Excellence in Research and Innovation for Humanity

International Science Index

Commenced in January 1999 Frequency: Monthly Edition: International Abstract Count: 40418

Physical and Mathematical Sciences

Measurement of Temperature, Humidity and Strain Variation Using Bragg Sensor
Measurement and monitoring of temperature, humidity and strain variation are very requested in great fields and area such as structural health monitoring (SHM) systems. Currently, the use of fiber Bragg grating sensors (FBGS) based on wireless sensor network (WSN) has been recommended in SHM due to the specifications of these sensors. In this paper, we proposed an architecture of wireless SHM system based on FBGS and wireless sensor network. Therefore we try to measure the efficient variation of strain, temperature, and humidity (SV, ST, SH) by modeling the spectrum of FBGS. Thus, we deduce the fundamental relation between these parameters and the wavelength of Bragg grating.
Barium-Ferrite Based Nanocomposite Transparent Radar Absorption Coating for Canopies
It is a big demand to have a wide band, easy to synthesize microwave absorption materials with a high absorption ratio according to their weight for aircraft parts. For the aircraft body lots of proven materials are commercially available. But for the optically transparent parts like canopies, the general approach is using a thin metal coating as a scattering surface. This is an efficient but restrictive method for the aircraft design because a wide angle scatting need to be done geometrically. As a solution in this project we offer a nanostructured barium-ferrite based coating which is more than %80 percent transparent at the visible spectrum. For the coating BaFe12O19, BaGd2Fe10O19 and BaGd2Fe10O19 nanoparticles with different particles size are synthesized by the wet milling process. Their crystal structure analyzed by XRD, mean particle sizes were calculated from XRD patterns using Rietveld analysis and from TEM images which are changing from 21 nm to 10 nm. Magnetic properties are analyzed by using Quantum design VSM. Decrease of particle size gives rise to a decrease at coercivity and saturation magnetization of the samples. Change at the hysteresis loops gives a clue to the change of the microwave absorption frequency which is directly observed from the microwave measurements. Microwave absorption properties are measured by using coaxial transmission method with an Agilent E5071 VNA. BaGd2Fe10O19 and BaGd2Fe10O19 structures show -20 dB background absorption between 8 and 14 GHz. They also show -40 dB resonance absorption peaks that are changing their positions 11 GHz to 13 GHz by the decrease at the particle size. Barium-ferrite nanoparticles coated on to borosilicate glasses to determine their effect on to the optical properties of the glass. UV-VIS measurements showed that coatings with a 300 nm thickness decrease the transparency of the glass with a percentage of %19.
Magnetogenesis in Bouncing Scenarios and Duality Invariance
Magnetic fields have been observed in our universe over a wide variety of scales, ranging from stars and galaxies to the large scale structures and the intergalactic medium. A seed field of primordial origin seems to be essential to explain the prevalence of the magnetic fields on the largest scales. Although inflation is currently considered to be the most favorable scenario to describe the origin of perturbations in the early universe, it seems worthwhile to examine the origin of magnetic fields in alternative scenarios such as the bouncing models. In this work, we discuss the generation of scale invariant magnetic fields in a certain class of bouncing models via breaking the conformal invariance of the electromagnetic action. We show that, for scales of cosmological interest, the shapes of the spectra of the electric and magnetic fields are preserved across the bounce. We also illustrate the `duality' invariance of the power spectrum of the magnetic fields under a two-parameter family of transformations of the non-minimal coupling function.
Heteromolecular Structure Formation in Aqueous Solutions of Ethanol, Tetrahydrofuran and Dimethylformamide
The refractometric method was used to determine optical characteristics of concentration features of aqueous solutions of ethanol, tetrahydrofuran, and dimethylformamide at the room temperature. Changes in dielectric permittivity of aqueous solutions of ethanol, tetrahydrofuran, and dimethylformamide in a wide range of concentrations (~0÷1.0 molar fraction) have been studied using molecular dynamics method. The comparison of curves of the concentration dependence of excessive dielectric permittivity of solutions with experimental data on excess refractive indexes has been carried out. It has been showed that stable heteromolecular complexes in binary solutions are formed in the concentration range of 0.3÷0.4 molar fractions. To plot calculated dielectric spectra, the dipole-dipole autocorrelation functions of systems were obtained. The imaginary part of static dielectric constant shifts toward low frequencies in the range of ethanol, tetrahydrofuran and dimethylformamide concentrations x ≤ 0.5 molar fraction, due to the formation of heteromolecular structures with hydrogen bonds. This is confirmed by the extremum values of excessive dielectric permittivity and excessive refractive index of aqueous solutions.
