Testing Machine Research Articles

Design and characterization of high-performance energetic hydrogels with enhanced mechanical and explosive properties

Polymeric hydrogels, known for their excellent mechanical properties and pre-cross-linking flowability, provide a promising solution for recycling waste propellants, ensuring safety and maintaining explosive performance. This study developed a double cross-linked network energetic hydrogel that effectively combines mechanical strength with explosive capabilities. Using a Ford 4 Cup, temperature data logger, universal testing machine, and detonation performance tests, we examined the impacts of kinematic viscosity, cross-linking time, compressive strength, and explosive properties. The optimal kinematic viscosity for stabilizing hollow glass microspheres (GM) was found to be 129.7 mm2/s. Cross-linking time was negatively correlated with initiator, catalyst levels, and reaction temperature, but positively correlated with retarder content. Compressive strength increased with acrylamide (AM) content and showed an initial rise before decreasing with N,N′-methylenebisacrylamide (MBAA) content and reaction temperature. The maximum compressive strength was achieved with 5% MBAA (of AM mass fraction) at 40 °C. Detonation velocity and steel plate damage decreased with increasing AM content and initially increased then decreased with GM content. A balance of mechanical and explosive properties was achieved with 6% AM and 4% GM, resulting in a detonation velocity of 4536 m/s. This hydrogel shows significant potential for waste munitions management.

Influence of clinical risk factors for preterm premature rupture of membranes (PPROM) on the elastic strength of fetal membranes at term: A prospective study.

Premature rupture of membranes (PROM) before 37 weeks of gestation is a common obstetrical event, whose pathophysiology is still poorly understood. Our objective was to study the mechanical strength of fetal membranes in women with a clinical risk factor for preterm premature rupture of membranes (PPROM). We included, in a prospective, descriptive, single-center study, patients scheduled for cesarean section at term (≥ 37 weeks of gestation). For each patient, we performed uniaxial tensile tests on fetal membranes with a universal testing machine equipped with a force sensor (EZ20®, Lloyds), allowing the recording of an applied force/time curve. We collected maximum force (Fmax), maximum stress (σMax), and Young's modulus of elasticity. The thickness of each membrane sample was also measured. We compared the values obtained according to certain clinical risk factors for PPROM such as age, body mass index, gravidity, parity, a history of PPROM or preterm birth, smoking, gestational diabetes, geographic origin, and socioeconomic level. We analyzed 31 patients and found no association between the studied risk factors and σMax. Fmax was lower in primiparous patients (p = 0.02) but increased with patient parity (p = 0.005). Gestational diabetes was associated with a higher Fmax (p = 0.033) and sub-Saharan geographical origin with a greater thickness (p = 0.0043). As membrane thickness increased, σMax (p = 0.009) and Young's modulus decreased (p = 0.037). Primiparous patients have lower membrane mechanical strength than patients who have had one or more deliveries. Mechanically, the thicker membranes are less rigid and less resistant.

Metamodel-based Hybrid Parametric Optimization with Static Prototype Validation for a Six-Axle Wheel Load Cell Design

The accurate measurement of forces and torques acting on a vehicle’s chassis, originating from wheel-pavement interactions, is essential for optimizing suspension systems, axles, and other structural components. A critical challenge in optimizing wheel load cell (WLC) design is to enhance sensitivity without compromising mechanical robustness. To address this question, this study developed a six-axis load cell designed to decouple force and torque measurements, achieving high sensitivity and reliability. The objective was to design an optimized WLC for multi-axis force measurement by maximizing sensitivity through a metamodel-based hybrid optimization framework. The methodology began with a fractional factorial Design of Experiments (DOE) to identify key parameters affecting load cell sensitivity and to define the optimization search space. This was followed by a dual-step parametric optimization process, utilizing the finite element method (FEM) to evaluate load cell performance and an inner-point optimization algorithm for convergence. After completing the DOE and FEM stages, the load cell was physically constructed and calibrated using a universal testing machine MTS 810, where experimental data closely matched simulation results, validating the design’s effectiveness. The main findings indicate that the optimized load cell can reliably measure six components, with a sensitivity increase of 14% compared to conventional designs. Numerical results from FEM analyses showed stress levels at 215 MPa, displacements around 0.16 mm, and a first-mode vibration frequency of 1351 Hz, meeting all structural integrity and performance requirements. Calibration confirmed minimal cross-talk effects, supporting the robustness of the final design. The developed load cell met optimal design criteria, showing substantial improvements in sensitivity and accuracy over existing designs, with potential applications in automotive, aerospace, and engineering testing.

