Journal articles on the topic 'Harvesters'
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Yarborouph, David E. "A COMPARISON OF THREE MECHANICAL HARVESTERS AND HANDRAKING FOR WILD BLUEBERRIES." HortScience 27, no. 6 (June 1992): 600d—600. http://dx.doi.org/10.21273/hortsci.27.6.600d.
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Hand raking was compared to a non-mechanized machine and to two self propelled harvesters for yield and harvest time. Experimental design was split-plot replicated six times with four harvesters/plot with each raker using each machine in each plot. The machines were operated adjacent to one another. Hand raking resulted in the highest yield recovery of all harvesters. Average yield varied by raker from a high of 4831 kg/ha to a low of 3884 kg/ha. The Bluevester harvester recovered 91% of hand harvest and was 1.6 times faster than hand raking while the Darlington machine harvested one half of hand harvest in one quarter of the time. The Easy Pick recovered 81% of hand harvest but was twice as fast. Mechanical harvesters took less time but recovered fewer berries. A economic analysis is needed to fully evaluate these machines.
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Astafyev, V. L., and E. V. Zhalnin. "Efficiency Evaluation of Grain Harvesters of Different Types under North Kazakhstan Conditions." Agricultural Machinery and Technologies 12, no. 3 (July 26, 2018): 17–21. http://dx.doi.org/10.22314/2073-7599-2018-12-3-17-21.
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The problem of selecting certain types of grain combine harvesters is quite urgent now. This is because the agricultural manufacturers are struggling to make a right selection of a grain harvester of a definite firm or make due to the aggressive marketing from the manufacturers. (Research purpose) Efficiency evaluation of grain harvesters of different types under the North Kazakhstan weather conditions. (Materials and methods) Technical and economic research has been performed according to the standard methodology followed by data analysis. The calculation has been made for direct combining by 4, 5 and 6-class harvesters equipped with widecut headers from leading domestic and foreign manufacturers. (Results and discussions) the authors have also calculated direct costs for thrashing of one ton of grain under favorable harvesting conditions, total costs for thrashing of one ton of grain including grain losses under unfavorable harvesting conditions, as well as total costs for thrashing of one ton of grain considering that 30% of grain is harvested under favorable harvesting conditions and 70% - under the ones. (Conclusion) It has been found that the price of thrashing of one ton of grain that characterizes the efficiency of utilizing grain harvesters depends on the price/efficiency ratio of a harvester, yield and harvesting conditions. Combine harvesters of a lower class with the optimum price/efficiency ratio are more preferable under favorable harvesting conditions. However, in case of the harvest period prolongation due to unfavorable harvesting conditions, combine harvesters of a higher class are more preferable.
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Malaji, P. V., Suresh Doddi, Michael I. Friswell, and Sondipon Adhikari. "Analysis of pendulums coupled by torsional springs for energy harvesting." MATEC Web of Conferences 211 (2018): 05008. http://dx.doi.org/10.1051/matecconf/201821105008.
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Harvesting energy from ambient sources has been a recent topic of interest. A typical linear harvester is effective only near resonance, limiting its frequency bandwidth. In order to increase the efficiency and bandwidth of harvesters, various strategies have been proposed. Using multiple harvesters in a single device can harvest enough power over wider frequency band. In the present work, the effect of torsional coupling of the harvesters for low frequency vibration energy harvesting is investigated. Two pendulums with electromagnetic induction as the energy conversion mechanism is proposed. The performance of the device is studied theoretically and numerically. Cubic polynomials are used to model the pendulum nonlinearity. Fundamental harmonic oscillation are assumed to obtain the analytical solution. The effect of torsional coupling and pendulum length on the power harvested are reported.
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Novák, Pavel, and Patrik Burg. "Evaluation of harvest losses within a full mechanised grape harvest." Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 61, no. 3 (2013): 751–56. http://dx.doi.org/10.11118/actaun201361030751.
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A contribution deals with an evaluation of harvest losses within a full mechanised berries harvest using two self-propelled harvesters GREGOIRE G 152 and NEW HOLLAND VL 6060 differing in kinds of harvesting and catching mechanisms. Observation was done in vineyards of ZVOS Hustopeče joint–stock company at harvest of Müller Thurgau and Lemberger varieties in a period 2009–2010. Results gained under operating conditions showed that both self-propelled harvesters reached a comparable quality of a harvested product. There were observed losses by a slump in a case of using GREGOIRE G 152 harvester 0.8–1.45%. By using NEW HOLLAND VL 6060 the losses were 0.86–1.52% and data were gained with a respect to vine condition, the variety and the vintage. Next to losses by the slump also losses as non-harvested product were observed. Using GREGOIRE G 152 were reached 1.08–2.56% of non-harvested product losses and in a case of NEW HOLLAND VL 6060 similarly 1.17–2.22%. However a value of the non-harvested product losses cannot be perceived absolutely because in a practice the non-harvested grapes are consequently picked up manually. Total losses perceived as a sum of losses by the slump and non-harvested losses values were at GREGOIRE G 152 harvester 2–4% and at NEW HOLLAND VL 6060 harvester 2–3.7% of total hectare yield.
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Yarborough, David E. "A Reevaluation of Mechanical Harvester vs. Hand-raking for Wild Blueberries." HortScience 30, no. 4 (July 1995): 800F—800. http://dx.doi.org/10.21273/hortsci.30.4.800f.
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Improvements in the Bragg harvester and the introduction of a new Nimco harvester warranted a reevaluation of new technologies. Four technologies: the Bragg harvester, a modified Bragg harvester, the Nimco prototype, and hand-harvesting were evaluated at two locations: a land-leveled field (T-19) and a field without land leveling (Deblois). The experimental design was a randomized complete block with eight replications. A 150-ft strip was harvested with each technology, with strips directly adjacent to each other to minimize field variability. Time to harvest and berry weights were measured. Poor maintenance, adjustment and skill of the operator contributed to a 69% recovery relative to hand-harvest by both the Bragg and modified Bragg harvesters. The Nimco harvester has great potential, but only if it is properly mounted to allow it to cover the fields at a speed similar to the Bragg harvesters. The land-leveled field allowed for greater recovery for the Bragg and Nimco harvester, indicating that smoother fields are more efficient for machine-harvesting.
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Shan, Xiaobiao, Haigang Tian, Han Cao, Ju Feng, and Tao Xie. "Experimental Investigation on a Novel Airfoil-Based Piezoelectric Energy Harvester for Aeroelastic Vibration." Micromachines 11, no. 8 (July 26, 2020): 725. http://dx.doi.org/10.3390/mi11080725.
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This paper presents a novel airfoil-based piezoelectric energy harvester (EH) with two small square prisms attached to an airfoil. This harvester can achieve a two degree-of-freedom (DOF) plunge–pitch motions. Several prototypes of energy harvester were fabricated to explore the nonlinear aerodynamic response and the output performance in a wind tunnel. The experimental results showed that the longer the flexible spring was, the lower the critical velocity and frequency of the harvester were, and the better aerodynamic response and output performance could be achieved. The initial disturbance, the following limit-cycle oscillation, and the ultimate chaos of nonlinear response occurred, as increasing airflow velocity was increased. The overall output performance of the harvesters with a flexible spring having a thickness of 1 mm outperformed than that of the harvesters with a flexible spring having a thickness of 0.5 mm at a higher airflow velocity, while the tendency was opposite at a lower velocity. An optimum output voltage of 17.48 V and a power of 0.764 mW were harvested for EH-160-1 at 16.32 m/s, which demonstrated it possessed better performance than the other harvesters. When the capacitor was charged for 45 s and directly drove a sensor, it could maintain working for 17 s to display temperature and humidity in real time.
