Scale-independent solid fraction prediction in dry granulation process using a gray-box model integrating machine learning model and Johanson model.

A novel gray-box model is proposed to estimate molten steel temperature in a continuous casting process at a steel making plant by combining a first-principle model and a statistical model. The first-principle model was developed on the basis of computational fluid dynamics (CFD) simulations to simplify the model and to improve estimation accuracy. Since the derived first-principle model was not able to estimate the molten steel temperature in the tundish with sufficient accuracy, statistical models were developed to estimate the estimation errors of the first-principle model through partial least squares (PLS) and random forest (RF). As a result of comparing the three models, i.e., the first-principle model, the PLS-based gray-box model, and the RF-based gray-box model, the RF-based gray-box model achieved the best estimation performance. Thus, the molten steel temperature in the tundish can be estimated with accuracy by adding estimates of the first-principle model and those of the statistical RF model. The proposed gray-box model was applied to the real process data and the results demonstrated its advantage over other models.

Prediction of roller compacted ribbon solid fraction for quality by design development

We present a calibrated model to scale-up a roller compaction process using minimal experimental data at small scales. The compression properties of three API-laden blends are evaluated for various drug loadings using a laboratory-scale roller compaction simulator (Int J Pharm 269:403-15, 2004). Using the generated blend compression properties, a calibrated model combining the Reynolds roller compaction model (Comput Chem Eng 34:1049-57 2010) and ribbon solid fraction measurements is developed to predict the ribbon solid fraction as a function of the roller compaction conditions (roll force and roll gap). The predictions of this model are compared with measurements from ribbons generated on the Gerteis minipactor at various scales using appropriate methods. The predicted solid fractions achieve good agreement with measured solid fractions for the three drug products. Further, the calibrated model is extended by developing a parametrized regression model where several API properties, formulation properties, and ribbon solid fraction predictions from the Reynolds model are taken as features to generate ribbon solid fractions for partially characterized active blends. The predictions of the hybrid model agree reasonably with measurements on ribbons produced on a Gerteis 3-W-Polygran. This hybrid model can then be deployed to run digital Design of Experiments (DOEs), which is then used to define operating ranges for the roller compaction of two drug products. This method enables the application of digital tools to aid the scale-up of fast-moving drug product processes using minimal experimental data.

Elastic recovery in roll compaction simulation.

Roll compaction of maize powder

The importance of roller compaction is recently increasing. This study evaluates the combined effects of formulation factors, process parameters, and selected quality attributes on drug release from roller-compacted hypromellose-based matrix tablets containing carvedilol as a model drug. The influence of selected factors was statistically assessed and good predictive models were developed for various time points of the release profile. The results show that the release profile is mostly affected by the particle size distribution of granules and roll speed. This indicates that the roller compaction process has a major impact on drug release, which is also formulation dependent. A higher d50 and lower d90 value of spatial filtering technique-based particle size distribution results, a lower roll speed, increased hypromellose content, using microcrystalline cellulose as a filler, and higher tablet hardness, resulted in a decrease in the drug release rate. On the other hand, the effect of the roll pressure, size of screen apertures, and d10 values on drug release was insignificant. The significance of the factors was further explained by granule shape, their porosity, and friability evaluation, and by compressibility and compactibility studies of compression mixtures. Additionally, the spatial filtering technique demonstrated to be a promising tool in controlling the roller compaction process.

Elastic recovery (ER) has been investigated and discussed extensively in the field of tableting. However, until now only limited data is available regarding ER in roll compaction. Therefore, a previously established in-line measurement technique was rolled out to further investigate the kinetics of ER in roll compaction and the effects of specific compaction force (SCF) and roll speed (RS). In-line laser triangulation measurements at different positions within a roll rotation as well as measurement over time after the process has been stopped were utilized. Pure microcrystalline cellulose (MCC) and two placebo powder blend formulations were analysed. Successful fit of the contained ER profiles emphasized that the ER on the roll surface is build out of two exponential kinetics. Starting with a dominating fast ER (ERA), characterized by a high increase of the ribbon thickness after passing the gap width, followed by a slower ER (ERB). Sigma minus plot analysis showed that increasing RS led to an accelerated ERA and ERB which was related to the viscoelastic behaviour of MCC. The SCF only had an effect on the kinetics of ER if a brittle filler was added to the mixture. The conducted study established the first approach in literature to characterize the kinetics of ER in roll compaction. It supports the understanding and characterization of relaxation times and the effect of the RS and SCF in roll compaction.

