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"A, Prakash"
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Origin of voltage decay in high-capacity layered oxide electrodes
Although Li-rich layered oxides (Li
1+
x
Ni
y
Co
z
Mn
1−
x
−
y
−
z
O
2
> 250 mAh g
−1
) are attractive electrode materials providing energy densities more than 15% higher than today’s commercial Li-ion cells, they suffer from voltage decay on cycling. To elucidate the origin of this phenomenon, we employ chemical substitution in structurally related Li
2
RuO
3
compounds. Li-rich layered Li
2
Ru
1−
y
Ti
y
O
3
phases with capacities of ~240 mAh g
−1
exhibit the characteristic voltage decay on cycling. A combination of transmission electron microscopy and X-ray photoelectron spectroscopy studies reveals that the migration of cations between metal layers and Li layers is an intrinsic feature of the charge–discharge process that increases the trapping of metal ions in interstitial tetrahedral sites. A correlation between these trapped ions and the voltage decay is established by expanding the study to both Li
2
Ru
1−
y
Sn
y
O
3
and Li
2
RuO
3
; the slowest decay occurs for the cations with the largest ionic radii. This effect is robust, and the finding provides insights into new chemistry to be explored for developing high-capacity layered electrodes that evade voltage decay.
Although Li-rich layered oxides are attractive electrode materials for batteries, they suffer from voltage decay on cycling. A correlation between trapped metal ions in interstitial tetrahedral sites and voltage decay is established, which could prove useful for developing high-capacity electrodes without decay.
Journal Article
Impressionism in Canada : a journey of rediscovery
Impressionist paintings are among the most prized artworks in the world, yet little has been written about Canadian impressionism. Now, with this book, we have a full account of the development of this revolutionary style in painting during the four decades after 1875, first in France, then in the United States, and finally in Canada.
Book
Starch-derived superabsorbent polymers in agriculture applications: an overview
At present, the growing environmental concerns have strengthened the use of biodegradable and natural polymers in the synthesis of superabsorbent polymer (SAP) particularly in agriculture applications as natural polymers are much more efficient and environmentally friendly than synthetic ones. Starch is the most abundant carbohydrate polymer, biodegradable, and a renewable raw resource, with good chemical stability and high reactivity. Thus, starch-based SAP has gained huge interest in the agriculture field in the past few years. This review presents the significance of SAP in agriculture, starch-derived SAP, crosslinking and graft copolymerization techniques used in the synthesis of starch-based SAP as well as control release formulations and control release study of agrochemicals. The review significantly elaborates the synthesis techniques and various chemistries used for the preparation of SAP as well as the structure–property relationships like the effect of grafting or doping on the swelling kinetics and water absorbency. Furthermore, the various mainstream characterization techniques also reviewed which are generally used for the analysis of SAP.
Journal Article
Responding to globalization
\"The new challenges and opportunities created by the spread of globalization have reshaped both institutional and individual responses to this phenomenon. This comprehensive analysis of the way in which governments and firms have responded to globalization examines closely the options available to both, and the historical and institutional contexts to the strategic decisions made.\" \"This rigorous survey focuses on political, ideational and economic factors lying behind these responses to globalization. It is essential reading for all those interested in globalization, international business and international political economy.\"--Jacket.
Book
A review on the micro-encapsulation of phase change materials: classification, study of synthesis technique and their applications
The requirement for energy and its management is growing in today's world. The energy sector is an area of interest for many countries around the world. To address the current fossil fuel issue, the scientific community is developing novel energy-saving experiments. Thermal energy storage is a mode of conserving energy. Thermal energy storage not only reduces energy consumption inconsistencies but also improves energy efficiency and reliability, which is an important part of energy conservation. In the realm of thermal energy storage, phase change materials (PCMs) are growing popularity and gaining awareness. By expanding, the area of heat transfer and reducing the seepage of melting materials, microcapsules improve the mechanical and thermal performance of PCMs used in the storage of thermal energy. PCM encapsulation is required to avoid PCM leakage, increase heat transmission, and control and reduce PCM reactivity with the environment. A vast number of researches on PCM microcapsules have been reported recently to explain their utility in energy systems. A complete evaluation of PCM microcapsules for thermal energy storage is presented in this paper. This review covers five topics: PCM classification, shell materials of encapsulation, microencapsulation methods, characterization of PCM microcapsules, and thermal applications. This review intends to aid researchers from diverse domains to gain a better understanding of PCM microcapsules and provide crucial guidance for future thermal energy storage using this technology.
Journal Article
Beyond oil and gas : the methanol economy
Examining the major challenges of future energy and environmental problems, this work discusses in a clear and accessible manner, the use of methanol as a viable alternative to dangerous and dwindling energy resources.
