Standard Laboratory Experiments Research Articles

Computational Geodynamics Laboratory: 15 years of numerical modeling and high-performance computing at the Centro de Geociencias, Universidad Nacional Autónoma de México

The rapid development of computer technology in the last decades provided scientists with new opportunities to expand their research fields and in the same time to compress the necessary time to obtain research based scientific conclusions. This fast tendency also significantly affected the scientific discovery trend, and in many research fields we observe a transition from standard laboratory experiments to numerical experiments. In the particular research field of Earth Sciences, computational modeling constitutes a powerful predictive tool that fills a geological and geophysical data gap. The geological record covers well the Earth’s surface but is quite limited in depth, whereas geophysical information can provide depth-based information but it is limited in time to present day. Therefore, there is a large data gap in time and space that cannot be covered unless some indirect and intuitive prediction method is used. In this picture, numerical simulations come as an essential research tool. In this work, we provide a review about the research progress obtained in the last 15 years using high-performance computing at the Computational Geodynamics Laboratory at the Centro de Geociencias, Universidad Nacional Autónoma de México.

Insights into the Fabrication and Electrochemical Aspects of Paper Microfluidics-Based Biosensor Module.

Over the past ten years, microfluidic paper-based analytical devices (micro-PADs) have attracted a lot of attention as a viable analytical platform. It is expanding as a result of advances in manufacturing processes and device integration. Conventional microfluidics approaches have some drawbacks, including high costs, lengthy evaluation times, complicated fabrication, and the necessity of experienced employees. Hence, it is extremely important to construct a detection system that is quick, affordable, portable, and efficient. Nowadays, micro-PADs are frequently employed, particularly in electrochemical analyses, to replicate the classic standard laboratory experiments on a miniature paper chip. It has benefits like rapid assessment, small sample consumption, quick reaction, accuracy, and multiplex function. The goal of this review is to examine modern paper microfluidics-based electrochemical sensing devices for the detection of macromolecules, small molecules, and cells in a variety of real samples. The design and fabrication of micro-PADs using conventional and the latest techniques have also been discussed in detail. Lastly, the limitations and potential of these analytical platforms are examined in order to shed light on future research.

Remeshing‐free Graph‐based Finite Element Method for Fracture Simulation

AbstractFracture produces new mesh fragments that introduce additional degrees of freedom in the system dynamics. Existing finite element method (FEM) based solutions suffer from increasing computational cost as the system matrix size increases. We solve this problem by presenting a graph‐based FEM model for fracture simulation that is remeshing‐free and easily scales to high‐resolution meshes. Our algorithm models fracture on the graph induced in a volumetric mesh with tetrahedral elements. We relabel the edges of the graph using a computed damage variable to initialize and propagate fracture. We prove that non‐linear, hyper‐elastic strain energy density is expressible entirely in terms of the edge lengths of the induced graph. This allows us to reformulate the system dynamics for the relabelled graph without changing the size of the system dynamics matrix and thus prevents the computational cost from blowing up. The fractured surface has to be reconstructed explicitly only for visualization purposes. We simulate standard laboratory experiments from structural mechanics and compare the results with corresponding real‐world experiments. We fracture objects made of a variety of brittle and ductile materials, and show that our technique offers stability and speed that is unmatched in current literature.

It's all about food: Environmental factors cause species‐specific dispersal

AbstractDispersal is a vital component of the life history of nearly all organisms. The ability to disperse determines the distribution and abundance of a species and thus its community dynamic at different sites. The scientific challenge is to design standardized laboratory experiments that not only record the effects of single factors but also include the multicausal nature of dispersal. Here we tested the effect of the environmental factors density, food availability and predation, and the combinations thereof on the dispersal of five free‐living nematode species by performing experiments in two‐patched systems. We hypothesized that emigration is generally positively correlated with the intrinsic rate of natural increase and would decrease with increasing food availability and increase both with the presence of a predator and at higher initial population densities. These predictions were tested both using single‐species tests with laboratory cultures and using intact natural nematode communities to investigate whether environmental factors determine the composition of dispersing species. The results of our study revealed a positive correlation between dispersal and intrinsic growth ability, whereas the studied nematode species differed in their dispersal patterns, both under control conditions and in response to bottom‐up, top‐down, and density‐dependent stimuli. Despite the species‐specific differences in dispersal behavior in response to the environmental factors, the availability of food appeared as the main driver. This was particularly pronounced regarding a natural nematode community. Our experiments emphasize the central role of food availability in spatial structuring nematode communities.

