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The removal of CH4 is critical to address environmental concerns for developing natural gas vehicles (NGVs), because CH4 has a 20-fold-greater contribution to the greenhouse effect than CO2. Alumina supported Pd catalysts are widely used for CH4 oxidation due to their superior catalytic activity and durability compared to other CH4 oxidation catalysts. However, the continuous deactivation of Pd-based catalysts during vehicle applications needs further development of active and durable catalysts. Here, we report that Pd/SiO2 can be active and durable catalysts for CH4 oxidation in practically relevant condition via a simple reductive regeneration. CH4 oxidation light-off curves of freshly prepared Pd/SiO2 (air, 550 °C) present higher activity than those of Pd/Al2O3, but severe deactivation was observed after hydrothermal aging (HTA, air with 10% H2O) at 850 °C. However, X-ray diffraction (XRD), scanning transmission electron microscopy (STEM) and volumetric CO adsorption suggest that Pd/SiO2 has similar particle sizes as Pd/Al2O3 even after HTA, indicating that Pd/PdO particle sintering is not the origin of the deactivation of Pd/SiO2. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) shows that the CO was not adsorbed on Pd/SiO2 after HTA, whereas it was adsorbed on Pd/Al2O3 after HTA. These results demonstrate that the deactivation of Pd/SiO2 originates mainly from the blockage of the Pd/PdO surface by the SiO2 overlayer formed during HTA. The Pd/PdO surfaces are re-exposed by a simple H2 treatment at 500 °C, resulting in CO adsorption on the Pd/PdO surface and regeneration for CH4 oxidation activity, which suggests that the Pd/PdO surface was re-exposed by a reduction treatment. This work also demonstrates that SiO2-supported Pd catalysts can be a good candidate for active and durable CH4 oxidation catalysts by using the proper regeneration protocols.

Plateau honing is used as a surface finishing and texturing process to reduce the friction between the piston and the cylinder bore in internal combustion engines. However, according to some studies, honing has detrimental side effects such as friction increase and the unintentional production of defects in the cylinder liner surface. This paper investigates the performance and side effects of the uneven plateau-honed surfaces. Friction, wear, and failure tests were conducted to compare the performance of the plateau-honed surfaces with different levels of roughness and different profiles. In this work, the ground surfaces without honing marks outperformed the honed surfaces under boundary and mixed lubricant conditions. The effects of surface roughness on friction and wear were more significant than differences in the surface profile. In addition, larger and sharper wear particles detached from the edges of the honing grooves because of local stress concentration and left deep wear tracks in the cylinder bores.

Job processing times change over time in real-life production and manufacturing systems due to various factors including machine or worker learning, machine deterioration, production system upgrade...

Purpose Successful implementation of construction projects is one of the crucial factors for the economic development of every country. The main part of the countries’ capital is allocated to civil and infrastructure projects annually, most of which are accomplished with delay. Construction projects are often criticized for overrunning time and budgets. Analyzing the factors causing delay is essential for omitting them and timely implementation of these projects. Due to the importance of oil projects, this study aims to investigate and analyze the factors causing a delay in Iran’s oil construction projects. Design/methodology/approach In this research, after a broad literature review, using the fuzzy Delphi method, a total of 75 delay factors were identified under 11 major categories of owner, contractor, consultant, equipment, labor, materials, design, contract and contractual relations, laws and regulations, environmental factors, and managerial factors. Then, by using the best-worst method, the factors were prioritized. Findings The results showed that sanction, governmental management systems, weak project management by the contractor, technical and managerial weaknesses of the consultant, financial problems and delay in payment by the owner, low efficiency of the equipment, low productivity of the workforce, changes in laws and regulations, inappropriate organizational structure linking to the project, changes in the design, and changes in the price of materials are the most crucial factors causing a delay in Iran’s oil construction projects. Research limitations/implications These findings are expected to have significant contributions to Iran’s oil construction industry in controlling the time overruns in construction contracts. Originality/value The main contribution of this study is to develop a comprehensive framework in which, causes of delay in Iran’s oil construction projects are addressed and prioritized.

