94 research outputs found

    The Design and Development of the SMEX-Lite Power System

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    This paper describes the design and development of a 250W orbit average electrical power system electronic Power Node and software for use in Low Earth Orbit missions. The mass of the Power Node is 3.6 Kg (8 lb.). The dimensions of the Power Node are 30cm x 26cm x 7.9cm (11 in. x 10.25 in x 3.1 in.) The design was realized using software, Field Programmable Gate Array (FPGA) digital logic and surface mount technology. The design is generic enough to reduce the non-recurring engineering for different mission configurations. The Power Node charges one to five, low cost, 22-cell 4 AH D-cell battery packs independently. The battery charging algorithms are executed in the power software to reduce the mass and size of the power electronic. The Power Node implements a peak-power tracking algorithm using an innovative hardware/software approach. The power software task is hosted on the spacecraft processor. The power software task generates a MIL-STD-1553 command packet to update the Power Node control settings. The settings for the battery voltage and current limits, as well as minimum solar array voltage used to implement peak power tracking are contained in this packet. Several advanced topologies are used in the Power Node. These include synchronous rectification in the bus regulators, average current control in the battery chargers and quasi-resonant converters for the Field Effect Transistor (FET) transistor drive electronics. Lastly, the main bus regulator uses a feed-forward topology with the PWM implemented in an FPGA

    A Robust Waveguide Millimeter-Wave Noise Source

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    This paper presents the design, fabrication, and characterization of a millimeter-wave noise source for the 160- 210 GHz frequency range. The noise source has been implemented in an E-split-block waveguide package and the internal circuitry was developed on a quartz substrate. The measured excess noise ratio at 200 GHz is 9.6 dB

    Warming and elevated CO2 promote rapid incorporation and degradation of plant-derived organic matter in an ombrotrophic peatland

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    Rising temperatures have the potential to directly affect carbon cycling in peatlands by enhancing organic matter (OM) decomposition, contributing to the release of CO2 and CH4 to the atmosphere. In turn, increasing atmospheric CO2 concentration may stimulate photosynthesis, potentially increasing plant litter inputs belowground and transferring carbon from the atmosphere into terrestrial ecosystems. Key questions remain about the magnitude and rate of these interacting and opposing environmental change drivers. Here, we assess the incorporation and degradation of plant- and microbe-derived OM in an ombrotrophic peatland after 4 years of whole-ecosystem warming (+0, +2.25, +4.5, +6.75 and +9°C) and two years of elevated CO2 manipulation (500 ppm above ambient). We show that OM molecular composition was substantially altered in the aerobic acrotelm, highlighting the sensitivity of acrotelm carbon to rising temperatures and atmospheric CO2 concentration. While warming accelerated OM decomposition under ambient CO2, new carbon incorporation into peat increased in warming × elevated CO2 treatments for both plant- and microbe-derived OM. Using the isotopic signature of the applied CO2 enrichment as a label for recently photosynthesized OM, our data demonstrate that new plant inputs have been rapidly incorporated into peat carbon. Our results suggest that under current hydrological conditions, rising temperatures and atmospheric CO2 levels will likely offset each other in boreal peatlands

    Penyelesaian Kasus Sengketa Pencemaraan Lingkungan Melalui Peradilan Perdata

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    Abstrak.              Penyelesaian kasus sengketa pencemaran lingkungan melalui peradilan perdata.penyelesaian yang dilakukan melalui dari litigasi,setelah sebelumnya melakukan penyelsaian sengketa lingkungan melalui non litigasi.tujuan dari membuat jurnal dari judul tersebut adalh untuk meningkatkan kesadaraan masyarakat sekitar untuk bisa mengetahui bahwa kerrugian yang kita alami dari terjadinya menurunnya suatu kualitas lingkungan yang sehingga bisa berdampak terhadap kita nantinya bisa di proses secara hukum melalui instrument perdata.metode pendekatan yang dilakukan oleh kelompok pkm menggunankan presentasi,tanya jawab dan diskusi untk materi bersangkutan.dari kegiatan yang telah dilaksankan masih banyaknya audiens yang tidak mengetahui tentang adanya hukum yang melindungi lingkungan dair pencemaran dan kerusakan lingkungan.hasil dari kegiatanpun berjalan dengan baik dan antusias sehingga dimana menimbulkan interaksi dua arah antar pemateri dengan audiens
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