Layer Of Soap Research Articles

Experimental study of frictional behaviour of powdered soaps for wire drawing

Better understanding of frictional behaviour of powdered soaps used in dry wire drawing can lead to improvements in wire quality and large savings in energy consumption. The latter is particularly significant given the colossal amounts of energy expended in wire drawing processes. However, there is currently a very limited understanding of the subject, including a lack of quantitative data on soap friction. This is at least in part likely to be due to complex tribological behaviour of the powdered soaps, which is very different from that of lubricating oils. This paper studies frictional behaviour of sodium and calcium powdered soaps, using a ball-on-disc tribometer (ETM rig) incorporating a powder ‘scoop’, and under contact conditions pertinent to die-wire contact in wire drawing. Tests employed a WC ball and C15E steel disc to mimic die and wire materials respectively. Results show that under high sliding conditions, friction coefficient with powered soaps is remarkably low, at 0.03 and 0.04 for sodium and calcium soaps respectively. Friction generally decreased with increasing contact pressure and sliding speed. Post-test analysis of ETM specimens showed the presence of thick soap layers on the rubbed surfaces. However, in ETM tests friction was observed to sharply increase leading to the onset of scuffing, soon after the supply of soap to the contact was interrupted, suggesting that any solid deposited layers are easily removed and cannot exclusively explain the low friction. The observed trends suggest that low soap friction may be due to the ability of the soaps to form low shear stress lubricating films at high contact temperatures which are associated with the harsh conditions of high-speed and high-pressure. The results provide new insights into the frictional behaviour of powdered soaps which can be used to optimise the wire drawing processes as well as a direct input to wire deformation models.

The first record of Pachydiscus launayi De Grossouvre in the Lower Campanian deposits (Upper Cretaceous) of Southwestern Crimea

Lower Campanian Pachydiscus (Pachydiscus) launayi (De Grossouvre) was found for the first time above the layer of soap (bentonite) clays widely known in the literature in an old quarry in the outskirts of the Kudrino village in the southwestern Crimea. This find expands the understanding of the distribution of this species and clarifies the biostratigraphic position of the soap clay layer.

Improved methodology for microplastic extraction from gastrointestinal tracts of fat fish species

Potassium hydroxide (KOH) digestion protocols are currently applied to separate microplastics from biological samples, allowing efficient digestion with minor degradation of polymers in a time- and cost-effective way. For biota samples with high-fat content, KOH reacts with triglycerides generating an overlying soap layer, making difficult the digestion and solubilization and subsequent microplastics extraction. Here we studied the addition of Tween-20 in different concentrations to evaluate the effect on the soap layer of post-digested samples. Addition of 10 % of Tween-20 presented higher flow rate during filtration, being set as optimal value. Incorporation of Tween-20 in the extraction procedure increased recovery rates of LDPE, PC and PET and appears to have a protective effect on PC and PET degradation. Tween-20 did not interfere in FTIR spectrum of polymers available in the marine environment. Being low-toxic, makes addition of Tween-20 a simple and economical way to optimize KOH digestion protocols for microplastics extraction.

Electrochemical coating of zinc carboxylate: A new protection for zinc in atmospheric conditions

To prevent the premature tarnishing of zinc-coated products in moist atmosphere or during wet-dry climatic cycles, new surface treatments of zinc are developed in this study. For that, electrochemical behaviour of pure zinc in this media was studied versus pH and potential by using electrochemical impedance spectroscopy and potentiodynamic techniques. Then, different coatings constituted by zinc heptanoate or zinc hydroxyheptanoate were synthesized by electrochemical oxidation on zinc-coated steel and tested in climatic chamber. The coatings mainly constituted by zinc heptanoate trap the OH − anions and delay the alkalinisation of the zinc surface during the wet-dry cycle. This coating constitutes an environmentally friendly alternative to the usual conversion treatments, to inhibit the formation of hydrozincite (white rust) in atmospheric corrosion. • Zinc soap layer can be formed by electrochemical oxidation of zinc in aqueous medium. • The electrochemical conversion of zinc is more efficient in slightly acid medium. • Crystalline zinc heptanoate constitutes a temporary protection against zinc tarnishing. • Zinc soaps inhibit the formation of powdery white rust on zinc

