Samples Of Various Materials Research Articles

Material preferences in kea (Nestor notabilis)

New Zealand’s kea parrot (Nestor notabilis) is a highly neophilic species that is attracted to human settlements and structures. These environments pose several risks to this endangered species, but also pose a management challenge in how to best ensure that a neophilic species is kept away from the allure of ever-changing human environments. One possible mitigation strategy is the implementation of “kea jungle gyms” to provide kea with a potentially safer alternative to novelty, but little is known about how to design these structures to their fullest potential. In this study, we presented kea with samples of various materials to determine both what materials and their properties kea prefer to interact with, and which materials kea are least likely to engage with. We found that kea spent longer interacting with wood and some polymer plastics, and the least time interacting with hard metals, such as steel and stainless steel. These findings are discussed in the context of generating safe and effective management strategies that can be implemented for wild kea populations in the future, particularly with regard to appropriate designs of jungle gyms to encourage kea away from human settlements.

IMPACT OF SPACECRAFT AND ISS ENGINES ON EXPERIMENTAL SAMPLES OF VARIOUS MATERIALS MOUNTED ON THE OUTER SURFACE OF THE "ZVEZDA" MODULE

The work presents a study of the influence of the spacecraft and ISS engines during the correction of the station's orbit. The zones of action of the gas jets and their impact on the environment and the surfaces of the experimental samples of various materials mounted on the outside of the Zvezda module were determined.

Technology of experiments on non-thermal effects of powerful lectromagnetic pulses on natural and artificial environments

The features of the technology of experiments on the non-thermal effects of high-power nanosecond pulses are considered using the example of a setup used to modify biological media and other objects with heterogeneous electrophysical characteristics. An experimental setup has been created to study the non-thermal effects of high-power pulses on samples of various materials, which generates pulses with a repetition frequency of up to 500 Hz, amplitude up to 60 kV and duration 5 ns. Simulation of transient processes in the equivalent electrical circuit of the load was carried out, and a biological one was used as a load material placed in a microplate.

Температурна характеристика електричного опору тензометра при вимірюванні статичних та термічних напружень деталей при температурі до 700 °С

An overview of the existing methods of measuring static stresses at elevated temperatures, at which it is problematic to use classical strain gauges, and methods of compensating the imaginary temperature deformation was performed. Namely: the use of multi-component alloys, the manufacture of active and compensatory sensitive elements from different alloys, which should theoretically compensate for each other's shortcomings. In practice, this can be sufficiently achieved only in a narrow temperature range. The described primary transducer is a rectangular strain-gauge rosette for measuring static and thermal stresses in structural parts operating under extreme conditions at temperatures up to 700°C. This sensor is a two-layer rosette consisting of two sensitive elements (SE), the main axes of which are rotated relative to each other by 90°. The lower SE perceives the main deformation of the part, and the upper one, located above the lower one, plays the role of a temperature-compensating electrical resistance of the element and simultaneously registers the transverse deformation of the part. SE rosettes were made of a wire with a diameter of 30 microns of the Х20Н80 alloy and fixed to each other and to the part using Ц-165-32А cement. The experimental study consisted in determining the temperature characteristics of the resistance of both the lower and the upper SE of the studied strain gauge associated with the temperature expansion of the part-strain gauge system as well as with the shunting of the insulator-connector and the change in the specific resistance of the SE material. Experimental determination of apparent strain gauge deformation at different temperatures was performed. To determine the influence of the coefficient of linear expansion of the material of the part on the change in the resistance of the SE, strain gauges were attached to samples of various materials. The change in the apparent deformation of the strain gauge in the temperature range from room temperature to 700 °C is shown. Its maximum value for the ceramic sample was less than 350 µm/m, for the 30ХГСА steel sample it was less than 1000 µm/m, and for the ВЖЛ14Н-ВІ alloy sample it was less than 750 µm/m. Dependencies were obtained that allow corrections to be made in the result of a real study of the stressed state of the part to achieve the maximum accuracy of measurements.

