On-line monitoring of the transesterification reaction carried out in microreactors using near infrared spectroscopy

Biodiesel can be produced from vegetable oils, animal fats, and waste cooking oils by transesterification with ethanol (also called ethanolysis) in order to substitute fossil fuels. In this work, the batch ethanolysis of high oleic sunflower oil was transferred into a continuous microstructured device, which induces a better control of heat and mass transfers. Various parameters were studied, notably the initial ethanol to oil molar ratio. An innovative method using NIR spectroscopy was also developed to on-line monitor the transesterification reaction of high oleic sunflower oil with ethanol in microreactors (circular PFA tube 1/1600 OD, 0.0200 ID). The reactions were monitored directly in the microreactors through sequential scans of the reaction medium by the means of an adequate probe. The asset of the method is that no sample collection or preparation is necessary. Partial Least Squares regression was used to develop calibration and prediction models between NIR spectral data and analytical data obtained by a reference method (gas chromatography with flame ionization detection, GC–FID). This method is fast, safe, reliable, nondestructive and inexpensive contrary to conventional procedures, such as gas chromatography and high performance liquid chromatography generally used to determine the composition of crude transesterification medium

On-line monitoring of the transesterification reaction between triglycerides and ethanol using near infrared spectroscopy combined with gas chromatography

Many analytical procedures have been developed to determine the composition of reaction mixtures during transesterification of vegetable oils with alcohols. However, despite their accuracy, these methods are time consuming and cannot be easily used for on-line monitoring. In this work, a fast analytical method was developed to on-line monitor the transesterification reaction of high oleic sunflower oil with ethanol using Near InfraRed spectroscopy and a multivariate approach. The reactions were monitored through sequential scans of the reaction medium with a probe in a one-liter batch reactor without collecting and preparing samples. To calibrate the NIR analytical method, gas chromatography-flame ionization detection was used as a reference method. The method was validated by studying the kinetics of the EtONa-catalyzed transesterification reaction. Activation energy (51.0 kJ/mol) was also determined by considering a pseudo second order kinetics model

Problematics of Applying Indigenous Oral History to Politico-Racial Reconciliation in Aotearoa/New Zealand

New Zealand is a country of four million people some 2000 kilometres east of Australia. It is internationally renowned for a number of things that reflect national mythology, such as landscape, flora and fauna, sporting prowess and - especially important for today's paper - race relations. The relations between Maori, the first arrivals a thousand years ago, and pakeha (non-Maori, mostly of British origin), has been lauded as being based on reciprocal tolerance, enlightened policies and mutual agreements - 'the best race relations in the world'. National myths, of course, seldom stand up fully to reality. Sizeable parts of the landscape have been stripped of forest, many indigenous species are under threat of extinction, the All Blacks did not reach the finals in the 2003 Rugby World Cup, and race relations, past and present, have been loaded with cultural misunderstandings and located within a conflictual rather than a consensual paradigm. This paper will outline how two separate historico-cultural worldviews, Maori and pakeha, have interrelated in a key recent political process - the addressing of indigenous claims relating to dispossession and marginalisation by colonisation. Such reconciliations are part of a global trend in former settler colonies whose governments perceive that discontented minorities are counterproductive to social progress. Reparational negotiations between the New Zealand Crown and tribes have, by international standards, been successful in their timelines and outcomes. Nevertheless they have presented many practical and conceptual difficulties, resulting in part from profound differences in worldview and, relatedly, historical methodology. On the other hand, the interaction between the two perspectives has enhanced the value and possibly durability of the reparations agreements. The paper analyses the role of oral history in these processes, and concludes that a consequence of the reconciliation project, an effort being made in various quarters to reconcile these two methodologies, presents cutting edge opportunities for scholarship

Skaitmeninių įrankių privalumai ir trūkumai siekiant rankraštiniuose laiškuose atkurti XIX amžiaus filosofijos skaitytojų emocijas

