Miracle-dz/UniFAR-FTUs huggingface dataset:
Characterization of fine particulate sources at Ashaiman in Greater Accra, Ghana

Abstract The sources of airborne fine particles in PM 2.5 range influencing air quality at Ashaiman, a semi–urban town north of Tema in Ghana had been investigated. Nuclepore and quartz fiber filters were used for the air particulate loadings and analyzed for elemental and carbonaceous compound (EC and OC) concentrations in the 8 carbon fractions using X–Ray spectrometry system and IMPROVE/Thermal Optical Reflectance method respectively. Positive matrix factorization (PMF) was utilized to identify the following eight sources; industrial emissions (11.4%), fresh sea salt (15.5%), diesel emissions (18.4%), biomass burning (9.5%), two stroke engines (5.1%), gasoline emissions (15.8%), aged sea salt (6.2%), and soil dust (17.7%). Source locations were verified by means of Conditional Probability Function (CPF) plots that utilize wind directions. The source contributions revealed the high influence of fossil fuel and biomass combustion on the air quality in Ashaiman. The presence of the harbor and the industries located at Tema were seen to have substantial impacts on respirable air particulate matter (APM) concentrations in Ashaiman.
Seasonal variations in trace metal levels, speciation and physicochemical determinants of metal availability in dumpsite soils within Akwa Ibom State, Nigeria

Physicochemical properties, total metals and metal species were investigated in surface soil samples from six urban dumpsites within Akwa Ibom State, Nigeria. Results obtained indicated that Pb, Cd and Cr levels were higher in the dry season than in wet season, whereas Ni levels were higher during the wet season. Soil pH, organic matter and cation-exchange capacity (CEC) showed higher values in wet season than in dry season, whereas sand and clay levels were higher in the dry season. Speciation analysis showed the principal fraction of the metals to be Pb (reducible), Cd (acid extractable) and Ni (residual), whereas Cr existed in the residual fraction during the dry season and in the acid-extractable fraction during the wet season. Soil pH was positively correlated at p<0.1 with all metals in both seasons, sand was negatively correlated with the metals in both seasons, and CEC was negatively correlated with all metals in both seasons, except Pb in the wet season. Organic matter showed variable relationships with metals in both seasons. Seasonal variations affected metal availability and physicochemical properties of the soil. Total metal concentrations followed the order Pb>Ni>Cd>Cr, whereas their bioavailability followed the trend Cd>Pb>Cr>Ni.
Enhanced thermal conductivity of PEG/diatomite shape-stabilized phase change materials with Ag nanoparticles for thermal energy storage

Ag nanoparticles (AgNPs) are a promising additive because they can enhance the thermal conductivity of organic phase change materials. In this paper, a series of high thermally-conductive shape-stabilized phase change materials (ss-PCMs) were tailored by blending PEG with AgNP-decorated diatomite. In order to enlarge its pore size and specific surface area and make it a suitable PEG carrier, the effect of alkali leaching on the microstructure of diatomite was studied. While PEG melted during phase transformation, the maximum load of PEG could reach 63 wt%, which was 31% higher than that of the raw diatomite. Spherical-shaped crystalline AgNPs with a diameter range of 3–10 nm were uniformly decorated onto diatomite. The XPS results for this material proved that the valence state of silver in the PEG/diatomite PCM was mainly zero. The phase change enthalpy of the PEG/diatomite/Ag PCM reached 111.3 J g−1, and the thermal conductivity of the PEG/diatomite PCM containing 7.2 wt% Ag was 0.82 W m−1 K−1, which was 127% higher than that of the PEG/diatomite composite. The reduced melting and freezing periods indirectly proved that heat transfer in the composite material during the heat storage and release process was enhanced through the thermal conductivity improvement. The composite PCM was thermally and chemically stable even after 200 cycles of melting and freezing. This indicated that the resulting composite PCMs were promising candidate materials for building applications due to their large latent heat, suitable phase change temperature, excellent chemical compatibility, improved supercooling extent, and high thermal stability.
Phenol removal from industrial wastewaters: a short review

