Open access to global forest data, especially ground-measured (in situ) records, is critical for saving the world’s forest systems. Integrated approaches to achieve sustainable data openness will ...involve legal assurances, shared ethics, innovative funding schemes and capacity development.
The use of composite structures in the automotive industry aims to produce vehicles able to meet both fuel economy and safety standards. This work focused on the improvement of static and impact ...strength of composite adhesive joints, avoiding early delamination of the composite. The techniques applied are mixed adhesive combinations (use of two adhesives in one overlap) and the use of crash resistant adhesives. Experimental results demonstrated that a crash resistant adhesive provides the best mechanical performance under quasi-static and impact loads. A mixed adhesive configuration provided good results and improvements over single adhesives.
The increasing use of composite structures in the automotive industry is due to strict regulations regarding both fuel efficiency and safety standards, since this kind of structures allow to produce ...strong yet light vehicles. The main advantage of the use of adhesives is the possibility of joining dissimilar materials, particularly composite materials, representing an optimal method in comparison with more traditional ones such as fastening or welding. This work focused on the development and validation of numerical models able to simulate the performance of previously experimentally tested joints. The experimental tests were performed to assess the improvement of quasi-static and impact strength of composite adhesive joints, and with the focus of avoiding early delamination of the composite substrates. The technique selected for this purpose was the use of mixed adhesive joints. Mixed adhesive joints combine two or more adhesives in a single lap joint and combine these properties to attain mechanical performance superior to that obtained using those adhesives individually. The numerical results demonstrated to be able to simulate the experimental results with reasonable accuracy.
Planted forests are critical to climate change mitigation and constitute a major supplier of timber/non-timber products and other ecosystem services. Globally, approximately 36% of planted forest ...area is located in East Asia. However, reliable records of the geographic distribution and tree species composition of these planted forests remain very limited. Here, based on extensive in situ and remote sensing data, as well as an ensemble modeling approach, we present the first spatial database of planted forests for East Asia, which consists of maps of the geographic distribution of planted forests and associated dominant tree genera. Of the predicted planted forest areas in East Asia (948,863 km
), China contributed 87%, most of which is located in the lowland tropical/subtropical regions, and Sichuan Basin. With 95% accuracy and an F1 score of 0.77, our spatially-continuous maps of planted forests enable accurate quantification of the role of planted forests in climate change mitigation. Our findings inform effective decision-making in forest conservation, management, and global restoration projects.
The research presents the inter-comparison of atmospheric variables measured by 9 automatic weather stations. This set of data was compared with the measurements of other weather stations in order to ...standardize the values that must be adjusted when taken to different areas. The data of a set of a total of 9 GMX500, which measures conventional meteorological variables, and 10 WS100 sensors, which measures precipitation parameters. The automatic stations were set up at the Huancayo Observatory (Geophysical Institute of Peru) for a period of 5 months. The data set of GMX500 were evaluated comparing with the average of the 9 sensors and the WS100 was compared with an optical disdrometer Parsivel2. The temperature, pressure, relative humidity, wind speed, rainfall rate, and drop size distribution were evaluated. A pair of GMX500 sensors presented high data dispersion; it was found found that the errors came from a bad configuration; once this problem was solved, good agreement was archived, with low RMSE and high correlation. It was found that the WS100 sensors overestimate the precipitation with a percentage bias close to 100% and the differences increase with the greater intensity of rain. The drop size distribution retrieved by WS100 have unrealistic behavior with higher concentrations in diameters of 1 mm and 5 mm, in addition to a flattened curve.
Larval source management is a promising component of integrated malaria control and elimination. This requires development of a framework to target productive locations through process-based ...understanding of habitat hydrology and geomorphology.
We conducted the first catchment scale study of fine resolution spatial and temporal variation in Anopheles habitat and productivity in relation to rainfall, hydrology and geomorphology for a high malaria transmission area of Tanzania.
Monthly aggregates of rainfall, river stage and water table were not significantly related to the abundance of vector larvae. However, these metrics showed strong explanatory power to predict mosquito larval abundances after stratification by water body type, with a clear seasonal trend for each, defined on the basis of its geomorphological setting and origin.
Hydrological and geomorphological processes governing the availability and productivity of Anopheles breeding habitat need to be understood at the local scale for which larval source management is implemented in order to effectively target larval source interventions. Mapping and monitoring these processes is a well-established practice providing a tractable way forward for developing important malaria management tools.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This article reports on sub-10-nm quaternary barrier InAlGaN/GaN high electron mobility transistors (HEMTs) grown by metal-organic-vapor-phase-epitaxy (MOVPE) with an in situ SiN passivation layer ...and an ultrashort gate length of 200 nm. Two batches of HEMTs with two SiN thicknesses (t SiN ) of 14 and 22 nm are studied. Low-frequency noise (LFN) measurements of the drain current have been carried out in the linear regime and showed that the in situ SiN thickness has no impact on the noise performance. S ID /I D 2 in the linear regime dependence over the gate overdrive shows that the channel noise is located under the gate and that the noise is not impacted by the thickness of the in situ SiN layer.
The formation of recess etched Au-free ohmic contacts to an InAlN AlN GaN heterostructure is investigated. A Ta Al Ta metal stack is used to produce contacts with contact resistance (Rc) as low as ...0.14 mm. It is found that Rc decreases with increasing recess depth until the InAlN barrier is completely removed. For even deeper recesses Rc remains low but requires annealing at higher temperatures for contact formation. The lowest Rc is found for contacts where the recess etch has stopped just above the 2D electron gas channel. At this depth the contacts are also found to be less sensitive to other process parameters, such as anneal duration and temperature. An optimum bottom Ta layer thickness of 5-10 nm is found. Two reliability experiments preliminary confirm the stability of the recessed contacts.
Many adaptation strategies focus on improving short-term capacities to cope with environmental change, but ignore the possibility that they might inadvertently increase vulnerability to unforeseen ...changes in the future. To help develop more effective long-term strategies, we present a conceptual framework of adaptation. The framework emphasizes that in order to ensure that existing problems are not exacerbated, adaptation must: (1) address both human-induced and biophysical drivers of undesired ecological change; (2) maintain a diversity of future response options; and (3) nurture the kinds of human capacities that enable the uptake of those response options. These requirements are often not met when adaptation strategies rely on technological fixes, which tend to concentrate on coping with the biophysical symptoms of problems rather than addressing human behavioral causes. Furthermore, to develop effective, long-term adaptation, greater emphasis is needed on strategies that enhance, rather than erode, the human values, skills, and behaviors conducive to sustainable activities. Participatory approaches to environmental stewardship are part of the solution to this problem.
PDF
