model-based radiostereometric analysis (RSA) randomized control trial evaluating the stability of the cementless Taperloc hip stem: the TapHip study

Background and purpose – The Taperloc Complete hip is the successor of the Taperloc hip, aiming to increase range of motion and optimizing femoral fit with intermediate stem sizes. We evaluated whether these design changes affect fixation, and this RSA study compares 2-year migration. Patients and methods – In this prospective, multi-arm study, 100 patients were randomized to cementless total hip arthroplasty (THA) with Taperloc Complete full profile (TCFP), Taperloc Complete reduced distal (TCRD), Taperloc full profile (TFP), or Taperloc reduced distal (TRD). Migration was measured with model-based RSA postoperatively, and after 3, 12, and 24 months. Results – Results based on mixed-model analysis on 2-year postoperative RSA data from 74 patients showed similar subsidence (mm) in the first 3 months (mean [95% CI] TCFP 0.44 [0.20–0.69], TCRD 0.91 [0.40–1.42], TFP 0.71 [0.22–1.19], TRD 1.25 [0.58–1.91]) and stabilization afterwards. The TCFP showed statistically significantly less retroversion (°) at 2-year postoperatively compared with TFP and TCRD (mean [95% CI] TCFP: –0.13 [–0.64 to 0.38], TCRD: 0.84 [0.35–1.33], TFP: 0.56 [0.12–1.00], TRD: 0.37 [–0.35 to 1.09]). Interpretation – As expected in successful cementless THA, RSA shows stabilization after initial subsidence. Based on these results the Taperloc Complete stem is expected to have similar long-term fixation to the Taperloc stems. The reduced distal groups have larger, but statistically non-significant, initial migration compared with the TCFP group, which could be due to implantation in Dorr B, C femur types. It may be important to consider the femur shape for choosing a full profile or reduced distal stem to minimize migration.

Knowledge Based Engineering for Hydrogen Gas Turbines and Burners Design: a review

Hydrogen gas turbines and burners need high attention and their appropriate realization, yet during their design, can lead important benefits for the whole sector. Realizing the best design, the first time, reduces reworks and requests of design changes from the manufacturing departments. In this field, Knowledge Based Engineering is a good strategy for embedding, in an automatic way, experts’ knowledge into CAD models during the design of a component. It enables a reduction of human errors and costs in several design tasks and improving the final quality of a component model. With these premises, the aim to the study is to lead improvements and appropriate actions in the design and re-configuration of hydrogen power generation systems (i.e. gas turbines and burners) by means of KBE, leading improvements yet in this early phase of the global race for hydrogen. A systematic literature review is carried out to explore the current state of art for the application of KBE for the design of turbines and burners in different industrial sectors. Evidences from the practice are collected in a structured classification and elaborated and summarized for application in the design of gas turbines and burners for the hydrogen production.

Optimized High Precision Stacking of Fuel Cell Components for Medium to Large Production Volumes

PEM fuel cells are well established in a number of niche markets. However, due to low production volume and manufacturer-specific designs, the assembly has been carried out manually most of the time. With new fields of application being exploited there is a rising demand for production systems. As there is no standardized design or material, production systems are often custom-made, thus being inflexible to design changes or different products. In combination with a volatile demand the need for flexible and scalable systems arises. In this paper special attention is paid onto pick and place operations of the catalyst coated membrane (CCM). Design criteria of a vacuum gripper are derived from the material properties. To meet the further requirements for a high position accuracy in an automated assembly the impact of process parameters onto the repeatability is investigated to identify optimization trends. The requirements and investigations lead to a conceptual assembly system that is able to cover several steps in fuel cell production.

