Magnetohydrodynamic stagnation point on a Casson nanofluid flow over a radially stretching sheet

• Ganji Narender,
• Kamatam Govardhan and
• Gobburu Sreedhar Sarma

Beilstein J. Nanotechnol. 2020, 11, 1303–1315, doi:10.3762/bjnano.11.114

• fluid can be considered as a shear-thinning liquid, with infinite viscosity. On the other hand, when the stress rate approaches an infinite value the viscosity of the Casson fluid drops to zero [6]. Jam, tomato ketchup, honey, and concentrated fruit syrups are some quotidian examples of Casson fluids

An atomic force microscope integrated with a helium ion microscope for correlative nanoscale characterization

• Santiago H. Andany,
• Gregor Hlawacek,
• Stefan Hummel,
• Charlène Brillard,
• Mustafa Kangül and
• Georg E. Fantner

Beilstein J. Nanotechnol. 2020, 11, 1272–1279, doi:10.3762/bjnano.11.111

• down the sample using the z-piezo of the scanner, causing intermittent contact between the cantilever and the sample [25]. The maximum interaction force is computed and used as feedback by the controller, providing fine force control, reducing shear forces and thus preserving the tip and the sample [26

Magnetic-field-assisted synthesis of anisotropic iron oxide particles: Effect of pH

• Andrey V. Shibaev,
• Petr V. Shvets,
• Darya E. Kessel,
• Roman A. Kamyshinsky,
• Anton S. Orekhov,
• Sergey S. Abramchuk,
• Alexei R. Khokhlov and
• Olga E. Philippova

Beilstein J. Nanotechnol. 2020, 11, 1230–1241, doi:10.3762/bjnano.11.107

• ] in the presence of shear [40], etc. Almost all of these methods involve either the use of a template or a stabilizing agent to induce a directional one-dimensional growth of rod-like nanoparticles. The most common agents used are surfactants [11][21][23][26][37], polymers [27][36] and other additives

Revealing the local crystallinity of single silicon core–shell nanowires using tip-enhanced Raman spectroscopy

• Marius van den Berg,
• Ardeshir Moeinian,
• Arne Kobald,
• Yu-Ting Chen,
• Anke Horneber,
• Steffen Strehle,
• Alfred J. Meixner and
• Dai Zhang

Beilstein J. Nanotechnol. 2020, 11, 1147–1156, doi:10.3762/bjnano.11.99

• ) along the perimeter of a SiNW. The tip–sample distance is controlled by a shear-force feedback. For this purpose, the tip is mounted on an oscillating tuning fork, which experiences a phase shift of the oscillation upon approach. This phase shift is recorded with a lock-in amplifier and fed to a

• measured using the shear-force scanning function of our custom-built TERS setup. Eight TERS spectra were taken along the white arrow in Figure 5a over a length of 64 nm. The distance between the two sequential spectra is 8 nm. The spectra were acquired from bottom to top, with the black spectrum on the

• observed. a) A shear-force scanning probe microscopy topography image (250 × 250 nm2) of a silicon wire edge. The white arrow indicates the range and direction along which the Raman spectra in panels c and d were recorded. b) Location of the wire indicated on the 50 × 50 µm2 optical image by a white square

Vibration analysis and pull-in instability behavior in a multiwalled piezoelectric nanosensor with fluid flow conveyance

• Sayyid H. Hashemi Kachapi

Beilstein J. Nanotechnol. 2020, 11, 1072–1081, doi:10.3762/bjnano.11.92

• piezoelectric doubly curved nanoshells and orthotropic piezoelectric cylindrical nanoshells [23][24]. Wang utilized surface strain gradient elasticity to study a meticulous solution to the anti-plane shear problem of a circular elastic inhomogeneity [25]. Nami et al. utilized nonlocal elasticity theory and

