766 resultados para hybride value-added chain
Resumo:
Supermarkets and hypermarkets still represent a relatively new retailing format in Italy and in its Southern area in particular, where they were introduced decades later than in other Western countries, such as France and the UK in Europe, and the US in America. Nowadays, these retailers have become large organisations potentially capable of influencing local development from an economic, social and urban perspective. The literature concerned with their effects on the local economy, in particular, has focused on labour markets, price dynamics, inter-type competition, instead the impact on macroeconomic factors such as GDP, value added and investments in specific sectors, as agriculture, industry and services. This study tries to fill this gap by empirically investigating associations between key characteristics of these retailers and specific macroeconomic factors.
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Bioremediation implies the use of living organisms, primarily microorganisms, to convert environmental contaminants into less toxic forms. The impact of the consequences of hydrocarbon release in the environment maintain a high research interest in the study of microbial metabolisms associated with the biodegradation of aromatic and aliphatic hydrocarbons but also in the analysis of microbial enzymes that can convert petroleum substrates to value-added products. The studies described in this Thesis fall within the research field that directs the efforts into identifying gene/proteins involved in the catabolism of n-alkanes and into studying the regulatory mechanisms leading to their oxidation. In particular the studies were aimed at investigating the molecular aspects of the ability of Rhodococcus sp. BCP1 to grow on aliphatic hydrocarbons as sole carbon and energy sources. We studied the ability of Rhodococcus sp. BCP1 to grow on gaseous (C2-C4), liquid (C5-C16) and solid (C17-C28) n-alkanes that resulted to be biochemically correlated with the activity of one or more monooxygenases. In order to identify the alkane monooxygenase that is involved in the n-alkanes degradation pathway in Rhodococcus sp. BCP1, PCR-based methodology was applied by using degenerate primers targeting AlkB monooxygenase family members. As result, a chromosomal region, including the alkB gene cluster, was cloned from Rhodococcus sp. BCP1 genome. We characterized the products of this alkB gene cluster and the products of the orfs included in the flanking regions by comparative analysis with the homologues in the database. alkB gene expression studies were carried out by RT-PCR and by the construction of a promoter probe vector containing the lacZ gene downstream of the alkB promoter. B-galactosidase assays revealed the alkB promoter activity induced by n-alkanes and by n-alkanes metabolic products. Furthermore, the transcriptional start of alkB gene was determined by primer extension procedure. A proteomic approach was subsequently applied to compare the protein patterns expressed by BCP1 growing on n-butane, n-hexane, n-hexadecane or n-eicosane with the protein pattern expressed by BCP1 growing on succinate. The accumulation of enzymes specifically induced on n-alkanes was determined. These enzymes were identified by tandem mass spectrometry (LC/MS/MS). Finally, a prm gene, homologue to the gene family coding for soluble di-iron monooxygenases (SDIMOs), has been isolated from Rhodococcus sp. BCP1 genome. This gene product could be involved in the degradation of gaseous n-alkanes in this Rhodococcus strain. The versatility in utilizing hydrocarbons and the discovery of new remarkable metabolic activities outline the potential applications of this microorganism in environmental and industrial biotechnologies.
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The growing interest in environmental protection has led to the development of emerging biotechnologies for environmental remediation also introducing the biorefinery concept. This work mainly aimed to evaluate the applicability of innovative biotechnologies for environmental remediation and bioenergy production, throught fermentative processes. The investigated biotechnologies for waste and wastewater treatment and for the valorisation of specific feedstocks and energy recovery, were mainly focused on four research lines. 1. Biotechnology for textile wastewater treatment and water reuse that involving anaerobic and aerobic processes in combination with membrane technologies. Combinations of different treatments were also implemented for water reuse in a textile company. 2. Biotechnology for the treatment of solid waste and leachate in landfill and for biogas production. Landfill operated as Bioreactor with recirculation of the generated leachate was proposed for organic matter biostabilisation and for ammonia removal from leachate by favouring the Anammox process. 3. An innovative two-stage anaerobic process for effective codigestion of waste from the dairy industry, as cheese whey and dairy manure, was studied by combining conventional fermentative processes with a simplified system design for enhancing biomethanisation. 4) The valorisation of the glycerol waste as surplus by-product of the biodiesel industry was investigated via microbial conversion to value-added chemicals, as 1,3-propanediol. The investigated fermentative processes have been successfully implemented and reached high yields of the produced bio-chemical. The studied biotechnological systems proved to be feasible for environmental remediation and bioenergy and chemicals production.
