(PhysOrg.com) — Among the many applications of flexible thermoelectric materials is a wristwatch powered by the temperature difference between the human body and the surrounding environment. But if you wanted this watch made of low-cost carbon nanotube (CNT)/polymer materials, you would currently need a piece of fabric with an area of about 500 cm2, which is about 50 times greater than the area of a typical wristwatch. More information: Corey A. Hewitt, et al. “Multilayered Carbon Nanotube/Polymer Composite Based Thermoelectric Fabrics.” Nano Letters, Article ASAP. DOI: 10.1021/nl203806q In order to make such applications more practical, a team of researchers has developed a new multi-layer CNT/polymer design and demonstrated that it has a greatly increased power output compared to previous designs. The new CNT/polymer, which the researchers call “Power Felt,” also has the potential to be much less expensive than other thermoelectric materials.The research team, which includes Ph.D. student Corey Hewitt and Professor David Carroll from Wake Forest University, along with collaborators from other institutions, has published a paper on the new thermoelectric fabric design in a recent issue of Nano Letters.Although thermoelectrics have been studied and used commercially for several decades, they’re traditionally made of inorganic materials, such as bismuth telluride (Bi2Te3). But recent research has shown that organic materials could provide a promising alternative, with advantages such as low cost, ease of production, and flexibility. Yet for now, organic materials still lag behind inorganic ones in terms of performance. One of the keys for designing a high-performance thermoelectric fabric is creating a large temperature difference on opposite sides of the material. Since CNT/polymer thermoelectric materials are very thin, the temperature difference perpendicular to the film’s surface is limited. To address this problem, the researchers here designed a multi-layer CNT/polymer film that allows for the arrangement of the temperature gradient parallel to the film’s surface. The film consists of up to hundreds of alternating layers of conducting material (a polymer containing CNTs) and insulating material (pure polymer) bonded together. Each layer has a thickness of just 25-40 µm. When the fabric is subject to a temperature difference parallel to the surface, electrons or holes travel from the hot side to the cold side due to the Seebeck effect, which converts temperature difference into voltage. As the researchers explain, the amount of generated voltage (and total power output) is equal to the sum of contributions from each layer. So adding layers to the fabric is equivalent to adding voltage sources in series, and the number of layers is limited only by the heat source’s ability to produce a sufficient change in temperature throughout all the layers. Here, the heat source’s temperature is limited to 390 K (117 °C, 242 °F), the point at which the polymer begins deforming. Journal information: Nano Letters When the multi-layer fabric is exposed to a temperature gradient, charge carriers (electrons or holes) travel from the hot side to the cold side due to the Seebeck effect. The resulting voltage can be read across the ends of the first and last conduction layers. Image credit: Hewitt, et al. ©2012 American Chemical Society Explore further Experiments on a 72-layer fabric demonstrated a maximum power generation of 137 nW at a temperature difference of 50 K. But the researchers predict that the power output can be increased; for example, they calculate that a 300-layer fabric exposed to a 100 K temperature difference has a theoretical power output of up to 5 µW. From another perspective, the wristwatch mentioned above would require much less fabric than the current requirement of 500 cm2. “As presented, the areal requirement of our fabric is on the order of approximately 10 cm2,” Carroll told PhysOrg.com. “However, the point of the paper is to show that the fabric’s layers add somewhat linearly. This means that, as more layers are woven into the fabric (and these can be extraordinarily thin layers), the more power can be packed into a smaller area. So the fabric we show simply demonstrates this fact but doesn’t optimize it. Thus, it may take 10 cm2 of the fabric we show, but we have also made fabrics for which only a few cm2 could power the watch. And we could go further.”In terms of cost, if CNT/polymer thermoelectrics are produced on a large scale, the electricity they generate could cost as little as $1 per watt due to the low material cost and ease of production. In contrast, Bi2Te3 thermoelectrics currently generate electricity at a cost of about $7 per watt. As Carroll explained, the true test of the materials will be cost.