169,837 research outputs found
Wastewater treatment and resource recovery for poverty alleviation: a combined duckweed and water hyacinth pond system
No full textFloating macrophyte pond systems, with the ability to produce nutrient
enriched plants simultaneously with wastewater treatment, are a sustainable
solution to contribute to environmental protection and safe nutrient recovery
from domestic wastewater. However, to meet the requirements for reuse with
high strength wastewater containing high levels of metal pollution generated in
developing countries, an adequate combination of water hyacinth and
duckweed ponds is proposed in order to take advantage of the best
characteristics of each of these macrophyte ponds.
This research focused on the advancing of the understanding of the effectiveness
of treatment and resource recovery under the effect of changing operational
parameters such as pH, light intensity, influent metal content and fluctuating
pollutants loading rate on pond performance and recycling ability in order to fill
the noticed gap of knowledge.
Experiments conducted in water hyacinth ponds (WHP), under batch and
tropical natural weather conditions, revealed that pH between 6.4 and 7.1, full
sunlight and seven days hydraulic retention time were optimum for plant
biomass production and pollutant removal in WHP. WHP was able to regulate
pH when the initial pH values moved outside this interval with a drop in
biomass production as a side effect. These ponds showed a first order kinetic for
the removal of iron, zinc and copper from aqueous solution and their
accumulation in plants biomass with a preferential sequence Fe>Zn>Cu.
However the presence of metals in water hyacinth biomass led to the reduction
in ponds performances and a risk of re-pollution of the effluent through the
release of metals into water.
A comparative study carried out over sixty-two weeks in a pilot scale combined
water hyacinth and duckweed ponds (DWP) channel and waste stabilization
ponds channel working under fluctuating loading rates showed different
environmental conditions occurred these ponds. The fluctuating loading rate
was also found to have a reduced effect on the combined WHP/DWP channel
performance and effluent quality stability with the effluents meeting the entire
reuse requirement at high hydraulic flow rate (retention time greater than 20
days). Fish was able to grow in the WHP/DWP channel.
Results suggested some guidelines on WHP/DWP system design, operation and
maintenance. The overall outcome of this research is a significant contribution to
the development of integrated combined WHP/DWP technology for treatment
of wastewater and resource recovery on site
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Evaluation of a risk assessment system for heritage railway earthworks
No full textThere are currently over 100 heritage railways in the UK carrying 6.8 million passengers on 15 million passenger journeys and contributing an estimated £579 million to the UK economy. Many of these lines include significant earthworks, which present a considerable risk to their safe operation. In the last decade there have been major slips at several heritage railways causing major disruption to operations and a serious threat to business continuity.
This research describes the application of a risk assessment system based on that used by Network Rail but specifically adapted for heritage railway conditions. Adaptations include significant alterations to the consequence categories used in prioritization of earthwork issues and a simple low-cost method of implementation based on paper forms and Excel spreadsheets.
Use of the system on two heritage railways, the Bo’ness and Kinneil Railway and the Strathspey Railway is evaluated by means of discussion with railway engineering staff and civil engineering volunteers.
It is concluded that whilst the system represents a realistic and useful approach to management of earthwork assets, the system could not be used by heritage railway volunteer staff without targeted training. Such training, however, would be straightforward to provide, perhaps under the auspices of the Heritage Railway Association
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
No full textWe 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
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
An Article About Albertus C. Van Raalte, Author Unknown, Except for Parts Taken from an Article by Anna C. Post
No full textAn article about Albertus C. Van Raalte, author unknown, except for parts taken from an article by Anna C. Post. The author knew first generation persons in the Holland settlement and therefore, the article has some value.https://digitalcommons.hope.edu/vrp_1890s/1012/thumbnail.jp
Safety and volunteer construction workers
No full textThe construction industry is dangerous, with 39 fatalities at work in the UK in 2012/13 and comparable and even larger figures reported worldwide. People also take part in construction on a voluntary basis; most volunteers have limited training and no technical qualification, whilst safety regulation frameworks range from being comparable to professional sectors to zero regulation in some international contexts. Unstructured interviews were undertaken with volunteer construction workers from two areas: those returning from international development projects and those regularly volunteering on UK heritage railways. Taking a social constructionist perspective, data was explored using discourse analysis to illuminate ‘safety’ within this unique construction ‘industry’. Those with engineering or technical backgrounds developed more tangible constructions of safety, around risks and hazards, within their activities, yet volunteers without this experience also acknowledged a wider context of danger. Volunteers on overseas projects developed discourses of ‘difference’ between safety at home and safety outside the UK, associated with negative practices overseas yet with acceptance of their inevitability as part of the voluntary experience. Further work is proposed to determine whether these insights can contribute to improved safety management within the voluntary construction context
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