Methods For Analysis Of Products Research Articles

Nitrogen Reduction Testing with Real-Time 15NH3 Yield Quantification Using Orbital Multiturn Time-of-Flight Mass Spectrometry.

Yield validation of dinitrogen reduction reaction (N2RR) catalysts with 15N isotope labeling experiments is frustrated by the high cost of 15N2 and the frequent occurrence of 15NH3 and 15NO x impurities in commercial 15N2 sources. Also, gas diffusion electrode (GDE) cell architectures are relevant to scaling N2RR but underexplored and limited by ex situ product analysis methods. To overcome these obstacles, we develop and demonstrate a protocol for N2RR catalyst testing using a scalable GDE cell architecture and specialized test station that facilitates in-line product analysis with multiturn time-of-flight mass spectrometry. This approach provides robust yield measurements through real-time monitoring of 15NH3 with ultrahigh mass resolution. The 15N-containing impurities are also monitored, allowing their influence to be mitigated. A minimum detectable yield of 6 pmol·cm-2·s-1 (at 2.00 sccm and utilizing a 5 cm2 electrode) for real-time 15NH3 yield rate measurements is achieved while using a cost-effective amount of 15N2 (<100 mL).

Investigation of glycogen-based synergistic systems with deep eutectic solvents as additives for enantioseparation in capillary electrophoresis

The enantioseparation of chiral drugs and the potential synergistic effect between deep eutectic solvents (DESs) and polysaccharide chiral selector (glycogen) were first investigated in capillary electrophoresis (CE). The results showed that significantly improved separations of six model drugs were observed compared with single glycogen system. After completing the optimization of separation conditions, the mechanism of DESs improving enantioseparations was studied by means of Statistical Product and Service Solutions (SPSS) analysis, ultraviolet spectroscopy and nuclear magnetic resonance (NMR) methods. It was the first time that synergistic systems based on DESs and polysaccharide chiral selector were established, and DESs were effective auxiliary additives to enhance the enantioselectivity of the glycogen system in CE.

Anodized CuO-based reusable non-enzymatic glucose sensor as an alternative method for the analysis of pharmaceutical glucose infusions: a cyclic voltammetric approach.

Analyzing pharmaceutical products is a quality control requirement in a production facility. This study presents a CuO electrode-based reusable non-enzymatic sensor as an alternative method for rapid analysis of glucose levels in glucose infusions. CuO is extensively employed as an electrode material in non-enzymatic glucose sensors. Conventionally, these electrodes are fabricated using chemical synthesis of CuO followed by immobilization to the electrode substrate. In contrast, here, Cu metal was mechanically modified to create a grooved surface, followed by electrochemical anodization and subsequent annealing process to grow a seamless CuO layer in situ with enhanced catalytic activity. The morphology of the electrodes was characterized using scanning electron microscopy (SEM) and X-ray diffractometry (XRD). The direct electrocatalytic activity of the developed CuO-modified electrode towards glucose oxidation in alkaline media was investigated by cyclic voltammetry in detail. The CuO-modified electrode commenced the oxidation process around 0.10V vs. Ag pseudo-reference electrode, demonstrating a significant reduction in the overvoltage for glucose oxidation compared to the bare Cu electrode. The sensor is capable of detecting glucose at low oxidation potentials such as 0.2V with a sensitivity value of 0.37 µA ppm-1, a wide linear range (80-2300ppm), limit of quantification (LOQ) of 1ppm, greater repeatability, 1% precision, 3% bias, a short response time (80s), good reproducibility and excellent reusability (196 consecutive attempts). The enhanced performance and cost-effectiveness make this sensor a promising alternative method for product analysis in glucose injection solutions.

