The underlying mechanism of variety–water–nitrogen–stubble damage interactions on yield formation in ratoon rice with low stubble height under mechanized harvesting

Agronomic measures are the key to promote the sustainable development of ratoon rice by reducing the damage from mechanical crushing to the residual stubble of the main crop, thereby mitigating the impact on axillary bud sprouting and yield formation in ratoon rice. This study used widely recommended conventional rice Jiafuzhan and hybrid rice Yongyou 2640 as the test materials to conduct a four-factor block design field experiment in a greenhouse of the experimental farm of Fujian Agricultural and Forestry University, China from 2018 to 2019.The treatments included fertilization and no fertilization, alternate wetting and drying irrigation and continuous water flooding irrigation, and plots with and without artificial crushing damage on the rice stubble. At the same time, a 13C stable isotope in-situ detection technology was used to fertilize the pot experiment. The results showed significant interactions among varieties, water management, nitrogen application and stubble status.Relative to the long-term water flooding treatment, the treatment with sequential application of nitrogen fertilizer coupled with moderate field drought for root-vigor and tiller promotion before and after harvesting of the main crop, significantly improved the effective tillers from low position nodes. This in turn increased the effective panicles per plant and grains per panicle by reducing the influence of artificial crushing damage on rice stubble and achieving a high yield of the regenerated rice. Furthermore, the partitioning of 13C assimilates to the residual stubble and its axillary buds were significantly improved at the mature stage of the main crop, while the translocation rate to roots and rhizosphere soil was reduced at the later growth stage of ratooning season rice. This was triggered by the metabolism of hormones and polyamines at the stem base regulated by the interaction of water and fertilizer at this time. We therefore suggest that to achieve a high yield of ratoon rice with low stubble height under mechanized harvesting, the timely application of nitrogen fertilizer is fundamental,coupled with moderate field drying for root-vigor preservation and tiller promotion before and after the mechanical harvesting of the main crop.

Dynamic analysis of a novel multilink-spring mechanism for vibration isolation and energy harvesting

Due to technical limitations,existing vibration isolation and energy harvesting(VIEH)devices have poor performance at low frequency.This paper proposes a new multilink-spring mechanism(MLSM)that can be used to solve this problem.The VIEH performance of the MLSM under harmonic excitation and Gaussian white noise was analyzed.It was found that the MLSM has good vibration isolation performance for low-frequency isolation and the frequency band can be widened by adjusting parameters to achieve a higher energy harvesting power.By comparison with two special cases,the results show that the MLSM is basically the same as the other two oscillators in terms of vibration isolation but has better energy harvesting performance under multistable characteristics.The MLSM is expected to reduce the impact of vibration on high-precision sensitive equipment in some special sites such as subways and mines,and at the same time supply power to structural health monitoring devices.

Bidirectional rotating direct-current triboelectric nanogenerator with self-adaptive mechanical switching for harvesting reciprocating motion

Amid the growing interest in triboelectric nanogenerators(TENGs)as novel energy-harvesting devices,several studies have focused on direct current(DC)TENGs to generate a stable DC output for operating electronic devices.However,owing to the working mechanisms of conventional DC TENGs,generating a stable DC output from reciprocating motion remains a challenge.Accordingly,we propose a bidirectional rotating DC TENG(BiR-TENG),which can generate DC outputs,regardless of the direction of rotation,from reciprocating motions.The distinct design of the BiR-TENG enables the mechanical rectification of the alternating current output into a rotational-direction-dependent DC output.Furthermore,it allows the conversion of the rotational-direction-dependent DC output into a unidirectional DC output by adapting the configurations depending on the rotational direction.Owing to these tailored design strategies and subsequent optimizations,the BiR-TENG could generate an effective unidirectional DC output.Applications of the BiR-TENG for the reciprocating motions of swinging doors and waves were demonstrated by harnessing this output.This study demonstrates the potential of the BiR-TENG design strategy as an effective and versatile solution for energy harvesting from reciprocating motions,highlighting the suitability of DC outputs as an energy source for electronic devices.

