The Effect of Design and Size of the Fluid-Bed Equipment on the Particle Size-Dependent Trend of Particle Coating Thickness and Drug Prolonged-Release Profile.

The focus of the current work is to study and demonstrate the impact of the design, the scale, and settings of fluid-bed coating equipment on the differences in pellet coating thickness, which in case of prolonged-release pellets dictates the drug release. In the first set of coating experiments, the pellet cores were coated with the Tartrazine dye with the aim of estimating the coating equipment performance in terms of coating thickness distribution, assessed through color hue. In the second set, drug-layered pellets were film-coated with prolonged-release coating and dissolution profile tests were performed to estimate the thickness and uniformity of the coating thickness among differently sized pellets. In both study parts, film coating was performed at the laboratory and the pilot scale and essentially two types of distribution plate and different height adjustments of the draft tube were compared. The dye coating study proved to be extremely useful, as the results enable process correction and the optimal use of the process equipment in combination with the appropriate process parameters. Preferential film coating of larger drug-containing pellets was confirmed on the laboratory scale, while on the pilot scale, it was possible to achieve preferential coating of smaller pellets using rational alternatives of settings, which is desirable in terms of particle size-independent drug release profile of such prolonged-release dosage forms.

Towards Tomography-Based Real-Time Control of Multiphase Flows: A Proof of Concept in Inline Fluid Separation.

The performance of multiphase flow processes is often determined by the distribution of phases inside the equipment. However, controllers in the field are typically implemented based on flow variables, which are simpler to measure, but indirectly connected to performance (e.g., pressure). Tomography has been used in the study of the distribution of phases of multiphase flows for decades, but only recently, the temporal resolution of the technique was sufficient for real-time reconstructions of the flow. Due to the strong connection between the performance and distribution of phases, it is expected that the introduction of tomography to the real-time control of multiphase flows will lead to substantial improvements in the system performance in relation to the current controllers in the field. This paper uses a gas-liquid inline swirl separator to analyze the possibilities and limitations of tomography-based real-time control of multiphase flow processes. Experiments were performed in the separator using a wire-mesh sensor (WMS) and a high-speed camera to show that multiphase flows have two components in their dynamics: one intrinsic to its nonlinear physics, occurring independent of external process disturbances, and one due to process disturbances (e.g., changes in the flow rates of the installation). Moreover, it is shown that the intrinsic dynamics propagate from upstream to inside the separator and can be used in predictive and feedforward control strategies. In addition to the WMS experiments, a proportional-integral feedback controller based on electrical resistance tomography (ERT) was implemented in the separator, with successful results in relation to the control of the distribution of phases and impact on the performance of the process: the capture of gas was increased from 76% to 93% of the total gas with the tomography-based controller. The results obtained with the inline swirl separator are extended in the perspective of the tomography-based control of quasi-1D multiphase flows.

Analysis of Pressure Fluctuation Characteristics of Central Swirl Combustors Based on Empirical Mode Decomposition.

In order to study the characteristics of pressure fluctuation during unstable combustion, experimental studies had been conducted on the mechanism model of the swirl combustor and the industrial swirl combustor. The signal of dynamic pressure, heat release rate, and the high-speed flame image in the two combustors were synchronously collected by using dynamic pressure sensors, a photoelectric sensor, and a high-speed camera under normal temperature and pressure. After empirical mode decomposition of the dynamic pressure signal, several intrinsic mode functions were obtained. It was found that the pressure pulsation energy is concentrated in the first three order intrinsic mode function. Through fast Fourier transform spectrum calculation, it was found that the first three order intrinsic mode function pulsation can characterize the changes of heat release rate and air flow pulsation under cold state and flame instability. It showed that the decomposition of the dynamic pressure in the combustor by this method can obtain the main physical processes in its connotation, and provide data processing methods for the induction mechanism of oscillating combustion and combustion diagnosis in an industrial combustor test.

A Fast Electrical Resistivity-Based Algorithm to Measure and Visualize Two-Phase Swirling Flows.

Electrical resistance tomography (ERT) has been used in the literature to monitor the gas-liquid separation. However, the image reconstruction algorithms used in the studies take a considerable amount of time to generate the tomograms, which is far above the time scales of the flow inside the inline separator and, as a consequence, the technique is not fast enough to capture all the relevant dynamics of the process, vital for control applications. This article proposes a new strategy based on the physics behind the measurement and simple logics to monitor the separation with a high temporal resolution by minimizing both the amount of data and the calculations required to reconstruct one frame of the flow. To demonstrate its potential, the electronics of an ERT system are used together with a high-speed camera to measure the flow inside an inline swirl separator. For the 16-electrode system used in this study, only 12 measurements are required to reconstruct the whole flow distribution with the proposed algorithm, 10× less than the minimum number of measurements of ERT (120). In terms of computational effort, the technique was shown to be 1000× faster than solving the inverse problem non-iteratively via the Gauss-Newton approach, one of the computationally cheapest techniques available. Therefore, this novel algorithm has the potential to achieve measurement speeds in the order of 104 times the ERT speed in the context of inline swirl separation, pointing to flow measurements at around 10kHz while keeping the average estimation error below 6 mm in the worst-case scenario.

