Harvesting Model Research Articles

Sum-rate maximization for a distributed space-time block code-aided cooperative NOMA with energy harvesting

AbstractIn this paper, we exploit the spatial and transmission diversities in cooperative non-orthogonal multiple access (C-NOMA) networks to improve the system sum-rate. To achieve this, we propose a user-pairing scheme where near-field user pairs serve as relays for user pairs in the far-field region. Based on this pairing scheme, we incorporate a space-time block code transmission technique at the near-field user pairs to maximize the transmission diversity in the cooperative phase. Moreover, we consider a non-linear energy harvesting model at the near-field user pair to alleviate the problem of energy consumption during the cooperative transmission phase. Further to this, we formulate a sum-rate maximization problem that is addressed from the viewpoint of joint power allocation factor and power splitting ratio optimization. We develop a low-computational iterative algorithm based on the concepts of the Stackelberg game and the Nash bargaining solution. We benchmark our findings with different scenarios, such as energy harvesting C-NOMA with a fixed power allocation factor and power splitting ratio, energy harvesting C-NOMA without STBC, non-cooperative NOMA, and orthogonal multiple access. The results obtained via simulations outperform the benchmark schemes.

Hybrid modeling of an ultracentrifugation process for separation of full and empty adeno-associated virus particles

Ultracentrifugation is an attractive method for separating full and empty capsids, exploiting their density difference. Changes of the serotype/capsid, density of loading material, or the genetic information contained in the adeno-associated viruses (AAVs) require the adaptation of the harvesting parameters and the density gradient loaded onto the centrifuge. To streamline these adaptations, a mathematical model could support the design and testing of operating conditions.Here, hybrid models, which combine empirical functions with artificial neural networks, are proposed to describe the separation of full and empty capsids as a function of material and operational parameters, i.e., the harvest model. In addition, critical quality attributes are estimated by a quality model which is operating on top of the harvest model. The performance of these models was evaluated using test data and two additional blind runs. Also, a “what-if” analysis was conducted to investigate whether the models’ predictions align with expectations.It is concluded that the models are sufficiently accurate to support the design of operating conditions, though the accuracy and applicability of the models can further be increased by training them on more specific data with higher variability.

Evolution of dispersal and the analysis of a resource flourished population model with harvesting

This study explores a spatially distributed harvesting model that signifies the outcome of the competition of two species in a heterogeneous environment. The model is controlled by reaction-diffusion equations with resource-based diffusion strategies. Two different situations are maintained by the harvesting effects: when the harvesting rates are independent in space and do not exceed the intrinsic growth rate; and when they are proportional to the time-independent intrinsic growth rate. In particular, the competition between both species differs only by their corresponding migration strategy and harvesting intensity. We have computed the main results for the global existence of solutions that represent either coexistence or competitive exclusion of two competing species depending on the harvesting levels and different imposed diffusion strategies. We also established some estimates on harvesting efforts for which coexistence is apparent. Also, some numerical results are exhibited in one and two spatial dimensions, which shed some light on the ecological implementation of the model.

Numerical characterization of piezoelectric energy harvesting from an L-shaped frame

An L-shaped structure, intended for piezoelectric energy harvesting, is being characterized numerically to obtain extended insight into the effect of various parameters and metrics that are hard to track from experimental setups and simplified analytical models and to show the underlying mechanism of efficient piezoelectric harvesting. A numerical model was developed to analyze the structure under harmonic base excitation to obtain voltage frequency response and strain distribution data. The model takes into effect the load resistance applied between the piezoelectric patch electrodes and the damping ratio of each mode for accurate resonance amplitude evaluation. The validity of the model was confirmed by comparisons with previous experiments and showed strong agreement. The approach demonstrated that piezoelectric energy harvesting modeling, in general, is sensitive to inaccurate estimations, especially in the damping parameters, which emphasizes that rough assumptions made in analytical models will not yield results that can be discussed in correlation with experimental outcomes. This work states the guidelines for accurate piezoelectric modeling using numerical software, with the aim of enabling the investigation of complex harvesters, providing more insights to direct researchers to more proof and optimized designs that tackle broadband and energy density problems found in simple harvesters.

