High Impurity Research Articles

基于两段式薯土分离装置甘薯联合收获机设计与试验

Aiming at the problems of high skin-breaking rate and high impurity rate of sweet potato during harvesting operations, a low-damage fresh-eating sweet potato combine harvester based on a two-segment potato-soil separation device was designed by using a “d”-type elevator chain combined with a double-buffer clearing platform technology. The results show that the best working parameters of the harvester are a vibrating shaft frequency of 5.2 Hz, elevator chain speed of 0.37 m/s, and cleaning platform speed of 0.58 m/s, in which the sweet potato skin-breaking rate is 1.09% and the impurity rate is 1.90%, which is in line with standard.

基于 Adams 的间隙可调弹性低损玉米摘穗割台的设计与试验

To address the high damage rate and impurity content in corn ear picking, this study proposes the design of a gap-adjustable elastic low damage corn picking header. Theoretical analysis of the adaptive gap adjustment mechanism for the picking plate and the flexible picking mechanism will be conducted. Simulation experiments will be performed considering three factors: the stiffness coefficient of the compression spring, the rotational speed of the stalk-pulling roller, and the thickness of the flexible body. The test results indicate that the minimum collision force on the fruit cluster occurs when the stiffness coefficient of the compression spring is 36 N/mm, the rotational speed of the stalk-pulling roller is 700 r/min, and the thickness of the flexible body is 6 mm. When the header tilt angle was 25 degrees and the working speed was 3 km/h, using the stalk roller speed as the experimental variable, the collision force of the gap-adjustable elastic low-damage corn picking header was compared to that of the ordinary plate-type corn picking header. The results indicated that the collision force of the gap-adjustable elastic low-damage corn picking header was reduced by more than 25 % compared to the ordinary plate-type corn picking header.

Study on the reaction mechanism and kinetics of limestone hydrogenation by micro fluidized bed: Effect of H2 concentration and natural limestone

Limestone decomposition is the first step in cement production, which produces a significant amount of CO2 and poses a significant challenge to achieve carbon neutrality. Hydrogenation of limestone can produce CO or CH4 instead of CO2, which can be considered as a new way of carbon capture, making it a promising method for carbon emission reduction. In this work, pure CaCO3 and several natural limestone samples were hydrolyzed under varying H2 concentration using a micro fluidized bed (MFB) reactor combined with online mass spectrometry to reveal the mechanism and kinetics of limestone hydrogenation.The main gases produced by hydrogenation at 1 atm are CO and CO2. The CO2 comes from the calcination of CaCO3. The CO comes from 2 steps: the first step is the in-situ hydrogenation of CaCO3 and the second step is the Reverse Water Gas Shift (RWGS) reaction. The activation energy (Ea) of CO2 formation in H2 atmosphere is lower than in Ar atmosphere. However, there is no obvious effect of different H2 concentrations on the Ea of CO2 formation. The Ea of CO in situ formation is 72.70 KJ/mol, 54.53 KJ/mol, 71.34 KJ/mol and 60.29 KJ/mol in 10%, 30%, 50% and 70% H2 atmosphere, respectively. The H2 concentration also has no significant effect on the in-situ CO evolution. However, the H2 concentration can affect the Ea of CO produced by RWGS. The Ea is 75.67 KJ/mol, 167.59 KJ/mol and 221.47 KJ/mol in 10%, 30% and 50% H2 atmosphere, and this reaction doesn't occur in 70% H2 atmosphere. Compared with the pure CaCO3, the hydrogenation of limestone can produce more CO and less CO2. In limestone, impurity elements are the main factor affecting the reaction kinetics. Transition metals can increase the rate of CO2 production, but have no apparent effect on CO. The CO2 yield of high impurity limestone is higher than that of limestone with low impurities. Transition metals can also reduce the Ea of CO2 formation and the RWGS reaction. In the 50% H2 atmosphere, the Ea of CO2 formation is 88.87 KJ/mol and the Ea of CO from RWGS is 137.60 KJ/mol. However, under the same conditions, the Ea of pure CaCO3 is 126.91 KJ/mol and 221.47 KJ/mol.

