POPULAR INFORMATIONAL PRIORITIES IN AGRICULTURAL EXTENSION

Due to agriculture's increasingly complex technical and economic environment, the diversity of information required for competitive and profitable farming is growing as never before. With constant and, in some cases, reduced resources for agricultural programs, Extension must exercise special care in prioritizing informational efforts to best meet farm-client needs and retain an important base of public support. This paper presents a method of identifying popular informational priorities in Agricultural Extension. The method is illustrated by application to dairy programming in Massachusetts.Teaching/Communication/Extension/Profession,

In-situ electronics and communications for intelligent energy storage

Lithium-ion batteries are increasingly common in high-power, safety–critical applications such as aerospace, spaceflight, automotive and grid storage. The voltage and power specifications of such applications usually require large numbers of individual cells combined in series and parallel to form a battery pack. It is then the role of the Battery Management System (BMS) to monitor these cells condition and ensure they remain within safe operating limits. To minimise cost and complexity, it is typical to monitor only a fraction of the cells in a battery pack. This creates potential safety and reliability issues and requires conservative limits imposed on the overall system to ensure safe operation. This is insufficient in high-power, safety–critical applications and thus alternative approaches to battery management are required. Here we demonstrate the development of novel miniature electronic devices for incorporation in-situ at a cell-level during manufacture. This approach enables local cell-to-cell and cell-to-BMS data communication of sensor data without the need for additional wiring infostructure within a battery module assembly. The electronics firmware and hardware integration within the cell’s electrode stack is demonstrated to function after triggering post cell formation and through cycling and electrochemical impedance analysis. This work shows that the proposed approach has a negligible impact on the cells’ performance and highlights a new technique for active monitoring of the cell’s in-situ conditions. This research will enable new methods of cells characterization and monitoring for optimum electrochemical and thermal performance while improving system safety

Thermo-electrochemical instrumentation of cylindrical Li-ion cells

The performance evaluation and optimisation of commercially available lithium-ion cells is typically based upon their full cell potential and surface temperature measurements, despite these parameters not being fully representative of the electrochemical processes taking place in the core of the cell or at each electrode. Several methods were devised to obtain the cell core temperature and electrode-specific potential profiles of cylindrical Li-ion cells. Optical fibres with Bragg Gratings were found to produce reliable core temperature data, while their small mechanical profile allowed for low-impact instrumentation method. A pure metallic lithium reference electrode insertion method was identified, avoiding interference with other elements of the cell while ensuring good contact, enabling in-situ observations of the per-electrode electrochemical responses. Our thermo-electrochemical instrumentation technique has enabled us to collect unprecedented cell data, and has subsequently been used in advanced studies exploring the real-world performance limits of commercial cells

In-situ instrumentation for smart energy storage

Lithium-ion technology is an increasing choice for battery powered systems, offering long-lasting, reliable and efficient energy storage. However, significant safety and performance challenges within the technology are still apparent. The current state of the art for monitoring cells performance is typically based on observing full cell voltage and occasional temperature sensor on the skin of a cell. Consequently, it is extremely difficult to track cells’ health within complex, especially high-performance, battery systems. Therefore, a new way of characterising cells’ is required. Here we show the design and manufacturing methods of transforming normal cells into smart systems. The sensor topologies embedded into the cells were electrical temperature, electro-chemical and optical temperature sensors. This enabled in-situ and operando thermal and electrochemical data collection during cells’ real-life operations. In this work, the impact of the sensors upon the cells performance has been shown to be negligible, with over 100 cycles conducted, versus unmodified cells for both pouch and cylindrical formats. This was validated using time and frequency domain analysis. A significant temperature difference was identified between the cell’s core and can temperatures of up to 6 °C during discharge and 3 °C during charge phase. Therefore, this work illustrates the necessity of internal cell temperature measurements for thermal management and safety validation. Lastly, with the aid of the in-situ measurement tools, certain cells can be further optimised without compromising thermal safety limits, while under particular scenarios safety limits can be breached earlier than the external sensors would indicate, showing how paramount in-situ data is to the operational safety

Wireless Communication Test on 868 MHz and 2.4 GHz from inside the 18650 Li-Ion Enclosed Metal Shell