Research of the modernized intake system of the gasoline engine

Problem. In recent years, Ukraine has seen a sharp decline in ambient temperature, especially in the winter. Accordingly, this has a negative impact on the performance of car engines (difficult to start and prolonged warm-up), as the lion's share of private sector cars are parked in open areas and are subject to sudden temperature and humidity changes. Therefore, to partially solve this problem, our attention was focused on the air lines of the intake system of the gasoline engine, as this system is easily accessible and does not require significant design changes for its modernization. Goal. The purpose of the work is to ensure the ease of starting the gasoline engine and reduce the time to warm up. Methodology. Operation of the car in the conditions of the lowered temperatures, essentially promotes deterioration of its fuel economy. The basis of such a negative process of fuel consumption is incomplete combustion of the working mixture. And this is the deterioration of spraying and evaporation of fuel and increasing the duration of engine warm-up. At such low ambient temperatures, the effective operation of the car in a garage depends significantly on the method of its preparation (which should at a minimum cost of fuel and energy resources to ensure rapid and reliable engine start and accelerated warm-up). We decided to obtain thermal energy to heat the inlet air at no additional cost. This is the installation of a gasoline engine with a spark ignition of the incandescent coil in the intake air line, which will receive power from the battery. Such modernization of the system does not require major design changes and significant financial investments Unresolved issues remain to assess the effectiveness of the process of heating the air entering the combustion chamber of the engine to create a working mixture. It should be noted that the optimal heating of the engines is most appropriate to carry out (ie heating the coolant and oil in the engine lubrication system) not to the temperature of the operating thermal mode, but to the temperature that ensures its reliable start. Results. The scheme of connection of a heater of intake air in an onboard electric network of the car is presented. The results of the heat balance of the studied gasoline engine (using cold and heated air flow) during its heating are obtained. The optimum temperature of the warmed-up engine at which further economical operation of the car is possible is established. Originality. This spiral heater was first used to heat the intake air charge during the start-up and warm-up of a gasoline engine. Practical value. The developed heating equipment can be used for both gasoline and diesel internal combustion engines. It should be switched on only during engine start-up and warm-up.

ACCRUE—An Integral Index for Measuring Experimental Relevance in Support of Neutronic Model Validation

A key challenge for the introduction of any design changes, e.g., advanced fuel concepts, first-of-a-kind nuclear reactor designs, etc., is the cost of the associated experiments, which are required by law to validate the use of computer models for the various stages, starting from conceptual design, to deployment, licensing, operation, and safety. To achieve that, a criterion is needed to decide on whether a given experiment, past or planned, is relevant to the application of interest. This allows the analyst to select the best experiments for the given application leading to the highest measures of confidence for the computer model predictions. The state-of-the-art methods rely on the concept of similarity or representativity, which is a linear Gaussian-based inner-product metric measuring the angle—as weighted by a prior model parameters covariance matrix—between two gradients, one representing the application and the other a single validation experiment. This manuscript emphasizes the concept of experimental relevance which extends the basic similarity index to account for the value accrued from past experiments and the associated experimental uncertainties, both currently missing from the extant similarity methods. Accounting for multiple experiments is key to the overall experimental cost reduction by prescreening for redundant information from multiple equally-relevant experiments as measured by the basic similarity index. Accounting for experimental uncertainties is also important as it allows one to select between two different experimental setups, thus providing for a quantitative basis for sensor selection and optimization. The proposed metric is denoted by ACCRUE, short for Accumulative Correlation Coefficient for Relevance of Uncertainties in Experimental validation. Using a number of criticality experiments for highly enriched fast metal systems and low enriched thermal compound systems with accident tolerant fuel concept, the manuscript will compare the performance of the ACCRUE and basic similarity indices for prioritizing the relevance of a group of experiments to the given application.

BEPU Analysis in LBLOCA Safety Review Calculation

Deterministic safety analysis (DSA) is essential for nuclear power plant licensing. The conservative method followed CFR50 Appendix K, which will lead to a large margin. As one of the DSA methodologies, best estimate plus uncertainty (BEPU) generates more realistic results that can be used in the license application of nuclear power plants (NPPs). However, uncertainty evaluation of parameters is needed in BEPU. In this article, the safety regulatory focuses on the large break loss of coolant accident (LBLOCA) of an advanced PWR. The BEPU analysis is mainly performed by TRACE V5.0 patch 4 code, and the uncertainty analysis is conducted based on DAKOTA code. For correlation coefficients analysis, the sample size is enlarged reasonably. According to the results, this NPP meets the acceptance criteria effectively in LBLOCA with enough margin. By statistic assessment, the set of PCTs calculated has typical normal distribution characters. Based on BEPU, the uncertainties of parameters are studied. Additionally, the influence of sample size on the correlation of parameters is considered too. It could be seen that more samples could permit a more accurate estimation for Spearman partial correlation coefficient (abbreviated as SPCC). The conclusions of this article can provide technical support for the subsequent review of the safety analysis report and the design changes of NPPs.

