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Articles 1471 - 1481 of 1481
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Performance Characteristics Of A Low-Cost, Field-Deployable Miniature Ccd Spectrometer., S. Coles, M. Nimmo, P. J. Worsfold
Performance Characteristics Of A Low-Cost, Field-Deployable Miniature Ccd Spectrometer., S. Coles, M. Nimmo, P. J. Worsfold
School of Geography, Earth and Environmental Sciences
Miniature spectrometers incorporating array detectors are becoming a viable, low-cost option for field and process deployments. The performance characteristics of one such instrument are reported and compared with those of a conventional benchtop instrument. The parameters investigated were wavelength repeatability, photometric linearity, instrumental noise (photometric precision) and instrumental drift.
Optimization Of An Automated Fi-Ft-Ir Procedure For The Determination Of O-Xylene, Toluene And Ethyl Benzene In N-Hexane, Ian Wells, Paul J. Worsfold
Optimization Of An Automated Fi-Ft-Ir Procedure For The Determination Of O-Xylene, Toluene And Ethyl Benzene In N-Hexane, Ian Wells, Paul J. Worsfold
School of Geography, Earth and Environmental Sciences
The development and optimization of an automated flow injection (FI) manifold coupled with a Fourier transform infrared (FT-IR) detector for the determination of toluene, ethyl benzene and o-xylene in an n-hexane matrix is described. FT-IR parameters optimized were resolution and number of co-added scans; FI parameters optimized were type of pump tubing, carrier flow rate and sample volume. ATR and transmission flow cells were compared for the determination of o-xylene, the ATR cell was easier to use and gave better figures of merit, except for sensitivity, for which the transmission cell was twice as good. Multivariate calibration routines were applied …
A Submersible Battery-Powered Flow Injection (Fi) Sensor For The Determination Of Nitrate In Estuarine And Coastal Waters., Anthony R.J. David, Trevor Mccormack, Paul J. Worsfold
A Submersible Battery-Powered Flow Injection (Fi) Sensor For The Determination Of Nitrate In Estuarine And Coastal Waters., Anthony R.J. David, Trevor Mccormack, Paul J. Worsfold
School of Geography, Earth and Environmental Sciences
The design, construction and performance of a remotely deployed submersible flow injection-based nutrient (total oxidized nitrogen) sensor are described. The sensor featured a custom-built microcomputer and a solid-state, flow-through spectrophotometric detector, and the derivatization chemistry was based on in-line copper-cadmium reduction of nitrate to nitrite, and diazotization with N1NED and sulphanilamide. The limit of detection was 0.0014 mg l(-1) NO3-N and the linear range was 0.0014- 0.77 mg l(-1) with a 260 microl sample volume and a 20 mm path length flow cell. Results from submersed deployments in the Tamar estuary and North Sea are also reported.
Energy Demand Perspectives In Bangladesh, (1992/93 – 2019/20), S Rahman
Energy Demand Perspectives In Bangladesh, (1992/93 – 2019/20), S Rahman
School of Geography, Earth and Environmental Sciences
The present paper attempted to forecast the demand for primary energy broadly categorized into: (a) commercial (coal, petroleum, natural gas, and hydropower), and (b) non-commercial energy (rice hull and straw, jute stick, firewoods, crop wastes, etc.) for the period 1992/93-2019/20 AD to facilitate in the energy sector planning and development. The demand forecast, based on past time series data (1972/73-1991/92), is made by utilizing two methods: (a) "Market Penetration Theory" that uses trend extrapolation and inter-fuel substitution priniciples, and (b) "Trend Extrapolation Model" taking into account the the exogenous variables, e.g., GDP and energy/GDP ratio. Results reveal that the fractional …
Technological Change And Women’S Participation In Crop Production In Bangladesh, S Rahman, Jk Routray
Technological Change And Women’S Participation In Crop Production In Bangladesh, S Rahman, Jk Routray
School of Geography, Earth and Environmental Sciences
There is a dearth of information on the employment effects of modern agricultural tech nology on rural women in Bangladesh. The present study1 looks at women's participation in crop production activities, examines their influence in the diffusion of modern technol ogy and their participation in the hired labor market. Data for this study comes from two intensive surveys conducted in the crop years 1989 and 1996 in three agro-ecological regions of Bangladesh. Findings suggest that the prevailing claim-that women are involved only in post- harvest processing of crops-underestimates their contribution to agricultural production. Women's share of total labor is 10-18 …
Rurality, Locality And Industrial Change: A Micro-Scale Investigation Of Manufacturing Growth In The District Of Leominster, Richard Yarwood
Rurality, Locality And Industrial Change: A Micro-Scale Investigation Of Manufacturing Growth In The District Of Leominster, Richard Yarwood
School of Geography, Earth and Environmental Sciences
No abstract provided.
