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Background: Asthma is an inflammatory disease. The potential of omega-6 fatty acids to alleviate asthma symptoms through their anti-inflammatory and immunomodulatory effects has been investigated. However, the association of dietary omega-6 fatty acids in childhood and adolescent asthma remains controversial. Objective: The aim of this study was to evaluate the association between dietary intake of omega-6 fatty acids and asthma in children and adolescents in the United States. Methods: We conducted a cross-sectional analysis of 5045 children and adolescents from the National Health and Nutrition Examination Survey (NHANES) between 2013 and 2020. Covariates were adjusted, and multivariate logistic regression, restricted cubic splines, threshold effects, and subgroup analyses were used. Results: Of the 5045 participants, 1000 (19.8%) were identified as having asthma. After adjustment for potential confounders, individuals in the second group (T2, 215.3-377.7 mg/kg/day) had an adjusted odds ratio (OR) of 0.70 (95% CI: 0.57–0.86, P = 0.001) for asthma compared with those in the lowest omega-6 fatty acid intake group (T1, < 215.3 mg/kg/day). Similarly, individuals in the third group (T3, > 377.7 mg/kg/day) had an adjusted OR of 0.59 (95% CI: 0.45–0.78, P < 0.001) for asthma. Furthermore, a non-linear (L-shaped) relationship between omega-6 intake and asthma was observed (P = 0.001), with subgroup analyses confirming the stability of the results. In the threshold analysis, a critical turning point was observed at around 384.2 mg/kg/day (OR = 0.996, 95% CI: 0.995–0.998, P < 0.001). Conclusion: The consumption of omega-6 fatty acids in the diet showed an L-shaped association with asthma among children and adolescents in the United States. A critical turning point was noted at approximately 384.2 mg/kg/day. Key message: 1. L-shaped association between dietary omega-6 intake and asthma in US children. 2. Notable turning point at 384.2 mg/kg/day suggests an optimal omega-6 intake for asthma protection. 3. Findings emphasize the need for nuanced dietary recommendations to reduce childhood asthma risk. [ABSTRACT FROM AUTHOR]

The manuscript presents the design and investigation of square and L-shaped graphene plasmonic nano-antenna arrays on a silicon dioxide substrate for plasmonic biosensing applications. The design parameters, such as the shape of the nanostructure, spacing between the antenna array elements, size of the antenna array and chemical potential of the graphene are used to analyze the plasmonic resonance characteristics of the proposed plasmonic nano-antenna array. Initially, dispersive characteristics of graphene, such as conductivity, permittivity and refractive index are analyzed using its chemical potential for the validation of the graphene material for plasmonic sensing applications. The proposed square and L-shaped nanopatch antenna structures are radiating at 30 THz with a reflection coefficient of -28.4 dB and − 44.6 dB respectively at 0.1 eV chemical potential. It is observed that graphene nanopatch antenna radiates at 30 THz, 115 THz and 176 THz at a chemical potential of 1.3 eV. Further, the study demonstrated that the designed square and L-shaped nano-antenna exhibit a gain of 3.52 dB and 9.51 dB respectively at 30 THz. The gain can be increased further using a square and L-shaped nano-antenna array of dimensions 2 × 2, 3 × 3 and 4 × 4. It is observed that maximum gains of 33.44 dB and 30.86 dB are obtained for the square and L-shaped 4 × 4 plasmonic nanoarray antenna respectively. Finally, a nanocircuit model of square and L-shaped nano-antennas is proposed and validated through CST simulations. [ABSTRACT FROM AUTHOR]

The L-shaped partially encased steel–concrete composite (PEC) stub column, composed of profile steel, concrete, and transverse links, tends to occupy less space than the rectangle-shaped PEC column when used as side or corner columns. In this study, an axial compression test involving three L-shaped PEC stub columns was conducted to investigate the influence of critical factors on axial compression performance. The test results indicated that the axial compression capacity can be effectively enhanced with an increase in material strength. Furthermore, finite element (FE) analysis was carried out with parameters such as material strength, steel thickness, transverse link spacing, transverse link diameter, transverse link distribution, and longitudinal rebar diameter. The results revealed that the primary failure modes of L-shaped PEC columns were concrete spalling and local buckling of the flange. Additionally, it was found that the increase in steel strength, steel thickness, and transverse link diameter, as well as the decrease in transverse link spacing, significantly improved the axial compression capacity and concrete confinement effect. However, an increase in concrete strength diminished the concrete confinement effect. Additionally, the accuracy of the axial compression capacity calculation methods in the Eurocode 4 and T/CECS719-2010 specifications for L-shaped PEC stub columns was verified. Finally, a calculation method based on the superposition principle incorporating the concrete confinement effect was proposed, and validated by comparing with experimental and FE results. Overall, this study could provide a theoretical basis for the engineering application of L-shaped PEC columns. [ABSTRACT FROM AUTHOR]

Abstract Background Asthma is an inflammatory disease. The potential of omega-6 fatty acids to alleviate asthma symptoms through their anti-inflammatory and immunomodulatory effects has been investigated. However, the association of dietary omega-6 fatty acids in childhood and adolescent asthma remains controversial. Objective The aim of this study was to evaluate the association between dietary intake of omega-6 fatty acids and asthma in children and adolescents in the United States. Methods We conducted a cross-sectional analysis of 5045 children and adolescents from the National Health and Nutrition Examination Survey (NHANES) between 2013 and 2020. Covariates were adjusted, and multivariate logistic regression, restricted cubic splines, threshold effects, and subgroup analyses were used. Results Of the 5045 participants, 1000 (19.8%) were identified as having asthma. After adjustment for potential confounders, individuals in the second group (T2, 215.3-377.7 mg/kg/day) had an adjusted odds ratio (OR) of 0.70 (95% CI: 0.57–0.86, P = 0.001) for asthma compared with those in the lowest omega-6 fatty acid intake group (T1, 377.7 mg/kg/day) had an adjusted OR of 0.59 (95% CI: 0.45–0.78, P

Abstract The systemic immune-inflammation index (SII), an integrated and ground-breaking inflammatory measure, has been widely used in various fields. We aimed to assess the association between the systemic immune-inflammation index (SII) and α-Klotho (a new anti-aging biomarker). In this cross-sectional investigation, people with complete information on SII and α-Klotho from the National Health and Nutrition Examination Survey (NHANES) between 2007 and 2016 were the study's subject population. SII was calculated by platelet count × neutrophil count/lymphocyte count. The association between SII and α-Klotho was investigated using multivariable linear regression and a generalized additive model. In order to explore the non-linear connection, we employed smoothed curve fitting. Subgroup analysis were also performed. A total of 13,701 participants with an average age of 57.73 ± 10.86 years were enrolled, of whom 51.53% were female. After fully adjustment, SII was negatively associated with serum soluble α-Klotho [β(95% CI) = − 0.07 (− 0.08, − 0.05)]. Furthermore, we found L-shaped association between SII and klotho protein level, with the inflection point at 255 pg/ml. Subgroup analysis and interaction test revealed that there was no discernible dependence on gender, age, race, smoking, alcohol, diabetes and hypertension (all p for interaction > 0.05). SII level was negatively associated with serum klotho protein concentration in American adults. To verify our findings, more large-scale prospective investigations are still required.

