Defective Units Research Articles

Pore engineering of MOF-808 for effective adsorption of roxarsone

The development of high-efficiency adsorbents for the removal of roxarsone from wastewater is necessary but remains difficult. Herein, a strategy of pore engineering was applied by using trifluoroacetic acid (TFA), formic acid (FA), and acetic acid (AA) as modulators to construct defective MOF-808. Physicochemical characterizations show that the type of acid modulators as well as their dosages has an impact on the material’s structure defect. Benefiting from these defective units, the diffusion and mass transfer of roxarsone in the material can be promoted. Particularly, MOF-808-AA-b with the most defects exhibits the highest adsorption capacity (860.8 mg g−1) and rapid adsorption equilibrium (360 minutes). The adsorption isotherm and adsorption kinetics conform to Langmuir isotherm model and pseudo-second-order kinetic model, respectively. Adsorption thermodynamics indicates that the adsorption process was spontaneous and endothermic. Experimental characterization and density functional theory calculation jointly demonstrate electrostatic attraction, hydrogen bonding, π-π interactions, coordination interaction and pore-filling promote the roxarsone adsorption on MOF-808-AA-b. Additionally, this adsorbent possesses excellent chemical stability, outstanding anti-interference ability and regeneration-recycling performance. Thus, our work provides a powerful guidance in the optimization of modulators for constructing a high-efficiency adsorbent.

Quality Control Analysis Using the Failure Mode and Effect Analysis Method

This study aims to identify critical factors contributing to defects in Epodion rh-Erythropoietin Alfa syringes and propose strategies to minimize production flaws. Through Failure Modes and Effect Analysis (FMEA), the research identified cracking as the predominant defect, accounting for 43 out of 62 observed syringe flaws in a production batch of 162,332 units. The Risk Priority Number (RPN) calculation yielded a score of 162, indicating material-related issues as the primary concern. Consequently, the study recommends stringent quality testing of raw materials to enhance material strength and diminish product defects, thereby bolstering overall manufacturing quality. Highlights : The study aimed to investigate factors contributing to defective Epodion® rh-Erythropoietin Alfa syringes, with a focus on reducing cracks during manufacturing. A Failure Mode and Effect Analysis (FMEA) approach was used to identify the primary causes of failure, revealing cracking as the predominant issue affecting 43% of defective units. Enhanced quality control measures for raw materials prior to their utilization within the production process were recommended to minimize product defects. Keywords: Epodion, rh-Erythropoietin Alfa, syringes, FMEA, quality control.

Analysis of Furniture Product Quality Control with Statistical Quality Control Methods and Failure Mode and Effect Analysis

PT. Tjakrindo Mas is a manufacturing company based in Indonesia that supports the government, industrial, public, and private sectors. Established in 1984, the company produces home furniture made from various types of wood. During the period from December 2023 to May 2024, the company faced production issues with its furniture products. According to production scheduling data, the furniture production intensity was high, operating 5 days a week. During this period, the highest production rate was for the 2 Door Glass Wardrobe, totaling 5,638 units. However, despite the high production volume, the defect rate for the 2 Door Glass Wardrobe was also high, with 498 defective units, representing a defect rate of 8.83%, which exceeds the company's tolerance standard. The objective of this study is to assess the quality of the Glass Wardrobe product at PT. Tjakrindo Mas and to propose improvements to enhance the product quality. Observations identified that the highest Risk Priority Number (RPN) was associated with the close side rail rupture defect, caused by the operator not being careful when installing the close side rail to the cabinet body, and the work methods used not in accordance with the Standard Operating Procedure (SOP). Recommendations for quality control proposals based on the high RPN value of FMEA Close Side Rail Rupture is to provide supervision and guidance to workers, and Provide briefing to operators about methods that are in accordance with the standard operating procedures (SOP) used by the company.

