Standard Strip Research Articles

Transition Effect on the Flow Dynamics in a Compressor Blade Passage

An experimental investigation was carried out to study the effect of the boundary layer transition on the flow dynamics in the blade passage of a compressor cascade. A model of a turbine compressor passage was designed and assembled in a transonic wind tunnel for this purpose. Two different flow control methods were used in the experiment to induce the transition upstream of the shock wave, one concerning the microstep application and the other using distributed roughness strips. Two locations of spanwise microsteps for the transition trigger were chosen, one at the leading edge and the other closer to the shock wave position. The distributed roughness in the form of standard sandpaper strips with different heights was applied in three various locations on the blade upstream of the shock. The main objective of investigations is to present the influence of the laminar and turbulent shock wave‐boundary layer interaction on the flow dynamics in a compressor fan passage, and the specific objective is to show how the parameters of particular transition control methods affect the flow dynamics in the investigated channel. The major challenge for this research was to minimize the disturbance caused by the microstep or roughness to the laminar boundary layer, while still ensuring a successful transition. Very interesting results were obtained in the flow control application for the boundary layer transition control, demonstrating a positive effect on the flow unsteadiness in changing the nature of the interaction.

Development of inline closed-loop vibration control in progressive die stamping using finite element simulation

Modern progressive dies are increasingly equipped with integrated sensors and actuators, thus enabling an improvement of the manufacturing process and an inline monitoring of the component quality. The design of the tooling is determined at an early stage and is largely based on the desired product and the specific production stages such as blanking, forming and punching. Nevertheless, malfunctions such as strip vibrations cannot always be foreseen and may occur during operation time, which may lead to reduced component quality and in the worst case to component collision or a damage of the tooling. Therefore, complex reworking or a reduction of the stroke rate and thus lower output quantity are often necessary for a reliable and stable process. Strip vibrations are often caused by the highly dynamic transportation of the strip in the tool and can have various causes. Among others, passive tooling components such as spring-loaded, hard stop limited strip lifter can be the cause of such vibrations. Strip lifter are always necessary when three-dimensional components are produced and have to be lifted out of the die for the feeding phase. The feeding phase takes place between two strokes of the stamping process. This work is aiming for a control strategy to suppress strip vibrations in various progressive die stamping processes based on closed-loop controlled active strip lifter. These strip lifter combine the spring-loaded passive standard strip lifter with an additional PID-controlled actuator. Taking the dynamics of the flexible strip during operation into account, a Finite Element Analysis (FEA) model of a progressive die tooling system is created. For the design of the control algorithm, the FEA model is connected to an environment for model-based design in a co-simulation. This approach allows modelling the influence of arbitrary control parameter settings on the movement curve of the strip, aiming for an increased stroke rate.

Eye bank versus surgeon prepared DMEK tissues: influence on adhesion and re-bubbling rate

AimTo investigate the difference in adhesion and rebubbling rate between eye bank and surgeon prepared Descemet membrane endothelial keratoplasty (DMEK) tissues.MethodsLaboratory and clinical retrospective comparative interventional case series. Research corneal...

GBT Analysis of Steel-Concrete Composite Beams: Recent Developments

This paper reports the most recent developments concerning Generalized Beam Theory (GBT) formulations, and corresponding finite element implementations, for steel-concrete composite beams. These formulations are able to perform the following types of analysis: (i) materially nonlinear analysis, to calculate the beam load-displacement response, up to collapse, including steel plasticity, concrete cracking/crushing and shear lag effects, (ii) bifurcation (linear stability) analysis, to obtain local/distortional bifurcation loads and buckling mode shapes of beams subjected to negative (hogging) bending, accounting for shear lag and concrete cracking effects and (iii) long-term service analysis including creep, cracking and arbitrary cross-section deformation (which includes shear lag) effects. The potential (computational efficiency and accuracy) of the proposed GBT-based finite elements is illustrated through several numerical examples. For comparison purposes, results obtained with standard finite strip and shell/brick finite element models are provided.

Reliability of ultra-short indices for autonomic dysfunction in dyslipidemia.