America’s Automobile: Affection or Obsession, Myth or Reality?

Mythology plays an important part of the role of the American automobile, less so in terms of its primary function that is transportation, more so in terms of an ancillary purpose: its metaphorical significance to both owner or operator and the onlooking public. Across much of the 20th century and continuing now into the third decade of the 21st century, the American automobile has undergone many design changes that have buttressed its metaphorical significance: become streamlined, gained then lost then partially regained size together with a colorful exterior, and in the 21st century become focused on an array of interior gadgets, some cast into hibernation because of an electronic chip scarcity resulting from trade wars and the Covid-19 pandemic. Many Americans seem to have almost become besotted by automobiles, including their own and those driven by others, because in some respects the American automobile has come to define its driver. Automobiles in the United States that are visually appealing symbolize affluence, material success, preoccupation with speed, including the rapid pace of social change, as well as, at least arguably, a lesser regard for protecting the environment. On balance, in the mindset of many Americans, the automobile is larger than life, “a mode of signification, a form” in contrast to a mere machine. Change in automotive design has been heralded as the talisman of a new generation of drivers. However, what is cause and what is effect? American automobiles conflate myth and reality; that which is together with that which might be sometime temporal frustrations with the American Dream.

Generic Upscaling Methodology of a Floating Offshore Wind Turbine

This study presents a generic method to upscale a semi-submersible substructure and tower-nacelle-blade for a floating offshore wind turbine from 5 MW to 15 MW and beyond. The effects of upscaling the column radius and/or distance of the floating base are investigated, and a comparison is made with a 15 MW reference design. It is found that scaling column radius increases the mass of the platform and the heave natural period, while scaling column distance raises the center of gravity and metacentric height of the floating system and slightly decreases the heave natural period. The 15 MW reference design addresses these issues through design changes that increase the ballast mass to lower the center of gravity, and increase the added mass to raise the heave natural period. Finally, a method for estimating the scaling of platform parameters with different assumptions is proposed.

Application of Anti-Stigma Design Heuristics for Usability Inspection

User interface evaluation has become important in developing usable health care technologies. Although usability engineering methods have been applied in the design and evaluation of health care software, available heuristics focus on task-work aspects and do not address stigma associated with many health conditions. We used a previous set of heuristics and propose a new set of anti-stigma heuristics to evaluate stigmatization in health care websites. The extended set of heuristics were concurrently applied in a heuristic evaluation and a cognitive walkthrough to evaluate an endometriosis and sexual pain website. The walkthrough involved 5 tasks that required 21 actions to execute. Twenty-six usability problems were identified and recommendations for re-design were made to the design team before end-user testing. The anti-stigma heuristics received worse ratings than the traditional heuristics, resulting in several design changes that might otherwise have been missed. Thus, the new anti-stigma heuristics were a valuable contribution.

THE USE OF A FUZZY LOGIC SET-BASED DESIGN TOOL TO EVALUATE VARYING COMPLEXITIES OF LATE-STAGE DESIGN CHANGES

Advanced design methods, such as set-based design (SBD), can provide a structured approach to evaluating the design space in order to make accurate and informed decisions towards reaching a globally optimal design. The set-based communications required to appropriately implement SBD are counter-intuitive to the point-based communications of a typical design process. The use of a hybrid agent fuzzy logic design tool can help to facilitate the SBD process by ensuring the use of set-based communication of design variables. The design tool uses automation of certain aspects such as data collection and analysis while still allowing for input from human designers. One important advantage of using SBD is the ability to delay decisions until later in the design process when more information is known. This paper focuses on the robustness of the SBD process and its ability to handle late-stage design changes of varying complexity. Multiple SBD experiments instituting design changes of varying magnitude late in the design process were conducted using a hybrid agent fuzzy logic SBD tool. A simplified planing craft design was utilized for the experiments. Conclusions regarding the robustness of the SBD process under late-stage design changes were determined and outlined using information gathered by the SBD tool.