An Improved Shape from Focus Method for Measurement of Three-Dimensional Features of Fuel Nozzles.

The precise three-dimensional measurement of fuel nozzles is of great significance to assess the manufacturing accuracy and improve the spray and atomization performance. This paper proposes an improved fast shape from focus (SFF) method for three-dimensional measurement of key features of fuel nozzles. In order to ensure the measurement accuracy and efficiency of the SFF, the dispersion of the measured points from a standard flat plane was used to select the optimal combination of the focus measure operator, window size and sampling step size. In addition, an approximate method for the focus measure interval is proposed to improve the measurement efficiency, which uses the peak region of the central pixel to replace the peak region of other pixels. The results show that the proposed method decreased the average computation time of the focus measure by 79.19% for the cone section and by 38.30% for the swirl slot. Compared with a reference laser scanning microscope, the measurement error in length is within 10 µm and the error in angle is within a maximum 0.15°.

Enhanced oil removal from oily sand by injecting micro-macrobubbles in swirl elution.

Environmental contamination by petroleum hydrocarbons was exacerbated by oil pipeline breaks, marine oil spills and discharges from industrial production. To further improve the removal performance of petroleum hydrocarbons in solid particles, the deoiling experiments of swirl elution with micro-macrobubbles on oily sands were carried out in this paper. Experiment results indicated that when particles fell from the center of the bubble, the collision efficiency was 99.3%. The instantaneous contact angle (ICA) between the macrobubbles and the oil layer was improved in the presence of microbubbles. Furthermore, the maximum ICA of bubbles attaching to the oil layer was found to occur at pH 9 in the system of oily sand mixtures ranging from pH 5 to pH 14. This finding indicated that the slightly alkaline solution was more advantageous for bubbles to attach to the oil layer than the highly alkaline solution. The optimum condition for the elution of oily sand in the mixture of pH 7-14 was pH 12, and the oil removal efficiency was 85.4% for 10 min. The oil removal efficiency of swirl elution (SE) with bubbles on oily sand at pH 12 for 10 min was superior to either SE without bubbles or air flotation (AF). The results show that the swirl elution with bubbles can effectively enhance the oil removal efficiency of oily sands and provide guidance for controlling the environmental petroleum hydrocarbon contamination and reducing the usage of surfactants.

Cooperative physical separation of oil and suspended solids from methanol-to-olefin wastewater: A pilot study.

Methanol-to-olefin (MTO) is an important non-petroleum chemical process for the preparation of light olefins. However, the MTO process consumes copious amounts of water and produces large amounts of untreated effluent. Therefore, the realization of efficient wastewater treatment and recycling is key to the green low-carbon development of MTO. Here, a cooperative process combining swirl regenerating micro-channel separation (SRMS) and combined fibrous coalescence (CFC) technologies was proposed to separate high contents of oil and suspended matter in MTO wastewater. Using a pilot device with a treatment capacity of 1 m3/h, the average oil content in MTO wastewater decreased from 750 mg/L to <30 mg/L, while the average content of suspended matter decreased from 108 mg/L to <15 mg/L. Compared with a commercial MTO wastewater treatment process (olefin production capacity of 0.6 million tons per annum), the proposed method could reduce wastewater discharges and costs by 57% and US$ 0.23 million per annum respectively. Equipment costs and operational energy consumption were also reduced by 30% and >95% respectively. The combined process may provide the basis for the green and sustainable treatment of MTO wastewater and its recycling.

Numerical Simulation of Swirl Flow Characteristics of CO2 Hydrate Slurry by Short Twisted Band.

