Conventional Harvesting Research Articles

A brief harvesting-freezing delay significantly alters the kidney metabolome and leads to false positive and negative results.

Abnormalities in distinct metabolic pathways have been associated with the pathogenesis and progression of many forms of kidney disease. Metabolomics analyses can be used to determine organ-specific metabolic fingerprints and, ideally, should represent the metabolic state of the organ at the exact moment the sample is harvested. However, conventional harvesting methods depend on posteuthanasia tissue harvest, which results in ischemia conditions and metabolome changes that could potentially introduce artifacts into the final studies. We recently optimized a modified clamp-freezing technique for rodent kidney harvesting and freezing, significantly reducing ischemia and freezing times and granting a closer snapshot of in vivo metabolism. In this study, we characterized and compared the metabolome of kidneys harvested using our modified approach versus traditional techniques to determine which metabolites are preferentially affected by a brief lapse of ischemia and freezing delay and which are more stable. We used Sprague-Dawley rats as a model of wild-type (WT) kidneys and PCK [polycystic kidney disease (PKD)] rats as a model of chronic kidney disease kidneys. Finally, we compared the metabolic profile of clamp-frozen and delayed WT and PKD kidneys to determine which metabolic changes are most likely observed in vivo in PKD and which could be subjected to false positive or negative results. Our data indicate that a short harvesting-freezing delay is sufficient to impart profound metabolic changes in WT and PKD kidneys, leading to false positive and negative differences when comparing these genotypes. In addition, we identified a group of metabolites that were more stable. Interestingly, while the delay had a similar effect between WT and PKD, there were notable differences. The data obtained indicate that the quick clamp-freezing technique for kidney metabolomics provides a more accurate interpretation of the in vivo metabolic changes associated with the disease state. NEW & NOTEWORTHY Our study shows that a brief harvesting-freezing delay associated with organ collection and freezing can significantly alter the kidney metabolic profile of both male and female wild-type and a genetic model of chronic kidney disease. Importantly, given that the effect of this delay differs among genotypes, it is not safe to assume that equally delaying harvesting-freezing in wild-type and polycystic kidney disease kidneys adequately controls this effect, ultimately leading to false positive and negative results among different renal diseases.

Enhanced Broadband Tri-Stable Energy Harvesting System by Adapting Potential Energy – Experimental Study

Abstract This paper presents the process optimization of some key parameters, such as the size of the air gap and distance between fixed neodymium magnets to enhance the vibration-based energy harvesting effect in the tri-stable energy harvesting systems and the improved tri-stable energy harvesting system being the proposed solution under weak excitation. In order to do it, firstly the distributed parameters model of the magnetic coupling energy harvesting system, including macro fiber composites of the 8514 P2 with a homogenous material in the piezoelectric fiber layer and nonlinear magnetic force, was determined. The performed numerical analysis of the conventional and the improved tri-stable energy harvesting system indicated that introducing an additional magnet to the tri-stable system leads to the shallowing of the depth of a potential well by decreasing the air gap between magnets and consequently generating higher power output and improving the effectiveness of the proposed improved tri-stable energy harvesting system. Experiments carried out on the laboratory stand allowed us to verify the numerical results as well as determine the optimal parameters of the magnetic coupling system. Due to it, the effectiveness of the proposed system versus the conventional tri-stable energy harvesting system is most enhanced.

Investigating the Synergistic Effect of Tillage System and Manure Application Rates on Selected Properties of Two Soil Types in Limpopo Province, South Africa

