Given the rapid aging of the world's population, improvements in technology for automation of patient care and documentation are badly needed. This project is based on previous research that demonstrated a "smart" bed that can non-intrusively monitor a patient in bed and determine a patient's respiration, heart rate and movement without intrusive or restrictive medical measurements. The "smart" bed is an application of spatially distributed integrating fiber optic sensors. The basic concept is that any patient movement that also moves an optical fiber within a specified area will produce a change in the optical signal. A statistical mode (STM) sensor and a high order mode excitation (HOME) sensor were previously investigated, based on which the author developed the present design including both modal modulation approaches.

Development was made in both hardware and software for the combined STM/HOME sensor: a special lens system was installed allowing only the high order modes of the optical fiber to be excited and coupled into the sensor; computer-processing method was used for handling output from the dual STM-HOME sensor, which would offer comprehensive perturbation analysis for more reliable patient monitoring.

Experimental results of simulating human body breathing and heartbeats by periodic mechanical perturbations are also presented, and the relative advantage and drawbacks of the two modal modulation approaches are discussed.

Borexino is a liquid scintillator detector designed to measure the flux, and energy spectrum, of the mono-energetic neutrinos produced by electron capture on ⁷Be in the Sun's core. Borexino affords the real-time measurement of the ⁷Be neutrino energy spectrum to the lowest energy threshold to-date, thus allowing us to probe new physics. However, the low energy threshold, coupled with a low count rate, requires Borexino to have extremely low backgrounds, and additionally requires us to have an excellent understanding of the backgrounds that do exist. The purification techniques employed for the scintillator have lowered the radioactive contaminants to levels never before achieved; however, we must still apply cuts to the data.

At Virginia Tech, we have developed an internal source calibration program that employs radioactive and optical sources, and will give us a thorough understanding of both the pulse shape discrimination efficiency, as well as the energy and time response of Borexino. The radioactive sources allow us to obtain the energy scales for alpha, beta, and gamma backgrounds present in the detector. When the calibration sources are used in conjunction with an accurate source location system, we can discover, and correct for, any spatial or energy dependencies found.

Borexino is a liquid scintillator detector that will measure the neutrino energy spectrum to the lowest energy threshold to date. It has been designed to measure the flux of the mono-energetic neutrinos produced by electron capture on ⁷Be in the Sun's core, which will produce a Compton-like edge in the energy spectrum. Because of the low count rate, Borexino requires extremely low backgrounds, and a good understanding of the backgrounds that do exist. Although the purification techniques used for the scintillator lowered the radioactive contaminates to levels never before achieved, cuts must still be made to the data.

At Virginia Tech we have developed an internal source calibration program that will be able to give us a thorough understanding of both the pulse shape discrimination efficiency and the energy and time response of Borexino. It will also be able to give us the energy scales for the alphas, betas, and gammas. When the calibration source is used in conjunction with an accurate source location system any spatial dependencies can be found. A source location system consisting of seven CCD cameras arranged around the inside of the detector will be used to determine said dependencies. Inserting calibration sources into the detector has the potential to introduce contaminates. To avoid contamination, a source insertion system was developed for both the internal and external calibration sources.

Recent research has looked into the possibility of utilizing the spins of electrons in semiconductors as a means of storing and transferring information. Spin coherence, the alignment of the spins of electrons in the material, is an important property governing how far spin-encoded information can travel and for how long it can last. Spin coherence can be measured by Time-Resolved Faraday Rotation. In this method, electrons are excited by a "pump" laser beam with in a magnetic field, causing spins to align. A "probe" laser beam, circularly polarized, will experience a rotation in the polarization when passing through the material. The lifetime of the coherent spins can be determined by varying the delay between pump and probe beams.

Another technique, Resonant Spin Amplification, can be used when the spin lifetime is longer than can be measured by time-resolved Faraday rotation.

KOPIO is an experiment designed to search for the CP-symmetry-violating reaction K₀→π₀+ν+ν, which has the potential to explain the observed lack of symmetry between matter and antimatter in our universe. The K₀→π₀+ν+ν reaction is exceedingly rare, with a branching ratio of (2.6±1.2)×10^-11. The rareness of this reaction means two things: 1) that we need prodigious numbers of kaons, and 2) that the multitude of "improper" decays will have to be screened out by means of a veto detector system being designed here at Virginia Tech.

This detector must be able to detect the passage of daughters of the undesired decay reactions (charged particles and gammas). It must be operational inside a magnetic field, and must have signal timing fast enough to accommodate the rate at which these decays occur. I will present a brief overview of the KOPIO experiment, as well as the design methodology, construction, and testing of a prototype detector module. I will also discuss other potential uses for such detector technology.

