178 research outputs found

    Neural network applications in polymerization processes

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    Neural networks currently play a major role in the modeling, control and optimization of polymerization processes and in polymer resin development. This paper is a brief tutorial on simple and practical procedures that can help in selecting and training neural networks and addresses complex cases where the application of neural networks has been successful in the field of polymerization.401418Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    Estudios de caso dentro del entorno COVID-19 a nivel internacional en 2020

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    Se realizó una investigación sobre la situación de las PYMES en distintos países para conocer las estrategias que implementaron durante la pandemia para seguir laborando. Se hicieron dos documentos, un Excel que incluye la información obtenida separando redes sociales y noticias, y un mural que incluye las imágenes de las estrategias implementadas por las empresas. Esta investigación tuvo como objetivo conocer el comportamiento de las PYMES durante la pandemia, para posteriormente realizar un análisis de las estrategias implementadas, además de tener una comparativa sobre las PYMES en México y otros países, para finalmente realizar estrategias; esta investigación también podrá beneficiar a un tercero del proyecto. Posteriormente junto con el equipo de Etnografía en Línea se realizó un cruce de información para elaborar 8 Value Proposition Canvas, categorías dadas por el equipo Estudios de Casos, para obtener un análisis más completo de la situación actual y un panorama más claro de las acciones que están tomando las empresas dependiendo su giro para de esta manera saber qué acciones se pueden tomar en un futuro. El reporte brinda al lector el beneficio de conocer los aciertos y mejoras de las empresas, para así aprender de las experiencias ajenas y tener una visión distinta sobre la situación, además de poder plasmar este nuevo conocimiento a su negocio dependiendo el giro, este reporte también servirá de apoyo a los alumnos que realicen su PAP en el periodo Otoño 2020. En este proyecto quedó por resolver el cruce de información con otros equipos de trabajo y la implementación de las estrategias realizadas por los equipos en un caso real.ITESO, A.C

    Cellulose nanocrystal-based poly(butylene adipate-co-terephthalate) nanocomposites covered with antimicrobial silver thin films

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    In this study, we reported the preparation and prospective application of the nanocomposites of poly(butylene adipate-co-terephthalate) (PBAT) reinforced with cellulose nanocrystals (CNCs). CNCs were isolated from bleached sugarcane bagasse by acid hydrolysis and functionalized with adipic acid. Nanocomposites were prepared with different concentration of CNCs (0.8, 1.5, and 2.3 wt% CNC) by solution-casting method and then were covered with silver thin film by magnetron sputtering. The results showed that the surface modification increased the degree of crystallinity of nanocrystals from 51% to 56%, decreasing their length and diameter. Moreover, AFM-IR spectroscopy revealed that the modified CNCs were covered by adipic acid molecules, improving the dispersion of nanocrystals in PBAT. Well-dispersed modified CNCs acted as heterogeneous nuclei for crystallization of PBAT, and increased the storage modulus of the polymer by more than 200%. These improvements in thermal and mechanical properties of CNC-based PBAT associated with the decrease of 56% in the Escherichia coli biofilm formation on nanocomposites (antibacterial properties) qualify the CNC/PBAT nanocomposites covered with silver thin films to be used as food packaging. POLYM. ENG. SCI., 59:E356-E365, 2019. (c) 2019 Society of Plastics Engineers59s22E356E365CNPQ - Conselho Nacional de Desenvolvimento Científico e TecnológicoNÃO CONSTANÃO CONSTA2016/09588-9CAPES - Coordenação de Aperfeiçoamento de Pessoal e Nível SuperiorFAPESP – Fundação de Amparo à Pesquisa Do Estado De São Paul

    A Lean Six Sigma framework for the reduction of ship loading commercial time in the iron ore pelletising industry

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    © 2016 Informa UK Limited, trading as Taylor & Francis Group. Abstract: Evidence suggests that specifically designed frameworks to implement Lean Six Sigma (LSS) projects to tackle particular problems are more effective than ‘generic’ versions. This paper proposes an implementation framework to effectively deploy LSS to improve a key operation and performance indicator, i.e. ship loading commercial time, of one of the largest world producer of iron ore. This article therefore contributes with a refined framework to effectively implement LSS, and documents its successful application and effectiveness within the context of the case organisation. The LSS framework and project contributed in helping the studied organisation to improve both the capability of its ship loading process and commercial time by more than 30%, resulting in operational savings in the range of $300,000 USD per year. The systematic nature of the framework proposed also helped the organisation to establish a standardised routine to improve its operations. Managerial implications exposing the challenges faced during the implementation of LSS are also discussed to serve as lessons learnt to be considered in other LSS projects. Managers and engineers incharge of improving operations and processes can benefit from this paper as it can be used as a guide to direct the conduction of LSS projects and the empirical application of its principles and tools

