Height-width Ratio Research Articles

Relationship between 3-dimensional aortic geometry and the risk of new-onset heart failure

Abstract Introduction Aortic geometric assessments to date have typically involved cross-sectional imaging of discrete aortic segments. However, the complex 3D geometry of the thoracic aorta, and its relationship to the risk of cardiovascular disease has not been assessed in large studies. Methods We segmented the thoracic aorta in SSFP axial MRI images from 49,282 UK Biobank participants using a deep convolutional neural network (U-Net). We then computed geometric measurements (centerline length, arch height, arch width, arch height-width ratio, arch unfolding index [inverse of tortuosity], curvature and mean, minimum and maximum diameters) in the overall thoracic aorta as well as in 6 subsegments. We quantified their relationship to the risk of cardiomyopathy and heart failure (HF) using multivariable Cox-proportional hazards models. All hazard ratios are standardized. Centerline length was allometrically indexed to body height. Results In models adjusted for age, sex, BMI kg/m2, low-density lipoprotein mg/dl, high-density lipoprotein mg/dl, triglycerides mg/dl, systolic blood pressure and diastolic blood pressure, the curvature of the aorta (HR=0.63; 95% CI=0.39, 0.99; P<0.05), particularly the aortic arch (HR=0.54; 95% CI= 0.35, 0.87; P<0.05) was strongly related to a lower risk of incident cardiomyopathy. A higher arch unfolding index (HR=1.46; 95% CI=1.03, 2.07; P<0.05), higher width-to-height ratio (HR=1.10; 95% CI= 1.02, 1.19; P<0.05) and lower aorta tortuosity (HR=1.20; 95% CI= 1.09, 1.32; P<0.05) were all associated with a higher risk of cardiomyopathy. This aortic geometric pattern was also associated with a greater risk of a new HF diagnosis (arch unfolding [HR=1.23; 95% CI= 1.07, 1.42; P<0.05], width to heigh ratio [HR=1.06; 95% CI= 1.01, 1.11; P0.05]). Conclusion We demonstrate that 3-D thoracic aortic geometric indices are strongly associated with incident cardiomyopathy and HF, independent of classic risk factors. This is likely related to abnormal afterload and ventricular-arterial interactions since adverse geometric remodeling affects left ventricular pulsatile load.Cardiomyopathy & Heart Failure Hazards

Genome wide association studies on three-dimensional aortic geometric indices measured with magnetic resonance imaging

Abstract Introduction To date, three-dimensional properties of the aorta have not been comprehensively quantified in a population level dataset, nor has there been a genome-wide association study (GWAS) to identify significant single nucleotide polymorphisms (SNPs) associated with geometric properties of the aorta. Methods We segmented the thoracic aorta of 48,045 subjects in the UK Biobank using a U-Net convolutional neural network. We then computed geometric measurements (centerline length, arch height, arch width, arch height-width ratio, curvature, and mean, minimum and maximum diameter) across six subsegments of the aorta. Centerline length was allometrically indexed to body height. Using generalized linear models, we performed GWAS on each geometric phenotype adjusted for the following covariates: (1) age, (2) sex, and (3) ten genetic principal components. SNPs with a minor allele frequency < 0.05 were excluded. We performed LD-based clumping with an r2 threshold of 0.001 to identify significant loci and used LDSC to compute the genetic heritability of each geometric phenotype. Results After performing LD clumping, we identified 457 significant(P<5e-8) SNPs across 36 aortic geometric parameters. GWAS-based heritability analyses showed a mean heritability of 13.8 (9.9) % across all aortic geometric parameters, with all intercepts being close to 1, suggesting minimal genomic inflation. Maximum aorta diameter exhibited the highest observed heritability of 34.5 (3.0) %. Allometric centerline length showed a heritability of 13.6 (1.5) %. Similarly, arch height and width showed heritability of 14.6 (1.5) %, and 13.64 (1.5) % respectively. Aortic curvature showed limited heritability at 8.54 (1.2) %, with arch curvature being further reduced to 7.6 (1.20) %. Conclusion To our knowledge, this was the first study that investigated the genetic architecture of aortic centerline length, aortic curvature, and aortic tortuosity. These results suggest that aortic remodeling associated with aging and pathological conditions has important genetic contributions. SNPs associated with aortic geometry may identify therapeutic targets to prevent aortic remodeling, which should be the focus of future work.significant_snpsheritability

Horizontal shaking table tests on a four-story prototype structure using multi-dimensional earthquake isolation and mitigation devices