Magneto-Optical Properties in Transparent Region of Implanted Garnet Films
In devices based on magneto-optical materials are used Faraday and Kerr magneto-optical effects. In this perspective, practical importance is given to ion implanted ferrite-garnet films as ion implantation weakens cylindrical magnetic domains, and it subsequently contributes to better use of their parameters. We investigated magneto-optical Kerr effect in transparent region of implanted ferrite-garnet films for the (YBiCa)3(FeGe)5O12. We discovered that slight deviation plane of external alternating magnetic field from plane of sample leads to appearance intensive magneto-optical maximum in transparent region of garnet films ħω=0.5-2.3 eV. In the proceeding, we have also found that the deviation polarization plane from P- component of incident light leads to the appearance of the similar magneto-optical effects in this region. The research of magnetization processes in transparent region of garnet films showed that the formation of magneto-optical effects in region ħω =0.5-2.3 eV has a rather complex character.
Combining Raman and Laser Induced Breakdown Spectroscopy by Double Pulse Technique
A new approach combining Raman spectrometry and Laser induced breakdown spectrometry (LIBS) was suggested. Nearly the same laser systems and detectors are used for both techniques (Raman and LIBS) but two measurements need different levels of laser power density. The conventional way to combine two methods is to separately measure Raman and LIBS spectra by adjusting laser pulse energy for every measurement or to use two different experiment setup (two different lasers or/and two spectrometers). Consequently, the same location at sample surface cannot be measured with LIBS and Raman methods in case of moving objects analysis or in laser remote sensing applications. A double pulse mode lasing (two laser pulses with microsecond delay) was used to combine two spectrometry methods within a single laser event. First low-energy laser pulse (power density far below ablation threshold) was used for Raman measurements while second powerful laser pulse creates the plasma suitable for LIBS analysis. The time delay between two pulses was adjusted in 30-60 µs range that allows measuring LIBS and Raman spectra in different moments but within a single laser event. The feasibility of combined Raman and LIBS spectrometry measurements was demonstrated for solid and liquid samples. A mixture of calcite and aragonite crystals with different additives was used as a test sample for Raman and LIBS measurements by the technique suggested. Carbonates, sulfates and single wall carbon nanotubes samples were quantitatively analysed (molecular and elemental) by combined Raman and LIBS method. The perspectives of combined Raman and LIBS analysis for laser remote sensing applications are discussed. Raman signal enhancement by multiple scattering inside laser crater cones was observed for the first time. Laser crater enhanced Raman spectroscopy yielded a 14-fold increase in the Raman spectra bands due to efficient multiple scattering of laser irradiation within the laser crater walls. The same pulsed Nd:YAG laser (532 nm, 10 ns) was used for both laser crater formation and Raman scattering experiments by varying the output pulse energy. First, powerful pulses are used to produce the laser crater and then low energy pulses are used to perform Raman scattering measurements. The laser crater profile and its alignment with the laser beam waist were found to be the key parameters for the optimization of the Raman bands intensity enhancement. Raman intensity enhancement resulted from increased surface scattering area at the crater walls rather than spatially offset Raman scattering. The increased signal-to-noise ratio resulted in limits of detection improvement for quantitative analysis.
A Comparative Study of a Defective Superconductor/Semiconductor-Dielectric Photonic Crystal
Temperature-dependent tunable photonic crystals have attracted widespread interest in recent years. In this research, transmission characteristics of a one-dimensional photonic crystal structure with a single defect have been studied. Here, we assume two different defect layers: InSb as a semiconducting layer and HgBa2Ca2Cu3O10 as a high-temperature superconducting layer. Both the defect layers have temperature-dependent refractive indexes. Two different types of dielectric materials (Si as a high-refractive index dielectric and MgF2 as a low-refractive index dielectric) are used to construct the asymmetric structures (Si/MgF2)NInSb(Si/MgF2)N named S.I, and (Si/MgF2) NHgBa2Ca2Cu3O10 (Si/MgF2)N named S.II. It is found that in response to the temperature changes, transmission peaks within the photonic band gap of the S.II structure, in contrast to S.I, show a small wavelength shift. Furthermore, the results show that under the same conditions, S.I structure generates an extra defect mode in the transmission spectra. Besides high-efficiency transmission property of S.II structure, it can be concluded that the semiconductor-dielectric photonic crystals are more sensitive to temperature variation than superconductor types.
