Process Technology Research Articles

Transformação sustentável

The objective of the research was to apply composting techniques and social technology to treat food waste in a low -income condominium in southern Brazil, with the joint participation of university researchers and residents. The purpose was not only to reduce the environmental impact caused by waste, but also generate organic compounds of environmental and agronomic value. The project started with an observational visit to the condominium to identify appropriate spaces for the execution of the work. Then the researchers promoted the project through posters and direct conversations with the residents. After this interaction, training workshops were held for participating residents, totaling 40 families and 122 people. The workshops addressed topics such as the impacts of food waste, segregation at source, the composting process and social technology. Educational materials were distributed to assist in the learning process, and visual resources, such as workshops and educational videos, were used. Finally, the composting process was implemented. Social technology played a significant role throughout the process. During workshops and interactions with residents, participants became active learning agents, sharing traditional knowledge and integrating them with scientific knowledge. Educational materials have represented an important tool for social technology, providing information in an accessible and motivational way. The active participation of researchers and residents was also a positive aspect of this investigation, as it strengthened the condominium community, created social bonds and promoted awareness of environmental responsibility.

Development and verification of material models in modeling of wave strain hardening and additive synthesis processes

BACKGROUND: The creation of competitive machine parts capable of withstanding standard and increased operational loads is an urgent task in mechanical engineering. Developing additive synthesis technologies together with strengthening technologies make it possible to create such products with high load-bearing capacity. However, to improve the efficiency of these technologies, it is necessary to create theoretical models of the processes taking place. The article presents the results of the first stage of creating complex theoretical models of the combined 3DMP process and wave strain hardening (WSH) required for designing technological processes for manufacturing engine parts and brake systems of automotive equipment. . AIMS: Creation and assessment of the adequacy of material models used in finite element modeling of additive synthesis processes with subsequent hardening. MATERIALS AND METHODS: Theoretical models of the material were created in the ANSYS software package, which allows for multidisciplinary calculations. The experimental data required for preparing the models were obtained by testing tensile samples manufactured using standardized methods. The hardness of materials was studied using a KB 30S automatic hardness tester. The adequacy of additive synthesis modeling was assessed based on the distribution of temperature fields. The adequacy of material models for the VDU process was assessed based on the sizes of individual plastic indentations and the distribution diagrams of the depth and degree of hardening in the surface layer. RESULTS: Theoretical models of the following materials were developed: steel, stainless steel, bronze alloy, titanium alloy, aluminum alloy. The theoretical data obtained from the modeling results have a high level of significance. The studies were conducted for various thermal (in the range from +20ºС to +800ºС) and deformation modes. Graphical results of theoretical and experimental studies allow us to obtain a qualitative assessment of the processes under study with the required accuracy. CONCLUSIONS: As a result of the assessment of the adequacy of the developed models, it was established that the discrepancy between the empirical and theoretical data does not exceed 7.4%. The obtained models of materials are statistically significant and can be correctly applied in further studies.

Assessment of Safety Probability of Fastening Operations in Loading-unloading Work Process

One of the important strategic objectives in the target programs for economic and social development adopted by the Government of Georgia is to improve the coordination of all types of transport – sea, rail, road, air, and pipeline. The methods of organizing and managing the transport system at different levels greatly impact solving the problems faced by water transport. Therefore, research in the field of improving the organization and management of the transport hub (port), as an integral part of this system, plays an important role in increasing the traffic volume and service quality of all types of transport on the transport corridors of Georgia. Foreign and domestic experience shows that a large percentage of waiting times for cargo operations by ships and berths is mainly due to the lack of coordinated actions between the adjacent modes of transport and ports and the imperfection of the organization and management of loading and unloading processes in ports. In this regard, it is necessary to focus on identifying and eliminating "vegetables". First of all, this link of the transport system connects water and land transport routes. Transport communications have long been called the arteries of life. Without them, the economy's rise and the country's prosperity, even if it has huge natural resources, is impossible. Whoever controls the transportation system holds the levers of economic management, which means that he can decide the fate of the entire state. The development of transport communications of the global transport system puts new demands on the quality of functioning of the existing intermodal corridor through Georgia. In particular, the transport corridor created by the EU countries under the name ITC TRACECA creates new challenges for the existing transport system of Georgia to maintain the transit cargo flows between Europe and Asia in competition with the seaports of Georgia, Azerbaijan, and partly Ukraine and Russia. In this regard, all the main directions of improving the organization and management of the technological processes of seaports become relevant: (i) increasing the capacity of berths and transport complexes in the Black Sea ports of Georgia to the maximum limit by reducing costs; (ii) creating new methods for identifying capacity reserves, which will ensure the competitiveness of Georgian seaports in competition with these ports; (iii) speeding up the process of transit cargo transportation through seaports, as well as reducing the processing time of cargo going to export and import in Georgian ports. Keywords: Transport hub, organization of technological processes, ship unloading work.

