Particle tracking in a lab-scale conical fluidized bed dryer

Conical fluidized bed dryers are widely used in the pharmaceutical industry due to their high heat and mass transfer characteristics. Despite their widespread use, very little is known about the hydrodynamics of conical fluidized bed dryers. Wet pharmaceutical granule has high moisture content and wide particle size distribution (PSD), which can lead to poor mixing and non uniform drying. Uneven moisture content in the final product can adversely affect the quality and shelf life of these high value drugs. Previous studies on the conical fluidized bed dryers focused on the study of the gas phase, however motion of particulate phase has never been studied. Particle tracking is an important tool to study the motion of the particulate phase. Two particle tracking techniques were developed and used to study the motion of the particulate phase in a conical fluidized bed dryer. The first technique was radioactive particle tracking (RPT) which was developed at the University of Saskatchewan laboratory for a vessel having conical geometry. Experiments were conducted using dry pharmaceutical granule and during the actual drying of wet pharmaceutical granule. Two radioactive tracers of different sizes (1.6 to 2.6 mm) were tracked in each set of experiments to determine the effect of particle size on particle motion and particle mixing. Superficial gas velocities of 1, 1.5, 2 and 2.5m/s were used in dry bed studies to quantify the effect of superficial gas velocity. The second particle tracking technique was developed at the labs of Merck Frosst Canada Inc. Movies were captured using a high speed video camera coupled to a borescope and then analyzed off-line using image analysis software.Three powders having mean particle diameters of 774, 468 and 200 microns were used. Experiments were conducted at superficial gas velocities of 1.5, 2 and 3 m/s. RPT revealed that there is a distinct circulation pattern of the particulate phase. Particles move upwards at high velocities near the centre of the bed and fall slowly near the walls. Furthermore, most of the gas flow is concentrated near the centre of the bed and the circulation pattern was observed at all the superficial gas velocities. Particle size of the tracer particle and PSD of the bed material had an appreciable impact on particle mixing with bigger particles exhibiting higher segregation tendencies than the smaller ones in the case of dry granule having a broad PSD. Particle segregation due to size difference was more pronounced at a superficial gas velocity of 1 m/s. However, segregation decreased with an increase in superficial gas velocity. During drying of wet granule, particle mixing and motion of the tracer particle was poor during the first 7 minutes of drying suggesting that most of the gas flow was concentrated near the centre of the bed. Particle mixing and average particle speeds increased considerably when the moisture content in the granule was less than 18 wt% suggesting a change in the hydrodynamics of the bed with the gas being more evenly distributed throughout the bed. Image analysis of high speed movies also suggested that a dilute region existed at the center of the bed. These observations were in agreement with the observations made by RPT

New frontiers in international strategy

This paper is based on a panel we organized at the "First Annual Conference on Emerging Research Frontiers in International Business Studies", organized by the Journal of International Business Studies (JIBS), to discuss several new lines of research in international strategy. Four lines of research are developed: The strategic implications of semiglobalization, the impact of institutional voids in international strategy, primitives and levels of analysis in international business, and strategies for the base of the pyramid. Taken together, these studies aim to open a new frontier in our understanding of International Strategy, based on the co-location of firms as places and a key element in international business.international business; semiglobalization; internal strategy; base pyramid; institutions; competitiveness;

Real-Time Global Illumination for VR Applications

Real-time global illumination in VR systems enhances scene realism by incorporating soft shadows, reflections of objects in the scene, and color bleeding. The Virtual Light Field (VLF) method enables real-time global illumination rendering in VR. The VLF has been integrated with the Extreme VR system for realtime GPU-based rendering in a Cave Automatic Virtual Environment

Attention-Based UNet Deep Learning Model for Plaque Segmentation in Carotid Ultrasound for Stroke Risk Stratification: An Artificial Intelligence Paradigm

Stroke and cardiovascular diseases (CVD) significantly affect the world population. The early detection of such events may prevent the burden of death and costly surgery. Conventional methods are neither automated nor clinically accurate. Artificial Intelligence-based methods of automatically detecting and predicting the severity of CVD and stroke in their early stages are of prime importance. This study proposes an attention-channel-based UNet deep learning (DL) model that identifies the carotid plaques in the internal carotid artery (ICA) and common carotid artery (CCA) images. Our experiments consist of 970 ICA images from the UK, 379 CCA images from diabetic Japanese patients, and 300 CCA images from post-menopausal women from Hong Kong. We combined both CCA images to form an integrated database of 679 images. A rotation transformation technique was applied to 679 CCA images, doubling the database for the experiments. The cross-validation K5 (80% training: 20% testing) protocol was applied for accuracy determination. The results of the Attention-UNet model are benchmarked against UNet, UNet++, and UNet3P models. Visual plaque segmentation showed improvement in the Attention-UNet results compared to the other three models. The correlation coefficient (CC) value for Attention-UNet is 0.96, compared to 0.93, 0.96, and 0.92 for UNet, UNet++, and UNet3P models. Similarly, the AUC value for Attention-UNet is 0.97, compared to 0.964, 0.966, and 0.965 for other models. Conclusively, the Attention-UNet model is beneficial in segmenting very bright and fuzzy plaque images that are hard to diagnose using other methods. Further, we present a multi-ethnic, multi-center, racial bias-free study of stroke risk assessment

