Stripping

Asphalt is sticky, black and viscous liquid substance which extensively known as bitumen and broadly useful in the construction of roads and bridge pavements. Its natural adhesive characteristics makes it possible to combine all required aggregate together to produce a greater amount of strength to sustain the higher traffic loads. Asphalt is naturally originated substance and it also could distinguish from the petroleum by products. A major application of asphalt material is to make high strength road pavements and as an adhesive to combine aggregates together for several applications. Deterioration or elimination of asphalt binder from aggregate layer due to the effect of moisture is generally named as the " stripping ". Moisture damage or stripping distress is one of the most severe causes of damage in asphalt pavement. This paper will exhibit the stripping distress due to the water (moisture) effect on the bitumen pavements and how that damages could be cured. Asphalt roads may face destructions due to water or moisture vapor. These hazards may damage roads in such critical ways which results in temporary close-up or permanent renewal of that particular pavement. This paper will discuss remedies and maintenance techniques should be taken while the stripping characteristics affect the asphalt pavements and it will also cover the basic critical points should be taken in the consideration while constructing the asphalt pavement to reduce the stripping hazard effects on it. Recommendations are also made in the research to minimize the occurrence of such premature failure resulting from stripping distress.

Economic analyses of absorption system components have been conducted with the aim to optimize the various operating parameters. The absorber, condenser, evaporator, generator, rectifier, precooler and preheater have been designed using standard procedures, and their costs have been estimated based upon the materials used, fabrication installation and overhead charges. Four types of refrigerant-absorbent combinations (H2O-LiBr, NH3-H2O, NH3-NaSCN and NH3-LiNO3) using

The effect of bis-2-ethylhexylphosphoric acid (D2EHPA), bis (2,4,4-trimethylpentyl) phosphinic acid (Cyanex 272), and tri-butyl phosphate (TBP) and their mixtures in various proportions for the separation and extraction of zinc and manganese from sulfate solutions were investigated. Experiments were carried out in the pH range of 0.5-5.0 at 25, 40, and 60_C. It was shown that the extraction of zinc and manganese by D2EHPA and/or Cyanex 272 can be increased by the increase in pH and temperature. The synergistic extraction and separation of zinc and manganese with a mixture of D2EHPA and Cyanex 272 was studied and the results showed that mixing the two extractants improved the extraction capacity of the mixture. Increasing the D2EHPA to Cyanex 272 ratio in the organic phase, caused a right shifting of extraction isotherms of manganese and zinc; shifting the manganese curve was more than zinc. The manganese curve had considerable right shifting with 5% D2EHPA and 15% Cyanex 272. TBP did not affect the zinc (Zn) and manganese (Mn) extraction. The stoichiometric coefficients of Zn and Mn were determined ith 20% and 5% D2EHPA and 15% Cyanex 272 by applying the slope analysis method. The organic phase was stripped by sulfuric acid. © Taylor & Francis Group, LLC.

Increasing regulations and constraints have renewed interest for more efficient distillation process in separating azeotropic mixtures and close boiling components. We investigate the feasibility of heterogeneous extractive distillation process in a continuous column considering several feed point strategies for the entrainer recycle stream and for the main azeotropic feed. Depending on these choices, the heterogeneous distillation column is composed of one, two, or three column sections. A differential mass balance model enables to compute continuous liquid composition profiles of the rectifying, extractive, and stripping sections. Unlike homogeneous extractive distillation, reflux policy composed by a single or both decanted liquid phases is considered as well as the external feeding influence on the composition of the top column liquid stream. Limiting operating conditions of key parameters like the entrainer/feed flowrate ratio and reflux ratio required to obtain a target top and bottom product compositions are obtained. For illustration, separation of acetonitrile–water mixture using butyl acetate as a heavy heterogeneous entrainer is selected. In this case, withdrawal of a saddle binary heteroazeotrope is the main difference of this process compared with the well-known heterogeneous azeotropic distillation process where the top vapor product is the lower boiling point of the ternary system. © 2007 American Institute of Chemical Engineers AIChE J, 2007

Presence of water in porous asphalt mixtures detrimentally affected the bonding between binder-aggregate interface and cohesive failure within the binder-filler mastic, making them prone to stripping which contribute to the performance and durability. This paper presents the effect of anti-stripping additives in porous asphalt mixes. In this study, the Marshall specimens were prepared using quarry dust, ordinary Portland Cement (OPC) and Pavement Modifier (PMD) as filler then mixed with 60/70 penetration grade bitumen. The specimens were measured for air voids content and coefficient of permeability and subsequently tested using indirect tensile and Cantabro tests. The moisture sensitivity of porous asphalt was determined based on the ratio of dry and conditioned specimens according to AASHTO T283. The specimens prepared with PMD showed lower air voids content, hence decrease the permeability to give a higher tensile strength and lower abrasion loss compared to specimens prepared wi...

