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DOE OSTI2017

Small-angle light scattering symmetry breaking in polymer-dispersed liquid crystal films with inhomogeneous electrically controlled interface anchoring

We have described the method of analyzing and reporting on the results of calculation of the small-angle structure of radiation scattered by a polymer-dispersed liquid crystal film with electrically controlled interfacial anchoring. The method is based on the interference approximation of the wave scattering theory and the hard disk model. Scattering from an individual liquid crystal droplet has been described using the anomalous diffraction approximation extended to the case of droplets with uniform and nonuniform interface anchoring at the droplet–polymer boundary. The director field structure in an individual droplet is determined from the solution of the problem of minimizing the volume density of the free energy. The electrooptical effect of symmetry breaking in the angular distribution of scattered radiation has been analyzed. This effect means that the intensities of radiation scattered within angles +θ{sub s} and–θ{sub s} relative to the direction of illumination in the scattering plane can be different. The effect is of the interference origin and is associated with asymmetry of the phase shift of the wavefront of an incident wave from individual parts of the droplet, which appears due to asymmetry of the director field structure in the droplet, caused by nonuniform anchoring of liquid crystal molecules with the polymer on its surface. This effect is analyzed in the case of normal illumination of the film depending on the interfacial anchoring at the liquid crystal–polymer interface, the orientation of the optical axes of droplets, their concentration, sizes, anisometry, and polydispersity.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2022

Gravitizing the quantum

We discuss a new approach to the problem of quantum gravity in which the quantum mechanical structures that are traditionally fixed, such as the Fubini–Study metric in the Hilbert space of states, become dynamical and so implement the idea of gravitizing the quantum. In particular, in this formulation of quantum gravity the quantum geometry is still consistent with the principles of unitarity and also captures fundamental aspects of (quantum) gravity, such as topology change. As a result, we address specific ways of testing this new approach to quantum gravity by utilizing multipath interference and optical lattice atomic clocks.

Quantum gravity↗

DOE OSTI2013

Assessment of Offshore Wind Farm Effects on Sea Surface, Subsurface and Airborne Electronic Systems (Final Report)

Offshore wind energy is a valuable resource that can provide a significant boost to the US renewable energy portfolio. A current constraint to the development of offshore wind farms is the potential for interference to be caused by large wind farms on existing electronic and acoustical equipment such as radar and sonar systems for surveillance, navigation and communications. The US Department of Energy funded this study as an objective assessment of possible interference to various types of equipment operating in the marine environment where offshore wind farms could be installed. The objective of this project was to conduct a baseline evaluation of electromagnetic and acoustical challenges to sea surface, subsurface and airborne electronic systems presented by offshore wind farms. To accomplish this goal, the following tasks were carried out: (1) survey electronic systems that can potentially be impacted by large offshore wind farms, and identify impact assessment studies and research and development activities both within and outside the US, (2) engage key stakeholders to identify their possible concerns and operating requirements, (3) conduct first-principle modeling on the interactions of electromagnetic signals with, and the radiation of underwater acoustic signals from, offshore wind farms to evaluate the effect of such interactions on electronic systems, and (4) provide impact assessments, recommend mitigation methods, prioritize future research directions, and disseminate project findings. This report provides a detailed description of the methodologies used to carry out the study, key findings of the study, and a list of recommendations derived based the findings.

17 WIND ENERGY↗

DOE OSTI2016

Neutron Scattering of Residual Hydrogen in 1,4-Dioxane-D8 Liquid. Understanding Measurements with Molecular Dynamics Simulations

