Search results for "Digest"

Tailoring the microstructure and mechanical properties of Ti–Al alloy using a novel electromagnetic stirring method

2006

The effect of melt convection during the solidification of Ti45Al55 alloys was investigated in terms of microstructure evolution and the resulting mechanical properties. The samples were subjected to conventional induction melting as well as enhanced melt stirring by an external magnetic field using a specially designed floating zone arrangement. The stirred samples showed a significant improvement of plastic deformability. A strong change in the morphology from dendritic to spherical and an increased properitectic phase fraction were observed after stirring.

Adsorption Active Diblock Copolymers as Universal Agents for Unusual Barrier-Free Transitions in Stimuli-Responsive Brushes

2021

We reconsider a recently proposed design for smart responsive brushes, which is based on a conformational transition in very dilutely embedded block copolymers with a surface active block (Qi et al., Macromolecules 53, 5326, 2020). Under certain conditions, the transition acquires an unusual character: it remains very sharp, but the barrier separating the adsorbed and desorbed states disappears completely. We show that these features are very robust with respect to changing almost all system parameters: the lengths of the inert and active blocks of the minority chain, the brush length, its density, and its polydispersity. The only relevant condition is that the inert block of the minority c…

Rapid Production of Internally Structured Colloids by Flash Nanoprecipitation of Block Copolymer Blends.

2018

Colloids with internally structured geometries have shown great promise in applications ranging from biosensors to optics to drug delivery, where the internal particle structure is paramount to performance. The growing demand for such nanomaterials necessitates the development of a scalable processing platform for their production. Flash nanoprecipitation (FNP), a rapid and inherently scalable colloid precipitation technology, is used to prepare internally structured colloids from blends of block copolymers and homopolymers. As revealed by a combination of experiments and simulations, colloids prepared from different molecular weight diblock copolymers adopt either an ordered lamellar morph…

Direct determination by portable ED-XRF of mineral profile in cocoa powder samples

2019

Abstract The present study has exploited the rapidity of the analysis and the multi-elemental capability of the energy dispersive X- ray fluorescence (ED-XRF) technique for the mineral profile determination in cocoa powder. A fast, cheap and environmental sustainable method without reagent consumption or toxic waste generation has been proposed. The samples can be prepared in the form of pellets of 13 mm in diameter and 2–3 mm thickness. The different internal calibrations used by ED-XRF equipment did not provide accurate results when comparing the mineral profile with the concentration obtained by Inductively Couple Plasma Optical Emission Spectroscopy (ICP-OES) after microwave assisted di…

A biomimetic approach to ameliorate dental hypersensitivity by amorphous polyphosphate microparticles.

2016

Abstract Objective Dental hypersensitivity has become one of the most common and most costly diseases in the world, even though those maladies are very rarely life threatening. Using amorphous microparticles, fabricated from the natural polymer (polyphosphate), we intend to reseal the dentinal tubules exposed and reduce by that the hypersensitivity. Methods Amorphous microparticles (termed aCa-polyP-MP) were prepared from Na-polyphosphate (polyP) and CaCl 2 , then incubated with human teeth. The potential of the microparticles to plug the dentinal tubules was determined by microscopic and spectroscopic techniques. Results We demonstrate that, in contrast to polyP, the aCa-polyP-MP efficient…

Confinement-induced polymorphism in acetylsalicylic acid–nanoporous glass composites

2018

We report on the experimental observation of confinement-induced new phase appearance in acetylsalicylic acid (ASA)–porous glass (PG) composites. In this study, ASA was embedded in PG host matrices of various pore widths (15–200 nm). The Raman spectra and positron annihilation lifetime measurements exhibit the existence of ASA nanocrystals in the PG matrix. The DSC data revealed that the melting temperature TM and excess specific heat decrease with decreasing the size of embedded ASA nanocrystals. The close inspection of the TM dependence versus diameter of filled pores has shown that the ASA crystallizes in polymorph II in confined matrix. Moreover, it was demonstrated that the ASA spatial…

Determination of cobalt in foods by atomic absorption and inductively coupled plasma spectrometry (Short communication)

1988

Moisture loss, gain and migration in foods

2011

Abstract: The loss, gain and transfer of moisture often affect food materials. Whether arising from interaction with the atmosphere or with another component of the food, such changes always cause deterioration of the overall quality of the food through softening, toughening, breakdown, swelling or shrinkage due to phase transitions or dissolution. In most cases, water migration leads to organoleptic or microbiological changes in the food. With a view to better understanding the physical deterioration of food and to providing a tool for better control of food quality (and therefore of longer shelf life), this chapter reviews the water relationships in foods with particular attention to, and…

Real-space imaging and motion analysis in sheared colloidal crystals

2007

Microscopic imaging of single particles is a powerful tool to investigate the local structure of colloidal suspensions. For single-particle identification with high-resolution microscopy the resolution power is limited by refraction to roughly the wavelength of light. In this case the depth of sharpness is on a scale of less than this limit. For this reason the simultaneous observation of particles in two or more layers of a colloidal crystal seems to be impossible. We report a method with which we can image more than one particle layer in dilute colloidal suspensions with preserved resolution. The analysis of the images obtained, in particular for the investigation of crystal layer motion …

The role of mechanical properties of brittle airy foods on the masticatory performance

2010

This work investigates the mastication of two samples of typical cereal food products previously characterised by different sensory, textural and mechanical properties, by two complementary approaches. Electromyographic records and image analysis of chewed food particles first confirm the importance of the brittle behaviour of the products on human mastication. For both products, the fragmentation is followed by a significant agglomeration after less than 10 chewing cycles, both phenomena being correlated to the force magnitude and its evolution. Then, artificial mastication is undertaken to shed more light on the capability of the chewing simulator to discriminate both products under dry m…