Search

A large amount of wool produced in the EU region is coarse and of low quality. The limited or nonutilization of such coarse wool leads to landfilling causing environmental pollution. In this paper, we studied the properties of keratin hydrolyzate, produced by a sustainable hydrolysis process, to be used as a foaming agent in foam dyeing of cotton and wool fabrics. This is a preliminary step on the way to find possible applications which overcome the environmental problem of wool waste and byproducts. We report for the first time the use of keratin hydrolyzate as a foaming auxiliary in the textile dyeing process. The surface tension, molecular weight, foam stability, blow ratio, and bubble size of keratin hydrolyzate in aqueous solutions with and without dyeing auxiliaries were determined. The dyeing influential parameter such as wet pickup was studied to identify their effect on dye fixation and color strength. The foam dyeing was compared with conventional cold-pad batch and pad-steam processes for cotton and wool, respectively. In the investigated variant, keratin hydrolyzate shows a reduction in surface tension, good foam stability along with dyeing auxiliaries, a blow ratio of about 10:1, and 0.02-0.1 mm diameter bubble sizes. These results make possible its application as a foaming agent. Cotton and wool fabrics were dyed using reactive and acid dyes respectively, on a horizontal padding mangle. In both cases, hydrolyzed keratin acts as a carrier for dye molecules and the mechanism of dyeing depends on the respective pH of the dye solution, keratin, and fiber. Foam dyeing of cotton resulted in comparable color strength, while wool shows higher color strength when compared with conventional dyeing processes. Washing and rubbing fastness of cotton and wool foam dyed fabrics are similar to the respective conventional dyed fabrics. The combinations of sustainable keratin hydrolyzate production and its use as an eco-friendly, biodegradable foaming agent in less add on foam dyeing technology resulted not only in saving of large amounts of water and energy but also will be helpful in minimizing a load on effluent and the environment.

A noticeable amount of dyes may remain in the wastewater downstream of dyeing facilities giving anaesthetic colorations as well as environmental concern. Conventional biological treatment alone cannot guarantee a sufficient decolouration and tertiary treatments have to be necessarily considered. Two oxidation schemes by ozone were considered in this work. A bubble column reactor (as a benchmark, in agreement with industrial applications) and a recycle well-mixed reactor were compared to reach the highest decolouration of standard dyes. In addition, hydrodynamic and ultrasonic cavitation were considered in the recycled well-mixed reactor to intensify its performance. The decolouration analysis was carried out for two dye classes (reactive and disperse), characterized by very different physical and chemical features. It appeared that some benefit was brought by ultrasound cavitation in the case of disperse dye only, while the degradation of the reactive dye was not intensified by the above hydraulic phenomenon. Ozone treatment was protracted to obtain different decolouration degrees of wastewater generated by wool dyeing. The resulting water was tested as a recycled process fluid to prepare fresh dyeing liquors, where devising the minimum decolouration degree became one of the quality specifications for recycling water back to dyeing. This article is protected by copyright. All rights reserved

The purpose of this work was to present a methodology to assess the energy consumption, specifically the energy utilized in the washing and drying processes, of textile products in their use-phase with the help of statistical tools. Regardless of the environmental impacts associated with the use-phase of textile products, analysis of energy consumption in that phase is still lacking. There is a need to design methodology for identifying the hotspots and parameters influencing the energy consumption in the use-phase of textile products. A pragmatic method that consists of a life-cycle assessment (LCA) framework plus principle component analysis (PCA), extended by Procrustes analysis (PA), is used to determine the energy consumption and minimize the possible uncertainties in the use-phase of textile product systems. The LCA plus PCA-PA method employed in this work to analyze the energy consumption of textile products in the use-phase comprises two statistical tools. First, PCA was applied to find the key parameters affecting the results. As an extension of PCA, PA was performed to highlight the most prominent variables within the dataset and extract the maximum amount of information. Lastly, hierarchical cluster analysis (HCA) was utilized for the classification of textile products on the basis of energy consumption variables and the similarity of their results. Among various energy consuming parameters in the use-phase of a textile product, both geographical and physical aspects can be prominent variables that significantly can affect the results of the energy consumption. After the LCA plus PCA-PA methodology, country of the use-phase in the geographical aspect and in the physical aspect, the fiber type and weight of the products were the influential variables. Hotspots or influential parameters being identified, a number of steps can be taken that can play an important role in decreasing environmental impacts by reducing the energy consumption in the laundering process of textile products during the use-phase. The methodology of LCA plus PCA-PA for energy consumption in textile products was employed to study the gap in currently available assessments. Using this method, the main influencing energy consuming parameters or hotspots in the use-phase of a textile product system could easily be identified and potential improvements of sustainability can be proposed.