The systemic immune-inflammation index (SII), an integrated and ground-breaking inflammatory measure, has been widely used in various fields. We aimed to assess the association between the systemic immune-inflammation index (SII) and α-Klotho (a new anti-aging biomarker). In this cross-sectional investigation, people with complete information on SII and α-Klotho from the National Health and Nutrition Examination Survey (NHANES) between 2007 and 2016 were the study's subject population. SII was calculated by platelet count × neutrophil count/lymphocyte count. The association between SII and α-Klotho was investigated using multivariable linear regression and a generalized additive model. In order to explore the non-linear connection, we employed smoothed curve fitting. Subgroup analysis were also performed. A total of 13,701 participants with an average age of 57.73 ± 10.86 years were enrolled, of whom 51.53% were female. After fully adjustment, SII was negatively associated with serum soluble α-Klotho [β(95% CI) = − 0.07 (− 0.08, − 0.05)]. Furthermore, we found L-shaped association between SII and klotho protein level, with the inflection point at 255 pg/ml. Subgroup analysis and interaction test revealed that there was no discernible dependence on gender, age, race, smoking, alcohol, diabetes and hypertension (all p for interaction > 0.05). SII level was negatively associated with serum klotho protein concentration in American adults. To verify our findings, more large-scale prospective investigations are still required. [ABSTRACT FROM AUTHOR]

Objective To compare the clinical outcomes of a modified arthroscopic triple‐row (TR) repair technique with the suture bridge (SB) repair technique in treating L‐shaped delaminated rotator cuff tears. Various surgical techniques for L‐shaped delaminated rotator cuff tears have been reported, many of which aid in increasing the contact area and pressure of the rotator cuff. However, there is still debate over which technique yields superior results. Methods From January 2017 to March 2020, 61 cases of L‐shaped delaminated rotator cuff tears were included in this study. Of these, 34 cases underwent the modified arthroscopic triple‐row repair technique, while 27 cases were addressed with the suture bridge repair technique. Functional assessment was conducted using the American Shoulder and Elbow Surgeons (ASES) score, the University of California Los Angeles (UCLA) shoulder score, the Constant score (CS), and the visual analogue scale (VAS) score. Magnetic Resonance Imaging (MRI) assessments for rotator cuff healing were performed at the 24‐month postoperative mark. Statistical evaluations were conducted using SPSS for Windows (Version 25.0, IBM, Armonk, NY, USA), employing the Wilcoxon signed‐rank test to compare preoperative and postoperative data and ROM differences, and the Mann–Whitney U test for statistical differences in clinical outcome scores between the two groups. A p‐value of less than 0.05 was considered statistically significant. Results Comparative analysis of the preoperative and final follow‐up scores revealed a substantial enhancement in shoulder function, as indicated by the ASES, UCLA, CS, and VAS scores, with statistical significance (p

Background Chronic kidney disease (CKD), which has become a global public health issue, is associated with mitochondrial dysfunction. Niacin is a necessary coenzyme for mitochondrial energy metabolism. However, the association between dietary niacin intake and CKD remains uncertain. This study aimed to investigate the association between dietary niacin intake and CKD in American adults.Methods This is a cross-sectional study. 25,608 individuals aged ≥20 years from the National Health and Nutrition Examination Survey from 2007 to 2018 were involved.Dietary niacin intake was estimated based on 24-hour dietary recalls conducted by trained personnel. CKD was determined by an estimated glomerular filtration rate (eGFR) (

Objective: To compare the clinical outcomes of a modified arthroscopic triple‐row (TR) repair technique with the suture bridge (SB) repair technique in treating L‐shaped delaminated rotator cuff tears. Various surgical techniques for L‐shaped delaminated rotator cuff tears have been reported, many of which aid in increasing the contact area and pressure of the rotator cuff. However, there is still debate over which technique yields superior results. Methods: From January 2017 to March 2020, 61 cases of L‐shaped delaminated rotator cuff tears were included in this study. Of these, 34 cases underwent the modified arthroscopic triple‐row repair technique, while 27 cases were addressed with the suture bridge repair technique. Functional assessment was conducted using the American Shoulder and Elbow Surgeons (ASES) score, the University of California Los Angeles (UCLA) shoulder score, the Constant score (CS), and the visual analogue scale (VAS) score. Magnetic Resonance Imaging (MRI) assessments for rotator cuff healing were performed at the 24‐month postoperative mark. Statistical evaluations were conducted using SPSS for Windows (Version 25.0, IBM, Armonk, NY, USA), employing the Wilcoxon signed‐rank test to compare preoperative and postoperative data and ROM differences, and the Mann–Whitney U test for statistical differences in clinical outcome scores between the two groups. A p‐value of less than 0.05 was considered statistically significant. Results: Comparative analysis of the preoperative and final follow‐up scores revealed a substantial enhancement in shoulder function, as indicated by the ASES, UCLA, CS, and VAS scores, with statistical significance (p < 0.001). At both the preoperative stage and final follow‐up, no notable differences were observed in ASES, UCLA, CS, and VAS scores between the two groups. However, the TR repair group exhibited lower VAS scores than the SB group at 1 and 3 months postoperatively. Active range of motion (ROM) showed significant improvement in both groups. No significant differences in ROM were noted between the two groups either before the surgery or at the final follow‐up. Conclusion: The study demonstrates that both the modified arthroscopic TR and SB techniques for L‐shaped delaminated cuff tears yield satisfactory outcomes, with no significant differences in overall clinical performance. Notably, early postoperative pain management appears more effective with the modified TR technique, suggesting its potential for enhanced early recovery experiences. This technique's design, promoting securer fixation and optimal contact conditions, is implied to facilitate superior long‐term healing, warranting further investigation into its long‐term benefits. [ABSTRACT FROM AUTHOR]

