1,103 research outputs found
Measurement of the W charge asymmetry in production with jets using 5 inverse-femtobarns of data measured at sqrt(s)=7 TeV with CMS
A measurement of the electron charge asymmetry in p+→W production in association with jets at sqrt{s}=7 TeV is presented. The dataset corresponds to an integrated luminosity of L=5fb^-1 recorded by the CMS detector
in proton-proton collisions at the LHC. The sample represents a large increase in statistical precision with respect to previous
CMS results and describes a first study of charge asymmetry measured in p+p→W+1 jet events. Full comparisons to previous results and theoretical predictions are provided and
recommendations for extending the analysis to produce valuable input for future PDF models are made
Flying Wing Aerodynamic Design and Airbrake Integration
During the 2022-2023 Academic year, the defense contractor, AeroVironment, tasked the Unmanned Aerial Systems Laboratory at Old Dominion University with designing an autonomous drone platform. A brief summary of the aerodynamic requirements included that the drone should cruise at a target cruise speed of 30m/s, the drone would operate up to an altitude of 1500m and be able to land within a 20m radius of a designated landing spot. The laboratory chose a flying wing model. Additionally, the aircraft would have an airbrake system integrated into the platform.
The aerodynamic requirements were configurated through the use of a ‘constraint diagram’. The airfoil was selected by conducting a literature search and constructing an airfoil performance matrix. The airframe was designed computationally using the software XFLR5, a Vortex Lattice Method solver for low Reynolds numbers. The airframe was then flight tested and validated using the autopilot logs to confirm the predicted aerodynamic performance.
The airbrake system was implemented post flight testing of the airframe and was designed using Stat-Ease 360 software, which is a compiled GUI interface used to generate designed experiments. A response surface was generated using airbrake models created in XFLR5. This response surface was then used to find a list of potential airbrake solutions. The most promising solutions were selected to be wind tunnel tested. After successful wind tunnel testing, another design of experiments was created to flight test the airbrake system. The airbrake system unfortunately was never able to be flight tested due to complications with a launcher system designed outside of the scope of this thesis. Alternatively, the methodology of how to flight test an airbrake system was documented and a trainer aircraft fitted with an airbrake system was flight tested with all data logged and analyzed postflight.
After validating the aerodynamic profile and airbrake system, the aerodynamic performance of the aircraft outperformed all predictions. Additionally, while the airbrake system itself was never flight tested, all computational and experimental data points toward encouraging results. If the launcher system is improved, a future flight test using the methodology created could confirm the performance of the airbrake system
The Significance of the Ancient Standing Stones, Villages, Tombs on Orkney Island
The Orkney Islands make up an archipelago north of Scotland. A collection of ancient stone structures believed to predate the pyramids of Egypt and the golden age of China is found in this remote corner of the globe. Archaeological evidence from these islands is consistent in several ways with the biblical account in Genesis 11:1-9 that describes an advanced civilization at Babel in Mesopotamia, the confusion of languages, and the dispersion of groups of people throughout the world. Descendants of these dispersed people very likely built the advanced Orcadian civilization that prospered over 4000 years ago
Using digital logs to reduce academic misdemeanour by students in digital forensic assessments
Identifying academic misdemeanours and actual applied effort in student assessments involving practical work
can be problematic. For instance, it can be difficult to assess the actual effort that a student applied, the
sequence and method applied, and whether there was any form of collusion or collaboration. In this paper we
propose a system of using digital logs generated by selected software tools (such as FTK- Forensic Toolkit and
EnCase), for the purpose of identifying the effort and sequence of events that students followed to complete their
learning activities, (say, arriving at conclusions relating to an assessment question) and thereby determining
whether it is likely that an academic misdemeanour may have occurred. The paper elaborates on an assessment
exercise conducted with a cohort of 67 students in a specific class of disciplinary learning, highlighting the
process that students have to follow, and then proceeds to show in some details how selected logging facilities can
be used to provide evidence that students may have committed an academic misdemeanour