Dyslipidemia is associated with autonomic nervous system (ANS) dysfunction. Heart rate variability (HRV) is a powerful tool for evaluating the ANS and for cardiovascular risk stratification. Yet, the methodologies used are impractical in most clinical settings and therefore, are usually not applied. The current study aimed to evaluate the reliability of ultra-short HRV parameters, which are easily calculated from any standard ECG, as a practical method for ANS study, with a focus on patients with dyslipidemia. Fifty-nine volunteers with dyslipidemia underwent HRV study of parametric and power spectral indices according to accepted methods. Correlations were calculated between ultra-short HRV indices (five 1-min and five 10-s segments) and standard 5-min recordings. Correlations were found between 10-s and 1-min RMSSD and 5-min recordings (mean Pearson ρ correlation coefficients of 0.913 and 0.944, respectively, and mean concordance correlation coefficients of 0.855 and 0.938, respectively). Associations were found between other ultra-short HRV parameters (SDNN, maximum RR, minimum RR, pNN50, ln(RMSSD) and 5-min recordings. In addition, average RR, HRV-TI, NN50, TP, LF/HF, ln(SDNN), ln(HRV-TI), ln(TP) and ln(LF/HF) from 1-min recordings were associated with 5-min values. In conclusion, some ultra-short HRV parameters can be used for ANS evaluation and presumably, for cardiovascular risk stratification among patients with dyslipidemia. These parameters seem to be of great practical value for both inpatient and outpatient settings, because most can be calculated from a standard 10-s ECG strip. The prognostic implications of ECG-derived, ultra-short HRV parameters in patients with dyslipidemia should be further evaluated in future studies.

Measurements of an AC-LGAD strip sensor with a 120 GeV proton beam

The development of detectors that provide high resolution in four dimensions has attracted wide-spread interest in the scientific community for several applications in high-energy physics, nuclear physics, medical imaging, mass spectroscopy as well as quantum information. LGAD silicon sensors with finely segmented AC-coupled electrodes can provide precise spatial and timing measurements of incident minimum ionizing particles. Such AC-coupled LGADs, also known as AC-LGADs, are therefore considered as candidates for future detectors to provide 4-dimensional measurements in a single sensing device with 100% fill factor. This article presents the first characterization of an AC-LGAD sensor with a proton beam of 120 GeV momentum at Fermilab. The sensor consists of strips with 80 μm width, fabricated at Brookhaven National Laboratory. The signal properties, efficiency, spatial, and time resolution are presented. The experimental results show that the time resolution of such an AC-LGAD is compatible to standard LGADs with similar gain, and that AC-LGADs can be segmented with fine pitches as standard strip or pixel detectors.

Effect of different surface treatments on bond strength between zirconia posts and root surfaces

Aim: In recent years, especially with the increase in aesthetic demands, there has been a requirement to use the best aesthetic materials for dental restorations. These restorations are especially needed in those teeth that have crown loss due to a tooth fracture or extreme anterior tooth decay, post-core treatment has been applied as getting support by tooth roots. the aesthetic disadvantages and making use of the strength resistance of various metals. In this case, zirconium, which is a white‑coloured metal, is preferred. In this study, zirconia posts with different surface treatments were cemented to the root canal and bond strength was then evaluated.
 Materials and Methods: Forty mandibular second premolar teeth were used in this study. Crowns of all teeth were removed to 14 mm from the enamel-cement margin by separation under irrigation. Root canals were cleaned, shaped and filled. Teeth were kept in distilled water while zirconia posts were prepared. Zirconia posts were divided into four groups according to the surface treatment methods as follows: a control group, a CoJet applied group, a sandblasting+laser group and an Er:YAG laser group. The Er:YAG laser was administered at 450 mJ at 10 Hz for 60 seconds with a 100-μs pulse duration. Surface-treated posts were bonded to the root canal with Panavia F cement. Cores were made with the standardized strip crowns. 5000 cycles, 5-55 °C thermal cycle applied with transition time at 5 seconds. For push-out tests, roots were embedded in translucent acrylic resin and coronal, middle third and apical sections were cut into 1.5-mm slices. The maximum load at failure was recorded for each specimen in newtons and then converted into megapascals (MPa). Each specimen was inspected with a scanning electron microscope (SEM) at a magnification of 100 X. Data were analysed using Games‑Howell tests with a significance level of 0.05.
 Results: The coronal section from Group 3 had the highest mean push-out bond strength (18.01 MPa), while the apical section from Group 1 had the lowest (4.49 MPa). Surface treatments had no significant effect on the mean push-out bond strengths of zirconia posts (p > 0.05). However, dividing the root canal into three sections had a significant effect on bond strength (p < 0.05). When the results were evaluated for all groups, the push-out bond strength was highest in the coronal section, then in the middle third and the lowest in the apical section.
 
