Improvement of Flux Regulation with Adaptive PI Controller and DTHB based Direct Torque Control of Induction Machine

This paper presents an adaptive PI based two control strategies of Dynamic Hysteresis Torque Band (DHTB) for improving flux regulation at low speed and zero speed in lookup table based Direct Torque Control (DTC) of an Induction Machine (IM). This is achieved by varying the band value of torque dynamically but it is limited with flux error range. With the conventional HTB based DTC, at low and zero speed, the regulation of flux will not be good. To overcome this drawback, a small alteration in the structure is done, i.e., DTHB, thus retaining the simplicity of DTC algorithm. The performance is verified by varying the speed at low values. At low speeds of IM, the flux regulation and the speed is improved with adaptive PI controller based DHTB-II compared to DTC with DHTB-I and DHTB-II.

Placental pathology and its correlation with immediate feto neonatal outcome

Background: Placenta plays a major role in growth and development of the fetus as it helps in both exchange of nutrients and removal of waste. Even though it yields a valuable information of prognostic significance for the newborn, majority of the time it will be discarded after the gross examination. Hence the present study was conducted to determine the placental pathology and its correlation with fetal outcome.Methods: The present study was carried out in Davangere for a period of 2 years. The placenta of 100 parturients, more than 28 weeks of gestation were included for the present study. The data was collected after detailed review of the obstetric case records. Placentas were examined soon after delivery. After the gross examination was complete, the placentas were put in a labelled plastic container. The placentas were re-examined macroscopically again by the pathologist. Cut-section examination was done. Then, at least 4 appropriate blocks were taken for each placenta. They were stained with hematoxylin-eosin stain and examined under the microscope. The histopathological examination was conducted as per proforma.Results: One hundred placentae belonging to one hundred babies were studied among which 80% of the maternal cases had anaemia, 68% were term infant, 37% had IUGR. Eccentric insertion of the cord was observed to be the commonest (51). Marginally inserted membranes were seen most frequently (97).Conclusions: In the present study we conclude that placental reserve is large and small alteration do not affect the pregnancy outcome. The placental changes are not specific to a particular condition affecting the pregnancy.

IMPLEMENTING CANONICAL SEESAW MECHANISM IN THE EXACT SOLUTION OF A 3-3-1 GAUGE MODEL WITHOUT EXOTIC ELECTRIC CHARGES

We prove that, even at a low TeV scale, the canonical seesaw mechanism can be naturally implemented in the exact solution of a particular 3-3-1 gauge model, since a very small alteration ε in the parameter matrix of the Higgs sector is taken into account. Therefore, this new parameter can act as an appropriate mass source for neutrinos, while, due to the main parameter a, all the previously achieved results in the exact solution of the model are recovered. Moreover, this mathematical artifice does separate the boson mass spectrum from the neutrino mass issue, hence giving more flexibility in tuning the model. Possible phenomenological results and their implications — such as dark matter plausible candidates that can occur — are also briefly discussed.

Fault Tolerant Boolean Satisfiability

A delta-model is a satisfying assignment of a Boolean formula for which any small alteration, such as a single bit flip, can be repaired by flips to some small number of other bits, yielding a new satisfying assignment. These satisfying assignments represent robust solutions to optimization problems (e.g., scheduling) where it is possible to recover from unforeseen events (e.g., a resource becoming unavailable). The concept of delta-models was introduced by Ginsberg, Parkes and Roy (AAAI 1998) , where it was proved that finding delta-models for general Boolean formulas is NP-complete. In this paper, we extend that result by studying the complexity of finding delta-models for classes of Boolean formulas which are known to have polynomial time satisfiability solvers. In particular, we examine 2-SAT, Horn-SAT, Affine-SAT, dual-Horn-SAT, 0-valid and 1-valid SAT. We see a wide variation in the complexity of finding delta-models, e.g., while 2-SAT and Affine-SAT have polynomial time tests for delta-models, testing whether a Horn-SAT formula has one is NP-complete.