DESIGN FEATURES OF GRAIN HARVESTING COMBINEERS CASE IH "AXIAL-FLOW" SERIES

Harvesting grain is a very important production process that must be carried out as quickly as possible to obtain high-quality grain. Here it is important that the equipment is adjusted to the structure of the plants, and the plants, in turn, are prepared for machine harvesting. When creating grain harvesting equipment, various factors are taken into account: agrobiological properties and the structure of plant organs, stand height and density, lowness, strength, humidity, size and weight of fruits, weight ratio of grain to non-grain part, stage of maturity and others. Currently, harvesting of grain crops is carried out by direct or separate combining. Direct involves performing several operations: cutting plants, threshing plant mass, separating grain from straw, cleaning grain from various impurities, as well as harvesting grain and non-grain part of the crop. It is important that the harvester performs these processes at the same time in the stage of full maturity of the grain. This harvesting method is suitable for bread mass that is not clogged and has ripened evenly. As for separate combining, here mowing of plants and their threshing are carried out separately. Providing the enterprise with high-performance harvesters and the level of their use significantly affect the gross harvest of agricultural crops. In case of violation of the calendar terms for harvesting grain crops by more than 10–12 days, grain losses can reach 25–30%. In order for such a situation not to arise, agricultural enterprises must have the required number of harvesters of the necessary capacity, which could ensure, in the optimal time, harvesting of agricultural crops. In order to give preference to one or another combine harvester model, you need to know not only its price, but also individual technical and economic characteristics and the cost of threshing a ton of harvest. Because this indicator reflects the cost of the harvester, operating costs, its productivity, reliability and cost of spare parts. Innovation is only accelerating. Over the past 20 years, the average productivity of self-propelled grain harvesters has increased almost four to five times. The level of computerization of mechanized operating technologies also increased. The demand for products of the grain sub-complex is only growing. Ukraine is dominated by a diverse fleet of industrial grain harvesters of foreign production, purchased both new and used, the use of these grain transport systems is expedient and relevant. The question of choosing a modern high-performance grain harvester and the question of its effective use remain relevant.

Non Orthogonal Multiple Access (NOMA) Using a Nonlinear Energy Harvesting Model

This paper derives and optimizes the throughput of NOMA with nonlinear energy harvesting. The Base Station (BS) harvests energy from the received Radio Frequency signal. Then, the BS uses the nonlinear harvested power to diffuse packets to N users. We suggest to optimize harvesting time and the powers of users to optimize the data rate. The optimization of NOMA powers and the harvesting process were not yet performed with a non linear energy harvesting model. The study is performed for Rayleigh channels in the presence of nonlinear energy harvesting model. Furthermore, the theoretical results were confirmed using MATLAB computer simulations.

Coping Strategies to Address Water Scarcity through Local Knowledge in Tidal Flood and Erosion-Prone Areas: A Case Study of Timbulsloko, Sayung Regency, Demak Municipality

Access to clean water in Indonesian households remains relatively low due to insufficient clean water facilities and infrastructure. This research addresses the Sustainable Development Goal (SDG) of providing clean water, sanitation, and a clean environment (abbreviated as WASH) in sinkingcoastal areas vulnerable to tidal floods and erosion. PDAM and PAMSIMAS services struggle to function effectively in these regions. Despite government programs aimed at providing drinking water to impoverished communities, PDAM services often remain inaccessible to residents in subsiding coastal areas afflicted by floods, tides, and erosion. The residents of Hamlet Timbulsloko face a critical challenge in securing clean water and maintaining proper sanitation, exacerbated by submerged wellscaused by erosion. In their quest to meet this basic need, residents have adopted various coping strategies, including rainwater collection using buckets, basins, and even repurposed containers. Rainwater harvesting has become a community-driven solution to the unmet need for clean water, particularly when the cost of refill water is prohibitively high within the region. This research takes inspiration from the local knowledge and practices of residents and seeks to provide a rainwater harvesting model as a sustainable clean water solution

Performance Evaluation of Half-Feed Rice Combine Harvester

Rice (Oryza sativa) is one of the most important cereal grains cultivated in an area of 165 million hectares with approximately 756.7 million metric tons of production in the world. In 2019, Pakistan’s area under rice cultivation was about 2.9 million hectares, with 7.5 million tons yield. Rice-wheat cropping system is the most famous, especially in Punjab, Pakistan. Harvesting is presently conducted through manual labor or with the utilization of outdated models of combined harvesters with huge grain quality and quantity losses. Imported half-feed rice combine harvester was introduced and an experiment was planned to evaluate their feasibility. The performance was evaluated at three levels of forward speed (3, 4, and 5 km/h) and cutter bar heights (12, 16, and 20 cm) during the harvesting season of 2021 in the district Sheikhupura, Punjab. The machine performance was based on header loss, effective field capacity, broken grains percentage, fuel consumption, and field efficiency. The collected data was analyzed at a 5% level of probability by randomized complete block design (RCBD). The statistical analysis revealed that the machine performed better at the speed S2 (4 km/h) and cutter bar height H2 (16 cm) with the maximum EFC (0.55 ha/h) and Field Efficiency (75.3 %) as well as minimum Grain Losses (24.7 kg/ha) and Grain Breakage (14.2 kg/ha) in standing crop condition. Therefore, this machine is recommended to farmers due to its higher EFC and Field Efficiency as well as lower Grain Losses and Grain Breakage as compared to the conventional methods and obsolete machinery.

