How to protect a wind turbine from lightning

Techniques for reducing the chances of lightning damage to wind turbines are discussed. The methods of providing a ground for a lightning strike are discussed. Then details are given on ways to protect electronic systems, generating and power equipment, blades, and mechanical components from direct and nearby lightning strikes

Random Feature Models for Learning Interacting Dynamical Systems

Particle dynamics and multi-agent systems provide accurate dynamical models for studying and forecasting the behavior of complex interacting systems. They often take the form of a high-dimensional system of differential equations parameterized by an interaction kernel that models the underlying attractive or repulsive forces between agents. We consider the problem of constructing a data-based approximation of the interacting forces directly from noisy observations of the paths of the agents in time. The learned interaction kernels are then used to predict the agents behavior over a longer time interval. The approximation developed in this work uses a randomized feature algorithm and a sparse randomized feature approach. Sparsity-promoting regression provides a mechanism for pruning the randomly generated features which was observed to be beneficial when one has limited data, in particular, leading to less overfitting than other approaches. In addition, imposing sparsity reduces the kernel evaluation cost which significantly lowers the simulation cost for forecasting the multi-agent systems. Our method is applied to various examples, including first-order systems with homogeneous and heterogeneous interactions, second order homogeneous systems, and a new sheep swarming system

Fission Decay Widths for Heavy-Ion Fusion-Fission Reactions

Cross-section and neutron-emission data from heavy-ion fusion-fission reactions are consistent with a Kramers-modified statistical model which takes into account the collective motion of the system about the ground state; the temperature dependence of the location of fission transition points; and the orientation degree of freedom. We see no evidence to suggest that the nuclear viscosity departs from the surface-plus-window dissipation model. The strong increase in the nuclear viscosity above a temperature of ~1 MeV deduced by others is an artifact generated by an inadequate fission model.Comment: 14 pg, 6 fig, submitted to Physical Revie

Flow-through Capture and in Situ Amplification Can Enable Rapid Detection of a Few Single Molecules of Nucleic Acids from Several Milliliters of Solution

Detecting nucleic acids (NAs) at zeptomolar concentrations (few molecules per milliliter) currently requires expensive equipment and lengthy processing times to isolate and concentrate the NAs into a volume that is amenable to amplification processes, such as PCR or LAMP. Shortening the time required to concentrate NAs and integrating this procedure with amplification on-device would be invaluable to a number of analytical fields, including environmental monitoring and clinical diagnostics. Microfluidic point-of-care (POC) devices have been designed to address these needs, but they are not able to detect NAs present in zeptomolar concentrations in short time frames because they require slow flow rates and/or they are unable to handle milliliter-scale volumes. In this paper, we theoretically and experimentally investigate a flow-through capture membrane that solves this problem by capturing NAs with high sensitivity in a short time period, followed by direct detection via amplification. Theoretical predictions guided the choice of physical parameters for a chitosan-coated nylon membrane; these predictions can also be applied generally to other capture situations with different requirements. The membrane is also compatible with in situ amplification, which, by eliminating an elution step enables high sensitivity and will facilitate integration of this method into sample-to-answer detection devices. We tested a wide range of combinations of sample volumes and concentrations of DNA molecules using a capture membrane with a 2 mm radius. We show that for nucleic acid detection, this approach can concentrate and detect as few as ∼10 molecules of DNA with flow rates as high as 1 mL/min, handling samples as large as 50 mL. In a specific example, this method reliably concentrated and detected ∼25 molecules of DNA from 50 mL of sample

Setting Agricultural Research Priorities: Lessons from the CGIAR Study

The Consultative Group on International Agfi-cultural Research (CGIAR) is .1 loose BSSOCtft' lion of 40 donor agencies who provide about 250 million dollars annually to support international agricultural research on developing country problems in 18 institutes. The CGIAR is a relatively small actor on the global scene, representing less than 5% of agricultural research expenditures in developing countries and less than 2% of global public seclor expenditure on agricultural research (Gryseels and Anderson). Therefore, it has always had to be selective in choosing the nature and focus of the research it supports. Priority setting and advice on resource allocation is provided by an independent Technical Advisory Committee (TAC). In this paper we provide a brief review of TAC's approaches to priority setting before focusing on their most recent exercise completed in 1992. This effort was by far the most comprehensive attempt io use quantitative analysis to identify priorities and link them to resource allocation. The approach described in TAC/CGIAR (1992) is best characterized as a modified congruence approach or scoring model, using a spreadsheet The paper concludes with a critical appraisal of the strengths and weaknesses of the TAC approach relative lo other approaches

Pollution Abatement from Cattle Feedlots in Northeastern Colorado and Nebraska

Climatic factors, feedlot runoff, and organic material in the runoff were evaluated in experimental and commercial feedlots. The effects of slope, stocking rates, terraces, basins, and holding ponds were evaluated to obtain the best controls for containing runoff. In eastern Nebraska, 70 cm annual precipitation produces 23 cm of runoff; whereas, in northeastern Colorado, 37 cm annual precipitation gives only 5.5 cm of runoff. Large applications of runoff liquid, up to 91 cmon grass-Ladino and 76 cm on corn, in Nebraska did not decrease yields; however, in northeastern Colorado, the concentrated high-salt runoff required dilution before direct application to crops. The organic manure-soil interface severely restricts the movement of water, nitrates, organic substances, and air into the soil beneath feedlots. The amounts of N03-N in soil cores taken from Nebraska feedlots and croplands ranked as follows: abandoned feedlots\u3e feedlot cropland\u3e upland feedlots\u3e river valley feedlots\u3e manure mounds\u3e alfalfa\u3e grassland. Feedlots contribute NH3, amines, carbonyl sulfide, H2S, and other unidentified substances to the atmosphere. Ammonia and amine can be scavenged from the air by green plants and water bodies. Anaerobic conditions in feedlots are conducive to the production of carbonyl sulfide, H2S, and amines. Management practices, such as good drainage, that enhance aeration will decrease the evolution of these compounds

Exploring the Zone of Tolerance for Internal Customers in IT-Enabled Call Centers

Today, call center employees’ service encounters with external customers are extensively supported with modern information technology (IT). However, prior research on service quality and zone of tolerance (ZOT) focuses primarily on external customers with little attention paid to how internal customers (e.g., service employees) respond to services provided by internal functions, particularly IT function that supports employees’ IT use. Drawing on theory of administrative behavior and IT success literature, we conducted a study at a call center of a telecommunications firm and found that the impact of internal IT service quality (ITSQ) on employees’ service quality (ESQ) to external customers, as well as on their satisfaction with and use of the deployed technology, exhibits a positive diminishing pattern as ITSQ increases from below to within and to above the ZOT. We also found that ITSQ’s impact on ESQ employees\u27 satisfaction with technology changes more dramatically around adequate service level than desired service level. Finally, we show that call center employees’ satisfaction with technology partially mediates ITSQ’s impact on ESQ. Besides adding to the service and IT literature, our findings suggest that managers should understand internal customers’ different levels of expectations toward internal IT service and the differential performance impacts of those levels