Product analysis methods

Product analysis methods

Fast production and water-breakthrough analysis methods demonstrated using Volve Field data

When producing from conventional fields, the well rates are primarily constrained by the production-system in the early years of the field-life, while later in the field-life the production rates are primarily constrained by the reservoir deliverability. For the post-plateau production period, the reservoir deliverability will no longer potentially exceed the production-system well-rate constraints. Traditionally, analytical equations are used in a nodal analysis method that balances the pressure at the well inflow point from the reservoir (inflow performance relationship; IPR) with the pressure required for the vertical lift performance (VLP; or vertical flow performance; VFP) from the same point upward. A faster and simpler approach is proposed in the present study. Whereas, the classical IPR solutions are based on a constant well-rate solution of the diffusivity equation, use of a constant bottomhole pressure assumption can bypass the need for nodal analysis type pressure matching solutions to obtain the well rate. Instead, the well rate can be directly computed from the pressure decline in the reservoir and any production system capacity constraint can be imposed on the theoretical well rate due to the reservoir quality. The merits of the new approach are explained and illustrated by way of a detailed production analysis case study using open-access data from the Volve Field (Norwegian Continental Shelf). In addition, the case study of the Volve Field wells demonstrates a new water-breakthrough analysis method.

Flow Investigation and Optimization Design of a Radial Outflow Liquid Turbine Expander for Liquid CO2 Energy Storage System

Abstract The radial outflow liquid turbine expander (LTEROF) draws increasing attention for enhancing the efficiency of the liquid CO2 energy storage (LCES) system. However, the detrimental cavitation deteriorates the flow behavior, which demands an in-depth study of the flow physics and then effective attenuation. This study aims to effectively mitigate thermosensitive fluid cavitation and reduce energy dissipation. First, a preliminary expander design methodology taking into account the large specific volume variation of working fluid is implemented. Next, the entropy production analysis method (EPAM) is proposed to characterize energy dissipation and cavitation. Furthermore, the improved cavitation and turbulence models are validated through simulating Hord's liquid hydrogen hydrofoil. To suppress the cavitation and energy dissipation, the optimization design method based on the particle swarm optimization (PSO) algorithm together with the Kriging-based adaptive surrogate model is developed. Among them, the nonuniform relational B-splines and free form deformation (NURBS-FFD) method is applied to flexibly deform the profiles of nozzle and rotor, and a novel objective function incorporating vapor volume fraction and local entropy production rate (LEPR) is constructed to capture the cavitation and energy dissipation. During optimization, the optimizer is driven by the objective function to search globally toward the cavitation-resistance and low-dissipation geometry. With the optimization, the LEPR region shrinks and the cavitation is obviously weakened, the performance significantly improves both under design condition and under off-design conditions.

Corrosion of food grinding discs in gastro-intestinal environment

The need for food size reduction before consumption has led to the use of motorized grinding machine which operates on energized rubbing of two grooved cast-iron discs, and this unintentionally results in tribological degradation and corrosion of grinding discs into the ground food. The objective of this study was to carry out an assessment of corrosion susceptibility of grinding discs from different manufacturing methods in simulated gastro-intestinal environment. Six grinding discs from three states in Nigeria were selected for this study, based on manufacturing methods namely: rotary, cupola, and pit furnaces. Experimental techniques used for the study included: X-Ray Fluorescence spectroscope for determination of chemical composition and X-Ray Diffractometer was used for phase identification. Corrosion susceptibility of grinding discs on interaction with pseudo-body fluid was studied using potentiodynamic polarization scan and product analysis (gasometric) methods in simulated gastro-intestinal environment, typical of human stomach, as electrolyte. The electrolyte contained 2 g/L NaCl acidified to pH of 1.7 with HCl and regulated at 37 °C. Optical microscopy of the electrochemical samples was done for corrosion damage assessment. The key finding from the study was that all the grinding discs contain iron and silicon as dominant alloy elements, which existed predominantly as iron carbide and ferrosilicon phases. Corrosion of the discs in simulated gastric solution was well profound irrespective of the manufacturing method, though, with varying degree among the discs. The outcome of this study is applicable to food industries where cognitive measures may have to be taken on materials selection to minimise the risk of food contamination from materials corrosion.

Comparative study of the mechanism of natural compounds with similar structures using docking and transcriptome data for improving in silico herbal medicine experimentations.

