Loading Technique Research Articles

Dynamic Behavior of Concrete: A Review

Abstract: Concrete properties are the most essential and critical physical material property when reinforced concrete structures are designed. Considering potential catastrophic accidents, testing of dynamic mechanical properties of concrete is one of the most urgent stages of development. A large number of scientific experiments have shown that the dynamic mechanical properties of concrete are influenced by strain rate. This paper covers the existed researches on the dynamic mechanical characteristics of concrete. Review of the relationship between concrete's dynamic compressive strength, deformation properties, elastic modulus, and energy dissipation capacity with strain rate. The results may vary depending on the loading technique, test apparatus, specimen size, and other variables. The study of dynamic tensile behavior of concrete was uncommon due to the limitations of experimental tools and testing methods. The data returns so far have been inconsistent and even at conflict with one another. The most widely used test techniques to investigate the dynamic tensile behavior of concrete are the direct tensile test, splitting test, bending test and spalling test.

Research Progress in the Flight Characteristics of Flyers Driven by Different Technologies

Flyers driven by various technologies have been widely used as effective shock loading techniques in the ignition of energetic materials, space debris impact modeling, equation of state measurement, etc. However, their flying characteristics have the greatest influence on application reliability. The flying velocity, as well as the flyer’s planarity and integrity, are crucial characteristics. Therefore, mainstream flyer-driving technologies are examined in this study, and research progress in investigation approaches on flyer velocity and morphology are reviewed. Furthermore, for each flyer-driving technique, the affecting factors of flyer velocity and morphology are summarized. Current research deficiencies are highlighted, and future research directions are discussed, including the parallel coupling of various driving principles, quantitative characterizations of the flyer’s planarity and integrity, and the physical model matching the flying process.

Theoretical investigation of the mechanical properties of single- and multi-layer CH3NH3XI3 (X = Pb, Sn, Mn) perovskites at various temperatures and pressures

The mechanical qualities of single – and multi-layer CH3NH3XI3 (X = Pb, Sn, Mn) perovskite structures have been computed using the LAMMPS programme via the molecular dynamics’ method. The LAMMPS analysis code is the keystone for computing mechanical characteristics in simulations. The stress–strain curves of the simulated atomic structures are offered for tests in the X and Y directions. The stress–strain curves were significantly computed by employing the loading technique and the deform command during the computational tests. Mechanical data was retrieved by inducing deformation in the simulated structures. The stress–strain curves for the single – (SL) and the multi-layer (ML) CH3NH3XI3 at various temperature and pressure values in the X and Y directions were also produced and compared, after applying a maximum stress (ultimate strength) using a load. Molecular dynamics (MD) simulations using LAMMPS software showed that layered perovskite materials possess high flexibility compared to the non-layered perovskite materials, which is essential in perovskite solar cells. The studied atomic structures thus provided the significant mechanical properties for designing proficient perovskite solar cells via the MD simulation.

Ketoprofen-Based Polymer-Drug Nanoparticles Provide Anti-Inflammatory Properties to HA/Collagen Hydrogels.

Current limitations of wound dressings for treating chronic wounds require the development of novel approaches. One of these is the immune-centered approach, which aims to restore the pro-regenerative and anti-inflammatory properties of macrophages. Under inflammatory conditions, ketoprofen nanoparticles (KT NPs) can reduce pro-inflammatory markers of macrophages and increase anti-inflammatory cytokines. To assess their suitability as part of wound dressings, these NPs were combined with hyaluronan (HA)/collagen-based hydro- (HGs) and cryogels (CGs). Different HA and NP concentrations and loading techniques for NP incorporation were used. The NP release, gel morphology, and mechanical properties were studied. Generally, colonialization of the gels with macrophages resulted in high cell viability and proliferation. Furthermore, direct contact of the NPs to the cells reduced the level of nitric oxide (NO). The formation of multinucleated cells on the gels was low and further decreased by the NPs. For the HGs that produced the highest reduction in NO, extended ELISA studies showed reduced levels of the pro-inflammatory markers PGE2, IL-12 p40, TNF-α, and IL-6. Thus, HA/collagen-based gels containing KT NPs may represent a novel therapeutic approach for treating chronic wounds. Whether effects observed in vitro translate into a favorable profile on skin regeneration in vivo will require rigorous testing.