Experimental study on the load-area relation of rough surfaces and comparison with theoretical model

It is of critical significance to accurately measure or predict the real contact areas between rough solids in engineering. In this study, based on the frustrated total internal reflection technique and an Otsu method, an optical apparatus is designed to capture the real contact areas between rough metallic samples and flat quartz glass. Moreover, an incremental equivalent contact model developed recently by our group is adopted to predict the load-area relationship. For samples of various materials and morphologies, it is found that the proposed contact model agrees well with the experimentally measured results, which verifies the efficiency of the incremental equivalent contact model.

Charge-Sensitive Technique for Deformation Processes’ Study

Surface charge can be used as an information parameter about the change in the state of the material under the action of mechanical stresses. The aim of the work was to develop methods for studying deformation processes in metallic and polymeric materials using a charge-sensitive method.Experimental studies of deformation processes under tensile, compressive and impact loads were carried out on samples of various materials: aluminum alloy of AMg2 grade, steel of grade 08PS, high-pressure polyethylene of grade 12203-250 and samples of composite materials based on it, F4 polytetrafluoroethylene. As a research method, the analysis of changes in the relative values of the surface electron work function in the case of metals and the surface electrostatic potential in the case of polymers and composite materials is used. A scanning modification of a charge-sensitive probe is used as a measuring instrument.The results of experimental studies of materials in a stress-strain state demonstrate the high efficiency of the proposed method. The research methodology makes it possible to detect local changes in the surface potential of the material in the area of deformations, which are not detected on a macroscopic scale using standard methods. The results obtained can serve as a basis for the development of new methods and techniques for studying the mechanical properties of both metals and dielectric materials.

Evaluation of Apoptotic Effect of Betanin Nanoparticles Against Squamous Cell Carcinoma Cell Line Compared to Doxorubicin

Aim: to evaluate the anticancer effect of nano sized betanine particles (betanine NP) on squamous cell carcinoma cell line compared to doxorubicin (DOX) by measuring apoptosis through caspase 3. Material and Methods: Three groups of the human tongue squamous cell carcinoma cell line (SCC 25) were created, and two of them were treated with DOX and betanine NP. The third group served as a negative control and was not given any treatment. To evaluate the concentration of caspase 3 using the ElISA technology, different quantities of betanin NP and DOX were administered to SCC25 at 48- and 72-hour intervals. Results: Caspase 3 levels in the current investigation were 501.69.93, 543.86.71 pg/ml for DOX and 336.913.1, 405.53.5, and respectively for betanine NP in 48h and 72h intervals. Additionally, morphological analysis was performed to demonstrate the cells’ apoptotic alterations. There was a highly statistically significant difference between samples of various materials, as revealed by the ANOVA test for Comparison between groups using the ELISA technique for caspase 3 detection at 48h and 72h (p0.001). These findings suggest that DOX has a stronger apoptotic effect on SCC25 cells than betanin NP. Conclusion: Our findings explained that DOX and betanine NP can induce cancer cell death against SCC 25 cell lines by increasing the concentration of caspase 3. DOX has higher apoptotic effect on SCC25 cells than betanin NP according to ELISA technique.

Prevention of complications after the surgical treatment of the facial fractures

In modern society, with a high rate of industrialization and, at the same time, a decrease in the standard of living, an increase in maxillofacial injury (MFI) has been noted, ranging from 6 to 16% of the total number of injuries. In addition, MFI is a public health problem due to its high prevalence and the need for resources to treat it, as well as the financial and social impact of MFI victims on the health care system. Osteosynthesis of the bones of the facial skeleton with titanium miniplates and screws is an effective way to treat fractures of the bones of the facial skull. According to the studied literature sources, researchers continue to search for the most inert materials for surgical otheosynthesis. Samples of various materials are examined for the adhesive ability of the main pathogens of purulent-inflammatory diseases, inertness, toxicity and other indicators. But studies are few and there is no conclusive evidence in favor of either material. However, the use of titanium miniplates and screws coated with silicon carbide is advisable for the prevention of postoperative complications. The use of titanium miniplates and screws coated with silicon carbide is the method of choice in the treatment of infected fractures of the bones of the facial skeleton.