Design, Modeling and Analysis of Implementing a Multilayer Piezoelectric Vibration Energy Harvesting Mechanism in the Vehicle Suspension

This paper deals with the design, modeling and analysis of implementing a Multilayer Piezoelectric Vibration Energy Harvesting (ML PZT VEH) Mechanism in the vehicle suspension. The principle of work of the proposed ML PZT VEH mechanism is reducing the relative motion of the suspension, amplifying the applied force to the PZT by a specific design of mechanism and combining a single layer PZT into multilayer PZT to increase the produced electricity. To maintain the performance of suspension as the original suspension, the ML PZT VEH mechanism is mounted in series with the spring of the suspension. The proposed ML PZT VEH mechanism and its implementation to the vehicle suspension were mathematically modeled. Responses of the vehicle before and after implementing ML PZT VEH mechanism were simulated. The results show the proposed mechanism can produce output voltage of 2.75 and power of 7.17 times bigger than direct mounting to the vehicle suspension. And the simulation result shows that mounting ML PZT VEH mechanism in series with the spring of the vehicle suspension does not change the performance of suspension.

Pricing Mechanism of China’s Trans-regional and Trans-provincial Electricity Trading

With the large-scale development of Chinese electric power, the contradiction of China’s energy supply and demand that reverse distributed is very prominent, therefore, promoting electricity trading is one of the important measures to get optimized configuration of energy resources in nationwide. For the two kinds of trading method, the “power point to the grid” trading and the “grid to grid” trading, this paper designed pricing mechanism model, and took one area as an example, we analyzed the impact of the participants by using different pricing mechanism, and put forward reasonable policy proposals for China’s pricing mechanism of trans-regional and trans-provincial electricity trading.

Effects of Planting Density on Yield and Mechanical Harvesting Loss Rate of Brassica napus L.

[Objective] This study aimed to explore agronomical measures to reduce the mechanical harvesting loss of rapeseed. [Method] Two rapeseed cultivars, Ningza 19 and Ningza 21, with certain pod-cracking resistance, were employed in field experiments. The two-factor split plot design and randomized complete block design were adopted. The rapeseed seeds were directly sowed with four different seeding rates （1.50, 2.25, 3.00 and 3.75 kg/hm2）. A total of four treatments were designed （112 500, 225 000, 337 500 and 450 000 plants/hm2）. After ripe, the rapeseed was harvested with harvester. Then the yield and harvesting loss rate were determined. [Result] When the planting density ranged from 112 500 to 450 000 plants/hm2, the mechanical harvesting loss rate was decreased with the increase of planting density （Ningza 19, 7.54%-4.01%; Ningza 21, 7.19%-3.81%）. The total loss rates were all below 5% for the high plant densities, 337 500 and 450 000 plants/hm2. High planting density had certain regulating effects on plant type of rapeseed, including reducing plant height, reducing biomass per plant, reducing branch pod numbers per plant, weakening crossing and tangling among stems and improving ripening uniformity of pods. All the changes above were all conducive to reducing mechanical harvesting loss. In addition, the test results showed after the pods grew to maturity, especially when pods were yellow and the moisture content in grains was reduced to 11%, the mechanical harvesting loss only accounted for about 1% of the total field loss. In addition, the shattering loss, caused by mild col- lision, represented more than 90%, and the cleaning loss, occurred during the threshing and cleaning process, represented 4%-8% of the total field loss. The un- harvesting loss accounted for approximately 1% of the total loss. The shattering loss is closely related to cultivar characteristics, planting density, production level and other agronomic factors. The cleaning loss is determined by properties of harvesting machines. The unharvesting loss depends on mechanical properties ad skills of workers or farmers who drive harvesting machines. [Conclusion] In order to reduce mechanical harvesting loss, the rapeseed production should be improved from the perspectives of agricultural machinery and agronomic measures.