Biomimetic and Biologically Originated Nanoparticles for Drug Delivery Applications: a brief overview and update

Biomimetic and biologically originating nanoparticles are an exciting new form of drug delivery system. Examples of biologically originating nanoparticles include exosomes and other extracellular vesicles, lipoproteins, ferritins, and virus-like nanoparticles. These nanoparticles can range anywhere from 5 nm up to 1000 nm and can come in different configurations depending on the nature of the nanoparticle. Various types of drugs can be loaded into these nanoparticles including hydrophobic, hydrophilic, small molecule, and nucleic acid drugs. Specific loading techniques have been developed for each nanoparticle specie. These naturally occurring nanoparticles all undergo a similar processing process, in which they are collected, purified, and functionalized for use as drug delivery systems. The scale and relative availability within our own bodies presents a significant difficulty to using biological nanoparticles for commercial applications. Using recombinant nanoparticles, produced by bacterium and other microorganisms, is a viable alternative to human derived nanoparticles, but does require more processing to become functional. Although there are many advantages to using biologically originating nanoparticles for drug delivery, such as high target specificity, great biocompatibility, and biodegradability, they are limited by their stability, scalability, and safety as they are largely unstudied compared to current drug delivery models. Further work must be done to fully characterize and fully realize the potential of these nanoparticles.

Soluplus-stabilized 5-fluorouracil-entrapped niosomal formulations prepared via active and passive loading techniques: comparative physico-chemical evaluation

The objective of this study was to prepare and conduct a comparative analysis on 5-fluorouracil (5FU) niosomes stabilized with or without Soluplus, utilizing, respectively, passive loading and active loading techniques. Cholesterol was combined with Span 40 and Tween 40 surfactants to prepare several niosomal formulations by either passive or active methods. Encapsulation efficiency (EE%), loading capacity (LC), mean particle sizes, polydispersity indices (PDI), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), pH stability, and in vitro drug release in bio relevant media of pH 1.2, 6.8, and 7.4 were employed to evaluate the formulations. Batches made using the active loading approach (B1-B5) demonstrated higher entrapment efficiency (25–40%) (p ˂ 0.05) than those made using the passive loading method (20%) (with the exception of batch A1). In comparison to niosomes made using the passive loading method, the active loading methodology produced niosomes with a lower PDI (˂ 0.25) and particle size (˂ 70 nm). SEM revealed spherical and discrete vesicles for the Soluplus stabilized niosomes. Both approaches produced niosomes with prominent hydrogen bonding as observed in the FTIR study. The formulations were stable and sustained drug release, but the active loading strategy imparted a more sustained release pattern than the passively loaded one. Soluplus stabilized niosomes demonstrated higher (p ˂ 0.05) drug release (60–70%) in all release media. Based on the production of smaller particle sizes and narrower size distribution, the active loading strategy may be a more effective way to load hydrophilic medicines such as 5FU into niosomes.

Potential of Mesenchymal Stromal Cell-Derived Extracellular Vesicles as Natural Nanocarriers: Concise Review

Intercellular communication, through direct and indirect cell contact, is mandatory in multicellular organisms. These last years, the microenvironment, and in particular, transfer by extracellular vesicles (EVs), has emerged as a new communication mechanism. Different biological fluids and cell types are common sources of EVs. EVs play different roles, acting as signalosomes, biomarkers, and therapeutic agents. As therapeutic agents, MSC-derived EVs display numerous advantages: they are biocompatible, non-immunogenic, and stable in circulation, and they are able to cross biological barriers. Furthermore, EVs have a great potential for drug delivery. Different EV isolation protocols and loading methods have been tested and compared. Published and ongoing clinical trials, and numerous preclinical studies indicate that EVs are safe and well tolerated. Moreover, the latest studies suggest their applications as nanocarriers. The current review will describe the potential for MSC-derived EVs as drug delivery systems (DDS) in disease treatment, and their advantages. Thereafter, we will outline the different EV isolation methods and loading techniques, and analyze relevant preclinical studies. Finally, we will describe ongoing and published clinical studies. These elements will outline the benefits of MSC-derived EV DDS over several aspects.

