A Novel High-Throughput Chaotic Advection Microreactor for the Preparation of Uniform BaSO4 Nanoparticles

Owing to high mixing efficiency, microreactors are used to synthesize uniform BaSO4 nanoparticles, but application in industrial scale is limited due to poor throughput. In this work, a high-throughput passive four-stage asymmetric oscillating feedback microreactor using chaotic mixing mechanism was developed to prepare BaSO4 nanoparticles of high size uniformity. Three-dimensional unsteady simulations showed that chaotic mixing could be induced by three unique secondary flows (i.e., vortex, recirculation, and oscillation), and the fluid oscillation mechanism was examined in detail. Simulations and Villermaux-Dushman experiments indicate that almost complete mixing in molecular level could be achieved when total volumetric flow rate Qtotal was larger than 10 mL/min, and the prepared BaSO4 nanoparticles were with narrow particle size distribution (PSD). Through the adjustment of Qtotal and reactant concentrations, it is easy to control the average size. An average size of 26 nm with narrow PSD could be achieved at Qtotal = 160 mL/min.

Modelling Thermal Conduction in Polydispersed and Sintered Nanoparticle Aggregates

Nanoparticle aggregation has been found to be crucial for the thermal properties of nanofluids and their performance as heating or cooling agents. Most relevant studies in the literature consider particles of uniform size with point contact only. A number of forces and mechanisms are expected to lead to deviation from this ideal description. In fact, size uniformity is difficult to achieve in practice; also, overlapping of particles within aggregates may occur. In the present study, the effects of polydispersity and sintering on the effective thermal conductivity of particle aggregates are investigated. A simulation method has been developed that is capable of producing aggregates made up of polydispersed particles with tailored morphological properties. Modelling of the sintering process is implemented in a fashion that is dictated by mass conservation and the desired degree of overlapping. A noticeable decrease in the thermal conductivity is observed for elevated polydispersity levels compared to that of aggregates of monodisperse particles with the same morphological properties. Sintered nanoaggregates offer wider conduction paths through the coalescence of neighbouring particles. It was found that there exists a certain sintering degree of monomers that offers the largest improvement in heat performance.

Quality Identification of Sauce-Flavor Liquor Based on the Tyndall Phenomenon

There is an obvious colloid state in sauce-flavor liquor due to its unique brewing process and long storage time, which is an important quality feature of sauce-flavor. Aiming at the problems of time, cost, and the strong professionalism of the traditional quality identification method, we proposed a method to identify the quality of sauce-flavored liquor based on the Tyndall phenomenon. The influence of different wavelengths of light on the light scattering in liquor was explored, and it was concluded that the ultraviolet and blue light bands have a certain efficiency in the identification of liquor. Additionally, we analyzed the relationship between the particle size uniformity of liquor colloids and liquor quality according to the Tyndall phenomenon. We found that higher quality liquor has a brighter and lighter Tyndall path and a smaller light flooding angle due to the uniformity of the particles in it. This method can be used to achieve qualitative identification and is suitable for the identification of sauce-flavored liquor.

Hydrothermal Synthesis of Biphasic Calcium Phosphate from Cuttlebone Assisted by the Biosurfactant L-rhamnose Monohydrate for Biomedical Materials

The motivation of this research work is to develop novel medical material from cuttlebone (calcium source) by L-rhamnose monohydrate (biosurfactant) for aged people. The process can be synthesized biphasic calcium phosphate which is eco-friendly to environment. One of the most important aspects for this work is to use cuttlebone as a naturally occurring calcium source from a local beach in Thailand. It usually contains 90% calcium carbonate. The objective of this research work is to synthesize the biphasic calcium phosphate by hydrothermal reaction. Critical micelle concentrations (CMCs) of 10, 20, 100, 500 and 1000 of L-rhamnose monohydrate were used to control particle size and shape. XRD revealed a mixture of β-tricalcium phosphate and hydroxyapatite powder. SEM reported that the size of particles can be effectively controlled by the addition of L-rhamnose monohydrate, and with the addition of surfactant, size uniformity was achieved. The cytotoxicity test was reported to be in the range of 70–75%. It was remarkable to note that biphasic calcium phosphate synthesized from cuttlebone with the aid of L-rhamnose monohydrate will be considered an excellent candidate as a scaffold material.