As the RF communication on 18650 Li-ion cell level has not been reported due to its challenges and constrains, in this work, a valid wireless data link is demonstrated in an enclosed empty metal shell at 868 MHz and 2.4 GHz based on the IEEE 802.15.4 standard. The experimental tests are carried out using two generic unturned radiative structures, a wire loop fitted inside a cell shell, and an open terminal sub miniature version A (SMA), subsequently oriented vertically and horizontally relative to the ground plane. Based on signal strength indicator, bit error rate, and packet error rate, the test characterized a payload of 120 bytes at the highest speed of 150 kbps and 250 kbps supported by the IEEE 802.15.4 for the two communication frequencies. A MATLAB simulation is used in parallel to determine the three-dimensional radiative pattern of the two structures, whereas a three-ray model for multipath range propagation is implemented to complete the empirical experiments. It was demonstrated through testing communication of up to 10 m for both operating frequencies, proving the concept of wireless cell communication within short ranges, an essential feature for monitoring the health of each cell inside future electric vehicles (EVs)

DC Power Line Communication (PLC) on 868 MHz and 2.4 GHz Wired RF Transceivers

Efficient management through monitoring of Li-ion batteries is critical to the progress of electro-mobility and energy storage globally, since the technology can be hazardous if pushed beyond its safety boundaries. Battery management systems (BMSs) are being actively improved to reduce size, weight, and cost while increasing their capabilities. Using power line communication, wireless monitoring, or hybrid data links are one of the most advanced research directions today. In this work, we propose the use of radio frequency (RF) transceivers as a communication unit that can deliver both wired and wireless services, through their superior analog and digital signal processing capability compared to PLC technology. To validate our approach computational simulation and empirical evaluation was conducted to examine the possibility of using RF transceivers on a direct current (DC) bus for wired BMS. A key advantage of this study is that it proposes a flexible and tested system for communication across a variety of network scenarios, where wireless data links over disrupted connections may be enabled by using this technology in short-range wired modes. This investigation demonstrates that the IEEE 802.15.4-compliant transceivers with operating frequencies of 868 MHz and 2.4 GHz can establish stable data links on a DC bus via capacitive coupling at high data rates

GaN Transistors’ Radiated Switching Noise Source Evidenced by Hall Sensor Experiments Toward Integration

Wide bandgap Gallium Nitride (GaN) technology promises to deliver the next generation of power transistors capable of high energy density and compact design integration however, without active monitoring high failing rates are recorded due to its instability to design parameter variations. Moreover, the electromagnetic (EM) radiofrequency (RF) emissions due to GaN power switching require extra design resources. Considering the extensive research area dedicated to galvanic isolated magnetic sensors for GaN wafer monolithic integration with usage in power monitoring, this study investigates the conditions that a Hall sensor is required to meet when operating in close proximity of a GaN transistor. Through considerable experimental testing, it was determined that the sensor requires a magnetic field starting from ±1 mT when interfaced with a microcontroller. Additionally, since the GaN transistor's EM RF switching noise was one of the most monitored parameters during the experiments, it was discovered that it is proportional to the transistor's current transfer area whereas its magnitude is due to electrical current required by the load. As a result of these findings, the EM radiated switching noise may apply to all electrical switches and provide a significant advantage when designing for EM compatibility (EMC)

Impact of the Farmington Bay Eutrophication Plume on the Plankton Ecology of Gilbert Bay, Great Salt Lake

Farmington Bay in the Great Salt Lake is hypereutrophic because of extreme nitrogen and phosphorus loading, largely from greater metropolitan Salt Lake City sewage effluents. Although this causes detrimental impacts within the bay, the influence of the outflow of its algal- and nutrient-rich waters into Gilbert Bay is largely unknown. To address this issue, students in the 2010 Aquatic Ecology Practicum course from Utah State University did a 13-km long transect analysis of trophic parameters from the causeway bridge separating the two bays, out into the pelagic zone of Gilbert Bay (Figure 1; Appendix A). On the September 30th date of the transect, flows out of Farmington Bay were low and consequently the plume did not extend far into the lake and we could not detect a plume using MODIS satellite imagery. Nevertheless, the students were able to measure a distinct gradient in a variety of parameters and used water from Gilbert and Farmington Bay in an experiment to assess how Farmington Bay water influences brine shrimp growth. Conductivity profiles indicated that the less dense Farmington Bay water formed an overflow plume that was only 0.2-0.4 m thick