Etching of (0 0 0 1) habit faces and matched cleavages of flux grown strontium hexaferrite crystals

Results of etching (0 0 0 1) planes of flux grown strontium hexaferrite crystals in 85% H₃P0₄ at 120 °C and 37% HCl at 100 °C are presented. Fractography reveals one-to-one correspondence of cleavage patterns on the two matched (0 0 0 1) cleaved planes. Etch patterns including hexagonal, point-bottomed pits with smooth sloping planes, hexagonal but flat-bottomed pits, geometrically centred hexagonal pits with regularly spaced terracing, eccentric hexagonal pits with irregularly spaced terracing, a large flat-bottomed hexagonal pit with a smaller point-bottomed hexagonal pit within it but having different geometrical centres and flat-bottomed pits with a beak at their centres are illustrated. It is explained that they are indicative of normal, inclined, stepped and bending dislocations in strontium hexaferrite crystals. Pits due to impurity inclusions are also explained. The explanations are supported by the results of mismatchings of etch patterns on matched cleavages.     

The Role of Underutilized Fruits in Nutritional and Economic Security of Tribals: A Review

The tribal people of Rajasthan are severely malnourished along with multiple nutrient-deficiency disorders due to ignorance about importance of fruits and vegetables in their diets. The tribal areas are full of biodiversity having natural vegetation which is not harnessed fully. Due to which a wide gap is formed between health and optimal use of natural sources of nutrients, i.e., underutilized crops. The crops, which are neither grown commercially on large scale nor traded widely, may be termed as underutilized horticultural crops. These crops are cultivated, traded, and consumed locally. These crops have many advantages like easier to grow and hardy in nature, producing a crop even under adverse soil and climatic conditions. So, exploitation of underutilized horticultural crops can become a solution to the social problem of health and nutrition insecurity, poverty, and unemployment. The consumption of underutilized fruit crops can provide nutrition to the poor and needy tribals by meeting the nutrient requirements of vulnerable groups. As underutilized fruits, nuts, and vegetables are a rich of source of carbohydrates, fats, proteins, energy, vitamins—A, B₁, B₂, B₃, B₆, B₉, B₁₂, C, folic acid, and minerals—Ca, P_, Fe, and dietary fiber. Thus, they have the nutritional capacity to prevent and cure various diseases like kwashiorkor, marasmus, night blindness, anemia, diabetes, cancer, hypertension, and hidden hunger. It is also established fact that seasonal, locally available, and cheap fruits and vegetables can also keep the population healthy and nutritionally secure rather than costly off-season ones. Also, the underutilized crops have the potential to give economic security to tribals by giving employment and by fetching good returns from their sale in raw form as well as value-added products.     

THERMOSOLUTAL INSTABILITY OF A COMPRESSIBLE ROTATING WALTERS' (MODEL B′) ELASTICO-VISCOUS FLUID IN THE PRESENCE OF HALL CURRENTS

Effect of Hall currents is considered on Walters' (Model B′) elastico-viscous fluid heated and soluted from below in the presence of a vertical magnetic field. A dispersion relation governing the effects of viscoelasticity, salinity gradient, rotation, magnetic field, and Hall current is derived. For the case of stationary convection, the Walters' (Model B′) fluid behaves like an ordinary Newtonian fluid. The compressibility, stable solute gradient, rotation, and magnetic field postpone the onset of thermosolutal instability, whereas Hall currents are found to hasten the onset of thermosolutal instability in the absence of rotation. In the presence of rotation, Hall currents postpone/hasten the onset of instability depending upon the value of wave numbers as small/large. Again, the dispersion relation is analyzed numerically and the results depicted graphically. The viscoelasticity, solute gradient, and magnetic field (and corresponding Hall currents) introduce oscillatory modes in the system that were nonexistent in their absence. The case of over-stability is discussed and sufficient conditions for nonexistence of over-stability are derived.     

Wideband transimpedance amplifier using negative capacitance and capacitive feedback

This paper presents a microwave system for heartbeat rate measurement. This system is based on using a vector network analyzer and horn antennas. The system generates a continuous wave signal toward a person’s chest then the reflected signal is analyzed. The phase difference between the emitted and the reflected signals contains information about the chest movement; hence, the heartbeat rate can be extracted. In this work, several scenarios for detecting the heart activity are considered. The first scenario aims to provide a comparative study for using single-antenna and two-antennas microwave systems. Several radiated powers are considered in this scenario. Simultaneously with the microwave system, a wireless electrocardiograph is used as reference in order to determine the accuracy of the system. Measurements are performed in both cases when breathing normally and when holding the breath. The second scenario aims to test the ability of detecting the heartbeat activity of a person while moving. Measurements are performed while the subject walks towards the radar. Modeling is used for this purpose. The operating frequency used is 20 GHz in both scenarios. Signals are processed using wavelet transform and results show the ability to extract the heartbeat rate even with the presence of body movement.     

