Non-uniform Conditions Research Articles

Joint near-isometry and optimal sparse recovery: Nonuniform recovery from multi-sensor measurements

Parallel acquisition systems are widely used in practical applications as they are effective in problems that cannot guarantee the quality of signal reconstruction in case of using a single-sensor system. Many authors have already demonstrated the superiority of the multi-sensor system over the single-sensor system by revealing the nonuniform recovery conditions of the multi-sensor system for optimal recovery in the sense that the number of measurements required per sensor decreases linearly with the total number of sensors, however, the condition on the sensor profile matrices are quite stringent. In this paper, we present nonuniform recovery guarantees based on the so-called joint near-isometry condition, while preserving the advantage of the multi-sensor system and the possibility of stable and robust recovery. The relaxed condition on the sensor profile matrices opens up the possibility of design of considerably wide range of sensor profile. On the other hand, numerical experiments not only show the validity of our theoretical result, but also provide several interesting results such as effectiveness of random sensor profile.

Novel Double Tied Cross Link with Reduced Cross Cables for Maximum Power Extraction under Uniform and Non-Uniform Shading Conditions

Partially shaded panels lead to the creation of troughs in the power generation PV curve, from its optimal potential. Researchers have focally went through for findings in the optimal Photo Voltaic (PV) configuration namely Series (S), Parallel (P), Series–Parallel (SP), Bridge Link (BL), Honey Comb (HC), Total Cross Tie (TCT), Triple Tied Cross Link (TTCL), and Hybrid Configurations. In this paper, a Novel Double Tied Cross Link (DTCL)-based PV panel configuration is proposed. The superiority of the proposed DTCL configuration is that the number of local maximum power points (LMPP) is reduced in certain partial shaded conditions and optimized cost also possible, as the number of cross-links has been reduced, compared to conventional configurations. The maximum power generation superiority of TCT and TTCL has been realized with the proposed novel configuration of Double Tied Cross Link. Using MATLAB/Simulink, different patterns of possible shadings have been created as a replica of real-time partial shadings. Analysis of the proposed DTCL configuration has been implemented along with the conventional configurations in MATLAB simulation. The technical parameters, such as open circuit voltage, short circuit current, maximum voltage, maximum current, fill factor, mismatch losses, and efficiency, are considered for analyzing the proposed DTCL photo voltaic configuration. Besides, this article also presents a novel DTCL PV configuration which reveals cross-cable savings, maximum power attainment, and economically feasible, as usage of cross cables is less, without much compromising on power generation.

Ginzburg Landau Model for Nanofluid Convection in the Presence of Time Periodic Plate Modulation

Here we study thermal modulation effect on nanofluid convection and discuss heat and mass transfer in the layer. The non-uniform time periodic boundary conditions of the system are considered. A weak non-linear stability analysis has been performed and obtained heat and mass transfer coefficients as a function of the system parameters. The Ginzburg Landau model was employed to derive nanofluid convective amplitude at different stages of flow disturbances and modulation. Slow variations of time scale shows that thermal modulation impact on transport phenomenon for the case of out phase modulation (OPM) and (lower boundary modulation) LBM. Also the effect of IPM (in-phase modulation) is observed low effect on Nu and which are similar to un-modulation case. It is also justified that LBM restuls are similar to gravity modulation results. It is found that thermal modulation and concentration Rayleigh numbers are either stabilize or destabilize the system. Further, GL model shows better results on regulation of transport process

A CFD-based framework to assess airborne infection risk in buildings

The COVID-19 pandemic has prompted huge efforts to further the scientific knowledge of indoor ventilation and its relationship to airborne infection risk. Exhaled infectious aerosols are spread and inhaled as a result of room airflow characteristics. Many calculation methods and assertions on risk assume ‘well-mixed’ flow conditions. However, ventilation in buildings is complex and often not showing well-mixed conditions.Ventilation guidance is typically based on the provision of generic minimum ventilation flow rates for a given space, irrespective of the effectiveness in the delivery of the supply air. Furthermore, the airflow might be heavily affected by the season, the HVAC ventilation, or the opening of windows, which would potentially generate draughts and non-uniform conditions. As a result, fresh air concentration would be variable depending upon a susceptible receptor's position in a room and, therefore, associated airborne infection risk.A computational fluid dynamics (CFD) and dynamic thermal modelling (DTM) framework is proposed to assess the influence of internal airflow characteristics on airborne infection risk. A simple metric is proposed, the hourly airborne infection rate (HAI) which can easily help designers to stress-test the ventilation within a building under several conditions. A case study is presented, and the results clearly demonstrate the importance of understanding detailed indoor airflow characteristics and associated concentration patterns in order to provide detailed design guidance, e.g. occupancy, supply air diffusers and furniture layouts, to reduce airborne infection risk.

