Ultrastrong and stiff layered polymer nanocomposites     

Podsiadlo P  Kaushik AK  Arruda EM  Waas AM  Shim BS  Xu J  Nandivada H  Pumplin BG  Lahann J  Ramamoorthy A  Kotov NA 《Science (New York, N.Y.)》2007,318(5847):80-83

Nanoscale building blocks are individually exceptionally strong because they are close to ideal, defect-free materials. It is, however, difficult to retain the ideal properties in macroscale composites. Bottom-up assembly of a clay/polymer nanocomposite allowed for the preparation of a homogeneous, optically transparent material with planar orientation of the alumosilicate nanosheets. The stiffness and tensile strength of these multilayer composites are one order of magnitude greater than those of analogous nanocomposites at a processing temperature that is much lower than those of ceramic or polymer materials with similar characteristics. A high level of ordering of the nanoscale building blocks, combined with dense covalent and hydrogen bonding and stiffening of the polymer chains, leads to highly effective load transfer between nanosheets and the polymer.  相似文献   

Evaluation of Ultrasound,Microwave, Ultrasound–Microwave,Hydrothermal and High Pressure Assisted Extraction Technologies for the Recovery of Phytochemicals and Antioxidants from Brown Macroalgae     

Marco Garcia-Vaquero  Rajeev Ravindran  Orla Walsh  John O&#x;Doherty  Amit K. Jaiswal  Brijesh K. Tiwari  Gaurav Rajauria 《Marine drugs》2021,19(6)

This study aims to explore novel extraction technologies (ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), ultrasound–microwave-assisted extraction (UMAE), hydrothermal-assisted extraction (HAE) and high-pressure-assisted extraction (HPAE)) and extraction time post-treatment (0 and 24 h) for the recovery of phytochemicals and associated antioxidant properties from Fucus vesiculosus and Pelvetia canaliculata. When using fixed extraction conditions (solvent: 50% ethanol; extraction time: 10 min; algae/solvent ratio: 1/10) for all the novel technologies, UAE generated extracts with the highest phytochemical contents from both macroalgae. The highest yields of compounds extracted from F. vesiculosus using UAE were: total phenolic content (445.0 ± 4.6 mg gallic acid equivalents/g), total phlorotannin content (362.9 ± 3.7 mg phloroglucinol equivalents/g), total flavonoid content (286.3 ± 7.8 mg quercetin equivalents/g) and total tannin content (189.1 ± 4.4 mg catechin equivalents/g). In the case of the antioxidant activities, the highest DPPH activities were achieved by UAE and UMAE from both macroalgae, while no clear pattern was recorded in the case of FRAP activities. The highest DPPH scavenging activities (112.5 ± 0.7 mg trolox equivalents/g) and FRAP activities (284.8 ± 2.2 mg trolox equivalents/g) were achieved from F. vesiculosus. Following the extraction treatment, an additional storage post-extraction (24 h) did not improve the yields of phytochemicals or antioxidant properties of the extracts.  相似文献   

Lignocellulosic biomass particle shape and size distribution analysis using digital image processing for pipeline hydro-transportation     

Mahdi Vaezi  Vivek Pandey  Amit Kumar  Souvik Bhattacharyya 《Biosystems Engineering》2013,114(2):97-112

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Fishing and trade of devil rays (Mobula spp.) in the Bay of Bengal,Bangladesh: Insights from fishers’ knowledge     

Alifa Bintha Haque  Nidhi Gloria D'Costa  Mahi Washim  Amit Robert Baroi  Nazia Hossain  Mashrur Hafiz  Sumaiya Rahman  Karabi Farhana Biswas 《水产资源保护:海洋与淡水生态系统》2021,31(6):1392-1409