Screening and Breeding of Sweetpotato Varieties Suitable for Mechanical Harvesting

The lower degree of mechanical harvesting is a bottleneck hindering the healthy development of sweetpotato industry in China, while the mismatching be- tween agricultural machinery and agronomy is one of the main factors for poor me- chani.cal harvesting. In this study, total five sweetpotato varieties were selected, and the effects of different shapes and sizes on mechanical harvesting of sweetpotato were investigated. The results showed that the breakage rate of Xuzishu 5 was lowest, so it is more suitable for mechanical harvesting in field. At the same time, the correlations between sweetpotato shape, breakage rate and exposure rate were analyzed. It was found that there was a significant linear correlation between sweet- potato shape and breakage rate （P〈0.01）; the higher the flat rate is, the higher the breakage rate is; and sweetpotato shape had no significant effect on exposure rate. Therefore, tuberous root with lower flat rate, as well as better agronomic characters should be selected in the breeding process of new sweetpotato varieties.

A Study of Mechanization of Cotton Harvesting in India and Its Implications

Cotton is one of the most important crops throughout the history of India and it also plays an important role in social and economic aspects of the Indian society in the present age. Recent technological advances and trade liberalization have made India a major player in international cotton markets. In the year 2011-2012, India was the world＇s second largest producer, consumer and exporter of cotton. The increasing role of the Indian cotton sector in international markets is a direct challenge to other major players like the US. Within this context, a better understanding of the Indian cotton sector and the impact of mechanization on cotton cultivation are needed. The overall objective of this paper is to assess the competitiveness of Indian cotton producers and potential implications for India as a competitor in the world cotton market if it mechanizes harvesting of cotton. The results demonstrate that the net income of the Indian cotton farmers will increase considerably with the mechanization of cotton harvesting. But the adoption of the practice of harvesting cotton by mechanical means is possible only if efforts from many private and public agencies come together. In that scenario, the cotton production in India can increase considerably which can impact the international markets.

Status and Constrain for Mechanization of Rice Harvesting System in Bangladesh

To know the position, problems and suggestion of harvest mechanization of rice, the study conducted in 21 upzillas under seven regions (Dhaka, Mymensingh, Sylhet, Comilla, Bogra, Rajshahi and Rangpur) based on different agro-climatic condition and cropping intensity and 126 farmers participated in the interview. For collecting data, a structured questionnaire was used and statistical analysis of the collected data was carried out. In study area, the average cultivable area was 225 to 1239 decimal (1 decimal = 40 m2) and 97.60% farmer reaping by sickle and only 0.80% used combine harvester. Cut paddy transported by head (13.49%), shoulders (12.7%) or both of them of 11.11% farmer and 44.44% of farmers used small truck or field threshed. Threshing was mainly done using (49.21%) closed drum thresher and open drum thresher (26.20%), likewise 1 of 126 farmer use head-feed combine harvester. The study area, most farmers (37.3%) used kula for the cleaning of rice, but only 8.74% of farmers used winnower. In considerable amount, 80.95% of farmers had machinery, while the remaining (19.05%) did not have machines. Farmers agreed that harvesting was a labor-intensive method (35.71%) and time consuming (28.57%). Transporting of harvested paddy was dangerous and painful for head, shoulder, hand, waist, backbone, leg, etc. With mechanization and the introduction of machinery, 40.48% of farmers identified the main ceiling as the price of the machine and information/lack of credit system (21.43%). In survey area, most farmers (36.51%) identified the vital advantage of mechanized harvesting as lower labor requirement, while 21.43% of farmers said that a lower loss of rice. All farmers who participated in the interview expressed their need for machinery and mentioned agricultural credit with easy terms and conditions, subsidy for buying machinery and the ensuring of a fair market price for their rice.

