Miracle-dz/UniFAR-FTUs huggingface dataset:
A small angle neutron scattering study of the lamellar and nematic phases of caesium pentadecafluoro-octanoate (CsPFO)/2H2O and CsPFO/CsCl/2H2O

The binary lyotropic liquid crystalline system caesium pentadecafluoro-octanoate (CsPFO)/water ( 2 H 2 O) exhibits an isotropic micellar phase, a lyotropic nematic phase and a positionally ordered, lamellar phase whose planes contain substantial water filled defects. It has been suggested that the structural unit in all three phases is a disk shaped micelle which, as temperature is lowered, first become orientationally ordered and then positionally ordered onto planes. Increasing the surfactant concentration apparently causes the micelles to first increase in size and then decrease, explained by invoking an attractive inter-micellar interaction. In this small angle neutron scattering study, we present further results on the strucutre of the binary and the ternary systems, the latter containing added electrolyte. Our results call into question the previously prposed model of the lamellar phase and show that the form of the temperature dependence of the aggregate dimensions depends on the structural model that has been adopted. We show that a much more satisfactory picture of the lamellar phase is obtained if the shape of the aggregates is assumed to consist of continuous amphiphile layers pierced by irregular water filled holes; increasing the CsPFO concentration then causes the amphiphile aggregates to grow. This structure is confirmed by the effect of adding electrolyte (CsCl) to the lamellar phase. Here, scattering shows explicitly that the water filled holes anneal out. The addition of electrolyte is also shown to cause changes of aggregate shape in the nematic phase. These changes in both binary and ternary systems are shown to be attributable to modifications of the intra-aggregate electrostatic head-group interactions
Impacts of tetrakis-hydroxymethyl phosphonium sulfate (THPS) based biocides on the functional group activities of some oil field microorganisms associated with corrosion and souring.

Aim: To determine the biocidal efficacy of THPS based biocides currently used in oil fields to control souring and corrosion. Methodology: By direct monitoring of inhibition of cell growth and inhibition of microbial functional group activities such as the ability to reduce sulfate and generate sulfide by sulfate reducing bacteria (SRB), reduce nitrate to nitrite by heterotrophic nitrate reducing bacteria (hNRB) and oxidation of sulfide and reduction of nitrate by sulfide oxidizing, nitrate reducing bacteria( so-NRB) using CSB-K medium. Results: We observed that higher doses of THPS (>400 ppm) was required to considerably inhibit the ability of SRB to reduce sulfate and generate hydrogen sulfide. It was also observed that the activities of SRB were more affected by the THPS biocides than those of hNRB and so-NRB. Conclusion: We conclude that SRB may have developed low level microbial resistance to THPS based biocides as higher doses are required to inhibit their activities. It is therefore recommended that THPS should be used in combination with other biocides or metabolic inhibitors for it to be effective at lower concentrations.
A numerical model for sulfur chemistry in warm‐frontal rainbands

A two-dimensional kinematic model of warm-frontal precipitation has been employed to model the sulfur chemistry of warm-frontal rainbands. Analysis of the model results indicates that nucleation scavenging, in-solution oxidation of SO2, and impaction of particulate sulfate by hydrometeors all contribute significantly to wet sulfate deposition, with nucleation scavenging generally the most important process. The model results also indicate that, in general, sulfate deposition will be a nonlinear function of the initial amount of sulfur species. Model predictions of sulfate concentrations in rain from warm-frontal rainbands and the variability of these concentrations within individual rain events are in accord with observations.
Multi-element atmospheric deposition study in Croatia

