Physical characteristics of AFEX-pretreated and densified switchgrass,prairie cord grass,and corn stover

The goal of the study was to evaluate and compare the physical properties of control, pretreated and densified corn stover, switchgrass, and prairie cord grass samples. Ammonia Fiber Expansion (AFEX) pretreated switchgrass, corn stover, and prairie cord grass samples were densified by using the comPAKco device developed by Federal Machine Company of Fargo, ND. The densified biomass were referred as “PAKs” in this study. All feedstocks were ground into three different grind size of 2, 4 and 8 mm prior to AFEX pretreatment and the impact of grinding on pellet properties was studied. The results showed that the physical properties of AFEX-PAKed material were not influenced by the initial grind size of the feedstocks. The bulk density of the AFEX-PAKed biomass increased by 1.2–6 fold as compared to untreated and AFEX-pretreated materials. The durability of the AFEX-PAKed materials were between 78.25 and 95.2%, indicating that the AFEX-PAKed biomass can be transported easily. To understand the effect of storage on the physical properties of these materials, samples were stored in the ambient condition (20 ± 2 °C and 70 ± 5% relative humidity) for six months. After storage, thermal properties of the biomass did not change but glass transition temperature decreased. The water absorption index and water solubility index of AFEX-treated and AFEX-PAKed biomass showed mixed trends after storage. Moisture content decreased and durability increased upon storage.     

Model checking temporal knowledge and commitments in multi-agent systems using reduction

Though modeling and verifying Multi-Agent Systems (MASs) have long been under study, there are still challenges when many different aspects need to be considered simultaneously. In fact, various frameworks have been carried out for modeling and verifying MASs with respect to knowledge and social commitments independently. However, considering them under the same framework still needs further investigation, particularly from the verification perspective. In this article, we present a new technique for model checking the logic of knowledge and commitments (CTLKC⁺). The proposed technique is fully-automatic and reduction-based in which we transform the problem of model checking CTLKC⁺ into the problem of model checking an existing logic of action called ARCTL. Concretely, we construct a set of transformation rules to formally reduce the CTLKC⁺ model into an ARCTL model and CTLKC⁺ formulae into ARCTL formulae to get benefit from the extended version of NuSMV symbolic model checker of ARCTL. Compared to a recent approach that reduces the problem of model checking CTLKC⁺ to another logic of action called GCTL¹, our technique has better scalability and efficiency. We also analyze the complexity of the proposed model checking technique. The results of this analysis reveal that the complexity of our reduction-based procedure is PSPACE-complete for local concurrent programs with respect to the size of these programs and the length of the formula being checked. From the time perspective, we prove that the complexity of the proposed approach is P-complete with regard to the size of the model and length of the formula, which makes it efficient. Finally, we implement our model checking approach on top of extended NuSMV and report verification results for the verification of the NetBill protocol, taken from business domain, against some desirable properties. The obtained results show the effectiveness of our model checking approach when the system scales up.     

Nitrogen contributions of alley cropped Trifolium pratense may sustain short rotation woody crop yields on marginal lands

Nutrient Cycling in Agroecosystems - Incorporating nitrogen-fixing cover crops into short rotation woody crop (SWRC) plantations may increase soil and tree nitrogen while sustaining, or even...     

Ontogenetic habitat use and seasonal activity of Nile crocodiles (Crocodylus niloticus) in the Lake Albert delta,East Africa

Crocodiles play important roles in many ecosystems, but their populations worldwide are threatened by human exploitation and habitat destruction. We studied ontogenetic changes in habitat use and seasonal activity patterns in a population of Nile crocodiles (Crocodylus niloticus) inhabiting the Lake Albert Delta Wetland System, a Ramsar Site of international importance in Murchison Falls National Park of western Uganda. A total of 186 crocodile observations were made from monthly surveys of five transects during October 2017 to September 2018. Crocodiles exhibited a marginally bi-modal seasonal pattern, with the fewest observations from July to August and October to November, and the highest observations from January to February and April to May. Crocodiles were most frequently encountered along the north shore of the delta, especially on riverbanks with woody vegetation, followed by Cyperus papyrus-Vossia dominated habitats, while crocodiles were infrequently observed on islands and muddy banks. Habitat niche breadth was narrowest in hatchlings and widest in sub-adults, with juveniles and large adults exhibiting intermediate values. Overlap in habitat resource use across size classes was generally high, with the lowest overlap between hatchlings and juveniles, and the highest between large and sub-adult crocodiles. Our study on Nile crocodiles in the Lake Albert delta provides insights into habitat partitioning among different demographic segments of this population that can be utilized to improve its management in one of Africa’s Great Lakes by spatially and temporally focusing conservation efforts on the most used habitats and seasonal aggregations, respectively.     

