58 research outputs found
Pressure dependent magnetic properties on bulk CrBr3 single crystals
No full textThe van der Waals class of materials offer an approach to two-dimensional magnetism as their spin fluctuations can be tuned upon exfoliation of layers. Moreover, it has recently been shown that spin-lattice coupling and long-range magnetic ordering can be modified with pressure in van der Waals materials. In this work, the magnetic properties of quasi two-dimensional CrBr3 are reported applying hydrostatic pressure. The application of pressure up to 0.844 GPa shows a 1.77% decrease in saturation magnetization with a decrease in the Curie temperature from 33.05 to 30.41 K. Density functional theory calculations with pressure up to 1 GPa show a reduction in volume and interplanar distance as pressure increases. To further understand the magnetic properties with applied pressure, the magnetocrystalline anisotropy energy (MAE) and exchange coupling parameter(s) (J) are calculated. There is small decrease in MAE and the first nearest neighbor interaction (J1) (U = 2.7 eV and J = 0.7 eV) is increasing with respect to increasing pressure. Overall, CrBr3 displays ferromagnetic interlayer coupling and the calculated exchange coupling and MAE parameters match well with the observations from the experimental work.This is a manuscript of an article published as Olmos, Rubyann, Shamsul Alam, Po-Hao Chang, Kinjal Gandha, Ikenna C. Nlebedim, Andrew Cole, Fazel Tafti, Rajendra R. Zope, and Srinivasa R. Singamaneni. "Pressure dependent magnetic properties on bulk CrBr3 single crystals." Journal of Alloys and Compounds 911 (2022): 165034.
DOI: 10.1016/j.jallcom.2022.165034.
Copyright 2022 Elsevier B.V.
Posted with permission.
DOE Contract Number(s): AC02-07CH11358
Pressure Induced Quantum Phase Transitions in Metallics Oxides and Pnictides
No full textQuantum phase transitions occur as a result of competing ground states. The focus of the present work is to understand quantum criticality and its consequences when the competition is between insulating and metallic ground states. Metal-insulator transitions are studied by means of electronic transport measurements and quantum critical points are approached by applying hydrostatic pressure in two different compounds namely EuIrO and FeCrAs. The former is a ternary metal oxide and the latter is a ternary metal pnictide.
A major component of this work was the development of the ultra-high pressure measurements by means of Anvil cells. A novel design is introduced which minimizes the alignment accessory components hence, making the cell more robust and easier to use.
EuIrO is a ternary metal oxide and a member of the pyrochlore iridate family. Resistivity measurements under pressure in moissanite anvil cells show the evolution of the ground state of the system from insulating to metallic. The quantum phase transition at GPa appears to be continuous. A remarkable correspondence is revealed between the effect of the hydrostatic pressure on EuIrO and the effect of chemical pressure by changing the R size in the RIrO series. This suggests that in both cases the tuning parameter controls the bandwidth of the iridium electrons. Moreover, hydrostatic pressure unveils a curious cross-over from incoherent to conventional metallic behaviour at a 150 K in the neighbourhood of , suggesting a connection between the high and low temperature phases. The possibility of a topological semi-metallic ground state, predicted in recent theoretical studies, is explained.
FeCrAs is a ternary metal pnictide with Fermi liquid specific heat and susceptibility behaviour but non-metallic non-Fermi liquid resistivity behaviour. Characteristic properties of the compound are explained and compared to those of superconducting pnictides. Antiferromagnetic (AFM) order sets in at K with the magnetic moments residing on the Cr site. Pressure measurements are carried out in moissanite and diamond anvil cells in order to suppress the AFM order and resolve the underlying electronic transport properties. While AFM order is destroyed by pressure, the non-metallic non-Fermi liquid behaviour is shown to be robust against pressure.Ph
Pressure Induced Quantum Phase Transitions in Metallics Oxides and Pnictides
No full textQuantum phase transitions occur as a result of competing ground states. The focus of the present work is to understand quantum criticality and its consequences when the competition is between insulating and metallic ground states. Metal-insulator transitions are studied by means of electronic transport measurements and quantum critical points are approached by applying hydrostatic pressure in two different compounds namely Eu2Ir22O 7 and FeCrAs. The former is a ternary metal oxide and the latter is a ternary metal pnictide.
A major component of this work was the development of the ultra-high pressure measurements by means of Anvil cells. A novel design is introduced which minimizes the alignment accessory components hence, making the cell more robust and easier to use.