Microbiological safety of traditionally processed fermented foods based on raw milk, the case of Mabisi from Zambia

For centuries, perishable raw materials such as raw milk have been processed through traditional fermentation. For many, microbiological safety has not been assessed systematically. Here, we study the microbiological safety of an archetypical traditional fermented raw milk product with high cultural importance: Mabisi from Zambia. We focus on traditional processing without the use of defined starter culture – a method that is employed by local small-scale processors at home or at farmer cooperatives. In a field survey, we found that food associated pathogenic bacteria such as Salmonella sp. and Staphylococcus aureus were present in raw milk used for processing. In processed Mabisi these pathogens were found to be present albeit at levels that fall below common limits of microbiological safety for dairy products. In standardized laboratory experiments, we investigated the microbiological safety of traditionally processed Mabisi using challenge tests with important pathogens related to raw milk and Mabisi. Strains of S. aureus, Salmonella and Listeria monocytogenes could survive fermentation and were present in the end-product after 48 or 72 h of fermentation, yet below legally set thresholds of acceptability. Our work shows that use of traditional processing methods for fermentation of raw milk can result in products that are microbiologically safe.

Suitability of Saw Dust Ash and Quarry Dust as Mineral fillers in Asphalt Concrete

This study attempts to justify how suitable a conventional mineral filler and a non-conventional mineral filler can replace fractions of the aggregates in an asphalt concrete in order to reduce cost and encourage reuse of waste materials. Asphalt concrete mix proportions were generated with 3% Quarry Dust and 3% Saw Dust Ash replacements of aggregates. The binder contents were 3, 4, 5, 6 and 7% for a 60/70 penetration grade asphalt binder. Briquette specimens were formed using the asphalt concrete mix proportions carried out. Standard laboratory experiments were carried out on the aggregates, Quarry Dust, Saw Dust Ash, bituminous binder and asphalt concrete specimens based on the relevant codes and standards. The Marshall method was used for the asphalt concrete design procedure. The optimum binder content was found to be 4.85% using the standard Marshall curves. At optimum binder content, using 4% design air void for medium traffic and maximum aggregate of 10mm, the Stability, Flow, VMA and VFA were 5.83kN, 15.73(0.25mm), 15.28% and 73.25% respectively. These were within the Asphalt Institute design criteria.

A weight of evidence approach for bioaccumulation assessment.

Bioaccumulation assessments conducted by regulatory agencies worldwide use a variety of methods, types of data, metrics, and categorization criteria. Lines of evidence (LoE) for bioaccumulation assessment can include bioaccumulation metrics such as in vivo bioconcentration factor (BCF) and biomagnification factor (BMF) data measured from standardized laboratory experiments, and field (monitoring) data such as BMFs, bioaccumulation factors (BAFs), and trophic magnification factors (TMFs). In silico predictions from mass-balance models and quantitative structure-activity relationships (QSARs) and a combination of in vitro biotransformation rates and in vitro-in vivo extrapolation (IVIVE) models can also be used. The myriad bioaccumulation metrics and categorization criteria and underlying uncertainty in measured or modeled data can make decision-making challenging. A weight of evidence (WoE) approach is recommended to address uncertainty. The Bioaccumulation Assessment Tool (BAT) guides a user through the process of collecting and generating various LoE required for assessing the bioaccumulation of neutral and ionizable organic chemicals in aquatic (water-respiring) and air-breathing organisms. The BAT includes data evaluation templates (DETs) to critically evaluate the reliability of the LoE used in the assessment. The DETs were developed from standardized testing guidance. The approach used in the BAT is consistent with OECD and SETAC WoE principles and facilitates the implementation of chemical policy objectives in chemical assessment and management. The recommended methods are also iterative and tiered, providing pragmatic methods to reduce unnecessary animal testing. General concepts of the BAT are presented and case study applications of the tool for hexachlorobenzene (HCB) and β-hexachlorocyclohexane (β-HCH) are demonstrated. The BAT provides a consistent and transparent WoE framework to address uncertainty in bioaccumulation assessment and is envisaged to evolve with scientific and regulatory developments.Integr Environ Assess Manag 2023;19:1235-1253. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Field test of the TOXSWA pesticide fate model: Comparison of simulated and observed chlorpyrifos in water, sediment and macrophytes in four stagnant ditches

