Unit Operations Research Articles

Electric Multiple Unit Spare Parts Vendor-Managed Inventory Contract Mechanism Design

As electric multiple unit (EMU) operations and maintenance demands have expanded, spare parts supply chain management has become increasingly crucial. This study emphasizes the supply challenges of EMU spare parts, including inadequate minimum inventory levels and prolonged response times. Redesigning the OEM–railway bureau vendor-managed inventory (VMI) model contract incentive and penalty system is the key goal. Connecting the spare parts supply system with its characteristics yields a game theory model. This study analyzes and compares the equilibrium strategies and profits of supply chain members under different mechanisms for managing critical spare parts. The findings demonstrate that mechanism contracts can enhance supply chain performance in a Pareto-improving manner. An in-depth analysis of downtime loss costs, procurement challenges, and order losses reveals their effects on supply chain coordination and profit allocation, providing railway bureaus and OEMs with a theoretical framework for supply chain decision-making. This study offers theoretical justification and a framework for decision-making on cooperation between OEMs and railroad bureaus in the management of spare parts supply chains, particularly for extensive EMU operations.

Technoeconomic assessment of a sorghum-based biorefinery using DWSIM PRO: A comparative study with aspen plus.

Technoeconomic assessment of a sorghum-based biorefinery using DWSIM PRO: A comparative study with aspen plus.

Novel approaches to engineering autolysis: A scalable alternative for recovery of bioproducts.

Novel approaches to engineering autolysis: A scalable alternative for recovery of bioproducts.

The Professionalism of Treasurers Managing Education Unit Operational Assistance Funds (Study in East Bolaang Mongondow Regency)

This study aims to determine, analyze and describe the professionalism of treasurers managing Education Unit Operational Assistance (BOSP) funds in East Bolaang Mongondow Regency. The professionalism of the treasurer is a crucial aspect in ensuring accountability, transparency, and effectiveness in the use of education funds. The research method used was a qualitative method with a descriptive qualitative approach with data collection techniques through interviews, observations and documentation studies. The research sample amounted to 10 people who were determined using purposive sampling technique. The results showed that the professionalism of the treasurers was not optimal, most of the treasurers had carried out their duties in accordance with applicable regulations, but there were still some obstacles such as lack of technical training, limited understanding of the latest regulations, and delays in fund disbursement which had an impact on the effectiveness of budget management. This study recommends capacity building through continuous training and a more structured monitoring and evaluation system to improve the performance of school treasurers.

A Dual‐Functional Membrane for CO2 Capture and Electrocatalytic Reduction

Carbon capture, utilization, and sequestration technologies are critical for limiting global temperature rise. CO2 capture and utilization are traditionally performed as separate unit operations. Integrating them requires using dual‐functional materials and offers a promising pathway to overcome energy demand and cost limitations. In this study, we demonstrate the fabrication of an electrocatalytic membrane (eCatMem) by laser‐induced graphene processing of a gas‐separating membrane, enabling CO2 reduction to formate. The membrane exhibits CO2/N2 permselectivity of ~20, ensuring comparable performance when operating with pure CO2 or a 10% CO2/N2 gas mixture. The eCatMem achieves current densities of 10–50 mA/cm2 with a Faradaic efficiency of ~70% for formate production. This is the first of its kind demonstration of integrated membrane electrochemical reactive separation to form a liquid capture media that is also a product. This approach utilizes simple, low‐cost materials and processes and offers a scalable way to integrate CO2 capture and utilization.

Comparative Analysis of Anion Exchange Membrane Adsorbers for Endotoxin Removal During Ultrafiltration and Diafiltration Buffer Preparation