Development of Objective Test Functions for Modeling and Sensitivity Analysis of the Mechanical Behaviour of Aluminum-Agro-Marine Waste Composites.

Abstract Aluminum-based composites reinforced with agro-marine waste materials present an eco-friendly, cost-effective solution for industries needing lightweight and durable materials. This study develops and evaluates the mechanical properties of aluminum (AA6061) composites reinforced with plantain stem ash, eucalyptus wood ash, and periwinkle shell powder for potential aerospace, automotive, and marine applications. Composite samples were prepared according to ASTM standards for tensile, compressive, flexural, wear, and fatigue tests. Objective Test Functions (OTFs) were derived using physical modeling and sensitivity analysis to filter impactful variables. Testing was conducted using universal testing machines, and wear/friction tests followed ASTM G99 guidelines. The physical models showed strong correlations (adjusted R²: 0.9033–1.0000). Measured properties included tensile strength (1907.46–2000.05 Pa), compressive strength (30.33–215.14 Pa), flexural strength (412.72–556.42 N-m²), wear rate (55.01–63.27 m³/m), coefficient of friction (0.102), and fatigue cycle (13.81–27.63 cycles). Except for the coefficient of friction, all results were consistent with the developed OTFs, confirming the material's structural integrity. The composites displayed favourable properties for use in aerospace, automotive, and marine industries, offering strength, lightweight characteristics, and corrosion resistance. The OTFs validated the material's performance, making it a viable alternative to conventional materials. Consequently, aluminum-agro-marine waste composites demonstrate excellent mechanical properties, with high potential for industrial applications.

Mechanical, machinability and water absorption properties of novel kenaf fiber, glass fiber and graphene composites reinforced with epoxy

This paper aims to fabricate a novel kenaf fiber, glass fiber, graphene composite reinforced with epoxy, and to study its water absorption, mechanical and machining properties. Natural fiber composites seek numerous applications nowadays due to its high strength is to weight ratio, high impact resistance, thermal stability, and recyclability. The literature study on natural fiber composites indicates lack of research on Kenaf fibers reinforced with E-glass fibers in conjunction with 0.5% and 1.0% of graphene. Hence, this research focuses on Kenaf fiber with percentage composition of graphene was varied as 0.5%, and 1.0%, by weight of the holding matrix and with/without incorporation of glass fiber. Suitable surface modifications were done by treating natural fibres by 0.5% NaOH for better adhesion of fibre and epoxy resin. Sonication and Cetyl trimethyl ammonium bromide (CTAB) treatments were also done to realize the fine scattering of graphene in the epoxy matrix in order to achieve better mechanical behaviour. Moulds were prepared as per D-638 ASTM standards. The treated fibres were then arranged in the mould by the conventional hand layup technique. The main objectives of this study are to conduct tensile, flexural, Impact, water absorption, machinability, and FTIR test. Result shows that the incorporation of graphene in natural fiber composites showed an increase in tensile strength, flexural strength, and water absorption properties by 27.7%, 53%, and 15% on average, respectively. The composites used in this research find their use in potential applications such as defence, biomedical aids, automobiles, packaging, actuators, etc. These often generate great interest, whenever there is a demand for fabricating lightweight and high strength material.

A Study of the Optimization of FDM Parameters for the Manufacture of Compression Specimens from Recycled PETG in the Context of the Transition to the Circular Economy

The current paper presents the results of a research on the optimization of Fused Deposition Modeling (FDM) parameters, namely the height of the deposited layer in one pass, Lh, and the filling percentage, Id, with the purpose of manufacturing compression specimens from recycled Polyethylene Terephthalate Glycol (rPETG), and thus, aiming the transition to circular economy. A total of 45 compression specimens were manufactured from rPETG on the Anycubic 4Max Pro 3D printer with variable parameters Lh = 0.10 mm, 0.15 mm, 0.20 mm, and Id = 50%, 75%, 100%. All 45 specimens were tested in compression on the Barrus White 20 kN universal testing machine. The considered variable parameters influence the Compressive Strength (CS) of the specimens, with Id being the parameter with overwhelming influence.

