scholarly journals Quest for improving service life of asphalt roads

2020 ◽  
Vol 4 ◽  
pp. 154-162
Author(s):  
Manfred N. Partl
Keyword(s):  
Service Life ◽  
Building Materials ◽  
Phase Change Materials ◽  
Material Design ◽  
Point Of View ◽  
Asphalt Pavements ◽  
Force Microscopy ◽  
The Road ◽  
Atomic Force ◽  
Materials Recycling

Selected results and initiatives in modern asphalt pavement research for increasing service life of asphalt pavements under the aspect of sustainability and multifunctional use of roads are summarized. Focus lies on innovative approaches and own experience, jointly elaborated during the last decades within the road engineering/sealing components lab at Empa and both the highway/railways engineering and building materials group at KTH. This includes material concepts and design as well as pavement system and construction aspects from an experimental and modelling point of view. It includes also the application of powerful experimental and computational tools, such as Atomic-Force-Microscopy (AFM), X-Ray-Computer-Tomography (CT), Digital-Imaging-Correlation (DIC) and Discrete-Element-Method (DEM). As for materials, recycling issues and the use of Phase-Change-Materials (PCM) or metallic ingredients for inductive thermal crack healing are addressed. In order to remind that material design must also account for the workability during the process of compaction, the new Compaction-Flow-Test (CFT) developed at KTH is shortly presented. Innovative ideas for structural material composition are also mentioned, such as “artificial aggregates” or “additive manufacturing”, being aware that there is still a long way to go. Regarding pavement systems, ideas for multifunctional road applications are proposed. Focus is also put on special issues, such as construction joints.

scholarly journals Detection Limits of DLS and UV-Vis Spectroscopy in Characterization of Polydisperse Nanoparticles Colloids

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Emilia Tomaszewska ◽  
Katarzyna Soliwoda ◽  
Kinga Kadziola ◽  
Beata Tkacz-Szczesna ◽  
Grzegorz Celichowski ◽  
...  
Keyword(s):  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Point Of View ◽  
Spectroscopy Analysis ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
The One

Dynamic light scattering is a method that depends on the interaction of light with particles. This method can be used for measurements of narrow particle size distributions especially in the range of 2–500 nm. Sample polydispersity can distort the results, and we could not see the real populations of particles because big particles presented in the sample can screen smaller ones. Although the theory and mathematical basics of DLS technique are already well known, little has been done to determine its limits experimentally. The size and size distribution of artificially prepared polydisperse silver nanoparticles (NPs) colloids were studied using dynamic light scattering (DLS) and ultraviolet-visible (UV-Vis) spectroscopy. Polydisperse colloids were prepared based on the mixture of chemically synthesized monodisperse colloids well characterized by atomic force microscopy (AFM), transmission electron microscopy (TEM), DLS, and UV-Vis spectroscopy. Analysis of the DLS results obtained for polydisperse colloids reveals that several percent of the volume content of bigger NPs could screen completely the presence of smaller ones. The presented results could be extremely important from nanoparticles metrology point of view and should help to understand experimental data especially for the one who works with DLS and/or UV-Vis only.

scholarly journals Physics Comes to the Aid of Medicine—Clinically-Relevant Microorganisms through the Eyes of Atomic Force Microscope

Pathogens ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 969
Author(s):  
Mateusz Cieśluk ◽  
Piotr Deptuła ◽  
Ewelina Piktel ◽  
Krzysztof Fiedoruk ◽  
Łukasz Suprewicz ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Antimicrobial Agents ◽  
Antimicrobial Treatment ◽  
Point Of View ◽  
Diagnostic Methods ◽  
Drug Resistant ◽  
Bacterial Strains ◽  
Force Microscopy ◽  
Atomic Force ◽  
Recent Developments

