Mode Analysis Research Articles

Intermediate scattering function for polymer molecules: An approach based on relaxation mode analysis.

The theory of polymer dynamics describes the intermediate scattering function for a polymer molecule in terms of relaxation modes defined by normal coordinates for the corresponding coarse-grained model. However, due to the difficulty of defining the normal coordinates for arbitrary polymer molecules, it is generally challenging to express the intermediate scattering function for a polymer molecule in terms of relaxation modes. To overcome this challenge, we propose a general method to calculate the intermediate scattering function for a polymer molecule on the basis of a relaxation mode analysis approach [Takano and Miyashita, J. Phys. Soc. Jpn. 64, 3688 (1995)]. In the proposed method, relaxation modes defined by eigenfunctions in a Markov process are evaluated on the basis of the simulation results for a polymer molecule and used to calculate the intermediate scattering function for that molecule. To demonstrate the effectiveness of the present method, we simulate the dynamics of a linear polymer molecule in a dilute solution and apply it to the calculation of the intermediate scattering function for the polymer molecule. The evaluation results regarding the relaxation modes reasonably describe the intermediate scattering function on the length scale of the radius of gyration of the polymer molecule. Accordingly, we examine the contributions of the pure relaxation and oscillatory relaxation processes to the entire intermediate scattering function.

Dynamics and spectral character of unsteady pressure field on afterbody of generic space launcher: Transonic flows

The unsteady pressure field over an axisymmetric backward-facing step was investigated experimentally at transonic freestream Mach numbers of 1.05, 1.2, and 1.4. The study was aimed at examining the influence of transonic freestream Mach numbers on the spatio-temporal character of the unsteady pressure field and on the dominant modes/mechanisms driving it. Surface flow visualization, schlieren, and unsteady pressure measurements were carried out as part of the experimental investigation. From oil flow visualization and schlieren, the reattachment region was identified, and consequently, the mean reattachment length was estimated. The mean reattachment length shows an increase with the increase in freestream Mach number. The coefficient of mean pressure along the rearbody imitates a classical backward-facing step flow profile and can be divided into three distinct regions. The peak values of the coefficient of mean pressure and the coefficient of root mean square of the fluctuation are seen to decrease with an increase in the freestream Mach number. Conventional spectral analysis reveals that as the freestream Mach number increases, the dominant peak in the spectra shifts to lower frequencies. From the spectra, three dominant fluid dynamic mechanisms depending on the freestream Mach number have been identified. Proper Orthogonal Decomposition (POD) analysis shows that 79–84 % of the total energy contribution comes from the first six modes. The temporal dynamics of the POD modes indicate three prominent mechanisms are responsible for the unsteady pressure field. Spectral analysis of POD modes indicates that the spectra are primarily driven by the first three POD modes for freestream Mach number of 1.05 and the first two modes for freestream Mach numbers of 1.2 and 1.4. Moreover, it reveals the presence of three dominant modes, and the freestream Mach number strongly dictates the dominant mode that is driving the pressure field.

Study on the shear mechanism of horizontal joints within UVDR precast shear wall by quasi-static test and finite element analysis

This research introduced a novel precast shear wall designed to address prevalent challenges encountered in precast shear wall structures, such as issues with difficult installation, high expenses, and the uncertain quality of grouting by eliminating the connection of the vertical distributing bars. Early experimental verification of this novel structural system showcased favourable results concerning its seismic performance. Building upon this groundwork, the paper presented an elaborate horizontal joint deformation model, demonstrating its precise analysis of damage modes and interface slip in the novel structural system with high reliability. Furthermore, in an effort to enhance the damage mode of this novel precast shear wall under conditions of low axial compression ratio, the study introduced and evaluated two improvement measures through finite element parametric analysis. The findings indicated a noticeable enhancement in capacity and a simultaneous reduction in interface slip with the proposed improvement measures. Additionally, the section steel measures were more effective than the additional bars measures.

