Science.gov

Sample records for harvesting

  1. Harvesting

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Since the introduction of the first successful mechanical harvester, mechanized cotton harvest has continued to decrease the cost and man hours required to produce a bale of cotton. Cotton harvesting in the US is completely mechanized and is accomplished by two primary machines, the spindle picker a...

  2. Noise Harvesting

    NASA Astrophysics Data System (ADS)

    Gammaitoni, L.; Cottone, F.; Neri, I.; Vocca, H.

    2009-04-01

    Kinetic energy harvesting has been the subject of a significant research effort in the last twenty years. Unfortunately most of the energy available at the microscales comes in the form of random vibrations with a wide spectrum of frequencies while standard harvesting methods are based on linear oscillators that are resonantly tuned in narrow frequency ranges. In this paper we present a novel approach based on the exploitation of nonlinear stochastic dynamics and show that, under proper conditions nonlinear oscillators can beat the standard linear approaches with significant increase in the harvesting efficency. For the sake of demonstration we present experimental results from a toy-model bistable oscillator made by a piezoelectric inverted pendulum.

  3. Cotton Harvesting

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cotton harvesting is performed in the US using either a spindle picker or brush-roll stripper. This presentation discusses the environmental, economic, geographic, and cultivar specific reasons behind a grower's choice to use either machine. The development of each machine system was discussed. A...

  4. Switchgrass harvest and storage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The feedstock characteristics of the conversion platform will influence the optimal harvest and post harvest management practices for switchgrass. However, many of the harvest management practices are tied to plant phenology and will be similar across platforms. Proper harvest and storage of switchg...

  5. Broadband pendulum energy harvester

    NASA Astrophysics Data System (ADS)

    Liang, Changwei; Wu, You; Zuo, Lei

    2016-09-01

    A novel electromagnetic pendulum energy harvester with mechanical motion rectifier (MMR) is proposed and investigated in this paper. MMR is a mechanism which rectifies the bidirectional swing motion of the pendulum into unidirectional rotation of the generator by using two one-way clutches in the gear system. In this paper, two prototypes of pendulum energy harvester with MMR and without MMR are designed and fabricated. The dynamic model of the proposed MMR pendulum energy harvester is established by considering the engagement and disengagement of the one way clutches. The simulation results show that the proposed MMR pendulum energy harvester has a larger output power at high frequencies comparing with non-MMR pendulum energy harvester which benefits from the disengagement of one-way clutch during pendulum vibration. Moreover, the proposed MMR pendulum energy harvester is broadband compare with non-MMR pendulum energy harvester, especially when the equivalent inertia is large. An experiment is also conducted to compare the energy harvesting performance of these two prototypes. A flywheel is attached at the end of the generator to make the disengagement more significant. The experiment results also verify that MMR pendulum energy harvester is broadband and has a larger output power at high frequency over the non-MMR pendulum energy harvester.

  6. Post-Harvest Physiology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Numerous plant microbial and physiological processes occur during forage harvest and storage and are almost always deleterious. These processes are influenced by preharvest factors such as mowing time of day, plant species, and maturity stage, as well as by harvest and storage variables. Avoidance o...

  7. Maple Sugar Harvesting/Wild Rice Harvesting.

    ERIC Educational Resources Information Center

    Minneapolis Public Schools, MN.

    Comprised of two separate booklets, this resource unit assists elementary teachers in explaining how the Ojibwe people harvest maple sugar and wild rice. The first booklet explains the procedure of tapping the maple trees for sap, preparation for boiling the sap, and the three forms the sugar is made into (granulated, "molded," and "taffy"). The…

  8. Harvesting rice's dispensable genome.

    PubMed

    Wing, Rod A

    2015-01-01

    A rapid and cost-effective approach has been developed to harvest and map the dispensable genome, that is, population-level natural sequence variation within a species that is not present in static genome assemblies. PMID:26429765

  9. Power Harvesting from Rotation?

    ERIC Educational Resources Information Center

    Chicone, Carmen; Feng, Z. C.

    2008-01-01

    We show the impossibility of harvesting power from rotational motions by devices attached to the rotating object. The presentation is suitable for students who have studied Lagrangian mechanics. (Contains 2 figures.)

  10. Water harvest via dewing.

    PubMed

    Lee, Anna; Moon, Myoung-Woon; Lim, Hyuneui; Kim, Wan-Doo; Kim, Ho-Young

    2012-07-10

    Harvesting water from humid air via dewing can provide a viable solution to a water shortage problem where liquid-phase water is not available. Here we experimentally quantify the effects of wettability and geometry of the condensation substrate on the water harvest efficiency. Uniformly hydrophilic surfaces are found to exhibit higher rates of water condensation and collection than surfaces with lower wettability. This is in contrast to a fog basking method where the most efficient surface consists of hydrophilic islands surrounded by hydrophobic background. A thin drainage path in the lower portion of the condensation substrate is revealed to greatly enhance the water collection efficiency. The optimal surface conditions found in this work can be used to design a practical device that harvests water as its biological counterpart, a green tree frog, Litoria caerulea , does during the dry season in tropical northern Australia. PMID:22731870

  11. Kenaf harvest decision matrix or how should I harvest kenaf?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The correct harvest method for kenaf (Hibiscus cannabinus L., Malvaceae) is dependent on many factors, including production location, equipment availability, storage options, processing plans, plant utilization, and economics. Since its first domestication, kenaf has consistently been hand-harveste...

  12. Pepper harvest technology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Peppers (Capsicum spp.) include a diverse collection of cultivars produced for a wide variety of end uses. This specialty crop and its processing industry are in the midst of a dual transition driven by labor cost and unavailability. Production and post-harvest processing is either converting to m...

  13. PEPPER HARVESTER DEVELOPMENT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Peppers (Capsicum spp.) include a diverse collection of cultivars produced for a wide variety of end uses. This specialty crop and its processing industry are in the midst of a transition driven by labor cost and unavailability. Production and post-harvest processing is either converting to mechan...

  14. Adaptive vibration energy harvesting

    NASA Astrophysics Data System (ADS)

    Behrens, Sam; Ward, John; Davidson, Josh

    2007-04-01

    By scavenging energy from their local environment, portable electronic devices such as mobile phones, radios and wireless sensors can achieve greater run-times with potentially lower weight. Vibration energy harvesting is one such approach where energy from parasitic vibrations can be converted into electrical energy, through the use of piezoelectric and electromagnetic transducers. Parasitic vibrations come from a range of sources such as wind, seismic forces and traffic. Existing approaches to vibration energy harvesting typically utilise a rectifier circuit, which is tuned to the resonant frequency of the harvesting structure and the dominant frequency of vibration. We have developed a novel approach to vibration energy harvesting, including adaption to non-periodic vibrations so as to extract the maximum amount of vibration energy available. Experimental results of an experimental apparatus using off-the-shelf transducer (i.e. speaker coil) show mechanical vibration to electrical energy conversion efficiencies of 27 - 34%. However, simulations of a more electro-mechanical efficient and lightly damped transducer show conversion efficiencies in excess of 80%.

  15. Advancements in Cotton Harvesting Research

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cotton harvesting research within USDA ARS is focused on improving harvest productivity, cotton quality, and producer profitability. In recent years, our work has encompassed efforts to improve both spindle picker and brush-roll stripper harvesting systems. Specifically, work with cotton pickers i...

  16. Green Chile Pepper Harvest Mechanization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pungent green chile (genus /Capsicum/, also spelled chili) is a large, fragile fruit growing on berry shrubs. Chile is harvested by hand to maximize yields and minimize fruit damage. Labor for hand harvesting chile is increasingly costly and difficult to obtain. Harvest mechanization is viewed as...

  17. Harvesting contaminants from liquid

    DOEpatents

    Simpson, John T.; Hunter, Scott R.

    2016-05-31

    Disclosed are examples of apparatuses for evaporative purification of a contaminated liquid. In each example, there is a vessel for storing the contaminated fluid. The vessel includes a surface coated with a layer of superhydrophobic material and the surface is at least partially in contact with the contaminated liquid. The contaminants do not adhere to the surface as the purified liquid evaporates, thus allowing the contaminants to be harvested.

  18. Piezoelectric Energy Harvesting Solutions

    PubMed Central

    Caliò, Renato; Rongala, Udaya Bhaskar; Camboni, Domenico; Milazzo, Mario; Stefanini, Cesare; de Petris, Gianluca; Oddo, Calogero Maria

    2014-01-01

    This paper reviews the state of the art in piezoelectric energy harvesting. It presents the basics of piezoelectricity and discusses materials choice. The work places emphasis on material operating modes and device configurations, from resonant to non-resonant devices and also to rotational solutions. The reviewed literature is compared based on power density and bandwidth. Lastly, the question of power conversion is addressed by reviewing various circuit solutions. PMID:24618725

  19. Light-harvesting dendrimers.

    PubMed

    Balzani, Vincenzo; Ceroni, Paola; Maestri, Mauro; Vicinelli, Veronica

    2003-12-01

    Dendrimers are well-defined, tree-like macromolecules, with a high degree of order and the possibility to contain selected chemical units in predetermined sites of their structure. Dendrimers are currently attracting the interest of many scientists because of their unusual chemical and physical properties and the wide range of potential applications. It is possible to design and synthesize dendrimers containing a variety of chromophoric groups organized in the dimensions of time, energy and space so as to obtain efficient light-harvesting devices that can be useful for solar energy conversion and other purposes. PMID:14644173

  20. Water harvesting applications for rangelands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although water harvesting techniques have been used effectively in irrigated agriculture and domestic water supplies, there seems to have been little continued exploitation of the same techniques in arid and semiarid rangeland restoration. A review of the history of rangeland water harvesting allow...

  1. The Spindle Type Cotton Harvester

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The spindle type cotton picker was commercialized during the mid 1900’s and is currently produced by two US agricultural equipment manufacturers, John Deere and CaseIH. Picking is the predominate machine harvest method used throughout the US and world. Harvesting efficiency of a spindle type cotton ...

  2. Electrochemically driven mechanical energy harvesting

    NASA Astrophysics Data System (ADS)

    Kim, Sangtae; Choi, Soon Ju; Zhao, Kejie; Yang, Hui; Gobbi, Giorgia; Zhang, Sulin; Li, Ju

    2016-01-01

    Efficient mechanical energy harvesters enable various wearable devices and auxiliary energy supply. Here we report a novel class of mechanical energy harvesters via stress-voltage coupling in electrochemically alloyed electrodes. The device consists of two identical Li-alloyed Si as electrodes, separated by electrolyte-soaked polymer membranes. Bending-induced asymmetric stresses generate chemical potential difference, driving lithium ion flux from the compressed to the tensed electrode to generate electrical current. Removing the bending reverses ion flux and electrical current. Our thermodynamic analysis reveals that the ideal energy-harvesting efficiency of this device is dictated by the Poisson's ratio of the electrodes. For the thin-film-based energy harvester used in this study, the device has achieved a generating capacity of 15%. The device demonstrates a practical use of stress-composition-voltage coupling in electrochemically active alloys to harvest low-grade mechanical energies from various low-frequency motions, such as everyday human activities.

  3. Electrochemically driven mechanical energy harvesting

    PubMed Central

    Kim, Sangtae; Choi, Soon Ju; Zhao, Kejie; Yang, Hui; Gobbi, Giorgia; Zhang, Sulin; Li, Ju

    2016-01-01

    Efficient mechanical energy harvesters enable various wearable devices and auxiliary energy supply. Here we report a novel class of mechanical energy harvesters via stress–voltage coupling in electrochemically alloyed electrodes. The device consists of two identical Li-alloyed Si as electrodes, separated by electrolyte-soaked polymer membranes. Bending-induced asymmetric stresses generate chemical potential difference, driving lithium ion flux from the compressed to the tensed electrode to generate electrical current. Removing the bending reverses ion flux and electrical current. Our thermodynamic analysis reveals that the ideal energy-harvesting efficiency of this device is dictated by the Poisson's ratio of the electrodes. For the thin-film-based energy harvester used in this study, the device has achieved a generating capacity of 15%. The device demonstrates a practical use of stress-composition–voltage coupling in electrochemically active alloys to harvest low-grade mechanical energies from various low-frequency motions, such as everyday human activities. PMID:26733282

  4. A Hip Implant Energy Harvester

    NASA Astrophysics Data System (ADS)

    Pancharoen, K.; Zhu, D.; Beeby, S. P.

    2014-11-01

    This paper presents a kinetic energy harvester designed to be embedded in a hip implant which aims to operate at a low frequency associated with body motion of patients. The prototype is designed based on the constrained volume available in a hip prosthesis and the challenge is to harvest energy from low frequency movements (< 1 Hz) which is an average frequency during free walking of a patient. The concept of magnetic-force-driven energy harvesting is applied to this prototype considering the hip movements during routine activities of patients. The magnetic field within the harvester was simulated using COMSOL. The simulated resonant frequency was around 30 Hz and the voltage induced in a coil was predicted to be 47.8 mV. A prototype of the energy harvester was fabricated and tested. A maximum open circuit voltage of 39.43 mV was obtained and the resonant frequency of 28 Hz was observed. Moreover, the power output of 0.96 μW was achieved with an optimum resistive load of 250Ω.

  5. A multiaxial piezoelectric energy harvester

    NASA Astrophysics Data System (ADS)

    Mousselmal, H. D.; Cottinet, P. J.; Quiquerez, L.; Remaki, B.; Petit, L.

    2013-04-01

    An important limitation in the classical energy harvesters based on cantilever beam structure is its monodirectional sensibility. The external excitation must generate an orthogonal acceleration from the beam plane to induced flexural deformation. If the direction of the excitation deviates from this privileged direction, the harvester output power is drastically reduced. This point is obviously very restrictive in the case of an arbitrary excitation direction induced for example by human body movements or vehicles vibrations. In order to overcome this issue of the conventional resonant cantilever configuration with seismic mass, a multidirectional harvester is introduced here by the authors. The multidirectional ability relies on the exploitation of 3 degenerate structural vibration modes where each of them is induced by the corresponding component of the acceleration vector. This specific structure has been already used for 3 axis accelerometers but the approach is here totally revisited because the final functional goal is different. This paper presents the principle and the design considerations of such multidirectional piezoelectric energy harvester. A finite element model has been used for the harvester optimisation. It has been shown that the seismic mass is a relevant parameter for the modes tuning because the resonant frequency of the 1st exploited flexural mode directly depends on the mass whereas the resonance frequency of the 2nd flexural mode depends on its moment of inertia. A simplified centimetric prototype limited to a two orthogonal direction sensibility has permitted to valid the theoretical approach.

  6. Vibro-impacting power harvester

    NASA Astrophysics Data System (ADS)

    Moss, Scott; Powlesland, Ian; Galea, Stephen; Carman, Gregory

    2010-04-01

    The certification of retro-fitted structural health monitoring (SHM) systems for use on aircraft raises a number of challenges. One critical issue is determining the optimal means of supplying power to these systems, given that access to the existing aircraft power-system is often problematic. Previously, the DSTO has shown that a structural-strain based energy harvesting approach can be used to power a device for SHM of aircraft structure. Acceleration-based power harvesting from airframes can be more demanding than a strain based approach because the vibration spectrum of an aircraft structure can vary dynamically with flight conditions. A vibration spectrum with varying frequency may severely limit the power harvested by a single-degree-of-freedom resonance-based device, and hence a frequency agile or (relatively) broadband device is often required to maximize the energy harvested. This paper reports on an investigation into the use of a vibro-impact approach to construct an acceleration-based power harvester that can operate in the frequency range 29-41 Hz.

  7. Piezoelectric Water Drop Energy Harvesting

    NASA Astrophysics Data System (ADS)

    Al Ahmad, Mahmoud

    2014-02-01

    Piezoelectric materials convert mechanical deformation directly into electrical charges, which can be harvested and used to drive micropower electronic devices. The low power consumption of such systems on the scale of microwatts leads to the possibility of using harvested vibrational energy due to its almost universal nature. Vibrational energy harvested using piezoelectric cantilevers provides sufficient output for small-scale power applications. This work reports on vibrational energy harvesting from free-falling droplets at the tip of lead zirconate titanate piezoelectric-based cantilevers. The harvester incorporates a multimorph clamped-free cantilever made of lead zirconate titanate piezoelectric thick films. During the impact, the droplet's kinetic energy is transferred to the form of mechanical stress, forcing the piezoelectric structure to vibrate and thereby producing charges. Experimental results show an instantaneous drop-power of 2.15 mW cm-3 g-1. The scenario of a medium intensity of falling water drops, i.e., 200 drops per second, yielded a power of 0.48 W cm-3 g-1 per second.

  8. Minimally invasive posterior hamstring harvest.

    PubMed

    Wilson, Trent J; Lubowitz, James H

    2013-01-01

    Autogenous hamstring harvesting for knee ligament reconstruction is a well-established standard. Minimally invasive posterior hamstring harvest is a simple, efficient, reproducible technique for harvest of the semitendinosus or gracilis tendon or both medial hamstring tendons. A 2- to 3-cm longitudinal incision from the popliteal crease proximally, in line with the semitendinosus tendon, is sufficient. The deep fascia is bluntly penetrated, and the tendon or tendons are identified. Adhesions are dissected. Then, an open tendon stripper is used to release the tendon or tendons proximally; a closed, sharp tendon stripper is used to release the tendon or tendons from the pes. Layered, absorbable skin closure is performed, and the skin is covered with a skin sealant, bolster dressing, and plastic adhesive bandage for 2 weeks. PMID:24266003

  9. Piezoelectric MEMS for energy harvesting

    NASA Astrophysics Data System (ADS)

    Kanno, Isaku

    2015-12-01

    Recently, piezoelectric MEMS have been intensively investigated to create new functional microdevices, and some of them have already been commercialized such as MEMS gyrosensors or miropumps of inkjet printer head. Piezoelectric energy harvesting is considered to be one of the promising future applications of piezoelectric MEMS. In this report, we introduce the deposition of the piezoelectric PZT thin films as well as lead-free KNN thin films. We fabricated piezoelectric energy harvesters of PZT and KNN thin films deposited on stainless steel cantilevers and compared their power generation performance.

  10. Harvesting of algae by froth flotation.

    PubMed

    LEVIN, G V; CLENDENNING, J R; GIBOR, A; BOGAR, F D

    1962-03-01

    A highly efficient froth flotation procedure has been developed for harvesting algae from dilute suspensions. The method does not depend upon the addition of flotants. Harvesting is carried out in a long column containing the feed solution which is aerated from below. A stable column of foam is produced and harvested from a side arm near the top of the column. The cell concentration of the harvest is a function of pH, aeration rate, aerator porosity, feed concentration, and height of foam in the harvesting column. The economic aspects of this process seem favorable for mass harvesting of algae for food or other purposes. PMID:14464557

  11. Sustainable Corn Stover Harvest Strategies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn stover has been identified as an important initial source of biomass for conversion to ethanol and other biofuels. This poster presentation outlines on-going cooperative research being conducted near Ames, IA. Our university partner is responsible for developing the one-pass harvester and our I...

  12. Harvesting the Ocean: Teachers' Handbook.

    ERIC Educational Resources Information Center

    Caton, Albert, Ed.; And Others

    This teaching guide is designed for use with three units of study (presented in separate booklets titled "The Ocean,""The Harvest," and "Using the Sea Wisely"). The multidisciplinary units contain teaching and learning resources designed to provide: students with learning experiences using a variety of thinking processes; learning experiences in…

  13. Noise powered nonlinear energy harvesting

    NASA Astrophysics Data System (ADS)

    Gammaitoni, Luca; Neri, Igor; Vocca, Helios

    2011-04-01

    The powering of small-scale electronic mobile devices has been in recent years the subject of a great number of research efforts aimed primarily at finding an alternative solution to standard batteries. The harvesting of kinetic energy present in the form of random vibrations (from non-equilibrium thermal noise up to machine vibrations) is an interesting option due to the almost universal presence of some kind of motion. Present working solutions for vibration energy harvesting are based on oscillating mechanical elements that convert kinetic energy via capacitive, inductive or piezoelectric methods. These oscillators are usually designed to be resonantly tuned to the ambient dominant frequency. However, in most cases the ambient random vibrations have their energy distributed over a wide spectrum of frequencies, especially at low frequency, and frequency tuning is not always possible due to geometrical/dynamical constraints. We present a new approach to the powering of small autonomous sensors based on vibration energy harvesting by the exploitation of nonlinear stochastic dynamics. Such a method is shown to outperform standard linear approaches based on the use of resonant oscillators and to overcome some of the most severe limitations of present strategies, like narrow bandwidth, need for continuous frequency tuning and low power efficiency. We demonstrate the superior performances of this method by applying it to piezoelectric energy harvesting from ambient vibration.

  14. Fluid flow nozzle energy harvesters

    NASA Astrophysics Data System (ADS)

    Sherrit, Stewart; Lee, Hyeong Jae; Walkemeyer, Phillip; Winn, Tyler; Tosi, Luis Phillipe; Colonius, Tim

    2015-04-01

    Power generation schemes that could be used downhole in an oil well to produce about 1 Watt average power with long-life (decades) are actively being developed. A variety of proposed energy harvesting schemes could be used to extract energy from this environment but each of these has their own limitations that limit their practical use. Since vibrating piezoelectric structures are solid state and can be driven below their fatigue limit, harvesters based on these structures are capable of operating for very long lifetimes (decades); thereby, possibly overcoming a principle limitation of existing technology based on rotating turbo-machinery. An initial survey [1] identified that spline nozzle configurations can be used to excite a vibrating piezoelectric structure in such a way as to convert the abundant flow energy into useful amounts of electrical power. This paper presents current flow energy harvesting designs and experimental results of specific spline nozzle/ bimorph design configurations which have generated suitable power per nozzle at or above well production analogous flow rates. Theoretical models for non-dimensional analysis and constitutive electromechanical model are also presented in this paper to optimize the flow harvesting system.

  15. Harvest prediction in `Algerie' loquat

    NASA Astrophysics Data System (ADS)

    Hueso, Juan J.; Pérez, Mercedes; Alonso, Francisca; Cuevas, Julián

    2007-05-01

    Plant phenology is in great measure driven by air temperature. To forecast harvest time for ‘Algerie’ loquat accurately, the growing degree days (GDD) needed from bloom to ripening were determined using data from nine seasons. The methods proposed by Zalom et al. (Zalom FG, Goodell PB, Wilson LT, Barnett WW, Bentley W, Degree-days: the calculation and use of heat units in pest management, leaflet no 21373, Division Agriculture and Natural Resources, University of California 10 pp, 1983) were compared as regards their ability to estimate heat summation based on hourly records. All the methods gave remarkably similar results for our cultivation area, although the double-sine method showed higher performance when temperatures were low. A base temperature of 3°C is proposed for ‘Algerie’ loquat because it provides a coefficient of variation in GDD among seasons of below 5%, and because of its compatibility with loquat growth. Based on these determinations, ‘Algerie’ loquat requires 1,715 GDD from bloom to harvest; under our conditions this heat is accumulated over an average of 159 days. Our procedure permits the ‘Algerie’ harvest date to be estimated with a mean error of 4.4 days (<3% for the bloom-harvest period). GDD summation did not prove superior to the use of the number of calendar days for predicting ‘Algerie’ harvest under non-limiting growing conditions. However, GDD reflects the developmental rate in water-stressed trees better than calendar days. Trees under deficit irrigation during flower development required more time and more heat to ripen their fruits.

  16. Nyala and Bushbuck II: A Harvesting Model.

    ERIC Educational Resources Information Center

    Fay, Temple H.; Greeff, Johanna C.

    1999-01-01

    Adds a cropping or harvesting term to the animal overpopulation model developed in Part I of this article. Investigates various harvesting strategies that might suggest a solution to the overpopulation problem without actually culling any animals. (ASK)

  17. Proso Millet Harvest: A Comparison of Conventional Harvest and Direct Harvest with a Stripper Header

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This research was conducted to determine if proso millet can be harvested with a stripper header. Stripper headers use extremely fast rotating metal teeth to rip the seed off the plant and leave the majority of residue standing in the field as opposed to cutting off the entire plant and running tha...

  18. Energy harvesting devices for harvesting energy from terahertz electromagnetic radiation

    DOEpatents

    Novack, Steven D.; Kotter, Dale K.; Pinhero, Patrick J.

    2012-10-09

    Methods, devices and systems for harvesting energy from electromagnetic radiation are provided including harvesting energy from electromagnetic radiation. In one embodiment, a device includes a substrate and one or more resonance elements disposed in or on the substrate. The resonance elements are configured to have a resonant frequency, for example, in at least one of the infrared, near-infrared and visible light spectra. A layer of conductive material may be disposed over a portion of the substrate to form a ground plane. An optical resonance gap or stand-off layer may be formed between the resonance elements and the ground plane. The optical resonance gap extends a distance between the resonance elements and the layer of conductive material approximately one-quarter wavelength of a wavelength of the at least one resonance element's resonant frequency. At least one energy transfer element may be associated with the at least one resonance element.

  19. Fundamental Limits to Nonlinear Energy Harvesting

    NASA Astrophysics Data System (ADS)

    Haji Hosseinloo, Ashkan; Turitsyn, Konstantin

    2015-12-01

    Linear and nonlinear vibration energy harvesting has been the focus of considerable research in recent years. However, fundamental limits on the harvestable energy of a harvester subjected to an arbitrary excitation force and different constraints is not yet fully understood. Understanding these limits is not only essential for an assessment of the technology potential, but it also provides a broader perspective on the current harvesting mechanisms and guidance in their improvement. Here, we derive the fundamental limits on the output power of an ideal energy harvester for arbitrary excitation waveforms and build on the current analysis framework for the simple computation of this limit for more sophisticated setups. We show that the optimal harvester maximizes the harvested energy through a mechanical analog of a buy-low-sell-high strategy. We also propose a nonresonant passive latch-assisted harvester to realize this strategy for an effective harvesting. It is shown that the proposed harvester harvests energy more effectively than its linear and bistable counterparts over a wider range of excitation frequencies and amplitudes. The buy-low-sell-high strategy also reveals why the conventional bistable harvester works well at low-frequency excitation.

  20. Water Harvesting II: Working toward Being Green

    ERIC Educational Resources Information Center

    Farenga, Stephen J.; Ness, Daniel; Craven, John A.

    2008-01-01

    As you have read in the previous "After the Bell" column, water harvesting is a process of diverting and collecting rainwater. One of the main reasons to harvest rainwater is to reduce the demand on local sources of water. The objective of the harvesting procedure is to gather water from a weather event that is usually lost as runoff and either…

  1. 25 CFR 163.12 - Harvesting restrictions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Harvesting restrictions. 163.12 Section 163.12 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations § 163.12 Harvesting restrictions. (a) Harvesting timber on commercial forest...

  2. 25 CFR 163.12 - Harvesting restrictions.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false Harvesting restrictions. 163.12 Section 163.12 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations § 163.12 Harvesting restrictions. (a) Harvesting timber on commercial forest...

  3. 25 CFR 163.12 - Harvesting restrictions.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Harvesting restrictions. 163.12 Section 163.12 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations § 163.12 Harvesting restrictions. (a) Harvesting timber on commercial forest...

  4. 25 CFR 163.12 - Harvesting restrictions.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Harvesting restrictions. 163.12 Section 163.12 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations § 163.12 Harvesting restrictions. (a) Harvesting timber on commercial forest...

  5. 25 CFR 163.12 - Harvesting restrictions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Harvesting restrictions. 163.12 Section 163.12 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations § 163.12 Harvesting restrictions. (a) Harvesting timber on commercial forest...

  6. Approaches to automated protein crystal harvesting

    SciTech Connect

    Deller, Marc C. Rupp, Bernhard

    2014-01-28

    Approaches to automated and robot-assisted harvesting of protein crystals are critically reviewed. While no true turn-key solutions for automation of protein crystal harvesting are currently available, systems incorporating advanced robotics and micro-electromechanical systems represent exciting developments with the potential to revolutionize the way in which protein crystals are harvested.

