Conventional Strip Research Articles

Detection of Human Chorionic Gonadotropin (hCG) Hormone using Digital Lateral Flow Immunoassay.

The main goal of this work was to establish a hybrid device incorporating an electrochemical-based transducer on a conventional lateral flow assay strip in order to perform an on-chip fast testing method for the detection of various bio-analyses. In this context, the expected development of the digital lateral-flow immunoassay to be considered a reliable low-cost instrument improves the future of the very simple and flexible approach oflateral-flow assays. It is anticipated to achieve a digital quantitative lateral-flow immunoassay by exploring the electrochemical transducers alongwith recognition elements for digitization of commercially available rapid tests. As a preliminary step, the described technique will be validated using two standard electrochemical measurements (amperometric and impedimetric) across two electrodes fixed onto the surface of LFA strip. The LFA strips were prepared at the factory for pregnancy tests and modified by adding two parallel copper electrodes at the lab. These strips were proven by in-vitro experiments to be reusable lasting for 20-30 multiple days. Further on, the detection of hCG Ab-Ag interaction using these strips was performed. Two different types of measurements, namely amperometric and impedimetric, were used which yielded similar results to those reported in literature with screen-printed micro-electrodes. In addition, different concentrations of NaCl and hCG Ag solution were investigated. However, the expected linear concentration response was obtained. A promising proof-of-concept have been achieved through this study. Further studies are needed to complete the development of fully printed disposable electrochemical devices that are able to either display a digital result directly or transmit data to a mobile phone using RFID/NFC.

Study of processing, microstructure and mechanical properties of hot rolled ultra-high strength steel

ABSTRACTHot rolled ultra-high strength steel with a gauge range of 3–10 mm (0.118¨–0.395¨) was developed using conventional slab caster and hot strip mill technology at Stelco Inc. (Stelco) to meet standard industry specifications along with additional unique customer requirements. The effects of chemical composition, steelmaking and hot rolling process parameters on microstructure, precipitation behaviour, and mechanical properties were studied. Both Grade 90 (620 Mpa, Stelco trademarked STELMAXTM90) and Grade 100 (690 MPa, STELMAXTM100) products met strength requirements in longitudinal and transverse directions. Furthermore, these ultra-high strength steels exhibited excellent ductility, impact toughness, edge stretchability and bendability. The enhanced mechanical properties are the results of chemistry design and carefully controlling austenite/ferrite grain size and precipitation behaviour at different processing stages. These newly developed steels have extensive applications in automobile safety components, light-weight construction, piping/tubing and offshore structures.

Highly sensitive detection of high-risk bacterial pathogens using SERS-based lateral flow assay strips

Bacterial pathogens such as Yersinia pestis, Francisella tularensis, and Bacillus anthracis are classified into the highest rank of potential bioterrorism agents. Colorimetric lateral flow assay (LFA) strips are commercially available but these conventional strips have drawbacks in terms of low sensitivity and limit of quantitative analysis. Therefore, there is an urgent need for a new sensing platform to detect these pathogens in the early contamination stage. In this study, a novel surface-enhanced Raman scattering (SERS)-based LFA strip was developed for sensitive detection of bacterial pathogens. Target-specific SERS nanotags (Raman reporter-labeled gold nanoparticles) were used as an alternative to the gold nanoparticles in conventional LFA strips. Using these SERS nanotags the presence of bacteria could be identified through a simple color change in the test line. Additionally, highly sensitive and accurate quantitative analysis could be performed by monitoring the characteristic Raman peak intensity of SERS nanotags that were captured in the test line. This highly sensitive method required a short assay time (15 min) and a tiny volume of pathogen sample (40 μL). We believe that the proposed SERS-based LFA technique has great potential as a valuable tool in the early detection of specific bacterial pathogens in the field due to its excellent analytical sensitivity.