Optimization research on energy consumption and carbon emissions in hydrogen-blended natural gas pipeline networks considering compressor performance - A case study of the west-east gas pipeline (line 1)

The blending of hydrogen into natural gas can utilize existing natural gas pipeline infrastructure to achieve long-distance, large-scale, and cost-effective hydrogen transportation. However, the introduction of hydrogen poses a series of new technical and safety challenges to the operation of natural gas pipelines. Addressing these issues, this paper focuses on minimizing compressor station energy consumption and carbon emissions as objective functions, conducting a comprehensive analysis of station operation modes. Incorporating the characteristics of the model, the soft frost search strategy, the hard frost penetration mechanism, and the positive greedy selection mechanism are introduced to propose the IRIME algorithm. Comparisons are made with well-performing optimization algorithms using classical test functions to evaluate algorithm performance. To further validate the algorithm's accuracy, the West-East Gas Pipeline (Line 1) is considered, comparing the convergence speed and precision of the IRIME algorithm, leading to its selection for solving the model. Furthermore, consider analyzing the impact of different hydrogen blending ratios on the performance curves and operating points of compressors. Results indicate that compared to conditions without hydrogen blending, the compressor outlet temperature and pressure drop increase for hydrogen blending ratios of 5%, 10%, 15%, and 20%; as the hydrogen blending ratio increases, the efficiency of fuel-driven compressors, efficiency of electrically driven compressors, and average efficiency of compressor units decrease; with an increase in hydrogen blending ratio, carbon emissions from fuel-driven compressors and electric-driven compressors both decrease. In conclusion, with an increasing hydrogen blending ratio, total energy consumption increases by 3.14%, 5.69%, 8.68%, and 10.90%, while total carbon emissions decrease by 2.99%, 5.36%, 8.32%, and 10.68%. These findings provide valuable insights for operational guidance in the field.

Design of dual mode antenna using CMA and broadband dual-polarized antenna for 5G networks

This article proposes a dual mode dual-polarized antenna configuration for IRNSS and fifth generation (5G) applications, operating at a frequency of 3.5 GHz based on characteristic mode analysis (CMA), and aims to provide broadband dual-polarized functionality. The original design of the antenna is a traditional patch antenna, and its dual-polarized features are determined using characteristic mode analysis. The full-wave method is used to stimulate both orthogonal modes using a 50 Ω coaxial input line at 3.5 GHz. In this design, the circular patch has been extended into an elliptical patch through a process of mode separation. The circular patch exhibits resonance at a frequency of 2.5 GHz, whereas the extended elliptical radiator demonstrates two resonance modes at 2.5 GHz and 3.5 GHz. The operational mechanism is elucidated by modal analysis and characteristic angle. This antenna operates on two different frequencies at the 2.5 GHz IRNSS band with horizontal polarization and the 3.5 GHz 5G service with vertical polarization. The maximum gain achieved with these frequency ranges is 5.31 dBi and 4.72 dBi, respectively. A ring resonator is chosen to improve the axial ratio and impedance bandwidth of the suggested prototype. The antenna's ground plane is shaped like a rectangle and features a V-shaped slot in the radiating patch. The antenna's physical footprint is 50 mm × 50 mm × 1.6 mm and an FR4 dielectric substrate serves as its foundation. Through its interaction with a PIN diode, the diode modifies the polarization of the antenna. The antenna functions as a right-handed circular polarization (RHCP), when the diode is operational. The bandwidth from 4.3 to 7.5 GHz is covered. On the other hand, it generates linear polarization (LP) between 4.2 and 5.3 GHz. The experimental antenna is evaluated and examined for its performance characteristics. The simulations are carried out utilizing the CST simulator. A prototype antenna has been manufactured and its performance has been validated against simulated findings.

A novel failure mode and effect analysis model based on extended interval-valued q-rung orthopair fuzzy approach for risk analysis

