Search

This manuscript aimed to enhance the mechanical, thermal, and ignition properties of bagasse paper when coated with different coatings synthesized from hydroxyethyl cellulose, 1,3-di-p-toluidine-2,2,2,4,4,4-hexachlorocyclodiphosph(V)azane, Talc powder, NaHCO3, cellulose nanocrystal. The effect of these coatings on the mechanical properties was studied by measuring elongation, tensile strength, and burst strength. The stages of degradation and ash residue of the measuring specimens were determined using thermal gravimetric analysis (TGA), behind that, the ignition properties as the flame chamber (UL/94), and limiting oxygen index (LOI) was measured according to standards. These tests proved that 1,3-di-p-toluidine-2,2,2,4,4,4-hexachlorocyclodiphosph(V)azane has a direct effect on improving the mechanical characteristics and enhancing the ignition properties of the coated specimens compared to uncoated. In this study the physical, mechanical, thermal, and ignition properties of the bagasse paper sheets were enhanced by easy and low-cost method via synthesis of new coatings based on commercially available chemicals in a reasonable cost.

This paper aimed to modify the ignitability of the bagasse paper by using talc powder, 1,3-di-aniline-2,2,2,4,4,4-hexachlorocyclodiphosph(V)azane, and nanocellulose crystal. The formation of cellulose nanocrystals (CNCs) was detected using transmission electron microscopy (TEM), X-ray diffraction (XRD). Thermal analysis as thermal gravimetric analysis (TGA) of the specimens recorded the improvement of the highest % of ash residue at 750 °C compared to the untreated one. The shape of the flame spread was studied. The ignition properties were studied for the untreated and treated specimens by limiting oxygen index (LOI) and flame chamber (UL/94), which recorded enhancing compared to the untreated specimen. This improvement was recorded either by measuring the mechanical properties (tensile strength, burst strength, elongation, and elasticity) of the specimens. The current article showed that the treated specimen was recorded the highest values compared to the untreated one in all physical, mechanical, and ignition properties, so these treatment paper sheets may be used as fire-retardant packaging materials.

A novel material for the deacidification and protection of paper has been designed by using MgO filled halloysite nanotubes (Hal). The ability of MgO loaded nanotubes to control the acidic conditions was evaluated by pH measurements in aqueous solvent. Afterwards, paper was impregnated into hydroxypropyl cellulose dispersions containing the consolidating material. A simulation of strong acidic conditions allowed us to evaluate the deacidification effect of the composite material on the samples. In particular, the paper reaches a pH of 7.7 after 1 h exposition to HNO3 vapours when MgO-Hal nanoparticles are added to the impregnation mixture at a concentration of 10 wt% and it remains still neutral after 12 h. Dynamic mechanical analysis showed that the tensile strength of the consolidated paper is improved, since the stress at breaking increase of ca. 8% for the samples treated with MgO-Hal compared to the untreated paper. Due to the presence of halloysite loaded with the alkaline reservoir, the acidic degradation of cellulose is neutralized as suggested by the stored energy which is similar to the pristine paper without any chemical attack. Therefore, the mechanical performances of the paper are preserved during the aging together with its macroscopic aspect, as suggested by colorimetric analysis. The proposed consolidation protocol represents a further step for the self-healing and long-term protection of cellulose based artworks.

Discharged pulp and paper mill wastewater (PPMW) were collected near M/s K. R. pulp and papers Limited, Shahjahanpur, India. Chemical analysis of the wastewater showed high BOD (3653-4180 mg L-1) and COD (17890-19100 mg L-1) values from two different sampling sites. The levels of total phenol were in the range of 389-432 mg L-1, nitrogen (125-234 mg L-1), sulfate (1926-2098 mg L-1), chloride (3.12-5.43 mg L-1) and lignin (38950-39000 mg L-1) along with various heavy metals (Fe, 87-79; Zn, 34-22; Cu, 3.28-2.57; Cd, 1.90- 0.36; Ni, 6-5, and Pb, 41.23-36.54 mg L-1); these were above the permissible limit as recommended by the CPCB and the USEPA. The BOD/COD ratio was 20% concentration of PPMW, α-amylase production was inhibited and chromosomal segregation at metaphase and anaphase during cell division was disturbed which resulted in c-mitosis, sticky chromosomes, and laggard chromosomes. In addition, SEM of the root of A. cepa showed fissures and fractured tissues of the root cap, probably due to the inhibition of auxins that were responsible for root cap formation. The findings indicated A. cepa as a good test model for examining the DNA damage and cytotoxicity by PPMW; and the discharged effluent should be treated at the tertiary stage for environmental protection.

