Dispersion States and Surface Characteristics of Physically Blended Polyhedral Oligomeric Silsesquioxane/Polymer Hybrid Nanocomposites

Control of dispersion and segregation states of nanostructured additives is one of the biggest challenges in realizing the optimum potential of high-performance hybrid polymer nanocomposites. Polyhedral oligomeric silsesquioxane (POSS) nanostructured chemicals, with their hybrid organic-inorganic nature and flexible functionalization with a variety of organic substituents, yield possibilities to control dispersion and tune compatibility in a wide range of polymer systems. The overall goal of this research is to investigate the fundamental parameters that influence the dispersion and segregation states of POSS nanostructured chemicals and to understand chain dynamics and conformations in physically blended POSS hybrid polymer nanocomposites (HPNC\u27s). Multiple structural and mechanical factors influencing macro to nano scale surface and bulk properties were successfully investigated and correlated. A strategy based on thermodynamic principles for selective control of POSS dispersion states in a given polymer matrix is developed and discussed. This dissertation consists of eight chapters. Chapter 1 provides a detailed introduction to the development and current research interest in POSS/polymer nanocomposites. This chapter also discusses limitations of current advanced nanoprobe techniques. Chapter 2 establishes the overall goal of this research and specific research objectives. Chapter 3 establishes the preferential surface migration behavior of physically dispersed, non-reactive, closed cage octaisobutyl POSS (Oib-POSS) in a nonpolar polypropylene matrix. Furthermore, influence of POSS surface segregation on the surface properties, especially nano-tribomechanical behavior is also discussed. Chapter 4 expands the studies by melt blending two different types of POSS molecules, a nonreactive, closed cage Oib-POSS and an open cage trisilanolphenyl POSS (Tsp-POSS), in a nylon 6 matrix. This chapter discusses the morphology, nano-dispersion and macro- to nanoscale tribomechanical characteristics in relation to the POSS structures. Chapter 5 probes the molecular miscibility, solution and solid-state chain dynamics in polystyrene solution blended with Oib- and Tsp-POSS based on classical thermodynamic principles. Chapter 6 extends the learnings from chapter 5 to utilize POSS as a dispersion aid to disperse Ti02 nanoparticles in polypropylene. Chapter 7 explores the surface properties of fluorinated and non-fluorinated POSS coated fabrics. Finally, chapter 8 explores a nature-inspired route to modify polymer surfaces utilizing hydrophobin proteins and their impact on surface morphology and nanotribological characteristics

PLA Microparticles for Pulmonary Delivery of AntiTB drugs: Biodistribution study

A dry powder inhalable (DPI) microparticles comprising anti-tuberculosis drugs incorporated in biodegradable polymers was developed for the treatment of pulmonary tuberculosis (P. Muttil _et al_. 2007). Poly L-lactic acid (PLA) microparticles incorporating a high payload of rifabutin and isoniazid were fabricated by spray drying (Buchi 190). Microparticles were composed of PLA and the drugs (rifabutin and isoniazid) at a 2:1:1 weight ratio. Microparticles of desired high encapsulation efficiency and sustained release characteristics were produced having a diameter range of 2-10 µm (Malvern Mastersizer 2000). Differential scanning calorimetry (DSC) was carried out to study drug polymer interaction. The time course of tissue biodistribution following a single inhalation dose of microparticles was evaluated. 
Thirty-two BALB/c mice were divided into groups of four and administered the DPI using an in-house (nose only) apparatus (Kaur _et al_. 2008; Verma _et al_. 2008). A validated HPLC method was used for determination of rifabutin and isoniazid in the lungs (target organ), liver and kidneys (major sites of toxicity) at different time-points after inhalation. A comparison was made with mice receiving free drugs (intravenous) at equivalent doses. Deposition of microparticles in lungs of mice following aerosolization was also evaluated. Pharmacokinetic parameters in different organs were calculated using WinNonlin software version 5.2. Area under the concentration-time curve observed (AUC~obs~), C~max~, half-life (t~½~) and clearance (CL) in lungs following inhalation /intravenous administration were:
*Rifabutin*: AUC~obs~-96h= 1697.39 ±154.67 (187.63 ±23.93) µg/ml^-1^hr^-1^; C~max~ = 33.42±3.80 (4.17±0.31) µg.ml^-1^; t~½~= 78.08±9.42 (34.00 ±3.31) and Cl= 1.16±.22 (0.68 ±0.45) ml.h^-1^.
*Isoniazid*: AUC~obs~-24h= 566.31±123.96 (99.85 ±14.24) µg/ml^-1^hr^-1^; Cmax= 24.02±1.71 (8.16±0.93) µg.ml^-1^; t~½~= 25.88±12.16 (6.45±3.24) h; and Cl= 5.47±1.30 (0.96±0.14) ml.h^-1^.
The relative bioavailability of both drugs incorporated in microparticles was significantly higher compared with free drugs. Peak levels of isoniazid and rifabutin in lungs (target organ) were much higher than those in the liver and kidney of mice in case of inhalation as compared to intravenous administration. Inhalation of microparticles resulted in targeting both drugs to the lungs, with the effect being more pronounced in the case of rifabutin than isoniazid. High and prolonged drug concentrations and increased AUC values (~9-fold and ~6 fold increase of rifabutin and isoniazid in case of lungs) with respect to free drugs were observed. Significant decrease in drug concentration was found in the liver and kidneys. Drug levels were maintained above the minimum inhibitory concentration (MIC) in organs through out the study after administration of encapsulated drugs. Based on favorable biodistribution kinetics, these microparticles hold great potential in reducing dosing frequency and toxicity of antituberculosis drugs.
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Highway Entrance Ramp Monitoring and Control using Soft Computing Techniques