Three-dimensional isolation system (3DIS) has been increasingly applied to civil structures with small height-width ratios, but is rarely employed in the multistory and high-rise buildings due to the lack of efficient control strategy for the rocking effect. In this paper, a simplified analysis model of 3DIS was established firstly to bring insights into the coupled motion mode caused by the rocking effect, and the influence of damping ratio and height-width ratio on the modal frequency was revealed. Then, aimed at weakening rocking motion and improving the seismic isolation efficiency, a novel multi-dimensional earthquake isolation and mitigation device (MEIMD) was proposed, and both the design composition and design principle were given in detail. To validate the effectiveness of MEIMDs, a full-scale four-story frame with a height of 13.05 m and a weight of 70 tons was produced for horizontal shaking table tests. The experimental results indicated that after adopting MEIMDs, the first-order modal frequency was 1.7 Hz, with 68% decrease compared with that of the prototype structure, and the first-order modal damping ratio was above 0.23, about eight times that of the prototype structure. Moreover, the horizontal peak acceleration was significantly decreased for each floor with a maximum reduction of 49%, while the maximum horizontal displacement and rocking response were obviously lower than the limit value specified by building codes. Therefore, the MEIMDs can not only efficiently isolate the earthquake energy, but also ensure the sufficient dynamic stability of the system. This study sheds light on the real coupled horizontal-rocking response of the base isolation system with MEIMDs, and can promote the development and application of 3DIS in multistory and high-rise buildings.

Restoring force model of phosphogypsum-filled cold-formed thin-walled square steel tube composite wall

The phosphogypsum (PG)-filled cold-formed thin-walled square steel tube (PFCFS) composite wall is a new type of cold-formed steel (CFS) wall. The restoring force model (including the skeleton curve and hysteresis rules) is an important performance of this type of walls. Based on the characteristics of load–displacement curves of the walls, a Pinching4 model for the skeleton curve of the walls is developed. The lateral stiffness and shear capacity of the walls are calculated by theoretical formulas, while other parameters are determined through data fitting. Moreover, the hysteresis rules of the walls adopt the Pivot model, and the Pivot parameters (α and β) of the walls are determined based on the principle of equal energy. Finally, based on the above restoring force model, the energy dissipation analysis for the walls with different parameters was conducted. The results show that improving the PG strength, stud thickness, or reducing the height-width ratio of the walls significantly enhances the energy dissipation capacity of the wall; increasing the OSB thickness, axial force ratio, or reducing the screw spacing gradually improves the energy dissipation capacity of the wall; the OSB configuration and the stud strength have a smaller impact on the energy dissipation of the wall; the energy dissipation capacity of the wall when the hold-down fails is lower.

Performance of multi-ribbed composite wall incorporating reactive powder concrete-filled steel tubular columns under axial compression

In this study, axial compression researches of an innovative composite shear wall, named multi-ribbed composite wall incorporating reactive powder concrete-filled steel tubular columns, were conducted using theoretical analyses as well as experimental and numerical investigations. This precast hybrid system embedded reactive powder concrete-filled steel tubular columns as boundary elements of multi-ribbed composite wall. A novel approach, namely the unified strength theory, was adopted in consideration of various materials diversity. The outcomes of unified strength theory were utilized to predict the ultimate compressive capacity of multi-ribbed composite wall equipped with reactive powder concrete-filled steel tubular columns. The proposed theoretical formulas were validated against the experimental results reported in this paper. Despite the fact that the calculated formula with b= 0 was obtained to predict the closest capacity value of the test specimen infilling ordinary concrete. The calculations with different values of b clearly indicated that the intermediate principal stress effect should be rationally considered. Experimental observations suggested that the frame column significantly contributed to improving the compressive performance throughout the entire process and maintained the wall integrity. Meanwhile, finite element models were developed using the ABAQUS program, followed by the elaboration of its numerical implementation. The numerical predictions of ten shear wall specimens infilling reactive powder concrete were found to be reasonably in agreement with the calculated results corresponding to b= 0.5. These findings revealed the characteristics of multiple defensive lines of "block-ribbed column-frame column" under axial compression. Following the successful validation of finite element models, parametric studies were carried out to evaluate the influences of the filled block compressive strength, steel tube wall thickness and height-width ratio. The results show that the axial compression capacity of multi-ribbed composite wall incorporating reactive powder concrete-filled steel tubular columns can be noticeably improved with an increase in block strength and tube thickness. The proposed composite wall demonstrates favorable cooperative working performance and desirable displacement ductility. Subsequently, the primary objective of this pilot study aimed at developing a reliable theoretical calculation formula and conducting numerical simulation verification of the innovative composite wall. The aforementioned conclusions are intended to provide insights for the guidance and optimization of engineering structures.