Among the largest producers of waste, the paper industry stands out due to its impact on human health and ecological balance. However, these residues may also contribute to a more environmental friendly brick industry, since the incorporation of fluxing agents may improve the firing process and the induced porosity reduces thermal conductivity of fired bricks. Therefore, this study aims to assess the feasibility of replacing clay with solid paper residue (PPR) from 2.5 to 17.5% in order to reduce resources depletion and improve brick performance. The original clay was characterized as a non-calcareous red clay with high contents of kaolinite. Several samples were made by extrusion and fired at 900 °C in accordance with industrial procedures. The addition of PPR led to increase shrinkage from 5 to 10% due to the effect of fluxing oxides which reduced pores volume and enlarged pores size. In addition, the impervious fraction was slightly reduced while the apparent porosity certainly increased (i.e. approx. 17%) due to the macroscopic pores developed by PPR combustion. This porosity produces lighter bricks (i.e. density decays from 1.76 to 1.39 g dm−3) with lower thermal conductivity (i.e. from 5.53 to 0.41 W m−1 K−1) but also reduces compressive strength (i.e. from 11 to 3 MPa) and increases water absorption (i.e. up to 24%). Nevertheless, toxicity is below the regulatory limits in all cases and fired bricks are easily adaptable to industrial procedures. It must be noticed that this work was supported by the Chilean National Commission on Research and Development (CONICYT) [grant number FONDECYT REGULAR 1180414]. Technical and human support provided by CICT of Universidad de Jaén (UJA, MINECO, Junta de Andalucía, FEDER) and by Centro de Manejo de Residuos y Energía (BIOREN) Universidad de la Frontera (Chile) are gratefully acknowledged.

Due to the scarcity of natural resources, the option for the recovery of industrial waste for new processes has increased over the last years. However, seeking natural raw materials, some industrials do not perform treatment or separation of some of its components from waste to be reused. This research focuses on the characterization and purification of waste from the industrial pulping of white paper shavings, obtaining kaolin and CaCl 2 . The waste was subjected to heat treatment at 400 °C to burn the cellulose. To separate the CaCO 3 of kaolin, a hydrochloric acid (HCl) solution was used to purify the materials, converting CaCO 3 into CaCl 2 and water in a chemical reaction. To find the best HCl ratios, tests were carried out at three different concentrations: 1.5, 1.8, 2.1 M. Residual water was evaporated to recover the CaCl 2 , and the resulting kaolin from pulp was oven-dried and turned into metakaolin. The analysis performed for the characterization of the materials were: X-ray Fluorescence (XRF) before and after treatment of the material; X-ray Diffraction (XRD); Differential Thermal Analysis (DTA) and Thermogravimetric Analysis (TGA). Scanning Electron Microscope (SEM) was used on the surface structure, morphology and shape studies.

The conventional package paper was coated with biodegradable montmorillonite/chitosan nanocomposite, in order to extend the application scope of paper. The effect of coating weight, montmorillonite dispersion rate, montmorillonite and dispersant content on the surface and penetration properties of montmorillonite/chitosan nanocomposite coated paper were being investigated. The surface properties of the coated paper were observed by using scanning electron microscope (SEM) and atomic force microscope (AFM). The water permeation and water vapor barrier properties were confirmed through penetration dynamics analyzer (PDA) and water vapor permeability tester (WVP), respectively. The results indicated that montmorillonite/chitosan nanocomposite had a poorer formation than pure chitosan, but it had better water vapor barrier properties. The paper coated with lower content of montmorillonite, or with higher dispersion speed and dispersant content, had better smoothness and elongation. Additionally, the coated paper had excellent barrier properties under the conditions of high montmorillonite and dispersant content, dispersion rate and coating weight.

