Nucleation and coagulation of particulate matter inside a turbulent exhaust plume of a diesel vehicle

The objective of this study is to develop a physical model to accurately predict the nucleation, coagulation, and dynamics of particulate matter emission from diesel-fueled engines. The uniqueness of this research is that measured particulate matter (PM) size distribution data is not required a priori to solve the nucleation/coagulation equations; instead the PM concentration is predicted based on the fuel sulfur content, fuel to air ratio, exhaust flow rate, and the ambient conditions. This study presents the CFD modeling of an exhaust plume dispersed from a stack pipe of a tractor truck powered by a 330 HP diesel engine. This effort uses the k-epsilon eddy dissipation model to predict the CO2 variation concentration coming out of the stack pipe into the ambient. The effect of the recirculation region near the truck walls on dispersion of CO2 is presented. The predicted results showed an excellent agreement with the experimentally measured values of CO2 concentration, dilution ratio, and the temperature in the wind tunnel. It was predicted that the relative concentration of CO2 from the stack dropped rapidly from 1 to 0.01 within a distance of 2.54 m downstream of the exhaust outlet.;Additionally, the simultaneous effects of nucleation, condensation and coagulation are incorporated in predicting the PM emissions from on-road heavy-duty diesel vehicles. It was predicted that the critical nucleus diameter decreased by approximately 30% and the number concentration increased by a factor of 6 with the increase in relative humidity from 10% to 90% for a fuel with 50 ppm sulfur content. Numerical simulations suggested that the condensation effects are very important near the stack. Ignoring the contribution from condensation term decreased PM count median diameter (CND) from 52 nm to 10 nm. The root mean square error in the numerically predicted particle number concentration was within 14.3% of the experimentally measured values. An increase in CMD from 52 nm to 62 nm was predicted for a distance of 0.51 m from the stack exit to 8.56 m from the stack exit, and the number concentration for the same distance decreased from 8.77 E+6 to 2.1 E+5 No./cm 3

Student’s Use of Hotel Mobile Apps:Their Effect on Brand Loyalty

The purpose of this study is to explore the relationship between the use of hotel mobile applications by students and its effects on brand loyalty. More specifically, this study analyzed the mediating effects of brand loyalty of the hotel company with brand awareness, and brand loyalty as measured by repeat patronage. It has been hypothesized that using mobile hotel apps will have a positive effect on the brand awareness, customer engagement and brand commitment, which in turn positively influences the brand loyalty. The research was drawn from a survey of 100 Purdue university students who are familiar with smartphone use and also because they are the future target market in the hospitality industry. This research will contribute to the hotel in buidling an understanding regarding how hotels can manage their brands using new technology for marketing

Personal Health Information Management by College Students: Patterns of Inaction

Introduction. College students\u27 diverse health information management activities are rarely studied within a personal health context. Our study identified an inactive group of college students and their information management activities to understand what factors determine inactivity. Methods. An online questionnaire was distributed to college students enrolled in a state-owned university in the USA between January and March 2017. A total of eighty-four questions on twelve information management activities grouped by seven types of personal health information were used to identify inactive performers within our student sample. Additionally, potential factors regarding demographics, academics, information resource types, and information workload were tested. Analysis. Our study sample includes 1,408 student responses. K-means clustering segmented the sample into two groups (inactive and active). Group differences between inactive and active personal health information managers were compared. Binary logistic regression was also performed to determine key factors predicting inactivity. Results. The inactive group (N=772, 54.80%) identified more male students, less clinic visits, and health information primarily sought through the Internet and mass media. Additionally, the awareness of personal health information management and training perceptions were found to be significant determinants of the inactivity. The inactive group proved to be lacking in most information management activities, except for discarding, and showed less interests in all types of health documents. Conclusion. Based on the inactive personal health information management group, how to collect, organize, retrieve, backup and migrate personal health documents, should be integrated into a formal college curriculum

The Moderating Effects of Leader-Member Exchange for Technology Acceptance: An Empirical Study Within Organizations

Within the technology acceptance literature, the issue of top management support and commitment has been studied extensively; however, the issue of leadership per se has not been addressed directly. A missing piece of the leadership puzzle as it relates to technology acceptance is an exploration of how top management support gets translated in the organizational hierarchy. This study introduces leader-member exchange (LMX) to better understand this missing piece. Specifically, this research explores the role direct supervisors play in the acceptance process by end users based on the moderated model of LMX and supervisor influence. The empirical test results in the field setting show that LMX is a significant moderator for most of the technology acceptance variables within organizations. The study explores the role of the quality of the relationship between supervisors and employees as end users. It also highlights the role of LMX and supervisor influence as a conduit for the acceptance process among end users in the organization

Inference of Admixture Origins in Indigenous African Cattle.

Present-day African cattle retain a unique genetic profile composed of a mixture of the Bos taurus and Bos indicus populations introduced into the continent at different time periods. However, details of the admixture history and the exact origins of the source populations remain obscure. Here, we infer the source of admixture in the earliest domestic cattle in Africa, African taurine. We detect a significant contribution (up to ∼20%) from a basal taurine lineage, which might represent the now-extinct African aurochs. In addition, we show that the indicine ancestry of African cattle, although most closely related to so-far sampled North Indian indicine breeds, has a small amount of additional genetic affinity to Southeast Asian indicine breeds. Our findings support the hypothesis of aurochs introgression into African taurine and generate a novel hypothesis that the origin of indicine ancestry in Africa might be different indicine populations than the ones found in North India today

栗谷李珥思想研究 : そのTrilogy思想

学位の種別: 課程博士審査委員会委員 : (主査)東京大学教授 川原 秀城, 東京大学教授 福井 玲, 東京大学教授 小島 毅, 東京大学教授 ミュラー アルバートチャールズ, 京都府立大学教授 中 純夫University of Tokyo(東京大学