Damage evolution and full-field 3D strain distribution in passively confined concrete

The damage evolution of concrete under multiple stress states is complicated because the triaxial stress on the heterogeneous concrete affects mesoscale interactions between aggregates and mortar, which further alters the internal cracking of concrete and its load bearing mechanism. Hence, probing the internal cracking evolution of concrete under a complex stress state is the key to better understanding the characteristics and failure mechanism of concrete material. This study conducted a series of X-ray computed tomography (X-CT) tests on fiber-reinforced polymer (FRP) confined concrete with varied in situ axial load levels. Different cross-sections of concrete specimens—circular, square with round corners, and square with sharp corners—were designed to achieve uniform or nonuniform passive confinement conditions. The obtained volumetric images from X-CT clearly exhibited the internal damage evolution of concrete, where crack growth, shear banding, and failure localization were displayed for the concrete under varying triaxial stress states. The development of damage to concrete due to cracking with increasing load was also quantified by image segmentation. In addition, the digital volumetric correlation technique (DVC) was employed to produce the volumetric displacement field and strain distribution in the confined concrete according to the image variation of natural speckles. A three-dimensional internal strain analysis revealed that strain localization was mainly caused by mesoscale concrete heterogeneity and nonuniform confinement. More importantly, this study provides the first database of full-field strain tensors for FRP-confined concrete under different axial load levels. These data are valuable for the development of concrete mechanics, failure criteria of materials, and computational modeling of concrete materials and their structures, especially for concrete under complex stress states.

Salinity distribution pattern and its induced adaptability of tomato roots

Salinity is a major abiotic stress and threat to tomato production. Roots can attenuate salt stress at a specific salinity concentration, especially with non-uniform salinity distribution conditions, and may play a role in enhancing tomato plant adaptability to salt stress. Salt stress will also have a certain impact on root growth, which in turn affects the adaptability of crops to salt stress. Under different salt gradients, if we can find a reasonable distribution strategy, we can increase the tolerance of plants to salt stress. The hydroponics method was used and the roots were split into left and right parts. We established different salinity distribution patterns: a uniform salinity distribution T1 [0, 0], T2 [0.2%, 0.2%], and T3 [0.3%, 0.3%] and a non-uniform salinity distribution T4 [0.1%, 0.3%], T5 [0.1%, 0.5%], T6 [0.2%, 0.4%]. We observed the whole growth stage, and the plant's physiological responses to salt stress were measured. The data indicated that tomato plant roots can attenuate salt stress at a salinity concentration of 0.4%. The non-uniform salinity distribution can restrict root-uptake and uptake efficiency of nutrients (Na+, K+). Fruit yield, flavor and quality were enhanced by the non-uniform salinity distribution of T4 [0.1%, 0.3%]. Increased K+ led to a decreased Na/K ratio, which could reduce the toxicity of salt ions and improve tomato growth. The antioxidant enzyme activities of both roots and leaves of tomato plants were elevated under different salt stress patterns, indicating that the subject plants have the potential to exert adversity adaptations and that the enzyme activities are responsive to the degree of salt stress. Response of tomato fruiting stage growth and development and yield quality to different salt stresses. Growth adaptation of tomato under salt stress conditions. The above issues are discussed to provide a theoretical basis for the salt tolerance mechanism of tomatoes under non-uniform salt stress and the growth status of tomatoes on saline soils.

