Mechanical Analysis Research Articles

A material point method analysis of failure mechanism and kinematic behavior of rainfall-induced landslide

A material point method analysis of failure mechanism and kinematic behavior of rainfall-induced landslide

Quantitative urinary proteome analysis reveals potential biomarkers for disease activity of Behcet’s disease uveitis

PurposeBehçet’s disease-associated uveitis (BDU) is a severe, recurrent inflammatory condition affecting the eye and is part of a systemic vasculitis with unknown etiology, making biomarker discovery essential for disease management. In this study, we intend to investigate potential urinary biomarkers to monitor the disease activity of BDU.MethodsFirstly, label-free data-dependent acquisition (DDA) and tandem mass tag (TMT)-labeled quantitative proteomics methods were used to profile the proteomes of urine from active and quiescent BDU patients, respectively. For further exploration, the remaining fifty urine samples were analyzed by a data-independent acquisition (DIA) quantitative proteomics method.ResultsTwenty-nine and 21 differential proteins were identified in the same urine from BDU patients by label-free DDA and TMT-labeled analyses, respectively. Seventy-nine differentially expressed proteins (DEPs) were significantly changed in other active BDU urine samples compared to those in quiescent BDU urine samples by IDA analysis. Gene Ontology (GO) and protein-protein interaction (PPI) analyses revealed that the DEPs were associated with multiple functions, including the immune and neutrophil activation responses. Finally, seven proteins were identified as candidate biomarkers for BDU monitoring and recurrence prediction, namely, CD38, KCRB, DPP4, FUCA2, MTPN, S100A8 and S100A9.ConclusionsOur results showed that urine can be a good source of biomarkers for BDU. These dysregulated proteins provide potential urinary biomarkers for BDU activity monitoring and provide valuable clues for the analysis of the pathogenic mechanisms of BDU.

Efficient In Vitro Regeneration System and Comparative Transcriptome Analysis Offer Insight into the Early Development Characteristics of Explants from Cotyledon with Partial Petiole in Small-Fruited Pepper (Capsicum annuum)

In our research, we utilized six small-fruited pepper germplasms as materials, selected cotyledons with the petiole and hypocotyls as explants, and conducted in vitro regeneration studies. Our outcomes specify that the most suitable explant is cotyledon with the petiole, and the suitable genotype is HNUCA341. The optimal medium for inducing and elongating adventitious buds for this genotype is Murashige and Skoog medium (MS) + 9.12 μM Zeatin (ZT) + 0.57 μM 3-Indoleacetic acid (IAA), with a bud induction rate of 44.4%. The best rooting induction medium is MS + 1.14 μM IAA, with a rooting rate of 86.7%. Research on the addition of exogenous hormones has revealed that the induction speed of buds in small-fruited pepper (HNUCA341) in the combination of ZT and IAA hormones (abbreviated as ZI) is quicker, and the induction effect is better. The histological observations indicate that ZI treatment accelerates the initiation of explant division and differentiation, causing a shorter duration of vascular-bundle tissue production. The plant hormone signaling pathway was significantly enriched by Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, including ARR9 (LOC107843874, LOC107843885), ARR4 (LOC107848380, LOC107862455), AHK4 (LOC107870540), AHP1 (LOC107839518), LAX2 (LOC107846008), SAUR36 (LOC107852624), IAA8 (LOC107841020), IAA16 (LOC107839415), PYL4 (LOC107843441), and PYL6 (LOC107871127); these significantly enriched genes may be associated with in vitro regeneration. In addition, the carbon metabolism pathway and plant mitogen-activated protein kinase (MAPK) signaling pathway are also significantly enriched in KEGG. The results of the Gene Ontology (GO) analysis revealed that differentially expressed genes related to carbon metabolism and fixation, photosynthesis and MAPK signaling pathways were upregulated under ZI treatment. It was found that they might be associated with enhanced regeneration in vitro. Furthermore, we also screened out differentially expressed transcription factors, primarily from the MYB, bHLH, AP2/ERF, and NAC families. Overall, our work accumulated important data for the in-depth analysis of the molecular mechanism of in vitro regeneration of pepper, and provides valuable germplasm for establishing an efficient stable pepper genetic-transformation system based on tissue culture.