Innovative surface engineering of sustainable polymers: Toward green and high-performance materials

The development of sustainable polymers is critical to the progression of greener manufacturing processes, especially for the additive manufacturing technologies of fused deposition modeling (FDM). The study aims to explore potential application surface engineering techniques that enhance the performance of these sustainable polymers within the context of FDM. Various surface modification methods, such as plasma treatment, chemical etching, and UV irradiation, were utilized on biodegradable and recycled polymers, with the treatment process conducted under controlled conditions. Mechanical testing was done using a Tinius Olsen universal testing machine, with surface morphology analyzed through scanning electron microscopy. The outcome indicated that the tensile strength of polylactic acid improved by 15% with plasma treatment, while the thermal stability of recycled polyethylene terephthalate improved by 12% with chemical etching. Surface engineering developments on various techniques will be reviewed, particularly in optimizing them within FDM processes for different types of polymers. Different surface modifications will be compared here, analyzing aspects such as adhesion, endurance, and more overall performance. This comparison provides a fundamental outlook into the relationship between surface treatment and polymer performance, paving the way for optimization of FDM processes in sustaining material applications. These findings serve as further guidance toward making additive manufacturing much more sustainable and efficient through advanced surface engineering. The numerical improvement of material properties observed in the study will aid in further endeavors towards achieving sustainability and efficiency in additive manufacturing.

Cyclic and torsional fatigue resistance of two replicalike and original brand reciprocating system

The aim of this study was to evaluate the cyclic and torsional fatigue resistance of two replicalike in comparison of the original brand reciprocating system. Material and methods: A total of 60 reciprocating instruments were used to perform the cyclic and torsional fatigue test of following systems: Reciproc Blue 25.08 (RB 25.08), Only One File Blue (OFB 25.08) and RC Blue 25.08 (RCB 25.08) (n=20). The cyclic fatigue test was performed using an artificial stainless steel canal with 60º angle of curvature and a 5-mm radius of curvature. The instruments were activated until failure occurred. The time to failure (TF) and number of Cycles to failure (NCF) were evaluated. The torsional test was performed following the ISO 3630-1. Three millimeters of the instrument tip was fastened to a small load cell and the maximum torsional strength and angular deflection were recorded using the torsion testing machine software. The fractured surface of each instrument was assessed by scanning electron microscopy (SEM). The data were analyzed using one-way analysis of variance ANOVA and Tukey’s test for Multiple comparisons at a significance level of 5%. Results: The cyclic fatigue tests demonstrated that OFB 25.08 had the highest TF and NCF than among the groups (P<0.05). RCB 25.08 exhibited lowest TF and NCF (P>0.05). Regarding the torsional test, the RCB 25.08 and OFB 25.08 had the highest torque than the other groups (P<0.05). Additionally, RB 25.08 and OFB 25.08 exhibited highest angular deflection values than the other groups (P><0.05). Conclusion: The OFB 25.08 demonstrated highest TF and NCF than the instruments tested. The RCB 25.08 exhibited lowest cyclic fatigue resistance and angular deflection.> P<0.05). RCB 25.08 exhibited lowest TF and NCF (P>0.05). Regarding the torsional test, the RCB 25.08 and OFB 25.08 had the highest torque than the other groups (P<0.05). Additionally, RB 25.08 and OFB 25.08 exhibited highest angular deflection values than the other groups (P><0.05). Conclusion: The OFB 25.08 demonstrated highest TF and NCF than the instruments tested. The RCB 25.08 exhibited lowest cyclic fatigue resistance and angular deflection.> P<0.05). Conclusion: The OFB 25.08 demonstrated highest TF and NCF than the instruments tested. The RCB 25.08 exhibited lowest cyclic fatigue resistance and angular deflection.

