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This paper focused on the studying of adsorption properties of Fe3O4-waste paper activated carbon composites for the removal of methylene blue dyes from water. The various parameters were carried out for the adsorption test of the composites, namely; contact time, adsorbent dose, initial MB concentration, pH solution, and temperature. The adsorption of isotherm, thermodynamics and kinetic was used to determine the characteristics of methylene blue adsorption onto the prepared adsorbent. The result indicates that the optimum adsorption capacity has occurred at pH = 6 in water solution. The adsorption capacity increase as the temperature increase until at 315K (45oC). The Langmuir isotherm is more appropriate to be applied as the adsorption model with the maximum adsorption capacity (qm) value of 101 and 93 mg/g for KA HCl-Fe3O4 and KA-Fe3O4 composites, respectively. The value of adsorption thermodynamic parameters was positive for ΔH, negative for ΔGo and positive for ΔSo, meaning the process adsorptions were endothermic, feasibility and spontaneity and randomness, respectively. The pseudo-second-order model was appropriate to predict the kinetic models for methylene blue adsorption onto the composites. The obtained adsorbent composites possess high adsorption efficiency and rapid magnetic separation. They were a promising for practical wastewater treatment for dyes removal from water.

Power transformer is one of the key equipment of the power grid, and its operation reliability directly affects the safe and efficient operation of the power grid. The main cause of transformer accidents is insulation failure. Therefore, aging characteristics and mechanism of oil-filled transformer oil-paper insulation has important academic value as well as application significance. Based on the quantum chemical simulation, this paper systematically studies the physical parameters of the transformer insulating paper molecules and their dissociation process. The results showed that as for the cellulose molecule with a degree of polymerization of 10, the energy gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital was 4.2038 eV. As for its repeating unit cellobiose, the 1,4-β-glycoside bond would be broken firstly, whose equilibrium bond length was 1.41813 A. Moreover, the bond energy was 54.18 kcal/mol, and the energy of the corresponding equilibrium configuration was -1298.2662 Hartree. Subsequently, the cellulose would generate a large amount of D-monoglucose monomer and some free radicals. The results in this paper contributed to establishing the model and the mechanism of oil-paper insulation aging process, and further identifying the aging degree of transformer and improving the reliability of transformer operation.

In this paper, two studies are presented whose main objective is to go further on the comprehension of thermally upgraded paper ageing. The first one is about the accelerated ageing of standard (STD) and thermally upgraded (TU) Kraft paper in mineral oil. After plotting the viscometric degree of polymerization (DPv) according to the kinetic model proposed by Calvini in 2005 [1], the model is validated for STD paper but not for T U paper. A modification of this model for T U paper is suggested to improve the correlation with experimental data. In the second part, a study is presented on the investigation of the effect of a nitrogen-based additive (DICY) concentration on the paper ageing in oil. The DPv results confirm the protective effect of the DICY on the cellulose chains and show that this effect depends on the nitrogen content, but not linearly. The pH of aqueous extracts and surface FTIR analysis brought new support for a hypothesis regarding the functioning mechanisms of the DICY that are reported in the literature.

Hypotheses (1) The equilibrium size and characteristics of a radially wicked fluid on porous material such as paper is expected to be dependent on the fluid properties and therefore could serve as a diagnostic tool. (2) The change in wicked stain size between biological fluids is dependent on a change in solid-liquid surface interfacial energy due to protein adsorption. Experiments Sessile droplets of increasing volume of blood, its components, and model fluids were deposited onto paper and the equilibrium stain size after coming to a halt was recorded. The contact angle of fluid droplets on model cellulose surfaces was measured to quantify the effect that blood protein adsorption at the solid-liquid interface has on radially wicked equilibrium size. Finally the significance of droplet evaporation for the time scale of interest was analysed. Findings The final stain area of all fluids tested on paper scales remarkably linearly with droplet volume. Different fluids were compared and the gradient of this linear relation was measured. Model fluids varying in surface tension and viscosity all behave similarly and exhibit a constant gradient. Blood and its components produce smaller stains, demonstrated by lower gradients. The gradient is a function of protein concentration, thus the mechanism of this phenomenon was identified as protein adsorption at the cellulose-liquid interface. The slope of the area/volume relationship for droplets is an important quantitative mechanistic variable.

