Enhancement of Flotation Performance of Oxidized Coal by the Mixture of Laurylamine Dipropylene Diamine and Kerosene

Conventional hydrocarbon oil cannot adhere effectively to oxidized coal, resulting in a low yield of clean coal. In this study, a high-speed homogenizer was used to emulsify LDD (laurylamine dipropylene diamine) and kerosene, which enhanced the flotation efficiency of oxidized coal. The flotation results showed an increase from 4.12% (only kerosene) to 23.33% (emulsified oil). An increase in contact angle indicated that the mixture reagent can increase the hydrophobicity of coal particles, which is attributed to the adsorption of LDD onto the coal particle surface and the decrease of the oil droplet A lower surface tension of LDD allows it to produce a stable layer of froth than the layer generated by kerosene alone.

Investigation about wetting ability (surface tension) of water used for preparation of pesticide solutions

<p class="042abstractstekst">The investigation about surface tension of water used for preparation of pesticide solutions reveals it is quite diverse and changeable without any logical correlation towards location, time, and type of water source. Moreover, spraying with solutions with lower surface tension give bigger flow rates due to the lower resistance of fluid to the nozzles. The conducted trials show that plant surfaces with more rough texture require to be sprayed with pesticide solutions with lower surface tension. The wax content of the surfaces has no significant impact on surface tension requirement.</p><p> </p>

The Garbage Enzyme with Chinese Hoenylocust Fruits Showed Better Properties and Application than When Using the Garbage Enzyme Alone

Garbage enzyme (GE) is a vinegar or alcohol product derived from fermenting fresh kitchen waste, such as vegetable and fruit residues (peels, cuttings and bits), sugar (brown sugar, jaggery or molasses sugar) and water. Chinese honeylocust fruits (Gleditsia sinensis) have been used in China for at least 2000 years as a detergent. The aim of the study was to investigate the properties and application of Chinese honeylocust garbage enzyme (CHGE), which is produced when equal amounts of Chinese honeylocust fruits and fresh wastes are mixed. The results showed that CHGE had lesser microbial communities and lower surface tension than GE. CHGE also had higher viscosity, foam stability and emulsion stability than GE. Compared with GE, CHGE induced higher enzymatic amylase, cellulase, lipase and protease activities. CHGE had stronger detergency than GE and a 100× dilution of CHGE could significantly remove pesticide residues after a 30 min soaking treatment. The study showed that as a biological detergent, CHGE is safer and more environmentally friendly than GE and has remarkable washing and cleaning power. The preparation method of the detergent is simple: it can be prepared at home using fruit and vegetable waste, which is beneficial to the secondary utilization of waste and the reduction of pollution to the environment and damage to human health.

Pengaruh Kemiringan Saluran Terhadap Fenomena Flooding Dengan Gangguan Pada Aliran Udara–Air Dan Udara–Minyak Tanah

Some equipments which are used in petroleum industries, chemical industries, steam power-plants and nuclear reactors must avoid the flooding phenomena in order to work at optimal condition. The purpose of this research is to investigate the effects of inclination and obstacle on flooding onset at counter-current air-water and air-kerosene flows with porous inlet and sharp outlet. The model of obstacle was conformed to industrial application i.e .pipe joining or pipe scaling. Experimen ts were conducted in a plexyglass pipe of 25.4 mm diameter and 2500 mm length of test section at annular flow pattern. The variation of inclination of ducts are 90o, 80o and 60o. The geometry of the obstacle is a ring with rectangular cross sectional which is installed with a distance 600 mm or 1200 mm from the inlet. The result of the research indicated that the effects of inclination and obstacle of ducts are significant toward flooding onset. Flooding phenomena was indicated with drastic increase of pressure gradient above the liquid inlet. Flooding phenomena happened earlier of larger inclination of the ducts and nearer obstacle of the inlet. This phenomena also early happened at kerosene which have higher viscosity and lower surface tension than water

Numerical Analysis of Effects of Surface Tension and Viscosity on 3 Dimensional Pulsating Heat Pipe