Parameter Optimization of Spiral Step Cleaning Device for Ratooning Rice Based on Computational Fluid Dynamics-Discrete Element Method Coupling

Ratooning rice plants have a high moisture content and strong adhesion during harvesting. Traditional cleaning devices are prone to clogging when processing ratooning rice, resulting in a series of problems such as high grain loss rate and high grain impurity rate. In response to the above issues, this article adopts the CFD-DEM coupling method to design a spiral step cleaning device. A detailed analysis was conducted on the influence of the cone angle and thickness of the spiral-stepped skeletons on the flow state, and flow velocity and pressure distribution cloud maps were obtained under different structural parameters. The vortex morphology under different thicknesses of the spiral-stepped skeletons was compared, and the structural parameters of the device were determined. The motion trajectory and distribution of impurity particles under different inlet flow velocities were analyzed using data superposition, and the appropriate inlet flow velocity range was determined. A test bench was built, and a three-factor quadratic regression orthogonal rotation combination experiment was conducted with fan speed, feeding rate, and device inclination angle as experimental factors. The results of the bench test show that the performance index reaches its optimum when the device inclination angle, fan speed, and feeding rate are 2.47°, 2906 r/min, and 4.0 kg/s, respectively. At this time, the grain impurity rate, grain loss rate, and sieve clogging rate are 2.21%, 2.15%, and 3.5%, respectively. Compared to those of traditional cleaning equipment, these value are reduced by 44.5%, 39.6%, and 83.9%, respectively. This study can provide ideas for the design of ratooning rice cleaning devices.

Effect of H3PO4 coordination on vanadium extraction and iron separation in a H2SO4 leaching system.

The selectivity of the full wet leaching process for vanadium extraction using H2SO4 is low, resulting in a high impurity content in vanadium extracted from vanadium-bearing shale. This study focused on vanadium extraction and iron separation from vanadium-bearing shale, involving the coordination of H3PO4 in an H2SO4 leaching system. The effects of the ratio and quantity of H2SO4-H3PO4, leaching time, leaching temperature, and liquid-to-solid ratio on vanadium-bearing shale leaching were investigated. The dissolution processes of various minerals and the mechanism of iron coordination precipitation were analyzed. Results showed that vanadium leaching efficiency was 91.07% and iron leaching efficiency decreased from 84% to 23.86% under optimal leaching conditions-H2SO4-to-H3PO4 ratio of 2 : 1, H+ content of 8 mol kg-1, liquid-to-solid ratio of 0.8 L kg-1, and leaching time of 12 h at 95 °C. Leaching kinetics showed that the leaching process of vanadium shale was a mixed-control process in the H3PO4-H2SO4 leaching system; additionally, the leaching process was mainly controlled by a chemical reaction with an activation energy of 67 kJ mol-1. The preferential dissolution order of minerals in the vanadium-bearing shale was calcite, apatite, magnetite, muscovite, and pyrite. Under the H2SO4-H3PO4 leaching system, the iron content was reduced by inhibiting the dissolution of pyrite and coordination precipitation of Fe3+ with PO4 3-, thus separating iron and vanadium from the source. This provides guidance for vanadium extraction and impurity separation from vanadium-bearing shale using an all-wet method.

ECW assisted plasma startup with low toroidal electric field and full metal wall in EAST superconducting tokamak

Abstract Recent experimental results from the EAST superconducting tokamak with a full metal wall (without Li-coating) provide strong support for the ITER startup scheme with electron cyclotron wave (ECW) assistance. Detailed investigations were performed on the impact of different magnetic field geometries, including quadrupolar field configuration (QFC), wide null field configuration (NFC), and trapped particle configuration (TPC). All three configurations enabled the breakdown of neutral gas with ECW pre-ionization. However, in most discharges with QFC, the absence of closed flux surfaces after the breakdown was associated with unsuccessful plasma startups. Conversely, both NFC and TPC achieved successful plasma startups under normal conditions, with TPC demonstrating higher robustness against high impurity levels compared to NFC. Experiments found that the minimum ECW power required for a successful TPC startup is approximately 0.48 MW. Plasma startup failed if the prefill gas pressure exceeded optimal levels for a given ECW power (≥0.48 MW), with the critical gas pressure linearly dependent on the ECW power. Additionally, higher ECW power was required with increased impurity levels. With ECW assistance, the toroidal electric field at R=1.85 m in EAST routine operations (<0.15 V/m) is significantly lower than ITER's maximum value (0.3 V/m), suggesting the possibility of reducing flux consumption and lowering demands on coils and power supplies for ITER.

