Parametric analysis of Asymmetric Spur Gear Tooth

Abstract Gear is a machine element used to transmit motion and power between rotating shafts by means of progressive engagement of projections called teeth. Gears are classified according to the relative position of the axes of the shaft, type of gearing, peripheral velocity of the gears and position of teeth on gear surface. Presently gears are suffered by backlash the amount by which the width of a tooth space exceeds the thickness of the engaging tooth on the pitch circles, undercut a condition in generated gear teeth when any part of the fillet curve lies inside of a line drawn tangent to the working profile at its lowest point and interference is an important aspect of kinematics of gearing. When the gear tooth tries to dig below the base circle of mating gear then the gear tooth action shall be non conjugate and violate the fundamental law of gearing this non conjugate action is called the interference . These defects can be eliminated by increasing the pressure angle, by increasing the addendum of mating gear and another way of increasing the load capacity of transmissions is to modify the involute geometry. This has been a standard practice in sophisticated gear design for many years. The nomenclature describing these types of gear modifications can be quite confusing with reference to addendum modification or profile shift. An additional alteration that is very rarely used is to make the gears asymmetric with different pressure angles for each side of the tooth. An asymmetric spur gear drive means that larger and smaller pressure angles are applied for the driving and coast sides. The two profiles of a gear tooth are functionally different for most gear drives. The workload on one side of profile is significantly higher than the other Gears. The main objective of this paper is to generate asymmetric spur gear tooth geometry for different pressure angles on drive and coast side using computer programme. Developed programme is used to create a finite element model of gear tooth to study the effect of bending stress at the critical section for different pressure angles, different number of teeth and module. To study the effect of above asymmetric spur tooth parameters Finite Element Analysis software ANSYS was used

A UNIQUE MODULATOR FOR BOOST REGULATOR TO REDUCE THE VOLTAGE STRESS

The APS control can be used to lessen the current force on switches see how to avoid load as the traditional interleaving control can be used to help keep better performance in heavy load. This paper looks into a manuscript pulse width modulation (PWM) plan for 2-phase interleaved boost ripper tools with current multiplier for fuel cell power system by mixing alternating phase shift (APS) control and traditional interleaving PWM control. To be able to reduce output fuel cell stack output current ripple or even the electricity/electricity ripper tools input current ripple, whether passive filter or active filter may be used, however, this will raise the complexity from the system. The boundary condition for swapping between APS and traditional interleaving PWM control comes. In line with the aforementioned analysis, a complete power range control mixing APS and traditional interleaving control is suggested. Loss breakdown analysis can also be given look around the efficiency from the ripper tools. Finally, it's verified by experimental results. The whole process of a switching cycle from the ripper tools could be split into six stages at boundary condition that the current force on switch is going to be bigger than 1 / 2 of the output current with traditional interleaving control

A generalized Pancharatnam geometric phase formula for three level systems

We describe a generalisation of the well known Pancharatnam geometric phase formula for two level systems, to evolution of a three-level system along a geodesic triangle in state space. This is achieved by using a recently developed generalisation of the Poincare sphere method, to represent pure states of a three-level quantum system in a convenient geometrical manner. The construction depends on the properties of the group SU(3)\/ and its generators in the defining representation, and uses geometrical objects and operations in an eight dimensional real Euclidean space. Implications for an n-level system are also discussed.Comment: 12 pages, Revtex, one figure, epsf used for figure insertio

Topological Phases near a Triple Degeneracy

We study the pattern of three state topological phases that appear in systems with real Hamiltonians and wave functions. We give a simple geometric construction for representing these phases. We then apply our results to understand previous work on three state phases. We point out that the ``mirror symmetry'' of wave functions noticed in microwave experiments can be simply understood in our framework.Comment: 4 pages, 1 figure, to appear in Phys. Rev. Let

