Large Fillet Research Articles

Tandem mass tag-based quantitative proteomics analysis of modified atmosphere packaging in large yellow croaker (Pseudosciaena crocea) fillets during refrigerated storage

A tandem mass tagging-labeled proteomic approach was employed to explore the relationship between quality parameters and protein changes in large yellow croaker fillets refrigerated under carbon dioxide, oxygen, and nitrogen atmospheres. After 96 h, fillets stored in carbon dioxide and nitrogen showed improved texture, water-holding capacity, and color, compared to those stored in oxygen. Functional analysis respectively identified 117 and 65 differentially expressed proteins in carbon dioxide and nitrogen, including key proteins such as troponin, myosin light chain, actin, and collagen types IV and XIII, that were linked to extracellular adhesion, cytoskeleton integrity, energy metabolism, and membrane functions. Carbon dioxide and nitrogen were detrimental to the growth and reproduction of aerobic microorganisms. High concentrations of carbon dioxide can inhibit microbial activity, while nitrogen preserves freshness by regulating the pressure balance within the packaging. These findings provided a theoretical basis for the optimized gas-conditioned preservation of large yellow croaker fillets.

Effect of konjac glucomannan-based preservation pads on quality changes in refrigerated large yellow croaker (Pseudosciaena crocea)

The purpose of this study was to evaluate the preservation effects of konjac glucomannan (KGM)/oregano essential oil (OEO) Pickering emulsion-based pads (K/OPE pads) on large yellow croaker (Pseudosciaena crocea) fillets stored at 4 °C. The K/OPE pads were fabricated using a freeze-drying technique. The homogeneous distribution of the OEO Pickering emulsions in the KGM matrix was observed using scanning electron microscopy. Fourier transform infrared spectroscopy confirmed that the OEO emulsions were encapsulated in the KGM and there was hydrogen bonding interaction between them. Compared with the KGM pads, the K/OPE pad groups demonstrated enhanced antioxidant and antimicrobial properties. When the content of OPE was increased from 20 % to 40 %, the antioxidant performance of the K/OPE pads increased from 48.09 % ± 0.03 % to 86.65 % ± 0.02 % and the inhibition range of Escherichia coli and Staphylococcus aureus increased to 13.84 ± 0.81 and 16.87 ± 1.53 mm, respectively. At the same time, K/OPE pads were more effective in inhibiting the formation of total volatile alkaline nitrogen and the production of thiobarbituric acid-reactive substances, thereby helping in reducing water loss and maintaining the muscle tissue structure of fish fillets for a longer storage time. Consequently, these K/OPE40 pads extended the shelf life of the fish fillets by an additional 4 days and delayed spoilage during refrigerated storage. The findings suggest that the K/OPE pads can effectively safeguard the quality of refrigerated large yellow croaker fillets, presenting their potential as an active packaging material in the fish preservation industry.

Effect of gum tragacanth–sodium alginate coatings incorporated with epigallocatechin gallate on the quality and shelf life of large yellow croaker (Larimichthys crocea) during superchilling storage

Abstract The effect of gum tragacanth (GT) and sodium alginate (SA) active coatings incorporated with epigallocatechin gallate (EGCG; 0.16%, 0.32%, and 0.64%, respectively) on the quality of large yellow croaker fillets was evaluated during superchilling storage at –3 ˚C for 42 d. The results revealed that the GT-SA-EGCG active coatings delayed microbial spoilage by reducing the total viable counts of Pseudomonas spp. and psychrophile bacteria and retarded the degradation of the physical properties of water-holding capacity, cooking loss, color, odor and texture. GT-SA-EGCG coatings could also maintain fillet freshness by maintaining lower total volatile basic nitrogen, K value, and histidine content, inhibiting myofibrillar protein degradation during superchilling storage. These results suggested that the active coatings embedded with GT-SA-EGCG could be used as a preservative to enhance the quality of large yellow croaker and prolong the shelf life by 7–14 d during superchilling storage at –3 ˚C.