Ethyl biodiesel production from crude soybean oil using enzymatic degumming-transesterification associated process

Brazil is one of the largest soybean producers in the world. Biodiesel production in Brazil (specially soybean oil biodiesel) has been growing every year and demanding more effective and sustainable technologies, which is the case of enzymatic processes. Enzymatic degumming could be an alternative to provide better quality products, before biodiesel production but also, in a one reaction step as a proposal to reduce time and costs. Therefore, this work was aimed at evaluating enzymatic degumming (previously optimized) of crude soybean oil using a phospholipase cocktail associated with transesterification using lipase from Aspergillus oryzae for ethyl biodiesel production. For this, transesterification was optimized for ethanol:oil (E:O) ratio, water and lipase % through a central composite rotatable design (CCRD). Optimal conditions were used to evaluate two degumming-transesterification associated processes: i) a one-pot reaction (OPR) where degumming and transesterification were performed at the same reactor; and ii) a two-pot reaction (TPR) where oil was first degummed, followed by transesterification. The optimal transesterification condition were achieved for E:O = 4.48:1, water = 3.41 % and lipase = 2.43 %, where 97 % fatty acid ethyl esters (FAEE) were obtained. Both OPR and TPR provided biodiesels with FAEE > 94 %: TPR was the best with 97.5 % and 99.98 % before and after biodiesel purification. Mineral elements (including phosphorus) and other impurities (anions) were low, and within quality standards. Glycerol produced also presented very low content of impurities which is quite advantageous. Although lipase achieves good conversion to FAEE (95.7 ± 0.29 %) using crude oil (Control), the final biodiesel carries many impurities (P=80.07 ± 0.1 mg/kg), thus requiring subsequent biodiesel purification steps. In addition, the high impurity content generates a biodiesel that does not comply with ANP legislative standards, P<10 mg/kg. The use of enzymatic degumming in the biodiesel production process generates a biodiesel with low impurities and higher final quality, in addition to being a process that generates less effluent. Enzymatic degumming was essential for obtaining high quality biodiesel and its association with transesterification showed to be a great option for decreasing time and costs for biodiesel production.

Optimum Design of Profiled Root–Trimming Device for Pull–Cut Harvester of Leading–Drawing–Cutting Type

In this study, a leading–drawing–cutting–type profiled root–trimming device was designed to address the problems of high impurity and damage rates that occur with the operation of a pull–cut garlic harvester. The main components of the designed device include a pull–clamp mechanism, roll–pulling mechanism, root–trimming knife mechanism, lifter, gearbox, universal drive shaft, motor, and frame that, together, can complete the root–trimming operation for a pull–cut garlic harvester. An orthogonal regression test was carried out by taking the roller diameter, the roller inclination angle, the knife rotation speed, and the working speed as factors and by taking the impurity rate and the damage rate as indices. The results of the orthogonal regression test showed that the impurity rate was most strongly affected by the roller diameter, followed by the knife rotation speed, the working speed, and the roller inclination angle. Meanwhile, the damage rate was most strongly affected by the knife rotation speed, followed by the roller diameter, the working speed, and the roller inclination angle. The regression analysis showed that when the roller diameter was 100 mm, the roller inclination angle was 25°, the knife rotation speed was 200 r·min−1, and the working speed was 1.22 km·h−1, the comprehensive trimming quality reached its maximum value of 97.82%. The verification result of the parallel test gave a value of 97.52%, which was mainly affected by the irregular sizes of the bulbs, but it showed no significant difference from the regression analysis results. The tests verified that the profiled root–trimming device could be applied to develop the technology of garlic pull–cut harvesters.

