Miracle-dz/UniFAR-FTUs huggingface dataset:
Pyrolysis of tire rubber: Porosity and adsorption characteristics of the pyrolytic chars

Tire rubber has been pyrolyzed at various temperatures under a nitrogen atmosphere. The resulting chars have been analyzed for their porosity using nitrogen gas adsorption and for their aqueous adsorption characteristics using phenol, methylene blue, and the reactive dyes Procion Turquoise H-A and Procion Red H-E3B. Nitrogen adsorption isotherms were modeled to the BET and Dubinin−Astakhov (DA) equations to determine effective surface areas, mesopore volumes, and micropore volumes. Results showed that pyrolysis of tire rubber was essentially complete at 500 °C and resulted in a char yield of approximately 42 wt %. Pyrolytic chars exhibited BET surface areas up to 85 m2/g and micropore volumes up to 0.04 mL/g. Owing to their poorly developed micropore structure, the pyrolytic chars exhibited limited aqueous adsorption capacity for compounds of small molecular weight, such as phenol. However, the chars possessed significantly greater adsorption capacity for species of large molecular weight which was attrib.
Studies on the amount and composition of digesta flowing through the duodenum of dairy cows. 2. Sites of net absorption of magnesium and calcium from the alimentary tract.

1. The amounts of magnesium and calcium in the digesta flowing through the duodenum were measured direct in two cows fitted with re-entrant duodenal cannulas. A winter ration and a ration consisting of freshly mown herbage were given to both cows. Balance trials were carried out in the usual manner. Duodenal digesta were collected for 120 h in the middle of each balance period. In four other cows fitted with a T-piece cannula, the flow of duodenal digesta, Mg and Ca were estimated indirect by reference to poly(ethylene glycol) (PEG) and Cr 2 0 3 . Balance trials were carried out on these cows as above, and duodenal digesta were sampled every 2 h for 120 h in the middle of each balance period. 2. At normal Mg intakes there were no significant differences in net absorption of Mg proximal and distal to the duodenal cannula. At high Mg intakes net Mg absorption occurred mainly proximal to the duodenal cannula. Net Ca absorption was restricted to the intestines and a considerable net Ca secretion occurred proximal to the duodenal cannula. The amounts of chromium sesquioxide (Cr 2 0 3 ), Mg and Ca which passed through the duodenum during the first 24 h of digesta collection were measured and were compared with the amounts which passed during each 120-h collection period. Recoveries of Cr 2 0 3 averaged 85 and 98% at the end of 24 and 120 h respectively. The amounts of Mg and Ca which passed in the first 24 h were 99 and 96% of the mean amounts that passed during the 120-h collection. Experiments which combine the total collection of digesta for short periods (up to 24 h) with a correction factor to adjust first day's flow of digesta to give 100% recovery of the indicator may involve a considerable error. 3. Reliable conclusions on the sites of net Mg absorption could not be drawn, as the error attached to the indirect estimates in these four cows was too great, with respect to the small total net absorption of Mg. The results suggested, however, that Ca absorption was restricted to the intestines, with some secretion of Ca proximal to the duodenum. the results obtained by direct measurements in two cows fitted with re-entrant cannulas in the duodenum and by indirect estimates in four cows fitted with simple T-piece duodenal cannulas. This study of the experiment to assess the accuracy of indirect versus direct measurements of the flow of digesta and nutrients through the duodenum of cows Klooster al., 1972).
Thermal processing of miscanthus, sugarcane bagasse, sugarcane trash and their acid hydrolysis residues

