Cause–effect analysis on Fukushima accident reports – What did McMaster undergraduate students learn?

In the ENG PHYS 4ES3 Course “Special Topics in Energy Systems (2014–2015)” in McMaster University, sixteen 4th-year undergraduate students studied the Fukushima accident, discussed the causes of accident and its impacts on the energy systems from the sustainability point of view, made the oral presentation and submitted the reports. In this paper, a cause–effect and causal-loop analysis was applied to the discussion in the reports, the diagram of cause–effect relationship was drawn, and the important problems were extracted from the diagram. It was found that the important problems and the diagram of cause–effect relationship McMaster undergraduate students considered were similar to the essential problems and the diagram Horii pointed out, although Interim Report of the Investigation Committee on the Accident at Fukushima Nuclear Stations of Tokyo Electric Power Company which Horii used was not adopted in the reports submitted by students.     

Structure and kinetic studies of U(VI)-benzamidoxime complex in non-aqueous solutions by H- and C-NMR

The structural and kinetic studies of U(VI) complex with benzamidoxime(Hba) as ligand in CD₃COCD₃ have been studied by means of ¹H and ¹³C NMR. The Hba molecule was found to coordinate to UO₂²⁺ in the form of anionic benzamidoximate (ba), and the number of ba coordinated to UO₂²⁺ was determined to be 3 by analyzing the chemical shift of ¹³C NMR signal for Hba in the presence of UO₂²⁺. The exchange rate constants(k_ex) of ba in [UO₂(ba)₃] were determined by the NMR line-broadening method. The kinetic parameters were obtained as follows: k_ex(25°C) = 3.1 × 10³s⁻¹, ΔH^≠ = 35.8 ± 3.5 KJ mol⁻¹, and ΔS^≠ = −65 ± 13.7 J K⁻¹ mol⁻¹. The UV-visible absorption spectra of solutions containing UO₂²⁺ and Hba were also measured. The molar extinction coefficient of the complex was found to be extremely large compared with those of UO₂(L)₅²⁺ (L = unidentate oxygen donor ligands) complexes. This is due to the strong electron withdrawing of UO₂²⁺ from Hba and suggests that an interaction between UO₂²⁺ and Hba is very strong. Such a high affinity of monomeric amidoxime to UO₂²⁺ reasonably explains the high adsorptibility of amidoxime resin to U(VI) species, and is considered to result in the high recovery of U(VI) species from sea water using amidoxime resin.     

Ultrastrong Medium‐Entropy Single‐Phase Alloys Designed via Severe Lattice Distortion

Severe lattice distortion is a core effect in the design of multiprincipal element alloys with the aim to enhance yield strength, a key indicator in structural engineering. Yet, the yield strength values of medium‐ and high‐entropy alloys investigated so far do not substantially exceed those of conventional alloys owing to the insufficient utilization of lattice distortion. Here it is shown that a simple VCoNi equiatomic medium‐entropy alloy exhibits a near 1 GPa yield strength and good ductility, outperforming conventional solid‐solution alloys. It is demonstrated that a wide fluctuation of the atomic bond distances in such alloys, i.e., severe lattice distortion, improves both yield stress and its sensitivity to grain size. In addition, the dislocation‐mediated plasticity effectively enhances the strength–ductility relationship by generating nanosized dislocation substructures due to massive pinning. The results demonstrate that severe lattice distortion is a key property for identifying extra‐strong materials for structural engineering applications.     

Mutants of the nematode Caenorhabditis elegans that are defective specifically in their attraction to cycloheximide

The nematode Caenorhabditis elegans exhibits chemotaxis toward a wide variety of chemicals including water-soluble molecules and volatile organic compounds. We have previously discovered that C. elegans wild-type strain N2 is strongly attracted by cycloheximide which has long been known as a bitter tastant for humans and other mammals. We describe here the isolation and initial characterization of the first mutants which were defective specifically in their attraction to cycloheximide. In our screenings, we selected two mutants that were defective in chemotaxis to cycloheximide but normal in their attraction to NH4Cl and histidine. These mutants also avoided quinine hydrochloride, CuSO4 and high concentrations of NaCl similar to the wild-type strain N2. Furthermore, no observable defect was detected in their attraction to volatile odorants such as isoamyl alcohol and diacetyl. Dye-filling experiments suggested that they have no morphological defect in the sensory endings of the amphid neurons.     

A convenient method for the evaluation of anti-tumor agents affecting the cell cycle

Mitotic index (MI), defined as the ratio (%) of the mitotic-phase-arrested cell number to the total cell number, is higher in the presence of colcemid than in its absence. MI is reduced by anti-tumor agents used in conjunction with colcemid. The ratio of MI, which is defined by the dose of colcemid to that of the supplement with etoposide as an anti-tumor agent and is designated MIR, was 10% at an exposure of 2 h, suggesting that etoposide blocks the cell cycle before 2 h of the mitotic phase. Thus, we established a convenient method to identify a target point in the cell cycle for anti-tumor agents using colcemid. RBL-2H3, a mammalian cell line, exhibited a large number of 2-fold swollen nuclear envelopes after exposure to etoposide. The G2-index, which is the ratio of the number of swollen nuclei to the total number of nuclei, was higher when the cells were incubated with etoposide than without it. In this study, we suggest that the measurement of the G2-index contributes to the screening of putative anti-tumor agents.     

Rheological properties and stability of oil-in-water emulsions containing tapioca maltodextrin in the aqueous phase

The present research focuses on the effect of the concentration and dextrose equivalent (DE) values of tapioca maltodextrin in the aqueous phase on rheological behavior and stability of oil-in-water emulsions prepared with Tween80. The critical flocculation concentrations (CFCs) of oil-in-water emulsions containing tapioca maltodextrin with DE of 16 (DE16), 12 (DE12) and 9 (DE9) were 11%, 9% and 7% (w/w) respectively, as revealed by transmittance measurement. Coalescence was observed as maltodextrin concentration increased above the CFC. The rheological parameters of flow behavior index (n) and consistency index (k) have been well-described by the Herschel–Bulkley model. The relative consistency index (k_relative) increased markedly when the concentration of maltodextrin exceeded the CFC because of depleting flocculation. The consistency index (k_emulsion) and yield stress (τ₀) of emulsions containing tapioca maltodextrin increased with increasing maltodextrin concentration or decreasing DE. The emulsions containing maltodextrin showed Newtonian flow behavior when the maltodextrin concentration was below the CFC. At maltodextrin concentrations above the CFC, emulsions containing maltodextrin exhibited shear thinning behavior. An increase in the maltodextrin concentration resulted in a decrease in the n_emulsion until maltodextrin concentration reached 20% (w/w) for DE9, DE12 and 25% (w/w) for DE16. Further increase in the maltodextrin concentration resulted in an increased the n_emulsion because of predominant influence of the continuous phase.     

Diagnostics of TM010-mode microwave cavity discharges inCO2-N2-He laser gas mixtures. II. Measurement ofvibration temperature

For pt. I see ibid., vol., 31, no. 8, p. 1525-32 (1995). The plasma temperatures in microwave discharged CO₂-N₂-He laser gas mixtures were examined using the spectroscopic and electrostatic probe methods. A vibration temperature of N₂ molecules, obtained spectroscopically, was determined to be nearly 7000 K without gas circulation and to be nearly 4000 K at the mass flow rate of 4.2 kg/h. It is found that an efficiency of laser output power exceed 14% (RF to laser output power conversion ratio) below the vibration temperature of 4000 K. The values of vibration temperature obtained were higher than those reported in DC discharges