Ultimate pressure determination in hydraulic fracturing of boreholes for different rock failure criteria

The problem on elastoplastic deformation and rock failure around boreholes under the action of internal pressure is considered. The stress state in the intact rock mass is assumed to be hydrostatic. The hydraulic fracturing pressure is conventionally determined by the maximum normal stress criterion. However, the experimental studies described in scientific articles show that this criterion is not consistent with the results obtained in the course of laboratory tests on failure of cylindrical and spherical cavities made in rock samples. It has been known that test results on complex loading for solid samples of various materials are not confirmed by the theory of maximum normal stress both in terms of ultimate load value and direction of failure surface propagation. In this case, for the complex stress state of rocks, it is proposed to determine the ultimate pressure by the experimentally substantiated fracture criteria which are in good agreement with the results of laboratory tests on hydraulic fracturing of boreholes.

Multiple zero-group velocity resonances in elastic layered structures

To date, the phenomenon of zero group velocity (ZGV) Lamb wave in a stress-free elastic plate has been well studied and used in non-destructive material characterization, electroacoustic devices and some other applications. This phenomenon is associated with the backward mode appearing in the range limited by the ZGV and cutoff frequencies. The modal frequency response of the structure, primarily the spectrum of the corresponding guided wave (GW) excited in the plate by a force source, is featured by a sharp peak at the ZGV frequency, allowing its experimental detection. Other peaks appearing at the cutoff frequencies indicate thickness resonances. In a layered half-space of infinite thickness, the backward-mode bend of the dispersion curve turns into a double bend that gives rise to three GWs associated with the same branch (one backward and two forward modes). Moreover, several adjacent branches with double bends, and, thus, several peaks, can appear in a narrow range as the number of layers increases, indicating multiple ZGV resonances. Such dispersion curves with double ZGV points were also found in waveguides of finite thickness with anisotropic or contrast material properties; however, their resonance manifestation is poorly studied. In this article, we consider and discuss several kinds of multi-peak ZGV responses using examples of layered samples of various materials. Along with the expected increase in the number of peaks in multilayer structures with contrast layers, it was noted that some ZGV points may or may not appear in peaks, depending on the type of load.

Static method of rock destruction with using a non-explosive destructive mixture

The authors developed a mathematical model of the location of boreholes when using a non-explosive destructive mixture (NDM), which contributes to the formation of a continuous line of cracks and the smooth separation of rocks in the massif. The dependences of the change in the effective distance between contour holes on their diameter, compressive stress at the hole wall, Poisson's ratio, the tensile strength of the rock, and the additional stress directed at moving the block walls and opening them when using the NDM are established. A series of experiments on finding an optimum compounding of structure of NDM which would allow to accelerate process of hydration without additional heat release and to provide high pressure during 5-8 h after use of structure was carried out. Variants of the chemical mixture that maximizes the expansion and destruction of rocks were optimized. More than 200 experiments on rupture of samples of various materials (glass bubbles, plaster, brick, marble) were conducted. On the basis of the received results, a method was developed for formulating composition of NDM with using components from local raw materials, which is safe for storage, transportation and use, creates high internal pressure in the holes and contributes to static destruction and rupture of rocks. The method for separating monoliths from the massif with use of new composition of the NDM is also developed. Implementation of the proposed method allows to displace a block of monolith into the goaf of the pit under the influence of high pressure of self-expansion with no spontaneous outburst of mixture. Experimental-industrial tests of the proposed composition and method of the NDM production were carried out in the Nuratinsky marble deposit of the Navoi region. As compared with the drilling and blasting method, method of separation of monoliths from massif by using the new composition of NDM makes it possible to reduce labour intensity of performed works, provides protection of environment, reduces cost of production and energy intensity of mining works, as well as increases safety of their execution Keywords: mathematical model of the location of holes, non-explosive destructive mixture, formation of continuous line of cracks, high internal pressure in the holes.

