Spectroscopic studies of laser generated plasma X-rays and their effects on polymeric materials

Surface modification of polymers by X-rays produced from laser plasma can put a wide range of changes and are magnificently used in effectively all industries ranging from coatings, semiconductors, household appliances, automotive, and biomedical implants. Polymeric materials commonly have outstanding bulk physical and chemical properties. Different properties like electrical, chemical and physical properties can be modify when an extreme dose of X-rays is exposed on the surface of polymers. Currently X-rays are irradiated on the surface of two different polymers including polypropylene and polyethylene. These X-rays are detected with pin photodiode (BPX-65), generated from laser generated Cu plasma where Nd: YAG laser (1064 nm, 10 mJ) is focused on copper. Polymer surface is exposed to X-rays by different shots of laser which are varied from 100 to 400 with a gap of 100. Morphological structure has been studied by using optical microscopy and four point probes are used for studying the resistivity and conductivity. It has been observed that irradiation of X-rays from laser produced plasma produce changes in the bonding structure of polymers due to cross linking and chain-seasoning which are highly responsible for breakage or formation of a bond. A similar type of a result is deduced from four-point probe method that the resistivity of polymers is decreased due to the breakage of the H-C bond

Carbon Nanotube Reinforced High Density Polyethylene Materials for Offshore Sheathing Applications

Multiwall carbon nanotube (CNT)-filled high density polyethylene (HDPE) nanocomposites were prepared by extrusion and considered for their suitability in the offshore sheathing applications. Transmission electron microscopy was conducted to analyse dispersion after bulk extrusion. Monolithic and nanocomposite samples were subjected to accelerated weathering and photodegradation (carbonyl and vinyl indices) characterisations, which consisted of heat, moisture (seawater) and UV light, intended to imitate the offshore conditions. The effects of accelerated weathering on mechanical properties (tensile strength and elastic modulus) of the nanocomposites were analysed. CNT addition in HDPE produced environmentally resilient nanocomposites with improved mechanical properties. The energy utilised to extrude nanocomposites was also less than the energy used to extrude monolithic HDPE samples. The results support the mass substitution of CNT-filled HDPE nanocomposites in high-end offshore applications

Experiencing space–time: the stretched lifeworlds of migrant workers in India

In the relatively rare instances when the spatialities of temporary migrant work, workers’ journeys, and labour-market negotiations have been the subject of scholarly attention, there has been little work that integrates time into the analysis. Building on a case study of low-paid and insecure migrant manual workers in the context of rapid economic growth in India, we examine both material and subjective dimensions of these workers’ spatiotemporal experiences. What does it mean to live life stretched out, multiplyattached to places across national space? What kinds of place attachments emerge for people temporarily sojourning in, rather than moving to, new places to reside and work? Our analysis of the spatiotemporalities of migrant workers’ experiences in India suggests that, over time, this group of workers use their own agency to seek to avoid the experience of humiliation and indignity in employment relations. Like David Harvey, we argue that money needs to be integrated into such analysis, along with space and time. The paper sheds light on processes of exclusion, inequality and diff erentiation, unequal power geometries, and social topographies that contrast with neoliberalist narratives of ‘Indian shining

Novel Carbyne Filled Carbon Nanotube – Polymer Nanocomposites

The availability of carbyne in carbon nanotubes (CNTs) induces intrinsic stiffening and strengthening of CNTs, and is exploited for the very first time in this report to process epoxy nanocomposites with improved mechanical and electrical properties. The existence of encapsulated carbyne in double wall CNTs (DWNTs) was confirmed using High Resolution Transmission Electron Microscopy (HR-TEM). The intrinsic stiffening of carbyne reinforced DWNTs (c-DWNTs) in epoxy matrix was visually confirmed by Field Emission Scanning Electron Microscopy (FE-SEM). In comparison to raw DWNTs reinforced epoxy nanocomposites, c-DWNTS imparted modest but improved tensile strength (5.6%), elastic modulus (9.7%), failure strain (9.9%) and fracture toughness (13%) to their respective epoxy nanocomposites. This inaugural study on carbyne-filled polymer composites also reports a minor but distinct increase (an order of magnitude) in the electrical conductivity for c-DWNTs filled epoxy nanocomposites compared to DWNT filled epoxy nanocomposites