Graphite materials are widely used as electrode materials for electrochemical energy storage. N-doping is an effective method for enhancing the electrochemical properties of graphite. A novel one-step N-doping method for complete and compact carbon paper was proposed for molten salt electrolysis in the LiCl-KCl-Li3N system. The results show that the degree of graphitization of carbon paper can be improved by the electrolysis of molten salts, especially at 2.0 V. Nitrogen gas was produced at the anode and nitrogen atoms can substitute carbon atoms of carbon paper at different sites to create nitrogen doping during the electrolysis process. The doping content of N in carbon paper is up to 13.0wt%. There were three groups of nitrogen atoms, i.e. quaternary N (N-Q), pyrrolic N (N-5), and pyridinic N (N-6) in N-doping carbon paper. N-doping carbon paper as an Al-ion battery cathode shows strong charge-recharge properties.

This paper introduces physical models of drill string whirling and torsional vibrations and analyses the physical models in V.I. Gulyayev's three papers on drill string whirling and torsional vibrations: “V.I. Gulyayev, L.V. Shevchuk, Drill string bit whirl simulation with the use of frictional and nonholonomic models, Journal of Vibration and Acoustics 138(1) (2016) 011021”, “V.I. Gulyayev, L.V. Shevchuk, Nonholonomic dynamics of drill string bit whirling in a deep bore-hole, J Multi-body Dynamics 227(3) (2013) 234–244” and “V.I. Gulyayev, SN Hudoliy, O.V. Glushakova, Simulation of torsion relaxation auto-oscillations of drill string bit with viscous and coulombic friction moment models, J Multi-body Dynamics 225 (2011) 139–152”. This work finds that the physical models described in these three papers are clearly incorrect. Keywords: Drill string, Vibration, Lateral, Torsion, Whirl

Recently, it was indicated that a feasible industrial alternative to valorize the sludge obtained from the treatment of waste water effluent of paper fabrication in Europe is its use as raw material in the production of clay bricks. The present technical note is an open report, probably first in Americas, on a Brazilian industrial-scaled solution for this kind of sludge. As a novelty, the sludge was added to a mixture of clays for improved technical properties of construction bricks. Both bricks, added with 10 wt% of sludge and conventional pure clay bricks for comparison, were simultaneously fired at a relatively low temperature of 750 °C according to the ceramic fabrication procedure. The technical characterization was performed by linear shrinkage, water absorption and mechanical compression tests as per Brazilian standards. The brick consolidated structure was analyzed by optical microscopy. Environmental impact was evaluated by solution test and atmospheric emission by monitoring the release of SO2, NOx, TOC, CO and particulate material, according to Brazilian standards. The results showed that, owing to its composition and firing temperature, the addition of paper sludge into clay bricks contributes to a substantial reduction in price associated with a saving of 3% of fuel similar to that reported for Spanish kilns, during the industrial firing stage. The paper sludge added clay bricks attended the technical and environmental standards.

The Wabigoon River (Ontario, Canada) was affected by dams starting in 1898 and was polluted with pulp and paper mill wastes starting in 1913 and mercury from a chlor-alkali plant from 1962 to 1975. A dated sediment core from a riverine lake was analysed to investigate resultant changes in the biogeochemistry of mercury as revealed by variations in mercury isotope ratios and sediment chemistry. A total mercury maximum formed by the mercury pollution coincided with minimums in the δ-values of the 198Hg/202Hg, 199Hg/202Hg, 200Hg/202Hg, and 201Hg/202Hg ratios, and the δ-values decreased in the order δ201Hg > δ200Hg > δ199Hg > δ198Hg. Thus, mass-dependent fractionation caused depletion in lighter isotopes, implying evaporation of Hg(0) and pollution of the atmosphere as well as the river-lake system. Concurrently, mass-independent fractionation caused 199Hg enrichment, possibly reflecting an independently documented upsurge in methylmercury production, and 201Hg depletion, suggesting removal of methylmercury with anomalously high 201Hg/199Hg ratios by aquatic organisms and accumulation of 201Hg-depleted inorganic Hg(II) in sediments. The δ201Hg/δ199Hg ratio rose abruptly when mercury pollution began, reflecting the resultant increase in methylmercury production, and remained high but gradually declined as the pollution abated, paralleling trends shown by methylmercury in aquatic organisms. The δ201Hg/δ199Hg ratio of pre-1962 background mercury increased ca. 1898 and ca. 1913–1929, suggesting accelerated methylmercury production due to stimulation of microbial activities by the damming of the river and the input of pulp and paper mill wastes, respectively. Other variations were linked to economic and technological factors that affected pulp and paper manufacture.