Low Cost Hybrid Two Dimensional Optical Microscanner for Endoscopic Imaging
Optical scanning endoscopic imaging techniques require a miniaturized microscanner locating at the distal end of the imaging probe for beam steering. Microelectromechanical systems (MEMS) based microscanners were firstly introduced for side-view imaging. Piezo microactuators vibrating optical fibers to project patterns is the dominating method for forward imaging. However, most of endoscopic optical probes aforementioned have a needle shape with rigid parts as long as 40 mm. It is difficult for them to work within the instrument channel of commercial medical endoscopes for clinical imaging. The low-cost hybrid two-dimensional optical microscanner presented in this article is mainly composed of a planar lightwave circuit (PLC) beam deflector for the fast-axis and a flexible printed circuit (FPC) beam deflector for the slow-axis. The PLC beam deflector uses a microheater prism array (MPA) to rapidly modulate the temperature of polymer layer beneath the MPA. Based on the thermo-optic (TO) effect, the refractive index of polymer layers decreases as the temperature increases. The PLC beam deflector provides 512 resolvable spots in a scan line, and its outline dimension is 6.14 mm by 2.31 mm by 0.45 mm. 2 um LOR_A, 3.6 um Durimide 112A and 2 um LOR_A are spin-coated and cured to form the top cladding layer, the core layer and the bottom cladding layer of the PLC. The refractive indices of the LOR_A are 1.61@405nm and 1.55@780nm while that of the Durimide 112A is 1.81. Aromatic PI and PMGI exhibit large to coefficients as about -4x10-4/K. 200 nm thickness aluminum is patterned as MPA on the top surface of the PLC by lift-off. A FPC beam deflector includes a pair of four-layer cantilevers composed of 0.1 um gold, 3 um nickel, 18 um copper and 50 um PI substrate. Due to the bi-metallic effect, when heated, they perform a curved shape to tip a reflective mirror plate for beam steering in the other direction. The PLC is attached on the folded FPC by 45°. A thin silicon board is attached under the FPC to support the wire bonding process and align two rod lenses which have the diameter of 1 mm and the length of 2 mm. Both a 405 nm laser diode and a 780 nm femtosecond fiber laser are used for devices characterization. About 8.6°@6.9 W for the PLC and 12.4°@1.1 W for the FPC are experimentally achieved. The response time to the step input of the PLC is measured about 1.3 ms. The frequency response of FPC cantilevers is found to be 1.2 Hz for -3dB bandwidth. For nonlinear optics applications, the laser pulse broadening caused by the group velocity delay (GVD) or the self-phase modulation (SPM) in the PLC is also measured by an autocorrelator. The result indicates that there is no significant incompensatable SPM effect observed. By assembling two beam deflectors together as well as two rod lens for focusing and collimation, a hybrid two dimensional optical microscanner highlights small outline dimension, low drive voltage and low fabrication cost.
Mechanical Study Printed Circuit Boards Bonding for Jefferson Laboratory Detector
One plane X and one plane Y of silicon microstrip detectors will constitute the front part of the Super Bigbite Spectrometer that is under construction and that will be installed in the experimental Hall A of the Thomas Jefferson National Accelerator Facility (Jefferson Laboratory), located in Newport News, Virgina, USA. Each plane will be made up by two nearly identical, 300 μm thick, 10 cm x 10.3 cm wide silicon microstrip detectors with 50 um pitch, whose electronic signals will be transferred to the front-end electronic based on APV25 chips through C-shaped FR4 Printed Circuit Boards (PCB). A total of about 10000 strips are read-out. This paper treats the optimization of the detector support structure, the materials used through a finite element simulation. A very important aspect of the study will also cover the optimization of the bonding parameters between detector and electronics.
Numerical Prediction of Wall Eroded Area by Cavitation
This study presents a new method to predict cavitation area that may be eroded. It is based on the post-treatment of URANS simulations in cavitant flows. The most RANS calculations with incompressible consideration are based on cavitation model using mixture fluid with density (ρm) calculated as a function of liquid density (ρliq), vapour or gas density (ρvap) and vapour or gas volume fraction α (ρm = αρvap + (1-α) ρliq). The calculations are performed on hydrofoil geometries and compared with experimental works concerning flows characteristics (size of pocket, pressure, velocity). We present here the used cavitation model and the approach followed to evaluate the value of α fixing the shape of pocket around wall before collapsing.