That incoherent scattering from protiated molecular liquids adds a constant background to the measured scattering intensity is well known, but less appreciated is the fact that coherent scattering is also induced by the presence of hydrogen in a deuterated liquid. In fact, the scattering intensity can be very sensitive, in the small-q region, with respect to the amounts and distribution of residual H in the system. We used 1,4-dioxane liquid to demonstrate that the partial structure factors of the HD and DD atom pairs contribute significantly to inter-molecular scattering and that uncertainty in the extent of deuteration account for discrepancies between simulations and measurements. Both contributions to uncertainty have similar magnitudes: scattering interference of the hydrogen-deuterium pair, and complementary interference from the deuterium-deuterium pair by virtue of chemical inhomogeneity. This situation arises in practice since deuteration of liquids is often 99% or less. A combined experimental and extensive computational study of static thermal neutron scattering of 1,4-dioxane demonstrates the foregoing. We show, through simulations, that the reason for the differences is the content of protiated dioxane (vendors quote 1%). We estimate that up to 5% (at 298K and at 343K) protiated mole fraction may be involved in generating the scattering differences. Finally, we find that the particular distribution of hydrogen in the protiated molecules affects the results significantly; here we considered molecules to be either fully protiated or fully deuterated. This scenario best reconciles the computational and experimental results, and leads us to speculate that the deuteration synthesis process tends to leave a molecule either fully deuterated or fully protiated. Although we have used 1,4-dioxane as a model liquid, the effects described in this study extend to similar liquids and similar systematic experimental/computational studies can be performed to either understand measurements or calibrate/validate molecular dynamics models.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2014

Nanoparticle-Mediated Systemic Delivery of siRNA for Treatment of Cancers and Viral Infections

RNA interference (RNAi) is an endogenous post-transcriptional gene regulatory mechanism, where non-coding, double-stranded RNA molecules interfere with the expression of certain genes in order to silence it. Since its discovery, this phenomenon has evolved as powerful technology to diagnose and treat diseases at cellular and molecular levels. With a lot of attention, short interfering RNA (siRNA) therapeutics has brought a great hope for treatment of various undruggable diseases, including genetic diseases, cancer, and resistant viral infections. However, the challenge of their systemic delivery and on how they are integrated to exhibit the desired properties and functions remains a key bottleneck for realizing its full potential. Nanoparticles are currently well known to exhibit a number of unique properties that could be strategically tailored into new advanced siRNA delivery systems. This review summarizes the various nanoparticulate systems developed so far in the literature for systemic delivery of siRNA, which include silica and silicon-based nanoparticles, metal and metal oxides nanoparticles, carbon nanotubes, graphene, dendrimers, polymers, cyclodextrins, lipids, hydrogels, and semiconductor nanocrystals. Challenges and barriers to the delivery of siRNA and the role of different nanoparticles to surmount these challenges are also included in the review.

59 BASIC BIOLOGICAL SCIENCES↗

DOE OSTI2014

Design, Implementation, and Evaluation of a Hybrid DS/FFH Spread-Spectrum Radio Transceiver

In recent years there has been great interest in using hybrid spread-spectrum (HSS) techniques for commercial applications, particularly in the Smart Grid, in addition to their inherent uses in military communications. This is because HSS can accommodate high data rates with high link integrity, even in the presence of significant multipath effects and interfering signals. A highly useful form of this transmission technique for many types of command, control, and sensing applications is the specific code-related combination of standard direct-sequence modulation with "fast" frequency-hopping, denoted hybrid DS/FFH, wherein multiple frequency hops occur within a single data-bit time. In this paper, we present the efforts carried out at Oak Ridge National Laboratory toward exploring the design, implementation, and evaluation of a hybrid DS/FFH spread-spectrum radio transceiver using a single Field Programmable Gate Array (FPGA). The FPGA allows the various subsystems to quickly communicate with each other and thereby maintain tight synchronization. We also investigate various hopping sequences against robustness to interference and jamming. Experimental results are presented that show the receiver sensitivity, radio data-rate/bit-error evaluations, and jamming and interference rejection capabilities of the implemented hybrid DS/FFH spread-spectrum system under widely varying design parameters.

data rate↗

DOE OSTI2019

New Technique Sees Bacterial Growth Quicker

Researchers at Pacific Northwest National Laboratory have developed a patent-pending technique for faster and improved way to count bacteria and measure their growth, without killing the sample, by using a white light interferometer. This innovation is available for licensing. For more information, contact Commercialization Manager Jennifer Lee at jennifer.lee@pnnl.gov WLIs are microscopes that split a beam of light and then look for characteristic wavy patterns that appear in images as the two halves of the light ‘interfere’ with each other when recombined. The interference patterns translate into a measurement of different heights or textures on the surface of what’s being viewed and can track it as it changes. Using this previously unexplored approach, researchers were able to quickly see, in great detail, barely perceptible changes in heights down to three nanometers – more than 10,000 times smaller than the diameter of a human hair - in the topography of a sample. Being able to see very detailed height changes is important for bacterial colonies which, the team observed, grow slowly upward as well as out.

