Zigbee based wireless adjustable speed drive system

Indiana University-Purdue University Indianapolis (IUPUI)This thesis proposes a remotely controlled motor drive system which is able to supply a regulated voltage for both DC and AC motors. The proposed system integrates two different technologies, each of which belongs to the field of wireless communications and semiconductor power electronics. The introduction highlights the literature review and technical contributions in these two electrical engineering fields. The pulse width modulated control algorithm for speed control is discussed in detail. Incorporating the zigbee wireless technology into the motor drive system, for the speed control of an AC and a DC motor, by implementing digital pulse width modulation technique is the aim of this thesis. The main characteristics of the proposed system are: 1) its universal feature since it can feed either DC or AC motor without changing the hardware, 2) remotely controlled, which allows the end-user to control the motor speed safely from a remote distance, 3) flexibility in installation of the motor drives in areas that are not easily accessible by end-users, and 4) uninterrupted speed control for distance of up to few 100 feet

Curcumin reactivates epigenetically silenced tumor suppressor gene tissue factor pathway inhibitor-2 in hepatocellular carcinoma cells.

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide and the third most fatal, with a rising incidence in the US as a result of the increase in alcoholic liver disease and obesity. Current therapeutic strategies are unsatisfactory with poor treatment outcomes and efficacious therapies are acutely needed for better management of this deadly disease. Curcumin, a phenolic compound from the rhizome of the plant Curcuma longa has been shown to inhibit growth and induce cell death in various types of cancer cells including HCC. However, the anti-HCC mode of action of curcumin has not yet been elucidated. In HCC, aberrant promoter methylation and histone deacetylation are implicated in the inactivation of tumor suppressor genes which has a significant impact on carcinogenesis. Tissue factor pathway inhibitor-2 (TFPI-2), a Kunitztype serine protease inhibitor, is a tumor suppressor gene that is frequently epigenetically silenced in human HCC and HCC cell lines. Restoration of TFPI-2 expression in tumor tissue has been shown to not only inhibit invasion, tumor growth, metastasis and angiogenesis but also induce apoptosis. We examined the effects of curcumin on tumor suppressor genes in HCC and observed robust reactivation of TFPI-2 in HepG2 cells upon curcumin treatment. We confirmed that TFPI-2 was under epigenetic control in HepG2 cells by using demethylating agent 5-Aza-2\u27deoxycytidine (5-AZA) and histone deacetylase inhibitor trichostatin A (TSA), both of which induced gene expression. Further, we investigated the epigenetic modifications at the TFPI-2 promoter and the alterations induced by curcumin in these epigenetic states. Histone H3 acetylation at the transcription factor binding sites of the TFPI-2 promoter region was increased by curcumin and correlated with the induction of gene expression. The reactivation of TFPI-2 also corresponded with a decrease in cell invasiveness and increase in cell death in HepG2 cells. Overall, our data strongly suggest that curcumin can reverse the epigenetic alterations at the TFPI-2 promoter and thus, reactivate this silenced tumor suppressor gene. These results support a potential therapeutic role for curcumin in the management of HCC

Muscle activation patterns for voluntary isometric stiffness in human index finger

Humans can voluntarily control their finger stiffness for grasping and manipulation tasks. A long standing question in biomechanics is aimed at understanding the criterion used by the cenrtal nervous system to control the motor output of human limbs. Humans are known to voluntarily control their limb posture, end-tip force and stiffness. This thesis concerns itself with controlling stiffness in isometric conditions only. This work examines the variability of voluntary isometric stiffness modulation for the index finger at constant fingertip force. Previous studies either investigated muscle synergies responsible for different force-stiffness conditions or only measured behavioral measures of stiffness. However, the variability of stiffness for constant force condition was not explained. In this study, the stiffness of the index finger was modulated while maintaining a constant isometric fingertip force at 4 different force magnitudes and 2 different force directions. The muscle activations of 7 muscles that are related to the index finger were measured using surface electromyography (sEMG) sensors. Synergies estimated from a principal component analysis (PCA) using the recorded sEMG showed that the contribution of one synergy explains 80-95% of the variation in the data. The degree of alignment was used to analyze these stiffness synergies for different force conditions. The minimum mean value of degree of alignment was found for the comparison between synergies at high forces. However, comparison of synergies at lower forces showed that the stiffness synergy varies more with the forcing direction than it does with force magnitude. These results show the existence of a stiffness synergy to modulate the stiffness for individual force direction regardless of the magnitude of force level. Although the results at higher forces do not agree with this conclusion, stiffness modulation is prominent only at lower forces. This result gives an insight into what muscle synergies are important for modulating the fingertip stiffness. It can prove useful in robotics applications to simplify stiffness modulation without explicitly calculating inverse kinematics and also in restoring stiffness modulation after hand injuryMechanical Engineerin