1. Devil rays (Mobula spp.) are globally threatened cartilaginous fishes that have attracted global conservation concern owing to their high extinction risk and lack of protection in many countries. Limited resources and data on threatened marine species, including devil rays, impede conservation actions, particularly in developing countries, many of which have high biodiversity.
2. Devil ray catch is a component of artisanal fisheries in Bangladesh, but data on their fisheries and trade are limited. To characterize devil ray fishing practices, fishers’ perception and trade, 230 fishers and traders were interviewed between 4 June 2018 and 22 June 2019, in four areas of south-east Bangladesh. Catch data were also opportunistically collected at landing sites.
3. Six devil ray species were documented, caught in an array of gill nets, set-bag nets and longlines. All interviewed fishers reported life-long devil ray bycatch in some numbers, and also noted a decline in catch over the last decade. Bottom trawling, increased bycatch levels, increased demand for devil ray products and, in some cases, ecosystem changes were identified by fishers as threats to devil ray populations.
4. Unregulated and undocumented trade and retained bycatch, especially by gill nets and set-bag nets, are fuelled by local consumption of devil ray meat and international trade in meat and gill rakers. Compliance with international trade control treaties for all Mobula spp. or the Bangladeshi law protecting Mobula mobular was low, with the majority of fishers (87%, n = 174) unaware of their existence.
5. To manage devil ray fisheries, and prevent possible population declines, we propose a combination of legally enforced gear modifications, and catch and trade control through community-owned implementation strategies. Additionally, we propose the simultaneous implementation of inclusive, community-based awareness and stewardship projects in conjunction with a coast-wide ray monitoring programme. Finally, we emphasize that more research and action rooted in a sustainable fishery model is urgently needed to protect Bangladeshi devil ray populations.

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Modeling analysis of potential carbon sequestration under existing agroforestry systems in three districts of Indo-gangetic plains in India     

Ajit  S. K. Dhyani  Ramnewaj  A. K. Handa  Rajendra Prasad  Badre Alam  R. H. Rizvi  Garima Gupta  K. K. Pandey  Amit Jain  Uma 《Agroforestry Systems》2013,87(5):1129-1146

The Indo-gangetic plains (IGP) in India occupies 13 % of the total geographical area and produces 50 % of total food grain to feed 40 % population of the country. Dynamic CO2FIX model v3.1 has been used to assess the baseline (2011) carbon and to estimate the carbon sequestration potential (CSP) of agroforestry systems (AFS) for a simulation period of 30 years in three districts viz. Ludhiana (upper IGP in Punjab), Sultanpur (middle IGP in Uttar Pradesh) and Uttar Dinajpur (lower IGP in West Bengal) respectively. The estimated numbers of trees existing in farmer’s field on per hectare basis in these districts were 37.95, 6.14 and 6.20, respectively. The baseline standing biomass in the tree components varied from 2.45 to 2.88 Mg DM ha^?1 and the total biomass (tree + crop) from 11.14 to 25.97 Mg DM ha^?1 in the three districts. The soil organic carbon in the baseline ranged from 8.13 to 9.12 Mg C ha^?1 and is expected to increase from 8.63 to 24.51 Mg C ha^?1. The CSP of existing AFS (for 30 years simulation) has been estimated to the tune of 0.111, 0.126 and 0.551 Mg C ha^?1 year^?1 for Sultanpur, Dinajpur and Ludhiana districts, respectively. CSP of AFS increases with increasing tree density per hectare. Site specific climatic parameters like monthly temperature, annual precipitation and evapotranspiration also moderates the CSP of AFS. The preliminary estimates of the area under AFS’s were 2.06 % (3,256 ha), 2.08 % (6,440 ha) and 12.69 % (38,860 ha) in Sultanpur, Dinajpur and Ludhiana respectively.  相似文献   

Bending rigidity of thermally bonded nonwoven structures     

Amit Rawal 《Fibers and Polymers》2010,11(4):654-660

Bending rigidity is one of the most important parameters affecting the fabric drape characteristics. In this research work, classic Freeston and Platt model, describing the bending behaviour of nonwovens specifically for thermally bonded, has been modified by accounting for number of bonds replacing the number of fibres in a unit cell. These bonds are responsible for constraining the relative fiber motion in the nonwoven structure. The anisotropic characteristics of thermally bonded nonwovens are revealed by analysing the bending properties in various test directions. In general, there is a good agreement between the bending rigidity values obtained from modified Freeston and Platt model and experimental work. However, the classic Freeston and Platt model has overestimated the bending rigidity of thermally bonded nonwoven structures. Furthermore, the effect of main fiber parameters including volume fraction, modulus and orientation characteristics has been investigated on the bending rigidity of thermally bonded nonwovens.  相似文献   

Influence of planting date on growth, artemisinin yield, seed and oil yield of Artemisia annua L. under temperate climatic conditions     

R.K. Verma  Amit ChauhanR.S. Verma  A.K. Gupta 《Industrial Crops and Products》2011,34(1):860-864

Artemisia annua L. is an annual aromatic antibacterial herb, with effective antimalarial properties due to the presence of artemisinin. The intention of the present study was to establish plant survival, growth attributes, yield attributes and artemisinin yield of A. annua cv CIM - Arogya with different transplanting months in two cropping seasons (March 2005-February 2006 and March 2006-February 2007) under temperate climatic conditions of Himalaya, India. Artemisinin yield in the dried leaves was found maximum amongst the plants that were transplanted in March (24.39 kg ha⁻¹) and minimum in those transplanted in November (3.39 kg ha⁻¹).  相似文献   

