Search Results (101)

This study aims to estimate the organic load of oily wastewater by using Chemical Oxygen Demand (COD) measurements, addressing the analytical challenges posed by the hydrophobic, nonpolar, and often emulsified nature of Fats, oil and grease (FOG). This study established a reproducible and practical methodology for measuring COD in wastewater containing FOG at a laboratory scale, utilizing the nonionic surfactant T80 as a solubilizing and emulsifying agent. Precise gravimetric methods were employed to measure the mass of T80 (indirectly from volume (100–1400 µL/L)) added, and its correlation with COD was established. A strong linear relationship (R² = 0.993–0.998) between T80 concentration and COD confirmed its stability and suitability as a calibration standard. Experiments with sunflower (1–4 mL/L) and rapeseed oils (1–3 mL/L) showed that COD increased linearly with oil concentration and stabilized after prolonged mixing (96–120 h), indicating complete emulsification and micellar equilibrium. Even under T80 overdose conditions, COD retained linearity (R² > 0.99), though absolute values were elevated due to excess surfactant oxidation. Temperature variation (5 and 20 °C) and mild heating of coconut fat (30–32 °C) showed no significant effect on COD reproducibility, indicating that mixing time and surfactant dosage are the dominant factors influencing measurement accuracy. Overall, the study establishes T80 as a reliable surfactant for solubilizing oily matrices, providing a consistent and repeatable approach for COD assessment of wastewater containing FOG. The proposed method offers a practical basis and a step towards environmental monitoring and process control in decentralized and industrial wastewater treatment systems. Full article

To the film thicknesses of grease-lubricated ball bearings, the viscosity of the base oil is considered in the Elastohydrodynamic Lubrication (EHL) equations. For very low speeds, the grease film thickness is much larger than the calculated base oil film thickness. Initially, the grease film thickness decreases with speed to a minimum value, followed by an increase, thus generating a “V-shape pattern”. To evidence this behavior of grease film in a ball bearing, the authors used the method of measuring electrical resistance. Using an oil with a viscosity close to a grease base oil viscosity, a relationship was obtained between the electrical resistance of the ball bearing and the average film thickness in the ball–race contacts. Based on this relationship, the variation in the grease film thickness was obtained by measuring electrical resistance at a bearing speed between 1 and 500 rpm for short running periods of 60 s. A “V-shape pattern” was evidenced with a minimum value of grease film thickness at around 10 rpm. Additionally, the electrical resistance methodology was considered, evidencing the good stability of the film thickness for long operation time at speeds between 200 rpm and 1500 rpm. After 8 running hours, minor fragmentation of the soap filaments was observed under the scanning electron microscope compared to the fresh grease structure, without affecting the thickness of the grease film. Full article

Thermodynamic free energy is used to elucidate the significance of energy dissipation-induced temperature rise on the performance, reliability, and durability of all systems, biological, chemical and physical. Transformation (a measure of reliability) and degradation (a measure of durability) are distinguished. The temperature rise mechanism is characterized by the microstructurothermal (MST) energy/entropy. A framework to quantify the contributions of the MST entropy to system transformation and degradation is introduced and demonstrated using diverse multi-physics systems: cardiovascular strain in humans, charge capacity of batteries, tribological wear of journal bearings, and shear strength of lubricating greases. Various levels of temperature-induced degradation are observed in the systems. Thermal degradation rate increases with process and energy dissipation rates. The benefits of active cooling on systems and materials are shown. This article is recommended to engineers, scientists, designers, medical doctors, and other system analysts for use in dissipation/degradation characterization and minimization. Full article

Rolling Bearings are crucial components for induction motors and generators in electric vehicles (EVs), as their performance considerably influences the system’s operational reliability and safety. However, the commercial greases used for bearing lubrication in EV motors pose a detrimental impact on the environment. In addition, they are ineffective in mitigating the effect of electric discharges on rolling surfaces leading to premature bearing failures. This study investigates the viability of a developed eco-friendly grease from palm olein as the base oil and glycerol monostearate as the thickener, enhanced with conductive multi-walled carbon nanotubes (MWCNTs) for EV motor bearings prone to electrical currents. Chemical–physical, tribological, and electrical tests were conducted on the developed grease samples without and with MWCNTs at 1 wt.%, 2 wt.%. and 3 wt.% concentrations and results were compared to lithium and sodium greases. Palm grease samples demonstrated a lower EDM voltage range reaching 1.0–2.2 V in case of 3 wt.% MWCNTs blends, indicating better electrical conductivity and protecting the bearing surfaces from electric-related faults. These findings were further confirmed using vibrations measurement and SEM-EDX analysis of the electrically worn bearings. Bearings lubricated with palm grease blends exhibited lower vibration levels. Palm grease with 2 wt.% MWCNTs reduced vibration amplitudes by 28.4% (vertical) and 32.3% (horizontal). Analysis of bearing damaged surfaces revealed enhanced damaged surface morphology for MWCNT-enhanced palm grease as compared to surface lubricated by commercial greases. The results of this work indicate that the proposed bio-grease is a promising candidate for future application in the field of next-generation electric mobility systems. Full article