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The advances that have been characterizing spatial econometrics in recent years are mostly theoretical and have not found an extensive empirical application yet. In this work we aim at supplying a review of the main tools of spatial econometrics and to show an empirical application for one of the most recently introduced estimators. Despite the numerous alternatives that the econometric theory provides for the treatment of spatial (and spatiotemporal) data, empirical analyses are still limited by the lack of availability of the correspondent routines in statistical and econometric software. Spatiotemporal modeling represents one of the most recent developments in spatial econometric theory and the finite sample properties of the estimators that have been proposed are currently being tested in the literature. We provide a comparison between some estimators (a quasi-maximum likelihood, QML, estimator and some GMM-type estimators) for a fixed effects dynamic panel data model under certain conditions, by means of a Monte Carlo simulation analysis. We focus on different settings, which are characterized either by fully stable or quasi-unit root series. We also investigate the extent of the bias that is caused by a non-spatial estimation of a model when the data are characterized by different degrees of spatial dependence. Finally, we provide an empirical application of a QML estimator for a time-space dynamic model which includes a temporal, a spatial and a spatiotemporal lag of the dependent variable. This is done by choosing a relevant and prolific field of analysis, in which spatial econometrics has only found limited space so far, in order to explore the value-added of considering the spatial dimension of the data. In particular, we study the determinants of cropland value in Midwestern U.S.A. in the years 1971-2009, by taking the present value model (PVM) as the theoretical framework of analysis.
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Il lavoro che presento propone un’analisi di una chiesa africana indipendente in Italia, la Celestial Church Of Christ Worldwide (CCCW), cercando di mettere in luce il nesso tra religione, migrazione e il processo di ‘plunting churches’ (Kooning 2009) nel contesto italiano. Attraverso una ricerca sul campo, sono stati indagati i percorsi personali, familiari e comunitari dei membri di una ‘Celestial Parish’ presente nel comune di Brescia, ‘Ileri Oluwa Parish’, al fine di comprendere la natura dei processi identitari coinvolti nell’organizzazione della CCC in Italia. ‘Ileri Oluwa Parish’, in quanto luogo che denota una ‘chiesa individuale collegata ad una Diocesi’ (CCC Constitution (CCC Constitution, 107 (d) si rivela, nella materialità delle sue forme e dei ‘Devotional Services’ che in essa si svolgono, a ‘field of action’ (Lefebvre, 1991). La storia della chiesa, i fondamenti della sua dottrina e i significati comunicati attraverso le forme rituali e religiose che la stessa promuove, sono stati contestualizzati alla luce delle tensioni e delle strategie di potere che strutturano il campo. Le storie dei membri della parrocchia, percorsi di migrazione e mobilità in itinere, rappresentano la lente attraverso cui si è guardato alle relazioni vissute nel nome dello ‘Spirito’, e alla percezione stessa di ciò che gli stessi Celestians definiscono sacro, santo, puro e impuro. Lo sguardo fisso alla vita ordinaria di una Celestial parish in Italia, esteso nell’ultima parte dell’elaborato alla Celestial parish londinese, è stato fondamentale per capire l’intreccio di relazioni spirituali, reti familiari e mobilità degli individui sul territorio italiano ed europeo, processo che ribalta la condizione diasporica della CCC, trasformando una condizione di dispersione in un valore aggiunto, nella possibilità di nuove traiettorie territoriali e spazi di presenza religiosa e socioeconomica.
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L'imposta sul valore aggiunto è caratterizzata da un meccanismo applicativo complesso preordinato al raggiungimento della neutralità in cui rivestono fondamentale rilevanza particolari obblighi strumentali richiesti al contribuente (fatturazione, registrazioni contabili, dichiarazioni). Il presente progetto di ricerca è finalizzato a valutare la propensione e funzionalità del meccanismo applicativo rispetto al generale principio di neutralità dell’imposta e la valenza svolta dagli obblighi strumentali rispetto alla qualificazione della fattispecie impositiva.
