Atmospheric water vapor condensation on engineered interfaces: Busting the myths

Condensing atmospheric water vapor on surfaces is a sustainable approach to potentially address the potable water crisis. However, despite extensive research, a key question remains: what is the physical mechanism governing the condensation from humid air and how significantly does it differ from pure steam condensation? The answer may help define an optimal combination of the mode and mechanism of condensation as well as the surface wettability for best possible water harvesting efficacy. Here we show that this lack of clarity is due to the differences in heat transfer characteristics during condensation from pure vapor and humid air environments. Specifically, during condensation from humid air, the thermal resistance across the condensate is non-dominant and the energy transfer is controlled by vapor diffusion and condensate drainage. This leads to filmwise condensation on superhydrophilic surfaces, offering the highest water collection efficiency. To demonstrate this, we measured condensation rate on different sets of superhydrophilic and superhydrophobic surfaces in a wide degree of subcooling (10 - 26 C) and humidity-ratio differences (5 - 45 g/kg of dry air). The resulting condensation rate is enhanced by 57 - 333 % on the superhydrophilic surfaces as compared to the superhydrophobic ones. The findings of this study challenges the nearly century-old scientific ambiguity about the mechanism of vapor condensation from humid air. Our findings will lead to the design of efficient atmospheric water harvesting systems

Preferred Mode of Atmospheric Water Vapor Condensation on Nanoengineered Surfaces: Dropwise or Filmwise?

Condensing atmospheric water vapor on surfaces is a sustainable approach to addressing the potable water crisis. However, despite extensive research, a key question remains: what is the optimal combination of the mode and mechanism of condensation as well as the surface wettability for the best possible water harvesting efficacy? Here, we show how various modes of condensation fare differently in a humid air environment. During condensation from humid air, it is important to note that the thermal resistance across the condensate is nondominant, and the energy transfer is controlled by vapor diffusion across the boundary layer and condensate drainage from the condenser surface. This implies that, unlike condensation from pure steam, filmwise condensation from humid air would exhibit the highest water collection efficiency on superhydrophilic surfaces. To demonstrate this, we measured the condensation rates on different sets of superhydrophilic and superhydrophobic surfaces that were cooled below the dew points using a Peltier cooler. Experiments were performed over a wide range of degrees of subcooling (10–26 °C) and humidity-ratio differences (5–45 g/kg of dry air). Depending upon the thermodynamic parameters, the condensation rate is found to be 57–333% higher on the superhydrophilic surfaces compared to the superhydrophobic ones. The findings of the study dispel ambiguity about the preferred mode of vapor condensation from humid air on wettability-engineered surfaces and lead to the design of efficient atmospheric water harvesting systems

Coral record of Younger Dryas Chronozone warmth on the Great Barrier Reef

Author Posting. © American Geophysical Union, 2020. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography and Paleoclimatology 35(12), (2020): e2020PA003962, doi:10.1029/2020PA003962.The Great Barrier Reef (GBR) is an internationally recognized and widely studied ecosystem, yet little is known about its sea surface temperature (SST) evolution since the Last Glacial Maximum (LGM) (~20 kyr BP). Here, we present the first paleo‐application of Isopora coral‐derived SST calibrations to a suite of 25 previously published fossil Isopora from the central GBR spanning ~25–11 kyr BP. The resultant multicoral Sr/Ca‐ and δ18O‐derived SST anomaly (SSTA) histories are placed within the context of published relative sea level, reef sequence, and coralgal reef assemblage evolution. Our new calculations indicate SSTs were cooler on average by ~5–5.5°C at Noggin Pass (~17°S) and ~7–8°C at Hydrographer's Passage (~20°S) (Sr/Ca‐derived) during the LGM, in line with previous estimates (Felis et al., 2014, https://doi.org/10.1038/ncomms5102). We focus on contextualizing the Younger Dryas Chronozone (YDC, ~12.9–11.7 kyr BP), whose Southern Hemisphere expression, in particular in Australia, is elusive and poorly constrained. Our record does not indicate cooling during the YDC with near‐modern temperatures reached during this interval on the GBR, supporting an asymmetric hemispheric presentation of this climate event. Building on a previous study (Felis et al., 2014, https://doi.org10.1038/ncomms5102), these fossil Isopora SSTA data from the GBR provide new insights into the deglacial reef response, with near‐modern warming during the YDC, since the LGM.This work was funded by National Science Foundation (NSF) award OCE 13‐56948 to B. K. L, with NSF GRFP support DGE‐11‐44155 to L. D. B., and the Australian Research Council (grant no. DP1094001) and ANZIC IODP. Partial support for B. K. L's work on this project also came from the Vetlesen Foundation via a gift to the Lamont‐Doherty Earth Observatory. T. F. received funding from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)—Project number 180346848, through Priority Program 527 “IODP.” A. T. received support from the UK Natural Environment Research Council (NE/H014136/1 and NE/H014268/1). M. T. thanks Ministry of Earth Sciences for support (NCPOR contribution no. J‐84/2020‐21). L. D. B. would also like to thank Kassandra Costa for her input regarding error analysis.2021-06-1

