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Mixed electronic and ionic conductivity (MIEC) perovskite oxides hold promise as cathode with high oxygen reduction reaction (ORR) activity for solid oxide fuel cells (SOFCs) operating at reduced temperatures. However, these MIEC cathodes usually contain lanthanide or alkaline-earth elements at A-site. These elements tend to interact with yttria-stabilized zirconia electrolyte (YSZ) to form unwanted phases such as La2Zr2O7 and SrZrO3 at conventional electrode fabrication conditions (>800 °C). Such unwanted interfacial reaction severely degrades the cell performance. We present a new method to assemble SrCo0.4Fe0.5W0.1O3-δ (SCFW) directly onto YSZ by a highly efficient microwave plasma technique. Intimate contact between SCFW and YSZ phases can be achieved by ten-minute microwave-plasma treatment with no new phase formation. Consequently, the microwave-plasma fabricated interface exhibits a notably high ORR performance, showing an area-specific resistances of 0.11 Ω cm2 at 600 °C, about two orders of magnitude better than the equivalent prepared via the conventional method. Our method is also effective in assembling other MIEC perovskite cathodes such as SrCo0.5Fe0.5O3-δ and SrCo0.8Nb0.1Ta0.1O3-δ on YSZ electrolyte, achieving notable enhancement of the cathode performance. This study thus provides an effective and convenient method for synthesizing reactive and robust interfaces between two incompatible phases with minimized interphase interactions.

A mechanistic model for tumbling mills was developed based on breakage characteristics and tumbling mill operational features. The concept was presented at the IMPC (International Mineral Processing Congress) 2014, followed by progress in a sub-process of the model presented at the IMPC 2016. Additionally, a number of papers on the sub-models and breakage function have been published. This paper provides a consolidated summary of the outcomes and status of the model. The overall model structure is presented along with the sub-models such as appearance functions, breakage rate functions, energy distribution, transport, and dual component grinding interaction model. The strengths and capabilities of the model structure as achieved to date are presented. The approach developed can be used as a platform for building multicomponent models. The modelling work can be done quicker by using an existing structure such as the one presented in this paper. It is recommended that researchers assess compatibility prior to embarking on model development work if the intention is to use this model structure.

Granule breakage is an important rate process in wet granulation that promotes product uniformity and controls product size and strength. In this work, a model to predict granule breakage is proposed and experimentally validated. The model assumes exponential of the surviving granules, dependent on a probability of breakage; a function of powder and binder properties, as well as operating parameters. Validation experiments were performed with a breakage-only granulator, filled with cohesive, non-granulating sand. Premade pellets made from lactose monohydrate and silicone oils were granulated at several impeller speeds, and the number of survivors was observed over time. The results revealed that the number of granules did indeed decay exponentially. It was found that the overall probability of breakage was inversely proportional to the capillary number. Moreover, the pore saturation played an important role in determining the probability of breakage, with higher pore saturations reducing breakage overall. A comparison with experimental data from literature revealed that the developed models agrees qualitatively with the experimental data, but is unable to fully capture the effect of powder properties and powder-binder interaction.

Scale-up of any engineering process is a great technical and economic challenge. Scale-up of granulation processes, in particular, is difficult and often problematic due to the inherently heterogenous nature of the materials used. However, recent improved understanding of the rate processes that control granulation improves our ability to do rational scale-up.

Single particle breakage characterisation at fine sizes for use in mill modelling has been addressed by only a few researchers and is not utilised in engineering design. This is mainly due to the challenge of accurately imparting a range of impact energies to sub-millimetre particles and then measuring the progeny size distribution for the tiny resultant mass. In order to fill this gap, a dispersed monolayer multi-particle breakage method was applied with a mini JK Drop weight tester in this work to extend the single particle breakage test from 16 mm down to 425 μm, covering a specific energy (Ecs) range of 0.1 - 2.5 kWh/t to provide a wide range of test conditions. A challenge that had to be addressed was switching from single particle to dispersed mono-layer due to the physical constraints of drop-height and drop mass in maintaining accuracy in input energy over the orders of magnitude required to apply the required specific range of energy input. As only a limited size range could be subjected to both single particle and mono-layer bed breakage, it was necessary to establish if the two testing techniques provide the same breakage results. A novel application of the Fréchet distance was successfully applied to quantitatively evaluate the discrepancy of progeny size distribution between single particle breakage and monolayer multiple particle breakage. Extrapolation of an empirical Fréchet distance model indicated that the application of dispersed mono-layer breakage below 2 mm provides an acceptable comparison with the single particle breakage applied to coarser sizes, thus facilitating the fitting of a single appearance function across this wide range of sizes and applied breakage energies.

The rapid rise in the health burden associated with chronic wounds is of great concern to policymakers, academia, and industry. This could be attributed to the devastating implications of this condition, and specifically, chronic wounds which have been linked to invasive microbial infections affecting patients’ quality of life. Unfortunately, antibiotics are not always helpful due to their poor penetration of bacterial biofilms and the emergence of antimicrobial resistance. Hence, there is an urgent need to explore antibiotics-free compounds/formulations with proven or potential antimicrobial, anti-inflammatory, antioxidant, and wound healing efficacy. The mechanism of antibiotics-free compounds is thought to include the disruption of the bacteria cell structure, preventing cell division, membrane porins, motility, and the formation of a biofilm. Furthermore, some of these compounds foster tissue regeneration by modulating growth factor expression. In this review article, the focus is placed on a number of non-antibiotic compounds possessing some of the aforementioned pharmacological and physiological activities. Specific interest is given to Aloevera, curcumin, cinnamaldehyde, polyhexanide, retinoids, ascorbate, tocochromanols, and chitosan. These compounds (when alone or in formulation with other biologically active molecules) could be a dependable alternative in the management or prevention of chronic wounds.

