Metallic Body Research Articles

Preparation and application of copper nanoclusters as a fluorescent sensor for sensitive detection of tartrazine

As an important way to detect tartrazine, a probe with excellent fluorescence properties is of great significance in fluorescence detection method. Copper nanoclusters (Cu NCs) was prepared by chemical reduction method, in which copper sulfate as metal body, folic acid as capping reagent and ascorbic acid as reducing agent. In the light of inner filter effect and static quenching mechanism, a fluorescence sensor for tartrazine measurement was designed based on Cu NCs with excellent selectivity. The spherical Cu NCs with uniform size emitted blue fluorescence at 443 nm when the excitation wavelength was located at 353 nm. Under the optimum detecting condition, the corresponding linear range and LOD were 0.5–50 μM and 0.071 μM, respectively. Coupled with pleasing recovery experiments in real samples, this as-proposed platform was very promising for tartrazine detection.

3D Printing of Metals with sub-10µm Resolution.

The ability to manufacture 3D metallic architectures with microscale resolution is greatly pursued because of their diverse applications in microelectromechanical systems (MEMS) including microelectronics, mechanical metamaterials, and biomedical devices. However, the well-developed photolithography and emerging metal additive manufacturing technologies have limited abilities in manufacturing micro-scaled metallic structures with freeform 3D geometries. Here, for the first time, the high-fidelity fabrication of arbitrary metallic motifs with sub-10µm resolution is achieved by employing an embedded-writing embedded-sintering (EWES) process. A paraffin wax-based supporting matrix with high thermal stability is developed, which permits the printed silver nanoparticle ink to be pre-sintered at 175°C to form metallic green bodies. Via carefully regulating the matrix components, the printing resolution is tuned down to ≈7µm. The green bodies are then embedded in a supporting salt bath and further sintered to realize freeform 3D silver motifs with great structure fidelity. 3D printing of various micro-scaled silver architectures is demonstrated such as micro-spring arrays, BCC lattices, horn antenna, and rotatable windmills. This method can be extended to the high-fidelity 3D printing of other metals and metal oxides which require high-temperature sintering, providing the pathways toward the design and fabrication of 3D MEMS with complex geometries and functions.

Groundwater flow paths using combined self-potential, electrical resistivity, and induced polarization signals

SUMMARY The dam of Lampy (Black Mountain, Aude, France) is considered as one of the oldest dams in France. A geophysical survey is performed to better understand the pattern of groundwater flow downstream of this dam in the granitic substratum. Induced polarization is first used to image both electrical conductivity and normalized chargeability. Eight core samples of granite from this site are measured and analysed in the laboratory. Their electrical conductivity and normalized chargeability are expressed as a function of the porosity and cation exchange capacity (CEC). The field data and the petrophysical results are used to image the water content, the CEC and the permeability distribution of the substratum. Then, self-potential is used as a complementary passive geophysical technique, which, in absence of metallic bodies, is directly sensitive to groundwater flow through the so-called streaming potential effect. Indeed, the excess of electrical charges in the vicinity of the solid grains, in the so-called double layer, is dragged by the ground water flow generating in turn an electrical (streaming) current and therefore an electrical field. A map of the resulting self-potential signals is done over the area covered by the induced polarization profiles. This map shows a large positive anomaly with an amplitude of ∼80 mV possibly associated with upwelling groundwater in an area where the soil is water-saturated. A groundwater flow simulation is performed to model this anomaly. This is done in two steps. A preliminary groundwater flow model is built using the permeability and water content distributions obtained from the induced polarization data. Then, this groundwater flow model is updated using the information contained in the self-potential data including the electrical conductivity distribution obtained through resistivity tomography. The algorithm for the inversion of the self-potential data is validated through a 2-D numerical test. This analysis yields a groundwater flow model with the flow being focused through a high permeability zone. This study shows how three geoelectrical methods (self-potential, induced polarization and electrical resistivity) can be efficiently combined to image groundwater flow in the vicinity of a dam.

