Heterogeneous Production Research Articles

Informal pricing in formal fish markets: Evidence from the Solomon Islands

How are fish prices determined in the largest formal market in the Solomon Islands? The Honiara Central Market is the country’s primary fresh produce market, serving as an important conduit between rural food producers and urban consumers. One distinctive characteristic of this market is that despite a diverse range of reef fish species being available, all reef fish are traded nominally as homogeneous goods with no price differentiation. Using transaction-level data collected from the market, we show the prevalence of informal pricing, wherein the unit price of fish is implicitly differentiated based on fish species groups, quality, and buyers’ attributes. This result aligns with our expectation that diverse species groups and qualities are traded in a competitive environment with many vendors and buyers, where reef fish are indeed traded as heterogeneous products. Although fish provide a vital source of food and income for Pacific Island countries, the pricing of this vital natural resource is poorly understood. Our study provides new insights into how fish prices are determined in a formal market within the context of small island developing states.

Joint optimization of product design and manufacturing inventory in a C2M supply chain

Motivated by the prevalence of Consumer-to-Manufacturer (C2M) programs in retail platforms, this study considers a Vendor Managed Inventory (VMI) supply chain system, consisting of a retail platform and a manufacturer, which designs and sells a new product to a market of customers. Particularly, the manufacturer’s design of the product’s attributes would affect the conversion rate of the customers who click the web links to the product, and customer demand for the product eventually. The manufacturer jointly plans the product design and inventory control in this model. By exploring the model, we demonstrate that the manufacturer makes inventory decisions following a modified base-stock policy dependent on the conversion rate, and adjusts the product design as the inventory cost rate increases. Furthermore, we find the manufacturer’s separate plan of product design and inventory control harms the manufacturer but can benefit the retail platform and the entire supply chain. This finding can explain why the manufacturer’s separate plan is a widely observed phenomenon in practical C2M programs. We further propose a hybrid contracting scheme, which combines quantity discount and cost sharing contracts, to coordinate the supply chain system. Two-fold extensions of the main model, heterogeneous customer valuation and dynamic product design, have also been considered.

ICT, heterogeneous labor structure and productivity of producer service enterprises: evidence from China

PurposeThis paper explores the impact of information and communications technology (ICT) on the productivity rates of producer service enterprises and its mechanisms.Design/methodology/approachThe core dataset used in this paper is the World Bank’s 2012 China Enterprise Survey. The data on enterprises provided by the World Bank has its unique advantages. First, the questionnaire provides a detailed record of enterprises’ ICT investment and usage. Second, it provides a diversified description of the enterprises’ current labor structures in terms of education, skills and employment latitudes. Building on this dataset, this paper adopts quantitative methods, including the fixed effect model and instrumental variable approach for the study.FindingsOur research shows that ICT application boosts the productivity of producer service enterprises. Employees with a high education background, proficient skills and non-lifelong contracts complement the application of ICT. Heterogeneity analysis reveals significant productivity and a complementary effect of ICT on labor structure in regions with well-developed markets, knowledge-intensive industries and enterprises with a relatively larger scale of operation.Originality/valueIn the context of digital globalization, the rational use of ICT to lead the high-quality development of the service industry is of great significance in achieving structural transformation.

Industrial robots and export product quality: evidence from China

ABSTRACT In this study, we first construct a theoretical framework for a heterogeneous product quality model to analyse how robot adoption affects international trade through quality upgrading. Then, we use micro-level data from Chinese Customs Trade Statistics and the Annual Survey of Industrial Firms to examine the heterogeneous effects of industrial robots on export product quality. Both theoretical analysis and empirical research show that industrial robots promote export product quality upgrading through effectively improving firms’ total factor productivity and reducing marginal production costs. Moreover, industrial robots have different effects on firms based on product types, ownership properties, and factor intensity. The results show that the effects of industrial robots on export product quality are stronger for homogeneous products, foreign and private enterprises for homogeneous products, foreign and private enterprises, and labour-intensive industries. These findings align with the literature on the wide-ranging impact of industrial robots, while offering a distinct opportunity to empirically investigate enterprises’ diverse responses to a uniform general-purpose technology. This study also diverges from previous research by examining a previously overlooked dimension: productivity-boosting and marginal cost-reducing effects.

