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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

    2014-01-01

    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 Simplisia Dan Ekstrak Daun Strobilanthus Crispus

    OpenAIRE

    Isnawati, Ani; Alegantina, Sukmayati; Raini, Mariana; B., Nikmah

    2004-01-01

    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 suat...

  5. KARAKTERISASI SIMPLISIA DAN EKSTRAK DAUN STROBILANTHUS CRISPUS

    OpenAIRE

    Ani Isnawati; Sukmayati Alegantina; Mariana Raini; Nikmah B.

    2012-01-01

    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 suat...

  6. FUEL CELL ELECTRODE MATERIALS

    Science.gov (United States)

    FUEL CELL ELECTRODE MATERIALS. RAW MATERIAL SELECTION INFLUENCES POLARIZATION BUT IS NOT A SINGLE CONTROLLING FACTOR. AVAILABLE...DATA INDICATES THAT AN INTERRELATIONSHIP OF POROSITY, AVERAGE PORE VOLUME, AND PERMEABILITY CONTRIBUTES TO ELECTRODE FUEL CELL BEHAVIOR.

  7. Perancangan, Pembuatan dan Karakterisasi Tranduser Ultrasonik 3,5 MHz Untuk Pengujian Bahan Padat

    Directory of Open Access Journals (Sweden)

    Mokhamad Halim Fathoni

    2013-03-01

    Full Text Available Dalam penelitian ini telah dibuat sepasang transduser ultrasonik untuk pengujian bahan padat. Konstruksi transduser ultrasonik yang dibuat terdiri dari holder berbahan akrilik dan kuningan, backing material berbahan styrofoam, epoxy dan busa karet, elemen aktif berbahan piezoelektrik dan matching layers menggunakan akrilik. Bahan penyusun konstruksi tersebut dilakukan pengujian terlebih dahulu untuk mengetahui pengaruhnya terhadap karakteristik transduser ultrasonik. Dan untuk menunjang pengujian, maka dibuat sebuah alat sederhana dengan metode transmisi pulsa untuk melakukan pengukuran Time of Flight(TOF gelombang ultrasonik. Karakterisasi bahan transduser dilakukan dengan melakukan beberapa tahap pengujian. Tahap pertama dilakukan  pengujian respon frekuensi pada piezoelektrik untuk mendapatkan frekuensi resonansi yang sesuai. Kemudian dilakukan pengujian bahan backing material untuk mengetahui respon impulse dari sinyal ultrasonik dan menguji bahan matching layers untuk mendapatkan faktor delay pada pengukuran. Setelah karakterisasi bahan didapatkan, maka dilanjutkan dengan implementasi transduser ultrasonik untuk pengujian cacat pada bahan. Pengujian ini menggunakan aluminium berdimensi (15x5x1cm dengan bentuk cacat yang telah ditentukan. Proses pengujian cacat ini dilakukan dengan cara scanning secara manual dengan perubahan jarak setiap 0.5 cm. Dari hasil pengujian yang telah dilakukan diperoleh  karakteristik transduser ultrasonik dengan holder berbahan akrilik, backing material berbahan styrofoam, frekuensi resonansi sebesar 3.5 MHz, bandwith sebesar 2.04 MHz, respon impulse >10 siklus, delay sebesar 1,6 us ,Q (faktor kualitas mekanis getaran harmonis sebesar 1,667 dan impedansi sebesar 78,6 ohm. Untuk pengujian cacat bahan didapatkan hasil bahwa transduser ultrasonik bisa mendeteksi adanya cacat dan mengestimasi panjang ukuran cacat dengan error pengukuran sebesar 0.5 cm. Namun, kedalaman cacat tidak bisa ditentukan sehingga

  8. 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.

  9. Materials as stem cell regulators

    Science.gov (United States)

    Murphy, William L.; McDevitt, Todd C.; Engler, Adam J.

    2014-01-01

    The stem cell/material interface is a complex, dynamic microenvironment in which the cell and the material cooperatively dictate one another's fate: the cell by remodelling its surroundings, and the material through its inherent properties (such as adhesivity, stiffness, nanostructure or degradability). Stem cells in contact with materials are able to sense their properties, integrate cues via signal propagation and ultimately translate parallel signalling information into cell fate decisions. However, discovering the mechanisms by which stem cells respond to inherent material characteristics is challenging because of the highly complex, multicomponent signalling milieu present in the stem cell environment. In this Review, we discuss recent evidence that shows that inherent material properties may be engineered to dictate stem cell fate decisions, and overview a subset of the operative signal transduction mechanisms that have begun to emerge. Further developments in stem cell engineering and mechanotransduction are poised to have substantial implications for stem cell biology and regenerative medicine. PMID:24845994

  10. Karakterisasi Permen Jeli yang Dibuat dari Hasil Formulasi Jelly Powder

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    Ellya Sinurat

    2010-06-01

    Full Text Available Penelitian karakterisasi permen jeli dengan bahan baku formula jelly powder telah dilakukan. Formula jelly powder terdiri dari campuran karaginan murni, konjak, dekstrosa, dan KCl. Jelly powder ini digunakan untuk pembuatan permen jeli dengan variasi 3,5; 4,0; 4,5; dan 5,0%. Sebagai pembanding digunakan produk permen jeli impor berbahan dasar karaginan yang sudah ada di pasaran. Untuk mengetahui kualitas permen jeli, parameter yang diamati meliputi aktivitas air, sifat fisik (kekerasan, kelengketan, dan elastisitas serta nilai organoleptik (kenampakan, bau, rasa, tekstur, elastisitas, transparansi, dan penerimaan. Hasil penelitian menunjukkan bahwa semakin tinggi konsentrasi  jelly powder menyebabkan meningkatnya kekerasan, kelengketan, dan elastisitas permen jeli. Nilai organoleptik untuk rasa, tekstur, elastisitas, transparansi, dan penerimaan yang paling baik menurut panelis adalah pada konsentrasi jelly powder 4,5%

  11. KARAKTERISASI TEPUNG BUAH LINDUR (Brugeira gymnorrhiza SEBAGAI BERAS ANALOG DENGAN PENAMBAHAN SAGU DAN KITOSAN

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    taufik - hidayat

    2014-06-01

    Full Text Available Penelitian ini bertujuan untuk mengkarakterisasi tepung lindur,menentukan formulasi beras analog, dan karakterisasi produk beras analog terpilih. Penelitian dilakukanmelalui 3 tahap yaitu pembuatan dan karakterisasi tepung buah lindur, formulasi beras analog dan pembuatananalog, serta karakterisasi produk. Hasil penelitian menunjukkan bahwa tepung lindur memiliki karbohidrat(86,10%, tanin (0,21%, amilosa (29,96%, total gula (14,75%, dan HCN (1,98 ppm. Formulasi terbaikadalah kombinasi dari tepung lindur 70% dan tepung sagu 30% dengan penambahan kitosan 0,5%. Berasanalog terpilih memiliki karbohidrat (81,58%, densitas kamba (0,80 g/mL, bobot seribu butir (18,08 g,amilosa 20,36%, serat pangan 8,16%, energi bruto (3.240 kal/g dan daya cerna pati (55,22%.Kata kunci: beras analog, buah lindur, formulasi, kitosan, sagu

  12. ISOLASI DAN KARAKTERISASI BAKTERI NITRIFIKASI DAN DENITRIFIKASI SEBAGAI KANDIDAT PROBIOTIK

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    Yosmaniar Yosmaniar

    2018-01-01

    Full Text Available Senyawa nitrogen yang tinggi pada limbah budidaya perikanan intensif dapat memperburuk kualitas air, sehingga perlu diatasi dengan penambahan probiotik untuk proses bioremediasi. Tujuan penelitian ini adalah untuk mendapatkan bakteri nitrifikasi dan denitrifikasi yang berpotensi sebagai kandidat probiotik pengendali senyawa nitrogen pada budidaya ikan air tawar. Tahap penelitian terdiri atas: 1 koleksi sampel air dan sedimen dari kolam budidaya ikan patin di kawasan minapolitan Desa Pudak Kecamatan Kumpeh Kabupaten Muaro Jambi Provinsi Jambi dan Desa Koto Mesjid Kecamatan XIII Koto Kampar Kabupaten Kampar Provinsi Riau; 2 pengujian sampel secara in vitro yang meliputi: a Isolasi dan seleksi bakteri nitrifikasi dan denitrifikasi; b Karakterisasi morfologis bakteri terpilih; c Karakterisasi fisiologi/biokimia isolat bakteri terpilih; d Karakterisasi genetika isolat bakteri terpilih dengan sekuensing 16S-rRNA. Analisis data dilakukan secara deskriptif. Berdasarkan hasil penelitian diperoleh empat isolat bakteri nitrifikasi dan empat isolate bakteri denitrifikasi. Isolat bakteri nitrifikasi Pandoraea pnomenusa strain 1318 (NP1; Pseudomonas aeruginosa strain PSE12 (NP2; Pseudomonas aeruginosa strain PSE12 (NP3; Burkholderia vietnamiensis strain NE 7 (NP4; dan denitrifikasi Achromobacter xylosoxidans strain TPL14 (DP1; Stenotrophomonas acidaminiphila strain BTY (DP2; Stenotrophomonas maltophilia strain BHWSL2 (DP3; Ochrobactrum intermedium strain: SQ 20 (DP4 Achromobacter xylosoxidans strain TPL14 (DP1; Stenotrophomonas acidaminiphila strain BTY (DP2; Stenotrophomonas maltophilia strain BHWSL2 (DP3; Ochrobactrum intermedium strain: SQ 20 (DP4; yang berpotensi digunakan sebagai kandidat probiotik pengendali senyawa nitrogen pada budidaya ikan air tawar. Wastes from an intensive aquaculture contain nitrogen compounds which, if untreated, could rapidly reduce water quality condition within the system. The addition of probiotics as bioremediation to

  13. Karakterisasi Serbuk Hasil Produksi Menggunakan Metode Atomisasi

    Directory of Open Access Journals (Sweden)

    M. Halim Asiri

    2015-07-01

    Full Text Available Abstrak : Metalurgi serbuk (powder metallurgy,yaitu merupakan teknologi produksi logam dengan bahan dasar Aluminum dengan unsur lain Ti,Mn,Mg,Si,sebagai unsur penguat sebelum diproses pencairan terlebidahulu melakukan pengujian sifat mekanik antara lain uji struktur makro dan mikro kemudianuji kekerasan (hardness tes, uji kekuatan (tensile strength. Setelah selesai diadakan pengujian sifat-sifat mekanik terhadap logam dasar, maka proses selanjutnya mencairkan logam dasar denganmelalui dapur peleburan (fornaices dengan temperature panas sekitar 1200 s/d 1350? dan titik cair logam aluminum 650?. Setelah mencair kemudian di holding time selama 20 menit selanjutnya pembuatan proses granulasi (pembutiran dengan menggunakan sistim Atomisasi Air (water atomization dengan menggunakan variasi tekanan penyemprotan sebesar 20 s/d 25 Psi, dengan debit 4 l/s,variasi waktu yg digunakan 6 s/d 8 detik. Hasil dari proses sistim metode Atomisasi ini kita dapatkan macam-macam karakteristik bentuk butiran mulai dari Mesh 8 (2360????m,mesh 16 (1180????m, mesh 30(600????m, mesh 50(300????????,mesh 100 (150????m,mesh 200 (75????m. Untuk mengetahui data-data ini melalui pengamatan dengan menggunakan mikroskop makro dan mikro.Selanjutnya bisa juga melakukan pengujian dengan menggunakan alat uji SEM dan X – Ray (XRD.Kata kunci: uji sifat – sifat mekanik, sifat bahan, komposisi kimia dan porositas (civitis Abstract : Powder metallurgy (powder metallurgy, which is a production technology with basic materialsAluminum metal with other elements Ti, Mn, Mg, Si, as a reinforcement agent before beingprocessed casting prior testing of mechanical properties among others, macro and micro structuraltest then hardness test, test of strength. After completion of the testing of mechanical properties ofthe base metal, then the next process with the base metal melt through the furnace with atemperature of about 1200 s / d in 1350 and the melting point of aluminum is 650C. After melt

  14. Pembuatan Dan Karakterisasi Kertas Pembungkus Yang Dibuat Dari Kantong Semen Bekas Dengan Pulp Jerami

    OpenAIRE

    Dormian Saragi

    2008-01-01

    Penelitian tentang pembuatan dan karakterisasi kertas yang dibuat dari campuran pulp jerami dan pulp kantong semen bekas telah dilakukan. Penelitian yang dilaksanakan dengan metode proses soda, bertujuan untuk memperoleh alternatif bahan baku kertas campuran, dari pulp jerami dan kantong semen bekas. untuk campuran 0 % pulp jerami dan 100 % pulp kantong semen bekas, diperoleh contoh kertas yang mempunyai gramatur rata-rata 108,13 gr/m2, kerapatan massa rata-rata 720,89 kg/m3, kuat tarik rata-...

  15. KARAKTERISASI CANGKANG KERANG MENGGUNAKAN XRD DAN X RAY PHYSICS BASIC UNIT

    Directory of Open Access Journals (Sweden)

    Menik Sri Wahyuni, Erna Hastuti

    2012-03-01

    Full Text Available Cangkang kerang jenis Anadara Granosa merupakan bahan keramik yang  termasuk ke dalam jenis zat padat kristal. Sebagai langkah awal dilakukan penelitian dengan sampel cangkang kerang (CaCO3  yaitu melakukan karakterisasi menggunakan dua  alat yang berbeda yaitu X Ray Diffraction (XRD dan X Ray Physics Basic Unit, ini dilakukan untuk mengetahui perbedaan antara kedua alat tersebut. Dalam karakterisasi cangkang kerang (CaCO3 menggunakan X–Ray Diffraction dan X – Ray Physics Basic  Unit  tahapan – tahapannya antara lain: (1 cangkang kerang dicuci dengan alkohol  dan  gelombang ultrasonik, (2  penghalusan secara  manual  dan  ball  milling,  (3 Karakterisasi menggunakan XRD dan X-Ray Physics Basic Unit, (4 Pengamatan serbuk cangkang kerang  menggunakan Transmission Electron Microscopy (TEM dan mikroskop inverted, (5 analisa.Dari hasil karakterisasi menggunakan XRD diketahui strukturnya adalah ortorombik, dengan nilai parameter kisi a 4.96630,  b 7.95950, c 5.75030, sedangkan untuk nilai Rp, Rwp, Rexp, RB   dan GOF masih  belum  didapatkan  hasil  yang  baik,  hal  ini disebabkan  cangkang kerang  merupakan bahan alam yangbersifat heterogen. ini dapat dilihat dari hasil foto TEM yang masih kurang jelas. Sedangkan hasil difraksi sinar x menggunakan X-Ray Physics Basic Unit tidak didapatkan puncak yang jelas, namun dapat dihitung energi tertinggi pada sudut 18o    yaitu 2,006.10-6    d -1  dan  energi terendah pada sudut 58o   sebesar 1,171.10-6   d -1. Dan dari pengamatan dengan mikroskop inverted didapatkan ukuran butir sampel antara 1.28 sampai 0.85  µF .

  16. Polymeric Materials for Cell Microencapsulation.

    Science.gov (United States)

    Aijaz, A; Perera, D; Olabisi, Ronke M

    2017-01-01

    Mammalian cells have been microencapsulated within both natural and synthetic polymers for over half a century. Specifically, in the last 36 years microencapsulated cells have been used therapeutically to deliver a wide range of drugs, cytokines, growth factors, and hormones while enjoying the immunoisolation provided by the encapsulating material. In addition to preventing immune attack, microencapsulation prevents migration of entrapped cells. Cells can be microencapsulated in a variety of geometries, the most common being solid microspheres and hollow microcapsules. The micrometer scale permits delivery by injection and is within diffusion limits that allow the cells to provide the necessary factors that are missing at a target site, while also permitting the exchange of nutrients and waste products. The majority of cell microencapsulation is performed with alginate/poly-L-lysine microspheres. Since alginate itself can be immunogenic, for cell-based therapy applications various groups are investigating synthetic polymers to microencapsulate cells. We describe a protocol for the formation of microspheres and microcapsules using the synthetic polymer poly(ethylene glycol) diacrylate (PEGDA).

  17. 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

  18. 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

  19. Sintesis dan Karakterisasi Polianilina Doping Asam Klorida dengan Metode Interfasial

    Directory of Open Access Journals (Sweden)

    Iman Rahayu

    2016-08-01

    Full Text Available The growing interest in nanostructured conducting polymers is caused by expanding area of their practical application. Conducting polymers can be used in new electronic devices (transistors, displays, sensors, energy storage and memory cells, materials for shielding electromagnetic irradiation, inhibition of corrosion, membrane constructing, catalysis and medicine. The studies of polyaniline (PANI and other conducting polymers have shown that they possess semiconducting properties. Due to its high stability and unique complex of properties, PANI was the first among conducting polymers to be used in practice as an electrode material for batteries, as a corrosion inhibitor and detecting material for sensors. PANI without dopant material possesses controlled conductivity 10-10 S∙cm-1. PANI was synthesized by the interfacial method by oxidation of aniline with ammonium peroxydisulfate (APS as an oxidant in an immiscible organic/aqueous biphasic system, with hydrochloric acid as dopant. An organic phase contained aniline dissolved in toluene, while the oxidant was dissolved in acid. The produced PANIs have conductivities in the range 0.03-0.07 S.cm−1. Their nanofiber morphology was confirmed by scanning electron microscopy (SEM. Molecular structure of synthesized PANIs was investigated by FTIR Spectroscopy. DOI :http://dx.doi.org/10.15408/jkv.v0i0.3143

  20. Isolasi dan Karakterisasi Bakteriosin yang Dihasilkan Oleh Lactobacillus lactis dari Sedimen Laut

    Directory of Open Access Journals (Sweden)

    Rofiq Sunaryanto

    2015-04-01

    Full Text Available Telah dilakukan isolasi dan karakterisasi bakteriosin yang dihasilkan oleh Lactobacillus lactis yang berasal dari sedimen laut. Karakterisasi bakteriosin meliputi uji aktivitas antimikroba, stabilitas terhadap suhu, pH, penambahan enzim, surfaktan, dan stabilitas bakteriosin terhadap penyinaran lampu UV. Aktivitas antimikroba bakteriosin diuji melawan bakteri uji Escherichia coli ATCC 25922, Enterococcus faecalis ATCC 29212, Bacillus subtilis ATCC 66923, Staphyllococcus aureus ATCC 25923, Lactobacillus plantarum, Lactobacillus bulgaricus, Lactobacillus casei, dan Candida albican. Hasil penelitian menunjukkan bahwa bakteriosin mampu menghambat pertumbuhan E.coli ATCC 25922, E. faecalis ATCC 29212, S. aureus ATCC 25923 dan B. subtilis ATCC 66923, namun demikian tidak mampu menghambat pertumbuhan L. plantarum, L. bulgaricus, L. casei, dan C. albican. Bakteriosin yang dihasilkan oleh Lactobacillus lactis stabil terhadap pemanasan sampai dengan suhu 70 °C dan stabil pada rentang pH 3 sampai dengan 7. Aktivitas bakteriosin hilang dengan penambahan tripsin, pepsin, dan proteinase-K, namun aktivitas bakteriosin stabil terhadap penambahan a-amilase. Penambahan tween 20, tween 80, dan EDTA mampu meningkatkan aktivitas bakteriosin sebesar 1,1 sampai dengan 1,2 kali dibandingkan dengan tanpa penambahan surfaktan. Penyinaran lampu UV selama 15 menit tidak berpengaruh terhadap aktivitas bakteriosin.

  1. Harnessing cell-material interaction to control cell fate: design ...

    Indian Academy of Sciences (India)

    Rajat K Das

    2017-10-26

    Oct 26, 2017 ... Harnessing cell-material interaction to control cell fate: design principle of advanced functional hydrogel materials. †. RAJAT K DAS. ∗. Materials Science Centre, Indian Institute of Technology, Kharagpur, West Bengal, India. E-mail: rajat@matsc.iitkgp.ernet.in. MS received 15 August 2017; revised 29 ...

  2. 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 ...

  3. Advanced materials for solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, T.; Stevenson, J.

    1995-12-31

    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.

  4. KARAKTERISASI ANTENA MIKROSTRIP PATCH SEGITIGA SAMASISI DENGAN FREKUENSI KERJA 2,4 GHz UNTUK KOMUNIKASI WIRELESS

    Directory of Open Access Journals (Sweden)

    Rolly Ega Suganda

    2016-10-01

    Full Text Available Telah dibuat antena mikrostrip patch segitiga samasisi dengan frekuensi kerja 2,4 GHz. Antena mikrostrip patch segitiga dipilih karena memiliki dimensi yang lebih kecil untuk menghasilkan radiasi dan frekuensi kerja yang sama dibandingkan bentuk geometris lainnya. Mikrostrip patch segitiga samasisi dibuat melalui tahap-tahap simulasi, fabrikasi, dan karakterisasi. Program simulasi antena mikrostrip dibuat menggunakan fitur GUI pada pemrograman Matlab. Antena yang telah difabrikasi, dibuat pada substrat FR4 dengan  4,7 pada ketebalan 1,6 mm dan 1,0 mm, variasi yang diterapkan adalah ukuran substrat yang dibuat pada luasan 55mmx55mm dan 60mmx60 mm, dengan total keseluruhan berjumlah empat sampel antena. Pada kondisi ideal keempat sampel harus memiliki return loss -54,4223 dB; VSWR 1,00; impedansi 49,81 ohm; dan gain 6,93 pada ketebalan substrat 1,6 mm dan 4,89 pada ketebalan substrat 1,0 mm. Hasil karakterisasi yang telah dilakukan didapatkan nilai return loss keempat sampel berurutan sebesar -19,558; -20,416; -17,25 dan -8,97 dB, VSWR berurutan bernilai 1,24; 1,21; 1,32 dan 2,26, Impedansi bernilai 56,734; 56,457; 54,069 dan 55,641 ohm, dan gain bernilai 2,21; 2,23; 2,1 dan 2,22 dB. Pola radiasi azimuth dan polarisasi membentuk kuncup besar dan kuncup belakang yang dominan, padahal pada kondisi ideal kuncup belakang dominan hanya terjadi pada antena omnidirectional. Pola radiasi elevasi membentuk pola menyerupai setengah lingkaran yang tidak sempurna ke arah gain maksimum. Dari keempat sampel, hanya antena empat yang tidak memenuhi syarat untuk digunakan pada frekuensi kerja 2,4 GHz, karena memiliki return loss dan VSWR yang tidak memenuhi standar. Kata kunci: komunikasi wireless, antena mikrostrip patch segitiga, Matlab

  5. 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.

  6. New materials and technology for cell immobilization.

    Science.gov (United States)

    Salter, G J; Kell, D B

    1991-06-01

    The choice of support materials for immobilizing cells is rapidly expanding. The literature that has appeared over the past year suggests that hydrogels will remain the first choice for the forseeable future, even though they are associated with many widely recognized problems. There is increasing interest in the use of tougher polymeric materials, and especially of inorganic ceramic supports. However, the most suitable cell support can be selected only after the process or form of reactor in which it is to be used has been assessed.

  7. Harnessing cell-material interaction to control cell fate: design ...

    Indian Academy of Sciences (India)

    Rajat K Das

    2017-10-26

    Oct 26, 2017 ... advancement in engineered hydrogel materials as such scaffold to control cell fate. Keywords. Extracellular matrix; hydrogel .... vided useful model systems to identify principles that would help design synthetic ..... tool to generate nanoscale periodic patterns that influ- enced stem cell differentiation.

  8. Karakterisasi kulit kayu tingi (Ceriops tagal sebagai bahan penyamak nabati

    Directory of Open Access Journals (Sweden)

    Emiliana Kasmudjiastuti

    2014-12-01

    Full Text Available Tingi (Ceriops tagal bark was highly potential as tanning materials due to high tannin concentration. The aim of the study was to determine the characterization of properties of tanning material made from tingi bark, including the tannin levels, the non-tannin levels, the tannin type, the absorption level of the solution and the FTIR spectrum analysis. The method used in this research was countercurrent system in the extraction process, feed solution preparation process, the thickening process, powder formation process conducted with the aid of Rotavapor- 151 Standard, and testing. The results showed that the tingi bark contains tannin level 70.91% and non-tannin levels 10.63%. Tannins from tingi bark were classified as procyanidin condensed tannins type and the absorption values obtained maximum value at wavelength 490 nm. The FTIR spectral data indicated that tingi tannins contained hydroxyl group (ⱱ O-H; ⱱ N-H in the area (3467.418-3057.025 cm-1, aromatic group (ⱱ C-H in the area of 2875,733 cm-1, ⱱ C=O (ester group in tanned material in the area (1747.442-1612.422 cm-1, ⱱ-OH; R-COO-in the area of 1444.626 cm-1 and ⱱ(SO42 -; R-SO3; R-SO3H in the area (1112.823-1062.729 cm-1.

  9. Upconverter solar cells: materials and applications

    NARCIS (Netherlands)

    de Wild, J.; Meijerink, A.; Rath, J.K.; van Sark, W.G.J.H.M.; Schropp, R.E.I.

    2011-01-01

    Spectral conversion of sunlight is a promising route to reduce spectral mismatch losses that are responsible for the major part of the efficiency losses in solar cells. Both upconversion and downconversion materials are presently explored. In an upconversion process, photons with an energy lower

  10. Perovskite Materials: Solar Cell and Optoelectronic Applications

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Bin [ORNL; Geohegan, David B [ORNL; Xiao, Kai [ORNL

    2017-01-01

    Hybrid organometallic trihalide perovskites are promising candidates in the applications for next-generation, high-performance, low-cost optoelectronic devices, including photovoltaics, light emitting diodes, and photodetectors. Particularly, the solar cells based on this type of materials have reached 22% lab scale power conversion efficiency in only about seven years, comparable to the other thin film photovoltaic technologies. Hybrid perovskite materials not only exhibit superior optoelectronic properties, but also show many interesting physical properties such as ion migration and defect physics, which may allow the exploration of more device functionalities. In this article, the fundamental understanding of the interrelationships between crystal structure, electronic structure, and material properties is discussed. Various chemical synthesis and processing methods for superior device performance in solar cells and optoelectronic devices are reviewed.

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

    Directory of Open Access Journals (Sweden)

    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.

  12. 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...

  13. Hybrid Solar Cells: Materials, Interfaces, and Devices

    Science.gov (United States)

    Mariani, Giacomo; Wang, Yue; Kaner, Richard B.; Huffaker, Diana L.

    Photovoltaic technologies could play a pivotal role in tackling future fossil fuel energy shortages, while significantly reducing our carbon dioxide footprint. Crystalline silicon is pervasively used in single junction solar cells, taking up 80 % of the photovoltaic market. Semiconductor-based inorganic solar cells deliver relatively high conversion efficiencies at the price of high material and manufacturing costs. A great amount of research has been conducted to develop low-cost photovoltaic solutions by incorporating organic materials. Organic semiconductors are conjugated hydrocarbon-based materials that are advantageous because of their low material and processing costs and a nearly unlimited supply. Their mechanical flexibility and tunable electronic properties are among other attractions that their inorganic counterparts lack. Recently, collaborations in nanotechnology research have combined inorganic with organic semiconductors in a "hybrid" effort to provide high conversion efficiencies at low cost. Successful integration of these two classes of materials requires a profound understanding of the material properties and an exquisite control of the morphology, surface properties, ligands, and passivation techniques to ensure an optimal charge carrier generation across the hybrid device. In this chapter, we provide background information of this novel, emerging field, detailing the various approaches for obtaining inorganic nanostructures and organic polymers, introducing a multitude of methods for combining the two components to achieve the desired morphologies, and emphasizing the importance of surface manipulation. We highlight several studies that have fueled new directions for hybrid solar cell research, including approaches for maximizing efficiencies by controlling the morphologies of the inorganic component, and in situ molecular engineering via electrochemical polymerization of a polymer directly onto the inorganic nanowire surfaces. In the end, we

  14. Isolasi dan karakterisasi mutan sal4 di ragi (Saccharomyces cereviceae

    Directory of Open Access Journals (Sweden)

    Ni Nyoman Tri Puspaningsih

    1995-03-01

    Full Text Available Recently, genetics manipulation in yeast Saccharomyces cereviceae have much been done. It because yeast can be used as a host cell alternative in the forign protein expression, therefore information about fidelity from yeast should be studied. Preliminary study showed that sal4 gene has assumed to has a role in translation fidelity control and/or termination factor. To study the gene function, mutation in yeast BSC483/1a has been done by Ethylmethane sulphonate. Mutants wished are mutated at sal4 locus and have characteristic of both allosuppressor and omnipotent suppressor. Phenotype of alosuppresor mutants were indicated by white colour consistency in YPD and Y8 medium, temperature sensitivity, paremomcyn sensitivity and growth rate. Quantitatively, effectiveness as omnipotent suppressor has been done by using gene fuion between PGK and β-galaktosidase. The result showed that BSC483/1a strain could be mutated by Ethylmethane sulphonate 1% and produced eight allosuppressor mutants. Two of them (Number 8 and 10 have characteristic of temperature sensitivity, and the two others (Number 1 and 13 were mutated at sal4 gene locus. Characterize of sal4 mutants (1 and 13 didn't show temperature sensitive and have growth rate re;atively more slowly than the wild type. Mutant (number 13 could suppress nonsense mutation (realthrough at termination codon UAG with β-galaktosidase activity as amount 2.70 unit/ml.

  15. Properties of cathode materials in alkaline cells

    International Nuclear Information System (INIS)

    Salkind, A.J.; McBreen, J.; Freeman, R.; Parkhurst, W.A.

    1985-01-01

    Conventional and new cathode materials in primary and secondary alkaline cells were investigated for stability, structure, electrochemical reversibility and efficiency. Included were various forms of AgO for reserve-type silver-zinc batteries, a new material - AgNiO/sub 2/ - and several nickel electrodes for nickel-cadmium and nickel-hydrogen cells for aerospace applications. A comparative study was made of the stability of electroformed and chemically prepared AgO. Stability was correlated with impurities detected by XPS and SAM. After the first discharge AgNiO/sub 2/ can be recharged to the monovalent level. The discharge product is predominantly silver. Plastic-bonded nickel electrodes display a second plateau on discharge. Additions of Co(OH)/sub 2/ largely eliminate this

  16. Properties of cathode materials in alkaline cells

    Science.gov (United States)

    Salkind, A. J.; McBreen, J.; Freeman, R.; Parkhurst, W. A.

    1984-04-01

    Conventional and new cathode materials in primary and secondary alkaline cells were investigated for stability, structure, electrochemical reversibility and efficiency. Included were various forms of AgO for reserve type silver zinc batteries, a new material - AgNiO2 and several nickel electrodes for nickel cadmium and nickel hydrogen cells for aerospace applications. A comparative study was made of the stability of electroformed and chemically prepared AgO. Stability was correlated with impurities. After the first discharge AgNiO2 can be recharged to the monovalent level. The discharge product is predominantly silver. Plastic bonded nickel electrodes display a second plateau on discharge. Additions of Co(OH)2 largely eliminate this.

  17. Karakterisasi dan Aplikasi Enzim Transglutaminase dari Streptoverticillium ladakanum pada Daging Lumat IKan Mata Goyang

    Directory of Open Access Journals (Sweden)

    Yusro Nuri Fawzya

    2011-12-01

    Full Text Available Telah dilakukan karakterisasi enzim transglutaminase mikroba (MTGase yang diproduksi dari Streptoverticillium ladakanumdengan menggunakan media yang mengandung limbah cair tahu dan hidrolisat tepung tapioka. Enzim MTGase yang dikarakteris as i merupakan enzim kasar yang telah dipekatkan menggunakan ultrafiltrasi dan dikeringbekukan. Enzim ini kemudian diaplikasikan pada daging lumat ikan mata goyang (Priacanthus macracanthus lalu diamati sifat fisik (tekstur produk restrukturisasi yang dihasilkan. Sebagai pembanding,  dilakukan aplikasi TGase komersial (KTGase pada daging lumat yang sama. Penambahan TGase dilakukan dengan 2 cara, yaitu:  (1 bersama-sama dengan garam NaCl 1%, (2 bersama-sama dengan garam NaCl 1% dan sodium kaseinat 1%. Sebagai control adalah daging lumat ditambah garam N aCl 1% (tanpa penambahan enzim TGase. Hasil penelitian menunjukkan bahwa MTGase dari S. ladakanumbekerja optimum pada pH 8 dan suhu 55°C. Aktivitas enzim ini relatif tidak terpengaruh oleh adanya ion logam Ca2+,Mg2+, Na+, dan K+maupun inhibitor seperti ethylenediaminetetraacetic acid(EDTA, dan phenylmethyl-sulfonylfluoride(PMSF. Enzim MTGase tanpa penambahan sodium kaseinat menunjukkan kemampuan membentuk gel yang tidak berbeda dengan TGase komersial, menghasilkan kekuatan gel 16848 g mm dan nilai kekenyalan 0,97. Enzim ini juga terbukti dapat meningkatkan kekuatan gel, kekenyalan, dan kepadatan produk restrukturisasi daging lumat ikan yang hanya ditambah garam NaCl saja atau yang ditambah garam NaCl dan sodium kaseinat.

  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. KARAKTERISASI ENZIM KITOSANASE DAR] ISOLAT BAKTERI KPU 2123 DAN APLIKASINYA UNTUK PRODUKS1 OLIGOMER KITOSAN

    Directory of Open Access Journals (Sweden)

    Yusro Nuri Fawzya

    2009-06-01

    Full Text Available Penelitian ini merupakan sebagian dari rangkaian penelitian mengenai eksplorasi enzim kitinolitik dari mikroba lingkungan laut, khususnya dari limbah udang. Tujuan penelitian ini adalah untuk mengidentifikasi isolat bakteri KPU 2123 dari limbah udang, mengkarakterisasi dan mengaplikasikan enzim kitosanase yang dihasilkan oleh bakteri tersebut untuk produksi oligomer kitosan dan menguji bioaktivitas oligomer kitosan tersebut sebagai antitumor dan antibakteri. Karakterisasi enzim dilakukan dengan menguji aktivitas enzim pada berbagai suhu dan pH. Selain itu juga ditentukan besarnya aktivitas yang tersisa setelah enzim diinkubasi pada suhu dan lama waktu tertentu. Pengaruh ion logam terhadap aktivitas enzim juga dilihat dengan mereaksikan enzim dengan 1 mM ion logam dalam bentuk larutan khlorida. Hasil penelitian menunjukkan bahwa berdasarkan analisis gen 16S-rRNA, isolat bakteri KPU 2123 memiliki kemiripan 95% dengan Stanotrophomonas maltophilia. Enzim kitosanase dari isolat ini bekerja optimal pada suhu 50 ºC dan pH 6. Enzim ini cukup stabil pada suhu 37 ºC selama 120 menit. Penambahan ion logam berpengaruh terhadap aktivitas enzim. Ion logam Zn²+ (sebagai garam klorida 1 mM menghambat 100% aktivitas enzim tersebut. Penggunaan enzim kitosanase dalam menghidrolisis substrat kitosan, menghasilkan oligomer kitosan yang mengandung tetramer, pentamer dan heksamer Oligor kitosan tersebut mampu menghambat pertumbuhan bakteri Staphylococcus aureus sebesar 10,06% dan dapat menyebabkan kematian sel HeLa dengan LC50 pada dosis 120 ppm.

  20. Karakterisasi Carica pubescens di Dataran Tinggi Dieng, Jawa Tengah berdasarkan sifat morfologi, kapasitas antioksidan, dan pola pita protein

    Directory of Open Access Journals (Sweden)

    AINUN NIKMATI LAILY

    2012-05-01

    Full Text Available Laily AN, Suranto, Sugiyarto. 2012. Karakterisasi Carica pubescens di Dataran Tinggi Dieng, Jawa Tengah berdasarkan sifat morfologi, kapasitas antioksidan, dan pola pita protein. Bioteknologi 9: 7-13. Carica pubescens Lenne & K. Koch merupakan jenis tanaman buah yang pertamakali dibudidayakan di Amerika Selatan dan beradaptasi pada lingkungan dataran tinggi, misalnya Dataran Tinggi Dieng, Jawa Tengah (∼2000 m dpl. C. pubescens memiliki daerah persebaran sempit dan variasi intraspesies terbatas atau belum diketahui. Oleh karenanya, diperlukan informasi mengenai karakter tanaman pada berbagai ketinggian sehingga dimungkinkan untuk memperluas daerah penyebaran melalui transplantasi di daerah lain. Karakterisasi dapat dilakukan berdasarkan karakter morfologi, kandungan kimia, dan pola pita protein. Penelitian ini bertujuan untuk mendeskripsikan karakter morfologi, kandungan kimia (kapasitas antioksidan, dan pola pita protein dengan pewarnaan commasie brillian blue pada C. pubescens di Dataran Tinggi Dieng. Penelitian lapangan dilakukan di Desa Kejajar (1400 m dpl, Patak Banteng (1900 m dpl, dan Sembungan (2400 m dpl. Pengamatan karakter morfologi dilakukan di lapangan dan dilanjutkan di laboratorium. Karakter morfologi, kandungan kimia (kapasitas antioksidan, dan pola pita protein C. pubescens dianalisis secara deskriptif. Hasil penelitian menunjukkan bahwa karakter morfologi C. pubescens di Dataran Tinggi Dieng bervariasi pada batang, daun, dan buah. Kapasitas antioksidannya bervariasi dengan urutan dari ketinggian 2400 m dpl > 1900 m dpl > 1400 m dpl. Pola pita proteinnya tidak bervariasi antar ketinggian, namun berbeda dengan C. papaya. Keseragaman pola pita protein menunjukkan kestabilan genetik C. pubescens tidak dipengaruhi oleh perubahan lingkungan.

  1. KARAKTERISASI TEBAL LAPISAN BATAS FLUIDA NANO ZrO2 DI PERMUKAAN PEMANAS PADA PROSES KONVEKSI ALAMIAH

    Directory of Open Access Journals (Sweden)

    V. Indriati Sri Wardhani

    2015-10-01

    Full Text Available ABSTRAK KARAKTERISASI Tebal Lapisan Batas Fluida Nano ZrO2 di permukaan pemanas pada Proses Konveksi Alamiah. Pendinginan sistem sangat dipengaruhi oleh proses perpindahan panas konveksi dari sumber panas ke fluida pendingin. Biasanya sebagai fluida pendingin digunakan fluida konvensional seperti air. Pendinginan suatu sistem dengan air tersebut dapat ditingkatkan dengan menggunakan fluida lain seperti fluida nano, yaitu fluida yang dibuat dari campuran air ditambah partikel dengan ukuran nano. Peneliti Batan Bandung telah membuat fluida nano ZrO2 dari bahan local. Telah dibuat pula peralatan eksperimen untuk mempelajari sifat-sifat termohidrolik fluida nano tersebut. Hal ini dilakukan untuk mendapatkan fluida nano yang tepat jika digunakan sebagai fluida pendingin sistem. Dalam penelitian ini dilakukan eksperimen untuk mempelajari sifat-sifat termohidrolik fluida nano ZrO2 yang terbuat dari campuran air dengan partikel nano ZrO2 yang berukuran 10-7-10-9nm dengan konsentrasi 1 gr/lt yang digunakan sebagai pendingin pada proses pendinginan konveksi alamiah. Proses tersebut sangat bergantung pada perubahan temperatur dari sumber panas ke fluida pendingin. Dalam pendinginan konveksi alamiah perubahan temperatur itu akan terjadi di dalam tebal lapisan batas termalnya. Oleh karena itu perlu diteliti tebal lapisan batas termal dari fluida nano ZrO2 yang selanjutnya juga dapat untuk menentukan kecepatan aliran lokalnya. Eksperimen dilakukan melalui proses perpindahan panas konveksi alamiah dengan memasukkan beberapa variasi daya pemanas, kemudian dilakukan pengukuran temperatur di beberapa titik secara horizontal untuk melihat distribusi temperaturnya. Hasil pengukuran distribusi temperatur tersebut dapat digunakan untuk menentukan tebal lapisan batas dan kecepatan alirannya. Diperoleh bahwa tebal lapisan batas termal dan kecepatan konveksi alamiah fluida nano ZrO2 tidak jauh berbeda dari fluida konvensional air. Kata kunci: Lapisan batas, fluida

  2. 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.

  3. Mechanics of Granular Materials (MGM) Cell

    Science.gov (United States)

    1996-01-01

    One of three Mechanics of Granular Materials (MGM) test cells after flight on STS-79 and before impregnation with resin. Note that the sand column has bulged in the middle, and that the top of the column is several inches lower than the top of the plastic enclosure. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditons that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: University of Colorado at Boulder

  4. Mechanics of Granular Materials Test Cell

    Science.gov (United States)

    1998-01-01

    A test cell for Mechanics of Granular Materials (MGM) experiment is shown from all three sides by its video camera during STS-89. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditons that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: NASA/Marshall Space Flight Center (MSFC)

  5. Bladder reconstruction--from cells to materials.

    Science.gov (United States)

    Southgate, J; Cross, W; Eardley, I; Thomas, D F M; Trejdosiewicz, L K

    2003-01-01

    Surgical reconstruction of the urinary bladder is performed on patients of all ages for a diverse range of conditions, including congenital abnormalities, bladder dysfunction, trauma and cancer. The most common material utilized to augment or replace the bladder during these procedures is a segment of the patient's own intestine. However, this procedure ('enterocytoplasty') is associated with significant clinical complications that arise due to the exposure of the epithelial lining of the intestine to urine. A number of alternative approaches are being actively developed to find a practical and functional substitute for native bladder tissue. These range from 'composite enterocystoplasty', where the de-epithelialized intestine wall is lined with bladder epithelial cells that have been propagated in vitro, to augmenting the urinary system with natural or synthetic biomaterials that may incorporate in vitro-propagated cells. However, if tissue-engineered products are to have therapeutic application in bladder reconstruction, a number of issues remain to be addressed; these issues are discussed briefly below.

  6. 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

  7. Isolasi dan Karakterisasi Sifat Pati Kacang Hijau (Vigna radiata L. Beberapa Varietas Lokal Indonesia

    Directory of Open Access Journals (Sweden)

    Priyanto Triwitono

    2017-09-01

    Full Text Available Mung beans is a kind of legumes that possesses a potential  amylose to produce low calories RS-3. Studies on the characteristics of the starch will be useful for the treatment of obesity in the future. Isolation and characterization of the properties of mung bean starch of 4 local Indonesian varieties (Walet, Sriti, Murai, and Vima-1 have done. Isolation of starch using a modified method of Hoover. The analyzed properties of starch consist of starch content, amylose content, granular shape, color, swelling power, WHC, the blue value, amylograph and crystallinity properties. The results indicated that the mung bean varieties Walet have the highest amylose content (55.39%, that’s potential as source of  RS-3. Mung beans Walet have the 42.11% of starch content; 35.33% of yield starch; 99.63%  of starch purity; 17.11 g/g of highest swelling power; 65.26 g/g of WHC; 59.36 g/g  of OHC; 8.92% of blue value; Oval granular shape; white  color (88.09 of  Lightness; 78.7 °C of gelatinization temperature; tipe C of X-ray diffraction pattern, and 1430 Cp of the fastest retrograded starch viscosity. ABSTRAK Kacang hijau merupakan jenis kacang-kacangan sumber pati beramilosa tinggi yang potensial menghasilkan RS-3 tinggi dan rendah kalori. Kajian tentang karakteristik patinya akan membuka peluang pemanfaatannya untuk penanganan obesitas di masa datang. Telah dilakukan isolasi dan karakterisasi sifat-sifat pati kacang hijau dari 4 varietas lokal Indonesia (Walet, Sriti, Murai, dan Vima-1. Isolasi pati menggunakan metode Hoover yang dimodifikasi dan sifat-sifat pati yang dianalisis meliputi kadar pati, amilosa, bentuk granula, warna pati, swelling power, WHC, blue value, viskositas, dan sifat kristalinitas pati. Hasil isolasi dan analisis menunjukkan bahwa kacang hijau varietas Walet memiliki kadar amilosa paling tinggi (55,39%, sehingga potensial sebagai bahan dasar RS-3. Kacang hijau Walet menghasilkan kadar pati 42,11%; rendemen pati 35

  8. Modeling Emerging Solar Cell Materials and Devices

    Science.gov (United States)

    Thongprong, Non

    Organic photovoltaics (OPVs) and perovskite solar cells are emerging classes of solar cell that are promising for clean energy alternatives to fossil fuels. Understanding fundamental physics of these materials is crucial for improving their energy conversion efficiencies and promoting them to practical applications. Current density-voltage (JV) curves; which are important indicators of OPV efficiency, have direct connections to many fundamental properties of solar cells. They can be described by the Shockley diode equation, resulting in fitting parameters; series and parallel resistance (Rs and Rp), diode saturation current ( J0) and ideality factor (n). However, the Shockley equation was developed specifically for inorganic p-n junction diodes, so it lacks physical meanings when it is applied to OPVs. Hence, the puRposes of this work are to understand the fundamental physics of OPVs and to develop new diode equations in the same form as the Shockley equation that are based on OPV physics. We develop a numerical drift-diffusion simulation model to study bilayer OPVs, which will be called the drift-diffusion for bilayer interface (DD-BI) model. The model solves Poisson, drift-diffusion and current-continuity equations self-consistently for charge densities and potential profiles of a bilayer device with an organic heterojunction interface described by the GWWF model. We also derive new diode equations that have JV curves consistent with the DD-BI model and thus will be called self-consistent diode (SCD) equations. Using the DD-BI and the SCD model allows us to understand working principles of bilayer OPVs and physical definitions of the Shockley parameters. Due to low carrier mobilities in OPVs, space charge accumulation is common especially near the interface and electrodes. Hence, quasi-Fermi levels (i.e. chemical potentials), which depend on charge densities, are modified around the interface, resulting in a splitting of quasi-Fermi levels that works as a driving

  9. Advanced materials for solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, T.R.; Stevenson, J.; Paulik, S.

    1996-12-31

    Purpose of the research is to improve the properties of current state- of-the-art materials used for SOFCs. The project includes interconnect development, high-performance cathode, electrochemical testing, and accelerated testing. This document reports results of mechanical tests (bend strength, elastic modulus, fracture strength) of acceptor-substituted lanthanum chromite (interconnect material).

  10. Solid oxide fuel cell (sofc) materials

    CERN Document Server

    Saravanan, R

    2018-01-01

    Developing materials for SOFC applications is one of the key topics in energy research. The book focuses on manganite structured materials, such as doped lanthanum chromites and lanthanum manganites, which have interesting properties: thermal and chemical stability, mixed ionic and electrical conductivity, electrocatalytic activity, magnetocaloric property and colossal magnetoresistance (CMR).

  11. Solid oxide fuel cell (SOFC) materials

    CERN Document Server

    Saravanan, R

    2018-01-01

    Developing materials for SOFC applications is one of the key topics in energy research. The book focuses on manganite structured materials, such as doped lanthanum chromites and lanthanum manganites, which have interesting properties: thermal and chemical stability, mixed ionic and electrical conductivity, electrocatalytic activity, magnetocaloric property and colossal magnetoresistance (CMR).

  12. PEMBUATAN DAN KARAKTERISASI ARANG DARI BATANG TANAMAN GUMITIR (Tagetes erecta PADA BERBAGAI SUHU DAN WAKTU PIROLISIS

    Directory of Open Access Journals (Sweden)

    I Made Siaka

    2017-03-01

    Full Text Available ABSTRAK: Telah dilakukan penelitian tentang pembuatan dan karakterisasi arang dari batang tanaman gumitir (Tagetes erecta pada berbagai suhu dan waktu pirolisis. Penelitian ini dilakukan untuk memperoleh suhu dan waktu yang optimum dalam pembuatan arang serta mengetahui karakteristik arang yang dihasilkan pada suhu dan waktu optimumnya. Karakteristik arang mengacu pada SNI 06–3730-1995 dengan melakukan analisis terhadap kadar air, abu, volatile, dan karbon serta daya serapnya terhadap odine dan metilen biru. Suhu optimum pirolisis pembuatan arang adalah 300oC dengan karakteristik terbaik berupa rendemen, kadar air, volatile, abu, dan karbon berturut-turut sebesar 40,27 ±; 4,00 ± 0,00; 6,58 ± 0,07; 4,34 ± 1,22; dan 85,06%, serta daya serapnya terhadap iodin dan metilen biru sebesar 631,0935 ± 0,00 dan 131,34 ± 1,7 mg/g arang. Waktu pirolisis optimum adalah 90 menit dengan karakterisitik paling baik, yakni rendemen, kadar air, volatile, abu, dan karbon berturut-turut sebesar 42,30 ± 8,7; 2,00 ± 0,00; 2,87 ± 0,07; 9,68 ± 1,17; dan 85,44% serta daya serapnya terhadap iodin dan metilen biru sebesar 647,4642 ± 0,00 dan 136,20 ± 1,28 mg/g arang. Arang yang dihasilkan dari pirolisis pada suhu dan waktu optimum memiliki karakteristik yang sesuai dengan SNI 06-3730-1995 memiliki gugus fungsi O-H dan berupa karbon alifatik.   ABSTRACT: This paper discusses the manufacture and characterization of carbon made from the stems of marigold (Tagetes erecta at various temperatures and times of pyrolysis. This research aimed to obtain the optimum temperature and time of pyrolising in producing carbon, as well asto recognize the characteristics of the carbon produced. Characteristics of the carbon quality followed the Indonesian National Standard (SNI 06-3730-1995 by analyzing the contents of water, volatile substances, ash, and carbon, as well as, the ability of the carbon in absorption capacities of iodine and methylene blue. The optimum pyrolysis

  13. KARAKTERISASI LAPISAN PENYERAP DAPAT BAKAR PADA PERMUKAAN PELET UO2 + DOPAN TiO2

    Directory of Open Access Journals (Sweden)

    Sungkono Sungkono

    2017-01-01

    Full Text Available ABSTRAK KARAKTERISASI LAPISAN PENYERAP DAPAT BAKAR PADA PERMUKAAN PELET UO2 + DOPAN TiO2. Lapisan penyerap dapat bakar pada permukaan pelet UO2 + dopan TiO2 telah berhasil dibuat dengan menggunakan mertoda RF sputtering. Penelitian ini bertujuan untuk mendapatkan karakter mikrostruktur pelet UO2 + dopan, ketebalan, kekerasan mikro, komposisi kimia dan struktur kristal lapisan penyerap dapat bakar pada permukaan pelet UO2.  Penentuan mikrostruktur dan ketebalan lapisan dilakukan dengan menggunakan mikroskop optik, kekerasan lapisan dengan metode kekerasan mikro Vickers, komposisi kimia dengan spektrometri XRF dan struktur kristal dengan difraksi sinar-X. Hasil penelitian menunjukan bahwa semakin besar kandungan TiO2 dalam pelet maka semakin besar ukuran butir dalam mikrostruktur pelet dan semakin tebal lapisan yang terbentuk pada permukaan pelet UO2. Kekerasan lapisan permukaan pelet UO2 + dopan TiO2 sinter relatif sama dan tidak bergantung pada konsentrasi dopan TiO2. Lapisan permukaan pelet UO2 + 0,3 % TiO2, pelet UO2 + 0,5 % TiO2 dan pelet UO2 + 0,7 % TiO2 sinter mengandung unsur zirkonium masing-masing 1,97 mg, 2,47 mg dan 4,81 mg. Lapisan penyerap dapat bakar pada permukaan pelet UO2 + dopan TiO2 sinter mempunyai fasa ZrB2 dengan struktur kristal heksagonal. Kata Kunci: lapisan permukaan, penyerap dapat bakar, pelet UO2, mikrostruktur, kekerasan, komposisi kimia, struktur kristal. ABSTRACT CHARACTERIZATION OF BURNABLE ABSORBER LAYER ON THE SURFACE OF UO2 + DOPED TiO2 PELLETS. Burnable absorber layer on the surface of UO2 + doped TiO2 pellets have successfully created using RF sputtering methods. The objective of this research is to obtain of microstructure characters of UO2 + doped TiO2 pellets, thickness, micro hardness, chemical composition and crystal structure of burnable absorber layer on the surface of UO2 pellets. The methods used are the microstructure and layer thickness using optical microscopy, layer hardness with micro Vickers

  14. Molecular design of materials for cell separation.

    Science.gov (United States)

    Kataoka, K

    1988-12-01

    There has been a strong demand in biomedical sciences to isolate viable cell populations with high yield and purity. An important facet of this work was to develop new polymeric adsorbent for the separation of lymphocyte subpopulations. Based on our strategy of separating cells through their differential ionic affinity toward multiphase-structured adsorbent with ionically derivatized microdomains, a series of poly(2-hydroxyethyl methacrylate)/polyamine graft copolymers (HA copolymers) was prepared. HA copolymer columns were found to show specific adsorption affinity toward B lymphocytes, and allows for separation of B and T lymphocytes in high yield and purity with a short operating time. Separation mechanism involved in the resolution of B and T lymphocytes by HA copolymer column is discussed in this paper. Further, photo-induced desorption of cells from the adsorbent derivatized with photo-responsive functional group (azobenzene group) was demonstrated to emphasize the feasibility of photo-regulated chromatography as a novel tool in cell separation technology.

