Product and process information interactions in assembly decision support systems

A characteristic of concurrent engineering is the intensive information interchange between areas that are involved through the product life cycle. Shared information structures to integrate different software applications have become necessary to support effectively the interchange of information. While . much work has been done into the concepts of Product and Manufacturing Models, there is a need to make them able to support Assembly related activities. The research reported in this thesis explores and defines the structures of a Product Model and. a Manufacturing Model to support assembly related information. These information models support the product development process, especially during the early stages of the product life cycle. The structures defined for the models allow information interactions between them and with application software; these interactions are essential to support an effective concurrent environment. The Product Model is a source and repository of the product information, whilst the Manufacturing Model holds information about the manufacturing processes and resources of an enterprise. A combination of methods was proposed in order to define the structure for the information models. An experimental software system was created and used to show that the structure defined for the Product Model and the Manufacturing Model can support· a range of assembly-related software applications through the concurrent development of the product, system and process, from conceptual design through to planning. The applications implemented in the experimental system were Design for Assembly and Assembly Process Planning. The real data used for the tests was obtained from an industrial collaborator who manufactures large electrical machines. This research contributes to the understanding of. the general structural requirements of the decision support systems based on information models, and to the integration of Design for Assembly and Assembly Process Planning

Wind Turbine Failures - Tackling current Problems in Failure Data Analysis

The wind industry has been growing significantly over the past decades, resulting in a remarkable increase in installed wind power capacity. Turbine technologies are rapidly evolving in terms of complexity and size, and there is an urgent need for cost effective operation and maintenance (O&M) strategies. Especially unplanned downtime represents one of the main cost drivers of a modern wind farm. Here, reliability and failure prediction models can enable operators to apply preventive O&M strategies rather than corrective actions. In order to develop these models, the failure rates and downtimes of wind turbine (WT) components have to be understood profoundly. This paper is focused on tackling three of the main issues related to WT failure analyses. These are, the non-uniform data treatment, the scarcity of available failure analyses, and the lack of investigation on alternative data sources. For this, a modernised form of an existing WT taxonomy is introduced. Additionally, an extensive analysis of historical failure and downtime data of more than 4300 turbines is presented. Finally, the possibilities to encounter the lack of available failure data by complementing historical databases with Supervisory Control and Data Acquisition (SCADA) alarms are evaluated

An analytic model for a cooperative ballistic deposition in one dimension

We formulate a model for a cooperative ballistic deposition (CBD) process whereby the incoming particles are correlated with the ones already adsorbed via attractive force. The strength of the correlation is controlled by a tunable parameter $a$ that interpolates the classical car parking problem at $a=0$, the ballistic deposition at $a=1$ and the CBD model at $a>1$. The effects of the correlation in the CBD model are as follows. The jamming coverage $q(a)$ increases with the strength of attraction $a$ due to an ever increasing tendency of cluster formation. The system almost reaches the closest packing structure as $a\to\infty$ but never forms a percolating cluster which is typical to 1D system. In the large $a$ regime, the mean cluster size $k$ increases as $a^{1/2}$. Furthermore, the asymptotic approach towards the closest packing is purely algebraic both with $a$ as $q(\infty)-q(a) \sim a^{-1/2}$ and with $k$ as $q(\infty)-q(k) \sim k^{-1}$ where $q(\infty)\simeq 1$.Comment: 9 pages (in Revtex4), 9 eps figures; Submitted to publicatio

Barriers to Depression Treatment among Low-income, Latino Emergency Department Patients

Objectives. Low-income and Latinos use the emergency department (ED) as a primary source of care. Also, the depression prevalence in ED patients is high, making the ED a compelling venue for depression screening and intervention. This study examined barriers and facilitators to depression treatment among low-income, predominantly Latino ED patients. Methods. We conducted telephone interviews with 24 ED patients (18-62 years of age, 79% female) who dropped out of a depression treatment intervention. Using grounded theory, we analyzed perceptions of depression and treatment, and barriers and facilitators to mental health treatment. Results. Although most patients acknowledged signs of depression, there was a lack of readiness to seek help. Patients reported negative perceptions about anti-depressant medication, even if they had no previous use. Barriers to treatment included transportation concerns, employment/unemployment, patient-provider issues, and immigrant documentation. Identified facilitators included consistent provider advice and “talking.” This study introduced new misunderstanding and miscommunication barriers

