Noise characteristics of upper surface blown configurations: Analytical Studies

Noise and flow results of upper surface blown configurations were analyzed. The dominant noise source mechanisms were identified from experimental data. From far-field noise data for various geometric and operational parameters, an empirical noise prediction program was developed and evaluated by comparing predicted results with experimental data from other tests. USB aircraft compatibility studies were conducted using the described noise prediction and a cruise performance data base. A final design aircraft was selected and theory was developed for the noise from the trailing edge wake assuming it as a highly sheared layer

Rates of denitrification as influenced by irrigation

Non-Peer ReviewedThe rate of denitrification, using the acetylene blockage method, was determined before and after irrigation at two sites; at Birsay on a clay-loam soil and at Outlook on a sandy soil. At Birsay, 110 kg N/ha as urea was applied 10 days before seeding and an additional 4 kg N/ha as ammonium phosphate at time of seeding. At Outlook, 50 kg N/ha as ammonium nitrate was applied just before seeding. Before irrigation, the rate of denitrification at both sites was almost undetectable. A sharp increase in the rate, however, occurred at both sites within a few hours after irrigation (approximately 25 mm) and lasted for approximately 24 hrs and 12 hrs at Birsay and Outlook, respectively. At the time of maximum activity, the losses of N (N2O and N2) were estimated to be 50 g ha-1 hr-1 and 3 g ha-1 hr-1 at Birsay and Outlook, respectively. The total amount of N lost per irrigation cycle, due to denitrification, at Birsay and Outlook were calculated to be 730 g ha-1 and 21g ha-1, respectively. The difference in the amount of N2O evolution at the two sites is partially attributed to the difference in soil type. The water holding capacity at Outlook is lower as compared with the soil at Birsay. Subsequently, the degree of anaerobic conditions, a pre-requisite for denitrification, will be less at Outlook. A lag period of 20 hrs occurred between the application of water and the maximum evolution of N2O of incubated soil cores. This was determined by analyzing incubated soil cores repeatedly over a period of 48 hrs. As the increase in denitrification at Birsay lasted for 24 hrs after the application of water, the maximum rate of denitrification did occur under those field conditions at Birsay. At Outlook, however, where the increase in denitrification only lasted for 12 hrs, the maximum rate of denitrification was not obtained under the existing field conditions. There were 10 irrigation and 7 precipitation events which caused denitrification. According to the percentage of the landform elements and its proper denitrification activity, the total N lost per year at Birsay was estimated to be 120 kg ha-1

Nitrogen accumulation by pea as affected by topography

Non-Peer ReviewedField peas grown under normal field conditions are exposed to variable soil and environmental conditions that will affect both crop yield and nitrogen (N) uptake. Topography and slope position may play an important role in governing soil and environmental factors that influence N accumulation. In 1991, a field experiment was initiated to examine the effects of landscape position on the yield and N accumulation by field pea (var. Marofat). A two-hectare site was located in the Black Soil Zone on land with gently sloping to roughly undulating slopes (2-5 %). Six landform elements were identified at the site location. The site was managed at a farm scale using typical cultural practices. Spring levels of inorganic nitrogen (NO3 + NH4) ranged from 19.0 to 57.4 kg/ha (0-60 cm depth). Differences in levels of inorganic nitrogen between landform elements were observed (p = 0.03). Volumetric moisture content of the soil (0-120 cm) was consistently highest in footslopes throughout the growing season. Water stress was not a limiting factor to plant growth in any landform until 50-55 days after planting. Total yield (seed + straw) of the pea crop ranged from 2310 to 8100 kg/ha while seed yield varied from 960 to 3940 kg/ha. Significant differences between landforms were detected for total yield (p = 0.02) but not seed yield. Seed nitrogen content ranged from 31-133 kg/ha but no differences were observed between landforms

Rates of denitrification as influenced by irrigation

Non-Peer ReviewedThe rate of denitrification, using the acetylene blockage method, was determined before and after irrigation at two sites; at Birsay on a clay-loam soil and at Outlook on a sandy soil. At Birsay, 110 kg N/ha as urea was applied 10 days before seeding and an additional4 kg N/ha as ammonium phosphate at time of seeding. At Outlook, 50 kg N/ha as ammonium nitrate was applied just before seeding. Before irrigation, the rate of denitrification at both sites was almost undetectable. A sharp increase in the rate, however, occurred at both sites within a few hours after irrigation (approximately 25 mm) and lasted for approximately 24 hrs and 12 hrs at Birsay and Outlook, respectively. At the time of maximum activity the losses of N (N2O and N2) were estimated to be 50 g ha-1 hr-1 and 3 g ha-1 hr-1 at Birsay and Outlook, respectively. The total amount of N lost per irrigation cycle due to denitrification at Birsay and Outlook were calculated to be 730 g ha-1 and 21 g ha-1, respectively. The difference in the amount of N2O evolution at the two sites is partially attributed to the difference in soil type. The water holding capacity at Outlook is lower as compared with the soil at Birsay. Subsequently, the degree of anaerobic conditions, a prerequisite for denitrification, will be less at Outlook. A lag period of 20 hrs occurred between the application of water and the maximum evolution of N2O of incubated soil cores. This was determined by analyzing incubated soil cores repeatedly over a period of 48 hrs. As the increase in denitrification at Birsay lasted for 24 hrs after the application of water, the maximum rate of denitrification did occur under those field conditions at Birsay. At Outlook, however, where the increase in denitrification only lasted for 12 hrs, the maximum rate of denitrification was not obtained under the existing field conditions. There were 10 irrigation and 7 precipitation events which caused denitrification. According to the percentage of the landform elements and its proper denitrification activity, the total N lost per year at Birsay was estimated to be 120 kg ha-1

