170,467 research outputs found
Dairy Manure Impact On Soil Phosphorous, Nitrogen, and Salt Accumulation In An Oat-maize Rotation In Southwestern United States
No full textThe effect of manure applications on crop yield and the soil environment is becoming an ever more important issue in Arizona, where dairy herds are increasing and crop acreage is being lost to tile roofs. A field study was initiated in Central Arizona to evaluate the impact of dairy manure applications on soil phosphorus, nitrogen and salt levels after four seasons of an oat/maize rotation. Additionally, the applicability of Natural Resource Conservation Service's (NRCS) Phosphorus Index (P-Index,) tool was assessed. An inorganic fertilizer treatment was used as a control. Nitrogen (N)-based rate applications of dairy manure took place semi-annually to an oat (fall) and maize (spring) rotation for four consecutive cropping seasons from 2002 through 2004. After two years and four cropping seasons, treatment effects on soil nitrate (NO(3)-N) levels were evident only in the top 0.3 m and concentrations never exceeded 10 mg kg(-1). The salt content of the soil also increased, with electroconductivity (EC) values nearly doubling at many depths. Manured treatments, both composted and fresh, generally produced lower crop yields than control treatment, although differences were significant in only one season for each crop. Phosphate (PO(4)-P levels in the soil (0 to 2.1 m depth) increased dramatically in the compost and manure treatments from 233 to 583 and 182 to 580 kg PO(4)-P ha(-1), respectively. Phosphate levels in the control treatment increased only 86 kg ha(-1) during the same time period from 28 to 114 kg ha(-1). From an agronomic standpoint, the amount of PO(4)-P in the manure and compost treatments was beyond the optimum requirement for crop growth and created a potential environmental hazard for the loss of phosphorus (P) due to erosion and runoff However, when applying the NRCS P-Index tool to this field to determine the potential risk of the movement of P offsite, it was found that no restriction would be imposed on the application of any fertilizer (organic or inorganic) because the P-threshold level would not have been met. These results may indicate a need to adjust the P-Index presently used in Arizona
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Recent Advances in Modeling and Experiments of Kevlar Ballistic Fibrils, Fibers, Yarns and Flexible Woven Textile Fabrics – A Review
No full textAuthor's final draft after peer reviewBallistic impact onto flexible woven textile fabrics is a complicated multi-scale problem given
the structural hierarchy of the materials, anisotropic material behavior, projectile geometry-fabric
interactions, impact velocity and boundary conditions. Although this subject has been an active
area of research for decades, the fundamental mechanisms such as material failure, dynamic
response, multi-axial loading occurring at the lower length scales during impact are not well
understood. This paper reviews the recent advances in modeling and experiments of Kevlar
ballistic fibrils, fibers, yarns and flexible woven textile fabrics pertinent to the deformation modes
occurring during impact and serves to identify topics worthy of further investigation that will
advance the basic understanding of the phenomena governing transverse impact. This review also
explores on aspects such as homogeneous versus heterogeneous behavior of yarns consisting of
individual fibers and the inelastic transverse behavior of the fiber which is not considered in the
previous review papers on this topic.University of Delaware. Center for Composite Materials.University of Delaware. Department of Mechanical Engineering.University of Delaware. Department of Materials Science and Engineering.University of Delaware. Department of Civil and Environmental Engineering
Mitomycin C in highly myopic eyes - Author reply
No full textOphthalmology. 2005 Feb;112(2):208-18; discussion 219.
Mitomycin C modulation of corneal wound healing after photorefractive keratectomy in highly myopic eyes.
Gambato C, Ghirlando A, Moretto E, Busato F, Midena E.
SourceRefractive Surgery Service and Antimetabolite Therapy Research Unit, Department of Ophthalmology, University of Padova, Padova, Italy.
Abstract
PURPOSE: To evaluate the role of topical mitomycin C in corneal wound healing (CWH) after photorefractive keratectomy (PRK) in highly myopic eyes.
DESIGN: Prospective, double-masked, randomized clinical trial.
PARTICIPANTS: Seventy-two eyes of 36 patients affected by high (>7 diopters) myopia.
METHODS: In each patient, one eye was randomly assigned to PRK with intraoperative topical 0.02% mitomycin C application, and the fellow eye was treated with a placebo. Postoperatively, mitomycin C-treated eyes received artificial tears (3 times daily, tapered in 3 months), whereas the fellow eye was treated with fluorometholone sodium 2% and artificial tears (3 times daily, tapered in 3 months).
MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), contrast sensitivity, manifest refraction, and biomicroscopy. Contrast sensitivity was determined using the Pelli-Robson chart. Corneal confocal microscopy documented CWH.
