Performance Of Strips Research Articles

Enhancing the performance of strip and 180-deg slot waveguide bends for integrated optical waveguide modulator

Waveguide bends are essential structures for designing an integrated optical waveguide modulator (IOWM). However, reducing bending loss for strip and slot waveguide bends and obtaining a small increment of footprint size by bending the radius are challenging issues. We aim to evaluate whether using strip waveguides with an adiabatic bend reduces the bending loss and to obtain a specific length suitable for a V-shaped mode converter with a small increment of footprint size in the IOWM. Furthermore, a new 180-deg-bend structure for slot waveguides, to reduce bending loss, is investigated. The results of reducing bending radius (R) with a large coverage angle (αc) for strip waveguide bends revealed a low bending loss and simultaneously a reduction of the footprint size in the IOWM. For the 180-deg slot waveguide bend, both the bending and coupling losses were reduced by optimizing the taper and distance offset, which enhanced transmission power efficiency. We validated the feasibility and efficiency of the proposed bending strip and slot structures in IOWM, which is important for integrated optical applications.

High Anti-HCV Seroprevalence and Low Performance of ICT Strip in Diagnosing Hepatitis C Virus Infection in Children in Enugu Metropolis

Background:The lack of a vaccine for Hepatitis C virus (HCV) places children at a high risk of contracting the infection. It becomes necessary to accurately diagnose this infection for proper treatment as well as identifying potential risk factors for effective management.Aim:This study was conceived to assess the test performance of the commonly used Immunochromatographic test (ICT) strip and identify the associated clinical manifestations and risk factors of HCV in children in Enugu Metropolis.Method:A cross-sectional study involving randomly selected 270 children below six years of age was conducted in Enugu Nigeria. The subjects were screened for anti-HCV by ICT and Enzyme-Linked Immunosorbent Assay (ELISA) and the demographic, signs and symptoms and risk factors were collected.Results:A total of 50 out of 270 children were positive for anti-HCV with a seropositivity of 18.5%. ICT strip had a very low sensitivity of 38.00% with an accuracy of 88.52% in detecting anti-HCV. The presence of dark urine was associated (p= 0.01) with HCV infection.Conclusion:A seroprevalence of 18.5% of Anti-HCV was found in children below six years old in Enugu metropolis and the performance of ICT in diagnosing HCV infection was poor compared to ELISA.

Evaluating the Road-Bioretention Strip System from a Hydraulic Perspective—Case Studies

The two-dimensional overland flow simulation program, FullSWOF_2D, was revised to include submodules of determining infiltration by zones (Z) and grate-inlet (G) drainage from a 2D surface to a 1D pipe flow. The updated program, FullSWOF-ZG, was used to evaluate the performance of a road-bioretention strip (RBS) system and explore/understand key parameters of continuous RBS design. The program was validated using eight pervious surfaces under simulated rainfall events and tested with 20 experimental cases of a locally depressed curb inlet. The mean difference of simulated interception efficiencies (36.6%–86.0%) and observed interception efficiencies (34.8%–84.0%) of the curb inlet was 3.5%, which proves the program predicts the curb-inlet interception efficiency accurately. The 20 road-only and 20 RBS modeling cases were designed and modeled using the FullSWOF-ZG program. These case studies have different road lengths, curb inlet lengths, longitudinal slopes, cross slopes, bioretention-overflow inlet heights, and bioretention soil infiltration parameters. Only 34.6%–48.4% of the total runoff volume is intercepted by the RBS’s curb inlet under heavy rainfall (250 mm/h) and the remaining part of the runoff flows downstream along the road, which may cause local inundation and become a safety hazard. The curb inlet becomes the bottleneck of the RBS system that could impede the runoff flowing into the bioretention strip for detention and infiltration to improve the stormwater quality.