BACKGROUND: A series of nine conventional and non-conventional flow-sheets have been considered for the recovery of uranium from acidic sulfate solution by liquid–liquid extraction with 0.146 mol L−1 Alamine® 336 in kerosene modified with 5% w/w 1-tridecanol and stripping with a 199 g L−1 Na2CO3 solution. The reference flow-sheet was a classical counter-current configuration with four mixers–settlers in the extraction stage and three mixers–settlers in the stripping stage. The others flow-sheets possessing a total of eight mixers–settlers are unusual combined solvent extraction flow-sheets with one or two independent extraction stripping loops and with one or two feed inlets.RESULTS: The configuration of the flow-sheets strongly influences the extraction performance of the process depending on the working conditions (feed, stripping and solvent flow rates). The presence of two independent extraction–stripping loops may allow the delay of the saturation phenomenon encountered in the conventional flow-sheet and thus, to operate at higher feed flow rates without loss of performance, as far as the residual fraction in the raffinate and the concentration factor in the stripping solution are concerned. Furthermore, the presence of a modification in the non-conventional flow-sheets with two independent extraction–stripping loops and two feed inlets leads to interesting configurations for uranium recovery from less concentrated solutions, such as heap leach solutions.CONCLUSION: The use of non-conventional flow-sheets is interesting as it allows the process of uranium (VI) recovery by liquid–liquid extraction to be improved. Copyright © 2009 Society of Chemical Industry

Increasing regulations and constraints have renewed interest for more efficient distillation process in separating azeotropic mixtures and close boiling components. We investigate the feasibility of heterogeneous extractive distillation process in a continuous column considering several feed point strategies for the entrainer recycle stream and for the main azeotropic feed. Depending on these choices, the heterogeneous distillation column is composed of one, two, or three column sections. A differential mass balance model enables to compute continuous liquid composition profiles of the rectifying, extractive, and stripping sections. Unlike homogeneous extractive distillation, reflux policy composed by a single or both decanted liquid phases is considered as well as the external feeding influence on the composition of the top column liquid stream. Limiting operating conditions of key parameters like the entrainer/feed flowrate ratio and reflux ratio required to obtain a target top and bottom product compositions are obtained. For illustration, separation of acetonitrile–water mixture using butyl acetate as a heavy heterogeneous entrainer is selected. In this case, withdrawal of a saddle binary heteroazeotrope is the main difference of this process compared with the well-known heterogeneous azeotropic distillation process where the top vapor product is the lower boiling point of the ternary system. © 2007 American Institute of Chemical Engineers AIChE J, 2007

The first goal of this article is to argue that phrasal temporal adverbial constructions like Al left before Pat are derived via ellipsis from an underlying clausal source. The second goal is to demonstrate and account for the restricted distribution and interpretation of these reduced phrasal temporal adverbial constructions relative to their clausal counterparts and to temporal adverbial constructions targeted by VP ellipsis. The proposed analysis provides evidence for an operator-variable parallelism condition on ellipsis and supports models for an identity condition on ellipsis that allow the identification of an antecedent within the phrase-structure representation of the utterance.

Stone matrix asphalt (SMA) is a hot mixture asphalt consisting of a coarse aggregate skeleton and a high binder content mortar. It was developed in Germany during the mid-1960s and it has been used in Europe for more than 20 years to provide better rutting resistance and to resist studded tyre wear. The main objective of this research study was to compare the performance of the normally used dense graded asphalt mixtures, named in this research as control mixtures, and SMA mixtures. Samples from both mixtures were fabricated at their optimum asphalt contents that were 5.3% for control mixtures and 6.9% for SMA mixtures. Comparison performance tests that included Marshall stability, loss of Marshall stability, split tensile strength, loss of split tensile strength, resilient modulus, fatigue, and rutting testing were performed on both mixtures. Test results showed that although the control mixtures have higher compressive and tensile strengths, SMA mixtures have higher durability and resilience properties. In addition, although the research could not prove the superiority of SMA in rutting resistance because of the limited sample sizes, field performance of SMA mixtures proves its superiority. Therefore, especially in hot weather climates, these properties, (durability, resilience and rutting resistance) give SMA mixtures advantages over dense graded mixtures.

Exotic dance is often falsely associated with illegal forms of sexual labour, as well as with "deviance"; thus promoting the view that exotic dancing is somehow pathological. These views undermine the dancers' ability to be seen as individuals with their own stories and experiences. Participants in this study were interviewed with the focus on experiences in the exotic dance industry, family histories, relationships, and personal networks. narratives were analyzed by means of thematic network analysis. Common stereotypes were debunked, and some dancers clearly experience meaning, healing, gratification and power in their work, and they live responsible, productive lives.

The first goal of this manuscript is to argue that phrasal Temporal Adverbial Constructions (TACs) like 'Al left before Pat' are derived via ellipsis from an underlying clausal source. The second goal is to demonstrate and account for the restricted distribution and interpretation of these reduced phrasal TACs relative to their clausal counterparts and TACs targeted by VP-Ellipsis. The proposed analysis provides evidence for a Parallelism condition on ellipsis and supports models for an identity condition on ellipsis that allow the identification of an antecedent within the phrase structure representation of the utterance.

Stripping is an important type of distress about which gaining thorough information can improve the pavements design methods. A brief review of researches on the stripping potential of asphalt mixtures over the past 40 years has been presented in this paper. The contents of the article include mechanisms of moisture damage occurrence and contributing factors, as well as an introduction to the variety of steps taken in an effort to experimentally and numerically model the moisture damage propagation. Researches on stripping have been divided into three categories of field studies, laboratory investigations, and numerical and computational analysis. Laboratory experiments are also categorized into five groups. Tests on loose mixtures, destructive mechanical tests on asphalt concrete, nondestructive mechanical tests on asphalt concrete, mechanical tests which provide a measure of cohesion in asphalt and adhesion between asphalt and aggregate, non-mechanical tests which provide a measur...

An emulsion liquid membrane process using tri-n-octylamine (Alamine 300) to extract and separate cobalt from the acidic leach solutions has been presented. Liquid membrane consists of a diluent, a surfactant (ECA 4360J), and an extractant (Alamine 300, Cognis Corp.). Ammonia solutions have been used as the stripping solution. The important parameters governing the permeation of cobalt and their effect on