Dependent Behavior Research Articles

The nature of crystal facet effect of TiO2-supported Pd/Pt catalysts on selective hydrogenation of cinnamaldehyde: electron transfer process promoted by interfacial oxygen species.

Supported noble metal nanocatalysts typically exhibit strong crystal plane dependent catalytic behavior, but their working mechanism is still unclear. Herein, using anatase TiO2 with well-exposed crystal facets of {101}, {100} and {001} as a prototype support, Pd- and Pt-based supported TiO2 nanocatalysts (TiO2-Pd and TiO2-Pt) were prepared by chemical reduction with NaBH4 as reducer, and they showed a distinct metal-dependent crystal facet effect in the selective hydrogenation of cinamaldehyde (CAL). For Pd-based nanocatalysts, most Pd species on the {100} plane of TiO2 are present in the oxidized form with positive charges and unexpectedly show higher reactivity than the Pd species in the zero-valence state on the {101} and {001} planes. On the contrary, Pt species on all three crystal planes of TiO2 show zero-valence state, with relatively low conversion, but much better selectivity for hydrogenation of a CO bond than Pd-based catalysts. Well-designed experiments manipulating the stability and type of surface oxygen species confirmed that the essence of the crystal facet effect of the catalyst support actually creates a unique nanoconfined interface at the molecular level to construct a surface p-band intermediate state (PBIS), which provides a new alternative channel for surface electron transfer and consequently accelerates the reaction kinetics.

Cyclic strain rate dependent behaviour of Alloy 617

This paper investigates the effect of strain rate on the properties of Alloy 617 under low-cycle fatigue (LCF) in room temperature (RT). The LCF life properties and the damage mechanism are studied for this Alloy over a range of strain rate (5E-4 ∼ 1E-2 s−1) under fully-reversed controlled total strain range of 1.2%. It is found that LCF life of Alloy 617 is strongly influenced by the time-dependent mechanism, in terms of slow strain rate test (SSRT). The relationship between total strain, plastic strain, and time to failure with strain rates are established and expressed by means of power law function to describe the fatigue life. Metallography examination is carried out on the fractured specimens with the help of electron microscope and the fractography is discussed to distinguish the effect of SSRT on the physical damage characteristic under LCF loadings.

Motivational orientations of students towards internet dependent behavior and measures for its prevention.

Aim: The aim is to study the motivation of students towards Internet dependent behavior and develop practical recommendations for improving a set of measures for its prevention. Materials and Methods: The research involved 154 students of the National Academy of Internal Affairs. Research methods: analysis and generalization of literature sources, questionnaire, statistical methods. Results: The priority motives of students who manifest Internet dependence behavior were identif i ed. The motivational orientations of students determine their systematic stay in the virtual environment and include, first of all, compliance with modern world trends; accessibility of content; the need for recognition of personal results by other users; satisfaction with virtual communication with the social environment. Conclusions: The practical recommendations for improving a set of measures to counteract the spread of Internet dependence among students were developed. Overcoming Internet dependence involves influencing a person to change his or her motivational and value as well as communication spheres. Prevention of Internet dependence involves public health professionals conducting awareness-raising as well as psychological and correctional work with the most vulnerable categories of people.

Parenting Patterns in the Formation of Children's Behavior (Case Study in Children with ADHD)

Parents play a crucial role as the primary caregivers and educators of children, each employing their unique parenting style. This research aimed to elucidate the parenting patterns employed by parents in influencing the behavior of children with Attention Deficit Hyperactivity Disorder (ADHD). The study utilized a qualitative research method with a case study approach, focusing on children diagnosed with ADHD. The data collection process incorporated interviews, observations, and documentary studies. Rigorous data validation is achieved through source triangulation and technique triangulation. The interactive analysis model involves data reduction, presentation, and subsequent conclusion drawing. The research findings reveal that parents of children with ADHD adopt both permissive and authoritarian parenting patterns. Observable parenting behaviors include allowing excessive freedom, maintaining a constant belief in being right, and consistently acquiescing to the desires of the ADHD child. These parenting patterns contribute to the development of dependent behaviors in children, manifesting as an unwillingness to compromise, emotional instability, and involvement in actions detrimental to others.

