Design Point Research Articles

Chemometrics‐Empowered Optimization of a Reliable Reversed Phase–High Performance Liquid Chromatography Method for the Simultaneous Estimation of Erythromycin and Adapalene in Pharmaceutical Nanoformulation

ABSTRACTAn innovative, simple, economical, and sensitive reversed phase–high performance liquid chromatography (RP–HPLC) chromatographic method for simultaneous analysis of erythromycin (ERY) and adapalene (ADP) in bulk and pharmaceutical nanoformulation was developed by analytical quality‐by‐design (AQbD) avenue. According to published research, there is no strategy that integrates RP–HPLC with AQbD for estimating ERY and ADP. The analysis was carried out with Box–Behnken design, which reduced trial runs and design points. Acetonitrile: orthophosphoric acid (OPA) (0.1% triethanolamine) in pH 6.2 water was used as the mobile phase. The ratio was set to 35:65 (v/v) at 0.8 mL/min flow rate to detect the analytes at 231 nm. As per the guidelines in International Conference on Harmonization Q1A (R2), the developed approach was validated. ERY and ADP regression coefficients (r2) were found to be 0.9998 and 0.9999, respectively, over 5–25 µg/mL range. Validation parameters comprising linearity, sensitivity, system suitability, precision, robustness, and accuracy were performed. To assess stability, the drugs were subjected to stress conditions (hydrolytic, oxidative, thermal, and photolytic), and drugs were most vulnerable to degrade in alkaline and oxidative conditions. A new technique successfully analyzed novel drug carriers loaded with ERY and ADP.

An Aero Engine Disk Sizing and Weight Estimation Approach with Improved Temperature Profiles

Abstract During the predesign phase of an aero engine, interdisciplinary parametric studies are crucial for identifying an optimum engine. As innovative engine concepts emerge, it is essential to study trends aiming to minimize climate impact and one of its key contributors, fuel burn. The comparatively heavy disks, subjected to high thermal and mechanical loads, are central to this analysis due to their high impact on the overall module mass. This paper proposes an approach to achieve a first lightweight mechanical design of disks in the predesign phase. Based on a performance and aerodynamic baseline, the design space and physical boundary conditions are set. Firstly, an initial mass optimized disk is derived using simplified temperature profiles and stress calculations under the Mechanical Design Point conditions. Subsequently, all the module disks are considered and an estimation for each bore temperature is achieved through a novel loop over the entire module and all available operating points. By evaluating the temperature and stress profiles across various operating conditions, the lowcyclefatigue life of each disk can be studied. As part of a highly modular engine predesign framework, this method allows for zooming capabilities of single disk calculations by prescribing individual boundary conditions. The proposed approach already yields an initial assessment of the rotors within a short runtime, facilitating simple iterations with the succeeding design phases due to method and tool commonalities. While the primary focus of the current work is on compressor design, the principles presented are adaptable and expandable to turbine disk applications as well.

Replication in random translation designs

Replication is a commonly recommended feature of experimental designs. However, its impact in model-robust design is relatively under-explored; indeed, replication is impossible within the current formulation of random translation designs, which were introduced recently for model-robust prediction. Here we extend the framework of random translation designs to allow replication, and quantify the resulting performance impact. The extension permits a simplification of our earlier heuristic for constructing random translation strategies from a traditional V-optimal design. Namely, in the previous formulation any replicates of the V-optimal design first had to be split up before a random translation can be applied to the design points. With the new framework we can instead preserve the replicates instead if we so wish. Surprisingly, we find that in low-dimensional problems it is often substantially more efficient to continue to split replicates, while in high-dimensional problems it can be substantially better to retain replicates.

Continuous-Time Reinforcement Learning Control: A Review of Theoretical Results, Insights on Performance, and Needs for New Designs.