47 OTHER INSTRUMENTATION↗

DOE OSTI2015

Electrically-cooled HPGe detector for advanced x-ray spectroscopy and imaging

High Purity Germanium (HPGe) detectors are used for high-resolution x- and gamma-ray spectroscopy. For their operation, the necessary cryogenic cooling is performed with liquid nitrogen or with electromechanical coolers. Although mature and industrialized solutions, most of HPGe detectors integrating electrical coolers present a limited spectroscopic performance due to the generated mechanical vibration and electromagnetic interference. This paper describes a novel HPGe detector, specifically designed to address the challenges of ultimate x-ray spectroscopy and imaging applications. Due to the stringent demands associated with nano-scale imaging in synchrotron applications, a custom-designed cryostat was built around a Canberra CP5-Plus electrical cooler featuring extremely low vibration levels and high cooling power. The heat generated by the cryo-cooler itself, as well as the electronics, is evacuated via an original liquid cooling circuit. This architecture can also be used to address high ambient temperature, which does not allow conventional cryo-coolers to work properly. The multichannel detector head can consist of a segmented monolithic HPGe sensor, or several closely packed sensors. Each sensor channel is read out by state-of-the-art pulse-reset preamplifiers in order to achieve excellent energy resolution for count rates in excess of 1 Mcps. The sensitive electronics are located in EMI-proof housings to avoid any interference from other devices on a beam-line. The front-end of the detector is built using selected high-purity materials and alloys to avoid any fluorescence effects. We present a detailed description of the detector design and we report on its performance. A discussion is also given on the use of electrically cooled HPGe detectors for applications requiring ultimate energy resolution, such as synchrotron, medicine or nuclear industry. (authors)

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2015

A harmonic pulse testing method for leakage detection in deep subsurface storage formations

Abstract Detection of leakage in deep geologic storage formations (e.g., carbon sequestration sites) is a challenging problem. This study investigates an easy‐to‐implement frequency domain leakage detection technology based on harmonic pulse testing (HPT). Unlike conventional constant‐rate pressure interference tests, HPT stimulates a reservoir using periodic injection rates. The fundamental principle underlying HPT‐based leakage detection is that leakage modifies a storage system's frequency response function, thus providing clues of system malfunction. During operations, routine HPTs can be conducted at multiple pulsing frequencies to obtain experimental frequency response functions, using which the possible time‐lapse changes are examined. In this work, a set of analytical frequency response solutions is derived for predicting system responses with and without leaks for single‐phase flow systems. Sensitivity studies show that HPT can effectively reveal the presence of leaks. A search procedure is then prescribed for locating the actual leaks using amplitude and phase information obtained from HPT, and the resulting optimization problem is solved using the genetic algorithm. For multiphase flows, the applicability of HPT‐based leakage detection procedure is exemplified numerically using a carbon sequestration problem. Results show that the detection procedure is applicable if the average reservoir conditions in the testing zone stay relatively constant during the tests, which is a working assumption under many other interpretation methods for pressure interference tests. HPT is a cost‐effective tool that only requires periodic modification of the nominal injection rate. Thus it can be incorporated into existing monitoring plans with little additional investment.

