Unstable Production Research Articles

Experimental studies and pore-scale modeling of hydrate dissociation kinetics at different depressurization rates in a cubic hydrate simulator

Natural gas hydrate (NGH) is a promising energy resource that has triggered a race for scientific innovation in energy and environmental research. However, there still faces the challenges of low-efficiency hydrate dissociation and unstable gas production during the hydrate production. Clarifying the kinetic mechanism of hydrate dissociation is the key to improving the efficiency of “phase-transition to gas-supply” in hydrate-bearing sediment. This study successfully conducts hydrate dissociation experiments with different depressurization rates in the Cubic Hydrate Simulator (CHS). A novel dissociation kinetic model integrating the hydrate pore-scale morphology and its evolutions are established, and the sensitivities of the kinetic and thermal parameters are discussed in detail. The mathematical relationship between the hydrate saturation and reaction area is quantitatively analyzed for the hydrate formation and dissociation kinetics. The history matching simulation with the newly developed model achieves an excellent agreement with the experimental results. The full-lifecycle kinetic behaviors of the hydrate dissociation in the depressurization experiments are finely characterized. It is found that the evolutions of the hydrate saturation (SH) and temperature (T) spatial distributions exhibit strong heterogeneous characteristics in the vessel due to the phase transition and heat transfer effects. In addition, this reveals that the relatively high depressurization rate can lead to a more significant dissociation rate in the depressurization stage. This provides a new reliable and adaptable method for describing the hydrate dissociation kinetics in the porous media.

Efficient nata de coco production of Komagataeibacter nataicola driven by microbiota-fermented coconut water: Biological and structural characteristics

Nata de coco is a traditional fermented food, chemically known as bacterial cellulose (BC), widely used in the food industry, personal care, and biomaterial areas. In the nata de coco industry, microbiota-fermented coconut water (FCW) has been regarded as a highly efficient medium for improving BC synthesis by Komagataeibacter spp. However, its effects on the biological properties of the strains of Komagataeibacter and structural characteristics of BC remain unknown, resulting in unstable production and BC quality. This study aimed to explore the biological properties of K. nataicola, the characteristics of BC structure and reasons for the efficiency under the effect of FCW. The results showed that FCW could increase the BC yield of K. nataicola by 2.03–4.75 times, the uridine diphosphate glucose pyrophosphorylase activity by 10–45.3 times, and the hexokinase, phosphofructokinase, or pyruvate kinase activities by 2 times. The extracellular metabolite profile of K. nataicola showed that its glycolysis/gluconeogenesis pathway was significantly stimulated and the utilization of erythritol obviously increased. These phenomena might be attributed to the use of ethanol, lactate, xylitoland mannitol in FCW by K. nataicola. In addition, the structural characteristics of BC produced in FCW included higher number of hydrogen bonds, thinner fibrils, a looser three-dimensional network, improved porosity and greater mechanical strength. This study offered novel insights into the BC synthesis of K. nataicola and the BC structural characteristics cultivated in FCW, providing valuable references for the efficient production and potential applications of both nata de coco and BC.

Performance effects of insulating and non‐insulating cost allocations in stable and unstable production environments

AbstractFirms allocate significant amounts of common costs, and these allocations have implications for performance evaluation and remuneration. Non‐insulating cost allocations distribute costs based on same‐period relative performance, creating a contemporaneous interdependence between managers that in turn adds uncertainty to the link between effort and performance. In contrast, insulating cost allocations are independent of relative performance during the period and can thus be determined with greater certainty ex ante. In an experiment, we predict and find that managers' effortful performance in a stable production environment—where the pre‐allocation return for effort is constant—is higher when costs are allocated via an insulating allocation compared to when costs are allocated via a non‐insulating allocation. We further find that in an unstable production environment—where the pre‐allocation return for effort can vary from period to period—there are no differences in performance between the allocation methods when managers face a lower return for effort. Conversely, when managers face a higher return for effort in this environment, performance is greater when costs are allocated via an insulating allocation. Taken together, overall performance in the unstable production environment is greater when managers work under insulating cost allocations, suggesting the net effects of cost allocation methods are similar in each type of production environment. As such, our study identifies an important cost—lower effortful performance—of using non‐insulating methods to allocate common costs.