Hybrid material based on halloysite nanotubes (HNTs) and sodium perfluorooctanoate (NaPF8) was used as a consolidant for paper treatment. The consolidation efficiency was determined by thermogravimetry as well as by paper grammage determination. Morphological analysis of the treated paper was performed by means of scanning electron microscopy while the effect of modified HNTs on the thermal behaviour of the cellulose fibres was investigated by differential scanning calorimetry which determined the combustion enthalpy of the paper.Water contact angle measurements were performed to study the paper wettability. The physico-chemical properties investigated (mesoscopic structure, thermal stability and wettability) of the treated paper were correlated successfully with the consolidation loading and, consequently, to the affinity between the fluorinated modified HNTs and the fibrous cellulose structure. This study proposes a new green protocol for paper consolidation based on natural tubular nanoparticles with a flame retardant effect.

The large amounts of sewage sludge (11 million tonnes in Europe in 2005) produced in paper manufacturing plants require the introduction of recycling and/or alternative recovery solutions to minimize the amounts of generated waste, such as its use in soil remediation or in the cement industry. A feasible alternative to valorize that waste is the use of paper sludge as raw material in the production of structural ceramic or clay bricks. Previous studies tried to incorporate sewage sludge from different sources into ceramic matrices, unfortunately with little success in the final result for most types of sludge. However, those experiments carried out using as additive sludge from the paper industry succeeded in producing a material suitable for the red ceramic industry. In this paper, binary mixtures of clay and paper sludge under different formulations were produced and their physico-chemical properties were studied. Increasing the paper sludge content in the clay mixture provides the material with improved properties regarding its thermal and acoustic insulation, but in turn it decreases its mechanical strength. However, this fragility of the material is compensated by an increased ductility. Regarding metal leaching, the studied ceramics have no environmental restrictions as far as their use as building material is concerned, as the obtained results were virtually identical to those for the blank samples (100% clay). Results showed that the presence of dichloromethane (373.2 μg m − 3 ) and propanone (61.2 μg m − 3 ) in the samples with added sludge was relatively relevant with respect to concentrations in samples made of 100% clay. All monocyclic aromatics detected showed a concentration level far below their odor threshold. In general, thus, it can be concluded that volatile organic compound (VOC) emissions during firing of the new ceramic material do not involve any particular problem. Finally, the experience obtained after more than 10 years of industrial production of this new mixed ceramic product was also analyzed. This analysis allowed confirmation that clay brick production with incorporation of paper sludge waste is a feasible solution from a technical point of view. As a key outcome, this fact has helped the reduction in a large proportion the amount of sludge produced by the Spanish paper industry ending up in landfills.

Objective The effect of organic modified bentonite on rheological behavior of paper coating was studied to extend the use of bentonite in the paper industry. Background In the coating process, the paper coating was performed in various shear forces. Therefore, the rheological properties of the coating had profound effects on the quality of coated paper. In order to achieve the good rheology, paper coating required the addition of thickener or rheology modifiers. Organic bentonite was a kind of thixotropic ge1, which was extensively used in a number of applications as rheology modifier to modify the rheology and control the stability of systems. Method Na+-bentonite was modified with diallyl dimethylammonium chloride and dodecyl trimethylammonium chloride, respectively. The organic bentonite was characterized by XRD and TGA and the rheological properties of paper coating containing organic bentonite were measured by rheometer. Results The XRD spectra showed that the 001 reflection of bentonite was shifted to a lower 2θ after the modification. Moreover, the modification with DTAC had more pronounced effect than with DADMAC. The TGA curve showed that one dehydration stage in the range of 30–155 °C was observed. For organic bentonite, thermal degradation took place in two stages. The first step was obtained in the temperature range of 250–600 °C and the second step took place between 600 and 900 °C. The addition of modified organic bentonite resulted in the increases of yield stress and viscosity of coating, and they increased when the amount of organic bentonite was increased. The flow characteristics fitted well with the Herschel–Bulkley model, and the rheological properties of paper coatings exhibited typical pseudoplastic behavior. Conclusion (1) The organic modifying agents were successfully inserted into the interlayer space of bentonite, the bonded amount of DADMAC and DTAC was 0.107 g/1 g Bent-DADMAC and 0.124 g/1 g Bent-DTAC, respectively; (2) organic bentonites had the thickening and promoting rheological function for paper coating; and (3) the paper coating containing organic bentonite exhibits the pseudoplastic fluid.