Experimental evaluation of shear connectors using reactive powder concrete under natural curing condition

In hybrid girder bridges, an efficient type of steel-concrete joint, the so called concrete filled steel cells (CFSCs), can be used to transfer forces between the steel and concrete girders. In the CFSCs, where shear connectors embedded in the concrete core, the bearing capacity of shear connectors is significantly affected by the side confinement effects of steel cells. Shrinkage of concrete may change the interfacial restraints from the steel cells. So far, the influence of concrete shrinkage on the behavior of shear connectors in CFSCs has not been deeply addressed. This paper presents an experimental study of the structural response of shear connectors using reactive powder concrete (RPC) encased in CFSCs. To determine the shrinkage effects of RPC, results from two series of experimental programs are discussed: the first series included testing of twelve plug-in type push-out specimens to assess the performance of perfobond strip (PBL) connectors. The second series consists of testing two plug-in type push-out specimens and eight CFSC type push-out specimens to evaluate the behavior of PBL and steel stud connectors. Results indicated that initial cracks due to shrinkage were observed at the steel cell/RPC interface, which was very detrimental to connectors’ stiffness and strengths. Comparing to connectors with exposed RPC, the average ultimate bond strength at the CFSC steel cell/RPC interface dropped by 15%. Results also indicated that failure of steel stud and transverse steel rebar was barely influenced by RPC shrinkage. Furthermore, a comparison between experimental and predicting results was conducted to assess the applicability of the existing analytical models in predicting the behavior of PBL embedded in RPC with shrinkage.

Functionalized reduced graphene oxide as a lateral flow immuneassay label for one-step detection of Escherichia coli O157:H7

In this study, graphene oxide (GO) and reduced graphene oxide (rGO) were used as visual labels in a lateral flow assay for detection of E. coli O157:H7. The color intensity was employed for the quantitative measurements of the target bacteria. Quantitative results showed that in comparison to GO, rGO can provide higher color intensity owing to enhanced light absorption following chemical reduction. Our results confirm that the visual limit of detection of the target bacteria by rGO is ∼105 colony forming unit per milliliter (CFU/ml), which closely compares with current alternative techniques using gold nanoparticles. The performance and practicability of the rGO-based test strips for detection of the target bacteria in milk and drinking water were validated with conventional plating and colony counting techniques. Results suggest that the proposed lateral flow assay is sensitive, specific, and affordable. It has also the potential to become a widely used detection technique for E. coli O157:H7 and a wide variety of other analytes.

Effect of filling pressure in jetting dispenser on the performance of blood glucose test strips using immersion gold-plated printed circuit board.

To ensure accurate glucose readings when dispensing glucose oxidase enzyme solution from a jetting dispenser onto glucose test strips fabricated from an immersion gold-plated printed circuit board, every drop of the enzyme solution needs to have nearly the same weight and to be dispensed on the reaction zone of the test strips. Experimental results in this study show that the filling pressure in the fluid reservoir containing the glucose enzyme solution to dispense onto the test strips significantly affect the glucose test results. A filling pressure of 12 psi produces test strips with lower coefficient of variation and standard deviation than 10 and 14 psi. Proper filling pressure for dispensing glucose enzyme onto glucose test strips needs to be determined for any enzyme compound formulation.

Dialysis assisted ligand exchange on gold nanorods: Amplification of the performance of a lateral flow immunoassay for E. coli O157:H7.

Ligand exchange on the surface of gold nanorods (AuNRs) is widely used, but conventional methods usually require multiple centrifugation cycles to completely remove cetyltrimethylammonium bromide (CTAB). This can lead to undesired aggregation of AuNRs. A dialysis-assisted protocol is described here for ligand exchange on AuNRs. Dialysis driven by a concentration gradient is shown to be a powerful tool to separate CTAB from aqueous solutions. The concentration gradient of CTAB in a dialysis bag can avoid the possible aggregation of AuNRs that can be caused by drastic environmental changes. It also supports the rate of ligand exchange on the surfaces of the AuNRs. The modified AuNRs were employed in a lateral-flow test strip immunoassay (LFTS-IAs) for the food pathogen E. coli O157:H7 in order to study of efficiency of ligand exchange. Compared to AuNRs where ligand exchange was performed via multiple centrifugation cycles, the AuNRs prepared by dialysis-assisted ligand exchange show improved conjugation to antibody and enhanced visual signals in the test line of the LFTS-IAs. A portable strip reader (absorption wavelength = 525nm) is used to records the testing results. The sensitivity of AuNRs modified by dialysis has been achieved even as low as 1 × 102cfu·mL-1 in a short time (within 15min), and the working range is 1 × 102 to 1 × 106cfu·mL-1, which is superior over the detection performance of conventional test strip using AuNRs modified by centrifugation. Graphical abstract Schematic presentation of the ligand exchange of AuNRs. TheAuNRs were dialysed in water to decrease the CTAB concentration. Then, 11-mercaptoundecanoic acid (MUA) replaces the CTAB capped on the surface of AuNRs. The modified AuNRs were employed in a lateral flow immunoassayfor E. coli O157:H7.