Despite the hope that was raised with the implementation of antibiotics to the treatment of infections in medical practice, the initial enthusiasm has substantially faded due to increasing drug resistance in pathogenic microorganisms. Therefore, there is a need for novel analytical and diagnostic methods in order to extend our knowledge regarding the mode of action of the conventional and novel antimicrobial agents from a perspective of single microbial cells as well as their communities growing in infected sites, i.e., biofilms. In recent years, atomic force microscopy (AFM) has been mostly used to study different aspects of the pathophysiology of noninfectious conditions with attempts to characterize morphological and rheological properties of tissues, individual mammalian cells as well as their organelles and extracellular matrix, and cells’ mechanical changes upon exposure to different stimuli. At the same time, an ever-growing number of studies have demonstrated AFM as a valuable approach in studying microorganisms in regard to changes in their morphology and nanomechanical properties, e.g., stiffness in response to antimicrobial treatment or interaction with a substrate as well as the mechanisms behind their virulence. This review summarizes recent developments and the authors’ point of view on AFM-based evaluation of microorganisms’ response to applied antimicrobial treatment within a group of selected bacteria, fungi, and viruses. The AFM potential in development of modern diagnostic and therapeutic methods for combating of infections caused by drug-resistant bacterial strains is also discussed.

Sporopollenin Nanostructure of Ilex paraguariensis A.St.Hil Pollen Grains

2005 ◽  
Vol 11 (S03) ◽  
pp. 78-81
Author(s):  
R. P. Santos ◽  
L. M. Rebelo ◽  
E. F. Costa ◽  
A. A. X. Santiago ◽  
V. N. Freire ◽  
...  
Keyword(s):  
Pollen Grains ◽  
Point Of View ◽  
Ilex Paraguariensis ◽  
Spores And Pollen ◽  
Coarse Powder ◽  
Force Microscopy ◽  
Male Gametes ◽  
Atomic Force ◽  
Ideal Method ◽  
Pollen Grain Wall

Pollens appear like a fine to coarse powder that is liberated by the microsporangia of Gimnosperms and Angiosperms. The pollen grain wall, the sporoderm, envelopes the microgametophytes (male gametophytes), which produce the male gametes of seed plants. Pollen grains are interesting from the material science point of view since the native polymer, the sporopollenin, found in the sporoderm outer layer (exine), is one of the toughest known materials which is degraded by oxidation but is resistant to reduction. This property permits the sporopollenin persistence as an unaltered polymer in sediments of great age, e.g the Ordovician period, 400 million years ago. Sporopollenin is a mixture of fatty acids, phenyl-derivatives as p-coumaric acid, and carotenes [1]. Its nanostructure is not yet completed revealed. Therefore, more studies must be performed. A number of models have been proposed for the sporopollenin nanostructure of spores and pollen grains [2]. Rowley et al. [3-4] interpret exine structure as being formed by helical subunits, based on transmission and scanning electron microscope (TEM and SEM) studies. The atomic force microscopy (AFM) is the ideal method to study the sporopollenin nanostructure [5] since the arrangement of components is not visualized easily through other microscope techniques (e.g. TEM and SEM). In the present work, we used AFM to study the sporopollenin nanostructure of the Ilex paraguariensis A.St.Hil. exine, an Angiosperm (Aquifoliaceae).

High Resolution DNA Imaging by Dynamic Atomic Force Microscopy: The Effect of the Substrate and Sample Preparation

2014 ◽  
Vol 1652 ◽  
Author(s):  
Tzu-Chieh Tang ◽  
Carlo A. Amadei ◽  
Matteo Chiesa
Keyword(s):  
Atomic Force Microscopy ◽  
Metal Ions ◽  
Physicochemical Characteristics ◽  
Temporal Variations ◽  
Point Of View ◽  
Ion Distribution ◽  
Nickel Ion ◽  
Force Microscopy ◽  
Atomic Force ◽  
Force Profile

