bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Sintering Temperature and Cooling Rate on the Microstructure and Hardness of Fe-Cr-Mo-V-W-C Sintered Steel added with MoS2
Authors: Songsujaritkul V. , Mahathanabodee S. , Tongsri R. 
Published: December 2020

Abstract
In this work, the Fe-Cr-Mo-V-W-C sintered steels added with MoS2 (1, 3 and 5 wt.%) were produced by powder metallurgy process. The specimens were prepared by mixing, compacting and sintering at temperatures of 1150, 1200 and 1250°C for 45 min in vacuum furnace. After sintering, the specimens were cooled down with N2 at the different cooling rate (0.1 and 5.2°C/s). The density, hardness and microstructure of the sintered Fe-Cr-Mo-V-W-C steels were investigated. The experimental results indicated that the density and hardness of sintered steel could be improved by increase MoS2 addition, cooling rate and sintering temperature. The sintering mechanism was varied from solid state sintering to liquid phase sintering depend on sintering temperatures and MoS2 content. The presence of liquid phases and the increasing of cooling rate resulted in the amount of carbide precipitated decreased in the steel grain but increased precipitation at grain boundaries. The solidified of liquid and eutectic phases were found rising by increased cooling rate. Carbide precipitation in steel grain could be improved by added MoS2 and sintered at low temperature. From the results, it was indicated that the addition of MoS2, increase sintering temperature and cooling rate resulted in the precipitation of carbide, solidified liquid and eutectic phases, and grain growth in the sintered Fe-Cr-Mo-V-W-C steel.
Deterioration of Open-cell Aluminum Foam in Strong Sulfuric Acid
Authors: Sooksaen Pat , Thongyoug Penpisuth 
Published: December 2020

Abstract
Open-cell aluminium foam was fabricated by pressure infiltration and salt leaching method. The processing conditions to obtain uniform interconnected pore structure aluminium foam were melting at 650°C for 1.5 h with the applied pressure of 1.5 bar. Aluminum foams were sectioned into thin pieces to investigate for deterioration behaviour in strong sulfuric acid for 30 days. Significant weight reduction of about 50% was observed when the specimen piece was submersed in 1.0 M H2SO4 in the first three days after which the weight reduction slightly increased to 60%. Al and Cu were the two main elements that had been leached out from the surface of aluminum foam in contact with the acid resulting in the formation of sulfates.
The temperature-dependent structural and optical properties of SrAl2O4-based phosphor
Authors: Loryuenyong V , Kornsawat J , Nakhowong W , Klinjan W , Buasri A 
Published: December 2020

Abstract
This research studied the thermal stability of SrAl2O4 : Eu2+, Dy3+ phosphor for the fabrication of luminescent glasses. The temperature-dependent structural and optical properties of the phosphor were investigated. The results showed that SrAl2O4 : Eu+, Dy3+ phosphor could emit the green light when excited by ultraviolet (UV) light. It was also found that annealing could induce further growth of SrA2O4 crystals, which gave rise to more intense green-light emission. However, at high annealing temperature, the luminescence attained a maximum and started decreasing. An intense luminescence was observed for the SrAl2O4 : Eu2+, Dy3+ phosphor annealed at 750°C. The phosphor degradation at temperatures above 750°C could be because of the formation of secondary phases and the oxidation of the rare-earth atoms that were doped in phosphor. The results showed that, with proper fabrication processes, phosphors could be considered as promising materials for various applications.
Kinetic study for the co-pyrolysis of water hyacinth biomass with waste polystyrene
Authors: Phiwchaaum C , Ksapabutr B , Chaiyut N , Panapoy M 
Published: December 2020

Abstract
Co-pyrolysis behavior of water hyacinth (WHC) and waste PS using thermogravimetric analysis to determine kinetic parameters was investigated. TG and DTG results indicated that the pyrolysis of WHC and mixture of WHC and waste PS could be divided into three stages. It was found that co-pyrolysis of WHC and waste PS delayed the pyrolysis process with a wider decomposition temperature range, when compared with the pyrolysis of PS. The results compared with the pyrolysis of individual components revealed a positive synergistic interaction between WHC and waste PS according to the difference in weight loss. Coats-Redfern method was applied in the second stage to evaluate the activation energy (Ea) and pre-exponential factor (A) from the data of weight loss using three major reaction mechanisms. Two conversion temperature zones, zone I of 240-400 °C and zone II of 400-530 °C, were identified and a best-fit model describing the co-pyrolysis behavior of mixture was achieved. The addition of waste PS to WHC led to a slight decrease in the activation energy in the first zone and then the activation energy significantly reduced in the second zone. Chemical reaction and diffusion-controlled reaction mechanisms could be kinetically examined and enabled good explanation of the co-pyrolysis behavior of the mixture of WHC and waste PS as well as individual pyrolysis.
Mechanical properties and foaming behavior of Poly(lactic acid) blend Polybutylene Succinate
Authors: Bualuang W. , Threepopnatkul P. , Sittattrakul A. 
Published: December 2020