 How to cite this article:
 Dündar Yılmaz B, İzgi AD. Effect of different surface treatments on bond strength between zirconia posts and root surfaces. Int Dent Res 2020;10(2):49-54. https://doi.org/10.5577/intdentres.2020.vol10.no2.4
 
 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Multifunctional Tissue-Adhesive Cryogel Wound Dressing for Rapid Nonpressing Surface Hemorrhage and Wound Repair.

Cryogels with tissue adhesion have great potential as wound dressings for rapid hemostasis for uncontrollable nonpressing surface hemorrhage and wound healing, but their use has not been reported previously. Herein, we designed a series of antibacterial and antioxidant tissue-adhesive cryogels based on quaternized chitosan (QCS) and polydopamine (PDA). These cryogels had good blood cell and platelet adhesion, enrichment, and activation properties for rapid nonpressing surface hemostasis and wound healing. The cryogels exhibited outstanding mechanical strength and easy removability, antioxidant activity, and NIR photothermal-enhanced antibacterial performance. The cryogels showed much better hemostasis than gauze and gelatin sponge in a standardized strip rat liver injury model, a standardized circular rabbit liver section model, and a pig skin laceration model. Furthermore, the excellent hemostatic performance of the QCS/PDA2.0 cryogel (containing 20 mg/mL QCS and 2.0 mg/mL PDA) for coagulopathic hemorrhages was confirmed in a standardized coagulation disorder rabbit circular liver section model. In addition, the QCS/PDA2.0 cryogel promoted rapid hemostasis in a deep noncompressible wound and a much better wound healing effect than a chitosan sponge and Tegaderm film in a full-thickness skin defect model. Overall, these multifunctional tissue-adhesive cryogels with excellent hemostatic performance and enhanced wound healing properties are suitable candidates for tissue-adhesive hemostat and wound healing dressings.

Fertility Outcome after CO2 Laser Vaporization versus Cystectomy in Women with Ovarian Endometrioma: A Comparative Study

To assess the postoperative likelihood of conception in patients with endometriomas managed by either CO2 laser vaporization or cystectomy. A retrospective study with prospective recording of data. University hospital. One hundred and forty-two patients with symptomatic endometriomas. Patients underwent a standardized laparoscopic stripping technique (Group 1) or cyst vaporization with CO2 fiber laser (Group 2). Patients wishing to become pregnant were allowed to attempt a spontaneous conception after surgery. If spontaneous conception failed, patients were referred for in vitro fertilization (IVF). The primary objective was to compare pregnancy rates between the 2 groups. The secondary objective was the identification of independent predictors of pregnancy. Thirty-nine women in Group 1 (53.4%) and 39 women in Group 2 (56.5%) desired to conceive after surgery. Three patients (7.7%) in Group 1 became pregnant following donor-IVF and were excluded. Pregnancies were recorded in 72.2% of patients treated with cystectomy and in 74.3% of those managed with CO2 fiber laser (p = .83). Twenty patients (55.6%) in Group 1 and 14 patients (35.9%) in Group 2 conceived spontaneously (p = .08). Among patients who failed spontaneous conception, 21 patients (28%) achieved pregnancy through IVF (Group 1: n = 6, 16.7%; Group 2: n = 15, 38.5%; p = .08). Twenty patients (26.7%) never became pregnant. Age at the time of surgery (odds ratio (OR) = 0.86; 95% Confidence intervals (CI): 0.78-0.96, p = .002) and duration of infertility (OR=0.80; 95% CI: 0.69-0.92, p = .006) were identified as independent indicators for pregnancy. CO2laser-treated endometrioma is associated withpregnancy ratesequalto those observed after cystectomy and favorable IVF outcomes. The one step CO2fiber laser technique may represent a viable alternative to cystectomy.