The Minimotor Ltd: Pioneering digital transformation in production and operations

This teaching case examines the complexities encountered by a global industrial company undergoing digital transformation, particularly due to its heterogeneous production landscape. It highlights the critical factors for effectively orchestrating digital transformation initiatives and utilizing the scalability of technological applications. This industry example is relevant for delegates, students and practitioners aiming to implement maturity models and to realize the digital transformation within the context of Industry 4.0.

Balancing heterogeneous assembly line with multi-skilled human-robot collaboration via Adaptive cooperative co-evolutionary algorithm

In human-centred manufacturing, deploying collaborative robots (cobots) is recognized as a promising strategy to enhance the inclusiveness and resilience of production systems. Despite notable progress, current production scheduling methods for human-robot collaboration (HRC) still fail to adequately accommodate workforce heterogeneity, significantly reducing their adoption and implementation. To address this gap, we introduce a novel model for the Assembly Line Worker Integration and Balancing Problem considering Multi-skilled Human-Robot Collaboration (ALWIBP-mHRC). This model aims to optimize task scheduling between semi-skilled workers and cobots, aiming to maximize productivity and minimize costs. It features a multi-skilled human-robot collaboration (mHRC) task assignment scheme that selects the optimal assembly/collaboration mode from seven scenarios, based on specific task requirements and resource-skill availability, thus maximizing resource-skill complementarity. To tackle the complexities of this problem, we propose an adaptive multi-objective cooperative co-evolutionary algorithm (a-MOCC) that incorporates a sub-problem decomposition and decoding framework tailored for ALWIBP-mHRC, enhanced by an adaptive evolutionary strategy based on Q-learning (Q-Coevolution). Experimental tests demonstrate the superior performance of the proposed method compared to other established metaheuristic algorithms across various instance sizes, underscoring its effectiveness in enhancing the productivity of production systems for semi-skilled workers. The findings are significant for investment decision-making and resource planning, as they highlight the strategic value of integrating cobots in large-scale heterogeneous workforce production. This work underscores the potential of cobots to mitigate skill gaps in assembly systems, laying the groundwork for future research and industrial strategies focused on enhancing productivity, inclusivity, and adaptability in a dynamically changing labour market.

Two-phase reactive transport modeling of heterogeneous gas production in a low- and intermediate-level radioactive waste repository

Deep geological disposal is a widely proposed approach for safe storage of low- and intermediate-level radioactive waste (L/ILW) for tens to hundreds of thousands of years. Although the use of cement materials will maintain a high pH environment that is favorable for radionuclide retention, slows down metal corrosion, and suppresses microbial activity, different gases may still be produced by chemical reactions, such as pH-dependent anoxic corrosion of metals, and the degradation of organic matter as well. Both reactions consume water and may lead to the formation of a free gas phase within and around the repository.In order to investigate the controlling factors of this gas production processes, a coupled reactive transport model of component-based two-phase flow in the OpenGeoSys framework is adopted here. Building on the previous work by Huang et al. (2021), this work extends the geometric configuration of the model from a single drum to the scale of a waste container (12 drums) in order to more realistically model the water and gas fluxes. The geochemical evolution of a container filled with cemented steel drums and surrounded by mortar and host rock is simulated in a two-dimensional setup over 500 years. The relative humidity in the pore space as measure of water availability determines the chemical reactivity.We have conducted a sensitivity study for the influence of mortar capillarity and permeability on gas production over time in the waste drums. As expected, the amount of gas produced within the first several years depends primarily on the initial water content within the waste drum and the amount of fast degradable waste stored in a drum. Later, this feedback system is forced into a new equilibrium, where the water transport has to match the water consumption rate at the waste package. Both, the mortar capillarity and permeability control the point in time when the equilibrium is reached and the subsequent rate of gas production.This study shows how reactive transport models are capable to help with the understanding of couplings between chemical and transport processes that control gas generation in L/ILW waste repositories, especially in barrier systems with different material properties. Future studies could benefit from more accurate parameterization of the chemical reactions, depending on the availability of new experimental data and/or more realistic process-based model approaches.