Trial to Assess Chelation Therapy 2 (TACT2) and metal body burden

Trial to Assess Chelation Therapy 2 (TACT2) and metal body burden

Leidenfrost spheres, projectiles, and model boats: Assessing the drag reduction by superhydrophobic surfaces

Superhydrophobic surfaces are expected to reduce drag on bluff bodies moving in water due to the introduction of a thin air layer around the solid and the resulting partial slip boundary condition. The use of Leidenfrost vapor layers, sustained on the surface of a heated metal body is a reliable method to estimate the maximum drag reduction possible due to such air layers. In the past such an approach was used to estimate the drag reduction on a free-falling heated sphere, in which case the form drag is the lead component of the drag force. Here, we extend this approach to evaluate the effect of the thin gas layers on the hydrodynamic drag of free-falling streamlined projectiles and towed model boats, where the form drag is minimal, and the skin friction drag is the lead component of the drag force. By comparing the drag for streamlined bodies with and without sustained air-layers, we see only incremental drag reductions, for the sub-critical Reynolds number tested herein. The same is true for towed model boats. These results hold both for superhydrophobic surface treatments and Leidenfrost vapor layers. Thus, we concluded that for the investigated range of sub-critical Reynolds numbers, the skin friction drag is less sensitive to the effect of the thin gas layers compared to the form drag. These novel findings have important implications for the practical potential of energy savings using gas layers sustained on superhydrophobic surfaces.

Research and Investigation of High Frequency Profile of Step and Touch Voltages Due to Fragmentation of the Grounding Grid

The increasing demand and the benefits of electricity energy have led to the creation of huge power plants, so high voltage substations are necessary for electrical energy. Installing different small power plants to prevent consumption in different parts of a country requires reservation units and high costs for repairs, maintenance and fueling. The necessity of these substations can be searched in the lack of uniformity of different costs, the costs of generating electrical energy, the lack of consumption centers near power plants, and generally the existence of a national grid and the possibility of timely disconnection of the faulty parts of the power grid. The priority in the rehabilitating of a strong substation is to meet the system's operation needs. In all electrical installations, especially in industrial complexes, land connectivity is one of the most important and fundamental measures to protect individuals and equipment and improve the performance of the system. The purpose of ground equipment system is to potentialize the metal body of all electrical equipment with the ground to prevent electrocution and protect personnel. This type of connection is not normally a current carrier, but if one of the phases of the device is connected to the fuselage, the fault current enters the ground through this connection and closes its path through the trans neutral or the generator connected to the ground. Earth networks due to different structures of the earth in different regions may cause problems over time, one of them is the fragmentation of the earth's network due to rot of conductors or due to overvoltage. In this research at different and high frequencies, we use 3 frequencies of 50, 100 kilos and 1 MHz, to check the ground network factors and the security of equipment and people in high voltage substations, we use CDEGS software which is a specialized program for designing and investigating the earth network. Objetivo: Research and investigation of high frequency, profile of step and touch voltajes of grounding grid. Metodología: Design and modeling with Comsol software. Resultados: As the frequency increases, both the step voltage and the touch voltage at the corner points increase more. Conclusiones: By comparing the voltage profiles based on the simulation results, it was found that by increasing the frequency of the contact voltage in each profile and mesh, it is noticeably increased. The point to consider after reviewing the simulation results is that by increasing the frequency of both step voltage and touch voltage in the corner points, they are more increased than other parts.