Abstract
The extensive use of non-biodegradable plastics has been causing serious environmental pollutions because of the degradability issue from especially consumable food packaging. In this research, biodegradable materials i.e., Poly(lactic acid) (PLA) and Polybutylene succinate (PBS) are chosen for the study. PLA/PBS foam was prepared using Azodicarbonamide (ADC) and Poly(ethylene glycol) (PEG) 20 wt% as a blowing agent and plasticizer, respectively. Foamability of different content PLA/PBS blend were investigated. PLA/PBS foam were characterized by Water absorption, Flexural testing, Scanning Electron Microscope (SEM). Flexural properties of PLA/PBS foam (70/30) showed the highest flexural modulus of 384 MPa due to the smallest cell size while PLA/PBS foam (20:80) showed the highest flexural stress of 11 MPa. PLA/PBS foam showed uniform cell size distribution. PLA/PBS foam had water absorption ability due to its porous structure.
Effect of Glycerol on Gluten filled in Natural Rubber/WG Blend
Authors: Thongpin C , Wongprat C , Srithavorn P , Muenchee P 
Published: December 2020

Abstract
In recently, a large number of utilization of NR has been found in several applications such as foam, insole but they do not provide good properties. In order to improve mechanical properties, in this work, wheat gluten (WG) which is a complex protein derived from wheat was used as a reinforcement. Furthermore, NR with WG (plasticized WG) can reduce costs of materials and easily degrade. NR-WG blend was prepared by mixed NR and WG, plasticized by glycerol, then mixed each other by using two rolls mill and compressed to get specimens. SEM, MDR, tensile testing and tear testing were used to characterize compounds. The effect of glycerol contents added and acting as plasticizer were also studied. The results show that the presence of glycerol also affected vulcanization behavior of rubber matrix. The increasing of glycerol content can also improve dispersion of WG in rubber matrix and indeed improve mechanical properties of NR.
Physicochemical, physical characteristics and antioxidant activities of three edible red seaweeds (Kappaphycus alvarezii, Eucheuma spinosum and Eucheuma striatum) from Sabah, Malaysia
Authors: Farah Nurshahida M S , Nazikussabah Z , Subramaniam S , Wan Faizal W I , Nurul Aini M A 
Published: December 2020

Abstract

Kappaphycus alvarezii (KA), Eucheuma spinosum (ESp) and Eucheuma striatum (Est are tropical red seaweeds taken from Kunak, Sabah, contain essentials source of bioactive compounds to produce variety of functional foods. This study was intended to investigate the physicochemical, physical properties and antioxidant activities related to these edible seaweeds. Physicochemical properties value of swelling capacity (SWC) and oil retention capacity (ORC) in KA species showed the highest value (p<0.05) compared to ESp and ESt, and water retention capacity (WRC) in ESp species was significantly different than KA and ESt (p<0.05). As in physical properties, ESp exhibited higher in moisture content and opacity than KA and ESt. KA showed the highest water solubility (p<0.05) which associated to its carrageenan compound. The antioxidant activities; DPPH and TEAC assay with total phenolic content (TPC) of three seaweed species indicated that KA displayed the highest TPC (19.17±0.04 mg GAE/g DW) and the lowest radical scavenging activity in both TEAC and DPPH assays. Hence, the findings disclose the physical and physiochemical properties and antioxidant values of these seaweeds application as new information and potential antioxidant sources in foods manufacturing commodities.
Beneficial effects of spontaneous fermentation in enhancing the phenolic contents, antioxidant activity and cultivation of lactic acid bacteria of Carica papaya leaf
Authors: So’aib M S , Hamid K H K , Salihon J , Tan H L , Hamid A. 
Published: December 2020

