Scattering Properties of a Suspension Containing Plate-like Particles and Their Aggregates

The results of the scattering matrix measurements at a wavelength of 0.63 μm are presented for an aqueous suspension of lead oxide containing plate-like particles and their aggregates with monomers dimensions of ∼ 5 nm. The results of the measurements are compared with the matrix calculations for axially symmetric scatterers (ellipsoids of revolution). It is shown that the presence of aggregates affects the scattering properties of such a medium. The particles size distribution of the dispersed medium was found by solving the problem of minimizing the sum of the squares of the deviations of the experimental values of the matrix elements from calculated using the model of axially symmetric scatterers. It is demonstrated that the particle size distribution is more accurately retrieved by minimizing the sum of the squares of the deviations for the sum of the diagonal elements. The obtained distribution is compared with one measured by the dynamic light scattering method.     Keywords: scattering matrix, aggregates, particle size distribution, axially symmetric scatterers, dynamic light scatterin

Моделирование влияния проточного устройства анализа качества молока на поток в доильной установке

The development of dairy farming proves to require technologies for rapid and non-destructive analysis of milk quality. It is noted that optical methods do not negatively affect dairy products. It is noted that farms may get the desired technology by upgrading milking machines with a flow-through device for milk quality express analysis. (Research purpose) To study the effect of upgrading the milking machine with a flow-through device for milk quality express analysis on the flow of the milk-air mixture in the milk hose. (Materials and methods) For this purpose the SolidWorks simulation modeling was used. Both the developed device and the simulation model are made in cylindrical geometry to ensure their compatibility with the milk hoses of 14 millimeters in diameter.  The measurement took into account the angular distribution of light scattered by milk flowing inside an optically transparent cylindrical glass tube. The flow of the milk-air mixture was affected only by a change in the inner diameter of the milk tubes. (Results and discussion) It is noted that the simulation model demonstrates an increase in the flow rate of the milk-air mixture in the areas of flow transition between the milk hose and the fitting (to a smaller internal diameter), as well as between the fitting and the measuring chamber of the device (to a larger internal diameter). The mirror result is recorded at the flow outlet from the measuring chamber to the nozzle and the transition from the nozzle to the milk hose. (Conclusions) It is found that the use of the device results in a 14 percent increase in the average flow rate of 0.3-0.7 meters per second. It is determined that due to the incomplete filling of the milk hose during milking, the difference in the flow rates of the milk-air mixture before and when applying the device does not have any adverse impact on the milking machine operation. The feasibility of upgrading the milking machine with a flow-through device for milk quality express analysis is proved.Показали, что для развития молочных ферм необходимы технологии  быстрого  и неразрушающего  анализа качества молока. Отметили, что оптические методы не влияют на молочную продукцию. Подчеркнули, что модернизация доильных установок  проточным устройством  экспресс-анализа качества молока позволит обеспечить  ферму необходимой технологией. (Цель исследования) Изучить влияние проточного устройства  экспресс-анализа качества молока на поток молоковоздушной смеси,  протекающей в молочном шланге. (Материалы и методы)  Использовали имитационное моделирование в программе SolidWorks. Разработанное устройство,  как и имитационную модель, выполнили в цилиндрической геометрии для совместимости  с молочными шлангами диаметром 14 миллиметров. При измерении учитывали угловое  распределение света,  рассеянного  молоком, которое протекает внутри оптически прозрачной цилиндрической стеклянной трубки. На протекание потока молоковоздушной  смеси влияло только изменение внутреннего  диаметра молочных трубок. (Результаты и обсуждение) Отметили, что имитационная модель продемонстрировала увеличение скорости потока молоковоздушной смеси в областях перехода потока между молочным шлангом и штуцером (на меньший внутренний диаметр), а также между штуцером и измерительной камерой устройства (на больший внутренний диаметр). Зеркальный результат зафиксировали при выходе потока из измерительной камеры в штуцер и переходе из штуцера в молочный шланг. (Выводы) Выявили, что наличие устройства повышает среднюю скорость потока, равную 0,3-0,7  метра в секунду, на 14 процентов. Определили, что из-за неполного заполнения молочного шланга при доении разница скоростей потока молоковоздушной смеси до и после устройства  не оказывает негативного влияния на работу доильной установки. Доказали, что возможна модернизация доильной установки проточным устройством  экспресс анализа качества молока

Scattering Properties of a Suspension Containing Plate-Like Particles and their Aggregates

The results of the scattering matrix measurements at a wavelength of 0.63 μm are presented for an aqueous suspension of lead oxide containing plate-like particles and their aggregates with monomers dimensions of ~ 5 nm. The results of the measurements are compared with the matrix calculations for axially symmetric scatterers (ellipsoids of revolution). It is shown that the presence of aggregates affects the scattering properties of such a medium. The particles size distribution of the dispersed medium was found by solving the problem of minimizing the sum of the squares of the deviations of the experimental values of the matrix elements from calculated using the model of axially symmetric scatterers. It is demonstrated that the particle size distribution is more accurately retrieved by minimizing the sum of the squares of the deviations for the sum of the diagonal elements. The obtained distribution is compared with one measured by the dynamic light scattering method. Keywords: scattering matrix, aggregates, particle size distribution, axially symmetric scatterers, dynamic light scatterin