  15. 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...

  16. 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.

  17. Pemurnian Parsial dan Karakterisasi Enzim Xilanase dari Bakteri Laut Bacillus safencis strain LBF P20 Asal Pulau Pari Jakarta

    Directory of Open Access Journals (Sweden)

    Fitria Fitria

    2017-03-01

    Full Text Available Enzyme xylanase (EC 3.2.1.8 is widely used in various industrial  fields for the hydrolysis of xylan (hemicellulose into xylooligosaccharide and xylose. The aims of this study were to  conduct partial purification and characterization of xylanase from marine Bacillus safencis strain LBF P20 and to obtain the  xylooligosaccharide types from xylan hydrolysis by this enzyme.  Based on this research, the optimum time for enzyme production  occurred at 96 hours with the enzyme activity of 6.275 U/mL and  enzyme specific activity of 5.093 U/mg. The specific activities were  obtained from precipitation by amicon® ultra-15 centrifugal filter devices, gel filtration chromatography and anion exchange chromatography that were increased by 15.07, 34.7, and 96.0  U/mg. The results showed that the highest activity at pH 7, temperature of 60 °C, and stable at 4 °C. Type of  xylooligosaccharide produced by this study were xylohexoses, xylotriose, and xylobiose. SDS-PAGE analysis and zimogram  showed that the molecular weight of xylanase protein were about  25 kDa.   ABSTRAK Enzim xilanase (EC 3.2.1.8 digunakan dalam hidrolisis xilan  (hemiselulosa menjadi xilooligosakarida dan xilosa. Penelitian  ini bertujuan untuk melakukan purifikasi parsial dan karakterisasi xilanase dari bakteri laut Bacillus safencis strain LBF P20 serta uji  hidrolisis untuk mengetahui jenis xilooligosakarida yang  dihasilkan oleh enzim tersebut. Berdasarkan hasil penelitian, waktu optimum untuk produksi enzim terjadi pada jam ke 96  dengan aktivitas enzim sebesar 6,275 U/mL dan aktivitas spesifik enzim sebesar 5,093 (U/mg. Aktivitas spesifik enzim hasil  pemekatan dengan amicon® ultra-15 centrifugal filter devices,  kromatografi filtrasi gel dan kromatografi penukar anion  mengalami peningkatan berturut-turut sebesar 15,1; 34,7 dan96,0 U/mg. Hasil karakterisasi menunjukkan aktivitas  tertinggi pada pH 7, suhu 60 °C dan stabil pada suhu 4 °C. Analisis SDS

  18. Local Structure Analysis of Materials for Solar Cell Absorber Layer

    OpenAIRE

    Jewell, Leila Elizabeth

    2016-01-01

    This dissertation examines solar cell absorber materials that have the potential to replace silicon in solar cells, including several copper-based sulfides and perovskites. Earth-abundant absorbers such as these become even more cost-effective when used in a nanostructured solar cell. Atomic layer deposition (ALD) and chemical vapor deposition (CVD) deposit highly conformal films and hence are important tools for developing extremely thin absorber solar cells with scalability. Thus, the prima...

  19. Mechanics of Granular Materials (MGM) Test Cell

    Science.gov (United States)

    2004-01-01

    Test cells comprise specimen sand contained in a latex membrane (with a grid pattern for CCD cameras) between metal end plates and housed in a water-filled Lexan jacket. Experiment flown on STS-79 and STS-89. Principal Investigator: Dr. Stein Sture.

  20. 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

  1. FMIT test cell diagnostics: a unique materials challenge

    International Nuclear Information System (INIS)

    Cannon, C.P.; Fuller, J.L.

    1981-08-01

    Basic materials problems are discussed in instrumenting the FMIT test cell, which are applicable to fusion devices in general. Recent data on ceramic-to-metal seals, mineral insulated instrument cables, thermocouples, and optical components are reviewed. The data makes it clear that it would be a mistake to assume that materials and instruments will behave in the FMIT test cell environment as they do in more familiar fission reactors and low power accelerators

  2. New in-situ neutron diffraction cell for electrode materials

    OpenAIRE

    Biendicho, Jordi Jacas; Roberts, Matthew; Offer, Colin; Noréus, Dag; Widenkvist, Erika; Smith, Ronald I.; Svensson, Gunnar; Edström, Kristina; Norberg, Stefan T.; Eriksson, Sten G.; Hull, Stephen

    2014-01-01

    A novel neutron diffraction cell has been constructed to allow in-situ studies of the structural changes in materials of relevance to battery applications during charge/discharge cycling. The new design is based on the coin cell geometry, but has larger dimensions compared to typical commercial batteries in order to maximize the amount of electrode material and thus, collect diffraction data of good statistical quality within the shortest possible time. An important aspect of the design is it...

  3. 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.

  4. Dry storage cell for radioactive material

    International Nuclear Information System (INIS)

    Bradley, N.

    1982-01-01

    In a dry storage cell for irradiated nuclear fuel or other highly active waste, cooling air flow is by natural draught in heat exchange with fuel containing canisters housed in channels. To inhibit corrosion by ensuring that the temperature of the air flowing over the canisters does not fall below the dew point when heat generation by decay has fallen, a fraction of the heat energy transferred to the cooling air is recirculated to the air upstream of the canisters. Recirculation of heat energy is effected by recirculation of a fraction of the hot air from downstream of the canisters. (author)

  5. 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%.

  6. Development of new membrane materials for direct methanol fuel cells

    NARCIS (Netherlands)

    Yildirim, M.H.

    2009-01-01

    Development of new membrane materials for direct methanol fuel cells Direct methanol fuel cells (DMFCs) can convert the chemical energy of a fuel directly into electrical energy with high efficiency and low emission of pollutants. DMFCs can be used as the power sources to portable electronic devices

  7. 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.

  8. Synthesis of polymer materials for use as cell culture substrates

    Energy Technology Data Exchange (ETDEWEB)

    Lakard, Sophie [Laboratoire de Chimie des Materiaux et Interfaces, University of Franche-Comte, IUT, 30 Avenue de l' Observatoire, 25009 Besancon (France)], E-mail: sophie.lakard@univ-fcomte.fr; Morrand-Villeneuve, Nadege [Laboratoire de Neurosciences, University of Franche-Comte, Place Leclerc, 25030 Besancon (France); Lesniewska, Eric [Laboratoire de Physique de l' Universite de Bourgogne, University of Bourgogne, 9 Avenue Savary, 21078 Dijon (France); Lakard, Boris [Laboratoire de Chimie des Materiaux et Interfaces, University of Franche-Comte, 16 Route de Gray, 25030 Besancon (France); Michel, Germaine [Laboratoire de Neurosciences, University of Franche-Comte, Place Leclerc, 25030 Besancon (France); Herlem, Guillaume [Laboratoire de Chimie des Materiaux et Interfaces, University of Franche-Comte, 16 Route de Gray, 25030 Besancon (France); Gharbi, Tijani [Laboratoire d' Optique P.M. Duffieux, University of Franche-Comte, 16 Route de Gray, 25030 Besancon (France); Fahys, Bernard [Laboratoire de Chimie des Materiaux et Interfaces, University of Franche-Comte, 16 Route de Gray, 25030 Besancon (France)

    2007-12-20

    Up to today, several techniques have been used to maintain cells in culture for studying many aspects of cell biology and physiology. More often, cell culture is dependent on proper anchorage of cells to the growth surface. Thus, poly-L-lysine, fibronectin or laminin are the most commonly used substrates. In this study, electrosynthesized biocompatible polymer films are proposed as an alternative to these standard substrates. The electrosynthesized polymers tested were polyethylenimine, polypropylenimine and polypyrrole. Then, the adhesion, proliferation and morphology of rat neuronal cell lines were investigated on these polymer substrates in an attempt to develop new and efficient polymer materials for cell culture. During their growth on the polymers, the evolution of the cell morphology was monitored using both confocal microscopy and immunohistochemistry, leading to the conclusion of a normal development. An estimation of the adhesion and proliferation rates of rat neuronal cell cultures indicated that polyethylenimine and polypropylenimine were the best substrates for culturing olfactory neuronal cells. A method to favour the differentiation of the neuronal cells was also developed since the final aim of this work is to develop a biosensor for odour detection using differentiated neuronal cells as transducers. Consequently, a biosensor was microfabricated using silicon technology. This microsystem allowed us to culture the cells on a silicon wafer and to position the cells on certain parts of the silicon wafer.

  9. Harnessing cell-material interaction to control cell fate: design ...

    Indian Academy of Sciences (India)

    Physical (topography, stiffness) and chemical instructions encoded in the extracellular environment govern cell behaviour. Understanding these interactions as they operate in native extracellular matrix and capturing the complexity of the spatiotemporal presentation of multiple such signals in synthetic scaffolds is a key to ...

  10. Protective material for solar cell; Taiyo denchiyo hyomen hogozai

    Energy Technology Data Exchange (ETDEWEB)

    Iimura, M.; Domoto, T. [Nitto Denko Corp., Osaka (Japan)

    1998-02-03

    The protective material for the solar cell of this invention consists of fluororesin containing from 1 to 20wt% titanium oxide particles with the particle size range from 1 to 1,000nm. Surface contamination of the protective material for the solar cell and deterioration of the adhesive are prevented when titanium oxide with particular particle size is contained in the fluororesin in a particular range as mentioned above. Titanium oxide has photocatalytic performance to decompose organic substances, and the surface protective material for the solar cell containing titanium oxide can decompose and remove dirt such as dust adhering the surface for preventing surface contamination. In addition, total light permeability can be maintained at high rate and the permeability of less than 350nm ultraviolet rays causing deterioration of the adhesive can be decreased if the particle size and content of titanium oxide are specified. Titanium dioxide of anatase type crystal structure is ideal as the titanium oxide. 1 tab.

  11. Review on MIEC Cathode Materials for Solid Oxide Fuel Cells

    Science.gov (United States)

    Burnwal, Suman Kumar; Bharadwaj, S.; Kistaiah, P.

    2016-11-01

    The cathode is one of the most important components of solid oxide fuel cells (SOFCs). The reduction of oxygen at the cathode (traditional cathodes like LSM, LSGM, etc.) is the slow step in the cell reaction at intermediate temperature (600-800∘C) which is one of the key obstacles to the development of SOFCs. The mixed ionic and electronic conducting cathode (MIEC) like LSCF, BSCF, etc., has recently been proposed as a promising cathode material for SOFC due to the improvement of the kinetic of the cathode reaction. The MIEC materials provide not only the electrons for the reduction of oxygen, but also the ionic conduction required to ensure the transport of the formed oxygen ions and thereby improves the overall electrochemical performance of SOFC system. The characteristics of MIEC cathode materials and its comparison with other traditional cathode materials is studied and presented in the paper.

  12. 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.

  13. Cell-material interactions in tendon tissue engineering.

    Science.gov (United States)

    Lin, Junxin; Zhou, Wenyan; Han, Shan; Bunpetch, Varitsara; Zhao, Kun; Liu, Chaozhong; Yin, Zi; Ouyang, Hongwei

    2018-04-01

    The interplay between cells and materials is a fundamental topic in biomaterial-based tissue regeneration. One of the principles for biomaterial development in tendon regeneration is to stimulate tenogenic differentiation of stem cells. To this end, efforts have been made to optimize the physicochemical and bio-mechanical properties of biomaterials for tendon tissue engineering. However, recent progress indicated that innate immune cells, especially macrophages, can also respond to the material cues and undergo phenotypical changes, which will either facilitate or hinder tissue regeneration. This process has been, to some extent, neglected by traditional strategies and may partially explain the unsatisfactory outcomes of previous studies; thus, more researchers have turned their focus on developing and designing immunoregenerative biomaterials to enhance tendon regeneration. In this review, we will first summarize the effects of material cues on tenogenic differentiation and paracrine secretion of stem cells. A brief introduction will also be made on how material cues can be manipulated for the regeneration of tendon-to-bone interface. Then, we will discuss the characteristics and influences of macrophages on the repair process of tendon healing and how they respond to different materials cues. These principles may benefit the development of novel biomaterials provided with combinative bioactive cues to activate tenogenic differentiation of stem cells and pro-resolving macrophage phenotype. The progress achieved with the rapid development of biomaterial-based strategies for tendon regeneration has not yielded broad benefits to clinical patients. In addition to the interplay between stem cells and biomaterials, the innate immune response to biomaterials also plays a determinant role in tissue regeneration. Here, we propose that fine-tuning of stem cell behaviors and alternative activation of macrophages through material cues may lead to effective tendon

  14. Stem cell homing-based tissue engineering using bioactive materials

    Science.gov (United States)

    Yu, Yinxian; Sun, Binbin; Yi, Chengqing; Mo, Xiumei

    2017-06-01

    Tissue engineering focuses on repairing tissue and restoring tissue functions by employing three elements: scaffolds, cells and biochemical signals. In tissue engineering, bioactive material scaffolds have been used to cure tissue and organ defects with stem cell-based therapies being one of the best documented approaches. In the review, different biomaterials which are used in several methods to fabricate tissue engineering scaffolds were explained and show good properties (biocompatibility, biodegradability, and mechanical properties etc.) for cell migration and infiltration. Stem cell homing is a recruitment process for inducing the migration of the systemically transplanted cells, or host cells, to defect sites. The mechanisms and modes of stem cell homing-based tissue engineering can be divided into two types depending on the source of the stem cells: endogenous and exogenous. Exogenous stem cell-based bioactive scaffolds have the challenge of long-term culturing in vitro and for endogenous stem cells the biochemical signal homing recruitment mechanism is not clear yet. Although the stem cell homing-based bioactive scaffolds are attractive candidates for tissue defect therapies, based on in vitro studies and animal tests, there is still a long way before clinical application.

  15. Directing neuronal cell growth on implant material surfaces by microstructuring.

    OpenAIRE

    Reich, Uta; Fadeeva, Elena; Warnecke, Athanasia; Paasche, Gerrit; Müller, Peter; Chichkov, Boris; Stöver, Timo; Lenarz, Thomas; Reuter, Günter

    2012-01-01

    For best hearing sensation, electrodes of auditory prosthesis must have an optimal electrical contact to the respective neuronal cells. To improve the electrode-nerve interface, microstructuring of implant surfaces could guide neuronal cells toward the electrode contact. To this end, femtosecond laser ablation was used to generate linear microgrooves on the two currently relevant cochlear implant materials, silicone elastomer and platinum. Silicone surfaces were structured by two different me...

  16. 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.

  17. Perovskite-Based Solar Cells: Materials, Methods, and Future Perspectives

    Directory of Open Access Journals (Sweden)

    Di Zhou

    2018-01-01

    Full Text Available A novel all-solid-state, hybrid solar cell based on organic-inorganic metal halide perovskite (CH3NH3PbX3 materials has attracted great attention from the researchers all over the world and is considered to be one of the top 10 scientific breakthroughs in 2013. The perovskite materials can be used not only as light-absorbing layer, but also as an electron/hole transport layer due to the advantages of its high extinction coefficient, high charge mobility, long carrier lifetime, and long carrier diffusion distance. The photoelectric power conversion efficiency of the perovskite solar cells has increased from 3.8% in 2009 to 22.1% in 2016, making perovskite solar cells the best potential candidate for the new generation of solar cells to replace traditional silicon solar cells in the future. In this paper, we introduce the development and mechanism of perovskite solar cells, describe the specific function of each layer, and focus on the improvement in the function of such layers and its influence on the cell performance. Next, the synthesis methods of the perovskite light-absorbing layer and the performance characteristics are discussed. Finally, the challenges and prospects for the development of perovskite solar cells are also briefly presented.

  18. 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.

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

    Science.gov (United States)

    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.

  20. 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

  1. Sandwich-like Microenvironments to Harness Cell/Material Interactions

    Science.gov (United States)

    Ballester-Beltrán, José; Lebourg, Myriam; Salmerón-Sánchez, Manuel

    2015-01-01

    Cell culture has been traditionally carried out on bi-dimensional (2D) substrates where cells adhere using ventral receptors to the biomaterial surface. However in vivo, most of the cells are completely surrounded by the extracellular matrix (ECM), resulting in a three-dimensional (3D) distribution of receptors. This may trigger differences in the outside-in signaling pathways and thus in cell behavior. This article shows that stimulating the dorsal receptors of cells already adhered to a 2D substrate by overlaying a film of a new material (a sandwich-like culture) triggers important changes with respect to standard 2D cultures. Furthermore, the simultaneous excitation of ventral and dorsal receptors shifts cell behavior closer to that found in 3D environments. Additionally, due to the nature of the system, a sandwich-like culture is a versatile tool that allows the study of different parameters in cell/material interactions, e.g., topography, stiffness and different protein coatings at both the ventral and dorsal sides. Finally, since sandwich-like cultures are based on 2D substrates, several analysis procedures already developed for standard 2D cultures can be used normally, overcoming more complex procedures needed for 3D systems. PMID:26274867

  2. Directing neuronal cell growth on implant material surfaces by microstructuring.

    Science.gov (United States)

    Reich, Uta; Fadeeva, Elena; Warnecke, Athanasia; Paasche, Gerrit; Müller, Peter; Chichkov, Boris; Stöver, Timo; Lenarz, Thomas; Reuter, Günter

    2012-05-01

    For best hearing sensation, electrodes of auditory prosthesis must have an optimal electrical contact to the respective neuronal cells. To improve the electrode-nerve interface, microstructuring of implant surfaces could guide neuronal cells toward the electrode contact. To this end, femtosecond laser ablation was used to generate linear microgrooves on the two currently relevant cochlear implant materials, silicone elastomer and platinum. Silicone surfaces were structured by two different methods, either directly, by laser ablation or indirectly, by imprinting using laser-microstructured molds. The influence of surface structuring on neurite outgrowth was investigated utilizing a neuronal-like cell line and primary auditory neurons. The pheochromocytoma cell line PC-12 and primary spiral ganglion cells were cultured on microstructured auditory implant materials. The orientation of neurite outgrowth relative to the microgrooves was determined. Both cell types showed a preferred orientation in parallel to the microstructures on both, platinum and on molded silicone elastomer. Interestingly, microstructures generated by direct laser ablation of silicone did not influence the orientation of either cell type. This shows that differences in the manufacturing procedures can affect the ability of microstructured implant surfaces to guide the growth of neurites. This is of particular importance for clinical applications, since the molding technique represents a reproducible, economic, and commercially feasible manufacturing procedure for the microstructured silicone surfaces of medical implants. Copyright © 2012 Wiley Periodicals, Inc.

  3. 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.

  4. Advances in Materials and System Technology for Portable Fuel Cells

    Science.gov (United States)

    Narayanan, Sekharipuram R.

    2007-01-01

    This viewgraph presentation describes the materials and systems engineering used for portable fuel cells. The contents include: 1) Portable Power; 2) Technology Solution; 3) Portable Hydrogen Systems; 4) Direct Methanol Fuel Cell; 5) Direct Methanol Fuel Cell System Concept; 6) Overview of DMFC R&D at JPL; 7) 300-Watt Portable Fuel Cell for Army Applications; 8) DMFC units from Smart Fuel Cell Inc, Germany; 9) DMFC Status and Prospects; 10) Challenges; 11) Rapid Screening of Well-Controlled Catalyst Compositions; 12) Screening of Ni-Zr-Pt-Ru alloys; 13) Issues with New Membranes; 14) Membranes With Reduced Methanol Crossover; 15) Stacks; 16) Hybrid DMFC System; 17) Small Compact Systems; 18) Durability; and 19) Stack and System Parameters for Various Applications.

  5. Emerging Semitransparent Solar Cells: Materials and Device Design.

    Science.gov (United States)

    Tai, Qidong; Yan, Feng

    2017-09-01

    Semitransparent solar cells can provide not only efficient power-generation but also appealing images and show promising applications in building integrated photovoltaics, wearable electronics, photovoltaic vehicles and so forth in the future. Such devices have been successfully realized by incorporating transparent electrodes in new generation low-cost solar cells, including organic solar cells (OSCs), dye-sensitized solar cells (DSCs) and organometal halide perovskite solar cells (PSCs). In this review, the advances in the preparation of semitransparent OSCs, DSCs, and PSCs are summarized, focusing on the top transparent electrode materials and device designs, which are all crucial to the performance of these devices. Techniques for optimizing the efficiency, color and transparency of the devices are addressed in detail. Finally, a summary of the research field and an outlook into the future development in this area are provided. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Interfacial Materials for Organic Solar Cells: Recent Advances and Perspectives.

    Science.gov (United States)

    Yin, Zhigang; Wei, Jiajun; Zheng, Qingdong

    2016-08-01

    Organic solar cells (OSCs) have shown great promise as low-cost photovoltaic devices for solar energy conversion over the past decade. Interfacial engineering provides a powerful strategy to enhance efficiency and stability of OSCs. With the rapid advances of interface layer materials and active layer materials, power conversion efficiencies (PCEs) of both single-junction and tandem OSCs have exceeded a landmark value of 10%. This review summarizes the latest advances in interfacial layers for single-junction and tandem OSCs. Electron or hole transporting materials, including metal oxides, polymers/small-molecules, metals and metal salts/complexes, carbon-based materials, organic-inorganic hybrids/composites, and other emerging materials, are systemically presented as cathode and anode interface layers for high performance OSCs. Meanwhile, incorporating these electron-transporting and hole-transporting layer materials as building blocks, a variety of interconnecting layers for conventional or inverted tandem OSCs are comprehensively discussed, along with their functions to bridge the difference between adjacent subcells. By analyzing the structure-property relationships of various interfacial materials, the important design rules for such materials towards high efficiency and stable OSCs are highlighted. Finally, we present a brief summary as well as some perspectives to help researchers understand the current challenges and opportunities in this emerging area of research.

  7. Graphene - a promising material for organic photovoltaic cells.

    Science.gov (United States)

    Wan, Xiangjian; Long, Guankui; Huang, Lu; Chen, Yongsheng

    2011-12-01

    As a promising two-dimensional nanomaterial with outstanding electronic, optical, thermal, and mechanical properties, graphene has been proposed for many applications. In this Progress Report we summarize and discuss comprehensively the advances made so far for applications of graphene in organic photovoltaic (OPV) cells, including that for transparent electrodes, active layers and interfaces layer in OPV. It is concluded that graphene may very likely play a major role in new developments/improvements in OPVs. The future studies for this area are proposed to focus on the following: i) improving the conductivity without comprising the transparency as a transparent electrode material; ii) controlling the sheet sizes, band structure and surface morphology for use as a electron acceptor material, and iii) controlling and improving the functionalization and compatibility with other materials as interface layer material. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Karakterisasi Paduan AlMgSi Untuk Kelongsong Bahan Bakar U3Si2/Al Dengan Densitas Uranium 5,2 gU/cm3

    Directory of Open Access Journals (Sweden)

    Aslina Br. Ginting

    2018-03-01

    Full Text Available Meningkatnya densitas uranium dari 2,96 gU/cm3 menjadi 5,2 gU/cm3 bahan bakar U3Si2/Al harus diikuti dengan penggunaan kelongsong yang kompatibel. Bahan bakar berdensitas tinggi mempunyai kekerasan yang tinggi, sehingga bila menggunakan paduan AlMg2 sebagai kelongsong dapat menyebabkan terjadi dogbone pada saat perolan. Selain fenomena dogbone, pada saat bahan bakar tersebut digunakan di reaktor dapat terjadi swelling karena meningkatnya hasil fisi maupun burn up. Oleh karena itu, perlu dicari pengganti bahan kelongsong untuk bahan bakar U3Si2/Al densitas tinggi. Pada penelitian ini telah dilakukan karakterisasi paduan AlMgSi sebagai kandidat pengganti kelongsong AlMg2. Karakterisasi yang dilakukan meliputi analisis termal, kekerasan, mikrostruktur dan laju korosi. Analisis termal dilakukan menggunakan DTA (Differential Thermal Analysis dan DSC (Differential Scanning Calorimetry. Analisis kekerasan menggunakan alat uji kekerasan mikro, mikrostruktur menggunakan SEM (Scanning Electron Microscope dan analisis laju korosi dilakukan dengan pemanasan pada temperatur 150 oC selama 77 jam di dalam autoclave. Hasil analisis menunjukkan bahwa kelongsong AlMgSi maupun AlMg2 mempunyai kompatibilitas panas dengan bahan bakar U3Si2/Al cukup stabil hingga temperatur 650 oC. Kelongsong AlMgSi mempunyai kekerasan sebesar 115 HVN dan kelongsong AlMg2 sebesar 70,1 HVN. Sementara itu, analisis mikrostruktur menunjukkan bahwa morfologi ikatan antarmuka (interface bonding kelongsong AlMgSi lebih baik dari kelongsong AlMg2, demikian halnya dengan laju korosi bahwa kelongsong AlMgSi mempunyai laju korosi lebih kecil dibanding kelongsong AlMg2. Hasil karakterisasi termal, kekerasan, mikrostruktur dan laju korosi menunjukkan bahwa PEB U3Si2/Al densitas 5,2 gU/cm3 menggunakan kelongsong AlMgSi lebih baik dibanding PEB U3Si2/Al  densitas 5,2 gU/cm3  menggunakan kelongsong AlMg2. Kata kunci: U3Si2/Al, densitas 5,2 gU/cm3, kelongsong AlMgSi dan AlMg2.

  9. Analisis Hasil Sintesis Serbuk TiO2 / ZnO sebagai Lapisan Elektroda untuk Aplikasi Dye-sensitized Solar Cell

    Directory of Open Access Journals (Sweden)

    Lilis Retnaningsih

    2016-06-01

    Full Text Available Pada penelitian ini telah dilakukan sintesis antara serbuk partikel nano TiO2 dan serbuk partikel nano ZnO menjadi pasta yang akan diaplikasikan sebagai elektroda pada dye-sensitized solar cell (DSSC. Elektroda pada DSSC ini bekerja berdasarkan adsorbsi foton oleh pewarna, elektron yang tereksitasi ditransfer ke TiO2/ZnO yang mempunyai perbandingan berbeda. Dimensi material partikel nano TiO2/ZnO sebagai elektroda sangat penting untuk menghasilkan efisiensi yang lebih tinggi pada DSSC. Sifat ini sangat dipengaruh oleh metoda pabrikasi elektroda TiO2/ZnO dan parameternya. Pada penelitian ini digunakan metoda doctor blade untuk pabrikasi DSSC dan larutan dyes (Z907 sebagai zat pewarna. Tujuan penelitian ini adalah untuk mengetahui pengaruh pencampuran serbuk TiO2 dan serbuk ZnO sebagai elektroda. Teknik pembuatan pasta TiO2/ZnO sebagai elektroda sangat penting untuk menghasilkan efisiensi tinggi pada DSSC. Teknik ini sangat terkait dengan material TiO2/ZnO, metoda pabrikasi, dan parameter pengukurannya. Dalam penelitian ini dibahas hasil karakterisasi XRD pada kedua serbuk TiO2 dan ZnO, hasil SEM pada pencampuran kedua material, hasil pengujian IPCE serta hasil pengukuran effisiensi pada pengujian I - V.

  10. 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.

  11. Materials System for Intermediate Temperature Solid Oxide Fuel Cell

    Energy Technology Data Exchange (ETDEWEB)

    Uday B. Pal; Srikanth Gopalan

    2006-01-12

    The objective of this work was to obtain a stable materials system for intermediate temperature solid oxide fuel cell (SOFC) capable of operating between 600-800 C with a power density greater than 0.2 W/cm{sup 2}. The solid electrolyte chosen for this system was La{sub 0.9}Sr{sub 0.1}Ga{sub 0.8}Mg{sub 0.2}O{sub 3}, (LSGM). To select the right electrode materials from a group of possible candidate materials, AC complex impedance spectroscopy studies were conducted between 600-800 C on symmetrical cells that employed the LSGM electrolyte. Based on the results of the investigation, LSGM electrolyte supported SOFCs were fabricated with La{sub 0.6}Sr{sub 0.4}Co{sub 0.8}Fe{sub 0.2}O{sub 3}-La{sub 0.9}Sr{sub 0.1}Ga{sub 0.8}Mg{sub 0.2}O{sub 3} (LSCF-LSGM) composite cathode and Nickel-Ce{sub 0.6}La{sub 0.4}O{sub 3} (Ni-LDC) composite anode having a barrier layer of Ce{sub 0.6}La{sub 0.4}O{sub 3} (LDC) between the LSGM electrolyte and the Ni-LDC anode. Electrical performance and stability of these cells were determined and the electrode polarization behavior as a function of cell current was modeled between 600-800 C. The electrical performance of the anode-supported SOFC was simulated assuming an electrode polarization behavior identical to the LSGM-electrolyte-supported SOFC. The simulated electrical performance indicated that the selected material system would provide a stable cell capable of operating between 600-800 C with a power density between 0.2 to 1 W/cm{sup 2}.

  12. Proton Conducting Fuel Cells where Electrochemistry Meets Material Science

    DEFF Research Database (Denmark)

    Li, Qingfeng

    Fuel cells are electrochemical devices which directly convert the chemical energy of fuels into electrical energy. They are featured of high energy conversion efficiency and minimized pollutant emission. Proton conducting electrolytes are primarily used as separator materials for low and intermed...... science point of view including novel proton conducting materials and non-precious metal catalysts. The discussion will be made with highlights of DTU´s recent research and of course addressing a diverse technical audience.......Fuel cells are electrochemical devices which directly convert the chemical energy of fuels into electrical energy. They are featured of high energy conversion efficiency and minimized pollutant emission. Proton conducting electrolytes are primarily used as separator materials for low...... followed by a review of the state-of-the-art in terms of performance, lifetime and cost. Technically faced challenges are then outlined on a system level and traced back to fundamental issues of the proton conducting mechanisms and materials. Perspectives and future research are sketched from a materials...

  13. Solar cell structure incorporating a novel single crystal silicon material

    Science.gov (United States)

    Pankove, Jacques I.; Wu, Chung P.

    1983-01-01

    A novel hydrogen rich single crystal silicon material having a band gap energy greater than 1.1 eV can be fabricated by forming an amorphous region of graded crystallinity in a body of single crystalline silicon and thereafter contacting the region with atomic hydrogen followed by pulsed laser annealing at a sufficient power and for a sufficient duration to recrystallize the region into single crystal silicon without out-gassing the hydrogen. The new material can be used to fabricate semiconductor devices such as single crystal silicon solar cells with surface window regions having a greater band gap energy than that of single crystal silicon without hydrogen.

  14. GaSb-related materials for TPV cells

    Science.gov (United States)

    Mauk, M. G.; Andreev, V. M.

    2003-05-01

    A survey of materials options and technologies for GaSb-related thermophotovoltaic (TPV) cells is presented, followed by an overview of device design principles and issues. This device technology has been developed for thermal-to-electric generator systems with thermal emitter infrared sources operated in the 1000-1200 °C range. Significant results for the growth, material characterization and device performance of TPV cells based on InGaAsSb, InGaSb, AlGaAsSb and InAsSbP fabricated by LPE, MOCVD, MBE and diffusion methods are reviewed. For single-junction TPV cells, epitaxial heterostructures with a ~0.53 eV bandgap InGaAsSb base layer and wide-bandgap AlGaAsSb or GaSb window/cladding layers (all closely lattice matched to a GaSb substrate) represent the state of the art. As an alternative, a low-cost Zn-diffusion technology for fabrication of InGaAsSb p-n homojunction structures has been developed for producing the high efficiency TPV cells. External quantum yields as high as 90% at wavelengths (around 2000 nm wavelength), and response edges to about 2400 nm wavelength have been obtained with these TPV cells. Multijunction tandem TPV devices based on GaSb top cells and InGaAsSb bottom cells provide even higher performance. TPV cells based on InAsSbP, also reviewed here, have spectral responses in wavelengths in the 2.5-3.5 mum range, and thus provide a means for utilizing radiation from thermal emitters with lower temperatures.

  15. How the relative permittivity of solar cell materials influences solar cell performance

    DEFF Research Database (Denmark)

    Crovetto, Andrea; Huss-Hansen, Mathias K.; Hansen, Ole

    2017-01-01

    The relative permittivity of the materials constituting heterojunction solar cells is usually not considered as a design parameter when searching for novel combinations of heterojunction materials. In this work, we investigate the validity of such an approach. Specifically, we show the effect...... of the materials permittivity on the physics and performance of the solar cell by means of numerical simulation supported by analytical relations. We demonstrate that, depending on the specific solar cell configuration and materials properties, there are scenarios where the relative permittivity has a major...... the heterojunction partner has a high permittivity, solar cells are consistently more robust against several non-idealities that are especially likely to occur in early-stage development, when the device is not yet optimized....

  16. Material and Device Stability in Perovskite Solar Cells.

    Science.gov (United States)

    Kim, Hui-Seon; Seo, Ja-Young; Park, Nam-Gyu

    2016-09-22

    Organic-inorganic halide perovskite solar cells have attracted great attention because of their superb efficiency reaching 22 % and low-cost, facile fabrication processing. Nevertheless, stability issues in perovskite solar cells seem to block further advancements toward commercialization. Thus, device stability is one of the important topics in perovskite solar cell research. In the beginning, the poor moisture resistivity of the perovskite layer was considered as a main problem that hindered further development of perovskite solar cells, which encouraged engineering of the perovskite or protection of the perovskite by a buffer layer. Soon after, other parameters affecting long-term stability were sequentially found and various attempts have been made to enhance intrinsic and extrinsic stability. Here we review the recent progresses addressing stability issues in perovskite solar cells. In this report, we investigated factors affecting stability from material and device points of view. To gain a better understanding of the stability of the bulk perovskite material, decomposition mechanisms were investigated in relation to moisture, photons, and heat. Stability of full device should also be carefully examined because its stability is dependent not only on bulk perovskite but also on the interfaces and selective contacts. In addition, ion migration and current-voltage hysteresis were found to be closely related to stability. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Novel materials for fuel cells operating on liquid fuels

    Directory of Open Access Journals (Sweden)

    César A. C. Sequeira

    2017-05-01

    Full Text Available Towards commercialization of fuel cell products in the coming years, the fuel cell systems are being redefined by means of lowering costs of basic elements, such as electrolytes and membranes, electrode and catalyst materials, as well as of increasing power density and long-term stability. Among different kinds of fuel cells, low-temperature polymer electrolyte membrane fuel cells (PEMFCs are of major importance, but their problems related to hydrogen storage and distribution are forcing the development of liquid fuels such as methanol, ethanol, sodium borohydride and ammonia. In respect to hydrogen, methanol is cheaper, easier to handle, transport and store, and has a high theoretical energy density. The second most studied liquid fuel is ethanol, but it is necessary to note that the highest theoretically energy conversion efficiency should be reached in a cell operating on sodium borohydride alkaline solution. It is clear that proper solutions need to be developed, by using novel catalysts, namely nanostructured single phase and composite materials, oxidant enrichment technologies and catalytic activity increasing. In this paper these main directions will be considered.

  18. 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...

  19. Microbial fuel cells: recent developments in design and materials

    Science.gov (United States)

    Bhargavi, G.; Venu, V.; Renganathan, S.

    2018-03-01

    Microbial Fuel Cells (MFCs) are the promising devices which can produce electricity by anaerobic fermentation of organic / inorganic matter from easily metabolized biomass to complex wastewater using microbes as biocatalysts. MFC technology has been found as a potential technology for electricity generation and concomitant wastewater treatment. However, the high cost of the components and low efficiency are barricading the commercialization of MFC when compared with other energy generating systems. The performance of an MFC is largely relying on the reactor design and electrode materials. On the way to improve the efficiency of an MFC, tremendous exercises have been carried out to explore new electrode materials and reactor designs in recent decades. The current review is excogitated to amass the progress in design and electrode materials, which could bolster further investigations on MFCs to improve their performance, mitigate the cost and successful implementation of technology in field applications as well.

  20. The use of graphene based materials for fuel cell, photovoltaics, and supercapacitor electrode materials

    Science.gov (United States)

    Tsang, Alpha C. H.; Kwok, Holly Y. H.; Leung, Dennis Y. C.

    2017-05-01

    This manuscript presents the methodology of the production of 2D and 3D graphene based material, and their applications in fuel cell, supercapacitor, and photovoltic in recent years. Due to the uniqueness and attractive properties of graphene nanosheets, a large number of techniques have been developed for raw graphene preparation, from a chemical method to a physical deposition of carbon vapor under extreme conditions. A variety of graphene based materials were also prepared from raw graphene or graphene oxide, including the metal loaded, metal oxides loaded, to the foreign elements doped graphene. Both two-dimensional (2D) to three-dimensional (3D) structured graphene were covered. These materials included the bulk or template hybrid composite, containing graphene hydrogel, graphene aerogel, or graphene foam and its derived products. They were widely used in green energy device research, which exhibited strong activity, and developed some special usage in recent research.

  1. Single material solar cells: the next frontier for organic photovoltaics?

    Energy Technology Data Exchange (ETDEWEB)

    Roncali, Jean [Group Linear Conjugated Systems, CNRS, Moltech-Anjou, UMR 6200, University of Angers, 2 Bd Lavoisier 49045 Angers (France)

    2011-03-18

    An overview of various approaches for the realization of single-material organic solar cells (SMOCs) is presented. Fullerene-conjugated systems dyads, di-block copolymers, and self-organized donor-acceptor molecules all represent different possible approaches towards SMOCs. Although each of them presents specific advantages and poses specific problems of design and synthesis, these different routes have witnessed significant progress in the past few years and SMOCs with efficiencies in the range of 1.50% have been realized. These performances are already higher than those of bi-component bulk heterojunction solar cells some ten years ago, demonstrating that SMOCs can represent a credible approach towards efficient and simple organic solar cells. Possible directions for future research are discussed with the aim of stimulating further research on this exciting topic. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. 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.

  3. 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

  4. 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.

  5. Pembuatan Dan Karakterisasi Gigi Tiruan Berbahan Dasar Komposit Resin Akrilik No.3 Dengan Penambahan Serat Kaca

    OpenAIRE

    Sinabutar, Yosephin Romania

    2013-01-01

    Acrylic resins usually used as a base for the manufacture of artificial teeth, because it is biocompatibel, flexible, and easily available material and cheap. This material is brittle and can cause pores due to evaporation of unreacted monomers to polymers. The advantages of this material resembles the original tooth, fit and aesthetics can be strengthened with the addition of glass fibers. In this research, the manufacture of denture acrylic resin-based thermal polymerization no.3 with the a...

  6. Hibiscus fiber carbon for fuel cell device material

    International Nuclear Information System (INIS)

    Nanik Indayaningsih; Anne Zulfia; Dedi Priadi; Suprapedi

    2010-01-01

    The objective of this research is carbon of hibiscus fibers for the application as basic material of fuel cell device. The carbon is made using a pyrolysis process in inert gas (nitrogen) for 1 hour at temperature of 500 °C, 700 °C and 900 °C. The X-Ray Diffractometer (XRD), Scanning Electron Microscope (SEM) and Impedance-Capacitance-Resistance-meter are used to find out the microstructure, morphology and electrical properties respectively. The results of the experiment showed that the carbon had a structure of amorphous, and as the semiconductor material the electrical conductivity was 5 x 10 -5 S.cm -1 to 4.9 x 10 -5 S.cm -1 increasing in accordance with the pyrolysis temperature. The morphology resembled to plaited mats constructed by porous fibers having width of 50 µm to 300 µm, thickness of 25 µm to 35 µm, and the porous size of 0.5 µm to 5 µm. This morphology enables carbon to be applied as a candidate for a basic material of the Proton Exchange Membrane Fuel Cell. (author)

  7. Emerging of Inorganic Hole Transporting Materials For Perovskite Solar Cells.

    Science.gov (United States)

    Rajeswari, Ramireddy; Mrinalini, Madoori; Prasanthkumar, Seelam; Giribabu, Lingamallu

    2017-07-01

    Hole transporting material (HTM) is a significant component to achieve the high performance perovskite solar cells (PSCs). Over the years, inorganic, organic and hybrid (organic-inorganic) material based HTMs have been developed and investigated successfully. Today, perovskite solar cells achieved the efficiency of 22.1 % with with 2,2',7,7'-tetrakis(N,N-di-p-methoxyphenyl-amine) 9,9-spirobifluorene (spiro-OMeTAD) as HTM. Nevertheless, synthesis and cost of organic HTMs is a major challenging issue and therefore alternative materials are required. From the past few years, inorganic HTMs showed large improvement in power conversion efficiency (PCE) and stability. Recently CuO x reached the PCE of 19.0% with better stability. These developments affirms that inorganic HTMs are better alternativesto the organic HTMs for next generation PSCs. In this report, we mainly focussed on the recent advances of inorganic and hybrid HTMs for PSCs and highlighted the efficiency and stability of PSCs improved by changing metal oxides as HTMs. Consequently, we expect that energy levels of these inorganic HTMs matches very well with the valence band of perovskites and improved efficiency helps in future practical deployment of low cost PSCs. © 2017 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Optimized designs and materials for nanostructure based solar cells

    Science.gov (United States)

    Shao, Qinghui

    Nanostructure-based solar cells are attracting significant attention as possible candidates for drastic improvement in photovoltaic (PV) energy conversion efficiency. Although such solar cells are expected to be more expensive there is growing need for the efficient and light-weight solar cells in aero-space and related industries. In this dissertation I present results of the theoretical, computational and experimental investigation of novel designs for quantum dot superlattice (QDS) based PV elements and advanced materials for transparent solar cells. In the first part of the dissertation I describe possible implementation of the intermediate-band (IB) solar cells with QDS. The IB cells were predicted to have PV efficiency exceeding the Shockley-Queisser limit for a single junction cell. The parameters of QDS structure have to be carefully tuned to achieve the desired charge carrier dispersion required for the IB operation. The first-principles models were used to calculate the electrical properties and light absorption in QDS. This approach allowed me to determine the dimensions of QDS for inducing the mini-band which plays the role of the IB. Using the detailed balance theory it was determined that the upper-bound PV efficiency of such IB solar cells can be as high as ˜51%. The required QDS dimensions on the basis of InAsN/GaAsSb are technologically challenging but feasible: ˜2-6 nm. Using the developed simulation tools I proposed several possible designs of QDS solar cells including one, which combined the benefits of the IB concept and the advanced tandem cell design. The second part of the dissertation presents a study of graphene layers as transparent electrodes for the PV cells. The graphene layers were mechanically exfoliated from bulk graphite and characterized with micro-Raman spectroscopy. It was found that graphene electrodes have good electrical conductivity, which reveals unusual temperature dependence beneficial for the proposed application. The

  9. Functional mesoporous materials for energy applications: solar cells, fuel cells, and batteries.

    Science.gov (United States)

    Ye, Youngjin; Jo, Changshin; Jeong, Inyoung; Lee, Jinwoo

    2013-06-07

    This feature article presents recent progress made in the synthesis of functional ordered mesoporous materials and their application as high performance electrodes in dye-sensitized solar cells (DSCs) and quantum dot-sensitized solar cells (QDSCs), fuel cells, and Li-ion batteries. Ordered mesoporous materials have been mainly synthesized using two representative synthetic methods: the soft template and hard template methods. To overcome the limitations of these two methods, a new method called CASH was suggested. The CASH method combines the advantages of the soft and hard template methods by employing a diblock copolymer, PI-b-PEO, which contains a hydrophilic block and an sp(2)-hybridized-carbon-containing hydrophobic block as a structure-directing agent. After discussing general techniques used in the synthesis of mesoporous materials, this article presents recent applications of mesoporous materials as electrodes in DSCs and QDSCs, fuel cells, and Li-ion batteries. The role of material properties and mesostructures in device performance is discussed in each case. The developed soft and hard template methods, along with the CASH method, allow control of the pore size, wall composition, and pore structure, providing insight into material design and optimization for better electrode performances in these types of energy conversion devices. This paper concludes with an outlook on future research directions to enable breakthroughs and overcome current limitations in this field.

  10. Resilient Sealing Materials for Solid Oxide Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Signo T. Reis; Richard K. Brow

    2006-09-30

    This report describes the development of ''invert'' glass compositions designed for hermetic seals in solid oxide fuel cells (SOFC). Upon sealing at temperatures compatible with other SOFC materials (generally {le}900 C), these glasses transform to glass-ceramics with desirable thermo-mechanical properties, including coefficients of thermal expansion (CTE) over 11 x 10{sup -6}/C. The long-term (>four months) stability of CTE under SOFC operational conditions (e.g., 800 C in wet forming gas or in air) has been evaluated, as have weight losses under similar conditions. The dependence of sealant properties on glass composition are described in this report, as are experiments to develop glass-matrix composites by adding second phases, including Ni and YSZ. This information provides design-guidance to produce desirable sealing materials.

  11. 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.

  12. Self assembling bioactive materials for cell adhesion in tissue repair

    Science.gov (United States)

    Hwang, Julia J.

    This work involved the study of biodegradable and biocompatible materials that have the potential to modify tissue engineering scaffolds through self assembly, generating multiple layers that deliver bioactivity. Diblock biomaterials containing cholesteryl moieties and oligomers of lactic acid units were found to form single crystals when precipitated from hot ethanol and smectic liquid crystalline phases when cast as a film. Cell culture experiments on these films with 3T3 and 3T6 fibroblasts indicated that these ordered materials form surfaces with specific chemistries that favored cell adhesion, spreading, and proliferation suggesting the potential of mediating human tissue repair. The author believes the cholesteryl moieties found on the surface play a key role in determining cell behavior. Cholesteryl-(L-lactic acid) diblock molecules were then functionalized with moieties including vitamin Bx, cholesterol, and the anti-inflammatory drug indomethacin. An unstable activated ester between indomethacin and the diblock molecule resulted in the release of indomethacin into the culture medium which inhibited the proliferation of 3T3 fibroblasts. Finally, a series of molecules were designed to incorporate dendrons based on amino acids at the termini of the diblock structures. It was determined that lysine, a basic amino acid, covalently coupled to cholesteryl-(L-lactic acid) can promote cell adhesion and spreading while negatively charged and zwitterionic 2nd generation dendrons based on aspartic acid do not. Incorporation of the well known arginine-glycine-aspartic acid (RGD) sequence, which is found in many adhesive proteins, to the dendrons imparted integrin-mediated cell adhesion as evidenced by the formation of stress fibers. We also explored the capacity of integrin receptors to bind to ligands that are not the linear form of RGD, but have R, G, and D spatially positioned to mimic the linear RGD environments. For this purpose, the arms of the 2 nd generation

  13. Principles and Materials Aspects of Direct Alkaline Alcohol Fuel Cells

    Directory of Open Access Journals (Sweden)

    Eileen Hao Yu

    2010-08-01

    Full Text Available Direct alkaline alcohol fuel cells (DAAFCs have attracted increasing interest over the past decade because of their favourable reaction kinetics in alkaline media, higher energy densities achievable and the easy handling of the liquid fuels. In this review, principles and mechanisms of DAAFCs in alcohol oxidation and oxygen reduction are discussed. Despite the high energy densities available during the oxidation of polycarbon alcohols they are difficult to oxidise. Apart from methanol, the complete oxidation of other polycarbon alcohols to CO2 has not been achieved with current catalysts. Different types of catalysts, from conventional precious metal catalyst of Pt and Pt alloys to other lower cost Pd, Au and Ag metal catalysts are compared. Non precious metal catalysts, and lanthanum, strontium oxides and perovskite-type oxides are also discussed. Membranes like the ones used as polymer electrolytes and developed for DAAFCs are reviewed. Unlike conventional proton exchange membrane fuel cells, anion exchange membranes are used in present DAAFCs. Fuel cell performance with DAAFCs using different alcohols, catalysts and membranes, as well as operating parameters are summarised. In order to improve the power output of the DAAFCs, further developments in catalysts, membrane materials and fuel cell systems are essential.

