Abstract
This paper presents an analytical study on optimization of a laminated composite wing structure for achieving a maximum flutter speed and a minimum weight without strength penalty. The ...investigation is carried out within the range of incompressible airflow and subsonic speed. In the first stage of the optimization, attention has been paid mainly to the effect on flutter speed of the bending, torsion and, more importantly, the bending-torsional coupling rigidity, which is usually associated with asymmetric laminate lay-up. The study has shown that the torsional rigidity plays a dominant role, while the coupling rigidity has also quite a significant effect on the flutter speed. In the second stage of the optimization, attention has been paid to the weight and laminate strength of the wing structure, which is affected by the variation in laminate lay-up in the first stage. Results from a thin-walled wing box made of laminated composite material show that up to 18 per cent increase in flutter speed and 13 per cent reduction in weight can be achieved without compromising the strength. The investigation has shown that a careful choice of initial lay-up and design variables leads to a desirable bending, torsional and coupling rigidities, with the provision of an efficient approach when achieving a maximum flutter speed with a minimum mass of a composite wing.
Chromosome 13 is the largest acrocentric human chromosome. It carries genes involved in cancer including the breast cancer type 2 (BRCA2) and retinoblastoma (RB1) genes, is frequently rearranged in ...B-cell chronic lymphocytic leukaemia, and contains the DAOA locus associated with bipolar disorder and schizophrenia. We describe completion and analysis of 95.5 megabases (Mb) of sequence from chromosome 13, which contains 633 genes and 296 pseudogenes. We estimate that more than 95.4% of the protein-coding genes of this chromosome have been identified, on the basis of comparison with other vertebrate genome sequences. Additionally, 105 putative non-coding RNA genes were found. Chromosome 13 has one of the lowest gene densities (6.5 genes per Mb) among human chromosomes, and contains a central region of 38 Mb where the gene density drops to only 3.1 genes per Mb.
The polarograms, the current-pH, E½-pH, current vs √h, current-concentration plots and slopes of log ī vs. log h (uncorrected) plots of active components of Artemisia maritima leaf- and ...flowerextracts in 1% HClO4 solution prove the irreversible diffusion-controlled nature of limiting currents, similar to those of santonin. Milli-coulometry proves a two-electron process at pH values of 4.5 and 9.3. Calibration curve (limiting current vs concentration) of santonin at pH 5.3 shows that the air-dried leaves and flowers of the plant contain 0.96% and 0.98% of santonin respectively.
Focused ion beams provide new opportunities to create small nanofabricated structures. Materials where this technique is successfully applied are different from those that are widely used in e-beam ...or photolithography processes. Arrays of holes have been fabricated in several layered superconductors, such as the transition metal dichalcogenides. A focused ion beam system can be also used to deposit superconducting material. A Ga beam is used to decompose a precusor W(CO) sub(6)(CO)6 molecule, giving an amorphous mixture of W-C-Ga-O which is superconducting below liquid helium temperatures. The amorphous nature of the deposit gives isotropic superconducting features, and vortex pinning is determined by the surface topography (or film thickness). Here we present vortex lattice images in an amorphous thin film with a nanofabricated array of dots. We find vortex confinement within the dots and inhomogeneous vortex distributions with large magnetic field gradients (around a Tesla in 10-20 nm). We discuss scaling behavior of the vortex lattice after nanofabrication.
Three different spinel compositions with MgO:Al2O3 molar ratios 2:1, 1:1 and 1:2 were studied using TiO2 as an additive up to 2 wt%. The solid state reaction sintering technique was employed for all ...the compositions in the temperature range of 1550-1650 C. Reduction of particle size was achieved by attrition milling. Sintered products were characterised in terms of densification and shrinkage studies, phase analysis, strength evaluation (both at ambient temperature and at elevated temperature), strength retention after a different number of thermal cycles at 1000 C, quantitative elemental analysis and microstructural studies. 19 refs.
A mixture of lysophosphatidylcholines (lyso-PCs) are generated during blood storage and are etiologic in models of acute lung injury. We hypothesize that lyso-PCs stimulate polymorphonuclear ...neutrophils (PMNs) through Ca(2)(+)-dependent signaling. The lyso-PC mix (0.45-14.5 micro M) and the individual lyso-PCs primed formyl-Met-Leu-Phe (fMLP) activation of the oxidase (1.8- to 15.7-fold and 1.7- to 14.8-fold; P<0.05). Labeled lyso-PCs demonstrated a membrane association with PMNs and caused rapid increases in cytosolic Ca(2)(+). Receptor desensitization studies implicated a common receptor or a family of receptors for the observed lyso-PC-mediated changes in PMN priming, and cytosolic Ca(2)(+) functions were pertussis toxin-sensitive. Lyso-PCs caused rapid serine phosphorylation of a 68-kD protein but did not activate mitogen-activated protein kinases or cause changes in tyrosine phosphorylation. With respect to alterations in PMN function, lyso-PCs caused PMN adherence, increased expression of CD11b and the fMLP receptor, reduced chemotaxis, provoked changes in morphology, elicited degranulation, and augmented fMLP-induced azurophilic degranulation (P<0.05). Cytosolic Ca(2)(+) chelation inhibited lyso-PC-mediated priming of the oxidase, CD11b surface expression, changes in PMN morphology, and serine phosphorylation of the 68-kD protein. In conclusion, lyso-PCs affect multiple PMN functions in a Ca(2)(+)-dependent manner that involves the activation of a pertussis toxin-sensitive G-protein.
A variety of directional control-response relationships are currently found in mining equipment. Two experiments were conducted in a virtual environment to determine optimal direction ...control-response relationships in a wide variety of circumstances. Direction errors were measured as a function of control orientation (horizontal or vertical), location (left, front, right) and directional control-response relationships. The results confirm that the principles of consistent direction and visual field compatibility are applicable to the majority of situations. An exception is that fewer direction errors were observed when an upward movement of a horizontal lever or movement of a vertical lever away from the participants caused extension (lengthening) of the controlled device, regardless of whether the direction of movement of the control is consistent with the direction in which the extension occurs. Further, both the control of slew by horizontally oriented controls and the control of device movements in a frontal plane by the perpendicular movements of vertical levers were associated with relatively high rates of directional errors, regardless of the directional control-response relationship, and these situations should be avoided.
Statement of Relevance:The results are particularly applicable to the design of mining equipment such as drilling and bolting machines, and have been incorporated into MDG35.1 Guideline for bolting & drilling plant in mines (Industry & Investment NSW, 2010). The results are also relevant to the design of any equipment where vertical or horizontal levers are used to control the movement of equipment appendages, e.g. cranes mounted to mobile equipment and the like.
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