Applications for dc-to-dc converters include dc power supplies for electronic systems, hand-held electronics, portable electronics, electric vehicles, battery chargers , , systems for the utilization of fuel cell -, solar -, and wind energy , which incorporate super-capacitors , smart grids and distributed generation -, electronicballast , energy harvesting , power factor correction, and dc motor drives. Additionally, these converters form the basic building blocks for other power converter types, plus interleaved or multiphase converters -, bidirectional dc-to-dc converters - multiple input converters , cascaded output converters ,  and high voltage supplies. Similar to basic dc-to-dc converter analysis , with snubbers , converters can be controlled in a voltage mode or a current mode , .
The single stage, singleswitch high power factor electronicballast, integrates and resonant inverter stage. The active power switch of the proposed electronicballast is excited by the driving signal . The duty cycle of the driving signal is d. The circuit operation can be divided into two modes in accordance with the conducting power switch within one high-frequency cycle.
Most high-frequency electronic ballasts have load resonant inverters that provide ignition voltage and a stable lamp current with a low crest factor for fluorescent lamps. Furthermore, load resonant inverters can operate at very high switching frequencies and have low switching losses and electromagnetic interference (EMI). To enhance the efficiency of high-frequency electronic ballasts, many soft-switching technologies have been developed [11-15]. The class-E zero voltage- switching (ZVS) resonant inverters have the highest efficiency of all existing resonant inverters. The class-E ZVS resonant inverter has a single-ended structure and, thus, is unlike class-D ZVS inverters, which have a double- ended output and, thus requires two separate gate trigger signals and an upper trigger signal that has an isolated circuit. Additionally, the trigger circuit in the class- E topology, which has a single end, is simple. Consequently, the class-E ZVS resonant inverter has recently become common in switchmode power applications. The use of a class-E ZVS resonant inverter as a fluorescent lamp ballast has such advantages as few components, low cost and high power density. These characteristics, combined with the fact that the class-E ZVS resonant inverter has only one active power switch, result in electronicballast with a very simple structure, low switching losses, small volume and light weight. Additionally, as commutations in the active power switch of the class-E resonant inverter are performed at zero voltage, electronicballast switching losses are extremely low, resulting in very high efficiency.
The beginning of this mode, the switch S turns off and the diodes D1 and D2 start conducting. By conduction of D1, voltage across the switch is clamped to C01. The voltage Vo is applied to the inductor Llk inversely and its current decreases until reaches zero. In this way, the leakage energy is absorbed and voltage spikes across the switch are eliminated. The time duration of this mode is too short when switch is turn off
The design of the circuit is fairly simple. The main power line to the room is diverted through the circuit before powering the electrical devices in the room. A pair of Light Dependent Resistors keep track of the number of people in the room and their output signal is fed to the Arduino board through Serial Analog input channels. The Arduino board also controls the relay switch which cuts off power to the room accordingly. A Liquid Crystal Display interfaced with the Arduino Board dynamically displays the number of people in the room.
to be imaginarily extended. The row mosaic consists of double cones whose partitions are not as perpendicular to each other as in the square mosaic, and spacing between single cones is often not as regular as in the square mosaic either (Beaudet et al., 1997; Novales Flamarique, 2001; Novales Flamarique, 2002). In many areas of the salmonid retina, these two mosaics coexist and, at least in the retina of the juvenile (~10·g in weight), the same cones can align in a row at the double cone ellipsoid level and in a square at the nuclear level (Novales Flamarique, 2001). Salmonid fishes hatch as yolk sac alevins and proceed to absorb their yolk sacs over a period of weeks to months, depending on water temperature (Groot and Margolis, 1991; Novales Flamarique, 2005). Around the time of full yolk sac absorption, the fish rise from the stream gravel and adopt an active life style, as an alevin, feeding on various forms of zooplankton. As the alevin grows, it becomes a parr (fish >5·cm), which is a stage characterized by pronounced vertical bands along the body. This is followed by a physiological transformation termed smoltification that readies the fish (now termed a smolt) for life in sea water (Hoar, 1988). The smolt will enter the ocean and return to its home stream as an adult several years later to reproduce and begin the life cycle anew. Though all salmonids share a similar life cycle, different species will vary in their life history strategies (Groot and Margolis, 1991), with some (anadromous) species migrating to the ocean and others staying in fresh water (migrating to lakes). The rainbow trout is a landlocked salmonid belonging to the latter (non-anadromous) group.
