Sources of error in glucose determinations in neonatal blood by glucose oxidase methods, including Dextrostix

An investigation was carried out to examine why a glucose oxidase-peroxidase-orthodianisidine method for plasma glucose, without protein precipitation, gave low results for neonatal blood. The magnitude of the difference between the results with and without protein precipitation was examined in a clinical neonatal series, and in sera to which bilirubin, hemolysate, pure hemoglobin, and uric acid had been added. Systematic linear inhibition was demonstrated with bilirubin, and the results suggested that high concentrations of hemolysate and uric acid could also interfere. Use of alkaline protein precipitants eliminated the inhibition. Dextrostix test results for neonatal blood are compared with results of conventional glucose analyses and possible sources of discrepancy examined.     

Temperature-stable low-loss microwave filters using dielectric resonators

Recently developed high-permittivity low-loss temperature-stable dielectric materials have been used as resonators in microwave filters. The resulting low-loss filters possess extremely good temperature stability. Proper design and the use of metal-screw mode suppressors have eliminated the further problem in dielectric-resonator filters of spurious modes just above the passband.     

Deposition method,relative humidity,and surface property effects of bacterial spore reaerosolization via pulsed air jet

Biological warfare incidents generate both immediate and delayed hazards, potentially resulting from reaerosolization of deposited hazardous particles from surfaces. Understanding the causes and effects of the initial deposition method and environmental conditions on reaerosolization is important in hazard prediction and selection of mitigation approaches. This study was conducted to determine the amount of reaerosolization of various bacterial spores and 1 µm polystyrene latex microspheres deposited wet or dry and incubated at 20 or 80% relative humidity (RH). The organisms used in this study were Bacillus atrophaeus var. globigii (Bg), B. thuringiensis (Bt), B. anthracis ΔSterne (Ba-ΔSterne), Ba-ΔSterne ΔbclA mutant (BclA), and Ba-ΔSterne ΔcotE mutant (CotE). These organisms represent a range of spore types with different outer surfaces: spores with exosporium hairs and a basal layer (Ba-ΔSterne and Bt), spores with a basal layer (BclA), and spores with a spore coat only (no exosporium, Bg and CotE). A pulsed air impinging jet was used to reaerosolize particles from gridded glass surfaces. The amount of reaerosolization was determined by counting the number of particles on the gridded surface before and after applying the air jet. Results indicate that, in general, higher reaerosolization was observed when particles were deposited dry and incubated at lower RH conditions. Our results indicate that Bt (has exosporium) was reaerosolized more readily than Bg (no exosporium) in all cases studied. This method can be used in laboratory studies to compare bacterial spore behavior and to study the relative effects of different spore outer layers and surface types on reaerosolization.

© 2017 Leidos, Inc.     

Process flow sheet synthesis: Systems‐level design applied to synthetic crude production

A novel approach for conceptual design for process flow sheets at the “systems‐level” is showcased in this article. A graphical technique, called the “GH‐space,” is used to analyze the flows of material, heat and work within a process to provide insight into the interactions of various units within the process. Any unit process, which interacts with the surroundings by transferring heat and work, can be represented as a vector on the GH‐space. While material and energy balances are normally performed on a flowsheet, this vectored approach allows the material and energy balances to be used to construct a flowsheet. This article focuses on using the GH‐space to synthesis a synthetic fuels flowsheet. It was shown that a process could be designed that not only produced the desired product but could also consume carbon dioxide as a feed, along with the feeds of methane and oxygen, and could even potentially generate electricity. © 2017 American Institute of Chemical Engineers AIChE J, 63: 5413–5424, 2017     

