Relevance of Dielectric Properties in Microwave Assisted Processes

Microwaves are electromagnetic radiation with wavelength ranging from 1 mm to 1 m in free space with a frequency from 300 GHz to 300 MHz, respectively. International agreements regulate the use of the different parts of the spectrum; the frequencies 915 MHz and 2.45 GHz are the most common among those dedicated to power applications for industrial, scientific and medical purposes (Metaxas & Meredith, 1983). Although microwaves have been firstly adopted for communications scope, an increasing attention to microwave heating applications has been gained since after World War II (Meredith, 1998; Chan & Reader, 2002). Reasons for this growing interest can be found in the peculiar mechanism for energy transfer: during microwave heating, energy is delivered directly to materials through molecular interactions with electromagnetic field via conversion of electrical field energy into thermal energy. This can allow unique benefits, such as high efficiency of energy conversion and shorter processing times, thus reductions in manufacturing costs thanks to energy saving. Moreover, other effects have been pointed out, such as the possibility to induce new structural properties to irradiated materials (development of new materials) and to apply novel strategies in chemical syntheses (green techniques). Crucial parameters in microwave heating are the dielectric properties of matter; they express the energy coupling of a material with electromagnetic microwave field and, thus, the heating feasibility (Metaxas & Meredith, 1983; Schubert & Regier 1995; Tang et al., 2002). On the bases of dielectric properties, microwave devices (applicators) can be adopted in heating operations and optimized working protocols can be used. This chapter is divided into four sections dealing with: i. fundamentals of microwave heating and relevance of dielectric properties of materials; ii. different techniques used in dielectric properties measurements of materials (test fixtures characteristics, technique applicability, advantages and disadvantages); iii. application of the open-ended coaxial-probe method in dielectric properties measurements of food, pharmaceutical ingredients, living materials, to understand specific heating phenomenology and, thus, to optimize thermal treatments / to define safety limits of exposition; iv. basics of heat and mass transfer modeling in microwave assisted processes

Disordered Rock-Salt Type Li2TiS3 as Novel Cathode for LIBs: A Computational Point of View

The development of high-energy cathode materials for lithium-ion batteries with low content of critical raw materials, such as cobalt and nickel, plays a key role in the progress of lithium-ion batteries technology. In recent works, a novel and promising family of lithium-rich sulfides has received attention. Among the possible structures and arrangement, cubic disordered Li(2)TiS(3) has shown interesting properties, also for the formulation of new cell for all-solid-state batteries. In this work, a computational approach based on DFT hybrid Hamiltonian, localized basis functions and the use of the periodic CRYSTAL code, has been set up. The main goal of the present study is to determine accurate structural, electronic, and spectroscopic properties for this class of materials. Li(2)TiS(3) precursors as Li(2)S, TiS(2), and TiS(3) alongside other formulations and structures such as LiTiS(2) and monoclinic Li(2)TiS(3) have been selected as benchmark systems and used to build up a consistent and robust predictive scheme. Raman spectra, XRD patterns, electronic band structures, and density of states have been simulated and compared to available literature data. Disordered rock-salt type Li(2)TiS(3) structures have been derived via a solid solution method as implemented into the CRYSTAL code. Representative structures were extensively characterized through the calculations of their electronic and vibrational properties. Furthermore, the correlation between structure and Raman fingerprint was established

An engineering approach to biomedical sciences: advanced strategies in drug delivery systems production

Development and optimization of novel production techniques for drug delivery systems are fundamental steps in the “from the bench to the bedside” process which is the base of translational medicine. In particular, in the current scenery where the need for reducing energy consumption, emissions, wastes and risks drives the development of sustainable processes, new pharmaceutical manufacturing does not constitute an exception. In this paper, concepts of process intensification are presented and their transposition in drug delivery systems production is discussed. Moreover, some examples on intensified techniques, for drug microencapsulation and granules drying, are reported

Nitrogen substitutional defects in silicon. A quantum mechanical investigation of the structural, electronic and vibrational properties