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Pajic, Milos, Vesna Pajic, Sanjin Ivanovic, Mico Oljaca, Kosta Gligorevic, Dusan Radojicic, Milan Drazic, and Ivan Zlatanovic. "Influence of harvester type and harvesting time on quality of harvested chamomile." Journal of Agricultural Sciences, Belgrade 61, no. 2 (2016): 201–13. http://dx.doi.org/10.2298/jas1602201p.
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This paper is the result of studying effects of mechanical chamomile harvesting on yield and quality of harvested chamomile. Chamomile (Chamomilla recutita (L) Rausch.) was harvested at three time intervals (T1 - 240 days, T2 - 250 days and T3 - 260 days after sowing) by three conceptually different harvesters. The results achieved indicate that the harvester type significantly influences quality of harvested chamomile, whereas it is not influenced by chamomile harvesting time. Quality of harvested chamomile was classified into four categories, and it was observed that the greater number of rotations of a picking device increased the content of the first category of quality. The harvester A achieved 54.79% of the first category of quality in respect to the harvester B achieving 50.26% and the harvester C with 42.93%.
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Sirén, Matti, and Hannu Aaltio. "Productivity and Costs of Thinning Harvesters and Harvester-Forwarders." International Journal of Forest Engineering 14, no. 1 (January 2003): 39–48. http://dx.doi.org/10.1080/14942119.2003.10702468.
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Masoumi, Hamidreza, Hamid Moeenfard, Hamed Haddad Khodaparast, and Michael I. Friswell. "On the Effects of Structural Coupling on Piezoelectric Energy Harvesting Systems Subject to Random Base Excitation." Aerospace 7, no. 7 (July 4, 2020): 93. http://dx.doi.org/10.3390/aerospace7070093.
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The current research investigates the novel approach of coupling separate energy harvesters in order to scavenge more power from a stochastic point of view. To this end, a multi-body system composed of two cantilever harvesters with two identical piezoelectric patches is considered. The beams are interconnected through a linear spring. Assuming a stochastic band limited white noise excitation of the base, the statistical properties of the mechanical response and those of the generated voltages are derived in closed form. Moreover, analytical models are derived for the expected value of the total harvested energy. In order to maximize the expected generated power, an optimization is performed to determine the optimum physical and geometrical characteristics of the system. It is observed that by properly tuning the harvester parameters, the energy harvesting performance of the structure is remarkably improved. Furthermore, using an optimized energy harvester model, this study shows that the coupling of the beams negatively affects the scavenged power, contrary to the effect previously demonstrated for harvesters under harmonic excitation. The qualitative and quantitative knowledge resulting from this analysis can be effectively employed for the realistic design and modelling of coupled multi-body structures under stochastic excitations.
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Machado, Túlio de A., Haroldo C. Fernandes, Clarice A. Megguer, Nerilson T. Santos, and Fabio L. Santos. "Quantitative and qualitative loss of tomato fruits during mechanized harvest." Revista Brasileira de Engenharia Agrícola e Ambiental 22, no. 11 (November 2018): 799–803. http://dx.doi.org/10.1590/1807-1929/agriambi.v22n11p799-803.
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ABSTRACT The use of mechanization in the harvesting of industrial tomatoes provides greater yield and speed of this stage. However, mechanical intervention in this process may alter the physiology of harvested fruits. Therefore, the objective of this study was to measure the quantitative losses of tomato fruits and to verify the physico-chemical behavior of fruits harvested based on physicochemical analysis in harvesters with different hours of use. Three self-propelled harvesters of the same brand and model with different working hours were used. Manually selected or undamaged fruits were harvested; afterwards, mechanized harvesting was carried out. Firmness, titratable acidity, soluble solids content (°Brix), pH, weight loss and fruit status classification proposed by the Ministry of Livestock, Agriculture and Food Supply of 2002 were evaluated. Quantitative losses were divided into: losses on vines, losses on soil and total losses. It was found that the number of hours worked by the harvester did not affect the quantitative losses. The amount of overall damage in a certain amount of fruit is greater when the harvester has a greater number of hours worked. Mechanized harvesting affected the physical attributes of the fruits, such as firmness and percentage of weight loss.
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Kim, Sung-Eun, Taewook Kang, Kwang-Il Oh, Mi Park, Hyung-Il Park, In Lim, and Jae-Jin Lee. "Energy Management Integrated Circuit for Multi-Source Energy Harvesters in WBAN Applications." Applied Sciences 8, no. 8 (July 31, 2018): 1262. http://dx.doi.org/10.3390/app8081262.
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This paper presents an energy management integrated circuit for multiple energy harvesters in wireless body area network applications. The electrical power acquired from a single energy harvester around a human body is limited to micro watts, which is insufficient to drive a wearable electronic device. To increase this small amount, the energy from a number of harvesters has to be combined. By combining the energy from multiple distributed harvesters, each one producing negligible energy, significant energy for wearable devices can be obtained. In designing an energy management circuit for a wearable device, there are two issues to be resolved. The first is related to the power consumption of the circuit, and the second issue is related to the methods needed to manage the wide range of power that occurs as the energy input changes during harvesting. In this paper, an energy management circuit that resolves the two issues above is described. The circuit was integrated using 0.13 µm Taiwan Semiconductor Manufacturing Company complementary metal-oxide-semiconductor technology. The energy management circuit is designed to combine up to three sources of harvested energy with more than 90% operating efficiency over the entire power range of the energy harvested.
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Hossain, MA, MA Hoque, MA Wohab, MA M. Miah, and MS Hassan. "Technical and economic performance of combined harvester in farmers field." Bangladesh Journal of Agricultural Research 40, no. 2 (August 20, 2015): 291–304. http://dx.doi.org/10.3329/bjar.v40i2.24569.
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Labour scarcity, harvesting loss, timely harvesting and harvesting cost are crucial in rice and wheat harvesting in Bangladesh. Combine harvester is a newly introduced harvesting machine in Bangladesh. This study was undertaken to evaluate the technical and economic performance of combine harvester available in farmers? field and farmer?s perception regarding the use of combine. Field tests of two new (CLASS andDaedong) and two refresh (Kukje and Anower) combine harvesters were conducted for harvesting rice and wheat in the farners? field of Jessore, Pabna,Dinajpurand Thakurgaon districts during 2011-12. Primary data were collected from 30 adopter and 30 non-adopter farmers from each district of Bogra, Rangpur, Dinajpur and Thakurgaon through direct interviewingduring 2012-13. Information was also collected from different combine harvester traders available in Bangladesh. Average time, cost and grain saving by combine harvester over manual methods were 97.50, 35.00 and 2.75%, respectively. Benefit cost ratio of CLASS, Daedong, Kukje and Anower combine harvesters were found to be 2.68, 2.11, 2.29 and 2.70, respectively. The payback periods of refresh combine harvesters were lower than the new combine harvester. There were some mechanical problems observed in refresh combine harvesters during field operations. New harvester was observed almost trouble free and popular to the famers. Scarcity of spare parts and mechanic service were the main problems for repair and maintenance of the combine harvesters in farm level. Considering the technical performance of combine harvester and demand of the farmers, new combine harvester may be introduced in commercial basis in Bangladesh.Bangladesh J. Agril. Res. 40(2): 291-304 June 2015
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Hammad, Bashar, Hichem Abdelmoula, Eihab Abdel-Rahman, and Abdessattar Abdelkefi. "Nonlinear Analysis and Performance of Electret-Based Microcantilever Energy Harvesters." Energies 12, no. 22 (November 7, 2019): 4249. http://dx.doi.org/10.3390/en12224249.