The development of oil and gas resources is gradually transferring to the deep sea, and the hydrate plugging of submarine pipelines at high pressures and low temperatures is becoming an important problem to ensure the safety of pipeline operations. The swirl flow is a new method to expand the boundary of hydrate safe flow. Numerical simulation of the hydrate slurry flow characteristics in a horizontal pipeline by twisted band has been carried out, and the flow of CO2 hydrate slurry in low concentration has been simulated by the RSM and DPM models. The results show that the heat transfer efficiency is also related to Re and particle concentration. The velocity distribution has the form of symmetrical double peaks, and the peaks finally merge at the center of the pipeline. Vortexes firstly appear on both sides of the edge of the twisted band, and then move to the middle part of the twisted band. Finally, the vortex center almost coincides with the velocity center. The rotation direction of hydrate particles is the same as the twisted direction of the twisted band, twist rate (Y) is smaller, Re is larger, and the symmetric vortex lines merge farther away. The initial swirl number is mainly related to Y, but not Re. The swirl flow attenuates exponentially, and its attenuation rate is mainly related to Re, but not Y. Compared with ordinary pipelines, the swirl flow can obviously improve the transportation distance of hydrate slurry.

Use of Bedside Ultrasonography and Saline Flush Technique for Evaluation of Central Venous Catheter Placement in Children.

Our study investigated the reliability of appearance of rapid atrial swirl flow (RASF) by ultrasonography (US) in the right atrium (RA), which occurred as a result of rapid isotonic saline infusion (RISI) into the central venous catheter (CVC), in predicting catheter tip position. This prospective observational study included 95 CVC procedures performed on 77 pediatric patients (41 boys and 36 girls) with a median age of 0.6 (0.29-1.53) years. Seventy-three (76.84%) catheter tips were found to be correctly placed, and 22 (23.15%) catheter tips were misplaced. While ultrasonographic examination revealed RASF in the RA after 93 catheterization procedures, it was not observed after two catheterization procedures. One of these two catheters was an arterial catheter, and the other was a catheter that was directed toward the subclavian vein after curling around itself. There was no significant difference between the groups with incorrect and correct positioned catheter tip in terms of the appearance of RASF by US after RISI. There was no significant difference between the groups with upward (n = 8) and downward (n = 86) positioned catheter tip in terms of the time until the first appearance of RASF after RISI and the phase of RASF (P > 0.05). There was a significant difference between these two groups in terms of the disappearance time of RASF in the RA (P < 0.001). The mean disappearance time of RASF was 3 (2-3) s for downward positioned catheters and 5 (4-7) s for upward positioned catheters, respectively. When the cut-off for the disappearance time of RASF was set to 3 s, US had a sensitivity of 85.71% and a specificity of 77.91% for detecting upward positioned catheters. In conclusion, the appearance of RASF in the RA in a short time by US is not a reliable finding for correct positioning of the CVC tip in the pediatric patient group. The fact that the disappearance time of RASF in the RA is longer than 3 s indicates upward positioned CVCs. These catheters must never be used without radiological confirmation. In CVCs in which the disappearance time of RASF in the RA is shorter than 3 s, we think that the catheter can be used until radiological confirmation in emergency cases. According to the available literature, our study is the first study in children. There is a need for new studies on this subject.

Swirl sign in traumatic acute epidural hematoma: prognostic value and surgical management.

The swirl sign is identified as a small area of low attenuation within an intracranial hyperattenuating clot on non-enhanced computed tomography (CT) scans of the brain, which represents active bleeding. The purpose of this study was to evaluate the incidence of the swirl sign among patients with acute epidural hematoma (AEDH) and to identify its prognostic value and impact on surgical treatment. A retrospective review was performed of patients with a diagnosis of traumatic EDH by CT scan who were surgically treated at the Department of Neurosurgery of the First People's Hospital of Jingmen between January 2010 and January 2014. Patients with combined or open craniocerebral injuries and those who did not undergo surgical treatment were excluded. Of the 147 patients evaluated, 21 (14%) exhibited the swirl sign on non-enhanced CT scans of the brain. Univariate analysis revealed a significant correlation between the occurrence of the swirl sign and preoperative Glasgow coma scale scores, preoperative mydriasis, time from injury to CT scan, and intraoperative hematoma volume. Compared with patients without this sign, those exhibiting the swirl sign had a higher mortality rate (24 vs. 6%, respectively; P = 0.028) and a worse outcome (Glasgow Outcome Scale score ≤ 3: 38 vs. 15%, respectively; P = 0.027) at 3 months. An adjusted analysis showed that the occurrence of the swirl sign was an independent predictor of poor outcome (death: odds ratio (OR) = 4.61; 95% confidence interval (CI): 1.34-15.82; P < 0.05; 3-month Glasgow Outcome Scale score ≤ 3: OR = 3.47; 95% CI: 1.27-9.49; P < 0.05). In conclusion, the occurrence of the swirl sign on the head CT scan of patients with AEDH was found to be significantly associated with poor outcome. Therefore, early identification of this sign and aggressive management with early surgical evacuation is crucial for improving patient outcome.