Permissible Values Research Articles

Assessment of Heavy Metal Contamination and Risk Associated with Quarrying Activities in Marksino Concession Area, Akamkpa

This study evaluates the environmental risks of quarrying activities in the Marksino Concession area, Akampka, with a focus on heavy metal contamination of the soil. Soil samples were collected at various distances from the quarry site and analyzed using atomic absorption spectrophotometry (FAAS; PG990) to determine concentrations of lead, chromium, copper, cadmium, cobalt, nickel, arsenic, and zinc. Pollution indices and ecological risk factors were calculated, along with hazard quotients and indices for non-carcinogenic impacts on children and adults. Results indicate that contamination values for all metals were below one, suggesting no significant impact at the sampling points. The geo-accumulation index values also indicated no significant impact for all metals. Furthermore, hazard quotient (HQ) and hazard index (HI) values for all metals were below the permissible value of 1, indicating non-carcinogenic risks for residents. However, children showed higher HI values compared to adults, emphasizing the need for targeted measures to protect this vulnerable group. Continuous monitoring and mitigation efforts are crucial for sustainable quarrying activities and prevention of environmental hazards in the Marksino Concession area.

Audit Dan Peluang Penghematan Energi Listrik CV Tirta Windu Agung 3 Probolinggo

The use of electrical energy in the building and industrial sectors is very important, especially the use and allocation of funds spent is quite large. So it is necessary to use energy as efficiently as possible. So there is a need for an energy audit to determine the level of electrical energy consumption used, where the results will be compared with predetermined standards. This research was carried out at CV Tirta Windu Agung 3 using a PM5100 and lux meter. From initial audit calculations, the IKE value was found to be 13.42 kWh/m2/year. This IKE value is the total of the buildings and ponds. The IKE value still includes very efficient criteria. Based on the results of detailed audit calculations, the value obtained before improvement was 2.23 kWh/m2/year. The IKE value still includes the criteria for being very efficient or meeting standards. After improvements it became 1.65 kWh/m2/year. Energy saving opportunities are available in indoor and outdoor lighting systems by replacing CFL (compact fluorescent lamp) lamps with Philips LED lamps. Based on calculations, the savings in electrical energy costs are IDR 41,736/day, resulting in savings of IDR 15,233,640/year. Based on the Isc/IL calculation above, it can be seen that the Isc/IL value is 165.4. According to the IEEE 519-2014 standard, the ISC IL value in the range >1000 has a permissible THDi value limit of 15%. The nominal voltage used is 0.4 kV, so the permitted THDv is 8%. Based on table 3.9 THDv and THDi under standard conditions.

Arsenic in a Karstic Paddy Soil with a High Geochemical Background in Guangxi, China: Its Bioavailability and Controlling Factors

Arsenic (As) is of widespread concern, as its elevated contents in soil and water have a serious impact on the ecological environment and human health. Soils in karst regions are characterized by a high geochemical background of As. However, the bioavailability of As in paddy soils and the potential risk of As transfer from the soil to rice remain unclear. In this study, 305 paired soil–rice samples were collected from karst regions in Guangxi, China, in order to examine the controlling variables and As bioavailability in the soil–rice system. According to this study, the karst region’s paddy soil had higher As concentrations than the non-karst region’s paddy soil. The As concentration in the rice grains was low, with only 0.62% of the rice samples exceeding the permissible value of inorganic As (0.2 mg/kg). Arsenic in the karstic paddy soils existed mainly in the residual fraction, while the water-soluble and exchangeable fractions, which are readily absorbed by rice, accounted for a relatively small proportion. The high content but low bioavailability of As in the karstic paddy soil was mostly attributed to the abundant Fe–Mn nodules, which contributed 64.45% of the As content in the soil. Within the Fe–Mn nodules, As was primarily bound to Fe-(oxyhydr)oxides, which could be released into the paddy soil under certain reduction conditions via the reductive dissolution of Fe-(oxyhydr)oxides. Under the natural pH conditions of the karstic paddy soil (pH 4.9–8.38), the leaching of As was almost negligible, and As could be steadily retained within the Fe–Mn nodules. However, extremely acidic or alkaline conditions promoted the release of As from the Fe–Mn nodules.

