Higher Stress Values Research Articles

Examining the bending test properties of bio-composites strengthened with fibers through a combination of experimental and modeling approaches

This study explores the relationship between natural fiber filling density (10%, 15%, 25%) and its impact on the bending properties of polymer compounds reinforced with Diss, Sisal and Luffa fibers. Using advanced techniques like fiber analysis and Fourier transform infrared spectrometry (FTIR), the research reveals that a 25% filling density results in the highest stress values (25.61 MPa, 22.21 MPa and 20.88 MPa) for Diss, Sisal and Luffa compounds, respectively, fostering robust bonds in Diss-reinforced polymers. The Artificial Neural Network (ANN) model demonstrates superior predictive capability with correlation coefficients exceeding 0.99 for stress and displacement, outperforming Response Surface Methodology (RSM). Analysis of Variance (ANOVA) underscores the impact of sample section parameters and fiber rate on stress, establishing the significance of type parameters and fiber rate on displacement. This integration of ANN and RSM represents a paradigm shift in predicting bending mechanical properties, advancing our understanding of composite materials for innovative applications.

Preparation and properties of montmorillonite incorporated natural rubber/ethylene propylene diene monomer rubber blends

This article aims to evaluate and compare two types of organic surface-modified-nanoclay of octadecylamine-modified-bentonite-nanoclay (ODA-BNC) and aminopropyltrimethoxysilane-octadecylamine-modified-nanomontmorillonite (APS-ODA-MMT). Each type of nanoclay is combined with silica as a bi-filler for natural rubber (NR)/ethylene propylene diene monomer rubber (EPDM) in a 50/50 blend ratio for possible vulcanized rubber nanocomposite application. The total filler content is 50 phr while nanoclay filler content ranges from 0 to 20 phr, keeping the other ingredients ratio fixed. The prepared composites are characterized by the Fourier transform infrared spectrophotometer (FTIR) and their mechanical and thermal properties are thoroughly investigated. The data reveal that the fillers added to the rubber can improve its surface properties according to their type and amount as confirmed by the Atomic force microscope (AFM), and Scanning electron microscope (SEM) investigation. The surface of rubber containing APS-ODA-MMT displayed higher height (251) and roughness surface (94.11), than those (69.8) and (45.62) respectively, containing ODA-BNC. Moreover, the acid resistance of the prepared composites is verified and indicated that increasing the nanoclay ratio (20%) enhances the acid resistance by reducing the surface distortion while keeping the surface morphology. The mechanical properties and Thermogravimetric Analysis (TGA) measurements showed that the rubber containing ODA-BNC has higher values of stress (2.2), elongation (975), and thermal stability (470, 505, 520°C) than those (1.75), (650), and (440, 460, 470°C) respectively, containing the APS-ODA-MMT. Moreover, the durability investigation of the vulcanized rubber via the AFM found the modified composites can be used in harsh environments as a covering layer in petrochemical networks or chemical factories.

Finite Element Analysis of the Effect of Femoral Prosthesis Varus and Valgus Angle Installation on the Lateral Compartment in Unicompartmental Knee Arthroplasty.

This study used finite element analysis (FEA) to investigate the effect of varus and valgus angle on the lateral compartment in unicompartmental knee arthroplasty (UKA). One patient who underwent UKA was enrolled as the subject. Thirteen working conditions of the femoral prosthesis were simulated at varus and valgus angles of 0°, 2°, 4°, 6°, 8°, 10°, and 12°. A load of 1,000 N was applied downward along the mechanical axis of the femur, and the highest stress values on the surface of the polyethylene liner, cancellous bone under the tibial prosthesis, cartilage of femur lateral condyle, lateral meniscus, and tibial lateral plateau cartilage in each model were recorded. The six highest points were used to calculate the mean value. The highest stress values on the surface of the polyethylene liner, cancellous bone under the tibial prosthesis, cartilage of femur lateral condyle, lateral meniscus, and tibial lateral plateau cartilage increased with an increase in the femoral prosthesis varus/valgus angle. As compared with the standard position of the femoral prosthesis, there was no significant difference in the surface stress values of the polyethylene liner, cancellous bone under the tibial prosthesis, cartilage of femur lateral condyle, lateral meniscus and tibial lateral plateau cartilage when the femoral prosthesis varus/valgus angle was less than 4° (p > 0.05). In addition, the stress magnitude on the polyethylene liner, cancellous bone under the tibial prosthesis, cartilage of femur lateral condyle, lateral meniscus, and tibial lateral plateau cartilage significantly increased when the femoral prosthesis varus/valgus angle was greater than 4° (p < 0.001). The optimal femoral prosthesis varus/valgus angle in UKA was less than 4°.