This exposition discusses continuous-time reinforcement learning (CT-RL) for the control of affine nonlinear systems. We review four seminal methods that are the centerpieces of the most recent results on CT-RL control. We survey the theoretical results of the four methods, highlighting their fundamental importance and successes by including discussions on problem formulation, key assumptions, algorithm procedures, and theoretical guarantees. Subsequently, we evaluate the performance of the control designs to provide analyses and insights on the feasibility of these design methods for applications from a control designer's point of view. Through systematic evaluations, we point out when theory diverges from practical controller synthesis. We, furthermore, introduce a new quantitative analytical framework to diagnose the observed discrepancies. Based on the analyses and the insights gained through quantitative evaluations, we point out potential future research directions to unleash the potential of CT-RL control algorithms in addressing the identified challenges.

Simulations of design and high load operation of a model Francis turbine using bridged approach to turbulence modelling

Abstract Off-design operation of hydraulic turbines is contemporarily frequented for balance of variable energy intermittence in the electric grid. Being operationally highly flexible, these turbines allow a quick transition to off-design operation from the design point. However, such operational flexibility, and therefore the grid balancing capability is impeded by generation of flow instabilities like vortex breakdown during off-design operation. Vortex breakdown causes losses in efficiency and pressure recovery, pressure fluctuations and possibly mechanical vibrations in event of resonance between system natural and flow field fluctuation frequencies. While substantial experimental and numerical effort has already been made to study draft tube vortex breakdown, an accurate numerical flow characterization of the phenomenon is still a challenge. To this end, operation of a high head model Francis turbine under design and high load regimes using a bridged turbulence modelling approach is simulated. The approach allows a seamless transition between direct numerical simulation and Reynolds averaged Navier-Stokes equations. The highest attainable accuracy is limited by the mesh size. As such a satisfactory compromise between desired accuracy and invested computational effort is attained. The flow in the draft tube is free of anomalies under design specified operation. However, at high load an axial flow stagnation occurs centrally, and the flow is separated about the stagnated zone. The core of the vortex is enlarged with flow recirculation within it. Shear layers between the central stagnant zone and surrounding outflow kink and roll up transforming it into a spiral structure. In this work, a basic yet accurate numerical flow characterization of the aforementioned flow situations is achieved.

Sparse Flow Sensor Placement Optimization for Flight-by-Feel Control of 2D Airfoils

This research introduces the Sparse Sensor Placement Optimization for Prediction algorithm and explores its use in bioinspired flight-by-feel control system design. Flying animals have velocity-sensing structures on their wings and are capable of highly agile flight in unsteady conditions, a proof-of-concept that artificial flight-by-feel control systems may be effective. Constrained by size, weight, and power, a flight-by-feel sensory system should have the fewest optimally placed sensors which capture enough information to predict the flight state. Flow datasets, such as from computational fluid dynamics, are discrete, often highly discontinuous, and ill-suited for conventional sensor placement optimization techniques. The data-driven Sparse Sensor Placement Optimization for Prediction approach reduces high-dimensional flow data to a low-dimensional sparse approximation containing nearly all of the original information, thereby identifying a near-optimal placement for any number of sensors. For two or more airflow velocity magnitude sensors, this algorithm finds a placement solution (design point) which predicts angle of attack of airfoils to within 0.10° and ranks within the top 1% of all possible design points validated by combinatorial search. The scalability and adaptability of this algorithm is demonstrated on several 2D model variations in clean and noisy data, and model sensitivities are evaluated and compared against conventional optimization techniques. Applications for this sensor placement algorithm are explored for aircraft design, flight control, and beyond.

