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Additive technologies currently represent progressive technologies, both in the field of manufacturing itself and in materials engineering, where the main source is powder material. Powder material as a source material is characterized by the mechanical, physical and flow properties of fine powders. Targeted modification of these properties represents a research challenge in this area with the aim of creating a granulate with the required properties. This article compares selected mechanical, physical and flow properties of the original powder material used for 3D printing with the created granulate. The granulate was created by a process of high-pressure compaction between the rolls of a compactor and subsequent dry granulation on a patented flat-die granulator to create a granulate with a narrow particle size distribution. The result is an assessment of the improvement in flow properties for possible material recycling and reuse of the raw material for further processing using 3D printing. [ABSTRACT FROM AUTHOR]

This study explores the influence of blade design on the low-pressure extrusion process, which is relevant to techniques like spheronization. We investigate how blade geometry affects the extruded paste and final product properties. A model paste was extruded through a basket extruder with varying blade lengths to create distinct wedge gaps (20°, 26° and 32° contact angles). The theoretical analysis explored paste behavior within the gap and extrudate. A model material enabled objective comparison across blade shapes. Our findings reveal a significant impact of blade design on the pressure profile, directly influencing liquid distribution in the paste and extrudate. It also affects the required torque relative to extruder output. The findings of this study hold significant implications for continuous granulation, a technique employed in the pharmaceutical industry for producing granules with uniform size and properties. Understanding the influence of blade geometry on the extrusion process can lead to the development of optimized blade designs that enhance granulation efficiency, improve product quality, and reduce energy consumption. By tailoring blade geometry, manufacturers can achieve more consistent granule characteristics, minimize process variability, and ultimately produce pharmaceuticals with enhanced efficacy. [ABSTRACT FROM AUTHOR]

Regenerative dentistry has experienced remarkable advancement in recent years. The interdisciplinary discoveries in stem cell applications and scaffold design and fabrication, including novel techniques and biomaterials, have demonstrated immense potential in the field of tissue engineering and regenerative therapy. Scaffolds play a pivotal role in regenerative dentistry by facilitating tissue regeneration and restoring damaged or missing dental structures. These biocompatible and biomimetic structures serve as a temporary framework for cells to adhere, proliferate, and differentiate into functional tissues. This review provides a concise overview of the evolution of scaffold strategies in regenerative dentistry, along with a novel analysis (Bard v2.0 based on the Gemini neural network architecture) of the most commonly employed materials used for scaffold fabrication during the last 10 years. Additionally, it delves into bioprinting, stem cell colonization techniques and procedures, and outlines the prospects of regenerating a whole tooth in the future. Moreover, it discusses the optimal conditions for maximizing mesenchymal stem cell utilization and optimizing scaffold design and personalization through precise 3D bioprinting. This review highlights the recent advancements in scaffold development, particularly with the advent of 3D bioprinting technologies, and is based on a comprehensive literature search of the most influential recent publications in this field. [ABSTRACT FROM AUTHOR]

The world is moving towards decarbonization policies in the energy and industrial sectors to bring down carbon dioxide release and reach net zero emissions. Technologies to capture CO2 and use it as a feedstock to produce CO2-based chemicals and biofuels via chemical or biochemical conversion pathways can potentially reduce the amount of CO2 released. The paper serves the innovative scientific knowledge for CO2 transformation via a biochemical pathway to microalgal biomass with its subsequent treatment to biofuels and bioproducts assuming milder climatic conditions (Central or Eastern Europe, Visegrad countries or climatically related world regions). The recent trends were critically reviewed for microalgal biorefinery to reach the sustainability of microalgal-based chemicals with added value, digestion, hydrothermal liquefaction, pyrolysis, and gasification of microalgal residues. Knowledge-based chemical process engineering analysis, systematic data synthesis, and critical technical evaluation of available life cycle assessment studies evaluated the sustainability of microalgal biorefinery pathways. The research showed that biological CO2 fixation using water, seawater or wastewater to produce third-generation biomass is a promising alternative for bioethanol production via pretreatment, enzymatic hydrolysis, digestion, and distillation, and can be realized on a large scale in an economically viable and environmentally sound manner. Its best economically promising and sustainable pathway is perceived in producing microalgal-based nutraceuticals, bioactive medical products, and food products such as proteins, pigments, and vitamins. Machine learning methods for data mining, process control, process optimization, and geometrical configuration of reactors and bioreactors are the crucial research needs and challenges to implementing microalgal biorefinery in an operational environment. [ABSTRACT FROM AUTHOR]