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An energy harvester composed of a microcantilever beam with a tip mass and a fixed electrode covered with an electret layer is investigated when subject to an external harmonic base excitation. The tip mass and fixed electrode form a variable capacitor connected to a load resistance. A single-degree-of-freedom model, derived based on Newton’s and Kirshoff’s laws, shows that the tip mass displacement and charge in the variable capacitor are nonlinearly coupled. Analysis of the eigenvalue problem indicates the influence of the electret surface voltage and electrical load resistance on the harvester linear characteristics, namely the harvester coupled frequency and electromechanical damping. Then, the frequency–response curves are obtained numerically for a range of load resistance, electret voltage and base excitation amplitudes. A softening nonlinear effect is observed as a result of decreasing the load resistance and increasing the electret voltage. It is found that there is an optimal electret voltage with the highest harvested electrical power. Below this optimal value, the bandwidth is very small, whereas the bandwidth is large when the electret voltage is above this optimal value. In addition, it is noted that for a certain excitation frequency, the harvested power decreases or increases as a function of electrical load resistance when the coupled frequency is closer to short- or open-circuit frequency, respectively. However, when the coupled frequency is between the short-circuit and open-circuit frequencies, the harvested power has an optimal resistance with the highest power. Increasing the excitation amplitude to raise the harvested power could be accompanied with dynamic pull-in instability and/or softening behavior depending on the electrical load resistance and electret voltage. However, large softening behavior would prevent the pull-in instability, increase the level of the harvested power, and broaden the bandwidth. These observations give a deeper insight into the behavior of such energy harvesters and are of great importance to the designers of electrostatic energy harvesters.
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Tihanov, G. "A study on the hopper unloading duration of the harvesting machine at different technical parameters." Agricultural Science and Technology 12, no. 2 (June 2020): 140–43. http://dx.doi.org/10.15547/ast.2020.02.023.
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Abstract. When unloading grain harvester hoppers at standstill the time of emptying the hopper has a significant effect on the harvester productivity. The paper is about a conducted survey in 15 agricultural farms with 15 harvesters monitored including 14 models of 6 different brands during wheat harvesting. The time for emptying the grain hopper of the harvesters was defined by measuring the time. It was found that the actual time for emptying the hoppers of the studied harvesters was 134.85 s, and the actual flow rate of unloading of the screw in them being 69.63 L/s on average. A multivariate regression analysis was performed on the effect of the harvester grain hopper volume and the actual flow rate of the unloading screw on the time from switching on the unloading screw till its switching off in various grain harvesters. An adequate mathematical model of the effect of the hopper volume and the flow rate of the unloading screw of grain harvesters on the time for emptying the grain hopper under real production conditions has also been created. These results can also be used for minimizing costs in the technological process at harvesting.
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Piskunov, M. A. "Research on the price of harvesters in the secondary market as an aspect of changing their technical condition." Traktory i sel'hozmashiny 1, no. 5 (2020): 37–44. http://dx.doi.org/10.31992/0321-4443-2020-5-37-44.
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In the timber industry complex of Russia, medium-sized and small enterprises with a volume of timber harvesting up to 100 thousand cubic meters per year occupy a share of 48% in the total vol-ume. Most of these enterprises do not have the capacity to purchase new harvesters. An alternative to the new harvesters are the harvesters from the secondary market. Thus the study of changes in the technical condition of harvesters during their operation is an actual study for Russia. The data on the models, age, number of hours worked and the cost of harvesters that are offered on the secondary market was collected. 202 commercial offers were collected. In total there are 31 harvesters under 5 years of operation; 99 harvesters from 5 to 10 years of operation; 56 – from 10 to 15 years of operation; and 16 – older than 15 years of operation. There are 73 John Deere harvesters (including the outdated Timberjack models), with 8 tracked vehicles, 29 Ponsse harvesters; 49 Komatsu harvesters (including the out-dated Valmet models) with 4 harvesters based on a tracked excavator; 37 harvesters of different models made on the basis of tracked excavators and 18 harvesters of other models. Hypothetically assuming that there is a connection between the price of the harvester and its condition, correlations were analyzed between the price and the age of the harvester and between the price and the number of worked hours of the harvester. The relationship between the price and the age is described by power and exponential curves, with coefficients of determination of 0.56 and 0.54, respectively. Filtering data by power range (160-205 kW) and by model (three models were considered: John Deere 1270; Ponsse Ergo; Komatsu 931) did not lead to clear certainty about the form of regression, although it slightly increased the coefficient of determination. There are groups of factors that can influence the type of regression: the seller's factor, the repair factor, the operation factor, and the technical characteristics factor, but determining the degree of influence of these groups requires additional research. The dependence between the price and the number of worked hours is characterized by a very weak relation due to a large spread of data owing to incorrect values of the hours marked by sellers. General regression trends for harvesters are consistent with data for other types of tractors. But to determine unambiguity in regressions requires the accumulation of empirical data on the reliability of machinery and changes in their price over a number of years.
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Abdelkefi, Abdessattar, Muhammad R. Hajj, and Ali H. Nayfeh. "Sensitivity analysis of piezoaeroelastic energy harvesters." Journal of Intelligent Material Systems and Structures 23, no. 13 (March 26, 2012): 1523–31. http://dx.doi.org/10.1177/1045389x12440752.
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We perform a sensitivity analysis of a piezoaeroelastic energy harvester consisting of a pitching and plunging rigid airfoil supported by flexural and torsional springs with a piezoelectric coupling attached to the plunge degree of freedom. We employ the nonintrusive formulation of the polynomial chaos expansion in terms of the multivariate Hermite polynomials to quantify the effects of variations in the load resistance, the eccentricity (distance between the center of mass and the elastic axis), and the nonlinear coefficients of the springs on the harvested power and the pitch and plunge amplitudes. As a first step, the normal form of the dynamics of the system near the Hopf bifurcation is used to select parameters that ensure a supercritical instability and maximize the generated power. The results show that the harvested power can be mostly affected by the eccentricity. Moreover, decreasing the nonlinear coefficient of the torsional spring results in a decrease in the pitch amplitude and an increase in the plunge amplitude and hence the harvested power. These results give guidance for optimizing and assessing the uncertainty in the performance of piezoaeroelastic energy harvesters.
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Raju, S. Srinivasulu, M. Umapathy, and G. Uma. "High-output piezoelectric energy harvester using tapered beam with cavity." Journal of Intelligent Material Systems and Structures 29, no. 5 (July 26, 2017): 800–815. http://dx.doi.org/10.1177/1045389x17721044.
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Energy harvesting using cantilever-based piezoelectric structure is most popular for harvesting electrical energy from ambient vibrations. Efforts are also made to maximize the harvester power by means of tailoring the structural parameters of the cantilever beam. This article proposes a method to maximize the harvester voltage from the cantilever-based piezoelectric energy harvester by means of tailoring the structure of the cantilever, to have a tapering in width, thickness and in both width and thickness (double taper). It is also proposed to introduce rectangular and trapezoidal cavities in the tapered energy harvesters to further maximize the harvester voltage. The analytical model of the proposed harvesters is developed using Euler–Bernoulli beam theory, and its free vibration solution is analysed using Bessel functions. The energy harvesters are fabricated and experimentally evaluated for its performance. It is concluded from the results of analytical model and experimentation that width, thickness and double-tapered beam increases the harvester voltage by 35.6%, 84.8% and 126.6%, respectively, as compared to the energy harvester designed with uniform cantilever beam. Among all the energy harvesters proposed in this article, the maximum voltage is generated from the double-tapered beam with trapezoidal cavity. The experimental results are in close agreement with the results obtained from the analytical model.
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Bhaskaran, Prathish Raaja, Joseph Daniel Rathnam, Sumangala Koilmani, and Kavitha Subramanian. "Multiresonant Frequency Piezoelectric Energy Harvesters Integrated with High Sensitivity Piezoelectric Accelerometer for Bridge Health Monitoring Applications." Smart Materials Research 2017 (January 29, 2017): 1–23. http://dx.doi.org/10.1155/2017/6084309.