Book
Reversible anionic redox chemistry in high-capacity layered-oxide electrodes
Li-ion batteries have contributed to the commercial success of portable electronics and may soon dominate the electric transportation market provided that major scientific advances including new materials and concepts are developed. Classical positive electrodes for Li-ion technology operate mainly through an insertion–deinsertion redox process involving cationic species. However, this mechanism is insufficient to account for the high capacities exhibited by the new generation of Li-rich (Li
1+
x
Ni
y
Co
z
Mn
(1−
x
−
y
−
z
)
O
2
) layered oxides that present unusual Li reactivity. In an attempt to overcome both the inherent composition and the structural complexity of this class of oxides, we have designed structurally related Li
2
Ru
1−
y
Sn
y
O
3
materials that have a single redox cation and exhibit sustainable reversible capacities as high as 230 mA h g
−1
. Moreover, they present good cycling behaviour with no signs of voltage decay and a small irreversible capacity. We also unambiguously show, on the basis of an arsenal of characterization techniques, that the reactivity of these high-capacity materials towards Li entails cumulative cationic (M
n
+
→M
(
n
+1)+
) and anionic (O
2−
→O
2
2−
) reversible redox processes, owing to the
d
–
s
p
hybridization associated with a reductive coupling mechanism. Because Li
2
MO
3
is a large family of compounds, this study opens the door to the exploration of a vast number of high-capacity materials.
Cathodes for Li-ion batteries operate mainly via an insertion–deinsertion redox process involving cationic species but this mechanism does not account for the high capacities displayed by Li-rich layered oxides. The reactivity of high-capacity Li
2
Ru
1−
y
Sn
y
O
3
materials is now shown to be associated with a reversible redox process related to a reductive coupling mechanism.
Journal Article
Pulmonary function abnormality in patients recovered from Covid 19 pneumonia, in a tertiary care hospital in India
ABSTRACT
Background:
One of the most dreaded complications of COVID pneumonia is post-COVID residual lung fibrosis and lung function impairment.
Objectives:
To find out the extent and type of pulmonary function abnormality using spirometry, diffusion capacity, and 6-minute walk test and to co-relate with the clinical severity at the time of infection, in patients who have recovered from COVID19 pneumonia, in a tertiary care hospital in India.
Materials and Methods:
This is a prospective, cross-sectional study with a total 100 patients. Patients who have recovered from COVID pneumonia after one month of onset of symptoms and before 3 months who come for follow-up and have respiratory complaints undergo pulmonary function test will be recruited in the study.
Results:
In our study, the most common lung function abnormality detected was restrictive pattern in 55% of the patients (N = 55) followed by mixed pattern in 9% of patients (N = 9), obstructive in 5% of patients (N = 5), and normal in 31% of patients (N = 31). In our study, total lung capacity was reduced in 62% of the patients and normal in 38% of the patients and diffusion capacity of lung was reduced in 52% of the patients recovered from 52% of the individuals. Also, a 6-minute walk test was reduced in 15% of the patients and normal in 85% of the patients.
Conclusion:
Pulmonary function test can serve as an important tool in both diagnosis and follow-up of post-COVID lung fibrosis and pulmonary sequalae.
Journal Article
Improved Tapaswini having four BB resistance genes pyramided with six genes/QTLs, resistance/tolerance to biotic and abiotic stresses in rice
Rice, a major food crop, is grown in a wide range of ecological conditions and suffers significant yield losses as it is constantly exposed to a wide range of environmental and biotic stresses. The prevalence of different biotypes/strains has necessitated assembling of numerous resistance genes/QTLs into elite genotypes to confer a broader scale of resistance. The current study reports successful pyramiding of genes/QTLs that confer tolerance/resistance to submergence (
Sub1
), salinity (
Saltol
), blast (
Pi2
,
Pi9
) and gall midge (
Gm1
,
Gm4
) to supplement the four bacterial blight resistance genes (
Xa 4
,
xa5
,
xa13
,
Xa21
) present in Improved Tapaswini, an elite cultivar. The precise transfer of genes/QTLs was accomplished through effective foreground selection and suitable gene pyramids were identified. Background selection was practiced using morphological and grain quality traits to enhance the recovery of the recurrent parental genome. In the bioassays, the pyramids exhibited higher levels of resistance/ tolerance against the target stresses. The novel feature of the study was successful pyramidization and demonstration of the function of ten genes/QTLs in a new genotype. This success can stimulate several such studies to realize the full potential of molecular plant breeding as the foundation for rice improvement.
Journal Article