Construction of nano slow-release systems for antibacterial active substances and its applications: A comprehensive review.

At present, nano-carrier materials with antibacterial activity are of great significance. Due to the widespread resistance of many pathogenic microorganisms, it has seriously threatened human health. The natural antimicrobial substances extracted from fruits and vegetables can significantly improve their stability combined with nano-carrier materials. The resistance of pathogenic microorganisms will be substantially reduced, greatly enhancing the effect of active antimicrobial substances. Nanotechnology has excellent research prospects in the food industry, antibacterial preservation, food additives, food packaging, and other fields. This paper introduces nano-carrier materials and preparation techniques for loading and encapsulating active antibacterial substances in detail by constructing a nano-release system for active antibacterial substances. The antibacterial effect can be achieved by protecting them from adverse external conditions and destroying the membrane of pathogenic microorganisms. The mechanism of the slow release of the bacteriostatic active substance is also described. The mechanism of carrier loading and release is mainly through non-covalent forces between the bacteriostatic active substance and the carrier material, such as hydrogen bonding, π-π stacking, van der Waals forces, electrostatic interactions, etc., as well as the loading and adsorption of the bacteriostatic active substance by the chemical assembly. Finally, its wide application in food and medicine is introduced. It is hoped to provide a theoretical basis and technical support for the efficient utilization and product development of bacteriostatic active substances.

SG-APSIC1130: Zero wet pack Pimporn Sirikraiwattanawong, Thailand

Objectives: We noted moisture in Thompson retractor sets after steam sterilization in our hospital. Moisture can cause severe problems leading to potentially contaminated instruments that carry infection risk to patients and cause procedure delays, wasted time and effort, greater workload, and higher costs. We sought to reduce the number of retractor sets with moisture to zero. Methods: The central sterile supply (CSS) team discussed the cause of the problem. We hypothesized that temperature difference between the sterilizer chamber and inside the container might create condensation and thus moisture in the final surgical set. We collected and analyzed data and proposed an experiment to improve the sterilization process. We performed a trial of sterilization process improvements pertaining to proper loading technique and the packaging process. We also evaluated the appropriate drying time for rigid containers. We then rearranged the process and adjusted the cooling time from 30 to 60 minutes after steaming. Results: Moisture in Thompson retractor packs occurred because of thicker, rigid containers. We removed the previous type of lining material to separately steam the rigid surgical instrument, and we extended the cooling time to 60 minutes. We updated standard operation procedures and continued to monitor and re-evaluate the process. Conclusions: We identified the primary cause of moisture in Thompson retractor sets after steam sterilization. We illustrated that avoiding sterilizer overload, avoiding contact with fabric wrapping materials, and proper cooling time kept the pack moisture free. Occurrences of moisture in surgical packs after sterilization should be reported and handled efficiently by CSS personnel to preserve quality and avoid waste.

Design Approach for Pattern-Reconfigurable Patch Antenna Without Extra Feeding Networks

In this communication, an efficient approach with multiple loading techniques is proposed to design a low profile, single-fed, pattern reconfigurable patch antenna with broadside and dual-beam radiation patterns. Initially, a transmission-line model is developed to theoretically investigate the resonant frequency of a rectangular patch antenna with radiation efficiency ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\eta _{r}$ </tex-math></inline-formula> ) into consideration as well. It is revealed that the frequency overlap in the two states without significantly sacrificing <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\eta _{r}$ </tex-math></inline-formula> can be achieved by properly loading shorting pins and open-ended stubs. Besides, the two center-loaded elements, i.e., a shunt capacitor and a series inductor, are also studied for demonstration of their unique effects on impedance matching for both states or operating modes. Then, a design guideline is summarized based on the theoretical analysis. Following the developed guideline, two examples working at the same operating frequency of 2.45 GHz are designed, fabricated, and tested. Measured gains of 9.6 (8.7) and 5.6 (5.3 dBi) of antenna example A (example B) are obtained for broadside and dual-beam modes, respectively. The measured and simulated results are observed in good agreement, thereby demonstrating the validity of the proposed scheme. The merits of low profile, high gain, and no need of extra feeding networks make the proposed antennas good candidates for modern communication systems.