Construction of defective hydroxyl-rich metal–organic framework for effective capture of borate ion

Developing high-efficiency adsorbents for borate ion still remains up to now. Herein, a facile and green method is used to obtain serial hydroxyl functionalized UiO-66-(OH)2-AA-X (AA, acetic acid; X, AA usage) by using AA as a modulator. The addition of AA can induce the generation of defect units in the adsorbents due to its partial substitution for the organic linkers. It is found that the defect degree as well as the porosity can be neatly regulated by the AA amount. In particular, UiO-66-(OH)2-AA-20 with the most defects exhibits a high adsorption capacity (891.1 mg g−1) towards borate ion, outperforming the most previously reported adsorbents. The adsorption reaches equilibrium at 600 min. The adsorption behavior can be well described by the Langmuir isotherm model and pseudo-second-order model. Besides, UiO-66-(OH)2-AA-20 possesses a wide pH (3–10) tolerance, excellent anti-interference ability, and good reusability. A combination of experimental characterization and density functional theory calculation indicates the free hydroxyl groups serve as the main adsorption sites, and the adsorption-driven forces involve electrostatic, coordination, hydrogen bonds and π–π stacking interactions. On these basis, our work may provide a guideline for constructing high-efficiency defective adsorbents for borate ions via a modulated strategy.

Single-molecule magnet behavior in heterometallic decanuclear [Ln2Fe8] (Ln = Y, Dy, Ho, Tb, Gd) coordination clusters.

Five decanuclear lanthanide-iron clusters, formulated as [Ln2Fe8(hmp)10(μ2-OH)4(μ3-OH)2(μ4-O)4(H2O)6]·6ClO4·xH2O (x ≈ 8, Ln = Y for 1; x ≈ 6, Ln = Dy for 2; x ≈ 6, Ln = Ho for 3; x ≈ 7, Ln = Tb for 4; x ≈ 7, Ln = Gd for 5, Hhmp = 2-(hydroxymethyl)pyridine), have been synthesized and structurally characterized. Single-crystal structural analysis reveals that the cluster consists of six face-sharing defective cubane units. Dynamic magnetic investigations indicated that cluster 2 exhibits single-molecule magnet behavior under a zero dc field eliciting an effective energy barrier of Ueff = 17.76 K and a pre-exponential factor of τ0 = 7.93 × 10-8 s. Investigation of the performance of a series of FeIII-DyIII SMMs indicates that the relatively low energy barrier in 2 is associated with the weak ferromagnetic coupling between FeIII and DyIII ions, while the strength of ferromagnetic interaction in these clusters is mainly related to the bond distances between DyIII and O atoms coordinated to FeIII ions. Clusters 3 and 4 exhibit similar dual relaxation pathways under their respective optimal external applied dc field, where the direct relaxation process occurs in the low-frequency area, which impedes the extraction of the Ueff, while the secondary relaxation process appears at a higher frequency, which is probably a connection with intermolecularly driven relaxation. Our findings offer a magneto-structural correlation model for further investigating the single-molecule magnet behavior in lanthanide-iron systems.

Study on the poroelastic behaviors of the defected osteochondral unit.

Osteoarthritis has become a major disease threatening human health. The mechanism of injury under fluid involvement can be studied by finite element method. However, most models only model the articular cartilage to study the subchondral bone structure, which is too simplistic. In this study, a complete osteochondral unit was modeled and provided with a poroelastic material, and as osteoarthritis develops and the size, thickness, and shape of the osteochondral unit defect varies, the fluid flow behavior is altered, which may have functional consequences that feed back into the progression of the injury. The results of the study showed that interstitial fluid pressure and velocity decreased in defective osteochondral units. This trend was exacerbated as the size and thickness of the defect in the osteochondral unit increased. When the defect reached the trabeculae, pressure around the cartilage defect in the osteochondral unit was greatest, flow velocity in the subchondral cortical bone was greatest, and pressure and flow velocity around the trabecular defect were lowest. As osteoarthritis develops, the osteochondral unit becomes more permeable, and the pressure of the interstitial fluid decreases while the flow rate increases, resulting in severe nutrient loss. This may be the fluid flow mechanism behind osteochondral defects and osteoarthritis.