“What is different in what we have done is to produce something in a form factor that allows for the application of large areas of the materials,” he said. “Thus, large amounts of power can be generated and, as long as the cost is low, then the $/W is competitive with other forms of energy capture. Of course this would not be possible without two major innovations in the paper. The first, as I have already pointed out, is the origami-like folding of the fabric that allows for the interlayers to add their power together. The second pertains to that ‘cost’ thing. Notice that we do not use pure carbon nanotube mats. Rather, our mats are primarily commodity polymers with nanotubes added. Thus the cost of the expensive element is kept to a minimum without sacrificing the overall performance.”The researchers predict that low-cost organic thermoelectric fabrics could have a multitude of applications. Besides the wristwatch, another wearable application could be winter jackets with thermoelectric inside liners that use the temperature difference between body heat and the outdoor temperature to power electronic devices, such as an iPod.Other potential applications include recapturing a car’s wasted heat energy in order to improve fuel mileage, and lining a vehicle’s seats with the fabric to provide electricity for the vehicle’s battery. If installed under roof shingles, the fabric could generate electricity on hot days to help lower a building’s electricity bills. And in emergencies, the fabric could potentially be used to power a cell phone or flashlight.“There are a very wide variety of applications for which these materials will now be perfectly adequate [with their current power output],” Carroll said. “Furthermore, if more power is required, there is the option of simply making larger sheets of fabric. Because of the cost advantages, this is still cheaper than going to more expensive Bi2Te3. Imagine, for instance, putting this material throughout the bodies of automobiles, supplying both sound dampening (which they must already do) and adding the functionality of power scavenging for only a nominal cost above the materials used currently. As with all organic electronics, the real transformative power of this innovation lies in its economic vs. technical advantages.”In the future, the researchers plan to further improve the power output of each film, using methods such as chemical treatment of the CNTs and increasing the electrical conductivity of the polymers. “Will we improve the performance? YES!” Carroll said. “We have already begun making significant advances in improving the overall power output and there is much more ground to cover. For you physics readers out there, the basic principle of suppressed phonon modes through scattering processes, coupled with fractal networks made of sections of phase coherent transport, is still young and we are confident we have not yet tapped into the real potential yet.” The flexible, lightweight CNT/polymer thermoelectric fabric contains hundreds of alternating layers of conducting and insulating material. Image credit: Hewitt, et al. ©2012 American Chemical Society Copyright 2012 PhysOrg.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. Citation: ‘Power Felt’ uses body heat to generate electricity (2012, February 28) retrieved 18 August 2019 from https://phys.org/news/2012-02-power-felt-body-electricity.html New nanotechnology converts heat into power when it’s needed most This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
Explore further © 2012 Phys.Org This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. More information: www.peratech.com/via Technology Review, CNET Citation: Electronic nose prototype may be worn for safety-sniffing (2012, May 12) retrieved 18 August 2019 from https://phys.org/news/2012-05-electronic-nose-prototype-worn-safety-sniffing.html
Now published in Scientific Reports, the results demonstrated that SMFs, IONPs and the collagen matrix were able to stimulate the proliferation, alkaline phosphatase production and mineralization of osteoblasts. The process was enabled by influencing matrix-cell interactions to influence the expression of Runx2, ON, BMP-2 and BMP-4. The collagen model offered insight to progressively form a novel mineralized 3-D bone model and understand magnetic stimulation on osteogenesis. Additional studies can be conducted with the model for applications in tissue engineering and regenerative medicine. In the U.K. alone, the number of patients suffering from bone fracture have a substantial economic impact on the quality of life as