Miracle-dz/UniFAR-FTUs huggingface dataset:
Kinetic Studies on Sorption of Textile Dyes Using Lamina and Petiole Parts of Eichhornia crassipes

Sorption capacity of two different parts of Eichhornia crassipes such as Lamina and Petiole on a Basic dye (Basic Aurophine-O), Acidic dye (Acid Fast Red-A) and Reactive dye (Brill Red-5B) was studied in a batch system. The maximum equilibrium uptake capacity of petiole was 25.5 mg/g for Basic Aurophine-O, 23.1 mg/g for Acid Fast Red-A and 0.18 mg/g for Brill Red-5B. The equilibrium uptake capacity of petiole was found to be more in Basic Aurophine-O dye when compared to all other dyes studied. The maximum equilibrium uptake capacity of lamina was 27.0 mg/g for Basic Aurophine-O, 25.2 mg/g for Acid Fast Red-A and 4.2 mg/g for Brill Red-5B. The equilibrium uptake capacity of lamina was found to be more in Basic Aurophine-O when compared to Brill Red-5B and Acid Fast Red-A dyes studied in the present investigation. From the result, it was observed that the uptake capacity of dyes using E. crassipes part Lamina was found to be more when compared to the other E. crassipes part of Petiole used in the present study. Sorption results were found to be fitted very well with the Pseudo-second order kinetic model when compared to Pseudo-first order kinetic model. The intra particle diffusion coefficient (Ki) and diffusion coefficient (Di) obtained for the removal of dyes studied using Lamina was found to be more when compared to the other part of Petiole. The polynomial equations are developed and can be used as a ready reckoner equation to find out the percentage color removal of dyes studied in the present investigation at different period of time intervals.
Total and Soluble Metal Contents in Flux-Cored Arc Welding Fumes

The chemical composition and solubility of metals in welding fumes is thought to be related to the welder health but is not well characterized. We quantified and compared the total (insoluble + soluble) and soluble metal contents in fumes from flux-cored arc welding using non-stainless steel (FCAW/NSS) and stainless steel (FCAW/SS) wire. Welding was performed in an American Welding Society standard fume collection chamber. The total content of 13 analyzed metals was significantly higher in FCAW/NSS fumes than in FCAW/SS fumes (51.6 ± 5.7 vs. 40.2 ± 5.2%, p < 0.001). Soluble metal content was significantly higher in FCAW/SS fumes than in FCAW/NSS fumes (15.5 ± 5.8 vs. 6.49 ± 2.4%, p < 0.001) due to the presence of potassium and sodium. Different proportions of each element were observed between welding types. Iron, magnesium, and aluminum were significantly higher in FCAW/NSS fumes, whereas chromium, nickel, and potassium were more common in FCAW/SS fumes. The metal composition of FCAW fumes was more similar to that of shielded metal arc welding fumes than that of gas metal arc welding fumes. It seems unnecessary to measure soluble iron, nickel, aluminum, and barium to compare with their soluble ACGIH-TLVs at the FCAW welding process. But chromium should be specified in terms of its valance and solubility.
Rational Co‐Immobilization of Bi‐Enzyme Cascades on Porous Supports and their Applications in Bio‐Redox Reactions with In Situ Recycling of Soluble Cofactors

In bio‐redox cascade reactions that are immobilized on porous supports, mass‐transfer limitations may impede the effective concentration of the cofactor around the corresponding dehydrogenases. This main drawback has been addressed by the co‐immobilization of both the main and recycling dehydrogenases. Herein, we report tailor‐made co‐immobilization procedures to assemble three different bio‐redox orthogonal cascades in vitro (two selective reductions and one selective oxidation) with in situ cofactor‐regeneration. However, the co‐immobilization itself does not guarantee the success of the biotransformation because the same co‐immobilization chemistry may not be suitable for the two enzymes that are involved in the bio‐redox cascade. Therefore, our co‐immobilization system was optimized for each bi‐enzymatic cascade. In all cases, the optimized co‐immobilization procedure was more efficient in the biocatalytic cascade than if the two dehydrogenases were immobilized on two different carriers. In one specific case (one thermophilic cascade), the co‐immobilization of an optimal ratio of main/recycling dehydrogenases (1:5) on the same carrier resulted in a biocatalyst that was able to recycle NADH up to 9000 times per equivalent of substrate in 1 hour at 55 °C. Moreover, uniform distributions of both dehydrogenases across the porous surface also enhanced the recycling efficiency of the cofactor 1.5‐fold versus cascades in which the enzymes were not uniformly distributed across the same porous surface, presumably because of vicinal cooperation effects. Hence, this system for the co‐immobilization of bi‐enzymatic systems may be extended to other biocatalytic cascades, thereby opening a window for the optimization of other multi‐enzyme biotransformations in which cofactor‐recycling is necessary.
Diversity‐Oriented Synthesis through Rh‐Catalyzed Selective Transformations of a Novel Multirole Directing Group