Linear stability analysis of a two-fluid model for air-water bubble columns

Linear stability analysis is performed for the two-dimensional, two-fluid model for gas-liquid flow applied in our previous computational study of bubble columns [Monahan, S.M., Vitankar, V.S., Fox, R.O., 2005. CFD predictions for flow-regime transitions in bubble columns. A.I.Ch.E. Journal 51, 1897-1923]. The growth rate and the velocity of propagation for a small-amplitude disturbance wave are shown to be highly dependent on the wave number, the direction of propagation, and the two-fluid model parameters. Two types of vertical instabilities are identified: one corresponding to the classical analysis of Jackson [1963. The mechanics of fluidized beds. I: the stability of the state of uniform fluidization. Transactions of the Institution of Chemical Engineers 41, 13-21] for the one-dimensional model, and the other due to a second pair of roots to the characteristic equation of the linearized two-dimensional model. Numerical simulations keeping one type or the other of the roots stable (or unstable) show distinctly different dynamics and suggest that large-scale instabilities seen experimentally may be associated with the second type of instability. The latter leads to instability in the horizontal velocities and is associated with a positive lift coefficient in flows without mean shear in the presence of isotropic bubble-bubble interactions (i.e., “bubble pressure”). This instability is thus different than previously reported instabilities due to negative lift or cooperative/hindered rise.     

Fischer-Tropsch reactor selection

A comparison of slurry versus fixed-bed reactor design principles for methanol and Fischer-Tropsch distillate production.Notation a gas-liquid interfacial area, m^–1 - CCat catalyst concentration, kg mole/m³ - C _HG hydrogen concentration in gas phase, kg mole/m³ - C ^* _HL hydrogen concentration, liquid, in equilibrium with gas, kg mole/m³ - C _HL hydrogen concentration in the liquid phase, kg mole/m³ - D I.D. of reactor, m - GHSV Gas hourly space velocity, Nm³ (H₂ + CO)/[h · m³ reactor volume], (reactor volume is expanded slurry height times cross section area) - H solubility coefficient of hydrogen =C _HG/C ^* C _HL - l Inlet ratio of CO/H₂ - k _L liquid side mass transfer coefficient, m/s - k _H effective reaction rate constant for hydrogen consumption, s^–1 (note that to agree with space velocity in Nm³/[s · kgCat],k _H =k _H ·CCat wherek _H is in m³/[kg · s] - L Length of expanded slurry bed, m - P pressure, kPa - r rate of hydrogen consumption,r =k _H ·C _HL, kg moles/[m³ · s] - SV Space velocity in actual m³ inlet gas/[s · m³] - T temperature, K - U Usage ratio of CO/H₂ - X _H hydrogen fractional conversion per pass (IfU=l,X _H =X _CO) - contraction factor, = [m³/s(X _{H 2+CO} = 1)-m³/s(inlet)]/[m³/s(inlet)] - * contraction factor modified for H₂ conversion, * = · (1 +U)/(1 +l) - _L fractional liquid hold-up     

Clinical delivery of therapeutic agents based on metals

Metals have been used in clinical practice for hundreds of years and for a variety of indications. Although potent agents whose activity may be adapted by manipulation of their chemistry and that of associated ligands, their use has been limited by toxic effects. There is now a burgeoning series of delivery technologies available which may be adapted to the administration of metal based drugs. Together with greater understanding of metal chemistry and their mechanisms of action in disease processes, there is an opportunity to increase the use of metals in medicine by targeting their action more effectively to the therapeutic site and/or protecting the body from toxic effects.     

A Review on Piezoelectric,Magnetostrictive, and Magnetoelectric Materials and Device Technologies for Energy Harvesting Applications

In the coming era of the internet of things (IoT), wireless sensor networks that monitor, detect, and gather data will play a crucial role in advancements in public safety, human healthcare, industrial automation, and energy management. Batteries are currently the power source of choice for operating wireless network devices due to their ease of installation; however, they require periodic replacement due to capacity limitations. Within the scope of the IoT, battery maintenance of the trillion sensor nodes that may be implemented will be practically infeasible from environmental, resource, and labor cost perspectives. In considering individual self‐powered sensor nodes, the idea of harvesting energy from ambient vibrations, heat, and electromagnetic waves has recently triggered noticeable research interest in the academic community. This paper gives an overview of energy harvesting materials and systems. Three main categories are presented: piezoelectric ceramics/polymers, magnetostrictive alloys, and magnetoelectric (ME) multiferroic composites. State‐of‐the‐art harvesting materials and structures are presented with a focus on characterization, fabrication, modeling and simulation, and durability and reliability. Some perspectives and challenges for the future development of energy harvesting materials are also highlighted.