The Updated Bottom Up Solution Applied to Atmospheric Pressure Photoionization and Electrospray Ionization Mass Spectrometry

The Updated Bottom Up Solution (UBUS) was recently applied to atmospheric pressure chemical ionization (APCI) mass spectrometry (MS) of triacylglycerols (TAG). This report demonstrates that the UBUS applies equally well to atmospheric pressure photoionization (APPI) MS and to electrospray ionization (ESI) MS. Critical Ratio 1 (CR1), the [MH]⁺/Σ[DAG]⁺ or [MNH₄]⁺/Σ[DAG]⁺ ratio, does not exhibit the same strongly sigmoidal shape as it does by APCI‐MS. CR1 varies more widely for APPI‐MS than by APCI‐MS, having a maximum value of 11.8, indicating a much greater effect of unsaturation on ion ratios in APPI‐MS than APCI‐MS. Critical Ratio 2, the [AA]⁺/[AB]⁺ ratio for Type II TAG or [AC]⁺/([AB]⁺+[BC]⁺) ratio for Type III TAG, allows quantification of regioisomers of TAG, and shows good agreement for APPI‐MS to regioisomer quantification determined by APCI‐MS. Critical Ratio 3, the [BC]⁺/[AB]⁺ ratio for Type III TAG, reveals new trends relating the degree of unsaturation by APPI‐MS, and shows that structural assignments made by ESI‐MS are in good agreement to APCI‐MS data. In addition to providing valuable structural information, the Critical Ratios also constitute a reduced data set that allows APPI‐MS or ESI‐MS mass spectra to be reconstructed when processed through the UBUS. Quantification by APPI‐MS of vitamin D in the gelcaps gave values of 42.90 ± 0.83 μg, or 1716 ± 33 international units, in good agreement with APCI‐MS.     

Critical Ratios for structural analysis of triacylglycerols using mass spectrometry

Recent developments have finally allowed fragment behaviors using APCI‐MS to be elucidated after twenty years of literature reports. Critical Ratios have been defined that correspond to various aspects of triacylglycerol (TAG) analysis, from overall degree of unsaturation to localization of fatty acids on the glycerol backbone (regioisomers), to grouping of unsaturated fatty acids. The same ratios also constitute a compact library of TAG mass spectra.     

Wall Smoke Deposition from a Hot Smoke Layer

Smoke deposition from a hot smoke layer onto wall surfaces was studied in a hood apparatus using polymethylmethacrylate, polypropylene, and gasoline as fuels. Based upon prior analysis by Butler and Mulholland, the smoke deposition was expected to be dominated by thermophoresis. The deposited smoke samples were collected on glass filter paper attached to the hood wall and the mass per unit area of smoke deposited was measured gravimetrically. Measurements were made of quantities required for the prediction of thermophoretic smoke deposition. The smoke deposition measured in the experimental program was well predicted by the thermophoretic smoke deposition equation. The thermophoretic smoke deposition equation was found to be suitable for predicting smoke deposition onto wall surfaces exposed to fire environments.     

Re-engineering the tender code for construction works

The UK's NJCC Code of Procedure for Single Stage Selective Tendering (now withdrawn) and its successor, the CIB's Code of Practice for the Selection of Main Contractors are criticized in the light of decisions of the common law courts with regard to regulation of the tendering process. It is argued that a new ‘Tendering Code’ should be produced in the style and format of a contract document which reflects not only the statutory regulation imposed on public bodies, but common law decisions of the courts. The nature of this tendering contract is explained as a means of regulating the tendering process. Issues discussed are: dealing with errors and irregularities found in tenders; dealing with non-compliant tenders; dealing with tender withdrawal prior to its acceptance or rejection; making provisions as to time for submission of tenders and dealing with late tenders; making provision for submission of tender by fax or other electronic means; making provision for evaluation of tenders received; and imposing or negotiating reductions in price with tenderers prior to acceptance. The paper concludes that the common law obligations placed on the owner to treat all tenderers equally and fairly and to apply the tender conditions when evaluating tenders and awarding contracts seems to be good common sense and of commercial advantage, not only to the immediate parties concerned but also to the wider community.     

Modeling Environmental Degradation of SiC‐Based Fibers

Experimental data on grain growth and oxidation kinetics of SiC‐based fibers, as well as the accompanying strength degradation, in argon, air, and moist air are interpreted using a mechanistic model. The grain growth from thermal history is modeled using conventional models, and its influence on strength is modeled assuming that the flaw size scales with grain size. The model for fiber oxidation uses available relevant thermodynamic and kinetic data for reactions, vapor pressures, oxygen permeation, and boundary layer effects to capture scale thickness data reported by several prior works, in static or flowing air, moist air, and steam. The effect of the oxide scale on strength was modeled assuming that the flaw size scaled with scale thickness. The resulting model is compared with experimental data and is shown to capture most of the data in the literature on degradation of HiNicalon^? and HiNicalon^? type S fibers.     

Making Nonwoven Fibrous Poly(ε‐caprolactone) Constructs for Antimicrobial and Tissue Engineering Applications by Pressurized Melt Gyration

A pressurized melt gyration process has been used for the first time to generate poly(ε‐caprolactone) (PCL) fibers. Gyration speed, working pressure, and melt temperature are varied and these parameters influence the fiber diameter and the temperature enabled changing the surface morphology of the fibers. Two types of nonwoven PCL fiber constructs are prepared. First, Ag‐doped PCL is studied for antibacterial activity using Gram‐negative Escherichia coli and Pseudomonas aeruginosa microorganisms. The melt temperature used to make these constructs significantly influences antibacterial activity. Neat PCL nonwoven scaffolds are also prepared and their potential for application in muscular tissue engineering is studied with myoblast cells. Results show significant cell attachment, growth, and proliferation of cells on the scaffolds.

     

A framework for governance of public green spaces in cities

Public authorities that seek to transfer the cost of managing green spaces to the private sector face apprehension about the extent of community input in managing of public green spaces in cities. In practice, the governance arrangements for managing public green spaces are neither a purely private or public sector responsibility. They are part of complex and contested governance schemas that involve multiple stakeholder groups with varying interests and responsibilities. This paper proposes a simple framework to support different modes of governance appropriate for the management of public green spaces in cities. The framework classifies stakeholders’ desires for engagement based on ecosystem service characteristics defined on a spectrum of excludability and rivalry. The framework is applied to case studies in Australia and Canada. Finally, we discuss the new insights for governance arrangements for public green space management in cities.     

Active Sensing for Monitoring the Properties of Solid Rocket Motor Propellant Grains

Aging induced changes in the mechanical properties of solid propellant can lead to defects, such as cracks and grain‐liner separations, that limit the service lifetime of solid rocket motors. The use of embedded sensors is one approach that is being explored by various researchers to augment legacy inspection and prediction methods. We present herein an active sensing technique that is particularly suited for monitoring the properties of solid propellant, as it does not introduce electrical wires into the motor. Based on the use of magnetic induction for excitation and an optical fiber Bragg grating sensor to measure deformation, the method can be used to characterize the properties of a material with which it is in contact. In this paper, we first present proof‐of‐principal experiments demonstrating the utility of the method in characterizing the visco‐elastic properties of an adhesive, and in following changes in viscosity of an epoxy resin during cure. We next apply the method to solid propellant, and present data demonstrating that the method can be used to measure a deflection‐load curve of an aluminized HTPB propellant. In addition, we also show that the observed strain rate sensitivity matches that found in the literature and that the method had more than adequate resolution to observe the expected changes in material properties due to aging.