Fe3O4@Au SERS tags-based lateral flow assay for simultaneous detection of serum amyloid A and C-reactive protein in unprocessed blood sample

Accurate detection of mutiple biomarkers in unprocessed blood via lateral flow immunoassay (LFA) strips remains challenging. Herein, we reported a novel surface-enhanced Raman scattering (SERS)-based LFA strip for ultrasensitive and simultaneous analysis of dual infection biomarkers by using functionalized Fe3O4@Au magnetic nanoparticles (MNPs). Antibody-modified Fe3O4@Au MNPs were designed as SERS nanotags and efficient enrichment tool. The target infection biomarkers were quickly captured and enriched from the blood sample by Fe3O4@Au nanotags. After washing to remove impurities, Fe3O4@Au nanotags acted as high-performance SERS reporters for quantitative detection of the target in the LFA strip. Through this strategy, the proposed Fe3O4@Au based LFA allowed quantified analysis of target infection biomarkers in unprocessed blood samples with the limits of detection of 0.1 ng/mL and 0.01 ng/mL for serum amyloid A (SAA) and C-reactive protein (CRP), respectively. By comparison, the proposed assay for SAA and CRP was 100-fold and 1000-fold more sensitive than standard colloidal gold strip by using the same antibodies, respectively. This magnetic SERS strip also exhibited excellent stability, specificity, and selectivity for complex samples and could be used as an effective tool for infectious disease diagnostics.

A High Accuracy Ion Conductance Imaging Method Based on the Approach Curve Spectrum

Scanning ion conductance microscopy (SICM), as an emerging non-contact in situ topography measurement tool with nano resolution, has been increasingly used in recent years in biomedicine, electrochemistry and materials science. In the conventional measurement method of SICM, the sample topography is constructed according to the position of the probe at the feedback threshold of the ion current. Nevertheless, for different structures, a constant threshold cannot maintain a constant probe-sample distance. This phenomenon makes the measurement topography inconsistent with the real sample surface. In order to solve this problem and improve the measurement accuracy of SICM, a new ion conductance imaging method based on the approach curve spectrum is proposed in this work. In the new method, the local feature around the measurement point is firstly evaluated according to the change rate of ion current. Secondly, based on the local feature, the corresponding approach curve is searched from the prior approach curve spectrum to accurately evaluate the distance between the probe and the sample. Finally, the sample topography is constructed by the probe position subtracting the probe-sample distance. In this paper, we verify the feasibility of the new imaging method by combining finite element theory and experiments. To examine the measurement accuracy, the standard strip silicon and cylindrical polydimethylsiloxane (PDMS) samples are tested, and the improved imaging method can obtain the topography closer to the real samples and reduce the volumetric measurement error by 5.4%. The implementation of the new imaging method will further promote SICM application in related research fields.

An immunoassay cassette with a handheld reader for HIV urine testing in point-of-care diagnostics.

Currently, most HIV tests are performed with blood samples, or alternatively saliva samples are used for HIV testing. Simple HIV tests need to be performed in hospitals or other medical agencies instead of more invasive HIV blood tests. To enable point-of-care (POC) HIV diagnostics, based on a recently developed lateral flow strip for HIV urine testing, a microfluidic immunoassay cassette with a handheld optical reader is developed. Based on lateral flow strip with gold colloid reporter, the integrated immunoassay cassette can perform sample introduction, metering, discharging, applying and detection which simplifies HIV testing. An indicator is incorporated into the cassette to guide sample introduction based on color change, and further, the excess test sample is stored inside the sealed cassette to avoid any contamination. The low-cost handheld optical reader can provide a test result within a few seconds, which is useful for simple, sensitive and affordable HIV onsite detection. Instead of using normal white LEDs, a customized back light module embedded with green LEDs is adopted to illuminate the lateral flow strip with an appropriate working current to achieve optimal performance. Compared to the standard lateral flow strips using a benchtop reader, with the disposable immunoassay cassette assisted by the handheld optical reader, more convenient, easier-to-operate, and more affordable HIV urine testing can be achieved in POC diagnostics.