The failure mode and effect analysis (FMEA) is an essential technique for risk assessment that can not only determine the potential failure modes, causes of failure and effects, but also expunge the potential failure modes in a system. Imprecise evaluation outcomes may be achieved due to the inherent imperfections caused by the traditional FMEA approach. Accordingly, a hybrid FMEA model based upon the interval-valued q-rung orthopair fuzzy (IVq-ROF) set and extended weighted aggregated sum product assessment (WASPAS) method is propounded to provide decision support for risk assessment. The main dedications of this investigation are as below. First, an innovative IVq-ROF score function is presented to compare the IVq-ROF numbers and the related properties of the proposed function are also discussed. Second, the IVq-ROF Aczel–Alsina operation laws are investigated and then some novel IVq-ROF Hamy mean operators are propounded on based on the advanced operations. Third, the IVq-ROF logarithmic percentage change-driven objective weighting (LOPCOW) method is advanced based on the presented score function to determine the objective importance of the risk criteria and the fuzzy full consistency method (FUCOM) is utilized to ascertain the subjective importance of the risk criteria. Fourth, a novel FMEA model based on extended WASPAS method is presented to ascertain the prioritization of failure modes. Lastly, an empirical about risk assessment in the shipbuilding process is implemented to verify the applicability and feasibility of the designed FMEA model. The comparison analysis and sensibility study are executed to demonstrate the significant merits and stability of the developed model. The best advantage of the presented model is that it not only obtains a consistent outcome and takes into account the interrelations among the risk criteria, but also addresses more problems where the weights of the criteria and experts are not determined in advance.

Rest length controlled tunable band structure in periodic tensegrity metastructure – a numerical study using a novel consistent stiffness and mass formulation

Elastic wave propagation in various periodic metastructures and its application to wave filtering, vibration isolation, acoustic cloaking, etc., have gained significant attention among researchers in recent years. Despite the presence of band gaps, traditional lattice structures lack dynamic tunability. The solution lies in using tensegrity as unit cells. This article presents analysis of tunable wave propagation through a metastructure formed by tessellation of a 2D tensegrity unit cell in one dimension. Equations of motion of the unit cell are derived with consideration of flexibility and distributed mass of the bars, which is often neglected in the literature. The formulation is extended for wave dispersion analysis using the Floquet–Bloch theory. Next, the order of the formulation is reduced for decoupled analysis of symmetric and antisymmetric modes. The dispersion relations for different modes have been validated with nonlinear as well as linearized frequency response analysis under impulse load. Next, the effect of rest length of strings and alternating arrangement of bars on band gaps is studied in detail.

Cost of Quality Management: Encouraging Business Leaders to Manage and Invest in Quality Enhancement

The quality management is a complex set of constant activities aimed at improving the quality of products and services, regularly evaluating and monitoring it, preventing defects, limiting and reducing malfunctions, and correcting production defects before and after the sale of goods. Ineffective quality management leads to such problems as product returns, claims, replacement or repair, loss of customer base, damage to brand reputation, etc. This paper aims to analyze advanced strategies, methodologies, methods and tools for effective control of quality management costs, ways and means of their strategic integration into the practice of business quality management, emphasize the importance of optimizing the cost of quality management in enterprises. The proposals developed in this article are demonstrated on the example of the woodwork division of MEKKERA (MDM), a subsidiary of the HASNAOUI Group in Algeria. An approach represented in the article combines qualitative and quantitative methods. Qualitative data collection involved semi-structured interviews with four company managers, processed using NVIVO software. The purpose of these interviews was to understand the reasons that led the company to include the evaluation of the Cost of Quality in its quality objectives for 2023, as well as the perspectives and goals aimed for by the company in this initiative. A Quantitative analysis relied on secondary data from the company’s database: direct quality costs were calculated using the P-A-F and Ferrebœuf models, prevention and detection measures’ effectiveness and production process performance were evaluated; key performance indicators for indirect quality acquisition costs were defined. Findings revealed the company exceeded set thresholds for internal and external failure costs, necessitating improvements. Ishikawa method identified causes, and corrective actions were proposed using Failure Mode and Effects Analysis (FMEA).

Analysis of the Application of Green Manufacturing with the Concept of Water Recycle System to Reduce the Use of Clean Water at Pt. Karton Cikarang

The carton packaging industry has potential and advantages that can be used to maintain and develop business operational activities, one of the potentials is liquid waste left over from the production process, as an efficiency measure and a long-term business, sustainable energy is needed as an effort to apply efficiency and effort for the survival of mankind. The purpose of this research is to find the root cause of the high use of clean water in the production process and design the reuse of recycled water in the production department so that it can reduce the use of clean water, and can implement the concept of green manufacturing at PT. Karton Cikarang. This research is quantitative using the Failure Mode and Effect Analysis (FMEA) method which allows to identify and prevent the occurrence of problems in products and processes. Based on the research conducted, it is known that the percentage of clean water use in the production department is divided into 3 parts, namely converting machines (57%), corrugator machines (27%) and finishing machines (16%) which means that the use of clean water is mostly used by converting machines and the least water use is used by finishing machines. PT. Karton Cikarang has complied with wastewater quality standards set by the government, management and monitoring efforts are also carried out to create environmental protection for humans and life in the future.

