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Full-Text Articles in Engineering
Does The Critical Shields Stress For Sediment Transport Depend On Channel-Bed Slope?, Ishraq Alfadhli, Shu-Qing Yang, Muttucumaru Sivakumar
Does The Critical Shields Stress For Sediment Transport Depend On Channel-Bed Slope?, Ishraq Alfadhli, Shu-Qing Yang, Muttucumaru Sivakumar
Ishraq Hamdan Alfadhli
This paper investigates why the observed critical Shields stress for incipient sediment motion deviates from the Shields curve. This deviation is often described in the literature as due to measurement errors and non-uniformity of channel-bed slope or flows. On the contrary, this paper hypothesises the deviation as due to the presence of vertical velocity in open channel flows. We found that the existence of vertical velocity in non-uniform flows can lead to the deviation of critical shear stress from the standard Shield's diagram that is valid only in uniform flows, and the channel bed slope could not contribute to the …
Understanding The Factors Controlling The Removal Of Trace Organic Contaminants By White-Rot Fungi And Their Lignin Modifying Enzymes: A Critical Review, Shufan Yang, Faisal I. Hai, Long D. Nghiem, William E. Price, Felicity Roddick, Maria T. Moreira, Saleh F. Magram
Understanding The Factors Controlling The Removal Of Trace Organic Contaminants By White-Rot Fungi And Their Lignin Modifying Enzymes: A Critical Review, Shufan Yang, Faisal I. Hai, Long D. Nghiem, William E. Price, Felicity Roddick, Maria T. Moreira, Saleh F. Magram
William E. Price
White-rot fungi (WRF) and their lignin modifying enzymes (LME) can degrade a wide range of trace organic contaminants (TrOC), which are suspected to cause adverse health effects in humans and other biota. Recent studies have successfully applied either whole-cell WRF or their extracellular culture extract to remove TrOC from the aqueous phase. TrOC removal by a WRF system is dependent on a range of factors including molecular structure of the TrOC, fungal species and their specific LME, culture medium composition, and methods to enhance fungal degradation capacity; however, the specific relationships between these factors have not been systematically delineated. The …
Magnetic Field Processing To Enhance Critical Current Densities Of Mgb2 Superconductors, S X. Dou, Wai Kong Yeoh, Olga V. Shcherbakova, Josip Horvat, Jung Ho Kim, Alexey V. Pan, David Wexler, Yongqing Li, W X. Li, Z M. Ren, Paul G. Munroe, J Z. Cui
Magnetic Field Processing To Enhance Critical Current Densities Of Mgb2 Superconductors, S X. Dou, Wai Kong Yeoh, Olga V. Shcherbakova, Josip Horvat, Jung Ho Kim, Alexey V. Pan, David Wexler, Yongqing Li, W X. Li, Z M. Ren, Paul G. Munroe, J Z. Cui
Josip Horvat
A magnetic field of up to 12T was applied during the sintering process of pure MgB2 and carbon nanotube(CNT)dopedMgB2wires. The authors have demonstrated that magnetic field processing results in grain refinement, homogeneity, and enhancement in Jc(H) and Hirr. The extent of improvement in Jc increases with increasing field. The Jc for a 10T field processed CNTdoped sample increases by a factor of 3 at 10K and 8T and at 20K and 5T, respectively. Hirr for the 10T field processed CNTdoped sample reached 9T at 20K, which exceeded the best value of SiC dopedMgB2 at 20K. Magnetic field processing reduces the …
Understanding The Factors Controlling The Removal Of Trace Organic Contaminants By White-Rot Fungi And Their Lignin Modifying Enzymes: A Critical Review, Shufan Yang, Faisal Hai, Long Nghiem, William Price, Felicity Roddick, Maria Moreira, Saleh Magram
Understanding The Factors Controlling The Removal Of Trace Organic Contaminants By White-Rot Fungi And Their Lignin Modifying Enzymes: A Critical Review, Shufan Yang, Faisal Hai, Long Nghiem, William Price, Felicity Roddick, Maria Moreira, Saleh Magram