Research on image processing algorithm of immune colloidal gold test paper detection

In order to better solve the problem of automatic identification of quality control line and detection line in the detection of gold standard test strip, this paper proposes to collect the image information of gold standard test strip after color rendering through CMOS sensor, preprocess the obtained information, transform RGB image into gray image, build cloud model in the CIELAB/HSV/HSL space, and apply the improved AdaBoost algorithm to determine the position of detection line and quality control line Place. Compared with the traditional template matching method, it improves the accuracy and accuracy of recognition.

Calibration of a Fourier transform spectrometer using its internal lamp as a reference source

Spectral radiance responsivity calibration of Fourier transform spectrometers (FTSs) used for solar radiance observations is important for removing systematic errors resulting from the different spectral responsivities of each instrument. In this study, the spectral responsivity of an FTS with a Globar lamp as an internal light source was calibrated, and its temperatures were determined without direct temperature measurement through nonlinear fitting using a modified three-temperature method (referred to hereafter as m-TTM). Our calibration results were verified using a standard tungsten strip lamp. Furthermore, the spectral radiance results obtained with three different apertures proved that the FTS radiance has a systematic error of approximately 5%, deviating from that of the standard strip lamp owing to an assumption of a perfect emissivity. In particular, the real emissivity of the Globar lamp, for which the value still includes an instrumental optical error, in the range of 4000 cm−1 to 8000 cm−1 (for the InSb detector) was found to be approximately 0.94–0.98 after correction by a supplementary measurement using a certified standard strip lamp as an external light source. The deviations of the results for all the apertures were less than ±1%. Therefore, this study showed that the accurate responsivity calibration of an FTS with an internal light source such as a Globar lamp could be obtained by employing the m-TTM.

Device performance of standard strip, slot and hybrid plasmonic μ-ring resonator: a comparative study

ABSTRACT In this paper, we presented three μ-ring resonator structures based on the standard strip, slot and hybrid plasmonic waveguides based on the SOI platform. A standard strip waveguide is formed by depositing a silicon core on a silica substrate. Whereas the slot waveguide is tailored by keeping a narrow air gap between two silicon strip waveguides. Finally, the hybrid plasmonic waveguide is composed of Metal-Air-Silicon structure, where the E-field is significantly enhanced in the narrow air gap. The ring radius is kept at 1.5 μm for the three designs. The transmission spectrum and E-field distribution of these structures are simulated using the finite element method (FEM). Silicon strip waveguide-based ring resonators are easy to fabricate but their sensitivity is quite low as compared to the other two designs. μ-ring resonator based on hybrid plasmonic waveguide shows the best sensitivity of 333.3 nm/RIU. While, slot waveguide based μ-ring resonator showed the best performance in the quality factor, the figure of merits and limit of detection. We believe that this comparative study will facilitate the researchers to choose the suitable waveguide design for ring resonators depending on their preferred application and fabrication technology available.

Sensitivity Enhancement of Silicon Strip Waveguide Ring Resonator by Incorporating a Thin Metal Film

In this work, we proposed a metal-assisted silicon strip waveguide design for highly sensitive refractive index sensing applications. To prove the superiority of our proposed design, we make a fair comparison with the standard silicon strip waveguide of comparable geometry. In metal-assisted waveguide structure, a thin SiO2 layer is sandwiched between gold and silicon strip waveguide. The transmission spectrum and E-field distribution of these structures are simulated using 3D-Finite Element Method (FEM). In the first part of the paper, we demonstrated the enhancement of the evanescent field in the upper cladding region of a straight strip waveguide which makes it an ideal candidate for evanescent field gas absorption sensor. In the second part, we designed a metal-assisted silicon strip waveguide ring resonator of radius $1.5~\mu \text{m}$ and verified its higher sensitivity, Q-factor and figure of merit compared to standard ring resonator. The maximum sensitivity of 300 nm/RIU is obtained which is ~67% higher than the sensitivity of a standard ring resonator design when sandwiched SiO2 layer is equal to 50 nm in our proposed design. We believe that our study will provide new favourable circumstances to design sensors with improved sensitivity.