Development of a Low-carbon Sintering Process Technology and Its Application to a Pilot-scale Sintering Testing

Development of a Low-carbon Sintering Process Technology and Its Application to a Pilot-scale Sintering Testing

Site-Specific Stochastic Rates and Energetics of Ag Nucleation on Highly Ordered Pyrolytic Graphite.

Nucleation is a fundamentally important step in electrochemical phase transition reactions, e.g., in electrodeposition, which is pertinent for emerging battery technology, nanoparticle synthesis, and many industrial processes. Surface defects have been suggested to enhance nucleation rates. However, directly quantifying the nucleation rates at specific surface sites is challenging due to the ensemble averaging effect in bulk measurements. Herein, we report the measurement of rates and energetics of electronucleation across the model surface of highly oriented pyrolytic graphite (HOPG). Specifically, scanning electrochemical cell microscopy (SECCM) is used to confine the nucleation spatially in the nanoscale cell, allowing one nucleation event to be measured at one time. The scanning capability further allows the mapping of Ag nucleation at the step edge vs basal plane. A stochastic model is developed to extract the nucleation rate and energetics from voltammetric experiments. We observed a ∼57 mV difference in the median nucleation overpotential between the step edge and basal plane, corresponding to a ∼12 kJ mol-1 difference in the nucleation energy barrier. The voltammetric method to measure the nucleation rate explored here can be extended to understand the heterogeneity of nucleation rates in other electrochemical nucleation systems, e.g., metal anode batteries.

Current state and emerging trends in advanced manufacturing: process technologies

Current state and emerging trends in advanced manufacturing: process technologies

Methods of Balancing Technological Systems of Multiproduct Production

The functioning of the machine-building industry has its specifics, particularly periodic changes in the range (size, configuration, and others) of manufactured products. In addition, it is essential to consider the need to reduce the time spent on the production of each unit. Almost continuous changes in technology, failures in the supply of raw materials, uncoordinated logistics, and many other factors often cause significant and unproductive costs, leading to an increase in the technological stage. The most promising direction to reduce the technological time of manufacturing products by multiproduct enterprises is to reduce the waiting time owing to the uniform distribution of each technological transition according to the state of the available workshop equipment (plant, production area, enterprise). This study proposes a novel model of technological systems that enables the adaptation of technological processes for part manufacturing and comprises data structures that define their technical capabilities. The proposed algorithm facilitates a reduction in downtime and an increase in equipment utilization factor. It is possible to optimize the technological processes that change the structure of each production operation to adapt to the existing technology. Testing this methodology demonstrated a significant increase of 8% in the process utilization rate of machinery.

Application of Digital Literacy Using Mapalus Techniques in Learning in North Sulawesi

Entering the era of the fourth world industrial revolution in this case information technology has become the basis of human life. In this era almost all life effects utilize digital, including in learning, one of which is digital literacy. Along with technological advances and the increasing individualism of society due to globalization, for this reason this study collaborates digital literacy and local culture, namely mapalus which means cooperation in learning in North Sulawesi. The purpose of the study is to determine the process of implementing digital literacy with the mapalus technique and to evaluate the effects of implementing digital literacy with the mapalus technique in learning. This research is a descriptive qualitative type of research. The data collection techniques used are observation, interviews and documentation. The results of the study show that the application of digital literacy in learning facilitates easy access for students to materials and assignments given by educators. This also increases students' interest in using technology in the learning process and by using the malapus technique which makes students work together and work together to complete the tasks given in learning.