Faisal I Hai
White-rot fungi (WRF) and their lignin modifying enzymes (LME) can degrade a wide range of trace organic contaminants (TrOC), which are suspected to cause adverse health effects in humans and other biota. Recent studies have successfully applied either whole-cell WRF or their extracellular culture extract to remove TrOC from the aqueous phase. TrOC removal by a WRF system is dependent on a range of factors including molecular structure of the TrOC, fungal species and their specific LME, culture medium composition, and methods to enhance fungal degradation capacity; however, the specific relationships between these factors have not been systematically delineated. The …
Excess Mg Addition Mgb2 /Fe Wires With Enhanced Critical Current Density, Rong Zeng, Lin Lu, Wenxian Li, Jianli Wang, Dongqi Shi, Josip Horvat, S X. Dou, M Bhatia, M D Sumption, Edward W. Collings, Jaimoo Yoo, Mike Tomsic, M Rindfleisch
Excess Mg Addition Mgb2 /Fe Wires With Enhanced Critical Current Density, Rong Zeng, Lin Lu, Wenxian Li, Jianli Wang, Dongqi Shi, Josip Horvat, S X. Dou, M Bhatia, M D Sumption, Edward W. Collings, Jaimoo Yoo, Mike Tomsic, M Rindfleisch
Jianli Wang
MgB2 /Fe wires with 10 at. % excess Mg produced by in situ powder-in-tube processing werecompared to normal stoichiometric MgB2 /Fe wires prepared by the same method. It was found thatthe critical current density Jc and the irreversibility field (Hirr) were significantly enhanced forMgB2 /Fe wires with excess Mg. The transport Jc for 10 at. % Mg excess samples sintered at 800 degrees C, measured at a field of up to 14 T, increased by a factor of 2 compared to that for the normal MgB2 wires. The best Jc results for the 10 at. % Mg excess sample were …
Investigation Of The Critical Behavior In Mn0.94nb 0.06coge Alloy By Using The Field Dependence Of Magnetic Entropy Change, J C. Debnath, P Shamba, A M. Strydom, Jianli Wang, S X. Dou
Investigation Of The Critical Behavior In Mn0.94nb 0.06coge Alloy By Using The Field Dependence Of Magnetic Entropy Change, J C. Debnath, P Shamba, A M. Strydom, Jianli Wang, S X. Dou
Jianli Wang
The critical behaviour of Mn0.94Nb0.06CoGe alloy around the paramagnetic-ferromagnetic phase transition was studied based on the field dependence on magnetic entropy change. By using the obtained exponents, the modified Arrott plot is consistent with that by using conventional method. These critical exponents are confirmed by the Widom scaling relation. Based on these critical exponents, the magnetization, field and temperature data around Tc collapse into two curves obeying the single scaling equation MðH; e)¼ebf6(H/ebþc). The calculated critical exponents not only obey the scaling theory but also anastomose the deduced results from the Kouvel-Fisher method [J. S. Kouvel and M. E. Fisher, …
Significant Improvement In The Critical Current Density Of In Situ Mgb2 By Excess Mg Addition, R Zeng, L Lu, Jianli Wang, J Horvat, W Li, Dongqi Shi, S Dou, M Tomsic, M Rindfleisch
Significant Improvement In The Critical Current Density Of In Situ Mgb2 By Excess Mg Addition, R Zeng, L Lu, Jianli Wang, J Horvat, W Li, Dongqi Shi, S Dou, M Tomsic, M Rindfleisch
Jianli Wang
We present a detailed analysis of the effects of excess Mg on the lattice parameters, the critical temperature (Tc), the critical current (Jc), the irreversibility field (Hirr), and the upper critical field (Hc2) of MgB2 bulks and wires produced by an in situ solid-state reaction method and the powder-in-tube method, respectively. It was found that Jc, Hirr, and Hc2 were significantly enhanced for Mg excess samples. All these properties were highly sensitive to the processing temperature for Mg excess samples, while there was only a weak dependence on processing temperature for normal ones. The Tc variation for the 10% Mg …