Overview of the Quench Heater Performance for MQXF, the Nb3Sn Low-<italic>β</italic> Quadrupole for the High Luminosity LHC

In the framework of the high-luminosity upgrade of the Large Hadron Collider, the U.S. LARP collaboration and CERN are jointly developing a 150 mm aperture Nb3Sn quadrupole for the LHC interaction regions. Due to the large stored energy density and the low copper stabilizer section, the quench protection of these magnets is particularly challenging, relying on a combination of quench heaters attached to the coil surface and coupling loss induced quench (CLIQ) units electrically connected to the coils. This paper summarizes the performance of the quench heater strips in different configurations relevant to machine operation. The analysis is focused on the inner layer quench heaters, where several heater strips failed during powering tests. Failure modes are discussed in order to address the technology issues and provide guidance for future tests.

Capillary rise of liquids in thermally sprayed porous copper wicks

Porous copper coatings, which act as wicks for liquid transport, were fabricated using a flame spraying process. Channels to enhance liquid flow were made in some of the porous copper coatings by placing pieces of aluminum wire mesh on the copper substrate before spraying. Coatings were made with porosity varying from 2 to 44%, and groove width ranging from 0.16 to 0.53 mm. The capillary performance of the coatings was evaluated experimentally by measuring the rate-of-rise of ethanol in the coatings. The capillary performance of the porous copper strips were evaluated by standing them vertically in a pool of ethanol and measuring both the rate of liquid rise using an infra-red camera and their weight increase. The rate of rise increased with coating porosity, and decreased with channel width. Increasing channel size improved the permeability of the coatings to liquid flow while decreasing their width increased capillary pressure and the height to which liquid rises. An analytical solution of capillary rise in porous media was used to predict the rate of liquid rise as a function of the effective porosity of the coatings, which combines the volume of both the pores and the channels in the coating.

Bond performance of NSM CFRP strips embedded in concrete using direct pull-out testing with cementitious adhesive made with graphene oxide

Concrete structures are normally strengthened using fibre reinforced polymer (FRP) with epoxy adhesives and polymer cementitious mortars. Epoxy adhesives have significant issues, such as the release of toxic fumes throughout curing, loss of strength and stiffness when exposed to hot temperatures, and low permeability and weakness to UV radiation. In the case of polymer cementitious adhesives, their properties are adversely affected by hydrothermal conditions. An innovative high-strength self-compacting non-polymer cementitious adhesive (IHSSC-CA) has recently been developed by the authors which uses graphene oxide and cementitious materials. This paper presents the bond response of carbon FRP strips bonded to concrete substrate using near-surface mounted (NSM) technique with IHSSC-CA, epoxy and polymer cement-based adhesives using direct pull-out tests. The behaviour of each adhesive is presented and compared and the local bond-slip relationship is calculated. Finally, an analytical model is proposed to predict the ultimate pull-out force (bond strength). The results of this study confirm the effectiveness of using IHSSC-CA to improve the bond strength, stiffness, CFRP strip utilisation, ductility and residual strength of NSM CFRP system. Moreover, the proposed analytical model can simulate experimental conditions reasonably well.

Effects of tilted angle of Bragg facets on the performance of successive strips based Bragg concave diffraction grating

The effects of the tilted angle of facets on the diffraction orders, diffraction spectra, dispersion power, and the neighbor channel crosstalk of successive etching strips based Bragg concave diffraction grating (Bragg-CDG) are studied in this paper. The electric field distribution and diffraction spectra of four Bragg-CDGs with different tilted angles are calculated by numerical simulations. With the reflection condition of Bragg facets constant, the blazing order cannot change with the titled angle. As the tilted angle increases, the number of diffraction orders of Bragg-CDG will decrease, thereby concentrating more energy on the blazing order and improving the uniformity of diffraction spectra. In addition, the dispersion power of Bragg-CDG can be improved and the neighbor channel crosstalk of devices can be reduced by increasing the tilted angle. This work is beneficial to optimize the performance of Bragg-CDG.

