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Sample records for cell material karakterisasi

  1. Sintesis dan Karakterisasi Material Nanokomposit CNT/MnO2 Untuk Aplikasi Material Superkapasitor

    Directory of Open Access Journals (Sweden)

    A. Subagio

    2014-09-01

    Full Text Available Telah dilakukan fabrikasi material nanokomposit CNT/MnO2 sebagai material elektroda superkapasitor dengan reaksi redox antara CNT dan KMnO4. Variasi komposisi dari kedua bahan tersebut dilakukan untuk mengetahui sifat struktur, morfologi dan kelistrikannya dengan perbandingan massa CNT/MnO2 sebesar 0, 25, 50 dan 75%. Pola struktur kristal dan morfologi dari material serbuk nanokomposit CNT/MnO2 dikarakterisasi dengan X-ray diffraction (XRD, scanning electron microscope (SEM dan transmission electron microscope (TEM, sedangkan pola ikatannya dikarakterisasi dengan FTIR. Serbuk nanokomposit CNT/MnO2 ini selanjutnya dibuat pellet berbentuk silinder berukuran diameter 1 cm dan ketebalan 2 mm dengan variasi penambahan pengikat polyvinylidene difluoride (PVDF sebesar 10, 20 dan 30% dari campuran CNT/MnO2. Pellet dari material CNT/MnO2 ini selanjutnya dipanaskan pada temperatur 70 oC selama 1 jam. Hasil pengukuran resistansinya menunjukkan bahwa material CNT/MnO2 dengan perbandingan massa CNT/MnO2 sebesar 75% dan penambahan pengikat PVDF sebesar 20% menunjukkan nilai resistansi yang paling rendah. Selanjutnya prototip superkapasitor CNT/MnO2 dengan menggunakan PVDF sebesar 20% diukur dengan metode electrochemical impedance spectroscopy menghasilkan nilai kapasitansi spesifik sebesar 7,86 F/gr. Nanocomposite materials CNT/MnO2 have been fabricated as candidate of supercapacitor electrode material with a redox reaction between CNT and KMnO4. Variations in the composition of the two materials were carried out to determine the structure, morphology and electrical properties of CNT/MnO2 with mass ratio of 0, 25, 50 and 75 %. Pattern of the crystal structure and morphology of the CNT/MnO2 nanocomposite powder were characterized by X-ray diffraction (XRD, scanning electron microscope (SEM and transmission electron microscope (TEM, while the bond pattern was characterized by FTIR. CNT/MnO2 nanocomposite powder was managed to make cylindrical pellets with

  2. Karakterisasi stem cell pulpa gigi sulung dengan modifikasi enzim tripsin (The characterization of stem cells from human exfoliated deciduous teeth using trypsin enzym

    Directory of Open Access Journals (Sweden)

    Tri Wijayanti Puspitasari

    2014-06-01

    Full Text Available Background: Now a days, treatment in dentistry, using tissue regeneration that based on the stem cells from human exfoliated deciduous teeth (SHED, grows rapidly. For several reason, the isolated and cultured SHED is difficult to be applied in Indonesia, therefore the modification is needed. This difficulties were caused by the pulp anatomy, the heterogeneous populations in the pulp chamber and the limitations of tools and materials at the laboratory. Purpose: This research was aimed to examine that the modifications of isolation and culture technique of SHEDs for characterization by using the marker of CD105. Methods: The research was experimental laboratory with the cross sectional design. The samples were the human exfoliated deciduous teeth from the children patients of Pediatric Dentistry Department of Universitas Airlangga Dental Hospital which matched the criteria. Dental pulps were isolated and cultured by using the modifications of Trypsin enzymes. Results: The healthy SHEDs could be produced from the modifications of isolation and culture and positively shown the expression of marker CD105 which were indicated by the fluorencent microscope. Conclusion: SHED which isolated and cultured by using the modified techniques, positively characterized by using marker CD105.Latar Belakang: Pengobatan kedokteran gigi berkembang dengan pesat terutama di bidang regenerasi jaringan berbasis Stem Cells from Human Exfoliated Deciduous Teeth (SHED. Di Indonesia, isolasi dan kultur SHED sulit sehingga perlu dilakukan modifikasi. Kendala ini muncul karena jaringan pulpa yang kecil, heterogen dan keterbatasan alat dan bahan di laboratorium. Tujuan: Penelitian ini bertujuan untuk meneliti modifikasi pada cara isolasi dan kultur SHED untuk karakterisasi menggunakan maker CD105. Metode: Jenis penelitian ini adalah eksperimental laboratoris dengan rancangan cross sectional. Sampel penelitian adalah gigi sulung dari pasien anak di Klinik Kedokteran Gigi Anak

  3. KARAKTERISASI SIMPLISIA DAN EKSTRAK DAUN STROBILANTHUS CRISPUS

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    Ani Isnawati

    2012-10-01

    Full Text Available Khasiat obat tradisional disebabkan oleh adanya senyawa kimia yang  dikandungnya. Bahan baku obat dari hasil pertanian atau kumpulan tumbuhan liar tentunya kandungan kimianya tidak dapat dijamin selalu konstan (ajeg karena adanya variabel bibit, tempat tumbuh, iklim, kondisi (umur dan cara panen. Kandungan senyawa kimia yang bertanggung jawab terhadap respon biologis harus mempunyai spesifikasi kimia, yaitu informasi  komposisi (jenis dan kadar. 0leh karena itu penetapan karakterisasi suatu simplisia dan ekstrak perlu dilakukan guna menjamin bahwa bahan suatu produk obat tradisional dapat diketahui mutunya. Karakterisasi dilakukan terhadap Tanaman Strobilanthus crispus (BL, yaitu simplisia bagian daun dan ekstrak 50% tanaman tersebut. Karakterisasi simplisa meliputi : penetapan kadar abu, kadar abu larut air, kadar abu tidak larut asam, kadar sari larut air, kadar sari larut asam, dan kadar air secar·a destilasi. Cara penetapan diatas dilakukan sesuai prosedur yang Ielah ditetapkan MMI, 1979. Sedangkan karakterisasi ekstrak mencakup : karakterisasi non spesifik yang meliputi penetapan bobot  jenis, kadar air, kadar sisa pelarut, kadar abu dan karakterisasi spesifik yang mencakup  pemeriksaan·senyawa yang terlarut dalam pelarut air dan etanol, pola kromatografi dengan cara KLT-densitometri, pemeriksaan golongan kimia ekstrak dan penetapan kadar zat kimia. Hasil penetapan karakterisasi simplisia menunjukkan spesifikasi tidak sesuai dengan yang dipersyaratkan MMI, hanya penetapan sari larut etanol yang memenuhi persyaratan. Penetapan karakterisasi ekstrak etanol 50% menunjukkan tidak terdapat etanol dalam ekstrak, kadar air 13,3 %; bobot jenis 1,262%, senyawa terlarut dalam pelarut air 95,06%, senyawa terlarut dalam pelarut etanol 18,69 % dan kadar flavonoid  17,59 % serta  profil  kromatogram komponen utama fraksi heksan, Khloroform dan etanol.

  4. KARAKTERISASI FILM KOMPOSIT ALGINAT DAN KITOSAN

    Directory of Open Access Journals (Sweden)

    Nur Rokhati

    2012-11-01

    Full Text Available CHARACTERIZATION OF ALGINATE AND CHITOSAN COMPOSITE FILM. Due to the specific characteristics of (thin films, the use of polymer films in various aplications has singnificantly increased. Alginate and chitosan are natural polymers, which have potential as a raw material for the manufacture of composite films. This paper presents the preparation and characterization of alginate, chitosan and chitosan-alginate composite films. The film characterization included permeability test, degree of swelling, mechanical property, morphology (by SEM, and surface chemistry (by FTIR. The results showed that alginate films have a higher permeability ​​and degree of swelling (DS than chitosan films. Both permeability and DS decreased with increasing concentration for both alginate and chitosan films. DS experiments showed that the films have the highest DS in water followed by ethanol 95% and ethanol >99.9%, respectively. The mechanical strength of chitosan films was larger than alginate films. Alginate-chitosan composite films prepared by layer by layer method showed better characteristics than the composite films prepared by blending of alginate and chitosan solutions. Meningkatnya aplikasi film polimer di berbagai industri tidak terlepas dari keunggulan yang dimiliki. Alginat dan kitosan merupakan polimer alam yang mempunyai potensi sebagai bahan dasar pembuatan film komposit. Pada penelitian ini dilakukan pembuatan dan karakterisasi film komposit berbasis alginat dan kitosan. Karakterisasi film yang dilakukan meliputi uji: permeabilitas, derajat swelling, mekanik, morfologi (dengan SEM, dan struktur kimia permukaan (dengan FTIR. Hasil penelitian menunjukkan bahwa film alginat mempunyai nilai permeabilitas maupun derajat swelling yang lebih tinggi dibanding dengan film kitosan. Baik pada kitosan maupun alginat memberikan fenomena bahwa semakin besar konsentrasi larutan maka semakin kecil nilai permeabilitas maupun derajat swelling, dengan derajat

  5. KARAKTERISASI DAN UJI ANTIOSTEOPOROSIS EKSTRAK KAYU SECANG (Caesalpinia sappan)

    OpenAIRE

    Rifai, Yusnita; Subehan; Mufidah

    2008-01-01

    Abstrak, Standarisasi dan karakterisasi bahan obat dari bahan alam sangat penting untuk mendapatkan obat yang berkhasiat secara berkelanjutan dengan mutu yang terjamin. Salah satu bahan obat tradisional yang banyak digunakan adalah Secang (Caesalpinia sappan L.). Karakterisasi dilakukan terhadap tiga jenis ekstrak yang diperoleh dengan penyari n-heksan, metanol dan etanol 70%. Metode karakterisasi yang digunakan adalah secara spektrofotometer UV-Vis, FT-IR, TLC Scanner, dan KCKT. Analisis ren...

  6. Karakterisasi stem cell pulpa gigi sulung dengan modifikasi enzim tripsin (The characterization of stem cells from human exfoliated deciduous teeth using trypsin enzym)

    OpenAIRE

    Tri Wijayanti Puspitasari; Tania Saskianti; Udijanto Tedjosasongko

    2014-01-01

    Background: Now a days, treatment in dentistry, using tissue regeneration that based on the stem cells from human exfoliated deciduous teeth (SHED), grows rapidly. For several reason, the isolated and cultured SHED is difficult to be applied in Indonesia, therefore the modification is needed. This difficulties were caused by the pulp anatomy, the heterogeneous populations in the pulp chamber and the limitations of tools and materials at the laboratory. Purpose: This research was aimed to exam...

  7. Pembuatan Dan Karakterisasi Aspal Beton Berbasis Dreg Dan Grit

    OpenAIRE

    Newdesnetty Butarbutar

    2009-01-01

    Telah dilakukan penelitian tentang pembuatan dan karakterisasi aspal beton berbasis dreg dan grit. Penelitian ini dilakukan dengan metode pengadukan dengan menggunakan mixer beton, tujuan untuk memperoleh bahan aspal beton dari dreg dan grit untuk mengurangi volume pasir dengan variasi rasio pasir terhadap dreg dan grit adalah: 100 : 0 : 0; 90 : 5 : 5; 80 : 10 : 10; 70 : 15 : 15; 60 : 20 : 20; 50 : 25 : 25; 40 : 30 : 3; 30 : 35 : 35; 20 : 40 : 40; 10 : 45 : 45; 0 : 50 : 5...

  8. Karakterisasi Dan Ekstraksi Simplisia Tumbuhan Bunga Mawar (Rosa hybrida L.) Serta Formulasinya Dalam Sediaan Pewarna Bibir

    OpenAIRE

    Devi Farima

    2009-01-01

    Telah dilakukan karakterisasi dan skrining fitokimia terhadap simplisia bunga mawar (Rosa hybrida L.). Karakterisasi simplisia bunga mawar meliputi penetapan kadar air, penetapan kadar abu total, penetapan kadar abu tidak larut asam, penetapan kadar sari larut dalam air, dan penetapan kadar sari larut dalam etanol. Pembuatan ekstrak dari simplisia bunga mawar dilakukan dengan menggunakan pelarut etanol ditambah dengan asam asetat 3%. Formulasi sediaan pewarna bibir dibuat dal...

  9. ANALISIS KARAKTERISASI VIBRASI MOLEKUL SENYAWA ORGANIK FENOL, ASAM AKSALAT DAN ETIL ASETAT SECARA SPEKTOSKOPI INFRA MERAH

    OpenAIRE

    Bannu, S.Si., M.Si.

    2005-01-01

    Telah dilakukan penelitian Analisis Karakterisasi Vibrasi Melekul Senayawa Organik Fenol, Asam Oksalat dan Etil Asetat. Hasil Penelitian yang diamati : 1) frekuensi serapan vibrasi untuk masing-masing ikatan antar atom pada molekul Fenol, Asam Oksalat dan Etil Asetat; 2) konstanta gaya pada molekul Fenol, Asam Oksalat dan Etil Asetat; 3) panjang ikatan antar Atom; 4) konstanta tak harmonik ikatan antar atom; dan 5) energi disosiasi iktan antar atom. Karakterisasi dari ke tiga senyawa men...

  10. KARAKTERISASI DAUN KEMBANG SUNGSANG (Gloria superba (L DARI ASPEK FISIKO KIMIA

    Directory of Open Access Journals (Sweden)

    Ani Isnawati

    2012-10-01

    Full Text Available Khasiat obat tradisional ini berdasarkan adanya senyawa kimia yang dikandungnya. Sebagai bahan baku obat hasil pertanian atau kumpulan tumbuhan liar, kandungan kimianya tidak dapat dijamin selalu konstan mengingat adanya berbagai variabel, yaitu: bibit, tempat tumbuh, iklim, kondisi (umur dan cara panen. Sedangkan kandungan senyawa kimia yang bertanggung jawab terhadap respon biologis, harus mempunyai spesifikasi kimia, yaitu komposisi zat berkhasiat termasuk jenis dan kadar masing-masing. Berkaitan dengan hal tersebut di atas maka penetapan karakterisasi suatu simplisia dan ekstrak perlu dilakukan guna menjamin mutunya. Karakterisasi dilakukan terhadap simplisia bagian daun tanaman Kembang Sungsang (Gloria superba (L, dan ekstrak 50%. Karakterisasi simplisia meliputi: penetapan kadar abu, kadar abu larut air, kadar abu tidak larut asam, kadar sari larut air, kadar sari larut asam, dan kadar air secara destilasi. Cara penetapan di atas dilakukan sesuai prosedur yang telah ditetapkan MMI. Sedangkan karakterisasi ekstrak mencakup: karakterisasi non spesifik yang meliputi penetapan bobot jenis, kadar air, kadar sisa pelarut, kadar abu dan karakterisasi spesifik yang mencakup pemeriksaan senyawa yang terlarut dalam pelarut air dan etanol, pola kromatografi dengan cara KLT-densitometri, pemeriksaan golongan kimia ekstrak dan penetapan kadar zat kimia. Hasil penetapan karakterisasi simplisia menunjukkan spesifikasi: kadar air 9,95%, kadar abu 8,40%, kadar abu larut air 4,49%, kadar abu tidak larut asam 0,41%, kadar sari larut air 1,19%, kadar sari larut etanol 8,03%. Penetapan karakterisasi non spesifik ekstrak etanol 70% menunjukkan kadar air 12,7%, kadar abu 9,82%, kadar sari larut air, 82,67%, kadar saru larut etanol 9,53%, susut pengeringan 15,45% dan kadar sisa etanol 0,75%. Penetapan karakterisasi spesifik ekstrak etanol 70% menunjukkan kadar profil kromatogram dalam fraksi heksan pada panjang gelombang 254 nm 1 noda dan pada 365 nm 4 noda

  11. Solar cell materials developing technologies

    CERN Document Server

    Conibeer, Gavin J

    2014-01-01

    This book presents a comparison of solar cell materials, including both new materials based on organics, nanostructures and novel inorganics and developments in more traditional photovoltaic materials. It surveys the materials and materials trends in the field including third generation solar cells (multiple energy level cells, thermal approaches and the modification of the solar spectrum) with an eye firmly on low costs, energy efficiency and the use of abundant non-toxic materials.

  12. Microarrayed Materials for Stem Cells

    OpenAIRE

    Ying Mei

    2012-01-01

    Stem cells hold remarkable promise for applications in disease modeling, cancer therapy, and regenerative medicine. Despite the significant progress made during the last decade, designing materials to control stem cell fate remains challenging. As an alternative, materials microarray technology has received great attention because it allows for high throughput materials synthesis and screening at a reasonable cost. Here, we discuss recent developments in materials microarray technology and th...

  13. Materials for fuel cells

    Directory of Open Access Journals (Sweden)

    Sossina M Haile

    2003-03-01

    Full Text Available Because of their potential to reduce the environmental impact and geopolitical consequences of the use of fossil fuels, fuel cells have emerged as tantalizing alternatives to combustion engines. Like a combustion engine, a fuel cell uses some sort of chemical fuel as its energy source but, like a battery, the chemical energy is directly converted to electrical energy, without an often messy and relatively inefficient combustion step. In addition to high efficiency and low emissions, fuel cells are attractive for their modular and distributed nature, and zero noise pollution. They will also play an essential role in any future hydrogen fuel economy.

  14. Potential Materials for Fuel Cells

    Science.gov (United States)

    Kolli, Sri Harsha

    Proton exchange membrane fuel cells have attracted immense research activities from the inception of the technology due to its high stability and performance capabilities. The major obstacle from commercialization is the cost of the catalyst material in manufacturing the fuel cell. In the present study, the major focus in PEMFCs has been in reduction of the cost of the catalyst material using graphene, thin film coated and Organometallic Molecular catalysts. The present research is focused on improving the durability and active surface area of the catalyst materials with low platinum loading using nanomaterials to reduce the effective cost of the fuel cells. Performance, Electrochemical impedance spectroscopy, oxygen reduction and surface morphology studies were performed on each manufactured material. Alkaline fuel cells with anion exchange membrane get immense attention due to very attractive opportunity of using non-noble metal catalyst materials. In the present study, cathodes with various organometallic cathode materials were prepared and investigated for alkaline membrane fuel cells for oxygen reduction and performance studies. Co and Fe Phthalocyanine catalyst materials were deposited on multi-walled carbon nanotubes (MWCNTs) support materials. Membrane Electrode Assemblies (MEAs) were fabricated using Tokuyama Membrane (#A901) with cathodes containing Co and Fe Phthalocyanine/MWCNTs and Pt/C anodes. Fuel cell performance of the MEAs was examined.

  15. Separator material for electrochemical cells

    Science.gov (United States)

    Cieslak, Wendy R.; Storz, Leonard J.

    1991-01-01

    An electrochemical cell characterized as utilizing an aramid fiber as a separator material. The aramid fibers are especially suited for lithium/thionyl chloride battery systems. The battery separator made of aramid fibers possesses superior mechanical strength, chemical resistance, and is flame retardant.

  16. Materials for low-temperature fuel cells

    CERN Document Server

    Ladewig, Bradley; Yan, Yushan; Lu, Max

    2014-01-01

    There are a large number of books available on fuel cells; however, the majority are on specific types of fuel cells such as solid oxide fuel cells, proton exchange membrane fuel cells, or on specific technical aspects of fuel cells, e.g., the system or stack engineering. Thus, there is a need for a book focused on materials requirements in fuel cells. Key Materials in Low-Temperature Fuel Cells is a concise source of the most important and key materials and catalysts in low-temperature fuel cells. A related book will cover key materials in high-temperature fuel cells. The two books form part

  17. Materials for high-temperature fuel cells

    CERN Document Server

    Jiang, San Ping; Lu, Max

    2013-01-01

    There are a large number of books available on fuel cells; however, the majority are on specific types of fuel cells such as solid oxide fuel cells, proton exchange membrane fuel cells, or on specific technical aspects of fuel cells, e.g., the system or stack engineering. Thus, there is a need for a book focused on materials requirements in fuel cells. Key Materials in High-Temperature Fuel Cells is a concise source of the most important and key materials and catalysts in high-temperature fuel cells with emphasis on the most important solid oxide fuel cells. A related book will cover key mater

  18. Karakterisasi talas (Colocasia esculenta berdasarkkan penanda morfologi dan pola pita isozim

    Directory of Open Access Journals (Sweden)

    SAJIDAN

    2011-05-01

    Full Text Available Trimanto, Sajidan, Sugiyarto. 2011. Karakterisasi talas (Colocasia esculenta berdasarkan penanda morfologi dan pola pita isozim. Bioteknologi 8: 32-41. Tujuan penelitian ini adalah untuk mengetahui: (i keragaman Colocasia esculenta berdasarkan karakter morfologi; (ii keragaman C. esculenta berdasarkan pola pita isozim, dan (iiii hubungan jarak genetik berdasarkan karakter morfologi dan pola pita isozim. Survei penelitian dilakukan di Kabupaten Karanganyar, di ketinggian tinggi, sedang dan rendah. Sampel diambil menggunakan teknik random sampling purposif, mencakup 9 titik cuplikan. Data morfologi diuraikan secara deskriptif dan kemudian dibuat dendogram kekerabatan. Data pola pita isozim dianalisis secara kuantitatif berdasarkan ada atau tidaknya pita di gel, kemudian dibuat dendogramnya. Korelasi berdasarkan karakter morfologi dan pola pita isozim dianalisis berd asarkan korelasi koefisien momen-produk kriteria goodness of fit. Hasil penelitian menunjukan: (i di Karanganyar terdapat 10 varietas C. esculenta; (ii karakter morfologi tidak terpengaruh oleh ketinggian; (iii peroksidase membentuk 14 pola pita isozim, esterase membentuk 11 pola pita dan shikimate dehidrogenase membentuk 15 pola pita; (iv data morfologi dengan isozim peroksidase memiliki korelasi yang baik ( 0,893542288, sementara data morfologi dengan isozim esterase dan shikimate dehidrogenase memiliki korelasi yang sangat baik (0,917557716 dan 0,9121985446; (v data pola pita isozim mendukung data karakter morfologi.

  19. Pembuatan dan Karakterisasi Kertas Dari Daun Nanas dan Eceng Gondok

    OpenAIRE

    Ayunda, Vivien

    2015-01-01

    Research on the production and characterization of paper made from a mixture of pineapple leaf and water hyacinth has been done. The research was conducted using semi-chemical, aiming to obtain an alternative raw material for paper and find out the optimum composition of the mixture of pulp pineapple leaf and water hyacinth. Variations of the mixture is 100:0%, 80:20%, 60:40%, 40:60%, 20:80%, 0:100%. Pineapple lef and water hyacinth cooked using a 1,5% solution of NaOH, at a temperature of 10...

  20. PREPARASI DAN KARAKTERISASI KITIN DARI KULIT UDANG PUTIH (Litophenaeus vannamei

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    Mardiyah Kurniasih

    2007-11-01

    Full Text Available Chitin is one of the most abundant natural polysaccharides produced by many living organisms; it is usually found as a component of crustacean shells. In this paper, Chitin have been isolated from white shrimp (Litophenaeus vannamei. The preparation of chitin using chemical products to deproteinize and demineralize the source material. Characterization included determination of water, ash, fat and protein degree; moreover chitin powder characterize with FTIR and XRD spectroscopy. The result showed that process efficiency of chitin from white shrimp (Litophenaeus vannamei was 20.95%, with degree of water, ash, fat and protein were 5.39, 2.66, 1.54 and 36.16%, respectively.

  1. Semiconductor materials for solar photovoltaic cells

    CERN Document Server

    Wong-Ng, Winnie; Bhattacharya, Raghu

    2016-01-01

    This book reviews the current status of semiconductor materials for conversion of sunlight to electricity, and highlights advances in both basic science and manufacturing.  Photovoltaic (PV) solar electric technology will be a significant contributor to world energy supplies when reliable, efficient PV power products are manufactured in large volumes at low cost.  Expert chapters cover the full range of semiconductor materials for solar-to-electricity conversion, from crystalline silicon and amorphous silicon to cadmium telluride, copper indium gallium sulfide selenides, dye sensitized solar cells, organic solar cells, and environmentally friendly copper zinc tin sulfide selenides. The latest methods for synthesis and characterization of solar cell materials are described, together with techniques for measuring solar cell efficiency. Semiconductor Materials for Solar Photovoltaic Cells presents the current state of the art as well as key details about future strategies to increase the efficiency and reduce ...

  2. Sealant materials for solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Krumpelt, M.

    1995-08-01

    The objective of this work is to complete the development of soft glass-ceramic sealants for the solid oxide fuel cell (SOFC). Among other requirements, the materials must soften at the operation temperature of the fuel cell (600-1000{degrees}C) to relieve stresses between stack components, and their thermal expansions must be tailored to match those of the stack materials. Specific objectives included addressing the needs of industrial fuel cell developers, based on their evaluation of samples we supply, as well as working with commercial glass producers to achieve scaled-up production of the materials without changing their properties.

  3. Diamond cells and new materials

    Directory of Open Access Journals (Sweden)

    Reinhard Boehler

    2005-11-01

    Full Text Available The diamond anvil apparatus, invented nearly 50 years ago, has developed into a versatile tool for a broad spectrum of high-pressure research topics, ranging from low-temperature physics to high-temperature geoscience. It is superbly suited for high-pressure and high-temperature synthesis because new materials can be identified and characterized in situ. The combination of high pressure and high temperature, generated by two opposed diamond anvils and infrared (IR lasers, respectively, has allowed the simulation of the extreme conditions of planetary interiors, the discovery of new structures and behavior in elements, and the synthesis of novel hard materials. Here, we describe the relatively simple technique of generating and controlling high pressure and high temperature, and present recent examples related to these topics.

  4. Hot cells preparation of testing materials

    International Nuclear Information System (INIS)

    It is important in nuclear waste repository development that testing be done with materials containing a radionuclide spectrum representative of actual wastes. To meet the need for such materials, the Materials Characterization Center (MCC) has prepared simulated high-level waste (HLW) glasses with radionuclides representative of about 10-, 300- and 100-year-old waste. A quantity of well characterized spent fuel also has been acquired for the same purpose. Glasses containing 10- and 300-year-old wastes, and the spent fuel specimens, must be fabricated in a hot cell. Hot cell conditions (high radiation field, remote operation, and difficulty of repairs) require that procedures and equipment normally used in materials preparation out-of-cell be modified for hot cell applications. This paper discusses the fabrication of two glasses, and the preparation of test specimens of these glasses and spent fuel. One of the glasses is a 76-68 composition, which is fully loaded with actual commercial reactor fission product waste. The other glass contains simulated Barnwell Nuclear Fuel Plant waste, doped with different combinations of fission products and actinides. The spent fuel is a 10-year-old PWR material. Special techniques have been used to achieve high quality, well characterized testing materials, including specimens in the form of segments, wafers, cylinders, and powders of these materials

  5. Advanced materials for solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, T.R.; Stevenson, J.

    1995-08-01

    The purpose of this research is to improve the properties of the current state-of-the-art materials used for solid oxide fuel cells (SOFCs). The objectives are to: (1) develop materials based on modifications of the state-of-the-art materials; (2) minimize or eliminate stability problems in the cathode, anode, and interconnect; (3) Electrochemically evaluate (in reproducible and controlled laboratory tests) the current state-of-the-art air electrode materials and cathode/electrolyte interfacial properties; (4) Develop accelerated electrochemical test methods to evaluate the performance of SOFCs under controlled and reproducible conditions; and (5) Develop and test materials for use in low-temperature SOFCs. The goal is to modify and improve the current state-of-the-art materials and minimize the total number of cations in each material to avoid negative effects on the materials properties. Materials to reduce potential deleterious interactions, (3) improve thermal, electrical, and electrochemical properties, (4) develop methods to synthesize both state-of-the-art and alternative materials for the simultaneous fabricatoin and consolidation in air of the interconnections and electrodes with the solid electrolyte, and (5) understand electrochemical reactions at materials interfaces and the effects of component composition and processing on those reactions.

  6. Stability of solid oxide fuel cell materials

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, T.R.; Bates, J.L.; Chick, L.A. [Pacific Northwest Lab., Richland, WA (United States)

    1996-04-01

    Interconnection materials in a solid oxide fuel cell are exposed to both highly oxidizing conditions at the cathode and to highly reducing conditions at the anode. The thermal expansion characteristics of substituted lanthanum and yttrium chromite interconnect materials were evaluated by dilatometry as a function of oxygen partial pressures from 1 atm to 10{sup -18} atm, controlled using a carbon dioxide/hydrogen buffer.

  7. Engineering Cell Instructive Materials To Control Cell Fate and Functions through Material Cues and Surface Patterning.

    Science.gov (United States)

    Ventre, Maurizio; Netti, Paolo A

    2016-06-22

    Mastering the interaction between cells and extracellular environment is a fundamental prerequisite in order to engineer functional biomaterial interfaces able to instruct cells with specific commands. Such advanced biomaterials might find relevant application in prosthesis design, tissue engineering, diagnostics and stem cell biology. Because of the highly complex, dynamic, and multifaceted context, a thorough understanding of the cell-material crosstalk has not been achieved yet; however, a variety of material features including biological cues, topography, and mechanical properties have been proved to impact the strength and the nature of the cell-material interaction, eventually affecting cell fate and functions. Although the nature of these three signals may appear very different, they are equated by their participation in the same material-cytoskeleton crosstalk pathway as they regulate cell adhesion events. In this work we present recent and relevant findings on the material-induced cell responses, with a particular emphasis on how the presentation of biochemical/biophysical signals modulates cell behavior. Finally, we summarize and discuss the literature data to draw out unifying elements concerning cell recognition of and reaction to signals displayed by material surfaces. PMID:26693600

  8. Materials availability for thin film solar cells

    Science.gov (United States)

    Makita, Yunosuke

    1997-04-01

    Materials availability is one of the most important factors when we consider the mass-production of next generation photovoltaic devices. "In (indium)" is a vital element to produce high efficient thin film solar cells such as InP and CuIn(Ga)Se2 but its lifetime as a natural resource is suggested to be of order of 10˜15 years. The lifetime of a specific natural resource as an element to produce useful device substances is directly related with its abundance in the earth's crust, consumption rate and recycling rate (if recycling is economically meaningful). The chemical elements having long lifetime as a natural resource are those existing in the atmosphere such as N (nitrogen) and O (oxygen); the rich elements in the earth's crust such as Si, Ca, Sr and Ba; the mass-used metals such as Fe (iron), Al (aluminum) and Cu (copper) that reached the stage of large-scale recycling. We here propose a new paradigm of semiconductor material-science for the future generation thin film solar cells in which only abundant chemical elements are used. It is important to remark that these abundant chemical elements are normally not toxic and are fairly friendly to the environment. β-FeSi2 is composed of two most abundant and nontoxic chemical elements. This material is one of the most promising device materials for future generation energy devices (solar cells and thermoelectric device that is most efficient at temperature range of 700-900 °C). One should remind of the versatility of β-FeSi2 that this material can be used not only as energy devices but also as photodetector, light emitting diode and/or laser diode at the wavelength of 1.5 μm that can be monolithically integrated on Si substrates due to the relatively small lattice mismatch.

  9. Stability of solid oxide fuel cell materials

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, T.R.; Bates, J.L.; Coffey, G.W.; Pederson, L.R. [Pacific Northwest National Lab., Richland, WA (United States)] [and others

    1996-08-01

    Chromite interconnection materials in an SOFC are exposed to both highly oxidizing conditions at the cathode and to highly reducing conditions at the anode. Because such conditions could lead to component failure, the authors have evaluated thermal, electrical, chemical, and structural stabilities of these materials as a function of temperature and oxygen partial pressure. The crystal lattice of the chromites was shown to expand for oxygen partial pressures smaller than 10{sup {minus}10} atm, which could lead to cracking and debonding in an SOFC. Highly substituted lanthanum chromite compositions were the most susceptible to lattice expansion; yttrium chromites showed better dimensional stability by more than a factor of two. New chromite compositions were developed that showed little tendency for lattice expansion under strongly reducing conditions, yet provided a good thermal expansion match to other fuel cell components. Use of these new chromite interconnect compositions should improve long-term SOFC performance, particularly for planar cell configurations. Thermodynamic properties of substituted lanthanum manganite cathode compositions have been determined through measurement of electromotive force as a function of temperature. Critical oxygen decomposition pressures for Sr and Ca-substituted lanthanum manganites were established using cells based on a zirconia electrolyte. Strontium oxide and calcium oxide activities in a lanthanum manganite matrix were determined using cells based on strontium fluoride and calcium fluoride electrolytes, respectively. The compositional range of single-phase behavior of these ABO{sub 3}-type perovskites was established as a function of A/B cation ratios and the extent of acceptor doping. Before this work, very little thermodynamic information was in existence for substituted manganite compositions. Such information is needed to predict the long-term stability of solid oxide fuel cell assemblies.

  10. Materials Challenges for Automotive PEM Fuel Cells

    Science.gov (United States)

    Gasteiger, Hubert

    2004-03-01

    Over the past few years, significant R efforts aimed at meeting the challenging cost and performance targets required for the use of Polymer Electrolyte Membrane (PEM) fuel cells in automotive applications. Besides engineering advances in bipolar plate materials and design, the optimization of membrane-electrode assemblies (MEAs) was an important enabler in reducing the cost and performance gaps towards commercial viability for the automotive market. On the one hand, platinum loadings were reduced from several mgPt/cm2MEA [1] to values of 0.5-0.6 mgPt/cm2MEA in current applications and loadings as low as 0.25 mgPt/cm2MEA have been demonstrated on the research level [2]. On the other hand, implementation of thin membranes (20-30 micrometer) [3, 4] as well as improvements in diffusion medium materials, essentially doubled the achievable power density of MEAs to ca. 0.9 W/cm2MEA (at 0.65 V) [5], thereby not only reducing the size of a PEMFC fuel cell system, but also reducing its overall materials cost (controlled to a large extent by membrane and Pt-catalyst cost). While this demonstrated a clear path towards automotive applications, a renewed focus of R efforts is now required to develop materials and fundamental materials understanding to assure long-term durability of PEM fuel cells. This presentation therefore will discuss the state-of-the-art knowledge of catalyst, catalyst-support, and membrane degradation mechanisms. In the area of Pt-catalysts, experience with phosphoric acid fuel cells (PAFCs) has shown that platinum sintering leads to long-term performance losses [6]. While this is less critical at the lower PEMFC operating temperatures (200C), very little is known about the dependence of Pt-sintering on temperature, cell voltage, and catalyst type (i.e., Pt versus Pt-alloys) and will be discussed here. Similarly, carbon-support corrosion can contribute significantly to voltage degradation in PAFCs [7], and even in the PEMFC environment more corrosion

  11. Energy converting material for solar cell application

    Science.gov (United States)

    Pokhrel, Madhab; Kumar, G. A.; Sardar, Dhiraj K.

    2012-02-01

    In this paper, we discuss the concept of an efficient infrared upconverting phosphor as an energy converting material that could potentially improve the efficiency of Si solar cells in bifacial configuration. Basic spectroscopic studies of Yb and Er-doped La2O2S phosphor was reported with particular attention to its upconversion properties under 1550 nm excitation. Different concentrations of phosphors were synthesized by solid state flux fusion method. The phosphor powders were well crystallized in a hexagonal shape with an average size 300-400 nm. The most efficient upconverting sample (1%Yb: 9% Er doped La2O2S) was also studied under the illumination with infrared (IR) broad band spectrum above 1000 nm. Our measurements show that even with an excitation power density of 0.159 W/cm2 using a tungsten halogen lamp the material shows efficient upconversion corroborating the fact that the present phosphors could be potential candidates for improving the efficiency of the present Si solar cells.

  12. Sealing materials for solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, P.H.

    1999-02-01

    A major obstacle in the achievement of high electrical efficiency for planar solid oxide fuel cell stacks (SOFC) is the need for long term stable seals at the operational temperature between 850 and 1000 deg. C. In the present work the formation and properties of sealing materials for SOFC stacks that fulfil the necessary requirements were investigated. The work comprises analysis of sealing material properties independently, in simple systems as well as tests in real SOFC stacks. The analysed sealing materials were based on pure glasses or glass-ceramic composites having B{sub 2}O{sub 3}, P{sub 2}O{sub 5} or siO{sub 2} as glass formers, and the following four glass systems were investigated: MgO/caO/Cr{sub 2}O{sub 3}-Al{sub 2}O{sub 3}B{sub 2}O{sub 3}-P{sub 2}O{sub 5}, MgO-Al{sub 2}O{sub 3}-P{sub 2}O{sub 5}, MgO-Al{sub 2}O{sub 3}-P{sub 2}O{sub 5}-SiO{sub 2} and BaO/Na{sub 2}O-Al{sub 2}O{sub 3}-SiO{sub 2}. (au) 32 tabs., 106 ills., 107 refs.

  13. Metallic materials in solid oxide fuel cells

    Directory of Open Access Journals (Sweden)

    Willem Joseph Quadakkers

    2004-03-01

    Full Text Available Fe-Cr alloys with variations in chromium content and additions of different elements were studied for potential application in intermediate temperature Solid Oxide Fuel Cell (SOFC. Recently, a new type of FeCrMn(Ti/La based ferritic steels has been developed to be used as construction material for SOFC interconnects. In the present paper, the long term oxidation resistance of this class of steels in both air and simulated anode gas will be discussed and compared with the behaviour of a number of commercial available ferritic steels. Besides, in-situ studies were carried out to characterize the high temperature conductivity of the oxide scales formed under these conditions. Main emphasis will be put on the growth and adherence of the oxide scales formed during exposure, their contact resistance at service temperature as well as their interaction with various perovskite type contact materials. Additionally, parameters and protection methods in respect to the volatilization of chromia based oxide scales will be illustrated.

  14. Center for Intelligent Fuel Cell Materials Design

    Energy Technology Data Exchange (ETDEWEB)

    Santurri, P.R., (Chemsultants International); Hartmann-Thompson, C.; Keinath, S.E. (Michigan Molecular Inst.)

    2008-08-26

    The goal of this work was to develop a composite proton exchange membrane utilizing 1) readily available, low cost materials 2) readily modified and 3) easily processed to meet the chemical, mechanical and electrical requirements of high temperature PEM fuel cells. One of the primary goals was to produce a conducting polymer that met the criteria for strength, binding capability for additives, chemical stability, dimensional stability and good conductivity. In addition compatible, specialty nanoparticles were synthesized to provide water management and enhanced conductivity. The combination of these components in a multilayered, composite PEM has demonstrated improved conductivity at high temperatures and low humidity over commercially available polymers. The research reported in this final document has greatly increased the knowledge base related to post sulfonation of chemically and mechanically stable engineered polymers (Radel). Both electrical and strength factors for the degree of post sulfonation far exceed previous data, indicating the potential use of these materials in suitable proton exchange membrane architectures for the development of fuel cells. In addition compatible, hydrophilic, conductive nano-structures have been synthesized and incorporated into unique proton exchange membrane architectures. The use of post sulfonation for the engineered polymer and nano-particle provide cost effective techniques to produce the required components of a proton exchange membrane. The development of a multilayer proton exchange membrane as described in our work has produced a highly stable membrane at 170°C with conductivities exceeding commercially available proton exchange membranes at high temperatures and low humidity. The components and architecture of the proton exchange membrane discussed will provide low cost components for the portable market and potentially the transportation market. The development of unique components and membrane architecture

  15. Materials for the stem cell factories of the future

    OpenAIRE

    Alexander, Morgan R.

    2014-01-01

    The materials community is now identifying polymeric substrates that could permit translation of human pluripotent stem cells (hPSCs) from lab-based research to industrial scale biomedicine. Well defined materials are required to allow cell banking and to provide the raw material for reproducible differentiation into lineages for large scale drug screening programs and clinical use, wherein >1 billion cells for each patient are needed to replace losses during heart attack, multiple sclerosis ...

  16. Chemistry and material science at the cell surface

    OpenAIRE

    Weian Zhao; Grace Sock Leng Teo; Namit Kumar; Karp, Jeffrey M.

    2010-01-01

    Cell surfaces are fertile ground for chemists and material scientists to manipulate or augment cell functions and phenotypes. This not only helps to answer basic biology questions but also has diagnostic and therapeutic applications. In this review, we summarize the most recent advances in the engineering of the cell surface. In particular, we focus on the potential applications of surface engineered cells for 1) targeting cells to desirable sites in cell therapy, 2) programming assembly of c...

  17. SINTESIS DAN KARAKTERISASI BIODIESEL DARI MINYAK KEMIRI SUNAN (Reutealis trisperma Oil DENGAN KATALIS KOH (VARIASI KONSENTRASI KATALIS

    Directory of Open Access Journals (Sweden)

    SD Anggraini

    2014-06-01

    Full Text Available Abstrak __________________________________________________________________________________________ Pada penelitian ini new feedstock biodesel diproduksi dari crude minyak kemiri sunan (Reutealis Trisperma-Oil (RETRO. RETRO adalah minyak tumbuhan yang melimpah di Indonesia dan belum tereksploitasi dikarenakan sifatnya yang beracun. RETRO disiapkan melalui reaksi esterifikasi dengan metanol menggunakan katalis asam sulfat untuk menurunkan nilai Free Fatty Acid (FFA dan dilanjutkan reaksi transesterifikasi dengan metanol dan katalis basa. Reaksi transesterifikasi RETRO menggunakan katalis kalsium hidroksida (KOH pada variasi 0,5–2,0 %wt minyak telah dilakukan pada suhu 65 °C. Hasil penelitian menunjukkan bahwa yield biodesel meningkat dengan meningkatnya konsentrasi katalis (pada 0,5-1,0 %wt dan menurun dengan konsentrasi katalis (pada 1,5-2.0 %wt. Hasil Fatty Acid Methyl Ester (FAME optimum sebesar 83,33% diperoleh dengan menggunakan katalis KOH dengan konsentrasi katalis 1 %wt minyak. Karakterisasi hasil biodesel RETRO dilakukan dengan membandingkannya dengan ASTM D6751-02 diperoleh angka asam 0,55 mgKOH/g, densitas 0,90 g/cm3, viskositas 10,6 cSt pada suhu 40 oC, angka setana 54,7 serta residu karbon 0,24%.   Abstract __________________________________________________________________________________________ In this research new feedstock biodiesel was produced from Crude Reutealis Trisperma-Oil (RETRO. RETRO is vegetable oil that is overabundance in Indonesia it has not been explored because of its toxicity. RETRO was prepared through the reaction of esterification with methanol by using sulfuric acid catalyst to decrease Free Fatty Acid (FFA, and then transesterification reaction of refined RETRO was performed with methanol by using the alkaline catalyst. RETRO transesterification  reaction using potassium hidroxyde (KOH as catalyst with variation of 0.5 – 2,0 wt% of oil has been done at 65 °C. The biodiesel yield increased with the

  18. Ultrashort laser pulse cell manipulation using nano- and micro- materials

    Science.gov (United States)

    Schomaker, Markus; Killian, Doreen; Willenbrock, Saskia; Diebold, Eric; Mazur, Eric; Bintig, Willem; Ngezahayo, Anaclet; Nolte, Ingo; Murua Escobar, Hugo; Junghanß, Christian; Lubatschowski, Holger; Heisterkamp, Alexander

    2010-08-01

    The delivery of extra cellular molecules into cells is essential for cell manipulation. For this purpose genetic materials (DNA/RNA) or proteins have to overcome the impermeable cell membrane. To increase the delivery efficiency and cell viability of common methods different nano- and micro material based approaches were applied. To manipulate the cells, the membrane is in contact with the biocompatible material. Due to a field enhancement of the laser light at the material and the resulting effect the cell membrane gets perforated and extracellular molecules can diffuse into the cytoplasm. Membrane impermeable dyes, fluorescent labelled siRNA, as well as plasmid vectors encoded for GFP expression were used as an indicator for successful perforation or transfection, respectively. Dependent on the used material, perforation efficiencies over 90 % with a cell viability of about 80 % can be achieved. Additionally, we observed similar efficiencies for siRNA transfection. Due to the larger molecule size and the essential transport of the DNA into the nucleus cells are more difficult to transfect with GFP plasmid vectors. Proof of principle experiments show promising and adequate efficiencies by applying micro materials for plasmid vector transfection. For all methods a weakly focused fs laser beam is used to enable a high manipulation throughput for adherent and suspension cells. Furthermore, with these alternative optical manipulation methods it is possible to perforate the membrane of sensitive cell types such as primary and stem cells with a high viability.

  19. Stability of solid oxide fuel cell materials

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, T.R.; Pederson, L.R.; Stevenson, J.W.; Raney, P.E. [Pacific Northwest Lab., Richland, WA (United States)

    1995-08-01

    The phase stability and sintering behavior of materials used in SOFCs has been evaluated. The sintering behavior of Ca and Sr doped lanthanum. manganite (the preferred SOFC cathode material) is highly dependent on the relative proportion of A and B site cations in the material. Ca and Sr doped lanthanum chromite (the preferred interconnect material) have been shown to rapidly expand in reducing atmospheres at temperatures as low as 700{degrees}C. This expansion is due to the reduction of Cr{sup 4+} to Cr{sup 3+} in reducing environments.

  20. Chemistry and material science at the cell surface

    Directory of Open Access Journals (Sweden)

    Weian Zhao

    2010-04-01

    Full Text Available Cell surfaces are fertile ground for chemists and material scientists to manipulate or augment cell functions and phenotypes. This not only helps to answer basic biology questions but also has diagnostic and therapeutic applications. In this review, we summarize the most recent advances in the engineering of the cell surface. In particular, we focus on the potential applications of surface engineered cells for 1 targeting cells to desirable sites in cell therapy, 2 programming assembly of cells for tissue engineering, 3 bioimaging and sensing, and ultimately 4 manipulating cell biology.

  1. Dry storage cells for radioactive material

    International Nuclear Information System (INIS)

    A concrete cell structure for storing irradiated nuclear fuel or other highly active waste has air inlets in the roof and an outlet stack for effecting natural draught ventilation. Air flows through cells in heat exchange with nuclear fuel containers. The concrete cell structure is housed within a steel framed and sheeted weather tight building which provides a large air plenum for its inlet ports and thereby avoids serious pressure variations at these ports caused by wind loadings. (author)

  2. Materials for stem cell factories of the future

    Science.gov (United States)

    Celiz, Adam D.; Smith, James G. W.; Langer, Robert; Anderson, Daniel G.; Winkler, David A.; Barrett, David A.; Davies, Martyn C.; Young, Lorraine E.; Denning, Chris; Alexander, Morgan R.

    2014-06-01

    Polymeric substrates are being identified that could permit translation of human pluripotent stem cells from laboratory-based research to industrial-scale biomedicine. Well-defined materials are required to allow cell banking and to provide the raw material for reproducible differentiation into lineages for large-scale drug-screening programs and clinical use. Yet more than 1 billion cells for each patient are needed to replace losses during heart attack, multiple sclerosis and diabetes. Producing this number of cells is challenging, and a rethink of the current predominant cell-derived substrates is needed to provide technology that can be scaled to meet the needs of millions of patients a year. In this Review, we consider the role of materials discovery, an emerging area of materials chemistry that is in large part driven by the challenges posed by biologists to materials scientists.

  3. Device and materials modeling in PEM fuel cells

    CERN Document Server

    Promislow, Keith

    2009-01-01

    Device and Materials Modeling in PEM Fuel Cells is a specialized text that compiles the mathematical details and results of both device and materials modeling in a single volume. Proton exchange membrane (PEM) fuel cells will likely have an impact on our way of life similar to the integrated circuit. The potential applications range from the micron scale to large scale industrial production. Successful integration of PEM fuel cells into the mass market will require new materials and a deeper understanding of the balance required to maintain various operational states. This book contains articles from scientists who contribute to fuel cell models from both the materials and device perspectives. Topics such as catalyst layer performance and operation, reactor dynamics, macroscopic transport, and analytical models are covered under device modeling. Materials modeling include subjects relating to the membrane and the catalyst such as proton conduction, atomistic structural modeling, quantum molecular dynamics, an...

  4. Fuel cell electrode interconnect contact material encapsulation and method

    Energy Technology Data Exchange (ETDEWEB)

    Derose, Anthony J.; Haltiner, Jr., Karl J.; Gudyka, Russell A.; Bonadies, Joseph V.; Silvis, Thomas W.

    2016-05-31

    A fuel cell stack includes a plurality of fuel cell cassettes each including a fuel cell with an anode and a cathode. Each fuel cell cassette also includes an electrode interconnect adjacent to the anode or the cathode for providing electrical communication between an adjacent fuel cell cassette and the anode or the cathode. The interconnect includes a plurality of electrode interconnect protrusions defining a flow passage along the anode or the cathode for communicating oxidant or fuel to the anode or the cathode. An electrically conductive material is disposed between at least one of the electrode interconnect protrusions and the anode or the cathode in order to provide a stable electrical contact between the electrode interconnect and the anode or cathode. An encapsulating arrangement segregates the electrically conductive material from the flow passage thereby, preventing volatilization of the electrically conductive material in use of the fuel cell stack.

  5. Modern plastic solar cells: materials, mechanisms and modeling

    Directory of Open Access Journals (Sweden)

    Ryan C. Chiechi

    2013-07-01

    Full Text Available We provide a short review of modern ‘plastic’ solar cells, a broad topic that spans materials science, physics, and chemistry. The aim of this review is to provide a primer for non-experts or researchers in related fields who are curious about this rapidly growing field of interdisciplinary research. We introduce the basic concepts of plastic solar cells and design rules for maximizing their efficiency, including modern quantum chemical calculations that can aide in the design of new materials. We discuss the history of the materials and modern trends in polymeric donor materials and fullerene acceptors, and provide demonstrative data from hybrid polymer/quantum dot devices.

  6. Enhancing Solar Cell Efficiency Using Photon Upconversion Materials

    Directory of Open Access Journals (Sweden)

    Yunfei Shang

    2015-10-01

    Full Text Available Photovoltaic cells are able to convert sunlight into electricity, providing enough of the most abundant and cleanest energy to cover our energy needs. However, the efficiency of current photovoltaics is significantly impeded by the transmission loss of sub-band-gap photons. Photon upconversion is a promising route to circumvent this problem by converting these transmitted sub-band-gap photons into above-band-gap light, where solar cells typically have high quantum efficiency. Here, we summarize recent progress on varying types of efficient upconversion materials as well as their outstanding uses in a series of solar cells, including silicon solar cells (crystalline and amorphous, gallium arsenide (GaAs solar cells, dye-sensitized solar cells, and other types of solar cells. The challenge and prospect of upconversion materials for photovoltaic applications are also discussed

  7. Review on the application of nanostructure materials in solar cells

    Science.gov (United States)

    Afshar, Elham N.; Xosrovashvili, Georgi; Rouhi, Rasoul; Gorji, Nima E.

    2015-07-01

    In recent years, nanostructure materials have opened a promising route to future of the renewable sources, especially in the solar cells. This paper considers the advantages of nanostructure materials in improving the performance and stability of the solar cell structures. These structures have been employed for various performance/energy conversion enhancement strategies. Here, we have investigated four types of nanostructures applied in solar cells, where all of them are named as quantum solar cells. We have also discussed recent development of quantum dot nanoparticles and carbon nanotubes enabling quantum solar cells to be competitive with the conventional solar cells. Furthermore, the advantages, disadvantages and industrializing challenges of nanostructured solar cells have been investigated.

  8. Modern plastic solar cells: materials, mechanisms and modeling

    OpenAIRE

    Chiechi, Ryan C.; Havenith, Remco W.A.; Hummelen, Jan C.; L. Jan Anton Koster; Loi, Maria A.

    2013-01-01

    We provide a short review of modern ‘plastic’ solar cells, a broad topic that spans materials science, physics, and chemistry. The aim of this review is to provide a primer for non-experts or researchers in related fields who are curious about this rapidly growing field of interdisciplinary research. We introduce the basic concepts of plastic solar cells and design rules for maximizing their efficiency, including modern quantum chemical calculations that can aide in the design of new material...

  9. Pembuatan Dan Karakterisasi Bata Konstruksi Dengan Memanfaatkan Limbah Sludge Pertamina Pangkalan Susu

    OpenAIRE

    Novianti, Shinta

    2010-01-01

    The material of oil sludge in this research is the waste from PT. Pertamina Pangkalan Susu – Kab. Langkat. Oil sludge is a solid kind waste material from the side effect of oil exploration. This waste includes solid waste that has been dried and shaped lumps (oil sludge). The phisical chracteristic of the paving block sample that studied is density and water absorbtion, and mechanical characteristc is hardness, compressive strength and impact strength. The result of this research shows get t...

  10. Electrode materials for microbial fuel cells: nanomaterial approach

    KAUST Repository

    Mustakeem, Mustakeem

    2015-11-05

    Microbial fuel cell (MFC) technology has the potential to become a major renewable energy resource by degrading organic pollutants in wastewater. The performance of MFC directly depends on the kinetics of the electrode reactions within the fuel cell, with the performance of the electrodes heavily influenced by the materials they are made from. A wide range of materials have been tested to improve the performance of MFCs. In the past decade, carbon-based nanomaterials have emerged as promising materials for both anode and cathode construction. Composite materials have also shown to have the potential to become materials of choice for electrode manufacture. Various transition metal oxides have been investigated as alternatives to conventional expensive metals like platinum for oxygen reduction reaction. In this review, different carbon-based nanomaterials and composite materials are discussed for their potential use as MFC electrodes.

  11. Materials That Enhance Efficiency and Radiation Resistance of Solar Cells

    Science.gov (United States)

    Sun, Xiadong; Wang, Haorong

    2012-01-01

    A thin layer (approximately 10 microns) of a novel "transparent" fluorescent material is applied to existing solar cells or modules to effectively block and convert UV light, or other lower solar response waveband of solar radiation, to visible or IR light that can be more efficiently used by solar cells for additional photocurrent. Meanwhile, the layer of fluorescent coating material remains fully "transparent" to the visible and IR waveband of solar radiation, resulting in a net gain of solar cell efficiency. This innovation alters the effective solar spectral power distribution to which an existing cell gets exposed, and matches the maximum photovoltaic (PV) response of existing cells. By shifting a low PV response waveband (e.g., UV) of solar radiation to a high PV response waveband (e.g. Vis-Near IR) with novel fluorescent materials that are transparent to other solar-cell sensitive wavebands, electrical output from solar cells will be enhanced. This approach enhances the efficiency of solar cells by converting UV and high-energy particles in space that would otherwise be wasted to visible/IR light. This innovation is a generic technique that can be readily implemented to significantly increase efficiencies of both space and terrestrial solar cells, without incurring much cost, thus bringing a broad base of economical, social, and environmental benefits. The key to this approach is that the "fluorescent" material must be very efficient, and cannot block or attenuate the "desirable" and unconverted" waveband of solar radiation (e.g. Vis-NIR) from reaching the cells. Some nano-phosphors and novel organometallic complex materials have been identified that enhance the energy efficiency on some state-of-the-art commercial silicon and thin-film-based solar cells by over 6%.

  12. Pembuatan dan karakterisasi beton kedap suara dari serat tandan kosong kelapa sawit semen pc dan pasir

    OpenAIRE

    Gurning, Nuria

    2015-01-01

    The hollow bunch fiber of oil palm mixed with cement (PC) and sand can be used as a fiber concrete material. The fiber concrete that have been produced can be used as a relatively light-weight building material and can absorb the sound. The process making of the hollow bunch fiber of oil palm is washed with NaOH solution for 12 hours, dried and cut with a length of 20 cm. The fiber variation of 0, 2, 4, 6, 8, 10% (volume) was mixed with 350 gram of cement, 700 gram of particulate and aggregat...

  13. ANODE CATALYST MATERIALS FOR USE IN FUEL CELLS

    DEFF Research Database (Denmark)

    2002-01-01

    Catalyst materials having a surface comprising a composition M¿x?/Pt¿3?/Sub; wherein M is selected from the group of elements Fe, Co, Rh and Ir; or wherein M represent two different elements selected from the group comprising Fe, CO, Rh, Ir, Ni, Pd, CU, Ag, Au and Sn; and wherein Sub represents a...... substrate material selected from Ru and Os; the respective components being present within specific ranges, display improved properties for use inanodes for low-temperature fuel cell anodes for PENFC fuel cells and direct methanol fuel cells....

  14. PEM fuel cell bipolar plate material requirements for transportation applications

    Energy Technology Data Exchange (ETDEWEB)

    Borup, R.L.; Stroh, K.R.; Vanderborgh, N.E. [Los Alamos National Lab., NM (United States)] [and others

    1996-04-01

    Cost effective bipolar plates are currently under development to help make proton exchange membrane (PEM) fuel cells commercially viable. Bipolar plates separate individual cells of the fuel cell stack, and thus must supply strength, be electrically conductive, provide for thermal control of the fuel stack, be a non-porous materials separating hydrogen and oxygen feed streams, be corrosion resistant, provide gas distribution for the feed streams and meet fuel stack cost targets. Candidate materials include conductive polymers and metal plates with corrosion resistant coatings. Possible metals include aluminium, titanium, iron/stainless steel and nickel.

  15. Materials for Intermediate-Temperature Solid-Oxide Fuel Cells

    Science.gov (United States)

    Kilner, John A.; Burriel, Mónica

    2014-07-01

    Solid-oxide fuel cells are devices for the efficient conversion of chemical energy to electrical energy and heat. Research efforts are currently addressed toward the optimization of cells operating at temperatures in the region of 600°C, known as intermediate-temperature solid-oxide fuel cells, for which materials requirements are very stringent. In addition to the requirements of mechanical and chemical compatibility, the materials must show a high degree of oxide ion mobility and electrochemical activity at this low temperature. Here we mainly examine the criteria for the development of two key components of intermediate-temperature solid-oxide fuel cells: the electrolyte and the cathode. We limit the discussion to novel approaches to materials optimization and focus on the fluorite oxide for electrolytes, principally those based on ceria and zirconia, and on perovskites and perovskite-related families in the case of cathodes.

  16. SINTESIS DAN KARAKTERISASI SENYAWA OKSOTRINUKLIR [Cr3O(OOCC6H56(H2O3](NO3×nH2O

    Directory of Open Access Journals (Sweden)

    Aldes Lesbani

    2013-11-01

    Full Text Available Senyawa oksotrinuklir telah disintesis menggunakan kromium nitrat dan asam benzoat dalam etanol pada temperatur 80 oC selama 1 jam.Kristal senyawa oksotrinuklir hasil sintesis dikarakterisasi menggunakan spektrofotometer FTIR, 1H NMR padat, X-Ray Difraktometer, TGA, dan MS dengan teknik ionisasi dingin. Hasil penelitian menunjukkan bahwa senyawa oksotrinuklir mempunyai vibrasi yang khas pada bilangan gelombang 671 cm-1(ν Cr3-O. Identifikasi dengan spektrometer massa dalam asetonitril sebagai pelarut menunjukkan fragmentasi pada m/z: 1021.83 [Cr3O(OOCC6H56(MeCN3]+, 998,80 [Cr3O(OOCC6H56(MeCN2(H2O]+, 980,79 [Cr3O(OOCC6H56(MeCN2]+, 939,73 [Cr3O(OOCC6H56(MeCN]+. Puncak yang lebar dan besar pada spektrum 1H NMR menunjukkan bahwa kromium yang bersifat paramagnetic di dalam senyawa. Pola XRD menunjukkan bahwa senyawa oksotrinuklir adalah kristalin dan hasil termogravimetri menunjukkan senyawa oksotrinuklir stabil sampai suhu 174 oC dan mempunyai 5 mol air kristal. Dari hasil karakterisasi FTIR,1H NMR, XRD, TGA, dan MS dapat disimpulkan bahwa senyawa yang terbentuk adalah [Cr3O(OOCC6H56(H2O3](NO3×5H2O.

  17. Karakterisasi Simplisia Dan Uji Aktivitas Antibaktekteri Ekstrak Etanol Daun Tanaman Kecipir (Psophocarpus tetragonolobus (L.) DC.)

    OpenAIRE

    Putri, Rahmatika

    2012-01-01

    Wingbean is a group of nut plants that can be used as food staple, cattle food, traditional medicine, material of soil fertilizer and erotion prevention. Traditionally, wingbean leaf used for medicine of eye, ear and furunkel The leaf of this plant contain secondary metabolit. This research was done for the characterization of simplex and test of antibacterial activity ethanol extract wingbean leaf (Psophocarpus tetragonolobus (L.) DC.). The characterization of simplex include organilept...

  18. Molecular Design of Synthetic Biodegradable Polymers as Cell Scaffold Materials

    Institute of Scientific and Technical Information of China (English)

    WANG Shen-guo; WAN Yu-qing; CAI Qing; HE Bin; CHEN Wen-na

    2004-01-01

    Poly(lactic acid) and its copolymers are regarded as the most useful biomaterials. The good biocompatibility, biodegradability and mechanical properties of them make the synthetic biodegradable polymers have primary application to tissue engineering. The advantages and disadvantages of the synthetic biodegradable polymers as cell scaffold materials are evaluated. This article reviews the modification of polylactide-family aliphatic polymers to improve the cell affinity when the polymers are used as cell scaffolds. We have developed four main approaches: to modify polyester cell scaffolds in combination of plasma treating and collagen coating; to introduce hydrophilic segments into aliphatic polyester backbones; to introduce pendant functional groups into polyester chains; to modify polyester with dextran. The results of the cell cultures prove that the approaches mentioned above have improved the cell affinity of the polyesters and have modulated cell function such as adhesion, proliferation and migration.

  19. LEO effects on candidate solar-cell cover materials

    International Nuclear Information System (INIS)

    The Long Duration Exposure Facility (LDEF) test samples discussed within are part of the Solar Array Materials Passive (SAMPLE) LDEF experiment, which included contributions from NASA and Jet Propulsion Lab (JPL). Only the JPL portion is described in this paper. The JPL test plate contains 30 individual thin silicon solar cell/cover samples. It was the intent of the experiment to evaluate the stability and protective capability of various cover materials such as conventional fused silica and potential alternative materials such as Teflon, silicone RTV's, glass resins, polyimides, and a copolymer encapsulate. Examination of the recovered experiment shows extensive physical changes have occurred. Approximately 150 micrometeoroid/debris impact were noted, some directly on the solar cells. Of particular interest are the results of ultraviolet and atomic oxygen interactions with the various cover materials. Initial results show that the fused silica cover is the most stable and protective, with performance of other materials varying widely. Electrical measurements of the cell/cover samples are presented as part of the evaluation of cover materials to protect cells in low earth orbit environments

  20. Degradation of elastomeric gasket materials in PEM fuel cells

    International Nuclear Information System (INIS)

    Polymer electrolyte membrane (PEM) fuel cell stack requires gaskets in each cell to keep the reactant gases within their respective regions. Long-term durability of the fuel cell stacks depends heavily on the functionality of the gaskets. Both the leachants from the seal materials and the cracking of the seals are of great concern to the overall durability of the fuel cell stacks. The degradation of four commercially available gasket materials was investigated in a PEM fuel cell environment in this study. Optical microscopy reveals that the degradation starts with surface roughness from the early stage of exposure and finally results in cracks over time. Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) were employed to study the surface chemistry of the gasket materials before and after exposure to the PEM fuel cell environment over time. Results from these analyses indicate that the surface chemistry changed initially as a manifestation of the chemical degradation and proceeded via de-cross-linking and chain scission in the backbone. Atomic adsorption spectrometry analysis was used to identify the leachants in the soaking solution from the gasket materials. The effect due to applied stress is reported as well

  1. Karakterisasi Tepung Kasava Yang Dimodifikasi Dengan Bakteri Selulolitik Sebagai Bahan Baku Produk Mie Dan Biskuit

    OpenAIRE

    Sembiring, Simon Petrus

    2011-01-01

    The research was conducted to dertermine the characterization of modified starch cassava with cellulolytic bacteria as the raw materials of noodles and biscuits products. The study was conducted using single-factor randomized block design that is the number of cellulolytic bacteria (J) with 5 degree (J1:0 ml, J2:10 ml, J3:20 ml, J4:30 ml, J5:40 ml) and for the ratio of wheat with flour cassava flour(100:0, 90:10, 80:20, 70:30, 60:40). Product was parameters for the flour were the chemical pro...

  2. Investigations on quinquethiophenes as donor materials in organic solar cells

    International Nuclear Information System (INIS)

    Organic photovoltaics could in the future represent a possibility for energy production from renewable energy sources. The advance consists here first of all in the potential of a very reasonable fabrication, for instance a production in the role-to-role procedurre, which can be prusued so on flexible substrates like for instance foils. Although the material costs are low, until the commercialization of organic solar cells among others an increasement of their power efficiency is necessary. Preferably in organic solar cells donor and acceptor materials should be applied, the absorption spectra and energy levels of which are ideally matched, because so can high zero-current voltages be reached. Additionally high absorption coefficents of the materials over a large spectral range can lead to high current densities in these photovoltaic components. In this thesis novel quinquethiophenes as donors in organic solar cells are studied, which consist as basic unit of five thiophene rings as well as dicyanovinyl end groups and alkyl side chains. The studied materials possess a high absorption coefficient and reach because of the high ionization potential high zero-current voltages in organic solar cells under application of the fullerenet C60 as acceptor. Simultaneously a efficient separation of the excitons on the acceptor-donor interface occurs. However the high ionization potential of the quinquethiophenes puts special requirements to the further solar-cell structure. Within this thesis it is shown that adifference between internal voltage and zero-current voltage influences decidingly the shape of the solar-cell characteristic and can generate a S-shape in the neighbourhood of the zero-current voltage. The internal voltage is hereby determined by the contacting of the photoactive layers. An increasement of the internal voltage of the solar cell can be reached by a corresponding material choice. So in this thesis it is shown that organic solar cells based on these

  3. Amorphous silicon materials and solar cells - Progress and directions

    Science.gov (United States)

    Sabisky, E.; Mahan, H.; McMahon, T.

    In 1978, the U.S. Department of Energy initiated government sponsored research in amorphous materials and thin film solar cells. The program was subsequently transferred to the Solar Energy Research Institute for program management. The program grew into a major program for the development of high efficiency (greater than 10 percent), cost effective (15-40 cents per peak watt) thin film amorphous solar cells. The present international interest, the substantial progress made in the device area (2 percent PIN cell in 1976 to 10 percent PIN cell in 1982), and the marketing of the first consumer products using thin film solar cells are to a large ducts using thin film solar cells are to a large extent a consequence of this goal-oriented program.

  4. Improved Membrane Materials for PEM Fuel Cell Application

    Energy Technology Data Exchange (ETDEWEB)

    Kenneth A. Mauritz; Robert B. Moore

    2008-06-30

    The overall goal of this project is to collect and integrate critical structure/property information in order to develop methods that lead to significant improvements in the durability and performance of polymer electrolyte membrane fuel cell (PEMFC) materials. This project is focused on the fundamental improvement of PEMFC membrane materials with respect to chemical, mechanical and morphological durability as well as the development of new inorganically-modified membranes.

  5. Material and solar cell research in microcrystalline silicon

    OpenAIRE

    Shah, Arvind; Meier, Johannes; Vallat-Sauvain, Evelyne; Wyrsch, Nicolas; Kroll, U.; Droz, C.; U. Graf

    2008-01-01

    This contribution describes the introduction of hydrogenated microcrystalline silicon (μc-Si:H) as novel absorber material for thin-film silicon solar cells. Work done at IMT Neuchâtel in connection with deposition of μc-Si:H layers by very high frequency glow discharge deposition is related in detail. Corresponding layer properties w.r.t. material microstructure, hydrogen content, stability and electronic transport are referred to. Basic properties of single-junction, entirely microcrystalli...

  6. Alternative materials for crystalline silicon solar cells - Risks and implications

    OpenAIRE

    Kwapil, Wolfram

    2010-01-01

    This thesis considers the use of alternative silicon materials for photovoltaics – often termed “upgraded metallurgical grade” silicon – from different angles and evaluates the risks and implications for the wafer and solar cell properties at selected steps along the entire process chain.The properties of the alternative, upgraded metallurgical grade silicon materials analyzed in the course of this thesis were governed by the simultaneous presence of boron and phosphorus in high concentration...

  7. Materials Science Constraints on the Development of Aluminium Reduction Cells

    Science.gov (United States)

    Metson, James; McIntosh, Grant; Etzion, Ronny

    The Hall-Heroult process for the production of Aluminium metal is some 125 years old. The process is energy constrained by the need to shed around half of the (electrical) energy supplied to the cell as waste heat. The molten cryolite electrolyte is sufficiently aggressive that the only reliable method of protecting the side wall of the cell is to maintain a frozen layer of electrolyte at the hot face of the sidewall. Thus the lack of a cryolite resistant sidewall is but one of several materials science constraints which still limit the energy efficiency of the process. An inert anode and non-consumable cathode are also significant challenges which limit cell life and energy efficiency. Thus there are major challenges in both materials development and new conceptual cell designs to improve the efficiency of this process.