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The rise of new food assistance instruments, including local and regional procurement, cash, and vouchers, has surpassed increase in understanding of the tradeoffs among and impacts of these options relative to traditional food aid. Response choices rarely appear to result from systematic response analyses. Further, impacts along multiple dimensions-timeliness, cost-effectiveness, local market effects, recipient satisfaction, food quality, impact on smallholder suppliers, etc.-may be competing or synergistic. No single food assistance tool is always and everywhere preferable. A growing body of evidence, including the papers in this special section, nonetheless demonstrates the clear value-added of new food assistance instruments. (C) 2013 Elsevier Ltd. All rights reserved.
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In this review, we summarize the current "state of the art" of carbapenem antibiotics and their role in our antimicrobial armamentarium. Among the β-lactams currently available, carbapenems are unique because they are relatively resistant to hydrolysis by most β-lactamases, in some cases act as "slow substrates" or inhibitors of β-lactamases, and still target penicillin binding proteins. This "value-added feature" of inhibiting β-lactamases serves as a major rationale for expansion of this class of β-lactams. We describe the initial discovery and development of the carbapenem family of β-lactams. Of the early carbapenems evaluated, thienamycin demonstrated the greatest antimicrobial activity and became the parent compound for all subsequent carbapenems. To date, more than 80 compounds with mostly improved antimicrobial properties, compared to those of thienamycin, are described in the literature. We also highlight important features of the carbapenems that are presently in clinical use: imipenem-cilastatin, meropenem, ertapenem, doripenem, panipenem-betamipron, and biapenem. In closing, we emphasize some major challenges and urge the medicinal chemist to continue development of these versatile and potent compounds, as they have served us well for more than 3 decades.
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The research described in this dissertation is comprised of two major parts. The first part studied the effects of asymmetric amphiphilic end groups on the thermo-response of diblock copolymers of (oligo/di(ethylene glycol) methyl ether (meth)acrylates, OEGA/DEGMA) and the hybrid nanoparticles of these copolymers with a gold nanoparticle core. Placing the more hydrophilic end group on the more hydrophilic block significantly increased the cloud point compared to a similar copolymer composition with the end group placement reversed. For a given composition, the cloud point was shifted by as much as 28 °C depending on the placement of end groups. This is a much stronger effect than either changing the hydrophilic/hydrophobic block ratio or replacing the hydrophilic acrylate monomer with the equivalent methacrylate monomer. The temperature range of the coil-globule transition was also altered. Binding these diblock copolymers to a gold core decreased the cloud point by 5-15 °C and narrowed the temperature range of the coil-globule transition. The effects were more pronounced when the gold core was bound to the less hydrophilic block. Given the limited numbers of monomers that are approved safe for in vivo use, employing amphiphilic end group placement is a useful tool to tune a thermo-response without otherwise changing the copolymer composition. The second part of the dissertation investigated the production of value-added nanomaterials from two biorefinery “wastes”: lignin and peptidoglycan. Different solvents and spinning methods (melt-, wet-, and electro-spinning) were tested to make lignin/cellulose blended and carbonized fibers. Only electro-spinning yielded fibers having a small enough diameter for efficient carbonization ( Peptidoglycan (a bacterial cell wall material) was copolymerized with poly-(3-hydroxybutyrate), a common polyhydroxyalkanoate produced by bacteria with the objective of determining if a useful material could be obtained with a less rigorous work-up on harvesting polyhydroxyalkanoates. The copolyesteramide product having 25 wt.% peptidoglycan from a highly purified peptidoglycan increased thermal stability by 100-200 °C compared to the poly-(3-hydroxybutyrate) control, while a less pure peptidoglycan, harvested from B. megaterium (ATCC 11561), gave a 25-50 °C increase in thermal stability. Both copolymers absorbed more moisture than pure poly-(3-hydroxybutyrate). The results suggest that a less rigorously harvested and purified polyhydroxyalkanoate might be useful for some applications.