    Polymer composites reinforced with natural fibers and nanocellulose in the automotive industry: a short review

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    Environmental concerns and cost reduction have encouraged the use of natural fillers as reinforcement in polymer composites. Currently, a wide variety of reinforcement, such as natural fibers and nanocellulose, are used for this purpose. Composite materials with natural fillers have not only met the environmental appeal, but also contribute to developing low-density materials with improved properties. The production of natural fillers is unlimited around the world, and many species are still to be discovered. Their processing is considered beneficial since the natural fillers do not cause corrosion or great wear of the equipment. For these reasons, polymer reinforced with natural fillers has been considered a good alternative for obtaining ecofriendly materials for several applications, including the automotive industry. This review explores the use of natural fillers (natural fibers, cellulose nanocrystals, and nanofibrillated cellulose) as reinforcement in polymer composites for the automotive industry323172016/09588-9; 2016/09588-9; 2016/09588-9CAPES - Coordenação de Aperfeiçoamento de Pessoal e Nível SuperiorCNPQ - Conselho Nacional de Desenvolvimento Científico e TecnológicoFAPESP – Fundação de Amparo à Pesquisa Do Estado De São Paul

    Assessment of Pneumonia in Older Adults: Effect of Functional Status

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    Evaluate the effect of preadmission functional status on severity of pneumonia, length of hospital stay (LOS), and all-cause 30-day and 1-year mortality of adults aged 60 and older and to understand the effect of pneumonia on short-term functional impairment. DESIGN : Prospective cohort study. SETTING : University hospital. PARTICIPANTS : One hundred twelve patients with radiograph-proven pneumonia (mean age 74.6) were enrolled. MEASUREMENTS : Functional status and comorbidities were assessed using the Functional Autonomy Measurement System (SMAF) and Charlson Comorbidity Index. Clinical information was used to calculate the Pneumonia Prognostic Index (PPI). RESULTS : Eighty-four (75%) patients were functionally independent (FI) before admission, with a SMAF score of 40 or lower. Dementia and aspiration history were higher in the group that was functionally dependent (FD) before admission ( P <.001). The FI group had less-severe pneumonia per the PPI and shorter mean LOS±standard deviation (5.62±0.51 days) than the FD group (11.42±2.58, P <.004). The FI group had lower 1-year mortality (19/65, 23%) than the FD group (14/28, 50%), and the difference remained significant after adjusting for Charlson Index and severity of illness ( P =.009). All patients lost function after admission, with loss being more pronounced in the FI group (mean change 19.24±12.9 vs 4.72±6.55, P <.001). CONCLUSION : Older adults who were FI before admission were more likely to present with less-severe pneumonia and have a shorter LOS. In addition, further loss of function was common in these patients. Assessment of function before and during hospitalization should be an integral part of clinical evaluation in all older adults with pneumonia.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66281/1/j.1532-5415.2006.00797.x.pd

    Mobility and other predictors of hospitalization for urinary tract infection: a retrospective cohort study

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    Abstract Background Many hospitalizations for residents of skilled nursing facilities are potentially avoidable. Factors that could prevent hospitalization for urinary tract infection (UTI) were investigated, with focus on patient mobility. Methods A retrospective cohort study was conducted using 2003–2004 data from the Centers for Medicare and Medicaid Services. The study included 408,192 residents of 4267 skilled nursing facilities in California, Florida, Michigan, New York, and Texas. The patients were followed over time, from admission to the skilled nursing facility to discharge or, for those who were not discharged, for 1 year. Cox proportional hazards regression was conducted with hospitalization for UTI as the outcome. Results The ability to walk was associated with a 69% lower rate of hospitalization for UTI. Maintaining or improving walking ability over time reduced the risk of hospitalization for UTI by 39% to 76% for patients with various conditions. For residents with severe mobility problems, such as being in a wheelchair or having a missing limb, maintaining or improving mobility (in bed or when transferring) reduced the risk of hospitalization for UTI by 38% to 80%. Other potentially modifiable predictors included a physician visit at the time of admission to the skilled nursing facility (Hazard Ratio (HR), 0.68), use of an indwelling urinary catheter (HR, 2.78), infection with Clostridium difficile or an antibiotic-resistant microorganism (HR, 1.20), and use of 10 or more medications (HR, 1.31). Patient characteristics associated with hospitalization for UTI were advancing age, being Hispanic or African-American, and having diabetes mellitus, renal failure, Parkinson's disease, dementia, or stroke. Conclusion Maintaining or improving mobility (walking, transferring between positions, or moving in bed) was associated with a lower risk of hospitalization for UTI. A physician visit at the time of admission to the skilled nursing facility also reduced the risk of hospitalization for UTI.http://deepblue.lib.umich.edu/bitstream/2027.42/112369/1/12877_2008_Article_125.pd

