In situ synthesis of a novel organic-inorganic composite as a non-noble metal electrocatalyst for the oxygen evolution reaction

Offering new techniques for efficient design and fabrication of inexpensive and earth-abundant catalysts for the development of oxygen evolution electrodes is a fundamental approach to promote sustainable energy processes. Herein, we report the in situ synthesis of a novel organic-inorganic composite directly onto carbon paste electrode (CPE) surface, as a robust substrate to incorporate Nickel-Iron (Ni-Fe) metal ions without using any binders or energy consumer techniques. Polyoxometalate (POM) and o-Anisidine (oA) are composite components that can be easily combined on the electrode surface (oA-POM/CPE). Ascribed to the synergy of context and metal ions, the as-prepared electrode affords a high catalytic activity and stability towards oxygen evolution reaction (OER), and gained a current density of 10 mA cm^?2 at overpotential of 330 mV. Moreover, the distinct electrocatalytic activity is illustrated by varying the amount of Fe in immersion solution, which proves the change made in percentage ratio of Ni-Fe in immersion solution that consequently affects Ni-Fe percentage value on electrode surface. This represents the competition between metal cations in creating complex with composite. Collectively, this simple strategy provides a promising way for the development of effective and non-noble metal-based OER electrocatalysts.     

A review on the natural gas potential of Pakistan for the transition to a low-carbon future

Natural gas is the world’s fastest growing and widely used fossil fuel which can be targeted for transitioning to a low-carbon future. Pakistan was ranked at seventh position among the utmost harmfully affected countries by climate change. It is, therefore, important to develop an effective energy policy toward the reduction of greenhouse gases in the country. This study evaluates the Pakistan’s natural gas industry development by reviewing reserves, production, consumption, infrastructures, and natural gas agreements in place. The total proven natural gas reserve of Pakistan is estimated to be 0.5 Tcm by the end of 2016. There are many active fields in Pakistan among which Sui gas reservoir is the largest. Currently, Pakistan’s natural gas industry is well matured with average size reserves, production capacity, and advanced and organized infrastructure for transmission and distribution network. Therefore, natural gas can be used to feed different sectors of the country, to decrease the financial burden of importing oil, and to reduce CO₂ emissions. However, increasing the gap of demand–supply for natural gas in the future, declining the average gas reserves, and postponing the gas import may challenge the natural gas industry, climate, and performance of Pakistan’s economy. Thus, these concerns must be addressed to help the natural gas industry for an easy transition to a low-carbon future.     

Cramer–Rao lower bounds and maximum likelihood timing synchronization for dirty template UWB communications

Timing acquisition constitutes a major challenge in realizing ultra-wideband communications. In this paper, we propose the timing with dirty template (TDT) approach as a promising candidate for achieving rapid, accurate and low-complexity acquisition. We describe the dirty template (DT) technique, in order to develop and test timing algorithms in both modes: data-aided (DA) and non-data- aided (NDA) modes. First, we derive the Cramer–Rao lower bound, which is used as a fundamental performance limit for any timing estimator. Next, the TDT acquisition estimator is achieved by using the Maximum Likelihood concept. Then we propose a new method, based on Time-Hoping codes, to improve the performance estimation of the original dirty template algorithms. Simulation shows the estimation error results of the modified method in the DA and NDA modes. It confirms the high performance and fast timing acquisition of DA mode, compared with NDA mode, but with less bandwidth efficiency.     

ZnO Nanoparticle Ionic Liquids Carbon Paste Electrode as a Voltammetric Sensor for Determination of Sudan I in the Presence of Vitamin B<Subscript>6</Subscript> in Food Samples

Room-temperature ionic liquid n-hexyl-3-methylimidazolium hexafluoro phosphate as a binder and ZnO nanoparticle (ZnO/NPs) as a sensor were used to construct a new ZnO/NPs carbon ionic liquid paste electrode (ZnO/NPs/IL/CPE), which exhibited enhanced electrochemical behavior as compared with the traditional carbon paste electrode with paraffin for electrooxidation of Sudan I. This modified electrode exhibited a potent and persistent electron mediating behavior followed by well separated oxidation peaks of Sudan I and vitamin B₆. The peaks current of square wave voltammograms (SWV) of Sudan I and vitamin B₆ increased linearly with their concentration in the ranges of 0.01–400 μM Sudan I and 0.5–800 μM vitamin B₆. The detection limits for Sudan I and vitamin B₆ were 0.008–0.2 μM, respectively. The modified electrode has been successfully applied for the assay of Sudan I and vitamin B₆ in food samples.     