Geophysical and Geotechnical Investigations of the Subsurface for Construction Purposes at Federal College of Education Osiele, Abeokuta, Southwestern Nigeria

Knowledge of the surface and subsurface structures are vital for construction procedures. Integrated geophysical and geotechnical methods were applied to image the subsurface for evaluation of the stratigraphy and the competency of each geoelectric layer for construction purposes at the Federal College of Education Osiele, Abeokuta South-western Nigeria. Nine Vertical Electrical Sounding (VES) using Schlumberger electrode configurations were conducted over a current electrode spacing of 200 m. Multi-channel Analysis Surface Wave (MASW) was the seismic technique used for the geotechnical analysis of the study area and laboratory analysis was performed to investigate, Atterberg limit, particle size distribution, compaction test, specific gravity, and California bearing ratio. Results from the geophysical investigation revealed four to five geoelectric layers: topsoil, clayey sand, sandy clay, laterite, and fresh basement. The MASW results have s-wave velocities range of 40–500 m/s and analysis showed four layers. The laboratory analysis revealed that all the ten traverses have specific gravity, which is out of limit except sample 8 which is 2.80, plastic index and Atterberg limits of liquid were within permissible values of 12% and 35% respectively except samples 9 and 10, and California Bearing Ratio within specified limits. Geophysical and geotechnical investigation of the subsurface carried out in the study area for construction purposes revealed that the foundation of a heavy structure should be targeted at around 20 m into the subsurface.

VALIDATION EVALUATION OF THE METHOD OF QUANTITATIVE DETERMINATION OF α(1,2)-L-RHAMNO-α(1,4)-D-GALACTOPYRANOSYLURONANE ACORUS CALAMUS L. IN DOSAGE FORM

Introduction. The object of increased attention of researchers is calamus (Acorus calamus L.), for the components of which a wide range of pharma-cological activities have been identified – immunomodulatory, anti-inflammatory, analgesic, antioxidant, neuroprotective, hypolipidemic, antitumor. Ac-cording to previous studies, it was found that α(1,2)-L-rhamno-α(1,4)-D-galactopyranosyluronan, isolated from the rhizomes of Acorus calamus L., has antimetastatic, antiblastoma, and immunomodulatory properties. The substance can also reduce the toxic effect on the hematopoietic system and in-crease the effectiveness of chemotherapy. Based on it, a finished dosage form was obtained - a solution for intravenous administration of 10 mg/ml, which requires the development of valid quality control methods for inclusion in the draft regulatory document on the quality and registration of a new drug. The aim of the study was to determine the metrological characteristics of the chromatographic technique for the quantitative determination of α(1,2)-L-rhamno-α(1,4)-D-galactopyranosyluronan in the finished dosage form. Material and methods. The object of the study was the finished dosage form - a solution for intravenous administration of α(1,2)-L-rhamno-α(1,4)-D-galactopyranosyluronan Acorus calamus L. 10 mg/ml, produced on the basis of the educational establishment of the Technology Implementation Cen-ter of the Federal State Budgetary Educational Institution of Higher Education of the Siberian State Medical University of the Ministry of Health Russia. Quantitative determination was carried out using a Dionex Ultimate 3000 liquid chromatograph (Thermo, Germany) with a refractometric detector RI-101. Validation assessment was carried out according to the following indicators: linearity, accuracy, precision under repeatability conditions. Results. Linear regression analysis of the obtained results using the least squares method showed that the technique is linear in the concentration range of 80–120%. When determining the accuracy, the openability for concentrations of 80, 100 and 120% varied in the range of 99.68–101.96%. The values of the relative standard deviation did not exceed the permissible values when assessing precision 0.82–4.51%. Conclusions. The methodology is valid for the studied indicators and can be recommended for inclusion in the draft regulatory document on quality. The work was carried out within the framework of applied scientific research 720000F.99.1.BN62AB30000 within the framework of state assignment No. 056-00116-23-01.

