Reverse Technique Research Articles

Validation of RP-HPLC-PDA method for determination of five Antidiabetic drugs in Pharmaceutical Formulations

A gradient reverse phase technique can be considered as a good method for separation and quantification of drugs. High-performance liquid chromatography was developed and verified for the determination of five antidiabetic drugs “Metformin, Glipizide, Repaglinide, Acarbose and Glimepiride” in pure form and in their pharmaceutical formulations within 21.8 minutes. Separation was carried out using the C18 column (150 mm×4.6 mm, 5 μm) with a mobile phase consisting of two solutions (A and B). PDA detection was set at 240 nm and temperature 30C. The retention time of metformin, glipizide, repaglinide, acarbose and glimepiride was detected at 2.12, 10.37, 12.49, 19.8, 21.8 min. respectively. Also, limits of detection were reported to be 0.0025, 0.0016, 0.005, 0.003, 0.002 mg/ml and limits of quantification as 0.0078,0.005, 0.017, 0.0091, 0.006 mg/ml. This analytical method, according to ICH standards, can also be relevant and beneficial for pharmaceutical and quality control studies.

Collapse behavior of corrugated stiffened pressure shells under external hydrostatic pressure considering actual fabrication imperfections: A reverse modeling technique

The pressure shell is the most critical load-bearing component in submersible vehicles. It is mainly used to withstand the enormous seawater pressure. In this study, a corrugated stiffened pressure shell was proposed to address the problem of low compression performance of the traditional cylindrical pressure shell. Nine corrugated shells made of aluminum alloy with varying corrugation parameters were created using CNC machining. After welding and sealing treatment, hydrostatic pressure tests were conducted on the shells to investigate the impact of parameters such as wall thickness, number of corrugations, and corrugation height on their compression performance. The shells were measured using a 3D scanner, and the resulting data was used for reverse modeling. The analysis focused on the failure behavior of corrugated shells with geometric imperfections under uniform external pressure using nonlinear finite element analysis. The results indicate that increasing the wall thickness or corrugation height can significantly improve the compression performance of the shells. The position of collapse remains consistent with the location of the maximum Mises stress. Furthermore, it was discovered that the corrugated structure also has an additional advantage in retarding the generation and expansion of diamond-shaped defects on the shell surface. The equilibrium paths of all corrugated shells maintained a smooth and continuous state, demonstrating stable buckling behavior. The numerical calculations were in excellent agreement with the experimental results, highlighting the advantages of the reverse modeling technique. This study provides new insights for the structural design of submarine pressure shells and explores more reasonable and feasible stiffening methods.

Transient square pulse-electric field induction of monosex-male reversal of the eggs of Nile tilapia (Oreochromis niloticus L., Chitralada)

We present an alternative technique of monosex-male reversal for Nile tilapia using transient square pulse-electric field inductions to enhance sex reversal rate of tilapia eggs by methyltestosterone (Oreochromis niloticus L., Chitralada). Male tilapia is preferred for aquaculture because of better size and growth rate. The egg membrane was permeabilised by an electric field pulse allowing a minimalized androgen hormone dose of 17alpha-methyltestosterone (MT) (μg l−1 concentration) to achieve monosex sex-male reversal. The technique achieved large-scale inductions of 2000 eggs rather than for individual eggs and was aimed at commercialization (Thailand petty patent no. 13516). The eggs of O. niloticus obtained from our parent breeding stocks were carefully selected to be in the segmentation-pharyngula stage (2–3 dpf - day post fertilization) for electrical inductions in a pulsed-electric field generated between narrow parallel-plate electrodes. The electrodes were powered with an adjustable signal pulse-generator (SPG) developed for on-site operations. The induction medium was prepared using HEPES buffer mixed with a minimized concentration of MT. We experimentally optimized inductions by adjusting the number of square wave pulses, pulse amplitude, pulse durations (period) and a mark-space ratio (pulse width: negative half of period) for the optimum results. A dose of 350 V (electric field intensities of 87.50 kV m−1) of 3 square pulses with 100 μs pulse-period (50:50 mark space ratio) gave the maximum rate of male-sex reversal rate (MSR) of 89.42 ± 2.28 (SD)%, hatching rate (HR) of 93.33 ± 0.58% and survival rate (SR) of 87.49 ± 1.71%, respectively. The off-spring rate (OSR) or sex ratio of the controls were 59.71 ± 3.00% male and 46.33 ± 1.53% female from a hatching rate (HR) of 91.33 ± 1.53% and a survival rate (SR) of 85.08 ± 4.16%, respectively.