SPATIO-TEMPORAL VARIATION IN ACTIVATION INTERVALS DURING VENTRICULAR FIBRILLATION

Spatio-temporal variation in activation rates during ventricular fibrillation (VF)provides insight into mechanisms of sustained re-entry during VF. This study had three objectives related to spatio-temporal dynamics in activation rates during VF. The first objective was to quantify spatio-temporal variability in activation rates,that is, in dominant frequencies, computed from epicardial electrograms recorded during VF in swine. Results showed that temporally and spatially, dominant frequencies variedas much as 20% of the mean dominant frequency, and the mean dominant frequencies increased during first 30 sec of VF. These results suggest that activation rates are nonstationary during VF. The second objective of the study was to develop a new stimulation protocol for quantifying restitution of action potential duration (APD) by independently controlling diastolic intervals (DI). A property of cardiac cells that determines spatio-temporal variability in dominant frequencies is restitution of APD, which relates APD to the previous DI. Independent control of DI permits explicit determination of the role of memory in restitution. Restitution functions quantified using mathematical models of activation and our stimulation protocol, showed significant hysteresis. That is, for adiastolic interval, the action potential durations were as much as 15% longer during periods when the DI were decreasing than when the DI were increasing. We verified the feasibility of implementing our protocol experimentally in isolated and perfused rat hearts with action potentials recorded using floating glass microelectrodes. The third objective of our study was to verify that spatio-temporal variability in dominant frequencies during VF could be modified using spatially distributed pacing strength stimuli. Simulated VF was induced in 400x400 and 400x800 matrices of cells. Electrical function of cells was simulated using the Luo-Rudy model. Stimulators were arranged in the matrices such that there were 5 rows of line stimulators. Results showed that it was possible to modify activations in almost 54% of the area and to modify spatio-temporal variability in activation during VF into a desired pattern by the use of synchronized pacing from multiple sites. These results support further exploration of distributed stimulation approach for potential improvements in defibrillation therapy

Charge-transfer and other excitonic state in conjugated polymer : fullerene blends-implication in photovoltaics

"May 2014."Dissertation Supervisor: Dr. Suchi Guha.Includes vita.Over the last few decades there has been tremendous progress in organic photovoltaics (OPVs), with efficiencies reaching over 10%. Still, many factors including the origin and the dynamics of charge carrier involved are debatable. New and sensitive techniques are constantly being devised to identify the origin of free charges. At the same time, a lot of research has also been devoted to synthesize low bandgap material such that its absorption spectra overlap with that of the solar spectrum. The most important hindrance in organic semiconductors is the formation of bound electron-hole (exciton) charge pair upon photoexcitation. Additional energy is required to dissociate the bound pair to generate free charges for photovoltaic application. The most popular and efficient way to dissociate excitons is to fabricate a bulk heterojunction solar cell, which comprises of a blend of at least two polymers: one donor and the other acceptor. It is very well established that the presence of fullerene (acceptor) helps in transfer of the negative charges from the donor polymer to fullerene, making the exciton slightly less bound. The nanometer scale islands further help in migration of charges. A crucial aspect of our studies has been evaluating the role of various excitonic states such as charge-transfer and triplet excitonic states in device efficiencies. The focus of this work was on diketopyrrolopyrrole (DPP)- based donor-acceptor (D-A) type conjugated copolymers which have low bandgap energies and have been known to show high efficiency in organic photovoltaics. These copolymers have D-A unit present in the same chain, which lowers the optical bandgap of the material. Variation of either the donor or the acceptor fraction offers an option to tune the optical bandgap by using the same D-A chromophores. The D-A configuration also results in the separation of positive and negative charges within the same polymeric chain, which is the intramolecular charge-transfer excitonic state. We analyze the intramolecular charge-transfeIncludes bibliographical references (pages 125-136)

ERIOCAULACEAE OF RICE FIELDS OF BILASPUR IN CHHATTISGARH

During our field visits in Rice fields of Bilaspur, Chhattisgarh we found 3 species of Eriocaulon belonging to family Eriocaulaceae, commonly known as ‘Pipe wort’ family (Haines,1921). Though it was not very common, it’s interesting and complicated morphological features made us to view this species from a different angle. These have been discussed in present paper.Keys words:  Eriocaulon, rice field, Pipeworts, Eriocaulon quinguangulare

Theoretical Consideration of the Influence of Reforming Processes on the Fracture Strength of Solids Technical Report No. 105

Reformation processes effect on stress time-to- fracture behavior of solid

On Internal Fracture of Solids

Initiation and propagation of internal fracture in solid