ABSTRACTDuring the manufacturing of drug substances (DS), endotoxins are a commonly monitored contaminant and checked to ensure the safety and quality of the final product. In this study, we investigated endotoxin removal by commercial anion exchange membrane adsorbers during buffer preparation for an ultrafiltration and diafiltration (UFDF) unit operation as a risk mitigation strategy to meet DS endotoxin specifications. A bracketing design study was used to compare two quaternary amine (Q) modified membranes and one guanidinium functionalized hybrid adsorber for endotoxin removal from spiked buffers representing UFDF start and diafiltration buffer matrices. For the UFDF start buffer, Q‐based membrane adsorbers were effective at the removal of endotoxin to the limit of detection in low ionic strength conditions, with one adsorber effective up to 24 mS/cm. Switching to a more complex UFDF diafiltration buffer, Q‐based membrane adsorbers were impacted by additional buffer components. The guanidinium‐based hybrid membrane adsorber demonstrated endotoxin reduction to the limit of detection from both buffer matrices, showing removal across a wide pH range (4.7–8.3) and conductivity as high as 43 mS/cm. These results demonstrate an operational window for buffers and selected membrane adsorbers to mitigate risk by limiting endotoxin contamination prior to UFDF operations in pharmaceutical applications.

Полевые исследования модульных рабочих органов комбинированного почвообрабатывающего орудия

Works on creation of new and modernization of existing aggregates and combined machines are carried out both in Russia and abroad. The leading role in them is given to reducing energy consumption and increasing the quality of soil tillage. Huge variety of climatic and soil conditions dictate to designers their own rules for creation of modern aggregates and machines. Existing machines cope with the set tasks quite well, but works on their improvement should be continued. This requires from researchers the manifestation of new design and scientific solutions. The scientific novelty consists in the development of a new design of the frame of a tillage implement with interchangeable modular working bodies, as well as in the determination of qualitative and energy indicators of the unit operation. The purpose of research is to determine the traction resistance of combined tillage tool in field conditions depending on the design and technological parameters of modular working bodies. The strain gauge method was used in the field research. When processing the data of field experiments, the maximum traction resistance for two disk plow working bodies reached the value Fxyz = 5013.20 N, for a pair of disk batteries - Fxyz = 3135.82 N, for two knife rollers - Fxyz = 5337.81 N. On the basis of the obtained experimental data it is possible to design combined aggregates consisting of several types of working tools. In this case, the selection of implements will be carried out based on the tractor traction class. For a certain class of tractor it will be possible to select a certain combination of working tools with the required design and technological parameters. Such combinations will further improve the quality and efficiency of soil tillage and reduce fuel consumption during work.

Digital Twin for Upstream and Downstream Integration of Virus-like Particle Manufacturing

Virus-like particles (VLPs) have the potential to become a versatile carrier platform for vaccination against multiple diseases. In the light of short process development timelines and the demand for reliable and robust processes, metabolic modeling of cell culture processes offers great advantages when coupled with a Quality-by-Design (QbD) development approach. A previous work was able to demonstrate the accurate prediction of HEK293F PiggyBac cell concentration as well as VLP titer and metabolite production with a reduced metabolic model. This work presents the reduced metabolic model for a more productive cell line Sleeping Beauty and emphasizes the need for model re-parameterization when the producer cell line changes. The goal of precise prediction for a fed-batch and continuous HEK293 cultivation can, therefore, be achieved. In terms of decision-making for downstream unit operations, a soft sensor for the prediction of main impurities like proteins and DNA was introduced for the first time for the production of lentiviral vectors with several terms describing the release of impurities like DNA and proteins, growth-related protein production, and enzymatic degradation activity associated with cell dissociation in an accurate manner. The additional information can contribute to a more efficient design phase by reducing experimental effort as well as during cultivation with data-based decision-making. With the aid of real-time process data acquisition through process analytical technology (PAT), its predictive power can be enhanced and lead to more reliable processes.

Microalgal biorefineries in sustainable biofuel production and other high-value products.

Microalgal biorefineries in sustainable biofuel production and other high-value products.

A review of mathematical models in unit operations of glutinous and non-glutinous rice processing

A review of mathematical models in unit operations of glutinous and non-glutinous rice processing

Engineering oxide speciation in CoMnOx catalysts for achieving an ideal selective oxidation of benzyl alcohol at room temperature with atmospheric pressure air.

Engineering oxide speciation in CoMnOx catalysts for achieving an ideal selective oxidation of benzyl alcohol at room temperature with atmospheric pressure air.

Anomaly Detection Method for Hydropower Units Based on KSQDC-ADEAD Under Complex Operating Conditions.

