Reactivity of Hydroxymethylated Resorcinol Coupling Agent as it Affects Durability of Epoxy Bonds to Douglas-fir

Epoxy adhesives develop strong bonds to wood, but they lack the structural durability to withstand the severe stresses from repeated water soaking and drying. Research at the Forest Products Laboratory led to a discovery that hydroxymethylated resorcinol (HMR) physicochemically couples to both epoxy adhesive and lignocellulosics of wood to produce bonds that are extraordinarily resistant to dclamination. The HMR coupling agent is quite reactive at room temperatures; therefore, the length of its reaction time, or the time between preparing the solution and applying it to the wood surface, strongly influences the durability of adhesion. The experiments in this study defined the optimum range of reaction time when adhesion is maximum for epoxy bonds to HMR-primed Douglas-fir. Heats of reaction (by differential scanning calorimetry), molecular-size distribution (by gel permeation chro-matography), and chemical structures of HMR (by carbon-13 nuclear magnetic resonance spectros-copy) are described for this range of optimum reaction times

Frost quakes in wetlands in northern Finland during extreme winter weather conditions and related hazard to urban infrastructure

The paper reports the first results of an experiment in northern Finland during winter 2022–2023 that aimed at studying seismic events caused by seasonal freezing in the so-called critical zone (CZ) of the Earth. These events have attracted public attention recently, as multiple reports about them from local inhabitants in Arctic and sub-Arctic areas appeared on social networks. To make an instrumental study of such events, to reveal the relationship between their occurrence and winter weather conditions, and to evaluate the possible hazard, we installed two high-resolution seismic arrays with co-located soil temperature stations at two sites in Finland, one of them being in the city of Oulu in the sub-Arctic area (65.04° N, 25.61° E) and the other one above the polar circle in the municipality of Sodankylä (67.36° N, 26.63° E). The equipment recorded continuous seismic and soil temperature data during November 2022–April 2023. Based on reports from the inhabitants of Talvikangas (Oulu) about the ground shaking and unusual noises on 6 January 2023 and their observations of new fractures on the roads there, we selected the time interval for the identification of frost quakes that originated during that day from continuous seismic records in Talvikangas and in Sodankylä. During the selected time interval, the extremely rapid air temperature drops of about −1.4 °C h−1 in Talvikangas and −0.88 °C h−1 in Sodankylä were observed. We identified and located two types of seismic events – namely, frost quakes with frequencies of about 10–20 Hz, with waveforms like those of tectonic events, and irregularly shaped frost tremors with frequencies of about 120–180 Hz. The sources of frost quakes in Talvikangas are mainly located on irrigated wetland, while in Sodankylä, about 50 % of registered frost quakes were caused by ice fracturing on the Kitinen River. However, several relatively strong events, with their origin in the wetlands, were also recorded. A significant number of sources of frost tremors are confined to wetland areas cut by irrigation channels and to roads cleaned from snow during winter both in Talvikangas and in Sodankylä. We calculated ground accelerations and ground velocities for the strongest events from both groups and compared them to equivalent properties of other seismic signals, like distant local earthquakes in the area, mining production blasts, and cargo train vibration. Our study shows that high-frequency frost tremors corresponding to surface fracture opening in the uppermost frozen surface layer of a thickness of up to 5 cm can directly damage infrastructure objects like roads and basements of buildings. Surface waves, produced by frost quakes and propagating inside the shallow soil layer, have large enough ground accelerations at epicentral distances of hundreds of metres. Therefore, frost quakes should be considered a phenomenon that can potentially damage infrastructures, and they have to be taken into account in seismic hazard assessments. Our research is the first instrumental study of seismic events originating from wetland areas. These events occur as a result of the interaction between the uppermost layer of the solid Earth's CZ and atmosphere processes that deserves further study.</p

Climate variability, oceanography, bowhead whale distribution, and Iñupiat subsistence whaling near Barrow, Alaska

Author Posting. © Arctic Institute of North America, 2010. This article is posted here by permission of Arctic Institute of North America for personal use, not for redistribution. The definitive version was published in Arctic 63 (2010): 179-194.The annual migration of bowhead whales (Balaena mysticetus) past Barrow, Alaska, has provided subsistence hunting to Iñupiat for centuries. Bowheads recurrently feed on aggregations of zooplankton prey near Barrow in autumn. The mechanisms that form these aggregations, and the associations between whales and oceanography, were investigated using field sampling, retrospective analysis, and traditional knowledge interviews. Oceanographic and aerial surveys were conducted near Barrow during August and September in 2005 and 2006. Multiple water masses were observed, and close coupling between water mass type and biological characteristics was noted. Short-term variability in hydrography was associated with changes in wind speed and direction that profoundly affected plankton taxonomic composition. Aggregations of ca. 50–100 bowhead whales were observed in early September of both years at locations consistent with traditional knowledge. Retrospective analyses of records for 1984–2004 also showed that annual aggregations of whales near Barrow were associated with wind speed and direction. Euphausiids and copepods appear to be upwelled onto the Beaufort Sea shelf during Eor SEwinds. A favorable feeding environment is produced when these plankton are retained and concentrated on the shelf by the prevailing westward Beaufort Sea shelf currents that converge with the Alaska Coastal Current flowing to the northeast along the eastern edge of Barrow Canyon.This work was supported by NSF Grants OPPPP-0436131 to C. Ashjian (S. Braund Subcontract), OPPPP-0436110 to R. Campbell, OPPPP-0436127 to W. Maslowski, OPPPP-0436009 to C. Nicolson and J. Kruse, OPPPP-043166 to S. Okkonen, and OPPPP-0435956 to Y. Spitz, E. Sherr, and B. Sherr

