Module Layout Research Articles

Polarization-insensitive optical coherence tomography using pseudo-depolarized reference light for mitigating birefringence-related image artifacts.

Optical coherence tomography (OCT) images are prone to image artifacts due to the birefringence of the sample or the optical system when a polarized light source is used for imaging. These artifacts can lead to degraded image quality and diagnostic information. We aim to mitigate these birefringence-related artifacts in OCT images by adding a depolarizer module in the reference arm of the interferometer. We investigated different configurations of liquid crystal patterned retarders as pseudo-depolarizers in the reference arm of OCT setups. We identified the most effective depolarization module layout for polarization artifact suppression for a spectral-domain OCT system based on a Michelson and a Mach-Zehnder interferometer. The performance of our approach was demonstrated in an achromatic quarter-wave plate allowing the selection of a variety of sample polarization states. A substantial improvement of the OCT signal magnitude was observed after placing the optimal depolarizer configuration, reducing the cross-polarization artifact from 5.7 to 1.8dB and from 8.0 to 1.0dB below the co-polarized signal for the fiber-based Michelson and Mach-Zehnder setup, respectively. An imaging experiment in the birefringent scleral tissue of a post-mortem alpine marmot eye and a mouse tail specimen further showcased a significant improvement in the detected signal intensity and an enhanced OCT image quality followed by a drastic elimination of the birefringence-related artifacts. Our study presents a simple yet cost-effective technique to mitigate birefringence-related artifacts in OCT imaging. This method can be readily implemented in existing OCT technology and improve the effectiveness of various OCT imaging applications in biomedicine.

Heat pipe-enhanced two-stage thermoelectric harvester based on phase change material

The thermoelectric generator (TEG) technology is important for improving energy efficiency. However, the TEG limited by poor thermoelectric material properties and thermal transfer strategies faces challenges in achieving excellent heat harvesting capacity, especially for large-temperature gradients. Herein, we reported a heat pipe-enhanced two-stage thermoelectric generator (HTTEG) enabled by bismuth alloy-based PCM for effective space waste thermal harvesting. We comprehensively explored the effects of different thermal-enhanced strategies on HTTEG performance. Compared with copper plate and horizontal layout, the effective thermal conductivity obtained by vertical-planar heat pipe is 1.1 × 104 W/mK enhanced by 79.2 and 33.0 times, which has outstanding advantages in achieving considerable temperature difference and excellent thermoelectric harvesting capacity of the HTTEG. We also systematically discussed the thermoelectric properties of heat pipe-enhanced one-stage TEG (HOTEG) and HTTEG by simulation and LED test bench. The results show that the bismuth alloy-based PCM with considerable latent thermal capacity and remarkable heat transfer characteristics can suppress temperature fluctuations and expand thermoelectric harvest interval, achieving excellent power output capacity. Compared with the HOTEG, the thermoelectric power achieved by HTTEG is 4.45 W enhanced by 581.8 %, because optimizing the spatial layout of stage-two thermoelectric modules to the high-temperature gradient interval achieves remarkable heat harvesting efficiency.

Analytical Overview of the Methods of Controlling the Parameters of Vibratory Compaction of the Concrete Mixes

