Heavy Lake-Effect Snowfall Changes and Mechanisms for the Laurentian Great Lakes Region

Heavy lake-effect snowfall (HLES) events are snowfall events enhanced by interactions between lakes and overlying cold air. Significant snowfall rates and accumulations caused during such events disrupt socioeconomic activities and sometimes lead to lethal consequences. The aim of this study is to assess projected changes to HLES by the end of the century (2079–2100) using a regional climate model for the first time with 3D representation for the Laurentian Great Lakes. When compared to observations over the 1989–2010 period, the model is able to realistically reproduce key mechanisms and characteristics of HLES events, thus increasing confidence in future projections. Projected changes to the frequency and amount of HLES suggest decreasing patterns, during the onset, active and decline phases of HLES. Despite reduced lake ice cover that will allow enhanced lake–atmosphere interactions favouring HLES, the warmer temperatures and associated increase in liquid to solid precipitation ratio along with reduced cold air outbreaks contribute to reduced HLES in the future climate. Analysis of the correlation patterns for current and future climates further supports the weaker impact of lake ice fraction on HLES in future climates. Albeit the decreases in HLES frequency and intensity and projected increases in extreme snowfall events (resulting from all mechanisms) raise concerns for impacts on the transportation, infrastructure and hydropower sectors in the region.

Improvement of Organic Soil Shear Strength through Calcite Precipitation Method Using Soybeans as Bio-Catalyst

Organic soil has a high content of water and compressibility. Besides that, it has a low specific gravity, density, and shear strength. This study evaluates the applicability of the soybean crude urease for calcite precipitation (SCU-CP) method and its effectiveness in organic soil as a soil-amelioration technique. Various soybean concentrations were mixed with a reagent composed of urea and calcium chloride to produce the treatment solution. Its effect on the hydrolysis rate, pH, and amount of precipitated calcite was evaluated through test-tube experiments. SEM-EDS tests were performed to observe the mineralogy and morphology of the untreated and treated samples. The treatment solution composed of the reagent and various concentrations of soybeans was applied to organic soil. The increasing strength of the organic soil was evaluated using direct shear (DS) and unconfined compression (UCS) tests. The test-tube results show that a hydrolysis rate of 1600 u/g was obtained when using 50 g/L of soybeans with a precipitation ratio of 100%. The mechanical tests show a significant enhancement in the parameters of the organic soil’s shear strength. A shear strength improvement of 50% was achieved in this study. A UCS of 148 kPa and cohesion of 50 kPa was obtained in the treated samples of organic soil. This research elucidates that the SCU-CP is an effective technique for improving organic soil’s shear strength.

The geostatistical analysis of the atmospheric precipitation in Europe on a West-East line transect

The general warming trend of the planet cannot be denied (the average global air temperature has increased by approx. 0.85°C between 1880-2012 (IPCC, 2013). The direct consequence of this warming is an increase in extreme weather events and hence in climate risks. The monitoring and assessing precipitation, identifying the physical laws governing its course in order to be able to estimate and forecast it in the future is therefore of great interest nowadays. Using geostatistical spatial analysis methods, this paper aims at identifying the correlations between longitude and precipitation (due to the specificity of the European climate, given by the major influence of the western circulation) and then an estimation - using linear regression equations - of precipitation amounts depending on longitude. Two variables were calculated for the statistical analysis: the proportion of the mean number of days with precipitation ≥ 10 mm of the multiannual mean of precipitation days (≥0,1 mm) and the precipitation ratio between the mean precipitation quantities in summer, compared to those in winter (hereinafter referred to as summer/winter precipitation ratio). The geostatistical analysis carried out on a sample of 40 weather stations aligned from west-south-west to east-north-east argues the existence of a strong correlation between longitude and the multiannual mean of days with precipitation ≥10 mm and between longitude and the summer/winter precipitation ratio.

Efficient Separation of Silicon and Vanadium by Sodium Roasting-Water Leaching from Vanadium Slag and CaV2O6 Preparation

Calcium vanadate (CaV2O6), a new product of vanadium precipitation, was obtained from vanadium slag by sodium roasting-water leaching and calcium precipitation. The separation behavior of vanadium and silicon in vanadium slag during sodium roasting and water leaching was systematically studied, and micro-morphology and valence migration behavior of vanadium and Fe in vanadium slag, roasting slag, and residue were revealed. The Na2CO3 was added to the vanadium slag at 20% mass fraction, roasted at 790 ℃, and kept for 120 min, the roasted sample was added to the deionized aqueous solution with a liquid-solid ratio of (L/S) 5mL/g, and then heated at 90 ℃ for 60 min, 89.54% vanadium and 1.96% chromium were extracted. Sodium carbonate tends to combine with vanadium to form sodium vanadate, while silicon is easy to combine with Fe and Na to form acmite (NaFeSi2O6). When the molar ratio of N (Ca/V) is 0.6 and CaO, is added to adjust the pH of vanadium leaching solution to 6.7 ± 0.1 and precipitate 90 min at 90 ℃, vanadium is precipitated in the form of CaV2O6 with a purity of 95.69%, under these conditions, the precipitation ratio is 95.03%.