A learnable full-frequency transformer dual generative adversarial network for underwater image enhancement

Underwater applications present unique challenges such as color deviation, noise, and low contrast, which can degrade image quality. Addressing these issues, we propose a novel approach called the learnable full-frequency transformer dual generative adversarial network (LFT-DGAN). Our method comprises several key innovations. Firstly, we introduce a reversible convolution-based image decomposition technique. This method effectively separates underwater image information into low-, medium-, and high-frequency domains, enabling more thorough feature extraction. Secondly, we employ image channels and spatial similarity to construct a learnable full-frequency domain transformer. This transformer facilitates interaction between different branches of information, enhancing the overall image processing capabilities. Finally, we develop a robust dual-domain discriminator capable of learning spatial and frequency domain characteristics of underwater images. Extensive experimentation demonstrates the superiority of the LFT-DGAN method over state-of-the-art techniques across multiple underwater datasets. Our approach achieves significantly improved quality and evaluation metrics, showcasing its effectiveness in addressing the challenges posed by underwater imaging. The code can be found at https://github.com/zhengshijian1993/LFT-DGAN.

C. Halicacabum derived “turn-on-off” non-invasive molecularly imprinted polymer for selective profiling of 2-(3,4-dihydroxy phenyl) ethylamine in human fluid samples

A rationally designed “Turn on-off” molecularly imprinted fluorescent probe SCDs-MPs serves as a robust platform for the specific identification of aberrant dopamine (DA) levels. In this study, carbon dots (SCDs) were synthesized usingCardiospermum Halicacabum leaf extract as a carbon source via a step hydrothermal process. The synergistic integration of the synthesized fluorophore SCDs (QY–27.6 %) with molecularly imprinted elements via reverse micro-emulsion technique forms novel C. Halicacabum derived SCDs-MPs nanocomposite. The synthesized SCDs-MPs possess various inimitable properties such as hydrophilicity (WCA of 12.9°) suitability for detection in aqueous media, the narrow bandgap of 3.45 eV attributed to the electron-donating nature, and photostability. Fluorescence lifetime, from 6.38 ns to 6.17 ns after adding dopamine to SCDs-MPs, and zeta potential studies (–32.9 mV to –23.9 mV) validate the static fluorescence quenching mechanism in SCDs-MPs. Under various modifications and experimental conditions, SCDs-MPs consistently achieved a low dopamine detection limit of 6.4 pM within the range of 0–50 µM. Excellent recovery experiments in human fluid samples (98–102 %) confirm the fluorescent probe’s empirical reliability. The MTT assay confirms the superior biocompatibility of SCDs-MPs, with cell viability remaining at ± 24.03 % at a concentration of 200 µg/ml suggesting the safe usage for invitro administration. This opens new possibilities for utilizing C. Halicacabum derived SCDs-MPs material in biomedical contexts.

Three-dimensional super-resolution crack imaging in industrial manufactured components: A truncated correlation photothermal coherence tomography approach

The challenge of detecting cracks in powder metallurgy (PM) components has been a topic of interest for many years, with no practical commercial solution currently in place. This study employs enhanced truncation-correlation photothermal coherence tomography (eTC-PCT) to visualize 3D cracks within PM automotive parts. Through the application of effective diffusion-wave reversal techniques, blurred infrared thermophotonic images of subsurface defects (cracks) in (“green”) compressed metal PM components were restored to their original geometric resolution over the entire depth range. This approach enabled the creation of 3-dimensional depth-resolved photothermal tomographic images and cross-sectional mappings of cracks. The developed technique reveals the precise spatial dimensions of surface and subsurface cracks, reaching depths of down to 3 mm (not an upper limit) that conventional thermal imaging cannot access due to limitations imposed by the depth-integrated nature of conventional thermal-wave imaging, the properties of PM materials, and the physics of spreading diffusion. The super-resolution method was further applied to a sintered automotive part, specifically validating the efficacy of eTC-PCT for non-destructive imaging (NDI) in manufactured automotive components. Diffusion reversal imaging shows promise as a non-destructive testing (NDT) tool, with potential applications in a wide range of manufactured products, including both the green and sintered stages of automotive component production.