Eu2Ir22O7 is a ternary metal oxide and a member of the pyrochlore iridate family. Resistivity measurements under pressure in moissanite anvil cells show the evolution of the ground state of the system from insulating to metallic. The quantum phase transition at Pc ∼ 6 GPa appears to be continuous. A remarkable correspondence is revealed between the effect of the hydrostatic pressure on Eu2Ir22O7 and the effect of chemical pressure by changing the R size in the R2Ir2O7 series. This suggests that in both cases the tuning parameter controls the t2g bandwidth of the iridium 5d electrons. Moreover, hydrostatic pressure unveils a curious cross-over from incoherent to conventional metallic behaviour at a T* > 150 K in the neighbourhood of Pc, suggesting a connection between the high and low temperature phases. The possibility of a topological semi-metallic ground state, predicted in recent theoretical studies, is explained.
FeCrAs is a ternary metal pnictide with Fermi liquid specific heat and susceptibility behaviour but non-metallic non-Fermi liquid resistivity behaviour. Characteristic properties of the compound are explained and compared to those of superconducting pnictides. Antiferromagnetic (AFM) order sets in at ∼125 K with the magnetic moments residing on the Cr site. Pressure measurements are carried out in moissanite and diamond anvil cells in order to suppress the AFM order and resolve the underlying electronic transport properties. While AFM order is destroyed by pressure, the non-metallic non-Fermi liquid behaviour is shown to be robust against pressure.Ph
Immunohistopathological findings in the lungs of calves naturally infected with Mycoplasma bovis
No full textHistology and immunohistochemistry were used to analyse the lesions and distribution of Mycoplasma bovis antigen in the lungs of 18 naturally infected calves. Microscopic examination of pneumonic lungs revealed two distinct patterns of necrosis and inflammation. The first pattern was observed in six of 18 (33.3%) calves in which microscopic lesions were characterized by large irregular areas of coagulative necrosis surrounded by a dense zone of degenerated neutrophils. Moderate amounts of mycoplasmal antigen were in the centre and periphery of these necrotic foci and, to a lesser extent, in mononuclear cells of the peribronchial lymphoid tissue. The second pattern was observed in 18 of 18 (100%) calves and consisted of rounded foci of caseous necrosis composed by granular eosinophilic material surrounded by a rim of granulation tissue. Large amounts of M. bovis antigen were detected in the centre and periphery of these necrotic foci and, to a lesser extent, in the peribronchial lymphoid tissue, and alveolar and interstitial macrophages. It was concluded that both caseous and coagulative necrosis of the lung parenchyma was primarily caused by M. bovis. Infection with M. bovis should be suspected in bovine necrotic bronchopneumonia, particularly in cases in which the pulmonary necrosis is part of a pyogranulomatous inflammation centred around airways. The pattern of caseous necrosis with pyogranulomatous inflammation is characteristic of M. bovis infection while the pattern of coagulative necrosis is similar to and must be differentiated from Mannheimia haemolytica and Haemophilus somnus infection.PT: J; CR: ADEGBOYE DS, 1995, J VET DIAGN INVEST, V7, P261 ADEGBOYE DS, 1995, J VET DIAGN INVEST, V7, P333 BENNETT RH, 1977, AM J VET RES, V38, P1731 BOOTHBY JT, 1988, CORNELL VET, V76, P188 BOUGHTON E, 1979, VET B, V49, P377 BRICE N, 2000, VET REC, V146, P643 BUCHVAROVA Y, 1989, ARCH EXP VET MED, V43, P685 DUNGWORTH DL, 1993, PATHOLOGY DOMESTIC A, P539 GEARY SJ, 1981, SCIENCE, V212, P1032 GOURLAY RN, 1985, RES VET SCI, V38, P377 GOURLAY RN, 1989, VET REC, V124, P420 HAINES DM, 1991, J VET DIAGN INVEST, V3, P101 HAINES DM, 2001, CAN VET J, V42, P857 HEWICKERTRAUTWEIN M, 2002, VET REC, V151, P699 KINDE H, 1993, J VET DIAGN INVEST, V5, P194 LOPEZ A, 1986, AM J VET RES, V47, P1283 LOPEZ A, 2001, SPECIAL VET PATHOLOG, P125 LOPEZ A, 2002, 18 PAN AM C VET SCI NICHOLAS RAJ, 2003, RES VET SCI, V74, P105 POTGIETER LND, 1995, VET CLIN N AM-FOOD A, V11, P501 RODRIGUEZ F, 1996, J COMP PATHOL, V115, P151 SHAHRIAR FM, 2002, CAN VET J, V43, P863 SLAUSON DO, 1990, MECH DIS TXB COMP GE THOMAS A, 2002, VET RES COMMUN, V26, P333; NR: 24; TC: 1; J9: J VET MED A-PHYSIOL PATHOL CL; PG: 5; GA: 818KGSource type: Electronic(1
Metastable Kitaev Magnets