Effect of squeeze motion on the tribo-performances of molybdenum disulfide powder lubricated textured cemented carbide specimens

Purpose This study aims to improve the lubrication performance of molybdenum disulfide powders at textured surface of cemented carbide materials, a squeeze motion of vibration assistance method was introduced and investigated. Design/methodology/approach Surface texture was fabricated on YT15 cemented carbide samples using a laser marking machine. After that, a tribological experiment was carried out on a self-built friction testing machine under different amplitude and frequency of squeeze motion conditions. Moreover, a simulation model was also established to verify the principle of squeeze motion on the lubrication performance improving of MoS2 particles at textured interfaces. Findings Analysis results indicated that surface texture on test sample can increase the storage ability of solid lubrication particles, and the lubrication film at the contact interface is more easily formed due to the reciprocating action. Squeeze motion can improve the storage ability of it due to an intermittent contact, which provides an opportunity for MoS2 particles infiltration, and then a more uniform distribution and load-bearing properties of force chain are also established and formed simultaneously. Thus, a better tribological performance at the contact interface is obtained. Originality/value The main contribution of this work is to provide a reference for the molybdenum disulfide powder lubrication with textured surface of cemented carbide materials. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2024-0166/

Effects of aging on the tensile strength and surface condition of orthodontic aligners: a comparative study of five models.

The objective of this study is to determine the effect of aging on tensile strength and surface condition of orthodontic aligners on days 0, 1, 5, 7, 10, and 14. The total sample of 80 aligners included five brands (Accusmile®, Angel®, GRAPHY®, Invisalign® and Suresmile®) were placed in a thermocycler to imitate the temperature variations of the oral cavity and accelerate aging for 50, 250, 350, 500, and 700 cycles. The mechanical tensile properties (Young's modulus E, yield strength YS, maximum elastic stress MES, Ultimate Tensile Strength UTS, and maximum stress MS) were measured by Universal Testing Machine at a rate of 5 mm of deformation per minute for 4 minutes. Microscopic observations were made under a voltage of 10 kV at magnifications times 50, 250, 500, 1000, and 2500 after cleaning with ethanol and ultrasound then metallization with gold. YS and MES of Angel® aligners are statistically reduced after five days of aging (P = .003). Aligners from the most rigid to the most flexible are (decreasing E): Accusmile® > GRAPHY® > Suresmile® > Invisalign® > Angel®. Surface conditions also deteriorated with aging (appearance of scratches, porosity, cracks, etc.). GRAPHY® aligners are more heterogeneous and weaker than others. In vitro study. Mechanical properties of Accusmile®, GRAPHY®, Invisalign®, and Suresmile® were not affected by aging. YS and MES were reduced from day 5 for Angel® aligners. Surface conditions are also altered by aging.

Development of Polyvinyl Alcohol/Polyethylene Glycol Copolymer-based Orodispersible Films Loaded with Entecavir: Formulation and In vitro Characterization.

The aim of the study is to prepare entecavir (ETV)-loaded orodispersible films (ODFs) using polyvinyl alcohol (PVA)/polyethylene glycol (PEG) graft copolymer (Kollicoat® IR) as a film-forming agent, and further to evaluate the dissolution rate, mechanical and physicochemical properties of films. ETV-ODFs were prepared by a solvent casting method. The amount of film-forming agent, plasticizer, and disintegrating agent was optimized in terms of the appearance, thickness, disintegration time and mechanical properties of ODFs. The compatibility between the drug and each excipient was conducted under high temperature (60 °C), high humidity (RH 92.5%), and strong light (4500 Lx) for 10 days. The dissolution study of optimal ODFs compared with the original commercial tablet (Baraclude®) was performed using a paddle method in pH 1.0, pH 4.5, pH 6.8, and pH 7.4 media at 37 °C. The morphology of ODFs was observed via scanning electron microscopy (SEM). The mechanical properties such as tensile strength (TS), elastic modulus (EM), and percentage elongation (E%) of ODFs were evaluated using the universal testing machine. The physicochemical properties of ODFs were investigated using X-ray diffraction (XRD), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FT-IR). The related substances were less than 0.5% under high temperature, high humidity, and strong light for 10 days when ETV was mixed with excipients. The optimal formulation of ODFs was set as the quality ratio of Kollicoat® IR, glycerol, sodium alginate (ALG-Na): TiO2: MCC+CMC-Na: ETV was 60:9:12:1:1:1. The drug-loaded ODFs were white and translucent with excellent stripping property. The thickness, disintegration time, EM, TS, and E% were 103.33±7.02 μm, 25.31±1.95 s, 25.34±8.69 Mpa, 2.14±0.26 Mpa, and 65.45±19.41 %, respectively. The cumulative drug release from ODFs was more than 90% in four different media at 10 min. The SEM showed that the drug was highly dispersible in ODFs, and the XRD, DSC, and FT-IR results showed that there occurred some interactions between the drug and excipients. In conclusion, the developed ETV-loaded ODFs showed relatively short disintegration time, rapid drug dissolution, and excellent mechanical properties. This might be an alternative to conventional ETV Tablets for the treatment of chronic hepatitis B.

