Use of Photo Isomers to Enhance the Removal of Lignin From Woody Biomass Hydrolysate

In this investigation we propose a novel method to enable precipitation of desired solutes using photo-isomers in the extraction solvent. This photo-switchable solvent would enable dissolution or precipitation of desired components using alternating UV or visible light to modify the solubility of the compounds of interest. Three photo-isomers namely native azobenzene, diethoxy azobenzene and diethylamino azobenzene were studied in three different organic solvents: medium chain length alcohol, ethanol and acetone. It was found that among the different combinations of solvent and photo-isomer, acetone and the 4,4’-diethoxy azobenzene solution was most efficient at precipitating dissolved lignin in response to UV light exposure. This system was able to precipitate 20% of the initial amount of lignin added

Optimization Schemes for Efficient Multiple Exciton Generation and Extraction in Colloidal Quantum Dots

Multiple exciton generation is a process in which more than one electron hole pair is generated per absorbed photon. It allows us to increase the efficiency of solar energy harvesting. Experimental studies have shown the multiple exciton generation yield of 1.2 in isolated colloidal quantum dots. However real photoelectric devices require the extraction of electron hole pairs to electric contacts. We provide a systematic study of the corresponding quantum coherent processes including extraction and injection and show that a proper design of extraction and injection rates enhances the yield significantly up to values around 1.6.Comment: 5 pages, accepted by The Journal of Chemical Physic

Disease activity and biologic use in patients with psoriatic arthritis or rheumatoid arthritis.

To compare disease burden and biologic use among psoriatic arthritis (PsA) or rheumatoid arthritis (RA) patients recruited to the Corrona registry. Retrospective study of patients with PsA or RA enrolled in Corrona between January 2002 and March 2013 and grouped in 2-year intervals. Clinical outcomes and biologic use were assessed. Biologic use increased over time in both cohorts, with 62 and 52% of patients with PsA and RA, respectively, receiving biologics by 2012-2013. However, 25 and 35% of patients with PsA and RA, respectively, continued to experience moderate/high disease activity. Overall, the progressive increase in biologic use accompanied progressive decreases in Clinical Disease Activity Index (from 14.2 to 10.4 for RA, and 12.4 to 8.1 for PsA) and mean Health Assessment Questionnaire score (from 0.36 to 0.34, and 0.3 to 0.24). Mean patient pain, the proportion of patients reporting morning stiffness, and the mean duration of morning stiffness remained similar for both cohorts. PsA and RA treated in the rheumatology setting had a comparable impact on patient quality of life and functional ability. Disease burden improved with increased biologic utilization in both groups; however, moderate/severe disease remains in a significant proportion of PsA and RA patients

Structural and Physical Properties of CaFe4As3 Single Crystals

We report the synthesis, and structural and physical properties of CaFe4As3 single crystals. Needle-like single crystals of CaFe4As3 were grown out of Sn flux and the compound adopts an orthorhombic structure as determined by X-ray diffraction measurements. Electrical, magnetic, and thermal properties indicate that the system undergoes two successive phase transitions occurring at TN1 ~ 90 K and TN2 ~ 26 K. At TN1, electrical resistivities (\rho(b) and \rho(ac)) are enhanced while magnetic susceptibilities (\chi(b) and \chi(ac)) are reduced in both directions parallel and perpendicular to the b-axis, consistent with the scenario of antiferromagnetic spin-density-wave formation. At TN2, specific heat reveals a slope change, and \chi(ac) decreases sharply but \chi(b) has a clear jump before it decreases again with decreasing temperature. Remarkably, both \rho(b) and \rho(ac) decrease sharply with thermal hysteresis, indicating the first-order nature of the phase transition at TN2. At low temperatures, \rho(b) and \rho(ac) can be described by {\rho} = {\rho}0 + AT^\alpha ({\rho}0, A, and {\alpha} are constants). Interestingly, these constants vary with applied magnetic field. The ground state of CaFe4As3 is discussed.Comment: 15 pages, 8 figures, Submitted to Physical Review

Improving LIGO calibration accuracy by tracking and compensating for slow temporal variations

Calibration of the second-generation LIGO interferometric gravitational-wave detectors employs a method that uses injected periodic modulations to track and compensate for slow temporal variations in the differential length response of the instruments. These detectors utilize feedback control loops to maintain resonance conditions by suppressing differential arm length variations. We describe how the sensing and actuation functions of these servo loops are parameterized and how the slow variations in these parameters are quantified using the injected modulations. We report the results of applying this method to the LIGO detectors and show that it significantly reduces systematic errors in their calibrated outputs.Comment: 13 pages, 8 figures. This is an author-created, un-copyedited version of an article published in Classical and Quantum Gravity. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from i

ADEQUACY OF EXISTING LIGHT TIMBER SHEAR WALLS TO BRACE STEEL FRAMES IN RENOVATION CONSTRUCTION

A lateral load resisting system (LLRS) is an interconnected framework in the building that works together to resist the lateral loads, both wind and seismic, acting on the building. A shear wall is a part of the LLRS which transfers the lateral load to the foundation of the building. Currently, the provision from IBC and ASCE 7-16 suggests the selection of adequate stiffness, dimension, and type of shear walls based on the given lateral loads. There has been a rise in the amount of building renovations since the 1980’s. In 2019, expenditures in home improvements were around $262 billion with$17 billion spent in major structural work. These numbers have increased by roughly 3% in 2022. One common type of renovation is to open a floorplan by removing an interior load bearing wall and replacing it with a steel frame structure. This frame will require adequate lateral stability to be provided by the LLRS of the building structure. Currently, the AISC Steel Construction design code requires a certain amount of lateral stiffness based on the geometry of the frame and the gravity loads being carried by the frame. However, many times it is just assumed that the LLRS of the building provides this required stiffness without it being vi checked. This thesis will examine the adequacy of light framed timber shear walls, designed in accordance with IBC specifications based on wind loading, to provide adequate stiffness, based on AISC specifications, to a steel frame structure used in a common retrofitting of a building. Variables related to building location which impacts gravity loads (e.g., dead load, live load and snow load) and lateral loads (e.g. wind), building size and tributary area of the steel frame were used to determine if shear wall design based on the IBC code is adequate for lateral stiffness of the steel frame in all cases. The numerical analysis showed that for each of the cases analyzed in this thesis that the timber shear walls designed in accordance with the IBC under a given wind loading will provide the required lateral stiffness to an interior steel frame used in renovations of a structure

Multiple exciton generation in nano-crystals revisited: Consistent calculation of the yield based on pump-probe spectroscopy

Multiple exciton generation (MEG) is a process in which more than one exciton is generated upon the absorption of a high energy photon, typically higher than two times the band gap, in semiconductor nanocrystals. It can be observed experimentally using time resolved spectroscopy such as the transient absorption measurements. Quantification of the MEG yield is usu- ally done by assuming that the bi-exciton signal is twice the signal from a single exciton. Herein we show that this assumption is not always justified and may lead to significant errors in the estimated MEG yields. We develop a methodology to determine proper scaling factors to the signals from the transient absorption experiments. Using the methodology we find modest MEG yields in lead chalcogenide nanocrystals including the nanorods