Comparison of microparticle transport and deposition in nasal cavity of three different age groups.

Objective: The nasal cavity effectively captures the particles present in inhaled air, thereby preventing harmful and toxic pollutants from reaching the lungs. This filtering ability of the nasal cavity can be effectively utilized for targeted nasal drug delivery applications. This study aims to understand the particle deposition patterns in three age groups: neonate, infant, and adult.Materials and methods: The CT scans are built using MIMICS 21.0, followed by CATIA V6 to generate a patient-specific airway model. Fluid flow is simulated using ANSYS FLUENT 2021 R2. Spherical monodisperse microparticles ranging from 2 to 60 µm and a density of 1100 kg/m3 are simulated at steady-state and sedentary inspiration conditions.Results: The highest nasal valve depositions for the neonate are 25% for 20 µm, for infants, 10% for 50 µm, 15% for adults, and 15% for 15 µm. At mid nasal region, deposition of 15% for 20 µm is observed for infant and 8% for neonate and adult nasal cavities at a particle size of 10 and 20 µm, respectively. The highest particle deposition at the olfactory region is about 2.7% for the adult nasal cavity for 20 µm, and it is <1% for neonate and infant nasal cavities.Discussion and conclusions: The study of preferred nasal depositions during natural sedentary breathing conditions is utilized to determine the size that allows medication particles to be targeted to specific nose regions.

Enhancement of rider comfort by magnetorheological elastomer based damping treatment at strategic locations of an electric two wheeler.

The vibrations generated in the two-wheeled vehicles like motorcycles due to road irregularities such as cracks, potholes, and bumps on the road cause discomfort for the rider as well as the pillion. These vibrations are reported to cause lower back pains, musculoskeletal effects, fatigue, and long-term health issues. Particularly, electric two-wheelers are more susceptible to these vibrations caused by the road and need attention. This paper presents an innovative technique for the reduction of vibrations at prominent locations in the electric two-wheeler to improve the rider's comfort. All measured accelerations are about vertical direction (along z-axis as per ISO 2631-1 standard). Passive and Semi-active damping treatments namely, Room temperature vulcanizing Silicone rubber and Magnetorheological elastomer (MRE) were applied on the test vehicle at strategic locations of vibration. Both were compared for their effectiveness in reducing the vibrations. Results showed that MRE based damping technique proved better vibration isolation at the strategic locations. The weighted root mean square acceleration as well as vibration dose values were found to decrease with the help of damping treatments thus improving the rider's overall comfort level.

Computational fluid dynamics study of respiratory mask for neonatal resuscitation.

Face cups form a vital component of breathing, assisting with devices that aid in artificial breathing for neonates. This study aims to evaluate the flow parameters in the nasal cavity for two different types of face cups. The neonatal nasal cavity model was developed from CT scans using MIMICS 21.0. Two face cups, one hemispherical and the other anatomical shaped cups are developed around the nasal cavity and the airflow is simulated using ANSYS 2021 R2. Results are compared with a nasal-only model. At the nasal valve region, the highest velocity is seen for the nasal-only model which is 16.3% higher than that of the hemispherical face cup and 15.2% superior to the anatomical-shaped face cup. In addition, the decrease in pressure across the nasal-only model is 7.4 and 6.6% below that of the hemispherical cup and anatomical cup masks. The nasal resistance values across the nasal cavity are the lowest for the nasal-only model, 7.7 and 6.7% lower respectively than the hemispherical and anatomical-shaped cups. There were very minor changes in the flow parameters such as velocity, pressure and wall shear stress when comparing the hemispherical and anatomic-shaped masks for the airflow inside the nasal cavity.

A rapid supercritical water approach for one-pot synthesis of a branched BiVO4/RGO composite as a Li-ion battery anode.

The application of novel one-dimensional (1D) architectures in the field of energy storage has fascinated researchers for a long time. The fast-paced technological advancements require reliable rapid synthesis techniques for the development of various Multi-metal oxide (MMO) nanostructures. For the first time, we report the synthesis of a single-phase hierarchical one-dimensional (1D) branched BiVO4-Reduced Graphene Oxide (BVONB/RGO) nanocomposite with different weight percent variations of RGO starting from 6, 12, 24, and 26 wt% using the supercritical water method (SCW). The affirmation of the sample characteristics is done through various nano-characterization tools that help in establishing the monoclinic crystal structure, and nano branch morphology along with its physical, and thermal characteristics. Further, the electrochemical behavior evaluations of the fabricated coin cells provide insights into the well-known superior initial cycle capacity of around 810 mA h g-1, showing the superior ability of BVONB structures in storing lithium-ions (Li-ions). Meanwhile, an improved cyclic performance of the pure BVONB/RGO with 260 mA h g-1 is evident after 50 cycles. Finally, the reported rapid single-pot SCW approach has delivered promising results in establishing a material process technique for multimetal oxides and their RGO nanocomposites successfully.

