scholarly journals Electrokinetics in Micro-channeled Cantilevers: Extending the Toolbox for Reversible Colloidal Probes and AFM-Based Nanofluidics

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Andreas Mark ◽  
Nicolas Helfricht ◽  
Astrid Rauh ◽  
Jinqiao Xue ◽  
Patrick Knödler ◽  
...  
Keyword(s):  
Essential Element ◽  
The State ◽  
Micro Channel ◽  
Force Measurements ◽  
Ion Conductance ◽  
Nanoparticle Deposition ◽  
Micro Channels ◽  
Wide Range ◽  
Colloidal Probes

AbstractThe combination of atomic force microscopy (AFM) with nanofluidics, also referred to as FluidFM, has facilitated new applications in scanning ion conductance microscopy, direct force measurements, lithography, or controlled nanoparticle deposition. An essential element of this new type of AFMs is its cantilever, which bears an internal micro-channel with a defined aperture at the end. Here, we present a new approach for in-situ characterization of the internal micro-channels, which is non-destructive and based on electrochemical methods. It allows for probing the internal environment of a micro-channeled cantilever and the corresponding aperture, respectively. Acquiring the streaming current in the micro-channel allows to determine not only the state of the aperture over a wide range of ionic strengths but also the surface chemistry of the cantilever’s internal channel. The high practical applicability of this method is demonstrated by detecting the aspiration of polymeric, inorganic and hydrogel particles with diameters ranging from several µm down to 300 nm. By verifying in-situ the state of the aperture, i.e. open versus closed, electrophysiological or nano-deposition experiments will be significantly facilitated. Moreover, our approach is of high significance for direct force measurements by the FluidFM-technique and sub-micron colloidal probes.

scholarly journals Towards an Understanding of Crystallization by Attachment

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 463
Author(s):  
Haihua Pan ◽  
Ruikang Tang
Keyword(s):  
Capillary Condensation ◽  
Force Measurements ◽  
Force Microscopy ◽  
Physical Conditions ◽  
Driving Mechanisms ◽  
Atomic Force ◽  
Wide Range ◽  
Dynamics Simulations ◽  
Hydration Layers

Crystallization via particle attachment was used in a unified model for both classical and non-classical crystallization pathways, which have been widely observed in biomimetic mineralization and geological fields. However, much remains unknown about the detailed processes and driving mechanisms for the attachment. Here, we take calcite crystal as a model mineral to investigate the detailed attachment process using in situ Atomic Force Microscopy (AFM) force measurements and molecular dynamics simulations. The results show that hydration layers hinder the attachment; however, in supersaturated solutions, ionic bridges are formed between crystal gaps as a result of capillary condensation, which might enhance the aggregation of calcite crystals. These findings provide a more detailed understanding of the crystal attachment, which is of vital importance for a better understanding of mineral formation under biological and geological environments with a wide range of chemical and physical conditions.

Experimental Studies of Pressure Drop and Flow Instability in Evaporative Micro-Channels

2008 ◽  
Author(s):  
Hee Joon Lee ◽  
Dongyao Liu ◽  
Shi-Chune Yao
Keyword(s):  
Pressure Drop ◽  
Flow Instability ◽  
Experimental Studies ◽  
Bond Number ◽  
Effective Length ◽  
Instability Criterion ◽  
Micro Channel ◽  
Micro Channels ◽  
Wide Range ◽  
Channel Systems

Experiments were conducted on evaporative micro-channel systems of water, containing 48 parallel channels of 353 μm hydraulic diameter. The general correlation of two-phase pressure drop for an initial design purpose of evaporative micro-channel systems reported in [1] has been validated. For the water boiling in micro-channels, flow instability was observed. The instability criterion, proposed by Kandlikar [2], is able to predict the water experimental results. However, further examination of his criterion revealed that it can not predict the results of Brutin and Tadrist’s data of n-pentane. This is because the Bond number of water is 0.01, but 0.33 for n-pentane. As a result, the growing bubble of n-pentane may not cover the whole length of the micro-channel. A general expression of the effective length of squeezed bubbles in micro-channel was established for fluids at a wide range of Bond number. Using this proposed effective length, the Brutin and Tadrist’s experimental instability data can also be predicted satisfactorily.

Generalized Two-Phase Pressure Drop and Heat Transfer Correlations in Evaporative Micro/Mini-Channels

2007 ◽  
Author(s):  
Hee Joon Lee ◽  
Dongyao Liu ◽  
Shi-Chune Yao ◽  
Y. Alyousef
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Bond Number ◽  
Micro Channel ◽  
Two Phase ◽  
Working Fluids ◽  
Operational Conditions ◽  
Micro Channels ◽  
Wide Range ◽  
Existing Data

Existing data base and correlations in literature on the micro-channel pressure drop and heat transfer are reviewed. None of the existing correlations can cover the wide range of working fluids, operational conditions and different microchannel dimensions. The importance of the Bond number, which relates the nominal bubble dimension or capillary parameter with the channel size, is revealed. Using the Bond number, improved correlations of pressure drop and heat transfer are established. The new correlations predict the existing data well over wide ranges of working fluids, operational conditions and dimensions of micro-channels. Furthermore, Bond number could be used as a criterion to classify a flow path as a micro-channel or conventional macro-channel.