Reclamation of copper from spent ammoniacal Printed Circuit Board (PCB) etch solutions

Ammoniacal spent etch liquors is a potential source for copper recovery. In the present investigation copper was extracted from spent ammoniacal PCB etch solutions using hydroxyoxime LIX 84I. Maximum extraction was observed at equilibrium pH of 8.9. Three counter-current stages were required for quantitative extraction of 51.8 g/L copper from the spent liquor using 50%v/v extractant at an O/A ratio of 1.5. It was also possible to achieve quantitative extraction with 20% v/v extractant concentration at an equilibrium pH of 8.9 and O/A ratio 4.5:1. Precipitation −stripping of the loaded organic phase using oxalic acid led to reclamation of copper as copper oxalate. Contacting the oil phase fully loaded with copper in 50% v/v extractant, with 1 M oxalic acid at equal O/A resulted in 77.4% copper getting stripped in first contact, quantitative stripping was achieved in the second contact with fresh acid. There was a close agreement between the experimental and predicted yields based on solubility plots developed for copper-oxalic acid system. Co-extracted ammonia to the organic phase was stripped as soluble ammonium oxalate offering an inherent advantage over the conventional stripping process where build-up of ammonium sulphate is observed during electrowinning process. Calcinations for three hours formed copper oxide, XRD and chemical analysis confirmed the formation of pure copper oxide. The copper present in waste etchant could thus be appropriately converted to value added product.

Tunable Plasmonic Nanolaser Based on Graphene

Surface plasmon polariton nanolaser, which can achieve all-optical circuits and optoelectronic integration, is a major research area in nano-optics. We propose a novel tunable nanolaser that combines graphene and traditional metal–dielectric waveguide. We can tune the gain threshold and ejection frequency according to changes in the electronic characteristics of graphene and the structural parameters of the nanolaser. When the Fermi energy level is 0.8 eV, the Q-factor can reach 85, thereby indicating the outstanding performance of the nanolaser in manufacturing. We also found that the gain threshold will stop increasing when carrier mobility is increased to 2000 푐푚2/V∙s. Compared with the conventional silver strip structure, the proposed nanolaser exhibits better performance at h_gap = 0 nm. On that condition, the optimal values of propagation loss and the normalized mode area are 0.13 and 0.0001 dB/μm, respectively. The proposed nanolaser can overcome the challenges of high speed, miniaturization, and integration in optoelectronic integrated technology.

Three-year follow-up and quality of life of endovenous radiofrequency ablation of the great saphenous vein with the ClosureFast™ procedure: Influence of BMI and CEAP class.

Purpose Endovascular ablation of the great saphenous vein has been proposed as a less invasive alternative to conventional ligation and stripping of varicose veins. Outcomes of patients treated with the radiofrequency ablation ClosureFast™ system over an eight-year period from a single-center were evaluated. Methods Three-year follow-up data included duplex ultrasound scan, complication rate, and questionnaires to assess patients' QOL, level of pain, and days off work. Results A total of 1080 consecutive patients (49.5 ± 18.6 years, 72% female, mean body mass index: 25.44 ± 4.1 kg m-2) underwent radiofrequency ablation for incompetent saphenous veins in a single institution. Occlusion of the great saphenous vein was obtained in 98.6% and 93.8% cases at the end of the procedures and within 36 months, respectively. Only three deep venous thromboses and minor complications occurred in this series throughout the first week from the procedure. A decrease of the external vein diameter, equal to 72.7% and 31.1% of the pretreatment diameter, was observed at 1 week and 36 months, respectively. The average Aberdeen Varicose Vein Questionnaire score improved from 18.06 ± 9.47 before treatment to 11.56 ± 10.23 at 12 months, with no significant differences in the subsequent follow-up. SF-36 QOL scores significantly improved after the procedure in all domains, while there were no changes over time. Patients reported a prompt return to normal daily activities (1.5 ± 0.7 days) and work (3.1 ± 1.9 days). Body mass index influenced QOL scores, while it did not affect great saphenous vein diameter reduction during the follow-up. On the contrary, Clinical Etiologic Anatomic Pathophysiologic class significantly influenced both great saphenous vein diameter reduction after the treatment and QOL scores within 36 months. Conclusion Results of this retrospective monocentric, large patients study suggest that radiofrequency ablation of the great saphenous vein may be a safe and efficient alternative to conventional surgery.