Abstract
Spontaneous fermentation using endogenous microorganisms is a reliable method for enhancing the bioactivity of medicinal plant. Here, the method was applied on Carica papaya leaf (CPL) for the first time to enhance the phenolic contents, antioxidant activity, and cultivation lactic acid bacteria. The antioxidant activity was estimated in terms of 2,2-diphenyl-1-picryl-hydrazyl-hydrate DPPH scavenging activity. Meanwhile, the microorganism fingerprinting was carried out by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) method. Total phenolic content and antioxidant activity of fermented CPL (day 90) were 45.64±0.69 mg GAE/g dm and 467.38±4.09 mM TE/g dm, respectively, higher than 12.13±0.69 mg GAE/g dm and 275.46±3.09 mM TE/g dm, respectively of control, unfermented CPL. The cultivation of lactic acid bacteria (LAB) was marked by its viable cell counts between 103 to 107 colony forming unit (CFU)/mL on De Man, Rogosa and Sharpe (MRS) agar medium and the fingerprints of Weisella, Lactobacillus and Lactococcus species on PCR-DGGE throughout the fermentation period.
Extraction of Kaffir Lime (Citrus hystrix
DC.) essential oil by steam distillation and evaluation of chemical constituents
Authors: Quyen N T C , Ngan T T K , Phong H X , Hien T T , Dung L T 
Published: December 2020

Abstract

Citrus hystrix which is commonly known as Kaffir Lime, is a plant with great potential for research and commercialization. C. hystrix essential oil is used as a fragrance to increase appetite in food, or sweet-smelling in cosmetics and antibacterial properties in the health field. Most research have focused on the peels, yet the EO content in C. hystrix leaves is also noteworthy. There are many essential oils extraction methods from conventional to advanced techniques. However, it is necessary to consider the influence of heat during heat transfer to constituents in materials, which easily decompose the volatile compounds contained in the essential oil. Steam distillation method can limit this disadvantage by separating the solvents and materials into two places that are only connected by a steam pipe. In this study, the steam distillation method was employed to extract the EOs from C. hystrix leaves. The chemical components in this EOs was evaluated by gas chromatography–mass spectrometry (GC-MS) method. C. hystrix leaves achieved an essential oil yield of 1.24%. Moreover, different compounds in Kaffir Lime EOs obtained from steam distillation method were identified, including β-citronellol, citronellyl acetate, linalool, caryophyllene, pinene, sabinene, and naphthalene. Findings from the present study provide helpful insights to effective essential oil extraction from C. hystrix leaves with high content of valuable phytochemical compounds.
Phytochemical screening and antioxidant potential of crude drug “Cao Khai” in Ninh Thuan Province, Vietnam
Authors: Nguyen N Q , Pham T N , Nguyen V T , Nguyen M T , Dung L T , Bach L G 
Published: December 2020

Abstract
For a long time, the ethnic minorities in Ninh Thuan province, Vietnam have mixed Coptosapelta tomentosa Rubiaceae with other types of medicinal herbs to create an esoteric remedy called “Cao Khai”. This study had provided scientific evidence on phytochemical screening and antioxidant potentials of diethyl ether, ethanol and aqueous extracts of “Cao Khai”. Phytochemical screening of crude “Cao Khai” extracts showed the presence of mutiple components such as saponins, flavonoids, volatile oils, triterpenoids, organic acids, anthraquinon, coumarin, reducing compounds and polyuronid. The polyphenols and flavonoids content were determined using gallic acid and quercetin as a standard, respectively. 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and 2,2′–azino–bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) methods were used to measure free radical scavenging capacity. Results have shown that the total polyphenol and flavonoids content achieved 49.67 ± 0.35 µgGAE/mg and 5.49 ± 0.84 μgQE/mg, respectively. “Cao Khai” had low IC50 values of 126.06 ± 1.33 µg/mL (DPPH) and 35.4 ± 0.74 µg/mL (ABTS), which indicated that the crude drug “Cao Khai” illustrated significant free radical scavenging activity in a dose-dependent manner, as compared to ascorbic acid.
Antioxidant activity, total phenolics and flavonoids contents of Pandanus amaryllifolius (Roxb.)
Authors: Quyen N T C , Quyen N T N , Nhan L T H , Toan T Q 
Published: December 2020

Abstract

Pandanus amaryllifolius Roxb. was commonly used in Vietnam as a fragrance because of its aroma. These aromatic plants are the primary source of medicinal herbs because of their valuable biological activities. This study was aimed at determining the phytochemical content, Total flavonoids contents (TFC), total phenolic content (TPC) and antioxidants were analyzed by Folin-Ciocalteu and DPPH scavenging assays, respectively. The total flavonoid content is measured by the aluminum chloride method. The qualitative phytochemical analysis confirmed the presence of flavonoids, terpenoids, coumarin, and reducing sugar, which is chemical components in Pandanus amaryllifolius Roxb extract. Results showed that ethanol extract exhibited higher DPPH (129.327 ug/ml) and TPC (38.12 mgGAE/DW) activity than water extraction (265.738 ug/ml and 10.97 mgGAE/DW). Research shows that using this plant more in pharmaceuticals or food should be focused and developed.
Phytochemical screening of Allium Tuberosum Rottler. ex Spreng as food spice
Authors: Nhut P T , An T N T , Minh L V , Truc T T , Anh N H T 
Published: December 2020