Mechanical property and cracking mechanism of Cr-coated Zr alloy under tensile and compressive loading

Cr coatings are considered as the most promising candidate materials for accident-tolerant fuel cladding coatings. In combination with optical microscopy, focus ion beam, energy dispersive spectrum and universal testing machine, the effect of Cr coating on hoop tensile and compressive mechanical properties of Zr alloy was studied and the underlying cracking failure mechanism of Cr coating was revealed. The results indicate that Cr coating slightly increases tensile/compressive yield strength and tensile strength compared with those of uncoated Zr alloy. This is attributed to high hardness/elastic modulus of Cr coating. Interrupted hoop tensile and compressive tests show that Cr coating cracking concentrates in the range of 0-30°. Further, crack initiation of the coating occurs either at the surface or at the interface between Cr coating and the matrix. Compared with the former, the latter is dominant cracking mode, irrespective of tensile and compressive loading. In lights of the advanced microstructural analysis, one possible reason, i.e., the existence of nano-scaled Al-enriched loose layer between the interface, in which nano-cracks and voids exist, is proposed to explain the interfacial cracking. The result indicates that the optimization of the interfaces can improve the resistance of coating failure. In addition, crystallographic study demonstrates that the crack propagation in the Cr coating is along the high-angle grain boundaries with the misorientation of 50°.

A study on influence of sintering temperature, diameter and volume fraction of metal hollow spheres on the mechanical properties of metal hollow spheres composites

The structural parameters (the sintering temperature, diameter, and volume fraction of the hollow spheres) have a considerable influence on the mechanical properties of metal hollow sphere composites (MHSCs). Hence, the influence laws of the structural parameters on the mechanical properties of MHSCs possess certain research significance. To obtain these laws, MHSCs with different structural parameters were fabricated using a pressure casting method. Subsequently, the density of the MHSCs was determined through the direct measurement method. Meanwhile, X-ray diffraction and scanning electron microscopy were employed to conduct in-depth analyses of the phase composition and microstructure of the MHSCs. Additionally, the compression performance of the MHSCs was measured with the assistance of a universal mechanical testing machine. The analysis of the microstructure and phase composition results revealed that MHSCs consisted of γ-Fe, Al, Si, Fe₂Al₇Si, Fe₂Al₄Si, and Al₈Si₆Mg₃Fe phases, with the transition layer composed of the Fe₂Al₇Si phase. The results of the compression performance indicated that the compression performance of MHSCs increased with the rise of the sintering temperature and decreased with the increase of the volume fraction. However, as the diameter of MHS increased, the yield strength of MHSCs declined while the deformation strength of MHSCs increased. When the diameter of the MHSs was 2.55mm and the volume fraction was 40%, the compression performance of the MHSCs reached its optimum. At that point, the yield strength was 113.65±3.37 Mpa, and the average deformation strength was 81.26±5.45 Mpa.

Can flowable short-fiber-reinforced resins achieve a strong adhesion to bioceramics?

This study compared the microshear bond strength (μSBS) of four calcium silicate-based cements (CSCs), TheraCal PT (TPT), TheraCal LC (TLC), Biodentine (BD), and Dia-Root Bio MTA (DR), with a short fiber-reinforced composite resin (SFRC). Forty cylindrical acrylic blocks were used, each with a center hole (diameter 5 mm, depth 2 mm). CSCs were placed in the holes (n = 10/group), and the blocks were incubated for 48 h. G-Premio BOND, a self-etching adhesive, was applied to the CSCs surfaces using a micro-applicator for 10 s and then air-dried for 5 s, followed by light curing for 20 s. SFRC materials placed in cylindrical polyethylene capsules (diameter 2 mm, height 2 mm) were polymerized for 20 s and placed over the CSCs. The samples were then incubated at 37°C and 100% humidity for 24 h, and their μSBSs were tested using an "Instron Universal Testing Machine." Data were statistically analyzed using chi-square and Kruskal-Wallis tests. Statistically significant differences were observed between the tested CSCs. The μSBS of TPT (45.17 ± 4.56 MPa) was significantly higher (p < .05) than that of the other materials: BD, TLC, and DR had μSBSs of 29.18 ± 2.86 MPa (p < .05), 23.86 ± 2.84 MPa (p > .05), and 18.08 ± 2.69 MPa (p < .05), respectively. Considering the importance of bond strength for CSC sealing with restorative material, using SFRC over CSC was promising for improving the μSBS, adhesion, and sealing of the material. RESEARCH HIGHLIGHTS: Adhesion is critical to the success of vital pulp restorations. To achieve strong adhesion, the bioceramic material and the resin composite to which it is bonded are very important. In our study, short fiber-reinforced composite resin, which is gaining popularity, was used and found to be a promising material for improved adhesion.