Design and dynamic analysis of integrated architecture for vibration energy harvesting including piezoelectric frame and mechanical amplifier

Vibration energy harvesters(VEHs) can transform ambient vibration energy to electricity and have been widely investigated as promising self-powered devices for wireless sensor networks, wearable sensors, and applications of a micro-electro-mechanical system(MEMS). However, the ambient vibration is always too weak to hinder the high energy conversion efficiency. In this paper, the integrated frame composed of piezoelectric beams and mechanical amplifiers is proposed to improve the energy conversion efficiency of a VEH. First, the initial structures of a piezoelectric frame(PF) and an amplification frame(AF) are designed. The dynamic model is then established to analyze the influence of key structural parameters on the mechanical amplification factor. Finite element simulation is conducted to study the energy harvesting performance, where the stiffness characteristics and power output in the cases of series and parallel load resistance are discussed in detail. Furthermore, piezoelectric beams with variable cross-sections are introduced to optimize and improve the energy harvesting efficiency. Advantages of the PF with the AF are illustrated by comparison with conventional piezoelectric cantilever beams. The results show that the proposed integrated VEH has a good mechanical amplification capability and is more suitable for low-frequency vibration conditions.

Evaluation of Visible Losses and Damage to the Ratoon Cane in the Mechanized Harvesting of Sugarcane for Different Displacement Speeds

This study aimed at quantitatively evaluating the sugarcane losses and the damage caused to the ratoon cane while using the Case IH A8800 harvester in different displacement speeds;it was conducted in the municipality of Campos dos Goytacazes, in Rio de Janeiro, Brazil. Three speeds were used as treatment (2 km&middoth-1, 3 km&middoth-1, and 4.5 km&middoth-1), and each treatment was composed of six rows of harvested ratoon, each with a length of 290 m. In order to evaluate the quantitative losses in t&middotha-1 and the percentage of losses, the remaining sugarcane, left on the field after harvesting, was collected. The sampling frame was set to every 50 m, dividing the borders by 40 m;the measurement for each sampling area was of 20 m2, with five repetitions. In order to evaluate the damage caused to the ratoon canes, we chose a visual methodology to classify the damage degrees, ranging from one to four. There was no significant difference in losses when comparing different speeds. Therefore, it is more advantageous and economically viable to use the speed of 4.5 km&middoth-1, which collects more in less time.

Analysis on Mechanical Grain Harvesting Characteristics of Different New Maize Varieties

In order to screen new varieties of suitable mechanical grain harvesting maize, the main agronomic traits, stem traits and harvesting traits of maize in the harvest period were studied through taking 18 main varieties and newly-tested varieties in Liaoning Province as materials. It obtained the following results. Between different maize varieties, there was significant difference in the mechanical grain yield, and the quality difference was also significant. Ten test varieties including Tieyan 818 and Danyu 311 obtained higher yield than the control variety. The moisture content at harvesting was 26.0%-30.4%, the average moisture content was 28.22%, the average breaking rate was 6.52%, the average impurity rate was 1.91%, and the average yield loss rate was 6.33%. Danyu 212, Tieyan 58, Dika 516 and Danyu 801 had higher yield, and the grain moisture content, broken rate, impurity rate and yield loss rate were relatively low, so these varieties are suitable for promoting mechanical harvesting. Among the 8 traits surveyed, the traits positively correlated with yield were the percentage of broken stalks, degree of lodging, moisture content at harvesting, and percentage of kernel weight in ear weight, and traits negatively correlated with the yield included plant height, ear height, percentage of bare plants, and degree of lodging. Therefore, high moisture content is the main problem in the mechanical grain harvesting of maize, it is required to properly select early maturing varieties.

