Prótesis fija reforzada con fibra de vidrio como opción restaurativa a la prótesis fija convencional

Current in situ piezoresistive damage detection techniques for fiberglass-reinforced composites are limited in widespread application as they require complex processing techniques which inhibit the scalability of the methods. To eradicate such challenges and expand the use of piezoresistive monitoring of fiberglass composites, this work utilizes a simple, scalable process to coat electrically insulating commercial fiberglass prepreg with piezoresistive laser induced graphene (LIG) for the detection and localization of damage. Recently, LIG has attracted substantial research attention due to the simplicity of the methodology and the piezoresistance of the LIG. Here, the LIG is transfer printed onto commercial fiberglass prepreg which is subsequently used to localize damage in all three dimensions of the resultant fiberglass-reinforced composites while also maintaining the structural properties of the composites. A combination of in situ and ex-situ resistance measurements are used to accomplish this objective: First, in situ measurements are used to determine the relative location of damage in one-dimension under tensile loading. Subsequently, separate in situ measurements are used to locate damage through the thickness under flexural loading. Finally, ex-situ methods are used to calculate the two-dimensional location of a hole in a plate. The LIG is found to reliably and accurately localize the damage to the composite in each case thus demonstrating for the first time that transfer printed LIG enables self-sensing of damage location in fiberglass composites. The result of this work is thus a multifunctional material capable of locating damage in all three-dimensions which is notably fabricated using commercial materials and scalable methodology.

BackgroundMany clinical questions arise during patient encounters that clinicians are unable to answer. An evidence-based medicine approach expects that clinicians will seek and apply the best available evidence to answer clinical questions. One commonly used source of such evidence is scientific literature, such as that available through MEDLINE and PubMed. Clinicians report that 2 key reasons why they do not use search systems to answer questions is that it takes too much time and that they do not expect to find a definitive answer. So, the question remains about how effectively scientific literature search systems support time-pressured clinicians in making better clinical decisions. The results of this study are important because they can help clinicians and health care organizations to better assess their needs with respect to clinical decision support (CDS) systems and evidence sources. The results and data captured will contribute a significant data collection to inform the design of future CDS systems to better meet the needs of time-pressured, practicing clinicians.ObjectiveThe purpose of this study is to understand the impact of using a scientific medical literature search system on clinical decision making. Furthermore, to understand the impact of realistic time pressures on clinicians, we vary the search time available to find clinical answers. Finally, we assess the impact of improvements in search system effectiveness on the same clinical decisions.MethodsIn this study, 96 practicing clinicians and final year medical students are presented with 16 clinical questions which they must answer without access to any external resource. The same questions are then represented to the clinicians; however, in this part of the study, the clinicians can use a scientific literature search engine to find evidence to support their answers. The time pressures of practicing clinicians are simulated by limiting answer time to one of 3, 6, or 9 min per question. The correct answer rate is reported both before and after search to assess the impact of the search system and the time constraint. In addition, 2 search systems that use the same user interface, but which vary widely in their search effectiveness, are employed so that the impact of changes in search system effectiveness on clinical decision making can also be assessed.ResultsRecruiting began for the study in June 2018. As of the April 4, 2019, there were 69 participants enrolled. The study is expected to close by May 30, 2019, with results to be published in July.ConclusionsAll data collected in this study will be made available at the University of Queensland’s UQ eSpace public data repository.International Registered Report Identifier (IRRID)DERR1-10.2196/12803

The scientific literature search is a crucial enabler for the research process and one of the most problematic and inefficient activities that researchers must face. Most University students never experience scientific literature search, although research is the primary mission of the universities and one of the major activities of their professors and a primary parameter for their careers. The aim of this paper is to i) present a new approach for scientific literature search based on virtual team collaboration, ii) explore the team dynamics of the knowledge building process in a virtual environment and, iii) propose a blog tool for open knowledge sharing both for experienced researchers and beginning students. An experiment on a collaborative scientific literature search on five virtual teams for a total of 25 students at the 2nd edition of the 2nd level Master in Valorization of different abilities and education research proposed by the CAFRE Interdepartmental Center for Lifelong Learning, Training and Education Research at Pisa University has been developed. The collaboration result is a Google Sites embedding individual blogs where each virtual team can build and share organized knowledge based on literature search.KeywordsMethodologies for distance learningCollaborative literature searchEdublogVirtual teamwork

