Bifunctional SO4/ZrO2 catalysts for 5-hydroxymethylfufural (5-HMF) production from glucose

The telescopic conversion of glucose to fructose and then 5-hydroxymethylfurfural (5-HMF), the latter a potential, bio-derived platform chemical feedstock, has been explored over a family of bifunctional sulfated zirconia catalysts possessing tuneable acid-base properties. Characterisation by acid-base titration, XPS, XRD and Raman reveal that submonolayer SO4 coverages offer the ideal balance of basic and Lewis-Brønsted acid sites required to respectively isomerise glucose to fructose, and subsequently dehydrate fructose to 5-HMF. A constant acid site normalised turnover frequency is observed for fructose dehydration to 5-HMF, confirming a common Brønsted acid site is responsible for this transformation. This journal is © The Royal Society of Chemistry.

Tuning solid acid catalysts for glucose conversion to platform chemicals

Worldwide concern over dwindling fossil fuel reserves and impact of CO2 emissions on climate change means there is an urgent need to reduce our dependence on oil based sources of fuels and chemicals. The direct conversion of lignocellulosic derived glucose to 5-Hydroxymethylfurfural (5-HMF) is an attractive process for the production of chemicals and fuels but requires a bi-functional catalyst with acid-base or Lewis-Brönsted sites which can operate efficiently in the aqueous phase. While conventionally viewed as a superacid, the potential for tuning the acid strength in SO4/ZrO2 and potential for coupling bi-functional ZrO2-SO4/ZrO2 sites at low sulfate contents have been overlooked. Our previous work has shown effective tuning of the acid strength in SO4/ZrO2 can be used to direct selectivity in terpene isomerisation thus we rationalised control over HMF selectivity could achieved in a similar fashion. Here we report on a systematic study of the impact of acid properties of SO4/ZrO2 catalysts on the conversion of C6 sugars to 5-HMF in aqueous media and correlate the surface acid-base properties with glucose isomerisation and dehydration capabilities.

Conformal sulfated zirconia monolayer catalysts for the one-pot synthesis of ethyl levulinate from glucose

Here we describe a simple route to creating conformal sulphated zirconia monolayers throughout an SBA-15 architecture that confers efficient acid-catalysed one-pot conversion of glucose to ethyl levulinate.

Enhancing Information Retrieval by Using Evolution Strategies

Similar to Genetic algorithm, Evolution strategy is a process of continuous reproduction, trial and selection. Each new generation is an improvement on the one that went before. This paper presents two different proposals based on the vector space model (VSM) as a traditional model in information Retrieval (TIR). The first uses evolution strategy (ES). The second uses the document centroid (DC) in query expansion technique. Then the results are compared; it was noticed that ES technique is more efficient than the other methods.

Using a Query Expansion Technique to Improve Document Retrieval

Query expansion (QE) is a potentially useful technique to help searchers formulate improved query statements, and ultimately retrieve better search results. The objective of our query expansion technique is to find a suitable additional term. Two query expansion methods are applied in sequence to reformulate the query. Experiments on test collections show that the retrieval effectiveness is considerably higher when the query expansion technique is applied.

Valorisation of vietnamese rice straw waste:catalytic aqueous phase reforming of hydrolysate from steam explosion to platform chemicals

A family of tungstated zirconia solid acid catalysts were synthesised via wet impregnation and subsequent thermochemical processing for the transformation of glucose to 5-hydroxymethylfurfural (HMF). Acid strength increased with tungsten loading and calcination temperature, associated with stabilisation of tetragonal zirconia. High tungsten dispersions of between 2 and 7 W atoms·nm−2 were obtained in all cases, equating to sub-monolayer coverages. Glucose isomerisation and subsequent dehydration via fructose to HMF increased with W loading and calcination temperature up to 600 °C, indicating that glucose conversion to fructose was favoured over weak Lewis acid and/or base sites associated with the zirconia support, while fructose dehydration and HMF formation was favoured over Brönsted acidic WOx clusters. Aqueous phase reforming of steam exploded rice straw hydrolysate and condensate was explored heterogeneously for the first time over a 10 wt% WZ catalyst, resulting in excellent HMF yields as high as 15% under mild reaction conditions.

Hydrothermally stable, conformal, sulfated zirconia monolayer catalysts for glucose conversion to 5-HMF

The grafting and sulfation of zirconia conformal monolayers on SBA-15 to create mesoporous catalysts of tunable solid acid/base character is reported. Conformal zirconia and sulfated zirconia (SZ) materials exhibit both Brönsted and Lewis acidity, with the Brönsted/Lewis acid ratio increasing with film thickness and sulfate content. Grafted zirconia films also exhibit amphoteric character, whose Brönsted/Lewis acid site ratio increases with sulfate loading at the expense of base sites. Bilayer ZrO2/SBA-15 affords an ordered mesoporous material with a high acid site loading upon sulfation and excellent hydrothermal stability. Catalytic performance of SZ/SBA-15 was explored in the aqueous phase conversion of glucose to 5-HMF, delivering a 3-fold enhancement in 5-HMF productivity over nonporous SZ counterparts. The coexistence of accessible solid basic/Lewis acid and Brönsted acid sites in grafted SZ/SBA-15 promotes the respective isomerization of glucose to fructose and dehydration of reactively formed fructose to the desired 5-HMF platform chemical.