This work aims to build a generic dynamic model structure, which can accommodate interchangeable sub-models of each sub-process, making it amenable to continuous upgrade without the need for redevelopment, for multicomponent tumbling grinding mills. The Generic Tumbling Mill Model Structure (GTMMS) is based on a population mass balance framework which incorporates breakage characteristics, transport, classification along the mill, a discharge function, and energy consumption incorporated in a dynamic mill model structure. Version III builds on two earlier versions by incorporating energy distributions derived from discrete element modelling, an updated version of the 4D breakage appearance function which applies to a broader size range, and addresses multi-component ore breakage via the probability distribution of energy split based on material stiffness. The model has been tested against multi-component plant survey data. GTMMS III suggests a mechanistic insight into mixture prediction through component analysis and is a step forward towards the unified comminution model (UCM) with its mechanistic, generic, and dynamic prediction capability.

Background: The COVID-19 vaccine for children and adolescents, who are indispensable populations to curb the pandemic, would protect this population against rare severe COVID-19 and infectious conditions. Here we aimed to assess the safety, tolerability and immunogenicity of a candidate COVID-19 vaccine, CoronaVac, containing inactivated SARS-CoV-2, in children and adolescents aged 3-17 years old. Methods: We did a randomised, double-blind, placebo-controlled phase 1/2 clinical trial of CoronaVac in healthy children and adolescents aged 3-17 years old in Zanhuang (Hebei, China). Vaccine (in 0 ·5ml aluminum hydroxide adjuvant) or placebo (adjuvant only) was given by intramuscular injection in two doses (day 0 and day 28). We conducted phase 1 trial in 71 participants with an age de-escalation in tree groups and dose-escalation in two blocks (1.5ug or 3ug per injection). Within each block, participants were randomly assigned (3:1) using block randomisation to receive CoronaVac or placebo. In phase 2, participants were randomly assigned (2:2:1) using block randomisation to receive either CoronaVac at 1.5ug or 3ug per dose, or placebo. The primary safety endpoint was adverse reactions within 28 days after each injection in all participants who received at least one dose. The primary immunogenicity endpoint was seroconversion rate at 28 days after the second injection and its GMT as the secondary endpoint. This study is ongoing and is registered with ClinicalTrials.gov (NCT04551547). Findings: Between October 31 and December 2, 2020, 72 participants were enrolled in phase 1, and between December 12 and December 30, 2020, 480 participants were enrolled in phase 2. 500 participants received at least one dose of vaccine or placebo (n=71 for phase 1 and n=479 for phase 2; safety population). In the combined safety profile of phase 1 and phase 2, any adverse reactions within 28 days after injection occurred in 56 (26%) of 219 participants in the 1·5ug group, 63 (29%) of 217 in the 3ug group and 27 (24%) of 114 in the placebo group, without significant difference. Most adverse reactions were mild and moderate in severity and injection site pain (73[13%]) of 550 participants was the most frequently reported event. As of March 12, 2021, only one serious adverse event has been reported, which was considered unrelated to vaccination. In phase 1, seroconversion after the second dose was observed in 27 of 27 participants (100·0% [95%CI 87·3-100·0]) in the 1·5ug groups and 26 of 26 participants (100·0% [86·8-100·0]) in the 3ug group, with the geometric mean titers of 55·0 (95%CI 38·9-77·9) and 117·4 (87·8-157·0). In phase 2, seroconversion was seen in 180 of 186 participants (96·8% [93·1-98·8]) in the 1·5ug group and 180 of 180 participants (100·0% [98·0-100·0]) in the 3ug group, with the geometric mean titers of 86·4 (73·9-101·0) and 142·2 (124·7-162·1). There were no detectable antibody responses in the placebo groups. Interpretation: CoronaVac was well tolerated and induced strong neutralising antibody responses in children and adolescents aged 3-17 years. The study has provided solid safety and immunogenicity data to support the further study and use of CoronaVac in children and adolescents. Trial Registration: NCT04551547 Funding Statement: Chinese National Key Research and Development Program and Beijing Science and Technology Program. Declaration of Interests: QG and XL are employees of Sinovac Life Sciences Co., Ltd. YS, WY and LW are employees of Sinovac Biotech Ltd. All other authors declare no competing interests. Ethics Approval Statement: The clinical trial protocol and informed consent form were approved by the Ethics Committee of Hebei CDC (IRB2020-005).

Milling is commonly used for controlling the size distribution of granules in the pharmaceutical dry granulation process. A thorough understanding of the breakage of single compacts is crucial in unravelling the complex interactions that exist between different pharmaceutical feed materials and the mill process conditions. However, limited studies in the literature have examined the impact breakage of single pharmaceutical compacts. In this study, pharmaceutical powders including the microcrystalline MCC 101, MCC 102 and MCC DG were compressed at different pressures and tablets with different porosities and thicknesses were produced. Impact breakage tests were conducted in an air gun and the tablet impact velocities and breakage patterns were analysed using a Phantom ultrahigh-speed camera. It was observed that the tablet breakage rate and the amount of fines reduced as the tablet porosity decreased. In addition, thin tablets with low porosity exhibited semi-brittle fracture and less intense crack propagation while thick tablets with high porosity primarily disintegrated into fine fragments. Thus, this study provides a better understanding of the breakage behaviour of different pharmaceutical materials and can potentially be used to describe the breakage modes of compacts in the ribbon milling processes.

