A detailed CFD analysis of flow patterns and single-phase velocity variations in spiral jet mills affected by caking phenomena

8siIn this work we present a method to investigate the fluid-dynamics of a 3D, real-scale spiral jet mill when caking is occurring. CFD simulations are employed to deeply study the pressure and the velocity fields of the gas phase when the nozzles inlet pressure and the chamber diameter are varied to mimic the condition generated by the aggregates formation during the micronizaton process. The computational model is built replicating the experimental observation consisting in the fact that most of the crusts form on the outer wall of the chamber. Simulations underline that caking causes the deterioration of the classification capabilities of the system if the gas mass flow rate is kept constant at nozzles, allowing larger particles for escaping the system. It is shown that it is possible to mitigate this phenomenon by gradually reducing the gas mass-flow rate to keep constant the nozzles absolute pressure. This keeps unchanged the fluid spin ratio and the classification characteristics when caking is advancing.openopenSabia, Carmine; Frigerio, Giovanni; Casalini, Tommaso; Cornolti, Luca; Martinoli, Luca; Buffo, Antonio; Marchisio, Daniele L.; Barbato, Maurizio C.Sabia, Carmine; Frigerio, Giovanni; Casalini, Tommaso; Cornolti, Luca; Martinoli, Luca; Buffo, Antonio; Marchisio, Daniele L.; Barbato, Maurizio C

Deep pockets : Exploring the investment decisional process of the crowdinvestor

The digitisation of the economy offered a new context for entrepreneurship to act as a catalyst of change. For example, platforms offered new opportunities for people to co-create value by means of online crowdsourcing. One form of such is equity crowdfunding, where, in pledging to entrepreneurial projects promoted via online marketplaces, people have had the opportunity to support entrepreneurs. However, the presence of massive information asymmetries in such a digital environment has exacerbated adverse selection issues; crowdinvestors find it difficult to evaluate the quality of the promoted projects. The risk they face is finding themselves trapped in failures that would prevent future investments. In turn, this would negatively affect the network effects needed for the industry to survive and thrive. Whilst the research community has fostered the need for increasing transparency in the industry, there is a paucity of research on the challenges the crowd must face when making an investing decision. This would help to develop a better comprehension of their behaviour and in turn a better understanding of to what extent platforms and entrepreneurs could contribute to creating a more transparent and safer investing environment. With this in mind, the present study aims to provide an understanding of how crowdinvestors make investment decisions and what needs they try to address when making an investment decision. By leveraging a framework analysis method, data from 15 crowdinvestors based in the EU and US were analysed. The findings indicate the presence of a bounded-rationality approach through which crowdinvestors combine rational and irrational elements to make investment decisions, thus opening a new perspective to explore the behaviour of crowdinvestors in the context of equity crowdfunding. Moreover, the findings also highlighted that, in making investing decisions, crowdinvestors try to address self-determination needs. In contributing to the investor perspective stream of research in equity crowdfunding research, the present study also offers practical insights for entrepreneurs, platforms, and the policy maker

Using equity crowdfunding to build a loyal brand community: The case of Brewdog

This case study provides a critical understanding of the connection between start-up investment and the development of a loyal brand community. Learners develop an appreciation of how engagement in crowdfunding campaigns can lead to the creation of engaged partners. This is explored through applying the Business Model Canvas to the case of BrewDog, a company that has expanded beyond the niche market of craft brewing to become an international brand. The use of crowdfunding has not only enabled Brewdog to raise the capital to finance expansion but also to develop a special relationship with some of their customers, who through investment and engagement can become partners in the product development process

Radio-Frequency Undulators, Cyclotron Auto Resonance Maser and Free Electron Lasers

We discuss a hybrid Free Electron Laser (FEL) architecture operating with a RF undulator provided by a powerful Cyclotron Auto-Resonance Maser (CARM). We outline the design elements to operate a compact X-ray device. We review the essential aspects of wave undulator FEL theory and of CARM devices