N28 Stress and Inflammatory Bowel Disease – are there any differences during flare and remission?

Abstract Background Patients with Inflammatory Bowel Disease (IBD) often experience that stress has a negative effect on the disease. Studies have also shown a possible connection between stress and active IBD. This study aims to investigate the patients´ level of stress (both subjective and objective) in relapse and in remission. With this information we may determine if the levels of stress are higher in active disease compared to remission. Methods Inclusion criteria were having diagnosis with ulcerative colitis or Crohn`s disease, being over 18 years old, and having a flare in IBD. Measurements were made in cortisol in saliva and filling in the questionnaires Short Health Scale (SHS) and Perceived Stress Scale (PSS). All measurements were done at the beginning of the flare and then a second time when the patient was classified as being in remission. Flare and remission were determined by endoscopic examination and fecal calprotectin. Results A total of 20 patients completed the study. Median age was 45 years. A number of 17 (85%) had ulcerative colitis, and 12 (60%) were women. The levels of cortisol showed normal values both in active disease and in remission. Neither the results in PSS showed any differences between active and non-active disease. However, the results showed medium high values of stress in both measurements (table 1). SHS showed improvements in all four questions, but mostly in question 1 concerning symptoms. Conclusion No significant differences could be found in levels of stress when measuring cortisol and experienced stress in flare and in remission. However, the PSS showed that the participants had medium high levels of stress at both measurements. This could indicate a more constant stress in patients with IBD. A weakness in this study is the difficulty in measuring cortisol at the same time in each patient. Another weakness is the small population. There is still a need to examine the connection between stress and IBD. Concerning this study there is a wish to more closely investigate possible differences within each patient.

Incomplete insertion of pedicle screws triggers a higher biomechanical risk of screw loosening: mechanical tests and corresponding numerical simulations.

Screw loosening is a widely reported issue after spinal screw fixation and triggers several complications. Biomechanical deterioration initially causes screw loosening. Studies have shown that incomplete insertion of pedicle screws increases the risk of screw breakage by deteriorating the local mechanical environment. However, whether this change has a biomechanical effect on the risk of screw loosening has not been determined. This study conducted comprehensive biomechanical research using polyurethane foam mechanical tests and corresponding numerical simulations to verify this topic. Pedicle screw-fixed polyurethane foam models with screws with four different insertion depths were constructed, and the screw anchoring ability of different models was verified by toggle tests with alternating and constant loads. Moreover, the stress distribution of screw and bone-screw interfaces in different models was computed in corresponding numerical mechanical models. Mechanical tests presented better screw anchoring ability with deeper screw insertion, but parameters presented no significant difference between groups with complete thread insertion. Correspondingly, higher stress values can be recorded in the model without complete thread insertion; the difference in stress values between models with complete thread insertion was relatively slight. Therefore, incomplete thread insertion triggers local stress concentration and the corresponding risk of screw loosening; completely inserting threads could effectively alleviate local stress concentration and result in the prevention of screw loosening.