MDM: A flight mission to observe materials degradation in-situ on satellite in super low Earth orbit

Satellites in low Earth orbit (LEO) are subject to several environmental factors, atomic oxygen (AO) having the greatest effect on space materials, especially polymers. Recently, the possibility of utilizing orbits at an altitude lower than 300 km (super LEO or S-LEO) has been explored, but one complication in using these orbits is that AO fluence is expected to far exceed that in an ordinary LEO. The effect of S-LEO AO on materials used in space is not well understood. To investigate the influence of S-LEO AO on space materials, we developed the Material Degradation Monitor (MDM), which is installed on a JAXA spacecraft, the Super Low Altitude Test Satellite (SLATS, also known as TSUBAME). The SLATS is the first S-LEO satellite to operate at an altitude under 200 km and the MDM is the first near real-time experiment to examine the effects of AO on materials in this orbit. The aim of the MDM is to clarify degradation behaviors of the space materials according to AO fluence. We developed the instruments needed to detect AO fluence and the changes it causes to samples of various materials in S-LEO. The MDM performed as expected until the end of the SLATS operation. Some changes in materials were found from the images taken from front and back LEDs. Although there was no breakage by AO, optical properties changed that are assumed to be due to material erosion by AO.

ЗАКОН РАСПРЕДЕЛЕНИЯ РАЗРУШАЮЩИХ НАГРУЗОК ЭЛЕМЕНТОВ КАРКАСА КУПОЛА ПАРАШЮТА

It is known that during operation or long-term storage, there is a significant deterioration (degradation) of the strength characteristics of the strength elements of the parachute canopy’s carcase, including shroud lines, canopy’s fabric, reinforcement tapes, free ends of the suspension system, leg straps, etc.Parachutes are designed considering the specific safety factors of power elements for the extreme loads resistance at the moment of parachute opening. Further operation after the specified period with unchanged safety factors is possible only in flight conditions limitation, in particular, landing speeds. Strength characteristics are characterized by significant scattering. The design of parachutes is carried out considering the guaranteed values of destructive loads of elements with a given level of reliability. In this case, the law of destructive loads distribution must be known.It was tested the normal distribution applicability of the strength characteristics applying the compound compliance criterion. The basis is the data of strength tests until the destruction of shroud lines samples and fabric of the canopy warpwise and wefting. The samples were cut from D-5 series 2 parachute of the year 1983, Z-5 reserve parachute of 1984, the rescue parachute C-5 K series 2 of the 1989. It was tested totally 301 samples of various materials from these parachutes. At the first stage of processing the test data, by experimental determination of the breaking load, the gross emissions were rejected, then a composite criterion for compliance with the normal law was applied.According to the results of comparison with experimental data, the validity of the normal distribution of destructive loads for the shroud lines and canopy’s fabrics both warpwise and wefting is unambiguously shown. The obtained result makes it possible to evaluate the strength characteristics of the carcase elements after operation or long-term storage with the required level of reliability and, in the future, to find the strength degradation factors of the power elements. These factors will limit the maximum allowed landing speed with a specific parachute.

Risk of exposure of a selected rural population in South Poland to allergenic mites. Part\xa0II: acarofauna of farm buildings

Exposure to mite allergens, especially from storage and dust mites, has been recognized as a risk factor for sensitization and allergy symptoms that could develop into asthma. The aim of this study was to investigate the occurrence of mites in debris and litter from selected farm buildings of the Małopolskie province, South Poland, with particular reference to allergenic and/or parasitic species as a potential risk factor of diseases among farmers. Sixty samples of various materials (organic dust, litter, debris and residues) from farm buildings (cowsheds, barns, chaff-cutter buildings, pigsties and poultry houses) were subjected to acarological examination. The samples were collected in Lachowice and Kurów (Suski district, Małopolskie). A total of 16,719 mites were isolated including specimens from the cohort Astigmatina (27 species) which comprised species considered as allergenic (e.g., Acarus siro complex, Tyrophagus putrescentiae, Lepidoglyphus destructor, Glycyphagus domesticus, Chortoglyphus arcuatus and Gymnoglyphus longior). Species of the families Acaridae (A. siro, A. farris and A. immobilis), Glycyphagidae (G. domesticus, L. destructor and L. michaeli) and Chortoglyphidae (C. arcuatus) have been found as numerically dominant among astigmatid mites. The majority of mites were found in cowsheds (approx. 32%) and in pigsties (25.9%). The remaining mites were found in barns (19.6%), chaff-cutter buildings (13.9%) and poultry houses (8.8%). The results suggest that the allergenic mites may constitute an occupational hazard for agricultural workers in all farming environments examined.

