Second order kinetics

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Uptake of Toxic Hexavelantchromium Element from Aqueous Solution by Annona Squamosa Carbon

Uptake of Toxic Hexavelantchromium Element from Aqueous Solution by Annona Squamosa Carbon

Annona Squamosa was used for the preparation of activated carbon for the removal of toxic elements like chromium (V1) from waste water. The effects of concentration of pH, temperature, adsorption capacity have been investigated. Adsorption capacity of Annona Squamosa activated carbon was showed highest value around pH=3. A direct proportionality between the percentages of Cr (V1) removal (86.11%) requested within 15 min from start of every experiment .The Adsorption kinetic data were tested using pseudo-first order, pseudo-second order, and Elovich and intra-particle diffusion models. Kinetics studies showed that the adsorption followed a pseudo second order reaction of Cr(V1) followed pseudo second order kinetics equations and fits the Langmuir, Freundlich , Tempkin and Elovich equation well Activated carbon developed from Annona Squmosa seed can be highly efficient option for Cr(V1) from wastewater showed better removal percentage of Cr (V1) 1 .
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Photodegradation of basic dyes using nanocomposite (Ag-zinc oxide-copper oxide) and kinetic studies

Photodegradation of basic dyes using nanocomposite (Ag-zinc oxide-copper oxide) and kinetic studies

To introduce the applicability of the zero-order, first-order and second-order kinetics models for photocatalytic dye degradation by the nanocomposite at different initial dye concentrations, linear plots of A 0 - A versus irradiation time (t) for zero-order model (Fig. 11), ln (A 0 /A) versus irradiation time (t) for first-order order model (Fig. 12) and 1/A against irradiation time (t) for second-order model (Fig. 13) are plotted. The values of k 0 , k 1 and k 2 , R 2 (correlation coefficient values) are shown in
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Remediation of Surface Water Contaminated with Domestic Purpose Kerosene Using Fenton’s Oxidation

Remediation of Surface Water Contaminated with Domestic Purpose Kerosene Using Fenton’s Oxidation

adjusted to 3.0. At the end of the chemical remediation, the Fenton’s oxidation was found to be rapid with the reaction being exothermic and followed second order kinetics. About 44.4% of the total petroleum hydrocarbon (TPH) as kerosene removal efficiency was achieved after 90 minutes. The reaction also followed a pseudo-first order kinetics with the rate constant of 3x10 2 mol -1 cm 3 min -1 .

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Activation Energy of Modified Peak Shape Equations

Activation Energy of Modified Peak Shape Equations

For the expressions as a function of the peak temperature parameters, the E values for low temperature peaks are higher than the values obtained from the Table 3. Activation energies of ZnO from modified peak shape equations for both first and second order kinetics, as a function of the peak temperature parameters τ, δ and ω, and standard deviation from values obtained by peak shape formulas.

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Adsorption of Selenium From Aqueous Solution by Rice Husk : Characterization , Isotherm and Kinetic Studies Reena Mishra , Amit Chattree, Shazia Siddiqui

Adsorption of Selenium From Aqueous Solution by Rice Husk : Characterization , Isotherm and Kinetic Studies Reena Mishra , Amit Chattree, Shazia Siddiqui

The present study explores the adsorption potential of rice husk to remove selenium from aqueous solution. The presence of -OH , -NH ,and -CO groups play major role in adsorption of selenium ions onto adsorbent . The surface morphology pretends to be porous in nature. The optimum equilibrium time and pH was 120 min and 4.0. The adsorption isotherm fitted best was Temkin. The monolayer adsorption capacity of rice husk was 0.810 mg/g. The adsorption data was best fitted by pseudo- second order kinetics with regression coefficient of 0.997 and liquid film diffusion model was rate controlling step. The positive value of ∆H and ∆S suggest that the process was endothermic and randomness at solid - solution interface.
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Removal of Steriod Hormones by Activated Carbon Adsorption—Kinetic and Thermodynamic Studies

Removal of Steriod Hormones by Activated Carbon Adsorption—Kinetic and Thermodynamic Studies