3D Numerical Analysis of Velocity Profiles of PD, EO and Combined PD-EO Flows Through Microchannels

2006 ◽  
Author(s):  
Shahrzad Yazdi ◽  
Reza Monazami ◽  
Mahmoud A. Salehi
Keyword(s):  
Electric Field ◽  
External Electric Field ◽  
Charge Distribution ◽  
Three Dimensional ◽  
Flow Patterns ◽  
Ionic Concentration ◽  
Micro Channel ◽  
Micro Channels ◽  
Wide Range ◽  
Pressure Driven

In this paper, a three-dimensional numerical model is developed to analyze flow characteristics of pressure driven, electroosmotic and combined pressure driven-electroosmotic flows through micro-channels. The governing system of equations consists of the electric-field and flow-field equations. The solution procedure involves three steps. The net charge distribution on the cross section of the micro-channel is computed by solving two-dimensional Poisson-Boltzmann equation using the finite element method. Then, using the computed fluid’s charge distribution, the magnitude of the resulting body force due to interaction of an external electric field with the charged fluid is calculated along the micro-channel. Finally, three dimensional Navier-Stokes equations are solved by considering the presence of the electro-kinetic body forces in the flow system for electroosmotic and combined pressure driven electroosmotic flow cases. The results reveal that the flow patterns for combined PD-EO cases are significantly different from the parabolic velocity profile of the laminar pressure-driven flow. The effect of the liquid bulk ionic concentration and the external electric field strength on flow patterns through the square-shaped micro-channels is also investigated over a wide range of external electric field strengths and bulk ionic concentration.

In-situ electrical-resistivity measurements in the high-voltage electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 68-69
Author(s):  
W. E. King
Keyword(s):  
Electrical Resistivity ◽  
Electron Microscope ◽  
High Voltage ◽  
Resistivity Measurements ◽  
Voltage Electron ◽  
High Voltage Electron Microscope ◽  
High Voltage Electron ◽  
Wide Range ◽  
Helium Gas

A side-entry type, helium-temperature specimen stage that has the capability of in-situ electrical-resistivity measurements has been designed and developed for use in the AEI-EM7 1200-kV electron microscope at Argonne National Laboratory. The electrical-resistivity measurements complement the high-voltage electron microscope (HVEM) to yield a unique opportunity to investigate defect production in metals by electron irradiation over a wide range of defect concentrations.A flow cryostat that uses helium gas as a coolant is employed to attain and maintain any specified temperature between 10 and 300 K. The helium gas coolant eliminates the vibrations that arise from boiling liquid helium and the temperature instabilities due to alternating heat-transfer mechanisms in the two-phase temperature regime (4.215 K). Figure 1 shows a schematic view of the liquid/gaseous helium transfer system. A liquid-gas mixture can be used for fast cooldown. The cold tip of the transfer tube is inserted coincident with the tilt axis of the specimen stage, and the end of the coolant flow tube is positioned without contact within the heat exchanger of the copper specimen block (Fig. 2).

Site specific agricultural soil management with the use of new technologies

2013 ◽  
Vol 16 (1) ◽  
pp. 59-67
Keyword(s):  
New Technologies ◽  
Digital Interface ◽  
Appropriate Treatment ◽  
Wide Range ◽  
Soil Variation ◽  
Soil Information ◽  
Remote Sensing Techniques ◽  
Agricultural Areas

<p>The Soil Science Institute of Thessaloniki produces new digitized Soil Maps that provide a useful electronic database for the spatial representation of the soil variation within a region, based on in situ soil sampling, laboratory analyses, GIS techniques and plant nutrition mathematical models, coupled with the local land cadastre. The novelty of these studies is that local agronomists have immediate access to a wide range of soil information by clicking on a field parcel shown in this digital interface and, therefore, can suggest an appropriate treatment (e.g. liming, manure incorporation, desalination, application of proper type and quantity of fertilizer) depending on the field conditions and cultivated crops. A specific case study is presented in the current work with regards to the construction of the digitized Soil Map of the regional unit of Kastoria. The potential of this map can easily be realized by the fact that the mapping of the physicochemical properties of the soils in this region provided delineation zones for differential fertilization management. An experiment was also conducted using remote sensing techniques for the enhancement of the fertilization advisory software database, which is a component of the digitized map, and the optimization of nitrogen management in agricultural areas.</p>

RESEARCH ON INVESTMENT AND INNOVATION ACTIVITY IN UKRAINE: TRENDS AND PROBLEMS

2018 ◽  
Vol 1 (01) ◽  
pp. 5-73
Author(s):  
Anatoliy Ivanovich Bogdanenko
Keyword(s):  
State Policy ◽  
Innovation System ◽  
State Regulation ◽  
The State ◽  
Innovation Activity ◽  
Legal Principles ◽  
Innovation Activities ◽  
Wide Range ◽  
Intellectual Potential ◽  
Innovation Processes

In the monograph the theoretical identification of concepts and categorical series of state regulation of investment-innovation processes are investigated; the directions of optimization of the state policy of innovation and investment development management in Ukraine are determined; the organizational and legal principles of the state regulation of development of intellectual potential of the population are substantiated; the areas of development and improvement of the national innovation system as an object of state policy are highlighted and assessed. The monograph will be interesting for scholars, lecturers, doctoral and graduate students, and will also be useful to practical politicians, journalists and media workers and a wide range of readers interested in investment and innovation activities.