Movement of Sea Lamprey in the Lake Champlain Basin

Sea lamprey (Petromyzon marinus) are a nuisance aquatic species in the Great Lakes and Lake Champlain that have devastated native fish populations and hampered the restoration of sport fisheries. This study examined inter-basin movement of sea lamprey in Lake Champlain to identify tributaries that contribute parasitic-phase sea lamprey and provide information for prioritizing those tributaries for sea lamprey control. A total of 4,125 recently metamorphosed sea lamprey was captured in tributaries to Lake Champlain and marked using coded wire tags between the fall of 2001 and winter 2003. These sea lamprey migrated to the lake to prey on salmonids and other fishes and returned to tributaries to spawn about 12–18 months after migration. We recaptured 6 tagged sea lamprey from the lake from spring 2002 through winter 2004, and 35 from tributaries in spring 2003 and 2004. We noted no apparent trends in movement among basins. Sea lamprey were collected at distances up to 64 km from their natal tributaries. Tributary contributions of parasites were significantly different from expectations in the 2002 parasitic-phase cohort (χ² = 9.668, p < 0.011, 3 df), suggesting differential survival rates among out-migrating transformers from different tributaries. Estimates of the lake-wide out-migrating transformer population for the 2002 and 2003 parasitic-phase cohorts were 269,139 ± 55,610 (SD) and 111,807 ± 23,511 (SD). Results from this study suggest that sea lamprey movement is not inhibited by causeways dividing sub-basins, but movement among sub-basins is somewhat constrained. This indicates that management efforts to control sea lamprey should continue to treat the lake as a single system.     

Effect of anisotropy of tin on thermomechanical behavior of solder joints

Properties of body centered tetragonal tin are highly anisotropic. As a consequence large stresses can develop at the tin grain boundaries due to coefficient of thermal expansion mismatch during temperature excursions. A modeling approach to evaluate the 3D stress states that develop at grain boundaries during thermomechanical fatigue in tin-based solder is presented. Development of significant amounts of stresses in the plane of the grain boundary can cause grain-boundary sliding and surface-relief effects, while those normal to the grain boundary can cause grain-boundary decohesion and cracking.     

An Investigation into Glucose as a Potential Precursor of N-Nitrosothiazolidine in Bacon

The possible involvement of glucose in the formation of N-nitrosothiazolidine (NTHZ) in bacon was investigated by pumping pork bellies with brines containing added glucose (2 and 4%). Raw bacon samples processed with glucose had significantly lower levels of N-nitrosothiazolidine-4-carboxylic acid than the smoked control bacons. When the bacon samples with glucose were fried for 6 and 12 min, no NTHZ was detected in the fried products. N-Nitrosopyrrolidine (NPYR) levels in these samples were much lower than those in the fried control samples. Results of this study demonstrate that the contribution of glucose to NTHZ formation in bacon is minimal relative to that of formaldehyde in the wood smoke.     

A non-specific lipid transfer protein from Arabidopsis is a cell wall protein

Lipid transfer proteins (LTPs), mediate the transfer of phospholipids between membranes in vitro. However, the in vivo function of LTPs is not known. To determine the precise location of a non-specific LTP from Arabidopsis, a cDNA clone was used to produce an Arabidopsis LTP:protein A fusion. Antibodies raised against the fusion were used to localize the Arabidopsis LTP by immunoelectron microscopy. LTP was found to be located in the cell wall, mainly in epidermal cells. This location appears to be inconsistent with the proposed role of the protein in intracellular lipid transfer.