923 resultados para chemical technology and engineering


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Case histories of large, accidental fires are presented to illustrate that heavy metals may be used as markers to assess the extent of localized environmental contamination resulting from fires. Due to the complexity of fire chemistry with respect to organic pollutants, determination of organic pollutants in the environment following a fire would be time consuming and expensive. Using heavy metals as markers on the other hand is much cheaper and can be done very rapidly. © 1995.

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(abreviated) We aim to study the inner-wind structure (R<250 Rstar) of the well-known red supergiant VY CMa. We analyse high spatial resolution (~0".24x0".13) ALMA Science Verification (SV) data in band 7 in which four thermal emission lines of gaseous sodium chloride (NaCl) are present at high signal-to-noise ratio. For the first time, the NaCl emission in the inner wind region of VY CMa is spatially resolved. The ALMA observations reveal the contribution of up to four different spatial regions. The NaCl emission pattern is different compared to the dust continuum and TiO2 emission already analysed from the ALMA SV data. The emission can be reconciled with an axisymmetric geometry, where the lower density polar/rotation axis has a position angle of ~50 degrees measured from north to east. However, this picture can not capture the full morphological diversity, and discrete mass ejection events need to be invoked to explain localized higher-density regions. The velocity traced by the gaseous NaCl line profiles is significantly lower than the average wind terminal velocity, and much slower than some of the fastest mass ejections, signalling a wide range of characteristic speeds for the mass loss. Gaseous NaCl is detected far beyond the main dust condensation region. Realising the refractory nature of this metal halide, this hints at a chemical process preventing all NaCl from condensing onto dust grains. We show that in the case of the ratio of the surface binding temperature to the grain temperature being ~50, only some 10% of NaCl remains in gaseous form, while for lower values of this ratio thermal desorption efficiently evaporates NaCl. Photodesorption by stellar photons seems not to be a viable explanation for the detection of gaseous NaCl at 220 Rstar from the central star, and instead, we propose shock-induced sputtering driven by localized mass ejection events as alternative.

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Lavandula spp. belong to the family Lamiatae and some species are often used in popular medicine and have been used for centuries in a large number of medical applications and in aromatherapy. Although similar ethnobotanical properties of Lavandula spp., its essential oils, general chemical composition and therapeutic applications differ from different species. Lavandula stoechas L. subsps. luisieri (Rozeira) Rozeira and L. viridis L’Hér are endemic to the Iberian Peninsula, widespread in the South of Portugal, namely in Southern Alentejo and Algarve. The aim of our study was evaluate the chemical composition and toxicological and pharmacological activities of leaves essential oils of spontaneous plants of L. stoechas L. subsps. luisieri (Alentejo) and L. viridis (Algarve). The essential oils of these wild plants, collected in spring, were obtained by hydrodistillation in a Clevenger-type apparatus and its chemical composition was evaluated by GC/FID. The acute toxicity of essential oils was evaluated "in vitro" using brine shrimp (LC50) and "in vivo" using Swiss mice (DL50). The analgesic and anti-inflammatory pharmacological properties of L. stoechas subsp. luisieri essential oil were evaluated in mouse or rats by the Amour-Smith and carrageen-induced paw edema tests, respectively. Results showed important differences in chemical composition of essential oils from two species analyzed either to diversity and proportion of its constituents. The essentials oils showed citotoxicity against Artemia salina and a DL50 higher than 2000 mg/kg for mice. The analgesic and anti-inflammatory activities of essential oils were exhibit for the doses of 100 and 200 mg/kg.

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Lavenders belong to the family Labiatae and represent some of the most popular medicinal plants of great economic importance. Their essential oils are important for the perfume, cosmetic, flavouring and pharmaceutical industries. However, despite its popularity, and the long tradition of use, biological properties of the various Lavandula species are not yet been well sustained by scientific or clinical studies and some available data being inconclusive and controversial [1]. Although Lavandula spp. have similar ethnobotanical properties, however, chemical composition and therapeutic uses differ from different species and main composition of essential oils showed differences with species and with the region were they grow [1,2,3]. L. stoechas L. subsps. luisieri (Rozeira) Rozeira. L. pedunculata (Mill.) Cav. and L. viridis L’Hér are endemic to the Iberian Peninsula, widespread in the South of Portugal, namely in Alentejo and Algarve. In our work, essential oils from the stems or leaves from wild grown plants of L. luisieri (Alentejo), L. pedunculata (Alentejo) and L. viridis (Algarve), were extracted by hydrodistillation and analyzed by GC-FID. Antimicrobial activity was evaluated by solid diffusion disk assay and minimal inhibitory concentration (MIC) against pathogenic Gram-positive and Gram-negative bacteria and food spoilage fungi.

