968 resultados para green synthesis
Resumo:
The Subtropical Design Handbook for Planners is primarily intended to provide advice in developing planning schemes to achieve the South East Queensland Regional Plan’s vision. This calls for ‘development which is sustainable and well-designed, and where the subtropical character of the region is recognised and reinforced’.
Resumo:
Primary aminoporphyrin, secondary bis(porphyrinyl)amine and hydroxyporphyrin complexes have been isolated and characterised both spectroscopically and crystallographically from the reaction of 5-bromo-10,15,20-triphenylporphyrinato-nickel(II) with hydrazine under palladium catalysis.
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Lithium niobate powders from the raw powders of Li2 O5 are directly synthesized by a combustion method with urea fuel. The synthesis parameters (e.g. the calcination temperature, calcination time, and urea-to-(Li2 CO3 + Nb2 O5) quantity ratio) are studied to reveal the optimized synthesis conditions for preparing high-quality lithium niobate powders. In our present work, it is found that a urea-to-(Li2 CO3 + Nb2 O5) ratio close to 3, calcination temperature at 550-600 degrees and reaction time around 2.5h may lead to high-quality lithium niobate powsers. The microstructure of synthesized powders is further studied; a possible mechanism of the involved reactions is also proposed.
Resumo:
A combustion synthesis of lithium niobate (LN) squares from activated niobium oxide (Nb2 O5.nH2O) and Li2CO3 was studied to understand all the chemical reactions involved, and the nucleation and square-growth mechanisms. It was found that first the lithium ions react with the fuel (urea), then niobium ions of Nb2 O5.nH2O begin a continuous reaction with the fuel to form metal-organic complexes. LN nuclei are formed by the solid-state reaction of Li- and Nb-organic complexes at 430 degrees celcius. Lithium niobate squares are obtained in the crystallization stasge at 700 degrees celcius, which go on the grow into larger squares at 850 degrees celcius because of the agglomeration effect.
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Raman spectroscopy has been used to characterise nine hydrotalcites prepared from aluminate and magnesium solutions (magnesium chloride and seawater). The aluminate hydrotalcites are proposed to have the following formula Mg6Al2(OH)16(CO32-).xH2O, Mg6Al2(OH)16(CO32-,SO42-).xH2O, and Mg6Al2(OH)16(SO42-).xH2O. The synthesis of these hydrotalcites using seawater results in the intercalation of sulfate anions into the hydrotalcite interlayer. The spectra have been used to assess the molecular assembly of the cations and anions in the hydrotalcite structures. The spectra have been conveniently subdivided into spectral features based upon the carbonate anion, the hydroxyl units and water units. This investigation has shown the ideal conditions to form hydrotalcite from aluminate solutions is at pH 14 using magnesium chloride. Changes in synthesis conditions resulted in the formation of impurity products aragonite, thenardite, and gypsum.
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Near infrared (NIR), infrared (IR) spectroscopy and X-ray diffraction (XRD) have been applied to halotrichites of the formula FeAl2(SO4)4∙22H2O and Fe2+Fe23+(SO4)4∙22H2O. Comparison of the halotrichites and their starting materials has been used to give a better understanding of the bonding involved in these types of minerals. The vibrational spectroscopy data has shown that Fe2+ oxidises during the formation of halotrichite, no preventative measures were implemented to prevent oxidation, and this has been clearly shown by the position and broadness of electronic bands of transition metals in the NIR spectra (12500 to 7500 cm-1). It is apparent from this region that Fe3+ substitutes for Al3+ in the synthesis of halotrichite. Due to the oxidation of Fe2+ to Fe3+ the halotrichite sample contains a small portion of bilinite. This has been confirmed by XRD, peaks at 9 and 14° 2θ were observed in the halotrichite sample and are identical to the XRD pattern obtained for bilinite. Substitution of aluminium for Fe3+ has resulted in significant changes in the overall infrared and NIR spectral profiles. However, the lower wavenumber regions of the NIR spectra have very similar spectral profiles, which indicate a similar structure to halotrichite has formed for bilinite. This work has shown that iron halotrichites can be synthesised and characterised by infrared and NIR spectroscopy.
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Sustainable practices are more than ever on the radar screen of organizations, triggered by a growing demand of the wider population towards approaches and practices that can be considered "green" or "sustainable". Our specific intent with this call for action is to immerse deeper into the role of business processes, and specifically the contributions that the management of these processes can play in leveraging the transformative power of information systems (IS) in order to create environmentally sustainable organizations. Our key premise is that business and information technology (IT) managers need to engage in a process-focused discussion to enable a common, comprehensive understanding of process, and the process-centered opportunities for making these processes, and ultimately the organization as a process-centric entity, "green". Based on a business process lifecycle model, we propose possible avenues for future research.
