Harvest Rates Research Articles

Oil-Grafted Track-Assisted Directional Transport of Water Droplets and Submerged Air Bubbles on Solid Surfaces

Wettability-tailored tracks are emerging as an efficient approach to collecting and transporting underwater air bubbles as well as water from the mist. However, tailoring the surface wettability by modifying the surface structural features via physiochemical methods to create superhydrophilic-superhydrophobic contrast tracks suffers from long-term durability issues, while the emerging liquid-infused slippery surface has inherent design engineering limitations and issues from infused oil depletion. Herein, we demonstrate that by selective silicone oil grafting onto the glass substrate, it is possible to create a wettability contrast of ∼ 43°. Further, we illustrate the application of such tracks for underwater air bubble capturing and transportation in an aqueous medium with surface tension ranging from 72 to 43.5 mN/m. In addition, the potential of these nonadhesive and adhesive tracks for water collection from the mist is shown and the critical effect of the track dimension and intertrack spacing on the water harvesting rate is investigated in detail. The study illustrates that the nonadhesive nature of the oil-grafted region enables the easy transport of underwater air bubbles as well as water from the flow medium and thus offers an easy and facile approach to creating substrates for underwater air bubble collection and water harvesting.

Design and Test of a Crawler-Type Tiger-Nut Combine Harvester

Traditional harvesters of tiger nuts (Cyperus esculentus) face problems including low harvesting efficiency, high loss rate, high impurity rate, and high labor intensity. To solve these problems and improve the harvesting efficiency and quality of tiger nuts, a crawler-type tiger-nut combine harvester that integrates digging, soil removal, picking, screening, and collection was designed. The machinery comprises crawler devices and working devices. The key devices were designed through theoretical analysis. Therein, the digging and hoisting devices consist of digger blades, combined soil-breaking blades, and vibrating hoisting chains. The tuber picking and screening device is composed of the tuber picking drum, double-deck heterodromous vibrating screens, impurity removal blowers, and soil-crushing guide rollers. The crawler devices include the track assemblies and the hydraulic driving systems. SolidWorks was used to establish the virtual prototype model. Combined with simulation using the discrete element software, the law of motion of tiger-nut tubers in the digging, elevation, and screening processes was studied, which verified the feasibility of the design. Finally, a prototype was manufactured and fabricated to conduct field harvesting tests on tiger nuts. Field test results indicate that the harvesting efficiency, harvest rate, and impurity rate of the tiger-nut harvester are separately 0.216 ha/h, 98.14%, and 3.24%, which meet the harvesting requirements for tiger-nut growers.

Dynamics of a coupled socio-environmental model: An application to global CO2 emissions

In this article, a novel coupled socio-environmental model is proposed and analysed using real data. The model is formulated with two interconnected subsystems: a human–environment model that describes the state of forest cover, human population, and atmospheric carbon dioxide (CO2) concentration; and a socio-economic model that represents human behaviour as a dynamical variable. Human behaviour focuses on their opinion about forest conservation, which affects the harvesting rate per unit area. We examine the mathematical model analytically and numerically to gain insight into the dynamics of the coupled system. By plotting the basin of attractions, we show that when an initial abundance of forest cover is small, and there is a low fraction of conservationists, the system eventually stays at a higher density of forest cover and a higher fraction of conservationists. However, for intermediate to high values of initial forest cover, the system stays at a low forest cover and a low fraction of conservationists among people. With an increase in the economic cost, after a certain threshold, we observe that the number of cooperators increases despite the forest cover being very low. Further, the model is validated using yearly data on forest cover and atmospheric CO2 in the period 1990–2016. The fitting to the data is performed using a MATLAB optimization technique, and the quality of the fitting is quantified using accuracy metrics. Numerical simulations using estimated parameters show that increasing forest cover is essential in reducing the CO2 level in the atmosphere. From a policy-making point of view, it is important to increase the proportion of conservationists in the community, which will eventually result in increased forest cover and consequently decrease the burden of atmospheric CO2 concentration.

