Design and Development of a Single Channel Analyzer with Microcontroller Based Controlled Output

Single Channel Analyzer (SCA) is a most common device used in today\u27s nuclear world. Therefore, A SCA with microcontroller based controlled output has been proposed in this article. The system comprises of Lower Level Discriminator (LLD), Upper Level Discriminator (ULD), wide dynamic range, Fast Processing and Hysteresis. The Comparator LM339N used as the key component that performs the main function of the proposed nuclear module. The multi-turn potentiometers have been used as LLD and ULD for the incoming linear pulses from shaping amplifier. The system has also employ the Hysteresis facilities so that oscillations due to stray feedback are not possible. A lower pin and less housing PIC microcontroller (P16F676) has been used to control the width and time delay of the output pulses

Elemental Study of Bangladeshi Fish Samples Using PIGE Technique

Proton induced gamma emission (PIGE) method has been developed at the Accelerator Laboratory of Atomic Energy Center, Dhaka (AECD) for the investigation of various human health related specimens. In the present study PIGE analytical technique has been used for the determination of numerous trace elements in some commonly used fish samples which were collected from Islampur area at Savar. During the experimental work the γrays emitted from the prepared fish samples were measured using a Highpurity Germenium (HPGe) detector. The detected 18 elements were Iron, Calcium, Sodium, Magnesium, Aluminum, Potassium, Vanadium, Chromium, Manganese, Copper, Zinc, Selenium, Bromine, Rubidium, Strontium, Cadmium, Iodine, Lead etc. The objective of this study was to measure the concentrations of these trace elements in the collected fish samples and to investigate whether their concentrations are harmful for human health by comparison with limits set by WHO/FAO. The results obtained indicate that Fe, K and Ca concentrations were relatively high in all samples as compared with the other elements. The measured elemental concentration of Fe, Mn, Zn, Cu, Cr and V in all fish samples were found to be above the WHO/FAO recommended limits

Diversity and occurrence of seaweeds from the south-eastern coast of Bangladesh

1379-1388The present investigation was carried out to prepare a checklist of the seaweeds along with the diversity and distribution pattern in the south-eastern Bangladesh coast. The study was performed in the northern Bay of Bengal during October 2015 to April 2018. From the findings of the present study, it was observed that seaweeds did not occur permanently. Some species were observed only for short periods while other species were recorded for 5-7 months. A total of 117 species were recorded, amongst these 62 species belong to the Rhodophyta group, 31 species belong to the Phaeophyta and 24 species belong to the Chlorophyta group. The species occurrence varied both spatially and temporally. Highest diversity (102 species) of species recorded in Saint Martin Island while the lowest diversity (09 species) was found in Bakkhali, Cox's Bazar coast. This study provides a complete species list to fill up information lacking regarding the ecology of seaweeds in the northern Bay of Bengal coast

Bose-Hubbard model with occupation dependent parameters

We study the ground-state properties of ultracold bosons in an optical lattice in the regime of strong interactions. The system is described by a non-standard Bose-Hubbard model with both occupation-dependent tunneling and on-site interaction. We find that for sufficiently strong coupling the system features a phase-transition from a Mott insulator with one particle per site to a superfluid of spatially extended particle pairs living on top of the Mott background -- instead of the usual transition to a superfluid of single particles/holes. Increasing the interaction further, a superfluid of particle pairs localized on a single site (rather than being extended) on top of the Mott background appears. This happens at the same interaction strength where the Mott-insulator phase with 2 particles per site is destroyed completely by particle-hole fluctuations for arbitrarily small tunneling. In another regime, characterized by weak interaction, but high occupation numbers, we observe a dynamical instability in the superfluid excitation spectrum. The new ground state is a superfluid, forming a 2D slab, localized along one spatial direction that is spontaneously chosen.Comment: 16 pages, 4 figure

Characterisation of the MALT90 Survey and the Mopra Telescope at 90 GHz

We characterise the Millimetre Astronomy Legacy Team 90 GHz Survey (MALT90) and the Mopra telescope at 90 GHz. We combine repeated position-switched observations of the source G300.968+01.145 with a map of the same source in order to estimate the pointing reliability of the position-switched observations and, by extension, the MALT90 survey; we estimate our pointing uncertainty to be 8 arcsec. We model the two strongest sources of systematic gain variability as functions of elevation and time-of-day and quantify the remaining absolute flux uncertainty. Corrections based on these two variables reduce the scatter in repeated observations from 12%–25% down to 10%–17%. We find no evidence for intrinsic source variability in G300.968+01.145. For certain applications, the corrections described herein will be integral for improving the absolute flux calibration of MALT90 maps and other observations using the Mopra telescope at 90 GHz