A new inverse DEA method for merging banks

This study suggests a novel application of Inverse Data Envelopment Analysis (InvDEA) in strategic decision making about mergers and acquisitions in banking. The conventional DEA assesses the efficiency of banks based on the information gathered about the quantities of inputs used to realize the observed level of outputs produced. The decision maker of a banking unit willing to merge/acquire another banking unit needs to decide about the inputs and/or outputs level if an efficiency target for the new banking unit is set. In this paper, a new InvDEA-based approach is developed to suggest the required level of the inputs and outputs for the merged bank to reach a predetermined efficiency target. This study illustrates the novelty of the proposed approach through the case of a bank considering merging with or acquiring one of its competitors to synergize and realize higher level of efficiency. A real data set of 42 banking units in Gulf Corporation Council countries is used to show the practicality of the proposed approach.

Földfelvásárlások Afrikában

Egy brit hátterű multinacionális cég, a ProCana igen komoly beruházást jelentett be 2007-ben: Mozambik Massingir nevű régiójában egy nagykapacitású bioetanol üzemet kívántak felépíteni. Ennek érdekében összesen 30 000 hektár földet kívántak bérelni a mozambiki kormánytól, amin cukornádat termeltek volna. A terv szerint a termésből helyben készült bioetanolt a maputói kikötőben tankhajókba töltve Európába exportáltak volna. A beruházás értékét több mint félmilliárd dollárra tették, amely nagyjából 2 000 munkahelyet teremtett volna, nem is beszélve arról, hogy jelentősen hozzájárult volna Mozambik infrastruktúrájának fejlődéséhez és az exportjának növekedéséhez.

Parametrikus nyugdíjreformok és életciklus-munkakínálat (Parametric pension reforms and life-cycle labour supply)

A társadalombiztosítási nyugdíjrendszer finanszírozása pusztán a demográfiai folyamatok következtében is jelentős terhet ró majd a költségvetésére, amin a különböző parametrikus és paradigmatikus nyugdíjreformok enyhíthetnek. A reformok azonban hosszú távon olyan viselkedési, munkakínálati reakciókat válthatnak ki, amelyek alapvetően változtatják meg a költségvetési hatásokat. Az 1999 és 2009 között Magyarországon megfigyelhető átlagos munka- és nyugdíjkorprofilok bemutatása után arra tettünk kísérletet, hogy mikroökonómiai alapon határozzuk meg néhány alapvető parametrikus nyugdíjreformnak a férfiak életciklus-munkakínálatára gyakorolt hatását. A modell paramétereit a magyar gazdaság 1999 és 2009 közötti jellemzőinek megfelelően kalibráltuk. Eredményeink szerint a helyettesítési ráta csökkentése, a nyugdíjkorhatár emelése és a svájci indexálás árindexálásra cserélése összességében számottevően növeli az egyes képzettségi csoportok munkakínálatát, s a fiatalabb korosztályok javára csoportosítja át az életciklus-munkakínálatot, míg a nyugdíj kiszámításához figyelembe vett évek számának megváltoztatása nem hoz jelentős aggregált hatást, és nem jár a munkakínálat korcsoportok közötti átcsoportosításával. ____ Financing the social-security pension system will weigh heavily on the government budget in developed countries, merely through the projected demographic processes. The burden could be eased by various parametric and paradigmatic pension reforms, but in the long run such reforms may trigger behavioural, labour-supply responses, which may alter the budgetary effects fundamentally. Having described the average work and pension profiles in Hungary between 1999 and 2009, the authors use a microeconomic approach in an attempt to assess the effect of certain parametric pension reforms on the life-cycle labour supply of males. The parameters for the model were calibrated for the characteristics of the Hungarian economy. The results show that decreasing the replacement rate, increasing the retirement age and replacing Swiss indexation of pensions by price indexation cause a considerable increase in the labour supply of all education-level groups, whereas changing the number of years considered in computing pensions does not have a significant aggregate effect. While introducing price indexation increases the labour supply of all cohorts by the same amount, the other reforms reallocate the life-cycle labour supply, mainly towards younger age-groups.

