2,675 research outputs found

    Development of a co-cured composite torque shaft for rudder of high speed aircraft

    Get PDF
    The Carbon Fibre reinforced Composites are widely used in developing various composite parts of civil and13; military aircraft due to its high specific strength and specific stiffness. Rudder being a primary control surface in an aircraft, it is subjected to various loads and needs high degree of structural integrity. Usually rudders are made of metal with many fasteners. In NAL we have designed and developed a composite rudder. Specialty of this13; rudder is that it has a torque shaft made up of carbon composite and has only few rivets. Conventionally torque13; shaft s are made up of special metals like titanium. The objective of this paper is to highlight the development of13; various tooling techniques used to fabricate the composite torque shaft . All major parts of the torque shaft are13; made by Co-curing technique and the metal attachments are embedded to the composite parts by self locking13; mechanism design. To qualify the torque shaft fatigue tests are done and ageing studies performed to prove13; structural integrity of the torque shaft under extreme environmental conditions. This paper portrays the13; development efforts, tolling and fabrication approaches for successful realization of the CFRP Torque Shaft

    Indigenous Traditional Method for Making Liquid Detergent “Chhoa” from Zea mays Linn. in Shivalik Hills (Himachal Pradesh), India

    Get PDF
    In the past, herbal liquid detergent was in regular use but with modernization this traditional indigenous knowledge depleted and at present is in use to a limited extent in some rural pockets of Shivalik hills. Dried maize (Zea mays Linn.) stems are burnt to ash and are put into a bamboo basket with a bottom layer of paddy straw. After pouring boiling water over ash, herbal liquid detergent is obtained as a final product. It is eco-friendly and a classic example of sustainability concept

    Technical Note: Detecting and Subcategorizing Hard-coding Errors in Bioenergy-relevant Spreadsheets Using Visual Basic for Applications (VBA)

    Get PDF
    Electronic spreadsheets play an indispensable role in the simulation, modeling, and analysis of bioenergy systems, and their results have the ability to affect decision-making significantly. Prior research has shown that spreadsheets are highly error-prone, and that a large percentage of these errors are difficult to detect. To that end, we developed computer code (implemented in Visual Basic for Applications, running under Microsoft Excel) to detect a particularly insidious form of spreadsheet error: the hard-coding error. These errors are defined as the presence of one or more unreferenced numerical values in a cell formula. The code was used to audit six engineering spreadsheets relevant to bioenergy systems, three developed in our lab (and reported on in other sessions at the AIM), and three in the public domain. The preliminary audit results were analyzed to understand the nature and distribution of hard-coding errors. The preponderance and diversity of hard-coding errors in these spreadsheets motivated us to subcategorize them. Together, the hard-coding error detection program and sub-categorization program provide a robust and rapid means of detecting and categorizing multiple types of hard-coding errors. Use of these programs could increase the reliability of spreadsheet software used in simulation, modeling, and analysis of bioenergy systems

    Detecting and categorizing hard-coding errors in Excel Spreadsheets using Visual Basic for Applications (VBA)

    Get PDF
    Electronic spreadsheets play an indispensable role in the simulation, modeling, and analysis of bioenergy systems, and their results have the ability to affect decision-making significantly. Prior research has shown that spreadsheets are highly error-prone, and that a large percentage of these errors are difficult to detect. To that end, we developed computer code (implemented in Visual Basic for Applications, running under Microsoft Excel) to detect a particularly insidious form of spreadsheet error: the hard-coding error. These errors are defined as the presence of one or more unreferenced numerical values in a cell formula. Hard-coding errors are dangerous because they are a likely source of erroneous constants and/or non-updating assumptions. The code was used to audit six spreadsheets relevant to bioenergy systems, three developed in our lab (and reported on in other sessions at the AIM), and three in the public domain. The preliminary audit results were analyzed to understand the nature and distribution of hard-coding errors. The preponderance and diversity of hard-coding errors in these spreadsheets motivated us to subcategorize them. Together, the hard-coding error detection program and sub-categorization program provide a robust and rapid means of detecting and categorizing multiple types of hard-coding errors. Use of these programs could increase the reliability of spreadsheet software used in simulation, modeling, and analysis of bioenergy systems