In-House Training Modules on Learning Media to Improve Information and Communication Technology Competence in Elementary School Teachers

In-house training (IHT) programs effectively address educational challenges in schools through a thorough needs analysis. While IHT programs are frequently conducted, the primary focus should be on enhancing the quality of training to meet the specific needs of institutions, roles, and individuals involved. At SDN 98, a notable issue is the low utilization of technology in the learning process despite adequate multimedia facilities. Among 17 classroom teachers, fewer than 25% are proficient in using computers for instruction, and only one or two teachers regularly use laptops. The use of LCD projectors is also rare. This situation highlights the urgent need to improve teachers' information and communication technology (ICT) skills. Consequently, this Study aims to enhance the ICT competencies of SDN 98 teachers through targeted training and the development of IHT modules. The research employs a research and development (R&D) method that includes eight stages: initial research, planning, product design, validation, revision, limited trials, and field trials. The developed IHT module received excellent evaluations, with an average score of 4.49 from respondents and 4.56 from instructors, indicating its practicality and effectiveness in enhancing teachers' ICT competencies.

OVERVIEW OF HEALTHCARE INNOVATION AND ENTREPRENEURSHIP

The healthcare system is under constant pressure from a growing and aging population, escalating healthcare costs, limited resources and increasing demand. Achieving the triple aim of healthcare – improving care, improving health and reducing costs – requires innovation. According to the World Health Organization (WHO), health innovation is the development of new or improved health policies, systems, products and technologies, services and delivery methods that improve people’s health, with a particular focus on the needs of vulnerable populations. Health innovations have both technological (innovative products, services or processes) and non-technological (organizational, policy, educational and social innovations) dimensions and play a critical role in improving the productivity, effi ciency, reliability, sustainability, safety and cost-eff ectiveness of health care. This article is the fi rst in a series of publications on innovation and entrepreneurship in health care. The paper examines the main types and categories of innovation and entrepreneurship, analyzes current innovation trends and directions in healthcare, factors that infl uence the adoption of innovative technologies in medical practice, and the characteristics of a human- centered approach to design thinking in healthcare. The article also discusses the concept of value- based healthcare, which focuses on providing the best possible care to achieve the best possible outcomes for each patient, using available resources effi ciently, and how innovation can improve the cost, quality, and access to healthcare.

Navigating Resistance to Technological Change in Organizations: A Holistic Approach

Organizational change driven by technological advancements presents both opportunities and challenges for modern enterprises. A key obstacle is a resistance to adopting new technologies, which can manifest through scepticism, fear of job displacement, perceived loss of control, and concerns about competence. This resistance poses significant barriers to the successful implementation and integration of technological innovations, leading to delays, inefficiencies, and missed opportunities for organisational growth and competitiveness. This research proposes a holistic approach to address the complex challenge of resistance to technological change. Drawing on theoretical frameworks such as the Adaptive Cycle of Resilience (ACoR) model, Maslow's Motivation Theory, and Keidel's organisational model, as well as practical strategies, the study examines the interplay between individuals, different management, organisational and societal needs in the context of technological transformation. The research explores the dynamic and uncertain nature of technological change, identifying the specific stages within the ACoR model where resistance is most likely to occur and the implications for effective management. It also investigates the role of various management styles in addressing resistance and uncovering the skills and knowledge individuals and teams require to navigate this challenge successfully. Furthermore, the paper delves into the diverse stakeholders involved in the technological change process, analysing their needs and concerns and offering strategies to balance these competing interests. The importance of information systems in facilitating organizational change and their influence on the change process and outcomes is also examined. By synthesising these insights, the study presents a comprehensive framework for organisations to foster innovation, inclusivity, and social responsibility in the face of resistance to technological change. The findings offer valuable guidance for practitioners and scholars seeking to enable successful technological transformations and promote positive outcomes for all stakeholders.