Sustainable agricultural practices are needed to find a solution to the problem of soil erosion and decreased soil quality. A study was conducted during the 2021/2022 and 2022/2023 cropping seasons to evaluate the synergistic effect of the tillage system (TS) and manure rates (MR) on selected soil properties at the University of Limpopo Experimental Farm (Syferkuil) and University of Venda Experimental Farm (UNIVEN). The experiment had a split plot design with three replications. The main plots used conventional (CON) and in-field rainwater harvesting (IRWH) tillage systems, while subplots used poultry and cattle manure at rates of 0, 20, and 35 t ha−1. Bulk density (BD), aggregate stability (AS), pH, total N, organic carbon (OC), available P, and exchangeable cations (Ca, Mg, and K) were determined. IRWH significantly increased AS in the 0–20 cm soil layer at Syferkuil. TS × MR interaction significantly influenced AS and total N in the 20–40 cm soil layer during the 2022/2023 season at Syferkuil. IRWH significantly increased Mg content in the 2021/2022 season and total N, OC, and Mg content in the 2022/2023 season at Syferkuil over CON. At UNIVEN, CON significantly increased total N, whereas IRWH increased available P in the 2022/2023 season. MR significantly increased AS, exchangeable Ca, Mg, and K at both sites. At Syferkuil, MR significantly increased total N, OC, and available P during both seasons, whereas at UNIVEN the significant increase was observed on OC and available P during both seasons and total N in the 2021/2022 season. It was found that IRWH and poultry manure (35 t ha−1) improved most soil properties at both sites; however, this study recommends long-term experiments to investigate the combined effect of IRWH and manure rate on soil properties to validate the findings observed in this study.

A Pilot Study Showing Application of Palatal Bone Harvesting Under Dynamic Navigation Guidance in Oral Implantology.

In cases of insufficient bone volume in the implant area, bone augmentation surgery is often required to ensure an adequate amount of bone around the implant. In autologous bone grafting procedures, some patients face insufficient bone volume at conventional intraoral bone harvesting sites. Due to the high difficulty associated with completing palatal osteotomies freehand, fewer palatal lateral osteotomies have been reported, and palatal bone blocks are not routinely used in bone augmentation procedures. With the development of digitally guided implant technology, palatal bone harvesting has become feasible. In this paper, we will present a method of obtaining a circumferential bone block of the palate for implant surgical application through dynamic navigation guidance. A total of three patients had undergone this procedure to obtain circumferential palatal bone blocks and completed bone augmentation surgery. The bone augmentation results in the implanted area have been favorable, and there has been some bone recovery at the harvesting site. This is a safe and effective way to obtain intraoral bone blocks.

Preparation of vascularized forearm dermal fat flap and repairing of donor site

Objective:This study prepared vascularized dermal fat flaps and introduced a local split-thickness skin graft from an in situ cutaneous area cutaneous area to manage forearm flap donor sites and evaluated the esthetic and functional outcomes post-operatively. From July 2020 to June 2023, 13 patients with soft tissue defects in Oral and Maxillary Area were repaired with tvascular forearm dermal fat flap. There were 8 males and 5 females, aged from 42-71 years. The flaps ranged from 8 cm×7 cm to 7 cm×5 cm in size. The donor site defects were covered by local split-thickness skin graft from the in situ skins. The color matching degree, surgical scars, ranges of wrist movement and hand sensations in donor forearms were assessed at 6 months after surgery. Results:The tvascular forearm dermal fat flaps for 15 cases all survived. All the local split-thickness skin grafts transplanted with this technique showed primary healing. The follow-up period for 6 months, Donor site exhibited suitabler color matching and there was not severe complications. Conclusion:The vascularized dermal fat flap provides an alternative to conventional forearm flap harvest, which enables primary donor site closure with reduced rates of delayed donor site healing. The vascularized dermal fat flap is a relatively reliable repair method for soft defects in Oral and Maxillary Area.

Driving Wi-Fi IoT Sensors by a Hybrid Magneto-Mechano-Electric Energy Generator Extracting a Power of over 50mW.