evidenced with costs to the National Health Services (NHS). During bone injury, the biological and mechanical process of physiological regeneration replaces the injured bone with new bone at the site of injury. The metabolic process is complicated and requires the interaction of many factors, including growth and differentiation factors such as hormones, cytokines and extracellular components; meanwhile inadequate or interrupted factors can lead to delayed healing or impaired/non-union of bone. The cellular and molecular mechanisms of magnetic stimulation-based bone regeneration require further understanding at present. To evaluate the phenomenon in the lab, a three-dimensional (3-D) native collagen model was recently developed via plastic compression to produce a cellular, dense and mechanically strong collagen structure. To produce cell-laden models in the study, Zhiyu Yuan and colleagues incorporated osteoblast cells (MG-63 cell line) and magnetic iron oxide nanoparticles (IONPs) into the collagen gels. Using 3-D printing, a magnetic bioreactor was designed and fabricated to support cell growth under static magnetic fields (SMFs). Using polymerase chain reaction (PCR), the researchers determined the impact of SMFs on the regulation and expression of genes related to osteogenesis including runt-related transcription factor 2 (Runx2), osteonectin (ON) and bone morphogenetic proteins 2 and 4 (BMP-2 and BMP-4). More information: Zhiyu Yuan et al. Development of a 3D Collagen Model for the In Vitro Evaluation of Magnetic-assisted Osteogenesis, Scientific Reports (2018). DOI: 10.1038/s41598-018-33455-2 Jon Dobson. Remote control of cellular behaviour with magnetic nanoparticles, Nature Nanotechnology (2008). DOI: 10.1038/nnano.2008.39 Aurelie G. Andrianarivo et al. Growth on type I collagen promotes expression of the osteoblastic phenotype in human osteosarcoma MG-63 cells, Journal of Cellular Physiology (2005). DOI: 10.1002/jcp.1041530205 In the study, the authors used a novel, multifunctional biomimetic 3-D collagen model for use as an in vitro platform to study mechanisms of magnetic stimulation on osteogenesis. To produce a range of cell-laden models, the researchers introduced internal stimuli (iron oxide nanoparticles) and external (static magnetic fields, SMFs) stimuli in to the system. The biomimetic material was engineered via the fabrication of nano- and microstructures using plastic compression, according to a previously established protocol. In order to evaluate biological behaviors of osteoblasts, including their proliferation, differentiation, mineralization, gene expression and microstructure analysis, the scientists cultured the collagen model in a magnetic bioreactor for up to 42 days. © 2018 Science X Network Citation: Developing a 3-D collagen model to test magnetic-assisted osteogenesis in vitro (2018, November 12) retrieved 18 August 2019 from https://phys.org/news/2018-11-d-collagen-magnetic-assisted-osteogenesis-vitro.html a) comparing ALP production of MG-63 cell line when cultured within collagen scaffolds with or without the incorporation of IONPs, with exposure to SMFs (M) and without exposure to SMFs. b) Comparing cell mineralization by extracting and quantifying ARS staining from scaffolds treated with or without SMFs exposure. Cell-loaded collagen scaffolds were integrated with IONPs (100 µg/ml) results were collected across 1, 21 and 42 days of culture. c) ARS staining of collagen scaffold in the absence of SMFs and IONPs, d) with SMFs, e) with IONPs, and f) with SMFs and IONPs. Credit: Scientific Reports, doi: 10.1038/s41598-018-33455-2. Engineering teratoma-derived fibroblasts to enhance osteogenesis Thereafter, the scientists conducted studies to understand responses of cell-seeded collagen scaffolds to SMFs and IONPs at the molecular level. For this, the expression levels of Runx2, ON, BMP-2 and BMP-4 were quantified using real-time quantitative polymerase chain reaction (RT-qPCR). A 7-day treatment of SMFs alone did not have an effect on the expression of Runx2, whereas increased expression was found when SMFs were combined with IONPs, demonstrating the collagen matrix mediated Runx2 expression during osteogenesis. At day 7 the level of ON expression in the samples treated with IONPs, SMFs and both were higher than in the control within a short period of time. During the expression of BMP-2 and BMP-4, similar results were observed across 7-14 days. , Nature Nanotechnology Explore further In the study, cell proliferation of the osteoblast cell line MG-63 was assessed using the alamarBlue assay. At day 14, the researchers observed a significant difference between SMFs alone, IONPs alone and in their