4,495 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Characterisation and calibration of low-cost PM sensors at high temporal resolution to reference grade performances - dataset
Full text linkThis repository contains the data used for the analysis of the paper "Characterisation and calibration of PM sensors at high temporal resolution to reference grade performances" submitted to Heliyon and available as a pre-print:
Bulot, Florentin M. J. and Ossont, Steven J. and Morris, Andrew and Basford, Philip J. and Easton, Natasha H. C. and Mitchell, Hazel L. and Foster, Gavin L. and Cox, Simon J. and Loxham, Matthew, Characterisation and Calibration of Low-Cost Pm Sensors at High Temporal Resolution to Reference-Grade Performance. Available at SSRN: https://ssrn.com/abstract=4360707 or http://dx.doi.org/10.2139/ssrn.4360707
The code used to conduct the data analysis is available at https://doi.org/10.5281/zenodo.7261417
.
The files are available in .csv and in .rds (for R) formats. For details about the measurement equipment used
during this study, please refer to the methods section of the paper.
Description of the files.
202007_to_202107_nocs - contains the data from the low-cost sensors
It contains the following headers:
- "sensor" - sensor id
- "site" - name of the air quality monitor hosting the sensor
- "median_PM1" - PM1 mass concentration (ug/m3)
- "median_PM10" - PM10 mass concentration (ug/m3)
- "median_PM25" - PM25 mass concentration (ug/m3)
- "median_PM4" - PM4 mass concentration (ug/m3) (only available for SPS30)
- "median_n05" - particle number concentration (SPS30) of particles between 0.3um and 0.5um
- "median_n1" - particle number concentration (SPS30) of particles between 0.3um and 1um
- "median_n10" - particle number concentration (SPS30) of particles between 0.3um and 10um
- "median_n25" - particle number concentration (SPS30) of particles between 0.3um and 2.5um
- "median_n4" - particle number concentration (SPS30) of particles between 0.3um and 4um
- "median_gr03um" - particle number concentration (PMS5003) of particles >0.3um
- "median_gr05um" - particle number concentration (PMS5003) of particles >0.5um
- "median_gr100um" - particle number concentration (PMS5003) of particles >10um
- "median_gr10um" - particle number concentration (PMS5003) of particles >1um
- "median_gr25um" - particle number concentration (PMS5003) of particles >2.5um
- "median_gr50um" - particle number concentration (PMS5003) of particles >5um
- "median_pm100_cf1" - PM10 mass concentration with cf1 calibration for PMS5003
- "median_pm10_cf1" - PM1 mass concentration with cf1 calibration for PMS5003
- "median_pm25_cf1" - PM25 mass concentration with cf1 calibration for PMS5003
- "date" - date, format "yyyy-mm-dd HH:MM:SS GMT"
df_pm_2min - contains the PM mass concentration data from the Fidas 200S.
It contains the following headers:
- "PM2.5" - PM2.5 mass concentration (ug/m3) Fidas 200S
- "PM10" - PM10 mass concentration (ug/m3) Fidas 200S
- "PMtot" - PM total mass concentration (ug/m3) Fidas 200S
- "PM1" - PM1 mass concentration (ug/m3) Fidas 200S
- "date" - date, format "yyyy-mm-dd HH:MM:SS GMT"
df_weather_2min - contains the weather data from the Fidas 200S
It contains the following headers:
- "rh" - relative humidity (%)
- "dew_point_temperature" - dew point temperature (Celsius)
- "air_pressure" - Air pressure (hPa)
- "temperature" - temperature (Celsius)
- "date" - date, format "yyyy-mm-dd HH:MM:SS GMT
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
Effective shear speed in two-dimensional phononic crystals
No full textThe quasistatic limit of the antiplane shear-wave speed ('effective speed') c in 2D periodic lattices is studied. Two new closed-form estimates of c are derived by employing two different analytical approaches. The first proceeds from a standard background of the plane wave expansion (PWE). The second is a new approach, which resides in x-space and centers on the monodromy matrix (MM) introduced in the 2D case as the multiplicative integral, taken in one coordinate, of a matrix with components being the operators with respect to the other coordinate. On the numerical side, an efficient PWE-based scheme for computing c is proposed and implemented. The analytical and numerical findings are applied to several examples of 2D square lattices with two and three high contrast components, for which the new PWE and MM estimates are compared with the numerical data and with some known approximations. It is demonstrated that the PWE estimate is most efficient in the case of densely packed stiff inclusions, especially when they form a symmetric lattice, while in general it is the MM estimate that provides the best overall fitting accuracy.Peer reviewe
