14,222 research outputs found
Setting the optimal sheet thickness distribution for plastics thermoforming by multi-objective optimization
Thermoforming is a thermoplastic processing technique commonly used in the rigid packaging industry. The process comprises a heating stage, which aims at allowing the sheet to acquire the required deformability, a deformation stage, in which the sheets conform to the mould surface, and, finally, a cooling stage, which allows the part to be extracted from the mould without distorting. Since there are several processing variables associated with those stages, optimizing the thermoforming process is a complex task. In this work, a multi-objective optimization evolutionary algorithm is proposed to optimize the plastics thermoforming process. For that purpose, the thickness distribution of the final part was optimized considering that it is manufactured from uniform temperature sheets with different thickness distributions, such as constant and spline and concentric profiles. The aims were to minimize the sheet volume, as it implies less material use; assure a minimum value for the part thickness distribution, to avoid hindering its mechanical behavior; and minimize the thickness heterogeneity, i.e., the difference between the thickness of the part and a reference thickness. The Pareto optimal solutions found by the algorithm correspond to different thickness profiles for the three different sheet shapes. In all cases, an improvement of the different profiles along the successive generations of the evolutionary algorithm was obtained, which are related to the objectives considered. Moreover, the initial sheet thickness distribution was found to clearly influence the optimization process. The results obtained for these three different initial sheet shapes indicate that the proposed methodology is valid, providing solutions with physical meaning and with great potential to be applied in more complex cases
Multi-objective optimization of plastics thermoforming
The practical application of a multi-objective optimization strategy based on evolutionary algorithms was proposed to optimize the plastics thermoforming process. For that purpose, in this work, differently from the other works proposed in the literature, the shaping step was considered individually with the aim of optimizing the thickness distribution of the final part originated from sheets characterized by different thickness profiles, such as constant thickness, spline thickness variation in one direction and concentric thickness variation in two directions, while maintaining the temperature constant. As far we know, this is the first work where such a type of approach is proposed. A multi-objective optimization strategy based on Evolutionary Algorithms was applied to the determination of the final part thickness distribution with the aim of demonstrating the validity of the methodology proposed. The results obtained considering three different theoretical initial sheet shapes indicate clearly that the methodology proposed is valid, as it provides solutions with physical meaning and with great potential to be applied in real practice. The different thickness profiles obtained for the optimal Pareto solutions show, in all cases, that that the different profiles along the front are related to the objectives considered. Also, there is a clear improvement in the successive generations of the evolutionary algorithm.This research was funded by NAWA-Narodowa Agencja Wymiany Akademickiej, under
grant PPN/ULM/2020/1/00125 and European Union’s Horizon 2020 research and innovation
programme under the Marie Skłodowska-Curie Grant Agreement No 734205–H2020-MSCA-RISE2016. The authors also acknowledge the funding by FEDER funds through the COMPETE 2020
Programme and National Funds through FCT (Portuguese Foundation for Science and Technology)
under the projects UID-B/05256/2020, UID-P/05256/2020, UIDB/00319/2020, MORPHING.TECH—
Direct digital Manufacturing of automatic programmable and Continuously adaptable patterned
surfaces with a discrete and patronized composition (POCI-01-0247-FEDER-033408)
Evidence for the naphthalene cation in a region of the interstellar medium with anomalous microwave emission
We report high resolution spectroscopy of the moderately reddened (A=3)
early type star Cernis 52 located in a region of the Perseus molecular cloud
complex with anomalous microwave emission. In addition to the presence of the
most common diffuse interstellar bands (DIBs) we detect two new interstellar or
circumstellar bands coincident to within 0.01% in wavelength with the two
strongest bands of the naphthalene cation (CH) as measured in
gas-phase laboratory spectroscopy at low temperatures and find marginal
evidence for the third strongest band.
Assuming these features are caused by the naphthalene cation, from the
measured intensity and available oscillator strengths we find that 0.008 % of
the carbon in the cloud could be in the form of this molecule. We expect
hydrogen additions to cause hydronaphthalene cations to be abundant in the
cloud and to contribute via electric dipole radiation to the anomalous
microwave emission. The identification of new interstellar features consistent
with transitions of the simplest polycyclic aromatic hydrocarbon adds support
to the hypothesis that this type of molecules are the carriers of both diffuse
interstellar bands and anomalous microwave emission.Comment: Accepted for publication in The Astrophysical Journa
Phloroglucinol is Effective for in vitro Growth and Multiplication of Musa accuminata Cv. Grand Naine Shoots and Roots
Despite being a major staple food in the world, banana production in the United States is still limited, with about 500 acres under cultivation. Micropropagation has been an effective method for the large-scale production of bananas to meet both domestic and international markets. However, the efficiency of micropropagation protocols depends on several factors, particularly on the types, combinations, and levels of plant growth regulators used in the culture media. Phloroglucinol is a growth regulator that acts synergistically with auxins and cytokinins. The use of phloroglucinol for the production and development of in vitro plantlets of Musa spp. cv. Grande Naine were investigated. Multiplication and elongation of shoots and roots in vitro was enhanced by the addition of 200 μM phloroglucinol to MS medium, as compared to the control with 13.2 μM BA. Higher concentrations (400 to 1000 μM phloroglucinol) resulted in reduced growth and development of shoots and roots in vitro
Publicações científicas eletrônicas no Brasil : mudanças na comunicação formal, também?