This seminar will present the difficulties with detecting Low energy neutrino reactions with indium loaded scintillator, and how we at Virginia Tech are developing methods to accomplish this goal.

Complex networks, describing a wide variety of systems, are common in nature. In this talk, we will introduce three types of networks, i.e. random graph, small-world networks and scale-free networks. We will focus on the scaling properties of the small-world networks, and give some interesting relation between structure of the networks and the random walk problem.

Given the demand from several fields of work, new and more reliable techniques for cell manipulation are being developed. This research project will work to better characterize and perfect one relatively new process in this field. This process uses high energy pulsed lasers to penetrate living cells without harming the cell. In this presentation we will discuss the technique of penetrating living cells with high energy pulsed lasers. Our work here at Virginia Tech will include the insertion of quantum dots into the living cells in order to obtain information about the cells. How this method works, and previous research will be discussed along with our future plans here at Virginia Tech.

Three phases of matter were known to human civilization from time antiquity. With the advent of thermodynamics people tried to understand matter and its different forms from a macroscopic and empirical point of view. That was probably the first sincere attempt to understand phase transition. But it was in no way rigorous.

Statistical Mechanics on the other hand was the first decisive tool which helped people probe deeper down and laid the first formal structure in explaining thermodynamics. People endowed with this new tool plunged into the challenges of explaining phase transition and found themselves entangled in series of complicated questions. My talk will be a journey through history; how we came to better understand the world around us and what was the road that led us to the final understanding of phase transition.

Interstellar space is not a vacuum! The material in these regions is known as the interstellar medium (ISM) and is composed of several components. Hydrogen, the most common component (by both mass and volume), exists in several forms. The Virginia Tech Spectral-line Survey (VTSS) is a wide-field image survey of the Galaxy's warm ionized interstellar medium (WIM, 10,000 K plasma). The results of this survey will provide insights to general ISM phenomena (e.g., distribution of the WIM and its relation to other phases, dynamical features, ionization and heating of the ISM), radio wave scattering by the ISM and searches for small-scale anisotropies in the CMB, to name a few examples.

This brief presentation will highlight some of the questions this survey will hope to answer as well as give an overview of the automation of the VTSS.

The canonical commutation relations in ordinary quantum mechanics can be modified to account for the possible existence of an absolute minimal length, suggested by quantum gravity and string theory. This modified, "minimal length" quantum mechanics is an excellent testing ground for such hypotheses as it is conceptually no more sophisticated than regular quantum mechanics. In this talk I will calculate the minimal-length corrections to the Hydrogen atom spectrum, and compare it to experimental data in order to obtain an upper bound on the allowable size of such a minimal length.

The primary purpose of this project is to explore how the adhesion of an anti-reflective (AR) coating fabricated by ionic assembly of silica nanoparticles can be improved without degrading the optical quality of the film. The approach taken is to utilize a diazo-resin (DAR) in the ionic assembly of the silica nanoparticles and convert the weak ionic bond to a stronger covalent bond by UV induced cross-linking. The optical quality and adhesive strength of silica/DAR cross-linked films depend on several process variables (factors). The statistical technique, fractional factorial design, is used to identify the statistically significant factors. In addition, the model derived from the factorial analysis relating the response variables, optical quality and adhesive strength, to the significant factors is used to draw provisional conclusions regarding factor values that maximize the response variables. Finally, this study explores whether it is feasible to minimize the interactions between the thickness of the film and the other significant factors.

For those familiar with he standard algebraic formulation of quantum mechanics, it may come as little surprise that the essential elements of the theory do not require an entire Hilbert space to capture. In fact, if one considers the normalized vectors in Hilbert space as points in some other space, the basic components of quantum theory take on a geometrical flavor. This flavor can be codified as an independent formulation of quantum mechanics. I would like to introduce the geometric formulation and compare it to the algebraic formulation as well as highlight the similarities between it and classical mechanics.

The Totally Asymmetric Simple Exclusion Process (TASEP) is one of the simplest and most well-understood processes. Exact solutions are available for a homogeneous system. We expand the TASEP model to an "almost homogeneous" system with a few blockages to explore the changes in the density profiles and the currents. As the protein production process resembles this TASEP model and the local translation rates are related to correponding codon concentrations, TASEP serves as a good model to simulate this process and provides us with some interesting insights in predicting the protein production rate. In the talk, some preliminary simulation results will be presented. Interpretations of the results using mean field theory will be discussed.

Many physical systems can be characterized by a slowly varying time dependence. In particular, one may consider a system defined by a slowly varying potential that transitions from a double well into a single well. For a classical system, model potentials inspired by proton transfer in the F + HCl → FH + Cl reaction were studied.