Numerical Study on Failure Mechanisms of Deep Roadway Sidewalls with Different Height-Width Ratios and Lateral Pressures

The stability of roadway sidewalls is crucial to ensuring people’s safety and production efficiency in coal mining. This paper investigated the deformation and failure of deep roadway sidewalls, particularly the effects of height-width ratios and lateral pressure coefficients. Our research results indicate that brittle failure occurred in the diabase sidewall rock of the Datai coal mine, and a V-shaped pit was formed as a result of shear damage caused by high stress. When the height-width ratio of a roadway increases from 0.25 to 2.00, the tensile and shear plastic failure area of the sidewall increases, and vertical stress is transferred to a deep part of the roadway sidewall. There are two stress concentration zones and two stress peak points in the sidewall of a roadway. When the lateral pressure coefficient increases from 0.10 to 1.00, the tensile plastic zone of rock mass in the sidewall first decreases and gradually reaches stability. On the other hand, the shear failure area increases and then decreases. Similarly, the sidewall horizontal displacement decreases and then increases. Additionally, the vertical stress concentration position is located near the roadway sidewall.

Regional Lineament Pattern and Morphotectonic Analysis: The Investigation of Geological Structures and Present-Time Relative Tectonic Activity in the Tin Granite Area of Belitung Island, Indonesia

Belitung Island is located on the East Coast of Sumatra and is the southernmost extension of the Southeast Asian granite belt. Despite the flat terrain of the island, numerous granite outcrops provide insight into the past tectonic activities that caused the uplift in the region. This study analyzes the current state of Belitung's tectonic activity by examining its morphotectonic index and lineament pattern. A National Digital Elevation Model (DEMNAS) dataset with a resolution of up to 8.1 m will be used to assess the geological patterns and relative tectonic activity from the surface. The relationship between the regional lineament system and morphotectonic quantification throughout the landforms of Belitung Island will also be considered. The modified Segmented Tracing Algorithm (m-STA) technique extracted the lineament features. The Index of Relative Active Tectonic (IATR) was calculated by averaging several morphotectonic indices, such as asymmetry factors (AF), stream-length index (SL), mountain-front sinuosity (Smf), and valley floor width-height ratio (VF) factors, to quantify the relative tectonic activity of the area. The combination of the two methods shows that Belitung is currently experiencing relatively weak tectonic activity compared to the past. This is supported by the surface appearance, which is mainly composed of lowlands. Several granite outcrops and highlands are aligned along the NW-SE and NE-SW directions, corresponding to the main geological structures in the area.

Fire behavior of full-scale cold-formed steel center-sheathed shear walls under combined loads

An innovative cold-formed steel center-sheathed shear walls (CFSCSSWs) was proposed in this paper to improve the horizontal load-carrying capacity of conventional cold-formed steel walls. However, the fire behavior of this wall configuration was particularly worthy of attention because it was designed to be used in multi-story buildings, and there is still a lack of in-depth exploration of the fire performance and high-temperature horizontal load-bearing capacity of CFSCSSWs under combined loads. In this study, a compression test was first carried out to obtain the vertical load-carrying capacity of a full-scale CFSCSSW, followed by a fire test on a similar CFSCSSW subjected to combined vertical and horizontal loads to investigate the fire behavior of walls. Then, a finite element model was established and validated by test results to investigate the influence of various critical factors, including vertical and horizontal load ratios, height-width ratio, and sheathing thickness, on the fire behavior of the CFSCSSW. The results showed that the vertical load ratio presented a larger influence on the fire behavior of CFSCSSWs compared to the horizontal load ratio. The increasing aspect ratio can slightly improve the fire resistance of the wall under the same load ratio. The wall with a 0.8 mm thick sheathing exhibits better fire behavior under the same load ratio. A high-temperature horizontal load-carrying capacity calculation method for CFSCSSWs was proposed, and its good accuracy was found.

