Design Criteria Research Articles

Probabilistic Approach for Q-based Ground Support Design

For tunnel, cavern, and shaft design, the inherent variability in a given rock mass domain makes accurately estimating rock mass quality and support requirements difficult. To capture the variability in rock mass properties when using the Q system, a methodology incorporating a statistical analysis of measured Q input parameters and Monte Carlo Simulation was developed to perform a probabilistic ground support design approach. Probability and cumulative density function curves were then developed using the mathematical program MATLAB to guide in estimating ground support based on all potential rock mass conditions. To illustrate the proposed approach, two hypothetical tunnels were designed based on real data from two previous projects. Finite Element Modelling was used to evaluate the suggested Q rock support performance in a range of rock conditions for one of the hypothetical excavations to validate the proposed approach. This method demonstrated that associating a range of potential ground conditions instead of a single deterministic value for each input parameter can provide a quantifiable measurement of uncertainty within a given rock mass domain. Additionally, the approach provides insight into the design criteria for ground support in underground excavations to potentially reduce overly conservative and costly recommendations.

Analysis and Evaluation of Artificial Lighting in the Passenger Spaces of a 500 Gt Ro-Ro Ferry

Lighting is an important design criterion for ships, including the ro-ro ferry. The ship’s lighting system must meet certain standards. Therefore, the present study analysed and evaluated the artificial lighting of an Indonesian ro-ro ferry. The analysed ship in the present research was a 500 GT ro-ro ferry named KMP. Takabonerate that operated across the Selayar Islands of Indonesia. The artificial lighting systems in this ship’s three passenger spaces, which are reclining seat room, sofa seat room, and passenger open space, were evaluated and analysed. The main parameter to be investigated was the room illuminance produced by the ship’s lighting system. In order to achieve the study objective, the illuminance in those rooms was calculated using analytical formulas. The calculation results were validated using direct measurements and computer simulation. The direct measurements were conducted using a luxmeter, while computer simulations were performed using DIAlux Evo 10.0 software. With this software, the artificial lighting in the passenger spaces was also simulated and realistically visualized. The research results showed that the illuminance in the reclining seat room and the sofa seat room had met the minimum illuminance value set by the Indonesian National Standard (SNI), American Bureau of Shipping (ABS), and Indonesian Classification Bureau (BKI) standards. For the passenger open space, a re-arrangement of the lighting system was conducted to improve the light distribution so that all space illumination can meet the specified standards.

Research on the measurement mechanism of a six-axis force sensor based on a flexible hinge series–parallel hybrid

Abstract Addressing the common limitations of current six-axis force sensors, including the degradation of strain gauge accuracy due to environmental influences and the necessity for a complete replacement when damaged, this paper proposes an innovative six-axis force sensor that integrates a hybrid serial–parallel structure featuring flexible hinges. The sensor’s bracket is designed using a combination of serial–parallel flexible hinges, which confer load distribution capabilities, are lightweight, have high strength, and facilitate replacement. The static force model and the overall stiffness model of the sensor were developed based on the 3-universal–prismatic–universal parallel mechanism theory, providing a theoretical foundation for evaluating the sensor’s performance. To validate the accuracy of the stiffness model, finite element software is utilized for simulation-based verification. Subsequently, a calibration experiment is performed on the sensor, yielding results that conclusively show an error margin of less than 5% between experimental and theoretical values, satisfying the design criteria for sensor measurement.

Development and Validation of the MAST ISOPLEX®VTEC Kit for Simultaneous Detection of Shiga Toxin/Verotoxin 1 and 2 (stx1/vt1 and stx2/vt2) with Inhibition Control (IC) in a Rapid Loop-Mediated Isothermal Amplification (LAMP) Multiplex Assay.