The Influence of Sulfation Degree of Glycosaminoglycan-Functionalized 3D Collagen I Networks on Cytokine Profiles of In Vitro Macrophage–Fibroblast Cocultures

Cell–cell interactions between fibroblasts and immune cells, like macrophages, are influenced by interaction with the surrounding extracellular matrix during wound healing. In vitro hydrogel models that mimic and modulate these interactions, especially of soluble mediators like cytokines, may allow for a more detailed investigation of immunomodulatory processes. In the present study, a biomimetic extracellular matrix model based on fibrillar 3D collagen I networks with a functionalization with heparin or 6-ON-desulfated heparin, as mimics of naturally occurring heparan sulfate, was developed to modulate cytokine binding effects with the hydrogel matrix. The constitution and microstructure of the collagen I network were found to be stable throughout the 7-day culture period. A coculture study of primary human fibroblasts/myofibroblasts and M-CSF-stimulated macrophages was used to show its applicability to simulate processes of progressed wound healing. The quantification of secreted cytokines (IL-8, IL-10, IL-6, FGF-2) in the cell culture supernatant demonstrated the differential impact of glycosaminoglycan functionalization of the collagen I network. Most prominently, IL-6 and FGF-2 were shown to be regulated by the cell culture condition and network constitution, indicating changes in paracrine and autocrine cell–cell communication of the fibroblast–macrophage coculture. From this perspective, we consider our newly established in vitro hydrogel model suitable for mechanistic coculture analyses of primary human cells to unravel the role of extracellular matrix factors in key events of tissue regeneration and beyond.

The Influence of Sulfation Degree of Glycosaminoglycan-Functionalized 3D Collagen I Networks on Cytokine Profiles of In Vitro Macrophage–Fibroblast Cocultures

Cell–cell interactions between fibroblasts and immune cells, like macrophages, are influenced by interaction with the surrounding extracellular matrix during wound healing. In vitro hydrogel models that mimic and modulate these interactions, especially of soluble mediators like cytokines, may allow for a more detailed investigation of immunomodulatory processes. In the present study, a biomimetic extracellular matrix model based on fibrillar 3D collagen I networks with a functionalization with heparin or 6-ON-desulfated heparin, as mimics of naturally occurring heparan sulfate, was developed to modulate cytokine binding effects with the hydrogel matrix. The constitution and microstructure of the collagen I network were found to be stable throughout the 7-day culture period. A coculture study of primary human fibroblasts/myofibroblasts and M-CSF-stimulated macrophages was used to show its applicability to simulate processes of progressed wound healing. The quantification of secreted cytokines (IL-8, IL-10, IL-6, FGF-2) in the cell culture supernatant demonstrated the differential impact of glycosaminoglycan functionalization of the collagen I network. Most prominently, IL-6 and FGF-2 were shown to be regulated by the cell culture condition and network constitution, indicating changes in paracrine and autocrine cell–cell communication of the fibroblast–macrophage coculture. From this perspective, we consider our newly established in vitro hydrogel model suitable for mechanistic coculture analyses of primary human cells to unravel the role of extracellular matrix factors in key events of tissue regeneration and beyond.

