Full Contact Research Articles

Rhombohedral stacking-faults in exfoliated highly oriented pyrolytic graphite

The recent observation of possible granular superconductivity in highly oriented pyrolytic graphite (HOPG) has attracted significant research interest. Here we report a novel investigation on the structural-properties of exfoliated-HOPG. We investigated two types of exfoliation methods, involving either a full (method-1) or partial (method-2) contact between adhesive tape and the main HOPG. Structural characterization was obtained by employing X-ray diffraction (XRD), Raman spectroscopy and electron microscopy (SEM). In particular, Raman point and mapping spectroscopy revealed significant structural-transitions from ABA (Bernal) to ABC (rhombohedral) stacking (stacking-faults), in those samples obtained with the method-2. Interestingly, strained regions exhibiting structural-deformations with a ridge-like morphology were reproducibly identified. The acquired Raman-spectra revealed a local enhancement of the D and D’ bands-intensity together with contributions arising from Electronic Raman Scattering (ERS) across the band-gap of rhombohedral-graphite, at middle (∼1870 cm−1) and high (∼ 2680 cm−1) frequency. HRTEM of the samples produced with the method-2 allowed also for the identification of local-coexistence of ripplocation-like defects with moiré superlattices, an indicator of non-uniform c-axis configuration.

Hierarchical core-shell structured CoZn-MOFs derived materials anode with raspberry-like shape for high-performance lithium storage

Significant progress had been made in various fields with transition metal oxide electrode materials, particularly in battery materials where structural control played a crucial role in enhancing their electrochemical properties. Therefore, this study aimed to investigate the potential of a raspberry-like hierarchical core-shell structure derived from Co–Zn MOF as anode materials by varying concentration of reaction solution in hydrothermal method. The hierarchical raspberry-like hollow shell structure was beneficial to expose more active sites and reduced the diffusion distance of Li+ to the internal electroactive sites, improving the overall electrical conductivity of the electrode by full contact with carbon. Carbon nanotubes were incorporated into more suitable core-shell structure. They were uniformly coated the hollow sphere and filled inside of that to form a carbon skeleton. Specifically, the carbon nanotubes inside of the hollow sphere supported the shell not to collapse. This mitigated volume expansion during the cycling process, maintains structure stability, and allowed for rearrangement to occur during cycling to achieve a high specific capacity. Furthermore, the carbon nanotubes inside and outside of the hollow sphere created a high-density interface that enhanced interfacial polarisation and accelerated the rate of Li+ passage during cycling. These effects had resulted in an improvement in the material's performance. It is noteworthy that the specific capacity attains 1050 mAh g-1 when exposed to a current density of 0.2 A g-1. Notably, even after conducting 500 cycles at a current density of 0.5 A g-1, the specific capacity remains stable at 652 mAh g-1.

Temperature-switchable deep eutectic solvent extraction of polysaccharides from wolfberry fruits: Process optimization, structure characterization, and antioxidant activity

Polysaccharides of wolfberry (LBPs) with complex structures are most commonly used in the food and pharmaceutical industries as biologically active phytochemicals. However, the structure and yield of LBPs vary according to the extraction method used, and selecting their extraction media remains difficult. A novel type of temperature-switchable deep eutectic solvent (TS-DES), consisting of L-menthol and phenyl salicylate, was designed to extract LBPs from wolfberry fruits. TS-DES was a recyclable extractant above the maximum critical solution temperature (UCST). The increased dispersibility of extraction solvents was imparted by combining them with a high-speed shear dispersion emulsification (HSDE) machine. TS-DES was in full contact with the cell walls of wolfberries, leading to the complete opening of the cell walls, resulting in the efficient extraction of LBPs. Compared with traditional extraction, the yield of LBPs-D reached 4.35%, which was higher than that of LBPs-W (1.78%). This study showed that LBPs-D were high molecular weight, highly branched polysaccharides with antioxidant activity. TS-DES was separated at a lower level than UCST for regeneration and reuse. After 5 cycles, TS-DES still had excellent recovery and extraction performance. This study provides valuable information for efficiently extracting structurally rich bioactive polysaccharides from plants using TS-DES.