ABSTRACTAdsorption of charged biomolecules onto atomically flat mica substrates is facilitated by the deposition of metal ions. Despite successfully acting as preferential anchoring sites, the presence of ions on the mica surface also changes its physicochemical characteristics something that is rarely quantified from a nanoscale point of view. In this study the nanoscale physicochemical properties of nickel-functionalized Muscovite mica are investigated by reconstructing the conservative force profile between an atomic force microscopy (AFM) tip and the surface. Various nickel ion concentrations (i.e. 1.0 mM to 20.0 mM) along with different incubation times (30 seconds and 5 minutes) are directly analyzed. Details in the spatial and temporal variations in surface properties due to the ion mediated adsorption of water are presented in details and in light of the binding efficiency of the metal ions. This insight benefits our understanding in the behavior of ion distribution that plays a crucial role in biomolecule imaging using AFM.

Non-Thermal Plasma Aided Soil Decontamination

2013 ◽  
Vol 16 (1) ◽  
Author(s):  
Henryka D. Stryczewska ◽  
Joanna Pawłat ◽  
Kenji Ebihara
Keyword(s):  
Point Of View ◽  
Treatment Technique ◽  
Soil Decontamination ◽  
Chemical Methods ◽  
Force Microscopy ◽  
Atomic Force ◽  
Biological Phenomena ◽  
Dna Strands ◽  
Non Thermal Plasma ◽  
Short Time

AbstractLow temperature atmospheric pressure plasmas (LTPs) together with advanced oxidation processes (AOPs) are alternative to conventional chemical methods of soil decontamination. The processing of soil itself depends on several factors, like type of soil and pollutants, treatment technique, geological and atmospheric circumstances. In the paper problems of soil, water, buildings, farms, land, and housing contaminations after floods and ecological disasters have been introduced. Plasma aided techniques together with AOPs have been presented from the point of view of decontamination potential as well as their impact on soil properties and fertility. Additionally, nanosize biological phenomena occurring in DNA strands during ozonation were visualized. The reaction of ozone with DNA is essential to understand the sterilization in agricultural soil. The structural images of the DNA samples were taken with the atomic force microscopy (AFM). It was shown that highly concentrated ozone broke hydrogen bonding of nuclei bases of DNA in relatively short time.

scholarly journals Increasing the uniformity of road surface loading to extend its service life

2020 ◽  
Vol 17 (2) ◽  
pp. 138-144
Author(s):  
R. V. Andronov ◽  
◽  
B. P. Elkin ◽  
Keyword(s):  
Service Life ◽  
Asphalt Concrete ◽  
Cost Effective ◽  
Point Of View ◽  
The Road ◽  
Optimal Value ◽  
Scientific Substantiation ◽  
Research Experiment ◽  
On The Road ◽  
Pilot Implementation

The study reveals the problem of heterogeneous loading of road surfacing with vehicle wheels, which leads to the rapid appearance of rutting on the road within 2-3 years and increases the burden on the budgets of the road sectors of cities, regions and the country. The most cost-effective way of extending the service life of road surfacing is presented, namely, periodic shifting of the rolling strips (PSRS), which has passed the stages of research, experiment and the beginning of pilot implementation, but it has not yet found a wide application. The authors review the materials of research on asphalt concrete on rutting testers, asphalt concrete surfacing on the tracks and beyond them, as a scientific substantiation for engineering innovation. The optimal value of the periodic road markup offset is determined from the point of view of probability theory. It is proposed to actively apply the PSRS method on the roads of cities and regions in different climatic zones.

scholarly journals Study of the Electrical Properties of Porous Silicon Prepared by Electrochemical Etching Technique

2019 ◽  
Vol 54 (5) ◽  
Author(s):  
Warood Kream Alaarage ◽  
Luma Hafedh Abed Oneiza ◽  
Mohanad Ghulam Murad Alzubaidi
Keyword(s):  
Electrical Properties ◽  
Porous Silicon ◽  
Ideality Factor ◽  
Thermal Emission ◽  
Electrochemical Etching ◽  
Point Of View ◽  
Etching Technique ◽  
Force Microscopy ◽  
Atomic Force ◽  
P Type

