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This paper presents a detailed analysis of the two most well-known hill-climbing maximum power point tracking (MPPT) algorithms: the perturb-and-observe (P&O) and incremental conductance (INC). The purpose of the analysis is to clarify some common misconceptions in the literature regarding these two trackers, therefore helping the selection process for a suitable MPPT for both researchers and industry. The two methods are thoroughly analyzed both from a mathematical and practical implementation point of view. Their mathematical analysis reveals that there is no difference between the two. This has been confirmed by experimental tests according to the EN 50530 standard, resulting in a deviation between their efficiencies of 0.13% in dynamic and as low as 0.02% under static conditions. The results show that despite the common opinion in the literature, the P&O and INC are equivalent.

Current economic instruments aimed at climate change mitigation focus mainly on CO(2) emissions, but efficient climate mitigation needs to focus on other greenhouse gases as well as CO(2). This study investigates the distributional effects of climate change taxes on households belonging to different income and lifestyle groups; and it compares the effects of a CO(2) tax with a multiple GHG tax in the UK in terms of cost efficiency and distributional effects. Results show that a multi GHG tax is more efficient than a CO(2) tax due to lower marginal abatement costs, and that both taxes are regressive, with lower income households paying a relatively larger share of their income for the taxes than higher income households. A shift from a CO(2) tax to a GHG tax will reduce and shift the tax burden between consumption categories such as from energy-intensive products to food products. Consumers have different abilities to respond to the tax and change their behavior due to their own socio-economic attributes as well as the physical environment such as the age of the housing stock, location, and the availability of infrastructure. The housing-related carbon emissions are the largest component of the CO(2) tax payments for low income groups and arguments could be made for compensation of income losses and reduction of fuel poverty through further government intervention.

We analysed the effect of applying Dutch thermal efficiency standards of residential dwellings, conversion efficiency, appliance fuel mixes and appliance ownership rates, to the UK residential sector. We found that although aggregate energy consumption does not change significantly, pollution emissions are reduced significantly. Thus, the primary difference between housing and appliance stocks in the two regions is in terms of fuel mixes. However, improved thermal efficiency does allow for increased dwelling warmth without increasing emissions. Adapting Dutch standards in the UK would lead to a one-time improvement of the environmental situation, after which the trend is continued.

Nest site selection is a critical behaviour, particularly in species with no parental care, as it can greatly impact offspring survival. Marine turtles depend on sandy beaches to nest, where they select from a range of microhabitats that may differently affect hatchling survival and phenotype. Here we describe the degree of nest site selection at one of the largest green turtle rookeries globally, in Guinea-Bissau, West Africa, and how this impacts offspring. In 2013 and 2014 we recorded the spatial distribution of 1559 nests, and monitored 657 females during oviposition, to assess population and individual preferences on nesting site. Overall, females tended to nest close to the vegetation, at a preferred elevation of 4.8–5.0 m, which was above the highest spring tide (4.7 m), enhancing clutch survival. Individuals displayed high repeatability in nesting microhabitat type (open sand, forest border and forest), distance along the beach, distance to the vegetation and elevation, which may result from this behaviour having a genetic basis or from fine-scale nest site philopatry. Hatchlings from cooler nests were larger, potentially dispersing faster and more able to evade predators, while smaller hatchlings, from warmer nests, retained more energetic reserves (residual yolk), which may also be advantageous for initial dispersal, particularly if food is scarce. Thus, individual preferences in nest site selection led to trade-offs in offspring phenotype, but overall, most nesting females selected sites that increased offspring survival, suggesting that nest site selection is an adaptive trait that has been under selection. As under future climate change scenarios females nesting in upper shaded areas should have higher fitness, individual consistency in nesting microhabitat provides opportunity for natural selection to occur.

The growing interest in forest biomass has made chipping increasingly popular all across Europe. Many operators have equipped for the purpose, but the large variety of working conditions found in the European forests makes it difficult to correctly estimate the productivity of each specific operation, leading to uncertainty in crucial decisions, such as: operation scheduling, price setting, machinery selection and acquisition. In 2001, the Italian National Council for Research (CNR) and the University of California (UC) developed a spreadsheet freeware capable of returning reliable estimates of chipping productivity and cost, on the basis of user-defined input data. The model is still available from the CNR website and is the object of frequent downloading and inquiries. Such model contains a set of predictive equations derived from the results of 102 field trials, conducted with 30 different machines, under a range of working conditions. In order to facilitate comparison with other estimates and to achieve methodological transparency, the equations are assembled into a simple Microsoft Excel workbook, and the costs are calculated with standard costing methods currently used in Forest and Agricultural Engineering. Since then CNR has continued to work on the subject, with the goal of updating and refining the model. Such work has included 45 validation tests and a separate study on the delay (idle) time typical for different chipping operation layouts. The study was concluded in 2009 and confirms that the model developed by CNR can provide reliable estimates of chipper productivity under a range of operational conditions. Authors believe that such a model can assist European foresters in keeping ahead with the growing biomass sector, thus helping them to seize an important business opportunity.

