Comparison of a plant based natural surfactant with SDS for washing of As(V) from Fe rich soil

This study explores the possible application of a biodegradable plant based surfactant, obtained from Sapindus mukorossi, for washing low levels of arsenic (As) from an iron (Fe) rich soil. Natural association of As(V) with Fe(III) makes the process difficult. Soapnut solution was compared to anionic surfactant sodium dodecyl sulfate (SDS) in down-flow and a newly introduced suction mode for soil
column washing. It was observed that soapnut attained up to 86% efficiency with respect to SDS in removing As. Full factorial design of experiment revealed a very good fit of data. The suction mode generated up to 83 kPa pressure inside column whilst down-flow mode generated a much higher pressure of 214 kPa, thus making the suction mode more efficient. Micellar solubilisation was found to
be responsible for As desorption from the soil and it followed 1st order kinetics. Desorption rate coefficient of suction mode was found to be in the range of 0.005 to 0.01, much higher than down-flow mode values. Analysis of the FT-IR data suggested that the soapnut solution did not interact chemically with As, offering an option for reusing the surfactant. Soapnut can be considered as a soil washing
agent for removing As even from soil with high Fe content.

Diagnostic accuracy and reproducibility of tendency oriented perimetry in glaucoma

PURPOSE. To evaluate the diagnostic capability of tendency oriented perimetry (TOP) in glaucoma. METHODS. A): The diagnostic accuracy of mean defect (MD), square-root of the loss variance (sLV), and number of pathologic points (NPP) was calculated in 295 normal and 414 glaucoma eyes (179 early, 112 moderate, and 123 advanced) examined with TOP. B): Threshold fluctuation (F) and its relationship with the loss variance (LV) was measured in 34 normal and 33 glaucoma eyes (mean MD=3 dB; SD=3.9) for TOP and for full-threshold perimetry (FT). C): Twenty-eight eyes with stable glaucoma (mean MD=9.5 dB; SD=7.2) were examined six times to quantify LV error. D): TOP and FT were tested with the simulation program PeriSim using different behavior models. RESULTS. A): The best diagnostic index in early glaucoma (MD

A SiGe Power Amplifier with Integrated BALUNs for 81-86 GHz E-Band Backhaul Applications

The design of a two-stage differential cascode power amplifier (PA) for 81-86 GHz E-band applications is presented. The PA was realised in SiGe technology with fT/fmax 170/250 GHz. A broadband transformer with efficiency higher than 79.4% from 71 GHz to 96 GHz is used as a BALUN. The PA delivers a 4.5 dBm saturated output power and exhibits a 13.4 dB gain at 83.6 GHz. The input and output return losses agree well with the design specifications.

A Compact V-band power detector

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A compact V-band active power detector using Infineon 0.35 µm SiGe HBT process (fT/fmax =170/250 GHz) is described. The total chip area is only 0.35×0.8 mm2 including all pads. This design exhibits a dynamic range larger than 20 dB over the frequency range from 55 GHz to 67 GHz. It also offers a simple and low-power application potential as an envelop detector in multi-Gbps high data rate demodulators for OOK/ASK etc.

Impaired lung function and Health Status in Adult Survivors of Bronchopulmonary Dysplasia

More infants with bronchopulmonary dysplasia (BPD) now survive to adulthood but little is known regarding persisting respiratory impairment. We report respiratory symptoms, lung function and health-related quality of life (HRQoL) in adult BPD survivors compared with preterm (non-BPD) and full term (FT) controls.

Respiratory symptoms (European Community Respiratory Health Survey) and HRQoL [EuroQol 5D (EQ-5D)] were measured in 72 adult BPD survivors [mean(SD) study age 24.1(4.0)y; mean(SD) gestational age (GA)=27.1(2.1)wk; mean(SD) birth weight (BW)=955(256)g] cared for in the Regional Neonatal Intensive Care Unit, Belfast (between 1978 and 1993) were compared with 57 non-BPD controls [mean(SD) study age 25.3(4.0)y; mean(SD) GA 31.0(2.5)wk; mean(SD) BW 1238(222)g] and 78 FT controls [mean(SD) study age 25.7(3.8)y; mean(SD) GA=39.7(1.4)wk; mean(SD) BW=3514(456)g] cared for at the same hospital. Spirometry was performed on 56 BPD, 40 non-BPD and 55 FT participants.

