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Go to Editorial ManagerMany joints in the body depend on cartilage for their mechanical function. Since cartilage lacks the ability to self-heal when injured, treatments and replacements for damaged cartilage have been created in recent decades. The mechanical tests had an important role in the treatment and designing of the replaced cartilage. There are two types of cartilages in the knees: fibrocartilage (the meniscus, it is a special type of cartilage) and hyaline cartilage. Its mechanical properties are important because structural failure of cartilage is closely related with joint disorders. This study aimed to determine the stress-strain curve to give broader understanding of the material’s properties. The results of this study could help to develop computational models for evaluating mechanics of knee joint, predicting possible failure locations and disease progression in joints.The study involved two specimens taken from bovine, the first was the articular cartilage with subchondral bone and the second was the meniscus cartilage each one loaded on a compressive testing machine to compute the displacement, and the force applied, enabling the calculation of the stress-strain curve of the material.Specimen failure occurred in the articular cartilage surface at a force break of 73.8N and get force peak about 87.2 N. The meniscus cartilage failure had occurred at a force break of 29.2 N and get force peak about 34.9 N.
This work has studied the size of the mean time between failures (MTBF) because it has a vital role in assessing reliability in manufacturing systems. Previous studies have indicated that the reliability value depends on the size of MTBF, so they indicated only 11 types of time that reliability value depends on, and they used methods of DFR and RCM to enhance the reliability level. To assess and increase reliability value, this work referred to the four main times: mean time between failures (MTBF), mean time to diagnosis (MTTD), mean time to repair (MTTR), and mean time to failure (MTTF) in more detail. Also, it designed a new arrangement of failure notification time, failure diagnosis time, downtime, failure repair, testing time, and recovery periods for ongoing operations in manufacturing systems through a new redistribution of 19 times and time intervals in detail between the four main times, so it revealed and added 8 types of other times and time intervals more than previous studies because they have vital roles in increasing reliability value. Thus, the new arrangement contains two parallel pathways and 19 types of times and time intervals. The first pathway represents 5 positions and 11 types of start and end times; the second pathway represents 4 positions and 8 time intervals. Consequently, MTBF becomes longer because the new arrangement shortens the time distances between the start of failure and repair process end, between diagnosis end and test, and between inspection end and the system's return to normal operating conditions. The motivations are to raise the reliability value, quality level, and effective maintenance and save costs. This work used the data collection and analysis method. The results showed that there is a higher reliability for manufacturing systems when the time arrangement is better, MTBF is longer, MTTD is shorter, MTTR is smaller, MTTF is longer, and the error rate is lower.
A tack coat is a minimal coating of asphalt cement, cut-back asphalt, or asphalt emulsion to an existing pavement surface between layers to guarantee proper bonding between the two layers and longitudinal and transverse joints. Numerous researchers have assessed interlayer adhesion employing failure-mode behavior tests, such as pull-off, direct shear, and torsion testing. This study aims to quantify the best tensile resistance obtained using three types of cutback asphalt (RC70, RC800 modified with polymer 4.5% & MC70). All are applied on concrete surfaces at a rate of 0.5 L/m². The Proceq DYNA Z16 pull–off tester is used to measure the tensile strength at a rate of 0.25 kN/s. It is found that the average tensile strength of the tack coat materials is (0.319, 0.138, 0.028) MPa, respectively. It is concluded that RC70 has the maximum tensile strength. Also, the different types of solvent affect adhesion strengths; RC70 was Prepared using gasoline, while MC70 used petroleum. Gasoline has greater volatility and thus increased adhesion. Failure strength modes of interior bonding varied between cohesive failure adhesive and adhesive failure.
The main objective of this study was to model the left ventricle (LV) based on 2D echocardiography imaging technique to assess the cardiac mechanics for group of patients affected by heart failure. A prospective study has been made at Ibn Al-Bitar center for cardiac surgery, for 13 patients with heart failure (HF), 9 patients were males (69%) and 4 females (31%). The mean age was 54±7 years. Those patients were supposed to undergo a CRT-D (Cardiac Resynchronization Therapy Defibrillator) implant as they didn’t respond to drug therapy. Before CRT-D implantation, 2D echocardiography was performed for all the patients, to model the left ventricle and to measure indices that were used to evaluate cardiac mechanics which are LV pressure, wall stresses, global longitudinal strain, and cardiac output. After 3-months of follow-up, 2D echocardiography was re-assessed and the left ventricular mechanics has been re-measured. Post CRT-D implantation, significant improvement in the cardiac mechanics was observed in 54% of the patients which were called responders (patients that respond to CRT-D device) and the other patients were called non-responders. It has been seen that, the circumferential wall stresses were decreased in responder’s group while increased or remain unchanged in non-responders. Global longitudinal strain for the responder’s group were increased while remain unchanged in the non-responders. So, patients were divided into responders and non-responders, based on improvement of the cardiac mechanics after 3-moths of follow up. It has been concluded that the modelling of the left ventricle based on images obtained from 2D echocardiography imaging techniques, was an important computational tool that was used to enhance understanding and support the evaluation, surgical guidance and treatment management of basic biophysics underlying cardiac mechanics.