Innovative design of bio-functional Persian gum-based edible films by incorporating crocin and cinnamaldehyde: Free versus single and double emulsion fabrication techniques

The objective of this research was to fabricate a new generation of bio-functional Persian gum-based films via the co-delivery of crocin and cinnamaldehyde. Different loading strategies using single W/O and O/W emulsions and W 1 /O/W 2 double emulsions were used to find how the distribution of bioactives in the film suspension can modify their physicochemical and biological properties compared to those prepared with the free forms of bioactives. The incorporation of emulsion structures significantly decreased the surface tension of film-forming solutions, but their viscosity remained relatively constant. The good compatibility between Persian gum and cinnamaldehyde/crocin was confirmed by FTIR and XRD. The optical, mechanical, and microstructural attributes of the films were more affected by the incorporation of the free form of bioactives. The UV–Vis light barrier property and hydrophobicity of the film were improved after incorporating single and double emulsions. However, the greater stability of bioactives within double emulsion against different pH (2 and 7) and temperatures (25 and 75 °C) produced more superior antibacterial and antioxidant activities. Furthermore, the homogenous distribution of double emulsion in the film matrix led to more resistant and extensible films. • Persian gum-based film was fortified with co-delivery of crocin and cinnamaldehyde. • Comparison was made between free and single and double emulsions loading techniques. • Mechanical and optical properties were more affected by free forms of bioactives. • Double emulsion strategy led to superior antibacterial and antioxidant activities. • Emulsion-based films were transparent but with high UV/Vis barrier properties.

Exploring the Joint Association of Road Traffic Noise and Air Quality with Hypertension Using QGIS.

There is growing evidence linking exposure to air pollution and traffic noise with hypertension. The aim of this study was to examine the associations of registered hypertension cases and hypertension rate with exposure to air pollution and road noise. In this cross-sectional study, we linked the information from the NHS Scotland database of 776,579 hypertension patients' registrations and rates per 13.80 people at the Scottish NHS Board, HSCP, Cluster, and GP practice levels. Based on the geospatial attributes, the data on residential areas were added by modelling annual average air pollutant concentrations, including particulate matter (PM10 and PM2.5), nitrogen dioxide (NO2), and road-traffic noise at different frequency components (Lden). The relationships between exposure to road noise, air pollution, and hypertension were examined using multiple regression and multivariate analysis. Traffic noise and air pollution at various frequency components positively and negatively predicted registered hypertension cases and hypertension rate. Based on the canonical loading technique, the variance explained by the canonical independent variable at a canonical correlation of 0.342 is 89%. There is a significant correlation between joint air pollution and noise at different frequency components and combined registered hypertension cases and hypertension rate. Exploring the combined effects of the two environmental exposures and the joint modelling of noise and air pollutants with hypertension in geospatial views provides an opportunity to integrate environmental and health data to support spatial assessment strategies in public and environmental health.

Unexpected Factors Affecting the Kinetics of Guest Molecule Release from Investigation of Binary Chemical Systems Trapped in a Single Void of Mesoporous Silica Particles.

In this work, we present results for loading of well-defined binary systems (cocrystal, solid solution) and untreated materials (physical mixtures) into the voids of MCM-41 mesoporous silica particles employing three different filling methods. The applied techniques belong to the group of "wet methods" (diffusion supported loading - DiSupLo) and "solvent-free methods" (mechanical ball-mill loading - MeLo, thermal solvent free - TSF). As probes for testing the guest1-guest2 interactions inside the MCM-41 pores we employed the benzoic acid (BA), perfluorobenzoic acid (PFBA), and 4-fluorobenzoic acid (4-FBA). The guests intermolecular contacts and phase changes were monitored employing magic angle spinning (MAS) NMR Spectroscopy techniques and powder X-ray diffraction (PXRD). Since mesoporous silica materials are commonly used in drug delivery system research, special attention has been paid to factors affecting guest release kinetics. It has been proven that not only the content and composition of binary systems, but also the loading technique have a strong impact on the rate of guests release. Innovative methods of visualizing differences in release kinetics are presented.

