Prevention Of Segregation Research Articles

Effect of Particle Interactions on the Assembly of Drying Colloidal Mixtures.

The effects of particle interactions on the size segregation and assembly of colloidal mixtures during drying were investigated. A cationic surfactant was added to a binary latex/silica colloidal dispersion that has been shown to self-stratify upon drying at room temperature. Atomic force microscopy was used to show that the change in particle interactions due to the presence of surfactants reduced the degree of stratification and, in some cases, suppressed the effect altogether. Colloidal dispersions containing higher surfactant concentrations can undergo a complete morphology change, resulting instead in the formation of armored particles consisting of latex particles coated with smaller silica nanoparticles. To further prove that armored particles are produced and that stratification is suppressed, cross-sectional images were produced with energy-dispersive X-ray spectroscopy and confocal fluorescence microscopy. The growth of armored particles was also measured using dynamic light scattering. To complement this research, Brownian dynamics simulations were used to model the drying. By tuning the particle interactions to make them more attractive, the simulations showed the presence of armored particles, and the size segregation process was hindered. The prevention of segregation also results in enhanced transparency of the colloidal films. Overall, this research proves that there is a link between particle interactions and size segregation in drying colloidal blends and provides a valuable tool to control the assembly of different film architectures using an extremely simple method.

‘Mentally, we’re rather country people’ – planssplaining the quest for urbanity in Helsinki, Finland

ABSTRACT This paper explores the concept of urbanity in a specific context, namely Helsinki, Finland. In a European context, Finland urbanized late. This lies at the heart of the common interpretation that Finland lacks an urban culture and urban lifestyles. Today, however, with the new comprehensive Urban Plan, city planners in Helsinki emphasize a paradigm shift towards urbanity. This paper seeks to understand this changing emphasis in planning by exploring how planners frame and understand urbanity. The paper concludes that within the Nordic welfare context more emphasis is needed to rethink whom urbanity serves and how it resonates with the prevention of segregation that the city also aims at.

Evaluation of a Dry Coating Technology as a Substitute for Roller Compaction for Dry Agglomeration Applications in the Pharmaceutical Industry

A dry coating technology has been evaluated as a dry agglomeration technique for a typical pharmaceutical formulation. Its efficiency was compared with that of the more commonly used roller compaction dry granulation. A commercially available system was selected as a representative technology. The selection was based on batch size, processing time, unit size, vendor support, preventive maintenance requirements, development stage, and maturity for pharmaceutical industry requirements. The comparison targets the behavior of the resulting materials in terms of flowability, compressibility, mixing efficiency, and prevention of segregation. Particle size distribution, bulk density, scanning electron microscopy, FT4 powder rheometer, and hardness were used for the characterization of the powders. A design of experiment was used to evaluate the impact of the dry coating equipment operating parameters (rotor speed and processing time) as well as the impact of formulation (grade of microcrystalline cellulose and ratio between dibasic calcium phosphate and lactose). The tested dry coating technology shows (1) an improved compressibility, (2) that the powders are homogenous, and (3) that they do not have a tendency to segregate in downstream process steps and during handling and storage. The impact of the rotor speed is proven statistically not significant, but it seems that a lower rotor speed might lead to less attrition and better flow properties. Processing time does not seem to have an impact for the range of processing times evaluated. Compared to roller compaction, the main advantages of the tested technology are the shape and surface enhancement and the absence of work hardening. This work has shown that the blends produced by the targeted dry coating equipment has equal or better results than the powders processed by roller compaction for all the critical quality attributes that were evaluated.