  7. Nonlinear piezomagnetoelastic harvester array for broadband energy harvesting

    NASA Astrophysics Data System (ADS)

    Upadrashta, Deepesh; Yang, Yaowen

    2016-08-01

    This article proposes an array of nonlinear piezomagnetoelastic energy harvesters (NPEHs) for scavenging electrical energy from broadband vibrations with low amplitudes (<2 m/s2). The array consists of monostable NPEHs combined to generate useful power output (˜100 μW) over wide bandwidth. The nonlinearity in each of the NPEHs is induced by the magnetic interaction between an embedded magnet in the tip mass of cantilever and a fixed magnet clamped to the rigid platform. The dynamic responses of two NPEHs, one with attractive configuration and the other with repulsive configuration, are combined to achieve a bandwidth of 3.3 Hz at a power level of 100 μW. A parametric study is carried out to obtain the gap distances between the magnets to achieve wide bandwidth. Experiments are performed to validate the proposed idea, the theoretical predictions, and to demonstrate the advantage of array of NPEHs over the array of linear piezoelectric energy harvesters (LPEHs). The experiments have clearly shown the advantage of NPEH array over its linear counterpart under both harmonic and random excitations. Approximately, 100% increase in the operation bandwidth is achieved by the NPEH array at harmonic excitation level of 2 m/s2. The NPEH array exhibits up to 80% improvement in the accumulated energy under random excitation when compared with the LPEH array. Furthermore, the performance of NPEH array with series and parallel connections between the individual harvesters using standard AC/DC interface circuits is also investigated and compared with its linear counterpart.

  8. Fruit harvesting robots in Japan.

    PubMed

    Kondo, N; Monta, M; Fujiura, T

    1996-01-01

    We have developed harvesting robots for tomato, petty-tomato, cucumber and grape in Japan. These robots mainly consist of manipulators, end-effectors, visual sensors and traveling devices. These mechanisms of the robot components were developed based on the physical properties of the work objects. The robots must work automatically by themselves in greenhouses or fields, since we are considering for one operator to tend several robots in the production system. The system is modeled after Japanese agriculture which is commonly seen to produce many kinds of crops in greenhouses and in many small fields intensively. Bioproduction in space is somewhat similar to the agricultural system in Japan, because few operators have to work in a small space. Employing robots for bioproduction in space is considered desirable in near future. The following is a description of the harvesting robots. PMID:11538961

  9. Principles of thermoacoustic energy harvesting

    NASA Astrophysics Data System (ADS)

    Avent, A. W.; Bowen, C. R.

    2015-11-01

    Thermoacoustics exploit a temperature gradient to produce powerful acoustic pressure waves. The technology has a key role to play in energy harvesting systems. A time-line in the development of thermoacoustics is presented from its earliest recorded example in glass blowing through to the development of the Sondhauss and Rijke tubes to Stirling engines and pulse-tube cryo-cooling. The review sets the current literature in context, identifies key publications and promising areas of research. The fundamental principles of thermoacoustic phenomena are explained; design challenges and factors influencing efficiency are explored. Thermoacoustic processes involve complex multi-physical coupling and transient, highly non-linear relationships which are computationally expensive to model; appropriate numerical modelling techniques and options for analyses are presented. Potential methods of harvesting the energy in the acoustic waves are also examined.

  10. Forage Harvest and Transport Costs

    SciTech Connect

    Butler, J.; Downing, M.; Turhollow, A.

    1998-12-01

    An engineering-economic approach is used to calculate harvest, in-field transport, and over-the-road transport costs for hay as bales and modules, silage, and crop residues as bales and modules. Costs included are equipment depreciation interest; fuel, lube, and oil; repairs; insurance, housing, and taxes; and labor. Field preparation, pest control, fertilizer, land, and overhead are excluded from the costs calculated Equipment is constrained by power available, throughput or carrying capacity, and field speed.

  11. Motorcycle waste heat energy harvesting

    NASA Astrophysics Data System (ADS)

    Schlichting, Alexander D.; Anton, Steven R.; Inman, Daniel J.

    2008-03-01

    Environmental concerns coupled with the depletion of fuel sources has led to research on ethanol, fuel cells, and even generating electricity from vibrations. Much of the research in these areas is stalling due to expensive or environmentally contaminating processes, however recent breakthroughs in materials and production has created a surge in research on waste heat energy harvesting devices. The thermoelectric generators (TEGs) used in waste heat energy harvesting are governed by the Thermoelectric, or Seebeck, effect, generating electricity from a temperature gradient. Some research to date has featured platforms such as heavy duty diesel trucks, model airplanes, and automobiles, attempting to either eliminate heavy batteries or the alternator. A motorcycle is another platform that possesses some very promising characteristics for waste heat energy harvesting, mainly because the exhaust pipes are exposed to significant amounts of air flow. A 1995 Kawasaki Ninja 250R was used for these trials. The module used in these experiments, the Melcor HT3-12-30, produced an average of 0.4694 W from an average temperature gradient of 48.73 °C. The mathematical model created from the Thermoelectric effect equation and the mean Seebeck coefficient displayed by the module produced an average error from the experimental data of 1.75%. Although the module proved insufficient to practically eliminate the alternator on a standard motorcycle, the temperature data gathered as well as the examination of a simple, yet accurate, model represent significant steps in the process of creating a TEG capable of doing so.

  12. Scaling effects for piezoelectric energy harvesters

    NASA Astrophysics Data System (ADS)

    Zhu, D.; Beeby, S. P.

    2015-05-01

    This paper presents a fundamental investigation into scaling effects for the mechanical properties and electrical output power of piezoelectric vibration energy harvesters. The mechanical properties investigated in this paper include resonant frequency of the harvester and its frequency tunability, which is essential for the harvester to operate efficiently under broadband excitations. Electrical output power studied includes cases when the harvester is excited under both constant vibration acceleration and constant vibration amplitude. The energy harvester analysed in this paper is based on a cantilever structure, which is typical of most vibration energy harvesters. Both detailed mathematical derivation and simulation are presented. Furthermore, various piezoelectric materials used in MEMS and non-MEMS harvesters are also considered in the scaling analysis.

  13. Harvesting dental stem cells - Overview

    PubMed Central

    Sunil, P. M.; Manikandan, Ramanathan; Muthumurugan; Yoithapprabhunath, Thukanayakanpalayam Ragunathan; Sivakumar, Muniapillai

    2015-01-01

    Dental stem cells have recently become one of the widely researched areas in dentistry. Ever since the identification of stem cells from various dental tissues like deciduous teeth, dental papilla, periodontal ligament and third molars, storing them for future use for various clinical applications was being explored. Dental stem cells were harvested and isolated using various techniques by different investigators and laboratories. This article explains the technical aspects of preparing the patient, atraumatic and aseptic removal of the tooth and its safe transportation and preservation for future expansion. PMID:26538883

  14. Harvesting dental stem cells - Overview.

    PubMed

    Sunil, P M; Manikandan, Ramanathan; Muthumurugan; Yoithapprabhunath, Thukanayakanpalayam Ragunathan; Sivakumar, Muniapillai

    2015-08-01

    Dental stem cells have recently become one of the widely researched areas in dentistry. Ever since the identification of stem cells from various dental tissues like deciduous teeth, dental papilla, periodontal ligament and third molars, storing them for future use for various clinical applications was being explored. Dental stem cells were harvested and isolated using various techniques by different investigators and laboratories. This article explains the technical aspects of preparing the patient, atraumatic and aseptic removal of the tooth and its safe transportation and preservation for future expansion. PMID:26538883

  15. Tunable nonlinear piezoelectric vibration harvester

    NASA Astrophysics Data System (ADS)

    Neiss, S.; Goldschmidtboeing, F.; Kroener, M.; Woias, P.

    2014-11-01

    Nonlinear piezoelectric energy harvesting generators can provide a large bandwidth combined with a good resonant power output. However, the frequency response is characterized by a strong hysteresis making a technical use difficult if the hysteresis cannot be compensated. We propose a tuning mechanism that allows both, a compensation of the hysteresis as well as maintaining the optimal work point. The compensation algorithm can reduce the hysteresis to a minimum of only 1.5 Hz and maintain a high energy oscillation in a large frequency window between 53.3 Hz and 74.5 Hz.

  16. Porous ferroelectrics for energy harvesting applications

    NASA Astrophysics Data System (ADS)

    Roscow, J.; Zhang, Y.; Taylor, J.; Bowen, C. R.

    2015-11-01

    This paper provides an overview of energy harvesting using ferroelectric materials, with a particular focus on the energy harvesting capabilities of porous ferroelectric ceramics for both piezo- and pyroelectric harvesting. The benefits of introducing porosity into ferro- electrics such as lead zirconate titanate (PZT) has been known for over 30 years, but the potential advantages for energy harvesting from both ambient vibrations and temperature fluctuations have not been studied in depth. The article briefly discusses piezoelectric and pyro- electric energy harvesting, before evaluating the potential benefits of porous materials for increasing energy harvesting figures of merits and electromechanical/electrothermal coupling factors. Established processing routes are evaluated in terms of the final porous structure and the resulting effects on the electrical, thermal and mechanical properties.

  17. Controlling Light Harvesting with Light.

    PubMed

    Gwizdala, Michal; Berera, Rudi; Kirilovsky, Diana; van Grondelle, Rienk; Krüger, Tjaart P J

    2016-09-14

    When exposed to intense sunlight, all organisms performing oxygenic photosynthesis implement various photoprotective strategies to prevent potentially lethal photodamage. The rapidly responding photoprotective mechanisms, occurring in the light-harvesting pigment-protein antennae, take effect within tens of seconds, while the dramatic and potentially harmful light intensity fluctuations manifest also on shorter time scales. Here we show that, upon illumination, individual phycobilisomes from Synechocystis PCC 6803, which, in vivo under low-light conditions, harvest solar energy, and have the built-in capacity to switch rapidly and reversibly into light-activated energy-dissipating states. Simultaneously measured fluorescence intensity, lifetime, and spectra, compared with a multicompartmental kinetic model, revealed that essentially any subunit of a phycobilisome can be quenched, and that the core complexes were targeted most frequently. Our results provide the first evidence for fluorescence blinking from a biologically active system at physiological light intensities and suggest that the light-controlled switches to intrinsically available energy-dissipating states are responsible for a novel type of photoprotection in cyanobacteria. We anticipate other photosynthetic organisms to employ similar strategies to respond instantly to rapid solar light intensity fluctuations. A detailed understanding of the photophysics of photosynthetic antenna complexes is of great interest for bioinspired solar energy technologies. PMID:27546794

  18. Rooftop level rainwater harvesting system

    NASA Astrophysics Data System (ADS)

    Traboulsi, Hayssam; Traboulsi, Marwa

    2015-05-01

    Unfortunately, in Lebanon and other countries in the Middle East region, water becomes scarcer than ever before, and over the last decades the demand on domestic water has increased due to population and economic growth. Although rainwater harvesting is considered to be a safe and reliable alternative source for domestic water, the inconvenience or impracticalities related to the cost and space needed for the construction of ground or underground storage tanks makes this practice not widely common in rural areas and rarely implemented in urban cities. This paper introduces a new technique to rainwater harvesting which can be easily used in both rural and urban areas: it collects and stores rainwater directly in tanks already installed on building roofs and not necessarily in special ground or underground ones. If widely adopted in Lebanon, this technique could help in: (1) collecting around 23 MCM (70 % of the current deficit in the domestic water supply) of rainwater and thus increasing the available water per m2 of building by 0.4 m3 per year, (2) saving around 7 % of the amount of electric energy usually needed to pump water from an aquifer well and ground or underground tank, and (3) considerably reducing the rate of surface runoff of rainwater at the coastal zones where rainwater is not captured at all and goes directly to the sea.

  19. Vibration energy harvester optimization using artificial intelligence

    NASA Astrophysics Data System (ADS)

    Hadas, Z.; Ondrusek, C.; Kurfurst, J.; Singule, V.

    2011-06-01

    This paper deals with an optimization study of a vibration energy harvester. This harvester can be used as autonomous source of electrical energy for remote or wireless applications, which are placed in environment excited by ambient mechanical vibrations. The ambient energy of vibrations is usually on very low level but the harvester can be used as alternative source of energy for electronic devices with an expected low level of power consumption of several mW. The optimized design of the vibration energy harvester was based on previous development and the sensitivity of harvester design was improved for effective harvesting from mechanical vibrations in aeronautic applications. The vibration energy harvester is a mechatronic system which generates electrical energy from ambient vibrations due to precision tuning up generator parameters. The optimization study for maximization of harvested power or minimization of volume and weight are the main goals of our development. The optimization study of such complex device is complicated therefore artificial intelligence methods can be used for tuning up optimal harvester parameters.

  20. Apparatus and method for harvesting woody plantations

    DOEpatents

    Eggen, David L.

    1988-11-15

    A tree harvester for harvesting felled trees includes a wheel mounted wood chipper which moves toward the butt ends of the tree stems to be processed. The harvester includes a plurality of rotating alignment discs in front of the chipper. These discs align the tree stems to be processed with the mouth of the chipper. A chipper infeed cylinder is rotatably mounted between the discs and the front end of the chipper, and lifts the tree stem butts up from the ground into alignment with the chipper inlet port. The chips discharge from the chipper and go into a chip hopper which moves with the tree harvester.

  1. Apparatus and method for harvesting woody plantations

    DOEpatents

    Eggen, D.L.

    1988-11-15

    A tree harvester for harvesting felled trees includes a wheel mounted wood chipper which moves toward the butt ends of the tree stems to be processed. The harvester includes a plurality of rotating alignment discs in front of the chipper. These discs align the tree stems to be processed with the mouth of the chipper. A chipper infeed cylinder is rotatably mounted between the discs and the front end of the chipper, and lifts the tree stem butts up from the ground into alignment with the chipper inlet port. The chips discharge from the chipper and go into a chip hopper which moves with the tree harvester. 8 figs.

  2. Synchronized charge extraction for aeroelastic energy harvesting

    NASA Astrophysics Data System (ADS)

    Zhao, Liya; Tang, Lihua; Wu, Hao; Yang, Yaowen

    2014-03-01

    Aeroelastic instabilities have been frequently exploited for energy harvesting purpose to power standalone electronic systems, such as wireless sensors. Meanwhile, various energy harvesting interface circuits, such as synchronized charge extraction (SCE) and synchronized switching harvesting on inductor (SSHI), have been widely pursued in the literature for efficiency enhancement of energy harvesting from existing base vibrations. These interfaces, however, have not been applied for aeroelastic energy harvesting. This paper investigates the feasibility of the SCE interface in galloping-based piezoelectric energy harvesting, with a focus on its benefit for performance improvement and influence on the galloping dynamics in different electromechanical coupling regimes. A galloping-based piezoelectric energy harvester (GPEH) is prototyped with an aluminum cantilever bonded with a piezoelectric sheet. Wind tunnel test is conducted with a simple electrical interface composed of a resistive load. Circuit simulation is performed with equivalent circuit representation of the GPEH system and confirmed by experimental results. Consequently, a self-powered SCE interface is implemented with the capability of self peak-detecting and switching. Circuit simulation for various electromechanical coupling cases shows that the harvested power with SCE interface for GPEH is independent of the electrical load, similar to that for a vibration-based piezoelectric energy harvester (VPEH). The SCE interface outperforms the standard interface if the electromechanical coupling is weak, and requires much less piezoelectric material to achieve the maximum power output. Moreover, influence of electromechanical coupling on the dynamics of GPEH with SCE is found sensitive to the wind speed.

  3. 75 FR 3888 - Migratory Bird Subsistence Harvest in Alaska; Harvest Regulations for Migratory Birds in Alaska...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-25

    ... Register on November 20, 2009 (74 FR 60228), to propose migratory bird subsistence harvest regulations in... Fish and Wildlife Service 50 CFR Part 92 RIN 1018-AW67 Migratory Bird Subsistence Harvest in Alaska; Harvest Regulations for Migratory Birds in Alaska During the 2010 Season AGENCY: Fish and Wildlife...

  4. Harvesting microalgae grown on wastewater.

    PubMed

    Udom, Innocent; Zaribaf, Behnaz H; Halfhide, Trina; Gillie, Benjamin; Dalrymple, Omatoyo; Zhang, Qiong; Ergas, Sarina J

    2013-07-01

    The costs and life cycle impacts of microalgae harvesting for biofuel production were investigated. Algae were grown in semi-continuous culture in pilot-scale photobioreactors under natural light with anaerobic digester centrate as the feed source. Algae suspensions were collected and the optimal coagulant dosages for metal salts (alum, ferric chloride), cationic polymer (Zetag 8819), anionic polymer (E-38) and natural coagulants (Moringa Oleifera and Opuntia ficus-indica cactus) were determined using jar tests. The relative dewaterability of the algae cake was estimated by centrifugation. Alum, ferric chloride and cationic polymer could all achieve >91% algae recovery at optimal dosages. Life cycle assessment (LCA) and cost analysis results revealed that cationic polymer had the lowest cost but the highest environmental impacts, while ferric chloride had the highest cost and lowest environmental impacts. Based on the LCA results, belt presses are the recommended algae dewatering technology prior to oil extraction. PMID:23648758

  5. Rubber finger stripper harvester for green chile

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Harvest mechanization as a system requires modifying or creating new components including cultivars, production practices, and harvest, transportation and processing plant machinery. New Mexican chile is one of the last segments of the pepper industry to still rely on hand labor. This paper reports ...

  6. A DUST ABATEMENT DEVICE FOR HARVEST

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A prototype device was designed and tested by USDA and New Mexico State University researchers to reduce nuisance dust emissions during nut harvesting. The main goal of the project was to develop a device that could be retrofitted to the many harvesters already in service in the nut producing regio...

  7. An ergonomics approach to citrus harvest mechanization.

    PubMed

    Costa, Simone Emmanuelle Alves; Camarotto, João Alberto

    2012-01-01

    Due to the increase of production costs in manual harvesting, strategies must be developed in order to overcome these effects, such as the attempts in implementing agricultural machines in harvest activities, whether being totally or partially mechanized. This study brings a qualitative and quantitative comparison on the impacts in work conditions and productivity in Brazilian orchards caused by the use of semi-mechanized harvesting systems, such as multiplatforms. The results come from the application of Ergonomic Work Analysis method, which focuses in the activity, quantifying and analyzing times and frequencies of the harvesting cycle, as well as the amount of movements. To achieve this, footage, interviews and a stopwatch were used in the observation 12 pickers' work cycles, six for each method of harvesting. The data interpretation pointed to improvement in working conditions with a reduction in the amount of movements performed by the picker, and increase of up to 60% in productivity with the use of semi-mechanized harvesting. Thus, the found results indicate the viability of this harvesting method. However, other variables must be observed in future studies in order to complete the guidelines for a healthy progress in the area of citrus harvesting in Brazil. PMID:22317498

  8. 7 CFR 1221.12 - Harvest.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE SORGHUM PROMOTION, RESEARCH, AND INFORMATION ORDER Sorghum Promotion, Research, and Information Order Definitions § 1221.12 Harvest. Harvest means combining or threshing sorghum for grain and/or severing the stalks from the land with...

  9. 7 CFR 1221.12 - Harvest.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE SORGHUM PROMOTION, RESEARCH, AND INFORMATION ORDER Sorghum Promotion, Research, and Information Order Definitions § 1221.12 Harvest. Harvest means combining or threshing sorghum for grain and/or severing the stalks from the land with...

  10. 7 CFR 1221.12 - Harvest.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE SORGHUM PROMOTION, RESEARCH, AND INFORMATION ORDER Sorghum Promotion, Research, and Information Order Definitions § 1221.12 Harvest. Harvest means combining or threshing sorghum for grain and/or severing the stalks from the land with...

  11. 7 CFR 1221.12 - Harvest.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE SORGHUM PROMOTION, RESEARCH, AND INFORMATION ORDER Sorghum Promotion, Research, and Information Order Definitions § 1221.12 Harvest. Harvest means combining or threshing sorghum for grain and/or severing the stalks from the land with...

  12. Microbial degradation of post-harvest residues

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Management of post-harvest residues, produced during the green cane harvesting of sugarcane in Louisiana, has become an increasingly important issue for producers, particularly in areas where burning of the residues is banned or restricted. If the residues, which range from 4-8 tonnes per hectare, ...

  13. 7 CFR 1221.12 - Harvest.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE SORGHUM PROMOTION, RESEARCH, AND INFORMATION ORDER Sorghum Promotion, Research, and Information Order Definitions § 1221.12 Harvest. Harvest means combining or threshing sorghum for grain and/or severing the stalks from the land with...

  14. Pepper Harvest Mechanization: Past and Present

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Peppers (Capsicum spp.) include a diverse collection of cultivars produced for a wide variety of end uses. Labor for hand harvest is as much as half of the cost of production. There have been attempts to mechanize pepper harvest since 1965, yet many segments of the industry still depend on hand la...

  15. Biogenesis of light harvesting proteins.

    PubMed

    Dall'Osto, Luca; Bressan, Mauro; Bassi, Roberto

    2015-09-01

    The LHC family includes nuclear-encoded, integral thylakoid membrane proteins, most of which coordinate chlorophyll and xanthophyll chromophores. By assembling with the core complexes of both photosystems, LHCs form a flexible peripheral moiety for enhancing light-harvesting cross-section, regulating its efficiency and providing protection against photo-oxidative stress. Upon its first appearance, LHC proteins underwent evolutionary diversification into a large protein family with a complex genetic redundancy. Such differentiation appears as a crucial event in the adaptation of photosynthetic organisms to changing environmental conditions and land colonization. The structure of photosystems, including nuclear- and chloroplast-encoded subunits, presented the cell with a number of challenges for the control of the light harvesting function. Indeed, LHC-encoding messages are translated in the cytosol, and pre-proteins imported into the chloroplast, processed to their mature size and targeted to the thylakoids where are assembled with chromophores. Thus, a tight coordination between nuclear and plastid gene expression, in response to environmental stimuli, is required to adjust LHC composition during photoacclimation. In recent years, remarkable progress has been achieved in elucidating structure, function and regulatory pathways involving LHCs; however, a number of molecular details still await elucidation. In this review, we will provide an overview on the current knowledge on LHC biogenesis, ranging from organization of pigment-protein complexes to the modulation of gene expression, import and targeting to the photosynthetic membranes, and regulation of LHC assembly and turnover. Genes controlling these events are potential candidate for biotechnological applications aimed at optimizing light use efficiency of photosynthetic organisms. This article is part of a Special Issue entitled: Chloroplast biogenesis. PMID:25687893

  16. Design Methodology of Micro Vibration Energy Harvesters

    NASA Astrophysics Data System (ADS)

    Tanaka, Shuji

    Recently, micro vibration energy harvesters are attracting much attention for wireless sensor applications. To answer the power requirement of practical applications, the design methodology is important. This paper first reviews the fundamental theory of vibration energy harvesting, and then discusses how to design a micro vibration energy harvester at a concept level. For the micro vibration energy harvesters, independent design parameters at the top level are only the mass and stroke of a seismic mass and quality factor, while the frequency and acceleration of vibration input are given parameters determined by the application. The key design point is simply to make the mass and stroke of the seismic mass as large as possible within the available device size. Some case studies based on the theory are also presented. This paper provides a guideline for the development of the micro vibration energy harvesters.

  17. HARVEST, a longitudinal patient record summarizer

    PubMed Central

    Hirsch, Jamie S; Tanenbaum, Jessica S; Lipsky Gorman, Sharon; Liu, Connie; Schmitz, Eric; Hashorva, Dritan; Ervits, Artem; Vawdrey, David; Sturm, Marc; Elhadad, Noémie

    2015-01-01

    Objective To describe HARVEST, a novel point-of-care patient summarization and visualization tool, and to conduct a formative evaluation study to assess its effectiveness and gather feedback for iterative improvements. Materials and methods HARVEST is a problem-based, interactive, temporal visualization of longitudinal patient records. Using scalable, distributed natural language processing and problem salience computation, the system extracts content from the patient notes and aggregates and presents information from multiple care settings. Clinical usability was assessed with physician participants using a timed, task-based chart review and questionnaire, with performance differences recorded between conditions (standard data review system and HARVEST). Results HARVEST displays patient information longitudinally using a timeline, a problem cloud as extracted from notes, and focused access to clinical documentation. Despite lack of familiarity with HARVEST, when using a task-based evaluation, performance and time-to-task completion was maintained in patient review scenarios using HARVEST alone or the standard clinical information system at our institution. Subjects reported very high satisfaction with HARVEST and interest in using the system in their daily practice. Discussion HARVEST is available for wide deployment at our institution. Evaluation provided informative feedback and directions for future improvements. Conclusions HARVEST was designed to address the unmet need for clinicians at the point of care, facilitating review of essential patient information. The deployment of HARVEST in our institution allows us to study patient record summarization as an informatics intervention in a real-world setting. It also provides an opportunity to learn how clinicians use the summarizer, enabling informed interface and content iteration and optimization to improve patient care. PMID:25352564

  18. A novel miniature thermomagnetic energy harvester

    NASA Astrophysics Data System (ADS)

    Chen, Chin-Chung; Chung, Tien-Kan; Cheng, Chi-Cheng; Tseng, Chia-Yuan

    2014-03-01

    Nowadays, thermal-energy-harvesting is an important research topic for powering wireless sensors. Among numerous thermal-energy-harvesting approaches, some researchers demonstrated novel thermomagnetic-energy harvesters to convert a thermal-energy from an ambient temperature-difference to an electrical-output to power the sensors. However, the harvesters are too bulky to be integrated with the sensors embedded in tiny mechanical-structures for some structuralhealth- monitoring applications. Therefore, miniaturized harvesters are needed. Hence, we demonstrate a miniature thermomagnetic-energy harvester. The harvester consists of CuBe-beams, PZT-piezoelectric-sheet, Gd-soft-magnet, NdFeB-hard-magnet, and mechanical-frame. The piezoelectric-sheet and soft-magnet is bounded at fixed-end and freeend of the beams, respectively. The mechanical-frame assembles the beams and hard-magnet. The length×width×thickness of the harvester is 2.5cm×1.7cm×1.5cm. According to this, our harvester is 20-times smaller than the other harvesters. In the initial-state of the energy-harvesting, the beams' free-end is near the cold-side. Thus, the soft-magnet is cooled lower than its curie temperature (Tc) and consequently changed from paramagnetic to ferromagnetic. Therefore, a magnetic-attractive force is produced between the soft-magnet and hard-magnet. Consequently, the beams/soft-magnet are down-pulled toward the hard-magnet fixed on the hot-side. The soft-magnet closing to the hot-side is heated higher than its Tc and subsequently changed to paramagnetic. Consequently, the magnetic-force is eliminated thus the beams are rebounded to the initial-state. Hence, when the harvester is under a temperature-difference, the beams' pulling-down/back process is cyclic. Due to the piezoelectric effect, the piezoelectric-sheet fixed on the beams continuously produces voltage-response. Under the temperature-difference of 29°C, the voltage-response of the harvester is 30.4 mV with an oscillating

  19. Ambient energy harvesting using ferroelectric materials

    NASA Astrophysics Data System (ADS)

    Guyomar, Daniel; Sebald, Gaël; Pruvost, Sébastien; Lallart, Mickaël

    2008-03-01

    Recent progresses in electronics allow powering complex systems using either batteries or environmental energy harvesting. However using batteries raises the problems of limited lifespan and recycling process, leading to the research of other energy sources for mobile electronics. Recent work on Synchronized Switch Harvesting (SSH) shows a significant improvement of energy harvesting from vibrations compared to standard techniques. Nevertheless, harvesting energy from vibrations necessitates that the electromechanical structure has to be driven by mechanical solicitations, which generally have a limited amount of energy. Therefore, for the design of efficient and truly applicable self-powered devices, combining several sources for energy harvesting would be greatly beneficial. Thermal energy is rarely considered due to the difficulty of getting efficient devices. However, the potential of such a source is one of the most important. This paper deals with energy harvesting using either piezoelectric or pyroelectric effect. Theoretical and experimental validations of thermal energy harvesting are presented and discussed. Standard thermodynamic cycles may be adapted in order to improve conversion effectiveness. Experimental converted energy as high as 160 mJ.cm -3.cycle -1 has been measured with a 35°C temperature variation, corresponding to 2.15% of Carnot efficiency.