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Wireless Structural Health Monitoring (WSHM) is a less expensive but efficient mode of health monitoring. However, it needs frequent change of batteries since remote WSHM consumes large power. The best scientific solution to this problem is to employ energy harvesters integrated along with the vibration sensors in the same substrate so that the battery is recharged by the energy harvested during vibrations caused by the passing vehicles in bridges. In this work, an attempt has been made to design an energy harvester and a micro accelerometer integrated chip. Civil structures have low natural frequencies and therefore low bandwidth design is adopted to maximize the harvested energy and accelerometer sensitivity. The other special feature of the proposed design is its ability to provide further increase in energy harvesting by the parallel operation of an array of energy harvesters with closely spaced natural frequencies. The studies show that the natural frequencies of the harvesters should be less than that of the structure in healthy condition. Simulation studies conducted on these devices show that it is possible to harvest a maximum power of 2.283 mW/g. The integrated micro accelerometer is also capable of giving a sensitivity of 27.67 V/g with appreciable improvement in other performance indices.
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AMATO, IVAN. "FOG HARVESTERS." Chemical & Engineering News 84, no. 20 (May 15, 2006): 13. http://dx.doi.org/10.1021/cen-v084n020.p013.
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Davis, Anthony, John Mark Hanson, Hadley Watts, and Holli MacPherson. "Local ecological knowledge and marine fisheries research: the case of white hake (Urophycis tenuis) predation on juvenile American lobster (Homarus americanus)." Canadian Journal of Fisheries and Aquatic Sciences 61, no. 7 (July 1, 2004): 1191–201. http://dx.doi.org/10.1139/f04-070.
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Southern Gulf of St. Lawrence fish harvesters voiced the concern that white hake (Urophycis tenuis) were jeopardizing the recruitment of juvenile American lobster (Homarus americanus), through predation, into the commercially exploitable population. The harvesters insisted that marine science was not documenting this situation, since sampling was being conducted in the wrong places and at the wrong times of year. This paper reports on the results arising from a 2-year collaborative and interdisciplinary research project designed to examine fish harvesters' concerns. Several social research methodologies were used to identify and interview local knowledge experts about where and when sampling should occur. Following harvesters' advice, white hake stomachs were sampled over a 2-year period. Contrary to harvester expectations, American lobster was not found in any of the 3080 white hake stomachs sampled. Yet, harvesters' advice did result in successful sampling from within the places recommended and at the times of year specified. The research also demonstrates an interdisciplinary and collaborative approach that generates meaningful research results while incorporating marine harvester local knowledge and addressing their concerns.
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Hasan, Md Kamrul, Takashi S. T. Tanaka, Md Rostom Ali, Chayan Kumer Saha, and Md Monjurul Alam. "Harvester Evaluation Using Real-Time Kinematic GNSS and Hiring Service Model." AgriEngineering 3, no. 2 (June 6, 2021): 363–82. http://dx.doi.org/10.3390/agriengineering3020024.
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To reduce human drudgery and the risk of labor shortages in the Asian developing countries, the appropriate introduction of agricultural machinery, especially combine harvesters, is an urgent task. Custom hiring services (CHSs) are expected to contribute to making paddy harvesters prevalent in developing countries; however, the economic performance has been rarely quantified. The study was carried out to precisely evaluate the machine performance attributes of medium and large combine harvesters using the real-time kinematic (RTK) global navigation satellite system (GNSS) and to estimate the economic performance of CHSs of paddy harvesters in Japan, as a typical case of Asian countries. The financial profitability was evaluated by four major indicators: net present value, benefit–cost ratio, internal rate of return, and payback period. The financial indicators showed that both types of harvester could be considered financially viable. Thus, the investment in combine harvesters can be highly profitable for CHS business by a local service provider and custom-hire entrepreneur, providing a great opportunity to use a combine harvester without initial investment by general farmers. The findings demonstrated the high feasibility of CHSs of paddy harvesters in Japan, while they highlighted that further study is needed to estimate the feasibility of CHS in the other Asian developing countries.
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Li, Changying, Pengcheng Yu, Fumiomi Takeda, and Gerard Krewer. "A Miniature Instrumented Sphere to Understand Impacts Created by Mechanical Blueberry Harvesters." HortTechnology 23, no. 4 (August 2013): 425–29. http://dx.doi.org/10.21273/horttech.23.4.425.
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The majority of U.S. northern highbush blueberry (Vaccinium corymbosum) and southern highbush blueberry (V. corymbosum hybrids) for the fresh market is hand harvested because of the high bruising damage to the fruit caused by current machine harvesters. To reduce bruising, it is important to understand how the harvester’s machine parts interact with the fruit. A miniature instrumented sphere, hereafter referred to as Smart Berry, was developed to mimic a blueberry (Vaccinium species and hybrids) fruit and to quantitatively measure mechanical impacts experienced by a real blueberry fruit during mechanical harvesting. The Smart Berry sensor recorded impacts using three single-axis accelerometers with a maximum sampling frequency of 3 kHz and ±500 gn sensing range. Calibration tests showed that the maximum error of the measurement was 0.53% of the output span. The diameter of the sensor (1 inch) was only half of that for the current smallest instrumented sphere on the market. Used together with a close-up video, the fully calibrated sensors were used to identify and measure mechanical impacts occurring in a commercial rotary blueberry harvester. The data suggested that the catch pan created the largest single mechanical impacts. Thus, reducing the drop height or padding the surface could be effective measures to reduce bruising damage caused by the catch pans. The Smart Berry was also used to compare harvesters with two different detaching mechanisms. The rotary detaching mechanism created significantly fewer and lower-magnitude impacts than the slapper mechanism (P ≤ 0.05). Manual drop tests demonstrated that the impact data recorded by the Smart Berry can be correlated with bruising damage experienced by blueberry fruit. Taken together, the data can be used to improve the design of the current machine harvesters for reduction of bruising damage to blueberry fruit destined for the fresh market, and potentially lead to enhanced highbush blueberry production efficiency in the long run.
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Zayed, Assal, Nakano, Kaizuka, and El-Bab. "Design Procedure and Experimental Verification of a Broadband Quad-Stable 2-DOF Vibration Energy Harvester." Sensors 19, no. 13 (June 29, 2019): 2893. http://dx.doi.org/10.3390/s19132893.
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Vibration-based energy harvesters brought the idea of self-powered sensors to reality in the past few years. Many strategies to improve the performance of linear vibration energy harvesters that collect energy over a limited bandwidth have been proposed. In this paper, a bi-stable two degrees of freedom (2-DOF) cut-out vibration energy harvester employing a pair of permanent magnets is designed through a proposed design methodology. Based on this methodology, the nonlinear harvesters can be optimally designed such that the bandwidth can be widened for a targeted output voltage. The proper selection of the harvester parameters as well as the gap distances between the tip and the fixed magnets are the bases of this methodology. The mathematical modeling of the proposed harvester and the formula for the potential energy between the tip and the fixed magnets are presented. Additionally, to enhance the performance of the bi-stable energy harvester (BEH), a quad-stable energy harvester (QEH) was configured by adding more fixed magnets. Experiments were performed to validate the numerical simulations and the results showed that, the simulation and experimental results are consistent. The results indicate that, the QEH covers a wider bandwidth than the BEH and based on a figure of merit the QEH shows the best performance among many harvesters presented in the literature.
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Frizzell, Ronan, Gerard Kelly, Francesco Cottone, Elisabetta Boco, Valeria Nico, Declan O’Donoghue, and Jeff Punch. "Experimental characterisation of dual-mass vibration energy harvesters employing velocity amplification." Journal of Intelligent Material Systems and Structures 27, no. 20 (July 28, 2016): 2810–26. http://dx.doi.org/10.1177/1045389x16642030.
