Study on Synthesis and Service Properties of Anticoagulant Ice Microcapsule Coating Material

The presence of ice and snow on a road surface in winter will reduce the traffic capacity of the road network, which can easily lead to traffic accidents. In this study, nonchlorine organic snow-melting salt was added to emulsified asphalt to prepare an anticoagulant ice fog seal. Considering the destructive effect of snow-melting salt on the stability of emulsified asphalt, polyvinyl alcohol was used as an encapsulation material to form a stable two-phase system by mixing snow-melting salt with emulsified asphalt. The zeta potential method was used to test the storage stability of the encapsulated salt solution. The results showed that the material and content of the encapsulation had a significant effect on the stability of the emulsified asphalt and the reduction in the freezing point of the encapsulated salt solution. PVA (1.5%) mixed with 24% sodium acetate was used to prepare an encapsulated salt emulsion, which was mixed with anionic emulsified asphalt and sprayed on the road surface. This significantly reduced the freezing point of road surface water. The recommended spraying dosage of the anticoagulant ice fog seal layer was 0.4 kg/m2, which could lower the freezing point by at least −8°C while simultaneously meeting the antislip performance condition. This was shown to be a preventive maintenance technology with both anticoagulant ice and maintenance effects.

Ice fog monitoring near Fairbanks, AK

Ice fog events, which occur during the Arctic winter, result in greatly decreased visibility and can lead to an increase of ice on roadways, aircraft, and airfields. The Fairbanks area is known for ice fog conditions, and previous studies have shown these events to be associated with moisture released from local power generation. Despite the identified originating mechanism of ice fog, there remains a need to quantify the environmental conditions controlling its origination, intensity, and spatial extent. This investigation focused on developing innovative methods of identifying and characterizing the environmental conditions that lead to ice fog formation near Fort Wainwright, Alaska. Preliminary data collected from December 2019 to March 2020 suggest that ice fog events occurred with temperatures below −34°C, up to 74% of the time ice fog emanated from the power generation facility, and at least 95% of ice particles during ice fog events were solid droxtals with diameters ranging from 7 to 50 μm. This report documents the need for frequent and detailed observations of the meteorological conditions in combination with photographic and ice particle observations. Datasets from these observations capture the environmental complexity and the impacts from energy generation in extremely cold weather conditions.

Comparison of Techniques to Control Ice Nucleation during Lyophilization

Controlling ice nucleation during lyophilization of parenteral drug products increases the homogeneity of critical quality attributes, such as residual moisture, across drug product batches and shortens lyophilization cycle time. In the present study, we compare three mechanistically different techniques to control ice nucleation during the freezing step of lyophilization, which are referred to as “depressurization”, “partial vacuum”, and “ice fog” techniques. The techniques are compared with respect to their operational limitations and challenges. Installation considerations are also discussed. Using the aforementioned nucleation techniques, we investigated a monoclonal antibody formulation and an enzyme formulation at different protein concentrations using feasible nucleation temperatures and different vial formats and fill volumes. Samples were compared for solid state properties and other critical quality attributes on stability. When nucleated at the same temperature, the three techniques produced products with the same quality attributes and stability behavior. Under conditions resulting in micro-collapse, stability behavior can be different. We found that each technology had considerations for achieving robust nucleation. The present comparison may serve as guidance in selecting a nucleation method.

Changes in Fog, Ice Fog, and Low Visibility in the Hudson Bay Region: Impacts on Aviation

Fog and low visibility present a natural hazard for aviation in the Hudson Bay region. Sixteen communities on the eastern and western shores of Hudson and James Bays, Canada, were selected for fog, ice fog, and low visibility statistical analyses for a range of 21 to 62 year time series. Both fog hours and ice fog hours were found to be in general decline, with some locations experiencing statistically significant declines. Spatial asymmetries for fog and ice fog were observed among the various areas within the Hudson Bay region. The more northerly locations in this study experienced statistically significant declines in fog hours while the southerly locations’ declines were not significant. Fog was significantly declining in some western Hudson Bay locations during spring and fall and in James Bay during winter and summer, but minimal trends were observed in eastern Hudson Bay. For ice fog hours, all of the locations in the western shore of Hudson Bay experienced a significant decline in winter while only one-third of the locations in eastern shores were found to be declining significantly during winter. Blowing snow, snow, ice and fog were the leading causes for reduced and low visibilities at the majority of the locations. Other factors such as rain contributed a minor role to low visibility.

Age Hardening in COR-Ten Steel

Weathering steels developed under the name COR-TEN steels, established themselves as a promising material to meet the demand for atmospheric corrosion resistance and eliminate the need for painting. COR-TEN steel is resistant to corrosive effect of weather such as rain, snow, ice, fog, etc. A coating of dark brown oxidation is developed over the metal surface, when it comes in contact with the environment thereby inhibiting the deeper penetration and negating the need for painting and reducing the rust-prevention cost over the years. Thus the steel is allowed to rust which forms a protective layer and slows down the rate of corrosion. The present study emphasizes the age hardening behavior of COR-TEN steel. The steel was subjected to solution treatment at 1000°C following accelerated cooling with water, oil and air. The oil quenched steel was then subjected to aging treatment at 400°C and 500°C for various times ranging from 5 min to 1500 min followed by water quenching. In order to ascertain the response to aging hardness measurement were conducted by employing a load of 20 Kgf. Metallographic examinations were also conducted to study the resulting structural transformations in various stages of investigations.

Sensitivity of Numerical Simulations of Near-Surface Atmospheric Conditions to Snow Depth and Surface Albedo during an Ice Fog Event over Heber Valley

This study examines the sensitivity of numerical simulations of near-surface atmospheric conditions to the initial surface albedo and snow depth during an observed ice fog event in the Heber Valley of northern Utah. Numerical simulation results from the mesoscale community Weather Research and Forecasting (WRF) Model are compared with observations from the Mountain Terrain Atmospheric Modeling and Observations (MATERHORN) Program fog field program. It is found that near-surface cooling during the nighttime is significantly underestimated by the WRF Model, resulting in the failure of the model to reproduce the observed fog episode. Meanwhile, the model also overestimates the temperature during the daytime. Nevertheless, these errors could be reduced by increasing the initial surface albedo and snow depth, which act to cool the near-surface atmosphere by increasing the reflection of downward shortwave radiation and decreasing the heating effects from the soil layer. Overall results indicate the important effects of snow representation on the simulation of near-surface atmospheric conditions and highlight the need for snow measurements in the cold season for improved model physics parameterizations.