Innovation and sustainability in technology parks: the transformation of Itec Park UFN through the PDCA cycle

This study examines the transformative role of the PDCA (Plan-Do-Check-Act) cycle as a strategic framework for managing science and technology parks, using Itec Park UFN as a case study. By implementing PDCA-based tools, this research seeks to streamline the operational processes of technology parks through structured planning, execution, monitoring, and continuous improvement. The approach aligns closely with the Sustainable Development Goals, notably SDG 9: Industry, Innovation, and Infrastructure. Employing an action research methodology that integrates literature review, tool development, and pilot implementation, the study emphasizes strategic management, innovation promotion, and knowledge transfer as core aspects. Findings reveal that the PDCA cycle enhances the park’s capacity to adapt to market shifts, supporting resilience and fostering a culture of sustainable innovation. The structured use of PDCA not only improves operational efficiency but also promotes stronger partnerships between academia, industry, and government. This systematic management approach establishes a replicable model that can be adapted by other science and technology parks, providing practical insights into the creation of innovation ecosystems that catalyze regional economic development and empower startup growth. Ultimately, the research contributes to the field by demonstrating how structured, goal-oriented methodologies can drive sustainable technological and economic advancement.

CONTRIBUTION TO IMPROVING OF MACHINE PARTS MECHANICAL PROPERTIES BY THERMOMECHANICAL HARDENING

Current industrial production is characterized by requirements for improving the physical and mechanical properties of the used material. This causes a workload creating a rather complex load on all types of machines and mechanisms during operation. The design of such objects is currently based on a wide range of computational and experimental methods that allow modelling their state and behaviour even in the case of complicated non-stationary loading conditions. In this paper, the authors focus on the statistical evaluation of selected manufacturing operations related to mechanical and thermomechanical processing of products [Kuric 2011]. For example, in the case of long pipe billets with a thickness coefficient of 2-4, practically the only way of their production in the metallurgical cycle is cross-roll piercing followed by reduction. This process has high productivity but at the same time certain disadvantages. These disadvantages limit the efficiency and the range of use of the pipe blanks obtained by piercing, which leads to a consequent shortening of the machine production cycle. The presented approaches allow changing the structure of technological processes of production of axisymmetric metal products, by modifying the thermomechanical processing at the beginning of the production cycle.

ABOUT THE GUARANTEED INTRADEPARTMENTAL RESERVE IN THE CONTEXT OF INTRALOGISTICS

In general, the current paper implies the conclusion that the determination of the impact of randomly occurring pauses in the work of the production unit with continuous technological process depends on the created intradepartmental guaranteed reserve.

OBTAINING ASEPTIC CULTURE IN VITRO OF RHODIOLA SEMENOWII L. FROM VARIOUS TYPES OF EXPLANTS

In vitro cultivation of callus cells allows for the stable production of secondary metabolites, being an alternative to the use of medicinal plant biomass from natural populations. Standardization of cultivation protocols and technological processes for the synthesis of secondary metabolites in vitro conditions determines significant interest in the use of tissue culture methods (PTC – Plant Tissue Culture). The aim of the study was to obtain an aseptic culture of Rhodiola semenowii in vitro from various types of explants, as well as the effect of the hormonal composition of the nutrient medium on the induction of callusogenesis in the culture of isolated organs of R. semenowii. As a result of the research, the optimal mode of obtaining R. semenovii aseptic cultures from various explants was determined. It has been shown that the use of 70% EtOH in combination with 0.01% HgCl2 or 20% NaClO makes it possible to obtain aseptic cultures from any type of R. semenovii explants. It has been established that the type of explant is R. semenovii influenced both the frequency of callus formation and the beginning of its formation. The least optimal types of R. semenovii explants are stem and rhizome segments, the frequency of callusogenesis varied from 5.8% to 75.6%. The induction of callusogenesis also depended on the hormonal composition of the nutrient medium: the highest percentage of callus formation in all types of explants was on media containing 0.5mg L−1 thidiazuron (TDZ) + 1.0 mg L−1 1-naphthaleneacetic acid (NAA) and 0.5mg L−12,4D + 2.0 mg L−1 6-Benzylaminopurine (BAP).

