A LED-based Functional Light Source for the Characterization of Thin Film Solar Cells

A light source of selective functionalities of wavelengths, illumination periods, and intensities is desirable for investigating performance parameters as well as the quality of different layers and interfaces of solar cells. Conventional light sources used for these types of research are expensive, space-consuming, cumbersome to work with, and have limited functionalities. We have developed a light source with variable wavelength, intensity, and illumination period to address these issues using an illumination period control unit, voltage regulator, neutral density filter, alterable light emitting diodes, etc. As a proof-of-concept, we employed our constructed light source to investigate the intensity, wavelength, illumination period modulated photovoltaic, and impedance properties of inorganic thin film solar cells such as cadmium telluride (CdTe) and copper zinc tin sulfide (CZTS) using lights of wavelength 410, 520, and 635 nm. We hope to use this light source for photophysical and photochemical studies of metal oxide materials used for renewable energy research.Comment: 4 pages, 7 figure

Sustainability through the Lens of Environmental Sociology

Our planet is undergoing radical environmental and social changes. Sustainability has now been put into question by, for example, our consumption patterns, loss of biodiversity, depletion of resources, and exploitative power relations. With apparent ecological and social limits to globalization and development, current levels of consumption are unsustainable, inequitable, and inaccessible to the majority of humans. Understanding and attaining sustainability is a crucial matter at a time when our planet is in peril—environmentally, economically, socially, and politically. Since its official inception in the 1970s, environmental sociology has provided a powerful lens to understanding the challenges, possibilities and modes of sustainability. Most chapters in this book were published as peer-reviewed articles in Sustainability in its special issue “Sustainability through the Lens of Environmental Sociology”, providing an environmental sociology approach to understanding and achieving the widely used notion of “sustainability.” This edited collection covers, among other topics, the inherent discursive formations of environmental sociology, conceptual tools and paradoxes, competing theories and practices, and their complex implications on our society at large. Chapters in this book specifically focus on how sustainable development has been understood through different theoretical lenses in environmental sociology, such as ecological modernization, policy/reformist sustainable development, and critical structural approaches (such as the treadmill of production, ecological Marxism, metabolic rift theory, etc.); and how sustainable development has been practiced in, or by, various stakeholders, such as states, corporations, and local communities, for various ends, through the use of specific case studies, showing, for example, the discursive shifts, dynamic formations, and diverse contours of sustainable development. The range of relevant topics includes: • Environmental sociology as a field of inquiry for sustainability • Historical context of sustainable development in environmental sociology • Nature-society relationship in environmental sociology • Theories/approaches to sustainability discourse in environmental sociology • Environmentalism/environmental movements for sustainability • Empirical cases (such as climate change, biodiversity, food, certification, etc.) through the lens of environmental sociolog

The Extend of Criminal Responsibilities of a Superior for the Commission of Offences by the Subordinates

The superior is responsible for atrocities committed by the subordinates violating International Humanitarian Law is not a new concept in the legal arena but it was applied even in the ancient time among the leaders of the tribe. Although the doctrine of superior responsibility was applied in many cases before and after the Second and First World War but it was first codified in articles 86&86 of the Additional Protocol 1 of the Geneva Conventions 1949. Now, it is established by many international instruments i.e.Statute of International Criminal Tribunal for Former Yugoslavia. and case laws that the superior is liable for committing international crimes i.e. crimes against humanity, war crime and genocide, by the subordinates but from beginning to today a debate is continuing  either the superior is responsible for the offences committed by the subordinates or for a separate offence committed by superior through omission to discharge his duty to prevent, control and punish the subordinates for violating war laws. In This paper intends to establish that the superior is not responsible for the offences committed by the subordinates as a mode of liability or as an accomplice but he/she is liable for separate offence for his/her failure to prevent and suppress the subordinates. Secondly the authors want to clear that superior and principal offender is not the same person but if a superior by orders, abets, instigates in any other modes participate in the commission of the offences then the superior is responsible for the offences committed by the subordinates. Key words: Superior responsibility, command responsibility, responsibility, subordinates. International Humanitarian La

Sociological perspectives on climate change and society: A review

Ministry of Education, Singapore under its Academic Research Funding Tier

Pressure-driven Flow Instability with Convective Heat Transfer Through a Curved Rectangular Duct of Small Aspect Ratio

AbstractThe present study investigates unsteady fluid flow through a curved rectangular duct of aspect ratio 0.5 and curvature 0.5. Numerical calculations are carried out by using a spectral method, and covering a wide range of the pressure gradient parameter, the Dean number, 6000 ≤ Dn ≤ 12000 and the Grashof number, 100 ≤ Gr ≤ 2000 for two cases of the duct, Case-I: Stationary duct and Case-II: Rotating duct. The outer wall of the duct is heated while the inner wall cooled. The main concern of the present study is to discuss the unsteady flow behavior i.e whether the unsteady flow is steady-state, periodic, multi-periodic or chaotic, if Dn or Gr is increased. For a stationary duct, we investigate the unsteady flow characteristics for the Dean number 6000 ≤ Dn ≤ 12000 and the Grashof number 100 ≤ Gr ≤ 2000, and it is found that the unsteady flow undergoes in the scenario steady-state → periodic → multi-periodic → chaotic, if Gr is increased. For rotating duct, however, we investigate the unsteady flow characteristics for the Taylor number −100 Tr ≤ 1000, and it is found that the unsteady flow undergoes through various flow instabilities, if Dn or Gr is increased. Typical contours of secondary flow patterns and temperature profiles are also obtained, and it is found that the unsteady flow consists of a single-, two-, and multi-vortex solutions