Loop-mediated isothermal amplification (LAMP) is a cost-effective, rapid, and highly specific method of replicating nucleic acids. Adding multiple targets into a single LAMP assay to create a multiplex format is highly desirable for clinical applications but has been challenging due to a need to develop specific detection techniques and strict primer design criteria. This study describes the evaluation of a rapid triplex LAMP assay, MAST ISOPLEX®VTEC, for the simultaneous detection of Shiga toxin/verotoxin 1 and 2 (stx1/vt1 and stx2/vt2) genes in verotoxigenic Escherichia coli (E. coli) (VTEC) isolates with inhibition control (IC) synthetic DNA using a single fluorophore-oligonucleotide probe, MAST ISOPLEX®Probes, integrated into the primer set of each target. MAST ISOPLEX®Probes used in the MAST ISOPLEX®VTEC kit produce fluorescent signals as they integrate with reaction products specific to each target, allowing tracking of multiple amplifications in real time using a real-time analyzer. Initial validation on DNA extracts from fecal cultures and synthetic DNA sequences (gBlocks) showed that the MAST ISOPLEX®VTEC kit provides a method for sensitive simultaneous triplex detection in a single assay with a limit of detection (LOD) of less than 100 target copies/assay and 96% and 100% sensitivity and specificity, respectively.

Design Rules for Capillary Force-Induced Clustering and Recovery of Monolithic Microbridges on Microapertured Polymer Membrane.

Microbridge structures have been widely used in microelectromechanical systems. When the devices with microbridges operate in diverse environments, including wet conditions, structural failures such as crumples, clustering, and collapse of micro/nanostructures occur due to the capillary force of liquid in this environment. It is necessary to establish comprehensive design criteria to address this. Herein, we investigate the structural stability of microbridges on microsized apertures in wet conditions. The multiscale structure is fabricated with microbridge width, spacing of 10 μm, and height of 6 μm while varying the supporting micro aperture size. The behavior of the microbridges is observed through an optical microscope during water dispensing on the bridges and evaporation. It is found that the microbridges remain stable on apertures of 100 μm in diameter, while clustering occurs on larger-sized apertures (300, 500 μm). Interestingly, in contrast to the 500 μm-sized aperture, the clustered microbridges on the 300 μm-sized aperture gradually recover to their original configuration after completely evaporating water. A simple theoretical model for capillary force-induced clustering and recovery is proposed to elucidate this phenomenon, which agrees with the experimental results. The microbridges constructed following the design rule can ensure robust and stable operation even in wet conditions. These findings contribute to advancing micro/nanoscale engineering and offer insights for developing innovative microdevices.

Dynamic Characteristics of a 1950s Heritage Building: A Comparison of Original Design Methods and Modern Techniques

Research on design rules and methods for architectural heritage is an important aspect of conservation practice. Nevertheless, efforts to recover and divulge design methods for Modern Heritage remain limited. This paper is related to the recent structural assessment of a 15-storey heritage building built in 1950, during which a document describing the original seismic analysis of this structure was identified. The methodology employed is of particular interest, as it involves the application of pioneer concepts of dynamic analysis in the design of the first tall buildings in Mexico. The primary aim of this paper is to review the seismic design criteria for the case under study in order to contribute to the state of the art in Modern Heritage. The review includes a comparison between the dynamic characteristics estimated during the design and the results of recent ambient vibration tests and numerical modeling. Several sources of error among the design criteria were identified. Notably, the fundamental period estimated during the design was 38% larger than the experimental value due to an underestimation in stiffness, which introduces significant uncertainty into the design. Overall, the review shows the evolution of seismic analysis over time and provide valuable insights for the study of similar buildings.

Impact of damaged housing on the performance of field aged composite High Voltage Insulators

Composite High Voltage Insulators (HVIs) are lightweight, inexpensive, and offer superior pollution performance. Consequently, they have replaced ceramic HVIs in highly contaminating coastal and desert regions. However, they are prone to degradation in harsh environments. In this paper, we assess the performance of three identical field-aged 380 kV composite HVIs with a service life of twelve years near the western coastal region of the Kingdom of Saudi Arabia. The housing of all the HVIs showed widespread damage, including cracks on sheds and shanks, partially or fully broken sheds, and rusted end fittings. The changes in morphology and material composition were assessed through SEM and EDX. An electrical breakdown test in the presence of steam fog revealed lowered withstand strength. Electric field distribution, a key design criterion for an HVI, was studied using the Finite Element Model (FEM) of the insulator bearing physical defects. The results reveal localized electric field intensification caused by all types of defects, notably smaller and narrower ones. Our findings indicate that while physical defects in HVIs can cause localized electric field intensification, they are not a significant concern unless accompanied by severe hydrophobicity loss, compromised electrical withstand levels, or extensive erosion exposing the fiberglass rod and jeopardizing mechanical stability.