• A dynamic model of L-shaped fluid-conveying pipes based on ANCF method is established. • Effects of the radius of the arc section and the fluid velocity on the natural frequency are discovered. • Results of the ANCF method are verified by results obtained by the experiment and simulation. In this study of fluid-conveying pipe dynamics, it is usually assumed that the shape of the pipe is straight. This paper establishes a flow-induced vibration model of an L-shaped pipe based on the absolute nodal coordinate formulation (ANCF), and mainly studies the effects of fluid velocity, structural parameters, and boundary conditions on the vibration characteristics of the pipe. The results show that the fluid velocity will reduce the natural frequency and affect the modal shapes on the basis of causing static deformation of the pipe. After reaching the critical fluid velocity, the modal combination will occur when the fluid velocity continues to increase. Notably, alterations in pipe length, arc radius, wall thickness, eccentricity and boundary conditions exert diverse effects on the natural frequencies of the pipe. In particular, the arc radius is not involved in the previous study of straight and curved pipe dynamics, so it is analyzed emphatically. Among these variables, the fluid velocity is always a key factor affecting the dynamic characteristics. Finally, experiments and finite element software were used to compare the ANCF method, verifying the effectiveness of the method. Therefore, this paper has developed an effective analytical method to study the flow-induced vibration of complex shaped conveying fluid pipes. [ABSTRACT FROM AUTHOR]

Background: Currently, the existing evidence on the correlation between serum total bilirubin (STB) and Parkinson's disease (PD) is insufficient. The objective of this study was to clarify the relationship between STB levels and PD within the US (United States) population. Methods: A cross-sectional analysis was conducted using data from 25,637 participants in the National Health and Nutrition Examination Survey (NHANES) 1999–2018. Weighted logistic regression, smooth curve fitting, subgroup analysis, and sensitivity analyses were employed to validate the research objectives. Results: Among all eligible subjects, the mean age was 57.11 ± 11.78 years. The prevalence of PD was 1.18 % overall, with 47.86 % in males. After adjusting for multiple variables, the odds ratio [OR] (95 % confidence interval [CI]) for PD associated with STB levels in T2 and T3 were 0.59 (95 % CI = 0.40–0.85, p = 0.006) and 0.67 (95 % CI = 0.45–0.99, p = 0.045), respectively, when compared to STB levels in T1. The analysis using restricted cubic splines (RCS) indicated an L-shaped relationship between STB levels and the prevalence of PD (p for nonlinearity = 0.004), with the lowest risk observed at 10.84 μmol/L. Comparable patterns of association were noted in subgroup analyses. Furthermore, consistent findings were derived from additional sensitivity analyses. Conclusions: Our study findings indicated that the level of STB is significantly negatively correlated with the prevalence of PD. Therefore, more prospective studies need to be designed to prove the causal relationship between them.

BackgroundMental health issues among middle-aged and older adults are gaining increasing attention. Recent studies have shown that relative grip strength is associated with cardiovascular diseases and various cancers, but its relationship with depression remains unclear.MethodsThis cross-sectional study included data from adults aged 50 years and older from the 2011–2014 National Health and Nutrition Examination Survey. Relative grip strength is calculated by dividing the maximum absolute grip strength of both hands by BMI. The Patient Health Questionnaire (PHQ-9) was used to evaluate the depressive outcome. Multivariate logistic regression was performed to assess the association between relative grip strength and depression.ResultsIn this study, a total of 3,639 participants (≥50 years) with a mean age of 64.3 ± 9.3 years were enrolled, of whom 48.9% were male. Compared with individuals with lower relative handgrip strength in Q1 (≤1.64 kg/BMI), the adjusted OR values for relative handgrip strength and depression in Q2 (1.64–2.17 kg/BMI), Q3 (2.17–2.84 kg/BMI), and Q4 (≥2.84 kg/BMI) were 0.69 (95% CI: 0.51, 0.93, p = 0.016), 0.36 (95% CI: 0.24, 0.55, p

The L-shaped partially encased steel–concrete composite (PEC) stub column, composed of profile steel, concrete, and transverse links, tends to occupy less space than the rectangle-shaped PEC column when used as side or corner columns. In this study, an axial compression test involving three L-shaped PEC stub columns was conducted to investigate the influence of critical factors on axial compression performance. The test results indicated that the axial compression capacity can be effectively enhanced with an increase in material strength. Furthermore, finite element (FE) analysis was carried out with parameters such as material strength, steel thickness, transverse link spacing, transverse link diameter, transverse link distribution, and longitudinal rebar diameter. The results revealed that the primary failure modes of L-shaped PEC columns were concrete spalling and local buckling of the flange. Additionally, it was found that the increase in steel strength, steel thickness, and transverse link diameter, as well as the decrease in transverse link spacing, significantly improved the axial compression capacity and concrete confinement effect. However, an increase in concrete strength diminished the concrete confinement effect. Additionally, the accuracy of the axial compression capacity calculation methods in the Eurocode 4 and T/CECS719-2010 specifications for L-shaped PEC stub columns was verified. Finally, a calculation method based on the superposition principle incorporating the concrete confinement effect was proposed, and validated by comparing with experimental and FE results. Overall, this study could provide a theoretical basis for the engineering application of L-shaped PEC columns.

New complex-shaped and thin-walled carbon/carbon (C/C) composites have become the main hot structural material for new hypersonic vehicles because of their superior properties. In the preparation of complex-shaped and thin-walled C/C composites by chemical vapor infiltration (CVI) method, problems such as slow density growth and inhomogeneity of density distribution have been hindering the development of C/C hot structure, in order to solve which, this paper proposes a design method for domain-limited CVI reactors for complex-shaped and thin-walled C/C structure, as well as conducts CVI experiments with the designed domain-limited reactor for a L-shaped and thin-walled C/C structure. A coupled multi-physical field model considering flow, diffusion, and chemical reactions was established, which was verified by comparison with experiments. The effects of diameter of hole, distance of neighboring holes, depth of hole and length of reactor on deposition quality were analyzed by simulation. The results showed that larger diameter of hole and smaller distance of neighboring holes would be more favorable for the accumulation of density of structure and depth of hole has little effect on deposition. The best solution is diameter of hole with 18 mm and distance of neighboring holes with 20 mm. Homogeneity of density can be improved by adjusting the specific length of the reactor. For the fabric sizes given in the study, when the specific length of the preform is 3.4, the deposition rate and homogeneity can reach a good level at the same time. This study is a guideline for optimization the quality of C/C structure during processing.

