Heavy Weight Research Articles

COMPARISON OF ROLLER COMPACTED CONCRETE PAVEMENT RESPONSES TO STATIC AND DYNAMIC LOADS

The objective of the study was to compare Roller Compacted Concrete (RCC) pavements responses to static and dynamic loads. Two sets of non-destructive load testing were performed on RCC pavements. The first set used static loading and dynamic loading was utilized for the second. Static loading was provided by front wheels of a Letro-Porter (front loader) and a Heavy Weight Deflectometer (HWD) was used for dynamic loading. A back-calculation procedure for estimating concrete pavement parameters is also presented. The Roller Compacted Concrete pavements were located at Moran Terminal, Boston, Massachusetts. The pavement consisted of a RCC layer of 38 cm (15 in.), a 23-cm (9-in.) gravel subbase and a compacted subgrade. The RCC layer was constructed in three lifts from bottom to top of 14, 14, and 10 cm (5.5, 5.5 and 4 in.). Four slabs were selected for testing. Strains and deflections were measured for static loading tests. A Benkelman beam was used for measuring the static load induced deflections. Deflection basins were determined during HWD tests. Load transfer efficiency at cracks and construction joints was also measured for both tests. The back-calculation procedure has been demonstrated to be satisfactory in estimating in situ pavement material properties. Using estimated RCC elastic moduli and estimated moduli of subgrade reaction, the stresses in the slabs caused by the static loads were computed by the finite element computer program JSLAB and compared to field measured stresses. It was found that the computed stresses were always greater than the measured values. A factor of safety of about 4% can be expected when HWD deflection data are used in place of static vehicle test data in rigid pavement analysis and design.

Design and Development of Green Trash Compactor for Recyclable Waste Management

A trash compactor is a mechanical device invented to reduce the volume of trash, making it suitable for use in various scenes such as domestic, public, and industries. Utilizing this kind of machine provides significant benefits in the waste accumulation system, as it allows for more efficient waste management by compacting the trash, enabling larger quantities to be collected at once. In this study, a Green Trash Compactor is designed and developed as an innovative semi-automated machine to efficiently reduce the size and volume of recyclable materials such as plastics, paper cups, and PET bottles. The project focuses on optimizing the sensor layout to minimize the impact during the compaction process, thereby reducing the requirement for heavy load cells or weight sensors. The working output is achieved by recording different input commands through buttons, where the system employs load cells to identify the detected force, and the microcontroller makes corresponding decisions. The results indicated that the Green Trash Compactor successfully operated with its mechanical and programmed codes, demonstrating impressive volume reduction during the compaction process. This substantial reduction in volume contributes to lowering transportation costs for the trash, making the compactor a highly efficient waste management solution.

Comparative Life Cycle Assessment of Traditional and Modern Materials in Heritage Building Restoration: A Case Study from Ushaiger Village

This paper presents a comparative life cycle assessment (LCA) of the traditional and modern materials used in heritage building restoration, focusing on mud, limestone, decorative plaster, blended hydraulic cement, and ready-mix concrete. The analysis examines key environmental impact categories, including global warming potential (GWP), ozone depletion potential (ODP), acidification potential (AP), eutrophication potential (EP), and water use across multiple life cycle stages. The results reveal that mud and limestone, while having lower initial environmental impacts in production, contribute significantly to ODP and GWP during transportation due to their heavy weight. Modern materials like blended hydraulic cement and ready-mix concrete exhibit the highest overall environmental impacts, particularly in GWP, AP, and water use, due to their energy-intensive production processes. Decorative plaster, while lower in initial impacts, gains higher environmental burdens over time due to its frequent replacement. This study highlights the need to optimize transportation and improve recycling practices for traditional materials, while also encouraging the exploration of alternative materials for reducing the environmental footprint of heritage restoration.

Profiling of agronomic traits and folic acid in five dessert bananas (Musa spp.)