  20. Approaches to automated protein crystal harvesting

    PubMed Central

    Deller, Marc C.; Rupp, Bernhard

    2014-01-01

    The harvesting of protein crystals is almost always a necessary step in the determination of a protein structure using X-ray crystallographic techniques. However, protein crystals are usually fragile and susceptible to damage during the harvesting process. For this reason, protein crystal harvesting is the single step that remains entirely dependent on skilled human intervention. Automation has been implemented in the majority of other stages of the structure-determination pipeline, including cloning, expression, purification, crystallization and data collection. The gap in automation between crystallization and data collection results in a bottleneck in throughput and presents unfortunate opportunities for crystal damage. Several automated protein crystal harvesting systems have been developed, including systems utilizing microcapillaries, microtools, microgrippers, acoustic droplet ejection and optical traps. However, these systems have yet to be commonly deployed in the majority of crystallography laboratories owing to a variety of technical and cost-related issues. Automation of protein crystal harvesting remains essential for harnessing the full benefits of fourth-generation synchrotrons, free-electron lasers and microfocus beamlines. Furthermore, automation of protein crystal harvesting offers several benefits when compared with traditional manual approaches, including the ability to harvest microcrystals, improved flash-cooling procedures and increased throughput. PMID:24637746

  1. Rainwater Harvesting and Consumption in urban Area

    NASA Astrophysics Data System (ADS)

    Akbar Abbasi, Ali; Tabatabaee, Javad; Ranaee, Ehsan

    2013-04-01

    The soaring rate of urban demand for soft water and the rising cost associated with construction and protection of centralized large-scale water treatment and distribution systems associated with expansion of cities and immigrations of rural population to cities have contributed to increase acceptance of water harvesting systems in urban areas at least. This issue requires special attention in Iran as a developing country in the Middle East semitropical area. In this context, a recent pilot project has been proposed to analyze the performance of rainwater harvesting systems as an answer to some parts of soft water demand in Iranian urban society. A system of rainwater draining and storage has been implemented in a two hectares urban area. Observations and analyses related to runoff quantity and quality have been performed between November 2007 and November 2009 at the basin outlet as well as inside a storage tank which has been set up in the area for water harvesting purposes. The potential of the harvested rainwater to be employed in different consumption contexts has been analyzed in light of national and international standards. Although most of the sampling results support the idea that the quality of harvested water is adequate for any field of consuption, including drinking use (especially during rainfall period of time), a comparison between biological quality evaluation plus turbidity and color of samples with the related standards has led to identify limitations of harvested water usage with particular reference to plant consumptions. Keywords- rainwater harvesting system, runoff, water quality standards

  2. Rainwater harvesting state regulations and technical resources

    SciTech Connect

    Loper, Susan A.

    2015-06-01

    Pacific Northwest National Laboratory (PNNL) conducted in-depth research of state-level rainwater harvesting regulations for the Federal Energy Management Program (FEMP) to help federal agencies strategically identify locations conducive to rainwater harvesting projects. Currently, rainwater harvesting is not regulated by the federal government but rather it is up to individual states to regulate the collection and use of rainwater. There is no centralized information on state-level regulations on rainwater harvesting maintained by a federal agency or outside organization. To fill this information gap, PNNL performed detailed internet searches for each state, which included state agencies, universities, Cooperative Extension Offices, city governments, and related organizations. The state-by-state information on rainwater harvesting regulations was compiled and assembled into an interactive map that is color coded by state regulations. The map provides a visual representation of the general types of rainwater harvesting policies across the country as well as general information on the state programs if applicable. The map allows the user to quickly discern where rainwater harvesting is supported and regulated by the state. This map will be available on the FEMP website by September 2015.

  3. Approaches to automated protein crystal harvesting.

    PubMed

    Deller, Marc C; Rupp, Bernhard

    2014-02-01

    The harvesting of protein crystals is almost always a necessary step in the determination of a protein structure using X-ray crystallographic techniques. However, protein crystals are usually fragile and susceptible to damage during the harvesting process. For this reason, protein crystal harvesting is the single step that remains entirely dependent on skilled human intervention. Automation has been implemented in the majority of other stages of the structure-determination pipeline, including cloning, expression, purification, crystallization and data collection. The gap in automation between crystallization and data collection results in a bottleneck in throughput and presents unfortunate opportunities for crystal damage. Several automated protein crystal harvesting systems have been developed, including systems utilizing microcapillaries, microtools, microgrippers, acoustic droplet ejection and optical traps. However, these systems have yet to be commonly deployed in the majority of crystallography laboratories owing to a variety of technical and cost-related issues. Automation of protein crystal harvesting remains essential for harnessing the full benefits of fourth-generation synchrotrons, free-electron lasers and microfocus beamlines. Furthermore, automation of protein crystal harvesting offers several benefits when compared with traditional manual approaches, including the ability to harvest microcrystals, improved flash-cooling procedures and increased throughput. PMID:24637746

  4. Autotransplantation donor tooth site harvesting using piezosurgery

    PubMed Central

    Ylikontiola, Leena P.; Sándor, George K.

    2016-01-01

    Background: The harvesting of a tooth as a candidate for tooth autotransplantation requires that the delicate dental tissues around the tooth be minimally traumatized. This is especially so for the periradicular tissues of the tooth root and the follicular tissues surrounding the crown. The aim of this report is to describe the use of piezosurgery as an attempt at morbidity reduction in the harvesting of teeth for autotransplantation. Methods: A piezosurgical handpiece and its selection of tips were easily adapted to allow the harvesting and delivery of teeth for autotransplantation purposes. Results: Twenty premolar teeth were harvested using a piezosurgical device. The harvested teeth were subsequently successfully autotransplanted. All twenty teeth healed in a satisfactory manner without excessive mobility or ankyloses. Conclusions: Piezosurgery avoids some of the traumatic aspects of harvesting teeth and removing bone which are associated with thermal damage from the use of conventional rotary instruments or saws. Piezosurgery can be adapted to facilitate the predictable harvesting of teeth for autotransplantation purposes. PMID:27563612

  5. Energy harvesting through wind excitation of a piezoelectric flag-like harvester

    NASA Astrophysics Data System (ADS)

    Truitt, Andrew

    This study seeks to propose a novel approach to wind-based piezoelectric energy harvesting. A brief literature review of energy harvesting followed by a discussion of piezoelectric system dynamics is offered. Biomedical applications for piezoelectric energy harvesting are then presented offering a segue into fluid based energy harvesting. Fluid based energy harvesting is a relatively young subfield within piezoelectric energy harvesting, but it is increasingly pursued due to the ubiquitous nature of the excitation source as well as the strong correlation with other types of excitation. Vortex-induced vibrations (VIV), as well as vibrations induced by bluff bodies, and the effect of their shape on potential gains have been investigated. The interactions of VIVs on a flag-like membrane form the foundation for the piezoelectric energy harvester in this study. Polyvinylidene fluoride (PVDF) piezoelectric energy harvesters are chosen due to their desirable flexibility. Modeling of flag-like systems is review followed by system modeling of a PVDF piezoelectric flag. Numerical and experimental results from the PVDF flag-like piezoelectric energy harvester are generated and compared. A maximum power output of 1.5 mW is achieved with the flag-like system which is competitive when compared to power output and energy density levels of other studies. The power output of this system provides concrete evidence for the effective use of not only this type of energy harvester system model but also for the use of PVDFs in wind-based applications.

  6. Damage induced dissipation in electroactive polymer harvesters

    NASA Astrophysics Data System (ADS)

    Colonnelli, S.; Saccomandi, G.; Zurlo, G.

    2014-10-01

    Electromechanical harvesters based on dielectric electroactive polymers are promising devices for the production of electrical energy by the conversion of abundant sources of mechanical work available in Nature. However, severe limitations to the performance of these devices arise from various sources of dissipation and failure of the polymeric material. By making use of an energetic approach, we establish a direct and quantitative connection between the Mullins effect taking place in the polymeric material and the harvesting efficiency, showing the prominent role of rate-independent effects in the hysteretic behavior of electromechanical harvesters.

  7. The effects of harvest on waterfowl populations

    USGS Publications Warehouse

    Cooch, Evan G.; Guillemain, Matthieu; Boomer, G Scott; Lebreton, Jean-Dominique; Nichols, James D.

    2014-01-01

    Overall, there is substantial uncertainty about system dynamics, about the impacts of potential management and conservation decisions on those dynamics, and how to optimise management decisions in the presence of such uncertainties. Such relationships are unlikely to be stationary over space or time, and selective harvest of some individuals can potentially alter life history allocation of resources over time – both of which will potentially influence optimal harvest strategies. These sources of variation and uncertainty argue for the use of adaptive approaches to waterfowl harvest management.

  8. Hybrid piezoelectric energy harvesting transducer system

    NASA Technical Reports Server (NTRS)

    Xu, Tian-Bing (Inventor); Jiang, Xiaoning (Inventor); Su, Ji (Inventor); Rehrig, Paul W. (Inventor); Hackenberger, Wesley S. (Inventor)

    2008-01-01

    A hybrid piezoelectric energy harvesting transducer system includes: (a) first and second symmetric, pre-curved piezoelectric elements mounted separately on a frame so that their concave major surfaces are positioned opposite to each other; and (b) a linear piezoelectric element mounted separately on the frame and positioned between the pre-curved piezoelectric elements. The pre-curved piezoelectric elements and the linear piezoelectric element are spaced from one another and communicate with energy harvesting circuitry having contact points on the frame. The hybrid piezoelectric energy harvesting transducer system has a higher electromechanical energy conversion efficiency than any known piezoelectric transducer.

  9. Energy harvesting via ferrofluidic induction

    NASA Astrophysics Data System (ADS)

    Monroe, J. G.; Vasquez, Erick S.; Aspin, Zachary S.; Fairley, John D.; Walters, Keisha B.; Berg, Matthew J.; Thompson, Scott M.

    2015-05-01

    A series of experiments were conducted to investigate and characterize the concept of ferrofluidic induction - a process for generating electrical power via cyclic oscillation of ferrofluid (iron-based nanofluid) through a solenoid. Experimental parameters include: number of bias magnets, magnet spacing, solenoid core, fluid pulse frequency and ferrofluid-particle diameter. A peristaltic pump was used to cyclically drive two aqueous ferrofluids, consisting of 7-10 nm iron-oxide particles and commercially-available hydroxyl-coated magnetic beads (~800 nm), respectively. The solutions were pulsated at 3, 6, and 10 Hz through 3.2 mm internal diameter Tygon tubing. A 1000 turn copper-wire solenoid was placed around the tube 45 cm away from the pump. The experimental results indicate that the ferrofluid is capable of inducing a maximum electric potential of approximately +/- 20 μV across the solenoid during its cyclic passage. As the frequency of the pulsating flow increased, the ferro-nanoparticle diameter increased, or the bias magnet separation decreased, the induced voltage increased. The type of solenoid core material (copper or plastic) did not have a discernible effect on induction. These results demonstrate the feasibility of ferrofluidic induction and provide insight into its dependence on fluid/flow parameters. Such fluidic/magneto-coupling can be exploited for energy harvesting and/or conversion system design for a variety of applications.

  10. Thermal Energy Harvesting from Wildlife

    NASA Astrophysics Data System (ADS)

    Woias, P.; Schule, F.; Bäumke, E.; Mehne, P.; Kroener, M.

    2014-11-01

    In this paper we present the measurement of temperature differences between the ambient air and the body temperature of a sheep (Heidschnucke) and its applicability for thermoelectric energy harvesting from livestock, demonstrated via the test of a specially tailored TEG system in a real-life experiment. In three measurement campaigns average temperature differences were found between 2.5 K and 3.5 K. Analytical models and FEM simulations were carried out to determine the actual thermal resistance of the sheep's fur from comparisons with the temperature measurements. With these data a thermoelectric (TEG) generator was built in a thermally optimized housing with adapted heats sink. The whole TEG system was mounted to a collar, including a data logger for recording temperature and TEG voltage. First measurements at the neck of a sheep were accomplished, with a calculated maximal average power output of 173 μW at the TEG. Taking the necessity of a low-voltage step-up converter into account, an electric output power of 54 μW is available which comes close to the power consumption of a low-power VHF tracking system.

  11. 50 CFR 300.112 - Harvesting permits.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... ownership is not reported, the violation is chargeable to the previous owner. Title 15 CFR part 904 governs... subject to the jurisdiction of the United States to harass, capture, harm, kill, harvest, or import...

  12. 50 CFR 300.112 - Harvesting permits.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... ownership is not reported, the violation is chargeable to the previous owner. Title 15 CFR part 904 governs... subject to the jurisdiction of the United States to harass, capture, harm, kill, harvest, or import...

  13. Adaptive learning algorithms for vibration energy harvesting

    NASA Astrophysics Data System (ADS)

    Ward, John K.; Behrens, Sam

    2008-06-01

    By scavenging energy from their local environment, portable electronic devices such as MEMS devices, mobile phones, radios and wireless sensors can achieve greater run times with potentially lower weight. Vibration energy harvesting is one such approach where energy from parasitic vibrations can be converted into electrical energy through the use of piezoelectric and electromagnetic transducers. Parasitic vibrations come from a range of sources such as human movement, wind, seismic forces and traffic. Existing approaches to vibration energy harvesting typically utilize a rectifier circuit, which is tuned to the resonant frequency of the harvesting structure and the dominant frequency of vibration. We have developed a novel approach to vibration energy harvesting, including adaptation to non-periodic vibrations so as to extract the maximum amount of vibration energy available. Experimental results of an experimental apparatus using an off-the-shelf transducer (i.e. speaker coil) show mechanical vibration to electrical energy conversion efficiencies of 27-34%.

  14. Manual harvesting of high population Leucaena stands

    SciTech Connect

    Pecson, R.D.; Van Den Beldt, R.J.

    1983-01-01

    Five-year-old giant Leucaena leucocephala, planted at spacing 1x0.5 m, were harvested using bolos (Filipino machetes) and chainsaws. For felling alone, chainsaws took 35% less time than bolos. For the total harvest including delimbing and hauling an average 20 m to the edge of the stand, chainsaws took 20% less time than bolos. Assuming chainsaws are economically viable, it may be advisable to fell with chainsaws in advance of bolo teams that buck and haul. 2 references.

  15. Study on Pyroelectric Harvesters with Various Geometry.

    PubMed

    Siao, An-Shen; Chao, Ching-Kong; Hsiao, Chun-Ching

    2015-01-01

    Pyroelectric harvesters convert time-dependent temperature variations into electric current. The appropriate geometry of the pyroelectric cells, coupled with the optimal period of temperature fluctuations, is key to driving the optimal load resistance, which enhances the performance of pyroelectric harvesters. The induced charge increases when the thickness of the pyroelectric cells decreases. Moreover, the induced charge is extremely reduced for the thinner pyroelectric cell when not used for the optimal period. The maximum harvested power is achieved when a 100 μm-thick PZT (Lead zirconate titanate) cell is used to drive the optimal load resistance of about 40 MΩ. Moreover, the harvested power is greatly reduced when the working resistance diverges even slightly from the optimal load resistance. The stored voltage generated from the 75 μm-thick PZT cell is less than that from the 400 μm-thick PZT cell for a period longer than 64 s. Although the thinner PZT cell is advantageous in that it enhances the efficiency of the pyroelectric harvester, the much thinner 75 μm-thick PZT cell and the divergence from the optimal period further diminish the performance of the pyroelectric cell. Therefore, the designers of pyroelectric harvesters need to consider the coupling effect between the geometry of the pyroelectric cells and the optimal period of temperature fluctuations to drive the optimal load resistance. PMID:26270666

  16. Hybrid energy harvesting using active thermal backplane

    NASA Astrophysics Data System (ADS)

    Kim, Hyun-Wook; Lee, Dong-Gun

    2016-04-01

    In this study, we demonstrate the concept of a new hybrid energy harvesting system by combing solar cells with magneto-thermoelectric generator (MTG, i.e., thermal energy harvesting). The silicon solar cell can easily reach high temperature under normal operating conditions. Thus the heated solar cell becomes rapidly less efficient as the temperature of solar cell rises. To increase the efficiency of the solar cell, air or water-based cooling system is used. To surpass conventional cooling devices requiring additional power as well as large working space for air/water collectors, we develop a new technology of pairing an active thermal backplane (ATB) to solar cell. The ATB design is based on MTG technology utilizing the physics of the 2nd order phase transition of active ferromagnetic materials. The MTG is cost-effective conversion of thermal energy to electrical energy and is fundamentally different from Seebeck TEG devices. The ATB (MTG) is in addition to being an energy conversion system, a very good conveyor of heat through both conduction and convection. Therefore, the ATB can provide dual-mode for the proposed hybrid energy harvesting. One is active convective and conductive cooling for heated solar cell. Another is active thermal energy harvesting from heat of solar cell. These novel hybrid energy harvesting device have potentially simultaneous energy conversion capability of solar and thermal energy into electricity. The results presented can be used for better understanding of hybrid energy harvesting system that can be integrated into commercial applications.

  17. Study on Pyroelectric Harvesters with Various Geometry

    PubMed Central

    Siao, An-Shen; Chao, Ching-Kong; Hsiao, Chun-Ching

    2015-01-01

    Pyroelectric harvesters convert time-dependent temperature variations into electric current. The appropriate geometry of the pyroelectric cells, coupled with the optimal period of temperature fluctuations, is key to driving the optimal load resistance, which enhances the performance of pyroelectric harvesters. The induced charge increases when the thickness of the pyroelectric cells decreases. Moreover, the induced charge is extremely reduced for the thinner pyroelectric cell when not used for the optimal period. The maximum harvested power is achieved when a 100 μm-thick PZT (Lead zirconate titanate) cell is used to drive the optimal load resistance of about 40 MΩ. Moreover, the harvested power is greatly reduced when the working resistance diverges even slightly from the optimal load resistance. The stored voltage generated from the 75 μm-thick PZT cell is less than that from the 400 μm-thick PZT cell for a period longer than 64 s. Although the thinner PZT cell is advantageous in that it enhances the efficiency of the pyroelectric harvester, the much thinner 75 μm-thick PZT cell and the divergence from the optimal period further diminish the performance of the pyroelectric cell. Therefore, the designers of pyroelectric harvesters need to consider the coupling effect between the geometry of the pyroelectric cells and the optimal period of temperature fluctuations to drive the optimal load resistance. PMID:26270666

  18. Endoscopic vein harvesting: technique, outcomes, concerns & controversies

    PubMed Central

    Sarang, Zubair

    2013-01-01

    The choice of the graft conduit for coronary artery bypass grafting (CABG) has significant implications both in the short- and long-term. The patency of a coronary conduit is closely associated with an uneventful postoperative course, better long-term patient survival and superior freedom from re-intervention. The internal mammary artery is regarded as the primary conduit for CABG patients, given its association with long-term patency and survival. However, long saphenous vein (LSV) continues to be utilized universally as patients presenting for CABG often have multiple coronary territories requiring revascularization. Traditionally, the LSV has been harvested by creating incisions from the ankle up to the groin termed open vein harvesting (OVH). However, such harvesting methods are associated with incisional pain and leg wound infections. In addition, patients find such large incisions to be cosmetically unappealing. These concerns regarding wound morbidity and patient satisfaction led to the emergence of endoscopic vein harvesting (EVH). Published experience comparing OVH with EVH suggests decreased wound related complications, improved patient satisfaction, shorter hospital stay, and reduced postoperative pain at the harvest site following EVH. Despite these reported advantages concerns regarding risk of injury at the time of harvest with its potential detrimental effect on vein graft patency and clinical outcomes have prevented universal adoption of EVH. This review article provides a detailed insight into the technical aspects, outcomes, concerns, and controversies associated with EVH. PMID:24251019

  19. Harvesting Vibrational Energy Using Material Work Functions

    PubMed Central

    Varpula, Aapo; Laakso, Sampo J.; Havia, Tahvo; Kyynäräinen, Jukka; Prunnila, Mika

    2014-01-01

    Vibration energy harvesters scavenge energy from mechanical vibrations to energise low power electronic devices. In this work, we report on vibration energy harvesting scheme based on the charging phenomenon occurring naturally between two bodies with different work functions. Such work function energy harvester (WFEH) is similar to electrostatic energy harvester with the fundamental distinction that neither external power supplies nor electrets are needed. A theoretical model and description of different operation modes of WFEHs are presented. The WFEH concept is tested with macroscopic experiments, which agree well with the model. The feasibility of miniaturizing WFEHs is shown by simulating a realistic MEMS device. The WFEH can be operated as a charge pump that pushes charge and energy into an energy storage element. We show that such an operation mode is highly desirable for applications and that it can be realised with either a charge shuttle or with switches. The WFEH is shown to give equal or better output power in comparison to traditional electrostatic harvesters. Our findings indicate that WFEH has great potential in energy harvesting applications. PMID:25348004

  20. Harvesting Vibrational Energy Using Material Work Functions

    NASA Astrophysics Data System (ADS)

    Varpula, Aapo; Laakso, Sampo J.; Havia, Tahvo; Kyynäräinen, Jukka; Prunnila, Mika

    2014-10-01

    Vibration energy harvesters scavenge energy from mechanical vibrations to energise low power electronic devices. In this work, we report on vibration energy harvesting scheme based on the charging phenomenon occurring naturally between two bodies with different work functions. Such work function energy harvester (WFEH) is similar to electrostatic energy harvester with the fundamental distinction that neither external power supplies nor electrets are needed. A theoretical model and description of different operation modes of WFEHs are presented. The WFEH concept is tested with macroscopic experiments, which agree well with the model. The feasibility of miniaturizing WFEHs is shown by simulating a realistic MEMS device. The WFEH can be operated as a charge pump that pushes charge and energy into an energy storage element. We show that such an operation mode is highly desirable for applications and that it can be realised with either a charge shuttle or with switches. The WFEH is shown to give equal or better output power in comparison to traditional electrostatic harvesters. Our findings indicate that WFEH has great potential in energy harvesting applications.

  1. Internal resonance for nonlinear vibration energy harvesting

    NASA Astrophysics Data System (ADS)

    Cao, D. X.; Leadenham, S.; Erturk, A.

    2015-11-01

    The transformation of waste vibration energy into low-power electricity has been heavily researched over the last decade to enable self-sustained wireless electronic components. Monostable and bistable nonlinear oscillators have been explored by several research groups in an effort to enhance the frequency bandwidth of operation. Linear two-degree-of-freedom (2-DOF) configurations as well as the combination of a nonlinear single-DOF harvester with a linear oscillator to constitute a nonlinear 2-DOF harvester have also been explored to develop broadband energy harvesters. In the present work, the concept of nonlinear internal resonance in a continuous frame structure is explored for broadband energy harvesting. The L-shaped beam-mass structure with quadratic nonlinearity was formerly studied in the nonlinear dynamics literature to demonstrate modal energy exchange and the saturation phenomenon when carefully tuned for two-to-one internal resonance. In the current effort, piezoelectric coupling and an electrical load are introduced, and electromechanical equations of the L-shaped energy harvester are employed to explore primary resonance behaviors around the first and the second linear natural frequencies for bandwidth enhancement. Simulations using approximate analytical frequency response equations as well as numerical solutions reveal significant bandwidth enhancement as compared to a typical linear 2-DOF counterpart. Vibration and voltage responses are explored, and the effects of various system parameters on the overall dynamics of the internal resonance-based energy harvesting system are reported.

  2. Harvesting electricity from human hair.

    PubMed

    Tulachan, Brindan; Singh, Sushil K; Philip, Deepu; Das, Mainak

    2016-01-01

    continuously hydrating the polymer with water vapor, we prolonged the process. If this interesting aspect of polymer is exploited further and fine tuned, then it will open new avenues for development of sophisticated polymer-based systems, which could be used to harvest electricity from waste heat. PMID:27319058

  3. Microalgae harvesting and processing: a literature review

    SciTech Connect

    Shelef, G.; Sukenik, A.; Green, M.

    1984-08-01

    The objective of this report is to present a discussion of the literature review performed on methods of harvesting microalgae. There is no single best method of harvesting microalgae. The choice of preferable harvesting technology depends on algae species, growth medium, algae production, end product, and production cost benefit. Algae size is an important factor since low-cost filtration procedures are presently applicable only for harvesting fairly large microalgae. Small microalgae should be flocculated into larger bodies that can be harvested by one of the methods mentioned above. However, the cells' mobility affects the flocculation process, and addition of nonresidual oxidants to stop the mobility should be considered to aid flocculation. The decision between sedimentation or flotation methods depends on the density difference between the algae cell and the growth medium. For oil-laden algae with low cell density, flotation technologies should be considered. Moreover, oxygen release from algae cells and oxygen supersaturation conditions in growth medium support the use of flotation methods. If high-quality algae are to be produced for human consumption, continuous harvesting by solid ejecting or nozzle-type disc centrifuges is recommended. These centrifuges can easily be cleaned and sterilized. They are suitable for all types of microalgae, but their high operating costs should be compared with the benefits from their use. Another basic criterion for selecting the suitable harvesting procedure is the final algae paste concentration required for the next process. Solids requirements up to 30% can be attained by established dewatering processes. For more concentrated solids, drying methods are required. The various systems for algae drying differ both in the extent of capital investment and the energy requirements. Selection of the drying method depends on the scale of operation and the use for which the dried product is intended.

  4. 78 FR 75321 - Migratory Bird Subsistence Harvest in Alaska; Harvest Regulations for Migratory Birds in Alaska...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-11

    ...The U.S. Fish and Wildlife Service (Service or we) proposes migratory bird subsistence harvest regulations in Alaska for the 2014 season. These regulations would enable the continuation of customary and traditional subsistence uses of migratory birds in Alaska and prescribe regional information on when and where the harvesting of birds may occur. These regulations were developed under a......

  5. Double synchronized switch harvesting (DSSH): a new energy harvesting scheme for efficient energy extraction.

    PubMed

    Lallart, Mickaël; Garbuio, Lauric; Petit, Lionel; Richard, Claude; Guyomar, Daniel

    2008-10-01

    This paper presents a new technique for optimized energy harvesting using piezoelectric microgenerators called double synchronized switch harvesting (DSSH). This technique consists of a nonlinear treatment of the output voltage of the piezoelectric element. It also integrates an intermediate switching stage that ensures an optimal harvested power whatever the load connected to the microgenerator. Theoretical developments are presented considering either constant vibration magnitude, constant driving force, or independent extraction. Then experimental measurements are carried out to validate the theoretical predictions. This technique exhibits a constant output power for a wide range of load connected to the microgenerator. In addition, the extracted power obtained using such a technique allows a gain up to 500% in terms of maximal power output compared with the standard energy harvesting method. It is also shown that such a technique allows a fine-tuning of the trade-off between vibration damping and energy harvesting. PMID:18986861

  6. Acquiring geographical data with web harvesting

    NASA Astrophysics Data System (ADS)

    Dramowicz, K.

    2016-04-01

    Many websites contain very attractive and up to date geographical information. This information can be extracted, stored, analyzed and mapped using web harvesting techniques. Poorly organized data from websites are transformed with web harvesting into a more structured format, which can be stored in a database and analyzed. Almost 25% of web traffic is related to web harvesting, mostly while using search engines. This paper presents how to harvest geographic information from web documents using the free tool called the Beautiful Soup, one of the most commonly used Python libraries for pulling data from HTML and XML files. It is a relatively easy task to process one static HTML table. The more challenging task is to extract and save information from tables located in multiple and poorly organized websites. Legal and ethical aspects of web harvesting are discussed as well. The paper demonstrates two case studies. The first one shows how to extract various types of information about the Good Country Index from the multiple web pages, load it into one attribute table and map the results. The second case study shows how script tools and GIS can be used to extract information from one hundred thirty six websites about Nova Scotia wines. In a little more than three minutes a database containing one hundred and six liquor stores selling these wines is created. Then the availability and spatial distribution of various types of wines (by grape types, by wineries, and by liquor stores) are mapped and analyzed.

  7. A self-adaptive energy harvesting system

    NASA Astrophysics Data System (ADS)

    Hoffmann, D.; Willmann, A.; Hehn, T.; Folkmer, B.; Manoli, Y.

    2016-03-01

    This paper reports on a self-adaptive energy harvesting system, which is able to adapt its eigenfrequency to the operating conditions of power units. The power required for frequency tuning is delivered by the energy harvester itself. The tuning mechanism is based on a magnetic concept and incorporates a circular tuning magnet and a coupling magnet. In this manner, both coupling modes (attractive and repulsive) can be utilized for tuning the eigenfrequency of the energy harvester. The tuning range and its center frequency can be tailored to the application by careful design of the spring stiffness and the gap between tuning magnet and coupling magnet. Experimental results demonstrate that, in contrast to a conventional non-tunable vibration energy harvester, the net power can be significantly increased if a self-adaptive system is utilized, although additional power is required for regular adjustments of the eigenfrequency. The outcome confirms that active tuning is a real and practical option to extend the operational frequency range and to increase the net power of a conventional vibration energy harvester.

