Pengendali Motor Induksi 1 Fasa Dengan Metode PWM Sinusoida Berbasis Mikrokontroler 68HC11

Pada pengendalian motor induksi yang dilakukan secara konvensional tidak diperoleh pengaturan yang kontinyu dan linier, sehingga perlu dilakukan penelitian tentang pengendalian motor induksi dengan teknik inverter. Penelitian ini bertujuan melakukan pengembangan dan evaluasi unjuk kerja pengendalian motor induksi satu fasa dengan metode PWM sunusoida berbasis mikrokontroler. Pengendalian menggunakan rangkaian jembatan inverter jenis PWMVSI (DC-Link inverter) dengan teknik modulasi PWM menggunakan mikrokontroler 68HC11E9, dan diharapkan dapat menggerakkan motor induksi pada kecepatan yang berbeda-beda. Pada penelitian ini digunakan motor induksi satu fasa Z-406, 220 Volt, 50-60 Hz, 125W. Penelitian dimulai dengan pembuatan perangkat keras berupa inverter menggunakan MOSFET sebagai komponen pensaklaran dan diteruskan dengan menyusun rangkaian penggerak inverter satu fasa. Pola sinyal PWM sinusoida dibentuk dengan teknik perhitungan lima modulasi PWM yang berbeda. Dari pola gelombang tersebut dibuat program pembangkit pulsa PWM satu fasa dan perangkat pendukungnya. Selanjutnya dilakukan pengamatan bentuk gelombang PWM keluaran MCU, tegangan, arus keluaran inverter dan mengukur kecepatan putar motor untuk lima indeks modulasi, yaitu (1), (0,81), (0,59), (0,37), dan (0,15). Hasil penelitian menunjukkan bahwa pengaturan kecepatan putar motor induksi untuk frekuensi tetap 50 Hz dengan 5 indeks modulasi berbeda dengan metode PWM sinusoida berbasis mikrokontroler dapat menghasilkan putaran motor yang bervariasi

Supplementary Methods S1 from Small birds, big effects: the little auk (<i>Alle alle</i>) transforms high Arctic ecosystems

In some arctic areas, marine-derived nutrients (MDN) resulting from fish migrations fuel freshwater and terrestrial ecosystems, increasing primary production and biodiversity. Less is known, however, about the role of seabird-MDN in shaping ecosystems. Here, we examine how the most abundant seabird in the North Atlantic, the little auk (<i>Alle alle</i>), alters freshwater and terrestrial ecosystems around the North Water Polynya (NOW) in Greenland. We compare stable isotope ratios (<i>δ</i>¹⁵N and <i>δ</i>¹³C) of freshwater and terrestrial biota, terrestrial vegetation indices and physical–chemical properties, productivity and community structure of fresh waters in catchments with and without little auk colonies. The presence of colonies profoundly alters freshwater and terrestrial ecosystems by providing nutrients and massively enhancing primary production. Based on elevated <i>δ</i>¹⁵N in MDN, we estimate that MDN fuels more than 85% of terrestrial and aquatic biomass in bird influenced systems. Furthermore, by using different proxies of bird impact (colony distance, algal <i>δ</i>¹⁵N) it is possible to identify a gradient in ecosystem response to increasing bird impact. Little auk impact acidifies the freshwater systems, reducing taxonomic richness of macroinvertebrates and truncating food webs. These results demonstrate that the little auk acts as an ecosystem engineer, transforming ecosystems across a vast region of Northwest Greenland

R script Gonzalez Bergonzoni from Small birds, big effects: the little auk (<i>Alle alle</i>) transforms high Arctic ecosystems

In some arctic areas, marine-derived nutrients (MDN) resulting from fish migrations fuel freshwater and terrestrial ecosystems, increasing primary production and biodiversity. Less is known, however, about the role of seabird-MDN in shaping ecosystems. Here, we examine how the most abundant seabird in the North Atlantic, the little auk (<i>Alle alle</i>), alters freshwater and terrestrial ecosystems around the North Water Polynya (NOW) in Greenland. We compare stable isotope ratios (<i>δ</i>¹⁵N and <i>δ</i>¹³C) of freshwater and terrestrial biota, terrestrial vegetation indices and physical–chemical properties, productivity and community structure of fresh waters in catchments with and without little auk colonies. The presence of colonies profoundly alters freshwater and terrestrial ecosystems by providing nutrients and massively enhancing primary production. Based on elevated <i>δ</i>¹⁵N in MDN, we estimate that MDN fuels more than 85% of terrestrial and aquatic biomass in bird influenced systems. Furthermore, by using different proxies of bird impact (colony distance, algal <i>δ</i>¹⁵N) it is possible to identify a gradient in ecosystem response to increasing bird impact. Little auk impact acidifies the freshwater systems, reducing taxonomic richness of macroinvertebrates and truncating food webs. These results demonstrate that the little auk acts as an ecosystem engineer, transforming ecosystems across a vast region of Northwest Greenland

