Limit Load Research Articles

Transverse compressive behavior of plain and polypropylene fiber-reinforced concrete infilled steel tubes as hybrid steel-concrete nodes for discrete reticulated shell structures

This study investigates using concrete infilled steel tubes as hybrid nodes for discrete reticulated shell structures under compressive loading transverse to the tube axis. Three configurations were tested: empty, plain concrete infilled and polypropylene fiber-reinforced concrete infilled steel tubes. Displacement-controlled loading was applied through welded steel plates. Simplified beam theory models and nonlinear finite element analysis were used to evaluate the structural behavior. The concrete infilled steel tube specimens had higher stiffness and load-bearing capacity than the empty ones. The structural behavior of the concrete infilled specimens could be split into pre- and post-split-tensile cracking phases. No significant difference was found between the plain and fiber-reinforced concrete specimens under loads up to 1500 kN, which was the load limit of the testing machine. An additional fiber-reinforced concrete specimen, tested on a higher capacity machine, had a load-bearing capacity of 2400 kN and exhibited ductile failure.

Tackle power outage effects for Egypt's energy crisis via localized optimum load shedding

This paper presents an approach for selecting optimal load-shedding values for individual subscribers or consumers. Implementing this method can bring positive outcomes for consumers by minimizing risks and economic losses caused by power outages. It enables network operators to address power supply deficits and overcome network issues, especially those affecting weaker areas. The optimal load-shedding values are determined by employing IGWA (Improved grey wolf algorithm) through a Graded Objective Function Strategy. The proposed method essentially centered on categorizing loads into two levels based on their importance. The first level includes essential loads, the disruption of which results in risks or significant economic losses. The second level comprises less critical loads, and they do not have more risks or economic losses when power outages. This approach applies specifically to residential loads. The control scheme diagram of disconnecting and reconnecting the current is established by estimating the critical load limit during power outage periods. The necessary arrangements can be made, leading to a proactive measure against risks and losses. The proposal has been implemented in Egypt's electricity network. this proposed method provides a simple and effective solution to the ongoing crisis and provides permanent resolution of problems arising from power outages.

Analysis and experimental evaluation framework for buckling and post-buckling of composite stiffened panels

The composite thin-walled stiffened panel exhibits considerable potential for post-buckling bearing capacity. However, due to the limitations in post-buckling analysis and experimental evaluation capabilities, local buckling under limited loads is not permissible for current aircraft composite panels, significantly diminishing the weight reduction effect of composite panels. In this paper, experimental research on composite fuselage curved panels under combined compression and shear loads was conducted with an experimental system. The buckling analysis and failure prediction of composite fuselage curved panels were performed by the finite element method, using the interlaminar failure criterion and an improved Tsai-Wu failure criterion. Meanwhile, interaction formulaes were utilized to predict buckling correlation curves and failure envelopes. The results show that the finite element model with improved criteria and the rapid analysis method based on interaction formulaes exhibit high accuracy, which are available for properties analysis of composite panels. The experimental techniques and analytical methods proposed in this paper can provide a way to evaluate the buckling and post-buckling performance of composite stiffened panels.

3D limit analysis of reinforced concrete with sliding along smeared cracks

Limit analysis (LA) is successfully used for investigating the bearing capacity of reinforced concrete (RC) structures. Some cautions must be taken when using this method for RC since the concrete component exhibits a softening behavior with decreasing strength and limited ductility. A commonly adopted provision consists of considering isotropic reduced values of concrete strength to be input in the analysis (empirical effectiveness factors). In this paper, an alternative and completely new approach is proposed and investigated in which concrete strength is weakened in a more targeted manner. To that purpose, the commonly used 3D truncated Mohr-Coulomb (TMC) criterion is adopted to classically describe the compressive, tensile, and shear failure of concrete. However, TMC is here in an original way enriched by additional constraints that allow to account for weakness and anisotropy induced by preferential failure patterns, assumed a priori. The limit analysis approach is then formulated for two dual analyses in the convex optimization framework, making it possible to quantify the numerical error and obtain a lower and an upper bound of the limit load. Numerical examples illustrate the agreement of the formulation with academic results and laboratory tests.