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Vibration energy harvesting extracts energy from the environment and can mitigate reliance on battery technology in wireless sensor networks. This article presents the nonlinear responses of two multi-mass vibration energy harvesters that employ a velocity amplification effect. This amplification is achieved by momentum transfer from larger to smaller masses following impact between masses. Two systems are presented that show the evolution of multi-mass vibration energy harvester designs: (1) a simplified prototype that effectively demonstrates the basic principles of the approach and (2) an enhanced design that achieves higher power densities and a wider frequency response. Various configurations are investigated to better understand the nonlinear dynamics and how best to realise future velocity-amplified vibration energy harvesters. The frequency responses of the multi-mass harvesters show that these devices have the potential to reduce risks associated with deploying vibration energy harvester devices in wireless sensor network applications; the wide frequency response reduces the need to re-tune the harvesters following frequency variations of the source vibrations.
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Khan, Farid Ullah. "Energy Harvesting from the Stray Electromagnetic Field around the Electrical Power Cable for Smart Grid Applications." Scientific World Journal 2016 (2016): 1–20. http://dx.doi.org/10.1155/2016/3934289.
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For wireless sensor node (WSN) applications, this paper presents the harvesting of energy from the stray electromagnetic field around an electrical power line. Inductive and capacitive types of electrodynamic energy harvesters are developed and reported. For the produced energy harvesters, solid core and split-core designs are adopted. The inductive energy harvester comprises a copper wound coil which is produced on a mild steel core. However, the capacitive prototypes comprise parallel, annular discs separated by Teflon spacers. Moreover, for the inductive energy harvesters’ wound coil and core, the parametric analysis is also performed. A Teflon housing is incorporated to protect the energy harvester prototypes from the harsh environmental conditions. Among the inductive energy harvesters, prototype-5 has performed better than the other harvesters and produces a maximum rms voltage of 908 mV at the current level of 155 A in the power line. However, at the same current flow, the capacitive energy harvesters produce a maximum rms voltage of 180 mV. The alternating output of the prototype-5 is rectified, and a super capacitor (1 F, 5.5 V) and rechargeable battery (Nickel-Cadmium, 3.8 V) are charged with it. Moreover, with the utilization of a prototype-5, a self-powered wireless temperature sensing and monitoring system for an electrical transformer is also developed and successfully implemented.
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Morel, Adrien, Adrien Badel, Romain Grézaud, Pierre Gasnier, Ghislain Despesse, and Gaël Pillonnet. "Resistive and reactive loads’ influences on highly coupled piezoelectric generators for wideband vibrations energy harvesting." Journal of Intelligent Material Systems and Structures 30, no. 3 (November 18, 2018): 386–99. http://dx.doi.org/10.1177/1045389x18810802.
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One of the main challenges in energy harvesting from ambient vibrations is to find efficient ways to scavenge the energy, not only at the mechanical system resonance but also on a wider frequency band. Instead of tuning the mechanical part of the system, as usually proposed in the state of the art, this article develops extensively the possibility to tune the properties of the harvester using the electrical interface. Due to the progress in materials, piezoelectric harvesters can exhibit relatively high electromechanical coupling: hence, the electrical part can now have a substantial influence on the global parameters of the piezoelectric system. In order to harness the energy efficiently from this kind of generator on a wide frequency band, not only the electrical load’s effect on the harvester’s damping should be tuned but also its effect on the harvester’s stiffness. In this article, we present an analytical analysis of the influences of the resistive and reactive behavior of the electrical interface on highly coupled piezoelectric harvesters. We develop a normalized study of the multiphysics interactions, reducing the number of parameters of the problem to a few physically meaningful variables. The respective influence of each of these variables on the harvesting power has been studied and led us to the optimal electrical damping expression and the influences of the damping and of the coupling on the equivalent admittance of the piezoelectric energy harvester. Finally, we linked these normalized variables with real reactive load expressions, in order to study how a resistive, capacitive, and inductive behavior could affect the global performances of the system. The theoretical analysis and results are supported by experimental tests on a highly coupled piezoelectric system [Formula: see text]. Using an adequate tuning of a RC load at each frequency, the maximum harvested power [Formula: see text] under a small acceleration amplitude of [Formula: see text] is reached over a 14 Hz large frequency band around 105 Hz which has been predicted by the model with less than 5% error.
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Bryant, Matthew, Ranjeev L. Mahtani, and Ephrahim Garcia. "Wake synergies enhance performance in aeroelastic vibration energy harvesting." Journal of Intelligent Material Systems and Structures 23, no. 10 (May 6, 2012): 1131–41. http://dx.doi.org/10.1177/1045389x12443599.
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This study experimentally demonstrates that a closely spaced array of aeroelastic flutter energy harvesters can exploit synergistic wake interactions to outperform the same number of harvesters operating in isolation. The fluttering motion of each energy harvester imparts an oscillating vortex wake into the flow downstream of the device. Wind tunnel experiments with arrays of two and four flutter energy harvesters show that this wake structure has significant effects on the vibration amplitude, frequency, and power output of the trailing devices. These wake interaction effects are shown to vary with the stream-wise and cross-stream separation distance between the harvesters. Over a defined range of separations, an advantageous frequency lock-in between the devices arises. When this occurs, the trailing harvesters can extract additional energy from the wake of upstream harvesters, causing larger oscillation amplitudes and higher power output in the trailing devices. Experiments to characterize this variation in power output due to these wake interaction effects and to determine the optimal spacing of the energy harvesters are presented and discussed. Smoke-wire flow visualization is used to examine the wake structure and investigate the mechanism of the array interactions.
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Phan, Tra Nguyen, Sebastian Bader, and Bengt Oelmann. "Performance of An Electromagnetic Energy Harvester with Linear and Nonlinear Springs under Real Vibrations." Sensors 20, no. 19 (September 23, 2020): 5456. http://dx.doi.org/10.3390/s20195456.
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The introduction of nonlinearities into energy harvesting in order to improve the performance of linear harvesters has attracted a lot of research attention recently. The potential benefits of nonlinear harvesters have been evaluated under sinusoidal or random excitation. In this paper, the performances of electromagnetic energy harvesters with linear and nonlinear springs are investigated under real vibration data. Compared to previous studies, the parameters of linear and nonlinear harvesters used in this paper are more realistic and fair for comparison since they are extracted from existing devices and restricted to similar sizes and configurations. The simulation results showed that the nonlinear harvester did not generate higher power levels than its linear counterpart regardless of the excitation category. Additionally, the effects of nonlinearities were only available under a high level of acceleration. The paper also points out some design concerns when harvesters are subjected to real vibrations.
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Olt, Jüri, Keio Küüt, Risto Ilves, and Arne Küüt. "Assessment of the harvesting costs of different combine harvester fleets." Research in Agricultural Engineering 65, No. 1 (April 12, 2019): 25–32. http://dx.doi.org/10.17221/98/2017-rae.
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This study discusses practical collection methods of cereal harvesting costs in different agricultural holdings in order to effectively manage combine harvester fleets, make economically reasoned decisions on the exploitation of combine harvesters, reduce harvesting costs and consequently the cost price of cereals. For this purpose, the author used work results of combine harvesters monitored by three randomly selected agricultural holdings, collected practical information on harvesting, analysed this information and provided assessments on the effectiveness of their combine harvester fleet. Evidently, not all combine harvester fleets and combines operate with the same efficiency, as their harvesting costs are different.
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Salem, Marwa S., Shimaa Ahmed, Ahmed Shaker, Mohammad T. Alshammari, Kawther A. Al-Dhlan, Adwan Alanazi, Ahmed Saeed, and Mohamed Abouelatta. "Bandwidth Broadening of Piezoelectric Energy Harvesters Using Arrays of a Proposed Piezoelectric Cantilever Structure." Micromachines 12, no. 8 (August 17, 2021): 973. http://dx.doi.org/10.3390/mi12080973.
