Breaking Rate Research Articles

Neuromorphic compliant control facilitates human-prosthetic performance for hand grasp functions

Abstract Current bionic hands lack the ability of fine force manipulation for grasping fragile objects due to missing human neuromuscular compliance in control. This incompatibility between prosthetic devices and the sensorimotor system has resulted in a high abandonment rate of hand prostheses. To tackle this challenge, we employed a neuromorphic modeling approach, biorealistic control, to regain human-like grasping ability. The biorealistic control restored muscle force regulation and stiffness adaptation using neuromorphic modeling of the neuromuscular reflex units, which was capable of real-time computing of model outputs. We evaluated the dexterity of the biorealistic control with a set of delicate grasp tasks that simulated varying challenging scenarios of grasping fragile objects in daily activities of life, including the Box and Block Task, the Glass Box Task, and the Potato Chip Task. The performance of the biorealistic control was compared with that of proportional control.
Results indicated that the biorealistic control with the compliance of the neuromuscular reflex units significantly outperformed the proportional control with more efficient grip forces, higher success rates, fewer break and drop rates. Post-task survey questionnaires revealed that the biorealistic control reduced subjective burdens of task difficulty and improved subjective confidence in control performance significantly. The outcome of the evaluation confirmed that the biorealistic control could achieve superior abilities in fine, accurate, and efficient grasp control for prosthetic users.

Enhancing yield attributes in rainfed upland rice through incorporation of 6-benzylaminopurine in the cultivation program

This experiment was carried out to evaluate the response of two upland rice varieties to incorporation of 6-benzylaminopurine (6-BAP) into the traditional fertilizer program. Treatments were laid out in a randomized complete block design (RCBD) in 2 x 5 x 2 factorial including 2 upland rice varieties (NERICA 3 (N3) and NERICA 8 (N8)), 5 treatments notably T0 = Controls (NPK 20:10:10 and Urea 46%), T1 = 6-BAP (25mg/l), T2 = 6-BAP (50mg/l), T3 = 6-BAP (75mg/l) and T4 = 6-BAP (100mg/l) all repeated twice. All the treatments received NPK (20:10:10) + Urea 46% while application of T1 to T4 started at the flag leaf stage and was done in 3 splits of foliar sprays. The results revealed that 6-BAP significantly influenced mean number of stay green tillers/m2 at 120 days after transplanting with corresponding scores of 16, 87.5, 111, 110 and 127 for T0, T1, T2, T3 and T4 in Nerica 3. Maximum paddy yield in N3 were 8.37 and 4.49 t/ha respectively for T3 and T0 while in N8, paddy yields were 7.36 and 4.6 t/ha correspondingly for T4 and T0. In N3, broken grains rate after milling was 34.45 and 26.30 % individually for the control and T3 while in N8 grain breaking rate of 28.81 and 25.16 % were respectively scored by T0 and T3. This study reveals that, foliar spray of 6-benzylaminopurine at 75 mg/l in three splits of 7 days during flag leaf stage optimizes upland NERICA yields and grain morphological characteristics after milling.

Impact of near continuous low dose rate neutron irradiation on pregnancy outcomes in mice

The effects of galactic cosmic radiation on reproductive physiology remain largely unknown. We determined the impact of near-continuous low-dose-rate Californium-252 neutron irradiation (1 mGy/day) as a space-relevant analog on litter size and number of resorptions at embryonic day (E) 12.5 (n = 19 radiated dams, n = 20 controls) and litter size, number of resorptions, fetal growth, and placental signaling and transcriptome (RNA sequencing) at E18.5 (n = 21 radiated dams, n = 20 controls) in pregnant mice. A significantly increased early resorption rate and decreased placental weight were observed in irradiated mice. There were no statistically significant differences in litter size, fetal weight, length, or malformation rate between the groups. Near-continuous radiation had no significant effects on the mechanistic target of rapamycin (mTOR), endoplasmic reticulum stress or inflammatory signaling, rate of double-stranded DNA breaks, and had minimal effects on gene expression in the placenta. These data suggest that near-continuous, low-level galactic cosmic radiation has a limited impact on pregnancy outcomes.