TOXSWA is a numerical model describing pesticide behavior in an edge-of-field waterbody. It is widely used to predict exposure in regulatory risk assessment for aquatic ecosystems. Exposure concentrations are predicted based upon pesticide process parameters obtained in standardized laboratory experiments. However, few tests of the model performance based on field data have been carried out. We compare simulated concentrations to observations from a field experiment with four shallow stagnant ditches over sprayed with chlorpyrifos, a moderately volatile pesticide with a significant sorption capacity. Input parameters describing the four ditches, such as dimensions, water depth, sediment and macrophyte characteristics were measured in detail. Additionally, laboratory experiments were carried out to determine site-specific values for parameters describing chlorpyrifos degradation in water and sediment, as well as sorption to the two dominant macrophyte species. Based upon these estimated parameters, the correspondence between simulated and measured concentrations in water, sediment and macrophytes is poor. We attribute this discrepancy to a lack of site-specific input for the processes of volatilization and sorption to sediment, which both are important processes for chlorpyrifos. Therefore, we calibrated TOXSWA using the optimization tool PEST. The transfer coefficient for volatilization and the coefficient for sorption to sediment were optimized based on the observed concentrations in water and sediment. This resulted in a substantial improvement of correspondence. Optimized values of the transfer coefficient for volatilization and the coefficient for sorption to sediment are substantially higher than their initial estimates (4–8-fold and 2–4-fold increase, respectively), but can be well explained. The optimized coefficients vary less than a factor 2 between the four ditches. We conclude that TOXSWA can adequately predict chlorpyrifos behavior in the four ditches, provided that reliable site-specific parameter estimates are available. Field tests for other pesticides, waterbodies and agro-environmental conditions are warranted.

Y-Mat: an improved hybrid finite-discrete element code for addressing geotechnical and geological engineering problems

PurposeContinua and discontinua coexist in natural rock materials. This paper aims to present an improved approach for addressing the mechanical response of rock masses based on the combined finite-discrete element method (FDEM) proposed by Munjiza.Design/methodology/approachSeveral algorithms have been programmed in the new approach. The algorithms include (1) a simpler and more efficient algorithm to calculate the contact force; (2) An algorithm for tangential contact force closer to the actual physical process; (3) a plastic yielding criterion (e.g. Mohr-Coulomb) to modify the elastic stress for fitting the mechanical behavior of elastoplastic materials; and (4) a complete code for the mechanical calculation to be implemented in Matrix Laboratory (MATLAB).FindingsThree case studies, including two standard laboratory experiments (uniaxial compression and Brazilian split test) and one engineering-scale anti-dip slop model, are presented to illustrate the feasibility of the Y-Mat code and its ability to deal with multi-scale rock mechanics problems. The results, including the progressive failure process, failure mode and trajectory of each case, are acceptable compared to other corresponding studies. It is shown that, the code is capable of modeling geotechnical and geological engineering problems.Originality/valueThis article gives an improved FDEM-based numerical calculation code. And, feasibility of the code is verified through three cases. It can effectively solve the geotechnical and geological engineering problems.

Development of a sticker sealed microfluidic device for in situ analytical measurements using synchrotron radiation

Shedding synchrotron light on microfluidic systems, exploring several contrasts in situ/operando at the nanoscale, like X-ray fluorescence, diffraction, luminescence, and absorption, has the potential to reveal new properties and functionalities of materials across diverse areas, such as green energy, photonics, and nanomedicine. In this work, we present the micro-fabrication and characterization of a multifunctional polyester/glass sealed microfluidic device well-suited to combine with analytical X-ray techniques. The device consists of smooth microchannels patterned on glass, where three gold electrodes are deposited into the channels to serve in situ electrochemistry analysis or standard electrical measurements. It has been efficiently sealed through an ultraviolet-sensitive sticker-like layer based on a polyester film, and The burst pressure determined by pumping water through the microchannel(up to 0.22 MPa). Overall, the device has demonstrated exquisite chemical resistance to organic solvents, and its efficiency in the presence of biological samples (proteins) is remarkable. The device potentialities, and its high transparency to X-rays, have been demonstrated by taking advantage of the X-ray nanoprobe Carnaúba/Sirius/LNLS, by obtaining 2D X-ray nanofluorescence maps on the microchannel filled with water and after an electrochemical nucleation reaction. To wrap up, the microfluidic device characterized here has the potential to be employed in standard laboratory experiments as well as in in situ and in vivo analytical experiments using a wide electromagnetic window, from infrared to X-rays, which could serve experiments in many branches of science.