A recent commentary by Santhosh and Ravindran on our paper (Int. J. Hydrogen Energy 2014, 39:10606) demonstrated that the interaction between H2 and MXene (Sc2C and Ti2C) phases are not Kubas-type and should be of weak physisorption, and thus made a conclusion that 2D Sc2C and Ti2C are not suitable for practical hydrogen storage applications. In this responses, we recalculated hydrogen adsorption on 2D Sc2C and Ti2C by using different exchange-correlation functionals. And based on the calculated results, bare MXenes (especially the Ti2C) are suitable as hydrogen storage materials at temperatures of several tens degrees lower than room temperature. And the hydrogen adsorptions on the MXenes terminated with oxygen group were also investigated. Among the Ti2C, Sc2C and their oxygen-functional counterparts, the binding energy of H2 on Sc2CO2 surface is the closest to the ideal range of 0.16–0.42 eV/H2 at ambient conditions, and thus the Sc2C with oxygen group is expected to be more suitable as hydrogen storage materials.

The purpose of this study is to determine the properties of the solvents responsible of the chromatographic phenomenon. A simple and homogeneous system of ascending chromatography on paper is described, allowing varying only one of the factors constituting it. This method made it possible to determine constants by means of a simple equation. The validity of the method is deduced from the good agreement between its mathematical expression and the experimental values obtained.

Errors are noted in the construction of the binary phase diagram in the paper “Physical characterization of Bis(2,2-dinitropropyl) acetal and Bis(2,2-dinitropropyl) formal” by Alexander Edgar, Just...

International audience; The fabrication of a fully bio-sourced adsorbent of Cd(II) by covalent immobilization of quinine on cellulose paper is described. The double bond of commercially available quinine was converted to a terminal alkyne function which was reacted with cellulose paper, chemically modified with azide functions, through a 1,3-dipolar cycloaddition, leading to Cell-Quin. The adsorption efficiency of Cell-Quin was investigated to determine the optimal pH, contact time and dose of adsorbent, ultimately leading to high levels of removal. The mechanism of adsorption of Cell-Quin was deeply rationalized through kinetic experiments and isotherm modeling. We also showed that Cell-Quin could adsorb other heavy metals such as Cu(II), Pb(II), Ni(II) and Zn (II).

The pyrolysis of cellobiose molecular model is simulated by using the molecular dynamics method based on reactive force field (ReaxFF). Studying the generation path of ethanol at the atomic level through a series of ReaxFF-MD simulations. Owing to the molecular systems have hydrogen bonding, fbMC is mixed into ReaxFF to save a lot of sampling waste. In order to ensure the reliability of simulation, the models composed of 40 cellobioses were respectively established for repeated simulation in the range of 500K-3000K. Simulation results show that insulating paper produced ethanol at high temperatures, and the intermediate product of vinyl alcohol is the key to the pyrolysis process. The simulation results are basically consistent with others' previous experiment results, which can provide an effective reference for the use of ethanol as an indicator to evaluate the aging condition of transformers.

Drying experiments of two paper mill sludge were carried using hot air with a temperature range of 50?C - 80?C and an air velocity of 0.96 m/son a laboratory convective dryer. The drying characteristics were discussed and the drying kinetic equation was solved. The dependence of the reaction rate constant on the drying temperature was given by Arrhenius equation, and the activation energies for moisture diffusion in paper mill sludge sample A and B were found to be 21.53 kJ/mol and 15.38 kJ/mol, respectively.

The anomalous heat effect reported in the paper, “Excess heat evolution from nanocomposite samples under exposure to hydrogen isotope gases” by Kitamura et al. published in the Int. J. Hydrogen Energy 43, pp. 16,187–16,200 (2018), is investigated in the science of the cold fusion phenomenon (CFP) established in these 30 years. It is concluded that the effect is a normal event in the CFP consistent with many events observed in materials with various components and compositions composed of host elements and hydrogen isotopes.

Co-pyrolyzing mixed wastes of the different physicochemical kinds is often a challenge. This study reports the co-pyrolysis of homogeneous polypropylene plastic and paper wastes, highlighting their characteristics, synergetic effects, and kinetic and thermodynamic parameters using robust thermal gravimetric analysis technique. Results show that 20% paper in the blend improved the bulky density, fuel ratio from 0.09 to 0.13, maximum degradation temperature from 369.55 to 447.88 °C and thermal stability from 381.60 to 393.82 °C. The average activation energies of the blend from Flynn-Wall-Ozawa, Friedman and Coats-Redfern were 148.73 ± 7.87, 133.98 ± 11.59 and 143.74 ± 13.83 kJ/mol, respectively, lower than at least one of the homogenous wastes. All the enthalpy and Gibbs free energy values were positive, thus, endothermic non-spontaneous pyrolysis. In addition, average enthalpies for the mixed sample were lower than homogeneous polypropylene (from 159.57 ± 11.86, 153.74 ± 16.07 and 181.27 ± 28.90 to 143.60 ± 24.42, 128.86 ± 34.61 and 138.61 ± 41.32 kJ/mol, respectively) in all models, respectively. The entropy values for all samples were negative. They decreased with increasing conversion rates for mixed waste samples, indicating ease to reach thermodynamic equilibrium during pyrolysis. There is an insignificant difference between the experimental and the calculated TGA/DTG curves, signifying meagre synergetic effects. In addition, the 3D surface response for the conversion rate against temperature and heating rate showed closeness in results between the homogeneous and mixed waste. The results of this study are vital in handling municipal solid waste without any need for isolation during the conversion process to valuable products.