Darcy–Forchheimer gravity currents in porous media

We theoretically and experimentally study gravity currents of a Newtonian fluid advancing in a two-dimensional, infinite and saturated porous domain over a horizontal impermeable bed. The driving force is due to the density difference between the denser flowing fluid and the lighter, immobile ambient fluid. The current is taken to be in the Darcy–Forchheimer regime, where a term quadratic in the seepage velocity accounts for inertial contributions to the resistance. The volume of fluid of the current varies as a function of time as $\sim T^{\gamma }$ , where the exponent parameterizes the case of constant volume subject to dam break ( $\gamma =0$ ), of constant ( $\gamma =1$ ), waning ( $\gamma <1$ ) and waxing inflow rate ( $\gamma >1$ ). The nonlinear governing equations, developed within the lubrication theory, admit self-similar solutions for some combinations of the parameters involved and for two limiting conditions of low and high local Forchheimer number, a dimensionless quantity involving the local slope of the current profile. Another parameter $N$ expresses the relative importance of the nonlinear term in Darcy–Forchheimer's law; values of $N$ in practical applications may vary in a large interval around unity, e.g. $N\in [10^{-5},10^{2}]$ ; in our experiments, $N\in [2.8,64]$ . Sixteen experiments with three different grain sizes of the porous medium and different inflow rates corroborate the theory: the experimental nose speed and current profiles are in good agreement with the theory. Moreover, the asymptotic behaviour of the self-similar solutions is in excellent agreement with the numerical results of the direct integration of the full problem, confirming the validity of a relatively simple one-dimensional model.

Reflex regulation of model-based biomimetic control for a tendon-driven prosthetic hand

Remarkable compliance of human hands due to muscular biomechanics and neural reflexes, attributes lacking in conventional prosthetic hands. Our prior study replicated neuromuscular reflex in prosthetic control using neuromorphic modeling. Nonetheless, the specific impact of the spinal reflex feedback in biomimetic control on amputees’ manipulation capabilities remains unclear. This study aims to investigate the plausible role of reflex regulation in biomimetic control for tendon-driven prosthetic hands. Eleven subjects with forearm amputations participated in force control tasks and functional tasks. The force control tasks were performed using either the prosthetic forefinger or the entire hand. The functional tasks of varying difficulties included the standard rigid object test (SROT), refined rigid object test (RROT), and fragile object test (FOT). Additionally, the stiffness properties of biomimetic control were tested prior to the human-in-loop evaluations. Closed-loop control (CLC) with integrated proprioceptive feedback and open-loop control (OLC) were employed for assessments. Results showed that the reflex regulation contributed significantly to the increase by 20.4% in success rate, 17.9% in effective throughput, and 65.7% decrease in break rate during in the pressing force control task. CLC consistently outperformed OLC across all indices. Indeed, the gripping force control task revealed comparable trends as well. In functional tasks, the reflex regulation yielded 10.5%, 17.9%, and 146.4% improvements in performance for SROT, RROT and FOT, respectively. The findings highlight the essential role of reflex regulation in biomimetic prosthesis control, providing evidence for enhancing amputees’ fine manipulation abilities by replicating the human sensorimotor functions.

Preparation and optimization of sulfur ferrous inorganic carbon composite filler for autotrophic denitrification nitrogen and phosphorus removal

Sulfur autotrophic denitrification (SAD) occurs without organic carbon sources, offering advantages in removing nitrogen pollutants from water with low carbon to nitrogen ratio. However, ensuring nitrate–reducing sulfide–oxidizing bacteria ability to access the necessary sulfur and inorganic carbon sources is a challenge. Therefore, this study investigated the feasibility of utilizing a SAD composite filler to mitigate nitrogen and phosphorus pollutants concentrations in secondary effluent of wastewater treatment plants (WWTPs) and reduce eutrophication risk in the receiving water. The use of paraffin optimized composite filler with a satisfying 3.70 % break rate and wear rate without dramatically deteriorating contaminant removal performance. The process achieved 94.26 % total nitrogen (TN) and 90.91 % PO43--P removal rates in treating synthetic wastewater; and 2.72 ± 1.92 mg/L and 0.29 ± 0.06 mg/L of TN and PO43--P discharge in treating WWTPs secondary effluent, respectively. The results indicated that denitrification performance of the filler was primarily influenced by variations in NH4+-N resulting from SAD and dissimilatory nitrate reduction to ammonia caused by differences in filler composition and preparation factors. Based on the performance difference in SAD, Fex + leached by H+ in the filler changed, affecting phosphorus removal performance. The change in mechanical properties of the filler was primarily dependent on the surface characteristics of the filler and the content/type of the binder. This study demonstrates the feasibility of using SAD for advanced nitrogen and phosphorus removal from wastewater and applying sulfur/siderite integrated composite filler as a pilot, thereby offering insights for the preparation of SAD fillers.