Natural products have successfully treated several diseases using a multi-component, multi-target mechanism. However, a precise mechanism of action (MOA) has not been identified. Systems pharmacology methods have been used to overcome these challenges. However, there is a limitation as those similar mechanisms of similar components cannot be identified. In this study, comparisons of physicochemical descriptors, molecular docking analysis and RNA-seq analysis were performed to compare the MOA of similar compounds and to confirm the changes observed when similar compounds were mixed and used. Various analyses have confirmed that compounds with similar structures share similar MOA. We propose an advanced method for in silico experiments in herbal medicine research based on the results. Our study has three novel findings. First, an advanced network pharmacology research method was suggested by partially presenting a solution to the difficulty in identifying multi-component mechanisms. Second, a new natural product analysis method was proposed using large-scale molecular docking analysis. Finally, various biological data and analysis methods were used, such as in silico system pharmacology, docking analysis and drug response RNA-seq. The results of this study are meaningful in that they suggest an analysis strategy that can improve existing systems pharmacology research analysis methods by showing that natural product-derived compounds with the same scaffold have the same mechanism.

Simplification of the combustion mechanism of Jatropha biodiesel surrogate fuel and reaction path analysis

The objectives of this study were to explore the evolution process of the chemical reaction pathways in the combustion of a biodiesel surrogate fuel and to reduce the calculation burden in the numerical simulation of this combustion process due to the complicated mechanism. A mixture of methyl decanoate, methyl 9-decanoate, and n-heptane was selected as the Jatropha biodiesel surrogate fuel. A simplified combustion mechanism of the biodiesel comprising 170 components and 737 reaction components was formed by systematically simplifying 3299 components and 10806 reaction mechanisms using a multistep directed relation graph method, path flux analysis, and sensitivity analysis. The simplified mechanism was compared with the detailed mechanism and experimental data to effectively verify the accuracy of the mechanism. The simplified mechanism could reproduce the detailed mechanism, and the results were in good agreement with the experimental data in terms of the ignition time of a methyl decanoate/air mixture in a shock tube, the concentrations of the components generated in the combustion process of the biodiesel in a jet stirred reactor, and the flame propagation speed of methyl decanoate and n-heptane/air mixture. The rate of production analysis method was used to explore the main reaction pathways and the evolution process of important intermediate components in the Jatropha biodiesel surrogate fuel generated at high and low temperatures. Methyl decanoate and methyl 9-decanoate formed hydrogen peroxide ketone and oxy groups mainly through dehydrogenation, oxygenation, and isomerization at low temperatures. The high-temperature stage mainly involved bond-breaking decomposition reactions, partial dehydrogenation, and isomerization reactions of low-temperature reaction products, resulting in the formation of small molecular products.

Filling the gap: Cloze probability and sentence constraint norms for 807 European Portuguese sentences

Sentence processing is affected by the sentence context and word expectancy. To investigate sentence comprehension experimentally, it is useful to have sentence completion norms with both context constraint and word expectancy measures. In this study, two experiments were conducted to collect norms for completion of 807 European Portuguese sentences. Context constraint was measured through type-token ratio and proportion idiosyncratic responses, while word expectancy was assessed by cloze probability. Besides establishing norms for a large sample of sentences, the study investigated the impact of the production procedure and method of analysis. In Experiment 1, a single-production procedure was used, i.e., participants completed each sentence fragment with only a single response, whereas in Experiment 2, a multiple-production procedure was used, i.e., participants have to provide up to three completion words for each sentence fragment. In Experiment 2, the analyses were obtained using two distinct methods: first-response analysis and combined-response analysis. The results showed that cloze and context measures are comparable between production paradigms and that the results from both analysis methods were correlated. The advantages of each production procedure and analysis method are discussed.