In the context of transition‐metal‐catalyzed CH functionalization, directing‐group strategy was developed for the improvement of chemical reactivity and selectivity. Recently, to avoid the inherent limitations of traditional mono‐role directing groups, a dual‐role oxidizing‐directing‐group strategy was developed, in which the directing group acts both as directing group and oxidant. Herein, we report a multirole directing group, which possesses multiple reactive sites, exhibits unique reactivity and selectivity, and leads to four different types of products from a single starting material through rhodium‐catalyzed CH activation/alkyne annulation reactions. The excellent product diversity and regio‐ and redox selectivity were well controlled by the tuning of solvents and oxidants.
DISCRETE FOURIER TRANSFORM CONVOLUTED DENSITOMETRIC PEAK RESPONSES FOR THE DETERMINATION OF METHOCARBAMOL IN DIFFERENT PHARMACEUTICAL MIXTURES IN THE PRESENCE OF ITS DEGRADATION PRODUCT

Application of chemometrics to the handling of the HPTLC-densitometric response-distance data was used for the determination of methocarbamol in different pharmaceutical mixtures in the presence of its degradation product. The chemometric treatment of the data involves the development of the derivative spectra of the HPTLC-densitometric response-distance data obtained from the separated peaks of three ternary mixtures of methocarbamol and ibuprofen, paracetamol or diclofenac in the presence of Guaifenesin. It also involves the convolution of the derivative curves using 8-points sin xi polynomials (discrete Fourier functions). Chemometric treatment of the densitometric data resulted into the enhancement of the regression equation parameters as well as the enhancement of the accuracy and precision of the prepared synthetic mixtures of the studied drugs. This enhancement is more pronounced in the nonideal case (minor component analysis) where determination of trace amounts of the degradation product corresponding to less than 2% (the pharmacopeial limit) of the intact drug in presence of other mixtures components and background noise. All the proposed chemometric methods can be employed for the assay of the mixtures in their respective dosage forms with good recovery and were compared with HPLC method as a reference method.
Oxidation Kinetics of Water and Organic Compounds by Silver (II) Using a Potentiometric Method

A new experimental method using an electrochemical technique is presented for the study of the oxidation kinetics of water and organic compounds. The electrogeneration of silver (II) in 6 M nitric acid is presented. Good agreement is found between a theoretical model and the experimental results. Since the Ag(II)/Ag(I) system obeys Nernst's law, the potential of this couple can be followed as a function of time. This technique has been used to study the oxidation kinetics of water, formic acid, acetic acid, and urea by silver (II) in 6 M nitric acid. The reactions were found to be first order with respect to organic compounds. Oxidation kinetics of formic acid and acetic acid showed first order in silver (II) and that of urea was found to be second order in silver (II).
SBR System for Phosphorus Removal: ASM2 and Simplified Linear Model

An SBR (sequencing batch reactor) system was evaluated for nutrient removal. The system is capable of removing 95% of influent , or from 6.7 to 0.4 mg P/L, with the addition of acetate of 120-150 32 PO4 mg COD/L in the feed solution (primary effluent). Nitrification was also achieved within the preset aeration cycle time in reducing the effluent ammonia level from 16.3-19.8 mg N/L to 0.2-0.3 mg N/L. However, denitrification was incomplete due to a slower endogenous nitrate respiration rate in the idle period, resulting in an effluent nitrate level of 7-8 mg N/L. A linear version of the ASM2 (Activated Sludge Model No. 2) was developed to model the performance of an SBR system for nutrient removal. The developed model appropriately predicts the dynamic behavior of the SBR system with respect to phosphate release/uptake, nitrification, am- monification, and denitrification. Compared with the full ASM2, the calibration of model parameters and model simulation require less computational time for practical implementation of the linear model into a process control system for the SBR.
New PTFE-polyamide compounds

