Monitoring aggregation processes in multiphase systems: a review

Particle aggregation is essential in many industrial processes, spanning the pharmaceutical and food industries, polymer production, and the environment, among others. However, aggregation can also occur, in some processes, as a non-desired side effect. Thus, to be able to monitor aggregation in industrial processes is of high importance to guarantee that the final, required product characteristics are obtained. In this paper, we present an extensive review of the different techniques available for monitoring particle characteristics in industrial processes involving particulate materials, with special emphasis on aggregation processes. These methods include both off-line and on-line techniques, based either on image acquisition techniques or different radiation scattering techniques (light-scattering and ultrasound spectroscopy). The principles behind each technique are addressed, together with their relevant applications, advantages, and disadvantages

On hair care physicochemistry: From structure and degradation to novel biobased conditioning agents

Hair is constantly exposed to various adverse external stimuli, such as mechanical or thermal factors, that may cause damage or cause it to lose its shine and smooth appearance. These undesirable effects can be minimized by using hair conditioners, which repair the hair and restore the smooth effect desired by the consumer. Some of the currently used conditioning agents present low biodegradability and high toxicity to aquatic organisms. Consumers are also becoming more aware of environmental issues and shifting their preferences toward natural-based products. Therefore, developing novel, sustainable, natural-based derivatives that can act as conditioning agents in hair care products and thus compete with the traditional systems obtained from non-renewable sources is highly appealing. This paper presents the key physicochemical aspects of the hair conditioning process, including hair structure and degradation, and reviews some of the new alternative conditioning agents obtained from natural resources.info:eu-repo/semantics/publishedVersio

Extraction and characterization of microplastics from portuguese industrial effluents

Microplastics (MPs) are contaminants present in the environment. The current study evaluates the contribution of different well-established industrial sectors in Portugal regarding their release of MPs and potential contamination of the aquifers. For each type of industry, samples were collected from wastewater treatment plants (WWTP), and different parameters were evaluated, such as the potential contamination sources, the concentration, and the composition of the MPs, in both the incoming and outcoming effluents. The procedures to extract and identify MPs in the streams entering or leaving the WWTPs were optimized. All industrial effluents analysed were found to contribute to the increase of MPs in the environment. However, the paint and pharmaceutical activities were the ones showing higher impact. Contrary to many reports, the textile industry contribution to aquifers contamination was not found to be particularly relevant. Its main impact is suggested to come from the numerous washing cycles that textiles suffer during their lifetime, which is expected to strongly contribute to a continuous release of MPs. The predominant chemical composition of the isolated MPs was found to be polyethylene terephthalate (PET). In 2020, the global need for PET was 27 million tons and by 2030, global PET demand is expected to be 42 million tons. Awareness campaigns are recommended to mitigate MPs release to the environment and its potential negative impact on ecosystems and biodiversity.info:eu-repo/semantics/publishedVersio

Application of Different Low-Reynolds k-ɛ Turbulence Models to Model the Flow of Concentrated Pulp Suspensions in Pipes

AbstractIn the pulp and paper industry, the design of industrial equipment based on empirical correlations can be avoided using Computational Fluid Dynamics (CFD) tools. The present study aims at investigation of the turbulent pipe flow of concentrated Eucalyptus pulp suspension using the ANSYS FLUENT® CFD software package. The modelling strategy was a pseudo-homogeneous approach. The non-Newtonian behavior of the pulp suspension was introduced into the CFD code considering its viscosity as a function of a shear rate. Additionally, the existence of a water annulus at the pipe wall surrounding the core flow was taken into account. Four low-Reynolds k-ɛ turbulence models were selected in the present study aiming at describing the presence of a drag reduction effect. All the models used were able to reproduce the drag reduction effect. Additionally the Lam-Bremhorst model was modified taking into account alterations applied successfully by other authors for the turbulent flow of polymer solutions. A good correspondence between the peculiar S-shaped profile near the wall, for the dimensionless velocity, reported in literature for these systems and those obtained numerically was achieved. The approach followed was validated by comparing the numerical results of pressure drop with those from literature

Effect of the dispersion state of minerals on the properties of cellulose nanofiber-based composite films