Analysis on the Effects of Different Receiver Structures and Porous Parameters on the Volumetric Effects and Heat Transfer Performance of Porous Volumetric Solar Receiver

The volumetric solar receiver is an important heat transfer component of the concentrated solar power (CSP) system. Moreover, in order to improve the absorption of concentrated solar radiation, the porous media are widely used in volumetric solar receiver. In recent years, many studies were concerned with the effects of porosity, pore number density and size, Reynolds number, and Darcy number on heat and flow performance in volumetric solar receiver. However, there are few studies on the effects of structure type and geometric parameters on the volumetric effects and the radiation characteristics of a porous volumetric solar receiver with nonuniform heat flux boundary condition. In this contribution, in order to analyze the effects of structures on the volumetric effects and heat transfer performance, we design six types of porous volumetric receiver structures, whereas the volume of different structures keeps consistent. Then, we apply the local non-thermal-equilibrium model and also consider the effect of structure shape on the concentrating solar radiation transport characteristic. Furthermore, we apply the Gaussian distribution model (GDM) to simulate the actual nonuniform heat flux boundary condition. The result shows that drum-type structure (RT-III) has the best heat transfer performance among the six structures; e.g., the outlet average temperature of fluid is up to 851 K when the pore size and porosity of porous media are 2 mm and 0.7, respectively, which is 41 K increased than the scaled cone-type structure. In addition, the pore diameter has less influence on the outlet temperature of fluid, but it has greater influence on the pressure drop. The contribution can provide a reference for this type of solar receiver design and reconstruction.

Non-uniform Illumination Face Recognition Method Based on Improved MobileNetV1

<p>Under ideal illumination conditions, the existing face recognition algorithms can obtain better recognition results. However, under non-uniform illumination conditions, the performance of the face recognition algorithm will be greatly reduced. Moreover, the common facial image classification models have low precision and speed. To address these problems, this paper proposes a non-uniform illumination face recognition method based on the improved MobileNetV1, and constructs a lightweight feature extraction network with MobileNetV1 as the core. To reduce the influence of non-uniform illumination on the face image, we use the MSRCR algorithm to preprocess the face image. A lightweight I-MobileNet model is proposed. We introduce the attention module into the MobileNetV1 model, which enhances the feature extraction capability of the network and improves the recognition performance. At the same time, the model parameters are optimized with Arcface loss function to increase the distance between classes and reduce the distance within classes. Compared with the original MobileNetV1 model, our method shows a significant improvement in recognition accuracy. In comparison with other network models, experiments conducted on the Extended Yale B dataset with the I-MobileNet model demonstrate the effectiveness of the method.</p> <p> </p>

Kinematics of metal flow during rolling of asymmetric thin-walled sections under non-uniform plastic strain conditions

Kinematics of metal flow during rolling of asymmetric thin-walled sections under non-uniform plastic strain conditions

Tracking the histories of individual fuel particles in packed bed combustion

This paper introduces a simple technique for sampling individual fuel particles at various stages in overfeed packed bed combustion. A particle is secured to the end of a thin stainless steel rod, which is then used to track the motion of the particle and to remove it from the bed for sampling at the desired time. The particles so tracked provide a record of changes in mass, volume, density, and individual dimensions as combustion proceeds in the bed. Results of a number of experiments of this sort on the packed bed combustion of parallelepipedal wood particles are presented, which among other things show that particle shrinkage during pyrolysis is generally – but not always – largest along the direction of the wood grain and less in the cross-grain directions. The “tracker rod” technique has the advantage over single particle experiments in a furnace that the particles are exposed to the varying and non-uniform conditions in the actual packed bed of fuel; it is, however, only suited to fixed beds, not fluidized or moving beds.

Hermite radial basis-differential quadrature solution for nonlinear buckling problem of non-uniform continuity boundaries of delaminated cylindrical shells

The progression in developing the composite material led to raise the delamination problem in different structural elements, the continuity paths of the within-thickness delamination problem usually were assumed as uniform to make the governing equations and the solution easier. This paper introduces a treatment of the buckling problem of the delaminated cylindrical shells of composite material with non-uniform delamination boundary using Hermite polynomial as a radial basis in differential quadrature method. The governing differential equations for internally delaminated cylindrical shell subjected to uniformly distributed compression load are obtained considering the variational principle. The non-dimensional analysis is carried out to get the simplest form of the governing differential equation. Both of continuity conditions at non-uniform delamination paths and boundary conditions for hinged and fixed supports are considered, and discretized using the differential quadrature method. The obtained critical buckling load at different thicknesses is verified with both of the exact solution and the solution obtained from generalized differential quadrature that used Lagrange interpolated polynomial as a test function. The results show that the Hermit radial basis differential quadrature is efficient, rapid and simple for treating the non-uniform continuity boundaries.