  8. Direct alcohol fuel cells materials, performance, durability and applications

    CERN Document Server

    Corti, Horacio R

    2013-01-01

    Direct Alcohol Fuel Cells: Materials, Performance, Durability and Applications begins with an introductory overview of direct alcohol fuel cells (DAFC); it focuses on the main goals and challenges in the areas of materials development, performance, and commercialization. The preparation and the properties of the anodic catalysts used for the oxidation of methanol, higher alcohols, and alcohol tolerant cathodes are then described. The membranes used as proton conductors in DAFC are examined, as well as alkaline membranes, focusing on the electrical conductivity and alcohol permeability. The use

  9. Functional living biointerfaces to direct cell-material interaction

    OpenAIRE

    Rodrigo Navarro, Aleixandre

    2015-01-01

    [EN] This thesis deals with the development of a living biointerface between synthetic substrates and living cells to engineer cell-material interactions for tissue engineering purposes. This living biointerface is made of Lactococcus lactis, a non-pathogenic lactic bacteria widely used as starter in the dairy industry and, recently, in the expression of heterologous proteins in applications such as oral vaccine delivery or membrane-bound expression of proteins. L. lactis has been engine...

  10. Electron Acceptor Materials Engineering in Colloidal Quantum Dot Solar Cells

    KAUST Repository

    Liu, Huan

    2011-07-15

    Lead sulfide colloidal quantum dot (CQD) solar cells with a solar power conversion efficiency of 5.6% are reported. The result is achieved through careful optimization of the titanium dioxide electrode that serves as the electron acceptor. Metal-ion-doped sol-gel-derived titanium dioxide electrodes produce a tunable-bandedge, well-passivated materials platform for CQD solar cell optimization. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Cellular interaction between fixed and living cells; transfer of radioactive materials from living cells to fixed cells

    Energy Technology Data Exchange (ETDEWEB)

    Sakiyama, H.; Otsu, H.; Kanegasaki, S.

    1979-06-01

    Transfer of radioactive materials to fixed cells from an overlying layer of living cells has been examined to determine whether fixed cells can act as acceptors of glycosyltransferases of living cells. After the incubation of living cells were removed by EDTA treatment, and the radioactivity associated with the fixed cells was determined. Lipids, proteins and carbohydrates were found to be transfered from the living cells to the fixed cells. The amount of radioactivity transferred to the fixed cells was dependent on the number of both fixed and living cells and increased with the time of incubation. When fixed cells were treated with chloroform-methanol before the addition of living cells, the transfer of both lipids and proteins to the fixed cells decreased drastically, but only a slight decrease in carbohydrate transfer was observed. Most of the radioactive materials transferred from living cells labeled with glucosamine or fucose to chloroform-methanol-treated fixed cells were solubilized by trypsin but not by the detergents tested. Approximately 55% of the materials transferred from the cells labeled with glucosamine could be solubilized by hyaluronidase and chondroitinase, and the rest was solubilized by neuraminidase and a glycosidase mixture. The treatment of chloroform-methanol-extracted fixed cells with trypsin caused a significant decrease in the transfer from cells labeled with glucosamine. When nucleotide sugars were used as the radioactive precursor, no significant amount of radioactivity was transferred to the fixed cells.

  12. Material properties of microcrystalline silicon for solar cell application

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Czang-Ho; Shin, Myunghun; Lim, Mi-Hwa; Seo, Jun-Yong; Lee, Jung-Eun; Lee, Hee-Yong; Kim, Byoung-June; Choi, Donguk [Development Group, LCD Division, Samsung Electronics, Yongin City, Gyeonggi-do (Korea, Republic of)

    2011-01-15

    The paper reviews the material requirements of microcrystalline silicon ({mu}c-Si) in terms of the device operation and configuration for thin film solar cells and thin film transistors (TFTs). We investigated the material properties of {mu}c-Si films deposited by using 13.56 MHz plasma-enhanced chemical vapor deposition (PECVD) from a conventional H{sub 2} dilution in SiH{sub 4}. Two types of intrinsic {mu}c-Si films deposited at the high pressure narrow electrode gap and the low pressure wide electrode gap were studied for the solar cell absorption layers. The material properties were characterized using dark conductivity, Raman spectroscopy, and transmission electron microscope (TEM) measurements. The {mu}c-Si quality and solar cell performance were mainly determined by microstructure characteristics. Solar cells adopting the optimized {mu}c-Si film demonstrated high stability with no significant changes in solar cell performance after air exposure for six months and subsequent illumination for over 300 h. The results can be explained that low ion bombardment and high atomic hydrogen density under the PECVD condition of the high pressure narrow electrode gap produce high-quality {mu}c-Si films for solar cell application. (author)

  13. Photoconversion of organic materials into single-cell protein

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, P.F.

    1991-12-31

    A process is described for converting organic materials (such as biomass wastes) into sterile, high-grade bacterial protein suitable for use an animal feed or human food supplements. In a preferred embodiment the process involves thermally gasifying the organic material into primarily carbon monoxide, hydrogen and nitrogen products, followed by photosynthetic bacterial assimilation of the gases into cell material, which can be high as 65% protein. The process is ideally suited for waste recycling and for food production under zero-gravity or extra-terrestrial conditions.

  14. Cell-based composite materials with programmed structures and functions

    Energy Technology Data Exchange (ETDEWEB)

    None

    2016-03-01

    The present invention is directed to the use of silicic acid to transform biological materials, including cellular architecture into inorganic materials to provide biocomposites (nanomaterials) with stabilized structure and function. In the present invention, there has been discovered a means to stabilize the structure and function of biological materials, including cells, biomolecules, peptides, proteins (especially including enzymes), lipids, lipid vesicles, polysaccharides, cytoskeletal filaments, tissue and organs with silicic acid such that these materials may be used as biocomposites. In many instances, these materials retain their original biological activity and may be used in harsh conditions which would otherwise destroy the integrity of the biological material. In certain instances, these biomaterials may be storage stable for long periods of time and reconstituted after storage to return the biological material back to its original form. In addition, by exposing an entire cell to form CSCs, the CSCs may function to provide a unique system to study enzymes or a cascade of enzymes which are otherwise unavailable.

  15. Graphene-Based Materials for Stem Cell Applications

    Directory of Open Access Journals (Sweden)

    Tae-Hyung Kim

    2015-12-01

    Full Text Available Although graphene and its derivatives have been proven to be suitable for several biomedical applications such as for cancer therapy and biosensing, the use of graphene for stem cell research is a relatively new area that has only recently started to be investigated. For stem cell applications, graphene has been utilized by itself or in combination with other types of materials such as nanoparticles, nanofibers, and polymer scaffolds to take advantage of the several unique properties of graphene, such as the flexibility in size, shape, hydrophilicity, as well as its excellent biocompatibility. In this review, we will highlight a number of previous studies that have investigated the potential of graphene or its derivatives for stem cell applications, with a particular focus on guiding stem cell differentiation into specific lineages (e.g., osteogenesis, neurogenesis, and oligodendrogenesis, promoting stem cell growth, stem cell delivery/transplantation, and effective monitoring of their differentiation. We hope that this review promotes and accelerates the use of graphene-based materials for regenerative therapies, especially for stem cell-based approaches to cure various incurable diseases/disorders such as neurological diseases (e.g., Alzheimer’s disease and Parkinson’s disease, stroke, spinal cord injuries, bone/cartilage defects, and cardiovascular diseases.

  16. Advanced materials and processes for polymer solar cell devices

    DEFF Research Database (Denmark)

    Petersen, Martin Helgesen; Søndergaard, Roar; Krebs, Frederik C

    2010-01-01

    The rapidly expanding field of polymer and organic solar cells is reviewed in the context of materials, processes and devices that significantly deviate from the standard approach which involves rigid glass substrates, indium-tin-oxide electrodes, spincoated layers of conjugated polymer...

  17. Modern plastic solar cells : materials, mechanisms and modeling

    NARCIS (Netherlands)

    Chiechi, Ryan C.; Havenith, Remco W.A.; Hummelen, Jan C.; Koster, L. Jan Anton; Loi, Maria A.

    2013-01-01

    We provide a short review of modern 'plastic' solar cells, a broad topic that spans materials science, physics, and chemistry. The aim of this review is to provide a primer for non-experts or researchers in related fields who are curious about this rapidly growing field of interdisciplinary research

  18. Materials selection for solid oxide fuel cells (SOFCs) systems

    International Nuclear Information System (INIS)

    Because fuel cells, as electrochemical devices, convert fuels such as hydrogen into electricity without combustion they create virtually no pollution and hold the key to future prosperity and a healthy global environment. In recent years, the development and commercialisation of fuel cells systems for different applications is increasing tremendously. A discussion in made, in this paper, upon the benefits obtained from the few potential applications and the future of such devices with a particular, attention being given to design (and operation of Solid Oxide Fuel Cells (SOFCs), nothing the restrictions based on materials requirements and fuel specifications. The materials selection for this kind of fuel cells is very difficult due to the temperature range they operate in. The advantage and limitations, development state, and technical issues for novel materials used in SOFC electrodes, electrolyte and interconnect, that are the subject of a majority of contemporary research, and their properties are reviewed and discussed. A complete scenario is proposed as a competitive energy policy and a step forward to the target of sustainable development. It is emphasised that fuel cells will be a significant contributor within a portfolio of energy sources in the coming 10 to 20 years.(Author)

  19. SINTESIS DAN KARAKTERISASI BIODIESEL DARI MINYAK KEMIRI SUNAN (Reutealis trisperma DENGAN VARIASI KONSENTRASI KATALIS NAOH

    Directory of Open Access Journals (Sweden)

    Holilah -

    2014-06-01

    Full Text Available Sintesis biodiesel dari minyak Kemiri Sunan (Reutealis trisperma (RTO menggunakan NaOH sebagai katalis dengan variasi konsentrasi katalis yaitu 0,5; 1,0; 1,5 dan 2,0 wt% telah diteliti. Minyak kemiri sunan (Reutealis trisperma adalah bahan baku yang menarik untuk produksi biodiesel. Biodiesel disintesis dengan dua tahap reaksi yaitu esterifikasi menggunakan katalis H2SO4 dan transesterifikasi dengan menggunakan katalis NaOH. Dalam penelitian ini, diteliti pengaruh konsentrasi katalis terhadap produk biodisel serta dan karakteristiknya. Hasil penelitian menunjukkan bahwa yield biodiesel meningkat seiring dengan meningkatnya konsentrasi katalis dari 0,5-1,0 wt%, selanjutnya dengan meningkatnya konsentrasi katalis dari 1,5-2,0 wt% membuat yield menurun. Yield optimum dicapai pada 84,7%. FAME (fatty  acid  methyl  ester diperoleh dengan konsentrasi katalis 1 wt% pada kondisi reaksi 65°C, waktu reaksi 1 jam dan rasio metanol minyak 1:2 (wt/wt. Karakteristik biodiesel diamati dengan uji standart bahan bakar dan hasilnya dibandingkan dengan standart ASTM D6751-02. Karakteristik biodiesel yang disintesis dengan konsentrasi katalis NaOH 1% adalah angka asam (0,55 mg KOH/g, densitas (0,90 gr/cm3, viskositas pada 40°C (9,2 cSt, angka setana (54,5 dan residu karbon (0,24 wt%/wt. This research was investigated bio diesel synthesis of Reutealis trisperma oil (RTO by using NaOH as a catalist with variation of catalyst concentration as follow 0.5; 1.0; 1.5 and 2,0 wt% . Reutealis trisperma oil is an attractive raw material for  bio diesel production. It was produced by two steps of reactions, they are esterification by using H2SO4 catalyst and transesterification by using NaOH catalyst. This study examined the effect of catalyst concentration on the yield of biodiesel and their selected properties. The result showed, that the bio diesel yield  with catalyst concentration increasing from 0,5-1,0 wt%, increased, while increasing the concentration from 1

  20. Studying the effect of material parameters on cell performance of tubular-shaped PEM fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Al-Baghdadi, Maher A.R. Sadiq [Department of Mechanical Engineering, International Technological University, 115 Dollis Hill Lane, London NW2 6HS (United Kingdom)

    2008-11-15

    A full three-dimensional, non-isothermal computational fluid dynamics model of a tubular-shaped proton exchange membrane (PEM) fuel cell has been developed. This comprehensive model accounts for the major transport phenomena in a PEM fuel cell: convective and diffusive heat and mass transfer, electrode kinetics, transport and phase change mechanism of water, and potential fields. The model is shown to be able to understand the many interacting, complex electrochemical, and transport phenomena that cannot be studied experimentally. In addition to the new feature of tubular-shaped geometry of PEM fuel cell, this model is used to study the effects of several material parameters on fuel cell performance. Detailed analyses of the temperature distribution inside the tubular cell under various material properties have been conducted and examined. The analysis helped identifying critical parameters and shed insight into the physical mechanisms leading to a fuel cell performance and durability under various material conditions. (author)

  1. Studying the effect of material parameters on cell performance of tubular-shaped PEM fuel cell

    International Nuclear Information System (INIS)

    A full three-dimensional, non-isothermal computational fluid dynamics model of a tubular-shaped proton exchange membrane (PEM) fuel cell has been developed. This comprehensive model accounts for the major transport phenomena in a PEM fuel cell: convective and diffusive heat and mass transfer, electrode kinetics, transport and phase change mechanism of water, and potential fields. The model is shown to be able to understand the many interacting, complex electrochemical, and transport phenomena that cannot be studied experimentally. In addition to the new feature of tubular-shaped geometry of PEM fuel cell, this model is used to study the effects of several material parameters on fuel cell performance. Detailed analyses of the temperature distribution inside the tubular cell under various material properties have been conducted and examined. The analysis helped identifying critical parameters and shed insight into the physical mechanisms leading to a fuel cell performance and durability under various material conditions

  2. Graphene as a Material for Solar Cells Applications

    Directory of Open Access Journals (Sweden)

    Czerniak-Reczulska M.

    2015-12-01

    Full Text Available Graphene is a two-dimensional material with honeycomb structure. Its unique mechanical, physical electrical and optical properties makes it an important industrially and economically material in the coming years. One of the application areas for graphene is the photovoltaic industry. Studies have shown that doped graphene can change one absorbed photon of a few electrons, which in practice means an increase in efficiency of solar panels. In addition, graphene has a low coefficient of light absorption 2.3% which indicates that is an almost completely transparent material. In fact, it means that solar cells based on graphene can significantly expand the absorbed spectrum wavelengths of electromagnetic radiation. Graphene additionally is a material with a very high tensile strength so it can be successfully used on the silicon, flexible and organic substrates as well. So far, significant effort has been devoted to using graphene for improving the overall performance of photovoltaic devices. It has been reported that graphene can play diverse, but positive roles such as an electrode, an active layer, an interfacial layer and an electron acceptor in photovoltaic cells. Research on solar cells containing in its structure graphene however, are still at laboratory scale. This is due to both lack the ability to produce large-sized graphene and reproducibility of its parameters

  3. Novel materials for stable perovskite solar cells (Presentation Recording)

    Science.gov (United States)

    Abate, Antonio

    2015-09-01

    Organic-inorganic perovskites are quickly overrunning research activities in new materials for cost-effective and high-efficiency photovoltaic technologies. Since the first demonstration from Kojima and co-workers in 2009, several perovskite-based solar cells have been reported and certified with rapidly improving power conversion efficiency. Recent reports demonstrate that perovskites can compete with the most efficient inorganic materials, while they still allow processing from solution as potential advantage to deliver a cost-effective solar technology. Compare to the impressive progress in power conversion efficiency, stability studies are rather poor and often controversial. An intrinsic complication comes from the fact that the stability of perovskite solar cells is strongly affected by any small difference in the device architecture, preparation procedure, materials composition and testing procedure. In the present talk we will focus on the stability of perovskite solar cells in working condition. We will discuss a measuring protocol to extract reliable and reproducible ageing data. We will present new materials and preparation procedures which improve the device lifetime without giving up on high power conversion efficiency.

  4. A Novel Approach for Introducing Bio-Materials Into Cells

    International Nuclear Information System (INIS)

    A novel approach was developed to introduce biological materials into cells for gene transfection and gene therapy applications. The method is based on the technique of electrospraying bio-materials into cells. A prototype apparatus was constructed for a feasibility study. The features of the gene transfector include: (1) A dual-capillary assembly to spray suspensions of biological materials. The outer capillary provided sheathing liquid that controlled the charge level on individual particles without altering the properties of suspensions. (2) An air-CO2 gas mixture was used for suppressing possible corona discharge and kept the same gas composition as those in incubators. (3) The designed chamber enabled the spray to operate at reduced pressure for increasing sprayed particle velocity. In the feasibility study, both suspensions of plasmid and plasmid-coated gold particles were used. The plasmid used was the commercially available Enhanced Green Fluorescent Protein gene. COS-1 cells were used as the target and the liquid media was evacuated immediately prior to the spraying process. Electrospraying was conducted at ambient pressure and the duration was no more than 2 min. After the spray transfection, the media was immediately replaced and the cell samples were returned to the incubator for 36 h. Transgene expression was detected by cellular fluorescence. This technology promises to have great potential for gene transfection and therapy studies

  5. Advanced proton-exchange materials for energy efficient fuel cells.

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto, Cy H.; Grest, Gary Stephen; Hickner, Michael A.; Cornelius, Christopher James; Staiger, Chad Lynn; Hibbs, Michael R.

    2005-12-01

    The ''Advanced Proton-Exchange Materials for Energy Efficient Fuel Cells'' Laboratory Directed Research and Development (LDRD) project began in October 2002 and ended in September 2005. This LDRD was funded by the Energy Efficiency and Renewable Energy strategic business unit. The purpose of this LDRD was to initiate the fundamental research necessary for the development of a novel proton-exchange membranes (PEM) to overcome the material and performance limitations of the ''state of the art'' Nafion that is used in both hydrogen and methanol fuel cells. An atomistic modeling effort was added to this LDRD in order to establish a frame work between predicted morphology and observed PEM morphology in order to relate it to fuel cell performance. Significant progress was made in the area of PEM material design, development, and demonstration during this LDRD. A fundamental understanding involving the role of the structure of the PEM material as a function of sulfonic acid content, polymer topology, chemical composition, molecular weight, and electrode electrolyte ink development was demonstrated during this LDRD. PEM materials based upon random and block polyimides, polybenzimidazoles, and polyphenylenes were created and evaluated for improvements in proton conductivity, reduced swelling, reduced O{sub 2} and H{sub 2} permeability, and increased thermal stability. Results from this work reveal that the family of polyphenylenes potentially solves several technical challenges associated with obtaining a high temperature PEM membrane. Fuel cell relevant properties such as high proton conductivity (>120 mS/cm), good thermal stability, and mechanical robustness were demonstrated during this LDRD. This report summarizes the technical accomplishments and results of this LDRD.

  6. Tungsten materials as durable catalyst supports for fuel cell electrodes

    Science.gov (United States)

    Perchthaler, M.; Ossiander, T.; Juhart, V.; Mitzel, J.; Heinzl, C.; Scheu, C.; Hacker, V.

    2013-12-01

    Durable platinum catalyst support materials, e.g. tungsten carbide (WC), tungsten oxide (WOx) and self-synthesized tungsten oxide (WOxs) were evaluated for the use in High-Temperature Proton Exchange Fuel Cells (HT-PEM) based on phosphoric acid doped polybenzimidazole as electrolyte. The support materials and the catalyst loaded support materials were characterized ex-situ by cyclic voltammetry in HClO4, potential cycling, CO-stripping, electron microscopy and X-ray diffraction measurements. The tungsten oxide and tungsten carbide based supported catalysts were compared to High Surface Area Carbon (HSAC), each coated with platinum via the same in-house manufacturing procedures. The in-house manufacturing procedures resulted in catalyst particle sizes on HSAC of 3-4 nm with a uniform distribution. The in-situ Potential Cycling experiments of WOx or WOxs supported catalysts showed much lower degradation rates compared to High Surface Area Carbons. The formation of WOx species on WC was proven by ex- and in-situ cyclic voltammetric studies and thermogravimetric analyses. X-ray diffraction, ex-situ cyclic voltammetry and in-situ cyclic voltammetry showed that WOx is formed from WC as starting material under oxidizing conditions. Finally a 1000 h durability test with WOx as catalyst support material on the anode was done in a HT-PEM fuel cell with reformed methanol on the anode.

  7. Polymeric materials for photoelectrochemical cells for hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Abdel-Aal, H.K. (King Fahd Univ. of Petroleum and Minerals, Dhahran (SA). Dept. of Chemical Engineering); Hassan, H.H. (Cairo Univ. (Egypt). Dept. of Physics); Mohamed, M.A.; Khairy, S.A. (National Research Center, Cairo (EG). Dept. of Solar Energy)

    1991-01-01

    Some filled-polymeric materials were selected and the properties of their electrical conduction were examined in order to investigate the possibility of using them as semiconductor electrodes for hydrogen production in photoelectrochemical cells (PEC). The activation energy and the corresponding wavelength are calculated for the polymeric materials proposed in the study. As a result, mixtures of butadiene acrylo-nitrile rubber (BNR) and polychloroprene (PCP) to which ZnO is added, proved to be potential candidates for making semiconductor electrodes for PEC used in hydrogen production. (Author).

  8. High-Efficiency Solar Cells Using Photonic-Bandgap Materials

    Science.gov (United States)

    Dowling, Jonathan; Lee, Hwang

    2005-01-01

    Solar photovoltaic cells would be designed to exploit photonic-bandgap (PBG) materials to enhance their energy-conversion efficiencies, according to a proposal. Whereas the energy-conversion efficiencies of currently available solar cells are typically less than 30 percent, it has been estimated that the energy-conversion efficiencies of the proposed cells could be about 50 percent or possibly even greater. The primary source of inefficiency of a currently available solar cell is the mismatch between the narrow wavelength band associated with the semiconductor energy gap (the bandgap) and the broad wavelength band of solar radiation. This mismatch results in loss of power from both (1) long-wavelength photons, defined here as photons that do not have enough energy to excite electron-hole pairs across the bandgap, and (2) short-wavelength photons, defined here as photons that excite electron- hole pairs with energies much above the bandgap. It follows that a large increase in efficiency could be obtained if a large portion of the incident solar energy could be funneled into a narrow wavelength band corresponding to the bandgap. In the proposed approach, such funneling would be effected by use of PBG materials as intermediaries between the Sun and photovoltaic cells.

  9. Simulation of perovskite solar cells with inorganic hole transporting materials

    DEFF Research Database (Denmark)

    Wang, Yan; Xia, Zhonggao; Liu, Yiming;

    2015-01-01

    improvement in power conversion efficiency (PCE). Here, we investigated the effect of band offset between inorganic HTM/absorber layers. The solar cell simulation program adopted in this work is named wxAMPS, an updated version of the AMPS tool (Analysis of Microelectronic and Photonic Structure).......Device modeling organolead halide perovskite solar cells with planar architecture based on inorganic hole transporting materials (HTMs) were performed. A thorough understanding of the role of the inorganic HTMs and the effect of band offset between HTM/absorber layers is indispensable for further...

  10. Functional Materials for Dye-sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    S.V. Raksha

    2015-12-01

    Full Text Available A review on the analysis of characteristics of dye-sensitized solar cells (DSSC is provided. DSSC design, materials that are used for the manufacture of functional layers and the characteristics of elements depending on their properties are analyzed. The basic disadvantages DSSC, the factors leading to their appearance, as well as solutions to eliminate or reduce the impact of these factors are revealed.

  11. Durability and performance optimization of cathode materials for fuel cells

    Science.gov (United States)

    Colon-Mercado, Hector Rafael

    The primary objective of this dissertation is to develop an accelerated durability test (ADT) for the evaluation of cathode materials for fuel cells. The work has been divided in two main categories, namely high temperature fuel cells with emphasis on the Molten Carbonate Fuel Cell (MCFC) cathode current collector corrosion problems and low temperature fuel cells in particular Polymer Electrolyte Fuel Cell (PEMFC) cathode catalyst corrosion. The high operating temperature of MCFC has given it benefits over other fuel cells. These include higher efficiencies (>50%), faster electrode kinetics, etc. At 650°C, the theoretical open circuit voltage is established, providing low electrode overpotentials without requiring any noble metal catalysts and permitting high electrochemical efficiency. The waste heat is generated at sufficiently high temperatures to make it useful as a co-product. However, in order to commercialize the MCFC, a lifetime of 40,000 hours of operation must be achieved. The major limiting factor in the MCFC is the corrosion of cathode materials, which include cathode electrode and cathode current collector. In the first part of this dissertation the corrosion characteristics of bare, heat-treated and cobalt coated titanium alloys were studied using an ADT and compared with that of state of the art current collector material, SS 316. PEMFCs are the best choice for a wide range of portable, stationary and automotive applications because of their high power density and relatively low-temperature operation. However, a major impediment in the commercialization of the fuel cell technology is the cost involved due to the large amount of platinum electrocatalyst used in the cathode catalyst. In an effort to increase the power and decrease the cathode cost in polymer electrolyte fuel cell (PEMFC) systems, Pt-alloy catalysts were developed to increase its activity and stability. Extensive research has been conducted in the area of new alloy development and

  12. Nano-structured electron transporting materials for perovskite solar cells

    Science.gov (United States)

    Liu, Hefei; Huang, Ziru; Wei, Shiyuan; Zheng, Lingling; Xiao, Lixin; Gong, Qihuang

    2016-03-01

    Organic-inorganic hybrid perovskite solar cells have been developing rapidly in the past several years, and their power conversion efficiency has reached over 20%, nearing that of polycrystalline silicon solar cells. Because the diffusion length of the hole in perovskites is longer than that of the electron, the performance of the device can be improved by using an electron transporting layer, e.g., TiO2, ZnO and TiO2/Al2O3. Nano-structured electron transporting materials facilitate not only electron collection but also morphology control of the perovskites. The properties, morphology and preparation methods of perovskites are reviewed in the present article. A comprehensive understanding of the relationship between the structure and property will benefit the precise control of the electron transporting process and thus further improve the performance of perovskite solar cells.

  13. Disordered, strongly scattering porous materials as miniature multipass gas cells

    CERN Document Server

    Svensson, Tomas; Lewander, Märta; Xu, Can T; Svanberg, Sune

    2010-01-01

    Spectroscopic gas sensing is both a commercial success and a rapidly advancing scientific field. Throughout the years, massive efforts have been directed towards improving detection limits by achieving long interaction pathlengths. Prominent examples include the use of conventional multipass gas cells, sophisticated high-finesse cavities, gas-filled holey fibers, integrating spheres, and diffusive reflectors. Despite this rich flora of approaches, there is a continuous struggle to reduce size, gas volume, cost and alignment complexity. Here, we show that extreme light scattering in porous materials can be used to realise miniature gas cells. Near-infrared transmission through a 7 mm zirconia (ZrO2) sample with a 49% porosity and subwavelength pore structure (on the order of 100 nm) gives rise to an effective gas interaction pathlength above 5 meters, an enhancement corresponding to 750 passes through a conventional multipass cell. This essentially different approach to pathlength enhancement opens a new route...

  14. Investigation of materials for inert electrodes in aluminum electrodeposition cells

    Energy Technology Data Exchange (ETDEWEB)

    Haggerty, J. S.; Sadoway, D. R.

    1987-09-14

    Work was divided into major efforts. The first was the growth and characterization of specimens; the second was Hall cell performance testing. Cathode and anode materials were the subject of investigation. Preparation of specimens included growth of single crystals and synthesis of ultra high purity powders. Special attention was paid to ferrites as they were considered to be the most promising anode materials. Ferrite anode corrosion rates were studied and the electrical conductivities of a set of copper-manganese ferrites were measured. Float Zone, Pendant Drop Cryolite Experiments were undertaken because unsatisfactory choices of candidate materials were being made on the basis of a flawed set of selection criteria applied to an incomplete and sometimes inaccurate data base. This experiment was then constructed to determine whether the apparatus used for float zone crystal growth could be adapted to make a variety of important based melts and their interactions with candidate inert anode materials. The third major topic was Non Consumable Anode (Data Base, Candidate Compositions), driven by our perception that the basis for prior selection of candidate materials was inadequate. Results are presented. 162 refs., 39 figs., 18 tabs.

  15. Solid oxide fuel cell material research in SICCAS

    Energy Technology Data Exchange (ETDEWEB)

    Wang, S.; Ye, X.; Zen, F.; Li, J.; Shi, J.; Wen, T. [Chinese Academy of Sciences, Shanghai Inst. of Ceramics, Shanghai (China). CAS Key Laboratory of Materials for Energy Conversion

    2010-07-01

    A fuel cell is a device that transfers the chemical energy of fuels directly to electricity. Because its high operating temperature enables the further application of the co-generated heat, the solid oxide fuel cell (SOFC) has the highest efficiency in different types of fuel cells. SICCAS has almost 15 years of experience in the research, development and manufacture of planar type SOFCs. In order to reduce the cost, extend the life time, and propel the commercialization of SOFCs, the company is now focusing on intermediate temperature SOFCs following an international tendency in this direction. Two options for reducing the operating temperatures involve decreasing the thickness of the electrolyte or adopting new materials with higher conductivity. This paper presented a study that used both these methods to make nickel (Ni)/yttria stabilized zirconia (YSZ) anode supported scandia-stabilized zirconia electrolyte composite membranes, using an astrocyte-derived extracellullar matrix (ASECM) with the tape casting technique. In order to evaluate various cathodes, single cells were also constructed on the ASECM. It was concluded that a cell with LBSM-GDC cathode could exhibit good activity, and the output power density reached 0.738W/cm2 at 750 degrees Celsius.

  16. Hydrogen like energy and materials for fuel cells

    International Nuclear Information System (INIS)

    The researches on the production, storage and the use of hydrogen like fuel or energy carrying are carried out in several laboratories around the world. In the Instituto Nacional de Investigaciones Nucleares (ININ), from the year of 1993 they are carried out researches about the synthesis of electro-catalysts materials than can serve in the hydrogen production starting from the electrolysis of the water, or in fuel cells, as well as of semiconductor materials for the photo-electrolysis of the water. Recently, in collaboration with other Departments of the ININ, the hydrogen production has been approached starting from fruit and vegetable wastes, with the purpose of evaluating the possibility that this residuals can be utilized for the energy obtaining and that they are not only garbage that causes problems of environmental pollution, generate toxic gases and pollute the soil with the organic acids that take place during their fermentation. (Author)

  17. Polyacylurethanes as Novel Degradable Cell Carrier Materials for Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Arend Jan Schouten

    2011-10-01

    Full Text Available Polycaprolactone (PCL polyester and segmented aliphatic polyester urethanes based on PCL soft segment have been thoroughly investigated as biodegradable scaffolds for tissue engineering. Although proven beneficial as long term implants, these materials degrade very slowly and are therefore not suitable in applications in which scaffold support is needed for a shorter time. A recently developed class of polyacylurethanes (PAUs is expected to fulfill such requirements. Our aim was to assess in vitro the degradation of PAUs and evaluate their suitability as temporary scaffold materials to support soft tissue repair. With both a mass loss of 2.5–3.0% and a decrease in molar mass of approx. 35% over a period of 80 days, PAUs were shown to degrade via both bulk and surface erosion mechanisms. Fourier Transform Infra Red (FTIR spectroscopy was successfully applied to study the extent of PAUs microphase separation during in vitro degradation. The microphase separated morphology of PAU1000 (molar mass of the oligocaprolactone soft segment = 1000 g/mol provided this polymer with mechano-physical characteristics that would render it a suitable material for constructs and devices. PAU1000 exhibited excellent haemocompatibility in vitro. In addition, PAU1000 supported both adhesion and proliferation of vascular endothelial cells and this could be further enhanced by pre-coating of PAU1000 with fibronectin (Fn. The contact angle of PAU1000 decreased both with in vitro degradation and by incubation in biological fluids. In endothelial cell culture medium the contact angle reached 60°, which is optimal for cell adhesion. Taken together, these results support the application of PAU1000 in the field of soft tissue repair as a temporary degradable scaffold.

  18. Cell Colonization Control by Physical and Chemical Modification of Materials

    Czech Academy of Sciences Publication Activity Database

    Bačáková, Lucie; Švorčík, V.

    New York : Nova Science Publisher, 2008 - (Kimura, D.), s. 5-56 ISBN 978-1-60456-132-6 R&D Projects: GA AV ČR(CZ) KAN400480701; GA AV ČR(CZ) KAN101120701; GA AV ČR(CZ) IAA5011301; GA AV ČR(CZ) 1QS500110564; GA ČR(CZ) GA204/06/0225; GA ČR(CZ) GA101/06/0226 Grant ostatní: GA Mšk(CZ) LC06041 Institutional research plan: CEZ:AV0Z50110509 Keywords : material surface modification * nanostructure * cell culture Subject RIV: EI - Biotechnology ; Bionics

  19. The anterior lens capsule used as support material in RPE cell-transplantation

    DEFF Research Database (Denmark)

    Nicolini, J; Kiilgaard, Jens Folke; Wiencke, A K;

    2000-01-01

    To investigate the use of an ocular basement membrane as support material for transplanted porcine RPE cells.......To investigate the use of an ocular basement membrane as support material for transplanted porcine RPE cells....

  20. Research on polycrystalline thin-film materials, cells, and modules

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, R.L.; Zweibel, K.; Ullal, H.S.

    1990-11-01

    The US Department of Energy (DOE) supports research activities in polycrystalline thin films through the Polycrystalline Thin-Film Program at the Solar Energy Research Institute (SERI). This program includes research and development (R D) in both copper indium diselenide and cadmium telluride thin films for photovoltaic applications. The objective of this program is to support R D of photovoltaic cells and modules that meet the DOE long-term goals of high efficiency (15%--20%), low cost ($50/m{sup 2}), and reliability (30-year life time). Research carried out in this area is receiving increased recognition due to important advances in polycrystalline thin-film CuInSe{sub 2} and CdTe solar cells and modules. These have become the leading thin-film materials for photovoltaics in terms of efficiency and stability. DOE has recognized this potential through a competitive initiative for the development of CuInSe{sub 2} and CdTe modules. This paper focuses on the recent progress and future directions of the Polycrystalline Thin-Film Program and the status of the subcontracted research on these promising photovoltaic materials. 26 refs., 12 figs, 1 tab.

  1. Research on polycrystalline thin-film materials, cells, and modules

    Science.gov (United States)

    Mitchell, R. L.; Zweibel, K.; Ullal, H. S.

    1990-11-01

    DOE supports research activities in polycrystalline thin films through the Polycrystalline Thin Film Program. This program includes includes R and D in both copper indium diselenide and cadmium telluride thin films for photovoltaic applications. The objective is to support R and D of photovoltaic cells and modules that meet the DOE long term goals of high efficiency (15 to 20 percent), low cost ($50/sq cm), and reliability (30-year life time). Research carried out in this area is receiving increased recognition due to important advances in polycrystalline thin film CuInSe2 and CdTe solar cells and modules. These have become the leading thin film materials for photovoltaics in terms of efficiency and stability. DOE has recognized this potential through a competitive initiative for the development of CuInSe(sub 2) and CdTe modules. The recent progress and future directions are studied of the Polycrystalline Thin Film Program and the status of the subcontracted research on these promising photovoltaic materials.

  2. Cornell Fuel Cell Institute: Materials Discovery to Enable Fuel Cell Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Abruna, H.D.; DiSalvo, Francis J.

    2012-06-29

    The discovery and understanding of new, improved materials to advance fuel cell technology are the objectives of the Cornell Fuel Cell Institute (CFCI) research program. CFCI was initially formed in 2003. This report highlights the accomplishments from 2006-2009. Many of the grand challenges in energy science and technology are based on the need for materials with greatly improved or even revolutionary properties and performance. This is certainly true for fuel cells, which have the promise of being highly efficient in the conversion of chemical energy to electrical energy. Fuel cells offer the possibility of efficiencies perhaps up to 90 % based on the free energy of reaction. Here, the challenges are clearly in the materials used to construct the heart of the fuel cell: the membrane electrode assembly (MEA). The MEA consists of two electrodes separated by an ionically conducting membrane. Each electrode is a nanocomposite of electronically conducting catalyst support, ionic conductor and open porosity, that together form three percolation networks that must connect to each catalyst nanoparticle; otherwise the catalyst is inactive. This report highlights the findings of the three years completing the CFCI funding, and incudes developments in materials for electrocatalyts, catalyst supports, materials with structured and functional porosity for electrodes, and novel electrolyte membranes. The report also discusses developments at understanding electrocatalytic mechanisms, especially on novel catalyst surfaces, plus in situ characterization techniques and contributions from theory. Much of the research of the CFCI continues within the Energy Materials Center at Cornell (emc2), a DOE funded, Office of Science Energy Frontier Research Center (EFRC).

  3. Material properties of the cell dictate stress-induced spreading and differentiation in embryonic stem cells

    Science.gov (United States)

    Chowdhury, Farhan; Na, Sungsoo; Li, Dong; Poh, Yeh-Chuin; Tanaka, Tetsuya S.; Wang, Fei; Wang, Ning

    2010-01-01

    Growing evidence suggests that physical microenvironments and mechanical stresses, in addition to soluble factors, help direct mesenchymal-stem-cell fate. However, biological responses to a local force in embryonic stem cells remain elusive. Here we show that a local cyclic stress through focal adhesions induced spreading in mouse embryonic stem cells but not in mouse embryonic stem-cell-differentiated cells, which were ten times stiffer. This response was dictated by the cell material property (cell softness), suggesting that a threshold cell deformation is the key setpoint for triggering spreading responses. Traction quantification and pharmacological or shRNA intervention revealed that myosin II contractility, F-actin, Src or cdc42 were essential in the spreading response. The applied stress led to oct3/4 gene downregulation in mES cells. Our findings demonstrate that cell softness dictates cellular sensitivity to force, suggesting that local small forces might have far more important roles in early development of soft embryos than previously appreciated.

  4. Ultra-thin solid oxide fuel cells: Materials and devices

    Science.gov (United States)

    Kerman, Kian

    Solid oxide fuel cells are electrochemical energy conversion devices utilizing solid electrolytes transporting O2- that typically operate in the 800 -- 1000 °C temperature range due to the large activation barrier for ionic transport. Reducing electrolyte thickness or increasing ionic conductivity can enable lower temperature operation for both stationary and portable applications. This thesis is focused on the fabrication of free standing ultrathin (creative processing schemes to experimentally test devices in a high temperature dual environment chamber. We present a simple elastic model to determine stable buckling configurations for free standing oxide membranes. This guides the experimental methodology for Y 2O3-doped ZrO2 film processing, which enables tunable internal stress in the films. Using these criteria, we fabricate robust Y2O3-doped ZrO2 membranes on Si and composite polymeric substrates by semiconductor and micro-machining processes, respectively. Fuel cell devices integrating these membranes with metallic electrodes are demonstrated to operate in the 300 -- 500 °C range, exhibiting record performance at such temperatures. A model combining physical transport of electronic carriers in an insulating film and electrochemical aspects of transport is developed to determine the limits of performance enhancement expected via electrolyte thickness reduction. Free standing oxide heterostructures, i.e. electrolyte membrane and oxide electrodes, are demonstrated. Lastly, using Y2O3-doped ZrO2 and Gd2O 3-doped CeO2, novel electrolyte fabrication schemes are explored to develop oxide alloys and nanoscale compositionally graded membranes that are thermomechanically robust and provide added interfacial functionality. The work in this thesis advances experimental state-of-the-art with respect to solid oxide fuel cell operation temperature, provides fundamental boundaries expected for ultrathin electrolytes, develops the ability to integrate highly dissimilar

  5. 49 CFR 173.230 - Fuel cell cartridges containing hazardous material.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Fuel cell cartridges containing hazardous material... Than Class 1 and Class 7 § 173.230 Fuel cell cartridges containing hazardous material. (a) Requirements for Fuel Cell Cartridges. Fuel cell cartridges, including when contained in or packed with...

  6. Gelatin methacrylamide as coating material in cell culture.

    Science.gov (United States)

    Egger, Michael; Tovar, Günter E M; Hoch, Eva; Southan, Alexander

    2016-01-01

    Unmodified gelatin (uG) is widely used as a coating material in cell culture for improving surface properties. In this study, the authors investigated if gelatin methacrylamide (GM) with a medium degree of methacrylamide modification (GM1.5) and a high degree of methacrylamide modification (GM4) are equally suitable for this purpose. Therefore, gold surfaces were coated with uG, GM1.5, and GM4 by adsorption of the polymers on the surfaces. Coating success was confirmed by spectroscopic ellipsometry, contact angle measurements, surface plasmon resonance spectroscopy (SPRS), and atomic force microscopy (AFM). The authors found that upon adsorption of uG, GM1.5, a nd GM4 on gold, thin films with thicknesses of 2.95 nm, 2.50 nm, and 2.26 nm were formed. The coated surfaces showed advancing contact angles of 46° (uG and GM1.5) and 52° (GM4) without alteration of the surface roughness determined by AFM. Protein adsorption taking place on the coated surfaces was measured during contact of the surfaces with fetal calf serum by SPRS. Protein adsorption on the coated surfaces was reduced by the factor of 6.4 (uG), 5.4 (GM1.5), and 4.6 (GM4) compared to gold surfaces. Human fibroblasts cultured on the surfaces showed excellent viability shown by water soluble tetrazolium salt assay as well as live/dead staining with propidium iodide and fluorescein diacetate. No cytotoxic effects of the GM coated surfaces were observed, giving rise to the conclusion that GMs are suitable materials as coatings in cell culture. PMID:27177620

  7. Chemically Deposited Thin-Film Solar Cell Materials

    Science.gov (United States)

    Raffaelle, R.; Junek, W.; Gorse, J.; Thompson, T.; Harris, J.; Hehemann, D.; Hepp, A.; Rybicki, G.

    2005-01-01

    We have been working on the development of thin film photovoltaic solar cell materials that can be produced entirely by wet chemical methods on low-cost flexible substrates. P-type copper indium diselenide (CIS) absorber layers have been deposited via electrochemical deposition. Similar techniques have also allowed us to incorporate both Ga and S into the CIS structure, in order to increase its optical bandgap. The ability to deposit similar absorber layers with a variety of bandgaps is essential to our efforts to develop a multi-junction thin-film solar cell. Chemical bath deposition methods were used to deposit a cadmium sulfide (CdS) buffer layers on our CIS-based absorber layers. Window contacts were made to these CdS/CIS junctions by the electrodeposition of zinc oxide (ZnO). Structural and elemental determinations of the individual ZnO, CdS and CIS-based films via transmission spectroscopy, x-ray diffraction, x-ray photoelectron spectroscopy and energy dispersive spectroscopy will be presented. The electrical characterization of the resulting devices will be discussed.

  8. Block copolymers for alkaline fuel cell membrane materials

    Science.gov (United States)

    Li, Yifan

    Alkaline fuel cells (AFCs) using anion exchange membranes (AEMs) as electrolyte have recently received considerable attention. AFCs offer some advantages over proton exchange membrane fuel cells, including the potential of non-noble metal (e.g. nickel, silver) catalyst on the cathode, which can dramatically lower the fuel cell cost. The main drawback of traditional AFCs is the use of liquid electrolyte (e.g. aqueous potassium hydroxide), which can result in the formation of carbonate precipitates by reaction with carbon dioxide. AEMs with tethered cations can overcome the precipitates formed in traditional AFCs. Our current research focuses on developing different polymer systems (blend, block, grafted, and crosslinked polymers) in order to understand alkaline fuel cell membrane in many aspects and design optimized anion exchange membranes with better alkaline stability, mechanical integrity and ionic conductivity. A number of distinct materials have been produced and characterized. A polymer blend system comprised of poly(vinylbenzyl chloride)-b-polystyrene (PVBC-b-PS) diblock copolymer, prepared by nitroxide mediated polymerization (NMP), with poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) or brominated PPO was studied for conversion into a blend membrane for AEM. The formation of a miscible blend matrix improved mechanical properties while maintaining high ionic conductivity through formation of phase separated ionic domains. Using anionic polymerization, a polyethylene based block copolymer was designed where the polyethylene-based block copolymer formed bicontinuous morphological structures to enhance the hydroxide conductivity (up to 94 mS/cm at 80 °C) while excellent mechanical properties (strain up to 205%) of the polyethylene block copolymer membrane was observed. A polymer system was designed and characterized with monomethoxy polyethylene glycol (mPEG) as a hydrophilic polymer grafted through substitution of pendent benzyl chloride groups of a PVBC

  9. Evaluation for cell affinity of the composite material containing carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    KANG Shizhao; WAN Yuqing; YAN Huijuan; BEI Jianzhong; WANG Chen; WANG Shenguo; WANG Chunru; WAN Lijun; BAI Chunli

    2004-01-01

    The composite material of poly-(L-lactide) (PLLA) and carbon nanotubes (CNTs) were prepared. Its surface morphologies and property were worked out by using atomic force microscopy (AFM) and contact angle measurement. Moreover, the prime cytocompatibility was used to investigate the biocompatibility of the composite material containing CNTs and the effects of CNTs on one aspect of cell function, cell affinity. The results obtained indicate that the composite material of PLLA and CNTs possesses good biocompatibility for both the 3T3 fibroblasts and Oct-1 osteoblast-like cells. The addition of CNTs will greatly affect cell affinity of the material, which may be disadvantage for the cell adhesion.

  10. A review of composite and metallic bipolar plates in proton exchange membrane fuel cell: Materials, fabrication, and material selection

    Science.gov (United States)

    Taherian, Reza

    2014-11-01

    Proton exchange membrane (PEM) fuel cells offer exceptional potential for a clean, efficient, and reliable power source. The bipolar plate (BP) is a key component in this device, as it connects each cell electrically, supplies reactant gases to both anode and cathode, and removes reaction products from the cell. BPs have primarily been fabricated from high-density graphite, but in recent years, much attention has been paid to develop the cost-effective and feasible alternative materials. Recently, two different classes of materials have been attracted attention: metals and composite materials. This paper offers a comprehensive review of the current researches being carried out on the metallic and composite BPs, covering materials and fabrication methods. In this research, the phenomenon of ionic contamination due to the release of the corrosion products of metallic BP and relative impact on the durability as well as performance of PEM fuel cells is extensively investigated. Furthermore, in this paper, upon several effective parameters on commercialization of PEM fuel cells, such as stack cost, weight, volume, durability, strength, ohmic resistance, and ionic contamination, a material selection is performed among the most common BPs currently being used. This material selection is conducted by using Simple Additive Weighting Method (SAWM).

  11. Recent progress in stem cell differentiation directed by material and mechanical cues.

    Science.gov (United States)

    Lin, Xunxun; Shi, Yuan; Cao, Yilin; Liu, Wei

    2016-02-01

    Stem cells play essential roles in tissue regeneration in vivo via specific lineage differentiation induced by environmental factors. In the past, biochemical signals were the focus of induced stem cell differentiation. As reported by Engler et al (2006 Cell 126 677-89), biophysical signal mediated stem cell differentiation could also serve as an important inducer. With the advancement of material science, it becomes a possible strategy to generate active biophysical signals for directing stem cell fate through specially designed material microstructures. In the past five years, significant progress has been made in this field, and these designed biophysical signals include material elasticity/rigidity, micropatterned structure, extracellular matrix (ECM) coated materials, material transmitted extracellular mechanical force etc. A large number of investigations involved material directed differentiation of mesenchymal stem cells, neural stem/progenitor cells, adipose derived stem cells, hematopoietic stem/progenitor cells, embryonic stem cells and other cells. Hydrogel based materials were commonly used to create varied mechanical properties via modifying the ratio of different components, crosslinking levels, matrix concentration and conjugation with other components. Among them, polyacrylamide (PAM) and polydimethylsiloxane (PDMS) hydrogels remained the major types of material. Specially designed micropatterning was not only able to create a unique topographical surface to control cell shape, alignment, cell-cell and cell-matrix contact for basic stem cell biology study, but also could be integrated with 3D bioprinting to generate micropattered 3D structure and thus to induce stem cell based tissue regeneration. ECM coating on a specific topographical structure was capable of inducing even more specific and potent stem cell differentiation along with soluble factors and mechanical force. The article overviews the progress of the past five years in this particular

  12. Advanced Materials for PEM-Based Fuel Cell Systems

    Energy Technology Data Exchange (ETDEWEB)

    James E. McGrath

    2005-10-26

    Proton exchange membrane fuel cells (PEMFCs) are quickly becoming attractive alternative energy sources for transportation, stationary power, and small electronics due to the increasing cost and environmental hazards of traditional fossil fuels. Two main classes of PEMFCs include hydrogen/air or hydrogen/oxygen fuel cells and direct methanol fuel cells (DMFCs). The current benchmark membrane for both types of PEMFCs is Nafion, a perfluorinated sulfonated copolymer made by DuPont. Nafion copolymers exhibit good thermal and chemical stability, as well as very high proton conductivity under hydrated conditions at temperatures below 80 °C. However, application of these membranes is limited due to their high methanol permeability and loss of conductivity at high temperatures and low relative humidities. These deficiencies have led to the search for improved materials for proton exchange membranes. Potential PEMs should have good thermal, hydrolytic, and oxidative stability, high proton conductivity, selective permeability, and mechanical durability over long periods of time. Poly(arylene ether)s, polyimides, polybenzimidazoles, and polyphenylenes are among the most widely investigated candidates for PEMs. Poly(arylene ether)s are a promising class of proton exchange membranes due to their excellent thermal and chemical stability and high glass transition temperatures. High proton conductivity can be achieved through post-sulfonation of poly(arylene ether) materials, but this most often results in very high water sorption or even water solubility. Our research has shown that directly polymerized poly(arylene ether) copolymers show important advantages over traditional post-sulfonated systems and also address the concerns with Nafion membranes. These properties were evaluated and correlated with morphology, structure-property relationships, and

  13. Advanced Materials for PEM-Based Fuel Cell Systems

    Energy Technology Data Exchange (ETDEWEB)

    James E. McGrath; Donald G. Baird; Michael von Spakovsky

    2005-10-26

    Proton exchange membrane fuel cells (PEMFCs) are quickly becoming attractive alternative energy sources for transportation, stationary power, and small electronics due to the increasing cost and environmental hazards of traditional fossil fuels. Two main classes of PEMFCs include hydrogen/air or hydrogen/oxygen fuel cells and direct methanol fuel cells (DMFCs). The current benchmark membrane for both types of PEMFCs is Nafion, a perfluorinated sulfonated copolymer made by DuPont. Nafion copolymers exhibit good thermal and chemical stability, as well as very high proton conductivity under hydrated conditions at temperatures below 80 degrees C. However, application of these membranes is limited due to their high methanol permeability and loss of conductivity at high temperatures and low relative humidities. These deficiencies have led to the search for improved materials for proton exchange membranes. Potential PEMs should have good thermal, hydrolytic, and oxidative stability, high proton conductivity, selective permeability, and mechanical durability over long periods of time. Poly(arylene ether)s, polyimides, polybenzimidazoles, and polyphenylenes are among the most widely investigated candidates for PEMs. Poly(arylene ether)s are a promising class of proton exchange membranes due to their excellent thermal and chemical stability and high glass transition temperatures. High proton conductivity can be achieved through post-sulfonation of poly(arylene ether) materials, but this most often results in very high water sorption or even water solubility. Our research has shown that directly polymerized poly(arylene ether) copolymers show important advantages over traditional post-sulfonated systems and also address the concerns with Nafion membranes. These properties were evaluated and correlated with morphology, structure-property relationships, and states of water in the membranes. Further improvements in properties were achieved through incorporation of inorganic

  14. TPV energy conversion: A review of material and cell related issues

    Energy Technology Data Exchange (ETDEWEB)

    Bhat, I.B.; Borrego, J.M.; Gutmann, R.J.; Ostrogorsky, A.G. [Rensselaer Polytechnic Inst., Troy, NY (United States). Center for Integrated Electronics and Electronic Manufacturing

    1996-08-01

    This paper presents an overview of thermophotovoltaic (TPV) energy conversion using low band gap semiconductor photovoltaic cells. Physics of PN junctions related to TPV cells is described and the factors that affect overall cell efficiencies are outlined. Current status of bulk and epitaxial growth of TPV materials and cell fabrication issues are also described.

  15. Light conversion materials for solar cells by atomic layer deposition

    OpenAIRE

    2014-01-01

    There are many different solar cell technologies which aim at producing electricity from sunlight cheap and/or efficient. As the efficiency of silicon cells is slowly but continuously climbing, price plummeting, and production skyrocketing, there is in my opinion little room for other technologies unless they can beat silicon on efficiency. Commercial cells at over 20 % efficiency are available and lab cells have been reported at above 27 %. Comparing this to the theoretical maximum efficienc...

  16. Tutorial: Electroporation of cells in complex materials and tissue

    Science.gov (United States)

    Rems, L.; Miklavčič, D.

    2016-05-01

    Electroporation is being successfully used in biology, medicine, food processing, and biotechnology, and in some environmental applications. Recent applications also include in addition to classical electroporation, where cells are exposed to micro- or milliseconds long pulses, exposures to extremely short nanosecond pulses, i.e., high-frequency electroporation. Electric pulses are applied to cells in different structural configurations ranging from suspended cells to cells in tissues. Understanding electroporation of cells in tissues and other complex environments is a key to its successful use and optimization in various applications. Thus, explanation will be provided theoretically/numerically with relation to experimental observations by scaling our understanding of electroporation from the molecular level of the cell membrane up to the tissue level.

  17. Karakterisasi Simplisia dan Skrining Fitokimia serta Uji Aktivitas Antioksidan Ekstrak Etanol Buah Naga (Hylocereus undatus (Haw.) Britton & Rose)

    OpenAIRE

    Siregar, Nur Khaidah

    2011-01-01

    The dragon fruit plant (Hylocereus undatus (Haw.) Britton & Rose) family of cactaceae has been cultivated at Indonesia and increasingly popular for the community. Unique and interesting fruit shape, red of shell and green turtle similar to the turtle’s of dragon, it was sweet, sour and fresh, contain chemical compounds such as vitamin C, vitamin A vitamin E and polyphenols that can lowered blood pressure, cholesterol and blood glucose level, it also prevent spreading of cancer cell. In t...

  18. Characterization of thin-film silicon materials and solar cells through numerical modeling

    NARCIS (Netherlands)

    Pieters, B.E.

    2008-01-01

    At present most commercially available solar cells are made of crystalline silicon (c-Si). The disadvantages of crystalline silicon solar cells are the high material cost and energy consumption during production. A cheaper alternative can be found in thin-film silicon solar cells. The thin-film sili

  19. Cell-material interactions on biphasic polyurethane matrix.

    Science.gov (United States)

    Dicesare, Patrick; Fox, Wade M; Hill, Michael J; Krishnan, G Rajesh; Yang, Shuying; Sarkar, Debanjan

    2013-08-01

    Cell-matrix interaction is a key regulator for controlling stem cell fate in regenerative tissue engineering. These interactions are induced and controlled by the nanoscale features of extracellular matrix and are mimicked on synthetic matrices to control cell structure and functions. Recent studies have shown that nanostructured matrices can modulate stem cell behavior and exert specific role in tissue regeneration. In this study, we have demonstrated that nanostructured phase morphology of synthetic matrix can control adhesion, proliferation, organization and migration of human mesenchymal stem cells (MSCs). Nanostructured biodegradable polyurethanes (PU) with segmental composition exhibit biphasic morphology at nanoscale dimensions and can control cellular features of MSCs. Biodegradable PU with polyester soft segment and hard segment composed of aliphatic diisocyanates and dipeptide chain extender were designed to examine the effect polyurethane phase morphology. By altering the polyurethane composition, morphological architecture of PU was modulated and its effect was examined on MSC. Results show that MSCs can sense the nanoscale morphology of biphasic polyurethane matrix to exhibit distinct cellular features and, thus, signifies the relevance of matrix phase morphology. The role of nanostructured phases of a synthetic matrix in controlling cell-matrix interaction provides important insights for regulation of cell behavior on synthetic matrix and, therefore, is an important tool for engineering tissue regeneration. PMID:23255285

  20. Development of materials for fuel cell application by radiation technology

    International Nuclear Information System (INIS)

    The development of the single cell of SOFC with low operation temperature at and below 650 .deg. C(above 400 mW/cm2) Ο The development of fabrication method for the single cell of solid oxide fuel cell (SOFC) by dip-coating of nanoparticles such as NiO, YSZ, Ag, and Ag/C, etc. Ο The optimization of the preparation and performance of SOFC by using nanoparticles. Ο The preparation of samples for SOFC with large dimension. The development of fluoropolymer-based fuel cell membranes with crosslinked structure by radiation grafting technique Ο The development of fuel cell membranes with low methanol permeability via the introduction of novel monomers (e. g. vinylbenzyl chloride and vinylether chloride) by radiation grafting technique Ο The development of hydrocarbon fuel cell membrane by radiation crosslinking technique Ο The structure analysis and the evaluations of the property, performance, and radiation effect of the prepared membranes Ο The optimization of the preparation and performance of DMFC fuel cell membrane via the structure-property analysis (power: above 130 mW/cm2/50 cm2 at 5M methanol) Ο The preparation of samples for MEA stack assembly

  1. Azomethine-based Donor Materials for Organic Solar Cells

    OpenAIRE

    Petrus,M. L.

    2014-01-01

    Solution processable organic photovoltaics (OPVs) are attracting much attention because of their anticipated advantages such as low cost, flexibility, lightweight, and the potential to be produced on a large scale. The photoactive layer of OPVs consists of a blend of an electron donating and an electron accepting material. Over the last 20 years, a plethora of (record breaking) electron‐donating materials have been reported, which are mostly synthesized via transition metal mediated aryl‐aryl...

  2. Proton Exchange Membrane (PEM) Material Synthetic Design for Fuel Cells

    Institute of Scientific and Technical Information of China (English)

    Michael; D.Guiver; Dae-Sik; Kim; Gilles; P.Robertson; Yu; Seung; Kim; Bryan; S.Pivovar

    2007-01-01

    1 Results Hydrocarbon PEM materials are being widely studied as replacements for Nafion-type perfluorinated polymeric materials to reduce cost and improve performance such as operating temperature and methanol crossover in the DMFC application. Among some of the important property considerations required are thermal and chemical stability, low dimensional swelling, low methanol permeability in the case of DMFC and high proton conductivity. Careful structural design can reduce the effect of swelling as...

  3. Design of high temperature irradiation materials inspection cells. (Spent fuel inspection cells) in the High Temperature Engineering Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ino, Hiroichi; Ueta, Shouhei; Suzuki, Hiroshi; Sawa, Kazuhiro [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Tobita, Tsutomu [Nuclear Engineering Company, Ltd., Tokai, Ibaraki (Japan)

    2002-01-01

    This report summarizes design requirements and design results for shields, ventilation system and fuel handling devices for the high temperature irradiation materials inspection cells (spent fuel inspection cells). These cells are small cells to carry out few post-irradiation examinations of spent fuels, specimen, etc., which are irradiated in the High Temperature Engineering Test Reactor, since the cells should be built in limited space in the HTTR reactor building, the cells are designed considering relationship between the cells and the reactor building to utilize the limited space effectively. The cells consist of three partitioned hot cells with wall for neutron and gamma-ray shields, ventilation system including filtering units and fuel handling devices. The post-irradiation examinations of the fuels and materials are planed by using the cells and the Hot Laboratory of the Japan Materials Testing Reactor to establish the technology basis on high temperature gas-cooled reactors (HTGRs). In future, irradiation tests and post-irradiation examinations will be carried out with the cells to upgrade present HTGR technologies and to make the innovative basic research on high-temperature engineering. (author)

  4. Design of high temperature irradiation materials inspection cells. (Spent fuel inspection cells) in the High Temperature Engineering Test Reactor

    International Nuclear Information System (INIS)

    This report summarizes design requirements and design results for shields, ventilation system and fuel handling devices for the high temperature irradiation materials inspection cells (spent fuel inspection cells). These cells are small cells to carry out few post-irradiation examinations of spent fuels, specimen, etc., which are irradiated in the High Temperature Engineering Test Reactor, since the cells should be built in limited space in the HTTR reactor building, the cells are designed considering relationship between the cells and the reactor building to utilize the limited space effectively. The cells consist of three partitioned hot cells with wall for neutron and gamma-ray shields, ventilation system including filtering units and fuel handling devices. The post-irradiation examinations of the fuels and materials are planed by using the cells and the Hot Laboratory of the Japan Materials Testing Reactor to establish the technology basis on high temperature gas-cooled reactors (HTGRs). In future, irradiation tests and post-irradiation examinations will be carried out with the cells to upgrade present HTGR technologies and to make the innovative basic research on high-temperature engineering. (author)

  5. Polymer electrolyte fuel cells physical principles of materials and operation

    CERN Document Server

    Eikerling, Michael

    2014-01-01

    The book provides a systematic and profound account of scientific challenges in fuel cell research. The introductory chapters bring readers up to date on the urgency and implications of the global energy challenge, the prospects of electrochemical energy conversion technologies, and the thermodynamic and electrochemical principles underlying the operation of polymer electrolyte fuel cells. The book then presents the scientific challenges in fuel cell research as a systematic account of distinct components, length scales, physicochemical processes, and scientific disciplines. The main part of t

  6. Study of relationships of material properties and high efficiency solar cell performance on material composition

    Science.gov (United States)

    Sah, C. T.

    1983-01-01

    The performance improvements obtainable from extending the traditionally thin back-surface-field (BSF) layer deep into the base of silicon solar cells under terrestrial solar illumination (AM1) are analyzed. This extended BSF cell is also known as the back-drift-field cell. About 100 silicon cells were analyzed, each with a different emitter or base dopant impurity distribution whose selection was based on physically anticipated improvements. The four principal performance parameters (the open-circuit voltage, the short-circuit current, the fill factor, and the maximum efficiency) are computed using a FORTRAN program, called Circuit Technique for Semiconductor-device Analysis, CTSA, which numerically solves the six Shockley Equations under AM1 solar illumination at 88.92 mW/cm, at an optimum cell thickness of 50 um. The results show that very significant performance improvements can be realized by extending the BSF layer thickness from 2 um (18% efficiency) to 40 um (20% efficiency).

  7. Magnetic Nanowires as Materials for Cancer Cell Destruction

    KAUST Repository

    Contreras, Maria F.

    2015-12-01

    Current cancer therapies are highly cytotoxic and their delivery to exclusively the affected site is poorly controlled, resulting in unavoidable and often severe side effects. In an effort to overcome such issues, magnetic nanoparticles have been recently gaining relevance in the areas of biomedical applications and therapeutics, opening pathways to alternative methods. This led to the concept of magnetic particle hyperthermia in which magnetic nano beads are heated by a high power magnetic field. The increase in temperature kills the cancer cells, which are more susceptible to heat in comparison to healthy cells. In this dissertation, the possibility to kill cancer cells with magnetic nanowires is evaluated. The idea is to exploit a magnetomechanical effect, where nanowires cause cancer cell death through vibrating in a low power magnetic field. Specifically, the magnetic nanowires effects to cells in culture and their ability to induce cancer cell death, when combined with an alternating magnetic field, was investigated. Nickel and iron nanowires of 35 nm diameter and 1 to 5 μm long were synthesized by electrodeposition into nanoporous alumina templates, which were prepared using a two-step anodization process on highly pure aluminum substrates. For the cytotoxicity studies, the nanowires were added to cancer cells in culture, varying the incubation time and the concentration. The cell-nanowire interaction was thoroughly studied at the cellular level (mitochondrial metabolic activity, cell membrane integrity and, apoptosis/necrosis assay), and optical level (transmission electron and confocal microscopy). Furthermore, to investigate their therapeutic potential, an alternating magnetic field was applied varying its intensity and frequency. After the magnetic field application, cells health was measured at the mitochondrial activity level. Cytotoxicity results shed light onto the cellular tolerance to the nanowires, which helped in establishing the appropriate

  8. Titanium Dioxide as a Cathode Material in a Dry Cell

    OpenAIRE

    Duncan ALOKO; Eyitayo Amos AFOLABI

    2007-01-01

    Titanium dioxide was proposed as an alternative cathode material in place of Manganesse (IV) oxide. TiO2 was found to be highly polarized when in an electric field and its surface area of adsorption of solution determined to be 1070.32 m2/g. The adsorption of alkaline anions (i.e. SO42- , NO3-, Cl- and Br-) were investigated. The anions were adsorbed between the layers of the cathode material thereby altering its surface texture for a better performance. Increase in concentration of the anion...

  9. Development of materials and components for polymer electrolyte membrane fuel cells

    International Nuclear Information System (INIS)

    Fuel cells are important energy sources particularly in the automobile industry and have been fabricated from less than one kilowatt to more than one megawatt power sources. Proton exchange membrane Fuel cells have been successfully used for power generation and to run different types of vehicles. These are very efficient and pollution free energy sources. Fuel cells have also been used as stationary power sources. For the commercialization of fuel-cell technology on competitive basis and to gain a significant share of the electrical power market, cost-effective and durable materials and components are needed to be further developed although a lot of progress have been done. Main materials and components of fuel cells are catalysts, ion exchange membranes, membrane electrode assemblies, bipolar plates etc. Development of fuel cell materials is very important for the fabrication of fuel cells. Synthesis and characterization of different materials including catalysts, ion exchange membranes and carbon composite materials are described. Fabrication of different components of fuel cells including membrane electrode assemblies (MEAs), bipolar plates, and other hardware of fuel cells is discussed. (author)

  10. Cytotoxicity testing of materials with limited in vivo exposure is affected by the duration of cell-material contact.

    Science.gov (United States)

    Ciapetti, G; Granchi, D; Stea, S; Savarino, L; Verri, E; Gori, A; Savioli, F; Montanaro, L

    1998-12-15

    Silicones for dental impression largely are used to record the geometry of hard and soft dental tissues. They are considered to be medical devices, and the assessment of cytotoxicity is a necessary step in the evaluation of their biocompatibility. Extracts of six addition-type and six condensation-type silicones have been tested with L929 cells according to the ISO 10993-Part 5 standard. The cytotoxicity was evaluated by three different methods: neutral red uptake, propidium iodide (PI) staining, and amido black staining. According to the selected specific assay, contact between cells and material extracts was maintained for 24 h in the first series of experiments; then, considering that in vivo application of these materials is restricted to a few minutes, additional experiments were performed after 1 h of cell/extract contact. Analysis of the results showed that the addition-type silicones are nontoxic even when tested after prolonged exposure of the cells to the materials while the condensation-type silicones were cytotoxic at 24 h of incubation. Nevertheless, harm to the patient actually could be negligible, considering its very short time of exposure in vivo. This is supported by our finding that most are not toxic after 1 h. We suggest that the experimental conditions of cytotoxicity testing have to be relevant to the in vivo situation; accordingly, the time of exposure should be designed carefully. PMID:9827670

  11. OM-VPE grown materials for high efficiency solar cells

    Science.gov (United States)

    Saxena, R.; Cooper, B., III; Ludowise, M.; Borden, P.; Gregory, P.

    1980-01-01

    Organometallic sources are available for all the III-V elements and a variety of dopants; thus it is possible to use the technique to grow a wide variety of semiconductor compounds. AlGaAsSb and AlGaInAs alloys for multijunction monolithic solar cells were grown by OM-VPE. While the effort concentrated on terrestrial applications, the success of OM-VPE grown GaAs/AlGaAs concentrator solar cells (23% at 400 suns) demonstrates that OM-VPE is suitable for growing high efficiency solar cells in large quantities for space applications. In addition, OM-VPE offers the potential for substantial cost reduction of photovoltaic devices with scale up and automation and due to high process yield from reproducible, uniform epitaxial growths with excellent surface morphology.

  12. Engineering the Interface Between Inorganic Materials and Cells

    Energy Technology Data Exchange (ETDEWEB)

    Schaffer, David

    2014-05-31

    To further optimize cell function in hybrid “living materials”, it would be advantageous to render mammalian cells responsive to novel “orthogonal” cues, i.e. signals they would not ordinarily respond to but that can be engineered to feed into defined intracellular signaling pathways. We recently developed an optogenetic method, based on A. thaliana Cry2, for rapid and reversible protein oligomerization in response to blue light. We also demonstrated the ability to use this method to channel the light input into several defined signaling pathways, work that will enhance communication between inorganic devices and living systems.

  13. Evaluation of critical materials in five additional advance design photovoltaic cells

    Energy Technology Data Exchange (ETDEWEB)

    Smith, S.A.; Watts, R.L.; Martin, P.; Gurwell, W.E.