Polycrystalline silicon photovoltaic cell defects detection based on global context information and multi-scale feature fusion in electroluminescence images

In photovoltaic (PV) cell inspection, electroluminescence (EL) imaging provides high spatial resolution for detecting various types of defects. The recent integration of EL imaging with deep learning models has enhanced the recognition of defects in PV cells. However, the high surface impurity content in polycrystalline silicon PV cells presents a challenge. Defect features can be similar to complex background textures, making highlighting features for small target defects difficult and leading to potential misclassification as background or other classes. To address these challenges, we propose a novel deep convolutional neural network (CNN) model for effectively identifying small target defects in polycrystalline PV cells. We first utilize a global context information (GCI) block to improve CNN’s modeling of global information, aiding in distinguishing PV cell defects with similar local details. Moreover, we design a channel weight feature pyramid (CWFP) that dynamically adjusts the channel weights of extracted features. We further achieve multi-scale feature fusion through the pyramid structure to enhance the resolution capability for small targets. The proposed model was evaluated on a publicly available dataset of 8 defect classes in polycrystalline PV cells, achieving an accuracy of 96.36 %. The experimental results show that the proposed model outperforms existing deep learning models in detecting small target defects with higher precision.

A CC-NB-ARC-LRR Gene Regulates Bract Morphology in Cotton.

Bracts are leaf-like structures in flowering plants. They serve multiple functions such as attracting pollinators, aiding tolerance of abiotic stressors, and conducting photosynthesis. While previous studies extensively examine bract function, the molecular mechanisms underlying bract growth remain unknown. Here, the map-based isolation and characterization of a crucial factor responsible for cotton bract development, identified from a mutant known as frego bract (fg), discovered by Frego in 1945 are presented. This gene, named Ghfg, encodes a CC-NB-ARC-LRR (CNL) family protein. Through analysis of bract form in plants with virus-induced gene silencing (VIGS) and transgenic plants, this gene is confirmed to be the causal gene under the fg locus. Furthermore, high-resolution single-cell transcriptomic landscape of cotton bracts is generated, which reveals differences related to auxin in proliferating cells from TM-1 and T582; differences in auxin distribution and ROS accumulation are experimentally verified. These findings suggest that GhFG is in a self-activated state in the fg mutant, and its activity leads to ROS accumulation that impacts auxin distribution and transport. Finally, an island cotton variety with the frego bract trait is developed, demonstrating a novel solution for reducing the high impurity rate caused by bract remnants.

Feasibility analysis on the debrining for compressed air energy storage salt cavern with sediment

Using the sediment void to store gas is a promising solution for the construction of compressed air energy storage (CAES) salt cavern with high impurity. However, it remains debatable whether the pressure loss of brine in the sediment can notably affect debrining. In this paper, the in-situ sediments are obtained, and their porosity, moisture content after debrining and permeability are measured. A model of debrining in salt cavern with sediment is built. The model prediction error of injection gas pressure is less than 0.34 %. A criterion for the feasibility evaluation of debrining for CAES salt cavern with sediment is proposed. The results show that the porosity of the in-situ sediment is 47.9 %. When the sediment volume reaches 98 % of the cavern volume, the pressure loss of brine in the sediment and the maximum gas pressure are less than 3.1 MPa and 17 MPa, respectively. The sediment has good permeability, it is feasible to debrine in salt cavern with sediment. It is suggested that the debrining rate and the tubing diameter increase to more than 120 m3/h and 0.14 m, respectively. This study provides valuable guidance for the debrining in salt caverns with sediment.

