Growth rate and superconducting properties of Gd-Ba-Cu-O bulk superconductors melt processed in air

A generic Mg-doped Nd-Ba-Cu-O seed crystal has been developed recently for the fabrication of any type of rare earth (RE) based (RE)-Ba-Cu-O single grain bulk superconductor in air. The new generic seed simplifies significantly the top seeded melt growth (TSMG) process for light rare earth based (Nd, Sm, Gd, or mixed rare earth elements) bulk superconductors, in particular. GdBCO single grains have been fabricated successfully in air using the new seed in a cold-seeding process. In this study, precursor powders were enriched with different amounts of BaO2 to investigate the extent of substitution of Gd for Ba in the Gd1+xBa2-xCu3O7-delta solid solution phase. The growth process of large single grains in air was investigated at various growth temperatures under isothermal processing conditions. Crystal growth rate as a function of under-cooling and BaO2 content has been determined from these experiments. The spatial variation of Tc and transition temperature width for applied field aligned along the a/b and c-axis of grains fabricated with different BaO2 content has also been investigated in order to understand the extent of the formation of Gd/Ba solid solution with varying growth temperature and precursor composition. These results have been used to establish the optimum conditions for fabricating solid solution-free, large single grains of GdBCO in air

Superconducting properties of Gd-Ba-Cu-O single grains processed from a new, Ba-rich precursor compound

Gd-Ba-Cu-O (GdBCO) single grains have been previously melt-processed successfully in air using a generic Mg-Nd-Ba-Cu-O (Mg-NdBCO) seed crystal. Previous research has revealed that the addition of a small amount of BaO2 to the precursor powders prior to melt processing can suppress the formation of Gd/Ba solid solution, and lead to a significant improvement in superconducting properties of the single grains. Research into the effects of a higher Ba content on single grain growth, however, has been limited by the relatively small grain size in the earlier studies. This has been addressed by developing Ba-rich precursor compounds Gd-163 and Gd-143, fabricated specifically to enable the presence of greater concentrations of Ba during the melt process. In this study, we propose a new processing route for the fabrication of high performance GdBCO single grain bulk superconductors in air by enriching the precursor powder with these new Ba rich compounds. The influence of the addition of the new compounds on the microstructures and superconducting properties of GdBCO single grains is reported

A Convex Reconstruction Model for X-ray Tomographic Imaging with Uncertain Flat-fields

Classical methods for X-ray computed tomography are based on the assumption that the X-ray source intensity is known, but in practice, the intensity is measured and hence uncertain. Under normal operating conditions, when the exposure time is sufficiently high, this kind of uncertainty typically has a negligible effect on the reconstruction quality. However, in time- or dose-limited applications such as dynamic CT, this uncertainty may cause severe and systematic artifacts known as ring artifacts. By carefully modeling the measurement process and by taking uncertainties into account, we derive a new convex model that leads to improved reconstructions despite poor quality measurements. We demonstrate the effectiveness of the methodology based on simulated and real data sets.Comment: Accepted at IEEE Transactions on Computational Imagin

Bulk superconducting nano-composites with high critical currents

Flux pinning sites are most effective if their size is comparable to the superconducting coherence length, which is on the nano-meter scale for RE-Ba-Cu-O superconductors [RE = rare earth element]. Introducing nano-phase inclusions directly into the bulk superconducting material has only been partially successful to date, however, due primarily to the absence of chemically stable phases that can co-exist with RE-Ba-Cu-O without suppressing its key superconducting properties. We have identified novel isostructural phases based on (RE)2Ba4CuMOy (where M = W, Zr, Nb, Ag and Bi) and have fabricated successfully superconducting bulk nano-composites with a high current carrying capability. The average size of the nano-inclusions is observed to vary from 20 nm to 300 nm depending on element M. An observed improvement in Jc under low and high external magnetic fields at 77 K correlates directly with an increased density of nano-inclusions in the superconducting matrix

Properties of Mg-doped Nd-Ba-Cu-O generic seed crystals for the top seeded melt growth of (RE)-Ba-Cu-O bulk superconductors

We have recently developed a new generic seed crystal that has been used successfully to fabricate any oriented, single grain (RE)-Ba-Cu-O bulk superconductor by a cold seeding technique. In this paper we report the chemical, structural and microstructural properties of these seed crystals, including the variation of melting point, crystallographic parameters and volume fraction of Mg-rich inclusions in the Nd1 + xBa 2-x(Cu1-yMgy)3Oz matrix as a function of externally added MgO content. The influence of Mg-doping on the superconducting transition temperatures of YBCO grains fabricated using these seeds is investigated. Finally, an optimum MgO content of the generic seed that effectively controls the orientation of the seeded grain without compromising its superconducting properties is suggested from the many seed crystals fabricated with a wide range of Mg-rich addition

Pemantauan Virus Dengan Metode PCR (Polymerase Chain Reaction) Di Pantai Utara Jawa Timur [Monitoring Virus by PCR Method (Polymerase Chain Reaction) in North Coast, East Java]

