Computational method to predict thermodynamic, transport, and flow properties for the modified Langley 8-foot high-temperature tunnel

The Langley 8 foot high temperature tunnel (8 ft HTT) is used to test components of hypersonic vehicles for aerothermal loads definition and structural component verification. The test medium of the 8 ft HTT is obtained by burning a mixture of methane and air under high pressure; the combustion products are expanded through an axisymmetric conical contoured nozzle to simulate atmospheric flight at Mach 7. This facility was modified to raise the oxygen content of the test medium to match that of air and to include Mach 4 and Mach 5 capabilities. These modifications will facilitate the testing of hypersonic air breathing propulsion systems for a wide range of flight conditions. A computational method to predict the thermodynamic, transport, and flow properties of the equilibrium chemically reacting oxygen enriched methane-air combustion products was implemented in a computer code. This code calculates the fuel, air, and oxygen mass flow rates and test section flow properties for Mach 7, 5, and 4 nozzle configurations for given combustor and mixer conditions. Salient features of the 8 ft HTT are described, and some of the predicted tunnel operational characteristics are presented in the carpet plots to assist users in preparing test plans

Assessment of the functional outcome of Arthroscopic Reconstruction of Anterior Cruciate Ligament using Hamstring Tendon Autograft

INTRODUCTION: Knee injuries are increasing and becoming more common due to the exponential rise in road traffic accidents and sports related activities by common people. In current scenario, knee injuries take the Orthopaedician to a plethora of diagnostic and management challenges which is not resolved even by modern understanding and technical improvements in science. Anterior cruciate ligament is one amongst the most common injured structure around knee. Being one of the prime stabilizers of the knee, the major role of Anterior cruciate ligament is to resist anterior translation of the tibia on the femur. ACL also contributes to stabilize the knee against varus and valgus stress, excessive hyperextension and proprioception. As ACL doesn’t heal with repair, reconstruction is the only possibility. Anterior cruciate ligament reconstruction is done to improve stability of the knee joint, to prevent later meniscal tear and to delay the onset of early osteoarthritis. Graft tissue selection, graft placement, methods of graft fixation, variations in the rehabilitation protocol, post reconstruction functional bracing, and criteria for return to routine activities remains controversial. As the open ACL reconstruction has prolonged rehabilitation and more complications, arthroscopic assisted ACL reconstruction is a boon for such injuries where precision and rehabilitation is quick. Since early return to daily routine with full range of movements and minimal donor site morbidities is feasible following arthroscopic reconstruction of ACL, it is considered more superior to the extraarticular and intraarticular reconstruction by open arthrotomy. OBJECTIVE: The aim of this study is to assess the functional outcome of Arthroscopic Reconstruction of Anterior Cruciate Ligament using hamstring tendon autograft. MATERIALS AND METHODS: This is a study done on 20 patients presenting with knee instability, who were clinically examined and confirmed by MRI for ACL insufficiency and treated with arthroscopic reconstruction of ACL with hamstring tendon autograft between July 2015 and July 2016 at Government Stanley Hospital, Chennai. Patients were followed up at 4 weeks, 3 months, 6 months and once in every 6 months thereafter. All patients were evaluated and graded with International Knee Documentation Committee (IKDC) examination form. RESULTS: ACL injury more commonly occurs in males in the younger age group (20-30 years). The most common mode of injury is Road traffic accident followed by sports. Out of 20 patients, 15 patients had a normal knee (IKDC Grade A), 4 patients had a nearly normal knee (IKDC Grade B) and one patient ended up with abnormal knee (IKDC Grade C). Two patients with Anterior cruciate ligament injury presenting more than three years since initial trauma ended up with osteoarthritis changes in the knee. CONCLUSION: The arthroscopic technique of hamstring tendon autograft for ACL reconstruction using the endobutton for femoral fixation and interference screw for tibial fixation has low morbidity and excellent functional results. Proper surgical technique, adequate graft fixation and good post-operative rehabilitation warrants excellent functional results with Arthroscopic ACL reconstruction using hamstring tendon autograft