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Effect of storage on physical-chemical properties and phenolics of sweet cherry from São Julião region. A.C. Agulheiro-Santos1, F. Vieira1, D. Gonzalez2, M. Lozano2, V. Palma1, A.E. Rato1 1Universidade de Évora. Instituto de Ciências Agrárias e Ambientais Mediterrânica (ICAAM). 7000 Évora, Portugal. 2Centro de Investigaciones Científicas y Tecnológicas de Extremadura (CICYTEX). Ctra. San Vicente. Finca Santa Engracia. 06071 Badajoz, Spain. Worldwide the consumption of fruit and vegetables is increasing due to the dietary guidelines recommended by nutritionist. Because of their high content on phenols, vitamins, mineral and antioxidants, berry fruits are consumed not only in fresh forms but also as processed and derivative products such as juices, yogurts, jellies and dried fruits. As a high consumed red fruit, sweet cherry has been the focus on some studies, mainly regarding bioactive compounds content. “Sweetheart” cherries from São Julião region (Alentejo, Portugal) from two different production campaigns were kept in different storage conditions in order to evaluate both the environmental and storage effect on some physical-chemical properties and phenolics. Cold conditions - Cold (1 ºC, 95% RH) and modified atmosphere - MA (1 ºC, 95% RH with micro-perforated bags of Pplus®, Sidlaw Packaging, Bristol, UK) were tested. In order to establish the appropriate storage conditions, individual phenolic acids and physical-chemical properties were analysed during two consecutive years. Results show a general decrease on phenolic compounds content between cherries from both years. It is also observed that MA conditions do not affect significantly both phenolics and physical-chemical parameters when compared with Cold conditions. Additionally, it is observed similar behaviour on Cold and MA sweet cherries regarding its pH, total soluble solids content (TSS), titratable acidity (TA) and colour and individual phenols during storage time. Concluding, these results show, as expected, changes between cultivars which may be correlated with the environmental conditions on different years. Keywords: sweet cherry, postharvest, phenols, physical-chemical, storage conditions.

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This co-written chapter was included in an edited book featuring invited authors from different countries and different areas of museum research and practice. The chapter uses a theory of play by Johan Huizinga (1938) to frame case studies of play-based interactive experiences in museums in various countries. The aim was to use theory to ground museum practice, in order to evaluate existing practical implementations as well as to inform the design of new ones. The book was nominated as one of the 10 best museum education books of 2011 by Museum Education Monitor, and the chapter led to a subsequent technology residency the author undertook in the Spike Island gallery, Bristol in 2012, funded by the National Endowment for Science, Technology and the Arts, Arts and Humanities Research Council and Arts Council England. It also informed his subsequent postgraduate teaching, an example of which is a recent MA project, which deconstructs play from a computational perspective. Collaborations have continued with the co-author, which have resulted in a number of invited lectures. In this chapter the authors explore play as a structure for supporting visitor learning, drawing from international research in museums and interaction design. Four aspects of play first proposed by Huizinga are explored – the free-choice aspect of play, play as distinct from real life, play as an ordering structure, and the role of play in bridging communities. The chapter argues that play provides museums with ready-made structures and concepts, which can help planning for visitor learning. The research was equally divided between the co-authors, who developed the conceptual and theoretical aspects of the article by drawing on their own research alongside key examples of museum design and digital media.

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The career destiny of many graduate engineers is in industry. Quite how well prepared they were for that career became a matter of political importance in the late 1950s and early 1960s as the issue of Britain's relatively poor economic performance grew in salience. This article looks at this preparation with particular reference to management training. It examines the attitudes of those parties most interested in engineering education ‐ the government, industry, the engineering institutions and the educators themselves. All of these saw management training as being part of the formation of at least a portion of professional engineers at some stage in their career. But there was no general agreement between them about what this should consist of or when it should be provided. At the same time broader changes in engineering education were taking place which cut across and to some extent militated against attempts to enhance the role of management training. The result, it is argued, is that by the end of the 1960s little progress had been achieved.

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The study examines the relationship between law, technology and water conflicts from colonial days to the present in traditional (water) tank systems in the south Indian state of Tamil Nadu. Tanks are man-made water systems developed for irrigation and many other purposes in semi-arid areas. The thesis adopts a historical approach to study the development of law, particularly property rights, and takes an empirical approach to investigate the tank conflicts. Archival documents on irrigation development, Case laws, Focus Group Discussions, Open ended Interviews and Field visits to selected tank chains are used as source material for the discussion. Case studies of conflicts are described and analyzed at three levels - Vaigai river basin for a macro level, Kothai Anicut system in Cauvery basin for a meso level, and twenty other interconnected tanks for a micro-level. The thesis deviates from the conventional understanding that tanks as traditional systems as simple and local technologies but considers them to be complex. It argues that the use of commonly held systems such as tanks within the colonial and post colonial laws as state ownership has been the source of many conflicts. In particular, it finds most tank conflicts are a product of progressive and absolute state control over water and the systems established using colonial land revenue administrative law. The law continues to treat tanks as pieces of landed property held by state and the individuals rather than as technology systems that presupposed the regime of property rights introduced after the colonial times. The modern interventions in water including the reservoir building, and altering the hydraulics of rivers and streams aggravate tank conflicts and lead to their further detriment. The study brings the focus to ground realities, and offers new perspectives on understanding tank systems in dynamic ways.