Preparation and Characterization of Universal Liquid Proliposomes Encapsulating Water-soluble Efficacious Substances.

Liposomes were extensively used for cosmetics and pharmaceuticals due to their versatility, biocompatibility, and biodegradability, as well as the ability to encapsulate water-soluble and fat-soluble substances. However, some challenges remain unsolved, including poor stability, complex preparation process, limited encapsulation efficiencies (EE%) and drug loading capacity (DLC%). We herein prepared universal liquid proliposomes by rotary evaporation method and optimized formulations with different pH, glycerol content, ethanol content and preparation process. The EE% of water-soluble substances was above 85%, and the maximum DLC% was 37.5%. In 7 different conditions, the optimal formulation of the proliposomes remained stable over 60 days. The excellent stability of proliposomes and nicotinamide liposomes and their essence, when applied to cosmetic formulations, was confirmed by the Turbiscan stability analyzer. The proposed universal liquid proliposomes can form liposomes encapsulating a variety of water-soluble substances rapidly, making them an accessible and versatile tool for improving the stability and applicability of water-soluble raw materials.

A Comprehensive Review of Challenges in Oral Drug Delivery Systems and Recent Advancements in Innovative Design Strategies.

The oral route of drug administration is often preferred by patients and healthcare providers due to its convenience, ease of use, non-invasiveness, and patient acceptance. However, traditional oral dosage forms have several limitations, including low bioavailability, limited drug loading capacity, and stability and storage issues, particularly with solutions and suspensions. Over the years, researchers have dedicated considerable effort to developing novel oral drug delivery systems to overcome these limitations. This review discusses various challenges associated with oral drug delivery systems, including biological, pharmaceutical, and physicochemical barriers. It also explores common delivery approaches, such as gastroretentive drug delivery, small intestine drug delivery, and colon-targeting drug delivery systems. Additionally, numerous strategies aimed at improving oral drug delivery efficiency are reviewed, including solid dispersion, absorption enhancers, lipidbased formulations, nanoparticles, polymer-based nanocarriers, liposomal formulations, microencapsulation, and micellar formulations. Furthermore, innovative approaches like orally disintegrating tablets (ODT), orally disintegrating films (ODF), layered tablets, micro particulates, self-nano emulsifying formulations (SNEF), and controlled release dosage forms are explored for their potential in enhancing oral drug delivery efficiency and promoting patients' compliance. Overall, this review highlights significant progress in addressing challenges in the pharmaceutical industry and clinical settings, offering novel approaches for the development of effective oral drug delivery systems.

Mechanical Robustness Analysis of Semiconductors with a Single Needle Probe Card Using Acoustic Emissions

The combination of indentation testing and acoustic emission (AE) is widely used to analyze the fracture toughness of test substrates. In the manufacturing of semiconductor devices this material parameter also plays an important role. During the so-called wafer testing inside a wafer prober small probe tips are pressed onto the chip surface to check its performance. To prevent damaging the chip by that, the fracture toughness and load limit of it has to be defined in a prequalification step. This paper presents a test system that imitates the wafer testing process as close as possible and uses acoustic emission to detect appearing cracks and thereby also the load limit. The frontend of the test setup consists of a modular single needle probe card which can be placed in a wafer prober. Also, the indenter properties (tip diameter, stiffness, etc.) can be adjusted to the probe used later on during productive wafer testing to ensure realistic probing conditions. A piezoelectric sensor and a full strain gauge Wheatstone bridge are implemented close to the single indenter to measure the AEs and the applied contact force respectively. The signal-to-noise-ratios (SNRs) of both sensors are improved with an own analog amplifier module before recording them with an USB oscilloscope. A developed measurement software (LabVIEW) is used to adjust measurement parameters (trigger limit, record length, conversion factors, etc.) and automatically store and separate measurement data from different acoustic events and imprints. To evaluate the result files a second software tool (MATLAB) reads the files out and clusters the recorded events to separate crack signals from electrical and mechanical disturbances. With a prototype first test results are generated and the functionality and accuracy of the measurement concept is proven.