The dispersion state and the efficiency of the mixture of the different components in a composite film have an important impact on its mechanical and optical properties. In the present work, the impacts of different dispersion treatments on the disaggregation state of fibrous clay particles in water, and on the properties of related cellulose nanofiber (CNF)-based composite films, were evaluated. X-ray diffraction studies, performed on samples of sepiolite and palygorskite, revealed only minor changes in the diffraction pattern when the minerals were subjected to ultrasonic treatment, with or without the addition of different chemical dispersing agents. Conversely, microscopic studies revealed important differences in the dispersion state of the samples, induced by the addition of the different dispersants, showing an improvement in the disaggregation of the mineral crystals. The composite films prepared with sepiolite (and carboxymethylcellulose, as chemical dispersant) dispersed using ultrasonic treatment, and different types of CNF, showed improved optical and mechanical properties when compared with composites of the same counterparts prepared with sepiolite dispersed using a high-speed shear disperser.info:eu-repo/semantics/publishedVersio

Microplastics in ecosystems: from current trends to bio-based removal strategies

Plastics are widely used due to their excellent properties, inexpensiveness and versatility leading to an exponential consumption growth during the last decades. However, most plastic does not biodegrade in any meaningful sense; it can exist for hundreds of years. Only a small percentage of plastic waste is recycled, the rest being dumped in landfills, incinerated or simply not collected. Waste-water treatment plants can only minimize the problem by trapping plastic particles of larger size and some smaller ones remain within oxidation ponds or sewage sludge, but a large amount of microplastics still contaminate water streams and marine systems. Thus, it is clear that in order to tackle this potential ecological disaster, new strategies are necessary. This review aims at briefly introducing the microplastics threat and critically discusses emerging technologies, which are capable to efficiently clean aqueous media. Special focus is given to novel greener approaches based on lignocellulose flocculants and other biomaterials. In the final part of the present review, it was given a proof of concept, using a bioflocculant to remove micronized plastic from aqueous medium. The obtained results demonstrate the huge potential of these biopolymers to clean waters from the microplastics threat, using flocculants with appropriate structure.UIDB00102/2020/ UIDB/05183/2020/ PTDC/AGR-TEC/4814/2014/ PTDC/ASP-SIL/30619/2017/ CEECIND/01014/2018info:eu-repo/semantics/publishedVersio

Acacia wood fractionation using deep eutectic solvents: extraction, recovery, and characterization of the different fractions

The selective extraction and recovery of different lignocellulosic molecules of interest from forestry residues is increasing every day not only to satisfy the needs of driving a society toward more sustainable approaches and materials (rethinking waste as a valuable resource) but also because lignocellulosic molecules have several applications. For this purpose, the development of new sustainable and ecologically benign extraction approaches has grown significantly. Deep eutectic solvents (DESs) appear as a promising alternative for the processing and manipulation of biomass. In the present study, a DES formed using choline chloride and levulinic acid (ChCl:LA) was studied to fractionate lignocellulosic residues of acacia wood (Acacia dealbata Link), an invasive species in Portugal. Different parameters, such as temperature and extraction time, were optimized to enhance the yield and purity of recovered cellulose and lignin fractions. DESs containing LA were found to be promising solvent systems, as the hydrogen bond donor was considered relevant in relation to lignin extraction and cellulose concentration. On the other hand, the increase in temperature and extraction time increases the amount of extracted material from biomass but affects the purity of lignin. The most promising DES system, ChCELA in a ratio of 1:3, was found to not significantly depolymerize the extracted lignin, which presented a similar molecular weight to a la-aft lignin. Additionally, the P-31 NMR results revealed that the extracted lignin has a high content of phenolic OH groups, which favor its reactivity. A mixture of ChCl:LA may be considered a fully renewable solvent, and the formed DES presents good potential to fractionate wood residues.info:eu-repo/semantics/publishedVersio