A Comprehensive Review of Theories, Methods, and Techniques for Bottleneck Identification and Management in Manufacturing Systems

With the advancement in global market integration, manufacturing enterprises face increasingly fierce competition, making the development of intelligent manufacturing systems a key factor in enhancing market competitiveness. However, manufacturing systems are characterized by varying characteristics of manufacturing resources and strong interdependencies, which make production control more complex. A bottleneck refers to the issue where the manufacturing system’s actual production capacity is less than or equal to the demand placed on a resource. After extensive research, scholars have concluded that the definition, identification methods, and related studies on bottlenecks are not fixed but depend on the specific research subject and the type of bottleneck. Therefore, scholars suggest that only by accurately defining the bottlenecks within a system can appropriate models be employed for prediction, thereby avoiding issues such as inefficient resource allocation and delivery delays, or implementing measures to minimize these negative impacts. Particularly under unstable production conditions, dynamic bottlenecks are likely to occur, making the prediction and identification of bottlenecks under dynamic environmental conditions crucial. Currently, there is still a lack of research in real-time state sensing and integration, as well as a lack of systematic review of related research. To fill this research gap, this review comprehensively introduces the current state and achievements in bottleneck research within manufacturing systems, focusing on bottleneck categories, identification, shifting, and management. It also provides an outlook on future research trends and directions in the study of manufacturing system bottlenecks.

Enhance Productivity In The Garment Industry Through A Modified Value Stream Mapping Approach

The objective of this study is to overcome problems that occur in the garment industry, the company has tried to develop an agile system to increase productivity in this industry. The garment company that focusses on the production of woven bottoms and outerwear, noted that women's woven bottoms products have the highest demand throughout 2022. However, the company was unable to meet Brand demand of 3.5%. Production data shows defects in products, low quality raw materials, and unstable production processes. A modified Value Stream Mapping (VSM) methodology is use to consider all aspects of production. The results of traditional VSM and Value Stream Analysis Tools (VALSAT) analysis include current state and future state, identification of value added and non-value-added elements during the production process, as well as setting priorities to reduce waste in the production process, especially in inventory (19%), defective parts (17%), and transportation (15%). Based on the VALSAT matrix, Process Activity Mapping (33.5%), Supply Chain Response Matrix (21.6%), and Demand Amplification Mapping (15.3%) were obtained. The findings of this research are Pilot Run, which succeeded in becoming an agile and reliable system during the production process. Through the application of the methodology combined with VSM the results have improved compared to the traditional VSM method. This proves that this method is effective in overcoming takt time, cycle time, man power, and value-added ratio. Limitations of this research were also discussed, including that this research only focused on women's woven bottom products only on the production workflow. Kata Kunci: Agile System, Enhance Productivity, Garment Manufacturing, Lean Manufacturing, Value Stream Mapping.

Shale pore characteristics and their impact on the gas-bearing properties of the Longmaxi Formation in the Luzhou area

Deep shale has the characteristics of large burial depth, rapid changes in reservoir properties, complex pore types and structures, and unstable production. The whole-rock X-ray diffraction (XRD) analysis, reservoir physical property parameter testing, scanning electron microscopy (SEM) analysis, high-pressure mercury intrusion testing, CO2 adsorption experimentation, and low-temperature nitrogen adsorption–desorption testing were performed to study the pore structure characteristics of marine shale reservoirs in the southern Sichuan Basin. The results show that the deep shale of the Wufeng Formation Longyi1 sub-member in the Luzhou area is superior to that of the Weiyuan area in terms of factors controlling shale gas enrichment, such as organic matter abundance, physical properties, gas-bearing properties, and shale reservoir thickness. SEM is utilized to identify six types of pores (mainly organic matter pores). The porosities of the pyrobitumen pores reach 21.04–31.65%, while the porosities of the solid kerogen pores, siliceous mineral dissolution pores, and carbonate dissolution pores are low at 0.48–1.80%. The pores of shale reservoirs are mainly micropores and mesopores, with a small amount of macropores. The total pore volume ranges from 22.0 to 36.40 μL/g, with an average of 27.46 μL/g, the total pore specific surface area ranges from 34.27 to 50.39 m2/g, with an average of 41.12 m2/g. The pore volume and specific surface area of deep shale gas are positively correlated with TOC content, siliceous minerals, and clay minerals. The key period for shale gas enrichment, which matches the evolution process of shale hydrocarbon generation, reservoir capacity, and direct and indirect cap rocks, is from the Middle to Late Triassic to the present. Areas with late structural uplift, small uplift amplitude, and high formation pressure coefficient characteristics favor preserving shale gas with high gas content and production levels.

