299 research outputs found
A Cd(ii) based metal organic framework: a photosensitive current conductor
No full textA novel cadmium( II ) based metal organic framework, [Cd(3-bpd)(SCN) 2 ] n (1) where 3-bpd = 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene has been synthesized and characterized by elemental analysis, various spectroscopic techniques, TGA and single crystal X-ray diffraction analysis. X-ray analysis shows the formation of an undulated polymeric two-dimensional network parallel to the (0 −1 1) plane. Current conduction properties of 1 have been explored in the dark and in the presence of light. The study shows that current conduction of the complex increases with the increase of the incident light intensity. On progression of intensity of glancing radiation the photosensitivity of 1 has been increased. The time dependent light response on charge carrier conduction reveals that complex 1 may uncover new ground to explore in optoelectronic switching applications
Photo-responsive Schottky Diode Behavior of a Donor-Acceptor Co-crystal with Violet Blue Light Emission
No full textHerein, we report the crystal structure, supramolecular structure, electronic
transport property and optoelectronic behaviour of a co-crystal made of
tetrabromoterephthalic acid (TBTA) and quinoxaline (QUIN) (1:1). The sample has been
characterized by thermogravimetric analysis and spectral techniques. Moreover, the
theoretical analysis on noncovalent interactions, optical properties and band structure of the
co-crystal has been performed. The co-crystal has been crystallized in orthorhombic system
with P nma space group and the constituent molecules assemble in the solid state by using O-
H···N hydrogen bonding, π···π, Br···π and Br···O interactions. The ground state geometry
optimization over the hydrogen bonded dimer by DFT method indicates that TBTA acts as
the donor and QUIN as the acceptor within the self-assembled co-crystal. According to UV-
vis spectroscopic study the bandgap of the co-crystal is ~ 3.18 eV. In solid state it exhibits a
broad emission band with maxima at 405 nm while in aqueous medium its
photoluminescence emission peaks are obtained at 350 and 403 nm. The values of average
fluorescence lifetime of the sample in aqueous medium are 3.38 ns at 352 nm and 4.94 ns at
403 nm. Under UV-irradiation, the co-crystal emits violet-blue light. The emission spectra in
solution phase shows relative quantum yield of 0.018. Band structure calculation indicates
that the co-crystal is a p-type semiconductor with bandgap of 2.835 eV. Due to its
semiconducting character, the ITO/Co-crystal/Al sandwiched structured device acts as a Schottky barrier diode with rectification ratio, ideality factor, barrier height and series
resistance of 41, 1.36, 0.70 eV, and 26.97 KΩ, respectively. The current through the device
increases substantially under visible light exposure. Upon visible light illumination the values
of electrical conductivity, mobility, carrier concentration increases by 35 (± 0.5), 54 (± 0.5)
and 6 (± 0.5) %, respectively, with respect to dark condition. It has been shown that π···π and
hydrogen bonding interaction can play crucial role in producing donor-acceptor (D-A) type
co-crystal, semiconducting behaviour can be incorporated in organic co-crystal utilizing π···π
and hydrogen bonding interactions and weak intermolecular π···π, Br···π and Br···O
interactions can act as the pathway for electrical conduction
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MicroMI: a portable microbiological mobile incubator that uses inexpensive lithium power banks for field microbiology
Get PDFIncubation at controlled temperature is a key step in culture based microbiological tests. Access to culture-based microbiological testing requires access to conventional incubators in a laboratory. Portable incubators allow microbiological testing in the field and in resource-limited settings, and can eliminate the challenge of sample transportation, minimising the chance of sample degradation. Recent studies have reported low-cost portable incubator designs suitable for field or off-grid use, but these either need an external power supply (e.g. mains AC or 12 V DC), or rely on passive heating without thermostatic control. Here we report that small inexpensive uninterruptable power supply (UPS) products manufactured for consumer electronics and powered by lithium-ion battery packs allowing thermostatic temperature control in small portable incubators that can maintain precise temperatures with or without external power. We present an open-source design for a Microbiological Mobile Incubator (MicroMI) in two sizes for field use. The MicroMI is built from simple and widely available components and is easy to set up. The open source design can be customised for different numbers of samples. The smallest and most efficient design uses a vacuum insulated food flask that allows longer operation with smaller, lower capacity UPS. The larger flight case design has space for more samples, but depletes the battery faster. The UPS maintains a typical microbiology incubation temperature for up to 24 h without external power- ideal for typical incubation needed for culture methods. The battery capacity, incubator design, and external ambient temperature all affected duration of operation without requiring external power. We validated the MicroMI by conducting classical microbiological tests using agar petri dishes, slant cultures and dip slides, and biochemical tests. We conclude the MicroMI design allows inexpensive lithium battery products to be used to simplify field microbiology and increase access to vital analytical microbiology testing
Crystal and mesophase structure of a bicyclohexyl cyano mesogen