Analisis Kelayakan Finansial dan Prospek Pertumbuhan Usaha Pengolahan Rumput Laut di Desa Jang

Jang Village, located in Moro District, Karimun Regency, has abundant seaweed resources utilized for various products, including collagen drinks. This study aims to analyze the financial feasibility of seaweed processing using parameters such as Net Present Value (NPV), Internal Rate of Return (IRR), Payback Period (PP), and Break Even Point (BEP). The analysis results indicate that the BEP is 1.236 units, with a BEP in Rupiah of Rp6.946,00, an NPV of Rp195.869.079,29, an IRR of 21%, and a PP of 4.4 months. Based on the evaluation of financial and non-financial aspects, the seaweed processing business run by CV. Moro's Pure Marine Collagen is considered feasible and profitable. The findings of this study are used to develop long-term business strategies, including global market expansion supported by digital marketing and product diversification such as sports supplements and skincare products. Competitive advantage is enhanced through product certification and continuous research. Business sustainability is achieved by implementing environmentally friendly practices and empowering coastal communities, which is expected to support local economic growth and maintain the sustainability of natural resources.

Application of Ethephon Manually or via Drone Enforces Bud Dormancy and Enhances Flowering Response to Chilling in Litchi (Litchi chinensis Sonn.)

Ethephon (2-chloroethylphosphonic acid) is frequently used for flush management in order to maximize flowering in litchi. However, the optimal dosage of ethephon, which balances between flush control effect and the detrimental effect on leaves, is unknown. This study aimed to identify the optimal ethephon dosage and test more efficient ethephon application methods, using a drone for flush control and flowering promotion in litchi. The effects of a single manual full-tree spray of 250, 500 or 1000 mg/L of ethephon in early November on the bud break rate, leaf drop rate, net photosynthetic rate, LcFT1 expression and floral induction (panicle emergence rate and panicle number) in ‘Jingganghongnuo’ litchi were examined in the season of 2021–2022. In the season of 2022–2023, the effects of drone application of 1000 mg/L of ethephon in early November on bud growth and floral induction were observed. The results showed that the manual ethephon treatments were effective at enforcing bud dormancy and elongating the dormancy period and that the effects were positively dependent on dosage. One manual spray of 1000 mg/L of ethephon in late autumn enabled a dormancy period of 6 weeks. The treatments advanced seasonal abscission of old leaves in winter and caused short-term suppression on photosynthesis within 2 weeks after treatment. Ethephon treatments, especially at 1000 mg/L, enhanced the expression of LcFT1 in the mature leaves and promoted floral induction reflected by earlier panicle emergence and increased panicle emergence rate and number in the terminal shoot. The floral promotion effect was also positively dosage dependent. The cumulative chilling hours below 15 °C from the date of treatment to the occurrence of a 20% panicle emergence rate were lowered in ethephon treatments. A drone spray of 1000 mg/L of ethephon solution consumed a sixth of the manual spray solution volume and was two thirds less effective in suppressing bud break compared with manual spraying. However, it achieved a significant flowering promotion effect comparable to traditional manual spraying. The results suggest that ethephon application enhanced flowering responsiveness to chilling as well as enforced bud dormancy. The application of ethephon with a drone proved to be an efficient method for flush control and flower promotion.