These potentials were found to have three especially noteworthy properties. First was that these potentials are resistant to standard multi-scale perturbation methods. Second, a peculiar independence of the choice of time scale was found, and third was the presence of a characteristic accelerated reference frame. Based on this study, a method for finding an approximate solution was proposed and is currently being pursued.

Surface Plasmon is the quanta of the collective motion of electrons at a metal/dielectric interface. Localized Surface Plasmon Resonance (LSPR) can be excited in some noble metal nanostructures. Silver nanoparticle (truncated tetrahedron) arrays are fabricated by nanosphere lithography (NSL). The extinction spectroscopy of these nanoparticle arrays suggests that several plasmon modes are present in our current silver nanostructures. Relationship between the resonance wavelength and the nanoparticle height is investigated as well as the sensitivity of the resonance wavelength to the external environment. Such nanostructure-based LSPR can find application in the nonlinear optical phenomena and nanosensors.

Optical biosensors are mechanisms that have the ability to revolutionize how diagnostics, genomics, proteomics, and environmental monitoring are performed. In addition, there is a growing threat of weaponized pathogenic microorganisms (i.e. the anthrax attacks in the U.S. in 2001), which biosensors can help alleviate. Biosensors also have significant applications in the medical field, such as monitoring diabetic patients' glucose levels, drug discovery, and cancer treatment efficacy. They can also aid in monitoring food safety and detect environmental pollution.

One main area of interest is the Surface Plasmon Resonance (SPR) biosensor, which has some downfalls. It is expensive, delicate, and non-portable. An alternative to SPR that eliminates the aforementioned disadvantages is Ionic Self-Assembled Multilayers (ISAMs) adsorbed on Long Period Fiber Gratings (LPGs). The ISAM technique is a layer-by-layer deposition technique that creates thin films on the nanoscale level. LPGs are very sensitive to physical changes in the surrounding environment. LPGs embedded in optical fibers produce a noticeable decrease in the transmitted light intensity at a certain wavelength, called the attenuation wavelength. The attenuation wavelength shifts as a function of the environment exterior to the optical fiber cladding. For this reason, LPGs have been considered for sensing applications. Further research on biosensors will allow for improvements on their portability, sensitivity, and reliability.

The Belle experiment was built to carry out precision studies of B meson decays, in particular to search for CP violation in the B meson system, and to measure the interior angles of the CKM unitarity triangle, Φ₁, Φ₂, and Φ₃.

The method extraction of various CKM parameters and recent results from Belle experiment will be explained.

Adiabatic Demagnetization Refrigeration (ADR) is the oldest method to achieve milli-Kelvin temperatures. It is well studied and widely used until more efficient methods of achieving temperatures below 50 mK were introduced.

The cryostat should be capable of reaching very low temperatures; therefore it is a big challenge to reduce the heat transfer from the cooling stages which are at higher temperatures to the sample space which is at ~ 50 mK. In my talk I will give an overview of the general principles and techniques used for the design and construction of an ADR Cryostat. I will discuss some of the problems we face with choice of proper materials which is in direct relation to thermal insulation and heat dissipation, heat switch design and operation, as well some applications of ADR cryostats.

Recent neutrino oscillation experiments unambiguously showed that neutrinos are massive particles. The obvious question here for theoretical physicists is how to incorporate the description of the neutrino masses in the framework of the Standard Model of Elementary Particles. In my talk I am going to discuss the possible answers to this question (Dirac and Majorana type mass terms) and show an explicit example of a non see-saw type neutrino mass texture (a so-called Okamura Model) which can explain the observed mass spectrum of the light neutrinos and in addition to that predicts the existence of the heavy neutrinos at the TeV energy scale. This energy scale will soon be accessible for experimentalists (LHC) and the heavy neutrinos might be produced in a large amount. The question is whether or not it will be possible to detect them. To answer this question we need to know the lifetimes of the heavy neutrinos. I will present a convenient parametrization of the Okamura Model then show the result of my lifetime calculation and discuss its consequences.

CP violation in the leptonic sector has not been observed yet. Very strong constraints come from the current limits on the electric dipole moment (EDM) of the electron (and muon). In the recent model proposed by Takeuchi and others to explain the NuTeV anomaly, TeV Right Handed Neutrinos (RHN's) mix heavily with the standard model neutrinos in a specific sea-saw like texture. Among the phenomenological consequences of this model is the possibility of a large CP violation in the leptonic sector.

The Majorana nature of the (RHN) results in new (two loop) diagrams leading to non-zero CP violation. The large mixing of the RHN's can result in a huge enhancement to the value of CP violation and lepton EDM produced by these diagrams.

I will explain what CP violation is, how it relates to EDM, and how Majorana TeV RHN's can result in a relatively large EDM for leptons.