Spatial and temporal variations in water temperature in a high-altitude deep dimictic mountain lake (Nam Co), central Tibetan Plateau

Water temperature and the related thermal structure and stratification of a lake are very important to lake ecosystems because of their significant effects on the vertical exchanges of dissolved and particulate matter. In this study, we present high resolution, seasonal variations in water temperature at different depths of a large deep lake on the central Tibetan Plateau. The results show that Nam Co is a typical dimictic lake whose thermal stratification begins and ends in early June and early November, respectively. Increases in the water temperature during spring and the establishment of thermal stratification in the eastern small sub-basin occur approximately one month prior to the main basin which is likely caused by the different morphometry, different water transparency during spring, and the possible presence of a spring thermal bar. The Schmidt stability of the water column is directly controlled by surface water temperature. During the ice-covered period, the homogeneous water temperature exhibits a continuous increasing trend from approximately 0.5 °C to 3.5 °C. The daily mean surface water temperature of the main open lake area is highly correlated to the air temperature but shows a hysteresis effect of approximately 38 days, which shows the significant heat storage in such a large deep lake. Nam Co is a typical lake in this area in terms of its altitude, water depth and climatic conditions, so our results have broader significance for limnological and paleolimnological studies of similar lakes on the Tibetan Plateau.     

Development of reduced saturated fat cookie fillings using multicomponent oleogels

Cookie fillings are typically composed of sugar (60%–80%) and fat (20%–40%). The fat in these fillings is known as shortening, which currently has high levels of saturated fatty acids (SFA) and, in some cases, trans fatty acids (TFA). This makes the nutritional profile of this product a reason for concern, especially considering that the target audience for cookies is children. This study thus aimed to replace the commercial shortening in these fillings with oleogels made of soybean oil (SB) and high oleic sunflower oil (SF) structured with candelilla wax (CLX), monoglycerides (MG), and hard fat (HF), in different concentrations ranging from 5%–10% of the total structuring content. The complete replacement of shortening with oleogel reduced the amount of TFA by 100% and the amount of SFA by 50%–80%. The quantities of MG and HF greatly influenced the structuring of the product because the higher the concentrations (≥3%), the better the formation of the structured network, with good aeration, greater hardness, and less oil loss, compared with the standard with shortening. The samples that achieved physical properties similar to those of the control sample were samples 3:3:3 and 1:4:5 (CLX:MG:HF). These showed similar oil loss at T0 (~4.5%), and microstructure before and after temperature oscillations and closer consistency (~400 gF/cm²) and adhesiveness (50 gF. s) to the RP (800 gF/cm² and 75 gF. s). Although MG and HF are not good structuring elements alone as the CLX, they formed a network that is connected by hydrogen bonds with the sugar molecules that were resistant to stirring and thermal changes, which makes this system a potential replacement for shortenings in cookie fillings application.     

Study of complexing reactions causing the depletion of gadolinium ions from the moderator of CANDU-PHW nuclear reactors

The addition of gadolinium nitrate solution in the moderator of Hydro-Québec's Gentilly 2 reactor led to an unexpected depletion of gadolinium (Gd) by precipitation. Analysis of moderator samples revealed that bicarbonate (HCO₃^?) was the main anionic impurity. A study of the complexing reactions of Gd in concentrated solutions (0.0509M) of Gd(NO₃)₃ showed that in the absence of HCO₃^? and at pH < 6, the species in equilibrium are distributed as follows: predominant: Gd³⁺, NO₃^? and [GdNO₃]²⁺; and traces: [GdOH]²⁺ and [Gd(NO₃)₂]⁺. An increase in pH over 6.4 led to the formation of the solid phase: Gd₂(OH)_5.1(NO₃)_0.9. In the presence of bicarbonate, the solid phase Gd₂(OH)_5.0(NO₃)_1.0 is visually detected at a pH as low as 5.8. In other respects, analysis of dilute solutions (0.00065M) of Gd(NO₃)₃ containing bicarbonate allows the solid phase precipitating between pH 5.5 and 6.6 to be ascribed to the formula Gd₂(OH)₄CO₃·3H₂O. In the absence of HCO₃^?, no precipitation occurred up to pH 6.8. Finally, the loss of Gd from the moderator was established as being due to the formation of a hydroxide carbonate salt.     

Intermediates and isomers in the substitution of cobalt carbonyl hydride with tertiary phosphorous ligands

Mono- and disubstitution of HCo(CO)₄ with tertiary phosphines and phosphites was studied by IR and¹H-NMR spectroscopy. It was found that these substitutions proceed through phosphonium tetracarbonylcobaltate intermediates, leading to a mixture of isomers. The crystal and molecular structure of trans-HCo(CO)₃[P(O-p-C₆H₄Ph)₃] was determined by X-ray diffraction.GDR research fellow at the University of Veszprém.     

Reinforcing, subjective, and performance effects of lorazepam and diphenhydramine in humans.