The Complex Support and Assistance to Children with Disability and their Families in the Czech Republic and the Presentation of Case Final Reports on Early Care of Client as an Example of Good Practice

Abstract The theme of the paper is very topical in global and European context. It brings theoretical information on the concept of asocial model of early care in the Czech Republic and practical case studies and final reports related to the early care provision which demonstrate tangible activities within the system of the complex support and assistance to children with disability and their families. The author applies the theoretical-practical approach as she is of the opinion that „the practice without theory is as a blind person on the road and the theory without practice is as a cart without an axle”. The aim of the paper is to extend theoretical information on the topic in the Czech Republic by individual examples of final reports related to the provision of social prevention of the early care in the Czech Republic. The overall aim of the paper is to justify topicality and eligibility of early care in its broad reference framework, including its practical impact. The theoretical basis of the paper is elaborated with respect to the analysis and comparison of Czech and foreign literature, legislation, methodology document and other relevant written resources. The practical level is elaborated with respect to 3 cases and final reports of the provider of an early care of the social prevention. The early care in the Czech Republic represents a professional, modern and recognized system in European and global comparison and is legally anchored in the Act 108/2006 Coll. on social services. It aims on the minimization of child´s disability impact upon child´s development, especially the social inclusion of a child and a family and their capability to cope with limitating disability in natural environ, i.e. by the preservation of standard way of life. It represents a multi-dimensional model, overcoming limitation of sectoral division of the early care and facilitating complex assistance from a series of subject fields at the same time. Services for families with an endangered child in early age are the background for social, educational and pedagogical inclusion of a child and the re-socialisation and re-inclusion of a family. Early care is considered preventive, from the point of the prevention of the second disability (i.e. is effective), in the prevention of institutionalized and asylum care (i.e. is economical), in the prevention of segregation (i.e. is ethical).

СУЧАСНИЙ СТАН СТВОРЕННЯ, ВИРОБНИЦТВА ТА ДОСЛІДЖЕННЯ ТАБЛЕТОВАНИХ ЛІКАРСЬКИХ ПРЕПАРАТІВ Повідомлення 19. Сучасний стан розробки та дослідження мультипартикулярних пелетних систем.

<p align="center"><strong>MODERN STATE OF CREATION, PRODUCTION AND RESEARCH OF DRUGS</strong></p><p align="center"><strong>M</strong><strong>.</strong><strong>B</strong><strong>. </strong><strong>Demchuk</strong><strong>, </strong><strong>S</strong><strong>.</strong><strong>M</strong><strong>. </strong><strong>Gureyeva</strong><strong><sup>1</sup></strong><strong>, </strong><strong>T</strong><strong>.</strong><strong>A</strong><strong>. </strong><strong>Hroshovyi</strong><strong></strong></p><p>TernopilStateMedicalUniversityby I.Ya. Horbachevsky</p><p><sup>1</sup>JSC “Farmak”</p><p><strong>Noti</strong><strong>ce</strong><strong> 19.</strong> The current state of development and research of multiple unit pellet systems.</p><p><strong>Summary: </strong>the literature on technological aspects of creations of pellets, features of compression pellet to obtain multiple unit pellet systems are summarized<strong>.</strong></p><p><strong>Keywords: </strong>pellets, methods of pellets, pellet pressing, multiple unit pellet systems.</p><p><strong>Introduction. </strong>Oral modified-release multiple-unit dosage forms have always been more effective therapeutic alternative to conventional or immediate release single-unit dosage forms. With regards to the final dosage form, the multiparticulates are usually formulated into single-unit dosage forms such as filling them into hard gelatin capsules or compressing them into tablets.</p><p>Pelletization is a technique that enables the formation of spherical beads or pellets with a mean diameter usually ranging from 0.5 to2.0 mm. These pellets can evantually be coated and very often used in controlled-release dosage forms. The use of pelletization and pellets leads to an improvement in the flowability, appearance and mixing properties, thus avoiding excessive dust and reducing segregation and, generally, eliminating undesirable properties and improving the physical or chemical properties of fine powders.</p><p>The pharmaceutical industry has developed a great interest in pelletization due to a variety of reasons:</p><p>– prevention of segregation of co-agglomerated components, resulting in an improvement of the uniformity of the content;</p><p>– prevention of dust formation;</p><p>– increasing bulk density and decreasing bulk volume;</p><p>– the defined shape and weight improves the appearance of the product;</p><p>– improvement of the handling properties, due to the free-flowing properties;</p><p>– improvement of the hardness and friability of pellets;</p><p>– controlled release application of pellets due to the ideal low surface area-to-volume ratio that provides an ideal shape for the application of film coatings.</p><p>Pellets are prepared by different techniques, such as extrusion and spheronisation, rotogranulation, solution, suspension or powder layering, spray-drying or spray-congealing.</p><p>Extrusion / spheronisation is a multistage process for obtaining pellets with uniform size from wet granulates (extrudates). The process is more labour-intensive and more expensive than the conventional wet-granulation technique, as its use should be limited only to the production of spherical pellets for controlled release of drugs.</p><p>The fluid-bed granulation consists in the spraying of a granulation solution onto the suspended particles, which then are dried rapidly in the hot air stream.</p><p>Rotogranulation is one of the most recent methods for the production of spheroids. The single-unit spheronizing system can be described using terms like centrifugal granulator, rotary fluidized-bed granulator, rotary fluid bed, rotary processor or rotor granulator.</p><p>Layering a suspension or a solution of a drug on a seed material (usually, a coarse crystal or nonpareil) can produce pellets that are uniform in size distribution and generally posess very good surphace morphology. These characteristics are especially desirable when pellets will be coated for the purpose of achieving a controlled release.</p><p>Dry powder layering is similar to the solution or suspension layering. Instead of these dispersions, the layering is performed using a drug powder.</p><p>Spray-drying represents another process with limited application in the development of pharmaceutical pelletized products, based on globulation. During spray-drying, a drug solution or suspension is sprayed, with or without excipients, into a hot-air stream, generating dry and highly spherical particles.</p><p>Spray-congealing (spray-chilling) is a technique similar to spray-drying. Spray-congealing is a process in which a drug is allowed to melt, disperse or dissolve in hot melts of gums, waxes, fatty acids or other melting solids. The dispersion is then sprayed into a stream of air and other gases with a temperature below the melting point of the formulation components.</p><p><strong>Conclusions.</strong> The basic requirements and approaches to development multiple unit pellet system, aspects and examples receipt of pellets and tablets based on them are described.</p>