THE VALUE OF LOVE IN THE SYSTEM OF FORMATION OF THE PROFESSIONAL MATURITY OF THE EDUCATOR

2020 ◽  
Vol 1 (10(79)) ◽  
pp. 12-18
Author(s):  
G. Bubyreva
Keyword(s):  
Russian Federation ◽  
The State ◽  
Educational Process ◽  
Wide Range ◽  
The Family ◽  
The Russian Federation ◽  
The Government ◽  
The Individual ◽  
The Right

The existing legislation determines the education as "an integral and focused process of teaching and upbringing, which represents a socially important value and shall be implemented so as to meet the interests of the individual, the family, the society and the state". However, even in this part, the meaning of the notion ‘socially significant benefit is not specified and allows for a wide range of interpretation [2]. Yet the more inconcrete is the answer to the question – "who and how should determine the interests of the individual, the family and even the state?" The national doctrine of education in the Russian Federation, which determined the goals of teaching and upbringing, the ways to attain them by means of the state policy regulating the field of education, the target achievements of the development of the educational system for the period up to 2025, approved by the Decree of the Government of the Russian Federation of October 4, 2000 #751, was abrogated by the Decree of the Government of the Russian Federation of March 29, 2014 #245 [7]. The new doctrine has not been developed so far. The RAE Academician A.B. Khutorsky believes that the absence of the national doctrine of education presents a threat to national security and a violation of the right of citizens to quality education. Accordingly, the teacher has to solve the problem of achieving the harmony of interests of the individual, the family, the society and the government on their own, which, however, judging by the officially published results, is the task that exceeds the abilities of the participants of the educational process.  The particular concern about the results of the patriotic upbringing served as a basis for the legislative initiative of the RF President V. V. Putin, who introduced the project of an amendment to the Law of RF "About Education of the Russian Federation" to the State Duma in 2020, regarding the quality of patriotic upbringing [3]. Patriotism, considered by the President of RF V. V. Putin as the only possible idea to unite the nation is "THE FEELING OF LOVE OF THE MOTHERLAND" and the readiness for every sacrifice and heroic deed for the sake of the interests of your Motherland. However, the practicing educators experience shortfalls in efficient methodologies of patriotic upbringing, which should let them bring up citizens, loving their Motherland more than themselves. The article is dedicated to solution to this problem based on the Value-sense paradigm of upbringing educational dynasty of the Kurbatovs [15].

Safety assessment of biological raw materials in the system of medicines quality assurance

2020 ◽  
pp. 63-72
Author(s):  
Yu. Olefir ◽  
E. Sakanyan ◽  
I. Osipova ◽  
V. Dobrynin ◽  
M. Smirnova ◽  
...  
Keyword(s):  
Raw Materials ◽  
State Level ◽  
The State ◽  
Spongiform Encephalopathy ◽  
Safety Standards ◽  
Wide Range ◽  
The Russian Federation ◽  
Key Aspects ◽  
First Time ◽  
Medicines Quality

The entry of a wide range of biotechnological products into the pharmaceutical market calls for rein-forcement of the quality, efficacy and safety standards at the state level. The following general monographs have been elaborated for the first time to be included into the State Pharmacopoeia of the Russian Federation, XIV edition: "Viral safety" and "Reduction of the risk of transmitting animal spongiform encephalopathy via medicinal products". These general monographs were elaborated taking into account the requirements of foreign pharmacopoeias and the WHO recommendations. The present paper summarises the key aspects of the monographs.

The development of the movement for the communist labour at the Tyumen shipbuilding plant in days of the seven-year plan (1959-1965): the experience of microhistorical study

2019 ◽  
Vol 5 (2) ◽  
pp. 153-172
Author(s):  
Sergey S. Pashin ◽  
Natalia S. Vasikhovskaya
Keyword(s):  
Political History ◽  
The State ◽  
Historical Narrative ◽  
Industrial Enterprise ◽  
State Archive ◽  
Wide Range ◽  
Archival Documents ◽  
History Of

The article is devoted to the study of the movement for communist labour at the Tyumen Shipbuilding Plant during the period of the seven-year plan (1959-1965). The authors seek to fill a historical narrative with the particular facts connected with the peculiarities and specifics of such phenomenon as the movement for communist labour. They consider it in the context of microhistory and as the most important element of production routine. The employees of the largest industrial enterprise of Soviet Tyumen&nbsp;— Shipbuilding Plant in concrete historical circumstances came under the spotlight of the authors. The submitted article is written with attraction of a wide range of archival documents, taken from the funds of the State Archive of the Tyumen Region and also funds of the State Archive of Socio-Political History of the Tyumen Region. Having studied the documents the authors come to conclusion that the movement for communist labour had little effect on the production progress of the plant employees.

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