    1981-02-01

    The objective of this study is to identify potential material supply constraints due to the large-scale deployment of five advanced photovoltaic (PV) cell designs, and to suggest strategies to reduce the impacts of these production capacity limitations and potential future material shortages. The Critical Materials Assessment Program (CMAP) screens the designs and their supply chains and identifies potential shortages which might preclude large-scale use of the technologies. The results of the screening of five advanced PV cell designs are presented: (1) indium phosphide/cadmium sulfide, (2) zinc phosphide, (3) cadmium telluride/cadmium sulfide, (4) copper indium selenium, and (5) cadmium selenide photoelectrochemical. Each of these five cells is screened individually assuming that they first come online in 1991, and that 25 Gwe of peak capacity is online by the year 2000. A second computer screening assumes that each cell first comes online in 1991 and that each cell has a 5 GWe of peak capacity by the year 2000, so that the total online capacity for the five cells is 25 GWe. Based on a review of the preliminary baseline screening results, suggestions were made for varying such parameters as the layer thickness, cell production processes, etc. The resulting PV cell characterizations were then screened again by the CMAP computer code. The CMAP methodology used to identify critical materials is described; and detailed characterizations of the advanced photovoltaic cell designs under investigation, descriptions of additional cell production processes, and the results are presented. (WHK)

  14. Optimization of Cell Adhesion on Mg Based Implant Materials by Pre-Incubation under Cell Culture Conditions

    Directory of Open Access Journals (Sweden)

    Regine Willumeit

    2014-05-01

    Full Text Available Magnesium based implants could revolutionize applications where orthopedic implants such as nails, screws or bone plates are used because they are load bearing and degrade over time. This prevents a second surgery to remove conventional implants. To improve the biocompatibility we studied here if and for how long a pre-incubation of the material under cell culture conditions is favorable for cell attachment and proliferation. For two materials, Mg and Mg10Gd1Nd, we could show that 6 h pre-incubation are already enough to form a natural protective layer suitable for cell culture.

  15. Investigation of cell proliferative activity on the surface of the nanocomposite material produced by laser radiation

    Science.gov (United States)

    Zhurbina, N. N.; Kurilova, U. E.; Ickitidze, L. P.; Podgaetsky, V. M.; Selishchev, S. V.; Suetina, I. A.; Mezentseva, M. V.; Eganova, E. M.; Pavlov, A. A.; Gerasimenko, A. Y.

    2016-04-01

    A new method for the formation of composite nanomaterials based on multi-walled and single-walled carbon nanotubes (CNT) on a silicon substrate has been developed. Formation is carried out by ultrasound coating of a silicon substrate by homogenous dispersion of CNTs in the albumin matrix and further irradiation with the continuous laser beam with a wavelength of 810 nm and power of 5.5 watts. The high electrical conductivity of CNTs provides its structuring under the influence of the laser radiation electric field. The result is a scaffold that provides high mechanical strength of nanocomposite material (250 MPa). For in vitro studies of materials biocompatibility a method of cell growth microscopic analysis was developed. Human embryonic fibroblasts (EPP) were used as biological cells. Investigation of the interaction between nanocomposite material and cells was carried out by optical and atomic force microscopy depending on the time of cells incubation. The study showed that after 3 hours incubation EPP were fixed on the substrate surface, avoiding the surface of the composite material. However, after 24 hours of incubation EPP fix on the sample surface and then begin to grow and divide. After 72 hours of incubation, the cells completely fill the sample surface of nanocomposite material. Thus, a nanocomposite material based on CNTs in albumin matrix does not inhibit cell growth on its surface, and favours their growth. The nanocomposite material can be used for creating soft tissue implants

  16. Conducting polymer based materials for the fuel cell applications

    Czech Academy of Sciences Publication Activity Database

    Sapurina, I. Yu.; Stejskal, Jaroslav; Kompan, M.

    Sankt Peterburg : Fiziko-techničeskij Institut im. A. F. Ioffe, 2005. s. 39. [Meždunarodnyj Seminar: Rossijskie technologii dlja industrii /9./. 30.5.2005-1.6.2005, Sankt Peterburg] Institutional research plan: CEZ:AV0Z40500505 Keywords : fuel cell * conducting polymers Subject RIV: CD - Macromolecular Chemistry

  17. Nanoscale tissue engineering: spatial control over cell-materials interactions

    Energy Technology Data Exchange (ETDEWEB)

    Wheeldon, Ian; Farhadi, Arash; Bick, Alexander G; Khademhosseini, Ali [Center for Biomedical Engineering, Department of Medicine, Brigham and Women' s Hospital, Harvard Medical School, Boston, MA 02115 (United States); Jabbari, Esmaiel, E-mail: alik@rics.bwh.harvard.edu [Department of Chemical Engineering, University of South Carolina, Columbia, SC 29208 (United States)

    2011-05-27

    Cells interact with the surrounding environment by making tens to hundreds of thousands of nanoscale interactions with extracellular signals and features. The goal of nanoscale tissue engineering is to harness these interactions through nanoscale biomaterials engineering in order to study and direct cellular behavior. Here, we review two- and three-dimensional (2- and 3D) nanoscale tissue engineering technologies, and provide a holistic overview of the field. Techniques that can control the average spacing and clustering of cell adhesion ligands are well established and have been highly successful in describing cell adhesion and migration in 2D. Extension of these engineering tools to 3D biomaterials has created many new hydrogel and nanofiber scaffold technologies that are being used to design in vitro experiments with more physiologically relevant conditions. Researchers are beginning to study complex cell functions in 3D. However, there is a need for biomaterials systems that provide fine control over the nanoscale presentation of bioactive ligands in 3D. Additionally, there is a need for 2- and 3D techniques that can control the nanoscale presentation of multiple bioactive ligands and that can control the temporal changes in the cellular microenvironment. (topical review)

  18. Nanoscale tissue engineering: spatial control over cell-materials interactions

    International Nuclear Information System (INIS)

    Cells interact with the surrounding environment by making tens to hundreds of thousands of nanoscale interactions with extracellular signals and features. The goal of nanoscale tissue engineering is to harness these interactions through nanoscale biomaterials engineering in order to study and direct cellular behavior. Here, we review two- and three-dimensional (2- and 3D) nanoscale tissue engineering technologies, and provide a holistic overview of the field. Techniques that can control the average spacing and clustering of cell adhesion ligands are well established and have been highly successful in describing cell adhesion and migration in 2D. Extension of these engineering tools to 3D biomaterials has created many new hydrogel and nanofiber scaffold technologies that are being used to design in vitro experiments with more physiologically relevant conditions. Researchers are beginning to study complex cell functions in 3D. However, there is a need for biomaterials systems that provide fine control over the nanoscale presentation of bioactive ligands in 3D. Additionally, there is a need for 2- and 3D techniques that can control the nanoscale presentation of multiple bioactive ligands and that can control the temporal changes in the cellular microenvironment. (topical review)

  19. Hydrogenated microcrystalline silicon: from material to solar cells

    Czech Academy of Sciences Publication Activity Database

    Wyrsch, N.; Droz, C.; Feitknecht, L.; Goelitzer, M.; Kroll, U.; Meier, J.; Torres, P.; Vallat-Sauvain, E.; Shah, A.; Vaněček, Milan

    Vol. 609. Pittsburg : MRS, 2001, s. A15.1.1-A15.1.11. [MRS Spring Meeting 2000. San Francisco (US), 00.04.2000] Institutional research plan: CEZ:AV0Z1010914 Keywords : microcrystalline silicon * solar cells * defect density Subject RIV: BM - Solid Matter Physics ; Magnetism

  20. Materials requirements for high-efficiency silicon solar cells

    Science.gov (United States)

    Wolf, M.

    1985-01-01

    To achieve higher Si solar cell efficiencies (greater than 20%), better single-crystal Si must be produced. It is believed possible to bring Cz (Czochralski) Si up to the same low recombination level as FZ (Float Zone) Si. It is also desirable that solar cell Si meet the following requirements: long minority carrier lifetime (0.2 ohm-cm p-type with tau less than 500 microsec); repeatedly uniform lifetime (not spread from 50 to 1000 microsec); a lifetime that does not decrease during normal device processing; a silicon wafer sheet that is flat and stays throughout normal device processing; uniform and reasonable mechanical strength; and, manufacture at low cost (less than $50/sq m).

  1. Hydroxyapatite nanopowders: Synthesis, densification and cell-materials interaction

    International Nuclear Information System (INIS)

    Hydroxyapatite (HA) nanopowders with different aspect ratios were synthesized using reverse micelle template system. Nanopowders were characterized using X-ray diffraction (XRD), BET specific average surface area analysis and transmission electron microscopy (TEM). It was observed that increase in aqueous to organic ratio (A/O) and pH decreased the aspect ratio of the nanopowders. HA nanopowders with the highest aspect ratio (rod-shaped) of 7.2 ± 3.2 and the lowest aspect ratio (spherical) of 1.3 ± 0.3 were synthesized for processing dense compacts. Effect of powder morphology on densification at 1250 oC was studied with different amount of rod-shaped and spherical nanopowders. It was observed that an increase in high aspect ratio powder content in the compacts decreased sintered density under pressureless sintering condition. Also, due to excessive grain growth, no nanoscale morphology could be retained in the sintered microstructure. Mineralization study in simulated body fluid (SBF) showed formation of apatite layer on the entire surface of both compacts made with spherical and rod-shaped particles. Cytotoxicity result with OPC1 human osteoblast cells showed excellent cell attachment and cell spreading on samples after 5 days in culture

  2. Advanced Materials for the Recognition and Capture of Whole Cells and Microorganisms.

    Science.gov (United States)

    Bole, Amanda L; Manesiotis, Panagiotis

    2016-07-01

    Selective cell recognition and capture has recently attracted significant interest due to its potential importance for clinical, diagnostic, environmental, and security applications. Current methods for cell isolation from complex samples are largely dependent on cell size and density, with limited application scope as many of the target cells do not exhibit appreciable differences in this respect. The most recent and forthcoming developments in the area of selective recognition and capture of whole cells, based on natural receptors, as well as synthetic materials utilising physical and chemical properties of the target cell or microorganism, are highlighted. Particular focus is given to the development of cell complementary surfaces using the cells themselves as templating agents, by means of molecular imprinting, and their combination with sensing platforms for rapid cell detection in complex media. The benefits and challenges of each approach are discussed and a perspective of the future of this research area is given. PMID:26662854

  3. Evaluation of MHD materials for use in high-temperature fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Guidotti, R.

    1978-06-15

    The MHD and high-temperature fuel cell literature was surveyed for data pertaining to materials properties in order to identify materials used in MHD power generation which also might be suitable for component use in high-temperature fuel cells. Classes of MHD-electrode materials evaluated include carbides, nitrides, silicides, borides, composites, and oxides. Y/sub 2/O/sub 3/-stabilized ZrO/sub 2/ used as a reference point to evaluate materials for use in the solid-oxide fuel cell. Physical and chemical properties such as electrical resistivity, coefficient of thermal expansion, and thermodynamic stability toward oxidation were used to screen candidate materials. A number of the non-oxide ceramic MHD-electrode materials appear promising for use in the solid-electrolyte and molten-carbonate fuel cell as anodes or anode constituents. The MHD-insulator materials appear suitable candidates for electrolyte-support tiles in the molten-carbonate fuel cells. The merits and possible problem areas for these applications are discussed and additional needed areas of research are delineated.

  4. Small Punch Test Techniques for Irradiated Materials in Hot Cell

    International Nuclear Information System (INIS)

    Detailed procedures of the small punch test including the apparatus, the definition of small punch-related parameters, and the interpretation of results were presented. The testing machine should have a capability of the compressive loading and unloading at a given deflection level. The small punch specimen holder consists of an upper and lower die and clamping screws. The clamped specimen is deformed by using ball or spherical head punch. Two type of specimens with a circular and a square shape were used. The irradiated small punch specimen is made from the undamaged portion of the broken CVN bars or prepared by the irradiation of the specimen fabricated from the fresh materials. The heating and cooling devices should have the capability of the temperature control within ±2 .deg. C for the target value during the test. Based on the load-deflection data obtained from the small punch test. the empirical correlation between the small punch related parameters and a tensile properties such as 0.2% yield strength and ultimate tensile strength, fracture toughness, ductile-brittle transition temperature and creep properties determined from the standard test method is established and used to evaluate the mechanical properties of an irradiated materials. In addition, from the quantitative fractographic assessment of small punch test specimens, the relationship between the small punch energy and the quantity of ductile crack growth is obtained. Analytical formulations demonstrated good agreement with experimental load-deflection curves

  5. Novel Materials for High Efficiency Direct Methanol Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Carson, Stephen; Mountz, David; He, Wensheng; Zhang, Tao

    2013-12-31

    Direct methanol fuel cell membranes were developed using blends of different polyelectrolytes with PVDF. The membranes showed complex relationships between polyelectrolyte chemistry, morphology, and processing. Although the PVDF grade was found to have little effect on the membrane permselectivity, it does impact membrane conductivity and methanol permeation values. Other factors, such as varying the polyelectrolyte polarity, using varying crosslinking agents, and adjusting the equivalent weight of the membranes impacted methanol permeation, permselectivity, and areal resistance. We now understand, within the scope of the project work completed, how these inter-related performance properties can be tailored to achieve a balance of performance.

  6. Investigation of altenative carbon materials for fuel-cell catalyst support

    DEFF Research Database (Denmark)

    Larsen, Mikkel Juul

    large surface area and good anchoring properties make it a suited material for this purpose, it is prone to degradation in the fuel-cell environment. Thus alternative materials with higher durability than CB, but with similar (or better) capability of dispersion, are desired. Among them are highly...

  7. The hot cell laboratories for material investigations of the Institute for Safety Research

    Energy Technology Data Exchange (ETDEWEB)

    Viehrig, H.W.

    1998-10-01

    Special facilities for handling and testing of irradiated specimens are necessary, to perform the investigation of activated material. The Institute for Safety Research has two hot cell laboratories: - the preparation laboratory and - the materials testing laboratory. This report is intended to give an overview of the available facilities and developed techniques in the laboratories. (orig.)

  8. A viable electrode material for use in microbial fuel cells for tropical regions

    DEFF Research Database (Denmark)

    Offei, Felix; Thygesen, Anders; Mensah, Moses;

    2016-01-01

    Electrode materials are critical for microbial fuel cells (MFC) since they influence the construction and operational costs. This study introduces a simple and efficient electrode material in the form of palm kernel shell activated carbon (AC) obtained in tropical regions. The novel introduction...

  9. Development of new proton conducting materials for intermediate temperature fuel cells

    OpenAIRE

    Xu, Xiaoxiang

    2010-01-01

    Electronic version excludes material for which permission has not been granted by the rights holder The work in this thesis mainly focuses on the preparation and characterization of several phosphates and solid oxide systems with the aim of developing new proton conducting materials for intermediate temperature fuel cells (ITFCs). Soft chemical methods such as sol-gel methods and conventional solid state methods were applied for the synthesis of these materials. Aluminum phosphate obtai...

  10. Multi-Material Front Contact for 19% Thin Film Solar Cells

    OpenAIRE

    Joop van Deelen; Yasemin Tezsevin; Marco Barink

    2016-01-01

    The trade-off between transmittance and conductivity of the front contact material poses a bottleneck for thin film solar panels. Normally, the front contact material is a metal oxide and the optimal cell configuration and panel efficiency were determined for various band gap materials, representing Cu(In,Ga)Se2 (CIGS), CdTe and high band gap perovskites. Supplementing the metal oxide with a metallic copper grid improves the performance of the front contact and aims to increase the efficiency...

  11. Hexaazatrinaphthylene Derivatives: Efficient Electron-Transporting Materials with Tunable Energy Levels for Inverted Perovskite Solar Cells.

    Science.gov (United States)

    Zhao, Dongbing; Zhu, Zonglong; Kuo, Ming-Yu; Chueh, Chu-Chen; Jen, Alex K-Y

    2016-07-25

    Hexaazatrinaphthylene (HATNA) derivatives have been successfully shown to function as efficient electron-transporting materials (ETMs) for perovskite solar cells (PVSCs). The cells demonstrate a superior power conversion efficiency (PCE) of 17.6 % with negligible hysteresis. This study provides one of the first nonfullerene small-molecule-based ETMs for high-performance p-i-n PVSCs. PMID:27273656

  12. Scanning tunneling spectroscopy on the chalcopyrite solar cell absorber material Cu(In,Ga)Se2

    International Nuclear Information System (INIS)

    Cu(In,Ga)Se2-based thin film solar cells have reached efficiencies close to 20%. Nevertheless, little is known about electronic transport and carrier recombination in this material on a microscopic scale. Especially grain boundaries in these polycrystalline materials are considered to play an important role in the performance of these solar cells. We applied scanning tunneling microscopy and spectroscopy to gain more insight in the electronic microstructure of the material. Our results point to lateral electronic inhomogeneities on the absorber surface and to an enhanced density of states at grain boundaries. The influence of charging effects is discussed

  13. Polymer Materials for Fuel Cell Membranes :Sulfonated Poly(ether sulfone) for Universal Fuel Cell Operations

    Institute of Scientific and Technical Information of China (English)

    Hyoung-Juhn Kim

    2005-01-01

    @@ 1Introduction Polymer electrolyte fuel cells (PEFCs) have been spotlighted because they are clean and highly efficient power generation system. Proton exchange membrane fuel cells (PEMFCs), which use reformate gases or pure H2 for a fuel, have been employed for automotives and residential usages. Also, liquid-feed fuel cells such as direct methanol fuel cell (DMFC) and direct formic acid fuel cell (DFAFC) were studied for portable power generation.

  14. Hybrid Direct Carbon Fuel Cell Performance with Anode Current Collector Material

    DEFF Research Database (Denmark)

    Deleebeeck, Lisa; Kammer Hansen, Kent

    2015-01-01

    The influence of the current collector on the performance of a hybrid direct carbon fuel cell (HDCFC), consisting of solid oxide fuel cell (SOFC) with a molten carbonate-carbon slurry in contact with the anode, has been investigated using current-voltage curves. Four different anode current...... collectors were studied: Au, Ni, Ag, and Pt. It was shown that the performance of the direct carbon fuel cell (DCFC) is dependent on the current collector materials, Ni and Pt giving the best performance, due to their catalytic activity. Gold is suggested to be the best material as an inert current collector...

  15. Remote replacement of materials open-test assembly specimens at the FFTF/IEM cell

    International Nuclear Information System (INIS)

    The Fast Flux Test Facility (FFTF) interim examination and maintenance (IEM) cell is used for the remote disassembly of irradiated fuel and materials experiments. The materials open-test assembly (MOTA) is brought to the IEM cell for materials test specimen removal. The specimens are shipped to the materials laboratory for sorting and installation in new specimen holders and then returned within 10 days to the IEM cell where they are installed in a new MOTA vehicle for further irradiation. Reconstituting a MOTA is a challenging remote operation involving dozens of steps and two separate facilities. Handling and disassembling sodium-wetted components pose interesting handling, cleaning, and disposal challenges. The success of this system is evidenced by its timely completion in the critical path of FFTF outage schedules

  16. Development of high band gap materials for tandem solar cells and simulation studies on mechanical tandem solar cells

    Science.gov (United States)

    Vijayakumar, Vishnuvardhanan

    Development of low cost, high efficiency tandem solar cells is essential for large scale adoption of solar energy especially in densely populated regions of the world. In this thesis four-terminal mechanical (stack like) tandem solar cells were evaluated using detailed simulation models and design criteria for selecting candidate materials were established. Since silicon solar cells are low cost and have a multi-giga watt global manufacturing and supply chain capacity already in place then only tandem stacks incorporating silicon as one of the layers in the device was investigated. Two candidate materials which have high band gaps that could be used as top cells in the mechanical tandem device were explored as part of the thesis. Dye-sensitized solar cells (DSSC) sensitized with N719 dye (one of the candidates for the top cell) were fabricated with the goal of enabling a flexible processing path to lower cost. Stainless steel (SS) mesh substrates were used to fabricate anodes for flexible DSSC in order to evaluate them as replacements for more expensive Transparent Conducting Oxides (TCO's). Loss mechanisms in DSSC's due to SS mesh oxidation were quantified and protective coatings to prevent oxidation of SS mesh were developed. The second material which was evaluated for use as the top cell was copper zinc tin sulfide (CZTS). CZTS was deposited through a solution deposition route. Detailed investigations were done on the deposited films to understand the chemistry, crystal structure and its opto-electronic properties. Deposited CZTS films were found to be highly crystalline in direction. The films had a direct band gap of 1.5 eV with absorption coefficient greater than 104 cm -1 in agreement with published values. In the second part of the thesis detailed electrical and optical simulation models of the mechanical tandem solar cells were developed based on the most up-to-date materials physical constants available for each layer. The modeling was used to quantify

  17. Ultrastructural changes of cell walls under intense mechanical treatment of selective plant raw material

    International Nuclear Information System (INIS)

    Structural changes of cell walls under intense mechanical treatment of corn straw and oil-palm fibers were studied by electron and light microscopy. Differences in the character of destruction of plant biomass were revealed, and the dependence of destruction mechanisms on the structure of cell walls and lignin content was demonstrated. We suggest that the high reactivity of the particles of corn straw (about 18% of lignin) after intense mechanical treatment is related to disordering of cell walls and an increase of the surface area, while in the case of oil palm (10% of lignin) the major contribution into an increase in the reactivity is made by an increase of surface area. -- Highlights: ► Structure of cell walls determines the processes of plant materials' destruction. ► Ultrastructure of highly lignified materials strongly disordering by mechanical action. ► Ultrastructure of low-lignified materials is not disordering by mechanical action.

  18. Metal Phosphates as Proton Conducting Materials for Intermediate Temperature Fuel Cell and Electrolyser Applications

    DEFF Research Database (Denmark)

    Anfimova, Tatiana

    The present thesis presents the results achieved during my ph.d. project on a subject of intermediate temperature proton conducting metal phosphates as electrolyte materials for fuel cells and electrolysers. Fuel cells and electrolysers are electrochemical devices with high energy conversion...... with a proton conductivity of above 10-2S cm-1. Chapter 1 of the thesis is an introduction to basics of fuel cell and electrolyser technologies as well as proton conducting materials. Extended discussion on the proton conducting materials, a particularly phosphates is made in Chapter 2. Three major...... types of phosphates were systematically reviewed including solid acids or alkali hydrogen phosphates, pyrophosphates, and rare earth metal phosphates. Demonstration of the fuel cell technology based on solid acid proton conductor CsH2PO4 has inspired the active research in the area. Based on the...

  19. Pengaruh Variasi Kecepatan Stiring & Temperatur Sintering Terhadap Perubahan Struktur Mikro & Fase Material Sensor Gas Tio2

    Directory of Open Access Journals (Sweden)

    Della Dewi Ratnasari

    2014-03-01

    Full Text Available Penelitian material untuk sensor gas ini menggunakan bahan dasar TiO2 dan zat pelarut H2SO4 pekat 98% . Metode pembentuk sol-gel dilakukan dengan sampel di stiring menggunakan magnetic stirrer selama 2,5 jam, kecepatan 600, 700 dan 800 rpm dengan temperatur 200 º C hingga terbentuk gel. Drying dilakukan selama 1 jam dengan temperatur 350 º C, proses kalsinasi selama 1 jam temperatur 500 ºC. Proses selanjutnya serbuk TiO2 dikompaksi dengan tekanan 200 bar agar terbentuk padatan / pellet. Sintering dilakukan pada temperatur 700 ºC selama 1 jam. Karakterisasi material dilakukan dengan alat uji Scanning Electron microscope (SEM dan X-ray diffraction (XRD untuk menganalisa perubahan struktur mikro & fase material keramik TiO2. Berdasarkan hasil pengujian difraksi sinar–x (XRD, variasi stiring 600 rpm, 700 rpm & 800 rpm telah merubah fase anatase (raw material menjadi unstabil fase orthohombik (TiOSO4. Sintering pada temperatur 700 ͦ C telah menyebabkan unstabil fase TiOSO4 menjadi stabil fase TiO2 anatase. Sintesa sol-gel stiring 700 rpm dan 800 rpm dilanjutkan sintering 700 ͦ C menyebabkan reduksi kation Titanium. Berdasarkan hasil SEM, proses sol-gel dapat mereduksi raw material menjadi 130 nm pada kecepatan stiring 700 rpm temperatur operasi 200 ͦ C selama 150 menit.

  20. Evaluation of options for disposition of dispersible material in B-Cell

    International Nuclear Information System (INIS)

    The radioactive contaminants in the dispersible material in B-cell of the 324 Building Radiochemical Energy (RE) hot-cell complex at the Hanford Site in southeastern Washington exceed the allowable level. In 1986, there was a spill of 1.3 million curies of concentrated cesium and strontium in B-cell. Cleanup is required, and candidate technologies for cleaning up or otherwise addressing problems associated with the dispersible material are being evaluated by Pacific Northwest Laboratory (PNL). The RE hot-cell complex in 324 Building was constructed in the late 1950s. From the early 1960s until today the complex has been the site of numerous research, development, and demonstration programs using radioactive and hazardous materials. In mid-FY 1988, a program to clean B-cell was initiated. At present, dispersible material has been collected from 45% of the cell floor area, and 64% of the equipment and support racks have been removed from the cell. The evaluation of decontamination procedures are described

  1. Layered materials with improved magnesium intercalation for rechargeable magnesium ion cells

    Energy Technology Data Exchange (ETDEWEB)

    Doe, Robert Ellis; Downie, Craig Michael; Fischer, Christopher; Lane, George Hamilton; Morgan, Dane; Nevin, Josh; Ceder, Gerbrand; Persson, Kristin Aslaug; Eaglesham, David

    2016-07-26

    Electrochemical devices which incorporate cathode materials that include layered crystalline compounds for which a structural modification has been achieved which increases the diffusion rate of multi-valent ions into and out of the cathode materials. Examples in which the layer spacing of the layered electrode materials is modified to have a specific spacing range such that the spacing is optimal for diffusion of magnesium ions are presented. An electrochemical cell comprised of a positive intercalation electrode, a negative metal electrode, and a separator impregnated with a nonaqueous electrolyte solution containing multi-valent ions and arranged between the positive electrode and the negative electrode active material is described.

  2. Layered materials with improved magnesium intercalation for rechargeable magnesium ion cells

    Science.gov (United States)

    Doe, Robert Ellis; Downie, Craig Michael; Fischer, Christopher; Lane, George Hamilton; Morgan, Dane; Nevin, Josh; Ceder, Gerbrand; Persson, Kristin Aslaug; Eaglesham, David

    2015-10-27

    Electrochemical devices which incorporate cathode materials that include layered crystalline compounds for which a structural modification has been achieved which increases the diffusion rate of multi-valent ions into and out of the cathode materials. Examples in which the layer spacing of the layered electrode materials is modified to have a specific spacing range such that the spacing is optimal for diffusion of magnesium ions are presented. An electrochemical cell comprised of a positive intercalation electrode, a negative metal electrode, and a separator impregnated with a nonaqeuous electrolyte solution containing multi-valent ions and arranged between the positive electrode and the negative electrode active material is described.

  3. Layered materials with improved magnesium intercalation for rechargeable magnesium ion cells

    Energy Technology Data Exchange (ETDEWEB)

    Doe, Robert E.; Downie, Craig M.; Fischer, Christopher; Lane, George H.; Morgan, Dane; Nevin, Josh; Ceder, Gerbrand; Persson, Kristin A.; Eaglesham, David

    2016-01-19

    Electrochemical devices which incorporate cathode materials that include layered crystalline compounds for which a structural modification has been achieved which increases the diffusion rate of multi-valent ions into and out of the cathode materials. Examples in which the layer spacing of the layered electrode materials is modified to have a specific spacing range such that the spacing is optimal for diffusion of magnesium ions are presented. An electrochemical cell comprised of a positive intercalation electrode, a negative metal electrode, and a separator impregnated with a nonaqueous electrolyte solution containing multi-valent ions and arranged between the positive electrode and the negative electrode active material is described.

  4. Layered materials with improved magnesium intercalation for rechargeable magnesium ion cells

    Science.gov (United States)

    Doe, Robert Ellis; Downie, Craig Michael; Fischer, Christopher; Lane, George Hamilton; Morgan, Dane; Nevin, Josh; Cedar, Gerbrand; Persson, Kristin Aslaug; Eaglesham, David

    2015-11-05

    Electrochemical devices which incorporate cathode materials that include layered crystalline compounds for which a structural modification has been achieved which increases the diffusion rate of multi-valent ions into and out of the cathode materials. Examples in which the layer spacing of the layered electrode materials is modified to have a specific spacing range such that the spacing is optimal for diffusion of magnesium ions are presented. An electrochemical cell comprised of a positive intercalation electrode, a negative metal electrode, and a separator impregnated with a nonaqeuous electrolyte solution containing multi-valent ions and arranged between the positive electrode and the negative electrode active material is described.

  5. Anodized titania: Processing and characterization to improve cell-materials interactions for load bearing implants

    Science.gov (United States)

    Das, Kakoli

    The objective of this study is to investigate in vitro cell-materials interactions using human osteoblast cells on anodized titanium. Titanium is a bioinert material and, therefore, gets encapsulated after implantation into the living body by a fibrous tissue that isolates them from the surrounding tissues. In this work, bioactive nonporous and nanoporous TiO2 layers were grown on commercially pure titanium substrate by anodization process using different electrolyte solutions namely (1) H3PO 4, (2) HF and (3) H2SO4, (4) aqueous solution of citric acid, sodium fluoride and sulfuric acid. The first three electrolytes produced bioactive TiO2 films with a nonporous structure showing three distinctive surface morphologies. Nanoporous morphology was obtained on Ti-surfaces from the fourth electrolyte at 20V for 4h. Cross-sectional view of the nanoporous surface reveals titania nanotubes of length 600 nm. It was found that increasing anodization time initially increased the height of the nanotubes while maintaining the tubular array structure, but beyond 4h, growth of nanotubes decreased with a collapsed array structure. Human osteoblast (HOB) cell attachment and growth behavior were studied using an osteoprecursor cell line (OPC 1) for 3, 7 and 11 days. Colonization of the cells was noticed with distinctive cell-to-cell attachment on HF anodized surfaces. TiO2 layer grown in H2SO4 electrolyte did not show significant cell growth on the surface, and some cell death was also noticed. Good cellular adherence with extracellular matrix extensions in between the cells was noticed for samples anodized with H3PO 4 electrolyte and nanotube surface. Cell proliferation was excellent on anodized nanotube surfaces. An abundant amount of extracellular matrix (ECM) between the neighboring cells was also noticed on nanotube surfaces with filopodia extensions coming out from cells to grasp the nanoporous surface for anchorage. To better understand and compare cell-materials interactions

  6. Influence of the starting materials on performance of high temperature oxide fuel cells devices

    Directory of Open Access Journals (Sweden)

    Emília Satoshi Miyamaru Seo

    2004-03-01

    Full Text Available High temperature solid oxide fuel cells (SOFCs offer an environmentally friendly technology to convert gaseous fuels such as hydrogen, natural gas or gasified coal into electricity at high efficiencies. Besides the efficiency, higher than those obtained from the traditional energy conversion systems, a fuel cell provides many other advantages like reliability, modularity, fuel flexibility and very low levels of NOx and SOx emissions. The high operating temperature (950-1000 °C used by the current generation of the solid oxide fuel cells imposes severe constraints on materials selection in order to improve the lifetime of the cell. Besides the good electrical, electrochemical, mechanical and thermal properties, the individual cell components must be stable under the fuel cell operating atmospheres. Each material has to perform not only in its own right but also in conjunction with other system components. For this reason, each cell component must fulfill several different criteria. This paper reviews the materials and the methods used to fabricate the different cell components, such as the cathode, the electrolyte, the anode and the interconnect. Some remarkable results, obtained at IPEN (Nuclear Energy Research Institute in São Paulo, have been presented.

  7. Bone cell-materials interaction on alumina ceramics with different grain sizes

    International Nuclear Information System (INIS)

    The objective of this work was to study adhesion, proliferation and differentiation of osteoblast cells (OPC1) on alumina ceramic, a bio-inert material. Alumina ceramic with different average grain sizes, 1 μm and 12 μm, respectively, were used in as-prepared condition without any grinding and polishing to understand the influence of grain size on cell-material interactions. Scanning electron microscopy and confocal imaging were used to study attachment, adhesion and differentiation of OPC1 cells. Cells attached, proliferated and differentiated well on both the substrates. Adhesion of cells, as assessed by observing the production of vinculin, was found to be a consistent phenomenon on both the substrates. On day 5 of cell culture, significant cell-attachment was observed and vinculin was detected throughout cytoplasm. MTT assay showed that proliferation of OPC1 cells was consistently higher in the case of 12 μm-alumina. Cells of different morphology, nodular, plate-like as well as elongated, were found to get anchored at grains, grain boundaries as well as pores. On day 16, there were clear signs of mineralization as well. Over all, alumina with average grain size of 12 μm showed better cell-attachment, growth and differentiation compared to 1 μm grain size samples.

  8. Reactivation of X-irradiated cell material during limb regeneration in Urodeles Amphibians

    International Nuclear Information System (INIS)

    In amputated members irradiated with X-rays the regeneration power is inhibited. This power is restored by grafts of healthy tissue in the irradiated members. The origin of the cell material of the restored regeneration blastema has been studied by an original labelling technique. The different amounts of DNA in the graft cells and those of the stump mark the graft cells during the regeneration process. It was shown that the graft causes a reactivation of the inhibited stump cells and the reactivation stages are the same as the activation stages of the member regenerating normally. It was also established that during restored regeneration the cell material implanted in the irradiated members contributes, by the 160th day of regeneration, 4.5% of the cartilaginous regenerate cells and 12% of the muscle cells. All the other regenerate cells are supplied by the cells of the stump; these are reactivated and together with the activated graft cells lead to the restitution of the amputated member

  9. Fuel cells science and engineering. Materials, processes, systems and technology. Vol. 1

    Energy Technology Data Exchange (ETDEWEB)

    Stolten, Detlef; Emonts, Bernd (eds.) [Forschungszentrum Juelich GmbH (DE). Inst. fuer Energieforschung (IEF), Brennstoffzellen (IEF-3)

    2012-07-01

    The first volume is divided in four parts and 22 chapters. It is structured as follows: PART I: Technology. Chapter 1: Technical Advancement of Fuel-Cell Research and Development (Dr. Bernd Emonts, Ludger Blum, Thomas Grube, Werner Lehnert, Juergen Mergel, Martin Mueller and Ralf Peters); 2: Single-Chamber Fuel Cells (Teko W. Napporn and Melanie Kuhn); 3: Technology and Applications of Molten Carbonate Fuel Cells (Barbara Bosio, Elisabetta Arato and Paolo Greppi); 4: Alkaline Fuel Cells (Erich Guelzow); 5: Micro Fuel Cells (Ulf Groos and Dietmar Gerteisen); 6: Principles and Technology of Microbial Fuel Cells (Jan B. A. Arends, Joachim Desloover, Sebastia Puig and Willy Verstraete); 7: Micro-Reactors for Fuel Processing (Gunther Kolb); 8: Regenerative Fuel Cells (Martin Mueller). PART II: Materials and Production Processes. Chapter 9: Advances in Solid Oxide Fuel Cell Development between 1995 and 2010 at Forschungszentrum Juelich GmbH, Germany (Vincent Haanappel); 10: Solid Oxide Fuel Cell Electrode Fabrication by Infiltration (Evren Gunen); 11: Sealing Technology for Solid Oxide Fuel Cells (K. Scott Weil); 12: Phosphoric Acid, an Electrolyte for Fuel Cells - Temperature and Composition Dependence of Vapor Pressure and Proton Conductivity (Carsten Korte); 13: Materials and Coatings for Metallic Bipolar Plates in Polymer Electrolyte Membrane Fuel Cells (Heli Wang and John A. Turner); 14: Nanostructured Materials for Fuel Cells (John F. Elter); 15: Catalysis in Low-Temperature Fuel Cells - An Overview (Sabine Schimpf and Michael Bron). PART III: Analytics and Diagnostics. Chapter 16: Impedance Spectroscopy for High-Temperature Fuel Cells (Ellen Ivers-Tiffee, Andre Leonide, Helge Schichlein, Volker Sonn and Andre Weber); 17: Post-Test Characterization of Solid Oxide Fuel-Cell Stacks (Norbert H. Menzler and Peter Batfalsky); 18: In Situ Imaging at Large-Scale Facilities (Christian Toetzke, Ingo Manke and Werner Lehnert); 19: Analytics of Physical Properties of Low

  10. Promoted cell and material interaction on atmospheric pressure plasma treated titanium

    Energy Technology Data Exchange (ETDEWEB)

    Han, Inho [Convergence Technology Exam. Div. II, Korean Intellectual Patent Office, Daejeon (Korea, Republic of); Vagaska, Barbora [Cellbiocontrol Laboratory, Department of Medical Engineering, Yonsei University College of Medicine, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Seo, Hyok Jin [Cellbiocontrol Laboratory, Department of Medical Engineering, Yonsei University College of Medicine, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Kang, Jae Kyeong [Cellbiocontrol Laboratory, Department of Medical Engineering, Yonsei University College of Medicine, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Kwon, Byeong-Ju [Cellbiocontrol Laboratory, Department of Medical Engineering, Yonsei University College of Medicine, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Lee, Mi Hee [Cellbiocontrol Laboratory, Department of Medical Engineering, Yonsei University College of Medicine, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Park, Jong-Chul, E-mail: parkjc@yuhs.ac [Cellbiocontrol Laboratory, Department of Medical Engineering, Yonsei University College of Medicine, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-752 (Korea, Republic of)

    2012-03-01

    Surface carbon contamination is a natural phenomenon. However, it interferes with cell-biomaterial interaction. In order to eliminate the interference, atmospheric pressure plasma treatment was employed. Dielectric barrier discharge treatment of titanium surface for less than 10 min turned titanium super-hydrophilic. Adsorption of fibronectin which is the major cell adhesive protein increased after plasma treatment. Cell attachment parameters of osteoblast cells such as population, cell area, perimeter, Feret's diameter and cytoskeleton development were also enhanced. Cell proliferation increased on the plasma treated titanium. In conclusion, dielectric barrier discharge type atmospheric pressure plasma system is effective to modify titanium surface and the modified titanium promotes cell and material interactions.

  11. Characterization of thin-film silicon materials and solar cells through numerical modeling

    OpenAIRE

    Pieters, B.E.

    2008-01-01

    At present most commercially available solar cells are made of crystalline silicon (c-Si). The disadvantages of crystalline silicon solar cells are the high material cost and energy consumption during production. A cheaper alternative can be found in thin-film silicon solar cells. The thin-film silicon used in this type of solar cells is in a different phase than c-Si and usually alloyed with hydrogen. The most common thin-film silicon phases are hydrogenated amorphous silicon (a-Si:H) and hy...

  12. Host cell capable of producing enzymes useful for degradation of lignocellulosic material

    Science.gov (United States)

    Los, Alrik Pieter; Sagt, Cornelis Maria Jacobus; Schooneveld-Bergmans, Margot Elisabeth Francoise; Damveld, Robbertus Antonius

    2015-08-18

    The invention relates to a host cell comprising at least four different heterologous polynucleotides chosen from the group of polynucleotides encoding cellulases, hemicellulases and pectinases, wherein the host cell is capable of producing the at least four different enzymes chosen from the group of cellulases, hemicellulases and pectinases, wherein the host cell is a filamentous fungus and is capable of secretion of the at least four different enzymes. This host cell can suitably be used for the production of an enzyme composition that can be used in a process for the saccharification of cellulosic material.

  13. Effect of vertebroplasty filler materials on viability and gene expression of human nucleus pulposus cells.

    Science.gov (United States)

    Lazáry, Aron; Speer, Gábor; Varga, Péter Pál; Balla, Bernadett; Bácsi, Krisztián; Kósa, János P; Nagy, Zsolt; Takács, István; Lakatos, Péter

    2008-05-01

    Consequences of intradiscal cement leakage--often occurring after vertebral cement augmentation for the treatment of vertebral compression fractures--are still unknown. In this study, we have investigated the influences of vertebroplasty filler materials (polymethylmethacrylate-, calcium phosphate- and calcium sulfate-based bone cement) on isolated nucleus pulposus cells. Cell viability of cultured human nucleus pulposus cells were measured after treatment with vertebroplasty filler materials. Gene expression profile of selected genes was determined with quantitative real-time PCR. The widely used polymethylmethacrylate and calcium phosphate cement significantly decreased cell number in a dose- and time-dependent manner while calcium sulfate cement affected cell viability less. Expression of genes involved in matrix metabolism of nucleus pulposus--aggrecan, collagens, small proteoglycans--as well as important transcription factors have also significantly changed due to treatment (e.g., 2.5-fold decrease in aggrecan expression was determined in cultures due to polymethylmethacrylate treatment). Our results suggest that vertebroplasty filler materials--depending on the type of applied material--can accelerate the degeneration of nucleus pulposus cells resulting in a less flexible disc in case of intradiscal cement leakage. This process may increase the risk of a subsequent new vertebral fracture, the main complication of vertebral augmentation. PMID:18176942

  14. Li-Ion Pouch Cells for Vehicle Applications — Studies of Water Transmission and Packing Materials

    Directory of Open Access Journals (Sweden)

    Göran Flodberg

    2013-01-01

    Full Text Available This study includes analysis of encapsulation materials from lithium-ion pouch cells and water vapour transmission rate (WVTR measurements. WVTR measurements are performed on both fresh and environmentally stressed lithium-ion pouch cells. Capacity measurements are performed on both the fresh and the environmentally stressed battery cells to identify possible influences on electrochemical performance. Preparation of the battery cells prior to WVTR measurements includes opening of battery cells and extraction of electrode material, followed by resealing the encapsulations and adhesively mounting of gas couplings. A model describing the water diffusion through the thermal welds of the encapsulation are set up based on material analysis of the encapsulation material. Two WVTR equipments with different type of detectors are evaluated in this study. The results from the WVTR measurements show how important it is to perform this type of studies in dry environment and apply a rigorous precondition sequence before testing. Results from modelling confirm that the WVTR method has potential to be used for measurements of water diffusion into lithium-ion pouch cells. Consequently, WVTR measurements should be possible to use as a complement or alternative method to for example Karl Fisher titration.

  15. FUNDAMENTAL STUDIES OF THE DURABILITY OF MATERIALS FOR INTERCONNECTS IN SOLID OXIDE FUEL CELLS

    Energy Technology Data Exchange (ETDEWEB)

    Frederick S. Pettit; Gerald H. Meier

    2003-06-30

    This report describes the result of the first eight months of effort on a project directed at improving metallic interconnect materials for solid oxide fuel cells (SOFCs). The results include cyclic oxidation studies of a group of ferritic alloys, which are candidate interconnect materials. The exposures have been carried out in simulated fuel cell atmospheres. The oxidation morphologies have been characterized and the ASR has been measured for the oxide scales. The effect of fuel cell electric current density on chromia growth rates has been considered The thermomechanical behavior of the scales has been investigated by stress measurements using x-ray diffraction and interfacial fracture toughness measurements using indentation. The ultimate goal of this thrust is to use knowledge of changes in oxide thickness, stress and adhesion to develop accelerated testing methods for evaluating SOFC interconnect alloys. Finally a theoretical assessment of the potential for use of ''new'' metallic materials as interconnect materials has been conducted and is presented in this report. Alloys being considered include materials based on pure nickel, materials based on the ''Invar'' concept, and coated materials to optimize properties in both the anode and cathode gases.

  16. Invitro study of adherent mandibular osteoblast-like cells on carrier materials.

    Science.gov (United States)

    Turhani, D; Weissenböck, M; Watzinger, E; Yerit, K; Cvikl, B; Ewers, R; Thurnher, D

    2005-07-01

    Augmentation of the craniofacial region is necessary for many aesthetic and reconstructive procedures. Tissue engineering offers a new option to supplement existing treatment regimens. In this procedure, materials composed of hydroxyapatite (HA), of synthetic or natural origin, are used as scaffolds. The aim of this study was to evaluate the effects of three HA materials on cultured human osteoblasts in vitro. Explant cultures of cells from human alveolar bone were established. Human osteoblasts were cultured on the surface of HA calcified from red algae (C GRAFT/Algipore), deproteinized bovine HA (Bio-Oss) and bovine HA carrying the cell binding peptide P-15 (Pep Gen P-15). Cultured cells were evaluated with respect to cell attachment, proliferation and differentiation. Cells were cultured for 6 and 21 days under osteogenic differentiation conditions, and tissue-culture polystyrene dishes were used as control. The ability of cells to proliferate and form extracellular matrix on these scaffolds was assessed by a DNA quantification assay, protein synthesis analysis and by scanning electron microscopical examination. Osteogenic differentiation was screened by the expression of alkaline phosphatase. The osteoblastic phenotype of the cells was monitored using mRNA levels of the bone-related proteins including osteocalcin, osteopontin and collagen Type I. We found that cells cultured on C GRAFT/Algipore) and Pep Gen P-15 showed a continuous increase in DNA content and protein synthesis. Cells cultured on Bio-Oss showed a decrease in DNA content from Day 6 (P culture period. The results of our in vitro study show that the differences in metabolic activity of cells grown on HA materials are directly related to the substrate on which they are grown. They confirm the excellent properties of HA carrying the cell binding peptide P-15 and HA calcified from red algae as used in maxillofacial surgery procedures. PMID:16053876

  17. Fumed silica nanoparticle mediated biomimicry for optimal cell-material interactions for artificial organ development.

    Science.gov (United States)

    de Mel, Achala; Ramesh, Bala; Scurr, David J; Alexander, Morgan R; Hamilton, George; Birchall, Martin; Seifalian, Alexander M

    2014-03-01

    Replacement of irreversibly damaged organs due to chronic disease, with suitable tissue engineered implants is now a familiar area of interest to clinicians and multidisciplinary scientists. Ideal tissue engineering approaches require scaffolds to be tailor made to mimic physiological environments of interest with specific surface topographical and biological properties for optimal cell-material interactions. This study demonstrates a single-step procedure for inducing biomimicry in a novel nanocomposite base material scaffold, to re-create the extracellular matrix, which is required for stem cell integration and differentiation to mature cells. Fumed silica nanoparticle mediated procedure of scaffold functionalization, can be potentially adapted with multiple bioactive molecules to induce cellular biomimicry, in the development human organs. The proposed nanocomposite materials already in patients for number of implants, including world first synthetic trachea, tear ducts and vascular bypass graft. PMID:24243739

  18. Differential Effects of Coating Materials on Viability and Migration of Schwann Cells

    Directory of Open Access Journals (Sweden)

    Silvan Klein

    2016-03-01

    Full Text Available Synthetic nerve conduits have emerged as an alternative to guide axonal regeneration in peripheral nerve gap injuries. Migration of Schwann cells (SC from nerve stumps has been demonstrated as one essential factor for nerve regeneration in nerve defects. In this experiment, SC viability and migration were investigated for various materials to determine the optimal conditions for nerve regeneration. Cell viability and SC migration assays were conducted for collagen I, laminin, fibronectin, lysine and ornithine. The highest values for cell viability were detected for collagen I, whereas fibronectin was most stimulatory for SC migration. At this time, clinically approved conduits are based on single-material structures. In contrast, the results of this experiment suggest that material compounds such as collagen I in conjunction with fibronectin should be considered for optimal nerve healing.

  19. Laser annealing of amorphous/poly: Silicon solar cell material flight experiment

    Science.gov (United States)

    Cole, Eric E.

    1990-01-01

    The preliminary design proposed for the microelectronics materials processing equipment is presented. An overall mission profile, description of all processing steps, analysis methods and measurement techniques, data acquisition and storage, and a preview of the experimental hardware are included. The goal of the project is to investigate the viability of material processing of semiconductor microelectronics materials in a micro-gravity environment. The two key processes are examined: (1) Rapid Thermal Annealing (RTA) of semiconductor thin films and damaged solar cells, and (2) thin film deposition using a filament evaporator. The RTA process will be used to obtain higher quality crystalline properties from amorphous/poly-silicon films. RTA methods can also be used to repair radiation-damaged solar cells. On earth this technique is commonly used to anneal semiconductor films after ion-implantation. The damage to the crystal lattice is similar to the defects found in solar cells which have been exposed to high-energy particle bombardment.

  20. Fabrication and Characterizations of Materials and Components for Intermediate Temperature Fuel Cells and Water Electrolysers

    DEFF Research Database (Denmark)

    Jensen, Annemette Hindhede; Prag, Carsten Brorson; Li, Qingfeng;

    The worldwide development of fuel cells and electrolysers has so far almost exclusively addressed either the low temperature window (20-200 °C) or the high temperature window (600-1000 °C). This work concerns the development of key materials and components of a new generation of fuel cells and...... electrolysers for operation in the intermediate temperature range from 200 to 400 °C. The intermediate temperature interval is of importance for the use of renewable fuels. Furthermore electrode kinetics is significantly enhanced compared to when operating at low temperature. Thus non-noble metal catalysts...... might be used. One of the key materials in the fuel cell and electrolyser systems is the electrolyte. Proton conducting materials such as cesium hydrogen phosphates, zirconium hydrogen phosphates and tin pyrophosphates have been investigated by others and have shown interesting potential....

  1. A Review of Metallic Bipolar Plates for Proton Exchange Membrane Fuel Cells: Materials and Fabrication Methods

    Directory of Open Access Journals (Sweden)

    Shahram Karimi

    2012-01-01

    Full Text Available The proton exchange membrane fuel cell offers an exceptional potential for a clean, efficient, and reliable power source. The bipolar plate is a key component in this device, as it connects each cell electrically, supplies reactant gases to both anode and cathode, and removes reaction products from the cell. Bipolar plates have been fabricated primarily from high-density graphite, but in recent years, much attention has been paid to developing cost-effective and feasible alternative materials. Two different classes of materials have attracted attention: metals and composites. This paper offers a comprehensive review of the current research being carried out on metallic bipolar plates, covering materials and fabrication methods.

  2. Nanomaterials for Polymer Electrolyte Membrane Fuel Cells; Materials Challenges Facing Electrical Energy Storate

    Energy Technology Data Exchange (ETDEWEB)

    Gopal Rao, MRS Web-Editor; Yury Gogotsi, Drexel University; Karen Swider-Lyons, Naval Research Laboratory

    2010-08-05

    Symposium T: Nanomaterials for Polymer Electrolyte Membrane Fuel Cells Polymer electrolyte membrane (PEM) fuel cells are under intense investigation worldwide for applications ranging from transportation to portable power. The purpose of this seminar is to focus on the nanomaterials and nanostructures inherent to polymer fuel cells. Symposium topics will range from high-activity cathode and anode catalysts, to theory and new analytical methods. Symposium U: Materials Challenges Facing Electrical Energy Storage Electricity, which can be generated in a variety of ways, offers a great potential for meeting future energy demands as a clean and efficient energy source. However, the use of electricity generated from renewable sources, such as wind or sunlight, requires efficient electrical energy storage. This symposium will cover the latest material developments for batteries, advanced capacitors, and related technologies, with a focus on new or emerging materials science challenges.

  3. Naturally derived materials-based cell and drug delivery systems in skin regeneration.

    Science.gov (United States)

    Huang, Sha; Fu, Xiaobing

    2010-03-01

    The objective of regenerative medicine is to provide cells with a local environment of artificial extracellular matrix where they can proliferate and differentiate efficiently and therefore, induce the repair of defective tissues according to the natural healing potential of patients. For this purpose, naturally derived materials are being widely used because of their similarities to the extracellular matrix, typically good biocharacteristics and inherent cellular interaction. Also, natural polymers can be engineered to release growth factors and related agents in response to physiologic signals to imitate the natural healing process and to promote fast tissue regeneration and reduce scarring in wounds. Although synthetic materials have been used extensively in tissue engineering fields, this review illustrates the contribution of natural materials and natural materials-based protein delivery systems to regenerative medicine research, with emphasis on the application of multifunctional vehicles for cell and growth factor delivery in skin regeneration research. PMID:19850093

  4. Heat Shield Employing Cured Thermal Protection Material Blocks Bonded in a Large-Cell Honeycomb Matrix

    Science.gov (United States)

    Zell, Peter

    2012-01-01

    A document describes a new way to integrate thermal protection materials on external surfaces of vehicles that experience the severe heating environments of atmospheric entry from space. Cured blocks of thermal protection materials are bonded into a compatible, large-cell honeycomb matrix that can be applied on the external surfaces of the vehicles. The honeycomb matrix cell size, and corresponding thermal protection material block size, is envisioned to be between 1 and 4 in. (.2.5 and 10 cm) on a side, with a depth required to protect the vehicle. The cell wall thickness is thin, between 0.01 and 0.10 in. (.0.025 and 0.25 cm). A key feature is that the honeycomb matrix is attached to the vehicle fs unprotected external surface prior to insertion of the thermal protection material blocks. The attachment integrity of the honeycomb can then be confirmed over the full range of temperature and loads that the vehicle will experience. Another key feature of the innovation is the use of uniform-sized thermal protection material blocks. This feature allows for the mass production of these blocks at a size that is convenient for quality control inspection. The honeycomb that receives the blocks must have cells with a compatible set of internal dimensions. The innovation involves the use of a faceted subsurface under the honeycomb. This provides a predictable surface with perpendicular cell walls for the majority of the blocks. Some cells will have positive tapers to accommodate mitered joints between honeycomb panels on each facet of the subsurface. These tapered cells have dimensions that may fall within the boundaries of the uniform-sized blocks.

  5. Polymer Solar Cells – Non Toxic Processing and Stable Polymer Photovoltaic Materials

    DEFF Research Database (Denmark)

    Søndergaard, Roar

    2012-01-01

    The field of polymer solar cell has experienced enormous progress in the previous years, with efficiencies of small scale devices (~1 mm2) now exceeding 8%. However, if the polymer solar cell is to achieve success as a renewable energy resource, mass production of sufficiently stable and efficient...... development of more stable materials. The field of polymer solar cells has evolved around the use of toxic and carcinogenic solvents like chloroform, benzene, toluene, chlorobenzene, dichlorobenzene and xylene. As large scale production of organic solar cells is envisaged to production volumes corresponding...... solar cells as it slows down diffusion though the active layer, but just as important it renders the layer insoluble. This allows for further processing, using the same solvent, without dissolving already processed layers, and resulted in the first ever reported solar cells where all layers are...

  6. Influence of Microstructure and Sintering Routes on Transport Properties of Apatite Materials for Fuel Cells

    Institute of Scientific and Technical Information of China (English)

    A.Chesnaud; C.Estournes; G.Dezannau

    2007-01-01

    1 Results Oxy-apatite materials are thought as zirconia-substitutes in Solid Oxide Fuel Cells due to their fast ionic conduction. However, the well known difficulties related to their densification prevent them from being used as such. This study presents strategies to obtain oxy-apatite dense materials and the influence of elaboration route on transport properties. Particular emphasis is put on the microstructure effect on ion conduction. By the combined use of freeze-drying and conventional or spark p...

  7. Solution-processed cathode interfacial layer materials for high-efficiency polymer solar cells

    OpenAIRE

    Biao Xiao; Hongbin Wu; Yong Cao

    2015-01-01

    Polymer solar cells (PSCs) are a new type of renewable energy source currently being extensively investigated due to perceived advantages; such as being lightweight, low-cost and because of the unlimited materials resource. The power conversion efficiency of state-of-the-art PSCs has increased dramatically in the past few years, obtained mainly through the development of new electron donor polymers, acceptors, and novel device structures through the use of various electrode interfacial materi...

  8. Micro-Computed Tomography and Finite Element Method Study of Open-Cell Porous Materials

    OpenAIRE

    Wejrzanowski Tomasz; Skibinski Jakub; Cwieka Karol; Kurzydlowski Krzysztof J.

    2015-01-01

    In the present paper the characterization of structure and properties of open-cell porous materials by high-resolution x-ray micro-computed tomography (μCT) and finite element method (FEM) is addressed. The unique properties of open porosity foams make them interesting in a range of applications in science and engineering such as energy absorbers, lightweight construction materials or heat insulators. Consequently, a detailed knowledge of structure as well as mechanical properties (i.e. Young...

  9. Manufacture of ribbon and solar cells of material of semiconductor grade

    International Nuclear Information System (INIS)

    A method is described of producing ribbon-like substantially monocrystalline bodies of silicon or other materials of semiconductor grade suitable for use in solar cells or other semiconductor devices. A tube of the material is made and a photovoltaic junction formed in it. The tube is then divided lengthwise into a number of ribbon-like bodies. The photovoltaic junction can be formed either by diffusion or by ion-implantation. (U.K.)

  10. Work plan for testing silicone impression material and fixture on pool cell capsule

    International Nuclear Information System (INIS)

    The purpose of this work plan is to provide a safe procedure to test a cesium capsule impression fixture at Waste Encapsulation and Storage Facility (WESF). The impression will be taken with silicone dental impression material pressed down upon the capsule using the impression fixture. This test will evaluate the performance of the fixture and impression material under high radiation and temperature conditions on a capsule in a WESF pool cell

  11. Radiation shielding test for hot cells of Irradiated Material Examination Facility(IMEF)

    International Nuclear Information System (INIS)

    Radiation shielding test for IMEF(Irradiated Material Examination Facility) hot cell walls was executed using two Co 60 sources with the activities of 1,600 Ci and 30 Ci respectively. The tested walls are made of heavy concrete or lead, with the maximum thickness of 1,200 mm for concrete cell and 200 mm for lead cell. At first, we measured the dose rates for several standard walls and the result was used as standard reference. We also measured dose rates for hot cell walls by the same method and compared with reference. The number of testing points are 6,000 and we found out defect for several points which are mostly located in boundaries between embedded material and concrete. The defective areas were re tested after repaired and results for the areas were acceptable

  12. Highly efficient organic multi-junction solar cells with a thiophene based donor material

    Energy Technology Data Exchange (ETDEWEB)

    Meerheim, Rico, E-mail: rico.meerheim@iapp.de; Körner, Christian; Leo, Karl, E-mail: karl.leo@iapp.de [Institut für Angewandte Photophysik, Technische Universität Dresden, George-Bähr-Straße 1, 01062 Dresden (Germany)

    2014-08-11

    The efficiency of organic solar cells can be increased by serial stacked subcells even upon using the same absorber material. For the multi-junction devices presented here, we use the small molecule donor material DCV5T-Me. The subcell currents were matched by optical transfer matrix simulation, allowing an efficiency increase from 8.3% for a single junction up to 9.7% for a triple junction cell. The external quantum efficiency of the subcells, measured under appropriate light bias illumination, is spectrally shifted due to the microcavity of the complete stack, resulting in a broadband response and an increased cell current. The increase of the power conversion efficiency upon device stacking is even stronger for large area cells due to higher influence of the resistance of the indium tin oxide anode, emphasizing the advantage of multi-junction devices for large-area applications.

  13. Highly efficient organic multi-junction solar cells with a thiophene based donor material

    International Nuclear Information System (INIS)

    The efficiency of organic solar cells can be increased by serial stacked subcells even upon using the same absorber material. For the multi-junction devices presented here, we use the small molecule donor material DCV5T-Me. The subcell currents were matched by optical transfer matrix simulation, allowing an efficiency increase from 8.3% for a single junction up to 9.7% for a triple junction cell. The external quantum efficiency of the subcells, measured under appropriate light bias illumination, is spectrally shifted due to the microcavity of the complete stack, resulting in a broadband response and an increased cell current. The increase of the power conversion efficiency upon device stacking is even stronger for large area cells due to higher influence of the resistance of the indium tin oxide anode, emphasizing the advantage of multi-junction devices for large-area applications

  14. Spatial Patterning of Newly-Inserted Material during Bacterial Cell Growth

    Science.gov (United States)

    Ursell, Tristan

    2012-02-01

    In the life cycle of a bacterium, rudimentary microscopy demonstrates that cell growth and elongation are essential characteristics of cellular reproduction. The peptidoglycan cell wall is the main load-bearing structure that determines both cell shape and overall size. However, simple imaging of cellular growth gives no indication of the spatial patterning nor mechanism by which material is being incorporated into the pre-existing cell wall. We employ a combination of high-resolution pulse-chase fluorescence microscopy, 3D computational microscopy, and detailed mechanistic simulations to explore how spatial patterning results in uniform growth and maintenance of cell shape. We show that growth is happening in discrete bursts randomly distributed over the cell surface, with a well-defined mean size and average rate. We further use these techniques to explore the effects of division and cell wall disrupting antibiotics, like cephalexin and A22, respectively, on the patterning of cell wall growth in E. coli. Finally, we explore the spatial correlation between presence of the bacterial actin-like cytoskeletal protein, MreB, and local cell wall growth. Together these techniques form a powerful method for exploring the detailed dynamics and involvement of antibiotics and cell wall-associated proteins in bacterial cell growth.[4pt] In collaboration with Kerwyn Huang, Stanford University.

  15. Curcumin-loaded silica-based mesoporous materials: Synthesis, characterization and cytotoxic properties against cancer cells.

    Science.gov (United States)

    Bollu, Vishnu Sravan; Barui, Ayan Kumar; Mondal, Sujan Kumar; Prashar, Sanjiv; Fajardo, Mariano; Briones, David; Rodríguez-Diéguez, Antonio; Patra, Chitta Ranjan; Gómez-Ruiz, Santiago

    2016-06-01

    Two different silica based (MSU-2 and MCM-41) curcumin loaded mesoporous materials V3 and V6 were synthesized and characterized by several physico-chemical techniques. Release kinetic study revealed the slow and sustained release of curcumin from those materials in blood simulated fluid (pH: 7.4). The materials V3 and V6 were found to be biocompatible in non-cancerous CHO cell line while exhibiting significant cytotoxicity in different cancer cells (human lung carcinoma cells: A549, human breast cancer cells: MCF-7, mouse melanoma cells: B16F10) compared to pristine curcumin indicating the efficacy of the mesoporous silica materials based drug delivery systems (DDSs). The generation of intracellular reactive oxygen species (ROS) and down regulation of anti-apoptotic protein leading to the induction of apoptosis were found to be the plausible mechanisms behind the anti-cancer activity of these DDSs. These results suggest that curcumin-loaded drug delivery system may be successfully employed as an alternative treatment strategy for cancer therapeutics through a nanomedicine approach in near future. PMID:27040234

  16. Enhanced cell adhesion to silicone implant material through plasma surface modification.

    Science.gov (United States)

    Hauser, J; Zietlow, J; Köller, M; Esenwein, S A; Halfmann, H; Awakowicz, P; Steinau, H U

    2009-12-01

    Silicone implant material is widely used in the field of plastic surgery. Despite its benefits the lack of biocompatibility this material still represents a major problem. Due to the surface characteristics of silicone, protein adsorption and cell adhesion on this polymeric material is rather low. The aim of this study was to create a stable collagen I surface coating on silicone implants via glow-discharge plasma treatment in order to enhance cell affinity and biocompatibility of the material. Non-plasma treated, collagen coated and conventional silicone samples (non-plasma treated, non-coated) served as controls. After plasma treatment the change of surface free energy was evaluated by drop-shape analysis. The quality of the collagen coating was analysed by electron microscopy and Time-Of-Flight Secondary Ion Mass Spectrometry. For biocompatibility tests mouse fibroblasts 3T3 were cultivated on the different silicone surfaces and stained with calcein-AM and propidium iodine to evaluate cell viability and adherence. Analysis of the different surfaces revealed a significant increase in surface free energy after plasma pre-treatment. As a consequence, collagen coating could only be achieved on the plasma activated silicone samples. The in vitro tests showed that the collagen coating led to a significant increase in cell adhesion and cell viability. PMID:19641852

  17. Improved methods for binding acma-type protein anchor fusions yo cell-wall material of micro-organisms

    NARCIS (Netherlands)

    Leenhouts, Cornelis; Ramasamy, R.; Steen, Anton; Kok, Jan; Buist, Girbe; Kuipers, Oscar

    2002-01-01

    The invention provides a method for improving binding of a proteinaceous substance to cell-wall material of a Gram-positive bacterium, said substance comprising an AcmA cell wall binding domain or homolog or functional derivative thereof, said method comprising treating said cell-wall material with

  18. Comparison of silicon oxide and silicon carbide absorber materials in silicon thin-film solar cells

    OpenAIRE

    Walder Cordula; Kellermann Martin; Wendler Elke; Rensberg Jura; von Maydell Karsten; Agert Carsten

    2015-01-01

    Since solar energy conversion by photovoltaics is most efficient for photon energies at the bandgap of the absorbing material the idea of combining absorber layers with different bandgaps in a multijunction cell has become popular. In silicon thin-film photovoltaics a multijunction stack with more than two subcells requires a high bandgap amorphous silicon alloy top cell absorber to achieve an optimal bandgap combination. We address the question whether amorphous silicon carbide (a-SiC:H) or ...

  19. Design of solar cell materials via soft X-ray spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Himpsel, F.J., E-mail: fhimpsel@wisc.edu [Department of Physics, University of Wisconsin Madison, Madison, WI 53706 (United States); Cook, P.L. [Natural Sciences Department, University of Wisconsin Superior, Superior, WI 54880 (United States); Torre, G. de la [Departamento de Química Orgánica, Facultad de Ciencias, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049 Madrid (Spain); Garcia-Lastra, J.M. [Material Physics Center (MPC), Centro de Física de Materiales (CSIC-UPV/EHU), Donostia International Physics Center - DIPC, Departamento de Fisica Aplicada I, Universidad del Pais Vasco, 20018 San Sebastian (Spain); Department of Physics, Center for Atomic-scale Materials Design, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark); Gonzalez-Moreno, R. [Material Physics Center (MPC), Centro de Física de Materiales (CSIC-UPV/EHU), Donostia International Physics Center - DIPC, Departamento de Fisica Aplicada I, Universidad del Pais Vasco, 20018 San Sebastian (Spain); Guo, J.-H. [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Hamers, R.J. [Department of Chemistry, University of Wisconsin Madison, Madison, WI 53706 (United States); Kronawitter, C.X. [Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Johnson, P.S. [Department of Physics, University of Wisconsin Madison, Madison, WI 53706 (United States); Ortega, J.E.; Pickup, D. [Material Physics Center (MPC), Centro de Física de Materiales (CSIC-UPV/EHU), Donostia International Physics Center - DIPC, Departamento de Fisica Aplicada I, Universidad del Pais Vasco, 20018 San Sebastian (Spain); and others

    2013-10-15

    Highlights: ► The use of soft X-ray spectroscopy for developing new materials for solar cells is illustrated. ► A generic layout of a solar cell is given, which facilitates the discussion of the energy levels involved in a solar cell and their optimization. ► Systematic measurements of organometallic dyes are presented in combination with density functional theory. ► The data reveal trends that are useful for tailoring materials for solar cells. ► A solar cell design based on thin film p-type diamond as donor is used as example. -- Abstract: This overview illustrates how spectroscopy with soft X-rays can assist the development of new materials and new designs for solar cells. The starting point is the general layout of a solar cell, which consists of a light absorber sandwiched between an electron donor and an electron acceptor. There are four relevant energy levels that can be measured with a combination of X-ray absorption spectroscopy and photoelectron spectroscopy, as illustrated for an organic dye as absorber attached to a p-doped diamond film as donor. Systematic measurements of organometallic dyes (phthalocyanines and porphyrins) as a function of the metal atom are presented for the metal 2p and N 1s absorption edges. In combination with density functional theory one can discern trends that are useful for tailoring absorber molecules. A customized porphyrin molecule is investigated that combines an absorber with a donor and a linker to an oxide acceptor. The bridge to device fabrication is crossed by correlating spectroscopic features with the photocurrent in hematite photoanodes for water splitting. For speeding up the development of new materials and designs of solar cells a feedback loop between spectroscopy, theory, synthesis and device fabrication is envisioned.

  20. Material- and feature-dependent effects on cell adhesion to micro injection moulded medical polymers.

    Science.gov (United States)

    Choi, Seong Ying; Habimana, Olivier; Flood, Peter; Reynaud, Emmanuel G; Rodriguez, Brian J; Zhang, Nan; Casey, Eoin; Gilchrist, Michael D

    2016-09-01

    Two polymers, polymethylmethacrylate (PMMA) and cyclic olefin copolymer (COC), containing a range of nano- to micron- roughness surfaces (Ra 0.01, 0.1, 0.4, 1.0, 2.0, 3.2 and 5.0μm) were fabricated using electrical discharge machining (EDM) and replicated using micro injection moulding (μIM). Polymer samples were characterized using optical profilometry, atomic force microscopy (AFM) and water surface contact angle. Cell adhesion tests were carried out using bacterial Pseudomonas fluorescens and mammalian Madin-Darby Canine Kidney (MDCK) cells to determine the effect of surface hydrophobicity, surface roughness and stiffness. It is found that there are features which gave insignificant differences (feature-dependent effect) in cell adhesion, albeit a significant difference in the physicochemical properties (material-dependent effect) of substrata. In bacterial cell adhesion, the strongest feature-dependence is found at Ra 0.4μm surfaces, with material-dependent effects strongest at Ra 0.01μm. Ra 0.1μm surfaces exhibited strongest feature-dependent effects and Ra 5.0μm has strongest material-dependent effects on mammalian cell adhesion. Bacterial cell adhesion is found to be favourable to hydrophobic surfaces (COC), with the lowest adhesion at Ra 0.4μm for both materials. Mammalian cell adhesion is lowest in Ra 0.1μm and highest in Ra 1.0μm, and generally favours hydrophilic surfaces (PMMA). These findings can be used as a basis for developing medical implants or microfluidic devices using micro injection moulding for diagnostic purposes, by tuning the cell adhesion on different areas containing different surface roughnesses on the diagnostic microfluidic devices or medical implants. PMID:27137802

  1. Cell response of calcium phosphate based ceramics, a bone substitute material

    Directory of Open Access Journals (Sweden)

    Juliana Marchi

    2013-01-01

    Full Text Available The aim of this study was to characterize calcium phosphate ceramics with different Ca/P ratios and evaluate cell response of these materials for use as a bone substitute. Bioceramics consisting of mixtures of hydroxyapatite (HAp and β-tricalcium phosphate (β-TCP powders in different proportions were pressed and sintered. The physical and chemical properties of these bioceramics were then characterized. Characterization of the biological properties of these materials was based on analysis of cell response using cultured fibroblasts. The number of cells attached to the samples was counted from SEM images of samples exposed to cell culture solution for different periods. These data were compared by analysis of variance (ANOVA complemented by the Tukey's test. The TCP sample had higher surface roughness and lower density. The adherence and growth of FMM1 cells on samples from all groups was studied. Even though the different calcium based ceramics exhibited properties which made them suitable as bone substitutes, those with higher levels of β-TCP revealed improved cell growth on their surfaces. These observations indicated two-phase calcium phosphate based materials with a β-TCP surface layer to be a promising bone substitute.