Virtual parameter calibration of pod pepper seeds based on discrete element simulation

In order to achieve numerical optimization of the pod pepper seed sowing device, the contact parameters of pod pepper seeds were calibrated, with the angle of repose used as the response value. A set of discrete element method (DEM) models of pod pepper seeds was developed to simulate the formation of seed repose angles using reverse engineering reconstruction techniques. An eight-factor, three-level response surface experiment based on the Box-Behnken central combination test method was performed to study the effects of various factors on the angle of repose of seeds. The angle of repose obtained from physical experiments with a value of 27.56° was taken as the target value. The optimal combination of parameters is obtained as follows: seed Poisson's ratio of 0.22, seed shear modulus of 15.47 MPa, seed-to-seed static friction coefficient of 0.25, seed-to-seed rolling friction coefficient of 0.67, seed-to-seed collision recovery coefficient of 0.64, seed-to-steel-plate static friction coefficient of 0.55, seed-to-steel-plate rolling friction coefficient of 0.45, and seed-to-steel plate collision recovery coefficient of 0.34. A two-sample t-test of the angle of repose obtained by the cylinder lifting method and the pumping plate method against the target value yielded P > 0.05, indicating the reliability of the simulation experiments.

Developing Next-Generation Live Attenuated Vaccines for Porcine Epidemic Diarrhea Using Reverse Genetic Techniques.

Porcine epidemic diarrhea virus (PEDV) is the etiology of porcine epidemic diarrhea (PED), a highly contagious digestive disease in pigs and especially in neonatal piglets, in which a mortality rate of up to 100% will be induced. Immunizing pregnant sows remains the most promising and effective strategy for protecting their neonatal offspring from PEDV. Although half a century has passed since its first report in Europe and several prophylactic vaccines (inactivated or live attenuated) have been developed, PED still poses a significant economic concern to the swine industry worldwide. Hence, there is an urgent need for novel vaccines in clinical practice, especially live attenuated vaccines (LAVs) that can induce a strong protective lactogenic immune response in pregnant sows. Reverse genetic techniques provide a robust tool for virological research from the function of viral proteins to the generation of rationally designed vaccines. In this review, after systematically summarizing the research progress on virulence-related viral proteins, we reviewed reverse genetics techniques for PEDV and their application in the development of PED LAVs. Then, we probed into the potential methods for generating safe, effective, and genetically stable PED LAV candidates, aiming to provide new ideas for the rational design of PED LAVs.

Influenza A virus NS1 effector domain is required for PA-X-mediated host shutoff in infected cells.