• trigonometric shear deformation theory to investigate the static analysis of rectangular nanoplates [26]. The Gurtin–Murdoch surface theory is presented by Sigaeva et al. to study the universal model describing plane strain bending of a multilayered sector of a cylindrical tube [27]. Karimipour et al. presented

Wet-spinning of magneto-responsive helical chitosan microfibers

• Dorothea Brüggemann,
• Johanna Michel,
• Naiana Suter,
• Matheus Grande de Aguiar and
• Michael Maas

Beilstein J. Nanotechnol. 2020, 11, 991–999, doi:10.3762/bjnano.11.83

• helical fibers have the potential to be used as novel actuator systems or as magneto-responsive scaffolds for tissue engineering. Results and Discussion The viscous feedstock solutions containing 30 mg·mL−1 chitosan and 10 mg·mL−1 magnetic iron oxide particles (IOPs) showed a pronounced shear-thinning

• behavior. These results were corroborated by previous studies that used aqueous chitosan solutions for wet-spinning experiments [28][50]. A zero-shear viscosity of approximately 10 Pa·s (Figure 1A) was obtained. The yield point was not strongly pronounced at 0.1 Pa (Figure 1B), which explains why further

• rheometer (Malvern, Herrenberg, Germany) with a cone-plate geometry (1° angle and 50 mm diameter). The shear stress was measured at 20 °C with a stepwise increase in the shear rate and a one minute holding time at each shear-rate step. The size and zeta potential measurements were performed with 10 mg·mL−1

Extracting viscoelastic material parameters using an atomic force microscope and static force spectroscopy

• Cameron H. Parvini,
• M. A. S. R. Saadi and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2020, 11, 922–937, doi:10.3762/bjnano.11.77

• very stiff will have a high storage modulus and a low loss modulus. Such a sample will tend to store a majority of the applied load within its molecular structure and elastically return most or all of that energy when unloaded. Alternately, a medium that is susceptible to large shear forces (such as

Identification of physicochemical properties that modulate nanoparticle aggregation in blood

• Ludovica Soddu,
• Duong N. Trinh,
• Eimear Dunne,
• Dermot Kenny,
• Giorgia Bernardini,
• Ida Kokalari,
• Arianna Marucco,
• Marco P. Monopoli and
• Ivana Fenoglio

Beilstein J. Nanotechnol. 2020, 11, 550–567, doi:10.3762/bjnano.11.44

• . Dynamic platelet function assay (DPFA) The DPFA is a well-characterised real-time assay of platelet interaction with von Willebrand factor (VWF) under conditions of arterial shear [27][28][29]. The initial phases of platelet aggregation were assayed using the DPFA as previously described [25][26]. Briefly

• chamber at an arterial rate of shear (1500 s−1). Platelet translocation behaviour was recorded using real-time video microscopy at a rate of 19 frames per second. Image stacks were analysed by a custom-designed and validated software package [27]. The assay measurements obtained from this analysis include

• function assay (DPFA) was then used to investigate possible interference of the NPs on this process. This well-characterised assay monitors shear-mediated dynamic platelet interactions with surface-immobilised VWF. Adhesion was measured as the total number of platelets adhering to the substrate (Figure 11

Multilayer capsules made of weak polyelectrolytes: a review on the preparation, functionalization and applications in drug delivery

• Varsha Sharma and
• Anandhakumar Sundaramurthy

Beilstein J. Nanotechnol. 2020, 11, 508–532, doi:10.3762/bjnano.11.41

Nonclassical dynamic modeling of nano/microparticles during nanomanipulation processes

• Moharam Habibnejad Korayem,
• Ali Asghar Farid and
• Rouzbeh Nouhi Hefzabad

Beilstein J. Nanotechnol. 2020, 11, 147–166, doi:10.3762/bjnano.11.13

• , respectively, expressed by [16] where FT is the pushing force, τss, τrs and τrt are the shear strength of contact in sliding on the substrate and rolling on the substrate and particle, respectively, μ represents the friction constants, As and At are the substrate–particle and particle–tip contact area