The behaviour of slabs under impact loading differs significantly from that observed under short-term or long-term static loading conditions. Such dynamic loading scenarios typically arise from vehicular collisions, explosive events, or other forms of sudden impact. This paper aims to synthesise and critically evaluate the extant literature concerning the response of slabs subjected to impact loading. The investigation encompasses an analysis of the salient factors influencing slab behaviour, elucidation of failure mechanisms, examination of methodologies for simulating impact loading, and a critical appraisal of pertinent design code recommendations. Through this comprehensive review, it has been ascertained that reinforcement configuration plays a pivotal role in augmenting the resistance of slabs to impact loading. Furthermore, the predominant mode of failure observed in such scenarios is punching shear. This finding underscores the necessity for meticulous consideration of shear capacity in the design of impact-resistant slab structures.
Structural elements. This means the structural behavior can be quantified by considering the behavior of each structural element in each load path. Concrete is a material known for its great strength. Regardless, there are a few weaknesses, which must be taken in consideration in the design of concrete structural elements. Basically, concrete is made of three main ingredients: Portland cement, water, and aggregates (sand and stone).In order to improve tensile strength and ductility (capacity to stretch and deform prior to failure) in concrete, so this paper discus some types of concrete and record the effect on beams. Reactive powder concrete (RPC) is an actual concrete mixture, it is a special type of concrete because mix concrete (coarse and fine aggregate ) replaced by fine sand size (150-400)µm. In the experimental comparison the mechanical properties( compressive , splitting tensile and flexural )strength of plain RPC and high and normal strength concrete. Each set consisted of (4) cubes of (100×100×100_mm, (8) cylinder of (150×300mm) and (4) prism of (100x100x500) mm and consisted of (4) beam of (1000×100×400)mm. The results shown that the maximum compressive strength is 107 MPa and the maximum splitting tensile 9 MPa of RPC comparison high and normal strength concrete. The result of the second part shown increased RPC reinforced concrete the firstcrack288 MPa and ultimate crack 380MPa comparison high and normal strength concrete and the mode of failure of RPC (flexural-shear).
A dam failure results in losses in terms of economy and infrastructure, in addition to the loss of many lives and assets. Inadequate seepage control procedures are typically the cause of seepage failure in earth-fill dams. For an earthen dam to be waterproof and to minimize seepage, non-homogeneous dams with a clay core are one kind of embankment dam used. As water moves through the dam's core, friction causes it to lose a lot of energy. Both vertical and inclined cores can be used in the design and construction of zoned embankment dams. As a result, choosing the proper materials and dimensions for the earth dam's core is critical. The main objective of this study is to investigate different seepage control strategies for an earth dam (HORAN DAM) using the Finite Element Method (FEM). We modeled and analyzed nine cases of various seepage control techniques that have been modeled and analyzed using SEEP/W, a FEM-based software. The modeling results show using chimney filters reduces pore water pressure more effectively than using toe rock and horizontal filters. Regarding seepage, trapezoidal cores perform better than inclined cores, and the milder slope is preferred over steeper core slopes. The results show when the core permeability decreases, the seepage quantity also decreases. Toe rock decreases seepage more than horizontal filters and chimney filters. Additionally, it has been shown that using a toe rock filter together with a trapezoidal core with a mild slope performs better than using a different filter and a different internal clay core shape.
