Combined Heat and Power Dynamic Turbine and Generator Blockset Model with Advanced Grid Support

Increased penetration of distributed generation has created the need for some ne technologies and also the reemergence of some older technologies too. As these technologies penetrate the distribution grid more, engineers need to create models to simulate their performance to be able to accurately detail the impact these resources will have on the grid. Two technologies examined in this paper are a turbine model for a CHP system and an inverter capable of advanced grid support functions. CHP, combined heat and power, is an older technology that is seeing a resurgence especially on the 1-20 MW capacity scale. When building a CHP system with the intention of creating an additional revenue stream by selling power to the grid, a variable speed model is necessary in case of an island scenario. A variable speed model is essential to not cause local grid instability due to large amounts of over or under generation. A variable speed model is developed in this paper to help simulate the dynamics of a natural gas turbine during step and ramp changes in demanded power. Secondly, an inverter capable of advanced grid support functions is developed to meet IEEE 1547-2018 standards with respect to over and under-voltage ride-throughs. Voltage ride-throughs are essential for grid stability, so the grid does not lose a large percentage of power generation at the slightest disturbance. A logic circuit is developed for continuous over and under voltage tripping scenarios and also for return to service once the grid has returned to nominal operating voltage conditions. Future work will address the coupling of these two models together for a complete CHP blockset ready for integration into distribution system models

A Survey of RNA Methylation Within Exon 7 of the Bovine PRKAB1 gene and its Potential Role in Residual Feed Intake Within Livestock Species

Nucleic acids are able to undergo covalent modification in a variety of ways resulting in functional regulation at the epigenetic level. Understanding these epigenetic changes may provide insight into gene regulation, which can be applicable to any field within the life sciences that deal with DNA. Methylation of the carbon at the fifth position in the nucleic acid cytosine (5mC) within DNA is one of the most well documented epigenetic modifications. In eukaryotic organisms, 5mC is associated with down-regulating the gene in which the methylated cytosine is associated with. Although cytosine methylation is well documented at the genetic level, little is known about it at a post-transcriptional level. Cytosine methylation within RNA has been observed in mRNA, tRNA, and rRNA; however, demonstrable rationality for this epitranscriptomic modification has yet to be elucidated. There has been documentation of stable and long-lived RNA molecules containing methylated cytosines, possibly insinuating that a role in RNA stability. The dearth of knowledge regarding post-transcriptional modification of RNA can be explained by the fact 5mC is not easily detectable through most sequencing methods and that 5mC does not affect base pair binding, precluding the use of any probing assays. In this study, a survey of mRNA methylation within exon 7 of the bovine PRKAB1 gene is conducted using skeletal muscle of six individual heifer cows in an effort to better understand the biochemical mechanisms driving differences in observed residual feed intake (RFI) among commercial cattle. Skeletal muscle tissue is used since feed efficiency affects muscle growth within cattle. Here we show methylation of cytosines at the post-transcriptional level is detectable through bisulfite treatment of RNA, followed by conversion to cDNA, PCR amplification and finally restriction digest, showing a potential association of differential methylation within animals that have high and low RFIs. These results give preliminary insight into the bovine AMPK epitranscriptome, while also providing more points of data for post-transcriptional 5mC which could possibly help elucidate patterns in a relatively new sub-field of translational regulation. Finally, this study is the first ever survey of epitranscriptomic markers and their documentation conducted within livestock species

Conformal Invariance of (0,2) Sigma Models on Calabi-Yau Manifolds

Long ago, Nemeschansky and Sen demonstrated that the Ricci-flat metric on a Calabi-Yau manifold could be corrected, order by order in perturbation theory, to produce a conformally invariant (2,2) nonlinear sigma model. Here we extend this result to (0,2) sigma models for stable holomorphic vector bundles over Calabi-Yaus.Comment: 15 pages; references adde

Managing Projects in an Uncertain and Volatile World: Engaging Stakeholders, and Building a Systemic View of Risk

As evidenced through both a historical and contemporary number of over-runs managing projects can be a risky business. Managers are faced with effectively working with a multitude of parties, dealing with a wealth of interlocking uncertainties and frequently undertaking these activities within a compressed timeframe. This paper describes a risk management process developed to assist managers facing such situations. The process explicitly engages a range of stakeholders using a group support system and causal mapping process and provides not only a comprehensive appreciation of the risks identified but also a greater understanding of their subtleties. Using a real case the paper will describe the process and outcomes along with its implications, before reflecting on the insights, limitations and future research

