The nature of interfaces and charge trapping sites in photocatalytic mixed-phase TiO2 from first principles modeling

Mixed phase rutile/anatase catalysts show increased reactivity compared with the pure phases alone. However, the mechanism causing this effect is not fully understood. The electronic properties of the interface and the relative energy of the electron in each phase play a key role in lowering the rate of recombination of electron hole pairs. Using density functional theory and the +U correction, we calculated the bands offsets between the phases taking into account the effect of the interface. Our model included several thousands atoms, and thus is a good representation of an interface between actual nanoparticles. We found rutile to have both higher conduction and valence band offsets than rutile, leading to an accumulation of electrons in the anatase phase accompanied by hole accumulation in the rutile phase. We also probed the electronic structure of our heterostructure and found a gap state caused by electrons localized in undercoordinated Ti atoms which were present within the interfacial region. Interfaces between bulk materials and between exposed surfaces both showed electron trapping at undercoordinated sites. These undercoordinated (typically four) atoms present localized electrons that could enable reduction reactions in the interfacial region, and could explain the increased reactivity of mixed-phase TiO2 photocatalyst materials

Local interfacial structure influences charge localization in titania composites: Beyond the band alignment paradigm

The phase junction of nanocomposite materials is key to enhanced performance but is largely ignored in recent theoretical examinations of photocatalytic interactions in titania-based composites. Computational advances now allow more precise modeling of the electronic and optical properties of composites, and focusing on mixed-phase TiO2 as a model, we use density functional theory (DFT) to interrogate the essential structural feature, namely, the rutile anatase interface, and its relationship to photogenerated charge localization, bulk band alignments, and defect formation. The interfacial region is disordered and distinct from rutile and anatase and contains low coordinated Ti sites and oxygen vacancies, both drivers of charge localization. The relaxations of the interface upon formation of excited electrons and holes determine the final location of charges which cannot always be predicted from bulk band alignments. A detailed understanding of the interfacial phase junction lays the foundation for directed synthesis of highly active and efficient composite photocatalysts

HPC Rankings Based on Real Applications

Extended abstractPerformance benchmarks are used to stress test hardware and software of large scale computing systems. A corporation known as SPEC has developed a benchmark suite, SPEC ACCEL, consisting of test codes representative of kernels in large applications. This project ranks the published results from ACCEL based on different criteria. The goal is to prepare a ranking website for the work-in-progress real-world SPEC HPG benchmark suite, HPC2021 that will soon be released (time frame 2020-2021)

Nutrition and Social Eating Habits Among Seniors Living Independently

Background: Older adults have unique nutritional needs due to physiologic changes that occur as part of the normal aging process. Maintaining adequate nutrition has the potential to reduce morbidity and mortality related to chronic disease, fall risk, dementia and Alzheimer’s disease. Aging also poses an increased risk of isolation and lack of social interaction, particularly noted at meal times. Unintentional weight loss is an independent risk factor for early mortality. Social eating is related to higher food intake, and meal programs can improve nutritional risk for vulnerable seniors. We partnered with the Cathedral Square Corporation (CSC) to assess nutrition and social eating in residents at Heineberg Senior Housing in Burlington, VT and conducted focus groups to determine general nutritional concerns and evaluate potential interventions.https://scholarworks.uvm.edu/comphp_gallery/1033/thumbnail.jp

Concert recording 2019-11-18

[Track 1]. Boutade / Pierre Gabaye -- [Track 2]. Sonata for trumpet and piano, op. 51. III. Finale (Tocatta) / Flor Peeters -- [Track 3]. Concerto [Abridged] / Alexander Artunian -- [Track 4]. Sonata for trumpet and piano. I. Lento, Allegro molto / Eric Ewazen -- [Track 5]. Dance suite from Terpsichore . I. Ballet de Grenoville IV. La Bourre / Michael Praetorius edited and arranged by Allan Dean -- [Track 6]. Quintet no. 1, op. 5. I. Moderato / Victor Ewald -- [Track 7]. Sonata for horn, trumpet and trombone (1922). I. Allegro moderato [Track 8]. II. Andante [Track 9]. III. Rondeau / F. Poulenc

Driving with Parkinson\u27s Disease: Exploring Lived Experience

A growing body of literature has explored the impact of Parkinson\u27s disease (PD) on fitness to drive. As such, evidence now supports the use of specific clinical tests for screening purposes, the predictive validity of risk impressions, and the critical driving errors that predict on-road pass/fail outcomes in this population. However, little is known about the lived experiences of persons with PD as they navigate driving-related concerns such as driving impairments, cessation, potential threats to independence, and community mobility. This qualitative secondary data analysis aimed to explore the driving-related lived experiences of persons with PD. We utilized summative content analysis to identify themes related to driving from transcribed interviews with nineteen community-dwelling individuals with PD who participated in the primary study. Five themes emerged within the analysis: (1) the meaning and significance of driving; (2) driving cessation; (3) modified driving behaviors; (4) factors affecting driving; and (5) accessibility. Participants identified driving as an activity that holds significant importance-both directly (i.e., as a primary activity) and as a means for enabling other activities. This study lays the foundation for the development of client-centred and evidence-informed driving interventions for individuals with PD, as well as the development of driving retirement programs

Exploring aspects of agile software development risk – results from a MLR

Agile software development methods are widely used by software organisations, focusing on short developmental life cycles and customer satisfaction through the iterative and incremental development of software products. Despite their popularity, these methods present risks that may be underappreciated. This paper examines certain risks attributed to agile software development, with a focus on the lack of documentation, scope creep, technical debt and job satisfaction. Through the application of a multivocal literature review, we find that agile software development can greatly benefit projects. However, when agile methods are implemented inappropriately or sub-optimally, projects risk over-spending, delayed or defective software, employee turnover, and overall decreased productivity. Understanding the risks associated with agile software development can help practitioners to achieve higher efficiency and success in their software development projects