Investigating the Liquid State of Carbon

Carbon materials have a many contemporary applications and new carbon allotropes are being discovered. However, while graphite and diamond are well understood, very little is known about the liquid state of carbon due to the high temperatures (above 5,000 K) and pressures (above 10 MPa) required for its formation. Initial studies used electrical heating to determine the melting point of graphite and the resistivity of liquid carbon. More recent studies used non-thermal laser melting to generate a metastable liquid that was studied with visible reflectivity and X-ray spectroscopies. Shock waves have also been used to transiently generate liquid carbon. Theoretical calculations of liquid carbon initially suggested the possibility of a liquid-liquid phase transition, but later ab initio quantum mechanical simulations showed only a continuous change in liquid coordination as its density increased. In this dissertation, extreme-UV (EUV) reflectivity and chirped coherent anti-Stokes Raman spectroscopy (c-CARS) were used to study non-thermally melted liquid carbon. Femtosecond laser pulses at 250 nm with a fluence of 0.45 J/cm2 (3.5 x 1012 W/cm2 intensity) were used to generate liquid carbon from an amorphous carbon substrate and the time evolution of EUV reflectivity was probed. EUV wavelengths from 20 to 42 nm were used with both s and p polarizations. The reflectivity decreased at all wavelengths probed as the material expanded and ablated. For wavelengths below 32 nm, the reflectivity decay time was less than ~2 ps. This time constant describes the lattice dynamics after melting, while above 32 nm, the reflectivity is also sensitive to the hot electron plasma generated by the melting pulse. From these results and equations for the behavior of a shock wave in a material, the electron temperature of the melted material was found to be 0.30 ± 0.6 eV. The reflectivity at two different polarizations was also used to calculate the complex refractive index of the material as it evolved over time. C-CARS spectra were obtained for highly ordered pyrolytic graphite (HOPG) and glassy carbon using CARS pump wavelengths of 400 nm and 800 nm. These spectra showed strong G peak resonance (1580 cm-1), corresponding to the relative vibrations of sp2 carbons in the material. The D peak (~1350 cm-1) resonance seen in Raman scattering of disordered graphite films was not observed in the CARS spectra. As this mode occurs when the excited electron scatters from a defect or phonon, it could be that the stimulated Stokes emission that occurs during the CARS process prevents such scattering. The sample was melted with an 800 nm, 90 fs laser pulse with fluences from 0.40 to 0.85 J/cm2 (intensities of 4.4 x 1012 to 9.4 x 1012 W/cm2). Delay times of less than 500 fs and as long as 100 ps all showed no broadening or shifting of the G peak, as would be expected for damaging and disordering of the material; only an intensity change is seen as the material ablates. Microscope images show permanent damage to the substrate and the fluences and times studied were comparable to those used in published reflectivity studies of liquid carbon. To advance the study of liquid carbon, a soft X-ray second harmonic generation (SHG) technique was developed and explored. X-ray absorption provides element-specific information on the electronic structure of a material that is sensitive to the environment around the element. Combining this with the interface specificity of SHG, provides a useful technique for studying solid-solid interfaces that are difficult to study otherwise. Our first soft X-ray SHG experiments on graphite films showed that the technique was indeed highly interface specific. The technique was also sensitive to resonance amplification when the input photons were at or above the carbon K-edge. A second experiment compared the boron/vacuum interface to a buried boron/carbon (Parylene-N) interface. The technique was sensitive to interface effects, showing larger SHG intensity at the boron K-edge for the boron/Parylene-N interface compared to the boron/vacuum interface. Ab initio quantum simulations were used to calculate the soft X-ray SHG spectra of these systems, verifying the interface sensitivity of the technique

Nifty Data Structures Projects

For computer science, and many technical fields, it is recognized that projects with real-world applicability play a significant roll in what students get out of the course. Creating applicable projects for upper division such as our data structures classes is very difficult and time consuming. We have utilized the Nifty assignments concept and applied it locally to an upper division data structures course. Our primary goal is to provide a forum for the sharing of data structure project ideas and materials (as applicable).https://digitalscholarship.unlv.edu/btp_expo/1062/thumbnail.jp

DINAMIKA SOSIAL EKONOMI MASYARAKAT YANG TINGGAL DI SEKITAR KAWASAN PERTAMBANGAN

This study uses Kingsley Davis Social Dynamics theory to solve problems in the field with the Ethnographic Method, data collection using observation techniques and in-depth interviews and purposive sampling informant selection techniques. Data were analyzed descriptively. This Nickel mining activity by PT NPM took experts on agricultural land belonging to the people of Matarape Village without the consent of the local community, the acquisition of agricultural land that reached 300 hectares made the farmers in Matarape Village suffer huge losses, not only losses, their economy also became paralyzed. In total, this is because the farmers can no longer produce cashew nuts as their source of income. The damage to agricultural land carried out by PT NMP triggered a conflict between the community and the PT NPM company, where the majority of people who work as farmers demanded compensation for the destruction and use of agricultural land which reached up to 300 hectares was used for road construction and mining activities of PT. This NPM also resulted in changes in the livelihoods of the people of Matarape Villag

Performance Evaluation of AODV, DSR, DYMO & ZRP in Cost 231 Walfisch-Ikegami Path Loss Propagation Model

A Mobile Ad hoc NETwork is a kind of wireless ad-hoc network, and is a self configuring network of mobile routers connected by wireless links. Mobile Ad-Hoc Network (MANET) is a wireless network without infrastructure. Self configurability and easy deployment feature of the MANET resulted in numerous applications in this modern era. Efficient routing protocols will make MANETs reliable. Various research communities are working in field of MANET and trying to adopt the protocols and technology in other applications as well. In this work, we present investigations on the behavior of various routing protocol of MANET with a Cost 231 Walfisch-Ikegami Propagation Model. We evaluate the performance of four different ad-hoc routing protocols on four performance metrics such as Average Jitter, Average End-to-End Delay, Throughput, and Packet Delivery Fraction with varying Pause Time. From the simulation results it is concluded that DSR is better in transmission of packets per unit time and maximum number of packets reached their destination successfully with some delays, i.e. PDF & Throughput is more and Average jitter & end-to-end delay is less. Whereas AODV & ZRP having almost same values in all of the performance metrics, they transmit packets with very less delay but transmits less packets to their destination as compare to DSR.