Exchange-Coupled MnBi/MnB Nanocomposite Magnets
Exchange-coupled nanocomposite magnets are composed of magnetically hard and soft phases, which interact by magnetic exchange coupling. These magnets have a large potential for advanced permanent magnetic applications, as they have a large energy product (BH)max when compared to single-phase magnetic materials. The large (BH)max of the exchange-coupled nanocomposite magnets originates from the combination of permanent magnet field and magnetization. In this work, high-performance exchange-coupled MnBi/MnB nanocomposite magnet was produced. Firstly, the functionality of the magnetically soft MnB phase was proved by density functional theory (DFT) calculations showing 1.915 μB magnetic property per MnB unit that corresponds to 158 emu/g at 0 K. MnxB100-x alloys were produced experimentally by arc melting technique. Structural analysis showed that starting melting from Mn55B45 composition results in single phase orthorhombic MnB structure. The chemical composition of the as-made sample was also confirmed by XPS analysis as Mn48.2B51.8. In addition, homogeneity and single phase properties of the as-made sample were also proved by BSE and EDS analysis. Magnetic characterizations showed that MnB alloy has a saturation magnetization of 130 emu/g, anisotropy constant of 517x103 erg/g and Curie temperature of 566 K. For exchange-coupling with a hard phase, bulk MnB alloy was milled for controlled durations. Results showed that 7 h of milling reduced the crystallite size to 11.6 nm and saturation magnetization to 85 emu/g. Secondly, the promising hard MnBi alloys were produced by arc melting. For transformation into low temperature phase, samples were annealed for controlled durations at 575 K in a vacuum furnace. Then samples were milled for 10 h. As produced MnBi nanoparticles were found to have 51.7 emu/g saturation magnetization and 12.2 kOe coercivity. This sample was chosen to be the hard phase in MnBi/MnB nanocomposite magnets. In the last part of the study, MnBi/MnB nanocomposite magnet was produced. When MnBi/MnB composite contains 10% MnB in weight, (BH)max product was increased to 5.74 MGOe value. This result shows that addition of 10% soft phase to the MnBi, leads 12% increase in the maximum energy product of the magnet. To sum up, the exchange-coupling of the soft MnB and hard MnBi magnetic phases significantly increases the magnets' performance.
Analysis of Secondary Peak in Hα Emission Profile during Gas Puffing in Aditya Tokamak
Efficient gas fueling is a critical aspect that needs to be mastered in order to maintain plasma density, to carry out fusion. This requires a fair understanding of fuel recycling in order to optimize the gas fueling. In Aditya tokamak, multiple gas puffs are used in a precise and controlled manner, for hydrogen fueling during the flat top of plasma discharge which has been instrumental in achieving discharges with enhanced density as well as energy confinement time. Following each gas puff, we observe peaks in temporal profile of Hα emission, Soft X-ray (SXR) and chord averaged electron density in a number of discharges, indicating efficient gas fueling. Interestingly, Hα temporal profile exhibited an additional peak following the peak corresponding to each gas puff. These additional peak Hα appeared in between the two gas puffs, indicating the presence of a secondary hydrogen source apart from the gas puffs. A thorough investigation revealed that these secondary Hα peaks coincide with Hard X- ray bursts which come from the interaction of runaway electrons with vessel limiters. This leads to consider that the runaway electrons (REs), which hit the wall, in turn, bring out the absorbed hydrogen and oxygen from the wall and makes the interaction of REs with limiter a secondary hydrogen source. These observations suggest that runaway electron induced recycling should also be included in recycling particle source in the particle balance calculations in tokamaks. Observation of two Hα peaks associated with one gas puff and their roles in enhancing and maintaining plasma density in Aditya tokamak will be discussed in this paper.
Investigation of Nd-Al-Fe Added Nd-Fe-B Alloy Produced by Arc Melting
The scope of this study, to investigate the magnetic properties and microstructure of Nd₂Fe₁₄B₁ by alloying with Nd₃₃.₄Fe₆₂.₆Al₄, and heat treating it at different temperatures. The stoichiometric Nd₂Fe₁₄B hard magnetic alloy and Nd₃₃.₄Fe₆₂.₆Al₄ composition was produced by arc melting under argon atmosphere. The Nd₃₃.₄Fe₆₂.₆Al₄ alloy has added to the 2:14:1 hard magnetic alloy with 48% by weight, and melted again by arc melting. Then, it was heat treated at 600, 700 and 800˚C for 3h under vacuum. In AC magnetic susceptibility measurements, for the as-cast sample, the signals decreased sharply at 101 ˚C and 313 ˚C corresponding to the Curie temperatures of the two ferromagnetic phases in addition to Fe phase. For the sample annealed at 600 ˚C, two Curie points were observed at about 257˚C and at 313˚C. However, the phase corresponding to the Curie temperature of 101 ˚C was disappeared. According to the magnetization measurements, the saturation magnetization has the highest value of 99.8 emu/g for the sample annealed at 600 ˚C, and decreased to 57.66 and 28.6 emu/g for the samples annealed at 700˚ and 800 ˚C respectively. Heat treatment resulted in an evolution of the new phase that caused changes in magnetic properties of the alloys. In order to have a clear picture, the identification of these phases are being under the investigation by XRD and SEM–EDX analysis.