Predictive lumped model for a tunable bistable piezoelectric energy harvester architecture

In this article, we propose the modelling of a tunable bistable piezoelectric energy harvester (or BPEH) architecture. The latter is a type of ambient energy converter that continues to gain attention due to their wideband frequency response. As the non-linear dynamics of BPEHs imply significant modeling complexity, dynamic lumped models are necessary to predict BPEHs’ dynamic response and should fit the type of architecture studied. The BPEH architecture of interest uses post-buckled beams to create bistability and an amplified piezoelectric actuator (or APA) to convert the ambient vibrations. To date, no dynamic lumped models have been found in existing literature that account for both the electromechanical conversion and the dynamic behavior of buckled beams, with a specific focus on their axial and bending stiffness, for this BPEH architecture. Additionally, the proposed BPEH architecture offers buckling level tunability, which is achieved using an additional APA. Hence, the aim of this paper is to propose a new lumped model for a BPEH architecture that considers the effect of the post-buckled beams’ stiffness and of the additional APA through an elasticity factor κ― . This lumped model is established using Euler Lagrange equations and is experimentally validated on a tunable BPEH prototype. This validation shows an average relative error below 6% between the model predictions and experimental dynamic response of the prototype to an ascending frequency sweep, compared to an average relative error that is around 14% for the model proposed in literature. Moreover, numerical simulations using the proposed model lead to the conclusion that there is an optimal elasticity factor κ― that ensures the maximum power output while maintaining the frequency bandwidth.

Mathematical Analysis of the Electromotive Induced Force in a Magnetically Damped Suspension

This study explores the advanced mathematical modeling of electromagnetic energy harvesting in vehicle suspension systems, addressing the pressing need for sustainable transportation and improved energy efficiency. We focus on the complex challenge posed by the non-linear behavior of magnetic flux in relation to displacement, a critical aspect often overlooked in conventional approaches. Utilizing Taylor expansion and Fourier analysis, we dissect the intricate relationship between oscillation and electromagnetic damping, crucial for optimizing energy recovery. Our rigorous mathematical methodology enables the precise calculation of the average power per cycle and unit mass, providing a robust metric for evaluating the effectiveness of energy harvesting. Further, the study extends to the practical application in a combined system of passive and electromagnetic suspension, demonstrating the real-world viability of our theoretical findings. This research not only offers a comprehensive solution for enhancing vehicle efficiency through advanced suspension systems but also sets a precedent for the integration of complex mathematical techniques in solving real-world engineering challenges, contributing significantly to the future of energy-efficient automotive technologies. The cases reviewed in this article and listed as references are those commonly found in the literature.

Rainwater harvesting as a sustainable solution for the production of urban hydroponic crops

ABSTRACT Population growth and poor agricultural practices demand an improvement in the efficiency of food production. Urban hydroponic crops represent a potential solution to this challenge. However, the use of drinking water for urban agriculture is not a priority. Consequently, rainwater harvesting can reduce the use of drinking water for other purposes than human consumption. This study evaluated the efficiency of rainwater harvesting for the production of hydroponic crops in an Andean city. We developed a rainwater harvesting model to analyze the efficiency and optimization of two hydroponic production scenarios: (1) domestic production (30 plants) and (2) small-scale commercial production (200 plants). We found an efficiency of 99.71 and 75.79%, for scenarios 1 and 2, respectively. The 75.79% efficiency is given by the presence of low precipitation periods, which in the case of the study area are sporadic. Furthermore, scenario 2 could reach efficiencies of 100% if the roof capture area increases up to 40 m2. Rainwater harvesting in Andean cities, with sustained precipitation throughout the year, is enough to supply water for domestic and small-scale commercial hydroponic production with basic household modifications. We show promising results by combining rainwater harvesting and hydroponic crops for improving urban food and water security.