Elastodynamics of radially inhomogeneous spherically anisotropic elastic materials in the Stroh formalism
No full textA method is presented for solving elastodynamic problems in radially inhomogeneous elastic materials with spherical anisotropy, i.e. materials such that cijkl = cijkl(r) in a spherical coordinate system. The time harmonic displacement field u is expanded in a separation of variables form with dependence on described by vector spherical harmonics with r-dependent amplitudes. It is proved that such separation of variables solution is generally possible only if the spherical anisotropy is restricted to transverse isotropy with the principal axis in the radial direction, in which case the amplitudes are determined by a first-order ordinary differential system. Restricted forms of the displacement field, such as u admit this type of separation of variables solutions for certain lower material symmetries. These results extend the Stroh formalism of elastodynamics in rectangular and cylindrical systems to spherical coordinates.Peer reviewedReceived July 29, 2011; accepted September 16, 2011; published online December 23, 2011. Print publication date February 2012. Manuscript dated September 14, 2011
On the quasistatic effective elastic moduli for elastic waves in three-dimensional phononic crystals
No full textEffective elastic moduli for 3D solid-solid phononic crystals of arbitrary anisotropy and oblique lattice structure are formulated analytically using the plane-wave expansion (PWE) method and the recently proposed monodromy-matrix (MM) method. The latter approach employs Fourier series in two dimensions with direct numerical integration along the third direction. As a result, the MM method converges much quicker to the exact moduli in comparison with the PWE as the number of Fourier coefficients increases. The MM method yields a more explicit formula than previous results, enabling a closed-form upper bound on the effective Christoffel tensor. The MM approach significantly improves the efficiency and accuracy of evaluating effective wave speeds for high-contrast composites and for configurations of closely spaced inclusions, as demonstrated by three-dimensional examples.Peer reviewe
Analytical formulation of 3D dynamic homogenization for periodic elastic systems
No full textHomogenization of the equations of motion for a three dimensional periodic elastic system is considered. Expressions are obtained for the fully dynamic effective material parameters governing the spatially averaged fields by using the plane wave expansion (PWE) method. The effective equations are of Willis form [1] with coupling between momentum and stress and tensorial inertia. The formulation demonstrates that the Willis equations of elastodynamics are closed under homogenization. The effective material parameters are obtained for arbitrary frequency and wavenumber combinations, including but not restricted to Bloch wave branches for wave propagation in the periodic medium. Numerical examples for a 1D system illustrate the frequency dependence of the parameters on Bloch wave branches and provide a comparison with an alternative dynamic effective medium theory [2] which also reduces to Willis form but with different effective moduli.Peer reviewedReceived by the journal publisher November 28, 2011; accepted January 13, 2012; published online April 25, 2012. Manuscript dated January 16, 2012
Nonlinear shear wave interaction at a frictional interface: Energy dissipation and generation of harmonics
No full textAnalytical and numerical modelling of the nonlinear interaction of shear wave with a frictional interface is presented. The system studied is composed of two homogeneous and isotropic elastic solids, brought into frictional contact by remote normal compression. A shear wave, either time harmonic or a narrow band pulse, is incident normal to the interface and propagates through the contact. Two friction laws are considered and their influence on interface behavior is investigated : Coulomb's law with a constant friction coefficient and a slip-weakening friction law which involves static and dynamic friction coefficients. The relationship between the nonlinear harmonics and the dissipated energy, and their dependence on the contact dynamics (friction law, sliding and tangential stress) and on the normal contact stress are examined in detail. The analytical and numerical results indicate universal type laws for the amplitude of the higher harmonics and for the dissipated energy, properly non-dimensionalized in terms of the pre-stress, the friction coefficient and the incident amplitude. The results suggest that measurements of higher harmonics can be used to quantify friction and dissipation effects of a sliding interface.Peer reviewe