An investigation of the effect of drawdown pressure on sand production in an Iranian oilfield using a hybrid numerical modeling approach

AbstractReservoir pressure reduction due to continuous production from oil and gas wells affects the sand production rate. An increase in drawdown pressure and/or a decrease in reservoir pressure increases the sand production rate. Since the problem of sand production is one of the main issues in the Asmari sandstone formation located in one of the oilfields in the southwest of Iran, therefore, in this research, the variations in the sand production rate due to the changes in the reservoir and drawdown pressures were investigated. So, for the first time, a hybrid numerical model of finite difference method (FDM)—discrete element method (DEM)—finite element method (FEM)—computational fluid dynamics (CFD) was developed. This numerical model investigated the increase in the sand production rate due to variations in reservoir pressure with a constant bottom-hole flowing pressure. Then, by performing an extensive sensitivity analysis on different values of reservoir pressure and drawdown pressure, the changes in the sanding rate, the critical drawdown pressure, and the safe drawdown line were determined. The results showed that, if the production flow rate of the well is constant, increasing the drawdown pressure can change the sand production rate only to a certain extent, and more than that, will be produced at a constant rate. Also, adjusting the drawdown pressure within a safe range does not necessarily keep the sand production rate constant at a permissible value for a long time, while by keeping the bottom hole flowing pressure constant within an acceptable range, the sand production rate can be controlled for a longer period.

Methodological aspects of assessing the level of risk resistance of retail trade enterprises

The article aims to improve the scientific and methodological approach to assessing retail enterprises' risk tolerance levels. The research process used the following methods: analysis, synthesis, structuring, systematization, graphic modeling, multidimensional analysis, and integral assessment. The article describes the main features of the modern external environment. Risk management is developing forward-looking thinking and forming readiness for risky situations. The essence of the "risk resistance" concept is revealed, and the main concepts that define it are characterized. A three-dimensional graphic model has been developed, and a methodological toolkit for assessing the level of risk tolerance of retail trade enterprises has been substantiated. An economic-mathematical model is proposed to estimate the probability of achieving a retail enterprise's target level of risk tolerance. A system of system-forming factors that influence the provision of the retail trade enterprise's target level of risk resistance has been formed. The scientific-methodical approach to assessing the level of risk resistance of a retail trade enterprise has been improved, considering the ability to resist external risks and the level of internal risks. It allows the formation of a system of management decisions to ensure a timely response to a wide range of resource and time constraints risks while contributing to achieving target indicators of activity retail trade enterprises. The graphic model of the values of the concepts of risk resistance of a retail trade company, developed based on the results of the study, focuses attention on the dynamics of the concept over time and creates an opportunity to ensure the control of the actual values of the concepts of risk resistance and determine their compliance with permissible, nominal, and critical values. Further research is planned to be devoted to conducting studies of current practices of external and internal risk management in Kharkiv's retail trade enterprises. Keywords: risk, risk resistance, level, risk-generating factors, concepts, integral assessment, integral indicator.

The elemental profile of ciders made from different varieties of apples

Macro- and microelements are vital components of the nutrient profile of apples and apple juice. Although the mineral composition of apple juices has been well studied, there is a lack of research into the elemental profile of ciders. We aimed to determine the concentrations of macro- and microelements in various samples of ciders. 
 We studied 25 experimental ciders from apple juice of direct extraction (fresh must) and 4 commercial ciders purchased from a retailer in Krasnodar. Mass concentrations of metal cations were determined by high-performance capillary electrophoresis, atomic absorption spectrometry with electrothermal atomization, and atomic emission spectrometry with inductively coupled plasma.
 The concentrations of macroelements in the ciders from fresh must depending on the variety varied significantly in the following ranges (mg/L): 696–1920 for potassium; 6.7–26.8 for sodium; 4.3–35.5 for calcium; and 10.2–36.8 for magnesium. The commercial ciders had significantly lower concentrations of macroelements. The content of iron ranged from 0.86 to 2.26 mg/L. Among microelements, copper cations were detected in the range from 31.0 to 375 μg/L. The concentrations of toxic elements did not exceed the maximum permissible values in any of the samples, including the commercial ones. Finally, ranges of variation were established in the concentrations of macro- and microelements depending on the varietal characteristics of apples.
 The pomological varieties of apples used in the study were grown under the same agrotechnical conditions. Therefore, the differences revealed in the elemental profile of the ciders were assumingly due to the genetic characteristics of the respective variety.

