182,244 research outputs found
Wax removal using pipeline pigs
No full textThe deposition of paraffin wax solids in pipelines and risers represents a continuing challenge to flow assurance in offshore installations. Wax deposits reduce product throughput, requiring increased energy expenditure to re-establish flow levels. In severe cases, wax deposits can completely block a pipeline. Preventative solutions to the problem such as pipeline insulation, active heating of pipes or chemical dosing with wax inhibitors are not always economically viable, so mechanical removal using a device known as a 'pig' remains an economical solution to the problem of wax removal. A pig is a cylindrical tool that is driven through the pipe by the flow of product, scraping deposits from the pipe wall as it travels. Despite the importance of pipeline pigging to the oil and gas industry, the effectiveness of pigs in removing wax is poorly understood and it is this problem that is addressed by this thesis. One of the first necessities in undertaking this work has been to define the mechanical properties of wax deposits. This has required critical analysis of published material on the subject of wax deposition along with practical experimentation to create representative models of wax deposits that require mechanical removal from pipelines. Previously, studies of wax removal using pigs have assumed the mechanics of the process to be adequately represented by uniaxial compression or simple shear load models. In this work wax removal is analysed using the orthogonal cutting model. This provides a more accurate description of the process as it includes the effect of material after yielding (the chip) on the net wax removal force. Experiments were designed to allow testing of the validity of the orthogonal cutting theory to the pigging process under a variety of conditions. An original contribution from this work is through experimental and theoretical results that are given context through comparison with established metal cutting theory. Through experimentation a specific cutting energy is obtained for wax removal. The results of the wax cutting experiments have identified particular differences between wax cutting and metal cutting regarding the homogeneity of chip formation. These observations have important implications in predicting wax removal forces using mechanical removal tools. Although the affect of removed wax chips on pigging forces has been neglected in theory, it is well known in practice. The fluid used to drive cleaning pigs is often used to produce a jet radiating centrally from the front of the pig intended to blast wax chips away from the pig body, avoiding formation of a 'plug' of wax ahead of the pig. In this study a novel variation of this process in the form of an annular bypass jet is experimentally studied. A semi-empirical model of wax removal using an annular bypass jet has been developed and empirical constants obtained to allow prediction of removal rates for different waxes under various conditions. The new model introduced here allows balancing of pig velocity with wax removal velocity so that a non-contacting wax removal system is obtainable. The bypass-jetting model has been validated using a full-scale trial of the process by industrial sponsors
The safety and effectiveness of different methods of ear wax removal: a systematic review and economic evaluation
No full textEar wax (cerumen) is a natural secretion produced to protect the inner ear from dirt and other fragments by moving these particles towards the outer ear. If this process does not happen properly, wax may build up causing blockage in the ear canal and the possibility of impaction. People with a build up of ear wax may suffer from hearing loss, discomfort and, on occasions, infection. It may present problems in assessing hearing, blocking the view of the ear drum during medical examination and interfering with the fitting or function of hearing aids. Although it is thought to affect between 2% and 6% of the population in the England and Wales, some groups may be at a higher risk, such as those using hearing aids or with small ear canals and/or skin conditions. Recurrence is thought to be high among some of these groups. The consequences of the build up of ear wax in the ear canal are thought to be a common reason for consultation and cost in general practice with over 2 million consultations per year in the NHS.Methods of removal of ear wax include drops, flushing with water in general practice, and removal with suction or probes in specialist clinics. The relative safety and benefits of these different methods of removal remains uncertain. This research will systematically review published and unpublished evidence on the clinical and cost effectiveness of different methods for the removal of ear wax. Where appropriate, it will develop an economic model using data from this systematic review and other relevant sources to estimate the relative costs and benefits of different methods. In addition, the project will provide recommendations for future research to try to help answer any remaining areas of uncertainty
The composition of wax and oil in green coffee beans
No full textMethods for the isolation of wax and oil from green coffee beans were studied and a method for the quantitative extraction of coffee oil from the beans was introduced. Coffee wax, coffee oil and wax-free coffee oil as well as the unsaponifiable matter prepared from each were fractionated by column chromatography. The chemical composition of the fractions was studied by thin-layer chromatography, gas-liquid chromatography, ultraviolet, infrared, nuclear magnetic resonance and mass spectrometry. The results include qualitative and quantitative data on (1) the total fatty acid composition as well as the composition of the fatty acids in triglycerides and diterpene alcohol esters, (2) the positional distribution of the fatty acids in the triglycerides, (3) the unsaponifiable matter and (4) Nβ -alkanoyl-5-hydroxy-tryptamines (C-5-HT) and other C-5-HT-like phenolic compounds.The unsaponifiable matter (3) was fractionated into diterpene alcohols, sterols and hydrocarbons (including squalene and n -alkanes from C 16 to C 31 ). Moreover the presence of α-tocopherol and (β+ γ)-tocopherol in green coffee beans was described for the first time.In view of the results of this study the removal of coffee wax by industrial processes, which are claimed to have a beneficial effect on the digestibility of coffee, was discussed. The current literature on the lipids of green coffee beans was extensively reviewed
Optimisation of the Wax and Oil Phases in a Conventional Lipstick Using Mixture Design
No full textLipstick is essentially a mixture of oils, waxes and pastes. The type and ratio of ingredients in the lipstick base determine the type and intensity of interactions, which directly affect the quality of lipstick. Fundamentally, a lipstick must have sufficient stick strength to withstand the force during application, but it should also have appropriate ‘pay off’ characteristics. The traditional empirical approach may be inefficient in the development of lipsticks, because of the number of formulation variables and the two competing requirements.