IMPROVEMENT OF THE HOMOGENIZER HEAD DESIGN

Summary. An analysis of the equipment used for the homogenization of milk raw materials was carried out. Technologies for obtaining homogenized milk are considered. Disadvantages of existing technological processes have been identified. The areas of improvement of homogenization processes are defined and the need for the development of equipment for their implementation is substantiated. The research methods of the homogenization process are substantiated, a description of the studied raw materials is given, and the design of the homogenizer head is proposed. The influence of the geometric parameters of the modernized homogenizer head on the efficiency of the homogenization process was determined, and the optimal parameters were determined experimentally. As a result of the conducted research, it can be concluded that the homogenization process is very important for the production of pharmaceutical emulsions. The calculation and modeling of the homogenizing head of the valve homogenizer was carried out. In order to carry out two-stage homogenization, it was proposed to modernize the homogenizing head. the previous design is inferior to the modernized one in terms of homogenization of food liquids.

Structural, Mechanical, and Optical Properties of Laminate-Type Thin Film SWCNT/SiOxNy Composites

The development of new encapsulating coatings for flexible solar cells (SCs) can help address the complex problem of the short lifespan of these devices, as well as optimize the technological process of their production. In this study, new laminate-type protective composite coatings were prepared using a silicon oxynitride thin-film matrix obtained by curing the pre-ceramic polymer perhydropolysilazane (PHPS) through two low-temperature methods: (i) thermal annealing at 180 °C and (ii) exposure to UV radiation at wavelengths of 185 and 254 nm. Single-walled carbon nanotubes (SWCNTs) were used as fillers via dry transfer, facilitating their horizontal orientation within the matrix. The optical, adhesive, and structural properties of the matrix films and SiOxNy/SWCNT composite coatings, along with their long-term stability, were studied using Fourier transform infrared spectroscopy (FTIR), UV-Vis spectroscopy, HR-SEM, spectral ellipsometry, and a progressive-load scratch test. In this work, the optical constants of PHPS-derived films were systematically studied for the first time. An antireflection effect was observed in the composites revealing their two-component nature associated with (i) the refractive index of the SiOxNy matrix film and (ii) the embedding of a SWCNT filler into the SiOxNy matrix. The curing method of PHPS was shown to significantly affect the resulting properties of the films. In addition to being used as protective multifunctional coatings for SCs, both SiOxNy/SWCNT composites and SiOxNy matrix films also function as broadband optical antireflective coatings. Furthermore, due to the very low friction coefficients observed in the mechanical tests, they show potential as scratch resistant coatings for mechanical applications.

Time Efficient & Cost Effective Online teaching tool with iConcepts in Orthodontics for DDS students @ UoM