Abstract
In Vietnam, Allium Tuberosum Rottler. ex Spreng (ATRES) was used in everyday meals as a seasoning, and as a common remedy for the prevention of diarrhea, asthma, and so on. In this study, We evaluated the phytochemical composition, total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity of ATRES, which was harverted in Vietnam. The findings indicate that Vietnamese ATRES had a varied range of pharmacologically active compounds, including alkaloid, flavonoid, terpenoid, tannin, coumarin, saponin, and reduced sugar. Folin-Ciocalteu calculates the TPC and the TFC is derived using the aluminum chloride method. The TPC and TFC of ethanol extract in ATRES achieved 46.15 ± 1.26 mgGAE/g DW and 31.10 ± 1.12 mg QE/g DW, respectively. Taken together, we found that the antioxidant capacity in DPPH forms (2, 2-diphenyl-1-picrylhydrazyl) was assessed by spectrophotometric method and obtained an IC50 result of 97.46 µg/ml. These results indicate that Vietnamese ATRES is effective in increasing food use with its antioxidant and valuable activity.
Phytochemical Content and Antioxidant activity in aqueous and ethanolic extracts of Eryngium foetidum L.
Authors: Thi N Q N , An T N T , Nguyen O B , Dung L T , Minh L V , Nhan L T H 
Published: December 2020

Abstract

Eryngium foetidum L. has been used as a spice for food and treatment for diabetes, rheumatism, anti-inflammatories, respiratory and stomach disorders. In Vietnam, due to high consumption of Eryngium foetidum L. in popular dishes and its significant benefits, the preliminary screening of the plant phytochemicals is required to extend its application and improve efficacy. The present research aimed at Eryngium foetidum L. extraction using aqueous and ethanolic as solvents to explore their phytochemical composition, total contents of flavonoids and phenolics and antioxidant activity. Phytochemical screening has detected the presence of flavonoids, tannins, alkaloids and terpenoids in both plant extracts. In addition, the total content of phenolics in both extract was equally significant while the total content of flavonoids was higher in ethanolic extract, as compared to the aquaeous extract. The antioxidant actions of aquaeous and ethanolic extracts were estimated using DPPH and ABTS scavenging assays. Results have shown that the former exhibited stronger DPPH scavenging activity than the latter. Findings from the present study suggested that ethanol and water can be useful for Eryngium foetidum L. extraction with high content of phytochemicals, phenolics and antioxidant activity.
Bioactive Compounds and Antioxidant Activity of Leaves from Piper sarmentosum Piperaceae
Authors: Nguyen N Q , Nguyen V T , Van N T H , Vo T N M 
Published: December 2020

Abstract

Piper sarmentosum belongs to Piperaceae family, which is used as a cuisine in many Southeast Asian. This is a valuable herbal plant used as a traditional treatment for headaches, coughs, asthma, fever and as a spice in everyday cooking. The plant plays an important role in the antioxidant application. This study was conducted to analyze qualitative phytochemicals and assess the free radical potential, total polyphenol and flavonoid content of Piper sarmentosum leaves extracts. Using the standard procedure, the crude extracts were proved having lots phytochemicals such as alkaloids, coumarin, flavonoids, reducing compounds, saponins, tannins and terpenoids. The ethanolic extract from leaves of Piper
sarmentosum had a medium total polyphenols content (60.61 ± 0.96 µgGAE/mg) and flavonoid content (70.14 ± 0.38 µgQE/mg). DPPH and ABTS radical scavenging activity increased proportionally with the concentration of Piper
sarmentosum. IC50 value of ethanolic extract were 264.20 ± 17.90 μg/mL (DPPH) and 176.40 ± 8.62 μg/mL (ABTS), respectively. The leaves of Piper sarmentosum can be used in the battle against diseases induced by free radicals such as asthma, diabetes mellitus, and coronary artery disease as a natural supply of antioxidants.
Phytochemical Screening, Antioxidant Activities, Total Phenolics and Flavonoids content of Leaves from Persicaria
odorata Polygonaceae
Authors: Nguyen V T , Nguyen M T , Nguyen N Q , Truc T T 
Published: December 2020

