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Metal casings shield the cathodic protection current and detection signals of buried metal pipelines, making the corrosion protection and detection technology of pipelines at the casing one of the challenges for safe operation and integrity evaluation of pipelines. This paper uses the primary current distribution physics interface in the COMSOL Multiphysic simulation software to study the effects of the coating quality of the casing and pipeline, the installation of sacrificial anodes in the casing, the conductivity of the electrolyte, and defects in the pipeline coating in the casing on the pipeline potential. The influence of distribution. The results show that: The coating quality of the outer surface of the casing and the pipe inside the casing has a great influence on the cathodic protection potential of the pipeline. The better the coating quality, the more negative the cathodic protection potential is, and the less cathodic protection current required by the pipeline, so the power consumption of the forced current law is reduced, and the service life of the sacrificial anode is longer. Installing sacrificial anodes in the casing has a positive effect on the cathodic protection of this special pipe section. The conductivity of the electrolyte in the casing has a certain impact on the cathodic protection potential of the pipeline. When the conductivity of the internal electrolyte is greater, the protective potential of the pipeline becomes more negative. However, impurities such as soil, groundwater, and silt make the pipeline more susceptible to corrosion, so keeping the annular space relatively dry is an important prerequisite for anti-corrosion. When there is a coating defect on the inner and outer pipes of the casing, the potential at the damaged point will have a potential peak. The larger the potential peak difference, the more serious the coating defect is.

Nowadays, the use of a linear anode in an impressed current cathodic protection system is one of the most interesting technical solutions to guarantee the corrosion protection of short pipe in common and even in congested area. The determination of the minimum distance between linear anode and pipe, and the effective parameters to reach the protection potential, can be studied at two different levels. First, the use of a primary current distribution analysis allows finding the proper distance based on the geometry, physical environmental parameters, and maximum allowable potential difference of two sides of the pipe. The second level is to consider the polarizability of the cathode, then to apply the so-called secondary current distribution analysis. The primary current distribution shows that the linear anode-to-pipe distance is mainly affected by soil resistivity and pipe diameter. Secondary current distribution analysis emphasizes that the proper minimum distance is influenced by the polarization of the cathode, i.e., the overvoltages of the two cathodic reactions of oxygen reduction and hydrogen evolution. In both approaches, soil resistivity has a predominant effect on potential distribution on the pipe surface.

Traditional macro and micro-electroporation devices utilize facing electrodes, which generate electric fields inversely proportional to their separation distance. Although the separation distances in micro-electroporation devices are significantly smaller than those in macro-electroporation devices, they are limited by cell size. Because of this, significant potential differences are required to induce electroporation. These potential differences are often large enough to cause water electrolysis, resulting in electrode depletion and bubble formation, both of which adversely affect the electroporation process. Here, we present a theoretical study of a novel micro-electroporation channel composed of an electrolyte flowing over a series of adjacent electrodes separated by infinitesimally small insulators. Application of a small, non-electrolysis inducing potential difference between the adjacent electrodes results in radially-varying electric fields that emanate from these insulators, causing cells flowing through the channel to experience a pulsed electric field. This eliminates the need for a pulse generator, making a minimal power source (such as a battery) the only electrical equipment that is needed. A non-dimensional primary current distribution model of the novel micro-electroporation channel shows that decreasing the channel height results in an exponential increase in the electric field magnitude, and that cells experience exponentially greater electric field magnitudes the closer they are to the channel walls. Finally, dimensional primary current distribution models of two potential applications, water sterilization and cell transfection, demonstrate the practical feasibility of the novel micro-electroporation channel.

A new solution for the computation of a current distribution with a moving boundary is presented. The numerical scheme is based on the capabilities of two commercial codes FEMLAB 2.3 and MATLAB 6.1. First a computation is carried out with FEMLAB which provides the electrical potential distribution at the initial time. The FEM problem and its initial solution are then saved as a MATLAB program. The MATLAB code containing the whole – draw, mesh, solve, plot – sequence is then modified to automate the iterative process. A movie is finally made from the successive solutions stored as JPEG pictures. A metal deposition process is presented as a simple test but difficult benchmark. This method is validated and can be easily extended to much more complex coupled electrochemical processes.

