摘要 :
This work demonstrates on the example of antioxidants and their degradation products that the knowledge about degradation mechanisms of additives gained from MS studies can be used to design and (re)formulate lubricants for long-t...
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This work demonstrates on the example of antioxidants and their degradation products that the knowledge about degradation mechanisms of additives gained from MS studies can be used to design and (re)formulate lubricants for long-term applications in the future. Additionally, LC-MS offers the possibility of specific monitoring of individual additives in fully formulated or altered lubricants.
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摘要 :
The species of lubricant additives expanded along with the development of technology, extending from natural minerals to synthetic compounds Advancements in technologies and production capabilities have allowed for size controlled...
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The species of lubricant additives expanded along with the development of technology, extending from natural minerals to synthetic compounds Advancements in technologies and production capabilities have allowed for size controlled differentiation from a large micron scale to nanoparticles. Meanwhile, the performance improves with finer particles, especially for anti-wear properties. With the encouragement of clean and environmentally friendly additives, ZDDP and other anti-wear agents are constantly being replaced because of its environmental hazards, the researchers turn to the environment-friendly and more efficient anti-wear additives. Serpentine, as a natural mineral, has been widely studied since it was found to be used as lubricant additives. However, the complex composition of natural minerals brings difficulties to explain its specific anti-wear mechanism. As the main component of serpentine, magnesium silicate hydrate was synthesized and added into the base oil for better tribological properties In this work we prepare modified magnesium silicate hydroxide (MSH) and compare the tribological performances as lubricant additives between synthetic MSH and serpentine mineral under different experiment conditions, such as load, speed.
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摘要 :
The species of lubricant additives expanded along with the development of technology, extending from natural minerals to synthetic compounds Advancements in technologies and production capabilities have allowed for size controlled...
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The species of lubricant additives expanded along with the development of technology, extending from natural minerals to synthetic compounds Advancements in technologies and production capabilities have allowed for size controlled differentiation from a large micron scale to nanoparticles. Meanwhile, the performance improves with finer particles, especially for anti-wear properties. With the encouragement of clean and environmentally friendly additives, ZDDP and other anti-wear agents are constantly being replaced because of its environmental hazards, the researchers turn to the environment-friendly and more efficient anti-wear additives. Serpentine, as a natural mineral, has been widely studied since it was found to be used as lubricant additives. However, the complex composition of natural minerals brings difficulties to explain its specific anti-wear mechanism. As the main component of serpentine, magnesium silicate hydrate was synthesized and added into the base oil for better tribological properties In this work we prepare modified magnesium silicate hydroxide (MSH) and compare the tribological performances as lubricant additives between synthetic MSH and serpentine mineral under different experiment conditions, such as load, speed.
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摘要 :
Automotive crankcase lubricants can be formulated to give further improved tribological performances by choice of base oil slate and adjustment to base oil blend composition -complementing advances in extending lubricant performan...
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Automotive crankcase lubricants can be formulated to give further improved tribological performances by choice of base oil slate and adjustment to base oil blend composition -complementing advances in extending lubricant performances to meet requirements of next generation lubricant specifications normally achieved by the development of new additive or base oil technology and by reformulation strategies employing existing technologies. Base fluids within the same API group classifications have been shown to influence the growth rates and thicknesses of antiwear films where a near-parabolic variation with the blend ratio is exhibited, and where the choice of processing slate ultimately determines inversions to this response. Individual ZDDP types behave differently to these variations and their responses can be dominant, or weak, when mixed or in a fully-formulated lubricant system. Both allow new formulation methods and a novel avenue to control individual antiwear components in a lubricant. In this work, the antiwear films of fully formulated lubricants subjected to the API SM and ILSAC GF-4 Sequence ⅢG high temperature oxidation engine test are mapped over their degradation life to reveal base fluid influences on the retention of antiwear performance. Statistical analyses on ZDDP base oil responses thought to be governed by "base fluid-additive type" mechanisms show that these behaviour correlate to (i) base fluid physical-chemical properties, (ii) composition of base fluid molecular structures, and (iii) valve train wear results of Sequence IIIG engine tests.
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摘要 :
Automotive crankcase lubricants can be formulated to give further improved tribological performances by choice of base oil slate and adjustment to base oil blend composition - complementing advances in extending lubricant performa...
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Automotive crankcase lubricants can be formulated to give further improved tribological performances by choice of base oil slate and adjustment to base oil blend composition - complementing advances in extending lubricant performances to meet requirements of next generation lubricant specifications normally achieved by the development of new additive or base oil technology and by reformulation strategies employing existing technologies. Base fluids within the same API group classifications have been shown to influence the growth rates and thicknesses of antiwear films where a near-parabolic variation with the blend ratio is exhibited, and where the choice of processing slate ultimately determines inversions to this response. Individual ZDDP types behave differently to these variations and their responses can be dominant, or weak, when mixed or in a fully-formulated lubricant system. Both allow new formulation methods and a novel avenue to control individual antiwear components in a lubricant. In this work, the antiwear films of fully formulated lubricants subjected to the API SM and ILSAC GF-4 Sequence IIIG high temperature oxidation engine test are mapped over their degradation life to reveal base fluid influences on the retention of antiwear performance. Statistical analyses on ZDDP base oil responses thought to be governed by "base fluid-additive type" mechanisms show that these behaviour correlate to (i) base fluid physical-chemical properties, (ii) composition of base fluid molecular structures, and (iii) valve train wear results of Sequence IIIG engine tests.