Spectral Numerical Calculation of Non-isothermal Flow through a Rotating Curved Rectangular Duct with Moderate Curvature

The present paper investigates non-isothermal flow characteristics through a rotating curved rectangular duct, where co-existence of the rotational forces and fluid temperature gradients leads to the emergence of rotation-induced buoyancy effects. A spectral-based numerical scheme is employed as the principal tool for the simulation while Chebyshev polynomial and collocation method as the secondary tools. The outer wall of the duct is heated while the inner wall cooled, the top and bottom walls being thermally insulated. The emerging parameters controlling the flow characteristics are the rotation parameter, i.e., the Taylor number Tr ranging 0 to 2000, the Grashof number Gr = 100, the Prandtl number Pr, the aspect ratio, and the pressure-driven parameter, i.e., the Dean number Dn between 100 and 1000. The flow structures are examined under combined action of the centrifugal, Coriolis and buoyancy forces. As a result, asymmetric 2-cell structures are computed for small values of Tr while asymmetric 6-cell structures for large Tr. Unsteady flow characteristics show that the flow undergoes in the scenario ‘chaotic→ multi-periodic → periodic→ steady-state’, if Tr is increased in the positive direction. Typical contours of secondary flow patterns, temperature profiles and axial flow distribution are also obtained at several values of Tr, and it is found that there exist asymmetric two- to multi-vortex solutions. Heating the outer wall is found to generate a significant temperature gradient at the outer concave wall

Prebiotic selection and assembly of proteinogenic amino acids and natural nucleotides from complex mixtures

A central problem for the prebiotic synthesis of biological amino acids and nucleotides is to avoid the concomitant synthesis of undesired or irrelevant by-products. Additionally, multistep pathways require mechanisms that enable the sequential addition of reactants and purification of intermediates that are consistent with reasonable geochemical scenarios. Here, we show that 2-aminothiazole reacts selectively with two- and three-carbon sugars (glycolaldehyde and glyceraldehyde, respectively), which results in their accumulation and purification as stable crystalline aminals. This permits ribonucleotide synthesis, even from complex sugar mixtures. Remarkably, aminal formation also overcomes the thermodynamically favoured isomerization of glyceraldehyde into dihydroxyacetone because only the aminal of glyceraldehyde separates from the equilibrating mixture. Finally, we show that aminal formation provides a novel pathway to amino acids that avoids the synthesis of the non-proteinogenic α,α-disubstituted analogues. The common physicochemical mechanism that controls the proteinogenic amino acid and ribonucleotide assembly from prebiotic mixtures suggests that these essential classes of metabolite had a unified chemical origin

Effect of Substrate Surface on the Wide Bandgap SnO2 Thin Films Grown by Spin Coating

Tin (IV) oxide (SnO2) sols have been synthesized from SnCl2.2H2O precursor solution by applying two different processing conditions. The prepared sols were then deposited on UV-Ozone treated quartz and soda lime glass (SLG) substrates by spin coating. The as-synthesized film was soft-baked at about 100 deg. C. for 10 min. This process was repeated five times to get a compact film, followed by air-annealing at 250 deg. C. for 2 h. The pristine and annealed films were characterized by UV-Vis-NIR spectroscopy, Grazing Incident X-Ray Diffraction (GIXRD), and Field Emission Scanning Electron Microscope (FESEM). The effect of substrate surface was investigated by measuring the contact angles with De-Ionized (DI) water. UV-Ozone treatment of substrate provides a cleaner surface to grow a homogeneous film. The electrical resistivity of annealed thin films was carried out by a four-point-collinear probe employing the current reversal technique and found in the range of approx. 2x10^3 to 3x10^3 Ohm.cm. Film thickness was found in the range of approx. 137-285 nm, measured by a stylus profilometer. UV-Vis-NIR Transmission data revealed that all the thin film samples showed maximum (82-89) % transmission in the visible range. The optical bandgap of the thin films was estimated to be approx. 3.75 to 4.00 eV and approx. 3.78 to 4.35 eV for the films grown on SLG and quartz substrates, respectively.Comment: 4 pages, 7 figure

Air pollution emissions 2008–2018 from Australian coal mining: implications for public and occupational health

Occupational exposure limits for respirable coal dust are based on exposure during working hours, but coal miners may experience additional community-based exposures during nonworking hours. We analyzed Australia National Pollutant Inventory (NPI) data for the years 2008–2018 to estimate air pollutants (metals, nitrogen oxides, particulate matter ≤ 10 micrometers (PM10) and ≤ 2.5 micrometers (PM2.5)) originating from coal mines. PM10 levels from community-based air monitors in Queensland and New South Wales were also compared between mining and nonmining communities. Results indicated that tons of coal mined increased over the study period, and that levels of particulate matter, metals, and nitrogen oxides increased significantly over time as well. Coal mines accounted for 42.1% of national PM10 air emissions from NPI sites. PM2.5 from coal mines accounted for 19.5% of the national total, metals for 12.1%, and nitrogen oxides for 10.1%. Coal mining occurred in 57 different post codes; the 20 coal-mining post codes with the highest PM10 emissions were home to 160,037 people. Emissions of all studied pollutants were significantly higher from coal mining sites than from other types of NPI sites. Results from community-based air monitoring stations indicated significantly higher population PM10 exposure in coal mining communities than in nonmining communities. The health of the public at large is impacted by coal mining, but to the extent that miners also live near coal mining operations, their total exposure is underestimated by consideration of exposure only during working hours