Large-scale photovoltaic (PV) plants enable the reduction of the PV plant cost per watt of nominal power that is installed. In this paper, a new method is presented for the calculation of the optimal configuration of large PV plants, such that the levelized cost of the generated electricity (LCOE) is minimized. The proposed design optimization process is performed by considering the impact of the number of components, as well as their type and arrangement within the installation field, on the tradeoff between the lifetime cost and the corresponding energy production of the PV plant. The high-accuracy feature of the energy production calculations that are performed by the proposed design tool has been validated using experimental operational data of an existing PV plant. The design results demonstrate that using the proposed optimization method allows a reduction of the cost of the energy that is generated by the large-scale PV plant, thus enabling the maximization of the economic benefit that is obtained during the operational lifetime period of the PV system.

Enhanced or reduced pCO(2) (partial pressure of CO2) may affect the photosynthetic performance of marine microalgae since changes in pCO(2) can influence the activity of carbon concentrating mechanisms, modulate cellular RuBisCO levels or alter carbon uptake efficiency. In the present study we compared the photophysiology of the Antarctic diatom Chaetoceros brevis at two pCO(2) extremes: 750 ppmv (2x ambient) and 190 ppmv (0.5x ambient) CO2. Cultures were acclimated to four irradiance regimes: two regimes simulating deep or shallow vertical mixing, and two regimes mimicking limiting and saturating stable water column conditions. Then, growth rate, pigmentation, RuBisCO large subunit expression. RuBisCO activity, photosynthesis vs irradiance curves, effective quantum yield of PSII (F-v/F-m), and POC were measured. The four irradiance regimes induced a suite of photophysiological responses, ranging from low light acclimation to efficient photoprotection. Growth was reduced under the low constant and the deep mixing regime, compared to the shallow mixing and the stable saturating regime. Low stable irradiance resulted in higher light harvesting pigment concentrations, lower RuBisCO activity and a lower light saturation point (E-k) compared to the other irradiance regimes. Highest RuBisCO activity as well as P-max levels was measured in the shallow mixing regime, which received the highest total daily light dose. Photoprotection by xanthophyll cycling was observed under all irradiance regimes except the low stable irradiance regime, and xanthophyll cycle pool sizes were higher under the dynamic irradiance regimes. For the fluctuating irradiance regimes. E-v/E-m was hardly affected by previous excess irradiance exposure, suggesting minimal PSII damage. No significant differences between the two pCO(2) levels were found, with respect to growth, pigment content and composition, photosynthesis, photoprotection and RuBisCO activity, for all four irradiance regimes. Thus, within the range tested, pCO(2) does not significantly affect the photophysiological performance of C. brevis. (C) 2011 Elsevier B.V. All rights reserved.

While park-people conflicts have received worldwide attention, the extent of illegal resource extraction and the relationship with communities' livelihoods has gained little attention in the literature. Thus this paper investigates the impact of socio-economic factors involved in illegal fuel wood and fodder extraction at Bardia National Park in Nepal. Household questionnaires, key-informant interviews and focus groups were conducted to identify different plant species used by households and explore the causes and mode of resource extraction in three buffer zone villages in the park. Altogether 50 different plants were identified by villagers that were used regularly for different livelihood purposes. Almost half of the respondents met their needs by illegally and regularly extracting resources from the park. Incentive schemes in the form of development projects were important but not sufficient in meeting the basic needs of households' especially for such daily items such as fuel wood and fodder. The results described in this paper showed that proximity and access to resources either in the national park, the buffer zone community forest or the government forest, and impact on the livelihoods significantly influenced the likelihood of illegal resource extraction activities. Villages that differed in terms of their location to the resource base, the provision of alternative resources and influence of these on their livelihoods showed significant differences in terms of their patterns of resource extraction and use of these resources. As resource use options, resource interest, and resource extraction patterns were different between villages and dependent on circumstances specific to villages, site-specific management strategies were necessary and more influential than the enforcement of 'one-size fits all' policies. It is suggested that park management plans should be flexible and adaptive enough to meet site-specific contexts and to endear wider support from local communities.