Feedback linearization of nonminimum phase systems and control of aeroelastic systems and undersea vehicles

The thesis presents the design of feedback control systems for a class of nonminimum phase single input-single output nonlinear systems. The linearized system is assumed to have one unstable zero. Since asymptotic or exact tracking of output trajectory cannot be accomplished, an approximate output is derived by neglecting the unstable zero. Based on the inversion of the new input-output map, a feedback linearizing control is derived; These results are applied to control an aeroelastic system and a small undersea vehicle. For pitch angle control and plunge motion regulation, an inverse control system is designed for the aeroelastic system. Simulation results are shown for the pitch controller and the design is found to be robust to variation in the parameters. Dive plane control of an undersea vehicle is accomplished using an inverse control law. To attenuate the effect of the surface waves, a servocompensator has been designed. Later, a controller is also designed using the sliding mode control technique, to make the system more robust

Analysis of the Association between Iron Deficiency Anemia and Simple Febrile Seizures

BACKGROUND: Febrile seizures occur as an age-dependent condition, with an incidence of 2 to 5 percent in children younger than five years of age. Iron deficiency anemia is common in developing countries. The association between the iron deficiency anemia and simple febrile seizures has been described in several studies with conflicting results. OBJECTIVES: 1. To analyse the association between iron deficiency anemia and simple febrile seizures. 2. To look for other significant risk factors for simple febrile seizures. METHODS: The study was a case control prospective study conducted on 200 children (6-60 months of age) admitted in the Paediatric ward of Government Theni Medical College Hospital, from July 2018 to June 2019. Cases were those presenting with simple febrile seizures. Controls were children with acute febrile illness without seizures. Inclusion criteria: Children aged 6 months to 60 months with febrile seizures admitted in Theni Medical College Hospital. Exclusion criteria: ◆ Children with seizure due to central nervous system infection (meningitis, encephalitis). ◆ Complex febrile seizures. ◆ Known case of seizure disorder. ◆ Seizure due to trauma, drug or toxin intake, CSOM. ◆ Children with seizure due to metabolic disturbances. ◆ Children with any chronic neurodevelopmental problems. ◆ Haematological problems like haemolytic anaemia, bleeding/coagulation disorders, haematological malignancy. ◆ Children on Iron supplementation. After exclusion, the remaining children are categorized according to various risk factors for recurrence of febrile seizures. RESULTS: The hemoglobin and serum ferritin levels were significantly lower in cases when compared to controls. Male gender and Temperature < 102.2°F were significant risk factors for simple febrile seizures as well as its recurrence. CONCLUSION: Iron deficiency anemia was more frequent among children with simple febrile seizures than those with febrile illness alone. The result suggests that Iron deficiency anemia may be a risk factor for simple febrile seizures

The effects of shoe temperature on the kinetics and kinematics of running

The aim of the current investigation was to examine the effects of cooled footwear on the kinetics and kinematics of running in comparison to footwear at normal temperature. Twelve participants ran at 4.0 m/s ± 5% in both cooled and normal temperature footwear conditions over a force platform. Two identical footwear were worn, one of which was cooled for 30 min. Lower extremity kinematics were obtained using a motion capture system and tibial accelerations were measured using a triaxial accelerometer. Differences between cooled and normal footwear temperatures were contrasted using paired samples t-tests. The results showed that midsole temperature (cooled = 4.21 °C and normal = 23.25 °C) and maximal midsole deformation during stance (cooled = 12.85 mm and normal = 14.52 mm) were significantly reduced in the cooled footwear. In addition, instantaneous loading rate (cooled = 186.21 B.W/s and normal = 167.08 B W/s), peak tibial acceleration (cooled = 12.75 g and normal = 10.70 g) and tibial acceleration slope (cooled = 478.69 g/s and normal = 327.48 g/s) were significantly greater in the cooled footwear. Finally, peak eversion (cooled = −10.57 ° and normal = −7.83°) and tibial internal rotation (cooled = 10.67 ° and normal = 7.77°) were also shown to be significantly larger in the cooled footwear condition. This study indicates that running in cooled footwear may place runners at increased risk from the biomechanical parameters linked to the aetiology of injuries

Electrodeposition of Sn, Se, SnSe and the material properties of SnSe films

Tin sulphide (SnS) films have been electrodeposited and the materials properties are reported, The potential-pH diagram of Sn and S in aqueous medium are superimposed to obtain the common immunity domains which predicts a pH value 1.5 and deposition potential of ·1.0 VseE for the stoichiometric deposition. Films are cathodically deposited on 5002 coated conducting glass substrates at bath temperatures 303-353 K. XRD studies show the polycrystalline nature with orthorhombic structure. The optical band gap of the snS film is 1.1 eV from the absorption studies. ESCA spectrum confirms the presence of Sn and S on the grey black sample. Uniform, smooth and pin hole free surface morphology is observed by SEM