Feasibility Study of Atmospheric Water Harvesting by Direct Cooling in Thailand

The objective of this work is to assess the potential of the atmospheric water harvesting (AWH) by direct cooling under the climate of Thailand. The assessment was considered from water scarcity, meteorological data and engineering analysis, including moisture harvesting index (MHI), water capability and energy cost. The meteorological data between 2012-2021 were used as primary data for engineering analysis. The results showed that Thailand has the potential to supply freshwater by using AWH with direct cooling. The average MHI of Thailand is 0.548 which is comparable with high potential of global assessment. 71 cities from 77 cities in Thailand have MHI over 0.50, which is the favorable condition for AWH by direct cooling. From the calculation under Thailand conditions, the water harvesting rates by direct cooling could be in the range of 0.97-1.30 L/h with energy costs as low as 0.047 USD/L for 71 cities in Thailand.

Pushing the Limit of Beetle‐Inspired Condensation on Biphilic Quasi‐Liquid Surfaces

AbstractMassive studies concern the development of low‐carbon water and energy systems. Specifically, surfaces with special wettability to promote vapor‐to‐liquid condensation have been widely studied, but current solutions suffer from poor heat transfer performances due to inefficient droplet removal. In this study, the limit of condensation on a beetle‐inspired biphilic quasi‐liquid surface (QLS) in a steam environment is pushed, which provides a heat flux 100 times higher than that in atmospheric condensation. Unlike the beetle‐inspired surfaces that have sticky hydrophilic domains, the biphilic QLS consists of PEGylated and siloxane polymers as hydrophilic and hydrophobic quasi‐liquid patterns with the contact angle hysteresis of 3° and 1°, respectively. More importantly, each hydrophilic slippery pattern behaves like a slippery bridge that accelerates droplet coalescence and removal. As a result, the condensed droplets grow rapidly and shed off. It is demonstrated that the biphilic‐striped QLS shows a 60% higher water harvesting rate in atmospheric condensation and a 170% higher heat transfer coefficient in steam condensation than the conventional beetle‐inspired surface. This study provides a new paradigm to push the limit of condensation heat transfer at a high heat flux, which sheds light on the next‐generation surface design for water and energy sustainability.

Analisis Model Mangsa Pemangsa dengan Adanya Penyakit dan Pemanenan pada Pemangsa

The interaction between two populations that are prey and predator can be described in a prey-predator model. In fact, in the interaction of prey and predators it can occur that when the density of prey is low, the effect of predation is also low, but if the size of the prey population increases, predation will be more intense which is stated in the Holling III Type response function model. In addition, it can also be found in an environment where there are populations of sick predator that result in death from the disease. This study aims to analyze the stability of the prey-predator model with the Holling III Type response function which consists of three subpopulations namely prey, healthy predator and sick predator. The analysis was carried out using the linearization method and then the type of stability was determined based on the characteristic eigenvalues obtained using the Routh-Hurwitz criteria. From this research it was found that population extinction is not possible while prey exists, extinction of diseased predator and populations exist is still possible if the required conditions are satisfy. Numerical simulations show that an increased harvesting rate in healthy predator populations results in a decrease in healthy predator populations, an increase in prey populations and a decrease in diseased predator populations. Meanwhile, a reduced harvesting rate for sick predator populations does not have a significant effect on the number of diseased predator populations, but results in an increase in the number of healthy predator populations and a decrease in prey populations

The calculation and choice of the electromagnet parameters for the grain and seeds disinfectant device

BACKGROUND: High infection rate of grain harvest, produced in Russia annually, by causative agents of fungal and bacterial diseases, causing significant quantitative losses of grain and decreasing of storage quality, revealed low efficiency of operation of chemical treatment, nowadays widely used in production for disinfection of grain and seeds. Therefore, development of electrophysical disinfection methods, which are environmentally friendly and effective against fungal and bacterial infections, as well as development of technical devices for their implementation is a relevant scientific and production problem.
 AIMS: Development of method of choice and definition of reasonable parameters of alternating current generator and electromagnet of disinfectant device for grain and seeds.
 METHODS: The study subjects are methods and conditions of generation of alternating magnetic fields in the operational volume of impact on grain seeds flow. The study method is analysis of laws of electromagnetism and adaptation of them to the process of definition of electromagnet parameters for the operational volume of the disinfectant device. The study materials include the adapted mathematical expressions of magnet winding parameters and the method of their use.
 RESULTS: For the sake of implementation of the new method of grain and seeds disinfection from causative agents of fungal and bacterial diseases by alternating magnet field, two methods of choice and calculation of electromagnet, which is the key element of the disinfectant device, have been developed. The first method comes to reasonable use of properties of a chosen generator by means of definition of coil winding parameters, ensuring demanded field density. Coil dimensions and time of impact on seeds will determine the device performance for treated grain. In the second method, the capacity of material flow through operational chamber (in the electromagnet) is conditioned by operational needs. It determines the size, parameters and operational modes of chamber (the inductance coil), ensuring the field demand, enough for disinfection, that, in the end, defines the properties of the generator.
 CONCLUSIONS: The suggested method makes it possible to accelerate the development of facilities for implementation of highly efficient, energy saving and environmentally friendly technology of low-frequency magnetic disinfection of grain and seeds and to incorporate it in agricultural production.