Scattering Properties of A Suspension Containing Plate-like Particles and Their Aggregates

The results of the scattering matrix measurements at a wavelength of 0.63 μm are presented for an aqueous suspension of lead oxide containing plate-like particles and their aggregates with monomers dimensions of ∼ 5 nm. The results of the measurements are compared with the matrix calculations for axially symmetric scatterers (ellipsoids of revolution). It is shown that the presence of aggregates affects the scattering properties of such a medium. The particles size distribution of the dispersed medium was found by solving the problem of minimizing the sum of the squares of the deviations of the experimental values of the matrix elements from calculated using the model of axially symmetric scatterers. It is demonstrated that the particle size distribution is more accurately retrieved by minimizing the sum of the squares of the deviations for the sum of the diagonal elements. The obtained distribution is compared with one measured by the dynamic light scattering method.     Keywords: scattering matrix, aggregates, particle size distribution, axially symmetric scatterers, dynamic light scatterin

Long-living nanobubbles of dissolved gas in aqueous solutions of salts and erythrocyte suspensions

Results of experiments combining laser modulation interference microscopy and Mueller matrix scatterometry show that macroscopic scatterers of light are present in liquids free of external solid impurities. Experimental data on distilled water and aqueous NaCl solutions of various concentrations as well as physiological saline solution are reported. The experimental data can be interpreted by using a model of micron-scale clusters composed of polydisperse air nanobubbles having effective radii of 70-100 nm. Their concentration increases with the growth of ionic content. We hypothesize that under certain conditions those clusters of nanobubbles can affect the erythrocyte structure

Nafion Swelling in Salt Solutions in a Finite Sized Cell: Curious Phenomena Dependent on Sample Preparation Protocol

When a membrane of Nafion swells in water, polymer fibers “unwind” into the adjoining liquid. They extend to a maximum of about ~300 μm. We explore features of Nafion nanostructure in several electrolyte solutions that occur when the swelling is constrained to a cell of size less than a distance of 300 μm. The constraint forces the polymer fibers to abut against the cell windows. The strongly amphiphilic character of the polymer leads to a shear stress field and the expulsion of water from the complex swollen fiber mixture. An air cavity is formed. It is known that Nafion membrane swelling is highly sensitive to small changes in ion concentration and exposure to shaking. Here we probe such changes further by studying the dynamics of the collapse of the induced cavity. Deionized water and aqueous salt solutions were investigated with Fourier IR spectrometry. The characteristic times of collapse differ for water and for the salt solutions. The dynamics of the cavity collapse differs for solutions prepared by via different dilution protocols. These results are surprising. They may have implications for the standardization of pharmaceutical preparation processes

Formation of Water-Free Cavity in the Process of Nafion Swelling in a Cell of Limited Volume; Effect of Polymer Fibers Unwinding

When Nafion swells in water, colloidal particles are repelled from the polymer surface; this effect is called the formation exclusion zone (EZ), and the EZ size amounts to several hundred microns. However, still no one has investigated the EZ formation in a cell whose dimension is close to the EZ size. It was also shown that, upon swelling in water, Nafion fibers “unwind” into the water bulk. In the case of a cell of limited volume, unwound fibers abut against the cell windows, and water is completely pushed out from the region between the polymer and the cell window, resulting in a cavity appearance. The temporal dynamics of the collapse of this cavity was studied depending on the cell size. It is shown that the cavity formation occurs due to long-range forces between polymer strands. It turned out that this scenario depends on the isotopic composition of the water, ionic additives and water pretreatment. The role of nanobubbles in the formation and collapse of the cavity were analyzed. The results obtained allowed us to conclude that the EZ formation is precisely due to the unwinding of polymer fibers into the liquid bulk

New Structural Nanocomposite Based on PLGA and Al₂O₃ NPs as a Balance between Antibacterial Activity and Biocompatibility with Eukaryotic Cells

Development of eco-friendly and biodegradable package materials is an important goal of modern science and international industry. Poly(lactic)-co-glycolic acid (PLGA) is suitable for this purpose. However, biocompatible materials may be contaminated with bacteria. This problem may be solved by the addition of metal oxides nanoparticles (NPs) with antibacterial properties. Although metal oxides NPs often show cytotoxicity against plant and mammalian cells, a new nanocomposite based on PLGA and aluminum oxide (Al2O3) NPs has been developed. The PLGA/Al2O3 NP composite has pronounced antibacterial properties. The addition of Al2O3 NPs 0.01% inhibited growth of E. coli for >50%. The antimicrobial effect of Al2O3 NPs is implemented through the generation of reactive oxygen species and damage of bacterial proteins and DNA. The biocompatibility of the nanocomposite with plant and mammalian cells was studied. The PLGA/Al2O3 NP composite did not influence the growth and development of tomatoes and cucumbers. PLGA and its composite with Al2O3 NPs 0.001–0.1% did not influence viability and proliferation of mammalian cells, on their density or substrate colonization rate. The developed nanocomposite has controlled mechanical properties, high antibacterial activity and high biocompatibility, which makes it an attractive candidate for building and food package material manufacture and agriculture