Many varieties of Musa spp. have been used as edible fruits around the world. Bananas belong to the genus Musa, whose fruits contain high calories and nutritional values. There is little data on agronomic traits and folic acid (FA) concentrations of different types of dessert bananas in Vietnam. This study aimed to determine such information in the fruits of five banana varieties, including Cau, Xiem, Gia Huong, Com, and Dole. Agronomic characteristics were considered, including fruit size and weight, peel colour and pulp firmness, while FA concentrations were quantified by high-performance liquid chromatography. The results showed significant differences among agronomic values and FA contents. Dole had the heaviest weight (175.48 g), followed by Xiem (123.71 g), Gia Huong (121.77 g), Com (103.12 g) and Cau (52.07 g). The size (length × width) of 5 cultivars has significant differences, including Dole (16.22 × 4.17 cm), Xiem (11.78 × 4.44 cm), Gia Huong (15.44 × 4.22 cm), Com (11.59 × 3.88 cm) and Cau (9.00 × 3.79 cm). For the colour results, most banana cultivars had yellow peels, except Gia Huong which remained green colour at ripening stages (b/a<0). The pulp firmness is expressed with the hardest value from Xiem (0.59 N), then Dole (0.36 N), Com (0.32 N), Cau and Gia Huong (0.29 N). The FA concentrations ranged 3-12 μg /100 g fresh weight. The cultivar Cau had the highest level of FA per 100 g fresh weight (12.04 μg), followed by Gia Huong (8.76 μg), Dole (6.00 μg), Xiem (4.62 μg), and Com (3.14 μg). The FA contents were positively correlated with the colour brightness L, performed by Pearson value, with r = 0.755 (p<0.001). On the other hand, an inverse correlation was found between FA concentration and the fruit weight (r = -0.542, p<0.001) and the pulp firmness (r = -0.337, p<0.05). In conclusion on 5 varieties of dessert bananas, measured values of agronomic traits and FA have been recorded, and Pearson analysis shows a positive relation between FA and colour brightness and a negative one between FA and fruit weight/firmness.

Experimental Study on the Mechanical Properties of Reactive Powder Concrete Ultra-Thin Precast Slab for Bridge I-Beam Joints

In the domain of bridge I-beam joint construction, conventional approaches such as cast-in-place concrete with suspended formwork and ordinary reinforced concrete precast slabs entail numerous limitations. The former features complex procedures, elevated costs, and significant safety risks, while the latter is hindered by the heavy weight of precast slabs, which causes difficulties in transportation and hoisting, inconvenient installation, and high costs. Reactive powder concrete ultra-thin precast slab (RPCUPS) is regarded as a potential solution due to its superior properties. Nevertheless, at present, there is an acute paucity of experience and research regarding the application of RPCUPS in bridge I-beam joints, particularly on a large scale. In a certain actual engineering project, a scheme was proposed to employ RPCUPS with a mere thickness of 20 mm in the bridge I-beam joints. In this scheme, the quantity of slabs is substantial, amounting to over 600,000. This constitutes the research gap and impetus of this study, with the aim of filling the existing knowledge void and providing technical support for engineering endeavors. This research carried out an extensive experimental test to systematically investigate the mechanical properties and safety of RPCUPS. Firstly, the material performance experiments were conducted to determine the manufacturing process of RPCUPS that meets the performance requirements. Subsequently, loading experiments on specimens under multiple working conditions were performed to disclose the cracking load and ultimate load of the two main types of RPCUPS and to analyze the influences of fiber type, mixing type, steel mesh, and slab thickness on the mechanical properties of RPCUPS (keeps the same volume rate of steel in a slab). Key findings encompass the outstanding mechanical properties and high safety factors of RPCUPS under diverse working conditions. Finally, in light of the actual construction environment, safety verification of temporary loading during actual construction was executed to furnish solid technical support for the practical engineering application of RPCUPS. The experimental results indicate that RPCUPS has been successfully applied on a large scale in actual engineering projects, not only without augmenting the cost but also significantly reducing the construction period by approximately five months, conspicuously enhancing the construction efficiency. These discoveries not only validate the feasibility of RPCUPS in bridge I-beam joint construction but also offer valuable references and guidance for similar future projects.

FEM for improvement of damage prediction of airfield flexible pavements on soft and stiff subgrade under various heavy load configurations of landing gear of new generation aircraft

Abstract This study establishes the state-of-the-art requirements verification process applied to compute the damage of flexible airfield pavement from new French rational method. Flexible pavement structures with platforms A, B, C, and D, recommended by International Civil Aviation Organization (ICAO), were modelled under static loading of bogies from heavy weight aircrafts A340, B777, and A380 using Cast3M 3D finite element modelling. From the results of these computations, it appears that these structures A, B, C, and D recommended by ICAO are not equivalent from the point of view of mechanical behaviour as claimed by the empirical method for the design of aeronautical bituminous pavements with abacus. The representation of the strain shapes was done with 3D and 2D profiles to improve the quality of response and to clearly identify the critical areas when an aircraft bogie is passing. The four- and six-wheels bogies of the aircraft A380 are more destructive to flexible pavements than the bogies of the other aircrafts tested in this study. The calculation of damage according to the new French rational method for aeronautical flexible pavements revealed that the main damage to these pavements is due to the fatigue of the bituminous layers and not the rutting of subgrade and the unbound granular material layers.