Assessment of non-carcinogenic and carcinogenic risks to the population living in the area affected bythe pulp and cardboard mill

The article deals with the health of population living in the area affected by the pulp and cardboard mill. The aim is to assess non-carcinogenic and carcinogenic risks to the Selenginsk population caused by emissions from Selenginsk pulp and cardboard mill. The article examines the dynamics of average annual concentrations of pollutants in the air of the urban settlement. The results of calculations of inhalation risks are presented. The non-carcinogenic risk values exceeded the permissible values for all pollutants. Fine particles PM2,5 and ozone O3 exceeded the norms 22 and 15 times respectively for the period of five years. The calculation of the carcinogenic risk level showed that there are additional cases of neoplasms in the population caused by benz(a)pyrene in the air, and the carcinogenic risk level is unacceptable. Emergency health measures are required to reduce it.

Analysis of the results of combined optimized YAG-laser trabeculostomy technology in the treatment of primary open-angle glaucoma

Two groups of patients were included in the study: the control group (prospectively) was 65 patients (65 eyes) with POAG I–II st. before and after SLT, and the main group (prospectively) was 60 patients (60 eyes) with POAG I-II st. before and after optimized YAG-laser trabeculostomy technology. Using OCT of the anterior segment of the eye the collector channel were localized relative to the Schlemm’s canal. After surgery, monitoring was performed after one day, one month, 3, 6, 12, 24 months. After optimized YAG-laser trabeculostomy, a pronounced hypotensive effect was observed as early as the first day after surgery and was 30 %, whereas with SLT the maximum hypotensive effect was observed 1 month after surgery (21.5 %). After optimized YAG-laser trabeculostomy, the hypotensive effect was maintained at 30.1 % and was 26.2 % of the initial level 2 years later. Combining optimized YAG-laser trabeculostomy technology in comparison with SLT offers faster IOP reduction to individual values, a more pronounced and sustained hypotensive effect (30 %), and allows more precise surgery in the projection of collector tubules using permissible laser energy values.

The concept of using wind turbine propellers in the construction of acoustic screens as an example of a circular economy model

This paper aims to conceptualise the construction of noise barrier panels from components recovered from used wind turbine propellers. At present, they are mainly waste, but many ideas for their reuse are emerging. Based on previously conducted material tests, the strength of the panels was calculated in accordance with EN 14388. The finite element method and the ANSYS space-claim programme were used to analyse the strength and generate a 3D numerical model of the cracked wind turbine propeller panels. The permissible values given in the standard were compared with those obtained for the deflection of the component.

Comparison of the Work of Wastewater Treatment Plant “Ravda” in Summer and Winter Influenced by the Seasonal Mass Tourism Industry and COVID-19

Mass tourism puts enormous pressure on wastewater treatment plants due to its expansive growth during the summer months. To adapt to the fluctuations, the Ravda wastewater treatment plant (WWTP) uses innovative methods and technologies, allowing for “shrinking” and “expanding” of the facilities according to the season. This has been built in stages over the years, with two separate biological treatment lines adapting to different numbers of tourists and to the quantity of influent wastewater. The aim of this study is to make a comparative assessment of the work of WWTP Ravda in the summer and winter seasons and its effectiveness, as well as to compare them. In addition, it examines the years of the COVID-19 pandemic, when a much higher consumption of water per person was noted. Data were analyzed for the period of 2018–2022 inclusive, comparing influent and effluent BOD5 and COD in the summer and winter. Nitrogen and phosphorus removal efficiencies were also tracked. The study shows that municipal wastewater treatment is effective, but much higher values, close to the maximum permissible discharge values, are observed during the tourist season. With the continued growth of the tourism sector, the Ravda wastewater treatment plant would not be able to cope with the discharge standards set by the Ministry of Environment and Water, so measures need to be taken promptly.

Autotransporto triukšmo sklaidos numatomos statybos sklype modeliavimas

The article analyses the options for the layout of the planned residential building on the site, assessing the acoustic level of the environment. The analysis is important because the area is next to a busy street and a railway line, and the building is intended to be used for the permanent residence of people with special needs. In the initial version of the model, the location of the building on the site is chosen 7 m from the street boundary. Due to the results of the model analysis – the sound pressure to the facades in 41% of the area exceeds the permissible values, to the roof – 30 %, to the ground – 24 % – the position of the building was adjusted, placing it another 9 m away from the street, and vegetation was inserted, a ditch filled with peat 0.9 m of depth in the ground is recommended at the south-western border of the plot.