The Comparison A-Optimal and I-Optimal Design in Non-Linear Models to Increase Purity Levels Silicon Dioxide

One of the obstacles that arise in optimal design is the non-linear model. The relationship between temperature factors and the temperature increase rates with the purity of silicon dioxide (SiO2) forms a non-linear pattern. Determining the optimal design for a non-linear model is relatively more complex than a linear model because it requires additional information in its information matrix. Therefore, this issue necessitates further research on optimal design in non-linear models. This study uses the polynomial Taylor approach to approximate the non-linear equation through a linear equation using the appropriate optimal design methods, namely A-Optimal and I-Optimal criterion. The point search algorithm used was variable neighborhood search, this algorithm searches for design points by exploring several different neighborhood structures. These two methods were chosen to compare the characteristics and performance of the designs produced, aiming to obtain an optimal design to improve SiO2 purity (non-linear case) using the same algorithm, VNS. The research results showed that the design pattern produced by the A-Optimal design formed three temperature groups, namely the minimum temperature of 800°C - 820°C, the middle temperature of 850°C, 860°C, and the maximum temperature of 900°C, with varying temperature increase rates in the design area. The design pattern produced by the I-Optimal design formed a full quadratic pattern, namely the minimum temperature of 800°C and the maximum temperature of 900°C, with varying temperature increase rates in the design area. The I-Optimal design demonstrated the best performance (most optimal) in the aspect of prediction variance compared to the A-Optimal design across all alternative points in this study to improve SiO2 purity.

The Role and Functions of City Parks in the Adaptation Process of Refugees to the City: The Case of Ulubey Şehit Ömer Karaosmanoğlu Park

Today, migration mobility is experienced intensely all over the world. As refugees seek asylum in their countries of origin, the process of integration begins spontaneously, and urban parks, which are the most important part of the public space and provide the unity of the city dwellers, play an active role in this process. "How does the use of urban parks change with the unpredictable number of refugees all over the world and especially in Turkey and how does this situation find expression in Ankara?" is the starting point of the study, while "the fact that refugees are under difficult socio-cultural and economic conditions has led to the use of urban parks and negatively affected the use of parks by local people" is the hypothesis of the study. Within the scope of the study, Ulubey Şehit Ömer Karaosmanoğlu Park, located in Altındağ district of Ankara, which is one of the countries hosting the highest number of refugees in the world and has the highest Syrian population in Ankara, was selected as the sample area and the park usage tendencies of both refugees and local people, how they feel about using the park together and whether the park contributes to the adaptation process were examined through a face-to-face survey. According to the survey data; it has been determined that there is not a full harmonization between the refugees using Ulubey Şehit Ömer Karaosmanoğlu Park and the local people and refugee women have more difficulties in harmonization than refugee men. With this study, solution suggestions are presented to local governments at the point of planning and design of urban parks in countries hosting refugees.

Modified Slope Rotatability for Balanced Ternary Designs of Second Order Response Surfaces

Objective: To evaluate the best optimal solutions of modified Second Order Slope Rotatable Designs (SOSRD) using Balanced Ternary Designs (BTD) and to compare with different methods of Modified SOSRD for 3≤v≤8. Methods: To estimate the parameters of the response surface design of second order the principle of least squares was applied for design of experiments, we also evaluated modified slope rotatable value and variance of estimated responses. Findings: The outcome of this research reveals the influence of various design parameters on key aspects such as the variance of the estimated response, slope rotatable value, axial points, central points and also total number of design points of modified SOSRD framework. Novelty: The variance of the estimated responses in the new method of Modified SOSRD using BTD provides the best optimal solutions with minimum variances while compared to different methods of Modified SOSRD. Keywords: Response ­ Surface Experimental Designs, Second Order Rotatable Designs, Second ­ Order Slope ­ Rotatability, Second ­ Order Modified Slope ­ Rotatability, Balanced Ternary Designs

Key Points of Design and Risk Analysis in Production for Biodegradable Heart Occluder

Biodegradable heart occluder uses a biodegradable medical polymer material to replace or completely replace the metal material. After completing the repair function of the heart defect, the device is gradually degraded and safely absorbed by the human tissue. So it may minimize the risk of long-term complications that traditional metal heart occluder causing in the body after implantation. Based on the quality management concept of the entire lifecycle of medical device, this article briefly introduces design and development, as well as the product realization of biodegradable heart occluder. It analyzes the main risk points in design and production, and corresponding suggestions have been put forward. These suggestions are combined with the medical device good manufacturing practice and the appendix of implantable medical equipment to provide a reference for regulators and industry professionals.

