A new silica-gel nanospheres (SiO2NPs) composition was formulated, followed by biochemical surface functionalization to examine its potential in urea biosensor development. The SiO2NPs were basically ...synthesized based on sol-gel chemistry using a modified Stober method. The SiO2NPs surfaces were modified with amine (-NH2) functional groups for urease immobilization in the presence of glutaric acid (GA) cross-linker. The chromoionophore pH-sensitive dye ETH 5294 was physically adsorbed on the functionalized SiO2NPs as pH transducer. The immobilized urease determined urea concentration reflectometrically based on the colour change of the immobilized chromoionophore as a result of the enzymatic hydrolysis of urea. The pH changes on the biosensor due to the catalytic enzyme reaction of immobilized urease were found to correlate with the urea concentrations over a linear response range of 50-500 mM (R2 = 0.96) with a detection limit of 10 mM urea. The biosensor response time was 9 min with reproducibility of less than 10% relative standard deviation (RSD). This optical urea biosensor did not show interferences by Na+, K+, Mg2+ and NH4+ ions. The biosensor performance has been validated using urine samples in comparison with a non-enzymatic method based on the use of p-dimethylaminobenzaldehyde (DMAB) reagent and demonstrated a good correlation between the two different methods (R2 = 0.996 and regression slope of 1.0307). The SiO2NPs-based reflectometric urea biosensor showed improved dynamic linear response range when compared to other nanoparticle-based optical urea biosensors.
Many of the hard tissue implants are made of titanium alloys, due to its low specific strength and low elastic modulus with excellent biocompatibility and good corrosion resistance. The difference in ...elastic modulus between cortical bone and titanium alloy leads to stress shielding which leads to bone fracture. To avoid this, there is a need of reduction in elastic modulus of available titanium alloy implant with an adequate strength to withstand the applied load. Here three different machine learning techniques, viz. multiple linear regression analysis, artificial neural network and fuzzy inference systems, are employed for designing titanium alloy for biomedical application having lower modulus with adequate strength. The purpose of the work is to find the role of alloying elements and processing parameters in determining the two mechanical properties, so that the alloy can be properly designed to achieve the targeted performance. There were discrepancies between the results generated by different tools. But it was found that alloying elements like Al, Zr, Fe, Sn and Cr play the most significant role in reducing the modulus of elasticity without much compromise in the strength of titanium alloy.
The present work seeks to address the forced convection heat transfer behaviour of a double-pass solar air heater system (DPSAHS) provided with asymmetric channel flow configuration used for solar ...drying of agro-products. Outdoor experiments were performed on a DPSAHS having a constant channel depth ratio of 1.5. Thermal response of the DPSAHS under different influencing parameters such as flow rate, channel depth, and thermophysical properties of the working fluid was experimentally determined. The influence of ambient parameters such as solar intensity, ambient temperature, wind speed, and relative humidity on the thermodynamic behaviour of the DPSAHS was also investigated. Among which, solar intensity and ambient temperature were found to be the major parameters influencing the energy and exergy efficiency followed by wind speed. Relative humidity was found to have the least percentage contribution towards the thermal characteristics of the system. Overall thermal efficiency and exergy efficiency were found to vary in the range of 20–41% and 5.6–18% at two different mass flow rates of 0.02 kg s
−1
and 0.03 kg s
−1
, respectively. The results also inferred that the influence of thermophysical property variation on the thermodynamic performance depends upon the operating temperature range and on the nature of working fluid. Air temperature in the lower channel was found to be an average 3 °C higher than that of upper channel passage corresponding to two different mass flow rates. Hence, the thermodynamic behaviour of DPSAHS was found to be strongly influenced by the variation in channel depth, ambient parameters, and mass flow rate. The obtained experimental results were also compared with the available literatures.
CuO films deposited using precursors of different concentrations exhibit high absorption in the solar spectrum region (0.2–0.8μm), the reflection is very low and the reflectance in some region is ...near to 0%, while in the infrared region (0.8–2.5μm), the reflectance is rather high. This indicates that the CuO thin films have good solar selectivity.
Display omitted
•Nano structured semiconducting CuO thin film deposited by spray pyrolysis.•CuO mono phase formation was confirmed by the XRD, XPS and FT-Raman studies.•Films exhibited high absorption in the solar spectrum region (0.2–0.8μm) indicates good solar selectivity.•Low intense photoluminescence emission peaks revealed the light retaining capacity.
As major attention has been paid to solar cells with extremely thin absorber, present study embark on the structural, surface, optical and electrical characterization of spray deposited CuO absorber layers prepared using precursors of different concentrations at the constant substrate temperature of 350°C. Confirmed monoclinic lattice and the CuO vibrational modes implied the tenorite phase formation of CuO. Smooth surface and the uniform distribution of a surface grain which contains Cu2+ as the main oxidation state of the cations established the suitability of the CuO thin films as energy absorbers. Optical absorption in selective regions, estimated optical bandgap and low intense photoluminescence peaks favored respectively the easy charge transfer and the light retaining capacity of the CuO films. Probably, a combination of electrical conduction with nanostructured CuO will be helpful for future developments of substrates for solar cells with CuO as absorber layers.
