Multi-purpose controllable function generator

This paper deals with the design and implementation of a new multi-purpose function generator, in which the frequency of oscillation can be controlled by an external signal. It provides different types of waveforms such as sine, square, triangle, TTL square and monitor waveforms. The TTL square and monitor waveforms are provided for use respectively as a clock to logic circuits and for various timebase applications. The function generator provides low-distortion outputs from 1 MHz to 1 MHz in nine controlled ranges. The output waveforms are calibrated 0-20 V pk-pk with DC offset control. Input and output impedances are 10Ω and 600Ω, respectively.     

Fast-reading DVM with real-time autocalibration

The voltmeter described gives high accuracy and stability at reduced cost and with simplified calibration. It measures direct and alternating voltages and resistance. Under programmed control, it can make 25 direct-voltage readings per second with 5½ digit resolution. Alternating-voltage readings are made at a rate of 13 per second, also under programmed control. The true-RMS converter has a frequency range of 0–8 MHz, a crest factor of 10: 1, and AC and DC capability. The voltmeter calibrates itself by accounting automatically for gain and offset errors.     

Dendrite morphology of several steady state unidirectionally solidified iron base alloys

The experimental data are presented of the dendrite morphology of steady state unidirectionally solidified steels. The dendrite arm spacings were correlated with the equation A =KR ^mG^mwhereR is the growth rate and G the temperature gradient. The exponentsm andn for the primary arms are fairly close to the theoretical values (m = -0.25,n = -0.5). For the secondary arms they are about the same (-0.4). The primary arm spacings do not depend much on composition. The secondary arm spacings, however, decrease at fixed carbon content with increasing content of substitutional elements, and they were found to be smaller in a steel freezing as ferrite compared to steels freezing as austenite. All the authors were with Max-Planck Institut für Eisenforschung, 4 Düsseldorf 1, Max-Planck-Str. 1, Germany, at the time this investigation was carried out.     

A proposed method to reconstruct the three‐dimensional dispersion profile of polymeric fibres based on variable wavelength interferometry

In this paper, we suggest a modification to the conventional variable wavelength interferometry. This modification allowed us to calculate the dispersion curve of each point inside polymeric fibres instead of calculating the mean dispersion of these fibres. This modified mathematical treatment was used to calculate the three‐dimensional dispersion profile of isotactic polypropylene fibres suffering from necking deformation. The different steps of calculating the three‐dimensional dispersion profile of the fibre were demonstrated. The application of this modified method revealed the variation of the fibre material dispersion before, inside and after the necking region. In addition, the birefringence profile of the necked isotactic polypropylene was determined using the proposed mathematical treatment. This allowed us to diagnose the interaction of the incident waves with necked polypropylene fibres, which gives extensive information on the orientation of the molecular chains during the formation of the necking phenomenon.     

A novel double‐image Fizeau system for accurate investigation of anisotropic polymer fibres

This paper introduces a double‐image multiple‐beam Fizeau fringes system. The introduced system can dynamically determine the variations of the refractive indices for both parallel and perpendicular polarization simultaneously. This is achieved by the simultaneous capturing of two multiple‐beam interference patterns during the mechanical processing of isotactic polypropylene fibre. This parallel determination of the refractive indices of both polarization directions allowed us to determine the full‐field distribution of the stress vector, S . To accomplish this, a mathematical model was deduced to calculate the components of the stress vector, S , i.e. parallel stress component, S₁, and perpendicular stress component, S₂. Double‐image Fizeau fringes system and the deduced mathematical model were used to investigate the variation of the refractive index and stress components of the fibre during the stretching process and propagation of necked regions.     

Gene expression of 49 kDa apyrase,cytoskeletal proteins,ATPase, ADPase and amino acid contents of <i>Pisum sativum</i> (L.) cells germinated in E<i>uryops arabicus</i> (Steud. ex Jaub. & Spach) water extract

The present research reports of quick and marked changes induced by plant extract of Euryops arabicus in the gene expression of 49-kDa apyrases, cytoskeletal proteins, ATPases, ADPase and amount of amino acid of pea (Pisum sativum L. var. Alaska). Pellets of cytoskeletals proteins (27000 xg) were probed with anti-apyrase antibody, biotinylated anti-rat, actin and alpha and beta-tubulin for Western blotting. ATPase and ADPase activities were determined based on the hydrolytic efficacy of adenine triphosphate and adenine diphosphate. By 72 hours, the abundance of apyrases, cytoskeletal proteins and amount of amino acid in pellets of 27000 xg of germinated pea seeds in E. arabicus extracts were sharply increased than those sown in distilled water. All the samples exhibited that the stems had more amount from apyrases, cytoskeletal proteins, amino acids and ATPase and ADPase activities than primary leaves and primary roots that were germinated either on E. arabicus water extract or in distilled water. Based on the enzyme’s capability to hydrolyse nucleotide triphosphate and nucleotide diphosphate as well as the direct association between expression of 49-kDa apyrase and cytoskeletal proteins, E. arabicus water extract had an important effect on plant germinations.     

Modelling,structural, thermal,optical and vibrational studies of a new organic–inorganic hybrid material (C<Subscript>5</Subscript>H<Subscript>16</Subscript>N<Subscript>2</Subscript>)Cd<Subscript>1.5</Subscript>Cl<Subscript>5</Subscript>

Chemical preparation, theoretical calculations, X-ray single-crystal diffraction, thermal analysis, electrochemical measurements, IR, Raman and UV spectroscopic investigations of a novel organic–inorganic hybrid material (C₅H₁₆N₂)Cd_1.5Cl₅ are described. The structure provides a new interesting example of infinite inorganic chains of [Cd_1.5Cl₅]\(_{\mathbf {n}}^{\boldsymbol {2\mathrm {n}-}}\) following the a crystallographic direction. The [Cd_1.5Cl₅]^2? anions are interconnected by N–H ? Cl hydrogen bonds. The Hirshfeld surface and associated fingerprint plots of the compound are presented to explore the nature of intermolecular interactions and their relative contributions in building the solid-state architecture. IR and Raman spectra are reported and discussed on the basis of group theoretical analysis and quantum chemical density functional theory (DFT) calculation. The molecular HOMO–LUMO compositions and their respective energy gaps are also drawn to explain the activity of our compound. Thermal analysis reveals the anhydrous character of the compound.     

Chaos generator for secure transmission using a sine map and an RLC series circuit

This paper deals with the model analysis of a chaos generator for secure transmission. In this proposed system discrete value signals and continuous value signals are used together and are interacting one another. The main advantage of this system is that a discrete chaotic map can be implemented in the digital circuit with many parameters, and initial condition can be set with a great accuracy. Also, the problem of periodicity which is always encountered in any fully discrete systems can be avoided. A chao...     

A novel method for identifying the order of interference using phase‐shifting digital holography

In this paper, we introduced a mathematical method for measuring the optical path length differences (OPDs), which is suitable for large OPD values where the fringes connections are difficult to detect. The proposed method is based on varying the width of the fringes, without changing the wavelength of the used coherent source. Also, in this work, we discussed the need for such method in off‐axis phase‐shifting digital holography. Low‐resolution off‐axis holograms failed to detect the correct interference order. In general, off‐axis phase‐shifting digital holography is limited by the resolution of the captured holograms. The results obtained using our proposed technique were compared to the results obtained using off‐axis phase‐shifting digital holograms and conventional two‐beam interferometry. Holograms were given for illustration.