Structural and ferroelectric transition in few-layer HfO2 films from first principles

Abstract The discovery of ferroelectricity in HfO2-based materials with high dielectric constant has inspired tremendous research interest for next-generation electronic devices. Importantly, films structure and strain are key factors in the exploration of ferroelectricity in the fluorite-type oxide HfO2 films. Here we have investigated the structures and strain-induced ferroelectric transition in the different phases of few-layer HfO2 films (layer number N=1-5). It is found that HfO2 films for all phases are more stable with increasing films thickness. Among them, the Pmn2 1 (110)-oriented film is the most stable, and the films of N=4, 5 occur a P2 1 ferroelectric transition under tensile strain, resulting in polarization about 11.8 μC/cm2 along in-plane a-axis. The ferroelectric transition is caused by the strain, which induces the displacement of Hf and O atoms on the surface to non-centrosymmetric positions away from the original paraelectric positions, accompanied by the change of surface Hf-O bond lengths. More importantly, three new stable HfO2 2D structures are discovered, together with computed electronic structures, mechanical, and dielectric properties analyses. This work provides guidance for theoretical and experimental study of the new structures and strain-tuned ferroelectricity in freestanding HfO2 films.

PREVENTING OF MIGRATION IN FOOD CONTACT POLYVINYL CHLORIDE-BASED STRETCH FILMS WITH POLYLACTIC ACID LAYER

In this study, the effectiveness of biodegradable polylactic acid (PLA) coatings for the prevention of residues migrating through polyvinyl chloride (PVC) films was investigated. PLA films prepared in chloroform at concentrations of 5, 10, 15 and 20 wt% were heat sealed to PVC film surfaces in a hot press (130 °C, 5 min, 5 tons). Physical, mechanical, FTIR and migration analyses were performed on these two-layer films. With PLA coating, the thickness of the films increased, mechanical properties decreased and some changes in color values occurred. It was determined by FTIR that there was no structural change on both surfaces of the films as a result of hot pressing. From the overall migration analysis, no migration was observed in the tests with aqueous food simulants, while migration was detected in fatty food simulants. In the specific migration analysis by GC-MS, di-2-ethylhexyl phthalate (DEHP) migration decreased by 50% with PLA coating. It is concluded that PLA coating of PVC stretch films may be a promising application to reduce migration.

Experimental and Mechanistic Analysis of Bastnaesite Pelletization in the Context of Carbochlorination

Experimental and Mechanistic Analysis of Bastnaesite Pelletization in the Context of Carbochlorination

Parecoxib and 5-Fluorouracil Synergistically Inhibit EMT and Subsequent Metastasis in Colorectal Cancer by Targeting PI3K/Akt/NF-κB Signaling

Colorectal cancer is one of the most common causes of cancer mortality worldwide, and innovative drugs for the treatment of colorectal cancer are continually being developed. 5-Fluorouracil (5-FU) is a common clinical chemotherapeutic drug. Acquired resistance to 5-FU is a clinical challenge in colorectal cancer treatment. Parecoxib is a selective COX-2-specific inhibitor that was demonstrated to inhibit metastasis in colorectal cancers in our previous study. This study aimed to investigate the synergistic antimetastatic activities of parecoxib to 5-FU in human colorectal cancer cells and determine the underlying mechanisms. Parecoxib and 5-FU synergistically suppressed metastasis in colorectal cancer cells. Treatment with the parecoxib/5-FU combination induced an increase in E-cadherin and decrease in β-catenin expression. The parecoxib/5-FU combination inhibited MMP-9 activity, and the NF-κB pathway was suppressed as well. Mechanistic analysis denoted that the parecoxib/5-FU combination hindered the essential molecules of the PI3K/Akt route to obstruct metastatic colorectal cancer. Furthermore, the parecoxib/5-FU combination could inhibit reactive oxygen species. Our work showed the antimetastatic capacity of the parecoxib/5-FU combination for treating colorectal cancers via the targeting of the PI3K/Akt/NF-κB pathway.