  8. A novel bistable energy harvesting concept

    NASA Astrophysics Data System (ADS)

    Scarselli, G.; Nicassio, F.; Pinto, F.; Ciampa, F.; Iervolino, O.; Meo, M.

    2016-05-01

    Bistable energy harvesting has become a major field of research due to some unique features for converting mechanical energy into electrical power. When properly loaded, bistable structures snap-through from one stable configuration to another, causing large strains and consequently power generation. Moreover, bistable structures can harvest energy across a broad-frequency bandwidth due to their nonlinear characteristics. Despite the fact that snap-through may be triggered regardless of the form or frequency of exciting vibration, the external force must reach a specific snap-through activation threshold value to trigger the transition from one stable state to another. This aspect is a limiting factor for realistic vibration energy harvesting application with bistable devices. This paper presents a novel power harvesting concept for bistable composites based on a ‘lever effect’ aimed at minimising the activation force to cause the snap through by choosing properly the bistable structures’ constraints. The concept was demonstrated with the help of numerical simulation and experimental testing. The results showed that the actuation force is one order of magnitude smaller (3%-6%) than the activation force of conventionally constrained bistable devices. In addition, it was shown that the output voltage was higher than the conventional configuration, leading to a significant increase in power generation. This novel concept could lead to a new generation of more efficient bistable energy harvesters for realistic vibration environments.

  9. A hydrostatic pressure-cycle energy harvester

    NASA Astrophysics Data System (ADS)

    Shafer, Michael W.; Hahn, Gregory; Morgan, Eric

    2015-04-01

    There have been a number of new applications for energy harvesting with the ever-decreasing power consumption of microelectronic devices. In this paper we explore a new area of marine animal energy harvesting for use in powering tags known as bio-loggers. These devices record data about the animal or its surroundings, but have always had limited deployment times due to battery depletion. Reduced solar irradiance below the water's surface provides the impetus to explore other energy harvesting concepts beyond solar power for use on marine animals. We review existing tag technologies in relation to this application, specifically relating to energy consumption. Additionally, we propose a new idea for energy harvesting, using hydrostatic pressure changes as a source for energy production. We present initial testing results of a bench-top model and show that the daily energy harvesting potential from this technology can meet or exceed that consumed by current marine bio-logging tags. The application of this concept in the arena of bio-logging technology could substantially increase bio-logger deployment lifetimes, allowing for longitudinal studies over the course of multiple breeding and/or migration cycles.

  10. Triboelectric Nanogenerators for Blue Energy Harvesting.

    PubMed

    Khan, Usman; Kim, Sang-Woo

    2016-07-26

    Blue energy in the form of ocean waves offers an enormous energy resource. However, it has yet to be fully exploited in order to make it available for the use of mankind. Blue energy harvesting is a challenging task as the kinetic energy from ocean waves is irregular in amplitude and is at low frequencies. Though electromagnetic generators (EMGs) are well-known for harvesting mechanical kinetic energies, they have a crucial limitation for blue energy conversion. Indeed, the output voltage of EMGs can be impractically low at the low frequencies of ocean waves. In contrast, triboelectric nanogenerators (TENGs) are highly suitable for blue energy harvesting as they can effectively harvest mechanical energies from low frequencies (<1 Hz) to relatively high frequencies (∼kHz) and are also low-cost, lightweight, and easy to fabricate. Several important steps have been taken by Wang's group to develop TENG technology for blue energy harvesting. In this Perspective, we describe some of the recent progress and also address concerns related to durable packaging of TENGs in consideration of harsh marine environments and power management for an efficient power transfer and distribution for commercial applications. PMID:27408982

  11. MEMS electromagnetic energy harvesters with multiple resonances

    NASA Astrophysics Data System (ADS)

    Nelatury, Sudarshan R.; Gray, Robert

    2014-06-01

    There is going on a flurry of research activity in the development of effcient energy harvesters from all branches of energy conversion. The need for developing self-powered wireless sensors and actuators to be employed in unmanned combat vehicles also seems to grow steadily. These vehicles are inducted into perilous war zones for silent watch missions. Energy management is sometimes carried out using misson-aware energy expenditure strategies. Also, when there is a requirement for constant monitoring of events, the sensors and the subsystems of combat vehicles require energy harvesters that can operate over a discrete set of spot frequencies. This paper attempts to review some of the recent techniques and the energy harvesting devices based on electromagnetic and electromechanical principles. In particular, we shall discuss the design and performance of a MEMS-harvester that exhibits multiple resonances. Frequency response of a simulated electromagnetic harvester is plotted. It has three dominant peaks at three different resonant frequencies. Variation in the load power in the normalized units as a function of load is found, which determines the matched load resistance.

  12. Achieving multiple benefits from stormwater harvesting.

    PubMed

    Mitchell, V G; Deletic, A; Fletcher, T D; Hatt, B E; McCarthy, D T

    2007-01-01

    As the concept of integrated urban water management is incorporated into the practice of urban water servicing, new options, such as stormwater harvesting, which can have multiple benefits, are of increasing interest. The multi-functional benefits of stormwater harvesting include the potential to enhance urban stream health through improvements to the flow regime as well as providing a valuable water supply source. This paper synthesises a current research programme being undertaken to assess the viability of, and develop recommendations for, stormwater harvesting. The design of the collection, treatment, storage, flood protection, and distribution components of an integrated system are each discussed, along with the environmental flow consequences of urban stormwater harvesting. The incorporation of swales and biofilters into the collection system was not found to lead to significant exfiltration and evaporation losses in most circumstances and so can be employed as part of the treatment train. Further treatment can be provided by WSUD-type biophysical measures such as ponds, wetlands or novelly designed biofilters or physio-chemical treatment processes. Depending on the design, the stormwater storage component may or may not provide flood protection. In many circumstances, the storage capacity requirements are not considered to be a barrier to stormwater harvesting. PMID:17425080

  13. Plucked piezoelectric bimorphs for energy harvesting applications

    NASA Astrophysics Data System (ADS)

    Pozzi, Michele; Zhu, Meiling

    2011-06-01

    The modern drive towards mobility and wireless devices is motivating intense research in energy harvesting (EH) technologies. In an effort to reduce the battery burden of people, we are investigating a novel piezoelectric wearable energy harvester. As piezoelectric EH is significantly more effective at high frequencies, in opposition to the characteristically low-frequency human activities, we propose the use of an up-conversion strategy analogous to the pizzicato musical technique. In order to guide the design of such harvester, we have modelled with Finite Elements (FE) the response and power generation of a piezoelectric bimorph while it is "plucked", i.e. deflected, then released and permitted to vibrate freely. An experimental rig has been devised and set up to reproduce the action of the bimorph in the harvester. Measurements of the voltage output and the energy dissipated across a series resistor are reported and compared with the FE predictions. As the novel harvester will feature a number of bimorphs, each plucked tens of times per step, we predict a total power output of several mW, with imperceptible effect on the wearer's gait.

  14. Acceleration-assisted entanglement harvesting and rangefinding

    NASA Astrophysics Data System (ADS)

    Salton, Grant; Mann, Robert B.; Menicucci, Nicolas C.

    2015-03-01

    We study entanglement harvested from a quantum field through local interaction with Unruh-DeWitt detectors undergoing linear acceleration. The interactions allow entanglement to be swapped locally from the field to the detectors. We find an enhancement in the entanglement harvesting by two detectors with anti-parallel acceleration over those with inertial motion. This enhancement is characterized by the presence of entanglement between two detectors that would otherwise maintain a separable state in the absence of relativistic motion (with the same distance of closest approach in both cases). We also find that entanglement harvesting is degraded for two detectors undergoing parallel acceleration in the same way as for two static, comoving detectors in a de Sitter universe. This degradation is known to be different from that of two inertial detectors in a thermal bath. We comment on the physical origin of the harvested entanglement and present three methods for determining distance between two detectors using properties of the harvested entanglement. Information about the separation is stored nonlocally in the joint state of the accelerated detectors after the interaction; a single detector alone contains none. We also find an example of entanglement sudden death exhibited in parameter space.

  15. Enhanced energy harvesting in commercial ferroelectric materials

    NASA Astrophysics Data System (ADS)

    Patel, Satyanarayan; Chauhan, Aditya; Vaish, Rahul

    2014-04-01

    Ferroelectric materials are used in a number of applications ranging from simple sensors and actuators to ferroelectric random access memories (FRAMs), transducers, health monitoring system and microelectronics. The multiphysical coupling ability possessed by these materials has been established to be useful for energy harvesting applications. However, conventional energy harvesting techniques employing ferroelectric materials possess low energy density. This has prevented the successful commercialization of ferroelectric based energy harvesting systems. In this context, the present study aims at proposing a novel approach for enhanced energy harvesting using commercially available ferroelectric materials. This technique was simulated to be used for two commercially available piezoelectric materials namely PKI-552 and APCI-840, soft and hard lead-zirconate-titanate (PZT) pervoskite ceramics, respectively. It was observed that a maximum energy density of 348 kJm-3cycle-1 can be obtained for cycle parameters of (0-1 ton compressive stress and 1-25 kV.cm-1 electric field) using APCI-840. The reported energy density is several hundred times larger than the maximum energy density reported in the literature for vibration harvesting systems.

  16. Ecological impacts of energy-wood harvests: lessons from whole-tree harvesting and natural disturbance

    USGS Publications Warehouse

    Berger, Alaina L.; Palik, Brian; D'Amato, Anthony W.; Fraver, Shawn; Bradford, John B.; Nislow, Keith H.; King, David; Brooks, Robert T.

    2013-01-01

    Recent interest in using forest residues and small-diameter material for biofuels is generating a renewed focus on harvesting impacts and forest sustainability. The rich legacy of research from whole-tree harvesting studies can be examined in light of this interest. Although this research largely focused on consequences for forest productivity, in particular carbon and nutrient pools, it also has relevance for examining potential consequences for biodiversity and aquatic ecosystems. This review is framed within a context of contrasting ecosystem impacts from whole-tree harvesting because it represents a high level of biomass removal. Although whole-tree harvesting does not fully use the nonmerchantable biomass available, it indicates the likely direction and magnitude of impacts that can occur through energy-wood harvesting compared with less-intensive conventional harvesting and to dynamics associated with various natural disturbances. The intent of this comparison is to gauge the degree of departure of energy-wood harvesting from less intensive conventional harvesting. The review of the literature found a gradient of increasing departure in residual structural conditions that remained in the forest when conventional and whole-tree harvesting was compared with stand-replacing natural disturbance. Important stand- and landscape-level processes were related to these structural conditions. The consequence of this departure may be especially potent because future energy-wood harvests may more completely use a greater range of forest biomass at potentially shortened rotations, creating a great need for research that explores the largely unknown scale of disturbance that may apply to our forest ecosystems.

  17. Low Cost Mechanical Aid for Rice Harvesting

    NASA Astrophysics Data System (ADS)

    Bora, Ganesh C.; Hansen, Gunner K.

    A small engine-powered harvesting aid for small area rice farmers was developed. The machine was a modified brush cutter. The original cutter blade was replaced by a 25 cm diameter circular saw blade. A metal plate and rubber guard assembly was fitted behind the blade on the handle to guide the cut stalk to the left side. The machine performed well in the field conditions with a field capacity of 0.51 ha day-1 consuming 0.25 L of fuel in an hour. It was 7.8 times faster than manual harvesting though the field loss was around 2.3% as against 1% in manual harvesting. The break-even area was 1 ha and the payback period for the investment was one year. The machine should be affordable to low income farmers in developing countries and women would also be able to taste the fruits of mechanization.

  18. Subwavelength resonant antennas enhancing electromagnetic energy harvesting

    NASA Astrophysics Data System (ADS)

    Oumbe Tekam, Gabin; Ginis, Vincent; Seetharamdoo, Divitha; Danckaert, Jan

    2016-04-01

    In this work, an electromagnetic energy harvester operating at microwave frequencies is designed based on a cut- wire metasurface. This metamaterial is known to contain a quasistatic electric dipole resonator leading to a strong resonant electric response when illuminated by electromagnetic fields.1 Starting from an equivalent electrical circuit, we analytically design the parameters of the system to tune the resonance frequency of the harvester at the desired frequency band. Subsequently, we compare these results with numerical simulations, which have been obtained using finite elements numerical simulations. Finally, we optimize the design by investigating the best arrangement for energy harvesting by coupling in parallel and in series many single layers of cut-wire metasurfaces. We also discuss the implementation of different geometries and sizes of the cut-wire metasurface for achieving different center frequencies and bandwidths.

  19. Energy harvesting from an autoparametric vibration absorber

    NASA Astrophysics Data System (ADS)

    Yan, Zhimiao; Hajj, Muhammad R.

    2015-11-01

    The combined control and energy harvesting characteristics of an autoparametric vibration absorber consisting of a base structure subjected to the external force and a cantilever beam with a tip mass are investigated. The piezoelectric sheets are attached to the cantilever beam to convert the vibrations of the base structure into electrical energy. The coupled nonlinear representative model is developed by using the extended Hamiton’s principle. The effects of the electrical load resistance on the frequency and damping ratio of the cantilever beam are analyzed. The impacts of the external force and load resistance on the structural displacements of the base structure and the beam and on the level of harvested energy are determined. The results show that the initial conditions have a significant impact on the system’s response. The relatively high level of energy harvesting is not necessarily accompanied with the minimum displacements of the base structure.

  20. Piezoelectric energy harvesting from raised crosswalk devices

    NASA Astrophysics Data System (ADS)

    Ticali, Dario; Denaro, Mario; Barracco, Alessandro; Guerrieri, Marco

    2015-03-01

    This paper presents the main characteristics of an experimental energy harvesting device that can be used to recover energy from the vehicular and pedestrian traffic. The use of a piezoelectric bender devices leads to a innovative approach to Henergy Harvesting. The study focuses on the definition and specification of a mechanical configuration able to transfer the vibration from the main box to the piezoelectric transducer. The piezoelectric devices tested is the commonly used monolithic piezoceramic material lead-zirconate-titanate (PZT). The experimental results estimate the efficiency of this device tested and identify the feasibility of their use in real world applications. The results presented in this paper show the potential of piezoelectric materials for use in power harvesting applications.

  1. Piezoelectric monolayers as nonlinear energy harvesters.

    PubMed

    López-Suárez, Miquel; Pruneda, Miguel; Abadal, Gabriel; Rurali, Riccardo

    2014-05-01

    We study the dynamics of h-BN monolayers by first performing ab-initio calculations of the deformation potential energy and then solving numerically a Langevine-type equation to explore their use in nonlinear vibration energy harvesting devices. An applied compressive strain is used to drive the system into a nonlinear bistable regime, where quasi-harmonic vibrations are combined with low-frequency swings between the minima of a double-well potential. Due to its intrinsic piezoelectric response, the nonlinear mechanical harvester naturally provides an electrical power that is readily available or can be stored by simply contacting the monolayer at its ends. Engineering the induced nonlinearity, a 20 nm2 device is predicted to harvest an electrical power of up to 0.18 pW for a noisy vibration of 5 pN. PMID:24722065

  2. The effects of harvest regulations on behaviors of duck hunters

    USGS Publications Warehouse

    Haugen, Matthew T.; Powell, Larkin A.; Vrtiska, Mark P.; Pope, Kevin L.

    2015-01-01

    Uncertainty exists as to how duck harvest regulations influence waterfowl hunter behavior. We used the U.S. Fish and Wildlife Service’s Parts Collection Survey to examine how harvest regulations affected behaviors of Central Flyway duck hunters. We stratified hunters into ranked groups based on seasonal harvest and identified three periods (1975–1984, 1988–1993, 2002–2011) that represented different harvest regulations (moderate, restrictive, and liberal, respectively; season length and daily bag limits smallest in restrictive seasons and largest in liberal seasons). We examined variability of seven measures of duck hunter behaviors across the periods: days harvesting ducks, daily harvest, hunter mobility, mallard (Anas platyrhynchos) selectivity, gender selectivity, daily female mallard harvest, and timing of harvest. Hunters reported harvesting ducks on more days, at a higher efficiency, and in slightly more counties during liberal seasons relative to restrictive and moderate seasons. We provide evidence to suggest that future regulation change will affect hunter behaviors.

  3. Managing harvest and habitat as integrated components

    USGS Publications Warehouse

    Osnas, Erik; Runge, Michael C.; Mattsson, Brady J.; Austin, Jane E.; Boomer, G. S.; Clark, R. G.; Devers, P.; Eadie, J. M.; Lonsdorf, E. V.; Tavernia, Brian

    2014-01-01

    In 2007, several important initiatives in the North American waterfowl management community called for an integrated approach to habitat and harvest management. The essence of the call for integration is that harvest and habitat management affect the same resources, yet exist as separate endeavours with very different regulatory contexts. A common modelling framework could help these management streams to better understand their mutual effects. Particularly, how does successful habitat management increase harvest potential? Also, how do regional habitat programmes and large-scale harvest strategies affect continental population sizes (a metric used to express habitat goals)? In the ensuing five years, several projects took on different aspects of these challenges. While all of these projects are still on-going, and are not yet sufficiently developed to produce guidance for management decisions, they have been influential in expanding the dialogue and producing some important emerging lessons. The first lesson has been that one of the more difficult aspects of integration is not the integration across decision contexts, but the integration across spatial and temporal scales. Habitat management occurs at local and regional scales. Harvest management decisions are made at a continental scale. How do these actions, taken at different scales, combine to influence waterfowl population dynamics at all scales? The second lesson has been that consideration of the interface of habitat and harvest management can generate important insights into the objectives underlying the decision context. Often the objectives are very complex and trade-off against one another. The third lesson follows from the second – if an understanding of the fundamental objectives is paramount, there is no escaping the need for a better understanding of human dimensions, specifically the desires of hunters and nonhunters and the role they play in conservation. In the end, the compelling question is

  4. Particulate residue separators for harvesting devices

    DOEpatents

    Hoskinson, Reed L.; Kenney, Kevin L.; Wright, Christopher T.; Hess, John R.

    2010-06-29

    A particulate residue separator and a method for separating a particulate residue stream may include a plenum borne by a harvesting device, and have a first, intake end and a second, exhaust end; first and second particulate residue air streams which are formed by the harvesting device and which travel, at least in part, along the plenum and in a direction of the second, exhaust end; and a baffle assembly which is located in partially occluding relation relative to the plenum, and which substantially separates the first and second particulate residue air streams.

  5. Metamaterial electromagnetic energy harvester with high selective harvesting for left- and right-handed circularly polarized waves

    NASA Astrophysics Data System (ADS)

    Shang, Shuai; Yang, Shizhong; Liu, Jing; Shan, Meng; Cao, Hailin

    2016-07-01

    In this paper, a metamaterial electromagnetic energy harvester constructed via the capacitive loading of metal circular split rings is presented. Each energy-harvesting cell is loaded with a resistance that imitates the input impedance of a rectifier circuit. Specifically, the metamaterial energy harvester has high selective harvesting for left- and right-handed circularly polarized waves. Here, the energy absorption is mostly induced by the resistive load; thus, effective energy harvesting can be achieved. Moreover, the proposed energy harvester exhibits a high-efficiency harvesting for right-handed circularly polarized waves over a wide range of incident angles. Further, a transmission line model is adopted to interpret the energy harvesting mechanism, which shows that a good impedance matching and low dielectric loss can further enhance the harvesting efficiency. To demonstrate the design, a 15 × 15 unit-cell prototype is fabricated and measured, and the measured results reasonably agree with the simulated ones.

  6. Assessment of bias in US waterfowl harvest estimates

    USGS Publications Warehouse

    Padding, Paul I.; Royle, J. Andrew

    2012-01-01

    Context. North American waterfowl managers have long suspected that waterfowl harvest estimates derived from national harvest surveys in the USA are biased high. Survey bias can be evaluated by comparing survey results with like estimates from independent sources. Aims. We used band-recovery data to assess the magnitude of apparent bias in duck and goose harvest estimates, using mallards (Anas platyrhynchos) and Canada geese (Branta canadensis) as representatives of ducks and geese, respectively. Methods. We compared the number of reported mallard and Canada goose band recoveries, adjusted for band reporting rates, with the estimated harvests of banded mallards and Canada geese from the national harvest surveys. Weused the results of those comparisons to develop correction factors that can be applied to annual duck and goose harvest estimates of the national harvest survey. Key results. National harvest survey estimates of banded mallards harvested annually averaged 1.37 times greater than those calculated from band-recovery data, whereas Canada goose harvest estimates averaged 1.50 or 1.63 times greater than comparable band-recovery estimates, depending on the harvest survey methodology used. Conclusions. Duck harvest estimates produced by the national harvest survey from 1971 to 2010 should be reduced by a factor of 0.73 (95% CI = 0.71–0.75) to correct for apparent bias. Survey-specific correction factors of 0.67 (95% CI = 0.65–0.69) and 0.61 (95% CI = 0.59–0.64) should be applied to the goose harvest estimates for 1971–2001 (duck stamp-based survey) and 1999–2010 (HIP-based survey), respectively. Implications. Although this apparent bias likely has not influenced waterfowl harvest management policy in the USA, it does have negative impacts on some applications of harvest estimates, such as indirect estimation of population size. For those types of analyses, we recommend applying the appropriate correction factor to harvest estimates.

  7. Two degrees of freedom piezoelectric vibration energy harvester

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Liu, Shengsheng; Cao, Junyi; Zhou, Shengxi; Lin, Jing

    2016-04-01

    Recently, vibration energy harvesting from surrounding environments to power wearable devices and wireless sensors in structure health monitoring has received considerable interest. Piezoelectric conversion mechanism has been employed to develop many successful energy harvesting devices due to its simple structure, long life span, high harvesting efficiency and so on. However, there are many difficulties of microscale cantilever configurations in energy harvesting from low frequency ambient. In order to improve the adaptability of energy harvesting from ambient vibrations, a two degrees of freedom (2-DOF) magnetic-coupled piezoelectric energy harvester is proposed in this paper. The electromechanical governing models of the cantilever and clamped hybrid energy harvester are derived to describe the dynamic characteristics for 2-DOF magnetic-coupled piezoelectric vibration energy harvester. Numerical simulations based on Matlab and ANSYS software show that the proposed magnetically coupled energy harvester can enhance the effective operating frequency bandwidth and increase the energy density. The experimental voltage responses of 2-DOF harvester under different structure parameters are acquired to demonstrate the effectiveness of the lumped parameter model for low frequency excitations. Moreover, the proposed energy harvester can enhance the energy harvesting performance over a wider bandwidth of low frequencies and has a great potential for broadband vibration energy harvesting.

  8. 50 CFR 622.75 - Harvest limitations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... aquaculture site— (A) May not be placed over naturally occurring reef outcrops, limestone ledges, coral reefs... ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF OF MEXICO, AND SOUTH ATLANTIC Coral and Coral Reefs of the Gulf of Mexico § 622.75 Harvest limitations. (a) Aquacultured live rock. In the...

  9. 50 CFR 622.75 - Harvest limitations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... aquaculture site— (A) May not be placed over naturally occurring reef outcrops, limestone ledges, coral reefs... ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF OF MEXICO, AND SOUTH ATLANTIC Coral and Coral Reefs of the Gulf of Mexico § 622.75 Harvest limitations. (a) Aquacultured live rock. In the...

  10. 50 CFR 622.225 - Harvest limitations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... over naturally occurring reef outcrops, limestone ledges, coral reefs, or vegetated areas. (B) Must be... ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF OF MEXICO, AND SOUTH ATLANTIC Coral, Coral Reefs, and Live/Hard Bottom Habitats of the South Atlantic Region § 622.225 Harvest...

  11. 50 CFR 622.225 - Harvest limitations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... over naturally occurring reef outcrops, limestone ledges, coral reefs, or vegetated areas. (B) Must be... ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF OF MEXICO, AND SOUTH ATLANTIC Coral, Coral Reefs, and Live/Hard Bottom Habitats of the South Atlantic Region § 622.225 Harvest...

  12. Cyclic energy harvesting from pyroelectric materials.

    PubMed

    Mane, Poorna; Xie, Jingsi; Leang, Kam K; Mossi, Karla

    2011-01-01

    A method of continuously harvesting energy from pyroelectric materials is demonstrated using an innovative cyclic heating scheme. In traditional pyroelectric energy harvesting methods, static heating sources are used, and most of the available energy has to be harvested at once. A cyclic heating system is developed such that the temperature varies between hot and cold regions. Although the energy harvested during each period of the heating cycle is small, the accumulated total energy over time may exceed traditional methods. Three materials are studied: a commonly available soft lead zirconate titanate (PZT), a pre-stressed PZT composite, and single-crystal PMN-30PT. Radiation heating and natural cooling are used such that, at smaller cyclic frequencies, the temporal rate of change in temperature is large enough to produce high power densities. The maximum power density of 8.64 μW/cm3 is generated with a PMN-30PT single crystal at an angular velocity of 0.64 rad/s with a rate of 8.5°C/s. The pre-stressed PZT composite generated a power density of 6.31 μW/cm(3), which is 40% larger than the density of 4.48 μW/cm3 obtained from standard PZT. PMID:21244970

  13. Human Motion Energy Harvesting for AAL Applications

    NASA Astrophysics Data System (ADS)

    Ylli, K.; Hoffmann, D.; Becker, P.; Willmann, A.; Folkmer, B.; Manoli, Y.

    2014-11-01

    Research and development into the topic of ambient assisted living has led to an increasing range of devices that facilitate a person's life. The issue of the power supply of these modern mobile systems however has not been solved satisfactorily yet. In this paper a flat inductive multi-coil harvester for integration into the shoe sole is presented. The device is designed for ambient assisted living (AAL) applications and particularly to power a self-lacing shoe. The harvester exploits the horizontal swing motion of the foot to generate energy. Stacks of opposing magnets move through a number of equally spaced coils to induce a voltage. The requirement of a flat structure which can be integrated into the shoe sole is met by a reduced form factor of the magnet stack. In order to exploit the full width of the shoe sole, supporting structures are used to parallelize the harvester and therefore increase the number of active elements, i.e. magnets and coils. The development and characterization of different harvester variations is presented with the best tested design generating an average power of up to 2.14 mW at a compact device size of 75 × 41.5 × 15 mm3 including housing.

  14. Management of post-harvest residue blanket

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Timely and effective residue management is essential for maximum sugar yields. Several studies were implemented in 2003 and harvested in 2004 in an effort to increase the effectiveness of residue management practices. Six studies were conducted to determine the effect of residue removal timing a...

  15. Attitudes toward Posthumous Harvesting and Reproduction

    ERIC Educational Resources Information Center

    Hans, Jason D.

    2008-01-01

    Attitudes toward posthumous harvesting of reproductive material and beliefs about medical professionals' obligation to assist were examined using a multiple segment factorial vignette survey design with 407 randomly selected respondents from a southern state. Attitudes and beliefs were primarily shaped by the vignette couple's marital status,…

  16. 50 CFR 640.21 - Harvest limitations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., DEPARTMENT OF COMMERCE SPINY LOBSTER FISHERY OF THE GULF OF MEXICO AND SOUTH ATLANTIC Management Measures § 640.21 Harvest limitations. (a) Berried lobsters. A berried (egg-bearing) spiny lobster or slipper lobster in or from the EEZ must be returned immediately to the water unharmed. If found in a trap in...

  17. 50 CFR 640.21 - Harvest limitations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... ADMINISTRATION, DEPARTMENT OF COMMERCE SPINY LOBSTER FISHERY OF THE GULF OF MEXICO AND SOUTH ATLANTIC Management Measures § 640.21 Harvest limitations. (a) Berried lobsters. A berried (egg-bearing) spiny lobster or slipper lobster in or from the EEZ must be returned immediately to the water unharmed. If found in a...