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One of the most important challenges in the design of the piezoelectric energy harvester is its narrow bandwidth. Most of the input vibration sources are exposed to frequency variation during their operation. The piezoelectric energy harvester’s narrow bandwidth makes it difficult for the harvester to track the variations of the input vibration source frequency. Thus, the harvester’s output power and overall performance is expected to decline from the designed value. This current study aims to solve the problem of the piezoelectric energy harvester’s narrow bandwidth. The main objective is to achieve bandwidth broadening which is carried out by segmenting the piezoelectric material of the energy harvester into n segments; where n could be more than one. Three arrays with two, four, and six beams are shaped with two piezoelectric segments. The effect of changing the length of the piezoelectric material segment on the resonant frequency, output power, and bandwidth, as well as the frequency response is investigated. The proposed piezoelectric energy harvesters were implemented utilizing a finite element method (FEM) simulation in a MATLAB environment. The results show that increasing the number of array beams increases the output power and bandwidth. For the three-beam arrays, at n equals 2, 6 mW output power and a 9 Hz bandwidth were obtained. Moreover, the bandwidth of such arrays covered around 5% deviation from its resonant frequency. All structures were designed to operate as a steel wheel safety sensor which could be used in train tracks.
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Ramos, Carlos R. G., Kléber P. Lanças, Gabriel A. de Lyra, and Jefferson Sandi. "Fuel consumption of a sugarcane harvester in different operational settings." Revista Brasileira de Engenharia Agrícola e Ambiental 20, no. 6 (June 2016): 588–92. http://dx.doi.org/10.1590/1807-1929/agriambi.v20n6p588-592.
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ABSTRACT The interventions performed during the mechanized harvesting are essential to improve the operational performance of sugarcane harvesters and reduce operational costs. The objective of the present study was to evaluate the fuel consumption of a sugarcane harvester in different forward speeds and engine rotations. Harvesting was conducted in a green cane plot, with the variety RB 855156. Flow meters were installed in the harvester's fuel supply system and an electronic device was used for data acquisition. The experiment was carried out in a completely randomized design in a factorial scheme (3 x 2), using three engine rotations and two forward speeds, with six replicates. Harvesting capacity and fuel consumption per hour, per area and per ton of harvested sugarcane were analyzed. The results were subjected to analysis of variance and means were compared by Tukey test. The variations in engine rotation did not affect the performance for harvesting capacity, but influenced fuel consumption. Forward speed influenced both harvesting capacity and fuel consumption.
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Wang, Zu Yao. "A Nonlinear Piezoelectric Energy Harvester from the Vibration of Magnetic Levitation." Advanced Materials Research 860-863 (December 2013): 594–98. http://dx.doi.org/10.4028/www.scientific.net/amr.860-863.594.
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Vibration-based energy harvester has been widely investigated during the past years. In .order to improve the power-generating ability and enlarge the frequency range of energy harvesters, this paper presents the design and analysis of a new magneto electric energy harvester that uses Terfenol-D/PZT/Terfenol-D laminate to harvest energy from nonlinear vibrations created by magnetic levitation. The mathematical model of the proposed harvester is derived and used in a parametric study. By multi-scale analysis, the frequency-response analysis of the system is obtained and discussed here. It is shown that the systems nonlinearity can broaden the harvesters working bandwidth, thus makes the harvester suitable to work in practical cases.
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Morgan, John P., and Douglas R. Collicutt. "Seed Stripper Harvesters." Ecological Restoration 12, no. 1 (1994): 51–54. http://dx.doi.org/10.3368/er.12.1.51.
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Seliverstov, A. A. "Single grip harvesters." Resources and Technology, no. 5 (2005): 98–101. http://dx.doi.org/10.15393/j2.art.2005.1982.
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Hanikel, Nikita, Mathieu S. Prévot, and Omar M. Yaghi. "MOF water harvesters." Nature Nanotechnology 15, no. 5 (May 2020): 348–55. http://dx.doi.org/10.1038/s41565-020-0673-x.
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Rush, William. "Harvesters with Disabilities." Journal of Religion, Disability & Health 7, no. 4 (February 23, 2004): 65–71. http://dx.doi.org/10.1300/j095v07n04_06.
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Nammari, Abdullah, and Hamzeh Bardaweel. "Design enhancement and non-dimensional analysis of magnetically-levitated nonlinear vibration energy harvesters." Journal of Intelligent Material Systems and Structures 28, no. 19 (March 26, 2017): 2810–22. http://dx.doi.org/10.1177/1045389x17698592.
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Over the past decade, there has been special interest in developing nonlinear energy harvesters capable of operating over a wideband frequency spectrum. Chief among the nonlinear energy harvesting techniques is magnetic levitation–based energy harvesting. Nonetheless, current nonlinear magnetic levitation–based energy harvesting approaches encapsulate design challenges. This work investigates some of the design issues and limitations faced by traditional magnetic levitation–based energy harvesters such as damping schemes and stiffness nonlinearities. Both experiment and model are used to quantify and evaluate damping regimes and stiffness nonlinearities present in magnetic levitation–based energy harvesters. Results show that dry friction, mostly ignored in magnetic levitation–based energy harvesting literature, contributes to the overall energy dissipation. Measured and modeled magnetic forces–displacement curves suggest that stiffness nonlinearities are weak over moderate distances. An enhanced design utilizing a combination of mechanical and magnetic springs is introduced to overcome some of these limitations. A non-dimensional model of the proposed design is developed and used to investigate the enhanced architecture. The unique potential energy profile suggests that the proposed nonlinear energy harvester outperforms the linear version by steepening the displacement response and shifting the resonance frequency, resulting in a larger bandwidth for which power can be harvested.
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Wang, Lingzhi, Ting Tan, Zhimiao Yan, and Zhitao Yan. "Tapered galloping energy harvester for power enhancement and vibration reduction." Journal of Intelligent Material Systems and Structures 30, no. 18-19 (September 22, 2019): 2853–69. http://dx.doi.org/10.1177/1045389x19873409.
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The cantilever beam was commonly designed with uniform cross-section for the galloping energy harvesters. To improve its performance, two tapered galloping energy harvesters are proposed in this work. In the first tapered design, the beam’s thickness is linearly changed with constant width. In the second tapered design, both the beam’s thickness and width are linearly varied. A generalized fluid–structure–electricity coupled distributed-parameter model is established by the Hamilton principle and Gauss law for the tapered galloping energy harvesters. By means of the properties of the Bessel function and the modal analysis method, the exact analytical modal shape of the tapered beam is derived. The effects of the tapered ratio on the beam mass, bending stiffness, electrical field, electromechanical coupling, and piezoelectric capacitance are accounted by the proposed theoretic model. Finite element analyses and wind tunnel experiments are performed, and the results show good agreement with the proposed beam modal shape, corresponding natural frequency and harvested power. The tapered ratio is tuned to realize the even distribution of the piezoelectric strain along the beam length. Compared with the uniform design, the tapered galloping energy harvester exhibits merits on up to [Formula: see text] power enhancement and [Formula: see text] vibration deduction.
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Mokhtar, Maznon M., Baba Md Deros, and Ezrin Hani Sukadarin. "Evaluation of Musculoskeletal Disorders Prevalence during Oil Palm Fresh Fruit Bunches Harvesting Using RULA." Advanced Engineering Forum 10 (December 2013): 110–15. http://dx.doi.org/10.4028/www.scientific.net/aef.10.110.