Parecoxib and 5-Fluorouracil Synergistically Inhibit EMT and Subsequent Metastasis in Colorectal Cancer by Targeting PI3K/Akt/NF-κB Signaling

Colorectal cancer is one of the most common causes of cancer mortality worldwide, and innovative drugs for the treatment of colorectal cancer are continually being developed. 5-Fluorouracil (5-FU) is a common clinical chemotherapeutic drug. Acquired resistance to 5-FU is a clinical challenge in colorectal cancer treatment. Parecoxib is a selective COX-2-specific inhibitor that was demonstrated to inhibit metastasis in colorectal cancers in our previous study. This study aimed to investigate the synergistic antimetastatic activities of parecoxib to 5-FU in human colorectal cancer cells and determine the underlying mechanisms. Parecoxib and 5-FU synergistically suppressed metastasis in colorectal cancer cells. Treatment with the parecoxib/5-FU combination induced an increase in E-cadherin and decrease in β-catenin expression. The parecoxib/5-FU combination inhibited MMP-9 activity, and the NF-κB pathway was suppressed as well. Mechanistic analysis denoted that the parecoxib/5-FU combination hindered the essential molecules of the PI3K/Akt route to obstruct metastatic colorectal cancer. Furthermore, the parecoxib/5-FU combination could inhibit reactive oxygen species. Our work showed the antimetastatic capacity of the parecoxib/5-FU combination for treating colorectal cancers via the targeting of the PI3K/Akt/NF-κB pathway.

Experimental and Mechanistic Analysis of Bastnaesite Pelletization in the Context of Carbochlorination

Experimental and Mechanistic Analysis of Bastnaesite Pelletization in the Context of Carbochlorination

Does digital technology service foster income gains in rural villages? Evidence from China’s third agricultural census

The application of digital technology service like rural e-commerce service centers (RESCs) has captured considerable attention in China, but existing literature has not yet provided solid empirical evidence regarding its potential to foster rural income gains. Utilizing large-scale survey data from the Third National Agricultural Census (TNAC) of China, this study attempts to investigate the impact and underlying mechanisms of RESCs on income gains across 49,135 villages. The results indicate that RESCs significantly increase village income gains in rural China, which confirm the theory of “space of flows.” In addition, heterogeneity analysis reveals that this income increasing effect is significantly higher in eastern China, as well as in rural villages with migrant populations and college-graduate cadres. The conclusion remains robust even after conducting several robustness checks and instrumental variable estimation. Furthermore, mechanism analysis unveils that RESCs improve village income gains by promoting characteristic agricultural development, encouraging entrepreneurship, and enhancing government funding support. The findings shed light on policy implications for the design and implementation of rural digital technology policies in developing countries.

Robot adoption of family firms: the role of family non-executive directors

PurposeIndustrial robots are of great significance to the long-term development of family firms. Drawing on the lens of the principal–principal conflict, this paper aims to investigate the influence of family non-executive directors on robot adoption in Chinese family firms.Design/methodology/approachThis paper selects the family firms in China from 2011 to 2019 as the sample. Furthermore, the authors manually collected the family non-executive directors and constructed the robot adoption variable utilizing data sourced from the International Federation of Robotics. In brief, this paper constructs a comprehensive framework of the mechanisms and additional tests pertaining to the influence of family non-executive directors on robot adoption.FindingsThis paper finds that family non-executive directors can promote robot adoption in family firms. The underlying mechanism analysis shows that family non-executive directors promote robot adoption by exerting financial and human effects. This paper further finds that the characteristics of family non-executive directors, such as kinship, differential shareholding and excessive directors, affect the role of family non-executive directors. Finally, robot adoption can improve future performance, and the promotional effect is more evident when family members are non-executive directors.Originality/valueThis paper contributes to the related literature from the following two aspects. Firstly, this paper decomposes the types of family directors to understand the role of family non-executive directors, which challenges the assumption that family board members are homogeneous in family firms. Second, this paper expands the research on the factors that influence robot adoption in emerging economies from the micro-enterprise level. In addition, the findings in this paper have managerial implications for family firms to optimize their strategic decisions with the help of the mode of board right allocation.