No full textNearly two decades ago, Alexei Kitaev proposed a model for spin-1/2 particles with bond-directional interactions on a two-dimensional honeycomb lattice which had the potential to host a quantum spin-liquid ground state. This work initiated numerous investigations to design and synthesize materials that would physically realize the Kitaev Hamiltonian. The first generation of such materials, such as Na2IrO3, α-Li2IrO3, and α-RuCl3, revealed the presence of non-Kitaev interactions such as the Heisenberg and off-diagonal exchange. Both physical pressure and chemical doping were used to tune the relative strength of the Kitaev and competing interactions; however, little progress was made towards achieving a purely Kitaev system. Here, we review the recent breakthrough in modifying Kitaev magnets via topochemical methods that has led to the second generation of Kitaev materials. We show how structural modifications due to the topotactic exchange reactions can alter the magnetic interactions in favor of a quantum spin-liquid phase
A retrospective study of sporadic bovine abortions, stillbirths, and neonatal abnormalities in Atlantic Canada, from 1990 to 2001
No full textIn a retrospective study on 265 cases of sporadic bovine abortions, stillbirths, and neonatal deaths in Atlantic Canada (1990 to 2001), an etiological diagnosis was made in 117 cases (44.2%). The cases were divided into 2 groups: 234 abortions, and 31 stillbirths and neonatal deaths. Identified causes of abortion were bacteria (24.4%), fungi (6.8%), viruses (6.0%), protozoa (Neospora spp.) (2.1%), congenital anomalies (0.4%), and miscellaneous conditions (1.3%). In addition, placentitis without demonstrable infectious agents was observed in 17 (7.3%). Of the 31 cases of stillbirth and neonatal death, identified causes were dystocia (22.5%), congenital anomalies (22.5%), meconium aspiration syndrome (16.1%), and miscellaneous conditions (6.5%). No etiological diagnosis was made in 59% of abortions and 32.4% of stillbirths and neonatal deaths. The 3 most common identifiable causes of abortion in this study were bacterial, fungal, and viral infections
Characterization of the Magnetocaloric Effect in RMn6Sn6 including High Entropy Alloys
No full textWe present a comprehensive study of the magnetocaloric effect (MCE) in a
family of kagome magnets with formula RMn6Sn6 (R=Tb, Ho, Er, and Lu). These
materials have a small rare-earth content and tunable magnetic ordering, hence
they provide a venue to study the fundamentals of the MCE. We examine the
effect of different types of order (ferrimagnetic and antiferromagnetic) and
the presence of a metamagnetic transition on the MCE. We extend the study to
high-entropy rare-earth alloys of the family. Our results suggest several
guidelines for enhancing the MCE in tunable magnetic materials with a small
rare-earth content.Comment: Main Text: 14 pages, 5 figures, 1 Table; Supplemental: 5 pages, 4
figures, 1 table; Rewrites in version 2 in results and conclusio
Ormyrus orientalis Walker 1871
No full text9. Ormyrus orientalis Walker, 1871 Material examined: Esfahan, Esfahan, ex Acanthiophilus helianthi on safflower Carthamus oxycantha M.B, summer. 2008, (M.R. Sabzalian), 2 Ψ. East-Azarbaijan, Marand, Koshksaray, 28.ix. 2003, ex Tephritidae on Asteraceae, (H. Lotfalizadeh), 7 Ψ & 1 ɗ. East-Azarbaijan, Khosro-shahr, 1346m, N 37 º 58 ' 28 " & E 46 º 02' 55 ", 15.vii. 2008, Malaise trap, (H. Lotfalizadeh), 2 Ψ & 2 ɗ. Same locality, safflower experimental field, (H. Lotfalizadeh), 2 Ψ & 6 ɗ. Chahar-mahal-e-Bakhtiari, Gachsaran, summer. 2009, (K. Saeedi), 1 ɗ. Qazvin, Qazvin, swept from sugar beet, vi. 2007, (R. Arbab-Tafti), 1 Ψ. Qazvin, Alamut, summer 2009, pan trap, (B. Gharali), 1 Ψ. Khorasan-Razavi, Akhlamd, Chenaran, 1292m, apple orchard, N 36 º 38 ' 52 " & E 58 º 58 ' 7 ", 3.viii. 2009, (A. Hasani), 5 Ψ. Ormyrus orientalis has been previously reported from Iran (OILB 1971; Bouček 1977) and is a common and widely distributed species in the country. A wide host range has been reported for this species but in Iran it is mostly a parasitoid in fruit fly (Tephritidae) galls. We have seen specimens reared from capitulae of Asteraceae attacked by the fruit fly Urophora Robineau-Desvoidy, specimens reared from Acanthiophilus helianthi (Rossi) on safflower Carthamus oxycantha, and a single female swept in a field of sugar beet in Qazvin. Ormyrus orientalis is also associated with Cynipidae and Eurytomidae, and Movahedi-Fazel et al. (1998) reported it attacking the agromyzid fly Phytomyza orobanchiae Kaltenbach. It was collected commonly in the northwest of Iran (East-Azarbaijan Province) by Malaise trap and sweeping net. It is a common species in the Afrotropical, Oriental and Palaearctic regions (Noyes 2011).Published as part of Lotfalizadeh, Hosseinali, Askew, Richard R., Fuentes-Utrilla, Pablo & I, Majid Tavak O L, 2012, The species of Ormyrus Westwood (Hymenoptera: Ormyridae) in Iran with description of an unusual new species, pp. 34-44 in Zootaxa 3300 on page 42, DOI: 10.5281/zenodo.21078