Overview on aluminium alloys as sinks for end-of-life vehicle scrap

Abstract A fundamental principle in metallurgy is that the higher the purity of metals and alloys, the more favourable their properties will be. However, as the recycling of materials in production becomes increasingly significant, the levels of impurities are also on the rise. In the case of aluminium, the consequences can be detrimental due to the low solubility of most elements in this metal, which leads to the formation of brittle intermetallic phases (IMPs). Moreover, once impurities have entered aluminium, it is difficult to remove them. In 2017, almost 100 million cars were produced worldwide. Historically, vehicle design prioritised performance, resulting in a multi-material mix to utilise the best materials for each application. This included over 40 different wrought and cast aluminium alloys, Cu-based materials for electrics, and steels for high-strength applications. In the recycling of end-of-life vehicles (ELVs), high purity wrought Al alloys are today down-cycled to low purity cast engine blocks. However, recent advancements show that the drawback of increase IMP-fractions can be turned into benefits through the strategic design of heterostructured alloys. A first successful alloy example from this approach enables interesting forming properties, previously only found in 5xxx series wrought aluminium alloys, in combination with a matrix composition and age-hardening potential known from 6xxx series wrought aluminium alloys. A second examples reviews compositions directly resulting from ELV scrap. By manipulating IMPs it is feasible to create heterostructures with an interesting balance of strength and ductility. These approaches challenge traditional views, allowing for a greater volume fraction of intermetallic phases. Understanding the formation and role of intermetallic particles is crucial. This work gives an overview to the current problem and the state of the art and addressed the potential of upcycled aluminium alloys that tolerate high impurity levels by using intermetallic phases as impurity sinks.

Isolation and characterization of alginate producing Azotobacter sp, isolated from rhizospheric soil of Oryza sativa (L.) and Triticum aestivum (L.)

Alginate as biopolymer consisting of β-D Mannuronic acid and α-L Guluronic acid monomer residues linked by (1-4) glycosidic bond. Brown seaweeds mostly Laminaria sp, Ascophyllum nodosum, Eclonia maxima, Sargassum sp. and Macrocystis pyrifera were earlier used for commercial alginate production. Major drawback of using sea weeds for alginate production were high production cost, impurity issue and safety concerns includes the reasons behind discovery of novel bacterial sources to make an efficient alginate production system. Later two bacterial genera Pseudomonas and Azotobacter were reported for alginate production. However, due to pathogenicity, and quality issue associated with some Pseudomonas strains, Azotobacter sp. was found to be most reliable and prioritized bacterial sources for alginate production with appreciable qualities which will be ready to be used for industrial applications. Therefore, current research aims to isolate and characterize a new strain of Azotobacter sp. with alginate-producing ability. Two different soil samples were collected from two places Deokali and Parsurampur, Jaunpur district in the spring (06 August 2022) and winter (06 February, 2023) seasons from Oryza sativa and Triticum aestivum rhizospheric region respectively. Azotobacter sp. was isolated by using Nitrogen Free Burk’s medium and alginate production was confirmed by gel formation assay method in the presence of CuSO4 and CaCl2 solutions. The carbohydrate qualitative test was done by using Molisch’s Test. Two novel strains Azotobacter chroococcum PU-RSD01 and Azotobacter chroococcum PU-RSD02 were isolated on the basis of high alginate producing ability. Morphological, biochemical and molecular techniques further characterized the isolates.

Use of differential scanning calorimetry as a rapid, effective in-process check method for impurity quantitation of an early clinical batch of Giredestrant (GDC-9545)

Giredestrant (GDC-9545) is a selective estrogen receptor degrader (SERD) that was developed for treatment of ER+/HER2− metastatic breast cancer. An anhydrous crystalline tartrate salt was identified as the solid form suitable for clinical development. An early clinical batch of the active pharmaceutical ingredient (API)/drug substance failed to pass the GMP purity specifications owing to the presence of a substantial amount of high molecular weight impurities (oligomers), as determined by size exclusion chromatography. Several trial rework batches were manufactured using various re-slurry and recrystallization conditions to purge impurities in the drug substance to adhere to purity specifications. Based on the melting point depression of the API in presence of oligomers in these rework batches, a differential scanning calorimetry method was developed to quantify impurity content as a function of melting point onset of the API. This thermal analysis method was used as a surrogate for chromatography as a rapid, effective in-process check method for impurity quantitation to enable the timely release of the final reworked clinical batch. Post release, the % w/w oligomer value determined by calorimetry was in excellent agreement to that obtained by size exclusion chromatography.

