Search Results (35)

In vitro hedging; combined with the fed-batch liquid media process is an innovative system that generates multiple sterile plants without the use of exogenous cytokinin. This combined process was demonstrated with Cannabis sativa (‘Cherry1’, ‘BaOx’, ‘T1’, ‘Peach’) grown in vessels of three different physical states—stationary agar (A); stationary Oasis^® infused with liquid (OILs); and agitated Oasis^® infused with liquid (OILa). Vessels were pre-selected as control or supplemented; where supplement vessels received 15 mL DKW liquid media each cycle harvest. The number of shoot tips harvested; shoot length; and dry shoot mass from repeated cutting cycles was recorded. In a single harvest; ‘BaOx’ and ‘Cherry 1’ produced one shoot per plant from the original 15 planted on all treatments. ‘Peach’ and ‘T1’ produced less shoots on average; but the most in OIL treatments. All shoots harvested were longer in OIL compared to A; regardless of genotype. Over multiple cycles; ‘Peach’ and ‘T1’ were unable to reliably produce shoots on a repeated schedule and were, therefore, eliminated from the experiment. By cycle 3; maximum number of plants were produced; regardless of supplementation (‘Cherry 1’; 30; ‘BaOx’; 22). Shoot length was above 10 mm (planting standard) for both genotypes until after the third cycle (10 weeks) where number and quality decreased (nodes and internodes easily discerned). By the end of the experiment; the only shoots that remained productive for over 16 weeks and multiple repeated harvest cycles were those in OIL treatments with supplements. Full article

A better understanding of mixing times for mixed solvent systems in laboratory-scale vessels is crucial for improving mixing-sensitive processes such as antisolvent crystallisation. Whilst mixing in agitated vessels has been extensively studied using solutions of additives in the same solvent, there is very limited literature on the mixing of different miscible solvents and none which would be relevant to antisolvent crystallisation processes. In this work, the mixing times of water–ethanol systems in a 1 litre vessel, agitated by a pitched blade impeller with probes used as baffles, were investigated in the transitional flow regime using both experimental and computational fluid dynamics (CFD) approaches. We studied two scenarios: adding sodium chloride tracer to premixed water–ethanol solutions and adding ethanol containing a tracer to water. Mixing was investigated experimentally through conductivity measurements and computationally using large eddy simulations with the M-Star CFD software package. Empirical correlations from the Dynochem engineering toolbox were also used for comparison. The results showed significant run-to-run variability in the mixing times from both experiments and CFD simulations, with experimental ranges being notably wider than CFD ones under the given conditions. While the CFD simulations showed consistent mixing times across different solvent compositions, the experimental mixing times decreased with increasing ethanol content. The mixing times were approximately inversely proportional to the impeller speed. The CFD simulations indicated that 25–40 impeller rotations were required for homogenisation, while the experiments needed 25–100 rotations. The Dynochem correlations predicted 40 rotations, independent of speed, but could not capture the inherent variability of the mixing times. Full article

An original design of a simple bioreactor was used to fabricate two tubular, 200 cm long BC structures by culturing Komagataeibacter sucrofermentans B-11267 on a molasses medium. In addition, a tubular BC-based biocomposite with improved mechanical properties was obtained by combining cultivation on the molasses medium with in situ chemical modification by polyvinyl alcohol (PVA). Moreover, the present study investigated the BC production by the K. sucrofermentans B-11267 strain on the media with different molasses concentrations under agitated culture conditions. The dynamics of sugar consumption during the cultivation were studied by HPLC. The structure and physicochemical properties of BC and tubular BC structures were characterized by FTIR spectroscopy and X-ray diffraction (XRD). Thus, the findings indicate that K. sucrofermentans B-11267, when cultivated in a molasses medium, which is such a cheap waste product in the sugar industry, forms a significant amount of BC with a high crystallinity degree. The BC tubular structures demonstrated great potential for their application in biomedicine as artificial blood vessels and conduits for nerve regeneration. Full article

In industrial mixing processes, impeller design, rotational speed, and mixing conditions play a crucial role in determining process efficiency, product quality, and energy consumption. Optimizing the performance of stirring systems for non-Newtonian fluids is essential for achieving better results. This study examines the hydrodynamic and thermal performance of stirring systems for viscoplastic fluids, utilizing close-clearance anchor impellers with chamfered angles of 22.5°, 45°, and 67.5° in cylindrical, flat-bottom and unbaffled vessels. Through a comprehensive comparative analysis between standard and chamfered impeller designs, the study evaluates their efficacy in overcoming yield stress, enhancing flow dynamics, and improving thermal homogeneity. The effects of Reynolds number and yield stress on the hydrodynamic and thermal states are analyzed. The results indicate that the 67.5° chamfered impeller significantly improves flow distribution and minimizes dead zones, particularly in critical areas between the anchor blades and vessel walls, where mixing stagnation typically occurs. It also enhances vertical mixing by promoting a broader shear spread along the vessel height and a more uniform temperature distribution. These insights contribute to the development of more efficient agitation systems, applicable across various industries handling complex fluids. Full article