Critical Magnetic Transition In Tbni2mn-Magnetization And Mossbauer Spectroscopy, Jianli Wang, S J. Campbell, S J. Kennedy, Rong Zeng, S. X. Dou, Guangheng Wu
Critical Magnetic Transition In Tbni2mn-Magnetization And Mossbauer Spectroscopy, Jianli Wang, S J. Campbell, S J. Kennedy, Rong Zeng, S. X. Dou, Guangheng Wu
Jianli Wang
The structural and magnetic properties of the TbNi2Mnx series (0.9 ≤ x ≤ 1.10) have been investigated using x-ray diffraction, field- and temperature-dependent ac magnetic susceptibility,DC magnetization (5-340 K; 0-5 T) and 57Fe Mössbauer spectroscopy (5-300 K). TbNi2Mnx crystallize in the MgCu2-type structure (space group Fd-3m). The additional contributions to the magnetic energy terms from transition metal-transition metal interactions (T-T) and rare earthtransition metal interactions (R-T) in RNi2Mn contribute to their increased magnetic ordering temperatures compared with RNi2 and RMn2. Both the lattice constant a and the Curie temperature TC exhibit maximal values at the x=1 composition indicating strong magnetostructural …
Identification Of Factors Limiting The Critical Current Density In Mgb2 _Xcx Superconductors At Low Magnetic Fields, Olga Shcherbakova, Alexey Pan, Jianli Wang, Andrey Shcherbakov, S. Dou, David Wexler
Identification Of Factors Limiting The Critical Current Density In Mgb2 _Xcx Superconductors At Low Magnetic Fields, Olga Shcherbakova, Alexey Pan, Jianli Wang, Andrey Shcherbakov, S. Dou, David Wexler
Jianli Wang
Structural analysis and electromagnetic measurements have been performed on a range of samples prepared by the liquid mixing approach to doping MgB2 are sugar, malic acid, and polycarbosilane. The results obtained have allowed us to clarify the contributions of the factors limiting critical current at low magnetic fields in doped MgB2.
The Magnetocaloric Effect And Critical Behaviour Of The Mn0.94ti0.06coge Alloy, P Shamba, Jianli Wang, J C. Debnath, S J. Kennedy, Rong Zeng, M F Md Din, F Hong, Z X. Cheng, A J. Studer, S X. Dou
The Magnetocaloric Effect And Critical Behaviour Of The Mn0.94ti0.06coge Alloy, P Shamba, Jianli Wang, J C. Debnath, S J. Kennedy, Rong Zeng, M F Md Din, F Hong, Z X. Cheng, A J. Studer, S X. Dou
Jianli Wang
Structural, magnetic and magnetocaloric properties of the Mn0.94Ti0.06CoGe alloy have been investigated using x-ray diffraction, DC magnetization and neutron diffraction measurements. Two phase transitions have been detected, at T-str = 235 K and T-C = 270 K. A giant magnetocaloric effect has been obtained at around Tstr associated with a structural phase transition from the low temperature orthorhombic TiNiSi-type structure to the high temperature hexagonal Ni2In-type structure, which is confirmed by neutron study. In the vicinity of the structural transition, at T-str, the magnetic entropy change, -Delta S-M reached a maximum value of 14.8 J kg(-1) K-1 under a magnetic …
Identification Of Factors Limiting The Critical Current Density In Mgb2 _Xcx Superconductors At Low Magnetic Fields, Olga V. Shcherbakova, Alexey V. Pan, Jianli Wang, Andrey Shcherbakov, S. X. Dou, David Wexler
Identification Of Factors Limiting The Critical Current Density In Mgb2 _Xcx Superconductors At Low Magnetic Fields, Olga V. Shcherbakova, Alexey V. Pan, Jianli Wang, Andrey Shcherbakov, S. X. Dou, David Wexler
Shi Xue Dou
Structural analysis and electromagnetic measurements have been performed on a range of samples prepared by the liquid mixing approach to doping MgB2 are sugar, malic acid, and polycarbosilane. The results obtained have allowed us to clarify the contributions of the factors limiting critical current at low magnetic fields in doped MgB2.