Secure E-Pay System Using Steganography and Visual Cryptography
Today’s internet world is highly prone to various online attacks, of which the most harmful attack is Phishing. The attackers host the fake websites which are very similar and look alike. We propose an image-based authentication using Steganography and Visual Cryptography to prevent phishing. This paper presents a secure Steganographic technique for true color (RGB) images and uses Discrete Cosine Transform to compress the images. The proposed method hides the secret data inside the cover image. The use of visual cryptography is to preserve the privacy of an image by decomposing the original image into two shares. Original image can be identified only when both qualified shares are simultaneously available. Individual share does not reveal the identity of the original image. Thus, the existence of the secret message is hard to be detected by the RS steganalysis.
Synthesis, Spectral, Thermal, Optical and Dielectric Studies of Some Organic Arylidene Derivatives
Arylidene derivatives are the subclass of chalcone derivatives. Chalcone derivatives are studied widely for the past decade because of its nonlinearity. To seek new organic group of crystals which suit for fabrication of optical devices, three-member organic arylidene crystals were synthesized by using Claisen–Schmidt condensation reaction. Good quality crystals were grown by slow evaporation method. Functional groups were identified by FT-IR and FT-Raman spectrum. Optical transparency and optical band gap were determined by UV-Vis-IR studies. Thermal stability and melting point were calculated using TGA and DSC. Variation of dielectric loss and dielectric constant with frequency were calculated by dielectric measurement.
The Data Acquisition Systems Debugger for Field-Programmable Gate Array-Based Data Acquisition System of the COMPASS Experiment
In general, state-of-the-art Data Acquisition Systems (DAQ) must satisfy the requirements of the reliability, the efficiency, and the data rate capability in high energy physics experiments. This paper presents the development and deployment of the DAQ Debugger for the intelligent, FPGA-based Data Acquisition System (iFDAQ) of the COMPASS experiment at CERN. Utilizing a hardware event builder, the iFDAQ is designed to be able to readout data at the average maximum rate of 1.5 GB/s of the experiment. In complex softwares, such as the iFDAQ, having thousands of lines of code, the debugging process is absolutely essential to reveal all software issues. Unfortunately, the conventional debugging of the iFDAQ is not possible during the real data taking. The DAQ Debugger is a tool for identifying a problem, isolating the source of the problem, and then either correcting the problem or determining a way to work around it. It provides the layer for an easy integration to any process and has no impact on the readout performance. Based on the handling of system signals, the DAQ Debugger represents an alternative to the conventional debuggers provided by most integrated development environments. Whenever any problem occurs, it generates reports containing all necessary information important for a deeper investigation and analysis. The DAQ Debugger was fully incorporated to all processes in the iFDAQ during the run 2016. It helped to reveal remaining software issues and improved significantly the stability of the system in comparison with the previous run. In the paper, we present the DAQ Debugger from several insights and discuss it in a detailed way.
Effectiveness of Radon Remedial Action Implemented in a School on the Island of Ischia
The aim of this study is to evaluate the efficacy of radon remedial action in a school on the Ischia island, South Italy, affected by indoor radon concentration higher than the value of 500 Bq/m3 which is the limit imposed by the Italian legislation, above which is necessary to put in place remedial actions in schools. Before the application of remedial action, indoor radon concentrations were measured in 9 rooms of the school selected among offices, classrooms and laboratories. The measurements were performed with LR-115 passive alpha detectors (SSNTDs) and E-Perm. The remedial action was conducted in one of the office affected by high radon concentration using a Radonstop paint applied after the construction of a concrete slab under the floor. The effect of remedial action was the reduction of the concentration of radon of 41% and moreover it has demonstrated to be durable over time. The chosen method is cheap and easy to apply and it could be designed for various type of building. In this way it could be provided radon protection in both new and existing building.