Suppression effect of bionic guide vanes with different parameters on the hump characteristics of pump-turbines based on entropy production theory

Based on the principles of bionics, this study drew on the protuberances of the leading edge of a humped whale flipper, designed different bionic protuberances applied to stay-guide vanes, and conducted three-dimensional numerical simulation research on the pump-turbine pump mode with an opening of 28.5 mm. The Euler theory and hydraulic loss entropy production analysis method was used to compare and analyze the pump characteristics of different schemes. The results showed that the bionic protuberances could effectively destroy the coherent structure of turbulence in the flow field, thereby improving the internal flow regime of the runner channel and significantly reducing flow separation. The protuberances can reduce the flow angle of the runner outlet by 5%–10%, resulting in an increase in the Euler head by 3%, which significantly increases the hump margin. In addition, bionic protuberances can effectively improve the flow regime in the stay-guide vanes and runner and weaken the flow separation, thereby avoiding the generation of a high local entropy production region and reducing the hydraulic loss by 4%. Therefore, protuberances can effectively improve the hump characteristics.

Comparative Study of Densitometry and Videodensitometry for Quantitating the Active Pharmaceutical Ingredients Using Thin Layer Chromatography – Systematic Review

Background: Chromatography is one of the analytical techniques widely used for the quality control process in the pharmaceutical industry. One of the analytical methods used in drug analysis is Thin Layer Chromatography (TLC). The analysis process of TLC can be performed using densitometry (scanner) or videodensitometry (videoscan). The principal analysis of densitometry (scanner) is based on the density measured from each spot on the TLC plate using a specific wavelength range, and videodensitometry (videoscan) is performed by taking pictures of the plate using a Visualizer at a specific wavelength. Objective: This review article discusses the application of densitometry and videodensitometry methods for quantitative analysis of pharmaceutical products. Methods: This study was conducted using a systematic review method using the PRISMA statement from January to April 2023. Four databases were searched: PubMed, ScienceDirect, Scopus, and Google Scholar with inclusion criteria: studies on thin layer chromatography analysis using densitometry and videodensitometry. Results: Based on the ten articles in this study, it is known that the active ingredient concentrations in pharmaceutical products can be determined using densitometry and videodensitometry. The statistical analysis results show no significant difference between the two methods' chemical concentrations of active ingredients in pharmaceutical products. Conclusion: TLC densitometry and videodensitometry is a valid methods analysis that can be used for quantitating the active pharmaceutical ingredient concentration in finished pharmaceutical products.

Online analysis method for pyrolysis products with large volatility difference at high temperature and pressure: Pyrolysis kinetics of supercritical pressure n-decane

Pyrolysis is widely applied in industrial fields including waste-to-energy conversion and hypersonic-vehicle cooling technology. Traditional offline analysis methods for fluid products based on cooling, depressurization, and separation processes often impart measurement uncertainties. Here, we propose a novel online analysis method for fluid pyrolysis products with significant volatility differences. High-frequency sampling based on instant cooling–flashing was used to avoid gas–liquid separation, where the fluid mixture is directly transported into an online-GC system as a vapor through a preheated vacuum tube. The method reliability was evaluated experimentally. Pyrolysis of supercritical-pressure n-decane (3–7 MPa) in a mini-tubular reactor was analyzed using both the proposed online method and an offline method. The gas yield measured using the offline method is significantly lower than that measured online due to the dissolution and volatilization loss of gaseous products during gas–liquid separation. The mass fraction of C3–C4 products measured using the offline method was 40–80% less than the online results. The maximum deviation in the mass fraction of the main products obtained offline was reduced to 20–25% after dissolution-loss correction. The kinetic constants of n-decane pyrolysis were determined based on product-yield data, and the calculated residence time was experimentally verified using particle image statistics. The proposed model was implemented in a computational fluid dynamics model. The deviation between the predicted conversion and experimental results was below 11%, while the deviations of the predicted mass fraction of typical products was significantly higher based on the offline model than the online model.

Applications of imaging systems for the assessment of quality characteristics of bread and other baked goods: A review.