Study on the Strength of the Brake Pad of a Freight Wagon under Uneven Loading in Operation.

The paper highlights the results of determining the strength of the brake pad of a freight wagon under uneven loading in operation. The main reasons for the uneven loading on the pad have been found. A mathematical tool for determining the strength of the pad unevenly loaded has been proposed. In the study, the pad is considered to be a rod system loaded with concentrated forces and bending moments. Sensors have been used in order to detect the load state of the brake pads. These sensors have been defined in the simulation software, and they have been placed on the working surface of the pad in the area of its interaction with the wheel. The operation of these sensors was simulated in the simulation software package. The results of the calculation have shown that the stresses in the pad are about 21.1 MPa; thus, they exceed the permissible values by 29%. Therefore, considering the uneven loading of the pad in operation, the strength of the pad is not ensured. To test the obtained results, the strength of the pad was determined using the finite element method. The Coulomb criterion was used for the calculation. It was found that the maximum stresses in the pad were about 19 MPa. These stresses were 21% higher than permissible values and occurred in the back of the pad. The study has proven that the uneven loading on the brake pad in operation can cause their destruction during braking. This may also cause traffic accidents with freight trains during their movement. The results of this study will contribute to the theoretical developments and recommendations aimed at improving the brake system of a freight wagon and rail traffic safety. It is considered that the tensometric sensors will be applied in future experimental tests for comparison and verification of the achieved results from the simulation computations.

Behavior of spin-0 scalar particles in Eddington-inspired Born–Infeld gravity global monopole with harmonic oscillator potential

In this paper, we investigate the behavior of a scalar bosonic field within the backdrop of Eddington-inspired Born–Infeld gravity with a global monopole configuration. Additionally, we consider the presence of both scalar and vector potentials. To introduce the scalar potential, we perform a transformation on the mass term, replacing [Formula: see text] with [Formula: see text]. For the vector potential, we apply a minimal coupling scheme, transforming [Formula: see text] within the relativistic Klein–Gordon equation. We opt for a harmonic oscillator scenario where the scalar and vector potentials are equal, i.e. [Formula: see text]. Through this setup, we analytically solve the wave equation using the confluent Heun equation form. Subsequently, we delve into the quantum system in the absence of any potential, determining the permissible values for bound-state relativistic energy levels and the scalar field’s wave function. Our analysis reveals that the energy levels and wave function are influenced by various parameters present in the eigenvalue expression.

Geotechnical Properties of Sand-Asphalt for Use in Road Base Layer Instead of Conventional Materials

The study of the geotechnical properties of sand-asphalt for use in road base layer instead of conventional materials, for low to moderate traffic volume, is based on standardized laboratory tests. Sand samples were taken from Kayar, Darou Alpha and Keur Morry (Thies region, Senegal). Identification tests (particle size distribution and sand equivalent) made it possible to select Kayar and Darou Alpha sands which have respective sand equivalent (ES) values of 92 % and 62 %. These values are higher than the minimum required (40 %), for sand-asphalt, with different 35/50 bitumen dosages. The results of the Hubbard-Field test carried out showed that Darou Alpha sands are suitable, with an optimum dosage of 7 % bitumen : the stability at 18 °C, at dry conditions, is 2 732 kg and is greater than the minimum required value of 2 300 kg; the immersion/compression ratio is 85 % and is greater than the minimum required limit of 75 %; water absorption reaches 5.4 % and remains below the maximum required limit of 7 %; the volumetric swelling is 2.6 % and is below the maximum required limit of 5 %. The compactness is 84 % and is acceptable because it exceeds the minimum required limit of 80 %. The sizing carried out with the Alizé©3 software gives deformation values lower than the permissible values. The pavement structure that is placed on a PF3 type platform is therefore correctly sized to support a traffic of 150 heavy vehicles per day for a service life of 15 years. This roadway structure, which is devoid of a foundation layer, includes a 23 cm thick sand-asphalt base layer on which rests a 5 cm thick asphalt concrete. Keywords: sand-asphalt, Hubbard-Field test, Kayar, Darou Alpha, Keur Morry.