NOW-isotopic summary from Small birds, big effects: the little auk (<i>Alle alle</i>) transforms high Arctic ecosystems

In some arctic areas, marine-derived nutrients (MDN) resulting from fish migrations fuel freshwater and terrestrial ecosystems, increasing primary production and biodiversity. Less is known, however, about the role of seabird-MDN in shaping ecosystems. Here, we examine how the most abundant seabird in the North Atlantic, the little auk (<i>Alle alle</i>), alters freshwater and terrestrial ecosystems around the North Water Polynya (NOW) in Greenland. We compare stable isotope ratios (<i>δ</i>¹⁵N and <i>δ</i>¹³C) of freshwater and terrestrial biota, terrestrial vegetation indices and physical–chemical properties, productivity and community structure of fresh waters in catchments with and without little auk colonies. The presence of colonies profoundly alters freshwater and terrestrial ecosystems by providing nutrients and massively enhancing primary production. Based on elevated <i>δ</i>¹⁵N in MDN, we estimate that MDN fuels more than 85% of terrestrial and aquatic biomass in bird influenced systems. Furthermore, by using different proxies of bird impact (colony distance, algal <i>δ</i>¹⁵N) it is possible to identify a gradient in ecosystem response to increasing bird impact. Little auk impact acidifies the freshwater systems, reducing taxonomic richness of macroinvertebrates and truncating food webs. These results demonstrate that the little auk acts as an ecosystem engineer, transforming ecosystems across a vast region of Northwest Greenland

Dataisotopes from Small birds, big effects: the little auk (<i>Alle alle</i>) transforms high Arctic ecosystems

In some arctic areas, marine-derived nutrients (MDN) resulting from fish migrations fuel freshwater and terrestrial ecosystems, increasing primary production and biodiversity. Less is known, however, about the role of seabird-MDN in shaping ecosystems. Here, we examine how the most abundant seabird in the North Atlantic, the little auk (<i>Alle alle</i>), alters freshwater and terrestrial ecosystems around the North Water Polynya (NOW) in Greenland. We compare stable isotope ratios (<i>δ</i>¹⁵N and <i>δ</i>¹³C) of freshwater and terrestrial biota, terrestrial vegetation indices and physical–chemical properties, productivity and community structure of fresh waters in catchments with and without little auk colonies. The presence of colonies profoundly alters freshwater and terrestrial ecosystems by providing nutrients and massively enhancing primary production. Based on elevated <i>δ</i>¹⁵N in MDN, we estimate that MDN fuels more than 85% of terrestrial and aquatic biomass in bird influenced systems. Furthermore, by using different proxies of bird impact (colony distance, algal <i>δ</i>¹⁵N) it is possible to identify a gradient in ecosystem response to increasing bird impact. Little auk impact acidifies the freshwater systems, reducing taxonomic richness of macroinvertebrates and truncating food webs. These results demonstrate that the little auk acts as an ecosystem engineer, transforming ecosystems across a vast region of Northwest Greenland

Appendix A. Groups of plant macrofossil remains identified in sediment cores of Lake Lading or Lake Søbygaard.

Groups of plant macrofossil remains identified in sediment cores of Lake Lading or Lake Søbygaard

Appendix B. PCA species scores for Lake Lading and Lake Søbygaard (as shown in Fig. 3).

PCA species scores for Lake Lading and Lake Søbygaard (as shown in Fig. 3)

Nutrients and saltwater exchange as drivers of environmental change in a Danish brackish coastal lake over the past 100 years

Many northwest European lake systems are suffering from the effects of eutrophication due to continued loading and/or poor, ineffective management strategies. Coastal brackish lakes are particularly difficult to manage due to complex nitrogen, phosphorus, and salinity dynamics that may exert varying influence on lake biological communities, but long-term data on how these important and often biodiverse systems respond to change are rare. In this study, palaeolimnological data (including sedimentary parameters, diatoms, and plant macrofossils) and environmental monitoring data (for the last ~40 years) have been used to assess environmental change over the last 100 years in Kilen, a brackish lake in northwest Jutland, Denmark. Kilen has been regularly monitored for salinity (since 1972), TP (from 1975), TN (from 1976), and since 1989 for biological data (phytoplankton, zooplankton, and macrophytes), which allows a robust comparison of contemporary and paleolimnological data at high temporal resolution. The palaeolimnological data indicate that the lake has been nutrient rich for the last 100 years, with eutrophication peaking from the mid-1980s to the late 1990s. Reduced nutrient concentrations have occurred since the late 1990s, though this is not reflected in the sediment core diatom assemblage, highlighting that caution must be taken when using quantitative data from biological transfer functions in paleolimnology. Lake recovery over the last 20 years has been driven by a reduction in TN and TP loading from the catchment and shows improvements in the lake water clarity and, recently, in macrophyte cover. Reduced salinity after 2004 has also changed the composition of the dominant macrophyte community within the lake. The low N:P ratio indicates that in summer, the lake is predominately N-limited, likely explaining why previous management, mainly focusing on TP reduction measures, had a modest effect on the water quality of the lake. Despite a slight recovery, the lake is still nutrient-rich, and future management of this system must continue to reduce the nutrient loads of both TN and TP to ensure sustained recovery. This study provides an exceptional opportunity to validate the palaeolimnological record with monitoring data and demonstrates the power of using this combined approach in understanding environmental change in these key aquatic ecosystems