For the first time the moss biomonitoring technique and two complementary analytical techniques − neutron activation analyses (NAA) and atomic absorption spectrometry (AAS) − were applied to study multi-element atmospheric deposition in the Republic of Croatia. Moss samples were collected during the summer of 2006 from 98 sites evenly distributed over the country. Sampling was performed in accordance with the LRTAP Convention - ICP Vegetation protocol and sampling strategy of the European Programme on Biomonitoring of Heavy Metal Atmospheric Deposition. Conventional and epithermal NAA and AAS made it possible to determine concentrations of 41 elements including key toxic metals such as Pb, Cd, Hg, and Cu. Factor analysis (Principal component analysis with varimax rotation) was applied to distinguish elements mainly of anthropogenic origin from those predominantly originating from natural sources. Geographical distribution maps of the elements over the sampled territory were constructed using GIS technology. For the elements included in the European programme, the median values for Croatia were generally around the average median values observed in Europe. The Adriatic coastline of Croatia may be considered as an environmentally pristine area. This study was conducted in order to provide a reliable assessment of air quality throughout Croatia and to produce information needed for better identification of pollution sources and improving the potential for assessing environmental and health risks in Croatia associated with toxic metals.
Modelling intercrop management impact on runoff and erosion in a continuous maize cropping system: Part I. Model description, global sensitivity analysis and Bayesian estimation of parameter identifiability

In order to evaluate the long‐term impact of intercrop management on runoff and erosion in a continuous maize cropping system a new model was developed, based on the continuous plot‐scale runoff model of Laloy & Bielders (2008) . This model is called the Continuous Runoff and Erosion Hillslope model with DYnamic soil Surface properties (CREHDYS). This paper details the erosion and crop growth and decay model components and presents a thorough global variance‐based sensitivity analysis (GSA) with regard to the erosion prediction, followed by a Bayesian parameter identifiability assessment. As compared with the classical local univariate sensitivity analysis, a GSA is able to deal with the typical non‐linearity of process‐based hydrological and erosion models. The most influential parameters were the Manning's roughness coefficient followed by the saturated hydraulic conductivity of wheel track cells and the median particle size of the material. The soil aggregate stability and soil‐cohesion parameters were found to be almost non‐influential. Most of the results of the parameter identifiability procedure were in close agreement with the GSA. Indeed, the parameter uncertainty seemed to be proportional to the degree of influence, with Manning's coefficient being the most precisely identified, whereas soil and wheel track cohesion parameters showed the largest uncertainty. Exceptions were the soil aggregate stability and the Green‐Ampt soil matric potential. The uncertainty associated with the former was surprisingly low given its low level of influence whereas the uncertainty associated with the latter is partially explained by its negative correlation with the soil saturated hydraulic conductivities of overland flow and wheel track cells.
A Thermal Conductivity Model for Nanofluids Heat Transfer Enhancement

Nanofluids may be used for better cooling of drilling bits, especially poly crystalline diamond compact bits, which are very temperature sensitive. The study on the modeling of energy transport in nanofluids divided the heat transfer in nanofluids into two portions—heat transferred by stationary particles and heat transferred by moving particles. The authors studied each portion together. An equation for the thermal conductivity of nanofluids was developed based on the nanolayer thickness, Brownian Motion, and the size distribution of the nanoparticles. The expression developed successfully explained the enhanced thermal conductivity of nanofluids and led to some important conclusions. The authors investigated the size distribution of nanoparticles, which has been suggested to be an important factor and it gave satisfactory results. The values of the thermal conductivity for CuO/water and TiO2/water nanofluids were calculated using the expression developed from this study and they agreed very well with published experimental data.
Study of acid milk coagulation by an optical method using light reflection

Summary A turbidimetric method, based on light reflection, was used to study acid coagulation of reconstituted skim milk at low temperature. Capillary viscosimetry, gelograph and laser granulometer techniques were also employed. Acidification of milk was produced by hydrolysis of glucono-δ-lactone. The general shape of the turbidimetric signal as a function of pH or time can be divided into three stages: a lag phase followed by a significant decrease and then a final rise. Two factors have a great influence on the development of milk turbidity, pH and temperature. Dynamic viscosity measurements can be related to the turbidimetric signal while laser granulometrie measurements cannot be correlated with changes in turbidity: the micelle size distribution remains constant until the first signs of gelation. As previous work showed, dynamic viscosity diminishes with acidification until a particular pH is reached (pH 5·9 at 15°C and pH 5·75 at 20°C). We have related this latter period to the turbidimetric lag phase. As milk turbidity became lower than its initial value (pH 5·75 at 15°C and pH 5·55 at 20°C), dynamic viscosity increased significantly. The release of material from micelles (β-casein and Ca) could explain this phenomenon. In the same way, further increase of turbidity at a particular pH value (pH 5·3 at both 15 and 20°C) coulcl be partly due to the reincorporation of soluble casein monomers in the micelle framework. As the onset of gelation was approached, turbidity still increased as a result of gel network formation.
De-bittering of kinnow juice

