Electrocatalytic conversion of CO2 over in-situ grown Cu microstructures on Cu and Zn foils

Electrochemical conversion of carbon dioxide to value added multi-carbon products is of great importance and a promising approach to mitigate greenhouse gases. In this work, we report the fabrication of electrodes by depositing Cu over the metallic foils of Cu and Zn, which show high faradic efficiency for the conversion of CO2 to formic acid, acetate, and methanol. The morphology, phase and oxidation state of the Cu were different on the two foils while maintaining the same synthesis steps. The Cu particles embedded on Cu foil (Cu/Cu-foil) are in 3D cuboids form with flat and smooth faces, whereas Cu on Zn foil (Cu/Zn-foil) emerge in the shape of 3D flowers with the club of Cu microspikes grown perpendicularly from a root. For the electrocatalytic conversion of CO2, the Cu/Cu-foil shows a high selectivity for formic acid and ethyl acetate with the highest faradaic efficiency of 78 % at −0.3 V vs RHE, and 64 % at −1.0 V (vs RHE) for the two products, respectively. In contrast, the Cu/Zn-foil displays a high selectivity towards methanol, with the highest faradaic efficiency of 48 % at −1.0 V vs RHE, indicating that the product selectivity can be easily modulated by changing the metallic foil on which the Cu particles are deposited. Both the electrodes, Cu/Cu-foil and Cu/Zn-foil, show long-term stable performance while maintaining the selectivity of the products during CO2 electrocatalytic conversion

Preliminary Study on the Use of Reclaimed Asphalt in Public Works Authority Road Projects in the State of Qatar

This paper describes the outcomes of a preliminary study focused on the evaluation of four full-scale pavement sections in which reclaimed asphalt (RAP) was used in partial substitution of virgin aggregates during the production of asphalt mixes. Considered mixes were produced with different RAP percentages and were thereafter laid on site for the formation of asphalt base course layers of pavements in local roads of the State of Qatar. For comparative purposes, two trials included asphalt mixes containing no RAP, and in one case use was made of a rejuvenating agent. Activities carried out for the monitoring of field trials included analysis of component materials, critical observation of production and laying operations, assessment of the most relevant characteristics of produced asphalt mixes, and evaluation of the degree of compaction achieved during construction. Experimental results were of crucial importance for the introduction of RAP-related paving technologies in the State of Qatar, providing a meaningful background to the preparation of the "Ashghal Recycling Manual" issued by Ashghal and of the draft updated version of Qatar Construction Specifications

Engineering models for the design of long-lasting, sustainable, cost-efficient and climate-responsive pavements for Ashghal road projects in the State of Qatar

The planning, design, construction and management of modern transportation infrastructures is based on the use of continuously updated methodologies that consider, among others, the concept of sustainability. In such a context, for the specific case of road pavements, it is of crucial importance to carry out quantitative analyses based on the use of optimized engineering models. These models explicitly consider environment-pavement interactions, environmental impacts generated by all the components involved in the supply chain, and financial flows associated to pavement construction and maintenance. Such an approach is being adopted by the Public Works Authority (Ashghal) of the State of Qatar, that is developing and implementing models tailored for its infrastructure projects and local environmental conditions. This paper provides an overview of some of the employed models and methodologies that are based on the physics of pavement structures and on the assessment of environmental and economic indicators. It is shown that such an approach leads to significant improvements to current practice and to the enhanced use of recycled materials, while still guaranteeing required pavement performance

Electrooxidation of methanol on Ag, AgNi, and AgCo catalysts prepared by combustion synthesis technique

Herein, we report the synthesis of silver-based electrocatalysts (Ag/C, AgCo/C, and AgNi/C) using solution combustion method and their performance towards methanol oxidation reaction. Detailed structural and microscopic analysis confirmed the formation of graphitic carbon, synthesis of crystalline phases with high porosity in all the three electrocatalysts. X-ray photoelectron spectroscopic (XPS) analysis showed a high concentration of Ag2O (or Ag+) on AgNi/C, whereas AgCo/C exhibited a high concentration AgO (or Ag2+) on the surface. XPS analysis on C 1s confirmed the highest concentrations of the sp2 hybridized C-C bond on Ag/C, C-O on AgNi/C, and O-C-O bond on AgCo/C, respectively. The X-ray absorption spectroscopy (XAS) analysis on Ag edge showed a similarity in the bond lengths in AgCo and AgNi samples to that of bulk silver, that has a bond length of 2.89 Å, with only silver-silver scattering and the absence of a different or a nonsilver metal in the nanoparticles. This indicates that there is no Ag-M alloying. Nonetheless, a significant difference in particle sizes was observed, with 2.5 and 6 nm, respectively for AgNi and AgCo. Methanol electrooxidation experiments performed on the electrocatalysts indicated AgNi/C to show better performance in comparison to AgCo/C and Ag/C. Anodic polarization curves obtained from linear sweep voltammetry (LSV) measurements demonstrated a superior performance of AgNi/C with an onset potential of 0.41 V. In addition, 20 h chronoamperometry experiment also confirmed a sustained superior performance of AgNi/C catalyst, which could be due to smaller particle size and stabilization of Ag+ on the surface of the catalyst.This work was made possible by the NPRP grant (NPRP13S‐0109‐200029 and NPRP8‐145‐2‐066) from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors. Use of the Advanced Photon Source is supported by the U.S. Department of Energy, Office of Science, and Office of Basic Energy Sciences, under contract DE‐AC02‐06CH11357. Authors would also like to acknowledge Dr. Md. Abdul Matin for his initial support on catalysts synthesis and characterization. The authors would also like to acknowledge QEERI Core Labs for their support related to the TEM characterization