Selective oxidation of methacrolein to methacrylic acid over CsH3PMo11VO40 with structural defects

A novel synthetic strategy using microwave-assisted precipitation was proposed to prepare defective CsH3PMo11VO40 for the oxidation of methacrolein (MAL) to methacrylic acid (MAA). A systematic comparison of catalysts synthesized using different heating methods and preparation conditions was conducted. Microwave treatment was found to accelerate the crystallization rate of the catalyst and increase vanadyl species (VO2+) content on its surface, yielding the formation of defective Keggin structures. A moderate degree of defective Keggin units improves the oxidation capacity of active Mo species and facilitates the activation of oxygen into lattice oxygen, enhancing the oxidation of MAL. Therefore, the catalyst obtained through microwave heating demonstrates significantly improved catalytic performance compared to the one prepared via conventional heating. The defective Keggin structure plays a key role in catalytic enhancing. Under optimal conditions, the 70MH-40 catalyst exhibits the highest MAL conversion of 90.3% and MAA selectivity of 87.2%.

Analysis of geometric defects in square locally resonant phononic crystals: A comparative study of modeling approachesa).

Phononic crystals can develop defects during manufacturing that alter the desired dynamic response and bandgap behavior. This frequency behavior change can enable successful defect inspection if the characteristic defect response is known. In this study, the behavior of a defective square unit cell comprising a freed and shortened leg is studied using a wave finite element method and an approximate continuous-lumped model to elucidate the defect induced qualitative dynamical features. These metrics are a computationally inexpensive alternative to modeling a defective unit cell within a large pristine array entirely in finite elements. The accuracy of these models is validated by comparing the result to a full finite element model. The impact of a shortened unit cell leg on the behaviors of an infinite array of defective cells and a finite array with a single defect are successfully predicted through dispersion curves and frequency response functions, respectively. These methods reveal defect-induced modes that split the local resonance bandgap of the pristine cell, as well as new anti-resonances resulting from the shortened leg. The study uses both approaches to evaluate the effect of defects in complex phononic crystal geometries and provides a comparative evaluation of the results of each model.

Defective Potassium Poly(Heptazine Imide) Preventing Spin Delocalization and Hole Transfer Deactivation for Efficient Solar Energy Conversion and Storage.

Anti-site defective potassium poly(heptazine imide) (KPHI) with the central nitrogen atoms partially replaced by graphitic carbon atoms in the flawed heptazine rings is prepared by direct ionothermal treatment of the rationally designed supramolecular complex in KSCN salt molten. Compared to the KPHIs without the anti-site defect, the anti-site defective KPHI demonstrates significantly improved photocatalytic and dark photocatalytic performances for H2 evolution reaction (HER). In the presence of the hole scavenger, the anti-site defective KPHI exhibits superior photocatalytic stability for HER lasting 20h, whereas the deactivation is observed from the ordinary KHPIs after 3h HER. Moreover, the H2 yield in the dark by the stored photoelectrons in the anti-site defective KPHI increases by more than an order of magnitude. Density functional theory calculations reveal that the anti-site defective unit in KPHI not only prevents spin delocalization but also inhibits the deactivation of hole transfer, which are beneficial to photoelectron storage and photocatalytic activity. The findings in this study provide insight into the photophysical and catalytic properties of KPHI, which conclude a strategy to improve the performances for solar energy conversion and storage by incorporating intrinsic anti-site defects in KPHI.