Optimization of Operating Parameters for Straw Returning Machine Based on Vibration Characteristic Analysis

For the mechanized technical mode of total wheat straw returning to field, there are problems such as large vibration during the operation of the straw returning machine that, in turn, affect the effect of stubble breaking. This study took the Tongtian 1-JHY-220 straw returning machine as the research object to conduct field experiments, with wheat stubble height, forward velocity, and PTO speed as experimental parameters. And the vibration characteristics at different positions of the machine and the final stubble breaking rate were used as evaluation indicators. Combined with the orthogonal experiment and response surface analysis method, this article analyzes and discusses the influence of various parameters on vibration characteristics and operational effectiveness. The results show that PTO speed and wheat stubble height were the main factors affecting the vibration and operation quality of the straw returning machine. Low PTO speed and high stubble height can improve the stubble breaking rate of the straw returning machine and reduce its operation vibration. Furthermore, the multi-objective optimization results show that when the forward velocity in the range of 8.5–9 km/h, the PTO speed is 540 r/min, and the stubble height is in the range of 200–250 mm, the stubble breaking rate of the straw returning machine is greater than 86%. At this time, the total vibration of the straw returning machine and tractor rear axle is relatively small. This study can lay a foundation for further studying the impact of the vibration of the straw returning machine on the stubble breaking effect and provide a reference for the preparation of high-quality seedbed under conservation tillage.

Porosity of green body: A potential essential factor regulating the making of sintered ceramsite from aluminum-based drinking water treatment residuals

Ceramsite is commonly applied in filtration systems for water treatment and aluminum (Al)-based drinking water treatment residue (DWTR) has been widely reported to have high potential to be recycled as main ingredient to make the sintered ceramsite. Various key factors affecting ceramsite making (e.g., composition and sintering temperature) have been identified to promote the beneficial recycling; however, according to sintering processes, this study hypothesized that porosity of green body was also a potential key factor, and then moisture content of green body (33 %-40 %) and particle size of DWTR (< 425 μm), which were the parameters initially considered for ceramsite making, were adopted to regulate the porosity for affecting characteristics and mechanisms investigation. The results verified the hypothesis and showed that increasing moisture content tended to decrease loss on ignition, apparent density, and bulk density, to increase water absorption, and to cause rougher surface of ceramsites, promoting the maximum Cu adsorption capacity of the ceramsite (estimated by Langmuir model); while at medium level of moisture content (e.g., 35 %), a relatively high compressive strength, strong Cu adsorbability (evaluated by Freundlich model), and low solubility in hydrochloric acid were found. Moreover, larger sized DWTR tended to increase loss on ignition, broken rate, solubility in hydrochloric acid, silt content, and water absorption, to reduce apparent density and compressive strength, and to cause rougher surface of the ceramsite, promoting the maximum adsorption capacity and decreasing the adsorbability of Cu. Further analysis suggested that moisture content was mainly through regulating total volume of voids and amount of raw materials to affect sintering, while particle size was mainly through regulating the contacting of particles. These results demonstrated the importance of the moisture contents of green body and the particle size of DWTR on affecting sintered ceramsite making, and porosity of green body was recommended to be taken as an essential factor when determining the optimal condition to make sintered ceramsite making.

Phenyl, propyl polysiloxane modified epoxy resin II: The co-continuous phase, concurrently strengthening and toughening mechanism

The applications of epoxy resins are restricted in certain areas due to their brittleness, while improving the epoxy toughness always compromises their strength. We reported a phenyl, propyl polysiloxane modified epoxy resins with excellent tensile strength and toughness before. In this study, the mechanism of strengthening and toughening are studied and elaborated. Compared to cured EP resin (EP), cured P/E resin (P/E20) significantly improved the tensile strength, elongation at break, impact strength, and critical strain energy release rate (GIc) by 45 %, 248 %, 18 %, and 512 %, respectively. Fracture analysis of the P/E20 revealed the appearance of parabolic markings, typical and convincing evidence of ductile fracture, indicating good toughness of the resin. AFM height and Young's modulus plots reveal the complex details of the dimples and the co-continuous phases, which provide the strong evidence to explain the reinforcement and toughening mechanism.

Ultrasonic-assisted extraction of nanocellulose from sweet potato residue and its application in noodles.