Enhanced energy storage system efficiency for remote area-based DC microgrid

This article suggests a hybrid storage system-based DC microgrid to supply the needs of remote areas with variable loads demands. This would help solve problems like limited energy storage systems, complicated consumption, and unstable power production from renewable sources. Energy storage is an attractive option for isolated zone; however, a single storage unit may not be sufficient owing to constraints in capacity, power, energy density, and life cycle. consequence, this study is concerned with hybrid energy storage systems battery/supercapacitor, which combine the most advantageous characteristics of various energy storage technologies to attain relevant performance. Furthermore, the supervision energy management technique based decoupling frequency is designed with low pass filter to separate the current to tow elements, low frequency current absorbed by the battery and high frequency current that absorbed by the supercapacitor. Furthermore, PI controllers are employed to control the DC link voltage, and the current of battery and supercapacitor. Energy management control plays an important role to improve the system performance, ensure power allocation among source, storage devices, and load consumption, and to maintain the battery and supercapacitor at their limitation states of charge (SOC), the system must be able to match the load requirements during a shortage and absorb any surplus power provided by wind energy. To confirm the achievement of the objectives of this study, the comparative simulation between battery storage alone and hybrid storage system combined of battery and Supercapacitor. The simulation results show that the hybrid storage battery and supercapacitor allow to increases the stability of DC link voltage with an overshoot less than 1.5% compared to 7.5% when battery alone and fast dynamic response. in addition, reduces the battery stress and increases its lifetime in the case of hybrid storage.

Optimization Design of Deep-Coalbed Methane Deliquification in the Linxing Block, China

The production of deep-coalbed methane (CBM) wells undergoes four stages sequentially: drainage depressurization, unstable gas production, stable gas production, and gas production decline. Upon entering the stable production stage, the recovery rate of deep CBM wells is constrained by bottom hole flowing pressure (BHFP). Reducing BHFP can further optimize CBM productivity, significantly increasing the production and recovery rate of CBM wells. This paper optimizes the deliquification process for deep CBM in the Linxing Block. By analyzing the production of deep CBM wells, an improved sucker rod pump deliquification process is proposed, and a method considering the flow in the tubing, annulus, and reservoir is established. Using the production data of Well GK-25D in the Linxing CBM field as an example, an optimized design of the improved rod pump deliquification process was undertaken, with design parameters including the depth of the sucker rod pump, the stroke length, and stroke rate. The results show that the improved process significantly lowers the pressure at the coalbed, enhancing CBM well production by 12.24%. The improved sucker rod pump process enriches deliquification technology for deep CBM, offering a new approach for its development and helping to maximize CBM well productivity.