  2. Molybdate Based Ceramic Negative-Electrode Materials for Solid Oxide Cells

    DEFF Research Database (Denmark)

    Graves, Christopher R.; Reddy Sudireddy, Bhaskar; Mogensen, Mogens Bjerg

    2010-01-01

    Novel molybdate materials with varying Mo valence were synthesized as possible negative-electrode materials for solid oxide cells. The phase, stability, microstructure and electrical conductivity were characterized. The electrochemical activity for H2O and CO2 reduction and H2 and CO oxidation was...... enhanced the electrocatalytic activity and electronic conductivity. The polarization resistances of the best molybdates were two orders of magnitude lower than that of donor-doped strontium titanates. Many of the molybdate materials were significantly activated by cathodic polarization, and they exhibited...

  3. Self-assembled photosynthesis-inspired light harvesting material and solar cells containing the same

    Science.gov (United States)

    Lindsey, Jonathan S.; Chinnasamy, Muthiah; Fan, Dazhong

    2009-12-15

    A solar cell is described that comprises: (a) a semiconductor charge separation material; (b) at least one electrode connected to the charge separation material; and (c) a light-harvesting film on the charge separation material, the light-harvesting film comprising non-covalently coupled, self-assembled units of porphyrinic macrocycles. The porphyrinic macrocycles preferably comprise: (i) an intramolecularly coordinated metal; (ii) a first coordinating substituent; and (iii) a second coordinating substituent opposite the first coordinating substituent. The porphyrinic macrocycles can be assembled by repeating intermolecular coordination complexes of the metal, the first coordinating substituent and the second coordinating substituent.

  4. Materials and Components for Low Temperature Solid Oxide Fuel Cells – an Overview

    OpenAIRE

    Radhika, D; A. S. Nesaraj

    2013-01-01

    This article summarizes the recent advancements made in the area of materials and components for low temperature solid oxide fuel cells (LT-SOFCs). LT-SOFC is a new trend in SOFCtechnology since high temperature SOFC puts very high demands on the materials and too expensive to match marketability. The current status of the electrolyte and electrode materials used in SOFCs, their specific features and the need for utilizing them for LT-SOFC are presented precisely in this review article. The s...

  5. Synthesis and Characterization of Nanostructured Cathode Material (BSCF) for Solid Oxide Fuel Cells

    OpenAIRE

    Darab, Mahdi

    2009-01-01

    This thesis focuses on developing an appropriate cathode material throughnanotechnology as a key component for a promising alternative of renewable energygenerating systems, Intermediate Temperature Solid Oxide Fuel Cells (IT-SOFC).Aiming at a working cathode material for IT-SOFC, a recently reported capable oxideperovskite material has been synthesized through two different chemical methods.BaxSr1-xCoyFe1-yO3−δ (BSCF) with y =0.8 and x =0.2 was fabricated in nanocrystallineform by a novel ch...

  6. Pengaruh Variasi Kadar Zn Dan Temperatur Hydrotermal Terhadap Struktur Dan Nilai Konduktivitas Elektrik Material Graphene

    Directory of Open Access Journals (Sweden)

    Lita Nur Azizah

    2014-09-01

    Full Text Available Graphene adalah bentuk 2D dari karbon dengan sifat-sifat unggul yang menarik untuk dikembangkan. Permasalahan yang kemudian muncul adalah proses sintesis massal yang masih menjadi kendala. Penelitian ini bertujuan untuk mensintesis material graphene secara kimiawi dengan menggunakan reduktor zinc dan metode hydrothermal dan menganalisa pengaruh varaiasi penambahan massa sebesar 0,8 gram, 1,6 gram, dan 2,4 gram zinc serta variasi temperatur hydrthermal 160ᵒC, 180ᵒC, 200ᵒC. Proses karakterisasi material graphene dilakukan dengan pengujian Scanning Electron Microscope (SEM, X-Ray Diffraction (XRD, Fourier Transform Infrared spectroscopy, Uji Iodine number, dan Four Point Probe digunakan untuk mengetahui nilai konduktivitas elektrik material. Morfologi dari graphene yang dihasilkan berbentuk lembaran-lembaran transparan dan disertai dengan kerutan pada permukaannya. Nilai konduktivitas elektrik terbesar dihasilkan dari variasi panambahan serbuk zinc sebesar 0,8 gram dan temperatur hydrothermal sebesar 200ᵒC dengan nilai sebesar 0,10281 S/cm dan bilangan iodine 11384,64.

  7. Environment-oriented life cycle analysis of bulk materials, applied in solar cell systems

    International Nuclear Information System (INIS)

    In the solar cell technology several bulk materials (glass, steel, aluminium, concrete, copper, zinc and synthetic materials) are applied intensively. By means of a life cycle analysis (LCA) the environmental effects and bottlenecks of the use of these materials is investigated in this report. Also attention is paid to the options to reduce the environmental effects of photovoltaic (PV) systems by changing processes and/or by redesign of the PV systems. Two systems are studied: solar cells, integrated in pitched roofs, and solar cells on the ground in solar cell arrays. The study is focused on the use of bulk materials in the solar module, the cables and the supporting construction. After brief introductions on the environment-oriented LCA method, the standard construction of PV modules and the principles of solar cells, an overview is given of the present and future material input for the above-mentioned PV-systems. Next, attention is paid to the energy consumption and the most important emissions of the production of the bulk materials. Based on these data three environmental effect scores of the PV systems are calculated and analyzed: the energy consumption, the greenhouse effect or global warming equivalent, and the acidifying effect or acidification equivalent. Also a fourth effect, for which the so-called environmental indicator human toxicity is defined, is described. By means of this indicator the hazardous effects for the public health can be indicated. The sum of the four indicators is a measure for the environmental profile of the roof PV-system and the ground PV-array system. Recommendations are given by which the systems and their environmental profiles can be improved. 29 figs., 50 tabs., 5 appendices, refs

  8. Interactions of efficiency and material requirements for terrestrial silicon solar cells

    Science.gov (United States)

    Bowler, D. L.; Wolf, M.

    1980-01-01

    The transport velocity transformation method was used to analyze solar cell designs to determine optimum cell structures. It was found that low resistivity materials should be used up to the onset of Auger recombination; a properly designed three-layer structure permits base region approaching an ideal device in performance; and that higher resistivity front regions will need more sophisticated grid metallization structures than those used now. It was concluded that new features will provide idealized silicon cell structures yielding airmass 1 efficiencies in the 24-26.5% range, with real efficiencies near 22%.

  9. Engineering spinal fusion: evaluating ceramic materials for cell based tissue engineered approaches

    NARCIS (Netherlands)

    Wilson, C.E.

    2011-01-01

    The principal aim of this thesis was to advance the development of tissue engineered posterolateral spinal fusion by investigating the potential of calcium phosphate ceramic materials to support cell based tissue engineered bone formation. This was accomplished by developing several novel model syst

  10. All solution processed tandem polymer solar cells based on thermocleavable materials

    DEFF Research Database (Denmark)

    Hagemann, Ole; Bjerring, Morten; Nielsen, Niels Chr.;

    2008-01-01

    Multilayer tandem polymer solar cells were prepared by solution processing using thermocleavable polymer materials that allow for conversion to an insoluble state through a short thermal treatment. The problems associated with solubility during application of subsequent layers in the stack were...

  11. 3D-Printing Crystallographic Unit Cells for Learning Materials Science and Engineering

    Science.gov (United States)

    Rodenbough, Philip P.; Vanti, William B.; Chan, Siu-Wai

    2015-01-01

    Introductory materials science and engineering courses universally include the study of crystal structure and unit cells, which are by their nature highly visual 3D concepts. Traditionally, such topics are explored with 2D drawings or perhaps a limited set of difficult-to-construct 3D models. The rise of 3D printing, coupled with the wealth of…

  12. Multi-Material Front Contact for 19% Thin Film Solar Cells

    Directory of Open Access Journals (Sweden)

    Joop van Deelen

    2016-02-01

    Full Text Available The trade-off between transmittance and conductivity of the front contact material poses a bottleneck for thin film solar panels. Normally, the front contact material is a metal oxide and the optimal cell configuration and panel efficiency were determined for various band gap materials, representing Cu(In,GaSe2 (CIGS, CdTe and high band gap perovskites. Supplementing the metal oxide with a metallic copper grid improves the performance of the front contact and aims to increase the efficiency. Various front contact designs with and without a metallic finger grid were calculated with a variation of the transparent conductive oxide (TCO sheet resistance, scribing area, cell length, and finger dimensions. In addition, the contact resistance and illumination power were also assessed and the optimal thin film solar panel design was determined. Adding a metallic finger grid on a TCO gives a higher solar cell efficiency and this also enables longer cell lengths. However, contact resistance between the metal and the TCO material can reduce the efficiency benefit somewhat.

  13. Ab initio Defect Energetics in LaBO3 Perovskite Solid Oxide Fuel Cell Materials

    DEFF Research Database (Denmark)

    Lee, Yueh-Lin; Morgan, Dane; Kleis, Jesper;

    2009-01-01

    Perovskite materials of the form ABO3 are a promising family of compounds for use in solid oxide fuel cell (SOFC) cathodes. Study of the physics of these compounds under SOFC conditions with ab initio methods is particularly challenging due to high temperatures, exchange of oxygen with O2 gas, and...

  14. Si solid-state quantum dot-based materials for tandem solar cells

    Science.gov (United States)

    Conibeer, Gavin; Perez-Wurfl, Ivan; Hao, Xiaojing; Di, Dawei; Lin, Dong

    2012-03-01

    The concept of third-generation photovoltaics is to significantly increase device efficiencies whilst still using thin-film processes and abundant non-toxic materials. A strong potential approach is to fabricate tandem cells using thin-film deposition that can optimise collection of energy in a series of cells with decreasing band gap stacked on top of each other. Quantum dot materials, in which Si quantum dots (QDs) are embedded in a dielectric matrix, offer the potential to tune the effective band gap, through quantum confinement, and allow fabrication of optimised tandem solar cell devices in one growth run in a thin-film process. Such cells can be fabricated by sputtering of thin layers of silicon rich oxide sandwiched between a stoichiometric oxide that on annealing crystallise to form Si QDs of uniform and controllable size. For approximately 2-nm diameter QDs, these result in an effective band gap of 1.8 eV. Introduction of phosphorous or boron during the growth of the multilayers results in doping and a rectifying junction, which demonstrates photovoltaic behaviour with an open circuit voltage ( V OC) of almost 500 mV. However, the doping behaviour of P and B in these QD materials is not well understood. A modified modulation doping model for the doping mechanisms in these materials is discussed which relies on doping of a sub-oxide region around the Si QDs.

  15. Mechanical characterisation of irradiated RPV materials by hot cell investigations to ensure RPV integrity

    International Nuclear Information System (INIS)

    The contribution gives an exemplary illustration of how to assess material characteristics after irradiation for the PWR power station GKN I and the BWR power station KKP1. This necessitates detailed mechanical technological investigations of test samples in so-called hot cells, which are evaluated according to current concepts according to KTA 3202. (orig.)

  16. Evaluating the potential of wine-making residues and corn cobs as support materials for cell immobilization for ethanol production

    OpenAIRE

    Genisheva, Zlatina Asenova; Mussatto, Solange I.; Oliveira, J. M.; Teixeira, J. A.

    2011-01-01

    Three wine-making residues(grape seeds, skins and stems), and corn cobs were evaluated as support material for immobilization of Saccharomyces cerevisiae and the ethanol production by the immobilized cells was assessed. The main objective of this study was to find an abundant and low cost material suitable for the cells immobilization and able to be used in a next step of wine production by immobilized yeast cells. The four natural materials were used as support in two different forms: untrea...

  17. Ultrathin Cu2O as an efficient inorganic hole transporting material for perovskite solar cells

    KAUST Repository

    Yu, Weili

    2016-02-18

    We demonstrate that ultrathin P-type Cu2O thin films fabricated by a facile thermal oxidation method can serve as a promising hole-transporting material in perovskite solar cells. Following a two-step method, inorganic-organic hybrid perovskite solar cells were fabricated and a power conversion efficiency of 11.0% was achieved. We find that the thickness and properties of Cu2O layers must be precisely tuned in order to achieve the optimal solar cell performance. The good performance of such perovskite solar cells can be attributed to the unique properties of ultrathin Cu2O, including high hole mobility, good energy level alignment with CH3NH3PbI3, and longer lifetime of photo-excited carriers. Combining merits of low cost, facile synthesis, and high device performance, ultrathin Cu2O films fabricated via thermal oxidation hold promise for facilitating the developments of industrial-scale perovskite solar cells.

  18. A Model for Compression-Weakening Materials and the Elastic Fields due to Contractile Cells

    CERN Document Server

    Rosakis, Phoebus; Ravichandran, Guruswami

    2014-01-01

    We construct a homogeneous, nonlinear elastic constitutive law, that models aspects of the mechanical behavior of inhomogeneous fibrin networks. Fibers in such networks buckle when in compression. We model this as a loss of stiffness in compression in the stress-strain relations of the homogeneous constitutive model. Problems that model a contracting biological cell in a finite matrix are solved. It is found that matrix displacements and stresses induced by cell contraction decay slower (with distance from the cell) in a compression weakening material, than linear elasticity would predict. This points toward a mechanism for long-range cell mechanosensing. In contrast, an expanding cell would induce displacements that decay faster than in a linear elastic matrix.

  19. Interaction of graphene-related materials with human intestinal cells: an in vitro approach

    Science.gov (United States)

    Kucki, M.; Rupper, P.; Sarrieu, C.; Melucci, M.; Treossi, E.; Schwarz, A.; León, V.; Kraegeloh, A.; Flahaut, E.; Vázquez, E.; Palermo, V.; Wick, P.

    2016-04-01

    Graphene-related materials (GRM) inherit unique combinations of physicochemical properties which offer a high potential for technological as well as biomedical applications. It is not clear which physicochemical properties are the most relevant factors influencing the behavior of GRM in complex biological environments. In this study we have focused on the interaction of GRM, especially graphene oxide (GO), and Caco-2 cells in vitro. We mimiked stomach transition by acid-treatment of two representative GRM followed by analysis of their physicochemical properties. No significant changes in the material properties or cell viability of exposed Caco-2 cells in respect to untreated GRM could be detected. Furthermore, we explored the interaction of four different GO and Caco-2 cells to identify relevant physicochemical properties for the establishment of a material property-biological response relationship. Despite close interaction with the cell surface and the formation of reactive oxygen species (ROS), no acute toxicity was found for any of the applied GO (concentration range 0-80 μg ml-1) after 24 h and 48 h exposure. Graphene nanoplatelet aggregates led to low acute toxicity at high concentrations, indicating that aggregation, the number of layers or the C/O ratio have a more pronounced effect on the cell viability than the lateral size alone.Graphene-related materials (GRM) inherit unique combinations of physicochemical properties which offer a high potential for technological as well as biomedical applications. It is not clear which physicochemical properties are the most relevant factors influencing the behavior of GRM in complex biological environments. In this study we have focused on the interaction of GRM, especially graphene oxide (GO), and Caco-2 cells in vitro. We mimiked stomach transition by acid-treatment of two representative GRM followed by analysis of their physicochemical properties. No significant changes in the material properties or cell

  20. Cytoprotective effects of graphene oxide for mammalian cells against internalization of exogenous materials

    Science.gov (United States)

    Na, Hee-Kyung; Kim, Mi-Hee; Lee, Jieon; Kim, Young-Kwan; Jang, Hongje; Lee, Kyung Eun; Park, Hyerim; Do Heo, Won; Jeon, Hyesung; Choi, Insung S.; Lee, Younghoon; Min, Dal-Hee

    2013-01-01

    To date, graphene oxide (GO), an oxidized version of graphene, has been utilized in many research areas including bioapplications such as drug delivery and bioanalysis. Unlike other spherical or polygonal nanomaterials, GO exhibits a sheet-like structure, which in itself suggests interesting applications based on its shape. Here we show that GO can protect cells from internalization of toxic hydrophobic molecules, nanoparticles, and nucleic acids such as siRNA and plasmid DNA by interacting with cell surface lipid bilayers without noticeably reducing cell viability. Furthermore, the cytoprotective effect of GO against the internalization of extracellular materials enabled spatial control over gene transfection through region-selective gene delivery only into GO-untreated cells, and not into the GO-treated cells.To date, graphene oxide (GO), an oxidized version of graphene, has been utilized in many research areas including bioapplications such as drug delivery and bioanalysis. Unlike other spherical or polygonal nanomaterials, GO exhibits a sheet-like structure, which in itself suggests interesting applications based on its shape. Here we show that GO can protect cells from internalization of toxic hydrophobic molecules, nanoparticles, and nucleic acids such as siRNA and plasmid DNA by interacting with cell surface lipid bilayers without noticeably reducing cell viability. Furthermore, the cytoprotective effect of GO against the internalization of extracellular materials enabled spatial control over gene transfection through region-selective gene delivery only into GO-untreated cells, and not into the GO-treated cells. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr33800a

  1. Perovskite Solar Cells: Influence of Hole Transporting Materials on Power Conversion Efficiency.

    Science.gov (United States)

    Ameen, Sadia; Rub, Malik Abdul; Kosa, Samia A; Alamry, Khalid A; Akhtar, M Shaheer; Shin, Hyung-Shik; Seo, Hyung-Kee; Asiri, Abdullah M; Nazeeruddin, Mohammad Khaja

    2016-01-01

    The recent advances in perovskite solar cells (PSCs) created a tsunami effect in the photovoltaic community. PSCs are newfangled high-performance photovoltaic devices with low cost that are solution processable for large-scale energy production. The power conversion efficiency (PCE) of such devices experienced an unprecedented increase from 3.8 % to a certified value exceeding 20 %, demonstrating exceptional properties of perovskites as solar cell materials. A key advancement in perovskite solar cells, compared with dye-sensitized solar cells, occurred with the replacement of liquid electrolytes with solid-state hole-transporting materials (HTMs) such as 2,2',7,7'-tetrakis-(N,N-di-4-methoxyphenylamino)-9,9'-spirobifluorene (Spiro-OMeTAD), which contributed to enhanced PCE values and improved the cell stability. Following improvements in the perovskite crystallinity to produce a smooth, uniform morphology, the selective and efficient extraction of positive and negative charges in the device dictated the PCE of PSCs. In this Review, we focus mainly on the HTMs responsible for hole transport and extraction in PSCs, which is one of the essential components for efficient devices. Here, we describe the current state-of-the-art in molecular engineering of hole-transporting materials that are used in PSCs and highlight the requisites for market-viability of this technology. Finally, we include an outlook on molecular engineering of new functional HTMs for high efficiency PSCs. PMID:26692567

  2. Materials and design development for bipolar/end plates in fuel cells

    Science.gov (United States)

    Kumar, Atul; Reddy, Ramana G.

    Bipolar/end plate is one of the most important and costliest components of the fuel cell stack and accounts to more than 80% of the total weight of the stack. In the present work, we focus on the development of alternative materials and design concepts for these plates. A prototype one-cell polymer electrolyte membrane (PEM) fuel cell stack made out of SS-316 bipolar/end plate was fabricated and assembled. The use of porous material in the gas flow-field of bipolar/end plates was proposed, and the performance of these was compared to the conventional channel type of design. Three different porous materials were investigated, viz. Ni-Cr metal foam (50 PPI), SS-316 metal foam (20 PPI), and the carbon cloth. It was seen that the performance of fuel cell with Ni-Cr metal foam was highest, and decreased in the order SS-316 metal foam, conventional multi-parallel flow-field channel design and carbon cloth. This trend was explained based on the effective permeability of the gas flow-field in the bipolar/end plates. The use of metal foams with low permeability values resulted in an increased pressure drop across the flow-field which enhanced the cell performance.

  3. One-Step Facile Synthesis of a Simple Hole Transport Material for Efficient Perovskite Solar Cells

    KAUST Repository

    Chen, Hu

    2016-04-04

    A hole transporting material was designed for use in perovskite solar cells, with a facile one-step synthesis from inexpensive, com-mercially available reagents. The molecule comprises a central fluorinated phenyl core with pendant aryl amines, namely, 3,6-difluoro-N1,N1,N2,N2,N4,N4,N5,N5-octakis(4-methoxyphenyl)benzene-1,2,4,5-tetraamine (DFTAB). A power conversion efficiency of up to 10.4% was achieved in a mesoporous perovskite device architecture. The merits of a simple and potentially low cost syn-thetic route as well as promising performance in perovskite devices, encourages further development of this materials class as new low-cost hole transporting materials for the scale up of perovskite solar cells.

  4. Electrodeposited copper front metallization for silicon heterojunction solar cells: materials and processes

    Energy Technology Data Exchange (ETDEWEB)

    Geissbühler, J.; Martin de Nicolas, S.; Faes, A.; Lachowicz, A.; Tomasi, A.; Paviet-Salomon, B.; Lachenal, D.; Papet, P.; Badel, N.; Barraud, L.; Descoeudres, A.; Despeisse, M.; De Wolf, S.; Ballif, C.

    2014-10-20

    Even though screen-printing of low-temperature silver paste remains the state-of-the-art technique for the front-metallization of SHJ solar cells, recent studies have demonstrated large efficiency improvements when copper-electroplated contacts are used instead of screen-printed ones. However, due to the new materials and the new processes introduced by this technique, it is crucial to individually investigate their compatibility with the SHJ cell structure. In this study, we present a detailed analysis of how the performances of SHJ devices may be modified by these new materials and processes. First, effects on the amorphous silicon (a-Si:H) passivation have been studied for various processes such as DI water rinsing, dips in a copper removal solution and direct evaporation of copper on the a-Si:H. Finally, copper electroplating technique has been adapted in order to be applied to more complex cell structures such as high-efficiency IBC-SHJ.

  5. Transition from Bioinert to Bioactive Material by Tailoring the Biological Cell Response to Carboxylated Nanocellulose.

    Science.gov (United States)

    Hua, Kai; Rocha, Igor; Zhang, Peng; Gustafsson, Simon; Ning, Yi; Strømme, Maria; Mihranyan, Albert; Ferraz, Natalia

    2016-03-14

    This work presents an insight into the relationship between cell response and physicochemical properties of Cladophora cellulose (CC) by investigating the effect of CC functional group density on the response of model cell lines. CC was carboxylated by electrochemical TEMPO-mediated oxidation. By varying the amount of charge passed through the electrolysis setup, CC materials with different degrees of oxidation were obtained. The effect of carboxyl group density on the material's physicochemical properties was investigated together with the response of human dermal fibroblasts (hDF) and human osteoblastic cells (Saos-2) to the carboxylated CC films. The introduction of carboxyl groups resulted in CC films with decreased specific surface area and smaller total pore volume compared with the unmodified CC (u-CC). While u-CC films presented a porous network of randomly oriented fibers, a compact and aligned fiber pattern was depicted for the carboxylated-CC films. The decrease in surface area and total pore volume, and the orientation and aggregation of the fibers tended to augment parallel to the increase in the carboxyl group density. hDF and Saos-2 cells presented poor cell adhesion and spreading on u-CC, which gradually increased for the carboxylated CC as the degree of oxidation increased. It was found that a threshold value in carboxyl group density needs be reached to obtain a carboxylated-CC film with cytocompatibility comparable to commercial tissue culture material. Hence, this study demonstrates that a normally bioinert nanomaterial can be rendered bioactive by carefully tuning the density of charged groups on the material surface, a finding that not only may contribute to the fundamental understanding of biointerface phenomena, but also to the development of bioinert/bioactive materials. PMID:26886265

  6. Imidazolium-Based Polymeric Materials as Alkaline Anion-Exchange Fuel Cell Membranes

    Science.gov (United States)

    Narayan, Sri R.; Yen, Shiao-Ping S.; Reddy, Prakash V.; Nair, Nanditha

    2012-01-01

    Polymer electrolyte membranes that conduct hydroxide ions have potential use in fuel cells. A variety of polystyrene-based quaternary ammonium hydroxides have been reported as anion exchange fuel cell membranes. However, the hydrolytic stability and conductivity of the commercially available membranes are not adequate to meet the requirements of fuel cell applications. When compared with commercially available membranes, polystyrene-imidazolium alkaline membrane electrolytes are more stable and more highly conducting. At the time of this reporting, this has been the first such usage for imidazolium-based polymeric materials for fuel cells. Imidazolium salts are known to be electrochemically stable over wide potential ranges. By controlling the relative ratio of imidazolium groups in polystyrene-imidazolium salts, their physiochemical properties could be modulated. Alkaline anion exchange membranes based on polystyrene-imidazolium hydroxide materials have been developed. The first step was to synthesize the poly(styrene-co-(1-((4-vinyl)methyl)-3- methylimidazolium) chloride through a free-radical polymerization. Casting of this material followed by in situ treatment of the membranes with sodium hydroxide solutions provided the corresponding hydroxide salts. Various ratios of the monomers 4-chloromoethylvinylbenzine (CMVB) and vinylbenzine (VB) provided various compositions of the polymer. The preferred material, due to the relative ease of casting the film, and its relatively low hygroscopic nature, was a 2:1 ratio of CMVB to VB. Testing confirmed that at room temperature, the new membranes outperformed commercially available membranes by a large margin. With fuel cells now in use at NASA and in transportation, and with defense potential, any improvement to fuel cell efficiency is a significant development.

  7. U.S. Department of Energy-Funded Performance Validation of Fuel Cell Material Handling Equipment (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Kurtz, J.; Sprik, S.; Ramsden, T.; Saur, G.; Ainscough, C.; Post, M.; Peters, M.

    2013-11-01

    This webinar presentation to the UK Hydrogen and Fuel Cell Association summarizes how the U.S. Department of Energy is enabling early fuel cell markets; describes objectives of the National Fuel Cell Technology Evaluation Center; and presents performance status of fuel cell material handling equipment.

  8. Evaluation of the Total Cost of Ownership of Fuel Cell-Powered Material Handling Equipment

    Energy Technology Data Exchange (ETDEWEB)

    Ramsden, T.

    2013-04-01

    This report discusses an analysis of the total cost of ownership of fuel cell-powered and traditional battery-powered material handling equipment (MHE, or more typically 'forklifts'). A number of fuel cell MHE deployments have received funding support from the federal government. Using data from these government co-funded deployments, DOE's National Renewable Energy Laboratory (NREL) has been evaluating the performance of fuel cells in material handling applications. NREL has assessed the total cost of ownership of fuel cell MHE and compared it to the cost of ownership of traditional battery-powered MHE. As part of its cost of ownership assessment, NREL looked at a range of costs associated with MHE operation, including the capital costs of battery and fuel cell systems, the cost of supporting infrastructure, maintenance costs, warehouse space costs, and labor costs. Considering all these costs, NREL found that fuel cell MHE can have a lower overall cost of ownership than comparable battery-powered MHE.

  9. Comparison of silicon oxide and silicon carbide absorber materials in silicon thin-film solar cells

    Directory of Open Access Journals (Sweden)

    Walder Cordula

    2015-01-01

    Full Text Available Since solar energy conversion by photovoltaics is most efficient for photon energies at the bandgap of the absorbing material the idea of combining absorber layers with different bandgaps in a multijunction cell has become popular. In silicon thin-film photovoltaics a multijunction stack with more than two subcells requires a high bandgap amorphous silicon alloy top cell absorber to achieve an optimal bandgap combination. We address the question whether amorphous silicon carbide (a-SiC:H or amorphous silicon oxide (a-SiO:H is more suited for this type of top cell absorber. Our single cell results show a better performance of amorphous silicon carbide with respect to fill factor and especially open circuit voltage at equivalent Tauc bandgaps. The microstructure factor of single layers indicates less void structure in amorphous silicon carbide than in amorphous silicon oxide. Yet photoconductivity of silicon oxide films seems to be higher which could be explained by the material being not truly intrinsic. On the other hand better cell performance of amorphous silicon carbide absorber layers might be connected to better hole transport in the cell.

  10. Comparison of silicon oxide and silicon carbide absorber materials in silicon thin-film solar cells

    Science.gov (United States)

    Walder, Cordula; Kellermann, Martin; Wendler, Elke; Rensberg, Jura; von Maydell, Karsten; Agert, Carsten

    2015-02-01

    Since solar energy conversion by photovoltaics is most efficient for photon energies at the bandgap of the absorbing material the idea of combining absorber layers with different bandgaps in a multijunction cell has become popular. In silicon thin-film photovoltaics a multijunction stack with more than two subcells requires a high bandgap amorphous silicon alloy top cell absorber to achieve an optimal bandgap combination. We address the question whether amorphous silicon carbide (a-SiC:H) or amorphous silicon oxide (a-SiO:H) is more suited for this type of top cell absorber. Our single cell results show a better performance of amorphous silicon carbide with respect to fill factor and especially open circuit voltage at equivalent Tauc bandgaps. The microstructure factor of single layers indicates less void structure in amorphous silicon carbide than in amorphous silicon oxide. Yet photoconductivity of silicon oxide films seems to be higher which could be explained by the material being not truly intrinsic. On the other hand better cell performance of amorphous silicon carbide absorber layers might be connected to better hole transport in the cell.

  11. Thermocleavable materials for polymer solar cells with high open circuit voltage-a comparative study.

    Science.gov (United States)

    Tromholt, Thomas; Gevorgyan, Suren A; Jørgensen, Mikkel; Krebs, Frederik C; Sylvester-Hvid, Kristian O

    2009-12-01

    The search for polymer solar cells giving a high open circuit voltage was conducted through a comparative study of four types of bulk-heterojunction solar cells employing different photoactive layers. As electron donors the thermo-cleavable polymer poly-(3-(2-methylhexyloxycarbonyl)dithiophene) (P3MHOCT) and unsubstituted polythiophene (PT) were used, the latter of which results from thermo cleaving the former at 310 degrees C. As reference, P3HT solar cells were built in parallel. As electron acceptors, either PCBM or bis-[60]PCBM were used. In excess of 300 solar cells were produced under as identical conditions as possible, varying only the material combination of the photo active layer. It was observed that on replacing PCBM with bis[60]PCBM, the open circuit voltage on average increased by 100 mV for P3MHOCT and 200 mV for PT solar cells. Open circuit voltages approaching 1 V were observed for the PT:bis[60]PCBM solar cells and a maximum conversion efficiency of 1.3% was obtained for solar cells with P3MHOCT:PCBM as the photoactive material. For the reference solar cells maximum efficiencies of 2.1 and 2.4% were achieved for P3HT:PCBM and P3HT:bis[60]PCBM, respectively. Despite special measures taken in terms of substrate design and device processing, a substantial spread in the photovoltaic properties was generally observed. This spread could not be correlated with the optical properties of the solar cells, the thickness of the photo active layer or the electrode deposition conditions of the aluminum top electrode. PMID:20356155

  12. Hetero-cellular prototyping by synchronized multi-material bioprinting for rotary cell culture system.

    Science.gov (United States)

    Snyder, Jessica; Son, Ae Rin; Hamid, Qudus; Wu, Honglu; Sun, Wei

    2016-03-01

    Bottom-up tissue engineering requires methodological progress of biofabrication to capture key design facets of anatomical arrangements across micro, meso and macro-scales. The diffusive mass transfer properties necessary to elicit stability and functionality require hetero-typic contact, cell-to-cell signaling and uniform nutrient diffusion. Bioprinting techniques successfully build mathematically defined porous architecture to diminish resistance to mass transfer. Current limitations of bioprinted cell assemblies include poor micro-scale formability of cell-laden soft gels and asymmetrical macro-scale diffusion through 3D volumes. The objective of this work is to engineer a synchronized multi-material bioprinter (SMMB) system which improves the resolution and expands the capability of existing bioprinting systems by packaging multiple cell types in heterotypic arrays prior to deposition. This unit cell approach to arranging multiple cell-laden solutions is integrated with a motion system to print heterogeneous filaments as tissue engineered scaffolds and nanoliter droplets. The set of SMMB process parameters control the geometric arrangement of the combined flow's internal features and constituent material's volume fractions. SMMB printed hepatocyte-endothelial laden 200 nl droplets are cultured in a rotary cell culture system (RCCS) to study the effect of microgravity on an in vitro model of the human hepatic lobule. RCCS conditioning for 48 h increased hepatocyte cytoplasm diameter 2 μm, increased metabolic rate, and decreased drug half-life. SMMB hetero-cellular models present a 10-fold increase in metabolic rate, compared to SMMB mono-culture models. Improved bioprinting resolution due to process control of cell-laden matrix packaging as well as nanoliter droplet printing capability identify SMMB as a viable technique to improve in vitro model efficacy. PMID:26759993

  13. Material Selection for Dye Sensitized Solar Cells Using Multiple Attribute Decision Making Approach

    Directory of Open Access Journals (Sweden)

    Sarita Baghel

    2014-01-01

    Full Text Available Dye sensitized solar cells (DSCs provide a potential alternative to conventional p-n junction photovoltaic devices. The semiconductor thin film plays a crucial role in the working of DSC. This paper aims at formulating a process for the selection of optimum semiconductor material for nanostructured thin film using multiple attribute decision making (MADM approach. Various possible available semiconducting materials and their properties like band gap, cost, mobility, rate of electron injection, and static dielectric constant are considered and MADM technique is applied to select the best suited material. It was found that, out of all possible candidates, titanium dioxide (TiO2 is the best semiconductor material for application in DSC. It was observed that the proposed results are in good agreement with the experimental findings.

  14. Enhancing solar cell efficiency: the search for luminescent materials as spectral converters.

    Science.gov (United States)

    Huang, Xiaoyong; Han, Sanyang; Huang, Wei; Liu, Xiaogang

    2013-01-01

    Photovoltaic (PV) technologies for solar energy conversion represent promising routes to green and renewable energy generation. Despite relevant PV technologies being available for more than half a century, the production of solar energy remains costly, largely owing to low power conversion efficiencies of solar cells. The main difficulty in improving the efficiency of PV energy conversion lies in the spectral mismatch between the energy distribution of photons in the incident solar spectrum and the bandgap of a semiconductor material. In recent years, luminescent materials, which are capable of converting a broad spectrum of light into photons of a particular wavelength, have been synthesized and used to minimize the losses in the solar-cell-based energy conversion process. In this review, we will survey recent progress in the development of spectral converters, with a particular emphasis on lanthanide-based upconversion, quantum-cutting and down-shifting materials, for PV applications. In addition, we will also present technical challenges that arise in developing cost-effective high-performance solar cells based on these luminescent materials. PMID:23072924

  15. New electron beam facility for irradiated plasma facing materials testing in hot cell

    Energy Technology Data Exchange (ETDEWEB)

    Sakamoto, N.; Kawamura, H. [Oarai Research Establishment, Ibaraki-ken (Japan); Akiba, M. [Naka Research Establishment, Ibaraki-ken (Japan)

    1995-09-01

    Since plasma facing components such as the first wall and the divertor for the next step fusion reactors are exposed to high heat loads and high energy neutron flux generated by the plasma, it is urgent to develop of plasma facing components which can resist these. Then, we have established electron beam heat facility ({open_quotes}OHBIS{close_quotes}, Oarai Hot-cell electron Beam Irradiating System) at a hot cell in JMTR (Japan Materials Testing Reactor) hot laboratory in order to estimate thermal shock resistivity of plasma facing materials and heat removal capabilities of divertor elements under steady state heating. In this facility, irradiated plasma facing materials (beryllium, carbon based materials and so on) and divertor elements can be treated. This facility consists of an electron beam unit with the maximum beam power of 50kW and the vacuum vessel. The acceleration voltage and the maximum beam current are 30kV (constant) and 1.7A, respectively. The loading time of electron beam is more than 0.1ms. The shape of vacuum vessel is cylindrical, and the mainly dimensions are 500mm in inner diameter, 1000mm in height. The ultimate vacuum of this vessel is 1 x 10{sup -4}Pa. At present, the facility for thermal shock test has been established in a hot cell. And performance estimation on the electron beam is being conducted. Presently, the devices for heat loading tests under steady state will be added to this facility.

  16. WaterTransport in PEM Fuel Cells: Advanced Modeling, Material Selection, Testing and Design Optimization

    Energy Technology Data Exchange (ETDEWEB)

    J. Vernon Cole; Abhra Roy; Ashok Damle; Hari Dahr; Sanjiv Kumar; Kunal Jain; Ned Djilai

    2012-10-02

    Water management in Proton Exchange Membrane, PEM, Fuel Cells is challenging because of the inherent conflicts between the requirements for efficient low and high power operation. Particularly at low powers, adequate water must be supplied to sufficiently humidify the membrane or protons will not move through it adequately and resistance losses will decrease the cell efficiency. At high power density operation, more water is produced at the cathode than is necessary for membrane hydration. This excess water must be removed effectively or it will accumulate in the Gas Diffusion Layers, GDLs, between the gas channels and catalysts, blocking diffusion paths for reactants to reach the catalysts and potentially flooding the electrode. As power density of the cells is increased, the challenges arising from water management are expected to become more difficult to overcome simply due to the increased rate of liquid water generation relative to fuel cell volume. Thus, effectively addressing water management based issues is a key challenge in successful application of PEMFC systems. In this project, CFDRC and our partners used a combination of experimental characterization, controlled experimental studies of important processes governing how water moves through the fuel cell materials, and detailed models and simulations to improve understanding of water management in operating hydrogen PEM fuel cells. The characterization studies provided key data that is used as inputs to all state-of-the-art models for commercially important GDL materials. Experimental studies and microscopic scale models of how water moves through the GDLs showed that the water follows preferential paths, not branching like a river, as it moves toward the surface of the material. Experimental studies and detailed models of water and airflow in fuel cells channels demonstrated that such models can be used as an effective design tool to reduce operating pressure drop in the channels and the associated

  17. Deposition pressure effects on material structure and performance of micromorph tandem solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Delli Veneri, Paola; Mercaldo, Lucia V.; Privato, Carlo [Enea, Portici Research Center, Localita Granatello, 80055 Portici, Napoli (Italy)

    2008-01-15

    Tandem solar cells represent an elegant way of overcoming the efficiency limits of single-junction solar cells and reducing the light-induced degradation of amorphous silicon films. Stacked structures consisting of an amorphous silicon top cell and a microcrystalline silicon bottom cell allow a good utilization of the solar spectrum due to the band gap values of the two materials. These devices, firstly introduced by the IMT research group, were designated as ''micromorph'' tandem solar cells. To better exploit this concept, it is important to tune parameters like the band gaps and the short-circuit currents. In this work, we have realized micromorph tandem solar cells on Asahi U-type TCO-covered glass substrates. The intrinsic layer of both the amorphous top cell and the microcrystalline bottom cell is grown by very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD) at 100 MHz at low substrate temperature (150{sup o}C). Finally, a ZnO reflector and a metal contact complete the structure. No intermediate optical mirror between the two cells is used at this stage. Undiluted a-Si:H, with reduced band gap when compared to H{sub 2}-diluted amorphous silicon, is used as absorber layer in the top cell. As for the bottom cell, the high-pressure-high-power regime (up to 267 Pa-80 W) has been explored aiming at growing high-quality microcrystalline silicon at large deposition rates. The effect of the structural composition of the microcrystalline absorber layer on the current-voltage characteristic and spectral response of tandem devices has been investigated. An efficiency of 11.3% has been obtained with short-circuit current densities around 13 mA/cm{sup 2}, open-circuit voltages {proportional_to}1.34 V and fill factors {proportional_to}66%. (author)

  18. Different materials as a cathode modification layer on the impact of organic solar cells

    Science.gov (United States)

    Zhong, Jian; Huang, Qiuyan; Yu, Junsheng; Jiang, Yadong

    2010-10-01

    Organic thin film solar cells based on conjugated polymer or small molecules have showed an interesting approach to energy conversion since Tang reported a single donor-accepter hetero-junction solar cell. The power conversion efficiency of organic solar cells has increased steadily over last decade. Small-molecular weight organic double heterojunction donor-acceptor layer organic solar cells (OSC) with a structure of indium-tin-oxide (ITO)/CuPc(200Å)/C60(400Å)/x/Ag(1000Å), using CuPc(copper Phthalocyanine)as donor layer, and Alq3(8-Hydroxyquinoline aluminum salt), BCP(Bromocresol purple sodium salt) and Bphen(4'7-diphyenyl-1,10-phenanthroline) as cathode modification layer, respectively were fabricated. The performance of OSC was studied as a function of the different materials as an cathode modification layer to optimize the structure. The current-voltage characteristic of the solar cell under AM1.5 solar illumination at an intensity of 100 mw/cm2 showed that the power conversion efficiency (PCE) was dependent of the different materials of the cathode modification layer. the efficiency along with the different materials as an cathode modification layer will diminish under that standard solar illumination(AM1.5)was obtained. Using a double heterostructure of ITO/CuPc(200Å)/C60(400Å)/Alq3(60Å)/Ag(1000Å) with high-vacuum evaporation technology, the efficiency was 0.587%.the efficiency was 0.967% when the material of the cathode modification layer was BCP, with the structure of ITO/CuPc(200Å)/C60(400Å)/BCP(35Å)/Ag(1000Å), and the efficiency was 0.742% when the material of the cathode modification layer was Bphen, with the structure of ITO/CuPc(200Å)/C60(400Å)/ Bphen(50Å)/Ag(1000Å).Using different materials as a cathode modification layer, it can be seen that the material which matches the energy level could even eventually be able to improve the energy conversion efficiency more.

  19. Hot cell works and related irradiation tests in fission reactor for development of new materials for nuclear application

    International Nuclear Information System (INIS)

    Present status of research works in Oarai Branch, Institute for Materials Research, Tohoku University, utilizing Japan Materials Testing Reactor and related hot cells will be described.Topics are mainly related with nuclear materials studies, excluding fissile materials, which is mainly aiming for development of materials for advanced nuclear systems such as a nuclear fusion reactor. Conflict between traditional and routined procedures and new demands will be described and future perspective is discussed. (author)

  20. Theoretical modelling of intermediate band solar cell materials based on metal-doped chalcopyrite compounds

    International Nuclear Information System (INIS)

    Electronic structure calculations are carried out for CuGaS2 partially substituted with Ti, V, Cr or Mn to ascertain if some of these systems could provide an intermediate band material able to give a high efficiency photovoltaic cell. Trends in electronic level positions are analyzed and more accurate advanced theory levels (exact exchange or Hubbard-type methods) are used in some cases. The Ti-substituted system seems more likely to yield an intermediate band material with the desired properties, and furthermore seems realizable from the thermodynamic point of view, while those with Cr and Mn might give half-metal structures with applications in spintronics

  1. Organic-inorganic hybrid perovskites as light absorbing/hole conducting material in solar cells

    OpenAIRE

    Ghanavi, Saman

    2013-01-01

    Solar cells involving two different perovskites were manufactured and analyzed. The perovskites were (CH3NH3)PbI3 and (CH3NH3)SnI3. Both perovskites have a shared methyl ammonium group (MA) and are used as both light absorbing material and hole conducting material (HTM) in this project. The preparation procedures for the complete device were according to previous attempts to make stable organic-inorganic hybrid perovskites and involved different layers and procedures. Both perovskites were ma...

  2. Solution-processed cathode interfacial layer materials for high-efficiency polymer solar cells

    Directory of Open Access Journals (Sweden)

    Biao Xiao

    2015-09-01

    Full Text Available Polymer solar cells (PSCs are a new type of renewable energy source currently being extensively investigated due to perceived advantages; such as being lightweight, low-cost and because of the unlimited materials resource. The power conversion efficiency of state-of-the-art PSCs has increased dramatically in the past few years, obtained mainly through the development of new electron donor polymers, acceptors, and novel device structures through the use of various electrode interfacial materials. In this short review, recent progress in solution-processed cathode interfacial layers that could significantly improve device performances is summarized and highlighted.

  3. Theoretical modelling of intermediate band solar cell materials based on metal-doped chalcopyrite compounds

    Energy Technology Data Exchange (ETDEWEB)

    Palacios, P. [Instituto de Energia Solar and Dpt. de Tecnologias Especiales, ETSI de Telecomunicacion, UPM, Ciudad Universitaria s/n, 28040 Madrid (Spain)]. E-mail: pablop@etsit.upm.es; Sanchez, K. [Instituto de Energia Solar and Dpt. de Tecnologias Especiales, ETSI de Telecomunicacion, UPM, Ciudad Universitaria s/n, 28040 Madrid (Spain); Conesa, J.C. [Instituto de Catalisis y Petroleoquimica, CSIC, Marie Curie 2, Cantoblanco, 28049 Madrid (Spain); Fernandez, J.J. [Dpt. de Fisica Fundamental, Universidad Nacional de Educacion a Distancia, 28080, Madrid (Spain); Wahnon, P. [Instituto de Energia Solar and Dpt. de Tecnologias Especiales, ETSI de Telecomunicacion, UPM, Ciudad Universitaria s/n, 28040 Madrid (Spain)

    2007-05-31

    Electronic structure calculations are carried out for CuGaS{sub 2} partially substituted with Ti, V, Cr or Mn to ascertain if some of these systems could provide an intermediate band material able to give a high efficiency photovoltaic cell. Trends in electronic level positions are analyzed and more accurate advanced theory levels (exact exchange or Hubbard-type methods) are used in some cases. The Ti-substituted system seems more likely to yield an intermediate band material with the desired properties, and furthermore seems realizable from the thermodynamic point of view, while those with Cr and Mn might give half-metal structures with applications in spintronics.

  4. Material characterizations and devices tests of solar cells based on III-V elements nitrides

    OpenAIRE

    Gorge, Vanessa

    2012-01-01

    Among III-V nitrides, the InGaN material has intensively been studied since the year 2000 for photovoltaic applications, in particular for multi-junction solar cells, thanks to its large tunable band gap covering almost the entire solar spectrum. Then, it will be possible to reach high efficiency and low cost. However, one of the problems of InGaN material is the absence of lattice-matched substrate leading to high defect density which limits device performances. We have thus studied the feas...

  5. Material characterization of open-cell foams by finite element based micromechanics methods

    Science.gov (United States)

    Thiyagasundaram, Prasanna

    Finite element based micromechanics methods have been used for predicting elastic properties, failure strengths, mode-I, mode-II and mixed mode fracture toughness of open-cell foams. In predicting the orthotropic elastic properties, foams with both equisided and Kelvin-elongated tetrakaidecahedron unit cells are studied. Periodic Boundary Conditions (PBCs) exploiting the special repeating microstructural geometry for these materials have been derived and have been applied on the micromechanical model to calculate the elastic properties. It is shown that the results for the elastic constants from these finite element based models agree well with the available analytical models. Further studies such as effect of a varying strut cross-section over a uniform strut cross-section on the elastic properties are also done in the same context. Next, the procedures used for predicting the above elastic properties are extended to predict multi-axial failure strengths of these low density open cell foams with a microstructure made out of tetrakaidecahedral unit cells. Again, foams with both equisided tetrakaidecahedron and Kelvin-elongated tetrakaidecahedron as unit cells are studied. Failure strengths in different material directions are computed using direct Micromechanics based Methods (DMM). Further, the effect of a varying strut cross section over a uniform strut cross section on failure strengths is also presented. Bi-axial failure envelopes for foams with equisided tetrakaidecahedron unit cells are shown to take the shape of a regular hexagon in the hydrostatic plane. The tri-axial failure envelope for foams made out of equisided tetrakaidecahedron unit cells is shown to have a shape of a double hexagonal pyramid. The bi-axial and tri-axial failure envelopes of foams with elongated tetrakaidecahedron unit cells are also plotted and the effect of anisotropy in foams with these unit cells on the failure envelopes is also discussed. Next, global-local models are developed

  6. Analysis of CdTe solar cells in relation to materials issues

    International Nuclear Information System (INIS)

    By now, extensive experimental research is available on thin film solar cells based on CdTe and on CIGS, and their electrical and optical behaviour is characterised by a multitude of diverse characterisation techniques. At the same time, numerical simulation programmes have matured and are available to the research community to assist in interpreting these measurements consistently. Once multiple measurements are (more or less) quantitatively described, the numerical simulation can be used to explore the effect of a variation of materials parameter (e.g. the presence or absence of a property, or variation in a range of values) to the final solar cell characteristics. Examples of such analysis for CdTe solar cells are shown. In CdTe cells, much research has been devoted to the activation treatment of the absorber, and to the technology of the back contact. Analysis of ample measurements has evidenced the crucial role of the profile of the (effective) doping density through the device. It will be illustrated how this relative simple (but hardly mastered) materials property has a far reaching influence to the cell characteristics such as roll-over and cross-over of I-V curves, also in dependence on illumination and voltage, conventional and apparent quantum efficiency, and finally fill factor and efficiency

  7. Wired enzymes in mesoporous materials: A benchmark for fabricating biofuel cells.

    Science.gov (United States)

    Catalano, Paolo N; Wolosiuk, Alejandro; Soler-Illia, Galo J A A; Bellino, Martín G

    2015-12-01

    Evolution of fuel cells using metallic inorganic catalysts has led to the development of biofuel cells with potential applications in implantable devices. However, the main disadvantages in real world applications of enzymatic biofuel cells are short lifetime and low power density. Many efforts have been devoted to immobilize redox enzymes on surfaces to allow efficient electrical communication with electrodes and to provide an adequate habitat for biochemical activity. In this context, nanocavities of mesoporous materials offer a tailored environment for protein immobilization. Mesostructured platforms with high surface area and stability have been developed to enhance mass transport, charge transfer from biocatalysts to electrodes and enzyme stability, leading to biofuel cells with improved power density (up to 602 μW cm(-2) at physiological conditions) and overall performance (high stability after 30 h of continuous operation and after 10 days of storage). This review discusses recent developments using mesoporous materials as novel platforms for effective electronic charge transfer in the context of current and emerging technologies in enzymatic fuel cell research, emphasizing their practical implications and potential improvements leading to a major impact on medical science and portable electronics. PMID:26187442

  8. Differentiated growth of human renal tubule cells on thin-film and nanostructured materials.

    Science.gov (United States)

    Fissell, William H; Manley, Sargum; Westover, Angela; Humes, H David; Fleischman, Aaron J; Roy, Shuvo

    2006-01-01

    Over 300,000 Americans are dependent on hemodialysis as treatment for renal failure, and kidney transplantation is limited by scarcity of donor organs. This shortage has prompted research into tissue engineering of renal replacement therapy. Existing bioartificial kidneys are large and their use labor intensive, but they have shown improved survival compared to conventional therapy in preclinical studies and an US Food and Drug Administration-approved phase 2 clinical trial. This hybrid technology will require miniaturization of hemofilters, cell culture substrates, sensors, and integration of control electronics. Using the same harvesting and isolation techniques used in preparing bioartificial kidneys for clinical use, we characterized human renal tubule cell growth on a variety of silicon and related thin-film material substrates commonly used in the construction of microelectromechanical systems (MEMS), as well as novel silicon nanopore membranes (SNMs). Human cortical tubular epithelial cells (HCTC) were seeded onto samples of single-crystal silicon, polycrystalline silicon, silicon dioxide, silicon nitride, SU-8 photoresist, SNMs, and polyester tissue culture inserts, and grown to confluence. The cells formed confluent monolayers with tight junctions and central cilia. Transepithelial resistances were similar between SNMs and polyester membranes. The differentiated growth of human tubular epithelial cells on MEMS materials strongly suggests that miniaturization of the existing bioartificial kidney will be feasible, paving the way for widespread application of this novel technology. PMID:16760708

  9. Review of bipolar plates in PEM fuel cells: flow field designs, materials and manufacturing techniques

    International Nuclear Information System (INIS)

    The polymer electrolyte membrane (PEM) fuel cell is a promising candidate as zero-emission power source for transport and stationary cogeneration applications due to its high efficiency, low temperature operation, high power density, fast start-up, and system robustness. Bipolar plate is a vital component of PEM fuel cells, which supplies fuel and oxidant to reactive sites, removes reaction products, collects produced current and provides mechanical support for the cells in the stack. Bipolar plates constitute more than 60% of the weight and 30% of the total cost in a fuel cell stack. For this reason, the weight, volume and cost of the fuel cell stack can be reduced significantly by improving layout configuration of flow field and use of light weight materials. Different combinations of materials, flow field layouts and fabrication techniques have been developed for these plates to achieve aforementioned functions efficiently, with the aim of obtaining high performance and economic advantages. The present paper presents a comprehensive review of these combinations and their pros and cons. (author)

  10. APPLICATION OF DOPANT-FREE HOLE TRANSPORT MATERIALS FOR PEROVSKITE SOLAR CELLS

    OpenAIRE

    Franckevičius, Marius; Mishra, Amaresh; Steck, Christopher

    2015-01-01

    In this work we present the synthesis, characterization and application of a series of additive and dopant free hole transport materials (HTM) for solid-state perovskite-based solar cells. Newly synthesized HTMs showed strong absorption in the visible spectral range and suitable HOMO-LUMO energy levels for the application for methylammonium lead(II) iodide (CH3NH3PbI3) perovskite. Dopant-free perovskite solar cells have been fabricated using CH3NH3PbI3 perovskite and the newly synthesized HTM...

  11. Design of solar cell materials via soft X-ray spectroscopy

    DEFF Research Database (Denmark)

    Himpsel, F.J.; Cook, P.L.; de la Torre, G.;

    2013-01-01

    This overview illustrates how spectroscopy with soft X-rays can assist the development of new materials and new designs for solar cells. The starting point is the general layout of a solar cell, which consists of a light absorber sandwiched between an electron donor and an electron acceptor. There...... are four relevant energy levels that can be measured with a combination of X-ray absorption spectroscopy and photoelectron spectroscopy, as illustrated for an organic dye as absorber attached to a p-doped diamond film as donor. Systematic measurements of organometallic dyes (phthalocyanines and...

  12. Modelling of Physical, Chemical, and Material Properties of Solid Oxide Fuel Cells

    Directory of Open Access Journals (Sweden)

    Jakub Kupecki

    2015-01-01

    Full Text Available This paper provides a review of modelling techniques applicable for system-level studies to account for physical, chemical, and material properties of solid oxide fuel cells. Functionality of 0D to 3D models is discussed and selected examples are given. Author provides information on typical length scales in evaluation of power systems with solid oxide fuel cells. In each section, proper examples of previous studies done in the field of 0D–3D modelling are recalled and discussed.

  13. Interaction of osteogenic cells with hydroxylapatite implant materials in vitro and in vivo.

    Science.gov (United States)

    Bagambisa, F B; Joos, U; Schilli, W

    1990-01-01

    In a series of scanning electron microscopic studies, the reaction of osteogenic cells to hydroxylapatite (HA) implant materials was investigated in culture and following implantation. Tissue components as found in normal rat and dog bone were identified at the interface in both test systems. In vivo, implant bed cells showed an intimate contact with the HA surfaces. Osteoblasts deposited organic matrix and bone mineral in direct apposition to HA, with no evidence of encapsulation or granulation tissue. The development of such a direct spatial relationship appears to involve mechanisms more encompassing than epitaxis. PMID:2098325

  14. Utilization of mixed oxide materials for solid polymer electrolyte membrane fuel cell

    International Nuclear Information System (INIS)

    Fuel cell technology offers clean, silent and robust sources of energy for our future needs. Among the five common fuel cells widely been used, solid polymer electrolyte membrane fuel cell (SPEFC) gives more advantages in many respects. It is able to generate power more efficiently for both vehicular and stationary in the range of 5 to 500 kW without causing pollution. It's operate at low temperature of 5OoC at an efficiency of 50 to 60 %. Furthermore, it can produce high current density even though it is operating at low temperature (the highest temperature is 90oC) and at the pressure of 600 kPa. It's source of fuel arc hydrogen and oxygen, while discharge very small quantity of water as the product. In this work, the optimization of electrocatalyst for fuel cell electrode using various mixed oxide materials was carried out. The elucidation of active site species that contribute to the performance of the fuel cell was achieved using X-Ray Photoelectron Spectroscopy, X-ray Diffraction and Scanning Electron Microscopy techniques. The result of testing using laboratory scale fuel cell model reveals that the flow rate of fuel gases, the pretreatment of electrocatalysts and the composition of mixed oxide electrocatalysts, play important roles in determining the best performance of the working SPEFC fuel cell system. (Author)

  15. Cell Adhesion Selectivity of Stent Material to improve Bio-functionality by Ion Beam Modification

    International Nuclear Information System (INIS)

    In this study, ion implantation into collagen coated Co-Cr alloy, which is a cheaper material of the artificial stent product comparing with Ti alloy, has been studied to develop small diameter artificial stent by the cell adhesion control. The size of stent was 1.6mm of the diameter and 18mm of the length. The life-time of artificial stent depends on adhesion property of endothelial-cells. We successfully controlled cell adhesion selectivity between endothelial cell and muscle cell by using collagen coated and He+ ion beam irradiated Co-Cr-alloy to apply to artificial stent. But, we did not achieve the inhibition of platelet adhesion, yet by using collagen coating and He+ ion beam irradiation. Based on this study, we have plan to research about separation between collagen coating effect and ion beam effect. Also, we will have more detail analysis of the mechanism of cell attachment. In recent years, ion implantation has been applied to the surface modification of prosthesis to improve blood compatibility and tissue compatibility in field of biomedical application. As well known, bio compatibility was concerned with the cell adhesion selectivity for bio-functionality. The biomedical application of ion beam technology would be used more widely in the future such as catheter and artificial graft

  16. Cell Adhesion Selectivity of Stent Material to improve Bio-functionality by Ion Beam Modification

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jaesang; Park, JUngchan; Jung, Myunghwan; Kim, Yongki [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, Junkyu [Bio alpha., Co. Ltd., Gimhae (Korea, Republic of)

    2014-05-15

    In this study, ion implantation into collagen coated Co-Cr alloy, which is a cheaper material of the artificial stent product comparing with Ti alloy, has been studied to develop small diameter artificial stent by the cell adhesion control. The size of stent was 1.6mm of the diameter and 18mm of the length. The life-time of artificial stent depends on adhesion property of endothelial-cells. We successfully controlled cell adhesion selectivity between endothelial cell and muscle cell by using collagen coated and He{sup +} ion beam irradiated Co-Cr-alloy to apply to artificial stent. But, we did not achieve the inhibition of platelet adhesion, yet by using collagen coating and He{sup +} ion beam irradiation. Based on this study, we have plan to research about separation between collagen coating effect and ion beam effect. Also, we will have more detail analysis of the mechanism of cell attachment. In recent years, ion implantation has been applied to the surface modification of prosthesis to improve blood compatibility and tissue compatibility in field of biomedical application. As well known, bio compatibility was concerned with the cell adhesion selectivity for bio-functionality. The biomedical application of ion beam technology would be used more widely in the future such as catheter and artificial graft.

  17. A review on solar cells from Si-single crystals to porous materials and quantum dots

    Directory of Open Access Journals (Sweden)

    Waheed A. Badawy

    2015-03-01

    Full Text Available Solar energy conversion to electricity through photovoltaics or to useful fuel through photoelectrochemical cells was still a main task for research groups and developments sectors. In this article we are reviewing the development of the different generations of solar cells. The fabrication of solar cells has passed through a large number of improvement steps considering the technological and economic aspects. The first generation solar cells were based on Si wafers, mainly single crystals. Permanent researches on cost reduction and improved solar cell efficiency have led to the marketing of solar modules having 12–16% solar conversion efficiency. Application of polycrystalline Si and other forms of Si have reduced the cost but on the expense of the solar conversion efficiency. The second generation solar cells were based on thin film technology. Thin films of amorphous Si, CIS (copper–indium–selenide and t-Si were employed. Solar conversion efficiencies of about 12% have been achieved with a remarkable cost reduction. The third generation solar cells are based on nano-crystals and nano-porous materials. An advanced photovoltaic cell, originally developed for satellites with solar conversion efficiency of 37.3%, based on concentration of the solar spectrum up to 400 suns was developed. It is based on extremely thin concentration cells. New sensitizer or semiconductor systems are necessary to broaden the photo-response in solar spectrum. Hybrids of solar and conventional devices may provide an interim benefit in seeking economically valuable devices. New quantum dot solar cells based on CdSe–TiO2 architecture have been developed.

  18. A review on synthesis and characterization of solid acid materials for fuel cell applications

    Science.gov (United States)

    Mohammad, Norsyahida; Mohamad, Abu Bakar; Kadhum, Abdul Amir H.; Loh, Kee Shyuan

    2016-08-01

    Solid acids emerged as an electrolyte material for application in fuel cells due to their high protonic conductivity and stability at high temperatures between 100 °C and 250 °C. This paper gives an overview of the different solid acid materials and their properties, such as high protonic conductivity and thermal stability, in relation to phase transitions and mechanisms of proton transport. Various solid acid synthesis methods including aqueous and dry mixing, electrospinning, sol-gel, impregnation and thin-film casting will be discussed, and the impact of synthesis methods on the properties of solid acids will be highlighted. The properties of solid acids synthesized as either single crystals and or polycrystalline powders were identified via X-ray diffraction, nuclear magnetic resonance, thermal analyses, optical microscopy and infrared spectroscopy. A selection of electrolyte-electrode assembly methods and the performance of solid acid fuel cell prototypes are also reviewed.

  19. Electrodes and electrochemical storage cells utilizing tin-modified active materials

    Science.gov (United States)

    Anani, Anaba; Johnson, John; Lim, Hong S.; Reilly, James; Schwarz, Ricardo; Srinivasan, Supramaniam

    1995-01-01

    An electrode has a substrate and a finely divided active material on the substrate. The active material is ANi.sub.x-y-z Co.sub.y Sn.sub.z, wherein A is a mischmetal or La.sub.1-w M.sub.w, M is Ce, Nd, or Zr, w is from about 0.05 to about 1.0, x is from about 4.5 to about 5.5, y is from 0 to about 3.0, and z is from about 0.05 to about 0.5. An electrochemical storage cell utilizes such an electrode as the anode. The storage cell further has a cathode, a separator between the cathode and the anode, and an electrolyte.

  20. Mesoporous nitrogen-rich carbon materials as cathode catalysts in microbial fuel cells

    KAUST Repository

    Ahn, Yongtae

    2014-12-01

    The high cost of the catalyst material used for the oxygen reduction reaction in microbial fuel cell (MFC) cathodes is one of the factors limiting practical applications of this technology. Mesoporous nitrogen-rich carbon (MNC), prepared at different temperatures, was examined as an oxygen reduction catalyst, and compared in performance to Pt in MFCs and electrochemical cells. MNC calcined at 800 °C produced a maximum power density of 979 ± 131 mW m-2 in MFCs, which was 37% higher than that produced using MNC calined at 600 °C (715 ± 152 mW m-2), and only 14% lower than that obtained with Pt (1143 ± 54 mW m-2). The extent of COD removal and coulombic efficiencies were the same for all cathode materials. These results show that MNC could be used as an alternative to Pt in MFCs. © 2014 Elsevier B.V. All rights reserved.

  1. Molecular design and ordering effects in π-functional materials for transistor and solar cell applications

    KAUST Repository

    Beaujuge, Pierre

    2011-12-21

    Organic electronics are broadly anticipated to impact the development of flexible thin-film device technologies. Among these, solution-processable π-conjugated polymers and small molecules are proving particularly promising in field-effect transistors and bulk heterojunction solar cells. This Perspective analyzes some of the most exciting strategies recently suggested in the design and structural organization of π-functional materials for transistor and solar cell applications. Emphasis is placed on the interplay between molecular structure, self-assembling properties, nanoscale and mesoscale ordering, and device efficiency parameters. A critical look at the various approaches used to optimize both materials and device performance is provided to assist in the identification of new directions and further advances. © 2011 American Chemical Society.

  2. Recent development of ceria-based (nano)composite materials for low temperature ceramic fuel cells and electrolyte-free fuel cells

    OpenAIRE

    Fan, Liangdong; Wang, Chengyang; Chen, Mingming; Zhu, Bin

    2013-01-01

    In the last ten years, the research of solid oxide fuel cells (SOFCs) or ceramic fuel cells (CFC) had focused on reducing the working temperature through the development of novel materials, especially the high ionic conductive electrolyte materials. Many progresses on single-phase electrolyte materials with the enhanced ionic conductivity have been made, but they are still far from the criteria of commercialization. The studies of ceria oxide based composite electrolytes give an alternative s...

  3. Influence of surface roughness of carbon materials on human osteoblast-like cell growth

    Czech Academy of Sciences Publication Activity Database

    Starý, V.; Douděrová, M.; Bačáková, Lucie

    2014-01-01

    Roč. 102, č. 6 (2014), s. 1859-1879. ISSN 1549-3296 R&D Projects: GA ČR(CZ) GAP108/10/1858; GA ČR(CZ) GAP108/12/1168; GA AV ČR(CZ) KAN101120701 Institutional support: RVO:67985823 Keywords : carbon materials * roughness * biocompatibility * MG63 cells Subject RIV: EI - Biotechnology ; Bionics Impact factor: 3.369, year: 2014

  4. 17th Workshop on Crystalline Silicon Solar Cells and Modules: Materials and Processes; Workshop Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Sopori, B. L.

    2007-08-01

    The National Center for Photovoltaics sponsored the 17th Workshop on Crystalline Silicon Solar Cells & Modules: Materials and Processes, held in Vail, CO, August 5-8, 2007. This meeting provided a forum for an informal exchange of technical and scientific information between international researchers in the photovoltaic and relevant non-photovoltaic fields. The theme of this year's meeting was 'Expanding Technology for a Future Powered by Si Photovoltaics.'

  5. New materials for intermediate band photovoltaic cells. A theoretical and experimental approach

    OpenAIRE

    Wahnón Benarroch, Perla; Palacios Clemente, Pablo; Aguilera Bonet, Irene; Seminóvski Pérez, Yohanna; Conesa, Jose Carlos; Lucena, Raquel

    2010-01-01

    Density functional theory calculations of certain transition-metal doped semiconductors show a partially occupied relatively narrow band located between valence band and conduction band. These novel systems, containing the metallic band, are called intermediate-band materials. They have enhanced optoelectronic properties which allow an increase in solar energy conversion efficiency of conventional solar cells. We previously proposed III-V, chalcopyrite and sulfide derived compounds show...

  6. Highly Efficient Perovskite Solar Cells Employing an Easily Attainable Bifluorenylidene-Based Hole-Transporting Material.

    Science.gov (United States)

    Rakstys, Kasparas; Saliba, Michael; Gao, Peng; Gratia, Paul; Kamarauskas, Egidijus; Paek, Sanghyun; Jankauskas, Vygintas; Nazeeruddin, Mohammad Khaja

    2016-06-20

    The 4,4'-dimethoxydiphenylamine-substituted 9,9'-bifluorenylidene (KR216) hole transporting material has been synthesized using a straightforward two-step procedure from commercially available and inexpensive starting reagents, mimicking the synthetically challenging 9,9'-spirobifluorene moiety of the well-studied spiro-OMeTAD. A power conversion efficiency of 17.8 % has been reached employing a novel HTM in a perovskite solar cells. PMID:27158924

  7. Laser-Heated Diamond-Anvil Cell (LHDAC) in Materials Science Research

    Institute of Scientific and Technical Information of China (English)

    N.V.Chandra Shekar; P.Ch.Sahu; K.Govinda Rajan

    2003-01-01

    Laser-heated diamond-anvil cell (LHDAC) is emerging as the most suitable, economical and versatile tool for the measurement of a large spectrum of physical properties of materials under extreme pressure and temperature conditions.In this review, the recent developments in the instrumentation, pressure and temperature measurement techniques,results of experimental investigations from the literature were discussed. Also, the future scope of the technique in various avenues of science was explored.

  8. Investigation of test methods, material properties, and processes for solar cell encapsulants. Annual report

    Energy Technology Data Exchange (ETDEWEB)

    Willis, P. B.; Baum, B.