Zero curvature-surface driven small objects

In this study, we investigate the spontaneous migration of small objects driven by surface tension on a catenoid, formed by a layer of soap constrained by two rings. Although the average curvature of the catenoid is zero at each point, the small objects always migrate to the position near the ring. The force and energy analyses have been performed to uncover the mechanism, and it is found that the small objects distort the local shape of the liquid film, thus making the whole system energetically favorable. These findings provide some inspiration to design microfluidics, aquatic robotics, and miniature boats.

Utilization of a cost effective Lapindo mud catalyst derived from eruption waste for transesterification of waste oils

The most remarkable property of heterogeneous-catalyzed transesterification is its recyclability which surpass the issue by homogenous catalyst. Lapindo mud (LM), an eruption waste from Indonesia, was treated into an active catalyst for transesterification. LM is reasonably tolerant to FFA, as no visible soap layer was observed during transesterification of high acid value WCO (20.723mgKOH/g) and POME (120.48mgKOH/g) with FAME yield of 96.6% and 91.69%, respectively. The reaction conditions obtained for both reaction are mild and comparable to currently reported conditions except LM effectively accelerated the transesterification process of WCO. Reusability test showed that LM exhibited a stable performance with less than 10% declined in FAME after the seventh run with 95% catalyst recovery. Kinetic analysis showed that both WCO and POME transesterification fitted well with Langmuir–Hishelwood first order reaction. The activation energy for WCO and POME transesterification were 55.7 and 59.75kJ/mol. This findings shows the possibility of LM as a catalyst in general heterogeneous reaction and particularly for transesterification to produce FAME.

Characteristics of Fluoride Based Conversion Coating Film on Al-Alloy for Metal Forming Applications

During the process of cold forming of aluminum, the high pressure which is introduced on the die can result in high adhesion between the aluminum and the die surface. Therefore, it is necessary for the aluminum billet to be coated with a lubricant prior to forming, to reduce adhesion and to ease the flow of material in the die. There are several popular types of lubricant systems used in cold forging of aluminum. For severe deformation, conversion coating in conjunction with soap lubricant are commonly used. The conversion coatings include soap phosphates (PO4-soap), as well as soap aluminum fluoride (AlF-soap). Therefore, this work studied the performance of the AlF-soap system and compared it to the conventional PO4-soap system as tested on AA6063 aluminum. Ring compression tests and ball on disc tests were conducted to explore friction conditions and the thinning of the lubricant under several forming conditions. It was found that the quantity of metal soap layer of AlF-soap used affected the friction coefficient and the lubricant thinning under forming operation. The suitable coating weight of metal soap layer of AlF-soap for this experiment was found to be 2 g/m2. The friction coefficient of the PO4-soap system was 16.26% lower than the AlF-soap system. However, the amount of thinning of the AlF-soap film after ring compression tests was lower than that of PO4-soap film.

Fabrication of free standing, three-dimensional, fibrous, thin film substrates of parylene C

Microscale ultraviolet lithography to pattern a silicon wafer, spin coating of a layer of soap solution and physicochemical vapour deposition of two thin films of parylene C were sequentially used in a seven-step procedure to fabricate free standing, three-dimensional, fibrous, thin film substrates of parylene C for biomedical application. The effects of the length scales of the photoresist pattern on the wafer, the flowrate of the reactive monomer flux of parylene C and redistributive diffusion of the monomer molecules on the top surfaces of the thin film substrates were established. The top surface morphology of a thin film substrate is controlled by the photoresist pattern and the volumetric morphology of a fibrous thin film. The bottom surface of the thin film substrate acquires a multiscale morphology both from the photoresist pattern and from the baking of the soap layer.

