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Sorption of ammonium and nitrate to biochars is electrostatic and pH-dependent
Biochars are potentially effective sorbents for NH
4
+
and NO
3
−
in water treatment and soil applications. Here we compare NH
4
+
and NO
3
−
sorption rates to acid-washed biochars produced from red oak (
Quercus rubra
) and corn stover (
Zea mays
) at three pyrolysis temperatures (400, 500 and 600 °C) and a range of solution pHs (3.5–7.5). Additionally, we examined sorption mechanisms by quantification of NH
4
+
and NO
3
−
sorption, as well as Ca
2+
and Cl
−
displacement for corn stover biochars. Solution pH curves showed that NH
4
+
sorption was maximized (0.7–0.8 mg N g
−1
) with low pyrolysis temperature (400 °C) biochar at near neutral pH (7.0–7.5), whereas NO
3
−
sorption was maximized (1.4–1.5 mg N g
−1
) with high pyrolysis temperatures (600 °C) and low pH (3.5–4). The Langmuir (r
2
= 0.90–1.00) and Freundlich (r
2
= 0.81–0.97) models were good predictors for both NH
4
+
(pH 7) and NO
3
−
(pH 3.7) sorption isotherms. Lastly, NH
4
+
and NO
3
−
displaced Ca
2+
and Cl
−
, respectively, from previously CaCl
2
-saturated corn stover biochars. Results from the pH curves, Langmuir isotherms, and cation displacement curves all support the predominance of ion exchange mechanisms. Our results demonstrate the importance of solution pH and chemical composition in influencing NH
4
+
and NO
3
−
sorption capacities of biochar.
Journal Article
The promise : love and loss in modern China
At the start of the twentieth century in China, the Hans were married in an elaborate ceremony before they were even born. While their future was arranged by their families, this couple had much to be grateful for. Not only did they come from similar backgrounds - and as such were recognized as a good match - they also had a shared passion in their deep love of ancient Chinese poetry. They went on to have nine children and chose colours portrayed in some of their favourite poems as nicknames for them - Red, Cyan, Orange, Yellow, Green, Ginger, Violet, Blue and Rainbow. Fate, and the sweep of twentieth century history would later divide these children into three groups: three went to America or Hong Kong to protect the family line from the communists; three were married to revolutionaries having come of age as China turned red; while three suffered tragic early deaths. With her trademark wisdom and warmth, Xinran describes the lives and loves of this extraordinary family over four generations. What emerges is not only a moving, beautifully-written and engaging story of four people and their lives, but a crucial portrait of social change in China. Xinran begins with the magic and tragedy of one young couples wedding night in 1950, and goes on to tell personal experiences of loss, grief and hardship through China's extraordinary century. In doing so she tells a bigger story - how traditional Chinese values have been slowly eroded by the tide of modernity and how their outlooks on love, and the choices they've made in life, have been all been affected by the great upheavals of Chinese history. A spell-binding and magical narrative, this is the story of modern China through the people who lived through it, and the story of their love and loss.
Book
Structural transitions in influenza haemagglutinin at membrane fusion pH
Infection by enveloped viruses involves fusion of their lipid envelopes with cellular membranes to release the viral genome into cells. For HIV, Ebola, influenza and numerous other viruses, envelope glycoproteins bind the infecting virion to cell-surface receptors and mediate membrane fusion. In the case of influenza, the receptor-binding glycoprotein is the haemagglutinin (HA), and following receptor-mediated uptake of the bound virus by endocytosis
1
, it is the HA that mediates fusion of the virus envelope with the membrane of the endosome
2
. Each subunit of the trimeric HA consists of two disulfide-linked polypeptides, HA1 and HA2. The larger, virus-membrane-distal, HA1 mediates receptor binding; the smaller, membrane-proximal, HA2 anchors HA in the envelope and contains the fusion peptide, a region that is directly involved in membrane interaction
3
. The low pH of endosomes activates fusion by facilitating irreversible conformational changes in the glycoprotein. The structures of the initial HA at neutral pH and the final HA at fusion pH have been investigated by electron microscopy
4
,
5
and X-ray crystallography
6
–
8
. Here, to further study the process of fusion, we incubate HA for different times at pH 5.0 and directly image structural changes using single-particle cryo-electron microscopy. We describe three distinct, previously undescribed forms of HA, most notably a 150 Å-long triple-helical coil of HA2, which may bridge between the viral and endosomal membranes. Comparison of these structures reveals concerted conformational rearrangements through which the HA mediates membrane fusion.
Cryo-electron microscopy studies of the influenza haemagglutinin glycoprotein at the low pH of host endosomes reveals structural intermediates, offering a dynamic view of how the protein mediates membrane fusion.
Journal Article
Phase-change heterostructure enables ultralow noise and drift for memory operation
Artificial intelligence and other data-intensive applications have escalated the demand for data storage and processing. New computing devices, such as phase-change random access memory (PCRAM)–based neuro-inspired devices, are promising options for breaking the von Neumann barrier by unifying storage with computing in memory cells. However, current PCRAM devices have considerable noise and drift in electrical resistance that erodes the precision and consistency of these devices. We designed a phase-change heterostructure (PCH) that consists of alternately stacked phase-change and confinement nanolayers to suppress the noise and drift, allowing reliable iterative RESET and cumulative SET operations for high-performance neuro-inspired computing. Our PCH architecture is amenable to industrial production as an intrinsic materials solution, without complex manufacturing procedure or much increased fabrication cost.