Energy harvesting technology is mainly used as a power source for driving Internet of Things (IoT) devices. However, the output power of conventional harvesting devices are limited, suitable only for low-power-consumption IoT sensors based on Bluetooth communication. In contrast to Bluetooth, wireless fidelity (Wi-Fi) communication offers superior real-time monitoring and transmission capabilities, but requires more power in the range of hundreds of milliwatts or higher. Therefore, the hybridization of three energy conversion devices, namely, piezoelectric magneto-mechano-electric (MME) generator, electromagnetic (EM) induction coil, and triboelectric nanogenerator (TENG) is proposed as a standalone power source for Wi-Fi communication sensors. By integrating these three mechanisms, the hybrid MME energy harvester can achieve an output power exceeding 50mW at the second harmonic resonance condition under the alternating current (AC) magnetic field of 10Oe. Furthermore, it can successfully drive the Wi-Fi sensor, enabling continuous real-time monitoring without the degradation of charged power in a supercapacitor. These results highlight that energy harvesting technology is not limited to low-power devices but can also be applied to Wi-Fi communication sensors and beyond.

Underwater blade-free triboelectric nanogenerator for harvesting current energy in low-speed current

Ocean current energy bears the characteristics of wide distribution and high energy density. Harvesting current energy as the in-situ power for distributed ocean sensors will greatly enhance the sustainability of ocean sensing. In many parts of the ocean, the current speed is not desirable (low or unstable) for conventional current energy harvesting devices. Here, an underwater blade-free triboelectric nanogenerator (UBF-TENG) is developed to effectively utilize the low-speed currents through the flow-induced vibration (FIV). The power generation unit is fully enclosed inside the shell, effectively reducing the direct impact and underwater corrosion. The study demonstrates that within the established experimental parameters space, the optimized UBF-TENG can facilitate a start-up speed as low as 0.14 m/s. The UBF-TENG has achieved a maximum open-circuit voltage output of 250 V and a maximum short-circuit current output of 2.2μA at 0.76 m/s. The charging capacity of the UBF-TENG is tested with various capacitors, demonstrating the application potential of the UBF-TENG as an in-situ power supply underwater.

Non-toxic Bi2S3 quantum dot-sensitized TiO2 electrodes for cost-efficient solar power conversion

Inorganic light harvesting materials are revolutionising the current research scope of quantum dot-sensitized solar cells (QDSSCs) day by day. However, it is challenging due to the issues in toxicity and stability of existing light-harvesting materials. Herein, we present highly stable non-toxic bismuth trisulfide (Bi2S3) QDSSCs with iodide/triiodide redox electrolyte. The solar cell is configured as FTO/TiO2 P90/TiO2 P25/Bi2S3/(I-/I-3) electrolyte/Pt. Bi2S3 quantum dots (QDs) were fabricated onto the FTO/TiO2 P90/TiO2 P25 electrode at room temperature using the dip-successive ionic layer adsorption reaction (Dip-SILAR), which is an easy and efficient technique. Electron microscopy confirmed that the quantum dots formed uniformly on the photoanode, with sizes ranging from 50 nm to 80 nm. QDSSCs with an active cell area of 0.16 cm2 were characterized under an illumination of 100 mW cm-2 with AM 1.5 spectral filter and the results depicted that the best cell acquired a power conversion efficiency of 0.26 % with an open circuit voltage (Voc) of 482.9 mV and short circuit current density (Jsc) of 1.05 mA cm-2. To enhance the stability, polyvinylpyrrolidone (PVP) based gel polymer electrolyte has been used. The high cost of conventional light harvesting materials may be significantly reduced by one-step fabrication of Bi2S3 using the SILAR technique.

U shaped costal cartilage resection to reduce donor site morbidity

ObjectiveThe aim of our study is to reduce the complications of pain and chest wall deformity by modifying conventional costal cartilage graft harvesting. MethodIn this method while the superior part of the costal cartilage is removed completely, medial, lateral, and inferior parts are excised incompletely and used as a graft. Hence, continuity of the costal cartilage is maintained inferiorly. ResultsNineteen primary and 28 revision rhinoplasty patients were included in the study. There were no donor site complications in the early postoperative period or during one-year follow-up. ConclusionThe modified costal cartilage graft harvesting technique we described is a safe conservative surgical method.

