Evaluating levy flight parameters for random searches in a 2D space

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2013.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pag 23).It is experimentally known that the flight lengths of random searches by foragers such as honey bees statistically belong to a power law distribution. Optimality of such random searches has been a topic of extensive research because knowing their optimal parameters may help applied sciences. Viswanathan et al. have shown the inverse-square power law to be the optimal law for such random searches. This thesis explores the capability of the model presented in such that it can be applied to Unmanned Autonomous Vehicles (UAVs). The thesis also identifies the minimum flight length, lmin, as an important factor that needs to be controlled based on the UAV's sensor range. We present a theoretical lmin as an explicit function of the sensor range, rv, and an estimated target density, p.by Mukul Kumar Singh.S.B

Photography and Its Relevance in Pathology

Pathology is a visual science which holds true of the old adage “seeing is believing.” Photography has become an integral part of this branch of medicine. Its application lies not only in diagnosis and consultation including telepathology, medicolegal documentation and quality assurance but also in learning and scientific purposes. The lower cost and shorter image production time has paved the way for digital imaging. Large archives of such images can be created and stored with an ease of access. Photography techniques in pathology are purely based on observation or experience rather than theory. This article aims to describe the practical aspects of photographic techniques in pathology

Seed yield and quality as influenced by growing conditions in hybrid seed production of bitter gourd (Momordica charantia L.) cv. Pusa Hybrid-1

The present investigation was carried out under insect proof net house (IPN) and open field condition (OFC) at Centre for Protected Cultivation Technology and Seed Testing Laboratory of Division of Seed Science &Technology, IARI, New Delhi in bitter gourd cv. Pusa Hybrid-1 during summer season because under open field condition the seed yield and seed quality of bitter gourd drastically reduced due to viral diseases and fruit fly in kharif and early onset of high temperature, unseasonal rains during summer, which restricts the hybrid seed production of bitter gourd under north Indian condition. The observations on seed yield & quality characters and physical properties of seed were recorded. The quality attributes were evaluated immediately after harvest and after 8 months of ambient storage and their results were compared. The experimental results revealed that total number of seed per fruit (46.7), number of filled seed per fruit (45.3), seed yield per fruit (9.41g), seed yield per plant (27.28g), and seed yield per hectare (232kg) were significantly higher under IPN in comparison to OFC. Among the physical parameters of seed, seed width (0.81cm) & seed coat (0.79g) weight recorded significantly higher in IPN. The seed quality attributes immediately after harvest was also significantly superior under IPN compared to OFC except for germination %. The hybrid seed produced under IPN conditions could maintain their superiority for quality traits even after 8 monthsof its ambient storage. The seed yield and seed quality attributes were comparatively superior under IPN conditions. The seed crop grown under IPN overcomes the threat of insect vectors, viral diseases and unfavourable climatic conditions and helps in attaining the better seed yield and quality

Synthetic and structural investigation of ZnO nano-rods, hydrothermally grown over Au coated optical fiber for evanescent field-based detection of aqueous ammonia

We present the fabrication of modified clad optical fiber coated with ZnO nanorod over Au thin film to be served as ammonia gas sensor. The deposited material ZnO synthesized by hydrothermal process and modified clad fiber is coated by Autoclave technique. The as-synthesized materials are characterized by XRD, XPS, FTIR, Raman spectra and its hexagonal nanorods morphology was checked by FESEM. The ZnO coated over Au thin film fiber is found to be a good candidate towards ammonia sensing. The developed sesnor exihibted sensitivity (%) ~ 0.638 of ammonia gas at room temperature

Bot Detection in Social Networks Based on Multilayered Deep Learning Approach

With the swift rise of social networking sites, they have now come to hold tremendous influence in the daily lives of millions around the globe. The value of one’s social media profile and its reach has soared highly. This has invited the use of fake accounts, spammers and bots to spread content favourable to those who control them. Thus, in this project we propose using a machine learning approach to identify bots and distinguish them from genuine users. This is achieved by compiling activity and profile information of users on Twitter and subsequently using natural language processing and supervised machine learning to achieve the objective classification. Finally, we compare and analyse the efficiency and accuracy of different learning models in order to ascertain the best performing bot detection system

Electronic structure of Pr2MnNiO6 from x-ray photoemission, absorption and density functional theory