• χij are the symmetric part of couple stress and curvature tensors, respectively. Also, the relation for couple stress and curvature tensors is written as [27] where l is the material length scale parameter for considering the size effects, and G is the shear modulus. The displacement fields for the

An investigation on the drag reduction performance of bioinspired pipeline surfaces with transverse microgrooves

• Weili Liu,
• Hongjian Ni,
• Peng Wang and
• Yi Zhou

Beilstein J. Nanotechnol. 2020, 11, 24–40, doi:10.3762/bjnano.11.3

• were undertaken to evaluate the drag reduction performance of these bionic pipelines. It was found that the vortex ‘cushioning’ and ‘driving’ effects produced by the vortexes in the microgrooves were the main reason for obtaining a drag reduction effect. The shear stress of the microgrooved surface was

• complex conditions. Besides, these active antidrag methods require extra energy or may complicate the devices, which limits their application in engineering. Pressure loss mainly derives from the shear stress of a fluid flowing across the surface of a pipeline. The wall shear stress is expressed as where

• τ is the shear stress (Pa), μ is the dynamic viscosity of the fluid (Pa∙s); and du/dy is the velocity gradient (1/s). According to Equation 1, changing the turbulent boundary layer state in the vicinity of the wall for a decreased velocity gradient is an essential and appropriate measure to reduce

Design of a nanostructured mucoadhesive system containing curcumin for buccal application: from physicochemical to biological aspects

• Sabrina Barbosa de Souza Ferreira,
• Gustavo Braga,
• Évelin Lemos Oliveira,
• Jéssica Bassi da Silva,
• Hélen Cássia Rosseto,
• Lidiane Vizioli de Castro Hoshino,
• Mauro Luciano Baesso,
• Wilker Caetano,
• Craig Murdoch,
• Helen Elizabeth Colley and
• Marcos Luciano Bruschi

Beilstein J. Nanotechnol. 2019, 10, 2304–2328, doi:10.3762/bjnano.10.222

• , 0.08% (w/w) CUR were evaluated at 25 and 37 °C (Figure 6). The nonlinear behavior to shear stress due to the shear rate (non-Newtonian), resulting in structural changes, was maintained even after the incorporation of CUR in the polymer blends. Moreover, the addition of CUR in binary polymeric systems

• did not lead to a change in flow rheological profiles at 25 °C, whereas a slight decrease of shear stress was observed for systems evaluated at 37 °C. In this way, CUR did not change the structuring of the system. Conversely, the increase in temperature leads to an increase in shear stress due to the

• thermoresponsive properties of the preparations. Low hysteresis areas and different yield values could be observed in a prominent way at 37 °C, in comparison to systems investigated at 25 °C. Consequently, these systems showed shear thinning behavior flow, which is considered to be a desirable characteristic for

Microfluidics as tool to prepare size-tunable PLGA nanoparticles with high curcumin encapsulation for efficient mucus penetration

• Nashrawan Lababidi,
• Valentin Sigal,
• Aljoscha Koenneke,
• Konrad Schwarzkopf,
• Andreas Manz and
• Marc Schneider

Beilstein J. Nanotechnol. 2019, 10, 2280–2293, doi:10.3762/bjnano.10.220

• sub-micrometer particles, because it is a simple and straightforward technique, without the involvement of any chemical additives, and also does not require harsh formulation parameters, such as high energy input or mechanical shear stress (e.g., by sonification) [30][31]. Nonetheless, the preparation

High-tolerance crystalline hydrogels formed from self-assembling cyclic dipeptide

• Yongcai You,
• Ruirui Xing,
• Qianli Zou,
• Feng Shi and
• Xuehai Yan

Beilstein J. Nanotechnol. 2019, 10, 1894–1901, doi:10.3762/bjnano.10.184

• properties The rheological properties of hydrogels are key evaluation indicators for a variety of applications [50][51]. It is typically challenging for hydrogels based on linear peptides to maintain their original gel state for a long time or under shear force. Driven by a thermodynamic process, they tend