Many viruses inhibit general host gene expression to limit innate immune responses and gain preferential access to the cellular translational apparatus for their protein synthesis. This process is known as host shutoff. Influenza A viruses (IAVs) encode two host shutoff proteins: nonstructural protein 1 (NS1) and polymerase acidic X (PA-X). NS1 inhibits host nuclear pre-messenger RNA maturation and export, and PA-X is an endoribonuclease that preferentially cleaves host spliced nuclear and cytoplasmic messenger RNAs. Emerging evidence suggests that in circulating human IAVs NS1 and PA-X co-evolve to ensure optimal magnitude of general host shutoff without compromising viral replication that relies on host cell metabolism. However, the functional interplay between PA-X and NS1 remains unexplored. In this study, we sought to determine whether NS1 function has a direct effect on PA-X activity by analyzing host shutoff in A549 cells infected with wild-type or mutant IAVs with NS1 effector domain deletion. This was done using conventional quantitative reverse transcription polymerase chain reaction techniques and direct RNA sequencing using nanopore technology. Our previous research on the molecular mechanisms of PA-X function identified two prominent features of IAV-infected cells: nuclear accumulation of cytoplasmic poly(A) binding protein (PABPC1) and increase in nuclear poly(A) RNA abundance relative to the cytoplasm. Here we demonstrate that NS1 effector domain function augments PA-X host shutoff and is necessary for nuclear PABPC1 accumulation. By contrast, nuclear poly(A) RNA accumulation is not dependent on either NS1 or PA-X-mediated host shutoff and is accompanied by nuclear retention of viral transcripts. Our study demonstrates for the first time that NS1 and PA-X may functionally interact in mediating host shutoff.IMPORTANCERespiratory viruses including the influenza A virus continue to cause annual epidemics with high morbidity and mortality due to the limited effectiveness of vaccines and antiviral drugs. Among the strategies evolved by viruses to evade immune responses is host shutoff-a general blockade of host messenger RNA and protein synthesis. Disabling influenza A virus host shutoff is being explored in live attenuated vaccine development as an attractive strategy for increasing their effectiveness by boosting antiviral responses. Influenza A virus encodes two proteins that function in host shutoff: the nonstructural protein 1 (NS1) and the polymerase acidic X (PA-X). We and others have characterized some of the NS1 and PA-X mechanisms of action and the additive effects that these viral proteins may have in ensuring the blockade of host gene expression. In this work, we examined whether NS1 and PA-X functionally interact and discovered that NS1 is required for PA-X to function effectively. This work significantly advances our understanding of influenza A virus host shutoff and identifies new potential targets for therapeutic interventions against influenza and further informs the development of improved live attenuated vaccines.

Investigation of dextran-coated magnetic nanoparticles encapsulated by medication and modified with folate for targeted drug delivery: Invitro and docking studies

In this study, we synthesized dextran (DEX)-coated iron oxide (Fe3O4) and encapsulated it by the anticancer drug cisplatin (CP). This nano-composite functionalized with folic acid (FA) molecules for targeted delivery. These nanoparticles (NPs) were then used as nanocarriers for the targeted administration of CP for treating thyroid tumor cancer. The Fe3O4 NPs were synthesized using a chemical technique. The development of the Fe3O4@DEX-CP-FA nanosystem was achieved using a reverse microemulsion technique. The morphological features of the NPs were characterized using several methods, including dynamic light scattering, atomic force microscopy, vibrating sample magnetometry, high-resolution transmission electron microscopy, and field emission scanning electron microscopy. The docking study has verified that nanoparticles have anti-proliferative effects in thyroid cancer by attaching strongly to molecular targets. The MTT test evaluated the effects of a curative Fe3O4@DEX-CP-FA effect on cancerous and non-cancerous cell lines. The results obtained from the formulation of Fe3O4@DEX-CP-FA revealed the presence of spherical particles with an average size of 107.3 nm, a zeta potential of −28.7 mV, and a polydispersity value of 0.055 mV. Depending on the dose, the nanosystem exhibited cytotoxic effects on thyroid tumor (TT) and normal human thyroid (NHT) cell lines. The study findings indicate that Fe3O4@DEX-CP-FA demonstrated sustained antitumor efficacy while not revealing a harmful impact on normal cells.

Optimized Management of Patulous Eustachian Tube: Shim Size Modifications to Minimize Middle Ear Effusion and Enhancing Treatment Outcomes.

Objective: In this retrospective case series, we reported 4 patients presenting with a patulous Eustachian tube (PET) to highlight our institutional management approach to PET with shim insertion and a modified shim with hydroxyapatite injection. Methods: A single institution retrospective review. Results: One case was complicated by otitis media effusion; thus, the shim was downsized under local anesthesia with an immediately improved effusion. Another patient managed with a bilateral shim of the same size but is still symptomatic on one side; therefore, we upsized it, and the symptoms disappeared. The last one developed biofilm formation and thick secretion even after downsizing. Hydroxyapatite injection was performed under local anesthesia using the same shim insertion protocol. Conclusion: Shim insertion for the treatment of PET is considered a safe, reversible, and adjustable technique, giving satisfactory results while avoiding middle ear effusion. It can be performed under local or topical anesthesia in the clinic, and size adjustment can be considered to get maximum relief without middle ear effusion. This case series highlights that adjusting the size of the shim is a suggested method to eliminate symptoms and avoid complications of shim without the need for myringotomy and ventilation tube.