    Ethnobotanical Studies on Timber Resources of Himachal Pradesh (H.P.), India

    Get PDF
    Timber is one of the most important resources in the life of ethnic communities and villagers. Timber resources are used by the ethnic communities and the villagers for various purposes i.e. house construction, furniture, and agricultural implements; for making walking sticks, musical instruments and packing cases etc. Timber is the most important forest resource along with shelter, food and clothes used by any community in Himachal Pradesh as well as in any part of the country and it has contributed a lot in the development of various civilizations from time immortal. This paper deals with the 61 timber resources of H.P. belonging to 47 genera and 26 families as well as their various uses by the ethnic communities and villagers. The timber resources have been divided in all the three ranges of ‘Himachal Himalayas’

    Magnetoresistance behavior of a ferromagnetic shape memory alloy: Ni_1.75Mn_1.25Ga

    Full text link
    A negative-positive-negative switching behavior of magnetoresistance (MR) with temperature is observed in a ferromagnetic shape memory alloy Ni_1.75Mn_1.25Ga. In the austenitic phase between 300 and 120 K, MR is negative due to s-d scattering. Curiously, below 120K MR is positive, while at still lower temperatures in the martensitic phase, MR is negative again. The positive MR cannot be explained by Lorentz contribution and is related to a magnetic transition. Evidence for this is obtained from ab initio density functional theory, a decrease in magnetization and resistivity upturn at 120 K. Theory shows that a ferrimagnetic state with anti-ferromagnetic alignment between the local magnetic moments of the Mn atoms is the energetically favoured ground state. In the martensitic phase, there are two competing factors that govern the MR behavior: a dominant negative trend up to the saturation field due to the decrease of electron scattering at twin and domain boundaries; and a weaker positive trend due to the ferrimagnetic nature of the magnetic state. MR exhibits a hysteresis between heating and cooling that is related to the first order nature of the martensitic phase transition.Comment: 17 pages, 5 figures. Accepted in Phys. Rev.

    IMAGES II. A surprisingly low fraction of undisturbed rotating spiral disks at z~0.6: The morpho-kinematical relation 6 Gyrs ago

    Full text link
    We present a first combined analysis of the morphological and dynamical properties for the Intermediate MAss Galaxy Evolution Sequence (IMAGES) sample. It is a representative sample of 52 z~0.6 galaxies with Mstell from 1.5 to 15 10^10Msun and possessing 3D resolved kinematics and HST deep imaging in at least two broad band filters. We aim at evaluate robustly the evolution of rotating spirals since z~0.6, as well as to test the different schemes for classifying galaxies morphologically. We used all the information provided by multi-band images, color maps and 2 dimensional light fitting to assign to each object a morphological class. We divided our sample between spiral disks, peculiar objects, compact objects and mergers. Using our morphological classification scheme, 4/5 of identified spirals are rotating disks and more than 4/5 of identified peculiar galaxies show complex kinematics, while automatic classification methods such as Concentration-Asymmetry and GINI-M20 severely overestimate the fraction of relaxed disk galaxies. Using this methodology, we find that the fraction of rotating spirals has increased by a factor ~ 2 during the last 6 Gyrs, a much higher fraction that found previously based on morphologies alone. These rotating spiral disks are forming stars very rapidly, doubling their stellar masses over the last 6 Gyrs, while most of their stars have been formed few Gyrs earlier, which reveals the presence of a large gas supply. Because they are likely the progenitors of local spirals, we can conjecture how their properties are evolving. Their disks show some evidence for an inside-out growth and the gas supply/accretion is not made randomly as the disk need to be stable in order to match the local disk properties.Comment: Typos corrected, reference adde

    Quaternion Octonion Reformulation of Quantum Chromodynamics

    Full text link
    We have made an attempt to develop the quaternionic formulation of Yang - Mill's field equations and octonion reformulation of quantum chromo dynamics (QCD). Starting with the Lagrangian density, we have discussed the field equations of SU(2) and SU(3) gauge fields for both cases of global and local gauge symmetries. It has been shown that the three quaternion units explain the structure of Yang- Mill's field while the seven octonion units provide the consistent structure of SU(3)_{C} gauge symmetry of quantum chromo dynamics
    corecore