One of the most widely researched topics in the food industry is bread quality analysis. Different techniques have been developed to assess the quality characteristics of bakery products. However, in the last few decades, the advancement in sensor and computational technologies has increased the use of computer vision to analyze food quality (e.g., bakery products). Despite a large number of publications on the application of imaging methods in the bakery industry, comprehensive reviews detailing the use of conventional analytical techniques and imaging methods for the quality analysis of baked goods are limited. Therefore, this review aims to critically analyze the conventional methods and explore the potential of imaging techniques for the quality assessment of baked products. This review provides an in-depth assessment of the different conventional techniques used for the quality analysis of baked goods which include methods to record the physical characteristics of bread and analyze its quality, sensory-based methods, nutritional-based methods, and the use of dough rheological data for end-product quality prediction. Furthermore, an overview of the image processing stages is presented herein. We also discuss, comprehensively, the applications of imaging techniques for assessing the quality of bread and other baked goods. These applications include studying and predicting baked goods' quality characteristics (color, texture, size, and shape) and classifying them based on these features. The limitations of both conventional techniques (e.g., destructive, laborious, error-prone, and expensive) and imaging methods (e.g., illumination, humidity, and noise) and the future direction of the use of imaging methods for quality analysis of bakery products are discussed.

Bioconversion of Phytosterols into Androstenedione by Mycolicibacterium.

The chapter describes the bioconversion of phytosterols into androstenedione (AD) by Mycolicibacterium spp. in shake flasks and fermenters, as well as LC-MS-based methods for analysis of phytosterols and steroid products. Phytosterols are derived as by-products of vegetable oil refining and manufacture of wood pulp. They contain the same four-ring nucleus as steroids and may be converted to high-value steroids by removing the sidechain at C17 and minor changes at other sites in the ring structure. Many bacteria, including Mycolicibacterium spp., can degrade phytosterols. Mutants of Mycolicibacterium spp. unable of ring cleavage can, when growing on phytosterols, accumulate the steroid intermediates androstenedione (AD) and androstadienedione (ADD). The practical challenge with microbial conversion of phytosterols to steroids is that both the substrate and the product are virtually insoluble in water. In addition, some steroids, notably ADD, may be toxic for the cells. Two main strategies have been employed to overcome this challenge: the use of two-phase systems and the addition of chemically modified cyclodextrins. The latter method is used here. Defined cultivation and bioconversion media for both shake flask and fermenter are given, as well as hints how to minimize the practical problems due to the water-insoluble phytosterol. Sampling, sample extraction, and quantification of substrates and products using LC-MS analysis are described.

Entropy production analysis of a radial inflow turbine with variable inlet guide vane for ORC application

The fluctuation of heat source conditions leads to the off-design operation and efficiency reduction of the radial inflow turbine (RIT). The adjustment of the outlet angle of inlet guide vane (IGV) is an important way to improve the turbine performance under off-design conditions. Since the energy dissipation caused by friction and flow separation is the main reason for the reduction of RIT efficiency, the entropy production analysis method is used to diagnose the location with high local energy loss in the RIT and evaluate its total energy loss under different working conditions in this paper. Firstly, an appropriate outlet angle of the IGV is determined according to the inlet pressure and outlet pressure of the RIT in organic Rankine cycle (ORC). Then, the effects of inlet pressure and outlet pressure on its energy loss are studied. The results indicate that the average entropy production rate (EPR) of the rotor in the RIT is the highest, which is mainly from the tip clearance and the inlet region. More than 70% of total entropy production of the turbine comes from the rotor, followed by the diffuser. The turbine can achieve lower total entropy production at higher outlet pressure or lower inlet pressure. Compared with a fixed IGV, the turbine with variable IGV can achieve higher turbine efficiency and output power under off-design conditions. The maximum increase in the efficiency and output power of the turbine with variable IGV under different inlet pressures is 3.8% and 12.9%, respectively.