Short Term Load Forecasting for Smart Grids Using Apache Spark and a Modified Transformer Model

Smart grid is an advanced electrical grid that enables more efficient distribution of electricity. It counters many of the problems presented by renewable energy sources such as variability in production through techniques like load forecasting and dynamic pricing. Smart grid generates massive amounts of data through smart meters, this data is used to forecast future load to adjust distribution. To process all this data, big data analysis is necessary. Most existing schemes use Apache Hadoop for big data processing and various techniques for load forecasting that include methods based on statistical theory, machine learning and deep learning. This paper proposes using Apache Spark for big data analysis and a modified version of the transformer model for forecasting load profiles of households. The modified transformer model has been tested against several state-of-the-art machine learning models. The proposed scheme was tested against several baseline and state-of-the-art machine learning models and evaluated in terms of the RMSE, MAE, MedAE and R2 scores. The obtained results show that the proposed model has better performance in terms of RMSE and R2 which are the preferred metrics when evaluating a regression model on data with a large number of outliers.

Robust fully controlled nanometer liquid layers for high resolution liquid-cell electron microscopy.

Liquid cell electron microscopy (LCEM) has long suffered from irreproducibility and its inability to confer high-quality images over a wide field of view. LCEM demands the encapsulation of the in-liquid sample between two ultrathin membranes (windows). In the vacuum environment of the electron microscope, the windows bulge, drastically reducing the achievable resolution and the usable viewing region. Herein, we introduce a shape-engineered nanofluidic cell architecture and an air-free drop-casting sample loading technique, which combined, provide robust bulgeless imaging conditions. We demonstrate the capabilities of our stationary approach through the study of in-liquid model samples and quantitative measurements of the liquid layer thickness. The presented LCEM method confers high throughput, lattice resolution across the complete viewing window, and sufficient contrast for the observation of unstained liposomes, paving the way to high-resolution movies of biospecimens in their near native environment.

A Review on Fatigue Mechanisms and Approaches for Hard metals

In this study, fatigue lifemechanisms and approaches for hard metals commonly known as cemented carbides that are supported by literature are reviewed on development of fatigue life technology methods. The hard metals materials are mainly used in engineering systems and failure due to fatigue is common phenomenon in engineering materials.The fatigue crack growth therefore plays very important role towards fatigue failure mechanisms and this remains a setback to engineering fraternity as far as usage of these hard metals are concerned. The fatigue process occurs when a material is subjected to fluctuating stress and strain, this may lead to failure when it accumulates loading due to cumulative damage, multiaxial and variable loading. The Crack initiation growth and micro-mechanisms of damage during fatigue growth with optimization of fatigue life technology approaches and fracture growth resistance are main focus of this review article. Thee review of this paper is based on fatigue life mechanisms adoption methodsfor hard metals with novelty of Crack Tip opening displacement technologyand its implementation in various systems will ought to assist technologists in extraordinary broad programs.In conclusion cumulative damage, fatigue mechanisms, multiaxial amplitude loading and fatigue crack growth mechanics techniques are important andan appropriate fatigue life technology mechanisms methods. Eventually these review article will give potential information on fatigue life technology adoption methods and this helps future researcher and technologists to consider the fatigue life models and these ideas will impact on future application of fatigue life failure mechanisms.

Long-Term Culture and Monitoring of Isolated Caenorhabditis elegans on Solid Media in Multi-Well Devices.

The nematode Caenorhabditis elegans is among the most common model systems used in aging research owing to its simple and inexpensive culture techniques, rapid reproduction cycle (~3 days), short lifespan (~3 weeks), and numerous available tools for genetic manipulation and molecular analysis. The most common approach for conducting aging studies in C. elegans, including survival analysis, involves culturing populations of tens to hundreds of animals together on solid nematode growth media (NGM) in Petri plates. While this approach gathers data on a population of animals, most protocols do not track individual animals over time. Presented here is an optimized protocol for the long-term culturing of individual animals on microfabricated polydimethylsiloxane (PDMS) devices called WorMotels. Each device allows up to 240 animals to be cultured in small wells containing NGM, with each well isolated by a copper sulfate-containing moat that prevents the animals from fleeing. Building on the original WorMotel description, this paper provides a detailed protocol for molding, preparing, and populating each device, with descriptions of common technical complications and advice for troubleshooting. Within this protocol are techniques for the consistent loading of small-volume NGM, the consistent drying of both the NGM and bacterial food, options for delivering pharmacological interventions, instructions for and practical limitations to reusing PDMS devices, and tips for minimizing desiccation, even in low-humidity environments. This technique allows the longitudinal monitoring of various physiological parameters, including stimulated activity, unstimulated activity, body size, movement geometry, healthspan, and survival, in an environment similar to the standard technique for group culture on solid media in Petri plates. This method is compatible with high-throughput data collection when used in conjunction with automated microscopy and analysis software. Finally, the limitations of this technique are discussed, as well as a comparison of this approach to a recently developed method that uses microtrays to culture isolated nematodes on solid media.