The safe and stable operation of hydropower units, as core equipment in clean energy systems, is crucial for power system security. However, anomaly detection under complex operating conditions remains a technical challenge in this field. This paper proposes a hydropower unit anomaly detection method based on K-means seeded quadratic discriminant clustering and an adaptive density-aware ensemble anomaly detection algorithm (KSQDC-ADEAD). The method first employs the KSQDC algorithm to identify different operating conditions of hydropower units. By combining K-means clustering's initial partitioning capability with quadratic discriminant analysis's nonlinear decision boundary construction ability, it achieves the high-precision identification of complex nonlinear condition boundaries. Then, an ADEAD algorithm is designed, which incorporates local density information and improves anomaly detection accuracy and stability through multi-model ensemble and density-adaptive strategies. Validation experiments using 14-month actual operational data from a 550 MW unit at a hydropower station in Southwest China show that the KSQDC algorithm achieves a silhouette coefficient of 0.64 in condition recognition, significantly outperforming traditional methods, and the KSQDC-ADEAD algorithm achieves comprehensive scores of 0.30, 0.34, and 0.23 for anomaly detection at three key monitoring points, effectively improving the accuracy and reliability of anomaly detection. This method provides a systematic technical solution for hydropower unit condition monitoring and predictive maintenance.

Повышение энергетической эффективности ГТУ газоперекачивающего агрегата ГПА-Ц-16/76 за счет комплексного использования вторичных энергоресурсов

Russia has the largest reserves of natural gas in the world. In our country, trunk gas pipelines are traditionally used to deliver natural gas from the extraction site to consumers. The construction, maintenance and operation of trunk gas pipelines require considerable financial resources, so reducing the costs of pumping natural gas by increasing the energy efficiency of gas turbine units due to integrated use of secondary energy resources is of considerable interest. The conducted studies have been carried out using available methods of thermodynamic calculation of the internal combustion engine cycle, determination of the components of its thermal balance and thermal calculation of equipment for the utilization of secondary thermal energy resources. After the integrated use of secondary energy resources, an analysis of the expenditure part of the energy balance of the gas turbine unit has been carried out. It has shown that 16,000 kW (41,7 %) of the thermal energy of the incoming part of the energy balance is used to drive the gas compressor, 9,899 kW (25,8 %) is used to drive the low- and high-pressure compressors, 11,311 kW (29,4 %) is discharged with combustion products, and external heat losses amount to 1,152 kW (3 %). Compared with the basic gas turbine unit, heat losses with combustion products have decreased by 65 %. The energy-saving measures to use secondary energy resources have allowed us to reduce the consumption of natural gas during the operation of the gas turbine unit in the nominal mode compared with the basic gas turbine unit by 23 %. Considering the generation of electric energy due to the use of energy of excess pressure of the flue gas and heat during heating of the network water of the heat supply system of the gas pumping station, 35420 kW or 92,2 % of the supplied energy has been used beneficially.

Assessing the applicability of manual trackers in PV-micropower stations in the North

Relevance. Electricity supply to remote settlements in the North is carried out using autonomous power systems, which are a combination of diesel generator units. These units consume significant volumes of expensive diesel fuel. Reducing the volume of fuel consumption by using renewable energy facilities has practical relevance and demand. Aim. Evaluation of the possibility of using manual tracker units in micro-power PV-power plants operating as part of autonomous power systems in the North by performing in-kind studies. Methods. Methods of determining the efficiency of using manual and automatic tracker units for PV-power plants, and processessing experimental data. Results and conclusions. The authors have identified the indicators of increase in electricity generation before and after the introduction of tracker units. The volumes of reduction in diesel fuel consumption in an autonomous power system are calculated depending on the type of tracker unit. Recommendations for the sustainable operation of manual tracker units for micro-power PV-power plants are formed. The authors substantiated the impossibility of using manual tracker units in small and large-capacity solar energy facilities due to high labor costs. The obtained results of applied research can be used to update the existing list of technical measures to improve PV-power plants located in the North. The capital cost of manual tracker units is 70–80% less than their automatic counterparts. This type of units increases the average daily electricity generation from a PV-power plant by 17–18% provided that the orientation of the PV-panels relative to the Sun changes hourly. Based on the results of the technical and economic assessment, it was determined that in the case of introducing manual tracker units into a PV-power plant with an installed capacity of 20 kW in the village of Toyon-Aryy, an average annual saving of diesel fuel of up to 8.8 tons is achieved with a payback period of up to 11.7 years. The carbon footprint in the energy system under study is reduced in the form of a decrease in CO2 emissions to 27.7 tons per year.