Damage mechanism identification and failure behavior of 2D needle-punched SiCf/SiC composites based on acoustic emission and digital image correlation

In order to improve the reliability of damage analysis for SiCf/SiC composites, an identification method of damage mechanism was established by combining in-situ acoustic emission (AE) and digital image correlation (DIC). The corresponding failure behavior of 2D needle-punched SiCf/SiC composites during ambient-temperature tensile test was investigated in detail. Through a machine learning k-means algorithm, AE signals could be effectively divided into five clusters: friction and sliding, interface damage, matrix cracking, individual fiber breaks and collective fiber breaks. DIC results show that the surface strain of composites increased non-uniformly during the tensile process, and the architecture of the composites had a significant influence on the initiation and propagation of cracks. To summarize, the tensile process consisted of three stages: the elastic stage, the rapid propagation of matrix cracks, the coordinated fiber fracture within the large strain bands. The failure of composites was dominated by the limited load transferring ability of the interface.

Impact of dissolution medium pH and ionization state of the drug on the release performance of amorphous solid dispersions

Amorphous solid dispersions (ASDs) are widely employed as a strategy to improve oral bioavailability of poorly water soluble compounds. Typically, optimal dissolution performance from a polyvinylpyrrolidone vinyl acetate (PVPVA) based ASD is observed at relatively low drug loading limit. Above a certain drug load, termed limit of congruency (LoC), the release from ASDs significantly decreases. So far, the majority of the dissolution behavior has been tested in conditions where the drug primarily exists in unionized form. In this work, the impact of pH of the dissolution environment on the release performance of ASDs of an ionizable drug was studied. Atazanavir (ATZ), a weakly basic drug with a pKa of 4.5 was used as a model compound and PVPVA was used as a non-ionizable matrix polymer. Dissolution rate was measured using Wood's apparatus which normalizes the surface area of the dissolving tablet. The pH of the dissolution media was varied between 1 and 6.8, cover a range where ATZ exists as >99% ionized or unionized species. At pH 6.8, near complete release was observed only when the drug load was ≤ 6%. Unlike typically observed drastic decline in release behavior for PVPVA based ASDs above LoC, ATZ ASDs underwent gradual decline in dissolution behavior when the DL was increased to 8%. This was attributed to potential formation of an ATZ-PVPVA associated phase with dissolution rate slower than neat PVPVA. However, the 10% DL ASD showed negligible ATZ release. On another extreme (pH 1) where ATZ is ∼100% ionized, the dissolution rate of ATZ was faster than that of PVPVA. ASD dissolution rate was found to be slower than that of the neat drug but faster than PVPVA and interestingly, did not change with DL. This can be attributed to formation of an ionized ATZ-PVPVA phase which controls the dissolution rate of the ASD. At pH 3, where the drug is ∼97% ionized, near complete release was observed for drug loads ≤ 8%. To observe significant increase in drug loading with near complete release, >98% ionization of ATZ was required. At pH 2 where ATZ is ∼99.7% ionized, near complete release was observed for drug loads up to 30%. Furthermore, the deterioration in dissolution performance with an increase in drug load continued to be gradual at pH 2. The enhancement in dissolution performance did not correlate with solubility enhancement of ATZ due to ionization. We theorize that the enhancement in the dissolution performance due to ionization is the result of formation of an ionized ATZ-PVPVA phase which increases the hydrophilicity and the miscibility of the ASD. This can help resist water induced phase separation during ASD dissolution and therefore, result in continuous, and congruent dissolution of the drug and polymer.

Effect of Quadriceps Tendon Autograft Preparation and Fixation on Graft Laxity During Suspensory Anterior Cruciate Ligament Reconstruction: A Biomechanical Analysis.