Dry granulation is commonly used in the pharmaceutical industry for compressing heat and moisture sensitive feed materials into compacts, subsequently followed by milling. Population balance models (PBMs) are often used to explore the effects of milling conditions on the granule size distribution (GSD) but limited studies have investigated the effects of the feed material and ribbon properties on the resulting GSD. In this work, a variety of feed materials and ribbons with different mechanical properties were used to validate a mass-based bi-modal breakage function developed in a previous study (Olaleye et al., 2019). Ribbon like tablets (referred to as ribblets) with a range of precisely controlled porosities were produced using an Instron machine and pharmaceutical excipients including the microcrystalline cellulose MCC 101, MCC DG and a DCPA/MCC mixture. Roll compacted ribbons were also produced using MCC 102 and MCC DG excipients. The ribblets and ribbons were milled in an impact-dominated cutting mill and PBM parameters were obtained from the ribblet milling data. Mechanistic models related to the feed ribbon property were then developed. It was found that the PBM with the mass-based bi-modal breakage function can accurately predict the GSDs of both the milled ribblets and roll compacted ribbons. The model developed was successfully linked to ribbon properties such as porosity for the first time and the model parameter a that reflects the fines mode in the bi-modal breakage function increased linearly with ribblet porosity. This work demonstrates the versatility of the developed PBM and provides a systematic approach for describing the ribbon milling process.

Dry granulation through roll compaction is a technology commonly used in the pharmaceutical industry for producing roll compacted ribbons. The significance of the feed screw speed and roll speed during ribbon production was highlighted in recent publications. However, previous studies focused primarily on the individual effects of either the feed screw speed or roll speed on ribbon porosity, and the synergetic effect of these parameters was rarely examined. The aim of this study therefore was to investigate the effects of the screw-to-roll speed ratio on the porosity of roll compacted ribbons, produced at different roll compaction conditions using the microcrystalline cellulose MCC, Avicel PH-102 feed material. It was observed that ribbon porosity decreased linearly with increasing screw-to-roll speed ratio. Furthermore, an increase in the speed ratio led to an increase in the roll gap and mass throughput while a decrease in the screw constant was observed. Thus, this study demonstrates that the screw-to-roll speed ratio can be treated as one of the critical process parameters for controlling ribbon porosity and can also be used to determine the optimum operating regimes during roll compaction.

Nanoemulsion-based formulations are finding increasing applications in cosmetics and personal care markets and come into widespread use due to a number of advantages they present. They are able to improve the physicochemical stability of cosmetic products due to the protection of labile groups from degradation (Kaul et al., 2018). Additionally, they offer controlled release of active compounds, assisting with lower toxicity and/or no irritation implications. Retinol (vitamin A), is a widely used antioxidant with antiaging properties that stimulates the production of collagen and elastin fibres (Ganceviciene et al., 2012). However, retinol is quite unstable and prone to oxidation and degradation, therefore encapsulation in a vehicle could play a crucial role in eliciting its efficacy. The vehicle has a major effect on the vitamin stability, transdermal delivery and bioavailability (Nastiti et al., 2017). Micelles, due to their small particle size (≤100nm) and high surface area, are considered promising candidates for transdermal delivery of actives. However, it is still not clear whether they can effectively penetrate the skin barrier. In this work, a retinol formulation developed by Phytoceutical Ltd was further characterised in terms of particle size and stability. Additionally, the penetration of the retinol formulation through a skin model that mimics the internal skin structure has been evaluated in vitro using Franz diffusion cells. Our findings show that the particle size of the retinol micelles is uniform and has a diameter of 20 nm. The formulation also presented long-term stability with a shelf life more than 18 months. The penetration studies revealed that a percentage of the applied retinol was able to penetrate and remain in the skin model and a very low percentage of the total retinol (

Possessing the advantages of both polymeric membranes and the specific inorganic nanoparticles or nanotubes, mixed matrix membranes (MMMs) have captured the imagination of researchers for a possible technological breakthrough for efficient gas separation. However, it is still very challenging to achieve defect-free interface between fillers and polymer matrix. In this study, the naturally abundant and low cost halloysite nanotubes (HNTs) were applied as fillers for MMMs synthesis. To improve the filler dispersion and filler-matrix interface affinity, the raw HNTs were modified by either alkali etching or (3-Aminopropyl) triethoxysilane grafting. After surface etching, the defect holes were formed on the surfaces of etched-HNTs, resulting in the rougher HNT walls and significant increment of surface area and CO2 adsorption capacity. The filler/polymer interfacial voids and filler dispersion were quantitatively assessed by tomographic focused ion beam scanning electron microscopy. HNTs surface etching significantly improved the HNTs/polymer interfacial affinity (void% = 0.06% for Raw-HNTs MMM, 0.02% for Etched HNTs MMMs) and filler dispersion, while grafted-HNTs mainly contribute to the filler dispersion. Compared to the pure polymer membrane and MMMs with untreated HNTs, MMMs containing 10 wt.% etched HNTs filler exhibited both increased CO2 permeability (807.7 Barrer) and higher CO2 selectivity (CO2/CH4 selectivity of 27.8) on the well-known limit of Robeson upper bound. In contrast, grafting HNTs only increased the membrane permeability without enhancing CO2 selectivity. The results suggest that surface etching can be an effective route in filler modification to improve interfacial morphology and membrane separation performance.

© 2018 Elsevier Inc. The increasingly uncertain dynamics of technological change pose special challenges to traditional technology forecasting tools, which facilitates future-oriented technology analysis (FTA) tools to support the policy processes in the fields of science, technology & innovation (ST&I) and the management of technology (MOT), rather than merely forecasting incremental advances via analyses of continuous trends. Dye-sensitized solar cells are a promising third-generation photovoltaic technology that can add functionality and lower costs to enhance the value proposition of solar power generation in the early years of the 21st century. Through a series of technological forecasting studies analyzing the R&D patterns and trends in Dye-sensitized solar cells technology over the past several years, we have come to realize that validating previous forecasts is useful for improving ST&I policy processes. Yet, rarely do we revisit forecasts or projections to ascertain how well they fared. Moreover, few studies pay much attention to assessing FTA techniques. In this paper, we compare recent technology activities with previous forecasts to reveal the influencing factors that led to differences between past predictions and actual performance. Beyond our main aim of checking accuracy, in this paper we also wish to gain some sense of how valid those studies were and whether they proved useful to others in some ways.

