957 research outputs found
Modeling groundwater with ocean and river interaction
We develop and implement the groundwater model, Saturated/Unsaturated Flow and Transport in 3D (SUFT3D), to integrate water quantity/quality data and simulations with models of other hydrologic cycle components, namely, rivers and the ocean. This work was done as part of the Sea Air Land Modeling Operational Network (SALMON) project supported by the IBM International Foundation through its Environmental Research Program. The first research steps, presented here, address the simulation of typical hydrologic conditions to demonstrate SUFT3D's effectiveness and accuracy. The theory behind the modeling of seawater intrusion and groundwater-river interaction is summarized along with the numerical methods and characteristics of SUFT3D. The code was applied to different, increasingly complex scenarios: confined to unconfined conditions, local to regional scale, homogeneous to increasing heterogeneity, two- to three-dimensional. Of particular interest were the impacts of different boundary conditions and influence of river interactions on seawater intrusion. Results are illustrated, discussed, and compared, when possible, to those in the literature. Simulating groundwater exchange between both the river and the ocean has provided interesting results that better depict the dynamics of flow and transport in coastal zone groundwater systems
Energy-saving optimization method for point-to-point trajectories planned via standard primitives in 1-DoF mechatronic systems
AbstractIn this work, an analytical methodology to minimize the energy expenditure of mechatronic systems performing point-to-point (PTP) trajectories based on well-known motion primitives is developed and validated. Both PTP trajectory profiles commonly used in industrial motor drives and more complex ones are investigated. Focusing on generic 1-DoF mechatronic systems moving a constant inertia load (e.g., elevators, cranes, CNC machines, Cartesian axis) and possibly equipped or retrofitted with regenerative devices, the consumed energy formulation is firstly derived. Then, the analytical optimization considering all the selected PTP trajectory profiles is computed and a generic closed-form solution is determined. Finally, numerical and experimental evaluations are done showing the effectiveness of the theoretical results and proposed methodology. In addition, all the different trajectories are compared with respect to energy consumption
On the trajectory planning for energy efficiency in industrial robotic systems
In this paper, we present an approach for the minimum-energy trajectory planning in industrial robotic systems. The method is based on the dynamic and electro-mechanical modeling of one-degree-of-freedom systems and the derivation of the energy formulation for standard point-to-point trajectories, as, for instance, trapezoidal and cycloidal speed profiles. The proposed approach is experimentally validated on two robotic systems, namely a linear axis of a Cartesian manipulator built in the 1990\u2019s, and a test bench composed of two servomotors directly connected or coupled by means of a planetary gear. During the tests, the electrical power expended by the systems is measured and integrated over time to compute the energy consumption for each trajectory. Despite the limitations of the energy measurement systems, the results reveal a trend in agreement with the theoretical calculations, showing the possibility of applying the method for enhancing the performance of industrial robotic systems in terms of energy consumption in point-to-point motions
An intelligence-sharing continuum : next generation requirements for U.S. counterterrorism efforts
CHDS State/LocalThe September 11, 2001 terrorist attacks were a major catalyst for intelligence reform in the United States. Since this date, most government agencies have strived to evolve and advance in this capacity. One such way has been through the development of multi-agency, multi-disciplinary intelligence centers, such as the National Counterterrorism Center, the Interagency Threat Assessment and Coordination Group, and the 72 state and major urban area fusion centers established throughout the nation. However, despite the changes that have occurred throughout the U.S. intelligence and law enforcement communities, significant issues still remain that are impeding the creation and flow of actionable intelligence to support domestic counterterrorism efforts. This has been identified from research conducted on numerous sources. Several policy, technological, cultural and political challenges exist, all contributing to the less-than-perfect nature of the United States' existing counterterrorism framework. This thesis aims to identify potential solutions that leverage existing intelligence operations to promote an intelligence-sharing continuum across all tiers of U.S. government. The author provides an analysis of specific, priority issues that require fixing within our nation's counterterrorism system, and provides evidence-based recommendations to improve the capability and value of existing intelligence support structures and further-develop the desired intelligence-sharing continuum.http://archive.org/details/anintelligencesh109455507Senior Intelligence Analyst, Boston Police Department, Boston, MAApproved for public release; distribution is unlimited
Effects often overlooked in lipid oxidation in oil-in-water emulsions:Agitation conditions and headspace-to-emulsion ratio
The effects of the agitation conditions and headspace-to-emulsion volume ratio on lipid oxidation in emulsions can be considerable, but have not been systematically investigated yet. In the current paper, lipid oxidation was monitored in model oil-in-water (O/W) emulsions at pH 4.0 and 25°C in the presence of 200 μM iron sulfate. The formation of primary (conjugated dienes and hydroperoxides) and secondary (p-anisidine value and TBARS) oxidation products confirmed that using rotating or shaking devices doubled the rate of oxidation product formation compared to a non-agitated system, as a result of enhanced oxygen transfer. Furthermore, we found that a higher headspace-to-emulsion volume ratio at least doubled the rate of lipid oxidation due to a higher amount of oxygen available per mass of oil, which is in agreement with the kinetics of the reaction. This indicates that the variation in literature data on lipid oxidation in emulsions can be attributed to differences in mixing conditions and volume ratios. These factors are crucial and should be reported systematically along with the agitation conditions, and sampling method. This will enable a better comparison of literature information.</p
Prevalence of and factors associated with human cysticercosis in 60 villages in three provinces of Burkina Faso
Background : Taenia solium, a zoonotic infection transmitted between humans and pigs, is considered an emerging infection in Sub-Saharan Africa, yet individual and community-level factors associated with the human infection with the larval stages (cysticercosis) are not well understood. This study aims to estimate the magnitude of association of individual-level and village-level factors with current human cysticercosis in 60 villages located in three Provinces of Burkina Faso.