Effects of Rosemary Extract and Chlorogenic Acid on Lipid and Protein Oxidation in the Sous Vide Processed Large Yellow Croaker Fillet Product During Cold Storage

ABSTRACT Large yellow croaker fish fillets were sous vide processed and stored at 2°C for 4 weeks. Rosemary extract and chlorogenic acid were used to inhibit the lipid and protein oxidation. Rosemary extract and chlorogenic acid could significantly reduce levels of peroxide value (45% and 60%) and thiobarbituric acid reactive substances (39% and 47%) at the end of storage. Rosemary extract and chlorogenic acid reduced the carbonyl content by 40% and 51%, respectively, during storage but not the sulfhydryl loss during the sous vide processing step. Phenol–protein interaction needed to be studied further for quality improvement/evaluation in the future.

Quality changes of Larimichthys crocea pretreated by ultrasonic-assisted immersion under cold storage at 4 °C

The effects of several ultrasonic treatments during cold storage at 4 °C on the quality of large yellow croaker (Pseudosciaena crocea) were suggested. Large yellow croaker fillets were divided into six different groups for treatment. (a) CK (without any treatment), (b) A (single frequency 20 kHz), (c) B (single frequency 40 kHz), (d) C (left and right dual frequency 20 + 40 kHz), (e) D (orthogonal dual frequency: left and right 40 kHz, upper and lower 20 kHz), and (f) E (orthogonal dual frequency: left and right 20 kHz, upper and lower 20 kHz). The samples were divided into six groups, placed in sterile PE bags, and chilled to 4 °C. In order to determine the impact of ultrasonic treatment on the quality of large yellow croaker during cold storage, microbial indicators and physical and chemical indicators were measured every 3 days. The total number of colonies, the percentage of psychrophilic bacteria, the sample's pH, and its TVB-N value were all shown to grow at a much slower pace following ultrasonic treatment. In addition, the antibacterial effect of dual frequency ultrasound was gradually better than that of single frequency ultrasound. In conclusion, Group D has a pretty excellent impact on preserving overall sample quality.

Nonmigrating Active Antibacterial Packaging: Antimicrobial Mechanism against Staphylococcus Aureus and Its Application in Large Yellow Croaker

In this study, chitosan (CS) was grafted onto the surface of polylactic acid (PLA) film by covalent immobilization to prepare four kinds of CS-grafted PLA (CS-g-PLA) films with different molecular weights. The properties of the films were characterized, and their antibacterial effect and mechanism of action against Staphylococcus aureus (S. aureus) were explored. After being treated with CS-g-PLA films, the cell morphology was destroyed, the permeability of the cell membrane changed, and malate dehydrogenase (MDH) activity decreased. Furthermore, the large yellow croaker fillets were packaged by the films mentioned above and stored at 4 °C, the physicochemical changes and microbial counts were measured. The results showed that the CS-g-PLA films could effectively delay the decay of fish fillets for 1–4 days. Overall, this study demonstrated that grafted films showed great application potential in aquatic product packaging and preservation.

Proximate Composition, Retained Water, and Bacterial Load for Two Sizes of Hybrid Catfish (Ictalurus furcatus × Ictalurus punctatus) Fillets at Different Process Steps.

The catfish processors in the US are required to state the maximum percentage of retained water content (RWC) on the product label. The objectives of our study were to quantify the RWC of processed hybrid catfish fillets from proximate composition and the bacterial load at different processing points. Water content was determined using oven-dry (AOAC950.46,1990) and Near-infrared (NIR) spectroscopy. Protein and fat content were determined by NIR spectrometer. Psychrotrophic (PPC) and Total Coliform (TCC) counts were enumerated using 3MPetrifilmTM. The fillets' overall baseline water, protein, and fat content were 77.8, 16.7 and 5.7%, respectively. The RWC of final fresh and frozen fillets were ~1.1=/- 2.0% (not significant) and ~4.5%, respectively, and was not fillet size or harvest season dependent. Baseline water content (78.0 vs. 76.0%) was higher (p ≤ 0.05), and fat content (6.0% vs. 8.0%) was lower (p ≤ 0.05) for small (50-150 g) compared to large fillets (150-450 g). Higher (p ≤ 0.05) baseline PPC (~4.2 vs. ~3.0) and TCC (~3.4 vs. ~1.7) were observed for the warm season (April-July) fillets compared to the cold season (Feb-April). This study provides information to processors and others on estimating retained water and microbiological quality of the hybrid catfish fillets over the process line.