AbstractThe toxicity of phenol even at low concentrations in industrial effluents is high enough to meet its needs for separation. In this paper, a review will be carried out on the traditional techniques and recent advances in the separation of phenol from its contaminated streams. The most commonly used methods classified based on the phenol concentrations (high, medium, and low), and also, their advantages and disadvantages that should be considered in the design of industrial wastewater treatment systems will be discussed. Finally, the best methods will be suggested for each concentration range at the influent and, of course, that is allowable in the final effluent. The survey results recommended that biodegradation, chemical, electrochemical, and photocatalytic oxidation, solid phase extraction, ozonation, reverse osmosis/nanofiltration, and wet air oxidation are useful methods in low phenol concentrations, whereas liquid–liquid extraction, pervaporation, membrane-based solvent extraction, adsorption.
ELABORAÇÃO DE BEBIDA FERMENTADA UTILIZANDO CALDA RESIDUAL DA DESIDRATAÇÃO OSMÓTICA DE ABACAXI (Ananas comosus L.)

A industrializacao de frutas emprega tecnologias que visam diminuir as perdas durante o transporte e armazenamento das frutas, alem de agregar valor ao produto e aumentar sua vida de prateleira. Dentre as tecnologias mais utilizadas esta a desidratacao osmotica e producao de fruta cristalizada. Como subproduto destes processos sobra uma calda que ainda contem um elevado conteudo de acucares, alem de reter o aroma e sabor da fruta. Assim, esse trabalho teve como objetivo aproveitar a calda residual da desidratacao osmotica do abacaxi para elaboracao de uma bebida fermentada. Para isso, a calda foi diluida ate cerca de 25 oBrix e tratada com metabissulfito de potassio para evitar a contaminacao por leveduras invasoras e outros microrganismos. Ao mosto foi inoculada a levedura Saccharomyces cerevisiae e a fermentacao foi conduzida em fermentadores plasticos, com tres repeticoes, durante 90 dias. Para avaliar a qualidade do produto, foram realizadas analises fisico-quimicas e sensoriais. A analise sensorial (teste de aceitacao) foi realizada atraves de escala hedonica estruturada, com um grupo de 30 provadores nao-treinados constituido de alunos e funcionarios da Universidade Federal do Reconcavo da Bahia, de ambos os sexos. Os experimentos resultaram em um fermentado de cor clara, levemente amarelado, com teor alcoolico de 12,3 oGL. O fermentado foi bem aceito de acordo com a analise sensorial.
Composition and Antimicrobial Activity of Salvia amplexicaulis Lam. Essential Oil

Abstract The chemical analysis of the Salvia amplexicaulis Lam. herb essential oil was performed using GC-FID and GC/MS. Fifty-one compounds (90.2% of the total oil) were identified. The oil was characterized by a high amount of sesquiterpenes (81.1%), with germacrene D (14.8%), viridiflorol (10.6%), caryophyllene oxide (10.5%), and β-caryophyllene (9.4%) being the main components. The microbial growth inhibitory properties of the oil was determined against Gram-positive bacteria Staphylococcus aureus, St. epidermidis, Micrococcus luteus Gram-negative bacteria Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli and a yeast Candida albicans. The best inhibitory effect was detected against M. luteus followed by the effects against St. epidermidis, St. aureus and C. albicans. Tested Gram-negative bacteria were more resistant than Gram-positive bacteria and C. albicans.
Soumission chimique : approches pratiques en toxicologie médico-légale

De facon cyclique, la presse ecrite met en garde ses lecteurs face a l'effet deletere de la consommation de substances psycho-actives, ajoutees a leur insu. Ces produits sont soit des medicaments detournes de leur usage (flunitrazepam, GHB), soit des stupefiants (cannabis, ecstasy, LSD) ou encore, plus simplement de l'alcool ethylique. La medecine legale peut se retrouver impliquee dans la caracterisation de l'usage de ces substances dans le cadre de la soumission chimique. L'expert en toxicologie peut voir sa tâche rendue difficile par des prelevements tardifs, des substances a rechercher tres faiblement dosees et une interpretation delicate et compliquee, en particulier avec le GHB. L'objet de ce manuscrit est de proposer une ligne de conduite en matiere d'investigations toxicologiques dans les cas de soumission chimique.
Towards an understanding of the high productivity of rice with System of Rice Intensification (SRI) management from the perspectives of soil and plant physiological processes