SILKBOT : Orchestrating Silk Symphony - A Comprehensive Approach towards Silk Production and Enhancement in Sericulture Applications

In this paper, the orchestrating of the silk symphony - a comprehensive approach towards silk production and enhancement in sericulture applications is presented. The final year project work undertaken by us involves the design & development of a silkbot, which will give us the comprehensive approach towards Silk Production and Enhancement in the quality of silk produced. The aim of the project is to revolutionize silk production through a comprehensive approach encompassing four critical components that are Segregation of cocoon based on gender, Identification of diseased cocoons to curb disease spread and enhance yield, maintenance of ideal temperature conditions for the enhanced growth of cocoons and Maintenance of optimal feeding conditions tailored to cocoon growth and needs. Cocoon Segregation System - Focuses on the segregation of cocoons based on their genders which will be ensuring optimal silk production and controlled environment for the female cocoon who produce more raw silk than male and prevent Disease Spread. Diseased Cocoon Identification - Aims to implement an automated system for the identification of diseased cocoons, mitigating the spread of diseases that can significantly impact yield and harvest rates. Temperature Control System - Emphasizes the maintenance of ideal temperature conditions for the enhanced growth of Silkworms, optimizing the quality and quantity of silk production. Optimized Feeding System -Tailored feeding based on the growth stages and nutritional needs of the Silkworms for optimal silk production. The work carried out is the seventh semester main-project by the students of Electronics & Communication Engineering under the guidance of the faculties supervision (guide).

Complex dynamics induced by harvesting rate and delay in a diffusive Leslie-Gower predator-prey model

<abstract><p>In this paper, under homogeneous Neumann boundary conditions, the complex dynamical behaviors of a diffusive Leslie-Gower predator-prey model with a ratio-dependent Holling type III functional response and nonlinear prey harvesting is carefully studied. By scrupulously analyzing and comprehending the distribution of the eigenvalues, the existence and stability (balance) of the extinction and coexistence equilibrium states are determined, and the bifurcations exhibited by the system are investigated by a mathematical analysis. Additionally, based on the theoretical analysis and numerical simulation, (Harvesting rate-induced, Delay-induced), Turing-Hopf bifurcations points are derived. Our results show that delay and nonlinear prey harvesting rates can create spatially inhomogeneous periodic solutions.</p></abstract>

Dynamical behavior of predator–prey model with non-smooth prey harvesting

The objective of the current paper is to investigate the dynamics of a new predator–prey model, where the prey species obeys the law of logistic growth and is subjected to a non-smooth switched harvest: when the density of the prey is below a switched value, the harvest has a linear rate. Otherwise, the harvesting rate is constant. The equilibria of the proposed system are described, and the boundedness of its solutions is examined. We discuss the existence of periodic solutions; we show the appearance of two limit cycles, an unstable inner limit cycle and a stable outer one. As the values of the model parameters vary, several kinds of bifurcation for the model are detected, such as transcritical, saddle–node, and Hopf bifurcations. Finally, some numerical examples of the model are performed to confirm the theoretical results obtained.