Flame spread: Effects of microgravity and scale

For the first time, a large-scale flame spread experiment was conducted inside an orbiting spacecraft to study the effects of microgravity and scale and to address the uncertainty regarding how flames spread when there is no gravity and if the sample size and the experimental duration are, respectively, large enough and long enough to allow for unrestricted growth. Differences between flame spread in purely buoyant and purely forced flows are presented. Prior to these experiments, only samples of small size in small confined volumes had been tested in space. Therefore the first and third flights in the experimental series, called “Saffire,” studied large-scale flame spread over a 94 cm long by 40.6 cm wide cotton-fiberglass fabric. The second flight examined an array of nine smaller samples of various materials each measuring 29 cm long by 5 cm wide. Among them were two of the same cotton-fiberglass fabric used in the large-scale tests and a thick, flat PMMA sample (1-cm thick). The forced airflow was 20–25 cm/s, which is typical of air circulation speeds in a spacecraft. The experiments took place aboard the Cygnus vehicle, a large unmanned resupply spacecraft to the International Space Station (ISS). The experiments were carried out in orbit before the Cygnus vehicle, reloaded with ISS trash, re-entered the Earth's atmosphere and perished. The downloaded test data show that a concurrent (downstream) spreading flame over thin fabrics in microgravity reaches a steady spread rate and a limiting length. The flame over the thick PMMA sample approaches a non-growing, steady state in the 15 min burning duration and has a limiting pyrolysis length. In contrast, upward (concurrent) flame spread at normal gravity on Earth is usually found to be accelerating so that the flame size grows with time. The existence of a flame size limit has important considerations for spacecraft fire safety as it can be used to establish the heat release rate in the vehicle. The findings and the scientific explanations of this series of innovative, novel and unique experiments are presented, analyzed and discussed.

Gas-Dynamic Research Technique of Indirectly Irradiated Targets in Porous Materials at Iskra-5 Fasility

In this paper, studies of gas-dynamic flows in samples of various materials loaded with an X-ray flux in “Illuminator”-type targets on Iskra-5 laser facility of the ILFI VNIIEF are presented. The obtained results on the velocity of shock waves in the sample under the study are compared with model calculations to match the gas-dynamic parameters to their calculated estimates.

Formation and growth of nanostructures on the surface of solids melted by laser pulses

The possibility of forming nanostructures on the surface of solids by the action of nanosecond laser pulses causing the material to melt has been shown both theoretically and experimentally. The dependence that the characteristic sizes of the surface nanostructures have on the energy of the laser beam and duration is established. Experimental results on samples of various materials obtained by direct laser nano-structuring using an ArF laser and images of titanium samples with surface nanostructures are presented.

Development of a chemiluminescent ELISA and a colloidal gold-based LFIA for TNT detection

