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On strike on Mother Language Day: critical reflections, toilet signs and language geneaologies
No full textEnhancing battery cooling and temperature uniformity with longitudinal airflow and fin configurations
Get PDFElectric vehicles rely heavily on a rechargeable battery unit for energy storage. Air cooling, with its simple design and high reliability, is still an effective approach for controlling the battery temperature. However, its thermal performance is poor owing to the air’s limited thermal capacity. To improve the heat transfer coefficient, while also minimising cost, this study adopted various cell configurations in 21,700 cylinder-shaped cell battery modules, including cooling fins with longitudinal airflow. Three-dimensional numerical simulations were conducted for various Reynolds numbers (1,679 ≤ Re ≤ 33,588), using finite volume method to simulate the mass continuity, and momentum and energy conservation equations. The results show that the laminar flow circulation system with longitudinal air-cooling can sustain the battery in optimal operating conditions at a low discharge current (≤ 1.0C), even at a surrounding temperature of 30 °C. By reducing the spiral length by 50 % and altering its position (i.e., front, middle, and back of the cell), the temperature increase is confined to 0.95 °C. The front fin location has the lowest observed temperature of 48.7 °C. Going up the spiral fin loop count from one to five reduces Tmax by 7.4 % and ΔTmax by 29.8 %. Beyond the five spiral loops, the model’s temperature consistency worsens as ΔTmax increases. Polynomial equations were developed to estimate some of the thermal properties of the battery module at various discharge currents
The theory and practice of nonterritorial autonomy in Europe - a historical perspective
No full textThe concept of nonterritorial autonomy (NTA), which aims at separating the notions of the nation and territory, has received many practical implementations—in different forms and guises and in a variety of political settings—since the beginning of the 20th century. It has also become increasingly important for the theoretical debates surrounding issues of ethnic diversity and minority accommodation in a world of nation-states. But as far as the link between NTA theory and the actual case studies exists, it has been primarily connecting theoretical and normative debates with contemporary, post-1991 case studies. Our proposed themed section bridges the existing gap between the theory of NTA and its historical applications in Central and Eastern Europe, providing a fresh perspective on associational, political and legal aspects of nation-building prior to World War II and beyond in the process. Bringing together seven scholars with a long-standing interest in NTA for an energetic multidisciplinary revision of the history of the concept and its practical applications, our themed section aims at shedding new light on broader topics such as nation-building, ethnic relations, minority activism and contemporary normative debates on individual and group rights
Business Analytics with Python: Essential Skills for Business Students
No full textData-driven decision-making is a fundamental component of business success. Use this textbook to help you learn and understand the core knowledge and techniques needed for analysing business data with Python programming.
Business Analytics with Python is ideal for students taking upper level undergraduate and postgraduate modules on analytics as part of their business, management or finance degrees. It assumes no prior knowledge or experience in computer science, instead presenting the technical aspects of the subject in an accessible, introductory way for students. This book takes a holistic approach to business analytics, covering not only Python as well as mathematical and statistical concepts, essential machine learning methods and their applications.
Features include:
- Chapters covering preliminaries, as well as supervised and unsupervised machine learning techniques
- A running case study to help students apply their knowledge in practice.
- Real-life examples demonstrating the use of business analytics for tasks such as customer churn prediction, credit card fraud detection, and sales forecasting.
- Practical exercises and activities, learning objectives, and chapter summaries to support learning
Widely tunable photonic filter based on equivalent chirped four-phase-shifted sampled Bragg gratings
Get PDFWe have developed an integrated dual-band photonic filter (PF) utilizing equivalent chirped four-phase-shifted sidewall-sampled Bragg gratings (4PS-SBG) on a silicon-on-insulator platform. Using the reconstruction equivalent-chirp technique, we designed linearly chirped 4PS Bragg gratings with two π-phase shifts (π-PSs) positioned at 1/3 and 2/3 of the grating cavity, introducing two passbands in the + first order channel. Leveraging the significant thermo-optic effect of silicon, dual-band tuning is achieved through integrated microheaters (MHs) on the chip surface. By varying the injection currents from 0 to 85 mA into the MHs, the device demonstrates continuous and wide-range optical frequency division performance, with the frequency interval between the two passbands adjustable from 52.1 to 439.5 GHz. Four notable frequency division setups at 100, 200, 300, and 400 GHz were demonstrated using a 100 GHz, 1535 nm semiconductor passive mode-locked laser as the light source
Pore network modelling of CO2-shale interaction for carbon storage: Swelling effect and fracture permeability