Introduction. A historical (retrospective) overview of the evolution and application of the methods of concrete mixture compaction by vibration, as well as an overview of the breakthrough scientific+ advancements in the studied field have been presented. The use of the dry concrete mixes that reduce cement consumption, accelerate the strength gain of concrete, reduce the shrinkage strain and heat emission and increase the strength and durability of products has been proposed. The theoretical and practical issues of vibratory compaction of the concrete mixes, the research on the effect reached by the various vibration modes of the vibrating tables, the issues of choosing an efficient mode of vibration impact during compacting the concrete mixes and optimisation of their parameters have been studied. The vibrating table design, the installation layout of the vibrator’s eccentric weights to obtain a given value of the exciting force and the layout of a vibration module with the directed vibrations have been studied in detail. The criteria of duration of the concrete mixture compaction have been defined, changes of the impact parameters during compacting the concrete mixes have been characterised and technical specifications of the vibrating tables have been defined. In the article considerable attention has been paid to the main parameters of the vibrocompacting machines: frequency, amplitude and acceleration of the working member. Most often, the parameter of intensity is used to assess the efficiency of the vibration impact received by the mixture during the compaction process.Materials and Methods. A mixture that turns into concrete after compaction, setting and hardening was selected for the research. The various methods and parameters of concrete mixture compaction to obtain the high-quality concrete were studied. The impact of the various vibration modes on the process of compaction of concrete mixes was investigated, the criteria for the efficient selection and optimisation of the vibration impact parameters were revealed. The paper presents the criteria for assessing duration of the concrete mixture compaction and describes the changes in the parameters during compaction of the concrete mixes. The technical specifications of the vibrating tables of different types and sizes were also presented. The choice of the vibration compaction mode for the concrete mixture is a complicated task, which includes many parameters.Results. Upon the research, the data on the process of concrete mixture compaction under the impact of vibration forces has been obtained. The process results in the destruction of the structural bonds and weakening the bonds between the particles, which leads to the emergence of a variable stress-strain condition. It has also been found that under such settings, the mineral particles get transferred and a denser packing is formed.Discussion and Conclusion. The resulting denser packing of the concrete mixture particles ensures the undoubted economic advantage due to reduced consumption of a binder without loss of the strength properties of concrete.

A module layout design tool for off-site factory construction: Reactor Auxiliary balance of plant systems case study

There is significant interest in off-site modular factory construction for nuclear power. The IAEA defines Small Modular Reactors as “factory shop built and transported to site” and lists over 30 water cooled, 14 high temperature, 10 fast neutron, 10 molten salt, and 8 micro reactors in development worldwide. Off-site modular construction is a new development and offers more reliability in the construction and nuclear industries. A tool to help designers navigate the plethora of increased options and design challenges that modular design presents has therefore been identified as possibly increasing the efficiency and effectiveness of the design process, especially in the concept design phase. This study found that the method can create a starting point for design engineers to iterate and improve designs, significantly reduce design time in finding improved solutions, and improve performance and reduce costs associated with pipe length and network flows around the plant.

Two-Level Approach for Simultaneous Component Assignment and Layout Optimization with Applications to Spacecraft Optimal Layout

Optimal layout problems consist in positioning a given number of components in order to minimize an objective function while satisfying geometrical or functional constraints. Such kinds of problems appear in the design process of aerospace systems such as satellite or spacecraft design. These problems are NP-hard, highly constrained and dimensional. This paper describes a two-stage algorithm combining a genetic algorithm and a quasi-physical approach based on a virtual-force system in order to solve multi-container optimal layout problems such as satellite modules. In the proposed approach, a genetic algorithm assigns the components to the containers while a quasi-physical algorithm based on a virtual-force system is developed for positioning the components in the assigned containers. The proposed algorithm is experimented and validated on the satellite module layout problem benchmark. Its global performance is compared with previous algorithms from the literature.