Chained Dual-Generative Adversarial Network: A Generalized Defense Against Adversarial Attacks

Neural networks play a significant role in the field of image classification. When an input image is modified by adversarial attacks, the changes are imperceptible to the human eye, but it still leads to misclassification of the images. Researchers have demonstrated these attacks to make production self-driving cars misclassify Stop Road signs as 45 Miles Per Hour (MPH) road signs and a turtle being misclassified as AK47. Three primary types of defense approaches exist which can safeguard against such attacks i.e., Gradient Masking, Robust Optimization, and Adversarial Example Detection. Very few approaches use Generative Adversarial Networks (GAN) for Defense against Adversarial Attacks. In this paper, we create a new approach to defend against adversarial attacks, dubbed Chained Dual-Generative Adversarial Network (CD-GAN) that tackles the defense against adversarial attacks by minimizing the perturbations of the adversarial image using iterative oversampling and undersampling using GANs. CD-GAN is created using two GANs, i.e., CDGAN’s Sub-Resolution GAN and CDGAN’s Super-Resolution GAN. The first is CDGAN’s Sub-Resolution GAN which takes the original resolution input image and oversamples it to generate a lower resolution neutralized image. The second is CDGAN’s Super-Resolution GAN which takes the output of the CDGAN’s Sub-Resolution and undersamples, it to generate the higher resolution image which removes any remaining perturbations. Chained Dual GAN is formed by chaining these two GANs together. Both of these GANs are trained independently. CDGAN’s Sub-Resolution GAN is trained using higher resolution adversarial images as inputs and lower resolution neutralized images as output image examples. Hence, this GAN downscales the image while removing adversarial attack noise. CDGAN’s Super-Resolution GAN is trained using lower resolution adversarial images as inputs and higher resolution neutralized images as output images. Because of this, it acts as an Upscaling GAN while removing the adversarial attak noise. Furthermore, CD-GAN has a modular design such that it can be pre-fixed to any existing classifier without any retraining or extra effort, and can defend any classifier model against adversarial attack. In this way, it is a Generalized Defense against adversarial attacks, capable of defending any classifier model against any attacks. This enables the user to directly integrate CD-GAN with an existing production deployed classifier smoothly. CD-GAN iteratively removes the adversarial noise using a multi-step approach in a modular approach. It performs comparably to the state of the arts with mean accuracy of 33.67 while using minimal compute resources in training.     

Brilliant Cresyl Blue – Fructose for enhancement of solar energy conversion and storage capacity of photogalvanic solar cells

The Brilliant Cresyl Blue dye as photosensitizer, Fructose as reductant and NaOH as alkaline medium have been studied for enhancing the solar energy conversion and storage capacity of the photogalvanic solar cells. In this study, the observed values of electrical parameters like maximum potential, maximum photocurrent, short-circuit current, power at power point, and conversion efficiency are 1115 mV, 785 μA, 590 μA, 183.3 μW, and 1.9586%, respectively. In dark, the cell performance in terms of storage capacity (as half change time) was 228 min. The obtained results are highly encouraging as they are radically higher than results reported so far in the field of photogalvanics. We conclude that Brilliant Cresyl Blue – Fructose system significantly enhances the performance of the photogalvanic solar cells and this system may be the basis for further advancement of this technology.     

Validation of pressure drop prediction and bed generation of fixed-beds with complex particle shapes using discrete element method and computational fluid dynamics

Catalytic fixed-bed reactors with a low tube-to-particle diameter ratio are widely used in industrial applications. The heterogeneous packing morphology in this reactor type causes local flow phenomena that significantly affect the reactor performance. Particle-resolved computational fluid dynamics has become a predictive numerical method to analyze the flow, temperature, and species field, as well as local reaction rates spatially and may, therefore, be used as a design tool to develop new improved catalyst shapes. Most validation studies which have been presented in the past were limited to simple particle shapes. More complex catalyst shapes are supposed to increase the reactor performance. A workflow for the simulation of fixed-bed reactors filled with various industrially relevant complex particle shapes is presented and validated against experimental data in terms of bed voidage and pressure drop. Industrially relevant loading strategies are numerically replicated and their impact on particle orientation and bed voidage is investigated.     

Interpretation of Association Behavior and Molecular Interactions in Binary Mixtures from Thermoacoustics and Molecular Compression Data

Density and acoustic velocity were measured for binary liquid mixtures of formamide, N-methylacetamide (NMA), dimethylformamide (DMF), and dimethylacetamide (DMA) with acetonitrile at atmospheric pressure and 293.15 K, 298.15 K, 303.15 K, 308.15 K, or 313.15 K over the concentration range 0.12 to 0.97. Models assuming association and nonassociation of the components of the mixtures were used to predict the behavior of the studied liquids, which would typically show weak interactions. The measured properties were fitted to the Redlich–Kister polynomial to estimate the binary coefficients and standard errors. The data were used to study the molecular interactions in the binary mixtures. Furthermore, the McAllister multibody interaction model was used to correlate the properties of the binary liquid mixtures. Testing of the nonassociation and association models for the different systems showed that, compared with the nonassociation model theoretical results, the association model theoretical results were more consistent with the experimental results.