Robust transmission design for active IRS-aided multiuser MIMO cognitive radio systems with non-linear energy harvesting models

Robust transmission design for active IRS-aided multiuser MIMO cognitive radio systems with non-linear energy harvesting models

On the roles of strain gradient tensors in quasi‐3D nonlinear dynamics of microplate‐type piezoelectric systems of energy harvesting under triangular mechanical actuation

AbstractThe small‐scale‐dependent nonlinear dynamical attributes of microplate‐type laminated piezoelectric systems of harvesting energy subjected to a triangular mechanical actuation are explored in the current exploration. The core of harvesting systems is supposed to be made of nanocomposites reinforced by randomly oriented carbon nanotubes (CNTs) having various degrees of agglomeration coated by piezoelectric layers. In this regard, the microplate‐type systems of harvesting energy are modeled via a quasi‐3D plate theory combined with the modified strain gradient elasticity in the presence of various microsize‐dependent strain gradient tensors. Thereafter, the solution of the developed coupled electromechanical size‐dependent nonlinear problem is obtained numerically by utilizing the meshless collocation approach employing incorporation of the polynomial and radial basis functions to remove any feasible singularity for the associated moment matrices. It comes to the conclusion that by elevating the quantity of CNTs disclosed within the clusters, the significance of the microsize dependency in the achieved voltage enhances from 22.06% to 22.73% toward the simply supported bridge‐type context, and from 33.00% to 33.92% toward the clamped bridge‐type context.Highlights Development of a microstructural‐dependent quasi‐3D shear flexible energy harvester model. Incorporating the roles of various strain gradient tensors in the nonlinear dynamics of microharvesters. Size‐dependent time‐histories of achieved voltage from triangular mechanical‐loaded microharvesters. Influence of the CNT reinforcement clustering on the nonlinear dynamic performance.

Design and Modelling of Urban Stormwater Management and Treatment Infrastructure for Communities in Wuse, Abuja

Effective stormwater management can be used to regulate water quantity and quality for environmental sustainability, flood control, pollution reduction and other advantages of civil engineering infrastructures. Pollution of the environment and contamination of water sources can emanate from improper stormwater management. This study used a small-scale model of rainwater harvesting to analyze the design and model of urban stormwater management and treatment infrastructure for the neighborhoods in Abuja. The water quality of the treated stormwater retrieved has improved as a result of the usage of memory foam, alum, and chlorine to filter out contaminants and pathogens. With the fictitious stormwater treatment model created for this study, average values of the physicochemical parameters were collected from the stormwater discharge after it had been filtered and treated. The use of potash alum has had a variety of effects on the water’s quality. From 697 mg.L-1 to 635 mg.L-1, the total dissolved solids dropped. The DO dropped from 5.87 mg.L-1 to 3.92 mg.L-1 as well. Additionally, the turbidity rose from 4.42 FNU to 4.58 FNU, and the salinity rose from 0.7 PSU to 1.44 PSU, respectively. pH decreases from 19.78 to 15.17 mg.L-1, BOD decreases from 8.35 to 6.51, and COD decreases from 2.55 to 1.9. Calcium hardness has decreased from 287 mg.L-1 to 265.83 mg.L-1. The conductivity increases marginally from 3.24 ms.cm-1 to 3.82 ms.cm-1. The Fe2+ and Zn2+ ions exhibit a little decrease from 0.143 mg.L-1 to 0.055 mg.L-1 and from 0.092 mg.L-1 to 0.045 mg.L-1, respectively. Due to inadequate or nonexistent drainage systems in the many states and villages throughout the country, stormwater run-off management and treatment in Nigeria have been a colossal failure. Effective stormwater management can be sustained by using legal and environmental laws.

Occluded apples orientation estimator based on deep learning model for robotic harvesting

Apple harvesting robot is in rapid development in the recent years due to the shortage of manual labor. Robotics vision system has been one of the main focus in the development to achieve successful grasping. Information such as the apple orientation is valuable for developing more effective fruit detachment strategies. Occlusions in the orchard environment and the lack of distinct features in an apple has made it challenging to identify the apple orientation. Our study presents a novel approach that aims to estimate the orientation of fruits by projecting 2D information onto a 3D space. This method specifically targets the field of robotic harvesting and leverages multiple well-established and reliable fundamental methods currently available that includes keypoint detection neural network and circle detection based on extracted line segments of occluded apple. Based on the extracted information, a unit vector that represents orientation of the apple can be computed and transformed according to the relative position between the apple and the camera. The proposed method is evaluated using a publicly available 3D point cloud data of 11 apple trees from an orchard farm that was additionally labeled manually with apple orientations. To verify the evaluation results, the proposed method is tested by integrating it into an apple harvesting robot to perform inspection. Results shows that the median angular error in the orchard setting is 17.6° whilst in the lab setting is 14.6°. The experimental results show that the performance of the proposed method is comparable to existing research when under heavy occlusion and thus it is suitable for harvesting robot operating in the orchard farm.