The association between metal exposure and body mass index of preschool children of Shaanxi, China

There are few studies on the association between polymetallic exposure and obesity in preschool children, and the conclusions are inconsistent. The study aimed to explore the association between urine metals and body mass index (BMI). For 342 preschool children in the industrial park of Shaanxi, China, uniformly trained investigators collected basic information of preschoolers and measured height and weight. Morning urine were collected, and BMI were calculated. We measured concentrations of 22 urine metals by quadrupole inductively coupled plasma-mass spectrometry (ICP-MS).The least absolute shrinkage and selective operator (LASSO) regression model was used to screen urine metals larger impact on BMI. In the polymetallic exposure model, generalized linear regression was used to explore the relationship between the selected urine metals and BMI. The overall relationship between urine metals and BMI was analyzed using restricted cubic spline (RCS). The interaction method was used to explore the influence of metal-metal interaction on BMI. After adjustment for covariates, ln-transformed urinary copper (Cu) levels and urinary molybdenum (Mo) levels were negatively associated with BMI, (Cu, β=−1.219, 95% CI: −2.047, −0.391, P<0.05; Mo, β=−0.797, 95% CI: −1.508, −0.087, P<0.05). Polymetallic model showed similar results. Both ln-transformed urinary Cu levels and urinary Mo levels were negatively correlated with BMI (Cu: β=−1.556, 95% CI: −2.488, −0.624, P<0.05; Mo: β=−0.915, 95% CI: −1.817, −0.013, P<0.05). The results of RCS visually demonstrate that Cu and BMI are non-linearly correlated (Ptotal < 0.001, Pnonliearity = 0.005), Mo and BMI are linearly correlated (Ptotal < 0.05, Pnonliearity = 0.099) Urinary Cu was negatively correlated with BMI nonlinearly in preschool children, and there was a borderline interaction between urinary Mo and Cu levels.Further researches are needed to validate these associations and reveal underlying mechanisms

Fabricating a Structured Single‐Atom Catalyst via High‐Resolution Photopolymerization 3D Printing

AbstractThis study introduces a novel solution to the design of structured catalysts, integrating single‐piece 3D printing with single‐atom catalysis. Structured catalysts are widely employed in industrial processes, as they provide optimal mass and heat transfer, leading to a more efficient use of catalytic materials. They are conventionally prepared using ceramic or metallic bodies, which are then washcoated and impregnated with catalytically active layers. However, this approach may lead to adhesion issues of the latter. By employing photopolymerization printing, a stable and active single‐atom catalyst is directly shaped into a stand‐alone, single‐piece structured material. The battery of characterization methods employed in the present study confirms the uniform distribution of catalytically active species and the structural integrity of the material. Computational fluid dynamics simulations are applied to demonstrate enhanced momentum transfer and light distribution within the structured body. The materials are finally evaluated in the continuous‐flow photocatalytic oxidation of benzyl alcohol to benzaldehyde, a relevant reaction to prepare biomass‐derived building blocks. The innovative approach reported herein to manufacture a structured single‐atom catalyst circumvents the complexities of traditional synthetic methods, offering scalability and efficiency improvements, and highlights the transformative role of 3D printing in catalysis engineering to revolutionize catalysts’ design.

Method of characteristic modes

In recent years, the number of works on the method of characteristic modes and problems solved with its help has increased significantly, which indicates an awareness of its potential and, in connection with this, a growing interest in this approach. The attractiveness of this method lies in the fact that it provides a clear physical picture of the occurring phenomena and the ensuing opportunity to build on this basis methods for creating structures with the required parameters and combating undesirable phenomena. Unfortunately, in the Russian-speaking segment of applied electrodynamics, very few researchers are engaged in the development and application of the approach under consideration. The purpose of this work is to increase the interest of Russian-speaking researchers in the method of characteristic modes. A review of publications devoted to the method of characteristic modes, both early, fundamental and already classic, associated with the names of R.J. Garbacz and R.F. Harrington, and those which have appeared in recent years and offer generalizations of the method for various electrodynamic structures, has been carried out. This includes composite structures consisting of a set of metal and dielectric bodies of various configurations. In addition, variants of the method for antenna arrays of both infinite periodic and finite sizes have been considered. Issues related to modal tracking problems, orthogonal properties of characteristic modes and improving the convergence of solutions have been considered. Much attention is paid to works containing solutions to specific practical electrodynamic problems using the method of characteristic modes. The works have been shown, in which simple and effective approaches based on the method of characteristic modes are given for the design of a ship's HF antenna system, on-board aircraft antennas in the short-wave region, antennas placed on the platform of a battle tank, and the concept of designing an antenna for an electrically small-unmanned aerial vehicle has been presented. Options for solving the problem of reducing the mutual coupling of elements in antenna arrays have been shown. Attention is paid to MIMO antennas, antennas for smartphones, systems with specified radiation zeros, antennas using metasurfaces. According to the authors, the characteristic mode method, taking into account the increasing possibilities of its application, will make it possible to take the next step in the development, analysis or synthesis of new antenna structures that meet ever-increasing modern requirements.