•The DIAT-μ RadHAR dataset spanning a wide range of human suspicious actions is created.•An indigenously developed X-band CW radar is employed in this work to build the diversified DIAT-μ RadHAR ...dataset.•The Performance of the DCNN models are tested in open-field trials.
The non-availability of open-source datasets covering various human suspicious activities and well-trained deep learning (DL) architecture limits the effective utilization of DL network-supported radar systems for real-time autonomous human activity recognition (HAR). The development of a dataset and validation of its micro-Doppler-signature-distinguishable-features by a suitable DL network becomes significant, and that is the key contribution given in this research. In this work, an indigenously developed X-band CW radar is employed to create a diverse DIAT-μ RadHAR dataset, which includes (a) army marching, (b) Stone pelting/Grenades throwing, (c) jumping with holding a gun, (d) army Jogging, (e) army crawling and (f) boxing activities. Six Pre-trained CNNs models supported DL architectures, trained with DIAT-μRadHAR dataset containing 3780 m-D images, are proposed, which can be used for open-field HAR. The characteristics of our dataset and performance analysis of the proposed two DL architectures are statistically computed, and their results are compared in terms of receiver operating characteristic (ROC), precision, F1-score, recall, and confusion matrix. The pre-trained VGG19 with transfer learning outperforms other CNNs with an overall classification accuracy of 98%.
We report theoretical and experimental investigations of flow through compliant microchannels in which one of the walls is a thin PDMS membrane. A theoretical model is derived that provides an ...insight into the physics of the coupled fluid–structure interaction. For a fixed channel size, flow rate and fluid viscosity, a compliance parameter
f
p
is identified, which controls the pressure–flow characteristics. The pressure and deflection profiles and pressure–flow characteristics of the compliant microchannels are predicted using the model and compared with experimental data, which show good agreement. The pressure–flow characteristics of the compliant microchannel are compared with that obtained for an identical conventional (rigid) microchannel. For a fixed channel size and flow rate, the effect of fluid viscosity and compliance parameter
f
p
on the pressure drop is predicted using the theoretical model, which successfully confront experimental data. The pressure–flow characteristics of a non-Newtonian fluid (0.1 % polyethylene oxide solution) through the compliant and conventional (rigid) microchannels are experimentally measured and compared. The results reveal that for a given change in the flow rate, the corresponding modification in the viscosity due to the shear thinning effect determines the change in the pressure drop in such microchannels.
Chronic cough is a common condition that presents to both primary and secondary care. Assessment and management are hampered by the absence of well-validated outcome measures. The present study ...comprises the validation of the Leicester Cough Monitor (LCM), an automated sound-based ambulatory cough monitor. Cough frequency was measured with the LCM and compared with coughs and other sounds counted manually over 2 h of a 6-h recording by two observers in nine patients with chronic cough in order to determine the sensitivity and specificity of the LCM. Automated cough frequency was also compared with manual counts from one observer in 15 patients with chronic cough and eight healthy subjects. All subjects underwent 6-h recordings. A subgroup consisting of six control and five patients with stable chronic cough underwent repeat automated measurements > or = 3 months apart. A further 50 patients with chronic cough underwent 24-h automated cough monitoring. The LCM had a sensitivity and specificity of 91 and 99%, respectively, for detecting cough and a false-positive rate of 2.5 events x h(-1). Mean+/-SEM automated cough counts x patient x h(-1) was 48+/-9 in patients with chronic cough and 2+/-1 in the control group (mean difference 46 counts x patient x h(-1); 95% confidence interval (CI) 20-71). The automated cough counts were repeatable (intra-subject SD 11.4 coughs x patient x h(-1); intra-class correlation coefficient 0.9). The cough frequency in patients undergoing 24-h automated monitoring was 19 coughs x patient x h(-1); daytime (08:00-22:00 h) cough frequency was significantly greater than overnight cough frequency (25 versus 10 coughs x patient x h(-1); mean difference 15 coughs x patient x h(-1), 95% CI 8-22). The Leicester Cough Monitor is a valid and reliable tool that can be used to assess 24-h cough frequency in patients with cough. It should be a useful tool to assess patients with cough in clinical trials and longitudinal studies.
Display omitted
•Design and construction of n-FeTiO2/p-Si diode.•Higher order crystallinity with orthorhombic structure.•Tuned Optical band gap of 3.11 eV.•Diode characteristics with barrier height ...(Φb) value of 0.43 eV in dark and 0.65 eV under light.
FeTiO2 thin films are prepared by sol–gel dip coating technique at room temperature. The X-ray Diffraction (XRD) analysis confirms the good crystalline nature of the prepared thin films and the UV–Vis Spectroscopic results revealed an optical band gap value around 3.11 eV. The electrical property from I-V represented an increase in electric field with corresponding increase in current density. The prepared thin films are used in the construction of P-N junction diode. The design and construction of the P-N junction diode has been elaborated here. The diode performance has been studied through the voltage Vs current characteristic graphs. The diode parameters of ideality factor (n) and barrier height (Φb) of n-FeTiO2/p-Si is calculated from the I-V measurements in darkness and under the illumination using J-V method. The value of ideality factor n for n-FeTiO2/p-Si diode is 6.88 in dark but under light, it increases to 7.51.
PDF