Frictional behaviour of simulated muscovite fault gouge at shear strains up to 120 and temperatures of 20-600 ºC

see Abstract Volum

A stochastic model for the evolution of the web allowing link deletion

Recently several authors have proposed stochastic evolutionary models for the growth of the web graph and other networks that give rise to power-law distributions. These models are based on the notion of preferential attachment leading to the ``rich get richer'' phenomenon. We present a generalisation of the basic model by allowing deletion of individual links and show that it also gives rise to a power-law distribution. We derive the mean-field equations for this stochastic model and show that by examining a snapshot of the distribution at the steady state of the model, we are able to tell whether any link deletion has taken place and estimate the link deletion probability. Our model enables us to gain some insight into the distribution of inlinks in the web graph, in particular it suggests a power-law exponent of approximately 2.15 rather than the widely published exponent of 2.1

Journal off Mechanical Design The Application of Curvature Theory to the Trajectory Generation Problem of Robot Manipulators

This paper illustrates a new application of planar curvature theory to the geometric problem of trajectory generation by a two-link manipulator. The theory yields the instantaneous speed ratio, and the rate of change of the speed ratio, which correspond to the geometry of a desired point trajectory. Separate from the purely geometric speed ratio problem (i.e., the coordination problem) is the time based problem of controlling the joint rates in order to move with the specified path variables. Introduction A rigid body, constrained to move in a plane with N independent degrees of freedom, where 1 < N < 3, is known as a planar TV-parameter motion, denoted by M N . This paper discusses the arm-subassembly of a planar manipulator, whose terminal link is a planar M 2 motion. The purpose is to illustrate a new application of classical curvature theory to the problem of trajectory generation by a multi-degree-of-freedom rigid body system, in this case a planar robot manipulator. Previously, curvature theory has been applied to the dimensional synthesis of planar mechanisms. The new application of the theory illustrated here is a problem of motion synthesis by industrial manipulators

Organization of networks with tagged nodes and biased links: a priori distinct communities. The case of Intelligent Design Proponents and Darwinian Evolution Defenders

Among topics of opinion formation it is of interest to observe the characteristics of networks with a priori distinct communities. As an illustration, we report on the citation network(s) unfolded in the recent decades through web available works belonging to selected members of the Neocreationist and Intelligent Design Proponents (IDP) and the Darwinian Evolution Defenders (DED) communities. An adjacency matrix of tagged nodes is first constructed; it is not symmetric. A generalization of considerations pertaining to the case of networks with biased links, directed or undirected, is thus presented. The main characteristic coefficients describing the structure of such partially directed networks with tagged nodes are outlined. The structural features are discussed searching for statistical aspects, equivalence or not of subnetworks through the degree distributions, each network assortativity, the global and local clustering coefficients and the Average Overlap Indices. The various closed and open triangles made from nodes, moreover distinguishing the community, are especially listed to calculate the clustering characteristics. The distribution of elements in the rectangular submatrices are specially examined since they represent inter-community connexions. The emphasis being on distinguishing the number of vertices belonging to a given community. Using such informations one can distinguish between opinion leaders, followers and main rivals and briefly interpret their relationships through psychological-like conditions intrinsic to behavior rules in either community. Considerations on other controversy cases with similar social constraints are outlined, as well as suggestions on further, more general, work deduced from our observations on such networks.Comment: 40 pages, 61 references, 7 Tables, 11 Figures, 2 Appendices (giving the adjacency matrices

A One Health Framework for the Evaluation of Rabies Control Programmes: A Case Study from Colombo City, Sri Lanka

<div><p>Background</p><p>One Health addresses complex challenges to promote the health of all species and the environment by integrating relevant sciences at systems level. Its application to zoonotic diseases is recommended, but few coherent frameworks exist that combine approaches from multiple disciplines. Rabies requires an interdisciplinary approach for effective and efficient management.</p><p>Methodology/Principal Findings</p><p>A framework is proposed to assess the value of rabies interventions holistically. The economic assessment compares additional monetary and non-monetary costs and benefits of an intervention taking into account epidemiological, animal welfare, societal impact and cost data. It is complemented by an ethical assessment. The framework is applied to Colombo City, Sri Lanka, where modified dog rabies intervention measures were implemented in 2007. The two options included for analysis were the control measures in place until 2006 (“baseline scenario”) and the new comprehensive intervention measures (“intervention”) for a four-year duration. Differences in control cost; monetary human health costs after exposure; Disability-Adjusted Life Years (DALYs) lost due to human rabies deaths and the psychological burden following a bite; negative impact on animal welfare; epidemiological indicators; social acceptance of dogs; and ethical considerations were estimated using a mixed method approach including primary and secondary data. Over the four years analysed, the intervention cost US $1.03 million more than the baseline scenario in 2011 prices (adjusted for inflation) and caused a reduction in dog rabies cases; 738 DALYs averted; an increase in acceptability among non-dog owners; a perception of positive changes in society including a decrease in the number of roaming dogs; and a net reduction in the impact on animal welfare from intermediate-high to low-intermediate.</p><p>Conclusions</p><p>The findings illustrate the multiple outcomes relevant to stakeholders and allow greater understanding of the value of the implemented rabies control measures, thereby providing a solid foundation for informed decision-making and sustainable control.</p></div