Effect of ionizing radiation on a series of saturated polyesters
Effect of ionizing radiation on series of saturated polyesters
SATURATION↗
SEARCH · Engineering Papers
Results for “SATURATION”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Saturation behavior of a Doppler broadened transition involving levels with closely spaced structure
Saturation behavior of Doppler broadened transition involving levels with closely spaced structure
DOPPLER EFFECT↗
Optimal control of saturating systems with stochastic inputs
Optimal control of nonlinear saturating systems with stochastic inputs
NONLINEAR SYSTEM↗
Measurement of saturation induced optical nonreciprocity in a ring laser plasma.
Saturation induced optical nonreciprocity in He-Ne ring laser plasma, eliminating frequency locking by using Faraday effect
GAS LASER↗
Design and development of a high power, low saturation voltage silicon switching transistor Quarterly report
Silicon switching transistor with saturation voltage of 0.1 V at 75 A collector current
SATURATION↗
Propellant saturation test, 2 February - 3 May 1966
The objective of this test program was to determine the behavior of gas-saturated water and nitrogen tetroxide under various flow and pressure drop conditions. A second part of the test program is to be conducted at a later time to determine the rate of gas diffusion into propellants. The test program was conducted by the Fluid Systems Test Section of the Thermochemical Test Branch for the Auxiliary Propulsion and Pyrotechnics Branch, Propulsion and Power Division. Testing was accomplished at the Fluid Systems Test Facility during the period from February 2, 1966, to May 3, 1966.
Nitrogen compound↗
Improved Saturation Performance in High Speed Waveguide Photodetectors at 1.3 ??sing an Asymmetric InA1GaAs/InGaAsP Structure
Waveguide photodetector (WGPD) results have recently been presented demonstrating the very large bandwidth-efficiency product potential of these devices. Improved saturation and linearity characteristics are realized in waveguide p-i-n photodetectors at 1.3 ??y using an asymmetric cladding structure with InA1GaAs/InGaAsP in the anode and InGaAsP in the cathode.
multi-mode structures photocurrent saturation wave↗
Saturated Monoglyceride Polymorphism and Gel Formation of Biodiesel Blends
Crystallization or gel formation of normal paraffins in diesel fuel under cold weather conditions leading to fuel filter clogging is a common problem. Cold weather operability of biodiesel (B100) and blends with diesel fuel presents additional complexity because of the presence of saturated monoglycerides (SMGs) and other relatively polar species. Currently, the cloud point measurement (a measure of when the first component crystallizes out of solution) is used to define the lowest temperature at which the fuel can be used without causing cold weather issues. While filter plugging issues have declined, there still remain intermittent unexpected problems above the cloud point for biodiesel blends. Development of a fundamental understanding of how minor components in biodiesel crystallize, gel, and transform is needed in order to prevent these unexpected issues. We have found that SMGs, a low level impurity present in B100 from the production process, can crystallize out of solution and undergo a solvent-mediated polymorphic phase transformation to a more stable, less soluble form. This causes them to persist at temperatures above the cloud point once they have some out of solution. Additionally, we have found that SMGs can cause other more soluble, lower melting point minor components in the B100 to co-crystallize and come out of solution. Monoolein, another minor component from the production process is an unsaturated monoglyceride with a much lower melting point and higher solubility than SMGs. It is able to form a co-crystal with the SMGs and is found together with the SMGs on plugged filters we have analyzed in our laboratory. An observation of isolated crystals in the lab led us to believe that the SMGs may also be forming a gel-like network with components of the B100 and diesel fuel. During filtration experiments, we have noted that in some cases a solid layer of crystals forms and blocks the filter completely, while in other cases this does not occur. Because SMGs are polar and can form layered networks once a sufficient amount of crystals have come out of solution, we recently began investigating the ability of SMGs to form a gel network with fuel components as well as with other minor polar components in the fuel in order to obtain a fundamental understanding of the mechanism of formation. It has been well established that this type of phenomena occurs in sub-sea pipelines where a chief crystallizing component begins to crystallize out of solution. Once a sufficient amount of crystals exists, a volume spanning network of solid crystals can trap liquid crude oil and form a solid-like gel network. We are investigating whether this type of phenomena can occur with SMGs and both fatty acid methyl esters from the B100 and normal paraffins from diesel fuel. Additionally, SMGs are well known to incorporate water into their layered crystal structure. Water is often used to stabilize less stable polymorphic forms of SMGs, therefore water was another minor component of interest. Also of interest is glycerin which has been found on clogged filters in our laboratory.