Determining the Effect of Process Parameters on Shearing Strength of Rotated Clinching Joint Using the Response Surface Method

Rotated clinching is a novel cold plastic deformation joining process, which is suitable for the multi-point simultaneous joining of sheet metals. However, the effect of various parameters on the mechanical properties of joints using rotated clinching remains unclear. The purpose of this study is to analyse the important parameters that affect the joint’s shearing strength and relationship between them. The relational expression between the four process parameters (die depth, rotation angle, small fillet radius and large fillet radius) and joint shearing strength was established using the response surface method. Additionally, the quantitative relationship between them was expressed by this relational expression, and the significance of process parameters were evaluated using the analysis of variance. The results revealed that the most significant parameter regarding the shearing strength was die depth h, with the contribution of 47.1%, followed by rotation angle α and small fillet radius r1, with the contributions of 26.8% and 8.2%, respectively, whereas the large fillet radius R1 is the least significant, there is a significant interaction effect between R1 and α, with the contribution of 5.4%. The shearing strength had a negative relationship with the die depth h and small fillet r1, whereas it had a positive relationship with rotation angle α. The predicted maximum value of the shearing strength was 1231.92 N at h = 2.29 mm, r1 = 0.46 mm, R1 = 1.27 mm and α = 18.45° in the range of given design parameter values. The experimental values of the shearing strength comprised approximately 74% of the predicted values.

Structural Optimization Design and Strength Test Research of Connecting Rod Assembly of High-Power Low-Speed Diesel Engine

The connecting rod assembly of a high-power low-speed diesel engine has high quality and high cost. If the connecting rod component is damaged, the whole machine may be paralyzed, resulting in serious economic losses and safety problems, so it is necessary to carry out strength analysis and structure optimization, reduce the failure rate, and increase its life. This paper takes the connecting rod of a low-speed diesel engine as the research object, builds the crank connecting rod mechanism model, and carries on the strength simulation analysis through professional simulation software. During this period, the accurate S-N curve of connecting rod material is obtained through a fatigue test, and the static strength test of the connecting rod assembly is carried out by an electro-hydraulic servo universal testing machine. The numerical modeling is validated based on the test results. Therefore, the influence of the structural parameters of the cross-section and the large end transition fillet on the stress of the connecting rod is analyzed. The results show that optimizing matching between the large end fillet of the connecting rod and the long diameter of the rod section not only reduces the mass but also improves the safety factor. After optimizing the structure of the connecting rod, the mass of the connecting rod is reduced by 5.85%, the maximum stress is reduced by 13.7%, and the safety factor is increased by 16.0%. In addition, due to the low-speed diesel engine connecting rod assembly weight is big, and the simulation computation efficiency is low, this paper by studying the influence of the cross-section parameters of the rod body and the large end transition fillet on the stress of the connecting rod, fitted the empirical formula calculating the maximum stress of connecting rod, for this model and similar type in the conceptual design, technology design provides a new analysis method, improved the efficiency of structural optimization and strength analysis of connecting rod assembly, filled the research gap of strength analysis and structural optimization of low-speed diesel engine connecting rod.

Design of Longitudinal-Bending Coupled Horn of a Giant Magnetostriction Transducer

This article presents a design method of Longitudinal-Bending Coupled Horn (L-BCH) of a giant magnetostrictive transducer utilized in spinning ultrasonic machining. The structural parameters are initially determined by the design theory of the horn and thick disc. Then, the effect of the structural parameters of the rotating wheel on the vibration characteristics of the L-BCH are explored by the model and harmonic response analysis through the finite element method. Through continuous modification of the geometrical parameters of the rotary wheel, the L-BCH meeting the requirements of a giant magnetostrictive transducer is designed. Finally, the frequency and amplitude measurements are performed on the prototype by the impedance analyzer and the laser vibrometer. The finite element analysis and experimental results show that: the large diameter, small diameter, thickness, and fillet radius of the rotating wheel have different impacts on the dynamic characteristics of the L-BCH. Among them, the thickness of the rotary wheel has the most significant influence on the natural frequency and amplitude. In addition, the rotating wheel has a pitch circle when the longitudinal-bending coupled vibration occurs, and the structure itself also has the characteristic of amplifying amplitude.