The research presented in this thesis was developed as part of DIBANET, an EC funded project aiming to develop an energetically self-sustainable process for the production of diesel miscible biofuels (i.e. ethyl levulinate) via acid hydrolysis of selected biomass feedstocks. Three thermal conversion technologies, pyrolysis, gasification and combustion, were evaluated in the present work with the aim of recovering the energy stored in the acid hydrolysis solid residue (AHR). Mainly consisting of lignin and humins, the AHR can contain up to 80% of the energy in the original feedstock. Pyrolysis of AHR proved unsatisfactory, so attention focussed on gasification and combustion with the aim of producing heat and/or power to supply the energy demanded by the ethyl levulinate production process. A thermal processing rig consisting on a Laminar Entrained Flow Reactor (LEFR) equipped with solid and liquid collection and online gas analysis systems was designed and built to explore pyrolysis, gasification and air-blown combustion of AHR. Maximum liquid yield for pyrolysis of AHR was 30wt% with volatile conversion of 80%. Gas yield for AHR gasification was 78wt%, with 8wt% tar yields and conversion of volatiles close to 100%. 90wt% of the AHR was transformed into gas by combustion, with volatile conversions above 90%. 5volO2%-95vol%N2 gasification resulted in a nitrogen diluted, low heating value gas (2MJ/m3). Steam and oxygen-blown gasification of AHR were additionally investigated in a batch gasifier at KTH in Sweden. Steam promoted the formation of hydrogen (25vol%) and methane (14vol%) improving the gas heating value to 10MJ/m3, below the typical for steam gasification due to equipment limitations. Arrhenius kinetic parameters were calculated using data collected with the LEFR to provide reaction rate information for process design and optimisation. Activation energy (EA) and pre-exponential factor (ko in s-1) for pyrolysis (EA=80kJ/mol, lnko=14), gasification (EA=69kJ/mol, lnko=13) and combustion (EA=42kJ/mol, lnko=8) were calculated after linearly fitting the data using the random pore model. Kinetic parameters for pyrolysis and combustion were also determined by dynamic thermogravimetric analysis (TGA), including studies of the original biomass feedstocks for comparison. Results obtained by differential and integral isoconversional methods for activation energy determination were compared. Activation energy calculated by the Vyazovkin method was 103-204kJ/mol for pyrolysis of untreated feedstocks and 185-387kJ/mol for AHRs. Combustion activation energy was 138-163kJ/mol for biomass and 119-158 for AHRs. The non-linear least squares method was used to determine reaction model and pre-exponential factor. Pyrolysis and combustion of biomass were best modelled by a combination of third order reaction and 3 dimensional diffusion models, while AHR decomposed following the third order reaction for pyrolysis and the 3 dimensional diffusion for combustion.
Molecular Thermodynamics of Charged Hard-Dumbbell Fluids

Chemical potentials of charged hard-dumbbell fluids are obtained by Monte Carlo simulations using Widom's test-particle method, corresponding compressibility factors are achieved by integration of chemical potentials at different densities. A molecular thermodynamic model is also developed for these charged hard-dumbbell fluids where the residual Helmholtz function is composed of two terms: a reference term responsible for the charged hard spheres and a bonding contribution measuring the sticky interactions between positive and negative hard ions.Model predictions are in good agreement with simulation results.
Post-FEC BER Prediction for Bit-Interleaved Coded Modulation with Probabilistic Shaping

Accurate performance prediction after forward error correction (FEC) decoding is essential for system design in optical fiber communications. While generalized mutual information (GMI) has been shown to be successful for soft-decision decoded systems, for systems using probabilistic shaping (PS), GMI is less well correlated with the bit-error rate after softdecision decoding. The proposed metrics for such systems are instead normalized GMI (NGMI) and asymmetric information (ASI). They are good to predict BER after FEC decoding or to give an FEC limit in bit-interleaved coded modulation (BICM) with PS, but their relation has not been clearly explained so far. In this paper, we show that NGMI and ASI are equal under matched decoding but not under mismatched decoding. We also examine pre-FEC BER and ASI/NGMI over Gaussian and nonlinear fiber-optic channels with approximately matched decoding. ASI/NGMI always shows better correlation with post-FEC BER than pre-FEC BER for BICM with PS. On the other hand, post-FEC BER can differ at a given ASI/NGMI when we change the bit mapping, which describes how each bit in a codeword is assigned to a bit tributary.
Immobilizing Chitosan-Stabilized Palladium Nanoclusters on Titanium Dioxide and Their Catalytic Hydrogenation Properties

Four methods of immobilization of palladium nanoparticles stabilized by chitosan on the surface of titanium have been conducted. The immobilization techniques were denoted with catalysts symbols of [Pd 0 -chi-TiO 2 ], [Pd 0 -chi]-TiO 2 , [Pd0-chi]-TiO 2 - cross and Pd 0 -[chi-TiO 2 ]. Pd 0 [chi-TiO 2 ] that was prepared by wet impregnation of palladium ions on the surface of titanium-coated chitosan and palladium ions were reduced by refluxing in methanol, produced palladium nano particles catalyst with high catalytic activities compared with those prepared with other methods. The catalytic activity for conversion of nitrobenzene to aniline at 30 o C and 1 atm followed the trend of Pd 0 -[chi-TiO 2 ] > [Pd 0 -chi-TiO 2 ] > [Pd0-chi]-TiO 2 > [Pd 0 -chi]-TiO 2 - cross. Most of the palladium metal particles in Pd 0 -[chi-TiO 2 ] were exposed and dispersed with average size of 7.3 nm, while without chitosan, the particles were larger, aggregated and had of low catalytic activity.
Controlling ZIF-8 nano and microcrystal formation and reactivity through zinc salts variations