Effect of Rainfall and Elevation on Specific Gravity of Coast Douglas-Fir

Analysis is made of the effects of five ranges of summer precipitation and three ranges of elevation on variation in specific gravity of Coast Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco). The average specific gravity of Coast Douglas fir wood formed during single growing seasons varied from 0.52 for dry summers to 0.45 for wet summers. The negative linear trend held for three elevational levels. Wood produced under a combination of dry summers at low elevations averaged 0.55 specific gravity, whereas wood produced during wet summers at high elevations averaged only 0.44 specific gravity. Both percentage of latewood and thickness of latewood tracheid wall followed trends that were similar to those of specific gravity with summer rainfall and elevation

Gender differences in mortality and quality of life after septic shock : A post-hoc analysis of the ARISE study

Purpose: To assess the impact of gender and pre-menopausal state on short- and long-term outcomes in patients with septic shock. Material and methods: Cohort study of the Australasian Resuscitation in Sepsis Evaluation (ARISE) trial, an international randomized controlled trial comparing early goal-directed therapy (EGDT) to usual care in patients with early septic shock, conducted between October 2008 and April 2014. The primary exposure in this analysis was legal gender and the secondary exposure was pre-menopausal state defined by chronological age ( Results: 641 (40.3%) of all 1591 ARISE trial participants in the intention-to-treat population were females and overall, 337 (21.2%) (146 females) patients were 50 years of age or younger. After risk-adjustment, we could not identify any survival benefit for female patients at day 90 in the younger (50 years) age-group (aOR: 1.10 (0.81-1.49), p = .56). Similarly, there was no gender-difference in ICU, hospital, 1-year mortality nor quality of life measures. Conclusions: This post-hoc analysis of a large multi-center trial in early septic shock has shown no short- or long-term survival effect for women overall as well as in the pre-menopausal age-group. (C) 2019 Elsevier Inc. All rights reserved.Peer reviewe

Public and open Internet of Things for smart cities:the SME perspective

Abstract Internet of Things technologies and platforms can provide both novel applications and business strategies for the companies of different technological application areas. However, risks for intensive participation in utilizing novel and expensive technologies into their business and products, might be considered risky by small and medium-sized enterprises (SMEs). Thus, the role of the open source platforms and possibility to test them in the small-scale pilot studies, becomes crucial. In this work, we discuss four different SMEs participating in the open and research-driven IoT pilots in the context of the smart cities. We demonstrate the value of the open Internet of Things platforms can provide for small and medium-sized enterprises working in the area of smart cities, as well as challenges we met

Frost quakes:crack formation by thermal stress

Abstract Fractures in frozen soils (frost quakes) can cause damage to buildings and other infrastructure, but their formation mechanisms remain poorly understood. A methodology was developed to assess thermal stress on soil due to changes in climate and weather conditions and to investigate the connection between thermal stress and frost quakes in central Finland due to brittle fracturing in uppermost soils. A hydrological model was used to simulate snow accumulation and melt, and a soil temperature model was used to simulate soil temperature at different depths beneath the snow pack. The results of modeling, together with measurements of air temperature, snow cover thickness, and soil temperature, were used to calculate temporal variations in thermal stress in soil. We show that frost quakes occur when thermal stress caused by a rapid decrease in temperature exceeds fracture toughness and strength of the soil‐ice mixture. We compared calculated thermal stress on soil, critical stress intensity factor, and a seismogram recorded in a suburban region in central Finland. Our results suggest that this methodology can be used to predict thermal stresses on soil and identify stress values that may lead to fractures of frozen soils, that is, frost quakes

Students and Teachers’ Need for Sustainable Education: Lessons from the Pandemic

The COVID-19 pandemic challenged the sustainability of higher education as millions of students were forced out of school, shifting to online learning instead of in-class education. In the Erasmus+ project, Virtual Presence in Higher Education Hybrid Learning Delivery (VIE), we were concerned with the level of readiness and the ability of higher-education students and teachers to face this changing situation. This paper reports the results of a survey which assessed the experiences that students and teachers had during the pandemic and, in particular, the development of soft skills through active learning methodologies. The project results show that there are still some unmet needs, but existing digital technologies, tools, and platforms already provide valuable solutions both for students and teachers that ensure a continuation of high-quality learning experiences. © 2022 by the authors