An electrochemical study of well-defined nafion coated platinum and platinum-bimetallic electrodes

In this investigation, cyclic voltammetry (CV), X-ray photoelectron spectroscopy (XPS) and rotating disc electrode (RDE) measurements of the oxygen reduction reaction (ORR) have been used to explore the complex three-phase Nafion-platinum-electrolyte interface. This interface is at the heart of the functioning membrane electrode assembly (MEA) of a fuel cell. CV was primarily used to analyse ultra-thin Nafion films, deposited (without contamination) onto various flat and stepped platinum and platinum bimetallic single crystal electrodes. For Pt{111}, XPS measurements were also used to determine Nafion surface layer thickness and to obtain surface chemical composition. CV results have shown that Nafion is a probe of adsorbed OH on platinum electrodes and for stepped surfaces, unusual structural sensitivity of Nafion-induced voltammetric peaks, ascribable to Nafion interactions with step sites, is observed as a function of average terrace width. Voltammetric results for palladium adlayers (up to two monolayers) adsorbed on Nafion coated Pt{111} and {100} in aqueous 0.1M HClO4, show the first layer palladium hydrogen underpotential deposition (HUPD) peak being much sharper and intense as compared to Nafion free surfaces. A similar phenomenon was found for platinum-palladium surface alloys in that Nafion adsorption would produce sharper, palladium HUPD peaks. This behaviour is ascribed to stronger specific adsorption of the Nafion sulphonate groups with palladium compared to platinum. It was interesting to note that for bismuth adlayers adsorbed onto Nafion coated Pt{111} and {100}, attenuation of HUPD features was identical whether or not Nafion was adsorbed but the Bi-OH redox features for Nafion coated surfaces exhibited marked differences, again ascribable to competitive adsorption of sulphonate and OH. Using RDE, it was found that the ORR for various Nafion coated Pt{hkl} electrodes was inhibited compared to Nafion free electrodes. The electrooxidation of formic acid on palladium modified, Nafion coated Pt{111}, in aqueous 0.1M HClO4, was found not to be affected by the presence of Nafion. However methanol electrooxidation was inhibited on palladium modified, Nafion coated Pt{111}. Finally a number of actual fuel cell electrocatalysts, provided by Johnson Matthey were characterised using CV. The {111} and {100} surface site densities were quantified using bismuth and germanium as surface probes. Comparisons between Nafion coated electrocatalysts and Nafion free electrocatalysts are also reported. It was found that only very marginal differences between the CV responses of both types of catalyst are recorded (in contrast to the single crystal data)

Corporate capital structure effects on corporate performance pursuing a strategy of innovation in manufacturing companies

Within the sphere of finance, the concept of capital structure has long been a subject of intense debate, serving as a quantitative depiction of the balance between debt, preference shares, and common stock within a company. This structure serves a crucial role in optimizing the utilization of a company's existing resources while simultaneously elevating the revenue streams for stakeholders. This particular study delves into the intricate relationship between corporate performance and capital structure, focusing on 78 publicly listed firms within the Dhaka Stock Exchange (DSE). Bangladesh holds the 29th position globally in terms of purchasing power, lending significant weight to this investigation. To comprehensively analyze this correlation, panel data encompassing the span from 2017 to 2021 was collected for these 78 sample companies operating within the DSE. Several key determinants of capital structure were considered in this analysis, namely the debt-to-equity ratio, short-term leverage ratio, long-term leverage ratio, and total debt ratio. Meanwhile, the performance of these firms was gauged using key metrics such as Return on Assets (ROA), Return on Equity (ROE), and Earnings Per Share (EPS). To ensure a robust analysis, factors such as inflation, liquidity, growth rate, tax rate, and firm size were meticulously controlled for. The findings unveiled a compelling narrative: all forms of debt ratios—be it short-term, long-term, or the total debt ratio—exhibited a substantial negative impact on ROA at a significant level of 1 %. Conversely, specific debt ratios, like the short-term total debt and the total debt-to-total asset ratio, displayed a notable positive correlation with ROE at a 1 % significance level. Intriguingly, the long-term total debt ratio yielded a negative and insignificant effect on ROE. Moreover, within the spectrum of predictors influencing a firm's performance, the liquidity ratio emerged as a non-significant factor—a notable discovery that highlights the nuanced nature of the interplay between capital structure and performance within these companies.</p

Texture depth prediction using distress deterioration curves

Road Surface Texture Depth (STD) is a critical aspect of a road surface. A typical STD range is between 2.0-0.8 mm. Roads with STD less than the lower threshold are more prone to traffic accidents due to aquaplaning or drop in skid resistance. Roads with STD more than the upper threshold are prone to fretting and pothole formation. In this study, a simple method to predict STD has been developed. The method utilises previous STD measurements collected by the Surface Condition Assessment for the National Network of Roads (SCANNER) method to quantify STD deterioration rate, which is the amount of increase or decrease in STD over time. The deterioration rates are then converted into Texture Deterioration Master Curves (TDMCs) which can be used in predicting STD. To demonstrate the application of this method, SCANNER data covering around 400 km of class A roads in Nottinghamshire collected between 2014 and 2018 were analysed and used to build TDMCs. STD data in 2020 were then predicted and compared to the measured STD data for validation. The results show that the developed method is simple and reliable, which makes it a valuable management tool for highway authorities enabling them predicting the STD on their road networks and assessing the risks of high or low STD on the condition and operation of their road networks