A circular economy approach to produce low-cost biodiesel using agro-industrial and packing wastes from Mexico: Valorization, homogeneous and heterogeneous reaction routes and product characterization

This manuscript describes a circular economy approach to produce low-cost biodiesel using Tetra Pak (TP) and Mexican biomass wastes. Lipids were extracted from non-edible biomass with hexane. Corozo seeds contained 53 wt% lipids, while remaining biomass had <5 wt%. Corozo seed oil was selected to produce biodiesel with both homogeneous and heterogeneous reaction systems. A heterogeneous catalyst was synthesized from TP and its performance was compared with KOH in homogeneous systems using corozo and soybean oils. The best reaction conditions were identified through the Signal/Noise ratio analysis. TP catalyst achieved biodiesel yields of 12.7–98.11 % (corozo) and 87.0–98.4 % (soybean), while KOH systems showed 7.2–96.3 % and 64.6–98.5 %, respectively. These reactive systems were endothermic and fit to pseudo-second order kinetic model. Activation energies for KOH-catalyzed systems were 86.89 (corozo) and 43.72 (soybean) kJ/mol, while TP-catalyzed systems showed 78.31 and 105.68 kJ/mol, respectively. TP catalyst reuse was tested, and the loss of catalytic activity was attributed to active sites poisoning. Biomass, catalysts, and reaction products were characterized (e.g., FTIR, ICP, XRD, EDX-SEM, WDXRF, XPS, basicity and nitrogen adsorption-desorption isotherms). The TP catalyst showed competitive performance with respect to KOH, contributing to a sustainable biodiesel production chain viable for commercial implementation in Mexico.

Exploiting phenotypic heterogeneity to improve production of glutathione by yeast

BackgroundGene expression noise (variation in gene expression among individual cells of a genetically uniform cell population) can result in heterogenous metabolite production by industrial microorganisms, with cultures containing both low- and high-producing cells. The presence of low-producing individuals may be a factor limiting the potential for high yields. This study tested the hypothesis that low-producing variants in yeast cell populations can be continuously counter-selected, to increase net production of glutathione (GSH) as an exemplar product.ResultsA counter-selection system was engineered in Saccharomyces cerevisiae based on the known feedback inhibition of gamma-glutamylcysteine synthetase (GSH1) gene expression, which is rate limiting for GSH synthesis: the GSH1 ORF and the counter-selectable marker GAP1 were expressed under control of the TEF1 and GSH-regulated GSH1 promoters, respectively. An 18% increase in the mean cellular GSH level was achieved in cultures of the engineered strain supplemented with D-histidine to counter-select cells with high GAP1 expression (i.e. low GSH-producing cells). The phenotype was non-heritable and did not arise from a generic response to D-histidine, unlike that with certain other test-constructs prepared with alternative markers.ConclusionsThe results corroborate that the system developed here improves GSH production by targeting low-producing cells. This supports the potential for exploiting end-product/promoter interactions to enrich high-producing cells in phenotypically heterogeneous populations, in order to improve metabolite production by yeast.

Fluid depth-dependent biofilm characteristics and their influence on sulfate-reducing bacteria-induced corrosion of carbon steel

This study investigates the response of biofilm characteristics to variations in fluid depth and their influence on the corrosion behavior of carbon steel (C1020) under low-flow fluid conditions, utilizing Desulfovibrio vulgaris. The experiments were conducted in an anaerobic chamber at 30 °C, utilizing modified Baar's medium as the testing medium. The findings reveal that fluid depth significantly impacts biofilm-corrosion product composite formation, with deeper depths promoting thicker and more heterogeneous biofilm-corrosion product layer compared to shallower depths, where a thinner and more uniform biofilm-corrosion product layer is observed. Moreover, the characteristics of initially attached biofilms was verified as the primary factor affecting subsequent corrosion behavior during prolonged exposure. Corrosion analysis reveals that greater fluid depth leads to increased weight loss (91 ± 13.2 mg/cm2) and deeper pit depths (540 ± 69 μm), surpassing those observed in shallower test media (21 ± 2.3 mg/cm2 and 105 ± 17 μm) after 28 days of exposure. The corrosion products within the biofilm were predominantly FeS and Fe3(PO4)2·8H2O. A direct relationship was observed between the thickness of this biofilm-corrosion product layer and the progression of pit depth, suggesting a strong correlation between carbon steel corrosion and biofilm development in limited fluid depths (e.g., 5–15 mm). Furthermore, a significant association between the deepest pits (average) and the number of sessile cells within the biofilm underscores the pivotal role of sessile cell numbers in carbon steel corrosion.