Processes of phase instability in high-temperature steels subjected to long-term heating

The phase composition and properties of martensitic steels of the Fe-C-Cr-Ni-Co-Mo-W-Nb system are studied. The nature of phase instability in long-term heating in the temperature range of 450–600°C is determined. The effect of concentration and kinetic factors on the formation of Laves, α-Cr, and σ-phases is considered. Recommendations are given on prevention of segregation of phases negatively influencing the impact toughness and corrosion resistance of the studied steels.

キルン内の原料移動および温度分布

In the previous paper we described the installation of a multi-purpose 46 m long kiln with 6 sampling holes and the method of taking samples from a reducing kiln while it is in operation, then showed some results of measuring works.In this paper we discuss the travel of material and distribution of its temperature. Many literatures are found which investigate the transportation of raw materials, through a rotary kiln in the field of cement industry. From the viewpoint of roasting reaction, the material is composed of a single element for a cement kiln; however, it is always a mixture of 2 elements 'which consist of reducing agent and substrate for a reducing kiln. Then if segregation occurs between 2 elements, it means an interruption of reducing reaction in the kiln.So the segregation of material is one of the most important facts in the reducing kiln.After various experiments, researches and observations, we reach the following conclusions;(1) Segregation occurs because of different repose angles of material grain.(2) Travelling speed of grain through the rotary kiln is decided by the filling ratio of charge and its local position in the bed.(3) The grain of iron sand is so fine, and the reducing agent is not so fine, and as the result, the reducing agent has tendency to segregate outside of bed. We call it belt type segregation.(4) Belt type segregation grows into rippling distribution across the axis of kiln, we call it striped segregation.It is necessary for reductive roasting with kiln to control the grain size of charge material. In the future reports we shall analyse the segregation quantitatively again.Generally, a reductive kiln has three zones by the name of drying, heating and reducing zone. Measured distribution of material temperature is almost linear throughout its length, and the rate of heat transfer in the last zone by means of improvement on heat transmission and prevention of segregation in charge material.

Purification and Prevention of Segregation in Single Crystals of Germanium

Purification and Prevention of Segregation in Single Crystals of Germanium