  14. Drop detachment and motion on fuel cell electrode materials.

    Science.gov (United States)

    Gauthier, Eric; Hellstern, Thomas; Kevrekidis, Ioannis G; Benziger, Jay

    2012-02-01

    Liquid water is pushed through flow channels of fuel cells, where one surface is a porous carbon electrode made up of carbon fibers. Water drops grow on the fibrous carbon surface in the gas flow channel. The drops adhere to the superficial fiber surfaces but exhibit little penetration into the voids between the fibers. The fibrous surfaces are hydrophobic, but there is a substantial threshold force necessary to initiate water drop motion. Once the water drops begin to move, however, the adhesive force decreases and drops move with minimal friction, similar to motion on superhydrophobic materials. We report here studies of water wetting and water drop motion on typical porous carbon materials (carbon paper and carbon cloth) employed in fuel cells. The static coefficient of friction on these textured surfaces is comparable to that for smooth Teflon. But the dynamic coefficient of friction is several orders of magnitude smaller on the textured surfaces than on smooth Teflon. Carbon cloth displays a much smaller static contact angle hysteresis than carbon paper due to its two-scale roughness. The dynamic contact angle hysteresis for carbon paper is greatly reduced compared to the static contact angle hysteresis. Enhanced dynamic hydrophobicity is suggested to result from the extent to which a dynamic contact line can track topological heterogeneities of the liquid/solid interface.

  15. 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).

  16. ISOLASI DAN KARAKTERISASI CaO (KALSIUM OKSIDA) DARI CANGKANG KERANG DARAH (Anadara Granosa)

    OpenAIRE

    yahya, afdaliah

    2014-01-01

    Seashells from species Anadara Granosa were used as raw materials to isolate CaO by calcination at temperatures of 1000 ?? C for 5 hours to obtain the CaO content is 99.61%. This process can take place due to the conversion of CaCO3 into CaO

  17. Perancangan, Pembuatan dan Karakterisasi Tranduser Ultrasonik 3,5 MHz Untuk Pengujian Bahan Padat

    Directory of Open Access Journals (Sweden)

    Mokhamad Halim Fathoni

    2013-09-01

    Full Text Available Dalam tugas akhir ini telah dibuat sepasang transduser ultrasonik untuk pengujian bahan padat. Konstruksi transduser ultrasonik yang dibuat terdiri dari holder berbahan akrilik dan kuningan, backing material berbahan styrofoam, epoxy dan busa karet, elemen aktif berbahan piezoelektrik dan matching layers menggunakan akrilik. Bahan penyusun konstruksi tersebut dilakukan pengujian untuk mengetahui  karakteristik transduser ultrasonik.Dari hasil pengujian yang telah dilakukan diperoleh  karakteristik transduser ultrasonik dengan holder berbahan akrilik, backing material berbahan styrofoam, frekuensi resonansi sebesar 3.5 MHz, bandwith sebesar 2.04 MHz, respon impulse >10 siklus, delay sebesar 1,6 us ,Q (faktor kualitas mekanis getaran harmonis sebesar 1,667 dan impedansi sebesar 78,6 ohm. Untuk pengujian cacat bahan didapatkan hasil bahwa transduser ultrasonik bisa mendeteksi adanya cacat dan mengestimasi panjang ukuran cacat dengan error pengukuran sebesar 0.5 cm. Namun, kedalaman cacat tidak bisa ditentukan sehingga dibutuhkan pengukuran sistem echo untuk memperbaiki pengukuran tersebut.

  18. Pembuatan Dan Karakterisasi Adsorben Cangkang Telur Bebek Yang Diaktivasi Secara Termal

    OpenAIRE

    Jasinda

    2014-01-01

    Duck eggshell’s adsorbent can be used to adsorp heavy metal. Adsorption ability of the adsorbent can be increased with thermally activation process. The purpose of this research is to study the physical properties and characteristic of duck eggshell’s adsorbent which be activated by thermal, the effect of activation temperature towards the percentage of sample weight loss, adsorbent’s density and surface area, and the adsorbent ability to adsorp heavy metal Cd(II). Materials that used in this...

  19. Sintesis dan Karakterisasi Grafena dengan Metode Reduksi Grafit Oksida Menggunakan Pereduksi Zn

    Directory of Open Access Journals (Sweden)

    Yudha Taufantri

    2016-05-01

    Full Text Available Graphene is a thin material, has a hexagonal two-dimentional lattice and is considered as an interesting material for adsorption process. Nowadays, graphene has been known as a potential material for diverse application, such as adsorbent. In this study graphene was synthesized from graphite. Furthermore, graphene was applied for adsorption of dichloro diphenyl trichloroethane (DDT. Graphene was synthesized by Hummer’s method using hydrothermal and reduced by Zn. The samples were characterized by Scanning Electron Microscope (SEM and X-Ray Diffraction (XRD methods. The results of the XRD showed graphene structure in the 2θ, appeared at 23.9369 with interlayer spacing was about 3.71763 Å, compared with graphite oxide structure in the 2θ appeared at 11.2055 with interlayer spacing was about 7.89649 Å. The results of SEM analysis showed graphene has one layer with planar hexagonal structure and seems transparent whose single layer and multi layers. The graphene adsorption was analyzed by using the UV-Visible spectrophotometer. The results indicated the surface area of graphene was shown as 46.8563 m2/g. The amount of DDT adsorbed by graphene during 15 minutes was 7.5859 mg/g. This adsorption mechanism of DDT and graphene might be due to π-π and hydrogen interactions.   Keywords: Adsorption, dichloro diphenyl trichloroethane (DDT, graphena. DOI: http://dx.doi.org/10.15408/jkv.v2i1.2233

  20. Hole-Transporting Materials for Printable Perovskite Solar Cells

    Science.gov (United States)

    Salunke, Jagadish K.; Priimagi, Arri

    2017-01-01

    Perovskite solar cells (PSCs) represent undoubtedly the most significant breakthrough in photovoltaic technology since the 1970s, with an increase in their power conversion efficiency from less than 5% to over 22% in just a few years. Hole-transporting materials (HTMs) are an essential building block of PSC architectures. Currently, 2,2’,7,7’-tetrakis-(N,N’-di-p-methoxyphenylamine)-9,9’-spirobifluorene), better known as spiro-OMeTAD, is the most widely-used HTM to obtain high-efficiency devices. However, it is a tremendously expensive material with mediocre hole carrier mobility. To ensure wide-scale application of PSC-based technologies, alternative HTMs are being proposed. Solution-processable HTMs are crucial to develop inexpensive, high-throughput and printable large-area PSCs. In this review, we present the most recent advances in the design and development of different types of HTMs, with a particular focus on mesoscopic PSCs. Finally, we outline possible future research directions for further optimization of the HTMs to achieve low-cost, stable and large-area PSCs. PMID:28914823

  1. Hole-Transporting Materials for Printable Perovskite Solar Cells

    Directory of Open Access Journals (Sweden)

    Paola Vivo

    2017-09-01

    Full Text Available Perovskite solar cells (PSCs represent undoubtedly the most significant breakthrough in photovoltaic technology since the 1970s, with an increase in their power conversion efficiency from less than 5% to over 22% in just a few years. Hole-transporting materials (HTMs are an essential building block of PSC architectures. Currently, 2,2’,7,7’-tetrakis-(N,N’-di-p-methoxyphenylamine-9,9’-spirobifluorene, better known as spiro-OMeTAD, is the most widely-used HTM to obtain high-efficiency devices. However, it is a tremendously expensive material with mediocre hole carrier mobility. To ensure wide-scale application of PSC-based technologies, alternative HTMs are being proposed. Solution-processable HTMs are crucial to develop inexpensive, high-throughput and printable large-area PSCs. In this review, we present the most recent advances in the design and development of different types of HTMs, with a particular focus on mesoscopic PSCs. Finally, we outline possible future research directions for further optimization of the HTMs to achieve low-cost, stable and large-area PSCs.

  2. Installing Mechanics of Granular Materials (MGM) experiment Test Cell

    Science.gov (United States)

    1996-01-01

    Astronaut Jay Apt installs Mechanics of Granular Materials (MGM0 test cell on STS-79. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. MGM experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. (Credit: NASA/John Space Center).

  3. Nuclear Materials Characterization in the Materials and Fuels Complex Analytical Hot Cells

    International Nuclear Information System (INIS)

    Rodriquez, Michael

    2009-01-01

    As energy prices skyrocket and interest in alternative, clean energy sources builds, interest in nuclear energy has increased. This increased interest in nuclear energy has been termed the 'Nuclear Renaissance'. The performance of nuclear fuels, fuels and reactor materials and waste products are becoming a more important issue as the potential for designing new nuclear reactors is more immediate. The Idaho National Laboratory (INL) Materials and Fuels Complex (MFC) Analytical Laboratory Hot Cells (ALHC) are rising to the challenge of characterizing new reactor materials, byproducts and performance. The ALHC is a facility located near Idaho Falls, Idaho at the INL Site. It was built in 1958 as part of the former Argonne National Laboratory West Complex to support the operation of the second Experimental Breeder Reactor (EBR-II). It is part of a larger analytical laboratory structure that includes wet chemistry, instrumentation and radiochemistry laboratories. The purpose of the ALHC is to perform analytical chemistry work on highly radioactive materials. The primary work in the ALHC has traditionally been dissolution of nuclear materials so that less radioactive subsamples (aliquots) could be transferred to other sections of the laboratory for analysis. Over the last 50 years though, the capabilities within the ALHC have also become independent of other laboratory sections in a number of ways. While dissolution, digestion and subdividing samples are still a vitally important role, the ALHC has stand alone capabilities in the area of immersion density, gamma scanning and combustion gas analysis. Recent use of the ALHC for immersion density shows that extremely fine and delicate operations can be performed with the master-slave manipulators by qualified operators. Twenty milligram samples were tested for immersion density to determine the expansion of uranium dioxide after irradiation in a nuclear reactor. The data collected confirmed modeling analysis with very tight

  4. Karakterisasi Mutu dan Nilai Gizi Nasi Mocaf dari Beras Analog - (Characterization of Quality and Nutrition Value of Cooked Rice Mocaf from Rice Analog

    Directory of Open Access Journals (Sweden)

    Enny Hawani Loebis

    2017-06-01

    Full Text Available Dependence on rice consumption needs to be reduced to overcome the problems of rice supply and health problems. Alternative proposed is producing mocaf-based rice analog. This research aims to study the quality characterization and nutritional value of mocaf-based rice analog. Rice mocaf was made based on mixture of mocaf, rice flour, water and palm oil using variable: 50, 60 and 70% mocaf.  Mocaf rice then cooked by using rice cooker, steamer or microwave. The results showed mocaf rice 60% yield highest calorific value.  The best cooking method  was steaming that resulted nutrient content and calorific value consisting of 49.15% water; 2.05% fat; 2.09% protein; 46.45% carbohydrate; 35.8 mg/kg of iron; 403.4 mg/kg of potassium; 193.8 mg/kg of calcium, 2.0 mg/kg of vitamin B1 and 212.53 ca/100 g calorific value.Keywords: mocaf, nutritional value, quality characterisation, rice ABSTRAKKetergantungan pada konsumsi beras perlu dikurangi untuk mengatasi permasalahan pasokan beras dan masalah kesehatan. Alternatif yang dapat diusulkan adalah dengan pembuatan beras analog berbasis mocaf. Penelitian ini bertujuan mempelajari karakterisasi mutu dan nilai gizi nasi mocaf dari beras analog. Beras mocaf dibuat berdasarkan campuran mocaf, tepung beras, air dan minyak goreng sawit, dengan komposisi mocaf  50, 60 dan 70%. Beras mocaf kemudian dimasak dengan cara menggunakan rice cooker, pengukusan atau microwave. Hasil penelitian menunjukkan beras mocaf 60% menghasilkan nasi mocaf dengan nilai kalori tertinggi. Pemasakan terbaik adalah dengan cara pengukusan dengan kandungan gizi dan nilai kalori yang dihasilkan terdiri dari 49,15%  air; 2,05% lemak; 2,09% protein; 46,45% karbohidrat; 35,8 mg/kg besi; 403,4 mg/kg kalium; 193,8 mg/kg kalsium, 2,0 mg/kg vitamin B1 dan 212,53 kal/100 g nilai kalori.Kata kunci: beras, karakterisasi mutu, mocaf, nilai gizi

  5. Karakterisasi Faktor-faktor Virulensi Staphylococcus aureus Asal Susu Kambing Peranakan Ettawa secara Fenotip dan Genotip

    Directory of Open Access Journals (Sweden)

    Khusnan Khusnan

    2017-02-01

    85,7% hydrophil. Staphylococcus aureus (85,7% isolates abled to aglutinated sheep blood cells. Based on genotypic analysis of Staphylococcus aureus could be detected coa gene (92,8%, clf gene (64,3%, fnbA gene (78,6%, and fnbB gene (64,3%. Based on the phenotypic and genotypic characters, it can be concluded that Staphylococcus aureus are virulent strains. This information can be used as the basis for control mastitis in PE goats

  6. Karakterisasi Karbon Aktif Asal Tumbuhan dan Tulang Hewan Menggunakan FTIR dan Analisis Kemometrika

    Directory of Open Access Journals (Sweden)

    Yusraini Dian Inayati Siregar

    2016-08-01

    Full Text Available Activated carbon is widely used as an adsorbent in gas purification, refining pulp, and also for the purification of food products, among others, oil purification, refining cane sugar, beet sugar, corn sugar, eliminate the taste and odor of drinking water. Carbon active can be derived from plant and animal bone. This study aims to analyze the differences in spectral profile of activated carbon from plants and animal bones by using FTIR. The data combined with the results of FTIR analysis chemometrics to classify and categorize the data, so it is clear where the activated carbon from plants and animal bones. FTIR analysis methods combined with chemometrics analysis through modeling PCA (Principal Component Analysis and PLS-DA (Partial Least Squares-Discriminant Analysis is able to distinguish between activated carbon derived from plants (coconut shell and animal bones (beef and pork. PCA with total diversity of 89% were able to classify the samples of activated carbon plant and animal bones. PLSDA models successfully predicted the test sample is based on a sample group of activated carbon raw material. Manufacture of activated carbon predictive models with PLS calibration generates R2, R2 predictions, RMSEC, and RMSEP respectively by 0.9787389, 0.9662152, 0.0687364 and 0.0928362. The results showed that FTIR spectra and can be used to distinguish chemometrics activated carbon derived from plant and animal bonesDOI :http://dx.doi.org/10.15408/jkv.v0i0.3146.

  7. Identifikasi dan Karakterisasi Senyawa Bioaktif Antikanker dari Ekstrak Etanol Kulit Batang Kayu Bitti (Vitex cofassus

    Directory of Open Access Journals (Sweden)

    Nuraini Nuraini

    2015-07-01

    Full Text Available Bitti wood (Vitex cofassus is one of the plants in Verbenaceae family and known by the people of South Sulawesi as the building material. The aims of this research  is to identify and characterize  the anticancer bioactive compound in ethanol extract of vortex Bitti wood (Vitex cofassus and to determine the bioactivity value. This research uses extraction and fraction method, identification uses thin layer chromatography (TLC and phytochemical test to know metabolism secunder and characterization with FTIR. The result from isolation shows that the amorf shape with 18 mg has white and yellow colour. The purification is conduted by using spectroscopy test FTIR. The result shows that the crystal has flavonoids compound which is solid with phytochemical test like positive product by using FeCl3 5%, NaOH 10% and H2SO4 P. Thick extract, fraction combination and amorf continued with toxicity test with the animal test Artemia salina Leach it uses Brine Shrimp Lethality test (BST method. LC50 value which is gotten the three samples is thick extract 29,51 ppm, combination fraction 169,82 ppm and amorf 562,34 ppm.

  8. Potential electrode materials for symmetrical Solid Oxide Fuel Cells

    Directory of Open Access Journals (Sweden)

    Ruiz Morales, J. C.

    2008-08-01

    Full Text Available Chromites, titanates and Pt-YSZ-CeO2 cermets have been investigated as potential electrode materials for an alternative concept of Solid Oxide Fuel Cell (SOFC, the symmetrical SOFCs (SFC. In this configuration, the same electrode material is used simultaneously as anode and cathode. Interconnector materials, such as chromites, could be considered as potential SFC electrodes, at least under pure hydrogen-fed at relatively high temperatures, as they do not exhibit significant catalytic activity towards hydrocarbon oxidation. This may be overcome by partially substituting Cr in the perovskite B-sites by other transition metal cations such as Mn. La0.75Sr0.25Cr0.5Mn0.5O3-δ (LSCM is a good candidate for such SFCs, rendering fuel cell performances in excess of 500 and 300mW/cm2 using pure H2 and CH4 as fuel, at 950 oC. Similarly, typical n-type electronic conductors traditionally regarded as anode materials, such as strontium titanates, may also operate under oxidising conditions as cathodes by substituting some Ti content for Fe to introduce p-type conductivity. Preliminary electrochemical experiments on La4Sr8Ti12-xFexO38-δ-based SFCs show that they perform reasonably well under humidified H2, at high temperatures. A third group of materials is the support material of any typical cermet anode, i.e. YSZ, CeO2 plus a current collector. It has been found that this combination could be optimised to operate as SFC electrodes, rendering performances of 400mW/cm2 under humidified pure H2 at 950oC.

    Cromitas, titanatos y cermets de Pt-YSZ-CeO2 han sido investigados como potenciales materiales de electrodo para un concepto alternativo de Pilas de Combustible de Óxidos Sólidos (SOFC, las pilas SOFC simétricas (SFC. En

  9. STUDI KARAKTERISASI LAJU KOROSI LOGAM ALUMINIUM DAN PELAPISAN DENGAN MENGGUNAKAN MEMBRAN SELLULOSA ASETAT

    Directory of Open Access Journals (Sweden)

    Andarany Kartika Sari

    2017-02-01

    Full Text Available Korosi terjadi akibat adanya reaksi oksidasi dan reduksi antara material dengan lingkungannya. Reaksi oksidasi diartikan sebagai reaksi yang menghasilkan elektron dan reduksi adalah antara dua unsur yang mengikat elektron . Korosi merupakan peristiwa yang tidak mungkin dielakan dalam kehidupan baik dalam lingkungan industri maupun rumah tangga. Korosi tidak dapat dihilangkan, namun dapat dikendalikan lajunya. Secara teoritis, menurut tabel deret volta, Aluminium merupakan logam yang mudah terkorosi. Pada penelitian ini dilakukan upaya untuk mengkarakterisasikan jenis korosinya dengan menggunakan media asam lemah (asetat, asam kuat (HCl, dan basa kuat (KOH. Pada percobaan dengan menggunakan media asam lemah (asetat, korosi yang terjadi adalah korosi sumuran (pitting corrosion. Pada percobaan menggunakan media asam kuat (HCl, pada konsentrasi rendah yang terjadi adalah korosi sumuran, sedangkan pada konsentrasi tinggi yang terjadi adalah korosi erosi. Salah satu metode pencegahan terjadinya korosi yaitu dengan menggunakan metode pelapisan (coating. Pada penelitian ini, upaya yang dilakukan untuk memperlambat laju korosinya adalah dengan cara melapisi logam dengan “Sellulosa Asetat”(CA. Sellulosa asetat terdiri dari powder sellulosa dilarutkan dengan asam asetat 99%, kemudian diaplikasikan pada logam aluminium. Hasil percobaan perendaman dengan media asam asetat, yang terjadi adalah bahwa sellulosa asetat membuat laju korosi semakin meningkat sebesar 54% dibanding sebelum dilapisi. Pada percobaan perendaman dengan menggunakan asam HCl, sellulosa asetat mampu memperlambat laju korosi sebesar 47.479%. Dan pada percobaan perendaman dengan larutan KOH, efisiensi inhibisinya mencapai 255% lajunya lebih cepat dibandingkan sebelum dilapisi. Hal ini terjadi dikarenakan adanya proses deasetilasi dimana proses ini adalah proses terputusnya gugus asetil pada membran sellulosa asetat sehingga kemampuan menempel pada permukaan logam menjadi menurun.

  10. KARAKTERISASI ENAM VARIETAS BUNCIS (Phaseolus vulgaris L. BERDASARKAN PANDUAN PENGUJIAN INDIVIDUAL

    Directory of Open Access Journals (Sweden)

    Vina Eka Aristya

    2016-02-01

    Full Text Available Beans (Phaseolus vulgaris L. is a plant that has the potential for mainstream consumers, have a large enough market opportunity and a source of vegetable protein. “Perancis” varieties are local Central Java bean varieties are widely grown in the Bandungan area. “Perancis” varieties not currently provide enough characters clear and complete. Test objectives were (1 to characterize the “Perancis” varieties in order to have a complete character information varieties and (2 to determine distinctness, uniformity and stability of the “Perancis” varieties compared with varieties Gypsie, Spectacular, Balitsa 1, Balitsa 2 and PV 072 using guidelines for the conduct of test for distinctness, uniformity and stability reference beans. Implemented on the Garden Seed Testing Bandungan Horticulture, Central Java with an altitude of 560-800 meters above sea level the place. Materials testing consists of six varieties of beans are “Perancis” varieties and the varieties used for comparison Gypsie, Spectacular, Balitsa 1, Balitsa 2 and PV 072. This research used a randomized block design six varieties of beans are planted side by side on three experimental plots as replications. Parameters observed include 49 characters corresponding guidelines bean plants are divided into the plant character, leaves character, flower character, pods character and seed character. Test results based guidelines, “Perancis” varieties showed eight unique characters compared to varieties of Gypsie, Spectacular, Balitsa 1, Balitsa 2 and PV 072 ie. plant height, leaf color, leaf rugosity, long (including beak pods, the degree of the pods curvature, the shape of distal part (excluding beak pods, length of beak pods and curvature of beak pods and “Perancis” varieties have uniformity and stability.

  11. Carbon superfine materials as a promising material for Gluconobacter oxydans based microbial fuel cells

    Science.gov (United States)

    Tenchurin, Timur K.; Reshetilov, Anatoly N.; Plekhanova, Yuliya V.; Tarasov, Sergey E.; Bykov, Aleksandr G.; Gutorov, Michail A.; Alferov, Sergey V.; Chvalun, Sergei N.; Orekhov, Anton S.; Shepelev, Alexey D.; Gotovtsev, Pavel M.; Vasilov, Raif G.

    2018-02-01

    We have investigated the properties of a several bioelectrodes based on the immobilization of Gluconobacter oxydans bacterial cells on carbon superfine materials (CFMs). We use three types of CFMs (as adopted by the working classification CFM 1-3). All bioelectrodes was formed by covering the surface of the CFM via suspension of bacteria in a chitosan gel. The properties of samples are evaluated by measuring the physiological state of the bacteria immobilized: (a) recording the intensity of cellular respiration, (b) for measuring the charge transport characteristics of electrode (bioelectrocatalysis), and (c) by measuring the electrode impedance. Measurements (b) and (c) are made on two and three-electrode circuits in the oxidation of ethanol in the presence of 2,6-dichlorophenol electron transport mediator. For CFMs 1 and 2 the electron transport by the oxidation of the substrate is not registered, while for CFM 3 the current generation occurs. The resistance of CFM 3 bioelectrode is below the resistance of CFMs 1 and 2 both before (39.6 kΩ/cm2 for CFM 3, 630 Ω/cm2 for CFM 2, and 1329 Ω/cm2 for CFM 1) and after the addition of the substrate (2.9 kΩ/cm2 for CFM 3, 45 kΩ/cm2 for CFM 2, and 58 kΩ/cm2 for CFM 1). The bioelectrode made of CFM 3 has a capacitance of 196 μF/cm2—greater than two orders of magnitude of the bioelectrode capacity of CFMs 1 and 2 (0.51 and 0.58 μF/cm2, respectively). It is important to further study the properties of the CFM class of materials, which are promising as the basis of mechanically flexible electrodes with controlled parameters.

  12. BAKTERI PROBIOTIK DALAM BUDIDAYA UDANG: SELEKSI, MEKANISME AKSI, KARAKTERISASI, DAN APLIKASINYA SEBAGAI AGEN BIOKONTROL

    Directory of Open Access Journals (Sweden)

    Widanarni

    2008-08-01

    Full Text Available Bacterial disease attack occurs at the hatchery stage, which is considered to be the most serious threat, and often results in mass mortality of shrimp larvae by vibrosis which is that caused by a luminous bacterium identified as Vibrio harveyi. This research was carried out to obtain local isolates of probiotic bacteria that were able to inhibit the growth of V. harveyi and effectively apply it as a biocontrol of vibriosis in shrimp cultures. The research was carried out as follows: (1 In vitro and in vivo selection of probiotic bacteria candidates, (2 Study of the action mechanism and characterization of the selected pro biotic bacteria, (3 Study on application of the selected probiotic bacteria as a biocontrol agent in shrimp cultures. Results of in vitro and in vivo selection provided the best three isolates, which were 1Ub, SKT-b and Ua. The survival rate of shrimp larvae which were not only inoculated by V. harveyi but also with 1Ub, SKT-b and Ua probiotic bacteria were 88.33, 83.33, and 81.67% respectively; where as the positive control treatment (merely inoculated with V. harveyi gave a 41.67% survival rate and the negative control (without bacterial addition was 68.33%. Studies using a rifampicin resistant marker (RfR demonstrated that the number of V. harveyi MR5339 RfR cells in treatments without probiotic addition were higher than the treatment with the probiotic bacteria, in dead larvae, living larvae, as well as in the culture media. Partial sequencing of the I6S-rRNA gene showed that the I Ub isolate was similar to Pseudoalteromonas piscicida, whereas the SKT -b and Ua isolates were similar to Vibrio alginolyticus. Selected probiotic bacteria could be applied directly to shrimp larva culture media, or orally through enrichment of both natural and artificial food

  13. Nanostructured Semiconductor Materials for Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Carmen Cavallo

    2017-01-01

    Full Text Available Since O’Regan and Grätzel’s first report in 1991, dye-sensitized solar cells (DSSCs appeared immediately as a promising low-cost photovoltaic technology. In fact, though being far less efficient than conventional silicon-based photovoltaics (being the maximum, lab scale prototype reported efficiency around 13%, the simple design of the device and the absence of the strict and expensive manufacturing processes needed for conventional photovoltaics make them attractive in small-power applications especially in low-light conditions, where they outperform their silicon counterparts. Nanomaterials are at the very heart of DSSC, as the success of its design is due to the use of nanostructures at both the anode and the cathode. In this review, we present the state of the art for both n-type and p-type semiconductors used in the photoelectrodes of DSSCs, showing the evolution of the materials during the 25 years of history of this kind of devices. In the case of p-type semiconductors, also some other energy conversion applications are touched upon.

  14. 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

  15. Pembuatan dan Karakterisasi Tinta Serbuk Printer Berbahan Baku Arang Aktif dari Limbah Padat Pengolahan Gambir

    Directory of Open Access Journals (Sweden)

    Yudo Purnomo

    2017-12-01

    Full Text Available Research on the utilization of tannins and catechins of gambier has been done a lot. There is no research report however that examines the utilization of gambier processing solid waste. The objective of the research was to utilize the solid waste of gambier processing as a raw material of printer toner. The research was done through pyrolysis process of solid waste with temperature variation 400, 500, 600oC and time variation 30, 60 minutes. The highest carbon content was obtained 42% with 400oC temperature and 60 minutes. The pyrolysis process of the gambier solid waste was further carried out at the optimum temperature and time. The charcoal was activated with H3PO4 at concentrations 0; 5; and 10% for 24 hours, cooled and washed to remove residual of H3PO4, then drying in the oven at temperature 115oC for 24 hours. Size reduction process used a ball milling for 2 hours with speed 500 rpm. Fixed carbon content was obtained between 43-51%. The results of morphological testing by scanning electron microscope showed that the produced carbon powder had not a uniform size yet. The average particle size was between 5-10 µm with polydispersity index 0.9. The most mineral elements of carbon powder analysis using XRF were Ca, Mg, K, Si, Fe, and P. Testing of print quality based on ISO/IEC 19752:2004 using laser jet printers had not provided optimal results yet.ABSTRAKPenelitian pemanfaatan tanin dan katekin gambir telah banyak dilakukan. Namun, belum dilaporkan penelitian yang mengkaji pemanfaatan limbah padat pengolahan gambir. Tujuan penelitian adalah memanfaatkan limbah padat pengolahan gambir sebagai bahan baku pembuatan tinta serbuk printer. Penelitian dilakukan melalui proses pirolisis limbah padat dengan variasi suhu 400, 500, 600oC dan variasi waktu 30, 60 menit. Kadar karbon terikat tertinggi diperoleh sebesar 42% dengan suhu pirolisis 400oC selama 60 menit. Proses pirolisis limbah padat gambir selanjutnya dilakukan pada suhu dan waktu optimal

  16. 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

  17. 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

  18. Injectable scaffold materials differ in their cell instructive effects on primary human myoblasts

    DEFF Research Database (Denmark)

    Hejbøl, Eva Kildall; Sellathurai, Jeeva; Nair, Prabha Damodaran

    2017-01-01

    Scaffolds are materials used for delivery of cells for regeneration of tissues. They support three-dimensional organization and improve cell survival. For the repair of small skeletal muscles, injections of small volumes of cells are attractive, and injectable scaffolds for delivery of cells offer...

  19. Device and materials modeling in PEM fuel cells

    National Research Council Canada - National Science Library

    Paddison, Stephen J; Promislow, Keith

    2009-01-01

    .... Materials modeling include subjects relating to the membrane and the catalyst such as proton conduction, atomistic structural modeling, quantum molecular dynamics, and molecular-level modeling...

  20. Oral epithelial cell reaction after exposure to Invisalign plastic material.

    Science.gov (United States)

    Premaraj, Thyagaseely; Simet, Samantha; Beatty, Mark; Premaraj, Sundaralingam

    2014-01-01

    Invisalign plastic aligners (Align Technology, Santa Clara, Calif) are used to correct malocclusions. The aligners wrap around the teeth and are in contact with gingival epithelium during treatment. The purpose of this study was to evaluate the cellular responses of oral epithelium exposed to Invisalign plastic in vitro. Oral epithelial cells were exposed to eluate obtained by soaking Invisalign plastic in either saline solution or artificial saliva for 2, 4, and 8 weeks. Cells grown in media containing saline solution or saliva served as controls. Morphologic changes were assessed by light microscopy. The 3-[4, 5-dimethythiazol- 2-yl]-2, 5-diphenyl tetrazolium bromide assay and flow cytometry were used to determine cell viability and membrane integrity, respectively. Cellular adhesion and micromotion of epithelial cells were measured in real time by electrical cell-substrate impedance sensing. Cells exposed to saline-solution eluate appeared rounded, were lifted from the culture plates, and demonstrated significantly increased metabolic inactivity or cell death (P <0.05). Saliva eluates did not induce significant changes in cell viability compared with untreated cells. Flow cytometry and electric cell-substrate impedance sensing showed that cells treated with saline-solution eluate exhibited compromised membrane integrity, and reduced cell-to-cell contact and mobility when compared with saliva-eluate treatment. Exposure to Invisalign plastic caused changes in viability, membrane permeability, and adhesion of epithelial cells in a saline-solution environment. Microleakage and hapten formation secondary to compromised epithelial integrity might lead to isocyanate allergy, which could be systemic or localized to gingiva. However, these results suggest that saliva might offer protection. Copyright © 2014 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

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

    NARCIS (Netherlands)

    Deelen, J. van; Tezsevin, Y.; Barink, M.

    2016-01-01

    The trade-off between transmittance and conductivity of the front contact material poses abottleneck 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

  2. Evaluation of Commercial-off-the-Shelf Materials for the Preservation of Gram Positive Vegetative Cells

    Science.gov (United States)

    2017-02-01

    EVALUATION OF COMMERCIAL-OFF-THE-SHELF MATERIALS FOR THE PRESERVATION OF GRAM-POSITIVE VEGETATIVE CELLS ECBC-TR-1435 Daniel Angelini...Commercial-off-the-Shelf Materials for the Preservation of Gram-Positive Vegetative Cells 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM...through direct culture of the agents themselves. Materials have been developed to preserve the viability of pathogens contained within clinical

  3. BIOLOGICAL ACTIVITY OF FIBRONECTIN AT THE CELL-MATERIAL INTERFACE

    OpenAIRE

    González García, Cristina

    2012-01-01

    Esta tesis aborda la actividad biológica de la fibronectina (FN) como proteína de interfase en la interacción célula-material. La tesis investiga la respuesta de la proteína, en términos de cantidad adsorbida y conformación, ante diferentes propiedades físico-químicas del material. Además, se correlaciona la respuesta celular temprana y la funcionalidad celular con el estado de la proteína adsorbida sobre el material. Para ello se prepararon diferentes series de materiales con propiedades...

  4. Connexin membrane materials as potent inhibitors of breast cancer cell migration.

    Science.gov (United States)

    Ferrati, Silvia; Gadok, Avinash K; Brunaugh, Ashlee D; Zhao, Chi; Heersema, Lara A; Smyth, Hugh D C; Stachowiak, Jeanne C

    2017-08-01

    Gap junction (GJ) channels facilitate cell-cell communication through the exchange of chemical and mechanical signals, ensuring proper tissue development and homeostasis. The complex, disease stage-dependent role of connexins in breast cancer progression has been extensively studied over the past two decades. In the early stages of breast cancer, substantial evidence supports the role of GJ channels, formed by connexins at the interfaces between neighbouring cells, as suppressors of cell migration and proliferation. These findings suggest that materials that reintroduce connexins into the tumour cell environment have the potential to inhibit cell migration. Here, we report that exposure of highly metastatic MDA-MB-231 breast tumour cells to connexin-rich biovesicle materials potently suppresses cell migration. Specifically, these biovesicles, which can form GJ interfaces with cells, were extracted from the plasma membrane of donor cells engineered to express a high concentration of functional connexin 43 channels. These connexin-rich membrane materials dramatically reduced cell migration in both a transwell migration assay and a scratch closure assay. Collectively, these results suggest that using membrane materials to reintroduce connexins into the tumour cell environment provides a novel approach for combating cell migration and invasion. © 2017 The Author(s).

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

    CERN Document Server

    Corti, Horacio R; Antolini, Ermete

    2014-01-01

    After an introductory overview of this emerging form of clean, portable energy, experts from industry and academia discuss the challenges in materials development, performance, and commercialization standing between DAFCs and widespread public use.

  6. High-efficiency solar cells physics, materials, and devices

    CERN Document Server

    Wang, Xiaodong

    2013-01-01

    This book creates a platform for knowledge sharing and dissemination of research on making current photovoltaic technology cheaper, creating advanced technologies based on new architectural designs, and developing new materials to serve as light absorbers.

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

    International Nuclear Information System (INIS)

    Rhee, Chang Kyu; Lee, Min Ku; Park, Junju; Lee, Gyoungja; Lee, Byung Cheol; Shin, Junhwa; Nho, Youngchang; Kang, Philhyun; Sohn, Joon Yong; Rang, Uhm Young

    2012-06-01

    The development of the single cell of SOFC with low operation temperature at and below 650 .deg. C(above 400 mW/cm 2 ) 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/cm 2 /50 cm 2 at 5M methanol) Ο The preparation of samples for MEA stack assembly

  8. 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

  9. 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

  10. Nano- and microstructured materials for in vitro studies of the physiology of vascular cells

    Directory of Open Access Journals (Sweden)

    Alexandra M. Greiner

    2016-11-01

    Full Text Available The extracellular environment of vascular cells in vivo is complex in its chemical composition, physical properties, and architecture. Consequently, it has been a great challenge to study vascular cell responses in vitro, either to understand their interaction with their native environment or to investigate their interaction with artificial structures such as implant surfaces. New procedures and techniques from materials science to fabricate bio-scaffolds and surfaces have enabled novel studies of vascular cell responses under well-defined, controllable culture conditions. These advancements are paving the way for a deeper understanding of vascular cell biology and materials–cell interaction. Here, we review previous work focusing on the interaction of vascular smooth muscle cells (SMCs and endothelial cells (ECs with materials having micro- and nanostructured surfaces. We summarize fabrication techniques for surface topographies, materials, geometries, biochemical functionalization, and mechanical properties of such materials. Furthermore, various studies on vascular cell behavior and their biological responses to micro- and nanostructured surfaces are reviewed. Emphasis is given to studies of cell morphology and motility, cell proliferation, the cytoskeleton and cell-matrix adhesions, and signal transduction pathways of vascular cells. We finalize with a short outlook on potential interesting future studies.

  11. 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

  12. Analytical techniques for characterization of raw materials in cell culture media

    OpenAIRE

    Sharma, Chandana; Drew, Barry; Head, Kevin; Pusuluri, Rani; Caple, Matthew V

    2011-01-01

    Abstract Raw materials are a critical part of any cell culture medium; therefore, it is of utmost importance to understand and characterize them for high-quality product. The raw material characterization (RMC) program at SAFC focuses on individual screening of raw materials both analytically and biologically. The goal of the program is to develop the best-in-class knowledge base of the raw materials used in SAFC’s media formulations and their impact on performance of products.

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

    International Nuclear Information System (INIS)

    Han, Inho; Vagaska, Barbora; Seo, Hyok Jin; Kang, Jae Kyeong; Kwon, Byeong-Ju; Lee, Mi Hee; Park, Jong-Chul

    2012-01-01

    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.

  14. Materials

    CSIR Research Space (South Africa)

    Van Wyk, Llewellyn V

    2009-02-01

    Full Text Available community. The construction industry is a significantly consumer of materials, using 50 per cent of all products produced globally. Building materials is any material which is used for a construction purpose. Many of these materials are sources from natural...

  15. Techniques for remote maintenance of in-cell material-handling system in the HFEF/N main cell

    International Nuclear Information System (INIS)

    Tobias, D.A.; Frickey, C.A.

    1975-01-01

    Operations in the main cell of HFEF/N have required development of remote handling equipment and unique techniques for maintaining the in-cell material-handling system. Specially designed equipment is used to remove a disabled crane or electromechanical manipulator bridge from its support rails and place it on floor stands for repair or maintenance. Support areas for the main cell, such as the spray chamber and hot repair area, provide essential decontamination, repair, and staging areas for the in-cell material-handling-system equipment and tools. A combined engineering and technical effort in upgrading existing master-slave manipulators has definitely reduced the requirements for their maintenance. The cell is primarily for postirradiation examination of LMFBR materials and fuel elements

  16. 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...

  17. Fuel-cell applied research: Electrocatalysis and materials

    Science.gov (United States)

    Srinivasan, S.; Isaacs, H. S.; McBreen, J.; Ogrady, W. E.; Olender, H.; Olmer, L. J.; Schouler, E. J. L.; Kordesch, K. V.

    1980-09-01

    Phosphoric acid electrolyte fuel cells and high temperature solid electrolyte fuel cells are discussed. The corrosion behavior of five furnace black carbon supports for platinum electrocatalysts in phosphoric acid was evaluated using a cyclic voltammetric technique. The electrode kinetic studies of the hydrogen oxidation and the oxygen reduction reactions on smooth platinum in phosphoric acid revealed that the entire decrease in performance of a fuel cell in this impure electrolyte is entirely due to the impurity. A mathematical model which describes the slow oxygen adsorption step is compared with the experimental polarization and impedance results of uncontaminated platinum electrodes in contact with yttria stabilized zirconia electrolytes. Attempts to explain discrepancies are made by assuming that the adsorption of oxygen followed a Langmuir and then a Frumkin adsorption isotherm. It is concluded that a site variation occurred on the electrode surface when potentials were varied in the cathodic region.

  18. Subtyping of nonsmall cell lung cancer on cytology specimens: Reproducibility of cytopathologic diagnoses on sparse material

    DEFF Research Database (Denmark)

    Haukali, O. S.; Henrik, H.; Olsen, Karen Ege

    2014-01-01

    Cytologic examination of fine-needle aspiration (material is increasingly used in diagnosing lung cancer. High interobserver agreement in distinguishing small-cell lung cancer from nonsmall-cell lung cancer (NSCLC) on cytologic material has been demonstrated. Because of new treatment......, cytoscrape (CS) can convert cytologic material into tissue fragments useful for IHC. The purpose of this study was to test the reproducibility of pulmonary malignant diagnoses, in particular distinction between subgroups of NSCLC, based on smeared material and IHC on CS. A consecutive series of May...

  19. 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.

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

    International Nuclear Information System (INIS)

    Wheeldon, Ian; Farhadi, Arash; Bick, Alexander G; Khademhosseini, Ali; Jabbari, Esmaiel

    2011-01-01

    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)

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

    Science.gov (United States)

    Wheeldon, Ian; Farhadi, Arash; Bick, Alexander G.; Jabbari, Esmaiel; Khademhosseini, Ali

    2011-01-01

    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 the interactions through nanoscale biomaterials engineering in order to study and direct cellular behaviors. Here, we review the nanoscale tissue engineering technologies for both two- and three-dimensional studies (2- and 3D), 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 scaffolds 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 the temporal changes in cellular microenvironment. PMID:21451238

  2. Doped SbTe phase change material in memory cells

    NARCIS (Netherlands)

    in ‘t Zandt, M.A.A.; Jedema, F.J.; Gravesteijn, Dirk J; Gravesteijn, D.J.; Attenborough, K.; Wolters, Robertus A.M.

    2009-01-01

    Phase Change Random Access Memory (PCRAM) is investigated as replacement for Flash. The memory concept is based on switching a chalcogenide from the crystalline (low ohmic) to the amorphous (high ohmic) state and vice versa. Basically two memory cell concepts exist: the Ovonic Unified Memory (OUM)

  3. Advanced materials and processes for polymer solar cell devices

    DEFF Research Database (Denmark)

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

    2010-01-01

    /fullerene mixtures and evaporated metal electrodes in a flat multilayer geometry. It is likely that significant advances can be found by pursuing many of these novel ideas further and the purpose of this review is to highlight these reports and hopefully spark new interest in materials and methods that may...... be performing less than the current state-of-the-art in their present form but that may have the potential to outperform these pending a larger investment in effort....

  4. Controlling Cell Functions and Fate with Surfaces and Hydrogels: The Role of Material Features in Cell Adhesion and Signal Transduction

    Directory of Open Access Journals (Sweden)

    Maurizio Ventre

    2016-03-01

    Full Text Available In their natural environment, cells are constantly exposed to a cohort of biochemical and biophysical signals that govern their functions and fate. Therefore, materials for biomedical applications, either in vivo or in vitro, should provide a replica of the complex patterns of biological signals. Thus, the development of a novel class of biomaterials requires, on the one side, the understanding of the dynamic interactions occurring at the interface of cells and materials; on the other, it requires the development of technologies able to integrate multiple signals precisely organized in time and space. A large body of studies aimed at investigating the mechanisms underpinning cell-material interactions is mostly based on 2D systems. While these have been instrumental in shaping our understanding of the recognition of and reaction to material stimuli, they lack the ability to capture central features of the natural cellular environment, such as dimensionality, remodelling and degradability. In this work, we review the fundamental traits of material signal sensing and cell response. We then present relevant technologies and materials that enable fabricating systems able to control various aspects of cell behavior, and we highlight potential differences that arise from 2D and 3D settings.

  5. Two-dimensional material-based bionano platforms to control mesenchymal stem cell differentiation.

    Science.gov (United States)

    Kang, Ee-Seul; Kim, Da-Seul; Suhito, Intan Rosalina; Lee, Wanhee; Song, Inbeom; Kim, Tae-Hyung

    2018-01-01

    In the past decade, stem cells, with their ability to differentiate into various types of cells, have been proven to be resourceful in regenerative medicine and tissue engineering. Despite the ability to repair damaged parts of organs and tissues, the use of stem cells still entails several limitations, such as low differentiation efficiency and difficulties in guiding differentiation. To address these limitations, nanotechnology approaches have been recently implemented in stem cell research. It has been discovered that stem cells, in combination with carbon-based functional materials, show enhanced regenerative performances in varying biophysical conditions. In particular, several studies have reported solutions to the conventional quandaries in biomedical engineering, using synergetic effects of nanohybrid materials, as well as further development of technologies to recover from diverse health conditions such as bone fracture and strokes. In this review, we discuss several prior studies regarding the application of various nanomaterials in controlling the behavior of stem cells. We focus on the potential of different types of nanomaterials, such as two-dimensional materials, gold nanoparticles, and three-dimensional nanohybrid composites, to control the differentiation of human mesenchymal stem cells (hMSCs). These materials have been found to affect stem cell functions via the adsorption of growth/differentiation factors on the surfaces of nanomaterials and the activation of signaling pathways that are mostly related to cell adhesion and differentiation (e.g., FAK, Smad, Erk, and Wnt). Controlling stem cell differentiation using biophysical factors, especially the use of nanohybrid materials to functionalize underlying substrates wherein the cells attach and grow, is a promising strategy to achieve cells of interest in a highly efficient manner. We hope that this review will facilitate the use of other types of newly discovered and/or synthesized nanomaterials

  6. 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.

  7. Microstructural evolution of nanograin nickel-zirconia cermet anode materials for solid oxide fuel cell applications

    International Nuclear Information System (INIS)

    Nayak, Bibhuti Bhusan

    2012-01-01

    The aim of the study is to study the structure, microstructure, porosity, thermal expansion, electrical conductivity and electrochemical behavior of the anode material thus synthesized in order to find its suitability for solid oxide fuel cell (SOFC) anode application

  8. 3D Printing of Lotus Root-Like Biomimetic Materials for Cell Delivery and Tissue Regeneration.

    Science.gov (United States)

    Feng, Chun; Zhang, Wenjie; Deng, Cuijun; Li, Guanglong; Chang, Jiang; Zhang, Zhiyuan; Jiang, Xinquan; Wu, Chengtie

    2017-12-01

    Biomimetic materials have drawn more and more attention in recent years. Regeneration of large bone defects is still a major clinical challenge. In addition, vascularization plays an important role in the process of large bone regeneration and microchannel structure can induce endothelial cells to form rudimentary vasculature. In recent years, 3D printing scaffolds are major materials for large bone defect repair. However, these traditional 3D scaffolds have low porosity and nonchannel structure, which impede angiogenesis and osteogenesis. In this study, inspired by the microstructure of natural plant lotus root, biomimetic materials with lotus root-like structures are successfully prepared via a modified 3D printing strategy. Compared with traditional 3D materials, these biomimetic materials can significantly improve in vitro cell attachment and proliferation as well as promote in vivo osteogenesis, indicating potential application for cell delivery and bone regeneration.

  9. Microfluidic synthesis of composite cross-gradient materials for investigating cell-biomaterial interactions.

    Science.gov (United States)

    He, Jiankang; Du, Yanan; Guo, Yuqi; Hancock, Matthew J; Wang, Ben; Shin, Hyeongho; Wu, Jinhui; Li, Dichen; Khademhosseini, Ali

    2011-01-01

    Combinatorial material synthesis is a powerful approach for creating composite material libraries for the high-throughput screening of cell-material interactions. Although current combinatorial screening platforms have been tremendously successful in identifying target (termed "hit") materials from composite material libraries, new material synthesis approaches are needed to further optimize the concentrations and blending ratios of the component materials. Here we employed a microfluidic platform to rapidly synthesize composite materials containing cross-gradients of gelatin and chitosan for investigating cell-biomaterial interactions. The microfluidic synthesis of the cross-gradient was optimized experimentally and theoretically to produce quantitatively controllable variations in the concentrations and blending ratios of the two components. The anisotropic chemical compositions of the gelatin/chitosan cross-gradients were characterized by Fourier transform infrared spectrometry and X-ray photoelectron spectrometry. The three-dimensional (3D) porous gelatin/chitosan cross-gradient materials were shown to regulate the cellular morphology and proliferation of smooth muscle cells (SMCs) in a gradient-dependent manner. We envision that our microfluidic cross-gradient platform may accelerate the material development processes involved in a wide range of biomedical applications. © 2010 Wiley Periodicals, Inc.

  10. Reduced material model for closed cell metal foam infiltrated with phase change material based on high resolution numerical studies

    International Nuclear Information System (INIS)

    Ohsenbrügge, Christoph; Marth, Wieland; Navarro y de Sosa, Iñaki; Drossel, Welf-Guntram; Voigt, Axel

    2016-01-01

    Highlights: • Closed cell metal foam sandwich structures were investigated. • High resolution numerical studies were conducted using CT scan data. • A reduced model for use in commercial FE software reduces needed degrees of freedom. • Thermal inertia is increased about 4 to 5 times in PCM filled structures. • The reduced material model was verified using experimental data. - Abstract: The thermal behaviour of closed cell metal foam infiltrated with paraffin wax as latent heat storage for application in high precision tool machines was examined. Aluminium foam sandwiches with metallically bound cover layers were prepared in a powder metallurgical process and cross-sectional images of the structures were generated with X-ray computed tomography. Based on the image data a three dimensional highly detailed model was derived and prepared for simulation with the adaptive FE-library AMDiS. The pores were assumed to be filled with paraffin wax. The thermal conductivity and the transient thermal behaviour in the phase-change region were investigated. Based on the results from the highly detailed simulations a reduced model for use in commercial FE-software (ANSYS) was derived. It incorporates the properties of the matrix and the phase change material into a homogenized material. A sandwich-structure with and without paraffin was investigated experimentally under constant thermal load. The results were used to verify the reduced material model in ANSYS.

  11. Materials and Device Engineering for Efficient and Stable Polymer Solar Cells

    OpenAIRE

    Hansson, Rickard

    2017-01-01

    Polymer solar cells form a promising technology for converting sunlight into electricity, and have reached record efficiencies over 10% and lifetimes of several years. The performance of polymer solar cells depends strongly on the distribution of electron donor and acceptor materials in the active layer. To achieve longer lifetimes, degradation processes in the materials have to be understood. In this thesis, a set of complementary spectroscopy and microscopy techniques, among which soft X-ra...

  12. Device for transferring radioactive materials into a hot cell

    International Nuclear Information System (INIS)

    Engelmann, H.J.; Koller, J.

    1976-01-01

    The invention should ease the process of enclosing containers which contain radio-active material. A sliding tensioning arrangement is proposed, which can be clamped, and there is a container insert between this tensioning arrangement and the lock bar. The threee above-mentioned parts can be coupled up or uncoupled. The tensioning arrangement is preferably made as a pair of pliers surrounding the container. It is advantageous if the shielding container does not have to remain connected by a flange during the locking process. (UWI) [de

  13. REMOTE MATERIAL HANDLING IN THE YUCCA MOUNTAIN WASTE PACKAGE CLOSURE CELL AND SUPPORT AREA GLOVEBOX

    International Nuclear Information System (INIS)

    K.M. Croft; S.M. Allen; M.W. Borland

    2005-01-01

    The Yucca Mountain Waste Package Closure System (WPCS) cells provide for shielding of highly radioactive materials contained in unsealed waste packages. The purpose of the cells is to provide safe environments for package handling and sealing operations. Once sealed, the packages are placed in the Yucca Mountain Repository. Closure of a typical waste package involves a number of remote operations. Those involved typically include the placement of matched lids onto the waste package. The lids are then individually sealed to the waste package by welding. Currently, the waste package includes three lids. One lid is placed before movement of the waste package to the closure cell; the final two are placed inside the closure cell, where they are welded to the waste package. These and other important operations require considerable remote material handling within the cell environment. This paper discusses the remote material handling equipment, designs, functions, operations, and maintenance, relative to waste package closure

  14. 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.