A study on the effect of cadmium on the antioxidative defense system and alteration in different functional groups in castor bean and Indian mustard     

Kuldeep Bauddh  Amit Kumar  Sudhakar Srivastava  R.D. Tripathi 《Archives of Agronomy and Soil Science》2016,62(6):877-891

The present study was planned to delineate the role of antioxidants and different functional groups of Ricinus communis and Brassica juncea in the tolerance mechanisms toward cadmium (Cd) for phytoremediation. Application of Cd caused a reduction in dry biomass of 53.84% and 26.58% in root and 45.33% and 33.84% in shoots of B. juncea and R. communis, respectively. Antioxidant enzymes, namely superoxide dismutase, catalase, ascorbate peroxidase, guaiacol peroxidase, glutathione reductase and glutathione-S-transferase, and metabolites (proline) increased in both the species due to Cd exposure. The metal caused substantial changes in the functional groups present in the roots and leaves of the plants. A number of new peaks appeared in the Cd-treated plants, which indicate the production of the compounds responsible for the metal tolerance of these plants. R. communis has been found to possess a good antioxidant defense system against Cd stress and may be used for the phytoremediation of metal-contaminated soils in place of edible crops, which enhance the risk of contaminating the food chain. It has been observed that R. communis accumulated 213.39 and 335.68 mg Cd in roots and shoots, respectively, whereas B. juncea accumulated 28.19 and 310.15 mg Cd in the roots and shoots, respectively.  相似文献   

Micropropagation of mature Terminalia catappa (Indian Almond), a medicinally important forest tree     

Mahendra Phulwaria  Kheta Ram  Harish  Amit K. Gupta  N. S. Shekhawat 《Journal of Forest Research》2012,17(2):202-207

We report an efficient in vitro propagation method for Terminalia catappa using nodal segments of a 15-year-old mature tree. The nodal segments were cultured on MS medium supplemented with 6-benzyladenine (BA; 0.5–3.0 mg l⁻¹) or Kinetin (Kn; 0.5–3.0 mg l⁻¹) for bud breaking and multiple shoot induction. About 85% of the explant responded (2.8 ± 0.41 shoots per node with 2.7 ± 0.14 cm length) within 15 days of inoculation in Murashige and Skoog medium fortified with 2.0 mg l⁻¹ of BA. Further shoot multiplication was achieved by repeated transfer of mother explants and subculturing of in vitro-produced shoots on medium supplemented with various concentrations of BA (0.25–1.5 mg l⁻¹) or Kn (0.25–1.5 mg l⁻¹) or on their combinations. Optimal number of shoots and shoot length were recorded on MS medium supplemented with 0.25 mg l⁻¹ of BA and 0.25 mg l⁻¹ of Kn. The multiplied shoots were used for ex vitro rooting after treatment for 4 min with indole-3-butyric acid (IBA; 50–500 mg l⁻¹) or α-naphthalene acetic acid (NAA; 50–500 mg l⁻¹). About 80% of the shoots treated with 200 mg l⁻¹ of IBA produced ex vitro roots with an average of 2.8 roots per shoot. Nearly 75% of these plantlets could be acclimatized within 5 weeks and successfully established in the field. This is the first report on micropropagation of T. catappa, which can be applied for further genetic transformation assays and pharmaceutical purposes.  相似文献   

Effect of bypass fat supplementation on productive performance and blood biochemical profile in lactating Murrah (Bubalus bubalis) buffaloes     

Ranjan A  Sahoo B  Singh VK  Srivastava S  Singh SP  Pattanaik AK 《Tropical animal health and production》2012,44(7):1615-1621

The study investigated the effect of dietary supplementation of bypass fat on productive performance and blood biochemical profile of lactating Murrah buffaloes (Bubalus bubalis). Fifteen multiparous buffaloes (2-4 lactation) of early to mid lactation were divided in three homogenous groups T(1) (control), T(2), and T(3) of five each. The animals in T(1) were fed with a basal diet consisting of a concentrate mixture, green sorghum, and wheat straw as per requirements, while the animals in group T(2) and T(3) were fed with same ration supplemented with 0.7 % (100?g/day) and 1.4 % (200?g/day) bypass fat (on dry matter intake (DMI) basis), respectively. The feed intake, milk yield, and milk composition were not influenced by supplemental bypass fat. However, fat-corrected milk (6.5 %) yield was higher (P?相似文献