Patient-specific finite element analysis for assessing hip fracture risk in aging populations.

The femur is one of the most important bone in the human body, as it supports the body's weight and helps with movement. The aging global population presents a significant challenge, leading to an increasing demand for artificial joints, particularly in knee and hip replacements, which are among the most prevalent surgical procedures worldwide. This study focuses on hip fractures, a common consequence of osteoporotic fractures in the elderly population. To accurately predict individual bone properties and assess fracture risk, patient-specific finite element models (FEM) were developed using CT data from healthy male individuals. The study employed ANSYS 2023 R2 software to estimate fracture loads under simulated single stance loading conditions, considering strain-based failure criteria. The FEM bone models underwent meticulous reconstruction, incorporating geometrical and mechanical properties crucial for fracture risk assessment. Results revealed an underestimation of the ultimate bearing capacity of bones, indicating potential fractures even during routine activities. The study explored variations in bone density, failure loads, and density/load ratios among different specimens, emphasizing the complexity of bone strength determination. Discussion of findings highlighted discrepancies between simulation results and previous studies, suggesting the need for optimization in modelling approaches. The strain-based yield criterion proved accurate in predicting fracture initiation but required adjustments for better load predictions. The study underscores the importance of refining density-elasticity relationships, investigating boundary conditions, and optimizing models throughin vitrotesting for enhanced clinical applicability in assessing hip fracture risk. In conclusion, this research contributes valuable insights into developing patient-specific FEM bone models for clinical hip fracture risk assessment, emphasizing the need for further refinement and optimization for accurate predictions and enhanced clinical utility.

Multiple impact effects of helium-driven shocks on thin fiber-metal laminates.

Fiber Metal Laminates (FMLs) have garnered considerable attention and are increasingly being utilized in the development of protective armors for explosion and ballistic scenarios. While most research has focused on assessing the response of FMLs to single impacts, real battlefield situations often require shielding structures to endure multiple impacts. Thus, this study revolves around the creation of hybrid FMLs designed for shock shielding purposes. The primary focus is on how these laminates withstand repetitive impacts from high-intensity shock waves, aiming to pinpoint the optimal sequence that offers the highest resistance against multiple shock impacts. To establish effective shielding, a multi-layered FML configuration is employed. This configuration incorporates AA6061-T6 facing plates, ballistic-grade synthetic materials like aramid/epoxy ply, and ultra-high molecular weight polyethylene (UHMWPE)/epoxy ply. Additionally, a paperboard/epoxy lamina is introduced to induce functional grading based on layerwise shock impedance mismatches. Shock impact experiments are conducted using a shock tube equipped with helium as the driver gas. Critical shock parameters, including Mach Number, positive impulse, and peak overpressure, are meticulously evaluated. For validation purposes, a numerical model is employed to project the damage profile as a function of radial distance across different laminate sequences. The study unveils that ply deformations are strongly influenced by the arrangement of core layers, particularly the positions of the paperboard and UHMWPE layers within the core structure. To contextualize the findings, the shock impact results obtained from this study are compared with those from prior experiments that employed nitrogen-driven shocks.

Wear estimation of hip implants with varying chamfer geometry at the trunnion junction: a finite element analysis.

The hip joint helps the upper body to transfer its weight to lower body. Along with age, there are various reasons for the degeneration of the hip joint. The artificial hip implant replaces the degenerated hip. Wear between the joints is the primary cause of the hip implant becoming loose. The wear can occur due to various reasons. Due to this revision surgery are most common in young and active patients. In the design phase of the implant if this is taken care then life expectancy of the implant can be improved. Small design changes can significantly enhance the implant's life. In this work, elliptical-shaped hip implant stem is designed, and linear wear is estimated at trunnion junction. In this work, a 28 mm diameter femoral head with a 4 mm thick acetabular cup and a 2 mm thick backing cup is used. The top surface taper radiuses are changed. Solid works was used to create the models. Ansys was used to perform the analysis. It was found that as the radius of the TTR decreased, the wear rate decreased. The least wear rate was found in 12/14 mm taper with a value of 1.15E-02mm year-1for the first material combination and with a value of 1.23E-02mm year-1for the second material combination. In the comparison between the models with 1 mm chamfer and no chamfer, it was found that the wear rate was lower for the models with 1 mm chamfer. When the chamfer was increased (more than 1 mm), the linear wear increased. Wear is the main reason for the loosening of hip implants, which leads to a revision of an implant. It was found that with a decrease in TTR, there was a small increase in the linear wear rate. Overall, the implant with TTR 6 mm and a chamfer of 1 mm was found to have the least wear rate. To validate these results, the implant can be 3D printed and tested on a hip simulator.