Podcast PD
Reports of police corruption are becoming more and more common in American media. In this podcast, we will discuss the distrust between the police and the community, some of the causes of the problem, and will address ways to resolve it. Throughout the duration of the podcast, we will provide the viewpoint of both sides and try to explain why they feel the way they do. To get the community’s input, our group decided to poll random students across campus to get a better understanding on their view of the police state in the US. For the police’s side, we decided to interview an officer for his input on why these controversial stories are being displayed all over the media, and asked what he thinks should be done to improve the relationship between the two parties. By including the thoughts of the opposing sides, as well as using data from some of the instances reported in the media, we hope that our listeners will gain a better understanding of the issue and proactively try to improve the relationship between the community and the police
Setting Priorities for Space Research: Opportunities and Imperatives
This report represents the first phase of a study by a task group convened by the Space Studies Board to ascertain whether it should attempt to develop a methodology for recommending priorities among the various initiatives in space research (that is, scientific activities concerned with phenomena in space or utilizing observations from space). The report argues that such priority statements by the space research community are both necessary and desirable and would contribute to the formulation and implementation of public policy. The report advocates the establishment of priorities to enhance effective management of the nation's scientific research program in space. It argues that scientific objectives and purposes should determine how and under what circumstances scientific research should be done. The report does not take a position on the controversy between advocates of manned space exploration and those who favor the exclusive use of unmanned space vehicles. Nor does the report address questions about the value or appropriateness of Space Station Freedom or proposals to establish a permanent manned Moon base or to undertake a manned mission to Mars. These issues lie beyond the charge to the task group
Polyanionic Ligand Platforms for Methyl- and Dimethylaluminum Arrays
Trimethylaluminum
finds widespread applications in chemical and materials synthesis,
most prominently in its partially hydrolyzed form of methylalumoxane
(MAO), which is used as a cocatalyst in the polymerization of olefins.
This work investigates the sequential reactions of trimethylaluminum
with hexaprotic phosphazenes (RNH)6P3N3 (=XH6) equipped with substituents R of varied
steric bulk including tert-butyl (1H6), cyclohexyl (2H6), isopropyl (3H6), isobutyl (4H6), ethyl
(5H6), propyl (6H6), methyl (7H6), and benzyl (8H6). Similar to MAO, the resulting complexes of polyanionic
phosphazenates [XHn]n−6 accommodate multinuclear arrays
of [AlMe2]+ and [AlMe]2+. Reactions
were monitored by 31P NMR spectroscopy, and structures
were determined by single-crystal X-ray diffraction. They included 1H4(AlMe2)2, 1H3(AlMe2)3, 2H3(AlMe2)3, 3(AlMe2)4AlMe, 4HÂ(AlMe2)5, 4(AlMe2)6, {5HÂ(AlMe2)4}2AlMe, 5(AlMe2)6, 6(AlMe2)6, {7(AlMe2)4AlMe}2, and 8(AlMe2)6. The study shows that subtle
variations of the steric properties of the R groups influence the
reaction pathways, levels of aggregation, and fluxional behavior.
While [AlMe2]+ is the primary product of the
metalation, [AlMe]2+ is utilized to alleviate overcrowding
or to aid aggregation. At the later stages of metalation, [AlMe2]+ groups start to scramble around congested sites.
The ligands proved to be very robust and extremely flexible, offering
a unique platform to study complex multinuclear metal arrangements
Synthesis of 2,6-trans- and 3,3,6-Trisubstituted Tetrahydropyran-4-ones from Maitland-Japp Derived 2H-Dihydropyran-4-ones: A Total Synthesis of Diospongin B
6-Substituted-2H-dihydropyran-4-one products of the Maitland-Japp reaction have been converted into tetrahydropyrans containing uncommon substitution patterns. Treatment of 6-substituted-2H-dihydropyran-4-ones with carbon nucleophiles led to the formation of tetrahydropyran rings with the 2,6-trans-stereochemical arrangement. Reaction of the same 6-substituted-2H-dihydropyran-4-ones with l-Selectride led to the formation of 3,6-disubstituted tetrahydropyran rings, while trapping of the intermediate enolate with carbon electrophiles in turn led to the formation 3,3,6-trisubstituted tetrahydropyran rings. The relative stereochemical configuration of the new substituents was controlled by the stereoelectronic preference for pseudo-axial addition of the nucleophile and trapping of the enolate from the opposite face. Application of these methods led to a synthesis of the potent anti-osteoporotic diarylheptanoid natural product diospongin B
- …