Variations in the Thermomechanical and Structural Properties during the Cooling of Shape-Memory R-PETG

One of the useful features of 3D-printed specimens of recycled polyethylene terephthalate glycol (R-PETG) is the ability to repetitively develop free recovery as well as the work-generating, shape-memory effect. This behavior is enabled by the R-PETG’s capacity to stiffen during cooling, thus allowing for a new temporary shape to be induced. Aiming to devise an explanation for the polymer’s stiffening, in this study, the variation in some of the R-PETG’s parameters during cooling are emphasized and discussed. The evolution of an R-PETG filament’s shape was monitored during room-temperature-bending heating–cooling cycles. Straight-shape recovery and the complete loss of stiffness were observed at the start and the end of heating, respectively, followed by the forced straightening of the filament, performed by the operator, around 40 °C, during cooling. The tests performed by dynamic mechanical analysis disclosed the rise of the storage modulus (E’) after 100 °C heating followed by either liquid-nitrogen- or air-cooling to room temperature, in such a way that E’ was always larger after cooling than initially. Static tests emphasized a peculiar stress variation during a heating–cooling cycle applied in air, within the heating chamber of the tensile testing machine. Tensile-failure tests were performed at −10 °C at a rate of 100 mm/min, with specimens printed at various deposition directions between 10 and 40° to the transversal direction. The specimens printed at 40°, which had the largest ultimate strains, were broken with tensile rates between 100 and 500 mm/min. Deformation rate increase favored the shift from crazing to delamination failure modes. The correlation between the structural changes, the sharp E’ increase on heating, and the stiffening induced by cooling represents a novel approach that enables the use of 3D-printed R-PETG for the fabrication of the active parts of low-priced lightweight resettable actuators.

Does digital technology service foster income gains in rural villages? Evidence from China’s third agricultural census

The application of digital technology service like rural e-commerce service centers (RESCs) has captured considerable attention in China, but existing literature has not yet provided solid empirical evidence regarding its potential to foster rural income gains. Utilizing large-scale survey data from the Third National Agricultural Census (TNAC) of China, this study attempts to investigate the impact and underlying mechanisms of RESCs on income gains across 49,135 villages. The results indicate that RESCs significantly increase village income gains in rural China, which confirm the theory of “space of flows.” In addition, heterogeneity analysis reveals that this income increasing effect is significantly higher in eastern China, as well as in rural villages with migrant populations and college-graduate cadres. The conclusion remains robust even after conducting several robustness checks and instrumental variable estimation. Furthermore, mechanism analysis unveils that RESCs improve village income gains by promoting characteristic agricultural development, encouraging entrepreneurship, and enhancing government funding support. The findings shed light on policy implications for the design and implementation of rural digital technology policies in developing countries.

Thermo-Mechanical Properties and Phase-Separated Morphology of Warm-Mix Epoxy Asphalt Binders with Different Epoxy Resin Concentrations

The performance and phase-separated microstructures of epoxy asphalt binders greatly depend on the concentration of epoxy resin or bitumen. In this paper, the effect of the epoxy resin (ER) concentration (10–90%) on the viscosity, thermo-mechanical properties, and phase-separated morphology of warm-mix epoxy asphalt binders (WEABs) was investigated using the Brookfield rotational viscometer, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and laser scanning confocal microscopy (LSCM). Due to the high reactivity of epoxy resin, the viscosity of WEABs increases with time. Furthermore, the initial viscosity of WEABs decreases with the ER concentration. Depending on the ER concentration, the viscosity–time behavior of WEABs is divided into three stages: slow (10–40%), fast (50–80%), and extremely slow (90%). In the slow stage, the viscosity slightly increases with the ER concentration, while the fast stage shows an opposite trend. DSC and DMA results reveal that WEABs with 10–80% ER exhibit two glass transition temperatures (Tgs) for cured epoxy resin and bitumen. Moreover, the Tgs of epoxy resin and bitumen increase with the ER concentration. However, WEAB with 90 % ER has only one Tg. LSCM observation shows that phase separation occurs in all WEABs. For WEABs containing 10–40% ER, spherical epoxy particles act as the discontinuous phase and disperse in the continuous bitumen phase. However, in WEABs with 50–90% ER, phase inversion takes place. Contrarily, bitumen particles disperse in the continuous epoxy phase. The damping properties of WEABs with the continuous epoxy phases increase with the ER concentration, while the crosslinking density shows an opposite trend. The occurrence of phase inversion results in a sharp increase in the tensile strength of WEABs. For WEABs with the continuous epoxy phases, the elongation at break increases with the ER concentration. The toughness first increases and then decreases with the ER concentration. A maximum toughness value shows at 70% ER.