their deep gratitude to Dr. RK Director, ICAR-CIPHET, Ludhiana, for his abiding interest and unending support for conducting the studies and encouraging compiling the information on feasibility of getting de-bittered kinnow juice in the form of technical bulletin. Financial support in the form of approved institutional research project (IXX10191) and for publishing this bulletin by ICAR is deeply acknowledged. Thanks are also to all those who have directly or indirectly associated with the research work
INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS

A system of instrumental neutron activation analysis in which no chemical operations are employed is described. It consists of neutron activation followed by gamma -ray spectrometry. Even with the relatively low thermal neutron flux available from a Van de Graaff accelerator photoneutron source (10/ sup 8/ neutrons sec/sup -1/ cm/sup -2/), useful analyses were carried out for more than 25 elements, in many cases with sensitivities in the parts-per-million range. In general, the method is much faster than chemical or spectroscopic methods of equal sensitivity and accuracy; it is nondestructive and is relatively free of serious interferences. No sample preparation is involved. Activation plus counting total only about 10 minutes per sample. (auth)
Conceptions of second year university students of some fundamental notions in chemistry

This research is a follow‐up to our earlier study in which we assessed the knowledge and conceptions of fundamental notions in chemistry of first year undergraduate students at the time of entry into university. It examines to what extent, after one year of study at university level, the conceptions of the students have evolved and how their knowledge of scientific theory has progressed. We have found that the conceptions of the students are often modified in the right way, but sometimes in the wrong way as well, and the results obtained seem to indicate that the ambitious aim of teaching (better acquisition of important notions by students) is far from being attained. The study also shows that for some notions the teaching of chemistry has too formal a character. To rectify this situation, we propose that practical work must include problems that are not only chemical in nature.
Productive sugar isomerization with highly active Sn in dealuminated β zeolites

A water-tolerant Lewis acid catalyst was synthesized by grafting SnIV in isopropanol under reflux onto dealuminated zeolites with the BEA (β) topology. This synthesis method allows the production of highly active Snβ-type catalysts without the need for long hydrothermal syntheses or hydrogen fluoride, while using cheap Sn-precursors, industrially available β zeolites and standard catalyst synthesis unit operations. Extensive characterization of the best catalyst shows highly dispersed Sn in the zeolite matrix (XRD, 29Si MAS NMR and 1H MAS NMR) without the formation of SnO2 (XRD and UV-Vis). The catalyst was tested for the model isomerization of sugars such as glucose to fructose. The catalytic activity proved to be purely heterogeneous and the catalyst was recycled and reused without significant loss in activity. Isomerization productivities above 4 kg product per kg of catalyst per hour are reported with appreciably low Sn loadings, corresponding to exceptionally high turnover frequencies, viz. 500 cycles per Sn per hour at 110 °C, which surpass the activity per Sn of the original hydrothermally synthesized Snβ.
Measurement of Cracking Kinetics of Pure Model Compounds by Thermogravimetric Analysis

Determination of cracking kinetics by thermogravimetric analysis (TGA) is attractive but requires careful experimental design to ensure consistent results. Here, we examine three methods for determining kinetic parameters by TGA: differential analysis at a constant heating rate (differential), temperature for constant conversion at multiple heating rates (isoconversional), and maximum rate at multiple heating rates (peak temperature). The test compounds used in this study are based on pyrene, with boiling points high enough that mass loss was dominated by the reaction rather than evaporation. The methods using multiple heating rates gave comparable results to each other but were very different from the results from the differential method. The results of the differential method were insensitive to the heating rate and consistent with kinetics of cracking reported in the literature for similar structures. The differential analysis method for cracking of model compounds was the best approach, because the me.
ROOT DISTRIBUTION, WATER USE, AND NUTRIENT UPTAKE OF MILLET AND GRAIN SORGHUM ON WEST AFRICAN SOILS