• hydrogel enhanced along with time. Strain-induced shear-thinning and self-healing abilities of the hydrogel were detected through continuous step changes of oscillatory strain between 500% and 1% (at a constant frequency of 1 rad s−1). Under a high magnitude strain (500%), the modulus of G’’ values

• fifth test cycle. As compared to that of 48 h, the C-WY hydrogel at 240 h showed a faster recovery speed. The strain-dependent oscillatory rheology results (at 240 h) showed a great anti-shear performance at stains ranging from about 0.1% to about 20%, indicating the shear-thinning behavior of the

Flexible freestanding MoS₂-based composite paper for energy conversion and storage

• Florian Zoller,
• Jan Luxa,
• Thomas Bein,
• Dina Fattakhova-Rohlfing,
• Daniel Bouša and
• Zdeněk Sofer

Beilstein J. Nanotechnol. 2019, 10, 1488–1496, doi:10.3762/bjnano.10.147

• flexible MoS2-based composite paper by high-energy shear force milling and simple vacuum filtration. This composite material combines high flexibility, mechanical strength and good chemical stability. Chronopotentiometric charge–discharge measurements were used to determine the capacitance of our paper

• the synthesis of a freestanding MoS2-based composite paper using a small addition of single-walled carbon nanotubes (SWCNTs) and shear-force milling in N-methyl-2-pyrrolidone (NMP). The paper was prepared simply by vacuum filtration of the slurry on top of a filter. The resulting material exhibits

• additional binders, conductive additives or a current collector. Results and Discussion Characterization of morphology, composition and mechanical properties The synthesized composite material based on MoS2 and SWCNTs was prepared by shear-force milling of MoS2 powder with SWCNTs. We then prepared a paper

Nanoscale spatial mapping of mechanical properties through dynamic atomic force microscopy

• Zahra Abooalizadeh,
• Leszek Josef Sudak and
• Philip Egberts

Beilstein J. Nanotechnol. 2019, 10, 1332–1347, doi:10.3762/bjnano.10.132

• mechanical properties of materials, the nanoscale mechanical properties, including elastic and shear moduli, can drastically differ from their bulk values. This results in opportunities to custom design or enhance bulk engineering materials with advances discovered through nanoscale interrogation [1]. Thus

• . Of course the advantages of dynamic AFM come at the expense that the lateral shear force between the tip and sample cannot be eliminated, making the technique inappropriate for weakly bonded samples. On the other hand, more variations of the experimental set up are possible for AFM, such as ultrahigh

Direct growth of few-layer graphene on AlN-based resonators for high-sensitivity gravimetric biosensors

• Jimena Olivares,
• Teona Mirea,
• Lorena Gordillo-Dagallier,
• Bruno Marco,
• José Miguel Escolano,
• Marta Clement and
• Enrique Iborra

Beilstein J. Nanotechnol. 2019, 10, 975–984, doi:10.3762/bjnano.10.98

• reached during the CVD growth of graphene (up to 650 °C). The active AlN films, purposely grown with the c-axis tilted, effectively excite shear modes displaying excellent in-liquid performance, with electromechanical coupling and quality factors of around 3% and 150, respectively, which barely vary after

• functionalization schemes also play an essential role. In fact, for a given design, the sensitivity not only depends on the density of the attached active receptors, but also on their distance to the device surface. For example, the interaction length of shear-mode resonators operating in liquid appears to be

• and patterned over the top electrode of the shear-mode SMRs. The active area of the resonators was subsequently functionalized using both covalent and non-covalent schemes that ended with the successful detection of antibodies without significant worsening of the resonator performance. Opposite to

Outstanding chain-extension effect and high UV resistance of polybutylene succinate containing amino-acid-modified layered double hydroxides