New PTFE-polyamide compounds produced by reactive extrusion show very good material and tribological properties combined with an excellent wear resistance. The basis of these properties is the formation of chemical bonds between PTFE and PA by transamidation in a melt modification reaction. The effective processing and the material properties of PA are combined with the excellent anti-friction properties of PTFE in this innovative material. Test specimen of PA and PA-PTFE obtained by two component injection moulding process show very high interfacial adhesion. The processability of this material on polymer processing equipment and the use of available materials favours the commercialisation of these new PTFE polyamide compounds.
Dynamic properties of heat‐treated butyl vulcanizates

Heat treatment of butyl rubber containing carbon black can considerably reduce “structure effects” in the dynamic properties of the vulcanizate, although swelling measurements indicate that G ∞ the shear modulus at very high amplitudes is unaltered. This paper compares the G′, G″ and phase angle δ changes that occur with the amplitude of oscillation for both a normal butyl rubber containing HAF black and a vulcanizate of the same composition but which has been subjected to an additional heat-treatment process with N-methyl-N, 4-dinitrosoanaline.
Facile synthesis and morphogenesis of superparamagnetic iron oxide nanoparticles for high-performance supercapacitor applications

A facile method has been developed for the synthesis of nearly mono-dispersed iron oxide nanocrystals. The structural analysis of the synthesized iron oxide nanocrystals reveals the magnetite phase of Fe3O4. The average particle size of the iron oxide was estimated to be 8 ± 2 nm. The observed particle size is in good correlation with the particle size estimated by magnetic measurements. Furthermore, these nanocrystals showed bi-functional ferromagnetic and superparamagnetic behavior below and above the blocking temperature, respectively. The potential use of these nanocrystals as an electrode for supercapacitors was examined by investigating the electrochemical behavior of iron oxide using cyclic voltammetry (CV) and galvanostatic charge–discharge tests. The CV characteristics of the iron oxide electrode showed a typical pseudocapacitive behavior in 3 M KOH solution. Moreover, the specific capacitance of 185 F g−1 at the current of 1 mA was observed with excellent cyclic stability, which is much higher than the reported value for iron oxide. The higher specific capacitance is due to the uniform nano-size of iron oxide. This work provides an ultimate facile method to synthesize nanostructured iron oxide for application in next generation energy storage materials.
Constraining the physics of carbon crystallization through pulsations of a massive DAV BPM37093

Abstract We are trying to reduce the largest uncertainties in using white dwarf stars as Galactic chronometers by understanding the details of carbon crystalliazation that currently result in a 1–2 Gyr uncertainty in the ages of the oldest white dwarf stars. We expect the coolest white dwarf stars to have crystallized interiors, but theory also predicts hotter white dwarf stars, if they are massive enough, will also have some core crystallization. BPM 37093 is the first discovered of only a handful of known massive white dwarf stars that are also pulsating DAV, or ZZ Ceti, variables. Our approach is to use the pulsations to constrain the core composition and amount of crystallization. Here we report our analysis of 4 hours of continuous time series spectroscopy of BPM 37093 with Gemini South combined with simultaneous time-series photometry from Mt. John (New Zealand), SAAO, PROMPT, and Complejo Astronomico El Leoncito (CASLEO, Argentina).
Improved antifouling properties of TiO2/PVDF nanocomposite membranes in UV‐coupled ultrafiltration

A polyvinylidene fluoride (PVDF) ultrafiltration (UF) membrane was modified by dispersing titanium oxide (TiO2) particles in a PVDF solution. PVDF flat-sheet membranes were prepared by a phase inversion method. This study investigates the potential low-fouling properties of these composite membranes during filtration, in darkness or under UV irradiation, of pure water and foulants representative of those found in membrane bioreactor processes: commercial bovine serum albumin (BSA) as a model protein and real soluble extracellular polymeric substances (EPS). The experimental results indicate that nanocomposite membrane has a structure with longer and larger macrovoid than neat PVDF membranes resulting in higher water flux performances. These higher flux performances were also due to an increase in surface hydrophilicity because of the presence of TiO2 particles. Moreover, such membranes are less prone to adsorption by BSA and present self-cleaning ability under static irradiation. During filtration of BSA and EPS without UV irradiation, nanocomposite membranes presented a little flux decline and reached stabilization more rapidly in comparison with PVDF membranes. Moreover, simultaneous UV irradiation during ultrafiltration has a benefit effect only on nanocomposite membranes for which initial flux was increased. Hydrophilic properties of nanocomposite membranes lead to better retention performances of BSA and EPS, which are still improved under UV irradiation. Finally, nanocomposite membranes under UV irradiation presented the best flux recovery ratio confirming their antifouling property. VC 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41731.
Influence of Potassium Fertilizer on Yield of Plantain Intercropped with Cassava on an Oxic Paleustalf in Southwestern Nigeria