Study on high temperature tensile constitutive behavior and deformation mechanism of Ti-47.5Al-2.5 V-1.0Cr-0.2Zr alloy

The high temperature tensile test of Ti-47.5Al-2.5 V-1.0Cr-0.2Zr alloy was carried out by electronic universal testing machine under the condition of 750–900 °C/10−5–10−3 s−1. The hot tensile stress-strain curves were analyzed, and the constitutive model under hot tensile conditions was established. The microstructure transformation rule and deformation mechanism during tensile process were determined. The results show that the hot tensile curve is longer in the steady-state flow stage corresponding to lower strain rate and higher tensile temperature, the true stress declines and the elongation at break increases. The constitutive equation was established based on the tensile curve data, and the corresponding thermal activation energy was 310.3 kJ/mol. As the rise of tensile temperature and the decline of strain rate, the proportion about cross-layer fracture in the tensile fracture morphology decreases, the number of dimples increases, more lamellar structures change into recrystallized structures, and the softening effect of the alloy is more obvious. The dislocation deformation mechanism mainly includes the existence of dislocation slip and climb, dislocation intersection and dislocation ring or dislocation network formation. Twinning deformation is also another important mechanism of high temperature tensile deformation of TiAl alloy. Twins are formed in parallel with each other, so that the deformation can be further carried out. The dislocations and twins in the deformed microstructure will provide nucleation conditions for recrystallized grains. The dynamic recrystallization(DRX) grains are preferentially formed around the grain boundary and the vicinity of dislocation and twin is also preferred nucleation site for DRX. The DRX behavior is the main softening mechanism, and DRX size and volume fraction corresponding to lower tensile rate and higher tensile temperature are larger.

Polyelectrolyte complex membranes for zinc-ion cathode by polymerization of polyaniline

Although lithium batteries dominate the rechargeable battery market, concern over safety and material supply have motivated scientists to develop non-lithium-based alternative such as zinc-ion batteries (ZIBs). This work focuses on the development of polyelectrolyte complex-based cathode for ZIBs using a mild aqueous electrolyte such as ZnCl2 instead of KOH and to be further developed into wearable electronics. Composite polyelectrolyte complex electrodes with carbon black and polyaniline (PANI), or manganese oxide (MnO2) as active materials were prepared. The membranes were then further modified by electropolymerization of PANI to enhance the battery performance. Results show that electropolymerization leads to a threefold increase in ZIB performance with increased current density, power density, and specific energy capacity. Zinc chloride (ZnCl2; 1 m) was used as a mild electrolyte instead of potassium chloride (KOH; 6 m) leading to a reduced performance yet allowing for potential use in skin contact and wearable electronics. All the membranes were assembled into ZIB and tested using the battery testing machine. Scanning electron microscopy was used to observe the morphology of the electropolymerized PANI while attenuated total reflection Fourier transform infrared spectroscopy was used to confirm the chemical nature of PANI.