Building Structural Design Innovation and Code Development

In recent years, Some new structural systems and design difficulties of high-rise and super high-rise buildings were emerged in Shenzhen, such as forced displacement and non-forced displacement, story lateral stiffness calculation method, frame-core wall structures with partial perimeter frame beams missing, super high-rise structure with great height-width ratio, high-rise less shear walls in one direction structure, conjoined tower structures, high-rise structure with inclined column, mega structure with belt truss, rare earthquake design method etc. The emergence and solution of these problems reflect the innovation of the structural design of high-rise buildings. Meanwhile, Structural design has encountered many difficulties and new problems. The solutions to these problems sometimes conflict with the current Chinese code, or there are no relevant provisions in the Chinese code. The current Chinese code is the basis for designing of high-rise buildings, which is the crystallization of the wisdom of previous generations, but the emergence of various new types of building structures has brought about numerous difficulties in structural design. Therefore, during the design process, it is necessary to conduct research, innovation, supplementation, and development of the current code. In view of this situation, this paper combines the previous engineering practical experience and introduces some structural design points of complex super high-rise buildings located in Shenzhen. It is for designers' reference, which also provides content for the revision of the specification.

Intracranial Aneurysms in Makassar, Indonesia: Unveiling Rupture Risk Characteristics

Intracranial Aneurysms in Makassar, Indonesia: Unveiling Rupture Risk Characteristics

Limit equilibrium model for active failure of large-size rectangular tunnel face considering effect of height–width ratio

The stability of a rectangular tunnel face (RTF) has received less attention than that of circular tunnels; in particular, the stability of RTFs with different height–width (H/W) ratios has not yet been investigated comprehensively. In this study, extensive numerical simulations are conducted to investigate the limit support pressure (Pa) of the active failure of an RTF with different H/W ratios and to determine the appropriate failure mechanism without assuming the failure shape in advance. The result shows that, as the H/W ratio increases, Pa decreases gradually for specified heights and overburden depths of the RTF. The failure shape of the soil in front of the RTF is determined by analyzing the contours at plastic points of the soil. Subsequently, three types of failure modes, namely, partial semicircular, semicircular, and supersized semicircular modes, are identified based on the progression of plastic points in the soil. Corresponding failure models are established using the limit equilibrium method. Compared with relevant theoretical models, the proposed model predicted results that are more consistent with the numerical simulation results. Furthermore, a parametric study is performed to investigate the stability of the RTF. Finally, the predicted results are compared and analyzed with the pressure monitored inside the chamber, thus providing a theoretical reference for the jacking construction of the Shasan project.

Computational Simulation of Wind Loads on Three Curved Eave Models with Different Height-Width Relationships

This work deals with the effects of wind loads on two industrial shed models with curved eaves aspect of different height-to-width ratios. Using Ansys Workbench software, the external pressure coefficients for the entire roof by applying refinement levels were determined. Also were studied the quality of the unstructured and tetrahedral grid according to recommendations to ensure greater efficiency in the simulation results. The results generated provided evidence that the wind in the transverse direction is more damaging in the windward region: for a wind at 45º the most critical region appeared both windward and leeward in the model with a ratio of h/b=0.5 (Model 1) and to windward in the models with a ratio of h/b=1 (Model 2) and h/b=1.5 (Model 3). The leeward suctions increased due to the reduction in the height-width ratio considering a wind direction of 45º. The increase in this ratio intensified the values of the external pressure coefficients in the windward region for the 90º wind direction.

Mathematical analysis and process optimization of wire and arc additive manufactured Ti6Al4V ELI alloy with in-situ rolling

The combination of wire and arc additive manufacturing (WAAM) and rolling offer the advantages of high efficiency, low cost, and fine grain, making it a viable option for the rapid production of aerospace thin-wall forgings using titanium alloy. However, the interplay between various factors such as temperature gradient, deformation force, and prior pass morphology directly influence the morphology and grain evolution before and after subsequent pass deformations, which lead to insufficient overall morphological accuracy and grain refinement uniformity. Building upon theoretical analysis, numerical simulation, and experimental verification, this study focuses on investigating the metal flow behavior and grain evolution mechanism during WAAM with in-situ rolling single-pass multi-layers. By establishing correlations between morphology, microstructure, temperature, stress-strain and deformation characteristics, the process optimization strategies of large width-height ratio, shallow melting depth and fixed width spread were proposed. These findings can provide theoretical support for the deformation machine design and the high-precision, uniformly fine grains additive manufacturing of thin-walled titanium alloy forgings.