combination on cell proliferation. Histology techniques were employed to examine cellular responses within the collagen scaffolds and understand the role of SMFs and IONPs on cell proliferation. Visualization was followed by quantitative analysis of cell numbers, results indicated that incorporation of IONPs prolonged the effect of SMFs. Similarly, cell differentiation was observed with alkaline phosphatase (ALP) activities for collagen scaffolds, with or without the incorporation of IONPs. As before, when the effect of IONPs and SMFs were combined the ALP production was significantly stimulated compared to treatment with SMFs alone and IONPs alone. Cell mineralization was also observed thereafter and quantified in the cell-seeded collagen scaffold. After 42 days all samples were stained with ARS staining to indicate complete mineralization. In contrast, combining SMFs and IONPs were unable to promote mineralization. , Journal of Cellular Physiology a) comparison of MG-63 cell proliferation when cultured with/without the incorporation of IONPs with exposure of SMFs (M) and without the exposure of SMFs. Cell proliferation can be enhanced with SMFs by incorporating IONPs, indicating a stimulating effect, b) Comparing the cell numbers of the MG-63 cell lines from histology images with or without SMFs. The cellular responses of the MG-63 cell line cultured on PC collagen scaffold were also examined via histology for conditions c) without SMFs and without IONPs, d) with SMFs, e) with IONPs and e) combining SMFs and IONPs. Credit: Scientific Reports, doi: 10.1038/s41598-018-33455-2. Journal information: Scientific Reports The study mainly demonstrated osteogenesis as a complex process mediated by successive activation and expression of several key genes, including Runx2, ON, BMP-2 and BMP-4. Typically, Runx2 upregulates the expression of protein genes related to the bone matrix to promote bone formation in vitro and in vivo. Accordingly, the study showed that SMF exposure may induce the cell line to proliferate by modulating early expression of Runx2, to accelerate osteogenesis. When IONPs were incorporated under SMFs, the expression of osteonectin (ON) gene increased, linking collagen phases with bone mineral to initiate normal skeletal tissue mineralization. Similarly, both BMP-2 and BMP-4 were only increased in the study during combined cell culture with SMFs and IONPs. In this way, the authors developed and tested a biomimetic 3-D collagen model that could progressively mineralize to subsequently form a novel bone model in vitro. The model was incorporated with osteoblast cells and nanoparticles with the ability to respond to external magnetic stimulations. The biomimetic collagen model was engineered via plastic compression to integrate the MG-63 cell line and demonstrate reproducible and consistent results combined with SMFs and IONPs. The cell-matrix interactions successfully upregulated the expression of key genes related to osteogenesis. The authors intend to develop the 3-D model further to serve as a superior platform to investigate biological behaviors in vitro with potential applications in tissue engineering and regenerative medicine. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. a) Microstructure of cell loaded collagen scaffolds examined under TEM. Cells are surrounded by the collagen matrix. The collagen fibrils showed no preferred direction around the cells under control conditions, b) IONPs can be identified in the collagen matrix and c) close to the cell membranes. After 14 days a new matrix was synthesized by the cells, d) without SMFs and e) with SMFs. Both conditions led to new matrix synthesis after 14 days, without a significant difference. Credit: Scientific Reports, doi: 10.1038/s41598-018-33455-2. Gene expression for a) Runx2, b) osteonectin (ON), c) BMP-2 and d) BMP-4 normalized with the control GAPDH after 7 and 14 days of cell culture. Credit: Scientific Reports, doi: 10.1038/s41598-018-33455-2.
This spectacular photo is a part of an exhibit called ‘Accessible Arctic’. The show was assembled and curated by the Canadian Museum of Nature.and Canadian Geographic. Together, they have formed a dynamic partnership to showcase Canada’s amazing natural history. The Accessible Arctic brings the beauty of the North closer to us as it speaks of its past, present and future. These quintessential images of nature and life in the arctic also remind us of the vast treasure that we hold in trust for future generations. The exhibition is being showcased in India, the timing of this exhibit marks Canada taking over the chair of the Arctic Council and India’s newly granted observer status at the Arctic Council.