Results of an exploratory study which aimed to identify the occurrence of electronic publications (journals, books and conference proceedings) produced by academic institutions (universities and learned societies) in Brazil are presented. Relates, in the light of the recent literature, technology developments for electronic publishing, the issue of innovation adoption and the peer review process. Some comments on changes on the formal communication (publishing) as compared to impacts already perceived on the informal communication are presented, on the basis of a hybrid communication model that depicts the co-existence of the print and electronic media nowadays. The research data gathered in the study show that there is a low adoption of information technology in formal communication amongst academic researchers in Brazil. Most of the publications found constitute an electronic version of a print-on-paper one, and are from disciplines in the sciences. There has been a significant role played by Scielo in this process. Moreover, it seems that there has not been a fully exploitation of the technology already available to electronic publishing in the country so far. The peer review process, as it happens in the print-based communication model, is also an essential issue in this scenario.Apresenta resultados de um estudo exploratório que visou à identificação da ocorrência de publicações eletrônicas (periódicos, livros e anais de congressos) produzidas no âmbito de instituições acadêmicas (universidades e sociedades científicas) no Brasil. Discorre, de forma sucinta e com base na literatura recente, a respeito questões consideradas relevantes sobre desenvolvimentos da tecnologia de informação empregada em publicações eletrônicas, a questão da adoção de inovações e o processo de revisão pelos pares. Comenta as mudanças na comunicação formal (publicação) em comparação aos impactos já verificados na comunicação informal, à luz de um modelo híbrido do processo de comunicação que ilustra a coexistência dos meios impresso e eletrônico no cenário atual. Os resultados do estudo mostram baixa adoção das tecnologias de informação na comunicação formal entre pesquisadores acadêmicos no Brasil (poucas publicações produzidas). A maior parte das publicações disponibilizadas constituem versões eletrônicas de publicações impressas e ocorrem na área das ciências naturais, com uma significativa participação do Scielo nesse processo. Além disso, parece não haver ainda no país a exploração inteligente das tecnologias disponíveis para a produção de publicações eletrônicas, e o processo de revisão pelos pares, tal como se dá no modelo impresso, constitui igualmente questão fundamental nesse novo cenário
Hubble Space Telescope Imaging of the Optical Transient Associated with GRB970508
We report on Hubble Space Telescope (HST) observations of the optical
transient (OT) discovered in the error box of the gamma-ray burst GRB970508.
The object was imaged on 1997 June 2 with the Space Telescope Imaging
Spectrograph (STIS) and Near-Infrared Camera and Multi-Object Spectrometer
(NICMOS). The observations reveal a point-like source with R = 23.1 +- 0.2 and
H = 20.6 +- 0.3, in agreement with the power-law temporal decay seen in
ground-based monitoring. Unlike the case of GRB970228, no nebulosity is
detected surrounding the OT of GRB970508. We set very conservative upper limits
of R ~ 24.5 and H ~ 22.2 on the brightness of any underlying extended source.
If this subtends a substantial fraction of an arcsecond, then the R band limit
is ~25.5. In combination with Keck spectra that show Mg I absorption and [O II]
emission at a redshift of z = 0.835, our observations suggest that the OT is
located in a star-forming galaxy with total luminosity one order of magnitude
lower than the knee of the galaxy luminosity function, L*. Such galaxies are
now thought to harbor the majority of star formation at z ~ 1; therefore, these
observations may provide support for a link between GRBs and star formation.Comment: 12 pages, Latex, 2 Postscript figures, to appear in The Astrophysical
Journal Letter
A Produção de Hortaliças Orgânicas em Mercado não Tradicional: Um Estudo de Caso
This work aims to analyze the productive system of an organic vegetables grower in Ilha Solteira town, in the State of São Paulo. This case is distinguished by two important contexts: first, the most general, is that consumers seek better quality as to the food consumption. Although, in small towns, as Ilha Solteira, it does not exist adequacy in the retail establishments, and hence there isn't a clearly defined demand for organic products consumption. Secondly, it is highlighted the pioneering of the productive system in question, with emphasis to the lack of orientation either for local and regional production of organic goods (as in the places constituted by re-settlement and rural settlements as in the composition of regional agriculturalist offer) or for the consumption. The investigation concludes that, even the activities means the producer satisfaction, he has not taken advantage of the optimization from potential market opportunities, when he does not promote sales of his products tied for segments of targeted consumers who can buy them at better prices. Keywords: Family Agriculture; Organic Production; Rural