Energy Saving and Process Optimization in a Conventional Hot Strip Mill by Application of the Latest High-efficient Descaling Technology

The paper describes the conversion to a new generation of descaling nozzles in a conventional hot strip mill for steel. There are descaling stations behind the reheating furnace, on the roughing mill stands, and in front of the finishing mill. Before the converting, three high pressure pumps had been in operation to supply the descaling stations. The new descaling nozzles were tested first in the finishing mill descaler with good results. There were considerable water savings without compromising the descaling effect and the material surface quality. After a successful test, the remaining descaling stations were converted accordingly. The overall water saving was approx. 20%, which allowed shutting off one of the three high-pressure pumps. The electrical energy saving amounts to 30,000 kWh/day or about 9,300,000 kWh/year. At the current energy costs, this is equivalent to about 642,000 €. Additional advantages are also seen, such as reduced material cooling and the lower wear of the components of the whole high-pressure water hydraulic system.

Cut of OPEX—Sophisticated Technical Solutions for Hot Strip Mills

The yield and economy during hot strip rolling depend on developing high capacity components fulfilling further the increasing customers’ demands for cost and resource effective production figures. The paper gives an overview of the latest developments for high capacity components and tools of the SMS group for conventional hot strip mills and CSP® plants. The SMS components cover the fields’ mill mechanics, electric, and automation as well as mill reliability and customer strip quality figures in case of modernization tasks as well as erection of new mills.

Electrochemical Stripping to Recover Nitrogen from Source-Separated Urine.

Recovering nitrogen from separately collected urine can potentially reduce costs and energy of wastewater nitrogen removal and fertilizer production. Through benchtop experiments, we demonstrate the recovery of nitrogen from urine as ammonium sulfate using electrochemical stripping, a combination of electrodialysis and membrane stripping. Nitrogen was selectively recovered with 93% efficiency in batch experiments with real urine and required 30.6 MJ kg N-1 in continuous-flow experiments (slightly less than conventional ammonia stripping). The effects of solution chemistry on nitrogen flux, electrolytic reactions, and reactions with electro-generated oxidants were evaluated using synthetic urine solutions. Fates of urine-relevant trace organic contaminants, including electrochemical oxidation and reaction with electro-generated chlorine, were investigated with a suite of common pharmaceuticals. Trace organics (<0.1 μg L-1) and elements (<30 μg L-1) were not detected at appreciable levels in the ammonium sulfate fertilizer product. This novel approach holds promise for selective recovery of nitrogen from concentrated liquid waste streams such as source-separated urine.

The "Tracked Roaming Transect" and distance sampling methods increase the efficiency of underwater visual censuses.

Underwater visual census (UVC) is the most common approach for estimating diversity, abundance and size of reef fishes in shallow and clear waters. Abundance estimation through UVC is particularly problematic in species occurring at low densities and/or highly aggregated because of their high variability at both spatial and temporal scales. The statistical power of experiments involving UVC techniques may be increased by augmenting the number of replicates or the area surveyed. In this work we present and test the efficiency of an UVC method based on diver towed GPS, the Tracked Roaming Transect (TRT), designed to maximize transect length (and thus the surveyed area) with respect to diving time invested in monitoring, as compared to Conventional Strip Transects (CST). Additionally, we analyze the effect of increasing transect width and length on the precision of density estimates by comparing TRT vs. CST methods using different fixed widths of 6 and 20 m (FW3 and FW10, respectively) and the Distance Sampling (DS) method, in which perpendicular distance of each fish or group of fishes to the transect line is estimated by divers up to 20 m from the transect line. The TRT was 74% more time and cost efficient than the CST (all transect widths considered together) and, for a given time, the use of TRT and/or increasing the transect width increased the precision of density estimates. In addition, since with the DS method distances of fishes to the transect line have to be estimated, and not measured directly as in terrestrial environments, errors in estimations of perpendicular distances can seriously affect DS density estimations. To assess the occurrence of distance estimation errors and their dependence on the observer’s experience, a field experiment using wooden fish models was performed. We tested the precision and accuracy of density estimators based on fixed widths and the DS method. The accuracy of the estimates was measured comparing the actual total abundance with those estimated by divers using FW3, FW10, and DS estimators. Density estimates differed by 13% (range 0.1–31%) from the actual values (average = 13.09%; median = 14.16%). Based on our results we encourage the use of the Tracked Roaming Transect with Distance Sampling (TRT+DS) method for improving density estimates of species occurring at low densities and/or highly aggregated, as well as for exploratory rapid-assessment surveys in which divers could gather spatial ecological and ecosystem information on large areas during UVC.