    1979-06-01

    The goal of this program is to identify, evaluate, and recommend encapsulant materials and processes for the production of cost-effective, long-life solar cell modules. During the past year, the technical activities emphasized the reformulation of a commercial grade of ethylene/vinyl acetate copolymer for use as a pottant in solar cell module manufacture. After experimenting with a variety of techniques, a vacuum-bag process was developed and found to be an excellent encapsulation method. Adhesive strengths and primers for the bonding of ethylene/vinyl acetate to superstrate and substrate materials was assessed with encouraging results. The weathering effects on ten other polymers exposed to twelve months of weathering in Arizona, Florida, and under EMMAQUA were evaluated by determination of tensile strengths, elongations, optical transmission, etc. As may be expected, the best overall retention of mechanical properties is found for the fluorocarbon polymers, especially FEP. Hard coatings containing ultraviolet absorbers were investigated for the purpose of providing a soil resistant surface and additional weathering stability to the soft EVA pottant. Corrosion studies using a standard salt spray test were used to determine the degree of protection offered to a variety of metals by encapsulation in EVA pottant. A survey of scrim materials was also conducted. These open hole weaves are intended for use as spacers between the cell and substrate to provide a mechanical barrier, improve insulation resistance and prevent migration of the pigmented pottant over the cell surface. A mechanical engineering analysis of composite structural materials for use as substrates was performed. Results are presented in detail. (WHK)

  9. Perovskite Solar Cells Employing Dopant-Free Organic Hole Transport Materials with Tunable Energy Levels.

    Science.gov (United States)

    Liu, Yongsheng; Hong, Ziruo; Chen, Qi; Chen, Huajun; Chang, Wei-Hsuan; Yang, Yang Michael; Song, Tze-Bin; Yang, Yang

    2016-01-20

    Conjugated small-molecule hole-transport materials (HTMs) with tunable energy levels are designed and synthesized for efficient perovskite solar cells. A champion device with efficiency of 16.2% is demonstrated using a dopant-free DERDTS-TBDT HTM, while the DORDTS-DFBT-HTM-based device shows an inferior performance of 6.2% due to its low hole mobility and unmatched HOMO level with the valence band of perovskite film. PMID:26588665

  10. Investigation of test methods, material properties, and processes for solar cell encapsulants. Seventh annual report

    Energy Technology Data Exchange (ETDEWEB)

    Willis, P.B.

    1983-01-01

    The goal of the program is to identify and evaluate encapsulation materials and processes for the protection of silicon solar cells for service in a terrestrial environment. Aging and degradation studies were performed including: thermal aging, sunlamp exposures, aging in controlled environment reactors and outdoor photothermal aging devices, and metal catalyzed degradation. Other tests addressed water absorption, primers and adhesives, soiling experiments, and corrosion protection. (LEW)

  11. Laser parameters for silicon solar cell processing: a simulation of heat transfer and material modification

    Science.gov (United States)

    Baier, T.; Glaeser, G.; Wanka, H.

    2012-10-01

    In this paper we present a simple technique for approximating laser process parameters needed for laser processing of crystalline silicon solar cells. The calculation computes the changes of silicon material properties during the time of laser-material interaction. As the laser pulse energy modifies optical and thermal properties of silicon, the chronological segmentation illustrates the temperature rise within the irradiated volume and indicates the time needed for melting or evaporation. Depending on the desired material modification, commercially available laser sources are analyzed regarding their process suitability. Simulating the laser system performance reveals its theoretical output and determines its expected efficiency. Simulations in this paper correlate well to experimental data and are done for different fields of interest: a) ablation rate during laser drilling for EWT cells, using IR wavelengths in the order of 1 μs b) depth and width of laser grooves as used for Laser Grooved Buried Contact cells (LGBC) or edge isolation, using wavelengths in the IR and VIS c) process windows during selective laser doping with 532 nm using PSG as sole phosphorous source d) laser parameters needed for Laser-Fired Contacts (LFC).

  12. Kelvin probe force microscopy for the nano scale characterization of chalcopyrite solar cell materials and devices

    International Nuclear Information System (INIS)

    Kelvin probe force microscopy allows to determine not only the surface topography as does atomic force microscopy, but in addition also delivers images of the surface work function on a nanometer scale. Operation in ultrahigh vacuum improves the lateral and energy resolution and allows to obtain absolute work function values. In this paper we will introduce the method and give examples for the application to solar cell materials and devices. We review examples where the surface of an oriented CuGaSe2 film showed distinct work function values for differently oriented facets of single grains, with differences as high as 250 meV, possibly affecting the power conversion efficiency of a solar cell. A cross-sectional study of a complete solar cell device based on the CuGaSe2 absorber material revealed the formation of an additional MoSex layer between the Mo back contact and the absorber. We will present results of measurements at individual grain boundaries of the absorber material. Furthermore, band bending effects at these grain boundaries are discussed and compared to results from transport studies

  13. Development of removal methods of radioactive ruthenium by using the column packed with cell materials

    International Nuclear Information System (INIS)

    Ruthenium is an element of various valencies and present in many chemical species of nitro-nitrosyl complexes in nitric acid or in solutions containing nitrates. Since radioactive ruthenium (103Ru, 106Ru) of those chamical species is contained in the wastes occurred on the fuel reprocessing by Purex method and others, it is one of the nuclides which are most difficult to be removed by the conventional methods of the radioactive waste treatments. It was found that this nuclide was effectively removed by passing the waste solution through a column packed with the mixture of powder of anode and cathode materials and depolarizers used in the electric cells. The typical mixtures were zinc-charcoal, zinc.palladium-charcoal, zinc-manganese dioxide.charcoal and zinc-carbon fluoride.charcoal. These column methods showed a surpassing removel efficiency for 106Ru complexes and fisson products. The decontamination factors of radioactive ruthenium were 104 for all kinds of ruthenium complexes and 102 for the species not easily removed by the conventional methods. It was also found that the concentrations of 239Pu, U, 144ce, 155Eu, and 125Sb in the waste could be decreased to that below the limits of detection by the cell material columns. Because 106Ru of chemical species which was difficult to be removed by conventional methods could be efficiently separated from the waste solutions, it was concluded that the columns packed with cell materials are valuable tools in the radioactive waste treatments. (author)

  14. Analytical study of pulsed laser irradiation on some materials used for photovoltaic cells on satellites

    Science.gov (United States)

    Abd El-Hameed, Afaf M.

    2015-12-01

    The present research concerns on the study of laser-powered solar panels used for space applications. A mathematical model representing the laser effects on semiconductors has been developed. The temperature behavior and heat flow on the surface and through a slab has been studied after exposed to nano-second pulsed laser. The model is applied on two different types of common active semiconductor materials that used for photovoltaic cells fabrication as silicon (Si), and gallium arsenide (GaAs). These materials are used for receivers' manufacture for laser beamed power in space. Various values of time are estimated to clarify the heat flow through the material sample and generated under the effects of pulsed laser irradiation. These effects are theoretically studied in order to determine the performance limits of the solar cells when they are powered by laser radiation during the satellite eclipse. Moreover, the obtained results are carried out to optimize conversion efficiency of photovoltaic cells and may be helpful to give more explanation for layout of the light-electricity space systems.

  15. Application of ATR-FTIR Spectroscopy to Compare the Cell Materials of Wood Decay Fungi with Wood Mould Fungi

    OpenAIRE

    Barun Shankar Gupta; Bjørn Petter Jelle; Tao Gao

    2015-01-01

    Wood fungi create vast damage among standing trees and all types of wood materials. The objectives of this study are to (a) characterize the cell materials of two major wood decay fungi (Basidiomycota), namely, Trametes versicolor and Postia placenta, and (b) compare the cell materials of decay fungi with four wood mould fungi (Ascomycota), namely, Aureobasidium pullulans, Alternaria alternata, Cladosporium cladosporioides, and Ulocladium atrum. Fourier transform infrared (FTIR) spectroscopy ...

  16. Converting environmentally hazardous materials into clean energy using a novel nanostructured photoelectrochemical fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Gan, Yong X., E-mail: yong.gan@utoledo.edu [Department of Mechanical, Industrial and Manufacturing Engineering, College of Engineering, University of Toledo, Toledo, OH 43606 (United States); Gan, Bo J. [Ottawa Hills High School, 2532 Evergreen Road, Toledo, OH 43606 (United States); Clark, Evan; Su, Lusheng [Department of Mechanical, Industrial and Manufacturing Engineering, College of Engineering, University of Toledo, Toledo, OH 43606 (United States); Zhang, Lihua [Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2012-09-15

    Highlights: ► A photoelectrochemical fuel cell has been made from TiO{sub 2} nanotubes. ► The fuel cell decomposes environmentally hazardous materials to produce electricity. ► Doping the anode with a transition metal oxide increases the visible light sensitivity. ► Loading the anode with a conducting polymer enhances the visible light absorption. -- Abstract: In this work, a novel photoelectrochemical fuel cell consisting of a titanium dioxide nanotube array photosensitive anode and a platinum cathode was made for decomposing environmentally hazardous materials to produce electricity and clean fuel. Titanium dioxide nanotubes (TiO{sub 2} NTs) were prepared via electrochemical oxidation of pure Ti in an ammonium fluoride and glycerol-containing solution. Scanning electron microscopy was used to analyze the morphology of the nanotubes. The average diameter, wall thickness and length of the as-prepared TiO{sub 2} NTs were determined. The photosensitive anode made from the highly ordered TiO{sub 2} NTs has good photo-catalytic property, as proven by the decomposition tests on urea, ammonia, sodium sulfide and automobile engine coolant under ultraviolet (UV) radiation. To improve the efficiency of the fuel cell, doping the TiO{sub 2} NTs with a transition metal oxide, NiO, was performed and the photosensitivity of the doped anode was tested under visible light irradiation. It is found that the NiO-doped anode is sensitive to visible light. Also found is that polyaniline-doped photosensitive anode can harvest photon energy in the visible light spectrum range much more efficiently than the NiO-doped one. It is concluded that the nanostructured photoelectrochemical fuel cell can generate electricity and clean fuel by decomposing hazardous materials under sunlight.

  17. Converting environmentally hazardous materials into clean energy using a novel nanostructured photoelectrochemical fuel cell

    International Nuclear Information System (INIS)

    Highlights: ► A photoelectrochemical fuel cell has been made from TiO2 nanotubes. ► The fuel cell decomposes environmentally hazardous materials to produce electricity. ► Doping the anode with a transition metal oxide increases the visible light sensitivity. ► Loading the anode with a conducting polymer enhances the visible light absorption. -- Abstract: In this work, a novel photoelectrochemical fuel cell consisting of a titanium dioxide nanotube array photosensitive anode and a platinum cathode was made for decomposing environmentally hazardous materials to produce electricity and clean fuel. Titanium dioxide nanotubes (TiO2 NTs) were prepared via electrochemical oxidation of pure Ti in an ammonium fluoride and glycerol-containing solution. Scanning electron microscopy was used to analyze the morphology of the nanotubes. The average diameter, wall thickness and length of the as-prepared TiO2 NTs were determined. The photosensitive anode made from the highly ordered TiO2 NTs has good photo-catalytic property, as proven by the decomposition tests on urea, ammonia, sodium sulfide and automobile engine coolant under ultraviolet (UV) radiation. To improve the efficiency of the fuel cell, doping the TiO2 NTs with a transition metal oxide, NiO, was performed and the photosensitivity of the doped anode was tested under visible light irradiation. It is found that the NiO-doped anode is sensitive to visible light. Also found is that polyaniline-doped photosensitive anode can harvest photon energy in the visible light spectrum range much more efficiently than the NiO-doped one. It is concluded that the nanostructured photoelectrochemical fuel cell can generate electricity and clean fuel by decomposing hazardous materials under sunlight.

  18. Advanced silk material spun by a transgenic silkworm promotes cell proliferation for biomedical application.

    Science.gov (United States)

    Wang, Feng; Xu, Hanfu; Wang, Yuancheng; Wang, Riyuan; Yuan, Lin; Ding, Huan; Song, Chunnuan; Ma, Sanyuan; Peng, Zhixin; Peng, Zhangchuan; Zhao, Ping; Xia, Qingyou

    2014-12-01

    Natural silk fiber spun by the silkworm Bombyx mori is widely used not only for textile materials, but also for biofunctional materials. In the present study, we genetically engineered an advanced silk material, named hSFSV, using a transgenic silkworm, in which the recombinant human acidic fibroblast growth factor (hFGF1) protein was specifically synthesized in the middle silk gland and secreted into the sericin layer to surround the silk fiber using our previously optimized sericin1 expression system. The content of the recombinant hFGF1 in the hSFSV silk was estimated to be approximate 0.07% of the cocoon shell weight. The mechanical properties of hSFSV raw silk fiber were enhanced slightly compared to those of the wild-type raw silk fiber, probably due to the presence of the recombinant of hFGF1 in the sericin layer. Remarkably, the hSFSV raw silk significantly stimulated the cell growth and proliferation of NIH/3T3 mouse embryonic fibroblast cells, suggesting that the mitogenic activity of recombinant hFGF1 was well maintained and functioned in the sericin layer of hSFSV raw silk. These results show that the genetically engineered raw silk hSFSV could be used directly as a fine biomedical material for mass application. In addition, the strategy whereby functional recombinant proteins are expressed in the sericin layer of silk might be used to create more genetically engineered silks with various biofunctions and applications. PMID:24980060

  19. Nanotemplated platinum fuel cell catalysts and copper-tin lithium battery anode materials for microenergy devices

    Energy Technology Data Exchange (ETDEWEB)

    Rohan, J.F., E-mail: james.rohan@tyndall.ie [Tyndall National Institute, University College Cork, Lee Maltings, Cork (Ireland); Hasan, M.; Holubowitch, N. [Tyndall National Institute, University College Cork, Lee Maltings, Cork (Ireland)

    2011-11-01

    Highlights: > Anodic Aluminum oxide formation on Si substrate. > High density nanotemplated Pt catalyst on Si for integrated energy and electronics. > CuSn alloy deposition from a single, high efficiency methanesulfonate plating bath. > Nanotemplated CuSn Li anode electrodes with high capacity retention. - Abstract: Nanotemplated materials have significant potential for applications in energy conversion and storage devices due to their unique physical properties. Nanostructured materials provide additional electrode surface area beneficial for energy conversion or storage applications with short path lengths for electronic and ionic transport and thus the possibility of higher reaction rates. We report on the use of controlled growth of metal and alloy electrodeposited templated nanostructures for energy applications. Anodic aluminium oxide templates fabricated on Si for energy materials integration with electronic devices and their use for fuel cell and battery materials deposition is discussed. Nanostructured Pt anode catalysts for methanol fuel cells are shown. Templated CuSn alloy anodes that possess high capacity retention with cycling for lithium microbattery integration are also presented.

  20. Full potential of radial junction Si thin film solar cells with advanced junction materials and design

    Science.gov (United States)

    Qian, Shengyi; Misra, Soumyadeep; Lu, Jiawen; Yu, Zhongwei; Yu, Linwei; Xu, Jun; Wang, Junzhuan; Xu, Ling; Shi, Yi; Chen, Kunji; Roca i Cabarrocas, Pere

    2015-07-01

    Combining advanced materials and junction design in nanowire-based thin film solar cells requires a different thinking of the optimization strategy, which is critical to fulfill the potential of nano-structured photovoltaics. Based on a comprehensive knowledge of the junction materials involved in the multilayer stack, we demonstrate here, in both experimental and theoretical manners, the potential of hydrogenated amorphous Si (a-Si:H) thin film solar cells in a radial junction (RJ) configuration. Resting upon a solid experimental basis, we also assess a more advanced tandem RJ structure with radially stacking a-Si:H/nanocrystalline Si (nc-Si:H) PIN junctions, and show that a balanced photo-current generation with a short circuit current density of Jsc = 14.2 mA/cm2 can be achieved in a tandem RJ cell, while reducing the expensive nc-Si:H absorber thickness from 1-3 μ m (in planar tandem cells) to only 120 nm. These results provide a clearly charted route towards a high performance Si thin film photovoltaics.

  1. Enhanced light harvesting of dye-sensitized solar cells with up/down conversion materials

    International Nuclear Information System (INIS)

    Rare-earth doped ZnO up/down-conversion materials were prepared and introduced into photoelectrodes to enhance the photovoltaic efficiency of dye-sensitized solar cells. In this paper, we achieved a optimal efficiency of 5.13% with the incorporation of ZnO:Eu3+,Tb3+ and ZnO:Er3+, Yb3+, which is about 70% higher than that of dye-sensitized solar cells based on pure TiO2. This is probably due to the enhancement of light harvesting via converting ultraviolet and near infrared radiation to visible emission by downconversion and upconversion luminescence process, respectively. In addition, the ZnO:Eu3+,Tb3+ film acted as a blocking layer inhibit the charge recombination, suppressing the dark current for DSSCs. Results indicate that the ZnO:Eu3+,Tb3+/TiO2:ZnO:Er3+, Yb3+ double composite layers can obviously improve the efficiency of dye-sensitized solar cells, and the combine of the up and down conversion materials is an effective method to extend the response both to ultraviolet and near-infrared radiation in dye-sensitized solar cells

  2. Ultrathin Cu2O as an efficient inorganic hole transporting material for perovskite solar cells

    Science.gov (United States)

    Yu, Weili; Li, Feng; Wang, Hong; Alarousu, Erkki; Chen, Yin; Lin, Bin; Wang, Lingfei; Hedhili, Mohamed Nejib; Li, Yangyang; Wu, Kewei; Wang, Xianbin; Mohammed, Omar F.; Wu, Tom

    2016-03-01

    We demonstrate that ultrathin P-type Cu2O thin films fabricated by a facile thermal oxidation method can serve as a promising hole-transporting material in perovskite solar cells. Following a two-step method, inorganic-organic hybrid perovskite solar cells were fabricated and a power conversion efficiency of 11.0% was achieved. We found that the thickness and properties of Cu2O layers must be precisely tuned in order to achieve the optimal solar cell performance. The good performance of such perovskite solar cells can be attributed to the unique properties of ultrathin Cu2O, including high hole mobility, good energy level alignment with CH3NH3PbI3, and longer lifetime of photo-excited carriers. Combining the merits of low cost, facile synthesis, and high device performance, ultrathin Cu2O films fabricated via thermal oxidation hold promise for facilitating the developments of industrial-scale perovskite solar cells.We demonstrate that ultrathin P-type Cu2O thin films fabricated by a facile thermal oxidation method can serve as a promising hole-transporting material in perovskite solar cells. Following a two-step method, inorganic-organic hybrid perovskite solar cells were fabricated and a power conversion efficiency of 11.0% was achieved. We found that the thickness and properties of Cu2O layers must be precisely tuned in order to achieve the optimal solar cell performance. The good performance of such perovskite solar cells can be attributed to the unique properties of ultrathin Cu2O, including high hole mobility, good energy level alignment with CH3NH3PbI3, and longer lifetime of photo-excited carriers. Combining the merits of low cost, facile synthesis, and high device performance, ultrathin Cu2O films fabricated via thermal oxidation hold promise for facilitating the developments of industrial-scale perovskite solar cells. Electronic supplementary information (ESI) available: Experimental details, AFM images, XRD, hysteresis, XPS, EDAX, device stability and

  3. An investigation into carbon nanostructured materials as catalyst support in proton exchange membrane fuel cells

    DEFF Research Database (Denmark)

    Veltzé, Sune

    Polymer electrolyte fuel cells (PEFCs) are among the key research areas concerning clean cost-effective energy. Carbon nano fibres (CNF), single walled carbon nano tubes (SWCNT), multi walled carbon nano tubes (MWCNT) and other related materials are among the possible successors to standard carbon...... than carbon blacks. Even then the possible durability of the platinum containing catalyst is a major concern for fuel cell degradation during operation. In order to evaluate platinum containing electrocatalysts for proton exchange membrane fuel cells (PEMFC), the rotating disc electrode (RDE) and...... rotating ring disc electrode (RRDE) thin-film application method is an easy and direct method to evaluate the kinetics of the catalyst for specific reactions.This is due to the RDE and RRDE very well described hydrodynamics, and hence has very well defined flow properties of the electrolyte. By using the...

  4. Exposure to Carbon Nanotube Material: Assessment of Nanotube Cytotoxicity Using Human Keratinocyte Cells

    Science.gov (United States)

    Shvedova, Anna A.; Castranova, Vincent; Kisin, Elena R.; Schwegler-Berry, Diane; Murray, Ashley R.; Gandelsman, Vadim Z.; Maynard, Andrew; Baron, Paul

    2003-01-01

    Carbon nanotubes are new members of carbon allotropes similar to fullerenes and graphite. Because of their unique electrical, mechanical, and thermal properties, carbon nanotubes are important for novel applications in the electronics, aerospace, and computer industries. Exposure to graphite and carbon materials has been associated with increased incidence of skin diseases, such as carbon fiber dermatitis, hyperkeratosis, and naevi. We investigated adverse effects of single-wall carbon nanotubes (SWCNT) using a cell culture of immortalized human epidermal keratinocytes (HaCaT). After 18 h of exposure of HaCaT to SWCNT, oxidative stress and cellular toxicity were indicated by formation of free radicals, accumulation of peroxidative products, antioxidant depletion, and loss of cell viability. Exposure to SWCNT also resulted in ultrastructural and morphological changes in cultured skin cells. These data indicate that dermal exposure to unrefined SWCNT may lead to dermal toxicity due to accelerated oxidative stress in the skin of exposed workers.

  5. Enhanced Photovoltaic Performance with Carbon Nanotubes Incorporating into Hole Transport Materials for Perovskite Solar Cells

    Science.gov (United States)

    Wang, Junxia; Li, Jingling; Xu, Xueqing; Xu, Gang; Shen, Honglie

    2016-06-01

    In an attempt to further enhance the photovoltaic performance of perovskite solar cells (PSCs) fabricated by spray deposition under ambient conditions, carbon nanotubes (CNTs) are introduced for incorporation into hole transport materials (HTM). The effect of CNT category and length on the efficiency of the perovskite solar cell for incorporation into HTM is investigated. The enhanced photovoltaic performance is achieved in multi-walled carbon nanotubes (MWCNTs) with the shortest length. The efficiency of acid-treated MWCNT-based cells is improved compared to that of purified MWCNTs due to the better dispersibility and the π-π interaction between the -COOH group and spiro-OMeTAD. As the volume ratio of the spiro-OMeTAD and spiro/MWCNTs mixture is 2:2 or 3:1, the highest power conversion efficiency (PCE) of PSCs containing MWCNTs reaches 8.7% with the enhanced short-circuit current density (J sc) and open-circuit voltage (V oc).

  6. Novel wide band gap materials for highly efficient thin film tandem solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Brian E. Hardin, Stephen T. Connor, Craig H. Peters

    2012-06-11

    Tandem solar cells (TSCs), which use two or more materials to absorb sunlight, have achieved power conversion efficiencies of >25% versus 11-20% for commercialized single junction solar cell modules. The key to widespread commercialization of TSCs is to develop the wide-band, top solar cell that is both cheap to fabricate and has a high open-circuit voltage (i.e. >1V). Previous work in TSCs has generally focused on using expensive processing techniques with slow growth rates resulting in costs that are two orders of magnitude too expensive to be used in conventional solar cell modules. The objective of the PLANT PV proposal was to investigate the feasibility of using Ag(In,Ga)Se2 (AIGS) as the wide-bandgap absorber in the top cell of a thin film tandem solar cell (TSC). Despite being studied by very few in the solar community, AIGS solar cells have achieved one of the highest open-circuit voltages within the chalcogenide material family with a Voc of 949mV when grown with an expensive processing technique (i.e. Molecular Beam Epitaxy). PLANT PV's goal in Phase I of the DOE SBIR was to 1) develop the chemistry to grow AIGS thin films via solution processing techniques to reduce costs and 2) fabricate new device architectures with high open-circuit voltage to produce full tandem solar cells in Phase II. PLANT PV attempted to translate solution processing chemistries that were successful in producing >12% efficient Cu(In,Ga)Se2 solar cells by replacing copper compounds with silver. The main thrust of the research was to determine if it was possible to make high quality AIGS thin films using solution processing and to fully characterize the materials properties. PLANT PV developed several different types of silver compounds in an attempt to fabricate high quality thin films from solution. We found that silver compounds that were similar to the copper based system did not result in high quality thin films. PLANT PV was able to deposit AIGS thin films using a

  7. The transport pathway of labelled Mycena osmundicola and assimilated labelled materials in the embryonic cells of Gastrodia elata

    International Nuclear Information System (INIS)

    Mycena osmundicola Lange. was labelled by 3H-glucose and the seeds of Gastrodia elata B1. were sown on the saprophytic leaves of labelled M. osmundicola. By means of autoradiography, it is found that the labelled M. osmundicola infected embryonic cells of G. elata only through the suspensor cells. In the embryonic cells of G. elata the assimilated labelled materials entered into the cells by the wall of cell. After the protocorm formed, the assimilated labelled materials were transferred by the vascular tissue of G. elata

  8. Polymer solar cells - Non toxic processing and stable polymer photovoltaic materials

    Energy Technology Data Exchange (ETDEWEB)

    Soendergaard, R.

    2012-07-01

    The field of polymer solar cell has experienced enormous progress in the previous years, with efficiencies of small scale devices (approx1 mm2) now exceeding 8%. However, if the polymer solar cell is to achieve success as a renewable energy resource, mass production of sufficiently stable and efficient cell must be achieved. For a continuous success it is therefore essential to transfer the accomplishments from the laboratory to large scale facilities for actual production. In order to do so, several issues have to be approached. Among these are more environmentally friendly processing and development of more stable materials. The field of polymer solar cells has evolved around the use of toxic and carcinogenic solvents like chloroform, benzene, toluene, chlorobenzene, dichlorobenzene and xylene. As large scale production of organic solar cells is envisaged to production volumes corresponding to several GW{sub peek}, this is not a suitable approach from neither a production nor environmental point of view. As a consequence new materials, which can be processed from more environmentally friendly solvents (preferably water), need to be developed. In this thesis, the issue has been approached through synthesis of polymers carrying water coordinating side chains which allow for processing from semi-aqueous solution. A series of different side chains were synthesized and incorporated into the final polymers as thermocleavable tertiary esters. Using a cleavable side chain induces stability to solar cells as it slows down diffusion though the active layer, but just as important it renders the layer insoluble. This allows for further processing, using the same solvent, without dissolving already processed layers, and resulted in the first ever reported solar cells where all layers are processed from aqueous or semi-aqueous solution. As previously mentioned many advantages can be achieved by use of thermocleavable materials. Unfortunately the cleavage temperatures are too

  9. Photothermally induced bromination of carbon/polymer bipolar plate materials for fuel cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Schade, Martin; Franzka, Steffen [Fakultät für Chemie, Universität Duisburg-Essen, 45117 Essen (Germany); Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Carl-Benz-Straße 199, 47057 Duisburg (Germany); Cappuccio, Franco; Peinecke, Volker; Heinzel, Angelika [Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Carl-Benz-Straße 199, 47057 Duisburg (Germany); Zentrum für BrennstoffzellenTechnik (ZBT), Carl-Benz-Straße 201, 47057 Duisburg (Germany); Hartmann, Nils, E-mail: nils.hartmann@uni-due.de [Fakultät für Chemie, Universität Duisburg-Essen, 45117 Essen (Germany); Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Carl-Benz-Straße 199, 47057 Duisburg (Germany)

    2015-05-01

    Graphical abstract: - Highlights: • Photothermal laser bromination of carbon/polymer materials is demonstrated. • Using a microfocused laser functionalized domains with diameters of 5 μm and 100 μm and more can be fabricated. • Bromine groups can be transformed in a variety of other chemical functionalities, i.e. amine groups. • Depending on the chemical functionality, the local chemical affinity and wettability is changed. • The routine can be applied to standard bipolar plate materials used for fuel cell applications. - Abstract: A facile photothermal procedure for direct functionalization of carbon/polymer bipolar plate materials is demonstrated. Through irradiation with a microfocused beam of an Ar{sup +}-laser at λ = 514 nm in gaseous bromine and distinct laser powers and pulse lengths local bromination of the carbon/polymer material takes place. At a 1/e spot diameter of 2.1 μm, functionalized surface areas with diameters down to 5 μm are fabricated. In complementary experiments large-area bromination is investigated using an ordinary tungsten lamp. For characterization contact angle goniometry, X-ray photoelectron spectroscopy and electron microscopy in conjunction with labeling techniques are employed. After irradiation bromine groups can easily be substituted by other chemical functionalities, e.g. azide and amine groups. This provides a facile approach in order to fabricate surface patterns and gradient structures with varying wetting characteristics. Mechanistic aspects and prospects of photothermal routines in micropatterning of carbon/polymer materials are discussed.

  10. High-Fidelity Generalization Method of Cells for Inelastic Periodic Multiphase Materials

    Science.gov (United States)

    Aboudi, Jacob; Pindera, Marek-Jerzy; Arnold, Steven M.

    2002-01-01

    An extension of a recently-developed linear thermoelastic theory for multiphase periodic materials is presented which admits inelastic behavior of the constituent phases. The extended theory is capable of accurately estimating both the effective inelastic response of a periodic multiphase composite and the local stress and strain fields in the individual phases. The model is presently limited to materials characterized by constituent phases that are continuous in one direction, but arbitrarily distributed within the repeating unit cell which characterizes the material's periodic microstructure. The model's analytical framework is based on the homogenization technique for periodic media, but the method of solution for the local displacement and stress fields borrows concepts previously employed by the authors in constructing the higher-order theory for functionally graded materials, in contrast with the standard finite-element solution method typically used in conjunction with the homogenization technique. The present approach produces a closed-form macroscopic constitutive equation for a periodic multiphase material valid for both uniaxial and multiaxial loading. The model's predictive accuracy in generating both the effective inelastic stress-strain response and the local stress said inelastic strain fields is demonstrated by comparison with the results of an analytical inelastic solution for the axisymmetric and axial shear response of a unidirectional composite based on the concentric cylinder model, and with finite-element results for transverse loading.

  11. Investigation of test methods, material properties, and processes for solar cell encapsulants. Annual report

    Energy Technology Data Exchange (ETDEWEB)

    Willis, P. B.; Baum, B.; White, R. A.

    1978-06-01

    Springborn Laboratories is engaged in a study of evaluating potentially useful encapsulating materials for the encapsulation task of the Low-Cost Solar Array project (LSA) funded by the Department of Energy. The goal of this program is to identify, evaluate, and recommend encapsulant materials (other than glass) and processes for the production of cost-effective, long-life photovoltaic solar modules. The results of an investigation of solar module encapsulation systems applicable to the Low-Cost Solar Array project 1986 cost and performance goals are presented. The 1986 cost goal for a 20 year life solar cell module is $0.50 per watt or $5 per square foot (in 1975 dollars). Out of this cost goal, $0.25 per square foot is currently allocated for the encapsulation in terms of raw materials, exclusive of labor. Assuming the flat-plate collector to be the most efficient module design, six basic construction elements were identified and their specific uses in module construction defined. In order to generate a comparative analysis, a uniform costing basis was established for each element. Extensive surveys into commercially available materials were then conducted in order to identify either general classes or specific products suitable for use for each construction element. The survey results were also useful in revealing price ranges for classes of materials and estimating the cost allocation for each element within the encapsulation cost goal.

  12. A Viable Electrode Material for Use in Microbial Fuel Cells for Tropical Regions

    Directory of Open Access Journals (Sweden)

    Felix Offei

    2016-01-01

    Full Text Available Electrode materials are critical for microbial fuel cells (MFC since they influence the construction and operational costs. This study introduces a simple and efficient electrode material in the form of palm kernel shell activated carbon (AC obtained in tropical regions. The novel introduction of this material is also targeted at introducing an inexpensive and durable electrode material, which can be produced in rural communities to improve the viability of MFCs. The maximum voltage and power density obtained (under 1000 Ω load using an H-shaped MFC with AC as both anode and cathode electrode material was 0.66 V and 1.74 W/m3, respectively. The power generated by AC was as high as 86% of the value obtained with the extensively used carbon paper. Scanning electron microscopy and Denaturing Gradient Gel Electrophoresis (DGGE analysis of AC anode biofilms confirmed that electrogenic bacteria were present on the electrode surface for substrate oxidation and the formation of nanowires.

  13. Photothermally induced bromination of carbon/polymer bipolar plate materials for fuel cell applications

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Photothermal laser bromination of carbon/polymer materials is demonstrated. • Using a microfocused laser functionalized domains with diameters of 5 μm and 100 μm and more can be fabricated. • Bromine groups can be transformed in a variety of other chemical functionalities, i.e. amine groups. • Depending on the chemical functionality, the local chemical affinity and wettability is changed. • The routine can be applied to standard bipolar plate materials used for fuel cell applications. - Abstract: A facile photothermal procedure for direct functionalization of carbon/polymer bipolar plate materials is demonstrated. Through irradiation with a microfocused beam of an Ar+-laser at λ = 514 nm in gaseous bromine and distinct laser powers and pulse lengths local bromination of the carbon/polymer material takes place. At a 1/e spot diameter of 2.1 μm, functionalized surface areas with diameters down to 5 μm are fabricated. In complementary experiments large-area bromination is investigated using an ordinary tungsten lamp. For characterization contact angle goniometry, X-ray photoelectron spectroscopy and electron microscopy in conjunction with labeling techniques are employed. After irradiation bromine groups can easily be substituted by other chemical functionalities, e.g. azide and amine groups. This provides a facile approach in order to fabricate surface patterns and gradient structures with varying wetting characteristics. Mechanistic aspects and prospects of photothermal routines in micropatterning of carbon/polymer materials are discussed

  14. Recycling of high purity selenium from CIGS solar cell waste materials

    International Nuclear Information System (INIS)

    Highlights: • A new method for recycling of selenium from CIGS solar cell materials is presented. • Separation of selenium as selenium dioxide after heating in oxygen atmosphere. • Complete selenium separation after oxidation of <63 μm particles at 800 °C for 1 h. • After reduction of selenium dioxide the selenium purity was higher than 99.999 wt%. - Abstract: Copper indium gallium diselenide (CIGS) is a promising material in thin film solar cell production. To make CIGS solar cells more competitive, both economically and environmentally, in comparison to other energy sources, methods for recycling are needed. In addition to the generally high price of the material, significant amounts of the metals are lost in the manufacturing process. The feasibility of recycling selenium from CIGS through oxidation at elevated temperatures was therefore examined. During oxidation gaseous selenium dioxide was formed and could be separated from the other elements, which remained in solid state. Upon cooling, the selenium dioxide sublimes and can be collected as crystals. After oxidation for 1 h at 800 °C all of the selenium was separated from the CIGS material. Two different reduction methods for reduction of the selenium dioxide to selenium were tested. In the first reduction method an organic molecule was used as the reducing agent in a Riley reaction. In the second reduction method sulphur dioxide gas was used. Both methods resulted in high purity selenium. This proves that the studied selenium separation method could be the first step in a recycling process aimed at the complete separation and recovery of high purity elements from CIGS

  15. Formulation Changes Affect Material Properties and Cell Behavior in HA-Based Hydrogels

    Directory of Open Access Journals (Sweden)

    Thomas Lawyer

    2012-01-01

    Full Text Available To develop and optimize new scaffold materials for tissue engineering applications, it is important to understand how changes to the scaffold affect the cells that will interact with that scaffold. In this study, we used a hyaluronic acid- (HA- based hydrogel as a synthetic extracellular matrix, containing modified HA (CMHA-S, modified gelatin (Gtn-S, and a crosslinker (PEGda. By varying the concentrations of these components, we were able to change the gelation time, enzymatic degradation, and compressive modulus of the hydrogel. These changes also affected fibroblast spreading within the hydrogels and differentially affected the proliferation and metabolic activity of fibroblasts and mesenchymal stem cells (MSCs. In particular, PEGda concentration had the greatest influence on gelation time, compressive modulus, and cell spreading. MSCs appeared to require a longer period of adjustment to the new microenvironment of the hydrogels than fibroblasts. Fibroblasts were able to proliferate in all formulations over the course of two weeks, but MSCs did not. Metabolic activity changed for each cell type during the two weeks depending on the formulation. These results highlight the importance of determining the effect of matrix composition changes on a particular cell type of interest in order to optimize the formulation for a given application.

  16. Optimum dose of 2-hydroxyethyl methacrylate based bonding material on pulp cells toxicity

    Directory of Open Access Journals (Sweden)

    Widya Saraswati

    2010-06-01

    Full Text Available Background: 2-hydroxyethyl methacrylate (HEMA, one type of resins commonly used as bonding base material, is commonly used due to its advantageous chemical characteristics. Several preliminary studies indicated that resin is a material capable to induce damage in dentin-pulp complex. It is necessary to perform further investigation related with its biological safety for hard and soft tissues in oral cavity. Purpose: The author performed an in vitro test to find optimum dose of HEMA resin monomer that may induce toxicity in pulp fibroblast cells. Method: The method of this study was experimental laboratory with post test control group design. Primary cell culture was made from dental pulp fibroblast cells, and was given with HEMA resin bonding material in various concentrations (5 µg/ml–2560 µg/ml, and then subjected to toxicity test (MTT assay. Result: HEMA optimum concentration was 320 µg/ml to induce cytotoxicity in pulp fibroblast cells. Conclusion: The used of HEMA - base bonding material with the concentration of 200 µg/ml may induced pulp fibroblas cell toxicity.Latar belakang: Keberhasilan suatu bahan bonding secara klinis tergantung pada kandungan fisik, kimia dan keamanan secara biologis. HEMA (2-hydroxyethyl methacrylate adalah bahan resin yang paling banyak digunakan karena memiliki sifat fisik-kimia yang baik. Beberapa penelitian pendahuluan menyebutkan bahwa resin merupakan bahan yang mampu menyebabkan gangguan pada kompleks dentin pulpa sehingga perlu dilakukan penelitian lebih lanjut menyangkut segi keamanan secara biologis bagi jaringan keras dan jaringan lunak di rongga mulut. Tujuan: Penelitian ini akan menguji secara in vitro (pada kultur sel fibroblas pulpa gigi untuk mengetahui dosis optimal monomer resin HEMA yang dapat menyebabkan toksisitas pada sel fibroblas pulpa. Metode: Metode penelitian ini adalah eksperimental laboratoris dengan rancangan penelitian post test control group design. Kultur sel primer dibuat dari

  17. Bone cell-material interactions on metal-ion doped polarized hydroxyapatite

    International Nuclear Information System (INIS)

    The objective of this work is to study the influence of Mg2+ and Sr2+ dopants on in vitro bone cell-material interactions of electrically polarized hydroxyapatite [HAp, Ca10(PO4)6(OH)2] ceramics with an aim to achieve additional advantage of matching bone chemistry along with the original benefits of electrical polarization treatment relevant to biomedical applications. To achieve our research objective, commercial phase pure HAp has been doped with MgO, and SrO in single, and binary compositions. All samples have been sintered at 1200 deg. C for 2 h and subsequently polarized using an external d.c. field (2.0 kV/cm) at 400 deg. C for 1 h. Combined addition of 1 wt.% MgO/1 wt.% SrO in HAp has been most beneficial in enhancing the polarizability in which stored charge was 4.19 μC/cm2 compared to pure HAp of 2.23 μC/cm2. Bone cell-material interaction has been studied by culturing with human fetal osteoblast cells (hFOB) for a maximum of 7 days. Scanning electron microscope (SEM) images of cell morphology reveal that favorable surface properties and dopant chemistry lead to good cellular adherence and spreading on negatively charged surfaces of both Sr2+ and Mg2+ doped HAp samples over undoped HAp. MTT assay results at 7 days show the highest viable cell densities on the negatively charged surfaces of binary doped HAp samples, while positive charged doped HAp surfaces exhibit limited cellular growth in comparison to neutral surfaces.

  18. Influence of pressure and silane depletion on microcrystalline silicon material quality and solar cell performance

    International Nuclear Information System (INIS)

    Hydrogenated microcrystalline silicon growth by very high frequency plasma-enhanced chemical vapor deposition is investigated in an industrial-type parallel plate R and D KAI reactor to study the influence of pressure and silane depletion on material quality. Single junction solar cells with intrinsic layers prepared at high pressures and in high silane depletion conditions exhibit remarkable improvements, reaching 8.2% efficiency. Further analyses show that better cell performances are linked to a significant reduction of the bulk defect density in intrinsic layers. These results can be partly attributed to lower ion bombardment energies due to higher pressures and silane depletion conditions, improving the microcrystalline material quality. Layer amorphization with increasing power density is observed at low pressure and in low silane depletion conditions. A simple model for the average ion energy shows that ion energy estimates are consistent with the amorphization process observed experimentally. Finally, the material quality of a novel regime for high rate deposition is reviewed on the basis of these findings

  19. Compatibility between glass sealants and electrode materials of solid oxide fuel cells

    Institute of Scientific and Technical Information of China (English)

    PIAO Jinhua; SUN Kening; Chen Xinbing

    2008-01-01

    BaO-CaO-Al2O3-SiO2-La2O3-B2O3 system glass materials were investigated as sealants for a solid oxide fuel cell (SOFC).The transition temperature (Tg) and the crystal temperature (Td) values decrease greatly with the increase of BaCO3 content when the other components do not change.For the thermal expansion coefficient (TEC) values,the trend is inverse.The sealant has superior thermal expansion coefficient matching properties with La(Sr)MnO3 (LSM) cathode,La(Sr)FeO3 (LSF) cathode,Ni-LDC (La doped CeO2) anode,and Ni-YSZ (yttria stabilized zirconia) cermet anode.The sealant also has superior stability,compatibility,and good bonding characteristic with these electrode materials at 800-900℃.The results indicate that the aluminosilicate system glass sealant possesses superior compatibility with electrode materials of the solid oxide fuel cell.

  20. Electrochemical characterizati on of MnO2 as electrocatalytic energy material for fuel cell electrode

    Institute of Scientific and Technical Information of China (English)

    Subir Paul; Asmita Ghosh

    2015-01-01

    Development of inexpensive non Pt based high electrocatalytic energy materials is the need of the hour for fuel cell electrode to produce clean alternative green energy from synthesized bio alcohol using biomass.MnO2 , electro synthesized at different current density is found to be well performed electrocatalytic material, comparable to Pt, with higher current density, very low overvoltage for the electrochemical oxidation of methanol.From EIS study, the polarization resistance of the coate d MnO2 is found to be much low and electrical double layer capacitance is high, the effect increases with increase in current density of electro deposition.XRD, EDX and AAS analysis confirm the MnO2 depositio n.Them orphology of SEM im agese xhibits an enhanced 3D effective sub strat e area, for elect ro oxidation oft he fuel.A few nano structured grains of the deposite d MnO2 is also observed at higher current density.The fact supports that a high energet ic ine xpensive electroc atalytic material has beenf ound for fu el cell electrodet o synthesis renewable energy from methanol fuel.

  1. Fuel cell membrane materials by chemical grafting of aromatic main-chain polymers

    Energy Technology Data Exchange (ETDEWEB)

    Jannasch, P. [Department of Polymer Science and Engineering, Lund University, P.O. Box 124, SE-221 00 Lund (Sweden)

    2005-04-01

    An extensive world-wide pursuit for new efficient fuel cell membranes materials is currently motivating research on proton-conducting ionomers based on durable aromatic main-chain polymers. In this context, most ionomers have been prepared either by direct sulfonation of polymers, using for example fuming sulfuric acid, or by direct polymerizations using different sulfonated monomers. Far less exploited are chemical grafting reactions carried out to introduce sulfonic acid units, or alternative acidic units, directly on the polymer main-chain, or on side-chains to the polymer main-chain. This versatile method offers very interesting possibilities, not only to control the degree and the site of sulfonation, but also when it comes to manipulating the molecular mobility of the sulfonic acid units and their distance from the polymer main-chain. The length and nature of the grafted units have shown to have a large influence on for example the water-uptake characteristics and conductivity of ionomer membranes, especially at temperatures above 100 C. Grafting can also be used to introduce other useful functions to the polymers, or to crosslink membranes. This paper reviews various grafting reactions carried out on aromatic main-chain polymers, especially polybenzimidazoles and polysulfones, to prepare membrane materials, as well as the characteristics of these materials regarding their use in fuel cells. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

  2. Properties of hydrogel materials used for entrapment of microbial cells in production of fermented beverages.

    Science.gov (United States)

    Navrátil, Marián; Gemeiner, Peter; Klein, Jaroslav; Sturdík, Ernest; Malovíková, Anna; Nahálka, Jozef; Vikartovská, Alica; Dömény, Zoltán; Smogrovicová, Daniela

    2002-05-01

    Approaches using immobilized biological materials are very promising for application in different branches of the food industry, especially in the production of fermented beverages. Materials tested by our team for the process of entrapment belong to the family of charged polysaccharides able to form beaded hydrogels by ionotropic gelation (e.g. alginate, pectate, kappa-carrageenan) and synthetic polymers (e.g. polyvinyl alcohol) forming bead- and lens-shaped hydrogels by thermal sol/gel transition. Concentration of a gel, conditions and instrumentation of gelation process, bead and size distribution, porosity, diffusion properties, mechanical, storage and operational stability, and many other parameters were followed and optimized. Our work has been oriented especially to practical applications of immobilized cells. Brewing yeast cells were successfully immobilized by entrapment materials and used in a process of batch and continual production of beer, including primary and secondary fermentation of wort. Other applications include continual production of ethanol by fermentation of different saccharide substrates (molasses, glucose syrup, wheat hydrolysate), mead and non-alcoholic beverages production. PMID:12066875

  3. Analysis of cathode materials of perovskite structure for solid oxide fuel cells, sofc s

    International Nuclear Information System (INIS)

    Fuel cells directly and efficiently convert the chemical energy of a fuel into electrical energy. Of the various types of fuel cells, the solid oxide (Sofc), combine the advantages in environmentally benign energy generation with fuel flexibility. However, the need for high operating temperatures (800 - 1000 grades C) has resulted in high costs and major challenges in relation to the compatibility the cathode materials. As a result, there have been significant efforts in the development of intermediate temperature Sofc (500 - 700 grades C). A key obstacle for operation in this temperature range is the limited activity of traditional cathode materials for electrochemical reduction oxygen. In this article, the progress of recent years is discussed in cathodes for Sofc perovskite structure (ABO3), more efficient than the traditionally used La1-xSrxMnO3-δ (LSM) or (La, Sr) CoO3. Such is the case of mixed conductors (MIEC) double perovskite structure (A A B2O5+δ) using different doping elements as La, Sr, Fe, Ti, Cr, Sm, Co, Cu, Pr, Nd, Gd, dy, Mn, among others, which could improve the operational performance of existing cathode materials, promoting the development of optimized intermediate temperature Sofc designs. (Author)

  4. Physical cell interactions with their surrounding materials: Mechanics and geometrical factors using microfluidic platforms

    Science.gov (United States)

    Lopez Garcia, Maria Del Carmen

    Microfluidics platforms are employed in: "sperm motion in a microfluidic device" and "mechanical interactions of mammary gland cells with their surrounding three dimensional extra-cellular matrix". Microfluidics has shown promise as a new platform for assisted reproduction. Sperm and fluid motion in microchannels was studied to understand the flow characteristics in the device, how sperm interacted with this flow, and how sperm-oocyte attachment occurs in the device. A threshold fluid velocity was found where sperm transition from traveling with the fluid to a regime in which they can move independently. A population of sperm remained in the inlet well area. There was also the tendency of sperm to travel along surface contours. These observations provide an improved understanding of sperm motion in microchannels and a basis for improved device designs. The effort to understand the development of breast cancer motivates the study of mammary gland cells and their interactions with the extra-cellular matrix. Mammographic density is a risk factor for breast cancer which correlates with collagen density affects cell behavior. Collagen gels with concentrations of 1.3, 2, and 3 mg/mL, were tensile tested to obtain the Young's modulus, E, at low displacement rates of 0.01, 0.1, and 1 mm/min. Local strain measurement in the gage section were used for both strain and strain rate determination. Local strain rates were on the order of cellular generated strain rate. A power law fitting described the relationship between Young's modulus and local strain rate. Mammary gland cells were seeded with collagen and fluorescent beads into microchannels and observed via four-dimensional imaging. The displacements of the beads were used to calculate strains. The Young's modulus due to the rate at which the cell was straining the collagen was obtained from the aforementioned fittings. Three-dimensional elastic theory for an isotropic material was employed to calculate the stress. The

  5. StemBANCC: Governing Access to Material and Data in a Large Stem Cell Research Consortium.

    Science.gov (United States)

    Morrison, Michael; Klein, Christine; Clemann, Nicole; Collier, David A; Hardy, John; Heisserer, Barbara; Cader, M Zameel; Graf, Martin; Kaye, Jane

    2015-10-01

    This paper makes the case for implementing an internal governance framework for sharing materials and data in stem cell research consortia. A governance framework can facilitate a transparent and accountable system while building trust among partner institutions. However, avoiding excessive bureaucracy is essential. The development and implementation of a governance framework for materials and data access in the Stem cells for Biological Assays of Novel drugs and prediCtive toxiCology (StemBANCC) consortium is presented as a practical example. The StemBANCC project is a multi-partner European research consortium, which aims to build a resource of 1,500 well characterised induced pluripotent stem cell (iPSC) lines for in vitro disease modelling and toxicology studies. The project governance framework was developed in two stages. A small working group identified key components of a framework and translated the project legal agreements into a draft policy document. The second phase allowed input from all consortium partners to shape the iterative development of a final policy document that could be agreed by all parties. Careful time management strategies were needed to manage the duration of this component. This part of the process also served as an exploratory space where different options could be proposed, potential gaps in planning identified, and project co-ordination activities specified. PMID:26024842

  6. Inorganic-organic solar cells based on quaternary sulfide as absorber materials.

    Science.gov (United States)

    Hong, Tiantian; Liu, Zhifeng; Yan, Weiguo; Liu, Junqi; Zhang, Xueqi

    2015-12-14

    We report a novel promising quaternary sulfide (CuAgInS) to serve as a semiconductor sensitizer material in the photoelectrochemical field. In this study, CuAgInS (CAIS) sulfide sensitized ZnO nanorods were fabricated on ITO substrates through a facile and low-cost hydrothermal chemical method and applied on photoanodes for solar cells for the first time. The component and stoichiometry were key factors in determining the photoelectric performance of CAIS sulfide, which were controlled by modulating their reaction time. ZnO/Cu0.7Ag0.3InS2 nanoarrays exhibit an enhanced optical and photoelectric performance and the power conversion efficiency of ITO/ZnO/Cu0.7Ag0.3InS2/P3HT/Pt solid-state solar cell was up to 1.80%. The remarkable performance stems from improved electron transfer, a higher efficiency of light-harvesting and appropriate band gap alignment at the interface of the ZnO/Cu0.7Ag0.3InS2 NTs. The research indicates that CAIS as an absorbing material has enormous potential in solar cell systems. PMID:26553746

  7. Enhanced power conversion efficiency of dye-sensitized solar cells assisted with phosphor materials

    Science.gov (United States)

    Lee, Yong-Min; Kim, Dong In; Hwang, Ki-Hwan; Nam, Sang Hun; Boo, Jin-Hyo

    2016-07-01

    Theoretically dye-sensitized solar cells (DSSCs) are high efficiency solar cells. However, DSSCs have lower power conversion efficiency (PCE) than silicon based solar cells. In this study, we use scattering layer and phosphor materials, such as ZrO2 and Zn2SiO4:Mn (Green), to enhance the PCE of DSSCs. The scattering layer and phosphor materials were prepared and used as an effective scattering layer on the transparent TiO2 photoelectrode through the doctor blade method. We confirmed that the scattering layer improves the PCE and J sc due to the enhancement of light harvesting by increasing the scattering and absorbance in the visible range. Under sun illumination AM 1.5 conditions, the PCE of the mesoporous TiO2 based DSSCs was 5.18%. The PCE of the DSSCs with ZrO2 scattering layer was 5.61% and Zn2SiO4:Mn as the scattering layer was enhanced to 5.72%. In order to compare the change in optical properties, DSSCs were measured by EQE, reflectance and PCE. At the same time, FE-SEM and XRD were used to confirm the structural changes in each layer. [Figure not available: see fulltext.

  8. Computational model for nonlinear plasma formation in high NA micromachining of transparent materials and biological cells.

    Science.gov (United States)

    Arnold, C L; Heisterkamp, A; Ertmer, W; Lubatschowski, H

    2007-08-01

    Cell surgery based on ultrashort laser pulses is a fast evolving field in biophotonics. Noninvasive intra cellular dissection at sub-diffraction resolution can be performed within vital cells with very little hazardous effects to adjacent cell organelles. Microscope objectives of high numerical aperture (NA) are used to focus ultrashort pulses to a small spot. Due to the high order of nonlinearity, plasma formation and thus material manipulation is limited to the very focus. Nonetheless nonlinear plasma formation is generally accompanied by a number of additional nonlinear effects like self-focusing and filamentation. These parasitic effects limit the achievable precision and reproducibility of applications. Experimentally it is known that the intensity of these effects decreases with increasing NA of the focusing optics, but the process of nonlinear plasma formation at high NA has not been studied numerically in detail yet. To simulate the interaction of ultrashort laser pulses with transparent materials at high NA a novel nonlinear Schr odinger equation is derived; the multiple rate equation (MRE) model is used to simultaneously calculate the generation of free electrons. Nonparaxial and vectorial effects are taken into account to accurately include tight focusing conditions. Parasitic effects are shown to get stronger and increasingly distortive for NA < 0.9, using water as a model substance for biological soft tissue and cellular constituents. PMID:19547380

  9. Materials, design, and modeling for bipolar/end plates in polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Kumar, Atul

    New vehicle technologies are required to improve upon conventional internal combustion engine technologies. In this regard, the development of fuel cell (polymer electrolyte membrane type) vehicles with improved efficiency and reliability seems promising. However, some technical issues exist that hinder the commercialization of this technology. One such issue is the high cost, volume, and mass of the bipolar/end plates in the polymer electrolyte membrane fuel cell (PEMFC) stack. This research, therefore, focuses on materials, design, and modeling for bipolar/end plates in PEMFC stack. Alternative materials were tested that can replace the conventionally used graphite in the PEMFC stack. With regards to these, a two-cell PEMFC stack was fabricated with SS-316 multi-parallel flow-field (MPFF) designed bipolar/end plates. The stack was run for over 1000 hours and showed no appreciable drop in performance. To enhance the understanding and for determining the effect of operating parameters in PEMFC, a single cell model was developed. The model results agree well with the experimental data. The gas flow-field in bipolar/end plates of the PEMFC was optimized with respect to channel dimensions, channel shape, flow-field design, and flow-field permeability. It was seen that lower the flow-field permeability better is the fuel cell performance. Based on this, the concept of use of metal foams in the gas flow-field was proposed. Experiments were carried out to test the feasibility of metal foams in the gas flow-field of bipolar/end plates in PEMFC stack. Three different porous materials, viz. Ni-Cr metal foam (50 P PI, pores per inch), S S-316 metal foam (20 PPI), and carbon cloth were tested, and the results were compared to the conventional MPFF channel design concept. It was seen that the performance with Ni-Cr metal foam was highest, and decreased in the order of SS-316 metal foam, conventional MPFF design, and carbon cloth. This trend was explained based on the effective

  10. Nanoscale Interfaces in Colloidal Quantum Dot Solar Cells: Physical Insights and Materials Engineering Strategies

    Science.gov (United States)

    Kemp, Kyle Wayne

    With growing global energy demand there will be an increased need for sources of renewable energy such as solar cells. To make these photovoltaic technologies more competitive with conventional energy sources such as coal and natural gas requires further reduction in manufacturing costs that can be realized by solution processing and roll-to-roll printing. Colloidal quantum dots are a bandgap tunable, solution processible, semiconductor material which may offer a path forward to efficient, inexpensive photovoltaics. Despite impressive progress in performance with these materials, there remain limitations in photocarrier collection that must be overcome. This dissertation focuses on the characterization of charge recombination and transport in colloidal quantum dot photovoltaics, and the application of this knowledge to the development of new and better materials. Core-shell, PbS-CdS, quantum dots were investigated in an attempt to achieve better surface passivation and reduce electronic defects which can limit performance. Optimization of this material led to improved open circuit voltage, exceeding 0.6 V for the first time, and record published performance of 6% efficiency. Using temperature-dependent and transient photovoltage measurements we explored the significance of interface recombination on the operation of these devices. Careful engineering of the electrode using atomic layer deposition of ZnO helped lead to better TiO2 substrate materials and allowed us to realize a nearly two-fold reduction in recombination rate and an enhancement upwards of 50 mV in open circuit voltage. Carrier extraction efficiency was studied in these devices using intensity dependent current-voltage data of an operational solar cell. By developing an analytical model to describe recombination loss within the active layer of the device we were able to accurately determine transport lengths ranging up to 90 nm. Transient absorption and photoconductivity techniques were used to study

  11. Phase wettability and microstructural evolution in solid oxide fuel cell anode materials

    International Nuclear Information System (INIS)

    Recent experimental and theoretical findings suggest that high-temperature solid oxide fuel cells (SOFCs) often suffer from performance degradation due to coarsening of the metallic-phase particles within the anode. In this study, we explore the feasibility of improving the microstructural stability of SOFC anode materials by tuning the contact angle between the metallic phase and electrolyte particles. To this end, a continuum diffuse-interface model is employed to capture the coarsening behavior of the metallic phase and simulate a range of equilibrium contact angles. The evolution of performance-critical, microstructural features is presented for varying degrees of phase wettability. It is found that both the density of electrochemically active triple- phase regions and contiguity of the electron-conducting phase display undesirable minima near the contact angle of conventional SOFC materials. Our results suggest that tailoring the interfacial properties of the constituent phases could lead to a significant increase in the performance and lifetime of SOFCs

  12. Experimental Measurement of Relative Permeability Functions for Fuel Cell GDL Materials

    KAUST Repository

    Hussaini, Irfan

    2009-01-01

    Gas diffusion layer in PEM fuel cells plays a pivotal role in water management. Modeling of liquid water transport through the GDL relies on knowledge of relative permeability functions in the in-plane and through-plane directions. In the present work, air and water relative permeabilities are experimentally determined as functions of saturation for typical GDL materials such as Toray-060, -090, -120 carbon paper and E-Tek carbon cloth materials in their plain, untreated forms. Saturation is measured using an ex-situ gravimetric method. Absolute and relative permeability functions in the two directions of interest are presented. Significant departure from the generally assumed cubic function of saturation is observed. ©The Electrochemical Society.

  13. Performance Improvement of Bulk Heterojunction Organic Photovoltalc Cell by Addition of a Hole Transport Material

    Institute of Scientific and Technical Information of China (English)

    ZHANG Nan; LIU Qian; MAO Jie; LIU Zun-Feng; YANG Li-Ying; YIN Shou-Gen; CHEN Yong-Sheng

    2008-01-01

    @@ A novel photovoltaic cell with an active layer of poly(phenyleneethynylene)(PPE)/C60/N,N'-diphenyl-N,N'-di-(m-tolyl)-p-benzidine(TPD)is designed.In the active layer,PPE is the major component;C60 and TPD are the minor ones.Compared with a control BHJ device based on PPE/C60,the short circuit current density Jsc is increased by 1 order of magnitude,and the whole device performance is increased greatly,however the open circuit voltage Voc is largely decreased.The possible mechanism of the improved performance may be as follows:In the PPE/C60/TPD device,PPE,C60,and TPD serve as the energy harvesting material,the electron transport material,and the hole transport materiall respectively.As the TPD and C60 are spatially separated by PPE,the charge recombination is effectively retarded.

  14. Electrode materials: a challenge for the exploitation of protonic solid oxide fuel cells

    Directory of Open Access Journals (Sweden)

    Emiliana Fabbri, Daniele Pergolesi and Enrico Traversa

    2010-01-01

    Full Text Available High temperature proton conductor (HTPC oxides are attracting extensive attention as electrolyte materials alternative to oxygen-ion conductors for use in solid oxide fuel cells (SOFCs operating at intermediate temperatures (400–700 °C. The need to lower the operating temperature is dictated by cost reduction for SOFC pervasive use. The major stake for the deployment of this technology is the availability of electrodes able to limit polarization losses at the reduced operation temperature. This review aims to comprehensively describe the state-of-the-art anode and cathode materials that have so far been tested with HTPC oxide electrolytes, offering guidelines and possible strategies to speed up the development of protonic SOFCs.

  15. Investigation of test methods, material properties, and processes for solar-cell encapsulants. Annual report

    Energy Technology Data Exchange (ETDEWEB)

    Willis, P. B.; Baum, B.

    1982-07-01

    Potentially useful low cost encapsulation materials are evaluated. The goal of the program is to identify, evaluate, test, and recommend encapsulant materials and processes for the production of cost-effective, long life solar cell modules. Technical investigations have concerned the development of advanced cure chemistries for lamination type pottants, the continued evaluation of soil resistant surface treatments, and the results of an accelerated aging test program for the comparison of material stabilities. Experiments are underway to assess the durability and cost effectiveness of coatings for protection of steel. Investigations are continuing with commercial maintenance coatings based on fluorocarbon and silicone-alkyd chemistries. Experiments were conducted to determine the effectiveness of occlusive coatings for wood products such as hard-board. An experimental program continued to determine the usefulness of soil resistant coatings. Primers were evaluated for effectiveness in bonding candidate pottants to outer covers, glass and substate materials. A program of accelerated aging and life predictive strategies is being conducted and data are reported for sunlamp exposure and thermal aging. Supporting activities are also discussed briefly. (LEW)

  16. The Architecture of Colloidal Quantum Dot Solar Cells: Materials to Devices

    KAUST Repository

    Kramer, Illan J.

    2014-01-08

    The materials chemistry of Colloidal Quantum Dot (CQDs) suspended in solution and processed into films has provided a foundation onto which useful photovoltaic devices can be built. These active materials offer the benefits of solution processing paired with the flexibility of adjustable bandgaps, tailored to suit a particular need. In parallel with these advances, pursuing device geometries that better leverage the available electronic properties of CQD films has borne fruit in further advancing CQD solar cell performance. For active materials such as CQD films where 1/α, where alpha is the absorption coefficient, is of the same order as the free carrier extraction length, external quantum efficiency (EQE) measurements have proved useful in profiling the effectiveness of each nanometer of device thickness at extracting photogenerated carriers. Because CQD films have the added complications of being made of variable-sized constituent material building blocks as well as being deposited from solution, the nature of charge transport through the films can also be size-dependent and matrix dependent.

  17. Sorbent Material Property Requirements for On-Board Hydrogen Storage for Automotive Fuel Cell Systems.

    Energy Technology Data Exchange (ETDEWEB)

    Ahluwalia, R. K.; Peng, J-K; Hua, T. Q.

    2015-05-25

    Material properties required for on-board hydrogen storage in cryogenic sorbents for use with automotive polymer electrolyte membrane (PEM) fuel cell systems are discussed. Models are formulated for physical, thermodynamic and transport properties, and for the dynamics of H-2 refueling and discharge from a sorbent bed. A conceptual storage configuration with in-bed heat exchanger tubes, a Type-3 containment vessel, vacuum insulation and requisite balance-of-plant components is developed to determine the peak excess sorption capacity and differential enthalpy of adsorption for 5.5 wt% system gravimetric capacity and 55% well-to-tank (WTT) efficiency. The analysis also determines the bulk density to which the material must be compacted for the storage system to reach 40 g.L-1 volumetric capacity. Thermal transport properties and heat transfer enhancement methods are analyzed to estimate the material thermal conductivity needed to achieve 1.5 kg.min(-1) H-2 refueling rate. Operating temperatures and pressures are determined for 55% WTT efficiency and 95% usable H-2. Needs for further improvements in material properties are analyzed that would allow reduction of storage pressure to 50 bar from 100 bar, elevation of storage temperature to 175-200 K from 150 K, and increase of WTT efficiency to 57.5% or higher.

  18. Investigation of test methods, material properties, and processes for solar cell encapsulants. Annual report

    Energy Technology Data Exchange (ETDEWEB)

    Willis, P. B.; Baum, B.; Schnitzer, H. S.

    1980-07-01

    The goal of this program is to identify, evaluate, and recommend encapsulant materials and processes for the production of cost-effective, long-life solar cell modules. Technical activities during the past year have covered a number of topics and have emphasized the development of solar module encapsulation technology that employs ethylene/vinyl acetate, copolymer (EVA) as the pottant. These activities have included: (1) continued production of encapsulation grade EVA in sheet form to meet the needs of the photovoltaic industry; (2) investigations of three non-blocking techniques for EVA sheet; (3) performed an economic analysis of the high volume production of each pottant in order to estimate the large volume selling price (EVA, EPDM, aliphatic urethane, PVC plastisol, and butyl acrylate); (4) initiated an experimental corrosion protection program to determine if metal components could be successfully protected by encapsulation; (5) began an investigation to determine the maximum temperature which can be tolerated by the candidate pottant material in the event of hot spot heating or other temperature override; (6) continuation of surveys of potentially useful outer cover materials; and (7) continued with the accelerated artificial weathering of candidate encapsulation materials. Study results are presented. (WHK)

  19. Electrodeposition of CuIn1-xGaxSe2 Materials for Solar Cells:

    International Nuclear Information System (INIS)

    This report describes our scientific understanding of the CIGS materials system, solar cells, and processes. Through DOE support, the investigators developed much of the technology and device fabrication infrastructure applied to electrodeposited (ED) materials. The electrodeposition process is simple and fast, and can synthesize multinary precursors for subsequent processing into CuInxGa1-xSe2 (CIGS) thin-film absorbers for solar cells. The device fabricated by using electrodeposited CIGS precursor layers resulted in total-area conversion efficiencies up to 15.4%. As-deposited precursors are Cu-rich CIGS. Additional In, Ga, and Se (up to 50%) are added to the precursor films by physical vapor deposition (PVD) to adjust the final semiconductor film composition to about Cu0.95In0.75Ga0.25Se2. The ED device parameters are compared with those of an 18.8% PVD device. The tools used for comparison are current-voltage, capacitance-voltage, and spectral response characteristics. The individual parameters of the device prepared from ED precursor films showed no significant deterioration from those of the PVD CIGS cells. We also developed a buffer-based electrodeposition bath. Using the buffer solution enhances the stability of the electrodeposition process, and no metal oxides or hydroxides precipitate out of the solution. The buffer-based bath also deposits more gallium in the precursor films. As-deposited precursors are stoichiometric or slightly Cu-rich CIGS. Only a minimal amount (5%-10% of total materials) of indium was added to the ED precursor films by PVD to obtain a 9.4%-efficient device. In general, the films and devices have been characterized by inductively coupled plasma spectrometry, Auger electron spectroscopy, X-ray diffraction, electron-probe microanalysis, current-voltage, capacitance-voltage, and spectral response

  20. Carbon nanotube-based hybrid hole-transporting material and selective contact for high efficiency perovskite solar cells

    OpenAIRE

    Aitola, Kerttu; Sveinbjörnsson, Kári; Correa-Baena, Juan-Pablo; Kaskela, Antti; Abate, Antonio; Tian, Ying; Johansson, Erik M. J.; Graetzel, Michael; Kauppinen, Esko I.; Hagfeldt, Anders; Boschloo, Gerrit

    2016-01-01

    We demonstrate a high efficiency perovskite solar cell with a hybrid hole-transporting material-counter electrode based on a thin single-walled carbon nanotube (SWCNT) film and a drop-cast 2,2,7,-7-tetrakis(N, N-di-p-methoxyphenylamine)-9,90-spirobifluorene (Spiro-OMeTAD) hole-transporting material (HTM). The average efficiency of the solar cells was 13.6%, with the record cell yielding 15.5% efficiency. The efficiency of the reference solar cells with spin-coated Spiro-OMeTAD hole-transporti...

  1. [Studies on the cytotoxic action of various silicone rubber impression materials by means of cell culture (author's transl)].

    Science.gov (United States)

    Watanabe, H

    1977-07-01

    Biological test of the silicone rubber impression materials was done by utilizing tissue cultures of L strain cells. Criteria for cytotoxicity were based upon response index in agar diffusion method which was determined by zone index and lysis index, and morphological observations of the cells. The materials used were chosen among those which were commercially available. Base material, catalyst, unset and set mixes of both materials were tested respectively. X-ray fluorescence analysis of the material was also performed. Following results were obtained. 1) Base material of all the materials showed zone index of a range between 11.8 mm and 18.6 mm. On the otherhand, lysis index was relatively small and minimum response index was 11.8 mm/8.6 mm. The cells appeared normal after cultivation with the base materials, though tissue culture medium became opaque due to dissolution of the base materials. It is revealed that the above results mean little cytotoxicity to the cells. 2) Catalyst, on the otherhand, yielded intense cytotoxicity. Minimum response index for the catalyst was 13.4 mm/14.8 mm. Morphological observation was parallel to the results of agar diffusion method. 3) Unset mixes also yielded intense to moderate cytotoxicity. 4) Set mixes showed a similar in level of cytotoxicity to the unset mixes. 5) X-ray fluorescence analysis of the materials revealed existence of such elements as Si, Sr, Sn, S, Cu and Fe. Moreover, Zn was found in materials A, B, C, D and E; P in materials A and B, and Pb in materials E and F. However, it was unable to show what compound was formed by these elements. It is expected that the present results could give a clue on animal experiments or clinical use from the view point of biocompatibility of silicone rubber impression materials. PMID:282367

  2. Bipolar plate materials in molten carbonate fuel cells. Final CRADA report.

    Energy Technology Data Exchange (ETDEWEB)

    Krumpelt, M.