Advancing circular economy principles through wild black soldier flies

<abstract><p>Biowaste management poses a significant and widespread challenge. However, its consideration as a resource has led to the emergence of innovative and sustainable biowaste management techniques. One such promising solution is the use of black soldier flies (BSF) in biowaste treatment. This technique offers various advantages, such as the transformation of biowaste into versatile products that can be used in agriculture, horticulture, aquaculture, animal husbandry, pharmaceuticals and energy production. Despite significant research on different aspects of the BSF biowaste treatment system, none have explored the application of circular economy principles in low-income settings using naturally occurring BSF, i.e., free-range BSF. This article addresses the gap utilizing a mixed-method approach through a case study to achieve two objectives: the localization of the circular economy through co-production with a community group and the viable production of black soldier fly larvae (BSFL) and compost to meet the community's needs. Through collaboration, a successful circular economy was established as biowaste was transformed into products and safely reintroduced into the local biosphere. Performance indices used included BSFL nutritional composition, harvest rates and heavy metal absence.</p> <p>Through community involvement, circular economy principles were effectively implemented to redirect a retail market's fruit and vegetable waste from the landfill. The free-range open system produced 19.15 kg of BSFL, with 44.34% protein content, 20.6% crude fat and zero heavy metals. These outcomes align with existing research, indicating that a community-led open BSFL system can generate valuable products while fostering circular economy principles with minimal financial, technological, energy and water resources.</p> </abstract>

Feasibility and Potential of Reduced Port Surgery for Total Gastrectomy With Overlap Esophagojejunal Anastomosis Method.

Reduced port surgery (RPS) for gastric cancer has been frequently reported in distal gastrectomies but rarely in total gastrectomies. This study aimed to determine the feasibility of 3-port totally laparoscopic total gastrectomy (TLTG) with overlapping esophagojejunal (EJ) anastomosis. A total of 81 patients who underwent curative TLTG for gastric cancer (36 and 45 patients with 3-port and 5-port TLTG, respectively) were evaluated. All 3-port TLTG procedures were performed with the same method as 5-port TLTG, including EJ anastomosis with the intracorporeal overlap method using a linear stapler, except for the number of ports and assistants. Short-term outcomes, including the number of lymph nodes (LNs) harvested by station and postoperative complications, were analyzed retrospectively. Clinical characteristics were not significantly different among the groups, except that the 3-port TLTG group was younger and had a lower rate of pulmonary comorbidity. There were no cases of open conversion or additional port placement. All operative details and the number of harvested LNs did not differ between the groups, but the rate of suprapancreatic LN harvest was higher in the 3-port TLTG group. No significant differences were observed in the overall complication rates between the 2 groups. Three-port TLTG with overlapping EJ anastomoses using a linear stapler is a feasible RPS procedure for total gastrectomy to treat gastric cancer.

ПРЕДПОСЫЛКИ К УВЕЛИЧЕНИЮ ПРОИЗВОДСТВА РАПСА В РОССИИ И МИРЕ

The article examines the preсonditions for the formation of the modern Russian rapeseed market and shows the main historical stages in the development of the rapeseed market in Russia and the world. The characteristics of the main rapeseed producers in the world by acreage and gross yield are presented. The main advantages of rapeseed as a universal oilseed crop are considered. The characteristics of the main rapeseed regions of the Russian Federation in terms of sown areas, gross harvest and yield rate are presented. A forecast for the development of the rapeseed industry in the Russian Federation in the medium term is given.

Restorative diets: a methodological exploration comparing historical and contemporary salmon harvest rates

Restorative diets: a methodological exploration comparing historical and contemporary salmon harvest rates

Existence and exponential stability of periodic solutions of Nicholson-type systems with nonlinear density-dependent mortality and linear harvesting

In this work we study a Nicholson-type periodic system with variable delay, density-dependent mortality and linear harvesting rate. Using the topological degree and Lyapunov stability theories, we obtain sufficient conditions that allow us to demonstrate the existence of periodic solutions for the Nicholson-type system and, under suitable conditions, the uniqueness and local exponential stability of the periodic solution is established. We illustrate our results with an example and numerical simulations.