Recovery length in sheathed spiral strands in deep-water platform applications

A theoretical model is presented for predicting the recovery length in any layer of an axially pre-loaded sheathed spiral strand experiencing external hydrostatic pressure. Based on a series of theoretical parametric studies, a straightforward method is proposed for obtaining reasonable estimates of variations in the recovery length in air for any layer of a strand with changes in the lay angle. Numerical results show that the magnitude of recovery length in sheathed spiral strands can be reduced substantially by subjecting the strand to high levels of external hydrostatic pressure, with the lay angle and (to a lesser extent) the strand mean axial load having some influence on the estimates of recovery length.     

Novel control for delay-locked loop in IR-UWB communication systems

Timing synchronization represents a major challenge in carrying out highly efficient ultra-wideband (UWB) communications. The delay-locked loop (DLL) method is widely proposed to maintain the satisfactory synchronization and reduce timing error. In this paper, the structure of DLL is modified by using the internal model control (IMC). This novel approach in the telecommunication systems has a good performance of overcoming disturbance and deviations of model parameters. Then the proposed IMC-DLL structure is developed, and by taking a linear Doppler Effect into account. This development is achieved by using the following two approaches: multi-model approach and moving average filter. Finally, the simulation results confirm that the proposed IMC-DLL system is able to achieve satisfactory and accurate tracking even in the presence of Doppler effect, and they also confirm that the proposed DLL has higher transient response, compared with the classical one.     

Effects of temperature and feed composition on catalytic dehydration of methanol to dimethyl ether over γ-alumina

Catalytic dehydration of methanol to dimethyl ether (DME) is performed in an adiabatic fixed bed heterogeneous reactor by using acidic γ-alumina. By changing the mean average temperature of the catalyst bed (or operating temperature of the reactor) from 233 up to 303 °C, changes in methanol conversion were monitored. The results showed that the conversion of methanol strongly depended on the reactor operating temperature. Also, conversion of pure methanol and mixture of methanol and water versus time were studied and the effect of water on deactivation of the catalyst was investigated. The results revealed that when pure methanol was used as the process feed, the catalyst deactivation occurred very slowly. But, by adding water to the feed methanol, the deactivation of the γ-alumina was increased very rapidly; so much that, by increasing water content to 20 weight percent by weight, the catalyst lost its activity by about 12.5 folds more than in the process with pure methanol. Finally, a temperature dependent model developed to predict pure methanol conversion to DME correlates reasonably well with experimental data.     

A highly sensitive method for simultaneous determination of ultra trace levels of copper and cadmium in food and water samples with luminol as a chelating agent by adsorptive stripping voltammetry

In the present study a selective method is presented for the simultaneous determination of copper and cadmium in food samples by adsorptive stripping voltammetry. In preliminary studies, it has been proven that the copper and cadmium react with 3-aminophthalhydrazide (luminol), giving rise to the formation of these complexes. These complexes have adsorptive characteristics on hanging mercury drop electrode (HMDE) and can be reduced in a reduction step. In this study the optimum reaction parameters and conditions studies are investigated. The calibration graphs were linear in the concentration range of 0.5–105.0 and 0.8–70.0 ng/ml for copper and cadmium, respectively. The limit of detection of the method was 0.04 ng/ml for Cu²⁺ and 0.02 ng/ml for Cd²⁺. The interference of some common ions was studied and it was concluded that application of this method for the determination of copper (II) and cadmium in food and water samples led to satisfactory results.