Field experiments were carried out in three Sahelian agroecosystems (Kala Pate, N'Dounga, and Chikal) to compare the rooting systems and water and nutrient extraction of millet and sorghum under different levels of water, fertilization, and plant density. Initial soil moisture content was so low (<0.04 m3 m-3) that crop rooting was limited by the maximum depth of the wetting front. Soil acidity (pH 4.5) and aluminum and manganese toxicities reduced the effective crop rooting depth to less than 45 cm at Kala Pate. Millet utilized water more efficiently under less favorable soil conditions, but in most cases it extracted less nutrients and utilized rainfall less efficiently than sorghum. Results from this study suggest that root penetration of both crops was controlled by the seasonal wetting front and soil pH. These factors were most limiting for efficient nutrient and water use. Inputs of water and fertilizer significantly increased rainfall use efficiency and nutrient uptake by both crops.
Catalytic Activity of the Rh Surface Oxide: CO Oxidation over Rh(111) under Realistic Conditions

Using a combination of surface X-ray diffraction and mass spectrometry at realistic pressures, the CO oxidation reactivity of a Rh(111) model catalyst has been studied in conjunction with the surface structure. The measurements show that a specific thin surface oxide is always present in the high activity regime of Rh-based CO oxidation.
A surface plasmon resonance immunosensor for human growth hormone based on fragmented antibodies

An SPR-based immunosensor for human growth hormone (hGH) is reported. It is based on the application of fragments of antibodies against human growth hormone (anti-hGH). The native thiol groups of anti-hGH were liberated by splitting the intact anti-hGH antibody using the reducing agent 2-mercaptoethylamine (2-MEA) into two half-sized fragments (frag-anti-hGH) while retaining active antigen-binding sites. Afterwards frag-anti-hGH were immobilised on the gold film of the SPR-chip by chemisorption. The antibody and 2-MEA concentrations have been optimized with respect to the performance of the immunosensor. The surface morphology of the immunosensor was studied by atomic force microscopy. The binding of hGH to the sensor surface is highly specific, and the respective immunosensor has a limit of detection of 0.0034 μM of hGH. Good repeatability of the analytical signal and selectivity over porcine growth hormone are demonstrated. The sensor has relatively good operational stability, which was satisfactory within 18 days.
Analysis of the surface chemistry of oxidized polyethylene: comparison of XPS and ToF‐SIMS

A series of low‐density polyethylene (LDPE) surfaces, chemically modified using a number of oxidative techniques employed for adhesion enhancement (pretreatments), have been studied by time‐of‐flight (ToF) SIMS and XPS. The methods consisted of corona discharge, flame, electrochemical, chromic acid, acid dichromate and acid permanganate treatment. All except flame treatment were performed under mild and fairly severe conditions to yield a range of surface chemistries. The XPS analysis, using high energy resolution and a refined approach to C 1s curve‐fitting, provided some new insights into the quantitative assessment of the type and concentration of functional groups. Both positive and negative ion ToF‐SIMS spectra were obtained at high mass resolution. The oxygen‐containing fragments were identified by accurate mass analysis and subjected to a detailed comparison with the XPS results. No convincing relative intensity correlations could be identified that would allow particular secondary ion fragments to be associated strongly with particular functional groups (in this multi‐functional surface situation). Inorganic residues resulting from wet chemical treatments were also investigated and here the two techniques were found to be more complementary. Copyright © 2003 John Wiley & Sons, Ltd.
NMR imaging and differential scanning calorimetry study on drying of pine, birch, and reed pulps and their mixtures