Easy tuning of nanotexture and N doping of carbonaceous particles produced by spark discharge

A better understanding of the effects of carbonaceous particulates in air pollution on human health and on the transmission of viruses requires studies with artificially produced aerosols that mimic the real ones. To produce such aerosols, methods to precisely tailor the morphology as well as the physical and chemical properties of carbon-based nanomaterials are crucial. Here we describe a facile and flexible approach to produce carbon-based nanoparticles with tailored N content by spark discharge utilizing graphite rods. Carbon-based nanoparticles with different nanotexture and N doping could be obtained by simply changing dilution gas (nitrogen, argon) and dilution gas purity (99 and 99.999%). The effect of the discharge frequency (50, 300 Hz) was also explored. The carbon-based nanoparticles were characterized by Fourier transform infrared and X-ray photoelectron spectroscopy, thermogravimetric analysis, and transmission electron microscopy. We find that the nanotexture is strictly linked to the chemical reactivity and to the surface chemistry. The use of N2 as dilution gas allowed for the incorporation of significant amounts of nitrogen (5–7 wt.%) in the carbonaceous particle network mainly as pyrrolic N, graphitic N and N-oxide functional groups

A novel uncoupled quasi-3D Euler-Euler model to study the spiral jet mill micronization of pharmaceutical substances at process scale: model development and validation

In this work we present a novel approach to model the micronization of pharmaceutical ingredients at process scales and times. 3D single-phase fluid-dynamics simulations are used to compute the gas velocity field within a spiral jet mill which are provided as input in a 1D compartmentalized model to calculate solid velocities along the radial direction. The particles size reduction is taken into account through a breakage kernel that is function of gas energy and local solid holdup. Simulation results are validated against micronization experiments for lactose and paracetamol, comparing the model predictions with D10, D50 and D90 diameters values coming from Design of Experiments isosurfaces. The developed model allows for a fair estimation of the outlet particle size distribution in a short computational time, with very good predictions especially for D90 values

Bacillus coagulans LMG S-24828 Impairs Candida Virulence and Protects Vaginal Epithelial Cells against Candida Infection In Vitro

Probiotics are living microbes that provide benefits to the host. The growing data on health pro-motion, following probiotics administration, increased interest among researchers and pharma-ceutical companies. Infections of the lower genital tract in females, caused by a wide range of pathogens, represent one of the main areas for the use of probiotics and postbiotics. Vulvovaginal candidiasis (VVC) affects 75% of women in their reproductive age at least once during their life-time, with 5-8% developing the recurrent form (RVVC). The disease is triggered by the over-growth of Candida on the vaginal mucosa. Here, in order to establish its probiotic potential in the context of VVC, we evaluated the anti-fungal effects of the spore-producing Bacillus coagulans LMG S-24828 against C. albicans and C. parapsilosis as well as its beneficial effects in counteract-ing Candida vaginal infection in vitro. Our results show that both alive B. coagulans and its Cell-Free-Supernatant (CFS) exerted antifungal activity against both fungi. Moreover, alive B. co-agulans reduced hyphal formation, inhibited C. albicans adhesion to vaginal epithelial cells, showed co-aggregation capacity and exerted a protective effect on vaginal epithelial cells infected with C. albicans. These data suggest that B. coagulans LMG S-24828 may provide benefits in the context of Candida vaginal infections

Cell-Free Supernatant from a Strain of Bacillus siamensis Isolated from the Skin Showed a Broad Spectrum of Antimicrobial Activity