Development and biological characterization of an infectious cDNA clone of NADC34-like PRRSV.

Porcine Reproductive and Respiratory Syndrome virus (PRRSV) causes high abortion rates in gestating sows and stillbirths, as well as high piglet mortality, seriously jeopardizing the pig industry in China and worldwide. In this study, an infectious clone containing the full-length genome of NADC34-like PRRSV was constructed for the first time using reverse genetic techniques. The gene was amplified segmentally onto a plasmid, transfected into BHK-21 cells, and the transfected supernatant was harvested and transfected into PAM cells, which showed classical cytopathic effects (CPE). The virus rJS-KS/2021 was successfully rescued which could be demonstrated by Western Blot and indirect immunofluorescence assays. Its growth curve was similar to the original strain. Replace the 5'UTR and 3'UTR of rJS-KS/2021 with 5'UTR and 3'UTR of HP-PRRSV (strain SH1) also failed to propagate on MARC-145. In this study, an infectious clone of NADC34-like was constructed by reverse genetics, replacing the UTR and changing the cellular tropism of the virus. These findings provide a solid foundation for studying the recombination of different PRRSVs and the adaption of PRRSVs on MARC-145 in the future.

A vehicle firmware security vulnerability: an IVI exploitation

In the last years, the increasing vehicular technology has led to a surge in cybersecurity attacks, particularly regarding connected vehicles and their vulnerable infotainment systems. This paper explores the vulnerabilities within an In-Vehicle Infotainment (IVI) system firmware, focusing on the Gen5W_L multimedia device utilized in Hyundai, Kia, and Genesis vehicles. Leveraging reverse engineering techniques, the study uncovers several security issues within the firmware, allowing for the creation and installation of custom firmware. The paper introduces Chimaera, a reverse engineering attack targeting the IVI system firmware, which exploits a printf vulnerability introduced by statically compiling the mbedtls library. After a reverse engineering analysis and injecting malicious assembly code directly in the IVI firmware, the attack enables the extraction of sensitive information from the firmware files like the cryptographic keys to install a customized firmware. The research shows that exploiting these vulnerabilities facilitates the installation of insecure firmware, granting attackers unauthorized access to vehicle functionalities. This includes the possibility to inject CAN bus messages, potentially compromising critical vehicle systems such as radio controls and safety features. The findings underscore the need for robust cybersecurity measures within automotive systems and highlight the significance of vulnerability assessment to mitigate security risks in connected vehicles.

Block and Statistical Copolymers of Methacrylate Monomers with Dimethylamino and Diisopropylamino Groups on the Side Chains: Synthesis, Chemical Modification and Self-Assembly in Aqueous Media.

The synthesis of amphiphilic diblock and statistical (random) copolymers of poly(dimethylamino ethyl methacrylate) and poly((2-(diisopropylamino) ethyl methacrylate) using the reversible addition-fragmentation chain transfer polymerization technique (RAFT polymerization) is reported. The precursor copolymers were chemically modified to create derivative copolymers of polyelectrolyte and polyampholyte nature with novel solution properties. Moreover, their molecular and physicochemical characteristics, as well as their self-assembly in aqueous media as a function of molecular architecture and composition, are investigated by using size exclusion chromatography, spectroscopic characterization techniques and light scattering techniques. Furthermore, the behavior and properties of the obtained micelles and aggregates were studied, depending on the pH, temperature and ionic strength of the aqueous solutions. The response of the systems to changes in these parameters shows interesting behavior and new properties that are useful for their utilization as nanocarriers of pharmaceutical compounds.