Surface water and groundwater are polluted with pharmaceuticals, detergents, pesticides, and many other substances. Application of ferrates seems to be a perspective option for wastewater treatment as ferrates are not only powerful oxidizing agents but also an excellent disinfecting and coagulating agents decomposing many stable inorganic, organic, and biological compounds. Final products of their decomposition do not include carcinogenic or toxic products. In this paper, stability of electrochemically prepared potassium ferrate encapsulated in packaging materials printed on a 3D printer was monitored. In the experiment, electrochemically prepared potassium ferrate with different purity (21.4 %, 63.5 % and 67.3 %) was used. Stability of potassium ferrate was monitored for one month and that of other ferrates for three months. Different storage conditions of ferrate samples were also compared. Storage conditions had a significant influence on the ferrate stability. [ABSTRACT FROM AUTHOR]

The uniformity of pulp and the amount of rejects are influenced by many factors, but impregnation can be the most important. The opportunities for improving impregnation of kraft white liquor start in description of the parameters affecting the process. The first parameter is the chip itself (its basic density, moisture, and pH) and the second is the process parameters set by the technological possibilities of the digester. During outside storage, the chips deteriorate via the fungal stains, brittleness, and high acidity. The moisture content also decreases. Understanding the relationships of chip parameters in the impregnation step and amount of rejects requires the assignment of effective alkali consumption. This study shows the effects of selected physical parameters, such as bulk density, moisture, and pH, of spruce chips on alkali consumption during impregnation step of a Super Batch process. [ABSTRACT FROM AUTHOR]

Biomass products are used as an energy source in many fields of industry and households. One such source can be pellets or briquettes made of wood chips, ideally made of waste wood. The final quality of these products is affected by many parameters, not only the process (production) parameters but also the material properties are important. A common aim of the research is to maximize the calorific value and minimize the emission of greenhouse gases, which is mainly influenced by the particle size distribution of the raw material. A mixture containing very fine grains will not allow the flow of oxygen, which will make it more difficult to burn the briquette, and conversely, if the percentage of the coarse fraction is high, there will be a larger proportion of oxygen, causing a greater emission of contaminating gases. In addition, particle size distribution may also affect the production of briquettes and pellets, and therefore such analysis is necessary before the wood chips are processed. In the case of wood chips, the irregular--flaky shape is not the most ideal in terms of analysis. During the measurement, there is an effort to characterize each particle with one dimension. There are many ways to achieve this one dimension, while the result of each method of analysis may be different. For this reason, it is necessary to conduct a series of experiments on several devices to evaluate these measurements and compare the results. The first device used is Malvern's Mastersizer 3000, which uses the laser diffraction technique to measure the particle size. The second device used is Malvern's Morphologi G3, which measures the size and shape of the particle by static image analysis. The third usable device is Microtrac's PartAn 3D, which uses the dynamic image analysis method. The sieve analysis with the Retsch AS200 is employed to compare the results by laser and optical methods. [ABSTRACT FROM AUTHOR]

The article deals with the various methods of characterization and evaluation of the shape and dimensions of particles that are a product of grinding the beech chips in a knife mill. The speed of rotor with knives and two types of die were tested parameters. The product that was obtained by grinding has non-isometric particles. The main problem how to evaluate the particle size distribution for such materials is the choice of the characteristic size and the method for determining the particle size distribution. At present it is possible to use the modern, optical dynamic methods, based on particle visualization. The results from the both milling methods are processed into the various graphical dependencies, taking into account the shape of the particles and the particle size distribution. However, the particle size distribution also has an effect on the flow properties of the bulk materials. A special rheometer for measuring the flow properties of powders is used. The results of measurements are used for characterization the influence of the grinding process parameters on the flow properties of the product. [ABSTRACT FROM AUTHOR]