The properties and H2O adsorption characteristics of two types of zeolites (3A and 13X) with the same shape but different element composition were identified. These zeolites are used in gas purification processes to manufacture 9N ultra-pure inert gases for semiconductor process applications. To analyze the shape and microstructure of the zeolites, an optical microscope and FE-SEM were used. EDS, micro-Raman, and XRD analysis were conducted to analyze their compositions and properties. BET analysis was performed to identify their specific surface areas. Finally, a breakthrough analysis was conducted at room temperature. Based on the results of the optical and microstructure analyses, the cylindrical shaped 3A and 13X were determined to be composed of 2.5-um polyhedrons and 1.4-um massive shapes, respectively. The results of the compositional analysis showed that the main components of both zeolites were Si and Al, whereas K and Na existed in 3A and 13X, respectively. The results of the specific surface area analysis demonstrated that the surface area of 13X was 32 times larger than that of 3A. Specifically, the total specific surface areas were 22.42 and 720.33 m2/g for 3A and 13X, respectively. The results of the H2O adsorption characteristic analysis showed that the H2O concentration of 13X was 1.33 times higher than that of 3A. Therefore, with respect to using zeolite for gas purification process applications, 13X might be more suitable to achieve excellent specific surface area and remarkable H2O adsorption.

Changes in the pore size, porosity, compressive strength, and thermal conductivity of closed-pore foam glass with a pore size of 450 µm upon the addition of 0–24 wt% of polysiloxane at a low sintering temperature of 750 °C were investigated. Micro-Raman analysis demonstrated the uniform dispersion of polysiloxane after sintering, and it was confirmed that the entire foam glass processed to have closed pores. With increasing polysiloxane, the pore size decreased from 452 μm to 131 μm, and the porosity decreased from 62% to 41%. The compressive strength increased from 2.0 to 5.7 MPa, and the thermal conductivity also increased from 0.146 to 0.233 W/m·K. However, when more than 15 wt% of polysiloxane was added, the thermal conductivity exceeded 0.160 W/m·K, rendering unsuitable as an insulating material. Therefore, we fabricated closed-pore foam glass with proper pore size and porosity, a strength of 4.1 MPa, and a low thermal conductivity below 0.160 W/m·K by adding 15 wt% of polysiloxane at a low sintering temperature.

Electric Power Steering (EPS) is rapidly evolving in terms of performance. However, the abnormal noise from steering, which is experienced by the drivers, reduces the perfection of performance. In this study, the deterioration of Rack-based Electric Power Steering (R-EPS) samples by mileage was analyzed to investigate the cause of steering abnormal noise in the R-EPS applied to a large-sized luxury vehicle that is more sensitive to noise. The results from our analysis showed that the ball nut and screw in the ball nut assembly of R-EPS were in the mode of normal wear. However, the steel ball between the ball nut and screw showed irregular wear mode. It was found that the ball Φ5 has a larger contact area than the ball Φ4, which is advantageous for abrasion and irregular wear because stress is dispersed in the load. Moreover, the ball with Φ5 was superior to the ball with Φ4 in the results of abrasive and adhesive wear tests verified by the ball-on-disk test. Therefore, in the future R-EPS development, the ball with Φ5 compare to the ball with Φ4 should be proposed for the ball nut assembly. This is in order to eliminate the potential cause of steering abnormal noise.