Journal Article
Loss-induced suppression and revival of lasing
Controlling and reversing the effects of loss are major challenges in optical systems. For lasers, losses need to be overcome by a sufficient amount of gain to reach the lasing threshold. In this work, we show how to turn losses into gain by steering the parameters of a system to the vicinity of an exceptional point (EP), which occurs when the eigenvalues and the corresponding eigenstates of a system coalesce. In our system of coupled microresonators, EPs are manifested as the loss-induced suppression and revival of lasing. Below a critical value, adding loss annihilates an existing Raman laser. Beyond this critical threshold, lasing recovers despite the increasing loss, in stark contrast to what would be expected from conventional laser theory. Our results exemplify the counterintuitive features of EPs and present an innovative method for reversing the effect of loss.
Journal Article
Purification of Contaminated Water Using Eco Enzyme
Eco Enzyme is an unpredictable arrangement formed by the fermentation of new kitchen squander, brown sugar and water. Utilization of Garbage Enzyme is developing as a viable strategy for treating contaminated water. The arrangement can be used after three months to purify the contaminated water. A message will be sent with the help of IoT once the solution is ready. Two different combinations of vegetable squanders are used and tested in the contaminated water. One solution gives better result when compared with the other solution. IoT is used to send message to the registered mobile once the solution reached required pH value. Furthermore improvements like sending message based on the application of the solution can be added in future.
Journal Article
Shapley value of n-person prisoner’s dilemma
n-Person prisoner’s dilemma is a Markovian sequence of static games that are realized randomly depending on players’ previous choices. The dynamic Shapley value is constructed in this case. The work is a continuation of the paper published earlier by Grinikh A. L. [1]. In this paper, we consider the new approach of dynamics of game which depends on the strategies of all players.
Journal Article
Mechanistic understanding of the adsorption and thermodynamic aspects of cationic methylene blue dye onto cellulosic olive stones biomass from wastewater
In the current study, the mechanistic understanding of the adsorption isotherm and thermodynamic aspects of cationic methylene blue (MB) dye adsorption onto cellulosic olive stones biomass from wastewater were investigated. The batch adsorption of MB onto the olive stones (black and green olive stones) was tested at a variety of pH, dye concentrations, temperatures, and biomass particle sizes. The adsorption thermodynamics such as Gibbs free energy, enthalpy, and entropy changes were also calculated. Moreover, the desorption studies of MB from the spent olive stones were studied to explore the re-usability of the biomasses. The results revealed that under the optimum pH of 10, the maximum MB uptake was achieved i.e. 80.2% for the green olive stones and 70.9% for the black olive stones. The green olive stones were found to be more efficient in remediating higher MB concentrations from water than the black olive stones. The highest MB removal of the green olive stones was achieved at 600 ppm of MB, while the highest MB removal of the black olive stones was observed at 50 ppm of MB. Furthermore, for almost all the concentrations studied (50–1000 ppm), the MB adsorption was the highest at the temperature of 45 °C (
P
value < 0.05). It was shown by the Fourier transform infrared that the electrostatic interaction and hydrogen bonding were proposed as dominant adsorption mechanisms at basic and acidic pH, respectively. While the hydrophobic-hydrophobic interaction was a dominant mechanism at neutral pH. The thermodynamic studies revealed that the adsorption process was endothermic, spontaneous, and favorable. Moreover, the real wastewater experiment and the desorption studies showed that the green and black olive stones were a cost-effective and promising adsorbents for MB remediation from wastewater on account of their high adsorption and desorption removal capacities.
Journal Article
Co-designing electronics with microfluidics for more sustainable cooling
Thermal management is one of the main challenges for the future of electronics
1
–
5
. With the ever-increasing rate of data generation and communication, as well as the constant push to reduce the size and costs of industrial converter systems, the power density of electronics has risen
6
. Consequently, cooling, with its enormous energy and water consumption, has an increasingly large environmental impact
7
,
8
, and new technologies are needed to extract the heat in a more sustainable way—that is, requiring less water and energy
9
. Embedding liquid cooling directly inside the chip is a promising approach for more efficient thermal management
5
,
10
,
11
. However, even in state-of-the-art approaches, the electronics and cooling are treated separately, leaving the full energy-saving potential of embedded cooling untapped. Here we show that by co-designing microfluidics and electronics within the same semiconductor substrate we can produce a monolithically integrated manifold microchannel cooling structure with efficiency beyond what is currently available. Our results show that heat fluxes exceeding 1.7 kilowatts per square centimetre can be extracted using only 0.57 watts per square centimetre of pumping power. We observed an unprecedented coefficient of performance (exceeding 10,000) for single-phase water-cooling of heat fluxes exceeding 1 kilowatt per square centimetre, corresponding to a 50-fold increase compared to straight microchannels, as well as a very high average Nusselt number of 16. The proposed cooling technology should enable further miniaturization of electronics, potentially extending Moore’s law and greatly reducing the energy consumption in cooling of electronics. Furthermore, by removing the need for large external heat sinks, this approach should enable the realization of very compact power converters integrated on a single chip.
Cooling efficiency is greatly increased by directly embedding liquid cooling into electronic chips, using microfluidics-based heat sinks that are designed in conjunction with the electronics within the same semiconductor substrate.
Journal Article