Metal organic frameworks (MOFs) are porous crystalline materials composed of metal ions or clusters of metal ions coordinated with organic linkers (such as terephthalic acid, 1,3,5-benzenetricarboxylic acid, or imidazoles). MOFs exhibit tunable structures, low density, ultrahigh surface area and have various potential applications in catalysis, hydrogen storage, and adsorption/separation of liquid or gaseous mixtures. Among the MOFs structures, the zeolitic imidazolate frameworks (ZIFs) have recently attracted considerable attention. In these materials, metal atoms such as Zn2+ are linked through N atoms by the ditopic 2-methylimidazolate ligand to form neutral frameworks. ZIF-8 has a sodalite zeolite-type topology with cages of 11.6 A and pores of 3.4 A in diameter. ZIF-8 are characterized by high thermal stability (550 oC in N2), large surface area (BET: 1630 m2/g) and high resistance to various solvents. Concerning ZIF-8 chemical properties, these materials can successfully be used for hydrogen, carbon dioxide and iodide storage, Knoevenagel condensations, cycloadditions, oxidations, trans-esterification, and Friedel-Crafts alkylations. Variations of synthetic parameters (solvent, concentration, temperature, time, molar ratio of reactants) are commonly used to manipulate the morphology and size of ZIF-8 crystals. In this work, we demonstrate that the reactivity of the Zn(+2) salt in the growth solution can also markedly affect the size and the morphology of ZIF-8 particles. Small ZIF-8 nanocrystals with diameters varying between ca. 50 and 200 nm were obtained with reactive zinc salts like Zn(acac)2, Zn(NO3)2, ZnSO4 or Zn(ClO4)2. The use of ZnCl2, Zn(OAc)2 or ZnI2 afforded crystals with sizes varying between ca. 350 and 650 nm. Finally, the low reactive ZnBr2 was found to generate microsized crystals. These significant changes in particle size induced distinctive changes in adsorption properties as demonstrated by BET measurements but also in the catalytic performances of ZIF-8 crystals in a Knoevenagel condensation used as model. The small sized crystals produced from Zn(NO3)2 exhibit the highest surface area and the best catalytic activity.
Supercritical Water as a Reaction Medium for Nitrogen-Containing Heterocycles

Supercritical water has been focused on as an environmentally attractive reaction media, in which organic materials can be decomposed into smaller molecules. The reaction behavior of pyrrole as a simple model compound of nonbasic nitrogen compounds found in petroleum residua was studied in supercritical water with a batch type reactor. The reaction was carried out at temperatures of 698-748 K and at various pressures under an argon atmosphere. The chemical species in the aqueous products were identified by GCMS (gas chromatography mass spectrometry) and quantified using GC-FID (gas chromatography flame ionization detector). The effect of temperature and reaction time on the conversion process of pyrrole is presented. Under supercritical water conditions, pyrrole underwent successful decomposition in water into its derived compounds. The conversion of pyrrole could approach 81.12 wt% at 723 K and 40 MPa within 240 min of reaction time. The decomposition process was accelerated with the existence of water at the same temperature. Ultimate analysis of solid products was also conducted using a CHN analyzer. The process investigated in this study may form the basis for an efficient method of nitrogen compound decomposition in future.
A molecular and isotopic study of the macromolecular organic matter of the ungrouped C2 WIS 91600 and its relationship to Tagish Lake and PCA 91008

Abstract– Insight into the chemical history of an ungrouped type 2 carbonaceous chondrite meteorite, Wisconsin Range (WIS) 91600, is gained through molecular analyses of insoluble organic matter (IOM) using solid‐state 13C nuclear magnetic resonance (NMR) spectroscopy, X‐ray absorption near edge structure spectroscopy (XANES), and pyrolysis‐gas chromatography coupled with mass spectrometry (pyr‐GC/MS), and our previous bulk elemental and isotopic data. The IOM from WIS 91600 exhibits similarities in its abundance and bulk δ15N value with IOM from another ungrouped carbonaceous chondrite Tagish Lake, while it exhibits H/C, δ13C, and δD values that are more similar to IOM from the heated CM, Pecora Escarpment (PCA) 91008. The 13C NMR spectra of IOM of WIS 91600 and Tagish Lake are similar, except for a greater abundance of CHxO species in the latter and sharper carbonyl absorption in the former. Unusual cross‐polarization (CP) dynamics is observed for WIS 91600 that indicate the presence of two physically distinct organic domains, in which the degrees of aromatic condensation are distinctly different. The presence of two different organic domains in WIS 91600 is consistent with its brecciated nature. The formation of more condensed aromatics is the likely result of short duration thermal excursions during impacts. The fact that both WIS 91600 and PCA 91008 were subjected to short duration heating that is distinct from the thermal history of type 3 chondrites is confirmed by Carbon‐XANES. Finally, after being briefly heated (400 °C for 10 s), the pyrolysis behavior of Tagish Lake IOM is similar to that of WIS 91600 and PCA 91008. We conclude that WIS 91600 experienced very moderate, short duration heating at low temperatures (<500 °C) after an episode of aqueous alteration under conditions that were similar to those experienced by Tagish Lake.
Using electrostatic interactions to control supramolecular self-assembly on metallic surfaces