Numerical implementation of the hypoplastic model for SPH analysis of soil structure development in extremely large deformation

The extremely large deformation of soil is a significant challenge due to the dynamic changes in soil structure, but it is poorly understood owing to inadequate effective numerical methods. This paper presents a numerical method for analysing the responses of sand-like granular soil undergoing extremely large deformation. The proposed method utilizes the Smoothed Particle Hydrodynamics (SPH) technique, which is a meshfree particle-based approach capable of circumventing the computational difficulties associated with mesh distortion. The Gudehus-Bauer (G-B) hypoplastic model, which can capture the pressure- and density- dependent mechanical behaviour of granular soil, is implemented into the in-house developed SPH code. Concerning the characteristics of large deformation, the Green-Naghdi rate is applied in this study to achieve objective stress integration. An adaptive explicit stress integration scheme, termed Modified Euler automatic Substepping with Error Control (M-E-SEC) is utilized to handle the time integration of the SPH equation system. Additionally, a stability correction method is introduced to suppress the breakdown problem that occurs at low-stress states. The effectiveness of the proposed method is validated by experimental data. Furthermore, several numerical examples are presented to elucidate the evolution of shear band structures in granular soils subject to extremely large deformation levels.

Digital Composition Control of Cobalt Nickel Oxides by ALD for the Oxygen Evolution Reaction

Anion exchange membrane water electrolysis is a potentially low-cost and sustainable technology for renewable-energy driven hydrogen production. Realisation of its full potential relies on the development of cost-effective, earth-abundant OER electrocatalysts alternatives to the state-of-the art noble metal oxides1. Ternary transition metal oxides, such as cobalt nickel oxides, are promising candidates due to their excellent alkali resistance in combination with remarkable catalytic activities. The latter relate to their tuneable oxidation states and variation in coordination of their metal centres. These correlations can be properly investigated when precise control over the layer chemical composition is attained. Atomic layer deposition (ALD) is widely acknowledged to deliver control over film uniformity, thickness and conformality, as well as film chemical composition due to the self-limiting nature of its surface reactions.In this study, an ALD supercycle process based on cobalt cyclopentadienyl (CoCp2) and nickel methylcyclopentadienyl (Ni(MeCp)2) precursors and an oxygen plasma co-reactant has been developed2 to investigate the influence of chemical composition and crystallographic properties of cobalt nickel oxide thin films on their electrocatalytic OER performance. Deposition of ~20 nm binary nickel oxide and cobalt oxide results in the growth of polycrystalline films of the rock-salt and spinel phase, respectively. Ternary cobalt nickel oxide films with various ratios can be deposited uniformly, as indicated by energy dispersive x-ray spectroscopy mapping. The mixed oxides display a transition from the +2 oxidation state-based pure rock-salt phase (<25 at.% Co) to the spinel phase consisting of mixed +2/+3 oxidation states (>75% at.% Co) upon increasing Co at.% as verified by electron diffraction (figure a) and x-ray photoelectron spectroscopy (XPS). XPS furthermore reveals a linear increase in the Ni3+-to-Ni2+ ratio with increasing Co at.%, which indicates that an inverse spinel structure is formed. The formation of a Ni3+-rich inverse spinel cobalt nickel oxide between 55 and 75 at.% Co facilitates the formation of a semi-metallic state (102 S/cm) as opposed to the poorly conductive binary oxides (10-3 S/cm and 10-2 S/cm for NiO and Co3O4, respectively).Cyclic voltammetry (CV) measurements in 1M KOH, reveal chemical composition dependent activation behaviour (figure b). Continuous activation behaviour is observed for rock-salt phase films, whilst increment of the Co at.% results in reduced film activation until virtually no activation of the spinel phase films is observed. The activation of the nickel-rich film is accompanied by irreversible redox changes from the +2 to +3 oxidation state as indicated by the integrated non-catalytic wave. Post CV XPS analysis confirms the transition from Co2+ and Ni2+ oxidation states to Co3+ and Ni3+. The formation of an (oxy)hydroxide state is observed for the rock-salt dominated films, whilst oxidation states characteristic of a spinel- like oxide structure are observed for the cobalt-rich films. No changes in the transition metal ratios are observed after activation. Scanning electron microscopy images furthermore reveal that the transformation of the Ni-rich films is accompanied by surface restructuring. These results indicate that initial composition can significantly influence the electrocatalytic performance of ternary oxides and therefore highlight the importance of techniques such as atomic layer deposition to study their complex behaviour. 1Xu et al., Energy Chem., 4 (2022) 100087 2van Limpt et al., J. Vac. Sci. Technol. A, 41 (2023) 032407 This work has been carried out within the SCALE project (NWA.1237.18.001) funded jointly by the Netherlands Organization for Scientific Research. Authors would like to thank the co-founders of the project ISPT, Syngaschem, VecoPrecision and Vsparticle and international partners Toyota Motor Europe and FORTH institute. Figure:(a) ALD deposited cobalt nickel oxide film show a transition from the +2 oxidation state-based rock-salt phase (NiO) to the spinel structure consisting of mixed +2/+3 oxidation states (Co3O4) upon tuning the chemical composition as identified by electron diffraction. (b) This significantly affects the OER-electrocatalytic performance and activation of the films as represented by the current density at 1.8V vs RHE over 500 CV cycles in 1M KOH. Data labels indicate cobalt concentration as at.% Co/(at.% Co+ at.% Ni). Figure 1