Average surface wind pressure surrounding tall buildings with cruciform shapes

Abstract Building shape affects wind pressure on building surfaces, while limited studies have examined how building shape affects the wind pressure on cruciform-shaped tall buildings. This article investigated the variation of the average wind pressure coefficient (AWPC) on cruciform-shaped tall buildings with the height–width ratio (HWR) and height–thickness ratio (HTR). The results demonstrated the occurrence of building blockage, wind separation, wind re-circulation, and wind re-attachment on building surfaces. The frontal surface of the main building was always the windward surface with positive wind pressure. At 2/3 of the building height (H), the peak AWPCs in all scenarios were ~0.70. However, in the case with an HWR of 3.66, the side surfaces of the main building and the frontal surfaces of the branch building, wind pressure was all negative. With the HWR reduction by building width increase, wind pressure on these surfaces became positive, where the AWPCs in the HWR = 1.41 case were 0.60–0.63 and 0.64–0.69 on side and frontal surface, respectively. With the HWR decrease, both positive and negative wind pressure intensified. Along the central axis (M1) in the vertical direction, wider buildings had stronger positive wind pressure on the frontal surfaces below 0.10H, while narrower buildings had stronger positive wind pressure above 0.82H. In comparison, HTR made limited differences to the wind pressure on the frontal surface. Overall, vertical results showed that scenarios with smaller HWR underwent stronger positive and negative wind pressures. On the HTR cases, wind pressure on top surfaces showed complicated results, while thicker buildings had weaker negative wind pressure on the back surface. Overall, this study is important to understand the characteristics of wind load on cruciform-shaped tall buildings and generate implications for wind resistance, natural ventilation design, and wind electricity generation over tall buildings.

Study on generating rolling method for manufacturing cylindrical parts with external cross ribs

As the main structure of launch vehicle, cylindrical parts with reinforced ribs are mainly manufactured by milling, rolling and welding methods, which have a long manufacturing cycle and low material utilization. This paper proposes a new generating rolling method for manufacturing cylindrical parts with external cross ribs integrally. The generating rolling device is developed, the flow mechanism of cylindrical parts with external cross ribs is revealed and methods to minimize the underfill defects of ribs are proposed. Simulation and experiment results show that longitudinal rib is mainly formed by gradual material accumulation in the groove under circumferential compressive strain, and transverse rib is mainly formed by gradual material accumulation in the groove under axial compressive strain. Compared with longitudinal or transverse rib, the material flow of cross rib is more difficult due to small circumferential and axial compressive strain, resulting in the underfill phenomenon. Rib structure also affects the flow of material. When the rib sparsity is large or the height-width ratio is small, the rib is subjected to small radial tensile strain and circumferential compressive strain, resulting in low rib height and uneven rib filling. The proposed forward and reverse rolling method and billet preforming method can reduce the defects of uneven filling of longitudinal rib and underfill of cross rib.

Seismic Responses of Large Height-Width Ratio Liquid Storage Structure with Base Isolation and Baffles

Seismic Responses of Large Height-Width Ratio Liquid Storage Structure with Base Isolation and Baffles

Flow Field Analysis of a Turbulent Channel Controlled by Scalloped Riblets

Riblets are small protruding surfaces along the direction of the flow, and are one of the most well-known passive turbulent drag reduction methods. We investigated a scalloped riblet, the shape of which was constructed by smoothly connecting two third-order polynomials and was not as sharp in the tip as corresponding triangular riblets with the same height-width ratio. Numerical simulations were performed for turbulent channel flow with and without riblet control at an estimated optimum width of W+=20 and a height-width ratio of 0.5. A drag reduction rate of 5.77% was obtained, which is generally larger than the reported drag reduction rates of corresponding triangular riblets from the literature. Mean flow fields and second-order statistics of velocity, vorticity, and Liutex, a quantity introduced to represent vortices, were reported. It was found that streamwise vortices just above the riblet tips, which have a length scale of 200−300 in wall units, have an important influence on those statistics and thus the turbulence generation cycle and the drag reduction mechanism. Pre-multiplied energy spectra of streamwise velocity and the Liutex component were reported to reveal the length scales in the flow field. Instantaneous vortical flow fields visualized by the Liutex method were provided with emphases on the streamwise vortices just above riblet tips. It should be noted that the class of scalloped riblets is suitable for investigations on the influences of curvatures at the tip and the valley of the riblet in future.