Learning from mixed OR method practice: The NINES case study

Despite continued interest in the use of mixed OR/MS methods, limited attention has been paid in the literature to generic lessons that could be gained from mixing methods . in practice. Many organisational problems demand the use of a mixed method approach and thus recognising and sharing lessons could prove beneficial to both practitioners and researchers. This paper reports on an in-depth evaluation of a case study involving risk identification and quantification of the Northern Isles New Energy Solutions (NINES) project which sought to trial and plan a new energy system. The intervention involved a mixed method approach and client feedback on the efficacy of the approach was sought. The evaluation reported in this paper is carried out using a set of themes taken from the literature and seeks to highlight transferable lessons. The set of lessons that emerge are presented along with their implications for both general OR modelling practice and the specific situation of mixing OR/MS methods. The paper concludes by discussing the implications of the work and directions for future work which will be of interest to both practitioners and researchers interested in mixed method OR/MS work

Conducting rigorous research with subgroups of at-risk youth: lessons learned from a teen pregnancy prevention project in Alaska

In 2010, Alaska Department of Health and Social Services (DHSS) received federal funding to test an evidence-based teen pregnancy prevention program. The grant required a major modification to an existing program and a randomized control trial (RCT) to test its effectiveness. As the major modifications, Alaska used peer educators instead of adults to deliver the program to youth aged 1419 instead of the original curriculum intended age range of 1214. Cultural and approach adaptations were included as well. After 4 years of implementation and data collection, the sample was too small to provide statistically significant results. The lack of findings gave no information about the modification, nor any explanation of how the curriculum was received, or reasons for the small sample. This paper reports on a case study follow-up to the RCT to better understand outcome and implementation results. For this study, researchers reviewed project documents and interviewed peer educators, state and local staff, and evaluators. Three themes emerged from the data: (a) the professional growth of peer educators and development of peer education, (b) difficulties resulting from curriculum content, especially for subpopulations of sexually active youth, youth identified as lesbian, gay, bisexual, transgender, queer, intersex and/or asexual, pregnant, and parenting youth and (c) the appropriateness of an RCT with subpopulations of at-risk youth. Three recommendations emerged from the case study. First, including as many stakeholders as possible in the program and evaluation design phases is essential, and must be supported by appropriate funding streams and training. Second, there must be recognition of the multiple small subpopulations found in Alaska when adapting programs designed for a larger and more homogeneous population. Third, RCTs may not be appropriate for all population subgroups.Ye

Weaning and supplementation increase liveweight gain of Bali (Bos javanicus) cattle of small-holder farmers in Central Lombok, Indonesia

One of the constraints for improving productivity of Bali cattle in west Nusa Tenggara Province is the low growth rate of weaned calves. Results of on-station experiments showed that Sesbania grandiflora (sesbania) supplementation can significantly increase live weight gain of weaned calves. The objective of this experiment was to investigate whether sesbania supplementation can increase live weight gain of weaned calves and improve farmer income. This experiment was carried out in Tandek, Labulia Village (treatment village) and in Kelebuh and Sukaraja villages (control villages) central Lombok District from April to October 2008. A total of 21 calves (9 males and 12 females) aged 237±7 days with initial live weight of 122.3±4.5 kg were monitored in Kelebuh and Sukaraja villages (control villages). During the same period, 25 calves (13 males and 12 females) aged 237±6 days with initial weight of 108.8±4.1 kg were monitored in Tandek Village (treatment village) and fed fresh sesbania at 1% dry matter of live weight. To ensure that sesbania was fed at the recommended level, regular weighing of sesbania offered by each farmer was conducted 2-3 times per week. All calves were weighed every month to determine live weight gain. Farmers from the control villages and other villages were invited to a field day conducted in the treatment village at the end of the experiment. The results showed that sesbania supplementation significantly increased live weight gain (0.36±0.01 kg/day for calves in the treatment village compared to 0.22±0.01 kg/day for those in the control villages), increased body condition and health of the calves and improved farmer income. Weaning management and supplementation with sesbania was very easy to implement so most of the farmers participated in this study stated that they were willing to continue this feeding management

Thermocurrents and their Role in high Q Cavity Performance

Over the past years it became evident that the quality factor of a superconducting cavity is not only determined by its surface preparation procedure, but is also influenced by the way the cavity is cooled down. Moreover, different data sets exists, some of them indicate that a slow cool-down through the critical temperature is favourable while other data states the exact opposite. Even so there where speculations and some models about the role of thermo-currents and flux-pinning, the difference in behaviour remained a mystery. In this paper we will for the first time present a consistent theoretical model which we confirmed by data that describes the role of thermo-currents, driven by temperature gradients and material transitions. We will clearly show how they impact the quality factor of a cavity, discuss our findings, relate it to findings at other labs and develop mitigation strategies which especially addresses the issue of achieving high quality factors of so-called nitrogen doped cavities in horizontal test