Background and Aim: The coronavirus disease 2019 (COVID-19) vaccine helps to develop immunity to SARS-CoV-2, the virus that causes COVID-19, in most cases preventing the disease. Although various brands of vaccines work in different modes, all COVID-19 vaccines prompt an immune reaction to make the body remembers how to protect from the virus in the future. The present study aims to evaluate the safety and the immune response for mixing of Sputnik V and AstraZeneca COVID-19 vaccines on mice. Materials and Methods: Our experimental study was performed on mice weighing on average of 20 g, selected by random allocation. The mice were divided into four groups of 12. Group one received a single dose of 0.5 ml Sputnik V COVID-19 vaccine, group two received two doses of 0.5 ml AstraZeneca COVID-19 vaccine, group three received two doses of 0.5 ml Sputnik V together with 0.5 ml AstraZeneca COVID-19 vaccine and group four received two doses of 0.5 ml of 0.9 % NaCl. Results: Our study shows that mixing of Sputnik V and AstraZeneca COVID-19 vaccines is safe and induces good immunity for mice. Conclusion: Mixing of Sputnik V and AstraZeneca COVID-19 vaccines creates no problems and provides good immunity to mice and may be an interesting technique to help to overcome shortcomings of one or the other vaccine. Further toxicity studies are required to assess potential hazards for humans to evaluate the histopathological characteristics.

We propose a new method for determining the surface energy of paper and its components using the contact angle technique. Calendered sheets and model liquids were used in this study. A rapid evolution of the probe/handsheet contact angle with time was observed for all tested conditions. A suitable method for choosing the contact angle and a new model to determine the surface energy and its components is proposed. The total surface energy of paper hansheets (47.2–50.4 mN m−1) and its components (dispersive γd ~ 19–20, polar γp ~ 4–5 and hydrogen bond γh ~ 25–32) are in good agreement with literature data.

My comments concern the severe errors in the crystallographic part of the commented paper. The correct formula is proposed to be Bi1-xGdxFeO3 instead of BiFe0.95Gd0.05O3. Thus, the actual composition of the studied crystal is not known. Furthermore, it is evident that the sample contains at least three different phases. The subsequent studies do not present the properties of the title compound.

Cellulosic insulation paper is usually used in oil-immersed transformer insulation systems. In this study, the molecular dynamics method based on reaction force field (ReaxFF) was used to simulate the pyrolysis process of a cellobiose molecular model. Through a series of ReaxFF- Molecular Dynamics (MD) simulations, the generation path of ethanol at the atomic level was studied. Because the molecular system has hydrogen bonding, force-bias Monte Carlo (fbMC) is mixed into ReaxFF to reduce the cost of calculation by reducing the sampled data. In order to ensure the reliability of the simulation, a model composed of 20 cellobioses and a model composed of 40 cellobioses were respectively established for repeated simulation in the range of 500–3000 K. The results show that insulating paper produced ethanol at extreme thermal fault, and the intermediate product of vinyl alcohol is the key to the aging process. It is also basically consistent with others’ previous experiment results. So it can provide an effective reference for the use of ethanol as an indicator to evaluate the aging condition of transformers.

