Influence of pre-treatment in citric acid solution on physical and mechanical properties of thermally compressed oil palm board

Oil palm trunk is an excellent raw material for thermally compressed wood board.However,improvements to dimensional stability during water absorption and reduced thickness swelling has been tied to losses in other mechanical properties,especially as the compression temperature is increased.Toward solving this trade-off,we analyzed the effects of a 48 h pre-soak in citric acid solutions(0,5,15,25,or 35%w/v in distilled water)on the physical and mechanical properties of oil palm board compressed at 140℃.The reference benchmark case was compressed at 200℃without pretreatment.The oil palm board raw materials were obtained from outer,middle and inner parts of trunk.The results showed that the oven-dry density of compressed oil palm board made from different parts of trunk increased with thermal compression(maximum pressure 12.26 MPa for 8 min).The citric acid pretreatment improved water absorption and thickness swelling properties of oil palm board thermally compressed at 140℃,consistent with the citric acid concentration.The carboxyl groups in citric acid cross-link with the hydroxyl groups in the wood.However,no significant difference was found between the benchmark(200℃)and pretreatments with 5 or 15%citric acid.The citric acid altered the wood chemistry during hot compressing at 140℃.Static bending strength,modulus of rupture(MOR),and modulus of elasticity(MOE)slightly decreased with the citric acid pretreatment,matching the effects of high temperature compression at 200℃.

Combined Effect of Garlic Juice and Sa-Tay Marinade on Quality Changes of Oyster Meat during Chilled Storage

Traditionally, meat has been marinated to improve yield, flavor, tenderness, and may increase product shelf life. Sa-tay is a popular dish in Thai restaurant. Physical, chemical, microbiological and sensory qualities after the oyster meat treated with garlic 0, 2 ml of garlic juice then marinated with Sa-tay condiment (8%, wt/wt) were monitored during chilled storage, 4℃ ± 2℃. pH and glycogen content of all treatments decreased while TVB, lactic acid content, ammonia content and K-value increased as storage time. A TBARS, rancidity indicator, of the control was higher compared with other treatments. Mesophilic and lactic acid bacteria of all treatments particularly the oyster treated with the juice increased as storage time increased. However, psychrophilic bacteria, coliforms, fecal coliforms, Escherichia coli, Staphylococcus aureus, Salmonella spp. and Vibrio spp. were low throughout the storage. Consumer acceptability scores of all treatments were higher than borderline (>5) at the end of the storage, 12 days.

Effect of Lipids and Thermal Processing on Antioxidant Activities of Tested Antioxidants and Tom-Kha Paste Extract

The effect of lipids on antioxidant activities of tested antioxidants and Tom-Kha paste extract was determined in the food system. 2,2’-diphenyl-1-picrylhydrazyl (DPPH), 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) scavenging activity, peroxide value (PV), thiobarbituric acid reactive substances (TBARS) and p-anisidine value (AV) were methods for determining. The result showed that heating at 121°C for 15 min caused decreasing on DPPH scavenging activity of lauric acid but didn’t affect ABTS scavenging activity of both lauric acid and virgin coconut oil. DPPH scavenging activity of all mixtures was significantly decreased (p p-hydroxycinnamic acid and Tom-Kha paste extract in both lauric acid and virgin coconut oil systems increased after thermal processing. In food systems of lauric acid, PV of almost mixtures except lauric acid-Tom-Kha paste extract 2:1 and lauric acid-Trolox 15:1 was increased after heating. TBARS value of the mixtures was not significantly different (p?≥ 0.05) after thermal processing. AV of only lauric acid-gallic was enhanced after heating. PV of virgin coconut oil added with all tested antioxidant was not changed after heating. TBARS of virgin coconut oil added with antioxidant samples seemed to slightly increase after heating. AV of virgin coconut oil with added gallic acid and Tom-Kha paste extract were not changed by heat treatment while AV of virgin coconut oil with added p-hydroxycinnamic acid and Trolox seemed to decrease after heating.

Potential use of nanofiltration like-forward osmosis membranes for copper ion removal

The discharge of industrial effluent containing heavy metal ions would cause water pollution if such effluent is not properly treated.In this work,the performance of emerging nanofiltration(NF)like-forward osmosis(FO)membrane was evaluated for its efficiency to remove copper ion from water.Conventionally,copper ion is removed from aqueous solution via adsorption and/or ion-exchange method.The engineered osmosis method as proposed in this work considered four commercial NF membranes(i.e.,NF90,DK,NDX and PFO)where their separation performances were accessed using synthetic water sample containing 100 mg·L-1 copper ion under FO and pressure retarded osmosis(PRO)orientation.The findings indicated that all membranes could achieve almost complete removal of copper regardless of membrane orientation without applying external driving force.The high removal rates were in good agreement with the outcomes of the membranes tested under pressuredriven mode at 1 MPa.The use of appropriate salts as draw solutes enabled the NF membranes to be employed in engineered osmosis process,achieving a relatively low reverse solute flux.The findings showed that the best performing membrane is PFO membrane in which it achieved N 99.4%copper rejection with very minimum reverse solute flux of<1 g·m-2·h-1.

过热浆铸7075铝合金的阳极氧化工艺参数（英文）

通过对过热浆铸7075铝合金基体阳极氧化工艺参数包括电压、电流密度、温度和电解液的选择,确定合适的阳极氧化工艺参数。该合金阳极氧化所用溶液为硫酸电解液、硫酸与硼酸或柠檬酸的混合液。阳极氧化所用电压为15~30V,测试电流密度为2和3A/dm^2,温度为5和15℃。测试氧化膜的厚度、表面形貌、硬度和耐腐蚀性。结果发现,该合金在硫酸溶液中阳极氧化的最佳参数为25 V、2A/dm^2和5℃。此条件下形成的氧化膜表面光滑且厚度均一、孔隙率低、硬度高,且具有最优的耐腐蚀性。然而,在较高温度(15℃)下进行阳极氧化时,可以观察到不连续的氧化膜。所用替代电解质是硫酸与硼酸或柠檬酸的混合溶液。结果表明,硼酸和柠檬酸电解液均能提高氧化膜的厚度、硬度、耐蚀性和品质。但是,这些氧化膜的性能仍然比不上合金在硫酸电解液中低温下(25 V,2A/dm^2,5℃)形成的氧化膜的性能。

Barium Titanate-reinforced Acrylonitrile-Butadiene Rubber: Synergy Effect of Carbon-based Secondary Filler

Acrylonitrile rubber(NBR)composites filled with barium titanate(BT)were prepared using an internal mixer and a two-roll mill.Also,a secondary filler,namely carbon nanotubes(CNT),was added in order to find a potential synergistic blend ratio of BT and CNT.The cure characteristics,tensile and dielectric properties(dielectric constant and dielectric loss)of the composites were determined.It was found that NBR/BT composites with CNT secondary filler,at a proper BT:CNT ratio,exhibited shorter scorch time(ts1)and cure time(tc90)together with superior tensile properties and reinforcement efficiency,relative to the one with only the primary filler.In addition,the NBR/BT-CNT composite with 80 phr BT and 1–2 phr CNT had dielectric constant of 100–500,dielectric loss of 12–100 and electrical conductivity below 10−4 S/m together with high thermal stability.Thus,with a proper BT:CNT mix and filler loading,we can produce mechanically superior rubber composites that are easy to process and low-cost,for flexible dielectric materials application.