Theoretical and experiment optimization research of a frequency up-converted piezoelectric energy harvester based on impact and magnetic force

Harvesting environmental vibrations to power electronic components is an essential approach for addressing the power supply challenge in MEMS. However, conventional vibration energy harvesting systems frequently suffer from limited frequency bandwidth and high-frequency deficiencies. This paper proposes a novel up-frequency structure for piezoelectric vibration energy harvesting (VEH) that relies on both nonlinear magnetic force and piecewise linear force. The proposed VEH’s nonlinear dynamic characteristics are analyzed theoretically, and an experimental prototype machining and vibration test platform are constructed. Theoretical and experimental results are compared and analyzed by conducting basic experiments and key parameter optimization experiments. The research results demonstrate that the proposed VEH can efficiently harvest vibration energy in low-frequency and wide-band environments. Regarding the system parameters, higher vibration acceleration results in increased output voltage and wider working frequency bandwidth. Reducing the gap distance enhances piecewise linear vibration, which broadens the working frequency bandwidth. Furthermore, the proposed VEH’s ability to harvest low-frequency vibrations can be enhanced by reducing the magnet distance, thereby reducing the linear resonance frequency of the system. The findings of this study offer valuable insights for advancing the engineering application of MEMS self-power supply technology.

Stem recovery and harvesting productivity of two different harvesting systems in final felling of Pinus patula

ABSTRACT With the current demand of wood products and industrial requirements, plantation owners need to re-think ways in which harvesting is carried out and identify the most efficient harvesting system that also utilizes small diameter parts of stem per industry’s product specifications. This paper contributes to the discussion by comparing the harvesting productivity and stem recovery between conventional harvesting (CH) and integrated harvesting (IH) systems. CH is harvesting which does not necessarily align with the log dimensional requirements of the customer and only recovers logs with big diameters while IH is based on harvesting and sorting logs according to need in a single operation so that as much volume and value as possible of the stands is realized. The study was carried out at the Sao Hill Forest Plantation in the Southern Highlands of Tanzania. The harvested compartment was purposively selected and divided into IH and CH plots. A total of 39 trees were randomly selected to be harvested from each plot. The findings portray a significant difference in the stem recovery of 75% for IH and 60% for CH. CH had an average cutting productivity of 16 m3/h as compared to 14 m3/h for IH while skidding productivity was 15.3 m3/h and 24.9 m3/h for IH and CH, respectively. In this study, the IH system resulted in higher production in terms of volume recovered, meaning IH had a significant impact on the production and stem recovery of the standard stem-wood for use in different industries.

Feasibility Study of Aquawall - An Alternative for Conventional Rain Water Harvesting System

Rainwater harvesting has been an age-old activity, practiced by many cultures in areas of poverty and wealth, but unfortunately our urban communities discard using it due to ignorance and lack of education. The challenge is to change the attitude of the state agencies responsible for environmental policy to make population being part of water saving, reduction of vulnerability and adaptation to climate change with rainwater harvesting. In our urban space limitations make it necessary to propose a system of “vertical water tank” that fulfills this function. The Aquawall project is based on the appropriate technology and the circular economy, made by self and is designed in a modular way, taking up minimal space, made of nine towers of six three-liter bottles each, connected to a PVC base

Halide perovskite photovoltaics for in-sensor reservoir computing

As intelligent electronics get laden with multimodal sensors, the data transfer and computation increase their energy expenditure. Consequently, researchers aim to develop efficient computing paradigms or integrate energy harvesting from ambient sources. Halide perovskites possess unique photophysics and coupled ionic-electronic dynamics that actualise memory devices for brain-inspired computing. Synergising the computing capability with their conventional light harvesting efficacy could aptly address the aforementioned problem. In a novel approach, the transient open circuit voltage (VOC) of a methylammonium lead bromide-based solar cell was exploited to serve as a self-powered volatile short-term memory for optoelectronic in-sensor reservoir computing. The origin of the memory is attributed to the influence of mobile ions on the carrier generation and recombination in the device. The system's versatility and task specificity were shown by engineering the volatility of the memory. The benchmarking task of MNIST handwritten digit recognition was performed with the highly reproducible and robust transformation of optical inputs into unique reservoir states. To demonstrate the high nonlinearity, second-order time-series prediction (NARMA2) was performed. Finally, an exemplary cardiac health-monitoring application was showcased by monolithic reading and processing of a physiological time series known as photoplethysmography (PPG) to identify atrial fibrillation with increased computational efficiency.