Load-bearing analysis of polymer nanocomposite gears using a temperature-based step loading technique: Experimental and numerical study

The load-bearing characteristic of polyoxymethylene (POM)/carbon black (CB)/CaCO3 ternary nanocomposite gears were assessed using a temperature-based step loading approach. An online temperature measuring system was integrated into the gear test rig to continuously measure the gears’ bulk temperature. Dynamic mechanical thermal analysis (DMTA) was performed to explore a correlation between the viscoelastic characteristics, failure, and wear behavior of nanocomposite gears. The step loading test results showed that the load-bearing capacity was incremented from 7 Nm for pure POM to 10 Nm for POM/CB/3CaCO3 ternary nanocomposite gear. The finite element analysis of gears indicated that the maximum contact stress was different for those with similar critical torque. It was suggested that the maximum contact stress could complement the step loading technique in defining the load-carrying capacity of polymer-based gears. The failure analysis indicated the impediment of tooth cracking and thermal bending in ternary nanocomposite gears. The scanning electron microscopy (SEM) micrographs showed a much smoother tooth worn surface with minor traces of surface cracks and plastic flow for ternary nanocomposites, assigned to the promoted wear resistance, elastic response, and lower hysteretic self-heating due to the synergetic reinforcing effects of CB and nano-CaCO3.

Consolidation Assessment of Marine Clay Using Electrokinetic Coupled with Constant Load

In Marine clays, the consolidation phenomenon is a significant issue of concern. For this, an innovative electrokinetic consolidation method was adopted by coupling the conventional consolidation technique with a constant voltage gradient. A series of tests were performed on reconstituted marine clay samples for constant loading intensity of 4kg/cm² coupled with a constant DC voltage of 2, 4 and 6V. Various parameters such as deformation, void ratio, current, pH, voltage and moisture content were continuously monitored to compare with test results of conventional Incremental loading (IL) and constant loading (CL) techniques. In the case of electrokinetic (EK) coupled loading, with an increase in voltage gradient, the values obtained for voltage and current were also increased to maximum and then decreased afterwards. Microfabric changes were also visible in soils collected at anode and cathode, which were evidenced with the images of scanning electron microscopy (SEM) data obtained before and after EK consolidation tests when compared with original marine clay. The constant loading intensity of 4kg/cm² with a 4V electric gradient resulted in higher compression and better consolidation characteristics than other loading conditions.

Gain and Bandwidth Improvement Studies of Millimeter Wave Periodically Dielectric Loaded Gyro-Twystron Amplifier

In this article, the spurious oscillations in the output section of gyro-twystron have been analyzed and the design and modeling of its various subassemblies also been presented. The periodic dielectric loading (PDL) technique has been adapted in the output waveguide section to improve the device gain by suppressing the backward wave oscillations (BWOs). Further, to improve the performance of the amplifier all the cavities were staggered tuned. The particle-in-cell (PIC) simulation of the present PDL gyro-twystron predicted an RF output power of ~120 kW in the fundamental TE01 mode at 94 GHz. The conversion efficiency, 3-dB bandwidth, and saturated gain were calculated as ~34%, ~2.2 GHz, and ~51 dB, respectively. A triode magnetron injection gun (MIG) was designed for 60 kV and 6 A gyrating electron beam and optimized for the velocity spread of ~2.2% with a velocity ratio of 1.6. A single-stage depressed (SSD) collector has also been designed to enhance the efficiency of the amplifier to ~57%. A double-disk window was designed and optimized for the broader bandwidth of ~8 GHz.