    2004-06-01

    Advantages of implementation of power plants based on electrochemical reactions are successfully demonstrated in the USA and Japan. One of the msot promising types of fuel cells (FC) is a type of high temperature fuel cells. At present, thanks to the efforts of the leading countries that develop fuel cell technologies power plants on the basis of molten carbonate fuel cells (MCFC) and solid oxide fuel cells (SOFC) are really close to commercialization. One of the problems that are to be solved for practical implementation of MCFC and SOFC is a problem of corrosion of metal components of stacks that are assembled of a number of fuel cells. One of the major components of MCFC and SOFC stacks is a bipolar separator plate (BSP) that performs several functions - it is separation of reactant gas flows sealing of the joints between fuel cells, and current collection from the surface of electrodes. The goal of Task 1 of the project is to develop new cost-effective nickel coatings for the Russian 20X23H18 steel for an MCFC bipolar separator plate using technological processes usually implemented to apply corrosion stable coatings onto the metal parts for products in the defense. There was planned the research on production of nickel coatings using different methods, first of all the galvanic one and the explosion cladding one. As a result of the works, 0.4 x 712 x 1296 mm plates coated with nickel on one side were to be made and passed to ANL. A line of 4 galvanic baths 600 liters was to be built for the galvanic coating applications. The goal of Task 2 of the project is the development of a new material of an MCFC bipolar separator plate with an upgraded corrosion stability, and development of a technology to produce cold roll sheets of this material the sizes of which will be 0.8 x 712x 1296 mm. As a result of these works, a pilot batch of the rolled material in sheets 0.8 x 712 x 1296 mm in size is to be made (in accordance with the norms and standards of the Russian

  3. Counting cells in sectioned material: a suite of techniques, tools, and tips.

    Science.gov (United States)

    Williams, Robert W; von Bartheld, Christopher S; Rosen, Glenn D

    2003-11-01

    This unit presents protocols to obtain accurate estimates of cell density and cell number in sectioned material by using a light microscope. The "optical disector" or "3-D counting method" is described, followed by Abercrombie's less commonly used two-section comparison (TSC) method. These basic protocols are accompanied by four support protocols: one for celloidin embedding, which renders superb morphology, one for point counting, which is important for volume measurements and is almost always used in conjunction with the disector or 3-D counting, one for handling the potential problem of z-axis distortion and the consequences that this error can have on density estimates and sampling tactics when using the disector, and finally, one that provides a guide for calibrating and verifying estimates obtained by counting methods. PMID:18428578

  4. Materials testing at the hot cell laboratory of the Institute for Safety Research

    International Nuclear Information System (INIS)

    The hot cell laboratories for handling and testing of irradiated specimens were firstly introduced in the annual report 1997. The following equipments are installed in the 'Shielded Containment' of the materials testing laboratory. Irradiated specimens must be tested and handled remotely, i.e. automatically by manipulators. Any direct action by hand is impossible as routine and only very restricted in case of uncommon events. Therefore, the handling, testing and measuring systems must work practicably, correctly and reliably. To prove this, a comprehensive test programme was accomplished before starting testing of irradiated specimens. In detail, the programme had to show that: - All systems work satisfactorily under the hot cell conditions, - the testing procedures fulfill the recommendations of the test specifications according to the standards, and - the results measured are accurate. (orig.)

  5. Hot carrier solar cell absorbers: investigation of carrier cooling properties of candidate materials

    Science.gov (United States)

    Conibeer, G.; Shrestha, Santosh; Huang, Shujuan; Patterson, Robert; Xia, Hongze; Feng, Yu; Zhang, Pengfei; Gupta, Neeti; Smyth, Suntrana; Liao, Yuanxun; Lin, Shu; Wang, Pei; Dai, Xi; Chung, Simon; Yang, Jianfeng; Zhang, Yi

    2015-09-01

    The hot carrier cell aims to extract the electrical energy from photo-generated carriers before they thermalize to the band edges. Hence it can potentially achieve a high current and a high voltage and hence very high efficiencies up to 65% under 1 sun and 86% under maximum concentration. To slow the rate of carrier thermalisation is very challenging, but modification of the phonon energies and the use of nanostructures are both promising ways to achieve some of the required slowing of carrier cooling. A number of materials and structures are being investigated with these properties and test structures are being fabricated. Initial measurements indicate slowed carrier cooling in III-Vs with large phonon band gaps and in multiple quantum wells. It is expected that soon proof of concept of hot carrier devices will pave the way for their development to fully functioning high efficiency solar cells.

  6. Benzotrithiophene-Based Hole-Transporting Materials for 18.2 % Perovskite Solar Cells.

    Science.gov (United States)

    Molina-Ontoria, Agustín; Zimmermann, Iwan; Garcia-Benito, Inés; Gratia, Paul; Roldán-Carmona, Cristina; Aghazada, Sadig; Graetzel, Michael; Nazeeruddin, Mohammad Khaja; Martín, Nazario

    2016-05-17

    New star-shaped benzotrithiophene (BTT)-based hole-transporting materials (HTM) BTT-1, BTT-2 and BTT-3 have been obtained through a facile synthetic route by crosslinking triarylamine-based donor groups with a benzotrithiophene (BTT) core. The BTT HTMs were tested on solution-processed lead trihalide perovskite-based solar cells. Power conversion efficiencies in the range of 16 % to 18.2 % were achieved under AM 1.5 sun with the three derivatives. These values are comparable to those obtained with today's most commonly used HTM spiro-OMeTAD, which point them out as promising candidates to be used as readily available and cost-effective alternatives in perovskite solar cells (PSCs). PMID:27061436

  7. Si nanoparticle interfaces in Si/SiO solar cell materials

    DEFF Research Database (Denmark)

    Kilpeläinen, S.; Kujala, J.; Tuomisto, F.;

    2013-01-01

    Novel solar cell materials consisting of Si nanoparticles embedded in SiO2 layers have been studied using positron annihilation spectroscopy in Doppler broadening mode and photoluminescence. Two positron-trapping interface states are observed after high temperature annealing at 1100 °C. One of the...... states is attributed to the (SiO2/Si bulk) interface and the other to the interface between the Si nanoparticles and SiO2. A small reduction in positron trapping into these states is observed after annealing the samples in N2 atmosphere with 5% H2. Enhanced photoluminescence is also observed from the...

  8. Charge transfer dynamics from organometal halide perovskite to polymeric hole transport materials in hybrid solar cells

    OpenAIRE

    Brauer, Jan C.; Lee, Yong Hui; Nazeeruddin, Mohammad Khaja; Banerji, Natalie

    2016-01-01

    Organometal halide perovskites have emerged as promising next-generation solar cell technologies presenting outstanding efficiencies. However, many questions concerning their working principles remain to be answered. Here, we present a detailed study of hole transfer dynamics into polymeric hole transporting materials (HTMs), poly(triarylamine) (PTAA), poly(3-hexylthiophee-2,5-diyl (P3HT), and poly[2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b′]dithiophene)-alt-4,7-(2,1,3-benzothiadiaz...

  9. Final Scientific Report, New Proton Conductive Composite Materials for PEM Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Lvov, Serguei

    2010-11-08

    This project covered one of the main challenges in present-day PEM fuel cell technology: to design a membrane capable of maintaining high conductivity and mechanical integrity when temperature is elevated and water vapor pressure is severely reduced. The DOE conductivity milestone of 0.1 S cm-1 at 120 degrees C and 50 % relative humidity (RH) for designed membranes addressed the target for the project. Our approach presumed to develop a composite membrane with hydrophilic proton-conductive inorganic material and the proton conductive polymeric matrix that is able to “bridge” the conduction paths in the membrane. The unique aspect of our approach was the use of highly functionalized inorganic additives to benefit from their water retention properties and high conductivity as well. A promising result turns out that highly hydrophilic phosphorsilicate gels added in Nafion matrix improved PEM fuel cell performance by over 50% compared with bare Nafion membrane at 120 degrees C and 50 % RH. This achievement realizes that the fuel cell operating pressure can be kept low, which would make the PEM fuel cell much more cost efficient and adaptable to practical operating conditions and facilitate its faster commercialization particularly in automotive and stationary applications.

  10. Alternative approaches of SiC & related wide bandgap materials in light emitting & solar cell applications

    Science.gov (United States)

    Wellmann, Peter; Syväjärvi, Mikael; Ou, Haiyan

    2014-03-01

    Materials for optoelectronics give a fascinating variety of issues to consider. Increasingly important are white light emitting diode (LED) and solar cell materials. Profound energy savings can be done by addressing new materials. White light emitting diodes are becoming common in our lighting scene. There is a great energy saving in the transition from the light bulb to white light emitting diodes via a transition of fluorescent light tubes. However, the white LEDs still suffer from a variety of challenges in order to be in our daily use. Therefore there is a great interest in alternative lighting solutions that could be part of our daily life. All materials create challenges in fabrication. Defects reduce the efficiency of optical transitions involved in the light emitting diode materials. The donor-acceptor co-doped SiC is a potential light converter for a novel monolithic all-semiconductor white LED. In spite of considerable research, the internal quantum efficiency is far less than theoretically predicted and is likely a fascinating scientific field for studying materials growth, defects and optical transitions. Still, efficient Si-based light source represents an ongoing research field in photonics that requires high efficiency at room temperature, wavelength tuning in a wide wavelength range, and easy integration in silicon photonic devices. In some of these devices, rare earth doped materials is considered as a potential way to provide luminescence spanning in a wide wavelength range. Divalent and trivalent oxidation states of Eu provide emitting centers in the visible region. In consideration, the use of Eu in photonics requires Eu doped thin films that are compatible with CMOS technology but for example faces material science issues like a low Eu solid solubility in silica. Therefore approaches aim to obtain efficient light emission from silicon oxycarbide which has a luminescence in the visible range and can be a host material for rare earth ions. The

  11. Characterization and modeling of InGaAs and InGaSb thermophotovoltaic cells and materials

    Energy Technology Data Exchange (ETDEWEB)

    Zierak, M.J. [Rensselaer Polytechnic Inst., Troy, NY (United States)

    1997-03-01

    Characterization of thermophotovoltaic (TPV) semiconductor materials before and after the fabrication of TPV cells is a very important part of obtaining good quality TPV converters. Various measurements setups have been designed and built to characterize both the starting material and finished TPV cells. These measurement setups include a microwave reflectance setup to obtain bulk lifetime data of starting material, a V{sub oc} decay setup to obtain lifetime data for finished cells, a quantum efficiency setup to measure the external quantum efficiency of finished cells, a capacitance-voltage setup to measure built-in potentials and base doping profiles of cells and a pulsed current-voltage setup to obtain the electrical characteristics of both illuminated and unilluminated TPV cells. A TPV cell simulation program was developed to help optimize the design of In{sub x}Ga{sub 1{minus}x}As and In{sub x}Ga{sub 1{minus}x}Sb cells operating at room temperature. The program is also capable of extracting diffusion lengths and surface recombination velocities from quantum efficiency measurements of finished cells. The program calculates not only the quantum efficiency of a cell, but also the illuminated current density vs. voltage for any incident spectrum. This allows the determination of the electrical characteristics and conversion efficiency of a cell prior to fabrication.

  12. Effects of Surface Morphology ZnAl2O4 of Ceramic Materials on Osteoblastic Cells Responses

    International Nuclear Information System (INIS)

    Ceramic scaffolds are widely studied in the tissue engineering field due to their potential in medical applications as bone substitutes or as bone-filling materials. The purpose of this study was to investigate the effect of surface morphology of nano structure thin films of ZnAl2O4 prepared by spray pyrolysis and bulk pellets of polycrystalline ZnAl2O4 prepared by chemical coprecipitation reaction on the in vitro cell adhesion, viability, and cell-material interactions of osteoblastic cells. Our result showed that cell attachment was significantly enhanced from 60 to 80% on the ZnAl2O4 nano structured material surface when compared with bulk ceramic surfaces. Moreover, our results showed that the balance of morphological properties of the thin film nano structure ceramic improves cell-material interaction with enhanced spreading and filopodia with multiple cellular extensions on the surface of the ceramic and enhancing cell viability/proliferation in comparison with bulk ceramic surfaces used as control. Altogether, these results suggest that zinc aluminate nano structured materials have a great potential to be used in dental implant and bone substitute applications.Ceramic scaffolds are widely studied in the tissue engineering field due to their potential in medical applications as bone substitutes or as bone-filling materials. The purpose of this study was to investigate the effect of surface morphology of nano structure thin films of ZnAl2O4 prepared by spray pyrolysis and bulk pellets of polycrystalline ZnAl2O4 prepared by chemical coprecipitation reaction on the in vitro cell adhesion, viability, and cell-material interactions of osteoblastic cells. Our result showed that cell attachment was significantly enhanced from 60 to 80% on the ZnAl2O4 nano structured material surface when compared with bulk ceramic surfaces. Moreover, our results showed that the balance of morphological properties of the thin film nano structure ceramic improves cell-material

  13. Solid state 1H NMR studies of cell wall materials of potatoes

    Science.gov (United States)

    Tang, Huiru; Belton, Peter S.; Ng, Annie; Waldron, Keith W.; Ryden, Peter

    1999-04-01

    Cell wall materials from potatoes ( Solanum tuberosum) prepared by two different methods have been studied using NMR proton relaxation times. Spin lattice relaxation in both the rotating and laboratory frames as well as transverse relaxation have been measured over a range of temperatures and hydration levels. It was observed that the sample prepared using a DMSO extraction showed anomalous behaviour of spin lattice relaxation in the laboratory frame probably due to residual solvent in the sample. Spin lattice relaxation in the laboratory frame is the result of hydroxymethyl rotation and another unidentified high frequency motion. In the rotating frame relaxation is adequately explained by hydroxymethyl rotation alone. In neither experiment is methyl group rotation observed, calculation suggests that this is due to the low density of methyl groups in the sample. Non-freezing water in potato cell walls, α-cellulose and pectin was found about 0.2, 0.04 and 0.18 g per gram dry matter, indicating preferable hydration of pectin compared to cellulose. The effects of hydration are most noticeable in the measurements that reflect low frequency motions, particularly transverse relaxation, where both second moments and the relative intensity of signals arising from immobile material are reduced by hydration.

  14. The new electron beam facility for materials testing in hot cells - design and preliminary experience

    International Nuclear Information System (INIS)

    Testing of materials which have been subjected to neutron irradiation will be carried out for the fusion reactor research programme at the KFA. An electron beam test apparatus Juelich Divertor Test Equipment in Hot Cells (JUDITH) has been installed in the Hot Cells of the Institute for Materials in Energy Systems, complementing the test equipment available in Japan, USA, France and RF [1-3]. Gamma ray emitting specimens are to be tested under thermal shock, thermal cycling and long-term loading conditions. The apparatus, built in cooperation with the PTR (Praezisionstechnik Remagen), consists of a electron beam unit with a beam power of 60 kW. The max. acceleration voltage is 150 kV, the max. beam current 400 mA. The beam can be deflected with a frequency of 100 kHz in x-y-direction with an amplitude of ±50 mm. Short pulses between 1 and 10 ms for the simulation of disruptions are possible, also longtime pulses on actively cooled samples. The samples are positioned in a vacuum chamber by remote handling. The sample holder is mounted on a cross-table, allowing the appropriate beam position for each specimen to be defined. A flange on the side of the chamber can be used for introducing an actively cooled divertor element. The cooling circuit has a flow rate of 5 m3/h and a pressure of 4 MPa, enabling a high thermal power to be used under continuous operation. (orig.)

  15. Effect of Doping Phosphorescent Material and Annealing Treatment on the Performance of Polymer Solar Cells

    Directory of Open Access Journals (Sweden)

    Zixuan Wang

    2013-01-01

    Full Text Available A series of polymer solar cells (PSCs with P3HT:PCBM or P3HT:PCBM:Ir(btpy3 blend films as the active layer were fabricated under the same conditions. Effects of phosphorescent material Ir(btpy3 doping concentration and annealing temperature on the performance of PSCs were investigated. The short-circuit current density (Jsc and open-circuit voltage (Voc are increased by adopting P3HT:PCBM:Ir(btpy3 blend films as the active layer when the cells do not undergo annealing treatment. The increased Jsc should be attributed to the increase of photon harvesting induced by doping phosphorescent material Ir(btpy3 and the effective energy transfer from Ir(btpy3 to P3HT. The effective energy transfer from Ir(btpy3 to P3HT was demonstrated by time-resolved photoluminescence (PL spectra. The increased Voc is due to the photovoltaic effect between Ir(btpy3 and PCBM. The power conversion efficiency (PCE of PSCs with P3HT:PCBM as the active layer is increased from 0.19% to 1.49% by annealing treatment at 140°C for 10 minutes. The PCE of PSCs with P3HT:PCBM:Ir(btpy3 as the active layer is increased from 0.49% to 0.95% by annealing treatment at lower temperature at 100°C for 10 minutes.

  16. Polymer:fullerene solar cells: materials, processing issues, and cell layouts to reach power conversion efficiency over 10%, a review

    Science.gov (United States)

    Etxebarria, Ikerne; Ajuria, Jon; Pacios, Roberto

    2015-01-01

    In spite of the impressive development achieved by organic photovoltaics throughout the last decades, especially in terms of reported power conversion efficiencies, there are still important technological and fundamental obstacles to circumvent before they can be implemented into reliable and long-lasting applications. Regarding device processing, the synthesis of highly soluble polymeric semiconductors first, and then fullerene derivatives, was initially considered as an important breakthrough that would definitely change the fabrication of photovoltaics once and for all. The potential and the expectation raised by this technology is such that it is very difficult to keep track of the most significant progresses being now published in different and even monographic journals. In this paper, we review the development of polymeric solar cells from its origin to the most efficient devices published to date. We separate these achievements into three different categories traditionally followed by the scientific community to push devices over 10% power conversion efficiency: active materials, strategies-fabrication/processing procedures-that can mainly modify the active film morphology, and all the different cell layout/architectures that have been used in order to extract as high a photocurrent as possible from the Sun. The synthesis of new donors, the use of additives and postprocessing techniques, buffer interlayers, inverted and tandem designs are some of the most important aspects that are reviewed in detail in this paper. All have equally contributed to develop this technology and bring it at the doors of commercialization.

  17. Metal Nanoparticles and Carbon-Based Nanostructures as Advanced Materials for Cathode Application in Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Pietro Calandra

    2010-01-01

    Full Text Available We review the most advanced methods for the fabrication of cathodes for dye-sensitized solar cells employing nanostructured materials. The attention is focused on metal nanoparticles and nanostructured carbon, among which nanotubes and graphene, whose good catalytic properties make them ideal for the development of counter electrode substrates, transparent conducting oxide, and advanced catalyst materials.

  18. Methods for using novel cathode and electrolyte materials for solid oxide fuel cells and ion transport membranes

    Science.gov (United States)

    Jacobson, Allan J.; Wang, Shuangyan; Kim, Gun Tae

    2016-01-12

    Methods using novel cathode, electrolyte and oxygen separation materials operating at intermediate temperatures for use in solid oxide fuel cells and ion transport membranes include oxides with perovskite related structures and an ordered arrangement of A site cations. The materials have significantly faster oxygen kinetics than in corresponding disordered perovskites.

  19. Scientific Assessment in support of the Materials Roadmap enabling Low Carbon Energy Technologies: Hydrogen and Fuel Cells

    DEFF Research Database (Denmark)

    Cerri, I.; Lefebvre-Joud, F.; Holtappels, Peter;

    A group of experts from European research organisations and industry have assessed the state of the art and future needs for materials' R&D for hydrogen and fuel cell technologies. The work was performed as input to the European Commission's roadmapping exercise on materials for the European...

  20. Energy storage in hybrid organic-inorganic materials hexacyanoferrate-doped polypyrrole as cathode in reversible lithium cells

    DEFF Research Database (Denmark)

    Torres-Gomez, G,; Skaarup, Steen; West, Keld;

    2000-01-01

    A study of the hybrid oganic-inorganic hexacyanoferrate-polypyrrole material as a cathode in rechargeable lithium cells is reported as part of a series of functional hybrid materials that represent a new concept in energy storage. The effect of synthesis temperatures of the hybrid in the specific...

  1. Perovskites for energy applications. From cathode material for fuel cells to a gas separation membrane

    Energy Technology Data Exchange (ETDEWEB)

    Meulenberg, W.A.; Baumann, S.; Betz, M.; Buchkremer, H.P.; Stoever, D. [Forschungszentrum Juelich GmbH (DE). Inst. fuer Energieforschung (IEF); Serra, J.M.; Vert, V.B. [Universidad Politecnica de Valencia (Spain). Inst. de Tecnologia Quimica

    2010-07-01

    Oxyfuel power plants are one possibility for Carbon Capture and Storage (CCS) using pure oxygen instead of air to combust a carbon containing fuel. This oxygen can be produced by ceramic membranes, which consist of a Mixed Ionic Electronic Conductor (MIEC). Appropriate materials for oxygen separation from air are perovskites transporting oxygen ions through oxygen vacancies in the crystal lattice. Perovskites show highest permeability in particular Ba{sub 0.5}Sr{sub 0.5}Co{sub 0.8}Fe{sub 0.2}O{sub 3-{delta}} (BSCF) and offer a theoretical selectivity of 100%. However, perovskites with high permeability show in principle poor chemical stability e.g. in atmosphere containing CO{sub 2}, SO{sub 2}, or H{sub 2}O and particularly reducing conditions. Moreover the thermal and chemical expansion coefficient is very high, which makes the manufacturing of a gas-tight thin film on or joining to a material different from BSCF nearly impossible. Solid oxide fuel cells (SOFCs) are becoming promising candidates for highly efficient energy generation from conventional and biomass-derived fuels due to different reasons: (i) electricity can be obtained directly from a fuel; (ii) the sub-product is a high quality heat, usable in (micro) turbines and for building central heating (CHP) units; (iii) zero-emission operation is achieved when hydrogen is fuelled; (iv) SOFCs can operate besides H{sub 2} with hydrocarbons without extensive fuel purification and reforming; and (v) SOFCs are noiseless and modular. However, conventional SOFCs need to operate in the 800-1000 C temperature range. The reduction of the operating temperature below 700 C implies that the electrode polarization resistance of classical cathodes limits the whole cell operation, and consequently the performance is significantly reduced. Therefore, it is needed the development of new cathode materials with sufficient chemical stability and electrochemical activity to enable the operation at lower temperatures with

  2. Atomically thin two-dimensional materials as hole extraction layers in organolead halide perovskite photovoltaic cells

    Science.gov (United States)

    Kim, Yu Geun; Kwon, Ki Chang; Le, Quyet Van; Hong, Kootak; Jang, Ho Won; Kim, Soo Young

    2016-07-01

    Atomically thin two-dimensional materials such as MoS2, WS2, and graphene oxide (GO) are used as hole extraction layers (HEL) in organolead halide perovskites solar cells (PSCs) instead of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) HEL. MoS2 and WS2 layers with a polycrystalline structure were synthesized by a chemical deposition method using a uniformly spin-coated (NH4)MoS4 and (NH4)WS4 precursor solution. GO was synthesized by the oxidation of natural graphite powder using Hummers' method. The work functions of MoS2, WS2, and GO are measured to be 5.0, 4.95, and 5.1 eV, respectively. The X-ray diffraction spectrum indicated that the synthesized perovskite material is CH3NH3PbI3-xClx. The PSCs with the p-n junction structure were fabricated based on the CH3NH3PbI3-xClx perovskite layer. The power conversion efficiencies of the MoS2, WS2, and GO-based PSCs were 9.53%, 8.02%, and 9.62%, respectively, which are comparable to those obtained from PEDOT:PSS-based devices (9.93%). These results suggest that two-dimensional materials such as MoS2, WS2, and GO can be promising candidates for the formation of HELs in the PSCs.

  3. A molecularly engineered hole-transporting material for efficient perovskite solar cells

    Science.gov (United States)

    Saliba, Michael; Orlandi, Simonetta; Matsui, Taisuke; Aghazada, Sadig; Cavazzini, Marco; Correa-Baena, Juan-Pablo; Gao, Peng; Scopelliti, Rosario; Mosconi, Edoardo; Dahmen, Klaus-Hermann; de Angelis, Filippo; Abate, Antonio; Hagfeldt, Anders; Pozzi, Gianluca; Graetzel, Michael; Nazeeruddin, Mohammad Khaja

    2016-02-01

    Solution-processable perovskite solar cells have recently achieved certified power conversion efficiencies of over 20%, challenging the long-standing perception that high efficiencies must come at high costs. One major bottleneck for increasing the efficiency even further is the lack of suitable hole-transporting materials, which extract positive charges from the active light absorber and transmit them to the electrode. In this work, we present a molecularly engineered hole-transport material with a simple dissymmetric fluorene-dithiophene (FDT) core substituted by N,N-di-p-methoxyphenylamine donor groups, which can be easily modified, providing the blueprint for a family of potentially low-cost hole-transport materials. We use FDT on state-of-the-art devices and achieve power conversion efficiencies of 20.2% which compare favourably with control devices with 2,2‧,7,7‧-tetrakis(N,N-di-p-methoxyphenylamine)-9,9‧-spirobifluorene (spiro-OMeTAD). Thus, this new hole transporter has the potential to replace spiro-OMeTAD.

  4. Material research on amorphous silicon based alloys: Application to low-cost efficient solar cells

    International Nuclear Information System (INIS)

    Amorphous silicon solar cell technology has reached a high level of maturity, which is the result of several years of basic research and of an unprecedented industrial effort. It already occupies an unchallenged position for micro-power and indoor applications like light-powered calculators, watches, etc. With the presently available material, the technological improvements have practically reached their limits and little can be gained on the open voltage or the fill factor. The only substantial improvement to be expected is an increase in the short-circuit current by a better matching of the optical gap to the solar spectrum. In principle, one could almost double the short-circuit current by a moderate decrease of the optical gap from 1.8 eV to 1.4 eV. Unfortunately, the proper small-gap material, having good photovoltaic properties, still remains to be found and this is the subject of material research activities in many laboratories in the world. 17 refs, 4 figs

  5. Hole-transport material variation in fully vacuum deposited perovskite solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Polander, Lauren E.; Pahner, Paul; Schwarze, Martin; Saalfrank, Matthias; Koerner, Christian; Leo, Karl, E-mail: karl.leo@iapp.de [Institut für Angewandte Photophysik, Technische Universität Dresden, 01069 Dresden (Germany)

    2014-08-01

    This work addresses the effect of energy level alignment between the hole-transporting material and the active layer in vacuum deposited, planar-heterojunction CH{sub 3}NH{sub 3}PbI{sub x−3}Cl{sub x} perovskite solar cells. Through a series of hole-transport materials, with conductivity values set using controlled p-doping of the layer, we correlate their ionization potentials with the open-circuit voltage of the device. With ionization potentials beyond 5.3 eV, a substantial decrease in both current density and voltage is observed, which highlights the delicate energetic balance between driving force for hole-extraction and maximizing the photovoltage. In contrast, when an optimal ionization potential match is found, the open-circuit voltage can be maximized, leading to power conversion efficiencies of up to 10.9%. These values are obtained with hole-transport materials that differ from the commonly used Spiro-MeO-TAD and correspond to a 40% performance increase versus this reference.

  6. Hole-transport material variation in fully vacuum deposited perovskite solar cells

    International Nuclear Information System (INIS)

    This work addresses the effect of energy level alignment between the hole-transporting material and the active layer in vacuum deposited, planar-heterojunction CH3NH3PbIx−3Clx perovskite solar cells. Through a series of hole-transport materials, with conductivity values set using controlled p-doping of the layer, we correlate their ionization potentials with the open-circuit voltage of the device. With ionization potentials beyond 5.3 eV, a substantial decrease in both current density and voltage is observed, which highlights the delicate energetic balance between driving force for hole-extraction and maximizing the photovoltage. In contrast, when an optimal ionization potential match is found, the open-circuit voltage can be maximized, leading to power conversion efficiencies of up to 10.9%. These values are obtained with hole-transport materials that differ from the commonly used Spiro-MeO-TAD and correspond to a 40% performance increase versus this reference

  7. Rational Design of Diketopyrrolopyrrole-Based Small Moleculesas Donating Materials for Organic Solar Cells

    Directory of Open Access Journals (Sweden)

    Ruifa Jin

    2015-08-01

    Full Text Available A series of diketopyrrolopyrrole-based small molecules have been designed toexplore their optical, electronic, and charge transport properties as organic solar cell(OSCs materials. The calculation results showed that the designed molecules can lowerthe band gap and extend the absorption spectrum towards longer wavelengths.The designed molecules own the large longest wavelength of absorption spectra,the oscillator strength, and absorption region values. The optical, electronic, and chargetransport properties of the designed molecules are affected by the introduction of differentπ-bridges and end groups. We have also predicted the mobility of the designed moleculewith the lowest total energies. Our results reveal that the designed molecules are expectedto be promising candidates for OSC materials. Additionally, the designed molecules areexpected to be promising candidates for electron and/or hole transport materials. On thebasis of our results, we suggest that molecules under investigation are suitable donors for[6,6]-phenyl-C61-butyric acid methyl ester (PCBM and its derivatives as acceptors of OSCs.

  8. Hole-transport material variation in fully vacuum deposited perovskite solar cells

    Directory of Open Access Journals (Sweden)

    Lauren E. Polander

    2014-08-01

    Full Text Available This work addresses the effect of energy level alignment between the hole-transporting material and the active layer in vacuum deposited, planar-heterojunction CH3NH3PbIx−3Clx perovskite solar cells. Through a series of hole-transport materials, with conductivity values set using controlled p-doping of the layer, we correlate their ionization potentials with the open-circuit voltage of the device. With ionization potentials beyond 5.3 eV, a substantial decrease in both current density and voltage is observed, which highlights the delicate energetic balance between driving force for hole-extraction and maximizing the photovoltage. In contrast, when an optimal ionization potential match is found, the open-circuit voltage can be maximized, leading to power conversion efficiencies of up to 10.9%. These values are obtained with hole-transport materials that differ from the commonly used Spiro-MeO-TAD and correspond to a 40% performance increase versus this reference.

  9. Materials on the International Space Station-forward technology solar cell experiment

    International Nuclear Information System (INIS)

    This paper describes the forward technology solar cell experiment (FTSCE), which is a space experiment built by the Naval Research Laboratory (NRL) in collaboration with NASA Glenn Research Center (GRC), and the US Naval Academy (USNA) as part of the materials on the International Space Station (MISSE) program. The goal is to rapidly put current and future generation space solar cells on orbit and provide validation data for these technologies. Telemetry, command, control, and communication (TNC) for the FTSCE will be achieved through the Amateur Satellite Service using the PCSat2 system, which is an Amateur Radio system designed and built by the USNA. In addition to providing an off-the-shelf solution for FTSCE TNC, PCSat2 will provide a communications node for the Amateur Radio satellite system. The FTSCE and PCSat2 will be housed within the passive experiment container (PEC), which is an approximately 2 ft x 2 ft x 4 in. metal container built by NASA Langley Research Center (NASA LaRC) as part of the MISSE program. NASA LaRC has also supplied a thin film materials experiment that will fly on the exterior of the thermal blanket covering the PCSat2. The PEC is planned to be transported to the ISS on a Shuttle flight. The PEC will be mounted on the exterior of the ISS by an astronaut during an extravehicular activity (EVA). After nominally 1 year, the PEC will be retrieved and returned to Earth. This paper presents the design of the experiment, the electrical data measured on the experiment solar cells, and the results of environmental testing of the system

  10. The use of ultrasound for the fabrication of fuel cell materials

    Energy Technology Data Exchange (ETDEWEB)

    Pollet, Bruno G. [PEM Fuel Cell Research Group, Centre for Hydrogen and Fuel Cell Research, College of Engineering and Physical Sciences, The University of Birmingham, Edgbaston Road, Birmingham, B15 2TT (United Kingdom)

    2010-11-15

    This paper reviews the use and advantages of ultrasound for the preparation of fuel cell materials which is currently an emerging research area. The review also focuses on recent studies of ultrasonic, sonochemical and sonoelectrochemical production of noble metals and fuel cell electrocatalysts, carbon supported electrocatalysts, fuel cell electrodes and membranes. It is shown that ultrasound can be used as an effective method for producing nanosize mono- and bi-metallics (<10 nm) in the absence and presence of surfactants and alcohols. In most cases, the formation of nano-metallics is attributed to radical species (H. and OH.) generated by water sonolysis induced by cavitation whereby the nano-metallic size strongly depends upon the ultrasonic frequency and time, the type of surfactant, alcohol and atmospheric gas. It is also shown that the sonochemical production of carbon-supported mono- and bi-metallic catalysts gives excellent electrochemical activity due to surface functionalisation of the support and better dispersion induced by ultrasound. These observations are mainly due to enhanced mass-transfer caused by asymmetrical collapse of cavitation bubbles at the surface support leading to the formation of high velocity jets of liquid being directed toward its surface. This jetting, together with acoustic streaming, is thought to lead to random punctuation and disruption of the mass-transfer at the surface. (author)

  11. Tough and elastic hydrogel of hyaluronic acid and chondroitin sulfate as potential cell scaffold materials.

    Science.gov (United States)

    Ni, Yilu; Tang, Zhurong; Cao, Wanxu; Lin, Hai; Fan, Yujiang; Guo, Likun; Zhang, Xingdong

    2015-03-01

    Natural polysaccharides are extensively investigated as cell scaffold materials for cellular adhesion, proliferation, and differentiation due to their excellent biocompatibility, biodegradability, and biofunctions. However, their application is often severely limited by their mechanical behavior. In this study, a tough and elastic hydrogel scaffold was prepared with hyaluronic acid (HA) and chondroitin sulfate (CS). HA and CS were conjugated with tyramine (TA) and the degree of substitution (DS) was 10.7% and 11.3%, respectively, as calculated by (1)H NMR spectra. The hydrogel was prepared by mixing HA-TA and CS-TA in presence of H2O2 and HRP. The sectional morphology of hydrogels was observed by SEM, static and dynamic mechanical properties were analyzed by Shimadzu electromechanical testing machine and dynamic mechanical thermal analyzer Q800. All samples showed good ability to recover their appearances after deformation, the storage modulus (E') of hydrogels became higher as the testing frequency went up. Hydrogels also showed fatigue resistance to cyclic compression. Mesenchymal stem cells encapsulated in hydrogels showed good cell viability as detected by CLSM. This study suggests that the hydrogels have both good mechanical properties and biocompatibility, and may serve as model systems to explore mechanisms of deformation and energy dissipation or find some applications in tissue engineering. PMID:25445680

  12. Inhibitory Effects of Far-Infrared Irradiation Generated by Ceramic Material on Murine Melanoma Cell Growth

    Directory of Open Access Journals (Sweden)

    Ting-Kai Leung

    2012-01-01

    Full Text Available The biological effects of specific wavelengths, so-called “far-infrared radiation” produced from ceramic material (cFIR, on whole organisms are not yet well understood. In this study, we investigated the biological effects of cFIR on murine melanoma cells (B16-F10 at body temperature. cFIR irradiation treatment for 48 h resulted in an 11.8% decrease in the proliferation of melanoma cells relative to the control. Meanwhile, incubation of cells with cFIR for 48 h significantly resulted in 56.9% and 15.7% decreases in the intracellular heat shock protein (HSP70 and intracellular nitric oxide (iNO contents, respectively. Furthermore, cFIR treatment induced 6.4% and 12.3% increases in intracellular reactive oxygen species stained by 5-(and 6-carboxyl-2′,7′-dichlorodihydrofluorescein diacetate and dihydrorhodamine 123, respectively. Since malignant melanomas are known to have high HSP70 expression and iNO activity, the suppressive effects of cFIR on HSP70 and NO may warrant future interest in antitumor applications.

  13. Loss mechanisms in high-efficiency solar cells: Study of material properties and high-efficiency solar-cell performance on material composition: Project tasks

    Science.gov (United States)

    Sah, C. T.

    1985-01-01

    Loss mechanisms in high-efficiency solar cells were discussed. Fundamental limitations and practical solutions were stressed. Present cell efficiency is limited by many recombination sites: emitter, base, contacts, and oxide/silicon interface. Use of polysilicon passivation was suggested. After reduction of these losses, a 25% efficient cell could be built. A floating emitter cell design was shown that had the potential of low recombination losses.

  14. Scanning tunneling spectroscopy on the chalcopyrite solar cell absorber material Cu(In,Ga)Se{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Moenig, Harry; Saez-Araoz, Rodrigo; Lux-Steiner, Martha [Freie Universitaet Berlin (Germany); Sadewasser, Sascha; Ennaoui, Ahmed; Kaufmann, Christian; Kropp, Timo; Lauermann, Iver; Muenchenberg, Tim; Schock, Hans-Werner; Streicher, Ferdinand [Hahn- Meitner-Institut Berlin (Germany)

    2007-07-01

    Cu(In,Ga)Se{sub 2}-based thin film solar cells have reached efficiencies close to 20%. Nevertheless, little is known about electronic transport and carrier recombination in this material on a microscopic scale. Especially grain boundaries in these polycrystalline materials are considered to play an important role in the performance of these solar cells. We applied scanning tunneling microscopy and spectroscopy to gain more insight in the electronic microstructure of the material. Our results point to lateral electronic inhomogeneities on the absorber surface and to an enhanced density of states at grain boundaries. The influence of charging effects is discussed.

  15. The use of substrate materials and topography to modify growth patterns and rates of differentiation of muscle cells.

    Science.gov (United States)

    Murray, L M; Nock, V; Evans, J J; Alkaisi, M M

    2016-07-01

    Cells are cultured on platforms made of a variety of materials with selected topographies during studies of cell response and behavior. Understanding the effects of substrates is essential for such applications as developing effective interfaces between body cells and implanted materials and devices. In this study, the effects of substrate surface properties on cell differentiation and alignment on C2C12 myoblasts cultured on conventional or fabricated polymeric cell culture substrates were investigated. Comparisons were made between cells cultured on tissue culture grade polystyrene (TCPS), glass, Permanox, and cured polydimethylsiloxane (PDMS) substrates. Fluorescent immunohistochemistry of cell markers was used to analyse the extent of differentiation. Alignment and guidance of cell growth and spread were studied using patterned platforms. Gratings were made on polystyrene (PS) and PDMS and differentiation was facilitated after 5 days by media exchange. Differences in cell morphology were observed between cells cultured on TCPS and PDMS substrates. Fully differentiated myotubes were observed in highest numbers on TCPS substrates and were non-detectable on PDMS substrates in the time frame of 144 h. Muscle cell alignment and their differentiation followed along the grating patterns on PS and elongated along the pattern length. On the other hand, on PDMS cells formed sheets of tissue and peeled from the substrate. We have revealed the potential for the combinations of surface materials and topography on cell behavior to induce accelerated differentiation and coordinated alignment. The results demonstrate that culture environment can be designed or engineered to modify or regulate muscle cell functions. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1638-1645, 2016. PMID:26916910

  16. Interfacial electron transfer and bioelectrocatalysis of carbonized plant material as effective anode of microbial fuel cell

    International Nuclear Information System (INIS)

    ABSTRACT: Effective use of natural materials to fabricate porous carbonaceous structures for anodes of microbial fuel cells (MFCs) has a high potential for substantial cost reduction in MFC. In this study, three kinds of plant materials, i.e. king mushroom, wild mushroom and corn stem, were investigated for fabrication of conductive electrode materials by simple carbonization procedures. Structure–reactivity relationships of these electrodes were systematically studied with electrochemical redox probe ([Fe(CN)6]3−/4−) and biofilm electroactivity. The electrochemical and bioelectrochemical accessibilities of the carbonized electrodes were evaluated by impedance, cyclic voltammetry and chronoamperometry techniques in order to study the electron transfer rate (Kapp), charge transfer resistances, oxidative current density and bioelectroactive moieties. The results showed that the electron transfer resistance (Rct) was 94 Ω for carbonized corn stem electrode with an electron transfer rate (Kapp) of 3.44 × 10−2 cm s−1 for Fe2+/Fe3+ redox probe. Higher bioelectroactivity (9.29 × 10−8 mol cm−2) was found from biofilm on carbonized corn stem (Rbiofilm, 45 Ω) with an electron transfer rate (bacteria-anode) of 63 × 10−5 cm s−1. The maximum bioelectrocatalytic current (imax) of 3.12 mA cm−2 was obtained on carbon electrode derived from corn stem. That is 8 times higher than plain graphite electrode. The porous architecture, high electron transfer rate and high electroactive biofilm growth are attributes that qualify natural-material carbon anodes as low-cost alternative for MFC

  17. Functionalisation of mesoporous materials for application as additives in high temperature PEM fuel cell membranes

    Energy Technology Data Exchange (ETDEWEB)

    Sharifi, Monir

    2012-03-06

    The presented thesis contains six original research articles dedicated to the preparation and characterization of organic-inorganic mesoporous materials as additives for polymer electroly1e membrane fuel cells (PEMFCs). The mesoporous materials Si-MCM-41 and benzene-PMO (periodic mesoporous organosilica) were chosen for the investigations. These materials were modified with functional groups for enhanced proton conductivity and water-keeping properties. In order to improve these materials Broenstedt acidic groups were introduced in the framework of mesoporous Si-MCM-41. Therefore, some silicium atoms in the framework were substituted by aluminium using different aluminium sources. Here NaAlO{sub 2} exhibits clearly the best results because the entire aluminium incorporated within the framework is tetragonally coordinated as observed by {sup 2}7AI MAS NMR. The increase of the proton conductivities results from an improved hydrophilicity, a decreased particle size, and newly introduced Broenstedt acidity in the mesoporous Al-MCM-41. However, mesoporous Si-MCM-41 materials functionalised by co-condensation with sulphonic acid groups exhibit the best results concerning proton conductivity, compared to those prepared by grafting. Hence, these materials where characterized in more detail by SANS and by MAS NMR measurements. The first one indicated that by co-condensation the entire inner pore surface is altered by functional groups which are, thus, distributed much more homogeneously than samples functionalised by grafting. This result explains the improved proton conductivities. Additionally, {sup 2}9Si NMR spectra proved that samples prepared by co-condensation lead to a successful and almost complete incorporation of mercaptopropyltrimethoxysilan (MPMS) into the mesoporous framework. Furthermore, it was shown by {sup 1}3C MAS NMR spectroscopy that the majority of the organic functional groups remained intact after H{sub 2}0{sub 2}-oxidation. However, proton

  18. Chemical degradation of five elastomeric seal materials in a simulated and an accelerated PEM fuel cell environment

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chih-Wei [Department of Mechanical and Electro-Mechanical Engineering, National Sun Yat-Sen University, Kaohsiung 804 (China); Department of Mechanical Engineering, University of South Carolina, Columbia, SC 29208 (United States); Chien, Chi-Hui [Department of Mechanical and Electro-Mechanical Engineering, National Sun Yat-Sen University, Kaohsiung 804 (China); Tan, Jinzhu [College of Mechanical and Power Engineering, Nanjing University of Technology, Nanjing, Jiangsu 210009 (China); Chao, Yuh J. [Department of Mechanical Engineering, University of South Carolina, Columbia, SC 29208 (United States); Van Zee, J.W. [Department of Chemical Engineering, University of South Carolina, Columbia, SC 29208 (United States)

    2011-02-15

    Polymer electrolyte membrane (PEM) fuel cell stack requires gaskets and seals in each cell to keep the hydrogen and air/oxygen within their respective regions. The stability of the gaskets/seals is critical to the operating life as well as the electrochemical performance of the fuel cell. Chemical degradation of five elastomeric gasket materials in a simulated and an aggressive accelerated fuel cell solution at PEM operating temperature for up to 63 weeks was investigated in this work. The five materials are copolymeric resin (CR), liquid silicone rubber (LSR), fluorosilicone rubber (FSR), ethylene propylene diene monomer rubber (EPDM), and fluoroelastomer copolymer (FKM). Using optical microscopy, topographical changes on the sample surface due to the acidic environment were revealed. Weight loss of the test samples was monitored. Atomic absorption spectrometer analysis was performed to study the silicon, calcium, and magnesium leachants from the materials into the soaking solution. Attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy was employed to study the surface chemistry of the materials before and after exposure to the simulated fuel cell environment over time. Among the five materials studied, CR and LSR in the accelerated solution are not as stable as the other three materials. FSR appears to be the most stable. (author)

  19. Evaluation of critical materials for five advanced design photovoltaic cells with an assessment of indium and gallium

    Energy Technology Data Exchange (ETDEWEB)

    Watts, R.L.; Gurwell, W.E.; Jamieson, W.M.; Long, L.W.; Pawlewicz, W.T.; Smith, S.A.; Teeter, R.R.

    1980-05-01

    The objective of this study is to identify potential material supply constraints due to the large-scale deployment of five advanced photovoltaic (PV) cell designs, and to suggest strategies to reduce the impacts of these production capacity limitations and potential future material shortages. This report presents the results of the screening of the five following advanced PV cell designs: polycrystalline silicon, amorphous silicon, cadmium sulfide/copper sulfide frontwall, polycrystalline gallium arsenide MIS, and advanced concentrator-500X. Each of these five cells is screened individually assuming that they first come online in 1991, and that 25 GWe of peak capacity is online by the year 2000. A second computer screening assumes that each cell first comes online in 1991 and that each cell has 5 GWe of peak capacity by the year 2000, so that the total online cpacity for the five cells is 25 GWe. Based on a review of the preliminary basline screening results, suggestions were made for varying such parameters as the layer thickness, cell production processes, etc. The resulting PV cell characterizations were then screened again by the CMAP computer code. Earlier DOE sponsored work on the assessment of critical materials in PV cells conclusively identtified indium and gallium as warranting further investigation as to their availability. Therefore, this report includes a discussion of the future availability of gallium and indium. (WHK)

  20. Prevalence of human cell material: DNA and RNA profiling of public and private objects and after activity scenarios.

    Science.gov (United States)

    van den Berge, M; Ozcanhan, G; Zijlstra, S; Lindenbergh, A; Sijen, T

    2016-03-01

    Especially when minute evidentiary traces are analysed, background cell material unrelated to the crime may contribute to detectable levels in the genetic analyses. To gain understanding on the composition of human cell material residing on surfaces contributing to background traces, we performed DNA and mRNA profiling on samplings of various items. Samples were selected by considering events contributing to cell material deposits in exemplary activities (e.g. dragging a person by the trouser ankles), and can be grouped as public objects, private samples, transfer-related samples and washing machine experiments. Results show that high DNA yields do not necessarily relate to an increased number of contributors or to the detection of other cell types than skin. Background cellular material may be found on any type of public or private item. When a major contributor can be deduced in DNA profiles from private items, this can be a different person than the owner of the item. Also when a specific activity is performed and the areas of physical contact are analysed, the "perpetrator" does not necessarily represent the major contributor in the STR profile. Washing machine experiments show that transfer and persistence during laundry is limited for DNA and cell type dependent for RNA. Skin conditions such as the presence of sebum or sweat can promote DNA transfer. Results of this study, which encompasses 549 samples, increase our understanding regarding the prevalence of human cell material in background and activity scenarios. PMID:26736139

  1. Karakterisasi Dan Analisa Kadar Nutrisi Edible Film Dari Nata De Coco Dengan Penambahan Pati, Gliserin, Dan Kitosan Sebagai Bahan Pengemas Makanan

    OpenAIRE

    Biamenta, Egyfaldi

    2011-01-01

    The research about characterization and analysis nutrient content of edible film from nata de coco with adding starch, chitosan, and glycerin that will be applied as food coating material. The analyzed parameter was thick of edible film, Scanning Electron Microscope (SEM), tensile strength, elasticity, water contents, ash contents, protein contents, lipid contents, carbohydrate contents, and fiber contents. The water contents was determined by thermogravimetric method, the ash contents was de...

  2. Karakterisasi Simplisia dan Uji Aktivitas Antioksidan Ekstrak n-Heksan, Etil Asetat dan Etanol Daun Muda Dari Labu Siam (Sechium edule (Jacq.) Sw.) Dengan Metode DPPH

    OpenAIRE

    Febrita, Diana

    2011-01-01

    Honey is viscous liquid was collected in honey ovarian by bee. Honey contain of organic acid, enzyme, fenolic acid, flavonoid, beta caroten, Vitamin A, C and E. Honey contain many nutrision that use as antioxidant and all of that cooperate to save the normal cell from free radicals. It has been done characterization an antioxidant activity test of honey from Lhoknga, Montasik and Sare forest. Antioxidant activity determined by damping of 1.1-diphenyl-2-picrylhydrazyl (DPPH) according to spect...

  3. Karakterisasi dan Skrining Fitokimia serta Uji Aktivitas Antioksidan Ekstrak Etanol dan Jus Daging Buah Salak (Salacca Sumatrana Becc) dengan Metode DPPH

    OpenAIRE

    Novriani, Erida

    2014-01-01

    Antioxidant can neutralize the free radical formation, one of substances cause cell or tissue damage. Salak flesh contain chemicals that have the potential as an antioxidant that can neutralize free radicals. The purpose of this study was to obserb simplex characterization, phytochemical screening, and the antioxidant activity of salak flesh ethanol extracts and juice. Salak ethanol extract can be obtained by maceration with ethanol 96%. Subsequently , the extract was concentrated using a ...

  4. Electrodeposited gold nanoparticles on carbon nanotube-textile: Anode material for glucose alkaline fuel cells

    KAUST Repository

    Pasta, Mauro

    2012-06-01

    In the present paper we propose a new anode material for glucose-gluconate direct oxidation fuel cells prepared by electrodepositing gold nanoparticles onto a conductive textile made by conformally coating single walled carbon nanotubes (SWNT) on a polyester textile substrate. The electrodeposition conditions were optimized in order to achieve a uniform distribution of gold nanoparticles in the 3D porous structure of the textile. On the basis of previously reported studies, the reaction conditions (pH, electrolyte composition and glucose concentration) were tuned in order to achieve the highest oxidation rate, selectively oxidizing glucose to gluconate. The electrochemical characterization was carried out by means of cyclic voltammetry. © 2012 Elsevier B.V. All rights reserved.

  5. Mould Design and Material selection for Film Insert Moulding of Direct Methanol Fuel Cell Packaging

    DEFF Research Database (Denmark)

    Wöhner, Timo; Senkbeil, S.; Olesen, T. L.;

    2015-01-01

    This paper presents the mould design for an injection moulding (IM) process for the production of a methanol container for the use in small, passive Direct Methanol Fuel Cell (DMFC) systems, which are intended to be used in behind-the-ear hearing aid systems. One of the crucial properties...... of this container is to enable venting of CO2, which is produced during the use of the DMFC system. This attribute is realized by a functional film insert in the form of a microporous, oleophobic membrane, which covers a venting hole in the injection moulded part of the container. The mould was designed to allow...... for the production of containers with different venting area and location of the venting holes and the use of different membrane thicknesses by using the same mould. Mould design and material selection are presented....

  6. Investigation of Test Methods, Material Properties, and Processes for Solar Cell Encapsulants

    Science.gov (United States)

    Willis, P. B.

    1981-01-01

    Encapsulant materials and processes for the production of cost effective, long life solar cell modules are identified, and evaluated. Ethylene vinyl acetate lamination pottant studies are conducted with respect to the time/temperature cure requirements for successful use of this compound. The time needed to produce successful gel contents are redetermined at a variety of temperatures and are related to the peroxide half life temperature curve. Formulation of the butyl acrylate syrup casting pottant is complete. The formulation contains an ultraviolet stabilizer system and is cured with an initiator that presents no shipping or handling hazards. The catalyzed syrup is stable at room temperature and has a pot life of at least an eight hour period of time. The syrup cures to a transparent rubber in 18 minutes at a temperature of 60 C.

  7. Materials Analysis of CED Nb Films Being Coated on Bulk Nb Single Cell SRF Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Xin; Reece, Charles; Palczewski, Ari; Ciovati, Gianluigi; Krishnan, Mahadevan; James, Colt; Irfan, Irfan

    2013-09-01

    This study is an on-going research on depositing a Nb film on the internal wall of bulk Nb single cell SRF cavities, via a cathodic arc Nb plasma ions source, an coaxial energetic condensation (CED) facility at AASC company. The motivation is to firstly create a homoepitaxy-like Nb/Nb film in a scale of a ~1.5GHz RF single cell cavity. Next, through SRF measurement and materials analysis, it might reveal the baseline properties of the CED-type homoepitaxy Nb films. Literally, a top-surface layer of Nb films which sustains SRF function, always grows up in homo-epitaxy mode, on top of a Nb nucleation layer. Homo-epitaxy growth of Nb must be the final stage (a crystal thickening process) of any coatings of Nb film on alternative cavity structure materials. Such knowledge of Nb-Nb homo-epitaxy is useful to create future realistic SRF cavity film coatings, such as hetero-epitaxy Nb/Cu Films, or template-layer-mitigated Nb films. One large-grain, and three fine grain bulk Nb cavities were coated. They went through cryogenic RF measurement. Preliminary results show that the Q0 of a Nb film could be as same as the pre-coated bulk Nb surface (which received a chemically-buffered polishing plus a light electro-polishing); but quality factor of two tested cavities dropped quickly. We are investigating if the severe Q-slope is caused by hydrogen incorporation before deposition, or is determined by some structural defects during Nb film growth.

  8. Calcium manganite as oxygen electrode materials for reversible solid oxide fuel cell.

    Science.gov (United States)

    Ni, Chengsheng; Irvine, John T S

    2015-01-01

    For an efficient high-temperature reversible solid oxide fuel cell (RSOFC), the oxygen electrode should be highly active for the conversion between oxygen anions and oxygen gas. CaMnO(3-δ) (CM) is a perovskite that can be readily reduced with the formation of Mn(3+) giving rise to oxygen defective phases. CM is examined here as the oxygen electrode for a RSOFC. CaMn(0.9)Nb(0.1)O(3-δ) (CMN) with Nb doping shows superior electric conductivity (125 S cm(-1) at 700 °C) compared with CM (1-5 S cm(-1) at 700 °C) in air which is also examined for comparison. X-ray diffraction (XRD) data show that CM and CMN are compatible with the widely used yttria-stabilized zirconia (YSZ) electrolyte up to 950 °C. Both materials show a thermal expansion coefficient (TEC) close to 10.8-10.9 ppm K(-1) in the temperature range between 100-750 °C, compatible with that of YSZ. Polarization curves and electrochemical impedance spectra for both fuel cell and steam electrolysis modes were investigated at 700 °C, showing that CM presented a polarization resistance of 0.059 Ω cm(2) under a cathodic bias of -0.4 V while CMN gave a polarization resistance of 0.081 Ω cm(2) under an anodic bias of 0.4 V. The phase stability up to 900 °C of these materials was investigated with thermogravimetric analysis (TGA) and variable temperature XRD. PMID:26212316

  9. Streamlining of commercial Berl saddles: A new material to improve the performance of microbial fuel cells

    International Nuclear Information System (INIS)

    Microbial fuel cell (MFC) is an upcoming technology that allows oxidizing organic matter to generate current by microorganism's activity. To render MFCs a cost-effective and energy sustainable technology, low-cost materials can be employed as support for bacteria growth and proliferation. With this purpose in mind, ceramic Berl saddles were opportunely covered by a thin and conductive carbon layer, thus obtaining an innovative low-cost anode material able to efficiently recover the electrons released by bacteria metabolisms. The conductive layer was obtained by using α-D-glucose deposition process within the following steps: impregnation, caramelization, and pyrolysis. In this way, a homogenous coating of polycrystalline graphitic carbon was successfully obtained and characterized by several methods. The carbon-coated Berl saddles were then tested as anode material in a two-compartment MFC prototype, in batch mode and using Saccharomyces cerevisiae as active microorganisms. The MFC performances were evaluated using electrochemical techniques. The carbon-coated Berl saddles showed a maximum power density of 130 mW m−2 (29.6 mA L−1) which is about 2–3 times higher than the values reported in literature by using commercial anode materials. In particular, we have carefully estimated the production and process costs of these carbon-coated Berl saddles used in our MFC prototype, obtaining a value comparable to the commercial carbon felt employed in the same MFC apparatus. All these results confirm that our innovative carbon-coated Berl saddles not only satisfy the electrical requirements, but also favor an optimal bacteria adhesion and can be produced as a low-cost anode for scaling-up MFC. - Highlights: • Berl saddles were opportunely covered by a conductive carbon layer. • New and easy electrode preparation methods offer a low-cost solution for MFC anode. • Power density using coated Berl saddles is comparable to commercial materials. • Coated

  10. Thin film solar cells from earth abundant materials growth and characterization of Cu2(ZnSn)(SSe)4 thin films and their solar cells

    CERN Document Server

    Kodigala, Subba Ramaiah

    2013-01-01

    The fundamental concept of the book is to explain how to make thin film solar cells from the abundant solar energy materials by low cost. The proper and optimized growth conditions are very essential while sandwiching thin films to make solar cell otherwise secondary phases play a role to undermine the working function of solar cells. The book illustrates growth and characterization of Cu2ZnSn(S1-xSex)4 thin film absorbers and their solar cells. The fabrication process of absorber layers by either vacuum or non-vacuum process is readily elaborated in the book, which helps for further developm

  11. Efficient Hole-Transporting Materials with Triazole Core for High-Efficiency Perovskite Solar Cells.

    Science.gov (United States)

    Choi, Hyeju; Jo, Hyeonjun; Paek, Sanghyun; Koh, Kyungkuk; Ko, Haye Min; Lee, Jae Kwan; Ko, Jaejung

    2016-02-18

    Efficient hole-transporting materials (HTMs), TAZ-[MeOTPA]2 and TAZ-[MeOTPATh]2 incorporating two electron-rich diphenylamino side arms, through direct linkage or thiophen bridges, respectively, on the C3- and C5-positions of a 4-phenyl-1,2,4-triazole core were synthesized. These synthetic HTMs with donor-acceptor type molecular structures exhibited effective intramolecular charge transfer for improving the hole-transporting properties. The structural modification of HTMs by thiophene bridging might increase intermolecular π-π stacking in the solid state and afford a better spectral response because of their increased π-conjugation length. Perovskite-based cells using TAZ-[MeOTPA]2 and TAZ-[MeOTPATh]2 as HTMs afforded high power conversion efficiencies of 10.9 % and 14.4 %, respectively, showing a photovoltaic performance comparable to that obtained using spiro-OMeTAD. These synthetically simple and inexpensive HTMs hold promise for replacing the more expensive spiro-OMeTAD in high-efficiency perovskite solar cells. PMID:26573775

  12. All solution processed tandem polymer solar cells based on thermocleavable materials

    Energy Technology Data Exchange (ETDEWEB)

    Hagemann, Ole; Krebs, Frederik C. [Risoe National Laboratory for Sustainable Energy, Polymer Department, Technical University of Denmark, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Bjerring, Morten; Nielsen, Niels Chr. [Center for Insoluble Protein Structures, Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, University of Aarhus, DK-8000 Aarhus C (Denmark)

    2008-11-15

    Multilayer tandem polymer solar cells were prepared by solution processing using thermocleavable polymer materials that allow for conversion to an insoluble state through a short thermal treatment. The problems associated with solubility during application of subsequent layers in the stack were efficiently solved. Devices comprised a transparent front cathode based on solution processed zinc oxide nanoparticles, a large band gap active layer based on a bulk heterojunction between zinc oxide and poly(3-carboxydithiophene) (P3CT) followed by a layer of PEDOT:PSS processed from water. The second cell in the stack employed a zinc oxide front cathode processed on top of the PEDOT:PSS layer from an organic solvent, a low band gap active layer based on a bulk heterojunction between zinc oxide and the novel poly(carboxyterthiophene-co-diphenylthienopyrazine) (P3CTTP) followed by a layer of PEDOT:PSS again processed from water and finally a printed silver electrode. The devices were prepared without the use of fullerenes and vacuum steps and employ only thermal treatments and orthogonal solvents. The devices exhibited operational stability in air without any form of encapsulation. (author)

  13. Characterizing automotive fuel cell materials by soft x-ray scanning transmission x-ray microscopy

    Science.gov (United States)

    Hitchcock, A. P.; Lee, V.; Wu, J.; West, M. M.; Cooper, G.; Berejnov, V.; Soboleva, T.; Susac, D.; Stumper, J.

    2016-01-01

    Proton-Exchange Membrane Fuel Cell (PEM-FC) based engines are being developed rapidly for near-term implementation in hydrogen fueled, mass production, personal automobiles. Research is focused on understanding and controlling various degradation processes (carbon corrosion, Pt migration, cold start), and reducing cost by reducing or eliminating Pt catalyst. We are using soft X-ray scanning transmission X-ray microscopy (STXM) at the S 2p, C 1s, O 1s and F 1s edges to study a variety of issues related to optimization of PEM-FC materials for automotive applications. A method to efficiently and accurately measure perfluorosulfonic acid distributions was developed and is being used to better understand how different loadings and preparation methods affect the ionomer distribution in the cathode. Progress towards an environmental cell capable of controlling the temperature and humidity of a PEM-FC sample in the STXM is described. Methods for studying the 3D chemical structure of PEM-FC are outlined.

  14. Characterizing automotive fuel cell materials by soft x-ray scanning transmission x-ray microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hitchcock, A. P., E-mail: aph@mcmaster.ca; Lee, V.; Wu, J.; Cooper, G. [Chemistry & Chemical Biology, McMaster University, Hamilton, ON, L8S 4M1 (Canada); West, M. M.; Berejnov, V. [Faculty of Health Sciences Electron Microscopy, McMaster University, Hamilton, ON L8N 3Z5 (Canada); Soboleva, T.; Susac, D.; Stumper, J. [Automotive Fuel Cell Cooperation Corp., Burnaby BC V5J 5J8 (Canada)

    2016-01-28

    Proton-Exchange Membrane Fuel Cell (PEM-FC) based engines are being developed rapidly for near-term implementation in hydrogen fueled, mass production, personal automobiles. Research is focused on understanding and controlling various degradation processes (carbon corrosion, Pt migration, cold start), and reducing cost by reducing or eliminating Pt catalyst. We are using soft X-ray scanning transmission X-ray microscopy (STXM) at the S 2p, C 1s, O 1s and F 1s edges to study a variety of issues related to optimization of PEM-FC materials for automotive applications. A method to efficiently and accurately measure perfluorosulfonic acid distributions was developed and is being used to better understand how different loadings and preparation methods affect the ionomer distribution in the cathode. Progress towards an environmental cell capable of controlling the temperature and humidity of a PEM-FC sample in the STXM is described. Methods for studying the 3D chemical structure of PEM-FC are outlined.

  15. Characterizing automotive fuel cell materials by soft x-ray scanning transmission x-ray microscopy

    International Nuclear Information System (INIS)

    Proton-Exchange Membrane Fuel Cell (PEM-FC) based engines are being developed rapidly for near-term implementation in hydrogen fueled, mass production, personal automobiles. Research is focused on understanding and controlling various degradation processes (carbon corrosion, Pt migration, cold start), and reducing cost by reducing or eliminating Pt catalyst. We are using soft X-ray scanning transmission X-ray microscopy (STXM) at the S 2p, C 1s, O 1s and F 1s edges to study a variety of issues related to optimization of PEM-FC materials for automotive applications. A method to efficiently and accurately measure perfluorosulfonic acid distributions was developed and is being used to better understand how different loadings and preparation methods affect the ionomer distribution in the cathode. Progress towards an environmental cell capable of controlling the temperature and humidity of a PEM-FC sample in the STXM is described. Methods for studying the 3D chemical structure of PEM-FC are outlined

  16. Development of a sub-scale dynamics model for pressure relaxation of multi-material cells in Lagrangian hydrodynamics

    Directory of Open Access Journals (Sweden)

    Canfield T.R.

    2011-01-01

    Full Text Available We have extended the Sub-Scale Dynamics (SSD closure model for multi-fluid computational cells. Volume exchange between two materials is based on the interface area and a notional interface translation velocity, which is derived from a linearized Riemann solution. We have extended the model to cells with any number of materials, computing pressure-difference-driven volume and energy exchange as the algebraic sum of pairwise interactions. In multiple dimensions, we rely on interface reconstruction to provide interface areas and orientations, and centroids of material polygons. In order to prevent unphysically large or unmanageably small material volumes, we have used a flux-corrected transport (FCT approach to limit the pressure-driven part of the volume exchange. We describe the implementation of this model in two dimensions in the FLAG hydrodynamics code. We also report on Lagrangian test calculations, comparing them with others made using a mixed-zone closure model due to Tipton, and with corresponding calculations made with only single-material cells. We find that in some cases, the SSD model more accurately predicts the state of material in mixed cells. By comparing the algebraic forms of both models, we identify similar dependencies on state and dynamical variables, and propose explanations for the apparent higher fidelity of the SSD model.

  17. Fundamental Studies of the Durability of Materials for Interconnects in Solid Oxide Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Frederick S. Pettit; Gerald H. Meier

    2006-06-30

    Ferritic stainless steels are a leading candidate material for use as an SOFC interconnect, but have the problem of forming volatile chromia species that lead to cathode poisoning. This project has focused both on optimization of ferritic alloys for SOFC applications and evaluating the possibility of using alternative materials. The initial efforts involved studying the oxidation behavior of a variety of chromia-forming ferritic stainless steels in the temperature range 700-900 C in atmospheres relevant to solid oxide fuel cell operation. The alloys exhibited a wide variety of oxidation behavior based on composition. A method for reducing the vaporization is to add alloying elements that lead to the formation of a thermally grown oxide layer over the protective chromia. Several commercial steels form manganese chromate on the surface. This same approach, combined with observations of TiO{sub 2} overlayer formation on the chromia forming, Ni-based superalloy IN 738, has resulted in the development of a series of Fe-22 Cr-X Ti alloys (X=0-4 wt%). Oxidation testing has indicated that this approach results in significant reduction in chromia evaporation. Unfortunately, the Ti also results in accelerated chromia scale growth. Fundamental thermo-mechanical aspects of the durability of solid oxide fuel cell (SOFC) interconnect alloys have also been investigated. A key failure mechanism for interconnects is the spallation of the chromia scale that forms on the alloy, as it is exposed to fuel cell environments. Indentation testing methods to measure the critical energy release rate (Gc) associated with the spallation of chromia scale/alloy systems have been evaluated. This approach has been used to evaluate the thermomechanical stability of chromia films as a function of oxidation exposure. The oxidation of pure nickel in SOFC environments was evaluated using thermogravimetric analysis (TGA) to determine the NiO scaling kinetics and a four-point probe was used to measure

  18. Influence of Dental Alloys and an All-Ceramic Material on Cell Viability and Interleukin-1beta Release in a Three-Dimensional Cell Culture Model

    OpenAIRE

    ÖZEN, Jülide; Ural, Ali Uğur; Dalkiz, Mehmet; BEYDEMİR, Bedri

    2005-01-01

    The purpose of this study was to determine the influence of various types of dental casting alloys and ceramic upon cell viability and the synthesis of IL-1beta (b) in a three-dimensional cell culture system consisting of human gingival fibroblast, and to determine their effect in gingival inflammation. Au-Pt-In alloy (Pontostar), Ni-Cr-Mo alloy (Remanium-CS), a titanium alloy (Ti-6Al-4V), copper (Cu), and an all ceramic (In-Ceram) were used as test materials. The materials were exposed to a ...

  19. Efficiency enhancement of perovskite solar cells via incorporation of phenylethenyl side arms into indolocarbazole-based hole transporting materials

    Science.gov (United States)

    Petrikyte, Ieva; Zimmermann, Iwan; Rakstys, Kasparas; Daskeviciene, Maryte; Malinauskas, Tadas; Jankauskas, Vygintas; Getautis, Vytautas; Nazeeruddin, Mohammad Khaja

    2016-04-01

    Small-molecule hole transporting materials based on an indolocarbazole core were synthesized and incorporated into perovskite solar cells, which displayed a power conversion efficiency up to 15.24%. The investigated hole transporting materials were synthesized in three steps from commercially available and relatively inexpensive starting materials without using expensive catalysts. Various electro-optical measurements (UV-vis, CV, hole mobility, DSC, TGA, ionization potential) have been carried out to characterize the new hole transporting materials.Small-molecule hole transporting materials based on an indolocarbazole core were synthesized and incorporated into perovskite solar cells, which displayed a power conversion efficiency up to 15.24%. The investigated hole transporting materials were synthesized in three steps from commercially available and relatively inexpensive starting materials without using expensive catalysts. Various electro-optical measurements (UV-vis, CV, hole mobility, DSC, TGA, ionization potential) have been carried out to characterize the new hole transporting materials. Electronic supplementary information (ESI) available: Synthesis procedures, device construction and characterisation details. See DOI: 10.1039/c6nr01275b

  20. Design of Mechanical Properties of Open-Cell Porous Materials Based on μCT Study of Commercial Foams

    OpenAIRE

    Skibinski Jakub; Cwieka Karol; Wejrzanowski Tomasz; Kurzydlowski Krzysztof J.