Effects of Mechanical Harvesting on Sugarcane Stubble Quality and Growth of Ratoon

The experiment was conducted with the traditional manual harvesting and mechanical harvesting of sugarcane,to compare the effects of different harvesting method on the sugarcane stubble quality and the growth of ratoon.The experimental results are as follows.(i) The stubble height and breaking stubble rate of mechanical harvesting was significantly higher than manual harvesting,the stubble height of lodging species and difficult defoliation species increased in mechanical harvesting condition.Varieties with higher levels of fiber had lower rate of broken stubble.(ii) The effects of mechanical harvesting on germination of next year ratoon were quite different due to different varieties,indicating that the better perennial species have less impact than the poor perennial species.(iii) Compared with manual harvesting,mechanical harvesting had slightly higher plant height and single-stem weight and less effective stems number,the difference of cane yield was not significant,but sucrose content increased 0.53%.(iv) Mechanical harvesting combining with leaves crushing could reduce the impact on the germination of ratoon,improve the single-stem weight and increase the effective number of stems.

Influence of Cutting Stages and Sugarcane Varieties on Sucrose Content in a Brazilian Power Plant with Mechanized Harvesting

This study, carried out in a sugarcane mill located in the center-west region of Sao Paulo state, Brazil, aimed to evaluate the association of sucrose amount （POL%） with sugarcane varieties and cutting stages using mechanized harvesting. A two-way analysis of variance （ANOVA）, complemented by multiple comparison tests, was used in order to identify the effects of variety types and cutting stages on the sugarcane POL% content. An interaction between the sugarcane variety and the cutting stage was observed; therefore, both two factors cannot be independently evaluated regarding POL%. In addition, it was found that the sucrose amount from the plant production in the evaluated period presented significant differences between the cutting stages only for one variety, namely CTC2, which was different from the others in most of the cutting stages. Considering the observed results, it can be concluded that analyzing sucrose amount statistically in the mill production can allow producers to posteriorly better monitor information on the sugarcane varieties harvested under mechanized processes.

Effects of Mechanical Harvesting of Main Crop on Soil Rolling and Yield of Ratooned Rice

[Objectives]To study the effect of mechanical harvesting of main crop on soil rolling and yield of ratooned rice.[Methods]In this study,the harvesting method was optimized and improved through field research and theoretical research.[Results]Compared with farmers'habits,the mechanical harvesting method could significantly increase the working area per unit time and reduce the rolling area in the field,but it would increase the rolling rate of the land or transfer area.At the same time,the optimization method could reduce the soil bulk density in the primary rolling area,but it had no significant impact on soil compactness.[Conclusions]Compared with the farmer's customary method,the optimization method could reduce the crushing and damage of rice piles in the field,increase the seedling rate and panicle extraction rate,thus increasing the yield of rice in the ratooning season.

Visible Losses in Mechanized Harvesting of Sugarcane Using the Case IH A4000 Harvester

Sugarcane is a major Brazilian agricultural product. The area cultivated in the state of Rio de Janeiro for the 2011-12 crop was of 41.31 thousand hectares. The process of mechanized harvesting of the crop still has many visible losses of raw materials caused by several factors. This study aimed at evaluating the visible losses of sugarcane and ratoon damage using the Case A4000 harvester and was conducted in the municipality of Campos dos Goytacazes, in the state of Rio de Janeiro, Brazil. The materials left on the field by the harvester were collected in six ratoon cane rows, with a length of 350 m, setting the frame sampling to every 50 m. The sampling area consisted of 20 m2, with eight repetitions. The losses were calculated in t&middotha-1 and in %. The comparison of averages was performed by using the confidence interval, constructed by statistical “t” at 5% probability to compare the types of losses. The estimated productivity of the area was of 54 t&middotha-1. The differences between the types of losses were significant. The billets and splinters were found in greater quantity.