Influence of the Advance Jacked Pipe on the Jacking Force of the Subsequent Pipe Based on Pipe–Soil Full Contact Model

Abstract In pipe jacking engineering, accurate prediction of jacking force is the key to pipe jacking design. Based on a project of the Beijing Daxing Airport Line, the influence of the advance jacked pipes on the jacking force of the subsequent pipe is carried out in the present work. First, the verified numerical model of practical engineering was established, and the jacking force and radial stress of different pipes were analyzed. Then, the two pipes were taken as research object, and the parameters of spacing, angle, buried depth, and pipe diameter were investigated, respectively. The results show that in the actual project, the advance jacked pipes have amplification and superposition effects on friction resistance of the subsequent pipe, and the maximum growth rate is 37.2%. The friction resistance of the subsequent pipe presents a trend of first increasing and then decreasing with the change of the layout angle of advance jacked pipe from 0° to 180°. With the increase of buried depth and pipe diameter, the absolute value of incremental friction resistance of the subsequent pipe increases gradually, but the growth rate remains constant. Finally, the empirical formulas for predicting the friction resistance growth rate of subsequent pipes under different angles are proposed. The research results can provide some reference for the design of pipe jacking.

The Electrical Contact Solution for Measuring Back Contact Solar Cells

Due to the cell design, it is challenging to measure back contact cells. In this study, we have designed and tested a contact chuck based on printed circuit board (PCB) technology. Both full cells and cut Interdigitated Back Contact (IBC) cells were tested and compared to a conventional spring-loaded probes based measurement chuck. Results show that IV parameters, especially fill factor (FF), can be measured with high accuracy and repeatability. In this case, the FF results are closer to the FF of modules. The chuck can also be used for other measurements, for example, electroluminescence and spectral response. The PCB layout can be adjusted according to the cell design, providing a more flexible, faster, and cost-effective approach than the traditional measurement chuck. The technology is suitable for measuring back contact cells in lab environments and in industry.

Application study of pyrolysis and steam gasification of modified fly ash mixed with coal

Coal fly ash (CF) is used in coal pyrolysis or gasification as a result of the high content of oxide metals. However, CaSO4 and SiO2 in CF inhibited catalytic activity. Herein, the application of acid-base modified CF to steam gasification of coal (CA). It was found that the order of acid-alkali modification had different effects on the H2 production. NaOH–HF (A-E) modified CF, there was no CaSO4 present on the surface of CF, and the surface SiO2 shell structure was destroyed, releasing more α-Fe and α-Fe2O3. A new Fe active phase (FexFy) had been formed. Meanwhile, the functional groups on the surface of modified CF changed, resulting in more C–H bonds, which provided more H sources for gasification. The α-Fe and α-Fe2O3 in NaOH–HF modified CF were in full contact with coal and steam, breaking the O–H bonds in the H2O, the aliphatic side-chain hydrocarbons and C–H bonds in the coal to produce more H2. α-Fe2O3 and α-Fe undergoes mutual transformation at the action of H2, providing more Fe to increasing H2 production. When the gasification temperature was 900 °C, the steam flow rate was 1 mL/min and the heating rate was 10 °C/min, the H2 yield increased from 915.97 mL/g-(E-A) to 1539.72 mL/g-(A-E), the carbon conversion of coal gasification was 99.68%.

Dual material fused filament fabrication of composite core‐shell structures with improved impact resistance and interfacial adhesion