Supramolecular self-assembly on metallic surfaces is the ideal playground for studying a variety of physical and chemical phenomena. Adsorbed molecules will diffuse and self-organise to form assemblies dictated by their functionalities, while the more or less pronounced metal reactivity will accordingly affect both the supramolecular patterns and the interfacial chemistry. Besides structural aspects, electronic properties are central in determining the energy level alignment at the heterojunction and, thus, the performance of organic-based devices. Notably, charge reorganisation at the metal-organic interface will produce surface dipoles, whose effect is to add electrostatic repulsion to the dispersion-driven supramolecular self-assembly and to change the work function of the surface. Herein, the relation between charge migration (i.e., the creation of surface dipoles) and molecular self-assembly is addressed by studying the behaviour of on-purpose designed molecular units on selected metals. We will show that choosing the substrate on the basis of its work function can selectively allow or inhibit the transfer of charge from the organic material to the electrode. When charge transfer occurs, the growing supramolecular structures exhibit a phase modulation driven by the presence of competing interactions. Moreover, the introduction of reactive moieties in formerly inert tectons will be identified as a suitable strategy for promoting the formation of interfacial dipoles upon surface-mediated chemical reactions. Our work paves the way for a more rational approach to the design of metal-organic systems, as we speculate that charge transfer effects and surface chemistry can be predicted at the stage of molecular design, at variance with the current trial and error approach used in the field of organic electronics. This thesis is based on multiscale theoretical modelling of selected metalmolecule couples and it is the result of a fruitful collaboration with the groups of Prof Davide Bonifazi (Université de Namur) and Prof Giovanni Costantini (University of Warwick).
Modeling of homogeneous charge compression ignition (HCCI) of methane

The operation of piston engines on a compression ignition cycle using a lean, homogeneous charge has many potential attractive features. These include the potential for extremely low NO{sub x} and particulate emissions while maintaining high thermal efficiency and not requiring the expensive high pressure injection system of the typical modem diesel engine. Using the HCT chemical kinetics code to simulate autoignition of methane-air mixtures, we have explored the ignition timing, burn duration, NO{sub x} production, indicated efficiency and power output of an engine with a compression ratio of 15:1 at 1200 and 2400 rpm. HCT was modified to include the effects of heat transfer. This study used a single control volume reaction zone that varies as a function of crank angle. The ignition process is controlled by varying the intake equivalence ratio and varying the residual gas trapping (RGT). RGT is internal exhaust gas recirculation which recycles both heat and combustion product species. It is accomplished by varying the timing of the exhaust valve closure. Inlet manifold temperature was held constant at 330 Kelvins. Results show that there is a narrow range of operational conditions that show promise of achieving the control necessary to vary power output while keeping indicated more » efficiency above 50% and NO{sub x} levels below 100 ppm. « less
Influence des hydroxypropylguars sur les propriétés des mortiers de ciment à l’état frais