Offshore produced water treatment by a biofilm reactor on the seabed: The effect of temperature and matrix characteristics

In many industrial processes a large amount of water with high salinity is co-produced whose treatment poses considerable challenges to the available technologies. The produced water (PW) from offshore operations is currently being discharged to sea without treatment for dissolved pollutants due to space limitations. A biofilter on the seabed adjacent to a production platform would negate all size restrictions, thus reducing the environmental impact of oil and gas production offshore. The moving bed biofilm reactor (MBBR) was investigated for PW treatment from different oilfields in the North Sea at 10 °C and 40 °C, corresponding to the sea and PW temperature, respectively. The six PW samples in study were characterized by high salinity and chemical oxygen demand with ecotoxic effects on marine algae S. pseudocostatum (0.4%<EC50<2.7%). In continuous operation over a year, MBBR achieved a stable COD removal of 64 ± 5% at 10 °C and 68 ± 8% at 40 °C. Batch experiments revealed that most dissolved compounds were removed (up to 63%) within 3 h of treatment. High temperature (40 °C) was a key parameter to achieve a faster kinetics with degradation constant rate (k) up to eight-fold faster compared to 10 °C. Alongside contaminants removal, PW toxicity was also reduced (64–89%) during MBBR at both temperatures, hot and cold. The toxicity reduction was most likely related to the elimination of dissolved organic compounds, such as phenols, naphthalenes and BTEX. The biofilm was able to handle PW with high oil in water content from unstable production, as well as high salinity. Thus, MBBR seems to be a realistic solution to treat PW with complex and variable composition by removing harmful components towards the zero harmful discharge goal.

The preparation, property and hydration mechanism of ultra high performance concrete with metakaolin substitution for silica fume

In recent years, there has been a growing body of research on the use of metakaolin (MK) in Ultra-High Performance Concrete (UHPC) to address the issue of unstable production yields and quality of industrial by-product Silica fume (SF). However, the current scientific literature tends to focus primarily on performance enhancements, often neglecting to elucidate the underlying mechanisms responsible for these improvements. In this study, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), nuclear magnetic resonance (NMR), nanoindentation technology, and Mercury Intrusion Porosimeter (MIP) were employed to establish the correlation between mechanical properties and hydration products, microstructure, and micromechanical properties. The results indicate that the judicious addition of MK can enhance the Al/Si ratio, prolong the C-A-S-H chain length, thereby increasing the percentage of high-density C-A-S-H, reducing the volume of C-A-S-H gel pores, optimizing UHPC pore structure, and ultimately leading to improved mechanical properties.

Development of Mexican and Turkish Automotive Industries in Historical Perspective

Purpose: The purpose of our article is to examine the Mexican and Turkish automotive industries in a historical perspective, because a historical analysis will be able to show us why the automotive industries of the country we are considering are not among the world's leading automotive industries. Additionally, the course of historical data over time can also support the analysis. Therotical Reference: For the first time, David (1985) put forward that it is necessary to examine the process of innovation of new products based on new technologies in a historical perspective, and David (2000, 2001) stated that the ergodic steady increase in production in sectors and industries depends on the sector or industry being able to create a unique development path. He stated that it was. He stated that the reason why there is no consistent ergodic production increase in sectors or industries is that it has a path-dependent development structure. According to David, path dependence may have been caused by an event or market formation that occurred in the recent or distant past. Method: It has been revealed that a past event for the Turkish automotive industry caused the formation of a new socio-cultural structure, leading to a path-dependent development in more or less all sectors, but especially in the automotive sector. This path-dependent development structure seems to have caused an unstable production structure in the automotive industry. When we look at the efforts to produce domestic automobiles throughout history, it is understood that there is always a tendency to be hindered or to think that they are being prevented. Results and Conclusions: Although there has not been a historical process similar to that in Turkey in the Mexican automotive industry, the fact that stable and ergodic production increases have been experienced in the industry, especially in the recent period, indicates that the automotive industry, which started as the assembly industry of foreign companies, has entered the process of creating a new path or creating a path with recent developments. We can say. In this process, it can be said that Mexico is a border neighbor with the USA and the investments of the three major automotive industry companies of the USA, which is one of the largest producing countries in the automotive industry, in Mexico, played a major role. Implication of research: In reaching this conclusion, in our study, the automotive industry history of the countries we discussed were examined and the annual production figures in the automotive industry in the last decade were discussed. In examining whether there were developments in the past of the countries that could lead to path dependency, the breaking point where path dependency occurred in Turkey, in the Ottoman period, was clearly identified and it was revealed that the events that took place after this date strengthened the path dependency. Past historical events for Mexico were examined and events that could affect the development of the automotive industry were discussed. Originality of article: Thus, we can say that, on the one hand, we tried to contribute to the literature and developments on the path dependency approach, which says that history is decisive, and on the other hand, a different perspective was brought to the developments in the automotive industry.