To identify the explosive used in a terrorist attack, or to obtain an early sign of environmental pollution it is important to use simple and rapid assays able to detect analytes at low levels, possibly on-site. This is particularly true for TNT (2,4,6-trinitrotoluene), one of the most employed explosives in the 20th century and at the same time, because of its toxicity, a well known pollutant. In this work we describe the development of an indirect competitive ELISA with chemiluminescent detection (CL-ELISA) and of a lateral-flow immunoassay (LFIA) based on colloidal gold nanoparticle labels. A commercially available monoclonal antibody was used and 13 specially synthesized conjugates were tested. We optimized the assay by determining the optimal concentration of monoclonal antibody and conjugates and the influence of various non-specific factors such as: tolerance to organic solvents at different concentrations, the washing and competitive step time, and the cross-reactivity with related compounds. The sensitivity and reproducibility of the CL-ELISA were good (LOD and IC(50) values in the ng mL(-1) range, and CV value about 7%). It has been applied to real samples of various materials involved in a controlled explosion of an "improvised explosive device". Three extraction procedures were tested on these samples, all employing methanol as the solvent. The lateral flow immunoassay (LFIA), developed by using the same immunoreagents, reached a detection limit of 1 microg mL(-1) when tested on the same samples analysed by CL-ELISA.

Angular distribution of proton leakage from a fusion plasma using ultra low-level γ-ray spectrometry

This experiment aimed at studying a technique to measure the leakage of charged particles from a fusion plasma. The activity induced in samples of various materials placed on a special holder inside a Tokamak was measured using ultra low-level gamma-ray spectrometry (ULGS) performed in three underground laboratories. In total, 27 radionuclides were detected in this experiment. Seven of these radionuclides were mainly produced by proton interactions. For two of them it was possible to determine their angular distribution.

Material Orientation Artifact Studies in Magnetic Resonance Imaging

With the increased interest of MRI guided interventional procedures in modern medical treatments, image distortion and artifact formation based on material selection and orientation within the MRI scanner are central concerns for precise object localization. The goal of this study was to illustrate the artifact behavior of materials with various magnetic susceptibilities and radio frequency conductivity values corresponding to object orientation relative to the primary magnetic field. To test the effects of orientation on image distortion and image artifacts, 0.125 inch cylindrical test samples of various materials were imaged using a clinical Siemens 3 Tesla MR scanner. Modern medical instrumentation and surgical utensils are typically made from highly paramagnetic materials (e.g., titanium, nitinol, or stainless steel) which also have high RF conductivities. The combination of these two material properties cause both primary magnetic field (B0) and RF field (B1) inhomogeneities which lead to local image distortions. A change in the local magnetic field induces errors within the slice selection gradient, as the precessional frequency of the proton nuclei in the desired region of interest will not correspond to the exact spatial location on the object and will excite a broader region due to the RF conductivity of the material. Conversely to more traditional surgical materials, diamagnetic materials (e.g., bismuth, pyrolytic carbon, water, most plastics) are free from the susceptibility artifacts due to B0 inhomogeneities and thus offer a level of MR compatibility that traditional materials cannot. A specific testing phantom was built to fit a clinical wrist coil. The phantom consisted of an aqueous solution of gadolinium and copper sulfate to increase image contrast and a rotatable turret post for sample positioning. The particular materials studied were chosen to demonstrate the wide variation in both magnetic susceptibility values and RF conductivities (e.g., 6A1-4V titanium, 316L stainless steel, carbon fiber, 6061 T6 aluminum, brass, copper, beryllium copper). ImageJ software measured the overall pixel area and major dimension of each MR image artifact at 0, 45, and 90 degree orientations of each test sample relative to B0. The results of the measurements indicated measurable increases in signal are of the paramagnetic and highly conductive test specimens orientated orthogonal to the primary magnetic field. For instance, two common medical grade materials such as 316L stainless steel and 6Al-4V titanium resulted in artifact area increases of 770±10% and 234±10%, respectively, relative to the actual cross sectional area of the sample. Conversely, the more diamagnetic materials, carbon fiber and beryllium copper demonstrated increased artifact areas of 8±10% and 12±10%, respectively. Errors in artifact area percentage growth measurement are primarily attributed to manual image segmentation and variation in coil positioning within the MRI bore. The results indicate that MR image artifact size and object distortion characteristics can be influenced by both material selection and object orientation relative to the primary magnetic field. In the interest of accurate navigation of image guided equipment and devices, interventional devices should be tested for image distortion in multiple orientations. This work is supported by MIMTeC, a National Science Foundation Industry University Collaborative Research Center and by NIH Grant P30 NS057091.