A REVIEW ON THE PURSUIT OF AN OPTIMAL MICROWAVE ABSORBER

Mitigation of the electromagnetic radiations is essential for reliable communication of information. The challenges lie in achieving sufficiently good absorption over a broad range of frequencies. Considering the applications in airborne and handheld devices where light weight, thin, conformable and broadband absorbers are desired, numerous techniques and methods are applied to design broadband absorbers. In this review paper, a detailed analysis on electromagnetic absorbers including evolution, the materials used, and characteristics such as absorption efficiency over the years is presented. Progress on recent research on various polymer- based and metamaterial- based microwave shields are included along with their findings. Several prospects such as broadbanding, flexibility, multibanding are described here. Various material and structural composition offering good absorption performance in different frequency bands are also summarized whose the techniques can be used for suppressing electromagnetic interference and radar signature. The paper specifies the aspects one encounters while designing and realizing a perfect microwave absorber. Explored here are several works of distinguished authors  which are based on various techniques used to achieve good absorption performance with ease of mounting

Ordinal to Cardinal positional transformation of need hierarchy

The drive to get an action accomplished is motivation. The combination of needs, drives and outcomes gets the action to move and this consolidated action is called motivation. Motivation helps judge the attractiveness of a stimulus. The knowledge of the determinants of motivation is very important for the study of motivation. The study of motivation reaches its proper significance when the works of Abraham Maslow is studied. The theory of needs answers variety of questions when motivation is to be studied. The significance of need accomplishment according to the hierarchy ladder of need as propounded by Maslow when studied in connection with consumer’s want for buying a house under the parameters of ordinal scale, receives a new paradigm when converted to the cardinal scale. The present research paper studies the consumer motivation factors according to the categories of consumers based on demography and converts the data from ordinal form to cardinal form. The conversion of data type helps the understanding and study of the data better. Where constituents of the respondent type unwrap the need hierarchy and carry the study of motivation to an elevated level

Chitosan Curcumin Film As A Sensor For Detection of O-Nitrophenol and Fluoride Ion Using Fluoresce Quenching Technique

Curcumin was immobilized in chitosan films fabricated by solvent casting method. The amount of curcumin immobilization was more when methanol was used as a solvent to dissolve curcumin than the butanol solvent. The maximum amount of curcumin immobilized per gram of chitosan film was 0.023 g. Immobilized curcumin was not released back in water even after prolong contact of the films with water. Fluorescence intensity of the films got quenched when these films were in contact with an aqueous solution of o-nitrophenol (ONP) and sodium fluoride (NaF). The extent of quenching depended on the concentration of these attributes. Fluorescence intensity was highly pronounced even when the concentration of ONP and fluoride (FL) was as low as 2.0 x 10–6 M and 2.5 x 10–5 M, respectively. UV-vis spectroscopy could not detect 2.5 x 10–6 M ONP; similarly, ion chromatography was not sensitive towards 2.5 x 10–5 M FL. Since the extent of quenching varies linearly with the concentration of ONP and FL in aqueous solution, the Stern-Volmer equation can be used for quantification of these

Kinematická analýza rytmických pohybů: aplikace na třes rukou člověka a kmit křídel mušky octomilky.

Rytmický pohyb, pravidelný nebo nepravidelný, je nedílnou součástí motorického chování a to jak ve zdraví, tak v průběhu nemoci. Hlubší pochopení geneze rytmického pohybu je důležité pro porozumění patofyziologii onemocnění, mezi jejichž projevy rytmický pohyb patří. V disertační práci jsem studovala dva konkrétní aspekty rytmického pohybu: bilaterální koordinaci a modulární řízení. První z nich jsem analyzovala na třesu lidských rukou, druhý na pohybu křídel u modelového organismu Drosophila melanogaster (octomilka obecná). Mnoho typů třesu, včetně fyziologického třesu (PT) a esenciálního tremoru (ET), se vyskytuje v končetinách po obou stranách těla, s podobnou základní frekvencí kmitání. To naznačuje, že kontralaterální třesy mohou mít společný zdroj nebo jsou jinak spojené. Ve své studii jsem prozkoumala vazbu mezi třesem levé a pravé ruky. Pomocí 3D- akcelerometrů jsem změřila časový průběh třesu, a použila stacionární i nestacionární (waveletové) výpočetní metody k vyhodnocení bilaterální koherence. Měření na všech třech prostorových osách umožnilo prozkoumat ucelenější sadu kinematických proměnných, než ve většině předešlých studií. Nestacionární analýza usnadnila identifikaci časově transientní koherence, což je scénář, který se v analýze třesu dříve nebral v úvahu. U většiny subjektů s PT...Rhythmic motions, regular or irregular, are an integral part of motor behavior both in health and in disease. Better understanding of its neural control mechanisms helps in developing methods for controlling the progression of diseases manifesting as rhythmic motions. I studied two specific aspects of rhythmic motions: bilateral coordination of hand tremors in human subjects and modular control of locomotion in invertebrates. Many types of tremors, including the physiological tremor (PT) and the essential tremor (ET) occur in limbs on both the sides of the body, with similar fundamental frequency of the oscillation. This raises the possibility that the contralateral tremors may have a common source or are otherwise coupled. However, while significant contralateral interaction is seen in these two types of tremors, only limited evidence of bilateral coherence has been shown in the previous literature. Therefore, in my study I explored the existence of a weak coupling between the left and right oscillators the may lead to intermittent bilateral coherence. I measured triaxial acceleration of the two hands and systematically assessed their bilateral coherence, using both stationary and non-stationary (wavelet-based) analyses methods. Measuring all three axes allowed examination of a more complete set...Institute of Biophysics and Informatics First Faculty of Medicine Charles University in PragueÚstav biofyziky a informatiky 1. LF UK v PrazeFirst Faculty of Medicine1. lékařská fakult