Re-settlement.O trabalho objetiva analisar o sistema produtivo de um produtor de hortaliçasorgânicas na cidade de Ilha Solteira - SP. Este caso destaca-se por dois contextos importantes: um primeiro, mais geral, diz respeito à busca por parte dos consumidores, por melhor qualidade no consumo de alimentos. Apesar disto, em pequenas cidades, tais como Ilha Solteira, não existe adequação dos estabelecimentos varejistas e, portanto, demanda claramente definida para o consumo de produtos orgânicos. Em segundo lugar destaca-se o pioneirismo do sistema produtivo em questão, ressaltado pela inexistente orientação, tanto para o cultivo de produtos orgânicos local e regional (seja nos espaçosconstituídos de reassentamento e assentamentos rurais ou na composição da oferta agrícola regional) quanto para o consumo. O trabalho conclui que, embora sinalize satisfação com as atividades, o produtor não tem logrado otimizar as oportunidades potenciais de mercado, ao deixar de promover a comercialização de seus produtos junto a segmentos de consumidores que possam pagar melhores preços pelos mesmos
Propylthiouracil-induced cutaneous vasculitis
The use of propylthiouracil (PTU) is associated with the development of different auto-antibodies, amongst them are antineutrophil cytoplasmic antibodies (ANCA) that are involved in the pathogenesis of ANCA associated systemic vasculitis. The case of a 46-years old woman who presented cutaneous vasculitis when taking PTU for Graves' disease is reported. Perinuclear ANCA (p-ANCA) was positive with titer > 1/320, but anti-myeloperoxidase antibodies were not detected. Skin biopsy showed leucocytoclastic vasculitis. The patient improved within ten days after withdrawing PTU and the resolution of hyperthyroidism was achieved with radioiodine (131I). The p-ANCA test remained positive > 1/320 eight months and four years after PTU withdrawal.O uso do propiltiouracil (PTU) está associado ao desenvolvimento de diferentes auto-anticorpos, entre eles anticorpos anticitoplasma de neutrófilos (ANCA), que estão envolvidos na patogênese das vasculites sistêmicas ANCA-associadas (VSAA). Será relatado o caso de um paciente do sexo feminino, de 46 anos, que apresentou vasculite cutânea durante o uso de PTU como terapêutica para doença de Graves. O ANCA com padrão perinuclear (p-ANCA) foi positivo em títulos > 1/320, porém anticorpos antimielo-peroxidase (MPO) não foram detectados. A biópsia de pele revelou uma vasculite leucocitoclástica. Houve melhora clínica em dez dias após a retirada do PTU e optou-se pelo iodo radioativo (I131) para o tratamento do hipertireoidismo. O p-ANCA manteve-se positivo em títulos > 1/320 em duas medidas, realizadas oito meses e quatro anos após a suspensão do PTU.Hospital do Servidor Público Estadual Francisco Morato de OliveiraUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de MedicinaUNIFESP, EPMSciEL
A regional analysis of tide-surge interactions during extreme water levels in complex coastal systems of Aotearoa New Zealand
Tide-surge interaction (TSI) is a critical factor in assessing flooding in shallow coastal systems, particularly in estuaries and harbours. Non-linear interactions between tides and surges can occur due to the water depth and bed friction. Global investigations have been conducted to examine TSI, but its occurrence and impact on water levels in Aotearoa New Zealand (NZ) have not been extensively studied. Water level observations from 36 tide gauges across the diverse coast of NZ were analysed to determine the occurrence and location of TSI. Statistical analysis and numerical modelling were conducted on data from both inside and outside estuaries, focusing on one estuary (Manukau Harbour) to determine the impact of TSI and estuarine morphology on the co-occurrence rate of extreme events. TSI was found to occur at most sites in NZ and primarily affects the timing of the largest surges relative to high tide. There were no regional patterns associated with the tide, non-tidal residual, or skew-surge regimes. The strongest TSI occurred in inner estuarine locations and was correlated with the intertidal area. The magnitude of the TSI varied depending on the method used, ranging from -16 cm to +27 cm. Co-occurrence rates of extreme water levels outside and inside the same estuary varied from 20% to 84%, with TSI modulating the rate by affecting tidal amplification. The results highlight the importance of investing in a more extensive tide gauge network to provide longer observations in highly populated estuarine coastlines. The incorporation of TSI in flooding hazard projections would benefit from more accurate and detailed observations, particularly in estuaries with high morphological complexity. TSI occurs in most sites along the coast of NZ and has a significant impact on water levels in inner estuarine locations. TSI modulates the co-occurrence rate of extreme water levels in estuaries of NZ by affecting tidal amplification. Therefore, further investment in the tide gauge network is needed to provide more accurate observations to incorporate TSI in flooding hazard projections
The budget of carbon in the farming of the Amazon river prawn and tambaqui fish in earthen pond monoculture and integrated multitrophic systems
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