Optimizing Processing Parameters for NR/EBC Thermoplastic Vulcanizates: A Comprehensive Full Factorial Design of Experiments (DOE) Strategy

Abstract: This research explores the development of thermoplastic vulcanizate (TPV) blends derived from natural rubber (NR) and ethylene–butene copolymer (EBC) using a specific blend ratio and melt mixing technique. A comprehensive full factorial design of experiments (DOE) methodology is employed to optimize the processing parameters. TPVs are produced through dynamic vulcanization, combining rubber crosslinking and melt blending within a thermoplastic matrix under high temperatures and shear. The physico-mechanical properties of these TPVs are then analyzed. The objective is to enhance their mechanical performance by assessing the influence of blend ratio, mixing temperature, rotor speed, and mixing time on crucial properties, including tensile strength, elongation at break, compression set, tear strength, and hardness. Analysis of variance (ANOVA) identifies the optimal processing conditions that significantly improve material performance. Validation is achieved through atomic force microscopy (AFM), confirming the phase-separated structure and, thus, the success of dynamic vulcanization. Rubber process analyzer (RPA) and dynamic mechanical analyzer (DMA) assessments provide insights into the viscoelastic behavior and dynamic mechanical responses. Deconvolution analysis of temperature-dependent tan δ peaks reveals intricate microstructural interactions influencing the glass transition temperature (Tg). The optimized TPVs exhibit enhanced stiffness and effective energy dissipation capabilities across a wide temperature range, making them suitable for applications demanding thermal and mechanical load resistance. This study underscores the pivotal role of precise processing control in tailoring the properties of NR/EBC TPVs for specialized industrial uses. It highlights the indispensable contribution of the DOE methodology to TPV optimization, advancing material science and engineering, particularly for industries requiring robust and flexible materials.

Operation Mechanism Analysis and Parameter Optimization of Bean Impurity-Separation Device for Tiger Nut Harvester

This study aimed to enhance the efficiency of tiger nut combine harvesters by reducing impurity and loss rates during processing. Scholars focused on analyzing the composition and suspension speed of the bean mixture, leading to the development of a wind-screen impurity-removal method. The wind-screen-type bean-separation device was designed with a cross-flow fan, louver screen, frame, and driving mechanism. Theoretical analysis was employed to discuss the motion characteristics and behavior of the sieve body and material, thereby revealing the screening dynamics of tiger nuts and impurities. Factors such as crank radius, crank speed, and fan speed were identified as crucial for optimizing separation performance. Initial single-factor tests helped narrow down the range of influencing factors. Subsequently, a three-factor, three-level Box–Behnken test was conducted with crank radius, crank speed, and fan speed as variables and impurity rate and loss rate as evaluation indexes. This led to the establishment of a multiple regression equation linking these factors to the evaluation indexes. Through response surface analysis and multi-objective optimization using the regression model, the optimal operational parameters for the device were determined: crank radius of 45 mm, crank speed of 497 r/min, and the fan speed of 1100 r/min. Theoretical calculations predicted an impurity rate of 2.42% and a loss rate of 0.51%. Verification tests confirmed these findings, showing an average impurity rate of 2.53% and a loss rate of 0.56%, which met the mechanized harvesting standards for tiger nuts. Overall, this study introduces a novel method and technical framework for effectively separating tiger nuts from impurities, thereby advancing the mechanization of tiger nut harvesting processes.

