Noise characteristics of upper surface blown configurations: Analytical Studies

Noise and flow results of upper surface blown configurations were analyzed. The dominant noise source mechanisms were identified from experimental data. From far-field noise data for various geometric and operational parameters, an empirical noise prediction program was developed and evaluated by comparing predicted results with experimental data from other tests. USB aircraft compatibility studies were conducted using the described noise prediction and a cruise performance data base. A final design aircraft was selected and theory was developed for the noise from the trailing edge wake assuming it as a highly sheared layer

Dynamic analysis of a pre-and-post ice impacted blade

The dynamic characteristics of an engine blade are evaluated under pre-and-post ice impact conditions using the NASA in-house computer code BLASIM. The ice impacts the leading edge of the blade causing severe local damage. The local structural response of the blade due to the ice impact is predicted via a transient response analysis by modeling only a local patch around the impact region. After ice impact, the global geometry of the blade is updated using deformations of the local patch and a free vibration analysis is performed. The effects of ice impact location, size and ice velocity on the blade mode shapes and natural frequencies are investigated. The results indicate that basic nature of the mode shapes remains unchanged after impact and that the maximum variation in natural frequencies occurs for the twisting mode of the blade

Propfan Test Assessment (PTA): Flight test report

The Propfan Test Assessment (PTA) aircraft was flown to obtain glade stress and noise data for a 2.74m (9 ft.) diameter single rotation propfan. Tests were performed at Mach numbers to 0.85 and altitudes to 12,192m (40,000 ft.). The propfan was well-behaved structurally over the entire flight envelope, demonstrating that the blade design technology was completely adequate. Noise data were characterized by strong signals at blade passage frequency and up to 10 harmonics. Cabin noise was not so high as to preclude attainment of comfortable levels with suitable wall treatment. Community noise was not excessive

Structural tailoring of aircraft engine blade subject to ice impact constraints

Results are presented for the minimum weight design of SR2 unswept blade made of (titanium/graphite-epoxy/titanium) sub s fiber composite. The blade which is rotating at high RPM is subject to ice impact. The root chord length, blade thicknesses at five stations, and graphite-epoxy ply orientation are chosen as design variables. Design constraints are placed on the behavior variables: local leading edge strain and root damage parameter (combined stress failure criteria) as a function due to ice impact, maximum spanwise centrifugal stress at the root of the deformed blade due to local damage, first three natural frequencies, and resonance margin after impact. The method of feasible directions is employed to solve the inequality constrained minimization problem. The effect of ice speed and the ice impact location on the final design are discussed

Root damage analysis of aircraft engine blade subject to ice impact

The blade root response due to ice impact on an engine blade is simulated using the NASA in-house code BLASIM. The ice piece is modeled as an equivalent spherical object impacting on the leading edge of the blade and has the velocity opposite to that of the aircraft with direction parallel to the engine axis. The effect of ice impact is considered to be an impulse load on the blade with its amplitude computed based on the momentum transfer principle. The blade response due to the impact is carried out by modal superposition using the first three modes. The maximum dynamic stresses at the blade root are computed at the quarter cycle of the first natural frequency. A combined stress failure function based on modified distortion energy is used to study the spanwise bending damage response at the blade root. That damage function reaches maximum value for very low ice speeds and increases steeply with increases in engine speed

A modified sensitive palladium-copper oxide and multiwalled carbon nanotubes electrochemical sensor for detection of ametridione pesticide

Glassy carbon electrode modified sensitive Pd-CuO/MWCNTs electrochemical nanosensor was used for detection of ametridione pesticide in water samples. The morphology characteristics of Pd-CuO/MWCNTs are examined by scanning electron microscopy and EDX. The ametridione pesticide under voltammetric investigation involves irreversible, 4e? electron reduction based on the protonation of the two carbonyl groups (>C=O). The voltammetric method was applied for the detection of ametridione in BR buffer solution at pH 5.0 as a supporting electrolyte. The detection limit, limit of quantification and concentration ranges of the proposed method were 0.0796 ?g?mL?1 (signal/noise=3), 0.5560 ?g?mL?1 and 0.1 to 10.0 ?g?mL?1, respectively. The electrochemical sensor was successfully applied for the detection of ametridione in tap, agricultural run-off and river water samples showing >98% mean recoveries.   &nbsp

Quark Matter in Neutron Stars: An apercu

The existence of deconfined quark matter in the superdense interior of neutron stars is a key question that has drawn considerable attention over the past few decades. Quark matter can comprise an arbitrary fraction of the star, from 0 for a pure neutron star to 1 for a pure quark star, depending on the equation of state of matter at high density. From an astrophysical viewpoint, these two extreme cases are generally expected to manifest different observational signatures. An intermediate fraction implies a hybrid star, where the interior consists of mixed or homogeneous phases of quark and nuclear matter, depending on surface and Coulomb energy costs, as well as other finite size and screening effects. In this brief review article, we discuss what we can deduce about quark matter in neutron stars in light of recent exciting developments in neutron star observations. We state the theoretical ideas underlying the equation of state of dense quark matter, including color superconducting quark matter. We also highlight recent advances stemming from re-examination of an old paradigm for the surface structure of quark stars and discuss possible evolutionary scenarios from neutron stars to quark stars, with emphasis on astrophysical observations.Comment: 15 pages, 1 figure. Invited review for Modern Physics Letters