This article provides a general up to date review of the investigation on performances and resistances of plain and fiber containing concrete structures under periodical loadings of long endurance up to fatigue failure. Structures are almost, under the frequent influences of repeated loadings such as vibrations of rotary machines, sea /river waves, wind, earthquakes and moving vehicles. Long term application of cyclic loading leads to continually slow rate degradation of the structure rigidity leading to fatigue damage. In spite of the dominant usage of concrete, worldwide, as a building material, its fatigue behavior is not straight forward. In addition, this lack of comparison is confronted for fiber fortified concrete. The article also presently a survey of the available techniques for monitoring and measurement of fatigue impressions in concrete structures founded both their impact within the treatise domain and the non-destructive inspection. Those technical means are classified into, at least, two designations, specifically, the monitoring of fatigue induced cracking and the detection of fatigue charged damage. Those techniques parameters, evaluate the changes in the mechanical and physical materials properties during the fatigue endurance, are distantly reviewed in concern of the mechanism creating the change, shortcomings, constraints, etc. The merits, dependency, feasibility, disadvantages and limitations of each technique are assessed and compared to make an index to select the appropriated e technique for fatigues fracture or failure inspection of the type fibered or not of structural concrete
Additionally, it has been demonstrated that osseointegrated implantation offers superior proprioception and control over the prosthesis, enabling more natural movement and improved functional results. Additionally, it lowers the chance of falling and increases energy transfer efficiency, making it simpler for amputees to engage in physical activity. Furthermore, as compared to conventional socket prosthesis attachment, osseointegrated implantation has been linked to higher patient satisfaction and quality of life._x000D_ It is crucial to remember that osseointegration is a surgical operation with risks including infection and implant failure. Additionally, for effective implantation, it needs a specific amount and quality of bone, which may restrict its usage in some individuals. Furthermore, osseointegrated implantation could be more expensive than conventional socket prosthetics._x000D_ Understanding the efficacy and safety of this method requires research on complication rates and outcome metrics in patients having osseointegrated prosthesis implantation. You may acquire information on things like infection rates, implant failure, patient satisfaction, and functional results by studying original research papers. Clinical decision-making can then be improved with the use of this information._x000D_ In transfemoral amputees, osseointegration has showed promise as a powerful substitute for socket prostheses. A growing corpus of research has shown that osseointegrated implantation provides advantages in terms of increasing mobility, decreasing discomfort, and improving general quality of life. The efficiency of osseointegration for transtibial and upper extremity implants has received little attention._x000D_ Minor soft tissue infections are the most frequent consequences, although they are manageable with the right treatment and monitoring. To further reduce the risk of problems and improve the overall success of osseointegrated implantation, research and development are ongoingly focused on enhancing surgical methods and implant design._x000D_ Although osseointegration has a lot of potential, not all amputees may be good candidates for it. Considerations for osseointegrated implantation must take into consideration elements including the degree and nature of the amputation, the quality and density of the bone, and the desires of the patient.
Rutting is considered as the most generated distress in Iraqi roads as a result of the high temperature and excessive traffic load. So, it is essential to utilize polymer modified binder to increase the performance of pavements. The objective of this paper is to assess the effect of aggregate gradation and filler content on the rutting formation of Colored Hot Mix Asphalt CHMA. The HMA was colored by using iron oxide as filler to produce red HMA. Two blends were used: fine and coarse with two different types of filler iron oxide for CHMA and limestone for conventional HMA with two filler content 6% and 10%. Neat (AC 40-50) and modified asphalt (AC 40-50 + 4%SBS) were used. Tests are held on adding 4% Styrene Butadiene Styrene )SBS( by the weight of neat asphalt (AC 40-50) to raise the performance grade by two grades from PG (64-16) to PG (76-16) [1] and [2]. The wheel tracking test is used to assess the rut depth of the CHMA. The test results showed that the using iron oxide with neat asphalt increase the rut depth resistance by 200 and 400 failure load cycles than mixtures using limestone (cycles that mix reach 25 mm rut depth) for fine and coarse mix respectively. Also, the effect of gradation shows that the fine mixture fails at 4000 cycles while the coarse mixture fails at 1800 cycles for 6% limestone mixtures. Increasing the iron oxide content from 6% to 10% leads to increase the failure load cycles by 2200 and 1200 cycles for fine and coarse mixture respectively using modified asphalt. The fine mixture with 10% iron oxide using modified asphalt gives the best performance with 7000 cycles than the coarse mixture with 10% filler content and modified asphalt with 4000 cycles. irrespective the filler and type of binder, the dense mixtures using iron oxide as filler exhibit better resistance to rutting formation than coarse mixtures.
