Application of analysis techniques for low frequency interior noise and vibration of commercial aircraft

Finite element analysis (FEA), statistical energy analysis (SEA), and a power flow method (computer program PAIN) were used to assess low frequency interior noise associated with advanced propeller installations. FEA and SEA models were used to predict cabin noise and vibration and evaluate suppression concepts for structure-borne noise associated with the shaft rotational frequency and harmonics (less than 100 Hz). SEA and PAIN models were used to predict cabin noise and vibration and evaluate suppression concepts for airborne noise associated with engine radiated propeller tones. Both aft-mounted and wing-mounted propeller configurations were evaluated. Ground vibration test data from a 727 airplane modified to accept a propeller engine were used to compare with predictions for the aft-mounted propeller. Similar data from the 767 airplane was used for the wing-mounted comparisons

Evaluation of analysis techniques for low frequency interior noise and vibration of commercial aircraft

The application of selected analysis techniques to low frequency cabin noise associated with advanced propeller engine installations is evaluated. Three design analysis techniques were chosen for evaluation including finite element analysis, statistical energy analysis (SEA), and a power flow method using element of SEA (computer program Propeller Aircraft Interior Noise). An overview of the three procedures is provided. Data from tests of a 727 airplane (modified to accept a propeller engine) were used to compare with predictions. Comparisons of predicted and measured levels at the end of the first year's effort showed reasonable agreement leading to the conclusion that each technique had value for propeller engine noise predictions on large commercial transports. However, variations in agreement were large enough to remain cautious and to lead to recommendations for further work with each technique. Assessment of the second year's results leads to the conclusion that the selected techniques can accurately predict trends and can be useful to a designer, but that absolute level predictions remain unreliable due to complexity of the aircraft structure and low modal densities

La influencia de la relación resina/caseina sobre la performance del acabado

Se estudiaron dos emulsiones de resina, conjuntamente con una variación de la relación resina/caseína de 11,8:1 a 1,8:1, y su aplicación mediante felpa y soplete con aire comprimido o por el sistema airless spray (sin aire comprimido). Los cueros terminados con acatados que contienen mayor proporción de caseína exhibieron mayor permeabilidad al vapor de agua, pero menor porcentaje de deformación permanente. Otros cambios en la permeabilidad al vapor de agua, no están relacionados con la conservación de la forma conferida al cuero en la operación de premoldeado. La impregnación con una resina acrílica mejora la firmeza de la flor del cuero, y este beneficio aún se manifiesta luego del premoldeado. Los cueros no impregnados exhiben luego de dicha operación un pronunciado deterioro.The resin emulsion types have "been examined with a resin/casein ratio from 11,8:1 to 1,8:1 and applied hy pad and spray or airless spray. Increased casein content improves water vapour permeability and decreases the set hut other changes in water vapour permeability are not related to shape retention after preforming. Impregnation with an acrylate resin has been found to improved break, whibh has been retained after preforming, whereas inimpreg - nated leathers became more pipey. Other properties examined include cover, wet dry rub fastness, wet adhesion, flex resistance, etc

Influencia del recurtido, secado y método de aplicación del acabado sobre las características del cuero terminado

Se han comparado, los métodos tradicionales de aplicación del acabado (felpa y soplete de aire comprimido), con los nuevos métodos que emplean el soplete sin aire comprimido (airless spray gun) y la máquina de cortina (curtain coating machine), sobre cueros recurtidos a dos concentraciones diferentes, nutridos con distintos tipos de aceite y secados al aire o mediante el empleo de vacío. Los métodos de aplicación del acabado inciden sobre la casi totalidad de las propiedades examinadas (firmeza de la flor, brillo, resistencia a la flexión) del producto final. Un nuevo tipo de falla, similar a la que ocurre a baja temperatura, puede originarse al golpear el cuero a temperaturas normales, las cuales son lo suficientemente amplias como para que éste resista un ensayo de doble plegado.Pad and spray methods of applying finishes have been compared with airless spray gun and curtain outing with two levels of vegetable retannage, two types of fat-liquor and air or vacuum drying. It has been shown that the methods of application affect nearly all the characteristics examined such as break, whiteness, gloss and flex resistance of the finish. Foaming was less with finishes containing more casein but their flex resistance was lower. A previously unrecognised type of fault is one in which leather finish will withstand the double bend test, but splinter similarly to cold cracking when hit at normal temperatures

Wolbachia-Mediated Cytoplasmic Incompatibility Is Associated with Impaired Histone Deposition in the Male Pronucleus

Wolbachia is a bacteria endosymbiont that rapidly infects insect populations through a mechanism known as cytoplasmic incompatibility (CI). In CI, crosses between Wolbachia-infected males and uninfected females produce severe cell cycle defects in the male pronucleus resulting in early embryonic lethality. In contrast, viable progeny are produced when both parents are infected (the Rescue cross). An important consequence of CI–Rescue is that infected females have a selective advantage over uninfected females facilitating the rapid spread of Wolbachia through insect populations. CI disrupts a number of prophase and metaphase events in the male pronucleus, including Cdk1 activation, chromosome condensation, and segregation. Here, we demonstrate that CI disrupts earlier interphase cell cycle events. Specifically, CI delays the H3.3 and H4 deposition that occurs immediately after protamine removal from the male pronucleus. In addition, we find prolonged retention of the replication factor PCNA in the male pronucleus into metaphase, indicating progression into mitosis with incompletely replicated DNA. We propose that these CI-induced interphase defects in de novo nucleosome assembly and replication are the cause of the observed mitotic condensation and segregation defects. In addition, these interphase chromosome defects likely activate S-phase checkpoints, accounting for the previously described delays in Cdk1 activation. These results have important implications for the mechanism of Rescue and other Wolbachia-induced phenotypes