This work deals with the creation of a mathematical model which will predict with sufficient accuracy the size of granules in the high-shear granulation process. The aim of the paper was to create a model created with dimensionless criteria to give the size of granules as a function of selected process parameters, equipment, and experimental material. Microcrystalline cellulose granules were manufactured in an experimental granulator of our own construction using a high amount of granulation liquid (absolute humidity >40%). The work also focuses on the study of granule size distribution and the yield of the process in achieving the target granule fraction (0.4–3 mm). Particle size and particle size measurement were performed using 3 D dynamic image analysis (PartAn 3 D, Microtrac). The granules were analyzed with respect to their shape and width of distribution. Using the created model, it is possible with high probability, 89.4%, to predict on our device the median value of the granule size of microcrystalline cellulose, with ±0.1 mm precision. [ABSTRACT FROM AUTHOR]

The quasi‐static confined uniaxial compaction of granular alumina and boron carbide was studied, and the effect of triaxial stress on the materials as a function of increasing particle size was observed. The average particle sizes studied for granular alumina were 170 ± 63, 230 ± 55, 330 ± 67, and 450 ± 83 µm. The average particle size studied for granular boron carbide were 170 ± 40, 190 ± 34, 320 ± 59, and 470 ± 90 µm. The material response at hydrostatic pressure as a function of porosity, the bulk modulus as a function of hydrostatic pressure, and the transmission ratio as a function of applied load was evaluated for increasing particle size. For alumina, the increase in particle size resulted in an increase in strength for a fixed porosity, the bulk modulus of this material did not show clear particle size‐dependent trends, and the transmission ratio increased with increase in particle size. Conversely, for granular boron carbide, the hydrostatic pressure‐porosity curve shifted to the right with increasing particle size, the change in bulk modulus increased with increasing particle size, and no clear particle size‐dependent trends were observed when looking at the transmission ratio during the experiment. Post‐experiment scanning electron microscopy revealed that alumina powder fragmented from elongated shapes to block‐like structures, while boron carbide powder appeared more circular before the experiments and fragmented into smaller comminuted pieces. This paper discusses the implication of the work in the context of the limited experimental data in the field and the modeling of granular advanced ceramics behavior. [ABSTRACT FROM AUTHOR]

The newly developed gas chromatography-tandem mass spectrometry method allows the analysis of non-volatile, polar substances in cigarette ash. Only a few mg of ash, derivatized by two-step silanization with hexamethyldisilazane and N, O-bis(trimethylsilyl)trifluoroacetamide, are necessary for the analysis. Samples are directly analyzed after derivatization, without the need of extraction as a next purification step. Differences in chromatographic profiles reflect the composition uniqueness of each matrix and can be used for product authentication by chromatographic fingerprint method. The method was used to differentiate between cigarette ash samples of three cigarette brands (Marlboro, Davidoff, and West) and can be useful for forensic purposes. Graphical abstract: [ABSTRACT FROM AUTHOR]

Calcium carbonate in the form of finely ground limestone is a material that has found its application in a wide range of industries, in the chemical, rubber, agricultural, and paper industries, is used for desulfurization of boilers and other. In civil engineering, ground limestone is used for the production of building materials, plaster and mortar mixtures, as a filler in concrete mixtures, in road construction, and as an essential component of mastic asphalt. This paper deals with examining the modification of the properties of finely ground limestone by the tumbling agglomeration method. It has been shown that the components of concrete with a round grain have a positive effect on the pumping of concrete in comparison with an elongated grain or the rough surface of crushed stone. The experiments will be carried out on a granulation plate using a variety of granulation liquid. The agglomerates and their properties were compared with untreated finely ground limestone, with a focus on detecting changes in compressibility, density and particle size. The output of this paper is a description and graphical representation of the changes in the properties of ground limestone before and after the agglomeration process. [ABSTRACT FROM AUTHOR]