Pursuing efficient and low-cost catalysts for the sluggish oxygen evolution reaction (OER) is imperative for the large-scale deployment of promising electrochemical technologies such as water splitting and CO₂ electrochemical reduction. The earth-abundant perovskite catalysts based on LaNiO₃-δ show promise in OER catalysis because of their relatively low cost and their optimal electronic structure but suffer from low electrode-area normalized activity. In this work, we partially substituted La with Sr and Ni with Fe to enable a remarkably high OER activity with an ultra-low overpotential of 374 ± 3 mV vs RHE at a current density of 10 mA cm−2 normalized by electrode geometric area. This performance even surpasses the performance of benchmark RuO2. Our results show that Sr could promote OER-active sites including Ni(III), O2−₂/O−, and optimal Ni/Fe ratios, which significantly improve the surface intrinsic activity at the perovskite surface. Therefore, this work not only developed a highly efficient earth-abundant catalyst towards OER, but also demonstrated the effective modulation of catalyst surface interactions through A-site doping for perovskite oxides for key applications such as water splitting, CO₂ electrochemical reduction and N₂ electrochemical fixations.

The latest state of the art on Discrete Element Method (DEM) and the increased computational power are capable of incorporating and resolving complex physics in comminution devices such as tumbling mills. A full 3D simulation providing a comprehensive prediction of bulk particle dynamics in a grinding mill is now possible using the latest DEM software tools. This paper explores the breakage environment in mills using DEM techniques, and how these techniques may be expanded to provide more useful data for mill and comminution device modelling. A campaign of DEM simulations were performed by varying the mill size and charge particle size distribution to explore and understand the breakage environment in mills using DEM techniques. Analysis of each mill was conducted through consideration of the total energy dissipation and the nature of the collision environment that leads to comminution. The DEM simulations show that the mill charge particle size distribution has a strong influence on the mill input power and on the way the energy is distributed across the charge. The smaller particles experience higher energies while the larger experience less, but this variation is strongly dependent on the mill size. The results also showed that the average particle collision energy increases with increasing mill size, whereas its distribution over particle size is strongly influenced by the mill content particle size distribution. The simulations also captured the energy distribution within different regions of the tumbling charge, with the toe impact region having higher impact energies and the bulk shear region having higher tangential energies. Regardless of the mill size most of the energy is consumed by the particles in the mid-size range, which has the highest percentage mass of the total charge distribution.

The breakage characteristics of a two-component ore in a confined bed was studied in this work in order to predict the breakage behaviour of a multi-component ore from the properties of individual components. Bed compression tests with each single component and blended components at different bulk volumetric ratios were carried out at different volume based specific energies and the bed particle size distributions of each component in the mixtures were measured (through magnetic separation). The experimental results show that the breakage product size measured by t10 – the cumulative mass percentage of particles less than 1/10th of the feed size, is linearly proportional to the relative bed porosity reduction, for both single component and multi-component ore. There is a minimum bed porosity reduction to be reached before any breakage occurs and the less competent the ore, the lower the minimum porosity reduction value. Theoretical analysis on bed compression breakage shows that the relationship between product size measured in t10 and the specific comminution energy (Ecs) is not unique and is dependent on the testing conditions. The analysis shows the importance of testing bed breakage at conditions that are independent of bed configurations. Furthermore, models for predicting the product t10 and specific comminution energy of multi-component ore from single component compression data are developed. By compressing the particle bed at the set porosity reduction for each component and few multi-component tests, one can predict the mixture product and mixture energy consumption at any mixture ratios without the needs to physically separate the products in the mixture test.

Dry granulation through roll compaction followed by milling is a widely used pharmaceutical process. The material properties of powders and the roll compaction process conditions affect the strength of ribbons, and subsequently the granule size distribution (GSD). Accurate prediction of the granule size distribution from milling of ribbons with different properties is essential for ensuring tablet quality in the final compaction stage. In this study, MCC, PH-102 ribbons with precisely controlled porosities were produced and milled in a cutting mill and granule size distribution was analysed using QicPic. A population balance model with a new breakage function based on the Weibull function was developed to model the ribbon milling process. Eight model parameters were initially obtained for each ribbon porosity and very good agreement between the model and experimental results was obtained. Sensitivity analysis was then performed and thus reduced the number of model parameters that changed with ribbon porosity to two in the breakage function. The refined model was able to predict the granule size distribution both within and outside the experimental boundaries. It was shown that the model developed in this study has a great potential for predicting granule properties and therefore the optimisation of the dry granulation process.

We report a de Haas-van Alphen (dHvA) effect study on the Dirac type-II semimetallic candidates \emph{M}Al$_3$ (where, \emph{M} = V, Nb and Ta). The angular-dependence of their Fermi surface (FS) cross-sectional areas reveals a remarkably good agreement with first-principle calculations. Therefore, dHvA supports the existence of tilted Dirac cones with Dirac type-II nodes located at 100, 230 and 250 meV above the Fermi level $\varepsilon_F$ for VAl$_3$, NbAl$_3$ and TaAl$_3$ respectively, in agreement with the prediction of broken Lorentz invariance in these compounds. However, for all three compounds we find that the cyclotron orbits on their FSs, including an orbit nearly enclosing the Dirac type-II node, yield trivial Berry phases. We explain this $via$ an analysis of the Berry phase where the position of this orbit, relative to the Dirac node, is adjusted within the error implied by the small disagreement between our calculations and the experiments. We suggest that a very small amount of doping could displace $\varepsilon_F$ to produce topologically non-trivial orbits encircling their Dirac node(s)., Comment: 6 pages and 4 figures