Favorable collagen fibril density and thickness combined with advances in graft preparation and fixation have significantly increased interest in the quadriceps tendon (QT) autograft for anterior cruciate ligament (ACL) reconstruction. While various suspensory techniques have been described, the biomechanical profile of these constructs is largely undefined. To compare the biomechanics of suspensory techniques for soft tissue QT autograft fixation in an in vitro model of ACL reconstruction. Controlled laboratory study. Full-thickness QT grafts were harvested using a 9-mm graft blade. Adjustable-loop devices (ALDs) were secured to the graft (n = 6 per group) with a combination implant containing the ALD and suture tape-reinforced whipstitching (tape-reinforced [TR] group), tethered superficially to the graft with a whipstitch (onlay [OL] group), luggage-tagged through and around the graft (luggage tag [LT] group), or staggered behind superficial suturing (staggered [SG] group). Grafts were tested on an electromechanical testing machine following a validated in vitro reconstruction model of intraoperative workflow and postoperative ACL kinematics, cyclic loading, and load to failure. The TR group had significantly less postcyclic tension loss (mean, 24%) compared with the OL (56%; P = .002), LT (69%; P < .001), and SG (90%; P < .001) constructs. Cyclic elongation was below the 3.0-mm threshold defined as clinical failure for TR (1.6 mm), but not for OL (3.3 mm), LT (7.9 mm), and SG (11.3 mm). All constructs were within native ACL stiffness limits (220 ± 72 N/mm) without significant differences. Ultimate loads significantly exceeded a normal ACL loading limit of 454 N for TR (739 N; P = .023), OL (547 N; P = .020), and LT (769 N; P = .001), but not for SG (346 N; P = .236). The TR ALD construct demonstrated the most favorable time-zero biomechanical properties of modern soft tissue QT suspensory constructs, with 32% less tension loss and 52% less cyclic elongation versus the closest construct. Failure loading of all constructs was acceptable with respect to the native ACL except for the SG group, which had suboptimal ultimate load. TR ALD implants may protect soft tissue QT autografts before graft-bone healing in ACL reconstruction by minimizing time-zero laxity and fixation failure.

МЕХАНІЗМИ ПЛАСТИЧНОГО РУЙНУВАННЯ АРОК

The method of determining the limit load for double-hinged and hingeless arches of fixed and variable rigidity is considered. The calculation is performed using the limit equilibrium method. Arches under the influence of a vertical uniformly distributed load are considered. The cross section is taken in the form of a non-reinforced rectangle. The stress-strain state of an elastic-plastic material is described by the Prandtl diagram. The peculiarities of material deformation are that the yield limits in tension and compression are different. The determination of the limit load is based on taking into account only one factor - the bending moment. When a limiting moment occurs in the arch section, a plastic hinge is formed, which allows unlimited angular deformation without increasing the bending moment. When several plastic hinges are formed, the design diagram of the arch turns into a mechanism. Of course, this approach leads to inaccuracies in determining the limit load. However, at the first stage of the study, the task was to study in detail the features of the plastic mechanism of arch destruction. To study the limiting state of the arches, two methods were used - analytical calculation and numerical calculation using the finite element method. The use of two calculation methods allows you to control the results and increase their reliability. Using analytics, formulas were obtained to determine the limit load and coordinates of the sections where plastic hinges are formed. For arches of constant stiffness, formulas are written to determine the limit load, and for arches of variable stiffness, nonlinear equations are written, the solution of which allows us to find the limit load. For the numerical calculation, a simple method was used, when at each stage of the calculation the coordinate of the formation of the plastic hinge and the corresponding load were determined. The calculation program is written in APDL. As a result of the study, it was revealed that a hingeless arch, depending on the ratio of the lifting boom to the span, has three forms of plastic destruction, while a double-hinged arch has only one form of plastic destruction.

