4,095 research outputs found
Mechanical Properties of Corn and Soybean Meal
Ground corn and soybean meal are common ingredients in feed mixes. The knowledge of their mechanical properties is important to the feed manufacturer and consumer. Changes in these properties can lead to abnormally high or low levels of active ingredients in finished feed, thus decreasing its quality. Mechanical properties of wheat, corn meal, and soybean meal were investigated using a modified direct shear apparatus. The moisture content (wet basis), uncompacted bulk density, and particle density were: 10.4%, 733 kg/m3, and 1410 kg/m3 for soft red winter wheat; 11.4%, 583 kg/m3, and 1350 kg/m3 for soybean meal; and 11.7%, 595 kg/m3, and 1410 kg/m3 for corn meal, respectively. A relatively long sliding path of 60 mm was utilized in shear testing to account for the high compressibility of the materials and minimize boundary effects. The compressibility of the materials was determined at a maximum vertical pressure of 34.4 kPa, which caused a density increase of 21% for corn meal while the density of wheat and soybean meal increased by approximately 5%. Frictional properties were tested for seven levels of vertical consolidation pressures ranging from 4.1 to 20.7 kPa. The high compressibility of corn meal resulted in severe stick–slip behavior of the frictional force–displacement relationships. The angles of internal friction of wheat, soybean meal, and corn meal were found to be 26.3° ±0.3°, 33.9° ±0.9°, and 30.7° ±1.4°, respectively. Cohesion of soybean meal and corn meal was approximately 0.7 kPa without a clear relation to consolidation stress and approximately 0.3 kPa for wheat. With cohesion values lower than 4 kPa, all three materials should be treated as free–flowing in terms of Eurocode 1. Corn and soybean meals are known to cause flow problems in practice that were not confirmed during testing. In practical storage conditions, materials undergo a longer consolidation period. Our tests have shown that with processes that have a short duration and low consolidation pressures, these materials should be treated as free–flowing
Observations of Site Amplification and Liquefaction in the Jun 23, 2001, Southern Peru Earthquake
The Mw 8.4 Southern Peru Earthquake of June 23, 2001 caused extensive damage in a widespread area in southern Peru and northern Chile, including several important population centers. Damage in some of these cities was correlated with local soil conditions and topography, suggesting the influence of local site amplification effects in damage distributions. The earthquake caused numerous instances of other types of geotechnical related ground failures, including liquefaction and lateral spreads in river valleys, seismic compression of highway fills, and slope failures. This work focuses on case histories documenting site amplification and liquefaction in the Southern Peru earthquake. Among the liquefaction events observed in this earthquake, the liquefaction of a heap-leach pad is the first reported failure of its type in a seismic event
The thermodynamic brain.
Apart from its complex functionality, the brain is a robust thermodynamic machine; the tissue metabolic rate is high and it is thermally shielded by a skull. Therefore, if there is no high-volume blood flow to cool and stabilize the brain temperature, the possibility of unstable behavior seems to be high. Inflowing arterial blood is normally cooler than the brain tissue temperature, and outflowing venous blood is normally warmer than arterial blood but cooler than the brain tissue. Brain blood flow can thus be understood as a cooler for the brain. Pros and cons of clinical measurement, with clear indication for a multimodal monitoring approach, are discussed along with a brief review of basic facts known about temperature, cerebral blood flow and volume, intracranial pressure, and compartmental compliances of the brain.This is the final version of the article. It first appeared from BioMed Central via http://dx.doi.org/10.1186/s13054-014-0693-
ToyArchitecture: Unsupervised Learning of Interpretable Models of the World
Research in Artificial Intelligence (AI) has focused mostly on two extremes:
either on small improvements in narrow AI domains, or on universal theoretical
frameworks which are usually uncomputable, incompatible with theories of
biological intelligence, or lack practical implementations. The goal of this
work is to combine the main advantages of the two: to follow a big picture
view, while providing a particular theory and its implementation. In contrast
with purely theoretical approaches, the resulting architecture should be usable
in realistic settings, but also form the core of a framework containing all the
basic mechanisms, into which it should be easier to integrate additional
required functionality.