RESULTS: Mean follow-up was 18 months (range, 12-36). No side effects or toxic effects were documented. At 12-month follow-up examination, UCVAs (logarithm of the minimum angle of resolution) were 0.4+/-0.48 and 0.5+/-0.53 (P = .03) in mitomycin C-treated eyes and corticosteroid-treated eyes, respectively. At 1 year, corneal haze developed in 20% of corticosteroid-treated eyes, versus 0% of mitomycin C-treated eyes. At 12, 24, and 36 months, corneal confocal microscopy showed activated keratocytes and extracellular matrix significantly more evident in untreated eyes (Ps = 0.004, 0.024, and 0.046, respectively).
CONCLUSION: Topical intraoperative application of 0.02% mitomycin C can reduce haze formation in highly myopic eyes undergoing PRK.
Comment in
Ophthalmology. 2006 Feb;113(2):357; author reply 357-8
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Design and development of heat exchanger based on open cell metal foam / Ananthasayanam Subramani Sharath
No full textThe fluid flowing through pipes or ducts is commonly used in heating and were the liquids or the gas. The fluid in this type of flow is usually forced by a blower to bring about the preferred heat transfer. The equipment’s that ease this process are the Heat Exchangers. The Copper metal foams with 60 PPI (Pores Per Inch) was chosen to develop the Heat Exchanger. The primary objective of the research in developing a compact metal foam heat exchanger in different configuration was achieved. Firstly, the Design 1 was a type of Heat Exchanger that the copper metal foams and the aluminum fins are arranged consecutively and closely packed. Secondly, the Design 2 was a type of Heat Exchanger that the pair of aluminum fins and foams were arranged with air gap of 5mm in between. The Novelty of this research lies with the Different design and the configuration of the metal foam arranged in the housing with the maximum pore density of 60 PPI. The Experimental Investigation of both the designs were studied separately based on the Velocity Profile, Pressure Drop, Heat transfer coefficient and the Temperature Difference. The effects of each mentioned above were studied and analyzed by varying velocity from 0.8m/s to 2.3m/s. The experiments were conducted under steady state conditions of maintaining the constant room temperature and the constant heat flux of 50˚C. The Heat transfer characteristics of each localized points from H11 to H51 and H12 to H52 in the heat exchanger for both the design1 and 2 were studied thoroughly. The average Nusselt number for both designs was evaluated based on the average heat transfer coefficient and has been compared with the analytical equation and the previous study
A Multi-Language Comparison of Influences on Author Verification using Character N-Grams
No full textWe create a new multi-language corpus for author verification based on Wikipedia talkpages, and evaluate the influence that differences in topic and time have on character n-gram author profiles. Topic alignment between two texts is found to increase author verification precision, and an authors writing style is found to change over time, but not more significantly after 3 years than after 1 year.Information ArchitectureWISElectrical Engineering, Mathematics and Computer Scienc
A 0.12mm<sup>2</sup> Wien-Bridge Temperature Sensor with 0.1°C (3σ) Inaccuracy from -40°C to 180°C
No full text Resistor-based temperature sensors can achieve much higher resolution and energy efficiency than conventional BJT-based sensors [1], but they typically occupy more area (> 0.25 mm 2 ) and have lower operating temperatures (le 125 {circ} {C}) [2]-[4]. This work describes a 0.12mm 2 resistor-based sensor that uses a Wien-bridge (WB) filter to achieve 0.1 {circ} {C} (3 sigma) inaccuracy from - 40 {circ} {C} to 180 {circ} {C}. Compared to a state-of-the-art WB sensor [4], it occupies 6 × less area and achieves comparable relative accuracy over a 76% wider operating range. Session 10.3 Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic
A ±25A Versatile Shunt-Based Current Sensor with 10kHz Bandwidth and ±0.25% Gain Error from -40°C to 85°C Using 2-Current Calibration
No full textAccurate current sensing is critical in many industrial applications, such as battery management and motor control. Precise shunt-based current sensors have been reported with gain errors of less than 1% over the industrial temperature range (-40°C to 85°C) [1]–[4]. However, since they are intended for coulomb counting, their bandwidth is limited to a few tens of Hz, making them unsuitable for battery impedance or motor-current sensing. This paper presents a current sensor with a wide (10kHz) bandwidth and a tunable temperature compensation scheme (TCS), which allows it to be flexibly used with different types of shunts while maintaining high accuracy. A low-cost room-temperature calibration scheme is proposed to optimize gain flatness over temperature by exploiting the shunt's self-heating at large currents. Over the industrial temperature range and a ±25A current range, it achieves state-of-the-art gain error (±0.25%) with both low-cost PCB and stable metal-alloy shunts.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic
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