Engineering Journal of Satbayev University

Formation conditions, resource potential, and utilization prospects of cretaceous thermal groundwater in the Zharkent artesian basin

2026-09-14T07:36:35+00:00

This study examines the formation conditions and resource potential of the Cretaceous thermal aquifer system of the Zharkent Artesian Basin, located in the eastern part of the Ili intermontane basin within the Panfilov District of the Zhetysu Region, Kazakhstan. The study is based on drilling and testing data from 18 deep wells completed between 1957 and 2016, supplemented by industrial hydrogeological reports and published results from previous investigations. The methods included structural-geological analysis, hydrodynamic delineation of the groundwater recharge area, and a groundwater-balance approach in which subsurface inflow was calculated using Darcy’s law. The Upper Cretaceous aquifer occurs at depths of 1680-3702 m and, within the most prospective right-bank sector of the basin, at 2670-3702 m. The water-bearing sequence is 54-130 m thick. Wellhead water temperatures range from 74 to 103°C, free-flow discharge rates from 22 to 75 L/s, and excess wellhead pressures from 1.4 to 53.5 kgf/cm². The groundwater has low mineralization of 0.26-0.90 g/dm³, is alkaline, and is predominantly of the Na–Cl–HCO₃ hydrochemical type, with elevated fluoride and dissolved silica concentrations. The recharge balance of the Cretaceous aquifer comprises four principal components: infiltration of surface runoff, 2.05 m³/s (43.6%); infiltration of atmospheric precipitation, 0.107 m³/s (2.3%); subsurface inflow from fractured Paleozoic rocks, 0.534 m³/s (11.3%); and inflow along tectonic fault zones, 0.635 m³/s (13.5%). Total recharge within the territory of Kazakhstan is estimated at 3.326 m³/s. When transboundary groundwater inflow from the territory of China, estimated at 1.377 m³/s, is included, total recharge reaches 4.703 m³/s, equivalent to 406.3×10³ m³/day. The approved exploitable groundwater reserves of the Zharkunak geothermal field, amounting to 12960 m³/day under categories B+C₁, represent only about 3.2% of the estimated natural groundwater resources. This ratio indicates substantial remaining potential for further development of the basin. The thermal-energy potential of the approved reserves is estimated at 3524.1 GJ/day, corresponding to an average thermal capacity of 40.8 MW, an annual thermal-energy output of 357.6×10³ MWh, and an equivalent replacement of 43.9×10³ tonnes of standard fuel per year. Potential pathways for cascading utilization of the geothermal resource are proposed, and two prospective development projects for the Zharkent Basin are considered.

Performance evaluation of blasthole drilling equipment in a limestone quarry using overall equipment effectiveness

2026-11-02T14:13:41+00:00

Blasthole drilling is a key operation in hard-rock quarrying, yet its operational effectiveness in African cement-production contexts remains insufficiently quantified. This study applies the Overall Equipment Effectiveness (OEE) framework to evaluate three Epiroc DM30 XC rotary blasthole drills at the Dangote Cement Plc limestone quarry in Obajana, Kogi State, Nigeria, and identify the principal sources of productivity loss. Field data were collected during fifteen day-shift observation sessions, comprising five sessions per machine over a three-month period. Scheduled operating time, planned and unplanned downtime, total holes drilled, actual cycle time, and hole quality were recorded using operator logbooks, maintenance records, and direct field observation. OEE was calculated from availability, performance efficiency, and quality rate, and daily values were averaged for each machine. DM30 No.1 achieved the highest mean OEE of 66.73%, with availability of 81.82% and performance efficiency of 81.56%, reaching a daily OEE of 84.83%. DM30 No.2 recorded a mean OEE of 58.27%, with availability of 83.27% and performance efficiency of 69.97%. Its maximum daily OEE of 87.27% indicated substantial variation between shifts. DM30 No.3 had the lowest mean OEE of 48.31%, with availability of 73.27% and performance efficiency of 65.93%; unplanned downtime exceeded 300 minutes in one observed shift. All recorded holes met the specified acceptance criteria, yielding a quality rate of 100% for each machine. Availability and performance losses therefore accounted for the observed reductions in OEE, with their relative contributions varying between machines. The findings support prioritising maintenance planning, operator performance monitoring, and standardised drilling procedures. These measures could improve equipment effectiveness and the reliability of limestone supply, although their benefits require verification through longer-term monitoring.

Hydrogeological assessment and temperature heterogeneity of the Karadala geothermal groundwater field on the left bank of the Ili River

2026-09-16T15:20:09+00:00

The Karadala groundwater field in southeastern Kazakhstan is an important source of fresh confined groundwater and a potential low-temperature geothermal resource. This study aimed to characterize its hydrogeological setting and temperature heterogeneity within a defined study area on the left bank of the Ili River using archival records from 1968-1971 and hydrogeological survey materials from 2022-2024. A dataset comprising 15 wells located within the study-area polygon was analysed using descriptive statistics, Pearson and Spearman correlation analyses, and ordinary least-squares regression to assess the relationship between reported well depth and groundwater temperature. Well depths ranged from 420 to 663.5 m, while groundwater temperatures ranged from 22.0 to 42.4°C. A moderate positive relationship was observed between depth and temperature (Pearson’s r = 0.554, p = 0.032; Spearman’s ρ = 0.666, p = 0.007; R² = 0.307), together with pronounced temperature differences among wells of similar depths. The results indicate that well depth explains only part of the observed temperature variability and that the potential effects of localized groundwater flow, aquifer mixing, screened intervals, and tectonic controls require further investigation through standardized monitoring, static temperature logging, hydrochemical analysis, and environmental-tracer techniques.