Growth Responses of the Perennial Grass, Phalaris Aquatica L., to Cutting Frequency and Influence on Secondary Metabolites and Antioxidant Activity

Highlights Defoliation initiates physiological recovery and chemical defense mechanisms in Phalaris aquatica. Under infrequent defoliation treatment, P. aquatica has high DM production. Defoliation severity on herbage regrowth was associated with variation of secondary metabolite content and antioxidant activity. Phalaris may be suited to conservation pasture systems; the interval between cuts is about six weeks to maximize rates of regrowth. Results indicate that Phalaris may be used as fodder crop to sustained production and food security. Abstract. Perennial grasses are the key to the economic and environmental sustainability of pastures for livestock, and in arid and semi-arid environments, they can provide multiple ecosystem services more effectively than production systems based on annual crops. The objective of this study was to evaluate the effect of different defoliation frequencies on forage production and nutritive value of the Phalaris aquatica L. variety Soukra under field conditions in Tunis, Tunisia, over a period of 12 weeks. We tested four defoliation frequencies: (1) severe, (2) moderate, (3) infrequent, and (4) control. The growth responses measured were plant tiller number (NT), dry matter production (DM), and relative leaf regrowth rate (RLR). DM under the severe and moderate defoliation frequencies was 7% and 41% less than under control defoliation, respectively. However, DM production under infrequent defoliation was 91% and 43% higher than under severe and moderate defoliation. The relative leaf regrowth rate was affected by defoliation frequency; the highest regrowth rate was under severe treatment. However, tillering of P. aquatica was reduced under the severe and moderate frequencies of defoliation. Under increased defoliation frequencies, concentrations of secondary metabolites significantly decreased; total polyphenol content, flavonoid content, and tannin contents were higher in control and infrequent than in moderate and severe treatments. Antioxidant activity also decreased significantly with defoliation compared to the control treatment. There were no significant differences (P > 0.05) in ABTS (3-ethylbenzothiazoline-6-sulfonic acid) among the defoliation frequencies. Pearson's r correlation and PCA (Principal component analysis) data revealed that growth parameters, secondary metabolites, and antioxidant activity have positive and negative correlations in distinguishing the control and defoliation treatments. Results indicate that P. aquatica management should target moderate harvest rates in the adoption of perennial grass forage production systems in Tunisia. Use of perennial grasses for forage production can contribute to sustained production, food security, and rural livelihoods, and move farming systems towards providing multiple economic, environmental, and social benefits. Keywords: ABTS, Defoliation frequency, DPPH, Flavonoids, Growth responses, Matter production, Perennial grasses, Phalaris, Polyphenols.

Machine Learning Prediction Based Adaptive Duty Cycle MAC Protocol for Solar Energy Harvesting Wireless Sensor Networks

The dynamic nature of energy harvesting rate, arising because of ever changing weather conditions, raises new concerns in energy harvesting based wireless sensor networks (EH-WSNs). Therefore, this drives the development of energy aware EH solutions. Formerly, many Medium Access Control (MAC) protocols have been developed for EH-WSNs. However, optimizing MAC protocol performance by incorporating predicted future energy intake is relatively new in EH-WSNs. Furthermore, existing MAC protocols do not fully harness the high harvested energy to perform aggressively despite the availability of sufficient energy resources. Therefore, a prediction-based adaptive duty cycle (PADC) MAC protocol has been proposed, called PADC-MAC, that incorporates current and future harvested energy information using the mathematical formulation to improve network performance. Furthermore, a machine learning model, namely nonlinear autoregressive (NAR) neural network, is employed that achieves good prediction accuracy under dynamic harvesting scenarios. As a result, it enables the receiver node to perform aggressively better when there is sufficient inflow of incoming harvesting energy. In addition, PADC-MAC uses a self-adaptation technique that reduces energy consumption. The performance of PADC-MAC is evaluated using GreenCastalia in terms of packet delay, network throughput, packet delivery ratio, energy consumption per bit, receiver energy consumption, and total network energy consumption using realistic harvesting data for 96 consecutive hours under dynamic solar harvesting conditions. The simulation results show that PADC-MAC provides lower average packet delay of the highest priority packets and all packets, energy consumption per bit, and total energy consumption by more than 10.7%, 7.8%, 81%, and 76.4%, respectively when compared to three state-of-the-art protocols for EH-WSNs.