AbstractThe mechanical performance of parts produced by fused filament fabrication (FFF) has been limited due to the presence of voids and poor interlayer welding. Recent advancements in FFF have enabled the fabrication of void‐free objects with strong interlayer welding through the use of semicrystalline polymer shells such as high‐density polyethylene (HDPE) along with a high viscosity core polymer like acrylonitrile‐butadiene‐styrene (ABS). The zero‐shear viscosity (η0) of ABS is three orders of magnitude higher than HDPE making the ABS‐HDPE core‐shell configuration preferable. ABS holds the shape by preventing bulk flow and part bending while HDPE promotes full surface contact across the layers. Most polymers, however, are immiscible which causes a weak weld line along the core‐shell interface. Herein, maleic anhydride (MAH) is grafted to the butadiene segment of the ABS core thereby compatibilizing the interface with HDPE, improving the interfacial adhesion. Attenuated total reflectance‐Fourier transform infrared spectroscopy was employed to confirm successful grafting. Using a custom‐made die affording the core‐shell structure, the ABS‐g‐MAH is shown to improve the impact resistance by 253% and 16% compared to neat HDPE and ABS specimens, respectively. Additionally, a 10% increase compared to the unmodified ABS‐HDPE core‐shell configuration is observed.

One-Step Photochemical Preparation of CdS/Poly(MMA-co-MAA) Composite with Enhanced Photocatalytic Activity.

This paper presents a one-step photochemical method for the preparation of CdS/Poly(MMA-co-MAA) composite photocatalyst, based on the concept of simultaneous photocatalytic polymerization of organic monomers during UV-light induced formation of CdS. The preparation is carried out in an aqueous solution of Na2S2O3, CdSO4, methyl methacrylate (MMA) and methacrylic acid (MAA), under a UV lamp. The continuously formed CdS particles with photocatalytic activity act the role of initiator to directly initiate the copolymerization of MMA and MAA, resulting in the in situ formation of the composite and full contact of the CdS particles with the oxygen-containing groups in the polymer. Taking the photocatalytic degradation of methylene blue as a case study, the composite exhibited significantly higher activity under simulated solar light compared to the pure CdS. By analysis on various data, the enhanced photocatalytic activity is attributed to the enhanced visible light absorption, and especially the high electron-hole separation efficiency caused by the electrostatic interaction between photogenerated holes and carbonyl oxygen atoms with negatively charged features. Furthermore, the composite displays excellent sunlight activity and recyclability, suggesting its potential for practical applications. Such a one-step construction strategy relying only on photo-energy is green, low-cost and promising in obtaining high-performance semiconductor/polymer composite photocatalysts.

Influence of Environmental Conditions on the Electrical Parameters of Side Connectors in Glass–Glass Photovoltaic Modules

This work focused on the verification of the electrical parameters and the durability of side connectors installed in glass–glass photovoltaic modules. Ensuring the safe use of photovoltaic modules is achieved, among others, by using electrical connectors connecting the PV cell circuit inside the laminate with an external electric cable. In most of the cases for standard PV modules, the electrical connector in the form of a junction box is attached from the back side of the PV module. The junction box is glued to the module surface with silicone where the busbars were previously brought out of the laminate through specially prepared holes. An alternative method is to place connectors on the edge of the module, laminating part of it. In such a case, the specially prepared “wings” of the connector are tightly and permanently connected using laminating foil, between two glass panes protecting against an electrical breakdown. Additionally, this approach eliminates the process of preparing holes on the back side of the module, which is especially complicated and time-consuming in the case of glass–glass modules. Moreover, side connectors are desirable in BIPV applications because they allow for a more flexible design of installations on façades and walls of buildings. A series of samples were prepared in the form of PV G-G modules with side connectors, which were then subjected to testing the connectors for the influence of environmental conditions. All samples were characterized before and after the effect of environmental conditions according to PN-EN-61215-2 standards. Insulation resistance tests were performed in dry and wet conditions, ensuring full contact of the tested sample with water. For all modules, before being placed in the climatic chamber, the resistance values were far above the minimum value required by the standards, allowing the module to be safely used. For the dry tests, the resistance values were in the range of GΩ, while for the wet tests, the obtained values were in the range of MΩ. In further work, the modules were subjected to environmental influences in accordance with MQT-11, MQT-12, and MQT-13 and then subjected to electrical measurements again. A simulation of the impact of changing climatic conditions on the module test showed that the insulation resistance value is reduced by an order of magnitude for both the dry and wet tests. Additionally, one can observe visual changes where the lamination foil is in contact with the connector. The measurements carried out in this work show the potential of side connectors and their advantage over rear junction boxes, but also the technological challenges that need to be overcome.