The effect of the composition of high strength concretes with low water to binder ratio and silica fume on the development of splitting tensile strength was studied. A statistical approach was employed to develop formulation which could adequately describe the relations between splitting tensile strength and the concrete composition, when cured in two different regimes: water curing at 20°C and sealed curing at 30°C. Autogenous shrinkage was induced in the second type of curing but was largely eliminated in the first one. The relations were presented as nomograms which could be used as a basis for mix design. The correlation between tensile splitting strength and compressive strength could not be described in terms of a simple linear relation with a characteristic constant. For the range of variables studied, the ratio between tensile and compressive strength varied over a large range of 0.08 to 0.12. As a result, the relations developed here for tensile strength are quite different in nature than those for compressive strength in a previous study. Analysis of the data suggest that tensile strength is sensitive to effects which induce autogenous shrinkage to a much greater extent than compressive strength. It is proposed that this may be the main reason for the different trends observed for the relations between the composition of the low water/binder ratio concretes and their compressive and tensile strength.

Investigation of mechanical properties of high-performance concrete via multi-method of regression tree approach

The strength characteristics ofSporosarcinal Pasteuriiconcrete (S. Pasteurii concrete)was investigated.To achieve this aim, the suitability of the materials used for concrete specimens weretested before the compressive, tensile and flexural strength of the S.Pasteurii concrete was investigated.Bacteria concentration of 0, 0.5, 2, 4 and 6OD was mix with the concrete. The water cement ratio adapted was 0.5.For the compressive strength, three cubes of size 150 x 150 x150mm was crushed for each curing day of 1, 3, 7,14, 28 and 56 days. The average compressive strength was obtained as the compressive strength of the concrete at eachcuring age. For the split tensile strength, three cylindrical specimen of size 100mm x 200mm was used at each day to obtain the strength at 7, 14, 21 and 28 days. The average tensile strength was obtained and for the flexural strength, three beam samples of 100 x 100 x 450mm was used at each curing day of 7, 14, 21 and 28days to obtain the average flexural strength.All the properties of the materials used for the concrete production met the standard requirement of the relevant code of practice. The compressive, tensile and flexural strength of S. Pasteurii concrete was improved in comparison with the control concrete. The percentage increase of the compressive strength at 28days are 17.76%, 19.72%, 25% and 4.04% for 0.5OD, 2OD, 4OD and 6OD respectively.The highest tensile strength was increased by 16.24% and obtained when 0.5OD bacteria concentration was used and cured for 14days. The flexural strength of S. Pasteurii concrete was improved by 44.44%, 8.89%,47.40% and 8.52% for 0.5OD, 2OD,4OD and 6OD respectively at 28 day of curing.

Analysis of strength properties of light-cured resin composites

Composite concrete such as fiber reinforced concrete is widely used in structures because of its excellent properties such as compressive, flexural and tensile strengths and also high modulus of elasticity because it gives lower strain values under loading and too fewer cracks propagation. In this study, Aluminum strips was prepared by cutting the Coca- Cola cans as strips in concrete. The reason of using Aluminum strip is low density and good tensile strength (about 310 MPa) and also has a good ductility. The results of this study show good improvements in compressive, tensile and flexural strengths using 117 tested specimens for both concrete and mortar. In brief, about 22 % increment in compressive strength of Aluminum strip concrete and flexural strength increases from 3.31 MPa to 11.20 MPa when using Aluminum strips with 2.5 % by volume of concrete. The reinforced mortar with Aluminum strips demonstrates significant increments which are 27% for compressive strength and more than 100% for both flexural and tensile strengths comparing with reference mix.