The present study focuses on the use of N-methylformanilide as swelling agent in the dyeing process of meta-aramid fibers. Fiber dyeability with a cationic dye (C.I. Basic Blue 41) has been examined at three different N-methylformanilide concentrations: in particular, adsorption isotherms, dyeing kinetics and fastness to washing and rubbing have been investigated. The experiments have been carried out in a batch system to optimize initial dyestuff concentration, swelling agent concentration and dyeing time. Langmuir, Freundlich and Temkin adsorption isotherms have been used to model equilibrium data. It was found that Freundlich model agreed very well with experimental data: the correlation coefficients ranged from 0.97 to 0.99. The adsorption kinetics has been discussed in view of two kinetics models, i.e. the first-order Lagergren's model and a pseudo-second order model. The pseudo-first order kinetics model describes Basic Blue 41 adsorption on meta-aramid fiber very well. From the technological point of view, 5% on weight fiber (o.w.f.) of Basic Blue 41 and 60% o.w.f. of N-methylformanilide has been found to be adequate to obtain a deep and uniform hue. All dyeing conditions provide satisfactory fastness properties.

It is well established that current flame retardant (FR) products at disposal generate various ecological hazards. Irrespective of their environmental impacts, the FR market is growing and is estimated to reach 2.8 million tons globally in 2018. In the textile domain, FRs are incorporated into baby clothing, pushchairs, car seats, etc. When disposed, these FR textile products end up in a landfill or are incinerated. These disposal processes are unsustainable. With landfilling, there is a huge chance of the FR product leaching into the environment. Similarly, FRs decrease energetic yields in the incineration process due to incomplete combustion. To cope with such issues, degradation and elimination of the FR product from the textile products before disposal could be a sustainable alternative. This study dealt with the preliminary degradation of flame retardant from the cotton textiles and its thermal characterization. Energy valorization by gasification is considered beneficial opposed to incineration with overall low energy recovery. The initial optimum gasification conditions including FR-treated cotton as a feeding material and potential outcomes of FR-treated cotton after degradation were characterized.

Renewable energy from thermal valorization plays a key part in today&rsquo, s energy from natural cellulosic textiles that are resourceful biomass and safe from toxicity at high temperature treatments. The situation is opposite, when technical textiles are treated with synthetic chemical finishes adding functionality as anti-bacterial, water repellent or flame retardant, etc. Incineration of flame retardant textile results in possible unfavorable gases, toxic fumes and contaminated ash. Other thermal valorization techniques like gasification would assist in avoiding the formation of additional toxic hazards. Herein, gasification of flame retardant textile is carried out the likelihood to get quality gas composition. For comparative analysis, flame retardant textiles, after their flame retardant ability being revoked, are also gasified. The output gas components suggested that gasification can be a useful thermal valorization approach for flame retardant textiles and relevantly improved gas composition was seen in textiles with their flame retardant substrate/species being removed.

The present work aims to study the effect of the liquid temperature on the performance of ultrasounds (US) in a dyeing process. The approach was both theoretical and experimental. In the theoretical part the simplified model of a single bubble implosion is used to demonstrate that the "maximum implosion pressure" calculated with the well known Rayleigh-Plesset equation for a single bubble can be correlated with the cavitation intensity experimentally measured with an Ultrasonic Energy Meter (by PPB Megasonics). In particular the model was used to study the influence of the fluid temperature on the cavitation intensity. The "relative" theoretical data calculated from the implosion pressure were satisfactorily correlated with the experimental ones and evidence a zone, between 50 and 60°C, were the cavitation intensity is almost constant and still sufficiently high. Hence an experimental part of wool dyeing was carried out both to validate the previous results and to verify the dyeing quality at low temperatures (40-70°C) in presence of US. A prototype dyeing equipment able to treat textile samples with US system of 600W power, was used. The dyeing performances in the presence and absence of US were verified by measuring ΔE (colour variation), Re,% (reflectance percentage), K/S (colour strength) and colour fastness. The US tests performed in the temperature range of 40-70°C were compared with the conventional wool dyeing at 98°C. The obtained results show that a temperature close to 60°C should be chosen as the recommended US dyeing condition, being a compromise between the cavitation intensity and the kinetics which rules the dyestuff diffusion within the fibres.