Intelligent Control Schemes for Maximum Power Extraction from Photovoltaic Arrays under Faults

Investigation of power output from PV arrays under different fault conditions is an essential task to enhance performance of a photovoltaic system under all operating conditions. Significant reduction in power output can occur during various PV faults such as module disconnection, bypass diode failure, bridge fault, and short circuit fault under non-uniform shading conditions. These PV faults may cause several peaks in the characteristics curve of PV arrays, which can lead to failure of the MPPT control strategy. In fact, impact of a fault can differ depending on the type of PV array, and it can make the control of the system more complex. Therefore, consideration of suitable PV arrays with an effective control design is necessary for maximum power output from a PV system. For this purpose, the proposed study presents a comparative study of two intelligent control schemes, i.e., fuzzy logic (FL) and particle swarm optimization (PSO), with a conventional control scheme known as perturb and observe (P&O) for power extraction from a PV system. The comparative analysis is based on the performance of the control strategies under several faults and the types of PV modules, i.e., monocrystalline and thin-film PV arrays. In this study, numerical analysis for complex fault scenarios like multiple faults under partial shading have also been performed. Different from the previous literature, this study will reveal the performance of FL-, PSO-, and P&O-based MPPT strategies to track maximum peak power during multiple severe fault conditions while considering the accuracy and fast-tracking efficiencies of the control techniques. A thorough analysis along with in-depth quantitative data are presented, confirming the superiority of intelligent control techniques under multiple faults and different PV types.

Experimental investigation of the distorted flow field in a new type of direct-connect facility for scramjet studies

A supersonic distorted flow field generated by a new type of direct-connect facility at Mach 2.1 is investigated experimentally via particle image velocimetry (PIV). This facility is designed to accurately reproduce the real flow field in scramjet especially the flow distortion within the isolator, while avoiding the unstart problem in traditional direct-connect facility. The time-averaged velocity fields reveal the principle of flow distortion generated by this facility and show the detailed flow field structures. The mean results suggest that the choose of target parameters distribution will directly affect the performance of this facility. Then, the distorted flow fields in the isolator with a specific non-uniform incoming flow condition are investigated in detail, with the method of proper orthogonal decomposition (POD). The POD analysis of the fluctuating velocity fields finds that there are complex flow field structures within the isolator, including the large-scale vortex structure and the small-scale structure near the wall surface. And these structures in the eigenmodes are associated with the shock wave and the low-velocity region close to the wall surface. Meanwhile, the distorted main flow is also considered to contribute to the flow field instability. Finally, according to the analysis results, the practical guidance of this new type of direct-connect facility is proposed for the subsequent experimental research about scramjet.

Vane–Probe Interactions in Transonic Flows

AbstractIn this article, a numerical investigation of the effect of a miniaturized five-hole probe downstream of a transonic low-pressure turbine vane row is presented. First, a numerical calibration of the probe was performed in uniform flow conditions, as is the case for any traditional calibration, for a wide range of Mach number, yaw angle, and pitch angle conditions. The effect of the probe on the general flow field throughout the turbine vane segments was then evaluated by performing a comparison between a setup with vanes only (no probe) and with vanes and probes. It was found that, as the probe traverses downstream the vane, the probe impact on the vane isentropic Mach number depends on the probe circumferential position. The highest impact was observed when the probe is located at the upper mid-passage (θ = 0.5), consisting of a relatively small reduction of the isentropic Mach number on the vane suction side of just 0.02. To assess the accuracy of the quantities “measured” by the probe, the probe-determined flow field was compared to the flow field of the vanes-only setup. A nonnegligible modification of the probe-determined local distributions of Mach number, yaw angle, and pitch angle is revealed with respect to the undisturbed flow. Further investigation involving stagnation point tracking showed that the artificial high circumferential variation of the yaw angle is not caused by a modification of the vane outlet flow angle, but is induced by nonuniform flow conditions downstream of the vanes. With knowledge of the above, a two-step correction is used to account for the effects of the nonuniformity of the flow, and its impact is evaluated on 2D and 3D flow regions. A significative effect of the correction was found on the probe-determined yaw angle, in which the difference from the vanes-only data was reduced to below 1 deg, except near the endwalls where larger discrepancies remain due to probe–endwall interactions. A shortfall of the correction was instead observed on the probe-determined Mach numbers. Finally, the pitch-wise averaged quantities were evaluated. It was observed that the highest differences between probe-determined and undisturbed data occur where radial gradients of total pressure are stronger and that the two-step correction had almost negligible impact on the pitch-wise averaged quantities.