We would like to make some comments on the paper by Hamidatou et al. (2019). Initially, these comments are motivated to reveal that, previous results on probabilistic seismic hazard analyses, some of them computed and published by our research group, are wrongly quoted in the paper by these authors. In our opinion, some other points are worthy of debate, mainly, but not only, the used seismic source zone model, the used logic-tree, and also the comparison of estimated values of peak ground horizontal acceleration (PGA) with previous results.

Boric acid is known to be difficult to immobilize because it has a pKa of 9.23, which means it is present in a molecular form in most aqueous environments and can be changed in the structure and nature with the change of the environmental conditions. Layered double hydroxides (LDHs) are potential sorbents for borate. However, the drawbacks of using LDHs for borate removal are that they are affected by the presence of other anions and are difficult to separate from water. In the present work, novel composites of Mg–Al type of LDH, synthesized onto filter papers and then intercalated with gluconate (F-LDH-G) were prepared. LDH with interlayer of carbonate form was first immobilized onto the surface of filter paper (F-LDH-CO3) by in situ hydrothermal crystallization, and then ion-exchanged sequentially with chloride (F-LDH-Cl) followed by gluconate. The influence of the molar ratio of gluconate/LDH and reaction time on F-LDH-G synthesis was explored. Products were characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy and nuclear magnetic resonance as well as measurements of borate sorption. The optimal molar ratio of gluconate/LDH and reaction time for preparing F-LDH-G from F-LDH-Cl were 40 and 24 h (F-LDH-G-40–24 h), respectively. F-LDH-G-40–24 h had higher sorption density and greater stability than both the original filter paper and the filter papers containing other LDHs, even in the presence of other anions. 11B NMR and XRD results indicate that the principal mechanism for borate immobilization on F-LDH-G-40–24 h is complexation of gluconate with borate in both bischelate and monodentate forms. The novel composite is boron-specific and facilitates solid/liquid separation.

The present study was conducted to modify kaolin clay by coating cationic starches, maize and tapioca, aimed at effective incorporation into recycled pulp fibers. The modification process was examined by using zeta potential, filler size, filler retention, and scanning electron micrograph (SEM) observations. In addition, paper sheets (65 ± 5 g/m2 basis weight) filled with unmodified kaolin or kaolin–starch filler followed by an internal sizing were fabricated and analyzed. Based on the results of zeta potential, the charge reversal of kaolin–starch particles substantiated the coating of kaolin fillers by cationic starches. Additionally, the kaolin–starch filler revealed a higher tendency to form clusters 3.5–7.5 times larger than the unmodified kaolin filler. Consistently, SEM images showed well–distributed kaolin–starch fillers, aggregated together and jointed to the fibers. Consequently, the paper filled with kaolin–starch fillers exhibited higher brightness and mechanical strengths indices compared to the unfilled papers, as well as the papers filled with unmodified kaolin. Interestingly, the results of water resistance and dynamic contact angle (DCA) indicated stable hydrophobic performance of kaolin–starch filled papers.