Surface‐Enhanced Raman Spectroscopy of Tribochemically Formed Boundary Films of Refined and Unrefined Canola Oils

AbstractThe paper reports the investigation of tribochemically formed boundary films of canola oils using surface‐enhanced Raman spectroscopy. This is the first time that metallic surfaces lubricated by plant oils have been studied using this technique. The results of this work provided strong evidence that fatty acids were liberated from the triglyceride structure during sliding to form a fatty acid soap layer on the silver surface. The study also revealed that the fatty acid chains of the unrefined canola oil were more disordered and most likely in a gauche conformation, while that of the refined canola oil were tightly packed and oriented perpendicular to the surface. It is believed that the greater presence of polar minor components in the unrefined oil, such as phospholipids, interfered with the ability of free fatty acids to form a tightly packed monolayer on the silver surface.

Suitability of Using SOAP Protocol to Secure Electronic Medical Record Databases Transmission

Simple object access protocol or SOAP originally defined as protocol specification for exchanging structured information. SOAP relies on XML for its message format and other application protocols, particularly RPC and HTTP. XML considered as the universal language for data transmission on the Internet, however, end-to-end protection of messages must either be implemented within applications or it can be provided by middleware above the SOAP layer, therefore, SOAP-XML can not provide the level of confidentiality for transferring electronic medical databases. In this paper, we will investigate SOAP protocol structure over XML, the purpose of this paper is identify the possible way towards implementing secure protocol to transfer electronic medical records databases or creating electronic medical records backups over unsecure channels. As a conclusion, SOAP alone can not provide the level of security that medical records databases deserve.

Some tribological and environmental aspects in metal drawing

The methods of soap powder lubrication in dry drawing of metals are compared with a novel solid film lubrication. Concerning powder lubrication the required lubricant carrier or conversion treatments of the forming material surface are also considered. Both the tribological as well as the environmental aspects indicate the high potential of solid film lubrication. By means of examples the problem of aqueous dispersion stability of calcium soap systems is dealt with, which is one of the main problems in developing suitable coating systems. After coating, the adhesive and rheological behaviour of the dried solid soap layers on the wire or rod surface enable an excellent hydrodynamic pressure to be built up during the drawing process. When using a double die pressure tool, the pressure development is substantially controlled by the inlet die. In applying the solid soap film lubrication some environmental advantages with respect to soap powder lubrication become obvious. Chemically aggressive substances, such as lubricant carriers and conversion chemicals or acid pickling solutions, can be minimized or even eliminated. Moreover, rinsing water pollution and lubricant dust are reduced.

Modified method for the determination of unsaponifiable matter in oils and fats

Download options Please wait... Article information DOI https://doi.org/10.1039/AN9941901793 Article type Paper Download Citation Analyst, 1994,119, 1793-1795 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions Modified method for the determination of unsaponifiable matter in oils and fats L. Hartman, H. S. Viana and S. Freitas, Analyst, 1994, 119, 1793 DOI: 10.1039/AN9941901793 To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Social activity Tweet Share Search articles by author Leopold Hartman Hudson Soares Viana Suely Freitas

Comparison of methods of repelling mosquitoes

AbstractComparisons were made with human subjects of repellency of free flying Anopheles gambiae using soaps containing deet and permethrin or permethrin alone. The reduction in biting did not differ statistically significantly between these two forms of repellent soap. Some mosquitoes which touched the permethrin soap layer without biting died within the next day. The soap with deet was compared with the same amount of deet in a commercially available stick or as a liquid. Only in the latter form did the repellent show resistance to being washed off by cold water.Electrically heated vaporizing mats containing bio‐allethrin were shown to be more effective than smouldering coils containing natural pyrethrins, in that there was more complete prevention of biting, and more rapid knock‐down and kill. Operation of the vaporizing mat caused deposition of insecticide on the room surfaces.