Enhancing transonic compressor rotor efficiency by flow analysis-driven blade section modification

Abstract Transonic axial compressors are widely used in aero-engines and gas turbines, and their efficiency has a significant influence on the equipment energy utilization rate and fuel cost. In this research, blade section modification based on flow analysis is carried out on the Rotor 67 for improving efficiency. First, the numerical calculation method used is verified with experimental data to ensure the accuracy of the simulation. Then, according to the analysis of simulated flow field and shock structure, the blade section shapes are altered to optimize the blade passage wide distribution for the sections from hub to mid-span. In addition, the blade surface angle is altered to reduce the supersonic flow expansion angle for decreasing shock strength. With these optimizations, the efficiency of modified transonic rotor increases by 0.9 percentage at the design point and 1.0 percentage at near stall point (N = 1.0), respectively. Slightly higher efficiency at off-design speeds (N = 0.9 and 0.8) are also obtained, with maintaining the stall margin.

Second type second order slope rotatable designs utilizing symmetrical unequal block arrangements with two unequal block sizes

Kim and Ko developed second order slope rotatable designs (SOSRD) of second type utilizing central composite designs (CCD), in which two numbers are used to represent the positions of star points. In this paper, we suggest second type SOSRD utilizing symmetrical unequal block arrangements (SUBA) with two unequal block sizes. In some cases, the suggested method may develop designs containing fewer design points than second type SOSRD obtained utilizing CCD, pairwise balanced designs (PBD) and balanced incomplete block designs (BIBD). The first order partial derivative's for estimated second order response variance for factors 6≤v≤15 is also obtained.

Dual-Loop μ-Synthesis Direct Thrust Control for Turbofan Engines

As the power unit of an aircraft, the engine’s primary task is to provide the demanded thrust, making research on direct thrust control crucial. However, being a complicated multivariable system, effective multivariable direct thrust control methods are currently lacking. The main content of this paper is threefold. First, it presents a dual-loop multivariable μ-synthesis direct thrust control scheme for mixed-exhaust low-bypass turbofan engines, which is a typical rotationally symmetric machine. The scheme adjusts fuel flow for thrust control and nozzle area to control the turbine pressure ratio, ensuring thrust tracking while maintaining the engine’s key parameters within safe limits. Second, a fast, accurate thrust estimation algorithm based on aerodynamic thermodynamics and component characteristics is introduced. At last, considering the model uncertainties between off-design and design points, a weight function frequency shaping μ-synthesis control design method is proposed to address internal loop coupling and external disturbance suppression. Nonlinear simulations within the flight envelope show that μ-synthesis direct thrust control achieves robust servo tracking and disturbance rejection, with a maximum steady-state thrust error of no more than 0.1%, and the key parameters are not over their safety boundaries.

Energy and Environmental Analyses of a Solar–Gas Turbine Combined Cycle with Inlet Air Cooling

Sensitivity to ambient air temperatures, consuming a large amount of fuel, and wasting a significant amount of heat dumped into the ambient atmosphere are three major challenges facing gas turbine power plants. This study was conducted to simultaneously solve all three aforementioned GT problems using solar energy and introducing a new configuration that consists of solar preheating and inlet-air-cooling systems. In this study, air was preheated at a combustion chamber inlet using parabolic trough collectors. Then, inlet air to the compressor was cooled by these collectors by operating an absorption cooling cycle. At the design point conditions, this novel proposed integration resulted in a 6.87% relative increase in generated power and a 10.53% relative decrement in fuel consumption, achieving a 19.45% relative increment in the plant’s thermal efficiency. This was accompanied by a reduction of 0.026 kg/s, 4.2 kg/s, and 0.278 kg/s in CO2, CO, and NOx emissions, respectively. Finally, spider diagrams were employed to assess the impact of the operating parameters on the overall system’s performance and its associated environmental implications.

