جستجوی مقالات مرتبط با کلیدواژه « additives » در نشریات گروه « پزشکی »

Today pollutants related to refineries and base oil products have caused many concerns about environment. Among these, the share of lubricants as one of the oil products is undeniable for causing environmental problems, harmful pollutants for men and global warming. Recently LCA as a beneficial tool is provided for finding solution to the environmental problems. The aim of this study was to evaluate and compare environmental impacts of lubricants and its ingredients (oil based and additives). Additionally, it was attempted to identify the pollutants caused by the lubricants in order to replace them by environmentally friendly components. In this study, the system boundary was first identified and then the life cycle assessment steps were carried out for vehicle lubricants. Finally, the results were analyzed using SimaPro software based on the Eco Indicator 95. Results showed that although additives made up about 20 percent of the lubricants, more than 80 percent of the environmental pollutants were related to them. These materials have a significant impact on greenhouse gas emission and global warming as 91% of CO2 emission (7.81kg) of lubricants is related to the additives. Also, these materials emit 0.00913 kg C2H4 and 0.0368 kg SPM, which can make summer and winter smog. The car lubricants cause heavy metals (3.95×10-5 kg Pb) to be released into water and release of carcinogenic substances (4.2×10-6 kg B(a)P), which a very low percentage of it is allocated to base oil. The most important environmental pollution of vehicle lubricants was caused by the additives. Since the percentage of each additive to lubricants includes antioxidant (40%), antiwear (23%), detergents (20%) and viscosity modifier (17%), thus, the company must seek to change these types of additives and replace them with the components with lower environmental impact in their production cycles.

Researchers are always looking for ways to maintain the food quality. In this study the effects of two types of packing (Conventional and Vacuum) and additives that contain oregano extract and sodium tripolyphosphate (2%) individually and in combination, were investigated on the quality of rainbow trout fillets without skin during 6 months of storage at -18 ° C.
This survey consisted of five treatments. Sampling were performed at 0 and 1, 2, 3, 4, 5 and 6 months to determine some chemical (thiobarbituric acid, free fatty acid and water holding capacity), sensory and tissue analyses.
Chemical examination of the samples indicated that conventional packing containing sodium tripolyphosphate and additive mixture with oregano had better performance in reducing thiobarbituric acid as well as good effect concerned with vacuum packing in respect of free fatty acids reduction as compared to the control. Dripping in tripolyphosphate treatment was lower than additive mixture. Treatment concerned with sodium tripolyphosphate indicated better results regarding sensory characteristics as compared to the treatment with added oregano extract and control.
The application of polyphosphate as an additive in vacuum packaging might be regarded as an effective method to maintain the quality of rainbow trout fillets stored at -18°C for 6 months.

Acidic sludge is a by-product of used motor-oil reprocessing industries which is disposed of in the environment as hazardous waste material. The polymer bitumen under certain conditions is produced from mixing Bentonite soil, polymer styrene - butadiene – styrene(SBS) and acidic sludge. The aim of this study was retrieval of acidic sludge from polymer bitumen using additives such as bentonite soil and polymer SBS. In this experimental study, the effect of additives with different weight percentages on the performance parameters of bitumen was evaluated. At first, spilled oil phase into the acidic sludge was isolated with centrifugal concentrator. Acidic sludge and additives with a high shear mixer 2500 rpm were mixed together for 30 minutes at 180 °C. Finally, performance tests on acidic sludge and obtained products were performed.The obtained data were analyzed using Excel microsoft 2007. The results indicated that the performance parameters such as softening point temperature, weight loss, penetration degree, PI, Frass breaking point and thermal sensitivity increased from 37 °C, 1/3 %, 230 dmm, -0.07854, -5 °C and 0.0451 to 54 °C, 1%, 130 dmm, 2/7094, -11 °C, 0.02721 respectively. The bentonite soil and SBS polymer in weight percentages of 2 and 4 respectively were the suitable additives in retrieval of acidic sludge from the polymer bitumen.