Inhomogeneous Degradation in Lithium-Ion Batteries: The Effect of Thermal Gradients

Understanding lithium ion battery degradation is a consequence of multiple, tightly coupled and non-linear degradation mechanisms. The interplay between these degradation mechanisms, and how the cell is used, gives rise to path dependent behaviour, and hence data driven approaches to model behaviour and predict lifetime rapidly become prohibitively expensive. Therefore, a physics based approach to model degradation is desirable.In addition, all of the degradation mechanisms are a function of temperature, which adds another variable to the path dependency. To make matters worse, all cells experience internal thermal gradients during operation, which means the path dependency for different regions within a battery will be different. This leads to inhomogeneous degradation. After a few cycles, the degradation pathway of each region will then be affected not just by the thermal gradients and local current density but also by the state-of-health of that region, leading to complicated emergent behaviour.Solving a physics based model with multiple degradation mechanisms, in a detailed 3-dimensional thermally coupled discretised model is also prohibitively expensive. Therefore, in this paper we present a thermally coupled distributed equivalent circuit model, with degradation functions built in, so each node can degrade at different rates, as a function of the operating conditions at that node. We have reproduced experimental data previously published, showing the effect of thermal gradients on degradation for two different cooling strategies for a tab and surface cooled pouch cell. For the first time reproducing the positive feedback mechanism responsible for accelerated degradation for surface cooling.The results of this work show that thermal gradients cannot and should not be ignored, and degradation models that do not take them into account have a significant risk of overfitting and leading to incorrect conclusions.

Comparative Study on Transport Property of Asymmetric Fluorosulfonyl(trifluoromethylsulfonyl)Amide-Based Phosphonium Ionic Liquids

Room-temperature ionic liquids (RTILs), i.e. organic molten salts with melting points below ambient temperature, have been regarded as potential electrolytes for various electrochemical systems, because RTILs have unique physicochemical properties such as favorable solubility of organic and inorganic compounds, relatively high ionic conductivity, no measurable vapor pressure, high thermal stability, low flammability, etc. The quaternary phosphonium cation based RTILs have attracted attention in recent years due to their high chemical and thermal stabilities. We have proposed and synthesized a class of low viscous and highly conductive RTILs based on triethylalkylphosphonium cations in combination with typical sulfonylamide-based anions, e.g. bis(trifluoromethylsulfonyl)amide (N(SO2CF3)2 -, TFSA) and bis(fluorosulfonyl)amide (N(SO2F)2 -, FSA) anions.1,2 Our recent approaches include a design and synthesis of low-melting phosphonium based RTILs together with asymmetric fluorosulfonyl(trifluoromethylsulfonyl)amide (N(SO2F)(SO2CF3)-, FTA) anion. In this work, we report the transport property and unique viscosity behavior of several FTA anion based phosphonium RTILs as shown Fig. 1. The FTA-based phosphonium RTILs was synthesized by aqueous ion exchange reaction of the precursor quaternary phosphonium halides with lithium FTA. The crude RTILs obtained were hydrophobic and purified by washing with pure water several times in order to remove residual metal and halide ions. The RTILs thus prepared were dried under high vacuum for at least 1 day. The physicochemical properties of RTILs, e.g. density, viscosity, conductivity (ac impedance method), were measured at elevated temperatures under argon atmosphere.Several low-melting phosphonium RTILs were successfully prepared by combination with FTA anion (P2225, P2228 and P4441-FTA). All FTA-based phosphonium RTILs showed typical temperature dependent behaviors for density, viscosity and electrical conductivity. The conductivities of FTA-based phosphonium RTILs were higher and lower than those of corresponding TFSA- and FSA-based phosphonium RTILs, respectively; however, it should be noted that the viscosities of FTA-based phosphonium RTILs were the lowest in the phosphonium RTILs as depicted in Fig. 2. To our knowledge, such a unique viscosity behavior has not been previously reported in the FTA-based ammonium based RTILs. The detailed transport property and electrolytic behaviors such as the Arrhenius plots of viscosity and conductivity with VTF fitting and the Walden plots will be also discussed in comparison with both corresponding TFSA- and FSA-based RTILs.References1) K. Tsunashima, et al, Electrochem. Commun., 9, 2353 (2007).2) K. Tsunashima, et al, Electrochem. Commun., 13, 178 (2011). Figure 1