Highway entrance ramp monitoring and control is used to regularize the flow of traffic entering through the highway entrance ramps. It detects the flow of traffic enter ing through the highway ramp monitoring system and controls the flow of traffic using ramp monitoring and control algorithm. This algorithm employs some soft computing techniques which is a suitable choice due to the imprecise information and the level of inaccuracy in the monitoring data available. The use of AI - based search algorithms to calibrate the parameters of a micro - simulation model or estimate the dynamic demand needed to run the model is an area that has received significant attention from researchers recently. Use of soft computing techniques improves the traffic flow as also increases the efficiency of the traffic system with enhanced control a nd safety

Modeling the effects of insecticides and external efforts on crop production

In this paper a nonlinear mathematical model is proposed and analyzed to understand the effects of insects, insecticides and external efforts on the agricultural crop productions. In the modeling process, we have assumed that crops grow logistically and decrease due to insects, which are wholly dependent on crops. Insecticides and external efforts are applied to control the insect population and enhance the crop production, respectively. The external efforts affect the intrinsic growth rate and carrying capacity of crop production. The feasibility of equilibria and their stability properties are discussed. We have identified the key parameters for the formulation of effective control strategies necessary to combat the insect population and increase the crop production using the approach of global sensitivity analysis. Numerical simulation is performed, which supports the analytical findings. It is shown that periodic oscillations arise through Hopf bifurcation as spraying rate of insecticides decreases. Our findings suggest that to gain the desired crop production, the rate of spraying and the quality of insecticides with proper use of external efforts are much important

Soft-collinear effects in prompt photon production

We extend next-to-leading logarithmic threshold and joint resummation for prompt photon production to include leading collinear effects. The impact of these effects is assessed for both fixed-target and collider kinematics. We find them in general to be small, but noticeable.Comment: 14 pages, 12 figures, added comment on fragmentation contribution and one more reference. Version to appear in Phys. Rev.

Robust Correlated Equilibrium: Definition and Computation

We study N-player finite games with costs perturbed due to time-varying disturbances in the underlying system and to that end we propose the concept of Robust Correlated Equilibrium that generalizes the definition of Correlated Equilibrium. Conditions under which the Robust Correlated Equilibrium exists are specified and a decentralized algorithm for learning strategies that are optimal in the sense of Robust Correlated Equilibrium is proposed. The primary contribution of the paper is the convergence analysis of the algorithm and to that end, we propose an extension of the celebrated Blackwell's Approachability theorem to games with costs that are not just time-average as in the original Blackwell's Approachability Theorem but also include time-average of previous algorithm iterates. The designed algorithm is applied to a practical water distribution network with pumps being the controllers and their costs being perturbed by uncertain consumption by consumers. Simulation results show that each controller achieves no regret and empirical distributions converge to the Robust Correlated Equilibrium.Comment: Preprint submitted to Automatic