REACTION OF O-PHENYLENEDIAMINE WITH EPICHLOROHYDRIN AND EVALUATION OF THE PRODUCT AS A RUBBER ANTIAGING AGENT

The epichlorohydrin - o-phenylenediamine reaction product has have obtained. With reverse titration the fact has been proven that the epoxy groups were completely used up to produce the adduct. The Shimadzu FTIR-8400S Fourier spectrometer was used to register the IR spectra. Through IR spectroscopy it was demonstrated that the resulting product is a secondary amine. Thus, epichlorohydrin epoxide groups react with the o-phenylenediamine amino groups. The product has been isolated in the form of a solid crystalline substance having the melting temperature range of 104-106 °С. The rubber mixes based on SKS-30ARKM-15 butadiene-styrene rubber containing sulfur, 2-mercaptobenzthiazole, diphenylguanidine, zinc white, industrial stearin, N-550 carbon black and rubber anti-aging agents at 6.6 mmol/100 g were also studied. The epichlorohydrin - o-phenylenediamine reaction product, N-isopropyl-N'-phenyl-p-phenylenediamine, and 2,2-methylene-bis(4-ethyl-6-tert-butylphenol) were used as the anti-aging agents. A rubber mix containing no anti-aging additives was studied. The rubber mixes have been prepared in LB 320 160/160 rollers, at 45-55 °C. The vulcanization properties of the rubber compounds were tested using Prescott Instruments Rheo-Line MDR rheometer at 160 °C. It was established that the studied adduct has virtually no effect on the vulcanization rate. High values of the difference between the maximum and minimum values of the torque of rubber with the adduct under study indicated a high degree of cross-linking of macromolecules. The mixture has been vulcanized in a 600-600 2E hydraulic vulcanization press at 160 ºC for 15 min. Studies of the properties of vulcanized rubber were carried out in accordance with the standards accepted for the rubber industry. High tensile stress values at given elongations for the rubber containing the product studied have also indicated a high degree of vulcanization. The use of the epichlorohydrin - o-phenylenediamine reaction product in the SKS-30ARKM-15 rubber based compounds has ensured high thermal aging resistance as well as dynamic fatigue resistance.

Evaluation of polymerization shrinkage stress and cuspal strain in natural and typodont teeth.

To evaluate the polymerization shrinkage stress and cuspal strain (CS) generated in an artificial (typodont) and in a natural tooth using different resin composites. Twenty artificial and 20 extracted natural molars were selected. Each tooth was prepared with a 4x4 mm MOD cavity. The natural and typodont teeth were divided into four experimental groups (n=10), according to the resin composite used: Filtek Z100 (3M Oral Care) and Beautifil II LS (Shofu Dental). The cavities were filled using two horizontal increments and the CS (µS) was measured by the strain gauge method. Samples were sectioned into stick-shaped specimens and the bond strength (BS) (MPa) was evaluated using a microtensile BS test. Shrinkage stress and CS were analyzed using 3D finite element analysis. No difference was found between the type of teeth for the CS as shown by the pooled averages: Natural tooth: 541.2 A; Typodont model: 591.4 A. Filtek Z100 CS values were higher than those obtained for Beautifil II LS, regardless of the type of teeth. No statistical difference was found for the BS data. Adhesive failures were more prevalent (79.9%). High shrinkage stress values were observed for Filtek Z100 resin, regardless of tooth type. The CS of typodont teeth showed a shrinkage stress effect, generated during restoration, equivalent to that of natural teeth.

SOIL ERODIBILITY IN AREAS UNDER CITRUS (CITRUS SINENSIS L. OSBECK) AND FOREST IN RONDÔNIA, BRAZIL

Few studies have studied soil erodibility in areas that have undergone conversion processes from native forest to agricultural areas, especially in agricultural frontier regions. The present study aimed to evaluate soil erodibility in areas under citrus (Citrus sinensis L. Osbeck) and forest, using multivariate statistics and geostatistics in areas under different uses in Southern Rondônia, Brazil. A 42 × 30 m grid with regular spacing between sample points of 6 × 6 m was established for the studied native forest and citrus areas at depths of 0.00-0.20 m. At each sampling point, samples with preserved sod structure were collected at the evaluated depth for determination of soil texture and organic carbon, totaling 288 samples in the two studied areas. In the results it was observed that the area cultivated with citrus and under forest presented a greater predisposition of the soil to suffer erosion interril (Kiwepp), the citrus area also presented a greater susceptibility of the soil to suffer erosion in furrows (Krwepp), on the other hand, this area showed high values of critical shear stress, a fact that signals the resistance of the soil to the beginning of the erosive process. On the other hand, the forest area showed a greater predisposition to suffer erosion (K-factor), a fact possibly linked to the high values of silt and sand, which favored the present erodibility conditions.