Goodbye to Projects? - Review of development interventions in Tanzania: From projects to livelihoods approaches
No full textApproaches to projects and development have undergone considerable change in the last decade with significant policy shifts on governance, gender, poverty eradication, and environmental issues. Most recently this has led to the adoption and promotion of the sustainable livelihood (SL) approach. The adoption of the SL approach presents challenges to development interventions including: the future of projects and programmes, and sector wide approaches (SWAPs) and direct budgetary support. This paper `A Review of Approaches to Development Interventions in Tanzania: From Projects to Livelihood Approaches¿ is the third in the series of the project working papers. This is the output of a literature review and semi-structured interviewing in Tanzania.Department for International Developmen
Identifying floral hosts of cerambycid beetles using palynology
Full text linkPollen is an important food source for many insects including the adults of beetles whose larvae are important forest pests. I quantified the distribution of pollen-feeding in adults of several species of long-horned beetles (Coleoptera: Cerambycidae). Palynivory by cerambycid beetles is common in the subfamily Lepturinae and occurs sporadically in Cerambycinae. The current knowledge of feeding in this group is inferred from floral host records, which are biased against tall trees because they are inaccessible to naturalists. I present a simplified palynological method for extracting and quantifying pollen from the frass of 21 species of beetles collected on flowers, with pheromone-baited panel traps, and at lights. I identified pollen grains to genus or species when possible and estimated abundances using calculations based on standardized markers added to samples. I found a higher abundance of pollen grains in the frass of palynivorous beetles collected on flowers than in the frass of beetles collected otherwise. I used the Shannon-Wiener Index to describe the diversity of pollen in the frass of beetles collected from flowers. There was high alpha diversity of pollen grains in the frass of Callimoxys sanguinicollis (Olivier) on Cornus drummondii C.A.Mey. (Cornaceae) and Molorchus bimaculatus Say on Cornus florida L. Next, I described the pollen taxa in the frass of palynivorous beetles collecting in traps and at lights by calculating the mean abundance and proportions of pollen taxa. I found Juglans nigra L. (Juglandaceae), Quercus L. (Fagaceae), and Vitis L. (Vitaceae) in frass from Anelaphus pumilus (Newman). Acer L. (Sapindaceae), Viburnum L. (Caprifoliaceae), and Quercus was found in frass from Cyrtophorus verrucosus (Olivier). I recorded Acer and Quercus pollen in the frass of Euderces pini (Olivier). Megacyllene caryae (Gahan) frass contained Quercus and Crataegus Tourn. (Rosaceae) pollen. Finally, the abundance, richness, and composition of pollen grains in the frass of Megacyllene caryae varied with collection date (e.g., April 17 vs. April 25, 2016) and location (e.g., forest vs. urban sites). These results provide insight into the natural history and feeding behavior of long-horned beetles, potentially influencing conservation or pest management strategies for forest insects. Moreover, I provide a method to secure evidence of palynivory in insects without having to carry out dissections or field observations.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2019-05-01The student, Xander Hazel, accepted the attached license on 2017-04-26 at 08:48.The student, Xander Hazel, submitted this Thesis for approval on 2017-04-26 at 08:56.This Thesis was approved for publication on 2017-04-27 at 10:47.DSpace SAF Submission Ingestion Package generated from Vireo submission #11057 on 2017-08-10 at 15:07:03Made available in DSpace on 2017-08-10T20:33:25Z (GMT). No. of bitstreams: 2
HAZEL-THESIS-2017.pdf: 1685475 bytes, checksum: 86d7cd37c1f3cba304c9c6d7380ffb7b (MD5)
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Previous issue date: 2017-04-27Embargo set by: Colleen Fallaw for item 102836
Lift date: 2019-08-10T21:27:21Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemU of I Only Restriction Lifted for Item 102836 on 2019-08-11T09:15:17Z
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