Background Traditional teaching methods in Orthodontics include plaster models and photos which have been used for decades, however due to the nature of being static still images its difficult for 3-Dimensional (3D) changes in Orthodontics teaching, which has posed immense challenges as the learner is unable to clear concepts on the different planes that affect the final tooth positions not to mention the protracted treatment time ranges from 12 months (simple cases) to 36 months (complex cases). In 2024 with variety of platforms such as videos, 3D animations, interactive changes in face and teeth can be added to teaching tools for Orthodontics. Furthermore, orthodontic movements can pose difficulty in understanding the changes particularly in growing children adding to the 4th dimension. At UQ (Naser-ud-Din, 2015) and internationally (Bridges, 2015) provided experience with creating online teaching modules highlighting its strengths of flexibility, ease of access on demand and global presence. UQ developed SBLi -Scenario Based Learning interactive for Postgraduate Orthodontic students who found it highly engaging, with self-reflective and self-assessment elements useful. (Khoo et al., 2023; Naser-ud-Din, 2016). Generally simulations can be expensive to create (Kröger et al., 2017) and it’s essential to explore cost effective simulation teaching tools with industry partners for authentic learning experience. Aims There is a gap in the dental education sector, particularly with emerging CADCAM (Computer Assisted Design and Computer Assisted Manufacture), which can be used to enhance the learning of core concepts in biomechanics with the aid of 3D simulated online learning. This is reflected particularly for the university students in undergraduate courses who need to feel confident and clinically ready on graduation as Dentists. Thus, greater expectations to be aligned with current technological processes in dentistry. Over the past 5 years, in particular, there has been exponential improvements by the industry providing 3D simulations for treatment planning and patient communication, commonly referred to as the GPS for smile transformations. The aim of this presentation is to highlight the time efficiency and cost effectiveness of the learning tool in sync with contemporary demands in Orthodontics to provide authentic learning platform that prepares the clinician for real patients. Material & Methods Currently the CAD CAM technology provide 3D simulations as open access to general public and doctors portal which can be utilized for teaching core concepts related to biomechanics foundations for student learning, engagement and self-assessment. This project envisages to create a novel forum encompassing education revolution as massive changes in delivery will occur with speed and efficiency internationally with onlinelearning demands. Hence, robust online presence with an interactive textbook such as iConcepts in Orthodontics under the banner of UoM to assist students in Doctor of Dental Surgery at MDS shall pave the way to learning needs for the future. Results The purpose of iConcepts a digital interactive online textbook is to create lifelong learning opportunities in safe space for visual, auditory and kinesthetic with quizzes for interactive learning of concepts without pressure in class learning and feeling judged by peers. Interactive 3D Orthodontic learning directly translates into clinical applications for various orthodontic cases. In the past decade CAD CAM has become clinically relevant particularly with Clear Aligner Therapy adding to higher precision and patient satisfaction. Moreover, it is imperative to have Long Term Retention (LTR) (Irvine, 2020) of learning new tasks. It is essential that students in dentistry are aware of the digital workflows and have clinical preparedness on graduation as it’s the future and certainly here to stay. Both qualitative and quantitative data on student experience shall be collected and analysed to seek out the best practices and processes for instruction of delivery in Orthodontics for DDS cohort in particular and lifelong learning for all ages in general encompassing time efficiency and cost effectiveness. Conclusion The current iConcepts is developed by the author with Apple Education and prototype is being assessed with MSc Data Science cohort at UoM. Furthermore, it is refined by Master of Science Software Engineering students at UoM. Future Recommendations Novel teaching tools shall be marketed to developing universities internationally assisting the dissemination of information a flagship for UoM and revenue generation for department of Education at UoM. In future there will be more and more demand towards interactive concepts clarification (Poblete et al., 2020) and self-assessments hence iConcepts provides that ideal platform. Such technologies will become more prevalent in the future particularly with AI and translated into different languages/ sectors of education. Various faculties that showcase start to finish particularly lengthy/complex outcomes can benefit with timelapse videos and 3D CADCAM for clarity and comprehension for the entire process such as patient journey throughout treatment in Orthodontics.

Ten Years of Fashion Design Research Scientometric Analysis of Research: Research Overview, Frontiers and Evolutionary Paths

