Design of a wide-bandwidth on-chip antenna for uncooled passive THz imaging

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Effect of centrifuge conditions on water and total dissolved phosphorus extraction from soil

Centrifugation of soils to extract soil water is widely used to investigate the chemical properties of soil water. However, no single set of standard operating conditions in terms of centrifuge time and speed have been defined. This study investigated centrifuge conditions on the effect of volume of soil water and phosphorus concentrations extracted to determine a set of standard operating conditions that could be used for soil water extraction in the future. Two contrasting soils that had been dried and rewet, a Ferrosol and a Dermosol, were used to investigate centrifuge speed (1000-3000 r.p.m.) and centrifuge time (5-30 min) on the extraction of soil water. Centrifuge speeds of 1000, 2000, and 3000 r.p.m. were trialed in this study giving relative centrifugal forces of 220, 881, and 1982g respectively. Increasing centrifuge time significantly increased (P < 0.001) the volume of soil water extracted. Almost twice as much soil water was extracted when the centrifuge time was increased from 5 to 30 min. Centrifuge speed was also a highly significant factor (P < 0.001) in increasing the volume of soil water extracted. The amount of soil water extracted increased by up to 15% when the centrifuge speed was increased from 1000 to 3000 r.p.m. The concentration of total dissolved phosphorus (TDP) did not change significantly with either centrifuge speed or time. The most important factor in determining the concentration of TDP was the soil type. The conditions that gave an adequate volume of soil water for analyses from field-moist soils in the shortest amount of time were a centrifuge force of 1982g and a time of 10 min

Headspace gas chromatography with flame ionization detection (HS-GC-FID) for the determination of dissolved methane in wastewater

There is currently a need for a simple, accurate and reproducible method that quantifies the amount of dissolved methane in wastewater in order to realize the potential methane that can be recovered and account for any emissions. This paper presents such a method, using gas chromatography with flame ionization detection fitted with a GS-Gas PRO column coupled with a headspace auto sampler. A practical limit of detection for methane of 0.9 mg L-1, with a retention time of 1.24 min, was obtained. It was found that the reproducibility and accuracy of the method increased significantly when samples were collected using an in-house constructed bailer sampling device and with the addition of 100 μL hydrochloric acid (HCl) and 25% sodium chloride (NaCl) and sonication for 30 min prior to analysis. Analysis of wastewater samples and wastewater sludge collected from a treatment facility were observed to range from 12.51 to 15.79 mg L-1(relative standard deviation (RSD) 8.1%) and 17.56 to 18.67 mg L-1(RSD 3.4%) respectively. The performance of this method was validated by repeatedly measuring a mid-level standard (n = 8; 10 mg L-1), with an observed RSD of 4.6%.</p

Phosphorus between soil, soil water and overland flow for established and laser graded, border-check irrigation systems

Agricultural systems contribute to excessive phosphorus (P) additions that are adversely affecting water resources worldwide. The effects of soil disturbance on P exports have not been widely reviewed. In February 2004, four established and four recently laser graded (&lt;4 yrs) border-check irrigation bays on the Macalister Research Farm (38°00&#039;S 146°54&#039;E) were sampled during and after irrigation. Samples were taken at the channel inlet and every 60 m thereafter. Overland flow was sampled at the wetting front and back up the bays, and soil samples were recovered from the sampling locations two days after irrigation. Overland flow was analysed for total P (TP), the soil samples were analysed for soil Olsen P (0-20 and 0-100 mm depths) and soil water, dissolved reactive P (SWDRP) and total P (SWTP) (0-20 mm depth)

Changes in nitrogen and phosphorus concentrations in soil, soil water and surface run-off following grading of irrigation bays used for intensive grazing

Soil tests are often used to identify areas at risk of excessive phosphorus (P) exports. We investigated the changes in soil P (0-20 mm) in four recently laser-graded (&lt;1 year) and four established (&gt;10 years) irrigated pastures in south-eastern Australia before and after 3 years of irrigated dairy production. At the second sampling, soil water P and nitrogen (N), and P and N in surface run-off (overland flow) were also measured enabling comparison of P in surface run-off with measures of soil P. In surface soil (0-20 mm), grading reduced measures of soil P, while P sorption increased. Over 3 years, in the graded bays, Olsen P, Colwell P and P sorption decreased and water extractable P and P sorption saturation increased, while Olsen P and Colwell P decreased in the established bays. After 3 years, total dissolved P (TDP) concentrations in soil water were greater in the established bays, but dissolved reactive P (DRP) concentrations were unaffected. Organic P in soil water comprised 70 and 32% of TDP in the established and graded bays, respectively. The soil water analyses were reflected in surface run-off. After 3 years, laser grading decreased TDP, TDN, TP and TN exports in wetting front run-off by 40, 29, 41 and 36%, respectively, compared with established bays. This is an important result for the management of dairy systems as it suggests that the regular cultivation used to renovate pasture on more intensive dairy farms decreases the exports of P and N

A Radiation Tolerant Gigabit Serializer for LHC Data Transmission

In the future LHC experiments, some data acquisition and trigger links will be based on Gbit/s optical fiber networks. In this paper, a configurable radiation tolerant Gbit/s serializer (GOL) is presented that addresses the high-energy physics experiments requirements. The device can operate in four different modes that are a combination of two transmission protocols and two data rates (0.8 Gbit/s and 1.6 Gbit/s). The ASIC may be used as the transmitter in optical links that, otherwise, use only commercial components. The data encoding schemes supported are the CIMT (G-Link) and the 8B/10B (Gbit-Ethernet &amp; Fiber Channel). To guarantee robustness against total dose irradiation effects over the lifetime of the experiments, the IC was fabricated in a standard 0.25 µm CMOS technology employing radiation tolerant layout practices. The device was exposed to different irradiation sources to test its sensitivity to total dose effects and to single effects upsets. For this tests, a comparison is established with a commercial serializer. I

A 90GS/s 8b 667mW 64x Interleaved SAR ADC in 32nm Digital SOI CMOS

A 90GS/s 8b low-power ADC is presented achieving 33.0-36.0dB SNDR and a FoM of 203fJ/conversion-step. High conversion speed of up to 100GS/s and high input bandwidth of 22GHz is achieved by using a 1:64 interleaver with integrated sampling. Single NMOS transistors followed by 1:4 demux stages are used to sample the signal. Skew and gain adjustment is implemented on-chip. The ADC consumes 667mW at 90GS/s and 845mW at 100GS/s and can be operated from a single supply voltage. It is implemented in 32nm SOI CMOS and occupies 0.45mm2