The reinforcing. subjective. and performance effects of 400 mg diphenhydramine (D), 4 mg lorazepam (L), and placebo (P) were compared across repeated administrations in 12 healthy, adult male participants with histories of recreational sedative abuse. P, L, and D were administered orally in a block, random sequence 4 times each. L and D increased scores on participants liking of the drug, desire to take the drug again, and monetary value of the drug relative to placebo. D increased ratings on scales of unpleasant somatic side effects. When the choice was between D and P or between L and P, choice between D and L was greater than chance, and choice of P was less than chance. When the choice was between D and L, both drugs were chosen an equal number of times. L and D effects were consistent across repeated administrations. Correlational analysis showed that some subjective measures were positively correlated, whereas other measures were negatively correlated with measures of drug reinforcement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Gene dosage effects in hereditary peripheral neuropathy. Expression of peripheral myelin protein 22 in Charcot-Marie-Tooth disease type 1A and hereditary neuropathy with liability to pressure palsies nerve biopsies

A duplication of a 1.5-Megabase genomic region encompassing the gene for the peripheral myelin protein 22 (PMP22) is found on chromosome 17p11.2-12 in Charcot-Marie-Tooth disease type 1A (CMT1A), whereas the reciprocal deletion is associated with hereditary neuropathy with liability to pressure palsies (HNPP). Since most CMT1A patients harbor three copies of the PMP22 gene, and most HNPP patients carry only a single copy, a gene dosage effect has been proposed as a mechanism for both diseases. We have analyzed the steady-state expression of PMP22 protein in sural nerve biopsies from three CMT1A and four HNPP patients. Quantitative immunohistochemical determination showed that PMP22 protein expression relative to that of myelin protein zero and myelin basic protein was increased in all CMT1A patients and reduced in all HNPP patients, as compared with biopsy samples of patients with normal PMP22 gene expression. These data demonstrate that both neuropathies result from an imbalance of PMP22 protein expression.     

STEAM DRYLNG OF WOOD FUELS

The objective of this work is to investigate some of the important aspects in the design of a steam band dryer for wood fuels. For this purpose the drying of the material in a bench-scale fixed bed dryer has been studied.

Drying times and thermal efficiencies for experiments conducted under different conditions are compared. The investigated materials are soft-and hardwood chips and softwood bark.

The thermal efficiency, the part of the sensible heat which is used during one passage of the steam through the bed, increases with increasing mass load (mass of dry matter per unit area) and with decreasing steam mass flux. At a mass load of 30 kg/m the thermal efficiency is about 0.85 even at steam mass fluxes as high as 0.6 kg/m² s (1.2 m/s). The thermal efficiency proves to be almost independent of pressure and temperature of the steam.

Due to the very inhomogeneous materials the steam mass flow distribution was uneven. This causes a decreased thermal efficiency. When bark     

Mesoporous carbon-containing MoS2 materials formed from the in situ decomposition of tetraalkylammonium thiomolybdates

Molybdenum disulfide with unique mesoporous structure was synthesized from tetraalkylammonium thiometallate precursors in situ decomposed in a batch reactor in the presence of dibenzothiophene (DBT). The precursors used in this study were tetraalkylammonium thiomolybdates with alkyl groups ranging from propyl to octyl. Molybdenum disulfide thus prepared presents high surface area (from 255 up to 329 m²/g), high content of carbon (C/Mo=2.7-4.0) and type IV nitrogen adsorption-desorption isotherms when decomposed from tetrahexyl-, tetraheptyl- or tetraoctylammonium thiomolybdates. The as-formed materials are poorly crystallized with a very weak intensity of the (0 0 2) peak of the 2HMoS₂ structure. Such diffraction patterns are characteristic of exfoliated samples. Characterization by TEM shows a disordered layered structure with no long range order for the MoS₂ catalysts. Therefore, the nature of the alkyl group in the precursor affects both the surface area and the pore size distribution of the final MoS₂ catalysts with a progressive morphological modification up to a mesoporous organization.     

Material property database for heat treatment simulation of tool materials

A materials data base has been set up with mechanical, thermophysical and transformation properties of tool and creep resistant steels. In particular powder metallurgical materials have been covered. The intended use of the data is for numerical simulation of heat treatment with focus on computation of residual stresses and distortion in Compound materials (macro composites). The main body of the data was generated in new experiments. In this paper data for the powder metallurgical high speed steel ASP 2060 will be presented. The material properties determined include thermophysical data such as thermal conductivity and specific heat, mechanical data such as yield strength and work hardening rate, and thermal expansion data. Most data were determined at different temperatures and after heat treatments to different microstructures. Additional data added to the database include literature data for elastic properties and transformation induced plasticity. Quenching of a Compound ring consisting of an inner high speed steel and an outer tool steel was simulated numerically using two codes, DistSIMR and Trast7. With the help of a database interface input data adjusted to the formats of the two codes were generated. The results of the simulations showed good agreement between the two models both for the computed residual stresses and distortions, which confirms the reliability of the results.