Fabrication of Two-Dimensional Homo-Bimetallic Porphyrin Framework Thin Films for Optimizing Nonlinear Optical Limiting.

Developing efficient metal-organic framework (MOF) optical devices with tunable third-order nonlinear optical (NLO) properties is an important challenge for scientific research and practical application. Herein, 2D monometallic and hetero/homo-bimetallic porphyrin MOF thin films (ZnTCPP(M) M = H2, Fe, Zn) were fabricated using the liquid-phase epitaxial (LPE) layer-by-layer (LBL) method to investigate the metal substitution dependent third-order NLO behavior. The prepared homo-bimetallic ZnTCPP(Zn) thin film exhibited enhanced third-order NLO performance with a higher third-order nonlinear susceptibility of ∼4.21 × 10-7 esu compared to monometallic and hetero-bimetallic counterparts. Additionally, theoretical calculations were performed to complement the experimental findings and revealed that the enhanced NLO effect of the ZnTCPP(Zn) thin film is mainly attributed to the enhanced local excitation. These findings not only provide a comprehensive understanding of the relationship between metal types and the NLO behavior of porphyrin MOF thin films but also offer valuable insights into the design and optimization of NLO devices.

Synthesis and characterization of (1-x)Bi0.9Sm0.1FeO3 - (x)BaZr0.15Ti0.85O3 based solid solution: Temperature-dependent dielectric and impedance properties

Lead-free solid solution of (1-x) Bi0.9Sm0.1FeO3 − (x) BaZr0.15Ti0.85O3 (BSFO − BZT) (x = 0.0, 0.10, 0.15, 0.20, 0.25, 0.50) ceramics were prepared using solid-state reaction method. The structural, morphological, temperature-dependent dielectric properties and leakage current were investigated. The structural investigation revealed the formation of perovskite structure coexisting with tetragonal and rhombohedral phases within (BSFO–BZT) ceramics. The dielectric measurements (within 303 K-773 K) confirmed the existence of a morphotropic phase boundary at x = 0.15 for the (BSFO–BZT) system. The frequency and temperature dependent electrical behavior were explained using Ac conductivity and impedance analysis. The leakage current behavior for all these samples was investigated using both space charge-limited conduction (SCLC) for bulk and Schottky emission (SE) for limited interface conduction approach, whereas the pure BSFO sample was found to be dominated by ohmic conduction, while the BZT-doped samples were dominated by grain boundary-limited conduction.The sample (0.80)Bi0.9Sm0.1FeO3-(0.15)BaZr0.15Ti0.85O3 achieved largest dielectric constant 330 at 10 KHz along with a moderate leakage current density value of 3.54 × 10-5A/cm2 (which is quite lower than pure BSFO) proven its candidacy to develop a stable photovoltaic, multilayer actuators, and ferroelectric memory devices.