Predicting Pavement Performance Using Distress Deterioration Curves

Highway Authorities in the UK use Surface Condition Assessment for the National Network of Roads (SCANNER) in assessing and managing their road networks. This survey vehicle utilises laser measurements to detect and quantify most of the distress on the road surface, such as rutting, cracking and texture depth. It is however a data intensive and expensive approach since it is conducted annually. This study presents a simple method to predict pavement distress using previous SCANNER measurements. The previous measurements are used to develop Distress Deterioration Master Curves (DDMC) that relate distress deterioration rate with the severity of the distress. These curves can be used to predict future distress severity based on the current state without the need to provide further data such as pavement age or pavement material properties. To demonstrate the application of this method, a significant amount of SCANNER data covering around 400 km of class A roads in Nottinghamshire collected between 2014 and 2020 were analysed, and rutting, crack intensity, and texture depth were modelled in this study. DDMRs of these distress types were built based on data collected between 2014-2018, then 2020 data were used to validate the predictions. The results show that the developed method can be implemented in predicting surface distress of roads using previous measurements, which makes it a valuable addition tool for highway authorities subject to underfunding

Pothole 3D Reconstruction With a Novel Imaging System and Structure From Motion Techniques

Machine vision based evaluation systems are receiving increased attention, day by day, for automated quality inspection of roads. Industrial pavement scanners consist of laser scanners and are very expensive, hence inaccessible for everyone. The proposed work presents a simple and novel approach for 3D reconstruction of potholes for an automated inspection and road surface evaluation. The technique utilizes a Structure from Motion based 3D reconstruction algorithm, along with laser triangulation, to generate 3D point clouds of potholes. Alongside, a novel low-cost system, consisting of a single camera and a laser pointer, is also proposed. Keypoint matching techniques are employed, with the 5-point algorithm, on successive image frames to generate a point cloud. However, this point cloud is not metric yet, without scale information. The scale ambiguity is solved by making use of the laser pointer, and using the principle of triangulation. The laser spot is also detected in the same image sequence that is used for point-cloud building, cutting down the image capturing and processing overhead. The system has been benchmarked on artificial indentations with known dimensions, proving the robustness of the measurement scheme and hardware. Static and dynamic tests have been performed. The mean depth errors for measurement made by the imager statically and at dynamic speeds of 10 km/hr, 15 km/hr, and 20 km/hr are 5.3%, 7.9%, 14.4%, and 26.6%, whereas for perimeter the errors are 5.2%, 6.83 %, 11.8%, and 27.8%. The proposed, low-cost technique shows promising results in generating 3D point clouds for potholes

Comparative Neurological and Behavioral Assessment of Central and Peripheral Stimulation Technologies for Induced Pain and Cognitive Tasks

Pain is a multifaceted, multisystem disorder that adversely affects neuro-psychological processes. This study compares the effectiveness of central stimulation (transcranial direct current stimulation—tDCS over F3/F4) and peripheral stimulation (transcutaneous electrical nerve stimulation—TENS over the median nerve) in pain inhibition during a cognitive task in healthy volunteers and to observe potential neuro-cognitive improvements. Eighty healthy participants underwent a comprehensive experimental protocol, including cognitive assessments, the Cold Pressor Test (CPT) for pain induction, and tDCS/TENS administration. EEG recordings were conducted pre- and post-intervention across all conditions. The protocol for this study was categorized into four groups: G1 (control), G2 (TENS), G3 (anodal-tDCS), and G4 (cathodal-tDCS). Paired t-tests (p &lt; 0.05) were conducted to compare Pre-Stage, Post-Stage, and neuromodulation conditions, with t-values providing insights into effect magnitudes. The result showed a reduction in pain intensity with TENS (p = 0.002, t-value = −5.34) and cathodal-tDCS (p = 0.023, t-value = −5.08) and increased pain tolerance with TENS (p = 0.009, t-value = 4.98) and cathodal-tDCS (p = 0.001, t-value = 5.78). Anodal-tDCS (p = 0.041, t-value = 4.86) improved cognitive performance. The EEG analysis revealed distinct neural oscillatory patterns across the groups. Specifically, G2 and G4 showed delta-power reductions, while G3 observed an increase. Moreover, G2 exhibited increased theta-power in the occipital region during CPT and Post-Stages. In the alpha-band, G2, G3, and G4 had reductions Post-Stage, while G1 and G3 increased. Additionally, beta-power increased in the frontal region for G2 and G3, contrasting with a reduction in G4. Furthermore, gamma-power globally increased during CPT1, with G1, G2, and G3 showing reductions Post-Stage, while G4 displayed a global decrease. The findings confirm the efficacy of TENS and tDCS as possible non-drug therapeutic alternatives for cognition with alleviation from pain

Determination of sex from tooth pulp tissue

Objective: This study was carried out to determine the reliability of sex determination from teeth pulp tissue. Patients and methods: This study was carried on 60 maxillary and mandibular premolars and permanent molars (30 male teeth and 30 female teeth) which were indicated for extraction. The teeth were categorized into three groups of 20 each (10 from males and 10 from females).Group 1-pulp tissue from teeth examined immediately after extraction. Group 2- and Group 3-pulp tissue examined from teeth one and five month after extraction, respectively. Teeth was sectioned and pulpal cells were stained with quinacrine dihydrochloride. The cells were observed with fluorescent microscope for fluorescent body. Gender was determined by identification of Y chromosome fluorescence in dental pulp. Results: Freshly extracted teeth and for those examined one month later, sensitivity, specificity, positive predictive value, negative predictive value, and efficiency were all 100%. Conclusion: The fluorescent Y body test is shown to be a reliable, simple, and cost-effective technique for gender identification in the immediate postmortem period up to one month