Get PDFUnderground CO2 storage is a key strategy to achieving net-zero targets by 2050, which requires gigatonne-scale containment of gaseous CO2 in geological formations. Shale rocks play a role in both trapping CO2 and preventing its escape, thus ensuring containment security. However, shale integrity can be compromised upon interaction with CO2, which should be carefully evaluated. This study explores the dynamic behaviour of CO2-shale interaction at the pore scale, focusing on the physiochemical interactions between CO2 and shale, including the impact of shale swelling, where CO2 adsorption causes matrix deformation and alters fracture sizes. Here, we utilise image-based analyses to develop a triple-porosity pore network model (PNM), reflecting the complex nano- to micro-scale structure of shale, to examine CO2 injection into methane-saturated environments. The study particularly focuses on the impact of matrix deformation caused by gas sorption (swelling), competing with mechanical stress effects. Findings indicate that CO2 injection leads to a reduction in fracture permeability by up to 17 % and 10 % in low- and high-density fractured shales, respectively, under high confining pressure (50 MPa), and by 15.5 % and 8 % under lower confining pressure (25 MPa). Although fracture permeability versus CO2 injection pressure reduces monotonically at the lower confining pressure, that of the higher confining pressure is non-monotonic, where the fracture permeability shows an increase due to effective stress change. Additionally, the average fracture aperture size decreases by 50 nm in low-density and 25 nm in high-density fractured shales, highlighting the critical balance between swelling effects and mechanical stresses in the geological sequestration of CO
Semantically Proportioned nDCG for Explaining ColBERT’s Learning Process
No full textIn recent years, dense retrieval approaches have brought significant improvements in information retrieval effectiveness. However, these approaches are significantly more complex than traditional retrieval techniques, decreasing their transparency and explainability. ColBERT, a popular dense retrieval approach, uses a late interaction mechanism (MaxSim) to match the embeddings of tokens in queries and documents. Compared to single-representation dense retrieval approaches, this late interaction offers transparency, in that it allows to observe token-level MaxSim matches between the query and document, and even measure the extent that tokens were matched in exact “lexical” matches, or “semantic” matches. However, previous measures for semantic matching do not take into account how semantic matching influences the model’s effectiveness, i.e. whether it is beneficial or harmful. We propose S-nDCG, which weights the relevance gains in nDCG by the semantic or lexical proportion of matching. In combination with nDCG, this allows to quantify the extent to which a (ColBERT-based) model’s effectiveness can be attributed to semantic or lexical matching, respectively. Through experiments on TREC Deep Learning track queries, we examine how ColBERT’s effectiveness is obtained over training iterations, and find that generally ColBERT learns to rely more heavily on semantic matching throughout training. Surprisingly though, there is a significant decrease of semantic matching during the first 5k training iterations, indicating that even though BERT’s pre-trained token embeddings provide a base for the semantic matching of several different token types, they likely lead to a lot of inaccurate semantic matches at the beginning of training that are addressed by fine-tuning for retrieval
Cash-rich seasoned equity issuers
Get PDFWe document that a substantial fraction of seasoned equity issuers have large pre-offering excess cash holdings. Cash-rich seasoned equity issuers are not easily reconcilable with the traditional pecking order theory on security choice. We examine the role of market timing, agency costs, precautionary motives, repatriation taxes, catering incentives, real options, and negative cash flows in driving seasoned equity offerings (SEOs) by cash-rich firms. We find that cash-rich equity issuers are more overvalued, use the SEO proceeds more opportunistically, and have a worse post-SEO operating and long-term stock price performance than non-cash-rich issuers. However, we do not detect differences in SEO announcement returns between cash-rich and non-cash-rich issuers, suggesting investors underweight firms’ excess cash holdings when assessing an SEO announcement. Overall, our findings predominantly support a market timing motive for SEOs by cash-rich issuers, while other explanations receive mixed to no support. Our results are robust to alternative empirical specifications
TransLeish: Identification of membrane transporters essential for survival of intracellular Leishmania parasites in a systematic gene deletion screen
Get PDFFor the protozoan parasite Leishmania, completion of its life cycle requires sequential adaptation of cellular physiology and nutrient scavenging mechanisms to the different environments of a sand fly alimentary tract and the acidic mammalian host cell phagolysosome. Transmembrane transporters are the gatekeepers of intracellular environments, controlling the flux of solutes and ions across membranes. To discover which transporters are vital for survival as intracellular amastigote forms, we carried out a systematic loss-of-function screen of the L. mexicana transportome. A total of 312 protein components of small molecule carriers, ion channels and pumps were identified and targeted in a CRISPR-Cas9 gene deletion screen in the promastigote form, yielding 188 viable null mutants. Forty transporter deletions caused significant loss of fitness in macrophage and mouse infections. A striking example is the Vacuolar H+ ATPase (V-ATPase), which, unexpectedly, was dispensable for promastigote growth in vitro but essential for survival of the disease-causing amastigotes
Thoraco-abdominal impalement in a dog: The anaesthetic and surgical management
Get PDFA 6.5-year-old, male, neutered Cocker Spaniel presented to the University of Glasgow Small Animal Hospital following impalement on a metal rod while out on a walk. Computed tomography imaging showed the transfixing metal foreign body penetrating the thoracic cavity, diaphragm and abdominal cavity, with associated pneumothorax, pulmonary contusions, hepatic injury, pneumoperitoneum and peritoneal effusion. Exploratory laparotomy and median sternotomy were performed to safely remove the rod. Left lateral liver lobectomy, typhlectomy, diaphragmatic hernia repair, and thoracic and abdominal wall repair were performed in addition to abdominal and thoracic drain placement. Peri-operative administration of blood products was required. Post-operative haemoabdomen developed secondary to liver lobectomy, but only required medical support. The dog was discharged 7 days post-operatively and recovered fully with no long-term complications
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