W ater bodies worldwide are being invaded by non-native aquatic species. One of the primary vectors for these aquatic nuisance species invasions is ballast water. Aquatic nuisance species can be present in ballast water of vessels without cargo (and therefore with full ballast tanks), as well as in residual ballast of fully-loaded ships. Many species may seem too large to be transported by ballast water. Eggs, larvae and fully developed microscopic organisms, however, may be the ideal size to be sucked into a ballast tank and transported to the next port of call. Under the right conditions and without natural predators and parasites, non-native populations can increase dramatically, threatening or displacing native species and radically changing the natural ecosystem. Once estab- lished, aquatic nuisance species are difficult to manage and nearly impos- sible to eliminate.
ABSTRACT: Artificial lighting is being used more and more in the world. In developing countries, we can still find a widespread use of fuel based lighting but nowadays the situation is changing and the demand for electric based lighting is growing. Electric lighting consumes about 19% of the world total electricity use.Here a Pseudo Boost rectifier based electronicballast with a natural power factor correction (PFC) is proposed. Compared with existing single-phase bridgeless topologies, the proposed topology has the merits of less component counts. The absence of an input diode bridge and the presence of only one diode in the current path during each stage of the switching cycle result in higher power density and less conduction losses; hence, improved thermal management compared to existing PFC rectifiers is obtained. The proposed topology is designed to work in resonant mode to achieve an automatic PFC close to unity in a simple and effective manner.
WARNING: TO PREVENT HIGH VOLTAGE FROM BEING PRESENT ON RED AND YELLOW OUTPUT LEADS PRIOR TO INSTALLATION, INVERTER CONNECTOR MUST BE OPEN. DO NOT jOIN INVERTER CONNECTOR UNTIL INSTALLATION IS COMPLETE AND AC POWER IS SUPPLIED TO THE EMERGENCY BALLAST.
They are very economical when used in newly built urban road sections and remote rural areas without an electricity network. During daytime, the battery is charged by using PV panel and at night, the solar energy stored in the battery is released to power the streetlights. High- intensity-discharge (HID) lamps are commonly used as streetlight sources because of their high luminous efficacy, long lifetime and good color rendition. The HID lamp needs an auxiliary circuit called a “ballast” to ensure stable lamp operation because of its negative impedance characteristics. High conversion efficiency can be achieved due to only two-stage power conversion.
ABSTRACT: An LED driver with electronicballast that are currently commercially used is newly proposed, which adopts a variable switched capacitor by controlling the switching duty cycle for LED power regulation. The resonant frequency of an LC resonant tank of electronic ballasts can be changed, which makes the proposed LED driver versatile for electronic ballasts for various switching frequencies. In this way, the ﬂuorescent lamp is replaced with an LED lamp, where the electronicballast in the lighting infrastructure remains unchanged. The ZVS is applied for the variable switched capacitor (VSC) in the electronicballast. Neither an inductor nor a transformer is introduced in the proposed LED driver, which leads to compact size and high efficiency. Furthermore, no electrolytic capacitor is used, which is beneﬁcial for the long lifetime of LED drivers. This paper also presents a simple and efficient capacitor clamped current-sharing method for LED strings.