  18. 50 CFR 640.21 - Harvest limitations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... ADMINISTRATION, DEPARTMENT OF COMMERCE SPINY LOBSTER FISHERY OF THE GULF OF MEXICO AND SOUTH ATLANTIC Management Measures § 640.21 Harvest limitations. (a) Berried lobsters. A berried (egg-bearing) spiny lobster in or... berried spiny lobster may not be retained in the trap. A berried spiny lobster in or from the EEZ may...

  19. Calibrating your forage harvester's yield monitor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With some attention to the details, you will have a harvester that should be able to produce yield maps that will allow the same precision management that is expected in cereal crops. Forage yield maps, coupled with site-specific technologies in application of soil amendments, fertilizers, and pesti...

  20. Economics of residue harvest: Regional partnership evaluation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Economic analyses on the viability of corn (Zea mays, L.) stover harvest for bioenergy production have largely been based on simulation modeling. While some studies have utilized field research data, most field-based analyses have included a limited number of sites and a narrow geographic distributi...

  1. The Ripe Harvest: Educating Migrant Children.

    ERIC Educational Resources Information Center

    Cheyney, Arnold B., Ed.

    "The Ripe Harvest" is a compilation of original writings by authors who have worked closely with migrant children in a variety of settings. Designed for educators and lay people who are concerned with teaching migrant children, this volume is divided into three sections. Part I discusses human considerations--the dilatory effects of poor health on…

  2. Harvesting the High-Hanging Fruit

    ERIC Educational Resources Information Center

    Kenton, Jay D.

    2014-01-01

    For many years, higher education institutions have been harvesting the low-hanging fruit when it comes to budget reductions and adjustments. Easier changes have often been made--such as cutting administration, using more adjunct faculty, contracting out inefficient or non effective auxiliary operations and so forth. Until recently such strategies,…

  3. 50 CFR 654.21 - Harvest limitations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., DEPARTMENT OF COMMERCE STONE CRAB FISHERY OF THE GULF OF MEXICO Management Measures § 654.21 Harvest... a straight line from the elbow to the tip of the lower immovable finger. The propodus is the largest section of the claw assembly that has both a movable and immovable finger and is located farthest from...

  4. Piezoelectric energy harvesting from hybrid vibrations

    NASA Astrophysics Data System (ADS)

    Yan, Zhimiao; Abdelkefi, Abdessattar; Hajj, Muhammad R.

    2014-02-01

    The concept of harvesting energy from ambient and galloping vibrations of a bluff body with a triangular cross-section geometry is investigated. A piezoelectric transducer is attached to the transverse degree of freedom of the body in order to convert these vibrations to electrical energy. A coupled nonlinear distributed-parameter model is developed that takes into consideration the galloping force and moment nonlinearities and the base excitation effects. The aerodynamic loads are modeled using the quasi-steady approximation. Linear analysis is performed to determine the effects of the electrical load resistance and wind speed on the global damping and frequency of the harvester as well as on the onset of instability. Then, nonlinear analysis is performed to investigate the impact of the base acceleration, wind speed, and electrical load resistance on the performance of the harvester and the associated nonlinear phenomena that take place. The results show that, depending on the interaction between the base and galloping excitations, and the considered values of the wind speed, base acceleration, and electrical load resistance, different nonlinear phenomena arise while others disappear. Short- and open-circuit configurations for different wind speeds and base accelerations are assessed. The results show that the maximum levels of harvested power are accompanied by a minimum transverse displacement when varying the electrical load resistance.

  5. The after-harvest burning question?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Allowing the sugarcane post-harvest residue blanket to remain on the field often reduces ratoon crop yields in temperate climates such as Louisiana. This article outlines the progress of our residue management research focused on reducing the need for burning in Louisiana sugarcane production. Some ...

  6. Sunflower production, harvesting, drying and storage

    SciTech Connect

    Hofman, V.; Berglund, D.; Hellevang, K.

    1982-01-01

    Sunflower, produced for its edible oil, has recently evolved as an important cash crop for the Dakotas and Minnesota. This oilseed crop has increased from 81,000 hectares in the mid-1960's to over 1,620,000 hectares in 1981. Over 90% of the sunflower crop planted in the United States is of oilseed varieties. Sunflower tends to fit well in small grain cropping rotation. Sunflower is planted after small grains in the spring and harvested in the fall, following small grain harvest. Planting of sunflower is recommended from May 20 to May 31. Soil temperature should be between 4/sup 0/C and 10/sup 0/C for germinaton. Diseases occurring in sunflower can greatly reduce yield and hinder harvest operations. A sunflower crop is normally ready for harvest about 120 days after planting. Combines suitable for treshing small gains can be adapted to harvest sunflower. Sunflower can be dried in conventional crop dryers; bin, batch and continuous flow dryers have been used successfully. Sunflower dries easily due to the relatively small amount of water removed. Drying temperatures up to 104/sup 0/C do not have an adverse affect on the oil percentage or fatty acid composition of oil type sunflower. A serious fire hazard exists when drying sunflower. The storage of sunflower is similar to any other crop. The recommended storage moisture content is 8% for oil seeds and 10% for confectionary. Cooling the sunflower seed greatly increases the storability and decreases insect damage. Sunflower should be cooled to about 0/sup 0/C which nearly stops microbial activity. The sunflower should be checked at least weekly. 9 figures, 1 table. (DP)

  7. Big bluestem and switchgrass feedstock harvest timing: Nitrous oxide response to feedstock harvest timing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Switchgrass (Panicum virgatum L.) and big bluestem (Andropogon gerdardii Vitman) are potential bioenergy feedstocks. Feedstock storage limitations, labor constraints for harvest, and environmental benefits provided by perennials are rationales for developing localized perennial feedstock as an alter...

  8. Life Cycle Assessment of Domestic and Agricultural Rainwater Harvesting Systems

    EPA Science Inventory

    To further understanding of the environmental implications of rainwater harvesting and its water savings potential relative to conventional U.S. water delivery infrastructure, we present a method to perform life cycle assessment of domestic rainwater harvesting (DRWH) and agricul...

  9. Energy Harvesting From Low Frequency Applications Using Piezoelectric Materials

    SciTech Connect

    Li, Huidong; Tian, Chuan; Deng, Zhiqun

    2014-11-06

    This paper reviewed the state of research on piezoelectric energy harvesters. Various types of harvester configurations, piezoelectric materials, and techniques used to improve the mechanical-to-electrical energy conversion efficiency were discussed. Most of the piezoelectric energy harvesters studied today have focused on scavenging mechanical energy from vibration sources due to their abundance in both natural and industrial environments. Cantilever beams have been the most studied structure for piezoelectric energy harvester to date because of the high responsiveness to small vibrations.

  10. A spiral-shaped harvester with an improved harvesting element and an adaptive storage circuit.

    PubMed

    Hu, Hongping; Xue, Huan; Hu, Yuantai

    2007-06-01

    A piezoelectric energy harvester consists of a spiral-shaped piezoelectric bimorph to transfer mechanical energy into electric energy, an electrochemical battery to store the scavenged electric energy, and a rectifier together with a step-down dc-dc converter to connect the two components as an integrated system. A spiral-shaped harvesting structure is studied in this paper because it is very useful in the microminiaturization of advanced sensing technology. The aim of employing a step-down dc-dc converter in the storage circuit is to match the optimal output voltage of the piezoelectric bimorph with the battery voltage for efficient charging. In order to raise the output power density of a harvesting element, moreover, we apply a synchronized switch harvesting on inductor (SSHI) in parallel with the piezoelectric bimorph to artificially extend the closed-circuit interval of the rectifier. Numerical results show that the introduction of a dc-dc converter in the storage circuit or a SSHI in the harvesting structure can raise the charging efficiency several times higher than a harvester without a dc-dc converter or an SSHI. PMID:17571816

  11. Critical evaluation and modeling of algal harvesting using dissolved air flotation. DAF Algal Harvesting Modeling

    DOE PAGESBeta

    Zhang, Xuezhi; Hewson, John C.; Amendola, Pasquale; Reynoso, Monica; Sommerfeld, Milton; Chen, Yongsheng; Hu, Qiang

    2014-07-14

    In our study, Chlorella zofingiensis harvesting by dissolved air flotation (DAF) was critically evaluated with regard to algal concentration, culture conditions, type and dosage of coagulants, and recycle ratio. Harvesting efficiency increased with coagulant dosage and leveled off at 81%, 86%, 91%, and 87% when chitosan, Al3+, Fe3+, and cetyl trimethylammonium bromide (CTAB) were used at dosages of 70, 180, 250, and 500 mg g-1, respectively. The DAF efficiency-coagulant dosage relationship changed with algal culture conditions. In evaluating the influence of the initial algal concentration and recycle ratio revealed that, under conditions typical for algal harvesting, we found that itmore » is possible that the number of bubbles is insufficient. A DAF algal harvesting model was developed to explain this observation by introducing mass-based floc size distributions and a bubble limitation into the white water blanket model. Moreover, the model revealed the importance of coagulation to increase floc-bubble collision and attachment, and the preferential interaction of bubbles with larger flocs, which limited the availability of bubbles to the smaller sized flocs. The harvesting efficiencies predicted by the model agree reasonably with experimental data obtained at different Al3+ dosages, algal concentrations, and recycle ratios. Based on this modeling, critical parameters for efficient algal harvesting were identified.« less

  12. Critical evaluation and modeling of algal harvesting using dissolved air flotation. DAF Algal Harvesting Modeling

    SciTech Connect

    Zhang, Xuezhi; Hewson, John C.; Amendola, Pasquale; Reynoso, Monica; Sommerfeld, Milton; Chen, Yongsheng; Hu, Qiang

    2014-07-14

    In our study, Chlorella zofingiensis harvesting by dissolved air flotation (DAF) was critically evaluated with regard to algal concentration, culture conditions, type and dosage of coagulants, and recycle ratio. Harvesting efficiency increased with coagulant dosage and leveled off at 81%, 86%, 91%, and 87% when chitosan, Al3+, Fe3+, and cetyl trimethylammonium bromide (CTAB) were used at dosages of 70, 180, 250, and 500 mg g-1, respectively. The DAF efficiency-coagulant dosage relationship changed with algal culture conditions. In evaluating the influence of the initial algal concentration and recycle ratio revealed that, under conditions typical for algal harvesting, we found that it is possible that the number of bubbles is insufficient. A DAF algal harvesting model was developed to explain this observation by introducing mass-based floc size distributions and a bubble limitation into the white water blanket model. Moreover, the model revealed the importance of coagulation to increase floc-bubble collision and attachment, and the preferential interaction of bubbles with larger flocs, which limited the availability of bubbles to the smaller sized flocs. The harvesting efficiencies predicted by the model agree reasonably with experimental data obtained at different Al3+ dosages, algal concentrations, and recycle ratios. Based on this modeling, critical parameters for efficient algal harvesting were identified.

  13. Increasing global crop harvest frequency: recent trends and future directions

    NASA Astrophysics Data System (ADS)

    Ray, Deepak K.; Foley, Jonathan A.

    2013-12-01

    The world’s agricultural systems face the challenge of meeting the rising demands from population growth, changing dietary preferences, and expanding biofuel use. Previous studies have put forward strategies for meeting this growing demand by increasing global crop production, either expanding the area under cultivation or intensifying the crop yields of our existing agricultural lands. However, another possible means for increasing global crop production has received less attention: increasing the frequency of global cropland harvested each year. Historically, many of the world’s croplands were left fallow, or had failed harvests, each year, foregoing opportunities for delivering crop production. Furthermore, many regions, particularly in the tropics, may be capable of multiple harvests per year, often more than are harvested today. Here we analyze a global compilation of agricultural statistics to show how the world’s harvested cropland has changed. Between 2000 and 2011, harvested land area grew roughly 4 times faster than total standing cropland area. Using a metric of cropland harvest frequency (CHF)—the ratio of land harvested each year to the total standing cropland—and its recent trends, we identify countries that harvest their croplands more frequently, and those that have the potential to increase their cropland harvest frequency. We suggest that a possible ‘harvest gap’ may exist in many countries that represents an opportunity to increase crop production on existing agricultural lands. However, increasing the harvest frequency of existing croplands could have significant environmental and social impacts, which need careful evaluation.

  14. 50 CFR 20.20 - Migratory Bird Harvest Information Program.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 8 2011-10-01 2011-10-01 false Migratory Bird Harvest Information Program... IMPORTATION OF WILDLIFE AND PLANTS (CONTINUED) MIGRATORY BIRD HUNTING Taking § 20.20 Migratory Bird Harvest... information will be used to provide a sampling frame for the national Migratory Bird Harvest Survey....

  15. 50 CFR 20.20 - Migratory Bird Harvest Information Program.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 6 2010-10-01 2010-10-01 false Migratory Bird Harvest Information Program... IMPORTATION OF WILDLIFE AND PLANTS (CONTINUED) MIGRATORY BIRD HUNTING Taking § 20.20 Migratory Bird Harvest... information will be used to provide a sampling frame for the national Migratory Bird Harvest Survey....

  16. 50 CFR 680.21 - Crab harvesting cooperatives.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Crab harvesting cooperatives. 680.21... ZONE OFF ALASKA Management Measures § 680.21 Crab harvesting cooperatives. This section governs the formation and operation of crab harvesting cooperatives. The regulations in this section apply only to...

  17. 50 CFR 680.21 - Crab harvesting cooperatives.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Crab harvesting cooperatives. 680.21... ZONE OFF ALASKA Management Measures § 680.21 Crab harvesting cooperatives. This section governs the formation and operation of crab harvesting cooperatives. The regulations in this section apply only to...

  18. 50 CFR 680.21 - Crab harvesting cooperatives.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Crab harvesting cooperatives. 680.21... ZONE OFF ALASKA Management Measures § 680.21 Crab harvesting cooperatives. This section governs the formation and operation of crab harvesting cooperatives. The regulations in this section apply only to...

  19. 50 CFR 680.21 - Crab harvesting cooperatives.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Crab harvesting cooperatives. 680.21... ZONE OFF ALASKA Management Measures § 680.21 Crab harvesting cooperatives. This section governs the formation and operation of crab harvesting cooperatives. The regulations in this section apply only to...

  20. 50 CFR 680.21 - Crab harvesting cooperatives.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Crab harvesting cooperatives. 680.21... ZONE OFF ALASKA Management Measures § 680.21 Crab harvesting cooperatives. This section governs the formation and operation of crab harvesting cooperatives. The regulations in this section apply only to...

  1. 50 CFR 20.20 - Migratory Bird Harvest Information Program.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 9 2013-10-01 2013-10-01 false Migratory Bird Harvest Information Program... IMPORTATION OF WILDLIFE AND PLANTS (CONTINUED) MIGRATORY BIRD HUNTING Taking § 20.20 Migratory Bird Harvest... information will be used to provide a sampling frame for the national Migratory Bird Harvest Survey....

  2. 50 CFR 20.20 - Migratory Bird Harvest Information Program.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 9 2012-10-01 2012-10-01 false Migratory Bird Harvest Information Program... IMPORTATION OF WILDLIFE AND PLANTS (CONTINUED) MIGRATORY BIRD HUNTING Taking § 20.20 Migratory Bird Harvest... information will be used to provide a sampling frame for the national Migratory Bird Harvest Survey....

  3. 50 CFR 660.321 - Black rockfish harvest guideline.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Black rockfish harvest guideline. 660.321 Section 660.321 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND... Groundfish Fisheries § 660.321 Black rockfish harvest guideline. From the commercial harvest of...

  4. Evolutionary consequences of nonselective harvesting in density-dependent populations.

    PubMed

    Engen, Steinar; Lande, Russell; Sæther, Bernt-Erik

    2014-12-01

    There is now considerable empirical evidence that evolutionary changes in many phenotypic characters, such as body mass, age at maturation, and timing of breeding, often occur in populations subject to intense harvesting over longer periods. Here, we analyze the evolutionary component of the selection due to nonselective harvesting, which will operate even under selective harvesting and may generate a large evolutionary response. If phenotype affects susceptibility to density dependence-for example, through resource limitation-then nonselective harvesting can induce evolutionary change through its effect on population density. We provide a model for evolution of a quantitative character in such a fluctuating density-dependent population, using the diffusion approximation to describe jointly the temporal changes in mean phenotype and log population size. We show how nonselective harvesting in particular generates r-selection governed by genetic variation in the strength of density regulation and the magnitude of population fluctuations. We show that r-selection caused by nonselective harvesting is proportional to the mean fraction of the population harvested. We then compare the short-term as well as the long-term evolutionary impact of nonselective harvesting for different harvesting strategies by using the mean harvest fraction for different strategies. This comparison is performed for three different harvesting strategies: constant, proportional, and threshold harvesting. The more ecologically sustainable strategies also produce smaller evolutionary changes. PMID:25438172

  5. A New Grain Harvesting System for Single Pass Grain Harvest, Biomass Collection, Crop Residue Sizing and Grain Segregation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A cereal grain harvesting system is introduced that combines existing technologies in a unique way to improve cereal grain harvest performance, profitability and efficiently collect biomass. The harvesting system is comprised of three machines – one to gather the crop and prepare the residue for no...

  6. A New Grain Harvesting System for Single-Pass Grain Harvest, Biomass Collection, Crop Residue Sizing, and Grain Segregation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A cereal grain harvesting system is introduced that combines existing technologies in a unique way to improve cereal grain harvest performance, profitability and efficiently collect biomass. The harvesting system is comprised of three machines – one to gather the crop and prepare the residue for no...

  7. Piezoelectric diaphragm for vibration energy harvesting.

    PubMed

    Minazara, E; Vasic, D; Costa, F; Poulin, G

    2006-12-22

    This paper presents a technique of electric energy generation using a mechanically excited unimorph piezoelectric membrane transducer. The electrical characteristics of the piezoelectric power generator are investigated under dynamic conditions. The electromechanical model of the generator is presented and used to predict its electrical performances. The experiments was performed with a piezoelectric actuator (shaker) moving a macroscopic 25 mm diameter piezoelectric membrane. A power of 0.65 mW was generated at the resonance frequency (1.71 kHz) across a 5.6 kOmega optimal resistor and for a 80 N force. A special electronic circuit has been conceived in order to increase the power harvested by the piezoelectric transducer. This electrical converter applies the SSHI (synchronized switch harvesting on inductor) technique, and leads to remarkable results: under the same actuation conditions the generated power reaches 1.7 mW, which is sufficient to supply a large range of low consumption sensors. PMID:16814837

  8. Energy harvesting in high voltage measuring techniques

    NASA Astrophysics Data System (ADS)

    Żyłka, Pawel; Doliński, Marcin

    2016-02-01

    The paper discusses selected problems related to application of energy harvesting (that is, generating electricity from surplus energy present in the environment) to supply autonomous ultra-low-power measurement systems applicable in high voltage engineering. As a practical example of such implementation a laboratory model of a remote temperature sensor is presented, which is self-powered by heat generated in a current-carrying busbar in HV- switchgear. Presented system exploits a thermoelectric harvester based on a passively cooled Peltier module supplying micro-power low-voltage dc-dc converter driving energy-efficient temperature sensor, microcontroller and a fibre-optic transmitter. Performance of the model in laboratory simulated conditions are presented and discussed.

  9. The Interfamilial Principle and the Harvest Festival.

    PubMed

    Cherkassky, Lisa

    2016-03-01

    It is widely accepted that younger children can act as saviour siblings by donating cord blood or bone marrow to their gravely-ill brothers or sisters. However, it is under dispute whether these procedures are in the best interests of the child. This article suggests that parents may be relying on a thinly-veiled interfamilial approach, where the wider benefit to the whole family is used to justify the procedure to the Human Tissue Authority in the United Kingdom. This article suggests that the merging of familial interests to validate a non-therapeutic bone marrow harvest on a child forces altruism in a patient too young to understand, rendering the harvests unlawful under current law. PMID:27044172

  10. Tree-inspired piezoelectric energy harvesting

    NASA Astrophysics Data System (ADS)

    Hobbs, William B.; Hu, David L.

    2012-01-01

    We design and test micro-watt energy-harvesters inspired by tree trunks swaying in the wind. A uniform flow vibrates a linear array of four cylinders affixed to piezoelectric energy transducers. Particular attention is paid to measuring the energy generated as a function of cylinder spacing, flow speed, and relative position of the cylinder within the array. Peak power is generated using cylinder center-to-center spacings of 3.3 diameters and flow speeds in which the vortex shedding frequency is 1.6 times the natural frequency of the cylinders. Using these flow speeds and spacings, the power generated by downstream cylinders can exceed that of leading cylinders by more than an order of magnitude. We visualize the flow in this system by studying the behavior of a dynamically matched flowing soap film with imbedded styrofoam disks. Our qualitative visualizations suggest that peak energy harvesting occurs under conditions in which vortices have fully detached from the leading cylinder.

  11. Vibration energy harvesting with polyphase AC transducers

    NASA Astrophysics Data System (ADS)

    McCullagh, James J.; Scruggs, Jeffrey T.; Asai, Takehiko

    2016-04-01

    Three-phase transduction affords certain advantages in the efficient electromechanical conversion of energy, especially at higher power scales. This paper considers the use of a three-phase electric machine for harvesting energy from vibrations. We consider the use of vector control techniques, which are common in the area of industrial electronics, for optimizing the feedback loops in a stochastically-excited energy harvesting system. To do this, we decompose the problem into two separate feedback loops for direct and quadrature current components, and illustrate how each might be separately optimized to maximize power output. In a simple analytical example, we illustrate how these techniques might be used to gain insight into the tradeoffs in the design of the electronic hardware and the choice of bus voltage.

  12. Opportunities for energy harvesting in automobile factories

    NASA Astrophysics Data System (ADS)

    Adegoke, E. I.; Edwards, R. M.; Whittow, Will; Bindel, Axel; Peca, Marco

    2016-04-01

    This paper investigates the opportunities of deploying distributed sensors within the manufacturing environment of a large scale automobile plant using energy harvesting techniques. Measurements were taken in three domains at the plant in order to characterize ambient energy. Due to the location of the plant, the RF power density for radio access technologies present varied between -127 dBm/cm2 and -113 dBm/cm2. The maximum temperature difference measured within accessible distance from machine parts on the production lines surveyed was 10°C. Indoor lighting was dominant at the plant via fluorescent tubes, with average irradiance of 1 W/m2. The results obtained from this measurement campaign showed that indoor lighting was the most suitable ambient source for energy harvesting.

  13. On thermoelectric and pyroelectric energy harvesting

    NASA Astrophysics Data System (ADS)

    Sebald, Gael; Guyomar, Daniel; Agbossou, Amen

    2009-12-01

    This paper deals with small-power energy harvesting from heat. It can be achieved using both thermoelectric and pyroelectric effects. In the first case, temperature gradients are necessary. The main difficulty of thermoelectric energy harvesting is imposing a large temperature gradient. This requires huge heat flows because of the limited surface heat exchanges and the large heat conductivity of thermoelectric materials. This results in a drastic decrease of power and the efficiency of conversion. In case of pyroelectric energy harvesting, a time varying temperature is necessary. Although such a temperature time profile is hard to find, the overall optimization is easier than the thermoelectric strategy. Indeed, it depends much less on heat exchange between the sample and the outer medium, than on heat capacity that dimensions optimization may easily compensate. As a consequence, it is shown that the efficiency and output power may be much larger using pyroelectric energy harvesting than thermoelectric methods. For instance, using a limited temperature gradient due to the limited heat exchange, a maximum efficiency of 1.7% of Carnot efficiency can be expected using a thermoelectric module. On the contrary, a pyroelectric device may reach an efficiency up to 50% of Carnot efficiency. Finally, an illustration shows an estimation of the output power that could be expected from natural time variations of temperature of a wearable device. Power peaks up to 0.2 mW cm-3 were found and a mean power of 1 µW cm-3 on average was determined within 24 h testing.

  14. Recent Advancements in Nanogenerators for Energy Harvesting.

    PubMed

    Hu, Fei; Cai, Qian; Liao, Fan; Shao, Mingwang; Lee, Shuit-Tong

    2015-11-11

    Nanomaterial-based generators are a highly promising power supply for micro/nanoscale devices, capable of directly harvesting energy from ambient sources without the need for batteries. These generators have been designed within four main types: piezoelectric, triboelectric, thermoelectric, and electret effects, and consist of ZnO-based, silicon-based, ferroelectric-material-based, polymer-based, and graphene-based examples. The representative achievements, current challenges, and future prospects of these nanogenerators are discussed. PMID:26378993

  15. Bioinspired Breathable Architecture for Water Harvesting

    PubMed Central

    von Spreckelsen, Rowan M.; Harris, Matthew T.; Wigzell, James M.; Fraser, Rebekah C.; Carletto, Andrea; Mosquin, Daniel P. K.; Justice, Douglas; Badyal, Jas Pal S.

    2015-01-01

    Thuja plicata is a coniferous tree which displays remarkable water channelling properties. In this article, an easily fabricated mesh inspired by the hierarchical macro surface structure of Thuja plicata branchlets is described which emulates this efficient water collection behaviour. The key parameters are shown to be the pore size, pore angle, mesh rotation, tilt angle (branch droop) and layering (branch overlap). Envisaged societal applications include water harvesting and low cost breathable architecture for developing countries. PMID:26577768

  16. Fat embolism syndrome following bone marrow harvesting.

    PubMed

    Baselga, J; Reich, L; Doherty, M; Gulati, S

    1991-06-01

    A case of fat embolism syndrome is reported following an uncomplicated bone marrow harvest. The presenting symptoms were restlessness, shortness of breath and arterial hypoxemia. A lung perfusion scan ruled out the presence of a lung thromboembolism. The patient received supportive therapy and recovered within a few hours. We speculate that the larger gauge needle (13 vs 15) used to aspirate the bone marrow may have represented increased trauma to the iliac crest leading to fat embolism. PMID:1873595

  17. Broadband electrostatic device for power harvesting

    NASA Astrophysics Data System (ADS)

    Yuksek, N. S.; Feng, Z. C.; Almasri, M.

    2015-12-01

    This paper introduces a prototype energy harvester device with integrated MEMS capacitive plate and two impact oscillators for transferring energy from low frequency structural vibration with varying mechanical spectra to a vibration of a high resonance frequency cantilever. The use of the two impact oscillators not only harvested energy at low frequencies but also had demonstrated exceptionally sufficient and optimum dynamic responses to a broad frequency bandwidth between 13 Hz and 39 Hz, the bandwidth covering wide range of residual vibrations in structures and systems, without reduction in output power. The device was designed with a MEMS capacitor fixed at the free end of an aluminium cantilever clamped at one side, with a high resonance frequency of 605 Hz matched with the single-cavity capacitor, and two cantilevers made of Al sheet with low resonance frequencies of 18 Hz and 25 Hz. The results clearly demonstrates the device's ability for frequency up- conversion and harvesting power on a wide range from 13 Hz to 39 Hz at 1g excitation.

  18. Harvesting the biosphere: the human impact.

    PubMed

    Smil, Vaclav

    2011-01-01

    The human species has evolved to dominate the biosphere: global anthropomass is now an order of magnitude greater than the mass of all wild terrestrial mammals. As a result, our dependence on harvesting the products of photosynthesis for food, animal feed, raw materials, and energy has grown to make substantial global impacts. During the past two millennia these harvests, and changes of land use due to deforestation and conversions of grasslands and wetlands, have reduced the stock of global terrestrial plant mass by as much as 45 percent, with the twentieth-century reduction amounting to more than 15 percent. Current annual harvests of phytomass have been a significant share of the global net primary productivity (NPP, the total amount of new plant tissues created by photosynthesis). Some studies put the human appropriation of NPP (the ratio of these two variables) as high as 40 percent but the measure itself is problematic. Future population growth and improved quality of life will result in additional claims on the biosphere, but options to accommodate these demands exist without severely compromising the irreplaceable biospheric services. PMID:22319767

  19. Microalgae harvesting and subsequent biodiesel conversion.

    PubMed

    Tran, Dang-Thuan; Le, Bich-Hanh; Lee, Duu-Jong; Chen, Ching-Lung; Wang, Hsiang-Yu; Chang, Jo-Shu

    2013-07-01

    Chlorella vulgaris ESP-31 containing 22.7% lipid was harvested by coagulation (using chitosan and polyaluminium chloride (PACl) as the coagulants) and centrifugation. The harvested ESP-31 was directly employed as the oil source for biodiesel production via transesterification catalyzed by immobilized Burkholderia lipase and by a synthesized solid catalyst (SrO/SiO2). Both enzymatic and chemical transesterification were significantly inhibited in the presence of PACl, while the immobilized lipase worked well with wet chitosan-coagulated ESP-31, giving a high biodiesel conversion of 97.6% w/w oil, which is at a level comparable to that of biodiesel conversion from centrifugation-harvested microalgae (97.1% w/w oil). The immobilized lipase can be repeatedly used for three cycles without significant loss of its activity. The solid catalyst SrO/SiO2 worked well with water-removed centrifuged ESP-31 with a biodiesel conversion of 80% w/w oil, but the conversion became lower (55.7-61.4% w/w oil) when using water-removed chitosan-coagulated ESP-31 as the oil source. PMID:23688670

  20. Energy harvesting with coupled magnetostrictive resonators

    NASA Astrophysics Data System (ADS)

    Naik, Suketu; Phipps, Alex; In, Visarath; Cavaroc, Peyton; Matus-Vargas, Antonio; Palacios, Antonio; Gonzalez-Hernandez, H. G.