Sun, Alexander Y.↗

DOE OSTI2014

Lubricant-Infused Nanoparticulate Coatings Assembled by Layer-by-Layer Deposition

Omniphobic coatings are designed to repel a wide range of liquids without leaving stains on the surface. A practical coating should exhibit stable repellency, show no interference with color or transparency of the underlying substrate and, ideally, be deposited in a simple process on arbitrarily shaped surfaces. We use layer-by-layer (LbL) deposition of negatively charged silica nanoparticles and positively charged polyelectrolytes to create nanoscale surface structures that are further surface-functionalized with fluorinated silanes and infiltrated with fluorinated oil, forming a smooth, highly repellent coating on surfaces of different materials and shapes. We show that four or more LbL cycles introduce sufficient surface roughness to effectively immobilize the lubricant into the nanoporous coating and provide a stable liquid interface that repels water, low-surface-tension liquids and complex fluids. The absence of hierarchical structures and the small size of the silica nanoparticles enables complete transparency of the coating, with light transmittance exceeding that of normal glass. The coating is mechanically robust, maintains its repellency after exposure to continuous flow for several days and prevents adsorption of streptavidin as a model protein. The LbL process is conceptually simple, of low cost, environmentally benign, scalable, automatable and therefore may present an efficient synthetic route to non-fouling materials.

Sunny, S↗

DOE OSTI2018

Computational Chemistry-Guided Design of Selective Chemoresponsive Liquid Crystals Using Pyridine and Pyrimidine Functional Groups

Computational chemistry-guided designs of chemoresponsive liquid crystals (LCs) with pyridine or pyrimidine groups that bind to metal-cation-functionalized surfaces to provide improved selective responses to targeted vapor species (dimethylmethylphosphonate (DMMP)) over nontargeted species (water) are reported. The LC designs against experiments are tested by synthesizing 4-(4-pentyl-phenyl)-pyridine and 5-(4-pentyl-phenyl)-pyrimidine and quantifying LC responses to DMMP and water. Consistent with the computations, pyridine-containing LCs bind to metal-cation-functionalized surfaces too strongly to permit a response to either DMMP or water whereas pyrimidine-containing LCs undergo a surface-driven orientational transition in response to DMMP without interference from water. The computation predictions are not strongly dependent on assumptions regarding the degree of coordination of the metal ions but are limited in their ability to predict LC responses when using cations with mostly empty d orbitals. Overall, this work identifies a promising new class of chemoresponsive LCs based on pyrimidine that exhibits enhanced tolerance to water, a result that is important because water is a ubiquitous and particularly challenging chemical interferent in chemical sensing strategies based on LCs. The work also provides further evidence of the transformative utility of computational chemistry methods to design LC materials that exhibit selective orientational responses in specific chemical environments.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2020

Silica Nanodepletors: Targeting and Clearing Alzheimer's beta-Amyloid Plaques

Abnormal accumulation of beta-amyloid (A beta) peptide aggregates in the brain is a major hallmark of Alzheimer's disease (AD). A beta aggregates interfere with neuronal communications, ultimately causing neuronal damage and brain atrophy. Much effort has been made to develop AD treatments that suppress A beta aggregate formation, thereby attenuating A beta-induced neurotoxicity. Here, the design of A beta nanodepletors consisting of ultralarge mesoporous silica nanostructures and anti-A beta single-chain variable fragments, with the goal of targeting and eliminating aggregative A beta monomers, is reported. The A beta nanodepletors impart a notable decline in A beta aggregate formation, resulting in significant mitigation of A beta-induced neurotoxicity in vitro. Furthermore, stereotaxic injections of A beta nanodepletors into the brain of an AD mouse model system successfully suppress A beta plaque formation in vivo up to approximate to 30%, suggesting that A beta nanodepletors can serve as a promising antiamylodoisis material.

Jung, Huijin↗

DOE OSTI2018

A Voltammetric Sensor Based on MgFe2O4 Decorated on Reduced Graphene Oxide-modified Electrode for Sensitive and Simultaneous Determination of Catechol and Hydroquinone