Laser driven pyrolysis of n-alkanes

CW CO2 laser photosensitized (SF6) homogeneous pyrolysis of n-alkanes (C5-C7) affords almost twice higher yield of important ethylene compared to conventional pyrolysis in tubular reactors. No production of heavy pyrolytic oils, resins or coke and very small alteration of the pyrolytic distribution with the conversion are other advantages of the laser process that can be ascribed to the absence of in conventional reactors important surface reactions.

Difficulties Associated with Predicting Depth of Freeze or Thaw

Calculations using the Neumann solution (as modified by Aldrich) and thermal properties of soils (obtained by Kersten) show that the frost penetration depth for the same freezing index for essentially all soils with any moisture content and for dry sand and rock varies by a factor of about 2 to 1. The extremes calculated in this way bracket the experimentally determined design curve of the US Army Corps of Engineers and give it theoretical support. The theoretical calculations and additional experimental data are used as a basis for a small alteration in the slope of the design curve. This modified design curve is recommended for field use because of (1) inherent imperfections in existing theory and (2) practical limitations to precise specification of field conditions.

Serologische Untersuchungen an Mutanten des Tabakmosaikvirus

A series of sequential mutants from TMV strain vulgare has been serologically investigated using the absorption technique. The ultimate members of this series were selected as producing symptoms similar to TMV strains of the dahlemense group. Each mutation was accompanied by a small alteration of the antigenic properties, which was retained in the subsequent mutants. The end strain of the series therefore possessed the minute but clearly demonstrable antigenic changes of the preceeding mutants, and in exchange had lost some antigenic components of the original strain. However, the group specificity remained unaltered. Although the symptomatic properties approach those of the dahlemense group, no parallel approach of the serological characteristics was observed.

The absorption of light in caesium vapour in the presence of foreign gases

The absorption of caesium vapour on the short wave-length side of the series-limit, alone, and in the presence of helium, has been described in earlier papers. It was shown that helium, at a pressure of a few centi metres of mercury, greatly reduced the absorption at all wave-lengths and also produced significant changes in the shape of the absorption curve. No theoretical explanation of these results has been given. At this stage of the investigation it appeared more desirable to obtain measurements of moderate accuracy on a number of gases, rather than to attempt very detailed and accurate measurements on one other gas. The present paper contains results on the absorption of caesium in the presence of the following gases:—neon, argon, krypton, xenon, nitrogen, hydrogen, deuterium, and benzene. All these gases give effects qualitatively similar to those produced by helium. It is still not possible to give a detailed theory of the results, but some empirical generalizations emerge from the extensive data now available. Experimental The methods used for the control of temperature were similar to those previously described. The photometric technique was the same except for one small alteration. In the experiments on the absorption of caesium in the presence of helium, the absorption was measured by comparison with certain grids. The reduction of light produced by these grids had previously been measured and they were used in the experiments on the absorption of caesium in vacuum. Some of the present experiments were carried out in this way, but in the later experiments the absorption of caesium in the presence of the foreign gas was compared more directly with the absorption of caesium in vacuum, by recording both kinds of absorption spectra on the same plate. Suitable calibration spectra were also included. This direct comparison eliminated the possibility of systematic errors due to imperfect temperature control, etc. It also reduced the effect of random errors.

The Spondeion Scale

Our information about the early stages of Greek music is so slight that these references of Aristides Quintilianus (p. 28, Meibom) to an the Pseudo-Plutarch to a scale employed by the legendary figure Olympus take on an immense value for us. The dialogue itself is an unskilful patchwork, but the author's sources are often good. These particular passages are almost certainly both derived with small alteration from Aristoxenus, in whose time the traditional music ascribed to Olympus was still in use. For the elucidation of the scale's history and structure we have three1 pieces of evidence to help us. There is the first passage mentioned above, which deals with the discovery of the enharmonic genus by Olympus, which is connected, at first sight obscurely, with the Spondeion scale; and the second passage, which discusses the scalar limitations of theσφoνδειξων τρόφoς with especial reference to an elementary polyphony. There are also the ancient scales quoted by Aristides Quintilianus (ed. Meibom, p. 21).