Improved Cook Stoves to Meet Sustainable Development Goal in Ethiopia

The 2030 sustainable development goal (SDG7) target progress indicators show that developing countries are off track. Ethiopia’s low performance to the SDG7 has endangered its economic, societal, and environmental sustainability. The performance in clean cooking has contested its policy, institutional setup, and R&amp;D. The objective of this paper lies in evaluating four improved cook stoves against a traditional stove based on fuel consumption, cooking time, and emission. The study would contribute to solving the clean-cooking challenges by giving scientific evidence on the technological status of these stoves. The evaluation results show that the TCS consumed 2.7 kg of fuel, had a cooking time of 1:30 h, and used 4.3 kg CO2 per cooking period. Similarly, the ICSs required: 1.2 kg, 2 h, and 1.9 kg (EZY); 1.5 kg, 3 h, and 2.4 kg (Tikikkle); and 1.4 kg, 5 h, and 3.2 kg (Lakech), respectively. In addition, these stoves registered a thermal efficiency of 25, 17, and 19%, respectively. The metal body, insulation, and air inlet caused EZY to perform better. However, these technologies are low-order technologies, and their performance is found to be a major locking factor in ICS adoption. This evidence would help ICS actors to understand where to intervene for better adoption. Furthermore, the authors gave implementation fix recommendations to improve ICS programs.

Recent progress in the application of biodegradable metal implants

With the accumulation of data, magnesium-based degradable metal, iron-based degradable metal and zinc-based degradable metal implantable interventional devices have entered the clinic or carried out human experimental studies, and the future prospects are promising. In this paper, the definition, biodegradability and biocompatibility criteria and their classification are reviewed, and the research status and unsolved scientific problems of magnesium-based degradable metals, iron-based degradable metals and zinc-based degradable metals are introduced, and the future development opportunities and challenges of degradable metals are prospected. With a deeper understanding of scientific issues such as mechanical adaptation, degradation adaptation and tissue adaptation of degradable metal implants, more new materials, new technologies and new methods of degradable metals will be developed in the future, so as to effectively realize the precise adaptation of the two events of degradable metal material degradation and body tissue repair in time and geometric space.

Fabrication and Investigation of Deformable Rubber-Carbon Nanotube-Glue Gel-Based Impedimetric and Capacitive Tactile Sensors for Pressure and Displacement Measurements.

Carbon nanotube-glue composite gel-based surface-type elastic sensors with a cylindrical shape deformable (flexible) metallic body were fabricated for tactile pressure and compressive displacement sensing. The fabrication of the sensors was performed using the rubbing-in technique. The effect of the pressure and the compressive displacement on the capacitance and the impedance of the sensors were investigated at various frequencies (in the range of 1 kHz to 200 kHz). It was found that under the effect of pressure from 0 to 9 g/cm2, the capacitance increased by 1.86 and 1.78 times, while the impedance decreased by 1.84 and 1.71 times at the frequencies of 1 kHz to 200 kHz, respectively. The effect of displacement on the impedance and the capacitance of the device was also investigated at various frequencies from 1 kHz to 200 kHz. The results showed that under the effect of compressive displacement up to 25 µm, the impedance of the sensors decreased on average by 1.19 times, while the capacitance increased by 1.09 times, accordingly. The frequency response of the displacement sensor showed that it matched with the low-pass filter. The obtained results are explained based on changes in the shape and geometrical parameters of the cylindrical-shaped conductive body. These results have also been explained on the basis of the distance between the conductive plates of the capacitive sensors during compression, which takes place under the effect of applied pressure or displacement. Moreover, the design of the sensors is simple and easy to fabricate, and their use is also earthy. The fabricated sensors have great potential for commercialization.