Eco-friendly methods for extraction and modification of cellulose: an overview

Cellulose is the most abundant renewable polymer on Earth and can be obtained from several different sources, such as trees, grass, or biomass residues. However, one of the issues is that not all the fractionation processes are eco-friendly and are essentially based on cooking the lignocellulose feedstock in a harsh chemical mixture, such as NaOH + Na2S, and water, to break loose fibers. In the last few years, new sustainable fractionation processes have been developed that enable the obtaining of cellulose fibers in a more eco-friendly way. As a raw material, cellulose’s use is widely known and established in many areas. Additionally, its products/derivatives are recognized to have a far better environmental impact than fossil-based materials. Examples are textiles and packaging, where forest-based fibers may contribute to renewable and biodegradable substitutes for common synthetic materials and plastics. In this review, some of the main structural characteristics and properties of cellulose, recent green extraction methods/strategies, chemical modification, and applications of cellulose derivatives are discussed.BDE 05|POCI-01-0247-FEDER021874; 2022.07519.PTDCinfo:eu-repo/semantics/publishedVersio

ITs in engineering education: joining efforts between SPEE and IGIP

The International Society for Engineering Education (IGIP) and The Portuguese Society for Engineering Education (SPEE), the first being the oldest European Society for Engineering Education in Europe and the second the very young Society for Engineering Education in Portugal, have been intensifying the collaboration between the two societies as well as the exchange and dissemination of information about their relevant activities, whilst promoting understanding and cooperation between their respective members. One possible way is to create joint working groups, open to the members of both societies, on common topics of interest. In fact, both societies already kicked off this activity. The first initiative happened during the 1st World Engineering Education Flash Week (WEE), Lisbon, 2011. The SPEE-IGIP Flash Moment was a one day event integrated in the main Conference, which was dedicated to “Information & Communication Technologies in Engineering Education”. ITs allow the development of different teaching strategies which contribute to enhance the learning outcomes of students. ITs are also particularly suited to develop Life Long Learning tools, in a broad range of Engineering subjects, either open to the general market or oriented to a very specific public. Examples of teaching strategies involving ITs have been addressed during the Flash Moment SPEE-IGIP which took place during WEE, and some are described in detail in the present work

MAMMALS IN PORTUGAL : A data set of terrestrial, volant, and marine mammal occurrences in P ortugal

Mammals are threatened worldwide, with 26% of all species being includedin the IUCN threatened categories. This overall pattern is primarily associatedwith habitat loss or degradation, and human persecution for terrestrial mam-mals, and pollution, open net fishing, climate change, and prey depletion formarine mammals. Mammals play a key role in maintaining ecosystems func-tionality and resilience, and therefore information on their distribution is cru-cial to delineate and support conservation actions. MAMMALS INPORTUGAL is a publicly available data set compiling unpublishedgeoreferenced occurrence records of 92 terrestrial, volant, and marine mam-mals in mainland Portugal and archipelagos of the Azores and Madeira thatincludes 105,026 data entries between 1873 and 2021 (72% of the data occur-ring in 2000 and 2021). The methods used to collect the data were: live obser-vations/captures (43%), sign surveys (35%), camera trapping (16%),bioacoustics surveys (4%) and radiotracking, and inquiries that represent lessthan 1% of the records. The data set includes 13 types of records: (1) burrowsjsoil moundsjtunnel, (2) capture, (3) colony, (4) dead animaljhairjskullsjjaws, (5) genetic confirmation, (6) inquiries, (7) observation of live animal (8),observation in shelters, (9) photo trappingjvideo, (10) predators dietjpelletsjpine cones/nuts, (11) scatjtrackjditch, (12) telemetry and (13) vocalizationjecholocation. The spatial uncertainty of most records ranges between 0 and100 m (76%). Rodentia (n=31,573) has the highest number of records followedby Chiroptera (n=18,857), Carnivora (n=18,594), Lagomorpha (n=17,496),Cetartiodactyla (n=11,568) and Eulipotyphla (n=7008). The data setincludes records of species classified by the IUCN as threatened(e.g.,Oryctolagus cuniculus[n=12,159],Monachus monachus[n=1,512],andLynx pardinus[n=197]). We believe that this data set may stimulate thepublication of other European countries data sets that would certainly contrib-ute to ecology and conservation-related research, and therefore assisting onthe development of more accurate and tailored conservation managementstrategies for each species. There are no copyright restrictions; please cite thisdata paper when the data are used in publications.info:eu-repo/semantics/publishedVersio