Engineered cementitious composites (ECC) are an ultra-ductile cement-based composite material reinforced with short randomly distributed fibers. It differs from fiber reinforced concrete (FRC) in that it has a distinct ductile behavior. The study aims to assign mechanical properties, such as tensile, flexural, and compressive strength using locally available fiber rather than polyvinyl alcohol (PVA) fiber, which is not widely available in many countries, to ECC. PVA fiber is also very expensive. Instead of PVA, lightweight fibers, such as polypropylene, polyolefin, and glass fiber, as well as heavyweight fibers, such as steel fiber, were used. To assess the mechanical properties, the influences of curing, fiber volume fraction (2%, 4%, and 6%), fiber type, and fiber hybridization were adjusted in this study. The formation of multiple cracks along the specimen is the governing factor in ECC formation. The test results show that increasing the fiber volume fraction improves flexural and tensile strength. Water curing increased compressive, tensile, and flexural strength. Lightweight fiber hybridization has no effect on compressive strength, whereas heavyweight fiber hybridization improves compressive strength. For tensile and flexural strength, hybridization was associated with an improvement in all mechanical properties. The hybridization of lightweight fiber achieved ECC behavior at a lower volume fraction than the use of a single fiber volume. Relationships between tensile strength and flexural strength depending on the compressive strength of ECC were driven by demonstrating high performance.

To elevate the progressive utilization of natural fiber reinforced composites in structural applications, it is extremely required to heighten the properties of NFRC’s by the exploitation of hybridization tool. In most of the cases, the mechanical properties of hybrid composites reinforced with natural fibers are far better than the pure single fiber reinforced composites and comparable to the synthetic fiber reinforced composites. Therefore in this research work, an experimental investigation has been carried out to study the mechanical properties and water absorption behavior of hybridized PALF/COIR fiber reinforced epoxy matrix composites. The biocomposite sheets consist of randomly oriented and intimately mixed short fibers (20 mm in length) were fabricated by employing the hand lay-up technique at 11 levels of COIR fiber loading (0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 vol%) with fixed total fiber content (40 vol%). The mechanical properties (tensile strength, tensile modulus, flexural strength, flexural modulus, and impact strength) and water uptake behavior with water diffusion mechanism of various formulated composites have been studied according to ASTM standard. The total of four samples for each composite specimen was tested and their average values were reported. The results showed the improvement in tensile and flexural properties (strength and modulus) of COIR/Epoxy composite by the hybridization with pineapple leaf fiber, up to 50 vol%. The hybrid composite reinforced with equal volume content of pineapple leaf fiber (PALF) and coconut husk fiber (COIR) possess the highest tensile, flexural, and impact strength. Water absorption test revealed the decrement in sorption affinity with the increase of coir fiber content. The hybrid composite (P50-C50) absorbs 62% and 32% less water than that of pure PALF/Epoxy and COIR/Epoxy composites.

