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Purpose – The aim of this study is to determine the differences in the antimicrobial activity of katuk leaf (Sauropus androgynus (L.) Merr) against Escherichia coli.

Design/Methodology/Approach – The method used in this study was experimental posttest using a control group design. Analysis of the effect of katuk leaf was performed in the dilution method with 20%, 40%, 60%, 80%, and 100% concentration. The data were analyzed using one-way ANOVA test (α = 0.05) and was then tested using the least significant difference (LSD) test.

Findings – Bacterial colony counting that used total plant count found the average of E. coli amount at 20% of concentration (526.820 CFU/ml), 40% of concentration (449.380 CFU/ml), concentration of 60% (255.710 CFU/ml), concentration of 80% (194.110 CFU/ml), and at concentration 100% (168.600 CFU/ml). This study concluded that the katuk leaf extract at 20%, 40%, 60%, 80%, and 100% of concentration had antimicroba effect with significant influence. The 100% of concentration had the most significant effect compared with the other concentrations.

Research Limitations/Implications – Katuk leaf could be used as one of the alternative herbal choices that has a compound antimicrobial effect.

Originality/Value – This study increases the theoretical understanding of the difference of antimicrobial effectivity of katuk leaf extract (S. Androgynus (L.) Merr.) concentration against E. coli

The purpose of this study is to improve the performance of hollow fiber membrane and improve the separation efficiency.

By establishing a mathematical model of hollow fiber membrane gas separation, the influences of parameters such as pressure difference between the inside and outside of the filament, initial oxygen concentration of intake air, intake air flow rate and back pressure outside the filament on the polarization coefficient were analyzed, so as to explore the degree of influence of operating parameters on the concentration polarization, and put forward a technical scheme to reduce the concentration polarization.

Factors such as pressure difference between the inside and outside of the filament, initial oxygen concentration of intake air, intake air flow rate and back pressure outside the filament have a certain effect on the polarization coefficient. Among them, the polarization coefficient is positively correlated with pressure difference inside and outside the filament, initial oxygen concentration of intake air and back pressure outside the filament, and is negatively correlated with intake air flow.

Negative pressure suction on the permeation side can be used to increase the membrane permeation flow rate and reduce the concentration polarization.

The influence of concentration polarization on membrane performance is reduced by controlling various factors.

The present study aims at shedding some light on the serious effect of insecure pesticides to the surface ozone as a secondary pollutant resulting from some photochemical reactions during the sunny days. The temporal variation in O₃ concentrations due to pesticide spray, the corresponding temperature and relative humidity have been monitored and discussed. The air quality index (AQI) for the maximum concentrations of O₃ within each day of study has also been deduced. The obtained results illustrated that O₃ concentrations had been increased after pesticide spray with different values from hour to hour and then began to decay after one day or more according to its concentrations. The second day had the highest concentrations of the O₃ including the maximum concentration, which was recorded at hour 14 local time. Furthermore, most of AQI values were restricted between harmful and very harmful index during the second days and only the third day of the first experiment. Moreover, temperature and relative humidity have significantly influenced ozone concentrations with positive and negative correlation coefficients, respectively.

The purpose of this research is to study the effect of softener treatment on plain jersey fabrics with properties made of cotton and spandex yarn.

Samples with 100 percent cotton yarns, spandex yarns in alternating courses (half plating) and spandex yarns in every courses (full plating) were produced on a circular knitting machine where the two latter cases were produced at five different levels of spandex extension. After the dyeing process, fabrics were treated with fabric softener using two softener types (cationic and silicon) and all type two concentrations (3 percent, 6 percent) to evaluate the most appropriate softener type and concentration on fabric friction force, sewing needle penetration force and weight loss percent under different levels of spandex extension.

Results showed that silicon softener treatment results in high decreases in fabric sewing needle penetrating force, friction force and while treatment with cationic softener results in high decreases in weight loss percent for 100 percent cotton, half and full plating fabrics.

There is a growing need to study the effect of softeners when spandex yarns are used in the production of knitted fabric which results in high increase of stitch density. This research compares the effects of two different softener types at different concentrations on the properties of both plain jersey fabric produced from 100 percent cotton yarns and from cotton/spandex yarns with different stitch density.

Determining the variation law of the oxygen concentration in the ullage space of the fuel tank is the key to the design of the inert system. Among various factors affecting the oxygen concentration in the ullage space of the fuel tank, the temperature difference between day and night shows particular importance while relevant analysis and calculation are scarce.

This study establishes a theoretical simulation model of the central wing fuel tank of an aircraft according to the relevant provisions of day-night temperature variation in FAR25 airworthiness regulations, verifies the model with the existing experimental data and discusses the corresponding relationship between the oxygen concentration in the ullage space of the fuel tank and the day-night temperature difference. The influence of day and night temperature difference, fuel type, fuel load rate, initial oxygen concentration, dissolved oxygen evolution and other factors on the oxygen concentration in the ullage space of the fuel tank were analyzed, and the limit of initial oxygen concentration of the fuel tank before the shutdown at night meeting the requirements of the airworthiness provisions was proposed.

The results show that the temperature difference between day and night, fuel load rate, initial oxygen concentration and other factors have different effects on the oxygen concentration in the ullage space of fuel tank. The initial oxygen concentration limit before shutdown shall be 2% below the 12% oxygen concentration stipulated by FAA.