Assessing the Impact of International Natural Resource Management Research: The Case of Zero Tillage in India's Rice-Wheat Systems

A conservative ex-ante assessment of supply-shift gains alone (excluding social and environmental gains), shows that the investment in zero tillage (ZT) R&D by the Rice-Wheat Consortium and CIMMYT was highly beneficial with a benefit-cost ratio of 39, a net present value of US$ 94 million and an internal rate of return 57%. Sensitivity analysis highlights the influential role of the yield gain, the contribution of reduced tillage (i.e. partial adoption) and the assumed time-lag. Significant positive spillovers of sunk ZT R&D costs both previous and from elsewhere - also contributed to the high returns. The case thereby highlights the potential gains from successful technology transfer and adaptation. The case however also underscores that international NRM research can have a high return, particularly when it has wide applicability.natural resource management research, impact assessment, economic surplus, zero tillage, Q11, Q12, Q16, Crop Production/Industries, Resource /Energy Economics and Policy,

Assessing the Impact of International Natural Resource Management Research - The Case of Zero Tillage in India’s Rice-Wheat Systems

A conservative ex-ante assessment of supply-shift gains alone (excluding social and environmental gains), shows that the investment in zero tillage (ZT) R&D by the Rice-Wheat Consortium and CIMMYT was highly beneficial with a benefit-cost ratio of 39, a net present value of US$ 94 million and an internal rate of return 57%. Sensitivity analysis highlights the influential role of the yield gain, the contribution of reduced tillage (i.e. partial adoption) and the assumed time-lag. Significant positive spillovers of sunk ZT R&D costs both previous and from elsewhere - also contributed to the high returns. The case thereby highlights the potential gains from successful technology transfer and adaptation. The case however also underscores that international NRM research can have a high return, particularly when it has wide applicability.natural resource management research, impact assessment, economic surplus, zero tillage

Assessment of Current Level of Compliance to COTPA (The Cigarette and other Tobacco Product Act) 2003 in Mysore District of State of Karnataka, India

Tobacco is the single greatest cause of death globally. As many as half of people who use tobacco die from the results of this use. The World Health Organization (WHO) estimates that each year tobacco causes about 6 million deaths (about 10% of all deaths) with 0.6 million of these occurring in non-smokers due to second-hand smoke. In the 20th century, tobacco is estimated to have caused 100 million deaths. The government of India implemented Cigarettes and other Tobacco Products Act of 2003, which prohibits smoking in public places, advertisement and regulation of trade and commerce, production, supply and distribution, direct or indirect advertisement, sponsorship and promotion of tobacco products and sale to and by minors and prohibition of sale around educational institutions. In order to find the compliance of COTPA in Mysore district, the study was conducted with the help of State Institute of Health & Family Welfare, Karnataka, and the International Union against Tuberculosis and Lung Disease. The objective of the study was to assess the current level of compliance to various sections of COTPA in Mysore district. For compliance monitoring, an observation checklist was used to assess the compliance to different sections of the Act which has been developed by the “International Union against Tuberculosis and Lung Disease.” A total of 410 public places, 400 points of sale, and 400 educational institutions were observed to assess the compliance to the COTPA Act (2003). It was found that there is clear violation of the Act in majority of the places

Role of Ranking Algorithms for Information Retrieval

As the use of web is increasing more day by day, the web users get easily lost in the web's rich hyper structure. The main aim of the owner of the website is to give the relevant information according their needs to the users. We explained the Web mining is used to categorize users and pages by analyzing user's behavior, the content of pages and then describe Web Structure mining. This paper includes different Page Ranking algorithms and compares those algorithms used for Information Retrieval. Different Page Rank based algorithms like Page Rank (PR), WPR (Weighted Page Rank), HITS (Hyperlink Induced Topic Selection), Distance Rank and EigenRumor algorithms are discussed and compared. Simulation Interface has been designed for PageRank algorithm and Weighted PageRank algorithm but PageRank is the only ranking algorithm on which Google search engine works.Comment: Keywords: Page Rank, Web Mining, Web Structured Mining, Web Content Minin

Assessing the impact of international natural resource management research: The Case of Zero Tillage in India's rice-wheat systems

A conservative ex-ante assessment of supply-shift gains alone (excluding social and environmental gains), shows that the investment in zero tillage (ZT) R&D by the Rice-Wheat Consortium and CIMMYT was highly beneficial with a benefit-cost ratio of 39, a net present value of US$ 94 million and an internal rate of return 57. Sensitivity analysis highlights the influential role of the yield gain, the contribution of reduced tillage (i.e. partial adoption) and the assumed time-lag. Significant positive spillovers of sunk ZT R&D costs - both previous and from elsewhere - also contributed to the high returns. The case thereby highlights the potential gains from successful technology transfer and adaptation. The case however also underscores that international NRM research can have a high return, particularly when it has wide applicability.natural resource management research; impact assessment; economic surplus; zero tillage