Enhancement Of Water-oil Separation By Electroclescence

Dispersed water droplets in organic liquids are commonly encountered in the oil, chemical and biochemical industries. A typical example is the separation of dispersed water drops in crude oil, in order to prevent catalyst fouling, viscosity and volume increase, and to meet quality specifications of the crude oil. Water drops can be removed from a continuous oil phase by various techniques, such as chemical demulsification, gravity or centrifugal separation, pH adjustment, filtration, heat treatment, membrane separation and electrostatic-enhanced coalescence. Compared to other methods, electrical demulsification is considered to be superior in terms of energy efficiency. The electrostatic effects arise from the much higher values of dielectric permittivity and conductivity of water in comparison to oil. However, the mechanism of electrocoalescence is still not fully understood and most of the conventional electro-separators are rather bulky. There is, therefore, a compelling need to optimize the design and operation of these separators by means of a better fundamental understanding of the underlying physics. This study aims at investigating the coalescence behaviour of water droplets in sunflower oil when the aqueous phase is present in the form of a chain of droplets. Chains easily form in an emulsion, since droplets tend to align themselves with the direction of the electric field. A pair of ladder-wise electrodes was implemented to set up an electric field almost parallel to the flow direction of the droplets. This design ensures that adjacent droplets in a chain experience the maximum attractive force and does not significantly disturb the hydrodynamics of the continuous phase. The effect of the electric field strength, frequency and waveform on the process performance has been investigated. Both constant and pulsed dc fields have been applied to the dispersion. Sinusoidal, sawtooth and square waves have been employed as pulsed dc waveforms. Droplet size distributions at the outlet of the device were measured by image analysis. The outcomes of the research suggest that it is possible to find a combination of electrical field intensity, frequency and waveform to maximize the separation efficiency.qscienc

Heat Stroke in Emergency Department: Diagnosis and Management

Background: Heat stroke is a severe health concern with the potential for multi-organ failure, necessitating rapid and effective management. With rising global temperatures, there is increasing concern regarding the vulnerability of populations in high-heat areas, notably in Saudi Arabia, especially during the annual Hajj pilgrimage. Objective: This paper aims to review the epidemiology, evaluation and management techniques of heat stroke, emphasizing the situation during Hajj pilgrimages in Saudi Arabia, and to outline the best practices for emergency management. Methodology: A comprehensive review of literature and studies related to heat stroke, both globally and specific to Saudi Arabia, was undertaken. An in-depth analysis of emergency management, including initial assessment, cooling methods, organ support, medication, and prevention strategies, was conducted. Results: Heat stroke remains a significant cause of emergency department visits, with specific groups, such as men and the elderly, being more susceptible. During the Hajj in 2016, 267 patients were diagnosed with heat-related illnesses, with heatstroke accounting for 29% of these cases. With the threat of global warming, studies indicate a potential tenfold increase in heat stroke risk with a 2°C rise in temperatures. Swift and comprehensive cooling is pivotal for recovery. Management emphasizes rapid recognition, assessment, and varied cooling methods, along with targeted treatments for organ dysfunctions. Prevention strategies play a vital role, given the higher efficacy and practicality over treating organ dysfunctions. Conclusion: Heat stroke is a pressing health challenge, particularly in high-risk environments like Saudi Arabia during the Hajj pilgrimage. While effective emergency management protocols exist, an emphasis on prevention is crucial. It is imperative to incorporate a comprehensive approach to address both the immediate threat and long-term risks of heat stroke, especially with the looming challenge of global warming

Pathological, microscopic, and molecular diagnosis of paratuberculosis/John’s disease in naturally infected dromedary camel (Camelus dromedarius)