Abstract There is very little literature on the influence of plantain–cassava intercropped on this soil type. Therefore, an experiment was conducted in 1993 and 1995 cropping seasons on the influence of potassium (K) fertilizer on the yield of the two crops on a soil classified as Oxic paleustalf (or Ferric Luvisol) in the rain forest agroecological zone of Nigeria. Four rates of K fertilizer (120, 240, 360, and 480 kg K ha−1) and control were evaluated on the yield and yield components of these two crops in sole and intercropping. The experimental design was a randomized complete block (RCBD) replicated four times. Results showed that the soil is acidic and the exchangeable cations contents were suboptimal when compared with the optimum required for a sustained cultivation of plantain. Furthermore, the plantain–cassava intercropped yields responded significantly (p<0.05) to fertilizer applied in terms of the yield and yield components of both crops in sole and intercropping. Highest bunch weight of plantain and tuber yield of cassava was recorded at 360 and 240 kg K ha−1 (taking the mean of both years). Potassium fertilizer after this point resulted in lower yields of both crops when intercropped.
Preparation and characteristics of photocrosslinkable hydrophilic polymer having cinnamate moiety

The reaction of copolymer of N,N-dimethylacrylamide (DMAA) and bromoethyl methacrylate with potassium cinnamate produced water-soluble photosensitive polymers. Photosensitive polyDMAA films were irradiated with a 400 W high-pressure mercury lamp (λ > 280 nm) to produce crosslinked polymers, which were swollen in water. The degree of swelling was controlled by the irradiation time and content of cinnamate moieties in copolymers. Higher cinnamoylation and longer irradiation time resulted in higher yield of crosslinked polymers and less swellability. Partial degelation upon irradiation at λ ∼ 254 nm was observed. The advantage of gelation via photodimerization over conventional chemical crosslinking methods is discussed in conjunction with biomedical applications. © 1992 John Wiley & Sons, Inc.
Fourier Transform Infrared Spectroscopic Investigation of the Binary and Ternary Cyanide Adducts of the Oxidized Horseradish Peroxidase: Identification of a Second Stretching Mode for the Carbon-Nitrogen Bond of the Bound Cyanide Ion

ABSTRACT The binary and ternary cyanide adducts of the ferric horseradish peroxidase were investigated by Fourier transform infrared spectroscopy. The carbon-nitrogen bond of the bound cyanide ion in the binary ferric cyanohorseradish peroxidase exhibits two stretching vibrations at 2130 cm−1 and 2127 cm−1 with the latter mode being observed in this work for the first time. This finding supports the results of the resonance Raman study of cyanohorseradish peroxidase, which identified two iron-carbon-nitrogen bending vibrations and two iron-carbon stretching vibrations, proving the existence of two conformational states. The identification of the latter carbon-nitrogen stretching frequency allowed the assignment of all of the vibrational modes of the iron-carbon-nitrogen groups of the two conformational states of the ferric cyanohorseradish peroxidase. The first conformer is characterized by a carbon-nitrogen stretch at 2130 cm−1, an iron-carbon stretch at 453 cm−1, and an iron-carbon-nitrogen bending mode at 405 cm−1. The second state has a carbon-nitrogen stretch at 2127 cm−1, an iron-carbon stretch at 360 cm−1, and an iron-carbon-nitrogen bending mode at 422 cm−1. The iron-carbon stretching band is weakly sensitive to pH changes, but it is sensitive to H2O/D2O substitution, indicating that the bound cyanide ion in cyanohorseradish peroxidase is hydrogen bonded to the surrounding protein. The two states were attributed to variation in the extent of hydrogen bonding of the iron-carbon-nitrogen groups in the two states. The carbon-nitrogen stretching vibrations of the ternary complexes of cyanohorseradish peroxidase with ferulic acid, benzamide, and benzhydroxamic acid have been investigated for the first time. The binding of the substrate to cyanohorseradish peroxidase does not always lead to the vanishing of one of the conformational states as in the carbon monoxide adducts of the ferrous horseradish peroxidase, but can cause shifts in the νC-N frequency and in the relative population of both conformational states.
Cationic polymerization of isobutyl vinyl ether in aqueous media: physical chemistry tricks to fight against thermal runaway