This study introduces a contribution of using the El Minia carbonate filler pigment for paper making. El Minia limestone samples were grind to very fine powder ranging from 2 to 10 μm, for utilization in paper filler/coating industry, with using testing techniques; X-ray fluorescence (XRF), X-ray diffraction (XRD), Scanning electron microscopy (SEM). The limestone assessment includes more examinations to confirm the suitability of studied samples for alkaline paper manufacture such as, chemical analysis and physical properties, brightness, refractive index, oil & water absorption, moisture content, water soluble, surface area and soundness tests as per paper industry standards. Keywords: Calcium carbonate, Paper filler, El Minia, Inorganic pigment

Studies on the influence of paper mill wastewater, which affects photosynthesis, on reed chlorophyll and biomass can provide a theoretical basis for the ecological restoration of wetland plants. The influence of different concentrations of wastewater (chemical oxygen demands (COD) of 300, 175 and 50 mg•L−1) and different irrigation times (germination, blade-expansion, rapid-growth, heading and maturity stages) on the contents of chlorophyll a, chlorophyll b, total chlorophyll and chlorophyll a/b in reeds were tested in experimental pools that simulated the wetland ecosystem of the Liaoning Shuangtai estuary. The contents of chlorophyll a, chlorophyll b, total chlorophyll and chlorophyll a/b all increased significantly with increasing concentrations of wastewater, and their contents all differed significantly from each other. The contents of chlorophyll a, chlorophyll b and total chlorophyll were maximal when irrigated at the beginning of all growth stages with COD of 300 mg•L−1(C1O) at 2.253, 0.458 and 2.711 mg•g−1 fresh weight (FW), respectively, with irrigation at the rapid-growth stage and were minimal in the control plants at 0.142, 0.068 and 0.210 mg•g−1 FW, respectively, with irrigation at maturity. Chlorophyll a/b was maximal at C1O at 5.753 with irrigation at germination stage and was minimal in the control plants at 2.113 with irrigation at maturity. Reed biomass was maximal at C1O at 3.26 kg, which was 2.76 times higher than the control. Reed biomass was positively correlated with the content of chlorophyll and with COD in the wastewater. Paper mill wastewater generally increased the content of chlorophyll and the net photosynthesis rate and enhanced the growth of reeds.

This paper examines the water absorption-desorption behavior of geosynthetics clay liners (GCLs) using vapor equilibrium method (VEM) as well as the water retention behavior of partially saturated GCLs using the filter paper (FP) method. An overburden pressure equivalent to that of landfill cover soil was applied onto the GCLs to understand the stress- and time-dependent water absorption and desorption behavior of GCLs. The influence of calibration curves for obtaining total and matric suction from FP method on water retention behavior of GCLs was examined. The experimentally obtained discrete suction-gravimetric water content data were fitted with recently developed water retention curve (WRC) models to obtain WRC key parameters which may be used for modeling purposes. This study provides a systematic evaluation of the method of testing, the effect of calibration curves and WRC models on the WRC key parameters. Results show that the relative humidity (RH) and the overburden pressure have a significant influence on the water absorption and desorption behavior of GCLs. In addition, the equilibration time of both absorption and desorption behavior depends on the RH. The WRC (matric or total suction) of GCLs at higher suction obtained using few calibration curves from the FP method is in agreement with VEM. Results also conclude that data obtained using various calibration curves have a significant influence on the WRC key parameters.

I thank the discussors for their critique of the above paper. In geology there are rarely any absolute models but working hypotheses, which will be modified with new data. The paper under discussion, Charrach (Carbonates Evaporites 33:727–766, 2018a), presents a very new large data set, which is multi-disciplinary and integrated the most recent research. The critique by Moller et al. (Carbonates Evaporites https://doi.org/10.1007/s13146-019-00486-3, 2019) and their paper of 2018 (Int J Earth Sci 107:2409–2431, 2018), presents a computer simulation, which must be validated with field evidence and recent research in the area, and not based on assumptions, which have turned into facts over time. The discussors may be unfamiliar with the geological research that has been published over the last 20 years in the areas under consideration. Furthermore, the research on marine–non-marine evaporite formations is hardly considered in their discussion, yet much has been published.