THE RELATIONSHIP BETWEEN DYSMENORRHEA KNOWLEDGE AND DYSMENORRHEA HANDLING BEHAVIOR IN YOUNG WOMEN AT SMAN 1 TAMBUN UTARA IN 2022

Many young women ignore pain during menstruation. Dysmenorrhea has a bad impact on young women, namely causing disturbances in teaching and learning activities, not paying attention to the explanations given by the teacher, and the tendency to sleep in class during teaching and learning activities. Health conditions during menstruation are influenced by the level of knowledge. A person with insufficient knowledge will tend to ignore health and in the end, he will have dangerous actions for himself. research Objectives:To determine the relationship between knowledge about dysmenorrhea and behavior in handling dysmenorrhea in adolescent girls at SMAN 1 Tambun Utara in 2022. Research Methods: The design in this study was Analytical Observation with a Cross-Sectional research design, using the independent variable knowledge of dysmenorrhea and the dependent variable handling behavior, the sampling technique in this study is probability sampling type simple random sampling with a sample of 205 respondents. The instrument in this study used a digital questionnaire and statistical tests were carried out using Chi-Square. Research Results: Based on the output of the chi-square statistical test, the Asymp Significance value is 0.000. It can be concluded that the Asymp Significance value (0.000) &lt; value (0.05), indicates that H0 is rejected. Thus it can be interpreted that "the relationship of knowledge about dysmenorrhea with behavior in handling dysmenorrhea in adolescent girls at SMAN 1 Tambun Utara in 2022. Conclusion: There is a relationship between knowledge about dysmenorrhea and behavior in dealing with dysmenorrhea in adolescent girls at SMAN 1 Tambun Utara in 2022.

Influence of high frequency on the fatigue life of metallic single lap joints

Polymer adhesives are known to exhibit time dependent mechanical behaviour, that becomes more and more evident approaching the glass transition temperature, Tg. When subjected to fatigue, bonded joint lifetime can be therefore affected by the loading frequency and amplitude. According to the literature, the influence of the frequency on the fatigue behavior manifests as a rise of the temperature in the adhesive due to the hysteretic heating, which is related in turn to Tg and to the viscoelastic properties of the adhesive. In this paper, cyclic loading was applied to single lap shear joints until failure at frequencies in the range of 70–90 Hz, that are little explored by the existing literature. The aim is twofold: on one side, to investigate the possibility to speed up fatigue tests in comparison to tests performed in the range of 7–9 Hz; on the other side, to explore the possibility to generate stress-life data in a range of number of cycles between 106 and 108, therefore two order of magnitude higher then usual, without exceeding with the time required for the tests. The joints were made with both aluminum and stainless-steel substrates bonded with a structural epoxy adhesive, to manufacture a Single Lap Joint (SLJ). Two loading ratios R (respectively 0.1 and 0.4, defined as the minimum over the maximum force of the fatigue cycle) and different load ranges were applied. Digital Image Correlation (DIC) technique was used to assess the presence of creep strains. A preliminary investigation consisting in a Dynamic Mechanical Analysis (DMA) of bulk adhesive for the range of frequency of interest, and in the measurement of the temperature of the adhesive layer during some selected fatigue tests was carried out. No significant changes of the viscoelastic properties of the adhesive were found for the frequency of interest, and, at the same time, temperature measurements revealed that the temperature increased by a few degrees, remaining in any case far from the glass transition temperature. The test results showed that only small effect due to the application of a high frequency cyclic loading on the fatigue life apparently occurs for tests carried out at the lowest load ratio, in particular when the applied loads were relatively low, and the number of cycles at failure relatively high. On the opposite, the results of tests carried out at the highest load ratio are affected by the loading frequency, and it has been related to the presence of significant creep deformation within the adhesive layer.

Contact time dependence of adhesion force studied at low, moderate, and high relative humidities on AFM: Influence of surface hydrophilicity

Contact time dependence of adhesion force remains insufficiently comprehended and demands further clarification. Adhesion forces between cantilevers and various substrates were measured with atomic force microscopy to study the dependence at low, moderate, and high relative humidities (RH). Results indicate a strong correlation between the dependence and surface hydrophilicity. In some situations, the adhesion force exhibits a dependence on contact time: it experiences a rapid increase, followed by a gradual rise and eventual saturation with a saturation time of 20 ∼ 200 s. On hydrophilic surfaces, the force is dependent only at some RHs. On most partially hydrophobic surfaces, the dependent behaviors are observed under all levels of RH. However, the force on hydrophobic surfaces is independent under all levels of RH. With the dominant capillary force, the dependent behavior was attributed to the slow flow of thin films caused by the high viscosity of interfacial water. The high viscosity at low and moderate RHs was due to its configuration and film thickness, while that at high RH was due to contaminants and the formation of silica sols and gels. The findings have the potential to enrich the comprehension of adhesion and provide remedies for stiction-related problems in miniature devices.