Comparative performance of lissamine green stains.

To investigate the performance of lissamine green strips from different manufacturers. Additionally, the repeatability, need for sequential dye instillation and impact of repeated lid evertion on lid wiper staining were assessed. Study 1 was a prospective, randomised cross-over study where controlled volumes of lissamine green solution prepared from strips (Biotech, Lissaver, GreenGlo, OPGreen) were instilled (right eye: single; left eye: double instillation) on five different days, with OPGreen being tested twice. Lids were everted and digital photographs taken, which were later assessed by a masked observer. Study 2 was an investigator-masked, randomised, controlled study testing the impact of single versus repeated lid evertion. Lid wiper staining was graded (0 to 3 in 0.5 steps). Lid wiper staining differed significantly between lissamine green solutions, with GreenGlo showing the highest amount of staining, and Lissaver the least (all p>0.009). There were no differences in lid wiper staining over two days, using the OPGreen solution (all p>0.05). The number of drops instilled (single versus double) did not significantly affect lid wiper staining (all p>0.05). Repeated lid evertion increased lid wiper staining (p=0.007 when combined with double drop instillation). Light absorbance patterns and measured concentrations aligned with clinical findings. There were significant differences in performance between lissamine green solutions. Lid wiper staining was impacted by repeated lid evertion but sequential instillation and use of the Korb grading scale provided little advantage over simpler methods Clinicians must consider this when investigating lid wipers, especially when interpreting a negative finding.

Modelling forest regeneration for performance-oriented riparian buffer strips

Riparian buffer strips (RBS) play an important role in the conservation of water bodies. Yet to date the increasing degradation of riparian vegetation is a major concern due to the inherent risk it poses to quality and quantity of drinkable water. In turn, forest regeneration is known to be a process that evolves in a time-scale of years, such that the regeneration of a forested area after a perturbation can take several decades. In this context, the exploration of models of vegetation growth can contribute to the understanding and acknowledgement of diverse aspects of such phenoma. Further, from the standpoint of conservation projects, the application of models allows the assessment of different future scenarios resulting from the application of different management practices, thus allowing anticipating the likely outcomes of the management process. In this paper, we study the application of the diffusive-logistic model (DLG model) to the problem of forest regeneration. We concentrate in vegetation belonging to permanent preservation areas, such as RBS. The main contribution of this study is to propose and illustrate a thorough methodology applicable as auxiliary assessment and design tool for conservation projects. The study is developed in two steps. We build upon recent results that study on the performance of riparian buffer strips in the removal of nitrogen in agricultural catchments in which an Artificial Neural Network Ensemble (ANNE) was applied to evaluate the riparian buffer strip width needed to accomplish filtering of 90% of the residual nitrogen. On this basis, we calibrate and validate the parameters of the diffusive-logistic model of forest growth to estimate the evolution of regeneration in riparian buffer strips, considering the buffer widths obtained by the ANNE. We implement the solution in GPGPU (General Purpose Graphics Processing Unit) and then simulate for forty years ahead to verify the likely effect of conservation upon the riparian buffer strips in the watershed. The results of calibration and validation show that the diffusive-logistic model provides a rather accurate temporal and spatial account of forest regeneration. The application of the model to a case study of the Ligeiro River watershed, Brazil, shows that the model can provide valuable insights for decision-making in the context of environmental conservation and management.

Dynamics of runoff and sediment trapping performance of vegetative filter strips: Run-on experiments and modeling