One‐Dimensional Fully Coupled Hydro‐Mechanical‐Chemical Model for Contaminant Transport Under Step‐Loading Condition and Its Analytical Solutions

ABSTRACTStepped dumpling of waste is the main operating method used in landfill engineering. For the liners located at the bottom of the landfill, the waste can be considered as a vertical loading due to its heavy weight, causing compressive deformation of the liners and, most importantly, tending to lose the effectiveness of the geomembrane with the differential deformation. However, most experiments or numerical models use transient‐loading and ignore the influence of variable step‐loading on liner performance. In this study, a one‐dimensional fully coupled hydro‐mechanical‐chemical (HMC) model for contaminant transport under the framework of small strain, taking into account the step‐loading effect, is proposed, and its analytical solutions are derived by using the separation of variables. The behavior of contaminant transport in a single‐layer clay liner is investigated under variable step‐loading conditions. Analytical results show that the step‐loading can significantly accelerate the transport of contaminants compared to the transient‐loading. Variation of the step‐loading rate from 2 to 4 times yields an increase of 6.1 and 15.2 years of the breakthrough time. At a step‐loading rate of 50 kPa/year, the breakthrough increases by 13.37 years, and the peak settlement reduces to half that under transient‐loading. Ignoring the influence of step‐loading on contaminant transport may overestimate the performance of clay liners.

Enhanced Electromagnetic Interference Shielding in Cement Composites Utilizing Carbon Fiber Clustered Networks with Dual Different Lengths

Electromagnetic interference (EMI) shielding is crucial for radio frequency ranges, particularly around 1 GHz, to ensure the functionality and security of electronic devices and wireless communications especially within building materials. The inherent properties of typical metallic materials, such as their heavy weight and high cost, make them less suitable for mass production, particularly in the construction applications. Herein, we present a novel approach to improve EMI shielding efficiency of cement composites by incorporating two types of carbon fibers with distinct lengths as fillers and optimizing the clustering network among these fillers. By precisely controlling the length and proportion of long (mother) and short (anchor) carbon fibers, we demonstrate that a 7:3 ratio of 6 mm mother fibers to 2 mm anchor fibers yields optimal shielding efficiencies, delivering 65.3 dB at a low radio frequency (1 GHz) and 44.5 dB in the high X-band frequency range (8.2 – 12.4 GHz). Significantly, two-dimensional matrix simulations corroborate the geometric modifications occurring between fillers as the length and ratio of carbon fibers are altered, showing excellent agreement with our experimental results. Combined with an intriguing approach to fine-tune the clustered network of carbon fibers, this study highlights the critical role of filler geometry within the matrix in developing high-performance EMI shielding materials, offering new insights for the design of advanced EMI shielding solutions.

Study on the Development of Yaw Stabilization Control Technique for Heavy Weight 2-axis Gimbal

Study on the Development of Yaw Stabilization Control Technique for Heavy Weight 2-axis Gimbal

Predisposing Factors of Delayed Onset of Muscle Soreness in Untrained Athletes: A Cross-sectional Study

Introduction: Delayed Onset Muscle Soreness (DOMS) is a common consequence of ultrastructural muscle damage. Following unusual eccentric exercises, individuals who are not professionally trained or are amateur athletes experience muscle tenderness that can range from mild discomfort to severe debilitating pain. Aim: To identify the factors that contribute to the development of DOMS in untrained athletes and to raise awareness about these factors. Materials and Methods: A cross-sectional observational study was conducted in the Department of Physiotherapy, GEMS College of Physiotherapy, Srikakulam, Andhra Pradesh, India on 50 untrained athletes aged 18-25 years, over a period of eight months from January to September 2022, with complete enrollment of untrained athletes. The history of pain, stiffness, decreased range of motion and DOMS was surveyed through a self-reported questionnaire, followed by quantitative statistical analysis using mean, standard deviation and percentages of the data. Results: The mean age of the participants was 21.04±2.7401 years. The current research examined various predisposing factors that influenced the occurrence of DOMS. Specifically, 35 (70%) athletes reported engaging in eccentric exercises; 24 (48%) athletes reported exposure to hot weather and outdoor environments; 32 (64%) athletes reported neglecting warm-up sessions; and 43 (86%) athletes reported skipping cool-down exercises. Conclusion: The study concluded that the group of muscles comprising the shoulders and biceps is particularly susceptible to experiencing pain, loss of strength, muscle tenderness and reduced range of motion as a result of DOMS. DOMS is commonly induced by engaging in high-intensity workouts, such as lifting heavy weights with eccentric contractions, without proper warm-up and cool-down routines, especially in hot outdoor environments.