Adherence to anti-retroviral therapy among HIV patients in Bangalore, India

<p>Abstract</p> <p>Introduction</p> <p><it>Human Immunodeficiency Virus </it>(HIV) has an estimated prevalence of 0.9% in India (5.2 million). Anti-retroviral drugs (ARV) are the treatments of choice and non-adherence is an important factor in treatment failure and development of resistance, as well as being a powerful predictor of survival. This study assesses adherence to ARV in HIV positive patients in Bangalore, India, a country where only 10% of those who need therapy are receiving it.</p> <p>Methods</p> <p>A cross-sectional anonymous questionnaire survey of 60 HIV antibody positive patients was carried out with patients attending HIV outpatient services at two centres: The Chest and Maternity Centre, Rajajinagar, and Wockhardt Hospital and Heart Institute, Bangalore. Consent was obtained. Translation was done by a translator and doctors where required. Data was analysed using SPSS statistical analysis.</p> <p>Results</p> <p>A response rate of 88% (53/60) was achieved. The mean patient age was 39.98 years, with 50% aged 30–40, and 73.6% of participants being male. Mean family size was 4.8 (1–13). 21% lived less than 50 kms and 21% greater than 400 kms from clinic.</p> <p>60% reported they were fully adherent. Adherence was statistically significantly linked to regular follow-up attendance (70.5%, p = 0.002). No other results were statistically significant but trends were found. "100% adherence" trends were seen in older patients, male gender, those from larger families, those who had a previous AIDS defining illness, those taking fewer tablets, and without food restrictions. Commonest side-effects causing non-adherence were metabolic reasons (66%) and GI symptoms (50%). No trends were seen for education level, family income, distance travelled to clinic, time since diagnosis, or time on ART.</p> <p>Conclusion</p> <p>Regular attendance for follow up was statistically significant for 100% lifetime adherence. Positive trends were seen in those in larger families, older, those who had AIDS defining illness, simple regimes, and without side-effects. Education, income, distance travelled and length of time diagnosed or treated had no effect on adherence.</p

SU(3) representation for the polarisation of light

A new mathematical representation for discussing the state of polarisation of an arbitrary beam of partially polarised light is described which makes use of the generators of the group SU(3). This representation is sufficiently general to describe not only physical photons which are transverse but also virtual photons. The correspondence between our representation and the conventional Stokes parameter representation is established and this leads to an equivalent geometrical description of partially polarised light in terms of diametrically opposite points on a Poincarè sphere with radius equal to the degree of polarisation. The connection with the spherical tensor representation is also discussed and this leads to a simple geometrical interpretation of the bounds on the parameters characterizing an arbitrary beam of partially polarised light

Performance assessment of fly-ash aggregates in concrete

In recent year’s construction process is vigorous and never ending process due to the exponential growth of population in the countries like India. It’s necessary to search for the alternative building materials and there are so many research work has been carried out to find the alternative material. Concrete is one the commonly used construction material. In previous research works carried out to find the fly-ash aggregates as alternative aggregates for coarser aggregate and found some draw backs in shape factor, impact, and compression and abrasion tests. In this study an effort is made to overcome those drawbacks. A work has been carried out to examine the behaviour of aggregates manufactured with the combination of cement, Fly ash and stone dust with various proportions and the aggregates are prepared by the process of pelletisation and finger moulding. The properties of the manufactured aggregates are compared with the conventional aggregates and the performance of fly-ash aggregates in concrete is assessed by replacing the conventional coarse aggregates by manufactured aggregates in concrete. These aggregates performed better and proven to be an alternative coarse aggregate in concrete in future

Flight Envelope Expansion via Active Control Solutions for a Generic Tailless Aircraft

Aircraft dynamics at high angles of attack due to loss of stability and control essentially limits its manoeuvrability. Modern control systems implement flight envelope protection at the cost of maneuverability to improve safety in these conditions. Flight envelope boundaries, which are set taking into account deterioration of stability and controllability due to separated flow, can be expanded by appropriate design of control laws. However, such a design requires extensive analysis of the maneuver envelope of the airframe and its utilization by the flight envelope protection laws. The reliability of this analysis depends on the adequate aerodynamic modeling which captures nonlinear unsteady variation of aerodynamic loads in these flight regimes. Two novel models for unsteady aerodynamics at low and high subsonic Mach numbers are described. These models and prototyping control laws are used for closed loop computational analysis. The computational methodology of clearing flight control laws for flight envelope expansion of a Generic Tailless Aircraft (GTA) is addresse