Vegetative filter strips (VFSs) are a labor-saving and cost-effective agricultural best management practice to trap water runoff and sediment from the source areas. They also provide forage and/or fuel and are therefore potentially profitable for land owners. VFSs are however a dynamic system: the runoff delivery ratio (RDR) and sediment delivery ratio (SDR) vary with growth stage and vegetation types. The impacts of vegetation characteristics as well as soil physical properties modified by vegetation growth, on the RDR and SDR of VFS were evaluated by a flume experiment. Two plant species (cocksfoot (Dactylis glomerata L.) and white clover (Trifolium repens L.)) were tested at three stages in the growing season of 2016 (May, July, and August). The measured RDR and SDR were compared with the simulated results from Vegetative Filter Strip Modeling System (VFSMOD). In the early stages of the growing season, the cocksfoot formed a dense network of stems with high strip Manning's roughness faster than white clover. The runoff and sediment trapping effects of the white clover VFS were greater than that of cocksfoot VFS in all the three stages (lower RDR and SDR). This is likely attributed to strongly tillering, creeping stem posture and high infiltration capacity of the white clover VFS. VFSMOD simulated the RDR and SDR reliably except under low vegetation coverage conditions (white clover in May). The results suggested that (1) both soil physical properties and vegetation characteristics should be considered for the species-specific, temporally variable performance of VFS; and (2) when using VFSMOD inform the VFS design, modelers should take the dynamics of vegetation, mainly through vertical saturated hydraulic conductivity, stem spacing and strip Manning's roughness into account, and select parameters that reflect the actual field conditions.

Effect of reinforcement geometry on the performance of a reduced-scale strip footing model supported on geocell reinforced sand

Geocell is an effective type of geosynthetics for improving the performance of reinforced soil foundations due to provision of lateral confinement for the infill soil. In this research, in order to study the bearing pressure-settlement response of geocell reinforced sand, a reduced-scale physical model is developed and geocells with various geometrical dimensions (height, pocket size and width) produced from woven geotextile are used to reinforce sand bed. Strip footing model is then loaded monotonically to ultimate failure level and the influence of geocell geometrical properties on the improvement in bearing capacity and settlement of footing is described. The results show that by increasing height and decreasing pocket size of geocell, the beneficial effect of geocell reinforcement increases substantially. For the highest geocell used in the tests at settlement level of 6%, improvement in bearing capacity and percentage reduction in footing settlement is obtained as 2.1 and 48% respectively. The optimum width of geocell is determined five times the foundation width beyond which the improvement effect is negligible. It is also concluded that substituting a single layer of geocell reinforcement with 2 half-height and 4 quarter-height geocell layers results in 10% and 22% decrease in the ultimate bearing capacity respectively.

Hollow Au-Ag Nanoparticles Labeled Immunochromatography Strip for Highly Sensitive Detection of Clenbuterol

The probe materials play a significant role in improving the detection efficiency and sensitivity of lateral-flow immunochromatographic test strip (ICTS). Unlike conventional ICTS assay usually uses single-component, solid gold nanoparticles as labeled probes, in our present study, a bimetallic, hollow Au-Ag nanoparticles (NPs) labeled ICTS was successfully developed for the detection of clenbuterol (CLE). The hollow Au-Ag NPs with different Au/Ag mole ratio and tunable size were synthesized by varying the volume ratio of [HAuCl4]:[Ag NPs] via the galvanic replacement reaction. The surface of hollow Ag-Au NPs was functionalized with 11-mercaptoundecanoic acid (MUA) for further covalently bonded with anti-CLE monoclonal antibody. Overall size of the Au-Ag NPs, size of the holes within individual NPs and also Au/Ag mole ratio have been systematically optimized to amplify both the visual inspection signals and the quantitative data. The sensitivity of optimized hollow Au-Ag NPs probes has been achieved even as low as 2 ppb in a short time (within 15 min), which is superior over the detection performance of conventional test strip using Au NPs. The optimized hollow Au-Ag NPs labeled test strip can be used as an ideal candidate for the rapid screening of CLE in food samples.

Carbon Nanoparticles Based Electrochemical Biosensor Strip for Detection of Japanese Encephalitis Virus

We reported a disposable and sensitive electrochemical biosensor strip based on carbon nanoparticles modified screen-printed carbon electrode (SPCE) for rapid and sensitive detection of Japanese Encephalitis Virus (JEV). Amino group functionalized carbon nanoparticles were prepared from preformed chitosan nanoparticles. Japanese Encephalitis Virus (JEV) antibody was immobilized onto the surfaces of carbon nanoparticles through amide bonds formation between amino groups of carbon nanoparticles and carboxylic groups of JEV antibody. The analytical performance of SPCE electrochemical biosensor strip was characterized using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). SPCE electrochemical biosensor strip exhibited a linear detection range of 1–20 ngmL−1 with a low detection limit of 0.36 ngmL−1 (at S/N = 3) for JEV, detection sensitivity was 0.024 ngmL−1 for JEV, and analysis results were obtainable within 10 minutes. The potential clinical application of this SPCE electrochemical biosensor strip was demonstrated by the detection of JEV in human serum.