The Magnetocaloric Effect And Critical Behaviour Of The Mn0.94ti0.06coge Alloy, P Shamba, Jianli Wang, J C. Debnath, S J. Kennedy, Rong Zeng, M F Md Din, F Hong, Z X. Cheng, A J. Studer, S X. Dou
The Magnetocaloric Effect And Critical Behaviour Of The Mn0.94ti0.06coge Alloy, P Shamba, Jianli Wang, J C. Debnath, S J. Kennedy, Rong Zeng, M F Md Din, F Hong, Z X. Cheng, A J. Studer, S X. Dou
Shi Xue Dou
Structural, magnetic and magnetocaloric properties of the Mn0.94Ti0.06CoGe alloy have been investigated using x-ray diffraction, DC magnetization and neutron diffraction measurements. Two phase transitions have been detected, at T-str = 235 K and T-C = 270 K. A giant magnetocaloric effect has been obtained at around Tstr associated with a structural phase transition from the low temperature orthorhombic TiNiSi-type structure to the high temperature hexagonal Ni2In-type structure, which is confirmed by neutron study. In the vicinity of the structural transition, at T-str, the magnetic entropy change, -Delta S-M reached a maximum value of 14.8 J kg(-1) K-1 under a magnetic …
Peak Effect In The Critical Current Of Type Ii Superconductors With Strong Magnetic Vortex Pinning, X B. Xu, H Fangohr, X N. Xu, M Gu, Z H Wang, S M. Ji, Shichao Ding, Dongqi Shi, S. X. Dou
Peak Effect In The Critical Current Of Type Ii Superconductors With Strong Magnetic Vortex Pinning, X B. Xu, H Fangohr, X N. Xu, M Gu, Z H Wang, S M. Ji, Shichao Ding, Dongqi Shi, S. X. Dou
Shi Xue Dou
We perform 2D Langevin simulations studying the peak effect (PE) of the critical current taking into account the temperature dependence of the competing forces. We observe and report that the PE results from the competition of vortex-vortex interactions and vortex-pin interactions which have different temperature dependencies. The simulations reveal that the PE can take place only for certain pinning strengths, densities of pinning centres, and driving forces, which is in good agreement with experiments. No apparent vortex order-disorder transition is observed across the PE regime. In addition, the PE is a dynamical phenomenon, and thermal fluctuations can speed up the …
Investigation Of The Critical Behavior In Mn0.94nb 0.06coge Alloy By Using The Field Dependence Of Magnetic Entropy Change, J C. Debnath, P Shamba, A M. Strydom, Jianli Wang, S X. Dou
Investigation Of The Critical Behavior In Mn0.94nb 0.06coge Alloy By Using The Field Dependence Of Magnetic Entropy Change, J C. Debnath, P Shamba, A M. Strydom, Jianli Wang, S X. Dou
Shi Xue Dou
The critical behaviour of Mn0.94Nb0.06CoGe alloy around the paramagnetic-ferromagnetic phase transition was studied based on the field dependence on magnetic entropy change. By using the obtained exponents, the modified Arrott plot is consistent with that by using conventional method. These critical exponents are confirmed by the Widom scaling relation. Based on these critical exponents, the magnetization, field and temperature data around Tc collapse into two curves obeying the single scaling equation MðH; e)¼ebf6(H/ebþc). The calculated critical exponents not only obey the scaling theory but also anastomose the deduced results from the Kouvel-Fisher method [J. S. Kouvel and M. E. Fisher, …
Microscopic Role Of Carbon On Mgb2 Wire For Critical Current Density Comparable To Nbti, Jung Ho Kim, Sangjun Oh, Yoon-Uk Heo, Satoshi Hata, Hiroaki Kumakura, Akiyoshi Matsumoto, Masatoshi Mitsuhara, Seyong Choi, Yusuke Shimada, Minoru Maeda, Judith Macmanus-Driscoll, S X. Dou
Microscopic Role Of Carbon On Mgb2 Wire For Critical Current Density Comparable To Nbti, Jung Ho Kim, Sangjun Oh, Yoon-Uk Heo, Satoshi Hata, Hiroaki Kumakura, Akiyoshi Matsumoto, Masatoshi Mitsuhara, Seyong Choi, Yusuke Shimada, Minoru Maeda, Judith Macmanus-Driscoll, S X. Dou
Shi Xue Dou