Postharvest evaluations of soil erosion, ground cover, and best management practice implementation on integrated biomass and conventional clearcut harvest sites

As demand for wood energy rises, it’s vital to understand the environmental impact of various harvest types, considering different best management practices (BMPs) and site conditions, for sustainable forest management. This study provides a comparative analysis of postharvest site characteristics between biomass and conventional harvest sites located in the Coastal Plain region of the southeastern US. A total of 30 recently harvest sites (15 each for biomass and conventional) were selected from the Coastal regions of Alabama, Georgia, and Florida. Erosion rates were estimated using the USLE-Forest method and ground cover was assessed as a percentage of the area covered by bare soil, litter, light slash, heavy slash, and piles. BMP implementation (%) was based on state-specific BMP surveys. The findings show that stream management zones (SMZs) and harvest areas were less prone to soil erosion, while forest roads, skid trails, and stream crossings were more prone to erosion, regardless of the harvest type. Conventional harvest sites had an overall weighted average erosion rate of 0.35 Mg/ha/year, with an average BMP implementation of 92.70 %, while biomass harvest sites had an overall weighted average erosion rate of 0.22 Mg/ha/year, with an average BMP implementation rate of 97.91 %. Average erosion rate (Mg/ha/year) from the harvest area (biomass=0.11, conventional=0.06) and SMZs (biomass=0.05, conventional=0.02) were not significantly different (p>0.05). Conversely, average erosion rate from roads (biomass=4.17, conventional=6.44), skid trails (biomass=2.15, conventional=3.73), decks (biomass=0.39, conventional=0.72), and stream crossings (biomass=1.53, conventional=5.31) were significantly higher in conventional harvest sites (p<0.05). BMP implementation rates for roads (biomass=98.09 %, conventional=93.71 %), stream crossings (biomass=95 %, conventional=71 %), and timber harvest (biomass=96.44 %, conventional=93.33 %) were significantly higher in biomass harvest sites, while waste management BMP (biomass=89.91 %, conventional=100 %) was significantly higher in conventional harvest sites. Regarding ground cover, conventional harvest sites had significantly larger areas covered by light slash, heavy slash, and piles than biomass harvest sites, while biomass harvest sites had significantly larger areas covered by green growth. Our research shows a significant negative correlation between overall BMP implementation and erosion rates (r=-0.67, p=0.0002), as well as site size (r=-0.38 p=0.0400), indicating that larger sites tend to have lower BMP implementation and increased erosion risk. In conclusion, biomass harvest sites in our study did not yield higher erosion rates in comparison to conventional harvest sites, provided that the current BMP recommendations were implemented properly and in adequate amounts. This study emphasizes the importance of site-specific management strategies to mitigate erosion in all harvest sites, irrespective of harvest type used.

Higher rates of anatomical insertion of medial hamstring tendon regeneration post-anterior cruciate ligament reconstruction with stump preservation graft harvesting technique: A prospective, randomised, double-blinded clinical trial with magnetic resonance imaging evaluation

Objective(s)The purpose of this study was to compare the regeneration of semitendinosus and gracilis tendons from two different graft harvesting techniques, which are the stump preservation and conventional graft harvesting techniques. We hypothesised that the stump preservation graft harvesting technique, which preserved the distal attachment of tendons at their insertion, would facilitate anatomical regeneration to the pes anserinus. MethodsThis is a prospective, randomised, double-blinded study whereby thirty consecutive patients who underwent single bundle anterior cruciate ligament reconstruction with ipsilateral semitendinosus and gracilis autografts were recruited. The patients were randomly assigned to the stump preservation group (14 patients) or conventional group (16 patients). Magnetic resonance imaging (MRI) evaluation was performed preoperatively and at six months post-operatively. ResultsAt 6-month follow-up, MRI evaluations showed a higher percentage of insertion of regenerated semitendinosus and gracilis at the pes anserinus in the stump preservation group (75.0%) than that in the conventional group (68.8%). There was a significantly higher proximal shift of the musculotendinous junction of semitendinosus (5.70 ​cm versus 3.36 ​cm, p ​= ​0.029) and gracilis (5.28 ​cm versus 3.16 ​cm, p ​= ​0.045) in the conventional group post-operatively. ConclusionThe stump preservation technique yields a higher percentage of anatomical insertion of regenerated tendons and a lesser amount of proximal shift of the musculotendinous junction. Level of EvidenceIII – Prospective study with up to two negative criteria.