STRUCTURE FORMATION OF IRON-CONTAINING DISPERSIONS OF ORGANOMONTMORYLONITE

The aim of the work is to study the processes of structure formation of organomontmorillonite in iron-containing dispersions by studying the rheological and colloid-chemical properties of such systems. To modify the surface of montmorillonite, a cationic surface-active substance, a quaternary ammonium salt, hexadecyltriammonium bromide, was used. With the help of X-ray diffraction analysis, we confirmed the penetration of molecules of surface-active substances into the interlayer space of the mineral and its increase to 1.86 nm during the modification mineral surfactant/ cation exchange capacity (S/CEC)=1. The analysis of the results of rheological studies showed that the changes in the characteristics of montmorillonite dispersions depending on the concentration of surfactants are extreme and reach a maximum (6.7 Pa) at the degree of modification of the mineral S/CEC=0.3. The high values of ultimate shear stress confirm the formation of a continuous network between the mineral particles with an "edge–face" orientation. When the surfactant content in the system increases, the ultimate shear stress of the suspension gradually decreases and reaches practically zero values. These results lay the foundation for determining the optimal parameters for the synthesis of iron-containing dispersions based on organomontmorillonite. nZVI was obtained by its reduction on the solid surface of organomodified montmorillonite from a solution of iron(II) sulfate salt. X-ray diffraction data confirmed the fixation of nZVI on the surface of organophilized montmorillonite. Analysis of the results of rheological studies showed that changes in the characteristics of dispersions of iron-containing material based on organomontmorillonite depending on the content of nZVI are extreme and reach a maximum at (6.8 Pa) when the iron content in the sorbent is 0.01 mass fraction in the solid phase of the sorbent. When the content of nZVI is increased to 0.05 mass fraction of the solid phase of the sorbent, it is possible to obtain dispersions with high values of ultimate shear stress (3.3 Pa) and clearly expressed hysteresis loops, which indicates the formation of thixotropic structures and confirms the possibility of its use in permeable reaction barriers. Experimental data confirm that with an increase in the content of nZVI above 0.1 mass fraction in the samples, the ultimate stress and plastic viscosity decrease, which leads to the failure of the suspensions. These results lay foundation for determining the optimal parameters of sorbents synthesis and regulation of their properties by changing the hydrophilic-hydrophobic balance of source systems.

Strength of Composite Transport and Launch Container for Rocket Launch

A transport and launch container for launching rockets made of fiberglass is considered. The main goal of the paper is to calculate the stress state of this container and check the strength conditions. The calculation of the pressures of the combustion products is carried out for several positions of the rocket nozzle in the container. Two cases are considered for the nozzle, which is located: in the middle of the container and at the outlet of the container. The maximum values of the pressure acting on the inner side of the container are observed when the rocket nozzle exits the container. The pressure field is axisymmetric. In view of this, to approximate the pressure field, it is decomposed into a Fourier series along the longitudinal coordinate of the rocket. The stress state of the container is also axisymmetric. In addition, it is also considered for two cases of the nozzle and the container configuration. The finite element method implemented in the ANSYS software complex was used to calculate the stress state. The highest stress values are observed when the nozzle exits the container. As it follows from the finite element calculations, circumferential stresses are the greatest. The strength limit of fiberglass is used to analyze the strength of the container. As can be seen from the calculations, the container meets the strength requirements with a large margin factor.

Assessment of Stress Distribution with 3 Taper Design Preparation of Root Canal Using Finite Element Analysis.