Langmuir–Blodgett films of long-chain amines

Widespread interest has developed in the potentialities of molecular films built up on solids by the Langmuir–Blodgett (L–B) technique of sequential transfer of monomolecular layers from a water surface1,2. For certain purposes, the fatty acid soaps which are the classical, and most extensively studied, constituents of L–B films, may be unusable. For example, it may be desired to incorporate acid-sensitive molecules, or the presence of heavy-metal ions such as barium or cadmium, which are required to produce the most stable soap layers, may be undesirable. These problems may be overcome in some instances by the use of fatty alcohols or esters, but multilayers of these substances are generally less stable (especially with respect to thermal disruption or vaporization) than those of the heavy-metal soaps. I now report methods for the facile formation of L–B layers of long-chain amine salts which offer comparable, as well as complementary, advantages compared with soap films.

Dynamics of freely suspended lyotropic films. I. An inelastic light scattering study of thermal surface fluctuations

We have studied the spectrum and intensity of light scattered by thermal surface displacement fluctuations on freely suspended lyotropic films. Films consisted of a liquid core and surface soap layers and were drawn from solution containing water, glycerol, NaCl, and the ionic surfactant hexadecyltrimethyl ammonium bromide (HTAB). Two modes were observed: a propagating undulation mode in which the film surfaces move together and a damped peristaltic mode having oppositely moving surface soap layers. Dispersion relations for these modes, obtained from the dependence of the scattered light intensity correlation function on film thickness h and wave vector k, confirm the macroscopic hydrodynamic description of film motion. In particular, the overdamped peristaltic mode is shown to involve Poiseuille flow of the fluid core with the flow velocity zero within 2 Å of the surfactant–solution interface, indicating no significant slip or rigid interfacial water layer. No evidence of dispersion in the effective viscosity of the fluid core h(k,w) over the range 0<k<106 cm−1, 0<w<103 sec−1 was found. The undulation mode was found to be underdamped, with frequency in the range of 400 kHz to 1 MHz, the largest observed to date for surface waves in fluids. The dynamic surface tension term s(k,w) for k∼106 cm−1 and w∼6×10 sec−1 was found to be the same as the static value within experimental error. Analysis of the total scattered intensity and of the peristaltic mode dynamics allows the determination of R(h), that part of the film pressure due to electrostatic repulsive and van der Waals attractive forces. The measured R(h) are well represented by the sum of a repulsive screened electrostatic interaction and an attractive van der Waals term. The screened electrostatic interaction is consistent with the concentration of NaCl used and the attractive part of R could be fitted equally well by the simple nonretarded van der Waals form for a uniform dielectric slab, or the Ninham–Parsegian form for a three layer hydrocarbon–water–hydrocarbon slab.

Polymorphism of Alkyl Sulphate Soaps

ALKYL sulphate soaps NaSO4CnH2n + 1, like the fatty acids and alcohols, may be expected to have a tendency to join together the hydrophylic groups of neighbouring molecules. In the crystalline state, this tendency will lead to sheets of double molecules with stretched chains more or less perpendicular to the sheets. We have measured the corresponding long spacing, using the classical method of copper Kα reflexion, at a thin layer of soap on a glass slide, the distance plate to axis in the Muller camera being 10 cm. During the investigation, we saw a paper by Rawlings and Lingafelter1, who made a complete determination of the unit cells. They found different modifications, the α-form with the smallest water content being the most stable. We have also found this α-modification. Moreover, we succeeded in making all our substances crystallize completely in this modification. This proves the chemical homogeneity (within some per cent) of our substances and their identity with Rawlings and Lingafelter's substances. As we have, however, also found a number of rather stable modifications not mentioned by them, we give here a short account of our procedure.

The area of real contact and the shear strength of monomolecular layers of a boundary lubricant