A new structure of microstrip-based low-pass filter with wide stopband and sharp roll-off is introduced, in this paper. In the proposed topology, resonators with T and modified L Shapes have been used. To improve the suppression factor and relative stopband bandwidth, the second resonator has been added to the first resonator. The designed filter has been fabricated on a 20 mm thickness RO4003 substrate, which has a loss tangent of 0.0021 and a relative dielectric constant equal to 3.38. All parameters including roll of rate, stopband, bandwidth, return loss, insertion loss, and figure of merit have significant coefficients. Simulation has been ran using advanced design system software. The 3dB cutoff frequency is appropriate. The value of the insertion loss parameter is <0.1 dB and the S11 parameter is -22 dB at this point. The stopband is extended from 2.42 up to 24 GHz, which shows an ultra-stopband. The results of the simulation and experiment are almost similar, which indicates a proper performance of the designed structure. [ABSTRACT FROM AUTHOR]

This study presents the mechanical behavior of L-shaped concrete-filled square steel tube (L-CFSST) composite columns under uniaxial eccentric compression. Nine specimens were tested and the effects of eccentricity, steel tube thickness, steel yield strength, and slenderness ratio were investigated regarding failure modes, ultimate load, load-lateral displacement curves, and load-strain curves. Test results showed that, under uniaxial eccentric load, these columns showed favorable mechanical properties and steel tubes showed strong cooperative working performance. There were two types of failure modes for these columns: local buckling of the steel tube or overall bending of the specimen. ABAQUS was used to simulate the loading process and the accuracy of the numerical simulation results was verified by comparing failure characteristics, load-displacement curves, and ultimate bearing capacity with the test results. The N/Nu-M/Mu curves of the columns under uniaxial eccentric load with different parameters were simulated by the finite element method. A simplified formula for predicting the N/Nu-M/Mu relationship was established based on the finite element analysis results, which might be a workable approach for designing L-CFSST composite columns in engineering practice. [ABSTRACT FROM AUTHOR]

A new structure of microstrip-based low-pass filter with wide stopband and sharp roll-off is introduced, in this paper. In the proposed topology, resonators with T and modified L Shapes have been used. To improve the suppression factor and relative stopband bandwidth, the second resonator has been added to the first resonator. The designed filter has been fabricated on a 20 mm thickness RO4003 substrate, which has a loss tangent of 0.0021 and a relative dielectric constant equal to 3.38. All parameters including roll of rate, stopband, bandwidth, return loss, insertion loss, and figure of merit have significant coefficients. Simulation has been ran using advanced design system software. The 3dB cutoff frequency is appropriate. The value of the insertion loss parameter is

In this paper, a monopole UWB broadband antenna is designed, fabricated, and measured for wireless communication networks. The initial radiator model of the proposed antenna has a short-sleeve shape, and to expand the impedance bandwidth, the right and left angles are subtracted symmetrically from the lower half of the radiator. The impedance matching is improved by etching slots in the feed line and adding L-shaped patches symmetrically on both sides of the feed line. The results show that the proposed miniaturized antenna system can cover WiFi 7(2.4–2.484 GHz, 5.15–5.35 GHz, 5.725–5.825 GHz, 5.925–7.125 GHz), 4G LTE (2.3–2.39 GHz, 2.555–2.655 GHz), 5G (4.8–5.0 GHz), X-band (7–12.4 GHz), Ku-band (10.7–14.59 GHz), and C-band uplink bands (5.925–6.425 GHz). Moreover, the antenna is found to be omnidirectional at low frequencies, with a maximum peak gain of 5.43 dBi. The antenna can be used for multi-frequency wireless communication applications. [ABSTRACT FROM AUTHOR]

Migraine is related to brain energy deficiency. Niacin is a required coenzyme in mitochondrial energy metabolism. However, the relationship between dietary niacin and migraines remains uncertain. We aimed to evaluate the relationship between dietary niacin and migraine. This study used cross-sectional data from people over 20 years old who took part in the National Health and Nutrition Examination Survey between 1999 and 2004, collecting details on their severe headaches or migraines, dietary niacin intake, and several other essential variables. There were 10,246 participants, with 20.1% (2064/10,246) who experienced migraines. Compared with individuals with lower niacin consumption Q1 (≤12.3 mg/day), the adjusted OR values for dietary niacin intake and migraine in Q2 (12.4–18.3 mg/day), Q3 (18.4–26.2 mg/day), and Q4 (≥26.3 mg/day) were 0.83 (95% CI: 0.72–0.97, p = 0.019), 0.74 (95% CI: 0.63–0.87, p < 0.001), and 0.72 (95% CI: 0.58–0.88, p = 0.001), respectively. The association between dietary niacin intake and migraine exhibited an L-shaped curve (nonlinear, p = 0.011). The OR of developing migraine was 0.975 (95% CI: 0.956–0.994, p = 0.011) in participants with niacin intake < 21.0 mg/day. The link between dietary niacin intake and migraine in US adults is L-shaped, with an inflection point of roughly 21.0 mg/day. [ABSTRACT FROM AUTHOR]

In this paper, a prefabricated special-shaped concrete-filled steel tube (CFST) with rectangular multi-cell column has been subjected to low cyclic reversed loading experiment and finite element (FE) parameter analysis. A total of three full-scale L-shaped specimens were tested under constant axial compression load and transverse cyclic load. The main variable in the experiment was the direction of loading. The results show that the failure mode of the special-shaped column specimen is compression-bending failure. Within 300 mm of the bottom of the column, the steel tube bulges or even cracks, the concrete powder fells and fails to exit the work. Among them, the L-135° specimen has the highest peak bearing capacity while the L-0° specimen has better ductility. The main variables of FE parametric analysis are axial compression ratio, concrete grade, steel tube thickness and loading angle. The analysis results show that the lower axial compression ratio and higher concrete grade are conducive to the improvement of bearing capacity. As the thickness of the steel tube increases, the peak bearing capacity and displacement of the specimen increases but the ductility decreases. The special-shaped column model has better seismic behavior when loaded along various loading angles. The peak bearing capacity of the special-shaped column specimen loaded at 135° is consistent with the test results and compared with the L-45° specimen, its bearing capacity is increased by up to 62.04%, which has better comprehensive seismic behavior. [ABSTRACT FROM AUTHOR]

Based on the L-shaped diagram, this paper discusses the mechanism of architectural form generation, through the method of logical deduction and type induction. First, starting from graphic characteristics, the L-shaped diagram is divided into two types: "the linear L-shaped" and "the centroidal L-shaped". Secondly, from the overall and local levels, it analyzes the spatial operation method of L-shaped volume. Finally, from the three levels of unit space, linear space and topological space, it discusses the operation methods of constructing continuous and dynamic space by using L-shaped diagram. The research results can deepen the understanding of spatial construction based on geometric illustration and offer some insights for exploring the internal logic and external presentation of architectural design. [ABSTRACT FROM AUTHOR]