Impact dynamics of a free-falling reference test mass in space

Outer space may constitute a privileged environment for experiments involving impacts. In fact, disturbing phenomena like drag or weight forces are negligible and a nearly pure free-fall state may be achieved for the impacting bodies. The case analysed in this manuscript comes from the initialization of the science phase of a space mission (LISA Pathfinder, flown in 2015), in which an extended metallic body – starting from a caged configuration – was released to free-fall inside a spacecraft by a dedicated mechanism, the grabbing positioning and release mechanism (GPRM). During the release phase, the test mass (TM) experienced some impacts with the GPRM end effector, before being electrostatically controlled to its nominal position, i.e. still in the centre of the hosting electrode housing. The impact dynamics of the TM therefore resulted critical, since it helped reduce its kinetic energy with respect to the spacecraft. In this paper, the TM position and attitude telemetry signals are analysed, and the impacts coefficient of restitution is calculated, providing reference values for similar space instruments, where a free-falling reference body is used (for instance, for geodesy and/or spacecraft navigation).

Intraoperative magnet in removal of intracerebral metallic foreign bodies

Advisability of magnets in neurotrauma is due to pattern of patients admitted to neurosurgical departments of military hospitals with wounds accompanied by intracranial fixation of foreign metallic ferromagnetic bodies. To study dimensions, mass and magnetic properties of fragments extracted from gunshot wounds inflicted by modern weapons; to assess the feasibility of devices and instruments for removing foreign bodies. We analyzed foreign bodies extracted after gunshot wounds. Shape, dimension, weight and magnetic properties were studied. We estimated 532 foreign bodies (497 surgeries) extracted at the Kirov Military Medical Academy and 83 foreign bodies (79 surgeries) extracted at the Burdenko Military Clinical Hospital. Distribution by anatomical regions was established for both groups. We intraoperatively used cylindrical neodymium magnets 3×20 and 5×20 mm to extract magnetic foreign bodies. These magnets were brought to the target using standard surgical tweezers or original devices. The median mass of removed fragments was 0.385 (Q1-Q3=0.12-1.435; min-max≤0.01-30.5) g at the Kirov Military Medical Academy and 0.4 (Q1-Q3≤0.001-1.6; min-max≤0.01-11.4) g at the Burdenko Military Clinical Hospital. Magnetic foreign bodies were found in 501 (94.2%) and 74 (94.8%) cases, respectively. In 8.8% of cases, foreign bodies were not removed due to difficult-to-reach location accompanied by higher risk of adverse outcomes after extraction. Extracted foreign bodies after combat injuries have magnetic properties in 94% of cases. Intraoperative magnet allows for safe extraction of fragments in 91% of cases. Devices with adjustable magnetic field strength seem perspective. Further analysis of indications for removal of wounding projectiles in primary and, especially, repeated surgical treatment of craniocerebral wounds is needed.

Structural Determination of Zn2+, Cu2+, and Fe2+ Complexed with Glutathione by IRMPD Spectroscopy and Complimentary ab Initio Calculations

Glutathione is a biologically abundant and redox active tripeptide that serves to protect cells from oxidative stress and rid the body of toxic heavy metals. The present study examines the...