To go further in our assessment of methanol for the monitoring of the cellulosic insulation condition in electrical transformers, two of the paper/oil systems [one comprising a standard wood Kraft paper and the other, a thermally-upgraded Kraft paper (TU paper)] discussed in Parts 1 and 2 (Gilbert et al. in Cellulose 16:327–338. doi:10.1007/s10570-008-9261-1, 2009; Cellulose 17:253–269. doi:10.1007/s10570-009-9365-2, 2010) were reinvestigated under accelerated ageing conditions (T between 130 and 210 °C). The experimental data were tracked by testing two mathematical models, one that takes into account the inhomogeneous nature of the polymer by decreasing with time a pseudo-zero rate constant by a first-order process and the other, by simultaneously operating a separate first-order law for the three main categories of 1,4-β-glycosidic bonds in the polymer structure. These additional results provide evidence that the degradation proceeds via a random opening of these bonds in both the amorphous and crystalline regions, with the influence of a pyrolysis-like mechanism even at relatively low temperatures. Very good dependence with the temperature (lnk vs 1/T) is noted for the rate constants of the production of chain-end groups and the formation of methanol, confirming the importance of carrying out the ageing tests beyond the LODP of the specimens (leveling-off value of the degree of polymerization). The grouping of some of these data with those published in Part 2 for an identical system reveals that the degradation is governed by a single reaction pattern over 70–210 °C. The Arrhenius law applied to this data grouping shows an activation energy of 95 ± 4 kJ mol−1 with a frequency factor (lnAa) of 22 ± 1 for the depolymerization, while for the formation of CH3OH, the respective values are 122 ± 6 kJ mol−1 and 33 ± 2. Finally, the kinetic parameters obtained under accelerated ageing conditions over 150–210 °C show that the stabilizing substances of the TU-Kraft paper modify the bond opening mechanism by blocking the effect of the acid and water generated by the oil decomposition. When they are present in the fibrous structure, the activation energy of the reaction goes up to 148 ± 14 kJ mol−1 with a frequency factor of 33 ± 4 for the depolymerization and 133 ± 11 kJ mol−1 with a frequency factor of 33 ± 3 for the formation of CH3OH.

The migration model of contaminants from inks on paper packaging to food is developed based on the penetration of ink in paper and Fick's diffusion. The printed paper is divided as ink layer and paper layer. The mass transfer coefficient hm and partition coefficient KF,P in the interface between paper and food are considered in the model. The model equation is solved, and the migration expression is obtained by using the method of separation of variables. The fitting method is used between the model and the migration experimental data to obtain the diffusion coefficients and mass transfer coefficients for dibutyl phthalate (DBP) and acetyl tributyl citrate (ATBC). It is found that there exist linear relationships between ln(DP) and 1/T, and also between ln(hm) and 1/T for DBP and ATBC. The migrations of DBP in the paper sample 2402 at different temperatures and of ATBC in the paper sample 2401 at 50°C are predicted by using the model, and a good agreement is obtained between the model predictions and the migration experimental data. Copyright © 2014 John Wiley & Sons, Ltd.

It is shown that the composition of the investigated alloy is nearly identical to the commercially available alloy MP35N (35Co-35Ni-20Cr-10Mo, wt%). However, the thermomechanical treatment of the experimental alloy is quite different from that used for the commercial one which consists of using cold work followed by annealing at temperatures below the recrystallization temperature. Here, depending on the amouunt of cold work, a tremendous hardening effect occurs, due to Suzuki hardening which allows to tune the mechanical properties in a range much larger than obtainable by the strategy used by the High Entropy Community by creating hierarchical microstructures.

This article details a correlation study on early devolatilization behaviors (drying & volatile emission at 25–240 °C) and the change in mechanical properties (expressed by viscoelasticity) of four types of waste papers. The early stage of devolatilization was investigated using the TG-FTIR and mechanical properties using the dynamic mechanical analysis (DMA) method. The results show that the elastic and viscous mechanical properties showed obvious correlations with free and bound water evaporation and volatile emission. The storage modulus ( E ′ ) and loss modulus ( E ″ ) of the papers decreased as temperature increased and at the two important temperatures, namely 100 °C, the start of bound water evaporation, and 150 °C, the start of devolatilization in TG & DTG curves, E ′ showed extrema. Especially the relative storage modulus ( E ′ r ) exhibited a sudden decrease at around 150 °C, where the activation energy of thermochemical conversion jumps from low values to high values, indicating the start of devolatilization. CO2 is the major compound of the volatiles and it is well correlated with E ′ r in exponential function model and can be used as an index for predicting the E ′ r of the waste papers in their early devolatilization stage; while during the drying stage, mass loss ratio can be used to predict E ′ r of the waste papers.

Microcrystalline cellulose (MCC) powder was isolated from three grades of waste paper: book, Groundwood/Newsprint and paperboard, through the processes of pulping and hydrolysis. Pulping treatment on these grades of waste paper was done using varying concentrations of caustic soda. Effects of the concentration of the pulping medium on the thermal and kinetic properties were investigated. Also determined were the effects of this on the physico-chemical properties. The chemical structure was characterized using an infrared spectroscopy (FTIR). Results showed these properties to be affected by the concentration of the pulping medium.

Errors were discovered regarding the published equation coefficients of Yao and co-workers (2017) for mathematically describing the solubility of 3,5-dimethylpyrazole in nine organic solvents using the NRTL model. Larger differences were found between our back-calculated data and those reported in the authors' published paper. The equation parameters were re-regressed based on the reported solubility data.