Novel ceramics from waste material made of (x) paper ash–(80 − x) cullet–20 kaolin clay (10wt% ≤ x ≤ 30wt%) were successfully synthesized using a conventional solid-state reaction technique. Energy-dispersive X-ray analysis confirmed the presence of Si, Ca, Al, and Fe in the waste material for preparing these ceramics. The influence of the cullet content on the phase structures and the dielectric properties of these ceramics were systematically investigated. The impedance spectra were verified in the range from 1 Hz to 10 MHz at room temperature. The phase of the ceramics was found to primarily consist of wollastonite (CaSiO3), along with minor phases of γ-dicalcium silicate (Ca2SiO4) and quartz (SiO2). The sample with a cullet content of 55wt% possessed the optimum wollastonite structure and exhibited good dielectric properties. An increase of the cullet content beyond 55wt% resulted in a structural change from wollastonite to dicalcium silicate, a decrease in dielectric constant, and an increase in dielectric loss. All experimental results suggested that these novel ceramics from waste are applicable for electronic devices.

In the Russian school, the total normalized gradient method belongs to the most wide‐spread of direct interpretation methods for potential field data. This method was also used and partly developed by many experts from abroad. The main advantage of the total normalized gradient method is its relative independence of parameters such as the expected differential density of interpreted structures. The method is built from a construction of a specially transformed field (total normalized gradient) on a section crossing the potential field sources. The special properties of this transformed field allow it to be used to detect the source positions. From the 1960s, the mathematical basis of the method underwent enormous development and several modifications of the method have been elaborated. The total normalized gradient operator itself represents a relatively complicated, non‐linear band‐pass filter in the spectral domain. The properties of this operator can be handled by means of several parameters that act to separate the information about field sources at different depth levels. In this contribution, we describe the development of the method from its very beginning (based mostly on qualitative interpretation of simple total normalized gradient sections) through to more recent numerical improvements to the method. These improvements include the quasi‐singular points method, which refines the filter properties of the total normalized gradient operator and defines an objective criteria (so called criterion ‘α’ and ‘Г') for the definition of source depths in the section. We end by describing possibilities for further development of the method in the future.

We reformulate the original model of Hatchell and Bourne and Roste, Stovas and Landro that couples fractional velocity change to subsurface strain via a fundamental constant R. The new model combines elastic compressibility of a dual-porosity system for a sand–shale mixture with horizontal planes of inter-granular weakness. The majority of observed R-factor magnitudes from post-stack 4D seismic data in both the reservoir and overburden can thus be explained. R is predicted to depend strongly on lithology and also initial strain state. The model is also extended to predict the observed angle-dependence of time-lapse time-shifts from pre-stack data. An expression for the gradient of time-shift with incidence angle is obtained in terms of the background VP/VS, and also the ratio of tangential to normal compliances BT/BN representing loss or creation of inter-granular coupling. If accurately estimated from data, this compliance ratio can be used as an additional parameter to assess the post-production state of the overburden. It is concluded that whilst R remains the over-arching parameter controlling the magnitude of time-shifts measured from 4D seismic data, BT/BN is a subtler parameter that may also prove of future value.

This study shows the effect of calcination clay wastes from an art paper sludge for the use as supplementary cementing materials in blended cements. The starting clay sludge rich in kaolinite and talc was calcined at 600, 650 and 700 °C between 2 and 5 h, kaolinite was transformed into amorphous metakaolinite. This study reveals that calcination at 650 °C for 2 h is recommended to obtain a good supplementary cementing material for manufacture of blended cements., This research has been supported by the Autonomy Community of Madrid (project ref: GR/AMB/0448/2004) and, to Holmen Paper Madrid Company and T S Laboratory of Lafarge Cements (Toledo, Spain) for its technical support.

In Part I of this paper, we defined a focusing wave field as the time reversal of an observed point‐source response. We showed that emitting a time‐reversed field from a closed boundary yields a focal spot that acts as an isotropic virtual source. However, when emitting the field from an open boundary, the virtual source is highly directional and significant artefacts occur related to multiple scattering. The aim of this paper is to discuss a focusing wave field, which, when emitted into the medium from an open boundary, yields an isotropic virtual source and does not give rise to artefacts. We start the discussion from a horizontally layered medium and introduce the single‐sided focusing wave field in an intuitive way as an inverse filter. Next, we discuss single‐sided focusing in two‐dimensional and three‐dimensional inhomogeneous media and support the discussion with mathematical derivations. The focusing functions needed for single‐sided focusing can be retrieved from the single‐sided reflection response and an estimate of the direct arrivals between the focal point and the accessible boundary. The focal spot, obtained with this single‐sided data‐driven focusing method, acts as an isotropic virtual source, similar to that obtained by emitting a time‐reversed point‐source response from a closed boundary.