    2014-03-01

    We report the investigation of an energy harvesting system composed of coupled resonators with the magnetostrictive material Galfenol (FeGa). A coupled system of meso-scale (1-10 cm) cantilever beams for harvesting vibration energy is described for powering and aiding the performance of low-power wireless sensor nodes. Galfenol is chosen in this work for its durability, compared to the brittleness often encountered with piezoelectric materials, and high magnetomechanical coupling. A lumped model, which captures both the mechanical and electrical behavior of the individual transducers, is first developed. The values of the lumped element parameters are then derived empirically from fabricated beams in order to compare the model to experimental measurements. The governing equations of the coupled system lead to a system of differential equations with all-to-all coupling between transducers. An analysis of the system equations reveals different patterns of collective oscillations. Among the many different patterns, a synchronous state appears to yield the maximum energy that can be harvested by the system. Experiments on coupled system shows that the coupled system exhibits synchronization and an increment in the output power. Discussion of the required power converters is also included.

  1. Energy-harvesting at the Nanoscale

    NASA Astrophysics Data System (ADS)

    Jordan, Andrew; Sothmann, Björn; Sánchez, Rafael; Büttiker, Markus

    2013-03-01

    Energy harvesting is the process by which energy is taken from the environment and transformed to provide power for electronics. Specifically, the conversion of thermal energy into electrical power, or thermoelectrics, can play a crucial role in future developments of alternative sources of energy. Unfortunately, present thermoelectrics have low efficiency. Therefore, an important task in condensed matter physics is to find new ways to harvest ambient thermal energy, particularly at the smallest length scales where electronics operate. To achieve this goal, there is on one hand the miniaturizing of electrical devices, and on the other, the maximization of either efficiency or power the devices produce. We will present the theory of nano heat engines able to efficiently convert heat into electrical power. We propose a resonant tunneling quantum dot engine that can be operated either in the Carnot efficient mode, or maximal power mode. The ability to scale the power by putting many such engines in a ``Swiss cheese sandwich'' geometry gives a paradigmatic system for harvesting thermal energy at the nanoscale. This work was supported by the US NSF Grant No. DMR-0844899, the Swiss NSF, the NCCR MaNEP and QSIT, the European STREP project Nanopower, the CSIC and FSE JAE-Doc program, the Spanish MAT2011-24331 and the ITN Grant 234970 (EU)

  2. Comparison of flocculation methods for harvesting Dunaliella.

    PubMed

    Pirwitz, Kristin; Rihko-Struckmann, Liisa; Sundmacher, Kai

    2015-11-01

    Low cell concentrations of Dunaliella salina in production scale cultivations require high energy input for biomass harvesting. Flocculation is a potential preconcentration method to lower the dewatering costs for the β-carotene production. In the present study, optimal flocculant dosages were determined for several metal salts, NaOH, Ca(OH)2 and Al-electrolysis. Beside harvesting efficiency ηH and concentration factor CF, also the recyclability of the separated medium as well as the influence of the cell physiology on the harvesting performance were analyzed for selected flocculants. To assess the possible recycle of non-sedimented cells for the inoculation of new cultivations, cell vitality and the photosynthetic activity of D. salina were analyzed after the flocculation. As a result, the flocculation with NaOH led to a clear inhibition of both, the algal growth on recycled medium and the algal photosynthetic activity. The addition of FeCl3 seems most promising to flocculate D. salina. PMID:26232773

  3. Energy harvesting in the nonlinear electromagnetic system

    NASA Astrophysics Data System (ADS)

    Kucab, K.; Górski, G.; Mizia, J.

    2015-11-01

    We examine the electrical response of electromagnetic device working both in the linear and nonlinear domain. The harvester is consisted of small magnet moving in isolating tube surrounded by the coil attached to the electrical circuit. In the nonlinear case the magnet vibrates in between two fixed magnets attached to the both ends of the tube. Additionally we use two springs which limit the movement of the small magnet. The linear case is when the moving magnet is attached to the repelling springs, and the static magnets have been replaced by the non-magnetic material. The potentials and forces were calculated using both the analytical expressions and the finite elements method. We compare the results for energy harvesting obtained in these two cases. The generated output power in the linear case reaches the peak value 80 mW near the resonance frequency ω0 for maximum base acceleration considered by us, whereas in the non-linear case the corresponding outpot power has the peak value 95 mW and additionally relatively high values in the excitation frequencies range up to ω = 1.2ω0. The numerical results also show that the power efficiency in the nonlinear case exceeds the corresponding efficiency in the linear case at relatively high values of base accelerations greater than 5 g. The results show the increase of harvested energy in the broad band of excitation frequencies in the nonlinear case.

  4. Light-harvesting in photosystem I.

    PubMed

    Croce, Roberta; van Amerongen, Herbert

    2013-10-01

    This review focuses on the light-harvesting properties of photosystem I (PSI) and its LHCI outer antenna. LHCI consists of different chlorophyll a/b binding proteins called Lhca's, surrounding the core of PSI. In total, the PSI-LHCI complex of higher plants contains 173 chlorophyll molecules, most of which are there to harvest sunlight energy and to transfer the created excitation energy to the reaction center (RC) where it is used for charge separation. The efficiency of the complex is based on the capacity to deliver this energy to the RC as fast as possible, to minimize energy losses. The performance of PSI in this respect is remarkable: on average it takes around 50 ps for the excitation to reach the RC in plants, without being quenched in the meantime. This means that the internal quantum efficiency is close to 100% which makes PSI the most efficient energy converter in nature. In this review, we describe the light-harvesting properties of the complex in relation to protein and pigment organization/composition, and we discuss the important parameters that assure its very high quantum efficiency. Excitation energy transfer and trapping in the core and/or Lhcas, as well as in the supercomplexes PSI-LHCI and PSI-LHCI-LHCII are described in detail with the aim of giving an overview of the functional behavior of these complexes. PMID:23645376

  5. Photosynthetic light harvesting: excitons and coherence

    PubMed Central

    Fassioli, Francesca; Dinshaw, Rayomond; Arpin, Paul C.; Scholes, Gregory D.

    2014-01-01

    Photosynthesis begins with light harvesting, where specialized pigment–protein complexes transform sunlight into electronic excitations delivered to reaction centres to initiate charge separation. There is evidence that quantum coherence between electronic excited states plays a role in energy transfer. In this review, we discuss how quantum coherence manifests in photosynthetic light harvesting and its implications. We begin by examining the concept of an exciton, an excited electronic state delocalized over several spatially separated molecules, which is the most widely available signature of quantum coherence in light harvesting. We then discuss recent results concerning the possibility that quantum coherence between electronically excited states of donors and acceptors may give rise to a quantum coherent evolution of excitations, modifying the traditional incoherent picture of energy transfer. Key to this (partially) coherent energy transfer appears to be the structure of the environment, in particular the participation of non-equilibrium vibrational modes. We discuss the open questions and controversies regarding quantum coherent energy transfer and how these can be addressed using new experimental techniques. PMID:24352671

  6. Flexible piezoelectric energy harvesting from jaw movements

    NASA Astrophysics Data System (ADS)

    Delnavaz, Aidin; Voix, Jérémie

    2014-10-01

    Piezoelectric fiber composites (PFC) represent an interesting subset of smart materials that can function as sensor, actuator and energy converter. Despite their excellent potential for energy harvesting, very few PFC mechanisms have been developed to capture the human body power and convert it into an electric current to power wearable electronic devices. This paper provides a proof of concept for a head-mounted device with a PFC chin strap capable of harvesting energy from jaw movements. An electromechanical model based on the bond graph method is developed to predict the power output of the energy harvesting system. The optimum resistance value of the load and the best stretch ratio in the strap are also determined. A prototype was developed and tested and its performances were compared to the analytical model predictions. The proposed piezoelectric strap mechanism can be added to all types of head-mounted devices to power small-scale electronic devices such as hearing aids, electronic hearing protectors and communication earpieces.

  7. Environmental effects of harvesting forests for energy

    SciTech Connect

    Van Hook, R. I.; Johnson, D. W.; West, D. C.; Mann, L. K.

    1980-01-01

    Present interest in decreasing US dependence on foreign oil by increasing the use of wood for energy may bring about a change in our forest utilization policies. In the past, forests have been removed in areas believed to be suited for agriculture, or sawtimber and pulp have been the only woody material removed in any quantity from land not generally considered tillable. The new demands on wood for energy are effecting a trend toward (1) removing all woody biomass from harvested areas, (2) increasing the frequency of harvesting second growth forests, and (3) increasing production with biomass plantations. Considering the marginal quality of much of the remaining forested land, the impacts of these modes of production could be significant. For example, it is anticipated that increased losses of nutrients and carbon will occur by direct forest removal and through erosion losses accelerated by forest clearing. There are, however, control measures that can be utilized in minimizing both direct and indirect effects of forest harvesting while maximizing woody biomass production.

  8. Optimum harvest maturity for Leymus chinensis seed

    PubMed Central

    Lin, Jixiang; Wang, Yingnan; Qi, Mingming; Li, Xiaoyu; Yang, Chunxue; Wang, Yongcui

    2016-01-01

    ABSTRACT Timely harvest is critical to achieve maximum seed viability and vigour in agricultural production. However, little information exists concerning how to reap the best quality seeds of Leymus chinensis, which is the dominant and most promising grass species in the Songnen Grassland of Northern China. The objective of this study was to investigate and evaluate possible quality indices of the seeds at different days after peak anthesis. Seed quality at different development stages was assessed by the colours of the seed and lemmas, seed weight, moisture content, electrical conductivity of seed leachate and germination indices. Two consecutive years of experimental results showed that the maximum seed quality was recorded at 39 days after peak anthesis. At this date, the colours of the seed and lemmas reached heavy brown and yellow, respectively. The seed weight was highest and the moisture content and the electrical conductivity of seed leachate were lowest. In addition, the seed also reached its maximum germination percentage and energy at this stage, determined using a standard germination test (SGT) and accelerated ageing test (AAT). Thus, Leymus chinensis can be harvested at 39 days after peak anthesis based on the changes in parameters. Colour identification can be used as an additional indicator to provide a more rapid and reliable measure of optimum seed maturity; approximately 10 days after the colour of the lemmas reached yellow and the colour of the seed reached heavy brown, the seed of this species was suitable for harvest. PMID:27170257

  9. Optimum harvest maturity for Leymus chinensis seed.

    PubMed

    Lin, Jixiang; Wang, Yingnan; Qi, Mingming; Li, Xiaoyu; Yang, Chunxue; Wang, Yongcui; Mu, Chunsheng

    2016-01-01

    Timely harvest is critical to achieve maximum seed viability and vigour in agricultural production. However, little information exists concerning how to reap the best quality seeds of Leymus chinensis, which is the dominant and most promising grass species in the Songnen Grassland of Northern China. The objective of this study was to investigate and evaluate possible quality indices of the seeds at different days after peak anthesis. Seed quality at different development stages was assessed by the colours of the seed and lemmas, seed weight, moisture content, electrical conductivity of seed leachate and germination indices. Two consecutive years of experimental results showed that the maximum seed quality was recorded at 39 days after peak anthesis. At this date, the colours of the seed and lemmas reached heavy brown and yellow, respectively. The seed weight was highest and the moisture content and the electrical conductivity of seed leachate were lowest. In addition, the seed also reached its maximum germination percentage and energy at this stage, determined using a standard germination test (SGT) and accelerated ageing test (AAT). Thus, Leymus chinensis can be harvested at 39 days after peak anthesis based on the changes in parameters. Colour identification can be used as an additional indicator to provide a more rapid and reliable measure of optimum seed maturity; approximately 10 days after the colour of the lemmas reached yellow and the colour of the seed reached heavy brown, the seed of this species was suitable for harvest. PMID:27170257

  10. Harvesting under transient conditions: harvested energy as a proxy for optimal resonance frequency detuning

    NASA Astrophysics Data System (ADS)

    Hynds, Taylor D.; Kauffman, Jeffrey L.

    2015-04-01

    Piezoelectric-based vibration energy harvesting is of interest in a wide range of applications, and a number of harvesting schemes have been proposed and studied { primarily when operating under steady state conditions. However, energy harvesting behavior is rarely studied in systems with transient excitations. This paper will work to develop an understanding of this behavior within the context of a particular vibration reduction technique, resonance frequency detuning. Resonance frequency detuning provides a method of reducing mechanical response at structural resonances as the excitation frequency sweeps through a given range. This technique relies on switching the stiffness state of a structure at optimal times to detune its resonance frequency from that of the excitation. This paper examines how this optimal switch may be triggered in terms of the energy harvested, developing a normalized optimal switch energy that is independent of the open- and short-circuit resistances. Here the open- and short-circuit shunt resistances refer to imposed conditions that approximate the open- and short-circuit conditions, via high and low resistance shunts. These conditions are practically necessary to harvest the small amounts of power needed to switch stiffness states, as open-circuit and closed-circuit refer to infinite resistance and zero resistance, respectively, and therefore no energy passes through the harvesting circuit. The limiting stiffness states are then defined by these open- and short-circuit resistances. The optimal switch energy is studied over a range of sweep rates, damping ratios, and coupling coefficients; it is found to increase with the coupling coefficient and decrease as the sweep rate and damping ratio increase, behavior which is intuitive. Higher coupling means more energy is converted by the piezoelectric material, and therefore more energy is harvested in a given time; an increased sweep rate means resonance is reached sooner, and there will less

  11. Analysis of five simulated straw harvest scenarios

    SciTech Connect

    Sokhansanj, Shahabaddine; Turhollow Jr, Anthony F; Stephen, Jamie; Stumborg, Mark; Fenton, James; Mani, Sudhagar

    2008-01-01

    Almost 36 million tonnes (t) of cereal grains are harvested annually on more than 16 million hectares (ha) in Canada. The net straw production varies year by year depending upon weather patterns, crop fertility, soil conservation measures, harvest method, and plant variety. The net yield of straw, after discounting for soil conservation, averages approximately 2.5 dry (d)t ha-1. Efficient equipment is needed to collect and package the material as a feedstock for industrial applications. This paper investigates the costs, energy input, and emissions from power equipment used for harvesting straw. Five scenarios were investigated: (1) large square bales, (2) round bales, (3) large compacted stacks (loafs), (4) dried chops, and (5) wet chops. The baled or loafed biomass is stacked next to the farm. Dry chop is collected in a large pile and wet chop is ensiled. The baling and stacking cost was $21.47 dt-1 (dry tonne), with little difference between round and large square baling. Loafing was the cheapest option at $17.08 dt-1. Dry chop and piling was $23.90 dt-1 and wet chop followed by ensiling was $59.75 dt-1. A significant portion of the wet chop cost was in ensiling. Energy input and emissions were proportional to the costs for each system, except for loafing, which required more energy input than the baling systems. As a fraction of the energy content of biomass (roughly 16 GJ dt-1), the energy input ranged from 1.2% for baling to 3.2% for ensiling. Emissions from the power equipment ranged from 20.3 kg CO2e dt-1 to more than 40 kg CO2e dt-1. A sensitivity analysis on the effect of yield on collection costs showed that a 33% increase in yield reduced the cost by 20%. Similarly a sensitivity analysis on weather conditions showed that a 10oC cooler climate extended the harvest period by 5-10 days whereas a 10oC warmer climate shortened the harvest period by 2-3 days.

  12. Energy harvesting in a quad-stable harvester subjected to random excitation

    NASA Astrophysics Data System (ADS)

    Zhou, Zhi-yong; Qin, Wei-yang; Zhu, Pei

    2016-02-01

    In response to the defects of bi-stable energy harvester (BEH), we develop a novel quad-stable energy harvester (QEH) to improve harvesting efficiency. The device is made up of a bimorph cantilever beam having a tip magnet and three external fixed magnets. By adjusting the positions of the fixed magnets and the distances between the tip magnet and the fixed ones, the quad-stable equilibrium positions can emerge. The potential energy shows that the barriers of the QEH are lower than those of the BEH for the same separation distance. Experiment results reveal that the QEH can realize snap-through easier and make a dense snap-through in response under random excitation. Moreover, its strain and voltage both become large for snap-through between the nonadjacent stable positions. There exists an optimal separation distance for different excitation intensities.

  13. Particulate matter emission factors for almond harvest as a function of harvester speed.

    PubMed

    Faulkner, William B; Goodrich, L Barry; Botlaguduru, Venkata S V; Capareda, Sergio C; Parnell, Calvin B

    2009-08-01

    Almond harvest accounts for substantial particulate matter less than 10 microm in aerodynamic diameter (PM10) emissions in California each harvest season. This paper addresses the reduction of harvester ground speed from a standard 8 km/hr (5 mph) to 4 km/hr (2.5 mph) as a possible mitigation measure for reducing PM10 emissions. Ambient total suspended particulate (TSP) and PM10 sampling was conducted during harvest with alternating control (8 km/hr [5 mph]) and experimental (4 km/hr [2.5 mph]) treatments. On-site meteorological data were used in conjunction with both Industrial Source Complex-Short Term version 3 (ISCST3) and the American Meteorological Society/U.S. Environmental Protection Agency Regulatory Model (AERMOD) dispersion models to back-calculate emission rates from the measured concentrations. Baseline annual emission factors for nut pickup of 381 +/- 122 and 361 +/- 123 kg PM10/km2 x yr were determined using ISCST3 and AERMOD, respectively. Both of these values are substantially lower than the current PMIo emission factor for almond pickup of 4120 kg PM10/ km2 x yr. The particulate matter less than 2.5 microm in aerodynamic diameter (PM2.5) emission factors for nut pickup developed from this study were 25 +/- 8 kg PM2.5/km2 x yr and 24 +/- 8 kg PM10/km2 x yr were determined using ISCST3 and AERMOD, respectively. Reducing harvester speed resulted in an emissions reduction of 42% for TSP, but no differences were detected in emissions of PM10 and PM2.5. Differences detected in the emission factors developed using ISCST3 and AERMOD were not statistically significant, indicating that almond harvest emission factors previously developed using ISCST3 may be applied appropriately in AERMOD. PMID:19728488

  14. Monsoon harvests: the living legacies of rainwater harvesting systems in South India.

    PubMed

    Van Meter, Kimberly J; Basu, Nandita B; Tate, Eric; Wyckoff, Joseph

    2014-04-15

    Rainwater harvesting, a "soft path" approach toward water management, is increasingly recognized as a key strategy toward ensuring food security and alleviating problems of water scarcity. Interestingly this "modern" approach has been in use for millennia in numerous older civilizations. This article uses India as a case study to explore the social, economic, and environmental dimensions of agricultural rainwater harvesting ponds, and evaluates the viability of these centuries-old systems under current climate and population pressures. A holistic watershed-scale approach that accounts for trade-offs in water availability and socioeconomic wellbeing is recommended for assessing the sustainability of these systems. PMID:24575859

  15. Duck harvest on public hunting areas in California

    USGS Publications Warehouse

    Gilmer, D.S.; Hicks, J.M.; Fleskes, J.P.; Connelly, D.P.

    1989-01-01

    We summarized hunter visits and success, and the magnitude and species composition of the duck harvest recorded on California public hunting areas (PHAs) during 1950-87. Hunter visits and harvest increased during 1950-74 as new PHAs were added, then declined concurrently with duck populations. Of six geographic regions, the Sacramento Valley, with numerous PHAs and the largest duck concentrations, accounted for the largest portion of PHA hunter visits (28%) and harvest (35%). Duck population levels, regulations, and hunter numbers affected PHA hunter success. Success was highest during 1955-59 but declined with no consistent trend after 1960. Species vulnerability, abundance, distribution, and hunter preference affected harvest composition. Northern pintails, Anas acuta, averaged 27% of the PHA harvest but declined in importance after 1974. Green-winged teal, A. crecca, the most important species in southern regions, averaged 21% of the PHA harvest. Mallards, A. platyrhynchos, averaged 16% of the PHA harvest but increased in importance after 1974 to become the most common duck bagged after 1983. PHA harvest comprised a small (4-16%) portion of the total state harvest. However, this portion increased from 1950-70 because of increased hunter visits to new PHAs and after 1970 because hunter success on PHAs did not decline as on other areas. PHA hunters tended to harvest fewer preferred species and more vulnerable species, as proportions of total bag, than did other hunters. The continued decline in numbers of waterfowl hunters presents important challenges for management of waterfowl areas in California.

  16. Spatial assessment of conjunctive water harvesting potential in watershed systems

    NASA Astrophysics Data System (ADS)

    Sekar, I.; Randhir, T. O.

    2007-02-01

    SummaryWater harvesting can be used to minimize water loss and to augment water supplies in watershed systems. This effort is increasingly being recognized as critical in regions experiencing urbanization and facing uneven water supplies. Water harvesting requires a careful assessment of geographic locations in a watershed and evaluation of surface and groundwater hydrology. In this paper, we develop a spatially explicit method to evaluate costs of harvesting and potential benefits in water harvesting in the Taunton River Watershed in Eastern Massachusetts, USA. A spatial analysis is used to assess surface storage and groundwater recharge potentials in developed and undeveloped regions of the watershed. Distributed parameters used in the analysis include runoff coefficients, land use, soil properties, precipitation, aquifer, and land price. Prioritization maps were developed to characterize conjunctive harvesting potential that is based on benefits and costs. The results demonstrate that a spatially variable harvesting strategy can be used to minimize runoff loss and to augment water supplies. The potential harvest areas were clustered in specific locations that satisfy feasibility and economic criteria. In some subwatersheds, potential harvest locations were dispersed. A spatially variable approach that incorporates economic criteria to hydrologic assessment can be used to enhance efficiency related to water harvest and supply management. Given the increasing demand for clean water, a distributed and conjunctive harvesting strategy could be effective in several urbanizing watersheds. The model has potential for further extension into complex situations of biophysical and socioeconomic conditions at watershed level.

  17. Broadband energy harvesting using nonlinear 2-DOF configuration

    NASA Astrophysics Data System (ADS)

    Wu, Hao; Tang, Lihua; Avvari, Panduranga Vittal; Yang, Yaowen; Soh, Chee Kiong

    2013-04-01

    Vibration energy harvesting using piezoelectric material has received great research interest in the recent years. To enhance the performance of piezoelectric energy harvesters, one important concern is to increase their operating bandwidth. Various techniques have been proposed for broadband energy harvesting, such as the resonance tuning approach, the frequency up-conversion technique, the multi-modal harvesting and the nonlinear technique. Usually, a nonlinear piezoelectric energy harvester can be easily developed by introducing a magnetic field. Either mono-stable or bi-stable response can be achieved using different magnetic configurations. However, most of the research work for nonlinear piezoelectric energy harvesting has focused on the SDOF cantilever beam. A recently reported linear 2-DOF harvester can achieve two close resonant frequencies with significant power outputs. However, for this linear configuration, although a broader bandwidth can be achieved, there exists a deep valley in-between the two response peaks. The presence of the valley will greatly deteriorate the performance of the energy harvester. To overcome this limitation, a nonlinear 2-DOF piezoelectric energy harvester is proposed in this article. This nonlinear harvester is developed from its linear counterpart by incorporating a magnetic field using a pair of magnets. Experimental parametric study is carried out to investigate the behavior of such harvester. With different configurations, both mono-stable and bi-stable behaviors are observed and studied. An optimal configuration of the nonlinear harvester is thus obtained, which can achieve significantly wider bandwidth than the linear 2-DOF harvester and at the same time overcome its limitation.

  18. Development of a biomechanical energy harvester

    PubMed Central

    Li, Qingguo; Naing, Veronica; Donelan, J Maxwell

    2009-01-01

    Background Biomechanical energy harvesting–generating electricity from people during daily activities–is a promising alternative to batteries for powering increasingly sophisticated portable devices. We recently developed a wearable knee-mounted energy harvesting device that generated electricity during human walking. In this methods-focused paper, we explain the physiological principles that guided our design process and present a detailed description of our device design with an emphasis on new analyses. Methods Effectively harvesting energy from walking requires a small lightweight device that efficiently converts intermittent, bi-directional, low speed and high torque mechanical power to electricity, and selectively engages power generation to assist muscles in performing negative mechanical work. To achieve this, our device used a one-way clutch to transmit only knee extension motions, a spur gear transmission to amplify the angular speed, a brushless DC rotary magnetic generator to convert the mechanical power into electrical power, a control system to determine when to open and close the power generation circuit based on measurements of knee angle, and a customized orthopaedic knee brace to distribute the device reaction torque over a large leg surface area. Results The device selectively engaged power generation towards the end of swing extension, assisting knee flexor muscles by producing substantial flexion torque (6.4 Nm), and efficiently converted the input mechanical power into electricity (54.6%). Consequently, six subjects walking at 1.5 m/s generated 4.8 ± 0.8 W of electrical power with only a 5.0 ± 21 W increase in metabolic cost. Conclusion Biomechanical energy harvesting is capable of generating substantial amounts of electrical power from walking with little additional user effort making future versions of this technology particularly promising for charging portable medical devices. PMID:19549313

  19. Power management for energy harvesting wireless sensors

    NASA Astrophysics Data System (ADS)

    Arms, S. W.; Townsend, C. P.; Churchill, D. L.; Galbreath, J. H.; Mundell, S. W.

    2005-05-01

    The objective of this work was to demonstrate smart wireless sensing nodes capable of operation at extremely low power levels. These systems were designed to be compatible with energy harvesting systems using piezoelectric materials and/or solar cells. The wireless sensing nodes included a microprocessor, on-board memory, sensing means (1000 ohm foil strain gauge), sensor signal conditioning, 2.4 GHz IEEE 802.15.4 radio transceiver, and rechargeable battery. Extremely low power consumption sleep currents combined with periodic, timed wake-up was used to minimize the average power consumption. Furthermore, we deployed pulsed sensor excitation and microprocessor power control of the signal conditioning elements to minimize the sensors" average contribution to power draw. By sleeping in between samples, we were able to demonstrate extremely low average power consumption. At 10 Hz, current consumption was 300 microamps at 3 VDC (900 microwatts); at 5 Hz: 400 microwatts, at 1 Hz: 90 microwatts. When the RF stage was not used, but data were logged to memory, consumption was further reduced. Piezoelectric strain energy harvesting systems delivered ~2000 microwatts under low level vibration conditions. Output power levels were also measured from two miniature solar cells; which provided a wide range of output power (~100 to 1400 microwatts), depending on the light type & distance from the source. In summary, system power consumption may be reduced by: 1) removing the load from the energy harvesting & storage elements while charging, 2) by using sleep modes in between samples, 3) pulsing excitation to the sensing and signal conditioning elements in between samples, and 4) by recording and/or averaging, rather than frequently transmitting, sensor data.

  20. Enhanced vibration energy harvesting using nonlinear oscillations

    NASA Astrophysics Data System (ADS)

    Engel, Emily; Wei, Jiaying; Lee, Christopher L.

    2015-05-01

    Results for the design and testing of an electromagnetic device that converts ambient mechanical vibration into electricity are presented. The design of the device is based on an L-shaped beam structure which is tuned so that the first two natural frequencies have a near two-to-one ratio which is referred to as an internal resonance or autoparametic condition. It is shown that in contrast to single degree-of-freedom, linear-dynamics-based vibration harvesters which convert energy in a very narrow frequency band the prototype can generate power over an extended frequency range when subject to harmonic, base displacement excitation.