    Functional upgrading in China’s export processing sector

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    Functional upgrading occurs when a firm acquires more sophisticated functions within an existing value chain. In this paper, we analyze if there is evidence of this type of upgrading in China’s export processing regime by investigating dynamics in the relative prevalence of Import & Assembly (IA) versus Pure Assembly (PA) processing trade over the period 2000-2013. Firms in both regimes provide similar manufacturing services to foreign companies, but IA firms also conduct the sophisticated tasks of quality control, searching, financing and storing imported materials. Consistent with a trend of functional upgrading, we show that the share of IA trade in total processing trade has increased rapidly during the period 2000-2006, both overall and within product categories. Furthermore, we find that this trend has gone hand in hand with improvements in a sector’s labor productivity and unit values. Against expectations, we find that this process has slowed down notably during the period 2006-2013.status: publishe

    Survival and long-term maintenance of tertiary trees in the Iberian Peninsula during the Pleistocene. First record of Aesculus L.

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    The Italian and Balkan peninsulas have been places traditionally highlighted as Pleistocene glacial refuges. The Iberian Peninsula, however, has been a focus of controversy between geobotanists and palaeobotanists as a result of its exclusion from this category on different occasions. In the current paper, we synthesise geological, molecular, palaeobotanical and geobotanical data that show the importance of the Iberian Peninsula in the Western Mediterranean as a refugium area. The presence of Aesculus aff. hippocastanum L. at the Iberian site at Cal Guardiola (Tarrasa, Barcelona, NE Spain) in the Lower– Middle Pleistocene transition helps to consolidate the remarkable role of the Iberian Peninsula in the survival of tertiary species during the Pleistocene. The palaeodistribution of the genus in Europe highlights a model of area abandonment for a widely-distributed species in the Miocene and Pliocene, leading to a diminished and fragmentary presence in the Pleistocene and Holocene on the southern Mediterranean peninsulas. Aesculus fossils are not uncommon within the series of Tertiary taxa. Many appear in the Pliocene and suffer a radical impoverishment in the Lower–Middle Pleistocene transition. Nonetheless some of these tertiary taxa persisted throughout the Pleistocene and Holocene up to the present in the Iberian Peninsula. Locating these refuge areas on the Peninsula is not an easy task, although areas characterised by a sustained level of humidity must have played an predominant role

    Late-Holocene climatic variability south of the Alps as recorded by lake-level fluctuations at Lake Ledro, Trentino, Italy

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    International audienceA lake-level record for the late Holocene at Lake Ledro (Trentino, northeastern Italy) is presented. It is based on the sediment and pollen analysis of a 1.75 m high stratigraphic section observed on the southern shore (site Ledro I) and a 3.2 m long sediment core taken from a littoral mire on the southeastern shore (site Ledro II). The chronology is derived from 15 radiocarbon dates and pollen stratigraphy. The late-Holocene composite record established from these two sediment sequences gives evidence of centennial-scale fluctuations with highstands at c. 3400, 2600, 1700, 1200 and 400 cal. BP, in agreement with various palaeohydro-logical records established in central and northern Italy, as well as north of the Alps. In addition, high lake-level conditions at c. 2000 cal. BP may be the equivalent of stronger river discharge observed at the same time in Central Italy's rivers. In agreement with the lake-level record of Accesa (Tuscany), the Ledro record also suggests a relatively complex palaeohydrological pattern for the period around 4000 cal. BP. On a millennial scale, sediment hiatuses observed in the lower part of the Ledro I sediment sequence indicate that, except for a high-stand occurring just after 7500 cal. BP, lower lake levels generally prevailed rather before c. 4000 cal. BP than afterwards. Finally, the lake-level data obtained at Lake Ledro indicate that the relative continuity of settlements in humid areas of northern Italy during the Bronze Age (in contrast to their general abandonment north of the Alps between c. 3450 and 3150 cal. BP), does not reflect different regional patterns of climatic and palaeohy-drological conditions. In contrast, the rise in lake level dated to c. 3400 cal. BP at Ledro appears to coincide with a worldwide climate reversal, observed in both the hemispheres, while palaeoenvironmental and archaeological data collected at Lake Ledro may suggest, as a working hypothesis, a relative emancipation of proto-historic societies from climatic conditions
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