    2015-01-01

    In the present paper numerical design of mechanical properties of open-cell porous materials is addressed. A detailed knowledge of mechanisms and parameters determining mechanical properties (i.e. Young’s Modulus, Poisson’s Ratio) of foams is essential for applications such as energy absorbers or lightweight construction materials. The foam structures were designed using procedure based on Laguerre-Voronoi tessellations (LVT) with micro-computed tomography of commercial foams used as referenc...

  1. KARAKTERISASI KITIN DEASETILASE TERMOSTABIL ISOLAT BAKTERI ASAL PANCURAN TUJUH, BATURADEN, JAWA TENGAH [Characterization of Thermostable Chitin Deacetylase from Bacteria Strain Pancuran Tujuh, Baturaden, Center of Java

    Directory of Open Access Journals (Sweden)

    Deuxianto Hendarsyah3

    2006-04-01

    Full Text Available Chitin deacetylase is the enzymes that has important role in converting chitin to chitosan. In nature, chitin is the second most abundant natural biopolymer after cellulose. Generally, chitin easily obtained from outer shell of crustaceans, arthropods, and also detectable on cell wall of some type of fungal (Zygomycetes. The chitin deacetylase was isolated from Bacillus sp PT2-3. It was found that the highest specific activity was attained at pH 8 60°C. The addition of 5 mM Zn2+ and 5 mM Mn2+ increased the specific activity of the enzyme, 4.39% and 7.8%, respectively, and the increase was only 2.19% when the addition was 2 mM Mn2+. On the contrary the addition of Ca2+, Mg2+ and Fe2+ decrease the specific activity 46.83%, 41.22% and 47.32%, respectively. The enzyme activity was relatively stable at 60°C for 60 minutes, while lengthen the time to 90 minutes, decreased the activity 15.05 %, and the decrease was 26.13% at temperature of 70°C for 180 minutes.

  2. Thermal Characteristics of Multilayer Insulation Materials for Flexible Thin-Film Solar Cell Array of Stratospheric Airship

    OpenAIRE

    Kangwen Sun; Qinzhen Yang; Yang Yang; Shun Wang; Jianming Xu; Qiang Liu; Yong Xie; Peng Lou

    2014-01-01

    Flexible thin-film solar cell is an efficient energy system on the surface of stratospheric airship for utilizing the solar energy. In order to ensure the normal operation of airship platform, the thermal control problem between the flexible thin-film solar cell and the airship envelope should be properly resolved. In this paper, a multilayer insulation material (MLI) is developed first, and low temperature environment test is carried out to verify the insulation effect of MLI. Then, a therma...

  3. Characterization & Modification of Copper and Iron Oxide Nanoparticles for Application as Absorber Material in Silicon based Thin Film Solar Cells

    OpenAIRE

    Nuys, Maurice

    2015-01-01

    The present thesis deals with the characterization and modification of semiconducting copper oxide (CuO, Cu2O) and iron oxide (gamma-Fe2O3, alpha-Fe2O3) nanoparticles, which provide a basis for an innovative solar cell concept involving nanoparticles composed of almost unlimitedly available elements as absorber material in thin film solar cells. This approach is promising to meet the requirements of increasing the production capacity and lowering the production costs if the nanoparticles exhi...

  4. 15th Workshop on Crystalline Silicon Solar Cells and Modules: Materials and Processes; Extended Abstracts and Papers

    Energy Technology Data Exchange (ETDEWEB)

    Sopori, B. L.

    2005-11-01

    The National Center for Photovoltaics sponsored the 15th Workshop on Crystalline Silicon Solar Cells & Modules: Materials and Processes, held in Vail, CO, August 7-10, 2005. This meeting provided a forum for an informal exchange of technical and scientific information between international researchers in the photovoltaic and relevant non-photovoltaic fields. The workshop addressed the fundamental properties of PV silicon, new solar cell designs, and advanced solar cell processing techniques. A combination of oral presentations by invited speakers, poster sessions, and discussion sessions reviewed recent advances in crystal growth, new cell designs, new processes and process characterization techniques, and cell fabrication approaches suitable for future manufacturing demands. The theme of this year's meeting was 'Providing the Scientific Basis for Industrial Success.' Specific sessions during the workshop included: Advances in crystal growth and material issues; Impurities and defects in Si; Advanced processing; High-efficiency Si solar cells; Thin Si solar cells; and Cell design for efficiency and reliability module operation. The topic for the Rump Session was ''Si Feedstock: The Show Stopper'' and featured a panel discussion by representatives from various PV companies.

  5. Permeation measurement of gestodene for some biodegradable materials using Franz diffusion cells.

    Science.gov (United States)

    Liu, Danhua; Zhang, Chong; Zhang, Xiaowei; Zhen, Zhu; Wang, Ping; Li, Jianxin; Yi, Dongxu; Jin, Ying; Yang, Dan

    2015-09-01

    Biodegradable poly(d,l-lactide) (PDLLA), Poly(trimethylene carbonate) (PTMC), polycaprolactone (PCL), poly(caprolactone-co-d,l-lactide) (PCDLLA) and poly(trimethylene carbonate-co-caprolactone) (PTCL) are recently used for clinical drug delivery system such as subcutaneous contraceptive implant capsule due to their biodegradable properties that they could possess long-term stable performance in vivo without removal, however their permeation rate is unknown. In the work, biodegradable material membranes were prepared by solvent evaporation using chloroform, and commercial silicone rubber membrane served as a control. Gestodene was used as a model drug. Gestodene has high biologic progestational activity which allows for high contraceptive reliability at very low-dose levels. The permeation rate of gestodene for several biodegradable materials was evaluated. In vitro diffusion studies were done using Franz diffusion cells with a diffusion area of 1.33 cm(2). Phosphate buffer solution (PBS, pH 7.4), 10% methanol solution and distilled water were taken in donor and receiver chambers at temperature of 37 °C respectively. The in vitro experiments were conducted over a period of 24 h during which samples were collected at regular intervals. The withdrawn samples were appropriately diluted and measured on UV-vis spectrophotometer at 247 nm. Conclusion data from our study showed that permeation rate of PCDLLA with CL ratio more than 70% could be more excellent than commercial silicone rubber membrane. They may be suitable as a candidate carrier for gestodene subcutaneous contraceptive implants in contraceptive fields. PMID:27134544

  6. Characterization of tantalum doped lanthanum strontium ferrite as cathode materials for solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Natali Sora, Isabella, E-mail: isabella.natali-sora@unibg.it [INSTM R.U. Bergamo and Department of Engineering and Applied Sciences, University of Bergamo, Viale Marconi 5, Dalmine, BG 24044 (Italy); Felice, Valeria [INSTM R.U. Bergamo and Department of Engineering and Applied Sciences, University of Bergamo, Viale Marconi 5, Dalmine, BG 24044 (Italy); Zurlo, Francesca; Licoccia, Silvia; Di Bartolomeo, Elisabetta [Department of Chemical Science and Technologies & NAST Center University of Rome “Tor Vergata”, Via della Ricerca Scientifica, 00133 (Italy)

    2015-11-05

    The phase relations and crystal structures of La{sub 1−x}Sr{sub x}Fe{sub 1−y}Ta{sub y}O{sub 3} in the compositional range x = 0–0.60, y = 0–0.20 were investigated by powder X-ray diffraction (XRD). The formal concentration of Fe{sup 4+} in the La{sub 1−x}Sr{sub x}Fe{sub 1−y}Ta{sub y}O{sub 3±w} (LSFT) system was calculated and related to the electrical/electrochemical properties. To investigate the electrochemical behaviour as cathode material for SOFCs, impedance measurements were performed on LSFT/electrolyte/LSFT symmetrical cells by using La{sub 0.8}Sr{sub 0.2}Ga{sub 0.8}Mg{sub 0.2}O{sub 3}, (LSGM) as electrolyte material. The lowest area specific resistance (ASR), derived from the polarization resistance (R{sub p}), 1 Ω cm{sup 2} at 750 °C, was measured for the LSFT compound doped with x = 0.40 and y = 0.05. - Highlights: • The lowest area specific resistance was obtained with Sr = 0.40 and Ta = 0.05. • The activation energies E{sub a} are in the range of 1.3–1.6 eV. • The samples were single phase when Sr = 0, 0.20, 0.40, and 0.6 and Ta = 0.05. • A predictive trend of the electric conductivity is proposed.

  7. The comparison between gallium arsenide and indium gallium arsenide as materials for solar cell performance using Silvaco application

    Energy Technology Data Exchange (ETDEWEB)

    Zahari, Suhaila Mohd; Norizan, Mohd Natashah; Mohamad, Ili Salwani; Osman, Rozana Aina Maulat; Taking, Sanna [School of Microelectronic Engineering, Universiti Malaysia Perlis, Kampus Pauh Putra, 02600 Arau, Perlis (Malaysia)

    2015-05-15

    The work presented in this paper is about the development of single and multilayer solar cells using GaAs and InGaAs in AM1.5 condition. The study includes the modeling structure and simulation of the device using Silvaco applications. The performance in term of efficiency of Indium Gallium Arsenide (InGaAs) and GaAs material was studied by modification of the doping concentration and thickness of material in solar cells. The efficiency of the GaAs solar cell was higher than InGaAs solar cell for single layer solar cell. Single layer GaAs achieved an efficiency about 25% compared to InGaAs which is only 2.65% of efficiency. For multilayer which includes both GaAs and InGaAs, the output power, P{sub max} was 8.91nW/cm² with the efficiency only 8.51%. GaAs is one of the best materials to be used in solar cell as a based compared to InGaAs.

  8. Indirect Determination of Material Properties of Closed-Cell Metal Foam: Comparison of Voxel and Tetrahedral Finite Element Models

    Czech Academy of Sciences Publication Activity Database

    Jiroušek, Ondřej; Koudelka_ml., Petr; Zlámal, Petr

    Stirlingshire: Civil-Comp Press, 2012 - (Topping, B.), s. 243-253 ISBN 978-1-905088-55-3. [Engineering Computational Technology 2012 /8./. Dubrovník (HR), 04.09.2012-07.09.2012] Grant ostatní: GA ČR(CZ) GAP105/12/0824 Institutional support: RVO:68378297 Keywords : metal foam * closed-cell material * orthotropic material properties * indirect methods * micro-CT * voxel models * tetrahedral models Subject RIV: JI - Composite Materials http://www.ctresources.info/ccp/pdf.html?id=7235

  9. Understanding the influence of the electrode material on microbial fuel cell performance

    Science.gov (United States)

    Sanchez, David V. P.

    In this thesis, I deploy sets of electrodes into microbial fuel cells (MFC), characterize their performance, and evaluate the influence of both platinum catalysts and carbon-based electrodes on current production. The platinum work centers on improving current production by optimizing the use of the catalyst using nano-fabrication techniques. The carbon-electrode work seeks to determine the influence of the bare electrode on biofilm-anode current production. The development of electrodes for MFCs has boomed over the past decade, however, experiments aimed at identifying how catalyst deposition methods and electrode properties influence current production have been limited. The research conducted here is an attempt to expand this knowledge base for platinum catalysts and carbon electrodes. In the initial chapters (4 and 5), I discuss our attempt to decrease catalyst loadings while increasing current production through the use of platinum nanoparticles. The results demonstrate that incorporating platinum nanoparticles throughout the anode and cathode is an efficient means of increasing MFC current production relative to surface deposition because it increases catalyst surface area. The later chapters (chapters 6 and 7) develop an understanding of the importance of electrode properties (i.e. surface area, activation resistance, conductivity, surface morphology) by electrochemically evaluating well-studied anode-respiring pure cultures on different carbon electrode architectures. Two different architectures are produced by using tubular and platelet shaped constituent materials (i.e. carbon fibers and graphene nanoplatelets) and the morphologies of the electrodes are varied by altering the size of the constituent material. The electrodes are characterized and evaluated in MFCs using either Shewanella oneidensis MR-1 or Geobacter sulfurreducens as the innoculant because their bioelectrochemical physiologies are the most documented in the literature. Using the

  10. Cell death effects of resin-based dental material compounds and mercurials in human gingival fibroblasts

    Energy Technology Data Exchange (ETDEWEB)

    Reichl, Franz-Xaver [Walther-Straub-Institute of Pharmacology and Toxicology, Munich (Germany); Ludwig-Maximilians-University, Department of Operative Dentistry and Periodontology, Munich (Germany); Esters, Magali; Simon, Sabine; Seiss, Mario [Walther-Straub-Institute of Pharmacology and Toxicology, Munich (Germany); Kehe, Kai [Bundeswehr Institute of Pharmacology and Toxicology, Munich (Germany); Kleinsasser, Norbert [University of Regensburg, Head and Neck Surgery, Department of Otolaryngology, Regensburg (Germany); Folwaczny, Matthias; Glas, Juergen; Hickel, Reinhard [Ludwig-Maximilians-University, Department of Operative Dentistry and Periodontology, Munich (Germany)

    2006-06-15

    In order to test the hypothesis that released dental restorative materials can reach toxic levels in human oral tissues, the cytotoxicities of the resin-based dental (co)monomers hydroxyethylmethacrylate (HEMA), triethyleneglycoldimethacrylate (TEGDMA), urethanedimethacrylate (UDMA), and bisglycidylmethacrylate (BisGMA) compared with methyl mercury chloride (MeHgCl) and the amalgam component mercuric chloride (HgCl{sub 2}) were investigated on human gingival fibroblasts (HGF) using two different test systems: (1) the modified XTT-test and (2) the modified H 33342 staining assay. The HGF were exposed to various concentrations of the test-substances in all test systems for 24 h. All tested (co)monomers and mercury compounds significantly (P<0.05) decreased the formazan formation in the XTT-test. EC{sub 50} values in the XTT assay were obtained as half-maximum-effect concentrations from fitted curves. Following EC{sub 50} values were found (mean [mmol/l]; s.e.m. in parentheses; n=12; * significantly different to HEMA): HEMA 11.530 (0.600); TEGDMA* 3.460 (0.200); UDMA* 0.106 (0.005); BisGMA* 0.087 (0.001); HgCl{sub 2}* 0.013 (0.001); MeHgCl* 0.005 (0.001). Following relative toxicities were found: HEMA 1; TEGDMA 3; UDMA 109; BisGMA 133; HgCl{sub 2} 887; MeHgCl 2306. A significant (P<0.05) increase of the toxicity of (co)monomers and mercurials was found in the XTT-test in the following order: HEMA < TEGDMA < UDMA < BisGMA < HgCl{sub 2} < MeHgCl. TEGDMA and MeHgCl induced mainly apoptotic cell death. HEMA, UDMA, BisGMA, and HgCl{sub 2} induced mainly necrotic cell death. The results of this study indicate that resin composite components have a lower toxicity than mercury from amalgam in HGF. HEMA, BisGMA, UDMA, and HgCl{sub 2} induced mainly necrosis, but it is rather unlikely that eluted substances (solely) can reach concentrations, which might induce necrotic cell death in the human physiological situation, indicating that other (additional) factors may be involved in

  11. Investigation of molybdenum-44.5%rhenium as cell wall material in an AMTEC based space power system

    International Nuclear Information System (INIS)

    A new generation of radioisotope space power systems based on AMTEC (Alkali Metal Thermal to Electrical Conversion) technology is presently being developed. The future application of this technology, as the electrical power system for outer planet deep space missions, is ultimately dependent on it being robust enough to withstand the mission's operational environments (high temperatures, dynamic loadings, long mission durations etc). One of the critical material selections centers on the cell wall whose physical and chemical properties must provide it with sufficient strength and material compatibility to successfully complete the mission. Niobium-1%zirconium has been selected as the baseline cell wall material with a molybdenum/rhenium alloy being the cell wall backup material. While these refractory materials have been commercially available for a number of years, several of their physical and mechanical properties have not been completely characterized especially within the expected operating parameters of an AMTEC based space power system. Additional characterization of the selected refractory alloys was initiated by fabricating mechanical test specimens out of ∼0.5 mm (0.020'') thick sheets of material. Test specimens were heat treated at 1073K and 1198K for up to 150 hours under an argon cover gas containing small concentrations of oxygen. Room temperature and high temperature (1073K/1198K) mechanical tests were performed to determine the effect of time, temperature, and atmosphere on the mechanical properties of the refractory alloys. In addition, since the fabrication of AMTEC cell walls requires the welding of sheet material into a cylindrical shape, preliminary electron beam welding studies were performed. Comparison of the various test results obtained on Mo-44.5%Re and Nb-1%Zr samples are discussed

  12. Modified carbons with optimized electrochemical properties as anode material in lithium ion cells

    International Nuclear Information System (INIS)

    Lithium ion cells are widely used rechargeable batteries for applications in laptops or mobile phones. Purpose of this work is the optimization of the commonly used graphite intercalation anodes. During the first charge/discharge cycles electrolyte decomposition takes place at the anode followed by formation of a film, which hinders further decomposition of the electrolyte. This reaction can be controlled by the surface composition of the anodes. In this work the surface composition and structure of different graphites were changed by gas treatment. Referring to the 'dangling bonds' model, the activated graphite surface with free bonds and adsorption places was treated with a reactive gas. The applicability of the obtained modified graphites as electrode materials was tested in charge/discharge studies. The results were correlated with surface properties of the graphites. For this purpose the specific surface area of the differently treated graphites was determined by BET measurements. The chemical composition and the distribution of the surface groups was measured by electron scanning chemical analysis (ESCA). Optical pictures of the surfaces were obtained by scanning electron microscopy (SEM). (author)

  13. Structure, physicochemical properties and in vitro fermentation of enzymatically degraded cell wall materials from apples.

    Science.gov (United States)

    Förster, S; Dongowski, G; Kunzek, H

    2002-06-01

    Cell wall materials (CWM) prepared from apple parenchyma tissue by treatment with commercial enzymes for maceration, mash fermentation and liquefaction were characterised with regard to their composition and structure as well as their physicochemical and physiological properties. Increasing enzymatic degradation of the CWM resulted in growing loss of the pectin matrix, decreasing porosity as well as increasing particle aggregation. Due to these structural alterations the water binding, the viscoelastic properties of the CWM-water-suspensions and the in vitro fermentation, forming short chain fatty acids, were reduced. The investigations showed that interrelations exist between enzymatic treatment and changes of (i) structure and state of matrices (evaluated by means of thermal analysis), (ii) physicochemical properties and (iii) physiological properties. So the application of liquefying enzymes can lead to a complete removal of the pectin matrix, causing an essentially improved thermal stability of the CWM preparation, but strongly reduced water binding and reduced structure-forming properties into the CWM-water-suspensions. The formation of short-chain fatty acids during in vitro fermentation of the CWM preparations by fresh human faeces flora depended on the portion and the state of the pectin matrix and the cellulose network, respectively. PMID:12108214

  14. Charge generation in organic solar cell materials studied by terahertz spectroscopy

    KAUST Repository

    Scarongella, M.

    2015-09-09

    We have investigated the photophysics in neat films of conjugated polymer PBDTTPD and its blend with PCBM using terahertz time-domain spectroscopy. This material has very high efficiency when used in organic solar cells. We were able to identify a THz signature for bound excitons in neat PBDTTPD films, pointing to important delocalization in those excitons. Then, we investigated the nature and local mobility (orders of magnitude higher than bulk mobility) of charges in the PBDTTPPD:PCBM blend as a function of excitation wavelength, fluence and pump-probe time delay. At low pump fluence (no bimolecular recombination phenomena), we were able to observe prompt and delayed charge generation components, the latter originating from excitons created in neat polymer domains which, thanks to delocalization, could reach the PCBM interface and dissociate to charges on a time scale of 1 ps. The nature of the photogenerated charges did not change between 0.5 ps and 800 ps after photo-excitation, which indicated that the excitons split directly into relatively free charges on an ultrafast time scale. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  15. 3,4-Phenylenedioxythiophene (PheDOT) Based Hole-Transporting Materials for Perovskite Solar Cells.

    Science.gov (United States)

    Chen, Jian; Chen, Bai-Xue; Zhang, Fang-Shuai; Yu, Hui-Juan; Ma, Shuang; Kuang, Dai-Bin; Shao, Guang; Su, Cheng-Yong

    2016-04-01

    Two new electron-rich molecules based on 3,4-phenylenedioxythiophene (PheDOT) were synthesized and successfully adopted as hole-transporting materials (HTMs) in perovskite solar cells (PSCs). X-ray diffraction, absorption spectra, photoluminescence spectra, electrochemical properties, thermal stabilities, hole mobilities, conductivities, and photovoltaic parameters of PSCs based on these two HTMs were compared with each other. By introducing methoxy substituents into the main skeleton, the energy levels of PheDOT-core HTM were tuned to match with the perovskite, and its hole mobility was also improved (1.33×10(-4)  cm(2)  V(-1)  s(-1) , being higher than that of spiro-OMeTAD, 2.34×10(-5)  cm(2)  V(-1)  s(-1) ). The PSC based on MeO-PheDOT as HTM exhibits a short-circuit current density (Jsc ) of 18.31 mA cm(-2) , an open-circuit potential (Voc ) of 0.914 V, and a fill factor (FF) of 0.636, yielding an encouraging power conversion efficiency (PCE) of 10.64 % under AM 1.5G illumination. These results give some insight into how the molecular structures of HTMs affect their performances and pave the way for developing high-efficiency and low-cost HTMs for PSCs. PMID:26840766

  16. A critical review of cell culture strategies for modelling intracortical brain implant material reactions.

    Science.gov (United States)

    Gilmour, A D; Woolley, A J; Poole-Warren, L A; Thomson, C E; Green, R A

    2016-06-01

    The capacity to predict in vivo responses to medical devices in humans currently relies greatly on implantation in animal models. Researchers have been striving to develop in vitro techniques that can overcome the limitations associated with in vivo approaches. This review focuses on a critical analysis of the major in vitro strategies being utilized in laboratories around the world to improve understanding of the biological performance of intracortical, brain-implanted microdevices. Of particular interest to the current review are in vitro models for studying cell responses to penetrating intracortical devices and their materials, such as electrode arrays used for brain computer interface (BCI) and deep brain stimulation electrode probes implanted through the cortex. A background on the neural interface challenge is presented, followed by discussion of relevant in vitro culture strategies and their advantages and disadvantages. Future development of 2D culture models that exhibit developmental changes capable of mimicking normal, postnatal development will form the basis for more complex accurate predictive models in the future. Although not within the scope of this review, innovations in 3D scaffold technologies and microfluidic constructs will further improve the utility of in vitro approaches. PMID:26994876

  17. Studies on metal catalysts and carbon materials for fuel cell applications

    Science.gov (United States)

    Zhang, Gaixia

    As a potential candidate for an environmentally benign and highly efficient electric power generation technology, proton exchange membrane fuel cells (PEMFC) are now attracting great interest for various applications. The main objective of this project has been to investigate the interfacial interaction of Pt nanoparticles with their carbon supports, so as to determine ways to optimise the catalyst electrode and to increase its catalytic activity, thereby enhancing PEM fuel cell performance. We first studied the interfacial interaction (leading to adhesion) of Pt nanoparticles evaporated onto untreated and Ar+-treated highly oriented pyrolytic graphite surfaces, with, respectively, low and high surface defect densities; HOPG was used as a model for carbon nanotubes (CNTs) and carbon fibers. We found that those Pt nanoparticles have very weak interactions with their pristine carbon material supports, with no evidence of compound formation between them. Our analysis, however, indicated that the adhesion of Pt nanoparticles to their supports can be enhanced, using ion beams, plasmas, or other treatments to establish defects on the carbon substrate surface. In addition, by using multicomponent XPS analysis with symmetric lineshapes for each Pt4f spectral component (4f7/2,5/2), we attributed the component peaks to the existence of (i) surface oxidation on the platinum nanoparticles, and different electronic configurations of (ii) surface and (iii) bulk Pt atoms. One way of enhancing strong adhesion between them is by chemical functionalization of the support. Using mixed H2SO4/HNO3 acid treatments, we have characterized the surface chemistry of functionalized carbon fiber paper by combining infrared, Raman and X-ray photoelectron spectroscopies, to give new insights into the often-used oxidation of graphene-containing materials. We have, for the first time, demonstrated the presence of transient O-, N- and S-containing species during the oxidation process, as well as

  18. Composite cathode materials development for intermediate temperature solid oxide fuel cell systems

    Science.gov (United States)

    Qin, Ya

    Solid oxide fuel cell (SOFC) systems are of particular interest as electrochemical power systems that can operate on various hydrocarbon fuels with high fuel-to-electrical energy conversion efficiency. Within the SOFC stack, La0.8Sr 0.2Ga0.8Mg0.115Co0.085O3-delta (LSGMC) has been reported as an optimized composition of lanthanum gallate based electrolytes to achieve higher oxygen ionic conductivity at intermediate temperatures, i.e., 500-700°C. The electrocatalytic properties of interfaces between LSGMC electrolytes and various candidate intermediate-temperature SOFC cathodes have been investigated. Sm0.5Sr0.5CoO 3-delta (SSC), and La0.6Sr0.4Co0.2Fe 0.8O3-delta (LSCF), in both pure and composite forms with LSGMC, were investigated with regards to both oxygen reduction and evolution, A range of composite cathode compositions, having ratios of SSC (in wt.%) with LSGMC (wt.%) spanning the compositions 9:1, 8:2, 7:3, 6:4 and 5:5, were investigated to determine the optimal cathode-electrolyte interface performance at intermediate temperatures. All LSGMC electrolyte and cathode powders were synthesized using the glycine-nitrate process (GNP). Symmetrical electrochemical cells were investigated with three-electrode linear dc polarization and ac impedance spectroscopy to characterize the kinetics of the interfacial reactions in detail. Composite cathodes were found to perform better than the single phase cathodes due to significantly reduced polarization resistances. Among those composite SSC-LSGMC cathodes, the 7:3 composition has demonstrated the highest current density at the equivalent overpotential values, indicating that 7:3 is an optimal mixing ratio of the composite cathode materials to achieve the best performance. For the composite SC-LSGMC cathode/LSGMC interface, the cathodic overpotential under 1 A/cm2 current density was as low as 0.085 V at 700°C, 0.062V at 750°C and 0.051V at 800°C in air. Composite LSCF-LSGMC cathode/LSGMC interfaces were found to have

  19. Production of low cost single crystal silicon solar cells using local material and recycled Si saw-dust

    International Nuclear Information System (INIS)

    Silicon material due to its abundance in nature and maximum conversion efficiency, has a vide range of application in opto-electronic and photovoltaic devices, such as ICs, thin film transistors and solar cells. The cost of the solar cells is the main hindrance in competing solar energy with other form of energy resources. The production of Si material using locally available indigenous silicon ores will reduce the cost silicon solar cells and will help to promote solar energy applications in the country. Silicon ores, Quartz and Sand, were collected from various parts of the country and analyzed. The purification processes of Silicon to produce high purity silicon are discussed. The cost comparison of locally produced and imported silicon material shows that 15% to 20% cheaper material can be produced locally. In order to reduce the cost further, the silicon saw dust wasted during wafering process are analyzed. The undesirable impurities from silicon saw dust can be removed. The reusing of sawdust will produce 10% cheaper silicon solar cells. (author)

  20. Advanced nanostructured materials and their application for improvement of sun-light harvesting and efficiency of solar cells

    Science.gov (United States)

    Dimova-Malinovska, D.

    2016-02-01

    This review describes the application of different nanostructured materials in solar cells technology for improvement of sun-light harvesting and their efficiency. Several approaches have recently been proposed to increase the efficiency of solar cells above the theoretical limit which are based on a “photon management” concept that employs such phenomena as: (i) down-conversion, and (ii) surface plasmon resonance effect (iii) decreasing of the loss due to the reflection of the radiation, (iv) increasing of the reflection from the back contact, v) increasing of the effective solar cells surface, etc. The results demonstrate the possibility for to increasing of light harvesting, short circuit current and efficiency by application of nanomaterials in thin film and hetero-junction (HJ) solar cells. The first promising results allow an expectation for application of advanced nanomaterials in the 3d generation solar cells.

  1. 16th Workshop on Crystalline Silicon Solar Cells and Modules: Materials and Processes; Program, Extended Abstracts, and Papers

    Energy Technology Data Exchange (ETDEWEB)

    Sopori, B. L.

    2006-08-01

    The National Center for Photovoltaics sponsored the 16th Workshop on Crystalline Silicon Solar Cells and Modules: Materials and Processes held August 6-9, 2006 in Denver, Colorado. The workshop addressed the fundamental properties of PV-Si, new solar cell designs, and advanced solar cell processing techniques. It provided a forum for an informal exchange of technical and scientific information between international researchers in the photovoltaic and relevant non-photovoltaic fields. The Workshop Theme was: "Getting more (Watts) for Less ($i)". A combination of oral presentations by invited speakers, poster sessions, and discussion sessions reviewed recent advances in crystal growth, new cell structures, new processes and process characterization techniques, and cell fabrication approaches suitable for future manufacturing demands. The special sessions included: Feedstock Issues: Si Refining and Purification; Metal-impurity Engineering; Thin Film Si; and Diagnostic Techniques.

  2. Analysis of antigen-specific, Ig-restricted cell-free material made by I-J+ Ly-1 cells (Ly-1 TsiF) that induces Ly-2+ cells to express suppressive activity.

    Science.gov (United States)

    Yamauchi, K; Murphy, D; Cantor, H; Gershon, R K

    1981-11-01

    A set of T cells defined by a unique profile of cell surface alloantigens (phenotype Ly-1+2-; Qa-1+; I-J+) produces biologically active cell-free material(s) (Ly-1 TsiF) which induces another T cell set (cell surface phenotype Ly-1,2+; I-J/; Qa-1+) to participate in the suppression of primary immune responses to heterologous erythrocytes. The suppression is specific for the inducing antigen, and the Ly-1 TsiF binds antigen in a specific way. The activity of Ly-1 TsiF can be removed by anti-I-J immunosorbents and will not be expressed if the functional producer and acceptor cells do not share gene products that are encoded in or are tightly linked to the VH portion of the Ig complex. There is no requirement for the Ly-1 TsiF and its acceptor cell(s) to share major histocompatibility complex gene products. Thus, for optimal induction of antigen-specific suppression by cell-gree materials from Ly-1 T cells, three necessary conditions must be met: (a) antigen recognition by Ly-1 TsiF; (b) the expression of I-J gene products and (c) identify of VH-linked Ig locus gene products (or other products influenced by those genes) on both the inducer molecule and its acceptor cell. The role of the Ig-linked restriction is particularly intriguing, and its possible meaning is considered in detail. PMID:6173228

  3. Lipid-assisted microinjection: introducing material into the cytosol and membranes of small cells.

    OpenAIRE

    Laffafian, I; Hallett, M B

    1998-01-01

    The microinjection of synthetic molecules, proteins, and nucleic acids into the cytosol of living cells is a powerful technique in cell biology. However, the insertion of a glass micropipette into the cell is a potentially damaging event, which presents significant problems, especially for small mammalian cells (spherical diameter = 2-15 micron), especially if they are only loosely adherent. The current technique is therefore limited to cells that are both sufficiently large or robust and fir...

  4. Niobium doped lanthanum calcium ferrite perovskite as a novel electrode material for symmetrical solid oxide fuel cells

    Science.gov (United States)

    Kong, Xiaowei; Zhou, Xiaoliang; Tian, Yu; Wu, Xiaoyan; Zhang, Jun; Zuo, Wei

    2016-09-01

    Development of cost-effective and efficient electrochemical catalysts for the fuel cells electrode is of prime importance to emerging renewable energy technologies. Here, we report for the first time the novel La0.9Ca0.1Fe0.9Nb0.1O3-δ (LCFNb) perovskite with good potentiality for the electrode material of the symmetrical solid oxide fuel cells (SSOFC). The Sc0.2Zr0.8O2-δ (SSZ) electrolyte supported symmetrical cells with impregnated LCFNb and LCFNb/SDC (Ce0.8Sm0.2O2-δ) electrodes achieve relatively high power outputs with maximum power densities (MPDs) reaching up to 392 and 528.6 mW cm-2 at 850 °C in dry H2, respectively, indicating the excellent electro-catalytic activity of LCFNb towards both hydrogen oxidation and oxygen reduction. Besides, the MPDs of the symmetrical cells with LCFNb/SDC composite electrodes in CO and syngas (CO: H2 = 1:1) are almost identical to those in H2, implying that LCFNb material has similar catalytic activities to carbon monoxide compared with hydrogen. High durability in both H2, CO and syngas during the short term stability tests for 50 h are also obtained, showing desirable structure stability, and carbon deposition resistance of LCFNb based electrodes. The present results indicate that the LCFNb perovskite with remarkable cell performance is a promising electrode material for symmetrical SOFCs.

  5. Mechanism of initial attachment of cells derived from human bone to commonly used prosthetic materials during cell culture.

    Science.gov (United States)

    Howlett, C R; Evans, M D; Walsh, W R; Johnson, G; Steele, J G

    1994-02-01

    The suitability of polymeric biomaterials as surfaces for the attachment and growth of cells has often been investigated in cell culture. In this study the contribution that serum fibronectin (Fn) or vitronectin (Vn) make to the attachment and spreading of cells cultured from explanted human bone (bone-derived cells) during the first 90 min of culture was determined for metallic and ceramic surfaces. The requirement for Fn or Vn for attachment and spreading of bone-derived cells onto stainless steel 316 (SS), titanium (Ti) and alumina (Al2O3) and to polyethyleneterephthalate (PET) was directly tested by selective removal of Fn or Vn from the serum prior to addition to the culture medium. Attachment and spreading of bone-derived cells onto SS, Ti and Al2O3 surfaces were reduced by 73-83% when the cells were seeded in medium containing serum from which the Vn had been removed. Cell attachment and spreading on these surfaces when seeded in medium containing Fn-depleted serum (which contained Vn) were not reduced to the same extent as in the medium containing Vn-depleted serum. The bone-derived cells failed to attach to the surfaces to the same extent when seeded in medium containing serum depleted of both Vn and Fn. Our results show that for human bone-derived cells, the attachment and spreading of cells onto SS, Ti and Al2O3 as well as PET during the first 90 min of a cell culture attachment assay are a function of adsorption of serum Vn onto the surface. PMID:7515290

  6. A monoclonal antibody (OPT1 to T cells which is available for paraffin-embedded materials.

    Directory of Open Access Journals (Sweden)

    Mukuzono,Hiroshi

    1991-06-01

    Full Text Available A monoclonal antibody (MAb, OPT1, reactive with T cells in formalin-fixed, paraffin-embedded tissue sections, has been identified through immunization with activated T cells from peripheral blood lymphocytes (PBL. The antibody is an IgG1 antibody as demonstrated by the Ouchterlony technique. By cytofluorometric analysis, almost all CD3+ lymphocytes and only a few CD20+ lymphocytes of peripheral blood expressed the OPT1 antigen. Nonhematolymphoid cell lines were negative for OPT1 by the immunoperoxidase staining using acetone-fixed cell lines. On the contrary, peripheral T cells, cells of two T cell lines out of four and a part of the cells of one B cell line out of two were positive for OPT1. The immunoperoxidase staining of paraffin-embedded tissue sections revealed that most of lymphocytes in T cell areas of lymph nodes expressed OPT1 antigen. Some lymphocytes in both cortex and medulla of the thymus and erythroid precursors of the bone marrow were OPT1+. In the malignant lymphoma series, approximately 90% of T cell lymphomas and 6% of B cell lymphomas reacted with OPT1. None of the Reed-Sternberg cells nor Hodgkin cells in Hodgkin's disease were positive. Consequently, OPT1 may be useful for the diagnosis and study of malignant lymphomas and other related lesions.

  7. Application of Nanostructured Materials and Multi-junction Structure in Polymer Solar Cells

    KAUST Repository

    Gao, Yangqin

    2015-12-09

    With power conversion efficiency surpassing the 10% milestone for commercialization, photovoltaic technology based on solution-processable polymer solar cells (PSCs) provides a promising route towards a cost-efficient strategy to address the ever-increasing worldwide energy demands. However, to make PSCs successful, challenges such as insufficient light absorption, high maintenance costs, and relatively high production costs must be addressed. As solutions to some of these problems, the unique properties of nanostructured materials and complimentary light absorption in multi-junction device structure could prove to be highly beneficial. As a starting point, integrating nanostructure-based transparent self-cleaning surfaces in PSCs was investigated first. By controlling the length of the hydrothermally grown ZnO nanorods and covering their surface with a thin layer of chemical vapor-deposited SiO2, a highly transparent and UV-resistant superhydrophobic surface was constructed. Integrating the transparent superhydrophobic surface in a PSC shows minimal impact on the figure of merit of the PSC. To address the low mechanical durability of the transparent superhydrophobic surface based on SiO2-coated ZnO nanorods, a novel method inspired by the water condensation process was developed. This method involved directly growing hollow silica half-nanospheres on the substrate through the condensation of water in the presence of a silica precursor. Benefit from the decreased back scattering efficiency and increased light transport mean free path arise from the hollow nature, a transparent superhydrophobic surface was realized using submicrometer sized silica half-nanospheres. The decent mechanical property of silica and the “direct-grown” protocol are expected to impart improved mechanical durability to the transparent superhydrophobic surface. Regarding the application of multi-junction device structure in PSCs, homo multi-junction PSCs were constructed from an identical

  8. Penternary chalcogenides nanocrystals as catalytic materials for efficient counter electrodes in dye-synthesized solar cells

    Science.gov (United States)

    Özel, Faruk; Sarılmaz, Adem; İstanbullu, Bilal; Aljabour, Abdalaziz; Kuş, Mahmut; Sönmezoğlu, Savaş

    2016-01-01

    The penternary chalcogenides Cu2CoSn(SeS)4 and Cu2ZnSn(SeS)4 were successfully synthesized by hot-injection method, and employed as a catalytic materials for efficient counter electrodes in dye-synthesized solar cells (DSSCs). The structural, compositional, morphological and optical properties of these pentenary semiconductors were characterized by X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), energy-dispersive spectrometer (EDS) and ultraviolet-visible (UV–Vis) spectroscopy. The Cu2CoSn(SeS)4 and Cu2ZnSn(SeS)4 nanocrystals had a single crystalline, kesterite phase, adequate stoichiometric ratio, 18–25 nm particle sizes which are forming nanospheres, and band gap energy of 1.18 and 1.45 eV, respectively. Furthermore, the electrochemical impedance spectroscopy and cyclic voltammograms indicated that Cu2CoSn(SeS)4 nanocrystals as counter electrodes exhibited better electrocatalytic activity for the reduction of iodine/iodide electrolyte than that of Cu2ZnSn(SeS)4 nanocrystals and conventional platinum (Pt). The photovoltaic results demonstrated that DSSC with a Cu2CoSn(SeS)4 nanocrystals-based counter electrode achieved the best efficiency of 6.47%, which is higher than the same photoanode employing a Cu2ZnSn(SeS)4 nanocrystals (3.18%) and Pt (5.41%) counter electrodes. These promising results highlight the potential application of penternary chalcogen Cu2CoSn(SeS)4 nanocrystals in low-cost, high-efficiency, Pt-free DSSCs. PMID:27380957

  9. Penternary chalcogenides nanocrystals as catalytic materials for efficient counter electrodes in dye-synthesized solar cells

    Science.gov (United States)

    Özel, Faruk; Sarılmaz, Adem; Istanbullu, Bilal; Aljabour, Abdalaziz; Kuş, Mahmut; Sönmezoğlu, Savaş

    2016-07-01

    The penternary chalcogenides Cu2CoSn(SeS)4 and Cu2ZnSn(SeS)4 were successfully synthesized by hot-injection method, and employed as a catalytic materials for efficient counter electrodes in dye-synthesized solar cells (DSSCs). The structural, compositional, morphological and optical properties of these pentenary semiconductors were characterized by X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), energy-dispersive spectrometer (EDS) and ultraviolet-visible (UV–Vis) spectroscopy. The Cu2CoSn(SeS)4 and Cu2ZnSn(SeS)4 nanocrystals had a single crystalline, kesterite phase, adequate stoichiometric ratio, 18–25 nm particle sizes which are forming nanospheres, and band gap energy of 1.18 and 1.45 eV, respectively. Furthermore, the electrochemical impedance spectroscopy and cyclic voltammograms indicated that Cu2CoSn(SeS)4 nanocrystals as counter electrodes exhibited better electrocatalytic activity for the reduction of iodine/iodide electrolyte than that of Cu2ZnSn(SeS)4 nanocrystals and conventional platinum (Pt). The photovoltaic results demonstrated that DSSC with a Cu2CoSn(SeS)4 nanocrystals-based counter electrode achieved the best efficiency of 6.47%, which is higher than the same photoanode employing a Cu2ZnSn(SeS)4 nanocrystals (3.18%) and Pt (5.41%) counter electrodes. These promising results highlight the potential application of penternary chalcogen Cu2CoSn(SeS)4 nanocrystals in low-cost, high-efficiency, Pt-free DSSCs.

  10. Penternary chalcogenides nanocrystals as catalytic materials for efficient counter electrodes in dye-synthesized solar cells.

    Science.gov (United States)

    Özel, Faruk; Sarılmaz, Adem; İstanbullu, Bilal; Aljabour, Abdalaziz; Kuş, Mahmut; Sönmezoğlu, Savaş

    2016-01-01

    The penternary chalcogenides Cu2CoSn(SeS)4 and Cu2ZnSn(SeS)4 were successfully synthesized by hot-injection method, and employed as a catalytic materials for efficient counter electrodes in dye-synthesized solar cells (DSSCs). The structural, compositional, morphological and optical properties of these pentenary semiconductors were characterized by X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), energy-dispersive spectrometer (EDS) and ultraviolet-visible (UV-Vis) spectroscopy. The Cu2CoSn(SeS)4 and Cu2ZnSn(SeS)4 nanocrystals had a single crystalline, kesterite phase, adequate stoichiometric ratio, 18-25 nm particle sizes which are forming nanospheres, and band gap energy of 1.18 and 1.45 eV, respectively. Furthermore, the electrochemical impedance spectroscopy and cyclic voltammograms indicated that Cu2CoSn(SeS)4 nanocrystals as counter electrodes exhibited better electrocatalytic activity for the reduction of iodine/iodide electrolyte than that of Cu2ZnSn(SeS)4 nanocrystals and conventional platinum (Pt). The photovoltaic results demonstrated that DSSC with a Cu2CoSn(SeS)4 nanocrystals-based counter electrode achieved the best efficiency of 6.47%, which is higher than the same photoanode employing a Cu2ZnSn(SeS)4 nanocrystals (3.18%) and Pt (5.41%) counter electrodes. These promising results highlight the potential application of penternary chalcogen Cu2CoSn(SeS)4 nanocrystals in low-cost, high-efficiency, Pt-free DSSCs. PMID:27380957

  11. Neural stem cells could serve as a therapeutic material forage-related neurodegenerative diseases

    Institute of Scientific and Technical Information of China (English)

    Sarawut Suksuphew; Parinya Noisa

    2015-01-01

    Progressively loss of neural and glial cells is the keyevent that leads to nervous system dysfunctions anddiseases. Several neurodegenerative diseases, forinstance Alzheimer's disease, Parkinson's disease, andHuntington's disease, are associated to aging andsuggested to be a consequence of deficiency of neuralstem cell pool in the affected brain regions. Endogenousneural stem cells exist throughout life and are found inspecific niches of human brain. These neural stem cellsare responsible for the regeneration of new neurons torestore, in the normal circumstance, the functions of thebrain. Endogenous neural stem cells can be isolated,propagated, and, notably, differentiated to most celltypes of the brain. On the other hand, other types ofstem cells, such as mesenchymal stem cells, embryonicstem cells, and induced pluripotent stem cells can alsoserve as a source for neural stem cell production, thathold a great promise for regeneration of the brain. Thereplacement of neural stem cells, either endogenousor stem cell-derived neural stem cells, into impairedbrain is highly expected as a possible therapeutic meanfor neurodegenerative diseases. In this review, clinicalfeatures and current routinely treatments of agerelatedneurodegenerative diseases are documented.Noteworthy, we presented the promising evidence ofneural stem cells and their derivatives in curing suchdiseases, together with the remaining challenges toachieve the best outcome for patients.

  12. EDITORIAL: Nanotechnology at the interface of cell biology, materials science and medicine Nanotechnology at the interface of cell biology, materials science and medicine

    Science.gov (United States)

    Engel, Andreas; Miles, Mervyn

    2008-09-01

    The atomic force microscope (AFM) and related scanning probe microscopes have become resourceful tools to study cells, supramolecular assemblies and single biomolecules, because they allow investigations of such structures in native environments. Quantitative information has been gathered about the surface structure of membrane proteins to lateral and vertical resolutions of 0.5 nm and 0.1 nm, respectively, about the forces that keep protein-protein and protein-nucleic acid assemblies together as well as single proteins in their native conformation, and about the nanomechanical properties of cells in health and disease. Such progress has been achieved mainly because of constant development of AFM instrumentation and sample preparation methods. This special issue of Nanotechnology presents papers from leading laboratories in the field of nanobiology, covering a wide range of topics in the form of original and novel scientific contributions. It addresses achievements in instrumentation, sample preparation, automation and in biological applications. These papers document the creativity and persistence of researchers pursuing the goal to unravel the structure and dynamics of cells, supramolecuar structures and single biomolecules at work. Improved cantilever sensors, novel optical probes, and quantitative data on supports for electrochemical experiments open new avenues for characterizing biological nanomachines down to the single molecule. Comparative measurements of healthy and metastatic cells promise new methods for early detection of tumors, and possible assessments of drug efficacy. High-speed AFMs document possibilities to monitor crystal growth and to observe large structures at video rate. A wealth of information on amyloid-type fibers as well as on membrane proteins has been gathered by single molecule force spectroscopy—a technology now being automated for large-scale data collection. With the progress of basic research and a strong industry supporting

  13. Contrast Materials

    Science.gov (United States)

    ... adverse reaction, you should tell your doctor about: allergies to contrast materials, food, drugs, dyes, preservatives, or animals medications ... These include: previous adverse reactions to iodine-based contrast materials history of ... disease dehydration sickle cell anemia , polycythemia and ...

  14. A review on solar cells from Si-single crystals to porous materials and quantum dots

    OpenAIRE

    Badawy, Waheed A.

    2013-01-01

    Solar energy conversion to electricity through photovoltaics or to useful fuel through photoelectrochemical cells was still a main task for research groups and developments sectors. In this article we are reviewing the development of the different generations of solar cells. The fabrication of solar cells has passed through a large number of improvement steps considering the technological and economic aspects. The first generation solar cells were based on Si wafers, mainly single crystals. P...

  15. INTEGRATION OF CELL FORMATION AND LAYOUT DESIGN IN THE UNIDIRECTIONAL LOOP MATERIAL HANDLING ENVIRONMENT

    Institute of Scientific and Technical Information of China (English)

    Lei Deming; Wu Zhiming

    2005-01-01

    A two-phase approach is proposed to deal with the integration problem in the loop layout.Tabu search is applied to cell construction in phase 1 to minimize the inter-cell flow, and the heuristic for layout design is used as phase 2 to optimize the sum ofintra-cell and inter-cell transportation cost.The final computational results demonstrate the validation of the two-phase approach.

  16. Sintesis dan Karakterisasi Membran untuk Proses Ultrafiltrasi

    Directory of Open Access Journals (Sweden)

    Sri Aprilia

    2011-12-01

    Full Text Available Asymmetric ultrafiltration (UF membranes were prepared from three kinds of polymer namely polyacrilonitryle (PAN, polysufone (PS, and cellulose acetate (CA by phase inversion method. Water was used as non-solvent. These membranes were charachterized for ultrafiltration membranes i.e measurement of solvent permeability (Lp, Molecular Weight Cut Off membranes (MWCO with various molecular weight of solute dekstran, and morphology of the membrane by Scanning Electron Microscopy (SEM. SEM analysis includes surface area and cross section area. Membranes with polymer low concentration 10% as PAN-1, PS-1 and CA-1 have the larger Lp from PAN-2, PS-2, and CA-2 that have concentration 15%  for the same type of polymer. These occur because of the larger pore membrane than high concentration of polymer. SEM analysis showed a homogeneous distribution in the surface membrane and pore of membran like sponge structure from cross section area. Membranes CA-1, CA-2, FS-1 and FS-2 have Molecular Weight Cut off (MWCO for the solute dextran 40000 Da. For PS-2 and PS-2 membranes have MWCO of dextran above 20000 Da. Keywords: ultrafiltration membrane, solvent permeability coeficient, MWCO, membrane morphology

  17. New π-Conjugated Materials Based on Furylenevinylene Candidate for Organic Solar Cells Application: A DFT Study

    Directory of Open Access Journals (Sweden)

    El Alamy Aziz

    2015-12-01

    Full Text Available The specific properties of organic-conjugated molecules and polymers are of great importance since they have become the most promising materials for the optoelectronic device technology such as solar cells. The use of low band gap materials is a viable method for better harvesting of the solar spectrum and increasing its efficiency. The control of the parameters of these materials is a research issue of ongoing interest. In this work, a quantum chemical investigation was performed to explore the optical and electronic properties of a series of different compounds based on furylenevinylene. Different electron side groups were introduced to investigate their effects on the electronic structure. The theoretical knowledge of the highest occupied molecular orbital (HOMO and lowest unoccupied molecular orbital (LUMO energy levels of the components is basic in studying organic solar cells; so the HOMO, LUMO, Gap energy and open circuit voltage (Voc of the studied compounds have been calculated and reported. These properties suggest that these materials behave as good candidate for organic solar cells. DOI: http://dx.doi.org/10.17807/orbital.v7i4.763 

  18. In vitro degradation and cell response of calcium carbonate composite ceramic in comparison with other synthetic bone substitute materials

    International Nuclear Information System (INIS)

    The robust calcium carbonate composite ceramics (CC/PG) can be acquired by fast sintering calcium carbonate at a low temperature (650 °C) using a biocompatible, degradable phosphate-based glass (PG) as sintering agent. In the present study, the in vitro degradation and cell response of CC/PG were assessed and compared with 4 synthetic bone substitute materials, calcium carbonate ceramic (CC), PG, hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) ceramics. The degradation rates in decreasing order were as follows: PG, CC, CC/PG, β-TCP, and HA. The proliferation of rat bone mesenchymal stem cells (rMSCs) cultured on the CC/PG was comparable with that on CC and PG, but inferior to HA and β-TCP. The alkaline phosphatase (ALP) activity of rMSCs on CC/PG was lower than PG, comparable with β-TCP, but higher than HA. The rMSCs on CC/PG and PG had enhanced gene expression in specific osteogenic markers, respectively. Compared to HA and β-TCP, the rMSCs on the CC/PG expressed relatively lower level of collagen I and runt-related transcription factor 2, but showed more considerable expression of osteopontin. Although CC, PG, HA, and β-TCP possessed impressive performances in some specific aspects, they faced extant intrinsic drawbacks in either degradation rate or mechanical strength. Based on considerable compressive strength, moderate degradation rate, good cell response, and being free of obvious shortcoming, the CC/PG is promising as another choice for bone substitute materials. - Highlights: • A calcium carbonate composite ceramic (CC/PG) was acquired. • The in vitro degradation and cell response of CC/PG were compared to 4 materials. • The CC/PG showed moderate degradation rate. • The CC/PG exhibited good cell response. • The CC/PG was free of obvious drawback compared to other materials

  19. In vitro degradation and cell response of calcium carbonate composite ceramic in comparison with other synthetic bone substitute materials

    Energy Technology Data Exchange (ETDEWEB)

    He, Fupo [Department of Biomedical Engineering, School of Basic Sciences, Guangzhou Medical University, Guangzhou 510182 (China); Zhang, Jing [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Yang, Fanwen; Zhu, Jixiang; Tian, Xiumei [Department of Biomedical Engineering, School of Basic Sciences, Guangzhou Medical University, Guangzhou 510182 (China); Chen, Xiaoming, E-mail: xmchenw@126.com [Department of Biomedical Engineering, School of Basic Sciences, Guangzhou Medical University, Guangzhou 510182 (China)

    2015-05-01

    The robust calcium carbonate composite ceramics (CC/PG) can be acquired by fast sintering calcium carbonate at a low temperature (650 °C) using a biocompatible, degradable phosphate-based glass (PG) as sintering agent. In the present study, the in vitro degradation and cell response of CC/PG were assessed and compared with 4 synthetic bone substitute materials, calcium carbonate ceramic (CC), PG, hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) ceramics. The degradation rates in decreasing order were as follows: PG, CC, CC/PG, β-TCP, and HA. The proliferation of rat bone mesenchymal stem cells (rMSCs) cultured on the CC/PG was comparable with that on CC and PG, but inferior to HA and β-TCP. The alkaline phosphatase (ALP) activity of rMSCs on CC/PG was lower than PG, comparable with β-TCP, but higher than HA. The rMSCs on CC/PG and PG had enhanced gene expression in specific osteogenic markers, respectively. Compared to HA and β-TCP, the rMSCs on the CC/PG expressed relatively lower level of collagen I and runt-related transcription factor 2, but showed more considerable expression of osteopontin. Although CC, PG, HA, and β-TCP possessed impressive performances in some specific aspects, they faced extant intrinsic drawbacks in either degradation rate or mechanical strength. Based on considerable compressive strength, moderate degradation rate, good cell response, and being free of obvious shortcoming, the CC/PG is promising as another choice for bone substitute materials. - Highlights: • A calcium carbonate composite ceramic (CC/PG) was acquired. • The in vitro degradation and cell response of CC/PG were compared to 4 materials. • The CC/PG showed moderate degradation rate. • The CC/PG exhibited good cell response. • The CC/PG was free of obvious drawback compared to other materials.

  20. Method and apparatus for in-cell vacuuming of radiologically contaminated materials

    International Nuclear Information System (INIS)

    This patent describes a vacuum system having a vacuum source for collecting radiologically contaminated material for disposal, comprising: an inlet nozzle for collecting the material; a cyclone separator connected to the inlet nozzle to receive the material. The cyclone separator has a material discharge and an air flow discharge; a product container positioned at the material discharge for receiving material discharged from the cyclone separator. The product container is transparent for allowing observation of a level of material collected; a first prefilter downstream of the air flow discharge for filtering air from the air flow discharge; a second prefilter connected between the vacuum source and the first prefilter for filtering air from the first prefilter. The second prefilter has means for visually observing the air flow in the second prefilter; means for monitoring a pressure drop across the first prefilter; and means for supporting the product container against the material discharge during operation and for facilitating removal of the product container from the material discharge for disposal of the material

  1. Application of the photoreflectance technique to the characterization of quantum dot intermediate band materials for solar cells

    International Nuclear Information System (INIS)

    Intermediate band materials rely on the creation of a new electronic band within the bandgap of a conventional semiconductor that is isolated from the conduction and valence band by a true zero density of states. Due to the presence of the intermediate band, a solar cell manufactured using these materials is capable of producing additional photocurrent, thanks to the absorption of photons with energy lower than the conventional bandgap. In this respect, the characterization of these materials by suitable techniques becomes a key element in the development of the new photovoltaic devices called intermediate band solar cells. The technique of photoreflectance is particularly suited to this purpose because it is contact-less and allows the characterization of the material without the need of actually manufacturing a complete device. Using room temperature photoreflectance we have analyzed intermediate band materials based on quantum dots and have been able to identify the energy levels involved. Also, from the photoreflectance data we have demonstrated the overlap of the wave-functions defined by the quantum dots

  2. Characterisation of proton conducting oxide materials for use in reverse water gas shift catalysis and solid oxide fuel cells

    OpenAIRE

    De A. L. Viana, Hermenegildo

    2007-01-01

    This study concerned the preparation, characterisation and evaluation of different proton conductors for the Reverse Water Gas Shift Reaction (RWGS) and their evaluation as electrolytes for Solid Oxide Fuel Cells (SOFC) under H₂ and O₂. Materials with both catalytic and conductive properties are of a great interest, as their use in electrocatalytical systems may be very important. Sr₃CaZr₀.₅Ta₁.₅O₈.₇₅ (SCZT), BaCe₀.₉Y₀.₁O₂.₉₅ (BCY10) and Ba₃Ca₁.₁₈Nb₁.₈₂O₈.₇₃ (BCN18), were the initial material...

  3. Asymmetric bioreduction of acetophenones by Baker's yeast and its cell-free extract encapsulated in sol-gel silica materials

    Science.gov (United States)

    Kato, Katsuya; Nakamura, Hitomi; Nakanishi, Kazuma

    2014-02-01

    Baker's yeast (BY) encapsulated in silica materials was synthesized using a yeast cell suspension and its cell-free extract during a sol-gel reaction of tetramethoxysilane with nitric acid as a catalyst. The synthesized samples were fully characterized using various methods, such as scanning electron microscopy, nitrogen adsorption-desorption, Fourier transform infrared spectroscopy, thermogravimetry, and differential thermal analysis. The BY cells were easily encapsulated inside silica-gel networks, and the ratio of the cells in the silica gel was approximately 75 wt%, which indicated that a large volume of BY was trapped with a small amount of silica. The enzyme activity (asymmetric reduction of prochiral ketones) of BY and its cell-free extract encapsulated in silica gel was investigated in detail. The activities and enantioselectivities of free and encapsulated BY were similar to those of acetophenone and its fluorine derivatives, which indicated that the conformation structure of BY enzymes inside silica-gel networks did not change. In addition, the encapsulated BY exhibited considerably better solvent (methanol) stability and recyclability compared to free BY solution. We expect that the development of BY encapsulated in sol-gel silica materials will significantly impact the industrial-scale advancement of high-efficiency and low-cost biocatalysts for the synthesis of valuable chiral alcohols.

  4. Asymmetric bioreduction of acetophenones by Baker's yeast and its cell-free extract encapsulated in sol–gel silica materials

    International Nuclear Information System (INIS)

    Baker's yeast (BY) encapsulated in silica materials was synthesized using a yeast cell suspension and its cell-free extract during a sol–gel reaction of tetramethoxysilane with nitric acid as a catalyst. The synthesized samples were fully characterized using various methods, such as scanning electron microscopy, nitrogen adsorption–desorption, Fourier transform infrared spectroscopy, thermogravimetry, and differential thermal analysis. The BY cells were easily encapsulated inside silica-gel networks, and the ratio of the cells in the silica gel was approximately 75 wt%, which indicated that a large volume of BY was trapped with a small amount of silica. The enzyme activity (asymmetric reduction of prochiral ketones) of BY and its cell-free extract encapsulated in silica gel was investigated in detail. The activities and enantioselectivities of free and encapsulated BY were similar to those of acetophenone and its fluorine derivatives, which indicated that the conformation structure of BY enzymes inside silica-gel networks did not change. In addition, the encapsulated BY exhibited considerably better solvent (methanol) stability and recyclability compared to free BY solution. We expect that the development of BY encapsulated in sol–gel silica materials will significantly impact the industrial-scale advancement of high-efficiency and low-cost biocatalysts for the synthesis of valuable chiral alcohols.

  5. Facile Synthesis and High performance of a New Carbazole-Based Hole Transporting Material for Hybrid Perovskite Solar Cells

    KAUST Repository

    Wang, Hong

    2015-06-26

    Perovskite solar cells are very promising for practical applications owing to their rapidly rising power conversion efficiency and low cost of solution-based processing. 2,2’,7,7’-tetrakis-(N,N-di-p-methoxyphenylamine) 9,9’-spirobifluorene (Spiro-OMeTAD) is most widely used as hole transporting material (HTM) in perovskite solar cells. However, the tedious synthesis and high cost of Spiro-OMeTAD inhibit its commercial-scale application in the photovoltaic industry. In this article, we report a carbazole-based compound (R01) as a new HTM in efficient perovskite solar cells. R01 is synthesized via a facile route consisting of only two steps from inexpensive commercially available materials. Furthermore, R01 exhibits higher hole mobility and conductivity than the state-of-the-art Spiro-OMeTAD. Perovskite solar cells fabricated with R01 produce a power conversion efficiency of 12.03%, comparable to that obtained in devices using Spiro-OMeTAD in this study. Our findings underscore R01 as a highly promising HTM with high performance, and its facile synthesis and low cost may facilitate the large-scale applications of perovskite solar cells.

  6. A Comparative Study on Root Canal Repair Materials: A Cytocompatibility Assessment in L929 and MG63 Cells

    Directory of Open Access Journals (Sweden)

    Yuqing Jiang

    2014-01-01

    Full Text Available Cytocompatibility of repair materials plays a significant role in the success of root canal repair. We conducted a comparative study on the cytocompatibility among iRoot BP Plus, iRoot FS, ProRoot MTA, and Super-EBA in L929 cells and MG63 cells. The results revealed that iRoot FS was able to completely solidify within 1 hour. iRoot BP Plus required 7-day incubation, which was much longer than expected (2 hours, to completely set. ProRoot MTA and Super-EBA exhibited a similar setting duration of 12 hours. All the materials except Super-EBA possessed negligible in vitro cytotoxicity. iRoot FS had the best cell adhesion capacity in both L929 and MG63 cells. With rapid setting, negligible cytotoxicity, and enhanced cell adhesion capacity, iRoot FS demonstrated great potential in clinical applications. Future work should focus on longer-term in vitro cytocompatibility and an in vivo assessment.

  7. Multi-channel cell to irradiate the material specimens by electrons in the interior of the supercritical water convection loop

    International Nuclear Information System (INIS)

    The 1.2x1.5 m sized Supercritical Water Convection Loop with four-channel irradiation cell was created in KIPT. The stainless steel made plant opens the possibility to carry out simulation corrosion tests of candidate structural materials for Generation IV Supercritical Water-Cooled Reactors (SCWR) under irradiation. Specimens in water flow at 350...400 C, 23...25 MPa are irradiated by 10 MeV/10 kW electron beam of LPE-10 linear accelerator. The results of the four-channel cell application for 500 hours long irradiation Zr and Inconel samples are presented

  8. Corneal cell adhesion to contact lens hydrogel materials enhanced via tear film protein deposition.

    Directory of Open Access Journals (Sweden)

    Claire M Elkins

    Full Text Available Tear film protein deposition on contact lens hydrogels has been well characterized from the perspective of bacterial adhesion and viability. However, the effect of protein deposition on lens interactions with the corneal epithelium remains largely unexplored. The current study employs a live cell rheometer to quantify human corneal epithelial cell adhesion to soft contact lenses fouled with the tear film protein lysozyme. PureVision balafilcon A and AirOptix lotrafilcon B lenses were soaked for five days in either phosphate buffered saline (PBS, borate buffered saline (BBS, or Sensitive Eyes Plus Saline Solution (Sensitive Eyes, either pure or in the presence of lysozyme. Treated contact lenses were then contacted to a live monolayer of corneal epithelial cells for two hours, after which the contact lens was sheared laterally. The apparent cell monolayer relaxation modulus was then used to quantify the extent of cell adhesion to the contact lens surface. For both lens types, lysozyme increased corneal cell adhesion to the contact lens, with the apparent cell monolayer relaxation modulus increasing up to an order of magnitude in the presence of protein. The magnitude of this increase depended on the identity of the soaking solution: lenses soaked in borate-buffered solutions (BBS, Sensitive Eyes exhibited a much greater increase in cell attachment upon protein addition than those soaked in PBS. Significantly, all measurements were conducted while subjecting the cells to moderate surface pressures and shear rates, similar to those experienced by corneal cells in vivo.

  9. On-Chip Single-Cell Lysis for Extracting Intracellular Material

    Science.gov (United States)

    Ikeda, Norifumi; Tanaka, Nobuaki; Yanagida, Yasuko; Hatsuzawa, Takeshi

    2007-09-01

    A newly designed microfluidic chip with a pinched-channel structure and two pairs of electrodes has been developed to enable easier single-cell capture and lysis. The function of the chip was evaluated by introducing zucchini protoplast cells into the channel. In the first experiment, we attempted to break a cell using the through force of a triangular pinched structure via electroosmotic flow generated by outer electrodes. The pinched structure appeared to break the cell without applying the electric field to the cell directly; however, in this case, the breakable size of the cell was limited by the width of the pinched structure. The next attempt was to break cells regardless of their sizes using a pair of inner electrodes located under the pinched structure. The inner electrodes generated a gradient electric field around the captured cell by applying an alternative voltage to the electrodes. Captured cells with a diameter from 40 to 85 μm could be broken using the inner electrodes with a trapezoidal pinched structure, and the cells were successfully broken at 10 Vpp or less at a frequency of 1 MHz.

  10. Thermal Characteristics of Multilayer Insulation Materials for Flexible Thin-Film Solar Cell Array of Stratospheric Airship

    Directory of Open Access Journals (Sweden)

    Kangwen Sun

    2014-01-01

    Full Text Available Flexible thin-film solar cell is an efficient energy system on the surface of stratospheric airship for utilizing the solar energy. In order to ensure the normal operation of airship platform, the thermal control problem between the flexible thin-film solar cell and the airship envelope should be properly resolved. In this paper, a multilayer insulation material (MLI is developed first, and low temperature environment test is carried out to verify the insulation effect of MLI. Then, a thermal heat transfer model of flexible thin-film solar cell and MLI is proposed, and the equivalent thermal conductivity coefficients of flexible thin-film solar cell and Nomex honeycomb are calculated based on the environment test and the temperature profile of flexible thin-film solar cell versus each layer of MLI. Finally, FLUENT is used for modeling and simulation analysis on the flexible thin-film solar cell and MLI, and the simulation results agree well with the experimental data, which validate the correctness of the proposed heat transfer model of MLI. In some way, our study can provide helpful support for further engineering applications of flexible thin-film solar cell.

  11. Fuel cells science and engineering. Materials, processes, systems and technology. Vol. 2

    Energy Technology Data Exchange (ETDEWEB)

    Stolten, Detlef; Emonts, Bernd (eds.) [Forschungszentrum Juelich GmbH (DE). Inst. fuer Energieforschung (IEF), Brennstoffzellen (IEF-3)

    2012-07-01

    The second volume is divided in four parts and 19 chapters. It is structured as follows: PART V: Modeling and Simulation. Chapter 23: Messages from Analytical Modeling of Fuel Cells (Andrei Kulikovsky); 24: Stochastic Modeling of Fuel-Cell Components (Ralf Thiedmann, Gerd Gaiselmann, Werner Lehnert and Volker Schmidt); 25: Computational Fluid Dynamic Simulation Using Supercomputer Calculation Capacity (Ralf Peters and Florian Scharf); 26 Modeling Solid Oxide Fuel Cells from the Macroscale to the Nanoscale (Emily M. Ryan and Mohammad A. Khaleel); 27: Numerical Modeling of the Thermomechanically Induced Stress in Solid Oxide Fuel Cells (Murat Peksen); 28: Modeling of Molten Carbonate Fuel Cells (Peter Heidebrecht, Silvia Piewek and Kai Sundmacher); Chapter 29: High-Temperature Polymer Electrolyte Fuel-Cell Modeling (Uwe Reimer); Chapter 30: Modeling of Polymer Electrolyte Membrane Fuel-Cell Components (Yun Wang and Ken S. Chen); 31: Modeling of Polymer Electrolyte Membrane Fuel Cells and Stacks (Yun Wang and Ken S. Chen). PART VI: Balance of Plant Design and Components. Chapter 32: Principles of Systems Engineering (Ludger Blum, Ralf Peters and Remzi Can Samsun); 33: System Technology for Solid Oxide Fuel Cells (Nguyen Q. Minh); 34: Desulfurization for Fuel-Cell Systems (Joachim Pasel and Ralf Peters); 35: Design Criteria and Components for Fuel Cell Powertrains (Lutz Eckstein and Bruno Gnoerich); 36: Hybridization for Fuel Cells (Joerg Wilhelm). PART VII: Systems Verification and Market Introduction. Chapter 37: Off-Grid Power Supply and Premium Power Generation (Kerry-Ann Adamson); 38: Demonstration Projects and Market Introduction (Kristin Deason). PART VIII: Knowledge Distribution and Public Awareness. Chapter 39: A Sustainable Framework for International Collaboration: the IEA HIA and Its Strategic Plan for 2009-2015 (Mary-Rose de Valladares); 40: Overview of Fuel Cell and Hydrogen Organizations and Initiatives Worldwide (Bernd Emonts) 41: Contributions for

  12. Corrosion phenomena of alloys and electrode materials in molten carbonate fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Biedenkopf, P. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Werkstoffe und Verfahren der Energietechnik; Bischoff, M.M. [MTU-Friedrichshafen GmbH, - Neue Technologien - ZEB -, Muenchen (Germany); Wochner, T. [MTU-Friedrichshafen GmbH, Abt. TQZ, Friedrichshafen (Germany)

    2000-05-01

    The corrosion behavior of different alloys and the electrical conductivity of the growing corrosion scales was investigated under simulated and real molten carbonate fuel cell conditions. The corrosion of the usually used NiO cathode material was also investigated. In several exposure tests in oxidizing atmospheres, the FeCrMnNi steel 1.3965 showed a higher corrosion resistance to the aggressive carbonate media than the FeCrNi alloy 1.4404 (SS316L). This superior corrosion resistance is explained by the formation of a mixed (Fe,Ni,Mn){sub x}Cr{sub 3-x}O{sub 4} spinel layer, which reduces the outward diffusion of iron ions more than the mixed (Fe,Ni)Cr{sub 2}O{sub 4} spinel formed on austenitic FeCrNi steels. Oxide debris, which spalls off the current collectors, was investigated by XRD. The corrosion scales spalled off mainly at the curved area of the current collector and not at the cathode/current collector interface. The debris was strongly magnetic and consisted of several, in some cases lithiated iron oxides, whereby {alpha}-Fe{sub 2}O{sub 3} (hematite), {gamma}-Fe{sub 2}O{sub 3} (maghemite) and Fe{sub 3}O{sub 4} (magnetite) formed most of the debris. The investigations of the electrical conductivity of the corrosion scales have shown that the electrical conductivity is limited by the inner, Cr-containing oxide of the multi-layered corrosion scale. Cr-rich alloys which contain more than 20 wt.% Cr showed extremely high ohmic resistance of the corrosion scale, much higher than that of alloys containing less than 20 wt.% Cr due to the formation of highly conductive mixed spinel layers. Small additions of Al in the alloy increased the ohmic resistance of the corrosion scale by many orders of magnitude. Corrosion tests in the fuel environment showed, that common uncoated stainless steels are not suitable for the use as anodic current collectors.