Increasing dissipation-free supercurrent has been the primary issue for practical application of superconducting wires. For magnesium diboride, MgB2, carbon is known to be the most effective dopant to enhance high-field properties. However, the critical role of carbon remains elusive, and also low-field critical current density has not been improved. Here, we have undertaken malic acid doping of MgB2 and find that the microscopic origin for the enhancement of high-field properties is due to boron vacancies and associated stacking faults, as observed by high-resolution transmission electron microscopy and electron energy loss spectroscopy. The carbon from the malic acid almost uniformly encapsulates …
Upper Critical Field And Thermally Activated Flux Flow In Lafeaso1-Xfx, Mahboobeh Shahbazi, Xiaolin Wang, C Shekhar, O N. Srivastava, Z W. Lin, J G. Zhu, S. X. Dou
Upper Critical Field And Thermally Activated Flux Flow In Lafeaso1-Xfx, Mahboobeh Shahbazi, Xiaolin Wang, C Shekhar, O N. Srivastava, Z W. Lin, J G. Zhu, S. X. Dou
Shi Xue Dou
The magneto-resistance, critical current density, Jc, upper critical field, Hc2, and flux pinning properties of LaFeAsO1−xFx superconductors were investigated systematically by magnetic and magneto-transport measurements in the fields up to 13 T over a temperature range of 5–35 K. It was found that the Hc2 increased with increasing fluorine concentration up to x ≤ 0.15, while with higher fluorine doping, Hc2 decreased. A peak effect in the Jc as a function of field was observed at T Uo, scales as Uo/kB ∝ B−n with n = 0.13 for B n =− 0.68 for B > 1 T for LaFeAsO0.85F0.15.
Magnetic Field Processing To Enhance Critical Current Densities Of Mgb2 Superconductors, S X. Dou, Wai Kong Yeoh, Olga V. Shcherbakova, Josip Horvat, Jung Ho Kim, Alexey V. Pan, David Wexler, Yongqing Li, W X. Li, Z M. Ren, Paul G. Munroe, J Z. Cui
Magnetic Field Processing To Enhance Critical Current Densities Of Mgb2 Superconductors, S X. Dou, Wai Kong Yeoh, Olga V. Shcherbakova, Josip Horvat, Jung Ho Kim, Alexey V. Pan, David Wexler, Yongqing Li, W X. Li, Z M. Ren, Paul G. Munroe, J Z. Cui
Shi Xue Dou
A magnetic field of up to 12T was applied during the sintering process of pure MgB2 and carbon nanotube(CNT)dopedMgB2wires. The authors have demonstrated that magnetic field processing results in grain refinement, homogeneity, and enhancement in Jc(H) and Hirr. The extent of improvement in Jc increases with increasing field. The Jc for a 10T field processed CNTdoped sample increases by a factor of 3 at 10K and 8T and at 20K and 5T, respectively. Hirr for the 10T field processed CNTdoped sample reached 9T at 20K, which exceeded the best value of SiC dopedMgB2 at 20K. Magnetic field processing reduces the …
Quantitative Description Of Critical Current Density In Ybco Films And Multilayers, Alexey V. Pan, Serhiy Pysarenko, S X. Dou
Quantitative Description Of Critical Current Density In Ybco Films And Multilayers, Alexey V. Pan, Serhiy Pysarenko, S X. Dou
Shi Xue Dou
The vortex pinning model based on the presence of the large number of edge dislocations in high quality YBa2Cu3O7 (YBCO) films and multilayers has been refined. By introducing the pinning potential of a chain of individual edge dislocations, we have been able not only to describe the critical current density dependence on the applied magnetic field over its entire range, but also to extract the microstructural parameters in the films, such as inter-dislocation spacing and average domain size, without employing sophisticated microstructural analysis. The model applicability and its results have been verified with the help of microstructural characterization combined with …
Critical Current Degradation Caused By Winding Process Of Bi-2223/Ag Hts Wire In The Form Of A Coil, Jian X. Jin, S X. Dou, Hua-Kun Liu, T Hardono, Christopher D. Cook, C. Grantham