Gravitationally Confined Relativistic Neutrinos and Mathematical Modeling of the Structure of Pions
We use special relativity to compute the inertial and thus gravitational mass of relativistic electron and muon neutrinos, and we find that, for neutrino kinetic energies above 150 MeV/c2, these masses are in the Planck mass range. Consequently, we develop a simple Bohr-type model using gravitational rather than electrostatic forces between the rotating neutrinos as the centripetal force in order to examine the bound rotational states formed by two or three such relativistic neutrinos. We find that the masses of the composite rotational structures formed, are in the meson and baryon mass ranges, respectively. These models contain no adjustable parameters and by comparing their predictions with the experimental values of the masses of protons and pions, we compute a mass of 0.0437 eV/c2 for the heaviest electron neutrino mass and of 1.1 x10-3 eV/c2 for the heaviest muon neutrino mass.
Hydrogen Peroxide: A Future for Well Stimulation and Heavy Oil Recovery
Well stimulation and heavy oil recovery continue to be a hot topic in our industry, particularly with formation damage and viscous oil respectively. Cyclic steam injection has been recognised for most of the operations related to heavy oil recovery. However, the cost of implementation is high and operation is time-consuming, moreover most of the viscous oil reservoirs such as oil sands, Bitumen deposits and oil shales require additional treatment of well stimulation. The use of hydrogen peroxide can efficiently replace the cyclic steam injection process as it can be used for both well stimulation and heavy oil recovery simultaneously. The decomposition of Hydrogen peroxide produces oxygen, superheated steam and heat. The increase in temperature causes clays to shrink, destroy carbonates and remove emulsion thus it can efficiently remove the near wellbore damage. The paper includes mechanisms, parameters to be considered and the challenges during the treatment for the effective hydrogen peroxide injection for both conventional and heavy oil reservoirs.
Character Bioacoustics White-Rumped Shama Copsychus Malabaricus as a Cage-Bird
Indonesian people love to keep songbird in cage to be competed, such as White-rumped Shama (Copsychus malabaricus). Each individual White-rumped Shama will be pitted their song and try to imitate the rhythm of the enemy with its songs. This study was conducted to see the natural song characters of White-rumped Shama and song character from birds that had been trained and comparison in three different places in West Sumatra. Individuals were recorded totaling 30 individuals in three areas in West Sumatra namely Padang, Solok and Pariaman and sound recordings of White-rumped Shama in nature were taken in HBW and Xenocanto website. Research has done conducted from June to October 2016 at place group practice of birdsongs and recorded at 16:00 to 18:00 pm. These voices were analyzed by Avisoft SAS-Lab Lite inform of oscillogram and sonogram. Measured parameters included: the length of voice, repertoire size, number of syllable type, syllable repertoire, and song repertoire. The results showed that repertoire composition of White-rumped Shama in nature less than the sound which was trained and has repeat songs composed by the same type of repertoire composition. Comparison of song character White-rumped Shama in three different places in West Sumatra, those birds in Solok had the best quality of voice or song than Padang and Pariaman. It showed by higher repertoire composition in Solok.
Developing Optical Sensor with Laser Pulse Code Detection System Using Pulse Repetition Frequency Based on Microcontroller
In this paper, we describe and enhance detection and tracking of laser guided weapon decoding system based on microcontroller. The system is designed to receive the reflected pulse through a four quadrant laser detector and process the received laser pulses through an electronic circuit, which send data to the microcontroller for decoding laser signal reflected by the target. The laser seeker accuracy will be improved by the decoding system, which reduced the time of laser detection by reducing the number of received pulse to detect the code and generating a narrow gate signal to improve the anti-jamming ability. We implement a model of the laser pulse code detection system based on Pulse Repetition Frequency technique with two microcontroller units (MCU). MCU1 generates laser pulses with different codes and also communicate with switches to control which code is selected. MCU2 recognizes the laser code and locks the system at the specific code. The locked frequency can be changed in both MCUs by switches selection. The system is implemented and tested in Proteus Software for laser code compatibility, laser code rejection. The concept is hardware implemented and used to evaluate the performance of 4-quadrant detector with laser pulse code detection. The hardware system is tested for laser code compatibility, immunity to false laser codes and laser code resolution. The system test results show that the system can detect the laser code with only 3 received pulses based on the narrow gate signal and good agreement between simulation and measured system performance as presented.