Conceptual Process Design and LCA Evaluation of Precious Metals Recovery from Waste PCBs

Abstract The present study explores the development and evaluation of precious metals (PM) recovery processes designed to extract silver (Ag), gold (Au), and palladium (Pd) from copper anode slimes (CAS) generated via the black copper route from waste printed circuit boards (PCBs). Two conceptual process flowsheets—Route 1 (conventional) and Route 2 (polar aprotic solvent)—were designed and simulated adopting established and novel metallurgical methods using FactSage™ and HSC Chemistry 10 software. Both routes employed leaching-precipitation techniques; however, Route 1 utilized conventional acid-salt precipitation methods, whereas Route 2 incorporated with a novel approach based on polar aprotic solvent leaching. The results showed that the simulated recovery rates for Ag, Au, and Pd were high across both processes, achieving 94.8%, 99.1–99.3%, and 99–99.2%, respectively. To evaluate the environmental impacts, a life cycle assessment (LCA) was conducted using openLCA, with the treatment of CAS in kg as the functional unit and a gate-to-gate system boundary. It was found that Route 1 had lower environmental impact potentials, yielding acidification potential (AP) of 0.52–0.93 kg SO₂ eq, eutrophication potential (EP) of 0.67–1.21 kg PO₄3⁻ eq, and global warming potential (GWP) of 61.83–110.4 kg CO₂ eq. Conversely, Route 2 exhibited higher AP (0.59–1.26 kg SO₂ eq), EP (0.7–1.33 kg PO₄3⁻ eq), and GWP (75.1–134.9 kg CO₂ eq), primarily due to the use of CuCl₂, DMF, and ethanol in the Au and Pd recovery steps. Furthermore, scenario analysis revealed that CAS with higher PM content resulted in greater environmental burdens compared to CAS with a higher proportion of base metals. This finding suggests that while PM recovery remains the primary objective, base metal removal entails a lower environmental cost. Additionally, it is important to mention that both routes are identical up to the Ag electrorefining stage, which emerged as the most impactful unit operation, contributing approximately 65% and 98% of the total environmental impacts in Route 1 and Route 2, respectively, primarily due to the high demand for silver nitrate. Overall, Route 1 demonstrated superior environmental performance while maintaining high recovery rates, making it a more sustainable option for industrial-scale CAS processing. These findings provide valuable insights for optimizing PM recovery strategies while minimizing environmental impacts in the circular economy framework. Graphical Abstract

Developing downstream processes for the purification of recombinant proteins and small molecules from Nicotiana benthamiana biomass.

Nicotiana benthamiana (Australian tobacco) has become a major host for plant-based recombinant protein production, especially using transient expression. Once a candidate protein has been designed and produced in a suitable variety (e.g. facilitated humanized glycosylation) under reproducible conditions (e.g. in a vertical farm), the product must be extracted from the biomass and purified to meet the application requirements. For example, >95% purity is often expected for biopharmaceuticals. Here, we review options for and challenges of recombinant protein isolation from N. benthamiana biomass taking inspiration from related host systems when appropriate. Specifically, we first introduce typical properties of the biomass to be processed and then discuss options to harvest it and extract the product, for example, using homogenizers. This includes conditioning steps like heat treatment and means to ensure product integrity. Next, we highlight the advantages and limitations of different clarification operations given the high particle loads typically present in N. benthamiana extracts. Afterwards, we look at product purification using both membrane and chromatographic unit operations focusing on the specific aspects of plant molecular farming. We briefly discuss the potentials of modelling and artificial intelligence in downstream process development and conclude with a short outlook on future developments.

IMPLEMENTASI SISTEM INFORMASI AKUNTANSI DI DALAM KEBERLANJUTAN UMKM DI INDONESIA

This study focuses on the implementation of Accounting Information Systems (AIS) and Information Technology (IT) in supporting the sustainability of advanced economic units. The objective of this research is to characterize economic units, examine the application of AIS, explain the effectiveness of AIS and IT within these units, and investigate the role of IT specialists. To achieve these objectives, a comprehensive analysis was conducted to understand the nature, structure, and operations of advanced economic units. This study explores how AIS is implemented and utilized in these units by examining the processes, procedures, and technologies involved in the collection, storage, processing, and reporting of both financial and non-financial data. In addition, this research evaluates the impact and effectiveness of AIS and IT on the overall performance and sustainability of economic units, highlighting both the benefits and challenges associated with the adoption and integration of these systems. The findings indicate that the effective implementation of AIS and IT has a positive impact on the performance of economic units, including improved decision-making capabilities, operational efficiency, and enhanced financial reporting. This study also provides valuable insights into the application of AIS and IT in advanced economic units and underscores the importance of these systems in ensuring sustainability. The findings of this research may serve as a guide for decision-makers and practitioners in optimizing the use of AIS and IT.

Electric-Field Nanobubble-Enhanced Progress in Anaerobic Digestion Unit Operations: Biogas Upgrading and Up- and Down-Stream Water and Sludge Treatment Operations.

An integrated approach is sorely needed to treat biogas emanating from anaerobic digesters (AD) which is cost-effective, in terms of upgrade/purification to ~95-98% methane needed for pipeline injection. This is a very pressing environmental and waste-management problem. At present, biogas water-/solvent-washing operations require significant capital investment, with high operational and maintenance costs. In the present study, we deployed a facile and efficient novel nanobubble-formation approach using applied electric fields to boost biogas-enrichment operations: we achieve substantial methane enrichment via selective CO2 and H2S take-up in water in the form of nanobubbles. This enables an integrated waste-processing vision using cutting-edge engineering-science advances, and making anaerobic digestion a circular-economic and practical reality, that can be deployed at scale-initially developing at the small scale-and points the way for low-energy CO2 capture in the form of nanobubbles by dint of the electric-field approach. In addition, we carried out nanobubble generation using various gases for water treatment for both up- and down-stream sludge-containing (waste)water, achieving meaningful operational successes in AD operations and organic-fertiliser production, respectively.

IT resource relatedness and the search for agility: a complementarity perspective

ABSTRACT Should organisations force business units to use shared IT resources, or should business units, notwithstanding the potential for duplication and higher costs, be allowed to select their own IT resources? If successful, efforts to expand IT resource relatedness will increase the sharing of IT resources across business units leading to higher business unit agility. Alternatively, forced IT resource sharing could remove IT optionality, thereby impeding business unit operations and agility. To investigate these opposing viewpoints, we consider how systems of complements involving three distinct IT resource classes (IT infrastructure, applications, and data) affect business unit agility. Which IT resources are shared matters as the complementarity effects from sharing various IT resources may be different from the marginal effects of sharing just one type of IT resource. We investigate these arguments using data from 120 organisations. Analysis shows that sharing applications and data enables business unit agility, while sharing IT infrastructure hurts business unit agility. Follow-up qualitative interviews with senior IT executives support and extend these findings. In combination, the results of our quantitative and qualitative studies enhance our understanding of how IT resource relatedness influences business unit agility, contingent on both the level and type of IT resource sharing.

Continued Testing and Modeling of the AirSquared All-Metal Tritium Scroll Pump

The implementation of fusion energy requires the processing of the deuterium-tritium mixture used to fuel the reaction. Many gas processing operations require either a gas-motive force or a pressure gradient across a system; both are achieved using vacuum pumps. However, because of the material challenges of working with tritium, specialized pumps are required that use only metal on wetted surfaces. This prevents tritium retention and degradation of materials such as oils and polymers and reduces the generation of tritiated waste. Typical gas handling systems for tritium operations involve metal bellows pumps, all-metal scroll pumps, and metal turbomolecular pumps, depending on the pressure requirements. With the industry standard Normetex Type 15 m3/h (typically referred to as the Normetex 15) pump no longer available, the fusion market requires viable alternatives. In this study, we test an American-made pump, the AirSquared V16H034A-C01, and compare its performance to the Normetex. A performance model of the AirSquared pump is also produced, which can be applied to general process models to generate an accurate description of pressures and flows through various unit operations.