An efficient parametrized optical infrared thermography 3D finite element framework for computer vision applications

Matching infrared thermography (IRT) with deep learning-based computer vision has recently gained a lot of interest for automated defect assessment in materials. One of the remaining bottlenecks concerns the necessity of a large and diverse experimental and/or virtual training dataset in order to achieve a sufficiently generalizable computer vision algorithm. This paper presents a parametrized 3D finite element (FE) framework, implemented in Fortran90, for efficiently simulating optical infrared thermographic inspection of multi-layer anisotropic media and establishing large-scale virtual dataset with sufficient diversity. The interface element is introduced for the modelling of an imperfect thermal contact, allowing to simulate a variety of defect types. The flexibility of the interface element makes it possible to simulate delaminations with different thickness using the same discretized model. Validation is done for two benchmark cases which are representative for a fiber reinforced polymer laminate with delamination-like defects. In order to achieve true-to-nature thermographic simulation data, non-uniform heating conditions are adopted from experiment, and a stochastic morphology generator is introduced for modelling realistic irregular defect geometries. To demonstrate the added value of a large, diverse and true-to-nature virtual database for computer vision applications, a Faster-RCNN model was trained on a generated virtual dataset for the detection of delamination-like defects in fiber reinforced polymer laminates. Application of the trained Faster-RCNN on experimental thermographic data yields excellent inference results, illustrating the high generalization ability of the virtually trained object detector.

Marine propeller underwater radiated noise prediction with the FWH acoustic analogy Part 2: Assessment of model scale propeller hydroacoustic performance under non-uniform flow conditions

This study presents the model scale benchmark, The Princess Royal, propeller's hydrodynamic performance, including cavitation extensions and URN operating in a non-uniform wake field. The developed V-AMR technique was used in the numerical calculations to accurately solve the tip vortex flow and better representation the tip vortex cavitation (TVC) in the propeller slipstream. The sheet and tip vortex cavitation was modelled using the Schnerr-Sauer cavitation model. A hybrid method, combining the DES and permeable formulation of the FWH equation, was used for predicting the propeller URN at four different operating conditions corresponding to full-scale operating conditions. The numerical results were first validated with the experimental data obtained in the cavitation tunnel through the propeller hydrodynamic characteristics, cavitation extension and URN in model scale. Then, the propeller URN predictions using a hybrid method were extrapolated to full-scale with the ITTC extrapolation procedure to compare the numerical results with the extrapolated experimental data and full-scale measurements. The results showed that the cavitation extensions on and off the blades were satisfactorily predicted in the numerical calculations compared to the model-scale campaigns and full-scale sea trial observations. However, the same cavitation dynamics and TVC could not be predicted in conditions where the weak and incipient TVC were present between the numerical calculations and model-scale test campaign. Also, the numerical calculations underpredicted the model scale propeller URN at certain frequencies compared to model scale experimental data, except for the highest loading condition. Akin to the comparisons of model scale propeller URN between the numerical calculations and model-scale test data, the extrapolated propeller URN was generally underpredicted at a certain frequency range of the noise spectrum in the numerical calculations compared to the full-scale measurements. This underprediction in the numerical calculations can be associated with the lack of cavitation dynamics, especially TVC, compared to experimental and full-scale observations.

Numerical Investigation on Two-Phase Water Density Wave Oscillations in a Pipe under Various Heating Conditions

This study utilizes the finite volume method with a two-fluid model to analyze water characteristics in a boiling channel when density wave oscillation occurs. A 2-D numerical model is utilized to characterize both axial and radial mass and energy exchange, as well as the mechanisms involving flow and heat transfer during density wave oscillation under uniform and non-uniform heating conditions. The numerical model was used to predict the heating power threshold values of two-phase water flowing upward in a vertical pipe under type II density wave oscillation at the working pressure and an inlet–outlet pressure difference of 125 kPa, when the average heating power increased from 44.06 kW/m2 at a speed of 0.5 kW/(m2·s). The flow and heat transfer characteristics before and after the type II density wave oscillation were determined and compared to the flow and temperature fields at various moments. Along the pipe axis, the wall heat flux was loaded under uniform, standard-sine, and inverted-sine types, which represent three typical types of wall heat flux arrangements. Flow oscillation appeared the earliest under the inverted-sine-type heat flux with low vapor quality (approximately 0.13) with a void fraction of 0.6 at the outlet.