30 DIRECT ENERGY CONVERSION↗
Anomalous solute transport in saturated porous media: Relating transport model parameters to electrical and nuclear magnetic resonance properties
Abstract The advection‐dispersion equation (ADE) fails to describe commonly observed non‐Fickian solute transport in saturated porous media, necessitating the use of other models such as the dual‐domain mass‐transfer (DDMT) model. DDMT model parameters are commonly calibrated via curve fitting, providing little insight into the relation between effective parameters and physical properties of the medium. There is a clear need for material characterization techniques that can provide insight into the geometry and connectedness of pore spaces related to transport model parameters. Here, we consider proton nuclear magnetic resonance (NMR), direct‐current (DC) resistivity, and complex conductivity (CC) measurements for this purpose, and assess these methods using glass beads as a control and two different samples of the zeolite clinoptilolite, a material that demonstrates non‐Fickian transport due to intragranular porosity. We estimate DDMT parameters via calibration of a transport model to column‐scale solute tracer tests, and compare NMR, DC resistivity, CC results, which reveal that grain size alone does not control transport properties and measured geophysical parameters; rather, volume and arrangement of the pore space play important roles. NMR cannot provide estimates of more‐mobile and less‐mobile pore volumes in the absence of tracer tests because these estimates depend critically on the selection of a material‐dependent and flow‐dependent cutoff time. Increased electrical connectedness from DC resistivity measurements are associated with greater mobile pore space determined from transport model calibration. CC was hypothesized to be related to length scales of mass transfer, but the CC response is unrelated to DDMT.
Swanson, Ryan D.↗
Submarine landslides triggered by destabilization of high-saturation hydrate anomalies: LANDSLIDES CAUSED BY HYDRATE ANOMALIES
Submarine landslides occur along continental margins at depths that often intersect the gas hydrate stability zone, prompting suggestions that slope stability may be affected by perturbations that arise from changes in hydrate stability. Here we develop a numerical model to identify the conditions under which the destabilization of hydrates results in slope failure. Specifically, we focus on high-saturation hydrate anomalies at fine-grained to coarse-grained stratigraphic boundaries that can transmit bridging stresses that decrease the effective stress at sediment contacts and disrupt normal sediment consolidation. We evaluate slope stability before and after hydrate destabilization. Hydrate anomalies act to significantly increase the overall slope stability due to large increases in effective cohesion. However, when hydrate anomalies destabilize there is a loss of cohesion and increase in effective stress that causes the sediment grains to rapidly consolidate and generate pore pressures that can either trigger immediate slope failure or weaken the surrounding sediment until the pore pressure diffuses away. In cases where failure does not occur, the sediment can remain weakened for months. In cases where failure does occur, we quantify landslide dynamics using a rate and state frictional model and find that landslides can display either slow or dynamic (i.e., catastrophic) motion depending on the rate-dependent properties, size of the stress perturbation, and the size of the slip patch relative to a critical nucleation length scale. Our results illustrate the fundamental mechanisms through which the destabilization of gas hydrates can pose a significant geohazard.
58 GEOSCIENCES↗
Surface Protected Organozirconium Catalyzes C─H Alumination of Saturated Hydrocarbons
Surface grafted organozirconium catalyzes C─H/Et─Al exchange reactions, involving saturated hydrocarbons and AlEt 3 , to afford organoaluminum compounds and ethane. The Zr(O t Bu) 3 @SiO 2 -Al 2 O 3 –700 (1) catalyst contains monopodal ≡SiO─Zr(O t Bu) 3 and only a few residual silanols (<5%). Nonetheless, these silanols are the Achille's heel of 1, providing a pathway for surface and catalyst degradation during catalysis, limiting the alkylaluminum yield and catalyst turnover. Support degradation, involving the cleavage of Si─O bonds by activated surface organometallics, is inhibited by capping silanols with ─SiMe 3 . Residual silanols in 1 react with allyltrimethylsilane, as determined by solid-state 13 C and 29 Si nuclear magnetic resonance (NMR) spectroscopy, infrared (IR) spectroscopy, and reaction stoichiometry, to form Zr(O t Bu) 3 /SiMe 3 @SiO 2 -Al 2 O 3–700 (2), which is resistant to degradation by AlEt 3 . C─H alumination of dodecane catalyzed by 2 produces higher yields of the 1-dodecylaluminum product in comparison to 1, and in >95% selectivity. Additionally, methane undergoes 2-catalyzed C─H alumination, providing a route to AlMe 3 .