Heavy metal pollution in the port area had affected aquatic organisms. The research about the heavy metal content of ballast water of commercial vessels, both passen- ger or cargo vessels, berthing in Port of Tanjung Emas Semarang (PTES), has been conducted by using a method of AAS (Atomic Absorption Spectroscopy). Sample was gathered from vessels berthed in PTES, dated on December 18 th 2014 to October
MWNTs characterized by electron diffraction here were grown by d.c arc-discharge in hydrogen gas . Two important features that these nanotubes have are high-purity and a narrow channel in the center. The diameter of the innermost nanotubes is usually around 1.0 nm or less. Completely filled carbon nanotubes with the innermost core having the diameter roughly equal to the graphitic spacing was also observed before and in the present study. That was predicted to be (3, 3) armchair nanotube whose diameter was measured to be 0.4 nm from HRTEM images. From the example 6, we determined its chiral indices to be (5, 1) with a diameter of 0.436 nm in that case. The error in the diameter is due to low contrast seen in the central area of the nanotube in TEM images since smaller tubes have smaller number of carbon atoms. The nanotube (3, 3) is metallic whereas the nanotube (5, 1) is semiconducting. This shows the power of electron diffraction to determine the atomic structure of such small-scale molecules because one is going to be used as a nanowire while the other is as a nano-switch in future applications. That is why it is import to know the limitations in the current technique.
Hypothesis testing. The hypothesis that C. gattii VGII reached the Paciﬁc Northwest in ship ballast tanks from South America and then became subsequently established on land by a tidal wave suggests several lines of experimentation. Because South American ports are connected to other parts of the world by shipping lanes, other ports must also have become contaminated with C. gattii. The likelihood that C. gattii will become established in a particular locale is probably dependent on the physical and biological conditions operating in that locale. For example, amoebas are important biological control agents for C. neoformans in the environment (57, 58), and the type of micro- faunas found in different sites may determine the likelihood for the establishment of an invasive cryptococcal species. Although it is always possible that the marine ecology of the Paciﬁc Northwest provided a unique environment for C. gattii, the more likely scenario is that other coastal areas are also contaminated. Hence, a sampling of water in other ports by deep sequencing may reveal C. gattii-speciﬁc genes, thus strength- ening the case for shipborne transport. Similarly, sampling of waters in South American ports where rivers ﬂow from the interior of the continent may reveal C. gattii, support- ing the notion of ﬂuvial transport by land to sea transport. A more intensive search for new South American isolates may reveal a genetically close relative of the PNW strains, which would support recent transport from that region. Finding C. gattii in other coastal waters without a concomitant increase in cryptococcosis would support the notion that something different happened in the PNW and provide powerful indirect evidence for an unusual event, such as a tsunami. In fact, if C. gattii was found in coastal waters of areas that have suffered tsunamis in recent decades, such as following the Indonesian and Japanese earthquakes of 2004 and 2011, this could allow real-time studies in those areas and perhaps forestall future outbreaks of cryptococcosis in these locales. In this regard, it is noteworthy that the PNW tsunami event was separated from the C. gattii outbreak by 3 decades, suggesting that, if our hypothesis is correct, a period of land adaptation may be required before signiﬁcant numbers of human and animal cases appear. For example, land adaptation and selection by soil amoeboid predators may have been a necessary condition for increased virulence for mammal infection (59). Evidence for or against a tsunami-related movement from sea to land might come by careful bio-geographic analysis of land areas affected by the tidal wave for the
In this work, a highly effcient single-switch resonant boost converter with an energy-blocking diode was designed for use in a solar energy generation system. The structure of the proposed converter is simpler and cheaper than other resonant power converters, which require numerous components. The developed single-switch resonant power converter offers the advantages of soft switching, reduced switching losses, and increased energy conversion effciency. The perfomance of the proposed converter is analysed with the help of simulation results and the simulated effcency of the converter is found to be 94.4%. If the converter is connected to a PV energy generation system with Constant Voltage MPPT control, the system can be used as a battery charger without any feedback controllers as the output voltage of the converter remains constant.