The System of Rice Intensification (SRI) is based on a set of practices such as transplanting young seedlings and aerobic soil management during the vegetative stage without using costly external input, which attracted rice researchers because of higher yields compared with conventional flooded practices. This review assesses some field data for SRI performance in light of current knowledge about certain agronomic practices, focusing particularly on nitrate production in aerobic paddy soil and the possible effect of differences in nitrate uptake on rice growth, as this could help explain some part of rice performance with SRI. Aerobic soil environments realized with SRI management might be favorable for nitrification as well as for the expansion of rhizosphere area, which could enhance nitrate uptake and boost the yield potential of rice. The effect of nitrate uptake and assimilation under SRI practice on dry matter production should be studied comprehensively to explore the possibility of breaking the yield ceiling of rice.
Microstructure and properties of novel SPEEK/PVDF-g-PSSA blends for proton exchange membrane with improved compatibility

Novel blend membranes of poly(vinylidene fluoride) grafted poly(styrene sulfonic acid) (PVDF-g-PSSA) with sulfonated poly(ether ether ketone) (SPEEK) were fabricated for direct methanol fuel cell applications. The PVDF-g-PSSA copolymer can be homogeneously dispersed in the SPEEK matrix with a unique hierarchical particle surface. All the SPEEK/PVDF-g-PSSA blend membranes exhibit better dimensional stability, lower methanol permeability, higher selectivity than commercial Nafion® 117 at room temperature. Notably, at the PVDF-g-PSSA content of 5 wt%, the blend membrane exhibits the best overall membrane performance, which is supposed to benefit from the improved compatibility and strong interactions between the PVDF-g-PSSA and SPEEK matrix. The thermal stability and the temperature dependence of water uptake, dimensional change and proton conductivity of the blend membranes are also investigated. This study provides a promising strategy for the design and fabrication of high performance polymer electrolyte membrane by rational control of microstructure and compatibility of the blend membrane.
On the shattering of clusters by surface impact heating

The onset of a shattering regime when a supersonic cluster undergoes an ultrafast heating by its impact at a surface, proposed on the basis of an information theoretic analysis, has now been demonstrated experimentally for molecular clusters. It is emphasized that the sudden onset of shattering as a function of impact velocity is a robust result depending essentially only on the multitude of possible isomers of larger clusters. There is one underlying assumption of the information theoretic approach—namely that there is a rather rapid thermalization of the translational degrees of freedom of the impact heated cluster so that mean energy is the only energetic constraint. When this is not necessarily the case, e.g., for ionic clusters at lower energies, there will not be extensive fragmentation.
Comparison of Lead Extraction and Detection Procedures for Six Canadian Soils

The effects of acid digestion procedures and instrumentation on extracted lead (Pb) concentrations from several soils, including a mildly Pb-contaminated soil, were determined using a two-factor factorial experiment. The two factors were (i) digestion procedure [seven levels: U.S. EPA, AOAC (dry ashing), nitric acid (NA), three aqua regia procedures (AR1, AR2, and AR3), and hydrofluoric acid (HF)] and (ii) instrumentation [two levels: atomic absorption spectrometry (AAS) and inductively coupled plasma (ICP) spectroscopy]. The greatest Pb recovery was obtained when soils were digested with HF and analyzed by AAS. The results suggest that the AOAC procedure (a standard procedure for recovery of soil nutrients and trace elements in Canadian laboratories) and EPA procedure (a standard procedure in American laboratories) may underestimate Pb concentrations in some Atlantic Canadian soil types. The AAS procedure is more accurate than ICP for determining Pb concentrations in soil with a history of PbHAsO4, at least for Atlantic Canadian soils.
Rates and mechanism of the reactions of hydroxyl radicals with acetic, deuterated acetic, and propionic acids in the gas phase

Rate constants for the reactions of hydroxyl radicals with the monomer and dimer of acetic acid, deuterated acetic acids, and propionic acid have been determined by a laser photolysis-resonance absorption technique. Hydroxyl radicals were generated by photolysis of the acids at 222 nm with a KrCl laser and their decay was followed by time-resolved resonance absorption. The monomers of acetic and deuterated acetic acids reacted with OH much faster than the dimers, whereas the monomer and dimer of propionic acid reacted with about equal rate constants. A primary isotope effect was observed when carboxylic but not alkyl hydrogen was substituted by deuterium in acetic acid. The results are entirely consistent with the two-channel mechanism that we proposed for the reaction of OH with formic acid. The results are interpreted in terms of the variations in C-H bond strengths and in equilibrium constants for adduct formation of the acids studied.
Multistep Mechanism in the Electrochemical Oxidation-Reduction of Fe-Citrate Complexes