花生清选筛台架的设计与试验

In order to address the high impurity and loss rates in the cleaning process of existing peanut combine harvesters, the design basis of the cleaning sieve was explored. Tests were conducted to determine the composition of the peanut picking fruit and the characteristics of the material suspension mixture. Additionally, the mechanical relationship between the fruit and miscellaneous mixtures and the cleaning sieve was investigated. The wind speed ranged from 8 m/s to 10 m/s, the vibration frequency ranged from 6 Hz to 8 Hz, and the inclination angle of the sieve ranged from 5° to 9°. The scavenger sieve platform was constructed and tested using Box-Behnken’s central combination test method. The optimal combination of fan wind speed (9 m/s), sieve surface inclination angle (8°), and sieve vibration frequency (7 Hz) resulted in a pod impurity rate of 1.16% and a loss rate of 1.4%. The device significantly reduces impurity content and loss rate during peanut harvesting. The study's results can serve as a reference for improving the design of the peanut combine harvester cleaning mechanism and optimizing operating parameters.

Coal and Coal By-Products as Unconventional Lithium Sources: A Review of Occurrence Modes and Hydrometallurgical Strategies for Metal Recovery

Lithium, a critical material for the global development of green energy sources, is anomalously enriched in some coal deposits and coal by-products to levels that may be considered economically viable. Recovering lithium from coal, particularly from coal gangue or coal ashes, offers a promising alternative for extracting this element. This process could potentially lead to economic gains and positive environmental impacts by more efficiently utilizing coal-based waste materials. This review focuses on lithium concentrations in coal and coal by-products, modes of lithium occurrence, methods used to identify lithium-enriched phases, and currently available hydrometallurgical recovery methods, correlated with pretreatment procedures that enable lithium release from inert aluminosilicate minerals. Leaching of raw coal appears inefficient, whereas coal gangue and fly ash are more feasible due to their simpler composition and higher lithium contents. Lithium extraction can achieve recovery rates of over 90%, but low lithium concentrations and high impurity levels in the leachates require advanced selective separation techniques. Bottom ash has not yet been evaluated for lithium recovery, despite its higher lithium content compared to feed coal.

Large-scale production of cefazolin in a microreactor with a low impurity content and high yield

Cefazolin is crucial in the field of healthcare because of its efficacy against bacterial diseases, but trace amounts of polymer impurities produced during synthesis may cause severe allergic reactions. In this work, an efficient system based on a membrane dispersion microreactor was designed for scalable cefazolin production with a high yield and low impurity content. At a production scale of 200 kg, the yield could reach 90 %, and the polymer impurity content could reach <0.008 %. Density functional theory calculations were used to investigate the formation mechanisms of the polymer impurities. The results revealed that the activation energy of cefazolin ring-opening and substitution reactions decreased by 22.4 kJ/mol and 6.4 kJ/mol respectively under alkaline conditions, resulting in increased polymer content. Computational fluid dynamics simulation indicates that the organic base in the substrate can be rapidly dispersed in the membrane dispersion microreactor, thus avoiding excessive local base concentration. In conclusion, the development of a membrane dispersion microreactor system offers a scalable and efficient method for cefazolin production with significantly lower polymer impurity content, thereby addressing a critical challenge in antibiotic synthesis and ensuring safer and more reliable healthcare applications.

Constructing the Electron-Rich Microenvironment of an All-Polymer-Based S-Scheme Homostructure for Accelerating Uranium Capture from Nuclear Wastewater.