Since the development of Pulsating Heat Pipe (PHP), it has gained a lot of attention in the field of thermal management. Flow inside multi-turn PHP is dominated by the capillary action mostly driven by the surface tension and drag force. Cetyltrimethyl ammonium chloride (CTAC) surfactant solution has lower surface tension and higher viscosity values compared to water, its base fluid. Experimental results have proven that the thermal resistance of PHP has increased its thermal performance at higher fill ratios and higher heat input, however the operational mechanism is not yet understood. Vapor formation, its movement and flow pattern of phases of working fluid can be well analyzed by the computational approach. In this paper, results of numerical analysis of 3-D PHP with working fluids that has values of surface tension and viscosity equal to that of 2000 ppm of CTAC are presented to validate the experimental results, thereby explain the thermodynamic reason of decreased thermal resistance. Moreover, the reasons for degraded performance of PHP with CTAC solutions at lower fill ratio and lower heat inputs are explained based on the vapor generation and flow of liquid-vapor inside the capillary tube. The numerical investigation was carried out for the case of 35%, 50% and 65% Fill Ratios (FR) at heat supply of 20, 30, 40 and 50 Watts. Lower surface tension promoted the phase change by rapid formation of vapor from liquid phase. Higher viscosity decreased the velocity of the fluid within the pipe. Influence of surface tension and viscosity on the thermal performance of PHP varied with different fill ratios and heat input.

Experiments on the breakup of drop-impact crowns by Marangoni holes

We investigate experimentally the breakup of the Edgerton crown due to Marangoni instability when a highly viscous drop impacts on a thin film of lower-viscosity liquid, which also has different surface tension than the drop liquid. The presence of this low-viscosity film modifies the boundary condition, giving effective slip to the drop along the solid substrate. This allows the high-viscosity drop to form a regular bowl-shaped crown, which rises vertically away from the solid and subsequently breaks up through the formation of a multitude of Marangoni holes. Previous experiments have proposed that the breakup of the crown results from a spray of fine droplets ejected from the thin low-viscosity film on the solid, e.g. Thoroddsen et al. (J. Fluid Mech., vol. 557, 2006, pp. 63–72). These droplets can hit the inner side of the crown forming spots with lower surface tension, which drives a thinning patch leading to the hole formation. We test the validity of this assumption with close-up imaging to identify individual spray droplets, to show how they hit the crown and their lower surface tension drive the hole formation. The experiments indicate that every Marangoni-driven patch/hole is promoted by the impact of such a microdroplet. Surprisingly, in experiments with pools of higher surface tension, we also see hole formation. Here the Marangoni stress changes direction and the hole formation looks qualitatively different, with holes and ruptures forming in a repeatable fashion at the centre of each spray droplet impact. Impacts onto films of the same liquid, or onto an immiscible liquid, do not in general form holes. We furthermore characterize the effects of drop viscosity and substrate-film thickness on the overall evolution of the crown. We also measure the three characteristic velocities associated with the hole formation: i.e. the Marangoni-driven growth of the thinning patches, the rupture speed of the resulting thin films inside these patches and finally the growth rate of the fully formed holes in the crown wall.

Effects of Spacer Length on the Surface Properties of Cationic Gemini Fluorosurfactants

A novel class of cationic gemini fluorosurfactants with different spacer and same hydrophobic chain were synthesized. They were structurally characterized by NMR (1H and 19F), FT-IR, ESI-MS and elemental analysis. The equilibrium surface tensions were studied. The results showed that the gemini fluorosurfactants with the shorter spacer displayed higher surface activity, lower surface tension (21.48 mN/m) can be reached. Besides, the synergistic properties of these synthesized gemini fluorosurfactants with sodium dodecyl benzene sulfonate (SDBS) were investigated.

Surface tension of two weakly interacting liquid alloys

We report surface tension of two weakly segregating alloys Al-Ga and Cd-In in molten state at temperatures of 1023 K and 800 K respectively using different approaches. Our analysis based on different assumptions reveal that the metal with lower surface tension tends to segregate on the surface of molten alloy and the metal with higher surface tension tends to segregate in the bulk. Different approaches predict consistency in the values of the surface tension of Al-Ga liquid alloy that increases with increase in bulk concentration of aluminium in the alloy with all values smaller than the ideal values. In Cd-In alloy the models reveal no such regularity in the surface tension; it varies slightly from the ideality. DOI: http://dx.doi.org/10.3126/bibechana.v9i0.7183 BIBECHANA 9 (2013) 103-112

Effects of Surface Tension on Drop Impact on a Horizontal Rotating Disk

The impact processes of water and ethanol drops on a rotating horizontal aluminum disk were recorded and analyzed using a high-speed digital camera together with an image analysis program. The angular velocities of the disk were altered to study the effect of surface tension of drops on drop impact processes. The experimental results show that a lower surface tension will result in a higher tangential spread factor and a lower receding rate during the receding stage, for the drop impinging and depositing on a rotating disk. In addition, a lower surface tension of the drop tends to promote the occurrence of splash. The experimental results further verify a proposed correlation of splash-deposition boundary for drops impinging on a rotating disk. Both drops, though they have a quite different surface tension, experience four stages, with two new stages different from those of drops impinging on stationary surfaces. Their tangential spreading factors both increase obviously with the tangential velocity at the impact point, while their radial spreading factors vary a little.