The stability of agglomerated/pelletized ores is one of the key properties for successful heap leaching of complex, low-grade nickel laterite minerals. In this paper, single pellets of saprolitic and goethitic nickel laterite with controlled binder type (tap water and 44 wt.% H2SO4), binder content and pre-set porosity were made by a pellet press and subjected to mechanical strength and rewetting stability tests. The effect of fine/coarse particles ratio on the mechanical strength was also investigated using siliceous goethitic ore. The failure strength of the pellets under different drying conditions was measured and the time taken for the pellets to disintegrate under saturated (soaking) and leaching conditions was recorded. The results showed that, with the same type of nickel laterite, the time taken to disintegration during leaching test is proportional to the pellets tensile strength. Pellets with water as binder are more stable under soak conditions. Furthermore, failure strength for oven dried pellets is greater than that of air dried. With saprolitic nickel laterite (SAP) pellets, their mechanical strength and re-wetting stability can be enhanced by drying the wet pellets or by increasing the binder content in the pellets. The pellets mechanical strength was found to be a good indication of their stability under leaching conditions as well. However, no relationship between the two was observed for goethitic nickel laterite pellets. Refereed/Peer-reviewed

In this research, TiO2 nanoparticles were treated with hydrophobic 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane (fluorosilane) in acidic, neutral and alkaline conditions. The treated nanoparticles were characterized using FTIR spectroscopy, thermal gravimetric analysis, X-ray photoelectron spectroscopy, transmission electron microscopy and X-ray diffraction spectroscopy. Reflectance spectra were obtained using UV–vis diffuse reflectance spectroscopy and band gap energy of the various nanoparticles was determined. Zeta potential measurements were used to evaluate colloidal stability of nanoparticles in aqueous media. The mechanism of fluorosilane adsorption on the surface of TiO2 nanoparticles was investigated using ATR-FTIR spectroscopy and turbidimetric technique. The characterization results revealed that the amorphous fluorosilane adsorbs on the surface of TiO2 nanoparticles in both neutral (pH 6) and alkaline (pH 11) solutions. The values of the band gap energy for all treated nanoparticles were almost the same, in the range of 3.10–3.18 eV. Zeta potential measurements showed that isoelectric point of the TiO2 nanoparticles shifts from 6.8 for untreated TiO2 to 4.4 for treated one. Based on the zeta potential measurement results, it is expected that treated TiO2 nanoparticles in neutral or alkaline conditions have higher colloidal stability and better dispersion in the aqueous solutions. Hydrophobic character of fluoro specious on the surface of nanoparticles leads the treated nanoparticles migrate towards the suspension surface. Therefore, these treated nanoparticles may be useful for developing self-cleaning coatings with minimal destructive effect on the polymeric matrix. Refereed/Peer-reviewed

Nickel laterite pellets with controlled mass, porosity and binder were made by using a pellet press. Both water and sulphuric acid solution were used as binders. The wet pellets were then dried at different conditions and their mechanical strength was measured. Leaching tests were also conducted on single pellet with irrigation of sulphuric acid solution from the top of the pellet. The leached out solutions were collected and nickel recoveries were analysed. The time taken for the pellets to disintegrate during leaching test was also recorded. It was found that the mechanical strength of the pellets was directly related to their dryness, with completely dried pellets having much higher strength. The dry pellet strength was found to increase with increasing binder content and decreasing pellet porosity. The time taken for the pellets to disintegrate during leaching test increased with increasing pellet strength. In comparison to sulphuric acid solution-bound pellets at the same condition, water-bound pellets exhibited higher mechanical strength. Although the nickel leaching rate for water-bound pellets was low at the beginning of the leaching test, the pellets lasted for more than 200 h without disintegration, with 70% of nickel recovered. Refereed/Peer-reviewed

In this paper, ibuprofen from a commercial source and its fractioned samples with narrower size distribution were characterized to assess the effect of particle properties on compaction characteristics. The compaction behavior of binary mixtures of ibuprofen with spray-dried lactose was also studied. The tablet in-die densification rate and tablet out-of-die porosity and tensile strength were measured for all samples. It was found that the particle size of ibuprofen does not affect the yield stress as derived from a Heckel plot, however the yield stress increases with the increase of ibuprofen particle size in the binary mixtures. Particle size also affects the tablet out-of-die properties, with tablet porosity and tensile strength increasing with the decrease in particle size. The effect of adding a weak compacting powder such as lactose on the tablet tensile strength is very much dependent on the ibuprofen particle size and mass ratio of the binary mixtures. Mixing lactose with ibuprofen of similar size in equal mass has no effect on the tensile strength of the tablet whereas mixing it with ibuprofen of larger size reduces the strength compared to ibuprofen alone. Adding a smaller amount of lactose can lead to an increase in tablet strength, even though the particle size of ibuprofen and lactose is quite different. Theoretical analysis on the tablet strength based on particle–particle bond strength was also carried out to explain the experimental results.

On-chip integration of quartz resonators with Si devices opens new opportunities for microsystem miniaturization and enhanced performance. In addition to integrating with electronics, the integration of piezoelectric quartz resonators with other sensors of different material composition is also possible. In this paper, we demonstrate that a VHF SC-cut quartz resonator can be integrated within a high-aspect-ratio Si disk gyro with on-chip heating for locally ovenizing both devices in the same wafer-level vacuum cavity. The SC-cut OCXO can be used to lock the frequency and temperature of the gyro to ≤ 2 ppb and ≤50 μΧ, respectively, for improved accuracy.

This study investigates the flow properties of binary mixtures of both commercial ibuprofen and reprocessed ibuprofen through high shear milling with lactose powders. Ibuprofen is recrystallized in a 30% water–ethanol mixture before high shear wet milling (HSWM). In-situ Process Analytical Techniques (PAT) (Labmax®) is used to study the HSWM process dynamics, with particle size measured by a Lasentec Focused Beam Reflectance Measurement, FBRM®. The flow properties of the binary mixtures of the different ibuprofen particles and its binary mixtures with lactose were measured using a Schulze® RST-XS ring shear tester. Results show that the morphology of ibuprofen was changed from needle to hexagonal like crystals during recrystallization and crystal size was reduced dramatically by HSWM for 1 h. The flowability of milled ibuprofen powders is reduced significantly due to its reduced size and change of surface morphology. Mixing the HSWM ibuprofen powders with lactose enhanced its flow properties. However, the increase of the mixture flowability for HSWM ibuprofen is less significant in comparison to the binary mixtures of lactose with commercial ibuprofen.