Aim: Primary forests have high conservation value but are rare in Europe due to historic land use. Yet many primary forest patches remain unmapped, and it is unclear to what extent they are effectively protected. Our aim was to (1) compile the most comprehensive European-scale map of currently known primary forests, (2) analyse the spatial determinants characterizing their location and (3) locate areas where so far unmapped primary forests likely occur. Location: Europe. Methods: We aggregated data from a literature review, online questionnaires and 32 datasets of primary forests. We used boosted regression trees to explore which biophysical, socio-economic and forest-related variables explain the current distribution of primary forests. Finally, we predicted and mapped the relative likelihood of primary forest occurrence at a 1-km resolution across Europe. Results: Data on primary forests were frequently incomplete or inconsistent among countries. Known primary forests covered 1.4 Mha in 32 countries (0.7% of Europe's forest area). Most of these forests were protected (89%), but only 46% of them strictly. Primary forests mostly occurred in mountain and boreal areas and were unevenly distributed across countries, biogeographical regions and forest types. Unmapped primary forests likely occur in the least accessible and populated areas, where forests cover a greater share of land, but wood demand historically has been low. Main conclusions: Despite their outstanding conservation value, primary forests are rare and their current distribution is the result of centuries of land use and forest management. The conservation outlook for primary forests is uncertain as many are not strictly protected and most are small and fragmented, making them prone to extinction debt and human disturbance. Predicting where unmapped primary forests likely occur could guide conservation efforts, especially in Eastern Europe where large areas of primary forest still exist but are being lost at an alarming pace.

The increasing demand for renewable energy is projected to result in a 40-fold increase in offshore wind electricity in the European Union by 2030. Despite a great number of local impact studies for selected marine populations, the regional ecosystem impacts of offshore wind farm (OWF) structures are not yet well assessed nor understood. Our study investigates whether the accumulation of epifauna, dominated by the filter feeder Mytilus edulis (blue mussel), on turbine structures affects pelagic primary productivity and ecosystem functioning in the southern North Sea. We estimate the anthropogenically increased potential distribution based on the current projections of turbine locations and reported patterns of M. edulis settlement. This distribution is integrated through the Modular Coupling System for Shelves and Coasts to state-of-the-art hydrodynamic and ecosystem models. Our simulations reveal non-negligible potential changes in regional annual primary productivity of up to 8% within the OWF area, and induced maximal increases of the same magnitude in daily productivity also far from the wind farms. Our setup and modular coupling are effective tools for system scale studies of other environmental changes arising from large-scale offshore wind farming such as ocean physics and distributions of pelagic top predators.

With the rapid development of power electronics technology, microgrid (MG) concept has been widely accepted in the field of electrical engineering. Due to the advantages of direct current (DC) distribution systems such as reduced losses and easy integration with energy storage resources, DC MGs have drawn increasing attentions nowadays. With the increase of distributed generation, a DC MG consisting of multiple sources is a hot research topic. The challenge in such a multi-source DC MG is to provide voltage support and good power sharing performance. As the control strategy plays an important role in ensuring MG’s power quality and efficiency, a comprehensive review of the state-of-art control approaches in DC MGs is necessary. This paper provides an overview of the primary and secondary control methods under the hierarchical control architecture for DC MGs. Specifically, inner loop and droop control approaches in primary control are reviewed. Centralized, distributed, and decentralized approach based secondary control is discussed in details. Key findings and future trends are also presented at last.

High primary productivity in the equatorial Atlantic and Pacific oceans is one of the key features of tropical ocean biogeochemistry and fuels a substantial flux of particulate matter towards the abyssal ocean. How biological processes and equatorial current dynamics shape the particle size distribution and flux, however, is poorly understood. Here we use high-resolution size-resolved particle imaging and Acoustic Doppler Current Profiler data to assess these influences in equatorial oceans. We find an increase in particle abundance and flux at depths of 300 to 600 m at the Atlantic and Pacific equator, a depth range to which zooplankton and nekton migrate vertically in a daily cycle. We attribute this particle maximum to faecal pellet production by these organisms. At depths of 1,000 to 4,000 m, we find that the particulate organic carbon flux is up to three times greater in the equatorial belt (1° S–1° N) than in off-equatorial regions. At 3,000 m, the flux is dominated by small particles less than 0.53 mm in diameter. The dominance of small particles seems to be caused by enhanced active and passive particle export in this region, as well as by the focusing of particles by deep eastward jets found at 2° N and 2° S. We thus suggest that zooplankton movements and ocean currents modulate the transfer of particulate carbon from the surface to the deep ocean. Vertical migration of organisms and deep currents control the transport and characteristics of particles at the equator, according to an analysis of current and particle measurements. Particles fluxes are an important part of the ocean carbon cycle.