The electronic structure of double perovskite Pr2MnNiO6 is studied using core x-ray photoelectron spectroscopy and x-ray absorption spectroscopy. The 2p x-ray absorption spectra show that Mn and Ni are in 2+ and 4+ states respectively. Using charge transfer multiplet analysis of Ni and Mn 2p XPS spectra, we find charge transfer energies {\Delta} of 3.5 and 2.5 eV for Ni and Mn respectively. The ground state of Ni2+ and Mn4+ reveal a higher d electron count of 8.21 and 3.38 respectively as compared to the atomic values of 8.00 and 3.00 respectively thereby indicating the covalent nature of the system. The O 1s edge absorption spectra reveal a band gap of 0.9 eV which is comparable to the value obtained from first principle calculations for U-J >= 2 eV. The density of states clearly reveal a strong p-d type charge transfer character of the system, with band gap proportional to average charge transfer energy of Ni2+ and Mn4+ ions.Comment: 18 pages, 9 figure

Strength assessment of PET composite prosthetic sockets

open access articleA prosthesis is loaded by forces and torques exerted by its wearer, the amputee, and should withstand instances of peak loads without failure. Traditionally, strong prosthetic sockets were made using a composite with variety of reinforcing fibres such as glass, carbon, and kevlar. Amputees in less- resourced nations can lack access to composite prosthetic sockets due to their unavailability or prohibitive cost. Therefore, this study investigates the feasibility of polyethylene terephthalate (PET) fibre-reinforced composites as a low-cost sustainable composite for producing functional lower-limb prosthetic sockets. Two types of these composites were manufactured using woven and knitted fabric with a vacuum assisted resin transfer moulding (VARTM) process. For direct comparison purposes, traditional prosthetic-socket materials were also manufactured from laminated composite (glass-fibre reinforced (GFRP)) and monolithic thermoplastic (polypropylene (PP) and high-density polyethylene (HDPE)) were also manufactured. Dog-bone-shaped specimens were cut from flat laminates and monolithic thermoplastic to evaluate their mechanical properties following ASTM standards. The mechanical properties of PET-woven and PET-knitted composites were found to be have been demonstrated to be considerably superior to those of traditional socket materials such as PP and HDPE. All the materials were also tested in the socket form using a bespoke test rig reproducing forefoot loading according to the ISO standard 10328. The static structural test of sockets revealed that all met the target load-bearing capacity of 125 kg. Like GFRP, the PETW and PETK sockets demonstrated higher deformation and stiffness resistance than their monolithic counterparts made from PP and HDPE. As a result, it was concluded that the PET-based composite could replace monolithic socket materials in producing durable and affordable prostheses

Origin of exchange bias in [Co/Pt]ML/Fe multilayer with orthogonal magnetic anisotropies

Magnetization reversal of soft ferromagnetic Fe layer, coupled to [Co/Pt]ML multilayer [ML] with perpendicular magnetic anisotropy (PMA), has been studied in-situ with an aim to understand the origin of exchange bias (EB) in orthogonal magnetic anisotropic systems. The interface remanant state of the ML is modified by magnetic field annealing, and the effect of the same on the soft Fe layer is monitored using the in-situ magneto-optical Kerr effect (MOKE). A considerable shift in the Fe layer hysteresis loop from the centre and an unusual increase in the coercivity, similar to exchange bias phenomena, is attributed to the exchange coupling at the [Co/Pt]ML and Fe interface. The effect of the coupling on spin orientation at the interface is further explored precisely by performing an isotope selective grazing incident nuclear resonance scattering (GINRS) technique. Here, the interface selectivity is achieved by introducing a 2 nm thick Fe57 marker between [Co/Pt]ML and Fe layers. Interface sensitivity is further enhanced by performing measurements under the x-ray standing wave conditions. The combined MOKE and GINRS analysis revealed the unidirectional pinning of the Fe layer due to the net in-plane magnetic spin at the interface caused by magnetic field annealing. Unidirectional exchange coupling or pinning at the interface, which may be due to the formation of asymmetrical closure domains, is found responsible for the origin of EB with an unusual increase in coercivity.Comment: 9 figures, 1 tabl

Detection of Ammonia Gas Molecules in Aqueous Medium by Using Nanostructured Ag-Doped ZnO Thin Layer Deposited on Modified Clad Optical Fiber

The synthesis of Ag-doped ZnO nanorod employing hydrothermal process over modified cladd optical fiber is reported. The developed material is characterized using X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), and Brunauer-Emmett-Teller (BET)analysis to evaluate the morphology and the nature of nanorod formed. The initial performance of the coated modified clad optical fiber toward detection of ammonia gas in aqueous solution is also presented. The sensing performance revealed that the developed material possess improved sensitivity toward ammonia gas at room temperature compared to Ag doped nanowires containing optical fiber sensor