Banerjee, Sayak [Iowa State Univ., Ames, IA (Unite↗
Anomalous Loss Reduction Below Two‐Level System Saturation in Aluminum Superconducting Resonators
Superconducting resonators are widely used in many applications such as qubit readout for quantum computing, and kinetic inductance detectors. These resonators are susceptible to numerous loss and noise mechanisms, especially the dissipation due to two-level systems (TLS) which become the dominant source of loss in the few-photon and low temperature regime. In this study, capacitively-coupled aluminum half-wavelength coplanar waveguide resonators are investigated. Surprisingly, the loss of the resonators is observed to decrease with a lowering temperature at low excitation powers and temperatures below the TLS saturation. This behavior is attributed to the reduction of the TLS resonant response bandwidth with decreasing temperature and power to below the detuning between the TLS and the resonant photon frequency in a discrete ensemble of TLS. When response bandwidths of TLS are smaller than their detunings from the resonance, the resonant response and thus the loss is reduced. At higher excitation powers, the loss follows a logarithmic power dependence, consistent with predictions from the generalized tunneling model (GTM). A model combining the discrete TLS ensemble with the GTM is proposed and matches the temperature and power dependence of the measured internal loss of the resonator with reasonable parameters.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
The asymptotic form of non-global logarithms, black disc saturation, and gluonic deserts
Here, we develop an asymptotic perturbation theory for the large logarithmic behavior of the non-linear integro-differential equation describing the soft correlations of QCD jet measurements, the Banfi-Marchesini-Smye (BMS) equation. Furthermore, this equation captures the late-time evolution of radiating color dipoles after a hard collision. This allows us to prove that at large values of the control variable (the non-global logarithm, a function of the infra-red energy scales associated with distinct hard jets in an event), the distribution has a gaussian tail. We also compute the decay width analytically, giving a closed form expression, and find it to be jet geometry independent, up to the number of legs of the dipole in the active jet. By enabling the asymptotic expansion we find that the perturbative seed is correct; we perturb around an anzats encoding formally no real emissions, an intuition motivated by the buffer region found in jet dynamics. This must be supplemented with the correct application of the BFKL approximation to the BMS equation in collinear limits. Comparing to the asymptotics of the conformally related evolution equation encountered in small-x physics, the Balitisky-Kovchegov (BK) equation, we find that the asymptotic form of the non-global logarithms directly maps to the black-disc unitarity limit of the BK equation, despite the contrasting physical pictures. Indeed, we recover the equations of saturation physics in the final state dynamics of QCD.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Probing gluon saturation with next-to-leading order photon production at central rapidities in proton-nucleus collisions
Here, we compute the cross section for photons emitted from sea quarks in proton-nucleus collisions at collider energies. The computation is performed within the dilute-dense kinematics of the Color Glass Condensate (CGC) effective field theory. Albeit the result obtained is formally at next-to-leading order in the CGC power counting, it provides the dominant contribution for central rapidities. We observe that the inclusive photon cross section is proportional to all-twist Wilson line correlators in the nucleus. These correlators also appear in quark-pair production; unlike the latter, photon production is insensitive to hadronization uncertainties and therefore more sensitive to multi-parton correlations in the gluon saturation regime of QCD. We demonstrate that k ⊥ and collinear factorized expressions for inclusive photon production are obtained as leading twist approximations to our result. In particular, the collinearly factorized expression is directly sensitive to the nuclear gluon distribution at small x. Other results of interest include the realization of the Low-Burnett-Kroll soft photon theorem in the CGC framework and a comparative study of how the photon amplitude is obtained in Lorenz and light-cone gauges.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Universality in asymptotic bounds and its saturation in 2D CFT