Reconstructing the salinity and environment of the Limfjord and Vejlerne Nature Reserve, Denmark, using a diatom model for brackish lakes and fjords

Diatoms in surface sediments from a data set of 27 brackish lakes and nine fjords in Jutland, Denmark (range 0.2 – 31 g·L–1 total dissolved solids (TDS)), were analysed using multivariate methods to determine response to measured parameters (depth, total phosphorus (TP), total nitrogen (TN), TN/TP, salinity, water body type). Water body type, salinity, depth and TP together explained 25.3% of the variation in the diatom data and were all independently significant predictors. A diatom–salinity model (r2 jack = 0.887, root mean square error of prediction = 0.246 log salinity, g·L–1) was developed from the 36 sample training set and applied to fossil diatom assemblages in three sediment cores from the east Vejlerne wetland, Denmark, a nature reserve created after the damming of an embayment of the polyhaline Limfjord (~26 g·L–1 TDS) in the late 19th century. The diatom-inferred salinity reconstructions reflect the known salinity history of the Limfjord and the freshwater–subsaline Vejlerne lakes, and appear sensitive to documented North Sea storms in the 16th and 17th centuries, which had major impacts on the brackish Limfjord herring fishery. Diatom–salinity models may be useful tools in long-term studies of coastal and estuarine areas to test hypotheses concerning aquatic resources and ecological, hydrographic, and cultural change

Supplement 1. Data from the 83 South American lakes sampled.

<h2>File List</h2><blockquote> <p><a href="South_American_Lakes_data.txt">South_American_Lakes_data.txt</a> -- data file </p> </blockquote><h2>Description</h2><blockquote> <p>The "South American Lakes data file" contains data on 83 shallow lakes sampled in South America between November 2004 and March 2006. The following data is presented: X coordinate (Decimal degrees); Y coordinate (Decimal degrees); name (Name of the lake. Not all lakes have a name and some lakes are referred to by multiple names); climate zone (The lakes were grouped in five different categories based on the prevailing climate characteristics following the Köppen climate system (1936) digitized by Leemans and Cramer (1991): tropicali, tropical, subtropical, maritime temperate and tundra zone. The Köppen classification is based on monthly rainfall and temperature. Tropicali is an isothermal subzone in the tropics, which has a smaller annual temperature range than the tropical zone, source:<br> <a href="http://www.fao.org/WAICENT/FAOINFO/SUSTDEV/EIdirect/climate/EIsp0002.htm">http://www.fao.org/WAICENT/FAOINFO/SUSTDEV/EIdirect/climate/EIsp0002.htm</a>); average air temperature in warmest month (Celcius, source: M. New, D. Lister, M. Hulme, and I. Makin. 2002. A high-resolution data set of surface climate over global land areas. Climate Research 21. The complete paper can be freely downloaded via:<br> <a href="http://www.cru.uea.ac.uk/cru/data/tmc.htm">http://www.cru.uea.ac.uk/cru/data/tmc.htm</a>); average air temperature in coldest month (Celcius, source: M. New, D. Lister, M. Hulme, and I. Makin. 2002: A high-resolution data set of surface climate over global land areas. Climate Research 21. The complete paper can be freely downloaded via:<br> <a href="http://www.cru.uea.ac.uk/cru/data/tmc.htm">http://www.cru.uea.ac.uk/cru/data/tmc.htm</a>); soil type (Source: SOTERLAC "Soil and terrain database for Latin America and the Caribbean ", FAO: Land and Water Digital Media Series #5, scale: 1:5 million scale. Type of top soil and descriptions of the different types can be found at:<br> <a href="http://www.fao.org/AG/agl/agll/key2soil.stm">http://www.fao.org/AG/agl/agll/key2soil.stm</a>); lake area (m², determined using landsat Orthorectified Landsat Thematic Mapper Mosaics of the year 2000. If image was cloudy images of 1990 were used. In rare cases when image deviated much from area observed in the field, all waypoints measured in the field were plotted on top of the image and a "best matching" polygon was drawn around it, of which the area was determined); average depth (Meter, the average depth of the lake was determined using depth measurements from 20 random points and 20 points along transects perpendicular to the longest axis of the lake); altitude (Meter above sea level, based on DEM from gtopo30, converted to an Arcview grid using the procedure published on herpnet.org GTOPT_DEM); conductivity (µS/cm); Total nitrogen (mg/L); Total phosphorus (mg/L); chlorophyll <i>a</i> (µg/L)</p> -- TABLE: Please see in attached file. -- </blockquote