Often said that your experience at the dawn of New Year’s is quite the script for the rest of the year ahead. Be it greatness of the food, the groove of the awe-inspiring music, or the beauty of the location where you are. The patrons at Escape’s Countdown Festival made sure that Delhiites take good time into 2014. The festival ringed in the New Year with the Ska Vengers performance at the Skinner stage while breathtaking fireworks lit the sky up. The Vibe stage on the other hand pumped up the trance rhythm as the clock struck 12. Also Read – ‘Playing Jojo was emotionally exhausting’An offshoot at Manesar – one of the coolest destination music festivals of the country – Escape-The Countdown Festival was the perfect year ender to unwind, the festival had 3 stages – Skinner, Vibe and the Boiler Room experience which featured spectacular music, along with art exhibitions, international cuisine alongside activities such as nature walks, mountain biking and rejuvenating spa treatments.The countdown festival showcased some of the finest musical performances from across the globe. The line-up at the festival had names like Antariksh, Big Bang Blues, Rusty Nails, The Ska Vengers, Aditi-Veena, Prateek Kuhad Collective, Jassb’stards, Jagramogara, Ectogasmics, Tadayan, Vaeya, Vipers vs K.T, Buffapirate, Frame / Frame, Shantam, Kumbhkaran, Blueorb, Curtain Blue, Guy called Sid Sal, Tech Panda, Post Modern Pandit, Uncoded followed by a new year’s brunch. Also Read – Leslie doing new comedy special with NetflixSpeaking about the Escape- The Countdown Festival, festival director L Tochhawng, said, ‘Simply put, how I wanted to bring in the New Year? With great music, non-stop festivity starting the 30th, going till the 1st noon, immersed in various genres of music, great food and a picturesque venue. It was a good start with a new festival to ring in the New Year. The last few years have made one thing very clear, we love our music festivals, so why not bid goodbye to the year gone by and bring in the New Year with a Mini Music Festival.’
Iraqi security forces have retaken most of the town of Jurf al-Sakhar near Baghdad from ISIS , the biggest gains in months of fighting for the strategic area, senior local officials said on Saturday. Full control of the town could allow Iraqi authorities to prevent the Sunni insurgents from edging closer to the capital and maintaining connections to their strongholds in western Anbar province as well as infiltrating the mainly Shia south. ‘We have managed to push out ISIS from the town of Jurf al-Sakhar and now we are raising the Iraqi flag over the government offices,’ provincial governor said. Some ISIS fighters had fled towards the city of Falluja while fighting still raged near a bridge linking Jurf al-Sakhar to Anbar.
On Tuesday, the Supreme Court, in the first open court hearing of the review petition of death sentence cases, had cleared the decks for Koli’s execution after it dismissed his plea seeking a review of the judgment.‘We are fully satisfied that this court has not committed any error that may persuade us to review the order,’ a bench of Chief Justice HL Dattu, Justice AR Dave and Justice SA Bobde had said. Koli’s lawyer, Ram Jethmalani, had argued that he was not given proper legal assistance to defend himself and that the entire evidence relied upon by the trial court in convicting and sentencing him to death showed that he was tortured by police to confess the crime. The autopsy report showed that the murder of 14 children was committed with the precision of a medical expert with the alleged objective of trading in organs, he argued. Also Read – Need to understand why law graduate’s natural choice is not legal profession: CJIJethmalani had said that in none of the 14 cases of killing was the torso of the dead recovered, pointing to the possible dimension of organ trade in the case. On 24 July, the apex court had rejected Koli’s plea seeking the recall of its 15 February, 2011 order upholding his death sentence in one of the 16 cases of rape and killing being faced by him. President Pranab Mukherjee had in July also rejected Koli’s mercy plea. He visited the Donation and Transplantation Institute Foundation, Barcelona, one of the leading centres of the world for research in organ transplantation housed in University of Barcelona University.The health ministry said the Indian organ and tissue donation and transplantation scenario is in for major development with the government committed to make National Organ and Tissue Transplant Organisation a world class institution. Regional centres will also be commissioned in six cities subsequently.