Simulation and Design of Three 5G Antennas

In the context of 5G networks, this paper investigates microstrip array antennas and mobile terminal MIMO array antennas. It introduces two innovative designs and, based on these, develops and fabricates a mobile terminal antenna. The first of these designs, a 4 × 4 microstrip array antenna operating in the LTE band 42 (3.4–3.6 GHz), is researched and fabricated and an innovative approach, combining embedded and coaxial feeding methods, is proposed and employed. Measurement results indicate a bandwidth of 373 MHz (3.321–3.694 GHz), achieving a relative bandwidth of 10.7%. The antenna exhibits a high gain of 12.7 dBi, with an undistorted radiation pattern, demonstrating excellent directional characteristics. The second of these designs, a “loop-slot” MIMO antenna designed for 5G mobile devices with metal frames, is investigated. By opening slots in the metal frame and integrating them into the antenna’s feeding structure, the decoupling principle is analyzed from the perspective of characteristic mode theory. This design shares resonant modes between the loop and slot antennas, allowing for the overlapping placement of the two antenna units. Experimental results confirm an isolation level exceeding 21 dB, with significantly reduced dimensions. Finally, an eight-unit MIMO antenna is designed and fabricated for 5G mobile devices with metal frames. Continuous optimization of the “loop-slot” module layout and unit spacing leads to a compact and miniaturized antenna structure. Measurement results show an isolation level exceeding 17 dB, radiation efficiency ranging from 65.8% to 73.7%, and an envelope correlation coefficient (ECC) below 0.03. Finally, an analysis of specific absorption rate (SAR) demonstrates excellent MIMO performance in terms of human body radiation exposure.

Innovative Reverse Current Coupling Layout of SiC Power Module for Parasitic Inductance Reduction

Innovative Reverse Current Coupling Layout of SiC Power Module for Parasitic Inductance Reduction

Catalyzing satellite communication: A 20W Ku-Band RF front-end power amplifier design and deployment.

This paper presents a groundbreaking Ku-band 20W RF front-end power amplifier (PA), designed to address numerous challenges encountered by satellite communication systems, including those pertaining to stability, linearity, cost, and size. The manuscript commences with an exhaustive discussion of system design and operational principles, emphasizing the intricacies of low-noise amplification, and incorporating key considerations such as noise factors, stability analysis, gain, and gain flatness. Subsequently, an in-depth study is conducted on various components of the RF chain, including the pre-amplification module, driver-amplification module, and final-stage amplification module. The holistic design extends to the inclusion of the display and control unit, featuring the power-control module, monitoring module, and overall layout design of the PA. It is meticulously tailored to meet the specific demands of satellite communication. Following this, a thorough exploration of electromagnetic simulation and measurement results ensues, providing validation for the precision and reliability of the proposed design. Finally, the feasibility of that design is substantiated through systematic system design, prototype production, and exhaustive experimental testing. It is noteworthy that, in the space-simulation environmental test, emphasis is placed on the excellent performance of the Star Ku-band PA within the 13.75GHz to 14.5GHz frequency range. Detailed power scan measurements reveal a P1dB of 43dBm, maintaining output power flatness < ± 0.5dBm across the entire frequency and temperature spectrum. Third-order intermodulation scan measurements indicate a third-order intermodulation of ≤ -23dBc. Detailed results of power monitoring demonstrate a range from +18dBm to +54dBm. Scans of spurious suppression and harmonic suppression, meanwhile, show that the PA evinces spurious suppression ≤ -65dBc and harmonic suppression ≤ -60dBc. Rigorous phase-scan measurements exhibit a phase-shift adjustment range of 0° to 360°, with a step of 5.625°, and a phase-shift accuracy of 0.5dB. Detailed data from gain-scan measurements show a gain-adjustment range of 0dB to 30dB, with a gain flatness of ± 0.5dB. Attenuation error is ≤ 1%. These test parameters perfectly align with the practical application requirements of the technical specifications. When compared to existing Ku-band PAs, our design reflects a deeper consideration of specific requirements in satellite communication, ensuring its outstanding performance and uniqueness. This PA features good stability, high linearity, low cost, and compact modularity, ensuring continuous and stable power output. These features position the proposed system as a leader within the market. Successful orbital deployment not only validates its operational stability; it also makes a significant contribution to the advancement of China's satellite PA technology, generating positive socio-economic benefits.