Drying, water fractions, and water distribution were investigated for pine, birch, and reed pulps and pine–birch, pine–reed, and pine–birch–reed pulp mixtures. Gravimetrically determined drying times showed that the drying rates of the pulps decreased at two to four inflection points. Characterizations of the dried pulps by differential scanning calorimetry (DSC) showed a faster removal of free water than freezing and nonfreezing bound waters; all decreased simultaneously, however. DSC also revealed the critical water contents at which the free water and freezing bound water disappeared. The gravimetrically determined inflection points of the drying curves corresponded with the critical points determined by DSC. NMR line widths and images produced by 1H-NMR imaging revealed the nature and regions of the pulp drying. The constant growth rate of the NMR line widths with decreasing water content appeared to change at two inflection points, which fell approximately in the same water content regions as the inflection points of the drying curves. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 937–945, 2006
Short-Term Impacts of Gray Water Irrigation on Soil Characteristics in Land-Treatment Vegetation Filters

This study on soil quality parameters was conducted from December 2008 to July 2010 to see the short-term impacts of gray water irrigation on physical and chemical properties of soil. The results envisaged slight positive impacts of wastewater irrigation on upper soil layers (0–30 cm) with an increase in soil organic matter (SOM) from 1.45% to 1.89% and nutrient content increases from 199 to 267 kg ha−1 nitrogen (N), from 12.4 to 27.1 kg ha−1 phosphorus (P), and from 131 to 136 kg ha−1 potassium (K). Slight changes were also recorded in the soil pH and electrical conductivity (EC), which increased from 6.39 to 6.81 and 145 to 229 μS cm−1 respectively, in the upper soil layers. The soil bulk density (BD) slightly decreased to 1.34 g cm3 in the treatment plot from 1.45 g cm3 at the commencement of the trial, which indicates good soil conditioning under the gray water irrigation trial.
Die phloroglucide von neun dryopteris-arten aus kenya sowie der d. oligodonta (desv.) pic.-serm. und d. “dilatata” von den canarischen inseln

Among the eight species of the fern genus Dryopteris which have been recorded from Kenya (East Africa), the group of D. inacqualis, D. pentheri and D. schimperana is regarded as critical. There is no agreement among experts as to whether D. inaequalis s. str. is restricted to South Africa and whether it should be separated specifically from D. pentheri Chemical and, as far as possible, cytological investigations of available material showed that the following taxa of Dryopteris occur in Kenya (ploidy in brackets) : 1. D. athamantica (2 × );2. D. callolepis (4 × ); 3. D. inaequalis (4 × ); 4. D. kilenzensis (2 × ); 5. D. manniana (4 × ); 6. D. pentheri (2 × ); 7. D. schimperana (2 × ); 8. D. sp. RBF-71/885 (TR-330.5) (4 × ); 9. D. squamiseta(ploidy not determined). The nomenclature of the four critical taxa, 3, 6, 7 and 8 is provisional. For comparison, two taxa from the Canary Islands, 10. D. ‘dilatata’ (4 × ) and 11. D. oligodonta (2 × ) were also investigated. Among the nine taxa from Kcnya, two (4 and 9) did not contain any phloroglucides. Dryopteris kilomensis must be regarded as one of the few representatives of the genus Dryopteris which lacks such compounds. On the other hand, the negative result for 9 is in agreement with the fact that this species has recently been transferred to a new genus Nothopevanema. The following three new compounds havc been isolated: Trisaspidinol (8), from D. inaequalis; Pentherin-I (not quitc pure) and Pentherin-I1 (hypothetical partial formula 25), from D. pentheri. Pentherin-I is also present in D. sp. RBF-71/885. Chemical and cytological results are compatiblc with the hypothesis that the latter is an allotetraploid derived from the diploids 6 and 7. The chemical patterns of 6, 7 and 8 show similarities to that of D. manniana, which in turn also shows similarities to the European D. filix-mas. Dryopteris ‘dilatata’ from the Canary Islands is chemically different from Europcan D. dilatata s. str. in lacking para-aspidin, while D. oligodonta gave results rather different from D. inaequalis or other East African species, and also from known European taxa.