RD and FSG acknowledges the CINECA award (HP10CTG8YY) under the ISCRA initiative, for the availability of high performance computing resources and support.The vibrational infrared (IR) and Raman spectra of seven substitutional defects in bulk silicon are computed, by using the quantum mechanical CRYSTAL code, the supercell scheme, an all electron Gaussian type basis set and the B3LYP functional. The relative stability of various spin states has been evaluated, the geometry optimized, the electronic structure analyzed. The IR and Raman intensities have been evaluated analitically. In all cases the IR spectrum is dominated by a single N peak (or by two or three peaks with very close wavenumbers), whose intensity is at least 20 times larger than the one of any other peak. These peaks fall in the 645–712 cm−1 interval, and a shift of few cm−1 is observed from case to case. The Raman spectrum of all defects is dominated by an extremely intense peak at about 530 cm−1, resulting from the (weak) perturbation of the peak of pristine silicon.ISCRA initiative CINECA award (HP10CTG8YY); Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART

Droplet size prediction in the production of drug delivery microsystems by ultrasonic atomization

Microencapsulation processes of drugs or other functional molecules are of great interest in pharmaceutical production fields. Ultrasonic assisted atomization is a new technique to produce microencapsulated systems by mechanical approach. It seems to offer several advantages (low level of mechanical stress in materials, reduced energy request, reduced apparatuses size) with respect to more conventional techniques. In this paper the groundwork of atomization is briefly introduced and correlations to predict droplet size starting from process parameters and material properties are presented

Inside the Phenomenological Aspects of Wet Granulation: Role of Process Parameters

Granulation is a size-enlargement process by which small particles are bonded, by means of various techniques, in coherent and stable masses (granules), in which the original particles are still identifiable. In wet granulation processes, the powder particles are aggregated through the use of a liquid phase called binder. The main purposes of size-enlargement process of a powder or mixture of powders are to improve technological properties and/or to realize suitable forms of commercial products. A modern and rational approach in the production of granular structures with tailored features (in terms of size and size distribution, flowability, mechanical and release properties, etc.) requires a deep understanding of phenomena involved during granules formation. By this knowledge, suitable predictive tools can be developed with the aim to choose right process conditions to be used in developing new formulations by avoiding or reducing costs for new tests. In this chapter, after introductive notes on granulation process, the phenomenological aspects involved in the formation of the granules with respect to the main process parameters are presented by experimental demonstration. Possible mathematical approaches in the granulation process description are also presented and the one involving the population mass balances equations is detailed

Del preescolar a la escuela primaria

1 documento en PDF de 10 páginas.A veces la matemática se asocia con estereotipos escolares que están lejos de su esencia: fórmulas, ecuaciones y teoremas que para algunos son solo un aprendizaje memorístico y cálculos sin sentido; todo esto puede producir estupor y manifestaciones de desagrado ligadas a las experiencias de aprendizaje en los años de escuela. Este libro es pensado para ofrecer a los docentes un instrumento útil que los pueda acompañar en un itinerario de reflexión, tanto teórico como práctico, sobre la enseñanza-aprendizaje de la matemática en el preescolar.PREFACIO 1. Una educación matemática significativa en preescolar. Hipótesis teóricas, investigaciones empíricas y experiencias lúdicas Aprendizaje espontáneo de la matemática Algunos ejemplos, para iniciar Modelos mentales que se forman espontáneamente Ayudar a formar modelos correctos Características generales de los procesos de enseñanza-aprendizaje de la matemática en el preescolar Conocimientos a la base de las estrategias ingenuas que se establecen al hacer matemática Uso de estrategias ingenuas en el hacer matemática Algunas hipótesis de investigación en didáctica de la matemática en el nivel preescolar El “triángulo de la didáctica” Teoría de las situaciones. La microsociedad del salón de clase en el preescolar y las prácticas compartidas Obstáculos Ambientes artificiales de aprendizaje Investigación en didáctica de la matemática, “A” y “B” Referencias. 2. Propuestas de actividad en clase: aritmética y geometría Coplas infantiles y fábulas que incluyen números Números fabulosos La caza del número Números para jugar El calendario, momento de rutina y de matemática Los días del año Viajemos sobre un tapete mágico para descubrir juegos de pavimentación Un viaje a través de países coloridos El viaje continúa en busca de lugares artísticos Juguemos con pentaminos Referencias 3. Propuestas de actividad en clase: geometría, probabilidad, estadística Juegos con sólidos Las cajas abiertas Adivina qué es Pesos y balanzas Una historia, muchas elecciones: construcción de un libro en el cual las elecciones hechas influyen en la continuación del juego Una historia, muchas elecciones (segunda parte): juego con los dados para escoger las rutas adecuadas Camina, camina Las cartas de jueg