Enhancing the amount of dietary fiber without compromising the quality of noodles remains a challenge in the food industry. This study aimed to optimize the ultrasound-assisted extraction parameters to enhance the yield of nanocellulose from sweet potato residue (SPR) using a response surface methodology. The impact of SPR nanocellulose on noodles' physicochemical properties was also explored. Results showed that the optimal extraction conditions for nanocellulose from SPR were identified as 180.73 U/mL cellulase concentration, 4.28 h ultrasonic time, 444.12 W ultrasonic power, and 14.17 h enzymatic hydrolysis time. The max yield of nanocellulose was 15.93% at optimum extraction conditions. Increasing the amount of SPR nanocellulose resulted in a reduction in the optimal cooking time, water absorption, elongation index, and springiness, as well as an increase in the breaking rate, cooking loss, hardness, gumminess, and chewiness of the noodles. Sensory analysis revealed higher acceptability of the noodles with 6%-12% SPR nanocellulose compared to other treatments. Microstructure demonstrated that noodles with 0%-18% SPR nanocellulose exhibited fewer holes and denser network structures, but higher SPR nanocellulose damaged the protein network. Those findings suggested that noodles with less than 12% SPR nanocellulose exhibited higher quality. This research provided the foundation for the development of nanocellulose-enriched foods.

Alternative double strand break repair pathways shape the evolution of high recombination in the honey bee, Apis mellifera.

Social insects, particularly honey bees, have exceptionally high genomic frequencies of genetic recombination. This phenomenon and underlying mechanisms are poorly understood. To characterise the patterns of crossovers and gene conversion in the honey bee genome, a recombination map of 187 honey bee brothers was generated by whole-genome resequencing. Recombination events were heterogeneously distributed without many true hotspots. The tract lengths between phase shifts were bimodally distributed, indicating distinct crossover and gene conversion events. While crossovers predominantly occurred in G/C-rich regions and seemed to cause G/C enrichment, the gene conversions were found predominantly in A/T-rich regions. The nucleotide composition of sequences involved in gene conversions that were associated with or distant from crossovers corresponded to the differences between crossovers and gene conversions. These combined results suggest two types of DNA double-strand break repair during honey bee meiosis: non-canonical homologous recombination, leading to gene conversion and A/T enrichment of the genome, and the canonical homologous recombination based on completed double Holliday Junctions, which can result in gene conversion or crossover and is associated with G/C bias. This G/C bias may be selected for to balance the A/T-rich base composition of eusocial hymenopteran genomes. The lack of evidence for a preference of the canonical homologous recombination for double-strand break repair suggests that the high genomic recombination rate of honey bees is mainly the consequence of a high rate of double-strand breaks, which could in turn result from the life history of honey bees and their A/T-rich genome.

Impacts of climate change on the transcriptional dynamics and timing of bud dormancy release in Yoshino‐cherry tree

Societal Impact StatementThe iconic Yoshino cherry tree in Japan is experiencing shifts in its blossom timing due to climate warming. To develop a genetically informed predictive model for bud dormancy release, we examined seasonal gene expression in Yoshino cherry trees at three different locations. Our experiments, coupled with the analysis of DORMANCY‐ASSOCIATED MADS‐box (DAM) genes, highlighted DAM4 as the most reliable indicator for the rate of bud dormancy release. Our study demonstrated that seasonal gene expression profiles serve as a valuable indicator for forecasting the timing of dormancy release, benefiting Japanese traditions and providing insights into the biological impacts of climate change.Summary The Yoshino cherry tree Cerasus × yedoensis ‘Somei‐yoshino’ stands out as an iconic springtime symbol in Japan. For the Yoshino cherry trees to bloom in the spring, dormant buds must undergo a period of exposure to low temperatures, allowing them to break dormancy. Key genes related to dormancy release, known as DORMANCY‐ASSOCIATED MADS‐box (DAM), have been extensively studied. However, it remains unclear how these genes function in natural environments to regulate the timing of bud dormancy release. To develop a genetically informed predictive model for bud dormancy release, we explored seasonal changes in genome‐wide gene expression profiles in the Yoshino cherry trees at three distinct sites in Japan. Five distinct genome‐wide transcription profiles, subjectively named as modes—early summer, summer, autumn, winter, and spring—were identified, with the winter and spring modes observed when the daily mean temperature was below approximately 10°C. Our experiments of bud dormancy release, along with the assessment of expression profiles of DAM genes, have revealed that among the six DAM genes, DAM4 expression profile is the most indicative of the rate of bud dormancy break. Our estimates suggest that, on average, the tree needs to be exposed to temperatures below 10.1°C for 61.1 days to suppress DAM4 expression to the threshold required for bud dormancy release. Our projections for the timing of bud dormancy release indicated a delay of approximately 2.3 days per decade from 1990 to 2020. Our study demonstrated that gene expression serves as a valuable indicator for forecasting the timing of dormancy release.

