Undoped and nitrogen-doped ZnO (NZO) thin films were deposited by sol–gel spin-coating technique on glass substrates. The thin film preparation was accomplished using zinc acetate dihydrate, ...monoethanolamine and 2-methoxyethanol as the precursors. Ammonium acetate was used as the source of nitrogen for doping. The effect of dopants and the post-heating temperature on the various physical properties of the deposited films was explored. The X-ray diffraction studies reveal the polycrystalline nature of the films which possess a preferred
c
-axis orientation. Raman characterizations of the films show a clear indication of nitrogen incorporation in the films. The carrier concentration of the thin films was of the order of 10
17
/cm
3
and resistivity as minimum as 0.371 Ω cm was observed for 1 at.% NZO thin films post-heated at 500 °C. The 1 at.% and 2 at.% doped NZO films post-heated at 300 °C and 1 at.%, 2 at.% and 3 at.% doped NZO films with post-heat treatment at 500 °C exhibited p-type conductivity. In the aging study, 500 °C annealed films retained p-type conductivity for 5 days.
The influence of self-immobilization of enriched acidogenic mixed consortia on fermentative hydrogen (H
2) production was studied on different supporting materials SBA-15 (mesoporous) and activated ...carbon (granular; GAC and powder; PAC) using chemical wastewater as substrate. Batch fermentation experiments were performed with same substrate at different organic loading rates (OLRs) under acidophilic microenvironment (pH 5.5) and room temperature (28
±
2
°C). Experimental data evidenced the effectiveness of attached growth on both the H
2 yields and substrate degradation efficiency, particularly at higher loading rates. Among the three materials evaluated, immobilization on SBA-15 material showed comparatively effective performance in enhancing both H
2 yield and substrate degradation. Suspended growth (SG-control) culture showed inhibition in terms of both H
2 production and substrate degradation especially at applied higher loading rates. Immobilization on SBA-15 resulted in nine times higher H
2 production (7.29
mol/kg
COD
R-day at OLR of 0.83
kg
COD/m
3-day) than the lowest yield observed (suspended growth at OLR of 2.55
kg COD/m
3-day). Maximum substrate degradation rate (SDR) of 0.96
kg
COD/m
3-day (OLR 2.55
kg
COD/m
3-day) was also observed with SBA-15 immobilization, which is 1.62 times higher than the lowest substrate degradation observed with SG-control experiments with the same OLR. Attached growth on GAC and PAC also showed remarkable improvement in the process performance at higher OLRs compared to SG-control.
Recent advances in woundcare is targeted towards developing active-dressings, where multiple components are combined to provide a suitable environment for rapid healing. The aim of the present ...research is to study the preparation of biomimic composite wound dressings by the grafting of hydrogel on silk fibroin fabric. The swelling ability of hydrogel grafted silk fibroin fabric was optimized by changing the initiator concentration. In order to impart antimicrobial properties, these dressing are further coated sono-chemically with zinc oxide nanoparticles. The water vapor transmission rate of the prepared samples was measured. The conformation of silk fibroin proteins after grafting with hydrogel was also confirmed using Fourier Transform Infrared Spectroscopy (FTIR). The morphology of the zinc oxide-coated silk fibroin fabric and hydrogel-coated silk fibroin was studied using Scanning Electron Microscope (SEM). The antimicrobial activity of the zinc oxide-coated samples was studied against
. The cytocompatibility of the prepared dressing materials were evaluated using L929 fibroblast cells. MTT assay and phase contrast microscopic studies showed that the adherence, growth, and proliferation of the L929 fibroblast cells that were seeded on zinc oxide nanoparticles on the functionalized hydrogel-coated silk fibroin dressing was significantly higher than that of pure silk fibroin due to the highly porous, bio-mimic structure that allowed ease of passage of nutrients, growth factors, metabolites, and the exchange of gases which is beneficial for successful regeneration of damaged tissues. The expression of TNF-α and IL-2 were not significantly higher than that of control. The proposed composite dressing would be a promising material for wound dressing and regenerative medicine but in order to prove the efficacy of these materials, more in vivo experiments and clinical tests are required to be conducted in future.
PurposeThe circular economy is a production and consumption model that encourages people to share, lease, reuse, repair, refurbish and recycle existing materials and products for as long as possible. ...The blockchain-based circular economy is being used in many industries worldwide, but Indian electronic MSMEs face many problems in adopting a blockchain-based circular economy. The research aims to discover the barriers the electronic MSMEs face in adopting a blockchain-based circular economy and pull back from achieving environmental sustainability in their operations.Design/methodology/approachFifteen barriers are identified from the literature review and finalized with experts' opinions. These barriers are evaluated by using interpretive structural modeling (ISM), MICMAC analysis and fuzzy TOPSIS method.FindingsLack of support from distribution channels, lack of traceability mechanism and customer attitudes toward purchasing remanufactured goods are identified as the most critical barriers.Practical implicationsThe study will benchmark the electronic MSMEs in achieving environmental sustainability in the blockchain-based circular economy.Originality/valueIt is a study that not only establishes a hierarchical relationship among the barriers of blockchain adoption in Indian electronic MSMEs but also verifies the results with fuzzy TOPSIS method.
Two catalysts, Ni/SBA-15 and Ni/MgO were prepared by wet impregnation technique with 5
wt.% Ni loading in each catalyst. These were tested for nitrobenzene hydrogenation to aniline reaction under ...vapor phase at atmospheric pressure. Ni/MgO suffered a huge loss in the activity (conversion) during time on stream study even though the Ni dispersion is larger compared to that in SBA-15 supported catalyst. TPR studies of used catalysts confirm coking of the catalysts. The superior catalytic activity in terms of conversion and selectivity during time on stream operation exhibited by Ni/SBA-15 catalyst is due to the hydrophobic nature of this catalyst (resistant to water generated during the reaction) and the effect of coking is not significant.