Candidate SNP Markers Significantly Altering the Affinity of the TATA-Binding Protein for the Promoters of Human Genes Associated with Primary Open-Angle Glaucoma.

Primary open-angle glaucoma (POAG) is the most common form of glaucoma. This condition leads to optic nerve degeneration and eventually to blindness. Tobacco smoking, alcohol consumption, fast-food diets, obesity, heavy weight lifting, high-intensity physical exercises, and many other bad habits are lifestyle-related risk factors for POAG. By contrast, moderate-intensity aerobic exercise and the Mediterranean diet can alleviate POAG. In this work, we for the first time estimated the phylostratigraphic age indices (PAIs) of all 153 POAG-related human genes in the NCBI Gene Database. This allowed us to separate them into two groups: POAG-related genes that appeared before and after the phylum Chordata, that is, ophthalmologically speaking, before and after the camera-type eye evolved. Next, in the POAG-related genes' promoters, we in silico predicted all 3835 candidate SNP markers that significantly change the TATA-binding protein (TBP) affinity for these promoters and, through this molecular mechanism, the expression levels of these genes. Finally, we verified our results against five independent web services-PANTHER, DAVID, STRING, MetaScape, and GeneMANIA-as well as the ClinVar database. It was concluded that POAG is likely to be a symptom of the human self-domestication syndrome, a downside of being civilized.

Rechargeable Aqueous Lithium-Air Battery with Lithium Conducting Polymer Electrolyte Separator

Rechargeable lithium-air batteries are a promising high energy alternative to lithium-ion batteries. Two main types of lithium-air batteries are under development: non-aqueous lithium-air batteries and aqueous lithium-air batteries. The non-aqueous lithium-air batteries consist of a lithium anode and a carbon-based air electrode in a non-aqueous electrolyte, and offer high theoretical energy density of 3505 Wh kg-1 and 3436 Wh L-1. Over the past two decades, many researchers have developed non-aqueous lithium-air batteries. However, no technological breakthrough has been found to achieve these high energy densities. Aqueous lithium-air batteries consist of a lithium metal anode, a non-aqueous electrolyte, a lithium-ion conductive solid electrolyte that is stable in water, an aqueous electrolyte, and a carbon-air electrode. The cell reaction of this system is as follows1;4 Li + O2 + H2O ⇌ 4 (LiOH‧H2O) (1)The theoretical energy densities of this system based on equation (1) are 1910 Wh kg-1 and 2004 Wh L-1. Several problems in non-aqueous systems, such as electrolyte decomposition by reactive oxygen species and ingress of atmospheric moisture, do not occur in aqueous systems. In addition, LiOH, the discharge product of the air electrode, dissolves in the catholyte and does not interfere with the electrode reaction.NASICON-type lithium ion conductor of Li1+xAlxTi2-x(PO4)3 (LATP) has been mainly used for lithium ion conductive solid electrolyte separators, which is the key material for aqueous lithium-air batteries. Its ionic conductivity ranges from 10-3 to 10-4 S cm-1 at room temperature. The heavy weight of the solid electrolyte reduces the gravimetric energy density, but the degree of reduction is determined by the amount of electricity generated.2 The weight ratio of the LATP (100 μm thick) to the total cell weight (excluding the container) decreases from 0.55 at 10 mAh cm-2 to 0.42 at 20 mAh cm-2 and 0.25 at 50 mAh cm-2. The calculated energy densities are 551, 830, and 1190 Wh kg-1 for capacities of 10, 20, and 50 mAh cm-2, respectively. The area capacities reported in the literature are usually less than 10 mAh cm-2.3 Therefore, to improve the energy density of aqueous lithium-air batteries, the weight of the solid electrolyte must be reduced. However, LATP thin films less than 50 μm thick are not mechanically tough, making it difficult to use them as separators for these batteries.Recently, Toray developed a water-impermeable lithium-ion conductive polymer film.4 The film is less than 10 μm thick and the ionic conductivity is 3×10-5 S cm-1 at 25 °C. Using an H-type cell, pure water was placed in one chamber and a LiCl solution in the other, with this film placed in between. Since no chloride ions were observed in the pure water chamber for 200 hours, no water permeation was considered to have occurred.The test cell system consisted of a lithium metal anode, 4.5 M LiN(CF3SO2)2 in 1,2-diethoxyethane (DEE) anode, this separator, 1M LiOH-10 M LiCl, and a carbon air electrode. All experiments were conducted at 25 °C. A stable open circuit voltage (OCV) of 3.05 V was observed. This OCV is comparable to calculated values and those reported for aqueous lithium-air batteries with LATP separators.5 The total cell resistance was 350 Ω and the cell area was 1 cm2. The battery was successfully operated for 100 cycles at 0.2 mA cm-2 and 0.2 mAh cm-2.References N. Imanishi, Y. Takeda, O. Yamamoto, Electrochemistry, 80, 706 (2012)M.S. Park, S.B. Ma, D.J. Lee, D. Im, S.-G. Doo, O. Yamamoto, Scientific Reports, 4, Article number: 3815 (2014)N. Imanishi, O. Yamamoto, Materials Today Advances, 4, Article number: 100031 (2019)https://www.toray.co.jp/news/details/20220530165632.htmlS. Sunahiro, M. Matsui, Y. Takeda, O. Yamamoto, N. Imanishi, J. Power Sources, 262, 338 (2014) AcknowledgmentsThis work was supported by the program to Develop and Promote the Commercialization of Energy Conservation Technologies to Realize a Decarbonized Society of the New Energy and Industrial Technology Development Organization (NEDO; Japan) Grant Number JPNP 21005.