Modern methods for investigating hot cracking susceptibility in metallic materials

2026-01-28T11:57:17+00:00

The development of modern science and technology has shown that ensuring high product quality depends not only on the operational characteristics of materials, but also on their technological properties. In the production of aluminum alloys, ingots are most commonly used as the initial material for wrought alloys, while shaped castings are used for casting alloys. One of the most widespread defects occurring during the production of castings and ingots is hot cracking, which is the tendency of a material to form crystallization cracks during solidification. The problem of hot cracking is particularly relevant in the development and production of new high-strength and heat-resistant aluminum alloys, since the ranges of their chemical compositions often coincide with regions of increased hot cracking susceptibility. A pronounced tendency of alloys to hot cracking during casting and fusion welding significantly complicates, and in many cases makes practically impossible, their introduction into mass production despite their valuable service properties. As a rule, reducing hot cracking susceptibility in the development of new alloys is achieved through lengthy and labor-intensive experimental studies. This paper considers a method for evaluating the hot cracking susceptibility of aluminum alloys using the pencil test. The physical nature of the hot cracking phenomenon is described, the principle of the method is presented, and the testing procedure and analysis of the results are outlined. In addition, a schematic representation of the hot cracking test according to the pencil test method and a list of references are provided.

TiZrNbTa-based bio-high entropy alloys for biomedical applications: a comprehensive review

2026-07-08T07:26:04+00:00

The increasing demand for advanced biomedical implants has driven the development of novel metallic biomaterials with improved mechanical compatibility, corrosion resistance, and biocompatibility. Conventional implant materials such as Ti–6Al–4V, Co–Cr–Mo alloys, and stainless steel, often suffer from limitations including stress shielding, ion release, and long-term biological concerns. Among emerging biomaterials, TiZrNbTa-based bio-high entropy alloys (Bio-HEAs) have emerged as promising candidates due to their composition of biocompatible elements and their unique combination of high strength, low elastic modulus, excellent corrosion resistance, and favorable biocompatibility. This review summarizes recent developments in TiZrNbTa-based Bio-HEAs, with particular emphasis on microstructural evaluation, new elemental addition strategies, mechanical properties, corrosion behaviour, and biocompatibility. Reported studies demonstrated that TiZrNbTa-based Bio-HEAs exhibit stable body-centered cubic (BCC) solid-solution structures, although phase stability and microstructural characteristics can be tailored through compositional modifications, thermomechanical treatments, and advanced manufacturing processes. Depending on composition and processing conditions, TiZrNbTa-based Bio-HEAs exhibits the elastic modulus ranging from 57 to 135 GPa and yield strengths exceeding 1000 MPa providing a favorable balance between mechanical strength and compatibility with human bone. Furthermore, the formation of stable passive oxide films rich in TiO₂, ZrO₂, Nb₂O₅, and Ta₂O₅ contributes to excellent corrosion resistance in physiological environments. Biocompatibility studies have demonstrated favorable biological responses, highlighting the potential of TiZrNbTa-based Bio-HEAs for orthopedic and dental implant applications. Finally, current challenges and future research directions for the development of next-generation biomedical implants are discussed.

Microstructure, internal friction and impact-induced acoustic response of newly developed alloyed steels

2026-11-01T05:50:05+00:00

This study evaluates the relationships among mechanical energy dissipation, elastic stiffness, electrical resistivity, microstructural heterogeneity and impact-induced sound radiation in three newly developed alloyed steels (XSM-1, XSM-2 and XSM-3). Standard carbon steels St.10, St.20 and St.45 were used as reference materials. Plate specimens (50×50×5 mm) underwent steel-ball impact testing, with transient oscillograms captured in a 2 ms observation window; torsional oscillation measurements, sound-level measurements and metallographic observations provided complementary evidence. XSM-1 exhibited the greatest tabulated internal friction (21.22×10^–4) and the lowest A-weighted sound level (72 dBA), compared with 9.11-10.565×10^–4 and 84-89 dBA for the reference steels. XSM-2 reached 77 dBA and XSM-3 87 dBA, despite both having relatively high internal friction. The descriptive Pearson association between internal friction and sound level across the six materials was approximately −0.70, whereas elastic modulus values did not show a clear monotonic pattern. Micrographs available for XSM-3 indicate structural heterogeneity but do not provide definitive phase identification. The results suggest that intrinsic material damping is important but insufficient on its own to predict impact noise; modal response, microstructure and testing configuration should be considered jointly. The study identifies XSM-1 as the leading candidate within this limited comparative dataset and specifies the measurements needed for independent validation.