Hydrophobic nature of SBA-15 makes Ni/SBA-15 an ideal catalyst for nitrobenzene hydrogenation to aniline.
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► The hydrophobic nature of SBA-15 makes Ni/SBA-15 a robust catalyst. ► Deactivation of Ni/MgO is due to adsorption of water generated during the reaction. ► The role of carbon deposition during the reaction is insignificant on the activity. ► Strong interaction between Ni and MgO favors higher Ni dispersion.
Anemia is a condition that affects more than a billion people globally, with the highest prevalence noticed among women and children. In large parts of the world anemia is detected by using invasive ...laboratory techniques that require blood draw by trained doctors, nurses or laboratory staff. A low cost and easy to use noninvasive device that can be used at the doorstep or bedside of a patient has the potential to create a significant impact in anemia screening. In this paper, we present the architecture and development of such a device. Using a specific arrangement of light emitting diodes and fiber optics, we have created a novel multiwavelength spectrophotometry sensing platform to detect anemia. A mechanical lever operated fiber optics based sensor eliminates the problems associated with conventional noninvasive finger probe, aiding in the detection of hemoglobin levels as low as 1.6 g/dL. This study also proposes a method wherein incident light intensity can be measured along with attenuated light intensity to support hemoglobin estimation. The device could detect the light signals as low as 0.001% of the incident light intensity. Performance of the proposed platform was validated in conjunction with an algorithm to estimate hemoglobin. The device was able to estimate hemoglobin with an RMSE of 1.47 ± 0.042 g/Dl and a correlation of 0.79 ± 0.03 between the predicted and actual value of Hb.
We present a high performance self-powered photodetector fabricated using pure and rare earth (RE) doped titania on p-Si substrate. The structural study confirms the presence of major anatase phase ...for pure, Sm and Lu doped samples, while Nd doped sample showed mixed phase of anatase and brookite. A pin hole free, uniform nature of the surface was confirmed through morphological study. The I–V characteristics of the devices under dark condition were measured and diode parameters were extracted from Thermionic Emission and Cheung models. The devices under UV illumination confirmed the self-powered behaviour with high open circuit voltage and low short circuit current. The photodetector parameters like responsivity and detectivity were quantified to address the performance of the devices.
•RE (Nd, Sm & Lu) doped titania thin film/p-Si fabricated by spin coating method.•A high rectification ratio of about 103 is observed under dark.•Observed a high responsivity in the range between 0.037 and 0.528 A/W.•Appreciable self-powered mode is observed for RE doped devices.
Malfunction of internet networking systems might directly and the adverse effect in one way or the other, wherein aspects of contemporary information and communication technologies. In such ...conditions, DDoS attacks are prevalent threat, wherein flooding of requests related to computation and communication resources for ordering the service that is unavailable for legitimate users. DDOS attacks to be defend to guard the Critical resources. The contribution of this manuscript is an ensemble classifier model to defend the DDOS attacks. The Proposed model is based on ensemble classifier with drift detection ability at the service request stream level. The proposed model incorporates the process of defining service request streaming characteristics, enables the drift detection ability that uses the defined service request stream characteristics. The experimental study carried out from the setup established using synthesized service request stream, and the result obtained are explored using statistical metrics such as true negative rate, positive predictive value, accuracy. Moreover, the significance of the model elevated by comparing the obtained results with results obtained from other benchmark models depicted in contemporary literature.
In the present investigation, titania thin films doped with varying concentrations of Samarium (Sm) were synthesized by spin coating method on glass substrate. The obtained films were annealed at two ...different temperatures (350 and 450 ֯C) to induce crystallinity. The structural property of these samples was characterized by using X-ray Diffraction (XRD) and Raman spectrometer. The surface morphology of the films was analysed by Field Emission Scanning Electron Microscopy (FESEM) and Atomic Force Microscopy (AFM). The presence of pure anatase phase with enhanced polycrystalline nature was evident for the films annealed at 350 and 450 ֯C. Due to the addition of Sm, the titania thin films exhibited increased crystallinity. The Raman analysis also support the presence of crystalline anatase phase and the existence of defects in the deposited films. The prepared samples were also subjected to photocatalytic activity studies by using methyl orange (MO) dye and the results are discussed herein. The rate constant increased and half life time decreased considerably for 0.4 at% doped samples. The current work provides new ideas for monitoring the structural properties by adding low concentration rare earth dopant into metal oxides (titania) suitable for various applications.
Application layer based DDoS attacks have changed the way DoS attacks are taking place with more subtle level of attacking methods being imparted, which pose an ever-increasing challenge towards the ...emerging trends of internet based application systems development. Among the key range of attacks that take place, HTTP flood DDoS attacks are on high. In the case of DDoS attacks based on HTTP flood, unusual quantum of requests are sent to the servers within quick time interval and it affects the response and the performance levels of the server . There are numerous solutions in contemporary literature, pertaining to thwarting HTTP flood kind of attacks. It is imperative from the analysis that there are constraints in the existing models since the most of these models are user session based and/or packet flow patterns. The session based evolution models are vulnerable to botnets and packet flow pattern based models are vulnerable if attack sources are equipped with human resource and/or proxy servers. Hence, there is inherent need for improving the solutions towards addressing the HTTP flood kind of attacks over the system. The crux for such system is about ensuring that fast and early detection with minimal false alarming in streaming network transactions, and ensures that the genuine requests are not impacted. To address such a system, the model of Bio-Inspired Anomaly based HTTP-flood detection aimed, and the proposed model depicted in detail along with experimental inputs. Results attained from the process exemplify the significance and robustness of the model towards achieving the objectives considered for the solution.
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