Impact of theaflavin soaking pretreatment on oxidative stabilities and physicochemical properties of semi-dried large yellow croaker (Pseudosciaena crocea) fillets during storage

The effect of theaflavin pretreatment on changes in quality of semi-dried large yellow croaker fillets was investigated and compared with a water-soaking treatment during storage. The data indicated that the springiness, chewiness, L*, and b* values of the control and theaflavin-treated fillets both showed significantly decreasing trends during 5 days of room-temperature and 40 days of chilled storage. However, the incorporation of theaflavins exhibited positive effects on the texture and color stability of the fillet samples. Importantly, the antioxidant theaflavin treatment significantly inhibited the rapid increase of the TVBN content, reduced the peroxide and thiobarbituric acid index values, and slowed the changes in the myofibrillar carbonyls and surface hydrophobicity during storage when compared with those of the water-soaking treatment. Additionally, histological observations verified that the theaflavins showed pronounced effects on the stability of myofibrillar proteins (MPs) and remarkably inhibited MP and lipid oxidation during the two types of storage.

Optimization Design of Short Shell Structure of Rocket Fuel Tank Based on Kriging Surrogate Model

Abstract Aiming at the weight reduction optimal design of short shell structure of rocket fuel tank, this paper deals with the structural optimization under the action of axial load. First, the accuracy of equivalent stiffness method is verified by post-buckling analysis of short shell in ABAQUS. Then, according to the parametric model of short shell, based on Kriging surrogate model and EGO algorithm, the optimal structure without and with fillet are obtained under the given design load. Finally, a parametric study is carried out on the influence of fillet on the bearing capacity per unit mass of short shell. The results show that when the width of rib or the spacing of transverse rib is small, and the height of rib, the thickness of skin or the spacing of longitudinal rib is large, processing large fillet for load-bearing purpose is less beneficial or even disadvantageous.

Effects of cold treatments on lipidomics profiles of large yellow croaker (Larimichthys crocea) fillets by UPLC-Q-Exactive Orbitrap MS analysis

Cold treatment offers an effective avenue to preserve large yellow croaker fillets. However, the lipid distribution of fillets is unclear after cold treatments. This study aimed to identify differences of lipids among the fresh (RAW) and two cold treatments (− 1 ℃ and − 3 ℃) of large yellow croaker fillets using a lipidomics approach. A total of 2317 lipid species in RAW and two cold treatments were recognized and assigned to 13 sub-classes of lipids by using ultra-high-performance liquid chromatography-Q-exactive orbitrap mass spectrometry (UPLC-Q-Exactive Orbitrap MS) and lipidsearch software approach. Furthermore, there are 54 significantly different lipids were selected as potential lipid candidates of lipid oxidation of fillets by using correlation analysis between all individual lipids variables and freshness indicators (color, pH, thiobarbituric acid reactive substances, and total volatile bases nitrogen). All these potential candidates had involved 6 metabolic pathways that found the significant metabolic process on lipid oxidation after cold treatments. The autophagy-animal and glycerophospholipid metabolism were found to be two important pathways to analyze the lipids change, and were used to find the significant potential candidates of lipid oxidation on cold treatment. This work could provide a novel insight on the lipid changes analysis of large yellow croaker fillets after cold treatments.

The quality properties of frozen large yellow croaker fillets during temperature fluctuation cycles: improvement by cellobiose and carboxylated cellulose nanofibers

Frozen aquatic products undergo unavoidable quality changes owing to temperature fluctuations during frozen storage and distribution. This study investigated the effects of 1% cellobiose (CB), and 0.5 and 1% carboxylated cellulose nanofibers (CNF) on ice crystal growth and recrystallization of frozen large yellow croaker fillets exposed to temperature fluctuations. Denser and more uniformly distributed ice crystals were observed in the CB- and CNF-treated samples than in the water-treated samples. Furthermore, the addition of CB and CNF suppressed the conversion of bound water to frozen water in the samples during temperature fluctuation cycles, played a positive role in fixing the ionic and hydrogen bonds that stabilize the protein structure, limited the conformational transition from α-helix to β-sheet, and improved protein thermal stability. Based on turbidity, zeta potential, and confocal laser scanning microscopy (CLSM) analyses, the presence of CB and CNF restricted the protein aggregation. Compared with CB, CNF molecules with abundant carboxyl functional groups and longer morphology exhibited better cryoprotective effects. Moreover, the fillets were more improved protected from mechanical damage induced by large ice crystals at a higher CNF concentration. This study reveals the potential of CB and CNF as novel cryoprotectants.

