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  • 1
    Language: English
    In: Polymer, 2011, Vol.52(25), pp.5795-5802
    Description: Optically active polyorthoanisidine, polyorthotoluidine, polyorthoethylaniline and polyorthochloroaniline were synthesized with chemical polymerization of corresponding monomers in aqueous medium by using - or -camphorsulfonic acid ( - or -CSA) as chiral dopant, ammonium persulfate as oxidant, and diaminodiphenylamine as initiator. By circular dichroism spectroscopic measurements, it was found that PANI exhibited generally a reversed chirality in comparison with the used chiral dopant, but the substituted PANIs had the same one as the chiral dopant. This revealed that the substituent at ortho position caused helical inversion of conformation in comparison with the parent PANI. Such effect was further confirmed by the influence of the copolymerization of aniline and its derivatives on the chirality of the copolymers. The effect of the substituent on the chirality of the copolymers was increased with the increase of the steric hindrance of the ortho substituent. A mechanism was proposed to explain the effects of steric hindrance on the chirality of PANIs. The clarified relationship between the steric hindrance and the chirality of the polymer can enable us to tailor the chiroptical properties of functional polymer materials for future application.
    Keywords: Chirality ; Polyaniline Nanofibers ; Steric Hindrance ; Engineering ; Chemistry
    ISSN: 0032-3861
    E-ISSN: 1873-2291
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  • 2
    Language: English
    In: Journal of Alloys and Compounds, 15 January 2017, Vol.691, pp.489-497
    Description: Gamma titanium aluminides are promising alloys known for their good mechanical properties and low densities, but their low oxidation resistance at high temperatures limits their application. This work discusses the thermocyclic oxidation behavior of newly developed β/γ-TiAl alloys at temperatures between 600 °C and 900 °C. An influence of β-stabilizing alloying elements like Nb and V on the oxidation of these alloys has been investigated here. The selected alloys are tested in an in-house developed thermocyclic furnace. The oxidation study is supported by gravimetric measurements along with Scanning Electron Microscopy (SEM) and Electron Diffraction Spectroscopy (EDS) mapping of the oxide layers. Additionally, phase formation after oxidation has been determined using X-Ray Diffraction (XRD). Results show that the Nb containing alloys are more oxidation resistant as compared to V containing alloys. The formation of a mixture of Al O and TiO layers was found for all the alloys. Additionally, the oxide kinetics controlled the oxide growth and formation of various phases at different testing temperatures.
    Keywords: Γ-Tial ; Thermocyclic Oxidation ; Β-Stabilizing Elements ; Aluminum Oxide ; Titanium Oxide ; Engineering ; Chemistry ; Physics
    ISSN: 0925-8388
    E-ISSN: 1873-4669
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  • 3
    Language: English
    In: Pakistan Journal of Zoology, April 30, 2011, Vol.43(2)
    Description: Cotton strains having different hair length and density were evaluated for tolerance to Bemisia tabaci, Amrasca devastans and Thrips tabaci, and survival of predators and parasitoids. The seed treatment effect on the population of these insect pests and natural enemies were also studied. Population of B. tabaci was higher on the strain Cyto-46, having trichome density of 474 plus or minus 12.9 per cm2 and hair length of 705 plus or minus 44.8 microns and minimum on strain Cyto-12/91, having trichome density of 1011 plus or minus 21.0 per cm2 and hair length of 644 plus or minus 27.3 mu . However, A. devastans was significantly higher on strain Cyto-12/91 whereas, thrips remained significantly less on the same strain Cyto-12/91. the total number of predators were significantly higher on strains having greater than600 trichomes per cm2 whereas the level of parasitism remained the same on all the strains. Seed treatment proved effective against A. devastans only. However, the number of predators and percent parasitism was not significantly affected by the seed treatment. Present study revealed that the early season sucking pest complex can be managed by choosing the variety having moderate leaf hair density and if variety choice is limited then the early season sucking pest especially jassid could be managed effectively by the seed treatment.
    Keywords: Whiteflies -- Food And Nutrition ; Cotton (Plant) -- Genetic Aspects ; Cotton (Plant) -- Physiological Aspects ; Insect Pests -- Food And Nutrition ; Predation (Biology) -- Research ; Parasitism -- Research
    ISSN: 0030-9923
    Source: Cengage Learning, Inc.