It was an honor to receive the Max Jakob Memorial Award for 2018. This invited paper is based on the award lecture and is written in an informal style expanding on the lecture and focusing on work in which I have been involved over the past 60 years. Early experimental and theoretical work was published only in conference proceedings when this was regarded an alternative to a journal and not, as seems to be the case nowadays, prior to journal publication or for incomplete work. I welcome this opportunity to clarify and make some of this earlier work more readily accessible. My comments on more recent work of others are also included.

This paper presents the methodology used and the results obtained in the determination of moisture diffusion coefficient of non-impregnated transformer insulating paper. In order to establish the diffusion coefficient, drying curves of paper samples were obtained by means of thermogravimetric experiments. The diffusion coefficient parameters were found by applying an optimization process based on genetic algorithms. The error function between measured and simulated curves was determined, and the parameters achieving the best correspondence between measured and estimated values were obtained. As a result, a new equation for the diffusion coefficient of non-impregnated insulating paper is proposed, depending on average moisture concentration, temperature and insulation thickness. The proposed coefficient was validated through experimental cases finding a good agreement between the experimental drying curves and those obtained by simulation using the diffusion coefficient. The proposed diffusion coefficient can be used for the determination of the time required to dry power transformers in factory.

Adsorption isotherms of 3 selected paper-based packaging materials, that is, vegetable parchment (VP) paper, Kraft paper, and solid-bleached-sulfate (SBS) paperboard, were determined at 3 different temperatures (25, 40, and 50 degrees C). The GAB isotherm model was found to fit adequately for describing experimental adsorption isotherm data for the paper samples. The monolayer moisture content of the paper samples decreased with increase in temperature, which is in the range of 0.0345 to 0.0246, 0.0301 to 0.0238, and 0.0318 to 0.0243 g water/g solid for the MG paper, the Kraft paper, and the SBS paperboard, respectively. The net isosteric heats of sorption (q(st)) for the paper samples decreased exponentially with increase in moisture content after reaching the maximum values of 18.51, 27.39, and 26.80 kJ/mol for the VP paper, the Kraft paper, and the SBS paperboard, respectively, at low-moisture content. The differential enthalpy and entropy of 3 paper samples showed compensation phenomenon with the isokinetic temperature of 399.7 K indicating that water vapor had been adsorbed onto the paper samples with the same mechanism. Depending on the paper material, tensile strength of paper samples was affected by moisture content.

The objective of this chapter is to make better known Jean-Marie Souriau works, more particularly his symplectic model of statistical physics, called “Lie groups thermodynamics”. This model was initially described in chapter IV “Statistical Mechanics” of his book “Structure of dynamical systems” published in 1969. We have translated in English some parts of three Souriau’s publications which provide more details about this geometric model of Thermodynamics. Entropy acquires a geometric foundation as a function parameterized by mean of moment map in dual Lie algebra, and in term of foliations. Souriau established the generalized Gibbs laws when the manifold has a symplectic form and a connected Lie group G operates on this manifold by symplectomorphisms. Souriau Entropy is invariant under the action of the group acting on the homogeneous symplectic manifold. As quoted by Souriau, these equations are universal and could be also of great interest in Mathematics.

This paper presents the study of the feasibility of incorporating lignocellulosic nanofibers (LCNF) to paper in order to maintain the relevant physical properties and increase the number of cycles that paper can be recycled in the technosphere in a more circular economy. For that purpose, the effect of mechanical refining in recycling processes was compared with that of the novel LCNF addition. In this sense, the behavior of a bleached kraft hardwood pulp when recycled was investigated, as well as the effects of each methodology. Since there are many issues to be considered when trying to replace a technology, the present paper analyses its feasibility from a technical and environmental point of view. Technically, LCNF present greater advantages against mechanical refining, such as higher mechanical properties and longer durability of the fibers. A preliminary life cycle assessment showed that the environmental impacts of both systems are very similar; however, changing the boundary conditions to some feasible future scenarios, led to demonstrate that the CNF technology may improve significantly those impacts We acknowledge the financial support of the Spanish and Economy and Competitiveness Ministry to the referenced projects: CTQ2012-3686-C02-01 and CTM2011-28506-C02-01