Agglomeration of fine mineral particles as a precursor to heap leaching is an important means of enhancing leaching rates and metal recoveries, particularly in processing low grade ores. In this paper, the modelling of a batch drum agglomeration process applied to nickel laterite using population balance model is explored. The coalescence kernels which are linked to feed material and agglomerator operating conditions are reviewed. The use of a physically based coalescence kernel which relates agglomerate layer thickness to binder content and agglomerate consolidation shows great promise for the modelling of the agglomerate size distribution of nickel laterite ore. The model parameters were then used to predict the effect of operating parameters such as binder content on agglomerate size distribution. Refereed/Peer-reviewed

Wet granule breakage is a significant mechanism, particularly in high shear mixer granulation. This paper presents a study of the wet breakage mechanism using a Breakage Only Granulator. Granules with varying powder and liquid binder properties were created using single drop nucleation. These granules were inserted in a Breakage Only Granulator, a high shear mixer granulator with non-granulating cohesive sand as the bulk medium. Two different impellers were used at impeller speeds of 500 and 750 rpm. An 11° beveled edge impeller was used to create both impact and shear in the granulator, and a flat plate impeller was used to minimize impact and maximize shear in the granulator. The fraction of granules which broke during the granulation process was used as a measure of granule breakage within the granulator. These results were compared with Stokes deformation numbers calculated using mean dynamic peak flow stresses measured in unconfined uni-axial compression tests. Results for the beveled edge impeller blade show increasing breakage with increasing Stokes deformation number. Significant breakage was observed at high Stokes deformation number. Increasing impeller speed increased the magnitude of breakage. The Stokes deformations number appears to be a reasonable predictor for granule breakage within the granulator. Results for the flat plate impeller show very little breakage at 500 rpm, and significant breakage for only one formulation at 750 rpm. This suggests that either impact is dominant over shear for breakage within the granulator, or that the two impeller designs give substantially different collision velocities in the granulator. The impeller speed, type and shape have a profound effect on granule breakage in high shear mixer granulators.

Wet granule breakage can occur in the granulation process, particularly in granulators with high agitation forces, such as high-shear mixers. In this paper, the granule breakage is studied in a breakage only high-shear mixer. Granule pellets made from different formulations with precisely controlled porosity and binder saturation were placed in a high-shear mixer in which the bulk medium is a non-granulating cohesive sand mixture. After subjecting the pellets to different mixing time in the granulator, the numbers of whole pellets without breakage are counted and taken as a measure of granule breakage. The experimental results showed that binder saturation, binder viscosity and surface tension as well as the primary powder size have significant influence on granule breakage behaviour. It is postulated that granule breakage is closely related to the granule yield strength, which can be calculated from a simple equation which includes both the capillary and viscous force of the liquid bridges in the granule. The Stokes deformation number calculated from the impact velocity and the granule dynamic strength gives a good prediction of whether the granule of certain formulation will break or not. The model is completely based on the physical properties of the formulations such as binder viscosity, surface tension, binder saturation, granule porosity and particle size as well as particle shape.

OBJECTIVE: Hormonal contraceptives may adversely affect bone mineral density. However racial differences and the reversibility of these changes are poorly understood. This study measured bone mineral density changes during hormonal contraceptive use and after discontinuation in a triethnic population. METHODS: Bone mineral density was measured every 6 months for up to 3 years in 703 white African-American and Hispanic women using oral contraceptives (OCPs) depot medroxyprogesterone acetate (DMPA) or nonhormonal contraceptives and in 68 DMPA discontinuers for up to 2 additional years. Mixed-model regression analyses were used to estimate the percentage change in bone mineral density for each contraceptive method. RESULTS: Over 3 years DMPA and OCP users lost more bone mineral density than did nonhormonal contraceptive users (-3.7% and -0.5% compared with +1.9% at lumbar spine and -5.2% and -1.3% compared with +0.6% at femoral neck respectively). No differences were observed by race in bonemineral density changes that resulted from DMPA or OCP use. However DMPA users aged 16-24 years lost more bone mineral density at the spine (4.2% compared with 3.2% P=.006) and femoral neck (6.0% compared with 4.2% P=.001) than those aged 25-33 years. After DMPA discontinuation women who selected nonhormonal contraceptives gained bone mineral density (+4.9% at spine +3.2% at femoral neck) whereas those who selected OCP recovered spinal (+2.3%) but not femoral neck bone mineral density (-0.7%). CONCLUSION: Use of very-low-dose OCPs may result in a small amount of bone loss. Use of DMPA results in greater bone loss but this is largely reversible at the spine. Use of very-low-dose OCPs after DMPA discontinuation may slow bone recovery.

This paper describes the feeding behaviour ofRousettus leschenaulti Desmarest, 1820 on lychees, the preferred cultivated food of this bat in captive conditions. We found that feeding comprised 25–30% of the total activity of these animals in a flight cage and that feeding durations were not significantly different between two sexes. To evaluate the role of odor and vision in foraging behaviour, we provided animals with artificial lychees, real lychees and artificial lychees soaked in the juice of real lychees and we recorded the number of feeding approaches to the different “fruit” types. The results indicated that bats approached real fruit significantly more than artificial fruit, and that the number of approaches to the soaked artificial fruit was also significantly higher than to the unsoaked artificial fruit. There were no significant differences between sexes in approach rates to any “fruit” type. We discuss the role of different sensory cues in the foraging behaviour of these bats and emphasize that the olfactory cue is important in detecting food resources and discriminating between different kinds of food items.