Essays on antecedents and consequences of cloud computing capabilities in organizations: an empirical analysis of field data
No full textCloud computing is widely recognized as a potential disruptive paradigm that changes how IT is consumed and business is conducted in various industries. Managerial and academic literature has shown that cloud computing may benefit firms in various ways such as cost savings, fast project development, and business innovation. Nevertheless, there are many different interpretations and perceptions of cloud computing about how to better prepare for and use it in the information systems (IS) literature. A systematic analysis is necessary to clarify the equivocal issues around cloud computing and guide managers to better understand and utilize cloud computing in practice. This dissertation addresses several important relationships around cloud computing using theoretical models and empirical data as a representation of how the questions about cloud computing may be investigated in the IS literature and how the findings may benefit organizations in using cloud computing. Therefore, the dissertation comprises three connected chapters that address one important antecedent of cloud computing adoption – internal IT modularity within firms and two important consequences – firm performance and strategic alliance formation. It is found that in order to better prepare for cloud computing adoption, firm users can do something themselves by modularizing their internal IT systems. Firms also need to know whether and how cloud computing, after all, can benefit their firm performance or other activities such as strategic alliance formation. The findings show that cloud computing overall and its various specific cloud services may promote firm performance directly or complementarily with internal enterprise resources. Cloud computing and its specific cloud services may also exert different effects on strategic alliance formation. This dissertation systematically addresses the issues around cloud computing in the IS literature and sheds lights on how such a study can be applied to help managers and decision makers in industries to better understand and use cloud computing to achieve their business goals.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2018-08-01The student, Rui Guo, accepted the attached license on 2016-06-16 at 15:56.The student, Rui Guo, submitted this Dissertation for approval on 2016-06-16 at 16:01.This Dissertation was approved for publication on 2016-06-17 at 11:39.DSpace SAF Submission Ingestion Package generated from Vireo submission #9676 on 2016-11-10 at 12:24:35Made available in DSpace on 2016-11-10T18:39:10Z (GMT). No. of bitstreams: 3
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Outdoor assessment and modeling of dust deposition impact on optimal tilt angle and operating temperature of photovoltaics
No full text| openaire: EC/H2020/856602/EU//FINEST TWINSThe role of decentralization in decarbonizing the grid by focusing on the effective deployment of localized, roof-installed photovoltaic systems, is here considered by addressing the impact of dust in large cities. An analysis of 8 months of outdoor experimental data is conducted to study the impact of dust deposition on the optimal tilt angle and overall efficiency of photovoltaic systems. The accuracy of existing theoretical models for optimal tilt angle is tested, and the effect of a specific natural phenomenon, a dust storm, is also explored. The optimal tilt angle increased significantly to compensate for the reduced solar irradiance caused by dust accumulation on the modules, and after the dust storm the clean modules exhibited a higher temperature compared to the dusty modules. The degradation in efficiency due to dust accumulation is primarily attributed to the decreased solar radiation absorption, while temperature changes in the modules do not play any significant role for this parameter. It was also verified that the currently available theoretical models are not satisfactory in accounting for dust deposition. To address this, a preliminary correction model that incorporates the effects of dust into optimal tilt angle predictions is proposed. The obtained results are not only applicable to the specific testing location but can also be generalized to other regions affected by dust storms and to semi-arid climates more broadly, offering practical design guidance for installers and contributing to more reliable system design under real-world conditions.Peer reviewe
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