Field experiments on individual adaptation of the spider crab Inachus phalangium to its sea anemone host Anemonia viridis in the northern Adriatic Sea

We studied the adaptation of the spider crab Inachus phalangium (Fabricius, 1755) to one of its sea anemone host species, Anemonia viridis (Forsskål, 1775) in the coastal region of Rovinj, Croatia. Similar to other brachyuran species, Inachus spp. generally lives within the anemone to obtain protection from possible predators. Using removal and reintroduction experiments, this study investigates the protection mechanism and shows a loss of adaptation after a period of 10 days when the crabs are taken out of their host and kept solitary. Thirty-nine anemones from two different trial sites were marked individually and the inhabiting crabs were isolated to be released back into their individual hosts later. The reactions of the anemones were closely observed and characterized to determine the respective state of crab adaptation. As 35 out of 39 individuals provoked a defense /attack reaction of the anemone, it is concluded that the crabs possessed some sort of non-permanent protection mechanism that was lost during the test run (chi-square test, p < 0.00014). All tested crabs re-inhabited their host anemones within a maximum of 20 minutes after they had been reintroduced and stung by the anemones. Therefore, habituation to the host’s defense / attack mechanism is acquired individually and not genetically inherent to the species. The results are compared to adaptation and protection data on other decapod crustaceans and some anemonefishes

Perception of Climate Change in a Pacific Island City

According to the International Panel on Climate Change (IPCC 2007) small island states (SIS) will be severely affected by global climate change. Especially a rising sea level, increased frequency and intensity of extreme weather events and rising temperature will have serious impact on life on small islands in tropical regions. SIS hardly contribute to the emission of greenhouse gases, therefore their main challenge will be focussing on adaptation to prevent further damages

Biofilm Formation Induces C3a Release and Protects Staphylococcus epidermidis from IgG and Complement Deposition and from Neutrophil-Dependent Killing

BackgroundBiofilm formation is considered to be an important virulence factor of the opportunistic pathogen Staphylococcus epidermidis. We hypothesized that biofilm formation could interfere with the deposition of immunoglobulins and complement on the bacterial surface, leading to diminished activation of the complement system and protection from killing by human phagocytes MethodsThe killing of biofilm-encased and planktonically grown wild-type (wt) S. epidermidis and the killing of an isogenic biofilm-negative ica mutant (ica−) by human polymorphonuclear neutrophils (PMNs) were compared. C3a induction and deposition of C3b and immunoglobulin G (IgG) on the bacteria after opsonization with human serum were assessed by enzyme-linked immunosorbent assay, flow cytometry, and electron microscopy. The virulence of the bacterial strains was compared in a mouse model of catheter-associated infection ResultsBiofilm-embedded wt S. epidermidis was killed less well by human PMNs and induced more C3a than planktonically grown wt and ica− S. epidermidis. However, the deposition of C3b and IgG on the bacterial surface was diminished in biofilm-encased staphylococci. wt S. epidermidis was more virulent in implant-associated infections and was killed more slowly than ica− in ex vivo assays of killing by PMNs ConclusionsThe results indicate that prevention of C3b and IgG deposition on the bacterial surface contributes to the biofilm-mediated protection of S. epidermidis from killing by PMN

Host response to fungal infections - how immunology and host genetics could help to identify and treat patients at risk.

In spite of the ever-increasing incidence and poor outcome of invasive fungal infections in immune compromised patients, there is currently no reliable method to accurately predict the risk, to monitor the outcome and to treat these infections. Protective immunity against Candida and Aspergillus depends on a highly coordinated interaction between the innate and adaptive immune systems. Genetic and immunological defects in components of these networks result in increased risk of invasive fungal infections among patients undergoing chemotherapy or transplant recipients. We review the most important genetic and immunological factors that influence human susceptibility to Candida and Aspergillus infections and discuss the potential role of basic research to promote precision medicine for infectious diseases. We discuss how immunogenetic studies can help to provide tools for improved identification of high-risk patients and the development of tailored antifungal therapies

Dendritic cell quiescence during systemic inflammation driven by LPS stimulation of radioresistant cells in vivo

Dendritic cell (DC) activation is a prerequisite for T cell priming. During infection, activation can ensue from signaling via pattern-recognition receptors after contact with pathogens or infected cells. Alternatively, it has been proposed that DCs can be activated indirectly by signals produced by infected tissues. To address the contribution of tissue-derived signals, we measured DC activation in a model in which radioresistant cells can or cannot respond to lipopolysaccharide (LPS). We report that recognition of LPS by the radioresistant compartment is sufficient to induce local and systemic inflammation characterized by high circulating levels of tumor necrosis factor (TNF) α, interleukin (IL) 1β, IL-6, and CC chemokine ligand 2. However, this is not sufficient to activate DCs, whether measured by migration, gene expression, phenotypic, or functional criteria, or to render DC refractory to subsequent stimulation with CpG-containing DNA. Similarly, acute or chronic exposure to proinflammatory cytokines such as TNF-α ± interferon α/β has marginal effects on DC phenotype in vivo when compared with LPS. In addition, DC activation and migration induced by LPS is unimpaired when radioresistant cells cannot respond to the stimulus. Thus, inflammatory mediators originating from nonhematopoietic tissues and from radioresistant hematopoietic cells are neither sufficient nor required for DC activation in vivo