Ultra-high molecular weight polyethylene (UHMWPE) with a microporous structure was prepared via thermally induced phase separation (TIPS).Liquid paraffin (LP) was used as a diluent in the preparation of microporous UH...Ultra-high molecular weight polyethylene (UHMWPE) with a microporous structure was prepared via thermally induced phase separation (TIPS).Liquid paraffin (LP) was used as a diluent in the preparation of microporous UHMWPE. Small angle laser light scattering (SALLS) and differential scanning calorimetry (DSC) were used to determine the phase separation temperatures,i.e.the cloud points and the dynamic crystallization temperatures,respectively.It was found that the cloudI points were coincident with the cryst...展开更多
Researches have shown that Raphia hookeri gum could be used as a binder in pharmaceutical formulations and gums in general have been used as emulsifiers in liquid paraffin emulsion but nothing has been heard of Raphia...Researches have shown that Raphia hookeri gum could be used as a binder in pharmaceutical formulations and gums in general have been used as emulsifiers in liquid paraffin emulsion but nothing has been heard of Raphia hookeri in liquid paraffin emulsion as an emulsifier.This work was aimed at evaluating the emulsifying properties of Raphia gum in liquid paraffin emulsion.Two separate preparations containing different concentrations(1,2,3,5 and 10%w/v)of Raphia gum and acacia gum respectively were prepared.Five liquid paraffin emulsions(200 mL each)were also prepared using 60 mL liquid paraffin as the oil phase and 6 g of the various combinations of Raphia gum and Tween 80 as emulsifier blend at ratio 1:5,1:2,1:1,2:1 and 5:1.The preparations were assessed using density,viscosity and stability after 5 days of storage as evaluation parameters.By increasing the concentration of Raphia and Acacia gum,the density of emulsion formed increased.The ranking of the density was 10%>5%>3%>2%>1%.The viscosity of emulsion increased as the concentration of the gum increased.The viscosity which plays a role in the stability of emulsion increased as the concentration of gum increased.The ranking of viscosity was 10%>5%>3%>2%>1%.The stability of the emulsion was measured by the level of creaming and cracking.Emulsion containing 2%w/v of Raphia gum with a creaming index of 23%was more stable compared to the emulsion containing 3%w/v acacia gum with creaming index of 29.9%.The viscosity and stability of emulsion containing emulsifier blends of Raphia and Tween 80 increased with increase in the concentration of Raphia gum.Emulsion containing 3%w/v Raphia gum with no creaming was more stable than emulsion containing 1%w/v emulsifier blend.Raphia gum is suitable for use at a concentration of 2%w/v as an emulsifier in 50 mL of liquid paraffin emulsion competing alternatively to standard acacia gum for emulsification as against Afzelia africana in our previous research which was suitable for use at a concentration of 3%w/v as an emulsifier in 30%v/v liquid paraffin emulsion.展开更多
To improve the tribological behavior of biodiesel soot(BDS) in liquid paraffin(LP), the order of biodiesel soot was increased through thermally oxidized treatment at 500 ℃, and the oil solubility was then improved th...To improve the tribological behavior of biodiesel soot(BDS) in liquid paraffin(LP), the order of biodiesel soot was increased through thermally oxidized treatment at 500 ℃, and the oil solubility was then improved through a modification using oleylamine(OLA). The BDS and thermally oxidized oleylamine-modified BDS(T-BDS-OLA)were characterized through various methods including the use of TG, FETEM, Raman spectroscopy, FTIR, and a zeta potentiometer. The tribological properties and mechanisms of the BDS before and after the thermally oxidized treatment modification were investigated using a ball-on-disc reciprocating tribometer, FESEM, 3 D laser-scanning microscopy, and Raman spectroscopy. The results showed that T-BDS-OLA has a higher degree of order than the BDS, with an onion-like microstructure. BDS and T-BDS-OLA can both improve the antifriction and antiwear properties of LP at a soot content of 0.1%-0.4%, while T-BDS-OLA in LP shows better antifriction and antiwear properties than BDS. The tribological mechanisms can be attributed to both types of soot acting as spacing and roll bearing between the friction surfaces. In addition, the exfoliated graphitic sheets from T-BDS-OLA can form a carbon lubrication layer providing easy sliding.展开更多