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In the early nineties, new techniques for strengthening of older concrete civil engineering structures were developed at Essen University in cooperation with German construction companies. The new strengthening techniques are: add...
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In the early nineties, new techniques for strengthening of older concrete civil engineering structures were developed at Essen University in cooperation with German construction companies. The new strengthening techniques are: additional compres-sive zone and additional reinforcement in grooves. Furthermore, a design concept of strengthening bridge superstructures with additional prestressing was developed. Details of design and construction of the strengthening techniques are presented. Case studies will also be shown, in order to demonstrate the experiences made to date.
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摘要 :
In the early nineties, new techniques for strengthening of older concrete civil engineering structures were developed at Essen University in cooperation with German construction companies. The new strengthening techniques are: add...
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In the early nineties, new techniques for strengthening of older concrete civil engineering structures were developed at Essen University in cooperation with German construction companies. The new strengthening techniques are: additional compres-sive zone and additional reinforcement in grooves. Furthermore, a design concept of strengthening bridge superstructures with additional prestressing was developed. Details of design and construction of the strengthening techniques are presented. Case studies will also be shown, in order to demonstrate the experiences made to date.
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摘要 :
First the fretting wear behavior of CuS nanoparticles additives in grease were studied. The results show that the fretting wear volume reduce significantly when CuS nanoparticles additives add to grease. At the same time the exist...
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First the fretting wear behavior of CuS nanoparticles additives in grease were studied. The results show that the fretting wear volume reduce significantly when CuS nanoparticles additives add to grease. At the same time the existence of sulfid nanoparticles can reduce friction coefficient at the latter fretting time. The results of XPS tests show that Cu, Zn, Ni, S and B elements were founded in the film of wear scar. Secondly the effect of antiwear and oiliness additives on fretting wear behavior of nanoparticles additives in Grease were studied. It was found that when some antiwear, oiliness additives (such as T_(203), T_(322), stearyl alcohol or stearic acid) and sulfide nanoparticles were added to urea grease, a synergy effect between the two types of additives made fretting wear volume more small than that of either additive. Based on the results of contrast experiment and some analysis of fretting wear scars, we present the idea that two additives react with friction surface step by step. That is to say, the high chemical activity of CuS nanoparticles decompose first and form protective layer, the heat converted from chemical reaction of CuS decomposition and mechanical motion promote composition of common oil additives, thus protective layer is formed once again and wear volume further decrease.
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摘要 :
First the fretting wear behavior of CuS nanoparticles additives in grease were studied. The results show that the fretting wear volume reduce significantly when CuS nanoparticles additives add to grease. At the same time the exist...
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First the fretting wear behavior of CuS nanoparticles additives in grease were studied. The results show that the fretting wear volume reduce significantly when CuS nanoparticles additives add to grease. At the same time the existence of sulfid nanoparticles can reduce friction coefficient at the latter fretting time. The results of XPS tests show that Cu, Zn, Ni, S and B elements were founded in the film of wear scar. Secondly the effect of antiwear and oiliness additives on fretting wear behavior of nanoparticles additives in Grease were studied. It was found that when some antiwear, oiliness additives (such as T_(203), T_(322), stearyl alcohol or stearic acid) and sulfide nanoparticles were added to urea grease, a synergy effect between the two types of additives made fretting wear volume more small than that of either additive. Based on the results of contrast experiment and some analysis of fretting wear scars, we present the idea that two additives react with friction surface step by step. That is to say, the high chemical activity of CuS nanoparticles decompose first and form protective layer, the heat converted from chemical reaction of CuS decomposition and mechanical motion promote composition of common oil additives, thus protective layer is formed once again and wear volume further decrease.
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Multi-operand addition is utilized in various applications like, multiplication, convolution and several image processing algorithms such as filtering. Various adder architectures have been proposed to accomplish the addition of m...
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Multi-operand addition is utilized in various applications like, multiplication, convolution and several image processing algorithms such as filtering. Various adder architectures have been proposed to accomplish the addition of more than two operands, consuming minimum delay and area. Recently, a new technique called flagged prefix addition has been proposed that utilizes prefix tree adders to perform increment and decrement operations by generating flag bits. An extension to this adder has also been proposed enhancing the functionality of the same to allow the addition of any arbitrary number, thereby accomplishing multi-operand addition. This paper extends the idea of generating the flag bits to the carry-skip and the carry-select adders. A thorough evaluation has been performed to analyze the performance of the carry-select, carry-skip, and the prefix tree architectures incorporating the new design in terms of power, area, and delay.
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