Dyeing processes of various yarns (wool, cotton, polyester, nylon 6 and acrylic) were studied with the aim to substitute some auxiliary agents with ethanol at low concentration. The results observed in isothermal dyeing showed a favorable effect of alcohol addition, at about 1–3% v/v, on the dye uptake, with some differences depending on fiber nature and dye class. This effect was correlated with contact angle measurements of water-ethanol solutions on the mentioned yarns, which confirmed a lower surface tension in the same concentration range. Then, laboratory tests with dye triads at programmed temperature were carried out comparing the results of standard dyeing recipes with those obtained by replacing wetting, retardant and leveling agents with ethanol. Good color imitations were generally shown with respect to standard processes. A wetting effect of ethanol was shown for all the tested yarns and dye classes, while in wool dyeing with acid, pre-metallized and reactive dyes, ethanol was suitable to replace also leveling and retarding agents. Light and wash fastnesses were also compared. Finally the environmental benefits arising from chemical substitution of auxiliary agents with ethanol were highlighted and the cost of alcohol introduction was compared with the cost saving of auxiliary substitution. A positive economic balance was obtained.

Wastewater from textile industry usually undergoes activated sludge biotreatment ahead of refining treatments, final discharge or reuse. To identify the most effective bioreactor typology for the secondary treatment of a wastewater resulting from a textile industry of the Biella district (Italy), four pilot units characterized by a different configuration and fluid dynamics (i.e., Bioflotation®, Fixed Bed Biofilm Reactor (FBBR), flow-jet aeration and standard aerobic sludge reactors) were operated in parallel, inoculated with the same microbial consortium and fed with identical streams of wastewater discharged from wet textile processes of the industy. COD, TC and non-ionic surfactants were monitored in effluents of the compared bioreactors working under continuous mode and the cultivable heterotrophic microorganisms prevailing in each of them were isolated and characterized as the end of the study. The results demonstrated that the air supply system greatly influenced the treatment efficiency which reached the highest value in the case of Bioflotation® and FBBR technology. A highly specialized bacterial biomass mostly composed by strains of the Pseudomonas, Stenotrophomonas and Ochrobactrum genera was isolated in such reactors, thus suggesting that a direct correlation between reactor configuration, decontamination performances and microbial biomass composition exist.

An atmospheric pressure plasma jet (APPJ) for continuous treatment of polymeric films and textile materials was investigated to characterize its thermal, hydrodynamic and chemical features. The operative variables of the plasma jet equipment are: gas flow rate and composition, electrical power to the plasma generator and fabric velocity. A diagnostic evaluation of the equipment was carried out to improve the treatment homogeneity and generate an effective feedback for scale-up. The cross profile of gas temperature and velocity, the fabric temperature and concentration transitory in the gas system generated by a reverse step of oxygen were determined. These measurements showed that the original prototype configuration required a better gas distribution to fully demonstrate its potentiality to functionalize textiles. The surface modifications induced by plasma were detected by processing wool fabrics and by evaluating the treatment benefit on dyeing.

The infusion of high purity Factor VIII and Factor IX concentrates represent one of the best alternatives in the treatment of haemophilia A and haemophilia B respectively. Among the dehydration techniques, freeze-drying is considered as the reference process preserving biological activity and, consequently, it is utilised for manufacturing high-quality pharmaceutical products. The aim of this work was to study the influence of the freezing and the drying conditions on the final quality of both freeze-dried high purity Factor VIII and Factor IX concentrates. The biological activity of both Factor VIII and Factor IX was not influenced by the freezing rates and, considering the experimental conditions that led to uncollapsed products, by the drying rates studied. Moreover, according to other previous works and to the industrial experience, no remarkable difference on their biological activities depending on the freezing and primary drying conditions was noticed for both factors. From these results, a new optimised cycle that permitted to reduce considerably the duration of the freeze-drying process, was defined. The freeze-dried products obtained had a relative biological activity in line with the actual industrial standards, were good rehydratable and showed a stability of at least 1 month at +4 °C.

