Effect of Tricarboxylic Acids on the Formation of Hydrogels with Melem or Melamine: Morphological, Structural and Rheological Investigations

Herein, aggregation behaviors of melem or melamine in the presence of three symmetric carboxylic acids (1,3,5-tris(4-carboxyphenyl)benzene (TPCA), 1,3,5-benzene-tri-carboxylic acid (BTA) and 1,3,5-cyclohexane-tri-carboxylic acid (CHTA)) have been performed to check the influence of acid on the formation of aggregated structures which have been investigated by optical microscopy, FESEM, FTIR, XRD and viscoelastic properties have been explored with rheological studies. Interestingly, melem, that has limited solubility in aqueous medium, forms aggregation that leads to the formation of hydrogels with TPCA. More significantly, hydrogel is formed here by matching the size selectivity. Melem forms hydrogel with only large tricarboxylic acid, whereas melamine produces hydrogel with any kind of its counterpart from small to large tricarboxylic acid derivatives. Present investigations and results provide the strategy of design of organic self-assembled materials having two component systems.

Fractal Dimension Analysis to Detect the Progress of Cancer Using Transmission Optical Microscopy

Fractal dimension, a measure of self-similarity in a structure, is a powerful physical parameter for the characterization of structural property of many partially filled disordered materials. Biological tissues are fractal in nature and reports show a change in self-similarity associated with the progress of cancer, resulting in changes in their fractal dimensions. Here, we report that fractal dimension measurement is a potential technique for the detection of different stages of cancer using transmission optical microscopy. Transmission optical microscopy of a thin tissue sample produces intensity distribution patterns proportional to its refractive index pattern, representing its mass density distribution. We measure fractal dimension detection of different cancer stages and find its universal feature. Many deadly cancers are difficult to detect in their early to different stages due to the hard-to-reach location of the organ and/or lack of symptoms until very late stages. To study these deadly cancers, tissue microarray (TMA) samples containing different stages of cancers are analyzed for pancreatic, breast, colon, and prostate cancers. The fractal dimension method correctly differentiates cancer stages in progressive cancer, raising possibilities for a physics-based accurate diagnosis method for cancer detection.

Investigation of solder beading phenomenon under surface-mounted electrolytic capacitors

Purpose The purpose of this paper is to study the solder beading phenomenon (referring to larger-sized solder balls) of surface-mounted electrolytic capacitors. Solder beading could induce failures by violating the minimal electrical clearance on the printed circuit board (PCB). In modern lead-free reflow soldering, especially in high-reliability industries, such as automotive, aeroplane and aerospace, detecting and preventing such defects is essential in reliable and cost-effective manufacturing. Design/methodology/approach The large size of the involved components may block the view of automatic optical inspection; therefore, X-ray inspection is necessary. To detect the failure mode, X-ray imaging, cross-section grinding, optical microscopy and Fourier transformed infrared spectroscopy were used. High-resolution noncontact profilometry and optical microscopy were used to analyse component designs. The surface mounting process steps were also analysed to reveal their dependence on the issue. Test methods were designed and performed to reveal the behaviour of the solder paste (SP) during the reflow soldering process and to emphasise the component design relevance. Findings It was found that the reduction of SP volume only reduces the failure rate but does not solve the problem. Results show that excessive component placement pressure could induce solder beading. Statistical analysis revealed that differences between distinct components had the highest effect on the solder beading rate. Design aspects of solder beading-prone components were identified and discussed as the primary source of the problem. Practical implications The findings can be applied in surface-mount technology production, where the total failure count and resulting failure costs could be reduced according to the findings. Originality/value This paper shows that component design aspects such as the low distance between the underside of the component and the PCB and blocked proper outgassing of volatile compounds of the SP can be root causes of solder beading under surface-mounted electrolytic capacitors.

Исследование процесса коалесценции капель эмульсии в неоднородном переменном электрическом поле при наличии межфазной асфальтеновой пленки на границе раздела масло-вода

The behavior of a water-in-oil emulsion stabilized with asphaltenes under the action of an inhomogeneous alternating electric field has been studied. The experimental technique is based on the use of microfluidics, optical microscopy, and high-speed video filming. Quantitative estimates of the parameters characterizing the dynamics of the destruction of the emulsion, depending on the frequency and amplitude of the applied field, are obtained. The method will be useful in the development of effective methods for breaking emulsions and modifying existing technologies for separating oil emulsions into phases.