No full text: The phase behaviour of 4-[trans-4-(trans-4-propylcyclohexyl)cyclohexyl]benzonitrile, C22H31N, 1, has been examined. This compound has two different solid phases, denoted I and II, and exhibits thermotropic liquid-crystalline behaviour, with a remarkable interval of stability of the mesophase between the lower melting solid phase (75 °C) and the isotropization temperature (247 °C). The crystal and molecular structures of solid phase I have been determined at 173 K. The cyclohexyl rings both adopt the chair conformation and are equatorially substituted. The packing of 1 in the crystalline state is driven by the antiparallel arrangement of cyano dipoles with the formation of close contacts involving the strong cyano acceptor and weak aromatic C-H or aliphatic C-H donors. The crystal packing is discussed and compared with X-ray diffraction data in the liquid-crystalline state. The combination of thermal analysis, optical polarizing microscopy and X-ray diffraction analysis suggests that the mesophase is a partially ordered smectic phase. The lamellar structure of the mesophase is retained in crystalline solid phase II obtained by cooling the liquid-crystalline phase
Physical verification as administrative and collection evaluation tool: A study ofInstitute of Agriculture Library; Visva-Bharati
Get PDFThis article is the result of an intensive stock verification of more than 50000 documents of an academic library(Institute of Agriculture; Visva-Bharati) established in 1957. The physical verification process includes physical noting of all accession number of books on and out of stack and use of LibSys software to generate reports. The paper highlights that physical verification of collection can help in identifying major areas of loss and thereby can help in framing administrative guideline for collection evaluation and management policy. The paper also urges for review of existing government rules regarding the loss of books and weed-out policy
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Gasping for harmony communication between arbitrary clock domains with multiple voltage domains using a locally-clocked, linear dual-clock FIFO scheme
Get PDFCMOS scaling has resulted in miniaturized high speed and high density system on a chip (SoC) designs. The desired high performance systems introduce a number of design challenges including increasing power dissipation, longer delays in transmitting signals between communicating Intellectual Property (IP) blocks and difficulties in synchronizing the IPs block with a single clock source. Consequently, these IP blocks may operate from independent clocks, creating multiple clock domains in a SoC, further complicating synchronization. Advanced power management systems dynamically change the supply voltages for these SoCs to reduce power consumption, changing device characteristics and further exacerbating communication challenges. In this dissertation, a communication scheme is presented that addresses some of these challenges and is compared to an existing scheme. The proposed FIFO scheme uses locally-generated clock signals to control data propagation along a communication channel, providing independence from a global clock while significantly improving throughput. The control logic enables the proposed scheme to perform synchronization between two arbitrary clocks using one or more stages. The proposed scheme operates up to 9.5 giga-samples per second per channel, synchronizes at sub-threshold levels, and when compared to a reference scheme dissipates 82% less power and has a speed-up of 58%
Publication of Tagore’s song offerings, the <i style="mso-bidi-font-style:normal">Gitanjali </i>: A Study
No full text15-21Before establishment of Visva Bharati
Granthan Vibhaga (VBGV) in 1923, Rabindranath Tagore’s writings were published
by his friends and family members and Adi Brahmasamaj Jantra (Press of
Brahmasamaj, Calcutta).
Rabindranath (1861-1941) received the Nobel Prize for <i style="mso-bidi-font-style:
normal">Gitanjali (Song Offerings) in 1913 which is a collection of poems
from different kavyagrantha (book of poems). Copyright of Rabindranath Tagore’s
works given to Visva-Bharati expired in December 2001. Private publishers have
been free to publish the writings of Rabindranath Tagore since then. The
present paper is an attempt to assess the quality of publication of Gitanjali published by private
publishers before establishment of VBGV and after expiry of copyright. It is
observed that a small portion of Bengali publishers are publishing Gitanjali at a lower price but with good
number of mistakes. Pre-VBGV publications also have mistakes
Ray's Scheme: Graphical Password Based Hybrid Authentication System for Smart Hand Held Devices
Get PDFPasswords provide security mechanism for authentication and protection services against unwanted access to resources. One promising alternatives of textual passwords is a graphical based password. According to human psychology, human can easily remember pictures. In this paper, I have proposed a new hybrid graphical password based system. The system is a combination of recognition and pure recall based techniques and that offers many advantages over the existing systems and may be more convenient for the user. My approach is resistant to shoulder surfing attack and many other attacks on graphical passwords. This scheme is proposed for smart hand held devices (like smart phones i.e. PDAs, ipod, iphone, etc) which are more handy and convenient to use than traditional desktop computer systems. Keywords: smart phones, graphical passwords, authentication, network securit
Influence of Manu on Ranganthan's philosophy of library science: An overview
No full text213-216<span style="font-size:11.0pt;font-family:
" times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-bidi-font-family:="" mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:="" hi"="" lang="EN-GB">Shiyali Ramamrita Ranganathan introduced a number of classical theories and
their practical applications with rules, regulations, laws, canons etc. The
article traces the influencing philosophical factor which laid the
philosophical foundation in his mind for lifelong academic and professional
efforts. It is observed that Indian classical epic literature in general and
Laws of Manu known as Manu Samhita or <i style="mso-bidi-font-style:
normal">Manu-smriti in particular had a great impact on his thoughts.</span
Internet of Things based smart measurement and monitoring of wood Equilibrium Moisture Content
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