This paper investigates the effects of process parameters on the joint strength and process robustness when multi-layered joints of dissimilar metals are produced by ultrasonic metal welding (UMW). ...Three layers of 0.3-mm aluminium sheet are welded with a single 1.0-mm copper sheet which is representative of electric vehicle battery interconnects. A process robustness study in which welding pressure, amplitude of vibration and welding time are varied to produce satisfactory welds is reported. The weld quality is evaluated by performing lap shear and T-peel tests where maximum loads are considered as the quality indicator. Response surfaces are developed to identify the relationship and sensitivity between the input process parameters and output quality indicators. A feasible weldability zone is defined for the first time by identifying the under-weld, good-weld and over-weld conditions based on load-displacement curves and corresponding failure modes. Relying on the weldability zone and response surfaces, multi-objective optimisation is performed to obtain maximum lap shear and T-peel strength which resulted in Pareto frontier or trade-off curve between both objectives. An optimal joint is selected from the Pareto front which is verified and validated by performing confirmation experiments, and further, used for T-peel strength analysis of different interfaces of the multi-layered joint. To conclude, this paper determines both the optimal weld parameters and the robust operating range.
•Orange peel oil could be encapsulated by nanocomplexes of WPC–pectin.•The encapsulation efficiency of orange peel oil was about 70–88%.•The best ratio of WPC to pectin for strong complex formation ...was 4–1.•Smallest particles containing orange peel oil were achieved in pH=6.•The strongest complex coacervation was obtained in pH=3.
Orange peel oil is one of the most common flavorings used in the food industry which is volatile under environmental conditions. Encapsulation is the best way to protect it and control its release. One of the nanoencapsulation systems for food bioactive ingredients is complexation method, which entraps the core materials in a complex of two different biopolymers. In this study, orange peel oil was nanoencapsulated by pectin-whey protein nanocomplexes. After determining the optimum nanocomplex suspensions containing orange peel oil based on the stability, viscosity, and color, they were formulated in three different pH values (3, 6 and 9) and converted into powdered forms by freeze drying. The analysis of size and zeta potential of nanocomplexes revealed that the smallest particles formed in pH=6. The encapsulation efficiency of the powders at pH=3, 6 and 9 were 88, 84, and 70%, respectively and there was a reverse linear correlation between encapsulation efficiency and the color index (b*). The microstructure and the morphology of the nanocomplex powders was investigated by SEM and AFM and the results showed that more spherical particles are formed in pH=3. FTIR analysis determined that there was a chemical reaction and bond formation between whey proteins and pectin as a sharp band was appeared in 991cm−1.
Manufacturing thermoplastic composites (TPCs) with excellent mechanical properties require advanced methods with reduced costs and better overall efficiencies. In this study, fiber-reinforced ...thermoplastic polymer composite laminates were manufactured using an automated fiber placement (AFP) manufacturing technology. The effects of processing temperature (from 320 to 500 ℃), lay-up speed (from 20 to 260 mm/s), consolidation force (from 100 to 600 N), and prepreg tape tension (from 0 to 9 N) on the quality of the resulting laminates manufactured using the laser AFP system were investigated. The interlayer bond strength was characterized using wedge peel tests on samples prepared with different process parameters. The studies were complemented by measurements of the thermal properties of the composites using differential scanning calorimetry. The optimized process parameter windows were determined to be 360 to 400 ℃ for the irradiation temperature, 140 to 160 mm/s for the lay-up speed, 100 N for the consolidation force, and 3 to 5 N for the prepreg tape tension, respectively. The microscopic analysis of the sample cross-sections and peel-damaged surfaces revealed that the different distributions of the resin matrix resulting from the different processing parameters affected the interlayer strength. These results may provide an important reference for manufacturing TPC used in aerospace, defense, and automotive applications.