Modeling Climate Change Issues in Indonesia Based on Media Headlines

Climate change has become a global issue affecting all countries in the last decades. This phenomenon poses a concern to Indonesia as it is one of the climate change’s epicenters. Various studies have shown that climate change can harm multiple community activities, such as unstable agricultural production, decreased people’s health, and global warming. This study tried to model and analyze climate change topics discussed in the media. Finding hidden topics from texts can provide clues and information regarding public conversation surrounding climate change, such as public thoughts, perceptions, and readiness to mitigate the possible adverse effects of climate change. In order to identify hidden subjects from the corpus, this work modeled climate change issues in Indonesia using the latent Dirichlet allocation (LDA) algorithm to analyze texts from Indonesian media headlines. As many as 7,000 headline data from five online media were collected from 2017 to 2021 using web scraping techniques. The proposed approach produced eight topics related to climate change, which were determined by the highest coherence value of 0.560. Those topics were renewable energy, carbon emissions, environmental management, development economics, international cooperation, policy/regulation, rehabilitation, and disaster. Based on the results, the model could sufficiently describe the theme of discussion in society and photograph public thoughts and the government’s readiness in the form of policies and regulations in dealing with the climate change phenomenon.

Integrating Rooftop Agriculture and Atmospheric Water Harvesting for Water‐Food Production Based on Hygroscopic Manganese Complex

AbstractThe integration of atmospheric water harvesting and rooftop agriculture presents a promising solution for decentralized water and food supply in urban areas. However, the degradation of adsorption material kinetics after scaling up, coupled with fluctuations in solar energy, results in reduced and unstable water production. Herein, a composite adsorbent composed of manganese (II)‐ethanolamine complexes incorporated into a hierarchical and interconnect polypyrrole‐doped matrix is developed. This structure significantly reduces vapor diffusion resistance—a crucial factor impeding rapid scale‐up kinetics, enabling water uptake of 2.54 g g−1 at 90% RH, with 62% of water released within 30 min, facilitating daily multiple capture‐release cycles. Incorporating a hybrid desorption mode that combines PV electrical and solar heating further achieves stable and high‐yield water production. Ultimately, through simulation and feasibility verification, the atmospheric water‐irrigated rooftop farm realizes water and food production yield of 879.9 gwater m−2sorbent day−1 and 1.28 kgfood m−2device within 14 days without human intervention and independent of external water inputs. These findings highlight the potential of integrating AWH technology with rooftop farming as a pathway to sustainable urban development through decentralized water and food co‐production.

A fully coupled compositional wellbore/reservoir model for predicting liquid loading in vertical and inclined gas wells

Liquid loading presents a formidable challenge for mature gas wells, often resulting in substantial economic losses. Traditional research has predominantly centered on the analysis of gas-liquid two-phase flow within the wellbore to predict critical gas velocity or rate, aiding in identifying the onset of liquid loading. This study introduces a fully coupled compositional wellbore-reservoir simulator designed to detect liquid loading in both vertical and inclined gas wells. Leveraging the drift-flux model to evaluate flow pattern transitions, this simulator employs pressure or rate constraints at the wellhead as boundary conditions. It comprehensively captures the flow dynamics in both the wellbore and reservoir, unveiling significant changes in gas production rate, water production rate, gas velocity, flow regime, and the reserved position of the liquid film under liquid-loaded conditions. Moreover, the accumulation of liquid at the bottom hole leads to increased reservoir pressure and gas saturation near the wellbore. The simulator predicts a typical unstable production period, emphasizing its crucial role in implementing effective strategies to mitigate liquid loading. This paper investigates the capability of the coupled wellbore-reservoir model to characterize transient liquid loading phenomena from a systematic perspective. The proposed model can function as a real-time tool for predicting the status of liquid loading in gas wells.