Heritage, urban form and spatial resignification in the production of sustainable Olympic legacies: an urban design analysis of the Rio de Janeiro Olympic Games

The Olympic Games have been associated with many urban transformation projects throughout their history, often focusing on city expansion. Recent sustainability concerns, however, constitute a pressing challenge, with the regeneration of central areas fulfilling a key role in existing urban agendas. In this paper, the legacy of the Rio 2016 Olympic Games at two proposed centralities was analysed, namely, the Olympic Park, intended as a future neighbourhood to the west of the city, and Porto Maravilha (PM), an urban project aimed at revitalizing a central, historical area of the city. By comparing the Olympic Park and the first provided areas in PM, in terms of selecting urban design criteria through qualitative in loco assessments, this paper focused on analysing the impacts of urban forms and heritage on the consolidation of these two centralities, as well as encouraging social interaction and integration into the city. The analysis results indicated that urban design attributes such as human-scaled, mixed-use, context-based urban spaces could interfere with social interaction and the usability of spaces. Moreover, the repurposing of heritage buildings contributed to urban cohesion for legacy transformation. Hence, novel insights into urban design and heritage could become important for future editions of the Olympics so that host cities may fulfil their sustainability agendas.

Efficiency of Bevel and Hypoid Gears—Test Rig Development and Experimental Investigations

The efficiency of bevel and hypoid gears is, alongside load capacity, one of their most important design criteria. To consider the efficiency of bevel and hypoid gears during the development and design process, validated calculation methods based on experimental investigations are necessary. However, the isolated experimental investigation of the load-dependent power losses of bevel and hypoid gears has not been adequately investigated, as most of the experimental investigations consider the complete gearbox. This paper presents a test rig that allows for the experimental investigation of the efficiency of bevel and hypoid gears with a measurement uncertainty of the efficiency of ∆η≤±0.08% according to the Guide to the Expression of Uncertainty in Measurement (GUM). Using the developed test rig, experimental investigations on the efficiency behavior of bevel and hypoid gears regarding the influence of the axial offset, driving direction, and microgeometry are carried out for different operating points varying in circumferential speed and load. This paper discusses the methodology and the first experimental results of a study on the efficiency of bevel and hypoid gears in detail.

Similarity design method and multi-objective optimization of train energy-absorbing tube velocity distortion under axial impact

Thin-walled tubes are commonly used as crucial structures for energy absorption. It is an efficient and convenient research method to establish a small-scale model of the energy-absorbing thin-walled tube for experiments. However, due to the inevitable difference between the design velocity of the test and the actual velocity of the test, it cannot meet the traditional similarity theory. Because of this limitation, this article constructs a similarity design method for the velocity distortion of the multi-cell energy-absorbing tube at the front end of the train under axial impact. Firstly, according to the motion equation of the train system, the design criterion of the similar model under the velocity distortion is derived. Then, the collision mass correction factor is derived based on the elastic-plastic structural energy equation, aiming at the error of the collision peak force and the error of the collision time, the correction factor of the wall thickness of the energy absorbing tube is obtained based on the simulation analysis results. Finally, it is verified that the velocity distortion similarity model can accurately predict the dynamic response of the prototype, and reveals the influence of the mass and wall thickness correction factors on the error.

Operando electron spin probes for the study of battery processes

Operando electron spin probes, namely magnetometry and electron paramagnetic resonance (EPR), provide real-time insights into the electrochemical processes occurring in battery materials and devices. In this work, we describe the design criteria and outline the development of operando magnetometry and EPR electrochemical cells. Notably, we show that a clamping mechanism, or springs, are needed to achieve sufficient compression of the battery stack and an electrochemical performance on par with that of a standard Swagelok-type cell. The tandem use of operando EPR and magnetometry allows us to identify five distinct and reversible redox processes taking place on charge and discharge of the intercalation-type LiNi0.5Mn0.5O2 Li-ion cathode. While redox processes in conversion-type electrodes are notoriously difficult to investigate using standard characterization methods (e.g. X-ray based) and/or post mortem analysis, due to the formation of poorly crystalline and metastable reaction intermediates and products during cycling, we show that operando magnetometry provides unique insight into the kinetics and reversibility of Fe nanoparticle formation in the Na3FeF6 electrode for Na-based batteries. Step increases in the cell magnetization upon extended cycling indicate the build-up of Fe nanoparticles in the system, hinting at only partially reversible charge–discharge processes. The broad applicability of the tools developed herein to a range of electrode chemistries and structures, from intercalation to conversion electrodes, and from crystalline to amorphous systems, makes them particularly promising for the development of electrochemical energy storage technologies and beyond.