Hu et al. reported the hydrogen storage properties of Sc2C and Ti2C based MXene phases utilizing density functional theory (DFT) as implemented in the CASTEP code [1, 2]. Based on such calculations, the authors suggest that the MXenes should be a new family of potential hydrogen storage media. Their results claim a maximum hydrogen storage capacity of 9.0 wt% with an average binding energy of 0.164 eV/H2 in Sc2C MXene indicating Kubas-type interaction between H2 and the MXene. These investigations are of prime importance since they provide insight about further applications of MXenes for hydrogen storage. In these calculations they have used local density approximation (LDA) to estimate the adsorption energies. However, binding energies for H2 with the MXene phases mentioned above obtained from more accurate calculations based on Generalised Gradient Approximation (GGA) and calculation including dispersion correction (GGA + vdW) show very weak binding energy ( ∼ 0.064 e V / H 2 ) suggesting weak physical interactions between H2 and the MXene phases. Our accurate DFT calculations predict that these MXene phases are not suitable for hydrogen storage at realistic conditions. So we conclude that appropriate exchange-correlation functional should be used to extract hydrogen adsorption energies in nano-phases to describe their hydrogen storage properties reliably.

Efforts were made to determine the activation energy and the reaction order by adopting Kissinger and Flynn-Wall-Ozawa analysis methods. All the data were acquired from TGA thermograms for the mixed fuels with different temperature heating rates. It could be known that both the coal and the mixed fuels decomposed thermally at temperature ranges of . The temperature at the maximum reaction rate, Tp, could be determined by DTG method, which could be obtained by differentiation of TGA thermogram. Kissinger analysis showed the linear relationship with experimental data, showing the activation energy of kJ/mol. From Flynn-Wall-Ozawa analysis, it was shown that the activation energies and the reaction orders did not undergo any significant changes with both the conversions and the heating rates. It was considered from this facts that the combustion mechanism of the mixed fuels could not be affected by the extent of conversion and heating rate. In the present study, the activation energies showed different values according to the different analysis methods. The difference might be originated from the inconsistency of the mathematical data treatment method. In other words, while the activation energies obtained from the Kissinger method indicated the average values for overall reaction, that from Flynn-Wall-Ozawa method showed the average values for the each conversion around Tp.

The paper “Mechanism of Thermal Runaway as a Cause of Fleischmann-Pons Effect,” by N.E. Galushkin, N.N. Yazvinskaya, D.N. Galushkin, published in the Journal of Electroanalytical Chemistry, 870, pp. 114,237 – 114,246 (2020), ISSN 0022-728, does not contain enough data on the study of nuclear reactions in CF materials that accompany the Fleischmann-Pons effect. Therefore, it is necessary to add an overview of these studies based on the data written in the papers by Fleischmann et al. and data including the paper by Morrey et al. and others obtained in these about 30 years.

A dynamic model describing the behavior of a multi-cylinder drying section in paper production plants was developed based on the mass and heat balances around drying cylinders. The balance equations consist of sets of differential equations describing heat and mass transfer around the canvas, the web and the drying cylinders. Values of cylinder temperatures and moisture contents were estimated and compared with operation data. To obtain further information for energy consumption, the generation of entropy at each drying cylinder was investigated based on the model developed.

The objective of this work is to analyze and compare the natural and forced convective drying of handmade recycled paper. Drying of recycled cellulose pulp was carried out under laboratory environment conditions and in a convective dryer with forced air circulation and controlled conditions of air temperature and velocity. The tests were conducted following a two-factor central composed factorial design of experiments, with six runs at the central point. The drying results were analyzed and fitted to mathematical models of Fick, Henderson and Pabis (Fick’s modified equation), Page and He (considering the nonlinear Fick effect). The model of Page represented best the experimental data and the one of Henderson and Pabis resulted in an adequate fit for the paper drying kinetics. Sorption isotherms were determined for the dried paper and the models of GAB (Guggenheim-Anderson-de Boer) and GDW (Generalised D’Arcy and Watt) resulted in excellent fits of the experimental data. The water sorption mechanism was suggested by the analysis of the calculated parameters of the GDW model.

An anisotropic elasto-plastic constitutive model of paper material is presented. It is formulated in a spatial setting in which anisotropic properties are accounted for by use of structural variables. A multiplicative split of the deformation gradient is employed to introduce plasticity. A similar approach is used to model the plastic deformation of the substructure. The yield surface adopted is based on the Tsai–Wu failure criterion, used previously to model failure of paper material. A non-associated plasticity theory is employed to calibrate the model to experimental data. It turns out that a multi-axial loading situation is needed to calibrate the model and here a biaxial tension test is audited. The model was implemented into a finite element environment and the creasing process of a corrugated board panel is investigated.