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  • 4
    Language: English
    In: International Journal of Agriculture and Biology, June 30, 2015, Vol.17(3)
    Description: Biological preparation containing live or latent cells of microorganisms or their metabolites, which when inoculated to seed, soil or roots of seedlings, promote plant growth and enhance harvestable yield is termed as biofertilizer. Biofertilizers, generally marketed, contain microbes capable of nitrogen (N) -fixation, phosphate solubilization/mineralization, phytohormone production and biocontrol. This paper reviews various initiatives in research and development of the biofertilizers taken by different institutes of Pakistan. The use of biofertilizers can play an important role in sustaining the agriculture systems. In Pakistan, where fertilizer is annually a hundred billion rupees business, even a 10% contribution by biofertilizer can save rupees ~10 billion. Various research groups/organizations are engaged in research and development on biofertilizers and have made their efforts to increase the application of biofertilizers in Pakistan's agriculture. Inconsistent field performance, lack of regulation and standards, quality issues of the product(s), awareness and lack of publicity are the major constraints in the widespread use of biofertilizers in Pakistan. If these problems are resolved, better results and responses can be expected through biofertilizer use in Pakistan. Assuring quality of products with extensive field-based testing, capacity building of resource persons and stakeholders on standard production processes, storage and application will help a wider adoption and popularization of the biofertilizer technologies. Copyright 2015 Friends Science Publishers
    Keywords: Fertilizers – Usage ; Fertilizers – Properties
    ISSN: 1560-8530
    E-ISSN: 18149596
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  • 5
    Language: English
    In: The Journal of the Acoustical Society of America, June 2018, Vol.143(6), pp.3873
    Description: This paper proposes efficient algorithms for accurate recovery of direction-of-arrivals (DoAs) of sources from single-snapshot measurements using compressed beamforming (CBF). In CBF, the conventional sensor array signal model is cast as an underdetermined complex-valued linear regression model and sparse signal recovery methods are used for solving the DoA finding problem. A complex-valued pathwise weighted elastic net (c-PW-WEN) algorithm is developed that finds solutions at the knots of penalty parameter values over a path (or grid) of elastic net (EN) tuning parameter values. c-PW-WEN also computes least absolute shrinkage and selection operator (LASSO) or weighted LASSO in its path. A sequential adaptive EN (SAEN) method is then proposed that is based on c-PW-WEN algorithm with adaptive weights that depend on previous solution. Extensive simulation studies illustrate that SAEN improves the probability of exact recovery of true support compared to conventional sparse signal recovery approaches such as LASSO, EN, or orthogonal matching pursuit in several challenging multiple target scenarios. The effectiveness of SAEN is more pronounced in the presence of high mutual coherence.
    Keywords: Special Issue On Compressive Sensing In Acoustics;
    ISSN: 00014966
    E-ISSN: 1520-8524
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  • 6
    Language: English
    In: Journal of Behavioural Sciences, Dec 31, 2012, Vol.22(2)
    Keywords: Decision Making -- Psychological Aspects ; College Students -- Psychological Aspects ; Personality Types -- Influence
    ISSN: 1028-9097
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  • 7
    Language: English
    In: Pakistan Journal of Psychology, June 30, 2012, Vol.43(1)
    Keywords: Conflict Management -- Laws, Regulations And Rules ; Conflict Management -- Analysis ; Emotional Intelligence -- Analysis
    ISSN: 0030-9869
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  • 8
    Language: English
    In: Journal of the Franklin Institute, March 2014, Vol.351(3), pp.1657-1672
    Description: Mathematical models are an approximate of physical systems and design procedures are only complete when modeling errors have been quantified. Uncertainties are incorporated in design procedure to compensate such discrepancies and to add robustness. This paper investigates the design problem of for polytopic uncertain switched systems. State-space model is considered subject to time-varying uncertainties, and designated observer gains ensuring stability of overall system are also parameter-dependent. Synthesis procedure is demonstrated by employing performance criteria which has become a standard for robust system design against external disturbances. This investigation is carried out in the framework of (FTS) and (FTB) which is the focus of researchers recently because of its apparent practical significance, especially after the emergent utilization of linear matrix inequalities.
    Keywords: Engineering
    ISSN: 0016-0032
    E-ISSN: 1879-2693
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  • 9
    Language: English
    In: Sarhad Journal of Agriculture, March 31, 2013, Vol.29(1)
    Description: AES (Advanced Encryption Standard) is state of the art symmetric cipher. This study illustrates a new approach to low cost and efficient implementation of AES cipher on 8 bit microprocessors. This crypto processor implementation is recommended for low speed applications where cost, availability and ease of developing and manufacturing comes in. Most efficient possible implementation of Galois field multiplication and key expansion on 8 bit microprocessors is demonstrated. Decryption algorithm is modified for two way communication without any overhead. Two modes of operations are considered, Electronic Codebook and Counter mode. Counter mode is further optimized for lowest latency due to its pre-processing feature.
    Keywords: Algorithms -- Economic Aspects
    ISSN: 1016-4383
    Source: Cengage Learning, Inc.
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  • 10
    Language: English
    In: Journal of the Chemical Society of Pakistan, Dec 31, 2013, Vol.35(6)
    Keywords: Antianxiety Agents -- Analysis ; Phenobarbital -- Analysis ; Antidepressants -- Analysis ; Sleep -- Analysis
    ISSN: 0253-5106
    Source: Cengage Learning, Inc.
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