Resource Allocation in Multi-Cluster Cognitive Radio Networks With Energy Harvesting for Hybrid Multi-Channel Access

Cognitive radio and energy harvesting techniques have been able to provide insight for solutions to the inefficiency in spectrum utilization and the effects of the limited storage capacity of energy batteries. Nevertheless, the requirement for interference constraint for primary user (PU) protection, the quality of service (QoS) requirements of the SUs, and the low power density of the ambient electromagnetic waves have restricted the performance of the radio frequency powered cognitive radio networks (RF-CRNs) in terms of the achievable data rate for specific energy budget or sufficient energy budget for target data rate. We are therefore motivated to investigate a radio frequency powered cognitive radio (RF-CR) with the capacity for improved achievable throughput and energy harvesting. Our model consists of multiple PUs and SUs coexisting in a practical overlapping clustered network. In each time frame for the adopted time division multiple access (TDMA) technique, SUs can exploit the multi-user benefit to harvest energy from both the PU and SUs transmissions for improved active probability. Therefore, taken into consideration the heterogeneity of each SUs in terms of their signal-to-noise (SNR), the energy harvesting rates and the inter- and intra-cluster interference, the problem is formulated into a fractional nonlinear optimization to determine the sensing duration, and power allocations that maximize the average energy efficiency of the RF-CRN subject, to constraints on energy causality, and PU protection. The performance of the proposed hybrid multi-channel access scheme is studied in terms of the trade-off between the total achievable throughput by the secondary users and the interference generated among others. Simulation results show that a trade-off exists between achieving optimal spectral efficiency and energy efficiency and, the optimal transmit power therefore depends on the primary design objective. Results equally show that the proposed hybrid multi-channel access scheme outperforms the existing scheme in literature.

Barriers to implementation of dynamic reference points in fisheries management

Fish populations are dynamic; their productivity depends on the environment, predator and prey interactions, and fisheries harvest rates. Failure to account for these factors in fisheries science and management can lead to a misestimation of stock dynamics and productivity, resulting in overexploitation or forgone fisheries yield. Using an online survey, we asked fisheries scientists, industry stakeholders, Indigenous partners, and non-governmental organizations whether changing ecosystem productivity was a problem in their experience, how often dynamic approaches to fisheries reference points have been adopted, what methods had been used, and what fisheries they had been applied to. Changing fisheries or ecosystem productivity was reported as an issue by 96% of respondents; however, 74% of respondents said they had never seen dynamic reference points implemented, 16% said in very few instances, while 10% said frequently. The most common barriers to implementation of dynamic approaches in fisheries management were institutional inertia and uncertainty about whether a change in productivity was lasting. We discuss trade-offs between fisheries management performance and stability.

Response of Indian mustard (Brassica juncea) to varying spacing and transplanting in north Gujarat region

A field experiment was conducted at Castor Mustard Research Station, Sardarkrushinagar Dantiwada Agricultural University, Sardarkrushinagar, Gujarat during the winter (rabi) season of 2020–21, to study the response of Indian mustard [Brassica juncea (L.) Czernj.] to different spacing and transplanting schedule in north Gujarat. The experiment was conducted in a split-plot design with 4 spacing in the main plots and 3 transplanting dates in the subplots, that were replicated 3 times. The maximum plant height at harvesting (189.18 cm) and crop-growth rate (11.69 g/plant/day) at 30–60 days after transplanting (DAT) were recorded with narrow spacing of 45 cm × 30 cm and higher dry-matter accumulation at 30 and 60 DAT (11.57 and 71.70 g/plant respectively) were recorded at 60 cm × 45 cm spacing. Indian mustard transplanted at 45 cm × 30 cm spacing recorded significantly higher seed yield (2,187.1 kg/ha), being statistically at par with spacing 45 cm × 45 cm spacing (2,070.4 kg/ha). In terms of seed yield, the crop transplanted on 10 November (2,142.7 kg/ha) outperformed the crop transplanted on 20 November (1,829.0 kg/ha), but it was statistically on a par with the crop transplanted on 31 October (1,996 kg/ha). The higher net returns (`61,227/ha), production efficiency (19.59 kg/ha/day) and economic efficiency (`548.5/ha/ day) were registered at 45 cm × 30 cm spacing. Significantly higher net return realization (`63,596/ha), production efficiency (19.13 kg/ha/day) and economic efficiency (`567.8 /ha/day) were noted under 10 November transplanting.