Although the knowledge concerning dewatering and consolidation of a paper web in a press machine has increased tremendously over the past few decades, there is still a need to improve the actual understanding, especially if high-temperature conditions and compression rates are involved, as in the case of impulse drying. In an effort to further understand the transport phenomena involved in impulse drying (i.e., conductive and convective heat and mass transfer with phase change), a heat- and mass-transfer model was developed and the results from the simulation runs were compared with experimental data collected in a fast-response laboratory platen press. Insight into the structural changes that occur when paper is compressed in the paper machine were also gained by the modeling and simulation of its viscoelastoplastic behavior. To characterize the nonlinear rheologic behavior of the material, a cellular solids theory approach was used. This approach resulted in an unsteady-state problem and the resulting s...

A novel paper-based dot immune-graphene-gold filtration assay (DIGGFA) for the detection of breast cancer cells was developed based on the photo-thermal effect of graphene oxide (GO)-Au nanocomposite. Anti-EpCAM antibody which specific to the MCF-7 cell surface antigen, was immobilized on the nitrocellulose paper. The GO-Au-anti-EpCAM composite would interact with the MCF-7 cells captured on the nitrocellulose paper. After the test zone was irradiated by a laser, GO-Au nanocomposite could generate heat, temperature contrast was recorded and positive correlated with the cell number. Standard curve was prepared according to the temperature contrast and the cell number. Under optimal conditions, this method could detect a minimum of 600 MCF-7 cells with a near infrared laser and an infrared temperature gun within 15 min. This simple and rapid method could be applied to the clinical diagnosis in hospitals.

Theoretical and experimental study of the paper drying process are presented. A mathematical model developed for combined heat ad mass transfer analysis of paper drying is given for both impinging air jets and through air drying methods. In this model, it is simply assumed that during the drying period of the paper has porous media and on the drying surface the vapour pressure of the evaporating liquid remains at a quasi-saturated value corresponding to the temperature of the liquid. The calculated transient paper temperatures in both methods agree well with the experimental results.

Photodegradation of lignin is one of the major postprocessing problems in paper production, as this renders yellowing of the paper and reduced paper quality. In this study, we have explored the photochemical properties of substituted stilbene derivatives believed to be key chromophores in the photodegradation of lignin derived from cinnamyl alcohol. In particular, the present work focuses on the computation of UV/vis electronic absorption spectra for different methoxylated stilbenes and their proposed photodegradation products. All calculations were performed using the time-dependent formalism of density functional theory (TD-DFT) and the B3LYP hybrid functional. It is concluded that the methodology employed is capable of reproducing not only the overall spectra, but also subtle features owing to the effects of different substitution patterns. For the strongly absorbing first excited singlet state (HOMO --LUMO excitation) of the methoxylated stilbenes, the calculated transition energies are, albeit somewhat fortuitously, in excellent agreement with experimental data. The light-induced yellowing indirectly caused by the presence of stilbenes can be rationalized in terms of the absorption spectra of the resulting photodegraded o-quinones, for which distinct transitions in the 420-500 nm region of the visible spectrum lacking prior to degradation are observed.

The theoretical models recently used by Chandra [Computational Condensed Matter 27 (2021) e00556] for computing the Gruneisen parameter are not valid at extreme compression but are valid at small compressions. Values of critical pressure for the validity of the Chandra models are about 24 GPa for e -Fe and 3.5 GPa for NaCl. It is emphasized that the third order Gruneisen parameter assumed by Chandra to remain constant for materials under the effect of pressure is not consistent with the recent investigations. We have developed a method for determining the volume dependence of Gruneisen parameter by taking into account the pressure dependence of third order Gruneisen parameter. The results have been obtained for e -Fe and NaCl which differ appreciably at high pressures from those computed by Chandra taking a constant value of third order Gruneisen parameter.

A mathematical model for through drying of paper at constant pressure drop was developed. The model is based on physical properties; hence, basis weight, pressure drop, drying air temperature, pore size distribution, initial gas fraction, and tortuosity are important input parameters to the model. The model was solved for different combinations of the variables basis weight, drying air temperature, and pressure drop corresponding to industrial conditions and the results were compared with data from bench-scale experiments. The simulations show that the drying rate curve is very sensitive to the air flow rate and that correctly modeling the correlation between pressure drop and air flow rate is the most important factor for a successful model for through drying. The model was tuned by adjusting the parameters initial gas fraction and tortuosity in order to give the best possible fit to experimental data. For a given basis weight and pressure drop, different drying air temperatures resulted in relatively constant values of the fitted parameters. This means that the model can well predict the effects of changes in drying air temperature based on a tuning of the model performed at the same basis weight and pressure drop. However, for a given basis weight, an increase in pressure drop yielded fitted parameters that were somewhat different; i.e., a lower initial gas fraction and a higher tortuosity, a change that increases the resistance to air flow. This implies that the correlation between pressure drop and air flow rate in the model does not quite capture the nonlinear relationship shown by the experiments.