As a blowing agent, 2–10 wt% of nanocarbon (NC) was added 10 µm glass powder (CaO, MgO, Al2O3, SO3, 83 wt%-SiO2) and sintered at 700–900°C to fabricate foamed glasses with closed pores that were 62–2200 µm. Optical microscopy was used to examine the microstructure and pore size. Compressive strength tester and a heat flow meter were used to examine the changes in mechanical strength and thermal conductivity. The microstructure examination results showed that was performed at 700°C, 297.9–351.3 µm pores were fabricated, and the porosity was 57–63 % in the sample that contained 6–10 wt% NC. At sintering temperatures above 750°C, the pore size increased as the NC content and the sintering temperature increased. The thermal conductivity was maintained at less than 0.28 W/m‧K. Therefore, it is possible to use 6–8 wt% NC as a blowing agent in glass material to produce foamed glass that has closed pores of approximately 500 µm with better or equivalent compressive strength and thermal conductivity properties than existing 1000 µm grade foamed glass, despite being sintered at a temperature of approximately 100°C lower.

The changes in mechanical properties and thermal conductivities of fiber reinforced foam glass produced by adding 0 ~ 50 wt% basalt-fibers to 10 µm glass powder containing 6 wt% nano-carbon via low-temperature sintering at 750 °C were examined. The prepared basalt-fibers had an aspect ratio of 70.88. To study the microstructure of the foam glass, optical microscopy and scanning electron microscopy were conducted. To assess the mechanical properties and thermal conductivity of the sample, a compressive strength tester and a heat flowmeter were used, respectively. The sample was confirmed to have closed pores up to the addition of 15 wt% basalt-fiber, with open pores being observed from 20 wt% or more. Microstructure analysis showed that the sample was shown to have dense basalt-fiber clusters with an even distribution of pores at 13 wt% basalt-fibers, whereas irregular pores formed with more basalt-fiber addition. Compressive strength was increased by approximately 48 % compared to the sample without basalt-fiber addition while the sample with 13 wt% basalt-fibers showed gradual improvement up to a total of 2.96 MPa and then a gradual decrease with more addition. The thermal conductivity was seen to increase from 0.16 to 0.28 W/m·K with increasing basalt-fiber addition; nevertheless, the properties were suitable for using the samples as a thermal insulator.

Backgroud: Accurate detection and grading of cataract is pivotal in providing personalized precision treatment strategies for preventing visual loss. We develop and validate an automated deep learning (DL)-based artificial intelligence (AI) platform for diagnosing and grading cataracts, using slit-lamp and retro-illumination lens photographs based on the Lens Opacities Classification System-Ⅲ (LOCS-Ⅲ). Methods: Slit-lamp and retro-illumination lens photographs were graded by two trained graders using LOCS-III. Image datasets were labeled and divided into training, validation, and test datasets. We trained and validated AI platforms with four key strategies in the AI domain: (1) region detection network for redundant information inside data, (2) data augmentation and transfer learning for the small dataset size problem, (3) generalized cross entropy loss for dataset bias, and (4) class balanced loss for class imbalance problems. The performance of the AI platform was reinforced with an ensemble of three AI algorithms (ResNet18, WideResNet50-2, and ResNext50). Finding: The AI platform showed robust diagnostic performance (AUC of 0.9992 [0.9986-0.9998], 0.9994 [0.9989-0.9998]; accuracy of 98.82% [97.7-99.9], 98.51% [97.4-99.6]) and grading prediction performance (AUC of 0.9567 [0.9501-0.9633], 0.9650 [0.9509-0.9792]; accuracy of 91.22% [89.4-93.0], 90.26% [88.6-91.9]) for nuclear opalescence (NO) and nuclear color (NC) using slit-lamp photographs. For cortical opacity (CO) and posterior subcapsular opacity (PSC), the system achieved high diagnostic performance (AUC of 0.9680 [0.9579-0.9781], 0.9465 [0.9348-0.9582]; accuracy of 96.21% [94.4-98.0], 92.17% [88.6-95.8]) and good grading prediction performance (AUC of 0.9044 [0.8958-0.9129], 0.9174 [0.9055-0.9295]; accuracy of 91.33% [89.7-93.0], 87.89% [85.6-90.2]) using retro-illumination images. Interpretation: Our DL-based AI platform successfully yielded accurate and precise detection and grading of NO and NC in seven-level classification and CO and PSC in six-level classification, overcoming the limitations of medical databases such as small training data or biased label distribution. Funding: This work was supported by the National Research Foundation of Korea grant funded by the Korean government's Ministry of Education (NRF-2021R1C1C1007795; Seoul, Korea), which was received by D.H.L. Declaration of Interest: The authors declare no conflict of interest Ethical Approval: The study was approved by the Samsung Medical Center Institutional Review Board (IRB file number 2020-08-035)