Effects of a Novel Whitening Formulation on Dental Enamel.

The goal of this study was to evaluate the enamel whitening effects of 2 new test formulations, one of which was a rinse, and the other a whitening strip. Forty enamel chips were prepared from 20 healthy extracted teeth (2 from each tooth). After pre-staining and colorimetry to measure L* and b* values, 20 matched samples were immersed in either test or control rinses, and then colorimetry was performed again after 1 hr, 2 hr, 3 hr, 6 hr, 12 hr, 24 hr and 48 hrs (Each hour equates to one month of clinical use at the recommended dosage of 1 minute exposure 2 times a day). The remaining 20 matched samples were exposed to the test or control whitening strips and colorimetry was performed every 30 minutes for a total of 10 treatments. Overall, the whitening performance of test and control strips was similar. The test and control rinses had a similar lightening effect over the first 3 hours (equivalent to 3 months of clinical use). Subsequently, the control rinse continued to lighten samples, whereas the test rinse had little further effect. Test and control-whitening strips showed similar effects; over time whitening strips showed a greater lightening effect than whitening rinses.

Disposable Carbon Dots Modified Screen Printed Carbon Electrode Electrochemical Sensor Strip for Selective Detection of Ferric Ions

A disposable electrochemical sensor strip based on carbon nanodots (C-Dots) modified screen printed carbon electrode (SPCE) was fabricated for selective detection of ferric ions (Fe3+) in aqueous solution. C-Dots of mean diameters within the range of 1–7 nm were synthesized electrochemically from spent battery carbon rods. The analytical performance of this electrochemical sensor strip was characterized using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The deposition of C-Dots had enhanced the electron-transfer kinetics and current intensity of the SPCE remarkably by 734% as compared to that of unmodified SPCE. Under optimized conditions, the electrochemical sensor strip exhibited a linear detection range of 0.5 to 25.0 ppm Fe3+ with a limit of detection (LOD) of 0.44±0.04 ppm (at S/N ratio = 3). Validation of results by the electrochemical sensor strip was done by comparing analysis results obtained using an Atomic Absorption Spectrometer (AAS).

Infiltration capacity of roadside filter strips with non-uniform overland flow

The side slope to a roadside swale (drainage ditch) constitutes a filter strip that has potential for infiltration of road runoff, thereby serving as a stormwater quantity and quality control mechanism. A total of thirty-two tests were performed during three seasons in four different highways located in the Minneapolis-St. Paul metropolitan area, MN to analyze the infiltration performance of roadside filter strips and the effect of fractional coverage of water on infiltration. Three different application rates were used in the experiments. All the tests showed that water flow on the lateral slope of a roadside swale is concentrated in fingers, instead of sheet flow, at the typical road runoff intensities for which infiltration practices are utilized to improve surface water quality. A linear relationship between flux of water from the road and fraction of wetted surface was observed, for the intensities tested.The average percentage infiltration of the medium road runoff rate (1.55×10−4m2/s, without direct rainfall) experiments performed in fall was 85% and in spring 70%. For the high road runoff rate (3.1×10−4m2/s, without direct rainfall) tests the average amount of water infiltrated was 47% and for the low road runoff rate (7.76×10−5m2/s, without direct rainfall) tests it was 69%, both set of tests performed in spring and summer. The saturated hydraulic conductivity of swale soil was high, relative to the values typical of laboratory permeameter measurements for these types of soils. This is believed to be due to the macropores generated by vegetation roots, activity of macrofauna (e.g. earthworms), and construction/maintenance procedures. The trend was to have more infiltration when the saturated hydraulic conductivity was higher and for a greater side slope length, as expected. The vegetation, type of soil and length of the side slope are important to consider for constructing and maintaining roadside swales that will be efficient as stormwater control measures. These measurements indicate that the filter strip portion of a roadside swale typically infiltrates a substantial fraction of road runoff. However, the measurements do not incorporate the influence of direct rainfall upon the infiltration into filter strips.