Enhancing payload capacity to low earth orbit via a relay solution trajectory with laser-powered vehicles

ABSTRACT Low Earth Orbit (LEO) stands as the primary access point for deep space exploration endeavors, encompassing a variety of space missions such as communication satellites, Earth observation platforms, and scientific research missions. In light of the expanding scope of human activities in space, the cost associated with accessing LEO has emerged as a critical focal point for spacecraft designers. Within the spectrum of proposed solutions, laser-powered vehicle has emerged as a viable avenue toward achieving cost-effective launch options. In order to significantly augment the payload capacity of laser-powered launch vehicles destined for LEO, this study introduced a novel Relay Solution Trajectory Flight Scheme. Central to this scheme was the implementation of a relay mirror system affixed to a satellite, which served to stabilize the incident angle of the laser beam directed toward the laser-powered vehicle, thereby ensuring continuous alignment between the laser beam and the vehicle’s axis throughout the duration of the flight. Following the development of comprehensive structural, propulsive, aerodynamic, and trajectory models tailored for the laser-powered vehicle, an optimization of its flight trajectory was conducted, comparing this innovative strategy with two conventional flight strategies. The outcomes of this analysis showcased a notable enhancement of 269.29% in payload capacity compared to conventional strategies that lacked a relay satellite system, within a designated 400 km LEO flight scenario. This endeavor underscored the transformative potential of advanced relay systems in reshaping payload delivery mechanisms and elevating mission feasibility levels, notwithstanding the intricate coordination challenges posed by intricate satellite systems.

A single-loop reliability sensitivity analysis strategy for time-dependent rare events with both random variables and stochastic processes

To deal with the time-dependent reliability sensitivity (TDRS) analysis of rare events with both random variables and stochastic processes, a single-loop sampling procedure combined with the cross entropy-based importance sampling strategy (CEIS), namely SCEIS, is derived to lighten the computational burden without loss of precision. Firstly, the TDRS indices are derived to make them implementable by a single-loop importance sampling (IS) procedure. Then, the quasi-optimal IS density is obtained through the extension of the cross-entropy method, which is an adaptive procedure that overcomes the challenges of determining the position and number of design points in traditional IS. Furthermore, the SCEIS can be easily implemented to estimate the TDRS indices for problems with small failure probability. Three examples involving numerical and engineering problems are analyzed to demonstrate the performance of the proposed method. The results obtained from comparing with other existing methods reveal that the proposed method provides satisfactory TDRS analysis for rare events while significantly reducing computational costs.

Development of simple stability indicating RP-HPLC method to estimate ferulic acid in niosomes and marketed products using quality by design approach

Ferulic acid found in Feru-guard which is obtained from rice bran. This compound occurs in a wide range of plant sources including pineapple, various grasses, rice, leaves, beans, coffee beans, oats, grains, vegetables, flowers, fruits, peanuts and nuts. Particularly, it received a lot of attention due to its potential therapeutic uses in different pathologies, including metabolic, viral infections, cancer, cardiovascular, skin disorders, diabetes, hepatotoxicity and neurodegeneration. The article describes the methodical development of a simple, fast, highly sensitive, durable, efficient and economically viable reversed-phase high-performance liquid chromatography (RP-HPLC) technology for measuring ferulic acid. The analysis was Performed using the Central composite design (CCD), which offers the advantage of employing a reduced number of design points and experimental runs. Employing the response surface methodology via central composite design (CCD), the study thoroughly assessed the influence of these factors. The proposed analytical method underwent comprehensive validation, ensuring its reliability as per the guidelines outlined in ICH Q2A and ICH Q2B.The preferred method employed a mobile phase consisting of Methanol and OPA buffer (50:50 % v/v, pH maintain to 4.2 with 0.1 % orthophosphoric acid), operating at a flow rate of 1 mL min⁻1,with a Chemsil ODS column, the wavelength of detection was set at 320 nm. According to the novel analytical method, Ferulic Acid exhibited a peak retention time of approximately 6.13 min. The method demonstrated linearity range of 0.5–16 μg/ml. The developed approach proved to be robust, precise and accurate, with a recovery rate of 98 %. It achieved % relative standard deviation (RSD) of below 2 %,The current stable RP-HPLC method was effectively employed for the characterization of niosomes loaded with Ferulic Acid. Furthermore, degradation studies were conducted under various conditions to elucidate the degradation pathways and resultant products.