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In my Ph.D research, a wet chemistry-based organic solution phase reduction method was developed, and was successfully applied in the preparation of a series of advanced electro-catalysts, including 0-dimensional (0-D) Pt, Pd, Au, and Pd-Ni nanoparticles (NPs), 1-D Pt-Fe nanowires (NWs) and 2-D Pd-Fe nanoleaves (NLs), with controlled size, shape, and morphology. These nanostructured catalysts have demonstrated unique electro-catalytic functions towards electricity production and biorenewable alcohol conversion. The molecular oxygen reduction reaction (ORR) is a long-standing scientific issue for fuel cells due to its sluggish kinetics and the poor catalyst durability. The activity and durability of an electro-catalyst is strongly related with its composition and structure. Based on this point, Pt-Fe NWs with a diameter of 2 - 3 nm were accurately prepared. They have demonstrated a high durability in sulfuric acid due to its 1-D structure, as well as a high ORR activity attributed to its tuned electronic structure. By substituting Pt with Pd using a similar synthesis route, Pd-Fe NLs were prepared and demonstrated a higher ORR activity than Pt and Pd NPs catalysts in the alkaline electrolyte. Recently, biomass-derived alcohols have attracted enormous attention as promising fuels (to replace H2) for low-temperature fuel cells. From this point of view, Pd-Ni NPs were prepared and demonstrated a high electro-catalytic activity towards ethanol oxidation. Comparing to ethanol, the biodiesel waste glycerol is more promising due to its low price and high reactivity. Glycerol (and crude glycerol) was successfully applied as the fuel in an Au-anode anion-exchange membrane fuel cell (AEMFC). By replacing Au with a more active Pt catalyst, simultaneous generation of both high power-density electricity and value-added chemicals (glycerate, tartronate, and mesoxalate) from glycerol was achieved in an AEMFC. To investigate the production of valuable chemicals from glycerol electro-oxidation, two anion-exchange membrane electro-catalytic reactors were designed. The research shows that the electro-oxidation product distribution is strongly dependent on the anode applied potential. Reaction pathways for the electro-oxidation of glycerol on Au/C catalyst have been elucidated: continuous oxidation of OH groups (to produce tartronate and mesoxalate) is predominant at lower potentials, while C-C cleavage (to produce glycolate) is the dominant reaction path at higher potentials.
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This Ph.D. research is comprised of three major components; (i) Characterization study to analyze the composition of defatted corn syrup (DCS) from a dry corn mill facility (ii) Hydrolysis experiments to optimize the production of fermentable sugars and amino acid platform using DCS and (iii) Sustainability analyses. Analyses of DCS included total solids, ash content, total protein, amino acids, inorganic elements, starch, total carbohydrates, lignin, organic acids, glycerol, and presence of functional groups. Total solids content was 37.4% (± 0.4%) by weight, and the mass balance closure was 101%. Total carbohydrates [27% (± 5%) wt.] comprised of starch (5.6%), soluble monomer carbohydrates (12%) and non-starch carbohydrates (10%). Hemicellulose components (structural and non-structural) were; xylan (6%), xylose (1%), mannan (1%), mannose (0.4%), arabinan (1%), arabinose (0.4%), galatactan (3%) and galactose (0.4%). Based on the measured physical and chemical components, bio-chemical conversion route and subsequent fermentation to value added products was identified as promising. DCS has potential to serve as an important fermentation feedstock for bio-based chemicals production. In the sugar hydrolysis experiments, reaction parameters such as acid concentration and retention time were analyzed to determine the optimal conditions to maximize monomer sugar yields while keeping the inhibitors at minimum. Total fermentable sugars produced can reach approximately 86% of theoretical yield when subjected to dilute acid pretreatment (DAP). DAP followed by subsequent enzymatic hydrolysis was most effective for 0 wt% acid hydrolysate samples and least efficient towards 1 and 2 wt% acid hydrolysate samples. The best hydrolysis scheme DCS from an industry's point of view is standalone 60 minutes dilute acid hydrolysis at 2 wt% acid concentration. The combined effect of hydrolysis reaction time, temperature and ratio of enzyme to substrate ratio to develop hydrolysis process that optimizes the production of amino acids in DCS were studied. Four key hydrolysis pathways were investigated for the production of amino acids using DCS. The first hydrolysis pathway is the amino acid analysis using DAP. The second pathway is DAP of DCS followed by protein hydrolysis using proteases [Trypsin, Pronase E (Streptomyces griseus) and Protex 6L]. The third hydrolysis pathway investigated a standalone experiment using proteases (Trypsin, Pronase E, Protex 6L, and Alcalase) on the DCS without any pretreatment. The final pathway investigated the use of Accellerase 1500® and Protex 6L to simultaneously produce fermentable sugars and amino acids over a 24 hour hydrolysis reaction time. The 3 key objectives of the techno-economic analysis component of this PhD research included; (i) Development of a process design for the production of both the sugar and amino acid platforms with DAP using DCS (ii) A preliminary cost analysis to estimate the initial capital cost and operating cost of this facility (iii) A greenhouse gas analysis to understand the environmental impact of this facility. Using Aspen Plus®, a conceptual process design has been constructed. Finally, both Aspen Plus Economic Analyzer® and Simapro® sofware were employed to conduct the cost analysis as well as the carbon footprint emissions of this process facility respectively. Another section of my PhD research work focused on the life cycle assessment (LCA) of commonly used dairy feeds in the U.S. Greenhouse gas (GHG) emissions analysis was conducted for cultivation, harvesting, and production of common dairy feeds used for the production of dairy milk in the U.S. The goal was to determine the carbon footprint [grams CO2 equivalents (gCO2e)/kg of dry feed] in the U.S. on a regional basis, identify key inputs, and make recommendations for emissions reduction. The final section of my Ph.D. research work was an LCA of a single dairy feed mill located in Michigan, USA. The primary goal was to conduct a preliminary assessment of dairy feed mill operations and ultimately determine the GHG emissions for 1 kilogram of milled dairy feed.