Previous studies have shown that fats, oils, and greases (FOG) can be deoxygenated to fuel-like hydrocarbons over inexpensive alumina-supported Ni catalysts promoted with Cu or Fe to afford excellent yields of renewable diesel (RD). In this study, supports other than alumina—namely, SiO₂-Al₂O₃, Ce_0.8Pr_0.2O₂, and ZrO₂—were investigated to develop catalysts showing improved RD yields and resistance to coke-induced deactivation relative to Al₂O₃-supported catalysts. Results showed that catalysts supported on Ce_0.8Pr_0.2O₂ and ZrO₂ outperformed SiO₂-Al₂O₃-supported formulations, with 20%Ni-5%Fe/ZrO₂ affording a quantitative yield of diesel-like hydrocarbons. Notably, the abundance of weak acid sites varied considerably across the different supports, and a moderate concentration of these sites corresponded with the best results. Additionally, temperature-programmed reduction measurements revealed that Ni reduction is greatly dependent on both the identity of the promoter and catalyst support, which can also be invoked to explain catalyst performance since metallic Ni is identified as the likely active site for the deoxygenation reaction. It was also observed that Ce_0.8Pr_0.2O₂ provides high oxygen storage capacity and oxygen mobility/accessibility, which also improves catalyst activity. Full article

This study presents a machine learning approach for estimating the presence and extent of flange-face lubrication on a rail. It offers an alternative to the current empirical and subjective methods for lubrication assessment, in which track engineers’ periodic visual inspections are used to evaluate the condition of the rail. This alternative approach uses a laser-based optical sensing system developed by the Railway Technologies Laboratory (RTL) located at Virginia Tech in Blacksburg, VA, combined with a machine learning calibration model. The optical sensing system can capture the fluorescence emitted by the grease to identify its presence, while the machine learning model classifies the extent of grease present into four thickness indices (TIs), from 0 to 3, representing heavy (3), medium (2), light (1) and low/no (0) lubrication. Both laboratory and field tests are conducted, with the results demonstrating the ability of the system to differentiate lubrication levels and measure the presence or absence of grease and TI with an accuracy of 90%. Full article

The presence of oil slicks in the ocean presents significant environmental and regulatory challenges for offshore oil processing operations. During primary oil–water separation, produced water is discharged into the ocean, carrying residual oil, which is measured using the total oil and grease (TOG) method. The formation and spread of oil slicks are influenced by metoceanographic variables, including wind direction (WD), wind speed (WS), current direction (CD), current speed (CS), wind wave direction (WWD), and peak period (PP). In Brazil, regulatory limits impose sanctions on companies when oil slicks exceed 500 m in length, making accurate prediction of their occurrence and extent crucial for offshore operators. This study follows three main stages. First, the performance of five machine learning classification algorithms is evaluated, selecting the most efficient method based on performance metrics from a Brazilian company’s oil slick database. Second, the best-performing model is used to analyze the influence of metoceanographic variables and TOG levels on oil slick occurrence and detection probability. Finally, the third stage examines the extent of detected oil slicks to identify key contributing factors. The prediction results enhance decision-support frameworks, improving monitoring and mitigation strategies for offshore oil discharges. Full article