  1. Energy harvesting using a thermoelectric material

    SciTech Connect

    Nersessian, Nersesse; Carman, Gregory P.; Radousky, Harry B.

    2008-07-08

    A novel energy harvesting system and method utilizing a thermoelectric having a material exhibiting a large thermally induced strain (TIS) due to a phase transformation and a material exhibiting a stress induced electric field is introduced. A material that exhibits such a phase transformation exhibits a large increase in the coefficient of thermal expansion over an incremental temperature range (typically several degrees Kelvin). When such a material is arranged in a geometric configuration, such as, for a example, a laminate with a material that exhibits a stress induced electric field (e.g. a piezoelectric material) the thermally induced strain is converted to an electric field.

  2. Harvesting vibrations via 3D phononic isolators

    NASA Astrophysics Data System (ADS)

    Psarobas, Ioannis E.; Yannopapas, Vassilios; Matikas, Theodore E.

    2016-05-01

    We report on the existence of unidirectional phononic band gaps that may span over extended regions of the Brillouin zone and can find application in trapping elastic (acoustic) waves in properly designed multilayered 3D structures. Phononic isolators operate as a result of asymmetrical wave transmission through a slab of a crystallographic phononic structure with broken mirror symmetry. Due to the use of lossless materials in the crystal, the absorption rate is dramatically enhanced when the proposed isolator is placed next to a vibrational harvesting cell. xml:lang="fr"

  3. System for harvesting water wave energy

    DOEpatents

    Wang, Zhong Lin; Su, Yanjie; Zhu, Guang; Chen, Jun

    2016-07-19

    A generator for harvesting energy from water in motion includes a sheet of a hydrophobic material, having a first side and an opposite second side, that is triboelectrically more negative than water. A first electrode sheet is disposed on the second side of the sheet of a hydrophobic material. A second electrode sheet is disposed on the second side of the sheet of a hydrophobic material and is spaced apart from the first electrode sheet. Movement of the water across the first side induces an electrical potential imbalance between the first electrode sheet and the second electrode sheet.

  4. Thermoelectric energy harvesting with quantum dots.

    PubMed

    Sothmann, Björn; Sánchez, Rafael; Jordan, Andrew N

    2015-01-21

    We review recent theoretical work on thermoelectric energy harvesting in multi-terminal quantum-dot setups. We first discuss several examples of nanoscale heat engines based on Coulomb-coupled conductors. In particular, we focus on quantum dots in the Coulomb-blockade regime, chaotic cavities and resonant tunneling through quantum dots and wells. We then turn toward quantum-dot heat engines that are driven by bosonic degrees of freedom such as phonons, magnons and microwave photons. These systems provide interesting connections to spin caloritronics and circuit quantum electrodynamics. PMID:25549281

  5. Wideband energy harvesting using a combination of an optimized synchronous electric charge extraction circuit and a bistable harvester

    NASA Astrophysics Data System (ADS)

    Liu, W. Q.; Badel, A.; Formosa, F.; Wu, Y. P.; Agbossou, A.

    2013-12-01

    The challenge of variable vibration frequencies for energy harvesting calls for the development of wideband energy harvesters. Bistability has been proven to be a potential solution. Optimization of the energy extraction is another important objective for energy harvesting. Nonlinear synchronized switching techniques have demonstrated some of the best performances. This paper presents a novel energy harvesting solution which combines these two techniques: the OSECE (optimized synchronous electric charge extraction) technique is used along with a BSM (buckled-spring-mass) bistable generator to achieve wideband energy harvesting. The effect of the electromechanical coupling coefficient on the harvested power for the bistable harvester with the nonlinear energy extraction technique is discussed for the first time. The performances of the proposed solution for different levels of electromechanical coupling coefficients in the cases of chirp and noise excitations are compared against the performances of the bistable harvester with the standard technique. It is shown that the OSECE technique is a much better option for wideband energy harvesting than the standard circuit. Moreover, the harvested energy is drastically increased for all excitations in the case of low electromechanical coupling coefficients. When the electromechanical coupling coefficient is high, the performance of the OSECE technique is not as good as the standard circuit for forward sweeps, but superior for the reverse sweep and band-limited noise cases. However, considering that real excitation signals are more similar to noise signals, the OSECE technique enhances the performance.

  6. Water quality management of rooftop rainwater harvesting systems.

    PubMed

    Abbasi, Tasneem; Abbasi, S A

    2009-10-01

    The ancient technique of harvesting rainwater falling on rooftops, which had been forgotten after the advent of large-scale centralized water resource systems like dam-based reservoirs, has staged a global comeback in the post-modern era. It is expected that in the near future all dwellings everywhere will be equipped to harvest and use rainwater. Such widespread use of rooftop rainwater harvesting makes it very important that the water quality aspects associated with it are clearly understood and managed. The present paper addresses the related issues. The pathways by which pollutants can enter in a rainwater harvest have been traced and the strategies to manage the water quality, at pre-harvest as well as post-harvest stages, have been discussed. PMID:21117427

  7. Models for 31-mode PVDF energy harvester for wearable applications.

    PubMed

    Zhao, Jingjing; You, Zheng

    2014-01-01

    Currently, wearable electronics are increasingly widely used, leading to an increasing need of portable power supply. As a clean and renewable power source, piezoelectric energy harvester can transfer mechanical energy into electric energy directly, and the energy harvester based on polyvinylidene difluoride (PVDF) operating in 31-mode is appropriate to harvest energy from human motion. This paper established a series of theoretical models to predict the performance of 31-mode PVDF energy harvester. Among them, the energy storage one can predict the collected energy accurately during the operation of the harvester. Based on theoretical study and experiments investigation, two approaches to improve the energy harvesting performance have been found. Furthermore, experiment results demonstrate the high accuracies of the models, which are better than 95%. PMID:25114981

  8. Multi-source energy harvester for wildlife tracking

    NASA Astrophysics Data System (ADS)

    Wu, You; Zuo, Lei; Zhou, Wanlu; Liang, Changwei; McCabe, Michael

    2014-03-01

    Sufficient power supply to run GPS machinery and transmit data on a long-term basis remains to be the key challenge for wildlife tracking technology. Traditional way of replacing battery periodically is not only time and money consuming but also dangerous to live-trapping wild animals. In this paper, an innovative wildlife tracking device with multi-source energy harvester with advantage of high efficiency and reliability is investigated and developed. This multi-source energy harvester entails a solar energy harvester and an innovative rotational electromagnetic energy harvester is mounted on the "wildlife tracking collar" which will remarkably extend the duration of wild life tracking. A feedforward and feedback control of DC-DC converter circuit is adopted to passively realize the Maximum Power Point Tracking (MPPT) logic for the solar energy harvester. The rotational electromagnetic energy harvester can mechanically rectify the irregular bidirectional motion into unidirectional motion has been modeled and demonstrated.

  9. Energy harvesting and wireless energy transmission for embedded sensor nodes

    NASA Astrophysics Data System (ADS)

    Farinholt, Kevin; Taylor, Stuart; Miller, Nathan; Sifuentes, Wilfredo; Moro, Erik; Park, Gyuhae; Farrar, Charles; Flynn, Eric; Mascarenas, David; Todd, Michael

    2009-03-01

    In this paper, we present experimental investigations using energy harvesting and wireless energy transmission to operate embedded structural health monitoring sensor nodes. The goal of this study is to develop sensing systems that can be permanently embedded within a host structure without the need for an on-board power source. With this approach the required energy will be harvested from the ambient environment, or periodically delivered by a RF energy source to supplement conventional harvesting approaches. This approach combines several transducer types to harvest energy from multiple sources, providing a more robust solution that does not rely on a single energy source. Both piezoelectric and thermoelectric transducers are considered as energy harvesters to extract the ambient energy commonly available on civil structures such as bridges. Methods of increasing the efficiency, energy storage medium, target applications and the integrated use of energy harvesting sources with wireless energy transmission will be discussed.

  10. Piezomagnetoelastic broadband energy harvester: Nonlinear modeling and characterization

    NASA Astrophysics Data System (ADS)

    Aravind Kumar, K.; Ali, S. F.; Arockiarajan, A.

    2015-11-01

    Piezomagnetoelastic energy harvesters are one among the widely explored configurations to improve the broadband characteristics of vibration energy harvesters. Such nonlinear harvesters follow a Moon beam model with two magnets at the base and one at the tip of the beam. The present article develops a geometric nonlinear mathematical model for the broadband piezomagnetoelastic energy harvester. The electromechanical coupling and the nonlinear magnetic potential equations are developed from the dimensional system parameters to describe the nonlinear dynamics exhibited by the system. The developed model is capable of characterizing the monostable, bistable and tristable operating regimes of the piezomagnetoelastic energy harvester, which are not explicit in the Duffing representation of the system. Bifurcations and attractor motions are analyzed as nonlinear functions of the distance between base magnets and the field strength of the tip magnet. The model is further used to characterize the potential wells and stable states, with due focus on the performance of the system in broadband energy harvesting.

  11. Models for 31-Mode PVDF Energy Harvester for Wearable Applications

    PubMed Central

    Zhao, Jingjing; You, Zheng

    2014-01-01

    Currently, wearable electronics are increasingly widely used, leading to an increasing need of portable power supply. As a clean and renewable power source, piezoelectric energy harvester can transfer mechanical energy into electric energy directly, and the energy harvester based on polyvinylidene difluoride (PVDF) operating in 31-mode is appropriate to harvest energy from human motion. This paper established a series of theoretical models to predict the performance of 31-mode PVDF energy harvester. Among them, the energy storage one can predict the collected energy accurately during the operation of the harvester. Based on theoretical study and experiments investigation, two approaches to improve the energy harvesting performance have been found. Furthermore, experiment results demonstrate the high accuracies of the models, which are better than 95%. PMID:25114981

  12. Flexible Piezoelectric Energy Harvesting from Mouse Click Motions

    PubMed Central

    Cha, Youngsu; Hong, Jin; Lee, Jaemin; Park, Jung-Min; Kim, Keehoon

    2016-01-01

    In this paper, we study energy harvesting from the mouse click motions of a robot finger and a human index finger using a piezoelectric material. The feasibility of energy harvesting from mouse click motions is experimentally and theoretically assessed. The fingers wear a glove with a pocket for including the piezoelectric material. We model the energy harvesting system through the inverse kinematic framework of parallel joints in a finger and the electromechanical coupling equations of the piezoelectric material. The model is validated through energy harvesting experiments in the robot and human fingers with the systematically varying load resistance. We find that energy harvesting is maximized at the matched load resistance to the impedance of the piezoelectric material, and the harvested energy level is tens of nJ. PMID:27399705

  13. Variance estimation for the Federal Waterfowl Harvest Surveys

    USGS Publications Warehouse

    Geissler, P.H.

    1988-01-01

    The Federal Waterfowl Harvest Surveys provide estimates of waterfowl harvest by species for flyways and states, harvests of most other migratory game bird species (by waterfowl hunters), crippling losses for ducks, geese, and coots, days hunted, and bag per hunter. The Waterfowl Hunter Questionnaire Survey separately estimates the harvest of ducks and geese using cluster samples of hunters who buy duck stamps at sample post offices. The Waterfowl Parts Collection estimates species, age, and sex ratios from parts solicited from successful hunters who responded to the Waterfowl Hunter Questionnaire Survey in previous years. These ratios are used to partition the duck and goose harvest into species, age, and sex specific harvest estimates. Annual estimates are correlated because successful hunters who respond to the Questionnaire Survey in one year may be asked to contribute to the Parts Collection for the next three years. Bootstrap variance estimates are used because covariances among years are difficult to estimate.

  14. Flexible Piezoelectric Energy Harvesting from Mouse Click Motions.

    PubMed

    Cha, Youngsu; Hong, Jin; Lee, Jaemin; Park, Jung-Min; Kim, Keehoon

    2016-01-01

    In this paper, we study energy harvesting from the mouse click motions of a robot finger and a human index finger using a piezoelectric material. The feasibility of energy harvesting from mouse click motions is experimentally and theoretically assessed. The fingers wear a glove with a pocket for including the piezoelectric material. We model the energy harvesting system through the inverse kinematic framework of parallel joints in a finger and the electromechanical coupling equations of the piezoelectric material. The model is validated through energy harvesting experiments in the robot and human fingers with the systematically varying load resistance. We find that energy harvesting is maximized at the matched load resistance to the impedance of the piezoelectric material, and the harvested energy level is tens of nJ. PMID:27399705

  15. Modeling of a honeycomb-shaped pyroelectric energy harvester for human body heat harvesting

    NASA Astrophysics Data System (ADS)

    Kim, Myoung-Soo; Jo, Sung-Eun; Ahn, Hye-Rin; Kim, Yong-Jun

    2015-06-01

    Pyroelectric conversion can be used for thermal energy harvesting in lieu of thermoelectric conversion. In the case of human body energy harvesting, the general pyroelectric energy harvester (PEH) cannot be applied because the weak body heat can hardly penetrate the protecting layer to reach the pyroelectric material. This paper presents the realization of a honeycomb-shaped PEH (H-PEH) and a modeling method of the electrode and hole areas. The fabricated H-PEH successfully generated electrical energy using human body heat. The H-PEH with a 1:1.5 electrode-and-hole area ratio showed the best performance. To verify the human energy harvesting, we evaluated the characteristics of conventional PEH and H-PEH when body heat was used as a heat source. The maximum power of the H-PEH was 0.06 and 0.16 μW at wind velocities of 2 and 4 m s-1, respectively. These output power values of the H-PEH were 200 and 224% larger than those of the PEH, respectively, according to the wind velocity.

  16. Risk factors of musculoskeletal disorders among oil palm fruit harvesters during early harvesting stage.

    PubMed

    Ng, Yee Guan; Mohd Tamrin, Shamsul Bahri; Mohd Yusoff, Irwan Syah; Hashim, Zailina; Deros, Baba M D; Abu Bakar, Shahriman; How, Vivien

    2015-01-01

    This cross-sectional study intends to investigate the associations of musculoskeletal disorders (MSDs) among foreign labourers on a socio-economic background, occupational exposure, social lifestyle, and postures adopted during harvesting tasks. A total of 446 male respondents (263 FFB cutters; 183 FFB collectors) were studied using an interview-assisted questionnaire. OWAS was used to determine the severity of awkward posture based on videos of harvesting tasks recorded for each respondent. Analysis found that increasingly educated respondents had higher risk of developing MSDs. Shorter daily work duration and longer resting duration appear to increase the risk of neck and shoulder disorders among harvesters, which may be attributable to organizational work design. Awkward posture was a particularly significant risk factor of MSDs among FFB collectors. Among the results of the study, occupational exposure, postures and certain socio-demographic backgrounds explained some, but not all, the risk factor of MSDs among harvesters. An in-depth investigation, preferably a longitudinal study investigating the dynamic of work activities and other risk factors, such as psychosocial risk factors, are recommended. PMID:26094525

  17. Vine-Kill Treatment and Harvest Date Have Persistant Effects on Tuber Physiology After Harvest

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Potato tuber development follows a genetically programmed progression from tuber initiation to maturation. Most grower activities nurture this process, but vine kill and harvest are exceptions that have the potential to affect the quality of the crop. Experiments conducted for two years determined t...

  18. Investigating why recycling gravity harvested algae increases harvestability and productivity in high rate algal ponds.

    PubMed

    Park, J B K; Craggs, R J; Shilton, A N

    2013-09-15

    It has previously been shown that recycling gravity harvested algae promotes Pediastrum boryanum dominance and improves harvestability and biomass production in pilot-scale High Rate Algal Ponds (HRAPs) treating domestic wastewater. In order to confirm the reproducibility of these findings and investigate the mechanisms responsible, this study utilized twelve 20 L outdoor HRAP mesocosms operated with and without algal recycling. It then compared the recycling of separated solid and liquid components of the harvested biomass against un-separated biomass. The work confirmed that algal recycling promoted P. boryanum dominance, improved 1 h-settleability by >20% and increased biomass productivity by >25% compared with controls that had no recycling. With regard to the improved harvestability, of particular interest was that recycling the liquid fraction alone caused a similar improvement in settleability as recycling the solid fraction. This may be due to the presence of extracellular polymeric substances in the liquid fraction. While there are many possible mechanisms that could account for the increased productivity with algal recycling, all but two were systematically eliminated: (i) the mean cell residence time was extended thereby increasing the algal concentration and more fully utilizing the incident sunlight and, (ii) the relative proportions of algal growth stages (which have different specific growth rates) was changed, resulting in a net increase in the overall growth rate of the culture. PMID:23866138

  19. Effects of horseshoe crab harvest in delaware bay on red knots: Are harvest restrictions working?

    USGS Publications Warehouse

    Niles, L.J.; Bart, J.; Sitters, H.P.; Dey, A.D.; Clark, K.E.; Atkinson, P.W.; Baker, A.J.; Bennett, K.A.; Kalasz, K.S.; Clark, N.A.; Clark, J.; Gillings, S.; Gates, A.S.; Gonzalez, P.M.; Hernandez, D.E.; Minton, C.D.T.; Morrison, R.I.G.; Porter, R.R.; Ross, R.K.; Veitch, C.R.

    2009-01-01

    Each May, red knots (Calidris canutus rufa) congregate in Delaware Bay during their northward migration to feed on horseshoe crab eggs (Limulus polyphemus) and refuel for breeding in the Arctic. During the 1990s, the Delaware Bay harvest of horseshoe crabs for bait increased 10-fold, leading to a more than 90% decline in the availability of their eggs for knots. The proportion of knots achieving weights of more than 180 grams by 26-28 May, their main departure period, dropped from 0.6-0.8 to 0.14-0.4 over 1997-2007. During the same period, the red knot population stopping in Delaware Bay declined by more than 75%, in part because the annual survival rate of adult knots wintering in Tierra del Fuego declined. Despite restrictions, the 2007 horseshoe crab harvest was still greater than the 1990 harvest, and no recovery of knots was detectable. We propose an adaptive management strategy with recovery goals and annual monitoring that, if adopted, will both allow red knot and horseshoe crab populations to recover and permit a sustainable harvest of horseshoe crabs.

  20. 77 FR 17353 - Migratory Bird Subsistence Harvest in Alaska; Harvest Regulations for Migratory Birds in Alaska...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-26

    ... Register on August 16, 2002 (67 FR 53511) and most recently on March 29, 2011 (76 FR 17353). Recent Federal... 8, 2011 (76 FR 19876). While that proposed rule dealt primarily with the regulatory process for... FR 68264) a proposed rule that provided our proposed migratory bird subsistence harvest...

  1. Review of the application of energy harvesting in buildings

    NASA Astrophysics Data System (ADS)

    Matiko, J. W.; Grabham, N. J.; Beeby, S. P.; Tudor, M. J.

    2014-01-01

    This review presents the state of the art of the application of energy harvesting in commercial and residential buildings. Electromagnetic (optical and radio frequency), kinetic, thermal and airflow-based energy sources are identified as potential energy sources within buildings and the available energy is measured in a range of buildings. Suitable energy harvesters are discussed and the available and the potential harvested energy calculated. Calculations based on these measurements, and the technical specifications of state-of-the-art harvesters, show that typical harvested powers are: (1) indoor solar cell (active area of 9 cm2, volume of 2.88 cm3): ˜300 µW from a light intensity of 1000 lx; (2) thermoelectric harvester (volume of 1.4 cm3): 6 mW from a thermal gradient of 25 °C (3) periodic kinetic energy harvester (volume of 0.15 cm3): 2 µW from a vibration acceleration of 0.25 m s-2 at 45 Hz (4) electromagnetic wave harvester (13 cm antenna length and conversion efficiency of 0.7): 1 µW with an RF source power of -25 dBm; and (5) airflow harvester (wind turbine blade of 6 cm diameter and generator efficiency of 0.41): 140 mW from an airflow of 8 m s-1. These results highlight the high potential of energy harvesting technology in buildings and the relative attractions of various harvester technologies. The harvested power could either be used to replace batteries or to prolong the life of rechargeable batteries for low-power (˜1 mW) electronic devices.

  2. A full body mathematical model of an oil palm harvester

    NASA Astrophysics Data System (ADS)

    Tumit, NP; Rambely, A. S.; BMT, Shamsul; Shahriman A., B.; Ng Y., G.; Deros, B. M.; Zailina, H.; Goh Y., M.; Arumugam, Manohar; Ismail I., A.; Abdul Hafiz A., R.

    2015-09-01

    The main purpose of this article is to develop a mathematical model of human body during harvesting via Kane's method. This paper is an extension model of previous biomechanical model representing a harvester movement during harvesting a Fresh Fruit Bunch (FFB) from a palm oil tree. The ten segment model consists of foot, leg, trunk, the head and the arms segment. Finally, the inverse dynamic equations are represented in a matrix form.

  3. Do biomass harvesting guidelines influence herpetofauna following harvests of logging residues for renewable energy?.

    PubMed

    Fritts, Sarah; Moorman, Christopher; Grodsky, Steven; Hazel, Dennis; Homyack, Jessica; Farrell, Chris; Castleberry, Steven

    2016-04-01

    Forests are a major supplier of renewable energy; however, gleaning logging residues for use as woody biomass feedstock could negatively alter habitat for species dependent on downed wood. Biomass Harvesting Guidelines (BHGs) recommend retaining a portion of woody biomass on the forest floor following harvest. Despite BHGs being developed to help ensure ecological sustainability, their contribution to biodiversity has not been evaluated experimentally at operational scales. We compared herpetofauanal evenness, diversity, and richness and abundance of Anaxyrus terrestris and Gastrophryne carolinensis among six treatments that varied in volume and spatial arrangement of woody biomass retained after clearcutting loblolly pine (Pinus taeda) plantations in North Carolina, USA (n = 4), 2011-2014 and Georgia (n = 4), USA 2011-2013. Treatments were: (1) biomass harvest with no BHGs, (2) 15% retention with biomass clustered, (3) 15% retention with biomass dispersed, (4) 30% retention with biomass clustered, (5) 30% retention with biomass dispersed, and (6) no biomass harvest. We captured individuals with drift fence arrays and compared evenness, diversity, and richness metrics among treatments with repeated-measure, linear mixed-effects models. We determined predictors of A. terrestris and G. carolinensis abundances using a priori candidate N-mixture models with woody biomass volume, vegetation structure, and groundcover composition as covariates. We had 206 captures of 25 reptile species and 8710 captures of 17 amphibian species during 53690 trap nights. Herpetofauna diversity, evenness, and richness were similar among treatments. A. terrestris abundance was negatively related to volume of retained woody biomass in treatment units in North Carolina in 2013. G. carolinensis abundance was positively related with volume of retained woody debris in treatment units in Georgia in 2012. Other relationships between A. terrestris and G. carolinensis abundances and habitat metrics

  4. Synchronized switch harvesting applied to piezoelectric flags

    NASA Astrophysics Data System (ADS)

    Piñeirua, Miguel; Michelin, Sébastien; Vasic, Dejan; Doaré, Olivier

    2016-08-01

    In this article the energy transfer between a flow and a fluttering piezoelectric plate is investigated. In particular, the benefits of the use of a synchronized switch harvesting on inductor (SSHI) circuit are studied. Both wind tunnel experiments and numerical simulations are conducted in order to analyze the influence of the switching process on the dynamics and the efficiency of the system. Numerical simulations consist of a weakly nonlinear model of a plate in axial flow equipped with a single pair of piezoelectric patches, discretized using a Galerkin method where basis functions are the modes of the plate in vacuum. The discretized model is then integrated in time. The results presented in this paper show that a significant improvement of the harvested energy can be obtained using SSHI circuits compared to basic resistive circuits. It is also shown that for strongly coupled systems, the switching process inherent to he SSHI circuit has a significant impact on the dynamics of the flag, which tends to decrease the relative efficiency gain.

  5. Sustainable Harvest for Food and Fuel

    SciTech Connect

    Raymond R. Grosshans; Kevin M. Kostelnik; Jacob J. Jacobson

    2007-12-01

    The DOE Biomass Program recently implemented the Biofuels Initiative, or 30x30 program, with the dual goal of reducing U.S. dependence on foreign oil by making cellulosic ethanol cost competitive with gasoline by 2012 and by replacing 30 percent of gasoline consumption with biofuels by 2030. Experience to date with increasing ethanol production suggests that it distorts agricultural markets and therefore raises concerns about the sustainability of the DOE 30x30 effort: Can the U.S. agricultural system produce sufficient feedstocks for biofuel production and meet the food price and availability expectations of American consumers without causing environmental degradation that would curtail the production of both food and fuel? Efforts are underway to develop computer-based modeling tools that address this concern and support the DOE 30x30 goals. Beyond technical agronomic and economic concerns, however, such models must account for the publics’ growing interest in sustainable agriculture and in the reduction of greenhouse gas emissions. This paper discusses ongoing work at the Center for Advanced Energy Studies that investigates the potential consequences and long-term sustainability of projected biomass harvests by identifying and incorporating “sustainable harvest indicators” in a computer modeling strategy.

  6. Jumping-droplet electrostatic energy harvesting

    NASA Astrophysics Data System (ADS)

    Miljkovic, Nenad; Preston, Daniel J.; Enright, Ryan; Wang, Evelyn N.

    2014-07-01

    Micro- and nanoscale wetting phenomena have been an active area of research due to its potential for improving engineered system performance involving phase change. With the recent advancements in micro/nanofabrication techniques, structured surfaces can now be designed to allow condensing coalesced droplets to spontaneously jump off the surface due to the conversion of excess surface energy into kinetic energy. In addition to being removed at micrometric length scales (˜10 μm), jumping water droplets also attain a positive electrostatic charge (˜10-100 fC) from the hydrophobic coating/condensate interaction. In this work, we take advantage of this droplet charging to demonstrate jumping-droplet electrostatic energy harvesting. The charged droplets jump between superhydrophobic copper oxide and hydrophilic copper surfaces to create an electrostatic potential and generate power during formation of atmospheric dew. We demonstrated power densities of ˜15 pW/cm2, which, in the near term, can be improved to ˜1 μW/cm2. This work demonstrates a surface engineered platform that promises to be low cost and scalable for atmospheric energy harvesting and electric power generation.

  7. Piezoelectric energy harvesting in internal fluid flow.

    PubMed

    Lee, Hyeong Jae; Sherrit, Stewart; Tosi, Luis Phillipe; Walkemeyer, Phillip; Colonius, Tim

    2015-01-01

    We consider piezoelectric flow energy harvesting in an internal flow environment with the ultimate goal powering systems such as sensors in deep oil well applications. Fluid motion is coupled to structural vibration via a cantilever beam placed in a converging-diverging flow channel. Two designs were considered for the electromechanical coupling: first; the cantilever itself is a piezoelectric bimorph; second; the cantilever is mounted on a pair of flextensional actuators. We experimentally investigated varying the geometry of the flow passage and the flow rate. Experimental results revealed that the power generated from both designs was similar; producing as much as 20 mW at a flow rate of 20 L/min. The bimorph designs were prone to failure at the extremes of flow rates tested. Finite element analysis (FEA) showed fatigue failure was imminent due to stress concentrations near the bimorph's clamped region; and that robustness could be improved with a stepped-joint mounting design. A similar FEA model showed the flextensional-based harvester had a resonant frequency of around 375 Hz and an electromechanical coupling of 0.23 between the cantilever and flextensional actuators in a vacuum. These values; along with the power levels demonstrated; are significant steps toward building a system design that can eventually deliver power in the Watts range to devices down within a well. PMID:26473879

  8. Vein harvesting and techniques for infrainguinal bypass.

    PubMed

    Albäck, Anders; Saarinen, Eva; Venermo, Maarit

    2016-04-01

    In order to achieve good long term results after bypass surgery, alongside with good inflow and outflow arteries, the bypass graft material also has an important role. The best patency and limb salvage rates are achieved with autologous vein. If great saphenous vein is not available, acceptable long-term results can be achieved with arm veins and lesser saphenous vein. The quality and size of the vein are important. A small-caliber vein, increased wall thickness, postphlebitic changes and varicosities are associated with a risk of early failure. Preoperative vein mapping with ultrasound reduces readmissions and postoperative surgical site infections. During the mapping, the vein to be used and its main tributaries are marked with a permanent marker pen. To reduce wound complication rates we recommend bridged incisions in vein harvesting. Endoscopic vein harvesting seems to have no benefit compared to open techniques in lower limb bypasses, and has been associated with higher risk of primary patency loss at one year. With deep tunneling of the graft the problems caused by wound infection can be avoided. PMID:26837257

  9. Ferrofluid based micro-electrical energy harvesting

    NASA Astrophysics Data System (ADS)

    Purohit, Viswas; Mazumder, Baishakhi; Jena, Grishma; Mishra, Madhusha; Materials Department, University of California, Santa Barbara, CA93106 Collaboration

    2013-03-01

    Innovations in energy harvesting have seen a quantum leap in the last decade. With the introduction of low energy devices in the market, micro energy harvesting units are being explored with much vigor. One of the recent areas of micro energy scavenging is the exploitation of existing vibrational energy and the use of various mechanical motions for the same, useful for low power consumption devices. Ferrofluids are liquids containing magnetic materials having nano-scale permanent magnetic dipoles. The present work explores the possibility of the use of this property for generation of electricity. Since the power generation is through a liquid material, it can take any shape as well as response to small acceleration levels. In this work, an electromagnet-based micropower generator is proposed to utilize the sloshing of the ferrofluid within a controlled chamber which moves to different low frequencies. As compared to permanent magnet units researched previously, ferrofluids can be placed in the smallest of containers of different shapes, thereby giving an output in response to the slightest change in motion. Mechanical motion from 1- 20 Hz was able to give an output voltage in mV's. In this paper, the efficiency and feasibility of such a system is demonstrated.