Experimental study of optimization of thermoelectric modules’ number and layout for waste heat recovery

A thermoelectric system should be designed in such a way that it harvests as large water heat as possible while using the least modules. To seek an optimal module number, the present study investigates the effect of source temperature, mass flow rate, turbulator, module number and layout on performance of a thermoelectric generator (TEG) system. The experimental results show the optimal module number isn't a fixed value and turbulator has a significant influence on the whole performance of the thermoelectric system. For compact configuration of TEG, using six modules is the best choice without a turbulator, while using eight modules has the best performance with turbulator. The study shows that module layout has a great effect on the thermoelectric system performance. Compared to compact configurations, all separate ones can harvest more power from the hot air except for 32 modules, enhancing by 10–50% whether the turbulator exists or not. In this situation, eight modules are optimal number. The net output power achieves a maximum value of 16.93W and the maximum net efficiency is 3.85% under present experimental parameters. Meanwhile, a new index called power uniformity coefficient is introduced to assess the distribution of output power among TEGs.

Cross-phase automated structural design of modular buildings using a unified matrix method and multi-objective optimization

Traditional structural design of modular buildings involves multi-phase work, which is a labor-intensive process with low efficiency. The tasks in each stage are independent and fragmented. To address such problem, a cross-phase automated structural design of modular buildings is proposed. From the computer-aided design plain drawing, the building elements are extracted to conduct the sematic segmentation of zones using the layer classification method and graph structure. Based on a unified matrix method, the categorized modules are arranged to meet the architectural functions and the structural analysis model is established. Then a multi-objective optimization method is applied to perform the structural design considering the safety demand and economic benefit of the structure. Lastly, the data file is generated to conduct the structure-to-digital model delivery. The proposed method is shown to be effective and fully automated through two practical cases. The proposed framework integrates module layout, parametric modeling, structural optimization and digital model generation as a continues procedure, which also realizes the efficient transfer of different data items including architectural plan, structural model and digital model. It provides a guideline to automated structural design of modular buildings.

Performance Assessment of Cell-Separation Processes for Rear-Contact Solar Cells: Comparison of Indoor and Outdoor Measurements

Half-cell and third-cell modules are the current module technology standard due to their enhanced electrical performance. Also, special module layouts for building or vehicle integrated photovoltaics rely on non-standard cell formats obtained by separation techniques. For either application, interdigitated back-contact (IBC) solar cells are one of the promising cell technologies due to their higher performance and more aesthetic appearance. Thus, a cell separation process, usually employing laser tools, is needed that splits the cells as partial cells are manufactured from full cells. However, this cell cutting also induces additional electrical losses. In this work, we analyze the performance of third cell mini-modules made of IBC cells in comparison to PERC cells as reference. Under standard test conditions (STC), an overall performance gain can only be found for the PERC cells, while current and recombination losses dominate the IBC mini-modules. Outdoor measurements under non-STC conditions reveal reduced performance gains under lower illumination. We show a detailed analysis regarding the performance differences of the IBC and PERC cell technologies at indoor STC and outdoor non-STC test conditions.

Automation process in data collection for representing façades in building models as part of the renovation process

A key barrier in building-facade renovation processes is that, contrary to new designs, an initial building model where the design process is based rarely exists, and the technologies usually employed to create it (e.g., based on point cloud scanning) are costly or require modeling skills. This situation is a clear limitation, especially in early decision stages, where the level of detail required is not very high, and the analysis and studies to consider the renovation plan (e.g., simplified energy simulations and renovation potential, or estimation of the number, types, and dimensions of the prefabricated modules incorporating solar panels) highly depend on such digital models. This paper introduces a process that, based on freely available data such as open GIS sources (local Cadasters, OpenStreetMap…) and façade images, can semi-automatically generate the 3D building model of the existing conditions, and in a second step also suggests the prefabricated facades module layout for building upgrades. Additionally, no onsite visit is needed. When the upgrade is focused on the façade, a big opportunity is identified for generating the building model and a realistic representation of its envelope, only using online data sources as input. The process developed consists of a set of easy-to-use software tools that can be used independently or combined in a workflow, depending on the available data and starting conditions. Time saving is very clear and costs can be reduced.

