Approaches for substrate functionalisation with silver nanoparticles

Functionalization of titanium substrates with silver nanoparticles (AgNPs) was carried out by sessile droplet, dip-coating and EPD approaches. According the SEM results the most effective methods of surface functionalization was EPD. The PVP-stabilized AgNPs were synthesized in aqueous solutions with a diameter of the metallic core of 70 ± 20 nm, negative charge of -15 mV

Novel Bicomponent Functional Fibers with Sheath/Core Configuration Containing Intumescent Flame-Retardants for Textile Applications

The objective of this study is to examine the effect of intumescent flame-retardants (IFR's) on the spinnability of sheath/core bicomponent melt-spun fibers, produced from Polylactic acid (PLA) single polymer composites, as IFR's have not been tested in bicomponent fibers so far. Highly crystalline PLA-containing IFR's was used in the core component, while an amorphous PLA was tested in the sheath component of melt-spun bicomponent fibers. Ammonium polyphosphate and lignin powder were used as acid, and carbon source, respectively, together with PES as a plasticizing agent in the core component of bicomponent fibers. Multifilament fibers, with sheath/core configurations, were produced on a pilot-scale melt spinning machine, and the changes in fibers mechanical properties and crystallinity were recorded in response to varying process parameters. The crystallinity of the bicomponent fibers was studied by differential scanning calorimetry and thermal stabilities were analyzed by thermogravimetric analysis. Thermally bonded, non-woven fabric samples, from as prepared bicomponent fibers, were produced and their fire properties, such as limiting oxygen index and cone calorimetry values were measured. However, the ignitability of fabric samples was tested by a single-flame source test. Cone calorimetry showed a 46% decline in the heat release rate of nonwovens, produced from FR PLA bicomponent fibers, compared to pure PLA nonwovens. This indicated the development of an intumescent char by leaving a residual mass of 34% relative to the initial mass of the sample. It was found that the IFRs can be melt spun into bicomponent fibers by sheath/core configuration, and the enhanced functionality in the fibers can be achieved with suitable mechanical properties

Practical aspects of improvement in methodics and organization of the audit of operations with investment property in Ukraine

Рассматриваются отдельные вопросы усовершенствования методики и организации аудита операций с инвестиционной недвижимостью (далее по тексту – ИН). Анализируются соответствующие нормы действующего законодательства Украины, регламентирующие аудиторскую деятельность. Дается характеристика основных задач, которые решаются при осуществлении аудита операций с ИН. Автором предлагается использование типовой программы аудита операций с ИН, предоставляется ее характеристика и описание, обозначаются основные этапы проведения аудита операций с ИН. Рассматривается необходимость осуществления процедур контроля качества аудиторских услуг в соответствии с требованиями норм обязательных к использованию в Украине Международного стандарта контроля качества 1 (далее по тексту МСКК 1 [1]) и Положения по национальной практике контроля качества аудиторских услуг 1, утвержденного Решением Аудиторской палаты Украины от 27.09.2007 г. № 182/4 (далее по тексту ПНПКК 1 [2]).Some issues of improvement methodology and organization of audit operations with investment property are considered (hereinafter – IP) and the relevant norms of Ukrainian legislation what govern audit activity are analyzed. There is the description of the main problems to be solved during the audit operations with IP. The author proposes to use of the standard audit program of operations with IP, provides its characteristics and description and designates the main stages of the audit operations with IP. The need for the implementation of quality control procedures for audit services in accordance with the requirements of the mandatory use in Ukraine with the International Standard on Quality Control 1 (hereinafter ISQC 1 [1]) and the Regulation on national practices in quality control of audit services 1, approved by the Audit Chamber of Ukraine from 27.09.2007 № 182/4 are considered (hereinafter RNPQC 1 [2])

Melt-spun polyamide-filaments with TiO2-nanoparticles: influence on thermal conductivity and tensile strength

Toplinska vodljivost termoplastičnih materijala može se povećati dodatkom nanočestica u polimer. Ispitane su različite vrste čestica titanijevog dioksida koje se razlikuju po svojoj površini. Također je mijenjana količina TiO2 od 0 do 20 mas. % jer je potreban kompromis između povećane toplinske vodljivosti, smanjene čvrstoće i krutosti do kojih dolazi zbog povećanja koncentracije čestica. Ispitan je također način miješanja i utjecaj disperzanta na disperziju čestica u polimernoj matrici. Između ostalog, utvrđeno je da količina od 20 mas. % TiO2 u PA 6 uzrokuje povećanje toplinske vodljivost od 26 %. Utvrđeno je da se PA 6 filamenti s 5 mas. % TiO2 mogu ispredati iz taline. Mehanička svojstva ovih modificiranih filamenata su dovoljno prikladna za daljnju tekstilnu obradu.One solution for increasing the thermal conductivity of thermoplastics is adding nanoparticles to the polymer. Various titanium dioxide particle types are tested, which differ in their surface area. Also the amount of TiO2 is varied between 0 wt-% and 20 wt-%, because a compromise is needed between increased thermal conductivity and reduced strength and rigidity caused by increasing the concentration of particles. Furthermore, the way of compounding and the influence of dispersant on the particle dispersion in the polymer matrix are examined. Inter alia it could be determined that an amount of 20 wt-% TiO2 in polyamide 6 leads to an increase of thermal conductivity of 26 %. It can be shown that polyamide 6-filaments with 5 wt-% TiO2 can be melt spun. The mechanical properties of these modified filaments are still high enough for further textile treatment