Assessment of Production and Risks of Consumption of Artisanal Refreshing Drinks (Bissap, Gnamankoudji) in Haut Sassandra (Daloa-Côte d'Ivoire)

Introduction: The production and consumption of artisanal refreshing drinks (Bissap, Gnamankoudji) in the Haut Sassandra region are anchored in local culture. These artisanal drinks are experiencing considerable growth despite their artisanal and unstable production. Objective: The objective of this study is to diagnose the production of these artisanal drinks and to assess the potential risks associated with their consumption in the Haut Sassandra region. Methodology: A cross-sectional and retrospective survey was carried out with producers to make the diagnosis and with consumers to identify some main conditions linked to the consumption of these drinks. 52 producers were investigated, and 780 consumers were submitted to a questionnaire, for a total of 832 people audited. Results: Bissap and Gnamankoudji have many similar unit operations. In addition, Bissap undergoes heat treatment. The drinks are mostly packaged in used pots. The main conditions encountered were diarrhea (8.3% and 8.7%), belly bloating (2.4% and 2.8%), fever (1.80% and 2.30%), nausea (1.80% and 1.90%), vomiting (0.90% and 1%) respectively after consumption of Gnamankoudji and Bissap. Conclusion: The study collected data on the production of artisanal drinks and the risks incurred by consumers. The consumption of these drinks represents a major risk for public health.

Triacylglycerol stability limits futile cycles and inhibition of carbon capture in oil-accumulating leaves.

Engineering plant vegetative tissue to accumulate triacylglycerols (TAG, e.g., oil) can increase the amount of oil harvested per acre to levels that exceed current oilseed crops. Engineered tobacco (Nicotiana tabacum) lines that accumulate 15% to 30% oil of leaf dry weight resulted in starkly different metabolic phenotypes. In-depth analysis of the leaf lipid accumulation and 14CO2 tracking describe metabolic adaptations to the leaf oil engineering. An oil-for-membrane lipid tradeoff in the 15% oil line (referred to as HO) was surprisingly not further exacerbated when lipid production was enhanced to 30% (LEC2 line). The HO line exhibited a futile cycle that limited TAG yield through exchange with starch, altered carbon flux into various metabolite pools and end products, and suggested interference of the glyoxylate cycle with photorespiration that limited CO2 assimilation by 50%. In contrast, inclusion of the LEAFY COTYLEDON 2 (LEC2) transcription factor in tobacco improved TAG stability, alleviated the TAG-to-starch futile cycle, and recovered CO2 assimilation and plant growth comparable to wild type but with much higher lipid levels in leaves. Thus, the unstable production of storage reserves and futile cycling limit vegetative oil engineering approaches. The capacity to overcome futile cycles and maintain enhanced stable TAG levels in LEC2 demonstrated the importance of considering unanticipated metabolic adaptations while engineering vegetative oil crops.

Structures, performances and applications of green biomass derived carbon in lithium-ion batteries

Most countries worldwide have committed to reaching carbon neutrality by the end of the century, with the aim to achieve Net Zero before 2060. To reduce the dependency of energy demands on fossil fuels, use of renewable energy and its gradual transition into the overall energy portfolio becomes increasingly critical. The solar and wind energy accounts for a major part of renewable energy. Considering unstable and noncontinuous production of electricity from these two sources, energy storage becomes essential. Lithium-ion batteries (LIBs) have become the most favorable choice of energy storage due to their good electrochemical performance (high capacity, low charge leakage and good cycle performance) and safety, in particular for portable (3C products, electric vehicles and drones) and stationary applications as well as for emergency electricity supply. However, the specific capacity of graphite, the most common commercial anode material, is reaching its theoretical limit, posing great challenges for improving the overall capacity of LIBs. It is therefore necessary to develop anode materials of higher capacity and better cycle performance. Biomass-derived carbon materials are ideal candidates for further enhancing the performance of LIBs due to their special microstructures, functional diversity and easy structure regulation. Most of these materials can reach capacities exceeding 500 mAh g-1, even the best for more than 1,000 mAh g-1 combined with other anode materials. This review provides an in-depth analysis of diverse carbon sources derived from biomass, categorized based on their distinct structural characteristics, with the focus on evaluating the current roles and bottlenecks of carbon as a component of the electrode materials used in LIBs. The failure mechanisms associated with biomass-derived carbon in LIBs are summarized, with potential solutions to these issues being proposed. The potential challenges and prospects for biomass-based LIBs are identified and thoroughly discussed. Overall, this review aims to serve as a resource for the strategic design and advancement of carbon-based materials, to achieve next-generation LIBs of superior performance.