Himic Anhydride: A Retro Diels-Alder Reaction for the Organic Laboratory and an Accompanying NMR Study.

The thermal equilibration of himic anhydride [IUPAC (2-endo,3-endo)-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid anhydride] to (2-exo,3-exo)-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid anhydride and subsequent recrystallization of the exo-product can be performed as a standard undergraduate laboratory experiment requiring minimal equipment. The interpretation of the 1H NMR spectra for these norbornene carboxylic anhydride molecules promotes an appreciation of constrained ring systems and factors that affect chemical shifts and coupling constants.

Does Additive Pressurized Carbon Dioxide Lavage Improve Cement Penetration and Bond Strength in Cemented Arthroplasty?

The modern cementing technique in cemented arthroplasty is a highly standardized and, therefore, safe procedure. Nevertheless, aseptic loosening is still the main reason for revision after cemented total knee or cemented total hip arthroplasty. To investigate whether an additional carbon dioxide lavage after a high-pressure pulsatile saline lavage has a positive effect on the bone–cement interface or cement penetration, we set up a standardized laboratory experiment with 28 human femoral heads. After a standardized cleaning procedure, the test implants were cemented onto the cancellous bone. Subsequently, the maximum failure load of the bone–cement interface was determined using a material testing machine to pull off the implant, and the cement penetration was determined using computed tomography. Neither the maximum failure load nor cement penetration into the cancellous bone revealed significant differences between the groups. In conclusion, according to our experiments, the additive use of the carbon dioxide lavage after the high-pressure pulsatile lavage has no additional benefit for the cleaning of the cancellous bone and, therefore, cannot be recommended without restrictions.

The Transformation by Catalysis of Prebiotic Chemical Systems to Useful Biochemicals: A Perspective Based on IR Spectroscopy of the Primary Chemicals: Solid-Phase and Water-Soluble Catalysts

This study is a continuation of our research on understanding the possible chemical routes to the evolution of life on earth based on the “Selective Energy Transfer” (SET) theory. This theory identifies the specific vibrational mode of the catalyst that is in energy-resonance with a suitable vibrational mode of the reactant. In this way, energy is transferred from catalyst to reactant up to the energy of activation, making possible a particular chemical outcome. Then, we extend this model to the mostly unknown and highly complex environment of the hydrothermal vents, to speculate how prebiotic chemicals, necessary for the evolution of life, could have formed. It is to the credit of the SET theory that it can reflect the slight difference in the catalytic system that gives dramatically very different chemical outcome. It is shown, here, how in model laboratory experiments, methanol gives dimethyl ether (DME) in a 100% yield with Cu exchanged montmorillonite as the catalyst, or a very different product methyl formate (MF) in lower yields, with another Cu2+ ion-exchanged clay mineral (laponite) as the catalyst system. We also show, based on standard laboratory experiments, how COS (carbonyl sulfide) with a strong absorption band at 2079 cm−1 by itself and/or catalyzed by montmorillonite with strong Si-O-Si asymmetric vibration of 1040 cm−1 can react with alpha-amino acids to form alpha-amino acid thiocarbamate (AATC), which we feel could represent the most primitive analogue to coenzyme A (CoASH), a highly versatile bio-enzyme that is vital both for the metabolism and the synthesis of biochemicals in the living system. AATC itself may have undergone evolutionary developments through billions of years to transform itself into coenzyme A (CoASH) and its acetyl ester analogue acetyl coenzyme A (ACoA).