This paper reports the design, fabrication, and characterization of piezoelectric quartz MEMS magnetometers based on acoustic coupling between resonance modes. The magnetic sensors described herein employ a novel transduction scheme to upconvert the desired near-DC magnetic field signal (using the fundamental flexural mode) onto frequency modulated (FM) sidebands of the primary quartz thickness shear (TS) oscillation at frequencies above 500 MHz. First-generation devices exhibit flexural and TS resonances at 2.77 kHz and at 583.31 MHz, respectively, and magnetic sensitivity of 63.6 V/T was measured with an AC loop current of 9.2 mA. This novel sensing method, intended for electronic compassing, illuminates the interactions between low and high frequency acoustic modes within resonant devices.

In a previous paper, Hoornaert et al. ( Powder Technol. 96 (1998); 116-128) presented data from granulation experiments performed in a 50 L Lodige high shear mixer. In this study that same data was simulated with a population balance model. Based on an analysis of the experimental data, the granulation process was divided into three separate stages: nucleation, induction, and coalescence growth. These three stages were then simulated separately, with promising results. It is possible to derive a kernel that fit both the induction and the coalescence growth stage. Modeling the nucleation stage proved to be more challenging due to the complex mechanism of nucleus formation. From this work some recommendations are made for the improvement of this type of model.

The mechanical properties of a range of agglomerates and particulate coatings have been measured using a nanoindenter. The effect of formulation properties such as powder and binder properties on coating hardness is described. An attempt is also made to measure the fracture hardness with the nanoindenter. The use of indentation technology to measure fundamental agglomerate properties is critically analysed. Based on the indentation measurements and standard attrition test results, the coating hardness is found closely related to the attrition rate under standard conditions and can be used to screen different powder/binder formulations. (C) 2002 Elsevier Science B.V All rights reserved.

Granular gamma-Al2O3 support and 8 wt % CuO/gamma-Al2O3 catalyst were synthesized by a sol-gel granulation method. The pore structure, crush strength, hardness, and elasticity of these sol-gel-derived catalysts were studied and compared with similar commercial catalysts prepared by non-sol-gel methods. Alumina and CuO-coated alumina granular particles prepared by different methods have different macro- and microstructure. The sol-gel-derived granular gamma-alumina and CuO-coated gamma-alumina granular particles have a structure defined by compact packing of uniform, nanosized gamma-alumina crystallites. They are characterized by a more uniform pore size distribution and larger surface area as compared to similar commercial samples with a structure defined by packing of aggregates consisting of nonuniform gamma-alumina crystallites. Because of the differences in the macro- and microstructure, the sol-gel-derived granular samples offer higher crush strength and greater hardness than the commercial samples.

It was previously published by the authors that granules can either coalesce through Type I (when granules coalesce by viscous dissipation in the surface liquid layer before their surfaces touch) or Type II (when granules are slowed to a halt during rebound, after their surfaces have made contact) (AIChE J. 46 (3) (2000) 529). Based on this coalescence mechanism, a new coalescence kernel for population balance modelling of granule growth is presented. The kernel is constant such that only collisions satisfying the conditions for one of the two coalescence types are successful. One constant rate is assigned to each type of coalescence and zero is for the case of rebound. As the conditions for Types I and II coalescence are dependent on granule and binder properties, the coalescence kernel is thus physically based. Simulation results of a variety of binder and granule materials show good agreement with experimental data. (C) 2002 Elsevier Science Ltd. All rights reserved.

MEMS vibratory gyroscopes have recently shown great promise in the field of micro-scale position, navigation, and timing (μPNT), yet their performance often falls short of navigation grade due to losses in the vibratory structure. This paper reports a novel drive mechanism used to excite a cylindrical, all-dielectric micro-shell gyroscope structure. The drive mechanism operates by generating a gradient electric field force from a set of interdigitated electrodes placed adjacent to the gyroscope structure. This novel transduction mechanism enables mechanical actuation of a pristine dielectric structure without the need for direct metallization which could degrade the quality factor (Q) and mechanical performance. Mode spectroscopy in the range of 5-50 kHz is demonstrated with mode amplitudes as large as 0.3 μm for a 10 V drive signal. Quality factors of 12,000 have been measured. Design, fabrication, and experimental demonstration are presented.

Background: Bence Jones proteins or monoclonal immunoglobulin κ and λ free light chains (FLCs) are important markers for identifying and monitoring many patients with B-cell tumors. Automated immunoassays that measure FLCs in urine and serum have considerable clinical potential.Methods: Sheep antibodies, specific for FLCs, were prepared by immunization with pure κ and λ molecules and then adsorbed extensively against whole immunoglobulins. The antibodies were conjugated onto latex particles and used to assay κ and λ FLCs on the Beckman IMMAGETM protein analyzer.Results: The unconjugated antibodies showed minimal cross-reactivity with intact immunoglobulins or other proteins. With latex-conjugated antibodies, κ and λ FLCs could be measured in normal sera and most normal urine samples. Patients with multiple myeloma had increased concentrations of the relevant serum FLC, whereas both FLCs were increased in the sera of patients with systemic lupus erythematosus.Conclusions: We developed sensitive, automated immunoassays for κ and λ FLC measurements in serum and urine that should facilitate the assessment of patients with light chain abnormalities.