Biodiesel soot(BDS) was collected from the combustion of biodiesel using a self-made soot trap. The effect of BDS on the tribological behavior of liquid paraffin(LP) was investigated using a four-ball tribometer. A ro...Biodiesel soot(BDS) was collected from the combustion of biodiesel using a self-made soot trap. The effect of BDS on the tribological behavior of liquid paraffin(LP) was investigated using a four-ball tribometer. A rotating viscometer was used to investigate the effect of BDS on the viscosity of LP. The morphology, composition, and tribological mechanism of BDS were studied by means of FETEM, XRD, XPS, SEM/EDS, and the 3D laser scanning microscopy. Test results showed that the BDS aggregates were chain-like, and the average diameter of BDS was 35 nm. The BDS existed in the form of graphitic layers and amorphous carbon. The oxygen-containing functional groups in BDS consisted of the(C-O-C) and(C-O-H). With an increasing BDS content, the dynamic viscosity of LP increased and the maximum non-seizure load increased initially and became stable later. In addition, the average wear scar diameter(AWSD) of LP increased and the average friction coefficient of LP decreased at first and then increased later. The tribological mechanisms could be ascribed to the variation in content of BDS: BDS could act as a friction modifier for a lower friction coefficient in case of low BDS content. However, the BDS aggregates could lead to increase of abrasive wear to influence the lubricating oil film at higher content of BDS, which would reduce the friction reduction ability and wear resistance of LP.展开更多
Background: Constipation is one of the most common problems in the pediatric age group. In the vast majority, chronic constipation is idiopathic or functional. In addition to education and behavioral changes, disimpac...Background: Constipation is one of the most common problems in the pediatric age group. In the vast majority, chronic constipation is idiopathic or functional. In addition to education and behavioral changes, disimpaction and maintenance treatment with medications are the main pillars of successful outcome. The medications are variably effective and have potential side effects. Objectives: The current clinical trial was designed to evaluate clinical efficacy of polyethylene glycol (PEG) 3350 and liquid paraffin in chronic functional constipation. Besides, subjects were followed carefully for the side effects. Material and Methods: This study was involved 110 children suffering from chronic functional constipation. They were placed into two different groups, randomly. Each group was treated with PEG 3350 or liquid paraffin. The clinical efficacy and side effects were monitored. Results: After disimpaction with bisacodyl suppositories or combined with Mineral oil enemas in hard fecal impaction, maintenance therapy with PEG 3350 or liquid paraffin was started. The treatment duration and efficacies were not different between the two groups. Furthermore, serious adverse drug reaction was not observed. The family history of constipation and presence of incontinence were two worse prognostic factors. Conclusion: No difference was observed between PEG 3350 and liquid paraffin in chronic functional constipation in children in terms of their efficacies. They are safe and effective medications in this age group.展开更多
基金supported by Special Funds for Major State Basic Research Projects,China (No.2003CB615705).
文摘Ultra-high molecular weight polyethylene (UHMWPE) with a microporous structure was prepared via thermally induced phase separation (TIPS).Liquid paraffin (LP) was used as a diluent in the preparation of microporous UHMWPE. Small angle laser light scattering (SALLS) and differential scanning calorimetry (DSC) were used to determine the phase separation temperatures,i.e.the cloud points and the dynamic crystallization temperatures,respectively.It was found that the cloudI points were coincident with the cryst...
文摘Researches have shown that Raphia hookeri gum could be used as a binder in pharmaceutical formulations and gums in general have been used as emulsifiers in liquid paraffin emulsion but nothing has been heard of Raphia hookeri in liquid paraffin emulsion as an emulsifier.This work was aimed at evaluating the emulsifying properties of Raphia gum in liquid paraffin emulsion.Two separate preparations containing different concentrations(1,2,3,5 and 10%w/v)of Raphia gum and acacia gum respectively were prepared.Five liquid paraffin emulsions(200 mL each)were also prepared using 60 mL liquid paraffin as the oil phase and 6 g of the various combinations of Raphia gum and Tween 80 as emulsifier blend at ratio 1:5,1:2,1:1,2:1 and 5:1.The preparations were assessed using density,viscosity and stability after 5 days of storage as evaluation parameters.By increasing the concentration of Raphia and Acacia gum,the density of emulsion formed increased.The ranking of the density was 10%>5%>3%>2%>1%.The viscosity of emulsion increased as the concentration of the gum increased.The viscosity which plays a role in the stability of emulsion increased as the concentration of gum increased.The ranking of viscosity was 10%>5%>3%>2%>1%.The stability of the emulsion was measured by the level of creaming and cracking.Emulsion containing 2%w/v of Raphia gum with a creaming index of 23%was more stable compared to the emulsion containing 3%w/v acacia gum with creaming index of 29.9%.The viscosity and stability of emulsion containing emulsifier blends of Raphia and Tween 80 increased with increase in the concentration of Raphia gum.Emulsion containing 3%w/v Raphia gum with no creaming was more stable than emulsion containing 1%w/v emulsifier blend.Raphia gum is suitable for use at a concentration of 2%w/v as an emulsifier in 50 mL of liquid paraffin emulsion competing alternatively to standard acacia gum for emulsification as against Afzelia africana in our previous research which was suitable for use at a concentration of 3%w/v as an emulsifier in 30%v/v liquid paraffin emulsion.