Drainage Morphometric Analysis of the Nagavathi Watershed of Dharmapuri District, Tamil Nadu, India Using SRTM Data and GIS

GIS and Remote sensing have proved to be a resourceful tool in the explanation of drainage pattern for water resources management and its planning. The identification of morphometric characteristics based on a Geographic Information System (GIS) was carried out in the Nagavathi watershed, Dharmapuri District. The quantitative drainage morphometric parameters was carried out for the Nagavathi watershed by estimating their (a) Linear aspects like Stream number, Stream order, Stream length, Mean stream length, Stream length ratio, Bifurcation ratio, (b) Aerial aspects like Drainage density, Stream frequency, Texture Ratio, Elongation ratio, Form factor, Circularity index, Length of overflow, Constant of Channel maintenance, Drainage texture, Compactness coefficient and (c) Relief aspects like Basin relief, Relief ratio, Ruggedness number, Gradient ratio, Melton ruggedness ratio, Slope,  relative relief, Shape Factor and Leminscate.  The drainage area of Nagavithi watershed is 482 sq. Km. the main drainage patterns is dendritic to sub-dendritic drainage. The Nagavathi watershed was classified as a fifth order drainage watershed, whereas micro watershed was classified as an eight in the watershed. Stream order of the watershed was predominantly controlled by structural and lithological controls of various drainage patterns and their stream orientations were identified to evaluate the direction and controlling factors in drainage network. The drainage density in the area has been found to be low which indicates that the area possesses highly permeable soils and low relief. The bifurcation ratio varies from 0.8 to 43.1. The elongation ratio of  Microwatersheds  varies  from  0.13  to  0.43, indicates  Microwatersheds  fall  under elongated  pattern. This study would help the local people to utilize the resources for planning rainwater harvesting and watershed management

Intrusion Detection Systems for Community Wireless Mesh Networks

Wireless mesh networks are being increasingly used to provide affordable network connectivity to communities where wired deployment strategies are either not possible or are prohibitively expensive. Unfortunately, computer networks (including mesh networks) are frequently being exploited by increasingly profit-driven and insidious attackers, which can affect their utility for legitimate use. In response to this, a number of countermeasures have been developed, including intrusion detection systems that aim to detect anomalous behaviour caused by attacks. We present a set of socio-technical challenges associated with developing an intrusion detection system for a community wireless mesh network. The attack space on a mesh network is particularly large; we motivate the need for and describe the challenges of adopting an asset-driven approach to managing this space. Finally, we present an initial design of a modular architecture for intrusion detection, highlighting how it addresses the identified challenges

Prescribing pattern and adverse drug effects monitoring of anti-rheumatoid drugs in rheumatoid arthritis patients in a tertiary care hospital

Background: Rheumatoid arthritis (RA) is a common disease that causes substantial morbidity in most patients and premature mortality in many. All the drugs used in the treatment of rheumatoid arthritis show significant toxicity and hence it is important to monitor the drugs for adverse drug reaction. This study will estimate the prescribing pattern and bring out the possible adverse drug reactions in patients with rheumatoid arthritis.Methods: This study included 200 patients with rheumatoid arthritis who fulfilled the study criteria were observed for three months. Their prescriptions were collected and analysed. The symptoms of adverse drug reaction were documented through questionnaire. The causality assessment was done by WHO-UMC assessment scale and severity by using modified Hartwig-Seigel severity assessment scale.Results: This study showed most of the patients were female (86%). Majority of them were in age group of 51-60 years. Average number of drugs per prescription was 10.57. Out of 200 patients, 2% were on single DMARD and 50.5% were on two DMARDs. 40% and 7.5% were taking three and four DMARDs respectively. A total of 450 adverse drug reactions were reported, out of which 68.4% due to steroid,12.5% due to DMARDs and 19.1 due to use of NSAIDs, DMARDs and glucocortisteroids. Chloroquine maculopathy occurred in 3 patients and elevated liver enzymes due to methotrexate in 3 patients, which necessitated DMARD withdrawal. Most patients had 1-3 ADRs. 6% of ADRs were severe and 54% belongs to probable category of causality assessment.Conclusions: Treatment of rheumatoid arthritis is mainly based on DMARDs, glucocorticosteroids and NSAIDs. So, occurrence of ADR is much common. Proper monitoring of therapy and timely modification of drugs and lifestyle can reduce the ADR occurrence

