Photophysical Studies of Beta Phase Formation in Poly(9,9-di-n-alkylfluorenes)

The photophysical changes that take place in Poly(9,9-di-n-alkylfluorenes) upon formation of the beta phase in methylcyclohexane solution are observed by optical spectroscopy. The equilibrium absorption spectra as a function of temperature show that conformational changes occur for all five polymers studied, from the hexyl (PF6) to decyl (PF10) side chains. The spectroscopic indicators of beta phase formation are not observed in PF6, and the trend of beta phase formation efficacy shows an optimal side chain length of 8 carbons. The beta phase formation in PF8, PF9 and PF10 is modelled using a previously reported aggregation model, with limited success. A mechanism for the beta phase formation is proposed, where the interactions between the alkyl side chains provide the chemical energy to overcome the activation energy barrier to planarise the polymer backbone, leading to the extended conjugation length that characterises the beta phase. Excitation spectra show that the beta phase can occur reversibly in dilute solution, most likely by chain folding leading to side chain interactions. The presence of side chain interactions is confirmed by evidence of a PF7-PF9 alternating structure formed in a mixed solution. The same trend of beta phase formation is observed in thin films of these polymers after thermal cycling and warm toluene vapour exposure, showing that side chain interactions are also required for beta phase formation in the solid state. Spectra of PF8 films with controlled keto content show that the energy transfer to the keto sites is mediated by migration, indicating that the beta phase is formed in domains rather than isolated chains, a result which is consistent with the side chain interaction model and other published results. The fraction of beta phase formed is shown to decrease linearly with a greater content of dibenzothiophene (DBT) co-monomer units, up to a cut-off limit of 20%. A statistical model of the distribution of DBT units in the chain is used to find a conjugation length of 9 monomer units, in contrast to a previous estimate but in agreement with the persistence length of PF8 in toluene. These results characterise the beta phase formation mechanism and its effects on the photophysical properties of Poly(9,9-di-n-alkylfluorenes), which is under widespread investigation for more use in efficient blue and white organic LED applications

The Ursinus Weekly, October 5, 1942

Over 135 students speed graduation in summer school • Abraham Hendricks succumbs at home after long illness • President McClure greets largest new enrollment Thursday in chapel • Founders\u27 Day program to honor Dr. Pfahler in dedication ceremony • College buildings to close at 5:30 • Work-study plan attracts 20 men • College opens buildings to 3 summer conclaves • Freshmen stagger through first week of mysteries at Ursinus • Miss Beck takes post as assistant librarian • Ursinus to participate in student war loan program • Swartley sets deadline • Five delegates attend Kanestaki conference • Y handbook guides puzzled freshmen • Letter received from Y\u27s Spanish refugee • Dr. McClure attends Colgate inauguration • The Ursinus College faculty • Here they are - largest enrollment of new students! • Summer sports feature intramurals and softball • Thirty-eight men out for football as second week of practice begins • Stevens is completing plans for inauguration of 150-lb. grid league • Grid schedule to include two home, two away games • Eight holdovers brighten outlook for girls hockey • Mules meet G-burg • Stevens enters his second year optimistically • Over twenty veterans report for soccer practice • Plea for humility made by Snyder, former Y prexy • R. C. Bartman promoted to captain in Navy • Carrying on the traditionhttps://digitalcommons.ursinus.edu/weekly/1739/thumbnail.jp

The Ursinus Weekly, November 2, 1942

First forum hears political, economic stakes of the war • Unity in diversity will be subject of interdenominational conference • Council president tells vespers of religion in college • Fathers\u27 Day banquet to feature addresses by Steward and Ditter • Praise the lord chaplain attended college during \u2728 • Old timers\u27 day to feature Gettysburg game and dance • Curtain Club books play tryouts for Tuesday night • Library increases rake-off on books that are overdue • English Club schedules book review for tonight • Former college nurse attending U.S. Army somewhere in England • Detwiler, Brunner elected to fill council vacancies • Bayne to address chemists • Bears will be out for dragon meat in first home game on Saturday • Three coeds place on all-college team • One fifty pounders to begin scrimmage for opening games • Bakermen drop close 1-0 decision to Swarthmore • Ursinus, Bryn Mawr battle to 2-2 tie • Bryn Mawr jayvees wallop Ursinus coeds 7-1 in opener • Gettysburg whips Drexel by score of 18-0 Saturday • Lady with the Packard Clipper and the dog -- that\u27s Miss Snell • Haverford booters defeat bears 10-0 • Sixty-five couples attend varsity dance on Saturday • IRC adopts plan to study post war reconstructionshttps://digitalcommons.ursinus.edu/weekly/1743/thumbnail.jp

The Aztec Triangle: Three-Way Language Contact in New Spain

Proceedings of the Eighteenth Annual Meeting of the Berkeley Linguistics Society: General Session and Parasession on The Place of Morphology in a Grammar (1992), pp. 22-3

Conformational Preferences of cis-1,3-Cyclopentanedicarboxylic Acid and Its Salts by ^1H NMR Spectroscopy: Energetics of Intramolecular Hydrogen Bonds in DMSO