Proposal of a Creep-Experiment Method and Superficial Creep Coefficient Model of CFT Considering a Stress-Redistribution Effect

Existing concrete creep coefficient prediction models have the limitation of not considering the structural characteristics of CFT. For this reason, these models tend to overestimate the creep deformation of CFT. Therefore, in order to overcome the limitations of existing CFT creep experiments, this study proposes a creep-experiment method involving the use of CFT that passively changes the load applied to a single concrete specimen by calculating the stress redistribution between the concrete and a steel tube in CFT based on a step-by-step method. Furthermore, by actually applying the proposed experimental method, a creep experiment of CFT lasting for approximately 163 days was performed and a superficial creep coefficient model of CFT was proposed based on long-term strain data from the experiment. In order to verify the proposed superficial creep coefficient model, it was compared with two design criteria (CEB-FIP and ACI) based on the experimental results of this study and references. As a result, compared to the existing design criteria, the value predicted by the proposed superficial creep coefficient model showed good agreement with the experimental results of this study and the references, proving that the proposed creep-experiment method of CFT and superficial creep coefficient model are reasonable.

Design and modeling of a programmable morphing structure with variable stiffness capability

The development of structures capable of both dynamic shape morphing and stiffness modulation has significant potential in various applications. However, such structures often suffer from bulkiness and control complexity. This paper addresses these challenges by exploring a scaled structure that integrates morphing capabilities and variable stiffness within a compact configuration. For the first time, we establish a comprehensive set of design criteria and obtain the previously unexplored design space, focusing on geometric parameters including layer thickness, target shape radius, the number of scales, and the number of periods per scale. Through extensive finite element simulations, we evaluate the impact of material property and geometric parameters on the performance of the scaled structure, emphasizing the role of coefficient of friction. Our findings identify a critical threshold for the coefficient of friction above which morphing ability is hindered. Additionally, we uncover a trade-off between morphing capability and stiffness variation ability, which we overcome by modifying the surface structure of the scales. The optimal design is found to be a superellipse shape with an exponent of ∼1.9. The practical potential of this structure is demonstrated through three applications: a soft gripper, a phone stand, and a foldable box, showcasing its versatility in real-world scenarios. This research provides a foundational approach for designing morphing scaled structures, offering valuable insights into optimizing morphing capability and stiffness variation ability for broader engineering applications.

Cumulative incidence of chronic health conditions recorded in hospital admissions from birth to age 16 in England: a cohort study using linked hospital and education administrative data

ObjectiveMonitoring the incidence of chronic health conditions (CHCs) in childhood in England using administrative data to derive numerators and denominators is challenged by unmeasured migration. We used a birth cohort design and different criteria for contact with health or education services to estimate the cumulative incidence of CHCs to age 16 years. ApproachWe identified all births in Hospital Episode Statistics (HES) from 2002/3 to 2011/12, with follow-up to 2018/19 (maximum age 8 to 16 years), censoring on death, first non-England residence record or 16th birthday. Children must have linked to later HES records and/or the National Pupil Database (NPD), which provides information on all state-school enrolments. The cumulative incidence of CHCs was estimated to age 16 using diagnostic codes in hospital admission records. We also explored temporal variation. Sensitivity analyses varied denominator criteria. ResultsBetween 423,456 children (79.4%, of all HES-recorded births in 2002/3) and 618,054 (97.5% in 2011/12) linked to later HES or NPD records. The cumulative incidence of ever having a recorded CHC before age 16 among children born in 2002/3 or 2003/4 was 24.6%, ranging from 21% to 32% in sensitivity analyses. There was little temporal variation. At least 28% of children with any CHC had more than one body system affected by age 16. Multimorbidity rates rose with later cohorts. ConclusionsApproximately one quarter of children are affected by CHCs, but varies depending on how the denominator is defined. More accurate estimation of the incidence of CHCs requires a dynamic population estimate.