Boost converters comprise complementary switch pairs, one of which is the control switch (controls the duty cycle) and the other capable of being implemented using a diode. Hybrid converter topologies can be synthesized by replacing the controlled switch with an inverter bridge network, either a single-phase or three-phase one. The proposed circuit modification principle, applied to a boost converter, is illustrated in the next section. The resulting converter, called BDHC, is the prime focus area of this paper. Section VI extends this principle to higher order converters .Each of the four bidirectional switches (Q1–Q4) of BDHC comprises the combination of a switch Si and an antiparallel diode Di (i = 1 to 4). The boost operation of the proposed converter can be realized by turning on both switches of any particular leg (either S1–S4 or S3–S2) simultaneously. This is equivalent to shootthrough switching condition as far as VSI operation is concerned, and it is strictly forbidden in the case of a conventional VSI [8-10]. However, for the proposed modification, this operation is equivalent to the switching “on” of the switch “Sa” of the conventional boost converter.
values of permittivity with respect to both the VMF and the TDSP techniques and proved to be not suitable to assess both the clean and the fouled ballast condition across all the investigated scenarios. A possible motivation for this mismatching falls within the amplitude-based nature of the own method and the coarse grain size and rough shape of the ballast aggregates. Indeed, the SRM relies on the value of the first-peak amplitude of the collected signal, which in turn depends on several factors including the configuration of the air-surface interface. In this regard, it is worth mentioning that the surface configuration of the four scenarios (i.e., the arrangement of the clean ballast aggregates at the top of the tank) has changed in all the investigated cases, due to the requirements of the testing protocol for laying out the material (i.e., Section 4.4.3). In addition, it is well-known how the wavelength of the signal is a critical survey parameter in the case of railway ballast, due to the variability of the dimension and shape of the aggregates, as well as of the volume of the air-filled voids (which can vary according to the fouling level). The consistency between the wavelength of a GPR signal and the dimension of the targets in a railway track bed (e.g., the ballast aggregates or the air voids) generates considerable scattering patterns and affects, amongst the other, the first-peak amplitude of the signal. As a rule of thumb, the lower is the frequency of investigation, the longer is the signal wavelength, the smaller will be the scattering generated by the ballast aggregates and the air voids. In such a case, the energy extracted to the signal will be lower [24, 46]. According to the wavelengths of the two central frequencies used in this study, it can be seen how the highest permittivity values closer to the above VMF (and TDSP) permittivity estimates (which are both expected to well approximate the searched dielectrics), were reached by the 1000 MHz GPR system (Fig. 10(b)). Indeed, this is due to the longer wavelength and the lower sensitivity of this antenna frequency towards the rough shape of the surface aggregates and the dimensions of the air voids. This fact generates less scattering and lower impact on the first-peak amplitude of the signal. Thereby, permittivity estimates much closer to the expected ones were reached.
Abstract: - Non conventional power and storage have made DC based domestic distribution an smart choice for future homes. This paper proposes Multi-Input-SingleSwitch (MISS) battery charger for DC nanogrids, instead of using different dedicated converters. The main aim of this work is to design a single stage boost converter with multiple inputs that can efficiently charge a battery for DC nano grids. The output of the converter is directly connected to a battery to save an additional converter stage for each source. Due to low power rating of the system, it is very important to minimize number of converter stages and use the generated energy efficiently. From various unidirectional renewable energy sources, different dedicated converters used, so this paper proposes a multiple input with a single stage boost converter that can efficiently destroy generated energy to charge a battery, Non conventional energy sources will have profitable value when some of the other sources are not great enough to command a dedicated converter. The converter is called Multi-Input-SingleSwitch (MISS) converter. The converter varies the duty cycle based on finest operation of the major power source (e.g., MPP in case of solar panel), where as the other smaller unidirectional sources act as slave. PV Module Maximum Power Point Tracker (MPPT) is a photovoltaic system that uses the photovoltaic array as a source of electrical power supply. Every photovoltaic (PV) array has an optimum operating point, called the maximum power point, which varies depending on cell temperature, the insulation level and array voltage. The function of MPPT is needed to operate the PV array at its maximum power point. Here Incremental conductance method can find the MPPT accurately; Incremental conductance method can track the MPPT at changing atmospheric conditions and efficiency also improved. The simulations are performed by using MATLAB/Simulink.