A Pilot Study of Observation Poisoning on Selective Reincarnation in Multi-Agent Reinforcement Learning

This research explores the vulnerability of selective reincarnation, a concept in Multi-Agent Reinforcement Learning (MARL), in response to observation poisoning attacks. Observation poisoning is an adversarial strategy that subtly manipulates an agent’s observation space, potentially leading to a misdirection in its learning process. The primary aim of this paper is to systematically evaluate the robustness of selective reincarnation in MARL systems against the subtle yet potentially debilitating effects of observation poisoning attacks. Through assessing how manipulated observation data influences MARL agents, we seek to highlight potential vulnerabilities and inform the development of more resilient MARL systems. Our experimental testbed was the widely used HalfCheetah environment, utilizing the Independent Deep Deterministic Policy Gradient algorithm within a cooperative MARL setting. We introduced a series of triggers, namely Gaussian noise addition, observation reversal, random shuffling, and scaling, into the teacher dataset of the MARL system provided to the reincarnating agents of HalfCheetah. Here, the “teacher dataset” refers to the stored experiences from previous training sessions used to accelerate the learning of reincarnating agents in MARL. This approach enabled the observation of these triggers’ significant impact on reincarnation decisions. Specifically, the reversal technique showed the most pronounced negative effect for maximum returns, with an average decrease of 38.08% in Kendall’s tau values across all the agent combinations. With random shuffling, Kendall’s tau values decreased by 17.66%. On the other hand, noise addition and scaling aligned with the original ranking by only 21.42% and 32.66%, respectively. The results, quantified by Kendall’s tau metric, indicate the fragility of the selective reincarnation process under adversarial observation poisoning. Our findings also reveal that vulnerability to observation poisoning varies significantly among different agent combinations, with some exhibiting markedly higher susceptibility than others. This investigation elucidates our understanding of selective reincarnation’s robustness against observation poisoning attacks, which is crucial for developing more secure MARL systems and also for making informed decisions about agent reincarnation.

Reverse Atom Capture on Perovskite Surface Enabling Robust and Efficient Cathode for Protonic Ceramic Fuel Cells.

Protonic ceramic fuel cells (PCFCs) hold potential for sustainable energy conversion, yet their widespread application is hindered by the sluggish kinetics and inferior stability of cathode materials. Here, a facile and efficient reverse atom capture technique is developed to manipulate the surface chemistry of PrBa0.5Sr0.5Co1.5Fe0.5O5+ δ (PBSCF) cathode for PCFCs. This method successfully captures segregated Ba and Sr cations on the PBSCF surface using W species, creating a (Ba/Sr)(Co/Fe/W)O3- δ (BSCFW)@PBSCF heterostructure. Benefiting from enhanced kinetics of proton-involved oxygen reduction reaction and strengthened chemical stability, the single cell using the optimized 2W-PBSCF cathode demonstrates an exceptional peak power density of 1.32W cm-2 at 650°C and maintains durable performance for 240h. Theoretical calculations unveil that the BSCFW perovskite delivers lower oxygen vacancy formation energy, hydration energy, and proton transfer energy compared to the PBSCF perovskite. This protocol offers new insights into advanced atom capture techniques for sustainable energy infrastructures.

The Application of Reverse Z-Plasty Design in Medial Canthal Skin Redundancy Reconstruction Surgery.

To investigate the clinical outcomes of reverse Z-plasty in the reconstruction of epicanthal fold. We conducted a retrospective analysis on clinical data from patients who underwent medial canthal skin redundancy reconstruction surgery from September 2019 to January 2023. The surgical procedure involved a preoperative design for the incision line, suborbicularis oculi dissection to create a muscle flap, and the use of a reverse Z-flap for the reconstruction of the lateral canthal fold. Postoperative follow-up assessments focused on the intercanthal distance, positional changes of the medial canthus point, alterations in the medial canthus angle, and patient satisfaction levels. The statistical evaluation was carried out utilizing paired t -tests, with a P -value of less than 0.05 denoting statistical significance. Postsurgery, the lacrimal prominences were less exposed, and inner canthal angles naturally reshaped. Inconspicuous scarring with diminished reverse Z-plasty marks was noted within 3 months. The average ICD has increased by 3 to 6mm, corresponding to elongation ratios of 9.09% to 28.30%. Preoperatively, the ICD averaged 31.25±2.32mm, expanding postoperatively to 35.19±2.26mm. The canthal angle enlarged significantly from 49.031±6.627 to 62.188±6.662. Inner canthal points shifted notably postsurgery, with a decrease in x-value and an increase in y-value, signalling a movement upwards and away from the nose. Patient satisfaction is high. The reverse Z-plasty technique has proven to be an effective approach for reconstructing the epicanthal fold. The clarity and precision of the incision design, coupled with the stability of postoperative results, demonstrate that this method can reliably achieve successful epicanthal fold reconstruction.