An Investigation of the Reaction Mechanism of the Direct Electrochemical Propylene Oxidation to Propylene Oxide with Electrochemical Mass Spectroscopy

Propylene oxide is a high-value precursor in the chemical industry with a large variety of applications and a market growing 4-5% annually. Currently, more than 10% of the propylene is used for the production of propylene oxide. The traditional methods for producing propylene oxide are chlorohydrin and hydroperoxide methods. These methods are costly, environmentally pollutant, and inefficient with a high proportion of by-products[1]. Renewable energy sourced direct electrocatalytic propylene oxidation to propylene oxide stands out as a way to replace the traditional methods and overcome the mentioned disadvantages. However, there has been a very limited number of studies about this topic in the last few decades starting from the 1960s. The experimental systems in these studies were significantly different from each other in terms of electrochemical cells and test methods, temperature, reactants, catalysts, etc[2–7]. Additionally, due to the limitation of available characterization and product detection methods the conclusions could not be well established. The majority of the performed studies suffered from difficulties in detecting and accurately quantifying propylene oxide due to its high volatility and hydrolysis to propylene glycol. Likewise, recent results from Winiwarter et al. revealed that there is propylene glycol formation on Pd catalysts at high potentials above 1.0 V vs. RHE in 0.1 M HClO4 and the selectivity towards dehydrogenation products decreases however, due to the lack of sensitive and fast product analysis method they could not quantify the propylene oxide even though they could detect it [8]. Moreover, there is only a limited number of studies investigating the reaction mechanism for electrochemical propylene oxidation towards propylene oxide. The theoretical study done by Li et al. proposed propylene oxide formation on PdO2(110) at 1.23 V vs RHE where the oxygen vacancies formed on the catalyst therefore they suggest that propylene reacts with lattice oxygen. Additionally, they suggest the competing reaction pathway to epoxidation as dehydrogenation of –CH3 results in acrolein, CO, and CO2[9]. Contrarily, Otsuka suggested a tentative Langmuir-Hinselwood mechanism for electrochemical propylene oxidation to propylene oxide[10]. In conclusion, the reaction mechanism for electrochemical propylene epoxidation on Pd is still not well understood. Therefore, we focused on discovering the reaction mechanism since it is crucial to design a rational catalyst. In this work, we are investigating in-situ electrocatalytic propylene oxidation to propylene oxide on different catalysts, starting from Pd. The unique electrochemical mass spectroscopy device that we are using enables in-situ detection and quantification of propylene oxide and also competing dehydrogenation pathway products acrolein and CO2 proposed by the theoretical study of Li et al.[9]. In addition to that, this device enables us to detect these products with great time resolution, so we are able to see the differences in product distribution very quickly when we change the applied potential. With these measurements, we offer an insight into the reaction pathway towards the electrochemical formation of propylene oxide and extend our investigations to other catalysts besides Pd. We believe that this study will help to understand the reaction mechanism for different catalysts leading to a great impact on rational catalyst design for electrochemical propylene oxidation to propylene oxide. [1] T.A. Nijhuis, M. Makkee, J.A. Moulijn, B.M. Weckhuysen, Ind. Eng. Chem. Res., 45, (2006), doi:10.1021/ie0513090. [2] J.O.M. Bockris, H. Wroblowa, E. Gileadi, B.J. Piersma, Trans. Faraday Soc., 61, (1965), doi:10.1039/tf9656102531. [3] T.C. Chou, J.C. Chang, Chem. Eng. Sci., 35, (1980). [4] K. Scott, C. Odouza, W. Hui, Chem. Eng. Sci., 47, (1992),doi:10.1016/0009-2509(92)87158-M. [5] V.M. Schmidt, E. Pastor, J. Electroanal. Chem., 401, (1996), doi:10.1016/0022-0728(95)04299-7. [6] H. Wise, L.L. Holbrook, J. Catal., 298, (1975). [7] G.R. Stafford, Electrochim. Acta., 32, (1987),doi:10.1016/0013-4686(87)80024-5. [8] A. Winiwarter, L. Silvioli, S.B. Scott, K. Enemark-Rasmussen, M. Sariç, D.B. Trimarco, P.C.K. Vesborg, P.G. Moses, I.E.L. Stephens, B. Seger, J. Rossmeisl, I. Chorkendorff, Energy Environ. Sci., 12, (2019), doi:10.1039/c8ee03426e. [9] H. Li, C.S. Abraham, M. Anand, A. Cao, J.K. Nørskov, J. Phys. Chem. Lett., 13, (2022), doi:10.1021/acs.jpclett.2c00257. [10] K. Otsuka, T. Ushiyama, I. Yamanaka, K. Ebitani, J. Catal., 157, (1995),doi:10.1006/jcat.1995.1310.