An improved genetic algorithm based fractional open circuit voltage MPPT for solar PV systems

To extract the maximum power from solar PV, maximum power point tracking (MPPT) controllers are needed to operate the PV arrays at their maximum power point under varying environmental conditions. Fractional Open Circuit Voltage (FOCV) is a simple, cost-effective, and easy to implement MPPT technique. However, it suffers from the discontinuous power supply and low tracking efficiency. To overcome these drawbacks, a new hybrid MPPT technique based on the Genetic Algorithm (GA) and FOCV is proposed. The proposed technique is based on a single decision variable, reducing the complexity and convergence time of the algorithm. MATLAB/Simulink is used to test the robustness of the proposed technique under uniform and non-uniform irradiance conditions. The performance is compared to the Perturb & Observe, Incremental Conductance, and other hybrid MPPT techniques. Furthermore, the efficacy of the proposed technique is also assessed against a commercial PV system’s power output over one day. The results demonstrate that the proposed GA-FOCV technique improves the efficiency of the conventional FOCV method by almost 3%, exhibiting an average tracking efficiency of 99.96% and tracking speed of around 0.07 s with minimal steady-state oscillations. Additionally, the proposed technique can also efficiently track the global MPP under partial shading conditions and offers faster tracking speed, higher efficiency, and fewer oscillations than other hybrid MPPT techniques.

Coupled simulation of CFD and human thermoregulation model in outdoor wind environment

Understanding of dynamic and transient wind environment is crucial to evaluating the outdoor thermal comfort of pedestrians. The thermophysiological responses of the human body depend on both the interaction with the climate and internal thermoregulation. The coupled simulation of CFD and thermoregulation model provides a pathway to predict human responses under non-uniform conditions where local effects may dominate thermal comfort. In this work, we explore the potential of coupled simulation under outdoor environmental conditions. The thermoregulation model JOS-3, which consists of 85 nodes and 17 body segments, is used to simulate the physiological responses and the obtained mean skin temperature is fed into CFD as the boundary condition of the thermal manikin. The thermal interactions between the human and surrounding environment in the wind tunnel, represented by convective and radiant heat transfer coefficient, are calculated by CFD and serve as inputs for the JOS-3 thermoregulation model. The results exhibit that under the wind velocity of 1 m/s and turbulent intensity of 11.6%, the coupling can converge within two iterations. This is because the convective heat transfer coefficient is not significantly affected by the body skin temperature under the assigned outdoor airflow velocity, which is higher than the value in an indoor environment. The study demonstrates the workflow of coupled simulation in an outdoor wind environment and could be a useful tool for evaluating outdoor thermal comfort under different conditions in the future.

InP- and GaAs-Based Photonic Power Converters Under O-Band Laser Illumination: Performance Analysis and Comparison

Photonic power converters (PPCs), which convert narrow-band light to electricity, are essential components in power-by-light systems. When designed for telecommunications wavelengths such as the O-band, near 1310 nm, the devices are well-suited to power-over-fiber applications. Despite the potential for very high power conversion efficiencies ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mathbf {&gt;50\%}$</tex-math></inline-formula> ), PPCs can be adversely affected by high-intensity nonuniform illumination conditions. In this work, we characterized two O-band PPC designs based on: high-quality InGaAsP absorber material lattice-matched to an InP substrate, and metamorphic InGaAs absorber material lattice-mismatched to a GaAs substrate, a more cost-effective and scalable alternative. We measured each device under O-band laser illumination with five beam profiles having peak-to-average ratios ranging from 2 to 11. Both devices were insensitive to the beam uniformity for input illumination with average irradiance below 2 W/cm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mathbf {^{2}}$</tex-math></inline-formula> over their 5.4-mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mathbf {^{2}}$</tex-math></inline-formula> active areas, but exhibited better open-circuit voltages under larger, more uniform illumination profiles at higher incident powers. Measured efficiencies reached 52.8% and 48.7% for the lattice-matched and mismatched devices, respectively. Distributed circuit modeling results suggested that both lateral conduction losses and localized heating effects were responsible for the measured dependence on beam-size. Our work demonstrates the potential for O-band PPCs, presenting two highly efficient designs suitable for powering devices requiring <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mathbf {\lesssim 250}$</tex-math></inline-formula> mW, with an appropriate illumination profile.