Simulation Study on the Effect of Flue Gas on Flow Field and Rotor Stress in Gas Turbines

A flue gas turbine is the main energy recovery equipment in a heavy oil catalytic cracking unit. Blade erosion and fracture are the main reasons for gas turbine failure. In this study, the characteristics of the flow field and rotor stress in the gas turbine under different fume volumes are simulated and analyzed by simulation software (ANSYS). The influences of fume volume on the high-temperature fume flow field, temperature, velocity, catalyst particle movement rotor stress in the gas turbine, as well as the influence law of flue gas flow on temperature gradient, pressure gradient, velocity distribution, and the main position of blade erosion were studied. The stress distribution and maximum stress position of the impeller were also determined. It was found that the variation trends of the pressure gradient in the calculation domain of the gas turbine under different fume volumes are similar. The pressure on the working face of the rotor blade decreases gradually along the flow direction of the high-temperature fume. The highest pressure appears near the sharp corner with the large radius of the front edge of the rotor blade. The variation of the fume flow rate has little influence on the temperature field of the entire machine. The erosion wear of the rotor blade mainly occurs in the leading edge and tail. The maximum stress point of the blade is located at the large fillet of the first pair of tenon teeth. The maximum stress point of the disc is located at the large fillet of the third pair of tenon teeth. It is believed that these research results have reference help for analyzing the typical failure causes of flue gas turbine, optimizing the actual operating conditions and the reconstruction design of flue gas turbine.

Artificial Intelligence Empowered Multispectral Vision Based System for Non-Contact Monitoring of Large Yellow Croaker (Larimichthys crocea) Fillets.

A non-contact method was proposed to monitor the freshness (based on TVB-N and TBA values) of large yellow croaker fillets (Larimichthys crocea) by using a visible and near-infrared hyperspectral imaging system (400–1000 nm). In this work, the quantitative calibration models were built by using feed-forward neural networks (FNN) and partial least squares regression (PLSR). In addition, it was established that using a regression coefficient on the data can be further compressed by selecting optimal wavelengths (35 for TVB-N and 18 for TBA). The results validated that FNN has higher prediction accuracies than PLSR for both cases using full and selected reflectance spectra. Moreover, our FNN based model has showcased excellent performance even with selected reflectance spectra with rp = 0.978, R2p = 0.981, and RMSEP = 2.292 for TVB-N, and rp = 0.957, R2p = 0.916, and RMSEP = 0.341 for TBA, respectively. This optimal FNN model was then utilized for pixel-wise visualization maps of TVB-N and TBA contents in fillets.

The use of effective full penetration of T-butt welds in welded moment connections

Full-penetration butt welds are often specified to connect the beam flanges to the column flange in welded moment resisting connections. Partial-penetration butt welds are cheaper than full-penetration butt welds and also more cost effective when compared to large fillet welds. EN 1993-1-8 standard includes a definition of an “effective full penetration of T-butt welds” implying that it can be used to replace butt welds leading to cost savings. This study evaluates the seismic performance of welded beam-to-column connections using effective full penetration of T-butt welds. Three full-scale T-shaped specimens were tested under cyclic loading. The results demonstrate that the effective full-penetration butt welds work very well under seismic loading, forcing the failure mode into the beam and enabling considerable energy to be dissipated within the beam plastic hinge, with no failure in the beam to column welds. Mock-up specimens were fabricated under real workshop conditions to examine the feasibility of reliably fabricating the weld penetration profiles required by EN 1993-1-8. This paper makes recommendations to the use of “equivalent strength” partial-penetration butt welds that can be used by the designer and/or fabricator to replace full-penetration butt welds.