Gut microflora of some edible crabs from Porto Novo Coast

399-401Gut microflora of 5 commercially important crabs, viz. Charybdis cruciata (Herbst), Podophthalmus vigil (Fabricius) (marine), Scylla serrata (Forskal), Portumus pelagicus (Linnaeus), Podophthalmus sanguinolentus (Herbst) (estuarine), were studied. The midgut harboured highest aerobic and proteolytic bacteria. Luminescent bacterial flora were predominant in the hindgut and on the cuticular membrane of all the crabs examined. High numbers of heterotrophic bacteria were recorded in the midgut of Scylla serrata

Combustion Processes in Hybrid Rocket Engines

In recent years, there has been a resurgence of interest in the development of hybrid rocket engines for advanced launch vehicle applications. Hybrid propulsion systems use a solid fuel such as hydroxyl-terminated polybutadiene (HTPB) along with a gaseous/liquid oxidizer. The performance of hybrid combustors depends on the convective and radiative heat fluxes to the fuel surface, the rate of pyrolysis in the solid phase, and the turbulent combustion processes in the gaseous phases. These processes in combination specify the regression rates of the fuel surface and thereby the utilization efficiency of the fuel. In this paper, we employ computational fluid dynamics (CFD) techniques in order to gain a quantitative understanding of the physical trends in hybrid rocket combustors. The computational modeling is tailored to ongoing experiments at Penn State that employ a two dimensional slab burner configuration. The coordinated computational/experimental effort enables model validation while providing an understanding of the experimental observations. Computations to date have included the full length geometry with and with the aft nozzle section as well as shorter length domains for extensive parametric characterization. HTPB is sed as the fuel with 1,3 butadiene being taken as the gaseous product of the pyrolysis. Pure gaseous oxygen is taken as the oxidizer. The fuel regression rate is specified using an Arrhenius rate reaction, which the fuel surface temperature is given by an energy balance involving gas-phase convection and radiation as well as thermal conduction in the solid-phase. For the gas-phase combustion, a two step global reaction is used. The standard kappa - epsilon model is used for turbulence closure. Radiation is presently treated using a simple diffusion approximation which is valid for large optical path lengths, representative of radiation from soot particles. Computational results are obtained to determine the trends in the fuel burning or regression rates as a function of the head-end oxidizer mass flux, G=rho(e)U(e), and the chamber pressure. Furthermore, computation of the full slab burner configuration has also been obtained for various stages of the burn. Comparisons with available experimental data from small scale tests conducted by General Dynamics-Thiokol-Rocketdyne suggest reasonable agreement in the predicted regression rates. Future work will include: (1) a model for soot generation in the flame for more quantitative radiative transfer modelling, (2) a parametric study of combustion efficiency, and (3) transient calculations to help determine the possible mechanisms responsible for combustion instability in hybrid rocket motors

Validation of two-equation turbulence models for propulsion flowfields

The objective of the study is to assess the capability of two-equation turbulence models for simulating propulsion-related flowfields. The standard kappa-epsilon model with Chien's low Reynolds number formulation for near-wall effects is used as the baseline turbulence model. Several experimental test cases, representative of rocket combustor internal flowfields, are used to catalog the performance of the baseline model. Specific flowfields considered here include recirculating flow behind a backstep, mixing between coaxial jets and planar shear layers. Since turbulence solutions are notoriously dependent on grid and numerical methodology, the effects of grid refinement and artificial dissipation on numerical accuracy are studied. In the latter instance, computational results obtained with several central-differenced and upwind-based formulations are compared. Based on these results, improved turbulence modes such as enhanced kappa-epsilon models as well as other two-equation formulations (e.g., kappa-omega) are being studied. In addition, validation of swirling and reacting flowfields are also currently underway

Raman Spectra of the Mercaptans

It deals with the Raman Spectra of the Mercaptans@IAC