Cohesive powders are troublesome in terms of flow reliability, consistency and accuracy, posing great challenges in manufacturing. In this article the current understanding of rheological behaviour of powders, considering bulk friction and apparent shear viscosity, is reviewed. Flow rules accounting for particle properties, process dynamics, and their interactions have been proposed in literature, but require rigorous experimental validation. The suitability of state-of-the-art instruments for this purpose is critically reviewed. The current understanding of the influence of particle properties, fluid drag and shear strain rate on the dynamics of powder flow is summarised, including the topical subject of powder spreadability for additive manufacturing.
The recent pandemic of COVID-19 brings the topic of vaccines and the urgency with which they are required into the popular literature. This article focuses on the merits of using nanovaccines to establish mucosal immunity in the respiratory tract the primary site of infection and transmission for a variety of infectious diseases. Targeting the innate immune response which is mediated by airway macrophages, the host cell for some pathogens, can be achieved with a variety of nanoparticle technologies conferring protection from the disease.
The article reviewed the solid collection performance and scale-up methodology of gas-solid cyclones at high solid density conditions based on experimental and numerical studies mainly published after 2007. The models to predict pressure drop of cyclone, the non-uniform distribution of gas-solids flow, and scale-up methodology, the phase graph of the stability of uniform distribution/maldistribution of solids in parallel cyclones, and recent progress in high-solid loading cyclones are summarized.
With increasing quantity of waste generated and fast growing concerns about climate change, there has been renewed impetus recently to develop advanced thermochemical processes using waste biomass as a feedstock. This is because these processes have the potential to add value to cheap and abundant materials by converting them into advanced biofuels and chemicals. This reviews paper is concerned principally with newest applications of fluidised bed reactors for waste treatment, with particular attention given to those processes aimed at the production of clean syngas for the subsequent synthesis of high-value products, including bio-hydrogen, synthetic natural gas, and liquid fuels.
Understanding particle properties and powder behavior during handling and processing requires the characterization of the inner-core and surface properties. Most routine characterization methods involve the former. However, the dynamic behavior of large collections of particles, even if they are much larger than the nanoparticle scale, are dominated by their surface energy at the bulk (square meter, not microscopic) level. Bulk-surface energy of powder blends can differentiate between uniform mixing and the system’s inability to reach mixing equilibrium. Single-particle microscopic characterization techniques, while excellent complement to bulk-level methods, are not ideal for assessing surface energy in connection to properties like powder flow. However, microscopic techniques are invaluable in predicting some bulk-level properties of powders, such as the specific type of surface exposed when powders are subjected to processes such as milling.
Microorganisms are ubiquitous in the Earth’s biosphere. Majority of them poses a threat for humans, being either naturally occurring or artificially introduced into the air and forming bioaerosols. Bringing together the contemporary status of information in the area, this ‘eye-opening’ article characterizes in condensed form the environmental sources of microbial aerosols, their role in atmospheric processes, provides their physical and biological characteristics which result in adverse health effects, discusses analytical techniques used for their quantitative and qualitative evaluation, presents methods for establishing standards of exposure, and comments on their usefulness in the control and protection of environment and health.
Supercritical hydrothermal synthesis is a promising methodology of nanoparticle fabrication. This review introduces principles of the process as well as the characteristics of the products synthesized by the method. The process design of the supercritical method, surface control by organic modification, and the possible application of the nanohybrid materials are focused on.
Despite the facts that the applied particle concentration and the field of usages are completely different, air filter and bag filter are regarded as similar because of at the point of using fine fibers as dust collecting body. The article reviewed the collection performance of a single fiber collection efficiency at different mechanisms and time changes of collection performance of both filters is reviewed precisely based on numerous previous studies.