In this paper, we present a novel, purposely simple, and interpretable
hierarchical architecture which combines multiple different mechanisms into one
system: unsupervised learning of a model of the world, learning the influence
of one's own actions on the world, model-based reinforcement learning,
hierarchical planning and plan execution, and symbolic/sub-symbolic integration
in general. The learned model is stored in the form of hierarchical
representations with the following properties: 1) they are increasingly more
abstract, but can retain details when needed, and 2) they are easy to
manipulate in their local and symbolic-like form, thus also allowing one to
observe the learning process at each level of abstraction. On all levels of the
system, the representation of the data can be interpreted in both a symbolic
and a sub-symbolic manner. This enables the architecture to learn efficiently
using sub-symbolic methods and to employ symbolic inference.Comment: Revision: changed the pdftitl
Characterisation of Methane Plasma Treated Carbon Surfaces
Los Alamitos, US
Glacier algae:a dark past and a darker future
“Glacier algae” grow on melting glacier and ice sheet surfaces across the cryosphere, causing the ice to absorb more solar energy and consequently melt faster, while also turning over carbon and nutrients. This makes glacier algal assemblages, which are typically dominated by just three main species, a potentially important yet under-researched component of the global biosphere, carbon, and water cycles. This review synthesizes current knowledge on glacier algae phylogenetics, physiology, and ecology. We discuss their significance for the evolution of early land plants and highlight their impacts on the physical and chemical supraglacial environment including their role as drivers of positive feedbacks to climate warming, thereby demonstrating their influence on Earth’s past and future. Four complementary research priorities are identified, which will facilitate broad advances in glacier algae research, including establishment of reliable culture collections, sequencing of glacier algae genomes, development of diagnostic biosignatures for remote sensing, and improved predictive modeling of glacier algae biological-albedo effects
Adsorption of Carbon Dioxide, Ammonia, Formaldehyde, and Water Vapor on Regenerable Carbon Sorbents
Results are presented on the development of reversible sorbents for the combined carbon dioxide, moisture, and tracecontaminant (TC) removal for use in Extravehicular Activities (EVAs), and more specifically in the Primary Life Support System (PLSS). The currently available life support systems use separate units for carbon dioxide, trace contaminants, and moisture control, and the longterm objective is to replace the above three modules with a single one. Furthermore, the current TCcontrol technology involves the use of a packed bed of acidimpregnated granular charcoal, which is nonregenerable, and the carbonbased sorbent under development in this project can be regenerated by exposure to vacuum at room temperature. In this study, several carbon sorbents were fabricated and tested for simultaneous carbon dioxide, ammonia, formaldehyde, and water sorption. Multiple adsorption/vacuumregeneration cycles were demonstrated at room temperature, and also the enhancement of formaldehyde sorption by the presence of ammonia in the gas mixture
Attenuated and Nonproductive Viral Transcription in the Lymphatic Tissue of HIV-1-Infected Patients Receiving Potent Antiretroviral Therapy
Human immunodeficiency virus type 1 (HIV-1) RNA that persists in the lymphoid tissue of patients despite treatment with highly active antiretroviral therapy (HAART) may represent extracellular virions or intracellular RNAs residing within HIV-infected cells. To further characterize residual viral transcription, tonsil biopsy specimens from patients receiving long-term HAART, untreated patients, and patients undergoing 2 weeks of structured treatment interruption were analyzed by polymerase chain reaction quantification of virion-encapsidated RNA, intracellular unspliced HIV RNA (HIV UsRNA), multiply spliced HIV RNA encoding tat and rev (HIV MsRNA), and HIV DNA. Tonsil biopsy specimens from viremic patients harbored high amounts of virions, which primarily stemmed from local production, as indicated by a strong correlation of extracellular tonsillar RNA with intracellular HIV-1 nucleic acid levels but not with plasma viremia, and as shown by phylogenetic analysis of clonal env sequences from lymphoid tissue and plasma. In patients receiving HAART, intracellular HIV UsRNA persisted at significantly decreased levels, whereas HIV MsRNA and lymphoid virion levels were depleted. Thus, residual lymphoid HIV-1 RNA in patients receiving HAART indicates attenuated viral transcription in HIV-1-infected cells that lack virion productio
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