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Prevalence of work-related musculoskeletal disorders (WMSD) in the agricultural industry is a very serious problem but it is not well investigated and understood. In this paper, the authors have made an attempt to evaluate the prevalence of WMSD in oil palm industry during harvesting fresh fruit bunches (FFB). Data collection was conducted by conducting face-to-face structured interviews with FFB harvesters. In addition, video recording on seven FFB harvesters were conducted while they are performing the harvesting work. Demographic data shows that the mean age of FFB harvester was 41.3 years and 71.4% of them are smokers. Rapid Upper Limb Assessment (RULA) method was used to evaluate the prevalence of WMSD by observing the working postures of the FFB harvesters. RULA analysis of the observed results showed that 83% of the FFB harvesters have scored 7 during harvesting work, which means postural changes must be carried out immediately. Meanwhile, 17% FFB harvesters have scored 5, which means postural change must be carried out soon. Repetitive work is also a main factor that contributes to high prevalence of WMSD among FFB harvesters while they are pulling and pushing the FFB.
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Špokas, L., V. Adamčuk, V. Bulgakov, and L. Nozdrovický. "The experimental research of combine harvesters." Research in Agricultural Engineering 62, No. 3 (August 30, 2016): 106–12. http://dx.doi.org/10.17221/16/2015-rae.
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The paper presents results of the experimental research of a middle-size combine harvester when used for harvest of winter wheat and spring barley in heavy harvest conditions. Based on the results obtained, it was possible to determine the effect of field conditions on the crop mass flow in combine harvester, grain losses, fuel consumption, and combine harvester field performance. It was found that grain moisture content and conditions of the crop stand have a significant effect on the work indicators of the combine harvester when compared with its technological parameters and crop mass flow.
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Kumhála, F., Z. Kvíz, J. Mašek, and P. Procházka. "The measurement of plant residues distribution quality after harvest by conventional and axial combine harvesters." Plant, Soil and Environment 51, No. 6 (November 19, 2011): 249–54. http://dx.doi.org/10.17221/3582-pse.
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This paper concerns the evaluation of the husk and straw distribution quality measurement on different commonly used combine harvesters. The plant residues can significantly influence the next plant germination and growth, especially when they are unevenly placed on the field surface. The experiments were realised during the harvesting season in years 2001, 2002 and 2003. All machines were evaluated under normal operational conditions by winter wheat and oil rape harvest. For plant residues distribution quality evaluation the Christiansen’s coefficient was calculated. The most important outcome from the measurement is that the distribution pattern of husk and straw depends on instantaneous material feed rate through the harvester. The higher material feed rate the worse regularity of husk and straw distribution. Axial combine harvesters break up straw more intensively then tangential combine harvesters. Straw crushers on tangential combine harvesters are therefore more loaded and need more attention from the crushing and distribution quality point of view. On the contrary, on axial combine harvesters most material goes on cleaning sieves and more attention should be paid to this small particles distribution.
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Nanda, Aditya, Puneet Singla, and M. Amin Karami. "Conjugate unscented transformation–based uncertainty analysis of energy harvesters." Journal of Intelligent Material Systems and Structures 29, no. 18 (September 21, 2018): 3614–33. http://dx.doi.org/10.1177/1045389x18798945.
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This article presents a probabilistic approach to investigate the effect of parametric uncertainties on the mean power, tip deflection, and tip velocity of linear and nonlinear energy harvesting systems. Recently developed conjugate unscented transformation algorithm is used to compute the statistical moments of the output variables with multidimensional Gaussian uncertainty in parameters. The principle of maximum entropy is used to construct the probability density function of output variables from the knowledge of obtained statistical moments. The probability density functions for mean power were significantly complicated in shape with two and three distinct peaks for the nonlinear monostable and nonlinear bistable harvesters, respectively. Monte-Carlo simulations with N = 8 × 104 samples for monostable harvester and N = 6.5 × 104 samples for bistable harvester were used for validating the probability density functions. It is concluded that conjugate unscented transformation methodology affords a significant computational advantage without compromising accuracy. In addition, using conjugate unscented transformation method, we show that the dependence of mean power on parameters (excitation frequency, excitation amplitude, etc.), when multidimensional uncertainties are present, is decidedly different relative to a purely deterministic trend. The discrepancy in predicted power between the deterministic and uncertain trends for the monostable harvester, for instance, reach a maximum of 100%, 234%, and 110% for base frequency, base acceleration, and magnet gap, respectively. The deterministic trend consistently overestimates the harvested power relative to the uncertain trends. This work, therefore, may have applications in evaluating “worst case scenario” for harvested power. The major advantage of the presented methodology relative to extant techniques in energy harvesting literature is the accurate and computationally effective applicability to multidimensional uncertainty in parameters.
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Mann, Brian P., David AW Barton, and Benjamin AM Owens. "Uncertainty in performance for linear and nonlinear energy harvesting strategies." Journal of Intelligent Material Systems and Structures 23, no. 13 (March 28, 2012): 1451–60. http://dx.doi.org/10.1177/1045389x12439639.
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Vibrational energy harvesters are often linear mass–spring–damper-type devices, which have their resonant frequency tuned to the dominant vibration frequency of their host environment. As such, they can be highly sensitive to uncertainties, which may arise from the imprecise characterization of the host environment or, alternatively, from manufacturing defects and tolerances. It has previously been claimed that the use of nonlinear energy harvesters may be one way to alleviate the problems of these uncertainties. This article presents a systematic uncertainty propagation study of a prototypical electromagnetic energy harvester. More specifically, the response of a linear harvester in the presence of parametric uncertainty is compared to the response of harvesters containing some common forms of nonlinearity, that is, hardening, softening, or bistability. Analytical solutions are used in combination with presumed levels of parametric uncertainty to quantify the resulting uncertainty in the power output. Consequently, these studies can determine the regions in the parameter space where a nonlinear strategy may outperform a more traditional linear approach.
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Marshall, Dale E. "Mechanical Harvesting of Peppers." HortScience 30, no. 4 (July 1995): 754B—754. http://dx.doi.org/10.21273/hortsci.30.4.754b.
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For nearly 30 years, more than 75 different groups: producers, entrepreneurs, engineers, processors, consultants, state or federal researchers, or manufacturers have constructed over 195 harvesters attempting to mechanize the harvest of Capsicum peppers. Countries testing experimental harvesters include: Bulgaria, Hungary, Israel, Italy, Spain, the United States, and the former Soviet Union. Over 25 principles have been tested. In 1980, there were 10 different university, state, or federal research agencies experimenting with pepper harvest mechanization. However, in 1990, there were no active mechanization projects. At least 13 patents have been identified that have been issued on pepper harvesters and 65 patents on harvesting elements or principles for other crops that have been tested or might be used to harvest peppers. Interest in mechanization has resumed in the United States and a number of commercial harvesters are available. Harvester usage is expected to increase significantly by the year 2000.
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Lan, Chunbo, Yabin Liao, Guobiao Hu, and Lihua Tang. "Equivalent impedance and power analysis of monostable piezoelectric energy harvesters." Journal of Intelligent Material Systems and Structures 31, no. 14 (June 19, 2020): 1697–715. http://dx.doi.org/10.1177/1045389x20930080.
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Nonlinearity has been successfully introduced into piezoelectric energy harvesting for power performance enhancement and bandwidth enlargement. While a great deal of emphasis has been placed by researchers on the structural design and broadband effect, this article is motivated to investigate the maximum power of a representative type of nonlinear piezoelectric energy harvesters, that is, monostable piezoelectric energy harvester. An equivalent circuit is proposed to analytically study and explain system behaviors. The effect of nonlinearity is modeled as a nonlinear stiffness element mechanically and a nonlinear capacitive element electrically. Facilitated by the equivalent circuit, closed-form solutions of power limit and critical electromechanical coupling, that is, minimum coupling to reach the power limit, of monostable piezoelectric energy harvesters are obtained, which are used for a clear explanation of the system behavior. Several important conclusions have been drawn from the analytical analysis and validated by numerical simulations. First, given the same level of external excitation, the monostable piezoelectric energy harvester and its linear counterpart are subjected to the same power limit. Second, while the critical coupling of linear piezoelectric energy harvesters depends on the mechanical damping ratio only, it also depends on the vibration excitation and magnetic field for monostable piezoelectric energy harvesters, which can be used to adjust the power performance of the system.