In this paper, a heat generator with fluid agitation is developed and experimentally studied. This heat generator can convert kinetic energy from a wind turbine directly to thermal energy through the process of viscous dissipation—a process achieved through the agitation of the working fluid inside a container. In the experimental study, an electric motor (instead of a wind turbine) was used to provide the kinetic energy input to the heat generator. The torque, rotational speed, and temperature rise in the fluid were measured. Using the measured quantities, the efficiency of kinetic energy to sensible heat conversion was calculated. Experiments were conducted to investigate the effects of different impellers, rotational speeds, and working fluids, including distilled water, ethylene glycol (EG), and their respective nanofluids, with ${\mathrm{A}\mathrm{l}}_2{\mathrm{O}}_3$ nanoparticles at different concentrations. The study also found that the temperature rise in fluids due to viscous dissipation was influenced by the specific heat of the fluid, suggesting that the heat generator can be optimized for energy storage with high-specific-heat fluids, such as water, or for achieving a higher temperature rise with low-specific-heat fluids, such as ethylene glycol. The experimental results indicated that the heat generator was up to 90% efficient in converting kinetic energy to thermal energy. The study revealed that, for constant power input, the heat dissipation rate depends solely on the vessel’s geometry, not the fluid properties. Optimizing the impeller design and baffles within the vessel is crucial for maximizing power input. For applications, a wind turbine can power this heat generator to provide heat to a house or a commercial building. Full article

The increasing demand for sustainable energy sources has intensified the exploration of biogas power plants as a viable option. In this research, we present a novel approach that leverages machine learning techniques to optimize the performance of biogas power plants through the strategic placement and configuration of rotors within the fermentation vessel. Our study involves the simulation of a diverse range of biogas power plant scenarios, each characterized by varying rotor locations and rotating speeds, influencing the agitation levels of the biogas substrate. The simulation results, encompassing multiple performance metrics, serve as input data for an artificial neural network (ANN). This ANN is trained to learn the intricate relationships between rotor placement, rotor speed, agitation levels, and overall system efficiency. The trained model demonstrates predictive capabilities, enabling the estimation of plant efficiency based on specific rotor configurations. The proposed methodology provides a tool for both optimizing existing biogas power plants and guiding engineers in the design and setup of new facilities. Our model aims to offer valuable insights for engineers in the initial planning stages of new biogas power plants, enabling them to make informed decisions that contribute to sustainable and efficient energy generation. Full article

This study aims to optimize the frying process of natural porous materials (like potatoes) by enhancing heat and mass transfer phenomena through significant horizontal acceleration values following a spatially periodic pattern that alternates the intensity of inertia forces uniformly across the frying vessel. The generated horizontal inertial forces act complementary to the normal vertical buoyancy force for the creation of agitating convective currents in the oil and for vapor bubbles’ departure from the surface of frying objects. The use of an innovative frying device, employing simultaneous rotation around two vertical axes at a different speed in a so-called planetary type of motion, serves to facilitate this production of horizontal acceleration values that allows intensifying the performance of frying. The present investigation examines the impact of rotational speed, along with oil temperature and frying duration, on the water loss and sensory evaluation of fried items. The potato-to-oil ratios typically found in industrial frying operations are employed. The intended outcome is a more energy-efficient frying process, reduced cooking times, and a healthier product due to lower frying temperatures and the consequent decreased formation of harmful compounds. This approach carries substantial implications for food processing, potentially enhancing productivity while limiting operational costs. Full article