The transfusion threshold for upper gastrointestinal bleeding is a hemoglobin of 7.0 g/dl or less

A critical appraisal and clinical application of Villanueva C, Colomo A, Bosch A, Concepcion M, Hernandez-Gea V, Aracil C. Transfusion strategies for acute upper gastrointestinal bleeding. New Eng J Med. 2013;368(1):11-21. doi: 10.1056/NEJMoa121180

Using the clustering coefficient to guide a genetic-based communities finding algorithm

The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-642-23878-9_20Proceedings of 12th International Conference IDEAL, Norwich, UK, September 7-9, 2011.We describe an approach taken for automatically associating entries from an on-line encyclopedia with concepts in an ontology or a lexical semantic network. It has been tested with the Simple English Wikipedia and WordNet, although it can be used with other resources. The accuracy in disambiguating the sense of the encyclopedia entries reaches 91.11% (83.89% for polysemous words). It will be applied to enriching ontologies with encyclopedic knowledge

Butyltin compounds in a sediment core from the old Tilbury basin, London, UK

Sections from a sediment core taken from the River Thames were analysed for butyltin species using gas chromatography with species-specific isotope dilution mass spectrometry. Results demonstrated that in most samples tributyltin concentrations of 20–60 ng/g accounted for <10% of the total butyltin species present, which is in agreement with data from other sediment samples which were historically contaminated with tributyltin. Vertical distribution of the organotin residues with depth throughout the core, with data on organochlorine compounds and heavy metals allowed for the construction of a consistent hypothesis on historical deposition of contaminated sediments. From this it was possible to infer that the concentrations of tributyltin in sediments deposited during the early 1960s were in the order of 400–600 lg/g by using degradation rate constants derived by other workers. Such values fall well within the range quoted for harbour sediments in the literature

Controlled delivery of tauroursodeoxycholic acid from biodegradable microspheres slows retinal degeneration and vision loss in P23H rats

Successful drug therapies for treating ocular diseases require effective concentrations of neuroprotective compounds maintained over time at the site of action. The purpose of this work was to assess the efficacy of intravitreal controlled delivery of tauroursodeoxycholic acid (TUDCA) encapsulated in poly(D, L-lactic-co-glycolic acid) (PLGA) microspheres for the treatment of the retina in a rat model of retinitis pigmentosa. PLGA microspheres (MSs) containing TUDCA were produced by the O/W emulsion-solvent evaporation technique. Particle size and morphology were assessed by light scattering and scanning electronic microscopy, respectively. Homozygous P23H line 3 rats received a treatment of intravitreal injections of TUDCA-PLGA MSs. Retinal function was assessed by electroretinography at P30, P60, P90 and P120. The density, structure and synaptic contacts of retinal neurons were analyzed using immunofluorescence and confocal microscopy at P90 and P120. TUDCA-loaded PLGA MSs were spherical, with a smooth surface. The production yield was 78%, the MSs mean particle size was 23 mu m and the drug loading resulted 12.5 +/- 0.8 mu g TUDCA/mg MSs. MSs were able to deliver the loaded active compound in a gradual and progressive manner over the 28-day in vitro release study. Scotopic electroretinografic responses showed increased ERG a- and b-wave amplitudes in TUDCA-PLGA-MSstreated eyes as compared to those injected with unloaded PLGA particles.TUDCA-PLGAMSs- treated eyes showed more photoreceptor rows than controls. The synaptic contacts of photoreceptors with bipolar and horizontal cells were also preserved in P23H rats treated with TUDCA-PLGA MSs. This work indicates that the slow and continuous delivery of TUDCA from PLGA-MSs has potential neuroprotective effects that could constitute a suitable therapy to prevent neurodegeneration and visual loss in retinitis pigmentosa

Three strongly correlated charged bosons in a one-dimensional harmonic trap: natural orbital occupancies

We study a one-dimensional system composed of three charged bosons confined in an external harmonic potential. More precisely, we investigate the ground-state correlation properties of the system, paying particular attention to the strong-interaction limit. We explain for the first time the nature of the degeneracies appearing in this limit in the spectrum of the reduced density matrix. An explicit representation of the asymptotic natural orbitals and their occupancies is given in terms of some integral equations.Comment: 6 pages, 4 figures, To appear in European Physical Journal