Analysis of Learned Features and Framework for Potato Disease Detection

For applications like plant disease detection, usually, a model is trained on publicly available data and tested on field data. This means that the test data distribution is not the same as the training data distribution, which affects the classifier performance adversely. We handle this dataset shift by ensuring that the features are learned from disease spots in the leaf or healthy regions, as applicable. This is achieved using a faster Region-based convolutional neural network (RCNN) as one of the solutions and an attention-based network as the other. The average classification accuracies of these classifiers are approximately 95% while evaluated on the test set corresponding to their training dataset. These classifiers also performed equivalently, with an average score of 84% on a dataset not seen during the training phase.Comment: 15 pages, 8 figure

Bentonite Reinforced Chitosan Scaffold: Effect of Bentonite Exfoliation on Scaffold Properties

Chitosan is under investigation as biodegradable scaffolding material for tissue engineering. Crosslinked chitosan alone cannot form a self-supporting scaffold hence it needs reinforcement. The group reported fabrication of chitosan scaffolds reinforced by exfoliated and non-exfoliated bentonite and compared their properties. Scaffolds were fabricated by freeze-drying technique. Bentonite was exfoliated by allowing it to swell in water for a certain time interval. XRD profile showed that swelling reduced the crystallinity of bentonite. Both types of bentonite dispersed well in the chitosan matrix and imparted structural stability to the scaffolds. Scaffolds had interconnected pores, apparent porosity of scaffold with exfoliated bentonite was higher than of scaffold with unexfoliated bentonite. The scaffolds swelled almost 35% in 3 days without losing the structural integrity. The scaffolds could be compressed to 50% of their original height. Compression modulus of scaffold with exfoliated bentonite was higher than that of unexfoliated bentonite scaffold

Carbohydrate polymers as controlled release devices for pesticides

Controlled release technology addresses problems associated with excessive use of toxic agricultural chemicals. This paper reviews the studies on the use of carbohydrate polymers as controlled release matrices for pesticides. Alginates, starch and its derivatives, chitosan, carboxymethylcellulose and ethylcellulose are some of the natural polymers discussed in this review. The advantages and disadvantages of these polymeric systems as well as the factors that affect pesticide release are presented. A discussion on the polymers’ encapsulation efficiency and release profile is also included, which will aid future researchers in identifying the suitable formulation for controlled release of pesticides. Combination of two polymers, incorporation of sorbents into polymer matrices, and modification of polymer systems are some of the strategies also discussed herein. Recent trends in this area of research include nanoformulation, nanoencapsulation, and the development of polymeric systems with dual properties such as controlled release with photo-protective property and the attract-and-kill strategy. Cytotoxicity studies are being conducted to address safety issues of pesticide handlers as well as to determine the toxicity of the formulation to non-target organisms such as the plant itself

Biocatalytic Synthesis of Diethanolamide Surfactants Under Mild Reaction Conditions

Synthesis of fatty acid diethanolamide was carried out by the condensation of diethanolamine with lauric acid, decanoic acid and octanoic acid in the presence of Novozym 435. The influence of solvent, time, temperature and agitation on the reaction rate was studied. Formation of lauroyl diethanolamide was complete in 6h in acetonitrile at 50° C whereas in toluene the reaction was not complete in 6h. Increase of reaction temperature from 50° C to 70° C increased the reaction rate. Proper agitation of the reaction mixture enhanced the reaction rate. Reaction in solution appeared to be more efficient than the reaction in solvent free system. The surface active property of the fatty acid amides was studied by determining their critical micelles concentration. The critical micelle concentration of lauroyl diethanolamide, decanoyl diethanolamide and octanoyl diethanolamide were found to be 0.63mM, 1.10mM, 1.45mM respectively in deionized water. Micelles of lauroyl diethanolamide were less than 1µm in size