Kidney disease is a global health concern, often leading to kidney failure and impaired function. Artificial intelligence and deep learning have been extensively researched, with numerous proposed models and methods to improve kidney disease diagnosis. This work aims to enhance the efficiency and accuracy of the diagnostic system for kidney disease by using Deep Learning, thereby contributing to effective healthcare delivery. This work proposed three models: CNN, CNN-XGBoost and CNN-RF to extract features and classify kidney Ultrasound images into four categories: three abnormal cases (stones, hydronephrosis, and cysts) and one normal case. The models were tested on a real dataset of 1260 kidney ultrasound images (from 1000 patients) collected from the Lithotripsy Centre in Iraq. CNN models are often viewed as black boxes due to the challenge of understanding their learned behaviors, Visualizing Intermediate Activations (VIA) was used to address this issue. The proposed framework was assessed based on precision, recall, F1-score, and accuracy. CNN-RF is the most accurate model, with an accuracy of 99.6%. This study can potentially assist radiologists in high-volume medical facilities and enhance the accuracy of the diagnostic system for kidney disease.
In this study, previous researches were reviewed in relation to the seismic evaluation and retrofitting of an existing building. In recent years, a considerable number of researches has been undertaken to determine the performance of buildings during the seismic events. Performance based seismic design is a modern approach to earthquake resistant design of reinforcement concrete buildings. Performance based design of building structures requires rigorous non-linear static analysis. In general, nonlinear static analysis or pushover analysis was conducted as an efficient instrument for performance-based design. Pushover analysis came into practice after 1970 year. During the seismic event, a nonlinear static analysis or pushover analysis is used to analyze building under gravity loads and monotonically increasing lateral forces. These building were evaluated until a target displacement reached. Pushover analysis provides a better understanding of buildings seismic performance, also it traces the progression of damage and failure of structural components of buildings.
The field of mechanics concerned with studying the propagation of cracks in materials is Fracture Mechanics. Technology systems are meant to withstand the loads to which they are likely to be exposed when in use. Material imperfections arising at the time of production or use of the material are, however, unavoidable and must therefore be taken into account. A stress intensity factor is a fracture parameter that defines the part failure. This paper study’s the effect of cracks on the stresses of rectangular plates having a hole in the center. The plate was subjected to tensile pressure at the top side while maintaining the bottom side fixed. The plate had four cracks distributed around the centered hole at 45o at each side. The effect of the length of the cracks on the resulted stresses and strains was investigated. Also, the effect of the position of the crack on the resulted stresses and strains was studied. Finite element models for the different plate cases were built using ANSYS software. The results showed that increasing the crack length resulted to increase the stresses and strains. The dimension of the plate width, height and thickness were 150 mm, 300 mm and 1 mm respectively, and the crack position was investigated for different crack lengths (5, 10, 15, 20, 25 mm) however the results were not steady as it looks that the crack lengths have changed the stress distribution over the plate.
Kidney renal failure is a life-threatening disease in which one or both kidneys are not functioning normally. The only available treatment other than a kidney transplant is to start on dialysis sessions, whether it is peritoneal or Hemo-dialysis[1].For some patients, the dialysis procedure is an exhausting and sometimes expensive trip to the specialized dialysis centers since it must be done about three times a week, depending on the physician's decision depending on the glomerular filtration rate of the kidneys[2-4].Different researchers have made many attempts over the years to replace conventional dialysis machines with more accessible at-home dialysis systems to provide patients with comfortable treatment sessions at the time they want without the need to change their lifestyle to fit the dialysis center's schedule.A review of the critical methods utilized in the creation and application of a portable dialysis machine that resembles the traditional dialysis center devices was conducted using a number of prior studies (research conducted between 2009 and 2024); the goal of all studies was to create a device that consists of filtering system, detection system to ensure there is no blood leakage and all parameters are within the acceptable limits, alarm system, and dialysate regeneration system, and each method will be described precisely in this review.As a result, the discussed studies found that using peristaltic pump pumps with a phase difference by half cycle between blood and dialysate will cause a higher urea clearance rate; multiple studies focused on the modification of the dialyzing filter to find that using Polyethene glycol surface-modified silicon nanopore membranes, dual-layer hollow fiber membranes, the use of BRECS cell therapy, carbon activated blocks, all contributed highly in enhancing the dialyzing process providing the patients with highly efficient blood purification session.