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Die generativen Fertigungsverfahren haben längst ihren Platz in der Wertschöpfungskette neben konventionellen Prozessen eingenommen. Trotzdem müssen die Anwender immer wieder aufs Neue für die recht abstrakten Möglichkeiten und Chancen der Verfahren sensibilisiert werden. Querdenken kann oft schneller und effizienter zur erfolgreichen Problemlösung beitragen als traditionelle Schlüsselwege. Deshalb soll der Beitrag einige Kernpunkte ansprechen, die die additiven Verfahren in den Unternahmen – speziell das LaserCUSING® - als überaus sinnvolle Ergänzung des Technologieparks erachten. Neben der Herstellung von metallischen Prototypen geht der Vortrag insbesondere auf die Vielfalt der Effekte integrierbarer Kanäle in Formeinsätzen besonders des Spritzgusswerkzeugbaus ein.
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Stets darauf bedacht, die Anlagen- und Maschinenverfügbarkeit bei möglichst geringem Ressourceneinsatz zu gewährleisten, wird die Rolle der Instandhaltung als unternehmerischer Wertschöpfungsfaktor immer bedeutsamer. Voraussetzung für eine Nutzbarmachung bestehender Potentiale sind neue Werkzeuge und Ansätze, deren Umsetzung eine effiziente Sicherstellung von Verfügbarkeit ermöglicht. Vor diesem Hintergrund wurde im Teilprojekt C3 des DFG Paketantrags 672 ein Konzept zur nutzungsabhängigen Instandhaltung entwickelt. Auf Grundlage des bestehenden Zusammenhangs von Nutzung und Abnutzung risikobehafteter Bauteile intralogistischer Systeme können damit die durch zukünftige Systemlasten hervorgerufenen Beanspruchungen antizipiert werden. Instandhaltungsmaßnahmen und technische Verfügbarkeiten werden dadurch anforderungsgerecht und ressourcen-optimal planbar.
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This paper asks how takeover and failure hazards change as listed firms get older. The hypothesis is that they increase because firms gradually run out of growth opportunities. We find the opposite. Both takeover and failure hazard drop significantly with age. The decline in takeover hazard can be explained with Loderer, Stulz, and Waelchli’s (2013) “buggy whip makers” hypothesis: Because old firms are comparatively well-managed and are affected by limited agency problems, on average, they offer little value added potential to acquirers. Failure hazard drops because to learning. The results are robust to various alternative interpretations and cannot be explained by unobserved heterogeneity. While hazards decline with age, they do not go to zero. This explains why, eventually, all listed firms disappear
Resumo:
This paper asks how takeover and failure hazards change as listed firms get older. The hypothesis is that they increase because firms gradually run out of growth opportunities. We find the opposite. Both takeover and failure hazard drop significantly with age. The decline in takeover hazard can be explained with Loderer, Stulz, and Waelchli’s (2013) “buggy whip makers” hypothesis: Because old firms are comparatively well-managed and are affected by limited agency problems, on average, they offer little value added potential to acquirers. Failure hazard drops because to learning. The results are robust to various alternative interpretations and cannot be explained by unobserved heterogeneity. While hazards decline with age, they do not go to zero. This explains why, eventually, all listed firms disappear