scholarly journals Effect of magnetic dipolar interactions on nanoparticle heating efficiency: Implications for cancer hyperthermia

2013 ◽  
Vol 3 (1) ◽  
Author(s):  
Luis C. Branquinho ◽  
Marcus S. Carrião ◽  
Anderson S. Costa ◽  
Nicholas Zufelato ◽  
Marcelo H. Sousa ◽  
...  
Keyword(s):  
Dipolar Interactions ◽  
Heating Efficiency ◽  
Cancer Hyperthermia

scholarly journals Erratum: CORRIGENDUM: Effect of magnetic dipolar interactions on nanoparticle heating efficiency: Implications for cancer hyperthermia

2014 ◽  
Vol 4 (1) ◽  
Author(s):  
Luis C. Branquinho ◽  
Marcus S. Carrião ◽  
Anderson S. Costa ◽  
Nicholas Zufelato ◽  
Marcelo H. Sousa ◽  
...  
Keyword(s):  
Dipolar Interactions ◽  
Heating Efficiency ◽  
Cancer Hyperthermia

scholarly journals Role of zinc substitution in magnetic hyperthermia properties of magnetite nanoparticles: interplay between intrinsic properties and dipolar interactions

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Yaser Hadadian ◽  
Ana Paula Ramos ◽  
Theo Z. Pavan
Keyword(s):  
Magnetic Nanoparticles ◽  
Magnetite Nanoparticles ◽  
Linear Response Theory ◽  
Magnetic Hyperthermia ◽  
Superior Performance ◽  
Dipolar Interactions ◽  
Intrinsic Properties ◽  
Specific Loss ◽  
Heating Efficiency ◽  
Specific Loss Power

AbstractOptimizing the intrinsic properties of magnetic nanoparticles for magnetic hyperthermia is of considerable concern. In addition, the heating efficiency of the nanoparticles can be substantially influenced by dipolar interactions. Since adequate control of the intrinsic properties of magnetic nanoparticles is not straightforward, experimentally studying the complex interplay between these properties and dipolar interactions affecting the specific loss power can be challenging. Substituting zinc in magnetite structure is considered as an elegant approach to tune its properties. Here, we present experimental and numerical simulation results of magnetic hyperthermia studies using a series of zinc-substituted magnetite nanoparticles (ZnxFe1-xFe2O4, x = 0.0, 0.1, 0.2, 0.3 and 0.4). All experiments were conducted in linear regime and the results were inferred based on the numerical simulations conducted in the framework of the linear response theory. The results showed that depending on the nanoparticles intrinsic properties, interparticle interactions can have different effects on the specific loss power. When dipolar interactions were strong enough to affect the heating efficiency, the parameter σ = KeffV/kBT (Keff is the effective anisotropy and V the volume of the particles) determined the type of the effect. Finally, the sample x = 0.1 showed a superior performance with a relatively high intrinsic loss power 5.4 nHm2kg−1.

Effects of inter- and intra-aggregate magnetic dipolar interactions on the magnetic heating efficiency of iron oxide nanoparticles

2016 ◽  
Vol 18 (16) ◽  
pp. 10954-10963 ◽  
Author(s):  
J. G. Ovejero ◽  
D. Cabrera ◽  
J. Carrey ◽  
T. Valdivielso ◽  
G. Salas ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Iron Oxide Nanoparticles ◽  
Biomedical Applications ◽  
Oxide Nanoparticles ◽  
Dipolar Interactions ◽  
Heating Efficiency ◽  
Magnetic Heating ◽  
Diagnostic Agents

Iron oxide nanoparticles have found biomedical applications as therapeutic and/or diagnostic agents.

THE MAGNETIC PROPERTIES OF A FERROFLUID WITH DIPOLAR INTERACTIONS

1985 ◽  
Vol 46 (C6) ◽  
pp. C6-283-C6-286
Author(s):  
A. Bradbury ◽  
S. Menear ◽  
R. W. Chantrell ◽  
K. O'Grady
Keyword(s):  
Magnetic Properties ◽  
Dipolar Interactions

Efficient Treatment of Fixed and Induced Dipolar Interactions

2000 ◽  
Vol 653 ◽  
Author(s):  
Celeste Sagui ◽  
Thoma Darden
Keyword(s):  
Molecular Dynamics ◽  
Md Simulations ◽  
Lagrangian Formalism ◽  
Dipolar Interactions ◽  
Time Step ◽  
Efficient Treatment ◽  
Particle Mesh Ewald ◽  
Fixed Charges ◽  
Self Consistency ◽  
Induced Dipoles

AbstractFixed and induced point dipoles have been implemented in the Ewald and Particle-Mesh Ewald (PME) formalisms. During molecular dynamics (MD) the induced dipoles can be propagated along with the atomic positions either by interation to self-consistency at each time step, or by a Car-Parrinello (CP) technique using an extended Lagrangian formalism. The use of PME for electrostatics of fixed charges and induced dipoles together with a CP treatment of dipole propagation in MD simulations leads to a cost overhead of only 33% above that of MD simulations using standard PME with fixed charges, allowing the study of polarizability in largemacromolecular systems.