The research results in this paper will be of good reference value to the design of the inert system and the calculation of the flammability exposure evaluation time. This paper aims to be good reference of the design of the inert system and the calculation of the flammability exposure evaluation time.

The research results of this paper can provide practical guidance for the current civil airworthiness certification work.

This study aims to investigate the corrosion behavior of Cu-containing 3Ni steel in simulated marine environments and to provide basic guidance for improving the corrosion resistance of marine high-strength steels.

The corrosion properties of Cu-containing 3Ni steel were evaluated in five different NaCl concentrations by alternating wet and dry cycling method. The corrosion behavior was investigated by electrochemical impedance spectroscopy, scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The mechanism of the influence of Cl ion concentrations on the corrosion behavior of Cu-containing 3Ni steel in marine environments was analyzed.

The results showed that the corrosion resistance of Cu-containing 3Ni steel decreased with NaCl concentration increasing. With the increase of NaCl concentration, the number of FeOOH particles decreased and their size increased, resulting in an increase in the porosity and a decrease in the density of corrosion products. High NaCl concentration could inhibit the formation of NiFe₂O₄ and disrupt the electronegativity of the inner film of corrosion products, which further weakened the enrichment of Ni and Cu, and enhanced the permeability of Cl ions.

The influence of NaCl concentrations on the corrosion behavior of Cu-containing 3Ni steel was systematically studied and the influence laws of corrosion behavior were obtained in this paper, providing basic data for the optimal design of Cu-containing 3Ni steels.

This study aims to examine the performance outcomes of a store’s ownership concentration within a multi-unit franchise (MUF) network, emphasizing the nuanced effects under varying competitive conditions.

This study conducted a comprehensive analysis of all stores within the McDonald’s chain over an eight-year span. The research methodology incorporated a review of over 11 million customer evaluations to discern patterns in customer satisfaction and sales growth in relation to the store’s ownership concentration.

Stores with a pronounced ownership concentration showcased enhanced outcomes in both customer satisfaction and sales growth. However, the magnitude of these effects was moderated by the nature of competitive conditions, specifically focal market competition, non-focal market competition and legal safeguards.

The study’s concentration on McDonald’s stores introduces a specificity that might limit the universal applicability of the findings to all franchise models or sectors. Additionally, the emphasis on the store level of analysis potentially overlooks broader systemic factors.

For managers and franchise owners, understanding the nuanced roles of ownership concentration can provide strategic insights. Recognizing how different competitive conditions can moderate the effects of ownership concentration can help in making informed decisions about power dynamics and competitive positioning.

A store’s ownership concentration can have broader societal ramifications, potentially shaping consumer perceptions, community engagement and overall market health. As an owner’s stores concentrate spatially, they can contribute to a healthier market ecosystem, benefitting consumers and communities alike.

While the vertical power between the franchisor and franchisee owners have been studied, this study extends the discourse to power between MUF owners. This study provides novel insights by showing customer centric and firm centric performance outcomes of ownership concentration.

This study aims to investigate the relationship between inventory flexibility, digital transformation, supply chain concentration, and productivity in the context of Chinese manufacturing enterprises.

Empirical analysis was conducted using data from listed Chinese manufacturing firms spanning from 2013 to 2022. The study employs a moderated model to examine how digital transformation influences the connection between inventory flexibility and productivity. Additionally, a moderated moderation model is utilized to explore the role of supply chain concentration in moderating the relationship among inventory flexibility, digital transformation, and productivity.

The study reveals a significant positive correlation between inventory flexibility and productivity, underlining the importance of flexible inventory management. Digital transformation moderates this relationship, with digital transformation enhancing the impact of inventory flexibility on productivity. Supplier and customer concentration also positively moderate this connection, suggesting a complementary relationship with digital transformation.

These findings offer valuable insights for managers and policymakers, emphasizing the need for a flexible approach to inventory management that considers the evolving digital landscape and supply chain dynamics.

This study contributes to the literature by providing empirical evidence of the nuanced relationship between inventory flexibility, digital transformation, supply chain concentration, and productivity in Chinese manufacturing enterprises. It underscores the importance of integrating digital transformation and supply chain concentration initiatives with flexible inventory management to optimize productivity in the business landscape.

Digitalization and supply chain collaboration are central to the successful servitization of manufacturing firms. However, how digitalization interacts with supply chain structure to affect servitization decisions in manufacturing firms has been understudied. In this study, we bridge resource dependence theory (RDT) and information processing theory (IPT) to examine how supply chain concentration interacts with digitalization to affect servitization decisions in manufacturing firms.

We tested the hypotheses using a panel dataset of 1,261 publicly listed machinery manufacturing firms in China. We addressed the endogeneity concerns using the control function approach and conducted multiple tests to ensure the robustness of the results.

We find that both supplier and customer concentration are negatively related to servitization, indicating that concentrated supplier and customer bases are hindrances to manufacturing servitization. Digitalization weakens the negative impact of customer concentration on servitization, but it strengthens the negative impact of supplier concentration on servitization.

The findings extend our understanding of supply chain structure and digitalization as determinants of servitization. This research also offers a nuanced view of how digitalization mitigates the negative impacts of supply chain concentration.