Present research was done to assess stress distribution in three different taper design preparation of root canal with the help of finite element analysis. Lower incisors teeth having single canals that were cleaned and shaped with the help of NeoEndo Flex Titanium (NiTi) rotary file and later three designs were created such as 4%, 6%, and 8% canal preparation taper. Cone beam computed tomography (CBCT) was done for all teeth and subjected to finite element analysis for stresses. The collected data were statistically analyzed. Highest stress was found in the coronal followed by the middle and least in the apical part in all three designs. The highest stress value was found in enamel than dentin (MPa). The highest stress value was found with design 3 (8% taper) followed by designs 2 (6% taper) and 1 (4% taper) for enamel and dentin with either oblique or vertical stress loading. All canals preparation exhibited maximum enamel stress at the coronal load points compared to apical and middle portions. The stress increases with increase in canal tapering.

Evaluation of two treatment concepts of four implants supporting fixed prosthesis in an atrophic maxilla: finite element analysis

BackgroundCurrently, oblique placement of long implants or the use of short implants to circumvent the maxillary sinus area and provide support for fixed prostheses are viable alternatives. The purpose of this study was to compare these two treatment concepts and ascertain which one exhibits superior biomechanical characteristics.MethodsTwo different treatment concept models were constructed. The first one, LT4I, consisting of two mesial vertical implants positioned in lateral incisor regions and two distal tilted implants (45°) situated in second premolar regions of the maxilla. The second model, VS4I, includes two mesial vertical implants in lateral incisor regions and two vertically positioned short implants in second premolar regions. Numerical simulations were conducted under three loading types: firstly, oblique forces upon the molars; secondly, vertical forces upon the molars; thirdly, oblique forces upon the incisors. The maximum principal stress (σmax) and minimum principal stress (σmin) of the bone, as well as von Mises stress of the implants, were calcuated.ResultsUnder oblique loading on the molar, higher stress values in the bone were observed in LT4I group. Under vertical loading on molar, higher stress values in the bone were also observed in LT4I group. Furthermore, little difference was found between the two groups under oblique loading on the incisor.ConclusionBoth treatment concepts can be applicable for edentulous individuals with moderate atrophic maxilla. Compared to tilted implants, short implants can transmit less occlusal force to the supporting tissues.

Integrity Assessment of Stress Corrosion Cracking Susceptibility of Duplex UNS S32205 and Austenitic UNS S31653 Stainless Steel Reinforcements

Herein, the stress corrosion cracking (SCC) susceptibility of duplex (UNS S32205) and austenitic (UNS S31653) stainless steel (SS) reinforcements was evaluated using integrity assessment criteria. Mechanical properties were analyzed and compared by different SCC susceptibility factors. The integrity assessment was conducted applying Cosenza, Creazza, and Ortega ductility criteria, following three different standards (ACI 318-19, ASTM A615, and FIB). A conventional carbon steel (UNS G10080) reinforcement was also evaluated for comparative purposes, whose high residual stress value (&gt;280 MPa) promoted a high corrosion growth rate. Duplex UNS S32205 SS grade showed a significant decrease in elongation, leading to failure after ductility assessment at high chloride concentrations. Fractographic analysis of both SS grades, duplex and austenitic, revealed less than 40% brittle areas at 8 wt.% Cl−, while UNS G10080 had over 85% at 4 wt.% Cl−.

Fully ceramic versus steel gears: Potential, feasibility and challenges

The most common gear strength calculations performed in accordance with ISO/TC 60/SC 2 include surface durability and root bending strength. Typical geared power transmissions are characterized by high Hertzian contact stresses (surface durability) on the flanks – frequently in the order of 103 MPa – versus almost half an order magnitude lower first principal stresses on the tooth root (tooth bending strength). Therefore, the use of high strength special steel alloys is almost mandatory, especially in high-end applications, mainly to withstand the high contact stress values. Ceramic materials are typically characterized by high compressive strength versus very low flexural strength that at first glance makes them inefficient for gear transmissions since they are unlikely to withstand the tensile root stresses. Nevertheless, ceramic materials possess a number of advantages that makes them potential candidates for geared transmissions, such as their exceptional thermal properties, their low density (weight), their excellent wear characteristics and limited lubrication demands. The present work investigates the main challenges of using high-end ceramic gears and attempts to provide an insight on defining the design envelope of such gears to counter the main disadvantages. The increase of the normal pressure angle beyond the 25° limit set by ISO 6336 is primarily investigated, since in minimizes the tensile tooth root stresses, while also increasing the curvature of the contact surfaces without greatly increasing Hertzian stresses. Comparative assessment of the performance of fully ceramic gear designs versus their conventional steel counterparts is performed through quasi-static FEA simulations to set the basic design requirements for such gears and to promote further investigation of the feasibility of their usage in high power density applications.