In our work, a P-type porous silicon (PSi) with orientation (100) have been prepared using the chemical etching method; the goal is to study the electrical properties of PSi samples prepared with completely different etching current (7, 9, 11 and 13) mA and glued for (15 min) anodization time. Depending on the atomic force microscopy (AFM) investigation, we notice the roughness of Si surface increases with increasing etching current because of increases within the dimension (diameter) of surface pits. The electrical and optoelectronic properties of prepared PSi, specifically capacitance-voltage (C-V), current-voltage (I-V), responsivity and detectivity, are analyzed. It had been found that electrical characteristics of porous Si samples measured in dark (Id) and below illumination (IPh) will be fitted well by the equations of thermal emission. From this point of view, Schottky barrier height (ɸB) and ideality factor (n) of made-up photodetectors were calculated. We tended to determine from I-V characteristics of a dark, and illuminations that the pass current through the PSi layer reduced by increasing the etching current, as a result of increasing the electrical resistance of PSi layer and therefore the optimum value of ideality factor is (2.7), whereas from C-V characteristic we determined that in-built potential accumulated with increasing etching current. The results show that there are clear results for better performance of photodetectors.

Laser-induced modification of amorphous GST225 phase change materials

2019 ◽  
Vol 107 (3) ◽  
pp. 307
Author(s):  
Sergey A. Kozyukhin ◽  
Petr I. Lazarenko ◽  
Yuri V. Vorobyov ◽  
Mikhail S. Savelyev ◽  
Alexander A. Polokhin ◽  
...  
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Crystallization Behavior ◽  
Phase Change Materials ◽  
Laser Pulses ◽  
Nanosecond Laser ◽  
Force Microscopy ◽  
Micro Raman Spectroscopy ◽  
Atomic Force ◽  
Nanosecond Laser Pulses

In this paper, we have studied the crystallization behavior of amorphous GST225 thin films upon irradiation with nanosecond laser pulses. Crystalline and melt-quenched amorphous regions were produced by exposure to laser single or multipulses, and were characterized by the optical microscopy and by the micro-Raman spectroscopy. Transition region between the amorphous and crystalline parts of the laser-modified area was investigated by atomic force microscopy. Using irradiation by single laser pulses with varying fluence, it was verified that crystallization was possible if the fluence is more than 90.4 mJ/cm2.

scholarly journals Local force titration of wood surfaces by chemical force microscopy

Cellulose ◽  
2021 ◽  
Author(s):  
Claudia Gusenbauer ◽  
Karolina Peter ◽  
Etienne Cabane ◽  
Johannes Konnerth
Keyword(s):  
Treated Wood ◽  
Material Design ◽  
Natural State ◽  
Adhesion Forces ◽  
Chemical Surface ◽  
Force Microscopy ◽  
Atomic Force ◽  
Functionalized Tips ◽  
Wood Surfaces ◽  
Chemical Force

AbstractChemical force microcopy, a variation of atomic force microscopy, opened the door to visualize chemical nano-properties of various materials in their natural state. The key function of this method is given by translating adhesion forces between a functionalized tip and the sample to chemical surface behavior. In force titration, these adhesion forces are studied in different pH buffers, which allows estimating the pKa value of the analyzed surface. Herein, we report the use of this method to study natural and chemically treated wood surfaces, which are of interest in sustainable material design. First, we show varying adhesion phenomena of OH- and COOH-functionalized tips on native spruce wood cells. Then, we demonstrate how peak force tapping with chemically functionalized tips can be used to estimate the pKa value of gold substrates (pKa ≈ 5.2) and different wood cell wall layers with high spatial resolution. Additionally, the swelling behavior of wood samples is analyzed in varying pH buffers. With the applied method, chemical surface properties of complex natural substrates can be analyzed. Graphical abstract

Sign in / Sign up

Export Citation Format

Share Document