Использование модельных объектов при оценке эффективности репеллентных средств на основе ДЭТА для индивидуальной защиты от кровососущих членистоногих

With the aim of unifying and simplifying the assessment of categories of the effectiveness of the repellents funds audited 473 studies 245 samples of repellent remedies on the basis of DEET in various formulations, made in 1995–2019 employees of the Scientific Research Disinfесtology Institute in laboratory and in field conditions. The experiments were conducted in parallel with the standards of the corresponding or expected categories of effectiveness of repellent remedies. The concordance of the results of standard laboratory experiments on a model object Ae. aegypti mosquitoes and the results obtained from testing repellent agents against natural populations of flying blood-sucking insects and taiga ticks is proved. The effectiveness of repellent remedies based on other repellent substances, as well as the effectiveness against other species, should continue to be investigated in full-scale conditions for individuals of natural populations. These remedies should be included in the system of categories of effectiveness of repellent products.

Characterisation of Saw Dust Ash – Quarry Dust Bituminous Concrete

This study evaluates usefulness of Quarry Dust and Saw Dust Ashas mineral fillers in a bituminous concrete in order to reduce cost and encourage reuse of waste materials in the environment. Bituminous concrete blends were generated with 4% Quarry Dust and 4% Saw Dust Ash replacements of aggregates. The binder contents were 3, 3.5, 4, 4.5 and 5% for a 60/70 penetration grade bituminous binder. Briquette specimens were formed using the five different bituminous concrete blends. Standard laboratory experiments were conducted on the aggregates, Quarry Dust, Saw Dust Ash, bituminous binder and bituminous concrete specimens based on the relevant codes and standards. The Marshall method was used for the bituminous concrete design procedure. The optimum binder content was found to be 4.88% using the standard Marshall curves. At optimum binder content, using 4% design air void for medium traffic and maximum aggregate of 10mm, the Stability, Flow, VMA and VFA were 8.15kN, 8.28(0.25mm), 15.22% and 74.2% respectively. These were found to have passed the Asphalt Institute design criteria.

Effects of salinity and rock clogging on injectivity dynamics of flooding wells: Experiments, modeling and validation on field data

Injection of water into a rock formation is a common oilfield services technology to maintain high reservoir pressure and increase ultimate recovery of hydrocarbons. While flowing through the well from surface to the rock formation, injected water typically transports fine particles, for example, fine sand grains and calcite precipitated at surface pipeline conditions while mixing water from different sources (e.g., fresh, Cenomanian and formation brine). In the framework of the two-fluid approach to suspension flow modelling, we formulate mathematical model for linear filtration of a particle-laden suspension in the vicinity of a fractured flooding well and transport of ion concentration (salinity). Two major factors of well injectivity decline are described, namely, particle trapping with associated reduction in permeability and porosity of the rock as well as the effect of salinity of injecting water leading to clay swelling, calcite precipitation and change of relative permeabilities of the rock with respect to water and oil. We calibrate suspension filtration model against in-house experiments on clogging of artificial and natural rock cores, in which the profiles of fines concentration along the cores are obtained using X-Ray computed tomography and analysis of 3D rock reconstruction images. The water injection model is adopted to conditions of Priobskoye oilfield of Western Siberia by using the results of standard laboratory experiments on fluid-fluid (calcite precipitation) and fluid-rock (clay swelling, migration of internal fines) compatibility, as well as the effect of salinity on oil displacement and analysis of solid fraction in the injecting water. The calibrated model is then used to describe field data on dynamics of injection rate of three flooding wells. It is obtained that the simulations predict the long-term injectivity dynamics of the wells very well, while at early times (up to 5 months from the start of injection) the model underestimates the injection rate. While fitting the model to field data, we varied only two parameters, namely, solids concentration in the injecting water (in the range provided by lab experiments) and trapping coefficient (the range is limited to result of experiments made with target rock cores). It is demonstrated that only a combination of injectivity decline factors allows to describe the long-term flooding rate of the wells. Ignoring either particle trapping or salinity effects lead to significant overestimation (up to 50%) of the long-term injection rate. Parametric study of water injection showed that two-fold increase in solids concentration in the injecting water as well as oil compressibility lead to similar decrease in long-term injection rate of a well.

Asymptotics of inverse filtration problem in porous media

Filtration problems arise in the design of tunnels and underground structures. A one-dimensional filtration model of a monodisperse suspension in a homogeneous porous medium is considered. For a general nonlinear filtration function, an asymptotic solution is constructed behind the concentrations front of suspended and retained particles. It is shown that the asymptotics is close to the numerical solution. Comparison of the asymptotics with the suspended particles concentration at the outlet of the porous medium allows solving the inverse filtration problem on finding the nonlinear filtration function. The proposed method allows to obtain the filtration function based on the results of standard laboratory experiments.