• Adam A. Marek,
• Vincent Verney,
• Christine Taviot-Gueho,
• Grazia Totaro,
• Laura Sisti,
• Annamaria Celli and
• Fabrice Leroux

Beilstein J. Nanotechnol. 2019, 10, 684–695, doi:10.3762/bjnano.10.68

• investigated and compared to filler-free PBS as well as LDH Mg2Al/nitrate as references. Both organo-modified LDHs exhibited a remarkable chain-extension effect for PBS with an outstanding increase in the zero-shear viscosity η0 for PBS–Mg2Al/PHE (two order of magnitude increase as compared to filler-free PBS

• sweeps from 0.1 to 100 rad s−1 and the gap between plates set at 1 mm. In all cases, the oscillatory shear stress amplitude was checked to ensure that measurements were performed inside the linear viscoelastic domain. The storage modulus (G’), loss modulus (G”) and tan δ (ratio of G” and G’) were

• fitting and extrapolation of the Cole–Cole representation to the x-axis (η′ at η″ = 0), the Newtonian zero-shear viscosity η0 can be calculated using Equation 1, which reflects even small changes in molecular mass. The effect of 5 wt % Mg2Al LDH filler on the PBS chain extension is presented as η”–η’ Cole

Topochemical engineering of composite hybrid fibers using layered double hydroxides and abietic acid

• Liji Sobhana,
• Lokesh Kesavan,
• Jan Gustafsson and
• Pedro Fardim

Beilstein J. Nanotechnol. 2019, 10, 589–605, doi:10.3762/bjnano.10.60

• material. Both bleached and unbleached pulps further undergo refining. Refining is a process in which mechanical compression and shear forces are applied to the intact wet fiber network in order to increase the surface exposure and surface area. In addition, it opens up fibrils on the surface, which

Mechanical and thermodynamic properties of Aβ₄₂, Aβ₄₀, and α-synuclein fibrils: a coarse-grained method to complement experimental studies

• Adolfo B. Poma,
• Horacio V. Guzman,
• Mai Suan Li and
• Panagiotis E. Theodorakis

Beilstein J. Nanotechnol. 2019, 10, 500–513, doi:10.3762/bjnano.10.51

• molecular understanding. Our approach allows a comparison of diverse elastic properties based on different deformations , i.e., tensile (YL), shear (S), and indentation (YT) deformation. From our analysis, we find a significant elastic anisotropy between axial and transverse directions (i.e., YT > YL) for

• the requirement of a different experimental setup, namely, the more involved sonification method [34]. Moreover, the experimental calculation of the shear modulus (S) can be realised by suspending the fibril between two beams and pressing the free part against the indenter, which gives rise to the

• , shear, and indentation processes. Mechanical and thermodynamics characterization through a CG model In our previous work [36], we have constructed a computational protocol for performing several types of mechanical deformation in silico (Figure 3). Such processes can be carried out at constant speed or

Graphene–graphite hybrid epoxy composites with controllable workability for thermal management

• Idan Levy,
• Eyal Merary Wormser,
• Maxim Varenik,
• Matat Buzaglo,
• Roey Nadiv and
• Oren Regev

Beilstein J. Nanotechnol. 2019, 10, 95–104, doi:10.3762/bjnano.10.9

• ) operated in cone and plate arrangements (stainless steel cone, with a 40 mm diameter and a 4° cone angle) at 25 °C. The shear rate was swept between 0.01–100 1/s, and each measurement was performed at steady-state flow at a shear rate of 0.01 1/s to extract the viscosity [51][68]. Functional thermal

• ). Single-filler composites: (a) TC and (b) viscosity and relative viscosity as functions of filler type and volume fraction at constant shear rate (0.1 1/s) and temperature of 25 °C. Each graph displays the fitting parameters. The solid lines in (a) are fits to the ROM model (Equation 1), and those in (b

• (at constant shear rate 0.1 [1/s], T = 25 °C) as a function of the graphite volume fraction. Each color represents a different constant GNP volume percent. The lines in (a) are fits to the ROM model (Equation 1), and those in (b), to the modified K–D model (Equation 2). The fitting parameters are