Interference Analysis for Electrochemical Heavy Metal Ion Sensors in Terms of Stripping Current, Barrier Width and Adsorption

Understanding interference effects toward the detection of target analytes is important. In an earlier work we reported for the first time the use of the barrier width (BW) technique using a single concentration of the target analyte (Cd2+) to characterize the interference effects of various heavy metal ions with lesser number of experiments as compared to the conventional stripping current based peak reduction (PR) technique, and developed a scale of interference. There is a need to benchmark the BW technique with the PR technique for its claim of usage and to develop a scale of interference with a higher resolution. In this work, utilizing the BW technique we report the analysis based on Cd2+ concentrations spanning two orders of magnitude and interfering ions (Al3+ (less interfering), Fe2+ (moderately interfering) and Cr6+ (heavily interfering)) also spanning two orders of magnitude. The sensitivity parameters were benchmarked thereby validating BW technique. Adsorption isotherms were constructed for each case and −ΔGads values were evaluated. A correlation obtained from the sensitivity parameters from the BW and PR techniques and −ΔGads yielded an interference scale with a resolution higher than that of the scale obtained by the PR technique or the BW technique.

Separation of nitrous oxide from aqueous solutions applying a micro porous hollow fiber membrane contactor for energy recovery

Abstract Nitrous oxide (N 2 O) is a potent green-house gas, but has also recently been acknowledged as sustainable energy source that can intentionally be produced by bioreactor systems such as the C oupled A erobic-anoxic N itrous D ecomposition O peration (CANDO). In this study, the application potential of a porous hollow fiber membrane contactor has been assessed at expected conditions of an operating CANDO system in shell-side liquid feed operation for N 2 O removal. At varying feed concentrations, liquid and gas flow rates, off-gas concentrations, removal efficiencies, trans-membrane fluxes and mass-flows have been assessed and compared to previous studies on CO 2 . Under the applied operational conditions, the gas flow rate had no significant effect on the results. Removal efficiencies up to 77% of the module feed load demonstrated a high application potential for the CANDO process and indicate a promising removal potential greater 90% in reference to typical initial substrate loads in an operating CANDO system. Additionally, considerably higher off-gas concentrations compared to recently published results applying conventional stripping technology of 3700 ppmv were generated reducing sweeping gas demand by 70%. The mass transfer was dominated by the superficial velocity on the liquid side and its behavior could be well described by Sherwood correlations. However, previously published mass transfer correlations over-estimated the results. Hence, a more appropriate correlation is presented to describe the observations of this study.

Paper-Plastic Hybrid Microfluidic Device for Smartphone-Based Colorimetric Analysis of Urine.