Batch adsorption experiment using the bottle point method was performed at temperatures ranging from 15˚C to 35˚C for adsorption Isotherm test, varying weights of the granular activated carbon (0.05 g - 0.8 g) were added to 200 ml of E2 and EE2 aqueous solutions in 250 ml plugged conical flasks. The experiments were conducted at pHs 4, 6, 7, 8 and 10. The aqueous mixtures were agi- tated at a constant rate of 250 rpm. The experiments were conducted for 180 mins initially and subsequently for 120 mins. Samples were withdrawn at fixed time inter- vals for chemical analysis. The experimental data ob- tained were analysed using various kinetic models: Leger- gren pseudo first-order kinetics, pseudo second order kinetics, intra-particle diffusion kinetic model and the Langmuir and Freundlich adsorption isotherm models. The thermodynamic parameters which include Gibb’s free energy, enthalpy and entropy were also investigated. 2.3. Analytical Procedures
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Adsorption Studies for Removal of Acid yellow 17 using Activated Rice Husk

Adsorption Studies for Removal of Acid yellow 17 using Activated Rice Husk

Figure- 9: Second order kinetics for the removal of Acid yellow 17 using activated rice husk Figure- 8: First order kinetics for the removal of Acid yellow 17 using activated rice husk..[r]

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Investigation of Methyl Orange Adsorption from Water Using Acid Activated Makoro Clay

Investigation of Methyl Orange Adsorption from Water Using Acid Activated Makoro Clay

Acid activated Makoro clay samples were successfully prepared by acid leaching, grinding and sonication. Kinetics data showed that adsorption follows the Pseudo second order better than the pseudo first order mechanism. This would indicate a third order reaction. However, such a mechanism is very rare hence it is suggested that adsorption takes place on two different environments just as was found with coal in earlier work [25] that is the clay particle external surface and the internal surface in the pores created by acid activation. Consequently two simultaneous second order processes, known to display pseudo second order kinetics as well, are in operation in this case. Adsorption capacity of the activated clay increases from 1x10 -6 moles/g at an initial concentration of 4x10 -5 M to 2x10 -6 moles/g at 12x10 -5 M. The adsorption enthalpy and entropy change
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Adsorption of Benzene in Batch System in Natural Clay and Sandy Soil

Adsorption of Benzene in Batch System in Natural Clay and Sandy Soil

The aim of this study was to explore the possibility of using clay and sandy soil for removing polycyclic aro- matic hydrocarbon (benzene) from aqueous solution. The Langmuir, Freundlich and Tempkin Isotherms were used to analyze the adsorption equilibrium. The sorption rates of adsorbent dosage and adsorbate concentration with time were tested using pseudo first and second order kinetics, respectively. The study hopes to develop a cheap, readily available adsorbent and a viable technology for the removal of recalcitrant PAHs pollutants from the environment. The purpose of this study is to determine the extent of the bioavailability of benzene in clay and sandy soils; this is because benzene poses a potential hazard by ingestion in humans and animals.
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FORMULATION AND DEVELOPMENT OF IN VITRO EVALUATION OF GASTRO RETENTIVE FLOATING TABLETS OF QUINAPRIL

FORMULATION AND DEVELOPMENT OF IN VITRO EVALUATION OF GASTRO RETENTIVE FLOATING TABLETS OF QUINAPRIL

The present investigation was to develop and evaluate floating drug delivery system of an angiotensin-converting enzyme (ACE) inhibitor class of medications (Quinapril). The floating tablets of Quinapril were prepared by using HPMC K4M, HPMC E15LV, Carbopol 940 polymers. The tablets were prepared by direct compression method. Dissolution measurements were carried out in a (USP) dissolution testing apparatus II. The compatibility study of was performed by FTIR for the prepared Quinapril floating tablets confirms that there is no interaction between the drug and polymers used. The release data were subjected to different models in order to evaluate their release kinetics and mechanisms. The drug release kinetics was observed by Non-fickian diffusion mechanism and was concluded that the formulation with HPMC E15 LV shows better sustained release effect. The developed floating tablets of Quinapril may be used to prolong drug release for at least 12h, thereby improving the bioavaibility and patient compliance.
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The perception of second-order motion