In this work facile one step synthesis of magnesium ferrite (MgFe2O4) nanoparticles decorated on reduced graphene oxide (MgFe@RGO) using a microwave assisted hydrothermal procedure is reported. The synthesized material was characterized with help of several techniques and applied for the modification of glassy carbon electrode. Such prepared electrode was utilized for successive simultaneous detection of structurally similar compounds, 1,2- and 1,4-dihydroxibenzenes (catechol (CC) and hydroquinone (HQ)), using differential pulse voltammetry technique. It was found that oxidation current increases linearly with the concentrations of both investigated compounds. Detection limits for both species are ≤0.31 μM. The best analytical response in the presence of both CC and HQ, taking into account peak shape and peak current, was obtained at pH 5.6 utilizing acetate buffer solution. The often-presented species in the surface waters as well as gallic acid and caffeine do not interfere with determination of CC and HQ, while ascorbic acid shows high interference. The method is successfully applied for detection of catechol and hydroquinone in real samples analyses. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2020

Impact of moderate pump–Stokes chirp on femtosecond coherent anti-Stokes Raman scattering spectra

The effects of inducing moderate chirp in the pump and Stokes beams in chirped-probe-pulse femtosecond coherent anti-Stokes Raman scattering (CARS) spectroscopy are discussed. This is an important issue for measurements in high-pressure systems where the CARS beams must be transmitted through glass of significant thickness to reach the probe volume of interest. The effects were investigated both experimentally, by inserting disks of SF-11 glass into the pump and Stokes beam paths, and theoretically, by incorporating pulse chirp into our time-dependent density matrix (TDDM) simulations. Experimentally, we found that inducing moderate pump and Stokes chirp produced significant spectral narrowing of the nonresonant four-wave mixing contribution to the CARS signal, and this allowed us to control the resonant excitation bandwidth to eliminate interferences from neighboring species. The temperature measurement accuracy and precision were essentially unchanged with respect to the unchirped pump and Stokes case. The effect of moderate pump and Stokes chirp on the narrowing of the Raman excitation efficiency envelope was investigated by solving the full set of TDDM through direct numerical integration. The numerical efficiency of the solutions was enhanced dramatically by developing a parallel version of the TDDM code. The calculated Raman excitation efficiency profile was incorporated in our phenomenological spectral fitting codes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2019

Data Trend Shifts Induced by Method of Concentration for Trace Metals in Seawater: Automated Online Preconcentration vs Borohydride Reductive Coprecipitation of Nearshore Seawater Samples for Analysis of Ni, Cu, Zn, Cd, and Pb via ICP-MS

This research compares performance, reproducibility, and detection limits of ambient seawater analysis for trace metals using both borohydride reductive co-precipitation and an automated chelation column (seaFAST™ 2) co-preconcentration for matrix interferent elimination on total and dissolved grab samples in nearshore to marine waters, over a broad concentration range, prior to ICP-MS injection. A move to an online preconcentration method both minimizes sample preparation, and eliminates correction errors when accounting for trace impurities in precipitated samples, induced via reagents. The reproducability of the online preconcentration method described, coupled with low blanks and method detection limits (MDLs), demonstrates an effective move to an automated procedure using ethylenediaminetriacetic and iminodiacetate acid chelation exchange resin and multi-analyte determination via ICP-MS for total and dissolved Ni, Cu, Zn, Cd, and Pb in marine water samples. Average CASS-5 recoveries using the online preconcentration method (n=9) were 109±7%, 104±5%, 103±7%, 101±3%, and 86±8% respectively. The MDLs obtained from the automated method for Ni, Cu, Zn, Cd and Pb were 3.3, 1.8, 13.5, 4, and 10 times lower, respectively, than for the Borohydride method. There were statistically significant differences between the methods for CASS-5 recoveries of Ni, Cu, Zn (p < 0.0001), and Pb (p = 0.0024). Comparison of methods gave high concordance (rC = 0.90) between methods for total and dissolved Ni, Cu, Zn, and Pb, and total Cd.

seaFAST, borohydride, seawater, Ethylenediaminetet↗

DOE OSTI2023

Surface analysis insight note: X‐ray photoelectron spectroscopy analysis of battery electrodes—Challenges with nickel–manganese–cobalt and Li examples using an Al Kα x‐ray source