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Objective: To quantify the levels of proteoglycan 4 (PRG4) expression by subpopulations of chondrocytes from superficial, middle, and deep layers of normal bovine calf cartilage in various culture systems. Methods: Bovine calf articular cartilage discs or isolated cells were used in I of 3 systems of chondrocyte culture: explant, monolayer, or transplant, for 1-9 days. PRG4 expression was quantified by enzyme-linked immunosorbent assay of spent medium and localized by immunohistochemistry at the articular surface and within chondrocytes in explants and cultured cells. Results: Superficial chondrocytes secreted much more PRG4 than did middle and deep chondrocytes in all cultures. The pattern of PRG4 secretion into superficial culture medium varied with the duration of culture, decreasing with time in explant culture (from similar to25 mug/cm(2)/day on days 0-1 to similar to3 mug/cm(2)/day on days 5-9), while increasing in monolayer culture (from similar to1 pg/cell/day on days 0-1 to similar to7 pg/cell/day on days 7-9) and tending to increase in transplant culture (reaching similar to2 mug/cm(2)/day by days 7-9). In all of the culture systems, inclusion of ascorbic acid stimulated PRG4 secretion, and the source of PRG4 was immunolocalized to superficial cells. Conclusion: The results described here indicate that the phenotype of PRG4 secretion by chondrocytes in culture is generally maintained, in that PRG4 is expressed to a much greater degree by chondrocytes from the superficial zone than by those from the middle and deep zones. The marked up-regulation of PRG4 synthesis by ascorbic acid may have implications for cartilage homeostasis and prevention of osteoarthritic disease. Transplanting specialized cells that secrete PRG4 to a surface may impart functional lubrication and be generally applicable to many tissues in the body.
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We have successfully synthesized hydrotalcites (HTs) contg. calcium, which are naturally occurring minerals. Insight into the unique structure of HTs has been obtained using a combination of X-ray diffraction (XRD) as well as IR and Raman spectroscopies. Calcium-contg. hydrotalcites (Ca-HTs) of the formula Ca4Al2(CO3)(OH)12·4H2O (2:1 Ca-HT) to Ca8Al2(CO3)(OH)20· 4H2O (4:1 Ca-HT) have been successfully synthesized and characterised by XRD and Raman spectroscopy. XRD has shown that 3:1 calcium HTs have the largest interlayer distance. Raman spectroscopy complemented with selected IR data has been used to characterize the synthesized Ca-HTs. The Raman bands obsd. at around 1086 and 1077 cm-1 were attributed to the ν1 sym. stretching modes of the (CO32-) units of calcite and carbonate intercalated into the HT interlayer. The corresponding ν3 CO32- antisym. stretching modes are found at around 1410 and 1475 cm-1.
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The seawater neutralisation process is currently used in the Alumina industry to reduce the pH and dissolved metal concentrations in bauxite refinery residues, through the precipitation of Mg, Al, and Ca hydroxide and carbonate minerals. This neutralisation method is very similar to the co-precipitation method used to synthesise hydrotalcite (Mg6Al2(OH)16CO3•4H2O). This study looks at the effect of temperature on the type of precipitates that form from the seawater neutralisation process of Bayer liquor. The Bayer precipitates have been characterised by a variety of techniques, including X-ray diffraction, Raman spectroscopy and infrared spectroscopy. The mineralogical composition of Bayer precipitates largely includes hydrotalcite, hydromagnesite, and calcium carbonate species. XRD determined that Bayer hydrotalcites that are synthesised at 55 °C have a larger interlayer distance, indicating more anions are removed from Bayer liquor. Vibrational spectroscopic techniques have identified an increase in hydrogen bond strength for precipitates formed at 55 °C, suggesting the formation of a more stable Bayer hydrotalcite. Raman spectroscopy identified the intercalation of sulfate and carbonate anions into Bayer hydrotalcites using these synthesis conditions.
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I am sure you’ve heard it too: Green is the new Black. While this was true back in the days when Henry Ford introduced process standardization with his assembly line for the Ford Model T (over 15 million of these were sold!), Green is also the color of choice for many business organizations, private and public. I am not talking about the actual color of their business shirts or their logo 2.0.; I am referring to the eco-aware movement that has pushed sustainability into the top ten list of business buzz-words. What used to be a boutique market for tourism and political activists has become the biggest business revolution since the e-commerce boom. Public and private organizations alike push towards “sustainable” solutions and practices. That push is partly triggered by the immense reputational gains associated with branding your organization as “green”, and partly by emerging societal, legal and constitutional regulations that force organizations to become more ecologically aware and sustainable. But the boom goes beyond organizational reality. Even in academia, sustainability has become a research “fashion wave” (see [1] if you are interested in research fashion waves) similar to the hype around Neuroscience that our colleagues in the natural sciences are witnessing these days. Mind you, I’m a fan. A big fan in fact. As academics, we are constantly searching for problem areas that are characterized by an opportunity to do rigorous research (studies that are executed to perfection) on relevant topics (studies that have applied practical value and provide impact to the community). What would be a better playground than exploring the options that Business Process Management provides for creating a sustainable, green future? I’m getting excited just writing about this! So, join me in exploring some of the current thoughts around how BPM can contribute to the sustainability fashion parade and let me introduce you to some of the works that scholars have produced recently in their attempts to identify solutions.
Resumo:
Despite the ongoing debate surrounding climate change, sustainability is increasingly a key consideration for building owners and tenants with the ‘triple bottom line’ as desired outcomes. The triangulated social, economic and environmental goals of sustainability are now the mantra of many businesses. While much has been written of the benefits of green buildings to its occupants, comparatively fewer studies have been devoted to investigating the perceived drawbacks and measures to improve the social sustainability factor, i.e., user satisfaction. Therefore, the purpose of this paper is to consider the impacts of green buildings on its occupants by drawing together past empirical findings and summarizing the results. In addition, the paper will also present a case study of the Institute of Sustainable Development and Architecture, which is Australia’s first 6-green star, rated educational building. Through these methods, the paper will identify gaps between green building performance and user satisfaction. Thereafter, it will introduce a social sustainability framework that seeks to improve the social performance of green buildings. The 6-P model is a holistic framework targeting the following factors that can influence user satisfaction of green buildings. These factors are: public perception, price, policies, psychological, physical and personal.