Joint Determination Of Demand For Inputs And Choice Of Rice Varieties In Northern Thailand, S Rahman, S Sriboonchitta
Joint Determination Of Demand For Inputs And Choice Of Rice Varieties In Northern Thailand, S Rahman, S Sriboonchitta
School of Geography, Earth and Environmental Sciences
The paper explores the potential of Khao Dawk Mali expansion in Northern Thailand as well as presents estimation of demand for variable inputs and choice of rice varieties as jointly determined by the profit-maximizing farmers. Results reveal that, Khao Dawk Mali provides economic advantage over glutinous varieties and can be conceived as a better alternative crop particularly in areas with inadequate irrigation and water control facilities. Consideration of the possibility of rice variety switching, that is, allowing the movement along a meta-production function, improved the elasticity estimates. A two-stage switching regression procedure which adjusts for selectivity bias is used to …
A Portable Battery-Powered Flow Injection Monitor For The In Situ Analysis Of Nitrate In Natural Waters., N. J. Blundell, A. Hopkins, P. J. Worsfold, H. Casey
A Portable Battery-Powered Flow Injection Monitor For The In Situ Analysis Of Nitrate In Natural Waters., N. J. Blundell, A. Hopkins, P. J. Worsfold, H. Casey
School of Geography, Earth and Environmental Sciences
The design and performance of a portable, automated flow injection (FI)-based photometric monitor are described. The system is controlled by an in-house microcomputer system that enables the monitor (including a solid state detector) to operate from a 12 V battery supply. The monitor uses the cadmium reduction/diazotization method to analyse for nitrate with a linear range of 0 to 12 mg l(-1) and a limit of detection of 0.05 mg l(-1) (NO(3)-N). The hardware and software design, monitor performance and results obtained during unattended operation are presented.
Automated Cold Vapour Flow-Injection Analysis Of Mercury At High Concentrations., W. T. Corns, L. C. Ebdon, S. J. Hill, P. B. Stockwell
Automated Cold Vapour Flow-Injection Analysis Of Mercury At High Concentrations., W. T. Corns, L. C. Ebdon, S. J. Hill, P. B. Stockwell
School of Geography, Earth and Environmental Sciences
Continuous-flow cold vapour- atomic fluorescence spectrometry is shown to be an extremely sensitive technique for the determination of mercury with detection limits typically below 0.01 mug l(-1). Linear calibration ranges were found to be at least four orders of magnitude (i.e. up to 0.1 mg l(-1)). Samples with concentrations exceeding the linear range are susceptible to self-absorption, and may, in severe cases, cause carry-over problems between samples. The flow-injection approach has been utilized to extend the upper limit of the linear calibration range allowing determinations up to 10 mg l(-1) of mercury. A range of certified reference materials and zinc …
On-Line Analyte Preconcentration With Atomic Spectrometric Detection., L. Ebdon, A. S. Fisher, S. J. Hill, P. J. Worsfold
On-Line Analyte Preconcentration With Atomic Spectrometric Detection., L. Ebdon, A. S. Fisher, S. J. Hill, P. J. Worsfold
School of Geography, Earth and Environmental Sciences
Pre-concentration of analytes, or matrix removal to overcome interferences using mini- or micro-columns of exchange media prior to atomic spectrometric detection is becoming increasingly more common. This paper is a review of some of the more recent applications of chelating, ion exchange and other resins and gels that have been used to accomplish this.
A Simple And Versatile Interface To Feed Analogue Data From The Output Of Analytical Instruments To A Bbc Microcomputer., L. Ebdon, Ji Alonso, S. J. Hill, A. Hopkins
A Simple And Versatile Interface To Feed Analogue Data From The Output Of Analytical Instruments To A Bbc Microcomputer., L. Ebdon, Ji Alonso, S. J. Hill, A. Hopkins
School of Geography, Earth and Environmental Sciences
No abstract provided.