SDN-Driven Security Framework for DDOS Attack Detection and Mitigation

The rising complexity and persistence of Distributed Denial of Service (DDoS) attacks, particularly low-rate variants, present significant challenges in detection and mitigation within Software-Defined Networking (SDN) environments. Existing detection systems often flood networks with alerts, burdening security personnel and delaying timely mitigation. Furthermore, many solutions are designed and tested in simulated conditions, limiting their real-world applicability. To address these challenges, we propose an SDN-based security framework enhanced with automated monitoring, detection, and mitigation capabilities, optimized for slow-rate DDoS attacks. Our framework was rigorously evaluated on a physical testbed, achieving mitigation efficiencies between 91.66% and 100% under varied attack conditions, thus proving its robustness in practical settings. Additionally, we introduce the SDN-SlowRate-DDoS dataset, designed to assist researchers and industry professionals in developing and testing intrusion detection solutions in more realistic scenarios. To further improve DDoS defense in SDN, we incorporate an ensemble online machine learning model that dynamically adapts to evolving attack patterns, enhancing accuracy across attack types and outperforming traditional models with a detection rate of 99.2% on benchmark datasets. This dual approach leverages both real-world testing and adaptive machine learning, advancing proactive DDoS threat management in SDN environments

Characteristics of Chitosan Gelatine Limestone-Based Carbonate Hydroxyapatite Composite Scaffold After Crosslinking

Bone damage is one of the most common cases in dentistry. Tissue engineering is advancing in biotechnology to aid bone regeneration using scaffolds. Scaffolds need to be biocompatible, bioactive, and bioresorbable. Purpose: Analyzing the characteristics of scaffold C-G:CHA after crosslinking with 0.25% glutaraldehyde. Methods: The scaffold is synthesized from C–G:CHA in ratios of 40:60, 30:70, and 20:80 (w/w) using a freeze-drying technique and crosslinked with 0.25% glutaraldehyde. Compressive strengths are tested with a Universal Testing Machine Mini Autograph. FTIR, XRD, and SEM EDX were used to identify the most optimal base of each ratio. Data are analyzed with a one-way ANOVA parametric test. Results: The FTIR test showed that adding 0.25% glutaraldehyde formed a new chemical group. The XRD test indicated the use of 0.25% glutaraldehyde as a crosslinking agent contributed to the scaffold having an amorphous form. The SEM test results of the porosity of the C-G:CHA were 88.41% to 91.14%. After crosslinking the porosities slightly decreased. The EDX analysis showed that the Ca/P ratio in the C-G:CHA scaffold is 1.79 to 2.07. The average compressive strength of the C-G:CHA scaffold increases after being crosslinked with glutaraldehyde. Conclusion: Scaffold C-G:CHA crosslinked with 0.25% glutaraldehyde effective to increase compressive strength. The 30:70 ratio is ideal because it has a Ca/P ratio and average pore size closest to bone.

Prototype of small-scale test machine for vibration measurement on bearings

Repetitive movements of shaft in bearings over time intervals generate vibrations. The aim of this research is to build the prototype of small scale of machine to measure the vibration values of bearing due to spinning shaft using an accelerometer and Arduino sensor device. The method used is to build a device of miniature rotating machines which was used to simulate machine vibrations. The ADXL345 accelerometer measured the magnitudes of vibration that occurs on the rotating shaft. Arduino Uno analyzed data from ADXL345. The amplitude, speed, acceleration and frequency values were measured according to rotation values. It was found the largest amplitude, speed, acceleration and frequency values were obtained at the radial point Y1 position.

Development of polymeric composite scaffolds for defective bone repair and regeneration

Bones are vital components of the body that provide soft internal organs and tissues with structure, motion, and safety. Damage to bones can make life challenging. In repairing and regenerating damaged bone, polymeric composite materials significantly contribute to bone tissue engineering. In this article, we described developing porous scaffolds using the freeze-drying process from sodium alginate (SA), polyvinyl alcohol (PVA), and graphene oxide (GO) incorporated with zinc (Zn). These scaffolds were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and universal testing machine (UTM) to investigate their structural analysis, surface morphology, and mechanical behavior, respectively. These scaffolds also exhibited less swelling in phosphate buffer saline (34.73–64.27%) than in aqueous media (42.36–75.92%) with controlled degradation. These scaffolds have potential biomineralization activities, hemocompatibility, and antibacterial activities, which were increased by increasing the Zn amount. All the scaffolds have biocompatibility as they have shown cell viability with mature cell morphology against preosteoblast and HEK-293 cell lines under standard in vitro conditions. The enhanced biological activities of the scaffolds were found by increasing the Zn amount. Thus, newly designed polymeric composite scaffolds would be promising materials to repair and regenerate fractured bone tissue.