Background: Chronic kidney disease (CKD), which has become a global public health issue, is associated with mitochondrial dysfunction. Niacin is a necessary coenzyme for mitochondrial energy metabolism. However, the association between dietary niacin intake and CKD remains uncertain. This study aimed to investigate the association between dietary niacin intake and CKD in American adults., Methods: This is a cross-sectional study. 25,608 individuals aged ≥20 years from the National Health and Nutrition Examination Survey from 2007 to 2018 were involved.Dietary niacin intake was estimated based on 24-hour dietary recalls conducted by trained personnel. CKD was determined by an estimated glomerular filtration rate (eGFR) (<60 ml/min/1.73 m 2 ) or a urinary albumin-to-creatinine ratio (ACR) (≥30mg/g). The association between dietary niacin intake and CKD was investigated using multivariable logistic regression analysis., Results: Of 25,608 participants, 17.14% (4388/25,608) had CKD. Compared to individuals with lower niacin intake (quartile [Q]1, ≤15.30 mg/day), those with higher niacin intake in Q2 (15.31-22.07 mg/day), Q3 (22.08-31.09 mg/day), and Q4 (≥31.10 mg/day) exhibited adjusted odds ratios for CKD of 0.89 (95% confidence interval [CI]:0.81-0.99, p  = 0.024), 0.83 (95% CI:0.75-0 .92, p  < 0 .001), and 0.83 (95% CI:0.75-0.93, p  = 0.001) respectively. The relationship between dietary niacin intake and CKD among U.S. adults follows an L-shaped pattern, with an inflection point at approximately 28.04 mg/day., Conclusions: These results suggest an L-shaped association between dietary niacin intake and CKD. Individuals with low dietary niacin intake levels should be alert to the risk of CKD.

This work presents the performance of a Dual-band patch antenna with L-shaped slot for biomedical applications. The antenna works at 2.4 GHz and 3.33 GHz. A semi-flexible substrate material which is “Taconic TLX (tm)” with a relative dielectric constant, ℇr of 2.55, loss tangent, tan δ of 0.0019 and thickness, h of 0.7 mm has been proposed to be the isolant element of the antenna. The size of the antenna is 60 x 55 mm². The slots in the rectangular radiating patch were introduced to produce the resonant frequencies of 2.4GHz and 3.33GHz. The simulations of the microstrip patch antenna shows the reflection coefficient, S11 of -31.67 dB and -20.25 dB at 2.4 GHz and 3.27 GHz respectively. The proposed antenna shows a peak gain of 5.01 dB at 2.4 GHz. The results were obtained using HFSS (high frequency structured simulator) software.

Background: Currently, the existing evidence on the correlation between serum total bilirubin (STB) and Parkinson's disease (PD) is insufficient. The objective of this study was to clarify the relationship between STB levels and PD within the US (United States) population., Methods: A cross-sectional analysis was conducted using data from 25,637 participants in the National Health and Nutrition Examination Survey (NHANES) 1999-2018. Weighted logistic regression, smooth curve fitting, subgroup analysis, and sensitivity analyses were employed to validate the research objectives., Results: Among all eligible subjects, the mean age was 57.11 ± 11.78 years. The prevalence of PD was 1.18 % overall, with 47.86 % in males. After adjusting for multiple variables, the odds ratio [OR] (95 % confidence interval [CI]) for PD associated with STB levels in T2 and T3 were 0.59 (95 % CI = 0.40-0.85, p  = 0.006) and 0.67 (95 % CI = 0.45-0.99, p  = 0.045), respectively, when compared to STB levels in T1. The analysis using restricted cubic splines (RCS) indicated an L-shaped relationship between STB levels and the prevalence of PD ( p for nonlinearity = 0.004), with the lowest risk observed at 10.84 μmol/L. Comparable patterns of association were noted in subgroup analyses. Furthermore, consistent findings were derived from additional sensitivity analyses., Conclusions: Our study findings indicated that the level of STB is significantly negatively correlated with the prevalence of PD. Therefore, more prospective studies need to be designed to prove the causal relationship between them., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors. Published by Elsevier Ltd.)

Background: Mental health issues among middle-aged and older adults are gaining increasing attention. Recent studies have shown that relative grip strength is associated with cardiovascular diseases and various cancers, but its relationship with depression remains unclear., Methods: This cross-sectional study included data from adults aged 50 years and older from the 2011-2014 National Health and Nutrition Examination Survey. Relative grip strength is calculated by dividing the maximum absolute grip strength of both hands by BMI. The Patient Health Questionnaire (PHQ-9) was used to evaluate the depressive outcome. Multivariate logistic regression was performed to assess the association between relative grip strength and depression., Results: In this study, a total of 3,639 participants (≥50 years) with a mean age of 64.3 ± 9.3 years were enrolled, of whom 48.9% were male. Compared with individuals with lower relative handgrip strength in Q1 (≤1.64 kg/BMI), the adjusted OR values for relative handgrip strength and depression in Q2 (1.64-2.17 kg/BMI), Q3 (2.17-2.84 kg/BMI), and Q4 (≥2.84 kg/BMI) were 0.69 (95% CI: 0.51, 0.93, p  = 0.016), 0.36 (95% CI: 0.24, 0.55, p  < 0.001), and 0.32 (95% CI: 0.20, 0.51, p  < 0.001), respectively. The relationship between relative grip strength and depression presented an L-shaped curve (nonlinear, p  = 0.006), with an inflection point of roughly 2.98 kg/BMI. Among participants with relative grip strength < 2.98 kg/BMI, the OR of incident depression was 0.41 (95% CI: 0.30-0.55, p  < 0.001)., Conclusion: Our findings indicated that relative grip strength was inversely associated with incident depression and demonstrated an L-shaped relationship among U.S. middle-aged and older adults. Relative grip strength could be the indicator for future screening of mental health., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Sun and Liu.)

In this paper, a monopole UWB broadband antenna is designed, fabricated, and measured for wireless communication networks. The initial radiator model of the proposed antenna has a short-sleeve shape, and to expand the impedance bandwidth, the right and left angles are subtracted symmetrically from the lower half of the radiator. The impedance matching is improved by etching slots in the feed line and adding L-shaped patches symmetrically on both sides of the feed line. The results show that the proposed miniaturized antenna system can cover WiFi 7(2.4–2.484 GHz, 5.15–5.35 GHz, 5.725–5.825 GHz, 5.925–7.125 GHz), 4G LTE (2.3–2.39 GHz, 2.555–2.655 GHz), 5G (4.8–5.0 GHz), X-band (7–12.4 GHz), Ku-band (10.7–14.59 GHz), and C-band uplink bands (5.925–6.425 GHz). Moreover, the antenna is found to be omnidirectional at low frequencies, with a maximum peak gain of 5.43 dBi. The antenna can be used for multi-frequency wireless communication applications.