Stress distribution of four implant supported overdentures with tilted standard-sized implants and mini implants.

The goal of the current study is to evaluate the stress distribution when tilted implants and mini-implants are used to support a mandibular overdenture. Three-dimensional (3D) finite element models of mandibular overdentures were established using four, axial, standard-sized implants (SA model), four standard-sized implants with the mesial ones axial and the distal ones tilted (ST model) and four mini-implants (MA model) with Locator attachments. On each model, a 100 N load was applied to the overdenture in four different directions; bilateral vertical, unilateral vertical and oblique load on the posterior region, and a vertical load on the incisors. The stresses distributed at the peri-implant bone, implants, the prosthetic components, and the overdentures were evaluated. Non-axial posterior loading caused higher stress values in the implant and the prosthetic component than axial posterior loading. Lower stress values of the implant and the prosthetic component were observed in the ST model than SA model. The stress distribution in the overdenture at posterior loads were mostly observed around the implants. Less prosthetic complications may be expected when the treatment option in the ST model is used. Fatigue fractures may occur around the implants in the overdentures, precautions are advised.

Pengaruh Variasi Gerakan Elektroda Pada Pengelasan Smaw Terhadap Uji Kekuatan Bending Baja ST 42

This study aims to determine the effect of straight groove, zigzag groove, and U pattern groove movement on the hardness and mechanical properties of the material in ST42 steel welding. The welding method used is shielded metal arc welding (SMAW) with a current strength of 100 Amperes. The test results show that the movement of the straight groove electrode gives the highest stress value in the bending test with an average of 1,168 MPa. The zig-zag groove electrode movement gave an average stress value of 1.127 Mpa, while the U pattern groove electrode movement gave an average stress value of 1.905 MPa. Microstructural testing showed that all electrode movements produced pearlite and ferrite phases, but straight groove electrode movements had more pearlite phases than the other movements. In addition, the zig-zag groove electrode flow and U pattern. This study provides a better understanding of the effect of electrode movement on the quality of welded joints, as well as providing important information in the development of industrial welding techniques.

Effect of Pin Holes Location of Unicompartmental Knee Arthroplasty on Postoperative Tibial Plateau Mechanical Properties

The purpose of this study is to explore the biomechanical characteristics of the tibia after unicompartmental knee arthroplasty with different distributions of two-pin holes, and to optimize the two-pin holes scheme to reduce the risk of tibial fractures after unicompartmental knee arthroplasty. Lower limbs model is segmented and reconstructed from computed tomography images. Four combinations of two pin holes created for tibial cutting guide placement are simulated with finite element analysis. In the third mode, the positioning hole at the proximal medial edge of the tibial plateau has the highest stress value, and the position of the positioning hole near the medial edge of the proximal tibial plateau appears stress concentration. The present study revealed that placing tibial cutting guide holding pins centrally would lower the risks of periprosthetic fracture of the medial tibial plateau.

Biomechanical effects of different materials for an occlusal device on implant-supported rehabilitation in a tooth clenching situation: A 3D finite element analysis.