Pull-off and friction forces of micropatterned elastomers on soft substrates: the effects of pattern length scale and stiffness

• Peter van Assenbergh,
• Marike Fokker,
• Julian Langowski,
• Jan van Esch,
• Marleen Kamperman and
• Dimitra Dodou

Beilstein J. Nanotechnol. 2019, 10, 79–94, doi:10.3762/bjnano.10.8

• are present is referred to as the elastocapillary length l, which is defined as l = γ/μ, where γ is the surface tension of the substrate and μ is the elastic shear modulus of the substrate [26]. If the length scale of the microscale features is in the order of the elastocapillary length, indentation

• PVA-18, respectively. The elastocapillary length of PVA (defined as l = γPVA/μPVA [26], with surface tension γPVA ≈ 50 kPa [32] and elastic shear modulus μPVA ≈ 12 kPa for PVA-12) is in the order of 400 nm. Similarly, the elastocapillary length of PVA-18 is in the order of 300 nm. Pull-off forces of

A comparison of tarsal morphology and traction force in the two burying beetles Nicrophorus nepalensis and Nicrophorus vespilloides (Coleoptera, Silphidae)

• Liesa Schnee,
• Benjamin Sampalla,
• Josef K. Müller and
• Oliver Betz

Beilstein J. Nanotechnol. 2019, 10, 47–61, doi:10.3762/bjnano.10.5

• of pulling is well known in the attachment systems of insects, spiders and geckos [41]. Whereas in smooth systems, directionality results from a drop in contact area attributable to the flexibility of the pad, in hairy systems, both the contact area of each single hair and the higher shear stress

• local release might support shear-induced adhesion [46] and help to dose the secretion economically. In terms of the biological role, the higher attachment force in the pull direction might help the animals to climb effectively on a variety of structures such as plants and fur and might enable the males

• secretion in N. nepalensis compared with that of N. vespilloides [3]. Since under the dynamics of friction regimes, the generated shear stress is largely determined by the viscosity of the fluid [46], such higher viscosities might be responsible for the observed higher friction forces of N. nepalensis on

Contact splitting in dry adhesion and friction: reducing the influence of roughness

• Jae-Kang Kim and
• Michael Varenberg

Beilstein J. Nanotechnol. 2019, 10, 1–8, doi:10.3762/bjnano.10.1

• more easily to the surface waviness and by reducing the effective average peeling angle. These findings can be used to guide the development of biomimetic shear-actuated adhesives suitable for operation not only on smooth but also on rough surfaces. Keywords: biomimetics; contact splitting; gecko

• , regardless of the surface waviness, when the surface roughness increases. Second, splitting the wall-shaped microstructure in parallel to the shear direction helps to mitigate the negative effect of the increasing surface unevenness by allowing the split microstructure to adapt more easily to the surface

• waviness as well as by allowing it to reduce the effective average peeling angle. These findings can guide the development of biomimetic shear-actuated adhesives that are suitable for operation not only on smooth but also on rough surfaces. Experimental Microstructured surfaces with 140 µm high flaps

Ternary nanocomposites of reduced graphene oxide, polyaniline and hexaniobate: hierarchical architecture and high polaron formation

• Claudio H. B. Silva,
• Maria Iliut,
• Christopher Muryn,
• Christian Berger,
• Zachary Coldrick,
• Vera R. L. Constantino,
• Marcia L. A. Temperini and
• Aravind Vijayaraghavan

Beilstein J. Nanotechnol. 2018, 9, 2936–2946, doi:10.3762/bjnano.9.272

• -shear mixed at 7000 rpm for four times (15 min each). This procedure was used to avoid thermal degradation of the sample. The GO particles prepared by this method present flake sizes ranging from 5 to 30 μm [14][17], which are remarkably larger in comparison to GO reported in literature obtained by