Spatially modulated interface states in a two-dimensional potential: Single-layer RbI on Ag(111)

Alkali halides are known to exhibit interface electronic states (IES) when deposited on metal surfaces with ultra-thin coverage. Here, we examine the IES formed by sub-monolayer RbI growth on Ag(111), which exhibits spatial variations in electronic structure in surprising contrast to the results previously obtained for other alkali halides. We find that this spatially dependent behavior can be qualitatively modeled by using a two-dimensional cosine potential commensurate with the moiré superstructure, where the IES is constructed from the well-known analytical solutions to the Mathieu equation. Our results indicate this potential is more corrugated than for similar potentials reported for other alkali halides, a result of substrate–adlayer charge transfer interactions that are stronger for RbI. This two-dimensional effective potential leads to anisotropy in the effective electron mass, in surprising contrast to previous results for other alkali halides, which report a single isotropic mass.

Coupled effects of corrugation and rotation on the phase transition and thermal process in a vented cavity under MHD convection

One of the challenges in the utilization of phase change materials (PCMs) is their low thermal conductivity. Therefore, for effective usage of PCMs in thermal systems, novel methods for phase change process control such as geometry modification and incorporating different boundary conditions can be adopted. In this study, phase transition and thermal process in a triangular shaped wavy enclosure equipped with spherical shaped encapsulated PCM are explored under magneto-convection of nanofluid. The inner walls of region where PCM is embedded is rotating and sinusoidal form of corrugation is considered for the wavy wall of the triangular cavity. Numerical calculations are done for different values of Re (200≤Re≤1000), Rew (−2500≤Rew≤2500), Ha (0≤Ha≤60), wave amplitude (0≤Ap≤0.1H) and wave frequency (2≤Np≤8). It is observed that when rotations are active at Rew=100, phase transition time (TF) is reduced by 12.5% while it is increased by 16.6% at Rew=0. Magnetic field is effective when used without rotation of the inner part. The amount of reduction of TF with magnetic field at the highest strength is obtained as 15.8%. The heat transfer is reduced with higher Ha for stationary and rotating cases while reduction amount up to 14% can be achieved. Amplitude of the wavy form of cavity wall is influential on the phase change process at Rew=0 and TF is reduced by about 14.5%. The contribution of amplitude and frequency of the wave form on the heat transfer is very slight. Optimum parameter set for lowest TF is obtained at (Re, Rew, Ha, Ap, Np) = (600, 2500, 60, 0.075H, 2) while for highest heat transfer rate it becomes (Re, Rew, Ha, Ap, Np) = (1000, 2500, 0, 0.1H, 8). Generalized neural network based modeling is found to be an efficient way of predicting the time dependent behavior of phase change process with respect to changes in operating parameters such as Re, Rew and Ha.

Viscoelastic constitutive artificial neural networks (vCANNs) – A framework for data-driven anisotropic nonlinear finite viscoelasticity

The constitutive behavior of polymeric materials is often modeled by finite linear viscoelastic (FLV) or quasi-linear viscoelastic (QLV) models. These popular models are simplifications that typically cannot accurately capture the nonlinear viscoelastic behavior of materials. For example, the success of attempts to capture strain (rate)-dependent behavior has been limited so far. To overcome this problem, we introduce viscoelastic Constitutive Artificial Neural Networks (vCANNs), a novel physics-informed machine learning framework for anisotropic nonlinear viscoelasticity at finite strains. vCANNs rely on the concept of generalized Maxwell models enhanced with nonlinear strain (rate)-dependent properties represented by neural networks. The flexibility of vCANNs enables them to automatically identify accurate and sparse constitutive models of a broad range of materials. To test vCANNs, we trained them on stress-strain data from Polyvinyl Butyral, the electro-active polymers VHB 4910 and 4905, and a biological tissue, the rectus abdominis muscle. Different loading conditions were considered, including relaxation tests, cyclic tension-compression tests, and blast loads. We demonstrate that vCANNs can learn to capture the behavior of all these materials accurately and computationally efficiently without human guidance. Our source code is available at https://github.com/ConstitutiveANN/vCANN.

