Multiple frequency optical mixer and demultiplexer and apparatus for remote sensing

A pulsed laser system includes a modulator module configured to provide pulsed electrical signals and a plurality of solid-state seed sources coupled to the modulator module and configured to operate, responsive to the pulsed electrical signals, in a pulse mode. Each of the plurality of solid-state seed sources is tuned to a different frequency channel separated from any adjacent frequency channel by a frequency offset. The pulsed laser system also includes a combiner that combines outputs from each of the solid state seed sources into a single optical path and an optical doubler and demultiplexer coupled to the single optical path and providing each doubled seed frequency on a separate output path

Fiber Laser Development for LISA

We have developed a linearly-polarized Ytterbium-doped fiber ring laser with single longitudinal-mode output at 1064nm for LISA and other space applications. Single longitudinal-mode selection was achieved by using a fiber Bragg grating (FBG) and a fiber Fabry-Perot (FFP). The FFP also serves as a frequency-reference within our ring laser. Our laser exhibits comparable low frequency and intensity noise to Non-Planar Ring Oscillator (NPRO). By using a fiber-coupled phase modulator as a frequency actuator, the laser frequency can be electro-optically tuned at a rate of 100kHz. It appears that our fiber ring laser is promising for space applications where robustness of fiber optics is desirable

Continuous Carrier Optical Phase Optometric Measurement over Coherent Optical Communication Link

An apparatus for measuring a distance between a first and second terminal includes a frame counter for determining a number of data frames traversing a distance between the first terminal 105 and the second terminal, a frame bit counter for determining a number of data clock bits offset between a transmitted data frame and a concurrently received data frame, a data clock phase detector for determining a phase difference between an RF data clock for the transmitted data frame and an RF data clock for the concurrently received data frame, and an optical carrier phase detector for determining a phase difference between an optical carrier used to transmit the transmitted data frame and an optical carrier for the concurrently received data frame. The distance between the first and second terminal is determined from a round trip transit time T between the first and second terminals

Logistic Growth Modeling with Markov Chain Monte Carlo Estimation

A new growth modeling approach is proposed to can fit inherently nonlinear (i.e., logistic) function without constraint nor reparameterization. A simulation study is employed to investigate the feasibility and performance of a Markov chain Monte Carlo method within Bayesian estimation framework to estimate a fully random version of a logistic growth curve model under manipulated conditions such as the number and timing of measurement occasions and sample sizes

Zwitterionic Surfactant as a Promising Non‐Cytotoxic Carrier for Nanoemulsion‐Based Vaccine Development

Motivated by the lack of noncytotoxic carriers in the current vaccine, we pursued the possibility of using a zwitterionic surfactant as a carrier to improve their delivery efficiency with antigen for a nanoemulsion‐based vaccine. We identified that a nanoemulsion formulation that consists of a specific zwitterionic surfactant can effectively mediate cellular uptake of antigen despite not having cytotoxicity as compared to a nanoemulsion that consists of a cationic surfactant. We report here the first study of a zwitterionic surfactant that consists of a positive charge in the outer layer of the polar head group and a hydrophobic tail is a promising approach for enhancing the carrier’s efficacy with no noticeable toxicity under experimental condition. However, zwitterionic surfactant that has positive charge in the outer layer with additional hydrophobicity due to the presence of aromatic ring had minimal cellular uptake and transfection efficacy.We report a nanoemulsion consists of a zwitterionic surfactant can effectively mediate cellular uptake of antigen despite not having cytotoxicity as compared to a NE consists of a cationic surfactant. ZI surfactant consists of a polar head, with positive charge in the outer layer has implications of developing next generation carrier to enhance the carrier‘s efficacy while improving tolerability for the development of NE‐based vaccine.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151273/1/slct201902737_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151273/2/slct201902737.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151273/3/slct201902737-sup-0001-misc_information.pd

Error Reduction Methods for Integrated-path Differential-absorption Lidar Measurements

We report new modeling and error reduction methods for differential-absorption optical-depth (DAOD) measurements of atmospheric constituents using direct-detection integrated-path differential-absorption lidars. Errors from laser frequency noise are quantified in terms of the line center fluctuation and spectral line shape of the laser pulses, revealing relationships verified experimentally. A significant DAOD bias is removed by introducing a correction factor. Errors from surface height and reflectance variations can be reduced to tolerable levels by incorporating altimetry knowledge and "log after averaging", or by pointing the laser and receiver to a fixed surface spot during each wavelength cycle to shorten the time of "averaging before log"

Reinforcement of dry spun polymeric fibers by cellulose nanocrystal

This study presents the development of composite polymeric fibers using cellulose nanocrystals (CNCs) as reinforcements. CNCs are a class of low cost, renewable and biodegradable materials with high mechanical properties and customizable surfaces. In this study, CNCs were successfully integrated into various polymeric fibers using the method of dry spinning in efforts to improve the fibers’ tensile strength and modulus. The effects of CNCs on two different polymer systems (cellulose acetate and polyvinyl alcohol) were studied. The surface morphologies, mechanical properties, and interactions between the CNCs and the polymer matrix within the fibers were investigated. The results of the characterizations show significant improvement in the tensile strength and modulus of both the cellulose acetate and polyvinyl alcohol fibers with low dosage of CNCs. The presence of CNCs increased the crystallinity of the polymer matrix. The effects of the high shear rates associated with dry spinning on the alignment and dispersion of the nanocrystals in the different systems were also studied. A micromechanical model was developed using data from both systems for the prediction of the fiber mechanical properties as a function of the alignment of the CNC rods

Origin and tuning of the magnetocaloric effect for the magnetic refrigerant MnFe(P1-xGex)

Neutron diffraction and magnetization measurements of the magneto refrigerant Mn1+yFe1-yP1-xGex reveal that the ferromagnetic and paramagnetic phases correspond to two very distinct crystal structures, with the magnetic entropy change as a function of magnetic field or temperature being directly controlled by the phase fraction of this first-order transition. By tuning the physical properties of this system we have achieved a maximum magnetic entropy change exceeding 74 J/Kg K for both increasing and decreasing field, more than twice the value of the previous record.Comment: 6 Figures. One tabl