H2, CH4, CO and CO2 yields were measured during supercritical water gasification (SCWG) of primary paper waste sludge (PWS) at 450°C. Comparing these yields with calculated thermodynamic equilibrium values offer an improved understanding of conditions required to produce near-equilibrium yields. Experiments were conducted at different catalyst loads (0-1g/gPWS) and different reaction times (15-120min) in a batch reactor, using either K2CO3 or Ni/Al2O3-SiO2 as catalyst. K2CO3 up to 1g/gPWS increased the H2 yield significantly to 7.5mol/kgPWS. However, these yields and composition were far from equilibrium values, with carbon efficiency (CE) and energy recovery (ER) of only 29% and 20%, respectively. Addition of 0.5-1g/gPWS Ni/Al2O3-SiO2 resulted in high H2 and CH4 yields (6.8 and 14.8mol/kgPWS), CE of 84-90%, ER of 83% and a gas composition relatively close to the equilibrium values (at hold times of 60-120min).

About 30 years ago a very important paper on “Applications of graph theory to enzyme kinetics and protein folding kinetics: steady and non-steady state systems” was published

Combustion of spent vacuum residue hydrodesulfurization catalyst and incineration of paper sludge were carried out in thermo-gravimetric analyzer and an internally circulating fluidized-bed (ICFB) reactor. From the thermo-gravimetric analyzer-differential thermo-gravimetric curves, the pre-exponential factors and activation energies are determined at the divided temperature regions, and the thermo-gravimetric analysis patterns can be predicted by the kinetic equations. The effects of bed temperature, gas velocity in the draft tube and annulus, solid circulation rate, and waste feed rate on combustion efficiency of the wastes have been determined in an ICFB from the experiments and the model studies. The ICFB combustor exhibits uniform temperature distribution along the bed height with high combustion efficiency (>90%). The combustion efficiency increases with increasing reaction temperature, gas velocity in the annulus region, and solid circulation rate and decreases with increasing waste feed rate and gas velocity in the draft tube. The simulated data from the kinetic equation and the hydrodynamic models predict the experimental data reasonably well.

This study is motivated by the need to develop a validated capillary pressure-saturation relationship that can precisely describe the capillary transport characteristics of the fuel cell diffusion media (DM). A series of capillary pressure-saturation measurements were performed for SGL 24 series DMs tailored with various degrees of PTFE loadings (from 5% to 20% of wt.) over a wide range of operating conditions (i.e. at different temperatures and compressions). The benchmark data were then utilized to deduce an appropriate form of Leverett approach that can precisely determine the capillary pressure of the tested fuel cell DMs as a function of hydrophobic additive content, operating temperature, liquid saturation, compression pressure and uncompressed porosity of the DM.

As there are no published data on the heats of solution of papermakers' alum [composition approximately Al2(SO4)3 14H2O] and only one value for the heat of solution of Al2(SO4)3, 18H2O in water, heats of solution at room temperature have been measured in the concentration range up to saturation, and all heat effects were found to be exothermic. The heat of solution per gram of alum is appreciably constant if more than 30 g. water is added. Heats of dilution were also exothermic. The resulting thermal data on solution and dilution were combined to give relative partial specific enthalpies of alum and water at all stable concentrations at 25–30°. A few measurements were made of heats of solution at 65–70°. Thermal effects were again exothermic but of smaller magnitude. By hydrating the alum fully a material almost identical with the normal sulphate, Al2(SO4)3, 16–17H2O, was obtained and its heat of solution at high dilution measured, from which the heat of hydration was calculated. About 50% of the heat of solution of alum is heat of hydration. These data enable all the heats of solution and dilution of alum to be recalculated in terms of Al2(SO4)3, 16–17H2O.

The excess isentropic compressibilities of binary mixtures of 1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide with ethyl acetate or methanol and 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide with dimethyl sulfoxide or methanol were calculated based on thermodynamically rigorous ideal mixing rule. For the discussed mixtures, great differences between excess values of isentropic compressibilities and isentropic compressibility deviations from a simple mole fraction average of pure components isentropic compressibilities are observed. The usability and correctness of the Prigogine-Flory-Patterson (PFP) model for mixtures under test is discussed as well, because in constructing the PFP theory, hydrogen bonds and interactions of strong electrostatic nature are excluded [Fluid Phase Equilib. 233 (2005) 157].