A study on the demographic differences in visual impact assessments of the external space of electric vehicle battery swapping stations

The construction of electric vehicle (EV) battery swapping stations (BSS), which exerts an increasingly significant impact on urban landscapes. In addition, the external space of BSS is an important means to display corporate image and brand publicity. In this experiment, a sample of nine representative BSS in China, characterized by diverse architectural forms, was selected for the examination of their exterior spaces. The study focused on the physical factors of the BSS, specifically the exterior contour, number and position of entrances, façade material, height-width ratio of front elevation, logo area ratio, and hue as key factors under investigation. Meanwhile, five demographic features, namely, gender, age, education level, EV owner or potential owner, and income level, were set as variables to study the influence of the six physical factors of external space on people's visual impact assessment. The photo stimulation method was used in this experiment. The results show that the above six physical factors affect people's visual impact assessment of the external space of BSS, and people with different demographic features render different visual impact assessments. Therefore, we propose several design recommendations for BSS exterior spaces. In BSS exterior space design, greater consideration should be given to using vertical facade aspect ratios between 1/3 and 1/2, facades combining metal and glass, smaller logo area proportions, and designs combining warm and neutral color tones to meet the visual preferences of a broader audience. Different exterior design schemes should also be adopted when BSSs are targeted at different primary user groups.

External validation and reliability assessment of posterior urethral morphology on initial voiding cystourethrogram as a predictor for infants with posterior urethral valves

The morphology of the bladder and posterior urethra on initial voiding cystourethrogram (VCUG) in posterior urethral valve (PUV) has been proposed as a meaningful early metric for short- and long-term kidney outcomes. Here, we seek to externally validate the proposed association and assess the reliability of PUV morphology characteristics. We reviewed our institutional database for patients managed for PUV between 2000 and 2022 and included those treated with primary ablation with at least 1 year of follow-up for kidney function. Each VCUG was evaluated by three independent raters for the height-width ratio of the bladder (HW-B), height-width ratio of the posterior urethra (HW-PU), and posterior-anterior urethral ratio (PA-UR), and trabeculation (none, fine, or coarse). We assessed the reliability in these with intra-class coefficient and Fleiss kappa for continuous and categorical data, respectively. We performed univariate analysis with nadir creatinine and five-year follow-up glomerular filtration rate (GFR). In total, 98 patients met inclusion criteria. The median age at diagnosis and ablation was 10 and 21 days, respectively. Patients with nadir creatinine <0.8mg/dL had higher follow-up GFR (101 vs. 20ml/min/1.73m2, p=0.04), and lower risk of CKD (odds ratio 14.7, p=0.002). The median value for HW-B was 1.4, median HW-PU was 2.1, and median PA-U was 4.7, There was significant inter-class agreement between all three measures of 0.80, 0.51, and 0.70 (p<0.001). The inter-rater agreement for bladder trabeculation was fair (Fleiss K=0.40, p<0.001). There was no statistically significant correlation between HW-B, HW-PU, PU-A with nadir creatinine (p=0.07, 0.33, 0.91) or 5-year GFR (0.27, 0.45, 0.62), respectively. There is significant interest in determining prognostic factors and metrics in PUV. The morphological characteristics on VCUG are reliable and is available information for all boys diagnosed with PUV, resulting in an attractive metric. While we do not demonstrate correlation with kidney outcomes, VCUG features warrant further attention as prognostic factors in PUV. PUV morphology on initial VCUG is a reliable metric of lower urinary tract deformity but is not associated with 5-year kidney outcomes.

Multi-objective optimization of rectangular microchannel heat sink based on entropy generation and hydro-thermal performance using NSGA-II algorithm

In this study, multi-objective optimization of a rectangular microchannel heat sink is implemented based on two objective functions figure of merit (FOM) and entropy generation (Ṡgen). Decision variables are height ratio (α), width ratio (β) and number of channels (N). CFD simulations are conducted for different values of decision variables and the effects of each decision variable on hydro-thermal performance (FOM) and entropy generation are studied separately. To reduce the computational cost in multi-objective optimization process, a fourth-order multivariate polynomial regression model is used to predict the FOMαβ and Ṡgenαβ objective functions at each N. Non-Dominated Sorting Genetic Algorithm II coupled with predicted objective functions (FOM and Ṡgen) is implemented to maximize the FOM and minimize the Ṡgen at each N. Also, the decision variables related to the highest FOM are presented, which is 90% more than the reference point, and the hydrodynamic-thermal performance has improved. Decision variables related to the lowest Ṡgen are presented, which is 19% lower than the reference point. Finally, decision variables are presented to simultaneously satisfied the highest FOM and the lowest Ṡgen where FOM is 57% higher than the reference point and Ṡgen is 9.78% lower than the reference point.