  15. 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 ...

  16. 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.)

  17. Extracellular matrix elasticity and topography: material-based cues that affect cell function via conserved mechanisms

    Science.gov (United States)

    Janson, Isaac A.; Putnam, Andrew J.

    2014-01-01

    Chemical, mechanical, and topographic extracellular matrix (ECM) cues have been extensively studied for their influence on cell behavior. These ECM cues alter cell adhesion, cell shape, and cell migration, and activate signal transduction pathways to influence gene expression, proliferation, and differentiation. ECM elasticity and topography, in particular, have emerged as material properties of intense focus based on strong evidence these physical cue can partially dictate stem cell differentiation. Cells generate forces to pull on their adhesive contacts, and these tractional forces appear to be a common element of cells’ responses to both elasticity and topography. This review focuses on recently published work that links ECM topography and mechanics and their influence on differentiation and other cell behaviors, We also highlight signaling pathways typically implicated in mechanotransduction that are (or may be) shared by cells subjected to topographic cues. Finally, we conclude with a brief discussion of the potential implications of these commonalities for cell based therapies and biomaterial design. PMID:24910444

  18. Novel Materials for High Efficiency Direct Methanol Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Carson, Stephen [Arkema Inc.; Mountz, David [Arkema Inc.; He, Wensheng [Arkema Inc.; Zhang, Tao [Arkema Inc.

    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.

  19. Whole-cell based hybrid materials for green energy production, environmental remediation and smart cell-therapy.

    Science.gov (United States)

    Léonard, Alexandre; Dandoy, Philippe; Danloy, Emeric; Leroux, Grégory; Meunier, Christophe F; Rooke, Joanna C; Su, Bao-Lian

    2011-02-01

    This critical review highlights the advances that have been made over recent years in the domain of whole-cell immobilisation and encapsulation for applications relating to the environment and human health, particularly focusing on examples of photosynthetic plant cells, bacteria and algae as well as animal cells. Evidence that encapsulated photosynthetic cells remain active in terms of CO(2) sequestration and biotransformation (solar driven conversion of CO(2) into biofuels, drugs, fine chemicals etc.), coupled with the most recent advances made in the field of cell therapy, reveals the need to develop novel devices based on the preservation of living cells within abiotic porous frameworks. This review shall corroborate this statement by selecting precise examples that unambiguously demonstrate the necessity and the benefits of such smart materials. As will be described, the handling and exploitation of photosynthetic cells are enhanced by entrapment or encapsulation since the cells are physically separated from the liquid medium, thereby facilitating the recovery of the metabolites produced. In the case of animal cells, their encapsulation within a matrix is essential in order to create a physical barrier that can protect the cells auto-immune defenders upon implantation into a living body. For these two research axes, the key parameters that have to be kept in mind when designing hybrid materials will be identified, concentrating on essential aspects such as biocompatibility, mechanical strength and controlled porosity (264 references).

  20. Crosstalk between focal adhesions and material mechanical properties governs cell mechanics and functions.

    Science.gov (United States)

    Fusco, Sabato; Panzetta, Valeria; Embrione, Valerio; Netti, Paolo A

    2015-09-01

    Mechanical properties of materials strongly influence cell fate and functions. Focal adhesions are involved in the extremely important processes of mechanosensing and mechanotransduction. To address the relationship between the mechanical properties of cell substrates, focal adhesion/cytoskeleton assembly and cell functions, we investigated the behavior of NIH/3T3 cells over a wide range of stiffness (3-1000kPa) using two of the most common synthetic polymers for cell cultures: polyacrylamide and polydimethylsiloxane. An overlapping stiffness region was created between them to compare focal adhesion characteristics and cell functions, taking into account their different time-dependent behavior. Indeed, from a rheological point of view, polyacrylamide behaves like a strong gel (elastically), whereas polydimethylsiloxane like a viscoelastic solid. First, focal adhesion characteristics and dynamics were addressed in terms of material stiffness, then cell spreading area, migration rate and cell mechanical properties were correlated with focal adhesion size and assembly. Focal adhesion size was found to increase in the whole range of stiffness and to be in agreement in the overlapping rigidity region for the investigated materials. Cell mechanics directly correlated with focal adhesion lengths, whereas migration rate followed an inverse correlation. Cell spreading correlated with the substrate stiffness on polyacrylamide hydrogel, while no specific trend was found on polydimethylsiloxane. Substrate mechanics can be considered as a key physical cue that regulates focal adhesion assembly, which in turn governs important cellular properties and functions. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  1. Mercury material-balance in industrial electrolytic cells, by using radioactive mercury (203Hg)

    International Nuclear Information System (INIS)

    Caras, I.; Pasi, M.

    1976-01-01

    A material-balance test for industrial mercury electrolytic cells is described. The test uses the radioactive dilution technique with 203 Hg. The preparation of the 203 Hg from irradiated mercuric oxide is also described. The accuracy of the test is shown to be +-1% for each cell. (author)

  2. Diamond-like carbon as biological compatible material for cell culture and medical application.

    Science.gov (United States)

    Lu, L; Jones, M W; Wu, R L

    1993-01-01

    Ion beam assisted diamond-like carbon (DLC) films have been used for growing the human hematopoietic myeloblastic ML-1 cells and human embryo kidney 293 cells in the control environment. DLC films were directly deposited onto the P-35 plastic dishes by impacting the high kinetic energy (1000 eV) of methane ions at room temperature. The present results showed that both ML-1 and HEK 293 cells continuously grow with and without DLC films. It has demonstrated that human cells proliferated on DLC film with very high viability and DLC material had no toxicity to cultured human ML-1 and HEK 293 cells. We conclude that DLC film is a biological compatible material for potential cell culture matrix and bio-medical applications.

  3. Materialism.

    Science.gov (United States)

    Melnyk, Andrew

    2012-05-01

    Materialism is nearly universally assumed by cognitive scientists. Intuitively, materialism says that a person's mental states are nothing over and above his or her material states, while dualism denies this. Philosophers have introduced concepts (e.g., realization and supervenience) to assist in formulating the theses of materialism and dualism with more precision, and distinguished among importantly different versions of each view (e.g., eliminative materialism, substance dualism, and emergentism). They have also clarified the logic of arguments that use empirical findings to support materialism. Finally, they have devised various objections to materialism, objections that therefore serve also as arguments for dualism. These objections typically center around two features of mental states that materialism has had trouble in accommodating. The first feature is intentionality, the property of representing, or being about, objects, properties, and states of affairs external to the mental states. The second feature is phenomenal consciousness, the property possessed by many mental states of there being something it is like for the subject of the mental state to be in that mental state. WIREs Cogn Sci 2012, 3:281-292. doi: 10.1002/wcs.1174 For further resources related to this article, please visit the WIREs website. Copyright © 2012 John Wiley & Sons, Ltd.

  4. Enhanced photon absorption in spiral nanostructured solar cells using layered 2D materials.

    Science.gov (United States)

    Tahersima, Mohammad H; Sorger, Volker J

    2015-08-28

    Recent investigations of semiconducting two-dimensional (2D) transition metal dichalcogenides have provided evidence for strong light absorption relative to its thickness attributed to high density of states. Stacking a combination of metallic, insulating, and semiconducting 2D materials enables functional devices with atomic thicknesses. While photovoltaic cells based on 2D materials have been demonstrated, the reported absorption is still just a few percent of the incident light due to their sub-wavelength thickness leading to low cell efficiencies. Here we show that taking advantage of the mechanical flexibility of 2D materials by rolling a molybdenum disulfide (MoS(2))/graphene (Gr)/hexagonal boron nitride stack to a spiral solar cell allows for optical absorption up to 90%. The optical absorption of a 1 μm long hetero-material spiral cell consisting of the aforementioned hetero stack is about 50% stronger compared to a planar MoS(2) cell of the same thickness; although the volumetric absorbing material ratio is only 6%. A core-shell structure exhibits enhanced absorption and pronounced absorption peaks with respect to a spiral structure without metallic contacts. We anticipate these results to provide guidance for photonic structures that take advantage of the unique properties of 2D materials in solar energy conversion applications.

  5. 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...

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

    International Nuclear Information System (INIS)

    Gibbons, P.W.; Ramsey, E.B.

    1990-01-01

    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

  7. Human dental pulp cell responses to new calcium silicate-based endodontic materials.

    Science.gov (United States)

    Chen, C C; Shie, M Y; Ding, S J

    2011-09-01

    To evaluate human dental pulp cell responses to radiopaque dicalcium silicate cement and white-coloured mineral trioxide aggregate (WMTA). Flow cytometry was employed to quantify the phase percentage of pulp cell cycle. Alamar Blue was used for real-time and repeated monitoring of cell proliferation. Reverse transcription-polymerase chain reaction was performed to determine gene expression in pulp cells cultured on the cements. The cells cultured on the radiopaque dicalcium silicate cement had similar S and G2 phases in the cell cycle and proliferation to WMTA at all culture times. In addition, the two materials presented the same evolution with similar values in interleukin-1, inducible nitric oxide synthase, alkaline phosphatase, osteocalcin and bone sialoprotein gene expression at all culture times. The dental pulp cell responses to radiopaque dicalcium silicate cement were similar to those reported for WMTA in terms of cell cycle, proliferation, immunocompatibility and osteogenic differentiation. © 2011 International Endodontic Journal.

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

    International Nuclear Information System (INIS)

    Bychkov, Aleksey L.; Ryabchikova, E.I.; Korolev, K.G.; Lomovsky, O.I.

    2012-01-01

    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.

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

    International Nuclear Information System (INIS)

    Tokarz, R.D.; Defferding, L.J.; Adickes, M.D.; Keene, K.E.; Pilger, J.P.; Alzheimer, J.M.; Paxton, M.M.

    1993-10-01

    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

  10. Single cells for forensic DNA analysis--from evidence material to test tube.

    Science.gov (United States)

    Brück, Simon; Evers, Heidrun; Heidorn, Frank; Müller, Ute; Kilper, Roland; Verhoff, Marcel A

    2011-01-01

    The purpose of this project was to develop a method that, while providing morphological quality control, allows single cells to be obtained from the surfaces of various evidence materials and be made available for DNA analysis in cases where only small amounts of cell material are present or where only mixed traces are found. With the SteREO Lumar.V12 stereomicroscope and UV unit from Zeiss, it was possible to detect and assess single epithelial cells on the surfaces of various objects (e.g., glass, plastic, metal). A digitally operated micromanipulator developed by aura optik was used to lift a single cell from the surface of evidence material and to transfer it to a conventional PCR tube or to an AmpliGrid(®) from Advalytix. The actual lifting of the cells was performed with microglobes that acted as carriers. The microglobes were held with microtweezers and were transferred to the DNA analysis receptacles along with the adhering cells. In a next step, the PCR can be carried out in this receptacle without removing the microglobe. Our method allows a single cell to be isolated directly from evidence material and be made available for forensic DNA analysis. © 2010 American Academy of Forensic Sciences.

  11. 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

    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.

  12. 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.

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

    International Nuclear Information System (INIS)

    Desselle, J.C.

    1979-10-01

    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 [fr

  14. Mechanosensing of cells in 3D gel matrices based on natural and synthetic materials.

    Science.gov (United States)

    Shan, Jieling; Chi, Qingjia; Wang, Hongbing; Huang, Qiping; Yang, Li; Yu, Guanglei; Zou, Xiaobing

    2014-11-01

    Cells in vivo typically are found in 3D matrices, the mechanical stiffness of which is important to the cell and tissue-scale biological processes. Although it is well characterized that as to how cells sense matrix stiffness in 2D substrates, the scenario in 3D matrices needs to be explored. Thus, materials that can mimic native 3D environments and possess wide, physiologically relevant elasticity are highly desirable. Natural polymer-based materials and synthetic hydrogels could provide an better 3D platforms to investigate the mechano-response of cells with stiffness comparable to their native environments. However, the limited stiffness range together with interdependence of matrix stiffness and adhesive ligand density are inherent in many kinds of materials, and hinder efforts to demonstrate the true effects contributed by matrix stiffness. These problems have been addressed by the recently emerging exquisitely designed materials based on native matrix components, designer matrices, and synthetic polymers. In this review, a variety of materials with a wide stiffness range that mimic the mechanical environment of native 3D matrices and the independent affection of stiffness for cellular behavior and tissue-level processes are discussed. © 2014 International Federation for Cell Biology.

  15. 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

  16. Thermal Management of Concentrated Multi-Junction Solar Cells with Graphene-Enhanced Thermal Interface Materials

    Directory of Open Access Journals (Sweden)

    Mohammed Saadah

    2017-06-01

    Full Text Available We report results of experimental investigation of temperature rise in concentrated multi-junction photovoltaic solar cells with graphene-enhanced thermal interface materials. Graphene and few-layer graphene fillers, produced by a scalable environmentally-friendly liquid-phase exfoliation technique, were incorporated into conventional thermal interface materials. Graphene-enhanced thermal interface materials have been applied between a solar cell and heat sink to improve heat dissipation. The performance of the multi-junction solar cells has been tested using an industry-standard solar simulator under a light concentration of up to 2000 suns. It was found that the application of graphene-enhanced thermal interface materials allows one to reduce the solar cell temperature and increase the open-circuit voltage. We demonstrated that the use of graphene helps in recovering a significant amount of the power loss due to solar cell overheating. The obtained results are important for the development of new technologies for thermal management of concentrated photovoltaic solar cells.

  17. 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.

  18. 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.

  19. Invited Paper: CIGS-based thin film solar cells and modules: Unique material properties

    Science.gov (United States)

    Nakada, Tokio

    2012-04-01

    Although CIGS solar cells consist of a polycrystalline thin film grown on a glass substrate, more than 20% conversion efficiency has been achieved. The efficiency has reached the same level as polycrystalline silicon solar cells. This high efficiency has not yet been observed in other thin film solar cells including thin film Si and CdTe. Therefore, it is important to understand the mechanisms that allow CIGS solar cells to exhibit high conversion efficiencies. This paper discusses the origin of the high efficiency and demonstrates that it is caused by the unique material properties of CIGS films.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-08-22

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. Recent progress of dopant-free organic hole-transporting materials in perovskite solar cells

    Science.gov (United States)

    Dongxue, Liu; Liu, Yongsheng

    2017-01-01

    Organic-inorganic hybrid perovskite solar cells have undergone especially intense research and transformation over the past seven years due to their enormous progress in conversion efficiencies. In this perspective, we review the latest developments of conventional perovskite solar cells with a main focus on dopant-free organic hole transporting materials (HTMs). Regarding the rapid progress of perovskite solar cells, stability of devices using dopant-free HTMs are also discussed to help readers understand the challenges and opportunities in high performance and stable perovskite solar cells. Project supported by the Scientific Research Starting Foundation for Overseas Introduced Talents of College of Chemistry, Nankai University.

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

    Directory of Open Access Journals (Sweden)

    D. Radhika

    2013-06-01

    Full Text Available 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 section on electrolytes gives an overview of zirconia, lanthanum gallate and ceria based materials. Also, this review article explains the application of different anode, cathode and interconnect materials used for SOFC systems. SOFC can result in better performance with the application of liquid fuels such methanol and ethanol. As a whole, this review article discusses the novel materials suitable for operation of SOFC systems especially for low temperature operation.

  4. Modelling effective dielectric properties of materials containing diverse types of biological cells

    International Nuclear Information System (INIS)

    Huclova, Sonja; Froehlich, Juerg; Erni, Daniel

    2010-01-01

    An efficient and versatile numerical method for the generation of different realistically shaped biological cells is developed. This framework is used to calculate the dielectric spectra of materials containing specific types of biological cells. For the generation of the numerical models of the cells a flexible parametrization method based on the so-called superformula is applied including the option of obtaining non-axisymmetric shapes such as box-shaped cells and even shapes corresponding to echinocytes. The dielectric spectra of effective media containing various cell morphologies are calculated focusing on the dependence of the spectral features on the cell shape. The numerical method is validated by comparing a model of spherical inclusions at a low volume fraction with the analytical solution obtained by the Maxwell-Garnett mixing formula, resulting in good agreement. Our simulation data for different cell shapes suggest that around 1MHz the effective dielectric properties of different cell shapes at different volume fractions significantly deviate from the spherical case. The most pronounced change exhibits ε eff between 0.1 and 1 MHz with a deviation of up to 35% for a box-shaped cell and 15% for an echinocyte compared with the sphere at a volume fraction of 0.4. This hampers the unique interpretation of changes in cellular features measured by dielectric spectroscopy when simplified material models are used.

  5. 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.

  6. 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....

  7. 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. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. 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.

  9. Synthetic Light-Curable Polymeric Materials Provide a Supportive Niche for Dental Pulp Stem Cells.

    Science.gov (United States)

    Vining, Kyle H; Scherba, Jacob C; Bever, Alaina M; Alexander, Morgan R; Celiz, Adam D; Mooney, David J

    2018-01-01

    Dental disease annually affects billions of patients, and while regenerative dentistry aims to heal dental tissue after injury, existing polymeric restorative materials, or fillings, do not directly participate in the healing process in a bioinstructive manner. There is a need for restorative materials that can support native functions of dental pulp stem cells (DPSCs), which are capable of regenerating dentin. A polymer microarray formed from commercially available monomers to rapidly identify materials that support DPSC adhesion is used. Based on these findings, thiol-ene chemistry is employed to achieve rapid light-curing and minimize residual monomer of the lead materials. Several triacrylate bulk polymers support DPSC adhesion, proliferation, and differentiation in vitro, and exhibit stiffness and tensile strength similar to existing dental materials. Conversely, materials composed of a trimethacrylate monomer or bisphenol A glycidyl methacrylate, which is a monomer standard in dental materials, do not support stem cell adhesion and negatively impact matrix and signaling pathways. Furthermore, thiol-ene polymerized triacrylates are used as permanent filling materials at the dentin-pulp interface in direct contact with irreversibly injured pulp tissue. These novel triacrylate-based biomaterials have potential to enable novel regenerative dental therapies in the clinic by both restoring teeth and providing a supportive niche for DPSCs. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. High Performance Nano-Crystalline Oxide Fuel Cell Materials. Defects, Structures, Interfaces, Transport, and Electrochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Barnett, Scott [Northwestern Univ., Evanston, IL (United States); Poeppelmeier, Ken [Northwestern Univ., Evanston, IL (United States); Mason, Tom [Northwestern Univ., Evanston, IL (United States); Marks, Lawrence [Northwestern Univ., Evanston, IL (United States); Voorhees, Peter [Northwestern Univ., Evanston, IL (United States)

    2016-09-07

    This project addresses fundamental materials challenges in solid oxide electrochemical cells, devices that have a broad range of important energy applications. Although nano-scale mixed ionically and electronically conducting (MIEC) materials provide an important opportunity to improve performance and reduce device operating temperature, durability issues threaten to limit their utility and have remained largely unexplored. Our work has focused on both (1) understanding the fundamental processes related to oxygen transport and surface-vapor reactions in nano-scale MIEC materials, and (2) determining and understanding the key factors that control their long-term stability. Furthermore, materials stability has been explored under the “extreme” conditions encountered in many solid oxide cell applications, i.e, very high or very low effective oxygen pressures, and high current density.

  11. Corrosion of materials in Molten Carbonate Fuel Cells (MCFC): Literature review

    Science.gov (United States)

    1987-01-01

    Molten carbonate fuel cell (MCFC) separator plates are subjected to corrosive environments. This review focuses on the most comprehensive compiled available data from the major government contractors like ERC and UTC, together with a basic review of alloys resistant to oxidation, sulfidation, carburization, and hot corrosion. Results of this review are used in selecting test materials for the current program. A number of metal oxides were examined. This review discusses the tests performed by UTC and ERC on separator plate materials.

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

    International Nuclear Information System (INIS)

    Lundeen, J.E.

    1994-01-01

    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

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

    International Nuclear Information System (INIS)

    1980-01-01

    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.)

  14. Influence of interface preparation on minority carrier lifetime for low bandgap tandem solar cell materials

    Energy Technology Data Exchange (ETDEWEB)

    Szabo, Nadine; Sagol, B. Erol; Seidel, Ulf; Schwarzburg, Klaus; Hannappel, Thomas [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Berlin (Germany)

    2010-07-01

    III-V semiconductor compounds grown by MOVPE are implemented in todays state-of-the-art third generation multi-junction solar cells. The current record multi junction solar cell grown on germanium, having Ge, Ga(In)As and GaInP as subcells, reached a record efficiency of 41.6%. The efficiency of these multi junction solar cells could be significantly increased, if its low bandgap Ge subcell would be replaced by a more efficient tandem. For this purpose the low bandgap materials InGaAs and InGaAsP are suitable. The bandgap composition of these materials allows a better yield of the solar spectrum. Based on InGaAs/InGaAsP absorber materials we have developed a low bandgap tandem solar cell with optimized bandgaps. Results of time resolved photoluminescence (TRPL) for the IR-bandgap compounds InGaAsP (1.03 eV)/InGaAs (0.73 eV) are presented. The lifetime of minority carriers is one of the most important properties of solar cell absorber materials. We show on the example of the low band gap tandem cell how the choice of the materials, the quality of the bulk, the optimization of the band gap energies and the preparation of the critical interfaces are essential to build a high efficiency solar cell. The quality of the bulk and the preparation of the critical interfaces are essential for the growth of the double heterostructure (DHS).

  15. Stretchable living materials and devices with hydrogel-elastomer hybrids hosting programmed cells.

    Science.gov (United States)

    Liu, Xinyue; Tang, Tzu-Chieh; Tham, Eléonore; Yuk, Hyunwoo; Lin, Shaoting; Lu, Timothy K; Zhao, Xuanhe

    2017-02-28

    Living systems, such as bacteria, yeasts, and mammalian cells, can be genetically programmed with synthetic circuits that execute sensing, computing, memory, and response functions. Integrating these functional living components into materials and devices will provide powerful tools for scientific research and enable new technological applications. However, it has been a grand challenge to maintain the viability, functionality, and safety of living components in freestanding materials and devices, which frequently undergo deformations during applications. Here, we report the design of a set of living materials and devices based on stretchable, robust, and biocompatible hydrogel-elastomer hybrids that host various types of genetically engineered bacterial cells. The hydrogel provides sustainable supplies of water and nutrients, and the elastomer is air-permeable, maintaining long-term viability and functionality of the encapsulated cells. Communication between different bacterial strains and with the environment is achieved via diffusion of molecules in the hydrogel. The high stretchability and robustness of the hydrogel-elastomer hybrids prevent leakage of cells from the living materials and devices, even under large deformations. We show functions and applications of stretchable living sensors that are responsive to multiple chemicals in a variety of form factors, including skin patches and gloves-based sensors. We further develop a quantitative model that couples transportation of signaling molecules and cellular response to aid the design of future living materials and devices.

  16. Research progress on organic-inorganic halide perovskite materials and solar cells

    Science.gov (United States)

    Ono, Luis K.; Qi, Yabing

    2018-03-01

    Owing to the intensive research efforts across the world since 2009, perovskite solar cell power conversion efficiencies (PCEs) are now comparable or even better than several other photovoltaic (PV) technologies. In this topical review article, we review recent progress in the field of organic-inorganic halide perovskite materials and solar cells. We associate these achievements with the fundamental knowledge gained in the perovskite research. The major recent advances in the fundamental perovskite material and solar cell research are highlighted, including the current efforts in visualizing the dynamical processes (in operando) taking place within a perovskite solar cell under operating conditions. We also discuss the existing technological challenges. Based on a survey of recently published works, we point out that to move the perovskite PV technology forward towards the next step of commercialization, what perovskite PV technology need the most in the coming next few years is not only further PCE enhancements, but also up-scaling, stability, and lead-toxicity.

  17. 14th Workshop on Crystalline Silicon Solar Cells& Modules: Materials and Processes; Extended Abstracts and Papers

    Energy Technology Data Exchange (ETDEWEB)

    Sopori, B. L.

    2004-08-01

    The 14th Workshop will provide a forum for an informal exchange of technical and scientific information between international researchers in the photovoltaic and relevant non-photovoltaic fields. It will offer an excellent opportunity for researchers in private industry and at universities to prioritize mutual needs for future collaborative research. The workshop is intended to address the fundamental properties of PV silicon, new solar cell designs, advanced solar cell processing techniques, and cell-related module issues. A combination of oral presentations by invited speakers, poster sessions, and discussion sessions will review recent advances in crystal growth, new cell designs, new processes and process characterization techniques, cell fabrication approaches suitable for future manufacturing demands, and solar cell encapsulation. This year's theme, ''Crystalline Si Solar Cells: Leapfrogging the Barriers,'' reflects the continued success of crystalline Si PV in overcoming technological barriers to improve solar cell performance and lower the cost of Si PV. The workshop will consist of presentations by invited speakers, followed by discussion sessions. In addition, there will be two poster sessions presenting the latest research and development results. Some presentations will address recent technologies in the microelectronics field that may have a direct bearing on PV. The sessions will include: Advances in crystal growth and material issues; Impurities and defects; Dynamics during device processing; Passivation; High-efficiency Si solar cells; Advanced processing; Thin Si solar cells; and Solar cell reliability and module issues.

  18. Periodontal materials and cell biology for guided tissue and bone regeneration.

    Science.gov (United States)

    Andrei, Mihai; Dinischiotu, Anca; Didilescu, Andreea Cristiana; Ionita, Daniela; Demetrescu, Ioana

    2018-03-01

    The present review is intended to find links between periodontal materials of the dentomaxillary apparatus and cell biology at the beginning of a century fraught with various forms of periodontal diseases and needing new treatment strategies. The manuscript has two different parts. The first describes the anatomy of tooth supporting structures, as well as related pathologies. The second part is related to cell and molecular biology in the context of periodontal regeneration. Copyright © 2017. Published by Elsevier GmbH.

  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. Graphene-enhanced thermal interface materials for heat removal from photovoltaic solar cells

    Science.gov (United States)

    Saadah, M.; Gamalath, D.; Hernandez, E.; Balandin, A. A.

    2016-09-01

    The increase in the temperature of photovoltaic (PV) solar cells affects negatively their power conversion efficiency and decreases their lifetime. The negative effects are particularly pronounced in concentrator solar cells. Therefore, it is crucial to limit the PV cell temperature by effectively removing the excess heat. Conventional thermal phase change materials (PCMs) and thermal interface materials (TIMs) do not possess the thermal conductivity values sufficient for thermal management of the next generation of PV cells. In this paper, we report the results of investigation of the increased efficiency of PV cells with the use of graphene-enhanced TIMs. Graphene reveals the highest values of the intrinsic thermal conductivity. It was also shown that the thermal conductivity of composites can be increased via utilization of graphene fillers. We prepared TIMs with up to 6% of graphene designed specifically for PV cell application. The solar cells were tested using the solar simulation module. It was found that the drop in the output voltage of the solar panel under two-sun concentrated illumination can be reduced from 19% to 6% when grapheneenhanced TIMs are used. The proposed method can recover up to 75% of the power loss in solar cells.

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

    Science.gov (United States)

    Lindsey, Jonathan S [Raleigh, NC; Chinnasamy, Muthiah [Raleigh, NC; Fan, Dazhong [Raleigh, NC

    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.

  2. 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.

  3. Artificial inorganic Biohybrids: the functional combination of microorganisms and cells with inorganic materials.

    Science.gov (United States)

    Holzmeister, Ib; Schamel, Martha; Groll, Jürgen; Gbureck, Uwe; Vorndran, Elke

    2018-04-23

    Biohybrids can be defined as the functional combination of proteins, viable cells or microorganisms with non-biological materials. This article reviews recent findings on the encapsulation of microorganisms and eukaryotic cells in inorganic matrices such as silica gels or cements. The entrapment of biological entities into a support material is of great benefit for processing since the encapsulation matrix protects sensitive cells from shear forces, unfavourable pH changes, or cytotoxic solvents, avoids culture-washout, and simplifies the separation of formed products. After reflecting general aspects of such an immobilization as well as the chemistry of the inorganic matrices, we focused on manufacturing aspects and the application of such biohybrids in biotechnology, medicine as well as in environmental science and for civil engineering purpose. The encapsulation of living cells and microorganisms became an intensively studied and rapidly expanding research field with manifold applications in medicine, bio- and environmental technology, or civil engineering. Here, the use of silica or cements as encapsulation matrices have the advantage of a higher chemical and mechanical resistance towards harsh environmental conditions during processing compared to their polymeric counterparts. In this perspective, the article gives an overview about the inorganic material systems used for cell encapsulation, followed by reviewing the most important applications. The future may lay in a combination of the currently achieved biohybrid systems with additive manufacturing techniques. In a longer perspective, this would enable the direct printing of cell loaded bioreactor components. Copyright © 2018. Published by Elsevier Ltd.

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

    DEFF Research Database (Denmark)

    Larsen, Mikkel Juul

    samples. Generally, the measurements using this method suffered from poor electrode homogeneity due to the problem of dispersing the CNT and CNF material on the electrode disc. For the carbon samples the peroxide percentage was 25–75 % at 0.066 V vs. the dynamic hydrogen electrode (DHE), but no ORR......In order to ensure high utilization of the catalyst material in a polymer electrolyte membrane fuel cell (PEMFC) it is usually fixed in the form of nanoparticles on a supporting material. The catalyst is platinum or a platinum alloy, and the commonly used support is carbon black (CB). Although...... structured carbon forms such as graphitized CBs, carbon nanotubes (CNTs), and carbon nanofibres (CNFs). This thesis concerns the investigation of an array of different materials which may prospec-tively replace the conventional materials used in the catalyst. The study comprised 13 carbon samples which...

  5. Graphene-Based Materials for Photoanodes in Dye-Sensitized Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Xiaoru [Department of Mechanical Engineering, University of Wisconsin-Milwaukee, Milwaukee, WI (United States); Lu, Ganhua [Department of Mechanical Engineering, University of Alaska Anchorage, Anchorage, AK (United States); Chen, Junhong, E-mail: jhchen@uwm.edu [Department of Mechanical Engineering, University of Wisconsin-Milwaukee, Milwaukee, WI (United States)

    2015-12-14

    This article reviews the research on the use of graphene and related materials in the photoanode of dye-sensitized solar cells (DSSCs). Graphene-based materials, such as pristine graphene, graphene oxide, and reduced graphene oxide, have properties attractive for various components of the DSSC photoanode. We first provide a brief introduction to graphene properties and analyze requirements for making a high-performance photoanode. Then, we introduce applications of graphene-based materials in each part of the DSSC photoanode, i.e., the transparent conducting electrode, the sensitizing material, and the semiconducting layer. Particularly, we discuss how the incorporation of graphene-based materials in those components can enhance the photoanode performance. It is clear that the outstanding properties of graphene, such as the fast electron transfer ability, high Young’s modulus, and good transparency, benefit DSSC photoanode research, and doping or surface modifications of graphene nanosheets with other materials can also improve the photoanode and, thus, the resulting cell performance. Finally, we present an outlook for current issues and further trends for using graphene materials in DSSC photoanodes.

  6. Graphene-based Materials for Photoanodes in Dye-sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Xiaoru eGuo

    2015-12-01

    Full Text Available This article reviews the research on the use of graphene and related materials in the photoanode of dye-sensitized solar cells (DSSCs. Graphene-based materials, such as pristine graphene, graphene oxide, and reduced graphene oxide, have properties attractive for various components of the DSSC photoanode. We first provide a brief introduction to graphene properties and analyze requirements for making a high-performance photoanode. Then we introduce applications of graphene-based materials in each part of the DSSC photoanode, i.e., the transparent conducting electrode, the sensitizing material, and the semiconducting layer. Particularly, we discuss how the incorporation of graphene-based materials in those components can enhance the photoanode performance. It is clear that the outstanding properties of graphene, such as the fast electron transfer ability, high Young’s modulus, and good transparency, benefit DSSC photoanode research, and doping or surface modifications of graphene nanosheets with other materials can also improve the photoanode and thus the resulting cell performance. Finally, we present an outlook for current issues and further trends for using graphene materials in DSSC photoanodes.

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

    International Nuclear Information System (INIS)

    Geelen, H.

    1994-04-01

    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. Investigation of engineered bacterial adhesins for opportunity to interface cells with abiotic materials

    Science.gov (United States)

    Terrell, Jessica L.; Dong, Hong; Holthoff, Ellen L.; Small, Meagan C.; Sarkes, Deborah A.; Hurley, Margaret M.; Stratis-Cullum, Dimitra N.

    2016-05-01

    The convenience of cellular genetic engineering has afforded the power to build `smart' synthetic biological tools with novel applications. Here, we have explored opportunities to hybridize engineered cells with inorganic materials toward the development of 'living' device-compatible systems. Cellular structural biology is engineerable based on the ability to rewrite genetic code to generate recombinant, foreign, or even unnatural proteins. With this capability on the biological end, it should be possible to achieve superior abio-compatibility with the inorganic materials that compose current microfabricated technology. This work investigated the hair-like appendages of Escherichia coli known as Type 1 fimbriae that enable natural adhesion to glycosylated substrates. Sequence alterations within the fimbrial gene cluster were found to be well-tolerated, evidenced by tagging the fimbriae with peptide-based probes. As a further development, fimbriae tips could be reconfigured to, in turn, alter cell binding. In particular, the fimbriae were fused with a genetically optimized peptide-for-inorganics to enable metal binding. This work established methodologies to systematically survey cell adhesion properties across a suite of fimbriae-modified cell types as well as to direct patterned cell adhesion. Cell types were further customized for added complexity including turning on secondary gene expression and binding to gold surfaces. The former demonstrates potential for programmable gene switches and the latter for interfacing biology with inorganic materials. In general, the incorporation of 'programmed' cells into devices can be used to provide the feature of dynamic and automated cell response. The outcomes of this study are foundational toward the critical feature of deliberate positioning of cells as configurable biocomponentry. Overall, cellular integration into bioMEMs will yield advanced sensing and actuation.

  9. Produksi dan Karakterisasi Antibodi Monoklonal Anti-Cysticercus cellulosae (PRODUCTION AND CHRACTERIZATION OF MONOCLONAL ANTIBODIES AGAINST CYSTICERCUS CELLULOSAE

    Directory of Open Access Journals (Sweden)

    Ida Bagus Ngurah Swacita

    2015-10-01

    Full Text Available The purpose of this study is to make a monoclonal antibody against- Cysticercus cellulosae and itscharacterization. Samples antigen prepared from T. solium larvae (C. cellulosae was then used to immunizeBalb/c. The immune response of mice assessed by ELISA test, then the lymphocytes of mice used for theproduction of monoclonal antibodies (MoAb. Origin lymphocytes of mice that produce antibodies againstC. cellulosae antigen, fused with myeloma cells (NS1. Results fusion of two cells produces hybrid cellscalled hybridomas; cells are then screened by ELISA test. Hybridoma cells that produce only MoAb, usedto produce large quantities in vitro. Characterization of MoAb against-C.cellulosae was tested by usingELISA and Western blotting. Mice were immunized with C.cellulosae antigen showed an immune responseproducing antibodies to C.cellulosae. Based on the results of fusion, produced a total of 51 hybridoma cellclones and after being screened, only three clones of hybridoma cells that produced MoAb against–C.cellulosae. MoAb produced, named after the hole where the growth of the ELISA micro plate, the BE6,BE7, and EE9. Characteristics of this MoAb capable of tracking cellulosae of fluid larvae and recognizeantigen protein bands with molecular weight 78kDa.

  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. Reticulated vitreous carbon: a useful material for cell adhesion and tissue invasion

    Directory of Open Access Journals (Sweden)

    MK Pec

    2010-10-01

    Full Text Available Diverse carbon materials have been used for tissue engineering and clinical implant applications with varying success. In this study, commercially available reticulated vitreous carbon (RVC foams were tested in vitro and in vivo for compatibility with primary cell adhesion and tissue repair. Pores sizes were determined as 279 ± 98 µm. No hydroxyapatite deposition was detected after immersion of the foams in simulated body fluid. Nonetheless, RVC provided an excellent support for adhesion of mesenchymal stem cells (MSCs as well as primary chondrocytes without any surface pre-treatment. Live cell quantification revealed neutral behaviour of the material with plastic adhered chondrocytes but moderate cytotoxicity with MSCs. Yet, rabbit implanted foams exhibited good integration in subcutaneous pockets and most importantly, total defect repair in bone. Probably due to the stiffness of the material, incompatibility with cartilage regeneration was found. Interestingly and in contrast to several other carbon materials, we observed a total lack of foreign body reactions. Our results and its outstanding porous interconnectivity and availability within a wide range of pore sizes convert RVC into an attractive candidate for tissue engineering applications in a variety of bone models and for ex vivo cell expansion for regenerative medical applications.

  12. 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...

  13. The performance of human dental pulp stem cells on different three-dimensional scaffold materials.

    NARCIS (Netherlands)

    Zhang, W.; Walboomers, X.F.; Kuppevelt, A.H.M.S.M. van; Daamen, W.F.; Bian, Z.; Jansen, J.A.

    2006-01-01

    The aim of this study was to investigate the in vitro and in vivo behavior of human dental pulp stem cells (DPSCs) isolated from impacted third molars, when seeded onto different 3-dimensional (3-D) scaffold materials: i.e. a spongeous collagen, a porous ceramic, and a fibrous titanium mesh.

  14. Neural Stem Cells and Its Derivatives as a New Material for Melanin Inhibition.

    Science.gov (United States)

    Hwang, Insik; Hong, Sunghoi

    2017-12-22

    The pigment molecule, melanin, is produced from melanosomes of melanocytes through melanogenesis, which is a complex process involving a combination of chemical and enzymatically catalyzed reactions. The synthesis of melanin is primarily influenced by tyrosinase (TYR), which has attracted interest as a target molecule for the regulation of pigmentation or depigmentation in skin. Thus, direct inhibitors of TYR activity have been sought from various natural and synthetic materials. However, due to issues with these inhibitors, such as weak or permanent ability for depigmentation, allergy, irritant dermatitis and rapid oxidation, in vitro and in vivo, the development of new materials that inhibit melanin production is essential. A conditioned medium (CM) derived from stem cells contains many cell-secreted factors, such as cytokines, chemokines, growth factors and extracellular vesicles including exosomes. In addition, the secreted factors could negatively regulate melanin production through stimulation of a microenvironment of skin tissue in a paracrine manner, which allows the neural stem cell CM to be explored as a new material for skin depigmentation. In this review, we will summarize the current knowledge regulating depigmentation, and discuss the potential of neural stem cells and their derivatives, as a new material for skin depigmentation.

  15. 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

  16. 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…

  17. The influence of surface biological modification of selected implant materials on the viability of bone cells

    Czech Academy of Sciences Publication Activity Database

    Pešáková, V.; Hulejová, H.; Riedel, Tomáš; Kubies, Dana

    2007-01-01

    Roč. 13, č. 7 (2007), s. 1764 ISSN 1076-3279. [Annual Meeting of the Tissue Engineering & Regenerative Medicine Society (TERMIS-EU Meeting). 04.09.2007-07.09.2007, London] Institutional research plan: CEZ:AV0Z40500505 Keywords : implant materials * bone cells Subject RIV: CE - Biochemistry

  18. Photovoltaic material and device measurements workshop: focus on polycrystalline thin film cells

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-01-01

    The general purpose of the workshop was to accelerate the development of thin film solar cells by improving the versatility and reliability of material and device measurement techniques. Papers were presented under the following sessions: structural/chemical session; optical/electro-optical session; charge transport session; and poster session. Each paper was processed for EDB.

  19. Virtual modeling of polycrystalline structures of materials using particle packing algorithms and Laguerre cells

    Science.gov (United States)

    Morfa, Carlos Recarey; Farias, Márcio Muniz de; Morales, Irvin Pablo Pérez; Navarra, Eugenio Oñate Ibañez de; Valera, Roberto Roselló

    2017-06-01

    The influence of the microstructural heterogeneities is an important topic in the study of materials. In the context of computational mechanics, it is therefore necessary to generate virtual materials that are statistically equivalent to the microstructure under study, and to connect that geometrical description to the different numerical methods. Herein, the authors present a procedure to model continuous solid polycrystalline materials, such as rocks and metals, preserving their representative statistical grain size distribution. The first phase of the procedure consists of segmenting an image of the material into adjacent polyhedral grains representing the individual crystals. This segmentation allows estimating the grain size distribution, which is used as the input for an advancing front sphere packing algorithm. Finally, Laguerre diagrams are calculated from the obtained sphere packings. The centers of the spheres give the centers of the Laguerre cells, and their radii determine the cells' weights. The cell sizes in the obtained Laguerre diagrams have a distribution similar to that of the grains obtained from the image segmentation. That is why those diagrams are a convenient model of the original crystalline structure. The above-outlined procedure has been used to model real polycrystalline metallic materials. The main difference with previously existing methods lies in the use of a better particle packing algorithm.

  20. Virtual modeling of polycrystalline structures of materials using particle packing algorithms and Laguerre cells

    Science.gov (United States)

    Morfa, Carlos Recarey; Farias, Márcio Muniz de; Morales, Irvin Pablo Pérez; Navarra, Eugenio Oñate Ibañez de; Valera, Roberto Roselló

    2018-04-01

    The influence of the microstructural heterogeneities is an important topic in the study of materials. In the context of computational mechanics, it is therefore necessary to generate virtual materials that are statistically equivalent to the microstructure under study, and to connect that geometrical description to the different numerical methods. Herein, the authors present a procedure to model continuous solid polycrystalline materials, such as rocks and metals, preserving their representative statistical grain size distribution. The first phase of the procedure consists of segmenting an image of the material into adjacent polyhedral grains representing the individual crystals. This segmentation allows estimating the grain size distribution, which is used as the input for an advancing front sphere packing algorithm. Finally, Laguerre diagrams are calculated from the obtained sphere packings. The centers of the spheres give the centers of the Laguerre cells, and their radii determine the cells' weights. The cell sizes in the obtained Laguerre diagrams have a distribution similar to that of the grains obtained from the image segmentation. That is why those diagrams are a convenient model of the original crystalline structure. The above-outlined procedure has been used to model real polycrystalline metallic materials. The main difference with previously existing methods lies in the use of a better particle packing algorithm.

  1. Measurement of properties of sealant materials for solid oxide fuel cell systems

    International Nuclear Information System (INIS)

    Boersma, R.J.; Sammes, N.M.; Zhang, Y.

    1998-01-01

    Thermal expansion of ceramic materials, ceramic cements and steels was studied, and their compatibility with materials used in the SOFC system was evaluated. A number of ceramic cements, a glass paste and a glass ceramic were examined to identify their potential as a sealing material in a tubular fuel cell system. Thermal expansion coefficients of these materials were compared for thermal matching with materials employed in the fuel cell construction, such as yttria stabilised with 8 mole% zirconia (8YSZ) and stainless steel. A reasonable match was found for Macor, a glass ceramic, with one of the steel samples studied and with 8YSZ. Candidate sealants were tested for bonding quality, which made it evident that the ceramic cements had to be discarded. Good bonds between Macor and one of the steel samples and Macor and 8YSZ were formed, resulting in a gas tight seal. Uncertainty remains regarding the long term effect of the interface reactions between steel and Macor. Exposure of the Macor and a steel-Macor-8YSZ assembly to the different fuel cell gas atmospheres revealed that the Macor reacts with hydrogen, the long term effect of which is also unknown. Copyright (1998) Australasian Ceramic Society

  2. 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.

  3. 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

    MHOCT) and unsubstituted polythiophene (PT) were used, the latter of which results from thermo cleaving the former at 310 °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......: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...

  4. Simulation of perovskite solar cell with P3HT hole-transporting materials

    Science.gov (United States)

    Karimi, Elham; Ghorashi, Seyed Mohamad Bagher

    2017-07-01

    The performance (PCE) of perovskite solar cells was investigated using the simulation programs solar cell capacitance simulator and analysis of microelectronic and photonic structures-1-D. This paper entailed a study of the effects of hole density concentrations, defect density, thickness of perovskite active layers, P3HT hole-transporting material (HTM) layer thickness, hole mobility, working temperature, and varying illumination intensity on the PCE, of open-circuit voltage, fill factor, short-circuit current density, and the simulation of J-V curves solar cells for varying illumination intensity. Then, J-V characteristics and quantum efficiency were calculated for different thickness absorbers and HTM layers. The simulation results showed an optimal value for the absorber layer thickness and for the HTM layer. Also, a rise in the temperature had a strong effect on the perovskite solar cells PCE. These simulation results serve to provide several important guidelines for feasible fabrication of higher-PCE perovskite solar cells.

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

    DEFF Research Database (Denmark)

    Søndergaard, Roar

    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...... 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...... 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...

  6. 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

  7. 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.

  8. 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

    2016-01-08

    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. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. A PEM fuel cell based on electrocatalyst and membrane materials modified by PANAM dendrimers

    Energy Technology Data Exchange (ETDEWEB)

    Ledesma-Garcia, J.; Chapman, T.W.; Godinez, L.A. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, Queretaro (Mexico)

    2008-10-15

    Due to its high energy conversion efficiency and low emission of pollutants, fuel-cell technology has been generally recognized as a key twenty-first century energy source. For polymer electrolyte membrane fuel cells (PEMFC), it has been found that platinum and its alloys exhibit the best electrocatalytic activity for oxygen reduction. The highest electrocatalytic activity of platinum and its alloys can be achieved when the particles are produced in the nanometer range. In this context, organic molecules have been adopted as templates to control the size of metal nanoparticles. Dendrimers, in particular, have shown promising properties for this application, and strategies that include direct adsorption, electrostatic attachment and covalent bonding have been developed for connecting metal-bearing dendrimers to conducting substrates. This paper reported on the preliminary results of a study that involved the construction and testing of a hydrogen-oxygen PEM fuel cell based on carbon-fiber-paper electrodes coated with hydroxyl-terminated dendrimers that encapsulated nanoparticles of platinum. This prototype cell also employed an ion exchange membrane comprising a cellulose acetate filter functionalized with proton-exchanging dendrimers. A proton-exchange membrane was prepared by binding duplex amine-carboxylate dendrimers to a cellulose-acetate support. With these dendrimer-based materials, a hydrogen-oxygen fuel cell was assembled and the performance compared with cells prepared with Nafion-based membranes. The voltage-current profiles and the power-density curves from the new cell provide encouragement to continue work with these dendrimer-modified materials. The paper discussed the experimental methods, with particular reference to materials; electrode preparation and characterization; proton-exchange membrane preparation; and PEM fuel-cell assembly and testing. It was concluded that the use of the dendritic macromolecules as supports for the nanoparticulate

  10. Strategies for increasing the efficiency of heterojunction organic solar cells: material selection and device architecture.

    Science.gov (United States)

    Heremans, Paul; Cheyns, David; Rand, Barry P

    2009-11-17

    Thin-film blends or bilayers of donor- and acceptor-type organic semiconductors form the core of heterojunction organic photovoltaic cells. Researchers measure the quality of photovoltaic cells based on their power conversion efficiency, the ratio of the electrical power that can be generated versus the power of incident solar radiation. The efficiency of organic solar cells has increased steadily in the last decade, currently reaching up to 6%. Understanding and combating the various loss mechanisms that occur in processes from optical excitation to charge collection should lead to efficiencies on the order of 10% in the near future. In organic heterojunction solar cells, the generation of photocurrent is a cascade of four steps: generation of excitons (electrically neutral bound electron-hole pairs) by photon absorption, diffusion of excitons to the heterojunction, dissociation of the excitons into free charge carriers, and transport of these carriers to the contacts. In this Account, we review our recent contributions to the understanding of the mechanisms that govern these steps. Starting from archetype donor-acceptor systems of planar small-molecule heterojunctions and solution-processed bulk heterojunctions, we outline our search for alternative materials and device architectures. We show that non-planar phthalocynanines have appealing absorption characteristics but also have reduced charge carrier transport. As a result, the donor layer needs to be ultrathin, and all layers of the device have to be tuned to account for optical interference effects. Using these optimization techniques, we illustrate cells with 3.1% efficiency for the non-planar chloroboron subphthalocyanine donor. Molecules offering a better compromise between absorption and carrier mobility should allow for further improvements. We also propose a method for increasing the exciton diffusion length by converting singlet excitons into long-lived triplets. By doping a polymer with a

  11. Dual Control Cell Reaction Ensemble Molecular Dynamics: A Method for Simulations of Reactions and Adsorption in Porous Materials

    National Research Council Canada - National Science Library

    Lisal, Martin; Brennan, John K; Smith, William R; Siperstein, Flor R

    2006-01-01

    .... The method, termed the dual control cell reaction ensemble molecular dynamics method, allows for the calculation of both equilibrium and nonequilibrium transport properties in porous materials...

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

    DEFF Research Database (Denmark)

    Veltzé, Sune

    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......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...... black support materials for low platinum containing electrocatalyst. This is partly due to their high electronic conductivity. Partly due to their high surface area needed for the dispersion of nanoparticulate metal-clusters. In addition carbon nano-structures (CNF, SWCNT, MWCNT etc.) are more durable...

  13. Interactions Between Biological Cells and Layered Double Hydroxides: Towards Functional Materials.

    Science.gov (United States)

    Forano, Claude; Bruna, Felipe; Mousty, Christine; Prevot, Vanessa

    2018-03-08

    This review highlights the current research on the interactions between biological cells and Layered Double Hydroxides (LDH). The as-prepared biohybrid materials appear extremely attractive in diverse fields of application relating to health care, environment and energy production. We describe how thanks to the main features of biological cells and LDH layers, various strategies of assemblies can be carried out for constructing smart biofunctional materials. The interactions between the two components are described with a peculiar attention to the adsorption, biocompatibilization, LDH layer internalization, antifouling and antimicrobial properties. The most significant achievements including authors' results, involving biological cells and LDH assemblies in waste water treatment, bioremediation and bioenergy generation are specifically addressed. © 2018 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Recent development of carbon nanotubes materials as counter electrode for dye-sensitized solar cells

    Directory of Open Access Journals (Sweden)

    M. Malekshahi Byranvand

    2016-01-01

    Full Text Available Dye-sensitized solar cells present promising low-cost alternatives to the conventional Silicon (Si-based solar cells. The counter electrode  generally consists of Pt deposited onto FTO plate. Since Pt is rare and expensive metal, nanostructured carbonaceous materials have been widely investigated as a promising alternative to replace it. Carbon nanotubes  have shown significant properties such as cost-effectiveness, environmental friendliness, availability, corrosion resistance and excellent catalytic activity towards the redox species make them ideal for replacing Pt in the CEs of DSCs. The review presented below gives a succinct summary of the Carbon nanotubes materials in use as counter electrode  in dye-sensitized solar cells .