L’ajout d’adjuvants dans les mortiers permet d’obtenir diverses proprietes selon lesperformances souhaitees. Les polysaccharides sont utilises pour ameliorer la capacite deretention d’eau et le comportement rheologique du mortier. Cependant, ils engendrent unretard de prise du ciment et representent un poids economique considerable. Il apparait doncque la comprehension de l’interaction entre les polysaccharides et le ciment est necessaire.Etant donne que les comportements sont differents selon le type de polysaccharide, l’etuded’une nouvelle famille de polysaccharides constitue un axe de recherche majeur. Leshydroxypropylguars (HPG) ont ete choisis car ils ont ete presentes comme de tres bonsagents retenteurs d’eau et sont deja utilises industriellement.Il s’avere que les HPG conferent effectivement aux mortiers d’excellentes proprietes deretention d’eau. Le mecanisme de retention d’eau est attribue a la formation d’agglomeratsqui, au-dela d’une concentration critique, bouchent le reseau poreux a l’interface mortier-substrat.De plus, ces molecules ralentissent nettement la cinetique d’hydratation du cimenten modifiant la croissance des hydrates par adsorption. Les HPG augmentent egalement la contrainte seuil de cisaillement et la consistance des mortiers. Toutes cesproprietes different lorsque les HPG sont introduits pre-dissout dans l’eau de gâchee. Unemethodologie de fragmentation par ultra-sons des polysaccharides a ete developpee dans lebut d’etudier l’impact de leur masse moleculaire sur les proprietes des mortiers a l’etat frais.Sur tous ces aspects, le comportement des HPG a ete compare a celui des ethers de cellulose,adjuvants retenteur d’eau de reference.
Investigation of Dissipation, Adsorption, Degradation, and Leaching of Triazophos Pesticide in Various Soils

This study concerns the investigation of dissipation, adsorption, and degradation of triazophos in different soils from Pakistan. These processes help in the disappearance of pesticide from the environment. Gas chromatography was used for dissipation and adsorption analysis while for degradation study mass spectrometer was used in addition of gas chromatography (GC-MS). The dissipation rate of triazophos in three different soils was 90% over 30 days with average half-life of 9.059 days. From dissipation study it was inferred that rate is variable in each soil due to climatic changes, soil nature and soil-pesticide interactions. Adsorption experiment has revealed that the adsorption of this pesticide to soil follows the pseudo first order kinetic model with rate constant value of 0.479/h and Freundlich isotherm with adsorption capacity of 1.832 mol/g. Degradation study has displayed two major metabolites, one is phosphorothioic acid, S-[2-[(1-cyano-1-methylethyl) amino]-2-oxoethyl] O,O-diethyl ester at retention time of 9.136 and the other is sulfotep at 14.304 min. The leaching potential of triazophos was also calculated from its half-life and organic carbon content present in soil which was 1.688 representing it as non leacher pesticide.
Composition dependence of Si and Ge diffusion in relaxed Si1−xGex alloys

Diffusion of silicon (Si) and germanium (Ge) in silicon-germanium Si1−xGex-isotope heterostructures with Ge contents x=0, 0.05, 0.25, 0.45, and 0.70 was investigated in a temperature range between 690 and 1270 °C. The concentration profiles of the stable Si-isotopes and Ge-isotopes were recorded by means of time-of-flight secondary ion mass spectrometry. Analysis of the experimental profiles shows that the Si and Ge diffusion coefficients in elemental Si agree within experimental accuracy. However with increasing Ge content the diffusion of Ge gets increasingly faster compared to that of Si. An Arrhenius type temperature dependence of diffusion is observed for all compositions with slightly lower values for the activation enthalpy of Ge compared to Si. The more pronounced Ge diffusion indicates that with increasing Ge concentration the diffusional jumps of Ge atoms become more successful compared to those of Si. This trend is explained with an increasing contribution of vacancies to self-diffusion in Si1−.
EFEITO DO AIB E DE DIFERENTES TIPOS DE ESTACA NA PROPAGAÇÃO VEGETATIVA DA GOIABEIRA-SERRANA (Acca sellowiana Berg)

O trabalho foi realizado na Embrapa Clima Temperado, Pelotas, RS, com o objetivo de verificar o efeito do AIB no enraizamento de diferentes estacas de goiabeira-serrana. Foram conduzidos dois experimentos, um com estacas lenhosas, avaliando o efeito do AIB (0, 200 e 400 mg L -1 ), em imersao das estacas por 24 horas, retiradas de diferentes porcoes do ramo ( apical, mediana e basal). O segundo com estacas herbaceas, avaliando o efeito do AIB (0, 2000, 4000 e 8000 mg L -1 ) sobre estacas de diferentes tamanhos (12 e 18 cm). Nao ocorreu formacao de raizes em estacas de goiabeira-serrana em nenhum dos tratamentos aplicados. A sobrevivencia de estacas lenhosas tendeu a ser maior naquelas retiradas da porcao basal dos ramos, e em estacas herbaceas com 12 cm de comprimento a ser maior do que naquelas com 18 cm. Houve fitotoxidez por AIB em estacas herbaceas, em concentracoes a partir de 4000 mg L -1 , e baixo percentual de formacao de calo em estacas herbaceas .