Thermoelectric energy harvester with a cold start of 0.6 °C

This paper presents the electrical and thermal design of a thermoelectric energy harvester power system and its characterisation. The energy harvester is powered by a single Thermoelectric Generator (TEG) of 449 couples connected via a power conditioning circuit to an embedded processor. The aim of the work presented in this paper is to experimentally confirm the lowest ΔT measured across the TEG (ΔTTEG) at which the embedded processor operates to allow for wireless communication. The results show that when a temperature difference of 0.6 °CΔTTEG is applied across the thermoelectric module, an input voltage of 23 mV is generated which is sufficient to activate the energy harvester in approximately 3 minutes. An experimental setup able to accurately maintain and measure very low temperatures is described and the electrical power generated by the TEG at these temperatures is also described. It was found that the energy harvester power system can deliver up to 30 mA of current at 2.2 V in 3ms pulses for over a second. This is sufficient for wireless broadcast, communication and powering of other sensor devices. The successful operation of the wireless harvester at such low temperature gradients offers many new application areas for the system, including those powered by environmental sources and body heat

Evaluation of allelopathic potential of selected plant species on Parthenium hysterophorus

The phytotoxicity of shoot leachates of selected plant species was assessed on germination, and on shootcut and seedling bioassays of Parthenium hysterophorus. Shoot leachates of selected plant species were effective in inhibiting germination of Parthenium seeds, with Azardirachta indica the most effective. Shoot growth was inhibited most, and shoots damaged the most, by leachates of Solanum nigrum

A Warm Proposition : Cake Walk

https://digitalcommons.library.umaine.edu/mmb-ps/2281/thumbnail.jp

A nexus perspective on competing land demands: Wider lessons from a UK policy case study

As nations develop policies for low-carbon transitions, conflicts with existing policies and planning tools are leading to competing demands for land and other resources. This raises fundamental questions over how multiple demands can best be managed. Taking the UK as an empirical example, this paper critiques current policies and practices to explore the interdependencies at the water-energy-food nexus. It considers how current land uses and related policies affect the UK’s resilience to climate change, setting out an agenda for research and practice relevant to stakeholders in land-use management, policy and modelling. Despite recent progress in recognising such nexus challenges, most UK land-related policies and associated science continue to be compartmentalised by both scale and sector and seldom acknowledge nexus interconnections. On a temporal level, the absence of an over-arching strategy leaves inter-generational trade-offs poorly considered. Given the system lock-in and the lengthy policy-making process, it is essential to develop alternative ways of providing dynamic, flexible, practical and scientifically robust decision support for policy-makers. A range of ecosystem services need to be valued and integrated into a resilient land-use strategy, including the introduction of non-monetary, physical-unit constraints on the use of particular services

Synthesis and Optimisation of P3 Substituted Vinyl Sulfone-Based Inhibitors as Anti-Trypanosomal Agents

A series of lysine-based vinyl sulfone peptidomimetics were synthesised and evaluated for anti-trypanosomal activity against bloodstream forms of T. brucei. This focused set of compounds, varying in the P3 position, were accessed in a divergent manner from a common intermediate (ammonium salt 8). Several P3 analogues exhibited sub-micromolar EC50 values, with thiourea 14, urea 15 and amide 21 representing the most potent anti-trypanosomal derivatives of the series. In order to establish an in vitro selectivity index the most active anti-trypanosomal compounds were also assessed for their impact on cell viability and cytotoxity effects in mammalian cells. Encouragingly, all compounds only reduced cellular metabolic activity in mammalian cells to a modest level and little, or no cytotoxicity, was observed with the series

A three-point-based electrical model and its application in a photovoltaic thermal hybrid roof-top system with crossed compound parabolic concentrator

A new coupled optical, thermal and electrical model is presented in this study and applied to a 27 concentrating photovoltaic thermal (PV/T) system for predicting the system performance under 28 various operational conditions. Firstly, a three-point-based electrical model and a method for 29 extracting its five model parameters are developed by using the currents and voltages at the short-, 30 open-circuit and maximum power points provided in usual PV module/panel datasheets. Then, the 31 model and method are validated with the existing six flat-plate PV modules and subsequently are used 32 to predict the hourly electrical performance of the CPV/T roof-top system designed by us under 33 outdoor conditions on four clear days by integrating with a scaling law developed by us. Additionally, 34 transient effect and water temperature on the storage tank are examined. It turned out that the CPV 35 system could operate for 6 hours a day with a peak instant electrical power of 50W/m2 and could 36 generate 0.22kWh/m2 electricity a day in May-July. The error in hourly electrical energy gained 37 between the predictions and observations is in a range of (3.64-8.95)% with the mean of 5.53 % in 38 four days, and the estimated water temperature in the storage tank agrees with the monitored one in 39 range of 0.2-1oC. The proposed methods as well as the electrical models could potentially be applied 40 widely across the solar energy field for the management and operation of the electrical energy 41 production from any CPV/T roof-top system

The Enteropathogenic E. coli Effector EspF Targets and Disrupts the Nucleolus by a Process Regulated by Mitochondrial Dysfunction

The nucleolus is a multifunctional structure within the nucleus of eukaryotic cells and is the primary site of ribosome biogenesis. Almost all viruses target and disrupt the nucleolus—a feature exclusive to this pathogen group. Here, using a combination of bio-imaging, genetic and biochemical analyses, we demonstrate that the enteropathogenic E. coli (EPEC) effector protein EspF specifically targets the nucleolus and disrupts a subset of nucleolar factors. Driven by a defined N-terminal nucleolar targeting domain, EspF causes the complete loss from the nucleolus of nucleolin, the most abundant nucleolar protein. We also show that other bacterial species disrupt the nucleolus, dependent on their ability to deliver effector proteins into the host cell. Moreover, we uncover a novel regulatory mechanism whereby nucleolar targeting by EspF is strictly controlled by EPEC's manipulation of host mitochondria. Collectively, this work reveals that the nucleolus may be a common feature of bacterial pathogenesis and demonstrates that a bacterial pathogen has evolved a highly sophisticated mechanism to enable spatio-temporal control over its virulence proteins