Club Convergence in Productivity among European Regions: Recent Evidence and Policy Implications

We use data on 155 NUTS regions, with the objective of i) generating TFP series over 1996-2018, and ii) testing for club-convergence. We also employ a logistic regression to identify the significant club-membership conditioning factors. We contribute to the literature on two main grounds. Firstly, we are the first to extract TFP series while applying a methodology that allows for heterogeneous production functions and accounts for cross-section dependence and nonstationarity. Secondly, we are the first to apply a TFP-club convergence analysis in the context of European regions over a large period of time that witnessed several shocks affecting the European integration. Our analysis reveals that: (i) most of the regions of the top TFP convergence clubs are located in the "old" EU-member states, with few regions situated in countries that joined the EU after 2004; (ii) several regions in the South are trailing with the risk of falling in a "productivity trap"; (iii) regions situated in new EU-member countries registered remarkable TFP growth rates; (iv) larger regional research and development resources, and higher employment in high-technology sectors are associated with a greater probability of being member of top-ranked TFP convergence clubs. Our findings suggest that the needs of the lagging regions should be prioritized in the agenda of the EU. In this respect, we suggest several recommendations.

High terephthalic acid purity: Effective polyethylene terephthalate degradation process based on pH regulation with dual-function hydrolase

Eco-friendly enzymatic-recycling has been widely utilized in tackling plastic pollution. However, the limited activity on the polyethylene terephthalate (PET) degradation product mono-hydroxyethyl terephthalate (MHET) leads to the formation of heterogeneous hydrolysis products, resulting in PET downcycling. Herein, by applying a dual-function PET hydrolase IsPETasePA with balanced PET and MHET degradation efficiency, an effective PET hydrolysis process was developed to enhance the terephthalic acid (TPA) product purity. Firstly, the impact of pH on the catalytic activity of IsPETasePA revealed that the pH reduction caused by TPA generation hindered the complete conversion of MHET to TPA. Further investigation of the catalytic mechanism showed that the pH-induced protonation of His208 in the catalytic triad destabilized the interaction between IsPETasePA and MHET. Thus, by introducing pH regulation strategy on the bifunctional IsPETasePA, the single-enzyme process could achieve high-purity TPA recovery (>99 %). Overall, this work ensured the high-quality PET enzymatic-recycling for effectively addressing plastic pollution.

A digital twin for operations management in manufacturing engineering-to-order environments

Engineering-to-order (ETO) companies satisfy a very demanding market, where each client specifies the type of product they require and actively participate in the design, selection of materials, and other activities. This converts the production processes of ETO companies into one-of-a-kind processes (OKP) type, where production planning and control (PPC) activities are extremely complex. The cause of this complexity is the little or no standardization between the different production cycles that must be executed, as each cycle is of the OKP type. In addition, Intra-logistics operations represent a key factor in ETO PPC, since each piece of work-in-process or sub-assembly can be extremely large, heavy or complicated of handling. Then, ETO systems involve heterogenous production and intra-logistics processes, where the associated information is fragmented and diverse. This hampers a streamline information processing and operations management. To overcome all these issues, a Digital Twin (DT) approach is proposed. The DT designed and developed here allows to integrate engineering and planning departments to be effectively integrated with the shop-floor and operations management in a smooth and effective manner. To solve interoperability and information access without overloading data-entry tasks novel information structures are designed, along with the logical processes that support them. These logical processes enable DT to generate autonomously intra-logistics operations orders from the engineering plans, fostering the system integration and agility. This DT is tested on a manufacturing ETO case study and shows its efficiency.