BPD subjects were twice as likely to report wheeze and three times more likely to use asthma medication than controls. BPD adults had significantly lower FEV1 and FEF25–75 than both the preterm non-BPD and FT controls (all p<0.01). Mean EQ-5D was 6 points lower in BPD adults compared to FT controls (p<0.05).

BPD survivors have significant respiratory and quality of life impairment persisting into adulthood.

‘CLAM’ tests for measuring in-situ permeation properties of concrete

This paper descirbes a simple test measuring the sorptivity (a measure of the absorption property if concrete) and the air and water permeability of concrete on site. Using this test, the decay of pressure is monitired for the air permeability test.whereas water penetrating into the concrete at a constant pressure of 0.01 bar and 1.5 bar are recorded for the sorptivity and the water permeability tests respectively. These tests are essentially non-destructive in nature and a skilled operator is not needed. It is possible to carry out a number of tests quickly and efficiently on site without prior planning. It has been found that statistically satisfactory results can be obtained from a mean of three tests. As the flow lines are largely concentrated within 40 mm from the surface, reasonably reliable results can be obtained by drying the surface even if the surface under test is initially wet.

Forensic analysis of architectural finishes using fourier transform infrared and raman spectroscopy, part II:White paint

White household paints are commonly encountered as evidence in the forensic laboratory but they often cannot be readily distinguished by color alone so Fourier transform infrared (FT-IR) microscopy is used since it can sometimes discriminate between paints prepared with different organic resins. Here we report the first comparative study of FT-IR and Raman spectroscopy for forensic analysis of white paint. Both techniques allowed the 51 white paint samples in the study to be classified by inspection as either belonging to distinct groups or as unique samples. FT-IR gave five groups and four unique samples; Raman gave seven groups and six unique samples. The basis for this discrimination was the type of resin and/ or inorganic pigments/extenders present. Although this allowed approximately half of the white paints to be distinguished by inspection, the other half were all based on a similar resin and did not contain the distinctive modifiers/pigments and extenders that allowed the other samples to be identified. The experimental uncertainty in the relative band intensities measured using FT-IR was similar to the variation within this large group, so no further discrimination was possible. However, the variation in the Raman spectra was larger than the uncertainty, which allowed the large group to be divided into three subgroups and four distinct spectra, based on relative band intensities. The combination of increased discrimination and higher sample throughput means that the Raman method is superior to FT-IR for samples of this type. © 2005 Society for Applied Spectroscopy.

In-situ Monitoring of Solid Oxide Electrolysis Cells

High temperature co-electrolysis of steam and carbon dioxide using a solid oxide cell (SOC) has been shown to be an efficient route to produce syngas (CO + H-2), which can then be converted to synthetic fuel. Optimization of co-electrolysis requires detailed understanding of the complex reactions, transport processes and degradation mechanisms occurring in the SOC during operation. Thermal imaging, Raman spectroscopy and Diffuse Reflectance Infrared Fourier Transform Spectroscopy are being developed to probe in-situ both the reactions occurring during operation and any associated changes within the structure of the electrodes and electrolyte. Here we discuss the challenges in designing experimental apparatus suitable for high temperature operation with optical spectroscopic access to the areas of the SOC that are of interest. In particular, issues with sealing, temperature gradients, signal strength and cell configuration are discussed and final designs are presented. Preliminary results obtained during co-electrolysis operation are also presented.

Microstructural analysis of non-woven fabrics using scanning electron microscopy and image processing. Part 1:Development and verification of the methods

This paper reports image analysis methods that have been developed to study the microstructural changes of non-wovens made by the hydroentanglement process. The validity of the image processing techniques has been ascertained by applying them to test images with known properties. The parameters in preprocessing of the scanning electron microscope (SEM) images used in image processing have been tested and optimized. The fibre orientation distribution is estimated using fast Fourier transform (FFT) and Hough transform (HT) methods. The results obtained using these two methods are in good agreement. The HT method is more demanding in computational time compared with the Fourier transform (FT) method. However, the advantage of the HT method is that the actual orientation of the lines can be concluded directly from the result of the transform without the need for any further computation. The distribution of the length of the straight fibre segments of the fabrics is evaluated by the HT method. The effect of curl of the fibres on the result of this evaluation is shown.