Productivity Prediction and Analysis Method of Large Trailing Suction Hopper Dredger Based on Construction Big Data

Trailing suction hopper dredgers (TSHD) are the most widely used type of dredgers in dredging engineering construction. Accurate and efficient productivity prediction of dredgers is of great significance for controlling dredging costs and optimizing dredging operations. Based on machine learning and artificial intelligence, this paper proposes a feature selection method based on the Lasso-Maximum Information Coefficient (MIC), uses methods such as Savitzky-Golay (S-G) filtering for data preprocessing, and then selects different models for prediction. To avoid the limitations of a single model, we assign weights according to the predicted goodness of fit of each model and obtain a weight combination model (WCM) with better generalization performance. By comparing multiple error metrics, we find that the optimization effect is obvious. The method effectively predicts the construction productivity of the TSHD and can provide meaningful guidance for the construction control of the TSHD, which has important engineering significance.

3D ergonomics-based motion-level productivity analysis for intelligent manufacturing in industrialized construction

In industrialized construction, accurate estimations of labour productivity and associated cycle times of repetitive operations are crucial for reliable production planning and scheduling. However, the reliability of the standardized productivity and cycle time analyses is hindered by their dependence on various factors that change with the increasing complexity of the working environment, as well as by inherent challenges involved in acquiring accurate measurements. Thus, this study proposes an automated 3D ergonomics-based motion-level productivity analysis method for intelligent manufacturing in industrialized construction that combines an existing predetermined motion–time system with ergonomic risk assessments and 3D modelling techniques. The actual and simulated cycle times and ergonomic risks of preliminary cases in the experiment are analyzed to demonstrate the feasibility and reliability of the proposed method. The proposed method can be implemented to improve occupational safety, increase the reliability of planning and scheduling, and boost the overall productivity of industrialized construction.

Cavitation Suppression and Design Optimization in a Cryogenic Liquid Turbine Expander Based on Thermodynamic Cavitation and Entropy Production Analysis

Abstract Cryogenic liquid turbine expanders have emerged quite recently as a replacement of J–T valve for enhancing energy efficiency of industrial systems, such as air separation units (ASUs) and Supercritical Compressed Air Energy Storage systems. In the liquid turbine expander, the rotating impeller-induced swirling flow and cavitation are essentially significant and intensive, which requests some in-depth work toward a thorough understanding flow physics and then effective attenuation. This study aims at effectively mitigating the swirling flow and cavitation. The entropy production analysis method (EPAM) is proposed to characterize the swirling flow and cavitation. It is then incorporated with the improved cavitation and turbulence models and validated through the simulation of the Hord's liquid nitrogen hydrofoil. To mitigate the swirling flow and subsequent cavitation, the design optimization method is developed, in which a novel optimization objective function is constituted by incorporating the local entropy production rate and vapor volume fraction to capture the mechanical energy dissipation and cryogenic cavitating flow physics; the non-uniform relational B-Splines and free form deformation (NURBS–FFD) parametric method is used to facilitate a flexible variation in impeller blade and diffuser vane geometries. It is solved within cfx frame by means of the particle swarm optimization (PSO) algorithm coupling the Kriging-based adaptive surrogate model. With the design optimization, the impeller and vaned diffuser tube geometries are collaboratively fine-tuned, and the mechanical energy dissipation and cavitating flow across both the impeller and vaned diffuser tube is effectively mitigated.