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Harmon, Joshua D., Brian D. Luck, Kevin J. Shinners, Robert P. Anex, and Jessica L. Drewry. "Time-Motion Analysis of Forage Harvest: A Case Study." Transactions of the ASABE 61, no. 2 (2018): 483–91. http://dx.doi.org/10.13031/trans.12484.
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Abstract. Forage harvest is a time and energy intensive process requiring the coordination of multiple pieces of equipment. Detailed characterizations of the time spent in each work state for each piece of equipment would increase the understanding of process inefficiencies and aid in development of optimization tools. Geospatial and controller area network (CAN) machine data were recorded on forage harvesters and transport equipment, during two types of harvest operations, to quantify utilization of harvesters and transports as well as transport productivity. The data collection and processing method was successful in identifying work states for forage harvesters and transports. The results indicated that overall utilization of the harvester for harvesting was 61% and dependent on transport availability. The portion of total operational time spent in the idle work state (idle utilization) was 10% to 20% for transports and 18% to 23% for harvesters. A new metric for transport productivity was developed and found to be highly dependent on transport capacity ranging from 125 to 49 Mg km h-1 for semi-trucks and smaller transports, respectively. The proposed data collection methods and productivity metrics could be used to optimize the forage harvest process to reduce idle time and maintain crop quality. Keywords: Controller area network, Cycle analysis, Forage harvester, Global positioning system.
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Wang, Jie, Mostafa R. A. Nabawy, Andrea Cioncolini, Alistair Revell, and Samuel Weigert. "Planform Geometry and Excitation Effects of PVDF-Based Vibration Energy Harvesters." Energies 14, no. 1 (January 3, 2021): 211. http://dx.doi.org/10.3390/en14010211.
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In the present paper, we report a systematic investigation of planform geometry and excitation level effects on the dynamics and power generation characteristics of polyvinylidene difluoride (PVDF)-based cantilevered vibration energy harvesters. Piezoelectric vibration energy harvesters provide a promising energy harvesting solution for widespread use of wireless sensors in remote locations. Highly flexible PVDF polymers offer resonant frequencies at suitable range for harvesting mechanical energy within low-frequency applications, though information on the efficient sizing of these devices is currently limited. We test the response of a set of eight harvesters to typical vibration sources excitation levels in the range 0.2–0.6 g. This set comprises four widths and two lengths, incrementing each time by a factor of two. The selected range of dimensions is sufficient to identify optimal power output versus width for both lengths tested. This optimal width value depends on excitation amplitude in such a way that narrower harvesters are more suited for small excitations, whereas wider harvesters perform better upon experiencing large excitations. Non-linear effects present in longer harvesters are demonstrated to significantly reduce performance, which motivates the selection of planform dimensions inside the linear range. Finally, we explore the correlation of performance with various geometric quantities in order to inform future design studies and highlight the value of using the second moment of planform area to measure harvester efficiency in terms of power density. This points towards the use of harvesters with non-rectangular planform area for optimal performance.
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Santinato, Felipe, Carlos Diego da Silva, Rouverson Pereira da Silva, Antônio Tassio Silva Ormond, Victor Afonso Reis Gonçalves, and Roberto Santinato. "Operational cost of mechanized harvesting of first-crop coffee." Australian Journal of Crop Science, no. 13(09):2019 (September 20, 2019): 1503–10. http://dx.doi.org/10.21475/ajcs.19.13.09.p1727.
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The use of adapted harvesters for harvesting first-crop coffee requires a lower cost and exhibits a higher efficiency than manual harvesting. In view of this, the present study aimed to analyze the operational cost of mechanized harvesting of first-crop coffee. The experiment was conducted in a factorial scheme (2 × 3) + 1 and outlined in randomized blocks with five replications. There were seven treatments: two automotive harvesters (conventional and adapted) with times of operations for each harvester (1, 2 and 3 time operations) and manual harvesting. We tested these treatments in a young coffee crop planted in Catalão, GO, irrigated by Pivot, with 1.5 m of height. We measured the lost coffee, coffee harvest, remaining coffee before the operation to obtain efficient parameters and with the prices of the operations and the costs of the treatments. When operated once and three times, the adapted harvester required a lower transfer cost than the conventional harvester. Moreover, the adapted harvester showed no difference in cost between each operation. The cost reduction by mechanized harvesting varied from 23.96 to 59.9 %, depending on the frequency of the mechanized operations. In conclusion, it is efficient to harvest the young coffee with the adapted harvesters reducing the cost of coffee harvesting.
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Astafyiev, V. L., and V. A. Golikov. "DETERMINING THE RANGE OF COMBINE HARVESTERS AND HEADERS FOR KAZAKHSTAN REGIONS." Agricultural Machinery and Technologies 12, no. 4 (September 27, 2018): 10–15. http://dx.doi.org/10.22314/2073-7599-2018-12-4-10-15.
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The fleet of combine harvesters in the Republic of Kazakhstan consists of 3-, 4-, 5- and 6-class harvesters, and 3- and 4- class harvesters make up for almost 82% of the fleet. According to the data provided by the Kazakhstan Ministry of Agriculture, 60% of grain harvesters have a lifespan of more than 10 years. (Research purpose) To determine the range of grain harvesters and headers for Kazakhstan regions in view of ongoing technical re-equipment. (Materials and methods) The range of grain harvesters should be determined according to the yield of harvested crops, the size of crop area on separate farms and in the region, the availability of machine operators as well as climatic conditions of the regions. (Results and discussions). The authors have analyzed the actual yield of grain crops in Kazakhstan regions, determined its possible expected level, and analyzed the number of machine operators required for available crop area, the number of small, medium and large-scale farms and climatic conditions during the harvest period in Kazakhstan regions. The efficiency of harvesters of different classes with headers of various operating width has been estimated taking into account the expected yield. Matching the obtained results to the yield data, organizational-and-economic and climatic conditions, and introducing appropriate limits, the authors have determined the range of grain harvesters for Kazakhstan regions. (Summary) It has been found that the harvesters of class 5, 6 and 4 are more effective under conditions of northern and central Kazakhstan regions provided they are equipped with wide-cut headers for direct harvesting. In southern, western and eastern Kazakhstan regions, where grain crops are cultivated on dry soils with an insufficient moisture content, combine harvesters of class 3 and 4 should be primarily used.
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Tien, Meng-Hsuan, and Kiran D’Souza. "Method for controlling vibration by exploiting piecewise-linear nonlinearity in energy harvesters." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 476, no. 2233 (January 2020): 20190491. http://dx.doi.org/10.1098/rspa.2019.0491.
Full textAbstract:
Vibration energy is becoming a significant alternative solution for energy generation. Recently, a great deal of research has been conducted on how to harvest energy from vibration sources ranging from ocean waves to human motion to microsystems. In this paper, a theoretical model of a piecewise-linear (PWL) nonlinear vibration harvester that has potential applications in variety of fields is proposed and numerically investigated. This new technique enables automatic frequency tunability in the energy harvester by controlling the gap size in the PWL oscillator so that it is able to adapt to changes in excitations. To optimize the performance of the proposed system, a control method combining the response prediction, signal measurement and gap adjustment mechanism is proposed in this paper. This new energy harvester not only overcomes the limitation of traditional linear energy harvesters that can only provide the maximum power generation efficiency over a narrow frequency range but also improves the performance of current nonlinear energy harvesters that are not as efficient as linear energy harvesters at resonance. The proposed system is demonstrated in several case studies to illustrate its effectiveness for a number of different excitations.