1,014 research outputs found
Indigenous development of ultra high vacuum (UHV) magnetron sputtering system for the preparation of Permalloy magnetic thin films
We have designed and developed an indigenous ultra high vacuum (UHV) sputtering system which can deposit magnetic thin films with high purity and good uniformity. The equipment consists of state-of the-art technologies and sophistication. With this system it is possible to deposit coatings of various materials on a sample size of 3”3” 3”. The Ni81Fe19 ferromagnetic thin films, with Tantalum (Ta) as a buffer and cap layers have been deposited on silicon substrates using this ultra high vacuum (UHV) sputtering system. The magneto transport measurement study indicated a significant variation in the AMR values of the films for varying thicknesses of tantalum and NiFe layers
Internetworking Transmission in Cells Loss Designing MPLS and ATM Networks
ATM is the new generation of computer and communication networks that are being deployed throughout the telecommunication industry as well as in campus black bones. OPNET is a CAD tools which is specialized in communication protocols and networks. We examine its performance and its effect on the traffic pattern in an ATM network. In this paper we also report the studies of simulation efficiency and network performance of simulated network using firewall
QOS Reliability and Improvement for Congestion Probability Routing in ATM Networks
The other primitives for switch management and control are borrowed heavily from the specified protocol. They include priority for switch configuration port and switch management VP management and permanent measurement. The protocol was implemented and integrated with the OPNET platform. Without going into specifies of the protocol we describe its design principles and show how it has affected in the protocol. Traditional connection switches include an embedded processor that implements both the switch control and network signaling. The objective of CAC is to keep the network load moderate to achieve a performance objective associated with QOS. Cell loss ratio a key QOS parameter in ATM networks is essential for proper network resources dimensioning, congestion control , bandwidth allocation and routing. Keywords: Quality of Service, Servicing Monitoring
Traffic Control and Distributed Optimization Routing Problems in ATM Networks
Aggressive research as gigabit network has led to dramatic improvements in network transmission speeds. One result of these improvements has been to put pressure on router technology to keep peace. This paper describes a router nearly completed. This is more than fast enough to keep up with the latest transmission technology. This router has a back place speed of 50 gigabit and can forward tens of millions packet.Scheduling algorithm can be implemented on CVAR applications but in this research scheduling is implemented on CBR applications and the performance on WLAN network is enclosed by delivering different traffic load. QOS parameters [5] will be considered as the performance metrics on this study. The comparative study of various algorithms can show the best scheduling algorithm in WLAN with CBR applications.ATM was the focus of action research and significant investment in the early to mid 1990’s. This paper discuss several visions for ATM prevalent at the time and analyses how ATM evolved during this period this paper also consider the amplifications of this history for current connection oriented technologies such as optical transport network and MPLS
Evaluation of MPLS Framework Congestion Control for Planning and Optimization in ATM Networks
Recent Advances in MPLS have led to development of real-time applications. Many routing protocols have been specifically designed for these applications where real-time guarantee is an essential design issue. Real-time MPLS is an existing area of research. The common objective is trying to provide timeless guarantee for resource constrained MPLS. MPLS is emerging as a flexible technology that can transport voice,. IPV4 , IPV6 layer 2 services and even PDH and SDH/SONET circuit over a single packet infrastructure in a new attempt to solve the old problem of new network convergence. MPLS traffic emerging QOS support and fast restoration capabilities can be used to provide each service with strict service level arguments in a cost efficient way several standardization and industry organization are contributing to this goal. Keywords: Congestion Control, MPLS
Internet Traffic Control System and Mobile Broadband Communication System in ATM Networks
MPLS is an advanced forwarding scheme which allows the network to achieve the benefits provided by traffic engineering techniques. The establishment of an end to end LSP between two IP/MPLS networks inter connected through an ATM backbone is still an open issue. This focuses in an MPLS ATM environment and address problem of provisioning a fast LSP establishment with certain QOS between 2 MPLS sub networks inter connected through an ATM backbone. The PNNI is used in ATM backbone as a routing and signaling protocol. In order to achieve the paper objectives and new PNNI elements are defined and evaluated. Voice has been the primary application in wireless network to date. However packet based application and higher bandwidth requirements to sustain these applications are ever emerging. As in wire line packet based networks while IP routing is well understood IP network by itself is still not achieved and its depart on the backbone that can offer QOS guarantee. MPLS is a newer technology that offer service information layer 2 switching and connection oriented that allows traffic engineering control traffic flows in the network. The purpose of it to show how MPLS QOS Architecture can be employed to provide traffic engineering in broadband wireless network. Keywords: Multiservice traffic, Mobile Broadband system
Cell Multiplexing and Adaptive Scheduling for Wide Area ATM Networks
