Epoxy paint failure in B-52 fuel tanks: Part II. Influence of DIEGME concentration in the fuel on the failure process

A model has been proposed to explain the failure of the original BMS10-39 epoxy paint on upper vertical surfaces in B-52 fuel tanks. The model involves interaction of the paint with DIEGME, a fuel system ice inhibitor (FSII) in jet fuel, that is distilled from the liquid fuel. In this communication, distillation experiments used to support the model are refined to better match the mass transfer of vapor from fuel in a B-52 fuel tank at close to room temperature. The interaction of these lower temperature distillates with the paint affirms the earlier model. On the basis of these experiments it is proposed that paint failure may be controlled or eliminated by reducing the level of DIEGME in the fuel. Proposed changes in military jet fuel composition are detailed.     

Induction of tolerance to human gamma-globulin in FcR gamma- and Fc gammaRII-deficient mice

FcR gamma-deficient mice were used to examine the role of Fc gamma receptors in the induction of peripheral tolerance to human gamma-globulin (HGG). FcR gamma-deficient mice injected with HGG in adjuvant demonstrated a CD4+ T cell response to in vitro challenge with HGG, as assayed by proliferation, cytokine secretion, and Ag-specific help for B cell Ab production. In vitro kinetics of Ag-specific proliferation were similar in both conventional and knockout mice. Peripheral tolerance could be established in these mice with a single dose of deaggregated protein, despite the lack of functional Fc gammaRI, the high affinity receptor for monomeric IgG. Establishment of unresponsiveness was observed at both the T and B cell levels. T cell tolerance was manifested in the reduction of T cell helper function and Ag-induced release of Th1- and Th2-like cytokines, as well as decreased proliferation to Ag-specific stimulation. B cell tolerance was demonstrated in knockout and normal mice by failure to detect HGG-specific Ab production using an immunization protocol for Ab production that bypasses the need for Ag-specific T cells. These results demonstrate that induction of tolerance in CD4+ cells to HGG does not require transduction of a signal through Fc gammaRI. Furthermore, the ability to induce tolerance to HGG in B cells in Fc gammaRII-deficient mice suggests that down-regulation of Ag-specific B cells through Fc gammaRII is not the mechanism by which B cell tolerance is induced. However, Fc gammaRII plays a role in regulating the immune response since the Ab response to immunogenic HGG in Fc gammaRII-deficient mice is markedly enhanced.     

NICKEL OXIDE IN GLAZES1

Colors produced from NiO. —The literature on this subject published in the Transactions of the Society is briefly reviewed. Effects of variations of RO in cone 6 glazes on colors from nickel oxide. —Red colors are produced when ZnO and BaO are used in certain proportions. Blues and purples of varied shades and hues are developed with varied combinations of ZnO, CaO and BaO. Grays are possible in presence of CaO and MgO.     

Reliable mixture critical point computation using polynomial homotopy continuation

The numerical computation of multicomponent mixture critical points has been the subject of much study due to their theoretical and practical importance. Both deterministic and stochastic methods have been applied with varying degrees of reliability and robustness. In this work, we utilize numerical polynomial homotopy continuation (NPHC) to reliably identify all mixture critical points. This method is unique due to its robustness, initialization‐free nature and ease of parallelization. For a given system of equations, all complex solutions are found. Computational times are also found to be invariant to mixture composition. We validate this technique against previous work and extend the method to mixtures of up to eight components. NPHC is shown to be a modern and powerful technique which offers mathematical reliability at a moderate computational cost. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4497–4507, 2016     

Epoxy paint failure in B-52 fuel tanks: Part I—Preliminary development of a model for the process

A small percentage of the protective interior topcoat in B-52 integral wing fuel tanks is failing. Two separate modes of failure are observed. On vertical surfaces, fragments of paint detached from the aluminum contain frozen in wrinkles, striations and channels. On the floor of the fuel tank, paint detached from the aluminum is flat and featureless. In this first communication, the BMS10-39 epoxy paint is structurally characterized, with emphasis on the detection of elements of chemical degradation. A preliminary model is then developed for the delamination process operative on vertical surfaces, as supported by interactions of the coating with diethylene glycol monomethyl ether (DIEGME—a fuel system deicer used in military jet fuel) in high temperature distillates from JP-8 jet fuel; and for the delamination process operative on the floor of the fuel cell based on interactions of the paint with mixtures of water and DIEGME.     

A training plan for first year graduate psychology students in a Veterans Administration hospital.

The geographical proximity and working relationship of the University of Utah and the Salt Lake City VA Hospital have facilitated integration of academic and practician phases of the cooperative training program in psychology. Consultants from the university have a just-across-the-street contact with the students practicum work, and VA staff psychologists are used by the university in planning curricula and in teaching. The training plan described here represents an attempt to use the close working relationship of university and hospital in planning and carrying out a meaningful training experience for first year graduate students. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cable Shielding Performance and CW Response

We show that the reference for the measurement of the shielding performance of a cable sheath should be the sheath current. However, unless the phase length of the cable is short, the response at the ends of the line will be sensitive to frequency even if the sheath current is uniform, and the coaxial line formed by the core wires and the sheath is matched at both ends. This is because the driving field in the coaxial line and the waves that it generates have different phase speeds and directions. We present supporting experimental data. Because of this effect it is not meaningful simply to state that a cable provides a specifled attenuation, except for a cable that is short at the highest frequency of interest. We discuss the effects of connectors and of cracks or holes in the sheath. Because the total leakage is proportional to the sum of leakages through the sheath (the connectors and the cracks) and not to their product, it is necessary to assign these contributions with some arbitrariness in order to compare them in decibels. We give an example that shows the importance of RF-tight connectors.     

Effects of over-expression of strictosidine synthase and tryptophan decarboxylase on alkaloid production by cell cultures of Catharanthus roseus

Cells of Catharanthus roseus (L.) G. Don were genetically engineered to over-express the enzymes strictosidine synthase (STR; EC 4.3.3.2) and tryptophan decarboxylase (TDC; EC 4.1.1.28), which catalyze key steps in the biosynthesis of terpenoid indole alkaloids (TIAs). The cultures established after Agrobacterium-mediated transformation showed wide phenotypic diversity, reflecting the complexity of the biosynthetic pathway. Cultures transgenic for Str consistently showed tenfold higher STR activity than wild-type cultures, which favored biosynthetic activity through the pathway. Two such lines accumulated over 200 mg.L-1 of the glucoalkaloid strictosidine and/or strictosidine-derived TIAs, including ajmalicine, catharanthine, serpentine, and tabersonine, while maintaining wild-type levels of TDC activity. Alkaloid accumulation by highly productive transgenic lines showed considerable instability and was strongly influenced by culture conditions, such as the hormonal composition of the medium and the availability of precursors. High transgene-encoded TDC activity was not only unnecessary for increased productivity, but also detrimental to the normal growth of the cultures. In contrast, high STR activity was tolerated by the cultures and appeared to be necessary, albeit not sufficient, to sustain high rates of alkaloid biosynthesis. We conclude that constitutive over-expression of Str is highly desirable for increased TIA production. However, given its complexity, limited intervention in the TIA pathway will yield positive results only in the presence of a favorable epigenetic environment.