  15. 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.

  16. Suitability of granular carbon as an anode material for sediment microbial fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Arends, Jan B.A.; Blondeel, Evelyne; Boon, Nico; Verstraete, Willy [Ghent Univ. (Belgium). Faculty of Bioscience Engineering; Tennison, Steve R. [Mast Carbon International Ltd., Basingstoke, Hampshire (United Kingdom)

    2012-08-15

    Purpose: Sediment microbial fuel cells (S-MFCs) are bio-electrochemical devices that are able to oxidize organic matter directly into harvestable electrical power. The flux of organic matter into the sediment is rather low; therefore, other researchers have introduced plants for a continuous supply of organic matter to the anode electrode. Until now only interconnected materials have been considered as anode materials in S-MFCs. Here, granular carbon materials were investigated for their suitability as an anode material in S-MFCs. Materials and methods: Laboratory microcosms with eight different electrode materials (granules, felts and cloths) were examined with controlled organic matter addition under brackish conditions. Current density, organic matter removal and microbial community composition were monitored using 16S rRNA gene PCR followed by denaturing gradient gel electrophoresis (DGGE). The main parameters investigated were the influence of the amount of electrode material applied to the sediment, the size of the granular material and the electrode configuration. Results and discussion: Felt material had an overall superior performance in terms of current density per amount of applied electrode material; felt and granular anode obtained similar current densities (approx. 50-60 mA m{sup -2}), but felt materials required 29 % less material to be applied. Yet, when growing plants, granular carbon is more suited because it is considered to restore, upon disturbance, the electrical connectivity within the anode compartment. Small granules (0.25-0.5 mm) gave the highest current density compared to larger granules (1-5 mm) of the same material. Granules with a rough surface had a better performance compared to smooth granules of the same size. The different granular materials lead to a selection of distinct microbial communities for each material, as shown by DGGE. Conclusions: Granular carbon is suitable as an anode material for S-MFCs. This opens the possibility

  17. 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.

  18. 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 studied using simplified geometry point-contact electrodes. Unique phenomena were observed for some of the materials - they decomposed into multiple phases and formed a nanostructured surface upon exposure to operating conditions (in certain reducing atmospheres). The new phases and surface features...... 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...

  19. Near infrared organic semiconducting materials for bulk heterojunction and dye-sensitized solar cells.

    Science.gov (United States)

    Singh, Surya Prakash; Sharma, G D

    2014-06-01

    Dye sensitized solar cells (DSSCs) and bulk heterojunction (BHJ) solar cells have been the subject of intensive academic interest over the past two decades, and significant commercial effort has been directed towards this area with the vison of developing the next generation of low cost solar cells. Materials development has played a vital role in the dramatic improvement of both DSSC and BHJ solar cell performance in the recent years. Organic conjugated polymers and small molecules that absorb solar light in the visible and near infrared (NIR) regions represent a class of emering materials and show a great potential for the use of different optoelectronic devices such as DSSCs and BHJ solar cells. This account describes the emering class of near infrared (NIR) organic polymers and small molecules having donor and acceptors units, and explores their potential applications in the DSSCs and BHJ solar cells. Copyright © 2014 The Chemical Society of Japan and Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. 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.

  1. Karakterisasi Tepung Konjak Dari Tanaman Iles-iles (Amorphophallus Oncophyllus) Di Daerah Gunung Kreo Semarang Jawa Tengah

    OpenAIRE

    Akbar, Hafiz; Supriyanto, Agus; Haryani, Kristinah

    2013-01-01

    Indonesia has many kinds of plants iles-iles (Amorphophallus oncophyllus). In this study, using raw materials derived from the Goa Kreo, Semarang, Central Java, the area has two types of iles-iles, namely A. oncophyllus and A. variabillis. Plants iles-iles (konjac) contains a fairly high Glukomannan, glukomannan is a polysaccharide composed of units of D-glucose and D-mannose. In this study intended to determine the content of glucomannan plant iles-iles in Goa Kreo. By using gravimetric meth...

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

    Science.gov (United States)

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

    2013-01-07

    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.

  3. Carbon materials for enhancing charge transport in the advancements of perovskite solar cells

    Science.gov (United States)

    Hu, Ruiyuan; Chu, Liang; Zhang, Jian; Li, Xing'ao; Huang, Wei

    2017-09-01

    Organic-inorganic halide perovskite solar cells (PSCs) have become a new favorite in the photovoltaic field, due to the boosted efficiency up to 22.1%. Despite a flow of achievements, there are certain challenges to simultaneously meet high efficiency, large scale, low cost and high stability. Due to the low cost, extensive sources, high electrical conductivity and chemical stability, carbon materials have made undeniable contributions to play positive roles in developing PSCs. Carbon materials not only have the favorable conductivity but also bipolar advantage, which can transfer both electrons and holes. In this review, we will discuss how the carbon materials transfer charge or accelerate charge transport by incorporation in PSCs. Carbon materials can replace transparent conductive oxide layers, and enhance electron transport in electron transport layers. Moreover, carbon materials with continuous structure, especially carbon nanotubes and graphene, can provide direct charge transport channel that make them suitable additives or even substitutes in hole transport layers. Especially, the successful application of carbon materials as counter electrodes makes the devices full-printable, low temperature and high stability. Finally, a brief outlook is provided on the future development of carbon materials for PSCs, which are expected to devote more contributions in the future photovoltaic market.

  4. Fuel Cells for Portable Power: 1. Introduction to DMFCs; 2. Advanced Materials and Concepts for Portable Power Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Zelenay, Piotr [Los Alamos National Laboratory

    2012-07-16

    Thanks to generally less stringent cost constraints, portable power fuel cells, the direct methanol fuel cell (DMFC) in particular, promise earlier market penetration than higher power polymer electrolyte fuel cells (PEFCs) for the automotive and stationary applications. However, a large-scale commercialization of DMFC-based power systems beyond niche applications already targeted by developers will depend on improvements to fuel cell performance and performance durability as well as on the reduction in cost, especially of the portable systems on the higher end of the power spectrum (100-250 W). In this part of the webinar, we will focus on the development of advanced materials (catalysts, membranes, electrode structures, and membrane electrode assemblies) and fuel cell operating concepts capable of fulfilling two key targets for portable power systems: the system cost of $5/W and overall fuel conversion efficiency of 2.0-2.5 kWh/L. Presented research will concentrate on the development of new methanol oxidation catalysts, hydrocarbon membranes with reduced methanol crossover, and improvements to component durability. Time permitted, we will also present a few highlights from the development of electrocatalysts for the oxidation of two alternative fuels for the direct-feed fuel cells: ethanol and dimethyl ether.

  5. Review of New Technology for Preparing Crystalline Silicon Solar Cell Materials by Metallurgical Method

    Science.gov (United States)

    Li, Man; Dai, Yongnian; Ma, Wenhui; Yang, Bin; Chu, Qingmei

    2017-11-01

    The goals of greatly reducing the photovoltaic power cost and making it less than that of thermal power to realize photovoltaic power grid parity without state subsidies are focused on in this paper. The research status, key technologies and development of the new technology for preparing crystalline silicon solar cell materials by metallurgical method at home and abroad are reviewed. The important effects of impurities and defects in crystalline silicon on its properties are analysed. The importance of new technology on reducing production costs and improving its quality to increase the cell conversion efficiency are emphasized. The previous research results show that the raw materials of crystalline silicon are extremely abundant. The product of crystalline silicon can meet the quality requirements of solar cell materials: Si ≥ 6 N, P 1 Ω cm, minority carrier life > 25 μs cell conversion efficiency of about 19.3%, the product costs dollars / kg, the product energy consumption < 30 kwh / kg. The existing problems are pointed out. The prospect of the new metallurgical process with low cost, low energy consumption, low carbon and sustainable development are prospected.

  6. Cellular Responses in Human Dental Pulp Stem Cells Treated with Three Endodontic Materials

    Directory of Open Access Journals (Sweden)

    Alejandro Victoria-Escandell

    2017-01-01

    Full Text Available Human dental pulp stem cells (HDPSCs are of special relevance in future regenerative dental therapies. Characterizing cytotoxicity and genotoxicity produced by endodontic materials is required to evaluate the potential for regeneration of injured tissues in future strategies combining regenerative and root canal therapies. This study explores the cytotoxicity and genotoxicity mediated by oxidative stress of three endodontic materials that are widely used on HDPSCs: a mineral trioxide aggregate (MTA-Angelus white, an epoxy resin sealant (AH-Plus cement, and an MTA-based cement sealer (MTA-Fillapex. Cell viability and cell death rate were assessed by flow cytometry. Oxidative stress was measured by OxyBlot. Levels of antioxidant enzymes were evaluated by Western blot. Genotoxicity was studied by quantifying the expression levels of DNA damage sensors such as ATM and RAD53 genes and DNA damage repair sensors such as RAD51 and PARP-1. Results indicate that AH-Plus increased apoptosis, oxidative stress, and genotoxicity markers in HDPSCs. MTA-Fillapex was the most cytotoxic oxidative stress inductor and genotoxic material for HDPSCs at longer times in preincubated cell culture medium, and MTA-Angelus was less cytotoxic and genotoxic than AH-Plus and MTA-Fillapex at all times assayed.

  7. Analysis of Catalytic Material Effect on the Photovoltaic Properties of Monolithic Dye-sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Natalita Maulani Nursam

    2017-12-01

    Full Text Available Dye-sensitized solar cells (DSSC are widely developed due to their attractive appearance and simple fabrication processes. One of the challenges that arise in the DSSC fabrication involves high material cost associated with the cost of conductive substrate. DSSC with monolithic configuration was then developed on the basis of this motivation. In this contribution, titanium dioxide-based monolithic type DSSCs were fabricated on a single fluorine-doped transparent oxide coated glass using porous ZrO2 as spacer. Herein, the catalytic material for the counter-electrode was varied using carbon composite and platinum in order to analyze their effect on the solar cell efficiency. Four-point probe measurement revealed that the carbon composite exhibited slightly higher conductivity with a sheet resistance of 9.8 Ω/sq and 10.9 Ω/sq for carbon and platinum, respectively. Likewise, the photoconversion efficiency of the monolithic cells with carbon counter-electrode almost doubled the efficiency of the cells with platinum counter-electrode. Our results demonstrate that carbon could outperform the performance of platinum as catalytic material in monolithic DSSC.

  8. 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

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

    International Nuclear Information System (INIS)

    Shikama, Tatsuo

    1999-01-01

    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)

  10. Active matter at the interface between materials science and cell biology

    Science.gov (United States)

    Needleman, Daniel; Dogic, Zvonimir

    2017-09-01

    The remarkable processes that characterize living organisms, such as motility, self-healing and reproduction, are fuelled by a continuous injection of energy at the microscale. The field of active matter focuses on understanding how the collective behaviours of internally driven components can give rise to these biological phenomena, while also striving to produce synthetic materials composed of active energy-consuming components. The synergistic approach of studying active matter in both living cells and reconstituted systems assembled from biochemical building blocks has the potential to transform our understanding of both cell biology and materials science. This methodology can provide insight into the fundamental principles that govern the dynamical behaviours of self-organizing subcellular structures, and can lead to the design of artificial materials and machines that operate away from equilibrium and can thus attain life-like properties. In this Review, we focus on active materials made of cytoskeletal components, highlighting the role of active stresses and how they drive self-organization of both cellular structures and macroscale materials, which are machines powered by nanomachines.

  11. Chemical synthesis of Cd-free wide band gap materials for solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Sankapal, B.R.; Sartale, S.D.; Ennaoui, A. [Hahn-Meitner-Institut, Berlin (Germany). Department of Solar Energy Research; Lokhande, C.D. [Shivaji University, Kolhapur (India). Department of Physics

    2004-07-01

    Chemical methods are nowadays very attractive, since they are relatively simple, low cost and convenient for larger area deposition of thin films. In this paper, we outline our work related to the synthesis and characterization of some wide band gap semiconducting material thin films prepared by using solution methods, namely, chemical bath deposition and successive ionic layer adsorption and reaction (SILAR). The optimum preparative parameters are given and respective structural, surface morphological, compositional, optical, and electrical properties are described. Some materials we used in solar cells as buffer layers and achieved remarkable results, which are summarized. (author)

  12. Photosensitive self-assembling materials as functional dopants for organic photovoltaic cells

    Czech Academy of Sciences Publication Activity Database

    Bubnov, Alexej; Iwan, A.; Cigl, Martin; Boharewicz, B.; Tazbir, I.; Wójcik, K.; Sikora, A.; Hamplová, Věra

    2016-01-01

    Roč. 6, č. 14 (2016), s. 11577-11590 ISSN 2046-2069 R&D Projects: GA MŠk 7AMB13PL041; GA MŠk(CZ) LD14007; GA ČR GA15-02843S Grant - others:EU - ICT(XE) COST Action IC1208 Institutional support: RVO:68378271 Keywords : self-assembling materials * functional dopants * organic photovoltaic cells * azo group * liquid crystal Subject RIV: JI - Composite Materials Impact factor: 3.108, year: 2016

  13. 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.

  14. Modeling, Growth and Characterization of III-V and Dilute Nitride Antimonide Materials and Solar Cells

    Science.gov (United States)

    Maros, Aymeric

    III-V multijunction solar cells have demonstrated record efficiencies with the best device currently at 46 % under concentration. Dilute nitride materials such as GaInNAsSb have been identified as a prime choice for the development of high efficiency, monolithic and lattice-matched multijunction solar cells as they can be lattice-matched to both GaAs and Ge substrates. These types of cells have demonstrated efficiencies of 44% for terrestrial concentrators, and with their upright configuration, they are a direct drop-in product for today's space and concentrator solar panels. The work presented in this dissertation has focused on the development of relatively novel dilute nitride antimonide (GaNAsSb) materials and solar cells using plasma-assisted molecular beam epitaxy, along with the modeling and characterization of single- and multijunction solar cells. Nitrogen-free ternary compounds such as GaInAs and GaAsSb were investigated first in order to understand their structural and optical properties prior to introducing nitrogen. The formation of extended defects and the resulting strain relaxation in these lattice-mismatched materials is investigated through extensive structural characterization. Temperature- and power-dependent photoluminescence revealed an inhomogeneous distribution of Sb in GaAsSb films, leading to carrier localization effects at low temperatures. Tuning of the growth parameters was shown to suppress these Sb-induced localized states. The introduction of nitrogen was then considered and the growth process was optimized to obtain high quality GaNAsSb films lattice-matched to GaAs. Near 1-eV single-junction GaNAsSb solar cells were produced. The best devices used a p-n heterojunction configuration and demonstrated a current density of 20.8 mA/cm2, a fill factor of 64 % and an open-circuit voltage of 0.39 V, corresponding to a bandgap-voltage offset of 0.57 V, comparable with the state-of-the-art for this type of solar cells. Post-growth annealing

  15. Microfabrication of Si and GaAs by Plasma Etching Process Using Bacterial Cells as an Etching Mask Material

    Science.gov (United States)

    Matsutani, Akihiro; Takada, Ayako

    2012-08-01

    We demonstrated that bacterial cells can be used as a mask material for microfabrication of GaAs and Si by a Cl2 inductively coupled plasma (ICP) etching process. The etching rate of Escherichia coli cells was similar to that of electron beam resist or nanoimprint resist. We also demonstrated the degradation of bacterial cells by low-pressure plasma treatment using O2, Ar, air, and H2O for removal of bacterial cells as the etching mask material. Bacterial cells were efficiently degraded by ions in the low-pressure discharge plasma. The proposed process using bacterial cells can be expected to be applied to semiconductor dry etching processes.

  16. Synthetic clay as an alternative backing material for passive temperature control of photovoltaic cells

    International Nuclear Information System (INIS)

    Alami, Abdul Hai

    2016-01-01

    This paper evaluates the operational advantages of using a backing material for photovoltaic modules different than the industry-standard Tedlar. Synthetic clay, composed mostly of gypsum, is investigated to be part of cells backing and has been found to provide passive cooling properties, successfully reducing the operating temperatures of tested cells from 28 °C to 10 °C. The XRD (X-Ray diffraction) and SEM (Scanning Electron Microscopy) microstructural examination, as well as porosity tests have revealed the random pore distribution of the clay and their volumetric stability at high operating temperatures, which is essential in enhancing evaporation. The characterization of IV performance of bare cells compared with ones backed by clay and aluminum revealed the structural and thermal advantages of using clay, while Nyquist plots revealed the independence of cell impedance from the mist of cooling water provided to clay medium, adding an extra 34.6% of power output when the former is compared to reference cells. - Highlights: • Characterizing clay as a porous media for evaporative cooling. • Microstructural (SEM and XRD) of the clay material. • Enhancing the efficiency and power of PV modules.

  17. Soliciting strategies for developing cell-based reference materials to advance mesenchymal stromal cell research and clinical translation.

    Science.gov (United States)

    Viswanathan, Sowmya; Keating, Armand; Deans, Robert; Hematti, Peiman; Prockop, Darwin; Stroncek, David F; Stacey, Glyn; Weiss, Dan J; Mason, Christopher; Rao, Mahendra S

    2014-06-01

    The mesenchymal stromal cell (MSC) field continues to rapidly progress with a number of clinical trials initiated and completed, with some reported successes in multiple clinical indications, and a growing number of companies established. The field, nevertheless, faces several challenges. Persistent issues include the definition of a MSC and comparability between MSC preparations. This is because of inherent cell heterogeneity, the absence of markers that are unique to MSCs, and the difficulty in precisely defining them by developmental origin. Differences in the properties of MSCs also depend on the site of tissue harvest, phenotypic and genotypic characteristics of the donor and the isolation, and storage and expansion methods used. These differences may be sufficient to ensure that attributes of the final MSC product could differ in potentially significant ways. Since there are currently no gold standards, we propose using a reference material to establish methods of comparability among MSC preparations. We suggest four possible "ruler scenarios" and a method for global distribution. We further suggest that critical to establishing a reference material is the need to define protocols for comparing cells. The main purpose of this article is to solicit input in establishing a consensus-based comparison. A comparative approach will be critical to all stages of translation to better clarify mechanisms of MSC actions, define an optimal cell manufacturing process, ensure best practice clinical investigations, extend the use of an MSC product for new indications, protect an MSC product from imitators, and develop uniform reimbursement policies. Importantly, a reference material may enable a consensus on a practical definition of MSCs.

  18. 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.

  19. 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.

  20. Cross-reacting material 197 (CRM197) affects actin cytoskeleton of endothelial cells.

    Science.gov (United States)

    Özerman Edis, Bilge; Varol, Başak; Hacıosmanoğlu, Ebru; Ünlü, Ayhan; Bektaş, Muhammet

    2017-10-01

    CRM197, cross-reacting material 197, is a mutant of diphtheria toxin (DTx). CRM197 is used in pharmacology as a carrier protein. It has been recently shown that CRM197 causes breakdown in actin filaments. In order to show intracellular localization of CRM197 and visualize cell structure via actin cytoskeleton, endothelial cells were cultured and subjected to CRM197 in vitro. To address the interaction between CRM197 and actin both experimental and theoretical studies were carried out. Colocalization of CRM197 with actin filaments was determined by immunofluorescence microscopy. Following 24-hour incubation, the loss of cell-cell contact between cells was prominent. CRM197 was shown to bind to G-actin by gel filtration chromatography, and this binding was confirmed by Western blot analysis of eluted samples obtained following chromatography. Based on crystal structure, docked model of CRM197-actin complex was generated. Molecular dynamics simulation revealed that Lys42, Cys218, Cys233 of CRM197 interacts with Gly197, Arg62 and Ser60 of G-actin, respectively. CRM197 binding to G-actin, colocalization of CRM197 with actin filament, and actin cytoskeleton rearrangement resulting in the loss of cell-cell contact show that actin comes into sight as target molecule for CRM197.

  1. 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.

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

    Science.gov (United States)

    Badawy, Waheed A

    2015-03-01

    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. 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.

  3. Renewable and functional wood materials by grafting polymerization within cell walls.

    Science.gov (United States)

    Cabane, Etienne; Keplinger, Tobias; Merk, Vivian; Hass, Philipp; Burgert, Ingo

    2014-04-01

    A "grafting-from" polymerization approach within and at the complex and heterogeneous macromolecular assembly of wood cell walls is shown. The approach allows for the implementation of novel functionalities in renewable and functional wood-based materials. The native wood structure is retained and used as a hierarchical multiscale framework for a modular two-step polymerization process. The versatility and potential of the approach is shown by a polymerization of either hydrophobic or hydrophilic and pH-responsive monomers in the wood structure. Characterization of the modified wood reveals the presence of polymer in the cell wall, and the new properties of these wood materials are discussed. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Development of maintenance equipment for nuclear material fabrication equipment in a highly active hot cell

    Energy Technology Data Exchange (ETDEWEB)

    Park, J. J.; Yang, M. S.; Kim, K. H. and others

    2000-09-01

    This report presents the development of a maintenance system for a highly contaminated nuclear material handling equipment at a hot-cell. This maintenance system has mainly three subsystems - a gamma-radiation measurement module for detecting a gamma-radiation level and identifying its distribution in-situ, a dry-type decontamination device for cleaning up contaminated particles, and a maintenance chamber for isolating contaminated equipment. The mechanical design considerations, controller, capabilities and remote operation and manipulation of the maintenance system are described. Such subsystems developed were installed and tested in the IMEF (Irradiated Material Examination Facility) M6 hot-cell after mock-up tests and performed their specific tasks successfully.

  5. Development of maintenance equipment for nuclear material fabrication equipment in a highly active hot cell

    International Nuclear Information System (INIS)

    Park, J. J.; Yang, M. S.; Kim, K. H. and others

    2000-09-01

    This report presents the development of a maintenance system for a highly contaminated nuclear material handling equipment at a hot-cell. This maintenance system has mainly three subsystems - a gamma-radiation measurement module for detecting a gamma-radiation level and identifying its distribution in-situ, a dry-type decontamination device for cleaning up contaminated particles, and a maintenance chamber for isolating contaminated equipment. The mechanical design considerations, controller, capabilities and remote operation and manipulation of the maintenance system are described. Such subsystems developed were installed and tested in the IMEF (Irradiated Material Examination Facility) M6 hot-cell after mock-up tests and performed their specific tasks successfully

  6. 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.

  7. Strategies for Carbon and Sulfur Tolerant Solid Oxide Fuel Cell Materials, Incorporating Lessons from Heterogeneous Catalysis.

    Science.gov (United States)

    Boldrin, Paul; Ruiz-Trejo, Enrique; Mermelstein, Joshua; Bermúdez Menéndez, José Miguel; Ramı Rez Reina, Tomás; Brandon, Nigel P

    2016-11-23

    Solid oxide fuel cells (SOFCs) are a rapidly emerging energy technology for a low carbon world, providing high efficiency, potential to use carbonaceous fuels, and compatibility with carbon capture and storage. However, current state-of-the-art materials have low tolerance to sulfur, a common contaminant of many fuels, and are vulnerable to deactivation due to carbon deposition when using carbon-containing compounds. In this review, we first study the theoretical basis behind carbon and sulfur poisoning, before examining the strategies toward carbon and sulfur tolerance used so far in the SOFC literature. We then study the more extensive relevant heterogeneous catalysis literature for strategies and materials which could be incorporated into carbon and sulfur tolerant fuel cells.

  8. Determination and interpretation of the optical constants for solar cell materials

    Science.gov (United States)

    Fujiwara, Hiroyuki; Fujimoto, Shohei; Tamakoshi, Masato; Kato, Masato; Kadowaki, Hideyuki; Miyadera, Tetsuhiko; Tampo, Hitoshi; Chikamatsu, Masayuki; Shibata, Hajime

    2017-11-01

    Solar cell materials in thin film form often exhibit quite rough surface, which makes the accurate determination of the optical constants using spectroscopic ellipsometry (SE) quite difficult. In this study, we investigate the effect of the rough surface on the SE analysis and establish an analysis procedure, which is quite helpful for the correction of the underestimated roughness contribution. As examples, the roughness analyses for CuInSe2 and CH3NH3PbI3 hybrid-perovskite thin films are presented. Moreover, to interpret the dielectric functions of emerging solar cell materials, such as CH3NH3PbI3 and Cu2ZnSnSe4, the optical transition analyses are performed based on density functional theory (DFT). The excellent agreement observed between the experimental and DFT results allows the detailed assignment of the transition peaks, confirming the importance of DFT for revealing fundamental optical characteristics.

  9. 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.

  10. Yielding and post-yield behaviour of closed-cell cellular materials under multiaxial dynamic loading

    Science.gov (United States)

    Vesenjak, Matej; Ren, Zoran

    2016-05-01

    The paper focuses on characterisation of yielding and post-yield behaviour of metals with closed-cell cellular structure when subjected to multiaxial dynamic loading, considering the influence of the relative density, base material, strain rate and pore gas pressure. Research was conducted by extensive parametric fully-coupled computational simulations using the finite element code LS-DYNA. Results have shown that the macroscopic yield stress of cellular material rises with increase of the relative density, while its dependence on the hydrostatic stress decreases. The yield limit also rises with increase of the strain rate, while the hydrostatic stress influence remains more or less the same at different strain-rates. The macroscopic yield limit of the cellular material is also strongly influenced by the choice of base material since the base materials with higher yield limit contribute also to higher macroscopic yield limit of the cellular material. By increasing the pore gas filler pressure the dependence on hydrostatic stress increases while at the same time the yield surface shifts along the hydrostatic axis in the negative direction. This means that yielding at compression is delayed due to influence of the initial pore pressure and occurs at higher compressive loading, while the opposite is true for tensile 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.

    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)

  12. 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)

  13. 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.'

  14. Strategies for carbon and sulfur tolerant solid oxide fuel cell materials, incorporating lessons from heterogeneous catalysis

    OpenAIRE

    Boldrin, P; Ruiz Trejo, E; Mermelstein, J; Bermudez Menendez, J; Ramirez Reina, T; Brandon, N

    2016-01-01

    Solid oxide fuel cells (SOFCs) are a rapidly emerging energy technology for a low carbon world, providing high efficiency, potential to use carbonaceous fuels and compatibility with carbon capture and storage. However, current state-of-the-art materials have low tolerance to sulfur, a common contaminant of many fuels, and are vulnerable to deactivation due to carbon deposition when using carbon-containing compounds. In this review we first study the theoretical basis behind carbon and sulfur ...

  15. 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

  16. Nanostructured material-based biofuel cells: recent advances and future prospects.

    Science.gov (United States)

    Zhao, Cui-E; Gai, Panpan; Song, Rongbin; Chen, Ying; Zhang, Jianrong; Zhu, Jun-Jie

    2017-03-06

    During the past decade, biofuel cells (BFCs) have emerged as an emerging technology on account of their ability to directly generate electricity from biologically renewable catalysts and fuels. Due to the boost in nanotechnology, significant advances have been accomplished in BFCs. Although it is still challenging to promote the performance of BFCs, adopting nanostructured materials for BFC construction has been extensively proposed as an effective and promising strategy to achieve high energy production. In this review, we presented the major novel nanostructured materials applied for BFCs and highlighted the breakthroughs in this field. Based on different natures of the bio-catalysts and electron transfer process at the bio-electrode surfaces, the fundamentals of BFC systems, including enzymatic biofuel cells (EBFCs) and microbial fuel cells (MFCs), have been elucidated. In particular, the principle of electrode materials design has been detailed in terms of enhancing electrical communications between biological catalysts and electrodes. Furthermore, we have provided the applications of BFCs and potential challenges of this technology.

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

    Directory of Open Access Journals (Sweden)

    Afaf M. Abd El-Hameed

    2015-12-01

    Full Text Available 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.

  18. New innovative materials for advanced electrochemical applications in battery and fuel cell systems

    Science.gov (United States)

    Voß, S.; Kollmann, H.; Kollmann, W.

    The advanced material POLYMET is an innovative high tech polymer with a three-dimensional polymeric structure metallized with an enclosing coating of different kinds of metals or alloys. The result is a range of tailor-made, microporous structures on a designable scale. By varying the metals and alloys, it is possible to draw upon extremely diverse areas of applications such as battery systems, fuel cells, filters or efficient catalysts as well as air regeneration systems, e.g. in aerospace. The three-dimensional structure of metallized high tech woven or non-woven materials or foams causes a lot of advantages such as high conductivity, high corrosion resistance, flexibility or mechanical strength. Therefore, POLYMET is suitable for, e.g. current collectors or gas diffusion layers in energy storage systems. They supply an economic and environmental alternative material to improve functional electrochemical systems.

  19. Proton exchange membrane materials for the advancement of direct methanol fuel-cell technology

    Science.gov (United States)

    Cornelius, Christopher J [Albuquerque, NM

    2006-04-04

    A new class of hybrid organic-inorganic materials, and methods of synthesis, that can be used as a proton exchange membrane in a direct methanol fuel cell. In contrast with Nafion.RTM. PEM materials, which have random sulfonation, the new class of materials have ordered sulfonation achieved through self-assembly of alternating polyimide segments of different molecular weights comprising, for example, highly sulfonated hydrophilic PDA-DASA polyimide segment alternating with an unsulfonated hydrophobic 6FDA-DAS polyimide segment. An inorganic phase, e.g., 0.5 5 wt % TEOS, can be incorporated in the sulfonated polyimide copolymer to further improve its properties. The new materials exhibit reduced swelling when exposed to water, increased thermal stability, and decreased O.sub.2 and H.sub.2 gas permeability, while retaining proton conductivities similar to Nafion.RTM.. These improved properties may allow direct methanol fuel cells to operate at higher temperatures and with higher efficiencies due to reduced methanol crossover.

  20. Cytology smears as diagnostic material for EGFR gene testing in non-small cell lung cancer.

    Science.gov (United States)

    Powrózek, Tomasz; Krawczyk, Paweł; Pankowski, Juliusz; Reszka, Katarzyna; Jakubiak, Magdalena; Obrochta, Anna; Wojas-Krawczyk, Kamila; Buczkowski, Jarosław; Milanowski, Janusz

    2015-11-14

    Cytology smears can be effectively used for EGFR mutation testing in the qualification of NSCLC patients for EGFR tyrosine kinase inhibitor therapy. However, tissue specimens are preferred for EGFR mutation analysis. The aim of this study was to estimate the effectiveness of the real-time PCR method for EGFR testing in histology and cytology materials obtained simultaneously from NSCLC patients. Fourteen adenocarcinoma patients with EGFR-mutation-positive primary tumor tissues were included in the study. Corresponding cytological smears of metastatic lymph nodes obtained by EBUS-TBNA were examined. EGFR Mutation Analysis Kit (EntroGen, USA) and real-time PCR (m2000rt system, Abbott, USA) were used for EGFR mutation analysis in both types of material. In primary tumor tissues, 12 deletions in exon 19 and 2 substitutions in exon 21 (L858R mutation) of the EGFR gene were found. Except for 1 deletion in exon 19, the same EGFR gene mutations were detected in all corresponding cytology samples. The percentage of tumor cells, DNA concentration, percentage of mutated DNA as well as ΔCt values were similar in cytology slides and histology material. In both types of materials, no significant correlations were found between the percentage of tumor cells and the percentage of mutated DNA nor between the DNA concentration and the percentage of mutated DNA. We demonstrated the high effectiveness of a sensitive real-time PCR method in EGFR gene mutation detection in cytology smears.

  1. Eksplorasi dan Karakterisasi Tanaman Genjer (Limnocharis flava (L. Buch di Kabupaten Pangandaran Berdasarkan Karakter Morfologi dan Agronomi

    Directory of Open Access Journals (Sweden)

    Liberty Chaidir

    2016-12-01

    Full Text Available Genjer merupakan tanaman yang tumbuh liar di area persawahan, rawa, atau sungai yang keberadaannya sering dianggap sebagai gulma. Tanaman genjer memiliki banyak manfaat, diantaranya sebagai bahan penyerap logam berat dalam tanah dan sebagai obat yang memiliki banyak kandungan gizi. Penelitian ini bertujuan untuk mengetahui variasi karakter morfologi dan karakter agronomi untuk mengetahui hubungan kekerabatan tanaman genjer antar daerah di Kabupaten Pangandaran. Penelitian dilaksanakan di Kabupaten Pangandaran pada Mei sampai Oktober 2015. Metode yang digunakan adalah metode eksplorasi purposive sampling pada 77 aksesi genjer yang diambil dari Kabupaten Pangandaran. Hasil penelitian menunjukkan terdapat keragaman fenotipik yang luas pada karakter morfologi ujung daun, warna batang, tekstur daun, warna daun, panjang lekukan bawah daun, warna kelopak bunga dan warna bunga. Karakter agronomi yang mempunyai keragaman yang luas ialah tinggi tanaman, jumlah batang per rumpun, panjang daun, lebar daun, jumlah daun, jumlah bunga dan diameter batang. Tanaman genjer di Kabupaten Pangandaran memiliki kekerabatan yang jauh dengan rentang jarak Euclidian 0,48 sampai 10,17. Aksesi yang memiliki hubungan kekerabatan paling jauh yaitu Ciakar (001 dengan jarak Euclidian 10,17, sedangkan yang memiliki hubungan kekerabatan paling dekat yaitu Cikalong (003 dan Cikalong (004 dengan jarak Euclidian 0,48. Genjer or Yellow velvetleaf is a plant that grows wild in lowland area, swamp or river which existence is considered as a weed. Genjer has a lot of benefits, such as material absorbent for heavy metals in the soil and medicine that has a lot of nutrition. This study aimed to determine the variety of morphological and agronomic characters of Genjer in Pangandaran Regency and to determine the genetic relationship of genjer between regions in Pangandaran. The research was conducted in the Pangandaran Regency on May to October 2015. The method used purposive sampling

  2. Emerging Prototype Sodium-Ion Full Cells with Nanostructured Electrode Materials.

    Science.gov (United States)

    Ren, Wenhao; Zhu, Zixuan; An, Qinyou; Mai, Liqiang

    2017-06-01

    Due to steadily increasing energy consumption, the demand of renewable energy sources is more urgent than ever. Sodium-ion batteries (SIBs) have emerged as a cost-effective alternative because of the earth abundance of Na resources and their competitive electrochemical behaviors. Before practical application, it is essential to establish a bridge between the sodium half-cell and the commercial battery from a full cell perspective. An overview of the major challenges, most recent advances, and outlooks of non-aqueous and aqueous sodium-ion full cells (SIFCs) is presented. Considering the intimate relationship between SIFCs and electrode materials, including structure, composition and mutual matching principle, both the advance of various prototype SIFCs and the electrochemistry development of nanostructured electrode materials are reviewed. It is noted that a series of SIFCs combined with layered oxides and hard carbon are capable of providing a high specific gravimetric energy above 200 Wh kg -1 , and an NaCrO 2 //hard carbon full cell is able to deliver a high rate capability over 100 C. To achieve industrialization of SIBs, more systematic work should focus on electrode construction, component compatibility, and battery technologies. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Controlled cadmium telluride thin films for solar cell applications (emerging materials systems for solar cell applications)

    Science.gov (United States)

    Vedam, K.; Das, M. B.; Krishnaswamy, S. V.

    1980-02-01

    Emphasis during the third quarter of the program was on the improvement of the quality of sputtered films, their characterization and use in the fabrication of Schottky barrier type diodes and solar cell structures. Films prepared under different conditions and on different substrates were examined showing modular growths under certain conditions. I-V, C-V, and photovoltaic characteristics were measured on numerous samples based on n- and p-type films on Ni substrates having top metallization of either evaporated Au and Al. The n-type samples showed up to 200 mV V/sub oc/and small short-circuit currents. The characteristics observed are indicative of the presence of interfacial layer and surface states. Surface state's capacitance were measured on p-type samples metalized with Au.

  4. Performance Maintenance of Dye-Sensitized Solar Cells Using a Latent Heat Storage Material

    Science.gov (United States)

    Haruki, Naoto; Horibe, Akihiko

    2017-07-01

    Recently, there has been considerable interest in various renewable energies. Among them, solar cell production has increased markedly because the photovoltaic is a clean and safe power generation method. The dye-sensitized solar cell (DSSC) has attracted much attention as an alternative to silicon solar cells due to lower manufacturing costs and plentiful resources for DSSC production. However, the performance of DSSCs has been limited by their durability and low photoelectric conversion efficiency. Temperature control of DSSCs via phase-change materials (PCMs) is expected to improve performance. In this study, DSSCs were heated or cooled with a heat exchanger copper block that was in contact with a PCM (heptadecane), while being irradiated by a solar simulator light source. The durability and photoelectric conversion efficiency of the DSSC improved under PCM temperature control.

  5. Characterization of mammalian cell culture raw materials by combining spectroscopy and chemometrics.

    Science.gov (United States)

    Trunfio, Nicholas; Lee, Haewoo; Starkey, Jason; Agarabi, Cyrus; Liu, Jay; Yoon, Seongkyu

    2017-07-01

    Two of the primary issues with characterizing the variability of raw materials used in mammalian cell culture, such as wheat hydrolysate, is that the analyses of these materials can be time consuming, and the results of the analyses are not straightforward to interpret. To solve these issues, spectroscopy can be combined with chemometrics to provide a quick, robust and easy to understand methodology for the characterization of raw materials; which will improve cell culture performance by providing an assessment of the impact that a given raw material will have on final product quality. In this study, four spectroscopic technologies: near infrared spectroscopy, middle infrared spectroscopy, Raman spectroscopy, and fluorescence spectroscopy were used in conjunction with principal component analysis to characterize the variability of wheat hydrolysates, and to provide evidence that the classification of good and bad lots of raw material is possible. Then, the same spectroscopic platforms are combined with partial least squares regressions to quantitatively predict two cell culture critical quality attributes (CQA): integrated viable cell density and IgG titer. The results showed that near infrared (NIR) spectroscopy and fluorescence spectroscopy are capable of characterizing the wheat hydrolysate's chemical structure, with NIR performing slightly better; and that they can be used to estimate the raw materials' impact on the CQAs. These results were justified by demonstrating that of all the components present in the wheat hydrolysates, six amino acids: arginine, glycine, phenylalanine, tyrosine, isoleucine and threonine; and five trace elements: copper, phosphorus, molybdenum, arsenic and aluminum, had a large, statistically significant effect on the CQAs, and that NIR and fluorescence spectroscopy performed the best for characterizing the important amino acids. It was also found that the trace elements of interest were not characterized well by any of the spectral

  6. Oxygen transport in perovskite-type solid oxide fuel cell materials: insights from quantum mechanics.

    Science.gov (United States)

    Muñoz-García, Ana B; Ritzmann, Andrew M; Pavone, Michele; Keith, John A; Carter, Emily A

    2014-11-18

    CONSPECTUS: Global advances in industrialization are precipitating increasingly rapid consumption of fossil fuel resources and heightened levels of atmospheric CO2. World sustainability requires viable sources of renewable energy and its efficient use. First-principles quantum mechanics (QM) studies can help guide developments in energy technologies by characterizing complex material properties and predicting reaction mechanisms at the atomic scale. QM can provide unbiased, qualitative guidelines for experimentally tailoring materials for energy applications. This Account primarily reviews our recent QM studies of electrode materials for solid oxide fuel cells (SOFCs), a promising technology for clean, efficient power generation. SOFCs presently must operate at very high temperatures to allow transport of oxygen ions and electrons through solid-state electrolytes and electrodes. High temperatures, however, engender slow startup times and accelerate material degradation. SOFC technologies need cathode and anode materials that function well at lower temperatures, which have been realized with mixed ion-electron conductor (MIEC) materials. Unfortunately, the complexity of MIECs has inhibited the rational tailoring of improved SOFC materials. Here, we gather theoretically obtained insights into oxygen ion conductivity in two classes of perovskite-type materials for SOFC applications: the conventional La1-xSrxMO3 family (M = Cr, Mn, Fe, Co) and the new, promising class of Sr2Fe2-xMoxO6 materials. Using density functional theory + U (DFT+U) with U-J values obtained from ab initio theory, we have characterized the accompanying electronic structures for the two processes that govern ionic diffusion in these materials: (i) oxygen vacancy formation and (ii) vacancy-mediated oxygen migration. We show how the corresponding macroscopic oxygen diffusion coefficient can be accurately obtained in terms of microscopic quantities calculated with first-principles QM. We find that the

  7. 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.

  8. 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.

  9. 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

  10. Frost induced damages within porous materials - from concrete technology to fuel cells technique

    Science.gov (United States)

    Palecki, Susanne; Gorelkov, Stanislav; Wartmann, Jens; Heinzel, Angelika

    2017-12-01

    Porous media like concrete or layers of membrane electrode assemblies (MEA) within fuel cells are affected by a cyclic frost exposure due to different damage mechanisms which could lead to essential degradation of the material. In general, frost damages can only occur in case of a specific material moisture content. In fuel cells, residual water is generally available after shut down inside the membrane i.e. the gas diffusion layer (GDL). During subsequent freezing, this could cause various damage phenomena such as frost heaves and delamination effects of the membrane electrode assembly, which depends on the location of pore water and on the pore structure itself. Porous materials possess a pore structure that could range over several orders of magnitudes with different properties and freezing behaviour of the pore water. Latter can be divided into macroscopic, structured and pre-structured water, influenced by surface interactions. Therefore below 0 °C different water modifications can coexist in a wide temperature range, so that during frost exposure a high amount of unfrozen and moveable water inside the pore system is still available. This induces transport mechanisms and shrinkage effects. The physical basics are similar for porous media. While the freezing behaviour of concrete has been studied over decades of years, in order to enhance the durability, the know-how about the influence of a frost attack on fuel cell systems is not fully understood to date. On the basis of frost damage models for concrete structures, an approach to describe the impact of cyclic freezing and thawing on membrane electrode assemblies has been developed within this research work. Major aim is beyond a better understanding of the frost induced mechanisms, the standardization of a suitable test procedure for the assessment of different MEA materials under such kind of attack. Within this contribution first results will be introduced.

  11. A large coaxial reflection cell for broadband dielectric characterization of coarse-grained materials

    Science.gov (United States)

    Bore, Thierry; Bhuyan, Habibullah; Bittner, Tilman; Murgan, Vignesh; Wagner, Norman; Scheuermann, Alexander

    2018-01-01

    Knowledge of the frequency-dependent electromagnetic properties of coarse-grained materials is imperative for the successful application of high frequency electromagnetic measurement techniques for near and subsurface monitoring. This paper reports the design, calibration and application of a novel one-port large coaxial cell for broadband complex permittivity measurements of civil engineering materials. It was designed to allow the characterization of heterogeneous material with large aggregate dimensions (up to 28 mm) over a frequency range from 1 MHz-860 MHz. In the first step, the system parameters were calibrated using the measured scattering function in a perfectly known dielectric material in an optimization scheme. In the second step, the method was validated with measurements made on standard liquids. Then the performance of the cell was evaluated on a compacted coarse-grained soil. The dielectric spectra were obtained by means of fitting the measured scattering function using a transverse electromagnetic mode propagation model considering the frequency-dependent complex permittivity. Two scenarios were systematically analyzed and compared. The first scenario consisted of a broadband generalized dielectric relaxation model with two Cole-Cole type relaxation processes related to the interaction of the aqueous phase and the solid phase, a constant high frequency contribution as well as an apparent direct current conductivity term. The second scenario relied on a three-phase theoretical mixture equation which was used in a forward approach in order to calibrate the model. Both scenarios provide almost identical results for the broadband effective complex relative permittivity. The combination of both scenarios suggests the simultaneous estimation of water content, density, bulk and pore water conductivity for road base materials for in situ applications.

  12. Characterization of mammalian cell culture raw materials by combining spectroscopy and chemometrics

    Science.gov (United States)

    Trunfio, Nicholas; Lee, Haewoo; Starkey, Jason; Agarabi, Cyrus; Liu, Jay

    2017-01-01

    Two of the primary issues with characterizing the variability of raw materials used in mammalian cell culture, such as wheat hydrolysate, is that the analyses of these materials can be time consuming, and the results of the analyses are not straightforward to interpret. To solve these issues, spectroscopy can be combined with chemometrics to provide a quick, robust and easy to understand methodology for the characterization of raw materials; which will improve cell culture performance by providing an assessment of the impact that a given raw material will have on final product quality. In this study, four spectroscopic technologies: near infrared spectroscopy, middle infrared spectroscopy, Raman spectroscopy, and fluorescence spectroscopy were used in conjunction with principal component analysis to characterize the variability of wheat hydrolysates, and to provide evidence that the classification of good and bad lots of raw material is possible. Then, the same spectroscopic platforms are combined with partial least squares regressions to quantitatively predict two cell culture critical quality attributes (CQA): integrated viable cell density and IgG titer. The results showed that near infrared (NIR) spectroscopy and fluorescence spectroscopy are capable of characterizing the wheat hydrolysate's chemical structure, with NIR performing slightly better; and that they can be used to estimate the raw materials’ impact on the CQAs. These results were justified by demonstrating that of all the components present in the wheat hydrolysates, six amino acids: arginine, glycine, phenylalanine, tyrosine, isoleucine and threonine; and five trace elements: copper, phosphorus, molybdenum, arsenic and aluminum, had a large, statistically significant effect on the CQAs, and that NIR and fluorescence spectroscopy performed the best for characterizing the important amino acids. It was also found that the trace elements of interest were not characterized well by any of the spectral

  13. Material synthesis and fabrication method development for intermediate temperature solid oxide fuel cells

    Science.gov (United States)

    Ding, Hanping

    Solid oxide fuel cells (SOFCs) are operated in high temperature conditions (750-1000 °C). The high operating temperature in turn may lead to very complicated material degradation issues, significantly increasing the cost and reducing the durability of SOFC material systems. In order to widen material selections, reduce cost, and increase durability of SOFCs, there is a growing interest to develop intermediate temperature SOFCs (500-750 °C). However, lowering operating temperature will cause substantial increases of ohmic resistance of electrolyte and polarization resistance of electrodes. This dissertation aimed at developing high-performance intermediate-temperature SOFCs through the employment of a series of layered perovskite oxides as novel cathode materials to minimize the potential electrode polarization on oxygen reduction reaction resulting from the unique crystal structure. The high performance of such perovskites under lower temperatures lies in the fact that a simple cubic perovskite with randomly occupied A-sites transforming into a layered compound with ordered lanthanide and alkali-earth cations may reduce the oxygen bonding strength and provide disorder-free channels for oxygen ion migrations. In order to compromise the cell performance and chemical and mechanical stability, the substitution of Fe in B site was comprehensively investigated to explore the effects of Fe doping on the crystal structure, thermal and electrical properties, as well as electrochemical performance. Furthermore, a platinum nanowire network was successfully developed as an ultrathin electrochemically efficient current collector for SOFCs. The unique platinum network on cathode surface can connect the oxygen reduction reaction (ORR) sites at the nano-scale to the external circuit while being able to substantially avoid blocking the open pores of the cathode. The superior electrochemical performance was exhibited, including the highly reduced electrode polarization resistance

  14. Innovative anode materials and architectured cells for high temperature steam electrolysis operation

    International Nuclear Information System (INIS)

    Ogier, Tiphaine

    2012-01-01

    In order to improve the electrochemical performances of cells for high temperature steam electrolysis (HTSE), innovative oxygen electrode materials have been studied. The compounds Ln 2 NiO 4+δ (Ln = La, Pr or Nd), Pr 4 Ni 3 O 10±δ and La 0,6 S r 0 ,4 Fe 0,8 Co 0,2 O 3-δ have been selected for their mixed electronic and ionic conductivity. First, their physical and chemical properties have been investigated. Then, the electrodes were shaped on symmetrical half cells,adding a thin ceria-based interlayer between the electrode and the yttria doped zirconia-based electrolyte. These architectured cells lead to low polarization resistances (RP≤ 0.1 Ω.cm 2 at 800 C) as well as reduced anodic over potentials. An electrochemical model has been developed in order to describe and analyze the experimental polarization curves.The electrode with the lower overpotential, i.e. Pr 2 NiO 4+ δ, has been selected and characterized into complete cermet-supported cells. Under HTSE operation, at 800 C, a high current density was measured, close to i = -0.9 A.cm -2 for a cell voltage equals to 1.3 V, the conversion rate being about 60%. (author) [fr

  15. Exploratory Testing of Diatom Silica to Map the Role of Material Attributes on Cell Fate.

    Science.gov (United States)

    Walsh, Pamela J; Clarke, Susan A; Julius, Matthew; Messersmith, Phillip B

    2017-10-26

    Porous silica is an attractive biomaterial in many applications, including drug-delivery systems, bone-graft fillers and medical devices. The issue with porous silica biomaterials is the rate at which they resorb and the significant role played by interfacial chemistry on the host response in vivo. This paper explores the potential of diatom-biosilica as a model tool to assist in the task of mapping and quantifying the role of surface topography and chemical cues on cell fate. Diatoms are unicellular microalgae whose cell walls are composed of, amorphous nanopatterned biosilica that cannot be replicated synthetically. Their unique nanotopography has the potential to improve understanding of interface reactions between materials and cells. This study used Cyclotella meneghiniana as a test subject to assess cytotoxicity and pro-inflammatory reactions to diatom-biosilica. The results suggest that diatom-biosilica is non-cytotoxic to J774.2 macrophage cells, and supports cell proliferation and growth. The addition of amine and thiol linkers have shown a significant effect on cytotoxicity, growth and cytokine response, thus warranting further investigation into the interfacial effects of small chemical modifications to substrate surfaces. The overall findings suggest diatom-biosilica offers a unique platform for in-depth investigation of the role played by nanotopography and chemistry in biomedical applications.

  16. Evaluation of cytotoxicity and gelatinases activity in 3T3 fibroblast cell by root repair materials

    Directory of Open Access Journals (Sweden)

    Varol Basak

    2016-09-01

    Full Text Available The aim of this study was to investigate the effects of calcium silicate-based products on cytotoxicity in the 3T3 fibroblast and gelatinolytic activity of matrix metalloproteinases (MMPs. 3T3 fibroblasts were incubated directly with Ortho Mineral trioxide aggregate (MTA, BioAggregate, Biodentine, MTA Plus, MTA Angelus and MTA Cerkamed for 24 hours and seven days. The cytotoxicity was determined using an MTT assay. Supernatants were collected to determine MMP-2 and MMP-9. Data were analysed using IBM SPSS 22. Seventh day extracts of Ortho MTA and Biodentine showed reduced cell viability. Specific characterization of MMPs in cell culture demonstrated that MMP-2 (62 kPa in the cell culture supernatants by gelatin zymography showed induced expression in four out of seven groups by 3T3 cells. No MMP-9 expression was observed. The cytotoxicity of materials revealed a significant difference in cell viability between the groups on the first and seventh days. The results of this study revealed minor cytotoxic effects for Ortho MTA and Biodentine. This study suggests that endodontic sealers induced production of MMP-2. MMP-9 might be expressed in small amounts when compared with MMP-2.