Prediction of early recurrent thromboembolic event and major bleeding in patients with acute stroke and atrial fibrillation by a risk stratification schema: the ALESSA score study

Background and Purposes—This study was designed to derive and validate a score to predict early ischemic events and major bleedings after an acute ischemic stroke in patients with atrial fibrillation. Methods—The derivation cohort consisted of 854 patients with acute ischemic stroke and atrial fibrillation included in prospective series between January 2012 and March 2014. Older age (hazard ratio 1.06 for each additional year; 95% confidence interval, 1.00–1.11) and severe atrial enlargement (hazard ratio, 2.05; 95% confidence interval, 1.08–2.87) were predictors for ischemic outcome events (stroke, transient ischemic attack, and systemic embolism) at 90 days from acute stroke. Small lesions (≤1.5 cm) were inversely correlated with both major bleeding (hazard ratio, 0.39; P=0.03) and ischemic outcome events (hazard ratio, 0.55; 95% confidence interval, 0.30–1.00). We assigned to age ≥80 years 2 points and between 70 and 79 years 1 point; ischemic index lesion >1.5 cm, 1 point; severe atrial enlargement, 1 point (ALESSA score). A logistic regression with the receiver-operating characteristic graph procedure (C statistic) showed an area under the curve of 0.697 (0.632–0.763; P=0.0001) for ischemic outcome events and 0.585 (0.493–0.678; P=0.10) for major bleedings. Results—The validation cohort consisted of 994 patients included in prospective series between April 2014 and June 2016. Logistic regression with the receiver-operating characteristic graph procedure showed an area under the curve of 0.646 (0.529–0.763; P=0.009) for ischemic outcome events and 0.407 (0.275–0.540; P=0.14) for hemorrhagic outcome events. Conclusions—In acute stroke patients with atrial fibrillation, high ALESSA scores were associated with a high risk of ischemic events but not of major bleedings

Health, education, and social care provision after diagnosis of childhood visual disability

Aim: To investigate the health, education, and social care provision for children newly diagnosed with visual disability.Method: This was a national prospective study, the British Childhood Visual Impairment and Blindness Study 2 (BCVIS2), ascertaining new diagnoses of visual impairment or severe visual impairment and blindness (SVIBL), or equivalent vi-sion. Data collection was performed by managing clinicians up to 1-year follow-up, and included health and developmental needs, and health, education, and social care provision.Results: BCVIS2 identified 784 children newly diagnosed with visual impairment/SVIBL (313 with visual impairment, 471 with SVIBL). Most children had associated systemic disorders (559 [71%], 167 [54%] with visual impairment, and 392 [84%] with SVIBL). Care from multidisciplinary teams was provided for 549 children (70%). Two-thirds (515) had not received an Education, Health, and Care Plan (EHCP). Fewer children with visual impairment had seen a specialist teacher (SVIBL 35%, visual impairment 28%, χ2p < 0.001), or had an EHCP (11% vs 7%, χ2p < 0 . 01).Interpretation: Families need additional support from managing clinicians to access recommended complex interventions such as the use of multidisciplinary teams and educational support. This need is pressing, as the population of children with visual impairment/SVIBL is expected to grow in size and complexity.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited