Downstream Operations Research Articles

Enhancing Textile Wastewater Treatment Performance: Optimization and Troubleshooting (Decision Support) via GPS-X Model

Textile factory water consumption could be optimized to minimize the generation of wastewater, reduce treatment costs, and promote resource recovery. However, downstream plant operation and management is a prime concern in the textile industry, particularly bringing treated wastewater effluent to an acceptable discharge limit. The aim of the study was to optimize key process control parameters to the observed operational challenges of existing processes and suggest an operational guide to the operators and decision makers to enhance the treatment performance in GPS-X. The formulated troubleshooting and decision support strategy, and the optimization results of waste-activated sludge in the primary and secondary clarifiers, was within the range of 15 ± 5 m3/d and 83 ± 7 m3/d, respectively, with a recycle-activated sludge flow of 150 ± 10 m3/d. The sludge retention time was 5 ± 1 d and 6.7 ± 0.5 d in the secondary and primary clarifiers, respectively. The addition of a carbon source in the form of molasses had a flow of 0.5 ± 0.05 m3/d, and the variation in the influent due to wastewater characteristics and rainfall was optimized to 600 ± 50 m3/d. The optimum air flow into the aeration tank was 550 ± 5 m3/hr and saved 91.5% of energy in the optimized process. Thus, the study is indispensable for the effective and efficient operation of the plant and serves as a good guide to the plant operators and decision makers for the best course of action.

Evaluation of a hollow fiber membrane contactor reactor for reactive extraction in biodiesel production

A polypropylene hollow fiber membrane contactor reactor (HF-MCR) was used to evaluate the performance of a reactive extraction process for biodiesel production. The process involved the transesterification of soybean oil with methanol, catalyzed by sodium hydroxide. The experimental methodology assessed the impact of oil flow rate and methanol/oil molar ratio on the biodiesel (FAME) production rate, triglyceride reaction rate, and glycerin concentration in the final biodiesel product. The results demonstrated that, by employing a countercurrent configuration, is possible to extract the glycerin from the biodiesel-rich phase with methanol, achieving both the reaction and the separation stages in the same equipment. The best results were obtained at a methanol/oil molar ratio of 4:1 and an oil flow rate of 0.4 L h−1, leading to a triglyceride conversion rate of 0.14 mol h−1 and a FAME production rate of 0.24 mol h−1, equivalent to 34 % conversion and 56 % yield, respectively. The final biodiesel product showed a low concentration of glycerin, measuring only 0.06 % wt. This investigation highlights the potential of employing membrane contactors technology for the biodiesel production process, reducing the processing time by eliminating the biodiesel/glycerol separation stage, and therefore bringing down the load of downstream purification operations.

Dimethylsilanediol from silicone elastomers: Analysis, release from biopharmaceutical process equipment, and clearance studies

Polysiloxanes are considered one of the most important commercial families of synthetic elastomers. They are frequently employed in biopharmaceutical manufacturing equipment as flexible single-use solutions due to superior material properties and compatibility with diverse sterilization methods. Extractables and leachables (E&L) testing is essential in qualifying such equipment, involving extraction studies to assess the potential release of compounds from plastic components for risk assessment. Silicone releases oligomeric siloxanes and small hydrolysis products, with dimethylsilanediol (DMSD) being the main hydrolysis product found in significant concentrations in aqueous process solutions. DMSD presents challenges for analysis, requiring specifically tailored analytical methods to detect it, which are commonly not applied in standard E&L screening tests. In biopharmaceutical manufacturing, it is relevant to consider the potential of DMSD to repolymerize into silicone oil when specific process parameters are altered. This may lead to interactions with drug ingredients, including proteins, resulting in the formation of aggregates. We synthesized and characterized DMSD using X-ray structure analysis and established an HPLC method with a refractive index detector to investigate the release of DMSD from commercially available silicone tubing used in drug manufacturing following autoclaving and irradiation. Subsequently, we assessed typical biopharmaceutical downstream operations for effectively removing this compound from the process stream.

Application of PAT in pharmaceutical manufacturing: model‐based control of particle size distribution in anti‐solvent aided crystallization

AbstractBACKGROUNDCrystallization plays a key role in determining the physiochemical properties of an active pharmaceutical solid, which are crucial for drug product performance as well as processibility in downstream operations. Precise control of crystallization parameters is hence necessary to maintain drug efficacy and consistency during active pharmaceutical ingredient (API) manufacturing. In our earlier work on crystallization of dexlansoprazole API, an empirical model was established with reactor temperature and addition time of anti‐solvent identified as critical process parameters (CPPs) and particle size distribution (PSD) as critical quality attribute (CQA). In this study we demonstrate model‐based control of particle size when disruptive incidences occur under a process analytical technology framework.RESULTSExperiments highlighted the deviation in PSD (CQA) on performing a planned disruption event in the form of temporary shutting down the anti‐solvent feeding dosing pump. Once the deviation had occurred due to process disruption, the desired set‐point of particle size was achieved by making the desired changes estimated from model equations for individual CPPs. The change was signaled to the temperature control system or the dosing pump, which then set the revised process conditions in real time during crystallization.CONCLUSIONThe study utilizes an empirical model to achieve the desired particle size by making suitable real‐time changes in CPP in view of process disruption. The case study aligns with the paradigm of quality by design, which expects manufacturers to understand their processes and their products and have in‐built controls to ensure that the resulting product consistently meets the approved specifications. © 2023 Society of Chemical Industry.

Shop floor dispatching with variable urgent operations based on Workload Control: An assessment by simulation

AbstractMeeting customer time requirements poses a major challenge in the context of high‐variety make‐to‐order companies. Companies need to reduce the lead time and process urgent jobs in time, while realising high delivery reliability. The key decision stages within Workload Control (WLC) are order release and shop floor dispatching. To the best of our knowledge, recent research has mainly focused on order release stage and inadvertently ignored shop floor dispatching stage. Meanwhile, urgency of job is not only related to its due date, but also affected by the dynamics of shop floor. Specifically, urgency of jobs may decrease at downstream operations in the job's routing, since priority dispatching for urgent jobs accelerates production speed at the upstream operations. And occupying production resources increases the waiting time of non‐urgent jobs at workstation. This phenomenon leads to the change of urgency of jobs. Misjudgement of urgent jobs therefore may result in actual urgent jobs not being processed in time. In response, the authors focus on shop floor dispatching stage and consider the transient status of urgent operations in the context of WLC. The urgency of jobs is rejudged at the input buffer of each workstation, which is firstly defined as urgent operations and non‐urgent operations. Using simulation, the results show that considering the transient status of urgent operations contributes to speeding up production for actual urgent jobs and meeting delivery performance both in General Flow Shop and Pure Job Shop. In addition, percentage tardy performance is greatly affected by norm levels, especially at the severe urgent level. These have important implications on how urgent operations should be designed and how norm level should be set at shop floor dispatching stage.

Are genetic drift and stem cell adherence in laboratory culture issues for cultivated meat production?

Mesenchymal stem cell-based cultivated meat is a promising solution to the ecological and ethical problems posed by traditional meat production, since it exhibits a protein content and composition that is more comparable to original meat proteins than any other source of cultivated meat products, including plants, bacteria, and fungi. Nonetheless, the nature and laboratory behavior of mesenchymal stem cells pose two significant challenges for large-scale production: genetic drift and adherent growth in culture. Culture conditions used in the laboratory expose the cells to a selective pressure that causes genetic drift, which may give rise to oncogene activation and the loss of "stemness." This is why genetic and functional analysis of the cells during culture is required to determine the maximum number of passages within the laboratory where no significant mutations or loss of function are detected. Moreover, the adherent growth of mesenchymal stem cells can be an obstacle for their large-scale production since volume to surface ratio is limited for high volume containers. Multi-tray systems, roller bottles, and microcarriers have been proposed as potential solutions to scale-up the production of adherent cells required for cultivated meat. The most promising solutions for the safety problems and large-scale obstacles for cultivated meat production are the determination of a limit number of passages based on a genetic analysis and the use of microcarriers from edible materials to maximize the volume to surface proportion and decrease the downstream operations needed for cultivated meat production.

Pseudo-affinity capture of K. phaffii host cell proteins in flow-through mode: Purification of protein therapeutics and proteomic study

K. phaffii is a versatile expression system that is increasingly utilized to produce biological therapeutics – including enzymes, engineered antibodies, and gene-editing tools – that feature multiple subunits and complex post-translational modifications. Two major roadblocks limit the adoption of K. phaffii in industrial biomanufacturing: its proteome, while known, has not been linked to downstream process operations and detailed knowledge is missing on problematic host cell proteins (HCPs) that endanger patient safety or product stability. Furthermore, the purification toolbox has not evolved beyond the capture of monospecific antibodies, and few solutions are available for engineered antibody fragments and other protein therapeutics. To unlock the potential of yeast-based biopharmaceutical manufacturing, this study presents the development and performance validation of a novel adsorbent – PichiaGuard – functionalized with peptide ligands that target the whole spectrum of K. phaffii HCPs and designed for protein purification in flow-through mode. The PichiaGuard adsorbent features high HCP binding capacity (∼25 g per liter of resin) and successfully purified a monoclonal antibody and an ScFv fragment from clarified K. phaffii harvests, affording > 300-fold removal of HCPs and high product yields (70–80%). Notably, PichiaGuard outperformed commercial ion exchange and mixed-mode resins without salt gradients or optimization in removing high-risk HCPs – including aspartic proteases, ribosomal subunits, and other peptidases – thus demonstrating its value in modern biopharmaceutical processing.

Product safety aspects of plant molecular farming.

Plant molecular farming (PMF) has been promoted since the 1990s as a rapid, cost-effective and (most of all) safe alternative to the cultivation of bacteria or animal cells for the production of biopharmaceutical proteins. Numerous plant species have been investigated for the production of a broad range of protein-based drug candidates. The inherent safety of these products is frequently highlighted as an advantage of PMF because plant viruses do not replicate in humans and vice versa. However, a more nuanced analysis of this principle is required when considering other pathogens because toxic compounds pose a risk even in the absence of replication. Similarly, it is necessary to assess the risks associated with the host system (e.g., the presence of toxic secondary metabolites) and the production approach (e.g., transient expression based on bacterial infiltration substantially increases the endotoxin load). This review considers the most relevant host systems in terms of their toxicity profile, including the presence of secondary metabolites, and the risks arising from the persistence of these substances after downstream processing and product purification. Similarly, we discuss a range of plant pathogens and disease vectors that can influence product safety, for example, due to the release of toxins. The ability of downstream unit operations to remove contaminants and process-related toxic impurities such as endotoxins is also addressed. This overview of plant-based production, focusing on product safety aspects, provides recommendations that will allow stakeholders to choose the most appropriate strategies for process development.

Sustainable management in the slow fashion industry: carbon footprint of an Italian brand

PurposeEnvironmental impacts associated with the fashion industry concern society and require commitment to sustainable development goals from leading companies. The role of the luxury sector in setting trends and negotiating power within the supply chain can lead this industry towards sustainability. This study constructs a comprehensive operational flux inventory attributed to an Italian luxury garment brand, aiming to investigate and propose feasible strategies to reduce potential impacts coupled with their products.MethodsUnder the operational control criteria, a whole year of activities was tracked using mainly primary data from its management system. According to ISO 14064–1:2019, potential greenhouse gas emissions were classified, organized, and processed into six categories. The analysis, at the company level, covered the product’s complete life cycle, i.e., from cradle to the grave. The ecoinvent database considered preferentially local geography, and the cut-off system approach, therefore assigning emissions to the primary user.Results and discussionResults showed that the only unit in central Italy where the headquarter is located (excluding retail stores), producing 485,193 women’s clothing in a year, emitted 9804 t CO2 eq. Most of these impacts (69% or 6752 t CO2 eq) can be associated with indirect emissions related to raw products and materials, and about 93% of this amount results from the high-quality products used by the company. Transportation represents 14% of the total emissions, while the use phase accounts for about 13%. As a final step, six different mitigation scenarios were proposed and analyzed by focusing on non-core production activities, i.e., upstream, and downstream operations, and consumers’ habits. Once combined, these strategies can potentially reduce by about 25% the study case company overall emissions.ConclusionsAs a conclusion, exploring possible alternatives through environmental assessment tools can support strategies for achieving impact reduction. While aggressive changes can be done in non-core activities with excellent results, changes perceived by the customers can also be well desired to mark innovation and advances in the business mindset.

Modeling the Factors That Drive the Need for Inter-Facility Transfers to Downstream Services in US Emergency Departments

Improving emergency department (ED) care coordination requires analytics-based models that can integrate large patient-level and hospital databases to help formulate better transfer processes and policies across different hospital settings. This study develops a new empirical model to analyze over one million heart attack emergency department (ED) encounters between 2006-2014 to understand the factors that drive the need for inter-facility transfers (IFT) in different hospital settings. The resulting model has proven helpful for deriving public policy insights from this information. For instance, while we find that while healthcare IFT inequities and inconsistencies persist with ED discharge decisions because of some specific patient and hospital resource factors, these have been reduced significantly in the more recent post-reform period. We conclude by discussing the implications of using this empirical modeling approach for developing smarter policies and procedures for managing and benchmarking downstream healthcare operations practices in this disease area.

A crystallization case study toward optimization of expensive to evaluate mathematical models using Bayesian approach

ABSTRACT Crystallization process operated in MSMPR mode is of great relevance in manufacturing because of its low operational requirements and easy maintenance. However, to enhance product purity and downstream operations, one needs to handle trade-off among residence time, mean and spread of crystal size distribution. In this paper, we, therefore, study this multi-objective optimization problem (MOOP) to obtain the Pareto solutions using high-fidelity (HF) population balance equations. We parallely aim to develop an optimal Pareto front using Multi-objective Bayesian Optimization (MOBO) technique which exploits the qEHVI as the acquisition function to identify the optimization path. The results show that MOBO requires only 2.4% of HF functional calls compared to evolutionary approaches to generate similar quality results. This indicates the potential of MOBO in optimizing the time expensive MOOPs with minimum number of function calls, which can be easily extended for response surface-based optimization studies involving design of experiments.

AN ASSESSMENT OF INFLUENCE OF SELECTED CHARACTERISTICS OF FEED ON THE RESULTS OF BALL MILL GRINDING PROCESS COURSE FOR POLISH COPPER ORES

The article concerns issues related to the copper ore ball mill grinding process, operating at different technological parameters. The aim of the study was to investigate the influence of various operating parameters and feed characteristics on selected technological effects (comminution degree, yields of the finest particle size classes, ready for downstream flotation operations). The research program included grinding tests of two lithological types of Polish copper ore (dolomite and sandstone) and their mixtures in the proportions: 70% dolomite +30% sandstone and 30% dolomite +70% sandstone. Material was treated under wet and dry grinding in Bond’s ball mill. Three different grinding time were applied together with three levels of mill’s rotational speed. The feed material with three different particle size compositions was used in the rests. The results show that increases in yields of fine particle size fractions for each sample are dependent on the particle size composition of feed, grinding time and rotational speed of mill. Together with increasing of grinding time, fine particle size fraction contents increase too, especially for the coarse feed without fine particles. In general, higher comminution degrees were obtained for ore mixtures, the most favorable results for a mixture of 30% sandstone +70% dolomite, where S 50 equaled 358 and S 90 = 178. Correlation analysis showed that in fact all technological parameters under investigation were significantly related to the obtained comminution effectiveness.

Experimental Investigation of the Effect of Delay Time on Rock Fragmentation in Multi-Hole Bench Blasting

Rock fragmentation by blasting influences ore recovery and the cost of downstream operations. The development of electronic detonators makes it possible to improve fragmentation by controlling the initiation timing in blasting projects, and the effect of the mechanism of delay timing on rock fragmentation should be studied. Fragmentation of granite bench specimens with different initiation timing was investigated in blast experiments. Conclusions are obtained by studying the surface strain field and post-blast specimens. A total of six blasting tests were carried out on granite bench specimens with four boreholes each having a diameter of 10 mm and a length of 450 mm. Each borehole used pentaerythritol tetranitrate (PETN) as the explosive charge, which was approximately 4.84 g with a charge diameter of 5.5 mm. Delay times between adjacent boreholes in the same row were set as 0, 50, 100, 150, 200, and 250 µs. The surface strain field of the bench specimen under blast loading was analyzed using three-dimensional digital image correlation (3D-DIC) techniques based on two cameras that captured high-speed images. Additionally, the post-blast specimen was also observed and recorded. Fragments of each bench specimen were carefully collected, weighed, and sieved with a set of sieves, including very fine particles. According to the 3D-DIC analysis for bench specimens, the propagation pattern of the main strain concentration zone transformed from horizontal to vertical with the increase in inter-hole delay. The maximum blast excavation weight was obtained by the bench specimen with an inter-hole delay of 100 µs, while the bench specimen with the longest inter-hole delay (250 µs) obtained the minimum blast excavation weight. By combining the results for blast excavation weight with the results from fragment size distribution analysis of all specimens, the optimal inter-hole delay was 200 µs. Compared to simultaneous detonation, the median size was decreased by about 14.5% for the inter-hole delay of 200 µs. The results of experiments show that delay time significantly influences rock fragmentation, but the stress wave superposition in short delays cannot improve rock fragmentation. For long delays, the blast-induced crack propagation time should be regarded as an influential factor when choosing the proper delay time. The experimental findings of this study could provide a better understanding of the effect of the mechanism of delay time on rock fragmentation.

Recovery of dilute (bio-based) volatile fatty acids by adsorption with magnetic hyperthermal swing desorption

Adsorption followed by stepwise desorption to concentrate volatile fatty acids (VFAs) from very dilute aqueous streams is challenging and only a limited amount of VFAs can be collected at high concentration using N2-stripping. Here, we describe the preparation and use of superparamagnetic porous adsorbents to recover much larger fractions of VFAs in highly concentrated form from dilute aqueous streams than with the state-of-the-art N2-stripping technique. Our system is based on poly(divinylbenzene) (PDVB) impregnated with superparamagnetic magnetite nanoparticles (MNPs) synthesized by coprecipitation and functionalized with oleic acid (OA). The OA grafted MNPs (OA-MNPs) were embedded in the matrix of the polymer during suspension polymerization. The porous particles had an average size of 222 ± 40 µm with a surface area of 496 ± 10 m2/g and contained 11 ± 1 wt% MNPs with an average core size of 10 nm. VFAs adsorption from a dilute aqueous solution (containing 0.25 wt% of each acid) reached a saturation capacity of 43 g carboxylic acid per kg adsorbent,. The two-stage desorption was started with alternating magnetic field (AMF) heating at 25 mT and 52 kHz, followed by a hot N2 stripping stage removed 90 ± 9% of the water that had physically filled the pores during adsorption, and only 11 ± 2% of the loaded VFAs. Subsequently, 89 ± 3% of the VFAs were recovered almost water free using hot N2 stripping. Compared to sorbent regeneration and vapor fractionation by nitrogen stripping with a temperature gradient only, this new approach offers a much sharper acid fractionation from water, facilitating large energy savings in downstream operations.

Analisis Dampak Penyetopan Ekspor Emas terhadap Devisa dan Harga Emas dalam Negeri Di Masa Mendatang

The purpose of this study was to determine the impact of the stoppage of gold exports that had been planned by the government, both on the country's foreign exchange and on the price of gold in the country. The method used in this research is a literature study. Literature study in this research is a series of activities carried out using library data collection methods, reading and recording, and managing data obtained from various sources in an objective, systematic, analytical and critical manner which will address the results of this study namely; 1) to find out whether the gold export ban policy can affect the country's foreign exchange. 2) whether it will generate greater foreign exchange earnings due to added value. 3) and whether there will be an increase in domestic commodity prices, especially gold. Previously, Indonesia was in 7th place from 2018 to 2020 with gold production of 130 tons to 139 tons. Even so, the gold that Indonesia exports is only raw gold which will be turned into gold which is a finished material in other countries, and besides that, Indonesia also only has gold reserves of only 78.6 tons. Thus, Indonesia will not stop gold but will carry out downstream operations where exports continue but only the type of gold is different and can affect the country's foreign exchange.
 Keywords: Foreign Exchange, Export, Gold, Downstream, Commodity

Advances in high-throughput, high-capacity nonwoven membranes for chromatography in downstream processing: A review.

Nonwoven membranes are highly engineered fibrous materials that can be manufactured on a large scale from a wide range of different polymers, and their surfaces can be modified using a large variety of different chemistries and ligands. The fiber diameters, surface areas, pore sizes, total porosities, and thicknesses of the nonwoven mats can be carefully controlled, providing many opportunities for creative approaches for the development of novel membranes with unique properties to meet the needs of the future of downstream processing. Fibrous membranes are already finding use in ultrafiltration, microfiltration, depth filtration, and, more recently, in membrane chromatography for product capture and impurity removal. This article summarizes the various methods of manufacturing nonwoven fabrics, and the many methods available for the modification of the fiber surfaces. It also reviews recent studies focused on the use of nonwoven fabric devices in membrane chromatography and provides some perspectives on the challenges that need to be overcome to increase binding capacities, decrease residence times, and reduce pressure drops so that eventually they can replace resin column chromatography in downstream process operations.

Reviewing the Impact of Powder Cohesion on Continuous Direct Compression (CDC) Performance.

The pharmaceutical industry is undergoing a paradigm shift towards continuous processing from batch, where continuous direct compression (CDC) is considered to offer the most straightforward implementation amongst powder processes due to the relatively low number of unit operations or handling steps. Due to the nature of continuous processing, the bulk properties of the formulation will require sufficient flowability and tabletability in order to be processed and transported effectively to and from each unit operation. Powder cohesion presents one of the greatest obstacles to the CDC process as it inhibits powder flow. As a result, there have been many studies investigating potential manners in which to overcome the effects of cohesion with, to date, little consideration of how these controls may affect downstream unit operations. The aim of this literature review is to explore and consolidate this literature, considering the impact of powder cohesion and cohesion control measures on the three-unit operations of the CDC process (feeding, mixing, and tabletting). This review will also cover the consequences of implementing such control measures whilst highlighting subject matter which could be of value for future research to better understand how to manage cohesive powders for CDC manufacture.