Impact of Growth Rate on the Welfare of Broilers.

Selection for the more efficient production of broilers has resulted in rapid growth rates. The aim was to review the existing knowledge on the effect of growth rate on broiler welfare. Genotypes with faster growth rates consistently demonstrate poorer gait scores and increased prevalence of disorders affecting their legs than slower-growing genotypes. Reduced mobility places faster-growing broilers at an increased risk of developing contact dermatitis, as they spend increased durations sitting in contact with litter. Poor walking ability, heavy body weights, and conformational differences such as proportionally larger breast muscle in genotypes with faster growth can impact a bird's ability to walk and navigate the environment, making it difficult to access resources and express natural behaviors. Faster growth has also been associated with poor cardiovascular health, increased susceptibility to heat stress, increased prevalence of mortality, ascites, as well as multiple breast muscle myopathies. Feed restriction, a practice associated with hunger and frustration, may be used to control the growth of broiler breeders, with birds having higher growth potential typically experiencing higher restriction levels. Overall, there is strong evidence that fast growth rates negatively impact welfare, and that slower-growing genotypes show significantly improved welfare. Furthermore, some evidence suggests that even minor reductions in growth rate can lead to welfare improvements.

Analysis of successful and unsuccessful snatch and clean and jerk lifts in IWF World Championships (2011–2023)

In this research, male and female athletes who won gold, silverand bronze medals at the International Weightlifting Federation Senior World Championship (between 2011 and 2023); (a) analysis of successful and unsuccessful lifts in snatch and clean and jerk techniques, (b) analysis of successful and unsuccessful lifts in 3 lift attempts in both techniques and, (c) It is aimed to investigate the lifting attempts of athletes that determine their medal rankings in snatch, clean and jerk and total. In this retrospective study, data of 3144 (1603 and 1541 for male and female, respectively) individual results obtained from the lifting performances of 528 athletes (male n = 270; female n = 258) participating in the Senior World Championship (between 2011 and 2023) in snatch and clean and jerk were analyzed. In the study, the frequencies and rates of the individuals included in the study according to different variables are presented with descriptive statistics. Various Chi-square analyzes were conducted to determine differences in distribution rates between groups. The significance level in the analyzes was determined as p < .05. It was determined that the successful lifts ratios of the athletes who achieved gold, bronze, silver medals in the light weight, middle weight and heavy weight categories of the male and female groups were higher than the unsuccessful lifts ratios in both lifting techniques (excluding silver medals in clean and jerk in lightweight for men; except bronze medals in snatch in lightweight for women). It was observed that the percentage rates in the unsuccessful lifts of athletes who achieved gold medals in both snatch and clean and jerk of the male and female groups were lower than the percentage rates in the unsuccessful lifts of athletes who took part in silver and bronze medals. It was observed that there was no significant difference between the distribution rates of successful and unsuccessful lifts distribution rates according to gender in both snatch and clean and jerk of both genders. It was observed that the successful lifts rates in both the snatch and clean and jerk of the male and female groups decreased from the 1st attempt to the 3rd attempt, and the lifting rates in the unsuccessful lifts increased. It has been observed that the lift attempts that determine the medal rankings of the groups in snatch, clean and jerk and total are the 2nd attempt and 3rd attempt. The findings can provide a comprehensive perspective on the in-competition factors that contribute to World Championship success in order to directly inform coach and athlete strategies. These findings may also be valid for national or regional champions and may include other strength-based sports with a similar structure.