Large quantities of uranium-containing radioactive wastewater are typically generated during nuclear fuel cycle processes. Despite significant efforts, efficient capture of migratable hexavalent uranium U(VI) is still a huge challenge due to its acidity, radioactivity, coexisting organics, and high impurity cation abundance in wastewater. Herein, we have fabricated all-polymer-based 0D/2D C4N/C6N7 homostructure hybrids with an S-scheme electronic configuration by coordinating the band engineering of semiconductors to enrich uranium species from the complex wastewater environment. The sample can capture over 97% of U(VI) in the actual concentration of nuclear industrial reprocessing wastewater; also, the U(VI) enrichment ratio still exceeds 95% when the irradiation dose (including α, β, and γ) is up to 100 kGy. Density functional theory and X-ray absorption spectroscopy demonstrate that the aggregation of charge carriers on the surface of the sample regulates the electron-rich microenvironment, thus accelerating the reduction conversion of single electron reaction uranium disproportionation. It is expected that this work can provide more insight into other functional materials, thereby promoting uranium removal advancements in nuclear wastewater.

Systematic study of polymer gas sampling bags for offline analysis of exhaled breath

Polymeric bags are a widely applied, simple, and cost-effective method for the storage and offline analysis of gaseous samples. Various materials have been used as sampling bags, all known to contain impurities and differing in their cost, durability, and storage capabilities. Herein, we present a comparative study of several well-known bag materials, Tedlar (PVF), Kynar (PVDF), Teflon (PTFE), and Nalophan (PET), as well as a new material, ethylene vinyl copolymer (EVOH), commonly used for storing food. We investigated the influences of storage conditions, humidity, bag cleaning, and light exposure on volatile organic compound concentration (acetone, acetic acid, isoprene, benzene, limonene, among others) in samples of exhaled human breath stored in bags for up to 48 h. Specifically, we show high losses of short-chain fatty acids (SCFAs) in bags of all materials (for most SCFAs, less than 50% after 8 h of storage). We found that samples in Tedlar, Nalophan, and EVOH bags undergo changes in composition when exposed to UV radiation over a period of 48 h. We report high initial impurity levels in all the bags and their doubling after a period of 48 h. We compare secondary electrospray ionization and proton transfer reaction mass spectrometry in the context of offline analysis after storage in sampling bags. We provide an analytical perspective on the temporal evolution of bag contents by presenting the intensity changes of all significantm/zfeatures. We also present a simple, automated, and cost-effective offline sample introduction system, which enables controlled delivery of collected gaseous samples from polymeric bags into the mass spectrometer. Overall, our findings suggest that sampling bags exhibit high levels of impurities, are sensitive to several environmental factors (e.g. light exposure), and provide low recoveries for some classes of compounds, e.g. SCFAs.

Design and Experimental Study of a Cleaning Device for Edible Sunflower Harvesting

Existing cleaning devices for edible sunflower have a low cleaning efficiency, high cleaning loss rate, and high impurity rate; therefore, a wind-sieve-type cleaning device for edible sunflower harvesting was designed. According to the characteristics of dislodged objects, a vibrating screen for the device was designed, and the dislodged edible sunflower objects in the device were used for a mechanical analysis of the force conditions to determine the displacement of the different edible sunflower objects dislodged by the action of airflow. Using FLUENT-DEM gas–solid coupling simulation technology, the velocity of the flow field, the velocity vector, and the trajectory of the dislodged objects inside the cleaning device were analyzed, and the law of motion applied to the airflow and the dislodged objects inside the device was clarified. According to the results of the coupled simulation analysis, the key factors affecting the operation of the cleaning device were wind speed, vibration frequency, and amplitude. Based on the key factors of wind speed, vibration frequency, and amplitude, an orthogonal rotary combination test was carried out with the loss rate and impurity rate of cleaned grains as the evaluation indexes, and the test parameters were optimized to obtain the optimal combination of operating parameters of the device, which were as follows: wind speed: 30 m·s−1; vibration frequency: 8.44 Hz; and amplitude: 41.35 mm. With this combination of parameters, the seed loss rate and impurity rate reached 3.47% and 6.17%, respectively. Based on the optimal combination of operating parameters, a validation test was performed, and the results of this test were compared with the results of the test bench using this combination of parameters. The results show that the relative errors of the loss rate and impurity rate between the bench test and the simulation test were 3.45% and 3.07%, respectively, which are less than 5%, proving the reliability of the simulation analysis and the reasonableness of the design of the test bench.