Planned Marketing Adaptation and Multinationals' Choices Between Acquisitions and Greenfields

International marketing studies have extensively examined the antecedents of firms' marketing standardization/ adaptation decisions. However, it is unclear whether such decisions, once planned, codetermine the choice between buying and building foreign subsidiaries. Analyzing a sample of 150 foreign entries by Dutch firms, the authors find that the level of marketing adaptation planned for a wholly owned subsidiary is positively related to the likelihood that the subsidiary will be established through an acquisition rather than through a greenfield investment. Moreover, the authors find substantial evidence that this positive relationship is stronger for firms that (1) are establishing relatively larger subsidiaries, (2) have less experience with the industry entered, or (3) are entering less developed countries. The findings show that firms pursuing higher levels of marketing adaptation assign more value to the marketing adaptation advantages of acquisitions over greenfields, especially if the risks associated with implementing the planned adaptation level are high. In addition, firms typically strive for a fit between their international marketing strategy and their mode of foreign establishment. (authors' abstract

A complete 3D numerical study of the effects of pseudoscalar-photon mixing on quasar polarizations

We present the results of three-dimensional simulations of quasar polarizations in the presence of pseudoscalar-photon mixing in the intergalactic medium. The intergalactic magnetic field is assumed to be uncorrelated in wave vector space but correlated in real space. Such a field may be obtained if its origin is primordial. Furthermore we assume that the quasars, located at cosmological distances, have negligible initial polarization. In the presence of pseudoscalar-photon mixing we show, through a direct comparison with observations, that this may explain the observed large scale alignments in quasar polarizations within the framework of big bang cosmology. We find that the simulation results give a reasonably good fit to the observed data.Comment: 15 pages, 8 figures, significant changes, to appear in EPJ

Estimating global injuries morbidity and mortality : methods and data used in the Global Burden of Disease 2017 study

Background: While there is a long history of measuring death and disability from injuries, modern research methods must account for the wide spectrum of disability that can occur in an injury, and must provide estimates with sufficient demographic, geographical and temporal detail to be useful for policy makers. The Global Burden of Disease (GBD) 2017 study used methods to provide highly detailed estimates of global injury burden that meet these criteria. Methods: In this study, we report and discuss the methods used in GBD 2017 for injury morbidity and mortality burden estimation. In summary, these methods included estimating cause-specific mortality for every cause of injury, and then estimating incidence for every cause of injury. Non-fatal disability for each cause is then calculated based on the probabilities of suffering from different types of bodily injury experienced. Results: GBD 2017 produced morbidity and mortality estimates for 38 causes of injury. Estimates were produced in terms of incidence, prevalence, years lived with disability, cause-specific mortality, years of life lost and disability-adjusted life-years for a 28-year period for 22 age groups, 195 countries and both sexes. Conclusions: GBD 2017 demonstrated a complex and sophisticated series of analytical steps using the largest known database of morbidity and mortality data on injuries. GBD 2017 results should be used to help inform injury prevention policy making and resource allocation. We also identify important avenues for improving injury burden estimation in the future

Global injury morbidity and mortality from 1990 to 2017 : results from the Global Burden of Disease Study 2017

Correction:Background Past research in population health trends has shown that injuries form a substantial burden of population health loss. Regular updates to injury burden assessments are critical. We report Global Burden of Disease (GBD) 2017 Study estimates on morbidity and mortality for all injuries. Methods We reviewed results for injuries from the GBD 2017 study. GBD 2017 measured injury-specific mortality and years of life lost (YLLs) using the Cause of Death Ensemble model. To measure non-fatal injuries, GBD 2017 modelled injury-specific incidence and converted this to prevalence and years lived with disability (YLDs). YLLs and YLDs were summed to calculate disability-adjusted life years (DALYs). Findings In 1990, there were 4 260 493 (4 085 700 to 4 396 138) injury deaths, which increased to 4 484 722 (4 332 010 to 4 585 554) deaths in 2017, while age-standardised mortality decreased from 1079 (1073 to 1086) to 738 (730 to 745) per 100 000. In 1990, there were 354 064 302 (95% uncertainty interval: 338 174 876 to 371 610 802) new cases of injury globally, which increased to 520 710 288 (493 430 247 to 547 988 635) new cases in 2017. During this time, age-standardised incidence decreased non-significantly from 6824 (6534 to 7147) to 6763 (6412 to 7118) per 100 000. Between 1990 and 2017, age-standardised DALYs decreased from 4947 (4655 to 5233) per 100 000 to 3267 (3058 to 3505). Interpretation Injuries are an important cause of health loss globally, though mortality has declined between 1990 and 2017. Future research in injury burden should focus on prevention in high-burden populations, improving data collection and ensuring access to medical care.Peer reviewe