Gray-Box Model to Control Molten Steel Temperature in Tundish

Gray-box model-based predictive control of Czochralski process

A simple method has been developed to estimate solid fraction or relative density of compacts using the weight of ribbons produced during roller compaction. The method provides an alternative to the commonly used dimensional measurement, especially for formulations not amenable to forming quality ribbons. Surface texture of the compaction rolls has been taken into consideration in our mathematical treatment along with correction for ribbon relaxation. Ribbon relaxation occurring upon ribbon exiting the compaction zone is estimated using roll geometry, roll gap, and ribbon thickness. Detailed experimental runs have been carried out to confirm the validity of the proposed theory. The predicted solid fraction was found comparable to that from actual dimensional measurement by caliper. In the case of the microcrystalline cellulose/dicalcium phosphate one:one formulation, the predicted solid fraction had an error sum of squares (SSE) of 2.64E-03 when compared to the dimensional method. When relaxation was included, the SSE decreased by four folds. Similarly, for the microcrystalline cellulose/lactose monohydrate 2:1 formulation, the SSE decreased twelfth folds when relaxation was taken into consideration. These results further confirm the utility of the proposed throughput method for estimating the solid fraction of ribbons.

A quality by design approach to investigate the effect of mannitol and dicalcium phosphate qualities on roll compaction

An evaluation of the Johanson model for roller compaction process development for a high dose API

Relationship between powder properties and uniformity of ribbon property using feeding guider designs with thermography (PAT) in roller compaction

The effect of compaction method on steel fiber reinforced concrete pavement (SFRC) has been simulated in this study, a locally manufactured steel roller compactor is designed to simulate steel roller compactor which is commonly used in site for compaction. 0.8 % volume fraction (\( V_{f} \)) of steel fiber content is used and compacted using roller compactor in three cases category, case 1: load 10 kg and no. of cycles are 8, 16, 24 cycles. Case 2: initial stage: load 10 kg and no. of cycles are 4, 8, 12 cycles and finial stage: load 25 kg and no. of cycles are 4, 8, 12 and finally Case 3: load 25 kg and no. of cycles are 8, 16, 24 cycles. The obtained beam specimens were tested using a locally manufactured impact load apparatus and test results has been compared with steel fiber reinforced concrete beam specimens compacted using conventional compaction method. Test results show that the optimum steel fiber roller compacted concrete beam specimen under impact load test gives 17 blows for first crack and 173 blows for failure while steel fiber reinforced concrete beam specimen compacted using conventional method gives 15 blows for first crack and 110 blows for failure. Material properties have also been improved when using roller compactor by about 9.74%, 8.84% and 4.76% for compression strength, tensile strength and modulus of elasticity respectively.

Purpose. Investigation of the composition, structure and properties of powder materials obtained by electrodispersion of tungsten waste of the VA brand in an oxygen–containing medium - distilled water. Methods. To determine the composition, structure and properties of powder materials, samples of powders obtained from waste tungsten of the VA brand were studied. The powder material was obtained by electroerosive dispersion in distilled water. Microanalysis of powder particles was carried out using a scanning electron microscope, analysis of the size distribution of powder particles was obtained using a particle size analyzer, X-ray spectral microanalysis of powder particles was carried out using an energy dispersive X-ray analyzer integrated into a scanning electron microscope, analysis of the phase composition of powder particles was carried out using X-ray diffraction on a diffractometer. Results. During the study, it was revealed that the shape of the particles obtained from powdered tungsten materials is spherical and elliptical, and agglomerates of smaller particles are also marked on magnification. Oxygen and tungsten are present in the composition of powder materials, while there are no joint structural components. The phases of pure tungsten in α and β modifications are noted in the phase composition. It follows from the analysis of the granulometric histogram that the particle size spread varies in the range of 0.092–62.59 microns, while the average particle diameterwas 5.73 microns. Conclusion. The obtained research results can be used to develop a new heavy pseudo-alloy using metal waste of expensive raw materials by the method of electroerosive dispersion with subsequent improvement and optimization of the composition and structure of the alloy.