Background and Aim: Fashion design is a highly creative, interdisciplinary field that covers many aspects such as clothing, accessories, and textiles. Through creative design, material selection, process technology, etc., provide people with unique, beautiful, and practical fashion products and services. There has been a significant surge in research activity in the field of fashion design over the past decade, and by reviewing the data it was found that there is an academic gap in the bibliometrics of Fashion Design. The purpose of this study is 1) To study the research overview of Fashion Design. 2) To analyze the research frontiers of Fashion Design. 3) To analyze the evolution Path of Research Frontiers of Fashion Design. Materials and Methods: The key steps in retrieval: (1) Select database; (2) Enter "Topic"; (3) Select Document Type; (4) Select Document Language; (5) Enter Document Release Time Scope. Enter Topic="Fashion Design". Document types are article, proceeding paper, and English review from 2014-01-01 to 2022-12-31 for recent research. Book Citation Index-Science and Book Citation Index-Social Science & Humanities were excluded, leaving 1,049 documents. Common scientometric software includes CiteSpace, HistCite, Loet Tools, SciMAT, and VOSviewer. This study uses VOSviewer (version 1.6.19) for visualizing and analyzing scientific literature, helping researchers identify patterns, trends, and relationships in data. Results: The result of this research is that there are many prolific authors, Countries, and Publishers in this research field. There are three research fronts: "Impact", "Consumption" and "Industry". The evolution path of the research fronts starts from "Clothing Design" in 2014-2018. and "Arts", to "Innovation" in 2018-2019, to "Creativity" in 2019-2020, then to "Technology" and "Sustainability" in 2020-2021. Conclusion: The quality of articles in the "Fashion Design" research field is generally higher, with more research and very active. Research Frontiers: There are three research fronts: "Impact", "Consumption" and "Industry" The fashion design field’s focus on influence, consumption, and industry reflects its increasing emphasis on business and social impact. Evolution Path of Research Frontiers: The evolutionary path of the research frontier ranges from “Costume Design” and “art” in 2014-2018, to “Innovation” in 2018-2019, to “Creativity” in 2019-2020, and then to “technology” in 2020-2021 and “Sustainable development”. After 2021, it will be "Impact ", "Consumption" and "Industry". The evolution path of the research frontier reflects the shift in the development direction of the field of fashion design from single design and art to more design and art: diversification and comprehensiveness. From focusing on innovative ideas to technology and sustainable development to market, consumer, and industry development, it reveals the changes and evolution in the field of fashion design in the pursuit of excellence, sustainable development, and social impact.

High-pressure thermal conductivity, speed of ultrasonic measurements and derived elastic modulus of sandstones with different porosity

The effect of pressure on thermal conductivity is an important for understanding the heat transfer processes in modeling applications in geothermal reservoirs and for optimization of the technology of geothermal energy extraction processes. The primary factors affecting the economics of any geothermal energy recovery process are the amount of heat present in the geothermal reservoir and rate of heat extraction, which strongly depend on the thermal properties of the reservoir rocks, which are functions of both temperature and pressure. The present paper aims to study the variation of thermal conductivity of five sandstone samples from the Germany Geothermal Field with various total (open and close) porosities of (6.8, 13.0, 15.44, 21.3, and 21.5%) with pressure up to 203 MPa, to overcome the existing lack of thermal conductivity data for the geothermal reservoir modeling. The improved steady-state heat-flow technique (contact method) was used to precisely (with an uncertainty of 4%) measure the thermal conductivity of the sandstone samples. Unlike previous studies, in the present work the effect of the contact thermal resistance on the measured values of thermal conductivity has been taken into account using a calibration procedure to increase the accuracy and reliability of the measured data. The results show that with the increase of the pressure at a fixed temperature of 293.15 K, the thermal conductivity of sandstone is linearly increasing with pressure from 0.52 to 1.73 GPa−1 depending on sandstone structural and mineralogical composition, porosity, and other characteristics, which falls in the same range reported by other authors for rock samples from different geothermal fields. The derived values of the thermal conductivity pressure coefficient are crucial for geothermal studies in order to effectively use the geothermal resources of the region, and are useful for scientific applications such as the development and testing of the accuracy, reliability, and predictive capability of existing thermal models of geothermal reservoirs. Based on the present experimental results, statistical analysis (correlation analysis) was revealed between the measured thermal conductivity of sandstone samples and open and close porosities. The role of closed and open porosities on the pressure dependence of thermal conductivity and elastic moduli is discussed. For the first time, we experimentally observed the difference of the influence of the open and closed porosities on the thermal conductivity and elastic properties of sandstones. It was experimentally confirmed that the effect of closed porosity on the thermal conductivity of sandstones is significantly greater than that of open porosity by 15 to 20%. The obtained results show that it is of great importance to study the changes in the thermal properties of the sandstones under pressure at realistic reservoir conditions for geothermal studies.