This article discusses the limitations and benefits of resorting to digital tools and research methodology to explore nineteenth-century manuscript letters, written by readers to the French philosopher Victor Cousin, and to increase our understanding of how ordinary readers responded to philosophy at the time. More broadly, it examines the potential assets of the annotation interface developed in the Reading Europe Advance Data Investigation Tool (READ-IT https://readit-project.eu/ 2018–2021), a collaborative research project focusing on regenerating lost connections about the cultural heritage of reading from large volumes of highly-diverse eighteenth- to twenty-first-century sources in multiple languages. The case study describes challenges raised by attempts to detect and classify differences between female and male philosophical reading experiences as well as emotional responses, something which is largely under-explored. Along the way it provides reflexive as well as epistemological insights into the promises of big data for research on cultural history and literary archives and the current state of knowledge on emotions.Šiame straipsnyje aptariami skaitmeninių įrankių ir tyrimo metodologijos trūkumai ir pranašumai tyrinėjant XIX amžiaus rankraštinius laiškus, kuriuos skaitytojai rašė prancūzų filosofui Victorui Cousinui, bei siekiant geriau suprasti paprastų skaitytojų reakciją į tuometę filosofiją. Kalbant plačiau, straipsnyje nagrinėjami potencialūs anotacijų sąsajos privalumai, atskleisti bendrame mokslinių tyrimų projekte „Reading Europe Advance Data Investigation Tool“ (READ-IT https://readit-project.eu/, 2018–2021 m.), kuriame pagrindinis dėmesys skiriamas atkurti prarastus ryšius apie skaitymo kultūros paveldą iš daugybės labai įvairių XVIII–XXI amžių šaltinių, skelbiamų keliomis kalbomis. Atvejo tyrime aprašomi iššūkiai, kylantys dėl bandymų aptikti ir tam tikrai kategorijai priskirti skirtumus tarp moterų ir vyrų filosofinio skaitymo patirties bei emocinių reakcijų, o tai iš esmės yra nepakankamai ištirta sritis. Be to, straipsnyje pateikiama refleksyvių ir epistemologinių įžvalgų apie didžiųjų duomenų teikiamas viltis kultūros istorijos ir literatūros archyvų tyrimams bei dabartinę žinių apie emocijas būklę

Spectral properties of a non-compact operator in ecology

Ecologists have recently used integral projection models (IPMs) to study fish and other animals which continue to grow throughout their lives. Such animals cannot shrink, since they have bony skeletons; a mathematical consequence of this is that the kernel of the integral projection operator T is unbounded, and the operator is not compact. To our knowledge, all theoretical work done on IPMs has assumed the operator is compact, and in particular has a bounded kernel. A priori, it is unclear whether these IPMs have an asymptotic growth rate λ, or a stable-stage distribution ψ. In the case of a compact operator, these quantities are its spectral radius and the associated eigenvector, respectively. Under biologically reasonable assumptions, we prove that the non-compact operators in these IPMs share some important traits with their compact counterparts: the operator T has a unique positive eigenvector ψ corresponding to its spectral radius λ, this λ is strictly greater than the supremum of the modulus of all other spectral values, and for any nonnegative initial population ϕ0, there is a c \u3e 0 such that T nϕ0/λn → c · ψ

A search for distant radio galaxies from SUMSS and NVSS: II. Optical Spectroscopy

This is the second in a series of papers presenting observations and results for a sample of 76 ultra-steep-spectrum (USS) radio sources in the southern hemisphere designed to find galaxies at high redshift. Here we focus on the optical spectroscopy program for 53 galaxies in the sample. We report 35 spectroscopic redshifts, based on observations with the Very Large Telescope (VLT), the New Technology Telescope (NTT) and the Australian National University's 2.3m telescope; they include five radio galaxies with z>3. Spectroscopic redshifts for the remaining 18 galaxies could not be confirmed: three are occulted by Galactic stars, eight show continuum emission but no discernible spectral lines, whilst the remaining seven galaxies are undetected in medium-deep VLT integrations. The latter are either at very high redshift (z >~7) or heavily obscured by dust. A discussion of the efficiency of the USS technique is presented. Based on the similar space density of z>3 radio galaxies in our sample compared with other USS-selected samples, we argue that USS selection at 843-1400 MHz is an efficient and reliable technique for finding distant radio galaxies.Comment: 15 Pages including 49 PostScript figures. Accepted for publication in MNRAS. Corrected one author name; text unchange

Towards understanding factors influencing the benefit of diversity in predator communities for prey suppression

It is generally assumed that high biodiversity is key to sustaining critical ecosystem services, including prey suppression by natural predator guilds. Prey suppression is driven by complex interactions between members of predator and prey communities, as well as their shared environment. Because of this, empirical studies have found both positive and negative effects of high predator diversity on prey suppression. However, we lack an understanding of when these different prey suppression outcomes will occur. In this work, we use a mechanistic, trait-based model to unravel how intraguild interactions, species body mass, predator foraging area, and ambient temperature can combine to produce different levels of prey suppression. Surprisingly, we find that prey suppression is only improved by high biodiversity under a limited set of conditions. The most important factor in determining whether diversity improves prey sup- pression is the amount of overlap between predators’ foraging areas. The degree of overlap in foraging areas shapes species interactions, and as the overlap between species increases, we see decreasing benefits from species-rich communities. In contrast, diversity in body mass only improves prey suppression when there is significant variation in temperature

La pratique des jeux de hasard et d’argent, les comportements délinquants et la consommation problématique de substances psychotropes : une perspective développementale