The effect of different lyoprotectants (sucrose, dimethyl-succinate buffer (DMS), bovine serum albumin (BSA), mannitol and dextran, mw 60 kDa) on the stability of the enzyme lignin peroxidase (LiP, EC number: 1.11.1.-), both during the freeze-drying process and storage were investigated. The shelf stability tests were performed at 4 °C and 27 °C. Both DMS buffer and sucrose showed a good protective action: the former was particularly effective during the process, while the latter improved the stability during storage. In contrast, mannitol and dextran had negative effects, reducing the activity also in the lignin peroxidase solution. BSA was discarded because, in the range of compatible concentrations with LiP, it does not confer a consistent structure to the freeze-dried product. © 2002 Society of Chemical Industry

The [Formula: see text]-methylol dimethyl phosphono propionamide (MDPA) flame retardant compounds are predominantly used for cotton fabric treatments with trimethylol melamine (TMM) to obtain better crosslinking and enhanced flame retardant properties. Nevertheless, such treatments are associated with a toxic issue of cancer-causing formaldehyde release. An eco-friendly finishing was used to get formaldehyde-free fixation of flame retardant to the cotton fabric. Citric acid as a crosslinking agent along with the sodium hypophosphite as a catalyst in the treatment was utilized. The process parameters of the treatment were enhanced for optimized flame retardant properties, in addition, low mechanical loss to the fabric by response surface methodology using Box–Behnken statistical design experiment methodology was achieved. The effects of concentrations on the fabric’s properties (flame retardancy and mechanical properties) were evaluated. The regression equations for the prediction of concentrations and mechanical properties of the fabric were also obtained for the eco-friendly treatment. The R-squared values of all the responses were above 0.95 for the reagents used, indicating the degree of relationship between the predicted values by the Box–Behnken design and the actual experimental results. It was also found that the concentration parameters (crosslinking reagents and catalysts) in the treatment formulation have a prime role in the overall performance of flame retardant cotton fabrics.

Wet textile washing processes were set up for wool and cotton fabrics to evaluate the potential of ultrasound transducers (US) in improving dirt removal. The samples were contaminated with an emulsion of carbon soot in vegetable oil and aged for three hours in fan oven. Before washing, the fabrics were soaked for 3 min in a standard detergent solution and subsequently washed in a water bath. The dirt removal was evaluated through colorimetric measurements. The total color differences ΔE of the samples were measured with respect to an uncontaminated fabric, before and after each washing cycle. The percentage of ΔE variation obtained was calculated and correlated to the dirt removal. The results showed that the US transducers enhanced the dirt removal and temperature was the parameter most influencing the US efficiency on the cleaning process. Better results were obtained at a lower process temperature.

Flow regimes in gas–solid fluidisation are presented on a broad scale from captive smooth fluidisation to dilute transport. The parameters useful to identify each transition are critically presented. The description of catalytic gas–solid fluidised beds is considered starting from simplified two-phase models; a third phase given by clouds and wakes is then introduced to justify their effect in promoting solids circulation. Different hydrodynamic features have been used in the literature to describe the dense and the dilute phase, according to the mixing effect of bubbles. Circulating fluidised bed modelling is approached according to the definition of a hydrodynamic regime. The numerous models appearing up to now in literature are presented, from earlier homogeneous models to the latest continuous radial profile and clustering models. The development of spouted beds as chemical reactors is given from the first fundamental approach, followed by the experimentation in the late 1970s, ending with more complex descriptions that take into account all the spouted bed zones. A concluding chapter on model selection offers general criteria to tackle the mathematical description which predicts the performance of catalytic reactors in the different regimes.

Spouted beds appear to go through a revival, testified by a very recent and comprehensive book on the topic (Epstein & Grace, 2011). This renewed interest arises by implementing new concepts in scaling-up spouting contactors and devising potential applications to high temperature processes, noticeable examples being given by pyrolysis and gasification of biomass, kinetically controlled drying of moist seeds to guarantee the requested qualities and polymer upgrading processes.