Lemon peel powder (LPP) obtained after drying (microwave, infrared, and oven) showed the lowest (58.72%) DPPH-radical scavenging activity in oven-dried and the highest (67.84%) in infrared-dried LPP ...while that of fresh lemon peel remained 63.22%. Orange peel powder (OPP) showed the lowest DSA (61.65) after microwave and the lowest (63.54%) after infrared-drying while that of fresh orange peel was 63.48%. Total phenolics were between 114.58 (fresh) and 179.69 mgGAE/100 g (oven) in LPP and between 158.54 (fresh) and 177.92 mgGAE/100 g (infrared) in OPP. The total flavonoid contents were 380.44 (fresh)–1043.04 mg/100 g (oven) in case of LPP and 296.38 (fresh)–850.54 mg/100 g (oven) in case of OPP. The gallic acid contents were 2.39 (fresh)–14.02 mg/100 g (oven) in LPP. The (+)-catechin contents were 1.10 (fresh)–49.57 mg/100 g (oven) for LPP and 0.82 (fresh)–7.63 mg/100 g (infrared) in case of OPP. The oleic acid content was 22.99 (infrared)–58.85% (fresh) in LPP-oil and 28.59 (microwave)–61.65% (fresh) in OPP-oil. The linoleic acid contents were 13.76 (fresh)–36.90% (oven) in LPP-oil and 14.14 (fresh)–37.08% (infrared) in case of OPP-oil. The drying techniques showed profound but variable effects on radical scavenging activity, total phenolics, flavonoid, carotenoids, phenolic compounds and fatty acid composition of both LPP and OPP and oven-drying (60 °C) was the most effective in improving these bioactive constituents.
Apple (Malus×domestica Borkh) has always been considered a fruit with low chlorophyll and carotenoid contents; however these pigments contribute also to the external (peel) and internal (flesh) fruit ...colourations, as well as to the health benefits associated with the regular consumption of this fruit. In the present work we studied the chlorophyll and carotenoid compositions of the peel and flesh of thirteen marketed apple varieties presenting different external colourations (green, yellow and red). All the varieties were characterised by a common pigment profile comprised by chlorophylls a and b, lutein, violaxanthin, neoxanthin, β-carotene, and esterified carotenoids (mainly violaxanthin and neoxanthin) as major compounds. Total pigment content was always higher in the peel (58.72–1510.77μg/g dry wt) than in the flesh (14.80–71.57μg/g dry wt) for each particular cultivar. In general, the green cultivars showed the highest pigment content both in the peel and in the flesh, which were followed in decreasing order by the peel of some red-skinned cultivars and the flesh of the yellow ones. In most cultivars, a characteristic chloroplastic pigment profile was found in the peel, with lutein as the main free carotenoid whilst a chromoplastic profile was usually observed in the flesh, with a prevalence of violaxanthin and neoxanthin and their corresponding acyl esters (mono- and diesters). A correlation between the carotenoid content and the amount of esterified xanthophylls was observed, in particular in the flesh, which reinforce the putative role of the esterification process in the accumulation of these lipophilic compounds within the chromoplasts.
•Chlorophylls and carotenoids were studied in commercial apple varieties.•Chloroplastic pigment concentration was higher in the peel than in the flesh.•Green-skinned cultivars showed the highest pigment content in the peel and flesh.•Total carotenoid and esterified xanthophyll contents were directly correlated.•The degree of xanthophyll esterification was more evident in the flesh.
•A failure parameter prediction model was newly provided for RSW CP samples.•The heterogeneous microstructures and hardness distributions of B1500HS RSWs were characterized using EBSD and ...microhardness tests.•RSW minimum hardness, Hmin, significantly affected RSW mechanical properties. The relationship between the Hmin and LSMP σb values was newly revealed.•For the steels whose σb < 800 MPa, no obvious HAZ softened regions can be observed.
Based on mechanical tests, microstructure characterizations and finite element simulations, the mechanical properties and failure mechanisms of resistance spot welds (RSWs) were investigated in the study. Different types (B1500HS, 340/590DP, 420/780DP and 820/1180DP) and thicknesses (1.2–1.8 mm) of steel plates were welded as coach-peel (CP) samples. To quantify the effect of plate thicknesses on the failure bending moment, MCP, of CP samples, a new parameter, standardized failure bending moment, MSCP = MCP /T1 /T2, was introduced. Based on the new revealed relationship between the MSCP and low strength metal plate tensile strengths (LSMP σb), a MCP prediction model was provided. Moreover, the lap-shear (LS) test data (standardized shear strength, σSS) published in a previous work were also analyzed. With the increment of σb values (<800 MPa), σSS and MSCP parameters increased linearly. When the σb values > 800 MPa, the slopes of σSS and MSCP fitting lines were decreased. The similar variation trends of σSS and MSCP parameters implied similar RSW failure mechanisms. The new revealed relationship between the RSW minimum hardness values (Hmin, measured from base metals or heat affected zones) and LSMP σb values can explain the trends. Finally, by simulations analyses, the effect of different loading conditions on the mechanical performance of RSWs was also studied. CP loads induced the most severe stress concentration near the RSWs, which can severely weaken RSW mechanical performance.