A study on the classification of geological background source cadmium migration phases in Zhejiang Province, China

The release of cadmium during the natural weathering process of cadmium-containing strata is a significant source of cadmium pollution in both water and soil. The Hetang formations, wildly located in Jiangxi Province Zhejiang Province and Anhui Province in China, is a typical example of a cadmium-rich black shale stratum and is one of the primary sources of soil cadmium contamination. The bottom coal seam of this formation has been found to contain high levels of cadmium, with concentrations up to 11.26 mg/kg. As a result of water flow eroding the riverbed, parent rocks containing cadmium undergo continuous weathering, releasing cadmium elements. This process contributes to cadmium pollution in downstream soil, originating from the geological background. By utilizing techniques such as FE-SEM, EDS, and optical microscopy, this study investigates the distribution of iron in rock fragments with varying degrees of weathering in the riverbed. The research aims to examine the influence of iron distribution on the migration of cadmium originating from geological background sources. Based on the co-occurrence and co-migration characteristics of iron and cadmium in the study area, this research aims to reveal the migration features of geological background source cadmium by exploring the distribution patterns of iron sediment within rock fragments. By comparing sediment samples from both upstream and downstream river channels, we were able to identify three distinct stages that indicate the presence of cadmium originating from geological sources under weathering conditions: the unweathered stage; the intra-detritus migration stage, and the completely weathered stage; intra-detritus migration stage; and completely weathered stage. Furthermore, after leaving the Hetang formations shale outcrop area, there was a sharp decrease in content for Hetang formations detritus. At this point geological background source cadmium had largely escaped from constraints imposed by rock microstructure and had come into full contact with water. The findings from this research deepen our understanding regarding migration patterns for geological background source cadmium. They also reveal formation processes for geological background source cadmium pollution and provide a theoretical basis for identification and treatment for geological background source cadmium pollution.

Comparative Study on Tibialis Posterior Muscle Strengthening Exercise Vs Quadriceps Muscle Strengthening Exercise in Reducing Pain and Improving the Functional Status for Peoples with Anterior Knee Pain

Background: Flat foot is a condition in which the Medial longitudinal arch (MLA) has a more flattened curve whenfoot makes full contact with the ground. In medical terms, flat foot is associated with the pronated foot. For peopleages 20 to 60, flat foot prevalence is 13.6%. People who have weak posterior tibial tendons are more likely to haveflat feet and Flat foot is one of the contributing factors to development of anterior knee pain.Purpose: To compare the effectiveness of Tibialis posterior strengthening exercise and Quadriceps strengtheningexercise among people with anterior knee pain.Materials and Method: The experimental study included 170 volunteers, both male and female, aged 20-60years, who were drawn from Martin Physiotherapy Clinic by convenience sample method. informed consentwas obtained before beginning the study. The participants were divided into two groups, the Tibialis posterior(n=85) group received Tibialis posterior strengthening exercise, whereas the Quadriceps (n=85) group receivedQuadriceps strengthening exercise. The intervention was administered five times over the course of six weeks.Study Period: March 2023 to July 2023.Results: The collected data was statistically analysed using paired and unpaired t-test, showed significantimprovement in Tibialis posterior group than quadriceps group with p<0.0001.Conclusion: The study concludes that Tibialis posterior strengthening was more effective in reducing pain andimproving functional status among peoples with anterior knee pain.

Mediating role of self-reflection and insight in the relationship between forgiveness and Gestalt contact disturbances