In this paper, we propose a Si/Ge heterojunction TFET with two in-line tunneling junctions to enhance the low on-state current of TFETs, which is their main drawback. The device, named GL-TFET, has an L-shaped architecture with two bottom and side Ge-source regions and an S-shaped gate to enhance the electric field in the device channel. Tunneling of electrons happens in two vertical and horizontal directions from bottom source and side source, respectively, both perpendicular to the gate, and leads to a remarkably high on-state current of 569µA/µm at 0.5 V operating voltage, which is a new record. Our TFET shows sub-60 mV/dec point subthreshold swing over 10 decades of drain current and average subthreshold swing of 11.6 mV/dec, while owing to its geometrical design, no ambipolar conduction is observed in the transfer characteristics. In addition to the switching performance of the proposed device, the analog and RF characteristics are also investigated and a cut-off frequency of 148 GHz is recorded. The performance evaluation is carried out using a calibrated numerical device simulator. [ABSTRACT FROM AUTHOR]

Migraine is related to brain energy deficiency. Niacin is a required coenzyme in mitochondrial energy metabolism. However, the relationship between dietary niacin and migraines remains uncertain. We aimed to evaluate the relationship between dietary niacin and migraine. This study used cross-sectional data from people over 20 years old who took part in the National Health and Nutrition Examination Survey between 1999 and 2004, collecting details on their severe headaches or migraines, dietary niacin intake, and several other essential variables. There were 10,246 participants, with 20.1% (2064/10,246) who experienced migraines. Compared with individuals with lower niacin consumption Q1 (≤12.3 mg/day), the adjusted OR values for dietary niacin intake and migraine in Q2 (12.4–18.3 mg/day), Q3 (18.4–26.2 mg/day), and Q4 (≥26.3 mg/day) were 0.83 (95% CI: 0.72–0.97, p = 0.019), 0.74 (95% CI: 0.63–0.87, p < 0.001), and 0.72 (95% CI: 0.58–0.88, p = 0.001), respectively. The association between dietary niacin intake and migraine exhibited an L-shaped curve (nonlinear, p = 0.011). The OR of developing migraine was 0.975 (95% CI: 0.956–0.994, p = 0.011) in participants with niacin intake < 21.0 mg/day. The link between dietary niacin intake and migraine in US adults is L-shaped, with an inflection point of roughly 21.0 mg/day.

The mechanical behavior of L-shaped steel reinforced concrete (SRC) columns after exposure to high temperatures is investigated by conducting experiments on eight column specimens. The specimens are first heated to a target temperature and are loaded to failure after cooling down to room temperature. The effect of heating duration, loading eccentricities, and loading angles on the temperature distribution, failure mode and residual bearing capacity of the columns is studied. The test results show that L-shaped SRC columns under axial and eccentric loading have a post-high temperature shear and bending failure mode, respectively. The residual bearing capacity of the specimens decreases significantly (up to 1/3) compared to that at room temperature. The residual bearing capacity of L-shaped SRC columns is governed by loading eccentricities, and an eccentricity of 80 mm (0.36) leads to a reduction in residual capacity by 47% of its ambient value. The loading angle has an obvious effect on the damage range of L-shaped SRC columns. A formula for calculating the residual bearing capacity of L-shaped SRC columns under biaxially eccentric compression is proposed and validated against test results. [ABSTRACT FROM AUTHOR]

An innovative design of a circular polarization antenna for wireless power transmission is described. The suggested antenna is simply constructed, which consists of a square radiating patch having a slotted center with feeding via a probe and an L-shaped ground plane. The application of this L-shaped ground allows a short connection of the probe power supply to the square patch while retaining a certain elevation from the ground plane to the square patch while using an air layer substrate, thereby allows a proper adaptation of the impedance and an improvement of the bandwidth. The purpose of utilizing the slot in the center of the square patch is to create a circular polarization with an axial ratio value of under 3dB. By means of a through-hole through the vertical L-shaped ground plane, the patch radiating can be readily excited with a probe feed pointing into the same plane as the patch. This approach allows to further improve the bandwidth of the circular polarization. In this way, the CP bandwidth of the proposed antenna is significantly extended by about 10% and a good impedance matching over a wide bandwidth is obtained. The features of the proposed design are investigated and optimized using a 3D electromagnetic (EM) solver. It was found that the proposed antenna covers a broad band of 425MHz, has a 3 dB axial ratio CP bandwidth of approx. 85% of the resonant band, and a gain level of 7.4 dBi or more in the bandwidth of the resonant band. Besides the low cost of the proposed antenna arising from its simplest structure, the resulting performance leads the antenna to be a strong candidate among circularly polarized, single element, and single feed patch antennas.

Concrete-filled steel tubular (CFST) members have been widely used in industrial structures and high-rise residential buildings. The multi-cell composite L-shaped concrete-filled steel tubular (ML-CFST) cross-section, as an innovative, special-shaped structural arrangement, may solve the issue of normal CFST members protruding from walls and result in more usable interior space. Currently, no design rules are available for the application of ML-CFST members. One of the primary objectives of the present study is to develop recommendations in line with the unified theory to evaluate the bending moment resistance of ML-CFST beams. According to the unified theory, the bending moment resistance of an ML-CFST beam is related to the compressive strength (fsc) and the flexural strength index (γm) of a composite section, in which the accuracy of γm and fsc are affected by a confinement effect factor (ξ). Nevertheless, the original expression of ξ is not suitable for ML-CFST sections, since the appreciable effect of the irregular shape on confinement is neglected. Considering the cross-sectional geometry and boundary conditions of the cells, an equivalent shape factor to modify the confinement effect was proposed in this study through dividing the infill concrete into highly confined areas and less confined areas. An adequate formula to calculate the fsc and an approximate expression of γm for the ML-CFST sections was then developed. Furthermore, four-point bending tests on eight specimens were carried out to investigate the flexural performance of the ML-CFST beams. Lastly, the proposed formulas were assessed against experimental and numerical results. The comparisons show that the proposed unified theory-based approach produced accurate and generally conservative results for the ML-CFST beams studied.

This study proposes a method for locating and evaluating plate damage based on the determination of natural frequencies and modal forms of defective plates using an optimization approach. For simulations finite element method is used, form SolidWorks software. The efficiency of the presented method is explored by a comparison of the results obtained for several case studies of L-shaped plates assemblies having different defects and positions on plates. The results obtained confirm the applicability and effectiveness of the suggested method for solving the problems of localizing and quantifying defects on plates.

One method of identifying defects is to directly solve the optimization problem to obtain a set of parameters for locating and quantifying damages in the structure. Numeric or digital simulation uses computerized modelling and analysis to test static or dynamic behaviour of components subjected to stress,under different operating conditions.This type of analysis involves, however, the assimilation of operating modes with a specialized assisted design program as well as finite element simulation and analysis programs.Method used in present paper for analysing defects on components such L-shaped platens assembly is one of finite element, by means of SolidWork software. The purpose is to obtain Eigen modes ofL-shaped platens assembly embedded on a surface in order to use the results for further analysis in technical applications.