Chiral multiferroicity in two-dimensional hybrid organic-inorganic perovskites.

Chiral multiferroics offer remarkable capabilities for controlling quantum devices at multiple levels. However, these materials are rare due to the competing requirements of long-range orders and strict symmetry constraints. In this study, we present experimental evidence that the coexistence of ferroelectric, magnetic orders, and crystallographic chirality is achievable in hybrid organic-inorganic perovskites [(R/S)-β-methylphenethylamine]2CuCl4. By employing Landau symmetry mode analysis, we investigate the interplay between chirality and ferroic orders and propose a novel mechanism for chirality transfer in hybrid systems. This mechanism involves the coupling of non-chiral distortions, characterized by defining a pseudo-scalar quantity, ( represents the ferroelectric displacement vector and denotes the ferro-rotational vector), which distinguishes between (R)- and (S)-chirality based on its sign. Moreover, the reversal of this descriptor's sign can be associated with coordinated transitions in ferroelectric distortions, Jahn-Teller antiferro-distortions, and Dzyaloshinskii-Moriya vectors, indicating the mediating role of crystallographic chirality in magnetoelectric correlations.

Plotting a New Course for Environmental Humanities

Abstract This article suggests that the notion of “the plot” has methodological and epistemological value for the environmental humanities. Conceptualized in the work of Sylvia Wynter, the plot—as material site and narrative mode crucial to the novel form—offers a heuristic for analyzing the conjuncture of political economy, social-cultural aesthetics, and power. The plot names places that have been created through improvisational forms of world-making against racial and socioecological domination. The plot also names an insurgent scheme that is staged from peripheralized places and that is crucial to maintaining these spaces of insurgent living. Plotting is presented as an analytical mode that offers scholars in the environmental humanities: a framework for place-specific historical-geographical and ecological study; a critical cartographical praxis; and an approach for examining the logics and affective relations of place production. Environmental humanities scholarship that engages with Black ecocriticism along these lines is well positioned to examine the geographies of the past, present, and future with attention to the racial politics of human embodiment. Such scholarship would be characterized by more careful use of spatial metaphors, ensuring that ecocriticism and broader environmental humanities work considers the material and physical racial ecologies alongside the discursive and representational environments.

Towards Functionality and Deactivation of Metal-Single-Atom in Heterogeneous Photocatalysts.

Single-atom heterogeneous catalysts (SAHCs) provide an enticing platform for understanding catalyst structure-property-performance relationships. The 100% atom utilization and adjustable local coordination configurations make it easy to probe reaction mechanisms at the atomic level. However, the progressive deactivation of metal-single-atom (MSA) with high surface energy leads to frequent limitations on their commercial viability. In this review, we focus on the atomistic-sensitive reactivity and atomistic-progressive deactivation of MSA to provide a unifying framework for specific functionality and potential deactivation drivers of MSA, thereby bridging function, purpose-modification structure-performance insights with the atomistic-progressive deactivation for sustainable structure-property-performance accessibility. We first systematically explore the dominant functionalization of atomically precise MSA acting on properties and reactivity encompassing precise photocatalytic reactions. Afterwards, a detailed analysis of various deactivation modes of MSA and strategies to enhance their durability are presented, providing valuable insights into the design of SAHCs with deactivation-resistant stability. Finally, we complete with a look into the remaining challenges and future perspectives of SAHCs towards industrialization, anticipating shedding some light on the next stage of atom-economic chemical/energy transformations. This article is protected by copyright. All rights reserved.