The present work investigates a comparative study between mechanical and Imhoflot^TM cells on a mini-pilot scale and the applicability of one self-aspirated H-16 cell (hybrid Imhoflot^TM cell) on an industrial scale on-site. The VM-04 cell (vertical feed to the separator vessel with 400 mm diameter) was fabricated, developed, and examined. The copper flotation experiments were conducted under similar volumetric conditions for both the Imhoflot^TM and mechanical flotation cells keeping the rest of the parameters constant. Further, one H-16 cell was positioned at four different stages in the Gökirmak copper flotation circuit of the Acacia (Türkiye) copper beneficiation plant, i.e., at (i) pre-rougher flotation, (ii) rougher concentrate, (iii) cleaner-scavenger tailing, and (iv) first cleaning concentrate aiming at enhancing the flotation circuit capacity through flash flotation in the rougher stage, reducing copper grade in the final tailing, and increasing cleaning throughput, respectively. Comparative copper flotation tests showed that ultimate recoveries using the Imhoflot^TM and mechanically agitated conventional cells were 94% and 74%, respectively. The industrial scale test results indicated that locating one pneumatic H-16 cell with the duty of pre-floating (also known as flash flotation) led to the enrichment ratio and recovery of 4.84 and 89%, respectively. Positioning the H-16 cell at the cleaner-scavenger tailings could diminish the copper tailings grade from 0.43% to 0.31%. Further, a relatively greater enrichment ratio and copper recovery were obtained using only one Imhoflot^TM cell (1.76 and 64%) in comparison with employing four existing mechanical cells (50 m³, each cell) in series (1.45 and 60%) at the first cleaner stage. Full article

The world’s oceans and seas host >100 known strains of thraustochytrids, a common group of marine eukaryotic unicellular protists, residing in diverse marine habitats, with many others to be isolated and cultivated. The thraustochytrids have become of considerable industrial interest due to health benefits gained from their high percentages of valuable bioactive compounds, revealing the needs for the isolation of new potential strains. Employing a recently developed isolation methodology (use of cell culture medium), we assess initial culture conditions and growth paces of newly isolated thraustochytrid cells (thraustochytrid sp. BSH), originated from the colonial tunicate Botryllus schlosseri, residing on Helgoland Island, Germany. Cells were cultivated under static versus agitated conditions, along with two inoculation sizes (0.5 × 10⁶ and 1 × 10⁶ cells/dish) and in three vessel types (35 mm Petri dishes and T25 and T75 flasks; containing 3, 5 and 15 mL medium, respectively). Cultures were observed under regular microscopy, confocal microscopy and H&E staining. While cells in all conditions grew fast, results revealed the superiority of agitated cultivation in T75 flasks inoculated with 0.5 × 10⁶ cells/dish (6.41 ± 1.91-fold increase/week). Further, 18S rDNA revealed high similarities (99.5–99.8) of strain BSH to two thraustochytrid strains from Monterey, California (USA), B. schlosseri colonies, elucidating a new understanding of these animals-protists associations. Full article

Emulsions containing crystalline dispersed phases hold significant importance in pharmaceutical, chemical, and life science industries. The industrial agitation and storage of these emulsions can prompt crystallization effects within the flow field, intersecting with the primary nucleation mechanisms. Notably, contact-mediated nucleation, in which subcooled droplets crystallize upon contact with a crystalline particle, and shear-induced crystallization due to droplet deformation, are both conceivable phenomena. This study delves into the crystallization processes of emulsions in a 1 L stirred vessel, integrating an ultrasonic probe to monitor droplet crystallization progression. By scrutinizing the influence of the flow field and of the emulsifiers stabilizing the droplets, our investigation unveils the direct impact of enhanced rotational speed on accelerating the crystallization rate, correlating with increased energy input. Furthermore, the concentration of emulsifiers is observed to positively affect the crystallization process. Significantly, this pioneering investigation marks the first evaluation of emulsion crystallization considering the overlapping nucleation mechanisms seen in industrial production of melt emulsions. The findings offer valuable insights for more systematic control strategies in emulsion crystallization processes, promising more efficient and sustainable industrial practices by enabling targeted application of shear and surfactants. Full article

Technological advancements have continued to progress in all fields, achieving remarkable feats. Additionally, productivity is increasing across the board as a result of strong economic expansion, which has encouraged changes in people’s way of life, such as the increasing use of pharmaceutical products, cosmetics, detergents, and food products. A hydrothermal study is required in these areas to optimize the design of the stirring system. The aim of the current work is to investigate the hydrodynamics and thermodynamics of a mechanical agitation system with a non-Newtonian fluid of the Bingham–Bercovier type in a cylindrical vessel with three blade configurations. Our research is specifically directed towards mechanically agitated systems utilizing close clearance stirrers, particularly focusing on the anchor, gate and two-bladed impellers, within cylindrical tanks that possess flat bottoms without baffles. The results show that the anchor impeller, with its broad blades and low-shear characteristics, is more suited for breaking down yield stress and inducing flow in these fluids, which creates a wide flow pattern that effectively overcomes yield stress. However, the addition of vertical arms to transform it into a gate impeller promotes mixing, heat transfer and thermal efficiency with a small energy cost compared to an anchor impeller against the two-bladed impeller. Full article