New Method for Precise Measurement of Clamping Plate Deformations on Forming Presses

The deformation of press bolster plates under load can significantly impact the quality of manufactured workpieces. Consequently, press manufacturers are usually obliged to provide the metric proof of the permissible deformation values during the press commissioning process. Unfortunately, the existing measurement methods for determining bolster plate deformations present flaws in the measurement accuracy, the application flexibility, the metrological effort, and other aspects. These issues have been addressed through the development of a new measurement method using multiple inclination profiles on the surface of the measured object. Based on the difference in the inclination between the unloaded and loaded states, the method approximates the inclination surface and calculates the deformation of the measured object through integration. The measurement method was first used for commissioning tests of forming presses. A comparison with the results obtained with a measurement frame equipped with high-resolution measurement probes demonstrates an accuracy of the new method of less than 20 µm.

Hazardous arsenite removal from water by calcined Fe-hydrotalcite

This study is aimed at using calcined Fe-Hydrotalcite (CFeHT) in removing arsenite (As(III)) from water. The arsenic concentration of solutions containing 1000 μg/L As(III) in adsorption studies was reduced below the permissible value (10 μg/L) with 2 g/L CFeHT for As(III). The effect of initial pH on adsorption was limited, and arsenic adsorption occurred relatively quickly under the pseudo-second-order kinetic model. In equilibrium isotherm studies, experimental data were consistent with Langmuir isotherm. Also, we clarified that CFeHT can be reused with proper treatments such as desorption and revivification. Competitive ions such as B(OH)42 did not significantly affect arsenic adsorption. It was determined that the adsorption process with CFeHT has high selectivity towards arsenic and is not affected by high amounts of borate anions in water. As a result of the regeneration tests, the arsenic removal efficiency from the solution containing As(III) was 62% at the end of the fourth cycle. This study reveals the great potential of CFeHT in removing arsenite contamination from groundwater originating from mines, especially from boron mines.

Evaluation of the physicochemical and bacteriological quality of groundwater in the Nihit rural commune of the Moroccan Anti-Atlas

Our study evaluated the physico-chemical and bacteriological quality of water wells and boreholes in the rural commune of Nihit in the Moroccan Anti Atlas. In this study, we assessed the physico-chemical qualities of the water such as pH, temperature, conductivity, turbidity, nitrate, nitrite, sulfate, mineral elements, and heavy metals. We also studied the bacteriological quality of the water in terms of microbial germs represented by Total Coliforms, Fecal Coliforms, Escherichia coli (E. coli), Intestinal Enterococci, and sulfito-reducing Clostridium.Apart from two points located upstream of the Douars, nitrate concentrations range from 60 to 290 mg.L-1, well above the permissible value according to the World Health Organization (50 mg.L-1). At some points, values reach concentrations of 4.1.103 CFU/100 mL, 1.9.102 CFU/100 mL, 60 CFU/100 mL, 1.8.103 CFU/100 mL, and 90 CFU/100 mL, respectively for total coliforms, fecal coliforms, Escherichia, intestinal enterococci and sulfito-reducing Clostridium. The presence of Total Coliforms, Fecal Coliforms, and E. coli in the water tested is an indicator of contamination by human or animal fecal matter, which may come from conventional septic tanks, untreated wastewater discharges, animal manure leaching, or runoff. On the other hand, the values of the other physicochemical parameters tested remain compliant with potable water standards.

Calculation of slope stability against erosion deformations

The paper considers the problems of erosion deformations occurrence for non-flooded slopes of railroad earth bed, where the main causes of scour are atmospheric precipitation or longitudinal currents along the bottom of the slope. The local stability of slopes is calculated taking into account the estimated velocity of water flow on the slope when water moves along the slope. Climatic conditions and soil characteristics on the Bukhara-Misken line were used for calculations. If local stability of slopes is not ensured, measures for slope stabilization are appointed. The technology of reinforcement of embankment slopes with geosynthetic materials with backfilling with a layer of vegetative soil and grass sowing is considered. The stability coefficient on the displacement surface is calculated taking into account the application of the selected reinforcement design. The stability coefficient on the displacement surface taking into account geomat reinforcement increased 3 times and exceeded the permissible minimum value.