Cette étude comporte deux objectifs : 1) vérifier si les liens entre la pratique problématique des jeux de hasard et d’argent, les comportements délinquants et les problèmes de consommation de substances psychotropes diminuent au début de l’âge adulte par rapport au milieu de l’adolescence, et 2) vérifier si les liens entre ces trois ordres de comportements problématiques au début de l’âge adulte sont, en partie ou en totalité, attribuables à des antécédents communs. Deux échantillons populationnels de répondants de sexe masculin ont été mis à contribution afin de vérifier ces objectifs. Les mesures recueillies à 12 ans (i.e. les présumés antécédents communs) couvrent des aspects liés aux caractéristiques personnelles, familiales et sociales des participants. Celles recueillies à 16 et 23 ans se rapportent à leurs habitudes de jeu, à leurs comportements délinquants et à leur consommation de substances psychotropes. Ces dernières sont autorévélées alors que les précédentes font appel à des sources variées d’évaluation. Les résultats révèlent que les liens entre la pratique des jeux de hasard et d’argent, les comportements délinquants et la consommation de psychotropes au début de l’âge adulte (23 ans) sont similaires aux liens qui existent déjà à 16 ans. Ces liens ne peuvent toutefois pas être attribuables aux antécédents communs mesurés à la préadolescence (12 ans). La discussion explore les retombées pratiques et théoriques de ces résultats.This study addressed two questions: 1) Are the concurrent links between gambling, delinquency and drug use weaker during early adulthood than during middle adolescence; 2) Can the concurrent links by early adulthood be explained, at least in part, by common antecedent factors? Two population based samples of males were used to answer these questions. The putative common antecedent factors were assessed when the participants were 12 years old. These factors include variables from three domains of functioning: self, family and peers. Gambling, delinquency and drug use were assessed at age 16 years and again at age 23. Results show that the links between gambling, delinquency and drug use are not weaker by early adulthood (i.e. age 23) than they were by middle adolescence (i.e. age 16). In addition, these links cannot be explained by the age 12 antecedent factors. The discussion stresses the theoretical and applied implications of these findings

Do smokers have greater risk of delayed and non-union after fracture, osteotomy and arthrodesis?: a systematic review with meta-analysis

Objectives: Systematic review and meta-analysis of published observational cohort studies. To quantify the increased risk smokers have of experiencing a delayed and/or non-union in fractures, spinal fusion, osteotomy, arthrodesis or established non-unions. Setting: Medical Literature Analysis and Retrieval System Online (MEDLINE), Excerpta Medica database (EMBASE), Allied and Complementary Medicine Database (AMED) and Web of Science Core Collection from 1966 to 2015. Study eligibility criteria, participants and interventions: Observational cohort studies that reported adult smokers and non-smokers with delayed and/or non-union or time to union of the fracture, spinal fusion, osteotomy, arthrodesis or established non-union were eligible. Data extraction and outcome measures: 2 authors screen titles, abstracts and full papers. Data were extracted by 1 author and checked independently by a second. The relative risk ratios of smoking versus non-smoking and the mean difference in time to union patients developing a delayed and/or non-union were calculated. Results: The search identified 3013 articles; of which, 40 studies were included. The meta-analysis of 7516 procedures revealed that smoking is linked to an increased risk of delayed and/or non-union. When considered collectively, smokers have 2.2 (1.9 to 2.6) times the risk of experiencing delayed and/or non-union. In all the subgroups, the increased risk was always ≥1.6 times that of non-smokers. In the patients where union did occur, it was a longer process in the smokers. The data from 923 procedures were included and revealed an increase in time to union of 27.7 days (14.2 to 41.3). Conclusions: Smokers have twice the risk of experiencing a non-union after fracture, spinal fusion, osteotomy, arthrodesis or treatment of non-union. Time to union following fracture, osteotomy, arthrodesis or treatment of an established non-union is longer in smokers. Smokers should be encouraged to abstain from smoking to improve the outcome of these orthopaedic treatments

Development of continuous processes for vegetable oil alcoholysis in microfluidic devices

Biodiesel can be produced from vegetable oils, animal fats, and waste cooking oils by transesterification with ethanol (also called ethanolysis) in order to substitute fossil fuels. In this work, we were interested in the transesterification reaction of sunflower oil with ethanol, which leads to ethyl esters, used to date for applications principally in food and cosmetic industry. To open the application field to biofuels (to substitute current fuels resulting from fossil resources), the process efficiency has to be developed to be economically profitable. The batch reaction of vegetable oil ethanolysis was transposed to a micro-scaled continuous device (PFA tube of 508 mm internal diameter), inducing better heat and mass transfer. Study of the influence of the operational conditions (reactants flow, initial ethanol to oil molar ratio, temperature. . .) revealed the favourable reaction parameters necessary to reach high conversions and yields. In these conditions, it is possible to acquire kinetics data at the first seconds of the reaction, which was not feasible in a conventional batch process. These data were used to model occurring phenomena and to determine kinetic constants and transfer coefficients. The model was subsequently used to simulate reactions with other operational conditions. To acquire these data in microreactors, an on-line analysis method by Near InfraRed (NIR) spectroscopy was developed by using gas chromatography as a reference method. PLS models were then set up to quantify on-line the major compounds contents during the reaction