The perception of second-order motion

There has been a considerable amount of research into speed discrimination thresholds in first-order motion perception. The basic findings are that, in the fovea and over a range of velocities fro m 2 V to 64°s'*, SDTs range between 0.04 and 0.1 (all SDTs will henceforth be given as Weber fractions) and that SDTs plotted against base velocities follow a U- shaped relationship. This has been shown with random dot patterns (De Bruyn & Orban, 1988) and luminance bars (Orban, De Wolf & Maes, 1984; Orban, Calenbergh, De Bruyn & Maes, 1985) over a wide range of target velocities. With increasing eccentricity the lower end of the U-shaped function is shifted towards higher velocities and the velocity at which optimum SDTs occur is increased. However, the upper limit appears to remain constant (De Bruyn & Orban, 1988). A number of studies have looked at velocity discrimination in sine wave gratings (Thompson, 1983; McKee, Silverman & Nakayama, 1986; Smith, 1987; Panish, 1988; Smith & Edgar, 1991) and Panish (1988) additionally examined SDTs in Gaussian luminance bars. Although the velocity ranges employed in these studies are smaller than those used by Orban (see above), the basic findings in terms of levels of SDTs and relationship between SDTs and base velocity are reproduced.
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Second order logic is logic

Second order logic is logic

The first chapter of the Thesis is introductory and historical. It gives the historical motivation for the present project and presents its conceptual roots. As has been mentioned, the prevailing thought through much of this century has been that, insofar as it makes sense to draw a line between logic and mathematics at all, it ought to be drawn at first-order logic. That is, first-order logic and any weaker system is generally accepted as being logic. Any system which is stronger, is deemed to be mathematics. The historical account begins with Leibniz who had a vision of an universal language which would serve as an uniting basis for all science, and by means of a picture script, would make all scientific truths plain. These are dim, and imperfectly related beginnings to Frege's more modest, but better argued vision: that we can show that arithmetic is just a more sophisticated logic. Frege's project is placed in the context of nineteenth century mathematical analysis. The
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Kinetics Adsorption of Silver Ion by Blend Chitosan-Polyvinyl Alcohol Resin

Kinetics Adsorption of Silver Ion by Blend Chitosan-Polyvinyl Alcohol Resin

coefficients for the pseudo-second order are greater than pseudo-first order. The adsorption capacity obtain from calculate accords very well with the adsorption capacity from experiment. The non-linear plots of pseudo-second order show a good agreement between experimental and calculated (Fig. 1(b) and Fig. 2(a)). This suggests that the adsorption of silver ion onto blend chitosan-polyvinyl alcohol resin is a pseudo-second order.

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Evaluating Sequential Disinfection in a Water Treatment System Using a Non-biological Surrogate.

Evaluating Sequential Disinfection in a Water Treatment System Using a Non-biological Surrogate.

In addition to the inability of the 2-D model to capture the 3-D mixing conditions, the model is also based on only one inactivation rate kinetic, which was obtained from Driedger et al [6] and is based on one ozone CT (CT of 1.4 mg*min/L). However, in this flow-through system, each microorganism will spend a different amount of time within the ozone contactors, thus experiencing a range of CT values. Different CT values will lead to different inactivation rate constants for the secondary chlorine disinfectant. Therefore, if a microorganism spends more time in the ozone contactors it will be subject to more ozone exposure and will most likely degrade more quickly once exposed to chlorine. The opposite is true if the microorganism is initially exposed to less primary ozone. Thus, inactivation kinetics for the secondary disinfectant used in this model may not completely capture the sequential disinfection experienced in a flow-through system.
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Effect of Light on Stability of Anthocyanins in Ethanolic Extracts of Rubus fruticosus

Effect of Light on Stability of Anthocyanins in Ethanolic Extracts of Rubus fruticosus