The results of this study have revealed the quantitative relationship between the hardness of a lipstick (expressed as its breaking and softening point) and its ‘glide’ performance. The use of the Mixture Design approach has made it possible to effectively select the samples with the best overall characteristics, on the basis of limited but focused experimental work
Plant wax biomarkers in human evolutionary studies
No full textAbstract Plant wax biomarkers are an innovative proxy for reconstructing vegetation composition and structure, rainfall intensity, temperature, and other climatic and environmental dynamics. Traditionally used in earth sciences and climate studies from ?off-site? ocean and lake records, biomarker research is now incorporated in archeology and paleoanthropology to answer questions relating to past human-environment interactions and human evolution. Biomarker research is generating new and exciting information on the ecological context in which Homo and its closest relatives evolved, adapted, and invented stone tool technologies. In this review, we examine plant wax biomarkers and their use in reconstructing past plant landscapes and hydroclimates. We summarize the applications of plant wax molecular proxies in archeological research, assess challenges relating to taphonomy, consider the role of modern plant ecosystems in interpreting ancient habitats, and examine case studies conducted at key paleoanthropological locations in eastern and southern Africa and Europe.1 Introduction 2 Complementary addition to multi-proxy studies 3 Taphonomic normalization 4 Establishing the plant wax ecology of modern african soil 5 Plant waxes shed light on multiple aspects of human evolution 5.1 Orbital forcing and hominin ecology 5.2 Plant landscape variability 5.3 Hominin targeted ecotones 5.4 Activity areas in caves and rock shelters 6 Where do we go from here
Wax.
No full textPatent for improving wax to be used by shoemakers consisting of gasolene [sic], rosin and pine tar. The improved wax adheres to the shoe leather and the threads making both the leather and the seams waterproof and more supple. This wax product does not blacken the hands of the shoemaker
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Insecticidal potential of wax-degrading bacteria derived from fermented Ficus extract against Phenacoccus solenopsis Tinsley
No full textAims: Phenacoccus solenopsis is a pest of many agricultural and horticultural crops, causing considerable losses in Asia and other parts of the world. Managing P. solenopsis is challenging due to a waxy covering body and high reproductive potentiality. This study was aimed to explore the potential use of wax-degrading bacteria isolated from fermented Ficus extract against P. solenopsis. Methodology and results: A total of ten isolates of wax-degrading bacteria were isolated from fermented Ficus extract (Ficus FPE) using a selective medium, Davis minimal agar (DMA), which was enriched with mealybug wax. The wax-degrading ability of the bacteria was evaluated through a turbidimetry test using 2, 6-dichlorophenol indophenol (DCPIP). Bacillus sp. 42PB3 demonstrated the highest wax-degrading potential, with 64.78% mealybug wax degraded and 73.85% paraffin wax degraded. The bioassay was conducted with three bacterial concentrations (108, 107 and 106 ) tested against third-instar nymphs of P. solenopsis on Hibiscus rosa-sinensis by top application technique in completely randomized design (CRD) design with ten replications. The cell suspension and supernatant of Klebsiella pneumonia, Paenibacillus sp. 21F1E3, Bacillus sp. 35F1C1 and Bacillus sp. 42F1B3 isolates caused 70-83% and 60-66% mortality (supernatant) after 168 h post-treatment. Klebsiella pneumonia badly affected the offspring production of the treated mealybug with the lowest number of crawlers (80.2), followed by Paenibacillus sp. 21F1E3 isolate (111). Conclusion, significance and impact of study: In the present study, all tested bacteria isolated from fermented Ficus extract showed varying levels of wax-degrading ability and insecticidal activity against P. solenopsis. These bacterial isolates show promise as an environmentally friendly biocidal agent for managing P. solenopsis, potentially curbing crop losses and ensuring food quality through sustainable pest management practices in the future
Wax crystallization and aggregation in a model crude oil
No full textThe high-molecular-weight paraffinic (‘wax’) fraction separates from crude oils at low temperatures, a process that can lead to a sol–gel transition when the mass of wax solids exceeds 1–2%. Attractive interactions between the micron-size wax solids suspended in the non-polar medium have been suggested to be responsible for gel formation. The present study reports an optically transparent model oil system, based on a mixture of linear and branched paraffins. Rheology and optical microscopy show that the model system reproduces essential features of crude oil gels. Small-angle light scattering studies show that phase separation and wax solid aggregation are rapid processes, leading to the formation of dynamically arrested structures well above the sol–gel transition determined rheologically. Clusters formed by the aggregated wax solids possess a fractal dimension of about 1.8, consistent with diffusion-limited cluster–cluster aggregation
A R C H I V E S O f F O U N D R Y E N G I N E E R I N G Evaluation of wax pattern properties in the lost-wax process
No full textAbstract This article present achieved results of examination of wax pattern properties (wax compounds) which are used in lost wax process. Evaluation of those results was made with approach as it is taken in foundry. Evaluation included: evaluation of wax compound shrinkage, bending strength test, hardness test using penetration method, and resistance to creep of wax patterns in precision foundry environment
- …