Structure of salts solution in polar dielectric liquids and electrically induced separation of solvated ions

The aim of study is to demonstrate that separation of solvated ions in solution of mix of salts under the action of external periodic electric field happens because of around ions there are formed clusters consisting of molecules of solvent and the sizes of such clusters have dimensions ~ 0.1 [mu]m. In investigations the sizes of clusters theoretically were defined and experimentally value of frequency of external electric field which action excites the effect of separation of the solvated ions was defined. Experiments were done in the Technical Physics Chair of the National Research Tomsk Polytechnic University. At theoretical determination of the dimensions of clusters Poisson's equation was solved and was considered that polar molecules of solvent are oriented under the action of electric field of an ion. The chemical composition of samples of solutions was determined by means of the spectrophotometry and he X-ray excited fluorescent radiation analysis method. Theoretical estimates and results of experiments confirmed the assumption that clusters which are formed around ions in solutions have the dimensions ~ 0.1 [mu]m. Results of investigation testify that placing of volume distributed electric charge of ion in dielectric liquid is accompanied by formation of the supramolecular particles, which we called "clusters", linear sizes of which is significantly more than first and second radiuses of solvation (~ 1 Angstrom) and reach size ~ 0.1 [mu]m. At such sizes inertial properties of clusters and their natural frequencies give the chance to operate their movement by means of action of external electric field on solution

Виды дефектов и расчет ущербов от отказов турбогенераторов на блоках электростанций

Оценка технологических и эксплуатационных рисков отказов электрооборудования выполняется на базе анализа статистических данных, но не лабораторных исследований. Оценка опасности возникновения дефектов позволяет оптимизировать график ремонтов и повышает безопасность эксплуатации изношенного электрооборудования

Cellulose aerogel micro fibers for drug delivery applications

Textile engineering can offer a multi-scale toolbox via various fiber or textile fabrication methods to obtain woven or nonwoven aerogels with different structural and mechanical properties to overcome the current limitations of polysaccharide-based aerogels, such as poor mechanical properties and undeveloped shaping techniques. Hereby, a high viscous solution of microcrystalline cellulose and zinc chloride hydrate was wet spun to produce mono and multi-filament alcogel microfibers. Subsequently, cellulose aerogel fibers (CAF) were produced and impregnated with model drugs using supercritical CO2 processes. Fibers were characterized in terms of morphology and textural properties, thermal stability, mechanical properties, and in vitro biological and drug release assessments. Loaded and non-loaded CAFs proved to have a macro-porous outer shell and a nano-porous inner core with interconnected pore structure and a specific area in the range of 100–180 m2/g. The CAFs with larger diameter (d ~ 235 μm) were able to form knitted mesh while lower diameter fibers (d ~ 70 μm) formed needle punched nonwoven textiles. Humidity and water uptake assessments indicated that the fibrous structures were highly moisture absorbable and non-toxic with immediate drug release profiles due to the highly open interconnected porous structure of the fibers. Finally, CAFs are propitious to be further developed for biomedical applications such as drug delivery and wound care

Интеграция различных САПР конструкторской подготовки производства по изделиям машиностроения в рамках единого информационного пространства на базе PDM-системы “SEARCH”

Обґрунтована необхідність iнтeгpaції різних САПР конструкторської підготовки виробництва по виробах машинобудування в рамках єдиного інформаційного простору. Підкреслено, що інформація, одержана з конструкторських САПР, є базовою для автоматизованих систем технологічної підготовки виробництва. Показані шляхи реалізації поставлених завдань на прикладі конструкторсько-технологічних служб ВАТ “Азовмаш”.A necessity is grounded integration different CAD of designer preproduction on wares engineer within the framework of single informative space. Underline, that the information got from designers CAD, are technological preproduction base for the automated systems. The ways of realization of the set problems are rotined on the example of design-engineering services of JSC “Azovmash

Slits in parabolic reflector antennas.

Diffraction by slits and scattering by antennas with slits in their reflectors are investigated. Attempts are made to engineer nulls in the rear radiation patterns of relatively small (ten wavelength) aperture reflector antennas by changing the size and position of slits in the reflectors. Diffraction by sharp edges are considered using a modified form of the Geometrical Theory of Diffraction and also reflector surface currents are studied from an integral equation standpoint via the Method of Moments and hybridised forms of the Method of Moments. Both amplitude and phase of electromagnetic fields are measured the use of a Microwave Homodyne Detection System, and experimental results are presented along with theoretical results