  10. Flow Energy Piezoelectric Bimorph Nozzle Harvester

    NASA Technical Reports Server (NTRS)

    Sherrit, Stewart; Lee, Hyeong Jae; Kim, Namhyo; Sun, Kai; Corbett, Gary; Walkemeyer, Phillip; Hasenoehrl, Jennifer; Hall, Jeffery L.; Colonius, Tim; Tosi, Luis Phillipe; Arrazola, Alvaro

    2014-01-01

    There is a need for a long-life power generation scheme that could be used downhole in an oil well to produce 1 Watt average power. There are a variety of existing or proposed energy harvesting schemes that could be used in this environment but each of these has its own limitations. The vibrating piezoelectric structure is in principle capable of operating for very long lifetimes (decades) thereby possibly overcoming a principle limitation of existing technology based on rotating turbo-machinery. In order to determine the feasibility of using piezoelectrics to produce suitable flow energy harvesting, we surveyed experimentally a variety of nozzle configurations that could be used to excite a vibrating piezoelectric structure in such a way as to enable conversion of flow energy into useful amounts of electrical power. These included reed structures, spring mass-structures, drag and lift bluff bodies and a variety of nozzles with varying flow profiles. Although not an exhaustive survey we identified a spline nozzle/piezoelectric bimorph system that experimentally produced up to 3.4 mW per bimorph. This paper will discuss these results and present our initial analyses of the device using dimensional analysis and constitutive electromechanical modeling. The analysis suggests that an order-of-magnitude improvement in power generation from the current design is possible.

  11. Quantum mechanical light harvesting mechanisms in photosynthesis

    NASA Astrophysics Data System (ADS)

    Scholes, Gregory

    2012-02-01

    More than 10 million billion photons of light strike a leaf each second. Incredibly, almost every red-coloured photon is captured by chlorophyll pigments and initiates steps to plant growth. Last year we reported that marine algae use quantum mechanics in order to optimize photosynthesis [1], a process essential to its survival. These and other insights from the natural world promise to revolutionize our ability to harness the power of the sun. In a recent review [2] we described the principles learned from studies of various natural antenna complexes and suggested how to utilize that knowledge to shape future technologies. We forecast the need to develop ways to direct and regulate excitation energy flow using molecular organizations that facilitate feedback and control--not easy given that the energy is only stored for a billionth of a second. In this presentation I will describe new results that explain the observation and meaning of quantum-coherent energy transfer. [4pt] [1] Elisabetta Collini, Cathy Y. Wong, Krystyna E. Wilk, Paul M. G. Curmi, Paul Brumer, and Gregory D. Scholes, ``Coherently wired light-harvesting in photosynthetic marine algae at ambient temperature'' Nature 463, 644-648 (2010).[0pt] [2] Gregory D. Scholes, Graham R. Fleming, Alexandra Olaya-Castro and Rienk van Grondelle, ``Lessons from nature about solar light harvesting'' Nature Chem. 3, 763-774 (2011).

  12. Piezoelectric Energy Harvesting in Internal Fluid Flow

    PubMed Central

    Lee, Hyeong Jae; Sherrit, Stewart; Tosi, Luis Phillipe; Walkemeyer, Phillip; Colonius, Tim

    2015-01-01

    We consider piezoelectric flow energy harvesting in an internal flow environment with the ultimate goal powering systems such as sensors in deep oil well applications. Fluid motion is coupled to structural vibration via a cantilever beam placed in a converging-diverging flow channel. Two designs were considered for the electromechanical coupling: first; the cantilever itself is a piezoelectric bimorph; second; the cantilever is mounted on a pair of flextensional actuators. We experimentally investigated varying the geometry of the flow passage and the flow rate. Experimental results revealed that the power generated from both designs was similar; producing as much as 20 mW at a flow rate of 20 L/min. The bimorph designs were prone to failure at the extremes of flow rates tested. Finite element analysis (FEA) showed fatigue failure was imminent due to stress concentrations near the bimorph’s clamped region; and that robustness could be improved with a stepped-joint mounting design. A similar FEA model showed the flextensional-based harvester had a resonant frequency of around 375 Hz and an electromechanical coupling of 0.23 between the cantilever and flextensional actuators in a vacuum. These values; along with the power levels demonstrated; are significant steps toward building a system design that can eventually deliver power in the Watts range to devices down within a well. PMID:26473879

  13. Momentum harvesting techniques for solar system travel

    NASA Technical Reports Server (NTRS)

    Willoughby, Alan J.

    1990-01-01

    Astronomers are lately estimating there are 400,000 Earth visiting asteroids larger than 100 meters in diameter. These asteroids are accessible sources of building materials, propellants, oxygen, water, and minerals which also constitute a huge momentum reserve, potentially usable for travel throughout the solar system. To use this momentum, these stealthy objects must be tracked and the extraction of the momentum wanted must be learned. Momentum harvesting by momentum transfer from asteroid to spacecraft, and by using the momentum of the extraterrestrial material to help deliver itself to the destination are discussed. A net and tether concept is the suggested means of asteroid capture, the basic momentum exchange process. The energy damping characteristics of the tether will determine the velocity mismatch that can be tolerated, and hence the amount of momentum that can be harvested per capture. As it plays out of its reel, drag on the tether steadily accelerates the spacecraft. A variety of concepts for riding and using the asteroid after capture are discussed. The hitchhiker uses momentum transfer only. The beachcomber, the caveman, the swinger, the prospector, and the rock wrecker also take advantage of raw asteroidal materials. The chemist and the hijacker go further, they process the asteroid into propellant. Or, an 'asteroid railway system' could evolve with each hijacked asteroid becoming a scheduled train. Travelers could board the space railway system assured that water, oxygen, and propellants await them.

  14. Flow energy piezoelectric bimorph nozzle harvester

    NASA Astrophysics Data System (ADS)

    Sherrit, Stewart; Lee, Hyeong Jae; Walkemeyer, Phillip; Hasenoehrl, Jennifer; Hall, Jeffrey L.; Colonius, Tim; Tosi, Luis Phillipe; Arrazola, Alvaro; Kim, Namhyo; Sun, Kai; Corbett, Gary

    2014-04-01

    There is a need for a long-life power generation scheme that could be used downhole in an oil well to produce 1 Watt average power. There are a variety of existing or proposed energy harvesting schemes that could be used in this environment but each of these has its own limitations. The vibrating piezoelectric structure is in principle capable of operating for very long lifetimes (decades) thereby possibly overcoming a principle limitation of existing technology based on rotating turbo-machinery. In order to determine the feasibility of using piezoelectrics to produce suitable flow energy harvesting, we surveyed experimentally a variety of nozzle configurations that could be used to excite a vibrating piezoelectric structure in such a way as to enable conversion of flow energy into useful amounts of electrical power. These included reed structures, spring mass-structures, drag and lift bluff bodies and a variety of nozzles with varying flow profiles. Although not an exhaustive survey we identified a spline nozzle/piezoelectric bimorph system that experimentally produced up to 3.4 mW per bimorph. This paper will discuss these results and present our initial analyses of the device using dimensional analysis and constitutive electromechanical modeling. The analysis suggests that an order-of-magnitude improvement in power generation from the current design is possible.

  15. Nonlinearities in energy-harvesting media

    NASA Astrophysics Data System (ADS)

    Andrews, David L.; Jenkins, Robert D.

    2001-07-01

    Both in natural photosynthetic systems and also their molecularly engineered mimics, energy is generally transferred to the sites of its chemical storage from other sites of primary optical excitation. This migration process generally entails a number of steps, frequently involving intermediary chromophore units, with each step characterised by high efficiency and rapidity. Energy thereby accrues at reaction centres where its chemical storage occurs. At high levels of irradiation, energy harvesting material can exhibit novel forms of optical nonlinearity. Such behaviour is associated with the direct pooling of excitation energy, enabling secondary acceptors to undergo transitions to states whose energy equals that of two or more input photons, subject to decay losses. Observations of this kind have now been made on a variety of materials, ranging from photoactive dyes, through fullerene derivatives, to lanthanide doped crystals. Recently developed theory has established the underlying principles and links between the modes of operation of these systems. Key factors include the chromophore layout and geometry, electronic structure and optical selection rules. Mesoscopic symmetry, especially in photosynthetic pigment arrays and also in their dendrimeric mimics, is here linked to the transient establishment of excitons. The involvement of excitons in energy harvesting is nonetheless substantially compromised by local disorder. The interplay of these factors in photoactive materials design is discussed in the context of new materials for operation with intense laser light.

  16. Sustainable Harvest for Food and Fuel

    SciTech Connect

    Grosshans, Raymond R.; Kostelnik, Kevin, M.; Jacobson, Jacob J.

    2007-04-01

    The DOE Biomass Program recently implemented the Biofuels Initiative, or 30x30 program, with the dual goal of reducing U.S. dependence on foreign oil by making cellulosic ethanol cost competitive with gasoline by 2012 and by replacing 30 percent of gasoline consumption with biofuels by 2030. Experience to date with increasing ethanol production suggests that it distorts agricultural markets and therefore raises concerns about the sustainability of the DOE 30 X 30 effort: Can the U.S. agricultural system produce sufficient feedstocks for biofuel production and meet the food price and availability expectations of American consumers without causing environmental degradation that would curtail the production of both food and fuel? Efforts are underway to develop computer-based modeling tools that address this concern and support the DOE 30 X 30 goals. Beyond technical agronomic and economic concerns, however, such models must account for the publics’ growing interest in sustainable agriculture and in the mitigation of predicted global climate change. This paper discusses ongoing work at the Center for Advanced Energy Studies that investigates the potential consequences and long-term sustainability of projected biomass harvests by identifying and incorporating “sustainable harvest indicators” in a computer modeling strategy.

  17. A Nonlinear Energy Sink with Energy Harvester

    NASA Astrophysics Data System (ADS)

    Kremer, Daniel

    The transfer of energy between systems is a natural process, manifesting in many different ways. In engineering transferable energy can be considered wanted or unwanted. Specifically in mechanical systems, energy transfer can occur as unwanted vibrations, passing from a source to a receiver. In electrical systems, energy transfer can be desirable, where energy from a source may be used elsewhere. This work proposes a method to combine the two, converting unwanted mechanical energy into useable electrical energy. A nonlinear energy sink (NES) is a vibration absorber that passively localizes vibrational energy, removing mechanical energy from a primary system. Consisting of a mass-spring-damper such that the stiffness is essentially nonlinear, a NES can localize vibrational energy from a source and dissipate it through damping. Replacing the NES mass with a series of magnets surrounded by coils fixed to the primary mass, the dissipated energy can be directly converted to electrical energy. A NES with energy harvesting properties is constructed and introduced. The system parameters are identified, with the NES having an essentially cubic nonlinear stiffness. A transduction factor is quantified linking the electrical and mechanical systems. An analytic analysis is carried out studying the transient and harmonically excited response of the system. It is found that the energy harvesting does not reduce the vibrational absorption capabilities of the NES. The performance of the system in both transient and harmonically excited responses is found to be heavily influenced by input energies. The system is tested, with good match to analytic results.

  18. Selective Harvesting of Marginating-pulmonary Leukocytes.

    PubMed

    Shaashua, Lee; Sorski, Liat; Melamed, Rivka; Ben-Eliyahu, Shamgar

    2016-01-01

    Marginating-pulmonary (MP) leukocytes are leukocytes that adhere to the inner endothelium of the lung capillaries. MP-leukocytes were shown to exhibit unique composition and characteristics compared to leukocytes of other immune compartments. Evidence suggests higher cytotoxicity of natural killer cells, and a distinct pro- and anti-inflammatory profile of the MP-leukocyte population compared to circulating or splenic immunocytes. The method presented herein enables selective harvesting of MP-leukocytes by forced perfusion of the lungs in either mice or rats. In contrast to other methods used to extract lung-leukocytes, such as tissue grinding and biological degradation, this method exclusively yields leukocytes from the lung capillaries, uncontaminated with parenchymal, interstitial, and broncho-alveolar cells. In addition, the perfusion technique better preserves the integrity and the physiological milieu of MP-leukocytes, without inducing physiological responses due to tissue processing. This unique MP leukocyte population is strategically located to identify and react towards abnormal circulating cells, as all circulating malignant cells and infected cells are detained while passing through the lung capillaries, physically interacting with endothelial cells and resident leukocytes,. Thus, selective harvesting of MP-leukocytes and their study under various conditions may advance our understanding of their biological and clinical significance, specifically with respect to controlling circulating aberrant cells and lung-related diseases. PMID:27023665

  19. Multiple cell configuration electromagnetic vibration energy harvester

    NASA Astrophysics Data System (ADS)

    Marin, Anthony; Bressers, Scott; Priya, Shashank

    2011-07-01

    This paper reports the design of an electromagnetic vibration energy harvester that doubles the magnitude of output power generated by the prior four-bar magnet configuration. This enhancement was achieved with minor increase in volume by 23% and mass by 30%. The new 'double cell' design utilizes an additional pair of magnets to create a secondary air gap, or cell, for a second coil to vibrate within. To further reduce the dimensions of the device, two coils were attached to one common cantilever beam. These unique features lead to improvements of 66% in output power per unit volume (power density) and 27% increase in output power per unit volume and mass (specific power density), from 0.1 to 0.17 mW cm-3 and 0.41 to 0.51 mW cm-3 kg-1 respectively. Using the ANSYS multiphysics analysis, it was determined that for the double cell harvester, adding one additional pair of magnets created a small magnetic gradient between air gaps of 0.001 T which is insignificant in terms of electromagnetic damping. An analytical model was developed to optimize the magnitude of transformation factor and magnetic field gradient within the gap.

  20. Fungi That Infect Cottonseeds Before Harvest

    PubMed Central

    Simpson, Marion E.; Marsh, Paul B.; Merola, George V.; Ferretti, Renato J.; Filsinger, Elizabeth C.

    1973-01-01

    As a part of an investigation of aflatoxins and other mycotoxins in cottonseeds at harvest, samples of seeds collected from the 1971 crop at locations across the U.S. Cotton Belt were examined to determine the kinds of microorganisms causing internal or seed-coat infection in the field. Aspergillus flavus infection was absent from all seeds examined from most areas but was present in some samples from Arizona, California, and Texas. Fusarium spp., Alternaria sp., and A. niger caused internal infection at many locations; Colletotrichum gossypii and Rhizopus stolonifer were present in seeds from some areas but were generally much less common. Many of the infections with A. niger were in the seed coat. Bacterial infections were fairly frequent. In a series of commerical samples from Arizona. A. flavus infection was found in 61% of seeds, with fiber showing the bright, greenish-yellow (BGY) fluorescence that is diagnostic for A. flavus boll rot. Aflatoxin contamination was also concentration in the same seeds. The above findings agree with previous data showing that aflatoxin contamination of cottonseeds before harvest occurs rarely, if at all, in most parts of the U.S. Cotton Belt and that when such contamination does occur, it tends to be concentrated in seeds with the BGY fluorescence in their fiber and seed fuzz. PMID:16349975

  1. Parametrization of ambient energy harvesters for complementary balanced electronic applications

    NASA Astrophysics Data System (ADS)

    Verbelen, Yannick; Braeken, An; Touhafi, Abdellah

    2013-05-01

    The specific technical challenges associated with the design of an ambient energy powered electronic system currently requires thorough knowledge of the environment of deployment, energy harvester characteristics and power path management. In this work, a novel flexible model for ambient energy harvesters is presented that allows decoupling of the harvester's physical principles and electrical behavior using a three dimensional function. The model can be adapted to all existing harvesters, resulting in a design methodology for generic ambient energy powered systems using the presented model. Concrete examples are included to demonstrate the versatility of the presented design in the development of electronic appliances on system level.

  2. Effect of garment design on piezoelectricity harvesting from joint movement

    NASA Astrophysics Data System (ADS)

    Yang, Jin-Hee; Cho, Hyun-Seung; Park, Seon-Hyung; Song, Seung-Hwan; Yun, Kwang-Seok; Lee, Joo Hyeon

    2016-03-01

    The harvesting of piezoelectricity through the human body involves the conversion of mechanical energy, mostly generated by the repeated movements of the body, to electrical energy, irrespective of the time and location. In this research, it was expected that the garment design would play an important role in increasing the efficiency of piezoelectricity scavenged in a garment because the mechanical deformation imposed on the energy harvester could increase through an optimal design configuration for the garment parts supporting a piezoelectricity harvester. With this expectation, this research aimed to analyze the effect of the clothing factors, and that of human factors on the efficiency of piezoelectricity harvesting through clothing in joint movements. These analyses resulted in that the efficiency of the piezoelectricity harvesting was affected from both two clothing factors, tightness level depending upon the property of the textile material and design configuration of the garment part supporting the piezoelectricity harvesting. Among the three proposed designs of the garment part supporting the piezoelectricity harvesting, ‘reinforced 3D module design,’ which maximized the value of radius in the piezoelectricity harvester, showed the highest efficiency across all areas of the joints in the human body. The two human factors, frequency of movement and body part, affected the efficiency of the piezoelectricity harvesting as well.

  3. A piezoelectric bistable plate for nonlinear broadband energy harvesting

    NASA Astrophysics Data System (ADS)

    Arrieta, A. F.; Hagedorn, P.; Erturk, A.; Inman, D. J.

    2010-09-01

    Recently, the idea of using nonlinearity to enhance the performance of vibration-based energy harvesters has been investigated. Nonlinear energy harvesting devices have been shown to be capable of operating over wider frequency ranges delivering more power than their linear counterparts, rendering them more suitable for real applications. In this paper, we propose to exploit the rich nonlinear behavior of a bistable composite plate with bonded piezoelectric patches for broadband nonlinear energy harvesting. The response of the structure is experimentally investigated revealing different large amplitude oscillations. Substantially large power is extracted over a wide frequency range achieving broadband nonlinear energy harvesting.

  4. Piezoelectric energy harvesting: State-of-the-art and challenges

    NASA Astrophysics Data System (ADS)

    Toprak, Alperen; Tigli, Onur

    2014-09-01

    Piezoelectric energy harvesting has attracted wide attention from researchers especially in the last decade due to its advantages such as high power density, architectural simplicity, and scalability. As a result, the number of studies on piezoelectric energy harvesting published in the last 5 years is more than twice the sum of publications on its electromagnetic and electrostatic counterparts. This paper presents a comprehensive review on the history and current state-of-the art of piezoelectric energy harvesting. A brief theory section presents the basic principles of piezoelectric energy conversion and introduces the most commonly used mechanical architectures. The theory section is followed by a literature survey on piezoelectric energy harvesters, which are classified into three groups: (i) macro- and mesoscale, (ii) MEMS scale, and (iii) nanoscale. The size of a piezoelectric energy harvester affects a variety of parameters such as its weight, fabrication method, achievable power output level, and potential application areas. Consequently, size-based classification provides a reliable and effective basis to study various piezoelectric energy harvesters. The literature survey on each scale group is concluded with a summary, potential application areas, and future directions. In a separate section, the most prominent challenges in piezoelectric energy harvesting and the studies focusing on these challenges are discussed. The conclusion part summarizes the current standing of piezoelectric energy harvesters as possible candidates for various applications and discusses the issues that need to be addressed for realization of practical piezoelectric energy harvesting devices.

  5. Vibration energy harvesting from random force and motion excitations

    NASA Astrophysics Data System (ADS)

    Tang, Xiudong; Zuo, Lei

    2012-07-01

    A vibration energy harvester is typically composed of a spring-mass system with an electromagnetic or piezoelectric transducer connected in parallel with a spring. This configuration has been well studied and optimized for harmonic vibration sources. Recently, a dual-mass harvester, where two masses are connected in series by the energy transducer and a spring, has been proposed. The dual-mass vibration energy harvester is proved to be able to harvest more power and has a broader bandwidth than the single-mass configuration, when the parameters are optimized and the excitation is harmonic. In fact, some dual-mass vibration energy harvesters, such as regenerative vehicle suspensions and buildings with regenerative tuned mass dampers (TMDs), are subjected to random excitations. This paper is to investigate the dual-mass and single-mass vibration harvesters under random excitations using spectrum integration and the residue theorem. The output powers for these two types of vibration energy harvesters, when subjected to different random excitations, namely force, displacement, velocity and acceleration, are obtained analytically with closed-form expressions. It is also very interesting to find that the output power of the vibration energy harvesters under random excitations depends on only a few parameters in very simple and elegant forms. This paper also draws some important conclusions on regenerative vehicle suspensions and buildings with regenerative TMDs, which can be modeled as dual-mass vibration energy harvesters. It is found that, under white-noise random velocity excitation from road irregularity, the harvesting power from vehicle suspensions is proportional to the tire stiffness and road vertical excitation spectrum only. It is independent of the chassis mass, tire-wheel mass, suspension stiffness and damping coefficient. Under random wind force excitation, the power harvested from buildings with regenerative TMD will depends on the building mass only, not

  6. Protocol and practice in the adaptive management of waterfowl harvests

    USGS Publications Warehouse

    Johnson, F.; Williams, K.

    1999-01-01

    Waterfowl harvest management in North America, for all its success, historically has had several shortcomings, including a lack of well-defined objectives, a failure to account for uncertain management outcomes, and inefficient use of harvest regulations to understand the effects of management. To address these and other concerns, the U.S. Fish and Wildlife Service began implementation of adaptive harvest management in 1995. Harvest policies are now developed using a Markov decision process in which there is an explicit accounting for uncontrolled environmental variation, partial controllability of harvest, and structural uncertainty in waterfowl population dynamics. Current policies are passively adaptive, in the sense that any reduction in structural uncertainty is an unplanned by-product of the regulatory process. A generalization of the Markov decision process permits the calculation of optimal actively adaptive policies, but it is not yet clear how state-specific harvest actions differ between passive and active approaches. The Markov decision process also provides managers the ability to explore optimal levels of aggregation or "management scale" for regulating harvests in a system that exhibits high temporal, spatial, and organizational variability. Progress in institutionalizing adaptive harvest management has been remarkable, but some managers still perceive the process as a panacea, while failing to appreciate the challenges presented by this more explicit and methodical approach to harvest regulation. Technical hurdles include the need to develop better linkages between population processes and the dynamics of landscapes, and to model the dynamics of structural uncertainty in a more comprehensive fashion. From an institutional perspective, agreement on how to value and allocate harvests continues to be elusive, and there is some evidence that waterfowl managers have overestimated the importance of achievement-oriented factors in setting hunting

  7. Magnetic microparticles for harvesting Dunaliella tertiolecta microalgae

    NASA Astrophysics Data System (ADS)

    Manousakis, Emmanouil; Manariotis, Ioannis D.

    2016-04-01

    Microalgae based biofuels have been considered as a sustainable alternative to traditional fuels due to the higher biomass yield and lipid productivity, and the ability to be cultivated in non arable land making them not antagonistic with food supply chain. Due to the dilute nature of algal cultures and the small size of algae cells, the cost of microalgae harvesting is so far a bottleneck in microalgal based biofuel production. It is estimated that the algal recovery cost is at least 20-30% of the total biomass production cost. Various processes have been employed for the recovery of microalgal biomass, which include centrifugation, gravity separation, filtration, flocculation, and flotation. Recently, magnetophoric harvesting has received increased attention for algal separation, although it has been first applied for algal removal since the mid of 1970s. The magnetic separation process is based on bringing in contact the algal cells with the magnetic particles, and separating them from the liquid by an external magnetic force. The aim of this work was to investigate the harvesting of microalgae cells using Fe3O4 magnetic microparticles (MPs). Dunaliella tertiolecta was selected as a representative for marine microalgae. D. tertiolecta was cultivated under continuous artificial light, in 20 L flasks. Fe3O4 MPs were prepared by microwave irradiation of FeSO4 7H2O in an alkaline solution. Numerous batch and flow-through experiments were conducted in order to investigate the effect of the magnetic material addition on microalgae removal. Batch experiments were conducted examining different initial algal and MPs concentration, and algal culture volume. Flow-through experiments were conducted in a laboratory scale column made of Plexiglass. External magnetic field was applied by arranging at various points across the column length NdFeB magnets. Algal removal in flow-through experiments ranged from 70 to 85% depending on the initial MPs concentration and the hydraulic

  8. Harvesting dissipated energy with a mesoscopic ratchet.

    PubMed

    Roche, B; Roulleau, P; Jullien, T; Jompol, Y; Farrer, I; Ritchie, D A; Glattli, D C

    2015-01-01

    The search for new efficient thermoelectric devices converting waste heat into electrical energy is of major importance. The physics of mesoscopic electronic transport offers the possibility to develop a new generation of nanoengines with high efficiency. Here we describe an all-electrical heat engine harvesting and converting dissipated power into an electrical current. Two capacitively coupled mesoscopic conductors realized in a two-dimensional conductor form the hot source and the cold converter of our device. In the former, controlled Joule heating generated by a voltage-biased quantum point contact results in thermal voltage fluctuations. By capacitive coupling the latter creates electric potential fluctuations in a cold chaotic cavity connected to external leads by two quantum point contacts. For unequal quantum point contact transmissions, a net electrical current is observed proportional to the heat produced. PMID:25828578

  9. PS2004 Light-harvesting Systems Workshop

    SciTech Connect

    Robert E. Blankenship

    2005-11-01

    This special issue of the international scientific research journal Photosynthesis Research consists of 25 original peer-reviewed contributions from participants in the PS 2004 Lisht-Harvesting Systems Workshop. This workshop was held from 26-29, 2004 at Hotel Le Chantecler, Sainte-Adele, Quebec, Canada. The workshop was a satellite meeting of the XIII International Congress on Photosynthesis held August 29-September 3, 2004 in Montreal, Canada. The workshope dealt with all types of photosynthetic antenna systems and types of organisms, including anoxygenic photosynthetic bacteria, cyanobacteria, algae and higher plants, as well as in vitro studies of isolated pigments. This collection of papers is a good representation of the highly interdisciplinary nature of modern research on photosynthetic antenna complexes, utilizing techniques of advanced spectroscopy, biochemistry, molecular biology, synthetic chemistry and structural determination to understand these diverse and elegant molecular complexes.

  10. Nonlinear modeling of MEMS piezoelectric energy harvesters

    NASA Astrophysics Data System (ADS)

    Wang, Y. C.; Huang, T. W.; Shu, Y. C.; Lin, S. C.; Wu, W. J.

    2016-04-01

    This article presents the modeling of nonlinear response of micro piezoelectric energy harvesters under amplified base excitation. The micro transducer is a composite cantilever beam made of the PZT thick film deposited on the stainless-steel substrate. The model is developed based on the Euler-Bernoulli beam theory considering geometric and inertia nonlinearities, and the reduced formulation is derived based on the Hamiltonian variational principle. The harmonic balance method is used to simulate the nonlinear frequency response under various magnitudes of excitation and electric loads. The hardening type of nonlinearity is predicted and is found to be in good agreement with experiment. However, the softening response is also observed in different samples fabricated under different conditions. Such disagreement is under investigation.