During the university period, individuals join a social environment in which they learn to establish new relationships. The emergence of these new experiences can bring about interpersonal conflicts and the process of forgiveness. Disturbances in the individual's interactions with oneself and others during this process may have negative effects on forgiveness. Some theories and models mention the important roles of self-reflection and insight into the forgiveness process. However, the relationships between Gestalt contact disturbances, forgiveness, self-reflection, and insight were not examined sufficiently. The aim of the current study is to examine the mediating roles of self-reflection and insight in the relationship between Gestalt contact disturbances (contact, full contact, dependent contact, post-contact) and forgiveness (self forgiveness and forgiveness of others) in a sample of university students. The participants were a total of 377 university students, 246 (65.3%) women and 131 (34.7%) men, who were reached by convenient and snowball sampling methods. The current study included university students aged 18-30, with an average participant age of 23.93. In the data collection process Gestalt Contact Disturbances Scale, Self-Reflection and Insight Scale and Forgiveness Scale were applied. Descriptive statistics, correlation and mediation analyses were conducted using SPSS 23.0 and PROCESS Macro 4.2 (Model-4). The findings indicated that insight had a mediating role in the relationship between contact and full contact with self-forgiveness. Self-reflection had a mediating role in the relationship between dependent contact and post-contact with self-forgiveness, while insight had a mediating role in the relationship between contact and forgiveness of others.

Friction Behavior of Fingers on Micro-Textured Flexible Surfaces

Abstract Compared to rigid materials, people have a distinct tactile perception when touching flexible materials. Moreover, adding micro-patterns to the surface enhances the tactile experience even further. This sensation arises from the physical stimulation of frictional behavior between the skin and flexible materials. Therefore, this study focuses on human fingers as the research subjects and employs flexible materials with micro-textured surfaces as frictional objects. A friction test setup is designed to conduct a series of finger friction experiments, and theoretical explanations are provided to elucidate the reasons for performance variations. Research findings show that as the normal load increases, the frictional force gradually increases while the friction coefficient decreases. The former is attributed to the expanding contact area, while the latter is due to the inconsistent rate of frictional force increment with the normal load. The impact of friction velocity is mainly caused by changes in the viscous forces generated at the liquid film in the contact interface and the energy loss in elastic hysteresis. On the other hand, the effect of surface micro-topography is primarily a result of the transition between partial contact and full contact modes under the influence of normal load, leading to alterations in the contact area. Overall, during the finger friction process on a flexible micro-textured surface, changes in contact area play a vital role in modifying frictional performance, with adhesive friction exerting a more significant influence than deformation friction. This study summarizes the variations in frictional performance parameters based on experiments and analyzes the effects of contact area changes and deformation friction mechanisms from a theoretical perspective, providing a theoretical foundation for exploring the genesis of delicate tactile sensations during friction.

Internet Service Provider User Customer Lifetime Segmentation Analysis using RFM and K-Means Algorithm

The characteristics of each customer can be segmented using RFM (Recency, Frequency, Monetary) which means customer's last transaction time, number of customer transactions, and amount of money spent. The Lifetime and K-Means methods are used to perform the process of clustering or grouping customers based on segmentation through RFM. The results will be divided into 4 clusters namely Gold, Silver, Platinum and Diamond. The results of clustering are visualized with graphs and cluster tables containing the results of segmentation and clusters or groups of From the results obtained from the previous stage, of the 104 customers in the Retail & Distribution Services (RDS) sector, 4 segments resulted in 43 customers with Platinum class, 39 customers with gold class, 14 customers with silver class, and 8 customers with platinum level. The most popular services services or product is high speed dedicated internet services, VPN IP package, and service network package as top 3 results. The largest amount of revenue services or product is transponder full time use services, support network and contact center application as top 3 results.

Comparative assessment of methods of the operative treatment of facial nerve damage caused during cerebellopontine angle neurinoma and meningioma removals

