Plant-Derived Saponins: A Review of Their Surfactant Properties and Applications

Increasing environmental concern and consumer demand for natural, sustainable and eco-friendly products have prompted the replacement of synthetic surfactants with their natural plant-based alternatives. Saponins are the plant based natural surfactants characterized by their foam forming properties in aqueous solution. Their natural origin makes them eco-friendly, bio-degradable and non-toxic. Further, they possess better physicochemical properties than the syn-thetic ones. They are also reported to exhibit a lot of useful biological activities such as anti-cancer, antifungal, anti-inflammatory, antimicrobial, antioxidant and cholesterol-lowering properties. Because of their excellent surface activity, biological activities and wide distribution in nature, saponin rich plants deserve deeper insight as a sustainable source of natural surfactants as they possess the potential to replace toxic synthetic surfactants abundant today. This review article is intended to provide a brief overview on the saponins with a special notion on their surface-active properties. It encourages further studies on development of commercial formulations based on saponins for the complete replacement of the synthetic counter parts, making better use of plants sources thereby contributing to global agenda of green environment.

Process simulation-based evaluation of design and operational implications of water-laid paper machine conversion to foam technology

Foam forming technology has attracted much attention during the past few years in the paper industry. Its advantages compared to conventional water forming are a new product portfolio and increased process efficiency. To support the paper industry in pushing foam forming technology forward, process simulation is needed to provide supporting data for strategic decision-making and as a basis for equipment dimensioning. This study examined the conversion of an existing wallpaper machine from water to foam forming technology using process simulation. To determine the required process configuration and parameter changes in the existing process, both published and unpublished data on the foam forming process were collected. This paper also describes modeling of the foam phase in the selected simulation software. The suitability of existing paper process equipment for foam was analyzed. Simulations revealed that undisturbed operation with foam requires some equipment modifications and re-arrangements in water circuits. With foam forming, the water balance in both short and long circulation changes remarkably compared to conventional water forming, leading to a large increase in the long circulation volume flows.

Genome Editing to Generate Sake Yeast Strains with Eight Mutations That Confer Excellent Brewing Characteristics

Sake yeast is mostly diploid, so the introduction of recessive mutations to improve brewing characteristics requires considerable effort. To construct sake yeast with multiple excellent brewing characteristics, we used an evidence-based approach that exploits genome editing technology. Our breeding targeted the AWA1, CAR1, MDE1, and FAS2 genes. We introduced eight mutations into standard sake yeast to construct a non-foam-forming strain that makes sake without producing carcinogens or an unpleasant odor, while producing a sweet ginjo aroma. Small-scale fermentation tests showed that the desired sake could be brewed with our genome-edited strains. The existence of a few unexpected genetic perturbations introduced during breeding proved that genome editing technology is extremely effective for the serial breeding of sake yeast.

EXAMINATION OF HEAT EXCHANGE IN A POROUS DUST-GAS CATCHER WITH A RING-PIPE SPRAYER

Nozzle-free capillary-porous dust and gas trap with foam generating and defoaming structures was developed and studied. Foam flow is generated by dusty gas, micro and ultra microscopic particles, which are especially dangerous for human body, are cleaned. Stability of liquid film in the porous structure during supply of foam-forming liquid by a spray in the form of a tubular ring, was determined. Foam generating and defoaming structures have been optimized, due to this material consumption and dimensions are reduced by 2-2.5 times, hydraulic resistance - by dozens of times (up to one hundred times), and gas-dynamic - by up to two times.

Sound absorption properties of wood-based pulp fibre foams

In this study, sound absorbing materials were produced through foam forming technique using hardwood and softwood pulps with varying chemical composition, ultrastructural, and morphological properties as raw materials. The sound absorption properties of the produced foams were measured and related to the ultrastructure and the morphology of the pulp fibres. All the fibre foams provided sound absorption properties comparable to those of conventional porous materials used for acoustic purposes. In general, further processing, as well as smaller fibre dimensions contribute to improve the sound absorption properties of the pulp fibre foams. The results provide valuable insight on the optimization of wood-based sound absorbing materials. Graphic abstract

Characteristics of heat protection properties of foam forming systems in fighting fires on tankers

The article considers means of fighting fires on tankers carrying oil products. The foam hydro monitors are considered the effective means for fighting a fire on tankers, their positive and negative sides are described after using on the merchant ships. A number of experiments have been carried out to obtain adequate models of the heat-shielding properties of foamed films. Investigations on modern foam-forming systems, which are actively used on ships carrying oil products during fire extinguishing are presented. The criteria have been analyzed that should be taken into account to obtain a model of the heat-shielding action of foaming agents. A model of heat protective effect of foaming agents has been modeled. Sodium silicate was chosen as the main foaming element. After using sodium silicate in different concentrations, it was combined with different samples of seawater (from the Dead Sea, the Black Sea and the Mediterranean Sea). When mixing a foaming agent with a mass content of 2.5% with water from the Black and Mediterranean Seas, the volume of the obtained foam makes less than 30%. It has been inferred that using seawater as a foaming catalyst for binary foaming systems is available. There was conducted an experiment for determination of corrosion which was carried out using fragments of the walls of tanks made of steel grade Ст 3 with 5 mm thick. There has been defined the average rate of weight loss per unit area of metal plates when they are exposed in the investigated aqueous solution. There has been substantiated availability of using sea water as a foam catalyst for binary foam-forming systems.

Analysis of the foam-forming of non-woven lightweight fibrous materials using X-ray tomography

Foam-forming has in the past predominantly been used to create two-dimensional sheet-like fibrous materials. Allowing the foam to drain freely and decay under gravity, rather than applying a vacuum to remove it rapidly, we can produce lightweight three-dimensional fibrous structures from cellulose fibres, of potential use for thermal and acoustic insulation. $$\mu$$ μ CT scanning of the fibrous materials enable us to determine both void size distributions and also distributions of fibre orientations. Through image analysis and uniaxial compression testing, we find that the orientation of the fibres, rather than the size of the voids, determine the compressive strength of the material. The fibrous samples display a layering of the fibres perpendicular to the direction of drainage of the precursor liquid foam. This leads to an anisotropy of the compressive behaviour of the samples. Varying the initial liquid fraction of the foam allows for tuning of the compressive strength. We show an increase in over seven times can be achieved for samples of the same density (13 kg.m-3). Graphic abstract