Critical Current Degradation Caused By Winding Process Of Bi-2223/Ag Hts Wire In The Form Of A Coil, Jian X. Jin, S X. Dou, Hua-Kun Liu, T Hardono, Christopher D. Cook, C. Grantham
Shi Xue Dou
High T, superconducting (HTS) (Bi,Pb)2Sr2Ca2 Cu3010+xA g-clad wire has potential for practical applications in the form of a coil or a winding. This HTS wire has strong magnetic field-dependent and mechanical strain-dependent critical currents, consequently it faces a severe problem of critical current degradation when it is used in the form of a coil. To design a winding with this conductor, the critical current degradation has to be identified with relation to the magnetic fields and the winding process. This is important to optimize an appropriate coil winding procedure using this HTS wire. A specially designed non-inductive sample has been …
Silicon Oil: A Cheap Liquid Additive For Enhancing In-Field Critical Current Density In Mgb2, Xiaolin Wang, Zhenxiang Cheng, S X. Dou
Silicon Oil: A Cheap Liquid Additive For Enhancing In-Field Critical Current Density In Mgb2, Xiaolin Wang, Zhenxiang Cheng, S X. Dou
Shi Xue Dou
In this work, the authors report on significant flux pinning enhancement in MgB2 that has been easily obtained using a liquid additive, silicon oil. MgB2 bulk samples with 0 up to 30 wt % silicon oil added were prepared by an in situ reaction. Results showed that the Si and C released from the decomposition of the silicon oil formed Mg2Si and substituted into B sites, respectively. Increasing the amount of the Si oil up to 15 wt % has resulted in the reduction of the lattice parameters, as well as Tc and R(300 K)/R(Tc) values, accompanied by a significant …
Angular Dependence Of Pinning Potential, Upper Critical Field, And Irreversibility Field In Underdoped Bafe1.9co0.1as2 Single Crystal, Mahboobeh Shahbazi, Xiaolin Wang, S R. Ghorbani, S. X. Dou, K Y. Choi
Angular Dependence Of Pinning Potential, Upper Critical Field, And Irreversibility Field In Underdoped Bafe1.9co0.1as2 Single Crystal, Mahboobeh Shahbazi, Xiaolin Wang, S R. Ghorbani, S. X. Dou, K Y. Choi
Shi Xue Dou
Underdoped BaFe1.9Co0.1As2 single crystal was studied by angular dependence of magneto-transport at fields up to 13 T over a wide range of temperature. Our results show that pinning potential, Uo, decreases slightly for h45 and remains constant for h45, while the upper critical field, Hc2, and the irreversibility field, Hirr, increase with h. According to anisotropic Ginzburg-Landau theory, the anisotropy was determined by scaling the resistivity under different magnetic fields below the superconducting critical temperature, Tc. Anisotropy, C, in the underdoped crystal is found to be temperature dependent and decreases from 2.1 to 1.8 for as T is reduced from …
Critical Magnetic Transition In Tbni2mn-Magnetization And Mossbauer Spectroscopy, Jianli Wang, S J. Campbell, S J. Kennedy, Rong Zeng, S. X. Dou, Guangheng Wu
Critical Magnetic Transition In Tbni2mn-Magnetization And Mossbauer Spectroscopy, Jianli Wang, S J. Campbell, S J. Kennedy, Rong Zeng, S. X. Dou, Guangheng Wu
Shi Xue Dou
The structural and magnetic properties of the TbNi2Mnx series (0.9 ≤ x ≤ 1.10) have been investigated using x-ray diffraction, field- and temperature-dependent ac magnetic susceptibility,DC magnetization (5-340 K; 0-5 T) and 57Fe Mössbauer spectroscopy (5-300 K). TbNi2Mnx crystallize in the MgCu2-type structure (space group Fd-3m). The additional contributions to the magnetic energy terms from transition metal-transition metal interactions (T-T) and rare earthtransition metal interactions (R-T) in RNi2Mn contribute to their increased magnetic ordering temperatures compared with RNi2 and RMn2. Both the lattice constant a and the Curie temperature TC exhibit maximal values at the x=1 composition indicating strong magnetostructural …