Sunflower Growth and Grain Yield under Different Tillage Systems and Sources of Organic Manure on Contrasting Soil Types in Limpopo Province of South Africa

A field study was conducted to assess the effect of tillage systems (TSs) and manure rates (MRs) on sunflower growth and yield at the University of Limpopo Experimental Farm (Syferkuil) which is on sandy loam soils and University of Venda Experimental Farm (UNIVEN) clayey soils, both located in Limpopo Province of South Africa for 2021/2022 and 2022/2023 cropping seasons. The experimental design was a split plot with three replications. The main plot was the tillage treatments: conventional (CON) and in-field rainwater harvesting (IRWH), while the subplots were the manure treatments: viz. poultry and cattle manures at rates of 20 and 35 t ha−10, plus a control (no manure application). The IRWH is a tillage technique that collects rainwater on a 2 m wide runoff strip into the 1 m wide basin where it infiltrates deep into the soil beyond the evaporation zone but is available for crop use. The results revealed that at Syferkuil IRWH had a significant increase (p &lt; 0.05) on grain yield, head diameter, head dry matter and aboveground dry matter yield in both cropping seasons, whereas at UNIVEN, the significant increase was obtained on grain yield, head diameter, aboveground dry matter, plant height and stem girth during both cropping seasons. The effect of manure rate significantly increased with the application rate, with poultry manure at the highest rate of 35 t ha−1 significantly recording high mean values of grain yield, head diameter, head dry matter, aboveground dry matter, plant height and stem girth at both sites during the two cropping seasons. The increase in leaf area index and 100 seed weight by IRWH and manure rate application varied across the growing stages and cropping seasons with no consistent trend. At Syferkuil, TS and MR interaction was significant on head diameter and on aboveground dry matter at flowering stage in the first cropping season, whereas at UNIVEN, it was significant on head diameter in the first cropping season. Therefore, these results suggest that IRWH combined with poultry manure (35 t ha−1) can be adopted to improve sunflower crop yield under similar management and environmental conditions. In the absence of poultry manure, farmers may opt to use cattle manure at a rate of 35 t ha−1 for better improved yield.

Improving Tenebrio molitor Growth and Nutritional Value through Vegetable Waste Supplementation.

Huge amounts of vegetable wastes are generated by the food industry. Their bioconversion into valuable products (e.g., insect flours or biofertilizer) through insect farming is a promising solution to reduce their negative environmental and economic impacts. This study evaluates the growth of Tenebrio molitor larvae and their nutritional profile after supplementing their diets with vegetable wastes. Over a 6-week period, 45-day larvae were fed a diet comprising wheat bran supplemented (1:1) with cucumber or tomato wastes from both conventional and ecological crops. The control diet consisted of wheat bran and an equivalent amount of water to compensate for the waste moisture. Larval weight was measured weekly, and length measures were taken fortnightly. Nutritional composition and fatty acid profile were analyzed at the end of the study in 90-day larvae. Regardless of using vegetable waste from conventional or ecological harvesting, the weight of 6-week supplemented larvae almost doubled that of larvae fed with just wheat bran, and their length was 15% higher. Supplementation also increased larval polyunsaturated fatty acid percentage by 22-37%, with linoleic acid being the most abundant. Likewise, larval protein content reached 50% after supplementation. This study demonstrates that both cucumber and tomato wastes from conventional or ecological crops are excellent supplements for T. molitor's diet, improving their nutritional value and reducing the time necessary for larvae growth.