Ticks pose one of the key economic risks to the cattle industry globally, affecting productivity, health, and welfare. Over 80% of the cattle population around the globe is affected by tick infestation. Several tick control methods, including the use of chemical acaricides, herbal agents, and some complementary measures, like the use of old motor oil, disinfectant, pour-on, tick grease, pulling off, cutting, paraffin, and Jeyes fluid, have been used by farmers to alleviate the effects of hematophagous ticks. However, these strategies are often mistakenly employed and can harm animals. Likewise, these methods cannot be sustained because of their cost, environmental impact, flaws, and resistance. An abundantly available, cost-effective, environmentally friendly, and naturally occurring substance like fossil shell flour with no known side effects could present a sustainable solution. This review abridged the research and information on hematophagous tick control in South African cattle production using fossil shell flour. This is a systematic review of the published literature and catalogues. All available documented evidence on this topic was collated and synthesized through standardized methods of systematic review protocol. Different scientific studies and a few references from farmers’ magazines published from 1941 to 2022 were reviewed. Out of 120 research papers downloaded, 98 were included and analyzed directly or indirectly regarding hematophagous tick control in cattle production and the use of fossil shell flour among livestock farmers. The advancement in ectoparasite control through fossil shell flour is a novel concept that needs to be explored for the benefit of all livestock farmers, hence this review. Fossil shell flour has been shown to have good insecticidal effectiveness against insects of animal and agricultural importance. We hereby recommend the exploration of FSF as an alternative tick control measure to the currently used acaricides to which ticks have developed resistance. Full article

The demand for sustainable packaging has increased the interest in biopolymer coatings as alternatives to plastic-based barriers on paper and board. Alginate and chitosan offer promising barrier properties by improving gas barrier and grease resistance. However, their high viscosity at low solid contents presents challenges for uniform coatings, especially in possible future large-scale applications but also in existing research. This study evaluates spray coating, a non-conventional application method in the paper industry, to apply biopolymer coatings, an approach underexplored in previous studies. The effects of substrate surface energy and biopolymer surface tension on air permeability, grease resistance, and water vapor transmission were evaluated. Contact angle measurements showed that surface energy strongly influences the wetting behavior of these biopolymers, with hydrophilic substrates and lower-surface-energy liquids promoting better droplet spreading. This improved wetting resulted in better barrier performance at low application weights, further enhanced by surfactant addition. At higher application weights, surface energy had less impact on barrier properties. SEM imaging revealed drying defects at increased coat weights, affecting film integrity. These findings demonstrate the potential of spray coating as a scalable method for biopolymer application while highlighting the need for optimized drying conditions to enhance film uniformity and barrier performance. Full article

Volatile organic compounds (VOCs) are one of significant contributors to air pollution and have profound effects on human health and the environment. This study introduces a detailed analysis of VOC emissions from various industries within an industrial complex using a high-resolution measurement instrument. This study aimed to identify the VOC profiles and their concentrations across 12 industries. Sampling was conducted across 99 facilities in an industrial complex in South Korea, and VOC analysis was performed based on measurement data using a Proton-Transfer-Reaction Time-of-Flight Mass Spectrometry (PTR-ToF-MS). The results indicated that the emission of oxygenated VOCs (OVOCs) was dominant in most industries. Aromatic hydrocarbons were also dominant in most industries, except in screen printing (SP), lubricating oil and grease manufacturing (LOG), and industrial laundry services (ILS) industries. Chlorinated VOCs (Cl-VOCs) showed a relatively higher level in the metal plating (MP) industry than those in other industries and nitrogen-containing VOCs (N-VOCs) showed high levels in general paints and similar product manufacturing (PNT), MP, and ILS industries, respectively. The gravure printing industry was identified as the highest emitter of VOCs, with the highest daily emissions reaching 5934 mg day⁻¹, primarily consisting of ethyl acetate, toluene, butyl acetate, and propene. The findings suggest that the VOC emissions from the gravure printing and plastic synthetic leather industries should be primarily reduced, and it would be the most cost-effective approach to improving air quality. This study can provide the fundamental data for developing effective reduction technologies and policies of VOC, ultimately contributing to enhanced atmospheric models and regulatory measures. Full article

The majority of bearings in the world are lubricated by grease, and nearly 80% of premature bearing damage is attributed to lubrication issues. Accurate measurement and prediction of film thickness are crucial aspects of understanding the lubrication mechanism in grease-lubricated bearings. This work focuses on grease film thickness measurement using the capacitance method in real bearings. It comprehensively reviews the current status, identifies key challenges, and proposes solutions. Mechanisms of mainstream electronic components in capacitance measurement were reviewed for the first time. It enables more accurate capacitance measurement. A new capacitive model and electric network to measure film thickness in fully flooded, starved, and mixed regimes are developed. It is more comprehensive compared to current models. Classic dielectric models are reviewed, and suitable ones for lubricants are proposed. It facilitates a more precise film thickness measurement. Finally, a new grease film thickness model (bearing raceway) is proposed based on the 113 literature capacitive film thickness data points from five different authors. The satisfied R-squared value indicates a strong correlation. Full article