  13. A Mismatch Between Patient Education Materials About Sickle Cell Disease and the Literacy Level of Their Intended Audience

    Science.gov (United States)

    Ng, Jared; Vitzthum, Kelly; Rudd, Rima

    2016-01-01

    Introduction Despite the first goal of the 2010 National Action Plan to Improve Health Literacy, the literacy demands of much health information exceeds the reading skills of most US adults. The objective of this study was to assess the health literacy level of publicly available patient education materials for people with sickle cell disease (SCD). Methods We used 5 validated tools to evaluate 9 print and 4 online patient education materials: the simple measure of gobbledygook (SMOG) to assess reading grade level, the Peter Mosenthal and Irwin Kirsch readability formula (PMOSE/IKIRSCH) to assess structure and density, the Patient Education Materials Assessment Tool (PEMAT) to assess actionability (how well readers will know what to do after reading the material) and understandability, the Centers for Disease Control and Prevention’s (CDC’s) Clear Communication Index (Index) to obtain a comprehensive literacy demand score, and the Printed Cancer Education Materials for African Americans Cultural Sensitivity Assessment Tool. Results Materials’ scores reflected high reading levels ranging from 8th grade to 12th grade, appropriate (low) structural demand, and low actionability relative to understandability. CDC suggests that an appropriate Index score should fall in or above the 90th percentile. The scores yielded by materials evaluated in this assessment ranged from the 44th to the 76th percentiles. Eight of the 13 materials scored within the acceptable range for cultural sensitivity. Conclusion Reading levels of available patient education materials exceed the documented average literacy level of the US adult population. Health literacy demands should be a key consideration in the revision and development of patient education materials for people with SCD. PMID:27172259

  14. Large scale industrialized cell expansion: producing the critical raw material for biofabrication processes.

    Science.gov (United States)

    Kumar, Arun; Starly, Binil

    2015-12-01

    Cellular biomanufacturing technologies are a critical link to the successful application of cell and scaffold based regenerative therapies, organs-on-chip devices, disease models and any products with living cells contained in them. How do we achieve production level quantities of the key ingredient-'the living cells' for all biofabrication processes, including bioprinting and biopatterning? We review key cell expansion based bioreactor operating principles and how 3D culture will play an important role in achieving production quantities of billions to even trillions of anchorage dependent cells. Furthermore, we highlight some of the challenges in the field of cellular biomanufacturing that must be addressed to achieve desired cellular yields while adhering to the key pillars of good manufacturing practices-safety, purity, stability, potency and identity. Biofabrication technologies are uniquely positioned to provide improved 3D culture surfaces for the industrialized production of living cells. PMID:26539629

  15. Block copolymer based composition and morphology control in nanostructured hybrid materials for energy conversion and storage: solar cells, batteries, and fuel cells

    KAUST Repository

    Orilall, M. Christopher

    2011-01-01

    The development of energy conversion and storage devices is at the forefront of research geared towards a sustainable future. However, there are numerous issues that prevent the widespread use of these technologies including cost, performance and durability. These limitations can be directly related to the materials used. In particular, the design and fabrication of nanostructured hybrid materials is expected to provide breakthroughs for the advancement of these technologies. This tutorial review will highlight block copolymers as an emerging and powerful yet affordable tool to structure-direct such nanomaterials with precise control over structural dimensions, composition and spatial arrangement of materials in composites. After providing an introduction to materials design and current limitations, the review will highlight some of the most recent examples of block copolymer structure-directed nanomaterials for photovoltaics, batteries and fuel cells. In each case insights are provided into the various underlying fundamental chemical, thermodynamic and kinetic formation principles enabling general and relatively inexpensive wet-polymer chemistry methodologies for the efficient creation of multiscale functional materials. Examples include nanostructured ceramics, ceramic-carbon composites, ceramic-carbon-metal composites and metals with morphologies ranging from hexagonally arranged cylinders to three-dimensional bi-continuous cubic networks. The review ends with an outlook towards the synthesis of multicomponent and hierarchical multifunctional hybrid materials with different nano-architectures from self-assembly of higher order blocked macromolecules which may ultimately pave the way for the further development of energy conversion and storage devices. © 2011 The Royal Society of Chemistry.

  16. Deposition of hole-transport materials in solid-state dye-sensitized solar cells by doctor-blading

    KAUST Repository

    Ding, I-Kang

    2010-07-01

    We report using doctor-blading to replace conventional spin coating for the deposition of the hole-transport material spiro-OMeTAD (2,20,7,70-tetrakis-(N, N-di-p-methoxyphenylamine)- 9,90-spirobifluorene) in solid-state dye-sensitized solar cells. Doctor-blading is a roll-to-roll compatible, large-area coating technique, is capable of achieving the same spiro-OMeTAD pore filling fraction as spin coating, and uses much less material. The average power conversion efficiency of solid-state dye-sensitized solar cells made from doctorblading is 3.0% for 2-lm thick films and 2.0% for 5-lm thick films, on par with devices made with spin coating. Directions to further improve the filling fraction are also suggested. © 2010 Elsevier B.V. All rights reserved.

  17. Polymer Solar Cells – Non Toxic Processing and Stable Polymer Photovoltaic Materials

    OpenAIRE

    Søndergaard, Roar; Krebs, Frederik C.

    2012-01-01

    The field of polymer solar cell has experienced enormous progress in the previous years, with efficiencies of small scale devices (~1 mm2) now exceeding 8%. However, if the polymer solar cell is to achieve success as a renewable energy resource, mass production of sufficiently stable and efficient cell must be achieved. For a continuous success it is therefore essential to transfer the accomplishments from the laboratory to large scale facilities for actual production. In order to do so, seve...

  18. Bulk and interfacial thermal transport in microstructural porous materials with application to fuel cells

    OpenAIRE

    Sadeghifar, Hamidreza

    2015-01-01

    The performance, reliability and durability of fuel cells are strongly influenced by the operating conditions, especially temperature and compression. Adequate thermal and water management of fuel cells requires knowledge of the thermal bulk and interfacial resistances of all involved components. The porous, brittle and anisotropic nature of most fuel cell components, together with the micro/nano-sized structures, has made it challenging to study their transport properties and thermal behavio...

  19. Interaction of human endothelial cells and nickel-titanium materials modified with silicon ions

    Energy Technology Data Exchange (ETDEWEB)

    Lotkov, Aleksandr I., E-mail: lotkov@ispms.tsc.ru; Kashin, Oleg A., E-mail: okashin@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Kudryavtseva, Yuliya A., E-mail: yulia-k1970@mail.ru; Antonova, Larisa V., E-mail: antonova.la@mail.ru; Matveeva, Vera G., E-mail: matveeva-vg@mail.ru; Sergeeva, Evgeniya A., E-mail: sergeewa.ew@yandex.ru [Research Institute for Complex Issues of Cardiovascular Diseases, Kemerovo, 650002 (Russian Federation); Kudryashov, Andrey N., E-mail: kudryashov@angioline.ru [Angioline Interventional Device Ltd, Novosibirsk, 630090 (Russian Federation)

    2015-10-27

    The paper studies the influence of chemical and phase compositions of NiTi surface layers modified with Si ions by plasma immersion implantation on their interaction with endothelial cells. It is shown that certain technological modes of Si ion implantation enhance the adhesion, proliferation, and viability of endothelial cells. It is found that the Si-modified NiTi surface is capable of stimulating the formation of capillary-like structures in the cell culture.

  20. Interaction of human endothelial cells and nickel-titanium materials modified with silicon ions

    Science.gov (United States)

    Lotkov, Aleksandr I.; Kashin, Oleg A.; Kudryavtseva, Yuliya A.; Antonova, Larisa V.; Kudryashov, Andrey N.; Matveeva, Vera G.; Sergeeva, Evgeniya A.

    2015-10-01

    The paper studies the influence of chemical and phase compositions of NiTi surface layers modified with Si ions by plasma immersion implantation on their interaction with endothelial cells. It is shown that certain technological modes of Si ion implantation enhance the adhesion, proliferation, and viability of endothelial cells. It is found that the Si-modified NiTi surface is capable of stimulating the formation of capillary-like structures in the cell culture.

  1. Interaction of human endothelial cells and nickel-titanium materials modified with silicon ions

    International Nuclear Information System (INIS)

    The paper studies the influence of chemical and phase compositions of NiTi surface layers modified with Si ions by plasma immersion implantation on their interaction with endothelial cells. It is shown that certain technological modes of Si ion implantation enhance the adhesion, proliferation, and viability of endothelial cells. It is found that the Si-modified NiTi surface is capable of stimulating the formation of capillary-like structures in the cell culture

  2. Compatibility of copper-electroplated cells with Metal Wrap Through module materials

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, I.J.; Geerligs, L.J.; Olson, C.L.; Goris, M.J.A.A. [ECN Solar Energy, Petten (Netherlands)

    2013-10-16

    As part of the European FP7 RandD project 'Cu-PV', the compatibility of copper-electroplated metal wrapthrough (MWT) cells with conductive adhesives has been investigated. The objectives of this project include to reduce, by the use of copper plating, the amount of silver utilized in cell manufacturing, and to demonstrate the compatibility of high-power n-type back-contact module technology with copper-plated cells. The overall goal is to reduce the impact on the environment of cell and module manufacture. MWT module technology as developed by ECN uses conductive adhesive to make the interconnection between cells and a conductive backsheet foil. These adhesives have been proved to result in very reliable modules in the case of cells with fired silver metallization. To determine the compatibility of conductive adhesive with copper-plated cells, component tests were performed, followed by the manufacture of modules with copperplated cells and conductive adhesive interconnections. Climate chamber testing of these modules showed that the adhesive is compatible with the copper-plated cells. The next steps include further optimization of the plating process and additional testing at the module level.

  3. Processing and Characterisation of Diatoms for Light Harvesting Materials in Solar Cells

    OpenAIRE

    Ottesen, Petter

    2011-01-01

    By applying a texture to the front surface of solar cells, less light may be reflected and the incoming light may be given a longer path length inside the solar cell causing a better light absorbance for the solar cell. The textured layer is today made by etching with an acidic etch with a large part hydrogen fluoride. In the future a more environmental approach for creating textured solar cells may be favoured. There are many ways of creating textured surfaces, one of them are by imprinting ...

  4. Wurtzite copper-zinc-tin sulfide as a superior counter electrode material for dye-sensitized solar cells

    Science.gov (United States)

    2013-01-01

    Wurtzite and kesterite Cu2ZnSnS4 (CZTS) nanocrystals were employed as counter electrode (CE) materials for dye-sensitized solar cells (DSSCs). Compared to kesterite CZTS, the wurtzite CZTS exhibited higher electrocatalytic activity for catalyzing reduction of iodide electrolyte and better conductivity. Accordingly, the DSSC with wurtzite CZTS CE generated higher power conversion efficiency (6.89%) than that of Pt (6.23%) and kesterite CZTS (4.89%) CEs. PMID:24191954

  5. Wurtzite copper-zinc-tin sulfide as a superior counter electrode material for dye-sensitized solar cells

    OpenAIRE

    Kong, Jun; Zhou, Zheng-Ji; Mei LI; Zhou, Wen-Hui; Yuan, Sheng-Jie; Yao, Rong-Yue; Zhao, Yang; Wu, Si-Xin

    2013-01-01

    Wurtzite and kesterite Cu2ZnSnS4 (CZTS) nanocrystals were employed as counter electrode (CE) materials for dye-sensitized solar cells (DSSCs). Compared to kesterite CZTS, the wurtzite CZTS exhibited higher electrocatalytic activity for catalyzing reduction of iodide electrolyte and better conductivity. Accordingly, the DSSC with wurtzite CZTS CE generated higher power conversion efficiency (6.89%) than that of Pt (6.23%) and kesterite CZTS (4.89%) CEs.

  6. Wurtzite copper-zinc-tin sulfide as a superior counter electrode material for dye-sensitized solar cells.

    Science.gov (United States)

    Kong, Jun; Zhou, Zheng-Ji; Li, Mei; Zhou, Wen-Hui; Yuan, Sheng-Jie; Yao, Rong-Yue; Zhao, Yang; Wu, Si-Xin

    2013-01-01

    Wurtzite and kesterite Cu2ZnSnS4 (CZTS) nanocrystals were employed as counter electrode (CE) materials for dye-sensitized solar cells (DSSCs). Compared to kesterite CZTS, the wurtzite CZTS exhibited higher electrocatalytic activity for catalyzing reduction of iodide electrolyte and better conductivity. Accordingly, the DSSC with wurtzite CZTS CE generated higher power conversion efficiency (6.89%) than that of Pt (6.23%) and kesterite CZTS (4.89%) CEs. PMID:24191954

  7. Preparing for new solar cells through integrated research: challenges in translating social robustness into the selection of materials

    OpenAIRE

    Åm, Heidrun; Sørensen, Knut Holtan

    2015-01-01

    Research policy and research councils increasingly demand responsible innovation and socially robust knowledge. But what does that imply? Theories say little about how to translate social robustness into practice. In this chapter, we report from an integrated project on solar cells where Ethical, Legal and Social Aspects (ELSA) oriented scholars interacted with material scientists. The aim of the project was twofold. First, to achieve social robustness in the selection of ma...

  8. Morphological engineering of TiO2 photoanode material for optimum performance in dye-sensitized solar cell

    Czech Academy of Sciences Publication Activity Database

    Zukalová, Markéta; Kavan, Ladislav; Zukal, Arnošt; Graetzel, M.

    Rhodos: NANO2012, 2012. -. [International Conference on Nanostructured Materials /11./. 26.08.2012-31.08.2012, Rhodes] R&D Projects: GA ČR(CZ) GAP108/12/0814; GA AV ČR IAA400400804; GA AV ČR KAN200100801 Institutional support: RVO:61388955 Keywords : TiO2 * electrochemistry * dye-sensitized solar cell Subject RIV: CG - Electrochemistry

  9. Pengaruh Preparasi Pasta dan Temperatur Annealing pada Dye-Sensitized Solar Cells (DSSC Berbasis Nanopartikel ZnO

    Directory of Open Access Journals (Sweden)

    Ahmad Syukron

    2013-09-01

    Full Text Available Telah difabrikan Dye-sensitized Solar Cell (DSSC berbasis nanopartikel ZnO dengan variasi metode preparasi pasta sesuai dengan Yonekawa dan Gratzel dan temperatur fabrikasi. Nanopartikel ZnO dibuat dengan metode kopresipitasi yaitu dengan mereaksikan prekursor Zinc Asetat dengan DEG (diethylene glycol. Prepararasi fotoelektroda ZnO dilakukan dengan memvariasikan komposisi pasta berdasarkan metode yang dilakukan oleh Gratzel dan Yonekawa untuk mendapatkan efisiensi yang besar. Selain itu, dilakukan variasi temperatur pada proses anil fotoelektroda. Fabrikasi DSSC menggunakan pewarna manggis sebagai pewarna alami. DSSC difabrikasi dalam bentuk struktur sandwich dengan menggunakan pasangan redoks I3-/I- dan elektroda pembanding platina/karbon. Hasil karakterisasi ZnO menunjukkan ZnO berdispersi tunggal dengan ukuran agregat dan partikel sebesar ~300nm dan 13,93 nm. Energi band gap yang dihasilkan dari nanopartikel ZnO adalah 3,29 eV. Berdasarkan karakteristik kurva I-V dan IPCE, diperoleh bahwa efisiensi terbaik berada pada suhu 200°C dengan menggunakan metode Yonekawa sebesar 0,11% dengan IPCE 0,0005%, FF 61,41%, Isc 2,79µA, Voc 232,4 mV.

  10. Honeycomb porous films as permeable scaffold materials for human embryonic stem cell-derived retinal pigment epithelium.

    Science.gov (United States)

    Calejo, Maria Teresa; Ilmarinen, Tanja; Jongprasitkul, Hatai; Skottman, Heli; Kellomäki, Minna

    2016-07-01

    Age-related macular degeneration (AMD) is a leading cause of blindness in developed countries, characterised by the degeneration of the retinal pigment epithelium (RPE), a pigmented cell monolayer that closely interacts with the photoreceptors. RPE transplantation is thus considered a very promising therapeutic option to treat this disease. In this work, porous honeycomb-like films are for the first time investigated as scaffold materials for human embryonic stem cell-derived retinal pigment epithelium (hESC-RPE). By changing the conditions during film preparation, it was possible to produce films with homogeneous pore distribution and adequate pore size (∼3-5 µm), that is large enough to ensure high permeability but small enough to enable cell adherence and spreading. A brief dip-coating procedure with collagen type IV enabled the homogeneous adsorption of the protein to the walls and bottom of pores, increasing the hydrophilicity of the surface. hESC-RPE adhered and proliferated on all the collagen-coated materials, regardless of small differences in pore size. The differentiation of hESC-RPE was confirmed by the detection of specific RPE protein markers. These results suggest that the porous honeycomb films can be promising candidates for hESC-RPE tissue engineering, importantly enabling the free flow of ions and molecules across the material. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1646-1656, 2016. PMID:26914698

  11. Comparison of the Influence of Phospholipid-Coated Porous Ti-6Al-4V Material on the Osteosarcoma Cell Line Saos-2 and Primary Human Bone Derived Cells

    Directory of Open Access Journals (Sweden)

    Axel Deing

    2016-03-01

    Full Text Available Biomaterial surface functionalization remains of great interest in the promotion of cell osteogenic induction. Previous studies highlighted the positive effects of porous Ti-6Al-4V and phospholipid coating on osteoblast differentiation and bone remodeling. Therefore, the first objective of this study was to evaluate the potential synergistic effects of material porosity and phospholipid coating. Primary human osteoblasts and Saos-2 cells were cultured on different Ti-6Al-4V specimens (mirror-like polished or porous specimens and were coated or not with 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE for three weeks or five weeks. Selected gene expressions (e.g., classical bone markers: alkaline phosphatase, osteocalcin, osteoprotegerin (OPG, receptor activator of nuclear factor kappa-β ligand (RANKL and runt-related transcription factor 2 were estimated in vitro. Furthermore, the expressions of osteocalcin and osteopontin were examined via fluorescent microscopy at five weeks (immunocytochemistry. Consequently, it was observed that phospholipid coating potentiates preferences for low and high porosities in Saos-2 and primary cells, respectively, at the gene and protein levels. Additionally, RANKL and OPG exhibited different gene expression patterns; primary cells showed dramatically increased RANKL expression, whereas OPG expression was decreased in the presence of POPE. A synergistic effect of increased porosity and phospholipid coating was observed in primary osteoblasts in bone remodeling. This study showed the advantage of primary cells over the standard bone cell model.

  12. NREL Develops High-Speed Scanner to Monitor Fuel Cell Material Defects

    Energy Technology Data Exchange (ETDEWEB)

    2015-09-01

    This highlight describes results of recent work in which polymer electrolyte membrane fuel cell electrodes with intentionally introduced known defects were imaged and analyzed using a fuel cell scanner recently developed at NREL. The highlight is being developed for the September 2015 Alliance S&T Board meeting.

  13. Thermocleavable Materials for Polymer Solar Cells with High Open Circuit Voltage-A Comparative Study

    DEFF Research Database (Denmark)

    Tromholt, Thomas; Gevorgyan, Suren; Jørgensen, Mikkel;

    2009-01-01

    The search for polymer solar cells giving a high open circuit voltage was conducted through a comparative study of four types of bulk-heterojunction solar cells employing different photoactive layers. As electron donors the thermo-cleavable polymer poly-(3-(2-methylhexyloxycarbonyl)dithiophene) (P3...

  14. In vitro mesenchymal stem cell response to a CO2 laser modified polymeric material.

    Science.gov (United States)

    Waugh, D G; Hussain, I; Lawrence, J; Smith, G C; Cosgrove, D; Toccaceli, C

    2016-10-01

    With an ageing world population it is becoming significantly apparent that there is a need to produce implants and platforms to manipulate stem cell growth on a pharmaceutical scale. This is needed to meet the socio-economic demands of many countries worldwide. This paper details one of the first ever studies in to the manipulation of stem cell growth on CO2 laser surface treated nylon 6,6 highlighting its potential as an inexpensive platform to manipulate stem cell growth on a pharmaceutical scale. Through CO2 laser surface treatment discrete changes to the surfaces were made. That is, the surface roughness of the nylon 6,6 was increased by up to 4.3μm, the contact angle was modulated by up to 5° and the surface oxygen content increased by up to 1atom %. Following mesenchymal stem cell growth on the laser treated samples, it was identified that CO2 laser surface treatment gave rise to an enhanced response with an increase in viable cell count of up to 60,000cells/ml when compared to the as-received sample. The effect of surface parameters modified by the CO2 laser surface treatment on the mesenchymal stem cell response is also discussed along with potential trends that could be identified to govern the mesenchymal stem cell response. PMID:27287173

  15. Serigraphy materialization of bi facial solar cells; Metalizacao serigrafica de celulas solares bifaciais

    Energy Technology Data Exchange (ETDEWEB)

    Moehlecke, Adriano; Zanesco, Izete; Mallmann, Ana P.; Eberhardt, Dario; Pereira, Gabriel F. [Pontificia Univ. Catolica do Rio Grande do Sul, Porto Alegre, RS (Brazil). Centro Brasileiro para Desenvolvimento da Energia Solar Fotovoltaica - CB-Solar]. E-mail: moehleck@pucrs.br

    2006-07-01

    This paper presents the low cost metallization process, based on serigraphy, for the fabrication of bifacial solar cells, optimizing the metallic patches project and the solar cell considering the serigraphic pastes, projected and manufactured a metallization mask, and implanted a screen-printer.

  16. Application of ATR-FTIR Spectroscopy to Compare the Cell Materials of Wood Decay Fungi with Wood Mould Fungi

    Directory of Open Access Journals (Sweden)

    Barun Shankar Gupta

    2015-01-01

    Full Text Available Wood fungi create vast damage among standing trees and all types of wood materials. The objectives of this study are to (a characterize the cell materials of two major wood decay fungi (Basidiomycota, namely, Trametes versicolor and Postia placenta, and (b compare the cell materials of decay fungi with four wood mould fungi (Ascomycota, namely, Aureobasidium pullulans, Alternaria alternata, Cladosporium cladosporioides, and Ulocladium atrum. Fourier transform infrared (FTIR spectroscopy is used to characterize the microbial cellular materials. The results showed that the IR bands for the fatty acid at ∼2900 cm−1 were different for the two-decay-fungi genre. Postia placenta shows more absorbance peaks at the fatty acid region. Band ratio indices for amide I and amide II from protein amino acids were higher for the mould fungi (Ascomycota than the decay fungi (Basidiomycota. Similarly, the band ratio index calculated for the protein end methyl group was found to be higher for the mould fungi than the decay fungi. Mould fungi along with the decay fungi demonstrated a positive correlation (R2=0.75 between amide I and amide II indices. The three-component multivariate, principal component analysis showed a strong correlation of amide and protein band indices.

  17. Chlorine-rich plasma polymer coating for the prevention of attachment of pathogenic fungal cells onto materials surfaces

    Science.gov (United States)

    Lamont-Friedrich, Stephanie J.; Michl, Thomas D.; Giles, Carla; Griesser, Hans J.; Coad, Bryan R.

    2016-07-01

    The attachment of pathogenic fungal cells onto materials surfaces, which is often followed by biofilm formation, causes adverse consequences in a wide range of areas. Here we have investigated the ability of thin film coatings from chlorinated molecules to deter fungal colonization of solid materials by contact killing of fungal cells reaching the surface of the coating. Coatings were deposited onto various substrate materials via plasma polymerization, which is a substrate-independent process widely used for industrial coating applications, using 1,1,2-trichloroethane as the process vapour. XPS surface analysis showed that the coatings were characterized by a highly chlorinated hydrocarbon polymer nature, with only a very small amount of oxygen incorporated. The activity of these coatings against human fungal pathogens was quantified using a recently developed, modified yeast assay and excellent antifungal activity was observed against Candida albicans and Candida glabrata. Plasma polymer surface coatings derived from chlorinated hydrocarbon molecules may therefore offer a promising solution to preventing yeast and mould biofilm formation on materials surfaces, for applications such as air conditioners, biomedical devices, food processing equipment, and others.

  18. Nano-electrocatalyst materials for low temperature fuel cells:A review

    Institute of Scientific and Technical Information of China (English)

    K. Vignarooban; J. Lin; A. Arvay; S. Kolli; I. Kruusenberg; K. Tammeveski; L. Munukutla; A. M. Kannan

    2015-01-01

    Low temperature fuel cells are an attractive technology for transportation and residential applica‐tions due to their quick start up and shut down capabilities. This review analyzed the current status of nanocatalysts for proton exchange membrane fuel cells and alkaline membrane fuel cells. The preparation process influences the performance of the nanocatalyst. Several synthesis methods are covered for noble and non‐noble metal catalysts on various catalyst supports including carbon nanotubes, carbon nanofibers, nanowires, and graphenes. Ex situ and in situ characterization methods like scanning electron microscopy, transmission electron microscopy, X‐ray photoelectron spectroscopy and fuel cell testing of the nanocatalysts on various supports for both proton exchange and alkaline membrane fuel cells are discussed. The accelerated durability estimate of the nanocat‐alysts, predicted by measuring changes in the electrochemically active surface area using a voltage cycling method, is considered one of the most reliable and valuable method for establishing durabil‐ity.

  19. Induction of Neural Progenitor-Like Cells from Human Fibroblasts via a Genetic Material-Free Approach.

    Directory of Open Access Journals (Sweden)

    Fahimeh Mirakhori

    Full Text Available A number of studies generated induced neural progenitor cells (iNPCs from human fibroblasts by viral delivering defined transcription factors. However, the potential risks associated with gene delivery systems have limited their clinical use. We propose it would be safer to induce neural progenitor-like cells from human adult fibroblasts via a direct non-genetic alternative approach.Here, we have reported that seven rounds of TAT-SOX2 protein transduction in a defined chemical cocktail under a 3D sphere culture gradually morphed fibroblasts into neuroepithelial-like colonies. We were able to expand these cells for up to 20 passages. These cells could give rise to cells that expressed neurons and glia cell markers both in vitro and in vivo.These results show that our approach is beneficial for the genetic material-free generation of iNPCs from human fibroblasts where small chemical molecules can provide a valuable, viable strategy to boost and improve induction in a 3D sphere culture.

  20. Importance of Fuel Cell Tests for Stability Assessment—Suitability of Titanium Diboride as an Alternative Support Material

    Directory of Open Access Journals (Sweden)

    Christina Roth

    2014-06-01

    Full Text Available Carbon corrosion is a severe issue limiting the long-term stability of carbon-supported catalysts, in particular in the highly dynamic conditions of automotive applications. (Doped oxides have been discussed as suitable alternatives to replace carbon, but often suffer from poor electron conductivity. That is why non-oxide ceramics, such as tungsten carbide and titanium nitride, have been discussed recently. Titanium diboride has also been proposed, due to its promising activity and stability in an aqueous electrochemical cell. In this work, Pt nanoparticles were deposited onto μm-sized TiB2 particles with improved grain size, manufactured into porous gas diffusion electrodes and tested in a realistic polymer electrolyte membrane (PEM fuel cell environment. In contrast to the model studies in an aqueous electrochemical cell, in the presence of oxygen and high potentials at the cathode side of a real fuel cell, TiB2 becomes rapidly oxidized as indicated by intensely colored regions in the membrane-electrode assembly (MEA. Moreover, already the electrode manufacturing process led to the formation of titanium oxides, as shown by X-ray diffraction measurements. This demonstrates that Cyclic Voltammetry (CV measurements in an aqueous electrochemical cell are not sufficient to prove stability of novel materials for fuel cell applications.

  1. Anode-supported ScSZ-electrolyte SOFC with whole cell materials from combined EDTA-citrate complexing synthesis process

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Hongxia; Ran, Ran; Zhou, Wei; Shao, Zongping [State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology, No. 5 Xing Mofan Road, Nanjing, JiangSu 210009 (China)

    2007-10-25

    The potential application of combined EDTA-citrate complexing process (ECCP) in intermediate-temperature solid-oxide fuel cells (IT-SOFCs) processing was investigated. ECCP-derived scandia-stabilized-zirconia (ScSZ) powder displayed low packing density, high surface area and nano-crystalline, which was ideal material for thin-film electrolyte fabrication based on dual dry pressing. A co-synthesis of NiO + ScSZ anode based on ECCP was developed, which showed reduced NiO(Ni) and ScSZ grain sizes and improved homogeneity of the particle size distribution, as compared with the mechanically mixed NiO + ScSZ anode. Anode-supported ScSZ electrolyte fuel cell with the whole cell materials synthesized from ECCP was successfully prepared. The porous anode and cathode exhibited excellent adhesion to the electrolyte layer. Fuel cell with 30 {mu}m thick ScSZ electrolyte and La{sub 0.8}Sr{sub 0.2}MnO{sub 3} cathode showed a promising maximum peak power density of 350 mW cm{sup -2} at 800 C. (author)

  2. Oxides with polyatomic anions considered as new electrolyte materials for solid oxide fuel cells (SOFCs)

    Energy Technology Data Exchange (ETDEWEB)

    Bin Hassan, Oskar Hasdinor

    2010-10-21

    Materials with Polyatomic anions of [Al{sub 2}O{sub 7}]{sup -8}, [Ti{sub 2}O{sub 8}]{sup -8} and [P{sub 2}O{sub 7}]{sup -4} were investigated with respect to their ionic conductivity properties as well as its thermal expansion properties with the aim to use them as SOFCs electrolytes. The polyatomic anion groups selected from the oxy-cuspidine family of Gd{sub 4}Al{sub 2}O{sub 9} and Gd{sub 4}Ti{sub 2}O{sub 10} as well as from pyrophosphate SnP{sub 2}O{sub 7}. The pure oxy-cuspidine Gd{sub 4}Al{sub 2}O{sub 9}, the series of Gd{sub 4}Al{sub 2-x}Mg{sub x}O{sub 9-x/2} with x=0.10-1.0 and Gd{sub 4-x}M{sub x}Al{sub 2}O{sub 9-x/2} (M=Ca, Sr) with x = 0.05-0.5 were prepared successfully by the citrate complexation method. All samples showed the crystal structure of monoclinic oxycuspidine structure with space group of P2{sub 1/c} and Z=4. No solid solution was observed for Gd{sub 4}Al{sub 2-x}Mg{sub x}O{sub 9-x/2} where additional phases of Gd{sub 2}O{sub 3} and MgO were presence. XRD semiquantitative analysis together with SEM-EDX analysis revealed that Mg{sup 2+} was not able to substitute the Al{sup 3+} ions even at low Mg{sup 2+} concentration. The solid solution limit of Gd{sub 4-x}Ca{sub x}Al{sub 2}O{sub 9-x/2} and Gd{sub 4-x}Sr{sub x}Al{sub 2}O{sub 9-x/2} was determined between 0.05-0.10 and 0.01-0.05 mol for Ca and Sr, respectively. Beyond the substitution limit Gd{sub 4}Al{sub 2}O{sub 9}, GdAlO{sub 3} and SrGd{sub 2}Al{sub 2}O{sub 7} appeared as additional phases. The highest electrical conductivity obtained at 900 C yielded {sigma}= 1.49 x 10{sup -4}Scm{sup -1} for Gd{sub 3.95}Ca{sub 0.05}Al{sub 2}O{sub 8.98}. In comparison, the conductivity of pure Gd{sub 4}Al{sub 2}O{sub 9} was {sigma}= 1.73 x 10{sup -5} Scm{sup -1}. The conductivities determined were in a similar range as those of other cuspidine materials investigated previously. The thermal expansion coefficient of Gd{sub 4}Al{sub 2}O{sub 9} at 1000 C was 7.4 x 10{sup -6}K{sup -1}. The earlier reported

  3. 燃料电池及其相关材料新进展(三)%Novel Advances in Fuel Cells and Their Relevant Materials

    Institute of Scientific and Technical Information of China (English)

    杨遇春

    1999-01-01

    Fuel cells as a high efficient, non-polluting electricity generation system are already at a near-commercial or sub-commercial stage. To meet the need for the revolution of electricity industry based fuel cells within the next few years, principal types of fuel cell systems (phosphoric acid fuel cell - PAFC, proton exchange membrane fuel cell - PEMFC, Molten carbonate fuel cell - MCFC, Solid oxide fuel cell - SOFC), their development status and economic significance were introduced. Materials and their performance requirements in fuel cell development and current status and problems in material technologies were described also. It is suggested that the domestic development goal concerning fuel cells is direct at the development of SOFC and PEMFC incorporating the superionrity of our mineral resources.

  4. Routes to copper zinc tin sulfide Cu2ZnSnS4 a potential material for solar cells.

    Science.gov (United States)

    Ramasamy, Karthik; Malik, Mohammad A; O'Brien, Paul

    2012-06-11

    Power generation through photovoltaics (PV) has been growing at an average rate of 40% per year over the last decade; but has largely been fuelled by conventional Si-based technologies. Such cells involve expensive processing and many alternatives use either toxic, less-abundant and or expensive elements. Kesterite Cu(2)ZnSnS(4) (CZTS) has been identified as a solar energy material composed of both less toxic and more available elements. Power conversion efficiencies of 8.4% (vacuum processing) and 10.1% (non-vacuum processing) from cells constructed using CZTS have been achieved to date. In this article, we review various deposition methods for CZTS thin films and the synthesis of CZTS nanoparticles. Studies of direct relevance to solar cell applications are emphasised and characteristic properties are collated. PMID:22531115

  5. Incorporation of Novel Nanostructured Materials into Solar Cells and Nanoelectronic Devices

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, Rene; Pak, Joshua; Holland, Andrew; Hunt, Alan; Bitterwolf, Thomas; Qiang, You; Bergman, Leah; Berven, Christine; Punnoose, Alex; Tenne, Dmitri

    2011-11-11

    Each of the investigators on this project has had significant accomplishments toward the production of semiconductor nanoparticles, particles, and thin films and attempts to incorporate these materials into photovoltaics or sensors; to use them for improving fluorescence diagnostics; or to employ them as cancer fighting agents. The synthesis and characterization of the nanomaterials, and more recently the device construction and testing of these materials, have been the subject of several publications and presentations by team members. During the course of the investigations, several students were fully involved as part of their graduate and undergraduate training. The nature of these projects in material development dictates that the students have gained significant experience in a diverse array of material-related topics.

  6. Rietveld texture analysis from synchrotron diffraction images. II. Complex multiphase materials and diamond anvil cell experiments

    OpenAIRE

    Wenk, HR; Lutterotti, L; P. Kaercher; Kanitpanyacharoen, W; L. Miyagi; Vasin, R

    2014-01-01

    © International Centre for Diffraction Data 2014. Synchrotron X-ray diffraction images are increasingly used to characterize crystallographic preferred orientation distributions (texture) of fine-grained polyphase materials. Diffraction images can be analyzed quantitatively with the Rietveld method as implemented in the software package Materials Analysis Using Diffraction. Here we describe the analysis procedure for diffraction images collected with high energy X-rays for a complex, multipha...

  7. Optimum dose of 2-hydroxyethyl methacrylate based bonding material on pulp cells toxicity

    OpenAIRE

    Widya Saraswati

    2010-01-01

    Background: 2-hydroxyethyl methacrylate (HEMA), one type of resins commonly used as bonding base material, is commonly used due to its advantageous chemical characteristics. Several preliminary studies indicated that resin is a material capable to induce damage in dentin-pulp complex. It is necessary to perform further investigation related with its biological safety for hard and soft tissues in oral cavity. Purpose: The author performed an in vitro test to find optimum dose of HEMA resin mon...

  8. Effects of Litter Materials on Body Weight, Packed Cell Volume and Ectoparasite Dermanyssus gallinae

    OpenAIRE

    SJ Setyawati; S Suhermiyati

    2008-01-01

    This research aimed to investigate the most suitable litter materials for broiler farming. Ninety six broiler chicken of Cobb Strain (Anwar Sierad) were used. The Experimental design used was a Completely Randomized Design (CRD) with 4 treatments and 6 replications. Each treatment unit consisted of 4 chicken. The treatment applied was litter materials, which consisted of rice husk, rice straw, wood shavings and sawdust. Data obtained were analyzed using analysis of variance and continued with...

  9. Influence of Class I interferons on performance of vascular cells on stent material in vitro

    International Nuclear Information System (INIS)

    Purpose: Numerous reports suggest that Class 1 interferons (IFNs), particularly IFN-γ, inhibit migration and proliferation of different types of human cells. The objective of the present study was to determine the effect of Class I IFNs on viability and growth characteristics of human aortic endothelial cells (ECs), smooth muscle cells (SMC) and fibroblasts (FBs) in vitro. Methods: Stainless-steel (316-l) disks were coated with fibrin meshwork containing IFN-γ or IFN-α. The discs and IFN embedded meshwork were incubated with human EC, SMC and FB, and then cultured, whereas control cells were seeded onto uncoated surfaces or plain fibrin meshwork. Concentrations of recombinant IFN varied from 5 to 20 ng/cm2. Assessment of effect on cell viability, growth and attachment was performed utilizing Alamar Blue (AB) assay. Cell morphology was assessed by scanning electron microscopy (SEM). Results: We have now shown inhibitory capacity of IFN-γ on all three types of unstimulated cells. The growth-inhibitory effect was maximal with SMC, while it was minimal with FB and EC. IFN-γ abrogated mitogenic responses of SMC but not EC and partially FB to VEGF and FGF stimulation. IFN-α was able to inhibit EC growth and, to a lesser extent, FB, and did influence growth rates of SMC. Biochemical analysis of lactate dehydrogenase activity suggested that IFN was not toxic to vascular cells. We also measured the expression of cell adhesive molecules: P- and E-selections, PECAM and ICAM-1. These molecules were upregulated by IFN in EC. Media derived from quiescent human SMC displayed low immunoreactive elastase activity, while conditional media after IFN-γ treatment but not IFN-α treatment had approximately a threefold greater activity. Conclusion: These data suggest that IFN-γ significantly inhibits SMC growth in the absence of significant endothelial toxicity and is dose-dependent; however, animal experiments are needed to further explore the antirestenotic effects of IFNs

  10. A novel approach to engineer the microstructure of solid oxide fuel cell materials

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz-Morales, J.C.; Nunez, P.; Dominguez-Gonzalez, J.M. [Departamento de Quimica Inorganica, Universidad de La Laguna, 38200-La Laguna, Tenerife (Spain); Marrero-Lopez, D. [Departamento de Fisica Aplicada I, Laboratorio de Materiales y Superficies (Unidad Asociada al C. S. I. C.) Universidad de Malaga, 29071 Malaga (Spain); Canales-Vazquez, J. [Instituto de Energias Renovables, Parque Tecnologico, Universidad de Castilla La Mancha, 02006 Albacete (Spain)

    2011-02-15

    A novel and cost-effective process to accurately control the design of 3D structures of SOFC materials is proposed. A master mould is fabricated from a rubber-based material. Metallic meshes are used to transfer any type of patterns to the rubber-based material. The reusable master mould can then be filled with a slurry of inorganic materials made of single or complex oxides and other organic components commonly used in tape-casting technology. After drying at room temperature, the master-mould can be easily peeled-off and then a slow thermal process allows obtaining a sintered material with precisely controlled features such as the size and distribution of the pore holes in the structure, the thickness of the electrode and electrolyte layers, type of patterning, etc. The potential advantages of micro- and nanoengineering of materials for energy applications are also discussed. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Alternative anode materials for methane oxidation in solid oxide fuel cells

    OpenAIRE

    Sfeir, Joseph; Grätzel, Michael

    2005-01-01

    Fuel Cells are electrochemical devices that are able to directly convert chemical energy to electrical energy, without any Carnot limitation. Hence, their energy efficiencies are relatively high. Among the various types of fuel cells, solid oxide fuel cells (SOFC) are operated at high temperatures and in principle can run on various fuels such as natural gas and hydrogen. As natural gas is sought to become one of the main fuels of the next decades, its direct feed to a SOFC is desirable as th...

  12. Materials, Proton Conductivity and Electrocatalysis in High-Temperature PEM Fuel Cells

    Science.gov (United States)

    Daletou, Maria K.; Kallitsis, Joannis; Neophytides, Stylianos G.

    Fuel cells (FCs) are interesting alternatives to existing power conversion systems since they combine high efficiency with the usage of renewable fuels. Fuel cells can generate power from a fraction of a watt to hundreds of kilowatts and can be used in automotive, stationary or portable applications.1,2,3,4,5,6 A FC is an electrochemical device that converts in a continuous manner the free energy of a chemical reaction into electrical energy (via an electrical current). This galvanic cell consists of an electrolyte (liquid or solid) sandwiched between two porous electrodes. In order to reach desirable amounts of energy power, single cell assemblies can be mechanically compressed across electrically conductive separators to fabricate stacks.

  13. Novel Materials that Enhance Efficiency and Radiation Resistance of Solar Cells Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Solar cell is the key device in generating electrical power for spacecrafts. It is an on-going challenge in maximizing electrical power available to spacecraft...

  14. Novel Materials that Enhance Efficiency and Radiation Resistance of Solar Cells Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Spacecrafts rely on arrays of solar cells to generate electrical power. It is an on-going challenge to maximize electrical power available to spacecraft while...

  15. Drug testing using a soft agar stem cell assay on patient and xenograft tumor material

    International Nuclear Information System (INIS)

    Since 1981 the authors have received 50 tumor samples from 10 different sites; over half were breast or ovary. Of the 27 that were considered suitable for cloning, 11 produced colony formation and 6 of these were drug tested. One ovarian granulosa cell tumor and its xenograft (V7) were tested against several cytotoxic agents. During a period of 16 months, sensitivity to cisplatin was relatively stable but sensitivity to vinblastine was markedly changed when the original tumor cells and original cells stored in liquid nitrogen were compared with xenograft cells. Gross histology of original tumor and xenograft were similar. Chemosensitization in vivo of a breast xenograft (Hx99) to melphalan by misonidazole was investigated. Misonidazole at a total dose of 0.5 g/kg given prior to melphalan (14 mg/kg) was an effective chemosensitizer

  16. Development of Synthetic and Natural Materials for Tissue Engineering Applications Using Adipose Stem Cells

    Directory of Open Access Journals (Sweden)

    Yunfan He

    2016-01-01

    Full Text Available Adipose stem cells have prominent implications in tissue regeneration due to their abundance and relative ease of harvest from adipose tissue and their abilities to differentiate into mature cells of various tissue lineages and secrete various growth cytokines. Development of tissue engineering techniques in combination with various carrier scaffolds and adipose stem cells offers great potential in overcoming the existing limitations constraining classical approaches used in plastic and reconstructive surgery. However, as most tissue engineering techniques are new and highly experimental, there are still many practical challenges that must be overcome before laboratory research can lead to large-scale clinical applications. Tissue engineering is currently a growing field of medical research; in this review, we will discuss the progress in research on biomaterials and scaffolds for tissue engineering applications using adipose stem cells.

  17. Characterization of the CO sensitivity of electrode materials by solid electrolyte galvanic cells

    OpenAIRE

    Plashnitsa, Vladimir

    2004-01-01

    The voltage of a galvanic cell using stabilized zirconia as a solid electrolyte can exhibit deviations from the equilibrium value given by the Nernst equation, if oxygen together with traces of an oxidizable gas like CO is exposed to one of the electrodes of the cell. This is called the non-Nernstian voltage behaviour. The basic principle of operation is not yet finally cleared since the experimental results are in accordance with two theoretical approaches. Aiming at a better understanding o...

  18. Ex situ and in situ characterization of Direct Alcohol Fuel Cell anode materials

    OpenAIRE

    Santasalo-Aarnio, Annukka

    2012-01-01

    With direct alcohol fuel cells (DAFC) the chemical energy of the reactants can be directly converted to electrical energy that can be used for instance in portable applications, independent of the electrical network. Liquid fuels such as organic alcohols are interesting for customer applications because they are more facile to use and relatively safe when compared with gaseous hydrogen. However, the obstacles to commercialization are the expensive cell components, catalysts and electrolyte me...

  19. Electrode Materials, Thermal Annealing Sequences, and Lateral/Vertical Phase Separation of Polymer Solar Cells from Multiscale Molecular Simulations

    KAUST Repository

    Lee, Cheng-Kuang

    2014-12-10

    © 2014 American Chemical Society. The nanomorphologies of the bulk heterojunction (BHJ) layer of polymer solar cells are extremely sensitive to the electrode materials and thermal annealing conditions. In this work, the correlations of electrode materials, thermal annealing sequences, and resultant BHJ nanomorphological details of P3HT:PCBM BHJ polymer solar cell are studied by a series of large-scale, coarse-grained (CG) molecular simulations of system comprised of PEDOT:PSS/P3HT:PCBM/Al layers. Simulations are performed for various configurations of electrode materials as well as processing temperature. The complex CG molecular data are characterized using a novel extension of our graph-based framework to quantify morphology and establish a link between morphology and processing conditions. Our analysis indicates that vertical phase segregation of P3HT:PCBM blend strongly depends on the electrode material and thermal annealing schedule. A thin P3HT-rich film is formed on the top, regardless of bottom electrode material, when the BHJ layer is exposed to the free surface during thermal annealing. In addition, preferential segregation of P3HT chains and PCBM molecules toward PEDOT:PSS and Al electrodes, respectively, is observed. Detailed morphology analysis indicated that, surprisingly, vertical phase segregation does not affect the connectivity of donor/acceptor domains with respective electrodes. However, the formation of P3HT/PCBM depletion zones next to the P3HT/PCBM-rich zones can be a potential bottleneck for electron/hole transport due to increase in transport pathway length. Analysis in terms of fraction of intra- and interchain charge transports revealed that processing schedule affects the average vertical orientation of polymer chains, which may be crucial for enhanced charge transport, nongeminate recombination, and charge collection. The present study establishes a more detailed link between processing and morphology by combining multiscale molecular

  20. Alternative approaches of SiC and related wide bandgap materials in light emitting and solar cell applications

    International Nuclear Information System (INIS)

    Materials for optoelectronics give a fascinating variety of issues to consider. Increasingly important are white light emitting diode (LED) and solar cell materials. Profound energy savings can be done by addressing new materials. White light emitting diodes are becoming common in our lighting scene. There is a great energy saving in the transition from the light bulb to white light emitting diodes via a transition of fluorescent light tubes. However, the white LEDs still suffer from a variety of challenges in order to be in our daily use. Therefore there is a great interest in alternative lighting solutions that could be part of our daily life. All materials create challenges in fabrication. Defects reduce the efficiency of optical transitions involved in the light emitting diode materials. The donor-acceptor co-doped SiC is a potential light converter for a novel monolithic all-semiconductor white LED. In spite of considerable research, the internal quantum efficiency is far less than theoretically predicted and is likely a fascinating scientific field for studying materials growth, defects and optical transitions. Still, efficient Si-based light source represents an ongoing research field in photonics that requires high efficiency at room temperature, wavelength tuning in a wide wavelength range, and easy integration in silicon photonic devices. In some of these devices, rare earth doped materials is considered as a potential way to provide luminescence spanning in a wide wavelength range. Divalent and trivalent oxidation states of Eu provide emitting centers in the visible region. In consideration, the use of Eu in photonics requires Eu doped thin films that are compatible with CMOS technology but for example faces material science issues like a low Eu solid solubility in silica. Therefore approaches aim to obtain efficient light emission from silicon oxycarbide which has a luminescence in the visible range and can be a host material for rare earth ions. The

  1. Fundamental studies of materials, designs, and models development for polymer electrolyte membrane fuel cell flow field distributors

    Science.gov (United States)

    Nikam, Vaibhav Vilas

    Fuel cells are becoming a popular source of energy due to their promising performance and availability. However, the high cost of fuel cell stack forbids its deployment to end user. Moreover, bipolar plate is one of the critical components in current polymer electrolyte membrane fuel cell (PEMFC) system, causing severe increase in manufacturing cost. The objective of this research work is to develop new materials, design and manufacturing process for bipolar plates. The materials proposed for use were tested for corrosion resistance in simulated fuel cell conditions. After corrosion studies copper alloy (C17200) and Low Temperature Carburized (LTC) SS 316 were selected as an alternative material for bipolar plate. It was observed that though the copper alloy offered good resistance in corrosive atmosphere, the major advantage of using the alloys was good conductivity even after formation of corrosion layer compared to SS 316. However, LTC SS 316 achieved the best corrosion resistance (ever reported in current open literature at relatively low cost) with decreased contact resistance, as compared to SS 316. Due to the expensive and tedious machining for bipolar plate manufacturing, the conventional machining process was not used. Bipolar plates were manufactured from thin corrugated sheets formed of the alloy. This research also proposed a novel single channel convoluted flow field design which was developed by increasing the tortuosity of conventional serpentine design. The CFD model for novel single channel convoluted design showed uniform distribution of velocity over the entire three dimensional domain. The novel design was further studied using pressure drop and permeability models. These modeling calculations showed substantial benefit in using corrugated sheet design and novel single channel convoluted flow field design. All the concepts of materials (except for LTC SS 316), manufacturing and design are validated using various tests like long term stability

  2. Bifunctional Manganese Ferrite/Polyaniline Hybrid as Electrode Material for Enhanced Energy Recovery in Microbial Fuel Cell.

    Science.gov (United States)

    Khilari, Santimoy; Pandit, Soumya; Varanasi, Jhansi L; Das, Debabrata; Pradhan, Debabrata

    2015-09-23

    Microbial fuel cells (MFCs) are emerging as a sustainable technology for waste to energy conversion where electrode materials play a vital role on its performance. Platinum (Pt) is the most common material used as cathode catalyst in the MFCs. However, the high cost and low earth abundance associated with Pt prompt the researcher to explore inexpensive catalysts. The present study demonstrates a noble metal-free MFC using a manganese ferrite (MnFe2O4)/polyaniline (PANI)-based electrode material. The MnFe2O4 nanoparticles (NPs) and MnFe2O4 NPs/PANI hybrid composite not only exhibited superior oxygen reduction reaction (ORR) activity for the air cathode but also enhanced anode half-cell potential upon modifying carbon cloth anode in the single-chambered MFC. This is attributed to the improved extracellular electron transfer of exoelectrogens due to Fe(3+) in MnFe2O4 and its capacitive nature. The present work demonstrates for the first time the dual property of MnFe2O4 NPs/PANI, i.e., as cathode catalyst and an anode modifier, thereby promising cost-effective MFCs for practical applications. PMID:26315619

  3. Sound speed and thermal property measurements of inert materials: laser spectroscopy and the diamond-anvil cell

    Energy Technology Data Exchange (ETDEWEB)

    Zaug, J.M.

    1997-07-01

    An indispensable companion to dynamical physics experimentation, static high-pressure diamond-anvil cell research continues to evolve, with laser diagnostic, as an accurate and versatile experimental deep planetary properties have bootstrapped each other in a process that has produced even higher pressures; consistently improved calibrations of temperature and pressure under static and dynamic conditions; and unprecedented data and understanding of materials, their elasticity, equations of state (EOS), and transport properties under extreme conditions. A collection of recent pressure and/or temperature dependent acoustic and thermal measurements and deduced mechanical properties and EOS data are summarized for a wide range of materials including H2, H2O, H2S, D2S, CO2, CH4, N2O, CH3OH,, SiO2, synthetic lubricants, PMMA, single crystal silicates, and ceramic superconductors. Room P&T sound speed measurements are presented for the first time on single crystals of beta-HMX. New high-pressure and temperature diamond cell designed and pressure calibrant materials are reviewed.

  4. Development of a Hopkinson Bar Apparatus for Testing Soft Materials: Application to a Closed-Cell Aluminum Foam

    Directory of Open Access Journals (Sweden)

    Marco Peroni

    2016-01-01

    Full Text Available An increasing interest in lightweight metallic foams for automotive, aerospace, and other applications has been observed in recent years. This is mainly due to the weight reduction that can be achieved using foams and for their mechanical energy absorption and acoustic damping capabilities. An accurate knowledge of the mechanical behavior of these materials, especially under dynamic loadings, is thus necessary. Unfortunately, metal foams and in general “soft” materials exhibit a series of peculiarities that make difficult the adoption of standard testing techniques for their high strain-rate characterization. This paper presents an innovative apparatus, where high strain-rate tests of metal foams or other soft materials can be performed by exploiting the operating principle of the Hopkinson bar methods. Using the pre-stress method to generate directly a long compression pulse (compared with traditional SHPB, a displacement of about 20 mm can be applied to the specimen with a single propagating wave, suitable for evaluating the whole stress-strain curve of medium-sized cell foams (pores of about 1–2 mm. The potential of this testing rig is shown in the characterization of a closed-cell aluminum foam, where all the above features are amply demonstrated.

  5. Novel GO-LaSmO2 Nanocomposite as an Effective Electrode Material for Hydrogen Fuel Cells

    Science.gov (United States)

    El-Amin, Ayman A.; Othman, Abdelhameed M.

    2016-04-01

    Nano-composites of lanthanum-samarium oxide (LaSmO2) were prepared in the absence and presence of graphene oxide (GO) and characterized as an effective electrode material for hydrogen fuel cells. X-ray and scanning electron microscope investigations revealed grain sizes of 8 nm for LaSmO2 and 12 nm for GO-LaSmO2 composites. The x-ray diffraction pattern showed sharp peaks, indicating a well-crystallized phase indexable to a rhombohedral structure with space group R 3 C , and their structural refinement performed in the hexagonal mode. The ionic conductivity of LaSmO2 was found to be 4.12 × 10-5 S/cm, while in the presence of GO it was enhanced to 5.32 × 10-5 S/cm. The mechanism of conduction in the proposed nano-materials was investigated based on frequency exponent S. The values of S were observed to decrease with increasing temperature. This result was found to be in good agreement with the correlated barrier hopping (CBH) model. The present work revealed GO to be a conductivity enhancer that caused the GO-LaSmO2 composite to be an effective electrode material for hydrogen fuel cells.

  6. LBL coating of type I collagen and hyaluronic acid on aminolyzed PLLA to enhance the cell-material interaction

    Directory of Open Access Journals (Sweden)

    M. Y. Zhao

    2014-05-01

    Full Text Available The aim of the present work is to assemble extracellular matrix components onto poly (L-lactic acid (PLLA films using layer-by-layer (LBL depositing method to enhance the cell-material interaction. To introduce charges onto the hydrophobic and neutral PLLA surface so that the electronic assembly can be processed, poly (ethylene imine (PEI was covalently bonded to modify the PLLA films. Positively charged collagen I (Col I was then deposited onto the aminolyzed PLLA film surface in a LBL assembly manner using hyaluronic acid (HA as a negatively charged polyelectrolyte. The PEI modification efficiency was monitored via X-ray photoelectron spectroscopy (XPS measurements. The results of Surface Plasmon Resonance (SPR and Water contact angle (WCA monitoring the LBL assemble process presented that the HA/Col I deposited alternately onto the PLLA surface. The surface topography of the films was observed by Atomic force microscope (AFM. In vitro osteoblast culture found that the presence of Col I layer greatly improved the cytocompatibility of the PLLA films in terms of cell viability, cell proliferation and Alkaline Phosphatase (ALP expression. Furthermore, osteoblast extensions were found to be directed by contact guidance of the aligned Col I fibrils. Thus, these very flexible systems may allow broad applications for improve the bioactivity of polymeric materials, which might be a potential application for bone tissue engineering.

  7. Recent Progress on the Key Materials and Components for Proton Exchange Membrane Fuel Cells in Vehicle Applications

    Directory of Open Access Journals (Sweden)

    Cheng Wang

    2016-07-01

    Full Text Available Fuel cells are the most clean and efficient power source for vehicles. In particular, proton exchange membrane fuel cells (PEMFCs are the most promising candidate for automobile applications due to their rapid start-up and low-temperature operation. Through extensive global research efforts in the latest decade, the performance of PEMFCs, including energy efficiency, volumetric and mass power density, and low temperature startup ability, have achieved significant breakthroughs. In 2014, fuel cell powered vehicles were introduced into the market by several prominent vehicle companies. However, the low durability and high cost of PEMFC systems are still the main obstacles for large-scale industrialization of this technology. The key materials and components used in PEMFCs greatly affect their durability and cost. In this review, the technical progress of key materials and components for PEMFCs has been summarized and critically discussed, including topics such as the membrane, catalyst layer, gas diffusion layer, and bipolar plate. The development of high-durability processing technologies is also introduced. Finally, this review is concluded with personal perspectives on the future research directions of this area.

  8. Biomimetic poly(amidoamine hydrogels as synthetic materials for cell culture

    Directory of Open Access Journals (Sweden)

    Lenardi Cristina

    2008-11-01

    Full Text Available Abstract Background Poly(amidoamines (PAAs are synthetic polymers endowed with many biologically interesting properties, being highly biocompatible, non toxic and biodegradable. Hydrogels based on PAAs can be easily modified during the synthesis by the introduction of functional co-monomers. Aim of this work is the development and testing of novel amphoteric nanosized poly(amidoamine hydrogel film incorporating 4-aminobutylguanidine (agmatine moieties to create RGD-mimicking repeating units for promoting cell adhesion. Results A systematic comparative study of the response of an epithelial cell line was performed on hydrogels with agmatine and on non-functionalized amphoteric poly(amidoamine hydrogels and tissue culture plastic substrates. The cell adhesion on the agmatine containing substrates was comparable to that on plastic substrates and significantly enhanced with respect to the non-functionalized controls. Interestingly, spreading and proliferation on the functionalized supports are slower than on plastic exhibiting the possibility of an easier control of the cell growth kinetics. In order to favor the handling of the samples, a procedure for the production of bi-layered constructs was also developed by means the deposition via spin coating of a thin layer of hydrogel on a pre-treated cover slip. Conclusion The obtained results reveal that PAAs hydrogels can be profitably functionalized and, in general, undergo physical and chemical modifications to meet specific requirements. In particular the incorporation of agmatine warrants good potential in the field of cell culturing and the development of supported functionalized hydrogels on cover glass are very promising substrates for applications in cell screening devices.

  9. Development of a new solid-state absorber material for dye-sensitized solar cell (DSSC)

    Indian Academy of Sciences (India)

    Swapna Lilly Cyriac; B Deepika; Bhaskaran Pillai; S V Nair; K R V Subramanian

    2014-05-01

    In contrast to the conventional DSSC systems, where the dye molecules are used as light harvesting material, here a solid-state absorber was used as a sensitizer in conjunction with the dye. The materials like ZnO and Al2O3 : C, which will show optically stimulated luminescence (OSL) upon irradiation were used as extremely thin absorber layers. This novel architecture allows broader spectral absorption, an increase in photocurrent, and hence, an improved efficiency because of the mobility of the trapped electrons in the absorber material after irradiation, to the TiO2 conduction band. Nanocrystalline mesoporous TiO2 photoanodes were fabricated using these solid-state absorber materials and after irradiation, a few number of samples were co-sensitized with N719 dye. On comparing both the dye loaded photoanodes (ZnO/TiO2 and Al2O3 : C/TiO2), it can be concluded from the present studies that, the Al2O3 : C is superior to ZnO under photon irradiation. Al2O3 : C is more sensitive to photon irradiation than ZnO and hence there can be more trap centres produced in Al2O3 : C.

  10. Osteogenic differentiation of dental pulp stem cells under the influence of three different materials

    DEFF Research Database (Denmark)

    Ajlan, S. A.; Ashri, N. Y.; Aldahmash, Abdullah M.;

    2015-01-01

    materials that act as signaling molecules to enhance periodontal regeneration. Mineral trioxide aggregate (MTA) has been proven to be biocompatible and appears to have some osteoconductive properties. The objective of this study was to evaluate the effects of EMD, MTA, and PDGF on DPSC osteogenic...

  11. POWER FIELD MONITORING EQUIPMENT FROM WETLAND DETRITUS MATERIALS USING MICROBIAL FUEL CELL

    Science.gov (United States)

    The data from both laboratory and field experiments will provide useful information to assist designing an in-situ MFC system that uses detritus materials to achieve constant and useable electric energy output. The in-situ MFC systems installed in the forested wetlands at Wi...

  12. Polyaniline-coated carbon nanotubes decorated with metal nanoparticles as materials for fuel-cell electrodes

    Czech Academy of Sciences Publication Activity Database

    Stejskal, Jaroslav; Sapurina, I.

    Gargnano : Associazione Italiana di Scienza e Tecnologia delle Macromolecole, 2008. s. 121. [Advanced Polymeric Materials for Energy Resources Exploitation: Synthesis, Properties and Applications. 01.06.2008-05.06.2008, Gargnano] R&D Projects: GA ČR GA203/08/0686 Institutional research plan: CEZ:AV0Z40500505 Keywords : polyaniline * conducting polymer * noble metals Subject RIV: CD - Macromolecular Chemistry

  13. Adhesion and proliferation of neuron cells on carbon-based materials

    Czech Academy of Sciences Publication Activity Database

    Ižák, Tibor; Babchenko, Oleg; Kromka, Alexander

    Bratislava : Slovenská vákuová spoločnosť, 2014 - (Michalka, M.; Vincze, A.; Veselý, M.), s. 104-110 ISBN 978-80-971179-4-8. [School of Vacuum Technology /17./. Štrbské Pleso (SK), 02.10.2014-05.10.2014] R&D Projects: GA ČR(CZ) GBP108/12/G108 Institutional support: RVO:68378271 Keywords : diamond films * neuron cell s * adhesion * proliferation * cell cultivation Subject RIV: BO - Biophysics

  14. A new sight towards dye-sensitized solar cells material and theoretical

    CERN Document Server

    Lin, Hong

    2010-01-01

    Dye-sensitized solar cell (DSC) technology is emerging, against the current background of drastic consumption-rates of irreplaceable natural resources, as the Cinderella solution to many energy-related problems, Almost since its first appearance, it has been regarded as being the most promising alternative to conventional silicon solar cell technology due to the tremendous advantages of low cost and high theoretical energy-conversion efficiency. Review from Book News Inc.: Eight invited and peer-reviewed papers comprise this special-topic volume on a possible alternative to conventional silico

  15. Methane steam reforming kinetics over Ni-YSZ anode materials for Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Mogensen, David

    Solid Oxide Fuel Cells (SOFC) is a technology with great potential. Its high efficiency makes it a relevant alternative to existing technologies for utilizing fossil fuels and its fuel versatility makes it invaluable in the transition from a fossil fuel based energy system to on based on renewable...... energy. The overall efficiency of a fuel cell system operating on natural gas can be significantly improved by having part of the steam reforming take place inside the SOFC stack. In order to avoid large temperature gradients as a result of the highly endothermal steam reforming reaction, the amount of...

  16. Disruption and erosion on plasma facing materials with Oarai hot-cell electron beam irradiating system (OHBIS)

    International Nuclear Information System (INIS)

    To evaluate the effects of neutron irradiation on erosion behavior of plasma facing materials by plasma disruption, thermal shock tests with neutron irradiated specimens of 2-directional carbon fiber reinforced carbon composites (CFCs) were carried out at the electron beam facility ('OHBIS', Oarai Hot cell electron Beam Irradiating System) in the hot laboratory of the JMTR (Japan Materials Testing Reactor). The test conditions on CFCs were 800 MW m-2 x 25 ms and 500 MW m-2 x 40 ms. Neutron irradiation condition of CFCs in JMTR was the total fast neutron fluence of 3-6 x 1020 ncm-2 (E>1 MeV) at about 563 K. As results of these experiments, the weight loss of neutron irradiated specimens increased almost linearly with neutron fluence, and was about two times larger than that of the un-irradiated specimen. (author)

  17. Evaluation of Ca3Co2O6 as cathode material for high-performance solid-oxide fuel cell.

    Science.gov (United States)

    Wei, Tao; Huang, Yun-Hui; Zeng, Rui; Yuan, Li-Xia; Hu, Xian-Luo; Zhang, Wu-Xing; Jiang, Long; Yang, Jun-You; Zhang, Zhao-Liang

    2013-01-01

    A cobalt-based thermoelectric compound Ca(3)Co(2)O(6) (CCO) has been developed as new cathode material with superior performance for intermediate-temperature (IT) solid-oxide fuel cell (SOFC). Systematic evaluation has been carried out. Measurement of thermal expansion coefficient (TEC), thermal-stress (σ) and interfacial shearing stress (τ) with the electrolyte show that CCO matches well with several commonly-used IT electrolytes. Maximum power density as high as 1.47 W cm(-2) is attained at 800°C, and an additional thermoelectric voltage of 11.7 mV is detected. The superior electrochemical performance, thermoelectric effect, and comparable thermal and mechanical behaviors with the electrolytes make CCO to be a promising cathode material for SOFC. PMID:23350032

  18. Revealing the ultrafast charge carrier dynamics in organo metal halide perovskite solar cell materials using time resolved THz spectroscopy

    Science.gov (United States)

    Ponseca, C. S., Jr.; Sundström, V.

    2016-03-01

    Ultrafast charge carrier dynamics in organo metal halide perovskite has been probed using time resolved terahertz (THz) spectroscopy (TRTS). Current literature on its early time characteristics is unanimous: sub-ps charge carrier generation, highly mobile charges and very slow recombination rationalizing the exceptionally high power conversion efficiency for a solution processed solar cell material. Electron injection from MAPbI3 to nanoparticles (NP) of TiO2 is found to be sub-ps while Al2O3 NPs do not alter charge dynamics. Charge transfer to organic electrodes, Spiro-OMeTAD and PCBM, is sub-ps and few hundreds of ps respectively, which is influenced by the alignment of energy bands. It is surmised that minimizing defects/trap states is key in optimizing charge carrier extraction from these materials.

  19. Efficient Natural Dye-Sensitized Solar Cells Based on Spin-Coated TiO2 Anode Materials

    Science.gov (United States)

    Yu, Xiao-Hong; Sun, Zhao-Zong; Lian, Jie; Li, Yi-Tan; Chen, Yan-Xue; Gao, Shang; Wang, Xiao; Wang, Ying-Shun; Zhao, Ming-Lin

    2013-11-01

    TiO2 anode materials are prepared on ITO glass by spin-coated method. Dye-sensitized solar cells are assembled with these anodes and natural dyes extracted from radix ophiopogonis by different solvents. The formation and characterization of anode materials are confirmed by field-emission scanning electron microscopy, x-ray diffraction, UV-visible absorption spectroscopy. Photovoltaic testing results show that energy conversion efficiency could reach 1.67% with fill factor of 0.51, open-circuit voltage of 457 mV, and short-circuit photocurrent density of 7.2 mA/cm2. The short-circuit photocurrent density can reach 7.6 mA/cm2 with efficiency of 1.33.

  20. Novel Cathode and Photocathode Materials for Dye-Sensitized Solar Cells

    Czech Academy of Sciences Publication Activity Database

    Kavan, Ladislav; Vlčková Živcová, Zuzana; Krýsová, Hana; Cígler, Petr; Liska, P.; Zakeeruddin, S. M.; Grätzel, M.

    Taipei: International Society of Electrochemistry , 2015. 826. [Annual Meeting of the International Society of Electrochemistry . Green Electrochemistry for Tomorrow´s Society /66./. 04.10.2015-09.10.2015, Taipei] R&D Projects: GA ČR GA13-07724S Institutional support: RVO:61388955 Keywords : dye-sensitized solar cells * photocathodes * electrochemistry Subject RIV: CG - Electrochemistry