Optimizing the Performance of Window Frames: A Comprehensive Review of Materials in China

As the construction industry places increasing emphasis on environmental conservation and sustainability, this trend has spurred profound research into the optimization of door and window performance. One of the critical components of windows is their frames. Over the past several decades, the design of window frames has undergone significant innovations, ranging from introducing new materials to novel design concepts. The performance of window frames is typically influenced by materials, structural design, and the surrounding environment. Consequently, this paper analyzes the common window frame materials in Chinese civil buildings through investigation. It explores commonly used types of window frames available in the market, focusing on their materials and structural designs. It analyzes issues observed during their usage, integrates findings from existing research, and discusses the performance of window frame materials. Additionally, it explores improvement strategies to meet the evolving demands of contemporary and future architectural doors and windows, providing valuable reference points for designers. Finally, approaching the discussion from a sustainable development perspective, the paper evaluates the environmental impact of wood, aluminum alloy, polymer, and composite window frame materials. It emphasizes that wood- and aluminum-clad wood windows represent sustainable options with versatile applications in diverse scenarios.

Research on Key Points of Design of Standard Plants in Modern Industrial Parks Under the Background of Promoting the Development of New Quality Productive Forces

With the progress of science and technology and the acceleration of industrialization, the modern industrial park is an important carrier of industrial development. The importance of its standard plant design has become increasingly prominent. With the development of new quality productive forces as the background, this research deeply discusses the key points of standard plant design in modern industrial parks. This paper uses literature review and case analysis to systematically analyze the important role of standard plant design in developing new quality productive forces in modern industrial parks and puts forward suggestions for optimizing design. It is found that the rationality, intelligence, and environmental protection of plant design are the key factors affecting the development of new quality productive forces. The paper summarizes the core points of modern industrial park standard plant design to provide a reference for the future development of related industries.

Investigations on conical lean turbulent premixed hydrogenated natural gas flames

Hydrogen's ability to enhance carbon neutrality in combustion processes puts forward the use of hydrogenated fuels, both in the form of fuel and an energy carrier as a potential decarbonization solution. However, because of the nature of hydrogen, blending it with hydrocarbons causes crucial structural changes in the flame structure, including higher flame propagation velocities and higher flame temperatures, decreased instantaneous flame thickness, and increased risks of flame flashback and an increasing potential of NOx emissions due to higher flame temperatures. These attributes encourage a thorough examination of hydrogenated blends of hydrocarbon fuels. Using lean premixed fuels is another technique to achieve efficient and cleaner combustion. However, due to the problem of flame instability in lean premixed combustion, forecasting the design points in terms of flame attributes is critical for better combustor designs.In this study, conical (Bunsen type) lean premixed turbulent flames of hydrogenated natural gas-air mixtures are experimentally studied. Through chemiluminescence measurements of the OH* and CH* radicals and laser-induced Mie scattering, lean natural gas-air premixed flames are examined with subsequently increasing hydrogen addition rates up to 20% by volume and keeping the premixture velocity constant. The obtained data is utilized for exploring the dynamics of the turbulent flame front. The main turbulent premixed flame parameters we identified relate to the instantaneous and average topology of the flame such as the turbulent flame brush thickness and flame height. We also inferred global combustion parameters like the turbulent flame propagation speed from the experimental findings.