DESIGN AND DEVELOPMENT OF ORAL SUSTAINED RELEASE MATRIX TABLETS OF DIDANOSINE

Objectives: In present study, an attempt was made to design sustained-release tablets containing Didanosine using natural gums like Xanthan gum, Guar gum and Karaya gum. Methods: The sustained-release tablets containing Didanosine prepared by using natural gums by wet granulation method. Influence of natural polymer on Didanosine was studied. The prepared tablets were selected for DSC and FTIR studies.Results and Discussions: The tablets were selected for DSC and FTIR studies did not show any chemical interaction between drug and polymer. The prepared formulations were evaluated for Hardness, Thickness, Friability, Weight variation, drug content estimation, Swelling index, in-vitro drug release are within the acceptable standard. In-vitro release profile was check for 8 hrs to evaluate the SR matrix tablet of Didanosine. The optimized tablets were carried out according to ICH guidelines at 40 ± 2º C/ 75 ± 5percent RH for three months. All the prepared tablets were stable at room temperature. The values of pre-compression parameters of prepared granules were evaluated the results were within prescribed limits and indicated good free flowing property. The prepared tablets were subjected to all the quality control tests they were within the official pharmacopoeial limits. Friability is less than 1percent, indicated that tablets had a good mechanical resistance. Weight variation test revealed that the tablets were within the range of pharmacopoeial limit. Thickness, hardness and drug content were within the range of pharmacopoeial limit. The evaluation parameters were within acceptable range for all the formulations. The in-vitro release of Didanosine was conducted for 8 hrs. The optimized formulations WGX3, WGG5 and WGK9 sustained the release up to 8hr. Hence Didanosine along with Xanthan gum, Guar gum and Karaya Gum could be used to prepared sustained released matrix tablets. The in-vitro release obeyed zero order kinetics with mechanism of release was erosion followed by non-fickian diffusion.Conclusion: Among all the formulations WGK9 is the best shows excellent release around 99percent after 8 hrs. The prepared matrix tablets of Didanosine were stable. So, it may be concluded that sustained release matrix tablets would improve the patient compliance and bioavailability may be improved. Keywords:  Didanosine, Xanthan gum, Guar gum and Karaya gum

Identification and validation of an allele specific marker associated with pungency in Capsicum spp.

Pungency or heat in Capsicum spp. is due to the accumulation of unique secondary compounds known as capsaicinoids in their placental tissues. Detecting presence or absence of pungency at the nursery stage is a challenging task in CMS based hybrid pepper breeding programs. In this study a DNA sequence possibly related to pungency trait with high similarity to Pun1 or At3 gene was investigated. Nucleotide alignment of the obtained sequences and corresponding fragment from the data base has revealed a 16bp deletion in C.annuum ‘Maor’. A multiplex agarose based co-dominant marker was designed to detect the identified polymorphism and named it as Cen1. This Cen1 marker is validated in a panel of 27 pepper genotypes belonging to C.annuum, C.chinensis, C.frutescens and C.baccatum for its wide utility. All these Capsicum accessions were correctly discriminated with phenotype. In addition, the ability of Cen1 marker to discriminate homozygous and heterozygous plants was demonstrated in F1 hybrids crossed from a non pungent ‘Maor’ and a pungent ‘Habanero’. The Cen1 marker was also associated with phenotypic character in the tested genotypes. Moreover the linkage association of Cen1 with At3 or Pun1 gene has also been discussed. Therefore the developed functional marker in this study will be highly useful in marker assisted selection (MAS) programmes, germplasam characterization and seed purity testing of chill

Enhancing technology generation and transfer through coalition approach: a case of sorghum poultry coalition, Andhra Pradesh, India

This paper describes an innovative institutional arrangement for the generation and dissemination of new knowledge and the formation of sustainable economic interlinkages through coalition among researchers, farmers, farmers associations, poultry feed manufacturers and the poultry producers. The goal of this arrangement is to enhance on-farm productivity of sorghum and increase poor sorghum farmers’ income by establishing market linkages between poor sorghum growers and poultry feed manufacturers. Under this project, farmers were supplied with seed of improved sorghum cultivars and were trained in bulking and storage of grain; feed manufacturers developed poultry feed rations with sorghum replacing maize at varying proportions; and scientists conducted poultry trials with sorghum-based feed rations with appreciable results. Finally, the project linked sorghum-growing farmer groups with end-users i.e. feed manufacturers, thus assuring a market for the poor sorghum growers. The coalition system was successful as it provided an opportunity to members to contribute knowledge in their respective fields, work towards a common goal with clearly defined roles and responsibilities, articulating problems, finding solutions, exploiting the synergies of working in groups and sharing the lessons learnt. Success of the coalition approach was facilitated by frequent review meetings with specific agenda, consensus approach to resolve issues, openness in interactions with various partners and use of electronic media, which helped to enhance the effectiveness of each partner’s role