In an earlier review on modeling of catalytic gas–solid fluidized bed reactors, spouted beds were treated as a special case of fluidized beds, with the jet region extending to the upper free surface of the solids emulsion. The spout and the annulus are two well-distinguished zones, characterized by such different gas–solid contacting that they have been treated distinctly since the first approach for modeling spouted bed chemical reactors. The spout zone acts as a dilute vertical transport system, whereas the peripheral annulus has many similarities with a countercurrent downflow packed bed, the major peculiarity being gas percolation into the dense emulsion from the spout. Therefore, solids motion in a spouted bed is a major factor affecting mass and heat transfer, mixing, contacting, and hence the choice of reactor model. The solids can react (e.g., in combustion, where they are depleted over time), constitute inerts (e.g., sand diluting a solid fuel and regulating the system hydrodynamics, as well as providing a heat buffer), or act as a catalyst. Successful design and operation of a reactor depend on the ability to predict the system behavior, especially the hydrodynamics, mixing of individual phases, heat and mass transfer rates, and kinetics of the reactions involved.

A continuous autothermal two-stage pyrolysis/partial combustion process has been tested at the bench scale. Coal (or oil shale) up to 5 kg/h is fed to a spouted bed pyrolyzer in which the volatiles are driven off for tar recovery. Part of the resulting char is passed to a spouted bed partial combustor which produces the hot flue gas to provide heat and a spouting medium in the pyrolyzer. The two reactors are placed in a compact vertical configuration. The process is tested on two coals of different rank, and on oil shale. The effect of prime operating variables on yield are established and a number of operating modes demonstrated.

An apparatus to dry aqueous dispersions of solid lipid nanoparticles (SLNs) was designed. Optimal running conditions were evaluated to obtain minimum process time and produce dried SLNs characterized by small size variation. To achieve process optimization, SLN average diameter, SLNs polydispersity index, and drying time were related to three operative variables: process temperature, SLN concentration in the original aqueous dispersions, and nitrogen flow rate as the physical means of the drying process. An experimental design procedure and a multicriteria optimization method, targeting desirability functions, enabled us to obtain the optimal conditions for all responses. Drying time, average diameter, and polydispersity index of dried SLN batches were more favorable than those obtained by freeze-drying identical SLN aqueous dispersions with the same initial nanoparticle concentration.

Solid lipid nanoparticles (SLNs) have been proposed as alternative colloidal drug carriers. SLNs are obtained by dispersing warm oil-in-water microemulsions into cold water. The aim of this research was to investigate an evaporative drying process for aqueous dispersions of SLNs. For this purpose, a special apparatus, namely a thermostatic minidesiccator having alumina as the drying medium, was designed to carry out the evaporative drying at a controlled temperature. Besides the water removal kinetics, the mean particle size and the size distribution of SLNs were measured during the during with the aim of detecting the highest temperature at which the drying process can be carried out without significantly affecting the SLN average diameter. The SLN dispersions were evaluated with and without a hydrophilic excipient, commonly used as a cryoprotector (trehalose). The drying temperature of 10 degrees C was found to be the most suitable for obtaining SLNs as a powder, maintaining almost the same size as that of the SLNs in dispersion.

Freeze-drying is the process whereby a solvent (usually water) is removed from a frozen solution or a frozen foodstuff by sublimation. Since freeze-dry In this study, the lyophilization process was carried out on a frozen solution of cloxacillin monosodium salt using a pilot plant. Experimental drying A physical model is proposed for heat transfer between the heating plate and the tray containing the product, based on Knudsen conduction in a thin lay

A plain-weave wool fabric has been treated in a roll-to-roll atmospheric pressure, post-discharge plasma equipment at three fabric speeds. The thermal properties of the treated fabric have been investigated by means of an Alambeta instrument. The thermal resistance and thermal diffusivity increased after the plasma treatment while the thermal absorptivity and volumetric heat capacity decreased. The longer the plasma-to-fabric exposure time, the more marked the change in the fabric's thermal properties. Since thermal conductivity was unaffected after the treatment, the thermal properties changed due to the increase in thickness that was observed after the plasma treatment. A validated model has been used to predict the human psychophysical perception of the fabric hand. As a consequence of the more voluminous structure, a softer and warmer hand has been predicted for the treated fabrics compared to the untreated ones.