Metaphors in Nanomedicine: The Case of Targeted Drug Delivery

International audienceThe promises of nanotechnology have been framed by a variety of metaphors, that not only channel the attention of the public, orient the questions asked by researchers, and convey epistemic choices closely linked to ethical preferences. In particular, the image of the 'therapeutic missile' commonly used to present targeted drug delivery devices emphasizes precision, control, surveillance and efficiency. Such values are highly praised in the current context of crisis of pharmaceutical innovation where military metaphors foster a general mobilization of resources from multiple fields of cutting-edge research. The missile metaphor, reminiscent of Paul Ehrlich's 'magic bullet', has framed the problem in simple terms: how to deliver the right dose in the right place at the right moment? Chemists, physicists and engineers who design multi-functional devices operating in vitro can think in such terms, as long as the devices are not actually operating through the messy environment of the body. A close look at what has been done and what remains to be done suggests that the metaphor of the "therapeutic missile" is neither sufficient, nor even necessary. Recent developments in nanomedicine suggest that therapeutic efficacy cannot be obtained without negotiating with the biological milieu and taking advantage of what it affords. An 'oïkological' approach seems more appropriate, more heuristic and more promising than the popular missile. It is based on the view of organism as an oikos that has to be carefully managed. The dispositions of nanocapsules have to be coupled with the affordances of the environment. As it requires dealing with nanoparticles as relational entities (defined by their potential for interactions) rather than as stable substances (defined by intrinsic properties) this metaphor eventually might well change research priorities in nanotechnology in general

Genomics-assisted breeding in four major pulse crops of developing countries: present status and prospects

The global population is continuously increasing and is expected to reach nine billion by 2050. This huge population pressure will lead to severe shortage of food, natural resources and arable land. Such an alarming situation is most likely to arise in developing countries due to increase in the proportion of people suffering from protein and micronutrient malnutrition. Pulses being a primary and affordable source of proteins and minerals play a key role in alleviating the protein calorie malnutrition, micronutrient deficiencies and other undernourishment-related issues. Additionally, pulses are a vital source of livelihood generation for millions of resource-poor farmers practising agriculture in the semi-arid and sub-tropical regions. Limited success achieved through conventional breeding so far in most of the pulse crops will not be enough to feed the ever increasing population. In this context, genomics-assisted breeding (GAB) holds promise in enhancing the genetic gains. Though pulses have long been considered as orphan crops, recent advances in the area of pulse genomics are noteworthy, e.g. discovery of genome-wide genetic markers, high-throughput genotyping and sequencing platforms, high-density genetic linkage/QTL maps and, more importantly, the availability of whole-genome sequence. With genome sequence in hand, there is a great scope to apply genome-wide methods for trait mapping using association studies and to choose desirable genotypes via genomic selection. It is anticipated that GAB will speed up the progress of genetic improvement of pulses, leading to the rapid development of cultivars with higher yield, enhanced stress tolerance and wider adaptability

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Not AvailableThis paper focuses on review of development of proven designs for threshing of cereals, oilseeds, pulses for savings of labour, time and cost of operations. The development of power threshers started in India in mid 1950's.The use of mechanical power for threshing started with the use of chaff cutters in Punjab. It was used to chop up the wheat crop, which also partially threshed the heads. Mechanical threshers of varying power range (3.7-15 kW) are commercially being manufactured which not only thresh the grain but also provide good quality bhusa for cattle feed. It is estimated that there are nearly 30 million threshers of various designs in operation in the country. The annual addition to this number is 2,00,000 units. Multi-crop threshers in 3.7 kW capacity have been developed at CIAE, Bhopal, ANGRAU Hyderabad and PAU Ludhiana centres of AICRP on FIM and these have been commercialized through industrial liaisoning. These designs proved successful in reducing total losses, power consumption, straw/stalk size, human drudgery ensuring quality produce. The main parameters which affected the performance of the threshers, were speed of the threshing cylinder, feed rate and moisture content of the harvested crop. The intensity of the impact of the pegs of the cylinder on the crop was dependent on the rotating speed of threshing cylinder which affected the threshing efficiency, grain damage and power requirement. For higher threshing efficiency, fine straw quality and minimum specific power consumption, rectangular spiked threshing cylinder of 600 mm tip diameter and spike thickness of 6 mm have given best performance results with total grain loss within permissible limit. The spike thickness of 6 mm gave minimum broken grain loss with fine straw quality. The round spiked (plain spike) threshing cylinder with same configuration of threshing cylinder showed best results. But from mass manufacturing point of view, tip diameter of 600 mm and 8 mm round spike thickness will be appropriate for manufacturers. It also delivered good output capacity and threshing efficiency and fine straw quality.Not Availabl