Adaptive Operating Rules for Flood Control of a Multi-Purpose Reservoir

Almost all multipurpose reservoirs in Romania were put into operation 30–50 years ago or even earlier. Meanwhile, a large volume of hydrologic data has been collected, and the initial design flood should be reconsidered. Consequently, the operating rules of flow control structures (bottom gates and weir gates) should be re-examined, mainly for medium and low-frequency floods. The design flood is not unique, being characterized by different shapes and time to peak, which has consequences for flood mitigation rules. Identifying the critical design flood is an important preliminary step, although it is usually neglected in flood management. Simulating the operation of the Stânca–Costești reservoir on the Prut River, it was found that the design flood corresponding to the maximum value of the compactness coefficient is the most difficult to mitigate considering the specific conditions of the dam and the reservoir: the prescribed conservation level in the reservoir, and the design flood volume of medium and rare floods that far exceeds the flood control volume. These conditions can jeopardize both dam safety and downstream flood protection. The main steps of the proposed approach are as follows: (1) developing the hydraulic model; (2) statistical processing of the registered floods and defining critical design floods for different AEPs (Annual Exceedance Probabilities); (3) deriving optimal operation rules based on a simulation-optimization model; (4) implementing real-time adaptive operation of the mechanical outlets; and (5) critically assessing the operating rules after the event. Based on the hydrological forecast, if necessary, new outlets are put into operation while keeping the ones already activated. Based on the hydrological forecast and properly operated, the safety of the Stânca–Costești dam is guaranteed even in the event of a 0.1% CC (Climate Change) flood. However, for floods greater than 1% magnitude, the carrying capacity of the downstream riverbed is exceeded. The main gaps addressed in this paper are the following: (1) the establishment of critical design floods, and (2) the adaptive operating rules of outlet devices aimed at optimizing flood control results, using short-term flood forecasts.

Research on the Jet Distance Enhancement Device for Blueberry Harvesting Robots Based on the Dual-Ring Model

In China, most blueberry varieties are characterized by tightly clustered fruits, which pose challenges for achieving precise and non-destructive automated harvesting. This complexity limits the design of robots for this task. Therefore, this paper proposes adding a jetting step during harvesting to separate fruit clusters and increase the operational space for mechanical claws. First, a combined approach of flow field analysis and pressure-sensitive experiments was employed to establish design criteria for the number, diameter, and inclination angle parameters of two types of nozzles: flat tip and round tip. Furthermore, fruit was introduced, and a fluid–structure coupling method was employed to calculate the deformation of fruit stems. Simultaneously, a mechanical analysis was conducted to quantify the relationship between jet characteristics and separation gaps. Simulation and pressure-sensitive experiments show that as the number of holes increases and their diameter decreases, the nozzle’s convergence becomes stronger. The greater the inclination angle of the circular nozzle holes, the more the gas diverges. The analysis of the output characteristics of the working section indicates that the 8-hole 40° round nozzle is the optimal solution. At an air compressor working pressure of 0.5 MPa, force analysis and simulation results both show that it can increase the picking space for the mechanical claw by about 5–7 mm without damaging the blueberries in the jet area. The final field experiments show that the mean distance for Type I (mature fruit) is 5.41 mm, for Type II (red fruit) is 6.42 mm, and for Type III (green fruit) is 5.43 mm. The short and curved stems of the green fruit are less effective, but the minimum distance of 4.71 mm is greater than the claw wall thickness, meeting the design requirements.

Pre-cooling systems in modern hydrogen liquefaction

The research work presents recommendations for choosing a circuit design for low-capacity hydrogen liquefaction plants with a production rate up to 20 kg/h or 0,48 tpd (ton per day). Main design criteria considered are specific energy cost, as well as capital costs and overall characteristics of the system. A review of theoretical and real hydrogen liquefaction cycles is presented. Mathematical models of different circuits are built up considering real parameters of the typical equipment. The advantages and disadvantages of certain solutions are identified, efficiency trends in terms of hydrogen liquefaction plants are analysed. According to the obtained results of the research main of the circuits for low-capacity hydrogen liquefaction plants are selected.