The conformational populations of cis-1,3- cyclopentanedicarboxylic acid (1) and its mono- and dianion were established in DMSO solution by comparing the vicinal proton−proton coupling constants (^3JHH) obtained in solution to their theoretical counterparts. Geometries used for ^3JHH theoretical estimation (using Karplus-type equations) were obtained from optimized structures at the B3LYP/6-31G-(2d,2p) level. The diacid (1) adopted many conformations, whereas the ionized species (1A mono- and 1B dianion) assumed single conformations. A downfield chemical shift of 19.45 ppm (Δδ_H = 7.43 ppm) observed at −60 °C was indicative of intramolecular hydrogen bonding in 1A, which was later corroborated by determining the ratio of the first (K_1) to the second (K_2) ionization constants. K_1/K_2 in DMSO (1.3 × 10^7) was significantly larger than the value in water (2 × 10). In addition, K_1/K_E = 200 (where K_E is the acidity constant of the monomethylester of 1) was greater than the intramolecular hydrogen bonding threshold value of 2. The calculated intramolecular hydrogen bond strength of 1A was ∼3.1 kcal mol^(−1), which is ∼2.7 kcal mol^(−1) more stable than the values for cis- 1,3-cyclohexanedicarboxylic acid (2A). Thus, the relative energies of intramolecular hydrogen bonding in the monoanions 1A and 2A suggests that 1,3-diaxial conformers are more favored for cyclopentane than for cyclohexane rings

The Ursinus Weekly, April 19, 1943

Judges chose girls to portray roles in May pageant • Thespians to give two Barrie plays • Dean Steward will head men\u27s council; Mildred Halbruegge wins WAA election • College will return stamps for Easter • Y officers installed at vespers service • Medical relief group asks students for biology kits • Lenten speaker interprets Jesus\u27 dreams as universal • Ursinus TKA cancels debating conference • Choir and Y\u27s present Easter service tonight • Dr. Theo. Herman speaks to brotherhood of St. Paul • Women debates accept twelve new members • France forever movement represents upholders of nation\u27s pre-war spirit • Students under 21 need parents\u27 ok to give blood • Exchanges placed in library • Penn dean to speak here • Softball tilts begin for dorm players • Spring season starts for women\u27s sports with varied program • Attention, girls!! • Men line up baseball teams to determine class champs • Girls lost only two tennis matches in last six years of intercollegiates • Norwegian girl tells startling story of life in Europe under Nazi heel • Beardwood elects officers • Dr. White reviews book • Music Club now organizing Y sing booklet of 53 songs • German Club plans social • Hope Le Bar Roberts talks at AAUW meeting April 14 • Airplane spotter to speak • Robert Tredinnick becomes new president of IRC • Joyce Behler leads dancing at French Club meetinghttps://digitalcommons.ursinus.edu/weekly/1761/thumbnail.jp

Ergonomics and Occupational Health Issues in Diagnostic Imaging: A Survey of the Situation at the Korle-Bu Teaching Hospital

The practice of Radiology requires the performance of many labour-intensive tasks relating to the delivery of quality patient care. Poor working conditions could lead to increased adverse effects on the professional which, in turn may have deleterious effects on the work performance; hence the need to ensure effective working conditions. The study sought to assess the ergonomic situation of the various imaging units at the Korle-Bu Teaching Hospital (KBTH). The subjects were final year student radiographers, qualified diagnostic Radiographers, and Radiologists at the KBTH. A quantitative research design, using a descriptive survey, was conducted as the researcher sough to obtain information about what existed with respect to the conditions within the imaging departments. A response rate of 95% was achieved.  The majority of the respondents (87.3%) lacked training on workplace ergonomics.  Additionally, there were ergonomic injuries that existed among the participants and these affected their health. The ergonomic situations at most imaging units within KBTH were not up to standard and these affect the productivity and health of the professional in the form of musculoskeletal disorders, thus requiring attention. Key words: Ergonomics, Radiographers, Radiologists, Sonographers, Musculoskeletal injurie

Low-cost sensory glove for human-robot collaboration.

Masters Degree. University of KwaZulu-Natal, Durban.Human Robot Collaboration (HRC) is a technique that enables humans and robots to co-exist in the same environment by preforming operations together. HRC has become a vital goal for industry to achieve progress towards the fourth industrial revolution (Lotz, Himmel, & Ziefle, 2019) as it focuses on creating advanced production/manufacturing plants that have high levels of productivity, efficiency, quality and automation. Sensory gloves can be used to enhance the Human Robot Collaboration environment in order to achieve progress towards Industry 4.0. It can provide a safe environment where humans and robots can interact and work in conjunction. However, challenges exist in terms of cost, accuracy, repeatability and dynamic range of such devices. The project researched and developed a low-cost sensory glove to enable a user to collaborate with an industrial robot in a production environment. The sensory glove was used to provide a process whereby humans could collaborate with the robot through physical interaction under safe conditions. The sensory glove used IMU sensors in order to track the orientation of the user’s hand accurately. An algorithm was developed and designed to extract the data from the glove and create a simulated three-dimensional render of the hand as it moved through free space. This involved the design and development of an electronic system architecture that powers the glove. A control system was developed to enable the extraction of data and create the simulated three-dimensional hand model. It produced the image that the robot would sense when interacting with the worker. Testing was conducted on the cost, accuracy, dynamic range, repeatability and potential application of the system. The results showed that it was an innovative and low-cost method for humans and robots to collaborate in a safe environment. The apparatus established a process whereby humans and robots could perform operations together