Broadband energy harvesting via magnetic coupling between two movable magnets

Harvesting energy from ambient mechanical vibrations by the piezoelectric effect has been proposed for powering microelectromechanical systems and replacing batteries that have a finite life span. A conventional piezoelectric energy harvester （PEH） is usually designed as a linear resonator, and suffers from a narrow operating bandwidth. To achieve broadband energy harvesting, in this paper we introduce a concept and describe the realization of a novel nonlinear PEH. The proposed PEH consists of a primary piezoelectric cantilever beam coupled to an auxiliary piezoelectric cantilever beam through two movable magnets. For predicting the nonlinear response from the proposed PEH, lumped parameter models are established for the two beams. Both simulation and experiment reveal that for the primary beam, the introduction of magnetic coupling can expand the operating bandwidth as well as improve the output voltage. For the auxiliary beam, the magnitude of the output voltage is slightly reduced, but additional output is observed at off-resonance frequencies. Therefore, broadband energy harvesting can be obtained from both the primary beam and the auxiliary beam.

Complete Charging for Piezoelectric Energy Harvesting System

Under an in-phase assumption, the complete charging for an energy harvesting system is studied, which consists of a piezoelectric energy harvester(PEH), a bridge rectifier, a filter capacitor, a switch, a controller and a rechargeable battery. For the transient charging, the results indicate that the voltage across the filter capacitor increases as the charging proceeds, which is consistent with that reported in the literature. However, a new finding shows that the charging rate and energy harvesting efficiency decrease over time after their respective peak values are acquired.For the steady-state charging, the results reveal that the energy harvesting efficiency can be adjusted by altering the critical charging voltage that controls the transition of the system. The optimal energy harvesting efficiency is limited by the optimal efficiency of the transient charging. Finally, the relationship between the critical charging voltage and the equivalent resistance of the controller and rechargeable battery is established explicitly.

Past,present and future of industrial plantation forestry and implication on future timber harvesting technology

Plantation forests are established,and expanding,to satisfy increasing global demand for timber products.Shifting societal values,such as safety,productivity,environmental,quality and social are influencing the plantation forestry sector.This is primarily driven through an ever increasing world population,which in turn influences the way nations view the value systems by which they live.More people require more resources-also forest products.Also,the availability of information is influencing the pace of technological development.These changes could result in a difference in the management of plantations that could affect the forest engineering systems of the future.This review aimed to summarize the current status of plantation forests;summarize future developments and possible scenarios in forest plantation management for the various products;and assess whether these developments in a plantation environment could affect the harvesting systems used.Factors influencing the form of plantations include the type and nature of the plantation owner;the change in demand for different and new forest products;climate change factors,including the use of biomass for energy,carbon sequestration and trading;ecosystem services and other products and services;and sustainability certification of forest management.The impact and influence of these factors were summarised into a series of key drivers that will influence the technology used in harvesting machines,as well as the choice of harvesting machines,systems and methods.These drivers were the effect of variations in tree size,the expansion of plantation areas onto more difficult terrain,diversity in plantation design,increased attention towards site impacts and the increased use of biomass for energy.Specific information is provided regarding how the harvesting systems could be affected.

Design and Analysis of a Mechanical Device to Harvest Energy from Human Footstep Motion

Portable electronics is usually powered by battery,which is not sustainable not only to the longtime outdoor use but also to our living environment.There is rich kinetic energy in footstep motion during walking,so it is ideal to harvest the kinetic energy from human footstep motion as power source for portable electronic devices.In this paper,a novel mechanism based on dual-oscillating mode is designed to harvest the kinetic energy from footstep motion.The harvester contains two oscillating sub-mechanisms：one is spring-mass oscillator to absorb the vibration from external excitation,i.e.,the footstep motion,and the other is cantilever beam with tip mass for amplifying the vibration.Theoretic analysis shows that the dual-oscillating mechanism can be more effectively harness the foot step motion.The energy conversion sub-mechanism is based on the electromagnetic induction,where the wire coils fixed at the tip end of the cantilever beam serves as the slider and permanent magnets and yoke form the changing magnetic field.Simulation shows that the harvester,with total mass 70 g,can produce about 100 mW of electricity at the walking speed of 2 steps per second.