Comparison of conventional unstained lymph nodal harvesting vs methylene blue–stained lymph nodal harvesting in colorectal specimen in staging left-sided colorectal carcinoma: a randomized controlled trial

The management and prognosis of colorectal carcinomas (CRCs) are related to the stage of the disease, which, in turn, relies on the lymph node harvest from the surgical specimen. The guidelines recommend that at least 12 lymph nodes are required, which is not achieved in most resections. In this study, we propose a method to improve the lymph node yield in such cases. This study aimed to determine whether ex vivo injection of methylene blue into the inferior mesenteric artery or its branches improves lymph node retrieval in left-sided CRCs. This study was conducted as a single-center, double-blinded, superiority randomized controlled trial. Patients who underwent elective surgery for left-sided CRCs with curative intent were randomized into 2 groups: stained and unstained. The sample size was calculated as 66. In all patients, details of disease stage, history of neoadjuvant therapy, and number of isolated lymph nodes were recorded. The mean number of lymph nodes extracted from the stained group was significantly higher than that from the unstained group (15.9±5.2 vs 9.1±5.7, respectively; P<.001). Among the patients who had received neoadjuvant therapy, the yield was higher in the stained group (P<.001). The yield was found to be greater in patients who had undergone upfront surgery than in those who had undergone neoadjuvant therapy, even in the stained group (100% vs 66.7%, respectively). The use of methylene blue injection into resected specimens of left-sided CRCs significantly improved the lymph node yield.

Analysis of a Wind-Driven Power Generation System with Root Slapping Mechanism

This study introduces a groundbreaking slap-type Vibration Energy Harvesting (VEH) system, leveraging a rotating shaft with magnets to induce vibrations in an adjacent elastic steel sheet through magnetic repulsion. This unique design causes the elastic sheet to vibrate, initiating the oscillation of a seesaw-type rigid plate lever. The lever then slaps a piezoelectric patch (PZT) at the elastic steel sheet’s root, converting vibrations into electrical energy. Notably, the design enables the PZT to withstand deformation and flapping forces simultaneously, enhancing power conversion efficiency. The driving force for the rotating shaft is harnessed from the downstream flow field generated by moving objects like rotorcraft, fixed-wing aircraft, motorcycles, and bicycles. Beyond conventional vibration energy harvesting, this design taps into additional electric energy generated by the PZT’s slapping force. This study includes mathematical modeling of nonlinear elastic beams, utilizing the Method of Multiple Scales (MOMS) for in-depth vibration mode analysis. Experimental validation ensures the convergence of theory and practice, confirming the feasibility and superior voltage generation efficiency of this slap-type VEH concept compared to traditional VEH systems.

Performance test of the combine harvester machine for rice harvesting in Indrapuri, Aceh Besar District

Paddy is a very important agricultural crop for mankind because more than half of the world’s population and almost the entire population of Indonesia depend on this plant as a source of food. Harvesting is a very important process in rice production, because in this process it is alleged that the level of yield loss is very high. Paddy harvesting can be done by modern farming (combine harvester) and conventional (manual), therefore it is necessary to know the effectiveness by analyzing the performance and efficiency of the two ways. This study aims to examine the performance of rice harvesting using a combine harvester and conventional machines in Indrapuri District, Aceh Besar District. The results of the combine harvester research show that the theoretical field capacity is 0.42 ha/hour, the effective field capacity is 0.25 ha/hour, efficiency is 60.03%, the working capacity is 743.54 kg/hour, the fuel consumption is 10.25 L/hour, and yield loss of 1.31%. Conventional harvesting shows a field capacity of 0.0049 ha/hour/person, thresher working capacity of 172.6908 kg/hour, thresher efficiency of 98.5417%, thresher fuel consumption of 0.5147 L/hour, and the percentage of yield loss is 3.8776%. Based on data on harvesting capacity, the combine harvester shows a better performance then conventional harvesting.