  17. High Energy Density Li-ion Cells for EV’s Based on Novel, High Voltage Cathode Material Systems

    Energy Technology Data Exchange (ETDEWEB)

    Kepler, Keith [Farasis Energy Inc; Slater, Michael [Farasis Energy Inc

    2018-03-14

    This Li-ion cell technology development project had three objectives: to develop advanced electrode materials and cell components to enable stable high-voltage operation; to design and demonstrate a Li-ion cell using these materials that meets the PHEV40 performance targets; and to design and demonstrate a Li-ion cell using these materials that meets the EV performance targets. The major challenge to creating stable high energy cells with long cycle life is system integration. Although materials that can give high energy cells are known, stabilizing them towards long-term cycling in the presence of other novel cell components is a major challenge. The major technical barriers addressed by this work include low cathode specific energy, poor electrolyte stability during high voltage operation, and insufficient capacity retention during deep discharge for Si-containing anodes. Through the course of this project, Farasis was able to improve capacity retention of NCM materials for 4.4+ V operation, through both surface treatment and bulk-doping approaches. Other material advances include increased rate capability and of HE-NCM materials through novel synthesis approach, doubling the relative capacity at 1C over materials synthesized using standard methods. Silicon active materials proved challenging throughout the project and ultimately were the limiting factor in the energy density vs. cycle life trade off. By avoiding silicon anodes for the lower energy PHEV design, we manufactured cells with intermediate energy density and long cycle life under high voltage operation for PHEV applications. Cells with high energy density for EV applications were manufactured targeting a 300 Wh/kg design and were able to achieve > 200 cycles.

  18. Cell viability of mycorrhiza helper bacteria solid inoculant in different carrier material

    Science.gov (United States)

    Asyiah, Iis Nur; Hindersah, Reginawanti; Harni, Rita

    2018-02-01

    Roots of food crops are colonized by nonpathogenic mycorrhizal fungi which show natural ability to control plant pathogen. Mycorrhizal establishment in plant roots is affected by rhizobacteria, known as mycorrhiza helper bacteria (MHB), which has synergetic effects on mycorrhizal associations. Laboratory experiment has been conducted to assess the best carrier material to develop well-qualified MHB of Pseudomonas diminuta and Bacillus subtilis solid inoculant. Carrier materials were 100 mesh organic matter of agricultural waste. Different spore concentration of both bacterial liquid inoculants were grown on three kinds of 100-mesh organic matter and stored at room temperature up to 90 days. Cell viability of both MHB were counted by serial dilution plate method by using specific medium. The results showed that sugar cane baggase ash was the best carrier material to maintain cell viability for both MHB. However, the population of Pseudomonas diminuta and Bacillus subtilis in sugar cane baggase ash were slightly decreased after 90 days. The use of sugarcane baggase ash for solid MHB inoculant development could be suggested.

  19. Nanoarchitectures in dye-sensitized solar cells: metal oxides, oxide perovskites and carbon-based materials.

    Science.gov (United States)

    Shaikh, Jasmin S; Shaikh, Navajsharif S; Mali, Sawanta S; Patil, Jyoti V; Pawar, Krishna K; Kanjanaboos, Pongsakorn; Hong, Chang Kook; Kim, J H; Patil, Pramod S

    2018-03-15

    Dye-sensitized solar cells (DSSCs) have aroused great interest and been regarded as a potential renewable energy resource among the third-generation solar cell technologies to fulfill the 21 st century global energy demand. DSSCs have notable advantages such as low cost, easy fabrication process and being eco-friendly in nature. The progress of DSSCs over the last 20 years has been nearly constant due to some limitations, like poor long-term stability, narrow absorption spectrum, charge carrier transportation and collection losses and poor charge transfer mechanism for regeneration of dye molecules. The main challenge for the scientific community is to improve the performance of DSSCs by using different approaches, like finding new electrode materials with suitable nanoarchitectures, dyes in composition with promising semiconductors and metal quantum dot fluorescent dyes, and cost-effective hole transporting materials (HTMs). This review focuses on DSSC photo-physics, which includes charge separation, effective transportation, collection and recombination processes. Different nanostructured materials, including metal oxides, oxide perovskites and carbon-based composites, have been studied for photoanodes, and counter electrodes, which are crucial to achieve DSSC devices with higher efficiency and better stability.

  20. Recent Development of Graphene-Based Cathode Materials for Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Man-Ning Lu

    2016-01-01

    Full Text Available Dye-sensitized solar cells (DSSCs have attracted extensive attention for serving as potential low-cost alternatives to silicon-based solar cells. As a vital role of a typical DSSC, the counter electrode (CE is generally employed to collect electrons via the external circuit and speed up the reduction reaction of I3- to I- in the redox electrolyte. The noble Pt is usually deposited on a conductive glass substrate as CE material due to its excellent electrical conductivity, electrocatalytic activity, and electrochemical stability. To achieve cost-efficient DSSCs, reasonable efforts have been made to explore Pt-free alternatives. Recently, the graphene-based CEs have been intensively investigated to replace the high-cost noble Pt CE. In this paper, we provided an overview of studies on the electrochemical and photovoltaic characteristics of graphene-based CEs, including graphene, graphene/Pt, graphene/carbon materials, graphene/conducting polymers, and graphene/inorganic compounds. We also summarize the design and advantages of each graphene-based material and provide the possible directions for designing new graphene-based catalysts in future research for high-performance and low-cost DSSCs.

  1. Foreign Body Giant Cell-Related Encapsulation of a Synthetic Material Three Years After Augmentation.

    Science.gov (United States)

    Lorenz, Jonas; Barbeck, Mike; Sader, Robert A; Kirkpatrick, Charles J; Russe, Philippe; Choukroun, Joseph; Ghanaati, Shahram

    2016-06-01

    Bone substitute materials of different origin and chemical compositions are frequently used in augmentation procedures to enlarge the local bone amount. However, relatively little data exist on the long-term tissue reactions. The presented case reports for the first time histological and histomorphometrical analyses of a nanocrystaline hydroxyapatite-based bone substitute material implanted in the human sinus cavity after an integration period of 3 years. The extracted biopsy was analyzed histologically and histomorphometrically with focus on the tissue reactions, vascularization, new bone formation, and the induction of a foreign body reaction. A comparably high rate of connective tissue (48.25%) surrounding the remaining bone substitute granules (42.13%) was observed. Accordingly, the amount of bone tissue (9.62%) built the smallest fraction within the biopsy. Further, tartrate-resistant acid phosphatase-positive and -negative multinucleated giant cells (4.35 and 3.93 cells/mm(2), respectively) were detected on the material-tissue interfaces. The implantation bed showed a mild vascularization of 10.03 vessels/mm(2) and 0.78%. The present case report shows that after 3 years, a comparable small amount of bone tissue was observable. Thus, the foreign body response to the bone substitute seems to be folded without further degradation or regeneration.

  2. Fuel cell studies of perovskite-type materials for IT-SOFC

    Science.gov (United States)

    Peña-Martínez, J.; Marrero-López, D.; Ruiz-Morales, J. C.; Buergler, B. E.; Núñez, P.; Gauckler, L. J.

    The electrochemical performance of solid oxide fuel cells (SOFCs) based on perovskite-type materials (ABO 3) was investigated. La 0.9Sr 0.1Ga 0.8Mg 0.2O 3- δ (LSGM) ceramics were used as electrolyte and a composite containing La 0.8Sr 0.2MnO 3 (LSM) as cathode. Ba 0.5Sr 0.5Co 0.8Fe 0.2O 3- δ (BSCF) was also used as cathode and La 0.75Sr 0.25Cr 0.5Mn 0.5O 3- δ (LSCM) as anode materials. Furthermore, fluorite-type Sm 0.15Ce 0.85O 2- δ (SDC) material was used as buffer layer between the electrolyte and the anode to avoid possible interfacial reactions. The maximum power density value of BSCF/LSGM/LSCM with 1.5 mm thick electrolyte supported cell was 160 mW cm -2 at 1073 K, using moist H 2 diluted with N 2 as fuel and air as oxidant.

  3. Biological Effects of Provisional Resin Materials on Human Dental Pulp Stem Cells.

    Science.gov (United States)

    Jun, S-K; Mahapatra, C; Lee, H-H; Kim, H-W; Lee, J-H

    This study investigated the in vitro cytotoxicity as well as the proinflammatory cytokine expression of provisional resin materials on primary cultured human dental pulp stem cells (hDPSCs). Five commercially available provisional resin materials were chosen (SNAP [SN], Luxatemp [LT], Jet [JE], Revotek LC [RL], and Vipi block [VB]). Eluates that were either polymerizing or already set were added to hDPSCs under serially diluted conditions divided into three different setting times (25% set, 50% set, and 100% set) and incubated for 24 hours with 2× concentrated culture media. Cell cytotoxicity tests were performed by LDH assay and live and dead confocal microscope images. The expression of proinflammatory cytokines in SN and VB was measured using cytokine antibody arrays. Data were analyzed using repeated measures analysis of variance (ANOVA) or ANOVA followed by the Tukey post hoc test at a significance level of pprovisional resin materials during polymerization (SN, LT, and JE) were cytotoxic to hDPSCs and may adversely affect pulp tissue.

  4. A comprehensive device modelling of perovskite solar cell with inorganic copper iodide as hole transport material

    Science.gov (United States)

    Zulqarnain Haider, Syed; Anwar, Hafeez; Wang, Mingqing

    2018-03-01

    Hole transport material (HTM) plays an important role in the efficiency and stability of perovskite solar cells (PSCs). Spiro-MeOTAD, the commonly used HTM, is costly and can be easily degraded by heat and moisture, thus offering hindrance to commercialize PSCs. There is dire need to find an alternate inorganic and stable HTM to exploit PSCs with their maximum capability. In this paper, a comprehensive device simulation is used to study various possible parameters that can influence the performance of perovskite solar cell with CuI as HTM. These include the effect of doping density, defect density and thickness of absorber layer, along with the influence of diffusion length of carriers as well as electron affinity of electron transport layer (ETM) and HTM on the performance of PSCs. In addition, hole mobility and doping density of HTM is also investigated. CuI is a p-type inorganic material with low cost and relatively high stability. It is found that concentration of dopant in absorber layer and HTM, the electron affinity of HTM and ETM affect the performance of solar cell minutely, while cell performance improves greatly with the reduction of defect density. Upon optimization of parameters, power conversion efficiency for this device is found to be 21.32%. The result shows that lead-based PSC with CuI as HTM is an efficient system. Enhancing the stability and reduction of defect density are critical factors for future research. These factors can be improved by better fabrication process and proper encapsulation of solar cell.

  5. 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.

  6. 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)

  7. 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.

  8. Ternary solution-processed organic solar cells incorporating 2D materials

    Science.gov (United States)

    Stylianakis, Minas M.; Konios, Dimitrios; Petridis, Constantinos; Kakavelakis, George; Stratakis, Emmanuel; Kymakis, Emmanuel

    2017-12-01

    Recently, the study of ternary organic solar cells (OSCs) has attracted the efforts of the scientific community, leading to significantly higher performance due to the enhanced harvesting of incoming irradiation. Here, for the first time, and in order to promote this OSC architecture, we review the progress implemented by the application of two-dimensional (2D) materials in the field of blend bulk heterojunction ternary OSCs. Power conversion efficiency (PCE) improvements of the order of 40% compared to the reference binary devices, and PCEs in excess of 8% have been reported by incorporating graphene-based or other 2D materials as a third element inside the active layer. These OSCs combine the synergetic advantages of ternary devices and the superb properties of the 2D material family. In conclusion, the incorporation of the unique properties of graphene and other 2D materials inside the active layer opens up a very promising pathway in the design and construction of high-performance, simply fabricated and low- cost photovoltaic devices.

  9. 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)

  10. Perovskite Solar Cells with ZnO Electron-Transporting Materials.

    Science.gov (United States)

    Zhang, Peng; Wu, Jiang; Zhang, Ting; Wang, Yafei; Liu, Detao; Chen, Hao; Ji, Long; Liu, Chunhua; Ahmad, Waseem; Chen, Zhi David; Li, Shibin

    2018-01-01

    Perovskite solar cells (PSCs) have developed rapidly over the past few years, and the power conversion efficiency of PSCs has exceeded 20%. Such high performance can be attributed to the unique properties of perovskite materials, such as high absorption over the visible range and long diffusion length. Due to the different diffusion lengths of holes and electrons, electron transporting materials (ETMs) used in PSCs play a critical role in PSCs performance. As an alternative to TiO 2 ETM, ZnO materials have similar physical properties to TiO 2 but with much higher electron mobility. In addition, there are many simple and facile methods to fabricate ZnO nanomaterials with low cost and energy consumption. This review focuses on recent developments in the use of ZnO ETM for PSCs. The fabrication methods of ZnO materials are briefly introduced. The influence of different ZnO ETMs on performance of PSCs is then reviewed. The limitations of ZnO ETM-based PSCs and some solutions to these challenges are also discussed. The review provides a systematic and comprehensive understanding of the influence of different ZnO ETMs on PSCs performance and potentially motivates further development of PSCs by extending the knowledge of ZnO-based PSCs to TiO 2 -based PSCs. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Mesoporous TiO2 : an alternative material for PEM fuel cells catalyst support

    Energy Technology Data Exchange (ETDEWEB)

    Do, T.B. [Michigan Univ., Ann Arbor, MI (United States). Dept. of Materials Science; Ruthkosky, M.; Cai, M. [General Motors, Warren, MI (United States). Research and Development Center

    2008-07-01

    This paper discussed the feasibility of using an alternative catalyst support material to replace carbon in proton exchange membrane (PEM) fuel cells. The alternative catalyst support material requires a high surface area with a large porosity but must have comparable conductivity with carbon. A mesoporous titanium oxide (TiO2) material produced by coprecipitation was introduced. The conductivity of the material is about one order of that of carbon. The 8 mole per cent Nb-doped TiO2 was formed and deposited on the surface of a nano polystyrene (PS) template via the hydrolysis of a co-solution of Ti(OC4H9)4 and Nb(OC2H5)5. The removal of PS by heat treatment produced porous structure of TiO2 with the appearance of 3 different pore types, notably open pore, ink-pot pores and closed pores. TiO2 formed from the rutile phase, allowing a lower activation temperature at 850 degrees C in a hydrogen atmosphere. The pore structures were retained after this heat treatment. The BET surface area was 116 m{sup 2}/g, porosity was 22 per cent and the average pore size was 159 angstrom. The conductivity improved considerably from almost non-conductive to one order of that of carbon.

  12. Nanostructured Carbon Materials as Supports in the Preparation of Direct Methanol Fuel Cell Electrocatalysts

    Directory of Open Access Journals (Sweden)

    María Jesús Lázaro

    2013-08-01

    Full Text Available Different advanced nanostructured carbon materials, such as carbon nanocoils, carbon nanofibers, graphitized ordered mesoporous carbons and carbon xerogels, presenting interesting features such as high electrical conductivity and extensively developed porous structure were synthesized and used as supports in the preparation of electrocatalysts for direct methanol fuel cells (DMFCs. The main advantage of these supports is that their physical properties and surface chemistry can be tailored to adapt the carbonaceous material to the catalytic requirements. Moreover, all of them present a highly mesoporous structure, diminishing diffusion problems, and both graphitic character and surface area can be conveniently modified. In the present work, the influence of the particular features of each material on the catalytic activity and stability was analyzed. Results have been compared with those obtained for commercial catalysts supported on Vulcan XC-72R, Pt/C and PtRu/C (ETEK. Both a highly ordered graphitic and mesopore-enriched structure of these advanced nanostructured materials resulted in an improved electrochemical performance in comparison to the commercial catalysts assayed, both towards CO and alcohol oxidation.

  13. 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.

  14. Fracture criterion for brittle materials based on statistical cells of finite volume

    International Nuclear Information System (INIS)

    Cords, H.; Kleist, G.; Zimmermann, R.

    1986-06-01

    An analytical consideration of the Weibull Statistical Analysis of brittle materials established the necessity of including one additional material constant for a more comprehensive description of the failure behaviour. The Weibull analysis is restricted to infinitesimal volume elements in consequence of the differential calculus applied. It was found that infinitesimally small elements are in conflict with the basic statistical assumption and that the differential calculus is not needed in fact since nowadays most of the stress analyses are based on finite element calculations, and these are most suitable for a subsequent statistical analysis of strength. The size of a finite statistical cell has been introduced as the third material parameter. It should represent the minimum volume containing all statistical features of the material such as distribution of pores, flaws and grains. The new approach also contains a unique treatment of failure under multiaxial stresses. The quantity responsible for failure under multiaxial stresses is introduced as a modified strain energy. Sixteen different tensile specimens including CT-specimens have been investigated experimentally and analyzed with the probabilistic fracture criterion. As a result it can be stated that the failure rates of all types of specimens made from three different grades of graphite are predictable. The accuracy of the prediction is one standard deviation. (orig.) [de

  15. Toward new fuel cell support materials: a theoretical and experimental study of nitrogen-doped graphene.

    Science.gov (United States)

    Seo, Min Ho; Choi, Sung Mook; Lim, Eun Ja; Kwon, In Hye; Seo, Joon Kyo; Noh, Seung Hyo; Kim, Won Bae; Han, Byungchan

    2014-09-01

    Nano-scale Pt particles are often reported to be more electrochemically active and stable in a fuel cell if properly displaced on support materials; however, the factors that affect their activity and stability are not well understood. We applied first-principles calculations and experimental measurements to well-defined model systems of N-doped graphene supports (N-GNS) to reveal the fundamental mechanisms that control the catalytic properties and structural integrity of nano-scale Pt particles. DFT calculations predict thermodynamic and electrochemical interactions between N-GNS and Pt nanoparticles in the methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR). Moreover, the dissolution potentials of the Pt nanoparticles supported on GNS and N-GNS catalysts are calculated under acidic conditions. Our results provide insight into the design of new support materials for enhanced catalytic efficiency and long-term stability. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Mechanism of chromium poisoning the conventional cathode material for solid oxide fuel cells

    Science.gov (United States)

    Zhang, Xiaoqiang; Yu, Guangsen; Zeng, Shumao; Parbey, Joseph; Xiao, Shuhao; Li, Baihai; Li, Tingshuai; Andersson, Martin

    2018-03-01

    Chromium poisoning the La0.875Sr0.125MnO3 (LSM) cathode for solid oxide fuel cells is a critical issue that can strongly affect the stability. In this study, we evaluate the temperature distribution in a SOFC based on a 3D model and then combine conductivity test and material computation to reveal the effects of chromium in SUS430 stainless steels on LSM conductivities. The starch concentration in LSM pellets and the applied pressure on the contact with interconnect materials show close relationships with the chromium poisoning behavior. The density functional theory (DFT) computing results indicate that chromium atoms preferably adsorb on the MnO2-terminated and La (Sr)-O-terminated (001) surfaces. The resulting conclusions are expected to deeply understand mechanism of chromium deactivating conventional cathodes at some typical operational conditions, and offer crucial information to optimize the structure to avoid the poisoning effect.

  17. Engineered Graphene Materials: Synthesis and Applications for Polymer Electrolyte Membrane Fuel Cells.

    Science.gov (United States)

    He, Daping; Tang, Haolin; Kou, Zongkui; Pan, Mu; Sun, Xueliang; Zhang, Jiujun; Mu, Shichun

    2017-05-01

    Engineered graphene materials (EGMs) with unique structures and properties have been incorporated into various components of polymer electrolyte membrane fuel cells (PEMFCs) such as electrode, membrane, and bipolar plates to achieve enhanced performances in terms of electrical conductivity, mechanical durability, corrosion resistance, and electrochemical surface area. This research news article provides an overview of the recent development in EGMs and EGM-based PEMFCs with a focus on the effects of EGMs on PEMFC performance when they are incorporated into different components of PEMFCs. The challenges of EGMs for practical PEMFC applications in terms of production scale, stability, conductivity, and coupling capability with other materials are also discussed and the corresponding measures and future research trends to overcome such challenges are proposed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. 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.

  19. Design of broadband absorber using 2-D materials for thermo-photovoltaic cell application

    Science.gov (United States)

    Agarwal, Sajal; Prajapati, Y. K.

    2018-04-01

    Present study is done to analyze a nano absorber for thermo-photovoltaic cell application. Optical absorbance of two-dimensional materials is exploited to achieve high absorbance. It is found that few alternating layers of graphene/transition metal dichalcogenide provide high absorbance of electromagnetic wave in visible as well as near infrared region. Four transition metal dichalcogenides are considered and found that most of these provide perfect absorbance for almost full considered wavelength range i.e. 200-1000 nm. Demonstrated results confirm the extended operating region and improved absorbance of the proposed absorber in comparison to the existing absorbers made of different materials. Further, absorber performance is improved by using thin layers of gold and chromium. Simple geometry of the proposed absorber also ensures easy fabrication.

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

    International Nuclear Information System (INIS)

    Fabbri, Emiliana; Pergolesi, Daniele; Traversa, Enrico

    2010-01-01

    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 0 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. (topical review)

  1. 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.

  2. Liquid electrolyte-free, solid-state solar cells with inorganic hole transport materials

    Science.gov (United States)

    Kanatzidis, Mercouri G.; Chung, In; Lee, Byunghong; Chang, Robert P. H.

    2017-10-31

    Photovoltaic cells incorporating the compounds A/M/X compounds as hole transport materials are provide. The A/M/X compounds comprise one or more A moieties, one or more M atoms and one or more X atoms. The A moieties are selected from organic cations and elements from Group 1 of the periodic table, the M atoms are selected from elements from at least one of Groups 3, 4, 5, 13, 14 or 15 of the periodic table, and the X atoms are selected from elements from Group 17 of the periodic table.

  3. 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 samples following this annealing step....

  4. Perovskite Thin Film Solar Cells Based on Inorganic Hole Conducting Materials

    Directory of Open Access Journals (Sweden)

    Pan-Pan Zhang

    2017-01-01

    Full Text Available Organic-inorganic metal halide perovskites have recently shown great potential for application, due to their advantages of low-cost, excellent photoelectric properties and high power conversion efficiency. Perovskite-based thin film solar cells have achieved a power conversion efficiency (PCE of up to 20%. Hole transport materials (HTMs are one of the most important components of perovskite solar cells (PSCs, having functions of optimizing interface, adjusting the energy match, and helping to obtain higher PCE. Inorganic p-type semiconductors are alternative HTMs due to their chemical stability, higher mobility, high transparency in the visible region, and applicable valence band (VB energy level. This review analyzed the advantages, disadvantages, and development prospects of several popular inorganic HTMs in PSCs.

  5. Application of dopant-free hole transport materials for perovskite solar cells

    International Nuclear Information System (INIS)

    Franckevincius, M.; Gulbinas, V.; Gratzel, M.; Zakeeruddin, S.; Pauerle, P.; Mishra, A.; Steck, C.

    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 (CH 3 NH 3 PbI 3 ) perovskite. Dopant-free perovskite solar cells have been fabricated using CH 3 NH 3 PbI 3 perovskite and the newly synthesized HTMs following sequential deposition method, which allows us to reach power conversion efficiencies as high as 11.4 %. The easy of synthesis, low cost and relatively high performance of newly synthesized HTMs has great prospects for commercial applications in the near-future. (authors)

  6. 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

  7. 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

  8. Designed Materials for Enhanced Oxygen Reduction Electrocatalysis in PEM Fuel Cells: Novel Materials and Next Generation Synchrotron Based in Situ

    Science.gov (United States)

    2005-11-15

    fonnation at the electrocatalyst- ionomer interface in a PEM fuel cell context is especially important from the perspective ofattempts to develop alternative...Reduction in a Fully Hydrated Proton Exchange Membrane Interface : Problems and Prospects’, S. Mukerjee. Keynote speaker at International Fuel Cells , May 15th...Synchrotron XAS Investigation’S. Mukerjee, invited speaker at the Workshop on Theory and Surface Measurement of Fuel Cell Catalysts , Magleas Conference

  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. Materials and characterization techniques for high-temperature polymer electrolyte membrane fuel cells.

    Science.gov (United States)

    Zeis, Roswitha

    2015-01-01

    The performance of high-temperature polymer electrolyte membrane fuel cells (HT-PEMFC) is critically dependent on the selection of materials and optimization of individual components. A conventional high-temperature membrane electrode assembly (HT-MEA) primarily consists of a polybenzimidazole (PBI)-type membrane containing phosphoric acid and two gas diffusion electrodes (GDE), the anode and the cathode, attached to the two surfaces of the membrane. This review article provides a survey on the materials implemented in state-of-the-art HT-MEAs. These materials must meet extremely demanding requirements because of the severe operating conditions of HT-PEMFCs. They need to be electrochemically and thermally stable in highly acidic environment. The polymer membranes should exhibit high proton conductivity in low-hydration and even anhydrous states. Of special concern for phosphoric-acid-doped PBI-type membranes is the acid loss and management during operation. The slow oxygen reduction reaction in HT-PEMFCs remains a challenge. Phosphoric acid tends to adsorb onto the surface of the platinum catalyst and therefore hampers the reaction kinetics. Additionally, the binder material plays a key role in regulating the hydrophobicity and hydrophilicity of the catalyst layer. Subsequently, the binder controls the electrode-membrane interface that establishes the triple phase boundary between proton conductive electrolyte, electron conductive catalyst, and reactant gases. Moreover, the elevated operating temperatures promote carbon corrosion and therefore degrade the integrity of the catalyst support. These are only some examples how materials properties affect the stability and performance of HT-PEMFCs. For this reason, materials characterization techniques for HT-PEMFCs, either in situ or ex situ, are highly beneficial. Significant progress has recently been made in this field, which enables us to gain a better understanding of underlying processes occurring during fuel cell

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

    International Nuclear Information System (INIS)

    Suarez-Franco, J.L.; Fernandez-Pedrero, J.A.; Ivarez-Perez, M.A.; Garcia-Hipolito, M.; Surarez-Rosales, M.; Fregoso, O.; Juarez-Islas, J.A.; Ivarez-Perez, M.A.

    2013-01-01

    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 ZnAl 2 O 4 prepared by spray pyrolysis and bulk pellets of polycrystalline ZnAl 2 O 4 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 ZnAl 2 O 4 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 ZnAl 2 O 4 prepared by spray pyrolysis and bulk pellets of polycrystalline ZnAl 2 O 4 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 ZnAl 2 O 4 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

  12. Spatio-temporal diversification of the cell wall matrix materials in the developing stomatal complexes of Zea mays.

    Science.gov (United States)

    Giannoutsou, E; Apostolakos, P; Galatis, B

    2016-11-01

    The matrix cell wall materials, in developing Zea mays stomatal complexes are asymmetrically distributed, a phenomenon appearing related to the local cell wall expansion and deformation, the establishment of cell polarity, and determination of the cell division plane. In cells of developing Zea mays stomatal complexes, definite cell wall regions expand determinately and become locally deformed. This differential cell wall behavior is obvious in the guard cell mother cells (GMCs) and the subsidiary cell mother cells (SMCs) that locally protrude towards the adjacent GMCs. The latter, emitting a morphogenetic stimulus, induce polarization/asymmetrical division in SMCs. Examination of immunolabeled specimens revealed that homogalacturonans (HGAs) with a high degree of de-esterification (2F4- and JIM5-HGA epitopes) and arabinogalactan proteins are selectively distributed in the extending and deformed cell wall regions, while their margins are enriched with rhamnogalacturonans (RGAs) containing highly branched arabinans (LM6-RGA epitope). In SMCs, the local cell wall matrix differentiation constitutes the first structural event, indicating the establishment of cell polarity. Moreover, in the premitotic GMCs and SMCs, non-esterified HGAs (2F4-HGA epitope) are preferentially localized in the cell wall areas outlining the cytoplasm where the preprophase band is formed. In these areas, the forthcoming cell plate fuses with the parent cell walls. These data suggest that the described heterogeneity in matrix cell wall materials is probably involved in: (a) local cell wall expansion and deformation, (b) the transduction of the inductive GMC stimulus, and (c) the determination of the division plane in GMCs and SMCs.

  13. 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.

  14. Evaluation of materials for bipolar plates in simulated PEM fuel-cell cathodic environments

    Energy Technology Data Exchange (ETDEWEB)

    Rivas, S.V.; Belmonte, M.R.; Moron, L.E.; Torres, J.; Orozco, G. [Centro de Investigacion y Desarrollo Technologico en Electroquimica S.C. Parcque Sanfandila, Queretaro (Mexico); Perez-Quiroz, J.T. [Mexican Transport Inst., Queretaro (Mexico); Cortes, M. A. [Mexican Petroleum Inst., Mexico City (Mexico)

    2008-04-15

    The bipolar plates in proton exchange membrane fuel cells (PEMFC) are exposed to an oxidizing environment on the cathodic side, and therefore are susceptible to corrosion. Corrosion resistant materials are needed for the bipolar plates in order to improve the lifespan of fuel cells. This article described a study in which a molybdenum (Mo) coating was deposited over austenitic stainless steel 316 and carbon steel as substrates in order to evaluate the resulting surfaces with respect to their corrosion resistance in simulated anodic and cathodic PEMFC environments. The molybdenum oxide films were characterized by scanning electron microscopy (SEM) and Raman spectroscopy. The article presented the experiment and discussed the results of the corrosion behaviour of coated stainless steel. In general, the electrochemical characterization of bare materials and coated steel consisted of slow potentiodynamic polarization curves followed by a constant potential polarization test. The test medium was 0.5M sulfuric acid with additional introduction of oxygen to simulate the cathodic environment. All tests were performed at ambient temperature and at 50 degrees Celsius. The potentiostat used was a Gamry instrument. It was concluded that it is possible to deposit Mo-oxides on steel without using another alloying metal. The preferred substrate for corrosion prevention was found to be an alloy with high chromium content. 24 refs., 4 figs.

  15. Advanced passivation techniques for Si solar cells with high-κ dielectric materials

    Science.gov (United States)

    Geng, Huijuan; Lin, Tingjui; Letha, Ayra Jagadhamma; Hwang, Huey-Liang; Kyznetsov, Fedor A.; Smirnova, Tamara P.; Saraev, Andrey A.; Kaichev, Vasily V.

    2014-09-01

    Electronic recombination losses at the wafer surface significantly reduce the efficiency of Si solar cells. Surface passivation using a suitable thin dielectric layer can minimize the recombination losses. Herein, advanced passivation using simple materials (Al2O3, HfO2) and their compounds H(Hf)A(Al)O deposited by atomic layer deposition (ALD) was investigated. The chemical composition of Hf and Al oxide films were determined by X-ray photoelectron spectroscopy (XPS). The XPS depth profiles exhibit continuous uniform dense layers. The ALD-Al2O3 film has been found to provide negative fixed charge (-6.4 × 1011 cm-2), whereas HfO2 film provides positive fixed charge (3.2 × 1012 cm-2). The effective lifetimes can be improved after oxygen gas annealing for 1 min. I-V characteristics of Si solar cells with high-κ dielectric materials as passivation layers indicate that the performance is significantly improved, and ALD-HfO2 film would provide better passivation properties than that of the ALD-Al2O3 film in this research work.

  16. Advanced passivation techniques for Si solar cells with high-κ dielectric materials

    International Nuclear Information System (INIS)

    Geng, Huijuan; Lin, Tingjui; Letha, Ayra Jagadhamma; Hwang, Huey-Liang; Kyznetsov, Fedor A.; Smirnova, Tamara P.; Saraev, Andrey A.; Kaichev, Vasily V.

    2014-01-01

    Electronic recombination losses at the wafer surface significantly reduce the efficiency of Si solar cells. Surface passivation using a suitable thin dielectric layer can minimize the recombination losses. Herein, advanced passivation using simple materials (Al 2 O 3 , HfO 2 ) and their compounds H (Hf) A (Al) O deposited by atomic layer deposition (ALD) was investigated. The chemical composition of Hf and Al oxide films were determined by X-ray photoelectron spectroscopy (XPS). The XPS depth profiles exhibit continuous uniform dense layers. The ALD-Al 2 O 3 film has been found to provide negative fixed charge (−6.4 × 10 11  cm −2 ), whereas HfO 2 film provides positive fixed charge (3.2 × 10 12  cm −2 ). The effective lifetimes can be improved after oxygen gas annealing for 1 min. I-V characteristics of Si solar cells with high-κ dielectric materials as passivation layers indicate that the performance is significantly improved, and ALD-HfO 2 film would provide better passivation properties than that of the ALD-Al 2 O 3 film in this research work.

  17. Cytotoxicity of Various Endodontic Materials on Stem Cells of Human Apical Papilla.

    Science.gov (United States)

    Saberi, Eshagh Ali; Karkehabadi, Hamed; Mollashahi, Narges Farhad

    2016-01-01

    This in vitro study assessed and compared the cytotoxicity of mineral trioxide aggregate (MTA), calcium-enriched mixture (CEM) cement, Biodentine (BD) and octacalcium phosphate (OCP) on stem cells of the human apical papilla (SCAP). SCAPs were isolated from two semi-impacted third molars. The cells were cultured in wells of an insert 24-well plate and were then incubated. The plates were then removed from the incubator and randomly divided into four experimental groups that were exposed to 1-mm discs of set MTA, CEM, BD or OCP, and one untreated control group. After 24, 48 and 168 h, the plates were removed from the incubator and 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl tetrazolium bromide (MTT) solution was added to each well. Data were analyzed at different time points using the repeated measures ANOVA followed by Bonferroni test and the level of significance was set at 0.05. Cytotoxicity of the four materials was not significantly different from that of the control group at 24, 48 and 168 h (P>0.05). Two-by-two comparison revealed that cytotoxicity of MTA and CEM cement was significantly different from each other at 168 h (Pcytotoxicity of CEM was less than MTA. Cytotoxicity of OCP and MTA was also significantly different from each other at 48 h and OCP had more favorable biocompatibility than MTA (Pcytotoxicity among the materials under study.

  18. In-situ X-ray Nanocharacterization of Defect Kinetics in Chalcogenide Solar Cell Materials

    Energy Technology Data Exchange (ETDEWEB)

    Bertoni, Mariana [Arizona State Univ., Tempe, AZ (United States); Lai, Barry [Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS); Masser, Jorg [Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS); Buonassisi, Tonio [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2016-09-21

    For decades the optimization of polycrystalline absorbers has been done using an Edisonian approach, where trial and error and complex design of experiments in large parameter spaces have driven efficiencies to the record values we see today – CIGS at 22.5%, 22.1% for CdTe, 21.3% for high purity multi-crystalline silicon. Appropriate growth parameters are critical to ensure good quality crystals with low concentration of structural defects - low dislocation density and large grain sizes. However, to bridge the gap between the efficiencies today and the fundamental Shockley-Queisser limit for these materials a much more fundamental understanding of the role and interaction between composition, structure, defect density and electrical properties is required. In recent years multiple novel characterization techniques have shown the potential that nanoscale characterization can have in deciphering the composition of grain boundaries in materials like CIGS and CdTe. However, high resolution has come at the cost of small sampling areas and number of specimens, making it extremely difficult to draw conclusions based on the characteristic small sampling sizes. The missing links thus far have been: (1) the lack of statistical meaningfulness of the nanosclae studies and (2) the direct correlation of compositional variations to electrical performance with nanoscale resolution. In this work we present the use of synchrotron-based nano-X-ray fluorescence microscopy (nano-XRF), x-ray absorption nanospectroscopy (nano-XAS) coupled with nano-x-ray beam induced current (nano-XBIC) as ideal tools for investigating elemental, chemical and electrical properties of large areas of solar cell materials at the sub-micron scale with very high sensitivity. We show how the technique can provide statistical valuable information regarding the elemental segregation in CIGS and the direct correlation to current collection. For example, we demonstrate that Cu and Ga (and with that, CGI and GGI

  19. 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.

  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. New, Efficient, and Reliable Air Electrode Material for Proton-Conducting Reversible Solid Oxide Cells.

    Science.gov (United States)

    Huan, Daoming; Shi, Nai; Zhang, Lu; Tan, Wenzhou; Xie, Yun; Wang, Wanhua; Xia, Changrong; Peng, Ranran; Lu, Yalin

    2018-01-17

    Driven by the demand to minimize fluctuation in common renewable energies, reversible solid oxide cells (RSOCs) have drawn increasing attention for they can operate either as fuel cells to produce electricity or as electrolysis cells to store electricity. Unfortunately, development of proton-conducting RSOCs (P-RSOCs) faces a major challenge of poor reliability because of the high content of steam involved in air electrode reactions, which could seriously decay the lifetime of air electrode materials. In this work, a very stable and efficient air electrode, SrEu 2 Fe 1.8 Co 0.2 O 7-δ (SEFC) with layer structure, is designed and deployed in P-RSOCs. X-ray diffraction analysis and High-angle annular dark-filed scanning transmission electron microscopy images of SEFC reveal that Sr atoms occupy the center of perovskite slabs, whereas Eu atoms arrange orderly in the rock-salt layer. Such a special structure of SEFC largely depresses its Lewis basicity and therefore its reactivity with steam. Applying the SEFC air electrode, our button switches smoothly between both fuel cell and electrolysis cell (EC) modes with no obvious degradation over a 135 h long-term test under wet H 2 (∼3% H 2 O) and 10% H 2 O-air atmospheres. A record of over 230 h is achieved in the long-term stability test in the EC mode, doubling the longest test that had been previously reported. Besides good stability, SEFC demonstrates great catalytic activity toward air electrode reactions when compared with traditional La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ air electrodes. This research highlights the potential of stable and efficient P-RSOCs as an important part in a sustainable new energy power system.

  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. Lifetime and diffusion length measurements on silicon material and solar cells. [Intentionally doped with impurities

    Energy Technology Data Exchange (ETDEWEB)

    Othmer, S.; Chen, S.C.

    1977-01-01

    Experimental methods were evaluated for the determination of lifetime and diffusion length in silicon intentionally doped with potentially lifetime-degrading impurities found in metallurgical grade silicon, impurities which may be residual in low-cost silicon intended for use in terrestrial flat-plat arrays. Results obtained by these methods were compared for mutual consistency. Lifetime measurements were made using a steady-state photoconductivity method, which was compared with a photoconductivity decay technique. Diffusion length determinations were made using short-circuit current measurements under penetrating illumination. This method was compared with a direct measurement of diffusion length using a scanning electron microscope. Mutual consistency among all experimental methods was verified, but steady-state photoconductivity was found preferable to photoconductivity decay at short lifetimes and in the presence of traps. The effects of a number of impurities on lifetime in bulk material, and on diffusion length in cells fabricated from this material, were determined. Results were compared with those obtained by others on the same material and devices using different techniques. General agreement was found in terms of the hierarchy of impurities which degrade the lifetime.

  4. 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.

  5. 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

  6. Aberrant expression of cell cycle and material metabolism related genes contributes to hepatocellular carcinoma occurrence.

    Science.gov (United States)

    Yan, Hongxian; Li, Zhaohui; Shen, Quan; Wang, Qian; Tian, Jianguo; Jiang, Qingfeng; Gao, Linbo

    2017-04-01

    This study aims to deepen our understanding of the molecular mechanism underlying the occurrence of hepatocellular carcinoma (HCC). We first downloaded a gene expression profile dataset GSE29721 (10 HCC and 10 control samples) from Gene Expression Omnibus database (http://www.ncbi.nlm.nih.gov/geo/). Differentially expressed genes (DEGs) were identified by the paired t-test using limma package. Pathway and functional enrichment analyses were performed with DAVID tools. Transcription factors were annotated with TRANSFAC database and tumor associated genes (TAGs) were annotated with TAG and TSGene databases. Protein-protein interaction (PPI) network was conducted using STRING online tool and function module was further identified with BioNet package. Totally, 527 up-regulated DEGs and 587 down-regulated DEGs were identified. GO functional and KEGG pathway enrichment analyses showed that the up-regulated DEGs were mainly related to cell division and cell cycle, while the down-regulated DEGs were largely related to material metabolism, especially secondary metabolism. Proteins encoded by DEGs CDK1, BUB1, CDC20, NCAPG, NDC80, CDCA8, MAD2L1, CCNB1, CCNA2 and BIRC5 were hub genes with high degrees in the PPI network; further module analysis detected a subnetwork consisting of 55 proteins, such as CYP2B6, ACAA1, BHMT and ALDH2. Taken together, aberrant expression of cell cycle related genes (e.g., CDK1, CCNA2, CCNB1, BUB1, MAD2L1 and CDC20) and material metabolism related genes (e.g., CYP2B6, ACAA1, BHMT and ALDH2) may contribute to HCC occurrence. Copyright © 2017 Elsevier GmbH. All rights reserved.

  7. Integrated micro/nanoengineered functional biomaterials for cell mechanics and mechanobiology: a materials perspective.

    Science.gov (United States)

    Shao, Yue; Fu, Jianping

    2014-03-12

    The rapid development of micro/nanoengineered functional biomaterials in the last two decades has empowered materials scientists and bioengineers to precisely control different aspects of the in vitro cell microenvironment. Following a philosophy of reductionism, many studies using synthetic functional biomaterials have revealed instructive roles of individual extracellular biophysical and biochemical cues in regulating cellular behaviors. Development of integrated micro/nanoengineered functional biomaterials to study complex and emergent biological phenomena has also thrived rapidly in recent years, revealing adaptive and integrated cellular behaviors closely relevant to human physiological and pathological conditions. Working at the interface between materials science and engineering, biology, and medicine, we are now at the beginning of a great exploration using micro/nanoengineered functional biomaterials for both fundamental biology study and clinical and biomedical applications such as regenerative medicine and drug screening. In this review, an overview of state of the art micro/nanoengineered functional biomaterials that can control precisely individual aspects of cell-microenvironment interactions is presented and they are highlighted them as well-controlled platforms for mechanistic studies of mechano-sensitive and -responsive cellular behaviors and integrative biology research. The recent exciting trend where micro/nanoengineered biomaterials are integrated into miniaturized biological and biomimetic systems for dynamic multiparametric microenvironmental control of emergent and integrated cellular behaviors is also discussed. The impact of integrated micro/nanoengineered functional biomaterials for future in vitro studies of regenerative medicine, cell biology, as well as human development and disease models are discussed. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Material properties of LPCVD processed n-type polysilicon passivating contacts and its application in PERPoly industrial bifacial solar cells

    NARCIS (Netherlands)

    Stodolny, Maciej K.; Anker, John; Geerligs, Bart L.J.; Janssen, Gaby J.M.; van de Loo, Bas W.H.; Melskens, Jimmy; Santbergen, Rudi; Isabella, Olindo; Schmitz, Jurriaan; Lenes, Martijn; Luchies, Jan Marc; Kessels, Wilhelmus M.M.; Romijn, Ingrid

    2017-01-01

    We present a detailed material study of n+-type polysilicon (polySi) and its application as a carrier selective rear contact in a bifacial n-type solar cell comprising fire-through screen-printed metallization and 6" Cz wafers. The cells were manufactured with low-cost industrial process steps

  9. Ultrathin high band gap solar cells with improved efficiencies from the world's oldest photovoltaic material.

    Science.gov (United States)

    Todorov, Teodor K; Singh, Saurabh; Bishop, Douglas M; Gunawan, Oki; Lee, Yun Seog; Gershon, Talia S; Brew, Kevin W; Antunez, Priscilla D; Haight, Richard

    2017-09-25

    Selenium was used in the first solid state solar cell in 1883 and gave early insights into the photoelectric effect that inspired Einstein's Nobel Prize work; however, the latest efficiency milestone of 5.0% was more than 30 years ago. The recent surge of interest towards high-band gap absorbers for tandem applications led us to reconsider this attractive 1.95 eV material. Here, we show completely redesigned selenium devices with improved back and front interfaces optimized through combinatorial studies and demonstrate record open-circuit voltage (V OC ) of 970 mV and efficiency of 6.5% under 1 Sun. In addition, Se devices are air-stable, non-toxic, and extremely simple to fabricate. The absorber layer is only 100 nm thick, and can be processed at 200 ˚C, allowing temperature compatibility with most bottom substrates or sub-cells. We analyze device limitations and find significant potential for further improvement making selenium an attractive high-band-gap absorber for multi-junction device applications.Wide band gap semiconductors are important for the development of tandem photovoltaics. By introducing buffer layers at the front and rear side of solar cells based on selenium; Todorov et al., reduce interface recombination losses to achieve photoconversion efficiencies of 6.5%.

  10. 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

  11. Lanthanum chromite materials as potential symmetrical electrodes for Solid Oxide Fuel Cells

    Directory of Open Access Journals (Sweden)

    Ruiz-Morales, J. C.

    2007-08-01

    Full Text Available A commonly used interconnector material has been tested as electrode for a new concept of Solid Oxide Fuel Cell, where the same material could be used, simultaneously, as interconnector, anode and cathode. We have found that a typical substituted chromite, such as La0.7Ca0.3CrO3-δ (LCC can be considered a good candidate for such configuration, due to its high electronic conductivity in both reducing and oxidising conditions, and moderate catalytic properties for oxygen reduction and hydrogen oxidation. The symmetrical design renders performances of 100 mWcm-2 at 950ºC, using O2 and H2 as oxidant and fuel respectively. Performances exceeding 300 mWcm-2 can be predicted for a 100μm-thick YSZ electrolyte.

    Un material comúnmente utilizado como interconector ha sido probado como electrodo para un nuevo concepto de Pila de Combustible de Óxidos Sólido, en el cual el mismo material se utiliza, simultáneamente, como interconector, ánodo y cátodo. Hemos encontrado que una cromita típica como La0.7Ca0.3CrO3-δ (LCC puede ser considerada una buena candidata para dicha configuración, debido a sus altas conductividades eléctricas tanto en condiciones reductoras como oxidantes y una aceptable actividad catalítica para la reducción del oxígeno y la oxidación del hidrógeno. El diseño simétrico permite obtener rendimientos del orden de 100mWcm-2 a 950ºC, utilizando O2 e H2 como oxidante y combustible, respectivamente. Rendimientos que superan los 300mWcm-2 pueden predecirse para pilas con electrolitos de YSZ de 100 μm de grosor.

  12. 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.

  13. Novel Contact Materials for Improved Performance CdTe Solar Cells Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Rockett, Angus [Colorado School of Mines, Golden, CO (United States); Marsillac, Sylvain [Old Dominion Univ., Norfolk, VA (United States); Collins, Robert [Univesity of Toledo

    2018-04-15

    This program has explored a number of novel materials for contacts to CdTe solar cells in order to reduce the back contact Schottky barrier to zero and produce an ohmic contact. The project tested a wide range of potential contact materials including TiN, ZrN, CuInSe2:N, a-Si:H and alloys with C, and FeS2. Improved contacts were achieved with FeS2. As part of understanding the operation of the devices and controlling the deposition processes, a number of other important results were obtained. In the process of this project and following its conclusion it led to research that resulted in seven journal articles, nine conference publications, 13 talks presented at conferences, and training of eight graduate students. The seven journal articles were published in 2015, 2016, and 2017 and have been cited, as of March 2018, 52 times (one cited 19 times and two cited 11 times). We demonstrated high levels of doping of CIS with N but electrical activity of the resulting N was not high and the results were difficult to reproduce. Furthermore, even with high doping the contacts were not good. Annealing did not improve the contacts. A-Si:H was found to produce acceptable but unstable contacts, degrading even over a day or two, apparently due to H incorporation into the CdTe. Alloying with C did not improve the contacts or stability. The transition metal nitrides produced Schottky type contacts for all materials tested. While these contacts were found to be unsatisfactory, we investigated FeS2 and found this material to be effective and comparable to the best contacts currently available. The contacts were found to be chemically stable under heat treatment and preferable to Cu doped contacts. Thus, we demonstrated an improved contact material in the course of this project. In addition, we developed new ways of controlling the deposition of CdTe and other materials, demonstrated the nature of defects in CdTe, and studied the distribution of conductivity and carrier type in Cd

  14. Low cost solar array project. Cell and module formation research area. Process research of non-CZ silicon material

    Science.gov (United States)

    1983-02-01

    Liquid diffusion masks and liquid dopants to replace the more expensive CVD SiO2 mask and gaseous diffusion processes were investigated. Silicon pellets were prepared in the silicon shot tower; and solar cells were fabricated using web grown where the pellets were used as a replenishment material. Verification runs were made using the boron dopant and liquid diffusion mask materials. The average of cells produced in these runs was 13%. The relationship of sheet resistivity, temperature, gas flows, and gas composition for the diffusion of the P-8 liquid phosphorus solution was investigated. Solar cells processed from web grown from Si shot material were evaluated, and results qualified the use of the material produced in the shot tower for web furnace feed stock.

  15. 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. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    José Luis Suárez-Franco

    2013-01-01

    Full Text Available 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 nanostructure 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 nanostructured material surface when compared with bulk ceramic surfaces. Moreover, our results showed that the balance of morphological properties of the thin film nanostructure 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 nanostructured materials have a great potential to be used in dental implant and bone substitute applications.

  17. 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)

  18. Methane steam reforming kinetics over Ni-YSZ anode materials for Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Mogensen, David

    of internal reforming has to be carefully controlled. The objective of this thesis is to make such a careful control possible by examining the rate of internal steam reforming in SOFCs. The catalytic steam reforming activity of Ni-YSZ anode material was tested both in a packed bed reactor to determine...... 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...... accurately predict the steam reforming rate in a stack from the rate expression obtained from the packed bed experiments. During the experiments a previously unreported long term dynamic behavior of the catalyst was observed. After startup, the initial high reactivity was slowly reduced by a factor 5-10 over...

  19. 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.

  20. Heat Modeling and Material Development of Mg-Based Nanomaterials Combined with Solid Oxide Fuel Cell for Stationary Energy Storage

    Directory of Open Access Journals (Sweden)

    Huaiyu Shao

    2017-11-01

    Full Text Available Mg-based materials have been investigated as hydrogen storage materials, especially for possible onboard storage in fuel cell vehicles for decades. Recently, with the development of large-scale fuel cell technologies, the development of Mg-based materials as stationary storage to supply hydrogen to fuel-cell components and provide electricity and heat is becoming increasingly promising. In this work, numerical analysis of heat balance management for stationary solid oxide fuel cell (SOFC systems combined with MgH2 materials based on a carbon-neutral design concept was performed. Waste heat from the SOFC is supplied to hydrogen desorption as endothermic heat for the MgH2 materials. The net efficiency of this model achieves 82% lower heating value (LHV, and the efficiency of electrical power output becomes 68.6% in minimizing heat output per total energy output when all available heat of waste gas and system is supplied to warm up the storage. For the development of Mg-based hydrogen storage materials, various nano-processing techniques have been widely applied to synthesize Mg-based materials with small particle and crystallite sizes, resulting in good hydrogen storage kinetics, but poor thermal conductivity. Here, three kinds of Mg-based materials were investigated and compared: 325 mesh Mg powers, 300 nm Mg nanoparticles synthesized by hydrogen plasma metal reaction, and Mg50Co50 metastable alloy with body-centered cubic structure. Based on the overall performances of hydrogen capacity, absorption kinetics and thermal conductivity of the materials, the Mg nanoparticle sample by plasma synthesis is the most promising material for this potential application. The findings in this paper may shed light on a new energy conversion and utilization technology on MgH2-SOFC combined concept.