The Impact of Crop Year and Crop Density on the Production of Sunflower in Site-Specific Precision Farming in Hungary

Sunflower is considered a plant with extraordinary adaptability. However, the conditions of growing sunflower function as a limiting factor in its production. The hybrids used in production tolerate weather variability to a different level and utilise the nutrient and water resources of the soil, while the yield is also affected by the number of plants per hectare. In this study, the authors attempted to observe the environmental effects influencing sunflower cultivation, the heterogeneous productivity zones of the given production site and the correlation of the number of seeding plants used under various farm practices. The average rainfall of 2021 and the dry weather of 2022 created suitable conditions for examining the yearly weather effect. In the selected experimental areas, three distinguishable zones were defined in terms of productivity. In each productivity zone, three crop density steps were used in four replicates. Based on the performed comparative tests, the rainy year of 2021 resulted higher yield than the drier year of 2022 in the average- and high productivity zones, while in the low-productivity zone, higher yields were harvested under the drier conditions of 2022 than in the rainy year of 2021. In 2021, with the improvement in productivity, the obtained yield was also higher. However, in 2022, this clarity could not be demonstrated. In the zones with low productivity, identical yield results were observed in both weather conditions. Based on the examination of the obtained results, it was shown that the effect of weather conditions and the given number of plants have a smaller influence on the yield results of low-productivity zones, while these factors have a greater influence on the yields of high-productivity zones.

Heterogeneous products operation decisions of online dual-channel supply chain considering online reviews under different financing modes

This research examines the operation decisions of the online supply chain for heterogeneous products under different financing modes: e-commerce platform financing or bank financing, when manufacturers face funding constraints. Considering the manufacturer’s adoption of differentiated channel strategies when providing heterogeneous products is also considered, and combined with the impact of online reviews on consumer utility, an e-commerce platform online dual-channel financing model is constructed. The research findings are as follows: (i) when the effectiveness of online reviews differs within a certain range, the equilibrium solution exists. If the relative interest rates of the e-commerce platforms and bank change within a certain range, the same financing mode can bring mutual benefits to both the manufacturer and e-commerce platform, resulting in a “win–win” situation. (ii) If the interest rates under both financing modes are the same, the e-commerce platform financing mode has a higher wholesale price, but the difference in retail prices of distribution products depends on the costs difference between the two products, and at this point, the manufacturer will select e-commerce platform financing mode. (iii) At the optimal interest rate, when the cost of heterogeneous products is the same, the e-commerce platform consistently offers a more favorable interest rate compared to the bank’s optimal rate. when the e-commerce platform’s commission and the positive difference in product reviews is large, the manufacturer will choose e-commerce platform financing mode. Under the e-commerce platform financing mode, both the manufacturer and e-commerce platform are willing to provide lower retail prices to attract more consumers.

Porous polyselenoviologen with long-lived charge separated states and highly cyclic stability for heterogeneous photocatalytic reaction and hydrogen production

A highly stable heterogeneous photocatalyst, porous polyselenoviologen (POP-SeV2+), was successfully synthesized via SN2 reaction. Compared to the monomer, POP-SeV2+ exhibited strong visible-light absorption, enhanced electron acceptor property, and prolonged lifetime of radical cations. Simultaneously, the femtosecond transient absorption (fs-TA) illustrated that the formation of tetrahedral multi-cationic structure is conducive to the rapid generation of molecular excited states and extending the duration of charge-separated states. Due to its remarkable characteristics, the POP-SeV2+ was employed as a photocatalyst for visible-light-induced cross-dehydrogenative coupling (CDC) reactions with a highly efficient yield (82 %). Additionally, its utilization was further extended to the hydrogen generation, demonstrating remarkable outcomes such as a high rate of H2 generation (300 μmol·h−1·g−1), and an apparent quantum yield (0.13 %). Notably, POP-SeV2+ displayed great stability and reusability in the photocatalytic process, which can distinguish it from those soluble SeV2+-based photocatalysts. The catalytic efficiency of POP-SeV2+ remained virtually unaffected even after undergoing several recycling cycles, which not only achieved the complete heterogeneous photocatalysis of SeV2+-based systems for the first time but also provided a new strategy to improve the application effect of viologen derivatives in solar energy conversion and utilization.