The β Pictoris b Hill sphere transit campaign

The β Pictoris system is the closest known stellar system with directly detected gas giant planets, an edge-on circumstellar disc, and evidence of falling sublimating bodies and transiting exocomets. The inner planet, β Pictoris c, has also been indirectly detected with radial velocity (RV) measurements. The star is a known δ Scuti pulsator, and the long-term stability of these pulsations opens up the possibility of indirectly detecting the gas giant planets through time delays of the pulsations due to a varying light travel time. We search for phase shifts in the δ Scuti pulsations consistent with the known planets β Pictoris b and c and carry out an analysis of the stellar pulsations of β Pictoris over a multi-year timescale. We used photometric data collected by the BRITE-Constellation, bRing, ASTEP, and TESS to derive a list of the strongest and most significant δ Scuti pulsations. We carried out an analysis with the open-source python package maelstrom to study the stability of the pulsation modes of β Pictoris in order to determine the long-term trends in the observed pulsations. We did not detect the expected signal for β Pictoris b or β Pictoris c. The expected time delay is 6 s for β Pictoris c and 24 s for β Pictoris b. With simulations, we determined that the photometric noise in all the combined data sets cannot reach the sensitivity needed to detect the expected timing drifts. An analysis of the pulsational modes of β Pictoris using maelstrom showed that the modes themselves drift on the timescale of a year, fundamentally limiting our ability to detect exoplanets around β Pictoris via pulsation timing.

Thermoeconomic assessment of the air-cooled tropical data center through energy-saving strategies

Rapid developments in the electronic information industry drive the increased energy usage and carbon emission of data center buildings, prompting the focus on the energy efficiency and environmental sustainability. Expanded operation envelopes of tropical data centers is assessed to analyze the potential for the building energy savings and carbon emission reduction through collaborative analysis of operation modes (OMs), supply air temperature (SAT), and outdoor air temperature (OAT). The OMs of compression vary with the setpoints of SAT, in which the average exergy efficiency of compressors at alternate operation mode is 6.8 % and 8.0 % lower than that of double and single compression operations. As SAT rises from 20 °C to 32 °C, the system exergoeconomic factor increases from 5.4 % to 8.0 %, and the average carbon cost decreases by 36.5 %. Additionally, with just an 8.5 % increase in exergy cost (i.e., Case 8) at OAT rising from 30 to 34 °C, the high SAT and low refrigerant charges provide considerable exergy cost advantages versus resisting the OAT fluctuations. Dynamic operation strategies are also proposed and compared to cope with the impacts of tropical environments. Compared to the 26 °C SAT baseline, the average energy savings are 9.1–14.7 %, indicating the ability to fully utilize outdoor and indoor conditions.

Thermal transport and topological analyses of the heat-carrying modes and their relevant local structures in variously dense amorphous alumina

Engineering the thermal conductivities of amorphous materials is important for thermal management of various semiconducting devices. However, controlling the heat carriers—long-range propagating propagons and short-range hopping diffusons—in disordered lattices is difficult because the carriers are strongly correlated with lattice disorder. To clarify the relationship between lattice disorder and heat conduction, we must simultaneously investigate the important local structures hidden in a disordered system and the microscopic transport characteristics of propagons and diffusons. Here, we explore the variations in spectral thermal conductivity and the relevant local structures in amorphous alumina (a-Al2O3) at different densities by performing the spectral thermal transport and persistent homology analyses. As the density increases, the thermal conductivity of the high-frequency diffusons linearly increases but those of the propagons and low-frequency diffusons remain constant. The density increase enhances the local strain, thereby increasing the mean free paths of the high-frequency diffusons. The density of states competes with diffusivity, lowering the sensitivity of the density response to the thermal conductivity of low-frequency heat carriers. Furthermore, from the obtained topological features of the connections between the oxygen atoms, we inferred that the collapsed network of six-coordinated AlO6 octahedron clusters underlies the transport of high-frequency diffusons. Besides revealing the conductive pathways of heat-carrying modes in disordered lattices, topology-assisted spectral thermal transport analysis is useful for tailoring the thermal conductivities of amorphous materials.