Abstract

Persicaria
odorata Polygonaceae is a widely used herb in Asia. It contains several interesting bioactive components, and possesses properties that promote health. This is an important medicinal plant used to treat inflammation and swelling, diarrhea and excessive bleeding, and so on. Base on phytochemical analysis, the Persicaria
odorata leaves contained lots compounds such as alkaloids, tannins, anthraquinone, flavonoids, terpenoids, coumarins, saponins and reducing compounds. The presence of those phytochemicals in this herbs indicated its potential medicinal effects, along with various vital biological and physiological properties. The leaves were extracted using ethanol and water to produce the respective extracts. The total phenolic and flavonoids content of each extract were determined by the Folin-Ciocalteu method and the aluminum chloride reagent, respectively. The ethanolic extract from leaves of Persicaria
odorata showed higher total phenolic (58.56 ± 3.86 µgGAE/mg) and flavonoid contents (70.65 ± 4.14 µgQE/mg) than the aqueous extract. The percentage of radical scavenging activity was determined using radical scavenging assay with DPPH and ABTS. The ethanol extract of Persicaria
odorata leaves had a high antioxidant activity with an IC50 of 311.26 ± 3.06 µg/mL DPPH and 167.66 ± 6.67 ABTS. The presence study showed that in ethanolic and aqueous extracts the medicinal potential of Persicaria odorata leaves and the positive relation between the total content of polyphenols and antioxidant activities.
Effect of Wet Milling and Purification Process on Yield and Color of Jackfruit Seed Starch
Authors: Thanh V T , Khang V C , Nhan N P T , Nguyen D T , Nhi T T B , Quoc N T 
Published: December 2020

Abstract
Jackfruit is a common fruit, which grows in Asian areas, including Thailand, India, China and Vietnam. Jackfruit seeds are a by-product of the food industry, and are typically ignored as a source of nutrients in the human diet given their possible application.. Starch production is a conventional ways to take advantage of this by-product source. The wet milling and purification process are the two main processes for extracting and improving the color of starch. Therefore, this research aims to determine the impact of wet milling and purification process on yield and color of starch as well as evaluate some parameters of physicochemical properties in jackfruit seed starch. In this study, the ratio of jackfruit seed:water (1:1, 1:2, 1:3, 1:4 and 1:5) and the time of wet milling (1, 2, 3, 4 and 5 min) are investigated. Three main factors observed in the purification process were the type of solvent (water and ethanol), solvent ratio (1:2, 1:4, 1:6 and 1:8) and the number of purification (1, 2, 3, 4 and 5 times). The result revealed that the ratio of jackfruit seed : water reached the highest starch yield was 1:3 (32.11±1.06%, db) and the time achieved 3 min (40.77±1.25%, db). The selected solvent for purification of starch was ethanol with the ratio of sample : water was 1:4 and the number of purification was two times for the best color. Some of characteristic nutrition values was evaluated, including %protein: 3.8, %ash: 0.08, %carbohydrate 86.99 and %lipid 0.20). The water solubility index and viscosity of starch were contradictory. When the temperature increased, the viscosity of starch decreased but the solubility index increased. Jackfruit seed starch was spherical or semi-oval which was presented by SEM (Scanning Electron Microscope) method.
The influence of drying temperature on the quality, morphology and drying characteristics of Cosmos caudatus
Authors: Latiff N A , Abdullah L C , Ong P Y , Embi K , Malek S A 
Published: December 2020

AbstractThis study scrutinizes the influence of oven drying temperature (40, 60, and 80 °C) on the product quality (phenolic content and antioxidant activity), morphological appearance, and drying characteristics ofCosmos caudatus (C. caudatus).A spectroscopic UV assay and a Field emission scanning electron microscope (FESEM) were used to analyse the product quality and the morphological appearance of theC. caudatusleaves. The drying characteristics were assessed based on the pattern from the drying curve (moisture ratio versus drying time) at the tested temperatures. It was observed that a drying temperature of 40 °C preserved the quality of the driedC. caudatusleaves. This may be seen where a significant reduction of the phenolic content and antioxidant activity occurred at 60 to 80 °C, probably due to the decomposition of the valuable phytochemical compounds. This effect correlated with the physical damage that took place to the vegetal tissues. The damage was recorded as 40 < 60 < 80 °C according to the severity (from minor to severe damage). The drying process ofC. caudatusoccurred mainly in the falling rate period, in the absence of an initial rate period. Higher drying temperatures resulted in a shorter drying time as proven by the value of the effective moisture diffusivity that increased from 4.12 × 10−12m2/s (40 °C) to 24.71 × 10−12m2/s (80 °C). TheC. caudatussample dried with an oven dryer at 40 °C possessed the best condition of drying without compromising the quality of the driedC. caudatusleaves.