Behavior of host-cell-protein-rich aggregates in antibody capture and polishing chromatography

Recent work has shown that aggregates in monoclonal antibody (mAb) solutions may be made up not just of mAb oligomers but can also harbor hundreds of host-cell proteins (HCPs), suggesting that aggregate persistence through downstream purification operations may be related to HCP clearance. We have examined this in a primary analysis of aggregate persistence through processing steps that are typically implemented for HCP reduction, demonstrating that the phenomenon is relevant to depth filtration, protein A chromatography and flow-through anion-exchange (AEX) polishing. Confocal laser scanning microscopy observations show that aggregates compete with the mAb to adsorb specifically in protein A chromatography and that this competitive interaction is integral to the efficacy of protein A washes. Column chromatography reveals that the protein A elution tail can have a relatively high concentration of aggregates, which corroborates analogous observations from recent HCP studies. Similar measurements in flow-through AEX chromatography show that relatively large aggregates that harbor HCPs and that persist into the protein A eluate can be retained to an extent that appears to depend primarily on the resin surface chemistry. The total aggregate mass fraction of both protein A eluate pools (∼ 2.4 – 3.6%) and AEX flow-through fractions (∼ 1.5 – 3.2%) correlates generally with HCP concentrations measured using enzyme-linked immunosorbent assay (ELISA) as well as the number of HCPs that may be identified in proteomic analysis. This suggests that quantification of the aggregate mass fraction may serve as a convenient albeit imperfect surrogate for informing early process development decisions regarding HCP clearance strategies.

Developing a parametric system model to describe the product distribution of steam pyrolysis in a Dual Fluidized bed

Steam pyrolysis is a thermochemical process that converts carbon-based materials into valuable gases. In general, the products of the reaction are syngas (H2,CO,CO2), low-molecular-weight hydrocarbon gases (methane, ethylene, and propylene), pyrolytic gasoline and oils, monoaromatic and polyaromatic species (tar), and carbonaceous residues (char) with ashes. However, the intricacy of the reactions comprising the process, the diversity of the product species, and the constraints linked to the sampling and measurement equipment, create a highly complex system. In this work, a method for data representation is presented based on a special Parametric System Model (PSM) that portrays product species measurements in a way that provides relevant information and valuable insights into the process. The method incorporates generic knowledge of the chemical nature of the reactions to create a constrained system in which the data can be expressed in parametric terms with meaningful statistical functions. The evaluated data were obtained from a high-temperature steam pyrolysis process performed in the 2–4-MW Dual Fluidized Bed reactor at Chalmers University using polyethylene as feedstock. The quantities of the hydrocarbon species detected in the gas product were taken for the PSM as a probabilistic system that can be described with a set of distribution functions. The carbon, hydrogen and oxygen balances were taken into account to build a constrained set of equations to find the parameters of the functions. The resulting model was proven to be useful as a prediction tool to quantify unmeasured carbon group species and to estimate process variables, such as the oxygen transport of the bed material. Also, it was demonstrated the potential of the model as a method to identify and estimate inconsistencies in the measurements, which improve the quality of the characterization data. The modeĺs outcomes find application in providing critical information for the control and evaluation of pyrolysis process and downstream operation of biorefineries.

Using semantic Geometric Dimensioning and Tolerancing (GD &T) information from STEP AP242 neutral exchange files for robotic applications

This article proposes the use of Geometric Dimensioning and Tolerancing (GD &T) information from STEP AP242 for robotic manufacturing applications. This information can be directly added to the relevant features of the 3D model as per Model Based Definition methodology during the design phase of the product life cycle. STEP AP242 neutral exchange files enable the availability of product definition at the downstream operations, thus completing the Digital Thread as part of Industry 4.0 practices. This article discusses two methods; using custom Unicode strings and the standard entities; for including GD &T using the STEP AP242 Edition 2 neutral file exchange format. A method to form a single Unicode string to add all the GD &T information to the STEP files is described in this paper. The GD &T information in the Unicode string is fully semantic and can easily be parsed to extract the relevant PMI for tolerance analysis. A novel process of extracting and interpreting the relevant PMI for robotic manufacturing applications is described in detail. This article discusses various applications of this information for robotic manufacturing through two use-cases using the second edition of the STEP AP242 standard.