Background and Aim: Paratuberculosis (PTB) or John’s disease is a chronic disease of ruminants impeding the reproduction and productivity of the livestock sector worldwide. Since there is a lack of pathological studies explaining the nature and development of the disease in camels, this study aimed to highlight the anatomopathological changes of PTB in camels, which may help in verifying and validating some diagnostic tests used to detect the etiology of the disease in camel tissues. Materials and Methods: In August 2017, at Alselaa border’s Veterinary Clinic of Al Dhafra Region, Western Abu Dhabi, UAE, one imported culled she-camel of 2 years old was subjected to clinical, microscopic, and anatomopathological investigations along with real-time quantitative polymerase chain reaction (q-PCR) to confirm the infection and correlate between clinical signs and pathological lesions of the PTB in dromedary camels. Results: Clinically, typical clinical signs compliant with the pathognomonic gross and histologic lesions of PTB were seen in naturally infected dromedary camel. As presumptive diagnosis microscopically, acid-fast coccobacillus bacterium clumps were demonstrated in direct fecal smears as well as in scraped mucosal and crushed mesenteric lymph node films, and in histopathological sections prepared from a necropsied animal and stained by Ziehl-Neelsen stain. Free and intracellular acid-fast clump phagosomes were further confirmed as Mycobacterium avium subsp. paratuberculosis by q-PCR. Conclusion: Clinical signs and pathological lesions of paratuberculosis in a dromedary camel were found to be similar to those of the other susceptible hosts

Area-Specific Traffic Peak Hour Timing Using Traffic Signal Detectors: A Case Study of Qatar

This case study addresses peak hour traffic timing in Qatar after COVID-19 as traffic conditions returned to normal. Traffic data were provided for multiple areas, mainly around Doha City. Flow data were obtained from traffic signal detectors for 318 intersections. The peak periods in morning, mid-day, and evening were 06:30 am–08:30 am, 12:30 pm–2:30 pm, and 5:15 pm–7:15 pm, respectively. These findings align with the Ministry of Transport’s state-wide study (Transportation Masterplan for Qatar, 2018). We found traffic in Qatar to differ on Thursday, Friday, and Saturday versus the rest of the week due to the weekend effect. Results offer useful insights for policymakers to reduce congestion and provide complex traffic solutions (e.g., understanding land use–specific peak hour timing, imposing zone-specific working hours). In addition, this case study highlights the potential to use existing infrastructure to expand traffic studies in Qatar at minimum cost

Synthesis of fumed silica supported Ni catalyst for carbon dioxide conversion to methane

In this study, we report the synthesis of a fumed silica supported Ni-based catalyst for carbon dioxide conversion to methane. Ni/fumed-SiO2 was prepared by loading the active agent precursor solution on the high surface area fumed SiO2 through the wet impregnation technique. Thereafter, the resulting powder was dried and reduced under hydrogen flow at 750°C for 3 h to get the desired active agent. The CO2 catalytic hydrogenation was performed using a flow reactor between 50 and 650°C temperature, where it showed good catalytic activity and selectivity for methane. In addition, it is found to be highly stable under reaction conditions for 16 h time on stream. Fresh and used (after the stability test) catalyst samples were characterized using different techniques, such as XRD, TEM, SEM/EDX, to investigate the structural and morphological properties, and effect of exposure to reaction conditions on the catalysts. Furthermore, the reaction mechanism was investigated using in-situ DRIFT in the temperature range 50–450°C. The results revealed the formation of formate species at early reaction stages, followed by CO that was detected as linearly adsorbed on Ni surface, and lastly methane formation. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd.This publication was made possible by NPRP grant (NPRP8-509-2-209) from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors. The authors also gratefully acknowledge the Center for Advanced Materials (CAM) at Qatar University for services related to XRD analysis. The SEM and TEM analysis were accomplished in the Central Laboratory Unit, Qatar University and the authors greatly appreciate their assistance in the characterization of the samples.Scopu

Synthesis of fumed silica supported Ni catalyst for carbon dioxide conversion to methane

In this study, we report the synthesis of a fumed silica supported Ni-based catalyst for carbon dioxide conversion to methane. Ni/fumed-SiO2 was prepared by loading the active agent precursor solution on the high surface area fumed SiO2 through the wet impregnation technique. Thereafter, the resulting powder was dried and reduced under hydrogen flow at 750°C for 3 h to get the desired active agent. The CO2 catalytic hydrogenation was performed using a flow reactor between 50 and 650°C temperature, where it showed good catalytic activity and selectivity for methane. In addition, it is found to be highly stable under reaction conditions for 16 h time on stream. Fresh and used (after the stability test) catalyst samples were characterized using different techniques, such as XRD, TEM, SEM/EDX, to investigate the structural and morphological properties, and effect of exposure to reaction conditions on the catalysts. Furthermore, the reaction mechanism was investigated using in-situ DRIFT in the temperature range 50–450°C. The results revealed the formation of formate species at early reaction stages, followed by CO that was detected as linearly adsorbed on Ni surface, and lastly methane formation. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd.This publication was made possible by NPRP grant (NPRP8-509-2-209) from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors. The authors also gratefully acknowledge the Center for Advanced Materials (CAM) at Qatar University for services related to XRD analysis. The SEM and TEM analysis were accomplished in the Central Laboratory Unit, Qatar University and the authors greatly appreciate their assistance in the characterization of the samples.Scopu