The effect of temperature/humidity (T/H) treatment at 85 ℃/85% relative humidity (R.H.) on the peel strength between screen-printed Ag/polyimide (PI) substrate was evaluated using a 180° peel test. ...Initial peel strength was 22.22 ± 1.00 gf/mm, and then decreased to 0.47 ± 0.22 gf/mm after 500 h at 85 ℃/85% R.H. treatment condition. And, the peeled locus was changed from Ag/PI interface to mixed mode of Ag/PI interface and shallow cohesive inside PI near Ag/PI interface. The decrease in peel strength during T/H treatment is related to formation of weak boundary layer inside PI near Ag/PI interface by hydrolytic degradation of PI due to long-term moisture penetration into the Ag/PI interface.
Graphic abstract
This work scrutinizes the development of activated hydrochar (HC) as a low-cost bio-sorbent for low temperature CO2 capture. Accordingly, rambutan peel (RP) was used as a lignocellulosic precursor to ...produce HC via water-soaking pre-treatment of the biomass followed by hydrothermal carbonization. Then to enhance the microporosity, the developed HC was activated using potassium hydroxide (KOH) at various operating conditions including different activation temperatures (600–900 °C), activation times (60–180 min) and KOH:HC ratios (1:1–4:1). The KOH-activated HC possessed the highest CO2 adsorption capacity (122.37 mg g−1 at 30 °C and 1 atm) when activated using KOH:HC ratio of 2:1 at 850 °C for 120 min with the involvement of water-soaking pre-treatment. Results indicated that water-soaking of biomass prior to the HTC, the HTC process itself and chemical activation of HC could individually enhance the CO2 capture capacity of the resulting adsorbent. Gas selectivity study verified the high affinity of the developed adsorbent towards CO2 compared to other gases such as air, methane and nitrogen. Apart of that, very stable performance of the adsorbent in ten cycles of CO2 adsorption/desorption was demonstrated. Conclusively, the kinetic study proposed that CO2 adsorption mechanism on the adsorbent was governed by physisorption.
Display omitted
•We develop rambutan peel-derived KOH-activated hydrochar for CO2 capture.•Impact of biomass water-soaking and hydrothermal carbonization was discussed.•KOH activation improved the microporosity properties of the hydrochar.•A CO2 adsorption capacity of 122 mg g−1 was attained at ambient condition.•Kinetic study and fast desorption indicate physisorption governs the CO2 adsorption.
•Acid types had a significant effect on the yield of wampee fruit peel pectic polysaccharide (WFPP)•Sugar composition and branches of WFPPs could be modulated by acid types.•Surface morphology and ...main structure of WFPPs was little changed by acid types.•The emulsifying properties of WFPPs were higher than commercial citrus pectin.•WFPP extracted by oxalic, acetic, or hydrochloric acid had better functional properties.
Effects of different extraction acids on physicochemical, structural, and functional properties of wampee fruit peel pectin (WFPP) were comparatively investigated. The hydrochloric acid extracted WFPP (HEP) exhibited the highest degrees of methylation (67.79%) and acetylation (86.29%) coupling with abundant monosaccharides and rhamnogalacturonan branches, but lowest molecular weight (5.58 × 105 Da). The results of SEM, X-ray diffraction, and Fourier transform infrared spectroscopy analyses showed that acid types had little effect on the surface morphology of WFPP. However, compared to commercial citrus pectin (CCP), several specific absorbance peaks (1539, 1019, 920 cm−1) were found in WFPPs, which corresponds to aromatic skeletal stretching, pyranose, and d-glucopyranosyl, respectively. Moreover, the rheological behavior revealed that WFPP solution was pseudoplastic fluid and affected by acid types. And the WFPPs exhibited higher emulsifying activity and emulsion stability than CCP. All these WFPPs presented well antioxidant activity and promoting probiotics ability, especially for HEP.
In this work, different amounts of Lycopersicon esculentum peel extract were used in a low cost, non-toxic green synthesis of tin dioxide nanoparticles. The generated nanoparticles presented the ...following characteristics: Sn-O bond at 666 cm−1; crystalline growth in a purely tetragonal crystal structure; a different size and shape homogeneity, depending on the amount of extract used; and a band gap of around 3.3 eV. Of the generated nanoparticles, the sample with 4% peel extract presented a UV-light photocatalytic degradation rate of methylene blue of around 100% at 120 min; these results are better than those achieved by commercially available tin dioxide nanoparticles.
Display omitted
•Crystal size of the SnO2 NPs was influenced by the amount of extract used.•The materials presented a quasi-spherical morphology.•The variation of the band gap is directly associated with the decrease in the size of the NPs.•Photocatalytic activity presented a MB degradation of 100% within 120 min.
PDF