Development of a low-damage maize threshing system based on discrete element technology to effectively improve maize harvest quality and yield

During maize harvesting, the mechanical action and suboptimal design of threshing systems often lead to kernel breakage and loss, which can reduce both maize quality and yield. This study introduces a novel rasp bar threshing element designed to minimize kernel loss. The effects of the structural parameters of this threshing element on its performance are analyzed using a flexible discrete element model of maize. Moreover, the performance of the novel threshing element is compared to that of a traditional threshing element, and the simulation results are verified through experimental tests. Test data shows that, compared to the traditional threshing element, the novel threshing element results in a relative decrease of 26.94 %, 21.95 %, and 27.05 % in the broken rate, unthreshed rate, and the entrainment loss rate, respectively. Finally, this research provides technical support for high-quality, low-loss maize production.

The impact of molecular configuration on the bond breaking rates of hydrocarbons: a computational study.

The dissociation of hydrocarbon bonds plays a pivotal role in their utilization, whether through fuel combustion or the thermo-cracking of large hydrocarbons in petroleum refinement. Previous studies have primarily focused on the effects of temperature, pressure, and chemical environment on hydrocarbon reactions. However, the influence of molecular configuration on bond breaking rates has not been thoroughly explored. In this study, we propose an approach to compute bond dissociation rates, and apply it to the reactive molecular dynamics simulation (ReaxFF) trajectories of three molecules: n-tridecane, n-pentane, and 1,3-propanediol. Our results reveal that the bond dissociation rate depends not only on the bond position in the chain, but also on the molecular configuration. Stretched configurations exhibit higher dissociation rates, particularly favoring the breaking of central bonds. Conversely, when the molecule is coiled, resulting in a reduced size, terminal bonds exhibit higher dissociation rates. This research contributes to a deeper understanding of molecular dissociation properties in the oxidation of hydrocarbons, and provides a way to explore the bond breaking properties of other molecules.

Shell Distribution of Vitamin K3 within Reinforced Electrospun Nanofibers for Improved Photo-Antibacterial Performance.

Personal protective equipment (PPE) has attracted more attention since the outbreak of the epidemic in 2019. Advanced nano techniques, such as electrospinning, can provide new routes for developing novel PPE. However, electrospun antibacterial PPE is not easily obtained. Fibers loaded with photosensitizers prepared using single-fluid electrospinning have a relatively low utilization rate due to the influence of embedding and their inadequate mechanical properties. For this study, monolithic nanofibers and core-shell nanofibers were prepared and compared. Monolithic F1 fibers comprising polyethylene oxide (PEO), poly(vinyl alcohol-co-ethylene) (PVA-co-PE), and the photo-antibacterial agent vitamin K3 (VK3) were created using a single-fluid blending process. Core-shell F2 nanofibers were prepared using coaxial electrospinning, in which the extensible material PEO was set as the core section, and a composite consisting of PEO, PVA-co-PE, and VK3 was set as the shell section. Both F1 and F2 fibers with the designed structural properties had an average diameter of approximately 1.0 μm, as determined using scanning electron microscopy and transmission electron microscopy. VK3 was amorphously dispersed within the polymeric matrices of F1 and F2 fibers in a compatible manner, as revealed using X-ray diffraction and Fourier transform infrared spectroscopy. Monolithic F1 fibers had a higher tensile strength of 2.917 ± 0.091 MPa, whereas the core-shell F2 fibers had a longer elongation with a break rate of 194.567 ± 0.091%. Photoreaction tests showed that, with their adjustment, core-shell F2 nanofibers could produce 0.222 μmol/L ·OH upon illumination. F2 fibers had slightly better antibacterial performance than F1 fibers, with inhibition zones of 1.361 ± 0.012 cm and 1.296 ± 0.022 cm for E. coli and S. aureus, respectively, but with less VK3. The intentional tailoring of the components and compositions of the core-shell nanostructures can improve the process-structure-performance relationship of electrospun nanofibers for potential sunlight-activated antibacterial PPE.