Intermittent sampling for statistical process control with the number of defectives

An intermittent sampling model for statistical process control (SPC) is introduced to monitor the quality of output from a production process where the number of defective units in a sample is measured in selected time periods. A Limited Memory Influence Diagram (LIMID) model is implemented to determine the time periods in which to collect samples and the decision strategy to minimize total costs of quality control. In periods where samples are collected, the observed defectives determine whether the process is stopped to investigate and repair an assignable cause of variation. Based on sample results, the process can alternatively be allowed to run without interruption until the next predetermined sampling interval, or the results may suggest collecting a sample again in the next period. The model only requires the user to know the result of the current sample to make a decision, in contrast to Bayesian methods that require calculations based on all prior samples and a history of actions. Despite the limited and intermittent nature of the information, the model provides lower quality costs than existing methods for a wide range of production time horizons.

Flexible composition-dependent third-order optical nonlinearity of chalcogenide glasses within a Ge-Ga-S ternary system

In this work, we present a systemic study with respect to the third-order optical nonlinear (TONL) features of chalcogenide glasses (ChGs) within a germanium-gallium-sulfur (Ge-Ga-S, GGS) ternary system. The research outcomes show that the TONL attributes of GGS ChGs are highly tunable by glass composition, and the flexibility is higher than many other reported ChG systems. We have found that the TONL attributes of GGS ChGs depend remarkably on the deviation level of glass composition from chemical stoichiometry, which is associated with the presence of different types of defective units in the GGS glass network. The TONL dispersion of GGS ChGs is discovered to deviate from the classic theories based on crystalline semiconductors, as a result of the presence of multiple-steps absorption process occurred between gap states near the band gap, which renders the GGS ChGs applicable for various types of nonlinear optical functionalities.

Frequency splitting of hemispherical resonators trimmed with focused ion beams

This paper studies a high-precision etching process based on focused ion beam static trimming of the defective mass of fused silica hemispherical resonators to eliminate frequency splitting. This trimming method effectively overcomes the shortcomings of inefficiency and poor robustness, and the accuracy is seriously dependent on the stability of the trimming equipment in the traditional approach based on the harmonic form of trimming. The vibration model of an imperfect hemispherical resonator is firstly established by equating structural defects into point mass defective units, revealing that the frequency splitting is a function of the size of the equivalent defect mass and that the angular position of the stiffness axis is determined by the spatial distribution of the defect mass, which further elucidates that the frequency splitting of the resonator is the equivalent form of the defect mass on its low-frequency axis. To validate the accuracy of the present method, a simulation model of the imperfect resonator is established, and the results show that the theoretical model is in good agreement with the finite element method. Then, a high-precision nonlinear parameter identification model containing frequency splitting and low-frequency axis azimuth parameters is established based on the standing wave oscillation effect and spectral analysis, and the frequency splitting and low-frequency axis azimuth are identified by analyzing the vibration function of the hemispherical resonator. Finally, based on the parameter identification results and the ion beam removal function analysis, an ion beam trimming process is designed to eliminate frequency splitting by trimming the defective mass on the low-frequency axis. The results show that the frequency splitting after mass trimming is better than 0.001 Hz, significantly improving the hemispherical resonator's performance.

A sustainable two-echelon green supply chain coordination model under fuzziness incorporating carbon pricing policies.

Noxious effect on environmental due to carbon emissions is being addressed worldwide by governments through carbon pricing instruments. Two of prevalent instruments adopted by governments are simple carbon tax and cap-and-trade policy. Effectiveness of carbon pricing instruments towards achieving reduction in carbon emissions is a matter of study on one hand. Whereas, the planning of supply chain operations under imposition of such financial instruments is a challenge for small and medium scale business enterprises. Addressing this situation, the present study develops a supply chain model for coordinated planning of production and inventory replenishment schedules along with decision on economic amounts of expenditure for green resources. This decision model is formulated separately under the enforcement of each of two carbon pricing policies. The study focuses a manufacturer-retailer duo which works by adopting certain sustainability and conservation practices. Manufacturer reworks on rectifiable proportion of defective units, while retailer launches discounts-based sales of partially damaged units. The decision-making model developed in this study incorporates such activities. Furthermore, practical aspects like a slowdown in production due to unforeseeable disruptions and the effect of the quality of product and advertisement campaigns on demand rates are included in the proposed model. Under the purview of each carbon pricing policy, decision-making model is formulated as a nonlinear constrained optimization problem with objective towards profit maximization. A novel conception of fuzziness has been suggested for tackling imprecision in the assessment of certain parameters involved in the model. A numerical study on an appropriate case of a manufacturer-retailer duo system is presented. Empirical results of numerical study evince that a substantial reduction in carbon emission is achieved, even with an escalation in the profit through appropriate green expenditure. This trend is observed under the imposition of each of the carbon pricing policies, thereby substantiating an encouragement to supply chain partners for making expenditures on green resources. Thereby, the hypothesis of getting desired response on curbing emissions by incentivization through carbon pricing is satisfied in the studied case. Furthermore, a sensitivity analysis concludes the stability of formulated model against most of the parameters involved.