Recently, considering polymer composite in manufacturing of mechanical parts can be caused a fatigue failure due to the very long time of exposure to cyclic loading and may at environmental temperatures higher than their glass transition temperature; therefore, in this paper, a comprehensive investigation for bending fatigue behavior at room and elevated temperatures equal to 60 °C, 70°C, and 80 °C will be done. Rotating bending test machine was manufactured for this purpose supplied with a connected furnace to perform fatigue tests at elevated temperatures. The obtained results appeared that the increase in applied stress and temperature caused a clear reduction in fatigue life; also the addition of carbon nanotubes enhanced the fatigue life at different temperatures by 183%, 205%, 218%, and 240%, respectively while the addition of short carbon fibers improved fatigue life by 324%, 351%, 387%, and 415%, respectively. As well as, Polyamide 6,6/carbon fiber composite appeared fatigue limit at temperatures equal to 20°C and 60°C and stresses approximately equal to 55 MPa and 38 MPa respectively.
The aim of this study was to support surgeons to decide where to place the screws in order to achieve an optimal fracture healing and to prevent implant failure after a femoral shaft fracture So this paper focus on the analysis of bone-plate construct by using Finite element Analysis (FEA), comminuted femur fractured bone fixed with Dynamic Compression Plate (DCP) 16 holes by 4.5 Cortex screws, to investigate the effects of screws configuration on the mechanical behavior of different seven model as Interfragmentary strain which is the most important factor for femur fracture healing. The results state the relationships between the Von-Mises stress, Total deformation and Interfragmentary strain with respect to the screws configuration. The study shows the regions of maximum stress from stress distribution and also founded that we can decrease the Interfragmentary strain by increasing the number of screws.
The effects of the ultrasonic peening treatment (UPT) on the rotating bending fatigue behavior and the behavior of the vibrations of alloy steel DIN 41Cr4 were studied. Hardness test, Tensile test, Constant amplitude fatigue tests, and the vibrations measurements have been carried out on the specimens. Also, the fracture surface was examined and analyzed by a Scanning Electron Microscope (SEM). The results of the investigations, e.g. stress to number of cycles to failure (S-N) curves, fatigue strength improvement factor was 7%. The decreasing percentage of maximum Fast Fourier Transform (FFT) acceleration of the ultrasonic peened condition compared to the untreated conditions was 45%.
Moisture-induced damage in asphalt pavements, is defined by adhesive failure at the binder-aggregate interface and decreased mechanical integrity, severely reduce pavement durability. The research examines the mechanical properties and moisture sensitivity of hot mix asphalt (HMA) enhanced with styrene-butadiene-styrene (SBS) polymer and including reclaimed asphalt pavement (RAP). Laboratory assessments, including indirect tensile strength (ITS) and tensile strength ratio (TSR) tests, were performed on conventional HMA, SBS-modified HMA (4% SBS), and SBS-modified HMA contained 20% RAP. The results indicated that SBS modification significantly improved mechanical and moisture resistance properties, where unconditioned ITS specimens increased by 37.1% and TSR value enhanced by 13.5%. The incorporation of RAP decreased ITS value by about 21 % relative to pure SBS-modified HMA; nevertheless, the SBS+RAP combination still show higher ITS and TSR values than conventional HMA.
Contemporary urban discourse is paying increasing attention to the issue of urban resilience, due to the stresses, disasters and disturbances (natural and human) that the cities of the world are experiencing and facing, which confirms the need to be familiar with the concept of urban resilience, its dimensions, practices, and characteristics at different levels; In order to reach the aspects of developing the urban energy sector in them, and in a way that supports the preparedness of cities to face potential expected and unexpected disturbances in the future, as cities are usually formed from many main and sub-systems that are dynamically intertwined with each other, such as: the social and economic system, infrastructure systems, land use, and media Various transports, which have a high level of direct interactions with the natural environment; ; It is therefore necessary to understand how the city deals with the odds of threats and challenges in an integrated manner; To overcome its weaknesses and enhance its resilience of use, which aims to make cities more secure, resilient and sustainable in the future, as well as that requires rethinking the field of expanding the use of renewable energies and the general urban landscape. To become a search problem “Failure to exploit the potential of natural energies on the possibility of exploiting renewable natural energies with their components (active and passive) in the production of resilience urban formations in cities.” The aim of the research is to try to "extract an integrated theoretical framework on the characteristics of urban energy resilience from international and Arab experiences, and to diagnose its most important planning and design pillars and indicators, which can be adopted to evaluate the reality of urban energy resilience in local cities." The research hypothesized that “the exploitation of energy systems produced from renewable natural resources, for the purposes of environmental treatments for resilient cities, especially in the buildings of housing projects and their urban surroundings, reduces the consumption of fossil energies for the city, frees its sites from linking to depleted energy transmission networks, and reduces potential environmental pollution problems, which contributes to in the production of flexible energy systems and helps in the generation of flexible cities." The descriptive analysis method was adopted.