Whole body vibration and rider comfort determination of an electric two-wheeler test rig.

Background: Two-wheeled vehicles are the major mode of transportation in India. Such vehicles are exposed to excessive vibration on the road when compared to four-wheeled vehicles. However, the research on the reduction of whole body vibration in the case of two-wheelers is not explored in detail. The present study predicts rider comfort in the case of an electric two-wheeler as per ISO 2631-1, by obtaining the finding the weighted acceleration at the strategic locations of vibration at the test rig. Methods: An electric two-wheeler test rig is used in the study. The values of acceleration from the test rig in running conditions are obtained by using NI LabVIEW 2019. The drive cycle of the electric vehicle (EV) test rig is controlled by Sync sols' EV lab software. Obtaining the weighted root mean square (RMS) acceleration from running the test setup, it is compared with the ISO 2631-1 standard to obtain the rider comfort. Results: Loading area, traction motor, base mount, and suspension were found to be the strategic points of vibration. Frequency weighted RMS acceleration of 0.3 to 0.4 m/s 2 obtained at these points are prone to cause discomfort for the rider. Vehicle speed, road profile, and duration of exposure were found to be important parameters affecting the rider's comfort. A maximum of 4.6 m/s 2 amplitude was observed. The loading area, which corresponds to a rider's seat in actual vehicle, is important and reduction of these vibrations make the ride comfortable for the rider. Suspension and base mount of the test rig are found to be uncomfortable observing the weighted RMS acceleration. Conclusions: A suitable damping technique design is very much essential in reducing these vibrations and improve the rider comfort, as many more non-deterministic vibrations are prone to cause dis-comfort in case of actual on road riding conditions.

Finite element analysis of elliptical shaped stem profile of hip prosthesis using dynamic loading conditions.

Patient-specific dynamic loadings are seldom considered during the evaluation of hip implants. The primary objective of this study is to check for the feasibility of the use of UHMWPE as the material for an acetabular cup o CoCr Alloy that is reported to produce a squeaking sound after replacement. An elliptical shaped stem with three different cross-sectional profiles is considered for simulation. Using a commercial finite element method, patient-specific dynamic forces were applied for the quantitative analysis. The loading and boundary conditions are used as per ISO and ASTM standards. The walking gait cycle is used with two widely used biocompatible materials: titanium and cobalt-chromium. Initially, only the stem is considered for the analysis to finalize the best out of the three profiles, along with the better material for the stem. Later the complete implant is used for the analysis. Profile 1 exhibits 1.25 and 1.17 times greater stress than Profile 2 for CoCr Alloy and Ti-6Al-4V, respectively. Similarly, Profile 3 displays stresses 1.26 and 1.25 times greater than Profile 2 for CoCr Alloy and Ti-6Al-4V, respectively. Comparatively, displacement in stem Profile 2 is 1.75 times higher in Ti-6Al-4V than CoCr Alloy. The full implant displacement at 14% gait cycle is 1.15% higher for the CoCr-acetabular column material combination when compared to UHMWPE. It can be concluded that UHMWPE can be used as the acetabular cup material instead of CoCr for the Profile 2 elliptical shaped hip implant to prevent squeaking after replacement.

Nasal airflow comparison in neonates, infant and adult nasal cavities using computational fluid dynamics.

BACKGROUND AND OBJECTIVE: Neonates are preferential nasal breathers up to 3 months of age. The nasal anatomy in neonates and infants is at developing stages whereas the adult nasal cavities are fully grown which implies that the study of airflow dynamics in the neonates and infants are significant. In the present study, the nasal airways of the neonate, infant and adult are anatomically compared and their airflow patterns are investigated. METHODS: Computational Fluid Dynamics (CFD) approach is used to simulate the airflow in a neonate, an infant and an adult in sedentary breathing conditions. The healthy CT scans are segmented using MIMICS 21.0 (Materialise, Ann arbor, MI). The patient-specific 3D airway models are analyzed for low Reynolds number flow using ANSYS FLUENT 2020 R2. The applicability of the Grid Convergence Index (GCI) for polyhedral mesh adopted in this work is also verified. RESULTS: This study shows that the inferior meatus of neonates accounted for only 15% of the total airflow. This was in contrast to the infants and adults who experienced 49 and 31% of airflow at the inferior meatus region. Superior meatus experienced 25% of total flow which is more than normal for the neonate. The highest velocity of 1.8, 2.6 and 3.7 m/s was observed at the nasal valve region for neonates, infants and adults, respectively. The anterior portion of the nasal cavity experienced maximum wall shear stress with average values of 0.48, 0.25 and 0.58 Pa for the neonates, infants and adults. CONCLUSIONS: The neonates have an underdeveloped nasal cavity which significantly affects their airway distribution. The absence of inferior meatus in the neonates has limited the flow through the inferior regions and resulted in uneven flow distribution.

