Thermally activated shape memory behavior of melt‐mixed polyurethane/cellulose nanocrystal composites

Building blocks made from renewable sources attract increasing attention for the design of new polymer systems. Recently, in this particular context, cellulose nanocrystals (CNCs) have gained great interest in both academic research and industry, mainly on account of their ability to reinforce range of polymer matrices and afford nanocomposites with attractive mechanical properties. The limited thermal stability of conventionally produced cellulose nanocrystals (CNCs) has, however, so far limited the range of polymers that could be used as basis for melt‐processed CNC nanocomposites. We herein show that a commercially accessible nanocrystal source, a particular grade of microcrystalline cellulose (MCC), can easily be converted into thermally stable CNCs by ultrasonication in phosphoric acid. A scalable melt‐mixing process was used to produce nanocomposites of these CNCs with a thermoplastic polyurethane (TPU) elastomer. A significant improvement of the room temperature storage modulus from 40 MPa (neat polymer) to 120 MPa (10% w/w CNC) was observed. The introduction of CNCs not only increased the stiffness of the polymer matrix, but also improved the shape memory properties of the nanocomposite. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45033.     

Evaluation of Ku‐band QuikSCAT scatterometer data for rice crop growth stage assessment

A study has been carried out to analyse the high temporal Ku‐band scatterometer data from QuikSCAT with 4.45 km resolution for regional assessment of rice crop phenology. Four‐day composite data were used covering the two predominant rice‐growing states in India during the monsoon season of 2004. These data were registered with reference to a rice map derived from RADARSAT SAR data of the same season in order to select predominant rice sites. Analysis shows the dual peak backscatter profile of rice crop (at tillering stage and another at maturity). Minima of the backscatter profile were found to coincide with the heading. The derived heading stage using a lognormal curve fitting matched well with the observed dates. The slope of the second peak varied with crop variety, and shows the potential of correlation with the panicle characteristic.     

Machine learning based quality evaluation of mono-colored apples

In the field of agriculture science, automatic visual inspection improves the commercial, quality and fertility of the country. It is very challenging to sort the fruit based on quality because of varieties of fruits available in the market. Human grades the fruit but it is inconsistent, stagnant, and expensive and influenced by the surrounding. Thus an effective system for grading of fruit is desired. In this paper, an automated fruit grading system is developed for apple to classify based on external quality. The different combination of several features are considered depending on the damages exposed on apple fruits. In this work, these features are considered as input to train Support Vector Machine (SVM). The classifier has been contemplated with two different database of apple: one having 100 color images out of which 24 are of apples with various defects and the other dataset having 112 color images out of which 56 are of apples with various defects. The system performance has been validated using k-fold cross validation technique by considering different values of k. The maximum accuracy 96.81% and 93.00% for two dataset respectively, achieved by the system is encouraging and is comparable with the state of art techniques.

     

Sulfonated co-poly(ether imide)s with alkyne groups: Fabrication of crosslinked membranes and studies on PEM properties including MFC performance

A new diamine monomer having alkyne side-groups (DADAF) has been successfully synthesized, and it was used to prepare a series of sulfonated co-polyimides (DFN-XX) when reacted with 1,4,5,8-naphthalenetetracarboxylic dianhydride along with different mole% of 4,4′-diaminostilbene-2,2′-disulfonic acid. The membrane was made from the copolymers by solution casting route, and one of the copolymers DFN-70 was used to prepare crosslinked membranes by adding a different amount of 1,6-hexanediazide during solution casting step. The morphological transformation from non-crosslinked S-coPI to crosslinked S-coPI was observed by employing transmission electron microscopy, atomic force microscopy, and small-angle X-ray scattering analyses. Compared to the non-crosslinked DFN-XX membranes, crosslinked DFN-70 copolymer membranes showed low water uptake and improved mechanical and peroxide radical stability. Also, crosslinked DFN-70 copolymer membranes showed significantly higher proton conductivities (0.004-0.06 S cm⁻¹) compared to those of DFN-70 (0.003-0.05 S cm⁻¹) particularly, at 80°C when the relative humidity increased from 40% to 98%. Furthermore, crosslinked DFN-70 copolymer membranes exhibited significantly enhanced performance in a microbial fuel cell (MFC) as compared to those of non-crosslinked DFN-70 membrane.     