3-D optimal design of laminated yoke of billet heater for rolling wire rod using ON/OFF method

2012 ◽  
Vol 61 (1) ◽  
pp. 115-123 ◽  
Author(s):  
Norio Takahashi ◽  
Shunsuke Nakazaki ◽  
Daisuke Miyagi ◽  
Naoki Uchida ◽  
Keiji Kawanaka ◽  
...  
Keyword(s):  
Optimal Design ◽  
Local Heating ◽  
Optimization Method ◽  
Optimal Topology ◽  
Field Problem ◽  
Heating Efficiency ◽  
Magnetic Devices ◽  
Wire Rod ◽  
Magnetic Recording Heads ◽  
Sensitivity Method

3-D optimal design of laminated yoke of billet heater for rolling wire rod using ON/OFF method The optimization method using the ON/OFF sensitivity analysis has an advantage that an epoch-making construction of magnetic circuit may be obtained. Therefore, it is attractive for designers of magnetic devices. We have already developed the ON/OFF method for the optimization of a static magnetic field problem, and the effectiveness is verified by applying it to the optimization of magnetic recording heads. In this paper, the ON/OFF sensitivity method is extended to the optimization of the eddy current problem using the adjoint variable. The newly developed ON/OFF method is applied to the determination of the optimal topology of the yoke of the billet heater for rolling wire rod. As a result, the optimal shape of yoke, which we could not imagine beforehand can be obtained. It is shown that the local heating of the yoke was reduced without decreasing the heating efficiency.

scholarly journals Aggregation affects optical properties and photothermal heating of gold nanospheres

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yiru Wang ◽  
Zhe Gao ◽  
Zonghu Han ◽  
Yilin Liu ◽  
Huan Yang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Cross Section ◽  
Laser Heating ◽  
Dipole Approximation ◽  
Gold Nanospheres ◽  
Extinction Cross Section ◽  
Heating Efficiency ◽  
Photothermal Heating ◽  
New Framework ◽  
Laser Calorimetry

AbstractLaser heating of gold nanospheres (GNS) is increasingly prevalent in biomedical applications due to tunable optical properties that determine heating efficiency. Although many geometric parameters (i.e. size, morphology) can affect optical properties of individual GNS and their heating, no specific studies of how GNS aggregation affects heating have been carried out. We posit here that aggregation, which can occur within some biological systems, will significantly impact the optical and therefore heating properties of GNS. To address this, we employed discrete dipole approximation (DDA) simulations, Ultraviolet–Visible spectroscopy (UV–Vis) and laser calorimetry on GNS primary particles with diameters (5, 16, 30 nm) and their aggregates that contain 2 to 30 GNS particles. DDA shows that aggregation can reduce the extinction cross-section on a per particle basis by 17–28%. Experimental measurement by UV–Vis and laser calorimetry on aggregates also show up to a 25% reduction in extinction coefficient and significantly lower heating (~ 10%) compared to dispersed GNS. In addition, comparison of select aggregates shows even larger extinction cross section drops in sparse vs. dense aggregates. This work shows that GNS aggregation can change optical properties and reduce heating and provides a new framework for exploring this effect during laser heating of nanomaterial solutions.

scholarly journals Enhancement of Parametric Effects in Polariton Waveguides Induced by Dipolar Interactions

2021 ◽  
Vol 126 (13) ◽  
Author(s):  
D. G. Suárez-Forero ◽  
F. Riminucci ◽  
V. Ardizzone ◽  
N. Karpowicz ◽  
E. Maggiolini ◽  
...  
Keyword(s):  
Dipolar Interactions ◽  
Parametric Effects

scholarly journals Study on External Gas-Assisted Mold Temperature Control with the Assistance of a Flow Focusing Device in the Injection Molding Process

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 965 ◽  
Author(s):  
Nguyen Truong Giang ◽  
Pham Son Minh ◽  
Tran Anh Son ◽  
Tran Minh The Uyen ◽  
Thanh-Hai Nguyen ◽  
...  
Keyword(s):  
Injection Molding ◽  
Temperature Control ◽  
Mold Temperature ◽  
Injection Molding Process ◽  
Melt Flow ◽  
Flow Focusing ◽  
Molding Process ◽  
Heating Efficiency ◽  
Flow Length ◽  
Insert Plate

In the injection molding field, the flow of plastic material is one of the most important issues, especially regarding the ability of melted plastic to fill the thin walls of products. To improve the melt flow length, a high mold temperature was applied with pre-heating of the cavity surface. In this paper, we present our research on the injection molding process with pre-heating by external gas-assisted mold temperature control. After this, we observed an improvement in the melt flow length into thin-walled products due to the high mold temperature during the filling step. In addition, to develop the heating efficiency, a flow focusing device (FFD) was applied and verified. The simulations and experiments were carried out within an air temperature of 400 °C and heating time of 20 s to investigate a flow focusing device to assist with external gas-assisted mold temperature control (Ex-GMTC), with the application of various FFD types for the temperature distribution of the insert plate. The heating process was applied for a simple insert model with dimensions of 50 mm × 50 mm × 2 mm, in order to verify the influence of the FFD geometry on the heating result. After that, Ex-GMTC with the assistance of FFD was carried out for a mold-reading process, and the FFD influence was estimated by the mold heating result and the improvement of the melt flow length using acrylonitrile butadiene styrene (ABS). The results show that the air sprue gap (h) significantly affects the temperature of the insert and an air sprue gap of 3 mm gives the best heating rate, with the highest temperature being 321.2 °C. Likewise, the actual results show that the height of the flow focusing device (V) also influences the temperature of the insert plate and that a 5 mm high FFD gives the best results with a maximum temperature of 332.3 °C. Moreover, the heating efficiency when using FFD is always higher than without FFD. After examining the effect of FFD, its application was considered, in order to improve the melt flow length in injection molding, which increased from 38.6 to 170 mm, while the balance of the melt filling was also clearly improved.

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