РАЗРАБОТКА МАТЕМАТИЧЕСКОЙ МОДЕЛИ КОЛЕБАТЕЛЬНЫХ ПРОЦЕССОВ ПРИ ТОКАРНОЙ ОБРАБОТКЕ МАТЕРИАЛОВ С ОБРАТНЫМ РАСПРЕДЕЛЕНИЕМ ТВЕРДОСТИ

For technological guarantee of the required quality indicators of the surface layer of metallic rotation body parts at finishing machining needs the correct assignment of technological modes. During finishing turning, vibrational processes have a significant (and often decisive) effect on the formation of surface roughness. It is necessary to choose such values of technological modes, which provide an acceptable level of vibration (previously it is advisable to solve this problem by modelling). Mathematical model was carried out based on the determination of the turning tool deformations under the influence of cutting forces. To determine the amplitudes of the cutter oscillations, the Mohr integral was used, and the amplitude-frequency characteristics were determined using the Duhamel integral. Cutting forces were determined taking into account the shape and nature of chip formation, the value of technological modes and processing conditions. As the material to be machined, the authors considered the cast iron with a layer hardened by diffusion alloying. Determination of input data for model was carried out directly during machining on the lathe and with the help of measurements of chip parameters. As cutting tools, we used standard cutters with mechanically fastened plates. The evaluation of the modelling results showed high convergence with the experimental results: the error in amplitude was 8.5 percent, in oscillation frequency - 12.3 percent; in general, the error did not exceed 15 percent. Thus, the developed model can be used for preliminary vibration assessment at the design stage of turning operations.

Power Distribution Technology based on Transmission of Power Packets via Conducting Metal Body

Power Distribution Technology based on Transmission of Power Packets via Conducting Metal Body

Computation of Characteristic Mode for Regional Structure of Interconnected Metal Bodies

Computation of Characteristic Mode for Regional Structure of Interconnected Metal Bodies

INSIGHT INTO THE OXIDATIVE DEGRADATION OF PHENOLIC RESIN DESTINED FOR THE CORROSION PROTECTION OF METALLIC SURFACES

The effects on the stability under accelerated degradation of phenolic resin used for the corrosion inhibition of metallic surfaces in aeronautical and nuclear spare parts are evaluated by nonisothermal chemiluminescence (CL) at four different heating rates: 5, 10, 15, and 20 ⁰C min-1. The simulation of the interface interaction between the metallic bodies and protection layers is achieved by the addition of metallic oxides as corrosion promoters: Gd2O3, CeO2, Pr2O3, MgO, MnO2, Cr2O3, and In2O3. These metallic atoms may be the main alloying elements that are present in the compositions of special application products. The presence of a specific peak in the CL spectra between 160 and 177°C proves the oxidation activity of filler in the connection of electronic interference. The differences between the emission intensities of the studied formulations certify the unlike contributions of alloying components. The heating rate plays also the role of oxidation factor that influences the refreshing surrounding atmosphere. The present results define the thermal technological limits of peculiar operation conditions for any metallic item subjected to a high level of warranty. The initiation of degradation in phenolic resin is done by -irradiation when free fragments are provided for the interaction with metallic structures. The development of oxidation is analyzed by the modification of CL emission intensities from room temperature to 250°C. The diminution of this process parameter over 200°C is found an essential factor for the preservation of surface integrity.

Global studies in waste management in mechanical workshops: evolution and future perspectives in the search for good practices

The environmental impacts that we are currently facing worldwide are due to a system that uses all available resources as if they were unlimited and therefore an uncontrolled amount of garbage has been generated that is causing damage to the environment and consequently to human health. . In search of solutions to these problems, new ways of managing waste have been implemented, which are often not applied due to lack of knowledge of them. Mechanical shops offer a variety of services, from tire repairs to collision services, whether for light or heavy vehicles, or promote maintenance of mechanical systems in general. These services generate several types of solid waste , including rags contaminated with oils or solvents, plastic containers, old tires, oil, transmission or air filters; plastic and metal body parts, batteries, glass and residual sludge, mostly hazardous waste. In this context, the objective of the article was to carry out a scientific mapping on waste management in mechanical workshops, and in search of good practices. For this, a quantitative and qualitative bibliometrics was carried out. The results indicate that life cycle analysis is the most appropriate tool to define the best use of the waste generated (co-products), followed by management systems and tools and cleaner production. Continuous staff training is essential; to maintain more efficient processes that present returns within each business. The adoption of environmental or management certifications is a big step within each business, but in small mechanical workshops, good waste management is quite sufficient and significant.