The purpose of this 3D finite element analysis was to evaluate the biomechanical effects of different materials used to fabricate occlusal devices to achieve stress distribution in simulated abutment screws, dental implants, and peri-implant bone tissue in individuals who clench their teeth. Eight 3D models simulated a posterior maxillary bone block with three external hexagon implants (Ø4.0×7.0mm) supporting a 3-unit screw-retained metal-ceramic prosthesis with different crown connection (splinting), and the use of an occlusal device (OD). The OD was modeled to be 2-mm thick. ANSYS 19.2 software was used to generate the finite-element models in the pre-and post-processing phases. Simulated abutment screws and dental implants were evaluated by von Mises stress maps, and simulated bone was evaluated by maximum principal stress and microstrain maps by using a finite element software program. The highest stress values in the dental implants and screws were observed in single crowns without OD (M1). Furthermore, the highest stress values and bone tissue strain were found in single crowns without OD (M1). The simulated material for the OD did not cause many discrepancies in terms of the stress magnitude in the simulated dental implant and abutment screw for both single and splinted crowns; however, more rigid materials exhibited lower stress values. The use of OD was effective in reducing stress in the simulated implants and abutment screws and stress and strain in the simulated bone tissue. The material used to simulate the OD influenced the biomechanical behavior of implant-supported fixed prostheses, whereas splints with rigid materials such as PEEK and PMMA exhibited better biomechanical behavior.

Present-day in-situ stress prediction in the Duvernay shale of Simonette Block, Western Canada Sedimentary Basin

The Duvernay Formation of Simonette Block is rich in shale oil and gas resources. The present-day in-situ stress field is a crucial parameter during the exploration and development in this block, a better understanding of which can assist with drilling and completion engineering, fracturing stimulation, and well deployment. In this study, the present-day in-situ stress in the Duvernay shale is predicted and analyzed based on well calculations and geomechanical modeling. The findings indicate that, I, NE-SW-trending is the dominant S Hmax orientation. The S Hmax and S hmin are the maximum and minimum principal stress, indicating that the Duvernay shale of Simonette Block is under a strike-slip faulting stress regime. II, The present-day in-situ stress in the Duvernay shale is heterogeneously distributed, which is controlled by lithology difference, fault development, and distribution. High stress values in the upper shale member D layer are mainly in the northwestern and central parts of Simonette Block. III, The present-day differential stress in the Duvernay shale mainly ranges from 15 MPa to 30 MPa. Bedding-parallel fractures are relatively developed, aiding in the creation of complex fracture networks. The results are expected to offer geological references for further development of shale oil and gas in the Simonette Block.

Computer aided analysis of biomechanical performance of schanz screw with different additive manufacturing materials used in pertrochanteric fixator on an intertrochanteric femoral fracture (corrosion resistance approach).

This study examines the use of computer-aided analysis to evaluate the biomechanical performance of Schanz screws made from different additive manufacturing materials (Ti6Al4V, 316 L, Inconel 625, and Inconel 718) in a pertrochanteric fixator for the treatment of intertrochanteric femoral fractures. Intertrochanteric fractures (ITFs) are severe traumas often seen in the elderly population and can lead to serious consequences. The primary objective of ITF surgery is to provide stability and allow for early ambulation and rehabilitation. The Pertrochanteric Fixator is a surgical implant used to treat hip fractures near the greater trochanter, and is attached to the femur with screws. The procedure is performed under general anesthesia and typically takes 1-2 h. Possible complications include infection, nerve injury, and hardware failure. The aim of this study is to evaluate the biomechanical performance of Schanz screw using computer-aided analysis, comparing the effects of various additive manufacturing materials including Ti6Al4V, 316 L, Inconel 625 and Inconel 718 in a pertrochanteric fixator for intertrochanteric femoral fractures. Additionally, this study will also consider the corrosion resistance of these materials to ensure long-term durability and effectiveness in a clinical setting. The stress values mentioned for the implant materials are as follows. Ti6Al4V: 153.33 MPa, 316 L: 180.98 MPa, Inconel 625: 158.94 MPa, Inconel 718: 148.91 MPa. Higher stress values indicate a greater load transfer to the bone, which can potentially lead to stress shielding. Stress shielding occurs when an implant bears a significant portion of the load that should be transferred to the bone. This reduced stress at the fracture site can prevent the healing process, as bones require adequate stress levels for optimal remodeling and regeneration.