A magyar différance

A tanulmányban a szerző arra tesz kísérletet, hogy Magyarországnak az euró bevezetésével kapcsolatos halogató magatartását egy rendszerszemléletű megközelítésen keresztül értelmezze. A makrogazdasági (in)stabilitás kérdését interdiszciplináris megközelítéssel tárgyalja, amelynek során olyan területek releváns ismereteire támaszkodik, mint a fejlődéstan, az új politikai gazdaságtan, a pszichológia és a komplexitás tudománya. Fő következtetése az, hogy az euró bevezethetőségének egyik peremfeltétele a politikai-társadalmi-gazdasági rendszerbe, mint innovációs ökoszisztémába injektált pótlólagos bizonytalanság mérséklése, amin keresztül a vázolt magyar attitűd is megtörhető.

Efficiency and power density improvement of grid-connected hybrid renewable energy systems utilizing high frequency-based power converters

High efficiency of power converters placed between renewable energy sources and the utility grid is required to maximize the utilization of these sources. Power quality is another aspect that requires large passive elements (inductors, capacitors) to be placed between these sources and the grid. The main objective is to develop higher-level high frequency-based power converter system (HFPCS) that optimizes the use of hybrid renewable power injected into the power grid. The HFPCS provides high efficiency, reduced size of passive components, higher levels of power density realization, lower harmonic distortion, higher reliability, and lower cost. The dynamic modeling for each part in this system is developed, simulated and tested. The steady-state performance of the grid-connected hybrid power system with battery storage is analyzed. Various types of simulations were performed and a number of algorithms were developed and tested to verify the effectiveness of the power conversion topologies. A modified hysteresis-control strategy for the rectifier and the battery charging/discharging system was developed and implemented. A voltage oriented control (VOC) scheme was developed to control the energy injected into the grid. The developed HFPCS was compared experimentally with other currently available power converters. The developed HFPCS was employed inside a microgrid system infrastructure, connecting it to the power grid to verify its power transfer capabilities and grid connectivity. Grid connectivity tests verified these power transfer capabilities of the developed converter in addition to its ability of serving the load in a shared manner. In order to investigate the performance of the developed system, an experimental setup for the HF-based hybrid generation system was constructed. We designed a board containing a digital signal processor chip on which the developed control system was embedded. The board was fabricated and experimentally tested. The system's high precision requirements were verified. Each component of the system was built and tested separately, and then the whole system was connected and tested. The simulation and experimental results confirm the effectiveness of the developed converter system for grid-connected hybrid renewable energy systems as well as for hybrid electric vehicles and other industrial applications.

Noradrenergic modulatoins of odor learning and odor representation in the rat

How experience alters neuronal ensemble dynamics and how locus coeruleus-mediated norepinephrine release facilitates memory formation in the brain are the topics of this thesis. Here we employed a visualization technique, cellular compartment analysis of temporal activity by fluorescence in situ hybridization (catFISH), to assess activation patterns of neuronal ensembles in the olfactory bulb (OB) and anterior piriform cortex (aPC) to repeated odor inputs. Two associative learning models were used, early odor preference learning in rat pups and adult rat go-no-go odor discrimination learning. With catFISH of an immediate early gene, Arc, we showed that odor representation in the OB and aPC was sparse (~5-10%) and widely distributed. Odor associative learning enhanced the stability of the rewarded odor representation in the OB and aPC. The stable component, indexed by the overlap between the two ensembles activated by the rewarded odor at two time points, increased from ~25% to ~50% (p = 0.004-1.43E⁻4; Chapter 3 and 4). Adult odor discrimination learning promoted pattern separation between rewarded and unrewarded odor representations in the aPC. The overlap between rewarded and unrewarded odor representations reduced from ~25% to ~14% (p = 2.28E⁻⁵). However, learning an odor mixture as a rewarded odor increased the overlap of the component odor representations in the aPC from ~23% to ~44% (p = 0.010; Chapter 4). Blocking both α- and β-adrenoreceptors in the aPC prevented highly similar odor discrimination learning in adult rats, and reduced OB mitral and granule ensemble stability to the rewarded odor. Similar treatment in the OB only slowed odor discrimination learning. However, OB adrenoceptor blockade disrupted pattern separation and ensemble stability in the aPC when the rats demonstrated deficiency in discrimination (Chapter 5). In another project, the role of α₂-adrenoreceptors in the OB during early odor preference learning was studied. OB α2-adrenoceptor activation was necessary for odor learning in rat pups. α₂-adrenoceptor activation was additive with β-adrenoceptor mediated signalling to promote learning (Chapter 2). Together, these experiments suggest that odor representations are highly adaptive at the early stages of odor processing. The OB and aPC work in concert to support odor learning and top-down adrenergic input exerts a powerful modulation on both learning and odor representation.

The effect of ultrasonic waves on the phase behavior of a surfactant-brine-oil system

Acknowledgements The authors would like to gratefully acknowledge and appreciate the School of Engineering, University of Aberdeen, Aberdeen, Scotland, UK, for the provision of the laboratory facilities necessary for completing this work.