Evolution of Lubrication Characteristics of Double-Nut Ball Screws Based on an Efficient Surface Roughness Modeling Method

Abstract Accurate prediction of lubrication characteristics, specifically film thickness and pressure distribution, is pivotal for ensuring optimal performance in ball screws. Despite its significance, there is a notable dearth of studies investigating the evolution of lubrication characteristics resulting from the changing surface roughness over prolonged operation of ball screws. Furthermore, obtaining the surface roughness of ball screws poses a challenge due to the limited loading capacity of measurement instruments. Traditional methods involving cutting the screw for surface roughness measurement are impractical for continuous monitoring during extended operation. To address this issue, the present study introduces an efficient approach to model the surface roughness of the raceway in double-nut ball screws. A profilometer is employed to measure profile roughness along two directions (parallel and perpendicular to the rolling direction) without the need to cut the screw raceway. The 2D power spectral densities and height probability densities of profile roughness are calculated to model the surface roughness, and the synthesized data are utilized to solve the Reynolds equation. The simulation method is validated through friction torque tests, demonstrating a calculation accuracy exceeding 92%. The study further explores the evolution of film thickness and pressure distribution in double-nut ball screws during running-in and steady wear stages, revealing severe asperity contact in the two nuts. Additionally, variations in load ratio, friction coefficient, and film thickness ratio (λ) are investigated. Considering the load ratio and λ of the slave nut, it can be inferred that boundary lubrication persists in the two nuts throughout the operation.

Kinematic bearing capacity analysis of strip footings on reinforced soils using discretisation technique

The kinematic discretisation technique of upper bound limit analysis is adopted in this study to evaluate the limit load of a strip footing located on the soils reinforced with different geosynthetic layers. The reinforcement is assumed to withstand the tension but not bending moment. The failure model of the reinforced foundation soil is generated using the discretisation method, a ‘point by point’ technique. Two failure modes of the reinforcement, the tensile rupture and sliding, are considered in the analysis. This article proposed the formulas for the first time to evaluate the effect of soil friction angle φ on the ultimate bearing capacity and on the failure mechanism of foundation. The calculation results are given considering different reinforcement layers, which describe the impact of different reinforcement depth and length on the ultimate bearing capacity. The optimum positions of different reinforcement layers and the optimum reinforcement length are obtained. The bearing capacity ratios are also presented in figures combing impact of reinforcement depths, soil cohesion and friction angle. The present method was verified by the results reported in literature. The present method can provide a reference for the footing design on the reinforced soils.

Pengukuran Beban Kerja Mental Mahasiswa Pekerja Fakultas Ekonomi Dan Bisnis Universitas Muhammadiyah Gresik Menggunakan Metode Nasa-TLX

Background – Mental workload is the difference between the workload demands of a task and capacity. Mental workload is a human evaluation or assessment of the limits of attentional load while carrying out tasks optimally, which is influenced by the workload demands of a task and the worker's capacity to handle the task, especially for students who carry out work activities while studying. Therefore, it is necessary to examine how much mental workload is actually borne by student workers so that the negative impacts it causes can be minimized. Aim – To measure the mental workload of student workers at the Faculty of Economics and Business, Muhammadiyah University of Gresik using the NASA-TLX method Design / methodology / approach – The research approach used is Quantitative Descriptive. Quantitative data was obtained from the results of questionnaire responses from student workers at the Faculty of Economics and Business, Muhammadiyah University of Gresik regarding the level of mental workload using the NASA-TLX method. Findings – High mental workload can have a negative impact on a person's mental health, especially for students who work while studying. Mental workload is defined as the difference between task demands and an individual's capacity to handle the task, focusing more on the mental aspect than the physical. Students who work while studying often experience fatigue, lack of time to rest and socialize, and experience sleep disorders and stress which can reduce their academic and work performance. Therefore, it is important to measure and analyze the level of mental workload experienced by student workers in order to reduce its negative impact. The method used to measure mental workload is NASA-TLX (Task Load Index). Conclusion – Student workers at the Faculty of Economics and Business, Muhammadiyah University of Gresik experience a high mental workload, with the time demand indicator (Temporal Demand/TD) having the highest weight and the level of effort (Effort/EF) getting the highest score. The time requirement (TD) indicator most dominantly influences their mental workload, while the level of frustration (FR) has the lowest influence. Overall, their average mental workload score was in the high category, namely 77.64. Research implication – This research is aimed at students who are studying while working, with the aim of measuring the level of mental load that objects experience. The load in question is a high mental workload, with indicators of time requirements (Temporal Demand/TD), level of effort (Effort/EF) and indicators of time requirements (TD), as well as levels of frustration (Frustration/FR). Limitations – The limitations of this research only include the mental workload variable on the research object (student workers)