The initial content of total monomeric anthocyanins of EWS was 106 mg ∙l −1 which was considered to calculate the spectral data to cyanidin-3-glucoside. The effect of light on the content of monomeric anthocyanins was plotted as a function of time (Figure 2). The order of reaction for the degradation of anthocyanin by action of light was calculated by graphical method [13]. Figure 2 shows various graphs for each of the reaction orders: order zero, Figure 2(a), first order, Figure 2(b) and second order, Figure 2(c). Figure 2(a) shows that mono- meric anthocyanins concentration decreased 76% in one week when the extract was irradiated with a light source of 3968.30 lux. The decrease in the concentration of monomeric anthocyanins, which give the red color to fruit drinks, is a loss of food quality [8]. The monomeric anthocyanins concentration decreased 29% (P = 0.05) in extract stored at darkness. These results showed that this storage method is efficient to preserve the quality of blackberry extract. Increasing the intensity of the light source causes the gradual loss of monomeric antho- cyanins (Figure 2(a)).
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3.0 Second Order Circuits

3.0 Second Order Circuits

natural frequency, which indicates the frequency at which the system will oscillate if there is no dampling. The natural frequency ω n has units of radians/second. ζ is the damping ratio, which indicates how much damping there is in the system. A damping ratio of zero indicates there is no damping at all. The damping ratio ζ is dimensionaless.

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Second Position Clitics and Monadic Second Order Transduction

Second Position Clitics and Monadic Second Order Transduction

The simultaneously phonological and syn- tactic grammar of second position clitics is an instance of the broader problem of ap- plying constraints across multiple levels of linguistic analysis. Syntax frameworks ex- tended with simple tree transductions can make efficient use of these necessary ad- ditional forms of structure. An analysis of Sahidic Coptic second position clitics in a context-free grammar extended by a monadic second-order transduction exem- plifies this approach.

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Adsorptive Removal Of MB Dye By Graphitic-C3N4 From Industrial Effluents

Adsorptive Removal Of MB Dye By Graphitic-C3N4 From Industrial Effluents

Abstract— Dyes in surface water are widely found due to extensive use of colorants in various industries such as textiles, printing and food plants. The contaminated effluents are the crucial reasons for water pollution. Due to their obstinate or non-biodegradable nature the omnipresence dyes pose a great threat to the aquatic animals, are very toxic to mammals and act as carcinogens. The practiced methods for removing the dyes from ground water such as electro-coagulation, reverse-osmosis and ultra-filtration are burdensome, high-cost and non-repeatative. Adsorption with nanomaterials such as activated carbon (AC), carbon nano-tubes (CNT), mesoporous material and graphene has been successfully carried for removal of dye by adsorption. In this paper we have used a 2D nano material g-carbon nitride (g-C3N4) as an adsorbent as it has no toxic effect. The synthesis of g-C3N4 was carried out by taking melamine as the source material. The prepared g-C3N4 was characterized by powered XRD, FTIR and Raman spectra. The adsorption study of Methylene Blue (MB) was studied by changing various parameters such as initial concentration and pH of the solution, adsorbent dose and agitation time. The adsorption isotherm of MB onto g-C3N4 fitted well to Langmuir model indicating homogeneous monolayer adsorption. The adsorption kinetics followed a pseudo-second order mechanism. The maximum uptake for MB was 99% at a pH value of 9,initial concentration 100 ppm and adsorbent dose of 0.02 g for a contact time of 2 h.
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Kinetics of ethylene polymerization over titanium-magnesium catalysts: The reasons for the observed second order of polymerization rate with respect to ethylene

Kinetics of ethylene polymerization over titanium-magnesium catalysts: The reasons for the observed second order of polymerization rate with respect to ethylene

Thus, the data obtained by analyzing the dependences between the degree of polymerization and ethylene concentration upon polymerization either with or without hydrogen using various catalysts show that the chain propagation reaction is first-order with respect to ethylene. In this case, the observed greater order of the polymerization rate with respect to ethylene is supposed to be due to the fact that the number of active sites depends on ethylene concentration. When analyzing the possible reasons for the effect of ethylene concentration on the number of active sites, one should take into account the following experimental data obtained in this study:
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Second order splitting for a class of fourth order equations

Second order splitting for a class of fourth order equations

which isn’t positive semi definite for any λ > 0. We will thus consider a situation where C does not induce a positive semi-definite bilinear form. Note that this work is not a direct generalisation of the results in [13,16], whilst we consider a weaker condition on C this is accommodated by a stronger condition on the operator which acts on w in the second equation, chosen to be the negative identity map in (1.3).

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