Content and Language Integrated Learning: reflections on a pilot module

CLIL, or ‘Content and Language Integrated Learning’, is a term used to describe the practice of teaching content through a foreign language. It represents an educational approach, which can embody a range of different methodologies and has, in recent years, been receiving increased attention in Europe partially as a result of the fact that efforts put into language teaching are not always reflected in the results achieved. This paper begins with a brief overview of developments in the field of foreign language acquisition and how these might relate to the notion of CLIL. It then goes on to describe the design, delivery and evaluation of a module in German language for intermediate, undergraduate students, which incorporates an element of CLIL

Modelling and experimental evaluation of parallel connected lithium ion cells for an electric vehicle battery system

Highlights: • Experimental evaluation of energy imbalance within parallel connected cells. • A validated new method of combining equivalent circuit models in parallel. • Interdependence of capacity, voltage and impedance for calculating cell currents. • A 30% difference in impedance can result in a 60% difference in peak cell current. • A difference of over 6% in charge throughput was observed during cycling. Abstract: Variations in cell properties are unavoidable and can be caused by manufacturing tolerances and usage conditions. As a result of this, cells connected in series may have different voltages and states of charge that limit the energy and power capability of the complete battery pack. Methods of removing this energy imbalance have been extensively reported within literature. However, there has been little discussion around the effect that such variation has when cells are connected electrically in parallel. This work aims to explore the impact of connecting cells, with varied properties, in parallel and the issues regarding energy imbalance and battery management that may arise. This has been achieved through analysing experimental data and a validated model. The main results from this study highlight that significant differences in current flow can occur between cells within a parallel stack that will affect how the cells age and the temperature distribution within the battery assembly

Control of active cell balancing systems : innovation report

Lithium-ion battery packs are increasingly being used for high power and energy applications such as electric vehicles and grid storage. These battery packs consist of many individual cells connected in series and/or parallel. Manufacturing tolerances and varied operating conditions mean that each cell will be different one from another, being able to store different amounts of energy and deliver different amounts of power. This also means some cells will finish charging or discharging before others, resulting in unutilised energy in the remaining cells. Passive balancing systems are often used in multi-cell battery packs to ensure that all of the cells can be fully charged. However, this does not account for differences in cell capacity, meaning that not all cells will be fully discharged. Active balancing systems have been developed to transfer energy between the cells, in theory allowing for stronger cells to compensate for weaker ones. However, their perceived cost and complexity have prevented them from being widely adopted in commercial applications. In this work, an innovative control strategy was developed to determine how and when to energy balance a set of battery cells, with the aim of maximising battery pack energy utilisation. A model-based control system was designed, using state of charge to evaluate the level of energy imbalance between cells. Real-time implementation using second-hand electric vehicle cells and commercial balancing hardware demonstrated that the control strategy can decrease the amount of unused charge in the battery pack from 8% with passive balancing to 1% with active balancing, which has significant impact for battery pack energy throughput, physical size, mass, and long-term health

Analysis of a battery management system (BMS) control strategy for vibration aged nickel manganese cobalt oxide (NMC) Lithium-Ion 18650 battery cells

Electric vehicle (EV) manufacturers are using cylindrical format cells as part of the vehicle’s rechargeable energy storage system (RESS). In a recent study focused at determining the ageing behavior of 2.2 Ah Nickel Manganese Cobalt Oxide (NMC) Lithium-Ion 18650 battery cells, significant increases in the ohmic resistance (RO) were observed post vibration testing. Typically a reduction in capacity was also noted. The vibration was representative of an automotive service life of 100,000 miles of European and North American customer operation. This paper presents a study which defines the effect that the change in electrical properties of vibration aged 18650 NMC cells can have on the control strategy employed by the battery management system (BMS) of a hybrid electric vehicle (HEV). It also proposes various cell balancing strategies to manage these changes in electrical properties. Subsequently this study recommends that EV manufacturers conduct vibration testing as part of their cell selection and development activities so that electrical ageing characteristics associated with road induced vibration phenomena are incorporated to ensure effective BMS and RESS performance throughout the life of the vehicle

Increased use of dental services by children covered by Medicaid: 2000-2010

This report analyzes the use of dental services by children enrolled in Medicaid from federal fiscal years (FFY) 2000 to 2010. The number and percent of children receiving dental services under Medicaid climbed continuously over the decade. In FFY 2000, 6.3 million children ages 1 to 20 were reported to receive some form of dental care (either preventive or treatment); the number more than doubled to 15.4 million by FFY 2010. Part of the increase was because the overall number of children covered by Medicaid rose by 12 million (50%), but the percentage of children who received dental care climbed appreciably from 29.3% in FFY 2000 to 46.4% in FFY 2010. In that same time period, the number of children ages 1 to 20 receiving preventive dental services climbed from a reported 5.0 million to 13.6 million, while the percentage of children receiving preventive dental services rose from 23.2% to 40.8%. For children ages 1 to 20 who received dental treatment services, the reported number rose from 3.3 million in FFY 2000 to 7.6 million in FFY 2010. The percentage of children who obtained dental treatment services increased from 15.3% to 22.9%. In FFY 2010, about one sixth of children covered by Medicaid (15.7%) ages 6-14 had a dental sealant placed on a permanent molar. While most states have made steady progress in improving children’s access to dental care in Medicaid over the past decade, there is still substantial variation across states and more remains to be done