Matching the Photocurrent of 2‐Terminal Mechanically‐Stacked Perovskite/Organic Tandem Solar Modules by Varying the Cell Width

Photocurrent matching in conventional monolithic tandem solar cells is achieved by choosing semiconductors with complementary absorption spectra and by carefully adjusting the optical properties of the complete top and bottom stacks. However, for thin film photovoltaic technologies at the module level, another design variable significantly alleviates the task of photocurrent matching, namely the cell width, whose modification can be readily realized by the adjustment of the module layout. Herein, this concept is demonstrated at the experimental level for the first time for a 2T‐mechanically stacked perovskite (FAPbBr3)/organic (PM6:Y6:PCBM) tandem mini‐module, an unprecedented approach for these emergent photovoltaic technologies fabricated in an independent manner. An excellent I sc matching is achieved by tuning the cell widths of the perovskite and organic modules to 7.22 mm (PCE PVKT‐mod = 6.69%) and 3.19 mm (PCE OPV‐mod = 12.46%), respectively, leading to a champion efficiency of 14.94% for the tandem module interconnected in series with an aperture area of 20.25 cm2. Rather than demonstrating high efficiencies at the level of small lab cells, this successful experimental proof‐of‐concept at the module level proves to be particularly useful to couple devices with non‐complementary semiconductors, either in series or in parallel electrical connection, hence overcoming the limitations imposed by the monolithic structure.

A framework for evaluating urban solar adoption considering economic and environmental priorities of project owners

In recent years, the utilization of photovoltaic (PV) solar systems in built-up regions have received more attention due to global warming issues and the need to mitigate the dependence on fossil fuels in buildings. In this context, it becomes critical to comprehend the economic and environmental implications of roof-installed PV systems for project owners looking to expand their usage. Thus, there is a need to develop a framework for optimizing rooftop solar PV systems in urban regions considering the economic and environmental aspects with regard to the PV project owners’ priorities, in addition to the energy-saving context, which was addressed in previous studies. Therefore, this study develops a search space optimization method to find the optimum layout of PV modules on roofs of buildings in urban regions, considering solar PV project owners' economic and environmental priorities. Payback time (PBT) and CO2 emission savings are considered for the economic and environmental criteria calculations, respectively. The results show the significance of owners’ economic and environmental priorities toward PV module arrangement on roofs. Instead of having an entire economic priority, having a 25 % environmental priority enhances annual PV system output and CO2 emission savings about 1.5 times with almost the same PBT.

Method for Investigation of the Cooling Process of a Layout of a Lithium Divertor Module (LDM) under High Energy Loads

Method for Investigation of the Cooling Process of a Layout of a Lithium Divertor Module (LDM) under High Energy Loads

Multi-objective Optimization for the Base Lattice Structure of a Small Space Sampling Return Capsule

The space sample-return mission capsule will bear a large landing impact at the moment of landing, so the return capsule structure is required to be the lightest under the premise of ensuring the safety of equipment and sampling samples. In view of the small size, compact layout and high lightweight requirements of the space sample-return mission module, the base lattice structure made of additive materials can achieve better comprehensive performance of landing impact resistance. In this paper, design of experiments (DOE) and surrogate model are used to carry out parameter sensitivity analysis and multi-objective optimization for the base lattice structure of small return capsule landing impact for space sampling. First, the parametric model of the large base lattice of the landing impact dynamics of the return capsule was established. Then, the Latin Hypercube Sampling (LHS) method was used to carry out sensitivity analysis of the lattice structure parameters and identify key factors. Finally, the response surface model was constructed, and the genetic algorithm was used to optimize the lattice structure parameters. The optimal design was obtained. By comparison with the dynamics analysis model, the results of the surrogate model are basically consistent with the dynamic analysis results.