Influence of carboxy-terminated hyperbranched polyester and polyethylene glycol on the mechanical and thermal properties of polylactic acid/straw flour composites

Polylactic acid (PLA) wood-plastic composites have a significant advantage over traditional petroleum-based plastics due to their biodegradability. However, PLA has several shortcomings, including high brittleness, low heat resistance, slow crystallization, and poor compatibility with biomass materials, which have limited its potential applications. In this paper, we investigated the effects of carboxy-terminated hyperbranched polyester (CHBP) on the mechanical, crystalline, and thermal properties of PLA/straw flour (SF) blends through extrusion injection molding. Additionally, we added the traditional plasticizer polyethylene glycol (PEG) to synergize with CHBP to enhance the toughness of PLA/SF composites. Our results showed that the appropriate addition of CHBP effectively improved the interfacial bonding between PLA and straw flour. The incorporation of CHBP also improved the tensile strength, bending strength, impact strength, elongation at break, thermal stability, and crystallization rate of the composites. Furthermore, the addition of both CHBP and PEG significantly improved the impact strength of the composites compared to using PEG alone. This method also improved the heat resistance of the material and reduced the migration of plasticizers. Our study demonstrates the feasibility of using hyperbranched polymers and plasticizers to enhance the toughness, thermal stability, and crystalline properties of PLA wood-plastic composites, providing a new approach to improving the properties of these composites.

The Design and Experimentation of a Wheeled-Chassis Potato Combine Harvester with Integrated Bagging and Ton Bag-Lifting Systems

The mechanized harvesting level of potatoes in the arid areas of Northwest China is low and mainly relies on simple machinery to dig the soil surface, and then people manually pick up and bag the potatoes. This harvesting method has the problems of a high labor intensity, low operation efficiency, and high labor cost. Based on this, a wheeled-chassis potato combine harvester with integrated bagging and ton bag-lifting systems was developed, which could complete potato digging, potato–soil separation, potato–film separation, automatic bagging, and field ton bag lifting in one go. Firstly, based on the agronomic requirements and unique terrain characteristics of potato planting in this area, the structural design of the whole machine was completed with SOLIDORKS 2019 3D software. Secondly, the dynamic model was established for a numerical analysis, and the core parameters of key components were determined. The field experiments showed that the potato loss rate was 2.1%, the potato damage rate was 1.7%, the skin breaking rate was 2.5%, the impurity content was 1.9%, and the productivity was 0.15~0.23 hm2/h. The above field test indexes met the requirements of national and industrial standards.

Parametric Analysis and Numerical Optimization of Root-Cutting Shovel of Cotton Stalk Harvester Using Discrete Element Method

Aiming at solving the problems of the high cost of manual pulling, the low reliability of existing pulling devices, and the high breaking rates and high leakage rates in the process of cotton stalk reuse after removal from the field in the Xinjiang cotton area, a soil-loosening and root-cutting cotton stalk pulling and gathering machine was researched and designed; a root-cutting force model was established; the key parameters of the V-shaped root-cutting knife were calculated and optimized; and the ranges of the slide cutting angle, the cutting-edge angle, and the soil entry angle were determined. A shoveling process simulation of the V-shaped root-cutting knife and the root–soil complex was constructed, and the working mechanism of the V-shaped root-cutting knife was clarified. In order to verify the reliability and operation performance of the V-shaped root-cutting knife, the slide cutting angle, the cutting-edge angle, and the soil entry angle were used as the test factors, and a response surface test with three factors and three levels was carried out with the root-breaking force and the mean value of the cutting resistance as the test indices. The test results were analyzed by variance analysis, and the significant factors influencing the root-breaking force in descending order were the slide cutting angle, cutting-edge angle, and soil entry angle. The degrees of influence on the mean value of the cutting resistance were ordered as follows: slide cutting angle, soil entry angle, and cutting-edge angle. In order to make the V-shaped root-cutting knife achieve the optimal working state, the parameters of the test indices were optimized, and the optimal design parameters of the V-shaped root-cutting knife were set as follows: the slide cutting angle was 48.3°, the cutting-edge angle was 43.4°, and the soil entry angle was 26.2°. The field uprooting test showed that the average pass rate of root breakage was 94.8% and the average pull-out rate of cotton stalks was 93.2%. This study provides theoretical guidance for the development of a root-breaking mechanism for cotton straw harvesters.