Cutaneous leishmaniasis (CL) is a vector-borne parasitic diseases of public health importance that is prevalent in the West Bank but not in the Gaza Strip. The disease caused by parasitic protozoans from the genus Leishmania and it is transmitted by infected phlebotomine sand flies. The aim of our study is to investigate the eco-epidemiological parameters and spatiotemporal projections of CL in Palestine over a 30-years period from 1990 through 2020 and to explore future projections until 2060. This long-term descriptive epidemiological study includes investigation of demographic characteristics of reported patients by the Palestinian Ministry of Health (PMoH). Moreover, we explored spatiotemporal distribution of CL including future projection based on climate change scenarios. The number of CL patients reported during this period was 5855 cases, and the average annual incidence rate (AAIR) was 18.5 cases/105 population. The male to female ratio was 1.25:1. Patients-age ranged from 2 months to 89 years (mean = 22.5, std 18.67, and the median was 18 years). More than 65% of the cases came from three governates in the West Bank; Jenin 29% (1617 cases), Jericho 25% (1403), and Tubas 12% (658) with no cases reported in the Gaza Strip. Seasonal occurrence of CL starts to increase in December and peaked during March and April of the following year. Current distribution of CL indicate that Jericho, Tubas, Jenin and Nablus have the most suitable climatic settings for the sandfly vectors. Future projections until 2060 suggest an increasing incidence from northwest of Jenin down to the southwest of Ramallah, disappearance of the foci in Jericho and Tubas throughout the Jordan Vally, and possible emergence of new foci in Gaza Strip. The future projection of CL in Palestine until 2060 show a tendency of increasing incidence in the north western parts of the West Bank, disappearance from Jericho and Tubas throughout the Jordan Vally, and emergence of new CL endemic foci in the Gaza Strip. These results should be considered to implement effective control and surveillance systems to counteract spatial expansion of CL vectors.

Nutrient amendment experiments at the boundary of the South Atlantic gyre reveal extensive regions in which nitrogen and iron are co-limiting, with other micronutrients also approaching co-deficiency; such limitations potentially increase phytoplankton community diversity. Moderating marine micronutrients Whether micronutrient co-limitation is pervasive in the ocean and whether it affects phytoplankton growth and productivity is poorly understood. Through a series of large-scale nutrient amendment experiments at the eastern boundary of the South Atlantic gyre, Thomas Browning and colleagues report extensive regions in which nitrogen and iron are co-limiting, with near co-deficiency of the trace metal cobalt and vitamin B 12 . These findings suggest that nitrogen–iron co-limitation is pervasive in the ocean and potentially increases phytoplankton community diversity. Nutrient limitation of oceanic primary production exerts a fundamental control on marine food webs and the flux of carbon into the deep ocean 1 . The extensive boundaries of the oligotrophic sub-tropical gyres collectively define the most extreme transition in ocean productivity, but little is known about nutrient limitation in these zones 1 , 2 , 3 , 4 . Here we present the results of full-factorial nutrient amendment experiments conducted at the eastern boundary of the South Atlantic gyre. We find extensive regions in which the addition of nitrogen or iron individually resulted in no significant phytoplankton growth over 48 hours. However, the addition of both nitrogen and iron increased concentrations of chlorophyll a by up to approximately 40-fold, led to diatom proliferation, and reduced community diversity. Once nitrogen–iron co-limitation had been alleviated, the addition of cobalt or cobalt-containing vitamin B 12 could further enhance chlorophyll a yields by up to threefold. Our results suggest that nitrogen–iron co-limitation is pervasive in the ocean, with other micronutrients also approaching co-deficiency. Such multi-nutrient limitations potentially increase phytoplankton community diversity.