In recent years, the search for new compounds with antibacterial activity has drastically increased due to the spread of antibiotic-resistant microorganisms. In this study, we analyzed Cell-Free Supernatant (CFS) from Bacillus siamensis, assessing its potential antimicrobial activity against some of the main pathogenic microorganisms of human interest. To achieve this goal, we exploited the natural antagonism of skin-colonizing bacteria and their ability to produce compounds with antimicrobial activity. Biochemical and molecular methods were used to identify 247 strains isolated from the skin. Among these, we found that CFS from a strain of Bacillus siamensis (that we named CPAY1) showed significant antimicrobial activity against Staphylococcus aureus, Enterococcus faecalis, Streptococcus agalactiae, and Candida spp. In this study, we gathered information on CFS’s antimicrobial activity and on its sensitivity to chemical–physical parameters. Time–kill studies were performed; anti-biofilm activity, antibiotic resistance, and plasmid presence were also investigated. The antimicrobial compounds included in the CFS showed resistance to the proteolytic enzymes and were heat stable. The production of antimicrobial compounds started after 4 h of culture (20 AU/mL). CPAY1 CFS showed antimicrobial activity after 7 h of bacteria co-culture. The anti-biofilm activity of the CPAY1 CFS against all the tested strains was also remarkable. B. siamensis CPAY1 did not reveal the presence of a plasmid and showed susceptibility to all the antibiotics tested

Cell-Free Supernatant from a Strain of Bacillus siamensis Isolated from the Skin Showed a Broad Spectrum of Antimicrobial Activity

In recent years, the search for new compounds with antibacterial activity has drastically increased due to the spread of antibiotic-resistant microorganisms. In this study, we analyzed Cell-Free Supernatant (CFS) from Bacillus siamensis, assessing its potential antimicrobial activity against some of the main pathogenic microorganisms of human interest. To achieve this goal, we exploited the natural antagonism of skin-colonizing bacteria and their ability to produce compounds with antimicrobial activity. Biochemical and molecular methods were used to identify 247 strains isolated from the skin. Among these, we found that CFS from a strain of Bacillus siamensis (that we named CPAY1) showed significant antimicrobial activity against Staphylococcus aureus, Enterococcus faecalis, Streptococcus agalactiae, and Candida spp. In this study, we gathered information on CFS’s antimicrobial activity and on its sensitivity to chemical–physical parameters. Time–kill studies were performed; anti-biofilm activity, antibiotic resistance, and plasmid presence were also investigated. The antimicrobial compounds included in the CFS showed resistance to the proteolytic enzymes and were heat stable. The production of antimicrobial compounds started after 4 h of culture (20 AU/mL). CPAY1 CFS showed antimicrobial activity after 7 h of bacteria co-culture. The anti-biofilm activity of the CPAY1 CFS against all the tested strains was also remarkable. B. siamensis CPAY1 did not reveal the presence of a plasmid and showed susceptibility to all the antibiotics tested

Clinical characteristics and prognostic factors in COVID-19 patients aged ≥80 years

Aim: The aim of the present study was to describe the clinical presentation of patients aged ≥80 years with coronavirus disease 2019 (COVID-19), and provide insights regarding the prognostic factors and the risk stratification in this population. Methods: This was a single-center, retrospective, observational study, carried out in a referral center for COVID-19 in central Italy. We reviewed the clinical records of patients consecutively admitted for confirmed COVID-19 over a 1-month period (1-31 March 2020). We excluded asymptomatic discharged patients. We identified risk factors for death, by a uni- and multivariate Cox regression analysis. To improve model fitting and hazard estimation, continuous parameters where dichotomized by using Youden's index. Results: Overall, 69 patients, aged 80-98 years, met the inclusion criteria and were included in the study cohort. The median age was 84 years (82-89 years is interquartile range); 37 patients (53.6%) were men. Globally, 14 patients (20.3%) presented a mild, 30 (43.5%) a severe and 25 (36.2%) a critical COVID-19 disease. A total of 23 (33.3%) patients had died at 30 days' follow up. Multivariate Cox regression analysis showed that severe dementia, pO2 ≤90 at admission and lactate dehydrogenase >464 U/L were independent risk factors for death. Conclusions: The present data suggest that risk of death could be not age dependent in patients aged ≥80 years, whereas severe dementia emerged is a relevant risk factor in this population. Severe COVID-19, as expressed by elevated lactate dehydrogenase and low oxygen saturation at emergency department admission, is associated with a rapid progression to death in these patients