Previously reported experimental work on the decomposition of ozone in a 0.15 m diameter spouted bed of angular iron oxide catalyst particles has been extended to spherical catalyst particles in both 0.15 m and 0.22 m dia. columns. Other variables, aside from column diameter, included catalyst particle size, bed depth, spouting velocity, and reaction rate constant (varied by adjusting the bed temperature). The use of a photometric analyser allowed analysis of concentrations at the inlet and exit from the bed, at different radial positions at the bed surface, and at several positions within the bed itself. Very little effect of particle size was found over the range studied (2.58 to 4.38 mm). Contrary to previous expectations, the conversion was found to decrease as the bed diameter was increased. The concentration gradients observed in the annulus indicate that the streamtube model is superior to the one-dimensional model, despite the fact that overall conversions predicted by these previously derived models are again similar. The observed gradients were not, however, as pronounced as those predicted by the streamtube model, and this suggests that radial dispersion in the annulus cannot be entirely neglected.

Segregation of solid materials, differing in density, was detected at the surface of the annulus of a spouted bed when a baffle, preventing mixing with solids from the fountain, was placed above an overflow pipe. Concentrations higher than 90% by volume in the light material could be obtained in the continuous discharge stream from a well mixed bed having an overall light-solids concentration as low as 3%. The gas velocity in the annulus, exceeding the minimum fluidization velocity of the light component, was shown to be the mechanistic explanation of the phenomenon. On a decele une segregation de matieres solides de densites differentes au sommet de l'anneau d'un lit “spoute”, lorsqu'on place une chicane qui empche le melange avec des matieres solides provenant de la fontaine, au-dessus d'un tuyau de trop-plein. On a pu obtenir, pour le materiau leger, des concentrations excedant 90% en volume, dans le courant continu de decharge a partir d'un lit bien melange, dont la concentration globale des matieres solides legeres etait aussi faible que 3%. On montre que le fait que la vitesse du gaz dans l'anneau excede la vitesse minimale de fluidisation est une explication mecanistique du phenomene.

The cause of segregation at the discharge in a continuously operating spouted bed has been investigated. Radial concentration profiles of the coarse component have been detected in a two-component mixture of glass ballotini at different spouting regimes, at different bed levels and discharging from openings at several bed depths. The annulus of a spouted bed has been shown to move in a fashion close to a plug flow without altering the concentration gradients existing below the bed free surface. Consistent with previous results, percolation induced segregation was negligible under these experimental conditions. The concentration existing at the column wall has been shown to be identical to that in the outgoing stream of solids and segregation phenomena at the outlet cannot explain a discharge composition different from the mean concentration in the bed. The particle trajectories in the fountain are believed to be responsible for the radial concentration gradient in the annulus of the spouted bed.

The residence time distribution function (RTDF) of a gas was measured in a gas—liquid stirred contactor with coalescing and non-coalescing systems using a gaseous tracer. It was found that the influence of the tracer solubility, even for a compound of very low solubility, was an important parameter which caused very long tails to the response curves. A methodology for the accurate evaluation of this effect was developed. The experimental results show that part of the gas moves in a plug-flow manner, this part depending on the gas—liquid hydrodynamic regime; the data can be satisfactorily interpreted by using a model which considers the partial recycling of the gas phase in the stirrer zone.

A detailed comparative analysis was carried out on freeze-drying coupled with an evaporative freezing and a conventional freezing step, using on-line monitoring of several fruit and vegetable weights vs. time. The experimental work was based on the use of two weighing cells: a traditional one and a prototype capacitive balance. The work showed that process rates differed because of product texture, water and sugar content, cooling temperature and freezing velocity. Different water release mechanisms were identified.

A continuous gelation process for producing aluminum and zirconium hydroxide microparticles was conceived and tested in a lab-scale apparatus. Fluidized state was devised as an appropriate hydrodynamic configuration to maintain the reacting sol microdrops suspended: stable non-coalescing spherical gel particles in a size range quite below 100 μm were produced via gelation. The microspheres produced by a subsequent calcination step showed a diameter ranging between 2 μm and 20 μm. This powder, without further size classification, was an optimal product to manufacture test specimens by sintering. Measurements on the mechanical properties, such as toughness, flexural strength and hardness, classified the test bars as a very promising ceramic material. In order to enlighten the chemical drying phenomenon and devise the main governing mechanisms acting in the gelation reaction, an extremely simplified experimental system was set. A single drop of sol was deposited into a given amount of the dehydrating liquid medium and observed by an optical microscope; image analysis permitted us to identify the gel formation, the size reduction kinetics, as well as secondary phenomena.