Variations of Slot Cut and Stub Loaded Square Microstrip Antenna for Circular Polarization

Wireless Personal Communications - Modified technique to produce circular polarization for square, nearly square microstrip antenna using diagonal slots of different shapes, slits, stub at corners...     

Effect of complexing agents: investigations on structural,morphological, topographical and optical analysis of copper iron sulphide thin films deposited by chemical bath deposition method

Copper iron sulphide (FeCuS₂) thin films deposited by chemical bath deposition method using ferrous sulphate and copper sulphate as cationic sources and sodium sulphide as anionic source with complexing agents, EDTA and Leishman stain were reported. The structural, optical and morphological studies were carried out using X-ray diffraction, scanning electron microscopy (SEM), atomic force microscopy (AFM) and UV–Visible spectroscopy techniques. The X-ray spectrum reveals that the films are polycrystalline nature and also showed the deposition of cubic phases at room temperature. The SEM images for prepared films have clear morphology influenced by the complexing agents used in deposition process. The result of AFM studies shown that the particles in the film have grain size around ~?60–70 nm and also have almost similar thickness. Based on the optical absorbance spectra the FeCuS₂ film exhibited a high absorbance in the visible region. The absorption edge shifted toward lower wavelength with varying complexing agents. The band gap value obtained was found to be 3.57–3.85 eV. From these results, it is indicated that the prepared films are suitable candidate for solar cell applications.     

Facing the reality of data stream classification: coping with scarcity of labeled data

Recent approaches for classifying data streams are mostly based on supervised learning algorithms, which can only be trained with labeled data. Manual labeling of data is both costly and time consuming. Therefore, in a real streaming environment where large volumes of data appear at a high speed, only a small fraction of the data can be labeled. Thus, only a limited number of instances will be available for training and updating the classification models, leading to poorly trained classifiers. We apply a novel technique to overcome this problem by utilizing both unlabeled and labeled instances to train and update the classification model. Each classification model is built as a collection of micro-clusters using semi-supervised clustering, and an ensemble of these models is used to classify unlabeled data. Empirical evaluation of both synthetic and real data reveals that our approach outperforms state-of-the-art stream classification algorithms that use ten times more labeled data than our approach.     

The Renin–Angiotensin-Aldosterone System,Nitric Oxide,and Hydrogen Sulfide at the Crossroads of Hypertension and COVID-19: Racial Disparities and Outcomes

Coronavirus disease 2019 is caused by SARS-CoV-2 and is more severe in the elderly, racial minorities, and those with comorbidities such as hypertension and diabetes. These pathologies are often controlled with medications involving the renin–angiotensin–aldosterone system (RAAS). RAAS is an endocrine system involved in maintaining blood pressure and blood volume through components of the system. SARS-CoV-2 enters the cells through ACE2, a membrane-bound protein related to RAAS. Therefore, the use of RAAS inhibitors could worsen the severity of COVID-19’s symptoms, especially amongst those with pre-existing comorbidities. Although a vaccine is currently available to prevent and reduce the symptom severity of COVID-19, other options, such as nitric oxide and hydrogen sulfide, may also have utility to prevent and treat this virus.     

Silver-doped titanium dioxide nanoparticles encapsulated in chitosan–PVA film for synergistic antimicrobial activity

The objective of the present study performed was to develop and characterize of silver (Ag)-doped titanium dioxide (TiO₂) naoparticles (NPs) encapsulated in chitosan–polyvinyl alcohol (PVA) film for synergistic antimicrobial activity. The acidic solution of chitosan with PVA was used for the reduction of silver ions into silver NPs using their functional groups such as hydroxyl, carboxyl, and amino groups. The chitosan–PVA silver nanoparticle films showed significant antimicrobial and antifungal activity against Staphylococcus aureus, Candida albicans, and Pseudomonas aeruginosa. Therefore, the present study is an alternative for conventional treatment as antimicrobial film showed synergistic, noninvasive, and economic effects.