Preparation and Application Prospects of Nano Chitin

Over recent years, the global ecological environment has deteriorated, and it is urgent to use environmentally friendly renewable energy as an alternative. Chitin nanofiber (ChNF) appears in the public view as a biomass material with biodegradability and biocompatibility. This paper elaborates on the preparation methods, application fields, and prospects of chitin nanofiber. Firstly, the preparation steps of chitin nanofibe including purification of chitin and the preparation of nano size chitin are listed. Based on this, the common chitin purification methods, such as the acid-base method, Ethylene diamine tetra acetic acid (EDTA) auxiliary method, and microwave method, are discussed. In terms of the nano fibrillation, the mixing of chemical and mechanical methods is introduced to improve the products’ purity and yield. Secondly, due to the unique features of chitin nanofiber, its potential in biomedical, food security, and absorbent for waste water treatment is promising. However, the large-scale application of nano chitin still faces some obstacles including large energy consumption in the preparation process, high catalyst treatment cost, and unstable production rate. This paper expects that future researchers can focus on achieving the large-scale and high-quality production of chitin nanofiber and exploring its great potential.

A Combination of Association Rules and Optimization Model to Solve Scheduling Problems in an Unstable Production Environment

Production problems have a significant impact on the on-time delivery of orders, resulting in deviations from planned scenarios. Therefore, it is crucial to predict interruptions during scheduling and to find optimal production sequencing solutions. This paper introduces a selflearning framework that integrates association rules and optimisation techniques to develop a scheduling algorithm capable of learning from past production experiences and anticipating future problems. Association rules identify factors that hinder the production process, while optimisation techniques use mathematical models to optimise the sequence of tasks and minimise execution time. In addition, association rules establish correlations between production parameters and success rates, allowing corrective factors for production quantity to be calculated based on confidence values and success rates. The proposed solution demonstrates robustness and flexibility, providing efficient solutions for Flow-Shop and Job-Shop scheduling problems with reduced calculation times. The article includes two Flow-Shop and Job-Shop examples where the framework is applied.

Smart grid projects in the pan-European energy system

Purpose. To provide a comparative and comprehensive analysis of the smart grid projects funded by the H2020 ENERGY and FP7-ENERGY programs. Methodology. As part of the text analysis, the authors evaluated smart grid projects’ results in a sample using text mining methods. Based on statistical analysis and concept-based method, the most significant outcomes of smart grid projects were identified. Findings. A detailed review of the results shows that project teams of the H2020 ENERGY and FP7-ENERGY programs mostly relied on the existing experience which helped to form further development for standardization of tools, conduct planning, or derive specific management actions aimed at smart energy consumption. The majority of these solutions were applied for digitalizing small commercial consumers and for integrating isolated renewable sources in the most effective way. The projects considered the possibilities of electric vehicles used to solve environmental problems and balancing unstable electricity production from renewable sources with Li-ion stationary batteries, tools for effective interaction of users of smart grids, and integration of isolated renewable sources in centralized energy networks. Originality. Based on statistical and machine analysis, the most significant results of smart grid projects were identified. N‑grams of expressed keywords used in the texts of project results were used to present and visualize the textual description of smart grid projects. Practical value. The results might be helpful for the European policymakers and scientific advisers seeking to further promote and ameliorate the pan-European energy system.