Phase diagram and upper critical field of homogenously disordered epitaxial 3-dimensional NbN films

We report the evolution of superconducting properties with disorder, in 3-dimensional homogeneously disordered epitaxial NbN thin films. The effective disorder in NbN is controlled from moderately clean limit down to Anderson metal-insulator transition by changing the deposition conditions. We propose a phase diagram for NbN in temperature-disorder plane. With increasing disorder we observe that as kFl-->1 the superconducting transition temperature (Tc) and minimum conductivity (sigma_0) go to zero. The phase diagram shows that in homogeneously disordered 3-D NbN films, the metal-insulator transition and the superconductor-insulator transition occur at a single quantum critical point at kFl~1.Comment: To appear in Journal of Superconductivity and Novel Magnetism (ICSM2010 proceedings

Frequent JJ decoupling is the main origin of AC losses in the superconducting state

The origins of AC losses in the high Tc superconductors are not addressed adequately in literature. We found out, frequent Josephson Junction (JJ) decoupling (both intergranular and the interlayer) due to the flow of AC current is one of the main origins of the AC losses in high Tc superconductors. We have determined the AC losses in superconductors in the rf range by measuring the absolute value of non-resonant rf power absorbed by the samples. Our data shows that under certain conditions when both the number density of JJs present in the sample and the JJ critical current cross a threshold value, AC losses in the superconducting state keeps on increasing with decreasing temperature below Tc. The underlying mechanism is an interesting interplay of JJ coupling energy and the amplitude of rf voltage applied to the sample. The effect of an applied magnetic field, variation of rf frequency and temperature were studied in detail. To find out the exact relation between the JJ coupling energy, JJ number density, applied AC frequency, the amplitude of AC current and the AC losses in superconductors, we have studied samples of different crystalline properties, different grain sizes, pressurized with different pressure and sintered at different physical and chemical situations. The implementations of these results are discussed. These results have important implications for the understanding of the origin of AC losses and characterization of superconducting samples. In this paper we also extend the capability of the AC losses studies in superconductors for the characterization of materials for device applications.Comment: 20 pages, 5 figure

Phylogenetic analysis of Newcastle disease viruses isolated from waterfowl in the Upper Midwest Region of the United States

<p>Abstract</p> <p>Background</p> <p>This study was conducted to characterize Newcastle disease virus (NDV) isolates obtained from waterfowl from the Upper Midwest region of the United States. A total of 43 NDVs were isolated by inoculation of cloacal samples in embryonated chicken eggs. These isolates were obtained from 24 mallards, seven American green-winged teals, six northern pintails, four blue-winged teals, and two wood ducks. Partial sequences of fusion gene were analyzed to determine the pathotypes and genotypes involved.</p> <p>Results</p> <p>Deduced amino acid sequence of the cleavage site of fusion (F) protein revealed that all isolates had avirulent motifs. Of the 43 isolates, 23 exhibited sequence motif of ¹¹¹GGKQGRL¹¹⁷at the cleavage site, 19 exhibited ¹¹¹GEKQGRL¹¹⁷while one isolate showed ¹¹¹GERQGRL¹¹⁷. Phylogenetic analysis based on comparison with different classes of NDVs revealed that all 43 isolates clustered with class II NDVs and none with class I NDVs. Within class II, five isolates were phylogenetically close to genotype I NDVs while the remaining 38 were close to genotype II.</p> <p>Conclusion</p> <p>We conclude that more than one genotype of NDV circulates in waterfowl in the Upper Midwest region of the US. Continuous surveillance may help better understand the epidemiology of NDVs maintained in wild bird populations and their relationship to NDVs in domestic poultry, if any.</p

Do research papers provide enough information on design and material used in ankle foot orthoses for children with cerebral palsy? A systematic review

Objectives The purpose of this article is to determine how many of the current peer-reviewed studies of ankle foot or-thoses (AFOs) on children with cerebral palsy (CP) have included adequate details of the design and material of the AFO, to enable the study to be reproduced and outcomes clearly understood. Methods A thorough search of studies published in English was conducted in March 2015, with no restriction on dates, within all major databases using relevant phrases. These searches were then supplemented by tracking all key references from the appropriate articles identified. Study selection The inclusion criteria were as follows: (1) population - children with CP; (2) intervention - AFOs; and (3) outcome measure. One reviewer extracted data regarding the characteristics of the included studies, with the extracted data checked for accuracy and completeness by a second reviewer. None of the studies reviewed gave adequate details of the AFOs. Only 3.6% (n = 2) of papers tested the stiffness. Many studies (54.5%) did not describe the material used nor the material thickness (72.7 %). None of them gave any clinical justification for the chosen design of AFO. Conclusions There is a clear paucity of detail regarding the design and material used in AFOs on studies involving children with CP. Such a lack of detail has the potential to affect the validity of the reported outcomes, the ability to reproduce the studies and may misinform clinical practice