Since the summer of 2006, the department of Mechanical Engineering at Oakland University (OU) has been organizing a research experience for undergraduates (REU) program that has been successful at recruiting underrepresented undergraduates in engineering — women in particular. Funded in 2006–2009 and in 2010–2013 through the National Science Foundation REU program and the Department of Defense ASSURE program, this summer REU program focuses on automotive and energy-related research projects. The main purpose of this paper is to share our 6-year experience of organizing and running a summer REU program and to report on the outcomes and short/medium-term assessment results of the program. Also included are some recommendations that we would make to further enhance the success of similar REU programs. We believe that this type of information could prove to be of value to other REU program directors and faculty seeking to organize similar programs.Copyright © 2013 by ASME

Toxic ratio TR is a valuable tool in the discrimination of excess toxicity from baseline effect. Although some authors realized that internal effect concentration or critical body residual (CBR) calculated from bioconcentration factor (BCF) should be used in the TR, the effect of BCF on the discrimination of excess toxicity from baseline effect has not been investigated. In this paper, 951 acute toxicity data to fish (LC50) and 1088 BCFs were used to investigate the relationship between TR and BCF. The results showed that some compounds identified as reactive compounds exhibit excess toxicity, but some do not. BCF is closely related to TR and can significantly affect the TR value. The real excess toxicity which is used to identify reactive chemicals from baseline should be based on the toxic ratio of internal effect concentrations, rather than on the ratio of external effect concentrations, TR. The use of LC50 alone to determine TR can result in errors in TR because toxicokinetics (as estimated by the BCF) are ignored. The foundation in the discrimination of excess toxicity from baseline effect is based on the linear relationship between log BCF and hydrophobicity expressed as log KOW. However, log BCF is not linearly related with log KOW for all the compounds. The BCFs with log KOW >7 or

In this work coalescence of deformable granules in wet granulation processes is modelled. The model accounts for both the mechanical properties of the granules and the effect of the liquid layer at the granule surface. It is an extension to the model of Ennis ct al. (1991) to include the possibility of grannule plastic deformation during collisions. The model is written in dimensionless groups such as viscous and deformation Stokes numbers and the ratio of granule dynamic yield strength to granule Young's modulus (Y-d/E*). These variables are bulk parameters of the powder-binder mixture and also functions of the process intensify. The model glues the conditions for two types of coalescence - type I and type II. Type I coalescence occurs when granules coalesce by viscous dissipation in the surface liquid layer before their surfaces touch. Type II coalescence occurs wizen granules are slowed to a halt during rebound after their surfaces have made contact. The model explains some of the trends observed in the literature, ale pi preliminary validation of the coalescence criterion with drum granulation data is encouraging. An extension is also made to the case of surface dry granules, where liquid is squeezed to the surface during granule information.

Two steps are usually involved in producing high impact polypropylene copolymer in a continuous process. The first is to polymerize propylene using Ziegler-Natta type or more recently metallocene catalyst, and the second is to add ethylene-propylene rubber (EPR). A narrow residence time distribution (RTD) of polymer particles is an important process design and operational target in this process. The broadening of RTD will lead to a widening of copolymer composition distribution in which results in inferior product properties. There are several techniques to obtain a narrower RTD, including by controlling size of particles leaving a well-mixed reactor. In this paper, a dynamic population balance model to track polymer particle age and size is presented. The model is applied to a well-mixed slurry reactor linked to a classifier. Polymer particle growth kinetics including catalyst deactivation with particle age are incorporated. The model agrees well with steady-state analytical solutions and process data for particle age and catalyst efficiency. The classifier acts to significantly narrow particle age distribution. However, the system is very sensitive to small change in feed catalyst size, catalyst deactivation can cause build up of small polymer particles trapped in the system if the feed catalyst size is too low. As a 'soft sensor', the RTD information from the validated model provides valuable insight for operational support. Further applications include strategies of reactor control design and optimization of grade transition policy. (C) 1999 Elsevier Science Ltd. All rights reserved.

A procedure for rapid and reproducible measurement of warfarin is described. This is based on a computer-controlled sequential injection analysis (SIA) system and utilises the phenomenon of enhancement of fluorescence seen when the drug forms inclusion complexes with β-cyclodextrin in aqueous solution. Cyclodextrin and warfarin solutions are sequentially injected and mixed within seconds using the automated system and the fluorescence is then monitored immediately. The calibration curve is linear over the measured concentration range of 0.1 to 1 μg/ml (r2 0.998, n=5) with a limit of detection of 0.02 μg/ml. The measurement is fast with response time of 20 seconds, and is also reproducible with coefficient of variation at 1.5% (n=10) at a concentration of 0.5 μg/ml. Water samples spiked with warfarin were successfully measured using the method.

The widespread application of proteolytic enzymes in many industrial sectors brings considerable benefits to modern industrial manufacturing and to the quality of life for human beings. However, as the enzymes are known potent respiratory sensitising agents, there are potential risks to workers on site and to the general public off-site, if these compounds are released into the atmosphere during their manufacture and processing. To ensure adequate containment within the factory, to protect factory workers and the general public, and to comply with health and safety legislations, it is necessary to monitor airborne concentrations of the enzymes in the workplace atmosphere. At present, however, workplace monitoring of industrial enzymes can only provide exposure data for retrospective use. There is an urgent need to develop rapid and sensitive monitoring methods which provide continuous data on a near real-time basis and detect sudden release of the sensitising material. This paper reviews the existing monitoring methods for proteolytic enzymes in the industrial atmosphere and some recent developments in this important field. Possible strategies for developing integrated sampling and detecting systems for near real-time monitoring of industrial proteolytic enzymes in the manufacturing environment are discussed.

A rapid and sensitive homogeneous assay method has been developed for the determination of subtilisin. The method employs a protein substrate labelled with two fluorescent dyes with fluorescence energy transfer (FET) characteristics. The doubly-labelled substrate was prepared by chemically coupling bovine serum albumin with lucifer yellow and rhodamine dyes. The fluorescence emission from the lucifer labels was initially quenched due to the FET to the adjacent rhodamine labels. However, upon the addition of subtilisin into the labelled substrate solution, increased fluorescence was observed as the enzyme hydrolyzed the substrate and reduced the FET effect. The rate of increase in fluorescence due to substrate hydrolysis was used to calibrate the subtilisin assay. It was linear over the range 0–150 ng of the enzyme (n=8, r2=0.985). The assay was fast with a time of 30 sec to exceed the limit of detection (LOD) signal for 60 ng of subtilisin in 600 μl. In this volume, the LOD for the enzyme was 4.2...