Metallurgical Investigation of Cold-formed Fillet Pieces Made of Metastable Austenitic Stainless Steel, for the Turbine Exhaust Casing of a Heavy-Duty Gas Turbine Engine

Abstract With a novel class of heavy-duty gas turbine engines, turbine exhaust temperatures are expected to further increase. There are concerns that the propensity to cracking in service of the welded turbine exhaust casing (TEC) liners might also increase. Cold-formed “collars”, featuring large stress-reducing fillet radii, were designed to decrease thermal stresses in the welds, where the struts of the turbine bearing casing are aerodynamically clad by liner plates. Such collars were received from a supplier in the course of a product and process qualification (PPQ). The results of the metallurgical investigation ordered by an internal client are the subject of this contribution. It was found that deformation martensite was present in the subject cold-formed fillet pieces, despite a pre-heat of 150 °C and a post-fabrication 920 °C annealing process. However, the amount of deformation martensite found, at below 5 % volume fraction, was considered not to be detrimental for engine operation.

Experimental investigation of adhesive fillet size on barely visible impact damage in metallic honeycomb sandwich panels

Aluminum hexagonal honeycomb panels are commonly used in the aerospace industry to reduce weight due to their high stiffness to mass ratio. The panels are commonly involved in incidents where they are dented in the out-of-plane direction which causes plastic deformation in the face-sheet and buckling collapse of the thin repeating cell-walls in the core. This paper investigates the responses to barely-visible-impact-damage (BVID) in aluminum honeycomb sandwich panels in the out-of-plane direction with attention to the structural adhesive. The structural adhesive forms a fillet shape between the face-sheet and the aluminum core during the curing process and in some cases can encompass over 50% of the honeycomb core thickness. The adhesive fillets become stiff after curing and are able to brace the thin metallic cell-walls and prevent buckling in sections of the core enclosed in adhesive. It was shown that larger fillets cause the damage to occur deeper in the core. Force-displacement data collected from quasi-static experiments showed that as the amount of adhesive used in honeycomb panels was increased, the peak force required to produce a specified maximum dent depth increased as well. Absorbed energy positively correlated with an increasing quantity of adhesive; showing improvements of up to 50% when comparing panels with the largest amount of adhesive and no adhesive. This paper provides relationships between the quantity of adhesive used to fabricate metallic honeycomb sandwich panels and the damage resistance and energy absorption under BVID conditions.

Influences of large fillets on endwall flows in a vane cascade with upstream slot film-cooling

Investigations in cascade employ filleted blades to influence the near endwall secondary flows and total-pressure losses. The secondary flows aggravate the aerodynamic losses and endwall thermal stresses in the gas turbine passages. Investigations of different configurations of the slot-bleed flow from the endwall of cascade upstream show significant influences on the near endwall flows. In the present paper, the near endwall flow-field in a linear cascade employing filleted vanes and bleed flow from the upstream endwall slots is measured experimentally. Two fillet profiles are tested, one is larger than the other. The objectives are to quantify the combined effects of endwall fillet, fillet profiles, and film-cooling flow on the endwall region flow-field. The fillet covers the junction of vane and endwall upstream of the cascade throat region. The discontinuous bleed-slots near the cascade entrance provide the film-cooling flow on endwall and simulate the gaps between combustor/nozzle-vane discs or stator/rotor discs in the gas turbine. The inlet Reynolds number of 2.0E+05 is based on the chord length of vane profile. The density and temperature ratios of the coolant flow to mainstream are both about 1.0. The inlet blowing ratio of the film-cooling flow varies between 1.0 and 2.8. The flow-field is measured through the distributions of flow temperature, yaw angle, axial vorticity, and total-pressure losses along the vane passage. The effects on the flow-field are then presented by comparing the cases of filleted vanes with the cases of un-filleted vanes. The results of flow yaw angle and axial vorticity in the filleted passage are smaller than those in the passage without the fillet. The yaw angles responsible for the endwall secondary flows are the smallest for the smaller fillet (Fillet-2). The temperature field indicates the pitchwise distributions of the coolant on endwall specially near the pressure side are better when the smaller fillet is employed. Also, the weakened passage vortex of the endwall secondary flows in the filleted passage reduces the total-pressure losses. Although the total-pressure losses decrease at very high coolant mass flux with and without the fillet, the losses are always smaller for the filleted passage than for the un-filleted passage. The present investigation is beneficial for improving and optimizing the endwall film-cooling in the gas turbine passage.