This research deals with the development of knitted hollow composites from recycled cotton fibers (RCF) and glass fibers (GF). These knitted hollow composites can be used for packaging of heavy weight products and components in aircrafts, marine crafts, automobiles, civil infrastructure, etc. They can also be used in medical prosthesis or in sports equipment. Glass fiber-based hollow composites can be used as an alternative to steel or wooden construction materials for interior applications. Developed composite samples were subjected to hardness, compression, flexural, and impact testing. Recycled cotton fiber, which is a waste material from industrial processes, was chosen as an ecofriendly alternative to cardboard-based packaging material. The desired mechanical performance of knitted hollow composites was achieved by changing the tube diameter and/or thickness. Glass fiber-reinforced knitted hollow composites were compared with RC fiber composites. They exhibited substantially higher compression strength as compared to cotton fiber-reinforced composites based on the fiber tensile strength. However, RC fiber-reinforced hollow composites showed higher compression modulus as compared to glass fiber-based composites due to much lower deformation during compression loading. Compression strength of both RCF- and GF-reinforced hollow composites decreases with increasing tube diameter. The RCF-based hollow composites were further compared with double-layered cardboard packaging material of similar thickness. It was observed that cotton-fiber-reinforced composites show higher compression strength, as well as compression modulus, as compared to the cardboard material of similar thickness. No brittle failure was observed during the flexural test, and samples with smaller tube diameter exhibited higher stiffness. The flexural properties of glass fiber-reinforced composites were compared with RCF composites. It was observed that GF composites exhibit superior flexural properties as compared to the cotton fiber-based samples. Flexural strength of RC fiber-reinforced hollow composites was also compared to that of cardboard packaging material. The composites from recycled cotton fibers showed substantially higher flexural stiffness as compared to double-layered cardboard material. Impact energy absorption was measured for GF and RCF composites, as well as cardboard material. All GF-reinforced composites exhibited higher absorption of impact energy as compared to RCF-based samples. Significant increase in absorption of impact energy was achieved by the specimens with higher tube thickness in the case of both types of reinforcing fibers. By comparing the impact performance of cotton fiber-based composites with cardboard packaging material, it was observed that the RC fiber-based hollow composites absorb much higher impact energy as compared to the cardboard-based packaging material. The current paper summarizes a comparative analysis of mechanical performance in the case of glass fiber-reinforced hollow composites vis-à-vis recycled cotton fiber-reinforced hollow composites. The use of recycled fibers is a positive step in the direction of ecofriendly materials and waste utilization. Their performance is compared with commercial packaging material for a possible replacement and reducing burden on the environment.

The analysis of underground oil-shale recovery processes requires knowledge of the mechanical properties of oil shale at various temperatures. The tensile strength, compressive strength, and Young's modulus are of special importance. The variation of these properties with temperature is important when assessing the strength of underground columns and confining walls for process cavities. This paper presents the results of an experimental study to quantify this temperature dependence. We found that both tensile and compressive strengths of oil shale show a marked decrease in strength as temperature increased, for a given richness. For example, for 15.6 gal/ton oil shale, the tensile strength at 400 deg. F is only 28% of its room temperature value. For 19.2 gal/ton shale, the compressive strength at 400 deg. F with 500-psi confining pressure is 43% of its value at room temperature. At a given temperature, both the tensile and compressive strengths decrease as richness increases, although the rate of decrease diminishes at richnesses of about 42 gal/ton and higher. Equations are developed to permit estimates of the various parameters involved. The compressive Young's moduli show a considerable decrease with temperature. At 400 deg. F the modulus is reduced to 51% of its room temperature value. Introduction In-situ processes for recovery of oil from nahcolite-bearing oil shale usually involve some heating or pyrolysis of the shale. Wet processes (steam, hot water) also involve dissolution of nahcolite to generate pore space and to create permeability. If the leaching of nahcolite is conducted at a sufficiently high temperature, some stress will develop in the rock beyond the heated cavity boundary because of CO2 generation and possibly water vapor, as follows. 2NaHCO3 goes to Na2CO3 + H2O + CO2. When the decomposition pressure of nahcolite is high enough, the rock tends to fracture ("popcorn effect"). Rubbling of the formation then can occur. To predict conditions suitable for fracturing and rubbling, we need to know how the rock tensile strength varies with temperature. McLamore measured the oil-shale tensile strength as a function of orientation of stress. So far as we know, no measurements of tensile strength as a function of temperature have been reported for oil shale. We also need to know the variation of nahcolite decomposition pressure with temperature. This pressure variation was measured by Templeton. The variation of Young's modulus, compressive strength, and Poisson's ratio also have been reported for various richnesses. Logan and Heard studied the compressive Young's modulus and thermal expansion as functions of richness. Compressive strength of oil shale has been studied extensively. This parameter was measured as a function of oil-shale richness for various confining pressures in triaxial tests at temperatures up to 300 deg. C (572 deg. F). The effect of temperature on rocks other than oil shale has also been studied. Knowledge of the compressive strength is important when assessing the possibility of failure of underground supporting walls in mines or with process cavities. Since the reacted oil shale probably will support the walls or the roofs of the process cavities very little, the strength of the supporting walls and roof under process conditions will determine the tendency for subsidence or intercavity communication. SPEJ P. 301^