Inhaled dry powder therapeutics occupy a growing sector in the pharmaceutical market and meet demands unmet by alternative formulation counterparts. The dry powder inhaler offers the benefits of short delivery times, ease of administration, increased bioavailability, and excellent shelf-life. However, dry powder therapeutics have not transitioned to the market at the same rate as alternative pulmonary delivery platforms. This article addresses some of the barriers to the success of dry powder therapeutics from the preclinical stage to the market. The article concludes with a discussion on improvements needed to address current research model failures and identifies barriers to dry powder formulation and development.
Droplet microfluidics is a novel discipline of science dealing with generation, manipulation and creative use of emulsions - fluidic equivalent of granular matter. In this work Authors provide a comprehensive introduction to droplet microfluidics. The review covers fundamentals and presents some of the most important applications of the emulsions - representative to the broad interest in droplet microfluidics ranging from material science, through biomedical experiments and diagnostics, to applications in pharmaceutical, food, and cosmetic industries.
As Discrete Element Modelling (DEM) increases its utilization as tool for the simulation of particulate materials in a variety of processing unit operations, there is a continuous focus on develop robust methodologies for model calibration to guarantee reliable predictive results. This paper focus on providing insights on advantages and limitations on typical approaches for calibration and validation. The calibration process using a series of small scale tests was then validated experimentally and numerically utilizing independent application tests.
The preparation of nano/micromotor systems has been a hot topic in nanotechnology and biotechnology for the last decade. This review explains the underlying physics of the nano/micromotors, which is completely different from that of conventional macroscale motors. Additionally, the authors introduce various types of nano/micromotors, especially chemical reaction propelled motors.
Widely used in the minerals, cement, ceramics and chemical industries for 150 years, ball mills have attracted the attention of engineers in describing size reduction quantitatively for over 70 years. However, this last quarter of a century has been particularly active, given the widespread use of the discrete element method, which has triggered the development of novel modeling approaches to describe size reduction in them. The work reviews the various hurdles that have been faced by researchers and the solutions proposed to overcome them in describing size reduction in ball mills using the so-called advanced models, with emphasis on the work by the author and his co-workers at the University of Rio de Janeiro.
Novel concepts for solar cells to increase the energy conversion efficiency have proven very promising over the last decade or so. However, implementation of such light management designs have not reached commercial products. Bottom up fabrication with nanoparticles, especially from gas aggregation nanoparticle source, are the most likely path to industrial realisation. In this review paper we present a wide range of possibilities to use such nanoparticles to increase the efficiency of solar cells, both as light management and constituent.
The present study address the challenges with modeling the fluidization of ground biological materials which are typically non-spherical in shape, and have widely varying sizes. The Ergun equation that is commonly used to model particle fluidization was modified to incorporate non-uniformity sizes, shape factor, and the high void ratio that are typically present in ground biological materials. The results of the study will address the challenges in using models to scale up, size, and design equipment reactors for fluidizing biomass and other biological materials.
Recent progresses in laser ablation technology enables to generate various kind of nanoparticles with unique functionalities and superior performance. This review discusses the formation mechanism and techniques for synthesizing the functional nanostructures such as size-controlled semiconductor quantum dots, carbon nanotubes, nanowires, and core shell nanoparticles.
The present study through batch kinetic experiments with the use of quartz as test material aims to assess the effect of ball filling volume on the specific rate of breakage and identify the cumulative breakage function by keeping the powder filling volume constant. A new methodology is proposed by combining two software packages for the reliable description of the grinding process that enables the scale-up of laboratory results to larger scale mills.
In the continually growing realm of therapeutic siRNA research, inhaled delivery of siRNA has been an attention-grabbing route of administration due to its potential as a targeted approach for protein synthesis inhibition through RNA interference. Evident hurdles to effective siRNA delivery include overcoming the natural defenses of the lungs as well as intracellular internalization and release of siRNA. This valuable article discusses different preparation methods for multiple types of nanoparticulate delivery systems of siRNA that have been composed of lipids, polymers, peptides, and inorganic materials. Additionally, the authors discuss examples of these cutting-edge nanoparticle siRNA delivery systems to the lungs via various inhalation delivery devices.