MALT90 Kinematic Distances to Dense Molecular Clumps

Using molecular-line data from the Millimetre Astronomy Legacy Team 90 GHz Survey (MALT90), we have estimated kinematic distances to 1905 molecular clumps identified in the ATLASGAL 870 μm continuum survey over the longitude range 295° < l < 350°. The clump velocities were determined using a flux-weighted average of the velocities obtained from Gaussian fits to the HCO+, HNC, and N2H+ (1–0) transitions. The near/far kinematic distance ambiguity was addressed by searching for the presence or absence of absorption or self-absorption features in 21 cm atomic hydrogen spectra from the Southern Galactic Plane Survey. Our algorithm provides an estimation of the reliability of the ambiguity resolution. The Galactic distribution of the clumps indicates positions where the clumps are bunched together, and these locations probably trace the locations of spiral arms. Several clumps fall at the predicted location of the far side of the Scutum–Centaurus arm. Moreover, a number of clumps with positive radial velocities are unambiguously located on the far side of the Milky Way at galactocentric radii beyond the solar circle. The measurement of these kinematic distances, in combination with continuum or molecular-line data, now enables the determination of fundamental parameters such as mass, size, and luminosity for each clump

Enzymatic glyceride synthesis in a foam reactor

We report the results of our study on Rhizomucor miehei lipaseâ catalyzed lauric acidâ glycerol esterification in a foam reactor. A satisfactory yield of glyceride synthesis can be achieved with an unusually high initial water content (50% w/w). We found that product formation could be regulated by controlling foaming. Foaming was a function of the air flow rate, reaction temperature, pH value, ionic strength, and substrate molar ratio. Monolaurin and dilaurin, which constituted nearly 80% of the total yield, were the two dominant products in this reaction; trilaurin was also formed at the initial stages of the reaction. A study of pH and ionic strength effects on an independent basis revealed that they affect the interfacial mechanism in different manners. On varying the ratio of lauric acid and glycerol, only a slight change in the degree of conversion was detected and the consumption rate of fatty acid was approximately the same.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141443/1/aocs0643.pd

MALT90: The Millimetre Astronomy Legacy Team 90 GHz Survey

The Millimetre Astronomy Legacy Team 90 GHz (MALT90) survey aims to characterise the physical and chemical evolution of high-mass star-forming clumps. Exploiting the unique broad frequency range and on- the-fly mapping capabilities of the Australia Telescope National Facility Mopra 22 m single-dish telescope∗ , MALT90 has obtained 3′ × 3′ maps toward _2000 dense molecular clumps identified in the ATLASGAL 870 μm Galactic plane survey. The clumps were selected to host the early stages of high-mass star formation and to span the complete range in their evolutionary states (from prestellar, to protostellar, and on to HII regions and photodissociation regions). Because MALT90 mapped 16 lines simultaneously with excellent spatial (38) and spectral (0.11 km s−1) resolution, the data reveal a wealth of information about the clump’s morphologies, chemistry, and kinematics. In this paper we outline the survey strategy, observing mode, data reduction procedure, and highlight some early science results. All MALT90 raw and processed data products are available to the community. With its unprecedented large sample of clumps, MALT90 is the largest survey of its type ever conducted and an excellent resource for identifying interesting candidates for high resolution studies with ALMA

Xylanase and β-xylosidase production by Aspergillus ochraceus: new perspectives for the application of wheat straw autohydrolysis liquor

The xylanase biosynthesis is induced by its substrate—xylan. The high xylan content in some wastes such as wheat residues (wheat bran and wheat straw) makes them accessible and cheap sources of inducers to be mainly applied in great volumes of fermentation, such as those of industrial bioreactors. Thus, in this work, the main proposal was incorporated in the nutrient medium wheat straw particles decomposed to soluble compounds (liquor) through treatment of lignocellulosic materials in autohydrolysis process, as a strategy to increase and undervalue xylanase production by Aspergillus ochraceus. The wheat straw autohydrolysis liquor produced in several conditions was used as a sole carbon source or with wheat bran. The best conditions for xylanase and β-xylosidase production were observed when A. ochraceus was cultivated with 1% wheat bran added of 10% wheat straw liquor (produced after 15 min of hydrothermal treatment) as carbon source. This substrate was more favorable when compared with xylan, wheat bran, and wheat straw autohydrolysis liquor used separately. The application of this substrate mixture in a stirred tank bioreactor indicated the possibility of scaling up the process to commercial production.This work was supported by Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP/Brazil), Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq/Brazil), National System for Research on Biodiversity (SISBIOTA-Brazil, CNPq 563260/2010-6/FAPESP no. 2010/52322-3), and Fundacao para a Ciencia e a Tecnologia (FCT/Portugal)