Influence of Al and N Content and Cooling Rate on the Characteristics of Complex MnS Inclusions in AHSS

This study focused on the characteristics of complex MnS inclusions in advanced high strength steels. The effect of metal chemistry (Al and N) and the cooling rate of steel were evaluated by analyzing the inclusions present in five laboratory produced steels. The observed complex MnS inclusions contained Al2O3-MnS, AlN-MnS, and AlON-MnS. An increase in Al content from 0.5% to 6% increased the number of complex MnS inclusions by ~4 times. In comparison, a decrease of ~80% was observed due to the increased N content of steel from <10 ppm to ~50 ppm. MnS precipitation ratio was used to determine the potency of different inclusions forming complex MnS inclusions due to heterogeneous nucleation. It was found that the MnS precipitation ratio of the observed inclusions was related to their misfit with MnS, and it decreased in the order of AlN > AlON > Al2O3. Moreover, it was determined that AlN particles could be easily engulfed at the solidification front relative to Al2O3, which resulted in a higher MnS precipitation ratio for Al2O3 under slow cooling conditions.

SAT-426 Macro-Thyroid Stimulating Hormone (TSH) in Children

Macro-TSH is mainly a complex of TSH with anti-TSH autoantibodies. Due to its large molecular size (&gt;150 kDa), it accumulates in the circulation resulting in elevated serum TSH concentrations. Because the bioactivity of macro-TSH is low, treatment with thyroxine is not necessary. The prevalence of macro-TSH is no more than 1% in adult patients with subclinical hypothyroidism. However, the prevalence of macro-TSH in children is not known. We report here two cases of macro-TSH in pediatric setting. [Case reports] Case 1. Six-year and eight-month-Japanese boy visited a pediatric hospital because of hyperactivity disorder. Physical examination revealed that he had a slight mental retardation (IQ 63 by Tanaka-Binet test). Thyroid tests showed that fT4 1.21 ng/dL, TSH 120.4 µU/mL, Tg antibody 1.9 IU/mL, TPO antibody &lt;0.1 IU/mL. His serum was sent to our laboratory to examine the causes of inappropriate high serum TSH concentration. Case 2. Eight-year and three-month-Turkish girl was brought to a pediatric hospital by her parents because of her yellowish palms, which was not identified at the hospital. She did not have any complaints and physical signs attributable to thyroid dysfunction. Laboratory data disclosed that fT4 1.5 ng/dL, TSH 19.6 µU/mL, Tg Ab negative, TPO Ab negative. Levothyroxine treatment started but serum TSH concentration was still high (39.0 µU/mL) after two months. Her serum sample was sent to our laboratory to examine the causes of inappropriate high serum TSH concentrations. [Lab. Tests for macro-TSH] When serum was mixed with the same amount of 25% polyethylene glycol (PEG) and γ-globulin fraction was precipitated, TSH concentration in the supernatant decreased significantly from 109.3 µU/mL to 2.3 µU/mL (PEG precipitation ratio 97.9%) in case 1, and from 17.3 µU/mL to 0.15 µU/mL (PEG precipitation ratio 99.1%) in case 2. HAMA blockers did not significantly change TSH concentration in both cases. High proportion of serum TSH bound to a protein G column, which binds IgG, in case 1 (91.3%) and in case 2 (57.7%), indicating that TSH was associated with IgG. Gel filtration chromatography (GFC) revealed that TSH was mostly eluted at the fraction &gt; 150 kDa rather than 28 kDa of authentic TSH in both cases. Serum was incubated with 37.7 µU of TSH for one hour and subjected to GFC. TSH concentration in the fraction of 150 kDa (macro-TSH) increased from 2.8 µU/mL to 5.6 µU/mL in case 1 and from 0.4 µU/mL to 2.0 µU/mL in case 2, suggesting that macro-TSH was produced by the binding of exogenous TSH to anti-TSH autoantibodies. [Conclusion] Macro-TSH exists in children and careful evaluation is required in patients with inappropriate high serum TSH concentrations to avoid unnecessary treatment.