Beyond Technical Specs: Using AHP to Prioritize User Needs in Turkish Basketball Arena Designs

Basketball arenas are crucial spaces that must meet specific standards to ensure the sustainability of the sport and the quality of play. While Post-Occupancy Evaluation (POE) assesses these standards, it often assumes that all performance indicators are equally important, potentially leading to a gap between design intent and actual user experience. This study aims to bridge this gap by using the Analytic Hierarchy Process (AHP) to prioritize evaluation criteria for Turkish professional basketball arenas designed for national and international matches, regional/local competitions, and training programs. Existing studies and reports indicate that basketball arenas in Turkey often fall short in meeting necessary physical requirements and exhibit performance deficiencies. To address this gap, this study identifies factors determining arena performance, categorized as technical, functional, and behavioral based on Preiser's framework. These criteria were further categorized according to different spaces within the arena, including general use areas, administrative spaces, and athlete-specific areas. A panel of expert sports facility design professionals provided judgments about the relative importance of these criteria using pairwise comparisons. The AHP method was then employed to calculate priority weights for each criterion. The results reveal the relative importance of different criteria for each space. For example, in general use areas, "furniture suitability/sufficiency" and "provision of ergonomic conditions for the disabled" ranked highest. In administrative spaces, "fire protection" and "accessibility" were deemed most important, while in athlete-specific areas, "visual and auditory privacy" and "security" took precedence. This study demonstrates the potential of AHP for developing a systematic and reliable framework for qualitative evaluations that measure user satisfaction. AHP-based evaluation models offer a valuable tool for architects, facility managers, and decision-makers to assess architectural design quality, prioritize design criteria, and support user-centered design processes.

The past and present of thought experiments’ research at Glancy: bibliometric review and analysis

In the development of physical theories, thought experiments play a crucial role. Research on this topic began in 1976 and has continued to the present. This study aims to provide a more complete picture of the progress of thought experiments over the past two decades. To achieve this, this study employs bibliometric mapping methods. A total of 679 published papers were analyzed, including articles (504), conference papers (92), and book chapters (83). This data was retrieved from the Scopus database. The study's findings reveal that research and publications on thought experiments are highly valued and have received significant attention over the past eight years. According to the findings, 90% of the top 20 source titles contributing to thought experiments are from journals in the first and second quartiles (Q1 and Q2). This quartile ranking shows the quality and significant influence of a journal. The geographical distribution indicates that the United States contributes the most to thought experiments research, with 213 documents, 2592 citations, and 47 links. We also identified several prospective keywords that could be the focus of future research, including artificial intelligence, physics education, fiction, God, theology, productive imagination, technology, speculative design, and critical design. Therefore, this study provides a thorough picture of thought experiment research trends and future directions of potential topics that can be the focus of future researchers.

A Systematic Approach towards the Integration of Initial Airworthiness Regulatory Requirements in Remotely Piloted Aircraft System Conceptual Design Methodologies

The regulatory framework of Remotely Piloted Aircraft Systems (RPASs) has recently experienced an extraordinary evolution. This article seeks to improve the integration of certification considerations in RPAS conceptual design approaches so as to enhance the safety, certifiability and competitiveness of their resulting designs. The first part of the research conducts a two-stage analysis of contemporary regulations related to an RPAS’s initial airworthiness. In the first stage, the broad international regulation paradigm is evaluated attending to a set of criteria that are tightly related to both airworthiness and design considerations. The second stage keeps the most promising documents from a design–integration standpoint, which are assessed according to their applicability considering both design and operational aspects. The results of this analysis provide insights regarding the main issues in airworthiness design criteria extraction and integration in design methodologies. To aid the designer in surmounting these challenges, a flexible procedure named DECEX is developed. Considering the documents and findings from the survey, and attending to the scope of the design methodology being developed, it aids in establishing a complete regulatory document corpus and in comparing and extracting the applicable airworthiness design criteria. Two case studies for different RPAS types are conducted to demonstrate its application.