The characterisation of diesel cavitating flow using time-resolved light scattering

A conventional six-hole valve-covered orifice (VCO) injector nozzle has been modified in order to provide optical access to the region below the needle, and the nozzle passages. This has been achieved through the removal of the metal tip, and its replacement with a transparent acrylic tip of identical geometry. Elastic scattering of light obtained from the internal cavitating flow inside the nozzle holes of the optically accessible diesel injector tip was captured on a high speed electronic camera. The optical image data was obtained from a nozzle with a common rail pressure of 400 bar, and for two diesel fuels, in order to identify differences in cavitation behaviour. A set of 100 mean diesel fuel injection images were obtained from 30 fuel injection pulses, for each operating condition. The imaged mean cavitation occurring in the nozzle holes was converted to the mean proportion of nozzle hole area producing cavitation scattering. The mean cavitation area images were then analysed, and were able to demonstrate the inverse relationship between fuel mass injected and the relative area producing cavitation scattering

Synthesis of monodispersed Ag-doped bioactive glass nanoparticles via surface modification

© 2016 by the authors.Monodispersed spherical Ag-doped bioactive glass nanoparticles (Ag-BGNs) were synthesized by a modified Stöber method combined with surface modification. The surface modification was carried out at 25, 60, and 80 °C, respectively, to investigate the influence of processing temperature on particle properties. Energy-dispersive X-ray spectroscopy (EDS) results indicated that higher temperatures facilitate the incorporation of Ag. Hydroxyapatite (HA) formation on Ag-BGNs was detected upon immersion of the particles in simulated body fluid for 7 days, which indicated that Ag-BGNs maintained high bioactivity after surface modification. The conducted antibacterial assay confirmed that Ag-BGNs had an antibacterial effect on E. coli. The above results thereby suggest that surface modification is an effective way to incorporate Ag into BGNs and that the modified BGNs can remain monodispersed as well as exhibit bioactivity and antibacterial capability for biomedical applications

Adrenomedullin receptors on human T cells are glucocorticoid-sensitive

Adrenomedullin (AM) is a novel vasodilatatory peptide which acts primarily through the calcitonin receptor-like receptor (CLR) in combination with either receptor-activity-modifying-protein (RAMP) 2 or 3 (forming receptors, AM 1 and AM2 respectively). AM plays an important role during inflammation, with its expression increasing following cytokine treatment, promoting macrophage action in situ and high expression by T cells during hypoxic conditions. Examination of T cell AM receptor expression has previously been incomplete, hence we here consider the presentation of AM receptors and their responsiveness to AM and glucocorticoids (GC). AM receptor expression was examined by PCR and flow cytometry in primary human T cells, revealing that RAMP2, 3 and CLR are physiologically expressed in unstimulated T cells, both intracellularly and on the cell surface. PHA stimulation decreased receptor proteins, significantly so for CLR and RAMP3. Incubation with AM elicited limited receptor alterations however, GC treatment (10- 6 M; 24 h) markedly affected cell surface expression, significantly increasing receptor components in unstimulated cells and significantly decreasing the same in stimulated T cells. Our findings indicate that human T cells utilize both AM1 and AM2 receptors, which are GC-sensitive in an activation-state dependent manner. © 2012 Elsevier B.V

Virtual mechanical product disassembly sequences based on disassembly order graphs and time measurement units

Recently, the approach that defines the total life cycle assessment (LCA) and the end of life (EoL) in the early design phases is becoming even more promising. Literature evidences many advantages in terms of the saving of costs and time and in the fluent organization of the whole design process. Design for disassembly (DfD) offers the possibility of reducing the time and cost of disassembling a product and accounts for the reusing of parts and of the dismantling of parts, joints, and materials. The sequence of disassembly is the ordered way to extract parts from an assembly and is a focal item in DfD because it can deeply influence times and operations. In this paper, some disassembly sequences are evaluated, and among them, two methods for defining an optimal sequence are provided and tested on a case study of a mechanical assembly. A further sequence of disassembly is provided by the authors based on experience and personal knowledge. All three are analyzed by the disassembly order graph (DOG) approach and compared. The operations evaluated have been converted in time using time measurement units (TMUs). As result, the best sequence has been highlighted in order to define a structured and efficient disassembly

Rare events, escape rates and quasistationarity: some exact formulae

We present a common framework to study decay and exchanges rates in a wide class of dynamical systems. Several applications, ranging form the metric theory of continuons fractions and the Shannon capacity of contrained systems to the decay rate of metastable states, are given

The characterisation of diesel nozzle flow using high speed imaging of elastic light scattering

Two identical, conventional six-hole, valve-covered orifice (VCO) diesel injectors have been modified in order to provide optical access to the region below the needle, and the nozzle-flow passages. This has been achieved through the removal of the metal tips, and their replacement with transparent acrylic tips of identical geometry. These two identical injectors were employed in order to offer comparability between the measurements. One of them had a dark, anodised inner surface at the base, while the other had a silvered inner surface at the base. Elastic scattering of incident white light from the internal cavitating flow inside the nozzle holes of the optically accessible diesel injector tips was captured on a high-speed electronic camera. The optical image data was obtained for three injector rail pressures ranging from 200 bar to 400 bar, and for five diesel fuels of varying density, viscosity, and distillation profile, in order to identify variations in cavitation flow behaviour inside the nozzle hole passages. A set of mean time-resolved diesel fuel flow images were obtained from 30 successive fuel injection pulses, for each operating condition, for each injector. The mean cavitation image occurring in the nozzle holes was converted to the mean proportion of nozzle hole area producing cavitation-induced optical scattering. The mean normalised area images were then analysed, and were able to demonstrate the anticipated inverse relationship between injected fuel mass and cavitation volume fraction (indicated by mean normalised area), and the effect of fuel viscosity and distillation profile on cavitation volume fraction (again indicated by mean normalised area)

Energy transfer in a fast-slow Hamiltonian system

We consider a finite region of a lattice of weakly interacting geodesic flows on manifolds of negative curvature and we show that, when rescaling the interactions and the time appropriately, the energies of the flows evolve according to a non linear diffusion equation. This is a first step toward the derivation of macroscopic equations from a Hamiltonian microscopic dynamics in the case of weakly coupled systems

A structured index describing the ease of disassembly for handcrafted product

Both economic and environmental aspects significantly influence the design process since the early phases of preliminary design. The total Life Cycle Assessment (LCA) and the End of Life (EoL) of products have to be defined in the early design phases too but, for industrial products that are not feasible to automatic production, they are hard issues. However, the EoL of products can be assessed by evaluating the disassembly of joints assembling the product, even when the production process is subject to an important contribute of workmanship. In this paper, a useful method is proposed to analyze the disassembly plant of products, in order to optimize the design process in the early preliminary phases. The method quantitatively evaluates a Disassembly Index that describes the attitude of a product to be disassembled. A case study describes the disassembly attitude of structural subassemblies of a sailboat. In order to test the applicability of the model described to both manual and automated disassembly, a further application of the method is proposed on a Computer CPU. As result, the model demonstrated good sensitiveness to the testing of products quite different for dimensions, number of components, manufacturing processes and, in all cases, it quantified the disassembly easiness with good relevance

Eigenfunctions for smooth expanding circle maps

We construct a real-analytic circle map for which the corresponding Perron-Frobenius operator has a real-analytic eigenfunction with an eigenvalue outside the essential spectral radius when acting upon $C^1$-functions.Comment: 10 pages, 2 figure