Search

During the COVID-19 pandemic, much of our social interaction has transitioned from in-person to online. This study examined older adults’ social interaction during COVID-19, online and offline. Participants were recruited from community-dwelling older adults in Central Texas. Data collection took place via the telephone during June-August 2020 (N = 200; age range: 65-92 years; Mean: 73.6; SD: 6.33). Participants used a variety of communication modes, including phone or texting (used by 99% of the participants); email (44%); in person (35%); video chat (31%); social media (24%); and postal mail (4%). Most participants (77%) used more than one communication mode. Participants discussed their preferences for and challenges of technology (i.e., smart phones) and its applications (i.e., video chat, telehealth, and social media). Participants’ self-reported experiences ranged from positive (50%), mixed (35%), to negative (15%). These findings will inform policy and community interventions to promote older adults’ social interactions during the pandemic.

Older adults, disproportionally affected by the COVID-19 pandemic, face health, social and structural vulnerabilities. Their experiences require systematic examination. Our study aimed to examine factors predicting community-dwelling older adults’ experiences during COVID-19. We collected data via the telephone between June-August 2020 from a convenience sample of older adults in Central Texas (N= 200; age range=65-92 years; Mean=73.6, SD=6.33). We conducted multinomial logistic regression analyses to model relationships between self-reported COVID-19 experiences (positive, mixed, negative) and age, gender, race, income, education, frequency of communication with family and friends, feelings of loneliness and amount of COVID-19 information obtained. Factorial analysis revealed no statistically significant interaction effect. Multinomial logistic regression analysis revealed statistically significant main effects of annual household income, feelings of loneliness and amount of COVID-19 information obtained on predicting COVID-19 experiences. Age, gender, race, education, and frequency of communication with family and friends were not significant predictors. The odds of having a positive COVID-19 experience rather than negative experiences increased by 6.94 for an annual household of $60,000- $99,999, and by 6.02 for not feeling lonely. The odds of having a positive experience during COVID-19 rather than mixed increased by 9.90 for an annual household income of $100,000 or more. Participants who reported having “too much information” about COVID-19 were more likely to have mixed experiences compared to those with positive experiences. Our findings underscore the crucial role of financial security and social connections in reducing economic and emotional challenges older adults are facing during this crisis.

Bivariate analysis for ventilator associated pneumonia. Table S2. Outcome analysis with and without tracheostomy using proposed propensity score. (DOCX 15Â kb)

Granulation is an important industrial process used to produce many foods, medicines, consumer products, and industrial intermediate products. This thesis focuses on high shear wet granulation with the specific case study of detergent manufacture using a high shear pin mixer. The key rate process in detergent manufacturing was determined to be the mechanical dispersion of the semi-solid surfactant binder. The pin mixer and mechanical dispersion utilized experiments, population balance models, and discrete element method (DEM) models. The mechanical dispersion of the surfactant binder was studied using a lab scale 6 liter pin mixer. An experimental method was developed to isolate mechanical dispersion from the other rate processes of granulation. Experiments were conducted over a range of impeller speeds, mixing times, and surfactant injection temperatures. Two surfactants where used each with different yield stresses. The yield stresses of both surfactants were characterized using uniaxial compression tests and extrapolated to the impact speeds observed in the pin mixer. Using the yield stress to calculate the Stokes deformation number revealed that the breakage of surfactant would occur at all impact conditions in the pin mixer. The mechanical dispersion results demonstrated that the rate process could be modeled as a breakage process. The results determined that the key parameter governing the mechanical dispersion of paste was the number of revolutions of the impeller. This implies that impaction or sudden stress from the impeller is the mechanism that causes nuclei breakage. The results of the mechanical dispersion experiments were then used to develop a mechanistic semi-empirical model. Because the results indicated that breakage should occur for every impact with the impeller, the model was based on particle impact efficiency between the impeller and nuclei. The impact efficiency was described in a way similar to particle gas filtration where the Stokes number is the characteristic dimensionless group. The population balance model was breakage only and was able to accurately predict the full size distributions of the surfactant nuclei. The results showed that the model was able to accurately account for the effect of tip speed and number of revolutions. This was found by fitting the simulation to a single impeller speed and then predicting the size distributions by varying only the velocity input. Finally, a DEM unit shear cell was developed to understand the transmission of stress from a bulk material to a single large particle of interest similar to surfactant nuclei. The simulation examined the effect of both shear rate, placement of the large particle, and the material properties. The results determined that the material properties used in the simulation had a much greater effect on the shear profile and stress in the shear cell than the effect of the macroscopic shear rate. Using the von Mises yield criteria, the results demonstrated that the shear cell transmitted more stress to the large particle than the yield stress characterized experimentally from the surfactant. The results indicate that the surfactant should break in shear within the pin mixer. Mechanical dispersion has been successfully modeled for the case of detergent granulation in the pin mixer. The combined results demonstrate that mechanical dispersion of surfactant can be modeled as a breakage process. The number of impeller orations and the Stokes number are key parameters to accurately describe and model the simulation. The surfactant should break apart due to both impact and shear within the granulator.

High viscosity surfactant pastes have recently gained popularity in the production of high efficiency laundry detergents due to their ability to increase surfactant loading in granules. When using high viscosity semi-solid binders a unique challenge is presented because it forces granules to be formed primarily by mechanical dispersion; a relatively poorly understood process. Developing mechanistic models of this process will enhance knowledge of mechanical dispersion processes and improve process development for granules produced using this method. Experiments to determine the effect of three process parameters; paste temperature, impeller RPM, and time were carried out in a lab-scale granulator. Binder temperature was varied between 40-60 degrees Celsius to cover paste temperatures from solidification to decomposition. Impeller RPM was varied between 600 -1200 RPM to capture the full range of potential industrial impeller velocities. Mixing time was varied from zero to ten seconds; the time scale of the industrial process. The particle size distribution for the process was determined to rely primarily on mixing time especially at impeller speeds above 900 RPM where fully developed annular flow occurs in the mixer. The Sauter mean diameter of particles was determined to be linearly related to mixing RPM, while temperature was shown to have little effect on the Sauter mean diameter. Experimental data was in relatively good agreement with values predicted by an existing breakage simulation, but could be improved upon. These conclusions will be used in developing a breakage kernel for the process based on material properties.

Davis, Nathan B. Ph.D., Purdue University, December 2015. Granulation Behavior of Ultra-Fine Powders: Examination of Granule Microstructure, Consolidation Behavior, and Powder Feeding. Major Professor: James Litster

Building Information Modeling is considered by the scientific literature as an emerging trend in the architectural documentation scenario, as it is basically a digital representation of physical and functional features of facilities, serving as a shared knowledge resource during their whole life cycle. BIM is actually a process, in which different players act sharing data through digital models in a coordinated, consistent and always up to date workflow. This way, BIM tools were originally meant to ease the design of new architectures, generated by parametric geometries connected through hierarchical relationships of “smart objects” (components self-aware of their identity and conscious of their interactions with each other). However, this approach can also be successfully applied to what already exists: TLS (Terrestrial Laser Scanning) or digital photogrammetry are supposed to be a strategy in which BIM, relying on its own semantic structure, is explicitly used in the representation of existing buildings. Some progresses in the development of this attitude, especially related to sites belonging to the Cultural Heritage, are included in this packet. This presentation, which is used by the author for his Architectural Computer Graphics and Advanced Virtual Modeling courses at the University of Bologna, School of Engineering and Architecture, is an introduction to the use of BIM combined with surveys, highlighting critical aspects and advantages deriving from the application of parametric techniques to the real world domain representation.