Clinical and Microbiological Profile of Urinary Tract Infection in Children Less Than Twelve Years of the Age and Their Antibiotics Resistant Pattern at A Tertiary Care Hospital in Kanpur, India

Background: Urinary tract infection (UTI) is the most common bacterial infection which is seen in childhood population, which starts from the calyces of the kidney to the urethra. It is an important cause of morbidity and mortality in children mostly in the first 2 years of life. The Gram negative enteric bacilli, especially Escherichia coli and Klebsiella spp. the dominant pathogens. The objective of the study was to analyze the causative microorganism and their Antibiotic Resistance Pattern in UTI in childhood population between 0-12years of the age. Methods: This one year prospective and observational study was conducted in the Department of Microbiology; Rama Medical College Hospital & Research Centre Kanpur, Uttar Pradesh, India, on 100 pediatric patients (aged 0-12 years). All the pediatric age group (0-12 years) with suspected UTI and, whose urine culture showed one or two pathogen with colony counts greater than or equal to 105 colony forming units (CFU)/ml was included for the study. Clinical data was obtained from OPD and IPD Patients. Antimicrobial susceptibility was done for positive urine culture by Kirby-Bauer disk diffusion method. The data was expressed in terms of frequency and percentage

Elevational plant species richness patterns and their drivers across non-endemics, endemics and growth forms in the Eastern Himalaya

Despite decades of research, ecologists continue to debate how spatial patterns of species richness arise across elevational gradients on the Earth. The equivocal results of these studies could emanate from variations in study design, sampling effort and data analysis. In this study, we demonstrate that the richness patterns of 2,781 (2,197 non-endemic and 584 endemic) angiosperm species along an elevational gradient of 300-5,300 m in the Eastern Himalaya are hump-shaped, spatial scale of extent (the proportion of elevational gradient studied) dependent and growth form specific. Endemics peaked at higher elevations than non-endemics across all growth forms (trees, shrubs, climbers, and herbs). Richness patterns were influenced by the proportional representation of the largest physiognomic group (herbs). We show that with increasing spatial scale of extent, the richness patterns change from a monotonic to a hump-shaped pattern and richness maxima shift toward higher elevations across all growth forms. Our investigations revealed that the combination of ambient energy (air temperature, solar radiation, and potential evapo-transpiration) and water availability (soil water content and precipitation) were the main drivers of elevational plant species richness patterns in the Himalaya. This study highlights the importance of factoring in endemism, growth forms, and spatial scale when investigating elevational gradients of plant species distributions and advances our understanding of how macroecological patterns arise.Kumar Manish, Maharaj K. Pandit, Yasmeen Telwala, Dinesh C. Nautiyal, Lian Pin Koh, Sudha Tiwar

Surface Tension Confined (STC) Tracks for Capillary-Driven Transport of Low Surface Tension Liquids

Surface tension confined (STC) open tracks for pumpless transport of low-surface tension liquids (e.g., acetone, ethanol, hexadecane) on microfluidic chips are fabricated using a large-area, wet-processing technique. Wettable, paraffin-wax, submillimeter-wide tracks are applied by a fountain-pen procedure on superoleophobic, fluoroacrylic-carbon nanofiber (CNF) composite coatings. The fabricated anisotropic wetting patterns confine the low-surface-tension liquids onto the flow tracks, driving them with meniscus velocities up to 3.1 cm s(-1). Scaling arguments and Washburn's equation provide estimates of the liquid velocities measured in the STC tracks. These tracks are also shown to act as rails for directional sliding control of mm-sized water droplets. The present facile top-down patterned wettability approach can be extended to deposit micrometer-wide tracks, which bear promise for pumpless handling of low-surface tension liquids (e.g., aqueous solutions containing alcohols or surfactants) in lab-on-a-chip type applications or in low power, high-throughput bio-microfluidics for health care applications