This paper considers a single-machine scheduling problem with sequence-dependent setup times and energy-generation and storage systems. Each job requires a sequence-dependent setup to be processed on the machine, and both setup and processing of the job require job-dependent amounts of energy. The energy consumed by the machine can be bought from an Electric Power Company (EPC) or generated by own Distributed Energy Resource (DER), such as solar photovoltaic or wind, and the energy can be stored in an Energy Storage System (ESS). The objective is to minimise the total cost, the sum of production cost depending on makespan and energy cost by considering energy usage from the EPC, DER and ESS. For the problem, a mathematical programming model is first derived by using period-based indexes. Then, a hybrid genetic algorithm, which adds appropriate idle times between jobs and determines an efficient energy schedule by storing some energy during less expensive periods into the ESS for later use in high-price periods, is developed. Finally, computational experiments show that the proposed algorithm provides effective solutions, and which component of the total cost affects the performance the most, how effective adding idle times between jobs is, and how much cost can be saved by having a DER and ESS.

Depression causes mental and physical changes which affect quality of life. It is estimated to become the second most prevalent disease, but despite its commonness, the pathophysiology of depression remains unclear and medicine is not sufficiently protective. p-Coumaric acid (p-CA) is a dietary phenolic acid which has been proven to have antifungal, anti-HIV, anti-melanogenic, antioxidant and anti-inflammatory effects. Considering these effects, we investigated whether p-CA can prevent depressive symptoms by reducing inflammatory cytokines in animals injected with lipopolysaccharide (LPS). Changes in despair-related behaviors, inflammatory cytokines, neurotrophic factors and synaptic activity were measured. In these animals, p-CA improved despair-related behavioral symptoms induced by LPS in the forced swim test (FST), tail suspension test (TST) and sucrose splash test (SST). p-CA also prevented the increase of inflammatory cytokines in the hippocampus such as cycloxigenase-2 and tumor necrosis factor-α due to LPS. Similarly, it prevented the reduction of brain-derived neurotrophic factor (BDNF) by LPS. Electrophysiologically, p-CA blocked the reduction of long-term depression in LPS-treated organotypic tissue slices. In conclusion, p-CA prevented LPS-induced depressive symptoms in animals, as determined by behavioral, biochemical and electrophysiological measures. These findings suggest the potential use of p-CA as a preventive and therapeutic medicine for depression., Graphical Abstract

In case of the diesel engine, the optimal control of interacting surfaces for improving the performance of engine becomes important more than before, especially in designing the surfaces of cylinder liners. The plateau honing technology has been developed on the cylinder liners of the large ship engines and the automotive engines. A plateau honing is a kind of metal removal process, which leaves a substantially flat or plateau finish with much greater bearing area, while maintaining a cross hatch pattern of valleys for oil retention. However, the valley produced by honing functions as an oil repository has a fatal role in the formation of fluid dynamic pressure on interacting surfaces. The friction and wear tests with reciprocating motion were performed to compare the lubricity of sliding cylinder liner surfaces with each different mark of plateau honing. The friction and wear of surfaces with each different depth of profiles, which were used as the honing mark of the marine diesel engine, were compared with those of randomly ground surfaces. From the tests with the deep-grooved honing marks, it was found that the severe interactions due to asperity contacts and the formation of relatively thin films produced larger amounts of wear volumes than the test with the shallow-grooved ones.