Orientation Patterns Characteristic for the Structure of the Ceramic Body of Wheel-thrown Pottery

The described analysis follows recent findings related to the orientation of particles and voids in a ceramic body that is characteristic for wheel-made pottery. The analysis is focused on the potential variability within wheel-throwing method and is based on an experimental collection that combines the factors of the experience and motor habits of individual potters and the vessel shape. The orientation of the components of a ceramic body is calculated for two sections: radial and tangential. The sections are analysed using optical microscopy. The calculated orientation and alignment reflect the throwing style of potters using the same forming method.

Knowledge Acquisition and Satisfaction of Virtual Microscopy Usage Among Medical Students of Universiti Sains Malaysia

The virtual microscope has been employed as an adjunct tool to teach optical microscopy for histology learning in medical schools. However, there is no reliable evidence in the literature that virtual and optical microscopy impacts students’ learning. This study focuses on comparing two different methods in learning histology in Universiti Sains Malaysia, namely virtual microscopy and optical microscopy, with regard to medical students’ knowledge acquisition and satisfaction levels. A total number of 120 medical students, consisting of 53 first-year and 67 second-year students, were recruited. The students were divided into virtual microscopy and optical microscopy groups. During the one-day intervention, all students attended a pre-requisite lecture on “Histology of the Eye”, a slide demonstration and a hands-on session using a designated microscope. Students’ knowledge acquisition was evaluated through a pre- and post-practical evaluation and their satisfaction level on learning histology using respective learning tools was measured. The study revealed that the optical and virtual microscopy groups showed significant improvement from the pre- to post-practical tests scores with p < 0.001, respectively. However, the mean increment was higher in virtual microscopy (38.51%) than in optical microscopy (35.08%). Furthermore, the virtual microscopy group had a significantly higher satisfaction score towards the learning tool than the optical microscopy group, p = 0.008. The knowledge acquisition of the virtual microscopy group was equal to the optical microscopy group as they were shown to have a similar improvement in the test scores, comprehension level and learning ability. However, students were nonetheless satisfied with the usage of virtual microscopy as a learning tool.

The influence of carbon-containing, magnetic and nano-dispersed additions on structure and electrophysical properties of polypropylene-based composite monofibers

There were PP- and iron-containing, fibrous, carbon- and nanodispersed-addition-based composite fibers prepared. There were addition content equals of 5.0%mass. There were blend of isotactic PP and addition homogenized in melt with one-screw lab extruder. There were zonal temperature on extruder equals of 230-250 o C. There were strangs receiving in bath of water and threated with knife granulation. Then, there were granules drying on air during 5h, and, then in thermal vacuum oven at 80±5 o C during 3h. Then, there are monofiber of 1 mm’s diameter formed on lab stand. Then, from one formed those others monofibers of different values of spinneret drawing (Фв, %). There were Фв for monofibers equals of 300 and 500%. Then, there were formed monofibers threated with thermoorientational drawing process at 150 oC. Then, there were monofibers of Фв value, which equals of 300%, drawn till draw degree λ=6, but, those others of Фв value, which equals of 500% - to λ=4. It is succeed, for composite monofibers, that orientational drawing process has had realized, until to the same value, as well as for one of virgin PP. But, when at formation and thermoorientational drawing processes, there were placing much number of breaks, as compared with monofiber of pure PP. When studying the structure with SEM technique, there was revealed microfibrillar structure of composite monofiber. When using optical microscopy, then there was determined irregularity for distribution of addition’s particles, leading to disproportional distribution of tension values at loading. It is revealed, for composite monofiber, at given value for content of addition, that electrical conductivity phenomenon is absent here. There are real ε’and imaginal ε’’ parts of complex dielectrical permittivity phenomenon, on frequency of 9 GHz, equals of 2.1 and 0.2, accordingly. It is established, that pure, non-drawn and composite monofiber itrinsically have satisfactory magnetic properties (σs=0.5 Gs∙cm3/g, Hc= 695 E). There are real μ’ and imaginal μ’’ parts of complex magnetical permittivity phenomenon equals of 1.1 and 0.02, accordingly.