For the correct design of a fluid bed granulator whose output may be granules with the required form and properties, it is necessary to know the process parameters, such as the amount and type of binder, the flow parameters, air distribution and the rate of rotation of the disc. This paper deals with the detection of the kinetics of growth of the granules, specifically their distribution characteristics depending on the binder concentration in the liquid phase. The experiments will be carried out in a fluidized bed granulator with a rotating disc, which was designed at the Institute of Chemical and Hydraulic Machines and Equipment's at the Faculty of Mechanical Engineering of the Slovak University of Technology in Bratislava. The output of the experiments will be the determination of the distribution characteristics of the resulting final granulate. [ABSTRACT FROM AUTHOR]

Nowadays tabletting of powders in the pharmaceutical industry is, among other agglomeration processes, most widely used method of finalizing solid products. From a procedural point of view, stress fields of the tablet have the dominant importance because they directly determine its quality. This paper focuses on the experimental detection of the primary stresses during the compression of the pharmaceutical powdered substance AVICELL. Measurements will be performed on the KISTLER programmable electromechanical press in a die with a circular cross-section. Evaluation of the obtained data of the stress fields will be carried out by means of Mohr's circle. [ABSTRACT FROM AUTHOR]

Selective adjustment of the properties of particular material agglomeration has its inherent place in the chemical, food, but especially in the pharmaceutical, industry. The requirement to produce an agglomerate with desired particle size at a given strength is often formulated. To create the targeted product, it is necessary to know the process parameters affecting the preparation of its features. This paper deals with survey distribution characteristics and compressibility changes of an agglomerate in dependence on the duration of the granulation process through the usage of the most modern devices working with particulate materials. The investigated product will be prepared for coating granulating disc designed at the Institute of Process Engineering, Faculty of Mechanical Engineering, Slovak University of Technology in Bratislava. [ABSTRACT FROM AUTHOR]

The paper is focused on an analysis of the most frequently used compaction equations for powdered materials such as Heckel equation, Kawakita equation and Cooper-Eaton equation. Compacting powdered materials is accompanied by various mechanisms of densification dependent on the properties of the compressed material, which makes the equation more satisfactory for a certain group of materials and for another groups less so, or makes the equation completely unsuitable. To determine the suitability of the equation experimental measurements have to be implemented on an instrumented laboratory press. Then these obtained data are approximated by the specific compaction equation and use the regression analysis to determine the parameters describing the required material or physical properties of the compressed material. [ABSTRACT FROM AUTHOR]

To assess the energy intensity of particulate materials mixing, it is necessary to know the state of stress in the particulate material in front of mixing elements. The theoretical background of this process results from the theory of the equilibrium limit of the particulate material, and this state may by described by Mohr's circle theory and the Novosad model. Based on the above assumptions, it is possible to derive the pressure distribution along the blade height, but only for an infinitely long blade. A measuring system implemented on the homogenizer blade was constructed to examine the effects of the distribution of the mixed material on the mixing element along its length. [ABSTRACT FROM AUTHOR]

The aim of the work was to analyze the influence of process parameters of high shear granulation on the process yield and on the morphology of granules on the basis of dynamic image analysis. The amount of added granulation liquid had a significant effect on all monitored granulometric parameters and caused significant changes in the yield of the process. In regard of the shape, the most spherical granules with the smoothest surface were formed at a liquid to solid ratio of ≈1. The smallest granules were formed at an impeller speed of 700 rpm, but the granules formed at 500 rpm showed both the most desirable shape and the highest process yield. Variation in the shape factors relied not only on the process parameters, but also on the area equivalent diameter of the individual granules in the batch. A linear relationship was found between the amount of granulation liquid and the compressibility of the granules. Using response surface methodology, models for predicting the size of granules and process yield related to the amount of added liquid and the impeller speed were generated, on the basis of which the size of granules and yield can be determined with great accuracy. [ABSTRACT FROM AUTHOR]