Scheduling language and algorithm development study. Volume 2: Use of the basic language and module library

The capabilities of the specified scheduling language and the program module library are outlined. The summary is written with the potential user in mind and, therefore, provides maximum insight on how the capabilities will be helpful in writing scheduling programs. Simple examples and illustrations are provided to assist the potential user in applying the capabilities of his problem

Scheduling language and algorithm development study. Volume 3: Detailed functional specifications for the language and module library

The detailed functional specifications presented are written as requirements for software implementation of the language and the program modules, and are aimed at a specific audience

Nitrate uptake varies with tide height and nutrient availability in the intertidal seaweed Fucus vesiculosus

Intertidal seaweeds must cope with a suite of stressors imposed by aerial exposure at low tide, including nutrient limitation due to emersion. Seaweeds can access nutrients only when submerged, so individuals living higher compared to lower on the shore may have adaptations allowing them to acquire sufficient amounts of nutrients to survive and maintain growth. Using a combination of observations and experiments, we aimed to identify intraspecific variation in nitrate uptake rates across the intertidal distribution of F. vesiculosus, as well as test for acclimation in response to a change in tide height. We replicated our study at sites spanning nearly the entire Gulf of Maine coastline, to examine how local environmental variability may alter intraspecific variation in nitrate uptake. We found that average nitrate uptake rates were ~18% higher in upper compared to lower intertidal Fucus vesiculosus. Furthermore, we found evidence for both acclimation and adaptation to tide height during a transplant experiment. F. vesiculosus transplanted from the lower to the upper intertidal zone was characterized by increased nitrate uptake, but individuals transplanted from the upper to the lower intertidal zone retained high uptake rates. Our observations differed among Gulf of Maine regions and among time points of our study. Importantly, these differences may reflect associations between nitrate uptake rates and abiotic environmental conditions and seaweed nutrient status. Our study highlights the importance of long-term variation in ambient nutrient supply in driving intraspecific variation of seaweeds across the intertidal gradient and local and seasonal variation in ambient nutrient levels in mediating intraspecific differences

Strategies to improve reference databases for soil microbiomes

Microbial populations in the soil are critical in our lives. The soil microbiome helps to grow our food, nourishing and protecting plants, while also providing important ecological services such as erosion protection, water filtration and climate regulation. We are increasingly aware of the tremendous microbial diversity that has a role in soil heath; yet, despite significant efforts to isolate microbes from the soil, we have accessed only a small fraction of its biodiversity. Even with novel cell isolation techniques

Development of High Density Parts in the Low-Alloy, High-Performance Steel AF9628 Using Laser Powder Bed Fusion

A process parameter development study was performed in order to determine the printability of a low-alloy, high-performance steel, AF9628, using laser powder bed fusion. A weld track study was performed using 40 distinct laser power and speed combinations in order to determine which combinations produced acceptable conduction welds that would yield high-quality parts. Ten combinations with three distinct hatch spacing values were selected to create cylindrical specimens for porosity studies. Eight out of the ten combinations resulted in parts that were 99.5% dense. Two combinations that produced 99.9% dense parts were used to create tensile specimens. Tensile testing revealed that the ultimate tensile strength (UTS) for as-printed specimens manufactured using both of the processing conditions was significantly higher (24%) than the literature values for wrought AF9628. Heat-treating the specimens reduced their UTS values, but they still exceeded the literature value by 8%. Hardness measurements indicate that the Vickers hardness is approximately 10% lower for the as-printed specimens when compared to the literature value for wrought AF9628, while it is at least 6% greater for the heat-treated specimens than the wrought AF9628. Electron backscatter diffraction results showed that the as-printed microstructure exhibited features typical of the martensitic transformation in quench-and-temper steels