Which risk factors are involved in a distal biceps tendon injury? A systematic review.

Distal biceps tendon rupture is a rare injury predominately occurring in middle-aged men. This study aimed to collect relevant risk factors associated with distal biceps tendon rupture from the published literature. This systematic review aimed to collect and tabulate the risk factors for distal biceps tendon rupture. Studies published in English were searched concerning risk factors for distal biceps tendon ruptures until July 2022; cohort studies, case series and randomized controlled trials were subjected to analysis. Case studies, cadaveric studies and reviews in any form were excluded. The studies were quantitatively and qualitatively reviewed. One hundred twenty-one articles presenting risk factors for distal biceps tendon ruptures were identified, recruiting a total of 7,484-7,576 patients. The average age of the individuals was 46.8 years, with 96.7% being males and 94.7% having affinity for sports activities. In 56.7% of the cases, the dominant arm was involved, and in 54.6%, the right arm was affected. The use of tobacco was found in 20.8% of cases and of anabolic steroids in 2.5% of cases. On average, 55.8% of distal biceps tendon rupture patients had a physical occupation and the most common mechanism of the injury was related to heavy weight lifting observed in 53.2% of subjects. The most common and outstanding reported risk factors for distal biceps tendon ruptures were age, sex and sports activity, i.e., middle-aged males being still physically active and practicing sports. Steroid usage does not seem to increase significantly the risk of the distal biceps tendon rupture.

Costs of Disabling Musculoskeletal Pain in Children and Adolescents: A Cost-of-Illness Prospective Cohort Study

OBJECTIVES: To (1) estimate the economic cost of disabling musculoskeletal pain in children and adolescents from a health care and societal perspective, (2) identify the characteristics of children and adolescents with higher costs, and (3) estimate the economic cost of children's pain to Brazil. DESIGN: Prospective cohort study. METHODS: We recruited children and adolescents with disabling musculoskeletal pain from public and private schools. The economic cost associated with disabling musculoskeletal pain was reported by parents each month for 1 year. The cost categories were health care, lost productivity, and patient/family costs. The sum of the categories resulted in the societal costs. Costs were reported using means, standard errors, medians, interquartile ranges, confidence intervals, and sum for each cost category. We compared participant characteristics between groups with low and high costs, and estimated the health and social cost of children's pain to the Brazilian federal budget. RESULTS: We included 237 children and adolescents with mean age of 11.8 years (standard deviation, 2.9). Total annual health care costs were $29.58 and $103.13 for health insurance/public health care and out-of-pocket, respectively, per child. Total annual societal costs were $177.62 per child. Individuals in low socioeconomic class E (with a monthly income of up to R$403.00) reported that heavy backpack weight, practice of fewer days of sports, and more negative psychosomatic symptoms were associated with higher health care costs. The annual costs to Brazil from the societal perspective was $1 001 329 553. CONCLUSION: Disabling musculoskeletal pain in children and adolescents in Brazil imposes a serious economic burden of up to $1 billion on the federal budget. J Orthop Sports Phys Ther 2024;54(12):1-10. Epub 4 November 2024. doi:10.2519/jospt.2024.12735.