A method has been developed by which molecularly smooth surfaces may be placed together and the area of contact formed between them measured. Selected sheets of mica were cleaved to be free from cleavage steps on both sides of the sheets. These were bowed up and mounted as crossed cylinders in an apparatus in which normal and tangential loads could be applied. The area of contact formed between the surfaces has been examined using multiple-beam interference techniques. Examination of the hue and intensity of the central region of the interferograms enables a separation of the mica sheets to be detected even if this is of only a few ångströms. This means that the boundary of the region of contact may be determined with a greater precision than has hitherto been possible. Fringes of equal chromatic order provide a sensitive means for the detection of small particles of accidental contamination and have been used to show when the contact is intimate over the whole region. Normal and tangential forces have been applied to the mica specimens, both when in a clean condition and when covered with a monomolecular layer of calcium stearate. The area of contact was observed simultaneously. The area and the force required to shear it being known, the shear strength of the junctions has been calculated. The damage occurring during the process has been examined using reflexion electron microscopy. At certain values of the tangential force smooth sliding takes place on the lubricated surfaces and no surface damage can be detected. Further increase of the tangential force produces a rapid slip causing fragments to be torn out of the surface and some damage occurs. No smooth sliding was detected on unlubricated surfaces of mica and the damage produced during the slip was extensive. The force required to shear the junction formed between clean smooth mica surfaces is very high. A value of 10 Kg/mm2has been obtained. For the monomolecular layers of calcium stearate the value obtained is about forty times lower but is by no means negligible. This means that a considerable force is required to shear a film of boundary lubricant and accounts for the otherwise unexplained observation that when metals are lubricated with a single molecular layer of soap or fatty acid the frictional force is reduced by only a factor of 10 while the wear decreases by a factor of 10000 or more.

A radioactive tracer study of the behaviour of long chain organic molecules on solid surfaces

The adsorption and possible mechanisms for the surface transport of stearic acid and some of its derivatives on solids have been investigated using radioactive tracers.� mono- and multimolecular layers of these compounds were deposited on quartz glass, mica, and metal specimens, which were then held at various temperatures for a short period. The resulting changes in amount and distribution of activity were determined by autoradiography or an appropriately designed Geiger tube. On unreactive surfaces such as platinum or quartz glass the pure acid is only weakly adsorbed and thermal desorption, in general, readily occurs, especially of layers deposited on an initial monolayer. Layers of copper or calcium soaps on all surfaces, either deposited as such or formed in situ, are very much more stable. There is also some evidence that desorption is favoured by the presence of water vapour. Both pure acid and soap layers have some resistance to mechanical abrasion, but none to dissolution by hot benzene unless the adsorption involves a chemical bond. Part B of the present paper describes an experimental search for a long-range surface diffusion, using the same surfaces and adsorbates. It is shown that, under favourable conditions, material desorbed from one part of a surface will readsorb elsewhere after movement over considerable distances in the vapour phase. This mechanism may account for some examples of apparent surface diffusion reported by earlier workers. If, however, this vapour phase transport is suppressed, then no evidence can be detected of a true surface diffusion over macroscopic distances.

Studies on rate of emulsion polymerization of butadiene‐styrene (75:25) as a function of amount and kind of emulsifier used with persulfate as activator. IV. Addition of emulsifier during reaction. Seeding effects

AbstractThe effects of some factors on the rate of emulsion polymerization of butadiene‐styrene (75:25) in the GR‐S recipe at 50°C. are reported. The effects studied are the addition of soap during polymerization and the use of partially polymerized latex as seeder for the polymerization of the other ingredients of the recipe without further addition of soap.The addition of soap during the polymerization causes an acceleration of polymerization even if the amount added is less than that required for the formation of a monomolecular layer of soap on the surface of the polymer particles. This acceleration occurs even at conversions at which all the unreacted monomers are dissolved in the polymer particles.The seeding effect is accounted for on the assumption that after the disappearance of soap micelles, the particles are the only loci of reaction. The magnitude of the seeding effect is determined mainly by the amount of polymer that is added, the size of the polymer particles in the seeder being of secondary significance in determining the rate of polymerization.

Gels and jellies of aluminum dilaurate in cyclohexane and benzene examined by x-ray diffraction

Aluminum dilaurate, AlOH · L 2, swells to a gel in cyclohexane without greatly disturbing the crystalline diffraction pattern of the soap. After heating and cooling the system, the lines of the pattern for the gel are less distinct but the spacings are the same as before. However, a jelly formed by heating a system of 40% aluminum dilaurate in benzene to 150°C. gives a pattern at room temperature that indicates the disappearance of the original crystallites of soap and the probable formation of micelles of oriented soap layers.