Fretting wear is a phenomenon occurring in many engineering objects, including push fit connections. In view of a large number of factors conducive to wear development, it is difficult to describe the mechanism of wear initiation and development. Therefore, various methods are sought to limit wear development. The use of a lubricant may be one of those ways. The aim of this article is to present the results of testing the influence of a lubricant medium on the development of fretting wear in interference fit connections. As a lubricant medium, MoS₂ and Whitmore greases were used. For that purpose, wear tests were first conducted on the shaft/sleeve tribological kinematic pair, and then observations and laboratory measurements were performed. The observations demonstrated the presence of fretting wear traces on all tested samples, irrespective of the tribological kinematic pair being tested. The main kind of damage consisted of material build-ups which, during operation, become oxidised and, while moving along the connection, caused local abrasion and micropits. The best results in restricting the development of fretting wear were achieved with Whitmore grease. Full article

This study examines the relationship between country-level corruption (proxied by the Corruption Perception Index, CPI) and firm performance (measured by Return on Assets, ROA) across 18,286 firms in the East Asia, South Asia, and Southeast Asia regions. Additionally, the moderating effects of audit quality (proxied by auditors’ reputation) on the relationship are examined. The findings of the study indicate a positive association between corruption and ROA in high-income nations, thus providing evidence in favor of the “greasing the wheel” theory. On the other hand, a negative association is documented in the upper middle- and low-income nations, which is consistent with the “sanding the wheel” notion. Notably, audit quality has a positive moderating influence on the relationship between corruption and ROA, especially in nations with low corruption levels, reaffirming the pivotal role of reputable auditors in enhancing firm performance within these economic contexts. The results of this study have important ramifications for forming policy suggestions and enhancing governance. The findings highlight the opportunity to improve governance practices and regulations to reduce corruption and increase transparency. Policymakers can develop ways to strengthen institutional frameworks by recognizing the complex link between corruption, corporate profitability, and the function of respected auditors. Full article

Impact-sliding experiments were performed by using four self-made lithium-based greases, namely Yangtze Grease 1, Yangtze Grease 2, Yangtze Grease 3, and Yangtze Grease 4. The influence of base oil viscosity, thickener content, and morphology of thickener fiber clusters on the lubricating state were visually explored, combined with field-emission microscopy and two-light interference technology. The grease film distribution at the middle section was measured using Dichromatic Interference Intensity Modulation (DIIM) software. All experiments were executed in a completely flooded environment. The results show that among the components of grease, the base oil’s viscosity has the greatest impact on the anti-wear performance of the grease. As the viscosity of the base oil increases, the grease exhibits better anti-wear performance. The grease film thickness under the condition of high-viscosity base oil is about 10 times higher than that under the condition of low-viscosity base oil. Secondly, the content of thickener in the grease needs to be controlled within a reasonable range. The experiments indicate that the effect of thickener content on the grease’s film-forming properties becomes more pronounced at higher speeds. From the experiment using YG 4, it can be seen that a higher thickener content under high-speed conditions increases the thickness of the lubricating grease film by about 10 times. The dimensions of the thickener fibers and the density of their entanglement structure significantly influence the rheological properties and load-bearing capacity of the grease. Larger fiber sizes and higher entanglement densities result in reduced grease fluidity and recovery but enhance its load-bearing capabilities. In order to obtain the best anti-wear performance during impact-sliding motion, the size of the thickener fiber and the density of the entanglement structure need to be controlled within an appropriate range. Full article

Bearings are one of the main components of induction motors, machines widely employed in today’s industries, making their monitoring a primordial task; however, most systems focus on measuring one physical magnitude to detect one kind of fault at a time. This research tackles the combination of two common faults, grease contamination and outer race damage, as lubricant contamination significantly impacts the life of the bearing and the emergence of other defects; as a contribution, this paper proposes a methodology for the diagnosis of this combination of faults based on a proprietary data acquisition system measuring vibration and current signals, from which time domain statistical and fractal features are computed and then fused using LDA for dimensionality reduction, ending with an SVM model for classification, achieving 97.1% accuracy, correctly diagnosing the combination of the contamination with different severities of the outer race damage, improving the classification results achieved when using vibration and current signals individually by 7.8% and 27.2%, respectively. Full article