Dendrobium loddigesii has long been used in traditional folk medicine. The purpose of this study was to optimize the culture conditions for its protocorm-like bodies (PLBs) and explore their biological activities. The use of an air-lift bioreactor demonstrated superior PLB proliferation compared to agitated and solid culture methods. The optimal inoculum quantity of 30 g/vessel, cultured for 28 days in the bioreactor, yielded the highest PLB biomass production. Analysis of PLB extracts revealed that the ethyl acetate (EtOAc) extract exhibited the highest levels of flavonoids and alkaloids, as well as potent antioxidant activity demonstrated by DPPH free radical scavenging assay and reducing power. Furthermore, the antiproliferative effects of the PLB extracts were assessed using MTT assays, and the EtOAc extract showed significant efficacy by reducing cell viability by over 60% in the human colon carcinoma cell line SW620 at the highest tested concentration (200 μg/mL). Mechanistic analysis revealed the downregulation of key regulatory apoptosis genes, including survivin, p53, caspase-3, and caspase-9. These results demonstrate the potential of the bioreactor culture method for the efficient production of D. loddigesii PLBs and the biological activities of the EtOAc extract, suggesting its therapeutic potential. Full article

The performance of gas-liquid mixing processes in agitated vessels is commonly measured by the degree of gas dispersion, and local measurements of this parameter can provide a more accurate description of the mixing, especially for non-Newtonian fluids. For instance, the fluid flow of complex yield-pseudoplastic solutions is highly affected by the local shear stress, leading to a non-homogeneous air distribution throughout the mixing vessel. Coaxial mixers have demonstrated energy-efficient characteristics for non-Newtonian fluids that improve mixing homogeneity due to the independent rotation of a central impeller and a close-clearance impeller. Therefore, this work aims to investigate the axial profile of the local gas holdup in a PBT-anchor coaxial mixer containing xanthan gum solutions, which is a biopolymer widely utilized as an emulsion stabilizer, dispersing agent, and thickener. The rheological behavior of the solutions was described by the Herschel-Bulkley model, and the effect of the xanthan gum concentration on the gas holdup distribution was analyzed. Electrical resistance tomography (ERT) was employed to obtain the gas holdup from the conductivity measurements of the mixture in each of the four horizontal planes. Results show that the gas holdup increased downward for all solutions, and a lower xanthan gum concentration reduced the non-homogeneity in gas distribution and the overall gas volume fraction. In contrast, higher xanthan gum concentrations enhanced gas holdup in high shear stress regions while weakening air dispersion distant from those regions due to higher viscous forces. Full article

The size of container vessels is continuously growing, always exceeding expectations. Port authorities and terminals need to constantly adapt and face challenges related to maritime infrastructure, equipment, and operations, as these are the principal areas affected by the future Ultra Large Container Vessels (ULCVs). Maneuvring areas are at their limits, and mooring equipment is at an increased risk of being overloaded. This study aims to analyze the limitations that present mooring systems may face when ULCVs are subjected to wind and passing-ship forces exerted by a future ULCV and wind forces through Dynamic Mooring Analysis (DMA). A hypothetical and massive future ULCV with a capacity of 40,000 TEU is compared to the Emma Maersk, which is a present vessel that regularly calls at container terminals. The Emma Maersk, with its current mooring arrangement, experiences higher motion than future ULCVs, which experience higher forces but are also moored with more and stronger lines. This translates into considerably higher loads in the mooring system, potentially compromising safe mooring conditions at the terminal. Mitigating measures are proposed in the study to face these limitations. In addition, the study explores the potential of new and innovative mooring technologies, such as high-strength synthetic ropes and smart mooring systems, to address the challenges posed by ULCVs. A container terminal at the Port of Rotterdam, Europe’s largest sea port, has been analyzed as a case study. The terminal is located next to a busy fairway that leads to other container terminals, justifying the need to analyze both wind and passing-ship effects on moored ships. Full article

Emulsions with crystalline dispersed phase fractions are becoming increasingly important in the pharmaceutical, chemical, and life science industries. They can be produced by using two-stage melt emulsification processes. The completeness of the crystallization step is of particular importance as it influences the properties, quality, and shelf life of the products. Subcooled, liquid droplets in agitated vessels may contact an already crystallized particle, leading to so-called contact-mediated nucleation (CMN). Energetically, CMN is a more favorable mechanism than spontaneous nucleation. The CMN happens regularly because melt emulsions are stirred during production and storage. It is assumed that three main factors influence the efficiency of CNM, those being collision frequency, contact time, and contact force. Not all contacts lead to successful nucleation of the liquid droplet, therefore, we used microfluidic experiments with inline measurements of the differential pressure to investigate the minimum contact force needed for successful nucleation. Numerical simulations were performed to support the experimental data obtained. We were able to show that the minimum contact force needed for CMN increases with increasing surfactant concentration in the aqueous phase. Full article