A study was made of the electrochemical behavior of the Fe-citrate system in aqueous medium using cyclic voltammetry. Potential sweeps between 200 and -650 mV us Ag/AgCl show the existence of two Fe(III)/Fe(II) redox systems. The first, with a half-wave potential close to 0 V, proves to be a reversible system, while the second, with a half-wave potential around -0.4 V, shows the characteristics of an E r C i process. Competitive reactions between hydroxy and citrate complexes of Fe(III) are considered. Both equilibrium measurements and kinetic evolution of the system are used in order to propose a scheme for the set of chemical and electrode rections studied
Recent advances in understanding metal dusting: A review

Recent experimental investigations have widened the understanding of metal dusting significantly. Microscopic observations have been used to dissect dusting mechanisms. Iron dusts by growing a cementite surface scale, which catalyses graphite nucleation and growth. The resulting volume expansion leads to cementite disintegration. Cementite formation on iron can be suppressed by alloying with germanium. Nonetheless, dusting occurs via the direct growth of graphite into the metal, producing nanoparticles of ferrite. This process is faster, because carbon diffusion is more rapid in α‐Fe than in Fe3C. Austenitic materials cannot form cementite, and dust via formation of graphite at external surfaces and interior grain boundaries. The coke deposit consists of carbon nanotubes with austenite particles at their tips, or graphite particles encapsulating austenite. TEM studies demonstrate the inward growth of graphite within the metal interior. It is therefore concluded that the dusting mechanism of austenitic materials like high alloy Cr–Ni steels and Ni base materials is one of graphite nucleation and growth within the near surface metal. In all alloys examined, both ferritic and austenitic, the principal mass transfer process is inward diffusion of carbon. Alloying iron with nickel leads to a transformation from one mechanism with carbide formation to the other without. Copper alloying in nickel and high nickel content stainless steels strongly suppresses graphite nucleation, as does also an intermetallic Ni–Sn phase, thereby reducing greatly the overall dusting rate. A surface layer of intermetallic Ni–Sn Fe‐base materials facilitates the formation of a Fe3SnC surface scale which also prevents coking and metal dusting. Current understanding of the roles of temperature, gas composition and surface oxides on dusting rates are summarised. Finally, protection against metal dusting by coatings is discussed in terms of their effects on catalysis of carbon deposition, and on protective oxide formation.
Solubilities of silicon and of germanium in liquid lithium. Lithium–germanium partial phase diagram

The solubilities of silicon (0.00 ⩽xSi⩽ 0.0165) and of germanium (0.00 ⩽xGe⩽ 0.0872) in liquid lithium have been determined by equilibrium resistivity methods and can be represented, in part, by the equations ln xSi= 5.548 – 6775/T 500 ⩽T/K ⩽ 700 ln xGe= 5.459 – 6630/T 530 ⩽T/K ⩽ 715. A thermochemical cycle is used to derive solvation enthalpies (for the neutral gaseous species) for silicon (–557 kJ mol–1) and for germanium (–490 kJ mol–1) in liquid lithium. The compounds Li22Si5 and Li22Ge5 have been shown to precipitate from dilute solutions of silicon and of germanium in liquid lithium, respectively. The melting point of Li22Ge5(934 K) and the lithium-rich eutectic horizontal (453.5 K) of the lithium–germanium system have been established by d.t.a. and t.a. techniques, respectively. These results, together with the solubility data, have been used to augment the lithium–germanium phase diagram (0.00 ⩽xGe⩽ 0.20).
Effects of Ligation and Folding on Reduction Potentials of Heme Proteins

Ferrocytochrome c (Fe(II)cyt c) is ∼10 kcal/mol (410 meV) more stable toward unfolding than Fe(III)cyt c, owing mainly to the stabilization of the ferroheme by hydrophobic encapsulation and enhanced iron−methionine bonding. To determine the magnitudes of these two components, we have measured the binding constants of N-acetylmethionine (AcMet) and imidazole to ferric and ferrous N-acetylmicroperoxidase-8 (AcMP8), a heme-containing proteolytic fragment of cyt c. Our results show that the AcMet affinity of the heme significantly increases upon reduction, as confirmed by electrochemical measurements, and this increase accounts for 130 meV of the 410-meV stability difference between Fe(II)- and Fe(III)cyt c. A 240-mV upshift in reduction potential in the folded protein is attributed mainly to water exclusion from the heme environment, based on an analysis of the potentials of eight structurally characterized c-type cytochromes. Our analysis shows that the potentials of heme proteins can be tuned by roughly 50.
Effect of Different Wheat Classes and Their Flour Milling Streams on Textural Properties of Flour Tortillas