Art for Concern presents its annual show of traditional and folk art in an endeavour to help preserve and protect India’s artistic heritage. They bring the works of master craftsmen from across India. The proceeds from the sale of these artworks will go toward the grassroots programmes supported by Concern India Foundation. The show will be held on January 15 and 16 January at Balassi Institute, Hungarian Information and Cultural Centre, Janpath in the Capital. India is a land of fascinating folklores and magical myths which are represented in myriad traditional and folk art forms. Every part of the country has a special way of showcasing these stories in colourful forms, which are unfortunately running the risk of dying out because of inadequate exposure. Also Read – ‘Playing Jojo was emotionally exhausting’Art for Concern’s Traditional and Folk Art Show organised by Secure Giving is an attempt to showcase and preserve these indigenous art forms. Organised in aid of Concern India Foundation, the artworks at the Traditional and Folk Art exhibition are also available for sale. Being held in the capital for the very first time, the exhibition will showcase miniature art in various styles- Madhubani from Bihar, Mata ki Pachedi from Gujarat, Phad and Pichwai from Rajasthan, Gond from Madhya Pradesh, Kalamkari from Andhra Pradesh, Bronzes from Kumbakonam and Kalighat paintings from Kolkata. The Traditional and Folk Art Show is an attempt to give a window of exposure to the dying folk. According to Art for Concern’s Anjana Khanna, “The Traditional Art Show aims to promote traditional artists who have been practicing these art forms for years but are not getting enough exposure and recognition for their exceptional work.” Also Read – Leslie doing new comedy special with NetflixThe proceeds from the exhibition will go towards Concern India Foundation, a registered, non-profit charitable trust working towards ‘Helping People Help Themselves’ by making the disadvantaged self-reliant and enabling them to lead a life of dignity. Set up in 1991, Concern India Foundation works in the area of education, health and community development supporting over 270 programmes across the country.When: January 15-16 Where: Balassi Institute, Hungarian Information & Cultural Centre, 1-A, Janpath,
Kolkata: The elephant enclosure inside the Alipore Zoo that has been witnessing a facelift for the last few months will be ready in a month’s time. The new home for the pachyderms will be spanning over 3.7 acres, thrice the size of the old enclosure. The widening of the space became imperative after the Central Zoo Authority prodded the zoo authorities for increasing the space for free movement of the jumbos. “The enclosures for animals like leopards, hyena, and jackal needed to be shifted to another place to broaden the area of the elephants. Rani and Tithi — the two elephants are a major attraction in the zoo and particularly for the children. The waterbody at the front portion of the enclosure have been cleaned and beautified. Natural grass has been laid and shower has been fitted for the bathing of the elephants. The trees inside the new enclosure – Aswattha, Neem, Deodhar and Krishnachura – are surrounded by small brick walls so that the elephants can’t uproot them,” Zoo director Asis Kumar Samanta said adding that the animals love open space to roam around and enjoy the nature. It may be mentioned that in 2009, the Central Zoo Authority (CZA) banned elephants in zoos but had made an exception for Alipore zoo and had told officials that they could keep two elephants at the most by expanding the 3,000 sqm enclosure by at least three times. Also Read – Heavy rain hits traffic, flightsThe zoo authorities were again prodded by CZA in 2015-16 and there was apprehension that the Zoo will lose the jumbos because of not being able to meet the CZA guidelines for keeping the elephants. After a number of sleepless nights, the zoo authorities in consultation with experts chalked out a comprehensive plan for widening of the elephant enclosure. The elephants are presently kept in a shed in an enclosure out of public view while work is going on. “In the morning , their keeper popularly known as ‘mahoot’ takes them to the open space and allow them to roam around freely. They are extremely happy and we find it very difficult to take them back to the shed,” a senior zoo official said. The old elephant enclosure – with a moat, a shed and trees – was inaugurated in 1999 by the then chief minister Jyoti Basu. Before that, elephants used to remain chained in an enclosure one-tenth the size of the current one.
China’s military on Thursday asked the Indian Army not to take any “unilateral actions” affecting the stability of the border areas, days after the Indian side removed a Chinese-built hut in the Ladakh sector.“The recent actions by the Indian Army in the relevant area was not consistent with the relevant agreement and spirit of the consensus of the two sides,” China’s Defence Ministry spokesman Wu Qian said, commenting for the first time on the recent incident at Ladakh’s Burtse area in which the Indian army removed the hut along with surveillance cameras. Also Read – Nine hurt in accident at fireworks show in French resort“Jointly maintaining peace and tranquility of the India-China border is an important consensus reached between the leaderships of the two countries and also a solemn commitment and promise made by the two governments and militaries,” Wu, who took over as new spokesman of the People’s Liberation Army (PLA), said replying a question.“We ask the Indian army to earnestly implement the important consensus reached by the two governments and refrain from taking any unilateral actions which will