Publicación en versión online: 15 de noviembre de 2006, This work reports the project of thermal effects in mineralogy and texture of the paper sludge to employ them as pozzolanic material. For this reason, the chemistry and mineralogical composition has been studied, as well as its morphology by XRD, SEM and EDX. The initial sludge has been treated to 700, 750 and 800 °C during 2 and 5 h being observed that initial kaolinite becomes metakaolinite and that its pozzolanic activity with a paper sludge treated to 700 °C for 2 h is comparable to that of a commercial metakaolinite. The transformation of kaolinite after the dehydroxylation is to convert in amorphous metakaolinite. At the temperature mentioned above, calcite from the initial sludge is maintained active. It is concluded that the pozzolanic activity of metakaolinite is strongly related to the crystallinity of the original kaolinite. Well-ordered kaolinite is transformed into more reactive metakaolinite., This research has been supported by the Spanish Ministry of Science and Technology (project ref: MAT2003-06479-C03-01/02), Holmer Paper–Papelera Peninsular Company and TC laboratory of Lafarge.

This paper describes the results obtained from the application of a fuzzy expert system to the zonification of a deposit in terms of kaolin of a quality suitable for the paper and ceramic industries. In the first stage of the study, mineralogical, chemical and paper quality indices were characterized for samples taken from a kaolin deposit located in Galicia in NW Spain. In the second part of the study the expert system was trained and adjusted on the basis of analytical data, and its reliability in classifying samples in different quality groups was tested. Data analysis and the design and training of a fuzzy-logic expert system furnish the tool not only with general information inherent to kaolin mining but also with an input in the form of the local characteristics of the studied deposit. This method enables mining experts to identify the areas of a deposit containing kaolin that meets the criteria necessary for enrichment and subsequent use in the ceramic or paper industry. This kind of tool is not only indispensable in planning extraction tasks, but also permits technical and financial risk to be minimized. The model is innovative in that it automatically classified kaolin quality in terms of saleability, thereby emulating the logical reasoning processes of the human expert.

The first part of this paper analyses the influence of the molecular weight and concentration of carboxymethyl cellulose (CMC) and of kaolin concentration on rheology of the coating colours and on paper properties coated with ultra lightweight coatings (ULWC). In the second part, relationships between the rheological characteristics of the coating colour formulations and coated paper surface quality was also studied. New indexes on paper roughness at micro-scale are presented (RZI and SRI). In general, they show good correlation with sheet gloss. A new gloss index (SGI) is presented, accounting for the contribution of gloss from machine direction (MD) and cross direction (CD). Porosimetry was used to access microstructural characteristics in order to correlate them with light scattering and gloss properties. The former property is closely related to Hg intrusion volume of the coated layer while gloss is related to surface porosity with pore diameters in the range of 7–15 μm as measured by Hg intrusion volume.

Utilizing the assembly and formation of laponite/lauric arginate (LAE) complexes near the water-oil interface, where laponite and LAE interact, the stability and preparation of alkyl ketene dimer (AKD) Pickering emulsions with tunable shells were investigated. Stable spherical emulsions were generated with homogenization due to the interfacial jamming of laponite/LAE complexes. The packing density of laponite at the oil/water interface was adjustable via LAE concentration tuning. The Pickering system with a tunable shell, droplet size, resistance to oil agglomeration and hydrolysis over a long period of time was achieved based on LAE loading. Hydrophobic paper with a 126.6° of water contact angle was prepared under a surface sizing process with the laponite/LAE-stabilized AKD emulsion loading of 0.12 wt% LAE, which exhibited 90 days' long-term storage stability. The confocal laser scanning microscopy (CLSM) shows that laponite/LAE forms a dense layer at the oil/water interface and 3D-network in a continuous phase. The properties provided by laponite/LAE, a highly efficient complex with resistance to phase permeability and hydrolysis, open new opportunities in biodegradable and food-grade emulsifiers for paper sizing agents, where LAE achieves synergistic effects with laponite.