Positive Correlation between Pesticide Consumption and Longevity in Solitary Bees: Are We Overlooking Fitness Trade-Offs?

Simple SummaryThe possible impacts of neonicotinoids combined with glyphosate-based herbicides on bees are unknown. Here, we show no effects of chronic exposure to field-realistic dosages of Roundup® and clothianidin alone or combined on food consumption and cumulative survival of adult female bees, Osmia bicornis in the laboratory. However, a positive correlation between exposure and longevity was revealed. Our data suggest a possibly neglected trade-off between survival and reproduction in insect toxicology.The ubiquitous use of pesticides is one major driver for the current loss of biodiversity, and the common practice of simultaneously applying multiple agrochemicals may further contribute. Insect toxicology currently has a strong focus on survival to determine the potential hazards of a chemical routinely used in risk evaluations. However, studies revealing no effect on survival or even indicating enhanced survival are likely to be misleading, if potential trade-offs between survival and other physiological factors are overlooked. Here, we used standard laboratory experiments to investigate the sublethal (i.e., food consumption) and lethal (i.e., survival) effects of two common agricultural pesticides (Roundup® and clothianidin) on adult female solitary bees, Osmia bicornis. The data showed no significant effect of the treatment on cumulative survival; however, a significant positive correlation between herbicide and insecticide exposure and age was revealed, i.e., bees exposed to higher dosages lived longer. As no significant differences in daily food consumption were observed across treatment groups, increased food intake can be excluded as a factor leading to the prolonged survival. While this study does not provide data on fitness effects, two previous studies using solitary bees observed significant negative effects of neonicotinoid insecticides on fitness, yet not on survival. Thus, we conjecture that the observed non-significant effects on longevity may result from a trade-off between survival and reproduction. The data suggest that a focus on survival can lead to false-negative results and it appears inevitable to include fitness or at least tokens of fitness at the earliest stage in future risk assessments.

Turbulent Energy Spectrum via an Interaction Potential

For a large system of identical particles interacting by means of a potential, we find that a strong large scale flow velocity can induce motions in the inertial range via the potential coupling. This forcing lies in special bundles in the Fourier space, which are formed by pairs of particles. These bundles are not present in the Boltzmann, Euler and Navier-Stokes equations, because they are destroyed by the Bogoliubov-Born-Green-Kirkwood-Yvon formalism. However, measurements of the flow can detect certain bulk effects shared across these bundles, such as the power scaling of the kinetic energy. We estimate the scaling effects produced by two types of potentials: the Thomas-Fermi interatomic potential (as well as its variations, such as the Ziegler-Biersack-Littmark potential), and the electrostatic potential. In the near-viscous inertial range, our estimates yield the inverse five-thirds power decay of the kinetic energy for both the Thomas-Fermi and electrostatic potentials. The electrostatic potential is also predicted to produce the inverse cubic power scaling of the kinetic energy at large inertial scales. Standard laboratory experiments confirm the scaling estimates for both the Thomas-Fermi and electrostatic potentials at near-viscous scales. Surprisingly, the observed kinetic energy spectrum in the Earth atmosphere at large scales behaves as if induced by the electrostatic potential. Given that the Earth atmosphere is not electrostatically neutral, we cautiously suggest a hypothesis that the atmospheric kinetic energy spectra in the inertial range are indeed driven by the large scale flow via the electrostatic potential coupling.

Influence of reagent dose on the flotation selectivity of copper ore from LGOM area (SW Poland)

The influence of amount of flotation reagents on the efficiency of copper ore flotation in standard laboratory experiments was investigated. The aim of the study was to evaluate the effect of collector and frother amount on the selectivity of copper upgrading during flotation process of dolomite-shale ore from Fore-Sudetic Monocline area (Legnica-Glogow Copper Basin). The amount of collectors added in industrial conditions was the starting point for the process assessment. Since the dose of flotation reagents influences on the quality and quantity parameters of obtained concentrates, a decrease or increase of reagent dosage can have a major impact on the overall metal production costs at the mining-metallurgical complex.