Oštećenja u aluminiju proizvedena zračenjem iz CO2 i Nd:YAG lasera

The change in the electrical properties of pure aluminium (Al 99.999%) after exposure to CO2 (energy = 2.5 J/pulse, wavelength = 10.6 µm, pulse duration = 200 nsec) and Nd:YAG (energy = 10 mJ/pulse, wavelength = 1.06 µm and pulse duration = 12 nsec) laser radiation is investigated. The samples were exposed to laser radiations for different numbers of pulses. The change in electrical characteristics of Al is studied under different ambient conditions, after irradiating the samples in air, vacuum and hydrogen at different pressures. After exposure, the electrical conductivity of Al is measured by the four probe method. The electrical conductivity decreases with increasing number of pulses. The damage in air and in hydrogen is more pronounced than in vacuum which can be attributed to collisionnal sputtering of Al by plasma ions of air molecules and hydrogen, respectively. The change in the conductivity in hydrogen is pressure-dependent. Some theoretical considerations are also made, e.g. the phonon speed in Al during the photon interaction, minimal melting and evaporation energy per volume, damage threshold energy, penetration depth, the mass of heated volume and average temperature rise at the Al surface during laser irradiation.Proučavamo promjene električnih svojstava čistog aluminija (Al 99.999%) nakon obasjavanja CO2 (energija = 2.5 J/puls, valna duljina = 10.6 µm, trajanje pulsa = 200 nsec) i Nd:YAG (energija = 10 mJ/puls, valna duljina = 1.06 µm, trajanje pulsa = 12 nsec) laserima. Uzorci su izloženi različitim brojevima pulseva. Proučavali smo promjene električne vodljivosti Al s uzorcima u zraku, vakuumu i u vodiku. Nakon obasjavanja mjerili smo električnu vodljivost metodom četiriju spojišta. Električna se vodljivost smanjuje nakon povećanog broja pulseva. Oštećenja u zraku i vodiku veća su nego u vakuumu, što se pripisuje sudarnom rasprašivanju Al ionima molekula zraka odnosno vodika u plazmi. Promjena vodljivosti uzoraka obasjanih u vodiku ovisna je o tlaku. Razmotrili smo neke teorijske rezultate, npr. fononsku brzinu u Al tijekom obasjavanja, minimalnu energiju taljenja i isparavanja po jedinici volumena, energijski prag oštećenja, dubinu prodiranja, masu zagrijanog volumena i prosječno povećanje temperature površine Al tijekom obasjavanja

Oštećenja u aluminiju proizvedena zračenjem iz CO2 i Nd:YAG lasera

The change in the electrical properties of pure aluminium (Al 99.999%) after exposure to CO2 (energy = 2.5 J/pulse, wavelength = 10.6 µm, pulse duration = 200 nsec) and Nd:YAG (energy = 10 mJ/pulse, wavelength = 1.06 µm and pulse duration = 12 nsec) laser radiation is investigated. The samples were exposed to laser radiations for different numbers of pulses. The change in electrical characteristics of Al is studied under different ambient conditions, after irradiating the samples in air, vacuum and hydrogen at different pressures. After exposure, the electrical conductivity of Al is measured by the four probe method. The electrical conductivity decreases with increasing number of pulses. The damage in air and in hydrogen is more pronounced than in vacuum which can be attributed to collisionnal sputtering of Al by plasma ions of air molecules and hydrogen, respectively. The change in the conductivity in hydrogen is pressure-dependent. Some theoretical considerations are also made, e.g. the phonon speed in Al during the photon interaction, minimal melting and evaporation energy per volume, damage threshold energy, penetration depth, the mass of heated volume and average temperature rise at the Al surface during laser irradiation.Proučavamo promjene električnih svojstava čistog aluminija (Al 99.999%) nakon obasjavanja CO2 (energija = 2.5 J/puls, valna duljina = 10.6 µm, trajanje pulsa = 200 nsec) i Nd:YAG (energija = 10 mJ/puls, valna duljina = 1.06 µm, trajanje pulsa = 12 nsec) laserima. Uzorci su izloženi različitim brojevima pulseva. Proučavali smo promjene električne vodljivosti Al s uzorcima u zraku, vakuumu i u vodiku. Nakon obasjavanja mjerili smo električnu vodljivost metodom četiriju spojišta. Električna se vodljivost smanjuje nakon povećanog broja pulseva. Oštećenja u zraku i vodiku veća su nego u vakuumu, što se pripisuje sudarnom rasprašivanju Al ionima molekula zraka odnosno vodika u plazmi. Promjena vodljivosti uzoraka obasjanih u vodiku ovisna je o tlaku. Razmotrili smo neke teorijske rezultate, npr. fononsku brzinu u Al tijekom obasjavanja, minimalnu energiju taljenja i isparavanja po jedinici volumena, energijski prag oštećenja, dubinu prodiranja, masu zagrijanog volumena i prosječno povećanje temperature površine Al tijekom obasjavanja