The disease most dangerous for the cultivation activity is virus. Viruses are organisms subseluler that contain only nucleic acid (RNA or DNA) as genetic material. Koi Herpes Virus is one type of virus that causes mortality in cultured Cyprinids. KHV disease in Indonesia started in Blitar, East Java on March 2002 because the entry of imported koi fish that carry the virus KHV, while mortality prosentase could reach 80% - 85%, which causes loss of about 5 billion rupiah. In addition of KHV, there are several types of viral diseases in shrimp is White Spot Syndrome Virus (WSSV), Taura Syndrome Virus (TSV), dan Yellow Head Virus (YHV). Disease can cause losses in farming activities, such as WSSV. WSSV is an endemic disease since 1995. disease WSSV is exotic viral disease that attacks the shrimp monodon in 1998/1999 has resulted in decreased production of very large, so the Indonesian shrimp exports down 33,000 tons. Treatment of viral diseases is difficult because the virus resistant to certain antibiotics and chemical compounds. Therefore, prevention needs to be done, one through the monitoring activities conducted on the northern coast of East Java. The method implemented is monitoring in location and identification of viruses by PCR (Polymerase Chain Reaction). Monitoring in location includes water quality measurements and sampling. Identification of virus carried by IQ 2000TM. The identification procedure includes extraction, amplification and electrophoresis. Regional monitoring conducted on the northern coast of East Java includes Gresik, Lamongan, Tuban, Bangkalan, Sampang, Pamekasan, and Sumenep. Water quality at locations quite well. Results activities of monitoring on the northern coast of East Java is disease White Spot Syndrome Virus (WSSV) was found positive in several locations: Gresik, Lamongan and Tuban, while the virus Taura Syndrome Virus (TSV) and Yellow Head Virus (YHV) was not found at all locations . In tilapia, disease Koi Herpes Virus (KHV) was found positive in Tuban

Penerapan Metoda Taguchi Sebagai Usulan Perbaikan Kualitas Dalam Menghadapi Permasalahan Cacat Pada Produk Botol Morning Fresh (Lime) Isi 1000 Ml Di CV. Tunggal Jaya Plastics

One of the company efforts in increasing the sales volume of a product is with maintaining and increasing the quality of a product that have been produce by the company. Therefore, it is very important for the company to analyze and identify the problems that have been caused during the production process so the company can increase the quality of the product and productivity. Problems that cause during analyzing the defect product in production is how to arrange the optimal setting from each factor that significantly related so the company can minimize the defect product. This research was done at CV Tunggal Jaya Plastics and took the Morning Fresh (Lime) 1000 ml case product. Taguchi method is one of the methods that can be used to minimize the defect product by applying robust system for uncontrollable factors. The final result is to know factors that related significantly to the defect product and suggest the level of each factor therefore the defect product can be minimized

PENERAPAN AHP-SWOT DALAM PENINGKATAN FUNGSI JARINGAN IRIGASI D.I SENAKIN KOMPLEK KABUPATEN LANDAK

Kabupaten Landak sebagian besar penduduknya bekerja pada sektor pertanian. Sebagian besar sawah mendapat air dari jaringan irigasi yang pembiayaan operasi dan pemeliharaannya menggunakan anggaran Pemerintah Kabupaten Landak. Penurunan fungsi pada jaringan daerah irigasi (D.I) Senakin Komplek di Kabupaten Landak tidak dapat diabaikan, mengembalikan fungsi jaringan irigasi memerlukan anggaran yang tidak sedikit. Sehingga perlu adanya penetapan skala prioritas rehabilitasi jaringan daerah irigasi di D.I Senakin Komplek, dan menentukan ketersediaan dan kebutuhan air irigasi yang tersedia di D.I Senakin Komplek. Untuk menentukan skala prioritas rehabilitasi jaringan daerah irigasi di (D.I) Senakin Komplek, digunakan Metode Analitycal Hierarchy Process (AHP). AHP merupakan metode pengambilan keputusan dari masalah multi kriteria yang kompleks dengan menguraikan masalah tersebut menjadi suatu hirarki. Penulis dalam perhitungan AHP menggunakan Microsoft Ecxel. Dalam penelitian ini, untuk menentukan ketersediaan air dan kebutuhan air irigasi  penulis menganalisis data curah hujan dan data klimatologi dengan rentang waktu 15 tahun. Dari hasil penelitian terhadap 30 responden  yang mengisi kuisioner diperoleh hasil  prioritas pertama adalah perbaikan bagi sadap dengan bobot 0,340, prioritas kedua adalah perbaikan box bagi dengan bobot 0,291, prioritas ketiga adalah perbaikan saluran dengan bobot 0,242, dan prioritas keempat adalah perbaikan bendung dengan bobot 0,127. Dari hasil penelitian juga diperoleh hasil ketersediaan air dengan probabilitas 80% adalah 0,063 m³/detik pada Bulan September dan kebutuhan air sebesar 0,181 m³/detik pada bulan Septembe

How Social Media Marketing Influences Online Purchasing Decision: Study of the Viral Marketing and Perceived Ease of Use

Social media presents potentially seductive opportunities for new forms of communication and commerce between marketers and consumers. As advertisers typically want to find some way to follow their target audiences, many new media opportunities are presented to advertisers. The purpose of this study examined viral marketing and perceived ease of use influence on online purchasing decisions. This research is a quantitative research using non-probability sampling method with judgmental sampling technique. Data were collected using questionnaires from 110 respondents. The scale of measurement in this study was done using Likert scale and then analyzed using multiple linear regression. The results show that viral marketing and perceived ease of use have a significant influence on the online purchasing decision.     Keywords: viral marketing, perceived ease of use, social medi