  1. Effects of a novel light-curable material on odontoblastic differentiation of human dental pulp cells.

    Science.gov (United States)

    Lee, B-N; Lee, B-G; Chang, H-S; Hwang, Y-C; Hwang, I-N; Oh, W-M

    2017-05-01

    To assess the biological effects, including odontoblastic differentiation of a novel light-curable material (TheraCal), on human dental pulp cells (hDPCs). The hDPCs were isolated from freshly extracted, caries-free third molars. Ten discs of TheraCal and MTA (8 mm in diameter and 3 mm in height) were incubated in α-minimum essential medium (α-MEM) and the supernatant collected. Viability of hDPCs in response to TheraCal and MTA was measured using the WST-1 assay. RT-PCR and real-time PCR were used to detect the gene expression of dentine sialophosphoprotein (DSPP) and dentine matrix protein-1 (DMP-1). ALP staining and Alizarin red S staining were used to evaluate the expression of alkaline phosphatase (ALP) and mineralization behaviour. One-way analysis of variance and Tukey's post hoc test were used to determine the statistically significant differences as a result of the variation in test materials (P TheraCal and MTA on cell viability were similar except at the highest concentration. The mRNA level of DSPP increased significantly in the MTA group relative to the control at day 1 and 3 (P TheraCal group relative to the control at day 3 (P TheraCal groups relative to the control (P TheraCal groups compared to the control (P TheraCal and MTA had the ability to induce odontoblastic differentiation and mineralization of hDPCs. © 2016 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  2. Multichannel Spectroscopic Ellipsometry for CdTe Photovoltaics: from Materials and Interfaces to Solar Cells

    Science.gov (United States)

    Koirala, Prakash

    growth. Information from RT-SE at a single point during solar cell stack deposition assists in the development of a model that has been used for mapping the properties of the completed cell stack, which can then be correlated with device performance. Independent non-uniformities in the layers over the full area of the cell stack enable optimization of cell performance combinatorially. The polycrystalline CdS/CdTe thin-film solar cell in the superstrate configuration has been studied by SE using glass side illumination whereby the single reflection from the glass/film-stack interface is collected whereas that from the ambient/glass interface and those from multiple glass/film-stack reflections are rejected. The SE data analysis applies an optical model consisting of a multilayer stack with bulk and interface layers. The dielectric functions epsilonfor the solar cell component materials were obtained by variable-angle and in-situ SE. Variability in the properties of the materials are introduced through free parameters in analytical expressions for the dielectric functions. In the SE analysis of the complete cell, a step-wise procedure ranks all free parameters of the model, including thicknesses and those defining the spectra in epsilon, according to their ability to reduce the root-mean-square deviation between simulated and measured SE spectra. The results for the best fit thicknesses compare well with electron microscopy. From the optical model, including all best-fit parameters, the solar cell quantum efficiency (QE) can be simulated without free parameters, and comparisons with QE measurements have enabled the identification of losses. The capabilities have wide applications in off-line photovoltaic module mapping and in-line monitoring of coated glass at intermediate stages of production. Mapping spectroscopic ellipsometry (M-SE) has been applied in this dissertation research as an optimization procedure for polycrystalline CdS/CdTe solar cell fabrication on TCO

  3. Silicon Derived from Glass Bottles as Anode Materials for Lithium Ion Full Cell Batteries.

    Science.gov (United States)

    Li, Changling; Liu, Chueh; Wang, Wei; Mutlu, Zafer; Bell, Jeffrey; Ahmed, Kazi; Ye, Rachel; Ozkan, Mihrimah; Ozkan, Cengiz S

    2017-04-19

    Every year many tons of waste glass end up in landfills without proper recycling, which aggravates the burden of waste disposal in landfill. The conversion from un-recycled glass to favorable materials is of great significance for sustainable strategies. Recently, silicon has been an exceptional anode material towards large-scale energy storage applications, due to its extraordinary lithiation capacity of 3579 mAh g -1 at ambient temperature. Compared with other quartz sources obtained from pre-leaching processes which apply toxic acids and high energy-consuming annealing, an interconnected silicon network is directly derived from glass bottles via magnesiothermic reduction. Carbon-coated glass derived-silicon (gSi@C) electrodes demonstrate excellent electrochemical performance with a capacity of ~1420 mAh g -1 at C/2 after 400 cycles. Full cells consisting of gSi@C anodes and LiCoO 2 cathodes are assembled and achieve good initial cycling stability with high energy density.

  4. Development of organic-inorganic double hole-transporting material for high performance perovskite solar cells

    Science.gov (United States)

    Jo, Jea Woong; Seo, Myung-Seok; Jung, Jae Woong; Park, Joon-Suh; Sohn, Byeong-Hyeok; Ko, Min Jae; Son, Hae Jung

    2018-02-01

    The control of the optoelectronic properties of the interlayers of perovskite solar cells (PSCs) is crucial for achieving high photovoltaic performances. Of the solution-processable interlayer candidates, NiOx is considered one of the best inorganic hole-transporting layer (HTL) materials. However, the power conversion efficiencies (PCEs) of NiOx-based PSCs are limited by the unfavorable contact between perovskite layers and NiOx HTLs, the high density of surface trap sites, and the inefficient charge extraction from perovskite photoactive layers to anodes. Here, we introduce a new organic-inorganic double HTL consisting of a Cu:NiOx thin film passivated by a conjugated polyelectrolyte (PhNa-1T) film. This double HTL has a significantly lower pinhole density and forms better contact with perovskite films, which results in enhanced charge extraction. As a result, the PCEs of PSCs fabricated with the double HTL are impressively improved up to 17.0%, which is more than 25% higher than that of the corresponding PSC with a Cu:NiOx HTL. Moreover, PSCs with the double HTLs exhibit similar stabilities under ambient conditions to devices using inorganic Cu:NiOx. Therefore, this organic-inorganic double HTL is a promising interlayer material for high performance PSCs with high air stability.

  5. Study of optimization options for second generation solar cell materials by multilevel modeling

    Directory of Open Access Journals (Sweden)

    Dmitry N. Krasikov

    2016-09-01

    Full Text Available Theoretical analysis of optimization options for the properties of CdTe absorber layer is an important task for increasing the efficiency of CdTe/CdS heterojunction based thin-film solar cells. Properties of the materials (e.g. the density of free carriers often depend essentially on the parameters of the deposition process and subsequent treatment which determine the defect composition of the material. In this work a model based on the lattice kinetic Monte-Carlo method is developed to describe the process of CdTe deposition as a function of temperature and Cd and Te fluxes. To determine the effect of the treatment conditions on CdTe conductivity, we developed a quasichemical model based on the electrical neutrality equation for point defect concentrations that are described by defect formation reaction constants. Parameters obtained from the first-principles density functional calculations were used for developing the models. The developed deposition model correctly describes the transition from evaporation to precipitation as well as the increased evaporation rates in excess of Cd. To explain the observed electrical properties of CdTe after Cl-treatment, we complemented the quasichemical defect model by a deep acceptor complex defect that allowed us to describe both the high-temperature dependence of conductivity on the Cd pressure and the dependence of resistivity on Cl concentration at room temperature.

  6. Simultaneous characterization of protein-material and cell-protein interactions using dynamic QCM-D analysis on SAM surfaces.

    Science.gov (United States)

    Kushiro, Keiichiro; Lee, Chih-Hao; Takai, Madoka

    2016-05-24

    Understanding the interactions among materials, proteins and cells is critical for the development of novel biomaterials, and establishing a highly sensitive and quantitative method to standardize these interactions is desired. In this study, quartz crystal microbalance with dissipation (QCM-D) combined with microscopy was utilized to quantitatively monitor the entirety of the cell adhesion processes, starting from the protein adsorption, on various self-assembled monolayer (SAM) surfaces. Although the resulting cell adhesion morphologies were similar on most of the surfaces, the dynamic QCM-D signal patterns were unique on each surface, suggesting different forms of material-protein-cell interactions. The viscoelasticity and the density of the surface-adsorbed fibronectin (FN), as well as the relative exposure of the cell adhesive arginine-glycine-aspartic acid (RGD) motifs, were correlated to the different cell adhesion dynamics and mechanics. Some surfaces exhibited complicated behaviors alluding to the detachment/rearrangement of surface proteins or highly sparse but bioactive proteins that promote a slow adhesion process. This study underscores the potential use of the QCM-D signal pattern as a rule of thumb for delineating different protein-material and cell-protein interactions, and offers a rapid in vitro platform for the dynamic evaluation of protein and cell behaviors on novel biomaterials.

  7. Commercial materials as cathode for hydrogen production in microbial electrolysis cell.

    Science.gov (United States)

    Farhangi, Sara; Ebrahimi, Sirous; Niasar, Mojtaba Shariati

    2014-10-01

    The use of commercial electrodes as cathodes in a single-chamber microbial electrolysis cell has been investigated. The cell was operated in sequencing batch mode and the performance of the electrodes was compared with carbon cloth containing 0.5 mg Pt cm(-2). Overall H2 recovery [Formula: see text] was 66.7 ± 1.4, 58.7 ± 1.1 and 55.5 ± 1.5 % for Pt/CC, Ni and Ti mesh electrodes, respectively. Columbic efficiencies of the three cathodes were in the same range (74.8 ± 1.5, 77.6 ± 1.7 and 75.7 ± 1.2 % for Pt/CC, Ni and Ti mesh electrodes, respectively). A similar performance for the three cathodes under near-neutral pH and ambient temperature was obtained. The commercial electrodes are much cheaper than carbon cloth containing Pt. Low cost and good performance of these electrodes suggest they are suitable cathode materials for large scale application.

  8. Characterizing automotive fuel cell materials by soft x-ray scanning transmission x-ray microscopy

    International Nuclear Information System (INIS)

    Hitchcock, A. P.; Lee, V.; Wu, J.; Cooper, G.; West, M. M.; 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

  9. A new structure for comparing surface passivation materials of GaAs solar cells

    Science.gov (United States)

    Desalvo, Gregory C.; Barnett, Allen M.

    1989-01-01

    The surface recombination velocity (S sub rec) for bare GaAs is typically as high as 10 to the 6th power to 10 to the 7th power cm/sec, which dramatically lowers the efficiency of GaAs solar cells. Early attempts to circumvent this problem by making an ultra thin junction (xj less than .1 micron) proved unsuccessful when compared to lowering S sub rec by surface passivation. Present day GaAs solar cells use an GaAlAs window layer to passivate the top surface. The advantages of GaAlAs in surface passivation are its high bandgap energy and lattice matching to GaAs. Although GaAlAs is successful in reducing the surface recombination velocity, it has other inherent problems of chemical instability (Al readily oxidizes) and ohmic contact formation. The search for new, more stable window layer materials requires a means to compare their surface passivation ability. Therefore, a device structure is needed to easily test the performance of different passivating candidates. Such a test device is described.

  10. Replacement of Biphenyl by Bipyridine Enabling Powerful Hole Transport Materials for Efficient Perovskite Solar Cells.

    Science.gov (United States)

    Wu, Fei; Shan, Yahan; Qiao, Jianhui; Zhong, Cheng; Wang, Rui; Song, Qunliang; Zhu, Linna

    2017-10-09

    Here, 2,2'- and 3,3'-bipyridine are introduced for the first time as the core structure to get two new hole transport materials (HTMs), namely F22 and F33. The electron-withdrawing nature of bipyridine lowers the HOMO level of the new compounds and enhances the open-circuit voltage of perovskite solar cells. Especially for F33, the better planarity leads to better conjugation in the whole molecule and the molecular interaction is enhanced. Hole-mobility tests, steady-state photoluminescence (PL) spectra as well as time-resolved PL decay results demonstrate that the new HTMs exhibit good hole extraction and hole-transporting property. Impressive power conversion efficiencies of 17.71 and 18.48 % are achieved in conventional planar perovskite (CH 3 NH 3 PbI 3-x Cl x ) solar cells containing F22 and F33 as HTMs, respectively. As far as we know, this is the first report on bypiridine-based HTMs with leading efficiencies, and the design motif in this work opens a new way for devising HTMs in the future. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. A low cost and high performance polymer donor material for polymer solar cells.

    Science.gov (United States)

    Sun, Chenkai; Pan, Fei; Bin, Haijun; Zhang, Jianqi; Xue, Lingwei; Qiu, Beibei; Wei, Zhixiang; Zhang, Zhi-Guo; Li, Yongfang

    2018-02-21

    The application of polymer solar cells requires the realization of high efficiency, high stability, and low cost devices. Here we demonstrate a low-cost polymer donor poly[(thiophene)-alt-(6,7-difluoro-2-(2-hexyldecyloxy)quinoxaline)] (PTQ10), which is synthesized with high overall yield of 87.4% via only two-step reactions from cheap raw materials. More importantly, an impressive efficiency of 12.70% is obtained for the devices with PTQ10 as donor, and the efficiency of the inverted structured PTQ10-based device also reaches 12.13% (certificated to be 12.0%). Furthermore, the as-cast devices also demonstrate a high efficiency of 10.41% and the devices exhibit insensitivity of active layer thickness from 100 nm to 300 nm, which is conductive to the large area fabrication of the devices. In considering the advantages of low cost and high efficiency with thickness insensitivity, we believe that PTQ10 will be a promising polymer donor for commercial application of polymer solar cells.

  12. Slow-muon study of quaternary solar-cell materials: Single layers and p -n junctions

    Science.gov (United States)

    Alberto, H. V.; Vilão, R. C.; Vieira, R. B. L.; Gil, J. M.; Weidinger, A.; Sousa, M. G.; Teixeira, J. P.; da Cunha, A. F.; Leitão, J. P.; Salomé, P. M. P.; Fernandes, P. A.; Törndahl, T.; Prokscha, T.; Suter, A.; Salman, Z.

    2018-02-01

    Thin films and p -n junctions for solar cells based on the absorber materials Cu (In ,G a ) Se2 and Cu2ZnSnS4 were investigated as a function of depth using implanted low energy muons. The most significant result is a clear decrease of the formation probability of the Mu+ state at the heterojunction interface as well as at the surface of the Cu (In ,G a ) Se2 film. This reduction is attributed to a reduced bonding reaction of the muon in the absorber defect layer at its surface. In addition, the activation energies for the conversion from a muon in an atomiclike configuration to a anion-bound position are determined from temperature-dependence measurements. It is concluded that the muon probe provides a measurement of the effective surface defect layer width, both at the heterojunctions and at the films. The CIGS surface defect layer is crucial for solar-cell electrical performance and additional information can be used for further optimizations of the surface.

  13. Advanced materials for solid oxide fuel cells: Hafnium-Praseodymium-Indium Oxide System

    Energy Technology Data Exchange (ETDEWEB)

    Bates, J.L.; Griffin, C.W.; Weber, W.J.

    1988-06-01

    The HfO/sub 2/-PrO/sub 1.83/-In/sub 2/O/sub 3/ system has been studied at the Pacific Northwest Laboratory to develop alternative, highly electrically conducting oxides as electrode and interconnection materials for solid oxide fuel cells. A coprecipitation process was developed for synthesizing single-phase, mixed oxide powders necessary to fabricate powders and dense oxides. A ternary phase diagram was developed, and the phases and structures were related to electrical transport properties. Two new phases, an orthorhombic PrInO/sub 3/ and a rhombohedral Hf/sub 2/In/sub 2/O/sub 7/ phase, were identified. The highest electronic conductivity is related to the presence of a bcc, In/sub 2/O/sub 3/ solid solution (ss) containing HfO/sub 2/ and PrO/sub 1.83/. Compositions containing more than 35 mol % of the In/sub 2/O/sub 3/ ss have electrical conductivities greater than 10/sup /minus/1/ (ohm-cm)/sup /minus/1/, and the two or three phase structures that contain this phase appear to exhibit mixed electronic-ionic conduction. The high electrical conductivities and structures similar to the Y/sub 2/O/sub 3/-stabilized ZrO/sub 2/(HfO/sub 2/) electrolyte give these oxides potential for use as cathodes in solid oxide fuel cells. 21 refs.

  14. Appropriate materials and preparation techniques for polycrystalline-thin-film thermophotovoltaic cells

    Science.gov (United States)

    Dhere, Neelkanth G.

    1997-03-01

    Polycrystalline-thin-film thermophotovoltaic (TPV) cells have excellent potential for reducing the cost of TPV generators so as to address the hitherto inaccessible and highly competitive markets such as self-powered gas-fired residential warm air furnaces and energy-efficient electric cars, etc. Recent progress in polycrystalline-thin-film solar cells have made it possible to satisfy the diffusion length and intrinsic junction rectification criteria for TPV cells operating at high fluences. Continuous ranges of direct bandgaps of the ternary and pseudoternary compounds such as Hg1-xCdxTe, Pb1-xCdxTe, Hg1-xZnxTe, and Pb1-xZnxS cover the region of interest of 0.50-0.75 eV for efficient TPV conversion. Other ternary and pseudoternary compounds which show direct bandgaps in most of or all of the 0.50-0.75 eV range are Pb1-xZnxTe, Sn1-xCd2xTe2, Pb1-xCdxSe, Pb1-xZnxSe, and Pb1-xCdxS. Hg1-xCdxTe (with x~0.21) has been studied extensively for infrared detectors. PbTe and Pb1-xSnxTe have also been studied for infrared detectors. Not much work has been carried out on Hg1-xZnxTe thin films. Hg1-xCdxTe and Pb1-xCdxTe alloys cover a wide range of cut-off wavelengths from the far infrared to the near visible. Acceptors and donors are introduced in these materials by excess non-metal (Te) and excess metal (Hg and Pb) respectively. Extrinsic acceptor impurities are Cu, Au, and As while and In and Al are donor impurities. Hg1-xCdxTe thin films have been deposited by isothermal vapor-phase epitaxy (VPE), liquid phase epitaxy (LPE), hot-wall metalorganic chemical vapor deposition (MOCVD), electrodeposition, sputtering, molecular beam epitaxy (MBE), laser-assisted evaporation, and vacuum evaporation with or without hot-wall enclosure. The challenge in the preparation of Hg1-xCdxTe is to provide excess mercury incidence rate, to optimize the deposition parameters for enhanced mercury incorporation, and to achieve the requisite stoichiometry, grain size, and doping. MBE and MOCVD

  15. Effect of gonadotrophin inhibiting material isolated from human urine on action of prolactin at rat Leydig cell

    International Nuclear Information System (INIS)

    Bagli, N.P.; Rajendran, K.G.; Shah, P.N.

    1980-01-01

    To study the effect of g.onadotrophin inhibiting material (GIM) on the binding of prolactin to Leydig cell receptors isolated Leydig cells were incubated with sup(125)I-prolactin. Presence of GIM in the incubation mixture did not inhibit the binding of sup(125)I-prolactin to Leydig cells whereas unlabelled prolactin significantly reduced the binding. In another experiment, testicular cells were incubated with FITC-tagged GIM. Binding of GIM to Leydig cells was seen by the presence of fluorescence on these cells. This binding could be inhibited by untagged GIM but not by prolactin. The results suggest the presence of separate receptors for GIM and prolactin on the Leydig cells and indicate that termination of pregnancy by GIM is not due to any interference with prolactin binding to its receptors. (auth.)

  16. Tenth Workshop on Crystalline Silicon Solar Cell Materials and Processes: A Summary of Discussion Sessions

    Energy Technology Data Exchange (ETDEWEB)

    Tan, T.; Swanson, D.; Sinton, R.; Sopori, B.

    2001-01-22

    The 10th Workshop on Silicon Solar Cell Materials and Processes was held in Copper Mountain, Colorado, on August 13-16, 2000. The workshop was attended by 85 scientists and engineers from 15 international photovoltaic (PV) companies and 24 research institutions. Review and poster presentations were augmented by discussion sessions to address the recent progress and critical issues in meeting the goals for Si in the PV Industry Roadmap. The theme of the workshop was Si Photovoltaics: 10 Years of Progress and Opportunities for the Future. Two special sessions were held: Advanced Metallization and Interconnections - covering recent advances in solar cell metallization, printed contacts and interconnections, and addressing new metallization schemes for low-cost cell interconnections; and Characterization Methods - addressing the growing need for process monitoring techniques in the PV industry. The following major issues emerged from the discussion sessions: (1) Mechanical breakage in the P V industry involves a large fraction, about 5%-10%, of the wafers. (2) The current use of Al screen-printed back-contacts appears to be incompatible with the PV Industry Roadmap requirements. (3) The PV manufacturers who use hydrogen passivation should incorporate the plasma-enhanced chemical vapor deposited (PECVD) nitride for antireflection coating and hydrogenation. (4) There is an imminent need to dissolve metallic precipitates to minimize the electrical shunt problem caused by the ''bad'' regions in wafers. (5) Industry needs equipment for automated, in-line monitoring and testing. There are simply not many tools available to industry. (6) In the Wrap-Up Session of the workshop, there was consensus to create four industry/university teams that would address critical research topics in crystalline silicon. (7) The workshop attendees unanimously agreed that the workshop has served well the PV community by promoting the fundamental understanding of industrial

  17. 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

  18. 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...... Strategic Energy Technology Plan. The report summarises the results, including key targets identified for medium term (2020/2030) and long term (2050) timescales....

  19. Chondrogenesis of human bone marrow mesenchymal stem cells in 3-dimensional, photocrosslinked hydrogel constructs: Effect of cell seeding density and material stiffness.

    Science.gov (United States)

    Sun, Aaron X; Lin, Hang; Fritch, Madalyn R; Shen, He; Alexander, Pete G; DeHart, Michael; Tuan, Rocky S

    2017-08-01

    Three-dimensional hydrogel constructs incorporated with live stem cells that support chondrogenic differentiation and maintenance offer a promising regenerative route towards addressing the limited self-repair capabilities of articular cartilage. In particular, hydrogel scaffolds that augment chondrogenesis and recapitulate the native physical properties of cartilage, such as compressive strength, can potentially be applied in point-of-care procedures. We report here the synthesis of two new materials, [poly-l-lactic acid/polyethylene glycol/poly-l-lactic acid] (PLLA-PEG 1000) and [poly-d,l-lactic acid/polyethylene glycol/poly-d,l-lactic acid] (PDLLA-PEG 1000), that are biodegradable, biocompatible (>80% viability post fabrication), and possess high, physiologically relevant mechanical strength (∼1500 to 1800kPa). This study examined the effects of physiologically relevant cell densities (4, 8, 20, and 50×10 6 /mL) and hydrogel stiffnesses (∼150kPa to∼1500kPa Young's moduli) on chondrogenesis of human bone marrow stem cells incorporated in hydrogel constructs fabricated with these materials and a previously characterized PDLLA-PEG 4000. Results showed that 20×10 6 cells/mL, under a static culture condition, was the most efficient cell seeding density for extracellular matrix (ECM) production on the basis of hydroxyproline and glycosaminoglycan content. Interestingly, material stiffness did not significantly affect chondrogenesis, but rather material concentration was correlated to chondrogenesis with increasing levels at lower concentrations based on ECM production, chondrogenic gene expression, and histological analysis. These findings establish optimal cell densities for chondrogenesis within three-dimensional cell-incorporated hydrogels, inform hydrogel material development for cartilage tissue engineering, and demonstrate the efficacy and potential utility of PDLLA-PEG 1000 for point-of-care treatment of cartilage defects. Engineering cartilage with

  20. 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.

  1. DNA polymeric films as a support for cell growth as a new material for regenerative medicine: Compatibility and applicability.

    Science.gov (United States)

    Jayme, Cristiano Ceron; de Paula, Leonardo Barcelos; Rezende, Nayara; Calori, Italo Rodrigo; Franchi, Leonardo Pereira; Tedesco, Antonio Claudio

    2017-11-15

    DNA polymeric films (DNA-PFs) are a promising drug delivery system (DDS) in modern medicine. In this study, we evaluated the growth behavior of oral squamous cell carcinoma (OSCC) cells on DNA-PFs. The morphological, biochemical, and cytometric features of OSCC cell adhesion on DNA-PFs were also assessed. An initial, temporary alteration in cell morphology was observed at early time points owing to the inhibition of cell attachment to the film, which then returned to a normal morphological state at later time points. MTT and resazurin assays showed a moderate reduction in cell viability related to increased DNA concentration in the DNA-PFs. Flow cytometry studies showed low cytotoxicity of DNA-PFs, with cell viabilities higher than 90% in all the DNA-PFs tested. Flow cytometric cell cycle analysis also showed average cell cycle phase distributions at later time points, indicating that OSCC cell growth is maintained in the presence of DNA-PFs. These results show high biocompatibility of DNA-PFs and suggest their use in designing "dressing material," where the DNA film acts as a support for cell growth, or with incorporation of active or photoactive compounds, which can induce tissue regeneration and are useful to treat many diseases, especially oral cancer. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. 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.

  3. 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.

  4. 3D-Printed pHEMA Materials for Topographical and Biochemical Modulation of Dorsal Root Ganglion Cell Response.

    Science.gov (United States)

    Badea, Adina; McCracken, Joselle M; Tillmaand, Emily G; Kandel, Mikhail E; Oraham, Aaron W; Mevis, Molly B; Rubakhin, Stanislav S; Popescu, Gabriel; Sweedler, Jonathan V; Nuzzo, Ralph G

    2017-09-13

    Understanding and controlling the interactions occurring between cells and engineered materials are central challenges toward progress in the development of biomedical devices. In this work, we describe materials for direct ink writing (DIW), an extrusion-based type of 3D printing, that embed a custom synthetic protein (RGD-PDL) within the microfilaments of 3D-hydrogel scaffolds to modify these interactions and differentially direct tissue-level organization of complex cell populations in vitro. The RGD-PDL is synthesized by modifying poly-d-lysine (PDL) to varying extents with peptides containing the integrin-binding motif Arg-Gly-Asp (RGD). Compositional gradients of the RGD-PDL presented by both patterned and thin-film poly(2-hydroxyethyl) methacrylate (pHEMA) substrates allow the patterning of cell-growth compliance in a grayscale form. The surface chemistry-dependent guidance of cell growth on the RGD-PDL-modified pHEMA materials is demonstrated using a model NIH-3T3 fibroblast cell line. The formation of a more complex cellular system-organotypic primary murine dorsal root ganglion (DRG)-in culture is also achieved on these scaffolds, where distinctive forms of cell growth and migration guidance are seen depending on their RGD-PDL content and topography. This experimental platform for the study of physicochemical factors on the formation and the reorganization of organotypic cultures offers useful capabilities for studies in tissue engineering, regenerative medicine, and diagnostics.

  5. The comparison between gallium arsenide and indium gallium arsenide as materials for solar cell performance using Silvaco application

    International Nuclear Information System (INIS)

    Zahari, Suhaila Mohd; Norizan, Mohd Natashah; Mohamad, Ili Salwani; Osman, Rozana Aina Maulat; Taking, Sanna

    2015-01-01

    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 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

  6. 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.

  7. The comparison between gallium arsenide and indium gallium arsenide as materials for solar cell performance using Silvaco application

    Science.gov (United States)

    Zahari, Suhaila Mohd; Norizan, Mohd Natashah; Mohamad, Ili Salwani; Osman, Rozana Aina Maulat; Taking, Sanna

    2015-05-01

    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, Pmax 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. 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

  9. Amino acid derivative-mediated detoxification and functionalization of dual cure dental restorative material for dental pulp cell mineralization.

    Science.gov (United States)

    Minamikawa, Hajime; Yamada, Masahiro; Iwasa, Fuminori; Ueno, Takeshi; Deyama, Yoshiaki; Suzuki, Kuniaki; Yawaka, Yasutaka; Ogawa, Takahiro

    2010-10-01

    Current dental restorative materials are only used to fill the defect of hard tissues, such as dentin and enamel, because of their cytotoxicity. Therefore, exposed dental pulp tissues in deep cavities must be first covered by a pulp capping material like calcium hydroxide to form a layer of mineralized tissue. However, this tissue mineralization is based on pathological reaction and triggers long-lasting inflammation, often causing clinical problems. This study tested the ability of N-acetyl cysteine (NAC), amino acid derivative, to reduce cytotoxicity and induce mineralized tissue conductivity in resin-modified glass ionomer (RMGI), a widely used dental restorative material having dual cure mechanism. Rat dental pulp cells were cultured on untreated or NAC-supplemented RMGI. NAC supplementation substantially increased the percentage of viable cells from 46.7 to 73.3% after 24-h incubation. Cell attachment, spreading, proliferative activity, and odontoblast-related gene and protein expressions increased significantly on NAC-supplemented RMGI. The mineralization capability of cells, which was nearly suppressed on untreated RMGI, was induced on NAC-supplemented RMGI. These improved behaviors and functions of dental pulp cells on NAC-supplemented RMGI were associated with a considerable reduction in the production of intracellular reactive oxygen species and with the increased level of intracellular glutathione reserves. These results demonstrated that NAC could detoxify and functionalize RMGIs via two different mechanisms involving in situ material detoxification and antioxidant cell protection. We believe that this study provides a new approach for developing dental restorative materials that enables mineralized tissue regeneration.

  10. Thermal expansion coefficient prediction of fuel-cell seal materials from silica sand

    Science.gov (United States)

    Hidayat, Nurul; Triwikantoro, Baqiya, Malik A.; Pratapa, Suminar

    2013-09-01

    This study is focused on the prediction of coefficient of thermal expansion (CTE) of silica-sand-based fuel-cell seal materials (FcSMs) which in principle require a CTE value in the range of 9.5-12 ppm/°C. A semi-quantitative theoretical method to predict the CTE value is proposed by applying the analyzed phase compositions from XRD data and characterized density-porosity behavior. A typical silica sand was milled at 150 rpm for 1 hour followed by heating at 1000 °C for another hour. The sand and heated samples were characterized by means of XRD to perceive the phase composition correlation between them. Rietveld refinement was executed to investigate the weight fraction of the phase contained in the samples, and then converted to volume fraction for composite CTE calculations. The result was applied to predict their potential physical properties for FcSM. Porosity was taken into account in the calculation after which it was directly measured by the Archimedes method.

  11. 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.

  12. Unsymmetrical triphenylamine-oligothiophene hybrid conjugated systems as donor materials for high-voltage solution-processed organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Ripaud, Emilie; Rousseau, Theodulf; Leriche, Philippe; Roncali, Jean [Group Linear Conjugated Systems, CNRS Moltech-Anjou, University of Angers, 2Bd Lavoisier, 49045 Angers (France)

    2011-07-15

    The synthesis of unsymmetrical triphenylamine-oligothiophene hybrid conjugated systems bearing dicyanovinyl electron acceptor end-groups is presented. When used as molecular donor materials in solution-processed bulk heteroj-unction solar cells, these compounds lead to efficient devices with very high open-circuit voltages. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Evaluation of Novel Semiconductor Materials Potentially Useful in Solar Cells: Cooperative Research and Development Final Report, CRADA number CRD-06-00172

    Energy Technology Data Exchange (ETDEWEB)

    Geisz, J.

    2010-07-01

    Evaluation of novel semiconductor materials potentially useful in solar cells. NREL will fabricate, test and analyze solar cells from EpiWorks' wafers produced in 2-3 separate growth campaigns. NREL will also characterize material from 2-3 separate EpiWorks material development campaigns. Finally, NREL will visit EpiWorks and help establish any necessary process, such as spectral CV measurements and III-V on Si metalization processes and help validate solar cell designs and performance.

  14. Material Science for High-Efficiency Photovoltaics: From Advanced Optical Coatings to Cell Design for High-Temperature Applications

    Science.gov (United States)

    Perl, Emmett Edward

    Solar cells based on III-V compound semiconductors are ideally suited to convert solar energy into electricity. The highest efficiency single-junction solar cells are made of gallium arsenide, and have attained an efficiency of 28.8%. Multiple III-V materials can be combined to construct multijunction solar cells, which have reached record efficiencies greater than 45% under concentration. III-V solar cells are also well suited to operate efficiently at elevated temperatures, due in large part to their high material quality. These properties make III-V solar cells an excellent choice for use in concentrator systems. Concentrator photovoltaic systems have attained module efficiencies that exceed 40%, and have the potential to reach the lowest levelized cost of electricity in sunny places like the desert southwest. Hybrid photovoltaic-thermal solar energy systems can utilize high-temperature III-V solar cells to simultaneously achieve dispatchability and a high sunlight-to-electricity efficiency. This dissertation explores material science to advance the state of III-V multijunction solar cells for use in concentrator photovoltaic and hybrid photovoltaic-thermal solar energy systems. The first half of this dissertation describes work on advanced optical designs to improve the efficiency of multijunction solar cells. As multijunction solar cells move to configurations with four or more subcells, they utilize a larger portion of the solar spectrum. Broadband antireflection coatings are essential to realizing efficiency gains for these state-of-the-art cells. A hybrid design consisting of antireflective nanostructures placed on top of multilayer interference-based optical coatings is developed. Antireflection coatings that utilize this hybrid approach yield unparalleled performance, minimizing reflection losses to just 0.2% on sapphire and 0.6% on gallium nitride for 300-1800nm light. Dichroic mirrors are developed for bonded 5-junction solar cells that utilize InGaN as

  15. 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.

  16. Bone substitute material composition and morphology differentially modulate calcium and phosphate release through osteoclast-like cells.

    Science.gov (United States)

    Konermann, A; Staubwasser, M; Dirk, C; Keilig, L; Bourauel, C; Götz, W; Jäger, A; Reichert, C

    2014-04-01

    The aim of this study was to determine the material composition and cell-mediated remodelling of different calcium phosphate-based bone substitutes. Osteoclasts were cultivated on bone substitutes (Cerabone, Maxresorb, and NanoBone) for up to 5 days. Bafilomycin A1 addition served as the control. To determine cellular activity, the supernatant content of calcium and phosphate was measured by inductively coupled plasma optical emission spectrometry. Cells were visualized on the materials by scanning electron microscopy. Material composition and surface characteristics were assessed by energy-dispersive X-ray spectroscopy. Osteoclast-induced calcium and phosphate release was material-specific. Maxresorb exhibited the highest ion release to the medium (P = 0.034; calcium 40.25mg/l day 5, phosphate 102.08 mg/l day 5) and NanoBone the lowest (P = 0.021; calcium 8.43 mg/l day 5, phosphate 15.15 mg/l day 5); Cerabone was intermediate (P = 0.034; calcium 16.34 mg/l day 5, phosphate 30.6 mg/l day 5). All investigated materials showed unique resorption behaviours. The presented methodology provides a new perspective on the investigation of bone substitute biodegradation, maintaining the material-specific micro- and macrostructure. Copyright © 2013 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  17. THE DEVELOPMENT OF AIR-THEME INTEGRATED SCIENCE TEACHING MATERIAL USING FOUR STEPS TEACHING MATERIAL DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    A. Arifin

    2016-01-01

    Full Text Available The purposes of this study are to develop, to test the feasibility, to describe the characteristic, and to test the students understanding about integrated science teaching material about air using Four Steps Teaching Material Development (4S TMD. The Research and Development method was use to develop integrated science teaching materials which is involving  all science perspectives that are not presented in junior high school science book. The air theme was chosen in this study since it can be explained using biology, chemistry, physics, and earth and space science  perspectives. Development the teaching materials was consists of selection, structuring, characterization, and reduction didactic steps. Based on the of feasibility test results, the teaching material is qualified in content, presentation, language, and graphic feasibility aspects. The characteristic of this teaching material expose the closeness theme with student daily lifes and its compatibility with National Books Standard. Based on the understanding test results, the teaching material is qualified in understanding aspect with high category. It can be concluded that the teaching material qualified to be used as supplement teaching material of science learning.Penelitian ini bertujuan untuk mengembangkan, menguji kelayakan, memaparkan karakteristik, dan menguji keterpahaman bahan ajar IPA terpadu pada tema udara untuk siswa SMP kelas VII melalui Four Steps Teaching Material Development (4S TMD. Penelitian dengan metode Research and Development (R&D ini dilatar belakangi oleh tidak tersedianya bahan ajar IPA SMP yang disajikan secara terpadu melalui tema udara. Pengembangan bahan ajar IPA terpadu tema udara terdiri dari tahap seleksi, strukturisasi, karakterisasi dan reduksi didaktik. Berdasarkan uji kelayakan, bahan ajar telah memenuhi aspek kelayakan isi, kelayakan penyajian, kelayakan bahasa dan kelayakan kegrafikan. Karakteristik bahan ajar meliputi kedekatan tema bahan ajar

  18. Supercritical CO2 foaming of thermoplastic materials derived from maize: proof-of-concept use in mammalian cell culture applications.

    Directory of Open Access Journals (Sweden)

    Grissel Trujillo-de Santiago

    Full Text Available Foams are high porosity and low density materials. In nature, they are a common architecture. Some of their relevant technological applications include heat and sound insulation, lightweight materials, and tissue engineering scaffolds. Foams derived from natural polymers are particularly attractive for tissue culture due to their biodegradability and bio-compatibility. Here, the foaming potential of an extensive list of materials was assayed, including slabs elaborated from whole flour, the starch component only, or the protein fraction only of maize seeds.We used supercritical CO2 to produce foams from thermoplasticized maize derived materials. Polyethylene-glycol, sorbitol/glycerol, or urea/formamide were used as plasticizers. We report expansion ratios, porosities, average pore sizes, pore morphologies, and pore size distributions for these materials. High porosity foams were obtained from zein thermoplasticized with polyethylene glycol, and from starch thermoplasticized with urea/formamide. Zein foams had a higher porosity than starch foams (88% and 85%, respectively and a narrower and more evenly distributed pore size. Starch foams exhibited a wider span of pore sizes and a larger average pore size than zein (208.84 vs. 55.43 μm2, respectively. Proof-of-concept cell culture experiments confirmed that mouse fibroblasts (NIH 3T3 and two different prostate cancer cell lines (22RV1, DU145 attached to and proliferated on zein foams.We conducted screening and proof-of-concept experiments on the fabrication of foams from cereal-based bioplastics. We propose that a key indicator of foamability is the strain at break of the materials to be foamed (as calculated from stress vs. strain rate curves. Zein foams exhibit attractive properties (average pore size, pore size distribution, and porosity for cell culture applications; we were able to establish and sustain mammalian cell cultures on zein foams for extended time periods.

  19. Poly(ethylene glycol)-[60]Fullerene-Based Materials for Perovskite Solar Cells with Improved Moisture Resistance and Reduced Hysteresis.

    Science.gov (United States)

    Collavini, Silvia; Saliba, Michael; Tress, Wolfgang R; Holzhey, Philippe J; Völker, Sebastian F; Domanski, Konrad; Turren-Cruz, Silver H; Ummadisingu, Amita; Zakeeruddin, Shaik M; Hagfeldt, Anders; Grätzel, Michael; Delgado, Juan L

    2018-03-22

    A series of [60]fullerenes covalently functionalized with the polymer poly(ethylene glycol) is presented. These new [60]fullerene-based materials have been incorporated as additives in CH 3 NH 3 PbI 3 (MAPbI 3 ), the most common organic-inorganic perovskite used in perovskite solar cells. The extensive photovoltaic study performed by using these materials shows several beneficial effects on the performance of these cells, including a reduction in hysteresis and an increased stability against moisture, whereby the solar cells retain up to 97 % of their initial power conversion efficiency in an ambient atmosphere. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Silicon materials task of the Low Cost Solar Array Project: Effect of impurities and processing on silicon solar cells

    Science.gov (United States)

    Hopkins, R. H.; Davis, J. R.; Rohatgi, A.; Hanes, M. H.; Rai-Choudhury, P.; Mollenkopf, H. C.

    1982-01-01

    The effects of impurities and processing on the characteristics of silicon and terrestrial silicon solar cells were defined in order to develop cost benefit relationships for the use of cheaper, less pure solar grades of silicon. The amount of concentrations of commonly encountered impurities that can be tolerated in typical p or n base solar cells was established, then a preliminary analytical model from which the cell performance could be projected depending on the kinds and amounts of contaminants in the silicon base material was developed. The impurity data base was expanded to include construction materials, and the impurity performace model was refined to account for additional effects such as base resistivity, grain boundary interactions, thermal processing, synergic behavior, and nonuniform impurity distributions. A preliminary assessment of long term (aging) behavior of impurities was also undertaken.

  1. Ab initio study of perovskite type oxide materials for solid oxide fuel cells

    Science.gov (United States)

    Lee, Yueh-Lin

    2011-12-01

    Perovskite type oxides form a family of materials of significant interest for cathodes and electrolytes of solid oxide fuel cells (SOFCs). These perovskites not only are active catalysts for surface oxygen reduction (OR) reactions but also allow incorporating the spilt oxygen monomers into their bulk, an unusual and poorly understood catalytic mechanism that couples surface and bulk properties. The OR mechanisms can be influenced strongly by defects in perovskite oxides, composition, and surface defect structures. This thesis work initiates a first step in developing a general strategy based on first-principles calculations for detailed control of oxygen vacancy content, transport rates of surface and bulk oxygen species, and surface/interfacial reaction kinetics. Ab initio density functional theory methods are used to model properties relevant for the OR reactions on SOFC cathodes. Three main research thrusts, which focus on bulk defect chemistry, surface defect structures and surface energetics, and surface catalytic properties, are carried to investigate different level of material chemistry for improved understanding of key physics/factors that govern SOFC cathode OR activity. In the study of bulk defect chemistry, an ab initio based defect model is developed for modeling defect chemistry of LaMnO 3 under SOFC conditions. The model suggests an important role for defect interactions, which are typically excluded in previous defect models. In the study of surface defect structures and surface energetics, it is shown that defect energies change dramatically (1˜2 eV lower) from bulk values near surfaces. Based on the existing bulk defect model with the calculated ab initio surface defect energetics, we predict the (001) MnO 2 surface oxygen vacancy concentration of (La0.9Sr0.1 )MnO3 is about 5˜6 order magnitude higher than that of the bulk under typical SOFC conditions. Finally, for surface catalytic properties, we show that area specific resistance, oxygen

  2. 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

  3. 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.

  4. 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

  5. Towards Cost-Effective Crystalline Silicon Based Flexible Solar Cells: Integration Strategy by Rational Design of Materials, Process, and Devices

    KAUST Repository

    Bahabry, Rabab R.

    2017-11-30

    The solar cells market has an annual growth of more than 30 percent over the past 15 years. At the same time, the cost of the solar modules diminished to meet both of the rapid global demand and the technological improvements. In particular for the crystalline silicon solar cells, the workhorse of this technology. The objective of this doctoral thesis is enhancing the efficiency of c-Si solar cells while exploring the cost reduction via innovative techniques. Contact metallization and ultra-flexible wafer based c-Si solar cells are the main areas under investigation. First, Silicon-based solar cells typically utilize screen printed Silver (Ag) metal contacts which affect the optimal electrical performance. To date, metal silicide-based ohmic contacts are occasionally used for the front contact grid lines. In this work, investigation of the microstructure and the electrical characteristics of nickel monosilicide (NiSi) ohmic contacts on the rear side of c-Si solar cells has been carried out. Significant enhancement in the fill factor leading to increasing the total power conversion efficiency is observed. Second, advanced classes of modern application require a new generation of versatile solar cells showcasing extreme mechanical resilience. However, silicon is a brittle material with a fracture strains <1%. Highly flexible Si-based solar cells are available in the form thin films which seem to be disadvantageous over thick Si solar cells due to the reduction of the optical absorption with less active Si material. Here, a complementary metal oxide semiconductor (CMOS) technology based integration strategy is designed where corrugation architecture to enable an ultra-flexible solar cell module from bulk mono-crystalline silicon solar wafer with 17% efficiency. This periodic corrugated array benefits from an interchangeable solar cell segmentation scheme which preserves the active silicon thickness and achieves flexibility via interdigitated back contacts. These cells

  6. Prospects of Graphene as a Potential Carrier-Transport Material in Third-Generation Solar Cells.

    Science.gov (United States)

    Chowdhury, Towhid H; Islam, Ashraful; Mahmud Hasan, A K; Terdi, M Asri Mat; Arunakumari, M; Prakash Singh, Surya; Alam, Md Khorshed; Bedja, Idriss M; Hafidz Ruslan, Mohd; Sopian, Kamaruzzaman; Amin, Nowshad; Akhtaruzzaman, Md

    2016-04-01

    Third-generation solar cells are understood to be the pathway to overcoming the issues and drawbacks of the existing solar cell technologies. Since the introduction of graphene in solar cells, it has been providing attractive properties for the next generation of solar cells. Currently, there are more theoretical predictions rather than practical recognitions in third-generation solar cells. Some of the potential of graphene has been explored in organic photovoltaics (OPVs) and dye-sensitized solar cells (DSSCs), but it has yet to be fully comprehended in the recent third-generation inorganic-organic hybrid perovskite solar cells. In this review, the diverse role of graphene in third-generation OPVs and DSSCs will be deliberated to provide an insight on the prospects and challenges of graphene in inorganic-organic hybrid perovskite solar cells. © 2016 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. High Mobility, Hole Transport Materials for Highly Efficient PEDOT:PSS Replacement in Inverted Perovskite Solar Cells

    KAUST Repository

    Neophytou, Marios

    2017-04-24

    Perovskite solar cells are one of the most promising photovoltaic technologies, due to their rapid increase in power conversion efficiency (3.8% to 21.1%) in a very short period of time and the relative ease of their fabrication compared to traditional inorganic solar cells. One of the drawbacks of perovskite solar cells is their limited stability in non-inert atmospheres. In the inverted device configuration this lack of stability can be attributed to the inclusion of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate(PEDOT:PSS) as the hole transporting layer. Herein we report the synthesis of two new triarylamine based hole transporting materials, synthesised from readily available starting materials. These new materials show increased power conversion efficiencies, of 13.0% and 12.1%, compared to PEDOT:PSS (10.9%) and exhibit increased stability achieving lifetimes in excess of 500 hours. Both molecules are solution processible at low temperatures and offer potential for low cost, scalable production on flexible substrates for large scale perovskite solar cells.

  8. Toxicity of functional nano-micro zinc oxide tetrapods: impact of cell culture conditions, cellular age and material properties.

    Science.gov (United States)

    Papavlassopoulos, Heike; Mishra, Yogendra K; Kaps, Sören; Paulowicz, Ingo; Abdelaziz, Ramzy; Elbahri, Mady; Maser, Edmund; Adelung, Rainer; Röhl, Claudia

    2014-01-01

    With increasing production and applications of nanostructured zinc oxide, e.g., for biomedical and consumer products, the question of safety is getting more and more important. Different morphologies of zinc oxide structures have been synthesized and accordingly investigated. In this study, we have particularly focused on nano-micro ZnO tetrapods (ZnO-T), because their large scale fabrication has been made possible by a newly introduced flame transport synthesis approach which will probably lead to several new applications. Moreover, ZnO-T provide a completely different morphology then classical spherical ZnO nanoparticles. To get a better understanding of parameters that affect the interactions between ZnO-T and mammalian cells, and thus their biocompatibility, we have examined the impact of cell culture conditions as well as of material properties on cytotoxicity. Our results demonstrate that the cell density of fibroblasts in culture along with their age, i.e., the number of preceding cell divisions, strongly affect the cytotoxic potency of ZnO-T. Concerning the material properties, the toxic potency of ZnO-T is found to be significantly lower than that of spherical ZnO nanoparticles. Furthermore, the morphology of the ZnO-T influenced cellular toxicity in contrast to surface charges modified by UV illumination or O2 treatment and to the material age. Finally, we have observed that direct contact between tetrapods and cells increases their toxicity compared to transwell culture models which allow only an indirect effect via released zinc ions. The results reveal several parameters that can be of importance for the assessment of ZnO-T toxicity in cell cultures and for particle development.

  9. The Modification of Fuel Cell-Based Breath Alcohol Sensor Materials to Improve Water Retention of Sensing Performance

    Science.gov (United States)

    Allan, Jesse

    Fuel cell based breath alcohol sensors (BrASs) are one of the most important tools used by law enforcement today. The ability to screen potentially intoxicated subjects with the ease, speed, and flexibility the BrAS can provide is unmatched by any other device of its kind. While these devices are used globally, they all suffer from a common deficiency: reliance on water. The ability of the fuel cell sensor to manage water content is one of the greatest fundamental challenges facing this technology today. In order to evaluate the fuel cell sensor device, a methodology was required that would allow in-house sensor testing to be coupled with a diagnostic testing method to not only test materials sensing performance, but also determine why a sensor behaved how it did. To do this, a next-generation fuel cell was designed specifically for sensor testing along with a test station that allowed for rapid response and sensor characteristics of a given material. The fuel cell was designed to allow in-situ testing of a membrane electrode assembly (MEA) of interest using cyclic voltammetry and electrochemical impedance spectroscopy. The in-house design was validated against a commercial cell to provide feedback on how materials in the in-house cell would behave in a commercial designed unit. The results showed that our cell with a commercial MEA behaved identically to a commercial cell with the same MEA. Following validation of our cell, common membrane materials were investigated to identify their suitability in a senor role. The materials chosen were designed for power generating devices, so they provided a benchmark to identify which properties would be important for sensor operation. It was found that while the Nafion membrane and sulfonated poly (ether ether ketone) did show performance increases over the commercial MEA, the thin characteristics of these membranes limited performance in drier conditions. From these results, it was determined that thicker membrane materials

  10. 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.

  11. 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.

  12. Fluorine-substituted benzothiadiazole-based hole transport materials for highly efficient planar perovskite solar cells with a FF exceeding 80.

    Science.gov (United States)

    Wu, Fei; Ji, Yu; Zhong, Cheng; Liu, Yuan; Tan, Luxi; Zhu, Linna

    2017-08-11

    Fluorine-substituted benzothiadiazole (BT) was introduced as a core structure to construct new hole transport materials. Planar perovskite solar cells with conventional materials (CH 3 NH 3 PbI 3-x Cl x ) were fabricated. The perovskite solar cells using monofluorinated BT exhibit a leading efficiency of 18.54% with a FF as high as 81%.

  13. 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.

  14. 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.

  15. Cultivation and characterization of cornea limbal epithelial stem cells on lens capsule in animal material-free medium.