In the last century, many infectious diseases have been completely eradicated or significantly reduced because of childhood vaccinations. Ample evidence suggests that low vaccination coverage in developing countries is caused by vaccine stockout and high rates of vaccine wastage. Wastage occurs when a vaccine vial is physically damaged or exposed to extreme temperatures, or when doses from an open vial are discarded after their safe-use time expires. The latter is referred to as open vial wastage (OVW). Clinics can use single-dose vials to reduce OVW; however, such an approach is more expensive than using multi-dose vials. The focus of this research is to develop new policies that support vaccine administration and inventory replenishment. These policies are expected to reduce OVW, reduce the cost of vaccinations, and improve vaccination coverage levels in developing countries. This paper proposes a two-stage stochastic programming model that identifies an optimal combination of differently sized vaccine vials and the corresponding decisions that clinics make about opening vials in the face of uncertain patient arrivals. This work develops a case study with data gathered from Bangladesh. Experimental results indicate that using a combination of vials of different sizes reduces OVW, as opposed to the current practice of using single-sized multi-dose vials. Experimental results also point to simple and economic vaccine administration policies that health care administrators can use to minimize OVW. The model is solved using an extension of the stochastic Benders decomposition algorithm, the L-shaped method (LS). This algorithm uses Gomory mixed integer and mixed-integer rounding cuts to address the problem's non-convexity. Computational results reveal that the solution approach presented here outperforms the standard LS method. [ABSTRACT FROM AUTHOR]

Steel-concrete composite frames have been widely used in high-rise buildings. To improve the utilization efficiency of the indoor area, irregular-shaped concrete-filled steel tubular (CFST) columns were proposed for an alternative of the traditional rectangular CFST columns. In this paper, the L-shaped multi-cellular CFST (LM-CFST) frame was proposed, consisting of LM-CFST columns and H-shaped steel beams. Firstly, four LM-CFST frames were tested under combined axial compression and cyclic lateral loads. The local buckling was observed at both the top and bottom ends of the column, and fracture of steel occurred when the drift ratio was large. The hysteresis curves were spindle-shaped with the ductility indexes of 2.61–3.24. Then, a refined finite element model was established and validated against the test results. A parametric analysis was conducted to study the effect of axial compression ratio, web cell length, concrete strength and steel tube thickness on the seismic performance of LM-CFST frames. It was found that the axial compression ratio could affect the seismic performance of LM-CFST frames significantly, while the concrete strength had little effect. Finally, the compression-bending capacities obtained from the sectional analysis method specified in EC4 were compared with those obtained from tests. It was found that this method could predict the compression-bending capacity of the LM-CFST frame under combined axial compression and cyclic lateral loads with reasonable discrepancies. • Four 1/2 scale LM-CFST frames were tested under combined axial compression and cyclic loads. • The failure modes and hysteretic responses were discussed. • A validated FE model was established for further investigation. • A parametric analysis was conducted to investigate the influence on the seismic performance of the LM-CFST frames. • A simplified method was proposed to evaluate the compression-bending capacity of the LM-CFST frame. [ABSTRACT FROM AUTHOR]

Considerable progress has been made on the research of non-rectangular reinforced concrete (RC) squat walls over the past decades. However, the experimental data of L-shaped RC squat walls remain limited, especially for their seismic behaviors under non-principal bending actions. This paper presents an experimental and numerical investigation on L-shaped RC squat structural walls with an emphasis on how varying the directions of lateral cyclic loading influences the seismic responses of these walls. Four L-shaped specimens are tested under lateral cyclic displacements and low levels of axial compression The variables are axial loads and lateral loading directions. The performance of specimens is discussed in terms of cracking patterns, failure mechanisms, hysteretic responses, deformation components and strain profiles. Furthermore, three-dimensional finite element models are developed to supplement the experimental results. The direction of lateral loading is found to have a significant effect on the peak shear strength of L-shaped RC squat walls. [ABSTRACT FROM AUTHOR]

Currently, the frame structures with special-shaped concrete-filled steel tubular columns have been widely used in super high-rise buildings. Those structural members can be used to improve architectural space. To investigate the seismic behavior of spatial composite frames that were constructed by connecting steel beams to L-shaped concrete-filled steel tubular (CFST) columns, a finite element analysis (FEA) model using commercial finite element software ABAQUS was proposed to simulate the behavior of the composite spatial frames under a static axial load on columns and a fully-reversed lateral cyclic load applied to frames in this paper. Several nonlinear factors, including geometry and material properties, were taken into account in this FEA model. Four spatial specimens were designed, and the corresponding experiments were conducted to verify the proposed FEA model. Each testing specimen was two-story structure consisting of eight single span steel beams and four L-shaped CFST columns. The test results showed that the proposed FEA model in this paper could evaluate the behavior of the composite spatial frames accurately. Based on the results of the nonlinear analysis, the stress developing progress of columns is investigated. The load transferring mechanism and failure mechanism are also determined. The results are discussed and conclusions about the behavior of those spatial frame structures are presented. [ABSTRACT FROM AUTHOR]

One method of identifying defects is to directly solve the optimization problem to obtain a set of parameters for locating and quantifying damages in the structure. Numeric or digital simulation uses computerized modelling and analysis to test static or dynamic behaviour of components subjected to stress, under different operating conditions. This type of analysis involves, however, the assimilation of operating modes with a specialized assisted design program as well as finite element simulation and analysis programs. Method used in present paper for analysing defects on components such Lshaped platens assembly is one of finite element, by means of SolidWork software. The purpose is to obtain Eigen modes of L-shaped platens assembly embedded on a surface in order to use the results for further analysis in technical applications. [ABSTRACT FROM AUTHOR]

Curved composite components are widely used in engineering applications, such as aircraft wing spars, and subjected to complex 3D loadings. The most critical failure mechanisms of the curved parts are intra-laminar matrix cracking and inter-laminar delamination. A computational approach has been proposed to explicitly model the intra-laminar matrix cracking and inter-laminar delamination in L-shaped cross-ply laminates with cohesive elements. Zero-thickness cohesive elements with a mixed-mode traction-separation damage law are inserted in each 90° lamina to predict matrix cracking and also inserted between neighboring plies to account for inter-laminar delamination. Two laminate stacking sequences with distinguished features of isolating different modes of failure have been investigated. The simulation results confirmed that stacking sequence [0/90 3 /0 2 /90 3 /0] s trends to highlight the matrix failure mode, while the stacking sequence [0 3 /90/0 3 /90/0/90] s trends to highlight the delamination mode. The kinking cracking across 90° plies accompanying the delamination-dominated failure mode during the subsequent crack propagation can be also predicted. The computational results have been compared with the corresponding experimental observations reported in the literature. The good agreement with the reported experimental results verified the capability and effectiveness of computational modelling approach. [ABSTRACT FROM AUTHOR]