Comparative study of pre- and postauricular flaps for external auditory canal defect reconstruction

BackgroundMalignancies involving the external auditory canal deserve critical evaluation due to this area's aesthetic and functional importance. Flaps can be very useful for the restoration of the external auditory canal. A variety of flaps available for the surgical treatment of external acoustic meatus defects exist, depending on the precise location and size. ObjectivesOur study aimed to compare aesthetic and functional results in the postoncological reconstruction of external auditory canal defects using a preauricular flap and postauricular revolving door flap. MethodsSixteen patients treated at our plastic surgery unit for defects involving the external auditory canal between January 2014 and December 2020 were included in the study. All defects were the result of a primary or secondary skin cancer excision. Patients were divided into two groups, one receiving the preauricular flap technique and the other the postauricular revolving door flap technique. ResultsThree separate visual analog scales reported excellent scores for the two procedures, though the postauricular revolving door flap had slightly better results. Both preauricular flap and postauricular revolving door flap reconstructive techniques showed good options for external auditory canal reconstruction in postexcision skin cancer patients. From an aesthetic point of view, the revolving door flap appeared to be a more elegant surgical approach in this type of reconstruction because the scar was hidden in the postauricular sulcus. ConclusionsReconstruction with a postauricular revolving door flap allowed for a more natural movement with no external pedicle. Evidence-Based Medicine (EBM) LevelIV

Editorial: Toyota Production System practices asFast‐and‐Frugalheuristics

Editorial: Toyota Production System practices as<scp>Fast‐and‐Frugal</scp>heuristics

Construction of defective zirconium-based metal–organic frameworks for enhanced removal of toxic selenite: performance and mechanism studies

The development of effective adsorbents for the adsorption and removal of toxic selenite (SeO32−) from wastewater is urgently required but challenging. Herein, formic acid (FA), a monocarboxylic acid, was used as a template to construct serial defective Zr-Fumarate (Fum) -FA based on a green and facile preparation method. Physicochemical characterization shows that the defect degree of Zr-Fum-FA can be flexibly controlled by regulating the amount of FA to be added. Owing to rich defect units, the diffusion and mass transfer of guest SeO32− into the channel can be boosted. Particularly, Zr-Fum-FA-6 with the most defects exhibits superior adsorption capacity (519.6 mg g−1) and rapid adsorption equilibrium (∼200 min). The adsorption isotherms and kinetics can be well described by the Langmuir and pseudo-second-order kinetic models. Moreover, this adsorbent possesses excellent resistance towards co-existing ions, high chemical stability and good applicability in a broad pH range of 3–10. Thus, our study provides a promising adsorbent for SeO32−, and more importantly, it proposes a strategy for rationally tailoring the adsorption behavior of adsorbents via defect construction.