Container Closure Integrity of a Glass Prefillable Syringe in Deep Frozen Storage Conditions

Development of novel pharmaceutical drug modalities has created a need for frozen storage and transportation. Accurate and easy assessment of container closure integrity (CCI) in frozen conditions remains a challenge. Thus, container closure systems (CCS) suitable for low temperatures have been primarily restricted to vials despite the growing popularity of prefillable syringes (PFS) for parenteral administration. A new dye ingress test method, suitable for testing at low temperatures, was developed and applied to PFS across a range of deep-frozen temperatures. The method is versatile and can easily be extended to other common CCS formats over a wide range of temperatures including storage on dry ice (-80 °C). This new method was paired with an orthogonal technique, laser-based CO2 headspace gas analysis, to evaluate the CCI of a glass PFS at temperatures from -50 °C to -80 °C. Both test methods showed comparable results and consistent CCI failure below a temperature of -70 °C. The primary mode of failure was the plunger-to-barrel interface, likely attributable to dimensional changes and loss of elasticity. This study demonstrates the temperature dependent CCI behavior of glass PFS and underscores the importance of thorough characterization of package integrity for deep frozen drug products.

Green Synthesis of Silver Nanoparticles: Their Optical and Rheological Properties

The goal of this work was to investigate the green synthesis of silver nanoparticles (Ag NPs) from aqueous Propolis (P) extract, and their optical and rheological properties. Using scanning electron microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS) and X-ray diffraction (XRD) studies nanostructure of the prepared Ag NPs were characterized. Further, the aforementioned study suggests that Ag NPs with an average size of around 23 nm have a well-developed polycrystalline cubic structure. In the UV-Vis absorption spectra, the surface plasmon resonance (SPR) peak showed maximum absorption at 418 nm. For an excitation energy corresponding to the wavelength 410 nm, photoluminescence (PL) spectra of Ag NPs exhibited emission peak at 495 nm. To explore temperature (T) dependent flow behaviour of biosynthesized colloidal Ag NPs dispersion in deionized (DI) water, flow curve studies under shear for T= 20, 30 and 40 °C were done using rheometer. The above study illustrated that the colloidal Ag NPs follows shear thickening non-Newtonian behaviour. Moreover, viscosity decreased as temperature increased, indicating that the silver nanofluids can exhibit more rational thermal performance under high temperature conditions.

A highly efficient, rapid, room temperature synthesis method for coal-based water-soluble fluorescent carbon dots and its use in Fe3+ ion detection

We report a method for the of coal-based fluorescent carbon dots (CDs) at room temperature using a mixture of hydrogen peroxide (H2O2) and formic acid (HCOOH) as the oxidant instead of concentrated HNO3 or H2SO4. The CDs have an excitation dependent behavior with a high quantum yield (QY) of approximately 7.2%. The CDs are water soluble and have excellent photo-stability, good resistance to salt solutions, and are insensitive to pH in a range of 2.0-12.0. The CDs were used as a very sensitive probe for the turn-off sensing of Fe3+ ion with a detection limit as low as 600 nmol/L and a detection range from 2 to 100 μmol/L. This work provides a way for the high value-added utilization of coal.

Torque dependent behavior of the vehicle background noise and its influence on masking thresholds in electric vehicles

The quality and comfort perception in vehicles is strongly influenced by the overall sound quality of the vehicle. Besides aerodynamic and tire noise, tonal powertrain noise plays an important role and can have a strong negative impact on sound quality. An assessment of the perceptibility of tonal noise with respect to masking noise is therefore essential for the vehicle development process. Due to the absence of masking by the internal combustion engine in electric vehicles and the wider frequency range of the powertrain noise, new methods are required for this purpose. In order to evaluate state of the art masking models and a newly developed method regarding the audibility of tonal components, masking thresholds for tonal noise in the vehicle interior are experimentally determined in listening tests. A currently developed extension of the method will also allow roller dynamometer measurements to be used for the evaluation. Currently, the masking signals are mostly generated with torqueless coast down measurements to consider the worst-case scenario. However, a torque dependency has to be taken into consideration. In this paper the torque dependency of the masking noise and the resulting influence on masking threshold is shown for road and roller dynamometer measurements.