Seshadri Ramkumar

Study of the effect of sliding velocity on the frictional properties of nonwoven fabric substrates

Frictional properties of nonwoven substrates have been investigated using a sliding friction apparatus. Nonwoven substrates were developed using a modern needle-punching nonwoven technology. The experiment was conducted over a range of applied normal loads. The study was aimed at understanding the effect of testing speeds on the frictional properties of needle-punched nonwoven substrates. Frictional properties were characterized using friction factors, C, n and R. Results indicate that as the speed of the testing increased, frictional resistance increased.

Mobility of polyaromatic hydrocarbons (PAHs) in soil in the presence of carbon nanotubes

Being a potential risk to the environment, a fate study of carbon nanotube (CNT) in the environment is urgently needed. A study of CNT impacts on the bioavailability of other conventional contaminants in a terrestrial system is particularly rare. This study explored PAH leaching behaviors in the presence of CNTs with column leaching tests. Four PAHs (Naphthalene, fluorene, phenanthrene, and pyrene), three CNTs (f-SWNTs, MWNTs, f-MWNTs), and a sandy loam soil were involved in this study. We found that at a concentration of 5mg/g, CNTs could significantly retain PAHs in soil. Such a strong PAH retention was caused by low mobilities of CNTs and their strong PAH sorption capacities. This study illustrated that the properties of both sorbents (e.g. available surface area and micropore volume) and sorbates (e.g. hydrophobicity and molecular volume) influenced the mobility of PAHs in soil.

Atmospheric pressure plasma treatment and breathability of polypropylene nonwoven fabric

Atmospheric pressure plasma treatment is a surface modification technique, which can be used for surface finishing and pretreatment of textiles using a broad range of reactive gases. In this study, atmospheric pressure plasma was created using a mixture of nitrogen and oxygen and was applied to polypropylene spunbond fabric. Physical properties like moisture vapor transport, pore size distribution and tensile strength were evaluated to understand the effect of the plasma treatment on spunbond polypropylene. Chemical composition of the fabric before and after plasma treatment was analyzed by Fourier transform infrared spectroscopy. The spectra showed that oxygen and nitrogen containing groups were generated on the surface of the plasma-treated fabric. Scanning electron microscope was used to observe the surface morphology of the substrate. It is evident from the capillary flow porometer results, pore size increased after plasma treatment resulting in enhanced moisture vapor transport rate. No significant decrease in breaking load was observed after the plasma treatment.

Nanomaterials for Defense Applications

Nanotechnology has found a number of applications in electronics and healthcare. Within the textile field, applications of nanotechnology have been limited to filters, protective liners for chemical and biological clothing and nanocoatings. This chapter presents an overview of the applications of nanomaterials such as nanofibers and nanoparticles that are of use to military and industrial sectors. An effort has been made to categorize nanofibers based on the method of production. This chapter particularly focuses on a few latest developments that have taken place with regard to the application of nanomaterials such as metal oxides in the defense arena.

Developments in Decontamination Technologies of Military Personnel and Equipment

Individual protection is important for warfighters, first responders and civilians to meet the current threat of toxic chemicals and chemical warfare (CW) agents. Within the realm of individual protection, decontamination of warfare agents is not only required on the battlefield but also in laboratory, pilot plants, production and agent destruction sites. It is of high importance to evaluate various decontaminants and decontamination techniques for implementing the best practices in varying scenarios such as decontamination of personnel, sites and sensitive equipment.

The Influence of Soil pH on the Uptake of Silver Nanoparticles in a Terrestrial System

The production and use of silver nanoparticles (Ag NPs) are increasing in the United States and across the globe. The Ag NPs may enter the terrestrial ecosystem with the application of sewage sludge as a fertilizer on agricultural farms. The present study investigated the influence of soil pH on the uptake of Ag NPs by insects. Two insects A. domesticus and T. molitor were selected for the experiment. The insects were exposed to Ag NPs under different soil pH including: 5, 6, 7, 8 (control), and 9. The Ag NPs were characterized prior to the study with transmission electron microscopy, dynamic light scattering, and powder X-ray diffraction techniques. The concentration of silver in insects was measured with inductively coupled plasma-optical emission spectroscopy. Increased levels of silver in insects was observed in normal and alkaline soil as compared to acidic soil treatment groups. Additionally, there was no significant difference due to insect species in the silver uptake.

Cellulose Monolith with Tunable Functionality for Immobilization of Influenza Virus

Advancements in influenza virus or virus like particle separation technology can greatly accelerate vaccine production. Due to frequent mutation of the influenza virus, rapid and effective separation of influenza virus directly from host cells still remains a challenge. In this paper, we developed a new cellulose fiber monolith-based chromatography with tunable anion exchange and pseudo-affinity modifications for the separation of cell cultureproduced influenza virus. A novel strategy is proposed for preparing cellulose fiber monolith, which enhances the mechanical property of the monolith. Controllable pore size and porosity were achieved by dispersing and removing a porogen into cellulose-dissolving solution. The structure of cellulose monolith was characterized by Scanning Electron Microscope and the porosity study, which confirmed the controllable average pore size of 10 micron and porosity up to 85%. Two virus separation modes including anion-exchange and pseudo-affinity were introduced into the cellulose monolith, subsequently. The two modifications were quantified by an Element Analyzer. A H1N1 influenza virus strain (A/WSN/33) was produced and harvested in adherent Madin-Darby Canine Kidney Epithelial (MDCK) cells and used directly for virus separation. The results indicated that the pseudo-affinity mode had higher virus separation efficiency and had less host cell dsDNA and protein contamination.

Advances in materials for chemical, biological, radiological and nuclear (CBRN) protective clothing

Abstract: Chemical, biological and nuclear (CBN) threats are still a major challenge faced by civilized nations. As these threats have become unconventional these days, solutions to tackle them should also be unconventional in nature. In other words, it is not possible for a single discipline to come up with a solution to counter CBN threat agents. In the CBN defense program, there are three main aspects, which include: 1) sensing the threat agents; 2) protection from the threat agents; and 3) preserving after attacks. Fibrous materials can be involved in all three aspects of CBN counter-measures. This chapter briefly discusses the characteristics of the CBN threat agents and their counter-measure strategies involving textile materials. New developments such as dry decontamination wipes and nanotechnology-based protective materials are highlighted in this chapter.