The aim of this research paper is to point out the preconditions for facial nerve damage during CPA tumour removals and, in such cases, the appropriate choice of reconstructive surgery. Materials and methods. In Uzhhorod National University, during the period of 2008 to 2019, surgical treatment of 212 patients with neurinomas and meningiomas of the CPA has been carried out. We have analyzed the cases of 35 (16.5%) patients with intraoperative damage of the facial nerve. The mentioned 35 patients underwent appropriate clinical examinations during the post-operative period, which confirmed the facial nerve damage to one degree or another according to the House-Brackmann scale. The clinical signs manifested as full eyelid contact with slight effort and slight facial asymmetry during maximal effortful laughter. Slight synkinesias were noticeable, and there were no contractures until the expression of clinical signs corresponding to grade 6 - total nerve paralysis in 5 patients. Results. The research demonstrated that patients with neurinomas larger than 3 cm in size are 5 times more likely to undergo intraoperative damage to the facial nerve than patients with the same tumour but 3 cm or less in size and 5 times more likely than patients with meningiomas as a whole. In the group of patients aged 20-40, there were twice as many men; in the group aged 40-50, women predominated; among patients older than 50, there were equal numbers of men and women. Remote catamnesis was traced in 19 patients, and contact with the rest of the patients was lost due to the war. Among the interviewed patients, 58% of the anastomosis was performed in the first 3 months after the initial surgery, 21% - in 4-6 months, and 21% - in more than 12 months. The optimal timing of reinnervation after the initial surgery is the first 6 months after tumour removal. Сonclusions. Nerve damage is more common during the removal of neurinomas 4cm or bigger in size. Reinnervation is accomplished by anastomosing the central end of the hypoglossal or accessory nerves to the peripheral end of the facial nerve, and both procedures are equally effective. Reinnervation should be performed 2 to 3 months after confirming nerve injury, but no later than 6 months.

Seimic performance of two rigid blocks coupled through a Maxwell visco-elastic device

The protection against seismic hazards for rigid block-like structures, commonly modeled as rigid blocks, is often achieved by coupling such structures with external protection devices. The most commonly used protection devices include dynamic mass absorbers, oscillating masses, base isolation systems, and hysteretic mass damper inerters. Additionally, several papers have studied the dynamic and seismic response of rigid blocks connected in series, with most of them focusing on the stacked rigid block system, where the blocks are placed one on top of the other. This paper investigates the seismic behavior of a system consisting of two rigid blocks connected in series through a linear visco-elastic Maxwell device. The aim is to understand the possibility of improving the seismic response of a rocking structure (modeled by one of the two rigid blocks) by connecting it with a rocking protection device (modeled by the additional rigid block). Each rigid block can exhibit three different types of motion: full contact, rocking motion around the left base vertex, and rocking motion around the right base vertex. Consequently, during the motion of the coupled system, nine different combinations can occur, each of which is described through a specific set of equations of motion. A parametric analysis is performed with the aim of investigating how the characteristics of the additional rigid block and connection device affect the seismic behavior of the main rigid block (the one modeling the rocking structure). The assessment is carried out through a comparison between the displacements of the coupled system and those of the stand-alone blocks. The results, organized in gain maps, show that there are several combinations of the characteristics of the additional rigid block and connection device that lead to an improvement in the seismic behavior of the main rigid block.

Structure Engineered High Piezo-Photoelectronic Performance for Boosted Sono-Photodynamic Therapy.

Sono-photodynamic therapy is hindered by the limited tissue penetration depth of the external light source and the quick recombination of electron-hole owing to the random movement of charge carriers. In this study, orthorhombic ZnSnO3 quantum dots (QDs) with piezo-photoelectronic effects are successfully encapsulated in hexagonal upconversion nanoparticles (UCNPs) using a one-pot thermal decomposition method to form an all-in-one watermelon-like structured sono-photosensitizer (ZnSnO3 @UCNPs). The excited near-infrared light has high penetration depth, and the watermelon-like structure allows for full contact between the UCNPs and ZnSnO3 QDs, achieving ultrahigh Förster resonance energy transfer efficiency of up to 80.30%. Upon ultrasonic and near-infrared laser co-activation, the high temperature and pressure generated lead to the deformation of the UCNPs, thereby driving the deformation of all ZnSnO3 QDs inside the UCNPs, forming many small internal electric fields similar to isotropic electric domains. This piezoelectric effect not only increases the internal electric field intensity of the entire material but also prevents random movement and rapid recombination of charge carriers, thereby achieving satisfactory piezocatalytic performance. By combining the photodynamic effect arising from the energy transfer from UCNPs to ZnSnO3 , synergistic efficacy is realized. This study proposes a novel strategy for designing highly efficient sono-photosensitizers through structural design.