基金supported by the National Natural Science Foundation of China (Grant No. 51675153)the Major Science and Technology Special Project in Anhui (Grant No. 17030901084)
文摘To improve the tribological behavior of biodiesel soot(BDS) in liquid paraffin(LP), the order of biodiesel soot was increased through thermally oxidized treatment at 500 ℃, and the oil solubility was then improved through a modification using oleylamine(OLA). The BDS and thermally oxidized oleylamine-modified BDS(T-BDS-OLA)were characterized through various methods including the use of TG, FETEM, Raman spectroscopy, FTIR, and a zeta potentiometer. The tribological properties and mechanisms of the BDS before and after the thermally oxidized treatment modification were investigated using a ball-on-disc reciprocating tribometer, FESEM, 3 D laser-scanning microscopy, and Raman spectroscopy. The results showed that T-BDS-OLA has a higher degree of order than the BDS, with an onion-like microstructure. BDS and T-BDS-OLA can both improve the antifriction and antiwear properties of LP at a soot content of 0.1%-0.4%, while T-BDS-OLA in LP shows better antifriction and antiwear properties than BDS. The tribological mechanisms can be attributed to both types of soot acting as spacing and roll bearing between the friction surfaces. In addition, the exfoliated graphitic sheets from T-BDS-OLA can form a carbon lubrication layer providing easy sliding.
基金supported by the National Natural Science Foundation of China (Grant No. 51675153)the Major Science and Technology Special Project in Anhui (Grant No.17030901084)
文摘Biodiesel soot(BDS) was collected from the combustion of biodiesel using a self-made soot trap. The effect of BDS on the tribological behavior of liquid paraffin(LP) was investigated using a four-ball tribometer. A rotating viscometer was used to investigate the effect of BDS on the viscosity of LP. The morphology, composition, and tribological mechanism of BDS were studied by means of FETEM, XRD, XPS, SEM/EDS, and the 3D laser scanning microscopy. Test results showed that the BDS aggregates were chain-like, and the average diameter of BDS was 35 nm. The BDS existed in the form of graphitic layers and amorphous carbon. The oxygen-containing functional groups in BDS consisted of the(C-O-C) and(C-O-H). With an increasing BDS content, the dynamic viscosity of LP increased and the maximum non-seizure load increased initially and became stable later. In addition, the average wear scar diameter(AWSD) of LP increased and the average friction coefficient of LP decreased at first and then increased later. The tribological mechanisms could be ascribed to the variation in content of BDS: BDS could act as a friction modifier for a lower friction coefficient in case of low BDS content. However, the BDS aggregates could lead to increase of abrasive wear to influence the lubricating oil film at higher content of BDS, which would reduce the friction reduction ability and wear resistance of LP.
文摘Background: Constipation is one of the most common problems in the pediatric age group. In the vast majority, chronic constipation is idiopathic or functional. In addition to education and behavioral changes, disimpaction and maintenance treatment with medications are the main pillars of successful outcome. The medications are variably effective and have potential side effects. Objectives: The current clinical trial was designed to evaluate clinical efficacy of polyethylene glycol (PEG) 3350 and liquid paraffin in chronic functional constipation. Besides, subjects were followed carefully for the side effects. Material and Methods: This study was involved 110 children suffering from chronic functional constipation. They were placed into two different groups, randomly. Each group was treated with PEG 3350 or liquid paraffin. The clinical efficacy and side effects were monitored. Results: After disimpaction with bisacodyl suppositories or combined with Mineral oil enemas in hard fecal impaction, maintenance therapy with PEG 3350 or liquid paraffin was started. The treatment duration and efficacies were not different between the two groups. Furthermore, serious adverse drug reaction was not observed. The family history of constipation and presence of incontinence were two worse prognostic factors. Conclusion: No difference was observed between PEG 3350 and liquid paraffin in chronic functional constipation in children in terms of their efficacies. They are safe and effective medications in this age group.