The ATM UBR, GFR over ABR service categories have been designed for data. However several studies have responded poor TCP performance over satellite ATM resources. We first discuss the various design options available for TCP end systems, IP-ATM switches for long latency connections. We discuss the buffer management policies generated and rate services and the virtual stores destination options in ATM. We present comparison of ATM service categories for TCP transport over satellite links. Keywords: Video Teleconferencing, Adaptive Schedulin
Gunn Effect in Silicon Nanowires: Charge Transport under High Electric Field
Gunn (or Gunn-Hilsum) Effect and its associated negative differential
resistivity (NDR) emanates from transfer of electrons between two different
energy bands in a semiconductor. If applying a voltage (electric field)
transfers electrons from an energy sub band of a low effective mass to a second
one with higher effective mass, then the current drops. This manifests itself
as a negative slope or NDR in the I-V characteristics of the device which is in
essence due to the reduction of electron mobility. Recalling that mobility is
inversely proportional to electron effective mass or curvature of the energy
sub band. This effect was observed in semiconductors like GaAs which has direct
bandgap of very low effective mass and its second indirect sub band is about
300 meV above the former. More importantly a self-repeating oscillation of
spatially accumulated charge carriers along the transport direction occurs
which is the artifact of NDR, a process which is called Gunn oscillation and
was observed by J. B. Gunn. In sharp contrast to GaAs, bulk silicon has a very
high energy spacing (~1 eV) which renders the initiation of transfer-induced
NDR unobservable. Using Density Functional Theory (DFT), semi-empirical 10
orbital () Tight Binding (TB) method and Ensemble Monte Carlo
(EMC) simulations we show for the first time that (a) Gunn Effect can be
induced in narrow silicon nanowires with diameters of 3.1 nm under 3 % tensile
strain and an electric field of 5000 V/cm, (b) the onset of NDR in I-V
characteristics is reversibly adjustable by strain and (c) strain can modulate
the value of resistivity by a factor 2.3 for SiNWs of normal I-V
characteristics i.e. those without NDR. These observations are promising for
applications of SiNWs in electromechanical sensors and adjustable microwave
oscillators.Comment: 18 pages, 6 figures, 63 reference
A study on functional and radiological outcome of unstable intertrochanteric fractures managed by modular extension of dynamic hip screw
INTRODUCTION:
Intertrochanteric fractures continues to be a challenge for all orthopaedic surgeons.
A variety of implants of internal fixation have been employed to achieve this goal
with variable success.The Diversity of fixation devices available for the treatment
of trochanteric fractures illustrates the difficulties encountered in the actual
treatment,and the discussion about ideal implant still continues.In Recent years the
use of DHS in Unstable trochanteric fractures has been associated with significant
medial displacement of the shaft resulting from excessive sliding of screw within
the barrel and a higher incidence of srew cut out.Morever 12% of unstable
intertrochanteric fractures shows radiologically identifiable rotation of proximal
fragment when fixed with DHS, as DHS provides single point fixation over which
the proximal fragment rotates on hip movements.This leads to more malunions and
nonunions. Hence stabilization of lateral wall in unstable fractures by addition of
TSP to DHS prevents the excessive collapse and varus malpositioning.
BACK GROUND:
To emphasis the importance of the modular trochanter stabilizing plate (TSP) in
addition to the dynamic hip screw (DHS) prevents excessive telescoping/varus
malposition and limb shortening in all unstable trochanteric fractures with lateral
communitions.
MATERIAL AND METHOD:
In our study conducted in Government Kilpauk Medical College and Hospital
Chennai, 20 consecutive patients of unstable intertrochanteric fractures with lateral
wall communition were treated with trochanteric stabilization plate between
August 2013 and August2015. The fractures were classified according to AO/OTA
classification and fractures of AO Type 31A2.1 to 31A2.3 were included in our
study.All cases were followed up for a minimum of 9 months and were assessed
for clinical, radiological and functional outcome. The results were analysed
RESULTS:
The postoperative radiological outcome was assessed by taking serial X rays of
affected hip in anteroposterior and lateral view. All patients achieved union
radiological and clinical union. 6 patients underwent radiological union by 16
weeks, 4 patients underwent by 18 weeks, 5 patients underwent union by 20 weeks
and 3 patients underwent union by 22 weeks.Two patients had varus malunion,
Average limb length discrepancy was 1.4 cm with 7 patients having <1cm
shortening, 11 had shortening of 1.5 to 2 cm and 2 had shortening of more than 2
cm (1 patient had shortening of 2.5 cm and another had shortening of 2.9
cm).Average time for radiological union was 23.5 weeks. The postoperative
functional outcome was assessed by Harris Hip Score at 20 weeks. Average Harris
hip score was 83.2. We had 3 excellent results, 14 good results and 3 fair results.
CONCLUSION:Trochanteric stabilization plate with sliding hip screw is a
biomechanically stable construct allowing reconstruction of lateral wall to maintain
adequate lever arm and abductor strength (power arm) in unstable intertrochanteric
fractures with lateral wall communition. Additional anti rotation screw provides
enhanced rotational stability to the proximal fragment. Lateral wall buttress effect
reduces the chance of varus collapse and screw cutout. The operative technique
being similar to sliding hip screw.Overall in patients with unstable
intertrochanteric fractures with lateral wall communition, trochanteric stabilization
plate can give a superior functional and radiological outcome
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