Collaborative effects of fuel properties and EGR on the efficiency improvement and load boundary extension of a medium-duty engine

EGR dilution combustion has problems such as weakened anti-knock capability at high load, slow combustion speed and poor combustion stability, which results in limitations in the thermal efficiency improvement and load boundary extension of medium-duty highly-downsized engines. It is necessary to combine EGR dilution and other measures to collaboratively control the in-cylinder thermodynamic state and combustion process. The experimental investigations in this study isolate the effect of the ethanol blending ratio in ethanol gasoline on the anti-knock performance, combustion performance and thermal efficiency, and verifies the potential of collaborative optimization of fuel properties and EGR in improving the thermal efficiency and extending the load boundary for a medium-duty highly-downsized engine. The results show that as the load increases, the improvement effect of increasing the blending ratio of ethanol in the anti-knock performance, combustion speed, and the turbine inlet temperature reduction will become more obvious. At high load, using E20 fuel can improve the EGR tolerance, advance the spark timing and CA50, and thus increase the BTE. As the speed decreases, the thermal efficiency improvement effect of E20 fuel gradually increases, and the improved load range extends. The collaborative optimization of E20 fuel and EGR can further extend the high thermal efficiency area of the engine. And the Max. achievable load is 0.11 MPa higher than that of E10, which effectively extends the upper load limit during the stoichiometric combustion.

Efficient compressed storage and fast reconstruction of large binary images using chain codes

AbstractLarge binary images are used in many modern applications of image processing. For instance, they serve as inputs or target masks for training machine learning (ML) models in computer vision and image segmentation. Storing large binary images in limited memory and loading them repeatedly on demand, which is common in ML, calls for efficient image encoding and decoding mechanisms. In the paper, we propose an encoding scheme for efficient compressed storage of large binary images based on chain codes, and introduce a new single-pass algorithm for fast parallel reconstruction of raster images from the encoded representation. We use three large real-life binary masks to test the efficiency of the proposed method, which were derived from vector layers of single-class objects – a building cadaster, a woody vegetation landscape feature map, and a road network map. We show that the masks encoded by the proposed method require significantly less storage space than standard lossless compression formats. We further compared the proposed method for mask reconstruction from chain codes with a recent state-of-the-art algorithm, and achieved between $$12\%$$ 12 % and $$33\%$$ 33 % faster reconstruction on test data.

Pilot-scale study of enhanced thermophilic anaerobic digestion of food waste with the addition of trace elements

Thermophilic anaerobic digestion (AD) offers many benefits for food waste treatment but is seldom adopted in industrial plants due to instability issue, particularly under higher loading conditions. This study thus conducted a 160-day continuous operation of a pilot-scale thermophilic AD system on-site. Results from the experiments showed that the system could operate under relatively lower loading but failed when the loading reached up to 5.69 kg·COD/(m3·d). Volatile fatty acids increased to 6000 mg/L at the corresponding hydraulic retention time of 15 days. Trace elements were then introduced, which restored higher process stability by reducing volatile fatty acids to 400 mg/L. The mass balance and materials decomposition resutls revealed the system’s strong resilience. Methanoculleus (92.52 %) and Methanomassiliicoccus (6.55 %) were the dominant methanogens, a phenomenon rarely observed in similar thermophilic systems. This system may tolerate more stressful conditions, as the loading limits had not been reached with the addition of trace elements.

A Minimalist Pathogen-Like Sugar Nanovaccine for Enhanced Cancer Immunotherapy.