X‐ray photoelectron spectroscopy (XPS) has become a highly important tool for the analysis of battery materials and components. However, both anecdotal and detailed analysis of selected parts of the literature indicate that many reports of XPS on battery electrodes have significant analysis or data flaws. In this paper, we highlight several of the common challenges that analysts face when using XPS for battery materials, pointing to recent literature that addresses many of the critical issues associated with sample preparation as well as data collection and analysis. A common error for battery materials (and other materials) involves ignoring peak overlaps and interferences. Specifically, when a “minor” peak associated with a component in relatively high concentration overlaps or contributes to the primary peak (or one recommended for quantitative analysis) from a different element in the material. Overlap issues apply to many battery electrodes composed of many elements with complex photoelectron peak structures, as well as those involving peaks with seemingly simpler spectral envelopes such as Li and F. Examples of issues associated with battery systems are highlighted by a discussion of challenges associated with XPS analysis of Li and nickel–manganese–cobalt (NMC) electrodes in battery systems. Lithium analysis has challenges associated with the preparation and an often‐unrecognized peak overlap with F. In our laboratory and in the literature, NMC electrodes are often examined and new XPS users do not always recognize interference of the Auger signal from F KLL (in or on the electrode) with Ni 2p photoelectron spectrum when generated with Al Kα X‐rays. The use of simulated spectra involving both F and NiO demonstrates the extent of F Auger contributions to the Ni 2p signal strength as a function of the F/Ni atom ratio in the material and suggests spectra information that can be used to identify how significant effects will be on the resultant spectra. Our analysis demonstrates that in many cases overlap issues are significant for real electrode materials.

25 ENERGY STORAGE↗

DOE OSTI2026

Ultrabroadband Spacetime Nanoscopy of Terahertz Polaritons in a van der Waals Cavity

Guiding, storing, and processing light at the nanoscale hinges on understanding how polaritons — hybrid quasiparticles of light and matter — propagate and interfere in both space and time. This work introduces a synchrotron-based technique, SYnchrotron SpaceTimE Mapping (SYSTEM), which captures real-time evolution of polariton wave packets with ∼10 nm spatial and sub-100 fs temporal resolution across an ultrabroadband 5–50 THz range. Here, SYSTEM directly visualizes the creation, interference, and decay of multiple high-quality Fabry-Pérot phonon polariton cavity modes in an α-MoO 3 microcavity. These real-space, real-time observations reveal wave-packet dynamics and cavity resonances with record-high quality factors (Q ≈ 100) in the single-digit terahertz regime near 9 THz. SYSTEM thus offers a powerful and broadly applicable platform for probing and engineering ultraslow, deeply subwavelength polaritons, opening new avenues for tailoring light–matter interactions and advancing next-generation THz nanophotonic technologies.

36 MATERIALS SCIENCE↗

DOE OSTI2021

The Bactrian effect: multiple resonances and light Dirac dark matter

The possibility of light dark matter (DM) annihilating through a dark photon (DP) which kinetically mixes (KM) with the Standard Model (SM) hypercharge field is a very attractive scenario. For DM in the interesting mass range below ~1 GeV, it is well known that bounds from the CMB provide a very strong model building constraint forcing the DM annihilation cross section to be roughly 3 orders of magnitude below that needed to reproduce the observed relic density. Under most circumstances this removes the possibility of an s-wave annihilation process for DM in this mass range as would be the case, e.g., if the DM were a Dirac fermion. In an extra-dimensional setup explored previously, it was found that the s-channel exchange of multiple gauge bosons could simultaneously encompass a suppressed annihilation cross section during the CMB era while also producing a sufficiently large annihilation rate during freeze-out to recover the DM relic density. In this paper, we analyze more globally the necessary requirements for this mechanism to work successfully and then realize them within the context of a simple model with two ‘dark’ gauge bosons having masses of a similar magnitude and whose contributions to the annihilation amplitude destructively interfere. We show that if the DM mass threshold lies appropriately in the saddle region of this destructive interference between the two resonance humps it then becomes possible to satisfy these requirements simultaneously provided several ancillary conditions are met. The multiple constraints on the parameter space of this setup are then explored in detail to identify the phenomenologically successful regions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