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Trabalho de Projeto apresentado como requisito parcial para obtenção do grau de Mestre em Estatística e Gestão de Informação

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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

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This work project focuses on developing new approaches which enhance Portuguese exports towards a defined German industry sector within the information technology and electronics fields. Firstly and foremost, information was collected and a set of expert and top managers’ interviews were performed in order to acknowledge the demand of the German market while identifying compatible Portuguese supply capabilities. Among the main findings, Industry 4.0 presents itself as a valuable opportunity in the German market for Portuguese medium sized companies in the embedded systems area of expertise for machinery and equipment companies. In order to achieve the purpose of the work project, an embedded systems platform targeting machinery and equipment companies was suggested as well as it was developed several recommendations on how to implement it. An alternative approach for this platform was also considered within the German market namely the eHealth sector having the purpose of enhancing the current healthcare service provision.

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Forty-five 12- and 13-year-old females attending Grade 7 in North York, Ontario were randomly selected from a group of 100 females who had volunteered to participate in a oneday hands-on workshop called It's Your Choice at Seneca College. The goals of this intervention were to broaden the career horizons of these students and to help them realize the need to continue mathematics and science through high school in order to keep occupational options unlimited. The young women were given a pre- and post-attitude survey to provide background information. In the month following participation in the workshop the students were interviewed in small groups (S students per group) to discover their perceptions of the impact of the workshop. The interviews revealed that participants felt that after the workshop their feelings of self-confidence increased, specifically with respect to working with their hands. Participants felt more aware of the usefulness and importance of the study of mathematics, science and technology, They also felt that It's Your Choice increased their interest in careers in these domains and helped them to see that these careers are viable choices for females. The interviews also revealed that many of the participants felt that in this society their roles and their choices were influenced and probably limited by the fact that they are female.

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Photosynthetic state transitions were investigated in the cyanobacterium Synechococcus sp. PCC 6301 by studying fluorescence emission, heat loss, and PS I activity in intact cells brought to state 1 and state 2. 77K fluorescence emission spectra were modelled with a sum of 6 components corresponding to PBS, PS II, and PS I emissions. The modelled data showed a large decrease in PS II fluorescence accompanied with a small increase in the PS I fluorescence upon transition to state 2 for excitation wavelengths absorbed by both PBS and ChI ll.. The fluorescence changes seen with ChI .a. excitations do not support the predictions of the mobile PBS model of state transition in PBS-containing organisms. Measurements of heat loss from intact cells in the two states were similar for both ChI it. and PBS excitations over three orders of magnitude of laser flash intensity. This suggests that the PBS does not become decoupled from PS II in state 2 as proposed by the PBS detachment model of state transition in PBS-containing organisms. PS I activity measurements done on intact cells showed no difference in the two states, in contrast with the predictions of all of the existing models of state transitions. Based on these results a model for state transition In PBScontaining organisms is proposed, with a PS II photoprotectory function.

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Metal Music as Critical Dystopia: Humans, Technology and the Future in 1990s Science Fiction Metal seeks to demonstrate that the dystopian elements in metal music are not merely or necessarily a sonic celebration of disaster. Rather, metal music's fascination with dystopian imagery is often critical in intent, borrowing themes and imagery from other literary and cinematic traditions in an effort to express a form of social commentary. The artists and musical works examined in this thesis maintain strong ties with the science fiction genre, in particular, and tum to science fiction conventions in order to examine the long-term implications of humanity's complex relationship with advanced technology. Situating metal's engagements with science fiction in relation to a broader practice of blending science fiction and popular music and to the technophobic tradition in writing and film, this thesis analyzes the works of two science fiction metal bands, VOlvod and Fear Factory, and provides close readings of four futuristic albums from the mid to late 1990s that address humanity's relationship with advanced technology in musical and visual imagery as well as lyrics. These recorded texts, described here as cyber metal for their preoccupation with technology in subject matter and in sound, represent prime examples of the critical dystopia in metal music. While these albums identify contemporary problems as the root bf devastation yet to come, their musical narratives leave room for the possibility of hope , allowing for the chance that dystopia is not our inevitable future.