Vibration optimization methods of dredger engine room

Abstract Due to the large number and heavy weight of equipment, as well as the high center of gravity in the cabin area of dredgers, the concentrated arrangement of equipment is prone to local vibration problems in the cabin area. Additionally, there are many devices that need to be placed under the deck in the cabin area, which imposes significant constraints on the placement of supports. Using the finite element method to analyze the vibration problem of a certain dredger, we studied the influence of different equipment arrangements and structural reinforcement methods on vibration. This allowed us to summarize the characteristics of vibration under different improvement methods, providing feasible solutions for improving the vibration problem in the cabin area of dredgers. After adjusting the equipment layout and reinforcing local structures, the vibration in the dredger’s cabin area ultimately meets the design requirements satisfactorily.

In Situ Experimental Analysis and Performance Evaluation of Airport Precast Concrete Pavement System Subjected to Environmental and Moving Airplane Loads.

The behavior of airport precast concrete pavement (APCP) involving new design and construction concepts was experimentally analyzed under environmental and moving airplane loads, and the long-term performance of the APCP was evaluated using fatigue failure analysis. The strain characteristics and curling behavior of the APCP under environmental loads were comprehensively analyzed. The APCP slabs exhibited a pronounced curling phenomenon similar to conventional concrete pavement slabs. The dynamic response of the APCP subjected to impact loads was analyzed by performing heavy weight deflectometer tests. The test results confirmed that the vertical deformation of the APCP was small and within the typical range of vertical deformation of conventional concrete pavement. The dynamic strain response of the APCP under moving airplane loads was then analyzed and the strain variation during day and night times was compared. The strains during the day were found to be significantly larger than those at night under airplane loads because of the curling phenomenon of the APCP slabs. Finally, the long-term performance of the APCP was evaluated using fatigue failure analysis based on the obtained behavior. Even using the most conservative fatigue failure prediction model, the service life of the APCP was ascertained to be more than 30 years. Based on the overall results of this study, it is concluded that the APCP, which is designed to reduce slab thickness by placing reinforcing bars in the slabs via reinforced concrete structural design, exhibits typical behavior of concrete pavements and can be successfully applied to airport pavement rehabilitation.

Subgrade performance assessment for rigid runway using long-term pavement performance database

Maintaining desired subgrade performance is an effective way to reduce runway pavement deterioration. Due to lack of extensive field test data, life-cycle performance of runway subgrade has not been fully understood. In order to quantitatively estimate subgrade condition, a novel method of evaluating subgrade performance was developed and validated using the 726 sets of Heavy Weight Deflectometer (HWD) test data of ten runway sections. Statistical analysis demonstrates that the structural behaviour of rigid runway subgrade follows normal distribution in different service stages and can be efficiently evaluated by the subgrade performance index (ψ). The results of factor analysis show that Accumulated Air Traffic Volume (ATV) during service life is the major cause of spatial variations in subgrade condition. In the designed service period of runway, it validates that sea-reclaimed subgrade results in faster degradation in the initial stage of service life while thicker pavement exhibits better capability in protecting the subgrade soil in long-term view. Besides, the differences in applied loads and pavement thickness give rise to the subgrade performance variation in longitudinal direction. Meanwhile, the comparison between the main and the less trafficked test lines in transversal direction reveals that the aircraft impacts play a positive role in resisting the natural fatigue process. By the suggested method, subgrade performance of HWD test points can be categorized into 4 levels from “Excellent”, “Good”, “Fair” to “Poor” based on ψ value. It is helpful for airport agency to make scientific decisions on Maintenance and Rehabilitation (M&amp;R) treatment by calculating the effective area of envelope (β) using the ratio of subgrade performance (η).

Development of Low-Resistance Coastal Stow Net Using Numerical Analysis and Model Experiments

In coastal stow net fishing, the heavy weight of a typical anchor (750–1000 kg) can increase the risk of capsizing the boat and crew member injury during hoisting operations. Thus, to prevent these accidents, a reduction in the anchor weight is required. One strategy to achieve this is to reduce the resistance force of the fishing gear used, which would allow lighter anchors to be employed. This requires the accurate estimation of the resistance force for various gear designs. Therefore, the resistance force and shape during the operation of two representative types of coastal stow nets currently employed in the Korean coastal stow net fishing industry were investigated using simulations and modeling experiments. The modeled fishing gear was divided into four sections according to the mesh size. Based on the results, the twine thickness was reduced in order to target areas of the gear where the greatest resistance was observed, while the front part of the gear was redesigned to prevent the front of the net from being pushed back into a suboptimal shape. The proposed low-resistance fishing gear has the potential to improve occupational safety in the coastal stow net fishing industry.