Application of colloidal gas aphron suspensions produced from Sapindus mukorossi for arsenic removal from contaminated soil

Colloidal gas aphron dispersions (CGAs) can be described as a system of microbubbles suspended homogenously in a liquid matrix. This work examines the performance of CGAs in comparison to surfactant solutions for washing low levels of arsenic from an iron rich soil. Sodium Dodecyl Sulfate (SDS) and saponin, a biodegradable surfactant, obtained from Sapindus mukorossi or soapnut fruit were used for generating CGAs and solutions for soil washing. Column washing experiments were performed in down-flow and up flow modes at a soil pH of 5 and 6 using varying concentration of SDS and soapnut solutions as well as CGAs. Soapnut CGAs removed more than 70% arsenic while SDS CGAs removed up to 55% arsenic from the soil columns in the soil pH range of 5–6. CGAs and solutions showed comparable performances in all the cases. CGAs were more economical since it contains 35% of air by volume, thereby requiring less surfactant. Micellar solubilization and low pH of soapnut facilitated arsenic desorption from soil column. FT-IR analysis of effluent suggested that soapnut solution did not interact chemically with arsenic thereby facilitating the recovery of soapnut solution by precipitating the arsenic. Damage to soil was minimal arsenic confirmed by metal dissolution from soil surface and SEM micrograph.

Inhibitory Effect of Phosphonium-Based Ionic Liquids on Coal Oxidation

To develop a chemical inhibitor that can efficiently suppress coal oxidation, nine tetraalkylphosphonium-based ionic liquids (ILs) and one imidazolium-based IL [1-allyl-3-methylimidazolium chloride ([AMIm]Cl)] were examined as additives. These ILs were used to treat and investigate the inhibitory effect on the oxidation activity and the structure of lignite coal. Characterization using thermogravimetric analysis showed that phosphonium-based ILs are able to inhibit coal oxidation up to 400 degrees C with the tributylethylphosphonium diethylphosphate ([P-4,P-4,P-4,P-2][DEP]) found to be the most effective. In contrast to the tetraalkylphosphonium-based ILs, inhibition using [AMIm]Cl was only found to be effective at temperatures below 250 degrees C, indicating that the tetraallcylphosphonium-based ILs may be more suitable for the future application of suppressing coal spontaneous combustion over a wide range of temperatures. Fourier transform infrared spectroscopic data showed that the various functional groups change in the coal following IL treatment, which are a decrease in the minerals and hydrogen bonds in all treated coals, while decreased aliphatic hydrocarbon and increased carbonyl bonds only appeared in some samples. During the oxidation of coal, the decomposition of aliphatic hydrocarbon groups is inhibited and the formation of carbonyl groups is delayed, so that the evolved gas concentration decreased, as shown by the temperature-programmed oxidation-mass spectrometry results. The deployment of the [P-4,P-4,P-4,P-2][ DEP] and tributylmethylphosphonium methylsulfate Its as additives also show good inhibitory effect on coal oxidation over the temperature range studied, and a relatively stronger interaction between [P-4,P-4,P-4,P-2] [DEP] and coal is demonstrated by the additive model.

Progressive deformation of glacial till due to viscoplastic straining and pore pressure variation

The stress regime in a cutting (slope) is complex, with different principle stresses acting in different directions along the potential failure plane. For example, stresses may be primarily in extension near the toe and in compression near the crest of a slope. Cuttings in heavily overconsolidated clays are known to be susceptible to progressive failure which usually starts at the toe of the slope. Softening and the development of rupture surfaces have been observed in the field and are well documented for London Clays. However, this failure mechanism is yet to be established for glacial tills. To better understand the progressive failure mechanism, this paper discusses a series of laboratory tests conducted on reconstituted glacial till samples from Northern Ireland. Initial observations indicate that, a soil with insitu stress states between 80-90% of peak strength may undergo significant viscoplastic straining as a result of the combination of pore-pressure cycling and elevated stress level.