Implementation of Failure Mode and Effect Analysis (FMEA) for centrifugal pump maintenance in water supply distribution system

A centrifugal pump is an essential mechanical device in the Regional Drinking Water Company (PDAM) to distribute sterile water from the reservoir to local community houses by flowing the fluid through the pipeline. However, improper and inadequate maintenance of centrifugal pumps can result in component damage, including bearings that are broken, ripped, or damaged mechanical seals. Therefore, for the water supply to continue smoothly, proper maintenance needs to be carried out so that the engine's performance will be maintained and last longer. This study aims to conduct a maintenance analysis on centrifugal pumps utilized by the PDAM of Madiun City. The Failure Modes and Effects Analysis (FMEA) method was employed to assess the potential failure of a system, design, process, or service by implementing a systematic approach to analyze damage and devise maintenance strategies. The FMEA analysis revealed that the shaft of the centrifugal pump component had the highest Risk Priority Number (RPN) value, which amounts to 294. The wearing ring had the lowest RPN value among the centrifugal pump components, with a value of 54. The Pareto diagram results classified six components: shaft, clutch, stuffing box, motor, impeller, and mechanical seal to recommend preventative maintenance action. Additionally, three other components suggested for corrective maintenance were the bearing, packing, and wearing rings

Modulation of Solid-State Fluorescence Properties for Anthracene Chalcone Heterocyclic Compounds by Charge-Transfer Cocrystal Self-Assembly: Molecular Stacking Mode and DFT Analysis

Modulation of Solid-State Fluorescence Properties for Anthracene Chalcone Heterocyclic Compounds by Charge-Transfer Cocrystal Self-Assembly: Molecular Stacking Mode and DFT Analysis

Quantifying the Risk of Technology-Driven Health Disparities in Radiation Oncology

PurposeNew technologies are continuously emerging in radiation oncology. Inherent technological limitations can result in healthcare disparities in vulnerable patient populations. These limitations must be considered for existing and new technologies in the clinic to provide equitable care. Materials and MethodsWe created a health disparity risk assessment metric inspired by failure mode and effects analysis (FMEA). We provide sample patient populations and their potential associated disparities, guidelines for clinics and vendors, and example applications of the methodology. ResultsA disparity risk priority number (dRPN) can be calculated from the product of three quantifiable metrics: the percent of patients impacted (P), the severity of the impact of dosimetric uncertainty or quality of the radiation plan (S), and the clinical dependence on the evaluated technology (C). The dRPN can be used to rank the risk of sub-optimal care due to technical limitations when comparing technologies and to plan interventions when technology is shown to have inequitable performance in the patient population of a clinic. ConclusionThe proposed methodology may simplify the evaluation of how new technology impacts vulnerable populations, help clinics quantify the limitations of their technological resources, and plan appropriate interventions to improve equity in radiation treatments.

Safety and efficiency of a fully automatic workflow for auto-segmentation in radiotherapy using three commercially available deep learning-based applications

Advancements in radiotherapy auto-segmentation necessitate reliable and efficient workflows. Therefore, a standardized fully automatic workflow was developed for three commercially available deep learning-based auto-segmentation applications and compared to a manual workflow for safety and efficiency. The workflow underwent safety evaluation with failure mode and effects analysis. Notably, eight failure modes were reduced, including seven with severity factors ≥7, indicating the effect on patients, and two with Risk Priority Number value >125, which assesses relative risk level. Efficiency, measured by mouse clicks, showed zero clicks with the automatic workflow. This automation illustrated improvement in both safety and efficiency of workflow

Collision between supply vessels and offshore installations case cargo handling and personal transferring operation

Abstract This paper presents a systematic methodology aiming at investigating human-error induced collisions between attendant vessels and offshore installations, with focus on three key risk categories: Cargo handling and personnel transferring (CH), loss of station keeping (SK) and ship handling and maneuvers (SH). Because of space limitation, the methodology will be applied here to the first category (CH) only. The Failure Mode, Effects and Criticality Analysis (FMECA) method was used to identify the hazards. Moreover, the Interpretive Structural Modeling (ISM) of Multi Criteria Decision Making (MCDM) was used for the same purpose and results of both methods were favorably compared. Moreover the Fault Tree Analysis (FTA) was used to evaluate the root causes of accidents down to the Underling Factors (UFs) benefiting from the revised guidelines for the IMO Formal Safety Assessment (FSA).