Study of Magnetic Nanoparticles’ Endocytosis in a Single Cell Level
Magnetic cell labeling is of great importance in various applications in biomedical fields such as cell separation and cell sorting. Since analytical methods for quantification of cell uptake of magnetic nanoparticles (MNPs) are already well established, image analysis on single cell level still needs more characterization. This study reports an alternative non-destructive quantification methods of single-cell uptake of positively charged MNPs. Magnetophoresis experiments were performed to calculate the number of MNPs in a single cell. Mobility of magnetic cells and the area of intracellular MNP stained by Prussian blue were quantified by image processing software. ICP-MS experiments were also performed to confirm the internalization of MNPs to cells. Initial results showed that the magnetic cells incubated at 100 µg and 50 µg MNPs/mL concentration move at 18.3 and 16.7 µm/sec, respectively. There is also an increasing trend in the number and area of intracellular MNP with increasing concentration. These results could be useful in assessing the nanoparticle uptake in a single cell level.
Detection and Identification of Antibiotic Resistant Bacteria Using Infra-Red-Microscopy and Advanced Multivariate Analysis
Antimicrobial drugs have an important role in controlling illness associated with infectious diseases in animals and humans. However, the increasing resistance of bacteria to a broad spectrum of commonly used antibiotics has become a global health-care problem. Rapid determination of antimicrobial susceptibility of a clinical isolate is often crucial for the optimal antimicrobial therapy of infected patients and in many cases can save lives. The conventional methods for susceptibility testing like disk diffusion are time-consuming and other method including E-test, genotyping are relatively expensive. Fourier transform infrared (FTIR) microscopy is rapid, safe, and low cost method that was widely and successfully used in different studies for the identification of various biological samples including bacteria. The new modern infrared (IR) spectrometers with high spectral resolution enable measuring unprecedented biochemical information from cells at the molecular level. Moreover, the development of new bioinformatics analyses combined with IR spectroscopy becomes a powerful technique, which enables the detection of structural changes associated with resistivity. The main goal of this study is to evaluate the potential of the FTIR microscopy in tandem with machine learning algorithms for rapid and reliable identification of bacterial susceptibility to antibiotics in time span of few minutes. The bacterial samples, which were identified at the species level by MALDI-TOF and examined for their susceptibility by the routine assay (micro-diffusion discs), are obtained from the bacteriology laboratories in Soroka University Medical Center (SUMC). These samples were examined by FTIR microscopy and analyzed by advanced statistical methods. Our results, based on 550 E.coli samples, were promising and showed that by using infrared spectroscopic technique together with multivariate analysis, it is possible to classify the tested bacteria into sensitive and resistant with success rate higher than 85% for eight different antibiotics. Based on these preliminary results, it is worthwhile to continue developing the FTIR microscopy technique as a rapid and reliable method for identification antibiotic susceptibility.
Computational Fluid Dynamics Analysis for Radon Dispersion Study and Mitigation
Computational fluid dynamics (CFD) is used to simulate the distribution of indoor radon concentration in a living room with elevated levels of radon concentration which varies from 22 Bqm-3 to 1533 Bqm-3 in 24 hours. Finite volume method (FVM) was used for the simulation. The simulation results were experimentally validated at 16 points in two horizontal planes (y=1.4m & y=2.0m) using pin-hole dosimeters and at 3 points using scintillation radon monitor (SRM). Passive measurement using pin-hole dosimeters were performed in all seasons. Another simulation was done to find a suitable position for a passive ventilation system for the effective mitigation of radon.
Constructing the Density of States from the Parallel Wang Landau Algorithm Overlapping Data
This work focuses on building an efficient universal procedure to construct a single density of states from the multiple pieces of data provided by the parallel implementation of the Wang Landau Monte Carlo based algorithm. The Ising and Pott models were used as the examples of the two-dimensional spin lattices to construct their densities of states. Sampled energy space was distributed between the individual walkers with certain overlaps. This was made to include the latest development of the algorithm as the density of states replica exchange technique. Several factors of immediate importance for the seamless stitching process have being considered. These include but not limited to the speed and universality of the initial parallel algorithm implementation as well as the data post-processing to produce the expected smooth density of states.
Study on Intensity Modulated Non-Contact Optical Fiber Vibration Sensors of Different Configurations
Optical fibers are widely used in the measurement of several physical parameters like temperature, pressure, vibrations etc. Measurement of vibrations plays a vital role in machines. In this paper, three fiber optic non-contact vibration sensors were discussed, which are designed based on the principle of light intensity modulation. The Dual plastic optical fiber, Fiber optic fused 1x2 coupler and Fiber optic fused 2x2 coupler vibration sensors are compared based on range of frequency, resolution and sensitivity. It is to conclude that 2x2 coupler configuration shows better response than other two sensors.