Trends in Presentation and Management of Pediatric Renal Trauma

ObjectiveWe queried the Pediatric Health Information System (PHIS) to evaluate the presentation, management, and outcomes of renal trauma in children from birth to 18 years from 2007 to 2018. MethodsPatients were categorized as infants (0-1 year), toddlers (2-4 years), children (5-9 years), preteen (10-14 years), and teens (15-18 years) and patient demographics, grade of injury, and mechanism of injury including sports related trauma were collected. Each group was then evaluated for the level of management and patient outcome. ResultsWe identified 3720 patients with renal trauma. Our cohort was predominantly white (68.5%), male (68.6%), and required public insurance (38.5%). Most injuries were low grade (86.7%) and managed non-operatively (94.7%). The overall mortality was 51 (1.4%). Younger patients (infants, toddlers, children) were more likely to present with complex injuries and they were more likely to have been involved in a motor vehicle accident. They had higher blood transfusion rates, longer inpatient courses, higher levels of admission acuity, and higher mortality. Patients in the older age groups presented most after Sport Related Trauma (SRT). Across all age groups, the most common source of SRT was limited contact sports; however, when considering only teens, full contact sports were the primary offending activity. This review of the PHIS database provides insight to the rates and patterns of pediatric renal trauma in the United States. ConclusionOur data suggests an age-related differences in the presentation, management, and outcomes of pediatric renal trauma patients.

Ultra-thin nanohoneycomb porous CoMoO4 with excellent catalytic performance for water splitting at large current densities

Electrocatalytic water splitting for hydrogen production is considered the most effective and cleanest strategy to make full use of renewable energy. It still lacks the highly efficient and stable bifunctional catalyst to deliver high current density for large scale application of water splitting. Here, we innovatively developed a facile method to synthesize a three-dimensional (3D) honeycomb porous CoMoO4@pNi (porous nickel) catalyst with ultra-thin nanosheet, the generated oxygen vacancies and mesoporous structures with defects as active sites. We also precisely tuned the thickness and array structure to investigate its catalytic performance. The as-prepared CoMoO4@pNi catalyst delivers the overpotential of 377 mV for HER and 410 mV for OER, respectively, and only demands 1.99 V to reach a large current density of 1000 mA cm−2 for overall water splitting. CoMoO4@pNi catalyst is also operated for 200 h under 500 and 1000 mA cm−2, respectively, and both showed an ignorable current decrease. The excellent activity and stability are ascribed to the high surface area, short transport path for electrons and protons, the full contact between the exposed active sites and electrolyte, and the inherent stable nanohoneycomb porous structure of the ultra-thin nanosheet.

Applying effective feedback principles to promote the ethics of care and justice during emergency remote teaching and learning in three chemical engineering modules

The COVID-19 pandemic lockdown disrupted higher education practices and forced students and lecturers to rapidly migrate to emergency remote teaching and learning (ERT&L). Initially, ERT&L robustly focused on teaching and assessment to complete syllabi, without fully considering care and justice to students who were no longer consolidated in one location. During the lockdown, students were exposed to socio-economic plights, and mental health challenges, among others. Hence, this article aimed to consider how the pedagogical tool of effective feedback could promote the ethics of care and justice to support students during ERT&L. The feedback practices implemented during the lockdown were maintained after contact lectures resumed, and their effects were quantified to determine the overall impacts on optimizing T&L and ensuring a conducive learning environment- regardless of whether T&L occurs at university or remotely. Effective feedback practices, recommended by the literature, were applied by two lecturers within three undergraduate chemical engineering modules. Lecturer 1 adopted a blended learning approach in modules 1 and 2 before the lockdown, while lecturer 2 functioned as a full contact module. A quantitative research approach was adopted in which module and teaching evaluations were used to quantify the effects of the feedback interventions on T&L in the three modules. The results indicated an overall positive effect, with significant student satisfaction with the feedback interventions adopted from the literature to promote the ethics of care and justice during ERT&L. Based on the methodology and results, an empirical model is proposed to optimize any pedagogical intervention that education practitioners may strive to use to improve their assessment practices.