Voltammetric Determination of Arsenic with Modified Glassy Carbon Electrode

AbstractIn this study, glassy carbon electrode modified with nano gold‐crystal violet film has been used to detect arsenite (As (III)) in a model system and in groundwater samples. The modified electrode was characterized by scanning electrochemical microscopy (SECM) and electrochemical impedance spectroscopy (EIS). Using voltammetric measuring technique, linear response was obtained in a concentration range of 2.0–22.0 μM. The arsenite concentrations in groundwater samples varied between 2.4 μM to 4.8 μM. The sensitivity of the modified electrode for As (III) detection was 5.6 μA/μM cm2 and 0.8 μM concentration was found as lower limit of detection (LOD). The accuracy of the method was checked with standard method anodic stripping voltammetry (ASV). Groundwater samples were characterized with dynamic (DLS) and electrophoretic (ELS) light scattering measurements which have shown that particles present in different samples differ in size distribution and zeta potential which did not interfere with As (III) detection.

An Adaptive GaoFen-3 SAR Wind Field Retrieval Algorithm Based on Information Entropy

Chinese GaoFen-3 (GF-3) synthetic aperture radar (SAR) imagery acquired in standard strip mode can capture streak features caused by wind over the sea surface, which are commonly known as wind streaks. To retrieve the sea surface wind field from a GF-3 SAR image, an adaptive wind retrieval algorithm based on information entropy is proposed in this paper. This algorithm can adaptively extract the optimal wavenumber range of each subimage based on maximum information entropy. After all subimages are processed for possible wind streak direction solutions, a circle median filter is used to determine the unique wind streak direction solution for each subimage. Twelve GF-3 standard strip SAR images are inverted to validate the proposed algorithm. The experiments show that when the GF-3 image data are compared to the European Centre for Medium-Range Weather Forecasts reanalysis wind field data, the root mean square error of wind speed and direction retrieved by the algorithm are 1.29 m/s and 15.33°, respectively, and when they are compared to the National Data Buoy Center buoy wind data, the mean absolute deviation errors of wind speed and direction are 0.57 m/s and 9.95°, respectively. These comparisons demonstrate that the proposed algorithm can effectively retrieve wind field information from GF-3 SAR images.

The effect of fennel seeds on pH of saliva - A clinical study.

Saliva is an oral fluid that gives a protective effect against dental caries. Chewing of fennel seeds after food is a common culture in the Indian Sub-continent. A review of previous studies on fennel seeds showed that some of them have an anti-microbial efficacy, but there are no extensive data available on the effect of chewing fennel seeds on the pH of saliva. The aim of the study was to record the baseline pH of saliva and to record the changes in salivary pH after chewing fennel seeds. The study was carried out in the Department of Public Health Dentistry, Sri Ramachandra University, Chennai, prior to which a pilot study was carried out. Voluntary enrolment of 30 individuals was done. A written and informed consent was obtained from the individuals prior to the study. The pH of the saliva was recorded by placing the standardized salivary strip below the tongue in the oral cavity and colour changes were matched with the pH scale colour chart within about 15 sec. The subjects were asked to chew fennel seeds for 5 min. Salivary pH was measured immediately after chewing (SP2) at 0 min and the experiment was repeated for 5 min (SP3), 10 min (SP4), 15 min (SP5) and 30 min (SP6). The data was gathered and analysed using paired t test. There was an increase in salivary pH from baseline (SP1) to 0 min (SP2) was found to be highly significant (P = 0.000). The mean salivary pH reduced to 7.64 ± 0.06, 5 min after chewing the seeds (SP3) and the drop in pH was found to be highly significant (P = 0.000). The subsequent drop in pH from 10 min (SP4), 7.50 ± 0.05 to 15 min (SP4), 7.38 ± 0.05 to 30 min (SP4), 7.24 ± 0.05 were found to be highly significant as well (P = 0.000). Chewing of fennel seeds increases the pH of saliva, thus making it a suitable anti-cariogenic agent.

Development and research of the cultivator frame design made of non-standard beams

The paper presents the results of the development and study of the strength of the cultivator frame made of non-standard beams. The term “non-standard beam” refers to a off-sized beam welded from steel strips. As such stripes, both standard hot-rolled strips and strips cut from standard cold-rolled or hot-rolled sheets can be used. The main advantage of the proposed frame design is the relatively low cost and availability of materials for its manufacture, as well as the potential to minimize the weight of the finished product by changing the thickness and dimensions of the strips used. Frame design and calculations were performed by the Autodesk Inventor Professional environment.