3D Porous Polymer Scaffold-Conjugated KGF-Mimetic Peptide Promotes Functional Skin Regeneration in Chronic Diabetic Wounds.

The re-epithelialization process gets severely dysregulated in chronic nonhealing diabetic foot ulcers/wounds. Keratinocyte growth factor (KGF or FGF-7) is the major modulator of the re-epithelialization process, which regulates the physiological phenotypes of cutaneous keratinocytes. The existing therapeutic strategies of growth factor administration have several limitations. To overcome these, we have designed a KGF-mimetic peptide (KGFp, 13mer) based on the receptor interaction sites in murine KGF. KGFp enhanced migration and transdifferentiation of mouse bone marrow-derived MSCs toward keratinocyte-like cells (KLCs). A significant increase in the expression of skin-specific markers Bnc1 (28.5-fold), Ck5 (14.6-fold), Ck14 (26.1-fold), Ck10 (187.7-fold), and epithelial markers EpCam (23.3-fold) and Cdh1 (64.2-fold) was associated with the activation of ERK1/2 and STAT3 molecular signaling in the KLCs. Further, to enhance the stability of KGFp in the wound microenvironment, it was conjugated to biocompatible 3D porous polymer scaffolds without compromising its active binding sites followed by chemical characterization using Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, dynamic mechanical analysis, and thermogravimetry. In vitro evaluation of the KGFp-conjugated 3D polymer scaffolds revealed its potential for transdifferentiation of MSCs into KLCs. Transplantation of allogeneic MSCGFP using KGFp-conjugated 3D polymer scaffolds in chronic nonhealing type 2 diabetic wounds (db/db transgenic, 50-52 weeks old male mice) significantly enhanced re-epithelialization-mediated wound closure rate (79.3%) as compared to the control groups (Untransplanted -22.4%, MSCGFP-3D polymer scaffold -38.5%). Thus, KGFp-conjugated 3D porous polymer scaffolds drive the fate of the MSCs toward keratinocytes that may serve as potential stem cell delivery platform technology for tissue engineering and transplantation.

Operation Mechanism Analysis and Parameter Optimization of Bean Impurity-Separation Device for Tiger Nut Harvester

This study aimed to enhance the efficiency of tiger nut combine harvesters by reducing impurity and loss rates during processing. Scholars focused on analyzing the composition and suspension speed of the bean mixture, leading to the development of a wind-screen impurity-removal method. The wind-screen-type bean-separation device was designed with a cross-flow fan, louver screen, frame, and driving mechanism. Theoretical analysis was employed to discuss the motion characteristics and behavior of the sieve body and material, thereby revealing the screening dynamics of tiger nuts and impurities. Factors such as crank radius, crank speed, and fan speed were identified as crucial for optimizing separation performance. Initial single-factor tests helped narrow down the range of influencing factors. Subsequently, a three-factor, three-level Box–Behnken test was conducted with crank radius, crank speed, and fan speed as variables and impurity rate and loss rate as evaluation indexes. This led to the establishment of a multiple regression equation linking these factors to the evaluation indexes. Through response surface analysis and multi-objective optimization using the regression model, the optimal operational parameters for the device were determined: crank radius of 45 mm, crank speed of 497 r/min, and the fan speed of 1100 r/min. Theoretical calculations predicted an impurity rate of 2.42% and a loss rate of 0.51%. Verification tests confirmed these findings, showing an average impurity rate of 2.53% and a loss rate of 0.56%, which met the mechanized harvesting standards for tiger nuts. Overall, this study introduces a novel method and technical framework for effectively separating tiger nuts from impurities, thereby advancing the mechanization of tiger nut harvesting processes.