We study asymptotics of three point coefficients (light-light-heavy) and two point correlators in heavy states in unitary, compact 2D CFTs. We prove an upper and lower bound on such quantities using numerically assisted Tauberian techniques. We obtain an optimal upper bound on the spectrum of operators appearing with fixed spin from the OPE of two identical scalars. While all the CFTs obey this bound, rational CFTs come close to saturating it. This mimics the scenario of bounds on asymptotic density of states and thereby pronounces an universal feature in asymptotics of 2D CFTs. Next, we clarify the role of smearing in interpreting the asymptotic results pertaining to considerations of eigenstate thermalization in 2D CFTs. In the context of light-light-heavy three point coefficients, we find that the order one number in the bound is sensitive to how close the light operators are from the $\frac{c}{32}$ threshold. In context of two point correlator in heavy state, we find the presence of an enigmatic regime which separates the AdS 3 thermal physics and the BTZ black hole physics. Furthermore, we present some new numerical results on the behaviour of spherical conformal block.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Regimes of Hydrate Formation in the Process of Injection of Carbon Dioxide into a Porous Medium Saturated with Methane and Water
The problem on the formation of the hydrate of carbon dioxide in the process of its injection into a porous medium saturated with methane and water, whose initial temperature does not correspond to the thermodynamic conditions of existence of the carbon-dioxide hydrate, was considered. This problem was solved for the case where the hydrate formation takes place at the front interface not coincident with the boundary of displacement of methane by carbon dioxide. It is shown that, in the case where the initial temperature of the porous medium exceeds the equilibrium temperature of hydrate formation, the carbon-dioxide hydrate can be formed in three regimes. Curves separating these regimes depending on the injection pressure, the initial temperature of the medium, and its permeability have been constructed.
42 ENGINEERING↗
Accurate Measurement of Gain Saturation of Superconductor–Insulator–Superconductor Mixers with Logarithmic Power Detectors
Correct measurement of the power of a continuous wave signal superimposed on a broadband noise is a presupposition for the accuracy of the gain saturation measurement of a superconductor–insulator–superconductor mixer. In practice, the response of a logarithmic power detector to a mixture of broadband noise and continuous wave signal can be unexpectedly nonlinear. This nonlinearity can cause significant error if correction is not applied.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
The Effect of Hf Substituting for Cu on the Glass-Forming Ability, Crystallization Behavior, and Saturation Magnetization in Fe{sub 85}Si{sub 2}B{sub 8}P{sub 4}Cu{sub 1−x}Hf{sub x} Alloys
The effect of Hf substituting for Cu on the glass-forming ability (GFA), crystallization behavior, and saturation magnetization (M{sub s}) in Fe-rich Fe{sub 85}Si{sub 2}B{sub 8}P{sub 4}Cu{sub 1−x}Hf{sub x} alloys has been investigated. The result shows that the addition of Hf plays a positive role in improving GFA, and the Fe{sub 85}Si{sub 2}B{sub 8}P{sub 4}Cu{sub 0.5}Hf{sub 0.5} alloy ribbon shows an entirely amorphous structure. Both the ribbons of Fe{sub 85}Si{sub 2}B{sub 8}P{sub 4}Cu{sub 1} and Fe{sub 85}Si{sub 2}B{sub 8}P{sub 4}Cu{sub 0.5}Hf{sub 0.5} have two obviously exothermic crystallization peaks, and the addition of Hf improves the onset temperatures of both first and second crystallization peaks, and leads to the improvement of the thermal stability of the amorphous alloys. For the Fe{sub 85}Si{sub 2}B{sub 8}P{sub 4}Cu{sub 0.5}Hf{sub 0.5} ribbon, after annealing at 623 K, crystallization seeds with sizes of 2–4 nm are found and the initial crystallization has occurred; as the annealing temperature is increased to 723 and 823 K, the size distribution of most of the grains is about 20 nm and bigger than 20 nm, respectively. The M{sub s} of the Fe{sub 85}Si{sub 2}B{sub 8}P{sub 4}Cu{sub 0.5}Hf{sub 0.5} ribbon is about 154 emu/g, which is obviously lower than 205 emu/g of the Fe{sub 85}Si{sub 2}B{sub 8}P{sub 4}Cu{sub 1} ribbon. However, after annealing at 723 K, the M{sub s} increases to 212 emu/g for the former alloy. The newly developed amorphous/nanocrystalline Fe-Si-B-P-Cu-Hf alloy with excellent soft magnetic properties shows a potential application for substituting partial Si steels.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