaise specimens, with a baseline control of 1 x 10(7) particles of the Nine Mile phase II strain, were 85.0 +/- 6.0% and 72.0 +/- 0.4%, respectively. The determination limit of this method was 500 C. burnetii particles per 50 g of mayonnaise. The DNA specimens isolated from 50 different commercial mayonnaise samples sold in Tokyo using this method were amplified using both nested PCR and real-time PCR. No contamination by C. burnetii was detected in any of the mayonnaise samples.     

Effect of gaseous ammonia on barley straws showing different rumen degradabilities

Straw samples from five cultivars of spring barley (Hordeum vulgare L; Golden Promise, Golf, Klaxon, Heriot and Doublet), selected to show a range of rumen degradabilities, were examined to measure the effect of gaseous ammonia on aspects of their cell wall composition and degradability after treatment. Cellulose degradability of the untreated straws, as measured by the nylon-bag method, ranged from 41.0% for Golden Promise to 57.1% for Doublet. The extent of improvement in degradability following ammonia treatment was 12.5% units for Golden Promise and only 2.5% units for Doublet, showing that the effect of ammonia was more pronounced for materials of lower inherent degradability (r= ?0.774). Straw from three of the five cultivars was dissected into its botanical parts, and the dry matter content and digestibility of the fractions were determined. Leaf material formed a higher fraction of dry matter in Doublet (0.48), the most degradable cultivar, than in Golden Promise (0.30), the least degradable straw. Half of the observed difference in degradability between Doublet and Golden Promise could be attributed to differences in dry matter distribution between botanical fractions. For untreated straw, degradability was weakly, negatively correlated with the proportion of arabinose residues substituted with alkali-labile linkages at position 0–5 (r = ?0.690), and positively correlated with the moisture retention (water-holding capacity) of straws (r = 0.838), water-soluble dry matter content (r = 0.922) and water-soluble phenolic content (r = 0.791). The proportion of pentose residues carrying alkali-labile linkages was only slightly decreased followign ammonia treatment. In the case of the 0–5 position of arabinose residues the original values were reduced by 2.4–15.9%. Ammonia treatment had little effect on the capacity of the straw to retain moisture, and did not significantly increase the proportion of water-soluble dry matter or phenolics. Cellulose degradability, or the improvement in degradability, of ammonia-treated straw was not correlated with any of the physical and chemical characteristicds of staw considered above.     

Mercury oxidation by hydrochloric acid over TiO2 supported metal oxide catalysts in coal combustion flue gas

Mercury oxidation by hydrochloric acid over the metal oxides supported by anatase type TiO₂ catalysts, 1 wt.% MO_x/TiO₂ where M = V, Cr, Mn, Fe, Ni, Cu, and Mo, was investigated by the Hg⁰ oxidation and the NO reduction measurements both in the presence and absence of NH₃. The catalysts were characterized by BET surface area measurement and Raman spectroscopy. The metal oxides added to the catalyst were observed to disperse well on the TiO₂ surface. For all catalysts studied, the Hg⁰ oxidation by hydrochloric acid was confirmed to proceed. The activity of the catalysts was found to follow the trend MoO₃ ~ V₂O₅ > Cr₂O₃ > Mn₂O₃ > Fe₂O₃ > CuO > NiO. The Hg⁰ oxidation activity of all catalysts was depressed considerably by adding NH₃ to the reactant stream. This suggests that the metal oxide catalysts undergo the inhibition effect by NH₃. The activity trend of the Hg⁰ oxidation in the presence of NH₃ was different from that observed in its absence. A good correlation was found between the NO reduction and the Hg⁰ oxidation activities in the NH₃ present condition. The catalyst having high NO reduction activity such as V₂O₅/TiO₂ showed high Hg⁰ oxidation activity. The result obtained in this study suggests that the oxidation of Hg⁰ proceeds through the reaction mechanism, in which HCl competes for the active catalyst sites against NH₃. NH₃ adsorption may predominate over the adsorption of HCl in the presence of NH₃.     

Topical Phenomena Observed in a Short-Gap Atmospheric Discharge Using Rotor and Post Electrodes

Correlation of light emission, discharge structure, waveform of the discharge current, electrode configuration, and electromagnetic radiation is examined with the intent of obtaining an effective means for preventing electromagnetic interference (EMI) due to a short-gap discharge. The electromagnetic radiation (EMR) level resulting from a current step which, in turn, was formed by a discrete movement of a cathode spot was clearly recognized. A combination of needle rotor and needle post gave the smallest electromagnetic radiation level in the experiments.     

Phase study on solid fission products,Ba, Sr and Zr in oxide fuel

Behavior of pseudo-fission products (Ba, Sr, and Zr) as oxides in UO₂ has been investigated by means of high-temperature X-ray diffraction and microprobe analysis. Two identifiable compounds were formed as reaction products in the mixed oxides which initially consisted of UO₂, BaO, SrO, and ZrO₂ powder. These compounds were present and were identified crystallographically as (Ba, Sr) ZrO₃ and (Ba, Sr)UO₃ after heat treatment of the powders at 1500°C for 30 min. Both compounds are isostructural with perovskite, CaTiO₃, and the lattice parameters of both (Ba, Sr)ZrO₃ and (Ba, Sr)UO₃ decrease with increasing content of Sr. (Ba, Sr)UO₃ is decomposed almost completely at 1800°C while (Ba, Sr) ZrO₃ is stable up to 2000°C. The behavior of Ba, Sr, and Zr in fuel under irradiation is discussed.     

Rheological interpretation of heat generation associated with fatigue of polycarbonate

Temperature change was measured of polycarbonate under monotonically increasing tensile and pulsating tensile loads. In the former case, the specimen temperature began to rise when an appreciable amount of viscoelastic strain was noticed on the stress—strain diagram. The rise, θ_v, could be formulated as a function of the viscoelastic strain, εv: In fatigue tests, the average temperature began to rise immediately after the decrease due to the thermoelastic effect. The amount of the heat generation, σ, was nearly constant for each cycle throughout the fatigue process and has a relation to the fatigue life, N_f, (α? a)·N_f = constant, where a is another adjustable constant. From a rheological aspect of dissipation energy, the equation is transformed to a relation between the viscoelastic strain and the fatigue life as εV^1/2 · N_f = constant, which is similar to the one for metals given by Manson and Coffin.⁶ The temperature rise in the fatigue was also related to the viscoelastic strain. The relation is of the same form as for static tension but less by a factor of one order.