Tendinopathies are overuse tendon injuries showing load-dependant pain, stiffness, weakness of movement in the affected area, and impairment in the movements. The scientific interest on the role of Hyaluronic Acid (HA) for the management of tendinopathies has been increased due to its anti-inflammatory and lubricative properties. To collect evidence regarding the effectiveness and safety of HA injections in reducing pain in patients affected by tendinopathies. A scientific literature search was conducted using the PubMed, Medline and PEDro electronic databases. The databases were searched since their inception until July 2021. The search was limited to English language articles. Different combinations of the terms and MeSH terms "tendinopathy", "tendinosis", "tendinitis", "hyaluronic acid", "hyaluronate", "infiltration", "hyaluronic injections", "viscosupplementation" connected with various boolean operators were used for other electronic databases. One hundred and one records were identified from the selected databases plus three additional papers identified by the authors through other sources. After removing duplicated papers and title/abstract screening, 19 studies were included in our review (eight papers on shoulder, three on elbow, four on hand, one on knee, and three on ankle). The results showed that none of the studies report severe adverse effects and most of them support the use of HA injections in tendinopathies, with a special attention to pain reduction and functional assessment. Further studies are warranted to better investigate effects and methods of administration of HA in tendinopathies.

Background/Objectives: Adolescent idiopathic scoliosis (AIS) is a three-dimensional deformity of the spine that can negatively impact on quality of life, pulmonary function, and body image. Its conservative management includes various interventions, among which the Schroth method stands out. This approach is based on three-dimensional corrective exercises and rotational breathing. This review aimed to analyze the effectiveness of the Schroth method, applied either alone or in combination with other conservative therapies, on variables such as Cobb angle, angle of trunk rotation (ATR), pulmonary function, and health-related quality of life in patients with AIS. Methods: A scientific literature search was conducted using the PubMed database. We searched for randomized controlling trials (RCTs), systematic reviews, and meta-analyses reported in English from 2020 to 2025. Different combinations of the terms and MeSH terms “adolescent”, “idiopathic”, “scoliosis”, and “Schroth” connected with various Boolean operators. Results: Overall, 82 articles were reviewed from the selected database. After removing duplicated papers and title/abstract screening, 13 studies were included in our review. The results showed that the Schroth method proved effective in reducing the Cobb angle and ATR, particularly in patients with mild curves and in early stages of skeletal growth. Improvements were also observed in health-related quality of life and aesthetic perception, and to a lesser extent, in pulmonary function. Moreover, therapeutic adherence and treatment continuity were important to maintaining long-term benefits. Conclusions: The Schroth method could be an effective treatment associated with orthopedic treatment, yielding satisfactory results. Its implementation requires structured programs, professional supervision, and strategies to enhance therapeutic adherence. Nevertheless, to validate its long-term effectiveness, we need more homogeneous studies with longer follow-up durations.

The load from vehicles received by rigid pavement is characterized as dynamic load that move and change quantitively, so the r2eaction accepted by rigid pavement is the combination of compressive and tensile strength. In the reaserch, as the effort to know the effect of flexural and split tensile strength on normal quality concrete with 0%, 0,4%, 0,6% and 0,8%. The samples of flexural tensile strength testimonial use 60 cm x 15cm x 15 cm beam and the sampes of split tensile and compressive strength test use 15 cm x 30 cm cylinder. As the result, the concrete sample with 0,4% of volume fraction has the most significant progress in the flexural tensile strength, split tensile strength and compressive strength. The result of this research also shows that the progress of flexural tensile test sample reach 9,42%, split tensile strength 7,5% and compressive strength 6,12% from concrete sample with 0% of volume fraction and it has decreased test result from 0,6% and 0,8% of volume fraction. The maximum of flexural tensile test, split tensile test, and compressive test are 6,62 MPa, 2,58 MPa, and 30,54 MPa. Key words : Melaleuca bark fiber, flexural tensil strength,split tensil strength, compressive strength, volume fraction, and rigid pavement.