ABSTRACT Wheat flour tortillas were made from flour streams of three wheat cultivars: Jagger hard red winter wheat, 4AT-9900 hard white winter wheat, and Ernie soft red winter wheat. Wheat samples were milled on a Miag experimental mill. Twelve flour streams and one straight-grade flour were obtained. Tortillas were made from each flour stream and the straightgrade flour by the hot-press method. Tortilla stretchability and foldability were evaluated by a texture analyzer and six panelists, respectively. Flour protein and water absorption affected tortilla texture. The foldability evaluated by panelists was positively correlated with flour protein content, farinograph water absorption, and damaged starch (P < 0.05). The 2BK and 3BK streams of hard wheat produced tortillas with strong stretchability and good foldability. Middling streams of hard wheat yielded tortillas with lighter color and less stretchability. Under the conditions tested in this study, soft wheat flours were not good for producing flour t.
Ultrawide‐Band Unidirectional Surface Plasmon Polariton Launchers

Plasmonic devices and circuits, bridging the gap between integrated photonic and microelectronic technology, are promising candidates to realize on-chip ultrawide-band and ultrahigh-speed information processing. Unfortunately, the wideband surface plasmon source, one of the most important core components of integrated plasmonic circuits, is still unavailable up to now. This has seriously restricted the practical applications of plasmonic circuits. Here, we report an ultrawide-band unidirectional surface plasmon polariton launcher with high launching efficiency ratio and large extinction ratio, realized by combining plasmonic bandgap engineering and linear interference effect. This device offers excellent performances over an ultrabroad wavelength range from 690 to 900 nm, together with a high average launching efficiency ratio of 1.25, large average extinction ratio of 30 dB, and ultracompact lateral dimension of less than 4 um. Compared with previous reports, the operating bandwidth is enlarged 210 folds, while the largest launching efficiency ratio, largest extinction ratio, and small feature size are maintained simultaneously. This provides a strategy for constructing on-chip surface plasmon source, and also paving the way for the study of integrated plasmonic circuits.
The Effect of Using a Heating Tube in an Existing Spouted Bed Superheated Steam Dryer

Interest in the use of biofuels, such as pellets and briquettes, has continued to grow in the European market in recent years. In order to manage the increased use of biofuels, the dryer capacity must also increase. One possible way of accomplishing this is to install heating tubes into the already existing dryers. Therefore, industrially relevant and appropriate design data, such as energy efficiency and a possible increase in the capacity of developing drying systems, are needed. This article presents the experimental results obtained from drying sawdust in a continuous spouted bed using a heating tube submerged in the bed; the results are compared with those obtained from a bed without using a heating tube. Superheated steam is used as the drying gas in all tests. The drying test is performed with an almost constant inlet moisture content and at three different inlet and outlet temperatures. The drying efficiency increases when the heating tube is turned on. Some explanations of the relation between inlet and outlet gas temperature and moisture content are presented.
Dynamic effects of pair correlation functions on spin relaxation by translational diffusion in liquids

It is shown how the equilibrium pair correlation function between spin‐bearing molecules in liquids may be incorporated as an effective force in the relative diffusion expressions, and how one may solve for the resulting time correlation functions and spectral densities needed for studies of spin relaxation by translational diffusion. The use of finite difference methods permits the solution no matter how complex the form of the pair correlation function (pcf) utilized. In particular, a Percus–Yevick pcf as well as one corrected from computer dynamics, both for hard spheres, are utilized. Good agreement with the experiments of Harmon and Muller on dipolar relaxation in liquid ethane is obtained from this analysis. Effects of ionic interactions in electrolyte solutions upon dipolar relaxation are also obtained in terms of Debye–Huckel theory for the pcf. Analytic solutions are given which are appropriate for the proper boundary‐value problem for the relative diffusion of molecules (i.e., a distance of mini.