    Directory of Open Access Journals (Sweden)

    Réka Albert

    Full Text Available A simple, reproducible, animal-material free method for cultivating and characterizing cornea limbal epithelial stem cells (LESCs on human lens capsule (LC was developed for future clinical transplantation. The limbal tissue explants (2 × 2 × 0.25 mm were harvested from 77 cadavers and expanded ex vivo on either cell culture plates or LC in medium containing human serum as the only growth supplement. Cell outgrowth at the edge of the explants was observed within 24 hours of cultivation and achieved viable outgrowth (>97% viability as measured by MTT assay and flow cytometry within two weeks. The outgrowing cells were examined by genome-wide microarray including markers of stemness (p63α, ABCG2, CK19, Vimentin and Integrin α9, proliferation (Ki-67, limbal epithelial cells (CK 8/18 and 14 and differentiated cornea epithelial cells (CK 3 and 12. Immunostaining revealed the non-hematopoietic, -endothelial and -mesenchymal stem cell phenotype of the LESCs and the localization of specific markers in situ. Cell adhesion molecules, integrins and lectin-based surface carbohydrate profiling showed a specific pattern on these cells, while colony-formation assay confirmed their clonal potency. The LESCs expressed a specific surface marker fingerprint (CD117/c-kit, CXCR4, CD144/VE-Cadherin, CD146/MCAM, CD166/ALCAM, and surface carbohydrates: WGA, ConA, RCA, PNA and AIL which can be used for better localization of the limbal stem cell niche. In summary, we report a novel method combining the use of a medium with human serum as the only growth supplement with LC for cultivating, characterizing and expanding cornea LESCs from cadavers or alternatively from autologous donors for possible treatment of LESC deficiency.

  16. Cultivation and characterization of cornea limbal epithelial stem cells on lens capsule in animal material-free medium.

    Science.gov (United States)

    Albert, Réka; Veréb, Zoltán; Csomós, Krisztián; Moe, Morten C; Johnsen, Erik O; Olstad, Ole Kristoffer; Nicolaissen, Bjørn; Rajnavölgyi, Eva; Fésüs, László; Berta, András; Petrovski, Goran

    2012-01-01

    A simple, reproducible, animal-material free method for cultivating and characterizing cornea limbal epithelial stem cells (LESCs) on human lens capsule (LC) was developed for future clinical transplantation. The limbal tissue explants (2 × 2 × 0.25 mm) were harvested from 77 cadavers and expanded ex vivo on either cell culture plates or LC in medium containing human serum as the only growth supplement. Cell outgrowth at the edge of the explants was observed within 24 hours of cultivation and achieved viable outgrowth (>97% viability as measured by MTT assay and flow cytometry) within two weeks. The outgrowing cells were examined by genome-wide microarray including markers of stemness (p63α, ABCG2, CK19, Vimentin and Integrin α9), proliferation (Ki-67), limbal epithelial cells (CK 8/18 and 14) and differentiated cornea epithelial cells (CK 3 and 12). Immunostaining revealed the non-hematopoietic, -endothelial and -mesenchymal stem cell phenotype of the LESCs and the localization of specific markers in situ. Cell adhesion molecules, integrins and lectin-based surface carbohydrate profiling showed a specific pattern on these cells, while colony-formation assay confirmed their clonal potency. The LESCs expressed a specific surface marker fingerprint (CD117/c-kit, CXCR4, CD144/VE-Cadherin, CD146/MCAM, CD166/ALCAM, and surface carbohydrates: WGA, ConA, RCA, PNA and AIL) which can be used for better localization of the limbal stem cell niche. In summary, we report a novel method combining the use of a medium with human serum as the only growth supplement with LC for cultivating, characterizing and expanding cornea LESCs from cadavers or alternatively from autologous donors for possible treatment of LESC deficiency.

  17. 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.

  18. 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.

  19. Development of Synthetic and Natural Materials for Tissue Engineering Applications Using Adipose Stem Cells

    OpenAIRE

    Yunfan He; Feng Lu

    2016-01-01

    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 recon...

  20. 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.

  1. 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.

  2. The Biomineralization of a Bioactive Glass-Incorporated Light-Curable Pulp Capping Material Using Human Dental Pulp Stem Cells

    OpenAIRE

    Jun, Soo-Kyung; Lee, Jung-Hwan; Lee, Hae-Hyoung

    2017-01-01

    The aim of this study was to investigate the biomineralization of a newly introduced bioactive glass-incorporated light-curable pulp capping material using human dental pulp stem cells (hDPSCs). The product (Bioactive? [BA]) was compared with a conventional calcium hydroxide-incorporated (Dycal [DC]) and a light-curable (Theracal? [TC]) counterpart. Eluates from set specimens were used for investigating the cytotoxicity and biomineralization ability, determined by alkaline phosphatase (ALP) a...

  3. Evaluation of the anti-inflammatory actions of various functional food materials including glucosamine on synovial cells.

    Science.gov (United States)

    Yamagishi, Yoshie; Someya, Akimasa; Imai, Kensuke; Nagao, Junji; Nagaoka, Isao

    2017-08-01

    The anti-inflammatory actions of glucosamine (GlcN) on arthritic disorders involve the suppression of inflammatory mediator production from synovial cells. GlcN has also been reported to inhibit the activation of the p38 mitogen-activated protein kinase (MAPK) pathway. The present study aimed to determine the cooperative and anti‑inflammatory actions of functional food materials and evaluated the production of interleukin (IL)‑8 and phosphorylation of p38 MAPK in IL-1β-activated synovial cells, incubated with the combination of GlcN and various functional food materials containing L‑methionine (Met), undenatured type II collagen (UC‑II), chondroitin sulfate (CS), methylsulfonylmethane (MSM) and agaro-oligosaccharide (AO). The results indicated that Met, UC‑II, CS, MSM and AO slightly or moderately suppressed the IL-1β-stimulated IL‑8 production by human synovial MH7A cells. The same compounds further decreased the IL‑8 level lowered by GlcN. Similarly, they slightly suppressed the phosphorylation level of p38 MAPK and further reduced the phosphorylation level lowered by GlcN. These observations suggest a possibility that these functional food materials exert an anti‑inflammatory action (inhibition of IL‑8 production) in combination with GlcN by cooperatively suppressing the p38 MAPK signaling (phosphorylation).

  4. Generalized inclusion of short-range ordering effects in the coherent potential approximation for complex-unit-cell materials

    Science.gov (United States)

    Marmodoro, Alberto; Ernst, Arthur; Ostanin, Sergei; Staunton, Julie B.

    2013-03-01

    The coherent potential approximation has historically allowed the efficient study of disorder effects over a variety of solid state systems. Its original formulation is, however, limited to a single-site or uncorrelated model of local substitutions. This neglects the effects of correlation and short-range ordering, often found in real materials. Recent theoretical work has shown one possible way to systematically address such shortcomings for simple materials with only one element per unit cell. We briefly review the basic ideas of such development within the framework of multiple scattering theory and suggest its generalization to materials with complex lattices. We validate our extension through a systematic comparison with a classic Cu1-cZnc reference test case and propose, for further illustration of local environment effects, the example of the yttria-stabilized cubic phase of zirconia, re-examined through various techniques for the first-principles treatment of disorder.

  5. 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.

  6. Cell-to-module optical loss/gain analysis for various photovoltaic module materials through systematic characterization

    Science.gov (United States)

    Hsian Saw, Min; Khoo, Yong Sheng; Singh, Jai Prakash; Wang, Yan

    2017-08-01

    Reducing levelized cost of electricity (LCOE) is important for solar photovoltaics to compete against other energy sources. Thus, the focus should not only be on improving the solar cell efficiency, but also on continuously reducing the losses (or achieving gain) in the cell-to-module process. This can be achieved by choosing the appropriate module material and design. This paper presents a detailed and systematic characterization of various photovoltaic (PV) module materials (encapsulants, tabbing ribbons, and backsheets) and an evaluation of their impact on the output power of silicon wafer-based PV modules. Various characterization tools/techniques, such as UV-vis (reflectance) measurement, external quantum efficiency (EQE) measurement and EQE line-scan are used. Based on the characterization results, we use module materials with the best-evaluated optical performance to build “optimized modules”. Compared to the standard mini-module, an optical gain of more than 5% is achievable for the “optimized module” with selected module materials.

  7. STUDI PREPARASI DAN KARAKTERISASI SEL SURYA BERBASIS TITANIA MELALUI PENYISIPAN LOGAM TEMBAGA (CU DENGAN BERBAGAI VARIASI MASSA PADA LAPISAN AKTIF TITANIA

    Directory of Open Access Journals (Sweden)

    Rita Prasetyowati

    2017-05-01

                This study aims to determine the effect of insertion of copper (Cu with a variety of mass to structure morphology and composition of surface layer of titania, absorbance of titania, resistance of titania and solar cell performance based on titania.. Solar cell performance is characterized from voltage of solar cell.                 Preparation of titania-copper layer (TiO2-Cu to form a paste was made using a sol-gel method. Pasta titania-copper deposited on a transparent electrode (Indium Tin Oxide with a doctor blade method. There were five variations of Cu mass pasted on layers of titania, namely 0,050 grams (Sample 1; 0,075 grams (sample 2; 0,100 grams (3 samples; 0.0125 (sample 4 and 0.0150 (sample 5. Each variation of the mass of Cu is inserted in one gram of TiO2. SEM and EDS characterization performed on layers of titania-copper to know the structure morphology and composition of the titania-copper. Layer absorbance was characterized using UV-Visible spectrometer. Resistance of titania was measured using a Wheatstone bridge. The performance of solar cells measured by measuring the voltage of the solar cell.                  Keywords: titania, copper, surface morphology, absorbance, resistance, solar cells

  8. A Study of Solid Oxide Fuel Cell Materials at High Temperature Using an Environmental Scanning Electron Microscope

    Science.gov (United States)

    Jony, Mahfuzur Rahman

    Solid oxide fuel cells (SOFCs) are promising energy conversion devices, but their economic viability depends on long term stability of the SOFC materials at the high operating temperatures. The in-situ study of materials degradation faces a great challenge because of the unavailability of analytical methods at those high temperatures. The traditional analytical techniques for degradation measurements are widely based on post-mortem studies. The cells or cell materials are cooled down to room temperature and are then subjected to microscopy-based methods. Combining post-mortem analyses with cell modelling, several studies have reported the following microstructural degradations: (a) Lanthanum Strontium Manganite (LSM) particles, one of the most widely used cathode material, 'melt' or 'spread' at temperatures as low 850 °C without the presence of a current flow on Yttrium Stabilized Zirconia (YSZ) surface, (b) the Ni particle shapes change during oxidation of nickel to NiO and as a result of reduction of NiO to Ni during redox cycling, (c) the formation of nickel phosphide particles on the Ni/YSZ anode surface due to the presence of PH3 in coal syngas. However, these reports are limited due to the fact that analyses were done at room temperature rather at their high operating temperature. In this current study, cell materials were examined in-situ at high temperature using an Environmental Scanning Electron Microscope installed with a heating stage. High temperature images were collected for different cell materials such as silver paste, LSM particles, nickel oxide particles and secondary nickel phosphide phase formed on YSZ substrate. The images were analyzed by using ImageJ, an open source image processing software. An image analysis protocol was developed to analyze the cell materials images taken from 500 °C to 1080 °C. The image analysis provides both qualitative and quantitative insight of electrode/electrolyte interface. This novel approach of the SOFC

  9. Materials and Light Management for High-Efficiency Thin-Film Silicon Solar Cells

    NARCIS (Netherlands)

    Tan, H.

    2015-01-01

    Direct conversion of sunlight into electricity is one of the most promising approaches to provide sufficient renewable energy for humankind. Solar cells are such devices which can efficiently generate electricity from sunlight through the photovoltaic effect. Thin-film silicon solar cells, a type of

  10. In vitro mesenchymal stem cell response to a CO{sub 2} laser modified polymeric material

    Energy Technology Data Exchange (ETDEWEB)

    Waugh, D.G., E-mail: d.waugh@chester.ac.uk [Laser Engineering and Manufacturing Research Centre, Faculty of Science and Engineering, University of Chester, Chester CH1 4BJ (United Kingdom); Hussain, I. [School of Life Sciences, Brayford Pool, University of Lincoln, Lincoln LN6 7TS (United Kingdom); Lawrence, J.; Smith, G.C. [Laser Engineering and Manufacturing Research Centre, Faculty of Science and Engineering, University of Chester, Chester CH1 4BJ (United Kingdom); Cosgrove, D. [School of Life Sciences, Brayford Pool, University of Lincoln, Lincoln LN6 7TS (United Kingdom); Toccaceli, C. [Laser Engineering and Manufacturing Research Centre, Faculty of Science and Engineering, University of Chester, Chester CH1 4BJ (United Kingdom)

    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 CO{sub 2} laser surface treated nylon 6,6 highlighting its potential as an inexpensive platform to manipulate stem cell growth on a pharmaceutical scale. Through CO{sub 2} 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 4.3 μm, the contact angle was modulated by up to 5° and the surface oxygen content increased by up to 1 atom %. Following mesenchymal stem cell growth on the laser treated samples, it was identified that CO{sub 2} laser surface treatment gave rise to an enhanced response with an increase in viable cell count of up to 60,000 cells/ml when compared to the as-received sample. The effect of surface parameters modified by the CO{sub 2} 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.

  11. 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

    Background: Regeneration of periodontal tissues is a major goal of periodontal therapy. Dental pulp stem cells (DPSCs) show mesenchymal cell properties with the potential for dental tissue engineering. Enamel matrix derivative (EMD) and platelet-derived growth factor (PDGF) are examples...

  12. 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

  13. 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.

  14. Advanced Solid Oxide Cell Architecture and Materials for Durable, Regenerative Operation at Pressure, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — PCI will develop and demonstrate advanced materials and innovative structural elements integrated within the stack for efficient H2O/CO2 electrolysis to overcome...

  15. Nanomaterial-induced cell death in pulmonary and hepatic cells following exposure to three different metallic materials

    DEFF Research Database (Denmark)

    Kermanizadeh, Ali; Jantzen, Kim; Ward, Michael B

    2017-01-01

    Autophagy is the catabolic process involving the sequestration of the cytoplasm within double-membrane vesicles, which fuse with lysosomes to form autolysosomes in which autophagic targets are degraded. Since most endocytic routes of nanomaterial uptake converge upon the lysosome and the possibil...... cytoskeleton. This response was not observed following the exposure to low-toxicity TiO2 NMs. Overall, the results show that high toxicity NMs can cause a dysfunction in the autophagy pathway which is associated with apoptotic cell death....... and the possibility that autophagy induction by NMs may be an attempt by the cell to self-preserve following the external challenge, this study investigated the role of autophagy following exposure to a panel of widely used metal-based NMs with high toxicity (Ag and ZnO) or low toxicity (TiO2) in a pulmonary (A549......) and hepatic (HepG2) cell line. The in vitro exposure to the Ag and ZnO NMs resulted in the induction of both apoptosis and autophagy pathways in both cell types. However, the progression of autophagy was blocked in the formation of the autolysosome, which coincided with morphologic changes in the actin...

  16. In vitro evaluation of different dental materials used for the treatment of extensive cervical root defects using human periodontal cells.

    Science.gov (United States)

    Michel, Annemarie; Erber, Ralf; Frese, Cornelia; Gehrig, Holger; Saure, Daniel; Mente, Johannes

    2017-04-01

    Repair materials for extensive cervical root defects may come in direct contact with periodontal tissues. This in vitro study compared the effects of four calcium silicate cements (CSC), one resin-modified glass ionomer cement, and one glass carbomer cement on primary human gingival fibroblasts (HGF), alveolar osteoblasts (HAO), and a human osteoblast cell line (hFOB 1.19). HGF, HAO, and hFOB were seeded on discoid test specimens. Relative numbers of viable cells were quantitatively assessed after 1 and 24 h for cytotoxicity/adhesion assays and after 4, 24, 48, and 72 h for proliferation assays. Data were statistically analyzed using non-parametric tests (α = 0.05). Relative to the control (100 %), CSC allowed for mean numbers of 71-81 % viable HGF and 80-82 % viable HAO. Then, 64 % of HGF and 56 % of HAO were assessed on GC Fuji II LC. Mean numbers of viable cells were 59-64 % HGF and 67-68 % HAO for GCP Glass Fill specimens. Cells exposed to CSC over 24 h remained viable and even increased in number. Both cell types adhered almost equally well to CSC and GC Fuji II LC. GCP Glass Fill continued to decrease cell viability and adhesion. CSC-based materials and GC Fuji II LC allowed for HGF and hFOB proliferation; however, none of the tested materials specifically stimulated cell proliferation. CSC characterized by low cytotoxicity. GC Fuji II LC shows moderate cytotoxic effects. ProRoot MTA, Harvard MTA, Biodentine, EndoSequence putty, and GC Fuji II LC allow HGF and HAO to adhere and HGF and hFOB to proliferate. GCP Glass Fill decreases cell viability, adhesion, and proliferation. CSC remain the paramount biologic choice for the repair of extensive cervical root defects. GC Fuji II LC might be considered in addition to CSC when the defect comprises supracrestal areas and the restoration requires superior aesthetic and mechanical characteristics.

  17. 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.

  18. Electrochemical characterization of nano-sized Pd-based catalysts as cathode materials in direct methanol fuel cells.

    Science.gov (United States)

    Choi, M; Han, C; Kim, I T; An, J C; Lee, J J; Lee, H K; Shim, J

    2011-01-01

    To improve the catalytic activity of palladium (Pd) as a cathode catalyst in direct methanol fuel cells (DMFCs), we prepared palladium-titanium oxide (Pd-TiO2) catalysts which the Pd and TiO2 nanoparticles were simultaneously impregnated on carbon. We selected Pd and TiO2 as catalytic materials because of their electrochemical stability in acid solution. The crystal structure and the loading amount of Pd and TiO2 on carbon were characterized by X-ray diffraction (XRD) and energy dispersive X-ray microanalysis (EDX). The electrochemical characterization of Pd-TiO2/C catalysts for the oxygen reduction reaction was carried out in half and single cell systems. The catalytic activities of the Pd-TiO2 catalysts were strongly influenced by the TiO2 content. In the single cell test, the Pd-TiO2 catalysts showed very comparable performance to the Pt catalyst.

  19. 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)

  20. Development and optimization of radiographic and tomographic methods for characterization of water transport processes in PEM fuel cell materials

    International Nuclear Information System (INIS)

    Markoetter, Henning

    2013-01-01

    Water transport in polymer electrolyte membrane fuel cells (PEMFC) was non-destructively studied during operation with synchrotron X-ray radiography and tomography. The focus was set on the influence of the three-dimensional morphology of the cell materials on the water distribution and transport. Water management is still one of the mayor issues in PEMFC research. If the fuel cell is too dry, the proton conductivity (of the membrane) decreases leading to a performance loss and, in the worst case, to an irreversible damage of the membrane. On the other hand, the presence of water hinders the gas supply and causes a decrease in the cell performance. For this reason, effective water transport is a prerequisite for successful fuel cell operation. In this work the three-dimensional water transport through the gas diffusion layer (GDL) and its correlated with the 3D morphology of the cell materials has been revealed for the first time. It was shown that water is transported preferably through only a few larger pores which form transport paths of low resistance. This effect is pronounced because of the hydrophobic properties of the employed materials. In addition, water transport was found to be bidirectional, i. e. at appropriate locations a back and forth transport between GDL and flow field channels was observed. Furthermore, liquid water in the GDL was found to agglomerate preferably at the ribs of the flow field. This can be explained by condensation due to a temperature gradient in the cell and by the position, which is sheltered from the gas flow. Larger water accumulations in the gas supply channels were mainly attached to the channel wall opposing the GDL. The gas flow can bypass these agglomerations allowing a continuous gas supply. Moreover, it was shown that randomly distributed cracks in the micro porous layers (MPL) play an important role for the agglomeration of liquid water as they form preferred low resistance transport paths. In this work also

  1. Naphthalene Diimide Based n-Type Conjugated Polymers as Efficient Cathode Interfacial Materials for Polymer and Perovskite Solar Cells.

    Science.gov (United States)

    Jia, Tao; Sun, Chen; Xu, Rongguo; Chen, Zhiming; Yin, Qingwu; Jin, Yaocheng; Yip, Hin-Lap; Huang, Fei; Cao, Yong

    2017-10-18

    A series of naphthalene diimide (NDI) based n-type conjugated polymers with amino-functionalized side groups and backbones were synthesized and used as cathode interlayers (CILs) in polymer and perovskite solar cells. Because of controllable amine side groups, all the resulting polymers exhibited distinct electronic properties such as oxidation potential of side chains, charge carrier mobilities, self-doping behaviors, and interfacial dipoles. The influences of the chemical variation of amine groups on the cathode interfacial effects were further investigated in both polymer and perovskite solar cells. We found that the decreased electron-donating property and enhanced steric hindrance of amine side groups substantially weaken the capacities of altering the work function of the cathode and trap passivation of the perovskite film, which induced ineffective interfacial modifications and declining device performance. Moreover, with further improvement of the backbone design through the incorporation of a rigid acetylene spacer, the resulting polymers substantially exhibited an enhanced electron-transporting property. Upon use as CILs, high power conversion efficiencies (PCEs) of 10.1% and 15.2% were, respectively, achieved in polymer and perovskite solar cells. Importantly, these newly developed n-type polymers were allowed to be processed over a broad thickness range of CILs in photovoltaic devices, and a prominent PCE of over 8% for polymer solar cells and 13.5% for perovskite solar cells can be achieved with the thick interlayers over 100 nm, which is beneficial for roll-to-roll coating processes. Our findings contribute toward a better understanding of the structure-performance relationship between CIL material design and solar cell performance, and provide important insights and guidelines for the design of high-performance n-type CIL materials for organic and perovskite optoelectronic devices.

  2. A large format in operando wound cell for analysing the structural dynamics of lithium insertion materials

    Science.gov (United States)

    Brant, William R.; Roberts, Matthew; Gustafsson, Torbjörn; Biendicho, Jordi Jacas; Hull, Stephen; Ehrenberg, Helmut; Edström, Kristina; Schmid, Siegbert

    2016-12-01

    This paper presents a large wound cell for in operando neutron diffraction (ND) from which high quality diffraction patterns are collected every 15 min while maintaining conventional electrochemical performance. Under in operando data collection conditions the oxygen atomic displacement parameters (ADPs) and cell parameters were extracted for Li0.18Sr0.66Ti0.5Nb0.5O3. Analysis of diffraction data collected under in situ conditions revealed that the lithium is located on the (0.5 0.5 0) site, corresponding to the 3c Wyckoff position in the cubic perovskite unit cell, after the cell is discharged to 1 V. When the cell is discharged under potentiostatic conditions the quantity of lithium on this site increases, indicating a potential position where lithium becomes pinned in the thermodynamically stable phase. During this potentiostatic step the oxygen ADPs reduce significantly. On discharge, however, the oxygen ADPs were observed to increase gradually as more lithium is inserted into the structure. Finally, the rate of unit cell expansion changed by ∼44% once the lithium content approached ∼0.17 Li per formula unit. A link between lithium content and degree of mobility, disorder of the oxygen positions and changing rate of unit cell expansion at various stages during lithium insertion and extraction is thus presented.

  3. Novel Materials that Enhance Efficiency and Radiation Resistance of Solar Cells, Phase II

    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...

  4. Development of Synthetic and Natural Materials for Tissue Engineering Applications Using Adipose Stem Cells.

    Science.gov (United States)

    He, Yunfan; Lu, Feng

    2016-01-01

    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.

  5. Measurement of wood/plant cell or composite material attributes with computer assisted tomography

    Science.gov (United States)

    West, Darrell C.; Paulus, Michael J.; Tuskan, Gerald A.; Wimmer, Rupert

    2004-06-08

    A method for obtaining wood-cell attributes from cellulose containing samples includes the steps of radiating a cellulose containing sample with a beam of radiation. Radiation attenuation information is collected from radiation which passes through the sample. The source is rotated relative to the sample and the radiation and collecting steps repeated. A projected image of the sample is formed from the collected radiation attenuation information, the projected image including resolvable features of the cellulose containing sample. Cell wall thickness, cell diameter (length) and cell vacoule diameter can be determined. A system for obtaining physical measures from cellulose containing samples includes a radiation source, a radiation detector, and structure for rotating the source relative to said sample. The system forms an image of the sample from the radiation attenuation information, the image including resolvable features of the sample.

  6. Low Cost, Epitaxial Growth of II-VI Materials for Multijunction Photovoltaic Cells

    Energy Technology Data Exchange (ETDEWEB)

    Hardin, Brian E. [PLANT PV, Inc., Oakland, CA (United States); Peters, Craig H. [PLANT PV, Inc., Oakland, CA (United States)

    2014-04-30

    Multijunction solar cells have theoretical power conversion efficiencies in excess of 29% under one sun illumination and could become a highly disruptive technology if fabricated using low cost processing techniques to epitaxially grow defect tolerant, thin films on silicon. The PLANT PV/Molecular Foundry team studied the feasibility of using cadmium selenide (CdSe) as the wide band-gap, top cell and Si as the bottom cell in monolithically integrated tandem architecture. The greatest challenge in developing tandem solar cells is depositing wide band gap semiconductors that are both highly doped and have minority carrier lifetimes greater than 1 ns. The proposed research was to determine whether it is possible to rapidly grow CdSe films with sufficient minority carrier lifetimes and doping levels required to produce an open-circuit voltage (Voc) greater than 1.1V using close-space sublimation (CSS).

  7. Novel Materials that Enhance Efficiency and Radiation Resistance of Solar Cells, Phase I

    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 while...

  8. 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.

  9. From Nano to Macro: Multiscale Materials for Improved Stem Cell Culturing and Analysis

    NARCIS (Netherlands)

    Leijten, Jeroen Christianus Hermanus; Khademhosseini, A.

    2016-01-01

    Stem cells respond to nanoscale, microscale, and macroscale cues, such as matrix, growth factors, and niche organization, which are difficult to physiologically recapitulate in culture. We discuss how utilizing bioengineering approaches to manipulate and integrate spatiotemporal cues across these

  10. 49 CFR 173.230 - Fuel cell cartridges containing hazardous material.

    Science.gov (United States)

    2010-10-01

    ... integral vent feature) is deemed to pass the fire test if: (A) The internal pressure vents to zero gauge... required to power the equipment, plus two spares; (5) Large robust articles containing fuel cells may be...

  11. Materiais cerâmicos para células a combustível Ceramic materials for fuel cells

    Directory of Open Access Journals (Sweden)

    D. Z. de Florio

    2004-12-01

    Full Text Available A partir da definição de células a combustível, é feita uma introdução sucinta dos tipos de células e dos materiais cerâmicos que são empregados em projeto e fabricação destes dispositivos geradores de energia elétrica. Tomando por base a ampla literatura científica disponível em publicações periódicas internacionais indexadas e arbitradas, bem como patentes, são relatados com detalhes os materiais cerâmicos com comportamento elétrico adequado para uso como eletrólitos, anodos, catodos, interconectores e selantes, que são os componentes básicos de células a combustível de óxidos sólidos. Por fim, é feita uma avaliação do estado da arte na pesquisa e desenvolvimento de materiais cerâmicos para uso em células a combustível de óxidos sólidos.Basic definitions of fuel cells and a brief introduction of different types of fuel cells are given. A review of the most important ceramic materials being considered for the design and fabrication of devices for producing electrical energy is presented. Ceramic materials with suitable electrical behavior to be used as electrolytes, anodes, cathodes, interconnectors, and sealants of solid oxide fuel cells are reported with details, taking into account the large number of available indexed and refereed scientific publications and patents. Finally, an evaluation of the state of the art of the research and development of ceramic materials for solid oxide fuel cells is presented.

  12. A novel bio-functional material based on mammalian cell aggresomes

    OpenAIRE

    Rodríguez-Carmona, Escarlata

    2015-01-01

    Aggresomes are protein aggregates found in mammalian cells when the intracellular protein degradation machinery is over-titered. Despite that they abound in cells producing recombinant proteins of biomedical and biotechnological interest, the physiological roles of these protein clusters and the functional status of the embedded proteins remain basically unexplored. In this work, we have determined for the first time that, like in bacterial inclusion bodies, deposition of recombinant proteins...

  13. 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

  14. Fill factor enhancement of organic solar cells based on a wide bandgap phosphorescent material and C{sub 60}

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Junsheng, E-mail: jsyu@uestc.edu.cn; Zang, Yue; Li, Haiqiang; Huang, Jiang

    2012-08-31

    Planar heterojunction organic solar cells using wide bandgap phosphorescent material bis[2-(4-tertbutylphenyl)benzothiazolato-N,C{sup 2'}] iridium (acetylacetonate) [(t-bt){sub 2}Ir(acac)] as electron donor and fullerene (C{sub 60}) as electron acceptor were fabricated. A large open circuit voltage of 0.94 V was achieved due to low highest occupied molecular orbital level of (t-bt){sub 2}Ir(acac). The effect of different hole transport layers and substrate heating were investigated to improve fill factor. It is shown that the open circuit voltage is strongly influenced by the interface energy barrier, whereas the fill factor is mainly limited by the charge carrier transport properties in active materials. The fill factor was significantly improved by either using hole transport layer with high carrier mobility or increasing the hole mobility of (t-bt){sub 2}Ir(acac). A power conversion efficiency of 2.10% under AM 1.5 solar illumination at an intensity of 100 mW/cm{sup 2} was achieved by heating the substrate during the deposition of active materials. - Highlights: Black-Right-Pointing-Pointer Organic solar cells based on wide bandgap phosphorescent material were fabricated. Black-Right-Pointing-Pointer A relatively high open circuit voltage about 0.94 V was achieved. Black-Right-Pointing-Pointer The fill factor (FF) is mainly limited by the charge transport properties. Black-Right-Pointing-Pointer The FF can be improved by using hole transport layers with high mobility. Black-Right-Pointing-Pointer Increasing the mobility of active materials can also enhance the FF.

  15. Influence of CAD/CAM all-ceramic materials on cell viability, migration ability and adenylate kinase release of human gingival fibroblasts and oral keratinocytes.

    Science.gov (United States)

    Pabst, A M; Walter, C; Grassmann, L; Weyhrauch, M; Brüllmann, D D; Ziebart, T; Scheller, H; Lehmann, K M

    2014-05-01

    The aim of this study was to analyze the influence of four CAD/CAM all-ceramic materials on cell viability, migration ability and adenylate kinase (ADK) release of human gingival fibroblasts (HGF) and oral keratinocytes (HOK). HGF and HOK were cultured on disc-shaped CAD/CAM all-ceramic materials (e.max CAD LT, e.max CAD HT, Empress CAD and Mark II) and on discs made of tissue culture polystyrene surface (TCPS) serving as control. Cell viability was analyzed by using an MTT assay, and migration ability was investigated by a scratch assay. A ToxiLight assay has been performed to analyze the effect of all-ceramic materials on ADK release and cell apoptosis. At MTT assay for HGF, no significant decrease of cell viability could be detected at all points of measurement (p each > 0.05), while HOK demonstrated a significant decrease in cell viability especially on Empress CAD and Mark II at each point of measurement (p each materials at all points of measurement (between -36 % and -71 %; p each ceramic materials could be investigated. This study disclosed significant differences in cell viability and migration ability of HGF and HOK on CAD/CAM all-ceramic materials. CAD/CAM all-ceramic materials can influence oral cell lines responsible for soft tissue creation which may affect the esthetic outcome.

  16. Material Exchange in Photoreceptor Transplantation: Updating Our Understanding of Donor/Host Communication and the Future of Cell Engraftment Science

    Directory of Open Access Journals (Sweden)

    Philip E. B. Nickerson

    2018-03-01

    Full Text Available Considerable research effort has been invested into the transplantation of mammalian photoreceptors into healthy and degenerating mouse eyes. Several platforms of rod and cone fluorescent reporting have been central to refining the isolation, purification and transplantation of photoreceptors. The tracking of engrafted cells, including identifying the position, morphology and degree of donor cell integration post-transplant is highly dependent on the use of fluorescent protein reporters. Improvements in imaging and analysis of transplant recipients have revealed that donor cell fluorescent reporters can transfer into host tissue though a process termed material exchange (ME. This recent discovery has chaperoned a new era of interpretation when reviewing the field’s use of dissociated donor cell preparations, and has prompted scientists to re-examine how we use and interpret the information derived from fluorescence-based tracking tools. In this review, we describe the status of our understanding of ME in photoreceptor transplantation. In addition, we discuss the impact of this discovery on several aspects of historical rod and cone transplantation data, and provide insight into future standards and approaches to advance the field of cell engraftment.

  17. The influence of hybrid alumina/titania materials as electron transmission layer in planar high-performance perovskite solar cells

    Science.gov (United States)

    Yuan, Songyang; Xia, Chao; Zhang, Chongzhen; Song, Weidong; Qi, Mingyue; Wang, Rupeng; Zhao, Liangliang; Li, Shuti

    2017-11-01

    As one of main layers in hybrid organic-inorganic perovskite solar cells (PSCs), electron transport materials (ETM) play an important role in getting high photoelectric conversion efficiency (PCE). Here, we investigate Al2O3/TiO2 hybrid materials as electron transmission layer in planar perovskite solar cells. The hybrid Al2O3/TiO2 material is proved to induce a better crystal quality of CH3NH3PbCl3- x I x perovskite layer as confirmed by X-ray diffractometer (XRD). The new-formed compact rough surface of ETM is responsible for the better excited electron transmission and light absorption, thus resulting in the improvement of short-circuit current ( J sc). Meanwhile, the embedded Al2O3 plays a key role in shifting the conduction band edge of ETM, thereby leading to the improvement of photo-voltage. The optimal value is obtained with the test of sequential changing Al2O3/TiO2 concentration ratio. Compared to the device with pure TiO2 as ETM, the devices assembled with Al2O3/TiO2 hybrid ETM showed improvement in J sc (from 13.65 to 18.71 mA/cm2) as well as in V oc (from 0.95 to 1.00 V), which brings about 27.6% enhancement in PCE based on the multifunctional hybrid TiO2/ Al2O3 ETM.

  18. Evaluation of Ni/SDC as anode material for dry CH4 fueled Solid Oxide Fuel Cells

    Science.gov (United States)

    Wang, Zhiming; Li, Yongdan; Schwank, Johannes W.

    2014-02-01

    A Ni/Sm0.2Ce0.8O1.9 (SDC) composite was employed as anode material for direct electrochemical oxidation (DEO) of dry CH4 in a solid oxide fuel cell. The anodic performance was investigated at temperatures between 600 °C and 700 °C using SDC as electrolyte material and Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) as cathode material. The single cell exhibited maximum power densities of 671 mW cm-2, 494 mW cm-2 and 305 mW cm-2 in dry CH4 at 700 °C, 650 °C and 600 °C, respectively. Remarkably, at 700 °C the power density in CH4 was higher than in H2, thanks to the carbon tolerance of the anode. Durability tests under constant 300 mA output current showed only 3.7% performance loss after 72 h operation. The results demonstrate that Ni/SDC can be used as anode for the DEO of dry CH4 even at temperatures as low as 600 °C.

  19. Thermal management analysis of a Li-ion battery cell using phase change material loaded with carbon fibers

    International Nuclear Information System (INIS)

    Samimi, Fereshteh; Babapoor, Aziz; Azizi, Mohammadmehdi; Karimi, Gholamreza

    2016-01-01

    High latent heat of PCMs (phase change materials) has made them as one of the most important materials for thermal management purposes. However, PCMs’ low thermal diffusivities could limit their use in applications which require fast thermal response. The goal of this study is to simulate thermal performance of a lithium ion battery cell in the presence of carbon fiber-PCM composites. The effect of carbon fiber loading within the PCM on thermal performance is studied and the results are compared with the experimental data. The results showed that the presence of carbon fibers increases the effective thermal conductivity of PCM and hence influences temperature distribution within the cell. PCM composites containing higher percentages of carbon fibers present a more uniform temperature distribution. The results showed that the minimum and maximum thermal conductivity enhancement of 85% and 155% respectively (105% on average). A reasonable agreement is obtained between the simulation results and the experimental data. - Highlights: • Phase change materials (PCMs) are used for thermal management purposes. • Effective thermal conductivity of PCMs can be enhanced by loading carbon fibers. • Thermal performance of a battery is studied in presence of carbon fiber loaded PCM. • The presence of carbon fibers in the PCM can improve Li-ion battery performance.

  20. 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.

  1. Development of materials for use in solid oxid fuel cells anodes using renewable fuels in direct operation

    International Nuclear Information System (INIS)

    Lima, D.B.P.L. de; Florio, D.Z. de; Bezerra, M.E.O.

    2016-01-01

    Fuel cells produce electrical current from the electrochemical combustion of a gas or liquid (H2, CH4, C2H5OH, CH3OH, etc.) inserted into the anode cell. An important class of fuel cells is the SOFC (Solid Oxide Cell Fuel). It has a ceramic electrolyte that transports protons (H +) or O-2 ions and operating at high temperatures (500-1000 °C) and mixed conductive electrodes (ionic and electronic) ceramics or cermets. This work aims to develop anodes for fuel cells of solid oxide (SOFC) in order to direct operations with renewable fuels and strategic for the country (such as bioethanol and biogas). In this context, it becomes important to study in relation to the ceramic materials, especially those that must be used in high temperatures. Some types of double perovskites such as Sr2MgMoO6 (or simply SMMO) have been used as anodes in SOFC. In this study were synthesized by the polymeric precursor method, analyzed and characterized different ceramic samples of families SMMO, doped with Nb, this is: Sr2 (MgMo)1-xNbxO6 with 0 ≤ x ≤ 0.2. The materials produced were characterized by various techniques such as, thermal analysis, X-ray diffraction and scanning electron microscopy, and electrical properties determined by dc and ac measurements in a wide range of temperature, frequency and partial pressure of oxygen. The results of this work will contribute to a better understanding of advanced ceramic properties with mixed driving (electronic and ionic) and contribute to the advancement of SOFC technology operating directly with renewable fuels. (author)

  2. Cytotoxic Evaluation of Elastomeric Dental Impression Materials on a Permanent Mouse Cell Line and on a Primary Human Gingival Fibroblast Culture

    Directory of Open Access Journals (Sweden)

    Roberta Tiozzo

    2009-08-01

    Full Text Available The need for clinically relevant in vitro tests of dental materials is widely recognized. Nearly all dental impression materials are introduced into the mouth just after mixing and allowed to set in contact with the oral tissues. Under these conditions, the materials may be toxic to cells or may sensitize the tissues. The aim of the present study is to evaluate the potential cytotoxicity of new preparations of elastomeric dental impression materials: A four vinylpolysiloxanes: Elite H-D Putty and Elite H-D Light Body (Zhermack, Badia Polesine, Rovigo, Italy; Express Putty and Express Light Body (3M ESPE AG Seefeld, Germany and B two polyethers: Impregum Penta and Permadyne Penta L (3M ESPE AG Seefeld, Germany. The cytotoxicity of these impression materials were examined using two different cell lines: Balb/c 3T3 (permanent cell line and human gingival fibroblasts (primary cell line and their effects were studied by indirect and direct tests. The direct tests are performed by placing one sample of the impression materials in the centre of the Petri dishes at the time of the seeding of cells. The cell growth was evaluated at the 12th and 24th hours by cell number. The indirect tests were performed by incubating a square of 1 cm diameter impression material in 5 mL of medium at 37 °C for 24 hours (“eluates”. Subconfluent cultures are incubated with “eluates” for 24 hours. The MTT-formazan production is the method used for measuring the cell viability. The results indicate that: a polyether materials are cytotoxic under both experimental conditions; b among vinylpolysiloxanes, only Express Light Body (3M ESPE AG Seefeld, Germany induces clear inhibition of cellular viability of Balb/c 3T3 evaluated by direct and indirect tests and c the primary cell line is less sensitive to the toxic effect than the permanent cell line.

  3. Does the tissue engineering architecture of poly(3-hydroxybutyrate) scaffold affects cell-material interactions?

    Science.gov (United States)

    Masaeli, Elahe; Morshed, Mohammad; Rasekhian, Parsa; Karbasi, Saeed; Karbalaie, Khadije; Karamali, Fereshte; Abedi, Daryoush; Razavi, Shahnaz; Jafarian-Dehkordi, Abbas; Nasr-Esfahani, Mohammad Hossein; Baharvand, Hossein

    2012-07-01

    A critical element in tissue engineering involves the fabrication of a three-dimensional scaffold. The scaffold provides a space for new tissue formation, supports cellular ingrowth, and proliferation and mimics many roles of the extracellular matrix. Poly(3-hydroxybutyrate) (PHB) is the most thoroughly investigated member of the polyhydroxyalkanoates (PHAs) family that has various degrees of biocompatibility and biodegradability for tissue engineering applications. In this study, we fabricated PHB scaffolds by utilizing electrospinning and salt-leaching procedures. The behavior of monkey epithelial kidney cells (Vero) and mouse mesenchymal stem cells (mMSCs) on these scaffolds was compared by the MTS assay and scanning electron microscopy. Additionally, this study investigated the mechanical and physical properties of these scaffolds by measuring tensile strength and modulus, dynamic contact angle and porosity. According to our results, the salt-leached scaffolds showed more wettability and permeability, but inferior mechanical properties when compared with nanofibrous scaffolds. In terms of cell response, salt-leached scaffolds showed enhanced Vero cell proliferation, whereas both scaffolds responded similarly in the case of mMSCs proliferation. In brief, nanofibrous scaffolds can be a better substrate for cell attachment and morphology. Copyright © 2012 Wiley Periodicals, Inc.

  4. 1064nm FT-Raman spectroscopy for investigations of plant cell walls and other biomass materials

    Science.gov (United States)

    Umesh P. Agarwal

    2014-01-01

    Raman spectroscopy with its various special techniques and methods has been applied to study plant biomass for about 30 years. Such investigations have been performed at both macro- and micro-levels. However, with the availability of the Near Infrared (NIR) (1064 nm) Fourier Transform (FT)-Raman instruments where, in most materials, successful fluorescence suppression...

  5. Small bandgap polymers for organic solar cells (polymer material development in the last 5 years)

    NARCIS (Netherlands)

    Kroon, Renee; Lenes, Martijn; Hummelen, Jan C.; Blom, Paul W.M.; Boer, Bert de

    2008-01-01

    During the last decade the field of polymer photovoltaics has seen a tremendous improvement in both device efficiency and understanding of the underlying physical processes. One has come to a point in which the prototypical large bandgap material system P3HT:PCBM is nearing optimal device

  6. 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.

  7. 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.

  8. 13th Workshop on Crystalline Silicon Solar Cell Materials and Processes: Extended Abstracts and Papers

    Energy Technology Data Exchange (ETDEWEB)

    Sopori, B. L.; Rand, J.; Saitoh, T.; Sinton, R.; Stavola, M.; Swanson, D.; Tan, T.; Weber, E.; Werner, J.; Al-Jassim, M.

    2003-08-01

    The 13th Workshop will provide a forum for an informal exchange of technical and scientific information between international researchers in the photovoltaic and relevant non-photovoltaic fields. It will offer an excellent opportunity for researchers in private industry and at universities to prioritize mutual needs for future collaborative research. The workshop is intended to address the fundamental aspects of impurities and defects in silicon: their properties, the dynamics during device processing, and their application for developing low-cost processes for manufacturing high-efficiency silicon solar cells. A combination of oral, poster, and discussion sessions will review recent advances in crystal growth, new cell structures, new processes and process characterization techniques, and cell fabrication approaches suitable for future manufacturing demands.

  9. The Hair Follicle: An Underutilized Source of Cells and Materials for Regenerative Medicine.

    Science.gov (United States)

    Kiani, Mehrdad T; Higgins, Claire A; Almquist, Benjamin D

    2018-04-09

    The hair follicle is one of only two structures within the adult body that selectively degenerates and regenerates, making it an intriguing organ to study and use for regenerative medicine. Hair follicles have been shown to influence wound healing, angiogenesis, neurogenesis, and harbor distinct populations of stem cells; this has led to cells from the follicle being used in clinical trials for tendinosis and chronic ulcers. In addition, keratin produced by the follicle in the form of a hair fiber provides an abundant source of biomaterials for regenerative medicine. In this review, we provide an overview of the structure of a hair follicle, explain the role of the follicle in regulating the microenvironment of skin and the impact on wound healing, explore individual cell types of interest for regenerative medicine, and cover several applications of keratin-based biomaterials.

  10. 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.

  11. 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

  12. Mandibular Reconstruction in Ameloblastoma Using Allogeneic Cord Stem Cells and Alloplastic Graft Material - Case Report.

    Science.gov (United States)

    Manimaran, K; Chandramohan, M; Kannan, R; Sankaranarayanan, S; Ravi, V R; Sharma, Rohini

    Ameloblastoma is a histologically benign odontogenic tumour and has a tendency of locally aggressive behaviour. This is second most prevalent odontogenic tumour and most common in the molar-ramus-angle region and surgical resection is only treatment option. In this article, we propose an innovative approach to deal with these cases by using alloplastic graft with cord stem cells. Over 2.5 years follow-up, we could demonstrate bone regeneration using this technique with no recurrence. To the best of our knowledge, this is the first report of successful regeneration of part of ramus and body of mandible using allogeneic cord stem cells in cases of Ameloblastoma.

  13. Electrocatalysts and their Supporting Materials for Proton Exchange Membrane Fuel Cells: Activity and Durability Studies

    DEFF Research Database (Denmark)

    Permyakova, Anastasia Aleksandrovna

    other methods. The thesis begins with an introduction in Chapter 1 providing an overview of fuel cells, their associated reaction mechanisms, catalysts and catalysts supports. Chapter 2 presents the theoretical background to the study including equipment and the techniques used to analyse the catalysts......This thesis describes investigations conducted exploring the activity, stability and durability of supported nano-particulate, bulk and thin film electrocatalysts used in proton exchange membrane fuel cells (PEMFCs). The effects of different factors and conditions on the reactions involved...

  14. Modeling materials and processes in hybrid/organic photovoltaics: from dye-sensitized to perovskite solar cells.

    Science.gov (United States)

    De Angelis, Filippo

    2014-11-18

    CONSPECTUS: Over the last 2 decades, researchers have invested enormous research effort into hybrid/organic photovoltaics, leading to the recent launch of the first commercial products that use this technology. Dye-sensitized solar cells (DSCs) have shown clear advantages over competing technologies. The top certified efficiency of DSCs exceeds 11%, and the laboratory-cell efficiency is greater than 13%. In 2012, the first reports of high efficiency solid-state DSCs based on organohalide lead perovskites completely revolutionized the field. These materials are used as light absorbers in DSCs and as light-harvesting materials and electron conductors in meso-superstructured and flat heterojunction solar cells and show certified efficiencies that exceed 17%. To effectively compete with conventional photovoltaics, emerging technologies such as DSCs need to achieve higher efficiency and stability, while maintaining low production costs. Many of the advances in the DSC field have relied on the computational design and screening of new materials, with researchers examining material characteristics that can improve device performance or stability. Suitable modeling strategies allow researchers to observe the otherwise inaccessible but crucial heterointerfaces that control the operation of DSCs, offering the opportunity to develop new and more efficient materials and optimize processes. In this Account, we present a unified view of recent computational modeling research examining DSCs, illustrating how the principles and simulation tools used for these systems can also be adapted to study the emerging field of perovskite solar cells. Researchers have widely applied first-principles modeling to the DSC field and, more recently, to perovskite-based solar cells. DFT/TDDFT methods provide the basic framework to describe most of the desired materials and interfacial properties, and Car-Parrinello molecular dynamics allow researchers the further ability to sample local minima and

  15. Atomic Layer Deposition on Porous Materials: Problems with Conventional Approaches to Catalyst and Fuel Cell Electrode Preparation

    Directory of Open Access Journals (Sweden)

    Tzia Ming Onn

    2018-03-01

    Full Text Available Atomic layer deposition (ALD offers exciting possibilities for controlling the structure and composition of surfaces on the atomic scale in heterogeneous catalysts and solid oxide fuel cell (SOFC electrodes. However, while ALD procedures and equipment are well developed for applications involving flat surfaces, the conditions required for ALD in porous materials with a large surface area need to be very different. The materials (e.g., rare earths and other functional oxides that are of interest for catalytic applications will also be different. For flat surfaces, rapid cycling, enabled by high carrier-gas flow rates, is necessary in order to rapidly grow thicker films. By contrast, ALD films in porous materials rarely need to be more than 1 nm thick. The elimination of diffusion gradients, efficient use of precursors, and ligand removal with less reactive precursors are the major factors that need to be controlled. In this review, criteria will be outlined for the successful use of ALD in porous materials. Examples of opportunities for using ALD to modify heterogeneous catalysts and SOFC electrodes will be given.

  16. Alternative perovskite materials as a cathode component for intermediate temperature single-chamber solid oxide fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Gaudillere, Cyril; Olivier, Louis; Vernoux, Philippe; Farrusseng, David [Universite Lyon 1, CNRS, UMR 5256, IRCELYON, Institut de recherches sur la catalyse et l' environnement de Lyon, 2 avenue Albert Einstein, F-69626 Villeurbanne (France); Zhang, Chunming; Shao, Zongping [State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, No 5 Xin Mofan Road, Nanjing 210009 (China)

    2010-08-01

    This paper exploits the suitability of three perovskite materials Ba{sub 0.5}Sr{sub 0.5}Co{sub 0.8}Fe{sub 0.2}O{sub 3-{delta}} (BSCF), GdBaCo{sub 2}O{sub 5+{delta}} (GBC) and Ba{sub 0.5}Sr{sub 0.5}Mn{sub 0.7}Fe{sub 0.3}O{sub 3-{delta}} (BSMF) as SOFC cathodes in the single-chamber configuration operating at the intermediate temperature range. TG analysis showed high thermal stability depending on the crystalline phases of the materials. The catalytic activity of these three materials for hydrocarbon conversion was investigated under a realistic feed, i.e. with hydrocarbon, oxygen, water and carbon dioxide. Electrochemical impedance spectroscopy of the various cathodes tested in symmetric cell configuration revealed a B-site dependence of the electrode catalytic activity for oxygen reduction. High temperature (1000 C) powder reactivity tests over a gadolinium doped-ceria (CGO) and perovskite cathode revealed excellent chemical compatibility of BSMF and CGO. Catalytic tests associated with thermal and structural characterization attest to the suitability of these materials in the single-chamber configuration. (author)

  17. Alternative perovskite materials as a cathode component for intermediate temperature single-chamber solid oxide fuel cell

    Science.gov (United States)

    Gaudillère, Cyril; Olivier, Louis; Vernoux, Philippe; Zhang, Chunming; Shao, Zongping; F