S. Zahid

Metal nanoframes have gained tremendous attention in the domain of modern research and development due to their distinctive 3D spatial structure, efficient physiochemical properties, and comparatively good activity. Different strategies have been implicated by the researchers to design nano frame of varying chemical nature and shapes. Most of the synthetic protocols being adopted to design a nano framee, mainly consist of two main steps, nucleation and growth of solid particles and secondly excavation of the interiors. In this context, many synthetic methods are overviewed. To show their unprecedented performance or activity, a few applications in catalytic, biomedical, theranostic, SERS, sensing of different materials, reduction of CO2, etc are also discussed.

Some global difficulties in the modern period include energy storage conversion. Researchers have looked to renewable energy resources to discover long-term answers to this dilemma. Fuel cells are one example of prospective energy producing technology. Although these technologies appear to be very enticing, they are known to be expensive due to high expenses. Catalyst costs, as well as concerns concerning energy density. Pt based Electrocatalysts have traditionally been used to drive ORR and offer efficient power outputs. However, cost constraints have limited the use of these electrocatalysts, rendering them inefficient. Apart from the high price, Pt-based Electrodes are prone to time-dependent drift and CO deactivation, both of which occur gradually. Electrocatalysts deteriorate over time, reducing the efficiency of fuel cells. This is why alternative electrocatalysts are in high demand for future energy applications. This review covers the comparative study of Platinium and Non-Platinium based electrocatalyst in fuel cells, their shortcomings and recent advancement for efficient and optimized electrocatalyst.

Metal nanoframes have gained tremendous attention in the domain of modern research and development due to their distinctive 3D spatial structure, efficient physiochemical properties, and comparatively good activity. Different strategies have been implicated by the researchers to design nanoframes of varying chemical natures and shapes. Most of the synthetic protocols being adopted to design nanoframes consist of two main steps: nucleation and the growth of solid particles and, secondly, excavation of the interiors. In this context, many synthetic methods are overviewed. To show their unprecedented performance or activity, a few applications in catalysis, biomedicine, theranostics, SERS, the sensing of different materials, the reduction of CO2, etc., are also discussed.

Use of credit card is very common these days. And the number of frauds related to credit cards are also increasing. With the increase in the usage of internet, many organizations have shifted their work from offline to online. Same is the case with financial department. On one side, this thing has increased the ease of people but on the other hand, number of frauds have been tremendously increased. On one side, people are doing shopping without cash, paying bills without standing in long queues, doing booking online and on the other side fake accounts, scamming, credit card frauds have been increased resulting in huge amount of loss to financial system every year. Fraud is a criminal activity done by un authorized person. Credit card frauds are very common these days. There are many types of credit card frauds. Sometime they do fake calls or messages and sometimes they steal customer’s online information. Many techniques using machine learning models have been implemented in order to stop these types of frauds. But fraudsters are sometimes by pass theses traditional protective systems and make successful transaction. Traditional machine learning models are not capable enough to detect frauds using sequence of data. For this purpose, neural networks are recently used. In this paper, six machine learning algorithms are applied. Among them Random Forest and Extra trees classifier are best. And in case of neural networks, long short-term memory LSTM is best. Obtained results outperform the existed work that have been previously done in this field.

Four different flow characteristics obtained from Eulerian finite element method (FEM) simulations using a Mohr-Coulomb material model are quantitatively compared to experiments performed on laboratory-scale concentric and eccentric quasi two-dimensional flat-bottomed bins. Particle image velocimetry (PIV) experiments are performed on Ottawa 20–30 sand discharging through the bins. The experimental steady state velocity profiles, mass discharge rate (MDR), duration of steady MDR (TSS), and free surface profiles are compared to the FEM predictions. The significance of material dilation and associated softening (DS) on FEM flow characteristics is examined through comparisons to simulations without dilation or softening (NDNS). FEM DS simulations using a Mohr-Coulomb material model that includes material dilation and softening are shown to be capable of predicting the four flow characteristics in both discharging bins with reasonable accuracy.

Test beam results of a calorimetric module based on 3×3×22 cm3 PbWO4 crystals, identical to those used in the CMS ECAL Endcaps, read out by a pair of photodetectors coupled to the two opposite sides (front and rear) of each crystal are presented. Nine crystals with different level of induced absorption, from 0 to 20 m−1, have been tested using electrons in the 50–200 GeV energy range. Photomultiplier tubes have been chosen as photodetectors to allow for a precise measurement of highly damaged crystals. The information provided by this double side read-out configuration allows to correct for event-by-event fluctuations of the longitudinal development of electromagnetic showers. By strongly mitigating the effect of non-uniform light collection efficiency induced by radiation damage, the double side read-out technique significantly improves the energy resolution with respect to a single side read-out configuration. The non-linearity of the response arising in damaged crystals is also corrected by a double side read-out configuration and the response linearity of irradiated crystals is restored. In high radiation environments at future colliders, as it will be the case for detectors operating during the High Luminosity phase of the Large Hadron Collider, defects can be created inside the scintillator volume leading to a non-uniform response of the calorimetric cell. The double side read-out technique presented in this study provides a valuable way to improve the performance of calorimeters based on scintillators whose active volumes are characterized by high aspect ratio cells similar to those used in this study.

Vacuum phototriodes have been used for a number of years in particle physics experiments. For example, they were used in the OPAL experiment at LEP and are currently used in the endcap calorimeter of the CMS experiment at CERN’s Large Hadron Collider. A simulation of a CMS vacuum phototriode (RIE type FEU-188) has been implemented using the COMSOL multi-physics software environment. In addition, a new vacuum phototriode configured with a segmented anode, to provide four independent channels within the same overall device envelope, is presented. The induced signal as a function of time, and the effects of cross-talk in adjacent quadrants have been studied.

A new four-fold segmented multi-anode vacuum phototriode is presented. A simulation using the COMSOL multi-physics simulation software is described and the predicted induced signals on the anode and the inter-anode cross-talk calculated. Experimental data on the spatial uniformity of the response across the photocathode, the cross talk between segments and the dark currents at room temperature are presented. The response of the VPT at 14 degrees to a magnetic field of up to 4 T is determined.