Influence of rheological features of behaviour of the porous damaged materials on their indentation process

На основі теорії пластичності пористого тіл за допомогою комп'ютерного моделювання методом скінчених елементів досліджується напружено-деформований стан поблизу сферичного і конічного індентора при різних властивостях индентованого матеріалу. Аналізується розподіл густини в околі індентора в залежності від властивостей пористого тіла та умов тертя між індентором та пористим тілом. Наводяться діаграми навантаження в залежності від схильності до дилатансії та зовнішнього тертя. Приділено увагу виникненню та формі навалів навколо индентора.The purpose of this work was research of the main features of behavior of the porous and damaged powder based materials at indentation process. The mechanical behavior of such materials is characterized by a loosening at purely shift tension and asymmetry of a response to stretching and compression. The rheological model of plasticity of porous materials with imperfect interpartial contacts which was earlier proposed one of authors is considered. Based on such theory of plasticity for porous media with distributed damages using finite element computer simulation the deformed state near spherical and conical indenter for different mechanical properties of indented material and different friction conditions between indenter and porous body has been studied. Porosity distribution near indenter depending on properties of porous body and friction conditions between indenter and porous body has been analyzed. Load profiles as a function of dilatancy tendency and contact friction has been shown. Development of bulk around indenter and its shape has been investigated.На основе теории пластичности пористого тела с помощью компьютерного моделирования методом конечных элементов исследуется напряженно-деформированное состояние вблизи сферического и конического индентора при различных свойствах индентируемого материала. Анализируется распределение плотности в окрестности индентора в зависимости от свойств пористого тела и условий трения между индентором и пористым телом. Приводятся диаграммы нагружения в зависимости от склонности к дилатансии и внешнего трения. Уделяется внимание возникновению и форме навалов вокруг индентора

Osmolality of Commonly Used Oral Medications in the Neonatal Intensive Care Unit.

OBJECTIVE: The administration of hyperosmolar oral products in neonates has been associated with gastrointestinal complications. The American Academy of Pediatrics recommends a maximum osmolality of 450 mOsm/kg for formulas and enteral nutrition for term infants, and recent studies reported intolerance to enteral nutrition with osmolality above 500 mOsm/kg in low birthweight infants. The osmolality of medications administered to neonates is often not available in the literature or from manufacturers. The purpose of this study was to determine the osmolality of oral medications commonly administered to neonates in the NICU. METHODS: Fifty-two oral medications were chosen for this study, including solutions, suspensions, syrups, elixirs, and intravenous solutions administered orally. The osmolality of each medication was measured in triplicate by using freezing point depression. RESULTS: Thirty-seven of the 43 medications with measurable values (86.1%) had an osmolality greater than 500 mOsm/kg, and 6 medications (14%) had an osmolality less than 500 mOsm/kg. Nine medications did not result in a value. CONCLUSIONS: Our study provides osmolality data on oral medications commonly used in neonates with most oral medications having an osmolality greater than 500 mOsm/kg

Field-Assisted Sintering Technology / Spark Plasma Sintering: Mechanisms, Materials, and Technology Developments

Field-assisted sintering technology/Spark plasma sintering is a low voltage, direct current (DC) pulsed current activated, pressure-assisted sintering, and synthesis technique, which has been widely applied for materials processing in the recent years. After a description of its working principles and historical background, mechanical, thermal, electrical effects in FAST/SPS are presented along with the role of atmosphere. A selection of successful materials development including refractory materials, nanocrystalline functional ceramics, graded, and non-equilibrium materials is then discussed. Finally, technological aspects (advanced tool concepts, temperature measurement, finite element simulations) are covered

Emerging Nanotechnology in Chronic Respiratory Diseases

A large population, including people of all age groups, is suffering from chronic respiratory diseases worldwide. Asthma, chronic obstructive pulmonary disease, occupational lung diseases, cystic fibrosis, etc. are the most common of these diseases and are noncurable with conventional and currently available therapies. Nanotechnology is emerging as a great therapeutic promise in different spheres including drug delivery systems and is becoming the technology of choice nowadays. The administration of drugs via inhalation helps in avoiding the first-pass metabolism by targeted delivery to the affected site. It has been observed that there is a huge diversity in nanotechnology being used in pulmonary diseases, and thus safety assessment is a challenging as well as important task. The present review focuses on some of the major emerging nanotechnologies for chronic pulmonary diseases and includes some of the latest studies in the field of nanomedicines