In this work, a disposable paper-plastic hybrid microfluidic lab-on-a-chip (LOC) has been developed and successfully applied for the colorimetric measurement of urine by the smartphone-based optical platform using a "UrineAnalysis" Android app. The developed device was cost-effectively implemented as a stand-alone hybrid LOC by incorporating the paper-based conventional reagent test strip inside the plastic-based LOC microchannel. The LOC device quantitatively investigated the small volume (40 μL) of urine analytes for the colorimetric reaction of glucose, protein, pH, and red blood cell (RBC) in integration with the finger-actuating micropump. On the basis of our experiments, the conventional urine strip showed large deviation as the reaction time goes by, because dipping the strip sensor in a bottle of urine could not control the reaction volume. By integrating the strip sensor in the LOC device for urine analysis, our device significantly improves the time-dependent inconstancy of the conventional dipstick-based urine strip, and the smartphone app used for image analysis enhances the visual assessment of the test strip, which is a major user concern for the colorimetric analysis in point-of-care (POC) applications. As a result, the user-friendly LOC, which is successfully implemented in a disposable format with the smartphone-based optical platform, may be applicable as an effective tool for rapid and qualitative POC urinalysis.

Improving body fluid identification in forensic trace evidence-construction of an immunochromatographic test array to rapidly detect up to five body fluids simultaneously.

Body fluid identification is a substantial part of forensic trace analyses. The correct determination of the origin of a biological stain may give valuable information regarding the circumstances of a crime. A simple way to detect a body fluid in a stain is the use of immunochromatographic strip tests. They are easy to use, user-independent, quick, and cheap. Currently, however, it is only possible to analyze one body fluid at a time, requiring the analyst to make previous, possibly subjective, assumptions on the body fluid at hand. Also, identification of mixed body fluids requires the use of several tests, which results in additional sample and time consumption. To combine a simple approach with the possibility to simultaneously detect several body fluids, we constructed a combined immunochromatographic strip test array based on commercially available tests. The array rapidly detects up to five body fluids with a single analysis, and allowing for subsequent DNA extraction from the same material. With this test it was possible to identify the components of a mixture, the test was easily incorporated into standard laboratory work, and its sensitivity and specificity were shown to be comparable to those of conventional strip tests.

Stability evaluation method for hyperbolic coal pillars under the coupling effects of high temperature and ground stress

We studied an underground coal gasification technique using strip mining-face mining gasifier controlled retraction injection technology (SMFM). This green mining approach offers several advantages over conventional strip mining but the stress distribution and stability of SMFM operations remain largely untested. In particular, hyperbolic coking pillars are used in SMFM compared with rectangular pillars used in traditional strip mining, which can influence the ultimate bearing capacity and stability. We use numerical simulations to investigate the influence of different factors (arch height, pillar height and width, mechanical characteristics), under the coupling effect of high temperature, on the ultimate bearing capacity of hyperbolic pillars. Our results indicate that arch height has a strong influence on pillar stress, while changes in pillar width and height are less significant. A stability evaluation method is proposed and tested on a case study in Inner Mongolia. Our theoretical results have practical significance for the promotion and application of SMFM.

Flow and self-noise around bypass transition strips

To analyze the downstream effects of bypass transition strips on a laminar incoming flow, a direct numerical simulation of the fully transient, explicit and compressible Lattice Boltzmann equations is performed. Near wake analysis of a staggered grid of cubic blocks as transition device is compared with a more conventional zigzag strip, to ensure transition to a fully developed conical boundary layer. The staggered grid of blocks is more efficient in stopping the flow and creating large, coherent, flow structures of the size of the blocks, which results in a stronger transition. However, the downstream merging of spanwise created structures is relatively long resulting in higher correlated boundary layers. If the spanwise variation of the zigzag strip is small, the streamwise vortices created merge quicker, resulting in an earlier uncorrelated boundary layer. The self-noise created by zigzag strip is also significantly less than the noise from the staggered grid of blocks and becomes only dominant at high frequency compared to the predicted trailing edge noise.