Efficient and Trusted Data Sharing in a Sharding-Enabled Vehicular Blockchain

Data sharing is essential for future autonomous vehicles in vehicular networks. Building trust in the shared data can be challenging among mutually unknown vehicles in an open and distributed environment. Blockchain is the key to establish trusted data sharing in a decentralized vehicular environment. However, the low efficiency (e.g., transaction per second, TPS) of blockchain is the bottleneck for the efficient data sharing. Moreover, the highly dynamic topology, the imperfect wireless links, and the limited radio coverage may further slow down the blockchain consensus process. To improve the efficiency and trustworthiness of data sharing in a vehicular network, we propose a sharding-enabled vehicular blockchain system. Specifically, the blockchain-enabled vehicles are dynamically allocated to different shards based on their geographical locations so that transactions are processed in parallel. We design an efficient and trusted sharding-enabled blockchain consensus mechanism by integrating a reputation-assisted intrashard consensus and a vehicle-assisted inter-shard consensus. The reputation assistance in intra-shard consensus is designed to defend against the collusive false-block attack that may happen in a small-scale shard environment. The vehicle-assisted intershard consensus is designed to tackle the issues caused by defective roadside units (RSUs). Simulation results demonstrate the improved performance on efficiency and trustworthiness of the proposed system. In addition, trusted data sharing can be established even under the conditions of malicious vehicles or attacked RSUs.

An overview of light-curing within orthodontics

The use of light to initiate bonding reactions has become an integral part of orthodontic practice. Different technologies are available to cure dental composite, each with advantages and drawbacks. The efficacy of light-curing is affected by a range of factors and it is important for orthodontists to understand these concepts, alongside common problems with light-cure units, to aid in troubleshooting. Periodic testing of light-curing equipment can help to identify defective units that can potentially contribute to bond failure. CPD/Clinical Relevance: An understanding basic materials science in relation to dental light-curing technology is important in allowing orthodontists to maintain safe and effective equipment. The choice of light-curing equipment and method of use can influence bond strength and, therefore, treatment success.

ML in the Electronics Manufacturing Industry

The manufacturing of electronics is renowned for emphasizing efficiency and precision. A single error can result in a defective unit, and a defective unit is a loss. The electronic marketplace is arguably the business that has risen to the top the quickest. Particularly in the electronics manufacturing industry, AI and ML have a wide range of uses, from waste reduction to improved forecasts and quality control. Manufacturers may lower expenses, cut down on mistakes, streamline supply chains, and boost productivity across the board with machine learning. At its core, ML uses statistical and probabilistic methods to draw insights from data and make predictions. Manufacturers face some difficulties as a result of the widespread use of electronic devices and systems and the complexity of their production. AI and ML have swiftly established themselves as indispensable instruments for streamlining the production process. It can be helpful to observe how AI and ML are being used in an actual manufacturing setting to fully grasp their potential. The application of Machine Learning in the electronics industry is a revolutionary development that has opened up a world of possibilities. It has enabled manufacturers to improve productivity, reduce costs, and create products that are more tailored to consumer needs. With its ability to provide a more efficient way of analyzing data and making decisions, Machine Learning can help electronics companies to better understand consumer behaviour and develop products that are better suited to customer preferences.

Controllable synthesis of mesoporous KL zeolites via a simple one-step strategy

A simple strategy with additional KF in the synthesis gel was developed to fabricate mesoporous KL zeolites with tunable morphology, hierarchical structure and catalytic selectivity. By modulating the molar ratio of KF/Al2O3 from 0 to 10, the morphology of resultant KL zeolites changed from cylinder, to gyro shape, and to loosen stacking nanocrystal aggregates. The value of BET surface and pore volume for synthesized KL zeolites increased with increasing the KF, indicating the hierarchical structure of mesoporous KL zeolites can be systematically tailored by tuning the concentrations of KF. The effect of KF on the crystallization process of KL zeolites was also investigated, it revealed that the K+ played a crucial role to produce a large number of nucleation centers as the structure directing agent, which not only significantly shortened the crystallization time but also generated the defective growth units by influencing the electric balance between K+ with negative aluminosilicate species, leading to the formation of mesopores. Besides, the introduction of mesopores in KL zeolites can greatly improve the selectivity of bulk products in the alkylation between phenol with tert-butyl alcohol owing to the opened mesoporosity.