Fast and Accurate Parasitic Extraction in Multichip Power Module Design Automation Considering Eddy-Current Losses

Recent studies in power electronic design automation have introduced various models for parasitic extraction of multichip power module layouts. However, none of these studies consider the eddy current effect in the direct-bonded-copper substrate, accounting for 40-50% error in the extraction result. This work introduces a methodology for eddy-current consideration through numerical simulation and regression modeling. The regression model utilized in the characterization process in this work is fast and memory-efficient compared to the finite element approach. This characterization process can improve the accuracy of any partial element model without sacrificing performance. Combining this characterization process and partial element approach achieves less than 10% extraction error compared to Ansys Q3D while showing a maximum speed-up of 35× and 17× more memory efficiency. This method also significantly reduces the number of elements in the extracted netlist and the complexity of loop evaluation. This method is attractive for use with optimization routines and therefore has been used successfully in a layout optimization tool.

Improving Computation and Memory Efficiency for Real-world Transformer Inference on GPUs

Transformer models have emerged as a leading approach in the field of natural language processing (NLP) and are increasingly being deployed in production environments. Graphic processing units (GPUs) have become a popular choice for the transformer deployment and often rely on the batch processing technique to ensure high hardware performance. Nonetheless, the current practice for transformer inference encounters computational and memory redundancy due to the heavy-tailed distribution of sequence lengths in NLP scenarios, resulting in low practical performance. In this article, we propose a unified solution for improving both computation and memory efficiency of the real-world transformer inference on GPUs. The solution eliminates the redundant computation and memory footprint across a transformer model. At first, a GPU-oriented computation approach is proposed to process the self-attention module in a fine-grained manner, eliminating its redundant computation. Next, the multi-layer perceptron module continues to use the word-accumulation approach to eliminate its redundant computation. Then, to better unify the fine-grained approach and the word-accumulation approach, it organizes the data layout of the self-attention module in block granularity. Since aforementioned approaches make the required memory size largely reduce and constantly fluctuate, we propose the chunk-based approach to enable a better balance between memory footprint and allocation/free efficiency. Our experimental results show that our unified solution achieves a decrease of average latency by 28% on the entire transformer model, 63.8% on the self-attention module, and reduces memory footprint of intermediate results by 7.8×, compared with prevailing frameworks.

Factoring Interacting Stress Mechanisms in Design for Reliability of Extreme Environment Power Modules

As power densification demands are placing electronic packages under greater reliability risk, the consequence of complementary or interacting stresses in producing failure are becoming increasingly significant. As such, it is important that reliability methods and package designs consider how multiple-stress interactions may impact product life. Here, the coordination between a novel accelerated testing method and electronic design automation efforts has demonstrated a successful optimization approach for a wire-bonded 2D module layout combining failure mechanisms of electromigration and mechanical stressing. Utilizing custom, physics-of-failure approaches in accelerated testing, interactions can be observed in failure acceleration, which then can be incorporated into design for reliability (DfR) optimization tools. The PowerSynth 2 platform has been utilized as a design for reliability tool to perform a rapid relative reliability evaluation incorporating multi-stress scenarios. This work demonstrates the value added to reliability evaluation techniques when accounting for interacting failure mechanisms and suggests that next generation power devices consider these effects in lifetime estimation.

Factoring Interacting Stress Mechanisms in Design for Reliability of Extreme Environment Power Modules

As power densification demands are placing electronic packages under greater reliability risk, the consequences of complementary or interacting stresses in producing failure are becoming increasingly significant. As such, it is important that reliability methods and package designs consider how multiplestress interactions may impact product life. Here, the coordination between a novel accelerated testing method and electronic design automation efforts has demonstrated a successful optimization approach for a wire-bonded 2D module layout combining failure mechanisms of electromigration and mechanical stressing. Utilizing custom, physics-of-failure approaches in accelerated testing, interactions can be observed in failure acceleration, which then can be incorporated into design for reliability (DfR) optimization tools. The PowerSynth 2 platform has been utilized as a DfR tool to perform a rapid reliability evaluation incorporating multistress scenarios. This work demonstrates the value added to reliability evaluation techniques when accounting for interacting failure mechanisms and suggests that next-generation power devices consider these effects in lifetime estimation.