A study of cell-to-cell interactions and degradation in parallel strings : implications for the battery management system

Vehicle battery systems are usually designed with a high number of cells connected in parallel to meet the stringent requirements of power and energy. The self-balancing characteristic of parallel cells allows a battery management system (BMS) to approximate the cells as one equivalent cell with a single state of health (SoH) value, estimated either as capacity fade (SoHE) or resistance increase (SoHP). A single SoH value is however not applicable if the initial SoH of each cell is different, which can occur when cell properties change due to inconsistent manufacturing processes or in-homogeneous operating environments. As such this work quantifies the convergence of SoHE and SoHP due to initial differences in cell SoH and examines the convergence factors. Four 3 Ah 18650 cells connected in parallel at 25 °C are aged by charging and discharging for 500 cycles. For an initial SoHE difference of 40% and SoHP difference of 45%, SoHE converge to 10% and SoHP to 30% by the end of the experiment. From this, a strong linear correlation between ΔSoHE and ΔSoHP is also observed. The results therefore imply that a BMS should consider a calibration strategy to accurately estimate the SoH of parallel cells until convergence is reached

Model based design of balancing systems for electric vehicle battery packs

Battery packs containing multiple cells in series require a balancing system in order to ensure energy and power requirements for the battery pack are maintained throughout its life. Based on the equivalent circuit model (ECM) of a cell, a new framework is proposed which can accommodate a controloriented model of a balancing system while maintaining the same measured input and output as an ECM. This allows for model-based design of the balancing control system and other battery management system functions such as state estimation. Three examples of balancing system models are presented to show how balancing systems can be designed and analyzed. A model-based controller is then designed for one balancing system to show how the framework can be used to generate less heat while removing imbalance at the same rate

Challenges of operational river forecasting

Skillful and timely streamflow forecasts are critically important to water managers and emergency protection services. To provide these forecasts, hydrologists must predict the behavior of complex coupled human–natural systems using incomplete and uncertain information and imperfect models. Moreover, operational predictions often integrate anecdotal information and unmodeled factors. Forecasting agencies face four key challenges: 1) making the most of available data, 2) making accurate predictions using models, 3) turning hydrometeorological forecasts into effective warnings, and 4) administering an operational service. Each challenge presents a variety of research opportunities, including the development of automated quality-control algorithms for the myriad of data used in operational streamflow forecasts, data assimilation, and ensemble forecasting techniques that allow for forecaster input, methods for using human-generated weather forecasts quantitatively, and quantification of human interference in the hydrologic cycle. Furthermore, much can be done to improve the communication of probabilistic forecasts and to design a forecasting paradigm that effectively combines increasingly sophisticated forecasting technology with subjective forecaster expertise. These areas are described in detail to share a real-world perspective and focus for ongoing research endeavors

Daily Sampling of an HIV-1 Patient with Slowly Progressing Disease Displays Persistence of Multiple env Subpopulations Consistent with Neutrality

The molecular evolution of HIV-1 is characterized by frequent substitutions, indels and recombination events. In addition, a HIV-1 population may adapt through frequency changes of its variants. To reveal such population dynamics we analyzed HIV-1 subpopulation frequencies in an untreated patient with stable, low plasma HIV-1 RNA levels and close to normal CD4+ T-cell levels. The patient was intensively sampled during a 32-day period as well as approximately 1.5 years before and after this period (days −664, 1, 2, 3, 11, 18, 25, 32 and 522). 77 sequences of HIV-1 env (approximately 3100 nucleotides) were obtained from plasma by limiting dilution with 7–11 sequences per time point, except day −664. Phylogenetic analysis using maximum likelihood methods showed that the sequences clustered in six distinct subpopulations. We devised a method that took into account the relatively coarse sampling of the population. Data from days 1 through 32 were consistent with constant within-patient subpopulation frequencies. However, over longer time periods, i.e. between days 1…32 and 522, there were significant changes in subpopulation frequencies, which were consistent with evolutionarily neutral fluctuations. We found no clear signal of natural selection within the subpopulations over the study period, but positive selection was evident on the long branches that connected the subpopulations, which corresponds to >3 years as the subpopulations already were established when we started the study. Thus, selective forces may have been involved when the subpopulations were established. Genetic drift within subpopulations caused by de novo substitutions could be resolved after approximately one month. Overall, we conclude that subpopulation frequencies within this patient changed significantly over a time period of 1.5 years, but that this does not imply directional or balancing selection. We show that the short-term evolution we study here is likely representative for many patients of slow and normal disease progression