Pathogen-mimicking nanoparticles have emerged at the forefront of vaccine delivery technology, offering potent immune activation and excellent biocompatibility. Among these innovative carriers, mannan, a critical component of yeast cell walls, shows promise as an exemplary vaccine carrier. Nevertheless, it faces challenges like unpredictable immunogenicity, rapid elimination, and limited antigen loading due to high water solubility. Herein, mannan with varying carbon chain ratios is innovatively modified, yielding a series of dodecyl chains modified mannan (Mann-C12). Through meticulous screening, a mannan variant with a 40% grafting ratio is pinpointed as the optimal vaccine carrier. Further RNA sequencing confirms that Mann-C12 exhibits desired immunostimulatory characteristics. Coupled with antigen peptides, Mann-C12/OVA257-280 nanovaccine initiates the maturation of antigen-presenting cells by activating the TLR4 and Dectin-2 pathways, significantly boosting antigen utilization and sparking antigen-specific immune responses. In vivo, experiments utilizing the B16-OVA tumor model underscore the exceptional preventive capabilities of Mann-C12/OVA257-280. Notably, when combined with immune checkpoint blockade therapy, it displays a profound synergistic effect, leading to marked inhibition of tumor growth. Thus, the work has yielded a pathogen-like nanovaccine that is both simple to prepare and highly effective, underscoring the vast potential of mannan-modified nanovaccines in the realm of cancer immunotherapy.

The Synergistic Potential of Hydrogel Microneedles and Nanomaterials: Breaking Barriers in Transdermal Therapy.

The stratum corneum, which acts as a strong barrier against external agents, presents a significant challenge to transdermal drug delivery. In this regard, microneedle (MN) patches, designed as modern systems for drug delivery via permeation through the skin with the ability to pass through the stratum corneum, are known to be convenient, painless, and effective. In fact, MN have shown significant breakthroughs in transdermal drug delivery, and among the various types, hydrogel MN (HMNs) have demonstrated desirable inherent properties. Despite advancements, issues such as limited loading capacity, uncontrolled drug release rates, and non-uniform therapeutic approaches persist. Conversely, nanomaterials (NMs) have shown significant promise in medical applications, however, their efficacy and applicability are constrained by challenges including poor stability, low bioavailability, limited payload capacity, and rapid clearance by the immune system. Incorporation of NMs within HMNs offers new prospects to address the challenges associated with HMNs and NMs. This combination can provide a promising field of research for improved and effective delivery of therapeutic agents and mitigate certain adverse effects, addressing current clinical concerns. The current review highlights the use of NMs in HMNs for various therapeutic and diagnostic applications.

Steam Reforming of Tar Impurities from Biomass Gasification with Ni-Co/Mg(Al)O Catalysts—Operating Parameter Effects

The elimination of tar impurities from biomass gasification by catalytic steam reforming can provide clean syngas for downstream biofuel synthesis (Fischer–Tropsch). The effects of key operating parameters in CH4/tar steam reforming were investigated. Ni-Co/Mg(Al)O catalyst performance was tested at model conditions (10/35/25/25/5 wt% CH4/H2/CO/CO2/N2), changing the temperature (650–800 °C), steam-to-carbon ratio (2–5), tar loading (10–30 g/Nm3), and tar composition (toluene, 1-methylenaphthalene, and phenol). Complete tar elimination was achieved under all conditions, at the expense of catalyst deactivation by coke formation. Post-operation coke characterization was obtained with TPO-MS, Raman spectroscopy, and STEM analysis, providing vital insight into coke morphology and location. Critical low-temperature and high-tar loading limits were identified, where rapid deactivation was accompanied by increasing amounts of hard coke species. A coke classification scheme is proposed, including strongly adsorbed surface carbon species (soft coke A), initial scattered carbon filaments (hard coke B1.1), filament clusters and fused filaments (B2), and strongly deactivating bulk encapsulating coke (B3), formed through progressive filament cluster graphitization. High-molecular-weight tar was found to enhance the formation of strongly deactivating metal-particle-encapsulating coke (B1.2). The results contribute to the understanding of coke formation in the presence of biomass gasification tar impurities.