Icy weather in Texas raises power grid questions

Headline UNITED STATES: Weather puts utilities under scrutiny

The dynamics of Covid-19: weather, demographics and infection timeline

We study the effects of temperature, absolute humidity, population density and when country/U.S. state reached 100 cases on early pace of Covid-19 expansion, for all 50 U.S. states and 110 countries with enough data. For U.S. states, weather variables show opposite effects when compared to the case of countries: higher temperature or absolute humidity imply faster early outbreak. The higher the population density or the earlier the date when state reached 100th case, the faster the pace of outbreak. When all variables are considered, only population density and the timeline variable show statistical significance. Discounting the effect of the timeline variable, we obtain an estimate for the initial growth rate of Covid-19, which can be also used to estimate the basic reproduction number for a region, in terms of population density. This has policy implications regarding how to control the pace of Covid-10 outbreak in a particular area, and we discuss some of them. In the case of countries, for which we did not have demographic information, weather variables lose statistical significance once the timeline variable is added. Relaxing CI requirements, absolute humidity contributes mildly to the reduction of growth rate of cases for the countries studied. Our results suggest that population density should be employed as a control variable and that analysis should have a local character, for subregions and countries separately, in studies involving the dynamics of Covid-19 and similar infectious diseases.

Characterizing the Natural Temperature and Humidity Environment Severity

Severe yet common product environmental tests are 1000 hours at 85 °C/85% RH or 95 °C/95% RH for products, circuit card assemblies, and electronic components. Such environments never occur naturally; however, they attempt to simulate the corrosion damage that could be expected in service. To what natural environment do these tests correlate? Further, how do tests based on MIL-HDBK-310, MIL-STD-810, and STANAG 2895 B3 daily environments compare to these standard test environments? The analysis employs the Physics-of-Failure (POF) Peck power law temperature-humidity model with common conservative values for the Arrhenius activation energy and the relative humidity exponent, based on aluminum corrosion, coupled with climatological data from 49 United States weather stations and 19 international locations. The monthly average temperature and humidity extremes were transformed into an hourly diurnal cycle assumed to occur every day of each month. Using the power law model the equivalent time at the test condition was calculated for each day, and summed for each month and location. The 85 °C/85% RH test can be correlated with about 10 years in a hot and moist natural environment, such as Singapore, with 1000 hours of 95 °C/95% RH exposure equivalent to 25 years. Long-term tests based on the worst-case diurnal temperature and humidity cycles in military standards are on the order of 1 in 1,000,000 probability of occurrence in nature.

Regular Voters, Marginal Voters and the Electoral Effects of Turnout

How do marginal voters differ from regular voters? This article develops a method for comparing the partisan preferences of regular voters to those marginal voters whose turnout decisions are influenced by exogenous factors and applies it to two sources of variation in turnout in the United States—weather and election timing. In both cases, marginal voters are over 20 percentage points more supportive of the Democratic Party than regular voters—a significant divide. The findings suggest that the expansion or contraction of the electorate can have important consequences. Moreover, the findings suggest that election results do not always reflect the preferences of the citizenry, because the marginal citizens who may stay home have systematically different preferences than those who participate. Finally, the methods developed in the article may enable future researchers to compare regular and marginal voters on many different dimensions and in many different electoral settings.