Summary: Precast shear walls, as an environmentally friendly building system, have been vigorously developed in China. There are many vertical and horizontal joints on precast reinforced concrete shear wall system, which certainly have a significant effect on seismic performance of structures. In this paper, 3 L‐shaped precast reinforced concrete shear walls that were assembled by 2 precast parts through a middle cast‐in‐situ joint and a compared 1 completely cast‐in‐situ were tested under low frequency cyclic loading to investigate their seismic behaviors. The vertical distributed reinforcements in the three precast specimens were equivalently spliced by grouting sleeves arranged along the center line of the wall, and the horizontal reinforcements were directly anchored in cast‐in‐situ joints. The experimental results, including failure mode, yielding load and displacement, skeleton curve, energy dissipation, stiffness degradation, ductility, and so forth were presented in the paper. The results show that the precast specimens have similar bearing capacity whereas much better deformation capacity and ductility compared to the cast‐in‐situ specimen. Additionally, the experimental results of ultimate shear capacity of specimens were also compared with that of the calculation results. These results indicate that the tested precast shear walls have good and reliable seismic performance and can be used as a structural member in engineering projects. [ABSTRACT FROM AUTHOR]

This study proposes a method for locating and evaluating plate damage based on the determination of natural frequencies and modal forms of defective plates using an optimization approach. For simulations finite element method is used, form SolidWorks software. The efficiency of the presented method is explored by a comparison of the results obtained for several case studies of L-shaped plates assemblies having different defects and positions on plates. The results obtained confirm the applicability and effectiveness of the suggested method for solving the problems of localizing and quantifying defects on plates. [ABSTRACT FROM AUTHOR]

The stacking sequence effect of narrow L-shaped laminates on the fracture mode was studied. Two laminate stacking sequences were designed to analyze different fracture modes. The sequence layup J, i.e., [0/904/02/902/02/902/02/90]s trends to highlight the matrix fracture mode, whereas the stacking sequence layup I, i.e., [04/90/03/90/02/902/02/90]s tends to highlight the delamination mode. Load-deflection curves and fracture modes for these stacking sequences under a four-point bending loads were recorded and compared with the plane-strain empirical formula and experimental results. The results show that the stacking sequence has a significant effect on the initial fracture mode of narrow L-shaped laminar composites. Layup J shows matrix-dominant initial fracture due to the weak resistance of inner 90° plies to tangential tensile stresses, whereas layup I experiences delamination-dominant initial failure. The edge effect has a great influence on the fracture mode of layup J-like specimens, whereas it is very weak for layup I-like ones. The stacking sequence also influences the carrying capacity; a maximum fracture load of layup J is apparently lower than that of layup I, by about 23%. [ABSTRACT FROM AUTHOR]

We study a last mile distribution network design problem for situations where there exist local distribution centers (LDCs) with prepositioned supplies. Given the information on the existing pre-disaster relief network, the problem determines the locations and capacities of LDCs and points of distribution in the relief network, while capturing the uncertain aspects of the post-disaster environment. We introduce a new accessibility metric and develop a two-stage stochastic programming model that would allow more accessible and equitable distribution of relief supplies. Since solving the proposed stochastic optimization model is computationally challenging, we employ a scenario decomposition-based branch-and-cut algorithm. We perform a computational study-based on the real-world data from the 2011 Van earthquake in Turkey-to provide insights about the model and demonstrate the effectiveness of the solution method. [ABSTRACT FROM AUTHOR]

The production of biofuels using second-generation feedstocks has been recognized as an important alternative source of sustainable energy and its demand is expected to increase due to regulations such as the Renewable Fuel Standard. However, the pathway to biofuel industry maturity faces unique, unaddressed challenges. To address this challenges, this paper presents an optimization model which quantifies and controls the impact of biomass quality variability on supply chain related decisions and technology selection. We propose a two-stage stochastic programming model and associated efficient solution procedures for solving large-scale problems to (1) better represent the random nature of the biomass quality (defined by moisture and ash contents) in supply chain modeling, and (2) assess the impact of these uncertainties on the supply chain design and planning. The proposed model is then applied to a case study in the state of Tennessee. Results show that high moisture and ash contents negatively impact the unit delivery cost since poor biomass quality requires the addition of quality control activities. Experimental results indicate that supply chain cost could increase as much as 27%–31% when biomass quality is poor. We assess the impact of the biomass quality on the topological supply chain. Our case study indicates that biomass quality impacts supply chain costs; thus, it is important to consider the impact of biomass quality in supply chain design and management decisions. [ABSTRACT FROM AUTHOR]

Currently, the frame structures with special-shaped concrete-filled steel tubular columns have been widely used in super high-rise buildings. Those structural members can be used to improve architectural space. To investigate the seismic behavior of spatial composite frames that were constructed by connecting steel beams to L-shaped concrete-filled steel tubular (CFST) columns, a finite element analysis (FEA) model using commercial finite element software ABAQUS was proposed to simulate the behavior of the composite spatial frames under a static axial load on columns and a fully-reversed lateral cyclic load applied to frames in this paper. Several nonlinear factors, including geometry and material properties, were taken into account in this FEA model. Four spatial specimens were designed, and the corresponding experiments were conducted to verify the proposed FEA model. Each testing specimen was two-story structure consisting of eight single span steel beams and four L-shaped CFST columns. The test results showed that the proposed FEA model in this paper could evaluate the behavior of the composite spatial frames accurately. Based on the results of the nonlinear analysis, the stress developing progress of columns is investigated. The load transferring mechanism and failure mechanism are also determined. The results are discussed and conclusions about the behavior of those spatial frame structures are presented.

Trees exploit intriguing mechanisms such as multimodal frequency distributions and nonlinearities to distribute and dampen the aerodynamically-induced vibration energies to which they are subjected. In dynamical systems, these mechanisms are comparable to internal resonance phenomena. In recent years, researchers have harnessed strong nonlinearities, including internal resonance, to induce energetic dynamics that enhance performance of vibration energy harvesting systems. For trees, the internal resonance-like dynamics are evidently useful to dampen swaying motions in spite of the high variation associated with excitation and structural parameters. Yet for dynamic systems, studies show narrow operating regimes which exhibit internal resonance-based behaviors; this additionally suggests that the energetic dynamics may be susceptible to deactivation if stochastic inputs corrupt ideal excitation properties. To address these issues and to investigate whether the underlying motivation of exploiting internal resonance-induced saturation dynamics is truly justified, this research evaluates the opportunities enabled by exploiting nonlinear, multimodal motions in an L-shaped energy harvester platform. The system dynamics are probed analytically, numerically, and experimentally for comprehensive insights on the versatility of internal resonance-based behaviors for energy harvesting. It is found that although activating the high amplitude nonlinear dynamics to enhance power generation is robust to significant additive noise in the harmonic excitations, parameter sensitivities may pose practical challenges in application. Discussion is provided on means to address such concerns and on future strategies that may favorably exploit nonlinearity and multimodal dynamics for robust energy harvesting performance. [ABSTRACT FROM AUTHOR]