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Air borne particulate matter (PM) depending on size, shape, concentration, and chemical composition can cause multitude of health issues. In this study, we report the morphological study of dust samples obtained from twenty different locations of Kathmandu valley by imaging the sample directly by a bright field optical microscope. We find that the average size of particles in all the samples examined below 10 micrometer. Individual examination of particles revealed that significant number of particles asymmetric. The observation of asymmetric particles having aspect ratio as high as 20 may suggest that asbestiform particles exist in all the dust samples examined.   BIBECHANA 16 (2019) 41-46

Handmade papers (HPs) are fabricated from fibrous biomass of Lokta bushes and other plant species following traditional eco-friendly method in Nepal. Although HP fabricated from Lokta bushes is believed to be durable and resistant to bugs and molds, material properties of this paper are not reported in literature. In this study, we measured several material properties of 10 handmade Lokta paper samples collected from local enterprises and paper industries. The mean caliper, grammage, apparent density, equilibrium moisture content, Cobb 60, brightness, opacity, tensile strength, and tensile index values in the paper samples ranged from ∼90 to 700 μm, 50 to 150 g/m 2 , 0.2 to 0.4 g/cm 3 , 4 to 7%, 50 to 400 g/m 2 , 56 to 67%, 83 to 98%, 30 to 2900 N/m, and 1 to 27 Nm/g, respectively. These properties suggested that the HPs are lightweight papers with intermediate to high strength. The tensile strength was found to be significantly higher along the length direction ( p < 0.05). Characteristic features of cellulose, hemicellulose, and lignin were observed in FTIR spectra. The crystalline and amorphous phases were also identified in X-ray diffraction (XRD) data. Electron microscopy images revealed a nicely cross-linked network of intact fibers having almost parallel arrangement of microfibrils. These features could provide strength and durability to the paper samples. Understanding the material properties of HPs down to the sub-microscopic level may help improve the paper quality and find novel applications in the future.

We report facile methods of preparing nanosized hydrotalcite-like compounds, the layered double hydroxides (LDH), with ordinary chemistry laboratory settings to educate the young scientists from high schools to undergraduate university level fostering their research interest in preparing these nanomaterials of practical importance. Coprecipitation and urea hydrolysis methods have been recommended as facile routes of preparing the magnesium-aluminum layered double hydroxides (Mg-Al LDHs). The LDH thus prepared were characterized by Fourier transform infrared (FTIR) spectroscopic and powder X-ray diffraction (XRD) techniques. The observed weakening of some FTIR peaks and XRD planes shifting concerning standard JCPDS 89-5434 data implied the slight structural variation of the compounds and the presence of impurities. The average grain diameter of LDH particles was found in the range of 20 to 60 nm.

Micro-fibrous materials are one of the highly explored materials and form a major component of composite materials. In resource-limited settings, an affordable and easy to implement method that can characterize such material would be important.In this study, we report on a smartphone microscopic system capable of imaging a sample in transmission mode. As a proof of concept, we implemented the method to image handmade paper samples-cellulosic micro-fibrous material of different thickness. With 1 mm diameter ball lens, individual cellulose fibers, fiber web, and microporous regions were resolved in the samples. Imaging performance of the microscopic system was also compared with a commercial bright field microscope. For thin samples, we found the image quality comparable to commercial system. Also, the diameter of cellulose fiber measured from both methods was found to be similar. We also used the system to image surfaces of a three ply surgical facemask. Finally, we explored the application of the system in the study of chemical induced fiber damage.This study suggested that the smartphone microscope system can be an affordable alternative in imaging thin micro-fibrous material in resource limited setting.