Heloisa N. Bordallo

ORCID: 0000-0003-0750-0553
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About
Contact & Profiles
Research Areas
  • Nuclear Physics and Applications
  • Magnetic and transport properties of perovskites and related materials
  • Crystallography and molecular interactions
  • Solid-state spectroscopy and crystallography
  • Inorganic Fluorides and Related Compounds
  • Advanced Condensed Matter Physics
  • Rare-earth and actinide compounds
  • High-pressure geophysics and materials
  • Soil and Unsaturated Flow
  • Clay minerals and soil interactions
  • NMR spectroscopy and applications
  • Luminescence Properties of Advanced Materials
  • Quantum, superfluid, helium dynamics
  • Molecular Spectroscopy and Structure
  • Concrete and Cement Materials Research
  • Advanced NMR Techniques and Applications
  • Protein Structure and Dynamics
  • Crystallization and Solubility Studies
  • Spectroscopy and Quantum Chemical Studies
  • Magnetism in coordination complexes
  • Atomic and Subatomic Physics Research
  • Building materials and conservation
  • Radiation Detection and Scintillator Technologies
  • Molecular spectroscopy and chirality
  • Hydrogen Storage and Materials

University of Copenhagen
2016-2025

Universidade Federal do Maranhão
2024

European Spallation Source
2014-2023

Deakin University
2017-2022

Monash University
2008-2020

Forschungszentrum Jülich
2009-2020

Heinz Maier-Leibnitz Zentrum
2020

Lawrence Berkeley National Laboratory
2020

Institute of Engineering
2020

University of South Florida
2017

An overview is provided of the 15 neutron beam instruments making up initial instrument suite European Spallation Source (ESS), and being made available to user community. The ESS source consists a high-power accelerator target station, providing unique long-pulse time structure slow neutrons. design considerations behind structure, moderator geometry layout are presented. 15-instrument two small-angle instruments, reflectometers, an imaging beamline, single-crystal diffractometers; one for...

10.1016/j.nima.2020.163402 article EN cc-by-nc-nd Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 2020-01-10

Abstract All organisms depend on specific proteins to compact and organize their genomes. In eukaryotes, histones fulfil this role, while bacterial chromosomes are shaped by nucleoid-associated (NAPs). Among its pleiotropic functions, the NAP Hfq plays a pivotal role in genome organization. study, we characterized structure of C-terminal extension Hfq, which mediates chromosomal compaction, DNA-bound state. Using an integrative approach that combined transmission electron microscopy, neutron...

10.1093/nar/gkaf169 article EN cc-by-nc Nucleic Acids Research 2025-02-27

Portland cement reacts with water to form an amorphous paste through a chemical reaction called hydration. In concrete the formation of pastes causes mix harden and gain strength rock-like mass. Within this process lies key remarkable peculiarity concrete: it is plastic soft when newly mixed, strong durable hardened. These qualities explain why one material, concrete, can build skyscrapers, bridges, sidewalks superhighways, houses, dams. The character determined by quality paste. Creep...

10.1021/jp062922f article EN The Journal of Physical Chemistry B 2006-08-22

The multiple energy states of water held by surfaces a clay mineral can be effectively probed with time-of-flight and fixed elastic window neutron scattering. We used these techniques to quantitatively differentiate types, including rotational translational diffusions, in Ca- Na-montmorillonite (SAz-1) charge-reduced preparations equilibrated at RH = 33% 55%, whose gravimetric contents are proportion their layer charge. Quasi-elastic scattering results revealed significant differences within...

10.1021/jp2072815 article EN The Journal of Physical Chemistry C 2012-02-06

The scattering of neutrons can be used to provide information on the structure and dynamics biological systems multiple length time scales. Pursuant a National Science Foundation-funded workshop in February 2018, recent developments this field are reviewed here, as well future prospects that expected given advances sources, instrumentation computational power methods. Crystallography, solution scattering, dynamics, membranes, labeling imaging examined. For extraction maximum information,...

10.1107/s2059798318017503 article EN Acta Crystallographica Section D Structural Biology 2018-12-01

The crystallographic and magnetic phase diagram of the $n=2$ layered manganite ${\mathrm{La}}_{2\ensuremath{-}2x}{\mathrm{Sr}}_{1+2x}{\mathrm{Mn}}_{2}{\mathrm{O}}_{7}$ in region $x>~0.5$ has been studied using temperature-dependent neutron powder diffraction. reveals a progression ordered structures generally paralleling that three-dimensional (3D) perovskites with similar electronic doping: A $(0.5<~x<~0.66)\ensuremath{\rightarrow}C$ $(0.75<~x<~0.90)\ensuremath{\rightarrow}G$...

10.1103/physrevb.62.15096 article EN Physical review. B, Condensed matter 2000-12-01

We report on the temperature dependence of crystal and magnetic structure layered colossal magnetoresistive manganite, ${\mathrm{La}}_{2\ensuremath{-}2x}{\mathrm{Sr}}_{1+2x}{\mathrm{Mn}}_{2}{\mathrm{O}}_{7}, x=0.3$. Neutron-diffraction measurements show that insulator-metal (IM) transition ${(T}_{\mathrm{IM}})$ at \ensuremath{\sim}100 K is accompanied by a ferromagnetic (FM) ordering spins within ${\mathrm{MnO}}_{6}$ bilayers (intrabilayer coupling), but with an antiferromagnetic coupling...

10.1103/physrevb.59.8695 article EN Physical review. B, Condensed matter 1999-04-01

Charge-lattice fluctuations are observed in the layered perovskite manganite LaSr2Mn2O7 by Raman spectroscopy as high 340 K and with decreasing temperature they become static form a charge ordered (CO) phase below TCO=210 K. In regime, superlattice reflections through neutron x-ray diffraction propagation vector (h+1/4,k-1/4,l). Crystallographic analysis of CO state demonstrates that degree orbital ordering this is weaker than three dimensional manganites. A TN=170K type-A antiferromagnetism...