Methodology/Principal Findings : Baseline cross-sectional data collected between February 2011 and January 2012 from a large community randomized-control trial were used. A total of 3609 individuals provided serum samples to assess current infection with cysticercosis. The association between individual and village-level factors and the prevalence of current infection with cysticercosis was estimated using Bayesian hierarchical logistic models. Diffuse priors were used for all regression coefficients. The prevalence of current cysticercosis varied across provinces and villages ranging from 0% to 11.5%. The results obtained suggest that increased age, being male and consuming pork as well as a larger proportion of roaming pigs and percentage of sand in the soil measured at the village level were associated with higher prevalences of infection. Furthermore, consuming pork at another village market had the highest increased prevalence odds of current infection. Having access to a latrine, living in a household with higher wealth quintiles and a higher soil pH measured at the village level decreased the prevalence odds of cysticercosis.
Conclusions/Significance : This is the first large-scale study to examine the association between variables measured at the individual-, household-, and village-level and the prevalence odds of cysticercosis in humans. Factors linked to people, pigs, and the environment were of importance, which further supports the need for a One Health approach to control cysticercosis infection
A parametric approach for evaluating the stability of agricultural tractors using implements during side-slope activities
A methodological approach for evaluating a priori the stability of agricultural vehicles equipped with different mounted implements and operating on sloping hillsides is shown here. It uses a Matlab simulator in its first phase and, subsequently, the Response Surface Modelling (RSM) to evaluate the coefficients of a set of regression equations able to account for the Type-I and Type-II stability of the whole vehicle (tractor + implement with known dimensions and mass).
The regression equations can give reliable punctual numeric estimations of the minimum value of the Roll Stability Index (RSI) and can verify the existence of a Type-I equilibrium without the need of using the simulator or knowing any detail about the model implemented in it. The same equations can also be used to generate many intuitive graphs (\u201cequilibrium maps\u201d) useful to verify quickly the possible overturning of the vehicle.
A case-study concerning a 4-wheel drive articulated tractor is then presented to show the potential of the approach and how using its tools. The tractor has been studied in three scenarios, differing on where the implement has to be connected to the tractor (1: frontally; 2: frontally-laterally; 3: in the back). After performing a series of simulations, a set of polynomial models (with 6 independent variables) has been created and verified. Then, these models were used, together with the related equilibrium maps, to predict the stability of 8 implements for scenario 1, 7 implements for scenario 2, and 3 implements for scenario 3, evidencing in particular the danger of using a lateral shredder with a mass greater than 245 kg.
The proposed approach and its main outcomes (i.e., the regression equations and the equilibrium maps) can give an effective contribution to the preventive safety of the tractor driver, so it could be useful to integrate it in the homologation procedures for every agricultural vehicle and to include the resulting documentation within the tractor logbook
Chemical Stability of α-Tocopherol in Colloidal Lipid Particles with Various Morphologies
Colloidal lipid particles (CLPs) are promising encapsulation systems for lipophilic bioactives, such as oil-soluble antioxidants that are applied in food and pharmaceutical formulations. Currently, there is no clear consensus regarding the relation between particle structure and the chemical stability of such bioactives. Using α-tocopherol as a model antioxidant, it is shown that emulsifier type (Tween 20 or 40, or sodium caseinate) and lipid composition (tripalmitin, tricaprylin, or combinations thereof) modulated particle morphology and antioxidant stability. The emulsifier affects particle shape, with the polysorbates facilitating tripalmitin crystallization into highly ordered lath-like particles, and sodium caseinate resulting in less ordered spherical particles. The fastest degradation of α-tocopherol is observed in tripalmitin-based CLPs, which may be attributed to its expulsion to the particle surface induced by lipid crystallization. This effect is stronger in CLPs stabilized by Tween 40, which may act as a template for crystallization. This work not only shows how the architecture of CLPs can be controlled through the type of lipid and emulsifier used, but also gives evidence that lipid crystallization does not necessarily protect entrapped lipophilic bioactives, which is an important clue for encapsulation system design. Practical Applications: Interest in enriching food and pharmaceutical products with lipophilic bioactives such as antioxidants through encapsulation in lipid particles is growing rapidly. This research suggests that for efficient encapsulation, the particle architecture plays an important role; to tailor this, the contribution of both the lipid carrier and the emulsifier needs to be considered.</p
Enhancing Energy Efficiency of a 4-DOF Parallel Robot Through Task-Related Analysis
Enhancing energy efficiency is one of the main challenges of today\u2019s industrial robotics and manufacturing technology. In this paper a task-related analysis of the energetic performance of a 4-DOF industrial parallel robot is presented, and the optimal location of a predefined task with respect to the robot workspace is investigated. An optimal position of the task relative to the robot can indeed reduce the actuators\u2019 effort and the energy consumption required to complete the considered operation. The dynamic and electro-mechanical models of the manipulators are developed and implemented to estimate the energy consumption of a parametrized motion with trapezoidal speed profile, i.e., a pick-and-place operation. Numerical results provide energy consumption maps that can be adopted to place the starting and ending points of the task in the more energy-efficient location within the robot workspace
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