Cationic polymerization of isobutyl vinyl ether (IBVE) in aqueous media (suspension, dispersion or emulsion), using mainly BF3OEt2 as a co-initiator is reported. A high exotherm was observed while carrying out the polymerization in aqueous suspension, whereas in dispersion (mixture of water and n-hexane as reaction medium) or in emulsion particularly, efficient heat transfer decreased thermal runaway. Poly(isobutyl vinyl ether)s with Mn up to 8600 g mol−1 and relatively broad molecular weight distribution (Mw/Mn = 2.5–3.5) in high yield (>85%) were synthesized in aqueous dispersion. In direct emulsion, using BRIJ®98 (7 wt% to monomer) as a surfactant, polymers of low molecular weight (Mn ≤ 2000 g mol−1) and relatively narrow molecular weight distribution (Mw/Mn = 2.0–2.5) were obtained in moderate yields (50–60%), whereas, in inverse emulsion (water–n-hexane as a reaction medium), higher yields (85–96%) and higher molecular weights (Mn = 4500–5500 g mol−1) were reached. Chain-end analyses by means of 1H NMR spectroscopy revealed that most of the chains contain acetal end groups (typically ≥80%), while aldehyde (12–16%) and alkenal (0.5–3.5%) end groups were found in minor proportions.
Quantificação da degradação física do solo por meio da curva de resistência do solo à penetração

Soil resistance to penetration (PR) frequently reduces plant root growth. PR increases with soil bulk density (Bd) and decreases with soil moisture (θ), and the mathematical description of the relationships of PR with Bd and θ determines the soil penetration resistance curve (SRC). The objective of this study was to quantify the SRC of an Oxisol under different land use practices and to use it to describe soil physical degradation. Four areas were selected: (a) native forest; (b) pasture cultivated with Brachiaria humidicola for over 20 years; (c) area cultivated with citrus plants for 10 years; and (d) soil under annual crops for 15 years. In each treatment, 48 undisturbed soil samples were collected in the 0-0.10 m layer. Matric potential (Ψ) values from -10 to -15,000 hPa were applied to sets of 16 samples (4 per treatment) to simulate soil drying. The variables PR, Bd and θ of these samples were determined. A non-linear equation was fit to the experimental data to describe SRC (PR = a Bdb θc), in which a, b and c are coefficients of the fitted model. The fitted model explained more than 83 % of the PR variability in all treatments. In compacted soils a higher soil water content is necessary to maintain PR at adequated levels for plant growth (RP < 2.0 MPa). The PR values in soils under annual crops and citrus orchard were excessively high at θ values close to the field capacity (Ψ = -100 hPa), indicating greater soil physical degradation.
Experimental investigation of a circulating fluidized‐bed reactor to capture CO2 with CaO

Calcium looping processes for capturing CO2 from large emissions sources are based on the use of CaO particles as sorbent in circulating fluidized-bed (CFB) reactors. A continuous flow of CaO from an oxyfired calciner is fed into the carbonator and a certain inventory of active CaO is expected to capture the CO2 in the flue gas. The circulation rate and the inventory of CaO determine the CO2 capture efficiency. Other parameters such as the average carrying capacity of the CaO circulating particles, the temperature, and the gas velocity must be taken into account. To investigate the effect of these variables on CO2 capture efficiency, we used a 6.5 m height CFB carbonator connected to a twin CFB calciner. Many stationary operating states were achieved using different operating conditions. The trends of CO2 capture efficiency measured are compared with those from a simple reactor model. This information may contribute to the future scaling up of the technology. © 2010 American Institute of Chemical Engineers AIChE J, 57: 000–000, 2011
Structural Basis for Imipenem Inhibition of Class C β-Lactamases

ABSTRACT To determine how imipenem inhibits the class C β-lactamase AmpC, the X-ray crystal structure of the acyl-enzyme complex was determined to a resolution of 1.80 Å. In the complex, the lactam carbonyl oxygen of imipenem has flipped by approximately 180° compared to its expected position; the electrophilic acyl center is thus displaced from the point of hydrolytic attack. This conformation resembles that of imipenem bound to the class A enzyme TEM-1 but is different from that of moxalactam bound to AmpC.