Design of a Remote Radiation Sensing Module Based on Portable Gamma Spectrometer
A personal gamma spectrometer has to be sensitive, pocket-sized, and carriable on the users. To serve these requirements, we developed the SiPM-based portable radiation detectors. The prototype uses a Ce:GAGG scintillator coupled to a silicon photomultiplier and a radio frequency(RF) module to measure gamma-ray, and can be accessed wirelessly or remotely by mobile equipment. The prototype device consumes roughly 4.4W, weighs about 180g (including battery), and measures 5.0 7.0. It is able to achieve 5.8% FWHM energy resolution at 662keV.
Simulation for the Magnetized Plasma Compression Study
Ongoing experimental and theoretical studies on magneto-inertial confinement fusion (Angara, C-2, CJS-100, General Fusion, MagLIF, MAGPIE, MC-1, YG-1, Omega) and new constructing facilities (Baikal, C-2W, Z300 and Z800) require adequate modeling and description of the physical processes occurring in high-temperature dense plasma in a strong magnetic field. This paper presents a mathematical model, numerical method, and results of the computer analysis of the compression process and the energy transfer in the target plasma, used in magneto-inertial fusion (MIF). The computer simulation of the compression process of the magnetized target by the high-power laser pulse and the high-speed plasma jets is presented. The characteristic patterns of the two methods of the target compression are being analysed.
Accuracy of Computed Tomography Dose Monitor Values: A Multicentric Study in India
The quality of Computed Tomography (CT) procedures has improved in recent years due to technological developments and increased diagnostic ability of CT scanners. Due to the fact that CT doses are the peak among diagnostic radiology practices, it is of great significance to be aware of patient’s CT radiation dose whenever a CT examination is preferred. CT radiation dose delivered to patients in the form of volume CT dose index (CTDIvol) values, is displayed on scanner monitors at the end of each examination and it is an important fact to assure that this information is accurate. The objective of this study was to estimate the CTDIvol values for great number of patients during the most frequent CT examinations, to study the comparison between CT dose monitor values and measured ones, as well as to highlight the fluctuation of CTDIvol values for the same CT examination at different centres and scanner models. The output CT dose indices measurements were carried out on single and multislice scanners for available kV, 5 mm slice thickness, 100 mA and FOV combination used. The 100 CT scanners were involved in this study. Data with regard to 15,000 examinations in patients, who underwent routine head, chest and abdomen CT were collected using a questionnaire sent to a large number of hospitals. Out of the 15,000 examinations, 5000 were head CT examinations, 5000 were chest CT examinations and 5000 were abdominal CT examinations. Comprehensive quality assurance (QA) was performed for all the machines involved in this work. Followed by QA, CT phantom dose measurements were carried out in South India using actual scanning parameters used clinically by the hospitals. From this study, we have measured the mean divergence between the measured and displayed CTDIvol values were 5.2, 8.4, and -5.7 for selected head, chest and abdomen procedures for protocols as mentioned above, respectively. Thus, this investigation revealed an observable change in CT practices, with a much wider range of studies being performed currently in South India. This reflects the improved capacity of CT scanners to scan longer scan lengths and at finer resolutions as permitted by helical and multislice technology. Also, some of the CT scanners have used smaller slice thickness for routine CT procedures to achieve better resolution and image quality. It leads to an increase in the patient radiation dose as well as the measured CTDIv, so it is suggested that such CT scanners should select appropriate slice thickness and scanning parameters in order to reduce the patient dose. If these routine scan parameters for head, chest and abdomen procedures are optimized than the dose indices would be optimal and lead to the lowering of the CT doses. In South Indian region all the CT machines were routinely tested for QA once in a year as per AERB requirements.
Quantitative Elemental Analysis of Cyperus rotundus Medicinal Plant by Particle Induced X-Ray Emission and ICP-MS Techniques
Particle Induced X-ray Emission (PIXE) and Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) techniques have been employed in this work to determine the elements present in the root of Cyperus rotundus medicinal plant used in the treatment of rheumatoid arthritis. The elements V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Rb, and Sr were commonly identified and quantified by both PIXE and ICP-MS whereas the elements Li, Be, Al, As, Se, Ag, Cd, Ba, Tl, Pb and U were determined by ICP-MS and Cl, K, Ca, Ti and Br were determined by PIXE. The regional variation of elemental content has also been studied by analyzing the same plant collected from different geographical locations. Information on the elemental content of the medicinal plant would be helpful in correlating its ability in the treatment of rheumatoid arthritis and also in deciding the dosage of this herbal medicine from the metal toxicity point of view. Principal component analysis and cluster analysis were also applied to the data matrix to understand the correlation among the elements.