Populus tremuloides seedling establishment: An underexplored vector for forest type conversion after multiple disturbances

Ecosystem resilience to climate change is contingent on post-disturbance plant regeneration. Sparse gymnosperm regeneration has been documented in subalpine forests following recent wildfires and compounded disturbances, both of which are increasing. In the US Intermountain West, this may cause a shift to non-forest in some areas, but other forests may demonstrate adaptive resilience through increased quaking aspen (Populus tremuloides Michx.) dominance. However, this potential depends on ill-defined constraints of aspen sexual regeneration under current climate. We created an ensemble of species distribution models for aspen seedling distribution following severe wildfire to define constraints on establishment. We recorded P. tremuloides seedling locations across a post-fire, post-blowdown landscape. We used 3 algorithms (Mahalanobis Typicalities,Multilayer Perceptron Artificial Neural Network, and MaxEnt) to create spatial distribution models for aspen seedlings and to define constraints. Each model performed with high accuracy and was incorporated into an ensemble model, which performed with the highest overall accuracy of all the models. Populus tremuloides seedling distribution is constrained primarily by proximity to unburned aspen forest and annual temperature ranges, and secondarily by light availability, summer precipitation, and fire severity. Based on model predictions and validation data, P. tremuloides seedling regeneration is viable throughout 54% of the post-fire landscape, 97% of which was previously conifer-dominated. Aspen are less susceptible to many climatically-sensitive disturbances (e.g. fire, beetle outbreak, wind disturbance), thus, aspen expansion represents an important adaptation to climate change. Continued aspen expansion into post-disturbance landscapes through sexual reproduction at the level suggested by these results would represent an important adaptation to climate change and would confer adaptive forest resilience by maintaining forest cover, but would also alter future disturbance regimes, biodiversity, and ecosystem services.Ye

Functionalization Of Graphene And Reduced Graphene Oxide In Different Matrices

Graphene (G) presents a huge variety of intriguing properties, as extraordinary electronic transport characteristics. G, thanks to its low chemical reactivity, can also be used as an active support for catalytic nanoparticles. Some possible graphene application could be: its employment in active material in electronic devices such as sensors [1], batteries [2], supercapacitors, hydrogen storage systems or as fillers to produce multifunctional nanocomposite polymeric materials [3]. In more detail we would like to examine: different approach of reduction and functionalization of in situ reduced graphene oxide obtaining an enhancement of thermal conductivity and an resistivity decrease [4]. Surface modification and functionalization of rGO to improve its dispersion in organic solvent and also polymeric matrix [5]

Evaluating Wildlife Vulnerability to Mercury Pollution From Artisinal and Small-Scale Gold Mining in Madre de Dios, Peru

“Illegal, artisanal and small-scale gold mining (ASGM) often occurs in remote highly biodiverse areas, such as the Madre de Dios region of Peru. Mercury used in gold mining bioaccumulates in the environment and poses developmental, hormonal, and neurological threats to wildlife. The impact of ASGM on biodiversity remains largely unknown. We used geographic information science to create a spatial model of pollution risk from mining sites, in order to predict locations and species assemblages at risk. Multicriteria evaluation was used to determine how flow accumulation, distance from mining areas, total suspended sediment load, and soil porosity influenced the vulnerability of regions to mercury pollution. Results suggest that there is considerable opportunity for protection of areas with high biodiversity and vulnerability north of the Madre de Dios River where much of the land is not protected. Our study highlights the need for future ASGM research to consider more than deforestation risk alone while protecting the areas’ unmatched biodiversity.

SimSat Educational Program Development

The Simulated Satellite (SimSat) Project is a NASA educational outreach program. The main goal of this project was to design, build, test, document, and fly a SimSat payload for high school students to replicate. We defined design requirements and divided the project into subsystems. Each subsystem was then developed and tested independently, followed by integration and testing of the entire system prototype. Once the prototype was finished we conducted two successful test flights at NASA Wallops Flight Facility. Finally we analyzed the results and concluded that our design met all of the system requirements

Mechanical behavior of macadamia nutshells

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Radical photoinduced cationic frontal polymerization in porous media

Two different interpenetrating phase composites were produced using a radical photoinduced cationic frontal polymerization process. The composites were based on polyurethane (PU) and aluminium open-cell foams impregnated with a formulation of a cycloaliphatic epoxy with different concentrations of a cationic photoinitiator and a thermal initiator. The influence of both types of initiators on the frontal polymerization features was systematically evaluated for the PU foam. It was found to occur only when the concentration of both initiators was greater than 0.5 wt%, leading to full conversion of the epoxy in the whole volume of the 15 mm thick composite samples within less than 100 s. The maximum temperature reached by the propagation front was in the range 275–305 °C depending on the type of formulation, leading to pores in the epoxy phase and extensive degradation of the PU phase. In the case of the opaque aluminium foam, an additional layer of pure resin was required on the UV-exposed surface, which corresponded to a critical mass of a few grams to ensure sufficient heat generation and trigger the front propagation. © 2020 Society of Chemical Industry