DONN: leveraging heterogeneous outer products for CTR prediction

DONN: leveraging heterogeneous outer products for CTR prediction

Plug-and-play nucleic acid-mediated multimerization of biparatopic nanobodies for molecular imaging

In cancer molecular imaging, selecting binders with high specificity and affinity for biomarkers is paramount for achieving high-contrast imaging within clinical time frames. Nanobodies have emerged as potent candidates, surpassing antibodies in pre-clinical imaging due to their convenient production, rapid renal clearance, and deeper tissue penetration. Multimerization of nanobodies is a popular strategy to enhance their affinity and pharmacokinetics, however, traditional methods are laborious and may yield heterogeneous products. In this study, we employed a Holliday junction-like (HJ) nucleic acid-based scaffold to create homogeneous nanostructures with precise multivalent and multiparatopic nanobody displays. The plug-and-play assembly allowed the screening of several nanobody multimer configurations for the detection of the breast cancer biomarker, human epidermal growth factor receptor 2 (HER2). In vitro studies demonstrated significant improvements in binding avidity, particularly with the biparatopic construct exhibiting high sensitivity, surpassing that of traditional antibody-based cell binding. Furthermore, our HJ platform allowed for adaptation from fluorescence-based to nuclear imaging, as demonstrated in xenografted mice, thereby allowing for future in vivo applications. This work highlights the potential of nucleic acid-mediated multimerization to markedly enhance nanobody binding, by exploring synergistic combinations and offering versatility for both in vitro diagnostics and cancer molecular imaging with prospects for future theranostic applications.

Structure-Based Computational Scanning of Chemical Modification Sites in Biologics.

To address the challenges of short half-life, immunogenicity, and nonspecific distribution, chemical modifications of peptide and protein-based drugs have emerged as a versatile strategy for improving their therapeutic efficacy. One such modification involves the derivatization of peptides and proteins with fatty acids, which can protract their half-life, modify their biodistribution, and potentially enable targeted delivery to specific tissues or disease sites of interest. However, the present strategies for the synthesis of such synthetically modified biologics require numerous rounds of experimental testing and often yield unstable, inactive, or heterogeneous products. To address the inefficiencies in designing modified biologics, we developed a hybrid computational workflow that integrates RosettaMatch from the Rosetta suite of protein modeling tools with molecular dynamics (MD) simulations. This approach not only reduces the number of amino acid positions that need to be experimentally tested by targeting only the most promising candidates for modification but also expedites the design of chemically modified biologics with the desired properties, ensuring a rapid and cost-effective development cycle. Although we demonstrate the utility of our method on a peptide therapeutic, GLP-1, with different fatty acid derivatizations, this straightforward approach has the potential to streamline the design process of a diverse range of chemically modified therapeutics, enabling tailored enhancements to their pharmacokinetic properties.

Heterogeneous IL-9 Production by Circulating Skin-Tropic and Extracutaneous Memory T Cells in Atopic Dermatitis Patients.

Interleukin (IL)-9 is present in atopic dermatitis (AD) lesions and is considered to be mainly produced by skin-homing T cells expressing the cutaneous lymphocyte-associated antigen (CLA). However, its induction by AD-associated triggers remains unexplored. Circulating skin-tropic CLA+ and extracutaneous/systemic CLA- memory T cells cocultured with autologous lesional epidermal cells from AD patients were activated with house dust mite (HDM) and staphylococcal enterotoxin B (SEB). Levels of AD-related mediators in response to both stimuli were measured in supernatants, and the cytokine response was associated with different clinical characteristics. Both HDM and SEB triggered heterogeneous IL-9 production by CLA+ and CLA- T cells in a clinically homogenous group of AD patients, which enabled patient stratification into IL-9 producers and non-producers, with the former group exhibiting heightened HDM-specific and total IgE levels. Upon allergen exposure, IL-9 production depended on the contribution of epidermal cells and class II-mediated presentation; it was the greatest cytokine produced and correlated with HDM-specific IgE levels, whereas SEB mildly induced its release. This study demonstrates that both skin-tropic and extracutaneous memory T cells produce IL-9 and suggests that the degree of allergen sensitization reflects the varied IL-9 responses in vitro, which may allow for patient stratification in a clinically homogenous population.