Design of a spray dedusting system with variable particle size

This paper proposes a spray control system with variable particle size to address the inaccuracy of droplet size control in the existing spray dedusting system. A PID control algorithm with stable air and water pressure is adopted to ensure droplet size uniformity. An experimental device of the droplet control system is built in the laboratory to verify the algorithm’s effectiveness. Experiments were conducted using PLC as the core controller to verify the influence of different types of nozzles on the droplet size under the same air pressure and water pressure through experiments. The results show: (1) the systems droplet size range is 8–200 μm, which meets the dust removal conditions of respirable dust and is suitable for dust removal. (2) When measured under identical experimental conditions, the droplet size decreases as the nozzle angle increases. It was shown that the spray system combined with various sprinklers can achieve full droplet size coverage and improve the efficiency of dust-fall. It provides a solution for the existing dust removal system to flexibly change the droplet size according to the dust size.

Development of a Simple Spheroid Production Method Using Fluoropolymers with Reduced Chemical and Physical Damage

Establishing an in vitro–based cell culture system that can realistically simulate in vivo cell dynamics is desirable. It is thus necessary to develop a method for producing a large amount of cell aggregates (i.e., spheroids) that are uniform in size and quality. Various methods have been proposed for the preparation of spheroids; however, none of them satisfy all requirements, such as cost, size uniformity, and throughput. Herein, we successfully developed a new cell culture method by combining fluoropolymers and dot patterned extracellular matrix substrates to achieve size-controlled spheroids. First, the spheroids were spontaneously formed by culturing them two-dimensionally, after which the cells were detached with a weak liquid flow and cultured in suspension without enzyme treatment. Stable quality spheroids were easily produced, and it is expected that the introduction and running costs of the technique will be low; therefore, this method shows potential for application in the field of regenerative medicine.

The Properties of OPEFB Cellulose Nanofibrils Produced by A Different Mode of Ultrafine Grinding

Cellulose Nanofibrils (CNFs) was resulted from deconstruction of the hierarchical structure of cellulose. CNFs are commonly obtained by mechanical fibrillation, such as ultrafine grinding processes and its variation. Nevertheless, the influence of different treatments on the properties of the resulting CNF especially from variety of ultrafine grinding mode has not been reported. This study investigates the properties of cellulose nanofibrils (CNF) produced from bleached pulp oil palm empty fruit bunch (OPEFB) Kraft pulp through an ultrafine grinder with two different treatments in the fibrillation process. These two treatments were: 1) ultrafine grinder with increasing gaps distances; -30, -50, -70, and -90 µm with five cycles in every gap, 2) ultrafine grinder on constant gaps (-30µm) with increasing grinding cycles: 5, 10, 15, 30, and 40 cycles through the grinder. The influence of the treatment was evaluated through particle size distribution, crystallinity index, and morphological properties. The result showed that the increasing gaps treatment efficiently improved the size uniformity of CNFs, length 147-139.5 nm, and scanning electron microscope micrograph confirmed that the diameter of CNF was smaller with the increasing grinding gaps than increasing grinding cycles. However, the increasing cycle’s treatment produced CNF with a higher crystallinity index. The crystallinity index (CrI) of the CNF decreased from 71.27 to 62.25% with increasing gaps, whereas the CrI of the CNF from increasing cycles was 69.35%. This study provides a valuable guideline for determining the appropriate process to produce CNF especially by mechanical grinding using ultrafine grinder from OPEFB according to the desired result.

COMPARISON OF HANDWRITING LEGIBILITY FOR MANUAL HANDWRITING AMONG TYPICALLY DEVELOPING INDIAN CHILDREN

Handwriting involves the integration of many skills, including perceptual motor skills, motor planning and cognition visual motor skills, as well as control of kinesthetic and tactile abilities to grasp and maintain control of the writing tool, as well as motor control The aim of this study was to compare the handwriting skills of typically developing Indian children on ETCH-M (Evaluation Tool Of Children Handwriting – Manuscript). A sample of 200 typically developing Indian children were included in the study using convenience sampling method. The age ranged from 6 years to 9 years. It was found that ETCH-M is an assessment tool which can assess the Handwriting skills of Indian typically developing children in 6-9 years of age group. Independent sample t- test was done to compare the mean raw score of each group. There was a significant difference with statistical value of p< 0.001. The handwriting evaluation depends upon six characteristics of writing: Handwriting legibility, letter formation, uniformity of letter size, uniformity of letter slant, spacing between letters and words, alignment of lines of writing. KEYWORDS: Handwriting, legibility, occupational therapy, vernacular medium.