Thermally Activated Gas-Phase Chemical Reactions in a Single-Wafer Wet Clean Process

A conventional high-dose ion-implanted photoresist strip and clean process flow consists of using a dry remote plasma ashing tool to remove the crust layer and underlying photoresist formed during the implant, followed by sulfuric-peroxide mixture (SPM) and ammonium hydroxide-hydrogen peroxide (SC1) chemistries applied on a wet clean tool to remove the remaining bulk photoresist and implant residues. However, film loss control and residue removal are increasingly difficult to maintain for sub-10 nm devices with conventional approaches. We investigate an alternative sequence that replaces the remote plasma strip with a thermally activated, atmospheric gas-phase oxidation process and replaces the SPM chemistry with a de-ionized water/ozone (DIO3) wet clean. The alternative sequence is entirely processed in a modified single-wafer wet clean chamber. For the oxidation process, a dry O3/O2 gas mixture decomposes and reacts directly with the ion-implanted photoresist wafer that is heated above 300°C from the backside. 9,000 Å/min strip rates are measured on 193 nm photoresist, and 650 Å/min are measured for the implanted crust removal. Based on both X-ray photoelectron spectroscopy (XPS) analysis of the reacted surface as well as the composition of the gas phase products by residual gas analysis (RGA), the crust layer and bulk photoresist are removed by oxidation mechanisms similar to remote oxygen plasma strip processes. Above 350°C, it is found that O2 gas itself reacts with the photoresist but to a lesser extent than the O3/O2 mixture. Reactivity to silicon is lower than a typical remote oxygen plasma based on ~1 Å silicon loss measured on blanket films. This in-situ thermally activated oxidation reaction allows for subsequent wet processing without any queue time delay. The integrated process completely removes 5E15-1E16 at/cm2 high-dose implanted 193 nm photoresist with no residue on patterned substrates. Fig 1: In-situ thermally activated oxidation reaction in a single-wafer wet clean chamber process sequence consisting of (a) a dry ozone-oxygen gas environment, (b) ozone-oxygen decomposition and reaction on a heated wafer surface, (c) ozonated de-ionized water rinse in an N2 environment, (d) ammonium hydroxide-hydrogen peroxide clean in an N2 environment, and (e) a de-ionized water rinse and spin dry. Figure 1

Corrosion News

Corrosion News

Application of ozone gas for the stripping of fabric ink‐jet‐printed with reactive dyes

In this study, a novel process utilizing ozone was carried out for colour stripping of fabrics misprinted with reactive dyes in ink‐jet machines. The results of ozone applications were compared with conventional colour stripping process performed by thiourea dioxide (TUDO) and soda ash. In trials, cotton‐based and viscose‐based woven fabrics were used as these fabrics were the most utilized at the textile mill in which this study was performed. Different ozone treatment times (30, 45, 60 or 90 min) were tested to find optimum process time and it was found that process times depended on fabric type. Particularly, colour stripping on high density and thick fabrics were harder than low density and thin fabric types. Fabric strengths, whiteness indexes and chemical oxygen demand (COD) values were measured. Also energy, chemical and water consumptions were calculated. Consequently, it was found that the reduction of the COD value of effluent was up to 98%. The calculations showed that the savings in time and cost in ozone treatment were up to 77%. Satisfactory colour stripping and tensile strengths were achieved.

Thermally Activated Gas-Phase Chemical Reactions in a Single-Wafer Wet Clean Process

We investigate an alternative approach to conventional high dose ion-implanted photoresist strip and clean that replaces a remote plasma strip with a thermally activated, atmospheric gas-phase oxidation process and replaces sulfuric-peroxide mixture (SPM) chemistry with a de-ionized water/ozone (DIO3) chemistry. The gas phase oxidation process is first characterized in a mini-test chamber. Then the alternative dry and wet clean sequence is entirely processed in a modified single-wafer wet clean chamber. The atmospheric dry O3/O2 gas mixture decomposes and reacts with the ion-implanted photoresist wafer that is heated above 300 °C from the backside. 9,000 Å/min and 600 Å/min removal rates are measured on 193 nm photoresist and high dose implanted crust, respectively. Silicon reactivity from ellipsometry measurements is lower than a typical remote oxygen plasma based on ~1 Å silicon loss. The integrated process completely removes 5E15-1E16 at/cm2 high dose implanted 193 nm photoresist with no residue remaining on patterned substrates.