PROTOTYPING OF A TWO WHEELER CLUTCH HUB USING REVERSE ENGINEERING TECHNOLOGY

A clutch hub is a critical component in a two wheeler manual transmission system, responsible for transferring rotational power from the engine to the transmission gears and providing a mechanism for disengaging the gears to allow for smooth gear changes. The clutch hub is placed between clutch basket and pressure plate. The clutch plates are mounted on it. It has teeth at center hole which rotate with main shaft. The prototyping of clutch hub using reverse engineering technique, making it essential to understand its design and functionality reverse engineering is employed to deconstruct an existing clutch hub, analyze its dimensions and materials, and create an accurate digital 3D model is created using computer aided design software, by scanning the part and prototyping of clutch hub is made by using 3D printing technology. Key Words: Clutch hub, Reverse engineering, 3D Model, Prototyping, 3D printing.

Uniform and local degradation of epoxy-based powder coatings: Salt transport and accelerated exposure analysis

The barrier performance of epoxy-based powder coatings for pipelines was evaluated through salt transport measurements through free-standing coating films and via cyclic testing of coated steel panels. The permeability of salt through the free-standing coating films was measured using reverse osmosis techniques under hydraulic pressures relevant to industrial use. These tests showed that fusion bonded epoxy (FBE) and high-performance powder coating (HPPC) have low salt permeability. Accelerated exposure tests were then conducted on the coated steel panels, subjecting them to humidified environments, ultraviolet (UV) light, and salt/fog conditions, all in accordance with ASTM D5894. Some of the exposure conditions (e.g., intensity of UV light and humidity) were modified to examine the impact of each parameter on the relative performance of these coating systems. The reversibility of the coating properties was characterized by a thermal cycling protocol and adhesion performance analysis. Alternative exposure to dry- and wet-cycles (at 60 °C and 50 °C, respectively), salt/fog conditions and UV light results in irreversible damage to the coatings as early as two weeks. However, coated panels exposed to a lower UV intensity (one tenth of the value defined by the standard) showed minimal degradation of FBE, meaning that the most critical parameter was the UV radiation exposure. For one 336-h ageing sequence under UV exposure, the HPPC exhibited superior performance compared to FBE. More importantly, our extended exposure sequences showed that while the FBE coating structure undergoes a slow ablation process, indicating significant surface damage, it still retains its effectiveness as a barrier. However, the osmotic pressures around coated pipes and the pre-existing, unavoidable porosity throughout the coating thickness can facilitate local through-thickness pinholes, which could potentially serve as areas susceptible to cathodic disbondment.

Electrochemical potential of chitosan nanoparticles obtained by the reverse micellar process

Chitosan nanoparticles are synthesized by the reverse micellar technique using heptane as solvent and hexamine as surfactant. XRD, FTIR, and SEM/EDAX analyses are performed to investigate the structural and morphological behavior of chitosan nanoparticles. XRD shows the crystalline nature of the materials with peaks appeared at 2θ =17.8 °, 25.5 °, 31.2 °, 36.4 °, 44.7 °, and 48.5 °. The average crystallite size of obtained chitosan nanoparticles is 25 nm. The identification of functional groups in both pure chitosan and chitosan nanoparticles are compared using FTIR analysis. Noticed at wavenumbers 3435 cm−1 and 3460 cm−1 corresponds to the stretching vibration of the –NH2 and –OH functional groups. SEM shows the uniform morphology of the materials and EDAX shows the presence of various elements (carbon, nitrogen, oxygen, aluminum and chlorine) in both the materials. The electrochemical behavior of the nanoparticles was analyzed by cyclic voltammetry analysis and galvanostatic charging/discharging. Electrochemical faradaic performance identifies chitosan nanoparticles as effective electrode materials in pseudo capacitors.