Mathematical Modeling of Bird Harvesting in Intensive Poultry System

This work, presents a formulation of mathematical model of bird harvesting in an intensive poultry system, under the assumption that under a favourable environmental atmosphere and good management system, the birds have logistic growth. The model is analysed using methods from dynamical system theory and theory of calculus. It was established that the system has two steady state, the two equilibrium state are both locally asymptotically stable. The first one is stable if there is a bound on the harvest rate of the birds, which is proportional to the growth rate of the birds. The second equilibrium state is locally asymptotically stable (LAS) if k < \(\frac{r(C+y)}{p}\) that is if the carrying capacity is less than the ratio of the sum of and Per unit tax on the bird to that of Per unit price of the birds. Further analysis indicates that the limiting population of bird, that is the maximum population of birds that the available resources in the system can sustain and also ensures harvesting profitability is given as

An improved stochastic averaging process on a monostable piezoelectric vibrational energy harvester model excited by colored noise

A monostable piezoelectric vibration energy harvester (VEH) model subject to Gaussian colored noise is studied in this paper. With the help of energy balance method, a concise expression of the transient frequency which is determined by transient amplitude is used in the stochastic averaging process. Then an Itô stochastic differential equation is obtained. The new expression of frequency can lead to pretty good probability density function (PDF) of the displacement, PDF of output electric voltage of the VEH model, even if the nonlinear stiffness coefficient is very large. The influence of the nonlinear stiffness coefficient on the PDFs and on the output electric voltage is detailed and discussed. It is found that the larger nonlinear stiffness coefficient is, the smaller motion range and smaller mean square value of electric voltage it will result in. Furthermore, the larger time delay coefficient of the colored noise is, the larger mean square value of electric voltage it will lead to. Numerical simulations verified the accuracy of this method.

A new approach to the fractional Abel k−integral equations and linear fractional differential equations in a fuzzy environment

This paper introduces some recent approaches to the fuzzy fractional Abel integral equations with respect to another function, which is called the fuzzy fractional Abel k−integral equations. The problem proposed here allows for the interpolation of different types of fuzzy classical fractional Abel integral equations, and the solvability of each type of integral equation is also discussed. Additionally, a new approach to the linear fuzzy fractional differential equations in the space of generalized fuzzy functions is introduced. Unlike previous approaches with gH-differentiability, this approach avoids making any prior assumptions about the solution's monotonic behavior during the solving process. It also overcomes the problem of multiple solutions for fuzzy fractional differential equations. To demonstrate the benefits of this approach, two initial value problems of linear fuzzy differential equations are compared using two different concepts of fractional derivatives: the Caputo fractional gH-differentiability and the Caputo fractional derivative in the generalized fuzzy space. Furthermore, some applications are provided in a viscoelastic material model and a population growth with harvesting model.

A Robust Generator–Harvester for Independent Sensor Systems

The research is centered on energy production and harvesting to facilitate the transformation of electrical energy with energy-independent sensor systems, using powering devices in the expected power range of P = 10–10,000 W. A model application case for a harvester is the conversion of energy stored in the compressed gas during expansion; such gas embodies the energy stored in scenarios such as braking a car using an auxiliary pump. Similar systems find use in sensing various quantities in the transport sector (bridge structures, infrastructural components, cars, and other objects). The proposed theoretical harvester models describing the transformation of linear motion energy into electricity provide relevant support for the experiments. In the given context, the results obtained in the designing and construction of a robust motion generator with a primarily linear geometry-based system technology are presented, too. The expected output of electrical power of an N-segment harvester within the tested type is variable, and the design exploits the rectilinear motion generated by an engine using compressed air, a small fuel system, and similar options to obtain an expected/adjustable N-segment power in the range of Psm = 10–500 W. The fundamental structure of the generator core has been continuously numerically modeled, and an experimental setup has been developed to analyze the specific parts and variations in order to validate the concept and to achieve the most suitable parameters with the selected construction materials (a power yield increase of up to 2000 times). A scaled-down version of the model principle was tested in the experiments, and the parameters and results were compared with the predicted theoretical analyses. Generally, the conceptual layout of an enhanced magnetic circuit layout transforming motion energy into electricity was presented and verified.

Joint Trajectory and Resource Optimization for UAV-Assisted SWIPT Systems: A Comparative Study of Linear and Nonlinear Energy Harvesting Models

Joint Trajectory and Resource Optimization for UAV-Assisted SWIPT Systems: A Comparative Study of Linear and Nonlinear Energy Harvesting Models