Wear estimation of trapezoidal and circular shaped hip implants along with varying taper trunnion radiuses using finite element method.

BACKGROUND AND OBJECTIVE: The hip joint is the vital joint that is responsible for the bodyweight transfer from the upper body to the lower body. Due to age these joints are worn out and need to be replaced by artificial hip implants. Wear is the predominant factor that is responsible for the loosening of hip implants. The wear occurs between the joints due to various reasons. The wear estimation at the design stage gives a clear idea about the life of the implants and also minor changes in the design may also significantly increase the life expectancy of the implant which can further reduce the rate of revision surgery. The linear wear rate is estimated in the taper trunnion surface. METHODS: In this study, the circular and trapezoidal-shaped stem implant is designed, and wear studies are performed at the trunnion junction. The femoral head of size 28 mm, acetabular cup thickness of 4 mm, and a backing cup of thickness 2 mm are considered for the study. The neck taper radiuses at the top surface are altered. Ansys is used to perform the simulations. RESULTS: At the time of assembly of the femoral head into the stem, the stresses were found to be increasing with an increase in the top surface radius of the neck taper junctions. However, when the walking conditions are considered for wear estimation of implants the circular implants with the 12/14 mm taper exhibited the lesser linear wear rate of 0.003 mm/year. The trapezoidal implants with the 10/14 mm taper exhibited a lesser linear wear rate of 0.032 mm/year. CONCLUSIONS: Wear is an important parameter that leads to the revision of implants due to loosening. It is found that with the decrease in the taper radius at the top surface against the standard 12/14 mm taper there is no significant decrease in the wear rate at the taper junction. Overall the circular implants exhibited less wear rate results over the trapezoidal-shaped stem implants. Due to the less linear wear rate, the circular implant has a higher life over the trapezoidal-shaped implant. Further, these implants can be manufactured to test using a hip simulator with the same conditions to validate the obtained results.

Corrigendum to "Static structural analysis of different stem designs used in total hip arthroplasty using finite element method" [Heliyon Volume 5, Issue 6, June 2019, Article e01767].

[This corrects the article DOI: 10.1016/j.heliyon.2019.e01767.].

Static structural analysis of different stem designs used in total hip arthroplasty using finite element method.

BACKGROUND: The Hip joint is the primary joint which gives stability to the human body. The wear and tear associated with age and other factors, require these joints to be replaced by implants using hip arthroplasty surgeries. Cobalt chromium alloy (CoCr), titanium alloy, stainless steel are some of the most common hip joint materials used for hip implants. The design requirement for hip joint implants are very stringent to avoid revision joint surgeries due to aseptic loosening. There are various choices in shapes and materials used for stem and acetabular designs. This makes it more difficult to make an informed decision on the type of design and material that can be used for hip implants. METHODS: Circular, Oval, ellipse and trapezoidal designs with three individual cross sections (defined as profile 1, profile 2 and profile 3) are considered for the study. All models are modeled using CATIA V-6. Static structural analysis is performed using ANSYS R-19 to arrive at the best possible design and material combination for stem and acetabular cup. RESULTS: It was found that, profile 2 of all the four designs has the lowest possible deformation and von Mises stress when compared to profile 1 and profile 2. In general, profile 2 with trapezoidal stem has best outcomes in terms of its mechanical properties. Besides, stem designed with material CoCr and its associated acetabular cup with CoC (ceramic on ceramic) material can produce an implant having better properties and longer durability. CONCLUSIONS: CoCr was found to be the preferred choice of material for stem design. It was also observed that, irrespective of material considered for the analysis profile 2 with trapezoidal stem showcased lesser deformation and von Mises stress over the other eleven models. For analysis involving acetabular cups, CoC implants exhibited better mechanical properties over the conventional CoPE (Ceramic on polyethylene) materials such as Ultra-high molecular weight polyethylene (UHMWPE). It is inferred from the findings of this study that, the profile 2 with trapezoidal stem design made of CoCr material and acetabular cup made of CoC material is best suited for hip joint implants.