10.1103/physrevb.61.15269 article EN Physical review. B, Condensed matter 2000-06-01

It has long been realized that cations play a critical role in the readsorption of water into interlayer region clay minerals. To explore possible differences dynamics related to presence clays, and examine its surface water, which plays prominent diffusion barriers comparative study was carried out highlight between montmorillonite halloysite. Whereas interact with can rehydrate after dehydration at temperature, halloysite no cations. Water is found both interlayers on these particles. In...

10.1021/jp803274j article EN The Journal of Physical Chemistry C 2008-08-16

Neutron scattering measurements on a bilayer manganite near optimal doping show that the short-range polaron correlations are completely dynamic at high T, but then freeze upon cooling to temperature T(*) approximately equal 310 K. This glass transition suggests paramagnetic/insulating state arises from an inherent orbital frustration inhibits formation of long-range orbital- and charge-ordered state. Upon further into ferromagnetic-metallic (T(C) = 114 K), where polarons melt, diffuse...

10.1103/physrevlett.89.036401 article EN Physical Review Letters 2002-07-01

We present the use of synthetic clay fluorohectorite (Fh) as a drug delivery system antibiotic ciprofloxacin. The adsorption capacity is very high, and Fh promotes controlled release without changing effectiveness toxicity.

10.1039/c7ra01384a article EN cc-by-nc RSC Advances 2017-01-01

Starch-based bioplastics offer a promising alternative to conventional plastics. However, they exhibit certain limitations, notably in terms of mechanical strength and barrier properties. These challenges could potentially be addressed through the incorporation nanocellulose as reinforcing agent. In this study, we fabricated bioplastic films using casting blending approach, employing highly linear pure amylose (AM) combination with cellulose nanofibers (CNF) or nanocrystals (CNC) at various...

10.3390/coatings13091573 article EN Coatings 2023-09-09

The crystal and magnetic structures of the spinel compounds ${\text{ZnCr}}_{2}{\text{S}}_{4}$ ${\text{ZnCr}}_{2}{\text{Se}}_{4}$ were investigated by high-resolution powder synchrotron neutron diffraction. exhibits a first-order phase transition at ${T}_{N}=21\text{ }\text{K}$ into an incommensurate helical structure. Magnetic fluctuations above ${T}_{N}$ are coupled to lattice as manifested negative thermal expansion. Both complex structure anomalous structural behavior can be related...

10.1103/physrevb.79.064423 article EN Physical Review B 2009-02-27

More than ever before, the world's increasing need for new infrastructure demands construction of efficient, sustainable and durable buildings, requiring minimal climate-changing gas-generation in their production. Maintenance-free "greener" building materials made from blended cements have advantages over ordinary Portland cements, as they are cheaper, generate less carbon dioxide more durable. The key improved performance blends (which substitute fine amorphous silicates cement) is related...

10.1038/srep02667 article EN cc-by-nc-nd Scientific Reports 2013-09-16

We report a combination of physical property and neutron scattering measurements for polycrystalline samples the one-dimensional spin-chain compound CoV${}_{2}$O${}_{6}$. Heat capacity show that an effective $S=1/2$ state is found at low temperatures magnetic fluctuations persist up to $\ensuremath{\sim}$6${T}_{N}$. Above ${T}_{N}=6.3$ K, susceptibility as function $T$ $H$ nearest-neighbor exchange ferromagnetic. In ordered state, we have discovered crossover from metamagnet with strong...

10.1103/physrevb.84.104425 article EN Physical Review B 2011-09-15

Incoherent Inelastic Neutron Scattering data and new infrared spectra were acquired in order to examine both the external internal vibrations crystalline L-alanine. For first time we observe a splitting of NH3+ torsional band below temperature approximately 220 K as well an overtone this band. The intensity these bands is strongly dependent on temperature. Birefringence depolarization measurements performed with single crystals reveal subtle breaking symmetry around perhaps involving...

10.1021/jp015615c article EN The Journal of Physical Chemistry A 2002-05-01

Incoherent inelastic neutron scattering spectra for the three crystalline polymorphs (α- P21/n, β- P21, γ- P31) of glycine (C2H5NO2) at temperatures between 5 and 300 K (using time-of-flight (ToF) spectrometer NEAT HMI) pressures from ambient up to 1 GPa ToF IN6 ILL) were measured. Significant differences in band positions their relative intensities density states (DoS) observed polymorphs, which can be related different intermolecular interactions. The mean-squared displacement, ⟨u2⟩(T),...

10.1021/jp8014723 article EN The Journal of Physical Chemistry B 2008-06-26

Interest in chiral versus racemic amino acid forms stems from their different solid-state properties associated to the packing arrangement that leads starkly physical behavior. Here we focus on dynamic of (l-form) and (dl-form) crystals serine, (C3H7NO3). Measuring incoherent inelastic neutron Raman scattering over a wide temperature range could assess subtle dynamical transition l-serine near 150 K. The difference l- dl-serine evidenced our spectroscopic studies is good agreement with CP(T)...

10.1021/ja073351n article EN Journal of the American Chemical Society 2007-08-21

Abstract The development of dental materials with improved properties and increased longevity can save costs minimize discomfort for patients. Due to their good biocompatibility, glass ionomer cements are an interesting restorative option. However, these have limited mechanical strength survive in the challenging oral environment. Therefore, a better understanding structure hydration process bring necessary further developments. Neutrons X-rays been used investigate highly complex pore...

10.1038/srep08972 article EN cc-by Scientific Reports 2015-03-10
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